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Sample records for stage ii mantle

  1. Mantle irradiation alone for pathologic stage I and II Hodgkin's disease: long-term follow-up and patterns of failure

    International Nuclear Information System (INIS)

    Liao Zhongxing; Ha, Chul S.; Vlachaki, Maria T.; Hagemeister, Frederick; Cabanillas, Fernando; Hess, Mark; Tucker, Susan; Cox, James D.

    2001-01-01

    Purpose: We performed a retrospective study to determine the long-term outcome, patterns of failure, and prognostic factors for patients with pathologic Stage I or II Hodgkin's disease (HD) who were treated with mantle irradiation alone. Methods and Materials: The medical records of 145 patients with pathologic Stage I or II supradiaphragmatic Hodgkin's disease treated with mantle irradiation alone between June 1967 and June 1991 were reviewed. Patterns of failure, overall survival (OS) rate, and progression-free survival (PFS) rate were determined. Univariate and multivariate analyses were performed to identify adverse prognostic factors for OS and PFS. The number of adverse prognostic factors per patient was counted, and a prognostic score was assigned to each patient. The log-rank test was used to compare the OS or PFS rates among patients with prognostic scores 0, 1, and 2. Results: The median patient age was 27 years (range 10-66), with almost even male to female distribution. Every patient had splenectomy and negative laparotomy (LAP). Fifty-one patients had Stage I disease (IA-49, IB-2) and 94 Stage II (IIA-89, IIB-5). The histologic subtypes were nodular sclerosing in 110, mixed cellularity in 28, lymphocyte predominance in 5, lymphocyte depleted in 1, and unclassified in 1. Twelve patients with Stage II disease had ≥ 3 sites of nodal involvement. Fifty-four patients had a prognostic score of 0, 70 of 1, and 21 of 2. The median follow-up time for the 109 surviving patients was 146 months (range 25-381). The 10- and 20-year actuarial OS rates for the whole group were 87.6% and 65.3%, respectively. The corresponding actuarial PFS rates were 75.3% and 74.2%, respectively. Thirty-six patients (9 Stage I, 27 Stage II) had relapses in a total of 41 sites. Failures by histology were 29 patients with nodular sclerosing, 6 with mixed cellularity, and 1 with lymphocyte predominance. Failures by sites were: trans-diaphragmatic, 22 (para-aortic nodes, 15; as the only

  2. Early-stage mantle cell lymphoma

    DEFF Research Database (Denmark)

    Dabaja, B S; Zelenetz, A D; Ng, A K

    2017-01-01

    Background: Mantle cell lymphoma (MCL) rarely presents as early-stage disease, but clinical observations suggest that patients who present with early-stage disease may have better outcomes than those with advanced-stage disease. Patients and methods: In this 13-institution study, we examined...

  3. Management Trends and Outcomes for Stage I to II Mantle Cell Lymphoma Using the National Cancer Data Base: Ascertaining the Ideal Treatment Paradigm

    International Nuclear Information System (INIS)

    Gill, Beant S.; Vargo, John A.; Pai, Sarah S.; Balasubramani, Goundappa K.; Beriwal, Sushil

    2015-01-01

    Purpose: Mantle cell lymphoma (MCL) is a rare, albeit aggressive subset of non-Hodgkin lymphoma, resulting in varied treatment approaches. Given the paucity of data defining the optimal management for early-stage MCL, we conducted an analysis using the National Cancer Data Base (NCDB) to identify practice patterns and outcomes. Methods and Materials: The NCDB was queried for patients with stage I to II MCL diagnosed from 1998 to 2012 receiving chemotherapy (CT) or radiation therapy (RT), or both (CT+RT). Univariate and multivariable analyses for factors associated with treatment selection were completed using logistic regression. Propensity scores with inverse probability treatment weighting (IPTW) were calculated based on the conditional probability of receiving CT+RT. The log-rank test and Cox proportional hazards modeling with IPTW adjustment were conducted for the survival analyses. Results: In total, 2539 patients were identified. The key characteristics were as follows: 69% were male, 71% were aged ≥60 years, 28% had extranodal involvement, and 51% had stage I disease. Of the 2539 patients, 70% underwent CT, 11% underwent RT, and 19% underwent CT+RT. The use of CT+RT decreased from 23.1% to 14.1% in 1998 to 2002 and 2010 to 2012 (P<.001). CT+RT usage was lower for patients with the following characteristics: age ≥60 years, female sex, stage II disease, and the presence of B symptoms. With a median follow-up period of 42.8 months, the unadjusted 3-year overall survival estimates for patients receiving CT, RT, or CT+RT were 67.8%, 72.4%, and 79.8%, respectively (P<.001). After correcting for indication bias through IPTW-adjusted modeling, CT+RT reduced the risk of overall mortality compared with monotherapy (hazard ratio 0.65, P=.029). Conclusions: Although uncommon, patients with stage I-II MCL can have favorable outcomes. Despite a continued decline in the usage of consolidative RT, combined modality therapy improves survival in this cohort compared

  4. Management Trends and Outcomes for Stage I to II Mantle Cell Lymphoma Using the National Cancer Data Base: Ascertaining the Ideal Treatment Paradigm

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    Gill, Beant S.; Vargo, John A. [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Pai, Sarah S. [Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (United States); Balasubramani, Goundappa K. [Department of Epidemiology, Epidemiology Data Center, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania (United States); Beriwal, Sushil, E-mail: beriwals@upmc.edu [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States)

    2015-11-01

    Purpose: Mantle cell lymphoma (MCL) is a rare, albeit aggressive subset of non-Hodgkin lymphoma, resulting in varied treatment approaches. Given the paucity of data defining the optimal management for early-stage MCL, we conducted an analysis using the National Cancer Data Base (NCDB) to identify practice patterns and outcomes. Methods and Materials: The NCDB was queried for patients with stage I to II MCL diagnosed from 1998 to 2012 receiving chemotherapy (CT) or radiation therapy (RT), or both (CT+RT). Univariate and multivariable analyses for factors associated with treatment selection were completed using logistic regression. Propensity scores with inverse probability treatment weighting (IPTW) were calculated based on the conditional probability of receiving CT+RT. The log-rank test and Cox proportional hazards modeling with IPTW adjustment were conducted for the survival analyses. Results: In total, 2539 patients were identified. The key characteristics were as follows: 69% were male, 71% were aged ≥60 years, 28% had extranodal involvement, and 51% had stage I disease. Of the 2539 patients, 70% underwent CT, 11% underwent RT, and 19% underwent CT+RT. The use of CT+RT decreased from 23.1% to 14.1% in 1998 to 2002 and 2010 to 2012 (P<.001). CT+RT usage was lower for patients with the following characteristics: age ≥60 years, female sex, stage II disease, and the presence of B symptoms. With a median follow-up period of 42.8 months, the unadjusted 3-year overall survival estimates for patients receiving CT, RT, or CT+RT were 67.8%, 72.4%, and 79.8%, respectively (P<.001). After correcting for indication bias through IPTW-adjusted modeling, CT+RT reduced the risk of overall mortality compared with monotherapy (hazard ratio 0.65, P=.029). Conclusions: Although uncommon, patients with stage I-II MCL can have favorable outcomes. Despite a continued decline in the usage of consolidative RT, combined modality therapy improves survival in this cohort compared

  5. Vorinostat, Rituximab, Ifosfamide, Carboplatin, and Etoposide in Treating Patients With Relapsed or Refractory Lymphoma or Previously Untreated T-Cell Non-Hodgkin Lymphoma or Mantle Cell Lymphoma

    Science.gov (United States)

    2017-04-17

    Adult Nasal Type Extranodal NK/T-cell Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Contiguous Stage II Mantle Cell Lymphoma; Cutaneous B-cell Non-Hodgkin Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Mantle Cell Lymphoma; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Grade III Lymphomatoid Granulomatosis; Recurrent Adult Hodgkin Lymphoma; Recurrent Adult Immunoblastic Large Cell Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Recurrent Small Lymphocytic Lymphoma; Splenic Marginal Zone Lymphoma; Stage I Cutaneous T-cell Non-Hodgkin Lymphoma; Stage I Mantle Cell Lymphoma; Stage I Mycosis Fungoides/Sezary Syndrome; Stage II Cutaneous T-cell Non-Hodgkin Lymphoma; Stage II Mycosis Fungoides/Sezary Syndrome; Stage III Cutaneous T-cell Non-Hodgkin Lymphoma; Stage III Mantle Cell Lymphoma; Stage III Mycosis Fungoides/Sezary Syndrome; Stage IV Cutaneous T-cell Non-Hodgkin Lymphoma; Stage IV Mantle Cell Lymphoma; Stage IV Mycosis Fungoides/Sezary Syndrome; Waldenström Macroglobulinemia

  6. Survival of the primitive mantle reservoir?

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    Huang, S.; Jacobsen, S. B.; Mukhopadhyay, S.

    2010-12-01

    is well accepted that the Koolau source is not primitive mantle. 4. Different suites of OIBs form different 207Pb*/206Pb*-4He/3He trends and importantly, they do not converge to a single point, implying that there is no single high-3He mantle source “parental to all mantle reservoirs”. In addition, some OIBs plot to the left of the 4.567 Gyr geochron. If the OIB Pb isotopes yield age information of their sources, these sources are inferred to be older than the Solar System. We suggest a simpler and alternative explanation: the 3He-rich mantle sources are mixtures of the primitive mantle and later recycled components. Because the recycled components have lower He/Pb than the primitive mantle, the low 4He/3He will not be erased by this mixing process, but the Pb budget could be completely dominated by the recycled components. 5. Single-stage Pb model ages relative to the initial Solar System Pb isotope composition should be interpreted with care. They are not strictly valid unless i) the whole Earth has a very low U/Pb, so that there is essentially no Pb isotopic evolution in the mantle until the core formation, and ii) the core formed in a single event rather than by continuous metal segregation. Jackson M. G. et al (2010) Nature 466, 853-856.

  7. Long term results of mantle irradiation(MRT) alone in 261 patients with clinical stage I-II supradiaphragmatic Hodgkin's disease

    International Nuclear Information System (INIS)

    Wirth, A.; Byram, D.; Chao, M.; Corry, J.; Davis, S.; Kiffer, J.; Laidlaw, C.; Quong, G.; Ryan, G.; Liew, K.

    1997-01-01

    Purpose: We report our results using MRT for clinical stage I-II HD and assess the value of published prognostic criteria in our study population. Pts and Methods: Between 1969 and 1994, 261 pts were treated with MRT alone for clinical stage I-II supradiaphragmatic HD. Pt characteristics: median age-30; M-54%/F-46%; stage IA-52%, IB-2%, IIA-37%, IIB-8%; histology LP-21%, NS-51%, MC-23%, other 5%; median ESR 18. CT abdomen and LAG were performed in 61% and 60% respectively. No pt had prior staging laparotomy. No pt received infradiaphragmatic RT. Central axis dose was 32 Gy-36 Gy. Univariate analysis was performed for prognostic factors for progression-free (PFS) and overall survival(OS). Outcome was assessed in favourable subsets as defined by: EORTC (v. favourable: CSIA, LP or NS histology, age < 40, female, no bulk, ESR < 50; favourable: CSI-II, age < 50, < 4 sites, no bulky mediastinal mass, ESR < 50 with no B symptoms or ESR < 30 with B symptoms); Princess Margaret Hospital (PMH) (IA-IIA, LP or NS histology, ESR < 40, age < 50, no large mediastinal mass, no E lesion). Results: 261 pts completed RT, with 5% requiring treatment interruption for toxicity. Significant factors (P<0.05) for PFS were stage, performance status, histology, B symptoms, number of sites, ESR and bulk. Significant factors (P<0.05) for OS were age, performance status, histology and B symptoms. (The results of a multivariate analysis will be presented.) Results in our study population using published prognostic criteria (in %): Thirty-six percent progressed following RT: 8% in-field; 24% out of field only (including 10% in the paraaortic/splenic region alone); 4% marginal; Fifty-seven percent of relapsed pts remain progression free after subsequent salvage treatment. Two cases of acute leukaemia, 8 cases of non-Hodgkin's lymphoma and 14 (non-skin) carcinomas occurred, of which 11 were in-field. Seventy pts have died. The cause was: HD 41%; other malignancy 20%; cardiovascular 17%; other 15

  8. MANTLE-CRUST INTERACTION AT THE LATE STAGE OF EVOLUTION OF HERCYNIAN ALTAI COLLISION SYSTEM, WESTERN PART OF CAOB

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    S. V. Khromykh

    2017-01-01

    Full Text Available Altai collision system of Hercynides was formed in Late Paleozoic as a result of oblique collision of Siberian continent and Kazakhstan composed terrane [Vladimirov et al., 2003; 2008; Xiao et al., 2010]. At the late stages of its evolution (time interval from 310–300 to 280–270 Ma the huge different mafic and felsic magmatism occurred at the territory (Fig. 1 [Vladimirov et al., 2008; Khromykh et al., 2011, 2013, 2014, 2016; Kotler et al., 2015; Sokolova et al., 2016]. It is evident about increased thermal gradient in lithosphere and about significant role of mantle and active manifestation of mantle-crust interactions. Some magmatic complexes may be considered as indicators of mantle-crust interaction processes.

  9. Post orchiectomy management in stage II testicular seminoma

    International Nuclear Information System (INIS)

    Singhal, S.; Dixit, S.; Ramana Murthy, R.; Neema, J.P.; Vyas, R.K.; Baboo, H.A.

    1994-01-01

    Twenty eight patients with stage II A and twenty patients with stage II B testicular seminoma were treated at this institute between January 1982 and December 1988. The three year crude survival observed in this retrospective analysis was 82% and 75% respectively. Post orchiectomy infradiaphragmatic radiotherapy was the mainstay of the treatment. In stage II A, 4 patients were administered adjuvant chemotherapy as well. Prophylactic mediastinal irradiation (PMI) was not employed as a routine in this subgroup. Eight patients (28%) relapsed (mediastinal nodes - 4, pulmonary - 3, scrotal - 1). In stage II B, twelve patients were treated with primary abdominal radiotherapy and of them 4 were delivered PMI as well. Induction chemotherapy was administered in remaining 8 patients. Seven patients (35%) relapsed (pulmonary-4, mediastinal nodes-3). Mediastinal recurrence was noted only in those who were treated with abdominal radiotherapy alone. Though salvage chemotherapy proved successful in 5 of the seven patients (70%) with nodal relapse, none of the patients with extranodal relapse responded to subsequent chemotherapy. For stage II A abdominal radiotherapy alone is recommended and for stage II B induction chemotherapy is advised keeping radiotherapy reserved for residual mass. PMI as a routine in stage II testicular seminoma is not advocated as no survival benefit is observed. (author) 15 refs., 6 tabs

  10. Lenalidomide-bendamustine-rituximab in untreated mantle cell lymphoma > 65 years with untreated mantle cell lymphoma

    DEFF Research Database (Denmark)

    Albertsson-Lindblad, Alexandra; Kolstad, Arne; Laurell, Anna

    2016-01-01

    For elderly patients with mantle cell lymphoma (MCL), there is no defined standard therapy. In this multicenter open-label phase I/II trial we evaluated the addition of lenalidomide (LEN) to rituximab-bendamustine (R-B) as first-line treatment to elderly MCL patients. Patients >65 years with untr......For elderly patients with mantle cell lymphoma (MCL), there is no defined standard therapy. In this multicenter open-label phase I/II trial we evaluated the addition of lenalidomide (LEN) to rituximab-bendamustine (R-B) as first-line treatment to elderly MCL patients. Patients >65 years...

  11. Evaluation of lymph node numbers for adequate staging of Stage II and III colon cancer

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    Bumpers Harvey L

    2011-05-01

    Full Text Available Abstract Background Although evaluation of at least 12 lymph nodes (LNs is recommended as the minimum number of nodes required for accurate staging of colon cancer patients, there is disagreement on what constitutes an adequate identification of such LNs. Methods To evaluate the minimum number of LNs for adequate staging of Stage II and III colon cancer, 490 patients were categorized into groups based on 1-6, 7-11, 12-19, and ≥ 20 LNs collected. Results For patients with Stage II or III disease, examination of 12 LNs was not significantly associated with recurrence or mortality. For Stage II (HR = 0.33; 95% CI, 0.12-0.91, but not for Stage III patients (HR = 1.59; 95% CI, 0.54-4.64, examination of ≥20 LNs was associated with a reduced risk of recurrence within 2 years. However, examination of ≥20 LNs had a 55% (Stage II, HR = 0.45; 95% CI, 0.23-0.87 and a 31% (Stage III, HR = 0.69; 95% CI, 0.38-1.26 decreased risk of mortality, respectively. For each six additional LNs examined from Stage III patients, there was a 19% increased probability of finding a positive LN (parameter estimate = 0.18510, p Conclusions Thus, the 12 LN cut-off point cannot be supported as requisite in determining adequate staging of colon cancer based on current data. However, a minimum of 6 LNs should be examined for adequate staging of Stage II and III colon cancer patients.

  12. Gene expression profiles in stages II and III colon cancers

    DEFF Research Database (Denmark)

    Thorsteinsson, Morten; Kirkeby, Lene T; Hansen, Raino

    2012-01-01

    PURPOSE: A 128-gene signature has been proposed to predict outcome in patients with stages II and III colorectal cancers. In the present study, we aimed to reproduce and validate the 128-gene signature in external and independent material. METHODS: Gene expression data from the original material...... were retrieved from the Gene Expression Omnibus (GEO) (n¿=¿111) in addition to a Danish data set (n¿=¿37). All patients had stages II and III colon cancers. A Prediction Analysis of Microarray classifier, based on the 128-gene signature and the original training set of stage I (n¿=¿65) and stage IV (n...... correctly predicted as stage IV-like, and the remaining patients were predicted as stage I-like and unclassifiable, respectively. Stage II patients could not be stratified. CONCLUSIONS: The 128-gene signature showed reproducibility in stage III colon cancer, but could not predict recurrence in stage II...

  13. Upper mantle fluids evolution, diamond formation, and mantle metasomatism

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    Huang, F.; Sverjensky, D. A.

    2017-12-01

    During mantle metasomatism, fluid-rock interactions in the mantle modify wall-rock compositions. Previous studies usually either investigated mineral compositions in xenoliths and xenocrysts brought up by magmas, or examined fluid compositions preserved in fluid inclusions in diamonds. However, a key study of Panda diamonds analysed both mineral and fluid inclusions in the diamonds [1] which we used to develop a quantitative characterization of mantle metasomatic processes. In the present study, we used an extended Deep Earth Water model [2] to simulate fluid-rock interactions at upper mantle conditions, and examine the fluids and mineral assemblages together simultaneously. Three types of end-member fluids in the Panda diamond fluid inclusions include saline, rich in Na+K+Cl; silicic, rich in Si+Al; and carbonatitic, rich in Ca+Mg+Fe [1, 3]. We used the carbonatitic end-member to represent fluid from a subducting slab reacting with an excess of peridotite + some saline fluid in the host environment. During simultaneous fluid mixing and reaction with the host rock, the logfO2 increased by about 1.6 units, and the pH increased by 0.7 units. The final minerals were olivine, garnet and diamond. The Mg# of olivine decreased from 0.92 to 0.85. Garnet precipitated at an early stage, and its Mg# also decreased with reaction progress, in agreement with the solid inclusions in the Panda diamonds. Phlogopite precipitated as an intermediate mineral and then disappeared. The aqueous Ca, Mg, Fe, Si and Al concentrations all increased, while Na, K, and Cl concentrations decreased during the reaction, consistent with trends in the fluid inclusion compositions. Our study demonstrates that fluids coming from subducting slabs could trigger mantle metasomatism, influence the compositions of sub-lithospherc cratonic mantle, precipitate diamonds, and change the oxygen fugacity and pH of the upper mantle fluids. [1] Tomlinson et al. EPSL (2006); [2] Sverjensky, DA et al., GCA (2014

  14. Pb evolution in the Martian mantle

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    Bellucci, J. J.; Nemchin, A. A.; Whitehouse, M. J.; Snape, J. F.; Bland, P.; Benedix, G. K.; Roszjar, J.

    2018-03-01

    The initial Pb compositions of one enriched shergottite, one intermediate shergottite, two depleted shergottites, and Nakhla have been measured by Secondary Ion Mass Spectrometry (SIMS). These values, in addition to data from previous studies using an identical analytical method performed on three enriched shergottites, ALH 84001, and Chassigny, are used to construct a unified and internally consistent model for the differentiation history of the Martian mantle and crystallization ages for Martian meteorites. The differentiation history of the shergottites and Nakhla/Chassigny are fundamentally different, which is in agreement with short-lived radiogenic isotope systematics. The initial Pb compositions of Nakhla/Chassigny are best explained by the late addition of a Pb-enriched component with a primitive, non-radiogenic composition. In contrast, the Pb isotopic compositions of the shergottite group indicate a relatively simple evolutionary history of the Martian mantle that can be modeled based on recent results from the Sm-Nd system. The shergottites have been linked to a single mantle differentiation event at 4504 Ma. Thus, the shergottite Pb isotopic model here reflects a two-stage history 1) pre-silicate differentiation (4504 Ma) and 2) post-silicate differentiation to the age of eruption (as determined by concordant radiogenic isochron ages). The μ-values (238U/204Pb) obtained for these two different stages of Pb growth are μ1 of 1.8 and a range of μ2 from 1.4-4.7, respectively. The μ1-value of 1.8 is in broad agreement with enstatite and ordinary chondrites and that proposed for proto Earth, suggesting this is the initial μ-value for inner Solar System bodies. When plotted against other source radiogenic isotopic variables (Sri, γ187Os, ε143Nd, and ε176Hf), the second stage mantle evolution range in observed mantle μ-values display excellent linear correlations (r2 > 0.85) and represent a spectrum of Martian mantle mixing-end members (depleted

  15. Relationship between stage II transport and number of chewing strokes as mastication progresses.

    Science.gov (United States)

    Yamashita, Shuichiro; Sugita, Daisuke; Matsuo, Koichiro

    2013-10-02

    As mastication progresses, little is known about the occurrence of the stage II transport (oro-pharyngeal bolus transport). This study aimed to investigate the relationship between stage II transport and bolus aggregation in the pharynx and the number of chewing strokes. Twenty-five clinical residents with natural dentitions were recruited. The subjects were asked to chew gummy jelly with their preferred rhythm and to swallow the bolus at their preferred timing. To investigate stage II transport and bolus aggregation in the pharynx, a transnasal endoscope was used. The number of chewing strokes was measured by electromyographic activity from the masseter muscle. The mean numbers of chewing strokes of pre-stage II transport and post-stage II transport were 29.8 and 8.1, respectively; the difference was significant (pchewing strokes of pre-stage II transport to that of post-stage II transport was 4.0 to 1.0. This study showed that stage II transport started at four-fifths of the way along the progress of mastication, and that stage II transport and bolus aggregation in the pharynx are related to the number of chewing strokes. © 2013. Published by Elsevier Inc. All rights reserved.

  16. Radiotherapy and chemotherapy in stages I and II non-Hodgkin's lymphomas of Waldeyer's ring

    International Nuclear Information System (INIS)

    Hayabuchi, Naofumi; Jingu, Kenichi; Miyoshi, Makoto; Akasi, Yuko; Masuda, Koji; Komiyama, Sotaro; Kikuchi, Masahiro.

    1990-01-01

    Sixty-four patients with stages I and II non-Hodgkin's lymphomas (NHL) involving Waldeyer's ring treated between 1970 and 1987 were reviewed. Patients with stage II NHL were subdivided into stage II1 (limited type) and stage II2 (advanced type) from the state of neck nodes. Stage II1 was defined as involvement of unilateral cervical nodes less than 4 cm in diameter as well as Waldeyer's ring involvement. Other stage II cases were classified as stage II2. All 17 patients with stage I HNL were treated with radiation therapy alone. Their diseases were well controlled, and none of them died of causes related to the lymphoma. Among 14 patients with stage II1 NHL, the 5-year survival rate for the 9 patients treated with radiation therapy alone was 87.5%. Until 1982, 19 of 21 patients with stage II2 NHL treated with radiation therapy alone or radiation therapy and adjuvant chemotherapy (VEMP or COPP) died within 5 years mainly of disseminated diseases. Since 1983, CHOP had been used as the main treatment as well as radiotherapy for the 12 stage II2 NHL patients. So far, only 3 of them relapsed and 2 of them died of causes related to the lymphoma. Only 1 of these 12 patients was T-cell lymphoma compared to 7 of 9 stage II2 patients before 1982. This suggests that patients with stage I and those with limited stage II can be safely treated with radiotherapy. Also aggressive chemotherapy as well as radiotherapy should be used for patients with advanced stage II HNL involving Waldeyer's ring. (author)

  17. Imatinib Mesylate in Treating Patients With Progressive, Refractory, or Recurrent Stage II or Stage III Testicular or Ovarian Cancer

    Science.gov (United States)

    2013-01-15

    Ovarian Dysgerminoma; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage II Malignant Testicular Germ Cell Tumor; Stage II Ovarian Germ Cell Tumor; Stage III Malignant Testicular Germ Cell Tumor; Stage III Ovarian Germ Cell Tumor; Testicular Seminoma

  18. Adjuvant Chemotherapy for Stage II Colon Cancer: A Clinical Dilemma.

    Science.gov (United States)

    Kannarkatt, Joseph; Joseph, Joe; Kurniali, Peter C; Al-Janadi, Anas; Hrinczenko, Borys

    2017-04-01

    The decision to treat a patient with stage II colon cancer with adjuvant chemotherapy can be challenging. Although the benefit of treatment is clear in most patients with stage III disease, the decision to provide chemotherapy after surgical resection in stage II disease must be made on an individual basis. Several trials have demonstrated the small but absolute benefits of receiving adjuvant chemotherapy for stage II colon cancer for disease-free survival and overall survival. In an attempt to better understand the role of chemotherapy, several studies were performed that identified high-risk characteristics that can be used prognostically and predictively to aid in the clinical decision making process. ASCO, the National Comprehensive Cancer Network, and the European Society of Medical Oncology have published guidelines describing these high-risk characteristics. Since then, several other molecular markers have emerged that may offer more information on a given patient's risk for recurrence. The decision to treat a patient with stage II colon cancer must be made on an individual basis, considering the risks and benefits of treatment. In this short review, we will present the available evidence and offer possible directions for future study.

  19. Eutectic melting temperature of the lowermost Earth's mantle

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    Andrault, D.; Lo Nigro, G.; Bolfan-Casanova, N.; Bouhifd, M.; Garbarino, G.; Mezouar, M.

    2009-12-01

    Partial melting of the Earth's deep mantle probably occurred at different stages of its formation as a consequence of meteoritic impacts and seismology suggests that it even continues today at the core-mantle boundary. Melts are important because they dominate the chemical evolution of the different Earth's reservoirs and more generally the dynamics of the whole planet. Unfortunately, the most critical parameter, that is the temperature profile inside the deep Earth, remains poorly constrained accross the planet history. Experimental investigations of the melting properties of materials representative of the deep Earth at relevant P-T conditions can provide anchor points to refine past and present temperature profiles and consequently determine the degree of melting at the different geological periods. Previous works report melting relations in the uppermost lower mantle region, using the multi-anvil press [1,2]. On the other hand, the pyrolite solidus was determined up to 65 GPa using optical observations in the laser-heated diamond anvil cell (LH-DAC) [3]. Finally, the melting temperature of (Mg,Fe)2SiO4 olivine is documented at core-mantle boundary (CMB) conditions by shock wave experiments [4]. Solely based on these reports, experimental data remain too sparse to draw a definite melting curve for the lower mantle in the relevant 25-135 GPa pressure range. We reinvestigated melting properties of lower mantle materials by means of in-situ angle dispersive X-ray diffraction measurements in the LH-DAC at the ESRF [5]. Experiments were performed in an extended P-T range for two starting materials: forsterite and a glass with chondrite composition. In both cases, the aim was to determine the onset of melting, and thus the eutectic melting temperatures as a function of pressure. Melting was evidenced from drastic changes of diffraction peak shape on the image plate, major changes in diffraction intensities in the integrated pattern, disappearance of diffraction rings

  20. Contemporary management of stage I and II seminoma.

    Science.gov (United States)

    Chung, Peter; Warde, Padraig

    2013-10-01

    Seminoma represents about 60 % of all testicular germ cell tumors. At presentation about 80 % of patients have stage I and about 15 % have stage II disease. The last three decades have seen a substantial change in the philosophy of management with the success of surveillance as a strategy to minimize unnecessary treatment, recognition of the late effects of radiation therapy, and the success of cisplatin-based chemotherapy as curative treatment either in the first-line or salvage setting. Overall, in stage I disease where 80-85 % are cured with orchiectomy alone, efforts now are directed at reducing the burden of the disease and its diagnosis on patients with increasing utilization of surveillance and decreased employment of adjuvant therapy. For stage II disease, balancing the relative toxicities of radiation and chemotherapy while avoiding the use of multimodality therapy due to the additive long-term toxicity has become the priority.

  1. Stage II Seminoma

    International Nuclear Information System (INIS)

    Sagerman, R.H.; Kotlove, D.J.; Regine, W.; Chung, C.T.; King, G.A.; Dalai, P.S.

    1988-01-01

    Between 1966 and 1985, 32 patients with stage II (21 A,11 B) testicular seminoma were treated with postorchiectomy irradiation to the retroperitoneal and ipsilateral iliac nodes; 28 received elective mediastinal-supraclavicular irradiation. The median follow-up was 8 1/2 years; 29 patients were followed up for over 3 years and 24 for over 5 years. Twenty-eight patients remain alive and well and four have die, two of a second primary cancer. Two patients developed recurrent seminoma in the mediastinum; these patients showed a variant lymphangiographic pattern. Both remain well after further irradiation or irradiation plus chemotherapy. A third patient developed nonseminomatous ''recurrence'' in the radiation field and is well after chemotherapy

  2. Carcinoma of the uterine cervix stage IB and early stage II. Prognostic value of the histological tumor regression after initial brachytherapy

    International Nuclear Information System (INIS)

    Calais, G.; Le Floch, O.; Chauvet, B.; Reynaud-Bougnoux, A.; Bougnoux, P.

    1989-01-01

    In our center limited centro pelvic invasive carcinomas of the uterine cervix (less than 4 cm) are treated with brachytherapy and surgery. With these therapeutic modalities no residual carcinoma was observed for 80% of the patients. The purpose of this study was to evaluate our results with this treatment, and to evaluate the prognostic value of the pathological status of the cervix. From 1976 to 1987 we have treated 115 patients with these modalities. Staging system used was the FIGO classification modified for Stage II (divided in early Stage II and late Stage II). Patients were Stage IB (70 cases) and early Stage II (45 cases); 60 Gy were delivered with utero vaginal brachytherapy before any treatment. Six weeks later a radical hysterectomy with pelvic lymphadenectomy was performed. Twenty-one patients with positive nodes received a pelvic radiotherapy (45 to 55 Gy). Local control rate was 97% (100% for Stage IB and 93% for early Stage II). Uncorrected 10-year actuarial survival rate was 96% for Stage IB and 80% for early Stage II patients. No treatment failure was observed for Stage IB patients. Ninety-two patients (80%) had no residual carcinoma in the cervix (group 1) and 23 patients (20%) had a residual tumor (group 2). The sterilization rate of the cervix was 87% for Stage IB tumors versus 69% for early Stage II, and was 82% for N- patients versus 68% for N+ patients. Ten year actuarial survival rate was 92% for group 1 and 78% for group 2 (p = 0, 1). Grade 3 complications rate was 6%. We conclude that brachytherapy + surgery is a safe treatment for limited centro pelvic carcinomas of the uterine cervix (especially Stage IB) and that pathological status of the cervix after brachytherapy is not a prognostic factor

  3. Spin Transition in the Lower Mantle: Deep Learning and Pattern Recognition of Superplumes from the Mid-mantle and Mid-mantle Slab Stagnation

    Science.gov (United States)

    Yuen, D. A.; Shahnas, M. H.; De Hoop, M. V.; Pysklywec, R.

    2016-12-01

    The broad, slow seismic anomalies under Africa and Pacific cannot be explained without ambiguity. There is no well-established theory to explain the fast structures prevalent globally in seismic tomographic images that are commonly accepted to be the remnants of fossil slabs at different depths in the mantle. The spin transition from high spin to low spin in iron in ferropericlase and perovskite, two major constituents of the lower mantle can significantly impact their physical properties. We employ high resolution 2D-axisymmetric and 3D-spherical control volume models to reconcile the influence of the spin transition-induced anomalies in density, thermal expansivity, and bulk modulus in ferropericlase and perovskite on mantle dynamics. The model results reveal that the spin transition effects increase the mixing in the lower regions of mantle. Depending on the changes of bulk modulus associated with the spin transition, these effects may also cause both stagnation of slabs and rising plumes at mid-mantle depths ( 1600 km). The stagnation may be followed by downward or upward penetration of cold or hot mantle material, respectively, through an avalanche process. The size of these mid-mantle plumes reaches 1500 km across with a radial velocity reaching 20 cm/yr near the seismic transition zone and plume heads exceeding 2500 km across. We will employ a deep-learning algorithm to formulate this challenge as a classification problem where modelling/computation aids in the learning stage for detecting the particular patterns.The parameters based on which the convection models are developed are poorly constrained. There are uncertainties in initial conditions, heterogeneities and boundary conditions in the simulations, which are nonlinear. Thus it is difficult to reconstruct the past configuration over long time scales. In order to extract information and better understand the parameters in mantle convection, we employ deep learning algorithm to search for different

  4. Tracing changes in mantle and crustal influences in individual cone-building stages at Mt. Shasta using U-Th and Sr isotopes

    Science.gov (United States)

    Wende, Allison M.; Johnson, Clark M.; Beard, Brian L.

    2015-10-01

    230Th-excess is rare in most arc lavas, but common in the Cascades, yet the origin of such excesses remains unclear. At Mt. Shasta, age-corrected (230Th/232Th) and (238U/232Th) activity ratios range from 1.108 to 1.290 and from 0.987 to 1.309 (27.3% 230Th-excess to 6.1% 238U-excess), respectively. Although small degrees of zircon crystallization (ancestral cone (Sand Flat) was followed by four cone-building stages, three of which lie in the age range of U-series geochronology. Lavas within individual eruptive stages have relatively constant (230Th/232Th)0 ratios that are interpreted to reflect specific mixtures of mantle (m) and lower crustal (lc) melts that are characteristic of a specific stage (Mm:lc). High (230Th/232Th)0 ratios identify higher proportions of lower crust in the Misery Hill stage (Mm:lc = ∼ 85 : 15), whereas low (230Th/232Th)0 ratios reflect the more mantle-like composition of the Shastina lavas (Mm:lc = ∼ 95 : 5); in the case of Shastina lavas, very low 87Sr/86Sr ratios, down to 0.7029, support a substantial mantle contribution. Changes in (230Th/232Th)0 ratios correlate with eruptive volume, where the most voluminous stage (Misery Hill) is inferred to have the largest proportion of crustal melt and highest (230Th/232Th)0 ratios. Variable (230Th/238U)0 ratios within, and between, eruptive groups likely reflect a combination of residence time in the lower crust and differential assimilation of bulk, non-garnet-bearing crust that had (230Th/238U) = 1. The volume-(230Th/232Th)0 relations are accompanied by correlations with 87Sr/86Sr ratios, where the most radiogenic Sr is associated with the largest eruptive volumes, indicating that the largest magmatic episodes produced the largest amount of lower crustal interaction. The new U-Th and Sr isotope measurements of this study, along with U-series data for other Cascade centers suggest that interaction with the lower crust exerts greater control on Cascade magma chemistry than previously

  5. The origin of volatiles in the Earth's mantle

    Science.gov (United States)

    Hier-Majumder, Saswata; Hirschmann, Marc M.

    2017-08-01

    The Earth's deep interior contains significant reservoirs of volatiles such as H, C, and N. Due to the incompatible nature of these volatile species, it has been difficult to reconcile their storage in the residual mantle immediately following crystallization of the terrestrial magma ocean (MO). As the magma ocean freezes, it is commonly assumed that very small amounts of melt are retained in the residual mantle, limiting the trapped volatile concentration in the primordial mantle. In this article, we show that inefficient melt drainage out of the freezing front can retain large amounts of volatiles hosted in the trapped melt in the residual mantle while creating a thick early atmosphere. Using a two-phase flow model, we demonstrate that compaction within the moving freezing front is inefficient over time scales characteristic of magma ocean solidification. We employ a scaling relation between the trapped melt fraction, the rate of compaction, and the rate of freezing in our magma ocean evolution model. For cosmochemically plausible fractions of volatiles delivered during the later stages of accretion, our calculations suggest that up to 77% of total H2O and 12% of CO2 could have been trapped in the mantle during magma ocean crystallization. The assumption of a constant trapped melt fraction underestimates the mass of volatiles in the residual mantle by more than an order of magnitude.Plain Language SummaryThe Earth's deep interior contains substantial amounts of volatile elements like C, H, and N. How these elements got sequestered in the Earth's interior has long been a topic of debate. It is generally assumed that most of these elements escaped the interior of the Earth during the first few hundred thousand years to create a primitive atmosphere, leaving the mantle reservoir nearly empty. In this work, we show that the key to this paradox involves the very early stages of crystallization of the mantle from a global magma ocean. Using numerical models, we show

  6. SOX9 Expression Predicts Relapse of Stage II Colon Cancer Patients

    DEFF Research Database (Denmark)

    Espersen, Maiken Lise Marcker; Linnemann, Dorte; Christensen, Ib Jarle

    2016-01-01

    The aim of this study was to investigate if the protein expression of Sex-determining region y-box 9 (SOX9) in primary tumors could predict relapse of stage II colon cancer patients.144 patients with stage II primary colon cancer were retrospectively enrolledin the study. SOX9 expression...

  7. Subdiaphragmatic stage I and II Hodgkin's disease - long-term follow-up and prognostic factors

    International Nuclear Information System (INIS)

    Liao Zhongxing; Ha, Chul S.; Fuller, Lillian M.; Hagemeister, Fredrick B.; Cabanillas, Fernando; Tucker, Susan L.; Hess, Mark A.; Cox, James D.

    1997-01-01

    statistically significant negative pretreatment prognostic factors for disease-free survival. Only B symptoms and decreased albumin level predicted worse outcome in both overall and disease-free survivals. Age, histology, and hemoglobin level were three independent risk factors for overall survival on multivariate analysis. An analysis of the pattern of failure revealed that majority of the patients with Stage II disease who did not receive mantle radiation failed in the supradiaphragmatic area. Late complications of radiation were infrequent. Conclusions: Long term follow up of this group of patients revealed similar overall and disease free long term survival as would be expected from supradiaphragmatic Hodgkin's disease. For patients with stage II disease, it is anticipated that supradiaphragmatic radiation therapy would improve the disease free survival

  8. Proton Beam Therapy of Stage II and III Non–Small-Cell Lung Cancer

    International Nuclear Information System (INIS)

    Nakayama, Hidetsugu; Satoh, Hiroaki; Sugahara, Shinji; Kurishima, Koichi; Tsuboi, Koji; Sakurai, Hideyuki; Ishikawa, Shigemi; Tokuuye, Koichi

    2011-01-01

    Purpose: The present retrospective study assessed the role of proton beam therapy (PBT) in the treatment of patients with Stage II or III non–small-cell lung cancer who were inoperable or ineligible for chemotherapy because of co-existing disease or refusal. Patients and Methods: Between November 2001 and July 2008, PBT was given to 35 patients (5 patients with Stage II, 12 with Stage IIIA, and 18 with Stage IIIB) whose median age was 70.3 years (range, 47.4–85.4). The median proton dose given was 78.3 Gy (range, 67.1–91.3) (relative biologic effectiveness). Results: Local progression-free survival for Stage II-III patients was 93.3% at 1 year and 65.9% at 2 years during a median observation period of 16.9 months. Four patients (11.4%) developed local recurrence, 13 (37.1%) developed regional recurrence, and 7 (20.0%) developed distant metastases. The progression-free survival rate for Stage II-III patients was 59.6% at 1 year and 29.2% at 2 years. The overall survival rate of Stage II-III patients was 81.8% at 1 year and 58.9% at 2 years. Grade 3 or greater toxicity was not observed. A total of 15 patients (42.9%) developed Grade 1 and 6 (17.1%) Grade 2 toxicity. Conclusion: PBT for Stage II-III non–small-cell lung cancer without chemotherapy resulted in good local control and low toxicity. PBT has a definite role in the treatment of patients with Stage II-III non–small-cell lung cancer who are unsuitable for surgery or chemotherapy.

  9. Proton Beam Therapy of Stage II and III Non-Small-Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Hidetsugu, E-mail: hnakayam@tokyo-med.ac.jp [Proton Medical Research Center, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, Tokyo Medical University, Shinjuku, Tokyo (Japan); Satoh, Hiroaki [Department of Respiratory Medicine, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki (Japan); Sugahara, Shinji [Proton Medical Research Center, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, Tokyo Medical University, Shinjuku, Tokyo (Japan); Kurishima, Koichi [Department of Respiratory Medicine, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki (Japan); Tsuboi, Koji; Sakurai, Hideyuki [Proton Medical Research Center, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki (Japan); Ishikawa, Shigemi [Department of Thoracic Surgery, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki (Japan); Tokuuye, Koichi [Proton Medical Research Center, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, Tokyo Medical University, Shinjuku, Tokyo (Japan)

    2011-11-15

    Purpose: The present retrospective study assessed the role of proton beam therapy (PBT) in the treatment of patients with Stage II or III non-small-cell lung cancer who were inoperable or ineligible for chemotherapy because of co-existing disease or refusal. Patients and Methods: Between November 2001 and July 2008, PBT was given to 35 patients (5 patients with Stage II, 12 with Stage IIIA, and 18 with Stage IIIB) whose median age was 70.3 years (range, 47.4-85.4). The median proton dose given was 78.3 Gy (range, 67.1-91.3) (relative biologic effectiveness). Results: Local progression-free survival for Stage II-III patients was 93.3% at 1 year and 65.9% at 2 years during a median observation period of 16.9 months. Four patients (11.4%) developed local recurrence, 13 (37.1%) developed regional recurrence, and 7 (20.0%) developed distant metastases. The progression-free survival rate for Stage II-III patients was 59.6% at 1 year and 29.2% at 2 years. The overall survival rate of Stage II-III patients was 81.8% at 1 year and 58.9% at 2 years. Grade 3 or greater toxicity was not observed. A total of 15 patients (42.9%) developed Grade 1 and 6 (17.1%) Grade 2 toxicity. Conclusion: PBT for Stage II-III non-small-cell lung cancer without chemotherapy resulted in good local control and low toxicity. PBT has a definite role in the treatment of patients with Stage II-III non-small-cell lung cancer who are unsuitable for surgery or chemotherapy.

  10. Chemotherapy Toxicity On Quality of Life in Older Patients With Stage I, Stage II, Stage III, or Stage IV Ovarian Epithelial, Primary Peritoneal Cavity, or Fallopian Tube Cancer

    Science.gov (United States)

    2017-05-03

    Stage I Ovarian Cancer; Stage IA Fallopian Tube Cancer; Stage IB Fallopian Tube Cancer; Stage IC Fallopian Tube Cancer; Stage II Ovarian Cancer; Stage IIA Fallopian Tube Cancer; Stage IIB Fallopian Tube Cancer; Stage IIC Fallopian Tube Cancer; Stage III Ovarian Cancer; Stage III Primary Peritoneal Cancer; Stage IIIA Fallopian Tube Cancer; Stage IIIB Fallopian Tube Cancer; Stage IIIC Fallopian Tube Cancer; Stage IV Fallopian Tube Cancer; Stage IV Ovarian Cancer; Stage IV Primary Peritoneal Cancer

  11. Linking lowermost mantle structure, core-mantle boundary heat flux and mantle plume formation

    Science.gov (United States)

    Li, Mingming; Zhong, Shijie; Olson, Peter

    2018-04-01

    The dynamics of Earth's lowermost mantle exert significant control on the formation of mantle plumes and the core-mantle boundary (CMB) heat flux. However, it is not clear if and how the variation of CMB heat flux and mantle plume activity are related. Here, we perform geodynamic model experiments that show how temporal variations in CMB heat flux and pulses of mantle plumes are related to morphologic changes of the thermochemical piles of large-scale compositional heterogeneities in Earth's lowermost mantle, represented by the large low shear velocity provinces (LLSVPs). We find good correlation between the morphologic changes of the thermochemical piles and the time variation of CMB heat flux. The morphology of the thermochemical piles is significantly altered during the initiation and ascent of strong mantle plumes, and the changes in pile morphology cause variations in the local and the total CMB heat flux. Our modeling results indicate that plume-induced episodic variations of CMB heat flux link geomagnetic superchrons to pulses of surface volcanism, although the relative timing of these two phenomena remains problematic. We also find that the density distribution in thermochemical piles is heterogeneous, and that the piles are denser on average than the surrounding mantle when both thermal and chemical effects are included.

  12. Adjuvant Therapy for Stage II Colorectal Cancer: Who and with What?

    Science.gov (United States)

    Chung, Ki-Young Y; Kelsen, David

    2006-06-01

    The role of adjuvant chemotherapy for patients with stage II colon adenocarcinoma remains controversial. The high surgical cure rate for patients with "low-risk" stage II colon cancer, ranging from 75% to 80%, and the available clinical trials and meta-analyses provide conflicting recommendations for or against adjuvant chemotherapy for this group of patients. For fit "high-risk" stage II patients with clinical obstruction or perforation at presentation, in which the 5-year survival rate is 60% to 70%, there is little controversy, as these patients are routinely treated with adjuvant chemotherapy. Other potential high-risk factors, including high histologic grade, microsatellite instability, and loss of 18q, have yet to be validated in prospective trials. Patients with fewer than 12 regional lymph nodes identified in the surgical specimen have a statistically unclear risk of lymph node involvement. These patients may have stage III disease and should receive adjuvant therapy. The decision to use adjuvant chemotherapy to treat low-risk stage II colon cancer patients (no obstruction or perforation) should be an informed decision weighing the magnitude of a net 2% to 5% survival benefit, a 0.5% to 1.0% risk of mortality with chemotherapy in addition to 6 months of chemotherapy-related toxicities, other coexisting patient morbidities, and the anticipated life expectancy of each patient. As adjuvant chemotherapy is therapy addressing local or metastatic microscopic disease, and the effectiveness of systemic and biologically targeted therapy for advanced macroscopic colon cancer continues to improve rapidly, it remains to be determined by clinical trials whether therapies including newer agents such as cetuximab and bevacizumab administered in the adjuvant setting may affect survival for stage II cancer patients.

  13. Birch's Mantle

    Science.gov (United States)

    Anderson, D. L.

    2002-12-01

    Francis Birch's 1952 paper started the sciences of mineral physics and physics of the Earth's interior. Birch stressed the importance of pressure, compressive strain and volume in mantle physics. Although this may seem to be an obvious lesson many modern paradoxes in the internal constitution of the Earth and mantle dynamics can be traced to a lack of appreciation for the role of compression. The effect of pressure on thermal properties such as expansivity can gravitational stratify the Earth irreversibly during accretion and can keep it chemically stratified. The widespread use of the Boussinesq approximation in mantle geodynamics is the antithesis of Birchian physics. Birch pointed out that eclogite was likely to be an important component of the upper mantle. Plate tectonic recycling and the bouyancy of oceanic crust at midmantle depths gives credence to this suggestion. Although peridotite dominates the upper mantle, variations in eclogite-content may be responsible for melting- or fertility-spots. Birch called attention to the Repetti Discontinuity near 900 km depth as an important geodynamic boundary. This may be the chemical interface between the upper and lower mantles. Recent work in geodynamics and seismology has confirmed the importance of this region of the mantle as a possible barrier. Birch regarded the transition region (TR ; 400 to 1000 km ) as the key to many problems in Earth sciences. The TR contains two major discontinuities ( near 410 and 650 km ) and their depths are a good mantle thermometer which is now being exploited to suggest that much of plate tectonics is confined to the upper mantle ( in Birch's terminology, the mantle above 1000 km depth ). The lower mantle is homogeneous and different from the upper mantle. Density and seismic velocity are very insensitive to temperature there, consistent with tomography. A final key to the operation of the mantle is Birch's suggestion that radioactivities were stripped out of the deeper parts of

  14. A mid-term follow-up of Koutsogiannis’ osteotomy in adult-acquired flatfoot stage II and “early stage III”

    Directory of Open Access Journals (Sweden)

    Arvinius Camilla

    2017-01-01

    Full Text Available Introduction: Koutsogiannis’ osteotomy has been widely described to treat adult-acquired flatfoot. However, few articles describe its midterm follow-up. Our aim was to study clinical and radiological outcomes at least one year after surgery and to analyze whether a combined procedure on the medial soft tissue affected these outcomes. Methods: We performed a retrospective study of 30 feet of patients who underwent a Koutsogiannis’ osteotomy due to adult-acquired flatfoot stage II and “early stage III”: a stage III acquired flatfoot without any important structural deformities. The parameters studied were additional medial soft tissue procedures, clinical outcome through the American Orthopaedic Foot and Ankle Society (AOFAS ankle and midfoot score as well as complications and radiological measurements. Results: Sixteen cases were “early stage III” and 14 stage II. Thirteen patients underwent an associated posterior tibial tendon (PTT revision: in three cases an end-to-end suture was possible, seven cases needed a FDL transposition, and three underwent synovectomy. Statistically significant improvement was found in the AOFAS score although no significant changes were seen radiologically. No additional benefit was found with the revision of the posterior tibial tendon. As to clinical and radiological results, no differences were found between stage II and “early stage III”. Five cases presented a mild dysesthesia but only one patient needed neurolysis. Conclusions: We consider the Koutsogiannis’ osteotomy to be a safe and effective procedure to reduce pain in patients with stage II and “early stage III” adult-acquired flatfoot.

  15. Implementation of the II. Stage decommissioning of A1 NPP

    International Nuclear Information System (INIS)

    Ficher, T.

    2015-01-01

    Presentation is focused on the implementation of the II. stage decommissioning of A1 NPP. Introductory part focuses on brief characteristics of the power plant with a history of operation, basic technical parameters and actions that were made after operation. The next section describes the basic schedule for decommissioning, structure of management and implementation of the II. stage decommissioning of the A1 NPP and objectives of the individual stages. The last and largest part of the presentation is devoted to detailed description of the II. stage decommissioning of the A1 NPP, its individual tasks and verbal and visual description of the activities that were performed. Presented is decommissioning of the technology and construction of external objects NPP A1 including storage tanks for liquid RAW, next are presented activities carried out in the Main Production Unit - decommissioning of non-operating technologies in various places/rooms, management of waste arising from these activities, treatment of case of A1 long-term spent fuel storage and long-term spent fuel storage. The subsequent section is devoted to the management and handling of contaminated soil, concrete and construction waste, including management of VLLW. (authors)

  16. Postoperative radiotherapy for stage I/II seminoma: results for 212 patients

    International Nuclear Information System (INIS)

    Bauman, Glenn S.; Venkatesan, Varagur M.; Ago, C. Tetteh; Radwan, John S.; Dar, A. Rashid; Winquist, Eric W.

    1998-01-01

    Purpose: A retrospective review of patients with Stage I and II seminoma treated at a regional cancer center was performed to assess the long term efficacy and toxicity associated with post operative radiotherapy. Methods and Materials: Between 1950 and 1995, 212 patients seen at the London Regional Cancer Centre received adjuvant radiotherapy following orchiectomy for Stage I (169) and II (43) seminoma. Median follow-up for the group was 7.5 years. Results: Progression free, cause specific, and overall survival were 95%, 98%, and 95% at 5 years, and 94%, 98%, and 94% at 10 years respectively. An increased risk of failure was noted among patients with bulky Stage II disease. No other prognostic factors for relapse were identified. Late toxicity was uncommon with only 12/212 (6%) developing any late GI toxicity potentially attributable to radiotherapy. The incidence of second malignancies (excluding second testicular tumors) was 6/212 (actuarial:1%, 1%, 6% at 5,10,15 years respectively). There was a trend toward increased acute complications for patients treated with larger volumes of radiation. No prognostic factors associated with increased risk of late toxicity or second malignancy were identified, likely a consequence of the small number of these events. Conclusion: Survival and toxicity were comparable to that reported in the literature. Post-operative radiotherapy remains a safe and efficacious adjuvant treatment for Stage I and early Stage II seminoma

  17. Second Stage (S-II) Arrives at Marshall Space Flight Center For Testing

    Science.gov (United States)

    2004-01-01

    The business end of a Second Stage (S-II) slowly emerges from the shipping container as workers prepare to transport the Saturn V component to the testing facility at MSFC. The Second Stage (S-II) underwent vibration and engine firing tests. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  18. Two technicians apply insulation to S-II second stage

    Science.gov (United States)

    1964-01-01

    Two technicians apply insulation to the outer surface of the S-II second stage booster for the Saturn V moon rocket. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  19. EFFECTS OF STELLAR FLUX ON TIDALLY LOCKED TERRESTRIAL PLANETS: DEGREE-1 MANTLE CONVECTION AND LOCAL MAGMA PONDS

    International Nuclear Information System (INIS)

    Gelman, S. E.; Elkins-Tanton, L. T.; Seager, S.

    2011-01-01

    We model the geodynamical evolution of super-Earth exoplanets in synchronous rotation about their star. While neglecting the effects of a potential atmosphere, we explore the parameter spaces of both the Rayleigh number and intensity of incoming stellar flux, and identify two main stages of mantle convection evolution. The first is a transient stage in which a lithospheric temperature and thickness dichotomy emerges between the substellar and the antistellar hemispheres, while the style of mantle convection is dictated by the Rayleigh number. The second stage is the development of degree-1 mantle convection. Depending on mantle properties, the timescale of onset of this second stage of mantle evolution varies from order 1 to 100 billion years of simulated planetary evolution. Planets with higher Rayleigh numbers (due to, for instance, larger planetary radii than the Earth) and planets whose incoming stellar flux is high (likely for most detectable exoplanets) will develop degree-1 mantle convection most quickly, on the order of 1 billion years, which is within the age of many planetary systems. Surface temperatures range from 220 K to 830 K, implying the possibility of liquid water in some regions near the surface. These results are discussed in the context of stable molten magma ponds on hotter planets, and the habitability of super-Earths which may lie outside the Habitable Zone.

  20. Extended Cancer Education for Longer-Term Survivors in Primary Care for Patients With Stage I-II Breast or Prostate Cancer or Stage I-III Colorectal Cancer

    Science.gov (United States)

    2017-11-15

    Stage I Breast Cancer; Stage I Colorectal Cancer AJCC v6 and v7; Stage I Prostate Cancer; Stage IA Breast Cancer; Stage IB Breast Cancer; Stage II Breast Cancer; Stage II Colorectal Cancer AJCC v7; Stage II Prostate Cancer; Stage IIA Breast Cancer; Stage IIA Colorectal Cancer AJCC v7; Stage IIA Prostate Cancer; Stage IIB Breast Cancer; Stage IIB Colorectal Cancer AJCC v7; Stage IIB Prostate Cancer; Stage IIC Colorectal Cancer AJCC v7; Stage III Colorectal Cancer AJCC v7; Stage IIIA Colorectal Cancer AJCC v7; Stage IIIB Colorectal Cancer AJCC v7; Stage IIIC Colorectal Cancer AJCC v7

  1. Patterns of Pelvic Radiotherapy in Patients with Stage II/III Rectal Cancer

    International Nuclear Information System (INIS)

    Fitzgerald, T. L.; Zervos, E.; Wong, J. H.; Fitzgerald, T. L.; Zervos, E.; Wong, J. H.; Fitzgerald, T. L.; Zervos, E.; Wong, J. H.

    2013-01-01

    High-level evidence supports adjuvant radiotherapy for rectal cancer. We examined the influence of socio demographic factors on patterns of adjuvant radiotherapy for resected Stage II/III rectal cancer. Methods. Patients undergoing surgical resection for stage II/III rectal cancer were identified in SEER registry. Results. A total of 21,683 patients were identified. Majority of patients were male (58.8%), white (83%), and with stage III (54.9%) and received radiotherapy (66%). On univariate analysis, male gender, stage III, younger age, year of diagnosis, and higher socioeconomic status (SES) were associated with radiotherapy. Radiotherapy was delivered in 84.4% of patients <50; however, only 32.8% of those are >80 years. Logistic regression demonstrated a significant increase in the use of radiotherapy in younger patients who are 50 (OR, 10.3), with stage III (OR, 1.21), males (OR, 1.18), and with higher SES. Conclusions. There is a failure to conform to standard adjuvant radiotherapy in one-third of patients, and this is associated with older age, stage II, area-level of socioeconomic deprivation, and female sex.

  2. Noble Gas Isotope Evidence for Mantle Volatiles in the Cu-Mo Porphyry and Main Stage Polymetallic Veins at Butte, Montana

    Science.gov (United States)

    Hofstra, A. H.; Rusk, B. G.; Manning, A. H.; Hunt, A. G.; Landis, G. P.

    2017-12-01

    Recent studies suggest that volatiles released from mafic intrusions may be important sources of heat, sulfur, and metals in porphyry Cu-Mo-Au and epithermal Au-Ag deposits associated with intermediate to silicic stocks. The huge Cu-Mo porphyry and Main Stage polymetallic vein deposits at Butte are well suited to test this hypothesis because there is no geologic or isotopic evidence of basaltic intrusions in the mine or drill holes. The Butte porphyry-vein system is associated with quartz monzonite stocks and dikes within the southwest part of the Late Cretaceous Boulder batholith. The Boulder batholith was emplaced into Mesoproterozoic to Mesozoic sedimentary rocks and Late Cretaceous volcanic rocks. The Boulder batholith and Butte intrusions have Sri and eNd values indicative of crustal contamination. Eu and Ce anomalies in zircon from Butte intrusions provide evidence of oxidation due to magma degassing. To ascertain the source of volatiles in this system, 11 samples from the Cu-Mo porphyry and 16 from Main Stage veins were selected. The isotopic composition of Ar, Ne, and He extracted from fluid inclusions in quartz, magnetite, pyrite, chalcopyrite, sphalerite, galena, enargite, and covellite were determined. Helium isotopes exceed blank levels in all samples and Ne and Ar in some samples. On a 38Ar/36Ar vs. 40Ar/36Ar diagram, data plot near air. On a 20Ne/22Ne vs. 21Ne/22Ne diagram, data extend from air along the trajectories of OIB and MORB. On a 36Ar/4He vs. 3He/4He RA diagram, data extend from crust toward the air-mantle mixing line. The maximum 3He/4He RA values in the Cu-Mo porphyry (2.86) and Main Stage veins (3.46) are from pyrite and these values correspond to 36 and 43 % mantle helium. The Ne and He results show that fluid inclusions contain volatiles discharged from mantle magmas and that these volatiles were diluted by groundwater containing He derived from country rocks. Despite the lack of mafic intrusions in the Butte magmatic center, noble gas

  3. Brachytherapy for elderly patients with stage II tongue cancer

    International Nuclear Information System (INIS)

    Kimura, Tomoki; Hirokawa, Yutaka; Fujita, Minoru; Murakami, Yuji; Kenjo, Masahiro; Kaneyasu, Yuko; Ito, Katsuhide

    2003-01-01

    In treatment choices of stage II (T2N0M0) tongue cancer, brachytherapy is less invasive and superior in function preservation, therefore its role is more important in elderly patients. The aim of this study was to evaluate treatment results and morbidity of brachytherapy for elderly patients with stage II tongue cancer. Between 1980 and 2001, 198 patients with stage II tongue cancer were treated with brachytherapy at Hiroshima University Hospital. Patient ages ranged from 21 to 89 years old (median: 62 years old). Patients were divided into three groups as follows: 119 patients younger than 65 years old (Non-Elderly group), 53 patients between 65 and 75 years old (Junior Elderly group), and 26 patients 75 years or older (Senior Elderly group). Radiotherapy was performed in 101 patients with brachytherapy alone, and in 97 patients with brachytherapy and external radiotherapy. Chemotherapy was also performed in 77 patients. Follow-up period ranged from 4 to 243 months (median: 55 months). The 5-year local control rate was 85% in the Non-Elderly group, 85% in the Junior Elderly group and 81% in the Senior Elderly group. There was no significant difference among these groups. The 5-year cause-specific survival rate was 85%, 81% and 70% respectively. The Senior Elderly group showed poorer cause-specific survival rate than the other two groups (p=0.03). There was also a tendency of higher incidence of neck metastasis and low salvage rate by neck dissection in the Senior Elderly group. Although the Senior Elderly group showed poorer cause-specific survival rate, the local control rate was similar to those of the other two groups. Brachytherapy is an effective treatment option for elderly patients with stage II tongue cancer. (author)

  4. Lenalidomide and Combination Chemotherapy (DA-EPOCH-R) in Treating Patients With MYC-Associated B-Cell Lymphomas

    Science.gov (United States)

    2017-09-28

    Adult Grade III Lymphomatoid Granulomatosis; B-cell Chronic Lymphocytic Leukemia; Contiguous Stage II Adult Diffuse Large Cell Lymphoma; Contiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Contiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Contiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Contiguous Stage II Grade 1 Follicular Lymphoma; Contiguous Stage II Grade 2 Follicular Lymphoma; Contiguous Stage II Grade 3 Follicular Lymphoma; Contiguous Stage II Mantle Cell Lymphoma; Contiguous Stage II Marginal Zone Lymphoma; Contiguous Stage II Small Lymphocytic Lymphoma; Cutaneous B-cell Non-Hodgkin Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Intraocular Lymphoma; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Adult Diffuse Large Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Noncontiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Mantle Cell Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Progressive Hairy Cell Leukemia, Initial Treatment; Small Intestine Lymphoma; Splenic Marginal Zone Lymphoma; Stage 0 Chronic Lymphocytic Leukemia; Stage I Adult Diffuse Large Cell Lymphoma; Stage I Adult Diffuse Mixed Cell Lymphoma; Stage I Adult Diffuse Small Cleaved Cell Lymphoma; Stage I Adult Hodgkin Lymphoma; Stage I Adult Immunoblastic Large Cell Lymphoma; Stage I Chronic Lymphocytic Leukemia; Stage I Grade 1 Follicular Lymphoma; Stage I Grade 2 Follicular Lymphoma; Stage I Grade 3 Follicular Lymphoma; Stage I Mantle Cell Lymphoma; Stage I Marginal Zone Lymphoma; Stage I Small Lymphocytic Lymphoma; Stage II Adult Hodgkin Lymphoma; Stage II Chronic Lymphocytic

  5. Seismic structure of the European upper mantle based on adjoint tomography

    Science.gov (United States)

    Zhu, Hejun; Bozdağ, Ebru; Tromp, Jeroen

    2015-04-01

    We use adjoint tomography to iteratively determine seismic models of the crust and upper mantle beneath the European continent and the North Atlantic Ocean. Three-component seismograms from 190 earthquakes recorded by 745 seismographic stations are employed in the inversion. Crustal model EPcrust combined with mantle model S362ANI comprise the 3-D starting model, EU00. Before the structural inversion, earthquake source parameters, for example, centroid moment tensors and locations, are reinverted based on global 3-D Green's functions and Fréchet derivatives. This study consists of three stages. In stage one, frequency-dependent phase differences between observed and simulated seismograms are used to constrain radially anisotropic wave speed variations. In stage two, frequency-dependent phase and amplitude measurements are combined to simultaneously constrain elastic wave speeds and anelastic attenuation. In these two stages, long-period surface waves and short-period body waves are combined to simultaneously constrain shallow and deep structures. In stage three, frequency-dependent phase and amplitude anomalies of three-component surface waves are used to simultaneously constrain radial and azimuthal anisotropy. After this three-stage inversion, we obtain a new seismic model of the European curst and upper mantle, named EU60. Improvements in misfits and histograms in both phase and amplitude help us to validate this three-stage inversion strategy. Long-wavelength elastic wave speed variations in model EU60 compare favourably with previous body- and surface wave tomographic models. Some hitherto unidentified features, such as the Adria microplate, naturally emerge from the smooth starting model. Subducting slabs, slab detachments, ancient suture zones, continental rifts and backarc basins are well resolved in model EU60. We find an anticorrelation between shear wave speed and anelastic attenuation at depths agreement with previous global attenuation studies

  6. Early mantle differentiation: constraint from 146Sm-142Nd systematics

    International Nuclear Information System (INIS)

    Caro, G.

    2005-07-01

    We present new ultra-high precision 142 Nd/ 144 Nd measurements of early Archaean rocks using the new generation thermal ionization mass spectrometer TRITON. Repeated measurements of the Ames Nd standard demonstrate that the 142 Nd/ 144 Nd ratio can be determined with external precision of 2 ppm (2s), allowing confident resolution of anomalies as small as 5 ppm. A major analytical improvement lies in the elimination of the double normalization procedure required to correct our former measurements from a secondary mass fractionation effect. Our new results indicate that metasediments, meta-basalts and orthogneisses from the 3.6 - 3.8 Ga West Greenland craton display positive 142 Nd anomalies ranging from 8 to 15 ppm. Using a simple two-stage model with initial e 143 Nd value of 1.9 ± 0.6 e-units, coupled 147 Sm- 143 Nd and 146 Sm- 142 Nd chronometry constrains mantle differentiation to 50 to 200 Ma after formation of the solar system. This chronological constraint is consistent with differentiation of the Earth's mantle during the late stage of crystallization of a magma ocean. We have developed a two-box model describing 142 Nd and 143 Nd isotopic evolution of depleted mantle during the subsequent evolution of the crust-mantle system. Our results indicate that early terrestrial proto-crust had a lifetime of ca. 500 Ma in order to produce the observed Nd isotope signature of Archaean rocks. In the context of this two box mantle-crust system, we model the evolution of isotopic and chemical heterogeneity of depleted mantle as a function of the mantle stirring time. Using the dispersion of 142 Nd/ 144 Nd and 143 Nd/ 144 Nd ratios observed in early Archaean rocks, we constrain the stirring time of early Earth's mantle to 100 - 150 Ma, a factor of 5 to 10 shorter than stirring time inferred from modern oceanic basalts. (author)

  7. Composition of the earth's upper mantle. II - Volatile trace elements in ultramafic xenoliths

    Science.gov (United States)

    Morgan, J. W.; Wandless, G. A.; Petrie, R. K.; Irving, A. J.

    1980-01-01

    Radiochemical neutron activation analysis was used to determine the nine volatile elements Ag, Bi, Cd, In, Sb, Se, Te, Tl, and Zn in 19 ultramafic rocks, consisting mainly of spinel and garnet lherzolites. A sheared garnet lherzolite, PHN 1611, may approximate undepleted mantle material and tends to have a higher volatile element content than the depleted mantle material represented by spinel lherzolites. Comparisons of continental basalts with PHN 1611 and of oceanic ridge basalts with spinel lherzolites show similar basalt: source material partition factors for eight of the nine volatile elements, Sb being the exception. The strong depletion of Te and Se in the mantle, relative to lithophile elements of similar volatility, suggests that 97% of the earth's S, Se and Te may be in the outer core.

  8. Radiation therapy for stage I and II testicular seminoma

    International Nuclear Information System (INIS)

    Latini, P.; Aristei, C.; Maranzano, E.; Checcaglini, F.; Panizza, M.B.; Perrucci, E.; Bellucci, M.C.

    1988-01-01

    From june 1977 through june 1987, 46 patients (36 evaluable) affected by stage I and II non-bulky testicular seminoma were treated with postoperative telecobaltotherapy (TCT). In stage I seminomas, radiotherapy was extended to the omolateral iliac and the para-aortic areas (total dose: 30 Gy over 4 weeks). In stage II seminomas, the subdiaphragmatic lymph nodes were irradiated with 40-45 Gy over 5-6 weeks; after an interval of one month the subdiaphragmatic lymph nodes were irradiated again with a total dose of 25 Gy over 3.5 weeks. Minimal follow-up lasted two years and maximum ten years (average:5.5%) recurrences occurred, but salvage radiotherapy and salvage chemotherapy respectively allowed a complete permanent remission. One patient died from a different neoplasia with no evidence of testicular involvement. The 5-year actuarial survival is 96.6±3.4. In 20% of the patients the side effects were nausea and/or vomiting, easily controlled. No late complications were observed

  9. Second Stage (S-II) Plays Key Role in Apollo missions

    Science.gov (United States)

    1970-01-01

    This photograph of the Saturn V Second Stage (S-II) clearly shows the cluster of five powerful J-2 engines needed to boost the Apollo spacecraft into earth orbit following first stage separation. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  10. The European Dioxin Emission Inventory. Stage II. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Quass, U.; Fermann, M.; Broeker, G.

    2001-07-01

    For Stage II of the European Dioxin Project the following objectives were set: - Amendment of existing emission data collected for most relevant emission sources in order to reduce uncertainties of emission estimates. Collecting first emission data from countries not yet performing dioxin emission measurement programs. Extending the inventory of dioxin emissions to ambient air produced in Stage I by a complementary study on emissions to land and water. Extending the regional scope of data collection to countries in Central Europe. The report of Stage II of the European Dioxin Project is presented in 3 Volumes. Volume 1 contains an overview on the background and approach of different activities carried out and on the results obtained. These results are put into a broader view regarding the dioxin reduction measures in Europe leading to conclusions and recommendation for future work. Volume 2 of the report contains a detailed presentation of the sub-projects carried out. The chapters of Volume 2 are structured in a similar manner and start with a short summary in order to allow for a fast cross-reading. In the case of the desk-top studies an overview of the main results or statements is given. Regarding emission measurements details on the experimental set-up and the facilities being investigated are presented. Volume 3 contains a re-evaluation of the dioxin emission inventory presented for the most relevant sources types in the Stage I report. New data gathered from the projects of Stage II as well as from independent activities in the European countries are considered for a revision of the 1995 emission estimates. Additionally, based on current trends and activities the PCDD/F emissions for the years 2000 and 2005 are estimated. Finally, an attempt is made to evaluate the PCDD/F emission reduction rates which might be possible to achieve by the year 2005 compared to 1985. (orig.)

  11. Radiotherapy for stage I-II non-small cell lung cancer

    International Nuclear Information System (INIS)

    Okamoto, Yoshiaki; Murakami, Masao; Mizowaki, Takashi; Nakajima, Toshifumi; Kuroda, Yasumasa

    1999-01-01

    Surgery has been regarded as the standard treatment for patients with non-small cell lung cancer in the early stage, while radiotherapy has become an effective alternative for medically inoperable patients and those who refuse surgery. We reviewed the records of 31 patients with stage I-II non-small cell lung cancer treated by radiotherapy between 1980 and 1997. There were 15 patients in stage I and 16 in stage II. The variables analyzed for influence on cause-specific survival and loco-regional control were: age, performance status, clinical stage, tumor size, tumor site, radiation field, radiation dose, and combination with chemotherapy. The overall and cause-specific 1-, 2-, 3-, and 5-years survival rates were 71% and 77%; 63% and 73%; 34% and 48%; and 17% and 32%, respectively. Five-year survival rate for patients with peripheral tumor in the lung was 72%, with 70% loco-regional control, while the 5-year survival rate of patients whose tumor originated in the central region was 20%, with 25% loco-regional control. These differences had marginal significance on univariate analysis (P=0.07), but only tumor site (central vs peripheral) showed marginal significant influence on cause-specific survival (P=0.08) and loco-regional control (P=0.07) on multivariate analysis. There were no fatal complications, including radiation-induced myelopathy. The present series showed satisfactory results with definitive radiotherapy for patients with medically inoperable stage I-II non-small cell lung cancer, with results similar to those in recent reports of radiotherapy. The only significant variable was that patients with peripheral tumors had a better prognosis than patients with central tumors. (author)

  12. Experimental investigation of the stability of Fe-rich carbonates in the lower mantle

    Science.gov (United States)

    Boulard, E.; Menguy, N.; Auzende, A.; Benzerara, K.; Bureau, H.; Antonangeli, D.; Corgne, A.; Morard, G.; Siebert, J.; Perrillat, J.; Guyot, F. J.; Fiquet, G.

    2011-12-01

    Carbonates are the main C-bearing minerals that are transported deep in the Earth's mantle via subduction of the oceanic lithosphere [1]. The fate of carbonates at mantle conditions plays a key role in the deep carbon cycle. Decarbonation, melting or reduction of carbonates will affect the extent and the way carbon is recycled into the deep Earth. To clarify the fate of carbonates in the deep mantle, high-pressure high-temperature experiments were carried out up to 105 GPa and 2850 K on oxide assemblages of (Mg,Fe)O + CO2. The presence of Fe(II) in starting materials induces redox reactions from which Fe(II) is oxidized and a part of the carbon is reduced. This leads to an assemblage of magnetite, diamonds, and carbonates or, pressure depending, their newly discovered Fe(III)-bearing high-pressure polymorphs based on a silicate-like chemistry with tetrahedrally coordinated carbon [2]. Our results show the possibility for carbon to be recycled in the lowermost mantle and provide evidence of a possible coexistence of reduced and oxidized carbon at lower mantle conditions. [1] Sleep, N. H., and K. Zahnle (2001) J. Geophys. Res.-Planets 106(E1), 1373-1399. [2] Boulard et al. (2011) PNAS, 108, 5184-5187.

  13. Curcumin and Cholecalciferol in Treating Patients With Previously Untreated Stage 0-II Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma

    Science.gov (United States)

    2018-01-26

    Contiguous Stage II Small Lymphocytic Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Stage 0 Chronic Lymphocytic Leukemia; Stage I Chronic Lymphocytic Leukemia; Stage I Small Lymphocytic Lymphoma; Stage II Chronic Lymphocytic Leukemia

  14. Irradiation in the treatment of Hodgkin disease: a follow-up report

    International Nuclear Information System (INIS)

    Kim, Y.H.; Fayos, J.V.

    1981-01-01

    From 1971 through 1976, 167 patients with Hodgkin disease received radiation therapy. In 132, staging was determined upon laparotomy; the others had clinical staging. Most patients with stage I or II disease received either mantle or para-aortic-iliac irradiation, while the others received more extensive irradiation with or without chemotherapy. Overall five-year actuarial survival rate was 87%; Stage I, 97%; Stage II, 85%; and Stage III, 82%. Fifty-nine of the 167 patients had relapse of disease, and most relapses were seen in Stage II, located in the nodal sites on the opposite side of the diaphragm. Overall five-year relapse-free survival was 58%; Stage I, 94%; Stage II, 43%; and Stage III, 59%. Survival after the first relapse was 69%. Based on their results, the authors feel that Stage I disease of supradiaphragmatic presentation can be treated effectively with mantle field irradiation alone. In treating Stage II disease, mantle field irradiation alone was not optimal, and the authors recommend subtotal nodal irradiation

  15. 78 FR 34303 - Approval and Promulgation of Implementation Plans; North Carolina; Removal of Stage II Gasoline...

    Science.gov (United States)

    2013-06-07

    ... Promulgation of Implementation Plans; North Carolina; Removal of Stage II Gasoline Vapor Recovery Program..., 2009, for the purpose of removing Stage II vapor control requirements for new and upgraded gasoline... Piping for Stage II Vapor Recovery, for all new or improved gasoline tanks. In addition, rule 15A-02D...

  16. Petrological Geodynamics of Mantle Melting II. AlphaMELTS + Multiphase Flow: Dynamic Fractional Melting

    Science.gov (United States)

    Tirone, Massimiliano

    2018-03-01

    In this second installment of a series that aims to investigate the dynamic interaction between the composition and abundance of the solid mantle and its melt products, the classic interpretation of fractional melting is extended to account for the dynamic nature of the process. A multiphase numerical flow model is coupled with the program AlphaMELTS, which provides at the moment possibly the most accurate petrological description of melting based on thermodynamic principles. The conceptual idea of this study is based on a description of the melting process taking place along a 1-D vertical ideal column where chemical equilibrium is assumed to apply in two local sub-systems separately on some spatial and temporal scale. The solid mantle belongs to a local sub-system (ss1) that does not interact chemically with the melt reservoir which forms a second sub-system (ss2). The local melt products are transferred in the melt sub-system ss2 where the melt phase eventually can also crystallize into a different solid assemblage and will evolve dynamically. The main difference with the usual interpretation of fractional melting is that melt is not arbitrarily and instantaneously extracted from the mantle, but instead remains a dynamic component of the model, hence the process is named dynamic fractional melting (DFM). Some of the conditions that may affect the DFM model are investigated in this study, in particular the effect of temperature, mantle velocity at the boundary of the mantle column. A comparison is made with the dynamic equilibrium melting (DEM) model discussed in the first installment. The implications of assuming passive flow or active flow are also considered to some extent. Complete data files of most of the DFM simulations, four animations and two new DEM simulations (passive/active flow) are available following the instructions in the supplementary material.

  17. Cutaneous lesions as presentation form of mantle cell lymphoma

    Directory of Open Access Journals (Sweden)

    Nayra Merino de Paz

    2011-12-01

    Full Text Available Mantle cell lymphoma is a type of no-Hodgkin lymphoma that affects extranodal areas, especially, bone narrow, digestive tract and Waldeyer ring. Here we report a case of mantle cell lymphoma IV Ann Arbor stage with cutaneous lesions on nasal dorsum and gland as the first manifestations. Skin involvement is a very rare manifestation and less than 20 cases have been reported in the literature. The importance of stablishing multidisciplinary relationships for a global approach has been shown by this clinical case.

  18. The role and conditions of second-stage mantle melting in the generation of low-Ti tholeiites and boninites: the case of the Manihiki Plateau and the Troodos ophiolite

    Science.gov (United States)

    Golowin, Roman; Portnyagin, Maxim; Hoernle, Kaj; Sobolev, Alexander; Kuzmin, Dimitry; Werner, Reinhard

    2017-12-01

    High-Mg, low-Ti volcanic rocks from the Manihiki Plateau in the Western Pacific share many geochemical characteristics with subduction-related boninites such as high-Ca boninites from the Troodos ophiolite on Cyprus, which are believed to originate by hydrous re-melting of previously depleted mantle. In this paper we compare the Manihiki rocks and Troodos boninites using a new dataset on the major and trace element composition of whole rocks and glasses from these locations, and new high-precision, electron microprobe analyses of olivine and Cr-spinel in these rocks. Our results show that both low-Ti Manihiki rocks and Troodos boninites could originate by re-melting of a previously depleted lherzolite mantle source (20-25% of total melting with 8-10% melting during the first stage), as indicated by strong depletion of magmas in more to less incompatible elements (Sm/Yb Y 0.5). In comparison with Troodos boninites, the low-Ti Manihiki magmas had distinctively lower H2O contents ( 2 wt% in boninites), 100 °C higher liquidus temperatures at a given olivine Fo-number, lower fO2 (ΔQFM + 0.2) and originated from deeper and hotter mantle (1.4-1.7 GPa, 1440 °C vs. 0.8-1.0 GPa, 1300 °C for Troodos boninites). The data provide new evidence that re-melting of residual upper mantle is not only restricted to subduction zones, where it occurs under hydrous conditions, but can also take place due to interaction of previously depleted upper mantle with mantle plumes from the deep and hotter Earth interior.

  19. Sensitivity analysis of crustal correction for calculation of lithospheric mantle density from gravity data

    DEFF Research Database (Denmark)

    Herceg, Matija; Artemieva, Irina; Thybo, Hans

    2016-01-01

    for the crust and (ii) uncertainties in the seismic crustal structure (thickness and average VP velocities of individual crustal layers, including the sedimentary cover). We examine the propagation of these uncertainties into determinations of lithospheric mantle density and analyse both sources of possible......We investigate how uncertainties in seismic and density structure of the crust propagate to uncertainties in mantle density structure. The analysis is based on interpretation of residual upper-mantle gravity anomalies which are calculated by subtracting (stripping) the gravitational effect...... mantle, knowledge on uncertainties associated with incomplete information on crustal structure is of utmost importance for progress in gravity modelling. Uncertainties in the residual upper-mantle gravity anomalies result chiefly from uncertainties in (i) seismic VP velocity-density conversion...

  20. Early episodes of high-pressure core formation preserved in plume mantle

    Science.gov (United States)

    Jackson, Colin R. M.; Bennett, Neil R.; Du, Zhixue; Cottrell, Elizabeth; Fei, Yingwei

    2018-01-01

    The decay of short-lived iodine (I) and plutonium (Pu) results in xenon (Xe) isotopic anomalies in the mantle that record Earth’s earliest stages of formation. Xe isotopic anomalies have been linked to degassing during accretion, but degassing alone cannot account for the co-occurrence of Xe and tungsten (W) isotopic heterogeneity in plume-derived basalts and their long-term preservation in the mantle. Here we describe measurements of I partitioning between liquid Fe alloys and liquid silicates at high pressure and temperature and propose that Xe isotopic anomalies found in modern plume rocks (that is, rocks with elevated 3He/4He ratios) result from I/Pu fractionations during early, high-pressure episodes of core formation. Our measurements demonstrate that I becomes progressively more siderophile as pressure increases, so that portions of mantle that experienced high-pressure core formation will have large I/Pu depletions not related to volatility. These portions of mantle could be the source of Xe and W anomalies observed in modern plume-derived basalts. Portions of mantle involved in early high-pressure core formation would also be rich in FeO, and hence denser than ambient mantle. This would aid the long-term preservation of these mantle portions, and potentially points to their modern manifestation within seismically slow, deep mantle reservoirs with high 3He/4He ratios.

  1. Segmental mastectomy and radiotherapy as treatment of stage II breast cancer

    International Nuclear Information System (INIS)

    Faria, S.L.; Chiminazzo Junior, H.; Schlupp, W.R.; Cunha, L.S.M. da

    1987-01-01

    The treatment of operable breast cancer with segmental mastectomy and radiotherapy has been described since decade 30. Many recent prospective and retrospective studies have shown the efficacy of this conservative management, particularly in stage I. There are still doubts in its use in stage II. (Author) [pt

  2. Result of Radiation Therapy for Stage I, II Non-Hodgkin Lymphoma

    International Nuclear Information System (INIS)

    Lee, Kyu Chan; Kim, Chul Yong; Choi, Myung Sun

    1993-01-01

    A retrospective analysis was done for 69 patients with Stage I and II non-Hodgkin lymphoma who were treated from May 1981 to December 1990, in the Department of Radiadtion Oncology, Korea University Hospital. We used Ann Arbor Staging system and Working Formulation for histological classification. Forty-three patients(43/69, 62.3%) were Stage I and 26 patients (26/69, 37.7%) were Stage II, and B symptom was found in 10.1%(7/69). Local control rate for all patients was 88.4%(61/69), with 80% (12/15) for nodal lymphoma and 90.7%(49/54) for extra nodal lymphoma. The total failure rate was 34.8%(24/69). Five of 24 (20.8%) patients who were failed developed local failure only, 12.5%(3/24) local failure with distant failure, and distant failure only were found in 66.7%(16/24). Between nodal lymphoma and extra nodal lymphoma, there was no significant survival difference, but extra nodal lymphoma showed higher incidence

  3. Evaluation of the I. Stage of decommissioning and implementation of the II. Stage of decommissioning of NPP V1

    International Nuclear Information System (INIS)

    Hrasnova, E.

    2015-01-01

    In this paper author deals with following aspects: 1. Introduction of company Nuclear and Decommissioning Company, plc; 2. Evaluation of the I. stage of decommissioning and implementation of the II. Stage of decommissioning of NPP V1; (author)

  4. Stage I/II endometrial carcinomas: preoperative radiotherapy: results

    International Nuclear Information System (INIS)

    Maingon, P.; Belichard, C.; Horiot, J.C.; Barillot, I.; Fraisse, J.; Collin, F.

    1996-01-01

    The AIM of this retrospective study is to analyse the indications and the results of treatment of endometrial carcinomas by preoperative radiotherapy. MATERIAL: From 1976 to 1995, 183 patients FIGO stage I or II were treated by preoperative radiotherapy consisting in 95 cases of external radiotherapy (XRT) and brachytherapy (BT) followed by surgery (S) and, in 88 cases of BT alone before surgery, XRT was indicated in cases of grade 2 or 3 and/or cervical involvement. METHODS: XRT was delivered with a 4-fields technique to 40 Gy in 20 fractions with a medial shielding at 30 Gy. BT was done with low dose rate Cs137 and Fletcher-Suit-Delclos applicators with two intra-uterine tubes and vaginal ovoieds. Complications were scored using the French-Italian syllabus. RESULTS: Five-year actuarial survival rates per stage are: Ia=91%, Ib=83%, II=71%, and per grade: G1=80%, G2=79%, G3=90%. Failures were pelvic in 5/183 (2.7%), vaginal in 4 cases (2%) and nodal in 2 cases (1%). Twelve patients developed metastases (6.5%). Complications were analysed during the radiotherapy, after the surgery and with unlimited follow-up. After BT/S, 12 grade 1, 1 grade 2 and 1 grade 3 complications were observed. In the group of patients treated by RT/BT/S, 22 grade 1, 11 grade 2, 4 grade 3 occurred. There is no statistical correlation between complications and parameters of treatment (XRT, hwt, HWT, reference dose to the bladder and rectum, dose rate of brachytherapy). SUMMARY: Preoperative irradiation is an effective and safe treatment of high risk stage I/II endometrial carcinomas. Results seem independent of the pathology grade

  5. Short Course Vaginal Cuff Brachytherapy in Treating Patients With Stage I-II Endometrial Cancer

    Science.gov (United States)

    2018-04-17

    Endometrial Clear Cell Adenocarcinoma; Endometrial Endometrioid Adenocarcinoma; Endometrial Serous Adenocarcinoma; Stage I Uterine Corpus Cancer; Stage IA Uterine Corpus Cancer; Stage IB Uterine Corpus Cancer; Stage II Uterine Corpus Cancer; Uterine Corpus Carcinosarcoma; Uterine Corpus Sarcoma

  6. Rare gas systematics: Formation of the atmosphere, evolution and structure of the Earth's mantle

    International Nuclear Information System (INIS)

    Allegre, C.J.; Staudacher, T.; Sarda, P.; Paris-6 Univ., 75; Paris-7 Univ., 75

    1987-01-01

    To explain the rare gas content and isotopic composition measured in modern terrestrial materials we explore in this paper an Earth model based on four reservoirs: atmosphere, continental crust, upper mantle and lower mantle. This exploration employs three tools: mass balance equations, the concept of mean age of outgassing and the systematic use of all of the rare gases involving both absolute amount and isotopic composition. The results obtained are as follows: half of the Earth's mantle is 99% outgassed. Outgassing occurred in an early very intense stage within the first 50 Ma of Earth history and a slow continuous stage which continues to the present day. The mean age of the atmosphere is 4.4 Ga. Our model with four main reservoirs explains quantitatively both isotopic and chemical ratios, assuming that He migrates from the lower to the upper mantle whereas the heavy rare gases did not. Noble gas fluxes for He, Ar and Xe from different reservoirs have been estimated. The results constrain the K content in the earth to 278 ppm. Several geodynamic consequences are discussed. (orig.)

  7. Execution of mantle field with multileaf collimator: A simple approach

    Directory of Open Access Journals (Sweden)

    Prabhakar Ramachandran

    2008-01-01

    Full Text Available Background: Until very recently mantle field radiotherapy remained the gold standard for the treatment of favorable early-stage Hodgkin′s lymphoma. The classic mantle includes all the major lymph nodes above the diaphragm and extends from the inferior portion of the mandible to the level of the insertion of the diaphragm. Aims: To describe a simple technique that has been devised to treat the mantle field with the help of multileaf collimator and using computed tomography (CT-based treatment planning. Materials and Methods: CT scan was performed with the patient in the supine position and the datasets were transferred to the Eclipse™ treatment planning system. Elekta Precise™ linear accelerator equipped with 40 pairs of multileaf collimator (MLC was used for the execution of the mantle field. The MLC′s shapes were designed to take the shape of the conventional customized blocks used for treatment of mantle field. The anterior mantle field was divided into three separate MLC segments with the collimator kept at 0°. The first MLC segment was shaped to cover the neck, clavicular regions, and mediastinum. The second and the third MLC segments covered the right and left axilla, respectively. The posterior fields were opposed to the anterior subfields in a similar fashion. The dose was prescribed at the midplane, using reference points. Results and Conclusion: The technique described in this study is very simple, easy to implement, and avoids unnecessary delay in the execution of the mantle field. The mantle field can be easily shaped with the multileaf collimators, without any collimator rotation.

  8. Compositional Variation of Terrestrial Mantle Apatites and Implications for the Halogen and Water Budgets of the Terrestrial Mantle

    Science.gov (United States)

    Roden, M.; Patino Douce, A. E.; Chaumba, J. B.; Fleisher, C.; Yogodzinski, G. M.

    2011-12-01

    Apatite in ultramafic xenoliths from various tectonic enviroments including arc (Kamchatka), plume (Hawaii), and intraplate (Lunar Crater, Nunivak, Colorado Plateau) were analyzed by electron microprobe with the aim of characterizing the Cl and F contents, and from these measured compositions to infer the nature of fluids/melts that the apatites equilibrated with. The impetus for the study derived from the generalization of O'Reilly and Griffin (1) that mantle-derived metasomatic apatites tend to be Cl-rich and mantle-derived igneous apatites tend to be F-rich. Our work largely corroborates their generalization with Cl- and/or H2O-rich compositions characterizing the apatites from Nunivak and Kamchatka while apatites from igneous or Group II xenoliths tend to be Cl-poor and be either nearly pure fluorapatite or a mix of hydroxylapatite and fluorapatite. We attribute the Cl-rich nature of the Kamchatka apatites to formation from Cl-rich fluids generated from subducted lithosphere; however the Nunivak occurrence is far removed from subducted lithosphere and may reflect a deep seated source for Cl as also indicated by brine inclusions in diamonds, Cl-rich apatites in carbonate-bearing xenoliths and a Cl-rich signature in some plumes such as Iceland, Azores and Samoa. One curious aspect of mantle-derived apatite compositions is that xenoliths with evidence of carbonatitic metasomatism commonly have Cl-rich apatites while apatites from carbonatites are invariably Cl-poor - perhaps reflecting loss of Cl in fluids evolved from the carbonatitic magma. Apatites from Group II xenoliths at Hawaii are solid solutions between fluorapatite and hydroxylapatite and show no evidence for deep-seated Cl at Hawaii. Samples of the terrestrial mantle are almost uniformly characterized by mineral assemblages with a single Ca-rich phosphate phase but the mantles of Mars, Vesta and the Moon have two Ca-rich phosphates, apatite and volatile-poor merrillite - apatite compositions existing

  9. Risk of recurrence in patients with colon cancer stage II and III

    DEFF Research Database (Denmark)

    Bockelman, C.; Engelmann, Bodil E.; Kaprio, T.

    2015-01-01

    Background. Adjuvant chemotherapy is established routine therapy for colon cancer (CC) patients with radically resected stage III and 'high-risk' stage II disease. The decision on recommending adjuvant chemotherapy, however, is based on data from older patient cohorts not reflecting improvements...

  10. Lithology and temperature: How key mantle variables control rift volcanism

    Science.gov (United States)

    Shorttle, O.; Hoggard, M.; Matthews, S.; Maclennan, J.

    2015-12-01

    Continental rifting is often associated with extensive magmatic activity, emplacing millions of cubic kilometres of basalt and triggering environmental change. The lasting geological record of this volcanic catastrophism are the large igneous provinces found at the margins of many continents and abrupt extinctions in the fossil record, most strikingly that found at the Permo-Triassic boundary. Rather than being considered purely a passive plate tectonic phenomenon, these episodes are frequently explained by the involvement of mantle plumes, upwellings of mantle rock made buoyant by their high temperatures. However, there has been debate over the relative role of the mantle's temperature and composition in generating the large volumes of magma involved in rift and intra-plate volcanism, and even when the mantle is inferred to be hot, this has been variously attributed to mantle plumes or continental insulation effects. To help resolve these uncertainties we have combined geochemical, geophysical and modelling results in a two stage approach: Firstly, we have investigated how mantle composition and temperature contribute to melting beneath Iceland, the present day manifestation of the mantle plume implicated in the 54Ma break up of the North Atlantic. By considering both the igneous crustal production on Iceland and the chemistry of its basalts we have been able to place stringent constraints on the viable temperature and lithology of the Icelandic mantle. Although a >100°C excess temperature is required to generate Iceland's thick igneous crust, geochemistry also indicates that pyroxenite comprises 10% of its source. Therefore, the dynamics of rifting on Iceland are modulated both by thermal and compositional mantle anomalies. Secondly, we have performed a global assessment of the mantle's post break-up thermal history to determine the amplitude and longevity of continental insulation in driving excess volcanism. Using seismically constrained igneous crustal

  11. [Value of transcutaneous staged dynamic oximetry of stage II arteritis of the leg].

    Science.gov (United States)

    Grard, C; Desmytterre, J; Vinckier, L; Hatron, P Y; Roux, J P; Warembourg, H; Devulder, B

    1990-03-01

    The clinical and prognostic value of transcutaneous oxygen pressure measurements at rest has been established in Leriche Stage III and IV occlusive peripheral arterial disease but is controversial in Stage II because there is an overlap of transcutaneous pO2 (Tc pO2) values with those of normal subjects. The authors report the results of Tc pO2 measurements during exercise testing in a group of patients with Stage II occlusive arterial disease of the lower limbs. Seventy-eight patients with an average age of 53 years (range 40 to 65 years) whose claudication perimeter and site of pain had been carefully assessed and who had also recently undergone Doppler arterial examination and arteriography and 35 control subjects with an average age of 54 years (range 45 to 70 years) were studied. The Tc pO2 was continuously measured with a multimodular Kontron Supermon at 4 different sites simultaneously: precordium (reference probe), thigh, calf and foot in the dorsal recumbent position after 30 minutes rest, during a standardised exercise stress test at 50 watts and during the recovery phase. The results were expressed as ratio of tissue oxygenation (RTO): thigh, calf or foot Tc pO2/precordial Tc pO2 X 100 in order to take into account the patients cardiorespiratory status and adaptation to exercise. The RTO in normal subjects remained at the upper limits of the resting value throughout exercise and then returned slowly to basal values during the recovery phase.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Prognostic importance of VEGF-A haplotype combinations in a stage II colon cancer population

    DEFF Research Database (Denmark)

    Kjaer-Frifeldt, Sanne; Fredslund, Rikke; Lindebjerg, Jan

    2012-01-01

    To investigate the prognostic effect of three VEGF-A SNPs, -2578, -460 and 405, as well as the corresponding haplotype combinations, in a unique population of stage II colon cancer patients.......To investigate the prognostic effect of three VEGF-A SNPs, -2578, -460 and 405, as well as the corresponding haplotype combinations, in a unique population of stage II colon cancer patients....

  13. Linking the tectonic evolution with fluid history in magma-poor rifted margins: tracking mantle- and continental crust-related fluids

    Science.gov (United States)

    Pinto, V. H. G.; Manatschal, G.; Karpoff, A. M.

    2014-12-01

    The thinning of the crust and the exhumation of subcontinental mantle is accompanied by a series of extensional detachment faults. Exhumation of mantle and crustal rocks is intimately related to percolation of fluids along detachment faults leading to changes in mineralogy and chemistry of the mantle, crustal and sedimentary rocks. Field observation, analytical methods, refraction/reflection and well-core data, allowed us to investigate the role of fluids in the Iberian margin and former Alpine Tethys distal margins and the Pyrenees rifted system. In the continental crust, fluid-rock interaction leads to saussuritization that produces Si and Ca enriched fluids found in forms of veins along the fault zone. In the zone of exhumed mantle, large amounts of water are absorbed in the first 5-6 km of serpentinized mantle, which has the counter-effect of depleting the mantle of elements (e.g., Si, Ca, Mg, Fe, Mn, Ni and Cr) forming mantle-related fluids. Using Cr-Ni-V and Fe-Mn as tracers, we show that in the distal margin, mantle-related fluids used detachment faults as pathways and interacted with the overlying crust, the sedimentary basin and the seawater, while further inward parts of the margin, continental crust-related fluids enriched in Si and Ca impregnated the fault zone and may have affected the sedimentary basin. The overall observations and results enable us to show when, where and how these interactions occurred during the formation of the rifted margin. In a first stage, continental crust-related fluids dominated the rifted systems. During the second stage, mantle-related fluids affected the overlying syn-tectonic sediments through direct migration along detachment faults at the future distal margin. In a third stage, these fluids reached the seafloor, "polluted" the seawater and were absorbed by post-tectonic sediments. We conclude that a significant amount of serpentinization occurred underneath the thinned continental crust, that the mantle-related fluids

  14. Breast carcinoma conservative treatment. Stages I and II

    International Nuclear Information System (INIS)

    Monti, C.R.

    1990-01-01

    From 1981 to 1988, 265 patients with breast cancer stages I and II (UICC-1987), were evaluated after conservative treatment with quadrantectomy plus axillectomy, radiotherapy and chemotherapy. After surgical treatment, the patients were submitted to radiation therapy in the breast. One hundred and fifty six (58,8%) patients were submitted to adjuvant chemotherapy. The median clinical follow-up period was 42.8 months with a minimum of 24 and a maximum of 99 months. Six (2,3%) patients presented local recurrence and 48 (18,1%) presented distant metastasis. After five years the total survival rate was 89,7% and the disease free survival rate was 75% in the same period. The study did not show significant differences among the clinical stages classified after surgery and the use of adjuvant chemotherapy did not influence the results of the many stages. (author). 194 refs, 33 figs, 6 tabs

  15. Development of Capabilities for New Experimental Studies on the Elasticity and Rheology of Lower Mantle Minerals

    Science.gov (United States)

    Triplett, R.; Weidner, D.; Whitaker, M. L.; Chen, H.; Li, L.

    2017-12-01

    Key mineralogical components of the mid-mantle of the Earth have historically been difficult to obtain elasticity data on because they either cannot be recovered to ambient conditions (e.g. calcium silicate perovskite) or back-transform during experimental preparation (e.g. magnesium silicate perovskite). Recently the conditions of the mid-mantle (14+ GPa, 1500+ K) and even of the lower mantle (24+ GPa, 1800+ K) have become reachable using multi-anvil apparatuses (MAA) with in-situ synchrotron x-ray capabilities, but the capabilities of these facilities have not yet fully matured. Examples include that reaching such pressures typically results in samples that are too small for ultrasonics, the few ultrasonics experiments done at these conditions have extremely limited x-ray visibility, and rheological experiments that apply differential stress have not been done at these conditions on large volume samples. The pressure reachable in a Large Volume Press (LVP) is limited by the properties of available ultra-hard (UH) materials such as tungsten carbide (WC) and x-ray transparent polycrystalline diamond (PCD) and cubic boron nitride (cBN). A key factor is the interaction of 1st stage anvils and anvils of UH materials; obtaining WC anvils of larger size is prohibitive in both capability and cost, and anvils of hardened steel are limited in the tonnage that can be applied before damage occurs. Other complications include the difference in compressibility between WC and PCD/cBN anvils and the availability of WC with simultaneous high compressive strength (pressure gain per tonnage) and high transverse rupture strength (lower chance of blowout and reusability). The DT25 press to be used at the new NSLS-II beamline XPD-D is a Kawaii-style LVP MAA which accepts 25 mm UH 2nd-stage anvils and has the capability to apply a differential load while at extreme conditions. We report on our development of techniques to do new and expanded experiments at lower mantle conditions

  16. Upper mantle flow in the western Mediterranean

    Energy Technology Data Exchange (ETDEWEB)

    Panza, G F [Dipartimento di Scienze della Terra, Universita degli Studi di Trieste, Trieste (Italy) and Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Raykova, R [Geophysical Institute of BAS, Sofia (Bulgaria) and Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna (Italy); Carminati, E; Doglioni, C [Dipartimento di Scienze della Terra, Universita degli Studi di Trieste, Trieste (Italy)

    2006-07-15

    Two cross-sections of the western Mediterranean Neogene-to-present backarc basin are presented, in which geological and geophysical data of the Transmed project are tied to a new shear-wave tomography. Major results are i) the presence of a well stratified upper mantle beneath the older African continent, with a marked low-velocity layer between 130-200 km of depth; ii) the dilution of this layer within the younger western Mediterranean backarc basin to the north, and iii) the easterly raising of a shallower low-velocity layer from about 140 km to about 30 km in the Tyrrhenian active part of the backarc basin. These findings suggest upper mantle circulation in the western Mediterranean backarc basin, mostly easterly-directed and affecting the boundary between upper asthenosphere (LVZ) and lower asthenosphere, which undulates between about 180 km and 280 km. (author)

  17. Upper mantle flow in the western Mediterranean

    International Nuclear Information System (INIS)

    Panza, G.F.; Raykova, R.; Carminati, E.; Doglioni, C.

    2006-07-01

    Two cross-sections of the western Mediterranean Neogene-to-present backarc basin are presented, in which geological and geophysical data of the Transmed project are tied to a new shear-wave tomography. Major results are i) the presence of a well stratified upper mantle beneath the older African continent, with a marked low-velocity layer between 130-200 km of depth; ii) the dilution of this layer within the younger western Mediterranean backarc basin to the north, and iii) the easterly raising of a shallower low-velocity layer from about 140 km to about 30 km in the Tyrrhenian active part of the backarc basin. These findings suggest upper mantle circulation in the western Mediterranean backarc basin, mostly easterly-directed and affecting the boundary between upper asthenosphere (LVZ) and lower asthenosphere, which undulates between about 180 km and 280 km. (author)

  18. Breast-Conserving Surgery Followed by Radiation Therapy With MRI-Detected Stage I or Stage II Breast Cancer

    Science.gov (United States)

    2011-12-07

    Ductal Breast Carcinoma in Situ; Estrogen Receptor-negative Breast Cancer; Estrogen Receptor-positive Breast Cancer; HER2-negative Breast Cancer; HER2-positive Breast Cancer; Invasive Ductal Breast Carcinoma; Invasive Lobular Breast Carcinoma; Male Breast Cancer; Medullary Ductal Breast Carcinoma With Lymphocytic Infiltrate; Mucinous Ductal Breast Carcinoma; Papillary Ductal Breast Carcinoma; Progesterone Receptor-negative Breast Cancer; Progesterone Receptor-positive Breast Cancer; Stage I Breast Cancer; Stage II Breast Cancer; Tubular Ductal Breast Carcinoma

  19. PTT functional recovery in early stage II PTTD after tendon balancing and calcaneal lengthening osteotomy.

    Science.gov (United States)

    Brilhault, Jean; Noël, Vincent

    2012-10-01

    The decision to offer surgery for Stage II posterior tibial tendon deficiency (PTTD) is a difficult one since orthotic treatment has been documented to be a viable alternative to surgery at this stage. Taking this into consideration we limited our treatment to bony realignment by a lengthening calcaneus Evans osteotomy and tendon balancing. The goal of the study was to clinically evaluate PTT functional recovery with this procedure. The patient population included 17 feet in 13 patients. Inclusion was limited to early Stage II PTTD flatfeet with grossly intact but deficient PTT. Deficiency was assessed by the lack of hindfoot inversion during single heel rise test. The surgical procedure included an Evans calcaneal opening wedge osteotomy with triceps surae and peroneus brevis tendon lengthening. PTT function at follow up was evaluated by an independent examiner. Evaluation was performed at an average of 4 (range, 2 to 6.3) years. One case presented postoperative subtalar pain that required subtalar fusion. Every foot could perform a single heel rise with 13 feet having active inversion of the hindfoot during elevation. The results of this study provide evidence of PTT functional recovery without augmentation in early Stage II. It challenges our understanding of early Stage II PTTD as well as the surgical guidelines recommending PTT augmentation at this specific stage.

  20. Postoperative radiotherapy for stage II and III rectal cancer

    International Nuclear Information System (INIS)

    Qian Liting; Song Yongwen; Liu Xinfan; Yu Zihao; Qian Tunan; Li Yexiong

    2003-01-01

    Objective: To evaluate the impact of postoperative adjuvant radiotherapy, compared with surgery alone for rectal cancer. Methods: From January 1994 to October 1997, 192 patients with stage II or III rectal cancer were treated by radical resection and postoperative radiotherapy (Group S + R) and 51 patients with the same stage lesions underwent surgery alone (Group S). The median dose of radiation was 50(32-62) Gy. Kaplan-Meier method and Log-rank test were used for analysis. Results: The 5-year overall and disease-free survival rates were 60.3% and 58.3%, respectively. The overall 5-year survival rate was 59.4% in Group S + R and 64.7% in Group S, and the 5-year disease-free survival rates were 57.0% and 66.4%, respectively. There were no significant differences between either group (P=0.601 and P=0.424). The disease-free survival was not significantly prolonged in Group S + R as compared with that of Group S. The local recurrence rate was evidently reduced in Group S + R (15.8% v 26.8%, P=0.043). Conclusion: Local recurrence is a major cause of morbidity and mortality in rectal cancer. Postoperative radiotherapy, though reduces the incidence of local recurrence, does not improve the survival in the treatment of stage II and III diseases

  1. Immunohistochemical detection of cdc2 is useful in predicting survival in patients with mantle cell lymphoma.

    Science.gov (United States)

    Hui, David; Reiman, Tony; Hanson, John; Linford, Rick; Wong, Winson; Belch, Andrew; Lai, Raymond

    2005-09-01

    Recent cDNA microarray studies have reported the prognostic value of several genes in mantle cell lymphoma patients. We aimed to validate the prognostic significance of three of these genes: alpha-tubulin, cdc2, and CENP-F. The protein expression of alpha-tubulin, cdc2, and CENP-F was assessed using immunohistochemistry. Their immunoreactivity in 48 formalin-fixed/paraffin-embedded mantle cell lymphoma tumors was determined by estimating the percentage of positive cells. These results were correlated with the expression of proliferation marker Ki67 and survival. Of these 48 mantle cell lymphoma patients, 41 were men and seven were women. The median age at time of diagnosis was 64.5 years, and the overall median survival was 40 months. In benign lymph nodes, the expression of cdc2 and alpha-tubulin was restricted to the germinal centers; mantle zones were negative. Expression of CENP-F was more uniformly distributed. In mantle cell lymphoma, Ki67 significantly correlated with all three markers (P50%) and cdc2 (>25%) significantly correlated with shorter survival (Por=2 correlated with worse clinical outcome, and high clinical stage (ie 4 vs stage. We have validated the prognostic value of cdc2, and confirmed that of Ki67, in a cohort of mantle cell lymphoma patients. Immunohistochemical detection of cdc2 and Ki67 may be a useful and simple method in evaluating the prognosis of mantle cell lymphoma patients.

  2. Brentuximab Vedotin + Rituximab as Frontline Therapy for Pts w/ CD30+ and/or EBV+ Lymphomas

    Science.gov (United States)

    2015-04-28

    Adult Grade III Lymphomatoid Granulomatosis; Adult Nasal Type Extranodal NK/T-cell Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Contiguous Stage II Adult Burkitt Lymphoma; Contiguous Stage II Adult Diffuse Large Cell Lymphoma; Contiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Contiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Contiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Contiguous Stage II Adult Lymphoblastic Lymphoma; Contiguous Stage II Grade 1 Follicular Lymphoma; Contiguous Stage II Grade 2 Follicular Lymphoma; Contiguous Stage II Grade 3 Follicular Lymphoma; Contiguous Stage II Mantle Cell Lymphoma; Contiguous Stage II Marginal Zone Lymphoma; Contiguous Stage II Small Lymphocytic Lymphoma; Cutaneous B-cell Non-Hodgkin Lymphoma; Epstein-Barr Virus Infection; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Hepatosplenic T-cell Lymphoma; Intraocular Lymphoma; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Adult Burkitt Lymphoma; Noncontiguous Stage II Adult Diffuse Large Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Noncontiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Noncontiguous Stage II Adult Lymphoblastic Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Mantle Cell Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Noncutaneous Extranodal Lymphoma; Peripheral T-cell Lymphoma; Post-transplant Lymphoproliferative Disorder; Progressive Hairy Cell Leukemia, Initial Treatment; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Grade III Lymphomatoid Granulomatosis

  3. Resistance Torque Based Variable Duty-Cycle Control Method for a Stage II Compressor

    Science.gov (United States)

    Zhong, Meipeng; Zheng, Shuiying

    2017-07-01

    The resistance torque of a piston stage II compressor generates strenuous fluctuations in a rotational period, and this can lead to negative influences on the working performance of the compressor. To restrain the strenuous fluctuations in the piston stage II compressor, a variable duty-cycle control method based on the resistance torque is proposed. A dynamic model of a stage II compressor is set up, and the resistance torque and other characteristic parameters are acquired as the control targets. Then, a variable duty-cycle control method is applied to track the resistance torque, thereby improving the working performance of the compressor. Simulated results show that the compressor, driven by the proposed method, requires lower current, while the rotating speed and the output torque remain comparable to the traditional variable-frequency control methods. A variable duty-cycle control system is developed, and the experimental results prove that the proposed method can help reduce the specific power, input power, and working noise of the compressor to 0.97 kW·m-3·min-1, 0.09 kW and 3.10 dB, respectively, under the same conditions of discharge pressure of 2.00 MPa and a discharge volume of 0.095 m3/min. The proposed variable duty-cycle control method tracks the resistance torque dynamically, and improves the working performance of a Stage II Compressor. The proposed variable duty-cycle control method can be applied to other compressors, and can provide theoretical guidance for the compressor.

  4. 78 FR 58184 - Approval and Promulgation of Implementation Plans; North Carolina; Removal of Stage II Gasoline...

    Science.gov (United States)

    2013-09-23

    ...] Approval and Promulgation of Implementation Plans; North Carolina; Removal of Stage II Gasoline Vapor... measures for new and upgraded gasoline dispensing facilities in the State. The September 18, 2009, SIP... .0953), entitled Vapor Return Piping for Stage II Vapor Recovery, for all new or improved gasoline tanks...

  5. Prognostic value of stem cell quantification in stage II colon cancer.

    Directory of Open Access Journals (Sweden)

    Maria Angeles Vaz

    Full Text Available BACKGROUND: Cancer stem cells (CSCs are a subset of tumor cells with capacity to self-renew and generate the diverse cells that make up the tumor. The aim of this study is to evaluate the prognostic value of CSCs in a highly homogeneous population of stage II colon cancer. METHODS: One hundred stage II colon cancer patients treated by the same surgical team between 1977 and 2005 were retrospectively analyzed. None of the patients received adjuvant chemotherapy. Inmunohistochemistry expression of CD133, NANOG and CK20 was scored, using four levels: 50% positivity. Kaplan-Meier analysis and log rank test were used to compare survival. RESULTS: The average patient age was 68 years (patients were between 45-92 years of age and median follow up was 5.8 years. There was recurrent disease in 17 (17%; CD133 expression (defined by >10% positivity was shown in 60% of the tumors, in 95% for NANOG and 78% for CK20. No correlation was found among expression levels of CD133, NANOG or CK20 and relapse-free survival (RFS or overall survival (OS. However, a statistical significant correlation was found between established pathological prognostic factors and RFS and OS. CONCLUSIONS: Stem Cell quantification defined by CD133 and NANOG expression has no correlation with RFS or OS in this cohort of Stage II colon cancer.

  6. Compositionally heterogeneous podiform chromitite in the Shetland Ophiolite Complex (Scotland): Implications for chromitite petrogenesis and late-stage alteration in the upper mantle portion of a supra-subduction zone ophiolite

    Science.gov (United States)

    Derbyshire, E. J.; O'Driscoll, B.; Lenaz, D.; Gertisser, R.; Kronz, A.

    2013-03-01

    The mantle sequence of the ~ 492 Ma Shetland Ophiolite Complex (SOC; Scotland) contains abundant compositionally heterogeneous podiform chromitite bodies enclosed in elongate dunite lenses in the vicinity of the petrological Moho. Chromitite petrogenesis and late-stage alteration events recorded in these seams are examined here using petrography, mineral chemistry and crystal structural data. The resistant nature of Cr-spinel to serpentinisation and other late-stage alteration means that primary igneous compositions are preserved in unaltered crystal cores. Chromitite mineralogy and texture from five sampled localities at The Viels, Hagdale, Harold's Grave, Nikka Vord and Cliff reveal significant inter-pod chemical heterogeneity. The Cr-spinel mineral chemistry is consistent with supra-subduction zone melt extraction from the SOC peridotites. The occurrence of chromitite seams in the centres of the dunite lenses combined with variable Cr-spinel compositions at different chromitite seam localities supports a model of chromitite formation from spatially (and temporally?) fluctuating amounts of melt-rock interaction through channelised and/or porous melt flow. Pervasive serpentinisation of the SOC has led to the almost complete replacement of the primary (mantle) silicate mineral assemblages with serpentine (lizardite with minor chrysotile and antigorite). Magmatic sulphide (e.g., pentlandite) in dunite and chromitite is locally converted to reduced Ni-sulphide varieties (e.g., heazlewoodite and millerite). A post-serpentinisation (prograde) oxidisation event is recorded in the extensively altered Cliff chromitite seams in the west of the studied area, where chromitite Cr-spinel is extensively altered to ferritchromit. The ferritchromit may comprise > 50% of the volume of the Cliff Cr-spinels and contain appreciable quantities of 1-2 μm inclusions of sperrylite (PtAs2) and Ni-arsenide, signifying the coeval formation of these minerals with ferritchromit at

  7. Crust-mantle branch of the global carbon cycle and origin of deep-seated hydrocarbons

    Directory of Open Access Journals (Sweden)

    Sorokhtin N. O.

    2018-03-01

    Full Text Available The processes of multi-stage and polycyclic transformation and transfer of carbon in the crust and mantle have been described. The sediments drawn in the plate underthrust zones break down, become transformed and altered by metamorphic events, and part of the newly formed carbon compounds is transferred by the mantle convective currents to rift zones of the mid-oceanic ridges and carried up to the surface as hydrocarbons of various composition and carbon dioxide. This material becomes re-deposited on the sea floor as sediments forming carbonaceous and carbon-bearing units. As a result of multi-stage mechanism of physical and chemical transformations in the crust-mantle areas of the Earth hydrocarbon compounds acquire features of abiogenic origin remaining, in fact, exogenic. The revealed crust-mantle carbon cycle represents part of a global process for the cyclic carbon transfer from the atmosphere to the mantle and back. The scale of its manifestation is likely not so wide, and numerous small (mm and portions of millimeters particles of exogenic substance and dispersed carbon drawn in the plate underthrust zones form a stable geochemical tail of the crustal direction in the mantle propagating in the plane of convective currents motion. The scale of this process may be indirectly suggested by the volumes of hydrocarbon and carbon dioxide de-gassing and hydrogen in the rift systems of the Earth crust. The amount of generated hydrocarbon gases with deep-seated origin cannot form large gas and oil-and-gas fields since their significant part is transferred to the atmosphere. Just some portion of compounds may be deposited in oceanic sediments and generate gas-hydrate pools.

  8. Polyphase serpentinization history of Mariana forearc mantle: observations on the microfabric of ultramafic clasts from ODP Leg 195, Site 1200

    Science.gov (United States)

    Kahl, Wolf-Achim; Jöns, Niels; Bach, Wolfgang; Klein, Frieder

    2013-04-01

    In the forearc of the Mariana subduction zone system, a number of seamounts form from extrusion of blueschist and serpentine mud. Ocean Drilling Program Leg 195 drilled the South Chamorro seamount, where ultramafic clasts occur within the mud matrix. These clasts show a complex serpentinization history, which bears the potential for tracking the alteration history during uplift and cooling of mantle wedge rocks to the seafloor. Moreover, the microfabrics of the highly serpentinized harzburgite and dunite clasts exhibit evidence for multiple fracturing events in the forearc mantle. These, in turn, lead to fluid influx and varied styles of serpentinization of harzburgite and dunite. The serpentinized ultramafic clasts exhibit a variety of microfabrics that range from virtually undeformed to strongly deformed samples. Pervasively serpentinized harzburgites feature either an equigranular fabric of serpentinized olivine and orthopyroxene crystals, or different vein generations related to multiple stages of serpentinization. Several types of fluid pathways in harzburgites are present: (i) veins containing brucite and iron oxides, developed linearly without marked conformance with the rock fabric. In places, these veins developed mm-cm wide halos with finger-shaped serpentinization fronts. Veins of type (i) are either developed as syntaxial veins from a single crack-seal event with large magnetite crystals growing from one wall to the other (as confirmed with high-resolution X-ray microtomography), or formed by multiple fluid events. (ii) serpentine veins that encompass regions of marginally serpentinized, microgranular olivine and large orthopyroxene crystals. (iii) extensional serpentine veins (known as "Frankenstein" type). In the clasts studied, their occurrence is restricted to the halo region of type (i) veins. (iv) as a late-stage feature, extensional veins documenting multiple crack-seal events can be present in the serpentinites (either in undeformed regions with

  9. Multi-stage mixing in subduction zone: Application to Merapi volcano, Indonesia

    Science.gov (United States)

    Debaille, V.; Doucelance, R.; Weis, D.; Schiano, P.

    2003-04-01

    Basalts sampling subduction zone volcanism (IAB) often show binary mixing relationship in classical Sr-Nd, Pb-Pb, Sr-Pb isotopic diagrams, generally interpreted as reflecting the involvement of two components in their source. However, several authors have highlighted the presence of minimum three components in such a geodynamical context: mantle wedge, subducted and altered oceanic crust and subducted sediments. The overlying continental crust can also contribute by contamination and assimilation in magma chambers and/or during magma ascent. Here we present a multi-stage model to obtain a two end-member mixing from three components (mantle wedge, altered oceanic crust and sediments). The first stage of the model considers the metasomatism of the mantle wedge by fluids and/or melts released by subducted materials (altered oceanic crust and associated sediments), considering mobility and partition coefficient of trace elements in hydrated fluids and silicate melts. This results in the generation of two distinct end-members, reducing the number of components (mantle wedge, oceanic crust, sediments) from three to two. The second stage of the model concerns the binary mixing of the two end-members thus defined: mantle wedge metasomatized by slab-derived fluids and mantle wedge metasomatized by sediment-derived fluids. This model has been applied on a new isotopic data set (Sr, Nd and Pb, analyzed by TIMS and MC-ICP-MS) of Merapi volcano (Java island, Indonesia). Previous studies have suggested three distinct components in the source of indonesian lavas: mantle wedge, subducted sediments and altered oceanic crust. Moreover, it has been shown that crustal contamination does not significantly affect isotopic ratios of lavas. The multi-stage model proposed here is able to reproduce the binary mixing observed in lavas of Merapi, and a set of numerical values of bulk partition coefficient is given that accounts for the genesis of lavas.

  10. Density Anomalies in the Mantle and the Gravitational Core-Mantle Interaction

    Science.gov (United States)

    Kuang, Weijia; Liu, Lanbo

    2003-01-01

    Seismic studies suggest that the bulk of the mantle is heterogeneous, with density variations in depth as well as in horizontal directions (latitude and longitude). This density variation produces a three- dimensional gravity field throughout the Earth. On the other hand, the core density also varies in both time and space, due to convective core flow. Consequently, the fluid outer core and the solid mantle interact gravitationally due to the mass anomalies in both regions. This gravitational core-mantle interaction could play a significant role in exchange of angular momentum between the core and the mantle, and thus the change in Earth's rotation on time scales of decades and longer. Aiming at estimating the significance of the gravitational core-mantle interaction on Earth's rotation variation, we introduce in our MoSST core dynamics model a heterogeneous mantle, with a density distribution derived from seismic results. In this model, the core convection is driven by the buoyancy forces. And the density variation is determined dynamically with the convection. Numerical simulation is carried out with different parameter values, intending to extrapolate numerical results for geophysical implications.

  11. Uranium in mantle processes

    International Nuclear Information System (INIS)

    Cortini, M.

    1984-01-01

    (1) Metasomatism is an effective process in the mantle. It controls the distribution of U, Th and Pb in the mantle before the onset of magma formation. (2) Radioactive disequilibria demonstrate that magma formation is an open-system very fast process in which Ra, U and Th are extracted in large amounts from a mantle source that is geochemically distinct from the mantle fraction from which the melt is formed. (3) Because the enrichment of U, Th and Ra in the magma is so fast, the concept of mineral-melt partition coefficient is not valid for these elements during magma formation. (4) Metasomatism seems to generally produce an increase in μ and a decrease in K of the metasomatized mantle region. (5) Magma formation at oceanic ridges and islands seems to generally produce a decrease in K, in its mantle source region. (6) The major source of U, Th, Ra and Pb in a magma probably is the metasomatic mantle component. Instead, the major source of Sr and Nd in a magma is the non-metasomatic, more 'refractory' mantle component. (7) This proposed model is testable. It predicts isotopic disequilibrium of Pb between coexisting minerals and whole rocks, and a correlation of Pb with Th isotopes. (author)

  12. Excisional biopsy, auxillary node dissection and definitive radiotherapy for Stages I and II breast cancer

    International Nuclear Information System (INIS)

    Danoff, B.F.; Pajak, T.F.; Solin, L.J.; Goodman, R.L.

    1985-01-01

    From 1977 to 1982, 189 patients with clinical Stage I and II breast cancer underwent excisional biopsy and auxillary node dissection followed by definitive radiotherapy at the University of Pennsylvania. One hundred and nine patients had T 1 lesions and 80 had T 2 lesions. Histologically negative nodes were found in 136 patients (72%) and histologically positive nodes in 53 patients. Median follow-up from the completion of radiotherapy was 26 months. The four year actuarial disease free survival is 82% for pathologic Stage I and 70% for pathologic Stage II. Cosmesis was judged to be good to excellent in 90% and fair in 9%. Complications included arm edema (7%), symptomatic pneumonitis (1%), rib fractures (1%), pericarditis (1%) and pleural effusion (1%). Primary radiotherapy for Stages I and II breast cancer produces a local-regional control rate of 95% and good to excellent cosmesis in 90% of the patients. While these results are preliminary, they compare favorably with other reported series

  13. Saturn V Second Stage (S-II) Ready for Static Test

    Science.gov (United States)

    1965-01-01

    Two workers are dwarfed by the five J-2 engines of the Saturn V second stage (S-II) as they make final inspections prior to a static test firing by North American Space Division. These five hydrogen -fueled engines produced one million pounds of thrust, and placed the Apollo spacecraft into earth orbit before departing for the moon. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  14. Regulatory activity based risk model identifies survival of stage II and III colorectal carcinoma.

    Science.gov (United States)

    Liu, Gang; Dong, Chuanpeng; Wang, Xing; Hou, Guojun; Zheng, Yu; Xu, Huilin; Zhan, Xiaohui; Liu, Lei

    2017-11-17

    Clinical and pathological indicators are inadequate for prognosis of stage II and III colorectal carcinoma (CRC). In this study, we utilized the activity of regulatory factors, univariate Cox regression and random forest for variable selection and developed a multivariate Cox model to predict the overall survival of Stage II/III colorectal carcinoma in GSE39582 datasets (469 samples). Patients in low-risk group showed a significant longer overall survival and recurrence-free survival time than those in high-risk group. This finding was further validated in five other independent datasets (GSE14333, GSE17536, GSE17537, GSE33113, and GSE37892). Besides, associations between clinicopathological information and risk score were analyzed. A nomogram including risk score was plotted to facilitate the utilization of risk score. The risk score model is also demonstrated to be effective on predicting both overall and recurrence-free survival of chemotherapy received patients. After performing Gene Set Enrichment Analysis (GSEA) between high and low risk groups, we found that several cell-cell interaction KEGG pathways were identified. Funnel plot results showed that there was no publication bias in these datasets. In summary, by utilizing the regulatory activity in stage II and III colorectal carcinoma, the risk score successfully predicts the survival of 1021 stage II/III CRC patients in six independent datasets.

  15. Non-Surgical Breast-Conserving Treatment (KORTUC-BCT Using a New Radiosensitization Method (KORTUC II for Patients with Stage I or II Breast Cancer

    Directory of Open Access Journals (Sweden)

    Yasuhiro Ogawa

    2015-11-01

    Full Text Available The purpose of the present study was to establish a non-surgical breast-conserving treatment (BCT using KORTUC II radiosensitization treatment. A new radiosensitizing agent containing 0.5% hydrogen peroxide and 0.83% sodium hyaluronate (a CD44 ligand has been developed for intra-tumoral injection into various tumors. This new method, named KORTUC II, was approved by our local ethics committee for the treatment of breast cancer and metastatic lymph nodes. A total of 72 early-stage breast cancer patients (stage 0, 1 patient; stage I, 23; stage II, 48 were enrolled in the KORTUC II trial after providing fully informed consent. The mean age of the patients was 59.7 years. A maximum of 6 mL (usually 3 mL for tumors of less than approximately 3 cm in diameter of the agent was injected into breast tumor tissue twice a week under ultrasonographic guidance. For radiotherapy, hypofraction radiotherapy was administered using a tangential fields approach including an ipsilateral axillary region and field-in-field method; the energy level was 4 MV, and the total radiation dose was 44 Gy administered as 2.75 Gy/fraction. An electron boost of 3 Gy was added three times. Treatment was well tolerated with minimal adverse effects in all 72 patients. No patients showed any significant complications other than mild dermatitis. A total of 24 patients under 75 years old with stage II breast cancer underwent induction chemotherapy (EC and/or taxane prior to KORTUC II treatment, and 58 patients with estrogen receptor-positive tumors also received hormonal therapy following KORTUC II. The mean duration of follow-up as of the end of September 2014 was 51.1 months, at which time 68 patients were alive without any distant metastases. Only one patient had local recurrence and died of cardiac failure at 6.5 years. Another one patient had bone metastases. For two of the 72 patients, follow-up ended after several months following KORTUC II treatment. In conclusion, non

  16. Ezrin expression combined with MSI status in prognostication of stage II colorectal cancer.

    Directory of Open Access Journals (Sweden)

    Khadija Slik

    Full Text Available Currently used factors predicting disease recurrence in stage II colorectal cancer patients are not optimal for risk stratification. Thus, new biomarkers are needed. In this study the applicability of ezrin protein expression together with MSI status and BRAF mutation status were tested in predicting disease outcome in stage II colorectal cancer. The study population consisted of 173 stage II colorectal cancer patients. Paraffin-embedded cancer tissue material from surgical specimens was used to construct tissue microarrays (TMAs with next-generation technique. The TMA-slides were subjected to following immunohistochemical stainings: MLH1, MSH2, MSH6, PMS2, ezrin and anti-BRAF V600E antibody. The staining results were correlated with clinicopathological variables and survival. In categorical analysis, high ezrin protein expression correlated with poor disease-specific survival (p = 0.038. In univariate analysis patients having microsatellite instabile / low ezrin expression tumors had a significantly longer disease-specific survival than patients having microsatellite stable / high ezrin expression tumors (p = 0.007. In multivariate survival analysis, the presence of BRAF mutation was associated to poor overall survival (p = 0.028, HR 3.29, 95% CI1.14-9.54. High ezrin protein expression in patients with microsatellite stable tumors was linked to poor disease-specific survival (p = 0.01, HR 5.68, 95% CI 1.53-21.12. Ezrin protein expression is a promising biomarker in estimating the outcome of stage II colorectal cancer patients. When combined with microsatellite status its ability in predicting disease outcome is further improved.

  17. Fulvestrant and/or Anastrozole in Treating Postmenopausal Patients With Stage II-III Breast Cancer Undergoing Surgery

    Science.gov (United States)

    2018-04-06

    Estrogen Receptor-positive Breast Cancer; HER2-negative Breast Cancer; Invasive Ductal Breast Carcinoma; Invasive Lobular Breast Carcinoma; Recurrent Breast Cancer; Stage II Breast Cancer; Stage IIIA Breast Cancer; Stage IIIB Breast Cancer; Stage IIIC Breast Cancer

  18. Treatment results of radiotherapy for medically inoperable stage I/II non-small cell lung cancer

    International Nuclear Information System (INIS)

    Zhang Li; Wang Lvhua; Zhang Hongxing; Chen Dongfu; Xiao Zefen; Wang Mei; Feng Qinfu; Liang Jun; Zhou Zongmei; Ou Guangfei; Lv Jima; Yin Weibo

    2008-01-01

    Objective: To retrospectively analyze treatment results of radiotherapy for medically inoperable stage I/II non-small cell lung cancer. Methods: Between Jan. 2000 and Dec. 2005, fifty-eight such patients were enrolled into the database analysis, including 37 with clinical stage I and 21 with stage II disease. Fifty patients received radiotherapy alone and eight with radiotherapy and chemotherapy. Forty- three patients were treated with 3-D conformal radiotherapy (3D-CRT) and 15 with conventional radiotherapy. Results: The 1-, 2- and 3-year overall survival rates were 85%, 54% and 30%, and the median survival time was 26.2 months for the whole group. The corresponding figures were 88%, 60%, 36% and 30.8 months for cancer-specific survival; 84%, 64%, 31% and 30.8 months for Stage I disease; 81%, 47%, 28% and 18.8 months for Stage II disease; 95%, 57%, 33% and 30.8 months for 3D-CRT group and 53%, 44%, 24% and 15.3 months for conventional radiotherapy group. By logrank test, tumor volume, pneumonitis of Grade II or higher and weight loss more than 5% showed statistically significant impact on overall survival. Tumor volume was the only independent prognostic factor in Cox multivariable regression. Pneumonitis and esophagitis of Grade II or higher were 16% and 2%, respectively. Age and lung function before treatment had a significant relationship with pneumonitis. Failure included the local recurrence (33%) and distant metastasis (21%). There was no difference between the treatment modalities and failure sites. Conclusions: For medically inoperable early stage non-small cell lung cancer patients, tumor volume is the most important prognostic factor for overall survival. The conformal radiotherapy marginally improves the survival. The age and pulmonary function are related to the incidence of treatment induced pneumonitis. (authors)

  19. Evaluation of Oral Hygiene in Patients with Generalized Periodontitis of II Degree and Stage II Hypertension

    Directory of Open Access Journals (Sweden)

    Tetiana Vivcharenko

    2016-12-01

    Conclusions. The level of oral hygiene in patients of both groups was low due to incorrect selection of personal hygiene products or their untimely replacement. In patients with generalized periodontitis of II degree and stage II hypertension, the level of oral hygiene was lower than in somatically healthy persons: the worse status of oral cavity hygiene – the more pronounced changes in the periodontal tissues. We can suppose that high blood pressure affects the status of the oral cavity, creates a higher risk and exacerbates the periodontal diseases.

  20. Trace element distribution in peridotite xenoliths from Tok, SE Siberian craton: A record of pervasive, multi-stage metasomatism in shallow refractory mantle

    Science.gov (United States)

    Ionov, Dmitri A.; Chazot, Gilles; Chauvel, Catherine; Merlet, Claude; Bodinier, Jean-Louis

    2006-03-01

    Spinel peridotite xenoliths in alkali basalts at Tok, SE Siberian craton range from fertile lherzolites to harzburgites and wehrlites; olivine-rich (70-84%) rocks are dominant. REE patterns in the lherzolites range from nearly flat for fertile rocks (14-17% cpx) to LREE-enriched; the enrichments are positively correlated with modal olivine, consistent with high-permeability of olivine-rich rocks during melt percolation. Clinopyroxene in olivine-rich Tok peridotites typically has convex-upward trace element patterns (La/Nd PM 1); the LREE-enrichments are positively correlated with phosphorus abundances and are mainly hosted by accessory phosphates and P-rich cryptocrystalline materials. In addition to apatite, some Tok xenoliths contain whitlockite (an anhydrous, halogen-poor and Na-Mg-rich phosphate), which is common in meteorites and lunar rocks, but has not been reported from any terrestrial mantle samples. Some olivine-rich peridotites have generations of clinopyroxene with distinct abundances of Na, LREE, Sr and Zr. The mineralogical and trace element data indicate that the lithospheric mantle section represented by the xenoliths experienced a large-scale metasomatic event produced by upward migration of mafic silicate melts followed by percolation of low- T, alkali-rich melts and fluids. Chromatographic fractionation and fractional crystallisation of the melts close to the percolation front produced strong LREE-enrichments, which are most common in the uppermost mantle and are related to carbonate- and P 2O 5-rich derivatives of the initial melt. Reversal and gradual retreat of the percolation front during thermal relaxation to ambient geotherm ("retrograde" metasomatism) caused local migration and entrapment of small-volume residual fluids and precipitation of volatile-rich accessory minerals. A distinct metasomatic episode, which mainly produced "anhydrous" late-stage interstitial materials was concomitant with the alkali basaltic magmatism, which brought

  1. A rare case of breast carcinoma co-existing with axillary mantle cell lymphoma

    Directory of Open Access Journals (Sweden)

    Scally John

    2003-12-01

    Full Text Available Abstract Background Mantle cell lymphoma (MCL is a rare variety of non-Hodgkin's lymphoma which originates from CD5+ B-cell population in the mantle zones of lymphoid follicles. Coexistence of such tumours in the axillary lymph nodes with invasive breast cancers without prior history of adjuvant chemotherapy or radiotherapy has not been previously reported in literature. Case report We report a rare case of breast cancer co-existing with stage I mantle cell lymphoma of the ipsilateral axillary lymph node detected fortuitously by population screening. Conclusion Though some studies have tried to prove breast carcinomas and lymphomas to share a common molecular or viral link, more research needs to be done to establish whether such a link truly exists.

  2. Outcome of radiotherapy for localized stage I E and II E nasal NK/T cell lymphoma

    International Nuclear Information System (INIS)

    Jin Jing; Li Yexiong; Yao Bo; Fang Hui; Liu Xinfan; Zhou Liqiang; Lv Ning; Yu Zihao

    2006-01-01

    Objective: With the optimal therapy remains unclear for nasal NK/T cell lymphoma, the aim of this study is to analyze the outcome of radiotherapy as primary treatment for localized stage I E and II E diseases. Methods: Between January. 1983 and December 2003, 105 patients with stage I E and II E primary nasal NK/T cell lymphoma were retrospectively reviewed. According to the Ann Arbor Staging System, there were 83 stage I E and 22 stage II E. Stage I E was subdivided into limited stage I E confined to the nasal cavity (37 patients), or extensive stage I E with an extension beyond the nasal cavity (46 patients). Thirty-one patients received radiotherapy alone. Thirty-four patients were treated with radiotherapy followed by 2-4 cycles of chemotherapy. Thirty-seven patients were treated with chemotherapy followed by radiotherapy and 3 with chemotherapy alone. Of 83 patients with stage I E disease, 26 were primarily treated with radiotherapy alone, 30 with. radiotherapy followed by chemotherapy, and 27 with chemotherapy followed by radiotherapy. Results: The five-year overall survival (OS) and progression-free survival rates (PIS) for all patients was 71% and 59%, respectively. The 5-year OS for stage I E and stage II E was 78% and 46% (P<0.01), while the 5-year PFS for stage I E and stage II E was 63% and 40%, respectively (P<0.01). Patients with limited stage I E had a better OS and PFS than those with extensive stage I E, with 5-year OS and PFS of 82% and 80% versus 75% and 45%, respectively. Complete response (CR) was achieved in 91 (87%) patients after radiotherapy and/or chemotherapy. Initial radiotherapy resulted in a superior CR as compared to initial chemotherapy, with 54 of 65 (83%) patients achieving CR with initial radiotherapy, versus only 8 of 40 (20%) with initial chemotherapy. For 102 patients who received radiotherapy with or without chemotherapy, the outcome of primary, treatment with radiotherapy alone was compared to that of CMT. Five-year OS and

  3. Treatment results of Stage I and II oral tongue cancer with interstitial brachytherapy: maximum tumor thickness is prognostic of nodal metastasis

    International Nuclear Information System (INIS)

    Matsuura, Kanji; Hirokawa, Yutaka; Fujita, Minoru; Akagi, Yukio; Ito, Katsuhide

    1998-01-01

    Purpose: To evaluate the prognostic importance of T classification and maximum tumor thickness (MTT) on the treatment results of Stage I and II oral tongue cancer treated with interstitial brachytherapy. Methods and Materials: Between January 1981 and December 1993, 173 cases were eligible for this retrospective analysis. Of 173 patients, 75 were classified as Stage I and 98 as Stage II: maximum tumor length ranged from 6 to 40 mm. MTT, which ranged from 2 to 38 mm, was measured with ultrasonography and/or palpation. Brachytherapy was performed with iridium hairpins or radium needles following external irradiation in 66 patients, or exclusively in 107 patients. Results: The 5-year local recurrence rates were Stage I, 7%; Stage II, 22%; MTT < 8 mm, 8%; and MTT ≥ 8 mm, 28%. The 5-year regional recurrence rates were Stage I, 15%; Stage II, 29%; MTT < 8 mm, 18%; and MTT ≥ 8 mm, 31%, respectively. The 5-year local recurrence rates of the patients with Stage I and MTT < 8 mm of the brachytherapy only group were significantly better than those of Stage II and MTT ≥ 8 mm (5% and 6% vs. 16% and 24%). The 5-year regional recurrence rates of the patients with Stage I and MTT < 8 mm of the brachytherapy-only group were significantly better than those of Stage II and MTT ≥ 8 mm (14% and 16% vs. 34% and 46%). There was no significant difference in the 5-year regional recurrence rates between the two groups of Stage I and Stage II, MTT < 8 mm. However, there was a significant difference in the 5-year regional recurrence rates between the two groups of MTT ≥ 8 mm (p < 0.005). Conclusions: For patients with Stage I and II oral tongue cancer, tumor thickness as well as T classification were prognostic for nodal metastasis and prognosis. Patients with MTT ≥ 8 mm are more likely to fail in the neck region. These findings suggest that MTT should be considered along with T stage in determining strategies for Stage I and II oral tongue cancer

  4. Adjuvant chemotherapy is associated with improved survival in patients with stage II colon cancer.

    Science.gov (United States)

    Casadaban, Leigh; Rauscher, Garth; Aklilu, Mebea; Villenes, Dana; Freels, Sally; Maker, Ajay V

    2016-11-15

    The role of adjuvant chemotherapy in patients with stage II colon cancer remains to be elucidated and its use varies between patients and institutions. Currently, clinical guidelines suggest discussing adjuvant chemotherapy for patients with high-risk stage II disease in the absence of conclusive randomized controlled trial data. To further investigate this relationship, the objective of the current study was to determine whether an association exists between overall survival (OS) and adjuvant chemotherapy in patients stratified by age and pathological risk features. Data from the National Cancer Data Base were analyzed for demographics, tumor characteristics, management, and survival of patients with stage II colon cancer who were diagnosed from 1998 to 2006 with survival information through 2011. Pearson Chi-square tests and binary logistic regression were used to analyze disease and demographic data. Survival analysis was performed with the log-rank test and Cox proportional hazards regression modeling. Propensity score weighting was used to match cohorts. Among 153,110 patients with stage II colon cancer, predictors of receiving chemotherapy included age clinically relevant OS was associated with the receipt of adjuvant chemotherapy in all patient subgroups regardless of high-risk tumor pathologic features (poor or undifferentiated histology, colon cancer evaluated to date, improved OS was found to be associated with adjuvant chemotherapy regardless of treatment regimen, patient age, or high-risk pathologic risk features. Cancer 2016;122:3277-3287. © 2016 American Cancer Society. © 2016 American Cancer Society.

  5. Breast cancer relapse stage I and II

    International Nuclear Information System (INIS)

    Perez Braojos, Ines; Diaz Gestoso, Yadira; Franco Odio, Sonia; Samuel Gonzalez, Victor

    2009-01-01

    Breast cancer has always been the most common malignancy in women and is the leading cause of death in women, study relapses Stages I and II therapeutic guidelines applied in the service Mastology the 1985 - 1989, was our first objective, the database used was Clinical history, which gave us all the material necessary, treatments were: In tumors up to 3 cm node-conserving surgery plus treatment N0 with ionizing radiation on the breast tangential C0G0 in tumors greater than 3 cm or less with N1 was modified radical mastectomy according to node status for the study of the part and the receiver adjuvant treatment conducted. (Author)

  6. Sr-Nd evidence of paleoproterozoic mantle metasomatism in the lithospheric mantle beneath northeastern Brazil

    International Nuclear Information System (INIS)

    Hollanda, M.H.B.M.; Pimentel, M.M.; Jardim de Sa, E.F

    2001-01-01

    In the Borborema Province (Northeastern Brazil), the Brasiliano/Pan-African Cycle is expressed by two prominent and penecontemporaneous features: a regional network of transcurrent shear zones and associated large granitoid magmatism. The Rio Grande do Norte Domain (RGND) is an orogenic domain located in the northeastern part of the Borborema Province, and its tectonic evolution is largely related to the Brasiliano orogeny (ca. 600 Ma). This domain includes four major tectonic terranes, which are represented by two metavolcanosedimentary sequences Jaguaribe-Oeste Potiguar and Serido belts, and its gneiss-migmatite Paleoproterozoic basement the Rio Piranhas and Sao Jose de Campestre massifs (Brito Neves et al., 2000). The rocks have been metamorphosed up to the amphibolite facies. Its deformational fabrics are dominated by extensive Brasiliano ductile shear zones displaying predominantly dextral transcurrent kinematic regime. These structures control the emplacement of several Neoproterozoic granitoid intrusions which are made up mainly by porphyritic granitoid suites with subalkaline monzonitic affinity. These occur as isolated plutons of various sizes or as composite intrusions, associated with basic-tointermediate suites. In the latter case, magma mingling and mixing attest that these are contemporaneous igneous suites. Several features suggest coeval relationships with granitic magmas, possibly implying processes such as assimilation or magma mixing. Field evidence of magma mixing include (i) extensive capture of feldspar phenocrysts of the acid mushes by the basic magmas, (ii) common presence of globular to ellipsoidal basic enclaves in the granitic suites, (iii) stockwork-type features consisting of felsic material veining through a diorite host and (iv) syn-plutonic basic dykes intruded into the porphyritic granites (Jardim de S 1994). In this work, Rb-Sr and Sm-Nd isotopic compositions from six distinct basic-to-intermediate suites were investigated to

  7. Dynamical geochemistry of the mantle

    Directory of Open Access Journals (Sweden)

    G. F. Davies

    2011-09-01

    Full Text Available The reconciliation of mantle chemistry with the structure of the mantle inferred from geophysics and dynamical modelling has been a long-standing problem. This paper reviews three main aspects. First, extensions and refinements of dynamical modelling and theory of mantle processing over the past decade. Second, a recent reconsideration of the implications of mantle heterogeneity for melting, melt migration, mantle differentiation and mantle segregation. Third, a recent proposed shift in the primitive chemical baseline of the mantle inferred from observations of non-chondritic 142Nd in the Earth. It seems most issues can now be resolved, except the level of heating required to maintain the mantle's thermal evolution.

    A reconciliation of refractory trace elements and their isotopes with the dynamical mantle, proposed and given preliminary quantification by Hofmann, White and Christensen, has been strengthened by work over the past decade. The apparent age of lead isotopes and the broad refractory-element differences among and between ocean island basalts (OIBs and mid-ocean ridge basalts (MORBs can now be quantitatively accounted for with some assurance.

    The association of the least radiogenic helium with relatively depleted sources and their location in the mantle have been enigmatic. The least radiogenic helium samples have recently been recognised as matching the proposed non-chondritic primitive mantle. It has also been proposed recently that noble gases reside in a so-called hybrid pyroxenite assemblage that is the result of melt from fusible pods reacting with surrounding refractory peridotite and refreezing. Hybrid pyroxenite that is off-axis may not remelt and erupt at MORs, so its volatile constituents would recirculate within the mantle. Hybrid pyroxenite is likely to be denser than average mantle, and thus some would tend to settle in the D" zone at the base of the mantle, along with some old subducted

  8. Effect of anti-VEGF treatment on retinopathy of prematurity in Zone II Stage 3+

    Directory of Open Access Journals (Sweden)

    Xiu-Mei Yang

    2018-04-01

    Full Text Available AIM: To evaluate the effect of intravitreal ranibizumab injection for retinopathy of prematurity (ROP in Zone II Stage 3+. METHODS: Data was collected for ROP patients with Zone II Stage 3+ who received intravitreal ranibizumab injections between October 2014 and Janu­ary 2017 at the Department of Ophthalmology in our hospital. No prior laser or other intravitreal treatment was done. Prior to the intervention and at each follow-up visit, fundus examination was performed. Gestational age at birth, sex, birth weight, ROP zone, ROP stage, post menstrual age (PMA at treatment, and follow-up pe­riod were recorded. The final clinical status of the retina was evaluated for each patient. The primary outcome mea­sures included ROP recurrences requiring re-treatment, complete or incomplete peripheral vascularization. RESULTS: Eighty-six eyes of 46 premature infants with Zone II Stage 3+ ROP were enrolled in the study. The mean gestational age at birth was 28.18±1.67 (range: 25 to 33wk and the mean birth weight was 1070.57±226.85 (range: 720.00 to 1650.00 g. The mean PMA at treatment was 38.32±2.99 (range: 32.29 to 46.00wk. Seventy-one eyes (82.56% were treated success­fully with intravitreal ranibizumab as monotherapy. Fifteen eyes (17.44% developed recurrent disease. The mean interval between the treatment and retreatment was 5.96±3.22 (range: 1.86 to 11.71wk. All eyes vascularized into zone III at the end of the study and among them 62 eyes (72.09% achieved complete vascu­larization. CONCLUSION: Intravitreal ranibizumab injection is an effective treatment in Zone II Stage 3+ ROP patients. More patients with longer follow-up duration are necessary to confirm the safety and efficacy of this treatment.

  9. Radiotherapeutic aspects of the treatment of adult patients with supradiaphragmatic Hodgkin's disease CS I/II. Pt. 1; Regarding the indications of primary and adjuvant radiotherapy. Fragen und Aspekte zur Radiotherapie bei erwachsenen Patienten mit lokalisierten supradiaphragmalen Stadien (CS I/II) eines Morbus Hodgkin. T. 1; Fragen und Aspekte zu den Indikationen einer primaeren und einer adjuvanten Radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Glanzmann, C. (Universitaetsspital, Klinik fuer Radio-Onkologie, Zurich (Switzerland)); Luetolf, U.M. (Universitaetsspital, Klinik fuer Radio-Onkologie, Zurich (Switzerland))

    1993-08-01

    Randomized studies of chemo- vs radiotherapy in patients with PS I/II A and some PS III A have shown conflicting results. Patients with supra-diaphragmatic Hodkin's disease and CS I/II can be subdivided according to radiotherapy as: 1. Patients with a very low or a low recurrence risk of approximately 10 to 20%: Patients less than 40 years old and CS I/II A NS/LP with less than three involved regions and no bulky mediastinal mass and an ESR below 30 mm. In the other patients, primary irradiation of an extended mantle field without a staging laparotomy is an acceptable primary treatment, achieving a recurrence-free survival rate of approximately 80%. Another option is a staging laparotomy with splenectomy and a mantle radiotherapy for PS I/II. Few groups prefer primary chemotherapy alone or some type of a reduced chemotherapy with lesser toxicity combined with localized radiotherapy and long-term observations of a larger group of patients after the last type of treatment have to confirm the excellent early results. 2. Patients with an intermediate recurrence risk of approximately 20 to 40%: Patients, who do not belong to group one or group 3. Patients less than 50 years old with CS I/II and an ESR less than 50 mm and without bulky mediastinal involvement and with one of the following signs: Three involved regions or MC or one B symptom. A patient with more than one of these signs or with two or three B symptoms should be classified in group 3. For these patients, we recommend staging laparotomy and radiotherapy if PS I/II or primary chemotherapy with or without radiotherapy of the involved regions. 3. Patients with a high recurrence risk (40% or higher): (Abstract Truncated)

  10. High clusterin expression correlates with a poor outcome in stage II colorectal cancers.

    LENUS (Irish Health Repository)

    Kevans, David

    2012-02-01

    The role of clusterin in tumor growth and progression remains unclear. Overexpression of cytoplasmic clusterin has been studied in aggressive colon tumors; however, no correlation between clusterin expression and survival in colorectal cancer has been identified to date. We assessed levels of clusterin expression in a group of stage II colorectal cancer patients to assess its utility as a prognostic marker. The study included 251 patients with stage II colorectal cancer. Tissue microarrays were constructed and immunohistochemistry done and correlated with clinical features and long term outcome. Dual immunofluorescence and confocal microscopy were used with terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling probes and clusterin antibody to assess the degree of co localization. Percentage epithelial cytoplasmic staining was higher in tumor compared with nonadjacent normal mucosa (P < 0.001). Within the stromal compartment, percentage cytoplamic staining and intensity was lower in tumor tissue compared with normal nonadjacent mucosa (P < or = 0.001). Survival was significantly associated with percentage epithelial cytoplasmic staining (P < 0.001), epithelial cytoplasmic staining intensity (P < 0.001), percentage stromal cytoplasmic staining (P = 0.002), and stromal cytoplasmic staining intensity (P < 0.001). Clusterin levels are associated with poor survival in stage II colorectal cancer.

  11. Mantle dynamics following supercontinent formation

    Science.gov (United States)

    Heron, Philip J.

    This thesis presents mantle convection numerical simulations of supercontinent formation. Approximately 300 million years ago, through the large-scale subduction of oceanic sea floor, continental material amalgamated to form the supercontinent Pangea. For 100 million years after its formation, Pangea remained relatively stationary, and subduction of oceanic material featured on its margins. The present-day location of the continents is due to the rifting apart of Pangea, with supercontinent dispersal being characterized by increased volcanic activity linked to the generation of deep mantle plumes. The work presented here investigates the thermal evolution of mantle dynamics (e.g., mantle temperatures and sub-continental plumes) following the formation of a supercontinent. Specifically, continental insulation and continental margin subduction are analyzed. Continental material, as compared to oceanic material, inhibits heat flow from the mantle. Previous numerical simulations have shown that the formation of a stationary supercontinent would elevate sub-continental mantle temperatures due to the effect of continental insulation, leading to the break-up of the continent. By modelling a vigorously convecting mantle that features thermally and mechanically distinct continental and oceanic plates, this study shows the effect of continental insulation on the mantle to be minimal. However, the formation of a supercontinent results in sub-continental plume formation due to the re-positioning of subduction zones to the margins of the continent. Accordingly, it is demonstrated that continental insulation is not a significant factor in producing sub-supercontinent plumes but that subduction patterns control the location and timing of upwelling formation. A theme throughout the thesis is an inquiry into why geodynamic studies would produce different results. Mantle viscosity, Rayleigh number, continental size, continental insulation, and oceanic plate boundary evolution are

  12. The Effect of Simvastatin on Breast Cancer Cell Growth in Women With Stage I-II Breast Cancer

    Science.gov (United States)

    2018-03-02

    Invasive Breast Carcinoma; Stage I Breast Cancer AJCC v7; Stage IA Breast Cancer AJCC v7; Stage IB Breast Cancer AJCC v7; Stage II Breast Cancer AJCC v6 and v7; Stage IIA Breast Cancer AJCC v6 and v7; Stage IIB Breast Cancer AJCC v6 and v7

  13. Heat transfer correlations in mantle tanks

    DEFF Research Database (Denmark)

    Furbo, Simon; Knudsen, Søren

    2005-01-01

    on calculations with a CFD-model, which has earlier been validated by means of experiments. The CFD-model is used to determine the heat transfer between the solar collector fluid in the mantle and the walls surrounding the mantle in all levels of the mantle as well as the heat transfer between the wall...... transfer correlations are suitable as input for a detailed simulation model for mantle tanks. The heat transfer correlations determined in this study are somewhat different from previous reported heat transfer correlations. The reason is that this study includes more mantle tank designs and operation......Small solar domestic hot water systems are best designed as low flow systems based on vertical mantle tanks. Theoretical investigations of the heat transfer in differently designed vertical mantle tanks during different operation conditions have been carried out. The investigations are based...

  14. 2-Hexadecynoic acid inhibits plasmodial FAS-II enzymes and arrests erythrocytic and liver stage Plasmodium infections.

    Science.gov (United States)

    Tasdemir, Deniz; Sanabria, David; Lauinger, Ina L; Tarun, Alice; Herman, Rob; Perozzo, Remo; Zloh, Mire; Kappe, Stefan H; Brun, Reto; Carballeira, Néstor M

    2010-11-01

    Acetylenic fatty acids are known to display several biological activities, but their antimalarial activity has remained unexplored. In this study, we synthesized the 2-, 5-, 6-, and 9-hexadecynoic acids (HDAs) and evaluated their in vitro activity against erythrocytic (blood) stages of Plasmodium falciparum and liver stages of Plasmodium yoelii infections. Since the type II fatty acid biosynthesis pathway (PfFAS-II) has recently been shown to be indispensable for liver stage malaria parasites, the inhibitory potential of the HDAs against multiple P. falciparum FAS-II (PfFAS-II) elongation enzymes was also evaluated. The highest antiplasmodial activity against blood stages of P. falciparum was displayed by 5-HDA (IC(50) value 6.6 μg/ml), whereas the 2-HDA was the only acid arresting the growth of liver stage P. yoelii infection, in both flow cytometric assay (IC(50) value 2-HDA 15.3 μg/ml, control drug atovaquone 2.5 ng/ml) and immunofluorescence analysis (IC(50) 2-HDA 4.88 μg/ml, control drug atovaquone 0.37 ng/ml). 2-HDA showed the best inhibitory activity against the PfFAS-II enzymes PfFabI and PfFabZ with IC(50) values of 0.38 and 0.58 μg/ml (IC(50) control drugs 14 and 30 ng/ml), respectively. Enzyme kinetics and molecular modeling studies revealed valuable insights into the binding mechanism of 2-HDA on the target enzymes. All HDAs showed in vitro activity against Trypanosoma brucei rhodesiense (IC(50) values 3.7-31.7 μg/ml), Trypanosoma cruzi (only 2-HDA, IC(50) 20.2 μg/ml), and Leishmania donovani (IC(50) values 4.1-13.4 μg/ml) with generally low or no significant toxicity on mammalian cells. This is the first study to indicate therapeutic potential of HDAs against various parasitic protozoa. It also points out that the malarial liver stage growth inhibitory effect of the 2-HDA may be promoted via PfFAS-II enzymes. The lack of cytotoxicity, lipophilic nature, and calculated pharmacokinetic properties suggests that 2-HDA could be a useful compound to

  15. 2-Hexadecynoic Acid Inhibits Plasmodial FAS-II Enzymes and Arrest Erythrocytic and Liver Stage Plasmodium Infections

    Science.gov (United States)

    Tasdemir, Deniz; Sanabria, David; Lauinger, Ina L.; Tarun, Alice; Herman, Rob; Perozzo, Remo; Zloh, Mire; Kappe, Stefan H.; Brun, Reto; Carballeira, Néstor M.

    2010-01-01

    Acetylenic fatty acids are known to display several biological activities, but their antimalarial activity has remained unexplored. In this study, we synthesized the 2-, 5-, 6-, and 9-hexadecynoic acids (HDAs) and evaluated their in vitro activity against erythrocytic (blood) stages of Plasmodium falciparum and liver stages of P. yoelii infections. Since the type II fatty acid biosynthesis pathway (PfFAS-II) has recently been shown to be indispensable for liver stage malaria parasites, the inhibitory potential of the HDAs against multiple P. falciparum FAS-II (PfFAS-II) elongation enzymes was also evaluated. The highest antiplasmodial activity against blood stages of P. falciparum was displayed by 5-HDA (IC50 value 6.6. μg/ml), whereas the 2-HDA was the only acid arresting the growth of liver stage P. yoelii infection, in both flow cytometric assay (IC50 value 2-HDA 15.3 μg/ml, control drug atovaquone 2.5 ng/ml) and immunofluorescense analysis (IC50 2-HDA 4.88 μg/ml, control drug atovaquone 0.37 ng/ml). 2-HDA showed the best inhibitory against the PfFAS-II enzymes PfFabI and PfFabZ with IC50 values of 0.38 and 0.58 μg/ml (IC50 control drugs 14 and 30 ng/ml) respectively. Enzyme kinetics and molecular modeling studies revealed valuable insights into the binding mechanism of 2-HDA on the target enzymes. All HDAs showed in vitro activity against Trypanosoma brucei rhodesiense (IC50 values 3.7–31.7 μg/ml), Trypanosoma cruzi (only 2-HDA, IC50 20.2 μg/ml), and Leishmania donovani (IC50 values 4.1–13.4 μg/ml) with generally low or no significant toxicity on mammalian cells. This is the first study to indicate therapeutic potential of HDAs against various parasitic protozoa. It also points out that the malarial liver stage growth inhibitory effect of the 2-HDA may be promoted via PfFAS-II enzymes. The lack of cytotoxicity, lipophilic nature and calculated pharmacokinetic properties suggest that 2-HDA could be a useful compound to study the interaction of fatty

  16. A Thermal Evolution Model of the Earth Including the Biosphere, Continental Growth and Mantle Hydration

    Science.gov (United States)

    Höning, D.; Spohn, T.

    2014-12-01

    By harvesting solar energy and converting it to chemical energy, photosynthetic life plays an important role in the energy budget of Earth [2]. This leads to alterations of chemical reservoirs eventually affecting the Earth's interior [4]. It further has been speculated [3] that the formation of continents may be a consequence of the evolution life. A steady state model [1] suggests that the Earth without its biosphere would evolve to a steady state with a smaller continent coverage and a dryer mantle than is observed today. We present a model including (i) parameterized thermal evolution, (ii) continental growth and destruction, and (iii) mantle water regassing and outgassing. The biosphere enhances the production rate of sediments which eventually are subducted. These sediments are assumed to (i) carry water to depth bound in stable mineral phases and (ii) have the potential to suppress shallow dewatering of the underlying sediments and crust due to their low permeability. We run a Monte Carlo simulation for various initial conditions and treat all those parameter combinations as success which result in the fraction of continental crust coverage observed for present day Earth. Finally, we simulate the evolution of an abiotic Earth using the same set of parameters but a reduced rate of continental weathering and erosion. Our results suggest that the origin and evolution of life could have stabilized the large continental surface area of the Earth and its wet mantle, leading to the relatively low mantle viscosity we observe at present. Without photosynthetic life on our planet, the Earth would be geodynamical less active due to a dryer mantle, and would have a smaller fraction of continental coverage than observed today. References[1] Höning, D., Hansen-Goos, H., Airo, A., Spohn, T., 2014. Biotic vs. abiotic Earth: A model for mantle hydration and continental coverage. Planetary and Space Science 98, 5-13. [2] Kleidon, A., 2010. Life, hierarchy, and the

  17. Prognostic impact of interhospital variation in adjuvant chemotherapy for patients with Stage II/III colorectal cancer: a nationwide study.

    Science.gov (United States)

    Arakawa, K; Kawai, K; Tanaka, T; Hata, K; Sugihara, K; Nozawa, H

    2018-05-12

    Clinical guidelines recommend adjuvant chemotherapy for high-risk patients with Stage II-III colorectal cancer. However, chemotherapeutic administration rates differ significantly between hospitals. We assessed the prognostic benefit of adjuvant chemotherapy in patients with Stage IIb/c colorectal cancer, and the prognostic impact of interhospital variations in the administration of adjuvant chemotherapy for Stage II-III colorectal cancer. We conducted a multicentre, retrospective study of 17 757 patients with Stage II-III colorectal cancer treated between 1997 and 2008 in 23 hospitals in Japan. Hospitals were classified as high-rate (rate > 42.8%) or low-rate (rate ≤ 42.8%), chemotherapy prescribing clinics. The 5-year overall survival (OS) of patients with Stage II-III colorectal cancer receiving adjuvant chemotherapy was significantly higher than for those not receiving adjuvant chemotherapy (85.7% vs 79.2%, P colorectal cancer (both P colorectal cancer who received adjuvant chemotherapy, with patients who were treated in hospitals with high adjuvant chemotherapy rates demonstrating better prognoses. Colorectal Disease © 2018 The Association of Coloproctology of Great Britain and Ireland.

  18. Evolution of the earliest mantle caused by the magmatism-mantle upwelling feedback: Implications for the Moon and the Earth

    Science.gov (United States)

    Ogawa, M.

    2017-12-01

    The two most important agents that cause mantle evolution are magmatism and mantle convection. My earlier 2D numerical models of a coupled magmatism-mantle convection system show that these two agents strongly couple each other, when the Rayleigh number Ra is sufficiently high: magmatism induced by a mantle upwelling flow boosts the upwelling flow itself. The mantle convection enhanced by this positive feedback (the magmatism-mantle upwelling, or MMU, feedback) causes vigorous magmatism and, at the same time, strongly stirs the mantle. I explored how the MMU feedback influences the evolution of the earliest mantle that contains the magma ocean, based on a numerical model where the mantle is hot and its topmost 1/3 is partially molten at the beginning of the calculation: The evolution drastically changes its style, as Ra exceeds the threshold for onset of the MMU feedback, around 107. At Ra 107, however, the mantle remains compositionally more homogeneous in spite of the widespread magmatism, and the deep mantle remains hotter than the shallow mantle, because of the strong convective stirring caused by the feedback. The threshold value suggests that the mantle of a planet larger than Mars evolves in a way substantially different from that in the Moon does. Indeed, in my earlier models, magmatism makes the early mantle compositionally stratified in the Moon, but the effects of strong convective stirring overwhelms that of magmatism to keep the mantle compositionally rather homogeneous in Venus and the Earth. The MMU feedback is likely to be a key to understanding why vestiges of the magma ocean are so scarce in the Earth.

  19. Early and long-term mantle processing rates derived from xenon isotopes

    Science.gov (United States)

    Mukhopadhyay, S.; Parai, R.; Tucker, J.; Middleton, J. L.; Langmuir, C. H.

    2015-12-01

    giant impact occurred 45-70 Myr after the start of the solar system. After the giant impact stage, the Pu-U-Xe system indicates that degassing of the planet via solid-state mantle convection and plate tectonics continued to liberate volatiles to the atmosphere and has led to between ~5-8 mantle turnovers over the age of the Earth.

  20. Identification of miRNAs associated with recurrence of stage II colorectal cancer

    DEFF Research Database (Denmark)

    Christensen, Lise Lotte; Tobiasen, Heidi; Schepeler, Troels

    2011-01-01

    Colorectal cancer (CRC) is one of the leading causes of cancer deaths. Twenty-five percent of the patients radically treated for a stage II CRC (no lymph node or distant metastasis) later develop recurrence and dies from the disease. MicroRNAs (miRNAs) are aberrantly expressed or mutated in human...... target prediction and transcript profiling. Initially, miRNA over-expression in HCT116 cells was followed by transcriptional profiling of transfected cells using GeneChip Human Exon 1.0 ST Arrays. Three in silico predicted miRNA targets showing differential mRNA expression upon miRNA up-regulation were...... cancers, and function either as tumour suppressors or oncogenes. Additionally, they also appear to have both diagnostic and prognostic significance. The aim of the present study was to identify miRNAs associated with recurrence of stage II CRC, followed up by an investigation of how these potential...

  1. Silica-enriched mantle sources of subalkaline picrite-boninite-andesite island arc magmas

    Science.gov (United States)

    Bénard, A.; Arculus, R. J.; Nebel, O.; Ionov, D. A.; McAlpine, S. R. B.

    2017-02-01

    Primary arc melts may form through fluxed or adiabatic decompression melting in the mantle wedge, or via a combination of both processes. Major limitations to our understanding of the formation of primary arc melts stem from the fact that most arc lavas are aggregated blends of individual magma batches, further modified by differentiation processes in the sub-arc mantle lithosphere and overlying crust. Primary melt generation is thus masked by these types of second-stage processes. Magma-hosted peridotites sampled as xenoliths in subduction zone magmas are possible remnants of sub-arc mantle and magma generation processes, but are rarely sampled in active arcs. Published studies have emphasised the predominantly harzburgitic lithologies with particularly high modal orthopyroxene in these xenoliths; the former characteristic reflects the refractory nature of these materials consequent to extensive melt depletion of a lherzolitic protolith whereas the latter feature requires additional explanation. Here we present major and minor element data for pristine, mantle-derived, lava-hosted spinel-bearing harzburgite and dunite xenoliths and associated primitive melts from the active Kamchatka and Bismarck arcs. We show that these peridotite suites, and other mantle xenoliths sampled in circum-Pacific arcs, are a distinctive peridotite type not found in other tectonic settings, and are melting residues from hydrous melting of silica-enriched mantle sources. We explore the ability of experimental studies allied with mantle melting parameterisations (pMELTS, Petrolog3) to reproduce the compositions of these arc peridotites, and present a protolith ('hybrid mantle wedge') composition that satisfies the available constraints. The composition of peridotite xenoliths recovered from erupted arc magmas plausibly requires their formation initially via interaction of slab-derived components with refractory mantle prior to or during the formation of primary arc melts. The liquid

  2. Low Expression of TBX4 Predicts Poor Prognosis in Patients with Stage II Pancreatic Ductal Adenocarcinoma

    Directory of Open Access Journals (Sweden)

    Meijuan Zong

    2011-08-01

    Full Text Available This study was designed to investigate the expression of the T-box transcription factor 4 (TBX4, a tumor biomarker that was previously identified by proteomics, in pancreatic ductal adenocarcinoma (PDAC and evaluate its clinical utility as a potential prognostic biomarkers for PDAC. The expression of TBX4 was detected in 77 stage II PDAC tumors by immunohistochemistry, and the results were analyzed with regard to clinicopathological characteristics and overall survival. Moreover, Tbx4 promoter methylation status in primary PDAC tumors and normal adjacent pancreas tissues was measured by bisulfite sequencing. Among 77 stage II PDAC tumors, 48 cases (62.3% expressed TBX4 at a high level. No significant correlation between TBX4 expression and other clinicopathological parameters, except tumor grade and liver metastasis recurrence, was found. The survival of patients with TBX4-high expression was significantly longer than those with TBX4-low expression (P = 0.010. In multivariate analysis, low TBX4 expression was an independent prognostic factor for overall survival in patients with stage II PDAC. TBX4 promoter methylation status was frequently observed in both PDAC and normal adjacent pancreas. We conclude that a low level of TBX4 expression suggests a worse prognosis for patients with stage II PDAC. Down-regulation of the TBX4 gene in pancreas is less likely to be regulated by DNA methylation.

  3. The Earth's mantle and geoneutrinos

    International Nuclear Information System (INIS)

    Fiorentini, Giovanni; Fogli, Gian Luigi; Lisi, Eligio; Mantovani, Fabio; Rotunno, Anna Maria; Xhixha, Gerti

    2013-01-01

    The KamLAND and Borexino experiments have observed, each at ∼4σ level, signals of electron antineutrinos produced in the decay chains of thorium and uranium in the Earth's crust and mantle (Th and U geoneutrinos). Various pieces of geochemical and geophysical information allow an estimation of the crustal geoneutrino flux components with relatively small uncertainties. The mantle component may then be inferred by subtracting the estimated crustal flux from the measured total flux. We find that crust-subtracted signals show hints of a residual mantle component, emerging at ∼2.4σ level by combining the KamLAND and Borexino data. The inferred mantle flux, slightly favoring scenarios with relatively high Th and U abundances, within ∼1σ uncertainties is comparable to the predictions from recent mantle models

  4. Identification and Construction of Combinatory Cancer Hallmark-Based Gene Signature Sets to Predict Recurrence and Chemotherapy Benefit in Stage II Colorectal Cancer.

    Science.gov (United States)

    Gao, Shanwu; Tibiche, Chabane; Zou, Jinfeng; Zaman, Naif; Trifiro, Mark; O'Connor-McCourt, Maureen; Wang, Edwin

    2016-01-01

    Decisions regarding adjuvant therapy in patients with stage II colorectal cancer (CRC) have been among the most challenging and controversial in oncology over the past 20 years. To develop robust combinatory cancer hallmark-based gene signature sets (CSS sets) that more accurately predict prognosis and identify a subset of patients with stage II CRC who could gain survival benefits from adjuvant chemotherapy. Thirteen retrospective studies of patients with stage II CRC who had clinical follow-up and adjuvant chemotherapy were analyzed. Respective totals of 162 and 843 patients from 2 and 11 independent cohorts were used as the discovery and validation cohorts, respectively. A total of 1005 patients with stage II CRC were included in the 13 cohorts. Among them, 84 of 416 patients in 3 independent cohorts received fluorouracil-based adjuvant chemotherapy. Identification of CSS sets to predict relapse-free survival and identify a subset of patients with stage II CRC who could gain substantial survival benefits from fluorouracil-based adjuvant chemotherapy. Eight cancer hallmark-based gene signatures (30 genes each) were identified and used to construct CSS sets for determining prognosis. The CSS sets were validated in 11 independent cohorts of 767 patients with stage II CRC who did not receive adjuvant chemotherapy. The CSS sets accurately stratified patients into low-, intermediate-, and high-risk groups. Five-year relapse-free survival rates were 94%, 78%, and 45%, respectively, representing 60%, 28%, and 12% of patients with stage II disease. The 416 patients with CSS set-defined high-risk stage II CRC who received fluorouracil-based adjuvant chemotherapy showed a substantial gain in survival benefits from the treatment (ie, recurrence reduced by 30%-40% in 5 years). The CSS sets substantially outperformed other prognostic predictors of stage 2 CRC. They are more accurate and robust for prognostic predictions and facilitate the identification of patients with stage

  5. [Combination of NAFLD Fibrosis Score and liver stiffness measurement for identification of moderate fibrosis stages (II & III) in non-alcoholic fatty liver disease].

    Science.gov (United States)

    Drolz, Andreas; Wehmeyer, Malte; Diedrich, Tom; Piecha, Felix; Schulze Zur Wiesch, Julian; Kluwe, Johannes

    2018-01-01

    Non-alcoholic fatty liver disease (NAFLD) has become one of the most frequent causes of chronic liver disease. Currently, therapeutic options for NAFLD patients are limited, but new pharmacologic agents are being investigated in the course of clinical trials. Because most of these studies are focusing on patients with fibrosis stages II and III (according to Kleiner), non-invasive identification of patients with intermediate fibrosis stages (II and III) is of increasing interest. Evaluation of NAFLD Fibrosis Score (NFS) and liver stiffness measurement (LSM) for prediction of fibrosis stages II/III. Patients with histologically confirmed NAFLD diagnosis were included in the study. All patients underwent a clinical and laboratory examination as well as a LSM prior to liver biopsy. Predictive value of NFS and LSM with respect to identification of fibrosis stages II/III was assessed. 134 NAFLD patients were included and analyzed. Median age was 53 (IQR 36 - 60) years, 55 patients (41 %) were female. 82 % of our patients were overweight/obese with typical aspects of metabolic syndrome. 84 patients (66 %) had liver fibrosis, 42 (50 %) advanced fibrosis. LSM and NFS correlated with fibrosis stage (r = 0.696 and r = 0.685, respectively; p stages II/III. If both criteria were met, probability of fibrosis stage II/III was 61 %. If none of the two criteria was met, chance for fibrosis stage II/III was only 6 % (negative predictive value 94 %). Combination of LSM and NFS enables identification of patients with significant probability of fibrosis stage II/III. Accordingly, these tests, especially in combination, may be a suitable screening tool for fibrosis stages II/III in NAFLD. The use of these non-invasive methods might also help to avoid unnecessary biopsies. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Mantle wedge serpentinization effects on slab dips

    Directory of Open Access Journals (Sweden)

    Eh Tan

    2017-01-01

    Full Text Available The mechanical coupling between a subducting slab and the overlying mantle wedge is an important factor in controlling the subduction dip angle and the flow in mantel wedge. This paper investigates the role of the amount of mantle serpentinization on the subduction zone evolution. With numerical thermos-mechanical models with elasto-visco-plastic rheology, we vary the thickness and depth extent of mantle serpentinization in the mantle wedge to control the degree of coupling between the slab and mantle wedge. A thin serpentinized mantle layer is required for stable subduction. For models with stable subduction, we find that the slab dip is affected by the down-dip extent and the mantle serpentinization thickness. A critical down-dip extent exists in mantle serpentinization, determined by the thickness of the overriding lithosphere. If the down-dip extent does not exceed the critical depth, the slab is partially coupled to the overriding lithosphere and has a constant dip angle regardless of the mantle serpentinization thickness. However, if the down-dip extent exceeds the critical depth, the slab and the base of the overriding lithosphere would be separated and decoupled by a thick layer of serpentinized peridotite. This allows further slab bending and results in steeper slab dip. Increasing mantle serpentinization thickness will also result in larger slab dip. We also find that with weak mantle wedge, there is no material flowing from the asthenosphere into the serpentinized mantle wedge. All of these results indicate that serpentinization is an important ingredient when studying the subduction dynamics in the mantle wedge.

  7. Plerixafor and Filgrastim For Mobilization of Donor Peripheral Blood Stem Cells Before A Donor Peripheral Blood Stem Cell Transplant in Treating Patients With Hematologic Malignancies

    Science.gov (United States)

    2017-06-26

    Accelerated Phase Chronic Myelogenous Leukemia; Adult Acute Lymphoblastic Leukemia in Remission; Adult Acute Myeloid Leukemia in Remission; Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities; Adult Acute Myeloid Leukemia With Inv(16)(p13;q22); Adult Acute Myeloid Leukemia With t(15;17)(q22;q12); Adult Acute Myeloid Leukemia With t(16;16)(p13;q22); Adult Acute Myeloid Leukemia With t(8;21)(q22;q22); Atypical Chronic Myeloid Leukemia, BCR-ABL Negative; Blastic Phase Chronic Myelogenous Leukemia; Chronic Phase Chronic Myelogenous Leukemia; de Novo Myelodysplastic Syndromes; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Myelodysplastic/Myeloproliferative Neoplasm, Unclassifiable; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Adult Burkitt Lymphoma; Noncontiguous Stage II Adult Diffuse Large Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Noncontiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Noncontiguous Stage II Adult Lymphoblastic Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Mantle Cell Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Previously Treated Myelodysplastic Syndromes; Recurrent Adult Acute Lymphoblastic Leukemia; Recurrent Adult Acute Myeloid Leukemia; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Hodgkin Lymphoma; Recurrent Adult Immunoblastic Large Cell Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular

  8. Mantle Convection on Modern Supercomputers

    Science.gov (United States)

    Weismüller, J.; Gmeiner, B.; Huber, M.; John, L.; Mohr, M.; Rüde, U.; Wohlmuth, B.; Bunge, H. P.

    2015-12-01

    Mantle convection is the cause for plate tectonics, the formation of mountains and oceans, and the main driving mechanism behind earthquakes. The convection process is modeled by a system of partial differential equations describing the conservation of mass, momentum and energy. Characteristic to mantle flow is the vast disparity of length scales from global to microscopic, turning mantle convection simulations into a challenging application for high-performance computing. As system size and technical complexity of the simulations continue to increase, design and implementation of simulation models for next generation large-scale architectures is handled successfully only in an interdisciplinary context. A new priority program - named SPPEXA - by the German Research Foundation (DFG) addresses this issue, and brings together computer scientists, mathematicians and application scientists around grand challenges in HPC. Here we report from the TERRA-NEO project, which is part of the high visibility SPPEXA program, and a joint effort of four research groups. TERRA-NEO develops algorithms for future HPC infrastructures, focusing on high computational efficiency and resilience in next generation mantle convection models. We present software that can resolve the Earth's mantle with up to 1012 grid points and scales efficiently to massively parallel hardware with more than 50,000 processors. We use our simulations to explore the dynamic regime of mantle convection and assess the impact of small scale processes on global mantle flow.

  9. Thrombocytosis portends adverse prognostic significance in patients with stage II colorectal carcinoma

    DEFF Research Database (Denmark)

    Guo, Tianhua; Krzystanek, Marcin; Szallasi, Zoltan Imre

    2014-01-01

    of the 78 patients (6.4%) with stage II cancer showed thrombocytosis, and four of these patients showed early recurrence and/or metastatic disease, resulting in shortened survival (they died within one year after surgery). The incidence of thrombocytosis increased to 12.2% and 20.6%, respectively...

  10. Thyroid dysfunction after mantle irradiation of Hodgkin's disease patients

    International Nuclear Information System (INIS)

    Khoo, V.S.; Liew, K.H.; Crennan, E.C.; D'Costa, I.M.; Quong, G.

    1998-01-01

    Thyroid dysfunction can develop in patients with Hodgkin's disease who are treated with mantle irradiation. During the period 1970-89, the records of 320 patients who received mantle irradiation and who had thyroid function tests (TFT) were retrospectively reviewed. The median age was 30 years (range, 7-69 years). The median mantle and thyroid dose was 36 Gy (range, 30-40 Gy) and 39.8 Gy (range, 32-65 Gy), respectively. Overall thyroid dysfunction was present in 39% of the patients. Clinical hypothyroidism was seen in 10% and biochemical hypothyroidism was noted in 25%. Hyperthyroidism was found in 4% of patients. Thyroid nodules had developed in six patients (2%), of which those in four patients were malignant. Age, sex, histological subtype, stage of disease, dose, Iymphangiogram and treatment with chemotherapy were not significant factors in the development of thyroid dysfunction. The narrow dose range prevented adequate analysis of dose effect. The results indicate that the incidence of thyroid abnormalities is high enough to warrant regular TFT assessment with pre-irradiation levels and follow-up testing for life because the development of abnormalities can occur many years later. Thyroid examination should form part of the routine follow-up examination and any abnormality should be promptly investigated. Copyright (1998) Blackwell Science Pty Ltd

  11. Identification of 42 Genes Linked to Stage II Colorectal Cancer Metastatic Relapse

    Directory of Open Access Journals (Sweden)

    Rabeah A. Al-Temaimi

    2016-04-01

    Full Text Available Colorectal cancer (CRC is one of the leading causes of cancer mortality. Metastasis remains the primary cause of CRC death. Predicting the possibility of metastatic relapse in early-stage CRC is of paramount importance to target therapy for patients who really need it and spare those with low-potential of metastasis. Ninety-six stage II CRC cases were stratified using high-resolution array comparative genomic hybridization (aCGH data based on a predictive survival algorithm and supervised clustering. All genes included within the resultant copy number aberrations were each interrogated independently at mRNA level using CRC expression datasets available from public repositories, which included 1820 colon cancers, and 167 normal colon tissues. Reduced mRNA expression driven by copy number losses and increased expression driven by copy number gains revealed 42 altered transcripts (29 reduced and 13 increased transcripts associated with metastatic relapse, short disease-free or overall survival, and/or epithelial to mesenchymal transition (EMT. Resultant genes were classified based on gene ontology (GO, which identified four functional enrichment groups involved in growth regulation, genomic integrity, metabolism, and signal transduction pathways. The identified 42 genes may be useful for predicting metastatic relapse in stage II CRC. Further studies are necessary to validate these findings.

  12. Role of Adjuvant Radiotherapy for Stage II Thymoma After Complete Tumor Resection

    International Nuclear Information System (INIS)

    Chen Yidong; Feng Qinfu; Lu Haizhen; Mao Yousheng; Zhou Zongmei; Ou Guangfei; Wang Mei; Zhao Jun; Zhang Hongxing; Xiao Zefen; Chen Dongfu; Liang Jun; Zhai Yirui; Wang Luhua; He Jie

    2010-01-01

    Purpose: To determine whether patients with Masaoka stage II thymoma benefit from adjuvant radiation therapy after complete tumor resection. Methods and Materials: A total of 107 patients with stage II thymoma who underwent complete resection of their tumors between September 1964 and October 2006 were retrospectively analyzed. Sixty-six patients were treated with adjuvant radiotherapy, and 41 patients received surgery alone. Results: Eight patients (7.5%) had a relapse of their disease, including two patients (4.5%) who had surgery alone, and 6 patients (9.5%) who had adjuvant radiation therapy. Disease-free survival rates at 5 and 10 years were 92.3% and 82.6%, respectively, for the surgery-plus-radiation group, and 97.6% and 93.1%, respectively, for the group that underwent surgery alone (p = 0.265). Disease-specific survival rates at 5 and 10 years were 96.4% and 89.3%, respectively, for the surgery-plus-radiation group and 97.5% and 97.5% for the surgery group (p = 0.973). On univariate analysis, patients with type B3 thymomas had the lowest disease-free survival rates among all subtypes (p = 0.001), and patients with large thymomas (>7 cm) had lower disease-specific survival rates than those with small tumors (<7 cm) (p = 0.017). On multivariate analysis, histological type (type B3) thymoma was a significant independent prognostic factor. Conclusions: Adjuvant radiotherapy after complete tumor resection for patients with stage II thymoma did not significantly reduce recurrence rates or improve survival rates. Histological type (type B3) thymoma was a significant independent prognostic factor. Further investigation should be carried out using a multicenter randomized or controlled study.

  13. The latest geodynamics in Asia: Synthesis of data on volcanic evolution, lithosphere motion, and mantle velocities in the Baikal-Mongolian region

    Directory of Open Access Journals (Sweden)

    Sergei Rasskazov

    2017-07-01

    Full Text Available From a synthesis of data on volcanic evolution, movement of the lithosphere, and mantle velocities in the Baikal-Mongolian region, we propose a comprehensive model for deep dynamics of Asia that assumes an important role of the Gobi, Baikal, and North Transbaikal transition-layer melting anomalies. This layer was distorted by lower-mantle fluxes at the beginning of the latest geodynamic stage (i.e. in the early late Cretaceous due to avalanches of slab material that were stagnated beneath the closed fragments of the Solonker, Ural-Mongolian paleoceans and Mongol-Okhotsk Gulf of Paleo-Pacific. At the latest geodynamic stage, Asia was involved in east–southeast movement, and the Pacific plate moved in the opposite direction with subduction under Asia. The weakened upper mantle region of the Gobi melting anomaly provided a counterflow connected with rollback in the Japan Sea area. These dynamics resulted in the formation of the Honshu-Korea flexure of the Pacific slab. A similar weakened upper mantle region of the North Transbaikal melting anomaly was associated with the formation of the Hokkaido-Amur flexure of the Pacific slab, formed due to progressive pull-down of the slab material into the transition layer in the direction of the Pacific plate and Asia convergence. The early–middle Miocene structural reorganization of the mantle processes in Asia resulted in the development of upper mantle low-velocity domains associated with the development of rifts and orogens. We propose that extension at the Baikal Rift was caused by deviator flowing mantle material, initiated under the moving lithosphere in the Baikal melting anomaly. Contraction at the Hangay orogen was created by facilitation of the tectonic stress transfer from the Indo-Asian interaction zone due to the low-viscosity mantle in the Gobi melting anomaly.

  14. Alternative Dosing of Exemestane Before Surgery in Treating Postmenopausal Patients With Stage 0-II Estrogen Positive Breast Cancer

    Science.gov (United States)

    2018-04-09

    Estrogen Receptor Positive; Postmenopausal; Stage 0 Breast Cancer AJCC v6 and v7; Stage I Breast Cancer AJCC v7; Stage IA Breast Cancer AJCC v7; Stage IB Breast Cancer AJCC v7; Stage II Breast Cancer AJCC v6 and v7; Stage IIA Breast Cancer AJCC v6 and v7; Stage IIB Breast Cancer AJCC v6 and v7

  15. [Analysis of prognostic factors after radical resection in 628 patients with stage II or III colon cancer].

    Science.gov (United States)

    Qin, Qiong; Yang, Lin; Zhou, Ai-ping; Sun, Yong-kun; Song, Yan; DU, Feng; Wang, Jin-wan

    2013-03-01

    To analyze the clinicopathologic factors related to recurrence and metastasis of stage II or III colon cancer after radical resection. The clinical and pathological data of 628 patients with stage II or III colon cancer after radical resection from Jan. 2005 to Dec. 2008 in our hospital were retrospectively reviewed and analyzed. The overall recurrence and metastasis rate was 28.5% (179/628). The 5-year disease-free survival (DFS) rate was 70.3% and 5-year overall survival (OS) rate was 78.5%. Univariate analysis showed that age, smoking intensity, depth of tumor invasion, lymph node metastasis, TNM stage, gross classification, histological differentiation, blood vessel tumor embolus, tumor gross pathology, multiple primary tumors, preoperative and postoperative serum concentration of CEA and CA19-9, and the regimen of adjuvant chemotherapy were correlated to recurrence and metastasis of colon cancer after radical resection. Multivariate analysis showed that regional lymph node metastasis, TNM stage, the regimen of postoperative adjuvant chemotherapy, and preoperative serum concentration of CEA and CA19-9 were independent factors affecting the prognosis of colon cancer patients. Regional lymph node metastasis, TNM stage, elevated preoperative serum concentration of CEA and CA19-9, the regimen of postoperative adjuvant chemotherapy with single fluorouracil type drug are independent risk factors of recurrence and metastasis in patients with stage II-III colon cancer after radical resection.

  16. Seismic Imaging of Mantle Plumes

    Science.gov (United States)

    Nataf, Henri-Claude

    The mantle plume hypothesis was proposed thirty years ago by Jason Morgan to explain hotspot volcanoes such as Hawaii. A thermal diapir (or plume) rises from the thermal boundary layer at the base of the mantle and produces a chain of volcanoes as a plate moves on top of it. The idea is very attractive, but direct evidence for actual plumes is weak, and many questions remain unanswered. With the great improvement of seismic imagery in the past ten years, new prospects have arisen. Mantle plumes are expected to be rather narrow, and their detection by seismic techniques requires specific developments as well as dedicated field experiments. Regional travel-time tomography has provided good evidence for plumes in the upper mantle beneath a few hotspots (Yellowstone, Massif Central, Iceland). Beneath Hawaii and Iceland, the plume can be detected in the transition zone because it deflects the seismic discontinuities at 410 and 660 km depths. In the lower mantle, plumes are very difficult to detect, so specific methods have been worked out for this purpose. There are hints of a plume beneath the weak Bowie hotspot, as well as intriguing observations for Hawaii. Beneath Iceland, high-resolution tomography has just revealed a wide and meandering plume-like structure extending from the core-mantle boundary up to the surface. Among the many phenomena that seem to take place in the lowermost mantle (or D''), there are also signs there of the presence of plumes. In this article I review the main results obtained so far from these studies and discuss their implications for plume dynamics. Seismic imaging of mantle plumes is still in its infancy but should soon become a turbulent teenager.

  17. Mantle refertilization and magmatism in old orogenic regions: The role of late-orogenic pyroxenites

    Science.gov (United States)

    France, Lydéric; Chazot, Gilles; Kornprobst, Jacques; Dallai, Luigi; Vannucci, Riccardo; Grégoire, Michel; Bertrand, Hervé; Boivin, Pierre

    2015-09-01

    Pyroxenites and garnet pyroxenites are mantle heterogeneities characterized by a lower solidus temperature than the enclosing peridotites; it follows that they are preferentially involved during magma genesis. Constraining their origin, composition, and the interactions they underwent during their subsequent evolution is therefore essential to discuss the sources of magmatism in a given area. Pyroxenites could represent either recycling of crustal rocks in mantle domains or mantle originated rocks (formed either by olivine consuming melt-rock reactions or by crystal fractionation). Petrological and geochemical (major and trace elements, Sr-Nd and O isotopes) features of xenoliths from various occurrences (French Massif-Central, Jordan, Morocco and Cameroon) show that these samples represent cumulates crystallized during melt percolation at mantle conditions. They formed in mantle domains at pressures of 1-2 GPa during post-collisional magmatism (possibly Hercynian for the French Massif-Central, and Panafrican for Morocco, Jordan and Cameroon). The thermal re-equilibration of lithospheric domains, typical of the late orogenic exhumation stages, is also recorded by the samples. Most of the samples display a metasomatic overprint that may be either inherited or likely linked to the recent volcanic activity that occurred in the investigated regions. The crystallization of pyroxenites during late orogenic events has implications for the subsequent evolution of the mantle domains. The presence of large amounts of mantle pyroxenites in old orogenic regions indeed imparts peculiar physical and chemical characteristics to these domains. Among others, the global solidus temperature of the whole lithospheric domain will be lowered; in turn, this implies that old orogenic regions are refertilized zones where magmatic activity would be enhanced.

  18. Breast carcinoma conservative treatment. Stages I and II; Tratamento conservador do carcinoma mamario. Estadios I e II

    Energy Technology Data Exchange (ETDEWEB)

    Monti, C.R.

    1990-12-31

    From 1981 to 1988, 265 patients with breast cancer stages I and II (UICC-1987), were evaluated after conservative treatment with quadrantectomy plus axillectomy, radiotherapy and chemotherapy. After surgical treatment, the patients were submitted to radiation therapy in the breast. One hundred and fifty six (58,8%) patients were submitted to adjuvant chemotherapy. The median clinical follow-up period was 42.8 months with a minimum of 24 and a maximum of 99 months. Six (2,3%) patients presented local recurrence and 48 (18,1%) presented distant metastasis. After five years the total survival rate was 89,7% and the disease free survival rate was 75% in the same period. The study did not show significant differences among the clinical stages classified after surgery and the use of adjuvant chemotherapy did not influence the results of the many stages. (author). 194 refs, 33 figs, 6 tabs.

  19. Breast carcinoma conservative treatment. Stages I and II; Tratamento conservador do carcinoma mamario. Estadios I e II

    Energy Technology Data Exchange (ETDEWEB)

    Monti, C R

    1991-12-31

    From 1981 to 1988, 265 patients with breast cancer stages I and II (UICC-1987), were evaluated after conservative treatment with quadrantectomy plus axillectomy, radiotherapy and chemotherapy. After surgical treatment, the patients were submitted to radiation therapy in the breast. One hundred and fifty six (58,8%) patients were submitted to adjuvant chemotherapy. The median clinical follow-up period was 42.8 months with a minimum of 24 and a maximum of 99 months. Six (2,3%) patients presented local recurrence and 48 (18,1%) presented distant metastasis. After five years the total survival rate was 89,7% and the disease free survival rate was 75% in the same period. The study did not show significant differences among the clinical stages classified after surgery and the use of adjuvant chemotherapy did not influence the results of the many stages. (author). 194 refs, 33 figs, 6 tabs.

  20. Mantle-cell lymphoma.

    Science.gov (United States)

    Barista, I; Romaguera, J E; Cabanillas, F

    2001-03-01

    During the past decade, mantle-cell lymphoma has been established as a new disease entity. The normal counterparts of the cells forming this malignant lymphoma are found in the mantle zone of the lymph node, a thin layer surrounding the germinal follicles. These cells have small to medium-sized nuclei, are commonly indented or cleaved, and stain positively with CD5, CD20, cyclin D1, and FMC7 antibodies. Because of its morphological appearance and a resemblance to other low-grade lymphomas, many of which grow slowly, this lymphoma was initially thought to be an indolent tumour, but its natural course was not thoroughly investigated until the 1990s, when the BCL1 oncogene was identified as a marker for this disease. Mantle-cell lymphoma is a discrete entity, unrelated to small lymphocytic or small-cleaved-cell lymphomas.

  1. Water in the Cratonic Mantle: Insights from FTIR Data on Lac De Gras Xenoliths (Slave Craton, Canada)

    Science.gov (United States)

    Peslier, Anne H.; Brandon, Alan D.; Schaffer, Lillian Aurora; O'Reilly, Suzanne Yvette; Griffin, William L.; Morris, Richard V.; Graff, Trevor G.; Agresti, David G.

    2014-01-01

    The mantle lithosphere beneath the cratonic part of continents is the deepest (> 200 km) and oldest (>2-3 Ga) on Earth, remaining a conundrum as to how these cratonic roots could have resisted delamination by asthenospheric convection over time. Water, or trace H incorporated in mineral defects, could be a key player in the evolution of continental lithosphere because it influences melting and rheology of the mantle. Mantle xenoliths from the Lac de Gras kimberlite in the Slave craton were analyzed by FTIR. The cratonic mantle beneath Lac de Gras is stratified with shallow (water contents extending to higher values than those from the shallow ones. The FTIR spectra of olivines from the shallow samples have more prominent Group II OH bands compared to the olivines from the deep samples, consistent with a more oxidized mantle environment. The range of olivine water content is similar to that observed in Kaapvaal craton peridotites at the same depths (129-184 km) but does not extend to as high values as those from Udachnaya (Siberian craton). The Slave, Kaapvaal and Siberian cratons will be compared in terms of water content distribution, controls and role in cratonic root longevity.

  2. Large-scale compositional heterogeneity in the Earth's mantle

    Science.gov (United States)

    Ballmer, M.

    2017-12-01

    Seismic imaging of subducted Farallon and Tethys lithosphere in the lower mantle has been taken as evidence for whole-mantle convection, and efficient mantle mixing. However, cosmochemical constraints point to a lower-mantle composition that has a lower Mg/Si compared to upper-mantle pyrolite. Moreover, geochemical signatures of magmatic rocks indicate the long-term persistence of primordial reservoirs somewhere in the mantle. In this presentation, I establish geodynamic mechanisms for sustaining large-scale (primordial) heterogeneity in the Earth's mantle using numerical models. Mantle flow is controlled by rock density and viscosity. Variations in intrinsic rock density, such as due to heterogeneity in basalt or iron content, can induce layering or partial layering in the mantle. Layering can be sustained in the presence of persistent whole mantle convection due to active "unmixing" of heterogeneity in low-viscosity domains, e.g. in the transition zone or near the core-mantle boundary [1]. On the other hand, lateral variations in intrinsic rock viscosity, such as due to heterogeneity in Mg/Si, can strongly affect the mixing timescales of the mantle. In the extreme case, intrinsically strong rocks may remain unmixed through the age of the Earth, and persist as large-scale domains in the mid-mantle due to focusing of deformation along weak conveyor belts [2]. That large-scale lateral heterogeneity and/or layering can persist in the presence of whole-mantle convection can explain the stagnation of some slabs, as well as the deflection of some plumes, in the mid-mantle. These findings indeed motivate new seismic studies for rigorous testing of model predictions. [1] Ballmer, M. D., N. C. Schmerr, T. Nakagawa, and J. Ritsema (2015), Science Advances, doi:10.1126/sciadv.1500815. [2] Ballmer, M. D., C. Houser, J. W. Hernlund, R. Wentzcovitch, and K. Hirose (2017), Nature Geoscience, doi:10.1038/ngeo2898.

  3. Ovarian Cancer Stage II

    Science.gov (United States)

    ... peritoneal cancer; the first panel (stage IIA) shows cancer inside both ovaries that has spread to the uterus and fallopian tube. The second panel (stage IIB) shows cancer inside both ovaries that has spread to the colon. The third ...

  4. A >100 Ma Mantle Geochemical Record: Retiring Mantle Plumes may be Premature

    Science.gov (United States)

    Konter, J. G.; Hanan, B. B.; Blichert-Toft, J.; Koppers, A. A.; Plank, T.; Staudigel, H.

    2006-12-01

    Hotspot volcanism has long been attributed to mantle plumes, but in recent years suggestions have been made that plate tectonic processes, such as extension, can account for all hotspot tracks. This explanation involves a profoundly less dynamic lower mantle, which justifies a critical evaluation before the plume model is dismissed. Such an evaluation has to involve a wide range of geochemical, geological, and geophysical techniques, broadly investigating the products of volcanism as well as the underlying lithosphere and mantle. We argue here that the combined geological record and geochemistry of intraplate volcanoes holds some important clues that help us decide between models of plume-like upwelling versus passive upwelling with lithospheric extension. The best of these integrated datasets can be obtained from the long seamount chains in the Pacific Ocean. A new combined dataset of trace element and isotopic compositions, along with modern 40Ar/39Ar ages from seamounts in the Gilbert Ridge, Tokelau chain, and West Pacific Seamount Province (WPSP) provides a record of current to Cretaceous volcanism in the South Pacific. We have reconstructed the eruptive locations of the seamounts using a range of absolute plate motion models, including some models with hotspot motion and others that use the Indo-Atlantic hotspot reference frame. Our results show that the backtracked locations consistently form clusters (300km radius) around the active ends of the Macdonald, Rurutu and Rarotonga hotspot chains, while closely matching their distinct C-HIMU and C-EM1 signatures. The oldest WPSP seamounts (older than 100 Ma) form the only exception and backtrack, with larger uncertainty, to north of Rarotonga. Therefore, the mantle currently underlying the Cook-Austral islands has produced volcanoes in three geochemically distinct areas for at least 100 m.y. Furthermore, we find the shortest mantle residence time, 0.6 Ga, for a source of mixed recycled DMM and an EM1-like

  5. Outcome for stage II and III rectal and colon cancer equally good after treatment improvement over three decades.

    Science.gov (United States)

    Fischer, Joern; Joern, Fischer; Hellmich, Gunter; Gunter, Hellmich; Jackisch, Thomas; Thomas, Jackisch; Puffer, Erik; Erik, Puffer; Zimmer, Jörg; Jörg, Zimmer; Bleyl, Dorothea; Dorothea, Bleyl; Kittner, Thomas; Thomas, Kittner; Witzigmann, Helmut; Helmut, Witzigmann; Stelzner, Sigmar; Sigmar, Stelzner

    2015-06-01

    This study aimed to investigate the outcome for stage II and III rectal cancer patients compared to stage II and III colonic cancer patients with regard to 5-year cause-specific survival (CSS), overall survival, and local and combined recurrence rates over time. This prospective cohort study identified 3,355 consecutive patients with adenocarcinoma of the colon or rectum and treated in our colorectal unit between 1981 and 2011, for investigation. The study was restricted to International Union Against Cancer (UICC) stages II and III. Postoperative mortality and histological incomplete resection were excluded, which left 995 patients with colonic cancer and 726 patients with rectal cancer for further analysis. Five-year CSS rates improved for colonic cancer from 65.0% for patients treated between 1981 and 1986 to 88.1% for patients treated between 2007 and 2011. For rectal cancer patients, the respective 5-year CSS rates improved from 53.4% in the first observation period to 89.8% in the second one. The local recurrence rate for rectal cancer dropped from 34.2% in the years 1981-1986 to 2.1% in the years 2007-2011. In the last decade of observation, prognosis for rectal cancer was equal to that for colon cancer (CSS 88.6 vs. 86.7%, p = 0.409). Survival of patients with colon and rectal cancer has continued to improve over the last three decades. After major changes in treatment strategy including introduction of total mesorectal excision and neoadjuvant (radio)chemotherapy, prognosis for stage II and III rectal cancer is at least as good as for stage II and III colonic cancer.

  6. Mg-Fe Isotope Systems of Mantle Xenoliths: Constrains on the Evolution of Siberian Craton

    Science.gov (United States)

    An, Y.; Kiseeva, E. S.; Sobolev, N. V.; Zhang, Z.

    2017-12-01

    Mantle xenoliths bring to the surface a variety of lithologies (dunites, lherzolites, harzburgites, wehrlites, eclogites, pyroxenites, and websterites) and represent snapshots of the geochemical processes that occur deep within the Earth. Recent improvements in the precision of the MC-ICP-MS measurements have allowed us to expand the amount of data on Mg and Fe isotopes for mantle-derived samples. For instance, to constrain the isotopic composition of the Earth based on the study of spinel and garnet peridotites (An et al., 2017; Teng et al., 2010), to trace the origin and to investigate the isotopic fractionation mechanism during metamorphic process using cratonic or orogenic eclogites (Li et al., 2011; Wang et al., 2012) and to reveal the metasomatism-induced mantle heterogeneity by pyroxenites (Hu et al., 2016). Numerous multi-stage modification events and mantle layering are detected in the subcontinental lithospheric mantle under the Siberian craton (Ashchepkov et al., 2008a; Sobolev et al., 1975, etc). Combined analyses of Mg and Fe isotopic systems could provide new constraints on the formation and evolution of the ancient cratonic mantle. In order to better constrain the magnitude and mechanism of inter-mineral Mg and Fe isotopic fractionations at high temperatures, systematic studies of mantle xenoliths are needed. For example, theoretical calculations and natural samples measurements have shown that large equilibrium Mg isotope fractionations controlled by the difference in coordination number of Mg among minerals could exist (Huang et al., 2013; Li et al., 2011). Thus, the Mg isotope geothermometer could help us trace the evolution history of ancient cratons. In this study we present Mg and Fe isotopic data for whole rocks and separated minerals (clinopyroxene (cpx) and garnet (grt)) from different types of mantle xenoliths (garnet pyroxenites, eclogites, grospydites and garnet peridotites) from a number of kimberlite pipes in Siberian craton (Udachnaya

  7. Asymmetric three-dimensional topography over mantle plumes.

    Science.gov (United States)

    Burov, Evgueni; Gerya, Taras

    2014-09-04

    The role of mantle-lithosphere interactions in shaping surface topography has long been debated. In general, it is supposed that mantle plumes and vertical mantle flows result in axisymmetric, long-wavelength topography, which strongly differs from the generally asymmetric short-wavelength topography created by intraplate tectonic forces. However, identification of mantle-induced topography is difficult, especially in the continents. It can be argued therefore that complex brittle-ductile rheology and stratification of the continental lithosphere result in short-wavelength modulation and localization of deformation induced by mantle flow. This deformation should also be affected by far-field stresses and, hence, interplay with the 'tectonic' topography (for example, in the 'active/passive' rifting scenario). Testing these ideas requires fully coupled three-dimensional numerical modelling of mantle-lithosphere interactions, which so far has not been possible owing to the conceptual and technical limitations of earlier approaches. Here we present new, ultra-high-resolution, three-dimensional numerical experiments on topography over mantle plumes, incorporating a weakly pre-stressed (ultra-slow spreading), rheologically realistic lithosphere. The results show complex surface evolution, which is very different from the smooth, radially symmetric patterns usually assumed as the canonical surface signature of mantle upwellings. In particular, the topography exhibits strongly asymmetric, small-scale, three-dimensional features, which include narrow and wide rifts, flexural flank uplifts and fault structures. This suggests a dominant role for continental rheological structure and intra-plate stresses in controlling dynamic topography, mantle-lithosphere interactions, and continental break-up processes above mantle plumes.

  8. Water in Earth's mantle: Hydrogen analysis of mantle olivine, pyroxenes and garnet using the SIMS

    Science.gov (United States)

    Kurosawa, Masanori; Yurimoto, Hisayoshi; Sueno, Shigeho

    1993-01-01

    Hydrogen (or water) in the Earth's interior plays a key role in the evolution and dynamics of the planet. However, the abundance and the existence form of the hydrogen have scarcely been clear in practice. Hydrogen in the mantle was incorporated in the interior during the formation of the Earth. The incorporated hydrogen was hardly possible to concentrate locally inside the Earth considering its high mobility and high reactivity. The hydrogen, preferably, could be distributed homogeneously over the mantle and the core by the subsequent physical and chemical processes. Therefore, hydrogen in the mantle could be present in the form of trace hydrogen in nominally anhydrous mantle minerals. The hydrogen and the other trace elements in mantle olivines, orthopyroxenes, clinopyroxenes, and garnets were determined using secondary ion mass spectrometry (SIMS) for elucidating (1) the exact hydrogen contents, (2) the correlation between the hydrogen and the other trace elements, (3) the dependence of the hydrogen contents on the depth, and (4) the dependence of the whole rock water contents on the depth.

  9. Use of a combination of CEA and tumor budding to identify high-risk patients with stage II colon cancer.

    Science.gov (United States)

    Du, Changzheng; Xue, Weicheng; Dou, Fangyuan; Peng, Yifan; Yao, Yunfeng; Zhao, Jun; Gu, Jin

    2017-07-24

    High-risk patients with stage II colon cancer may benefit from adjuvant chemotherapy, but identifying this patient population can be difficult. We assessed the prognosis value for predicting tumor progression in patients with stage II colon cancer, of a panel of 2 biomarkers for colon cancer: tumor budding and preoperative carcinoembryonic antigen (CEA). Consecutive patients (N = 134) with stage II colon cancer who underwent curative surgery from 2000 to 2007 were included. Multivariate analysis was used to evaluate the association of CEA and tumor budding grade with 5-year disease-free survival (DFS). The prognostic accuracy of CEA, tumor budding grade and the combination of both (CEA-budding panel) was determined. The study found that both CEA and tumor budding grade were associated with 5-year DFS. The prognostic accuracy for disease progression was higher for the CEA-budding panel (82.1%) than either CEA (70.9%) or tumor budding grade (72.4%) alone. The findings indicate that the combination of CEA levels and tumor budding grade has greater prognostic value for identifying patients with stage II colon cancer who are at high-risk for disease progression, than either marker alone.

  10. A discussion for the evolution model of Pb isotope of the upper mantle in western Yunnan and its interpretation to the lead isotopic compositions of the regional alkali-rich porphyries and their related rocks

    International Nuclear Information System (INIS)

    Wu Kaixing; Hu Ruizhong; Bi Xianwu; Zhang Qian; Peng Jiantang

    2003-01-01

    Thirty Pb isotope data of the upper mantle in the area of western Yunnan have the similar trends with the Stacey-Kramers' two stage model growth curves but apparently deviate from it on the lead isotope composition programs, which may suggest Pb isotope of the upper mantle in the area of western Yunnan might have two stage evolution history though not fit very well to the Stacey-Kramers' two stage model growth curves. In this paper, a two-stage growth curves which can better fit the Pb isotope data was constructed based on the lead isotope data of the upper mantle in western Yunnan and the principle that Stacey and Kramers constructed the two-stage model and a reasonable interpretation was given to the lead isotopic compositions of the regional alkali-rich porphyries and their related rocks using the model. (authors)

  11. Thermal Stratification in Vertical Mantle Tanks

    DEFF Research Database (Denmark)

    Knudsen, Søren; Furbo, Simon

    2001-01-01

    It is well known that it is important to have a high degree of thermal stratification in the hot water storage tank to achieve a high thermal performance of SDHW systems. This study is concentrated on thermal stratification in vertical mantle tanks. Experiments based on typical operation conditions...... are carried out to investigate how the thermal stratification is affected by different placements of the mantle inlet. The heat transfer between the solar collector fluid in the mantle and the domestic water in the inner tank is analysed by CFD-simulations. Furthermore, the flow pattern in the vertical mantle...

  12. The Earth’s mantle before convection: Effects of magma oceans and the Moon (Invited)

    Science.gov (United States)

    Elkins-Tanton, L. T.; Smrekar, S. E.; Tobie, G.

    2009-12-01

    Studies of magma oceans indicate that planets obtain a gravitationally stable, compositionally differentiated mantle following solidification. This stable mantle results primarily from iron-magnesium partitioning during solidification, producing progressively iron-enriched mantle phases as solidification proceeds. Near the end of solidification, the dense solids will overturn to a stable configuration. The resulting differentiated mantle is stable from compositional density gradients that are significant enough to suppress thermal convection for up to hundreds of millions of years or longer, a scenario that proceeds self-consistently from physical and chemical principals, but is in contradiction with a previous image of a hot, turbulently convecting earliest terrestrial mantle. The isotopic range found in Martian meteorites indicates that its mantle differentiated in the first tens of millions of years of the solar system and has not been thoroughly remixed since. The specific isotopic range found on Mars is consistent with formation in a magma ocean. Based on the isotopic compositions of magmas, the Earth’s mantle is well mixed in comparison with the mantle of Mars. If the terrestrial planets experienced partial or whole magma oceans and thus began with stable mantles, resisting the onset of thermal convection and subsequent remixing, then why is Earth’s mantle well mixed? Two processes predicted to occur on the Earth, but not on the smaller Mars, may explain the divergent evolutions of these bodies. Here we will present model calculations for these two processes. First, we hypothesize that in the brief period that the Moon was very close to the Earth, it may have tidally heated Earth’s interior sufficiently to overcome its initial compositionally stable mantle, initiate active convection, and set the stage for the well-mixed mantle sampled today. Mars, conversely, may have cooled significantly before thermal convection began, allowing the formation of a

  13. Mechanical Stimulation in Preventing Bone Density Loss in Patients Undergoing Donor Stem Cell Transplant

    Science.gov (United States)

    2012-07-05

    Accelerated Phase Chronic Myelogenous Leukemia; Adult Acute Lymphoblastic Leukemia in Remission; Adult Acute Myeloid Leukemia in Remission; Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities; Adult Acute Myeloid Leukemia With Del(5q); Adult Acute Myeloid Leukemia With Inv(16)(p13;q22); Adult Acute Myeloid Leukemia With t(15;17)(q22;q12); Adult Acute Myeloid Leukemia With t(16;16)(p13;q22); Adult Acute Myeloid Leukemia With t(8;21)(q22;q22); Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative; Blastic Phase Chronic Myelogenous Leukemia; Chronic Eosinophilic Leukemia; Chronic Myelomonocytic Leukemia; Chronic Neutrophilic Leukemia; Chronic Phase Chronic Myelogenous Leukemia; de Novo Myelodysplastic Syndromes; Disseminated Neuroblastoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Myelodysplastic/Myeloproliferative Neoplasm, Unclassifiable; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Adult Burkitt Lymphoma; Noncontiguous Stage II Adult Diffuse Large Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Noncontiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Noncontiguous Stage II Adult Lymphoblastic Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Mantle Cell Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Plasma Cell Neoplasm; Poor Prognosis Metastatic Gestational Trophoblastic Tumor; Previously Treated Myelodysplastic Syndromes; Primary Myelofibrosis; Prolymphocytic Leukemia; Recurrent Adult Acute Lymphoblastic Leukemia; Recurrent Adult Acute Myeloid Leukemia; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved

  14. Platinum-group element contents of Karelian kimberlites: Implications for the PGE budget of the sub-continental lithospheric mantle

    Science.gov (United States)

    Maier, W. D.; O'Brien, H.; Peltonen, P.; Barnes, Sarah-Jane

    2017-11-01

    We present high-precision isotope dilution data for Os, Ir, Ru, Pt, Pd and Re in Group I and Group II kimberlites from the Karelian craton, as well as 2 samples of the Premier Group I kimberlite pipe from the Kaapvaal craton. The samples have, on average, 1.38 ppb Pt and 1.33 ppb Pd, with Pt/Pd around unity. These PGE levels are markedly lower, by as much as 80%, than those reported previously for kimberlites from South Africa, Brazil and India, but overlap with PGE results reported recently from Canadian kimberlites. Primitive-mantle-normalised chalcophile element patterns are relatively flat from Os to Pt, but Cu, Ni and, somewhat less so, Au are enriched relative to the PGE (e.g., Cu/Pd > 25.000). Pd/Ir ratios are 3,6 on average, lower than in most other mantle melts. The PGE systematics can be largely explained by two components, (i) harzburgite/lherzolite detritus of the SCLM with relatively high IPGE (Os-Ir-Ru)/PPGE (Rh-Pt-Pd) ratios, and (ii) a melt component that has high PPGE/IPGE ratios. By using the concentrations of iridium in the kimberlites as a proxy for the proportion of mantle detritus in the magma, we estimate that the analysed kimberlites contain 3-27% entrained and partially dissolved detritus from the sub-continental lithospheric mantle, consistent with previous estimates of kimberlites elsewhere (Tappe S. et al., 2016, Chem. Geol. 10.1016/j.chemgeo.2016.08.019).

  15. The prognostic value of microRNA-126 and microvessel density in patients with stage II colon cancer

    DEFF Research Database (Denmark)

    Hansen, Torben Frøstrup; Kjær-Frifeldt, Sanne; Morgenthaler, Søren

    2014-01-01

    BACKGROUND: Angiogenesis plays a pivotal role in malignant tumour growth and the metastatic process. We analysed the prognostic value of two angiogenesis parameters, microRNA-126 (miRNA-126) and microvessel density (MVD), in a population based cohort of patients operated for stage II colon cancer...... estimate was not associated with either RF-CSS, p = 0.49, or OS, p = 0.94.CONCLUSION: The current population based study of patients operated for stage II colon cancer demonstrated correlations between several prognostic unfavourable characteristics and miRNA-126 and argues for a possible prognostic impact...

  16. Changes of serum cortisol and plasma angiotensin-II (AT-II) levels in patients with open chest surgery during peri-operative stage

    International Nuclear Information System (INIS)

    Yu Yunyun; Tian Runhua; Zhao Huiyuan; Li Xiaoqin; Wang Ling

    2005-01-01

    Objective: To assess the systemic stress reaction in patients with open chest surgery through measurement of the changes of serum cortisol and plasma AT-II levels during peri-operative stage. Methods: Serum cortisol and plasma AT-II levels were measured with RIA in 35 patients underwent open chest surgery both before and after the operative procedure. Results: The serum level of cortisol and plasma levels of AT-II were significantly higher after operation than those before operation ( P < 0.05 ). Also, the systolic pressure and heart rate were increased significantly (P<0.05). The post-operative heart rate was significantly positively correlated with both cortisol and AT-II levels (P<0.05). Conclusion: Stress reaction is evident in patients after open chest surgery with increase of serum cortisol and plasma AT-II levels. The stress reaction, if excessive, should be properly dealt with. (authors)

  17. Archean crust-mantle geochemical differentiation

    Science.gov (United States)

    Tilton, G. R.

    Isotope measurements on carbonatite complexes and komatiites can provide information on the geochemical character and geochemical evolution of the mantle, including the sub-continental mantle. Measurements on young samples establish the validity of the method. These are based on Sr, Nd and Pb data from the Tertiary-Mesozoic Gorgona komatiite and Sr and Pb data from the Cretaceous Oka carbonatite complex. In both cases the data describe a LIL element-depleted source similar to that observed presently in MORB. Carbonatite data have been used to study the mantle beneath the Superior Province of the Canadian Shield one billion years (1 AE) ago. The framework for this investigation was established by Bell et al., who showed that large areas of the province appear to be underlain by LIL element-depleted mantle (Sr-85/Sr-86=0.7028) at 1 AE ago. Additionally Bell et al. found four complexes to have higher initial Sr ratios (Sr-87/Sr-86=0.7038), which they correlated with less depleted (bulk earth?) mantle sources, or possibly crustal contamination. Pb isotope relationships in four of the complexes have been studied by Bell et al.

  18. Archean crust-mantle geochemical differentiation

    Science.gov (United States)

    Tilton, G. R.

    1983-01-01

    Isotope measurements on carbonatite complexes and komatiites can provide information on the geochemical character and geochemical evolution of the mantle, including the sub-continental mantle. Measurements on young samples establish the validity of the method. These are based on Sr, Nd and Pb data from the Tertiary-Mesozoic Gorgona komatiite and Sr and Pb data from the Cretaceous Oka carbonatite complex. In both cases the data describe a LIL element-depleted source similar to that observed presently in MORB. Carbonatite data have been used to study the mantle beneath the Superior Province of the Canadian Shield one billion years (1 AE) ago. The framework for this investigation was established by Bell et al., who showed that large areas of the province appear to be underlain by LIL element-depleted mantle (Sr-85/Sr-86=0.7028) at 1 AE ago. Additionally Bell et al. found four complexes to have higher initial Sr ratios (Sr-87/Sr-86=0.7038), which they correlated with less depleted (bulk earth?) mantle sources, or possibly crustal contamination. Pb isotope relationships in four of the complexes have been studied by Bell et al.

  19. The last stage of Earth's formation: Increasing the pressure

    Science.gov (United States)

    Lock, S. J.; Stewart, S. T.; Mukhopadhyay, S.

    2017-12-01

    A range of high-energy, high-angular momentum (AM) giant impacts have been proposed as a potential trigger for lunar origin. High-energy, high-AM collisions create a previously unrecognized planetary object, called a synestia. Terrestrial synestias exceed the corotation limit for a rocky planet, forming an extended structure with a corotating inner region and disk-like outer region. We demonstrate that the internal pressures of Earth-like planets do not increase monotonically during the giant impact stage, but can vary substantially in response to changes in rotation and thermal state. The internal pressures in an impact-generated synestia are much lower than in condensed, slowly rotating planets of the same mass. For example, the core-mantle boundary (CMB) pressure can be as low as 60 GPa for a synestia with Earth mass and composition, compared to 136 GPa in the present-day Earth. The lower pressures are due to the low density and rapid rotation of the post-impact structure. After a high-AM Moon-forming impact, the internal pressures in the interior of the synestia would have increased to present-day Earth values in two stages: first by vapor condensation and second by removal of AM from the Earth during the tidal evolution of the Moon. The pressure evolution of the Earth has several implications. Metal-silicate equilibration after the impact would have occurred at much lower pressures than has previously been assumed. The observed moderately siderophile element abundances in the mantle may be consistent with equilibration at the bottom of a deep, lower-pressure magma ocean. In addition, the pressure at the CMB during cooling is coincident with, or lower than, the proposed intersection of liquid adiabats with the mantle liquidus. The mantle would hence freeze from the bottom up and there would be no basal magma ocean. The subsequent pressure increase and tidal heating due to the Moon's orbital evolution likely induces melting in the lowermost mantle. Increasing

  20. Salvage of relapse of patients with Hodgkin's disease in clinical stages I or II who were staged with laparotomy and initially treated with radiotherapy alone. A report from the international database on Hodgkin's disease

    DEFF Research Database (Denmark)

    Specht, L.; Horwich, A.; Ashley, S.

    1994-01-01

    patients in the International Database on Hodgkin's Disease who were initially in clinical Stages I or II, who were staged with laparotomy, and who relapsed after initial treatment with irradiation alone. Factors analyzed for outcome after first relapse included initial stage, age, sex, histology......PURPOSE: To analyze presentation variables that might indicate a high or low likelihood of success of the treatment of patients relapsing after initial radiotherapy of Hodgkin's disease in clinical Stages I or II who were staged with laparotomy. METHODS AND MATERIALS: Data were analyzed on 681...

  1. Dose-Escalated Robotic SBRT for Stage I-II Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Robert eMeier

    2015-04-01

    Full Text Available Abstract: Stereotactic body radiotherapy (SBRT is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I dose escalation should yield improved rates of cancer control; (II the unique radiobiology of prostate cancer favors hypofractionation and (III the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent organs, potentially reducing complications. This approach is also more convenient for patients, and is cheaper than intensity modulated radiotherapy (IMRT. Several external beam platforms are capable of delivering SBRT for early-stage prostate cancer, although most of the mature reported series have employed a robotic non-coplanar platform (i.e., CyberKnife. Several large studies report 5-year biochemical relapse rates which compare favorably to IMRT. Rates of late GU toxicity are similar to those seen with IMRT, and rates of late rectal toxicity may be less than with IMRT and low dose rate (LDR brachytherapy. Patient-reported quality of life (QOL outcomes appear similar to IMRT in the urinary domain. Bowel QOL may be less adversely affected by SBRT than with other radiation modalities. After five years of follow-up, SBRT delivered on a robotic platform is yielding outcomes at least as favorable as IMRT, and may be considered appropriate therapy for stage I-II prostate cancer.

  2. The role of plumes in mantle helium fluxes

    International Nuclear Information System (INIS)

    Kellogg, L.H.; Wasserburg, G.J.

    1990-01-01

    We present a simple model of 3 He and 4 He transport in the mantle using the appropriate rates of mass and species transfer and 4 He production. Previous workers have shown the presence of excess 3 He in hotspots such as Hawaii and Iceland and inferred that these hotspots tap a source with a higher 3 He/ 4 He ratio than the source region of mid-ocean ridge basalts (MORB). Hotspot ocean islands probably originate over upwelling plumes which carry material from the lower mantle to the upper mantle. Melting at hotspots and at mid-ocean ridges degasses the mantle of volatiles such as helium. The upper mantle is outgassed largely of helium due to melting at mid-ocean ridges and hotspots. We postulate that the excess 3 He seen in MORB originates in material that was carried from the lower mantle in plumes but not completely outgassed at hotspots. This helium is incoporated into the depleted upper mantle. Assuming that the upper mantle is in a quasi-steady-state with respect to helium, a simple model balancing 3 He and 4 He fluxes in the upper mantle indicates that the hotspots significantly outgas the lower mantle of 3 He. The concentration of 4 He in the plume source reservoir is 2-3 orders of magnitude lower than the concentration in carbonaceous chondrites. The residence time of helium in the upper mantle depends on the outgassing efficiency at hotspots, since the hotspots may outgas some upper mantle material which has been entrained in the plumes. The residence time of He in the upper mantle is about 1.4x10 9 yr. We conclude that the efficiency of outgassing of He from plumes is high and that the plumes dominate the present 3 He loss to the atmosphere. The 4 He in the less depleted layer of the mantle is not trapped ''primordial'' but is predominantly from in situ decay of U and Th in the depleted layer over ≅ 1.4x10 9 yr. The 4 He in the lower mantle is dominantly from in situ decay of U and Th over 4.4x10 9 yr. (orig./WL)

  3. Nd-isotopes in selected mantle-derived rocks and minerals and their implications for mantle evolution

    Science.gov (United States)

    Basu, A.R.; Tatsumoto, M.

    1980-01-01

    The Sm-Nd systematics in a variety of mantle-derived samples including kimberlites, alnoite, carbonatite, pyroxene and amphibole inclusions in alkali basalts and xenolithic eclogites, granulites and a pyroxene megacryst in kimberlites are reported. The additional data on kimberlites strengthen our earlier conclusion that kimberlites are derived from a relatively undifferentiated chondritic mantle source. This conclusion is based on the observation that the e{open}Nd values of most of the kimberlites are near zero. In contrast with the kimberlites, their garnet lherzolite inclusions show both time-averaged Nd enrichment and depletion with respect to Sm. Separated clinopyroxenes in eclogite xenoliths from the Roberts Victor kimberlite pipe show both positive and negative e{open}Nd values suggesting different genetic history. A whole rock lower crustal scapolite granulite xenolith from the Matsoku kimberlite pipe shows a negative e{open}Nd value of -4.2, possibly representative of the base of the crust in Lesotho. It appears that all inclusions, mafic and ultramafic, in kimberlites are unrelated to their kimberlite host. The above data and additional Sm-Nd data on xenoliths in alkali basalts, alpine peridotite and alnoite-carbonatites are used to construct a model for the upper 200 km of the earth's mantle - both oceanic and continental. The essential feature of this model is the increasing degree of fertility of the mantle with depth. The kimberlite's source at depths below 200 km in the subcontinental mantle is the most primitive in this model, and this primitive layer is also extended to the suboceanic mantle. However, it is clear from the Nd-isotopic data in the xenoliths of the continental kimberlites that above 200 km the continental mantle is distinctly different from their suboceanic counterpart. ?? 1980 Springer-Verlag.

  4. Numerical simulations of the mantle lithosphere delamination

    Science.gov (United States)

    Morency, C.; Doin, M.-P.

    2004-03-01

    Sudden uplift, extension, and increased igneous activity are often explained by rapid mechanical thinning of the lithospheric mantle. Two main thinning mechanisms have been proposed, convective removal of a thickened lithospheric root and delamination of the mantle lithosphere along the Moho. In the latter case, the whole mantle lithosphere peels away from the crust by the propagation of a localized shear zone and sinks into the mantle. To study this mechanism, we perform two-dimensional (2-D) numerical simulations of convection using a viscoplastic rheology with an effective viscosity depending strongly on temperature, depth, composition (crust/mantle), and stress. The simulations develop in four steps. (1) We first obtain "classical" sublithospheric convection for a long time period (˜300 Myr), yielding a slightly heterogeneous lithospheric temperature structure. (2) At some time, in some simulations, a strong thinning of the mantle occurs progressively in a small area (˜100 km wide). This process puts the asthenosphere in direct contact with the lower crust. (3) Large pieces of mantle lithosphere then quickly sink into the mantle by the horizontal propagation of a detachment level away from the "asthenospheric conduit" or by progressive erosion on the flanks of the delaminated area. (4) Delamination pauses or stops when the lithospheric mantle part detaches or when small-scale convection on the flanks of the delaminated area is counterbalanced by heat diffusion. We determine the parameters (crustal thicknesses, activation energies, and friction coefficients) leading to delamination initiation (step 2). We find that delamination initiates where the Moho temperature is the highest, as soon as the crust and mantle viscosities are sufficiently low. Delamination should occur on Earth when the Moho temperature exceeds ˜800°C. This condition can be reached by thermal relaxation in a thickened crust in orogenic setting or by corner flow lithospheric erosion in the

  5. Family Caregiver Palliative Care Intervention in Supporting Caregivers of Patients With Stage II-IV Gastrointestinal, Gynecologic, Urologic and Lung Cancers

    Science.gov (United States)

    2018-02-12

    Healthy Subject; Localized Transitional Cell Cancer of the Renal Pelvis and Ureter; Metastatic Transitional Cell Cancer of the Renal Pelvis and Ureter; Psychosocial Effects of Cancer and Its Treatment; Recurrent Bladder Cancer; Recurrent Cervical Cancer; Recurrent Colon Cancer; Recurrent Gastric Cancer; Recurrent Ovarian Epithelial Cancer; Recurrent Ovarian Germ Cell Tumor; Recurrent Pancreatic Cancer; Recurrent Rectal Cancer; Recurrent Renal Cell Cancer; Recurrent Transitional Cell Cancer of the Renal Pelvis and Ureter; Recurrent Urethral Cancer; Recurrent Uterine Sarcoma; Regional Transitional Cell Cancer of the Renal Pelvis and Ureter; Stage II Bladder Cancer; Stage II Renal Cell Cancer; Stage II Urethral Cancer; Stage IIA Cervical Cancer; Stage IIA Colon Cancer; Stage IIA Gastric Cancer; Stage IIA Ovarian Epithelial Cancer; Stage IIA Ovarian Germ Cell Tumor; Stage IIA Pancreatic Cancer; Stage IIA Rectal Cancer; Stage IIA Uterine Sarcoma; Stage IIB Cervical Cancer; Stage IIB Colon Cancer; Stage IIB Gastric Cancer; Stage IIB Ovarian Epithelial Cancer; Stage IIB Ovarian Germ Cell Tumor; Stage IIB Pancreatic Cancer; Stage IIB Rectal Cancer; Stage IIB Uterine Sarcoma; Stage IIC Colon Cancer; Stage IIC Ovarian Epithelial Cancer; Stage IIC Ovarian Germ Cell Tumor; Stage IIC Rectal Cancer; Stage III Bladder Cancer; Stage III Pancreatic Cancer; Stage III Renal Cell Cancer; Stage III Urethral Cancer; Stage IIIA Cervical Cancer; Stage IIIA Colon Cancer; Stage IIIA Gastric Cancer; Stage IIIA Ovarian Epithelial Cancer; Stage IIIA Ovarian Germ Cell Tumor; Stage IIIA Rectal Cancer; Stage IIIA Uterine Sarcoma; Stage IIIB Cervical Cancer; Stage IIIB Colon Cancer; Stage IIIB Gastric Cancer; Stage IIIB Ovarian Epithelial Cancer; Stage IIIB Ovarian Germ Cell Tumor; Stage IIIB Rectal Cancer; Stage IIIB Uterine Sarcoma; Stage IIIC Colon Cancer; Stage IIIC Gastric Cancer; Stage IIIC Ovarian Epithelial Cancer; Stage IIIC Ovarian Germ Cell Tumor; Stage IIIC Rectal Cancer; Stage IIIC

  6. Hodgkin's disease: correlation of clinical characteristics with probabilities for negative lymphangiogram vs. negative laparotomy findings in patients with stage I supradiaphragmatic presentations vs. those in patients with stage II

    International Nuclear Information System (INIS)

    Fuller, Lillian M.; Mirza, Nadeem Q.; Palmer, J. Lynn; Davis, Barry R.; Ha, Chul S.; Rodriguez, M. Alma; Hagemeister, Fredrick B.; Cabanillas, Fernando; McLaughlin, Peter; Butler, James J.; North, Luceil B.; Martin, Richard G.

    1998-01-01

    Purpose: At a time both when late complications and second malignancies have become a growing concern and when staging laparotomy has been largely abandoned and comparative studies for staging Hodgkin's disease by state of the art computed tomography (CT) vs. lymphangiography have revealed minimal differences in results for these procedures, our purpose for undertaking this study was twofold. Our initial reason was to determine and compare probabilities for negative abdominal findings for patients with Stage I presentations with those for patients with Stage II as determined by lymphangiography and subsequently by laparotomy for those patients who had negative lymphangiograms. Our second reason, being an extension of the first, was to create a resource that can be used in conjunction with other information for arriving at appropriate treatment decisions including giving either more or particularly less than standard institutional therapy and especially with respect to the abdomen. Methods and Materials: Data on 714 patients with prelymphangiogram Stage I-II upper torso presentations of Hodgkin's disease were entered prospectively in our database between 1968 and 1987. Twenty-eight with lymphocyte predominant disease, who had both negative lymphangiogram and negative laparotomy findings and 17 with questionable diagnoses of lymphocyte-depleted or unclassified disease were excluded from subsequent analyses of 669 patients with nodular sclerosis (NS) and mixed cellularity (MC) diagnoses. Results: Stage I: in final logistic models, negative lymphangiogram findings were associated strongly with a combination of no constitutional symptoms and nodular sclerosis histology, whereas negative laparotomy findings correlated strongly with a combination of no constitutional symptoms and female sex. Predicted probabilities depended on the ratios of favorable to unfavorable characteristics. Stage II: in final logistic models, negative lymphangiogram findings were associated

  7. Mantle Earthquakes in Thinned Proterozoic Lithosphere: Harrat Lunayyir, Saudi Arabia

    Science.gov (United States)

    Blanchette, A. R.; Klemperer, S. L.; Mooney, W. D.; Zahran, H. M.

    2017-12-01

    Harrat Lunayyir is an active volcanic field located in the western Arabian Shield 100 km outside of the Red Sea rift margin. We use common conversion point (CCP) stacking of P-wave receiver functions (PRFs) to show that the Moho is at 38 km depth, close to the 40 km crustal thickness measured in the center of the craton, whereas the lithosphere-asthenosphere boundary (LAB) is at 60 km, far shallower than the 150 km furthest in the craton. We locate 67 high-frequency earthquakes with mL ≤ 2.5 at depths of 40-50 km below the surface, located clearly within the mantle lid. The occurrence of earthquakes within the lithospheric mantle requires a geothermal temperature profile that is below equilibrium. The lithosphere cannot have thinned to its present thickness earlier than 15 Ma, either during an extended period of rifting possibly beginning 24 Ma or, more likely, as part of the second stage of rifting following collision between Arabia and Eurasia.

  8. Overexpression of the S100A2 protein as a prognostic marker for patients with stage II and III colorectal cancer

    Science.gov (United States)

    MASUDA, TAIKI; ISHIKAWA, TOSHIAKI; MOGUSHI, KAORU; OKAZAKI, SATOSHI; ISHIGURO, MEGUMI; IIDA, SATORU; MIZUSHIMA, HIROSHI; TANAKA, HIROSHI; UETAKE, HIROYUKI; SUGIHARA, KENICHI

    2016-01-01

    We aimed to identify a novel prognostic biomarker related to recurrence in stage II and III colorectal cancer (CRC) patients. Stage II and III CRC tissue mRNA expression was profiled using an Affymetrix Gene Chip, and copy number profiles of 125 patients were generated using an Affymetrix 250K Sty array. Genes showing both upregulated expression and copy number gains in cases involving recurrence were extracted as candidate biomarkers. The protein expression of the candidate gene was assessed using immunohistochemical staining of tissue from 161 patients. The relationship between protein expression and clinicopathological features was also examined. We identified 9 candidate genes related to recurrence of stage II and III CRC, whose mRNA expression was significantly higher in CRC than in normal tissue. Of these proteins, the S100 calcium-binding protein A2 (S100A2) has been observed in several human cancers. S100A2 protein overexpression in CRC cells was associated with significantly worse overall survival and relapse-free survival, indicating that S100A2 is an independent risk factor for stage II and III CRC recurrence. S100A2 overexpression in cancer cells could be a biomarker of poor prognosis in stage II and III CRC recurrence and a target for treatment of this disease. PMID:26783118

  9. Unexpected HIMU-type late-stage volcanism on the Walvis Ridge

    Science.gov (United States)

    Homrighausen, S.; Hoernle, K.; Geldmacher, J.; Wartho, J.-A.; Hauff, F.; Portnyagin, M.; Werner, R.; van den Bogaard, P.; Garbe-Schönberg, D.

    2018-06-01

    Volcanic activity at many oceanic volcanoes, ridges and plateaus often reawakens after hiatuses of up to several million years. Compared to the earlier magmatic phases, this late-stage (rejuvenated/post-erosional) volcanism is commonly characterized by a distinct geochemical composition. Late-stage volcanism raises two hitherto unanswered questions: Why does volcanism restart after an extended hiatus and what is the origin of this volcanism? Here we present the first 40Ar/39Ar age and comprehensive trace element and Sr-Nd-Pb-Hf isotopic data from seamounts located on and adjacent to the Walvis Ridge in the South Atlantic ocean basin. The Walvis Ridge is the oldest submarine part of the Tristan-Gough hotspot track and is famous as the original type locality for the enriched mantle one (EM I) end member. Consistent with the bathymetric data, the age data indicates that most of these seamounts are 20-40 Myr younger than the underlying or nearby Walvis Ridge basement. The trace element and isotope data reveal a distinct compositional range from the EM I-type basement. The composition of the seamounts extend from the St. Helena HIMU (high time-integrated 238U/204Pb mantle with radiogenic Pb isotope ratios) end member to an enriched (E) Mid-Ocean-Ridge Basalt (MORB) type composition, reflecting a two-component mixing trend on all isotope diagrams. The EMORB end member could have been generated through mixing of Walvis Ridge EM I with normal (N) MORB source mantle, reflecting interaction of Tristan-Gough (EM I-type) plume melts with the upper mantle. The long volcanic quiescence and the HIMU-like geochemical signature of the seamounts are unusual for classical hotspot related late-stage volcanism, indicating that these seamounts are not related to the Tristan-Gough hotspot volcanism. Two volcanic arrays in southwestern Africa (Gibeon-Dicker Willem and Western Cape province) display similar ages to the late-stage Walvis seamounts and also have HIMU-like compositions

  10. Coupled petrological-geodynamical modeling of a compositionally heterogeneous mantle plume

    Science.gov (United States)

    Rummel, Lisa; Kaus, Boris J. P.; White, Richard W.; Mertz, Dieter F.; Yang, Jianfeng; Baumann, Tobias S.

    2018-01-01

    Self-consistent geodynamic modeling that includes melting is challenging as the chemistry of the source rocks continuously changes as a result of melt extraction. Here, we describe a new method to study the interaction between physical and chemical processes in an uprising heterogeneous mantle plume by combining a geodynamic code with a thermodynamic modeling approach for magma generation and evolution. We pre-computed hundreds of phase diagrams, each of them for a different chemical system. After melt is extracted, the phase diagram with the closest bulk rock chemistry to the depleted source rock is updated locally. The petrological evolution of rocks is tracked via evolving chemical compositions of source rocks and extracted melts using twelve oxide compositional parameters. As a result, a wide variety of newly generated magmatic rocks can in principle be produced from mantle rocks with different degrees of depletion. The results show that a variable geothermal gradient, the amount of extracted melt and plume excess temperature affect the magma production and chemistry by influencing decompression melting and the depletion of rocks. Decompression melting is facilitated by a shallower lithosphere-asthenosphere boundary and an increase in the amount of extracted magma is induced by a lower critical melt fraction for melt extraction and/or higher plume temperatures. Increasing critical melt fractions activates the extraction of melts triggered by decompression at a later stage and slows down the depletion process from the metasomatized mantle. Melt compositional trends are used to determine melting related processes by focusing on K2O/Na2O ratio as indicator for the rock type that has been molten. Thus, a step-like-profile in K2O/Na2O might be explained by a transition between melting metasomatized and pyrolitic mantle components reproducible through numerical modeling of a heterogeneous asthenospheric mantle source. A potential application of the developed method

  11. Traveltime dispersion in an isotropic elastic mantle: strong lower-mantle signal in differential-frequency residuals

    Science.gov (United States)

    Schuberth, Bernhard S. A.; Zaroli, Christophe; Nolet, Guust

    2015-12-01

    We study wavefield effects of direct P- and S-waves in elastic and isotropic 3-D seismic structures derived from the temperature field of a high-resolution mantle circulation model. More specifically, we quantify the dispersion of traveltime residuals caused by diffraction in structures with dynamically constrained length scales and magnitudes of the lateral variations in seismic velocities and density. 3-D global wave propagation is simulated using a spectral element method. Intrinsic attenuation (i.e. dissipation of seismic energy) is deliberately neglected, so that any variation of traveltimes with frequency can be attributed to structural effects. Traveltime residuals are measured at 15, 22.5, 34 and 51 s dominant periods by cross-correlation of 3-D and 1-D synthetic waveforms. Additional simulations are performed for a model in which 3-D structure is removed in the upper 800 km to isolate the dispersion signal of the lower mantle. We find that the structural length scales inherent to a vigorously convecting mantle give rise to significant diffraction-induced body-wave traveltime dispersion. For both P- and S-waves, the difference between long-period and short-period residuals for a given source-receiver pair can reach up to several seconds for the period bands considered here. In general, these `differential-frequency' residuals tend to increase in magnitude with increasing short-period delay. Furthermore, the long-period signal typically is smaller in magnitude than the short-period one; that is, wave-front healing is efficient independent of the sign of the residuals. Unlike the single-frequency residuals, the differential-frequency residuals are surprisingly similar between the `lower-mantle' and the `whole-mantle' model for corresponding source-receiver pairs. The similarity is more pronounced in case of S-waves and varies between different combinations of period bands. The traveltime delay acquired in the upper mantle seems to cancel in these differential

  12. Mantle flow influence on subduction evolution

    Science.gov (United States)

    Chertova, Maria V.; Spakman, Wim; Steinberger, Bernhard

    2018-05-01

    The impact of remotely forced mantle flow on regional subduction evolution is largely unexplored. Here we investigate this by means of 3D thermo-mechanical numerical modeling using a regional modeling domain. We start with simplified models consisting of a 600 km (or 1400 km) wide subducting plate surrounded by other plates. Mantle inflow of ∼3 cm/yr is prescribed during 25 Myr of slab evolution on a subset of the domain boundaries while the other side boundaries are open. Our experiments show that the influence of imposed mantle flow on subduction evolution is the least for trench-perpendicular mantle inflow from either the back or front of the slab leading to 10-50 km changes in slab morphology and trench position while no strong slab dip changes were observed, as compared to a reference model with no imposed mantle inflow. In experiments with trench-oblique mantle inflow we notice larger effects of slab bending and slab translation of the order of 100-200 km. Lastly, we investigate how subduction in the western Mediterranean region is influenced by remotely excited mantle flow that is computed by back-advection of a temperature and density model scaled from a global seismic tomography model. After 35 Myr of subduction evolution we find 10-50 km changes in slab position and slab morphology and a slight change in overall slab tilt. Our study shows that remotely forced mantle flow leads to secondary effects on slab evolution as compared to slab buoyancy and plate motion. Still these secondary effects occur on scales, 10-50 km, typical for the large-scale deformation of the overlying crust and thus may still be of large importance for understanding geological evolution.

  13. Estimating the adjuvant chemotherapy effect in elderly stage II and III colon cancer patients in an observational study.

    Science.gov (United States)

    Kim, Ki-Yeol; Cha, In-Ho; Ahn, Joong Bae; Kim, Nam Kyu; Rha, Sun Young; Chung, Hyun Cheol; Roh, Jae Kyung; Shin, Sang Joon

    2013-05-01

    Adjuvant chemotherapy has been known as a standard treatment for patients with resected colon cancer. However, in elderly colon cancer patients, the characteristics of patients are heterogeneous with regard to life expectancy and comorbidities. Thus, with regard to the effectiveness of adjuvant chemotherapy for colon cancer, it is difficult to extrapolate data of clinical trials from the younger into the older general population. Data for 382 elderly colon cancer patients were analyzed: 217 in Stage II and 165 in Stage III. The efficacy of adjuvant chemotherapy was evaluated in elderly colon cancer patients after a match by the propensity score method. For matched patients with Stage II colon cancer, there was no significant efficacy of adjuvant chemotherapy in the risk of death during all follow-up periods (P-value, 0.06-0.37). Though there was a tendency that the adjuvant chemotherapy reduces the death rate during the follow-up periods, it was not statistically significant. In the case of Stage III, the adjuvant chemotherapy was significantly effective in matched patients for 5-year (hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.30-0.90) and overall survival (HR, 0.56; 95% CI, 0.34-0.94). Adjuvant chemotherapy for elderly patients with Stage II colon cancer is not effective, whereas elderly patients with Stage III with adjuvant chemotherapy appear to have a better survival rate in the general population. Copyright © 2012 Wiley Periodicals, Inc.

  14. Early positron emission tomography response-adapted treatment in stage I and II hodgkin lymphoma

    DEFF Research Database (Denmark)

    André, Marc P.E.; Girinsky, Théodore; Federico, Massimo

    2017-01-01

    Purpose Patients who receive combined modality treatment for stage I and II Hodgkin lymphoma (HL) have an excellent outcome. Early response evaluation with positron emission tomography (PET) scan may improve selection of patients who need reduced or more intensive treatments. Methods We performed...

  15. Large Topographic Rises on Venus: Implications for Mantle Upwelling

    Science.gov (United States)

    Stofan, Ellen R.; Smrekar, Suzanne E.; Bindschandler, Duane L.; Senske, David A.

    1995-01-01

    Topographic rises on Venus have been identified that are interpreted to be the surface manifestation of mantle upwellings. These features are classified into groups based on their dominant morphology. Atla and Beta Regiones are classified as rift-dominated, Dione, western Eistla, Bell, and Imdr Regiones as volcano-dominated, and Themis, eastern Eistla, and central Eistla Regiones as corona-dominated. At several topographic rises, geologic indicators were identified that may provide evidence of uplifted topography (e.g., volcanic flow features trending upslope). We assessed the minimum contribution of volcanic construction to the topography of each rise, which in general represents less than 5% of the volume of the rise, similar to the volumes of edifices at terrestrial hotspot swells. The total melt volume at each rise is approximated to be 10(exp 4) - 10(exp 6) cu km. The variations in morphology, topography, and gravity signatures at topographic rises are not interpreted to indicate variations in stage of evolution of a mantle upwelling. Instead, the morphologic variations between the three classes of topographic rises are interpreted to indicate the varying influences of lithospheric structure, plume characteristics, and regional tectonic environment. Within each class, variations in topography, gravity, and amount of volcanism may be indicative of differing stages of evolution. The similarity between swell and volcanic volumes for terrestrial and Venusian hotspots implies comparable time-integrated plume strengths for individual upwellings on the two planets.

  16. Stagnant lids and mantle overturns: Implications for Archaean tectonics, magmagenesis, crustal growth, mantle evolution, and the start of plate tectonics

    Directory of Open Access Journals (Sweden)

    Jean H. Bédard

    2018-01-01

    Full Text Available The lower plate is the dominant agent in modern convergent margins characterized by active subduction, as negatively buoyant oceanic lithosphere sinks into the asthenosphere under its own weight. This is a strong plate-driving force because the slab-pull force is transmitted through the stiff sub-oceanic lithospheric mantle. As geological and geochemical data seem inconsistent with the existence of modern-style ridges and arcs in the Archaean, a periodically-destabilized stagnant-lid crust system is proposed instead. Stagnant-lid intervals may correspond to periods of layered mantle convection where efficient cooling was restricted to the upper mantle, perturbing Earth's heat generation/loss balance, eventually triggering mantle overturns. Archaean basalts were derived from fertile mantle in overturn upwelling zones (OUZOs, which were larger and longer-lived than post-Archaean plumes. Early cratons/continents probably formed above OUZOs as large volumes of basalt and komatiite were delivered for protracted periods, allowing basal crustal cannibalism, garnetiferous crustal restite delamination, and coupled development of continental crust and sub-continental lithospheric mantle. Periodic mixing and rehomogenization during overturns retarded development of isotopically depleted MORB (mid-ocean ridge basalt mantle. Only after the start of true subduction did sequestration of subducted slabs at the core-mantle boundary lead to the development of the depleted MORB mantle source. During Archaean mantle overturns, pre-existing continents located above OUZOs would be strongly reworked; whereas OUZO-distal continents would drift in response to mantle currents. The leading edge of drifting Archaean continents would be convergent margins characterized by terrane accretion, imbrication, subcretion and anatexis of unsubductable oceanic lithosphere. As Earth cooled and the background oceanic lithosphere became denser and stiffer, there would be an increasing

  17. Petrology and geochemistry of the high-Cr podiform chromitites of the Köycegiz ophiolite, southwest Turkey: implications for the multi-stage evolution of the oceanic upper mantle

    Science.gov (United States)

    Xiong, Fahui; Yang, Jingsui; Dilek, Yildirim; Wang, ChunLian; Hao, Xiaolin; Xu, Xiangzhen; Lian, Dongyang

    2018-03-01

    Ophiolites exposed across the western Tauride belt in Turkey represent tectonically emplaced fragments of oceanic lithosphere obducted onto the continental margin following the closure of the Neotethys Ocean during the Late Cretaceous. The ultramafic massif of Köycegiz, which is located in the ophiolitic belt of southwestern Turkey, is a major source of metallurgical chromitite ore. The massif comprises a base of tectonized harzburgite with minor dunite overlain by a magmatic sequence of wehrlite, pyroxenite, troctolite and gabbro. Only sparse refractory chromitites occur within the harzburgites; in contrast, the upper and middle sections of the peridotite sequence contain abundant metallurgical chromitites. The peridotites record abundant evidence of mantle metasomatism on various scales, as the Fo values of olivine in harzburgite are 90.1-95.4, whereas those in dunite are 90.1-91.8. The compositions of the melts passing through the peridotites changed gradually from arc tholeiite to boninite due to melt-rock reactions, thus producing more Cr-rich chromitites in the upper part of the body. Most of the chromitites have high Cr numbers (77-78), although systematic changes in the compositions of the olivine and chromian spinel occur from the harzburgites to the dunite envelopes to the chromitites, reflecting melt-rock reactions. The calculated ΔlogfO2 (FMQ) values range from - 2.77 to + 1.03 in the chromitites, - 2.73 to -0.01 in the harzburgites, and - 1.65 to + 0.45 in the dunites. All of the available evidence suggests that the Köycegiz ophiolite formed in a supra-subduction zone (SSZ) mantle wedge. These models indicate that the harzburgites represent the products of first-stage melting and low degrees of melt-rock interaction that occurred in a mid-ocean ridge (MOR) environment. In contrast, the chromitites and dunites represent the products of second-stage melting and related refertilization, which occurred in an SSZ environment.

  18. Mantle strength of the San Andreas fault system and the role of mantle-crust feedbacks

    NARCIS (Netherlands)

    Chatzaras, V.; Tikoff, B.; Newman, J.; Withers, A.C.; Drury, M.R.

    2015-01-01

    In lithospheric-scale strike-slip fault zones, upper crustal strength is well constrained from borehole observations and fault rock deformation experiments, but mantle strength is less well known. Using peridotite xenoliths, we show that the upper mantle below the San Andreas fault system

  19. The mantle-plume model, its feasibility and consequences

    NARCIS (Netherlands)

    Calsteren, van P.W.C.

    1981-01-01

    High beat-flow foci on the Earth have been named ‘hot-spots’ and are commonly correlated with ‘mantle-plumes’ in the deep. A mantle plume may be described as a portion of mantle material with a higher heat content than its surroundings. The intrusion of a mantle-plume is inferred to be similar to

  20. Hawaiian lavas: a window into mantle dynamics

    Science.gov (United States)

    Jones, Tim; Davies, Rhodri; Campbell, Ian

    2017-04-01

    The emergence of double track volcanism at Hawaii has traditionally posed two problems: (i) the physical emergence of two parallel chains of volcanoes at around 3 Ma, named the Loa and Kea tracks after the largest volcanoes in their sequence, and (ii) the systematic geochemical differences between the erupted lavas along each track. In this study, we dissolve this distinction by providing a geodynamical explanation for the physical emergence of double track volcanism at 3 Ma and use numerical models of the Hawaiian plume to illustrate how this process naturally leads to each volcanic track sampling distinct mantle compositions, which accounts for much of the geochemical characteristics of the Loa and Kea trends.

  1. Mantle geofluid and uranium ore-formation model

    International Nuclear Information System (INIS)

    Wu Jianhua; Liu Shuai; Yu Dagan; Zhang Bangtong

    2005-01-01

    Results of the recent research show that volcanic-type and granite-type uranium deposits have both early and late phases of uranium mineralization, and the early phase uranium mineralization is characterized by metallogenetic features of mantle fluids. This paper discusses the geofluids and related metallogenesis, as well as characteristics of early phase uranium mineralisation, and emphasizes, that the ΣCO 2 , U and H 2 O, that comprise the bulk of the ore-forming hot fluids, are originated from different sources, namely CO 2 comes from mantle fluids, U comes from country rocks the mantle fluids have passed during their ascending way, and H 2 O comes from mantle fluids and country rocks the mantle fluids have passed during their ascending way. (authors)

  2. Seismic Structure of the Shallow Mantle Beneath the Endeavor Segment of the Juan de Fuca Ridge

    Science.gov (United States)

    VanderBeek, B. P.; Toomey, D. R.; Hooft, E. E.; Wilcock, W. S.; Weekly, R. T.; Soule, D. C.

    2013-12-01

    We present tomographic images of the seismic structure of the shallow mantle beneath the intermediate-spreading Endeavor segment of the Juan de Fuca ridge. Our results provide insight into the relationship between magma supply from the mantle and overlying ridge crest processes. We use seismic energy refracted below the Moho (Pn), as recorded by the Endeavor tomography (ETOMO) experiment, to image the anisotropic and isotropic P wave velocity structure. The ETOMO experiment was an active source seismic study conducted in August 2009 as part of the RIDGE2000 science program. The experimental area extends 100 km along- and 60 km across-axis and encompasses active hydrothermal vent fields near the segment center, the eastern end of the Heck seamount chain, and two overlapping spreading centers (OSCs) at either end of the segment. Previous tomographic analyses of seismic arrivals refracted through the crust (Pg), and reflected off the Moho (PmP), constrain a three-dimensional starting model of crustal velocity and thickness. These Pg and PmP arrivals are incorporated in our inversion of Pn travel-time data to further constrain the isotropic and anisotropic mantle velocity structure. Preliminary results reveal three distinct mantle low-velocity zones, inferred as regions of mantle melt delivery to the base of the crust, that are located: (i) off-axis near the segment center, (ii) beneath the Endeavor-West Valley OSC, and (iii) beneath the Cobb OSC near Split Seamount. The mantle anomalies are located at intervals of ~30 to 40 km along-axis and the low velocity anomalies beneath the OSCs are comparable in magnitude to the one located near the segment center. The direction of shallow mantle flow is inferred from azimuthal variations in Pn travel-time residuals relative to a homogeneous isotropic mantle. Continuing analysis will focus on constraining spatial variations in the orientation of azimuthal anisotropy. On the basis of our results, we will discuss the transport of

  3. Thyroid dysfunction after mantle irradiation of Hodgkin`s disease patients

    Energy Technology Data Exchange (ETDEWEB)

    Khoo, V.S.; Liew, K.H.; Crennan, E.C.; D`Costa, I.M. [Peter MacCallum Caner Institute, East Melbourne, VIC (Australia). Department of Radiation Oncology; Quong, G. [Austin and Repatriation Medical Centre, West Heidelberg, VIC (Australia). Department of Radiation Oncology

    1998-02-01

    Thyroid dysfunction can develop in patients with Hodgkin`s disease who are treated with mantle irradiation. During the period 1970-89, the records of 320 patients who received mantle irradiation and who had thyroid function tests (TFT) were retrospectively reviewed. The median age was 30 years (range, 7-69 years). The median mantle and thyroid dose was 36 Gy (range, 30-40 Gy) and 39.8 Gy (range, 32-65 Gy), respectively. Overall thyroid dysfunction was present in 39% of the patients. Clinical hypothyroidism was seen in 10% and biochemical hypothyroidism was noted in 25%. Hyperthyroidism was found in 4% of patients. Thyroid nodules had developed in six patients (2%), of which those in four patients were malignant. Age, sex, histological subtype, stage of disease, dose, Iymphangiogram and treatment with chemotherapy were not significant factors in the development of thyroid dysfunction. The narrow dose range prevented adequate analysis of dose effect. The results indicate that the incidence of thyroid abnormalities is high enough to warrant regular TFT assessment with pre-irradiation levels and follow-up testing for life because the development of abnormalities can occur many years later. Thyroid examination should form part of the routine follow-up examination and any abnormality should be promptly investigated. Copyright (1998) Blackwell Science Pty Ltd 32 refs., 3 tabs.

  4. Sub-Moho Reflectors, Mantle Faults and Lithospheric Rheology

    Science.gov (United States)

    Brown, L. D.

    2013-12-01

    One of the most unexpected and dramatic observations from the early years of deep reflection profiling of the continents using multichannel CMP techniques was the existing of prominent reflections from the upper mantle. The first of these, the Flannan thrust/fault/feature, was traced by marine profiling of the continental margin offshore Britain by the BIRPS program, which soon found them to be but one of several clear sub-crustal discontinuities in that area. Subsequently, similar mantle reflectors have been observed in many areas around the world, most commonly beneath Precambrian cratonic areas. Many, but not all, of these mantle reflections appear to arise from near the overlying Moho or within the lower crust before dipping well into the mantle. Others occur as subhorizontal events at various depths with the mantle, with one suite seeming to cluster at a depth of about 75 km. The dipping events have been variously interpreted as mantle roots of crustal normal faults or the deep extension of crustal thrust faults. The most common interpretation, however, is that these dipping events are the relicts of ancient subduction zones, the stumps of now detached Benioff zones long since reclaimed by the deeper mantle. In addition to the BIRPS reflectors, the best known examples include those beneath Fennoscandia in northern Europe, the Abitibi-Grenville of eastern Canada, and the Slave Province of northwestern Canada (e.g. on the SNORCLE profile). The most recently reported example is from beneath the Sichuan Basin of central China. The preservation of these coherent, and relatively delicate appearing, features beneath older continental crust and presumably within equally old (of not older) mantle lithosphere, has profound implications for the history and rheology of the lithosphere in these areas. If they represent, as widely believe, some form of faulting with the lithosphere, they provide corollary constraints on the nature of faulting in both the lower crust and

  5. Analyzing proteasomal subunit expression reveals Rpt4 as a prognostic marker in stage II colorectal cancer.

    LENUS (Irish Health Repository)

    2012-02-01

    Colorectal cancer is a leading cause of cancer-related deaths worldwide. Early diagnosis and treatment of colorectal cancer is the key to improving survival rates and as such a need exists to identify patients who may benefit from adjuvant chemotherapy. The dysregulation of the ubiquitin-proteasome system (UPS) has been implicated in oncogenesis and cancer cell survival, and proteasome inhibitors are in clinical use for a number of malignancies including multiple myeloma. In our study, we examined the protein expression of several key components of the UPS in colorectal cancer using immunohistochemistry to determine expression levels of ubiquitinylated proteins and the proteasomal subunits, 20S core and Rpt4 in a cohort of 228 patients with colon cancer. Multivariate Cox analysis revealed that neither the intensity of either ubiquitinylated proteins or the 20S core was predictive in either Stage II or III colon cancer for disease free survival or overall survival. In contrast, in Stage II patients increased Rpt4 staining was significantly associated with disease free survival (Cox proportional hazard ratio 0.605; p = 0.0217). Our data suggest that Rpt4 is an independent prognostic variable for Stage II colorectal cancer and may aid in the decision of which patients undergo adjuvant chemotherapy.

  6. Correlation between hindfoot joint three-dimensional kinematics and the changes of the medial arch angle in stage II posterior tibial tendon dysfunction flatfoot.

    Science.gov (United States)

    Zhang, Yi-Jun; Xu, Jian; Wang, Yue; Lin, Xiang-Jin; Ma, Xin

    2015-02-01

    The aim of this study was to explore the correlation between the kinematics of the hindfoot joint and the medial arch angle change in stage II posterior tibial tendon dysfunction flatfoot three-dimensionally under loading. Computed tomography (CT) scans of 12 healthy feet and 12 feet with stage II posterior tibial tendon dysfunction flatfoot were taken both in non- and full-body-weight-bearing condition. The CT images of the hindfoot bones were reconstructed into three-dimensional models with Mimics and Geomagic reverse engineering software. The three-dimensional changes of the hindfoot joint were calculated to determine their correlation to the medial longitudinal arch angle. The medial arch angle change was larger in stage II posterior tibial tendon dysfunction flatfoot compared to that in healthy foot under loading. The rotation and translation of the talocalcaneal joint, the talonavicular joint and the calcanocuboid joint had little influence on the change of the medial arch angle in healthy foot. However, the eversion of the talocalcaneal joint, the proximal translation of the calcaneus relative to the talus and the dorsiflexion of talonavicular joint could increase the medial arch angle in stage II posterior tibial tendon dysfunction flatfoot under loading. Joint instability occurred in patients with stage II posterior tibial tendon dysfunction flatfoot under loading. Limitation of over movement of the talocalcaneal joint and the talonavicular joint may help correct the medial longitudinal arch in stage II posterior tibial tendon dysfunction flatfoot. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Thermoconvective waves in the earth's mantle

    Science.gov (United States)

    Birger, B. I.

    1980-06-01

    The thermoconvective instability of the Earth's mantle is analysed. The mantle is modelled as an infinite horizontal layer with a free upper surface, heated from below. The creep in the mantle is supposed to be transient when strains are small. This transient creep is described by Lomnitz's law modified by Jeffreys (1958a). It is shown that disturbances, in the form of thermoconvective waves with a period of 10 8 - 10 9y and wavelength of the order 10 3 km, can propagate through the mantle without attenuation. These waves induce oscillations of the Earth's surface. The pattern of flows differs greatly from that suggested by plate tectonics. An attempt is made to give a new explanation for the linear magnetic anomalies over oceanic ridges.

  8. Does cement mantle thickness really matter?

    OpenAIRE

    Caruana, J.

    2008-01-01

    The thickness of the cement mantle around the femoral component of total hip replacements is a contributing factor to aseptic loosening and revision. Nevertheless, various designs of stems and surgical tooling lead to cement mantles of differing thicknesses. This thesis is concerned with variability in cement thickness around the Stanmore Hip, due to surgical approach, broach size and stem orientation, and its effects on stress and cracking in the cement. The extent to which cement mantle thi...

  9. Does adjuvant systemic therapy with interferon-alpha for stage II-III melanoma prolong survival?

    NARCIS (Netherlands)

    Eggermont, Alexander M. M.; Punt, Cornelis J. A.

    2003-01-01

    The experience with interferon-alpha in malignant melanoma resembles, to some degree, the experience with various kinds of adjuvant immunotherapeutic agents where 25 years of phase III trials of adjuvant therapy in stage II-IIII melanoma have not defined a standard therapy. Most trials failed to

  10. Formation and modification of chromitites in the mantle

    Science.gov (United States)

    Arai, Shoji; Miura, Makoto

    2016-11-01

    Podiform chromitites have long supplied us with unrivaled information on various mantle processes, including the peridotite-magma reaction, deep-seated magmatic evolution, and mantle dynamics. The recent discovery of ultrahigh-pressure (UHP) chromitites not only sheds light on a different aspect of podiform chromitites, but also changes our understanding of the whole picture of podiform chromitite genesis. In addition, new evidence was recently presented for hydrothermal modification/formation chromite/chromitite in the mantle, which is a classical but innovative issue. In this context, we present here an urgently needed comprehensive review of podiform chromitites in the upper mantle. Wall-rock control on podiform chromitite genesis demonstrates that the peridotite-magma reaction at the upper mantle condition is an indispensable process. We may need a large system in the mantle, far larger than the size of outcrops or mining areas, to fulfill the Cr budget requirement for podiform chromitite genesis. The peridotite-magma reaction over a large area may form a melt enriched with Na and other incompatible elements, which mixes with a less evolved magma supplied from the depth to create chromite-oversaturated magma. The incompatible-element-rich magma trapped by the chromite mainly precipitates pargasite and aspidolite (Na analogue of phlogopite), which are stable under upper mantle conditions. Moderately depleted harzburgites, which contain chromite with a moderate Cr# (0.4-0.6) and a small amount of clinopyroxene, are the best reactants for the chromitite-forming reaction, and are the best hosts for podiform chromitites. Arc-type chromitites are dominant in ophiolites, but some are of the mid-ocean ridge type; chromitites may be common beneath the ocean floor, although it has not yet been explored for chromitite. The low-pressure (upper mantle) igneous chromitites were conveyed through mantle convection or subduction down to the mantle transition zone to form

  11. Carbonate stability in the reduced lower mantle

    Science.gov (United States)

    Dorfman, Susannah M.; Badro, James; Nabiei, Farhang; Prakapenka, Vitali B.; Cantoni, Marco; Gillet, Philippe

    2018-05-01

    Carbonate minerals are important hosts of carbon in the crust and mantle with a key role in the transport and storage of carbon in Earth's deep interior over the history of the planet. Whether subducted carbonates efficiently melt and break down due to interactions with reduced phases or are preserved to great depths and ultimately reach the core-mantle boundary remains controversial. In this study, experiments in the laser-heated diamond anvil cell (LHDAC) on layered samples of dolomite (Mg, Ca)CO3 and iron at pressure and temperature conditions reaching those of the deep lower mantle show that carbon-iron redox interactions destabilize the MgCO3 component, producing a mixture of diamond, Fe7C3, and (Mg, Fe)O. However, CaCO3 is preserved, supporting its relative stability in carbonate-rich lithologies under reducing lower mantle conditions. These results constrain the thermodynamic stability of redox-driven breakdown of carbonates and demonstrate progress towards multiphase mantle petrology in the LHDAC at conditions of the lowermost mantle.

  12. Adjuvant chemotherapy for stage II colon cancer: influence of care structures' characteristics on a controversial clinical practice.

    Science.gov (United States)

    Alter, Eléonore; Phelip, Jean-Marc; Guilhot, Jean-Noel; Matysiak, Michel; Vermorel, Michel; Roblin, Xavier

    2007-11-01

    Adjuvant chemotherapy for stage II colon cancer is a controversial practice and is not recommended by the French Consensus Conference outside of therapeutic trial. To assess, within a well-defined population, the influence of hospital characteristics in this practice. In the Rhône-Alpes region (10% of the French population), 534 patients presenting with colon cancer stage II were operated on in 81 hospitals in the year 2000. The influence of hospital characteristics on the use of adjuvant chemotherapy was assessed using a multivariate logistic regression. Overall, 19.5% of patients received adjuvant chemotherapy. Younger age, T4 tumour, hospital volume lower than 20 colon cancer surgeries [odds ratio (OR) 2.96; Pclinical complications at diagnosis were independently associated with higher rates of chemotherapy. On the other hand, a number of examined lymph nodes lower than recommendations did not have any influence on chemotherapy use. Hospital characteristics had independently influenced the practice of adjuvant chemotherapy in stage II colon cancer. The more important institutional factor was the hospital procedure volume. The decisions of the multidisciplinary committees appeared at times paradoxical; a more comprehensive evaluation of this practice is needed.

  13. Improvements in 5-year outcomes of stage II/III rectal cancer relative to colon cancer.

    Science.gov (United States)

    Renouf, Daniel J; Woods, Ryan; Speers, Caroline; Hay, John; Phang, P Terry; Fitzgerald, Catherine; Kennecke, Hagen

    2013-12-01

    Stage for stage, rectal cancer has historically been associated with inferior survival compared with colon cancer. Randomized trials of rectal cancer have generally demonstrated improvements in locoregional relapse but not survival. We compared therapy and outcomes of colon versus rectal cancer in 2 time cohorts to determine if relative improvements have occurred. Patients with resected stage II/III colorectal cancer referred to the British Columbia Cancer Agency in 1989/1990 and 2001/2002 were identified. The higher of clinical or pathologic stage was used for patients receiving preoperative chemoradiation. Disease-specific survival (DSS) and overall survival (OS) were compared for rectal and colon cancer between the 2 cohorts. Kaplan-Meier method was used for survival analysis. A total of 1427 patients were included, with 375 from 1989/1990 and 1052 from 2001/2002. Between 1989/1990 and 2001/2002 there were significant increases in the use of perioperative chemotherapy for both rectal and colon cancer (Prectal cancer. DSS significantly improved for rectal (Pcolon cancer (P=0.069). Five-year OS was significantly inferior for rectal versus colon cancer in 1989/1990 (46.1% vs. 57.2%, P=0.023) and was similar to that of colon cancer in 2001/2002 (63.7% vs. 66.2%, P=0.454). Advances in locoregional and systemic therapy significantly improved survival among patients with rectal cancer. DSS and OS are now similar between colon and rectal cancer for both stage II and III disease.

  14. Sublithospheric flows in the mantle

    Science.gov (United States)

    Trifonov, V. G.; Sokolov, S. Yu.

    2017-11-01

    The estimated rates of upper mantle sublithospheric flows in the Hawaii-Emperor Range and Ethiopia-Arabia-Caucasus systems are reported. In the Hawaii-Emperor Range system, calculation is based on motion of the asthenospheric flow and the plate moved by it over the branch of the Central Pacific plume. The travel rate has been determined based on the position of variably aged volcanoes (up to 76 Ma) with respect to the active Kilauea Volcano. As for the Ethiopia-Arabia-Caucasus system, the age of volcanic eruptions (55-2.8 Ma) has been used to estimate the asthenospheric flow from the Ethiopian-Afar superplume in the northern bearing lines. Both systems are characterized by variations in a rate of the upper mantle flows in different epochs from 4 to 12 cm/yr, about 8 cm/yr on average. Analysis of the global seismic tomographic data has made it possible to reveal rock volumes with higher seismic wave velocities under ancient cratons; rocks reach a depth of more than 2000 km and are interpreted as detached fragments of the thickened continental lithosphere. Such volumes on both sides of the Atlantic Ocean were submerged at an average velocity of 0.9-1.0 cm/yr along with its opening. The estimated rates of the mantle flows clarify the deformation properties of the mantle and regulate the numerical models of mantle convection.

  15. Survival Impact of Adjuvant Radiation Therapy in Masaoka Stage II to IV Thymomas: A Systematic Review and Meta-analysis

    International Nuclear Information System (INIS)

    Lim, Yu Jin; Kim, Eunji; Kim, Hak Jae; Wu, Hong-Gyun; Yan, Jinchun; Liu, Qin; Patel, Shilpen

    2016-01-01

    Purpose: To evaluate the survival impact of postoperative radiation therapy (PORT) in stage II to IV thymomas, using systematic review and meta-analysis. Methods and Materials: A database search was conducted with EMBASE, PubMed, Web of Science, Cochrane Library, and Ovid from inception to August 2015. Thymic carcinomas were excluded, and studies comparing overall survival (OS) with and without PORT in thymomas were included. The hazard ratios (HRs) of OS were extracted, and a random-effects model was used in the pooled analysis. Results: Seven retrospective series with a total of 1724 patients were included and analyzed. Almost all of the patients underwent macroscopically complete resection, and thymoma histology was confirmed by the World Health Organization criteria. In the overall analysis of stage II to IV thymomas, OS was not altered with the receipt of PORT (HR 0.79, 95% confidence interval [CI] 0.58-1.08). Although PORT was not associated with survival difference in Masaoka stage II disease (HR 1.45, 95% CI 0.83-2.55), improved OS was observed with the addition of PORT in the discrete pooled analysis of stage III to IV (HR 0.63, 95% CI 0.40-0.99). Significant heterogeneity and publication bias were not found in the analyses. Conclusions: From the present meta-analysis of sole primary thymomas, we suggest the potential OS benefit of PORT in locally advanced tumors with macroscopically complete resection, but not in stage II disease. Further investigations with sufficient survival data are needed to establish detailed treatment indications.

  16. Survival Impact of Adjuvant Radiation Therapy in Masaoka Stage II to IV Thymomas: A Systematic Review and Meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Yu Jin; Kim, Eunji [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Hak Jae, E-mail: khjae@snu.ac.kr [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Wu, Hong-Gyun [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of); Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul (Korea, Republic of); Yan, Jinchun [Department of Radiation Oncology, Dalian Medical University, Liaoning (China); Department of Radiation Oncology, Fudan University Cancer Hospital, Shanghai (China); Liu, Qin [The Wistar Institute, Philadelphia, Pennsylvania (United States); Patel, Shilpen [Department of Radiation Oncology, University of Washington Medical Center, Seattle, Washington (United States)

    2016-04-01

    Purpose: To evaluate the survival impact of postoperative radiation therapy (PORT) in stage II to IV thymomas, using systematic review and meta-analysis. Methods and Materials: A database search was conducted with EMBASE, PubMed, Web of Science, Cochrane Library, and Ovid from inception to August 2015. Thymic carcinomas were excluded, and studies comparing overall survival (OS) with and without PORT in thymomas were included. The hazard ratios (HRs) of OS were extracted, and a random-effects model was used in the pooled analysis. Results: Seven retrospective series with a total of 1724 patients were included and analyzed. Almost all of the patients underwent macroscopically complete resection, and thymoma histology was confirmed by the World Health Organization criteria. In the overall analysis of stage II to IV thymomas, OS was not altered with the receipt of PORT (HR 0.79, 95% confidence interval [CI] 0.58-1.08). Although PORT was not associated with survival difference in Masaoka stage II disease (HR 1.45, 95% CI 0.83-2.55), improved OS was observed with the addition of PORT in the discrete pooled analysis of stage III to IV (HR 0.63, 95% CI 0.40-0.99). Significant heterogeneity and publication bias were not found in the analyses. Conclusions: From the present meta-analysis of sole primary thymomas, we suggest the potential OS benefit of PORT in locally advanced tumors with macroscopically complete resection, but not in stage II disease. Further investigations with sufficient survival data are needed to establish detailed treatment indications.

  17. The Mantle and Basalt-Crust Interaction Below the Mount Taylor Volcanic Field, New Mexico

    Science.gov (United States)

    Schrader, Christian M.; Crumpler, Larry S.; Schmidt, Marick E.

    2010-01-01

    The Mount Taylor Volcanic Field (MTVF) lies on the Jemez Lineament on the southeastern margin of the Colorado Plateau. The field is centered on the Mt. Taylor composite volcano and includes Mesa Chivato to the NE and Grants Ridge to the WSW. MTVF magmatism spans approximately 3.8-1.5 Ma (K-Ar). Magmas are dominantly alkaline with mafic compositions ranging from basanite to hy-basalt and felsic compositions ranging from ne-trachyte to rhyolite. We are investigating the state of the mantle and the spatial and temporal variation in basalt-crustal interaction below the MTVF by examining mantle xenoliths and basalts in the context of new mapping and future Ar-Ar dating. The earliest dated magmatism in the field is a basanite flow south of Mt. Taylor. Mantle xenolith-bearing alkali basalts and basanites occur on Mesa Chivato and in the region of Mt. Taylor, though most basalts are peripheral to the main cone. Xenolith-bearing magmatism persists at least into the early stages of conebuilding. Preliminary examination of the mantle xenolith suite suggests it is dominantly lherzolitic but contains likely examples of both melt-depleted (harzburgitic) and melt-enriched (clinopyroxenitic) mantle. There are aphyric and crystal-poor hawaiites, some of which are hy-normative, on and near Mt. Taylor, but many of the more evolved MTVF basalts show evidence of complex histories. Mt. Taylor basalts higher in the cone-building sequence contain >40% zoned plagioclase pheno- and megacrysts. Other basalts peripheral to Mt. Taylor and at Grants Ridge contain clinopyroxene and plagioclase megacrysts and cumulate-textured xenoliths, suggesting they interacted with lower crustal cumulates. Among the questions we are addressing: What was the chemical and thermal state of the mantle recorded by the basaltic suites and xenoliths and how did it change with time? Are multiple parental basalts (Si-saturated vs. undersaturated) represented and, if so, what changes in the mantle or in the tectonic

  18. Characteristics of Vertical Mantle Heat Exchangers for Solar Water Heaters

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Morrison, G.L.; Behnia, M.

    1999-01-01

    - The flow structure in vertical mantle heat exchangers was investigated using a full-scale tank designed to facilitate flow visualisation. The flow structure and velocities in the mantle were measured using a particle Image Velocimetry (PIV) system. A CFD simulation model of vertical mantle heat...... exchangers was also developed for detailed evaluation of the heat flux distribution over the mantle surface. Both the experimental and simulation results indicate that distribution of the flow around the mantle gap is governed by buoyancy driven recirculation in the mantle. The operation of the mantle...

  19. MODELLING MANTLE TANKS FOR SDHW SYSTEMS USING PIV AND CFD

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Morrison, G.L.; Behnia, Masud

    1999-01-01

    Characteristics of vertical mantle heat exchanger tanks for SDHW systems have been investigated experimentally and theoretically using particle image velocimetry (PIV) and CFD modelling. A glass model of a mantle heat exchanger tank was constructed so that the flow distribution in the mantle could...... be studied using the PIV test facility. Two transient three-dimensional CFD-models of the glass model mantle tank were developed using the CFD-programmes CFX and FLUENT.The experimental results illustrate that the mantle flow structure in the mantle is complicated and the distribution of flow in the mantle...

  20. Conjunctival mass as an initial presentation of mantle cell lymphoma: a case report

    Directory of Open Access Journals (Sweden)

    Khanlari Mahsa

    2012-12-01

    Full Text Available Abstract Background To describe a rare manifestation of mantle cell lymphoma (MCL in conjunctiva, with clinical, hisologic, immunohistologic and genetic findings together with review of the Literature. Case presentation Most ocular adnexal lymphomas are extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT. A few cases of ocular adnexal mantle cell lymphomas have been reported in the literature. We present a case of mantle cell lymphoma presenting as right conjunctival mass of at least three months duration in a 64-year-old man. Histopathologic examination showed a proliferation of monomorphous small-to-medium-sized lymphoid cells with cleaved nuclei in the subconjunctiva. By immunohistochemistry, the infiltrate was positive for CD20, CD5, BCL-2, cyclin D1, and the transcription factor SOX11. Fluorescent in situ hybridization demonstrated the presence of IGH-CCND1 fusion indicating t(11;14. Conclusion A rigorous approach to initial diagnosis and staging of small cell lymphomas of the ocular adnexa is needed. The recognition of ocular MCL requires appropriate immunohistochemical staining and/or genetic confirmation to differentiate this rare form of presentation of MCL from other more frequent small cell lymphomas.

  1. The impact of involved node, involved field and mantle field radiotherapy on estimated radiation doses and risk of late effects for pediatric patients with Hodgkin lymphoma

    DEFF Research Database (Denmark)

    Maraldo, M V; Jørgensen, M; Brodin, N P

    2014-01-01

    BACKGROUND: The use of radiotherapy (RT) is debated for pediatric patients with Hodgkin lymphoma (HL) due to the late effects of treatment. Radiation doses to the thyroid, heart, lungs, and breasts are compared with the extensive mantle field (MF), Involved Field RT(IFRT), Modified IFRT (m......IFRT), and Involved Node RT (INRT) and the risk of radiation-induced cardiovascular disease, secondary cancers, and the corresponding Life Years Lost (LYL) is estimated with each technique. PROCEDURE: INRT, mIFRT, IFRT, and MF plans (20 and 30 Gy) were simulated for 10 supradiaphragmatic, clinical stage I......–II classical HL patients lung, breast, and thyroid cancer with each technique were estimated. The estimated excess risks attributable to RT were based on HL series with long-term follow...

  2. Fludarabine Phosphate, Melphalan, Total-Body Irradiation, Donor Stem Cell Transplant in Treating Patients With Hematologic Cancer or Bone Marrow Failure Disorders

    Science.gov (United States)

    2017-11-29

    Accelerated Phase Chronic Myelogenous Leukemia; Acute Myeloid Leukemia With Multilineage Dysplasia Following Myelodysplastic Syndrome; Adult Acute Lymphoblastic Leukemia in Remission; Adult Acute Myeloid Leukemia in Remission; Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities; Adult Acute Myeloid Leukemia With Del(5q); Adult Acute Myeloid Leukemia With Inv(16)(p13;q22); Adult Acute Myeloid Leukemia With t(15;17)(q22;q12); Adult Acute Myeloid Leukemia With t(16;16)(p13;q22); Adult Acute Myeloid Leukemia With t(8;21)(q22;q22); Adult Nasal Type Extranodal NK/T-cell Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Aplastic Anemia; Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative; Childhood Acute Lymphoblastic Leukemia in Remission; Childhood Acute Myeloid Leukemia in Remission; Childhood Chronic Myelogenous Leukemia; Childhood Diffuse Large Cell Lymphoma; Childhood Immunoblastic Large Cell Lymphoma; Childhood Myelodysplastic Syndromes; Childhood Nasal Type Extranodal NK/T-cell Lymphoma; Chronic Eosinophilic Leukemia; Chronic Myelomonocytic Leukemia; Chronic Neutrophilic Leukemia; Chronic Phase Chronic Myelogenous Leukemia; de Novo Myelodysplastic Syndromes; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Fanconi Anemia; Juvenile Myelomonocytic Leukemia; Myelodysplastic/Myeloproliferative Neoplasm, Unclassifiable; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Adult Burkitt Lymphoma; Noncontiguous Stage II Adult Diffuse Large Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Noncontiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Noncontiguous Stage II Adult Lymphoblastic Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Mantle Cell Lymphoma

  3. Iron-carbonate interaction at Earth's core-mantle boundary

    Science.gov (United States)

    Dorfman, S. M.; Badro, J.; Nabiei, F.; Prakapenka, V.; Gillet, P.

    2015-12-01

    Carbon storage and flux in the deep Earth are moderated by oxygen fugacity and interactions with iron-bearing phases. The amount of carbon stored in Earth's mantle versus the core depends on carbon-iron chemistry at the core-mantle boundary. Oxidized carbonates subducted from Earth's surface to the lowermost mantle may encounter reduced Fe0 metal from disproportionation of Fe2+ in lower mantle silicates or mixing with the core. To understand the fate of carbonates in the lowermost mantle, we have performed experiments on sandwiches of single-crystal (Ca0.6Mg0.4)CO3 dolomite and Fe foil in the laser-heated diamond anvil cell at lower mantle conditions of 49-110 GPa and 1800-2500 K. Syntheses were conducted with in situ synchrotron X-ray diffraction to identify phase assemblages. After quench to ambient conditions, samples were sectioned with a focused Ga+ ion beam for composition analysis with transmission electron microscopy. At the centers of the heated spots, iron melted and reacted completely with the carbonate to form magnesiowüstite, iron carbide, diamond, magnesium-rich carbonate and calcium carbonate. In samples heated at 49 and 64 GPa, the two carbonates exhibit a eutectoid texture. In the sample heated at 110 GPa, the carbonates form rounded ~150-nm-diameter grains with a higher modal proportion of interspersed diamonds. The presence of reduced iron in the deep lower mantle and core-mantle boundary region will promote the formation of diamonds in carbonate-bearing subducted slabs. The complete reaction of metallic iron to oxides and carbides in the presence of mantle carbonate supports the formation of these phases at the Earth's core-mantle boundary and in ultra-low velocity zones.

  4. High levels of microRNA-21 in the stroma of colorectal cancers predict short disease-free survival in stage II colon cancer patients

    DEFF Research Database (Denmark)

    Nielsen, Boye Schnack; Jørgensen, Stine; Fog, Jacob Ulrik

    2011-01-01

    Approximately 25% of all patients with stage II colorectal cancer will experience recurrent disease and subsequently die within 5 years. MicroRNA-21 (miR-21) is upregulated in several cancer types and has been associated with survival in colon cancer. In the present study we developed a robust...... in situ hybridization assay using high-affinity Locked Nucleic Acid (LNA) probes that specifically detect miR-21 in formalin-fixed paraffin embedded (FFPE) tissue samples. The expression of miR-21 was analyzed by in situ hybridization on 130 stage II colon and 67 stage II rectal cancer specimens. The mi...... relative to the nuclear density (TBR) obtained using a red nuclear stain. High TBR (and TB) estimates of miR-21 expression correlated significantly with shorter disease-free survival (p = 0.004, HR = 1.28, 95% CI: 1.06-1.55) in the stage II colon cancer patient group, whereas no significant correlation...

  5. The ruthenium isotopic composition of the oceanic mantle

    Science.gov (United States)

    Bermingham, K. R.; Walker, R. J.

    2017-09-01

    The approximately chondritic relative, and comparatively high absolute mantle abundances of the highly siderophile elements (HSE), suggest that their concentrations in the bulk silicate Earth were primarily established during a final ∼0.5 to 1% of ;late accretion; to the mantle, following the cessation of core segregation. Consequently, the isotopic composition of the HSE Ru in the mantle reflects an amalgamation of the isotopic compositions of late accretionary contributions to the silicate portion of the Earth. Among cosmochemical materials, Ru is characterized by considerable mass-independent isotopic variability, making it a powerful genetic tracer of Earth's late accretionary building blocks. To define the Ru isotopic composition of the oceanic mantle, the largest portion of the accessible mantle, we report Ru isotopic data for materials from one Archean and seven Phanerozoic oceanic mantle domains. A sample from a continental lithospheric mantle domain is also examined. All samples have identical Ru isotopic compositions, within analytical uncertainties, indicating that Ru isotopes are well mixed in the oceanic mantle, defining a μ100Ru value of 1.2 ± 7.2 (2SD). The only known meteorites with the same Ru isotopic composition are enstatite chondrites and, when corrected for the effects of cosmic ray exposure, members of the Main Group and sLL subgroup of the IAB iron meteorite complex which have a collective CRE corrected μ100Ru value of 0.9 ± 3.0. This suggests that materials from the region(s) of the solar nebula sampled by these meteorites likely contributed the dominant portion of late accreted materials to Earth's mantle.

  6. Mantle Circulation Models with variational data assimilation: Inferring past mantle flow and structure from plate motion histories and seismic tomography

    Science.gov (United States)

    Bunge, H.; Hagelberg, C.; Travis, B.

    2002-12-01

    EarthScope will deliver data on structure and dynamics of continental North America and the underlying mantle on an unprecedented scale. Indeed, the scope of EarthScope makes its mission comparable to the large remote sensing efforts that are transforming the oceanographic and atmospheric sciences today. Arguably the main impact of new solid Earth observing systems is to transform our use of geodynamic models increasingly from conditions that are data poor to an environment that is data rich. Oceanographers and meteorologists already have made substantial progress in adapting to this environment, by developing new approaches of interpreting oceanographic and atmospheric data objectively through data assimilation methods in their models. However, a similarly rigorous theoretical framework for merging EarthScope derived solid Earth data with geodynamic models has yet to be devised. Here we explore the feasibility of data assimilation in mantle convection studies in an attempt to fit global geodynamic model calculations explicitly to tomographic and tectonic constraints. This is an inverse problem not quite unlike the inverse problem of finding optimal seismic velocity structures faced by seismologists. We derive the generalized inverse of mantle convection from a variational approach and present the adjoint equations of mantle flow. The substantial computational burden associated with solutions to the generalized inverse problem of mantle convection is made feasible using a highly efficient finite element approach based on the 3-D spherical fully parallelized mantle dynamics code TERRA, implemented on a cost-effective topical PC-cluster (geowulf) dedicated specifically to large-scale geophysical simulations. This dedicated geophysical modeling computer allows us to investigate global inverse convection problems having a spatial discretization of less than 50 km throughout the mantle. We present a synthetic high-resolution modeling experiment to demonstrate that mid

  7. A network-based predictive gene-expression signature for adjuvant chemotherapy benefit in stage II colorectal cancer.

    Science.gov (United States)

    Cao, Bangrong; Luo, Liping; Feng, Lin; Ma, Shiqi; Chen, Tingqing; Ren, Yuan; Zha, Xiao; Cheng, Shujun; Zhang, Kaitai; Chen, Changmin

    2017-12-13

    The clinical benefit of adjuvant chemotherapy for stage II colorectal cancer (CRC) is controversial. This study aimed to explore novel gene signature to predict outcome benefit of postoperative 5-Fu-based therapy in stage II CRC. Gene-expression profiles of stage II CRCs from two datasets with 5-Fu-based adjuvant chemotherapy (training dataset, n = 212; validation dataset, n = 85) were analyzed to identify the indicator. A systemic approach by integrating gene-expression and protein-protein interaction (PPI) network was implemented to develop the predictive signature. Kaplan-Meier curves and Cox proportional hazards model were used to determine the survival benefit of adjuvant chemotherapy. Experiments with shRNA knock-down were carried out to confirm the signature identified in this study. In the training dataset, we identified 44 PPI sub-modules, by which we separate patients into two clusters (1 and 2) having different chemotherapeutic benefit. A predictor of 11 PPI sub-modules (11-PPI-Mod) was established to discriminate the two sub-groups, with an overall accuracy of 90.1%. This signature was independently validated in an external validation dataset. Kaplan-Meier curves showed an improved outcome for patients who received adjuvant chemotherapy in Cluster 1 sub-group, but even worse survival for those in Cluster 2 sub-group. Similar results were found in both the training and the validation dataset. Multivariate Cox regression revealed an interaction effect between 11-PPI-Mod signature and adjuvant therapy treatment in the training dataset (RFS, p = 0.007; OS, p = 0.006) and the validation dataset (RFS, p = 0.002). From the signature, we found that PTGES gene was up-regulated in CRC cells which were more resistant to 5-Fu. Knock-down of PTGES indicated a growth inhibition and up-regulation of apoptotic markers induced by 5-Fu in CRC cells. Only a small proportion of stage II CRC patients could benefit from adjuvant therapy. The 11-PPI-Mod as

  8. The basal part of the Oman ophiolitic mantle: a fossil Mantle Wedge?

    Science.gov (United States)

    Prigent, Cécile; Guillot, Stéphane; Agard, Philippe; Godard, Marguerite; Chauvet, Alain; Dubacq, Benoit; Monié, Patrick; Yamato, Philippe

    2014-05-01

    Although the Oman ophiolite is classically regarded as being the direct analog of oceanic lithosphere created at fast spreading ridges, the geodynamic context of its formation is still highly debated. The other alternative end-member model suggests that this ophiolite entirely formed in a supra-subduction zone setting. Fluids involved in the hydration of the oceanic lithosphere and in the presence of a secondary boninitic and andesitic volcanism may provide a way to discriminate between these two interpretations: are they descending near-axis hydrothermal fluxes (first model) or ascending from a subducting slab (second model)? We herein focus on the base of the ophiolitic mantle in order to characterize the origin of fluids and decipher hydration processes. Samples were taken along hecto- to kilometre-long sections across the basal banded unit directly overlying the amphibolitic/granulitic metamorphic sole. We carried out a petrological, structural and geochemical study on these rocks and their constitutive minerals. Our results show that, unlike the generally refractory character of Oman harzburgites, all the basal mantle rocks display secondary crystallization of clinopyroxene and amphibole through metasomatic processes. The microstructures and the chronology of these secondary mineralizations (clinopyroxene, pargasitic amphibole, antigorite and then lizardite/chrysotile) suggest that these basal rocks have been affected by cooling from mantle temperatures (serpentines (B, Sr, Rb, Ba, As), are consistent with amphibolite-derived fluids (Ishikawa et al., 2005) and cannot be easily explained by other sources. Based on these observations, we propose a geodynamic model in which intense and continuous metasomatism of the cooling base of the ophiolitic mantle is due to the release of fluids coming from the progressive dehydration of underlying amphibolitic rocks. This process is compatible with the progressive subduction of the Arabian margin during the Upper

  9. Atlas of the underworld: Slab remnants in the mantle, their sinking history, and a new outlook on lower mantle viscosity

    Science.gov (United States)

    van der Meer, Douwe G.; van Hinsbergen, Douwe J. J.; Spakman, Wim

    2018-01-01

    Across the entire mantle we interpret 94 positive seismic wave-speed anomalies as subducted lithosphere and associate these slabs with their geological record. We document this as the Atlas of the Underworld, also accessible online at www.atlas-of-the-underworld.org, a compilation comprising subduction systems active in the past 300 Myr. Deeper slabs are correlated to older geological records, assuming no relative horizontal motions between adjacent slabs following break-off, using knowledge of global plate circuits, but without assuming a mantle reference frame. The longest actively subducting slabs identified reach the depth of 2500 km and some slabs have impinged on Large Low Shear Velocity Provinces in the deepest mantle. Anomously fast sinking of some slabs occurs in regions affected by long-term plume rising. We conclude that slab remnants eventually sink from the upper mantle to the core-mantle boundary. The range in subduction-age versus - depth in the lower mantle is largely inherited from the upper mantle history of subduction. We find a significant depth variation in average sinking speed of slabs. At the top of the lower mantle average slab sinking speeds are between 10 and 40 mm/yr, followed by a deceleration to 10-15 mm/yr down to depths around 1600-1700 km. In this interval, in situ time-stationary sinking rates suggest deceleration from 20 to 30 mm/yr to 4-8 mm/yr, increasing to 12-15 mm/yr below 2000 km. This corroborates the existence of a slab deceleration zone but we do not observe long-term (> 60 My) slab stagnation, excluding long-term stagnation due to compositional effects. Conversion of slab sinking profiles to viscosity profiles shows the general trend that mantle viscosity increases in the slab deceleration zone below which viscosity slowly decreases in the deep mantle. This is at variance with most published viscosity profiles that are derived from different observations, but agrees qualitatively with recent viscosity profiles suggested

  10. Effects of iron on the lattice thermal conductivity of Earth's deep mantle and implications for mantle dynamics.

    Science.gov (United States)

    Hsieh, Wen-Pin; Deschamps, Frédéric; Okuchi, Takuo; Lin, Jung-Fu

    2018-04-17

    Iron may critically influence the physical properties and thermochemical structures of Earth's lower mantle. Its effects on thermal conductivity, with possible consequences on heat transfer and mantle dynamics, however, remain largely unknown. We measured the lattice thermal conductivity of lower-mantle ferropericlase to 120 GPa using the ultrafast optical pump-probe technique in a diamond anvil cell. The thermal conductivity of ferropericlase with 56% iron significantly drops by a factor of 1.8 across the spin transition around 53 GPa, while that with 8-10% iron increases monotonically with pressure, causing an enhanced iron substitution effect in the low-spin state. Combined with bridgmanite data, modeling of our results provides a self-consistent radial profile of lower-mantle thermal conductivity, which is dominated by pressure, temperature, and iron effects, and shows a twofold increase from top to bottom of the lower mantle. Such increase in thermal conductivity may delay the cooling of the core, while its decrease with iron content may enhance the dynamics of large low shear-wave velocity provinces. Our findings further show that, if hot and strongly enriched in iron, the seismic ultralow velocity zones have exceptionally low conductivity, thus delaying their cooling.

  11. Light Stable Isotopic Compositions of Enriched Mantle Sources: Resolving the Dehydration Paradox

    Science.gov (United States)

    Dixon, J. E.; Bindeman, I. N.; Kingsley, R. H.

    2017-12-01

    An outstanding puzzle in mantle geochemistry has been the origin and evolution of Earth's volatile components. The "dehydration paradox" refers to the following conundrum. Mantle compositions for some enriched mid-ocean ridge (MORB) and ocean island (OIB) basalts basalts require involvement of a mostly dehydrated slab component to explain the trace element ratios and radiogenic isotopic compositions, but a fully hydrated slab component to explain the stable isotopic compositions. Volatile and stable isotopic data on enriched MORB show a diversity of enriched components. Pacific PREMA-type basalts (H2O/Ce = 215 ± 30, δDSMOW = -45 ± 5 ‰) are similar to those in the north Atlantic (H2O/Ce = 220 ± 30; δDSMOW = -30 to -40 ‰). Basalts with EM-type signatures have regionally variable volatile compositions. North Atlantic EM-type basalts are wetter (H2O/Ce = 330 ± 30) and have isotopically heavier hydrogen (δDSMOW = -57 ± 5 ‰) than north Atlantic MORB. South Atlantic EM-type basalts are damp (H2O/Ce = 120 ± 10) with intermediate δDSMOW (-68 ± 2 ‰), similar to dDSMOW for Pacific MORB. North EPR EM-type basalts are dry (H2O/Ce = 110 ± 20) and isotopically light (δDSMOW = -94 ± 3 ‰). Boron and lithium isotopic ratios parallel the trends observed for dDSMOW. A multi-stage metasomatic and melting model accounts for the origin of the enriched components by extending the subduction factory concept down through the mantle transition zone, with slab temperature a key variable. The dehydration paradox is resolved by decoupling of volatiles from lithophile elements, reflecting primary dehydration of the slab followed by secondary rehydration and re-equilibration by fluids derived from subcrustal hydrous phases (e.g., antigorite) in cooler, deeper parts of the slab. The "expanded subduction factory" model includes melting at several key depths, including 1) 180 to 280 km, where EM-type mantle compositions are generated above slabs with average to hot thermal

  12. Early mantle differentiation: constraint from {sup 146}Sm-{sup 142}Nd systematics; Radioactivite eteinte du {sup 146}Sm et differenciation precoce du manteau terrestre

    Energy Technology Data Exchange (ETDEWEB)

    Caro, G

    2005-07-15

    We present new ultra-high precision {sup 142}Nd/{sup 144}Nd measurements of early Archaean rocks using the new generation thermal ionization mass spectrometer TRITON. Repeated measurements of the Ames Nd standard demonstrate that the {sup 142}Nd/{sup 144}Nd ratio can be determined with external precision of 2 ppm (2s), allowing confident resolution of anomalies as small as 5 ppm. A major analytical improvement lies in the elimination of the double normalization procedure required to correct our former measurements from a secondary mass fractionation effect. Our new results indicate that metasediments, meta-basalts and orthogneisses from the 3.6 - 3.8 Ga West Greenland craton display positive {sup 142}Nd anomalies ranging from 8 to 15 ppm. Using a simple two-stage model with initial e{sup 143}Nd value of 1.9 {+-} 0.6 e-units, coupled {sup 147}Sm-{sup 143}Nd and {sup 146}Sm-{sup 142}Nd chronometry constrains mantle differentiation to 50 to 200 Ma after formation of the solar system. This chronological constraint is consistent with differentiation of the Earth's mantle during the late stage of crystallization of a magma ocean. We have developed a two-box model describing {sup 142}Nd and {sup 143}Nd isotopic evolution of depleted mantle during the subsequent evolution of the crust-mantle system. Our results indicate that early terrestrial proto-crust had a lifetime of ca. 500 Ma in order to produce the observed Nd isotope signature of Archaean rocks. In the context of this two box mantle-crust system, we model the evolution of isotopic and chemical heterogeneity of depleted mantle as a function of the mantle stirring time. Using the dispersion of {sup 142}Nd/{sup 144}Nd and {sup 143}Nd/{sup 144}Nd ratios observed in early Archaean rocks, we constrain the stirring time of early Earth's mantle to 100 - 150 Ma, a factor of 5 to 10 shorter than stirring time inferred from modern oceanic basalts. (author)

  13. The mantle cells lymphoma: a proposed treatment

    International Nuclear Information System (INIS)

    Chavez Martinez, Marlene Elizabeth

    2012-01-01

    A literature review was performed on mantle cells lymphoma in the therapeutic schemes. The literature that has been used is published in journals of medicine specializing in hematology, oncology, radiation therapy, molecular biology and internal medicine. The literature review was performed to propose a scheme of treatment according to Costa Rica. Epigenetic alterations have been revealed in patients with mantle lymphoma on current researches. The mantle lymphoma pathology has been described in various forms of clinical and histological presentation, stressing the importance of detailing the different methods and diagnostic reports. Working groups have proposed and developed various chemotherapy regimens and concluded that CHOP alone is without effect in mantle cell lymphoma unlike R-hyper-CVAD, CHOP / DHAP, high-dose Ara-C. Researchers have tried to develop new treatments based vaccines, use of modified viruses, specific monoclonal antibodies. The classic treatment has been triple intrathecal therapy. The central nervous system has been one of the most momentous sites of mantle cell lymphoma infiltration because poorer patient prognosis [es

  14. [Cytostructure of the mantle zone in lymphatic tissue].

    Science.gov (United States)

    Bednár, B

    1993-04-01

    Four cellular layers of the follicular mantle zone in palatine tonsil lymphatic tissue were studied by electron microscopy after simultaneous immunophenotypical investigation. The first layer of the mantle zone consisting of small blastic cells was analogous to the small (centrocytoid) blastic layer of germinal centres. The second B monocytoid layer was lacking analogy in basic series of lymphocytes and seemed to be an independent morphological and probably functional unit. Plasmacytoid and clarocellular elements in outer layers of follicular mantle zone were in a way similar to T plasmacytoid and clarocellular components of Sézary syndrome infiltrates but considering transitional forms they had a local origin from incompletely transformed elements of B monocytoid layer. Inner follicular mantle zone was discussed as a source of incompletely transformed B lymphocytes for further mantle layers where their immunophenotypical modulation is taking place according to actual need. Outer mantle layers are aggressive against damaged epithelial and litoral structures and may be instrumental in a common reaction of B and T components.

  15. Axillary radiotherapy in conservative surgery for early-stage breast cancer (stage I and II).

    Science.gov (United States)

    García Novoa, Alejandra; Acea Nebril, Benigno; Díaz, Inma; Builes Ramírez, Sergio; Varela, Cristina; Cereijo, Carmen; Mosquera Oses, Joaquín; López Calviño, Beatriz; Seoane Pillado, María Teresa

    2016-01-01

    Several clinical studies analyze axillary treatment in women with early-stage breast cancer because of changes in the indication for axillary lymph node dissection. The aim of the study is to analyze the impact of axillary radiotherapy in disease-free and overall survival in women with early breast cancer treated with lumpectomy. Retrospective study in women with initial stages of breast carcinoma treated by lumpectomy. A comparative analysis of high-risk women with axillary lymph node involvement who received axillary radiotherapy with the group of women with low risk without radiotherapy was performed. Logistic regression was used to determine factors influencing survival and lymphedema onset. A total of 541 women were included in the study: 384 patients (71%) without axillary lymph node involvement and 157 women (29%) with 1-3 axillary lymph node involvement. Patients with axillary radiotherapy had a higher number of metastatic lymph node compared to non-irradiated (1.6±0.7 vs. 1.4±0.6, P=.02). The group of women with axillary lymph node involvement and radiotherapy showed an overall and disease-free survival at 10 years similar to that obtained in patients without irradiation (89.7% and 77.2%, respectively). 3 lymph nodes involved multiplied by more than 7 times the risk of death (HR=7.20; 95% CI: 1.36 to 38.12). The multivariate analysis showed axillary lymph node dissection as the only variable associated with the development of lymphedema. The incidence of axillary relapse on stage I and II breast cancer is rare. In these patients axillary radiotherapy does not improve overall survival, but contributes to regional control in those patients with risk factors. Copyright © 2016 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. Survival analysis of patients with clinical stages I or II Hodgkin's disease who have relapsed after initial treatment with radiotherapy alone

    DEFF Research Database (Denmark)

    Horwich, A.; Specht, L.; Ashley, S.

    1997-01-01

    relapse included initial stage, age, sex, histology, number of involved areas, mediastinal involvement, E-lesions, B-symptoms, erythrocyte sedimentation rate, alkaline phosphatase, serum albumin and haemoglobin. As well as presentation variables, we analysed the disease-free interval after initial......To aid treatment choice in early stage of Hodgkin's disease, we analysed patients registered in the IDHD Database with clinical stages I or II Hodgkin's disease who were not staged with laparotomy and whose initial treatment was with radiotherapy alone. The factors analysed for outcome after first...... radiotherapy and the extent of disease at relapse. A total of 1364 patients with clinical stage I or II Hodgkin's disease were treated with initial radiotherapy, of whom 473 relapsed. The probability of survival 10 years after relapse was 63%. For cause-specific survival (CSS), both multivariate and univariate...

  17. Temperature Profile of the Upper Mantle

    International Nuclear Information System (INIS)

    Anderson, O.L.

    1980-01-01

    Following the procedure outlined by Magnitsky [1971], thermal profiles of the upper mantle are computed by deriving the thermal gradient from the seismic data given as dv/sub s//drho used along with the values of (dv/sub s//dT9/sub p/ and (dv/sub s//dP)/sub T/ of selected minerals, measured at high temperature. The resulting values of dT/dZ are integrated from 380 km upward toward the surface, where the integrating constant is taken from Akagi and Akimoto's work, T=1400 0 C at 380 km. The resulting geotherms for minerals are used to derive geotherms for an eclogite mantle and a lherzolite mantle, with and without partial melting in the low-velocity zone. The geotherms are all subadiabatic, and some are virtually isothermal in the upper mantle. Some are characterized by a large thermal hump at the lithosphere boundary

  18. Adherence to treatment guidelines and survival for older patients with stage II or III colon cancer in Texas from 2001 through 2011.

    Science.gov (United States)

    Zhao, Hui; Zhang, Ning; Ho, Vivian; Ding, Minming; He, Weiguo; Niu, Jiangong; Yang, Ming; Du, Xianglin L; Zorzi, Daria; Chavez-MacGregor, Mariana; Giordano, Sharon H

    2018-02-15

    Treatment guidelines for colon cancer recommend colectomy with lymphadenectomy of at least 12 lymph nodes for patients with stage I to stage III disease as surgery adherence (SA) and adjuvant chemotherapy for individuals with stage III disease. Herein, the authors evaluated adherence to these guidelines among older patients in Texas with colon cancer and the associated survival outcomes. Using Texas Cancer Registry data linked with Medicare data, the authors included patients with AJCC stage II and III colon cancer who were aged ≥66 years and diagnosed between 2001 and 2011. SA and adjuvant chemotherapy adherence rates to treatment guidelines were estimated. The chi-square test, general linear regression, survival probability, and Cox regression were used to identify factors associated with adherence and survival. The rate of SA increased from 47.2% to 84% among 6029 patients with stage II or stage III disease from 2001 to 2011, and the rate of adjuvant chemotherapy increased from 48.9% to 53.1% for patients with stage III disease during the same time period. SA was associated with marital status, tumor size, surgeon specialty, and year of diagnosis. Patient age, sex, marital status, Medicare state buy-in status, comorbidity status, and year of diagnosis were found to be associated with adjuvant chemotherapy. The 5-year survival probability for patients receiving guideline-concordant treatment was the highest at 87% for patients with stage II disease and was 73% for those with stage III disease. After adjusting for demographic and tumor characteristics, improved cancer cause-specific survival was associated with the receipt of stage-specific, guideline-concordant treatment for patients with stage II or stage III disease. The adherence to guideline-concordant treatment among older patients with colon cancer residing in Texas improved over time, and was associated with better survival outcomes. Future studies should be focused on identifying interventions to

  19. Predictive value of pretreatment lymphocyte count in stage II colorectal cancer and in high-risk patients treated with adjuvant chemotherapy.

    Science.gov (United States)

    Liang, Lei; Zhu, Ji; Jia, Huixun; Huang, Liyong; Li, Dawei; Li, Qingguo; Li, Xinxiang

    2016-01-05

    Pretreatment lymphocyte count (LC) has been associated with prognosis and chemotherapy response in several cancers. The predictive value of LC for stage II colorectal cancer (CRC) and for high-risk patients treated with adjuvant chemotherapy (AC) has not been determined. A retrospective review of prospectively collected data from 1332 consecutive stage II CRC patients who underwent curative tumor resection was conducted. A pretreatment LC value risk, 459 (62.2%) of whom received AC. Patients with low LCs had significantly worse 5-year OS (74.6% vs. 90.2%, p risk patients with low LCs had the poorest DFS (p value or combined with high-risk status were both independent prognostic factors(p risk, AC-treated patients with high LCs had significantly longer DFS than untreated patients (HR, 0.594; 95% CI, 0.364-0.970; p = 0.035). There was no difference or trend for DFS or OS in patients with low LCs, regardless of the use of AC (DFS, p = 0.692; OS, p = 0.522). Low LC was also independently associated with poorer DFS in high-risk, AC-treated patients (HR, 1.885; 95% CI, 1.112-3.196; p = 0.019). Pretreatment LC is an independent prognostic factor for survival in stage II CRC. Furthermore, pretreatment LC reliably predicts chemotherapeutic efficacy in high-risk patients with stage II CRC.

  20. Recovery in stages I and II of thermal and fission neutron irradiated molybdenum

    International Nuclear Information System (INIS)

    Coltman, R.R. Jr.; Klabunde, C.E.; Redman, J.K.

    1975-01-01

    The influence of initial dose and irradiation doping upon the recovery of Mo was studied for the markedly different types of damage produced by thermal and fission neutrons. The features of the Stage I recovery commonly seen for several fcc metals can be identified, including a I/sub D/ peak at 40 0 K. The typical dose-dependent behavior of a I/sub E/ subpeak was observed at approximately 47 0 K, and evidence for free interstitial migration is further supported by irradiation doping results. Stage II shows a first-order peak at 120 0 K in which the population percentage increases with increasing initial dose in opposite fashion to fcc impurity detrapping peaks. (auth)

  1. Adjuvant therapy in stage I and stage II epithelial ovarian cancer. Results of two prospective randomized trials

    International Nuclear Information System (INIS)

    Young, R.C.; Walton, L.A.; Ellenberg, S.S.; Homesley, H.D.; Wilbanks, G.D.; Decker, D.G.; Miller, A.; Park, R.; Major, F. Jr.

    1990-01-01

    About a third of patients with ovarian cancer present with localized disease; despite surgical resection, up to half the tumors recur. Since it has not been established whether adjuvant treatment can benefit such patients, we conducted two prospective, randomized national cooperative trials of adjuvant therapy in patients with localized ovarian carcinoma. All patients underwent surgical resection plus comprehensive staging and, 18 months later, surgical re-exploration. In the first trial, 81 patients with well-differentiated or moderately well differentiated cancers confined to the ovaries (Stages Iai and Ibi) were assigned to receive either no chemotherapy or melphalan (0.2 mg per kilogram of body weight per day for five days, repeated every four to six weeks for up to 12 cycles). After a median follow-up of more than six years, there were no significant differences between the patients given no chemotherapy and those treated with melphalan with respect to either five-year disease-free survival or overall survival. In the second trial, 141 patients with poorly differentiated Stage I tumors or with cancer outside the ovaries but limited to the pelvis (Stage II) were randomly assigned to treatment with either melphalan (in the same regimen as above) or a single intraperitoneal dose of 32P (15 mCi) at the time of surgery. In this trial (median follow-up, greater than 6 years) the outcomes for the two treatment groups were similar with respect to five-year disease-free survival (80 percent in both groups) and overall survival (81 percent with melphalan vs. 78 percent with 32P; P = 0.48). We conclude that in patients with localized ovarian cancer, comprehensive staging at the time of surgical resection can serve to identify those patients (as defined by the first trial) who can be followed without adjuvant chemotherapy

  2. Tomography of core-mantle boundary and lowermost mantle coupled by geodynamics: joint models of shear and compressional velocity

    Directory of Open Access Journals (Sweden)

    Gaia Soldati

    2015-03-01

    Full Text Available We conduct joint tomographic inversions of P and S travel time observations to obtain models of delta v_P  and delta v_S in the entire mantle. We adopt a recently published method which takes into account the geodynamic coupling between mantle heterogeneity and core-mantle boundary (CMB topography by viscous flow, where sensitivity of the seismic travel times to the CMB is accounted for implicitly in the inversion (i.e. the CMB topography is not explicitly inverted for. The seismic maps of the Earth's mantle and CMB topography that we derive can explain the inverted seismic data while being physically consistent with each other. The approach involved scaling P-wave velocity (more sensitive to the CMB to density anomalies, in the assumption that mantle heterogeneity has a purely thermal origin, so that velocity and density heterogeneity are proportional to one another. On the other hand, it has sometimes been suggested that S-wave velocity might be more directly sensitive to temperature, while P heterogeneity is more strongly influenced by chemical composition. In the present study, we use only S-, and not P-velocity, to estimate density heterogeneity through linear scaling, and hence the sensitivity of core-reflected P phases to mantle structure. Regardless of whether density is more closely related to P- or S-velocity, we think it is worthwhile to explore both scaling approaches in our efforts to explain seismic data. The similarity of the results presented in this study to those obtained by scaling P-velocity to density suggests that compositional anomaly has a limited impact on viscous flow in the deep mantle.

  3. Estimation of Water Within the Lithospheric Mantle of Central Tibet from Petrological-Geophysical Investigations

    Science.gov (United States)

    Vozar, J.; Fullea, J.; Jones, A. G.

    2013-12-01

    Investigations of the lithosphere and sub-lithospheric upper mantle by integrated petrological-geophysical modeling of magnetotelluric (MT) and seismic surface-wave data, which are differently sensitive to temperature and composition, allows us to reduce the uncertainties associated with modeling these two data sets independently, as commonly undertaken. We use selected INDEPTH MT data, which have appropriate dimensionality and large penetration depths, across central Tibet for 1D modeling. Our deep resistivity models from the data can be classified into two different and distinct groups: (i) the Lhasa Terrane and (ii) the Qiangtang Terrane. For the Lhasa Terrane group, the models show the existence of upper mantle conductive layer localized at depths of 200 km, whereas for the Qiangtang Terrane, this conductive layer is shallower at depths of 120 km. We perform the integrated geophysical-petrological modeling of the MT and surface-wave data using the software package LitMod. The program facilitates definition of realistic temperature and pressure distributions within the upper mantle for given thermal structure and oxide chemistry in the CFMAS system. This allows us to define a bulk geoelectric and seismic model of the upper mantle based on laboratory and xenolith data for the most relevant mantle minerals, and to compute synthetic geophysical observables. Our results suggest an 80-120 km-thick, dry lithosphere in the central part of the Qiangtang Terrane. In contrast, in the central Lhasa Terrane the predicted MT responses are too resistive for a dry lithosphere regardless its thickness; according to seismic and topography data the expected lithospheric thickness is about 200 km. The presence of small amounts of water significantly decreases the electrical resistivity of mantle rocks and is required to fit the MT responses. We test the hypothesis of small amounts of water (ppm scale) in the nominally anhydrous minerals of the lithospheric mantle. Such a small

  4. OPTIMISATION OF MANTLE TANKS FOR LOW FLOW SOLAR HEATING SYSTEMS

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Furbo, Simon

    1996-01-01

    A model, describing the heat transfer coefficients in the mantle of a mantle tank has been developed. The model is validated by means of measurements with varying operational conditions for different designed mantle tanks. The model has been implemented in an existing detailed mathematical...... with the programme and by means of tests of three SDHW systems with different designed mantle tanks. Based on the investigations design rules for mantle tanks are proposed. The model, describing the heat transfer coefficients in the mantle is approximate. In addition, the measurements have revealed...... that a temperature stratification in the hot water tank, above the mantle is built up. This phenomenon may be important, but it is not taken into calculation in the programme. Therefore, theoretical and practical work is continuing in order to make a more precise model for the whole mantle tank....

  5. Mantle structure and tectonic history of SE Asia

    Science.gov (United States)

    Hall, Robert; Spakman, Wim

    2015-09-01

    Seismic travel-time tomography of the mantle under SE Asia reveals patterns of subduction-related seismic P-wave velocity anomalies that are of great value in helping to understand the region's tectonic development. We discuss tomography and tectonic interpretations of an area centred on Indonesia and including Malaysia, parts of the Philippines, New Guinea and northern Australia. We begin with an explanation of seismic tomography and causes of velocity anomalies in the mantle, and discuss assessment of model quality for tomographic models created from P-wave travel times. We then introduce the global P-wave velocity anomaly model UU-P07 and the tectonic model used in this paper and give an overview of previous interpretations of mantle structure. The slab-related velocity anomalies we identify in the upper and lower mantle based on the UU-P07 model are interpreted in terms of the tectonic model and illustrated with figures and movies. Finally, we discuss where tomographic and tectonic models for SE Asia converge or diverge, and identify the most important conclusions concerning the history of the region. The tomographic images of the mantle record subduction beneath the SE Asian region to depths of approximately 1600 km. In the upper mantle anomalies mainly record subduction during the last 10 to 25 Ma, depending on the region considered. We interpret a vertical slab tear crossing the entire upper mantle north of west Sumatra where there is a strong lateral kink in slab morphology, slab holes between c.200-400 km below East Java and Sumbawa, and offer a new three-slab explanation for subduction in the North Sulawesi region. There is a different structure in the lower mantle compared to the upper mantle and the deep structure changes from west to east. What was imaged in earlier models as a broad and deep anomaly below SE Asia has a clear internal structure and we argue that many features can be identified as older subduction zones. We identify remnants of slabs

  6. Role of mantle flow in Nubia-Somalia plate divergence

    Science.gov (United States)

    Stamps, D. S.; Iaffaldano, G.; Calais, E.

    2015-01-01

    Present-day continental extension along the East African Rift System (EARS) has often been attributed to diverging sublithospheric mantle flow associated with the African Superplume. This implies a degree of viscous coupling between mantle and lithosphere that remains poorly constrained. Recent advances in estimating present-day opening rates along the EARS from geodesy offer an opportunity to address this issue with geodynamic modeling of the mantle-lithosphere system. Here we use numerical models of the global mantle-plates coupled system to test the role of present-day mantle flow in Nubia-Somalia plate divergence across the EARS. The scenario yielding the best fit to geodetic observations is one where torques associated with gradients of gravitational potential energy stored in the African highlands are resisted by weak continental faults and mantle basal drag. These results suggest that shear tractions from diverging mantle flow play a minor role in present-day Nubia-Somalia divergence.

  7. Hf isotope evidence for a hidden mantle reservoir

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Simonetti, A.; Stevenson, R.K.

    2002-01-01

    High-precision Hf isotopic analyses and U-Pb ages of carbonatites and kimberlites from Greenland and eastern North America, including Earth's oldest known carbonatite (3 Ga), indicate derivation from an enriched mantle source. This previously unidentified mantle reservoir-marked by an unradiogenic...... Hf isotopic composition and preserved in the deep mantle for at least 3 b.y.-may account for the mass imbalance in Earth's Hf-Nd budget. The Hf isotopic data presented here support a common mantle source region and genetic link between carbonatite and some oceanic-island basalt volcanoes....

  8. The Earth's heterogeneous mantle a geophysical, geodynamical, and geochemical perspective

    CERN Document Server

    Khan, Amir

    2015-01-01

    This book highlights and discusses recent developments that have contributed to an improved understanding of observed mantle heterogeneities and their relation to the thermo-chemical state of Earth's mantle, which ultimately holds the key to unlocking the secrets of the evolution of our planet. This series of topical reviews and original contributions address 4 themes. Theme 1 covers topics in geophysics, including global and regional seismic tomography, electrical conductivity and seismic imaging of mantle discontinuities and heterogeneities in the upper mantle, transition zone and lower mantle. Theme 2 addresses geochemical views of the mantle including lithospheric evolution from analysis of mantle xenoliths, composition of the deep Earth and the effect of water on subduction-zone processes. Theme 3 discusses geodynamical perspectives on the global thermo-chemical structure of the deep mantle. Theme 4 covers application of mineral physics data and phase equilibrium computations to infer the regional-scale ...

  9. SEM investigation of incandescent lamp mantle structure on durability

    International Nuclear Information System (INIS)

    Gerneke, D.; Lang, C.

    2002-01-01

    Full text: The incandescent mantle as used on pressure and non-pressure liquid fuel lamps has been in use for over 100 years. What remains unexplained is the way in which the resistance to mechanical shock and the decline in tensile strength with usage is experienced. It has been suggested that to improve durability it is necessary to continuously burn a new mantle for the first two to three hours. The known factors in mantle durability and mechanical strength are chemical composition and fabric weave. This study was undertaken to investigate the effects of burning time and temperature on thorium oxide mantles. The operating temperature of mantles on a range of kerosene pressure lamps was measured and found to be between 800 and 1100 deg C. Heat treatments of thorium based Coleman mantles were carried out in a laboratory furnace within these ranges of temperatures for periods ranging from 2 minutes to 2 hours. The mantles were then viewed in a LEO S440 analytical SEM. Results at 800 deg C show a distinct change in surface morphology with increasing exposure time. At the shorter times (2-5 minutes) the surface was relatively smooth. With increased time periods (15 - 120 minutes) the surface was observed to have a large lumpy structure. At 1100 deg C the difference in surface morphology was not apparent between the shortest and longest times. The surface appears much smoother and no lumpy structure was observed. This suggests that when a mantle is operated at the higher temperature of 1100 deg C the structure of the Thorium oxide is quickly transformed into the known stronger amorphous form. This is taken as the observed smooth structure seen in the SEM images of the 1100 deg C samples. Thus the mantle is expected to be more resistant to mechanical shock and have increased durability. Practical field test results confirm these observations. The mantle on a lamp that is operating efficiently, burns brightly, will far outlast a mantle on an inefficient lamp which bums

  10. The prognostic importance of miR-21 in stage II colon cancer: a population-based study

    DEFF Research Database (Denmark)

    Kjaer-Frifeldt, S.; Hansen, T. F.; Nielsen, B. S.

    2012-01-01

    that increasing miR-21 expression levels were significantly correlated to decreasing RF-CSS. Further investigations of the clinical importance of miR-21 in the selection of high-risk stage II colon cancer patients are merited. British Journal of Cancer (2012) 107, 1169-1174. doi:10.1038/bjc.2012.365 www......BACKGROUND: Despite several years of research and attempts to develop prognostic models a considerable fraction of stage II colon cancer patients will experience relapse within few years from their operation. The aim of the present study was to investigate the prognostic importance of miRNA-21 (mi......-free cancer-specific survival (RF-CSS): HR = 1.26; 95% CI: 1.15-1.60; P importance and was found to be significantly related to poor RF-CSS: HR 1.41; 95% CI: 1.19-1.67; P

  11. Geochemical characteristics of Antarctic magmatism connected with Karoo-Maud and Kerguelen mantle plumes

    Science.gov (United States)

    Sushchevskaya, Nadezhda; Krymsky, Robert; Belyatsky, Boris; Antonov, Anton; Migdisova, Natalya

    2013-04-01

    dykes of the Schirmacher Oasis and basalts and dolerites of the Queen Maud Land (180 Ma) are identical in petrology and geochemistry terms and supposedly could be interpreted as the manifestation of the Karoo-Maud plume activity in Antarctica [Sushchevskaya et al., 2012]. The spatial distribution of the dikes indicates the eastward spreading of the plume material from DML to the Schirmacher Oasis within at least 10 Ma (up to ~35 Ma, taking into account the uncertainty of age determination). On the other hand, the considerable duration and multistage character of plume magmatism related to the activity of the Karoo-Maud plume in Antarctica and Africa [Leat et al., 2007; Luttinen et al., 2002] may indicate that the Mesozoic dikes of the oasis correspond to a single stage of plume magmatism. On the basis of obtained isotopic data it has been determined two magmatic melt evolution trends for basalts from: Queen Maud Land - Kerguelen Archipelago - Afanasy Nikitin Rise (Indian Ocean) and Jetty - Schirmacher oasises which mantle sources are quite different. Thus the Jetty - Schirmacher oasises magmatic melt sources are characterized by prevalence of the matter of moderately enriched or primitive chondritic mantle source and lithospheric mantle of Proterozoic ages but the substances of depleted mantle source similar to MORB-type and ancient mantle are absent. New data obtained on Nd, Sr, Pb isotopic and lithophile elements compositions of the alkaline-ultrabasic rocks from the Jetty oasis and Gaussberg volcano completed imagine of the Kerguelen-plume evolution. It has been confirmed unique character of the alkaline lamproiites of the Gaussberg volcano enrichments. Highly radiogenic Sr and Pb isotope ratios of these lamproiites reflect melting of the ancient sublithospheric depleted mantle which was stored from the Archean till nowadays unaffected by metasomatic-enrichment processes. During modern melting of this mantle part there is input of additional substances (crustal fluid

  12. Radiation doses from radioactivity in incandescent mantles

    International Nuclear Information System (INIS)

    1985-01-01

    Thorium nitrate is used in the production of incandescent mantles for gas lanterns. In this report dose estimates are given for internal and external exposure that result from the use of the incandescent mantles for gas lanterns. The collective, effective dose equivalent for all users of gas mantles is estimated to be about 100 Sv per annum in the Netherlands. For the population involved (ca. 700,000 persons) this is roughly equivalent to 5% to 10% of the collective dose equivalent associated with exposure to radiation from natural sources. The major contribution to dose estimates comes from inhalation of radium during burning of the mantles. A pessimistic approach results in individual dose estimates for inhalation of up to 0.2 mSv. Consideration of dose consequences in case of a fire in a storage department learns that it is necessary for emergency personnel to wear respirators. It is concluded that the uncontrolled removal of used gas mantles to the environment (soil) does not result in a significant contribution to environmental radiation exposure. (Auth.)

  13. Definitive radiation therapy for medically inoperable patients with stage I and II non-small cell lung cancer

    International Nuclear Information System (INIS)

    Hayakawa, K.; Mitsuhashi, N.; Saito, Y.; Nakayama, Y.; Katano, S.; Furuta, M.; Sakurai, H.; Takahashi, T.; Niibe, H.

    1995-01-01

    Purpose: To evaluate the role of definitive radiation therapy (RT) in the treatment for medically inoperable patients with stage I-II non-small cell lung cancer (NSCLC). Materials and Methods: From 1976 through 1989, 84 patients with clinical stage I and II NSCLC were treated with definitive RT alone at Gunma University hospital. All patients were treated with 10 MV X-rays using antero-posterior parallel opposed fields. The total dose ranged from 60 Gy to 90 Gy (35 pts; 60-69 Gy, 39 pts; 70-74 Gy, 10 pts; ≥ 80 Gy) with once-daily standard fractionation. Results: The two and five-year survival rates were 74% and 31% for 28 patients with stage I disease, as compared with 40% and 19% for 56 patients with stage II respectively (p<0.05). Although there was no significant difference of survival rates by the histologic subtypes, in the patients with squamous cell carcinoma there were more long-term survivors. Fifty-three patients with tumors less than 5 cm in diameter had an infield progression rate of 14% at two years, in comparison with 38% of 31 patients with tumors greater than 5 cm (p<0.05). Overall distant failure occurred in 57% of the patients with smaller tumors and in 80% of the patients with larger tumors (p<0.05). The difference of survival rates for these two groups was statistically significant (p<0.005). Ten patients given a total dose of 80Gy or over had only 17% local progression at the time of last follow-up, however they had not been alive beyond three years because they developed pulmonary insufficiency due to severe stenosis of the proximal bronchus. For age and sex, there were no significant differences in survival, however, patients with performance status of 0-1 lived longer than those with a status of 2 or more (MST 24 versus 13 months; p=0.06). Conclusion: The tumor size was the most important factor not only for local control but also for distant failure. It was also suggested that the optimal radiation dose for medically inoperable stage I-II

  14. European Lithospheric Mantle; geochemical, petrological and geophysical processes

    Science.gov (United States)

    Ntaflos, Th.; Puziewicz, J.; Downes, H.; Matusiak-Małek, M.

    2017-04-01

    The second European Mantle Workshop occurred at the end of August 2015, in Wroclaw, Poland, attended by leading scientists in the study the lithospheric mantle from around the world. It built upon the results of the first European Mantle Workshop (held in 2007, in Ferrara, Italy) published in the Geological Society of London Special Publication 293 (Coltorti & Gregoire, 2008).

  15. A mantle plume model for the Equatorial Highlands of Venus

    Science.gov (United States)

    Kiefer, Walter S.; Hager, Bradford H.

    1991-01-01

    The possibility that the Equatorial Highlands are the surface expressions of hot upwelling mantle plumes is considered via a series of mantle plume models developed using a cylindrical axisymmetric finite element code and depth-dependent Newtonian rheology. The results are scaled by assuming whole mantle convection and that Venus and the earth have similar mantle heat flows. The best model fits are for Beta and Atla. The common feature of the allowed viscosity models is that they lack a pronounced low-viscosity zone in the upper mantle. The shape of Venus's long-wavelength admittance spectrum and the slope of its geoid spectrum are also consistent with the lack of a low-viscosity zone. It is argued that the lack of an asthenosphere on Venus is due to the mantle of Venus being drier than the earth's mantle. Mantle plumes may also have contributed to the formation of some smaller highland swells, such as the Bell and Eistla regions and the Hathor/Innini/Ushas region.

  16. Pillars of the Mantle

    KAUST Repository

    Pugmire, David

    2017-07-05

    In this work, we investigate global seismic tomographic models obtained by spectral-element simulations of seismic wave propagation and adjoint methods. Global crustal and mantle models are obtained based on an iterative conjugate-gradient type of optimization scheme. Forward and adjoint seismic wave propagation simulations, which result in synthetic seismic data to make measurements and data sensitivity kernels to compute gradient for model updates, respectively, are performed by the SPECFEM3D-GLOBE package [1] [2] at the Oak Ridge Leadership Computing Facility (OLCF) to study the structure of the Earth at unprecedented levels. Using advances in solver techniques that run on the GPUs on Titan at the OLCF, scientists are able to perform large-scale seismic inverse modeling and imaging. Using seismic data from global and regional networks from global CMT earthquakes, scientists are using SPECFEM3D-GLOBE to understand the structure of the mantle layer of the Earth. Visualization of the generated data sets provide an effective way to understand the computed wave perturbations which define the structure of mantle in the Earth.

  17. Re-Os Isotopic Constraints on the Chemical Evolution and Differentiation of the Martian Mantle

    Science.gov (United States)

    Brandon, Alan D.; Walker, Richard J.

    2002-01-01

    subsequent inefficient mixing between these reservoirs. These data show that models for the origin of isotopic variation for SNC meteorites require at least two long-lived mantle reservoirs, and possibly three. The range in the projected present day gamma(sub Os) of these reservoirs is from -5.4+/-2.6, to +4+/-1. The isotopic systematics of these reservoirs may be linked to development of cumulate crystal piles in a Martian magma ocean and variable amounts of late stage intercumulus melt. In this model, fractional crystallization of olivine and possibly other phases with slightly subchondritic Re/Os, from a solidifying magma ocean, resulted in a lower Re/Os ratio early cumulates, and a resultant low gamma(sub Os). Later cumulates or evolved melts crystallized with higher Re/Os ratios to produce the mantle reservoir(s) with consequent higher gamma(sub Os). Crystallization of the Martian magma ocean followed earliest core formation, as indicated by the correlation of epsilon(sub W) with epsilon(sub 142Nd) and initial gamma(sub Os).

  18. Receptor units responding to movement in the octopus mantle.

    Science.gov (United States)

    Boyle, P R

    1976-08-01

    1. A preparation of the mantle of Octopus which is inverted over a solid support and which exposes the stellate ganglion and associated nerves is described. 2. Afferent activity can be recorded from stellar nerves following electrical stimulation of the pallial nerve. The latency and frequency of the phasic sensory response is correlated with the contraction of the mantle musculature. 3. It is proposed that receptors cells located in the muscle, and their activity following mantle contraction, form part of a sensory feedback system in the mantle. Large, multipolar nerve cells that were found between the two main layers of circular muscle in the mantle could be such receptors.

  19. Validation of the 12-gene colon cancer recurrence score as a predictor of recurrence risk in stage II and III rectal cancer patients.

    Science.gov (United States)

    Reimers, Marlies S; Kuppen, Peter J K; Lee, Mark; Lopatin, Margarita; Tezcan, Haluk; Putter, Hein; Clark-Langone, Kim; Liefers, Gerrit Jan; Shak, Steve; van de Velde, Cornelis J H

    2014-11-01

    The 12-gene Recurrence Score assay is a validated predictor of recurrence risk in stage II and III colon cancer patients. We conducted a prospectively designed study to validate this assay for prediction of recurrence risk in stage II and III rectal cancer patients from the Dutch Total Mesorectal Excision (TME) trial. RNA was extracted from fixed paraffin-embedded primary rectal tumor tissue from stage II and III patients randomized to TME surgery alone, without (neo)adjuvant treatment. Recurrence Score was assessed by quantitative real time-polymerase chain reaction using previously validated colon cancer genes and algorithm. Data were analysed by Cox proportional hazards regression, adjusting for stage and resection margin status. All statistical tests were two-sided. Recurrence Score predicted risk of recurrence (hazard ratio [HR] = 1.57, 95% confidence interval [CI] = 1.11 to 2.21, P = .01), risk of distant recurrence (HR = 1.50, 95% CI = 1.04 to 2.17, P = .03), and rectal cancer-specific survival (HR = 1.64, 95% CI = 1.15 to 2.34, P = .007). The effect of Recurrence Score was most prominent in stage II patients and attenuated with more advanced stage (P(interaction) ≤ .007 for each endpoint). In stage II, five-year cumulative incidence of recurrence ranged from 11.1% in the predefined low Recurrence Score group (48.5% of patients) to 43.3% in the high Recurrence Score group (23.1% of patients). The 12-gene Recurrence Score is a predictor of recurrence risk and cancer-specific survival in rectal cancer patients treated with surgery alone, suggesting a similar underlying biology in colon and rectal cancers. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Can Lower Mantle Slab-like Seismic Anomalies be Explained by Thermal Coupling Between the Upper and Lower Mantles?

    NARCIS (Netherlands)

    Cízková, H. (Hana); Cadek, O.; Berg, A.P. van den; Vlaar, N.J.

    1999-01-01

    Below subduction zones, high resolution seismic tomographic models resolve fast anomalies that often extend into the deep lower mantle. These anomalies are generally interpreted as slabs penetrating through the 660-km seismic discontinuity, evidence in support of whole-mantle convection. However,

  1. Mantle superplumes induce geomagnetic superchrons

    Directory of Open Access Journals (Sweden)

    Peter eOlson

    2015-07-01

    Full Text Available We use polarity reversal systematics from numerical dynamos to quantify the hypothesis that the modulation of geomagnetic reversal frequency, including geomagnetic superchrons, results from changes in core heat flux related to growth and collapse of lower mantle superplumes. We parameterize the reversal frequency sensitivity from numerical dynamos in terms of average core heat flux normalized by the difference between the present-day core heat flux and the core heat flux at geomagnetic superchron onset. A low-order polynomial fit to the 0-300 Ma Geomagnetic Polarity Time Scale (GPTS reveals that a decrease in core heat flux relative to present-day of approximately 30% can account for the Cretaceous Normal Polarity and Kiaman Reverse Polarity Superchrons, whereas the hyper-reversing periods in the Jurassic require a core heat flux equal to or higher than present-day. Possible links between GPTS transitions, large igneous provinces (LIPs, and the two lower mantle superplumes are explored. Lower mantle superplume growth and collapse induce GPTS transitions by increasing and decreasing core heat flux, respectively. Age clusters of major LIPs postdate transitions from hyper-reversing to superchron geodynamo states by 30-60 Myr, suggesting that superchron onset may be contemporaneous with LIP-forming instabilities produced during collapses of lower mantle superplumes.

  2. Rheological properties of the lower crust and upper mantle beneath Baja California: a microstructural study of xenoliths from San Quintin

    Science.gov (United States)

    Van der Werf, Thomas F.; Chatzaras, Vasileios; Tikoff, Basil; Drury, Martyn R.

    2016-04-01

    Baja California is an active transtensional rift zone, which links the San Andreas Fault with the East Pacific Rise. The erupted basalts of the Holocene San Quintin volcanic field contain xenoliths, which sample the lower crust and upper mantle beneath Baja California. The aim of this research is to gain insight in the rheology of the lower crust and the upper mantle by investigating the xenolith microstructure. Microstructural observations have been used to determine the dominant deformation mechanisms. Differential stresses were estimated from recrystallized grain size piezometry of plagioclase and clinopyroxene for the lower crust and olivine for the upper mantle. The degree of deformation can be inferred from macroscopic foliations and the deformation microstructures. Preliminary results show that both the lower crust and the upper mantle have been affected by multiple stages of deformation and recrystallization. In addition the dominant deformation mechanism in both the lower crust and the upper mantle is dislocation creep based on the existence of strong crystallographic preferred orientations. The differential stress estimates for the lower crust are 10-29 MPa using plagioclase piezometry and 12-35 MPa using clinopyroxene piezometry. For the upper mantle, differential stress estimates are 10-20 MPa. These results indicate that the strength of the lower crust and the upper mantle are very similar. Our data do not fit with the general models of lithospheric strength and may have important implications for the rheological structure of the lithosphere in transtensional plate margins and for geodynamic models of the region.

  3. High accuracy mantle convection simulation through modern numerical methods

    KAUST Repository

    Kronbichler, Martin

    2012-08-21

    Numerical simulation of the processes in the Earth\\'s mantle is a key piece in understanding its dynamics, composition, history and interaction with the lithosphere and the Earth\\'s core. However, doing so presents many practical difficulties related to the numerical methods that can accurately represent these processes at relevant scales. This paper presents an overview of the state of the art in algorithms for high-Rayleigh number flows such as those in the Earth\\'s mantle, and discusses their implementation in the Open Source code Aspect (Advanced Solver for Problems in Earth\\'s ConvecTion). Specifically, we show how an interconnected set of methods for adaptive mesh refinement (AMR), higher order spatial and temporal discretizations, advection stabilization and efficient linear solvers can provide high accuracy at a numerical cost unachievable with traditional methods, and how these methods can be designed in a way so that they scale to large numbers of processors on compute clusters. Aspect relies on the numerical software packages deal.II and Trilinos, enabling us to focus on high level code and keeping our implementation compact. We present results from validation tests using widely used benchmarks for our code, as well as scaling results from parallel runs. © 2012 The Authors Geophysical Journal International © 2012 RAS.

  4. Lead Isotopes in Olivine-Phyric Shergottite Tissint: Implications for the Geochemical Evolution of the Shergottite Source Mantle

    Science.gov (United States)

    Moriwaki, R.; Usui, T.; Simon, J. I.; Jones, J. H.; Yokoyama, T.

    2015-01-01

    Geochemically-depleted shergottites are basaltic rocks derived from a martian mantle source reservoir. Geochemical evolution of the martian mantle has been investigated mainly based on the Rb-Sr, Sm-Nd, and Lu-Hf isotope systematics of the shergottites [1]. Although potentially informative, U-Th- Pb isotope systematics have been limited because of difficulties in interpreting the analyses of depleted meteorite samples that are more susceptible to the effects of near-surface processes and terrestrial contamination. This study conducts a 5-step sequential acid leaching experiment of the first witnessed fall of the geochemically-depleted olivinephyric shergottite Tissint to minimize the effect of low temperature distrubence. Trace element analyses of the Tissint acid residue (mostly pyroxene) indicate that Pb isotope compositions of the residue do not contain either a martian surface or terrestrial component, but represent the Tissint magma source [2]. The residue has relatively unradiogenic initial Pb isotopic compositions (e.g., 206Pb/204Pb = 10.8136) that fall within the Pb isotope space of other geochemically-depleted shergottites. An initial µ-value (238U/204Pb = 1.5) of Tissint at the time of crystallization (472 Ma [3]) is similar to a time-integrated mu- value (1.72 at 472 Ma) of the Tissint source mantle calculated based on the two-stage mantle evolution model [1]. On the other hand, the other geochemically-depleted shergottites (e.g., QUE 94201 [4]) have initial µ-values of their parental magmas distinctly lower than those of their modeled source mantle. These results suggest that only Tissint potentially reflects the geochemical signature of the shergottite mantle source that originated from cumulates of the martian magma ocean

  5. Sources and timing of pyroxenite formation in the sub-arc mantle: Case study of the Cabo Ortegal Complex, Spain

    Science.gov (United States)

    Tilhac, Romain; Grégoire, Michel; O'Reilly, Suzanne Y.; Griffin, William L.; Henry, Hadrien; Ceuleneer, Georges

    2017-09-01

    Pyroxenites exposed in ophiolites and orogenic peridotite massifs may record petrogenetic processes occurring in mantle domains generated and/or transferred in supra-subduction environments. However, the timing of their formation and the geochemical characteristics of their source region commonly are obscured by metamorphic and metasomatic overprints. This is especially critical in arc-related environments, where pyroxenites may be formed during the differentiation of primitive magmas. Our approach combines Sr- and Nd-isotope geochemistry and geochronology, and modelling of REE diffusion, to further constrain the origin of a well-characterized set of pyroxenites from the arc-related Cabo Ortegal Complex, Spain. In the light of petrological constraints, Sr- and Nd-isotope systematics consistently indicate that cpx and amphibole have acquired disequilibrium during two main episodes: (1) a magmatic/metasomatic episode that led to the formation of the pyroxenites, coeval with that of Cabo Ortegal granulites and corresponding to the incipient stage of a potential Cadomian arc (459-762 Ma; isochron and second-stage Nd model ages); (2) an episode of metamorphic amphibolitization upon the percolation of relatively unradiogenic and LREE-enriched hydrous fluids, subsequent to the delamination of the pyroxenites from their arc-root settings during Devonian subduction. Calculations of diffusional timescale for the re-equilibration of REE are consistent with this scenario but provide only poor additional constraints due to the sensitivity of this method to grain size and sub-solidus temperature. We thus emphasize the necessity to combine isochron ages and Nd model ages corrected for radiogenic ingrowth to put time constraints on the formation of subduction- and/or collision-related pyroxenites, along with petrological and geochemical constraints. Homogeneous age-corrected 143Nd/144Nd of 0.5121-0.5125 (εNd between 0 and +7.5) and 87Sr/86Sr of 0.7037-0.7048 provide information

  6. Traveltime Dispersion in an Isotropic Elastic Mantle: Dominance of the Lower Mantle Signal in Differential-frequency Time Residuals

    Science.gov (United States)

    Schuberth, B. S. A.; Zaroli, C.; Nolet, G.

    2014-12-01

    We study wavefield effects in elastic isotropic 3-D seismic structures derived from the temperature field of a high resolution mantle circulation model. More specifically, we quantify the structural dispersion of traveltime residuals of direct P- and S-waves in a model with realistic length-scales and magnitudes of the variations in seismic velocities and density. 3-D global wave propagation is simulated using a spectral element method, and traveltime residuals are measured in four different frequency bands by cross-correlation of 3-D and 1-D synthetic waveforms. Intrinsic (dissipative) attenuation is deliberately neglected, so that any variation of traveltimes with frequency can be attributed to structural effects. Additional simulations are performed for a model in which 3-D structure is removed in the upper 800 km to isolate the dispersion signal of the lower mantle. One question that we address is whether the structural length-scales inherent to a vigorously convecting mantle give rise to significant body-wave dispersion. In our synthetic dataset, the difference between long-period and short-period traveltime residuals generally increases with increasing short-period residual. However, we do not find an exact linear dependence, and in case of P-waves even non-monotonic behaviour. At largest short-period residuals, average dispersion is on the order of 2 s for both P- and S-waves and even larger when structure is confined to the lower mantle. Dispersion also appears to be asymmetric; that is, larger for negative than for positive residuals. The standard deviations of both P- and S-wave residuals also increase with increasing period and we discuss possible explanations for this behaviour. Overall, wavefield effects in both models are generally stronger for P-waves than for S-waves at the same frequencies. We also find that for certain combinations of periods, the difference between the respective residuals is very similar between the "whole mantle" and the "lower

  7. Deep mantle seismic heterogeneities in Western Pacific subduction zones

    Science.gov (United States)

    Bentham, H. L. M.; Rost, S.

    2012-04-01

    In recent years array seismology has been used extensively to image the small scale (~10 km) structure of the Earth. In the mantle, small scale structure likely represents chemical heterogeneity and is essential in our understanding of mantle convection and especially mantle mixing. As subduction is the main source of introducing crustal material into the Earth's mantle, it is of particular interest to track the transport of subducted crust through the mantle to resolve details of composition and deformation of the crust during the subduction process. Improved knowledge of subduction can help provide constraints on the mechanical mixing process of crustal material into the ambient mantle, as well as constraining mantle composition and convection. This study uses seismic array techniques to map seismic heterogeneities associated with Western Pacific subduction zones, where a variety of slab geometries have been previously observed. We use seismic energy arriving prior to PP, a P-wave underside reflection off the Earth's surface halfway between source and receiver, to probe the mantle for small-scale heterogeneities. PP precursors were analysed at Eielson Array (ILAR), Alaska using the recently developed Toolkit for Out-of-Plane Coherent Arrival Tracking (TOPCAT) algorithm. The approach combines the calculated optimal beampower and an independent semblance (coherency) measure, to improve the signal-to-noise ratio of coherent arrivals. 94 earthquakes with sufficient coherent precursory energy were selected and directivity information of the arrivals (i.e. slowness and backazimuth) was extracted from the data. The scattering locations for 311 out-of-plane precursors were determined by ray-tracing and minimising the slowness, backazimuth and differential travel time misfit. Initial analyses show that deep scattering (>1000 km) occurs beneath the Izu-Bonin subduction zone, suggesting that subducted crust does continue into the lower mantle in this location. Other

  8. Granisetron, Aprepitant, and Dexamethasone in Preventing Nausea and Vomiting in Patients Receiving Chemotherapy for Stage II, III, or IV Ovarian Cancer

    Science.gov (United States)

    2018-04-24

    Nausea and Vomiting; Ovarian Brenner Tumor; Ovarian Clear Cell Cystadenocarcinoma; Ovarian Endometrioid Adenocarcinoma; Ovarian Mucinous Cystadenocarcinoma; Ovarian Seromucinous Carcinoma; Ovarian Serous Cystadenocarcinoma; Stage II Ovarian Cancer; Stage IIA Fallopian Tube Cancer; Stage IIA Ovarian Cancer; Stage IIB Fallopian Tube Cancer; Stage IIB Ovarian Cancer; Stage IIC Fallopian Tube Cancer; Stage IIC Ovarian Cancer; Stage IIIA Fallopian Tube Cancer; Stage IIIA Ovarian Cancer; Stage IIIA Primary Peritoneal Cancer; Stage IIIB Fallopian Tube Cancer; Stage IIIB Ovarian Cancer; Stage IIIB Primary Peritoneal Cancer; Stage IIIC Fallopian Tube Cancer; Stage IIIC Ovarian Cancer; Stage IIIC Primary Peritoneal Cancer; Stage IV Fallopian Tube Cancer; Stage IV Ovarian Cancer; Stage IV Primary Peritoneal Cancer; Undifferentiated Ovarian Carcinoma

  9. Developing a Crustal and Upper Mantle Velocity Model for the Brazilian Northeast

    Science.gov (United States)

    Julia, J.; Nascimento, R.

    2013-05-01

    Development of 3D models for the earth's crust and upper mantle is important for accurately predicting travel times for regional phases and to improve seismic event location. The Brazilian Northeast is a tectonically active area within stable South America and displays one of the highest levels of seismicity in Brazil, with earthquake swarms containing events up to mb 5.2. Since 2011, seismic activity is routinely monitored through the Rede Sismográfica do Nordeste (RSisNE), a permanent network supported by the national oil company PETROBRAS and consisting of 15 broadband stations with an average spacing of ~200 km. Accurate event locations are required to correctly characterize and identify seismogenic areas in the region and assess seismic hazard. Yet, no 3D model of crustal thickness and crustal and upper mantle velocity variation exists. The first step in developing such models is to refine crustal thickness and depths to major seismic velocity boundaries in the crust and improve on seismic velocity estimates for the upper mantle and crustal layers. We present recent results in crustal and uppermost mantle structure in NE Brazil that will contribute to the development of a 3D model of velocity variation. Our approach has consisted of: (i) computing receiver functions to obtain point estimates of crustal thickness and Vp/Vs ratio and (ii) jointly inverting receiver functions and surface-wave dispersion velocities from an independent tomography study to obtain S-velocity profiles at each station. This approach has been used at all the broadband stations of the monitoring network plus 15 temporary, short-period stations that reduced the inter-station spacing to ~100 km. We expect our contributions will provide the basis to produce full 3D velocity models for the Brazilian Northeast and help determine accurate locations for seismic events in the region.

  10. Thrombocytosis portends adverse prognostic significance in patients with stage II colorectal carcinoma [v2; ref status: indexed, http://f1000r.es/4k6

    Directory of Open Access Journals (Sweden)

    Tianhua Guo

    2014-10-01

    Full Text Available Thrombocytosis portends adverse prognostic significance in many types of cancers including ovarian and lung carcinoma. In this study, we determined the prevalence and prognostic significance of thrombocytosis (defined as platelet count in excess of 400 × 103/μl in patients with colorectal cancer. We performed a retrospective analysis of 310 consecutive patients diagnosed at our Institution between 2004 and 2013. The patients (48.7% male and 51.3% female had a mean age of 69.9 years (+/- 12.7 years at diagnosis. Thrombocytosis was found in a total of 25 patients, with a higher incidence in those with stage III and IV disease (14.4% of patients. Although the mean platelet count increased with the depth of tumor invasion (pT, its values remained within normal limits in the whole patient cohort. No patient with stage I cancer (n=57 had elevated platelet count at diagnosis. By contrast, five of the 78 patients (6.4% with stage II cancer showed thrombocytosis, and four of these patients showed early recurrence and/or metastatic disease, resulting in shortened survival (they died within one year after surgery. The incidence of thrombocytosis increased to 12.2% and 20.6%, respectively, in patients with stage III and IV disease. The overall survival rate of patients with thrombocytosis was lower than those without thrombocytosis in the stage II and III disease groups, but this difference disappeared in patients with stage IV cancer who did poorly regardless of their platelet count. We concluded that thrombocytosis at diagnosis indicates adverse clinical outcome in colorectal cancer patients with stage II or III disease. This observation is especially intriguing in stage II patients because the clinical management of these patients is controversial. If our data are confirmed in larger studies, stage II colon cancer patients with thrombocytosis may be considered for adjuvant chemotherapy.

  11. Spatial relationships between crustal structures and mantle seismicity in the Vrancea Seismogenic Zone of Romania: Implications for geodynamic evolution

    Science.gov (United States)

    Enciu, Dana-Mihaela

    Integration of active and passive-source seismic data is employed to study the relationships between crustal structures and seismicity in the SE Carpathian foreland of Romania, and the connection with the Vrancea Seismogenic Zone. Relocated crustal epicenters and focal mechanisms are correlated with industry seismic profiles Comanesti, Ramnicu Sarat, Braila and Buzau, the reprocessed DACIA PLAN profile and the DRACULA (Deep Reflection Acquisition Constraining Unusual Lithospheric Activity) II and III profiles in order to understand the link between neo-tectonic foreland deformation and Vrancea mantle seismicity. Projection of crustal foreland hypocenters onto deep seismic profiles identified active crustal faults suggesting a mechanical coupling between sedimentary, crustal and upper mantle structures on the Trotus, Sinaia and newly observed Ialomita Faults. Seismic reflection imaging revealed the absence of west dipping reflectors in the crust and an east dipping to horizontal Moho in the proximity of the Vrancea area. These findings argue against both 'subduction-in-place' and 'slab break-off' as viable mechanisms for generating Vrancea mantle seismicity.

  12. Breast-conserving therapy (BCT) in stage I-II synchronous bilateral breast cancer (SBBC)

    Energy Technology Data Exchange (ETDEWEB)

    Gollamudi, Smitha V; Gelman, Rebecca S; Peiro, Gloria; Schneider, Lindsey; Connolly, James L; Schnitt, Stuart; Silver, Barbara; Harris, Jay R

    1995-07-01

    PURPOSE: To determine whether patients with early-stage SBBC can be safely and effectively treated with bilateral BCT. MATERIALS and METHODS: We retrospectively reviewed records of 26 patients with clinical Stage I-II SBBC treated between 1968-1989 with bilateral BCT. SBBC was defined as tumors diagnosed no more than one month apart, with both sides demonstrating invasive cancer. Maximum (max) clinical stage was based on the more advanced breast tumor. Median age at diagnosis was 56 years (range, 32-85 years); menopausal status was 6 pre-, 16 post-, 3 peri-, and 1 unknown at diagnosis. Median follow-up for surviving pts is 95 months (range, 68-157). Outcome was compared to 1325 pts with unilateral Stage I or II breast cancer, within the same age range, treated during the same time period. There were no significant differences in median age, median total dose, tumor size, estrogen receptor (ER) status, pathologic nodal status, and use of systemic therapy between the study population and the comparison group. Local recurrence (LR) was evaluated as true recurrence (TR, i.e., in the original tumor bed), marginal miss (MM, at the edge of the boost field), or elsewhere (E). Median total dose to the primary was 6100 cGy (range, 5000-7000). Pathology was available for review in 19 cases. Cytology (nuclear and cytoplasmic features) was similar in (7(19)) evaluable cases, and architecture (growth pattern, ie, papillary, solid) was similar in (5(19)) cases. The presence of either cytologic or architectural similarity was noted in(9(19)) cases. 7 of 19 pts who had axillary lymph node evaluation on at least one side had pathological confirmation of lymph node metastasis. Stage was the same in both breasts in 13 cases (10 Stage I, 3 Stage II); ER status data was complete in 11 pts, and the same in both primaries in 9 cases. Cosmetic results and complications after BCT were scored. Statistical significance was evaluated by use of the Fisher exact test. RESULTS: The 5-yr actuarial

  13. Biomechanical Analysis of Cuboid Osteotomy Lateral Column Lengthening for Stage II B Adult-Acquired Flatfoot Deformity: A Cadaveric Study.

    Science.gov (United States)

    Zhou, Haichao; Ren, Haoyang; Li, Chunguang; Xia, Jiang; Yu, Guangrong; Yang, Yunfeng

    2017-01-01

    Purpose . To investigate the effect of cuboid osteotomy lateral column lengthening (LCL) for the correction of stage II B adult-acquired flatfoot deformity in cadaver. Methods . Six cadaver specimens were loaded to 350 N. Flatfoot models were established and each was evaluated radiographically and pedobarographically in the following conditions: (1) intact foot, (2) flatfoot, and (3) cuboid osteotomy LCL (2, 3, 4, and 5 mm). Results . Compared with the flatfoot model, the LCLs showed significant correction of talonavicular coverage on anteroposterior radiographs and talus-first metatarsal angle on both anteroposterior and lateral radiographs ( p stage II B adult-acquired flatfoot deformity with a 3 mm lengthening in cadavers.

  14. Mantle contamination and the Izu-Bonin-Mariana (IBM) 'high-tide mark': evidence for mantle extrusion caused by Tethyan closure

    Science.gov (United States)

    Flower, M. F. J.; Russo, R. M.; Tamaki, K.; Hoang, N.

    2001-04-01

    Western Pacific basins are characterized by three remarkable attributes: (1) complex kinematic histories linked to global-scale plate interactions; (2) DUPAL-like contaminated mantle; and (3) rapid post-Mesozoic rollback of the confining arc-trench systems. The coincidence of slab steepening, extreme arc curvature, and vigorous basin opening associated with the Mariana convergent margin suggests that rollback continues in response to an east-directed mantle 'wind'. Against a backdrop of conflicting kinematic and genetic interpretations we explore the notion that eastward asthenospheric flow driven by diachronous Tethyan closure caused stretching of eastern Eurasia and concomitant opening of western Pacific basins. Marking the eastern boundary of the latter, the Izu-Bonin-Mariana forearc may be regarded as a litho-tectonic 'high-tide mark' comprising igneous and metamorphic products from successive episodes (since ca. 45 Ma.) of arc sundering and backarc basin opening. The forearc also forms an isotopic boundary separating contaminated western Pacific mantle from the N-MORB Pacific Ocean reservoir. While the isotopic composition of western Pacific mantle resembles that feeding Indian Ocean hotspot and spreading systems, its spatial-temporal variation and the presence of subduction barriers to the south appear to preclude northward flow of Indian Ocean mantle and require an endogenous origin for sub-Eurasian contaminated mantle. It is concluded that the extrusion of Tethyan asthenosphere, contaminated by sub-Asian cratonic lithosphere, was a major cause of western Pacific arc rollback and basin opening. The model is consistent with paleomagnetic and geologic evidence supporting independent kinematic histories for constituent parts of the Philippine Sea and Sunda plates although interpretation of these is speculative. Compounded by effects of the Australia-Indonesia collision, late-Tethyan mantle extrusion appears to have produced the largest DUPAL domain in the

  15. Preface: Deep Slab and Mantle Dynamics

    Science.gov (United States)

    Suetsugu, Daisuke; Bina, Craig R.; Inoue, Toru; Wiens, Douglas A.

    2010-11-01

    We are pleased to publish this special issue of the journal Physics of the Earth and Planetary Interiors entitled "Deep Slab and Mantle Dynamics". This issue is an outgrowth of the international symposium "Deep Slab and Mantle Dynamics", which was held on February 25-27, 2009, in Kyoto, Japan. This symposium was organized by the "Stagnant Slab Project" (SSP) research group to present the results of the 5-year project and to facilitate intensive discussion with well-known international researchers in related fields. The SSP and the symposium were supported by a Grant-in-Aid for Scientific Research (16075101) from the Ministry of Education, Culture, Sports, Science and Technology of the Japanese Government. In the symposium, key issues discussed by participants included: transportation of water into the deep mantle and its role in slab-related dynamics; observational and experimental constraints on deep slab properties and the slab environment; modeling of slab stagnation to constrain its mechanisms in comparison with observational and experimental data; observational, experimental and modeling constraints on the fate of stagnant slabs; eventual accumulation of stagnant slabs on the core-mantle boundary and its geodynamic implications. This special issue is a collection of papers presented in the symposium and other papers related to the subject of the symposium. The collected papers provide an overview of the wide range of multidisciplinary studies of mantle dynamics, particularly in the context of subduction, stagnation, and the fate of deep slabs.

  16. Cephalometric evaluation of the effects of the Twin Block appliance in subjects with Class II, Division 1 malocclusion amongst different cervical vertebral maturation stages.

    Science.gov (United States)

    Khoja, Aisha; Fida, Mubassar; Shaikh, Attiya

    2016-06-01

    To evaluate the cephalometric changes in skeletal, dentoalveolar and soft tissue variables induced by Clark's Twin Block (CTB) in Class II, Division 1 malocclusion patients and to compare these changes in different cervical vertebral maturation stages. Pre- and post-treatment/observation lateral cephalograms of 53 Class II, Division 1 malocclusion patients and 60 controls were compared to evaluate skeletal, dentoalveolar and soft tissue changes. Skeletal maturity was assessed according to cervical vertebral maturation stages. Pre- and post-treatment/observation mean changes and differences (T2-T1) were compared by means of Wilcoxon sign rank and Mann-Whitney U-tests, respectively. Intergroup comparisons between different cervical stages were performed by means of Kruskal-Wallis test and Mann-Whitney U-test (p ≤ 0.05) . When compared with controls, there was a significant reduction in ANB angle (p cervical stages (p cervical stages (p cervical stages, significant differences were found for SNA, SNB and UI-SN angles and overjet. . The Twin-Block along with the normal craniofacial growth improves facial esthetics in Class II, Division 1 malocclusion by changes in underlying skeletal and dentoalveolar structures. The favorable mandibular growth occurs during any of the cervical vertebral maturation stages, with more pronounced effect during CS-3 stage.

  17. Primitive Mantle Nitrogen Revealed by SIMS in 3.5 Ga Harzburgitic Diamonds

    Science.gov (United States)

    Westerlund, K.; Richardson, S. H.; Shirey, S. B.; Hauri, E. H.; Gurney, J. J.

    2009-12-01

    The advent of the ion microprobe (SIMS) some 30 years ago marked the start of an exciting new approach to subcontinental lithospheric mantle (SCLM) studies. In-situ SIMS analysis of trace element zoning in mantle minerals, in combination with TIMS analysis of mineral separates, has revolutionized our understanding of equilibrium/disequilibrium relationships on a variety of time and length scales. For example, octahedral diamonds isolate mineral inclusions from diffusive exchange at mantle temperatures on a Gyr time scale, as well as preserving host diamond isotopic signatures that have long been used as indicators of the sources of diamond-forming fluids. Nitrogen, the main trace element in diamond, behaves as a compatible element during diamond growth [1] and SIMS has proved essential to determining C and N isotopic compositions on the scale of inclusions and associated diamond growth zones [2]. A suite of harzburgitic sulfide inclusion bearing diamonds from the 53 Ma Panda kimberlite, NWT, Canada, provides an ideal opportunity to characterize the source of diamond fluids in the world’s oldest macrodiamonds [3]. This suite gave a sulfide Re-Os isochron age of 3.52 ± 0.17 Ga with a radiogenic initial Os isotope signature characteristic of subduction-related fluids. The first-order variation in C (δ13C = -9 to 0‰) and N (δ15N = -25 to -7‰) isotopic composition of the host diamonds has been mapped by SIMS profiling of diamond plates. Collectively, the specimens show the following features: (i) compositional zoning/discontinuities indicating discrete growth stages and multiple fluids, (ii) overall core-to-rim decrease in N concentration variably well correlated with C and N isotopic composition, suggesting both open and closed system fractionation during diamond growth, (iii) initial N concentration correlated with N isotopic composition for different stones suggesting mixing of an ambient, isotopically light N component (<-26‰) and a heavier N component

  18. Xenoliths from Bunyaruguru volcanic field: Some insights into lithology of East African Rift upper mantle

    Science.gov (United States)

    Muravyeva, N. S.; Senin, V. G.

    2018-01-01

    The mineral composition of mantle xenoliths from kamafugites of the Bunyaruguru volcanic field has been determined. The major and some trace elements (Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, Cr, Ni, Ba, Sr, La, Ce, Nd, Nb) has been analyzed in olivine, clinopyroxene, phlogopite, Cr-spinel, titanomagnetite, perovskite and carbonates of xenoliths and their host lavas. Bunyaruguru is one of three (Katwe-Kikorongo, Fort Portal and Bunyaruguru) volcanic fields included in the Toro-Ankole province located on the North end of the West Branch of the East African Rift. The xenoliths from three craters within the Bunyaruguru volcanic field revealed the different character of metasomatic alteration, reflecting the heterogeneity of the mantle on the kilometer scale. The most unusual finding was composite glimmerite-wehrlite xenolith from the crater Kazimiro, which contains the fresh primary high-Mg olivine with inclusions of Cr-spinel that had not been previously identified in this area. The different composition of phenocryst and xenolith minerals indicates that the studied xenoliths are not cumulus of enclosing magma, but the composition of xenoliths characterizes the lithology of the upper mantle of the area. The carbonate melt inclusions in olivine Fo90 demonstrate the existence of primary carbonatitic magmas in Bunyaruguru upper mantle. The results of texture and chemical investigation of the xenolith minerals indicate the time sequence of metasomatic alteration of Bunyaruguru upper mantle: MARID metasomatism at the first stage followed by carbonate metasomatism. The abundances of REE in perovskites from kamafugite are 2-4 times higher than similar values for xenolith. Therefore the kamafugite magma was been generated from a more enriched mantle source than the source of the xenoliths. The evaluation of P-T conditions formation of clinopyroxene xenolith revealed the range of pressure 20-65 kbar and the temperatures range 830-1040 °C. The pressure of clinopyroxene phenocryst

  19. The uniquely high-temperature character of Cullinan diamonds: A signature of the Bushveld mantle plume?

    Science.gov (United States)

    Korolev, N. M.; Kopylova, M.; Bussweiler, Y.; Pearson, D. G.; Gurney, J.; Davidson, J.

    2018-04-01

    The mantle beneath the Cullinan kimberlite (formerly known as "Premier") is a unique occurrence of diamondiferous cratonic mantle where diamonds were generated contemporaneously and shortly following a mantle upwelling that led to the formation of a Large Igneous Province that produced the world's largest igneous intrusion - the 2056 Ma Bushveld Igneous Complex (BIC). We studied 332 diamond inclusions from 202 Cullinan diamonds to investigate mantle thermal effects imposed by the formation of the BIC. The overwhelming majority of diamonds come from three parageneses: (1) lithospheric eclogitic (69%), (2) lithospheric peridotitic (21%), and (3) sublithospheric mafic (9%). The lithospheric eclogitic paragenesis is represented by clinopyroxene, garnet, coesite and kyanite. Main minerals of the lithospheric peridotitic paragenesis are forsterite, enstatite, Cr-pyrope, Cr-augite and spinel; the sublithospheric mafic association includes majorite, CaSiO3 phases and omphacite. Diamond formation conditions were calculated using an Al-in-olivine thermometer, a garnet-clinopyroxene thermometer, as well as majorite and Raman barometers. The Cullinan diamonds may be unique on the global stage in recording a cold geotherm of 40 mW/m2 in cratonic lithosphere that was in contact with underlying convecting mantle at temperatures of 1450-1550 °C. The studied Cullinan diamonds contain a high proportion of inclusions equilibrated at temperatures exceeding the ambient 1327 °C adiabat, i.e. 54% of eclogitic diamonds and 41% of peridotitic diamonds. By contrast, ≤ 1% of peridotitic diamond inclusions globally yield equally high temperatures. We propose that the Cullinan diamond inclusions recorded transient, slow-dissipating thermal perturbations associated with the plume-related formation of the 2 Ga Bushveld igneous province. The presence of inclusions in diamond from the mantle transition zone at 300-650 km supports this view. Cullinan xenoliths indicative of the thermal state of

  20. Active and fossil mantle flows in the western Alpine region unravelled by seismic anisotropy analysis and high-resolution P wave tomography

    Science.gov (United States)

    Salimbeni, Simone; Malusà, Marco G.; Zhao, Liang; Guillot, Stéphane; Pondrelli, Silvia; Margheriti, Lucia; Paul, Anne; Solarino, Stefano; Aubert, Coralie; Dumont, Thierry; Schwartz, Stéphane; Wang, Qingchen; Xu, Xiaobing; Zheng, Tianyu; Zhu, Rixiang

    2018-04-01

    The anisotropy of seismic velocities in the mantle, when integrated with high-resolution tomographic models and geologic information, can be used to detect active mantle flows in complex plate boundary areas, providing new insights on the impact of mantle processes on the topography of mountain belts. Here we use a densely spaced array of temporary broadband seismic stations to analyze the seismic anisotropy pattern of the western Alpine region, at the boundary between the Alpine and Apenninic slabs. Our results are supportive of a polyphase development of anisotropic mantle fabrics, possibly starting from the Jurassic to present. Geophysical data presented in this work, and geologic evidence taken from the literature, indicate that: (i) fossil fabrics formed during Tethyan rifting may be still preserved within the Alpine and Apenninic slabs; (ii) mantle deformation during Apenninic slab rollback is not compensated by a complete toroidal flow around the northern tip of the retreating slab; (iii) the previously observed continuous trend of anisotropy fast axes near-parallel to the western Alpine arc is confirmed. We observe that this arc-parallel trend of fast axes is located in correspondence to a low velocity anomaly in the European upper mantle, beneath regions of the Western and Ligurian Alps showing the highest uplift rates. We propose that the progressive rollback of the Apenninic slab, in the absence of a counterclockwise toroidal flow at its northern tip, induced a suction effect at the scale of the supraslab mantle. The resulting mantle flow pattern was characterized by an asthenospheric counterflow at the rear of the unbroken Western Alps slab and around its southern tip, and by an asthenospheric upwelling, mirrored by low P wave velocities, that would have favored the topographic uplift of the Alpine belt from the Mont Blanc to the Mediterranean sea.

  1. Nacre formation by epithelial cell cultures from mantle of the black-lip pearl oyster, Pinctada margaritifera.

    Science.gov (United States)

    Jayasankar, Vidya; Vasudevan, Srinivasa Raghavan; Poulose, Suja C; Divipala, Indira

    2018-06-12

    Mantle tissue from the black-lip pearl oyster, Pinctada margaritifera, was cultured in vitro using sterilized seawater supplemented with 0.1% yeast extract as the culture medium. Granular and agranular epithelial cells, hyalinocytes, and fibroblast-like cells were observed in the initial stages of culture. Epithelial cells later formed pseudopodial cell networks containing clusters of granulated cells, which upon maturation released their colored granules. These granules induced formation of nacre crystal deposits on the bottom of the culture plate. Cultures comprised of only granulated epithelial cells were established through periodic sub-culturing of mantle cells and maintained for over 18 mo in a viable condition. Reverse transcriptase PCR of cultured cells demonstrated gene expression of the shell matrix protein, nacrein. To further evaluate the functional ability of cultured granulated epithelial cells, nuclear shell beads were incubated in culture medium containing these cells to induce nacre formation on the beads. Observation of the bead surface under a stereomicroscope at periodic intervals showed the gradual formation of blackish yellow colored nacre deposits. Examination of the bead surface by scanning electron microscopy and energy dispersive X-ray analysis at periodic intervals revealed a distinct brick and mortar formation characteristic of nacre, comprised of aragonite platelets and matrix proteins. Calcium, carbon, and oxygen were the major elements in all stages examined. Our study shows that mantle epithelial cells in culture retain the ability to secrete nacre and can therefore form the basis for future studies on the biomineralization process and its application in development of sustainable pearl culture.

  2. Whole-mantle P-wave velocity structure and azimuthal anisotropy

    Science.gov (United States)

    Yamamoto, Y.; Zhao, D.

    2009-12-01

    There are some hotspot volcanoes on Earth, such as Hawaii and Iceland. The mantle plume hypothesis was proposed forty years ago to explain hotspot volcanoes (e.g., Wilson, 1963; Morgan, 1971). Seismic tomography is a powerful technique to detect mantle plumes and determine their detailed structures. We determined a new whole-mantle 3-D P-wave velocity model (Tohoku model) using a global tomography method (Zhao, 2004, 2009). A flexible-grid approach with a grid interval of ~200 km is adopted to conduct the tomographic inversion. Our model shows that low-velocity (low-V) anomalies with diameters of several hundreds of kilometers are visible from the core-mantle boundary (CMB) to the surface under the major hotspot regions. Under South Pacific where several hotspots including Tahiti exist, there is a huge low-V anomaly from the CMB to the surface. This feature is consistent with the previous models. We conducted extensive resolution tests in order to understand whether this low-V anomaly shows a single superplume or a plume cluster. Unfortunately this problem is still not resolved because the ray path coverage in the mantle under South Pacific is not good enough. A network of ocean bottom seismometers is necessary to solve this problem. To better understand the whole-mantle structure and dynamics, we also conducted P-wave tomographic inversions for the 3-D velocity structure and azimuthal anisotropy. At each grid node there are three unknown parameters: one represents the isotropic velocity, the other two represent the azimuthal anisotropy. Our results show that in the shallow part of the mantle (Japan trench axis. In the Tonga subduction zone, the FVD is also perpendicular to the trench axis. Under the Tibetan region the FVD is NE-SW, which is parallel to the direction of the India-Asia collision. In the deeper part of the upper mantle and in the lower mantle, the amplitude of anisotropy is reduced. One interesting feature is that the FVD aligns in a radiated fashion

  3. Circulation of carbon dioxide in the mantle: multiscale modeling

    Science.gov (United States)

    Morra, G.; Yuen, D. A.; Lee, S.

    2012-12-01

    Much speculation has been put forward on the quantity and nature of carbon reservoirs in the deep Earth, because of its involvement in the evolution of life at the surface and inside planetary interiors. Carbon penetrates into the Earth's mantle mostly during subduction of oceanic crust, which contains carbonate deposits [1], however the form that it assumes at lower mantle depths is scarcely understood [2], hampering our ability to estimate the amount of carbon in the entire mantle by orders of magnitude. We present simulations of spontaneous degassing of supercritical CO2 using in-house developed novel implementations of the Fast-Multipole Boundary Element Method suitable for modeling two-phase flow (here mantle mineral and free CO2 fluid) through disordered materials such as porous rocks. Because the mutual interaction of droplets immersed either in a fluid or a solid matrix and their weakening effect to the host rock alters the strength of the mantle rocks, at the large scale the fluid phases in the mantle may control the creeping of mantle rocks [3]. In particular our study focuses on the percolation of supercritical CO2, estimated through the solution of the Laplace equation in a porous system, stochastically generated through a series of random Karhunen-Loeve decomposition. The model outcome is employed to extract the transmissivity of supercritical fluids in the mantle from the lowest scale up to the mantle scale and in combination with the creeping flow of the convecting mantle. The emerging scenarios on the global carbon cycle are finally discussed. [1] Boulard, E., et al., New host for carbon in the deep Earth. Proceedings of the National Academy of Sciences, 2011. 108(13): p. 5184-5187. [2] Walter, M.J., et al., Deep Mantle Cycling of Oceanic Crust: Evidence from Diamonds and Their Mineral Inclusions. Science, 2011. 334(6052): p. 54-57. [3] Morra, G., et al., Ascent of Bubbles in Magma Conduits Using Boundary Elements and Particles. Procedia Computer

  4. The expression of chemokine receptors CXCR3 and CXCR4 in predicting postoperative tumour progression in stages I-II colon cancer: a retrospective study.

    Science.gov (United States)

    Du, Changzheng; Yao, Yunfeng; Xue, Weicheng; Zhu, Wei-Guo; Peng, Yifan; Gu, Jin

    2014-01-01

    The prognostic significance of chemokine receptors in stage I/II colon cancer is unclear. We assessed the prognostic value of chemokine receptor CXCR3 and CXCR4 in stage I/II colon cancer. 145 patients with stage I/II colon cancer who underwent curative surgery alone from 2000 to 2007 were investigated. Chemokine receptor expression was assessed by immunohistochemistry. The associations between CXCR3, CXCR4 and clinicopathological variables were analysed using the χ2 test, and the relationships between chemokine receptors and a 5-year disease-free survival were analysed by univariate and multivariate analyses. The high-expression rates of CXCR3 and CXCR4 were 17.9% (26/145) and 38.6% (56/145), respectively. There were no significant associations between the expressions of CXCR3, CXCR4 and clinicopathological factors including gender, age, tumour location, histological differentiation, pathological stage, lymphovascular invasion and pretreatment serum carcinoembryonic antigen (CEA). The 5-year disease-free survival was not significantly different between low-expression groups and high-expression groups of CXCR3 and CXCR4. Multivariate analysis revealed that serum CEA and a number of retrieved lymph nodes, rather than chemokine receptors, were independent prognosticators. CXCR3 and CXCR4 are not independent prognosticators for stage I/II colon cancer after curative surgery.

  5. Water Distribution in the Continental and Oceanic Upper Mantle

    Science.gov (United States)

    Peslier, Anne H.

    2015-01-01

    Nominally anhydrous minerals such as olivine, pyroxene and garnet can accommodate tens to hundreds of ppm H2O in the form of hydrogen bonded to structural oxygen in lattice defects. Although in seemingly small amounts, this water can significantly alter chemical and physical properties of the minerals and rocks. Water in particular can modify their rheological properties and its distribution in the mantle derives from melting and metasomatic processes and lithology repartition (pyroxenite vs peridotite). These effects will be examined here using Fourier transform infrared spectrometry (FTIR) water analyses on minerals from mantle xenoliths from cratons, plume-influenced cratons and oceanic settings. In particular, our results on xenoliths from three different cratons will be compared. Each craton has a different water distribution and only the mantle root of Kaapvaal has evidence for dry olivine at its base. This challenges the link between olivine water content and survival of Archean cratonic mantle, and questions whether xenoliths are representative of the whole cratonic mantle. We will also present our latest data on Hawaii and Tanzanian craton xenoliths which both suggest the intriguing result that mantle lithosphere is not enriched in water when it interacts with melts from deep mantle upwellings (plumes).

  6. Climatic Evolution and Habitability of Terrestrial Planets: Perspectives from Coupled Atmosphere-Mantle Systems

    Science.gov (United States)

    Basu Sarkar, D.; Moore, W. B.

    2016-12-01

    A multitude of factors including the distance from the host star and the stage of planetary evolution affect planetary climate and habitability. The complex interactions between the atmosphere and dynamics of the deep interior of the planets along with stellar fluxes present a formidable challenge. This work employs simplified approaches to address these complex issues in a systematic way. To be specific, we are investigating the coupled evolution of atmosphere and mantle dynamics. The overarching goal here is to simulate the evolutionary history of the terrestrial planets, for example Venus, Earth and Mars. This research also aims at deciphering the history of Venus-like runaway greenhouse and thus explore the possibility of cataclysmic shifts in climate of Earth-like planets. We focus on volatile cycling within the solid planets to understand the role of carbon/water in climatic and tectonic outcomes of such planets. In doing so, we are considering the feedbacks in the coupled mantle-atmosphere system. The primary feedback between the atmosphere and mantle is the surface temperature established by the greenhouse effect, which regulates the temperature gradient that drives the mantle convection and controls the rate at which volatiles are exchanged through weathering. We start our models with different initial assumptions to determine the final climate outcomes within a reasonable parameter space. Currently, there are very few planetary examples, to sample the climate outcomes, however this will soon change as exoplanets are discovered and examined. Therefore, we will be able to work with a significant number of potential candidates to answer questions like this one: For every Earth is there one Venus? ten? a thousand?

  7. Mantle mixing and thermal evolution during Pangaea assembly and breakup

    Science.gov (United States)

    Rudolph, M. L.; Li, M.; Zhong, S.; Manga, M.

    2016-12-01

    Continents insulate the underlying mantle, and it has been suggested that the arrangement of the continents can have a significant effect on sub-continental mantle temperatures. Additionally, the dispersal or agglomeration of continents may affect the efficacy of continental insulation, with some studies suggesting warming of 100K beneath supercontinents. During the most recent supercontinent cycle, Pangaea was encircled by subduction, potentially creating a `curtain' of subducted material that may have prevented mixing of the sub-Pangaea mantle with the sub-Panthalassa mantle. Using 3D spherical shell geometry mantle convection simulations, we quantify the effect of insulation by continents and supercontinents. We explore the differences in model predictions for purely thermal vs. thermochemical convection, and we use tracers to quantify the exchange of material between the sub-oceanic to the sub-continental mantle.

  8. Reconstructing mantle heterogeneity with data assimilation based on the back-and-forth nudging method: Implications for mantle-dynamic fitting of past plate motions

    Science.gov (United States)

    Glišović, Petar; Forte, Alessandro

    2016-04-01

    The paleo-distribution of density variations throughout the mantle is unknown. To address this question, we reconstruct 3-D mantle structure over the Cenozoic era using a data assimilation method that implements a new back-and-forth nudging algorithm. For this purpose, we employ convection models for a compressible and self-gravitating mantle that employ 3-D mantle structure derived from joint seismic-geodynamic tomography as a starting condition. These convection models are then integrated backwards in time and are required to match geologic estimates of past plate motions derived from marine magnetic data. Our implementation of the nudging algorithm limits the difference between a reconstruction (backward-in-time solution) and a prediction (forward-in-time solution) on over a sequence of 5-million-year time windows that span the Cenozoic. We find that forward integration of reconstructed mantle heterogeneity that is constrained to match past plate motions delivers relatively poor fits to the seismic-tomographic inference of present-day mantle heterogeneity in the upper mantle. We suggest that uncertainties in the past plate motions, related for example to plate reorganization episodes, could partly contribute to the poor match between predicted and observed present-day heterogeneity. We propose that convection models that allow tectonic plates to evolve freely in accord with the buoyancy forces and rheological structure in the mantle could provide additional constraints on geologic estimates of paleo-configurations of the major tectonic plates.

  9. Tracing Mantle Plumes: Quantifying their Morphology and Behavior from Seismic Tomography

    Science.gov (United States)

    O'Farrell, K. A.; Eakin, C. M.; Jones, T. D.; Garcia, E.; Robson, A.; Mittal, T.; Lithgow-Bertelloni, C. R.; Jackson, M. G.; Lekic, V.; Rudolph, M. L.

    2016-12-01

    Hotspot volcanism provides a direct link between the deep mantle and the surface, but the location, depth and source of the mantle plumes that feed hotspots are highly controversial. In order to address this issue it is important to understand the journey along which plumes have travelled through the mantle. The general behavior of plumes in the mantle also has the potential to tell us about the vigor of mantle convection, net rotation of the mantle, the role of thermal versus chemical anomalies, and important bulk physical properties of the mantle such as the viscosity profile. To address these questions we developed an algorithm to trace plume-like features in shear-wave (Vs) seismic tomographic models based on picking local minima in velocity and searching for continuous features with depth. We apply this method to several of the latest tomographic models and can recover 30 or more continuous plume conduits that are >750 km long. Around half of these can be associated with a known hotspot at the surface. We study the morphology of these plume chains and find that the largest lateral deflections occur near the base of the lower mantle and in the upper mantle. We analyze the preferred orientation of the plume deflections and their gradient to infer large scale mantle flow patterns and the depth of viscosity contrasts in the mantle respectively. We also retrieve Vs profiles for our traced plumes and compare with velocity profiles predicted for different mantle adiabat temperatures. We use this to constrain the thermal anomaly associated with these plumes. This thermal anomaly is then converted to a density anomaly and an upwelling velocity is derived. We compare this to buoyancy fluxes calculated at the surface and use this in conjunction with our measured plume tilts/deflections to estimate the strength of the "mantle wind".

  10. Survival and Complication Rate of Radiation Therapy in Stage I and II Carcinoma of uterine Cervix

    International Nuclear Information System (INIS)

    Ma, Sun Young; Cho, Heung Lea; Sohn, Seung Chang

    1995-01-01

    Purpose : To analyze survival rate and late rectal and bladder complication for patients with stage with stage I and II carcinoma of uterine cervix treated by radiation alone or combined with chemotherapy. Materials and Methods : Between November 1984 and December 1993, 127 patients with stage I and II carcinoma of uterine cervix treated by radiation alone or combined therapy of radiation and chemotherapy. Retrospective analysis for survival rate was carried out on eligible 107 patients and review for complication was possible in 91 patients. The median follow-up was 47 months (range 3-118) and the median age of patients was 56 years (range 31-76). 26 patients were stage IB by FIGO classification. 40 were stage IIA and 41 were stage IIB. 86 cases were treated by radiation alone and 21 were treated by radiation and chemotherapy. 101 patients were treated with intracavitary radiation therapy (ICRT), of these, 80 were received low dose rate (LDR) ICRT and 21 were received high dose rate (HDR) ICRT. Of the patients who received LDR ICRT, 63 were treated by 1 intracavitary insertion and 17 were underwent 2 insertions. And we evaluated the external radiation dose and midline shield. Results : Acturial survival rate at 5 years was 92% for stage IB, 75% for stage IIA, 53% for stage IIB and 69% in all patients. Grade 1 rectal complications were developed in 20 cases(22%), grade 2 were in 22 cases (24%), 22 cases (24%) of grade 1 urinary complications and 17 cases (19%) of grade 2 urinary complications were observed But no patients had severe complications that needed surgical management or admission care. Maximum bladder dose for the group of patients with urinary complications was higher than that for the patients without urinary complications(7608cGy v 6960cGy, p<0.01). Maximum rectal dose for the group of patients with rectal complications was higher than that for the patients without urinary complications (7041cGy v 6269cGy, p<0.01). While there was no significant

  11. Stages of Penile Cancer

    Science.gov (United States)

    ... under a microscope . Stage II In stage II , cancer has spread: to connective tissue just under the skin of the penis . Also, ... spread to one lymph node in the groin . Cancer has also spread: to connective tissue just under the skin of the penis . Also, ...

  12. Geodynamo Modeling of Core-Mantle Interactions

    Science.gov (United States)

    Kuang, Wei-Jia; Chao, Benjamin F.; Smith, David E. (Technical Monitor)

    2001-01-01

    Angular momentum exchange between the Earth's mantle and core influences the Earth's rotation on time scales of decades and longer, in particular in the length of day (LOD) which have been measured with progressively increasing accuracy for the last two centuries. There are four possible coupling mechanisms for transferring the axial angular momentum across the core-mantle boundary (CMB): viscous, magnetic, topography, and gravitational torques. Here we use our scalable, modularized, fully dynamic geodynamo model for the core to assess the importance of these torques. This numerical model, as an extension of the Kuang-Bloxham model that has successfully simulated the generation of the Earth's magnetic field, is used to obtain numerical results in various physical conditions in terms of specific parameterization consistent with the dynamical processes in the fluid outer core. The results show that depending on the electrical conductivity of the lower mantle and the amplitude of the boundary topography at CMB, both magnetic and topographic couplings can contribute significantly to the angular momentum exchange. This implies that the core-mantle interactions are far more complex than has been assumed and that there is unlikely a single dominant coupling mechanism for the observed decadal LOD variation.

  13. Moho vs crust-mantle boundary: Evolution of an idea

    Science.gov (United States)

    O'Reilly, Suzanne Y.; Griffin, W. L.

    2013-12-01

    The concept that the Mohorovicic Discontinuity (Moho) does not necessarily coincide with the base of the continental crust as defined by rock-type compositions was introduced in the early 1980s. This had an important impact on understanding the nature of the crust-mantle boundary using information from seismology and from deep-seated samples brought to the surface as xenoliths in magmas, or as tectonic terranes. The use of empirically-constrained P-T estimates to plot the locus of temperature vs depth for xenoliths defined a variety of geotherms depending on tectonic environment. The xenolith geotherms provided a framework for constructing lithological sections through the deep lithosphere, and revealed that the crust-mantle boundary in off-craton regions commonly is transitional over a depth range of about 5-20 km. Early seismic-reflection data showed common layering near the Moho, correlating with the petrological observation of multiple episodes of basaltic intrusion around the crust-mantle boundary. Developments in seismology, petrophysics and experimental petrology have refined interpretation of lithospheric domains. The expansion of in situ geochronology (especially zircon U-Pb ages and Hf-isotopes; Os isotopes of mantle sulfides) has defined tectonic events that affected whole crust-mantle sections, and revealed that the crust-mantle boundary can change in depth through time. However, the nature of the crust-mantle boundary in cratonic regions remains enigmatic, mainly due to lack of key xenoliths or exposed sections. The observation that the Moho may lie significantly deeper than the crust-mantle boundary has important implications for modeling the volume of the crust. Mapping the crust using seismic techniques alone, without consideration of the petrological problems, may lead to an overestimation of crustal thickness by 15-30%. This will propagate to large uncertainties in the calculation of elemental mass balances relevant to crust-formation processes

  14. Clustering of arc volcanoes caused by temperature perturbations in the back-arc mantle.

    Science.gov (United States)

    Lee, Changyeol; Wada, Ikuko

    2017-06-29

    Clustering of arc volcanoes in subduction zones indicates along-arc variation in the physical condition of the underlying mantle where majority of arc magmas are generated. The sub-arc mantle is brought in from the back-arc largely by slab-driven mantle wedge flow. Dynamic processes in the back-arc, such as small-scale mantle convection, are likely to cause lateral variations in the back-arc mantle temperature. Here we use a simple three-dimensional numerical model to quantify the effects of back-arc temperature perturbations on the mantle wedge flow pattern and sub-arc mantle temperature. Our model calculations show that relatively small temperature perturbations in the back-arc result in vigorous inflow of hotter mantle and subdued inflow of colder mantle beneath the arc due to the temperature dependence of the mantle viscosity. This causes a three-dimensional mantle flow pattern that amplifies the along-arc variations in the sub-arc mantle temperature, providing a simple mechanism for volcano clustering.

  15. Restitic or not? Insights from trace element content and crystal - Structure of spinels in African mantle xenoliths

    Science.gov (United States)

    Lenaz, Davide; Musco, Maria Elena; Petrelli, Maurizio; Caldeira, Rita; De Min, Angelo; Marzoli, Andrea; Mata, Joao; Perugini, Diego; Princivalle, Francesco; Boumehdi, Moulay Ahmed; Bensaid, Idris Ali Ahmadi; Youbi, Nasrrddine

    2017-05-01

    The lithospheric architecture of Africa consists of several Archean cratons and smaller cratonic fragments, stitched together and flanked by polycyclic fold belts. Here we investigate the structure and chemistry of spinels from lithospheric mantle xenoliths from distinct tectonic settings, i.e. from the Saharan metacraton in Libya (Waw-En-Namus) which could show archaic chemical features, Cameroon (Barombi Koto and Nyos Lakes) where the Sub Continental Lithospheric Mantle was modified during the Pan-African event and fluxed by asthenospheric melts of the Tertiary Cameroon Volcanic Line and Morocco (Tafraoute, Bou-Ibalrhatene maars) in the Middle Atlas where different metasomatic events have been recorded. From a structural point of view it is to notice that the Libyan spinels can be divided into two groups having different oxygen positional parameter (u > 0.2632 and u Morocco spinels show a Tc in the range 630-760 °C. About 150 different spinels have been studied for their trace element content and it can be seen that many of them are related to Cr content, while Zn and Co are not and clearly distinguish the occurrences. Differences in the trace element chemistry, in the structural parameters and in the intracrystalline closure temperatures suggest that a different history should be considered for Cameroon, Morocco and LB I and LB II spinels. Even if it was not considered for this purpose, we tentatively used the Fe2 +/Fe3 + vs. TiO2 diagram that discriminate between peridotitic and the so-called "magmatic" spinels, i.e. spinel crystallized from melts. LB I and LB II spinels plot in the peridotitic field while Cameroon and Morocco spinels fall in the magmatic one. Consequently, the xenoliths sampled from a probably juvenile SCLM at the edge of the most important lithospheric roots (i.e. Cameroon and Morocco) apparently have spinels possibly fractionated in situ from percolating melts and do not represent a real spinel-peridotite facies. On the contrary mantle

  16. Rb-Sr mantle isochrons from oceanic regions

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, C; Hart, S R; Hofmann, A; James, D E [Carnegie Institution of Washington, D.C. (USA). Dept. of Terrestrial Magnetism

    1976-09-01

    Existing data for /sup 87/Sr//sup 86/Sr and Rb/Sr ratios of basalts from oceanic islands and mid-ocean spreading ridges show significant positive correlations on a Rb-Sr isochron diagram (when data are averaged by island group). Furthermore, tholeiites and alkali basalts occupy distinct non-overlapping fields on this plot. The tholeiite correlation is interpreted as a mantle isochron, and the agreement of this age (1.6+-0.2 b.y.) with that reported for Pb-Pb isochrons from oceanic basalts lends strong support to the use of such isochrons for tracing mantle evolution. Oceanic basalts are apparently sampling a mantle in which chemical heterogeneities have persisted for at least 1.5-2.0 b.y. The data support a kinematic model for the mantle in which a relatively uniform and non-radiogenic asthenosphere is penetrated by, and mixed with, blobs or plumes derived from an isolated (1.5-2 b.y.) and chemically heterogeneous mesosphere.

  17. Mantle helium in the Red Sea brines

    International Nuclear Information System (INIS)

    Lupton, J.E.; Weiss, R.F.; Craig, H.

    1977-01-01

    It is stated that He isotope studies of terrestrial samples have shown the existence of two He components that are clearly distinct from atmospheric He. These are termed 'crustal' He and 'mantle' He; the latter was discovered as 'excess 3 He' in deep ocean water and attributed to a flux of primordial He from the mantle. Studies of the 3 He/ 4 He ratio in deep Pacific water and in He trapped in submarine basalt glasses showed that this 'mantle' component is characterised by ratios about ten times the atmospheric ratio and 100 times the ratio in 'crustal' He. Basalt glasses from other deep sea waters also showed similar ratios, and it is indicated that 'mantle' He in areas in which new lithosphere is being formed has a unique and uniform isotopic signature. Measurements of He and Ne are here reported that reveal additional information on the origin of Red Sea brines and their relationship to the Red Sea rifts. (U.K.)

  18. Continental smokers couple mantle degassing and distinctive microbiology within continents

    Science.gov (United States)

    Crossey, Laura J.; Karlstrom, Karl E.; Schmandt, Brandon; Crow, Ryan R.; Colman, Daniel R.; Cron, Brandi; Takacs-Vesbach, Cristina D.; Dahm, Clifford N.; Northup, Diana E.; Hilton, David R.; Ricketts, Jason W.; Lowry, Anthony R.

    2016-02-01

    The discovery of oceanic black (and white) smokers revolutionized our understanding of mid-ocean ridges and led to the recognition of new organisms and ecosystems. Continental smokers, defined here to include a broad range of carbonic springs, hot springs, and fumaroles that vent mantle-derived fluids in continental settings, exhibit many of the same processes of heat and mass transfer and ecosystem niche differentiation. Helium isotope (3He/4He) analyses indicate that widespread mantle degassing is taking place in the western U.S.A., and that variations in mantle helium values correlate best with low seismic-velocity domains in the mantle and lateral contrasts in mantle velocity rather than crustal parameters such as GPS, proximity to volcanoes, crustal velocity, or composition. Microbial community analyses indicate that these springs can host novel microorganisms. A targeted analysis of four springs in New Mexico yield the first published occurrence of chemolithoautotrophic Zetaproteobacteria in a continental setting. These observations lead to two linked hypotheses: that mantle-derived volatiles transit through conduits in extending continental lithosphere preferentially above and at the edges of mantle low velocity domains. High CO2 and other constituents ultimately derived from mantle volatiles drive water-rock interactions and heterogeneous fluid mixing that help structure diverse and distinctive microbial communities.

  19. Tectonic predictions with mantle convection models

    Science.gov (United States)

    Coltice, Nicolas; Shephard, Grace E.

    2018-04-01

    Over the past 15 yr, numerical models of convection in Earth's mantle have made a leap forward: they can now produce self-consistent plate-like behaviour at the surface together with deep mantle circulation. These digital tools provide a new window into the intimate connections between plate tectonics and mantle dynamics, and can therefore be used for tectonic predictions, in principle. This contribution explores this assumption. First, initial conditions at 30, 20, 10 and 0 Ma are generated by driving a convective flow with imposed plate velocities at the surface. We then compute instantaneous mantle flows in response to the guessed temperature fields without imposing any boundary conditions. Plate boundaries self-consistently emerge at correct locations with respect to reconstructions, except for small plates close to subduction zones. As already observed for other types of instantaneous flow calculations, the structure of the top boundary layer and upper-mantle slab is the dominant character that leads to accurate predictions of surface velocities. Perturbations of the rheological parameters have little impact on the resulting surface velocities. We then compute fully dynamic model evolution from 30 and 10 to 0 Ma, without imposing plate boundaries or plate velocities. Contrary to instantaneous calculations, errors in kinematic predictions are substantial, although the plate layout and kinematics in several areas remain consistent with the expectations for the Earth. For these calculations, varying the rheological parameters makes a difference for plate boundary evolution. Also, identified errors in initial conditions contribute to first-order kinematic errors. This experiment shows that the tectonic predictions of dynamic models over 10 My are highly sensitive to uncertainties of rheological parameters and initial temperature field in comparison to instantaneous flow calculations. Indeed, the initial conditions and the rheological parameters can be good enough

  20. Thermally-Driven Mantle Plumes Reconcile Hot-spot Observations

    Science.gov (United States)

    Davies, D.; Davies, J.

    2008-12-01

    Hot-spots are anomalous regions of magmatism that cannot be directly associated with plate tectonic processes (e.g. Morgan, 1972). They are widely regarded as the surface expression of upwelling mantle plumes. Hot-spots exhibit variable life-spans, magmatic productivity and fixity (e.g. Ito and van Keken, 2007). This suggests that a wide-range of upwelling structures coexist within Earth's mantle, a view supported by geochemical and seismic evidence, but, thus far, not reproduced by numerical models. Here, results from a new, global, 3-D spherical, mantle convection model are presented, which better reconcile hot-spot observations, the key modification from previous models being increased convective vigor. Model upwellings show broad-ranging dynamics; some drift slowly, while others are more mobile, displaying variable life-spans, intensities and migration velocities. Such behavior is consistent with hot-spot observations, indicating that the mantle must be simulated at the correct vigor and in the appropriate geometry to reproduce Earth-like dynamics. Thermally-driven mantle plumes can explain the principal features of hot-spot volcanism on Earth.

  1. Differences in clinical presentation between bipolar I and II disorders in the early stages of bipolar disorder

    DEFF Research Database (Denmark)

    Vinberg, Maj; Mikkelsen, Rie Lambaek; Kirkegaard, Thomas

    2017-01-01

    Aim In a naturalistic clinical study of patients in the early stages of bipolar disorders the aim was to assess differences between patients with bipolar I (BD I) and bipolar II (BD II) disorders on clinical characteristics including affective symptoms, subjective cognitive complaints, functional...... level, the presence of comorbid personality disorders and coping strategies. Methods Diagnoses were confirmed using the Structured Clinical Interview for DSM-IV Disorders. Clinical symptoms were rated with the Young Mania Rating Scale and the Hamilton Depression Rating Scale, and functional status using...... Inventory for Stressful Situations. Results In total, 344 patients were included (BD I (n=163) and BD II (n=181). Patients with BD II presented with significantly more depressive symptoms, more cognitive complaints, lower overall functioning, and a higher prevalence of comorbid personality disorders...

  2. Mineralogy of the Hydrous Lower Mantle

    Science.gov (United States)

    Shim, S. H.; Chen, H.; Leinenweber, K. D.; Kunz, M.; Prakapenka, V.; Bechtel, H.; Liu, Z.

    2017-12-01

    The hydrous ringwoodite inclusions found in diamonds suggest water storage in the mantle transition zone. However, water storage in the lower mantle remains unclear. Bridgmanite and magnesiowustite appear to have very little storage capacity for water. Here, we report experimental results indicating significant changes in the lower-mantle mineralogy under the presence of water. We have synthesized Mg2SiO4 ringwoodite with 2 wt% water in multi-anvil press at 20 GPa and 1573 K at ASU. The hydrous ringwoodite sample was then loaded to diamond anvil cells with Ar or Ne as a pressure medium. We heated the pure hydrous ringwoodite samples at lower-mantle pressure using a CO2 laser heating system at ASU. We measured X-ray diffraction patterns at the GSECARS sector of the Advanced Photon Source (APS) and 12.2.2 sector of the Advanced Light Source (ALS). For the separate Pt-mixed samples, we have conducted in situ heating at the beamlines using near IR laser heating systems. We measured the infrared spectra of the heated samples at high pressure and after pressure quench at 1.4.4 sector of ALS. In the in situ experiments with hydrous ringwoodite + Pt mixture as a starting material, we found formation of stishovite together with bridgmanite and periclase during heating with a near IR laser beams at 1300-2500 K and 35-66 GPa. However, some hydrous ringwoodite still remains even after a total of 45 min of heating. In contrast, the hydrous ringwoodite samples heated without Pt by CO2 laser beams are transformed completely to bridgmanite, periclase and stishovite at 31-55 GPa and 1600-1900 K. We have detected IR active OH mode of stishovite from the samples heated at lower-mantle pressures. The unit-cell volume of stishovite measured after pressure quench is greater than that of dry stishovite by 0.3-0.6%, supporting 0.5-1 wt% of H2O in stishovite in these samples. Stishovite is a thermodynamically forbidden phase in the dry lower mantle because of the existence of periclase and

  3. Profiling MHC II immunopeptidome of blood-stage malaria reveals that cDC1 control the functionality of parasite-specific CD4 T cells.

    Science.gov (United States)

    Draheim, Marion; Wlodarczyk, Myriam F; Crozat, Karine; Saliou, Jean-Michel; Alayi, Tchilabalo Dilezitoko; Tomavo, Stanislas; Hassan, Ali; Salvioni, Anna; Demarta-Gatsi, Claudia; Sidney, John; Sette, Alessandro; Dalod, Marc; Berry, Antoine; Silvie, Olivier; Blanchard, Nicolas

    2017-11-01

    In malaria, CD4 Th1 and T follicular helper (T FH ) cells are important for controlling parasite growth, but Th1 cells also contribute to immunopathology. Moreover, various regulatory CD4 T-cell subsets are critical to hamper pathology. Yet the antigen-presenting cells controlling Th functionality, as well as the antigens recognized by CD4 T cells, are largely unknown. Here, we characterize the MHC II immunopeptidome presented by DC during blood-stage malaria in mice. We establish the immunodominance hierarchy of 14 MHC II ligands derived from conserved parasite proteins. Immunodominance is shaped differently whether blood stage is preceded or not by liver stage, but the same ETRAMP-specific dominant response develops in both contexts. In naïve mice and at the onset of cerebral malaria, CD8α + dendritic cells (cDC1) are superior to other DC subsets for MHC II presentation of the ETRAMP epitope. Using in vivo depletion of cDC1, we show that cDC1 promote parasite-specific Th1 cells and inhibit the development of IL-10 + CD4 T cells. This work profiles the P. berghei blood-stage MHC II immunopeptidome, highlights the potency of cDC1 to present malaria antigens on MHC II, and reveals a major role for cDC1 in regulating malaria-specific CD4 T-cell responses. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  4. 5-YEAR SURVIVAL OF PATIENTS WITH STAGE II UTERINE CANCER DEPENDING ON MORPHOLOGIC FEATURES OF TUMOR

    Directory of Open Access Journals (Sweden)

    Ye. A. Mustafina

    2008-01-01

    Full Text Available Retrospective data of treatment results of 109 patients with rarely observed stage II uterine cancer, admitted to N.N. Blokhin Russian Cancer Research Center from 1980 to 2000 is analyzed. Correlation of overall 5-year survival rates of stage IIA and IIB uterine can- cer patients with a number of tumor morphologic features is studied. The influence of some non-elucidated morphologic features of stage IIA and IIB uterine cancer such as the degree of cellular anaplasia, the depth of tumor invasion into the uterine neck, lymho- vascular invasion into the myometrium and uterine neck, microscopic vessels density in the area of the most extensive invasion, the presence of necrotic areas in the tumor tissue on long-term treatment results are analyzed.

  5. Tiotropium bromide in the routine care of GOLD stage II COPD patients: a pharmaeconomic evaluation

    Directory of Open Access Journals (Sweden)

    Orietta Zaniolo

    2011-06-01

    Full Text Available Background: a secondary pre-specified analysis of the UPLIFT cohort demonstrated that the inclusion of tiotropium bromide in the routine care of GOLD stage II (moderate chronic obstructive pulmonary disease (COPD patients is associated with stronger improvements of survival, quality of life, and exacerbation rate than those shown in the total cohort; in this subgroup, tiotropium furthermore induces a significant reduction in the rate of FEV1 decline.Objective: to adapt the Spiriva® model, originally built to evaluate cost-effectiveness of tiotropium inclusion in the general COPD population, to GOLD II patients.Methods: the Spiriva® model is a probabilistic Markov patient-level simulation developed over a lifetime horizon to compare outcomes associated with the inclusion of tiotropium in routine care (RC for COPD treatment with those obtained with RC alone. Patients are characterised by gender, age, height, smoking status and FEV1. Model structure and sources have been maintained unvaried, except for demographic characteristics, specific for GOLD II patients, as extrapolated from an Italian observational study, and tiotropium efficacy, based on the secondary analysis of GOLD II UPLIFT patients. As in the original model, only direct health care costs are considered.Results: patients treated with tiotropium on average (95% CI gain 0.70 (0.00/7.23 LYs or 0.77 (0.02/4.67 QALYs compared to RC. The incremental lifetime cost is € 3,520 (-6,391/26,686, meaning that the incremental cost required to gain a QALY (incremental cost-effectiveness ratio – ICER is equal to € 4,548. Sensitivity analysis shows that tiotropium has a 50% probability of being cost-effective for a willingness-to-pay (WTP around 4,600 €/QALY; 100% probability is achieved with a WTP of € 9,300.Conclusions: the adoption of a strategy based on the inclusion of tiotropium from the early COPD stages represents good value for money in Italy, as the ICER estimated for GOLD II

  6. Dynamical links between small- and large-scale mantle heterogeneity: Seismological evidence

    Science.gov (United States)

    Frost, Daniel A.; Garnero, Edward J.; Rost, Sebastian

    2018-01-01

    We identify PKP • PKP scattered waves (also known as P‧ •P‧) from earthquakes recorded at small-aperture seismic arrays at distances less than 65°. P‧ •P‧ energy travels as a PKP wave through the core, up into the mantle, then scatters back down through the core to the receiver as a second PKP. P‧ •P‧ waves are unique in that they allow scattering heterogeneities throughout the mantle to be imaged. We use array-processing methods to amplify low amplitude, coherent scattered energy signals and resolve their incoming direction. We deterministically map scattering heterogeneity locations from the core-mantle boundary to the surface. We use an extensive dataset with sensitivity to a large volume of the mantle and a location method allowing us to resolve and map more heterogeneities than have previously been possible, representing a significant increase in our understanding of small-scale structure within the mantle. Our results demonstrate that the distribution of scattering heterogeneities varies both radially and laterally. Scattering is most abundant in the uppermost and lowermost mantle, and a minimum in the mid-mantle, resembling the radial distribution of tomographically derived whole-mantle velocity heterogeneity. We investigate the spatial correlation of scattering heterogeneities with large-scale tomographic velocities, lateral velocity gradients, the locations of deep-seated hotspots and subducted slabs. In the lowermost 1500 km of the mantle, small-scale heterogeneities correlate with regions of low seismic velocity, high lateral seismic gradient, and proximity to hotspots. In the upper 1000 km of the mantle there is no significant correlation between scattering heterogeneity location and subducted slabs. Between 600 and 900 km depth, scattering heterogeneities are more common in the regions most remote from slabs, and close to hotspots. Scattering heterogeneities show an affinity for regions close to slabs within the upper 200 km of the

  7. Flow in the Deep Mantle from Seisimc Anisotropy: Progress and Prospects

    Science.gov (United States)

    Long, M. D.

    2017-12-01

    Observations of seismic anisotropy, or the directional dependence of seismic wavespeeds, provide one some of the most direct constraints on the pattern of flow in the Earth's mantle. In particular, as our understanding of crystallographic preferred orientation (CPO) of olivine aggregates under a range of deformation conditions has improved, our ability to exploit observations of upper mantle anisotropy has led to fundamental discoveries about the patterns of flow in the upper mantle and the drivers of that flow. It has been a challenge, however, to develop a similar framework for understanding flow in the deep mantle (transition zone, uppermost lower mantle, and lowermost mantle), even though there is convincing observational evidence for seismic anisotropy at these depths. Recent progress on the observational front has allowed for an increasingly detailed view of mid-mantle anisotropy (transition zone and uppermost lower mantle), particularly in subduction systems, which may eventually lead to a better understanding of mid-mantle deformation and the dynamics of slab interaction with the surrounding mid-mantle. New approaches to the observation and modeling of lowermost mantle anisotropy, in combination with constraints from mineral physics, are progressing towards interpretive frameworks that allow for the discrimination of different mantle flow geometries in different regions of D". In particular, observational strategies that involve the use of multiple types of body wave phases sampled over a range of propagation azimuths enable detailed forward modeling approaches that can discriminate between different mechanisms for D" anisotropy (e.g., CPO of post-perovskite, bridgmanite, or ferropericlase, or shape preferred orientation of partial melt) and identify plausible anisotropic orientations. We have recently begun to move towards a full waveform modeling approach in this work, which allows for a more accurate simulation for seismic wave propagation. Ongoing

  8. Efficacy of biofeedback on quality of life in stages I and II pelvic organ prolapse: A Pilot study.

    Science.gov (United States)

    Ahadi, Tannaz; Taghvadoost, Neda; Aminimoghaddam, Soheila; Forogh, Bijan; Bazazbehbahani, Roxana; Raissi, Gholam Reza

    2017-08-01

    Pelvic organ prolapse (POP) is a prevalent disorder which seriously affects the sufferer's quality of life. The main goal of this study was to evaluate biofeedback impact on quality of life in women with mild to moderate POP. 40 females in stages I and II POP were allocated into 2 groups. One group received pelvic floor muscle exercise and lifestyle advice in addition to biofeedback twice a week for 4 weeks, while the other received a lifestyle advice sheet and pelvic floor muscle exercise without biofeedback. A valid Persian version of P-QOL questionnaire was applied to assess the patients̕ quality of life at baseline, 4 weeks and 12 weeks follow up. Pressure biofeedback and Physical examination were also performed in order to determine pelvic floor muscle strength and staging of the prolapse, respectively. Collected data were analyzed by mixed ANOVA test using SPSS 22. Biofeedback improved the quality of life in seven of nine P-QOL domains. However, it had no significant impact either on pelvic floor muscle strength or on the stage of the prolapse. Biofeedback could be considered as a non-invasive treatment leading to quality of life promotion in women with stages I and II POP. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Core-Mantle Partitioning of Volatile Elements and the Origin of Volatile Elements in Earth and Moon

    Science.gov (United States)

    Righter, K.; Pando, K.; Danielson, L.; Nickodem, K.

    2014-01-01

    Depletions of siderophile elements in mantles have placed constraints on the conditions on core segregation and differentiation in bodies such as Earth, Earth's Moon, Mars, and asteroid 4 Vesta. Among the siderophile elements there are a sub-set that are also volatile (volatile siderophile elements or VSE; Ga, Ge, In, As, Sb, Sn, Bi, Zn, Cu, Cd), and thus can help to constrain the origin of volatile elements in these bodies, and in particular the Earth and Moon. One of the fundamental observations of the geochemistry of the Moon is the overall depletion of volatile elements relative to the Earth, but a satisfactory explanation has remained elusive. Hypotheses for Earth include addition during accretion and core formation and mobilized into the metallic core, multiple stage origin, or addition after the core formed. Any explanation for volatile elements in the Earth's mantle must also be linked to an explanation of these elements in the lunar mantle. New metal-silicate partitioning data will be applied to the origin of volatile elements in both the Earth and Moon, and will evaluate theories for exogenous versus endogenous origin of volatile elements.

  10. Quantifying mantle structure and dynamics using plume tracing in seismic tomography

    Science.gov (United States)

    O'Farrell, K. A.; Eakin, C. M.; Jackson, M. G.; Jones, T. D.; Lekic, V.; Lithgow-Bertelloni, C. R.

    2017-12-01

    Directly linking deep mantle processes with surface features and dynamics is a complex problem. Hotspot volcanism gives us surface observables of mantle signatures, but the depth and source of the mantle plumes feeding these hotspots are highly debated. To address these issues, it is necessary to consider the entire journey of a plume through the mantle. By analyzing the behavior of mantle plumes we can constrain the vigor of mantle convection, the net rotation of the mantle and the role of thermal versus chemical anomalies as well as the bulk physical properties such as the viscosity profile. To do this, we developed a new algorithm to trace plume-like features in shear-wave (Vs) seismic tomography models based on picking local minima in the velocity and searching for continuous features with depth. We applied this method to recent tomographic models and find 60+ continuous plume conduits that are > 750 km long. Approximately a third of these can be associated with known hotspots at the surface. We analyze the morphology of these continuous conduits and infer large scale mantle flow patterns and properties. We find the largest lateral deflections in the conduits occur near the base of the lower mantle and in the upper mantle (near the thermal boundary layers). The preferred orientation of the plume deflections show large variability at all depths and indicate no net mantle rotation. Plate by plate analysis shows little agreement in deflection below particular plates, indicating these deflected features might be long lived and not caused by plate shearing. Changes in the gradient of plume deflection are inferred to correspond with viscosity contrasts in the mantle and found below the transition zone as well as at 1000 km depth. From this inferred viscosity structure, we explore the dynamics of a plume through these viscosity jumps. We also retrieve the Vs profiles for the conduits and compare with the velocity profiles predicted for different mantle adiabat

  11. Radiological safety assessment of gas mantle industries in India

    International Nuclear Information System (INIS)

    Sadagopan, G.; Venkataraman, G.

    1994-01-01

    Thorium, a radioactive element of actinide family was discovered by Berzelius in 1828 and named by him in honor of the Scandinavian God open-quote Thor close-quote. Following its discovery the earliest known use of thorium was in the making of gas mantles. The other use as an X-ray contrast medium open-quote Thorotrast close-quote has since long been discontinued, where as even today its use in gas mantles is continued. Gas lights have been used as a source of light since 1800's. In India, although electric bulbs have replaced most of the gas lights, even today in villages and in urban areas where there is no continuous power supply and in outdoor lightings gas lamps are used. The mantle which is used in these lamps is called the Welsbach mantle and is a netted hose that is impregnated with thorium nitrate and other metals. The function of a gas mantle is to produce a bright light during operation of the lighting device (gas or kerosene lamp) in which the mantle is placed. When placed in a lighting device and heated to 1300-1800 degree Celcius thorium in the mantle incandesces and gives off bright light. In India presently there are about 70 manufacturing units handling 150 metric tons of thorium nitrate annually. There are about four hundred persons involved in manufacturing 200 million mantles per year. Thorium is chosen because of its property of incadescence, however since it is radioactive, radiation safety of the workplace, handling personnel and safe environmental condition for members of public have to be maintained

  12. Cluster II quartet take the stage together

    Science.gov (United States)

    1999-11-01

    This is the only occasion on which all four of ESA's Cluster II spacecraft will be on display together in Europe. Four Spacecraft, One Mission The unique event takes place near the end of the lengthy assembly and test programme, during which each individual spacecraft is being assembled in sequence, one after the other. Two have already completed their assembly and systems testing and are about to be stored in special containers at IABG prior to shipment to the Baikonur launch site in Kazakhstan next spring. In the case of the other two, flight models 5 and 8, installation of the science payloads has finished, but their exhaustive series of environmental tests at IABG have yet to begin. Following delivery to the launch site next April, the satellites will be launched in pairs in June and July 2000. Two Soyuz rockets, each with a newly designed Fregat upper stage, are being provided by the Russian-French Starsem company. This will be the first time ESA satellites have been launched from the former Soviet Union. Cluster II is a replacement for the original Cluster mission, which was lost during the maiden launch of Ariane 5 in June 1996. ESA, given the mission's importance in its overall strategy in the area of the Sun-Earth connection, decided to rebuild this unique project. ESA member states supported that proposal. On 3 April 1997, the Agency's Science Programme Committee agreed. Cluster II was born. European Teamwork Scientific institutions and industrial enterprises in almost all the 14 ESA member states and the United States are taking part in the Cluster II project. Construction of the eight Cluster / Cluster II spacecraft has been a major undertaking for European industry. Built into each 1200 kg satellite are six propellant tanks, two pressure tanks, eight thrusters, 80 metres of pipework, about 5 km of wiring, 380 connectors and more than 14 000 electrical contacts. All the spacecraft were assembled in the giant clean room at the Friedrichshafen plant of

  13. Executive Summary: “Mantle Frontier” Workshop

    Directory of Open Access Journals (Sweden)

    Workshop Report Writing Group

    2011-03-01

    Full Text Available The workshop on “Reaching the Mantle Frontier: Moho and Beyond” was held at the Broad Branch Road Campus of the Carnegie Institution of Washington on 9–11 September 2010. The workshop attracted seventy-four scientists and engineers from academia and industry in North America, Asia, and Europe.Reaching and sampling the mantle through penetration of the entire oceanic crust and the Mohorovičić discontinuity (Moho has been a longstanding goal of the Earth science community. The Moho is a seismic transition, often sharp, from a region with compressional wave velocities (Vp less than 7.5 km s-1 to velocities ~8 km s-1. It is interpreted in many tectonic settings, and particularly in tectonic exposures of oceanic lower crust, as the transition from igneous crust to mantle rocks that are the residues of melt extraction. Revealing the in situ geological meaning of the Moho is the heart of the Mohole project. Documenting ocean-crust exchanges and the nature and extent of the subseafloor biosphere have also become integral components of the endeavor. The purpose of the “Mantle Frontier” workshop was to identify key scientific objectives associated with innovative technology solutions along with associated timelines and costs for developments and implementation of this grandchallenge.

  14. Reconciling laboratory and observational models of mantle rheology in geodynamic modelling

    Science.gov (United States)

    King, Scott D.

    2016-10-01

    Experimental and geophysical observations constraining mantle rheology are reviewed with an emphasis on their impact on mantle geodynamic modelling. For olivine, the most studied and best-constrained mantle mineral, the tradeoffs associated with the uncertainties in the activation energy, activation volume, grain-size and water content allow the construction of upper mantle rheology models ranging from nearly uniform with depth to linearly increasing from the base of the lithosphere to the top of the transition zone. Radial rheology models derived from geophysical observations allow for either a weak upper mantle or a weak transition zone. Experimental constraints show that wadsleyite and ringwoodite are stronger than olivine at the top of the transition zone; however the uncertainty in the concentration of water in the transition zone precludes ruling out a weak transition zone. Both observational and experimental constraints allow for strong or weak slabs and the most promising constraints on slab rheology may come from comparing inferred slab geometry from seismic tomography with systematic studies of slab morphology from dynamic models. Experimental constraints on perovskite and ferropericlase strength are consistent with general feature of rheology models derived from geophysical observations and suggest that the increase in viscosity through the top of the upper mantle could be due to the increase in the strength of ferropericlase from 20-65 GPa. The decrease in viscosity in the bottom half of the lower mantle could be the result of approaching the melting temperature of perovskite. Both lines of research are consistent with a high-viscosity lithosphere, a low viscosity either in the upper mantle or transition zone, and high viscosity in the lower mantle, increasing through the upper half of the lower mantle and decreasing in the bottom half of the lower mantle, with a low viscosity above the core. Significant regions of the mantle, including high

  15. Lithospheric mantle evolution in the Afro-Arabian domain: Insights from Bir Ali mantle xenoliths (Yemen)

    Science.gov (United States)

    Sgualdo, P.; Aviado, K.; Beccaluva, L.; Bianchini, G.; Blichert-Toft, J.; Bryce, J. G.; Graham, D. W.; Natali, C.; Siena, F.

    2015-05-01

    Detailed petrological and geochemical investigations of an extensive sampling of mantle xenoliths from the Neogene-Quaternary Bir Ali diatreme (southern Yemen) indicate that the underlying lithospheric mantle consists predominantly of medium- to fine-grained (often foliated) spinel-peridotites (85-90%) and spinel-pyroxenites (10-15%) showing thermobarometric estimates in the P-T range of 0.9-2.0 GPa and 900-1150 °C. Peridotites, including lherzolites, harzburgites and dunites delineate continuous chemical, modal and mineralogical variations compatible with large extractions of basic melts occurring since the late Proterozoic (~ 2 Ga, according to Lu-Hf model ages). Pyroxenites may represent intrusions of subalkaline basic melts interacting and equilibrated with the host peridotite. Subsequent metasomatism has led to modal changes, with evidence of reaction patches and clinopyroxene and spinel destabilization, as well as formation of new phases (glass, amphibole and feldspar). These changes are accompanied by enrichment of the most incompatible elements and isotopic compositions. 143Nd/144Nd ranges from 0.51419 to 0.51209 (εNd from + 30.3 to - 10.5), 176Hf/177Hf from 0.28459 to 0.28239 (εHf from + 64.4 to - 13.6), and 208Pb/204Pb from 36.85 to 41.56, thus extending from the depleted mantle (DM) towards the enriched OIB mantle (EM and HIMU) components. 3He/4He (R/RA) ratios vary from 7.2 to 7.9 with He concentrations co-varying with the most incompatible element enrichment, in parallel with metasomatic effects. These metasomatic events, particularly effective in harzburgites and dunites, are attributable to the variable interaction with alkaline basic melts related to the general extensional and rifting regime affecting the East Africa-Arabian domain during the Cenozoic. In this respect, Bir Ali mantle xenoliths resemble those occurring along the Arabian margins and the East Africa Rift system, similarly affected by alkaline metasomatism, whereas they are

  16. The Outcome of Postoperative Radiation Therapy for Patients with Stage II Pancreatic Cancer (T3 or N1 Disease)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Won; Chun, Misun; Kim, Myung Wook; Kim, Wook Hwan; Kang, Seok Yun; Kang, Seung Hee; Oh, Young Taek; Lee, Sunyoung; Yang, Juno [Ajou University School of Medicine, Suwon (Korea, Republic of)

    2007-12-15

    Purpose: To analyze retrospectively the outcome of postoperative radiation therapy with or without concurrent chemotherapy for curatively resected stage II pancreatic cancer with T3 or N1 disease. Materials and Methods: Between January 1996 and December 2005, twenty-eight patients completed adjuvant radiation therapy at Ajou University Hospital. The patients had either pathologic T3 stage or N1 stage. The radiation target volume encompassed the initial tumor bed identified preoperatively, resection margin area and celiac nodal area. In the case of N1 patients, the radiation field extended to the lower margin of the L3 vertebra for covering both para-aortic lymph nodes bearing area. The median total radiation dose was 50 Gy. Ten patients received concurrent chemotherapy. Results: Thirteen patients (46%) showed loco-regional recurrences. The celiac axis nodal area was the most frequent site (4 patients). Five patients showed both loco-regional recurrence and a distant metastasis. Patients with positive lymph nodes had a relatively high probability of a distant metastasis (57.1%). Patients that had a positive resection margin showed a relatively high local failure rate (57.1%). The median disease-free survival period of all patients was 6 months and the 1- and 2-year disease free survival rates were 27.4% and 8.2%, respectively. The median overall survival period was 9 months. The 2- and 3-year overall survival rates were 31.6% and 15.8%, respectively. Conclusion: The pancreatic cancer patients with stage II had a high risk of local failure and a high risk of a distant metastasis. We suggest the concurrent use of an effective radiation-sensitizing chemotherapeutic drug and adjuvant chemotherapy after postoperative radiation therapy for the treatment of patients with stage II pancreatic cancer.

  17. The Outcome of Postoperative Radiation Therapy for Patients with Stage II Pancreatic Cancer (T3 or N1 Disease)

    International Nuclear Information System (INIS)

    Kim, Sang Won; Chun, Misun; Kim, Myung Wook; Kim, Wook Hwan; Kang, Seok Yun; Kang, Seung Hee; Oh, Young Taek; Lee, Sunyoung; Yang, Juno

    2007-01-01

    Purpose: To analyze retrospectively the outcome of postoperative radiation therapy with or without concurrent chemotherapy for curatively resected stage II pancreatic cancer with T3 or N1 disease. Materials and Methods: Between January 1996 and December 2005, twenty-eight patients completed adjuvant radiation therapy at Ajou University Hospital. The patients had either pathologic T3 stage or N1 stage. The radiation target volume encompassed the initial tumor bed identified preoperatively, resection margin area and celiac nodal area. In the case of N1 patients, the radiation field extended to the lower margin of the L3 vertebra for covering both para-aortic lymph nodes bearing area. The median total radiation dose was 50 Gy. Ten patients received concurrent chemotherapy. Results: Thirteen patients (46%) showed loco-regional recurrences. The celiac axis nodal area was the most frequent site (4 patients). Five patients showed both loco-regional recurrence and a distant metastasis. Patients with positive lymph nodes had a relatively high probability of a distant metastasis (57.1%). Patients that had a positive resection margin showed a relatively high local failure rate (57.1%). The median disease-free survival period of all patients was 6 months and the 1- and 2-year disease free survival rates were 27.4% and 8.2%, respectively. The median overall survival period was 9 months. The 2- and 3-year overall survival rates were 31.6% and 15.8%, respectively. Conclusion: The pancreatic cancer patients with stage II had a high risk of local failure and a high risk of a distant metastasis. We suggest the concurrent use of an effective radiation-sensitizing chemotherapeutic drug and adjuvant chemotherapy after postoperative radiation therapy for the treatment of patients with stage II pancreatic cancer

  18. Beyond low-level activity: On a 'non-radioactive' gas mantle

    International Nuclear Information System (INIS)

    Poljanc, Karin; Steinhauser, Georg; Sterba, Johannes H.; Buchtela, Karl; Bichler, Max

    2007-01-01

    Gas mantles for camping gas lanterns sometimes contain thorium compounds. During the last years, the use of thorium-free gas mantles has become more and more popular due to the avoidance of a radioactive heavy metal. We investigated a gas mantle type that is declared to be 'non-radioactive' and that can be bought in Austria at the moment. Methods used were Instrumental Neutron Activation Analysis (INAA), γ-spectroscopy, and Liquid Scintillation Counting (LSC). We found massive thorium contents of up to 259 mg per gas mantle. Leaching experiments showed that only 0.4% of the Th but approximately 90% of the decay products of 232 Th can be leached under conditions simulating sucking and chewing with human saliva. In this paper, the investigation of these gas mantles including the consideration of the environmental hazard caused by disposed mantles and the health hazard for unsuspecting consumers is presented and legal consequences are discussed for this fraud

  19. The drama of the continuous increase in end-stage renal failure in patients with type II diabetes mellitus.

    Science.gov (United States)

    Rychlík, I; Miltenberger-Miltenyi, G; Ritz, E

    1998-01-01

    Type II diabetes mellitus has become the leading cause of end-stage renal failure in many countries of Western Europe. In all European countries, even in those with a relatively low prevalence of diabetic nephropathy, the number of patients with type II diabetes mellitus admitted for renal replacement therapy has recently increased continuously. Survival and medical rehabilitation of patients with type II diabetes on renal replacement therapy is significantly worse than in non-diabetic patients. It is obvious that in order to stem the tide, intense efforts are necessary (i) to inform the medical community about the renal risk of type II diabetes and the striking effectiveness of preventive measures, (ii) to provide better care for diabetic patients, and (iii) to reduce the high prevalence of diabetes in the population by modification of the Western life style.

  20. Plagioclase-mantled K-feldspar in the Carboniferous porphyritic microgranite of Altenberg-Frauenstein, Eastern Erzgebirge/Krusné Hory

    Directory of Open Access Journals (Sweden)

    Axel Müller

    2002-01-01

    Full Text Available The Upper Carboniferous porphyritic microgranite of Altenberg-Frauenstein, formerly known as Granitporphyr (Dalmer 1896 and here abbreviated as GP, forms a 36 km long and up to 18 km wide complex of ring dykes related to the Teplice-Altenberg caldera in the German–Czech border region of the Eastern Erzgebirge/Krusné Hory. The microgranites are characterized by the occurrence of plagioclase-mantled K-feldspar phenocrysts. The microgranite varieties representtwo main stages of intrusion evolved from acid (GP I to intermediaterocks (GP II within the intrusion. The most acid rock (GP Icum occurs as enclaves in GP I and GP II and is interpreted as a cumulate of K-feldspar and quartz phenocrysts. The porphyritic microgranites show field, textural and geochemical evidence suggesting that some of them have formed as a result of interaction between felsic and mafic magmas. Mixing features are abundant in the porphyriticquartz-feldspar-hornblende microgranite (GP II interpreted as a hybrid rock. They are less discrete in the early phase (GP I and not obvious in the acid enclaves (GP Icum. This trend seems to reflect a continuous deflation of the magma chamber from the top to the bottom. According to the definition of rapakivi granites after Haapala and Rämö (1992, the porphyritic microgranite of Altenberg-Frauenstein may be considered as rapakivi granite although ovoid alkali feldspar megacrysts typical of classical rapakivi granites are not recorded.However, due to its Carboniferous age and being the only known granitewith rapakivi texture in the German–Czech part of the Variscan belt, the microgranite of Altenberg-Frauenstein is exceptional.

  1. Intraplate mantle oxidation by volatile-rich silicic magmas

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Audrey M.; Médard, Etienne; Righter, Kevin; Lanzirotti, Antonio

    2017-11-01

    The upper subcontinental lithospheric mantle below the French Massif Central is more oxidized than the average continental lithosphere, although the origin of this anomaly remains unknown. Using iron oxidation analysis in clinopyroxene, oxybarometry, and melt inclusions in mantle xenoliths, we show that widespread infiltration of volatile (HCSO)-rich silicic melts played a major role in this oxidation. We propose the first comprehensive model of magmatism and mantle oxidation at an intraplate setting. Two oxidizing events occurred: (1) a 365–286 Ma old magmatic episode that produced alkaline vaugnerites, potassic lamprophyres, and K-rich calc-alkaline granitoids, related to the N–S Rhenohercynian subduction, and (2) < 30 Ma old magmatism related to W–E extension, producing carbonatites and hydrous potassic trachytes. These melts were capable of locally increasing the subcontinental lithospheric mantle fO2 to FMQ + 2.4. Both events originate from the melting of a metasomatized lithosphere containing carbonate + phlogopite ± amphibole. The persistence of this volatile-rich lithospheric source implies the potential for new episodes of volatile-rich magmatism. Similarities with worldwide magmatism also show that the importance of volatiles and the oxidation of the mantle in intraplate regions is underestimated.

  2. Water in geodynamical models of mantle convection and plate tectonics

    Science.gov (United States)

    Rodríguez-González, J.; Van Hunen, J.; Chotalia, K.; Lithgow-Bertelloni, C. R.; Rozel, A.; Tackley, P. J.; Nakagawa, T.

    2017-12-01

    The presence of water in the the mantle has a significant effect in the dynamical and thermal evolution of Earth, which partially explains the differences with other planets and is a key factor for the presence of life on Earth. First, a small amount of water can decrease the mantle viscosity by a several orders of magnitude, thereby changing the convection regime and affecting the thermal evolution. Second, the presence of water significantly changes the solidus curve, with crucial implications for melting. Third, water in the mantle can change the Clapeyron slope of mantle materials, which changes the depth at which phase transitions take place. The thermal and dynamical evolution of Earth under the presence of water in the mantle has been the focus of recent studies, but many questions remain unanswered. In this project we intend to investigate how the maximum water capacity of different mantle regions affects water transport and Earth's convective regime. We will study the effect phase transitions under the presence of water, which can change the buoyancy of slabs in the transition zone. We present preliminary results numerical models of global mantle convection for the whole history of earth using the numerical geodynamics software tool StagYY. We will use a new parametrisation of dehydration processes, obtained from high-resolution numerical simulations, to implement a more accurate description of the water released from the slab as it travels through the mantle. We have integrated recent experimental results of the water capacity of deep mantle minerals to study the water circulation and the total water budget. We use data from the most recent experiments and ab-inito calculations to implement a realistic rheology.

  3. Solar combi system based on a mantle tank

    DEFF Research Database (Denmark)

    Yazdanshenas, Eshagh; Furbo, Simon

    2007-01-01

    A solar combisystem based on a mantle tank is investigated numerically and experimentally. Three different houses with four different radiator systems are considered for the simulations. The needed temperature for the auxiliary heater is determined for different houses and radiator systems....... The thermal performance of the solar combisystem is compared to the thermal performance of a solar domestic hot water system based on a mantle tank. In the experimental study, tank temperatures and the heat transfer coefficient for the top mantle for a discharge test is determined. The investigations showed...

  4. Mantle temperature under drifting deformable continents during the supercontinent cycle

    Science.gov (United States)

    Yoshida, Masaki

    2013-04-01

    The thermal heterogeneity of the Earth's mantle under the drifting continents during a supercontinent cycle is a controversial issue in earth science. Here, a series of numerical simulations of mantle convection are performed in 3D spherical-shell geometry, incorporating drifting deformable continents and self-consistent plate tectonics, to evaluate the subcontinental mantle temperature during a supercontinent cycle. Results show that the laterally averaged temperature anomaly of the subcontinental mantle remains within several tens of degrees (±50 °C) throughout the simulation time. Even after the formation of the supercontinent and the development of subcontinental plumes due to the subduction of the oceanic plates, the laterally averaged temperature anomaly of the deep mantle under the continent is within +10 °C. This implies that there is no substantial temperature difference between the subcontinental and suboceanic mantles during a supercontinent cycle. The temperature anomaly immediately beneath the supercontinent is generally positive owing to the thermal insulation effect and the active upwelling plumes from the core-mantle boundary. In the present simulation, the formation of a supercontinent causes the laterally averaged subcontinental temperature to increase by a maximum of 50 °C, which would produce sufficient tensional force to break up the supercontinent. The periodic assembly and dispersal of continental fragments, referred to as the supercontinent cycle, bear close relation to the evolution of mantle convection and plate tectonics. Supercontinent formation involves complex processes of introversion, extroversion or a combination of these in uniting dispersed continental fragments, as against the simple opening and closing of individual oceans envisaged in Wilson cycle. In the present study, I evaluate supercontinent processes in a realistic mantle convection regime. Results show that the assembly of supercontinents is accompanied by a

  5. Tracking the Martian Mantle Signature in Olivine-Hosted Melt Inclusions of Basaltic Shergottites Yamato 980459 and Tissint

    Science.gov (United States)

    Peters, T. J.; Simon, J. I.; Jones, J. H.; Usui, T.; Moriwaki, R.; Economos, R.; Schmitt, A.; McKeegan, K.

    2014-01-01

    The Martian shergottite meteorites are basaltic to lherzolitic igneous rocks that represent a period of relatively young mantle melting and volcanism, approximately 600-150 Ma (e.g. [1,2]). Their isotopic and elemental composition has provided important constraints on the accretion, evolution, structure and bulk composition of Mars. Measurements of the radiogenic isotope and trace element concentrations of the shergottite meteorite suite have identified two end-members; (1) incompatible trace element enriched, with radiogenic Sr and negative epsilon Nd-143, and (2) incompatible traceelement depleted, with non-radiogenic Sr and positive epsilon 143-Nd(e.g. [3-5]). The depleted component represents the shergottite martian mantle. The identity of the enriched component is subject to debate, and has been proposed to be either assimilated ancient martian crust [3] or from enriched domains in the martian mantle that may represent a late-stage magma ocean crystallization residue [4,5]. Olivine-phyric shergottites typically have the highest Mg# of the shergottite group and represent near-primitive melts having experienced minimal fractional crystallization or crystal accumulation [6]. Olivine-hosted melt inclusions (MI) in these shergottites represent the most chemically primitive components available to understand the nature of their source(s), melting processes in the martian mantle, and origin of enriched components. We present trace element compositions of olivine hosted melt inclusions in two depleted olivinephyric shergottites, Yamato 980459 (Y98) and Tissint (Fig. 1), and the mesostasis glass of Y98, using Secondary Ionization Mass Spectrometry (SIMS). We discuss our data in the context of understanding the nature and origin of the depleted martian mantle and the emergence of the enriched component.

  6. Seismic structure of the western U.S. mantle and its relation to regional tectonic and magmatic activity

    Science.gov (United States)

    Schmandt, Brandon

    Vigorous convective activity in the western U.S. mantle has long been inferred from the region's widespread intra-plate crustal deformation, volcanism, and high elevations, but the specific form of convective activity and the degree and nature of lithospheric involvement have been strongly debated. I design a seismic travel-time tomography method and implement it with seismic data from the EarthScope Transportable Array and complementary arrays to constrain three-dimensional seismic structure beneath the western U.S. Tomographic images of variations in compressional velocity, shear velocity, and the ratio of shear to compressional velocity in the western U.S. mantle to a depth of 1000 km are produced. Using these results I investigate mantle physical properties, Cenozoic subduction history, and the influence of small-scale lithospheric convection on regional tectonic and magmatic activity, with particular focus on southern California and the Pacific Northwest. This dissertation includes previously published co-authored material. Chapter II presents a travel-time tomography method I designed and first implemented with data from southern California and the surrounding southwestern U.S. The resulting images provide a new level of constraint on upper mantle seismic anomalies beneath the Transverse Ranges, southern Great Valley, Salton Trough, and southwestern Nevada volcanic field. Chapter III presents tomographic images of the western U.S. mantle, identifies upper mantle volumes where partial melt is probable, and discusses implications of the apparently widespread occurrence of gravitational instabilities of continental lithsophere and the complex geometry and buoyancy of subducted ocean lithosphere imaged beneath the western U.S. In Chapter IV, tomography images are used in conjunction with geologic constraints on major transitions in crustal deformation and magmatism to construct a model for Pacific Northwest evolution since the Cretaceous. Accretion in the Pacific

  7. Coldspots and hotspots - Global tectonics and mantle dynamics of Venus

    Science.gov (United States)

    Bindschadler, Duane L.; Schubert, Gerald; Kaula, William M.

    1992-01-01

    Based on geologic observations provided by Magellan's first cycle of data collection and recent models of mantle convection in spherical shells and crustal deformation, the major topographic and geologic features of Venus are incorporated into a model of global mantle dynamics. Consideration is given to volcanic rises, such as Beta Regio and Atla Regio, plateau-shaped highlands dominated by complex ridged terrain (e.g., Ovda Regio and Alpha Regio), and circular lowland regions, such as Atalanta Planitia. Each of these features is related to either mantle plumes (hotspots) or mantle downwellings (coldspots).

  8. Osmium Isotopic Evolution of the Mantle Sources of Precambrian Ultramafic Rocks

    Science.gov (United States)

    Gangopadhyay, A.; Walker, R. J.

    2006-12-01

    The Os isotopic composition of the modern mantle, as recorded collectively by ocean island basalts, mid- oceanic ridge basalts (MORB) and abyssal peridotites, is evidently highly heterogeneous (γ Os(I) ranging from +25). One important question, therefore, is how and when the Earth's mantle developed such large-scale Os isotopic heterogeneities. Previous Os isotopic studies of ancient ultramafic systems, including komatiites and picrites, have shown that the Os isotopic heterogeneity of the terrestrial mantle can be traced as far back as the late-Archean (~ 2.7-2.8 Ga). This observation is based on the initial Os isotopic ratios obtained for the mantle sources of some of the ancient ultramafic rocks determined through analyses of numerous Os-rich whole-rock and/or mineral samples. In some cases, the closed-system behavior of these ancient ultramafic rocks was demonstrated via the generation of isochrons of precise ages, consistent with those obtained from other radiogenic isotopic systems. Thus, a compilation of the published initial ^{187}Os/^{188}Os ratios reported for the mantle sources of komatiitic and picritic rocks is now possible that covers a large range of geologic time spanning from the Mesozoic (ca. 89 Ma Gorgona komatiites) to the Mid-Archean (e.g., ca. 3.3 Ga Commondale komatiites), which provides a comprehensive picture of the Os isotopic evolution of their mantle sources through geologic time. Several Precambrian komatiite/picrite systems are characterized by suprachondritic initial ^{187}Os/^{188}Os ratios (e.g., Belingwe, Kostomuksha, Pechenga). Such long-term enrichments in ^{187}Os of the mantle sources for these rocks may be explained via recycling of old mafic oceanic crust or incorporation of putative suprachondritic outer core materials entrained into their mantle sources. The relative importance of the two processes for some modern mantle-derived systems (e.g., Hawaiian picrites) is an issue of substantial debate. Importantly, however, the

  9. COLLISIONS BETWEEN GRAVITY-DOMINATED BODIES. II. THE DIVERSITY OF IMPACT OUTCOMES DURING THE END STAGE OF PLANET FORMATION

    International Nuclear Information System (INIS)

    Stewart, Sarah T.; Leinhardt, Zoë M.

    2012-01-01

    Numerical simulations of the stochastic end stage of planet formation typically begin with a population of embryos and planetesimals that grow into planets by merging. We analyzed the impact parameters of collisions leading to the growth of terrestrial planets from recent N-body simulations that assumed perfect merging and calculated more realistic outcomes using a new analytic collision physics model. We find that collision outcomes are diverse and span all possible regimes: hit-and-run, merging, partial accretion, partial erosion, and catastrophic disruption. The primary outcomes of giant impacts between planetary embryos are approximately evenly split between partial accretion, graze-and-merge, and hit-and-run events. To explore the cumulative effects of more realistic collision outcomes, we modeled the growth of individual planets with a Monte Carlo technique using the distribution of impact parameters from N-body simulations. We find that fewer planets reached masses >0.7 M Earth using the collision physics model compared to simulations that assumed every collision results in perfect merging. For final planets with masses >0.7 M Earth , 60% are enriched in their core-to-mantle mass fraction by >10% compared to the initial embryo composition. Fragmentation during planet formation produces significant debris (∼15% of the final mass) and occurs primarily by erosion of the smaller body in partial accretion and hit-and-run events. In partial accretion events, the target body grows by preferentially accreting the iron core of the projectile and the escaping fragments are derived primarily from the silicate mantles of both bodies. Thus, the bulk composition of a planet can evolve via stochastic giant impacts.

  10. Randomized phase II study of a bendamustine monotherapy schedule for relapsed or refractory low-grade B-cell non-Hodgkin lymphoma or mantle cell lymphoma (RABBIT-14).

    Science.gov (United States)

    Itoh, Kuniaki; Igarashi, Tadahiko; Irisawa, Hiroyuki; Aotsuka, Nobuyuki; Masuda, Shinichi; Utsu, Yoshikazu; Tsujimura, Hideki; Tsukasaki, Kunihiro; Wakita, Hisashi

    2017-10-30

    The aim of this randomized phase II study was to improve the treatment delays and discontinuations associated with bendamustine use by comparing the effect of Benda-14 (intravenous bendamustine, 120 mg/m 2 on days 1 and 15, repeated every 4 weeks for a total of 6 cycles) with those of the standard treatment in relapsed indolent lymphoma and/or mantle cell lymphoma. Forty-six patients were randomly assigned to the treatments from September 2012 to February 2016. Treatment accomplishment rate and median relative dose intensity were similar in both arms: 38 and 63.4% in the Benda-14 arm and 41 and 66.3% in the standard treatment arm, respectively. The overall response rate and median progression-free survival, respectively, were 83% and 21.0 months for Benda-14, and 77% and 15.5 months for the standard treatment. Benda-14 induced favorable responses with less frequent hematological toxicities.

  11. Comparative Analysis between preoperative Radiotherapy and postoperative Radiotherapy in Clinical Stage I and II Endometrial Carcinoma

    International Nuclear Information System (INIS)

    Keum, Ki Chang; Lee, Chang Geol; Chung, Eun Ji; Lee, Sang Wook; Kim, Woo Cheol; Chang, Sei Kyung; Oh, Young Taek; Suh, Chang Ok; Kim, Gwi Eon

    1995-01-01

    Purpose : To obtain the optical treatment method in patients with endometrial carcinoma(clinical stage FIGO I, II) by comparative analysis between preoperative radiotherapy(pre-op R) and postoperative radiotherapy(post-op RT). Materials and Methods : A retrospective review of 62 endometrial carcinoma patients referred to the Yonsei Cancer Center for radiotherapy between 1985 and 1991 was undertaken. Of 62 patients, 19 patients(Stage I; 12 patients, Stage II; 7 patients) received pre-op RT before TAH(Total Abdominal Hysterectomy) and BSO(Bilateral Salphingoophorectomy) (Group 1) and 43 patients( Stage 1; 32 patients, Stage 2; 11 patients) received post-op RT after TAH and BSO (Group 2). Pre-op irradiation was given 4-6 weeks prior to surgery and post-op RT was administered on 4-5 weeks following surgery. All patients exept 1 patient(Group2; ICR alone) received external irradiation. Seventy percent(13/19) of pre-op RT group and 54 percent(23/42) of post-op RT group received external pelvic irradiation and intracavitary radiation therapy(ICR). External radiation dose was 39.6-55Gy(median 45Gy) in 5-6 week through opposed AP/PA fields or 4-field box technique treating daily, five days per week, 180cGy per fraction. ICR doses were prescribed to point A(20-39.6 Gy, median 39Gy) in Group 1 and 0.5cm depth from vaginal surface (18-30 Gy, median 21Gy) in Group2. Results : The overall 5 year survival rate was 95%. No survival difference between pre-op and post-op RT group.(89.3% vs 97.7%, p>0.1) There was no survival difference by stage, grade and histology between two groups. The survival rate was not affected by presence of residual tumor of surgical specimen after pre-op RT in Group 1(p>0.1), but affected by presence of lymph node metastasis in post-op RT group(p<0.5). The complication rate of pre-op RT group was higher than post-op RT.(16% vs 5%) Conclusion : Post-op radiotherapy offers the advantages of accurate surgical-pathological staging and low complication rate

  12. Magnitude corrections for attenuation in the upper mantle

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Since 1969, a consistent discrepancy in seismic magnitudes of nuclear detonations at NTS compared with magnitudes of detonations elsewhere in the world has been observed. This discrepancy can be explained in terms of a relatively high seismic attenuation for compressional waves in the upper mantle beneath the NTS and in certain other locations. A correction has been developed for this attenuation based on a relationship between the velocity of compressional waves at the top of the earth's mantle (just beneath the Mohorovicic discontinuity) and the seismic attenuation further down in the upper mantle. Our new definition of body-wave magnitude includes corrections for attenuation in the upper mantle at both ends of the teleseismic body-wave path. These corrections bring the NTS oservations into line with measurements of foreign events, and enable one to make more reliable estimates of yields of underground nuclear explosions, wherever the explosion occurs

  13. Assessment of local and regional isotopic equilibrium in the mantle

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, A W; Hart, S R [Carnegie Institution of Washington, D.C. (USA). Dept. of Terrestrial Magnetism

    1978-02-01

    The assumption of local equilibrium during partial melting is fundamental to the interpretation of isotope and trace element data for mantle-derived rocks. If disequilibrium melting is significant, the scale of the chemical and isotopic heterogeneity in the mantle indicated by the data could be as small as the grain size of the mantle rock, and the isotope data themselves are then of doubtful value to the understanding of mantle processes. To assess the scale of isotopic heterogeneity in a partially molten asthenosphere the authors review the Sr isotopic data of volcanic rocks from oceanic regions and the available experimental data on diffusion kinetics in minerals and melts similar to those existing in the mantle. Although diffusion data are scarce and afflicted with uncertainties, most of the diffusion coefficients for cations in mantle minerals at temperatures of 1000 to 1200/sup 0/C appear to be greater than 10/sup -13/ cm/sup 2/ s/sup -1/. Struntium diffusion in liquid basalt is more rapid, with diffusion coefficients of D = 10/sup -7/ to 10/sup -6/ cm/sup 2/ s/sup -1/ near 1300/sup 0/C. Simple model calculations show that, with these D values, a fluid-free mantle can maintain a state of disequilibrium on a centimeter scale for periods of 10/sup 8/ to 10/sup 9/ years. The state of disequilibrium found in many mantle-derived xenoliths is thus easily explained. A partially molten mantle, on the other hand, will tend to equilibrate locally in less than 10/sup 5/ to 10/sup 6/ years. The analytical data on natural rocks likewise indicate that the inhomogeneities are both old (> 1.5 b.y.) and regional in character and that the consistent isotopic differences between ocean island and ocean floor volcanics cannot be explained by small-scall hetorogeneity of the source rock.

  14. Seismic Evidence for Lower Mantle Plume Under the Yellowstone Hotspot

    Science.gov (United States)

    Nelson, P.; Grand, S.

    2017-12-01

    The mantle plume hypothesis for the origin of intraplate volcanism has been controversial since its inception in the 1970s. The hypothesis proposes hot narrow upwelling of rock rooted at the core mantle boundary (CMB) rise through the mantle and interact with the base of the lithosphere forming linear volcanic systems such as Hawaii and Yellowstone. Recently, broad lower mantle (>500 km in diameter) slow velocity conduits, most likely thermochemical in origin, have been associated with some intraplate volcanic provinces (French and Romanowicz, 2015). However, the direct detection of a classical thin thermal plume in the lower mantle using travel time tomography has remained elusive (Anderson and Natland, 2014). Here we present a new shear wave tomography model for the mantle beneath the western United States that is optimized to find short wavelength, sub-vertical structures in the lower mantle. Our approach uses carefully measured SKS and SKKS travel times recorded by dense North American seismic networks in conjunction with finite frequency kernels to build on existing tomography models. We find the presence of a narrow ( 300 km diameter) well isolated cylindrically shaped slow anomaly in the lower most mantle which we associate with the Yellowstone Hotspot. The conduit has a 2% reduction in shear velocity and is rooted at the CMB near the California/Arizona/Nevada border. A cross sectional view through the anomaly shows that it is slightly tilted toward the north until about 1300 km depth where it appears to weaken and deflect toward the surficial positon of the hotspot. Given the anomaly's strength, proximity to the Yellowstone Hotspot, and morphology we argue that a thermal plume interpretation is the most reasonable. Our results provide strong support for a lower mantle plume origin of the Yellowstone hotspot and more importantly the existence of deep thermal plumes.

  15. Steady state toroidal magnetic field at earth's core-mantle boundary

    Science.gov (United States)

    Levy, Eugene H.; Pearce, Steven J.

    1991-01-01

    Measurements of the dc electrical potential near the top of earth's mantle have been extrapolated into the deep mantle in order to estimate the strength of the toroidal magnetic field component at the core-mantle interface. Recent measurements have been interpreted as indicating that at the core-mantle interface, the magnetic toroidal and poloidal field components are approximately equal in magnitude. A motivation for such measurements is to obtain an estimate of the strength of the toroidal magnetic field in the core, a quantity important to our understanding of the geomagnetic field's dynamo generation. Through the use of several simple and idealized calculation, this paper discusses the theoretical relationship between the amplitude of the toroidal magnetic field at the core-mantle boundary and the actual amplitude within the core. Even with a very low inferred value of the toroidal field amplitude at the core-mantle boundary, (a few gauss), the toroidal field amplitude within the core could be consistent with a magnetohydrodynamic dynamo dominated by nonuniform rotation and having a strong toroidal magnetic field.

  16. Carcinoma microsatellite instability status as a predictor of benefit from fluorouracil-based adjuvant chemotherapy for stage II rectal cancer.

    Science.gov (United States)

    Yang, Liu; Sun, Yan; Huang, Xin-En; Yu, Dong-Sheng; Zhou, Jian-Nong; Zhou, Xin; Li, Dong-Zheng; Guan, Xin

    2015-01-01

    Rectal cancers with high microsatellite-instable have clinical and pathological features that differentiate them from microsatellite-stable or low- frequency carcinomas, which was studied rarely in stage II rectal cancer, promoting the present investigation of the usefulness of microsatellite-instability status as a predictor of the benefit of adjuvant chemotherapy with fluorouracil in stage II rectal cancer. Data of 460 patients who underwent primary anterior resection with a double stapling technique for rectal carcinoma at a single institution from 2008 to 2012 were retrospectively collected. All patients experienced a total mesorectal excision (TME) operation. Survival analysis were analyzed using the Cox regression method. Five-year rate of disease-free survival (DFS) was noted in 390 (84.8%) of 460 patients with stage II rectal cancer. Of 460 tissue specimens, 97 (21.1%) exhibited high-frequency microsatellite instability. Median age of the patients was 65 (50-71) and 185 (40.2%) were male. After univariate and multivariate analysis, microsatellite instability (p= 0.001), female sex (pchemotherapy (pchemotherapy, those cancers displaying high-frequency microsatellite instability had a better 5-year rate of DFS than tumors exhibiting microsatellite stability or low-frequency instability (HR, 13.61 [95% CI, 1.88 to 99.28]; p= 0.010), while in 259 patients who received adjuvant chemotherapy, there was no DFS difference between the two groups (p= 0.145). Furthermore, patients exhibiting microsatellite stability or low-frequency instability who received adjuvant chemotherapy had a better 5-year rate of DFS than patients did not (HR, 5.16 [95% CI, 2.90 to 9.18]; pchemotherapy and gender. Fluorouracil-based adjuvant chemotherapy benefits patients of stage II rectal cancer with microsatellite-stable or low microsatellite-instable, but not those with high microsatellite- instable. Additionally, free of adjuvant chemotherapy, carcinomas with high microsatellite

  17. Are stage IV vestibular schwannomas preoperatively different from other stages?

    Science.gov (United States)

    Tringali, Stéphane; Dubreuil, Christian; Zaouche, Sandra; Ferber-Viart, Chantal

    2008-01-01

    The aim of this study was to focus on the clinical and paraclinical symptoms of patients suffering from Stage IV vestibular schwannomas (VSs). In this prospective study, we included 734 patients who have VS and candidates for operation. Patients were classified as having Stage I, II, III, or IV tumors according to Tos criteria as evaluated by magnetic resonance imaging. PREOPERATIVE CLINICAL EVALUATION: We recorded the occurrence of complaints (%) and duration (yr) of hearing loss, tinnitus, and balance disorder. Preoperative paraclinical evaluation included pure-tone (PTA) and speech audiometry, auditory brainstem response (ABR) patterns, and vestibular deficit at videonystamography (VNG). Continuous variables were compared between Stage IV and other stages using analysis of variance. Qualitative variables expressed as a percentage of presence were compared between Stage IV and other stages using percentage comparison. Quantitative Parameters. Patients with Stage IV VS were significantly younger as compared with patients with other stages. Stage IV hearing loss was greater compared with other stages at 250 and 500 Hz but smaller at 2,000 and 8,000 Hz. We found no difference in the loss of PTA between Stage IV and the other stages. Speech discriminancy score was smaller in Stage IV. The durations of hearing loss, tinnitus, and balance disorders were similar whatever the tumor stage. Auditory brainstem response patterns showed no difference in Wave III latency between Stage IV VS and other stages, whereas Wave V latency and V-I interval were higher in Stage IV. Both ABR threshold and VNG caloric deficit were higher in Stage IV VS compared with other stages. Qualitative Parameters. The percentage of patients with Stage IV was lower than that with Stages II and III. The percentage of men and women was similar in all stages. The occurrence of hearing loss was similar in all stages, whereas that of tinnitus was lower in Stage IV compared with Stages I and II. In

  18. Nickel and helium evidence for melt above the core-mantle boundary.

    Science.gov (United States)

    Herzberg, Claude; Asimow, Paul D; Ionov, Dmitri A; Vidito, Chris; Jackson, Matthew G; Geist, Dennis

    2013-01-17

    High (3)He/(4)He ratios in some basalts have generally been interpreted as originating in an incompletely degassed lower-mantle source. This helium source may have been isolated at the core-mantle boundary region since Earth's accretion. Alternatively, it may have taken part in whole-mantle convection and crust production over the age of the Earth; if so, it is now either a primitive refugium at the core-mantle boundary or is distributed throughout the lower mantle. Here we constrain the problem using lavas from Baffin Island, West Greenland, the Ontong Java Plateau, Isla Gorgona and Fernandina (Galapagos). Olivine phenocryst compositions show that these lavas originated from a peridotite source that was about 20 per cent higher in nickel content than in the modern mid-ocean-ridge basalt source. Where data are available, these lavas also have high (3)He/(4)He. We propose that a less-degassed nickel-rich source formed by core-mantle interaction during the crystallization of a melt-rich layer or basal magma ocean, and that this source continues to be sampled by mantle plumes. The spatial distribution of this source may be constrained by nickel partitioning experiments at the pressures of the core-mantle boundary.

  19. Treatment outcome, body image, and sexual functioning after orchiectomy and radiotherapy for Stage I-II testicular seminoma

    International Nuclear Information System (INIS)

    Incrocci, Luca; Hop, Wim C.J.; Wijnmaalen, Arendjan; Slob, A. Koos

    2002-01-01

    Purpose: Orchiectomy followed by infradiaphragmatic irradiation is the standard treatment for Stage I-II testicular seminoma in The Netherlands. Because body image and sexual functioning can be affected by treatment, a retrospective study was carried out to assess treatment outcome, body image, and changes in sexuality after orchiectomy and radiotherapy. Methods and Materials: The medical charts of 166 patients with Stage I-II testicular seminoma were reviewed. A questionnaire on body image and current sexual functioning regarding the frequency and quality of erections, sexual activity, significance of sex, and changes in sexuality was sent to 157 patients (at a mean of 51 months after treatment). Results: Seventy-eight percent (n=123, mean age 42 years) completed the questionnaire. During irradiation, almost half of patients experienced nausea and 19% nausea and vomiting. Only 3 patients had disease relapse. After treatment, about 20% reported less interest and pleasure in sex and less sexual activity. Interest in sex, erectile difficulties, and satisfaction with sexual life did not differ from age-matched healthy controls. At the time of the survey, 17% of patients had erectile difficulties, a figure that was significantly higher than before treatment, but which correlated also with age. Twenty percent expressed concerns about fertility, and 52% found their body had changed after treatment. Cancer treatment had negatively influenced sexual life in 32% of the patients. Conclusions: Orchiectomy with radiotherapy is an effective and well-tolerated treatment for Stage I-II testicular seminoma. Treatment-induced changes in body image and concerns about fertility were detected, but the sexual problems encountered did not seem to differ from those of healthy controls, although baseline data are lacking

  20. ColoLipidGene: signature of lipid metabolism-related genes to predict prognosis in stage-II colon cancer patients

    Science.gov (United States)

    Vargas, Teodoro; Moreno-Rubio, Juan; Herranz, Jesús; Cejas, Paloma; Molina, Susana; González-Vallinas, Margarita; Mendiola, Marta; Burgos, Emilio; Aguayo, Cristina; Custodio, Ana B.; Machado, Isidro; Ramos, David; Gironella, Meritxell; Espinosa-Salinas, Isabel; Ramos, Ricardo; Martín-Hernández, Roberto; Risueño, Alberto; De Las Rivas, Javier; Reglero, Guillermo; Yaya, Ricardo; Fernández-Martos, Carlos; Aparicio, Jorge; Maurel, Joan; Feliu, Jaime; de Molina, Ana Ramírez

    2015-01-01

    Lipid metabolism plays an essential role in carcinogenesis due to the requirements of tumoral cells to sustain increased structural, energetic and biosynthetic precursor demands for cell proliferation. We investigated the association between expression of lipid metabolism-related genes and clinical outcome in intermediate-stage colon cancer patients with the aim of identifying a metabolic profile associated with greater malignancy and increased risk of relapse. Expression profile of 70 lipid metabolism-related genes was determined in 77 patients with stage II colon cancer. Cox regression analyses using c-index methodology was applied to identify a metabolic-related signature associated to prognosis. The metabolic signature was further confirmed in two independent validation sets of 120 patients and additionally, in a group of 264 patients from a public database. The combined analysis of these 4 genes, ABCA1, ACSL1, AGPAT1 and SCD, constitutes a metabolic-signature (ColoLipidGene) able to accurately stratify stage II colon cancer patients with 5-fold higher risk of relapse with strong statistical power in the four independent groups of patients. The identification of a group of 4 genes that predict survival in intermediate-stage colon cancer patients allows delineation of a high-risk group that may benefit from adjuvant therapy, and avoids the toxic and unnecessary chemotherapy in patients classified as low-risk group. PMID:25749516

  1. Short wavelength lateral variability of lithospheric mantle beneath the Middle Atlas (Morocco) as recorded by mantle xenoliths

    Science.gov (United States)

    El Messbahi, Hicham; Bodinier, Jean-Louis; Vauchez, Alain; Dautria, Jean-Marie; Ouali, Houssa; Garrido, Carlos J.

    2015-05-01

    The Middle Atlas is a region where xenolith-bearing volcanism roughly coincides with the maximum of lithospheric thinning beneath continental Morocco. It is therefore a key area to study the mechanisms of lithospheric thinning and constrain the component of mantle buoyancy that is required to explain the Moroccan topography. Samples from the two main xenolith localities, the Bou Ibalghatene and Tafraoute maars, have been investigated for their mineralogy, microstructures, crystallographic preferred orientation, and whole-rock and mineral compositions. While Bou Ibalghatene belongs to the main Middle Atlas volcanic field, in the 'tabular' Middle Atlas, Tafraoute is situated about 45 km away, on the North Middle Atlas Fault that separates the 'folded' Middle Atlas, to the South-East, from the 'tabular' Middle Atlas, to the North-West. Both xenolith suites record infiltration of sub-lithospheric melts that are akin to the Middle Atlas volcanism but were differentiated to variable degrees as a result of interactions with lithospheric mantle. However, while the Bou Ibalghatene mantle was densely traversed by high melt fractions, mostly focused in melt conduits, the Tafraoute suite records heterogeneous infiltration of smaller melt fractions that migrated diffusively, by intergranular porous flow. As a consequence the lithospheric mantle beneath Bou Ibalghaten was strongly modified by melt-rock interactions in the Cenozoic whereas the Tafraoute mantle preserves the record of extensional lithospheric thinning, most likely related to Mesozoic rifting. The two xenolith suites illustrate distinct mechanisms of lithospheric thinning: extensional thinning in Tafraoute, where hydrous incongruent melting triggered by decompression probably played a key role in favouring strain localisation, vs. thermal erosion in Bou Ibalghatene, favoured and guided by a dense network of melt conduits. Our results lend support to the suggestion that lithospheric thinning beneath the Atlas

  2. Gravitational Core-Mantle Coupling and the Acceleration of the Earth

    Science.gov (United States)

    Rubincam, David Parry; Smith, David E. (Technical Monitor)

    2001-01-01

    Gravitational core-mantle coupling may be the cause of the observed variable acceleration of the Earth's rotation on the 1000 year timescale. The idea is that density inhomogeneities which randomly come and go in the liquid outer core gravitationally attract density inhomogeneities in the mantle and crust, torquing the mantle and changing its rotation state. The corresponding torque by the mantle on the core may also explain the westward drift of the magnetic field of 0.2 deg per year. Gravitational core-mantle coupling would stochastically affect the rate of change of the Earth's obliquity by just a few per cent. Its contribution to polar wander would only be about 0.5% the presently observed rate. Tidal friction is slowing down the rotation of the Earth, overwhelming a smaller positive acceleration from postglacial rebound. Coupling between the liquid outer core of the Earth and the mantle has long been a suspected reason for changes in the length-of-day. The present investigation focuses on the gravitational coupling between the density anomalies in the convecting liquid outer core and those in the mantle and crust as a possible cause for the observed nonsecular acceleration on the millenial timescale. The basic idea is as follows. There are density inhomogeneities caused by blobs circulating in the outer core like the blobs in a lava lamp; thus the outer core's gravitational field is not featureless. Moreover, these blobs will form and dissipate somewhat randomly. Thus there will be a time variability to the fields. These density inhomogeneities will gravitationally attract the density anomalies in the mantle.

  3. Mantle cell lymphoma of the larynx: Primary case report

    Directory of Open Access Journals (Sweden)

    Naciri Sarah

    2012-07-01

    Full Text Available Abstract Introduction Primary laryngeal lymphomas are exceedingly rare. Only about a hundred cases have been reported. They consist mainly of non-Hodgkin lymphoma, especially of diffuse large B-cell lymphoma and mucosa-associated lymphoid tissue. We report the first case of a primary laryngeal mantle cell lymphoma. Case presentation We report a case of a primary mantle cell lymphoma of the larynx in a 70-year-old North African non-smoker male. We present a detailed report of his clinical and paraclinical data as well as treatment options. Conclusions Mantle cell lymphoma is a very aggressive lymphoma subset associated with poor prognosis. Laryngeal mantle cell lymphoma is exceedingly rare. To the best of our knowledge, this is the first case to ever be reported.

  4. The composition of interstellar grain mantles

    International Nuclear Information System (INIS)

    Tielens, A.G.G.M.

    1984-01-01

    The molecular composition of interstellar grain mantles employing gas phase as well as grain surface reactions has been calculated. The calculated mixtures consist mainly of the molecules H 2 O H 2 CO, N 2 , CO, O 2 , CO 2 , H 2 O 2 , NH 3 , and their deuterated counterparts in varying ratios. The exact compositions depend strongly on the physical conditions in the gas phase. The calculated mixtures are compared to the observations by using laboratory spectra of grain mantle analogs. (author)

  5. Teaching the Mantle Plumes Debate

    Science.gov (United States)

    Foulger, G. R.

    2010-12-01

    There is an ongoing debate regarding whether or not mantle plumes exist. This debate has highlighted a number of issues regarding how Earth science is currently practised, and how this feeds into approaches toward teaching students. The plume model is an hypothesis, not a proven fact. And yet many researchers assume a priori that plumes exist. This assumption feeds into teaching. That the plume model is unproven, and that many practising researchers are skeptical, may be at best only mentioned in passing to students, with most teachers assuming that plumes are proven to exist. There is typically little emphasis, in particular in undergraduate teaching, that the origin of melting anomalies is currently uncertain and that scientists do not know all the answers. Little encouragement is given to students to become involved in the debate and to consider the pros and cons for themselves. Typically teachers take the approach that “an answer” (or even “the answer”) must be taught to students. Such a pedagogic approach misses an excellent opportunity to allow students to participate in an important ongoing debate in Earth sciences. It also misses the opportunity to illustrate to students several critical aspects regarding correct application of the scientific method. The scientific method involves attempting to disprove hypotheses, not to prove them. A priori assumptions should be kept uppermost in mind and reconsidered at all stages. Multiple working hypotheses should be entertained. The predictions of a hypothesis should be tested, and unpredicted observations taken as weakening the original hypothesis. Hypotheses should not be endlessly adapted to fit unexpected observations. The difficulty with pedagogic treatment of the mantle plumes debate highlights a general uncertainty about how to teach issues in Earth science that are not yet resolved with certainty. It also represents a missed opportunity to let students experience how scientific theories evolve, warts

  6. Combined chemo-radiation therapy to adult patients with B-cell lymphoma in stage I and II

    International Nuclear Information System (INIS)

    Shimoyama, Masanori

    1988-01-01

    155 adult patients with B-lymphoma in stage I and II who were treated in National Cancer Center Hospital between 1975 and 1986 were analyzed for treatment outcome. 5-year survival rates were about 66 % in these patients and almost equal in the patients treated with radiation alone, doxorubicin-containing combination chemotherapy alone, or combined chemoradiation therapy. However, when analysis was limited to patients in stage I, patients treated with chemotherapy alone seemed to have better survival rate than those treated with radiation alone. In the patients who were in stage III or more and had bulky mass more than 10 cm in diameter, small residual tumor was sometimes detected by restaging procedure after achieving apparent remission by multi-drug chemotherapy. In these patients, additional radiation therapy was quite usefull to eradicate residual tumor cell to cure. (author)

  7. Late-orogenic mantle garnet pyroxenites evidence mantle refertilization during exhumation of orogenic belt

    Science.gov (United States)

    Chazot, G.; France, L.; Kornprobst, J.; Dallai, L.; Vannucci, R.

    2008-12-01

    The petrological and geochemical study of garnet bearing pyroxenites from four localities (FMC, Morocco, Jordan, Cameroon) demonstrates that these rocks are cumulates crystallised in the lithospheric mantle domain. Metamorphic reactions, exsolutions and trace elements WR analysis demonstrate that their crystallisation pressure ranges between 1 and 2GPa (30 to 60km). The elaboration of the PTt paths for the studied samples attests of important movements in the respective lithospheres. Replaced in the geodynamical contexts, the samples are interpreted to represent the crystallisation of melts formed during exhumation of orogenic domains. Radiogenic isotopes (Sr-Nd) show that in a very same region, the samples are isotopicaly heterogeneous but are similar to the respective regional lithosphere. Initial isotopic ratios lead to propose that the FMC samples have crystallised at the end of the Hercynian orogen and that the samples from the other localities (Morocco, Jordan and Cameroon) have crystallised at the end of the Pan-African orogen. After recalculation at the crystallisation time, the isotopic compositions are in good agreement with the respective regional lithosphere ones and so samples of this study could represent the product of the melting of these lithospheres. The analyses of oxygen stable isotopes allow to precise the model; they show that twelve of the samples come from the melting of a lherzolitic mantle and that the four others come from the melting of a heterogeneous mantle formed of lherzolites and eclogites. The presence of some hydrous minerals such as amphiboles and micas and the trace elements WR analyses show that some of the samples were affected by a late metasomatic event. Results of our study show that thermal relaxation following orogenic events lead to the crystallisation of pyroxenites in the lithosphere. The presence of lage amounts of mantle pyroxenites in old orogenic regions confers physical and chemical particularities to these

  8. The role of upper mantle mineral phase transitions on the current structure of large-scale Earth's mantle convection.

    Science.gov (United States)

    Thoraval, C.

    2017-12-01

    Describing the large-scale structures of mantle convection and quantifying the mass transfer between upper and lower mantle request to account for the role played by mineral phase transitions in the transition zone. We build a density distribution within the Earth mantle from velocity anomalies described by global seismic tomographic models. The density distribution includes thermal anomalies and topographies of the phase transitions at depths of 410 and 660 km. We compute the flow driven by this density distribution using a 3D spherical circulation model, which account for depth-dependent viscosity. The dynamic topographies at the surface and at the CMB and the geoid are calculated as well. Within the range of viscosity profiles allowing for a satisfying restitution of the long wavelength geoid, we perform a parametric study to decipher the role of the characteristics of phase diagrams - mainly the Clapeyron's slopes - and of the kinetics of phase transitions, which may modify phase transition topographies. Indeed, when a phase transition is delayed, the boundary between two mineral phases is both dragged by the flow and interfere with it. The results are compared to recent estimations of surface dynamic topography and to the phase transition topographies as revealed by seismic studies. The consequences are then discussed in terms of structure of mantle flow. Comparisons between various tomographic models allow us to enlighten the most robust features. At last, the role played by the phase transitions on the lateral variations of mass transfer between upper and lower mantle are quantified by comparison to cases with no phase transitions and confronted to regional tomographic models, which reflect the variability of the behaviors of the descending slabs in the transition zone.

  9. The benefit of microsatellite instability is attenuated by chemotherapy in stage II and stage III gastric cancer: Results from a large cohort with subgroup analyses.

    Science.gov (United States)

    Kim, Soo Young; Choi, Yoon Young; An, Ji Yeong; Shin, Hyun Beak; Jo, Ara; Choi, Hyeji; Seo, Sang Hyuk; Bang, Hui-Jae; Cheong, Jae-Ho; Hyung, Woo Jin; Noh, Sung Hoon

    2015-08-15

    We previously reported that the prognosis of microsatellite instability high (MSI-H) gastric cancer is similar to that of MSI-low/microsatellite stable (MSI-L/MSS) gastric cancer. The reason for this seemed to be related to the effects of chemotherapy. To verify this hypothesis, we expanded the study population and reanalyzed the prognosis of MSI-H gastric cancer. Data from 1,276 patients with Stage II and III gastric cancer who underwent gastrectomy with curative intent between January 2005 and June 2010 were reviewed. The prognosis of MSI-H tumors in comparison with MSI-L/MSS tumors was analyzed, according to the administration of chemotherapy and other clinicopathologic features. A total of 361 (28.3%) patients did not receive chemotherapy (MSI-H = 47 and MSI-L/MSS = 314), whereas 915 (71.7%) patients did receive chemotherapy (MSI-H = 58 and MSI-L/MSS = 857). The hazard ratio of MSI-H versus MSI-L/MSS was 0.49 (95% confidence interval: 0.26-0.94, p = 0.031) when chemotherapy was not received and 1.16 (95% confidence interval: 0.78-1.71, p = 0.466) when chemotherapy was received. In subgroup analyses, the prognosis of MSI-H was better in Stage III, women, with lymph node metastasis, and undifferentiated histology subgroups when chemotherapy was not received. However, in patients treated with chemotherapy, prognosis was worse for MSI-H tumors in Stage III, undifferentiated histology, and diffuse type subgroups of gastric cancer. In conclusion, MSI-H tumors were associated with a good prognosis in Stage II and III gastric cancer when patients were treated by surgery alone, and the benefits of MSI-H status were attenuated by chemotherapy. © 2015 UICC.

  10. Geochemical Constraints on Core-Mantle Interaction from Fe/Mn Ratios

    Science.gov (United States)

    Humayun, M.; Qin, L.

    2003-12-01

    The greater density of liquid iron alloy, and its immiscibility with silicate, maintains the physical separation of the core from the mantle. There are no a priori reasons, however, why the Earth's mantle should be chemically isolated from the core. Osmium isotopic variations in mantle plumes have been interpreted in terms of interaction between outer core and the source regions of deep mantle plumes. If chemical transport occurs across the core-mantle boundary its mechanism remains to be established. The Os isotope evidence has also been interpreted as the signatures of subducted Mn-sediments, which are known to have relatively high Pt/Os. In the mantle, Fe occurs mainly as the divalent ferrous ion, and Mn occurs solely as a divalent ion, and both behave in a geochemically coherent manner because of similarity in ionic charge and radius. Thus, the Fe/Mn ratio is a planetary constant insensitive to processes of mantle differentiation by partial melting. Two processes may perturb the ambient mantle Fe/Mn of 60: a) the subduction of Mn-sediments should decrease the Fe/Mn ratio in plume sources, while b) chemical transport from the outer core may increase the Fe/Mn ratio. The differentiation of the liquid outer core to form the solid inner core may increase abundances of the light element constituents (FeS, FeO, etc.) to the point of exsolution from the core at the CMB. The exact rate of this process is determined by the rate of inner core growth. Two end-member models include 1) inner core formation mainly prior to 3.5 Ga with heat release dominated by radioactive sources, or 2) inner core formation occurring mainly in the last 1.5 Ga with heat release dominated by latent heat. This latter model would imply large fluxes of Fe into the sources of modern mantle plumes. Existing Fe/Mn data for Gorgona and Hawaiian samples place limits on both these processes. We describe a new procedure for the precise determination of the Fe/Mn ratio in magmatic rocks by ICP-MS. This

  11. Surgical resection of locally advanced primary transverse colon cancer--not a worse outcome in stage II tumor.

    Science.gov (United States)

    Hung, Hsin-Yuan; Yeh, Chien-Yuh; Changchien, Chung-Rong; Chen, Jinn-Shiun; Fan, Chung-Wei; Tang, Reiping; Hsieh, Pao-Shiu; Tasi, Wen-Sy; You, Yau-Tong; You, Jeng-Fu; Wang, Jeng-Yi; Chiang, Jy-Ming

    2011-07-01

    In locally advanced primary transverse colon cancer, a tumor may cause perforation or invade adjacent organs. Extensive resection is the best choice of treatment, but such procedures must be weighed against the potential survival benefits. This study was performed to identify the clinicopathological features and treatment outcomes of such tumors. We retrospectively reviewed the database of the Colorectal Cancer Registry of Chang Gung Memorial Hospital between February 1995 and December 2005. Patients with colon cancer sited between the hepatic and splenic flexure that involved an adjacent organ without distant metastasis were defined as having locally advanced transverse colon cancer. A total of 827 patients who underwent surgery for transverse primary colon cancer were enrolled in the study. Stage II and stage III colon cancer were diagnosed in 548 patients. Thirty-two (5.8%) patients were diagnosed with locally advanced tumors. Multivariate analysis revealed that stage III, preoperative carcinoembryonic antigen ≥5 ng/mL, a tumor with perforation or obstruction, and the presence of a locally advanced tumor were significant prognostic factors for both overall and cancer-specific survival. Postoperative morbidity rates differed significantly between the locally advanced and non-locally advanced tumor groups (22.7% vs. 12.3%, P transverse colon tumors (P = 0.21). Surgical resection of locally advanced transverse colon tumors resulted in a higher morbidity and mortality than that of non-locally advanced tumors, but the benefit of extensive surgery in the case of locally advanced tumors cannot be underestimated. Furthermore, this benefit is more pronounced in the case of stage II tumors.

  12. Lower-mantle plume beneath the Yellowstone hotspot revealed by core waves

    Science.gov (United States)

    Nelson, Peter L.; Grand, Stephen P.

    2018-04-01

    The Yellowstone hotspot, located in North America, is an intraplate source of magmatism the cause of which is hotly debated. Some argue that a deep mantle plume sourced at the base of the mantle supplies the heat beneath Yellowstone, whereas others claim shallower subduction or lithospheric-related processes can explain the anomalous magmatism. Here we present a shear wave tomography model for the deep mantle beneath the western United States that was made using the travel times of core waves recorded by the dense USArray seismic network. The model reveals a single narrow, cylindrically shaped slow anomaly, approximately 350 km in diameter that we interpret as a whole-mantle plume. The anomaly is tilted to the northeast and extends from the core-mantle boundary to the surficial position of the Yellowstone hotspot. The structure gradually decreases in strength from the deepest mantle towards the surface and if it is purely a thermal anomaly this implies an initial excess temperature of 650 to 850 °C. Our results strongly support a deep origin for the Yellowstone hotspot, and also provide evidence for the existence of thin thermal mantle plumes that are currently beyond the resolution of global tomography models.

  13. An inverted continental Moho and serpentinization of the forearc mantle.

    Science.gov (United States)

    Bostock, M G; Hyndman, R D; Rondenay, S; Peacock, S M

    2002-05-30

    Volatiles that are transported by subducting lithospheric plates to depths greater than 100 km are thought to induce partial melting in the overlying mantle wedge, resulting in arc magmatism and the addition of significant quantities of material to the overlying lithosphere. Asthenospheric flow and upwelling within the wedge produce increased lithospheric temperatures in this back-arc region, but the forearc mantle (in the corner of the wedge) is thought to be significantly cooler. Here we explore the structure of the mantle wedge in the southern Cascadia subduction zone using scattered teleseismic waves recorded on a dense portable array of broadband seismometers. We find very low shear-wave velocities in the cold forearc mantle indicated by the exceptional occurrence of an 'inverted' continental Moho, which reverts to normal polarity seaward of the Cascade arc. This observation provides compelling evidence for a highly hydrated and serpentinized forearc region, consistent with thermal and petrological models of the forearc mantle wedge. This serpentinized material is thought to have low strength and may therefore control the down-dip rupture limit of great thrust earthquakes, as well as the nature of large-scale flow in the mantle wedge.

  14. Role of Surgery in Stages II and III Pediatric Abdominal Non-Hodgkin Lymphoma: A 5-Years Experience.

    Science.gov (United States)

    Ali, Amany M; Sayd, Heba A; Hamza, Hesham M; Salem, Mohamed A

    2011-03-29

    Abdominal Non-Hodgkin lymphomas (NHL) are the most common extra nodal presentation of pediatric NHL. Our aim is to assess the role of surgery as a risk factor and to evaluate the impact of risk-adjusted systemic chemotherapy on survival of patients with stages II and III disease. This study included 35 pediatric patients with abdominal NHL treated over five years at South Egypt Cancer Institute (SECI), Assiut University, between January 2005 and January 2010. The data of every patient included: Age, sex, and presentation, staging work up to determine extent of the disease and the type of resection performed, histopathological examination, details of chemotherapy, disease free survival and overall survival. The study included 25 boys and 10 girls with a median age of six years (range: 2.5:15). Thirty patients (86%) presented with abdominal pain, 23 patients (66%) presented with abdominal mass and distention, 13 patients (34%) presented with weight loss, and intestinal obstruction occurred in six patients (17%). The ileo-cecal region and abdominal lymph nodes were the commonest sites (48.5%, 21% respectively). Burkitt's lymphoma was the most common histological type in 29 patients (83%). Ten (28.5%) stage II (group A) and 25 (71.5%) stage III (group B). Complete resections were performed in 10 (28.5%), debulking in 6 (17%) and imaging guided biopsy in 19 (54%). A11 patients received systemic chemotherapy. The median follow up duration was 63 months (range 51-78 months). The parameters that significantly affect the overall survival were stage at presentation complete resection for localized disease. In conclusion, the extent of disease at presentation is the most important prognostic factor in pediatric abdominal NHL. Surgery is restricted to defined situations such as; abdominal emergencies, diagnostic biopsy and total tumor extirpation in localized disease. Chemotherapy is the cornerstone in the management of pediatric abdominal NHL.

  15. Role of Surgery in Stages II and III Pediatric Abdominal Non-Hodgkin Lymphoma: A 5-Years Experience

    Directory of Open Access Journals (Sweden)

    Mohamed A. Salem

    2011-03-01

    Full Text Available Abdominal Non-Hodgkin lymphomas (NHL are the most common extra nodal presentation of pediatric NHL. Our aim is to assess the role of surgery as a risk factor and to evaluate the impact of risk-adjusted systemic chemotherapy on survival of patients with stages II and III disease. This study included 35 pediatric patients with abdominal NHL treated over five years at South Egypt Cancer Institute (SECI, Assiut University, between January 2005 and January 2010. The data of every patient included: Age, sex, and presentation, staging work up to determine extent of the disease and the type of resection performed, histopathological examination, details of chemotherapy, disease free survival and overall survival. The study included 25 boys and 10 girls with a median age of six years (range: 2.5:15. Thirty patients (86% presented with abdominal pain, 23 patients (66% presented with abdominal mass and distention, 13 patients (34% presented with weight loss, and intestinal obstruction occurred in six patients (17%. The ileo-cecal region and abdominal lymph nodes were the commonest sites (48.5%, 21% respectively. Burkitt's lymphoma was the most common histological type in 29 patients (83%. Ten (28.5% stage II (group A and 25 (71.5% stage III (group B. Complete resections were performed in 10 (28.5%, debulking in 6 (17% and imaging guided biopsy in 19 (54%. A11 patients received systemic chemotherapy. The median follow up duration was 63 months (range 51-78 months. The parameters that significantly affect the overall survival were stage at presentation complete resection for localized disease. In conclusion, the extent of disease at presentation is the most important prognostic factor in pediatric abdominal NHL. Surgery is restricted to defined situations such as; abdominal emergencies, diagnostic biopsy and total tumor extirpation in localized disease. Chemotherapy is the cornerstone in the management of pediatric abdominal NHL.

  16. Secondary overprinting of S-Se-Te signatures in the Earth's mantle: Implications for the Late Veneer

    Science.gov (United States)

    Koenig, S.; Luguet, A.; Lorand, J.; Pearson, D.

    2013-12-01

    Sulphur, Selenium and Tellurium are both chalcophile and highly siderophile elements (HSE) with near-chondritic ratios and absolute abundances in the terrestrial mantle that exceed those predicted by core-mantle differentiation[1]. These 'excess' HSE abundances have been attributed to addition of ca. 0.5% of chondrite-like material that hit the Earth in its accretionary stage between 4 to 3.8 billion years ago after core-mantle differentiation (Late Veneer[2]). Therefore, like other HSE, S, Se and Te are considered potential tracers for the composition of the Late Veneer, provided that their bulk silicate Earth abundances are properly constrained. In contrast to ca. 250 ppm S, Se and Te are ultra-trace elements in the terrestrial mantle. Like all HSE, they are furthermore controlled by base metal sulphides (BMS) and micrometric platinum group minerals (PGMs)[3]. This strong control exerted by the host mineralogy and petrology on the S-Se-Te systematics at both the micro-scale and the whole-rock scale makes detailed mineralogical and petrological studies of BMS and PGM a pre-requisite to fully understand and accurately interpret the whole-rock signatures. Here we combine in-situ sulphide data and detailed mineralogical observations with whole-rock S-Se-Te-HSE signatures of both lherzolites and harburgites from different geodynamic settings. We demonstrate that the near-chondritic Se and Te signature of 'fertile' mantle rocks (Se/Te ≈9×5) is not a primitive signature of the Earth's mantle, but rather reflects strong enrichment in metasomatic HSE host phases, which erased previous pristine signatures. Consequently, current attempts to identify a potential Late Veneer composition are seriously flawed because, neither refertilisation/metasomatism nor true melt depletion (e.g. harzburgitic residues) have been taken into account for the Primitive Upper Mantle composition estimate[4]. Our combined whole rock and in-situ sulphide data indicate a refertilisation trend

  17. The viscosity of Earth's lower mantle inferred from sinking speed of subducted lithosphere

    NARCIS (Netherlands)

    Čížková, H.; van den Berg, A.P.; Spakman, W.; Matyska, C.

    2012-01-01

    The viscosity of the mantle is indispensable for predicting Earth's mechanical behavior at scales ranging from deep mantle material flow to local stress accumulation in earthquakes zones. But, mantle viscosity is not well determined. For the lower mantle, particularly, only few constraints result

  18. Development and independent validation of a prognostic assay for stage II colon cancer using formalin-fixed paraffin-embedded tissue.

    LENUS (Irish Health Repository)

    Kennedy, Richard D

    2011-12-10

    Current prognostic factors are poor at identifying patients at risk of disease recurrence after surgery for stage II colon cancer. Here we describe a DNA microarray-based prognostic assay using clinically relevant formalin-fixed paraffin-embedded (FFPE) samples.

  19. The upper-mantle transition zone beneath the Chile-Argentina flat subduction zone

    Science.gov (United States)

    Bagdo, Paula; Bonatto, Luciana; Badi, Gabriela; Piromallo, Claudia

    2016-04-01

    The main objective of the present work is the study of the upper mantle structure of the western margin of South America (between 26°S and 36°S) within an area known as the Chile-Argentina flat subduction zone. For this purpose, we use teleseismic records from temporary broad band seismic stations that resulted from different seismic experiments carried out in South America. This area is characterized by on-going orogenic processes and complex subduction history that have profoundly affected the underlying mantle structure. The detection and characterization of the upper mantle seismic discontinuities are useful to understand subduction processes and the dynamics of mantle convection; this is due to the fact that they mark changes in mantle composition or phase changes in mantle minerals that respond differently to the disturbances caused by mantle convection. The discontinuities at a depth of 410 km and 660 km, generally associated to phase changes in olivine, vary in width and depth as a result of compositional and temperature anomalies. As a consequence, these discontinuities are an essential tool to study the thermal and compositional structure of the mantle. Here, we analyze the upper-mantle transition zone discontinuities at a depth of 410 km and 660 km as seen from Pds seismic phases beneath the Argentina-Chile flat subduction.

  20. Mantle viscosity structure constrained by joint inversions of seismic velocities and density

    Science.gov (United States)

    Rudolph, M. L.; Moulik, P.; Lekic, V.

    2017-12-01

    The viscosity structure of Earth's deep mantle affects the thermal evolution of Earth, the ascent of mantle upwellings, sinking of subducted oceanic lithosphere, and the mixing of compositional heterogeneities in the mantle. Modeling the long-wavelength dynamic geoid allows us to constrain the radial viscosity profile of the mantle. Typically, in inversions for the mantle viscosity structure, wavespeed variations are mapped into density variations using a constant- or depth-dependent scaling factor. Here, we use a newly developed joint model of anisotropic Vs, Vp, density and transition zone topographies to generate a suite of solutions for the mantle viscosity structure directly from the seismologically constrained density structure. The density structure used to drive our forward models includes contributions from both thermal and compositional variations, including important contributions from compositionally dense material in the Large Low Velocity Provinces at the base of the mantle. These compositional variations have been neglected in the forward models used in most previous inversions and have the potential to significantly affect large-scale flow and thus the inferred viscosity structure. We use a transdimensional, hierarchical, Bayesian approach to solve the inverse problem, and our solutions for viscosity structure include an increase in viscosity below the base of the transition zone, in the shallow lower mantle. Using geoid dynamic response functions and an analysis of the correlation between the observed geoid and mantle structure, we demonstrate the underlying reason for this inference. Finally, we present a new family of solutions in which the data uncertainty is accounted for using covariance matrices associated with the mantle structure models.

  1. The Interaction Between Supercontinent Cycles and Compositional Variations in the Deep Mantle

    Science.gov (United States)

    Lowman, J. P.; Trim, S. J.

    2015-12-01

    Earth is the only planet known to currently feature active plate tectonics. Two features that may influence the Earth's ability to sustain plate-like surface motion are the presence of continents and the inferred chemical piles lying on the core mantle boundary. In our previous study that modelled thermochemical convection in the mantle with evolving plates, it was shown that upwellings that form on top of chemical piles are relatively weak and make a diminished contribution to lithospheric stress. Yet, surface yielding is required in order to maintain plate tectonics and form new plate boundaries. Consequently an intrinsically dense layer in the lower mantle can decrease the vigour of convection and the likelihood of surface failure. In contrast to the mantle upwellings that form above the chemically dense provinces in our models, particularly vigorous plumes form where the ambient mantle lies adjacent to the core mantle boundary and at the edges of the chemically dense piles. Continents also affect surface mobility, due to their inherent buoyancy and their distinct yield strength. In this study we employ numerical models of mantle convection featuring both tectonic plates and compositional variation in the mantle and lithosphere. Plate-like surface motion is dynamically modelled using a force-balance method that determines plate velocities based upon lithospheric stresses. Oceanic and continental margins evolve in response to the plate velocities and specified lithospheric yield stresses. Compositional variations in the deep mantle are tracked using the tracer ratio method. For a range of ratios of the ambient mantle density to the density of the compositionally enriched material, we examine the the impact of mantle compositional variation on plate evolution, the effect of continents on planetary surface mobility and the frequency of supercontinent assembly versus the mobility of compositional provinces.

  2. Thymidine phosphorylase and hypoxia-inducible factor 1-α expression in clinical stage II/III rectal cancer: association with response to neoadjuvant chemoradiation therapy and prognosis.

    Science.gov (United States)

    Lin, Shuhan; Lai, Hao; Qin, Yuzhou; Chen, Jiansi; Lin, Yuan

    2015-01-01

    The aim of this study was to determine whether pretreatment status of thymidine phosphorylase (TP), and hypoxia-inducible factor alpha (HIF-1α) could predict pathologic response to neoadjuvant chemoradiation therapy with oxaliplatin and capecitabine (XELOXART) and outcomes for clinical stage II/III rectal cancer patients. A total of 180 patients diagnosed with clinical stage II/III rectal cancer received XELOXART. The status of TP, and HIF-1α were determined in pretreatment biopsies by immunohistochemistry (IHC). Tumor response was assessed in resected regimens using the tumor regression grade system and TNM staging system. 5-year disease free survival (DFS) and 5-year overall survival (OS) were evaluated with the Kaplan-Meier method and were compared by the log-rank test. Over expression of TP and low expression of HIF-1α were associated with pathologic response to XELOXART and better outcomes (DFS and OS) in clinical stage II/III rectal cancer patients (P rectal cancer received XELOXART. Additional well-designed, large sample, multicenter, prospective studies are needed to confirm the result of this study.

  3. Coupling surface and mantle dynamics: A novel experimental approach

    Science.gov (United States)

    Kiraly, Agnes; Faccenna, Claudio; Funiciello, Francesca; Sembroni, Andrea

    2015-05-01

    Recent modeling shows that surface processes, such as erosion and deposition, may drive the deformation of the Earth's surface, interfering with deeper crustal and mantle signals. To investigate the coupling between the surface and deep process, we designed a three-dimensional laboratory apparatus, to analyze the role of erosion and sedimentation, triggered by deep mantle instability. The setup is constituted and scaled down to natural gravity field using a thin viscous sheet model, with mantle and lithosphere simulated by Newtonian viscous glucose syrup and silicon putty, respectively. The surface process is simulated assuming a simple erosion law producing the downhill flow of a thin viscous material away from high topography. The deep mantle upwelling is triggered by the rise of a buoyant sphere. The results of these models along with the parametric analysis show how surface processes influence uplift velocity and topography signals.

  4. On the Role of Mantle Overturn during Magma Ocean Solidification

    Science.gov (United States)

    Boukaré, C. E.; Parmentier, E.; Parman, S. W.

    2017-12-01

    Solidification of potential global magma ocean(s) (MO) early in the history of terrestrial planets may play a key role in the evolution of planetary interiors by setting initial conditions for their long-term evolution. Constraining this initial structure of solid mantles is thus crucial but remains poorly understood. MO fractional crystallization has been proposed to generate gravitationally unstable Fe-Mg chemical stratification capable of driving solid-state mantle overturn. Fractional solidification and overturn hypothesis, while only an ideal limiting case, can explain important geochemical features of both the Moon and Mars. Current overturn models consider generally post-MO overturn where the cumulate pile remains immobile until the end of MO solidification. However, if the cumulate pile overturns during MO solidification, the general picture of early planet evolution might differ significantly from the static crystallization models. We show that the timing of mantle overturn can be characterized with a dimensionless number measuring the ratio of the MO solidification time and the purely compositional overturn timescale. Syn-solidification overturn occurs if this dimensionless parameter, Rc, exceeds a critical value. Rc is mostly affected by the competition between the MO solidification time and mantle viscosity. Overturn that occurs during solidification can result in smaller scales of mantle chemical heterogeneity that could persist for long times thus influencing the whole evolution of a planetary body. We will discuss the effects of compaction/percolation on mantle viscosity. If partially molten cumulate do not have time to compact during MO solidification, viscosity of cumulates would be significantly lower as the interstitcial melt fraction would be large. Both solid mantle remelting during syn-solidification overturn and porous convection of melt retained with the cumulates are expected to reduce the degree of fractional crystallization. Syn

  5. Electrical conductivity of partially-molten olivine aggregate and melt interconnectivity in the oceanic upper mantle

    Science.gov (United States)

    Laumonier, Mickael; Frost, Dan; Farla, Robert; Katsura, Tomoo; Marquardt, Katharina

    2016-04-01

    A consistent explanation for mantle geophysical anomalies such as the Lithosphere-Astenosphere Boundary (LAB) relies on the existence of little amount of melt trapped in the solid peridotite. Mathematical models have been used to assess the melt fraction possibly lying at mantle depths, but they have not been experimentally checked at low melt fraction (Lanzarote, Canary Islands, Spain) containing various amount of basaltic (MORB-like composition) melt (0 to 100%) at upper mantle conditions. We used the MAVO 6-ram press (BGI) combined with a Solartron gain phase analyser to acquire the electrical resistance of the sample at pressure of 1.5 GPa and temperature up to 1400°C. The results show the increase of the electrical conductivity with the temperature following an Arrhenius law, and with the melt fraction, but the effect of pressure between 1.5 and 3.0 GPa was found negligible at a melt fraction of 0.5 vol.%. The conductivity of a partially molten aggregate fits the modified Archie's law from 0.5 to 100 vol.%. At melt fractions of 0.25, 0.15 and 0.0 vol.%, the EC value deviates from the trend previously defined, suggesting that the melt is no longer fully interconnected through the sample, also supported by chemical mapping. Our results extend the previous results obtained on mixed system between 1 and 10% of melt. Since the melt appears fully interconnected down to very low melt fraction (0.5 vol.%), we conclude that (i) only 0.5 to 1 vol.% of melt is enough to explain the LAB EC anomaly, lower than previously determined; and (ii) deformation is not mandatory to enhance electrical conductivity of melt-bearing mantle rocks.

  6. Universal single grain amphibole thermobarometer for mantle rocks - preliminary calibration.

    Science.gov (United States)

    Ashchepkov, Igor

    2017-04-01

    Calibration of S-Al- K-Na-Ca distribution in the structure of the mantle amphiboles (Cr- hornblende, pargasite, kaersutite) using experimental data (Niida, Green, 1999; Wallace Green, 1991, Conceicao, Green, 2004; Medard et al, 2006; Safonov, Butvina, 2013; 2016; Pirard, Hermann, 2015 etc) allows to obtain an equation for pressure estimates in 0.5 - 4.5 GPa interval. Regression calculated pressures with experimental values (R 0.82) and precision 5 kbar allow to use barometer for a wide range of mantle rocks from peridotite to pyroxenites and megacrystals. For the higher pressures (Cr- pargasite richterite) calibration is carried by the cross- correlations with the estimates calculated for the natural associations obtained using clino- and orthopyroxene. IT was used KD =Si/(8-Al-2.2*Ti)*(Na+K))/Ca for the following equation: P(GPa)=0.0035*(4+K/(Na+K))*2*Mg)/Fe+3.75*(K+Na)/Ca))*KD*ToK**0.75/ (1+3.32*Fe)-ln(1273/ToK*5*(8*Mg-Al*2 +3*Ti+8*Cr+3*K)/10 Th advantage of this barometer comparing with the previous (Ridolfi, Renzulli, 2012) is that is working with all mantle amphibole types. For the calculations of the PT parameters of the natural xenocrysts it was used monomineral version of Gar-Amph termometer (Ravna et al., 2000) in combination with the received barometer. Contents of Ca- Mg and Fe in associated garnets were calculated usinf the regressions obtained from natural and experimental associations. Aplication of the mantle amphibole thermobarometry for the reconstruction of sections of the cratonic mantle lithosphere of Yakutia show that amphibloles are distributed in various parts of mantle sections in deifferent mantle terranes of Yakutia. The most abundant amphoboles from Alakite region are distributed within all mantle section. In the SCLM beneat Yubileyaya pipe thehalf of them belong to the spinel garnet facie refering to the upper pyroxenitic suit and Cr- hornblende - mica viens. The second group reffer to the eclogite pyroxenite layer in the middle part of

  7. Analysis of the flow structure and heat transfer in a vertical mantle heat exchanger

    DEFF Research Database (Denmark)

    Knudsen, Søren; Morrison, GL; Behnia, M

    2005-01-01

    initially mixed and initially stratified inner tank and mantle. The analysis of the heat transfer showed that the flow in the mantle near the inlet is mixed convection flow and that the heat transfer is dependent on the mantle inlet temperature relative to the core tank temperature at the mantle level. (C......The flow structure inside the inner tank and inside the mantle of a vertical mantle heat exchanger was investigated using a full-scale tank designed to facilitate flow visualisation. The flow structure and velocities in the inner tank and in the mantle were measured using a Particle Image...... Velocimetry (PIV) system. A Computational Fluid Dynamics (CFD) model of the vertical mantle heat exchanger was also developed for a detailed evaluation of the heat flux at the mantle wall and at the tank wall. The flow structure was evaluated for both high and low temperature incoming flows and for both...

  8. Mixing properties of thermal convection in the earth's mantle

    NARCIS (Netherlands)

    Schmalzl, J.T.

    1996-01-01

    The structure of mantle convection will greatly influence the generation and the survival of compositional heterogeneities. Conversely, geochemical observations can be used to obtain information about heterogeneities in the mantle and then, with certain model assumptions, information about the

  9. Feasibility of sequential adjuvant chemotherapy with a 3-month oxaliplatin-based regimen followed by 3 months of capecitabine in patients with stage III and high-risk stage II colorectal cancer: JSWOG-C2 study.

    Science.gov (United States)

    Tsuruta, Atsushi; Yamashita, Kazuki; Tanioka, Hiroaki; Tsuji, Akihito; Inukai, Michio; Yamakawa, Toshiki; Yamatsuji, Tomoki; Yoshimitsu, Masanori; Toyota, Kazuhiro; Yamano, Taketoshi; Nagasaka, Takeshi; Okajima, Masazumi

    2016-01-01

    Six months of oxaliplatin-based chemotherapy is the standard adjuvant chemotherapy for completely resected stage III colorectal cancer (CRC). Also, patients with stage II CRC who are considered to be at high risk of disease recurrence often receive the same adjuvant chemotherapy treatment. We prospectively investigated the extent and degree of neuropathy suffered by stage III and high-risk stage II resectable CRC patients who underwent sequential approach involving 3 months of an oxaliplatin-based regimen followed by 3 months of capecitabine. Patients with completely resected stage III and high-risk stage II CRC aged ≥20 years were eligible. Patients were treated with folinic acid, fluorouracil, and oxaliplatin (FOLFOX) or capecitabine and oxaliplatin (CAPOX) for 3 months followed by capecitabine (2,500 mg/m 2 on days 1-14 every 3 weeks) for 3 months. Primary end points were frequency and the grade of oxaliplatin-induced neurotoxicity as evaluated using the physician-based Common Terminology Criteria for Adverse Events version 4.0 (CTCAE) grading and the patient-based scale, self-reported Patient Neurotoxicity Questionnaire. Ninety-one patients were enrolled and 86 patients assessed. Eighty-four percent of patients completed the planned oxaliplatin-based therapy for 3 months, and 63% of patients completed all treatments for the full 6 months. Overall incidences of grade 3 or 4 peripheral sensory or motor neuropathy according to the CTCAE were 3.5% and 1.2%, respectively. Regarding the peripheral sensory neuropathy, the proportion of Patient Neurotoxicity Questionnaire (grade C-E) and CTCAE (grade 2-4) at months 1.5/3/6 were 11.3/22.1/29.4% and 5.3/4.4/11.3%, respectively (Spearman correlation coefficient: 0.47). A sequential approach to adjuvant chemotherapy with 3 months of an oxaliplatin-based regimen followed by 3 months of capecitabine was tolerated by patients and associated with a low incidence of neuropathy.

  10. Plate Tectonic Cycling and Whole Mantle Convection Modulate Earth's 3He/22Ne Ratio

    Science.gov (United States)

    Dygert, N. J.; Jackson, C.; Hesse, M. A.; Tremblay, M. M.; Shuster, D. L.; Gu, J.

    2016-12-01

    3He and 22Ne are not produced in the mantle or fractionated by partial melting, and neither isotope is recycled back into the mantle by subduction of oceanic basalt or sediment. Thus, it is a surprise that large 3He/22Ne variations exist within the mantle and that the mantle has a net elevated 3He/22Ne ratio compared to volatile-rich planetary precursor materials. Depleted subcontinental lithospheric mantle and mid-ocean ridge basalt (MORB) mantle have distinctly higher 3He/22Ne compared to ocean island basalt (OIB) sources ( 4-12.5 vs. 2.5-4.5, respectively) [1,2]. The low 3He/22Ne of OIBs approaches chondritic ( 1) and solar nebula values ( 1.5). The high 3He/22Ne of the MORB mantle is not similar to solar sources or any known family of meteorites, requiring a mechanism for fractionating He from Ne in the mantle and suggesting isolation of distinct mantle reservoirs throughout geologic time. We model the formation of a MORB source with elevated and variable 3He/22Ne though diffusive exchange between dunite channel-hosted basaltic liquids and harzburgite wallrock beneath mid-ocean ridges. Over timescales relevant to mantle upwelling beneath spreading centers, He may diffuse tens to hundreds of meters into wallrock while Ne is relatively immobile, producing a regassed, depleted mantle lithosphere with elevated 3He/22Ne. Subduction of high 3He/22Ne mantle would generate a MORB source with high 3He/22Ne. Regassed, high 3He/22Ne mantle lithosphere has He concentrations 2-3 orders of magnitude lower than undegassed mantle. To preserve the large volumes of high 3He/22Ne mantle required by the MORB source, mixing between subducted and undegassed mantle reservoirs must have been limited throughout geologic time. Using the new 3He/22Ne constraints, we ran a model similar to [3] to quantify mantle mixing timescales, finding they are on the order of Gyr assuming physically reasonable seafloor spreading rates, and that Earth's convecting mantle has lost >99% of its primordial

  11. Tomography of the upper mantle beneath the African/Iberian collision zone

    Science.gov (United States)

    Mickael, B.; Nolet, G.; Villasenor, A.; Josep, G.; Thomas, C.

    2013-12-01

    During Cenozoic, geodynamics of the western Mediterranean domain has been characterized by a complex history of subduction of Mesozoic oceanic lithosphere. The final stage of these processes is proposed to have led to the development of the Calabria and Gibraltar arcs, whose formation is still under debate. In this study we take advantage of the dense broadband-station networks now available in Alborán Sea region, to develop a high-resolution 3D tomographic P velocity model of the upper mantle beneath the African/Iberian collision zone that will bring new constraints on the past dynamics of this zone. The model is based on 13200 teleseismic arrival times recorded between 2008 and 2012 at 279 stations for which cross-correlation delays are measured with a new technique in different frequency bands centered between 0.03 and 1.0 Hz, and interpreted using multiple frequency tomography. Our model shows, beneath Alborán Sea, a strong (~ 4%) fast vertically dipping anomaly observed to at least 650 km depth. The arched shape of this anomaly and its extent at depth are coherent with a lithospheric slab, thus favoring the hypothesis of a westward consumption of the Ligurian ocean slab by roll-back during Cenozoic. In addition to this fast anomaly in the deep upper-mantle, several high intensity slow anomalies are widely observed in the lithosphere and asthenosphere beneath Morocco and southern Spain. These anomalies are correlated at surface with the position of the orogens (Rif and Atlas) and with Cenozoic volcanic fields. We thus confirm the presence, beneath Morocco, of an anomalous (hot) upper mantle, with piece of evidence for a lateral connection with the Canary volcanic islands, likely indicating a lateral spreading of the Canary plume to the east.

  12. Staging of Lung Cancer

    Science.gov (United States)

    ... LUNG CANCER MINI-SERIES #2 Staging of Lung Cancer Once your lung cancer is diagnosed, staging tells you and your health care provider about ... at it under a microscope. The stages of lung cancer are listed as I, II, III, and IV ...

  13. The evolution of grain mantles and silicate dust growth at high redshift

    Science.gov (United States)

    Ceccarelli, Cecilia; Viti, Serena; Balucani, Nadia; Taquet, Vianney

    2018-05-01

    In dense molecular clouds, interstellar grains are covered by mantles of iced molecules. The formation of the grain mantles has two important consequences: it removes species from the gas phase and promotes the synthesis of new molecules on the grain surfaces. The composition of the mantle is a strong function of the environment that the cloud belongs to. Therefore, clouds in high-zeta galaxies, where conditions - like temperature, metallicity, and cosmic ray flux - are different from those in the Milky Way, will have different grain mantles. In the last years, several authors have suggested that silicate grains might grow by accretion of silicon-bearing species on smaller seeds. This would occur simultaneously with the formation of the iced mantles and be greatly affected by its composition as a function of time. In this work, we present a numerical study of the grain mantle formation in high-zeta galaxies, and we quantitatively address the possibility of silicate growth. We find that the mantle thickness decreases with increasing redshift, from about 120 to 20 layers for z varying from 0 to 8. Furthermore, the mantle composition is also a strong function of the cloud redshift, with the relative importance of CO, CO2, ammonia, methane, and methanol highly varying with z. Finally, being Si-bearing species always a very minor component of the mantle, the formation of silicates in molecular clouds is practically impossible.

  14. Plate tectonics, mantle convection and D'' seismic structures

    Science.gov (United States)

    Wen, Lianxing

    This thesis adopts multidisciplinary (geodynamical and seismological) approaches toward understanding dynamics of the Earth's mantle. My geodynamical approach is directed at understanding the relationship between large-scale surface observables (geoid, topography, plate motions) and mantle rheology and convection of the present-day Earth. In chapter 2, I remove shallow mantle structure of various tectonic features to generate "residual tomography." In chapter 3, I show that the pattern, spectrum and amplitude of the "residual topography" are consistent with shallow origin of the "Earth surface dynamic topography;" the long wavelength geoid and topography (l = 2-3) are successfully explained by density models inferred from the "residual tomography," assuming layered mantle convection stratified at the "920 km seismic discontinuity." In chapter 4, I develop a new method to calculate mantle flow with lateral variation of viscosity. The viscosity contrast between continental and oceanic regions is identified to have dominating effects on both the observed poloidal/toroidal ratio and pattern of toroidal motions at long wavelengths. My seismological approach is focused on exploring fine structures near the core-mantle boundary (CMB) and developing new seismic techniques. I discuss the method development and strategies to explore fine structures in the following chapters. In chapter 5, I develop a hybrid method, a combination of analytical and numerical methods, with numerical methods applied in heterogeneous regions only. In chapter 6, I constrain the general structures of the ultra low velocity zones (ULVZ) near the CMB under the south-east Pacific and Iceland. The SKS-SPdKS data are explained by ULVZ with P-velocity reduction of 10%, horizontal length-scales of about 250 km and height of about 40 km. S-velocity reduction of 30% is consistent with the data. In chapter 7, I constrain the detailed structures of the ULVZ near the CMB from observed broadband PKP precursors

  15. Lower Mantle S-wave Velocity Model under the Western United States

    Science.gov (United States)

    Nelson, P.; Grand, S. P.

    2016-12-01

    Deep mantle plumes created by thermal instabilities at the core-mantle boundary has been an explanation for intraplate volcanism since the 1970's. Recently, broad slow velocity conduits in the lower mantle underneath some hotspots have been observed (French and Romanowicz, 2015), however the direct detection of a classical thin mantle plume using seismic tomography has remained elusive. Herein, we present a seismic tomography technique designed to image a deep mantle plume under the Yellowstone Hotspot located in the western United States utilizing SKS and SKKS waves in conjunction with finite frequency tomography. Synthetic resolution tests show the technique can resolve a 235 km diameter lower mantle plume with a 1.5% Gaussian velocity perturbation even if a realistic amount of random noise is added to the data. The Yellowstone Hotspot presents a unique opportunity to image a thin plume because it is the only hotspot with a purported deep origin that has a large enough aperture and density of seismometers to accurately sample the lower mantle at the length scales required to image a plume. Previous regional tomography studies largely based on S wave data have imaged a cylindrically shaped slow anomaly extending down to 900km under the hotspot, however they could not resolve it any deeper (Schmandt et al., 2010; Obrebski et al., 2010).To test if the anomaly extends deeper, we measured and inverted over 40,000 SKS and SKKS waves' travel times in two frequency bands recorded at 2400+ stations deployed during 2006-2012. Our preliminary model shows narrow slow velocity anomalies in the lower mantle with no fast anomalies. The slow anomalies are offset from the Yellowstone hotspot and may be diapirs rising from the base of the mantle.

  16. Prognostic implication of serum hepatocyte growth factor in stage II/III breast cancer patients who received neoadjuvant chemotherapy.

    Science.gov (United States)

    Kim, Hyori; Youk, Jeonghwan; Yang, Yaewon; Kim, Tae-Yong; Min, Ahrum; Ham, Hye-Seon; Cho, Seongcheol; Lee, Kyung-Hun; Keam, Bhumsuk; Han, Sae-Won; Oh, Do-Youn; Ryu, Han Suk; Han, Wonshik; Park, In Ae; Kim, Tae-You; Noh, Dong-Young; Im, Seock-Ah

    2016-03-01

    In stage II/III breast cancer, neoadjuvant chemotherapy (NAC) is a standard treatment. Although several biomarkers are used to predict prognosis in breast cancer, there is no reliable predictive biomarker for NAC success. Recently, the hepatocyte growth factor (HGF) and cMet signaling pathway demonstrated to be involved in breast cancer tumor progression, and its potential as a biomarker is under active investigation. In this study, we assessed the potential of serum HGF as a prognostic biomarker for NAC efficacy. Venous blood samples were drawn from patients diagnosed with stage II/III breast cancer and treated with NAC in Seoul National University Hospital from August 2004 to November 2009. Serum HGF level was determined using an ELISA system. We reviewed the medical records of the patients and investigated the association of HGF level with patients' clinicopathologic characteristics. A total of 121 female patients (median age = 45 years old) were included. Median level of HGF was 934 pg/ml (lower quartile: 772, upper quartile: 1145 pg/ml). Patients with higher HGF level than median value were significantly more likely to have clinically detectable regional node metastasis (p = 0.017, Fisher's exact test). Patients with complete and partial response according to the American Joint Committee on Cancer 7th Edition criteria tended to have higher HGF level (p = 0.105 by t test). Patients with an HGF level higher than the upper quartile value had longer relapse-free survival than the other patients (106 vs. 85 months, p = 0.008). High serum HGF levels in breast cancer patients are associated with clinically detectable regional node metastasis and, paradoxically, with longer relapse-free survival in stage II/III breast cancer.

  17. Massage Therapy Given by Caregiver in Treating Quality of Life of Young Patients Undergoing Treatment for Cancer

    Science.gov (United States)

    2018-05-24

    Accelerated Phase Chronic Myelogenous Leukemia; Acute Undifferentiated Leukemia; Angioimmunoblastic T-cell Lymphoma; Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative; Blastic Phase Chronic Myelogenous Leukemia; Burkitt Lymphoma; Childhood Acute Lymphoblastic Leukemia in Remission; Childhood Acute Myeloid Leukemia in Remission; Childhood Chronic Myelogenous Leukemia; Childhood Diffuse Large Cell Lymphoma; Childhood Grade III Lymphomatoid Granulomatosis; Childhood Immunoblastic Large Cell Lymphoma; Childhood Myelodysplastic Syndromes; Childhood Nasal Type Extranodal NK/T-cell Lymphoma; Chronic Eosinophilic Leukemia; Chronic Myelomonocytic Leukemia; Chronic Neutrophilic Leukemia; Chronic Phase Chronic Myelogenous Leukemia; Contiguous Stage II Mantle Cell Lymphoma; Cutaneous B-cell Non-Hodgkin Lymphoma; Essential Thrombocythemia; Extramedullary Plasmacytoma; Intraocular Lymphoma; Isolated Plasmacytoma of Bone; Juvenile Myelomonocytic Leukemia; Mast Cell Leukemia; Meningeal Chronic Myelogenous Leukemia; Noncontiguous Stage II Mantle Cell Lymphoma; Polycythemia Vera; Post-transplant Lymphoproliferative Disorder; Primary Myelofibrosis; Primary Systemic Amyloidosis; Progressive Hairy Cell Leukemia, Initial Treatment; Prolymphocytic Leukemia; Recurrent Childhood Acute Lymphoblastic Leukemia; Recurrent Childhood Acute Myeloid Leukemia; Recurrent Childhood Anaplastic Large Cell Lymphoma; Recurrent Childhood Grade III Lymphomatoid Granulomatosis; Recurrent Childhood Large Cell Lymphoma; Recurrent Childhood Lymphoblastic Lymphoma; Recurrent Childhood Small Noncleaved Cell Lymphoma; Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Recurrent/Refractory Childhood Hodgkin Lymphoma; Refractory Chronic Lymphocytic Leukemia; Refractory Hairy Cell Leukemia; Refractory Multiple Myeloma; Relapsing Chronic Myelogenous Leukemia; Secondary Acute Myeloid Leukemia; Stage 0 Chronic Lymphocytic Leukemia; Stage I Childhood Anaplastic Large Cell

  18. Sulfur in Earth's Mantle and Its Behavior During Core Formation

    Science.gov (United States)

    Chabot, Nancy L.; Righter,Kevin

    2006-01-01

    The density of Earth's outer core requires that about 5-10% of the outer core be composed of elements lighter than Fe-Ni; proposed choices for the "light element" component of Earth's core include H, C, O, Si, S, and combinations of these elements [e.g. 1]. Though samples of Earth's core are not available, mantle samples contain elemental signatures left behind from the formation of Earth's core. The abundances of siderophile (metal-loving) elements in Earth's mantle have been used to gain insight into the early accretion and differentiation history of Earth, the process by which the core and mantle formed, and the composition of the core [e.g. 2-4]. Similarly, the abundance of potential light elements in Earth's mantle could also provide constraints on Earth's evolution and core composition. The S abundance in Earth's mantle is 250 ( 50) ppm [5]. It has been suggested that 250 ppm S is too high to be due to equilibrium core formation in a high pressure, high temperature magma ocean on early Earth and that the addition of S to the mantle from the subsequent accretion of a late veneer is consequently required [6]. However, this earlier work of Li and Agee [6] did not parameterize the metalsilicate partitioning behavior of S as a function of thermodynamic variables, limiting the different pressure and temperature conditions during core formation that could be explored. Here, the question of explaining the mantle abundance of S is revisited, through parameterizing existing metal-silicate partitioning data for S and applying the parameterization to core formation in Earth.

  19. Trace elements in olivine of ultramafic lamprophyres controlled by phlogopite-rich mineral assemblages in the mantle source

    Science.gov (United States)

    Veter, Marina; Foley, Stephen F.; Mertz-Kraus, Regina; Groschopf, Nora

    2017-11-01

    Carbonate-rich ultramafic lamprophyres (aillikites) and associated rocks characteristically occur during the early stages of thinning and rifting of cratonic mantle lithosphere, prior to the eruption of melilitites, nephelinites and alkali basalts. It is accepted that they require volatile-rich melting conditions, and the presence of phlogopite and carbonate in the source, but the exact source rock assemblages are debated. Melts similar to carbonate-rich ultramafic lamprophyres (aillikites) have been produced by melting of peridotites in the presence of CO2 and H2O, whereas isotopes and trace elements appear to favor distinct phlogopite-bearing rocks. Olivine macrocrysts in aillikites are usually rounded and abraded, so that it is debated whether they are phenocrysts or mantle xenocrysts. We have analyzed minor and trace element composition in olivines from the type aillikites from Aillik Bay in Labrador, Canada. We characterize five groups of olivines: [1] mantle xenocrysts, [2] the main phenocryst population, and [3] reversely zoned crystals interpreted as phenocrysts from earlier, more fractionated, magma batches, [4] rims on the phenocrysts, which delineate aillikite melt fractionation trends, and [5] rims around the reversely zoned olivines. The main phenocryst population is characterized by mantle-like Ni (averaging 3400 μg g- 1) and Ni/Mg at Mg# of 88-90, overlapping with phenocrysts in ocean island basalts and Mediterranean lamproites. However, they also have low 100 Mn/Fe of 0.9-1.3 and no correlation between Ni and other trace elements (Sc, Co, Li) that would indicate recycled oceanic or continental crust in their sources. The low Mn/Fe without high Ni/Mg, and the high V/Sc (2-5) are inherited from phlogopite in the source that originated by solidification of lamproitic melts at the base of the cratonic lithosphere in a previous stage of igneous activity. The olivine phenocryst compositions are interpreted to result from phlogopite and not high modal

  20. Mantle dynamics in Mars and Venus: Influence of an immobile lithosphere on three-dimensional mantle convection

    International Nuclear Information System (INIS)

    Schubert, G.; Bercovici; Glatzmaier, G.A.

    1990-01-01

    Numerical calculations of fully three-dimensional convection in constant viscosity, compressible spherical shells are interpreted in terms of possible convective motions in the mantles of Venus and Mars. The shells are heated both internally and from below to account for radiogenic heating, secular cooling, and heat flow from the core. The lower boundary of each of the shells is isothermal and shear stress free, as appropriate to the interface between a mantle and a liquid outer core. The upper boundary of each of the shells is rigid and isothermal, as appropriate to the base of a thick immobile lithosphere. Calculations with shear stress-free upper boundaries are also carried out to assess the role of the rigid surface condition. The ratio of the inner radius of each shell to its outer radius is in accordance with possible core sizes in both Venus and Mars. A calculation is also carried out for a Mars model with a small core to simulate mantle convection during early core formation. Different relative proportions of internal and bottom heating are investigated, ranging from nearly complete heating from within to almost all heating from below. The Rayleigh numbers of all the cases are approximately 100 times the critical Rayleigh numbers for the onset of convection. Cylindrical plumes are the prominent form of upwelling in the models independent of the surface boundary condition so long as sufficient heat derives from the core. Thus major volcanic centers on Mars, such as Tharsis and Elysium, and the coronae and some equatorial highlands on Venus may be the surface expressions of cylindrical mantle plumes

  1. Carbonatite and silicate melt metasomatism of the mantle surrounding the Hawaiian plume: Evidence from volatiles, trace elements, and radiogenic isotopes in rejuvenated-stage lavas from Niihau, Hawaii

    Science.gov (United States)

    Dixon, Jacqueline; Clague, David A.; Cousens, Brian; Monsalve, Maria Luisa; Uhl, Jessika

    2008-09-01

    We present new volatile, trace element, and radiogenic isotopic compositions for rejuvenated-stage lavas erupted on Niihau and its submarine northwest flank. Niihau rejuvenated-stage Kiekie Basalt lavas are mildly alkalic and are isotopically similar to, though shifted to higher 87Sr/86Sr and lower 206Pb/204Pb than, rejuvenated-stage lavas erupted on other islands and marginal seafloor settings. Kiekie lavas display trace element heterogeneity greater than that of other rejuvenated-stage lavas, with enrichments in Ba, Sr, and light-rare earth elements resulting in high and highly variable Ba/Th and Sr/Ce. The high Ba/Th lavas are among the least silica-undersaturated of the rejuvenated-stage suite, implying that the greatest enrichments are associated with the largest extents of melting. Kiekie lavas also have high and variable H2O/Ce and Cl/La, up to 620 and 39, respectively. We model the trace element concentrations of most rejuvenated-stage lavas by small degrees (˜1% to 9%) of melting of depleted peridotite recently metasomatized by a few percent of an enriched incipient melt (0.5% melting) of the Hawaiian plume. Kiekie lavas are best explained by 4% to 13% partial melting of a peridotite source metasomatized by up to 0.2% carbonatite, similar in composition to oceanic carbonatites from the Canary and Cape Verde Islands, with lower proportion of incipient melt than that for other rejuvenated-stage lavas. Primary H2O and Cl of the carbonatite component must be high, but variability in the volatile data may be caused by heterogeneity in the carbonatite composition and/or interaction with seawater. Our model is consistent with predictions based on carbonated eclogite and peridotite melting experiments in which (1) carbonated eclogite and peridotite within the Hawaiian plume are the first to melt during plume ascent; (2) carbonatite melt metasomatizes plume and surrounding depleted peridotite; (3) as the plume rises, silica-undersaturated silicate melts are also

  2. Mapping the extent of disease by multislice computed tomography, magnetic resonance imaging and sentinel node evaluation in stage I and II cervical carcinoma

    Directory of Open Access Journals (Sweden)

    Rajaram S

    2010-01-01

    Full Text Available Aims: (1 To map the extent of disease in women with stage I and II carcinoma cervix by multislice spiral computed tomography (CT, magnetic resonance imaging (MRI and sentinel nodes. (2 To assess accuracy of each modality individually and in conjunction with FIGO clinical staging. Design and Setting: Prospective, single-blind study. Departments of Obstetrics and Gynaecology, Radiodiagnosis, and Pathology, UCMS and GTBH and Division of Radiological Imaging and Bioinformatics, INMAS, Delhi. Material and Method: The study was conducted on 25 women with cervical cancer FIGO stage I and II. Each woman underwent clinical staging, multislice spiral CT and MRI which was compared to the gold-standard histopathology/cytology. The overall accuracy of each modality and improvement of clinical staging by CT/MRI were noted. Sentinel nodes were evaluated by intracervical Patent Blue V dye injection. Statistical Analysis: Sensitivity, specificity, positive and negative predictive values were calculated by 2Χ2 contingency tables. Results: The accuracy of staging by FIGO, CT and MRI was 68%, 52% and 80%, respectively. MRI and CT improved the overall accuracy of FIGO staging to 96% and 80%, respectively. Sentinel nodes were identified in 89% of patients with 91% accuracy. Conclusion: MRI emerges as the most valuable stand-alone modality improving accuracy of FIGO staging to 96%. Sentinel lymph-node evaluation appears promising in evaluating spread beyond cervix.

  3. Organ preservation in stage II and III head and neck cancer utilizing alternate week concomitant chemoradiotherapy

    International Nuclear Information System (INIS)

    Mansur, David B.; Vokes, Everett; Mittal, Bharat B.; Stenson, Kerstin; Kies, M.; Pelzer, H.; Nautiyal, Jaishanker; Kozloff, Mark; Weichselbaum, Ralph R.; Haraf, Daniel J.

    1996-01-01

    Purpose: A prospective phase II trial was conducted to determine the efficacy and rate of organ preservation of alternate week concomitant chemoradiotherapy in stage II and III head and neck cancer. Methods: Forty-nine patients (10 stage II and 39 stage III) with squamous cell carcinoma of the head and neck region have been entered into a prospective phase II trial. Pretreatment evaluation included history and physical examination, computed tomography of the neck, bone scan, chest x-ray, panendoscopy and biopsy confirmation of malignancy. Therapy is given in 2 week cycles consisting of 5 days of concomitant chemoradiotherapy followed by a nine day break during which no treatment is given. Each cycle of treatment consists of 1.0 gm hydroxyurea P.O. every 12 hours for 6 days (11 doses per cycle) and 800mg/m 2 /d continuous infusion 5-fluorouracil along with concomitant radiation therapy (RT) administered in 1.8-2.0 Gy daily fractions for five days. This alternate week (week on/week off) schedule is continued for a total of 7 cycles resulting in an overall treatment time of 13 weeks and a total RT dose of 70 Gy. Extent of initial surgery included biopsy only (59.2%), minimal laser debulking (12.2%), and resection with or without neck dissection (28.6%). Results: The majority of patients are male (71.4%), with a median age of 61.3 years. Primary sites included oral cavity (16.3%), oropharynx (12.2%), larynx (57.1%), hypopharynx (8.1%), and nasopharynx (4.1%). T stage included T3 (32 patients, 65.3%), T2 (16 patients, 32.7%), and T1 (1 patient). N stage included N1 (17 patients, 34.7%), and N0 (32 patients, 65.3%). With a median follow-up of 27 months, the overall response rate is 100% (91.7 complete response, and 8.3% partial response). The 5 year actuarial local control, disease free survival, and overall survival is 90.1%, 88.3%, and 65.0%, respectively. One patient has failed with distant disease alone. Four patients had isolated local failures and (3(4)) were

  4. Prognostic significance of the PC10 index for patients with stage II and III oesophageal cancer treated with radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sugahara, Shinji; Irie, Toshiyuki; Nozawa, Kumiko; Nakajima, Kotaro [Hitachi General Hospital, Ibaraki (Japan). Dept. of Radiology; Ohara, Kiyoshi; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Dept. of Radiology; Takahashi, Atsushi [Hitachi General Hospital, Ibaraki (Japan). Dept. of Pathology; Watanabe, Teruo [Tsukuba Univ., Ibaraki (Japan). Dept. of Pathology; Tanaka, Naomi [Tsukuba Univ., Ibaraki (Japan). Dept. of Internal Medicine

    1999-07-01

    The monoclonal antibody PC10 is used for immunohistochemical staining of the proliferating cell nuclear antigen (PCNA). The percentage of PC10-positive cancer cells is defined as the PC10 index. We evaluated the relationship between the PC10 index in pretreatment endoscopic biopsies and the prognoses of 47 patients with Stage II-III oesophageal squamous cell carcinoma treated with radiotherapy. The patients with a PC10 index >40% had significantly poorer prognoses than the other patients (p=0.0007). Proportional hazards model analysis indicated that only the PC10 index was a prognostic factor (p=0.0009). The patient group of complete responders showed significantly lower PC10 indices compared to patients with a partial response or no change (p=0.049). The PC10 index can be a good predictive indicator of the prognosis in patients with Stage II-III oesophageal cancer treated with radiotherapy. (orig.)

  5. Constraining Mantle Differentiation Processes with La-Ce and Sm-Nd Isotope Systematics

    Science.gov (United States)

    Willig, M.; Stracke, A.

    2016-12-01

    Cerium (Ce) and Neodymium (Nd) isotopic ratios in oceanic basalts reflect the time integrated La-Ce and Sm-Nd ratios, and hence the extent of light rare earth element element (LREE) depletion or enrichment of their mantle sources. New high precision Ce-Nd isotope data from several ocean islands define a tight array in ԑCe-ԑNd space with ԑNd = -8.2±0.4 ԑCe + 1.3±0.9 (S.D.), in good agreement with previous data [1, 2]. The slope of the ԑCe-ԑNd array and the overall isotopic range are sensitive indicators of the processes that govern the evolution of the mantle's LREE composition. A Monte Carlo approach is employed to simulate continuous mantle-crust differentiation by partial melting and recycling of crustal materials. Partial melting of mantle peridotites produces variably depleted mantle and oceanic crust, which evolve for different time periods, before the oceanic crust is recycled back into the mantle including small amounts of continental crust (GLOSS [3]). Subsequently, depleted mantle and recycled materials of variable age and composition melt, and the respective melts mix in different proportions. Mixing lines strongly curve towards depleted mantle, and tend to be offset from the data for increasingly older and more depleted mantle. Observed ԑCe-ԑNd in ridge [1] and ocean island basalts and the slope of the ԑCe-ԑNd array therefore define upper limits for the extent and age of LREE depletion preserved in mantle peridotites. Very old average mantle depletion ages (> ca. 1-2 Ga) for the bulk of the mantle are difficult to reconcile with the existing ԑCe-ԑNd data, consistent with the range of Nd-Hf-Os model ages in abyssal peridotites [4-6]. Moreover, unless small amounts of continental crust are included in the recycled material, it is difficult to reproduce the relatively shallow slope of the ԑCe-ԑNd array, consistent with constraints from the ԑNd - ԑHf mantle array [7]. [1] Makishima and Masuda, 1994 Chem. Geol. 118, 1-8. [2] Doucelance et al

  6. Elasticity of superhydrous phase B at the mantle temperature and pressure: Implications for 800-km discontinuity and water flow into lower mantle

    Science.gov (United States)

    Yang, D.; Wang, W.; Wu, Z.

    2017-12-01

    Plate subduction can transport the water to the Earth's interior by forming hydrous phases and water can exert important effects on global dynamics and many processes within the deep Earth. Superhydrous phase B (ShyB), as an important candidate for transporting water into the mantle transition zone and lower mantle, is stable up to 31 GPa and will decompose into bridgmanite, periclase and water at a depth of 800 km [Komabayashi and Omori, 2006]. The decomposition of ShyB may be related to the seismic discontinuity at the depth of 800 km in Western-Pacific Subduction Zones [Liu et al., 2016; Porritt and Yoshioka, 2016]. The detail discussions on this topic require the elasticity of ShyB at the P-T conditions of the transition zone and lower mantle. In this contribution, we obtained the thermal elasticity of ShyB using first-principles calculations. ShyB shows a very low velocity and density compared to the bridgmanite and periclase, the major minerals in the lower mantle. The accumulation of ShyB will generate the low-velocity anomaly in the uppermost lower mantle. The dehydration of ShyB will cause the Vp, Vs, and density increase by 7.5%, 15.0% and 12%, respectively. It means that a slab with 10% ShyB could cause an impedance contrast of 2.7% at a depth of 800 km for shear wave. Furthermore, the released waters by the dehydration of ShyB probably migrate upward and promote the partial melt to reduce the sound velocity at shallower depth, which can further explain the low-velocity zones just above 800-km discontinuity in Western-Pacific Subduction Zones [Liu et al., 2016]. Komabayashi, T., and S. Omori (2006), Internally consistent thermodynamic data set for dense hydrous magnesium silicates up to 35GPa, 1600°C: Implications for water circulation in the Earth's deep mantle, Physics of the Earth and Planetary Interiors, 156(1-2), 89-107. Liu, Z., J. Park, and S. I. Karato (2016), Seismological detection of low-velocity anomalies surrounding the mantle transition

  7. A reconnaissance view of tungsten reservoirs in some crustal and mantle rocks: Implications for interpreting W isotopic compositions and crust-mantle W cycling

    Science.gov (United States)

    Liu, Jingao; Pearson, D. Graham; Chacko, Thomas; Luo, Yan

    2018-02-01

    High-precision measurements of W isotopic ratios have enabled increased exploration of early Earth processes. However, when applying W isotopic data to understand the geological processes, it is critical to recognize the potential mobility of W and hence evaluate whether measured W contents and isotopic compositions reflect the primary petrogenetic processes or instead are influenced by the effects of secondary inputs/mobility. Furthermore, if we are to better understand how W is partitioned between different minerals during melting and metasomatic processes it is important to document the likely sinks for W during these processes. In addition, an understanding of the main hosts for W in the crust and mantle is critically important to constrain how W is cycled and stored in the crust-mantle geochemical cycle. As a first step to investigate these issues, we have carried out in situ concentration measurements of W and other HFSEs in mineral phases within a broad spectrum of crustal and mantle rocks, along with whole-rock concentration measurements. Mass balance shows that for tonalitic gneiss and amphibolite, the major rock-forming minerals can adequately account for the bulk W budget, and for the pristine ultramafic rocks, olivine and orthopyroxene are the major controlling phases for W whereas for metasomatized ultramafic rocks, significant W is hosted in Ti-bearing trace phases (e.g., rutile, lindsleyite) along grain boundaries or is inferred to reside in cryptic W-bearing trace phases. Formation or decomposition of these phases during secondary processes could cause fractionation of W from other HFSEs, and also dramatically modify bulk W concentrations in rocks. For rocks that experienced subsequent W enrichment/alteration, their W isotopic compositions may not necessarily represent their mantle sources, but could reflect later inputs. The relatively small suite of rocks analyzed here serves as a reconnaissance study but allows some preliminary speculations on

  8. Tomographic and Geodynamic Constraints on Convection-Induced Mixing in Earth's Deep Mantle

    Science.gov (United States)

    Hafter, D. P.; Forte, A. M.; Bremner, P. M.; Glisovic, P.

    2017-12-01

    Seismological studies reveal two large low-shear-velocity provinces (LLSVPs) in the lowermost mantle (e.g., Su et al. 1994; Wang & Wen 2007; He & Wen 2012), which may represent accumulations of subducted slabs at the CMB (Tan & Gurnis 2005; Christensen & Hoffman 1994) or primordial material generated in the early differentiation of Earth (e.g. Li et al. 2014). The longevity or stability of these large-scale heterogeneities in the deep mantle depends on the vigor and spatial distribution of the convective circulation, which is in turn dependent on the distribution of mantle buoyancy and viscosity (e.g. Glisovic & Forte 2015). Here we explore the state of convective mixing in the mantle using the ASPECT convection code (Kronbichler et al. 2012). A series of experiments are conducted to consider the geochemical and dynamical contributions of LLSVPs to deep-mantle upwellings and corresponding plume-sourced volcanism. The principal feature of these experiments is the use of particle tracers to track geochemical changes in the LLSVPs and mantle plumes in addition to identifying those parts of the mantle that may remain unmixed. We employ 3-D mantle density anomalies derived from joint inversions of seismic, geodynamic and mineral physics constraints and geodynamically-constrained viscosity distributions (Glisovic et al. 2015) to ensure that the predicted flow fields yield a good match to key geophysical constraints (e.g. heat flow, global gravity anomalies and plate velocities).

  9. Density heterogeneity of the North American upper mantle from satellite gravity and a regional crustal model

    DEFF Research Database (Denmark)

    Herceg, Matija; Artemieva, Irina; Thybo, Hans

    2014-01-01

    -density conversion and (ii) uncertainties in knowledge of the crustal structure (thickness and average Vp velocities of individual crustal layers, including the sedimentary cover). In this study, we address both sources of possible uncertainties by applying different conversions from velocity to density...... and by introducing variations into the crustal structure which corresponds to the uncertainty of its resolution by highquality and low-quality seismic models. We examine the propagation of these uncertainties into determinations of lithospheric mantle density. Given a relatively small range of expected density...

  10. Phase I (or phase II) dose-ranging clinical trials: proposal of a two-stage Bayesian design.

    Science.gov (United States)

    Zohar, Sarah; Chevret, Sylvie

    2003-02-01

    We propose a new design for phase I (or phase II) dose-ranging clinical trials aiming at determining a dose of an experimental treatment to satisfy safety (respectively efficacy) requirements, at treating a sufficiently large number of patients to estimate the toxicity (respectively failure) probability of the dose level with a given reliability, and at stopping the trial early if it is likely that no dose is safe (respectively efficacious). A two-stage design was derived from the Continual Reassessment Method (CRM), with implementation of Bayesian criteria to generate stopping rules. A simulation study was conducted to compare the operating characteristics of the proposed two-stage design to those reached by the traditional CRM. Finally, two applications to real data sets are provided.

  11. Effects of mantle rheologies on viscous heating induced by glacial isostatic adjustment

    NARCIS (Netherlands)

    Huang, Ping Ping; Wu, Patrick; van der Wal, W.

    2018-01-01

    It has been argued that viscous dissipation from mantle flow in response to surface loading during glacial cycles can result in short-term heating and thus trigger transient volcanism or changes in mantle properties, which may in turn affect mantle dynamics. Furthermore, heating near the Earth's

  12. Beyond low-level activity: On a 'non-radioactive' gas mantle

    Energy Technology Data Exchange (ETDEWEB)

    Poljanc, Karin [Atominstitut der Osterreichischen Universitaeten, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria); Steinhauser, Georg [Atominstitut der Osterreichischen Universitaeten, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria)]. E-mail: georg.steinhauser@ati.ac.at; Sterba, Johannes H. [Atominstitut der Osterreichischen Universitaeten, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria); Buchtela, Karl [Atominstitut der Osterreichischen Universitaeten, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria); Bichler, Max [Atominstitut der Osterreichischen Universitaeten, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria)

    2007-03-01

    Gas mantles for camping gas lanterns sometimes contain thorium compounds. During the last years, the use of thorium-free gas mantles has become more and more popular due to the avoidance of a radioactive heavy metal. We investigated a gas mantle type that is declared to be 'non-radioactive' and that can be bought in Austria at the moment. Methods used were Instrumental Neutron Activation Analysis (INAA), {gamma}-spectroscopy, and Liquid Scintillation Counting (LSC). We found massive thorium contents of up to 259 mg per gas mantle. Leaching experiments showed that only 0.4% of the Th but approximately 90% of the decay products of {sup 232}Th can be leached under conditions simulating sucking and chewing with human saliva. In this paper, the investigation of these gas mantles including the consideration of the environmental hazard caused by disposed mantles and the health hazard for unsuspecting consumers is presented and legal consequences are discussed for this fraud.

  13. BurnMan: A lower mantle mineral physics toolkit

    KAUST Repository

    Cottaar, Sanne; Heister, Timo; Rose, Ian; Unterborn, Cayman

    2014-01-01

    We present BurnMan, an open-source mineral physics toolbox to determine elastic properties for specified compositions in the lower mantle by solving an Equation of State (EoS). The toolbox, written in Python, can be used to evaluate seismic velocities of new mineral physics data or geodynamic models, and as the forward model in inversions for mantle composition. The user can define the composition from a list of minerals provided for the lower mantle or easily include their own. BurnMan provides choices in methodology, both for the EoS and for the multiphase averaging scheme. The results can be visually or quantitatively compared to observed seismic models. Example user scripts show how to go through these steps. This paper includes several examples realized with BurnMan: First, we benchmark the computations to check for correctness. Second, we exemplify two pitfalls in EoS modeling: using a different EoS than the one used to derive the mineral physical parameters or using an incorrect averaging scheme. Both pitfalls have led to incorrect conclusions on lower mantle composition and temperature in the literature. We further illustrate that fitting elastic velocities separately or jointly leads to different Mg/Si ratios for the lower mantle. However, we find that, within mineral physical uncertainties, a pyrolitic composition can match PREM very well. Finally, we find that uncertainties on specific input parameters result in a considerable amount of variation in both magnitude and gradient of the seismic velocities. © 2014. American Geophysical Union. All Rights Reserved.

  14. BurnMan: A lower mantle mineral physics toolkit

    KAUST Repository

    Cottaar, Sanne

    2014-04-01

    We present BurnMan, an open-source mineral physics toolbox to determine elastic properties for specified compositions in the lower mantle by solving an Equation of State (EoS). The toolbox, written in Python, can be used to evaluate seismic velocities of new mineral physics data or geodynamic models, and as the forward model in inversions for mantle composition. The user can define the composition from a list of minerals provided for the lower mantle or easily include their own. BurnMan provides choices in methodology, both for the EoS and for the multiphase averaging scheme. The results can be visually or quantitatively compared to observed seismic models. Example user scripts show how to go through these steps. This paper includes several examples realized with BurnMan: First, we benchmark the computations to check for correctness. Second, we exemplify two pitfalls in EoS modeling: using a different EoS than the one used to derive the mineral physical parameters or using an incorrect averaging scheme. Both pitfalls have led to incorrect conclusions on lower mantle composition and temperature in the literature. We further illustrate that fitting elastic velocities separately or jointly leads to different Mg/Si ratios for the lower mantle. However, we find that, within mineral physical uncertainties, a pyrolitic composition can match PREM very well. Finally, we find that uncertainties on specific input parameters result in a considerable amount of variation in both magnitude and gradient of the seismic velocities. © 2014. American Geophysical Union. All Rights Reserved.

  15. A systematic review and meta-analysis of the safety, feasibility and effect of exercise in women with stage II+ breast cancer.

    Science.gov (United States)

    Singh, Ben; Spence, Rosalind R; Steele, Megan L; Sandler, Carolina X; Peake, Jonathan M; Hayes, Sandra C

    2018-05-03

    To systematically evaluate the safety, feasibility and effect of exercise among women with stage II+ breast cancer. CINAHL, Cochrane, Ebscohost, MEDLINE, Pubmed, ProQuest Health and Medical Complete, ProQuest Nursing and Allied Health Source, Science Direct and SPORTDiscus were searched for articles published prior to March 1, 2017. Randomised, controlled, exercise trials involving at least 50% of women diagnosed with stage II+ breast cancer were included. Risk of bias was assessed and adverse event severity was classified using the Common Terminology Criteria. Feasibility was evaluated by computing median (range) recruitment, withdrawal and adherence rates. Meta-analyses were performed to evaluate exercise safety and effects on health outcomes only. The influence of intervention characteristics (mode, supervision, duration and timing) on exercise outcomes were also explored. There were no differences in adverse events between exercise and usual care (risk difference: feasibility outcomes were similar, irrespective of exercise mode, supervision, duration, or timing. Effects of exercise for quality of life, fitness, fatigue, strength, anxiety, depression, body mass index and waist circumference compared with usual care were significant (standardised mean difference range: 0.17-0.77, pfeasibility and effects of exercise for those with stage II+ breast cancer, suggesting that national and international exercise guidelines appear generalizable to women with local, regional and distant breast cancer. Copyright © 2018. Published by Elsevier Inc.

  16. Social Development Training Project. Stage I and Stage II. [The Granville Project].

    Science.gov (United States)

    Riches, Vivienne C., Ed.

    The book presents a training program developed at the Granville Work Preparation Centre in Australia, to teach mildly retarded adolescents basic social skills and competencies. The program is divided into two stages, with a total of 17 different skill areas. Stage 1 covers self-awareness, social/interpersonal skills, relaxation and behavioral self…

  17. Experimental investigation of flow-induced fabrics in rocks at upper-mantle pressures: Application to understanding mantle dynamics and seismic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Kohlstedt, David L. [Univ. of Minnesota, Minneapolis, MN (United States)

    2016-04-26

    The goal of this collaborative research effort between W.B. Durham at the Massachusetts Institute of Technology (MIT) and D.L. Kohlstedt and S. Mei at the University of Minnesota (UMN) was to exploit a newly developed technology for high-pressure, high-temperature deformation experimentation, namely, the deformation DIA (D-DIA) to determine the deformation behavior of a number of important upper mantle rock types including olivine, garnet, enstatite, and periclase. Experiments were carried out under both hydrous and anhydrous conditions and at both lithospheric and asthenospheric stress and temperature conditions. The result was a group of flow laws for Earth’s upper mantle that quantitatively describe the viscosity of mantle rocks from shallow depths (the lithosphere) to great depths (the asthenosphere). These flow laws are fundamental for modeling the geodynamic behavior and heat transport from depth to Earth’s surface.

  18. Experimental investigation of flow-induced fabrics in rocks at upper-mantle pressures. Application to understanding mantle dynamics and seismic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Durham, William B. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2016-05-02

    The goal of this collaborative research effort between W.B. Durham at the Massachusetts Institute of Technology (MIT) and D.L. Kohlstedt and S. Mei at the University of Minnesota (UMN) was to exploit a newly developed technology for high-pressure, high-temperature deformation experimentation, namely, the deformation DIA (D-DIA), to determine the deformation behavior of a number of important upper mantle rock types including olivine, garnet, enstatite, and periclase. Experiments were carried out under both hydrous and anhydrous conditions and at both lithospheric and asthenospheric stress and temperature conditions. The result was a group of flow laws for Earth’s upper mantle that quantitatively describe the viscosity of mantle rocks from shallow depths (the lithosphere) to great depths (the asthenosphere). These flow laws are fundamental for modeling the geodynamic behavior and heat transport from depth to Earth’s surface.-

  19. Lateral column lengthening for acquired adult flatfoot deformity caused by posterior tibial tendon dysfunction stage II: a retrospective comparison of calcaneus osteotomy with calcaneocuboid distraction arthrodesis.

    Science.gov (United States)

    Haeseker, Guus A; Mureau, Marc A; Faber, Frank W M

    2010-01-01

    In this study, clinical and radiological results after lateral column lengthening by calcaneocuboid distraction arthrodesis and calcaneus osteotomy were compared. Thirty-three patients (35 feet) treated with lateral column lengthening by distraction arthrodesis (14 patients, 16 feet; group I) or by calcaneus osteotomy (19 patients, 19 feet; group II) for adult-acquired flatfoot deformity caused by stage II posterior tibial tendon dysfunction were compared retrospectively. Mean follow-up was 42.4 months (range, 6-78 months) for group I and 15.8 months (range, 6-32 months) for group II (P lengthening by means of calcaneus osteotomy rather than distraction arthrodesis of the calcaneocuboid joint, for correction of stage II posterior tibial tendon dysfunction. Copyright 2010 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Dehydration of δ-AlOOH in the lower mantle

    Science.gov (United States)

    Piet, H.; Shim, S. H.; Tappan, J.; Leinenweber, K. D.; Greenberg, E.; Prakapenka, V. B.

    2017-12-01

    Hydrous phase δ-AlOOH is an important candidate for water transport and storage in the Earth's deep mantle [1]. Knowing the conditions, under which it is stable and dehydrated, is therefore important for understanding the water transportation to the deep mantle or even to the core. A few experimental studies [1, 2] have shown that δ-AlOOH may be stable in cold descending slabs while it is dehydrated into a mixture of corundum and water under normal mantle conditions, up to 25 GPa. A subsequent study [3] reported the stability of δ-AlOOH in cold descending slabs to the core-mantle boundary conditions (2300 K at 135 GPa). However, the dehydration of δ-AlOOH has not bee directly observed in the experiments conducted at pressures above 25 GPa. We have synthesized δ-AlOOH from diaspore and Al(OH)3 in multi-anvil press at ASU. The sample was mixed with Au for coupling with near IR laser beams and loaded in diamond-anvil cells. We performed the laser-heated diamond anvil cell experiments at the 13IDD beamline of the Advanced Photon Source and ASU. At APS, we measured X-ray diffraction patterns at in situ high pressure and temperature. We observed the appearance of the corundum diffraction lines at 1700-2000 K and 55-90 GPa, indicating the dehydration of δ-AlOOH to Al2O3+ H2O. We found that the transition occurs over a broad range of temperature (500 K). We also observed that the dehydration of δ-AlOOH was accompanied by sudden change in laser coupling, most likely due to the release of fluids. The property change also helps us to determine the dehydration at ASU without in situ XRD. Our new experimental results indicate that δ-AlOOH would be stable in most subducting slabs in the deep mantle. However, because the dehydration occurs very close to the temperatures expected for the lower mantle, its stability is uncertain in the normal mantle. [1] Ohtani et al. 2001, Stability field of new hydrous phase, delta-AlOOH, Geophysical Research Letters 28, 3991-3993. [2

  1. Could semiquantitative FDG analysis add information to the prognosis in patients with stage II/III breast cancer undergoing neoadjuvant treatment?

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista, Laura; Cervino, Anna Rita [Veneto Institute of Oncology IOV - IRCCS, Radiotherapy and Nuclear Medicine Unit, Padua (Italy); Ghiotto, Cristina; Guarneri, Valentina; Conte, Pierfranco [Veneto Institute of Oncology IOV - IRCCS, Medical Oncology 2 Unit, Padua (Italy); Saibene, Tania; Michieletto, Silvia; Fernando, Bozza [Veneto Institute of Oncology IOV - IRCCS, Breast Unit, Padua (Italy); Orvieto, Enrico [University Hospital of Padua, Department of Pathology, Padua (Italy)

    2015-10-15

    We investigated whether maximum standardized uptake value (SUVmax), metabolic tumour volume (MTV), total lesion glycolysis (TLG) and whole-body (WB) SUVmax, WB MTV and WB TLG measured by {sup 18}F-FDG PET/CT could improve prognostic stratification in patients with stage II/III breast cancer (BC). We prospectively enrolled 99 consecutive women (median age 50 years, range 27 - 77 years) with pathologically proven stage II/III BC who underwent pretreatment FDG PET/CT. WB SUVmax, WB MTV and WB TLG were measured in all malignant lesions. Survival was analysed using the Kaplan-Meier method. Cox proportional hazards models were constructed to test for relationships among WB SUVmax, WB MTV, WB TLG, and overall survival (OS) and disease-free survival (DFS), after adjustment for age, and histopathological and immunohistochemical features (oestrogen/progesterone and HER2 expression, proliferation index and grade). The median values of WB SUVmax, WB MTV and WB TLG were 16.2 (range 1.5 - 33.1), 14 cm{sup 3} (range 0.03 - 708.6 cm{sup 3}) and 62.5 (0.06 - 3869.4), respectively. All WB semiquantitative values were higher in patients with higher TNM stage, although not significantly (all p > 0.05). The median follow-up for surviving patients was 30 months, with a range of 13 - 45 months. Both PFS and OS of patients with low WB SUVmax, WB MTV and WB TLG were longer than that of patients with high WB values for progression, although not statistically significant. However, stratifying the patients in accordance with the stage of disease, both PFS and OS were significantly lower in patients with high WB TLG and stage III than in patients with stage II (p < 0.05). In multivariate analyses, WB MTV and WB TLG were independent prognostic factors for PFS (hazard ratio 1.004, 95 % confidence interval 1.002 - 1.006, p < 0.001, and hazard ratio 1.001, 95 % confidence interval 1.000 - 1.001, p = 0.011, respectively). The addition of WB TLG to clinical data may provide a more detailed

  2. Preservation of an Archaean whole rock Re-Os isochron for the Venetia lithospheric mantle: Evidence for rapid crustal recycling and lithosphere stabilisation at 3.3 Ga

    Science.gov (United States)

    van der Meer, Quinten H. A.; Klaver, Martijn; Reisberg, Laurie; Riches, Amy J. V.; Davies, Gareth R.

    2017-11-01

    Re-Os and platinum group element analyses are reported for peridotite xenoliths from the 533 Ma Venetia kimberlite cluster situated in the Limpopo Mobile Belt, the Neoarchaean collision zone between the Kaapvaal and Zimbabwe Cratons. The Venetian xenoliths provide a rare opportunity to examine the state of the cratonic lithosphere prior to major regional metasomatic disturbance of Re-Os systematics throughout the Phanerozoic. The 32 studied xenoliths record Si-enrichment that is characteristic of the Kaapvaal lithospheric mantle and can be subdivided into five groups based on Re-Os analyses. The most pristine group I samples (n = 13) display an approximately isochronous relationship and fall on a 3.28 ± 0.17 Ga (95 % conf. int.) reference line that is based on their mean TMA age. This age overlaps with the formation age of the Limpopo crust at 3.35-3.28 Ga. The group I samples derive from ∼50 to ∼170 km depth, suggesting coeval melt depletion of the majority of the Venetia lithospheric mantle column. Group II and III samples have elevated Re/Os due to Re addition during kimberlite magmatism. Group II has otherwise undergone a similar evolution as the group I samples with overlapping 187Os/188Os at eruption age: 187Os/188OsEA, while group III samples have low Os concentrations, unradiogenic 187Os/188OsEA and were effectively Re-free prior to kimberlite magmatism. The other sample groups (IV and V) have disturbed Re-Os systematics and provide no reliable age information. A strong positive correlation is recorded between Os and Re concentrations for group I samples, which is extended to groups II and III after correction for kimberlite addition. This positive correlation precludes a single stage melt depletion history and indicates coupled remobilisation of Re and Os. The combination of Re-Os mobility, preservation of the isochronous relationship, correlation of 187Os/188Os with degree of melt depletion and lack of radiogenic Os addition puts tight constraints on

  3. Gastric and colonic mantle cell lymphoma - incidental discovery.

    Science.gov (United States)

    Pitigoi, Dan; Stoica, Victor; Stoia, Razvan; Dobrea, Camelia; Becheanu, Gabriel; Diculescu, Mircea

    2009-03-01

    A 65-year old patient, with no medical history, was admitted for lower gastrointestinal bleeding. On clinical examination the patient seemed to be in good health. However the examination was completed with a rectosigmoidoscopy revealing the presence of mucosal erosions, ulcerations, multiple papulae. The histopathological examination raised the suspicion of a colonic lymphoma. Gastric biopsies suggested a gastric MALT type lymphoma associated to the colonic lymphoma, but the immunohistochemical profile corresponded to a mantle cell lymphoma. In spite of the general poor prognosis of mantle cell lymphoma, our patient had a good clinical and endoscopic response to the standard cyclophosphamide, vincristine, prednisone (CVP) therapy. The cases of gastric and colonic mantle lymphoma are rare, the response to therapy is poor; fortunately, our patient had a complete resolution after completion of the six cycles of chemotherapy.

  4. [The mantle zone in lymphatic follicles and its stratification].

    Science.gov (United States)

    Bednár, B

    1993-04-01

    Ten inguinal lymph nodes and spleens from autopsies were chosen according to age decades in order to get an idea about usual appearance of follicular structures. The group was complemented by 4 palatine tonsils from routine biopsies. Phenotype was ascertained by using about 30 standard markers and results were compared with a basic histocytological picture. The appearance of lymphatic tissue was quite different according to location and age categories, nevertheless, there were common immunophenotypic and structural features of follicular mantle in younger persons. It mostly comprised four cellular layers, more conspicuous at the upper pole of the follicle. An innermost layer was small-celled blastic, MB 2 and IgD positive, the next B monocytoid layer had medium sized cells of a similar phenotype but more alc, phosphatase positive. An inconstant plasmacytoid layer and a clarocellular layer used to be incomplete. It was cytostructurally characteristic but immunohistologically non-standard (faint CD 19 et CD 20 positivity). T 4 lymphocytes and perhaps some other elements leaving germinal centres were admixed into the inner mantle layer. Various small lymphoid cells, especially T 8 lymphocytes and sometimes litoral cells, were admixed into mantle periphery. Mutual exchange of lymphatic cells between the germinal and mantle zones was very scant. The mantle zone is presumed therefore to be independent from the structural and functional point of view as well.

  5. Deep and persistent melt layer in the Archaean mantle

    Science.gov (United States)

    Andrault, Denis; Pesce, Giacomo; Manthilake, Geeth; Monteux, Julien; Bolfan-Casanova, Nathalie; Chantel, Julien; Novella, Davide; Guignot, Nicolas; King, Andrew; Itié, Jean-Paul; Hennet, Louis

    2018-02-01

    The transition from the Archaean to the Proterozoic eon ended a period of great instability at the Earth's surface. The origin of this transition could be a change in the dynamic regime of the Earth's interior. Here we use laboratory experiments to investigate the solidus of samples representative of the Archaean upper mantle. Our two complementary in situ measurements of the melting curve reveal a solidus that is 200-250 K lower than previously reported at depths higher than about 100 km. Such a lower solidus temperature makes partial melting today easier than previously thought, particularly in the presence of volatiles (H2O and CO2). A lower solidus could also account for the early high production of melts such as komatiites. For an Archaean mantle that was 200-300 K hotter than today, significant melting is expected at depths from 100-150 km to more than 400 km. Thus, a persistent layer of melt may have existed in the Archaean upper mantle. This shell of molten material may have progressively disappeared because of secular cooling of the mantle. Crystallization would have increased the upper mantle viscosity and could have enhanced mechanical coupling between the lithosphere and the asthenosphere. Such a change might explain the transition from surface dynamics dominated by a stagnant lid on the early Earth to modern-like plate tectonics with deep slab subduction.

  6. Deep Subducction in a Compressible Mantle: Observations and Theory

    Science.gov (United States)

    King, S. D.

    2017-12-01

    Our understanding of slab dynamics is primarily based on the results of numerical models of subduction. In such models coherent, cold slabs are clearly visible from the surface of the Earth to the core mantle boundary. In contrast, fast seismic anomalies associated with cold subducted slabs are difficult to identify below 1500-2000 km in tomographic models of Earth's mantle. One explanation for this has been the resolution, or lack thereof, of seismic tomography in the mid-mantle region; however in this work I will explore the impact of compressibility on the dynamics of subducting slabs, specifically shear heating of the slab and latent heat of phase transformations. Most geodynamic models of subduction have used an incompressible formulation, thus because subducted slabs are assumed to be cold and stiff, the primary means of thermal equilibration is conduction. With an assumed sinking velocity of approximately 0.1 m/yr, a subducted slab reaches the core-mantle boundary in approximately 30 Myrs—too fast for significant conductive cooling of the downgoing slab. In this work I consider a whole-mantle geometry and include both phase transformations with associated latent heat and density changes from the olivine-wadsleyite-ringwoodite-bridgmanite system and the pyroxene-garnet system. The goal of this work is to understand both the eventual fate and thermal evolution of slabs beneath the transition zone.

  7. Gene Expression Profile in the Early Stage of Angiotensin II-induced Cardiac Remodeling: a Time Series Microarray Study in a Mouse Model

    Directory of Open Access Journals (Sweden)

    Meng-Qiu Dang

    2015-01-01

    Full Text Available Background/Aims: Angiotensin II (Ang II plays a critical role in the cardiac remodeling contributing to heart failure. However, the gene expression profiles induced by Ang II in the early stage of cardiac remodeling remain unknown. Methods: Wild-type male mice (C57BL/6 background, 10-weeek-old were infused with Ang II (1500 ng/kg/min for 7 days. Blood pressure was measured. Cardiac function and remodeling were examined by echocardiography, H&E and Masson staining. The time series microarrays were then conducted to detected gene expression profiles. Results: Microarray results identified that 1,489 genes were differentially expressed in the hearts at day 1, 3 and 7 of Ang II injection. These genes were further classified into 26 profiles by hierarchical cluster analysis. Of them, 4 profiles were significant (No. 19, 8, 21 and 22 and contained 904 genes. Gene Ontology showed that these genes mainly participate in metabolic process, oxidation-reduction process, extracellular matrix organization, apoptotic process, immune response, and others. Significant pathways included focal adhesion, ECM-receptor interaction, cytokine-cytokine receptor interaction, MAPK and insulin signaling pathways, which were known to play important roles in Ang II-induced cardiac remodeling. Moreover, gene co-expression networks analysis suggested that serine/cysteine peptidase inhibitor, member 1 (Serpine1, also known as PAI-1 localized in the core of the network. Conclusions: Our results indicate that many genes are mainly involved in metabolism, inflammation, cardiac fibrosis and hypertrophy. Serpine1 may play a central role in the development of Ang II-induced cardiac remodeling at the early stage.

  8. Influence of mantle viscosity structure and mineral grain size on fluid migration pathways in the mantle wedge.

    Science.gov (United States)

    Cerpa, N. G.; Wada, I.; Wilson, C. R.; Spiegelman, M. W.

    2016-12-01

    We develop a 2D numerical porous flow model that incorporates both grain size distribution and matrix compaction to explore the fluid migration (FM) pathways in the mantle wedge. Melt generation for arc volcanism is thought to be triggered by slab-derived fluids that migrate into the hot overlying mantle and reduce its melting temperature. While the narrow location of the arcs relative to the top of the slab ( 100±30 km) is a robust observation, the release of fluids is predicted to occur over a wide range of depth. Reconciling such observations and predictions remains a challenge for the geodynamic community. Fluid transport by porous flow depends on the permeability of the medium which in turn depends on fluid fraction and mineral grain size. The grain size distribution in the mantle wedge predicted by laboratory derived laws was found to be a possible mechanism to focusing of fluids beneath the arcs [Wada and Behn, 2015]. The viscous resistance of the matrix to the volumetric strain generates compaction pressure that affects fluid flow and can also focus fluids towards the arc [Wilson et al, 2014]. We thus have developed a 2D one-way coupled Darcy's-Stokes flow model (solid flow independent of fluid flow) for the mantle wedge that combines both effects. For the solid flow calculation, we use a kinematic-dynamic approach where the system is driven by the prescribed slab velocity. The solid rheology accounts for both dislocation and diffusion creep and we calculate the grain size distribution following Wada and Behn [2015]. In our fluid flow model, the permeability of the medium is grain size dependent and the matrix bulk viscosity depends on solid shear viscosity and fluid fraction. The fluid influx from the slab is imposed as a boundary condition at the base of the mantle wedge. We solve the discretized governing equations using the software package TerraFERMA. Applying a range of model parameter values, including slab age, slab dip, subduction rate, and fluid

  9. Self-Consistent Generation of Primordial Continental Crust in Global Mantle Convection Models

    Science.gov (United States)

    Jain, C.; Rozel, A.; Tackley, P. J.

    2017-12-01

    We present the generation of primordial continental crust (TTG rocks) using self-consistent and evolutionary thermochemical mantle convection models (Tackley, PEPI 2008). Numerical modelling commonly shows that mantle convection and continents have strong feedbacks on each other. However in most studies, continents are inserted a priori while basaltic (oceanic) crust is generated self-consistently in some models (Lourenco et al., EPSL 2016). Formation of primordial continental crust happened by fractional melting and crystallisation in episodes of relatively rapid growth from late Archean to late Proterozoic eras (3-1 Ga) (Hawkesworth & Kemp, Nature 2006) and it has also been linked to the onset of plate tectonics around 3 Ga. It takes several stages of differentiation to generate Tonalite-Trondhjemite-Granodiorite (TTG) rocks or proto-continents. First, the basaltic magma is extracted from the pyrolitic mantle which is both erupted at the surface and intruded at the base of the crust. Second, it goes through eclogitic transformation and then partially melts to form TTGs (Rudnick, Nature 1995; Herzberg & Rudnick, Lithos 2012). TTGs account for the majority of the Archean continental crust. Based on the melting conditions proposed by Moyen (Lithos 2011), the feasibility of generating TTG rocks in numerical simulations has already been demonstrated by Rozel et al. (Nature, 2017). Here, we have developed the code further by parameterising TTG formation. We vary the ratio of intrusive (plutonic) and extrusive (volcanic) magmatism (Crisp, Volcanol. Geotherm. 1984) to study the relative volumes of three petrological TTG compositions as reported from field data (Moyen, Lithos 2011). Furthermore, we systematically vary parameters such as friction coefficient, initial core temperature and composition-dependent viscosity to investigate the global tectonic regime of early Earth. Continental crust can also be destroyed by subduction or delamination. We will investigate

  10. Deep Mantle Origin for the DUPAL Anomaly?

    Science.gov (United States)

    Ingle, S.; Weis, D.

    2002-12-01

    Twenty years after the discovery of the Dupal Anomaly, its origin remains a geochemical and geophysical enigma. This anomaly is associated with the Southern Hemisphere oceanic mantle and is recognized by basalts with geochemical characteristics such as low 206Pb/204Pb and high 87Sr/86Sr. Both mid-ocean ridge basalts (MORB) and ocean island basalts (OIB) are affected, despite originating from melting at different depths and of different mantle sources. We compile geochemical data for both MORB and OIB from the three major oceans to help constrain the physical distribution and chemical composition of the Dupal Anomaly. There is a clear decrease in 206Pb/204Pb and an increase in 87Sr/86Sr with more southerly latitude for Indian MORB and OIB; these correlations are less obvious in the Atlantic and non-existent in the Pacific. The average* 143Nd/144Nd for Pacific and Atlantic OIB is 0.5129, but is lower for Indian OIB (0.5128). Interestingly, Pacific, Atlantic and Indian OIB all have 176Hf/177Hf averages of 0.2830. Indian MORB also record this phenomenon of low Nd with normal Hf isotopic compositions (Chauvel and Blichert-Toft, EPSL, 2001). Hf isotopes appear, therefore, to be a valid isotopic proxy for measuring the presence and magnitude of the Dupal Anomaly at specific locations. Wen (EPSL, 2001) reported a low-velocity layer at the D'' boundary beneath the Indian Ocean from which the Dupal Anomaly may originate. This hypothesis may be consistent with our compilations demonstrating that the long-lived Dupal Anomaly does not appear to be either mixing efficiently into the upper mantle or spreading to other ocean basins through time. We suggest that the Dupal source could be continually tapped by upwelling Indian Ocean mantle plumes. Plumes would then emplace pockets of Dupal material into the upper mantle and other ascending plumes might further disperse this material into the shallow asthenosphere. This could explain both the presence of the Dupal signature in MORB

  11. Blood transfusion and survival after surgery for Stage I and II breast cancer

    International Nuclear Information System (INIS)

    Herman, K.; Kolodziejski, L.

    1993-01-01

    The records of 690 Stage I and II breast cancer patients (31% of them with transfusions), who underwent mastectomy with axillary dissection were examined whether perioperative blood transfusion might be detrimental to survival. The overall 5- and 1-year survival rates for 477 patients who had not received transfusions were 75% and 63% respectively, compared with 66% and 49% for those who had transfusions (p=0.005). There was no significant difference between the group in any other of the most important prognostic factors. An analysis of the subpopulation of patients with favorable prognostic factors yielded similar results. A multivariate analysis indicated that blood transfusion was one of the four variables significantly related to survival. (author)

  12. An evaluation on time status of functional orthopedic treatment in class II skeletal patients with cervical vertebrae maturation stage (CVMS index

    Directory of Open Access Journals (Sweden)

    Dalili Z.

    2004-08-01

    Full Text Available Statement of Problem: Considerable response to functional orthopedic appliances treatment in class II skeletal patients occurs during pubertal growth spurt. Therefore, it seems necessary to investigate indices indicating mandibular growth pattern. It has been proved that analyzing cervical vertebral maturation stage is a more valid index than that of hand wrist. Purpose: The aim of this study was to evaluate the time status of functional orthopedic treatment in class II skeletal patients using CVMS index. Materials and Methods: In this descriptive-inferential study, lateral cephalometric radiographs of 153 class II skeletal patients with mandibular deficiency, before treatment, were studied by an oral and maxillofacial radiologist using the index of cervical vertebral maturation stage (CVMS and were categorized in three phases: CVMS I (desirable phase of treatment, CVMS II (ideal phase, and CVMS III (undesirable phase of treatment. Results: Statistical analysis ranked the prevalence of treatment phases as: 41.8% in desirable phase (CVMS I, 28.1% in ideal phase (CVMA II and 30% in undesirable phase (CVMS III. No significant differences were found between the three phases using Chi-square analysis. Time status of functional orthopedic treatment was also evaluated based on age and sex. The results showed significant differences between two sexes (P=0.032. Conclusion: The present study suggests the analysis of CVMS index, along with clinical criteria, in the determination of an ideal time for functional orthopedic treatment to prevent patients’ exhaustion during treatment Period.

  13. KRAS as a predictor of poor prognosis and benefit from postoperative FOLFOX chemotherapy in patients with stage II and III colorectal cancer.

    Science.gov (United States)

    Deng, Yanhong; Wang, Li; Tan, Shuyun; Kim, George P; Dou, Ruoxu; Chen, Dianke; Cai, Yue; Fu, Xinhui; Wang, Lei; Zhu, Jun; Wang, Jianping

    2015-08-01

    The KRAS gene frequently mutates in colorectal cancer (CRC). Here we investigated the prognostic and predictive role of KRAS mutation in patients with stage II or III CRC. A consecutive cohort of patients with stage II or III CRC from a single center database was studied. The association between KRAS status, adjuvant FOLFOX therapy, and 3-year disease-free survival (3-y DFS) was analyzed. Of our 433 patients, 166 (38.3%) exhibited the KRAS mutation. Among the 190 patients who did not receive adjuvant therapy, those with KRAS mutation tumors had a worse 3-y DFS (hazard ratio [HR], 1.924; 95% confidence interval [CI], 1.078-3.435; P = 0.027). Among patients who received adjuvant chemotherapy, KRAS mutation was not correlated with worse 3-y DFS (HR, 1.083; 95% CI, 0.618-1.899; P = 0.781). Adjuvant chemotherapy improved 3-y DFS only among patients with KRAS mutant tumors (78.0% vs 69.2%) on multivariate analysis adjusted for age, stage, grade, site, vessel invasion, and carcinoembryonic antigen level (HR, 0.454; 95% CI, 0.229-0.901; P = 0.024). In contrast, there was no benefit of adjuvant chemotherapy in the KRAS wild-type group (84.3% vs 82.0%). KRAS mutation indicates poor prognosis. FOLFOX adjuvant chemotherapy benefits patients with stage II or III colorectal cancer with KRAS mutant tumors and is worth further investigation. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  14. Mantle cell lymphoma relapsing at the lymphedematous arm.

    Directory of Open Access Journals (Sweden)

    Giuseppina Massini

    2013-02-01

    Full Text Available Lymphedema (LE is a chronic medical condition characterized by lymphatic fluid retention, resulting in tissue swelling. Cancer treatments involving lymph nodes can damage lymph drainage routes, causing accumulation of lymph fluid in the interstitial tissue of related limbs and body areas and secondary LE.  Basically, the LE has a negative impact on physical and mental quality of life. Moreover, 0.07-0.04% of long term survivors (most patients undergone mastectomy can develop the Stewart-Treves syndrome,  a rare and aggressive multifocal lymphangiosarcoma arising within the LE region. Here we describe a   45-year-old woman  with a massive LE of the left arm,  as a consequence of previous breast cancer,  who  was diagnosed after 4 years  of stage IV mantle cell lymphoma (MCL . The patient after obtaining complete remission with chemotherapy and ABMT  relapsed of MCL in lymphedema site.

  15. Sensitivity analysis of crustal correction and its error propagation to upper mantle residual gravity and density anomalies

    DEFF Research Database (Denmark)

    Herceg, Matija; Artemieva, Irina; Thybo, Hans

    2013-01-01

    ) uncertainties in the velocity-density conversion and (ii) uncertainties in knowledge of the crustal structure (thickness and average Vp velocities of individual crustal layers, including the sedimentary cover). In this study, we address both sources of possible uncertainties by applying different conversions...... from velocity to density and by introducing variations into the crustal structure which corresponds to the uncertainty of its resolution by high-quality and low-quality seismic models. We examine the propagation of these uncertainties into determinations of lithospheric mantle density. The residual...

  16. Validated Competing Event Model for the Stage I-II Endometrial Cancer Population

    Energy Technology Data Exchange (ETDEWEB)

    Carmona, Ruben; Gulaya, Sachin; Murphy, James D. [Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California (United States); Rose, Brent S. [Harvard Radiation Oncology Program, Harvard Medical School, Boston, Massachusetts (United States); Wu, John; Noticewala, Sonal [Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California (United States); McHale, Michael T. [Department of Reproductive Medicine, Division of Gynecologic Oncology, University of California San Diego, La Jolla, California (United States); Yashar, Catheryn M. [Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California (United States); Vaida, Florin [Department of Family and Preventive Medicine, Biostatistics and Bioinformatics, University of California San Diego Medical Center, San Diego, California (United States); Mell, Loren K., E-mail: lmell@ucsd.edu [Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California (United States)

    2014-07-15

    Purpose/Objectives(s): Early-stage endometrial cancer patients are at higher risk of noncancer mortality than of cancer mortality. Competing event models incorporating comorbidity could help identify women most likely to benefit from treatment intensification. Methods and Materials: 67,397 women with stage I-II endometrioid adenocarcinoma after total hysterectomy diagnosed from 1988 to 2009 were identified in Surveillance, Epidemiology, and End Results (SEER) and linked SEER-Medicare databases. Using demographic and clinical information, including comorbidity, we sought to develop and validate a risk score to predict the incidence of competing mortality. Results: In the validation cohort, increasing competing mortality risk score was associated with increased risk of noncancer mortality (subdistribution hazard ratio [SDHR], 1.92; 95% confidence interval [CI], 1.60-2.30) and decreased risk of endometrial cancer mortality (SDHR, 0.61; 95% CI, 0.55-0.78). Controlling for other variables, Charlson Comorbidity Index (CCI) = 1 (SDHR, 1.62; 95% CI, 1.45-1.82) and CCI >1 (SDHR, 3.31; 95% CI, 2.74-4.01) were associated with increased risk of noncancer mortality. The 10-year cumulative incidences of competing mortality within low-, medium-, and high-risk strata were 27.3% (95% CI, 25.2%-29.4%), 34.6% (95% CI, 32.5%-36.7%), and 50.3% (95% CI, 48.2%-52.6%), respectively. With increasing competing mortality risk score, we observed a significant decline in omega (ω), indicating a diminishing likelihood of benefit from treatment intensification. Conclusion: Comorbidity and other factors influence the risk of competing mortality among patients with early-stage endometrial cancer. Competing event models could improve our ability to identify patients likely to benefit from treatment intensification.

  17. Validated Competing Event Model for the Stage I-II Endometrial Cancer Population

    International Nuclear Information System (INIS)

    Carmona, Ruben; Gulaya, Sachin; Murphy, James D.; Rose, Brent S.; Wu, John; Noticewala, Sonal; McHale, Michael T.; Yashar, Catheryn M.; Vaida, Florin; Mell, Loren K.

    2014-01-01

    Purpose/Objectives(s): Early-stage endometrial cancer patients are at higher risk of noncancer mortality than of cancer mortality. Competing event models incorporating comorbidity could help identify women most likely to benefit from treatment intensification. Methods and Materials: 67,397 women with stage I-II endometrioid adenocarcinoma after total hysterectomy diagnosed from 1988 to 2009 were identified in Surveillance, Epidemiology, and End Results (SEER) and linked SEER-Medicare databases. Using demographic and clinical information, including comorbidity, we sought to develop and validate a risk score to predict the incidence of competing mortality. Results: In the validation cohort, increasing competing mortality risk score was associated with increased risk of noncancer mortality (subdistribution hazard ratio [SDHR], 1.92; 95% confidence interval [CI], 1.60-2.30) and decreased risk of endometrial cancer mortality (SDHR, 0.61; 95% CI, 0.55-0.78). Controlling for other variables, Charlson Comorbidity Index (CCI) = 1 (SDHR, 1.62; 95% CI, 1.45-1.82) and CCI >1 (SDHR, 3.31; 95% CI, 2.74-4.01) were associated with increased risk of noncancer mortality. The 10-year cumulative incidences of competing mortality within low-, medium-, and high-risk strata were 27.3% (95% CI, 25.2%-29.4%), 34.6% (95% CI, 32.5%-36.7%), and 50.3% (95% CI, 48.2%-52.6%), respectively. With increasing competing mortality risk score, we observed a significant decline in omega (ω), indicating a diminishing likelihood of benefit from treatment intensification. Conclusion: Comorbidity and other factors influence the risk of competing mortality among patients with early-stage endometrial cancer. Competing event models could improve our ability to identify patients likely to benefit from treatment intensification

  18. Mantle convection patterns reveal the enigma of the Red Sea rifting

    Science.gov (United States)

    Petrunin, Alexey; Kaban, Mikhail; El Khrepy, Sami; Al-Arifi, Nassir

    2017-04-01

    Initiation and further development of the Red Sea rift (RSR) is usually associated with the Afar plume at the Oligocene-Miocene separating the Arabian plate from the rest of the continent. Usually, the RSR is divided into three parts with different geological, tectonic and geophysical characteristics, but the nature of this partitioning is still debatable. To understand origin and driving forces responsible for the tectonic partitioning of the RSR, we have developed a global mantle convection model based on the refined density model and viscosity distribution derived from tectonic, rheological and seismic data. The global density model of the upper mantle is refined for the Middle East based on the high-resolution 3D model (Kaban et al., 2016). This model based on a joint inversion of the residual gravity and residual topography provides much better constraints on the 3D density structure compared to the global model based on seismic tomography. The refined density model and the viscosity distribution based on a homologous temperature approach provide an initial setup for further numerical calculations. The present-day snapshot of the mantle convection is calculated by using the code ProSpher 3D that allows for strong lateral variations of viscosity (Petrunin et al., 2013). The setup includes weak plate boundaries, while the measured GPS velocities are used to constrain the solution. The resulting mantle flow patterns show clear distinctions among the mantle flow patterns below the three parts of the RSR. According to the modeling results, tectonics of the southern part of the Red Sea is mainly determined by the Afar plume and the Ethiopian rift opening. It is characterized by a divergent mantle flow, which is connected to the East African Rift activity. The rising mantle flow is traced down to the transition zone and continues in the lower mantle for a few thousand kilometers south-west of Afar. The hot mantle anomaly below the central part of the RSR can be

  19. Geophysical constraints on the mantle structure of the Canadian Cordillera and North America Craton

    Science.gov (United States)

    Yu, T. C.; Currie, C. A.; Unsworth, M. J.

    2017-12-01

    In western Canada, geophysical data indicate that there is a pronounced contrast in mantle structure between the Canadian Cordillera (CC) and North America craton (NAC). The CC is characterized by lower mantle seismic velocity, higher surface heat flow, lower mantle electrical resistivity and lower effective elastic thickness. These observations are consistent with two distinct thermal regimes: the CC has hot and thin lithosphere, while the NAC lithosphere is cool and thick. The boundary between the CC and NAC coincides with the south-north trending Rocky Mountain Trench - Tintina Fault system. Earlier studies have hypothesized that the thin CC lithosphere is maintained by small-scale convection of hydrated mantle, whereas the NAC lithosphere is dry and resistant to thinning. Here, we test this hypothesis through a detailed examination of two independent data sets: (1) seismic shear-wave (Vs) tomography models and (2) magnetotelluric (MT) measurements of mantle electrical resistivity. We analyze tomography model NA07 at 50-250 km depth and create a mapping of Vs to temperature based on mantle composition (via Perple_X) and a correction for anelasticity. For the CC, the calculated temperature is relatively insensitive to mantle composition but strongly depends on the water content and anelastic correction. With a laboratory-based correction, the estimated temperature is 1150 °C at 100 km depth for wet mantle, compared to 1310 °C for dry mantle; no melt is predicted in either case. An empirical anelastic correction predicts a 115 °C hotter mantle and likely some melt. In contrast, composition is the main control on the calculated temperature for the NAC, especially at depths electrical resistivity is sensitive to mantle temperature and hydration.

  20. Expression of PAT and NPT II proteins during the developmental stages of a genetically modified pepper developed in Korea.

    Science.gov (United States)

    Kim, Hyo Jin; Lee, Si Myung; Kim, Jae Kwang; Ryu, Tae Hun; Suh, Seok Cheol; Cho, Hyun Suk

    2010-10-27

    Estimation of the protein levels introduced in a biotechnology-derived product is conducted as part of an overall safety assessment. An enzyme-linked immunosorbent assay (ELISA) was used to analyze phosphinothricin acetyltransferase (PAT) and neomycin phosphotransferase II (NPT II) protein expression in a genetically modified (GM) pepper plant developed in Korea. PAT and NPT II expression levels, based on both dry weight and fresh weight, were variable among different plant generations and plant sections from isolated genetically modified organism (GMO) fields at four developmental stages. PAT expression was highest in leaves at anthesis (11.44 μg/gdw and 2.17 μg/gfw) and lowest in roots (0.12 μg/gdw and 0.01 μg/gfw). NPT II expression was also highest in leaves at anthesis (17.31 μg/gdw and 3.41 μg/gfw) and lowest in red pepper (0.65 μg/gdw and 0.12 μg/gfw). In pollen, PAT expression was 0.59-0.62 μg/gdw, while NPT II was not detected. Both PAT and NPT II showed a general pattern of decreased expression with progression of the growing season. As expected, PAT and NPT II protein expression was not detectable in control pepper plants.

  1. Deep mantle forces and the uplift of the Colorado Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Moucha, R; Forte, A M; Rowley, D B; Mitrovica, J X; Simmons, N A; Grand, S P

    2009-06-23

    Since the advent of plate tectonics, it has been speculated that the northern extension of the East Pacific Rise, specifically its mantle source, has been over-ridden by the North American Plate in the last 30 Myrs. Consequently, it has also been postulated that the opening of the Gulf of California, the extension in the Basin and Range province, and the uplift of the Colorado Plateau are the resulting continental expressions of the over-ridden mantle source of the East Pacific Rise. However, only qualitative models based solely on surface observations and heuristic, simplified conceptions of mantle convection have been used in support or against this hypothesis. We introduce a quantitative model of mantle convection that reconstructs the detailed motion of a warm mantle upwelling over the last 30 Myrs and its relative advance towards the interior of the southwestern USA. The onset and evolution of the crustal uplift in the central Basin and Range province and the Colorado Plateau is determined by tracking the topographic swell due to this mantle upwelling through time. We show that (1) the extension and magmatism in the central Basin and Range province between 25 and 10 Ma coincides with the reconstructed past position of this focused upwelling, and (2) the southwestern portion of the Colorado Plateau experienced significant uplift between 10 Ma and 5 Ma that progressed towards the northeastern portion of the plateau. These uplift estimates are consistent with a young, ca. 6 Ma, Grand Canyon model and the recent commencement of mafic magmatism.

  2. Lithologic Control on the Form of Soil Mantled Hillslopes

    Science.gov (United States)

    Johnstone, S. A.; Hilley, G. E.

    2014-12-01

    Slopes on steady-state soil-mantled hillslopes tend to increase downslope in a way that balances local transport capacity with the sediment supplied from progressively larger source areas. Most predictions for the transport of soil depend purely on topographic slope and constants. Thus, soil mantled topography should evolve toward smooth forms in which soils act to buffer these forms from the underlying geologic structure. However, in the Gabilan Mesa, CA, oscillations in the slope of soil-mantled hillslopes mirror oscillations in the underlying stratigraphy. Using field measurements of stratigraphy and soil depths, topographic analysis, and numerical modeling, we demonstrate that variations in rock type can impact the form of soil-mantled hillslopes. Specifically, variations in the properties of underlying rocks may yield different soil thicknesses. Balancing transport rates across these variations in thickness requires slopes to change when soil transport depends on both soil thickness and slope. A compilation of published data on the variation in activity with depth of various transport processes provides the basis for a geomorphic transport law (GTL) that generalizes the depth dependence of various transport processes. While this GTL is explicitly depth dependent, it is also capable of describing situations in which hillslope transport is relatively insensitive to variations in thickness and therefore essentially equivalent to existing formulations. We use dimensional analysis and numerical modeling to demonstrate the conditions under which transport on soil mantled slopes, and consequently topographic forms, may be sensitive to variations in soil thickness and therefore lithology.

  3. Tumors with unmethylated MLH1 and the CpG island methylator phenotype are associated with a poor prognosis in stage II colorectal cancer patients.

    Science.gov (United States)

    Fu, Tao; Liu, Yanliang; Li, Kai; Wan, Weiwei; Pappou, Emmanouil P; Iacobuzio-Donahue, Christine A; Kerner, Zachary; Baylin, Stephen B; Wolfgang, Christopher L; Ahuja, Nita

    2016-12-27

    We previously developed a novel tumor subtype classification model for duodenal adenocarcinomas based on a combination of the CpG island methylator phenotype (CIMP) and MLH1 methylation status. Here, we tested the prognostic value of this model in stage II colorectal cancer (CRC) patients. Tumors were assigned to CIMP+/MLH1-unmethylated (MLH1-U), CIMP+/MLH1-methylated (MLH1-M), CIMP-/MLH1-U, or CIMP-/MLH1-M groups. Age, tumor location, lymphovascular invasion, and mucin production differed among the four patient subgroups, and CIMP+/MLH1-U tumors were more likely to have lymphovascular invasion and mucin production. Kaplan-Meier analyses revealed differences in both disease-free survival (DFS) and overall survival (OS) among the four groups. In a multivariate analysis, CIMP/MLH1 methylation status was predictive of both DFS and OS, and DFS and OS were shortest in CIMP+/MLH1-U stage II CRC patients. These results suggest that tumor subtype classification based on the combination of CIMP and MLH1 methylation status is informative in stage II CRC patients, and that CIMP+/MLH1-U tumors exhibit aggressive features and are associated with poor clinical outcomes.

  4. Complex Anisotropic Structure of the Mantle Wedge Beneath Kamchatka Volcanoes

    Science.gov (United States)

    Levin, V.; Park, J.; Gordeev, E.; Droznin, D.

    2002-12-01

    A wedge of mantle material above the subducting lithospheric plate at a convergent margin is among the most dynamic environments of the Earth's interior. Deformation and transport of solid and volatile phases within this region control the fundamental process of elemental exchange between the surficial layers and the interior of the planet. A helpful property in the study of material deformation and transport within the upper mantle is seismic anisotropy, which may reflect both microscopic effects of preferentialy aligned crystals of olivine and orthopyroxene and macroscopic effects of systematic cracks, melt lenses, layering etc. Through the mapping of anisotropic properties within the mantle wedge we can establish patterns of deformation. Volatile content affects olivine alignment, so regions of anomalous volatile content may be evident. Indicators of seismic anisotropy commonly employed in upper mantle studies include shear wave birefringence and mode-conversion between compressional and shear body waves. When combined together, these techniques offer complementary constraints on the location and intensity of anisotropic properties. The eastern coast of southern Kamchatka overlies a vigorous convergent margin where the Pacific plate descends at a rate of almost 80 mm/yr towards the northwest. We extracted seismic anisotropy indicators from two data sets sensitive to the anisotropic properties of the uppermost mantle. Firstly, we evaluated teleseismic receiver functions for a number of sites, and found ample evidence for anisotropicaly-influenced P-to-S mode conversion. Secondly, we measured splitting in S waves of earthquakes with sources within the downgoing slab. The first set of observations provides constraints on the depth ranges where strong changes in anisotropic properties take place. The local splitting data provides constraints on the cumulative strength of anisotropic properties along specific pathways through the mantle wedge and possibly parts of

  5. A scoring system based on artificial neural network for predicting 10-year survival in stage II A colon cancer patients after radical surgery

    Science.gov (United States)

    Jiang, Wu; Lu, Shi-Xun; Lu, Zhen-Hai; Li, Pei-Xing; Yun, Jing-Ping; Zhang, Rong-Xin; Pan, Zhi-Zhong; Wan, De-Sen

    2016-01-01

    Nearly 20% patients with stage II A colon cancer will develop recurrent disease post-operatively. The present study aims to develop a scoring system based on Artificial Neural Network (ANN) model for predicting 10-year survival outcome. The clinical and molecular data of 117 stage II A colon cancer patients from Sun Yat-sen University Cancer Center were used for training set and test set; poor pathological grading (score 49), reduced expression of TGFBR2 (score 33), over-expression of TGF-β (score 45), MAPK (score 32), pin1 (score 100), β-catenin in tumor tissue (score 50) and reduced expression of TGF-β in normal mucosa (score 22) were selected as the prognostic risk predictors. According to the developed scoring system, the patients were divided into 3 subgroups, which were supposed with higher, moderate and lower risk levels. As a result, for the 3 subgroups, the 10-year overall survival (OS) rates were 16.7%, 62.9% and 100% (P < 0.001); and the 10-year disease free survival (DFS) rates were 16.7%, 61.8% and 98.8% (P < 0.001) respectively. It showed that this scoring system for stage II A colon cancer could help to predict long-term survival and screen out high-risk individuals for more vigorous treatment. PMID:27008710

  6. A scoring system based on artificial neural network for predicting 10-year survival in stage II A colon cancer patients after radical surgery.

    Science.gov (United States)

    Peng, Jian-Hong; Fang, Yu-Jing; Li, Cai-Xia; Ou, Qing-Jian; Jiang, Wu; Lu, Shi-Xun; Lu, Zhen-Hai; Li, Pei-Xing; Yun, Jing-Ping; Zhang, Rong-Xin; Pan, Zhi-Zhong; Wan, De Sen

    2016-04-19

    Nearly 20% patients with stage II A colon cancer will develop recurrent disease post-operatively. The present study aims to develop a scoring system based on Artificial Neural Network (ANN) model for predicting 10-year survival outcome. The clinical and molecular data of 117 stage II A colon cancer patients from Sun Yat-sen University Cancer Center were used for training set and test set; poor pathological grading (score 49), reduced expression of TGFBR2 (score 33), over-expression of TGF-β (score 45), MAPK (score 32), pin1 (score 100), β-catenin in tumor tissue (score 50) and reduced expression of TGF-β in normal mucosa (score 22) were selected as the prognostic risk predictors. According to the developed scoring system, the patients were divided into 3 subgroups, which were supposed with higher, moderate and lower risk levels. As a result, for the 3 subgroups, the 10-year overall survival (OS) rates were 16.7%, 62.9% and 100% (P < 0.001); and the 10-year disease free survival (DFS) rates were 16.7%, 61.8% and 98.8% (P < 0.001) respectively. It showed that this scoring system for stage II A colon cancer could help to predict long-term survival and screen out high-risk individuals for more vigorous treatment.

  7. Management of stage I and II A/B avascular necrosis of femoral head with core decompression autologous cancellous bone grafting and platelet rich plasma factors

    Directory of Open Access Journals (Sweden)

    Tushar Agarwal

    2015-01-01

    Full Text Available Background: Avascular necrosis (AVN of the femoral head is a progressive disease that generally affects patients in the third through fifth decades of life; if left untreated, it leads to complete deterioration of the hip joint. Treatments range from simple decompression of the femoral head, to bone grafting of the involved area, or by using a vascularized fibular graft with varying degree of success. In most instances, the disease progresses further causing secondary arthritis. We present a study of management of early stage AVN (stage I and II A/B of Ficat Arlet classification with core decompression autologous cancellous bone grafting along with platelet rich plasma. Aims: To evaluate the results of the above modality in the management of AVN of the hip. Settings and Design: This prospective study of 30 cases was done during the period of 2011-2013. Materials and Methods: Patients with stage I and II A/B were treated with the above modality and were followed up for 1-year. The results were evaluated on the basis of progression or remission of the disease by radiographic studies, preoperative and postoperative Harris hip score (HHS, age and sex distribution. Statistical Analysis Used: Primer software for calculating the statistical data was used and paired t-test was applied to all the data. Results: Show males were more affected than females and average age group of presentation in stage I and II was 29 years (22-55. The most common cause was idiopathic followed by steroid use. Average preoperative HHS was 56.80 and postoperative HHS was 79.73. 60% (18 showed remission of the disease (radiographically compared to preoperative stage at 1-year follow-up, in 30% (9 disease did not progress further and 10% (3 progressed and required arthroplasty. Conclusion: Management of stage I and II A/B AVN of femur showed good satisfactory results in terms of disease remission and prevention of the further progress of the disease by the above method at 1

  8. The Importance of Lower Mantle Structure to Plate Stresses and Plate Motions

    Science.gov (United States)

    Holt, W. E.; Wang, X.; Ghosh, A.

    2016-12-01

    Plate motions and plate stresses are widely assumed as the surface expression of mantle convection. The generation of plate tectonics from mantle convection has been studied for many years. Lithospheric thickening (or ridge push) and slab pull forces are commonly accepted as the major driving forces for the plate motions. However, the importance of the lower mantle to plate stresses and plate motions remains less clear. Here, we use the joint modeling of lithosphere and mantle dynamics approach of Wang et al. (2015) to compute the tractions originating from deeper mantle convection and follow the method of Ghosh et al. (2013) to calculate gravitational potential energy per unit area (GPE) based on Crust 1.0 (Laske et al., 2013). Absolute values of deviatoric stresses are determined by the body force distributions (GPE gradients and traction magnitudes applied at the base of the lithosphere). We use the same relative viscosity model that Ghosh et al. (2013) used, and we solve for one single adjustable scaling factor that multiplies the entire relative viscosity field to provide absolute values of viscosity throughout the lithosphere. This distribution of absolute values of lithosphere viscosities defines the magnitudes of surface motions. In this procedure, the dynamic model first satisfies the internal constraint of no-net-rotation of motions. The model viscosity field is then scaled by the single factor until we achieve a root mean square (RMS) minimum between computed surface motions and the kinematic no-net-rotation (NNR) model of Kreemer et al. (2006). We compute plate stresses and plate motions from recently published global tomography models (over 70 based on Wang et al., 2015). We find that RMS misfits are significantly reduced when details of lower mantle structure from the latest tomography models are added to models that contain only upper and mid-mantle density distributions. One of the key reasons is that active upwelling from the Large Low Shear

  9. Density structure of the cratonic mantle in southern Africa

    DEFF Research Database (Denmark)

    Artemieva, Irina; Vinnik, Lev P.

    2016-01-01

    contributions of the both factors to surface topography in the cratons of southern Africa. Our analysis takes advantage of the SASE seismic experiment which provided high resolution regional models of the crustal thickness.We calculate the model of density structure of the lithospheric mantle in southern Africa...... that mantle residual (dynamic) topography may be associated with the low-density region below the depth of isostatic compensation. A possible candidate is the low velocity layer between the lithospheric base and the mantle transition zone, where a temperature anomaly of 100-200. °C in a ca. 100-150. km thick...... layer may explain the observed reduction in Vs velocity and may produce ca. 0.5-1.0. km to the regional topographic uplift....

  10. Geophysical Investigation of Upper Mantle Anomalies of the Australian-Antarctic Ridge

    Science.gov (United States)

    Park, S. H.; Choi, H.; Kim, S. S.; Lin, J.

    2017-12-01

    Australian-Antarctic Ridge (AAR) is situated between the Pacific-Antarctic Ridge (PAR) and Southeast Indian Ridge (SEIR), extending eastward from the Australian-Antarctic Discordance (AAD). Much of the AAR has been remained uncharted until 2011 because of its remoteness and harsh weather conditions. Since 2011, four multidisciplinary expeditions initiated by the Korea Polar Research Institute (KOPRI) have surveyed the little-explored eastern ends of the AAR and investigated the tectonics, geochemistry, and hydrothermal activity of this intermediate spreading system. Recent isotope studies using the new basalt samples from the AAR have led to the new hypothesis of the Southern Ocean mantle domain (SOM), which may have originated from the super-plume activity associated with the Gondwana break-up. In this study, we characterize the geophysics of the Southern Ocean mantle using the newly acquired shipboard bathymetry and available geophysical datasets. First, we computed residual mantle Bouguer gravity anomalies (RMBA), gravity-derived crustal thickness, and residual topography along the AAR in order to obtain a geological proxy for regional variations in magma supply. The results of these analyses revealed that the southern flank of the AAR is associated with shallower seafloor, more negative RMBA, thicker crust, and/or less dense mantle in comparison to the conjugate northern flank. Furthermore, this north-south asymmetry becomes more prominent toward the central ridge segments of the AAR. Interestingly, the along-axis depths of the entire AAR are significantly shallower than the neighboring ridge systems and the global ridges of intermediate spreading rates. Such shallow depths are also correlated with regional negative geoid anomalies. Furthermore, recent mantle tomography models consistently showed that the upper mantle (< 250 km) below the AAR has low S-wave velocities, suggesting that it may be hotter than the nearby ridges. Such regional-scale anomalies of the

  11. Slab Penetration vs. Slab Stagnation: Mantle Reflectors as an Indicator

    Science.gov (United States)

    Okeler, A.; Gu, Y. J.; Schultz, R.; Contenti, S. M.

    2011-12-01

    Subducting oceanic lithosphere along convergent margins may stagnate near the base of the upper mantle or penetrate into the lower mantle. These dynamic processes cause extensive thermal and compositional variations, which can be observed in terms of impedance contrast (reflectivity) and topography of mantle transition zone (MTZ) discontinuities, i.e., 410- and 660-km discontinuities. In this study, we utilize ~ 15000 surface-reflected shear waves (SS) and their precursory arrivals (S410S and S660S) to analyze subduction related deformations on mantle reflectivity structure. We apply pre-stack, time-to-depth migration technique to SS precursors, and move weak underside reflections using PREM-predicted travel-time curves. Common Mid-point gathers are formed to investigate structure under the western Pacific, south America, and Mediterranean convergent boundaries. In general, mantle reflectivity structures are consistent with previous seismic tomography models. In regions of slab penetration (e.g., southern Kurile arc, Aegean Sea), our results show 1) a substantial decrease in S660S amplitude, and 2) strong lower mantle reflector(s) at ~ 900 km depth. These reflective structures are supported by zones of high P and S velocities extending into the lower mantle. Our 1-D synthetic simulations suggest that the decreasing S660S amplitudes are, at least partially, associated with shear wave defocusing due to changes in reflector depth (by ±20 km) within averaging bin. Assuming a ~500 km wide averaging area, a dipping reflector with 6-8 % slope can reduce the amplitude of a SS precursor by ~50%. On the other hand, broad depressions with strong impedance contrast at the base of the MTZ characterize the regions of slab stagnation, such as beneath the Tyrrhenian Sea and northeastern China. For the latter region, substantial topography on the 660-km discontinuity west of the Wadati-Benioff zone suggests that the stagnant part of the Pacific plate across Honshu arc is not

  12. Mantle transition zone structure beneath the Canadian Shield

    Science.gov (United States)

    Thompson, D. A.; Helffrich, G. R.; Bastow, I. D.; Kendall, J. M.; Wookey, J.; Eaton, D. W.; Snyder, D. B.

    2010-12-01

    The Canadian Shield is underlain by one of the deepest and most laterally extensive continental roots on the planet. Seismological constraints on the mantle structure beneath the region are presently lacking due to the paucity of stations in this remote area. Presented here is a receiver function study on transition zone structure using data from recently deployed seismic networks from the Hudson Bay region. High resolution images based on high signal-to-noise ratio data show clear arrivals from the 410 km and 660 km discontinuities, revealing remarkably little variation in transition zone structure. Transition zone thickness is close to the global average (averaging 245 km across the study area), and any deviations in Pds arrival time from reference Earth models can be readily explained by upper-mantle velocity structure. The 520 km discontinuity is not a ubiquitous feature, and is only weakly observed in localised areas. These results imply that the Laurentian root is likely confined to the upper-mantle and if any mantle downwelling exists, possibly explaining the existence of Hudson Bay, it is also confined to the upper 400 km. Any thermal perturbations at transition zone depths associated with the existence of the root, whether they be cold downwellings or elevated temperatures due to the insulating effect of the root, are thus either non-existent or below the resolution of the study.

  13. Preliminary investigation of stereotactic body radiation therapy for medically inoperable stage I/II non-small cell lung cancer

    International Nuclear Information System (INIS)

    Guo Jindong; Lu Changxing; Wang Jiaming; Liu Jun; Li Hongxuan; Wang Changlu; Gao Lanting; Zhao Lei

    2011-01-01

    Objective: To evaluate the therapeutic efficacy and treatment-related toxicity of stereotactic body radiation therapy (SBRT) in patients with medically inoperable stage I/II non-small cell lung cancer (NSCLC). Methods: SBRT was applied to 30 patients, including clinically staged T 1 , T 2 (≤5 cm) or T 3 (chest wall primary tumors only), N 0 , M 0 ,biopsy-confirmed NSCLC. All patients were precluded from lobotomy because of physical condition or comorbidity. No patients developed tumors of any T-stage in the proximal zone. SBRT was performed with the total dose of 50 Gy to 70 Gy in 10 - 11 fractions during 12 - 15 days. prescription line was set onthe edge of the PTV. Results: The follow-up rate was 100%. The number of patients who completed the 1-, and 2-year follow-up were 15, and 10, respectively. All 30 patients completed therapy as planned. The complete response (CR), partial response (PR) and stable disease (SD) rates were 37%, 53% and 3%, respectively. With a median follow-up of 16 months (range, 4-36 months), Kaplan-Meier local control at 2 years was 94%. The 2-year overall survival was 84% and the 2-year cancer specific survival was 90%. Seven patients(23%) developed Grade 2 pneumonitis, no grade > 2 acute or late lung toxicity was observed. No one developed chest wall pain. Conclusions: It is feasible to deliver 50 Gy to 70 Gy of SBRT in 10 - 11 fractions for medically inoperable patients with stage I / II NSCLC. It was associated with low incidence of toxicities and provided sustained local tumor control.The preliminary investigation indicated the cancer specific survival probability of SBRT was high. It is necessary to perform similar investigation in a larger number of patients with long-term follow-up. (authors)

  14. High porosity harzburgite and dunite channels for the transport of compositionally heterogeneous melts in the mantle: II. Geochemical consequences

    Science.gov (United States)

    Liang, Y.; Schiemenz, A.; Xia, Y.; Parmentier, E.

    2009-12-01

    In a companion numerical study [1], we explored the spatial distribution of high porosity harzburgite and dunite channels produced by reactive dissolution of orthopyroxene (opx) in an upwelling mantle column and identified a number of new features. In this study, we examine the geochemical consequences of channelized melt flow under the settings outlined in [1] with special attention to the transport of compositionally heterogeneous melts and their interactions with the surrounding peridotite matrix during melt migration in the mantle. Time-dependent transport equations for a trace element in the interstitial melt and solids that include advection, dispersion, and melt-rock reaction were solved in a 2-D upwelling column using the high-order numerical methods outlined in [1]. The melt and solid velocities were taken from the steady state or quasi-steady state solutions of [1]. In terms of trace element fractionation, the simulation domain can be divided into 4 distinct regions: (a) high porosity harzburgite channel, overlain by; (b) high porosity dunite channel; (c) low porosity compacting boundary layer surrounding the melt channels; and (d) inter-channel regions outside (c). In the limit of local chemical equilibrium, melting in region (d) is equivalent to batch melting, whereas melting and melt extraction in (c) is more close to fractional melting with the melt suction rate first increase from the bottom of the melting column to a maximum near the bottom of the dunite channel and then decrease upward in the compacting boundary layer. The melt composition in the high porosity harzburgite channel is similar to that produced by high-degree batch melting (up to opx exhaustion), whereas the melt composition in the dunite is a weighted average of the ultra-depleted melt from the harzburgite channel below, the expelled melt from the compacting boundary layer, and melt produced by opx dissolution along the sidewalls of the dunite channel. Compaction within the dunite

  15. Water-induced convection in the Earth's mantle transition zone

    Science.gov (United States)

    Richard, Guillaume C.; Bercovici, David

    2009-01-01

    Water enters the Earth's mantle by subduction of oceanic lithosphere. Most of this water immediately returns to the atmosphere through arc volcanism, but a part of it is expected as deep as the mantle transition zone (410-660 km depth). There, slabs can be deflected and linger before sinking into the lower mantle. Because it lowers the density and viscosity of the transition zone minerals (i.e., wadsleyite and ringwoodite), water is likely to affect the dynamics of the transition zone mantle overlying stagnant slabs. The consequences of water exchange between a floating slab and the transition zone are investigated. In particular, we focus on the possible onset of small-scale convection despite the adverse thermal gradient (i.e., mantle is cooled from below by the slab). The competition between thermal and hydrous effects on the density and thus on the convective stability of the top layer of the slab is examined numerically, including water-dependent density and viscosity and temperature-dependent water solubility. For plausible initial water content in a slab (≥0.5 wt %), an episode of convection is likely to occur after a relatively short time delay (5-20 Ma) after the slab enters the transition zone. However, water induced rheological weakening is seen to be a controlling parameter for the onset time of convection. Moreover, small-scale convection above a stagnant slab greatly enhances the rate of slab dehydration. Small-scale convection also facilitates heating of the slab, which in itself may prolong the residence time of the slab in the transition zone.

  16. Multiple-frequency tomography of the upper mantle beneath the African/Iberian collision zone

    Science.gov (United States)

    Bonnin, Mickaël; Nolet, Guust; Villaseñor, Antonio; Gallart, Josep; Thomas, Christine

    2014-09-01

    During the Cenozoic, the geodynamics of the western Mediterranean domain has been characterized by a complex history of subduction of Mesozoic oceanic lithosphere. The final stage of these processes is proposed to have led to the development of the Calabria and Gibraltar arcs, whose formation is still under debate. In this study, we take advantage of the dense broad-band station networks now available in the Alborán Sea region, to develop a high-resolution 3-D tomographic P velocity model of the upper mantle beneath the African/Iberian collision zone that will better constraint the past dynamics of this zone. The model is based on 13200 teleseismic arrival times recorded between 2008 and 2012 at 279 stations for which cross-correlation delays are measured with a new technique in different frequency bands centred between 0.03 and 1.0 Hz, and for the first time interpreted using multiple frequency tomography. Our model shows, beneath the Alborán Sea, a strong (4 per cent) fast vertically dipping anomaly observed to at least 650 km depth. The arched shape of this anomaly, and its extent at depth, are coherent with a lithospheric slab, thus favouring the hypothesis of a westward consumption of the Ligurian ocean slab by roll-back during Cenozoic. In addition to this fast anomaly in the deep upper mantle, high intensity slow anomalies are widespread in the lithosphere and asthenosphere beneath Morocco and southern Spain. These anomalies are correlated at the surface with the position of the Rif and Atlas orogens and with Cenozoic volcanic fields. We thus confirm the presence, beneath Morocco, of an anomalous (hot?) upper mantle, but without clear indication for a lateral spreading of the Canary plume to the east.

  17. Mantle roots of the Emeishan plume: an evaluation based on teleseismic P-wave tomography

    Directory of Open Access Journals (Sweden)

    C. He

    2017-11-01

    Full Text Available The voluminous magmatism associated with large igneous provinces (LIPs is commonly correlated to upwelling plumes from the core–mantle boundary (CMB. Here we analyse seismic tomographic data from the Emeishan LIP in southwestern China. Our results reveal vestiges of delaminated crustal and/or lithospheric mantle, with an upwelling in the upper mantle beneath the Emeishan LIP rather than a plume rooted in the CMB. We suggest that the magmatism and the Emeishan LIP formation might be connected with the melting of delaminated lower crustal and/or lithospheric components which resulted in plume-like upwelling from the upper mantle or from the mantle transition zone.

  18. Oceanic mantle rocks reveal evidence for an ancient, 1.2-1.3 Ga global melting event

    Science.gov (United States)

    Dijkstra, A. H.; Sergeev, D.; McTaminey, L.; Dale, C. W.; Meisel, T. C.

    2011-12-01

    It is now increasingly being recognized that many oceanic peridotites are refertilized harzburgites, and that the refertilization often masks an extremely refractory character of the original mantle rock 'protolith'. Oceanic peridotites are, when the effects of melt refertilization are undone, often too refractory to be simple mantle melting residues after the extraction of mid-ocean ridge basalts at a spreading center. Rhenium-osmium isotope analysis is a powerful method to look through the effects of refertilization and to obtain constraints on the age of the melting that produced the refractory mantle protolith. Rhenium-depletion model ages of such anomalously refractory oceanic mantle rocks - found as abyssal peridotites or as mantle xenoliths on ocean islands - are typically >1 Ga, i.e., much older than the ridge system at which they were emplaced. In my contribution I will show results from two case studies of refertilized anciently depleted mantle rocks (Macquarie Island 'abyssal' peridotites and Lanzarote mantle xenoliths). Interestingly, very refractory oceanic mantle rocks from sites all around the world show recurring evidence for a Mesoproterozoic (~1.2-1.3 Ga) melting event [1]. Therefore, oceanic mantle rocks seem to preserve evidence for ancient melting events of global significance. Alternatively, such mantle rocks may be samples of rafts of ancient continental lithospheric mantle. Laser-ablation osmium isotope 'dating' of large populations of individual osmium-bearing alloys from mantle rocks is the key to better constrain the nature and significance of these ancient depletion events. Osmium-bearing alloys form when mantle rocks are melted to high-degrees. We have now extracted over >250 detrital osmium alloys from placer gold occurrences in the river Rhine. These alloys are derived from outcrops of ophiolitic mantle rocks in the Alps, which include blocks of mantle rocks emplaced within the Tethys Ocean, and ultramafic lenses of unknown

  19. A Model of Continental Growth and Mantle Degassing Comparing Biotic and Abiotic Worlds

    Science.gov (United States)

    Höning, D.; Hansen-Goos, H.; Spohn, T.

    2012-12-01

    While examples for interaction of the biosphere with the atmosphere can be easily cited (e.g., production and consumption of O2), interaction between the biosphere and the solid planet and its interior is much less established. It has been argued (e.g., Rosing et al. 2006; Sleep et al, 2012) that the formation of continents could be a consequence of bioactivity harvesting solar energy through photosynthesis to help build the continents and that the mantle should carry a chemical biosignature. We present an interaction model that includes mantle convection, mantle water vapor degassing at mid-oceanic ridges and regassing through subduction zones, continental crust formation and erosion and water storage and transport in a porous oceanic crust that includes hydrous mineral phases. The mantle viscosity in this model depends on the water concentration in the mantle. We use boundary layer theory of mantle convection to parameterize the mantle convection flow rate and assume that the plate speed equals the mantle flow rate. The biosphere enters the calculation through the assumption that the continental erosion rate is enhanced by a factor of several through bioactivity and through an assumed reduction of the kinetic barrier to diagenetic and metamorphic reactions (e.g., Kim et al. 2004) in the sedimentary basins in subduction zones that would lead to increased water storage capacities. We further include a stochastic model of continent-to-continent interactions that limits the effective total length of subduction zones. We use present day parameters of the Earth and explore a phase plane spanned by the percentage of surface coverage of the Earth by continents and the total water content of the mantle. We vary the ratio of the erosion rate in a postulated abiotic Earth to the present Earth, as well as the activation barrier to diagenetic and metamorphic reactions that affect the water storage capacity of the subducting crust. We find stable and unstable fixed points in

  20. Decreasing µ142Nd Variation in the Archean Convecting Mantle from 4.0 to 2.5 Ga: Heterogeneous Domain Mixing or Crustal Recycling?

    Science.gov (United States)

    Brandon, A. D.; Debaille, V.

    2014-12-01

    The 146Sm-142Nd (t1/2=68 Ma) chronometer can be used to examine silicate differentiation in the first 400 Ma of Earth history. Early fractionation between Sm and Nd is recorded in cratonic Archean rocks in their 142Nd/144Nd ratios that that deviate up to ±20 ppm, or μ142Nd - ppm deviation relative to the present-day convecting mantle at 0. These values likely record early extraction of incompatible trace element (ITE) enriched material with -μ142Nd, either as crust or late stage residual melt from a magma ocean, and resulting in a complimentary ITE depleted residual mantle with +μ142Nd. If this early-formed ITE-enriched material was re-incorporated rapidly back into the convecting mantle, both ITE-enriched and ITE-depleted mantle domains would have been established in the Hadean. Alternatively, if it was early-formed crust that remained stable it could have slowly eroded and progressively remixed into the convecting mantle as subducted sediment during the Archean. Each of these scenarios could potentially explain the decrease in the maximum variation in µ142Nd from ±20 at 4.0 Ga to 0 at 2.5 Ga [1,2,3]. In the scenario where these variations reflect mixing of mantle domains, this implies long mantle mixing times of greater than 1 Ga in the Archean in order to preserve the early-formed heterogeneities. This can be achieved in a stagnant lid tectonic regime in the Archean with sporadic and short subduction cycles [2]. This scenario would also indicate that mixing times in the convecting mantle were much slower than the previously proposed 100 Ma in the Hadean and Archean. In the alternative scenario, sediment with -µ142Nd was progressively mixed into the mantle via subduction in the Archean [3]. This scenario doesn't require slow mantle mixing times or a stagnant-lid regime. It requires crustal resident times of up to 750 Ma to maintain a steady supply of ancient sediment recycling over the Archean. Each of these scenarios evoke very contrasting conditions for

  1. Slab-derived components in the subcontinental lithospheric mantle beneath Chilean Patagonia: Geochemistry and Sr-Nd-Pb isotopes of mantle xenoliths and host basalt

    Science.gov (United States)

    Jalowitzki, Tiago; Gervasoni, Fernanda; Conceição, Rommulo V.; Orihashi, Yuji; Bertotto, Gustavo W.; Sumino, Hirochika; Schilling, Manuel E.; Nagao, Keisuke; Morata, Diego; Sylvester, Paul

    2017-11-01

    modified oceanic crust throughout the initial stages of the Farallón-Aluk ridge collision during Paleocene to Eocene time. However, based on the tectonic evolution of southern South America, we cannot exclude the influence of long-lived subduction events beneath south Patagonia. Although we believe that the studied samples were brought to the surface in this geodynamic context, there is no evidence that ocean island basalt (OIB)-like melts related to the Farallón-Aluk asthenospheric slab window affected the peridotite composition. The host alkaline basalt is a single unit with a HIMU-like OIB signature characterized by marked positive Nb-Ta anomalies coupled with negative anomalies in highly incompatible and fluid-mobile elements (Rb, K, Pb, and Sr). The compositional similarity between the HIMU-like OIB mantle source and the host basalt is also evident from trace element ratios [(Ba-Th-K-La-Zr)/Nb] as well as by the low 87Sr/86Sri (0.703039-0.703058) and relatively high 143Nd/144Ndi (0.512880-0.512874) and 206Pb/204Pb (19.333-19.389) isotopic ratios. The low 206Pb/204Pb ratios compared to end-member HIMU lavas (e.g., Sta. Helena and the Cook-Austral Islands) suggest that this region was modified by processes associated with a prolonged period of subduction related to the Andean orogenesis and the recycling of several oceanic plates beneath the continent, following the Mesozoic breakup of Gondwana or an even older subduction-related event with young recycling ages (< 2 Ga).

  2. Addition of Rituximab to Involved-Field Radiation Therapy Prolongs Progression-free Survival in Stage I-II Follicular Lymphoma: Results of a Multicenter Study

    Energy Technology Data Exchange (ETDEWEB)

    Ruella, Marco [Division of Haematology and Cell Therapy, Mauriziano Hospital and University of Torino, Torino (Italy); Center for Cellular Immunotherapies, Perelman School of Medicine, University of Pennsylvania, Philadelphia (United States); Filippi, Andrea Riccardo [Department of Oncology, Radiation Oncology, University of Torino, Torino (Italy); Bruna, Riccardo [Division of Haematology and Cell Therapy, Mauriziano Hospital and University of Torino, Torino (Italy); Di Russo, Anna [Radiation Oncology, Istituto Nazionale Tumori, Milano (Italy); Magni, Michele [Division of Medical Oncology, Istituto Nazionale Tumori, and University of Milano, Milano (Italy); Caracciolo, Daniele [Division of Haematology, San Giovanni Battista Hospital and University of Torino, Torino (Italy); Passera, Roberto [Division of Nuclear Medicine, San Giovanni Battista Hospital and University of Torino, Torino (Italy); Matteucci, Paola; Di Nicola, Massimo [Division of Medical Oncology, Istituto Nazionale Tumori, and University of Milano, Milano (Italy); Corradini, Paolo [Division of Haematology, Istituto Nazionale Tumori, and University of Milano, Milano (Italy); Parvis, Guido [Division of Haematology, San Luigi Gonzaga Hospital, Orbassano, Torino (Italy); Gini, Guido; Olivieri, Attilio [Division of Haematology, Ospedali Riuniti, Ancona (Italy); Ladetto, Marco [Division of Haematology, San Giovanni Battista Hospital and University of Torino, Torino (Italy); Ricardi, Umberto [Department of Oncology, Radiation Oncology, University of Torino, Torino (Italy); Tarella, Corrado, E-mail: corrado.tarella@gmail.com [Division of Haematology and Cell Therapy, Mauriziano Hospital and University of Torino, Torino (Italy); Hemato-Oncology Division, European Institute of Oncology, Milano (Italy); Devizzi, Liliana [Division of Medical Oncology, Istituto Nazionale Tumori, and University of Milano, Milano (Italy)

    2016-03-15

    Purpose: Rituximab (Rit) therapy added to involved-field radiation therapy (RT) has been proposed as an effective treatment for stage I-II follicular lymphoma (FL). The results of an observational multicenter study on the Rit-RT combination in limited-stage FL are here reported. Methods and Materials: Data have been collected from 2 consecutive cohorts of 94 patients with stage I-II FL treated between 1985 and 2011 at 5 Italian institutions. All patients had grade 1-3a FL, a median age of 54 years (range: 25-82). The first 51 patients received RT alone (control group), while the subsequent series of 43 patients received 4 rituximab courses (375 mg/m{sup 2}, days 1, 8, 15, 22) before RT (Rit-RT). Molecular disease was evaluated by nested bcl-2/IgH PCR or clonal IgH rearrangement was available in 33 Rit-RT patients. Results: At a median follow-up of 10.9 years (range: 1.8-22.9), the 10-year progression-free survival (PFS) and overall survival (OS) projections for the whole cohort were 57% and 87.5%, respectively. The 10-year PFS was significantly longer (P<.05) in the Rit-RT group (64.6%) compared to RT alone (50.7%), whereas the 10-year OS projections were not significantly different. On bivariate analysis controlling for stage, there was only a trend toward improved PFS for Rit-RT (HR, 0.55; P=.081). Follicular lymphoma international prognostic index and age were associated with OS but not with PFS on Cox regression analysis. Bone marrow molecular analysis showing PCR positivity at diagnosis was strongly associated with relapse risk upon univariate and multivariate analysis. Conclusions: This multicenter observational study suggests a potential benefit of adding rituximab to radiation therapy for stage I-II FL. The results of the currently ongoing randomized studies are required to confirm these results. The study underlines the importance of molecular disease monitoring also for patient with limited-stage disease.

  3. Addition of Rituximab to Involved-Field Radiation Therapy Prolongs Progression-free Survival in Stage I-II Follicular Lymphoma: Results of a Multicenter Study

    International Nuclear Information System (INIS)

    Ruella, Marco; Filippi, Andrea Riccardo; Bruna, Riccardo; Di Russo, Anna; Magni, Michele; Caracciolo, Daniele; Passera, Roberto; Matteucci, Paola; Di Nicola, Massimo; Corradini, Paolo; Parvis, Guido; Gini, Guido; Olivieri, Attilio; Ladetto, Marco; Ricardi, Umberto; Tarella, Corrado; Devizzi, Liliana

    2016-01-01

    Purpose: Rituximab (Rit) therapy added to involved-field radiation therapy (RT) has been proposed as an effective treatment for stage I-II follicular lymphoma (FL). The results of an observational multicenter study on the Rit-RT combination in limited-stage FL are here reported. Methods and Materials: Data have been collected from 2 consecutive cohorts of 94 patients with stage I-II FL treated between 1985 and 2011 at 5 Italian institutions. All patients had grade 1-3a FL, a median age of 54 years (range: 25-82). The first 51 patients received RT alone (control group), while the subsequent series of 43 patients received 4 rituximab courses (375 mg/m"2, days 1, 8, 15, 22) before RT (Rit-RT). Molecular disease was evaluated by nested bcl-2/IgH PCR or clonal IgH rearrangement was available in 33 Rit-RT patients. Results: At a median follow-up of 10.9 years (range: 1.8-22.9), the 10-year progression-free survival (PFS) and overall survival (OS) projections for the whole cohort were 57% and 87.5%, respectively. The 10-year PFS was significantly longer (P<.05) in the Rit-RT group (64.6%) compared to RT alone (50.7%), whereas the 10-year OS projections were not significantly different. On bivariate analysis controlling for stage, there was only a trend toward improved PFS for Rit-RT (HR, 0.55; P=.081). Follicular lymphoma international prognostic index and age were associated with OS but not with PFS on Cox regression analysis. Bone marrow molecular analysis showing PCR positivity at diagnosis was strongly associated with relapse risk upon univariate and multivariate analysis. Conclusions: This multicenter observational study suggests a potential benefit of adding rituximab to radiation therapy for stage I-II FL. The results of the currently ongoing randomized studies are required to confirm these results. The study underlines the importance of molecular disease monitoring also for patient with limited-stage disease.

  4. Validation study of a quantitative multigene reverse transcriptase-polymerase chain reaction assay for assessment of recurrence risk in patients with stage II colon cancer.

    Science.gov (United States)

    Gray, Richard G; Quirke, Philip; Handley, Kelly; Lopatin, Margarita; Magill, Laura; Baehner, Frederick L; Beaumont, Claire; Clark-Langone, Kim M; Yoshizawa, Carl N; Lee, Mark; Watson, Drew; Shak, Steven; Kerr, David J

    2011-12-10

    We developed quantitative gene expression assays to assess recurrence risk and benefits from chemotherapy in patients with stage II colon cancer. We sought validation by using RNA extracted from fixed paraffin-embedded primary colon tumor blocks from 1,436 patients with stage II colon cancer in the QUASAR (Quick and Simple and Reliable) study of adjuvant fluoropyrimidine chemotherapy versus surgery alone. A recurrence score (RS) and a treatment score (TS) were calculated from gene expression levels of 13 cancer-related genes (n = 7 recurrence genes and n = 6 treatment benefit genes) and from five reference genes with prespecified algorithms. Cox proportional hazards regression models and log-rank methods were used to analyze the relationship between the RS and risk of recurrence in patients treated with surgery alone and between TS and benefits of chemotherapy. Risk of recurrence was significantly associated with RS (hazard ratio [HR] per interquartile range, 1.38; 95% CI, 1.11 to 1.74; P = .004). Recurrence risks at 3 years were 12%, 18%, and 22% for predefined low, intermediate, and high recurrence risk groups, respectively. T stage (HR, 1.94; P < .001) and mismatch repair (MMR) status (HR, 0.31; P < .001) were the strongest histopathologic prognostic factors. The continuous RS was associated with risk of recurrence (P = .006) beyond these and other covariates. There was no trend for increased benefit from chemotherapy at higher TS (P = .95). The continuous 12-gene RS has been validated in a prospective study for assessment of recurrence risk in patients with stage II colon cancer after surgery and provides prognostic value that complements T stage and MMR. The TS was not predictive of chemotherapy benefit.

  5. Isotope ratios of strontium and neodymium for characterizing earth mantle materials

    International Nuclear Information System (INIS)

    Brandt, S.B.; Lepin, V.S.; Maslovskaja, M.N.

    1985-01-01

    It is shown that the shares of mantle, crustal and sedimentary materials in rocks and ore deposits can be determined by isotope methods. Using Yakutian kimberlites as an example, mixing processes of mantle and crustal materials are illustrated with the aid of strontium isotopes. Due to the high sensitivity of strontium to hydrothermal effects, the combined use of neodymium and strontium isotopes is considered more appropriate to solve the problem of determining the share of mantle materials. This is demonstrated for rare earth minerals and alkaline rocks of Eastern Siberia and Mongolia. (author)

  6. The origin of high-Mg magmas in Mt Shasta and Medicine Lake volcanoes, Cascade Arc (California): higher and lower than mantle oxygen isotope signatures attributed to current and past subduction

    Science.gov (United States)

    Martin, E.; Bindeman, I.; Grove, T. L.

    2011-11-01

    We report the oxygen isotope composition of olivine and orthopyroxene phenocrysts in lavas from the main magma types at Mt Shasta and Medicine Lake Volcanoes: primitive high-alumina olivine tholeiite (HAOT), basaltic andesites (BA), primitive magnesian andesites (PMA), and dacites. The most primitive HAOT (MgO > 9 wt%) from Mt. Shasta has olivine δ18O (δ18OOl) values of 5.9-6.1‰, which are about 1‰ higher than those observed in olivine from normal mantle-derived magmas. In contrast, HAOT lavas from Medicine Lake have δ18OOl values ranging from 4.7 to 5.5‰, which are similar to or lower than values for olivine in equilibrium with mantle-derived magmas. Other magma types from both volcanoes show intermediate δ18OOl values. The oxygen isotope composition of the most magnesian lavas cannot be explained by crustal contamination and the trace element composition of olivine phenocrysts precludes a pyroxenitic mantle source. Therefore, the high and variable δ18OOl signature of the most magnesian samples studied (HAOT and BA) comes from the peridotitic mantle wedge itself. As HAOT magma is generated by anhydrous adiabatic partial melting of the shallow mantle, its 1.4‰ range in δ18OOl reflects a heterogeneous composition of the shallow mantle source that has been influenced by subduction fluids and/or melts sometime in the past. Magmas generated in the mantle wedge by flux melting due to modern subduction fluids, as exemplified by BA and probably PMA, display more homogeneous composition with only 0.5‰ variation. The high-δ18O values observed in magnesian lavas, and principally in the HAOT, are difficult to explain by a single-stage flux-melting process in the mantle wedge above the modern subduction zone and require a mantle source enriched in 18O. It is here explained by flow of older, pre-enriched portions of the mantle through the slab window beneath the South Cascades.

  7. Characterizations of Shell and Mantle Edge Pigmentation of a Pacific Oyster, , in Korean Peninsula

    Directory of Open Access Journals (Sweden)

    Jung-Ha Kang

    2013-12-01

    Full Text Available The objectives of this study were to investigate color patterns of shell and mantle edge pigmentation of a Pacific oyster, C. gigas, and to estimate variance components of the two colors. A sample of 240 F0 oysters was collected from six aquaculture farms in Tongyeong, Korea to measure shell color and mantle edge pigmentation. Among the F0s, male and female individuals with black (white shell and black (white mantle edge were selected and mated to generate three F1 full-sib black (white cross families (N = 265. Two and four F2 cross families (N = 286 were also produced from black and white F1 selected individuals, respectively. Variance component estimates due to residuals and families within color were obtained using SAS PROC VARCOMP procedures to estimate heritability of shell and mantle edge pigmentation. In the F0 generation, about 29% (11% had black (white color for both shell and mantle edge. However, in the F1 and F2 black (white cross families, 75% (67% and 100% (100% of oysters had black (white shell colors, and 59% (23% and 79% (55% had black (white mantle edge, respectively. Spearman correlation coefficients between shell and mantle edge color were 0.25, 0.74, and 0.92 in F0, F1, and F2 generations, respectively, indicating that, with generations of selection process, an individual with black (white shell color is more likely to have black (white mantle edge pigmentation. This suggests that shell color could be a good indicator trait for mantle edge pigmentation if selection of both the colors is implemented for a couple of generations. Estimates of heritability were 0.41 and 0.77 for shell color and 0.27 and 0.08 for mantle edge pigmentation in the F1 and F2 generations, respectively, indicating that, in general, significant proportions of phenotypic variations for the shell and mantle edge colors are explained by genetic variations between individuals. These results suggest that the two color traits are inheritable and correlated

  8. Stages of tuberculous meningitis: a clinicoradiologic analysis

    International Nuclear Information System (INIS)

    Sher, K.; Firdaus, A.; Bullo, N.; Kumar, S.; Abbasi, A.

    2013-01-01

    Objective: To determine the frequencies and percentages of various clinicoradiologic variables of tuberculosis meningitis (TBM) with reference to British Medical Research Council (BMRC) staging of the disease. Study Design: A case series. Place and Duration of Study: Department of Neurology, Jinnah Postgraduate Medical Centre, Karachi, from October 2010 to September 2011. Methodology: The study included 93 adult patients with the diagnosis of tuberculous meningitis (TBM) at the study place. Patients were divided in three groups according to British Medical Research Council (BMRC) staging of TBM. Different clinical and radiological findings were analyzed at different stages of the disease. Data was analyzed using SPSS (Statistical Package of Social Sciences) version 11.0. Results: A majority of patients were found to be in stage-II disease at the time of admission. History of illness at the time of admission was more than 2 weeks in 50% of stage-I patients but around 80% in stage-II and stage-III patients. Neck stiffness was the most commonly reported finding in all stages. Cranial nerve palsies were higher in stage-III (75%) than in stage-II (43%) and in stage-I (24%) patients. Hydrocephalus and basal enhancement was the most frequently reported radiographic abnormalities. Conclusion: Duration of illness and cranial nerve palsies are important variables in the diagnosis of TBM stages and if TBM is suspected, empiric treatment should be started immediately without bacteriologic proof to prevent morbidity and mortality. (author)

  9. The plasma mantle: Composition and other characteristics observed by means of the Prognoz-7 Satellite

    International Nuclear Information System (INIS)

    Pissarenko, N.; Zackarov, A.; Lundin, R.; Hultqvist, B.

    1981-03-01

    PROGNOZ-7 measurements in the nightside plasma mantle are described and analyzed. Some of the results are the following: In the nightside mantle not too far from midnight the properties of the mantle are sometimes consistent with the open magnetosphere model. An exception is found during most magnetic storm situations when 0 + ions appear in the mantle in so large proportions and with so high energies that direct injection of ionospheric ions by acceleration along the magnetic field lines appear to be most likely source mechanism. Along the flanks of the magnetosphere the open magnetosphere model does sometimes not fit at all with the PROGNOZ-7 observations. There the flow of the plasma is often low or absent. The 0 + content is high (up to 20%) and the energy spectrum of both ions and electrons may be very hot, even up to the level of the ring current plasma. Contrary to the predictions of the open magnetosphere model, the magnetopause on the nightside and along the flanks of the magnetosphere appears to be fairly solid boundary for mantle ions of ionospheric origin. An interesting observation in most of the mantle passages during geomagnetically disturbed periods is the occurrence of intense, magnetosheath like, regions deep inside the mantle. In some cases these regions with strong antisunward flow and with predominant magnetosheat ion composition was observed in the innermost part of the mantle, i.e. marking a boundary region between the lobe and the mantle. These magnetosheat ''penetration'' events are usually associated with strong fluxes of accelerated ionospheric ions in nearby parts of the mantle. Evanescent ''penetration'' regions with much reduced flow properties are frequently observed in the flank mantles. (author)

  10. Hydrogen storage in Earth's mantle and core

    Science.gov (United States)

    Prewitt, Charles T.

    1994-01-01

    Two different approaches to explaining how hydrogen might be stored in the mantle are illustrated by a number of papers published over the past 25-30 years, but there has been little attempt to provide objective comparisons of the two. One approach invokes the presence in the mantle of dense hydrous magnesium silicates (DHMS) stable at elevated pressures and temperatures. The other involves nominally anhydrous minerals (NAM) that contain hydrogen as a minor constituent on the ppm level. Experimental studies on DHMS indicate these phases may be stable to pressures and temperatures as high at 16 GPa and 1200 C. This temperature is lower than that indicated by a mantle geotherm at 16 GPa, but may be reasonable for a subducting slab. It is possible that other DHMS could be stable to even higher pressures, but little is known about maximum temperature limits. For NAM, small amounts of hydrogen (up to several hundred ppm) have been detected in olivine, orthopyroxene, clinopyroxene, and garnet recovered from xenoliths in kimberlites, eclogites, and alkali basalts; it has been demonstrated that synthetic wadsleyite and perovskite can accommodate significant amounts of hydrogen. A number of problems are associated with each possibility. For NAM originating in the mantle, one would like to assume that the hydrogen measured in samples recovered on Earth's surface was incorporated when the phase-crystallized at high temperatures and pressures, but it could have been introduced during transport to the surface. Major problems for the DHMS proponents are that none of these phases have been found as minerals and little is yet known about their stabilities in systems containing other cations such as Fe, Al, and Ca.

  11. Extreme Hf and light Fe isotopes in Archean komatiites - a remnant of very early mantle depletion?

    Science.gov (United States)

    Nebel, O.; Sossi, P.; Campbell, I. H.; Van Kranendonk, M. J.

    2014-12-01

    Hafnium isotope signatures in some Archean komatiites (ca. 3.5-3.0 billion years old) require a mantle source with a time-integrated Lu/Hf that exceeds average modern depleted mantle. Investigation of the timing and locus of parent-daughter fractionation in their mantle sources potentially constrains differentiation processes in the early Earth and their subsequent distribution and storage. In addition, they may help to constrain the Hf isotope evolution of the greater depleted mantle. In order to shed light on these processes, we discuss radiogenic Hf isotopes in conjunction with stable Fe isotope systematics in Archean komatiites from the Pilbara craton in Western Australia. Our findings indicate that, after careful evaluation of the effects of alteration, pristine samples are characterised by initial 176Hf/177Hf, which lie above the age-corrected depleted mantle, as a consequence of ancient melt extraction. Iron isotope systematics for these samples further point to a mantle source that is isotopically lighter than average modern depleted mantle, which is also consistent with melt-depletion. Taken together, these observations require a component of an old, super-depleted reservoir in the komatiite mantle source(s) that survived in the mantle for possibly hundreds of millions of years. The Lu/Hf of this refractory mantle appears to be complementary to, and therefore contemporaneous with, the first terrestrial crust, as preserved in Hadean (i.e., > 4 Ga) detrital zircon cores, which may indicate a causal relationship between them. We will discuss implications for very early mantle dynamics and the formation of very early mantle reservoirs.

  12. Fine-scale structure of the mid-mantle characterised by global stacks of PP precursors

    Science.gov (United States)

    Bentham, H. L. M.; Rost, S.; Thorne, M. S.

    2017-08-01

    Subduction zones are likely a major source of compositional heterogeneities in the mantle, which may preserve a record of the subduction history and mantle convection processes. The fine-scale structure associated with mantle heterogeneities can be studied using the scattered seismic wavefield that arrives as coda to or as energy preceding many body wave arrivals. In this study we analyse precursors to PP by creating stacks recorded at globally distributed stations. We create stacks aligned on the PP arrival in 5° distance bins (with range 70-120°) from 600 earthquakes recorded at 193 stations stacking a total of 7320 seismic records. As the energy trailing the direct P arrival, the P coda, interferes with the PP precursors, we suppress the P coda by subtracting a best fitting exponential curve to this energy. The resultant stacks show that PP precursors related to scattering from heterogeneities in the mantle are present for all distances. Lateral variations are explored by producing two regional stacks across the Atlantic and Pacific hemispheres, but we find only negligible differences in the precursory signature between these two regions. The similarity of these two regions suggests that well mixed subducted material can survive at upper and mid-mantle depth. To describe the scattered wavefield in the mantle, we compare the global stacks to synthetic seismograms generated using a Monte Carlo phonon scattering technique. We propose a best-fitting layered heterogeneity model, BRT2017, characterised by a three layer mantle with a background heterogeneity strength (ɛ = 0.8%) and a depth-interval of increased heterogeneity strength (ɛ = 1%) between 1000 km and 1800 km. The scalelength of heterogeneity is found to be 8 km throughout the mantle. Since mantle heterogeneity of 8 km scale may be linked to subducted oceanic crust, the detection of increased heterogeneity at mid-mantle depths could be associated with stalled slabs due to increases in viscosity

  13. Towards modelling of water inflow into the mantle

    Science.gov (United States)

    Thielmann, M.; Eichheimer, P.; Golabek, G.

    2017-12-01

    The transport and storage of water in the mantle significantly affects various material properties of mantle rocks and thus water plays a key role in a variety of geodynamical processes (tectonics, magmatism etc.) Geological and seismological observations suggest different inflow mechanisms of water via the subducting slab like slab bending, thermal cracking and serpentinization (Faccenda et al., 2009; Korenaga, 2017). Most of the previous numerical models do not take different dip angles of the subduction slab and subduction velocities into account, while nature provides two different types of subduction regimes i.e. shallow and deep subduction (Li et al., 2011). To which extent both parameters influence the inflow and outflow of water in the mantle still remains unclear. For the investigation of the inflow and outflow of fluids e.g. water in the mantle, we use high resolution 2D finite element simulations, which allow us to resolve subducted sediments and crustal layers. For this purpose the finite element code MVEP2 (Kaus, 2010), is tested against benchmark results (van Keken et al., 2008). In a first step we reproduced the analytical cornerflow model (Batchelor, 1967) used in the benchmark of van Keken et al.(2008) as well as the steady state temperature field. Further steps consist of successively increasing model complexity, such as the incorporation of hydrogen diffusion, water transport and dehydration reactions. ReferencesBatchelor, G. K. An Introduction to Fluid Dynamics. Cambridge University Press, Cambridge, UK (1967) van Keken, P. E., et al. A community benchmark for subduction zone modeling. Phys. Earth Planet. Int. 171, 187-197 (2008). Faccenda, M., T.V. Gerya, and L. Burlini. Deep slab hydration induced by bending-related variations in tectonic pressure. Nat. Geosci. 2, 790-793 (2009). Korenaga, J. On the extent of mantle hydration caused by plate bending. Earth Planet. Sci. Lett. 457, 1-9 (2017). Li, Z. H., Xu, Z. Q., and T.V. Gerya. Flat versus

  14. Modeling mantle convection in the spherical annulus

    Science.gov (United States)

    Hernlund, John W.; Tackley, Paul J.

    2008-12-01

    Most methods for modeling mantle convection in a two-dimensional (2D) circular annular domain suffer from innate shortcomings in their ability to capture several characteristics of the spherical shell geometry of planetary mantles. While methods such as rescaling the inner and outer radius to reduce anomalous effects in a 2D polar cylindrical coordinate system have been introduced and widely implemented, such fixes may have other drawbacks that adversely affect the outcome of some kinds of mantle convection studies. Here we propose a new approach that we term the "spherical annulus," which is a 2D slice that bisects the spherical shell and is quantitatively formulated at the equator of a spherical polar coordinate system after neglecting terms in the governing equations related to variations in latitude. Spherical scaling is retained in this approximation since the Jacobian function remains proportional to the square of the radius. We present example calculations to show that the behavior of convection in the spherical annulus compares favorably against calculations performed in other 2D annular domains when measured relative to those in a fully three-dimensional (3D) spherical shell.

  15. Hospital-level Variation in Utilization of Surgery for Clinical Stage I-II Pancreatic Adenocarcinoma.

    Science.gov (United States)

    Swords, Douglas S; Mulvihill, Sean J; Skarda, David E; Finlayson, Samuel R G; Stoddard, Gregory J; Ott, Mark J; Firpo, Matthew A; Scaife, Courtney L

    2017-07-11

    To (1) evaluate rates of surgery for clinical stage I-II pancreatic ductal adenocarcinoma (PDAC), (2) identify predictors of not undergoing surgery, (3) quantify the degree to which patient- and hospital-level factors explain differences in hospital surgery rates, and (4) evaluate the association between adjusted hospital-specific surgery rates and overall survival (OS) of patients treated at different hospitals. Curative-intent surgery for potentially resectable PDAC is underutilized in the United States. Retrospective cohort study of patients ≤85 years with clinical stage I-II PDAC in the 2004 to 2014 National Cancer Database. Mixed effects multivariable models were used to characterize hospital-level variation across quintiles of hospital surgery rates. Multivariable Cox proportional hazards models were used to estimate the effect of adjusted hospital surgery rates on OS. Of 58,553 patients without contraindications or refusal of surgery, 63.8% underwent surgery, and the rate decreased from 2299/3528 (65.2%) in 2004 to 4412/7092 (62.2%) in 2014 (P < 0.001). Adjusted hospital rates of surgery varied 6-fold (11.4%-70.9%). Patients treated at hospitals with higher rates of surgery had better unadjusted OS (median OS 10.2, 13.3, 14.2, 16.5, and 18.4 months in quintiles 1-5, respectively, P < 0.001, log-rank). Treatment at hospitals in lower surgery rate quintiles 1-3 was independently associated with mortality [Hazard ratio (HR) 1.10 (1.01, 1.21), HR 1.08 (1.02, 1.15), and HR 1.09 (1.04, 1.14) for quintiles 1-3, respectively, compared with quintile 5] after adjusting for patient factors, hospital type, and hospital volume. Quality improvement efforts are needed to help hospitals with low rates of surgery ensure that their patients have access to appropriate surgery.

  16. Crustal and mantle velocity models of southern Tibet from finite frequency tomography

    Science.gov (United States)

    Liang, Xiaofeng; Shen, Yang; Chen, Yongshun John; Ren, Yong

    2011-02-01

    Using traveltimes of teleseismic body waves recorded by several temporary local seismic arrays, we carried out finite-frequency tomographic inversions to image the three-dimensional velocity structure beneath southern Tibet to examine the roles of the upper mantle in the formation of the Tibetan Plateau. The results reveal a region of relatively high P and S wave velocity anomalies extending from the uppermost mantle to at least 200 km depth beneath the Higher Himalaya. We interpret this high-velocity anomaly as the underthrusting Indian mantle lithosphere. There is a strong low P and S wave velocity anomaly that extends from the lower crust to at least 200 km depth beneath the Yadong-Gulu rift, suggesting that rifting in southern Tibet is probably a process that involves the entire lithosphere. Intermediate-depth earthquakes in southern Tibet are located at the top of an anomalous feature in the mantle with a low Vp, a high Vs, and a low Vp/Vs ratio. One possible explanation for this unusual velocity anomaly is the ongoing granulite-eclogite transformation. Together with the compressional stress from the collision, eclogitization and the associated negative buoyancy force offer a plausible mechanism that causes the subduction of the Indian mantle lithosphere beneath the Higher Himalaya. Our tomographic model and the observation of north-dipping lineations in the upper mantle suggest that the Indian mantle lithosphere has been broken laterally in the direction perpendicular to the convergence beneath the north-south trending rifts and subducted in a progressive, piecewise and subparallel fashion with the current one beneath the Higher Himalaya.

  17. A PROSPECTIVE STUDY ON PREOPERATIVE CONCURRENT CHEMORADIATION WITH CAPECITABINE IN STAGE II/III CARCINOMA OF RECTUM

    Directory of Open Access Journals (Sweden)

    Anish Kuttappan Soman

    2017-09-01

    Full Text Available BACKGROUND Fluorouracil (5-FU based chemoradiotherapy represents the standard treatment option for the preoperative treatment of advanced rectal cancer. Capecitabine is an oral precursor of 5-FU with the advantage of delivering the chemotherapy in an outpatient setup. NSABP R-04 & a German phase 3 trial by Hofheinz et al showed that Capecitabine was equivalent to 5-FU. The primary objective of this study was to evaluate pathological response (PR, clinical & surgical outcomes of stage II & III patients treated with chemoradiation with Capecitabine. The secondary objective was to evaluate toxicity and compliance to treatment. MATERIALS AND METHODS This single arm prospective study included 35 patients with stages II & III adenocarcinoma of rectum who after evaluation were treated with pelvic radiotherapy and concurrent Capecitabine. Toxicities were graded using RTOG scoring criteria. Clinical response was assessed after EBRT completion, and patients were referred for surgery after 4-6 weeks. Pathologic response and completeness of resection were assessed from the histopathology report. RESULTS Growth located within 5 cm from anal verge was seen in 24 (68.5% patients and 6 were inoperable upfront. All patients completed the intended preoperative treatment and 88.6% did not have any toxicity related break in RT. Clinical response was seen in 80% of patients after Chemoradiation. Out of 35 treated 80% of them underwent surgery. APR was performed in 64.2% and 35.7% had LAR. Out of 6 upfront inoperable patients, 3 were converted to operable. Out of 23 APR cases, 7 were converted to anterior resection (30.4%, p=0.046. 96% of operated patients had an R0 resection, including all the 3 upfront inoperable patients. Minimal pathologic response was seen in 89.2% of patients and 7.14% had complete pathologic response. There were no Grade 4 or 5 toxicities. Only 2.9% had a Grade 3 event. 45.7% had maximum of Grade 1 events and 48.6% had maximum of Grade 2

  18. Prognostic implications of occult nodal tumour cells in stage I and II colon cancer: The correlation between micrometastasis and disease recurrence

    NARCIS (Netherlands)

    Sloothaak, D. A. M.; van der Linden, R. L. A.; van de Velde, C. J. H.; Bemelman, W. A.; Lips, D. J.; van der Linden, J. C.; Doornewaard, H.; Tanis, P. J.; Bosscha, K.; van der Zaag, E. S.; Buskens, C. J.

    2017-01-01

    Occult nodal tumour cells should be categorised as micrometastasis (MMs) and isolated tumour cells (ITCs). A recent meta-analysis demonstrated that MMs, but not ITCs, are prognostic for disease recurrence in patients with stage I/II colon cancer. The objective of this retrospective multicenter study

  19. Partial delamination of continental mantle lithosphere, uplift-related crust mantle decoupling, volcanism and basin formation: a new model for the Pliocene Quaternary evolution of the southern East-Carpathians, Romania

    Science.gov (United States)

    Chalot-Prat, F.; Girbacea, R.

    2000-11-01

    A geodynamic model is proposed for the Mid-Miocene to Quaternary evolution of the southern East-Carpathians in order to explain the relationships between shallow and deep geological phenomena that occurred synchronously during late-collision tectonics. In this area, an active volcanic zone cross-cuts since 2 My the suture between the overriding Tisza-Dacia and subducting European continental plates. Mafic calc-alkaline and alkaline magmas (south Harghita and Persani volcanoes) erupted contemporaneously. These magmas were supplied by partial melting of the mantle lithosphere of the subducting, and not of the overriding, plate. In an effort to decipher this geodynamically a-typical setting of magma generation, the spatial and temporal distribution of shallow and deep phenomena was successively examined in order to establish the degree of their interdependence. Our model indicates that intra-mantle delamination of the subducting European plate is the principal cause of a succession of events. It caused upwelling of the hot asthenosphere below a thinned continental lithosphere of the Carpathians, inducing the uplift of the lithosphere and its internal decoupling at the Moho level by isostatic and mostly thermal effects. During this uplift, the crust deformed flexurally whilst the mantle deformed in a ductile way. This triggered decompressional partial melting of the uppermost mantle lithosphere. Flexural deformation of the crust induced its fracturing, allowing for the rapid ascent of magmas to the surface, as well as reactivation of an older detachment horizon at the base of the Carpathian nappe stack above which the Brasov, Ciuc and Gheorghieni hinterland basins formed by extension and gravity spreading. The rapid subsidence of the Focsani foreland basin is controlled by the load exerted on the lithosphere by the delaminated mantle slab that is still attached to it. In this model, crust-mantle decoupling, magma genesis and volcanism, local near-surface hinterland

  20. Mantle hydration along outer-rise faults inferred from serpentinite permeability.

    Science.gov (United States)

    Hatakeyama, Kohei; Katayama, Ikuo; Hirauchi, Ken-Ichi; Michibayashi, Katsuyoshi

    2017-10-24

    Recent geophysical surveys indicate that hydration (serpentinization) of oceanic mantle is related to outer-rise faulting prior to subduction. The serpentinization of oceanic mantle influences the generation of intermediate-depth earthquakes and subduction water flux, thereby promoting arc volcanism. Since the chemical reactions that produce serpentinite are geologically rapid at low temperatures, the flux of water delivery to the reaction front appears to control the lateral extent of serpentinization. In this study, we measured the permeability of low-temperature serpentinites composed of lizardite and chrysotile, and calculated the lateral extent of serpentinization along an outer-rise fault based on Darcy's law. The experimental results indicate that serpentinization extends to a region several hundred meters wide in the direction normal to the outer-rise fault in the uppermost oceanic mantle. We calculated the global water flux carried by serpentinized oceanic mantle ranging from 1.7 × 10 11 to 2.4 × 10 12  kg/year, which is comparable or even higher than the water flux of hydrated oceanic crust.

  1. Effects of grain size evolution on mantle dynamics

    Science.gov (United States)

    Schulz, Falko; Tosi, Nicola; Plesa, Ana-Catalina; Breuer, Doris

    2016-04-01

    The rheology of planetary mantle materials is strongly dependent on temperature, pressure, strain-rate, and grain size. In particular, the rheology of olivine, the most abundant mineral of the Earth's upper mantle, has been extensively studied in the laboratory (e.g., Karato and Wu, 1993; Hirth and Kohlstedt, 2003). Two main mechanisms control olivine's deformation: dislocation and diffusion creep. While the former implies a power-law dependence of the viscosity on the strain-rate that leads to a non-Newtonian behaviour, the latter is sensitively dependent on the grain size. The dynamics of planetary interiors is locally controlled by the deformation mechanism that delivers the lowest viscosity. Models of the dynamics and evolution of planetary mantles should thus be capable to self-consistently distinguish which of the two mechanisms dominates at given conditions of temperature, pressure, strain-rate and grain size. As the grain size can affect the viscosity associated with diffusion creep by several orders of magnitude, it can strongly influence the dominant deformation mechanism. The vast majority of numerical, global-scale models of mantle convection, however, are based on the use of a linear diffusion-creep rheology with constant grain-size. Nevertheless, in recent studies, a new equation has been proposed to properly model the time-dependent evolution of the grain size (Austin and Evens, 2007; Rozel et al., 2010). We implemented this equation in our mantle convection code Gaia (Hüttig et al., 2013). In the framework of simple models of stagnant lid convection, we compared simulations based on the fully time-dependent equation of grain-size evolution with simulations based on its steady-state version. In addition, we tested a number of different parameters in order to identify those that affects the grain size to the first order and, in turn, control the conditions at which mantle deformation is dominated by diffusion or dislocation creep. References Austin

  2. Radiation therapy for stage I-II non-small cell lung cancer in patients aged 75 years and older

    International Nuclear Information System (INIS)

    Furuta, Masaya; Hayakawa, Kazushige; Katano, Susumu

    1996-01-01

    Between 1976 and 1992, 32 patients aged 75 and older with stage I-II non-small cell lung cancer (NSCLC) were given definitive radiation therapy. These patients did not undergo surgery because of old age, poor cardiac/pulmonary condition, or refusal to give consent. The mean age was 79 years, and 11 patients were over 80 years old. The histologic type was squamous cell carcinoma in 25 patients and adenocarcinoma in 7. The clinical T and N stage was T1N0 in 4 patients, T2N0 in 9, and T2N0 in 19. The total dose of radiation therapy given to each patient exceeded 60 Gy using 10-MV X-rays. The treatment was completed in all 32 patients without treatment-related complications. The 2- and 5-year overall actuarial survival rates were 40% and 16%, respectively. Eleven intercurrent deaths occurred, including 7 patients who died of heart disease. The 2- and 5-year cause-specific survival rates were 57% and 36%, respectively. None of the patients developed severe pneumonitis requiring hospitalization. All but three patients received radiation therapy on an inpatient basis. The mean duration of the hospital stay for initial treatment was 56 days, and mean ratio to total survival period (mean 739 days) was 8%. Although many elderly patients have concurrent medical complications such as heart disease and chronic pulmonary disease, the present study showed that elderly patients with clinical stage I-II NSCLC can expert a realistic probability of long-term survival with definitive radiation therapy. (author)

  3. An application of GOCE satellite gravity to resolve mantle heterogeneity in Europe

    DEFF Research Database (Denmark)

    Herceg, Matija; Artemieva, Irina; Thybo, Hans

    2015-01-01

    The aim of this study is to obtain new information on the density structure of the European upper mantle by incorporating the state-of-the-art global gravity data derived from the GOCE satellite gravity mission and recently released seismic model for the crustal structure, EUNAseis. The residual ...... by seismic tomography. Furthermore, we compare our regional upper mantle density model with petrological studies of mantle-derived xenoliths from the Baltic shield and the Arkhangelsk region.......The aim of this study is to obtain new information on the density structure of the European upper mantle by incorporating the state-of-the-art global gravity data derived from the GOCE satellite gravity mission and recently released seismic model for the crustal structure, EUNAseis. The residual...

  4. Update on the Search for Chemical Interactions Between the Core and Mantle

    Science.gov (United States)

    Walker, R. J.

    2017-12-01

    Recent tomographic studies provide strong geophysical evidence for deep mantle upwellings, commonly referred to as "plumes", rising from the core-mantle boundary to regions underlying some ocean island basalt occurrences. Nevertheless, the existence of plumes and their association with ocean islands remains questioned by some. In addition, the occurrence and extent of chemical exchange between the core and lowermost mantle remains essentially un-constrained. If some plumes rise from the core-mantle boundary and there has been some level of chemical interaction between the core and mantle at some point in time, then it is possible that plumes could contain a unique chemical or isotopic fingerprint that is characteristic of the core. There is currently no strong evidence supporting this possibility. The short-lived 182Hf→182W (t½ = 9 m.y.) system has been proposed as a geochemical tool for detecting possible core-mantle interactions. Mass balance constraints suggest the 182W/184W and W concentration of the core are 200 ppm lower and 20 times higher, respectively, than the bulk silicate Earth. Recent discovery of negative correlations between 182W/184W and 3He/4He in ocean island basalts (OIB) from Hawaii and Samoa suggests that these volcanic systems may access a primordial component inside the Earth with W-He isotopic characteristics broadly consistent with the core. However, direct contribution of metal from the outer core to a rising plume is inconsistent with the concentrations of highly siderophile elements (HSE) in the isotopically anomalous lavas. In order for the isotopically anomalous W and He to be tied to the core, a transfer mechanism for isotopic signal, other than metal infiltration into the mantle is needed, as is a present day storage site for the signal. The possible existence of one or more basal magma oceans at some points in Earth history present opportunity for isotopic exchange between the lowermost mantle and core, without collateral

  5. Passive margins getting squeezed in the mantle convection vice

    Science.gov (United States)

    Yamato, Philippe; Husson, Laurent; Becker, Thorsten W.; Pedoja, Kevin

    2014-05-01

    Passive margins often exhibit uplift, exhumation and tectonic inversion. We speculate that the compression in the lithosphere gradually increased during the Cenozoic. In the same time, the many mountain belts at active margins that accompany this event seem readily witness this increase. However, how that compression increase affects passive margins remains unclear. In order to address this issue, we design a 2D viscous numerical model wherein a lithospheric plate rests above a weaker mantle. It is driven by a mantle conveyor belt, alternatively excited by a lateral downwelling on one side, an upwelling on the other side, or both simultaneously. The lateral edges of the plate are either free or fixed, representing the cases of free convergence, and collision or slab anchoring, respectively. This distinction changes the upper boundary condition for mantle circulation and, as a consequence, the stress field. Our results show that between these two regimes, the flow pattern transiently evolves from a free-slip convection mode towards a no-slip boundary condition above the upper mantle. In the second case, the lithosphere is highly stressed horizontally and deforms. For an equivalent bulk driving force, compression increases drastically at passive margins provided that upwellings are active. Conversely, if downwellings alone are activated, compression occurs at short distances from the trench and extension prevails elsewhere. These results are supported by Earth-like 3D spherical models that reveal the same pattern, where active upwellings are required to excite passive margins compression. These results support the idea that compression at passive margins, is the response to the underlying mantle flow, that is increasingly resisted by the Cenozoic collisions.

  6. Bending-related faulting and mantle serpentinization at the Middle America trench.

    Science.gov (United States)

    Ranero, C R; Morgan, J Phipps; McIntosh, K; Reichert, C

    2003-09-25

    The dehydration of subducting oceanic crust and upper mantle has been inferred both to promote the partial melting leading to arc magmatism and to induce intraslab intermediate-depth earthquakes, at depths of 50-300 km. Yet there is still no consensus about how slab hydration occurs or where and how much chemically bound water is stored within the crust and mantle of the incoming plate. Here we document that bending-related faulting of the incoming plate at the Middle America trench creates a pervasive tectonic fabric that cuts across the crust, penetrating deep into the mantle. Faulting is active across the entire ocean trench slope, promoting hydration of the cold crust and upper mantle surrounding these deep active faults. The along-strike length and depth of penetration of these faults are also similar to the dimensions of the rupture area of intermediate-depth earthquakes.

  7. Cephalometric evaluation of the effects of the Twin Block appliance in subjects with Class II, Division 1 malocclusion amongst different cervical vertebral maturation stages

    Directory of Open Access Journals (Sweden)

    Aisha Khoja

    Full Text Available ABSTRACT Objectives: To evaluate the cephalometric changes in skeletal, dentoalveolar and soft tissue variables induced by Clark's Twin Block (CTB in Class II, Division 1 malocclusion patients and to compare these changes in different cervical vertebral maturation stages. Methods: Pre- and post-treatment/observation lateral cephalograms of 53 Class II, Division 1 malocclusion patients and 60 controls were compared to evaluate skeletal, dentoalveolar and soft tissue changes. Skeletal maturity was assessed according to cervical vertebral maturation stages. Pre- and post-treatment/observation mean changes and differences (T2-T1 were compared by means of Wilcoxon sign rank and Mann-Whitney U-tests, respectively. Intergroup comparisons between different cervical stages were performed by means of Kruskal-Wallis test and Mann-Whitney U-test (p ≤ 0.05 . Results: When compared with controls, there was a significant reduction in ANB angle (p < 0.001, which was due to a change in SNB angle in CS-2 and CS-3 (p < 0.001, and in SNA (p < 0.001 and SNB (p = 0.016 angles in the CS-4 group. There was significant increase in the GoGn-SN angle in CS-2 (p = 0.007 and CS-4 (p = 0.024, and increase in Co-Gn and Go-Gn amongst all cervical stages (p < 0.05. There was significant decrease in U1-SN and increase in IMPA amongst all cervical stages (p < 0.05. There was significant retraction of the upper lip in CS-3 (p = 0.001, protrusion of the lower lip in CS-2 (p = 0.005, increase in nasolabial angle in CS-4 (p = 0.006 and Z-angle in CS-3 (p = 0.016, reduction in H-angle in CS-2 (p = 0.013 and CS-3 (p = 0.002 groups. When pre- and post-treatment mean differences were compared between different cervical stages, significant differences were found for SNA, SNB and UI-SN angles and overjet. . Conclusions: The Twin-Block along with the normal craniofacial growth improves facial esthetics in Class II, Division 1 malocclusion by changes in underlying skeletal and

  8. Magnetic field reversals, polar wander, and core-mantle coupling.

    Science.gov (United States)

    Courtillot, V; Besse, J

    1987-09-04

    True polar wander, the shifting of the entire mantle relative to the earth's spin axis, has been reanalyzed. Over the last 200 million years, true polar wander has been fast (approximately 5 centimeters per year) most of the time, except for a remarkable standstill from 170 to 110 million years ago. This standstill correlates with a decrease in the reversal frequency of the geomagnetic field and episodes of continental breakup. Conversely, true polar wander is high when reversal frequency increases. It is proposed that intermittent convection modulates the thickness of a thermal boundary layer at the base of the mantle and consequently the core-to-mantle heat flux. Emission of hot thermals from the boundary layer leads to increases in mantle convection and true polar wander. In conjunction, cold thermals released from a boundary layer at the top of the liquid core eventually lead to reversals. Changes in the locations of subduction zones may also affect true polar wander. Exceptional volcanism and mass extinctions at the Cretaceous-Tertiary and Permo-Triassic boundaries may be related to thermals released after two unusually long periods with no magnetic reversals. These environmental catastrophes may therefore be a consequence of thermal and chemical couplings in the earth's multilayer heat engine rather than have an extraterrestrial cause.

  9. Water contents of clinopyroxenes from sub-arc mantle peridotites

    Science.gov (United States)

    Turner, Michael; Turner, Simon; Blatter, Dawnika; Maury, Rene; Perfit, Michael; Yogodzinski, Gene

    2017-01-01

    One poorly constrained reservoir of the Earth's water budget is that of clinopyroxene in metasomatised, mantle peridotites. This study presents reconnaissance Sensitive High-Resolution, Ion Microprobe–Stable Isotope (SHRIMP–SI) determinations of the H2O contents of (dominantly) clinopyroxenes in rare mantle xenoliths from four different subduction zones, i.e. Mexico, Kamchatka, Philippines, and New Britain (Tabar-Feni island chain) as well as one intra-plate setting (western Victoria). All of the sub-arc xenoliths have been metasomatised and carry strong arc trace element signatures. Average measured H2O contents of the pyroxenes range from 70 ppm to 510 ppm whereas calculated bulk H2O contents range from 88 ppm to 3 737 ppm if the variable presence of amphibole is taken into account. In contrast, the intra-plate, continental mantle xenolith from western Victoria has higher water contents (3 447 ppm) but was metasomatised by alkali and/or carbonatitic melts and does not carry a subduction-related signature. Material similar to the sub-arc peridotites can either be accreted to the base of the lithosphere or potentially be transported by convection deeper into the mantle where it will lose water due to amphibole breakdown.

  10. Molybdenum isotope fractionation in the mantle

    Science.gov (United States)

    Liang, Yu-Hsuan; Halliday, Alex N.; Siebert, Chris; Fitton, J. Godfrey; Burton, Kevin W.; Wang, Kuo-Lung; Harvey, Jason

    2017-02-01

    We report double-spike molybdenum (Mo) isotope data for forty-two mafic and fifteen ultramafic rocks from diverse locations and compare these with results for five chondrites. The δ98/95Mo values (normalized to NIST SRM 3134) range from -0.59 ± 0.04 to +0.10 ± 0.08‰. The compositions of one carbonaceous (CI) and four ordinary chondrites are relatively uniform (-0.14 ± 0.01‰, 95% ci (confidence interval)) in excellent agreement with previous data. These values are just resolvable from the mean of 10 mid-ocean ridge basalts (MORBs) (0.00 ± 0.02‰, 95% ci). The compositions of 13 mantle-derived ultramafic xenoliths from Kilbourne Hole, Tariat and Vitim are more diverse (-0.39 to -0.07‰) with a mean of -0.22 ± 0.06‰ (95% ci). On this basis, the isotopic composition of the bulk silicate Earth (BSE or Primitive Mantle) is within error identical to chondrites. The mean Mo concentration of the ultramafic xenoliths (0.19 ± 0.07 ppm, 95% ci) is similar in magnitude to that of MORB (0.48 ± 0.13 ppm, 95% ci), providing evidence, either for a more compatible behaviour than previously thought or for selective Mo enrichment of the subcontinental lithospheric mantle. Intraplate and ocean island basalts (OIBs) display significant isotopic variability within a single locality from MORB-like to strongly negative (-0.59 ± 0.04‰). The most extreme values measured are for nephelinites from the Cameroon Line and Trinidade, which also have anomalously high Ce/Pb and low Mo/Ce relative to normal oceanic basalts. δ98/95Mo correlates negatively with Ce/Pb and U/Pb, and positively with Mo/Ce, explicable if a phase such as an oxide or a sulphide liquid selectively retains isotopically heavy Mo in the mantle and fractionates its isotopic composition in low degree partial melts. If residual phases retain Mo during partial melting, it is possible that the [Mo] for the BSE may be misrepresented by values estimated from basalts. This would be consistent with the high Mo

  11. Waves in the core and mechanical core-mantle interactions

    DEFF Research Database (Denmark)

    Jault, D.; Finlay, Chris

    2015-01-01

    This Chapter focuses on time-dependent uid motions in the core interior, which can beconstrained by observations of the Earth's magnetic eld, on timescales which are shortcompared to the magnetic diusion time. This dynamics is strongly inuenced by the Earth's rapid rotation, which rigidies...... the motions in the direction parallel to the Earth'srotation axis. This property accounts for the signicance of the core-mantle topography.In addition, the stiening of the uid in the direction parallel to the rotation axis gives riseto a magnetic diusion layer attached to the core-mantle boundary, which would...... otherwisebe dispersed by Alfven waves. This Chapter complements the descriptions of large-scaleow in the core (8.04), of turbulence in the core (8.06) and of core-mantle interactions(8.12), which can all be found in this volume. We rely on basic magnetohydrodynamictheory, including the derivation...

  12. A wet, heterogeneous lunar interior: Lower mantle and core dynamo evolution

    Science.gov (United States)

    Evans, A. J.; Zuber, M. T.; Weiss, B. P.; Tikoo, S. M.

    2014-05-01

    While recent analyses of lunar samples indicate the Moon had a core dynamo from at least 4.2-3.56 Ga, mantle convection models of the Moon yield inadequate heat flux at the core-mantle boundary to sustain thermal core convection for such a long time. Past investigations of lunar dynamos have focused on a generally homogeneous, relatively dry Moon, while an initial compositionally stratified mantle is the expected consequence of a postaccretionary lunar magma ocean. Furthermore, recent re-examination of Apollo samples and geophysical data suggests that the Moon contains at least some regions with high water content. Using a finite element model, we investigate the possible consequences of a heterogeneously wet, compositionally stratified interior for the evolution of the Moon. We find that a postoverturn model of mantle cumulates could result in a core heat flux sufficiently high to sustain a dynamo through 2.5 Ga and a maximum surface, dipolar magnetic field strength of less than 1 μT for a 350-km core and near ˜2 μT for a 450-km core. We find that if water was transported or retained preferentially in the deep interior, it would have played a significant role in transporting heat out of the deep interior and reducing the lower mantle temperature. Thus, water, if enriched in the lower mantle, could have influenced core dynamo timing by over 1.0 Gyr and enhanced the vigor of a lunar core dynamo. Our results demonstrate the plausibility of a convective lunar core dynamo even beyond the period currently indicated by the Apollo samples.

  13. The signal of mantle anisotropy in the coupling of normal modes

    Science.gov (United States)

    Beghein, Caroline; Resovsky, Joseph; van der Hilst, Robert D.

    2008-12-01

    We investigate whether the coupling of normal mode (NM) multiplets can help us constrain mantle anisotropy. We first derive explicit expressions of the generalized structure coefficients of coupled modes in terms of elastic coefficients, including the Love parameters describing radial anisotropy and the parameters describing azimuthal anisotropy (Jc, Js, Kc, Ks, Mc, Ms, Bc, Bs, Gc, Gs, Ec, Es, Hc, Hs, Dc and Ds). We detail the selection rules that describe which modes can couple together and which elastic parameters govern their coupling. We then focus on modes of type 0Sl - 0Tl+1 and determine whether they can be used to constrain mantle anisotropy. We show that they are sensitive to six elastic parameters describing azimuthal anisotropy, in addition to the two shear-wave elastic parameters L and N (i.e. VSV and VSH). We find that neither isotropic nor radially anisotropic mantle models can fully explain the observed degree two signal. We show that the NM signal that remains after correction for the effect of the crust and mantle radial anisotropy can be explained by the presence of azimuthal anisotropy in the upper mantle. Although the data favour locating azimuthal anisotropy below 400km, its depth extent and distribution is still not well constrained by the data. Consideration of NM coupling can thus help constrain azimuthal anisotropy in the mantle, but joint analyses with surface-wave phase velocities is needed to reduce the parameter trade-offs and improve our constraints on the individual elastic parameters and the depth location of the azimuthal anisotropy.

  14. Hydration-reduced lattice thermal conductivity of olivine in Earth's upper mantle.

    Science.gov (United States)

    Chang, Yun-Yuan; Hsieh, Wen-Pin; Tan, Eh; Chen, Jiuhua

    2017-04-18

    Earth's water cycle enables the incorporation of water (hydration) in mantle minerals that can influence the physical properties of the mantle. Lattice thermal conductivity of mantle minerals is critical for controlling the temperature profile and dynamics of the mantle and subducting slabs. However, the effect of hydration on lattice thermal conductivity remains poorly understood and has often been assumed to be negligible. Here we have precisely measured the lattice thermal conductivity of hydrous San Carlos olivine (Mg 0.9 Fe 0.1 ) 2 SiO 4 (Fo90) up to 15 gigapascals using an ultrafast optical pump-probe technique. The thermal conductivity of hydrous Fo90 with ∼7,000 wt ppm water is significantly suppressed at pressures above ∼5 gigapascals, and is approximately 2 times smaller than the nominally anhydrous Fo90 at mantle transition zone pressures, demonstrating the critical influence of hydration on the lattice thermal conductivity of olivine in this region. Modeling the thermal structure of a subducting slab with our results shows that the hydration-reduced thermal conductivity in hydrated oceanic crust further decreases the temperature at the cold, dry center of the subducting slab. Therefore, the olivine-wadsleyite transformation rate in the slab with hydrated oceanic crust is much slower than that with dry oceanic crust after the slab sinks into the transition zone, extending the metastable olivine to a greater depth. The hydration-reduced thermal conductivity could enable hydrous minerals to survive in deeper mantle and enhance water transportation to the transition zone.

  15. Influence of mantle anelasticity on the phase and amplitude of earth tides

    Science.gov (United States)

    Bodri, B.; Pedersen, G. P. H.

    1980-05-01

    The effect of the anelasticity of the mantle on the phase and amplitude of earth tides is calculated for recent models of the internal structure of the earth and its rheological characteristics. The anelastic properties of the mantle are modeled by the Maxwell and Knopoff-Lomnitz rheological bodies. For numerical calculations two different methods of solution are used. Results indicate that the effect of mantle anelasticity on tidal amplitudes is practically zero. For both types of rheological models the phase shifts of the functions characterizing solid tides are small, none of them exceeding values of some minutes of arc. These phase shifts have a very weak dependence on the variation of attenuation and viscosity within the mantle. The present study is closely related to an important problem: what proportion of the observed tidal friction arises not in the ocean but is due to the anelasticity of the mantle. The results suggest that dissipation by solid friction at present is an insignificant, almost negligible component of tidal energy sink.

  16. Methylation of WNT target genes AXIN2 and DKK1 as robust biomarkers for recurrence prediction in stage II colon cancer

    NARCIS (Netherlands)

    Kandimalla, R.; Linnekamp, J. F.; van Hooff, S.; Castells, A.; Llor, X.; Andreu, M.; Jover, R.; Goel, A.; Medema, J. P.

    2017-01-01

    Stage II colon cancer (CC) still remains a clinical challenge with patient stratification for adjuvant therapy (AT) largely relying on clinical parameters. Prognostic biomarkers are urgently needed for better stratification. Previously, we have shown that WNT target genes AXIN2, DKK1, APCDD1, ASCL2

  17. The 2016 Case for Mantle Plumes and a Plume-Fed Asthenosphere (Augustus Love Medal Lecture)

    Science.gov (United States)

    Morgan, Jason P.

    2016-04-01

    The process of science always returns to weighing evidence and arguments for and against a given hypothesis. As hypotheses can only be falsified, never universally proved, doubt and skepticism remain essential elements of the scientific method. In the past decade, even the hypothesis that mantle plumes exist as upwelling currents in the convecting mantle has been subject to intense scrutiny; from geochemists and geochronologists concerned that idealized plume models could not fit many details of their observations, and from seismologists concerned that mantle plumes can sometimes not be 'seen' in their increasingly high-resolution tomographic images of the mantle. In the place of mantle plumes, various locally specific and largely non-predictive hypotheses have been proposed to explain the origins of non-plate boundary volcanism at Hawaii, Samoa, etc. In my opinion, this debate has now passed from what was initially an extremely useful restorative from simply 'believing' in the idealized conventional mantle plume/hotspot scenario to becoming an active impediment to our community's ability to better understand the dynamics of the solid Earth. Having no working hypothesis at all is usually worse for making progress than having an imperfect and incomplete but partially correct one. There continues to be strong arguments and strong emerging evidence for deep mantle plumes. Furthermore, deep thermal plumes should exist in a mantle that is heated at its base, and the existence of Earth's (convective) geodynamo clearly indicates that heat flows from the core to heat the mantle's base. Here I review recent seismic evidence by French, Romanowicz, and coworkers that I feel lends strong new observational support for the existence of deep mantle plumes. I also review recent evidence consistent with the idea that secular core cooling replenishes half the mantle's heat loss through its top surface, e.g. that the present-day mantle is strongly bottom heated. Causes for

  18. Noble gas composition of subcontinental lithospheric mantle: An extensively degassed reservoir beneath Southern Patagonia

    Science.gov (United States)

    Jalowitzki, Tiago; Sumino, Hirochika; Conceição, Rommulo V.; Orihashi, Yuji; Nagao, Keisuke; Bertotto, Gustavo W.; Balbinot, Eduardo; Schilling, Manuel E.; Gervasoni, Fernanda

    2016-09-01

    Patagonia, in the Southern Andes, is one of the few locations where interactions between the oceanic and continental lithosphere can be studied due to subduction of an active spreading ridge beneath the continent. In order to characterize the noble gas composition of Patagonian subcontinental lithospheric mantle (SCLM), we present the first noble gas data alongside new lithophile (Sr-Nd-Pb) isotopic data for mantle xenoliths from Pali-Aike Volcanic Field and Gobernador Gregores, Southern Patagonia. Based on noble gas isotopic compositions, Pali-Aike mantle xenoliths represent intrinsic SCLM with higher (U + Th + K)/(3He, 22Ne, 36Ar) ratios than the mid-ocean ridge basalt (MORB) source. This reservoir shows slightly radiogenic helium (3He/4He = 6.84-6.90 RA), coupled with a strongly nucleogenic neon signature (mantle source 21Ne/22Ne = 0.085-0.094). The 40Ar/36Ar ratios vary from a near-atmospheric ratio of 510 up to 17700, with mantle source 40Ar/36Ar between 31100-6800+9400 and 54000-9600+14200. In addition, the 3He/22Ne ratios for the local SCLM endmember, at 12.03 ± 0.15 to 13.66 ± 0.37, are higher than depleted MORBs, at 3He/22Ne = 8.31-9.75. Although asthenospheric mantle upwelling through the Patagonian slab window would result in a MORB-like metasomatism after collision of the South Chile Ridge with the Chile trench ca. 14 Ma, this mantle reservoir could have remained unhomogenized after rapid passage and northward migration of the Chile Triple Junction. The mantle endmember xenon isotopic ratios of Pali-Aike mantle xenoliths, which is first defined for any SCLM-derived samples, show values indistinguishable from the MORB source (129Xe/132Xe =1.0833-0.0053+0.0216 and 136Xe/132Xe =0.3761-0.0034+0.0246). The noble gas component observed in Gobernador Gregores mantle xenoliths is characterized by isotopic compositions in the MORB range in terms of helium (3He/4He = 7.17-7.37 RA), but with slightly nucleogenic neon (mantle source 21Ne/22Ne = 0.065-0.079). We

  19. Numerical modelling of volatiles in the deep mantle

    Science.gov (United States)

    Eichheimer, Philipp; Thielmann, Marcel; Golabek, Gregor J.

    2017-04-01

    The transport and storage of water in the mantle significantly affects several material properties of mantle rocks and thus water plays a key role in a variety of geodynamical processes (tectonics, magmatism etc.). The processes driving transport and circulation of H2O in subduction zones remain a debated topic. Geological and seismological observations suggest different inflow mechanisms of water e.g. slab bending, thermal cracking and serpentinization (Faccenda et al., 2009; Korenaga, 2017), followed by dehydration of the slab. On Earth both shallow and steep subduction can be observed (Li et al., 2011). However most previous models (van Keken et al., 2008; Wilson et al., 2014) did not take different dip angles and subduction velocities of slabs into account. To which extent these parameters and processes influence the inflow of water still remains unclear. We present 2D numerical models simulating the influence of the various water inflow mechanisms on the mantle with changing dip angle and subduction velocity of the slab over time. The results are used to make predictions regarding the rheological behavior of the mantle wedge, dehydration regimes and volcanism at the surface. References: van Keken, P. E., et al. A community benchmark for subduction zone modeling. Phys. Earth Planet. Int. 171, 187-197 (2008). Faccenda, M., T.V. Gerya, and L. Burlini. Deep slab hydration induced by bending-related variations in tectonic pressure. Nat. Geosci. 2, 790-793 (2009). Korenaga, J. On the extent of mantle hydration caused by plate bending. Earth Planet. Sci. Lett. 457, 1-9 (2017). Wilson, C. R., et al. Fluid flow in subduction zones: The role of solid rheology and compaction pressure. Earth Planet. Sci. Lett. 401, 261-274 (2014). Li, Z. H., Z. Q. Xu, and T. V. Gerya. Flat versus steep subduction: Contrasting modes for the formation and exhumation of high- to ultrahigh-pressure rocks in continental collision zones. Earth Planet. Sci. Lett. 301, 65-77 (2011).

  20. Ancient mantle in a modern arc: osmium isotopes in izu-bonin-mariana forearc peridotites

    Science.gov (United States)

    Parkinson; Hawkesworth; Cohen

    1998-09-25

    Mantle peridotites drilled from the Izu-Bonin-Mariana forearc have unradiogenic 187Os/188Os ratios (0.1193 to 0.1273), which give Proterozoic model ages of 820 to 1230 million years ago. If these peridotites are residues from magmatism during the initiation of subduction 40 to 48 million years ago, then the mantle that melted was much more depleted in incompatible elements than the source of mid-ocean ridge basalts (MORB). This result indicates that osmium isotopes record information about ancient melting events in the convecting upper mantle not recorded by incompatible lithophile isotope tracers. Subduction zones may be a graveyard for ancient depleted mantle material, and portions of the convecting upper mantle may be less radiogenic in osmium isotopes than previously recognized.

  1. The effect of ilmenite viscosity on the dynamics and evolution of an overturned lunar cumulate mantle

    Science.gov (United States)

    Zhang, Nan; Dygert, Nick; Liang, Yan; Parmentier, E. M.

    2017-07-01

    Lunar cumulate mantle overturn and the subsequent upwelling of overturned mantle cumulates provide a potential framework for understanding the first-order thermochemical evolution of the Moon. Upwelling of ilmenite-bearing cumulates (IBCs) after the overturn has a dominant influence on the dynamics and long-term thermal evolution of the lunar mantle. An important parameter determining the stability and convective behavior of the IBC is its viscosity, which was recently constrained through rock deformation experiments. To examine the effect of IBC viscosity on the upwelling of overturned lunar cumulate mantle, here we conduct three-dimensional mantle convection models with an evolving core superposed by an IBC-rich layer, which resulted from mantle overturn after magma ocean solidification. Our modeling shows that a reduction of mantle viscosity by 1 order of magnitude, due to the presence of ilmenite, can dramatically change convective planform and long-term lunar mantle evolution. Our model results suggest a relatively stable partially molten IBC layer that has surrounded the lunar core to the present day.Plain Language SummaryThe Moon's mantle is locally ilmenite rich. Previous models exploring the convective evolution of the lunar mantle did not consider the effects of ilmenite viscosity. Recent rock deformation experiments demonstrate that Fe-Ti oxide (ilmenite) is a low viscosity phase compared to olivine and other silicate minerals. Our modeling shows that ilmenite changes the lunar mantle plume process. An ilmenite-rich layer around the lunar core would be highly stable throughout geologic time, consistent with a partially molten, low viscosity layer around the core inferred from seismic attenuation and tidal dissipation.

  2. The effect of laparoscopic surgery in stage II and III right-sided colon cancer: a retrospective study

    Directory of Open Access Journals (Sweden)

    Kye Bong-Hyeon

    2012-05-01

    Full Text Available Abstract Background This retrospective study compared the clinicopathological results among three groups divided by time sequence to evaluate the impact of introducing laparoscopic surgery on long-term oncological outcomes for right-sided colon cancer. Methods From April 1986 to December 2006, 200 patients who underwent elective surgery with stage II and III right-sided colon cancer were analyzed. The period for group I referred back to the time when laparoscopic approach had not yet been introduced. The period for group II was designated as the time when first laparoscopic approach for right colectomy was carried out until we overcame its learning curve. The period for group III was the period after overcoming this learning curve. Results When groups I and II, and groups II and III were compared, overall survival (OS did not differ significantly whereas disease-free survival (DFS in groups I and III were statistically higher than in group II (P = 0.042 and P = 0.050. In group III, laparoscopic surgery had a tendency to provide better long-term OS ( P = 0.2036 and DFS ( P = 0.2356 than open surgery. Also, the incidence of local recurrence in group III (2.6% was significantly lower than that in groups II (7.4% and I (12.1% ( P = 0.013. Conclusions Institutions should standardize their techniques and then provide fellowship training for newcomers of laparoscopic colon cancer surgery. This technique once mastered will become the gold standard approach to colon surgery as it is both safe and feasible considering the oncological and technical aspects.

  3. Justification of a dose of diuretics in antihypertensive treatment of patients with essential hypertension stage II-III

    OpenAIRE

    Plesh, I. A.; Boreyko, L. D.; Slyvka, N. O.; Kshanovska, G. I.

    2017-01-01

    "Pressor natriuresis" coefficient in  ratio of daily urinary sodium excretion (ENadob) by means of  electrometric method using ionselective electrodes (SINO - 005) to average of median arterial pressure (MAPdob) a day  and character of circadian rhytm, by the method of daily monitoring of blood pressure (hardware «Solvaig») to optimize the dose of a diuretic in combined antihypertensive treatment was determened іn 65 patients with essential  hypertension (EH II-III stage and 26 control (normo...

  4. Transoral Robotic Surgery in Treating Patients With Benign or Stage I-IV Head and Neck Cancer

    Science.gov (United States)

    2014-11-07

    Recurrent Adenoid Cystic Carcinoma of the Oral Cavity; Recurrent Lymphoepithelioma of the Nasopharynx; Recurrent Lymphoepithelioma of the Oropharynx; Recurrent Mucoepidermoid Carcinoma of the Oral Cavity; Recurrent Squamous Cell Carcinoma of the Hypopharynx; Recurrent Squamous Cell Carcinoma of the Larynx; Recurrent Squamous Cell Carcinoma of the Lip and Oral Cavity; Recurrent Squamous Cell Carcinoma of the Nasopharynx; Recurrent Squamous Cell Carcinoma of the Oropharynx; Recurrent Verrucous Carcinoma of the Larynx; Recurrent Verrucous Carcinoma of the Oral Cavity; Stage I Adenoid Cystic Carcinoma of the Oral Cavity; Stage I Lymphoepithelioma of the Nasopharynx; Stage I Lymphoepithelioma of the Oropharynx; Stage I Mucoepidermoid Carcinoma of the Oral Cavity; Stage I Squamous Cell Carcinoma of the Hypopharynx; Stage I Squamous Cell Carcinoma of the Larynx; Stage I Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage I Squamous Cell Carcinoma of the Nasopharynx; Stage I Squamous Cell Carcinoma of the Oropharynx; Stage I Verrucous Carcinoma of the Larynx; Stage I Verrucous Carcinoma of the Oral Cavity; Stage II Adenoid Cystic Carcinoma of the Oral Cavity; Stage II Lymphoepithelioma of the Nasopharynx; Stage II Lymphoepithelioma of the Oropharynx; Stage II Mucoepidermoid Carcinoma of the Oral Cavity; Stage II Squamous Cell Carcinoma of the Hypopharynx; Stage II Squamous Cell Carcinoma of the Larynx; Stage II Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage II Squamous Cell Carcinoma of the Nasopharynx; Stage II Squamous Cell Carcinoma of the Oropharynx; Stage II Verrucous Carcinoma of the Larynx; Stage II Verrucous Carcinoma of the Oral Cavity; Stage III Adenoid Cystic Carcinoma of the Oral Cavity; Stage III Lymphoepithelioma of the Nasopharynx; Stage III Lymphoepithelioma of the Oropharynx; Stage III Mucoepidermoid Carcinoma of the Oral Cavity; Stage III Squamous Cell Carcinoma of the Hypopharynx; Stage III Squamous Cell Carcinoma of the Larynx; Stage

  5. The temperature of primary melts and mantle sources of komatiites, OIBs, MORBs and LIPs

    Science.gov (United States)

    Sobolev, Alexander

    2015-04-01

    There is general agreement that the convecting mantle, although mostly peridotitic in composition, is compositionally and thermally heterogeneous on different spatial scales. The amount, sizes, temperatures and compositions of these heterogeneities significantly affect mantle dynamics because they may diverge greatly from dominant peridotites in their density and fusibility. Differences in potential temperature and composition of mantle domains affect magma production and cannot be easily distinguished from each other. This has led to radically different interpretations of the melting anomalies that produce ocean-island basalts, large igneous provinces and komatiites: most scientists believe that they originate as hot, deep-sourced mantle plumes; but a small though influential group (e.g. Anderson 2005, Foulger, 2010) propose that they derive from high proportions of easily fusible recycled or delaminated crust, or in the case of komatiites contain large amount of H2O (e.g. Grove & Parman, 2004). The way to resolve this ambiguity is an independent estimation of temperature and composition of mantle sources of various types of magma. In this paper I report application of newly developed olivine-spinel-melt geothermometers based on partition of Al, Cr, Sc and Y for different primitive lavas from mid-ocean ridges, ocean-island basalts, large igneous provinces and komatiites. The results suggest significant variations of crystallization temperature for the same Fo of high magnesium olivines of different types of mantle-derived magmas: from the lowest (down to 1220 degree C) for MORB to the highest (up to over 1500 degree C) for komatiites and Siberian meimechites. These results match predictions from Fe-Mg olivine-melt equilibrium and confirm the relatively low temperature of the mantle source of MORB and higher temperatures in the mantle plumes that produce the OIB of Iceland, Hawaii, Gorgona, Archean komatiites and several LIPs (e.g Siberian and NAMP). The

  6. Sintering mantle mineral aggregates with submicron grains: examples of olivine and clinopyroxene

    Science.gov (United States)

    Tsubokawa, Y.; Ishikawa, M.

    2017-12-01

    Physical property of the major mantle minerals play an important role in the dynamic behavior of the Earth's mantle. Recently, it has been found that nano- to sub-micron scale frictional processes might control faulting processes and earthquake instability, and ultrafine-grained mineral aggregates thus have attracted the growing interest. Here we investigated a method for preparing polycrystalline clinoyproxene and polycrystalline olivine with grain size of sub-micron scale from natural crystals, two main constituents of the upper mantle. Nano-sized powders of both minerals are sintered under argon flow at temperatures ranging from 1130-1350 °C for 0.5-20 h. After sintering at 1180 °C and 1300 °C, we successfully fabricated polycrystalline clinopyroxene and polycrystalline olivine with grain size of physical properties of Earth's mantle.

  7. Analysis of PKP scattering using mantle mixing simulations and axisymmetric 3D waveforms

    Science.gov (United States)

    Haugland, Samuel M.; Ritsema, Jeroen; van Keken, Peter E.; Nissen-Meyer, Tarje

    2018-03-01

    The scattering of PKP waves in the lower mantle produces isolated signals before the PKIKP phase. We explore whether these so-called PKIKP precursors can be related to wave scattering off mid ocean ridge basalt (MORB) fragments that have been advected in the deep mantle throughout geologic time. We construct seismic models of small-scale (>20 km) heterogeneity in the lower mantle informed by mantle mixing simulations from Brandenburg et al. (2008) and generate PKIKP precursors using 3D, axisymmetric waveform simulations up to 0.75 Hz. We consider two end-member geodynamic models with fundamentally different distributions of MORB in the lower mantle. Our results suggest that the accumulation of MORB at the base of the mantle is a viable hypothesis for the origin of PKP scattering. We find that the strength of the PKIKP precursor amplitudes is consistent with P wave speed heterogeneity of 0.1-0.2%, as reported previously. The radial distribution of MORB has a profound effect on the strength of PKIKP precursors. Simulation of PKIKP precursors for models with an increasing MORB concentration in the lowermost 500 km of the mantle appears to reproduce most accurately the strength of PKIKP precursors in Global Seismic Network waveforms. These models assume that MORB has an excess density of at least 7%. Additional simulations of more complex geodynamic models will better constrain the geodynamic conditions to explain the significant variability of PKP scattering strength.

  8. Broad plumes rooted at the base of the Earth's mantle beneath major hotspots.

    Science.gov (United States)

    French, Scott W; Romanowicz, Barbara

    2015-09-03

    Plumes of hot upwelling rock rooted in the deep mantle have been proposed as a possible origin of hotspot volcanoes, but this idea is the subject of vigorous debate. On the basis of geodynamic computations, plumes of purely thermal origin should comprise thin tails, only several hundred kilometres wide, and be difficult to detect using standard seismic tomography techniques. Here we describe the use of a whole-mantle seismic imaging technique--combining accurate wavefield computations with information contained in whole seismic waveforms--that reveals the presence of broad (not thin), quasi-vertical conduits beneath many prominent hotspots. These conduits extend from the core-mantle boundary to about 1,000 kilometres below Earth's surface, where some are deflected horizontally, as though entrained into more vigorous upper-mantle circulation. At the base of the mantle, these conduits are rooted in patches of greatly reduced shear velocity that, in the case of Hawaii, Iceland and Samoa, correspond to the locations of known large ultralow-velocity zones. This correspondence clearly establishes a continuous connection between such zones and mantle plumes. We also show that the imaged conduits are robustly broader than classical thermal plume tails, suggesting that they are long-lived, and may have a thermochemical origin. Their vertical orientation suggests very sluggish background circulation below depths of 1,000 kilometres. Our results should provide constraints on studies of viscosity layering of Earth's mantle and guide further research into thermochemical convection.

  9. Mantle to surface degassing of carbon- and sulphur-rich alkaline magma at El Hierro, Canary Islands

    Science.gov (United States)

    Longpré, Marc-Antoine; Stix, John; Klügel, Andreas; Shimizu, Nobumichi

    2017-02-01

    Basaltic volcanoes transfer volatiles from the mantle to the surface of the Earth. The quantification of deep volatile fluxes relies heavily on estimates of the volatile content of primitive magmas, the best archive of which is provided by melt inclusions. Available data from volcanoes producing mafic alkaline lavas in a range of tectonic settings suggest high volatile fluxes, but information remains sparse, particularly for intraplate ocean islands. Here we present measurements of volatile and trace element concentrations, as well as sulphur speciation, in olivine-hosted melt inclusions and matrix glasses from quenched basanite lava balloon samples from the 2011-2012 submarine eruption at El Hierro, Canary Islands. The results reveal remarkably high concentrations of dissolved volatiles and incompatible trace elements in this magma, with ∼80 ppm Nb and up to 3420 ppm CO2, 3.0 wt.% H2O and 5080 ppm S. Reconstructed primitive CO2 contents, considering CO2/Nb systematics and possible CO2 sequestration in shrinkage bubbles, reach weight percent levels, indicating that carbon is a major constituent of Canary Island magmas at depth and that exsolution of a CO2-rich fluid begins in the mantle at pressures in excess of 1 GPa. Correlations between sulphur concentration, sulphur speciation and water content suggest strong reduction of an initially oxidised mantle magma, likely controlled by coupled H2O and S degassing. This late-stage redox change may have triggered sulphide saturation, recorded by globular sulphide inclusions in clinopyroxene and ulvöspinel. The El Hierro basanite thus had a particularly high volatile-carrying capacity and released a minimum of 1.3-2.1 Tg CO2 and 1.8-2.9 Tg S to the environment, causing substantial stress on the local submarine ecosystem. These results highlight the important contribution of alkaline ocean island volcanoes, such as the Canary Islands, to volatile fluxes from the mantle.

  10. Application of supercomputers to 3-D mantle convection

    International Nuclear Information System (INIS)

    Baumgardner, J.R.

    1986-01-01

    Current generation vector machines are providing for the first time the computing power needed to treat planetary mantle convection in a fully three-dimensional fashion. A numerical technique known as multigrid has been implemented in spherical geometry using a hierarchy of meshes constructed from the regular icosahedron to yield a highly efficient three-dimensional compressible Eulerian finite element hydrodynamics formulation. The paper describes the numerical method and presents convection solutions for the mantles of both the earth and the Moon. In the case of the Earth, the convection pattern is characterized by upwelling in narrow circular plumes originating at the core-mantle boundary and by downwelling in sheets or slabs derived from the cold upper boundary layer. The preferred number of plumes appears to be on the order of six or seven. For the Moon, the numerical results indicate that development of a predominately L = 2 pattern in later lunar history is a plausible explanation for the present large second-degree non-hydrostatic component in the lunar figure

  11. A Geochemical View on the Interplay Between Earth's Mantle and Crust

    Science.gov (United States)

    Chauvel, C.

    2017-12-01

    Over most of Earth history, oceanic and continental crust was created and destroyed. The formation of both types of crust involves the crystallization and differentiation of magmas producing by mantle melting. Their destruction proceeds by mechanical erosion and weathering above sea level, chemical alteration on the seafloor, and bulk recycling in subduction zones. All these processes enrich of some chemical element and deplete others but each process has its own effect on chemical elements. While the flux of material from mantle to crust is well understood, the return flux is much more complex. In contrast to mantle processes, erosion, weathering, chemical alteration and sedimentary processes strongly decouple elements such as the rare earths and high-field strength elements due to their different solubilities in surface fluids and mineralogical sorting during transport. Soluble elements such as strontium or uranium are quantitatively transported to the ocean by rivers and decoupled from less soluble elements. Over geological time, such decoupling significantly influences the extent to which chemical elements remain at the Earth's surface or find their way back to the mantle through subduction zones. For example, elements like Hf or Nd are retained in heavy minerals on continents whereas U and Sr are transported to the oceans and then in subduction zones to the mantle. The consequence is that different radiogenic isotopic systems give disparate age estimates for the continental crust; e.g, Hf ages could be too old. In subduction zones, chemical elements are also decoupled, due to contrasting behavior during dehydration or melting in subducting slabs. The material sent back into the mantle is generally enriched in non-soluble elements while most fluid-mobile elements return to the crust. This, in turn, affects the relationship between the Rb-Sr, Sm-Nd, Lu-Hf and U-Th-Pb isotopic systems and creates correlations unlike those based on magmatic processes. By

  12. Mission Moho: Rationale for drilling deep through the ocean crust into the upper mantle

    Science.gov (United States)

    Ildefonse, B.; Abe, N.; Kelemen, P. B.; Kumagai, H.; Teagle, D. A. H.; Wilson, D. S.; Moho Proponents, Mission

    2009-04-01

    Sampling a complete section of the ocean crust to the Moho was the original inspiration for scientific ocean drilling, and remains the main goal of the 21st Century Mohole Initiative in the IODP Science Plan. Fundamental questions about the composition, structure, and geophysical characteristics of the ocean lithosphere, and about the magnitude of chemical exchanges between the mantle, crust and oceans remain unresolved due to the absence of in-situ samples and measurements. The geological nature of the Mohorovičić discontinuity itself remains poorly constrained. "Mission Moho" is a proposal that was submitted to IODP in April 2007, with the ambition to drill completely through intact oceanic crust formed at a fast spreading rate, across the Moho and into the uppermost mantle. Although, eventually, no long-term mission was approved by IODP, the scientific objectives related to deep drilling in the ocean crust remain essential to our understanding of the Earth. These objectives are to : - Determine the geological meaning of the Moho in different oceanic settings, determine the in situ composition, structure and physical properties of the uppermost mantle, and understand mantle melt migration, - Determine the bulk composition of the oceanic crust to establish the chemical links between erupted lavas and primary mantle melts, understand the extent and intensity of seawater hydrothermal exchange with the lithosphere, and estimate the chemical fluxes returned to the mantle by subduction, - Test competing hypotheses of the ocean crust accretion at fast spreading mid-ocean ridges, and quantify the linkages and feedbacks between magma intrusion, hydrothermal circulation and tectonic activity, - Calibrate regional seismic measurements against recovered cores and borehole measurements, and understand the origin of marine magnetic anomalies, - Establish the limits of life in the ocean lithosphere. The "MoHole" was planned as the final stage of Mission Moho, which requires

  13. Pb isotope constaints on the extent of crustal recycling into a steady state mantle

    International Nuclear Information System (INIS)

    Galer, S.J.G.; Goldstein, S.L.; Onions, R.K.

    1988-01-01

    Isotopic and geochemical evidence was discussed against recycling of continental crust into the mantle. Element ratios such as Sm/Nd, Th/Sc, and U/Pb in sedimentary masses have remained relatively constant throughout Earth history, and this can only be reconciled with steady state recycling models if new crustal materials added from the mantle have had similar ratios. Such recycling models would also require shorter processing times for U, Th, and Pb through the mantle than are geodynamically reasonable. Models favoring subduction of pelagic sediments as the only recycling mechanism fail to account for the Pb isotopic signature of the mantle. Recycling of bulk crust with Pb isotopic compositions similar to those expected for primitive mantle would be permissable with available data, but there appear to be no plausible tectonic mechanisms to carry this out

  14. The Universal Cpx Jd-Di barometer for mantle peridotite eclogite and pyroxenites and it using for the mantle petrology

    Science.gov (United States)

    Ashchepkov, Igor

    2015-04-01

    The Jd-Di exchange in clinopyroxenes used for the calibration of pyroxene barometer (Ashchepkov, 2000;2002; Ashchepkov et al 2010;2011;2012) was transformed to make one universal equation for mantle peridotite eclogites and pyroxenites. The original barometer (Ashchepkov, 2002) calibrated on pressures produced by Opx barometry (McGregor , 1974) was transformed (Ashchepkov et al ., 2004; 2010; 2011) to satisfy the increasing data bases for the mantle xenoliths and experimental values 530 in peridotitic and 650 in elcogitic systems . The obtained difference Pd =Pcpx- Pexp were studied for the dependence on each component and their combination . Instead of the common activities we used the temperature-dependent empirical equations. The three separate equations for the common peridotites, pyroxenites and eclogites (Ashchepkov et al., 2010) were checked and complex To and Al-Na-Fe dependent universal coefficients were received. The KD is determined as follows: KD=Na/AlCr*Mg/Ca The logarithmic dependence between P and KD was transformed to a linear one. Final pressure equations are: AlCr=(Al-0.01) *((T-600)/700)**0.75+Cr*(ToK-100)/1000+(4*Ti-0.0125)/ (T0-801)*650 +0.55*((Fe-0.23) *(T0-900)/10000-K) P=0.26*(5+12*(Al+0.30*Na)KD* ToK**0.75 /(1+Fe+ Fe*(ToK-600)/1000)-ln(1273/ ToK))*40*(7*Na-Al-15*Ti+10*Cr+Mg/4)+7.5*Si-20*( Al*Na*Mg/Ca/(Al-2*Ti+Na-2*Fe/(Fe+Mg))+50*(Na+0.1*Al-2*Ti+0.05*Mg-0.22*Ca-0.7*Na)/Ca). Obtained equation in combination with the (Nimis,Taylor, 2000) thermometer allow to reconstruct position of the magma feeder systems of the alkali basaltic magma withing the mantle diapirs in modern platforms like in Vitim plateau (Ashchepkov et al., 2011) and now was applicated to reconstruct the deep seated magma conduits beneath the mountain collision systems, island arcs ocean plateaus etc. This equation allows to receive the positions of the major groups of eclogites mantle sections and to find out the regularities of their behavior. The Fe rich eclogites commonly

  15. Evolution of depleted mantle: The lead perspective

    Science.gov (United States)

    Tilton, George R.

    1983-07-01

    Isotopic data have established that, compared to estimated bulk earth abundances, the sources of oceanic basaltic lavas have been depleted in large ion lithophile elements for at least several billions of years. Various data on the Tertiary-Mesozoic Gorgona komatiite and Cretaceous Oka carbonatite show that those rocks also sample depleted mantle sources. This information is used by analogy to compare Pb isotopic data from 2.6 billion year old komatiite and carbonatite from the Suomussalmi belt of eastern Finland and Munro Township, Ontario that are with associated granitic rocks and ores that should contain marked crustal components. Within experimental error no differences are detected in the isotopic composition of initial Pb in either of the rock suites. These observations agree closely with Sr and Nd data from other laboratories showing that depleted mantle could not have originated in those areas more than a few tenths of billions of years before the rocks were emplaced. On a world-wide basis the Pb isotope data are consistent with production of depleted mantle by continuous differentiation processes acting over approximately the past 3 billion years. The data show that Pb evolution is more complex than the simpler models derived from the Rb-Sr and Sm-Nd systems. The nature of the complexity is still poorly understood.

  16. Linking Serpentinite Geochemistry with Possible Alteration and Evolution of Supra-Subduction Wedge Mantle

    Science.gov (United States)

    Scambelluri, M.; Cannaò, E.; Agostini, S.; Gilio, M.

    2016-12-01

    Serpentinites are able to transport and release volatiles and fluid-mobile elements (FME) found in arc magmas. Constraining the trace element compositions of these rocks and of fluids released by de-serpentinization improves our knowledge of mass transfer from subduction zones to volcanic arcs, and of the role of slab and wedge mantle in this global process. Studies of high-pressure ultramafic rocks exhumed from plate interface settings reveal the fluid/rock interactions atop the slab and the processes that can affect the mantle wedge. Alpine eclogite-facies antigorite serpentinite (Voltri Massif) and fully de-serpentinized meta-peridotite (Cima di Gagnone) are enriched in sediment-derived As, Sb, U, Pb before peak dehydration. Their Sr, Pb and B isotopic compositions are reset during prograde (forearc) interaction with slab fluids. The eclogitic garnet and olivine from the Cima di Gagnone metaperidotite trap primary inclusions of the fluid released during breakdown of antigorite and chlorite. The inclusions display FME enrichments (high Cl, S; variable Cs, Rb, Ba, B, Pb, As, Sb) indicating element release from rocks to fluids during dehydration under subarc conditions. Our studies show that serpentinized mantle rocks from subduction zones sequester FME from slab fluids and convey these components and radiogenic isotopes into the mantle wedge upon dehydration. The geochemical processes revealed by such plate-interface rocks can apply to the supra-subduction mantle. Shallow element release from slabs to mantle wedge, downdrag of this altered mantle and its subsequent (subarc) dehydration transfers crust-derived FMEs to the arc magma sources without the need of concomitant subarc dehydration/melting of metasedimentary slab components. The slab signature detected in arc lavas can thus result from geochemical mixing of sediment, oceanic crust and ultramafic reservoirs into altered wedge-mantle rocks, rather than being attributed to multiple fluids.

  17. The African upper mantle and its relationship to tectonics and surface geology

    Science.gov (United States)

    Priestley, Keith; McKenzie, Dan; Debayle, Eric; Pilidou, Sylvana

    2008-12-01

    This paper focuses on the upper-mantle velocity structure of the African continent and its relationship to the surface geology. The distribution of seismographs and earthquakes providing seismograms for this study results in good fundamental and higher mode path coverage by a large number of relatively short propagation paths, allowing us to image the SV-wave speed structure, with a horizontal resolution of several hundred kilometres and a vertical resolution of ~50 km, to a depth of about 400 km. The difference in mantle structure between the Archean and Pan-African terranes is apparent in our African upper-mantle shear wave model. High-velocity (4-7 per cent) roots exist beneath the cratons. Below the West African, Congo and Tanzanian Cratons, these extend to 225-250 km depth, but beneath the Kalahari Craton, the high wave speed root extends to only ~170 km. With the exception of the Damara Belt that separates the Congo and Kalahari Cratons, any high-speed upper-mantle lid below the Pan-African terranes is too thin to be resolved by our long-period surface wave technique. The Damara Belt is underlain by higher wave speeds, similar to those observed beneath the Kalahari Craton. Extremely low SV-wave speeds occur to the bottom of our model beneath the Afar region. The temperature of the African upper mantle is determined from the SV-wave speed model. Large temperature variations occur at 125 km depth with low temperatures beneath west Africa and all of southern Africa and warm mantle beneath the Pan-African terrane of northern Africa. At 175 km depth, cool upper mantle occurs below the West African, Congo, Tanzanian and Kalahari Cratons and anomalously warm mantle occurs below a zone in northcentral Africa and beneath the region surrounding the Red Sea. All of the African volcanic centres are located above regions of warm upper mantle. The temperature profiles were fit to a geotherm to determine the thickness of the African lithosphere. Thick lithosphere exists

  18. Evolution of the Oxidation State of the Earth's Mantle

    Science.gov (United States)

    Danielson, L. R.; Righter, K.; Keller, L.; Christoffersen, E.; Rahman, Z.

    2015-01-01

    The oxidation state of the Earth's mantle during formation remains an unresolved question, whether it was constant throughout planetary accretion, transitioned from reduced to oxidized, or from oxidized to reduced. We investigate the stability of Fe3(+) at depth, in order to constrain processes (water, late accretion, dissociation of FeO) which may reduce or oxidize the Earth's mantle. In our previous experiments on shergottite compositions, variable fO2, T, and P less than 4 GPa, Fe3(+)/sigma Fe decreased slightly with increasing P, similar to terrestrial basalt. For oxidizing experiments less than 7GPa, Fe3(+)/sigma Fe decreased as well, but it's unclear from previous modelling whether the deeper mantle could retain significant Fe3(+). Our current experiments expand our pressure range deeper into the Earth's mantle and focus on compositions and conditions relevant to the early Earth. Preliminary multi-anvil experiments with Knippa basalt as the starting composition were conducted at 5-7 GPa and 1800 C, using a molybdenum capsule to set the fO2 near IW, by buffering with Mo-MoO3. TEM and EELS analyses revealed the run products quenched to polycrystalline phases, with the major phase pyroxene containing approximately equal to Fe3(+)/2(+). Experiments are underway to produce glassy samples that can be measured by EELS and XANES, and are conducted at higher pressures.

  19. A possible mechanism for earthquakes found in the mantle wedge of the Nazca subduction zone

    Science.gov (United States)

    Warren, L. M.; Chang, Y.; Prieto, G. A.

    2017-12-01

    Beneath Colombia, the Cauca cluster of intermediate-depth earthquakes extends for 200 km along the trench (3.5°N-5.5°N, 77.0°W-75.3°W) and, with 58 earthquakes per year with local magnitude ML >= 2.5, has a higher rate of seismicity than the subduction zone immediately to the north or south. By precisely locating 433 cluster earthquakes from 1/2010-3/2014 with data from the Colombian National Seismic Network, we found that the earthquakes are located both in a continuous Nazca plate subducting at an angle of 33°-43° and in the overlying mantle wedge. The mantle wedge earthquakes (12% of the earthquakes) form two isolated 40-km-tall columns extending perpendicular to the subducting slab. Using waveform inversion, we computed focal mechanisms for 69 of the larger earthquakes. The focal mechanisms are variable, but the intraslab earthquakes are generally consistent with an in-slab extensional stress axis oriented 25° counterclockwise from the down-dip direction. We suggest that the observed mantle wedge earthquakes are the result of hydrofracture in a relatively cool mantle wedge. This segment of the Nazca Plate is currently subducting at a normal angle, but Wagner et al. (2017) suggested that a flat slab slowly developed in the region between 9-5.9 Ma and persisted until 4 Ma. During flat slab subduction, the overlying mantle wedge typically cools because it is cut off from mantle corner flow. After hydrous minerals in the slab dehydrate, the dehydrated fluid is expelled from the slab and migrates through the mantle wedge. If a cool mantle wedge remains today, fluid dehydrated from the slab may generate earthquakes by hydrofracture, with the mantle wedge earthquakes representing fluid migration pathways. Dahm's (2000) model of water-filled fracture propagation in the mantle wedge shows hydrofractures propagating normal to the subducting slab and extending tens of km into the mantle wedge, as we observe.

  20. Crystal preferred orientations of minerals from mantle xenoliths in alkali basaltic rocks form the Catalan Volcanic Zone (NE Spain)

    Science.gov (United States)

    Fernández-Roig, Mercè; Galán, Gumer; Mariani, Elisabetta

    2015-04-01

    Mantle xenoliths in alkali basaltic rocks from the Catalan Volcanic Zone, associated with the Neogene-Quaternary rift system in NE Spain, are formed of anhydrous spinel lherzolites and harzburgites with minor olivine websterites. Both peridotites are considered residues of variable degrees of partial melting, later affected by metasomatism, especially the harzburgites. These and the websterites display protogranular microstructures, whereas lherzolites show continuous variation between protogranular, porphyroclastic and equigranular forms. Thermometric data of new xenoliths indicate that protogranular harzburgites, lherzolites and websterites were equilibrated at higher temperatures than porphyroclastic and equigranular lherzolites. Mineral chemistry also indicates lower equilibrium pressure for porphyroclastic and equigranular lherzolites than for the protogranular ones. Crystal preferred orientations (CPOs) of olivine and pyroxenes from these new xenoliths were determined with the EBSD-SEM technique to identify the deformation stages affecting the lithospheric mantle in this zone and to assess the relationships between the deformation fabrics, processes and microstructures. Olivine CPOs in protogranular harzburgites, lherzolites and a pyroxenite display [010]-fiber patterns characterized by a strong point concentration of the [010] axis normal to the foliation and girdle distribution of [100] and [001] axes within the foliation plane. Olivine CPO symmetry in porphyroclastic and equigranular lherzolites varies continuously from [010]-fiber to orthorhombic and [100]-fiber types. The orthorhombic patterns are characterized by scattered maxima of the three axes, which are normal between them. The rare [100]-fiber patterns display strong point concentration of [100] axis, with normal girdle distribution of the other two axes, which are aligned with each other. The patterns of pyroxene CPOs are more dispersed than those of olivine, especially for clinopyroxene, but

  1. Enhancement MRI evaluation of neuroblastoma staging in children

    International Nuclear Information System (INIS)

    Li Xin; Wang Chunxiang; Zhao Bin; Liu Peifang

    2002-01-01

    Objective: To evaluate the value and limitation of Gd-DTPA enhanced MRI for neuroblastoma staging in children. Methods: Twelve cases of neuroblastoma proved by operation or bone marrow aspiration were examined by gadolinium-enhanced MRI. The age ranged from seven months to five years, mean 3.7 years. Eight tumors originated from adrenal, and four from posterior mediastinum. Conventional sequences, double dose gadolinium-enhanced MRI, and 3D CEMRA were used in all patients. Six cases were examined by CT in same time. Imaging staging on surgic-histopathological-based International Neuroblastoma Staging System (INSS) was performed. Results: Six patients were staged by CT, including stage I-II in 2 cases, stage III in 4 cases, and stage IV in none. Twelve patients were staged by conventional MRI, including stage I-II in 2 cases, stage III in 9 cases, and stage IV in 1 case. Twelve patients were staged by double dose gadolinium-enhanced MRI, including stage I-II in 1 case, stage III in 1 case, and stage IV in 10 cases. Conclusion: Gadolinium-enhanced MRI was a single best imaging modality for neuroblastoma, most useful for distal to diaphragm metastasis, dumbbell tumor intraspinal extension, and bone marrow metastasis that was not detected by aspirate examination. Enhancement MRI was important in evaluating the therapy and was also helpful in assessing the therapeutic efficacy and relapse. 3D CEMRA helps demonstrate large vascular encasement and tumor erosion into important organs, and it is useful in assessing the respectability. Long examination time and lack in showing the characteristic calcium were the limitations

  2. Study on removal technology for thorium in the waste gas-lamp mantle

    International Nuclear Information System (INIS)

    Shi Yucheng; Wang Chengbao; Zhang Ping; Xu Lingqi; Jiang Shangen

    1999-01-01

    The author describes thorium removal technology and its application in the handling of the waste gas-lamp mantle that produced during the production of gas-lamp process. After laboratory test, pilot test, trial run and engineering scale use, the thorium removal technology is mainly as follows: soak the waste gas-lamp mantle into the ceramic vat with the nitric acid solution twice and wash it with the tap water twice. The volume of the ceramic vat is 500 L and the concentration of the nitric acid solution is 2 mol/L. After handling, the thorium removal rate can reach 99.97% and the residual thorium will be less than 160 Bq/kg. The waste gas-lamp mantle can be buried under the ground or be handled in the other ways just as the harmless waste. The nitric acid solution, in which gas-lamp mantle has been soaked, should be extracted with TBP, then back extracted with diluted hydrochloric acid. After supplementing the thorium nitrate into the back extracted liquid, the liquid can be reused in the gas-lamp mantle production. The waste water from the handling process can be handled together with waste water from production process

  3. Deformation, Fluid Flow and Mantle Serpentinization at Oceanic Transform Faults

    Science.gov (United States)

    Rupke, L.; Hasenclever, J.

    2017-12-01

    Oceanic transform faults (OTF) and fracture zones have long been hypothesized to be sites of enhanced fluid flow and biogeochemical exchange. In this context, the serpentine forming interaction between seawater and cold lithospheric mantle rocks is particularly interesting. The transformation of peridotite to serpentinite not only leads to hydration of oceanic plates and is thereby an important agent of the geological water cycle, it is also a mechanism of abiotic hydrogen and methane formation, which can support archeal and bacterial communities at the seafloor. Inferring the likely amount of mantle undergoing serpentinization reactions therefore allows estimating the amount of biomass that may be autotrophically produced at and around oceanic transform faults and mid-ocean ridges Here we present results of 3-D geodynamic model simulations that explore the interrelations between deformation, fluid flow, and mantle serpentinization at oceanic transform faults. We investigate how slip rate and fault offset affect the predicted patterns of mantle serpentinization around oceanic transform faults. Global rates of mantle serpentinization and associated H2 production are calculated by integrating the modeling results with plate boundary data. The global additional OTF-related production of H2 is found to be between 6.1 and 10.7 x 1011 mol per year, which is comparable to the predicted background mid-ocean ridge rate of 4.1 - 15.0 x 1011 mol H2/yr. This points to oceanic transform faults as potential sites of intense fluid-rock interaction, where chemosynthetic life could be sustained by serpentinization reactions.

  4. Nd, Sr and Pb isotopic systematics in a three-component mantle: a new perspective

    International Nuclear Information System (INIS)

    Zindler, A.; Goldstein, S.

    1982-01-01

    Average Nd, Sr and Pb isotopic compositions for oceanic basalts indicate that the present day mantle consists of three chemically independent components. The recognition of a third mantle component obviates geochemical arguments which have been used to support chemical stratification and convective decoupling within the mantle, and the transport of lead to the core throughout geological time. (author)

  5. Thermal Structure and Mantle Dynamics of Rocky Exoplanets

    Science.gov (United States)

    Wagner, F. W.; Tosi, N.; Hussmann, H.; Sohl, F.

    2011-12-01

    The confirmed detections of CoRoT-7b and Kepler-10b reveal that rocky exoplanets exist. Moreover, recent theoretical studies suggest that small planets beyond the Solar System are indeed common and many of them will be discovered by increasingly precise observational surveys in the years ahead. The knowledge about the interior structure and thermal state of exoplanet interiors provides crucial theoretical input not only for classification and characterization of individual planetary bodies, but also to better understand the origin and evolution of the Solar System and the Earth in general. These developments and considerations have motivated us to address several questions concerning thermal structure and interior dynamics of terrestrial exoplanets. In the present study, depth-dependent structural models of solid exoplanet interiors have been constructed in conjunction with a mixing length approach to calculate self-consistently the radial distribution of temperature and heat flux. Furthermore, 2-D convection simulations using the compressible anelastic approximation have been carried through to examine the effect of thermodynamic quantities (e.g., thermal expansivity) on mantle convection pattern within rocky planets more massive than the Earth. In comparison to parameterized convection models, our calculated results predict generally hotter planetary interiors, which are mainly attributed to a viscosity-regulating feedback mechanism involving temperature and pressure. We find that density and thermal conductivity increase with depth by a factor of two to three, however, thermal expansivity decreases by more than an order of magnitude across the mantle for planets as massive as CoRoT-7b or Kepler-10b. The specific heat capacity is observed to stay almost constant over an extended region of the lower mantle. The planform of mantle convection is strongly modified in the presence of depth-dependent thermodynamic quantities with hot upwellings (plumes) rising across

  6. The elastic constants of MgSiO3 perovskite at pressures and temperatures of the Earth's mantle.

    Science.gov (United States)

    Oganov, A R; Brodholt, J P; Price, G D

    2001-06-21

    The temperature anomalies in the Earth's mantle associated with thermal convection can be inferred from seismic tomography, provided that the elastic properties of mantle minerals are known as a function of temperature at mantle pressures. At present, however, such information is difficult to obtain directly through laboratory experiments. We have therefore taken advantage of recent advances in computer technology, and have performed finite-temperature ab initio molecular dynamics simulations of the elastic properties of MgSiO3 perovskite, the major mineral of the lower mantle, at relevant thermodynamic conditions. When combined with the results from tomographic images of the mantle, our results indicate that the lower mantle is either significantly anelastic or compositionally heterogeneous on large scales. We found the temperature contrast between the coldest and hottest regions of the mantle, at a given depth, to be about 800 K at 1,000 km, 1,500 K at 2,000 km, and possibly over 2,000 K at the core-mantle boundary.

  7. Stages of weathering mantle formation from carbonate rocks in the light of rare earth elements (REE) and Sr-Nd-Pb isotopes

    Science.gov (United States)

    Hissler, Christophe; Stille, Peter

    2015-04-01

    Weathering mantles are widespread and include lateritic, sandy and kaolinite-rich saprolites and residuals of partially dissolved rocks. These old regolith systems have a complex history of formation and may present a polycyclic evolution due to successive geological and pedogenetic processes that affected the profile. Until now, only few studies highlighted the unusual high content of associated trace elements in weathering mantles originating from carbonate rocks, which have been poorly studied, compared to those developing on magmatic bedrocks. For instance, these enrichments can be up to five times the content of the underlying carbonate rocks. However, these studies also showed that the carbonate bedrock content only partially explains the soil enrichment for all the considered major and trace elements. Up to now, neither soil, nor saprolite formation has to our knowledge been geochemically elucidated. Therefore, the aim of this study was to examine more closely the soil forming dynamics and the relationship of the chemical soil composition to potential sources. REE distribution patterns and Sr-Nd-Pb isotope ratios have been used because they are particularly well suited to identify trace element migration, to recognize origin and mixing processes and, in addition, to decipher possible anthropogenic and/or "natural" atmosphere-derived contributions to the soil. Moreover, leaching experiments have been applied to identify mobile phases in the soil system and to yield information on the stability of trace elements and especially on their behaviour in these Fe-enriched carbonate systems. All these geochemical informations indicate that the cambisol developing on such a typical weathering mantle ("terra fusca") has been formed through weathering of a condensed Bajocian limestone-marl facies. This facies shows compared to average world carbonates important trace element enrichments. Their trace element distribution patterns are similar to those of the soil

  8. High Resolution Global Electrical Conductivity Variations in the Earth's Mantle

    Science.gov (United States)

    Kelbert, A.; Sun, J.; Egbert, G. D.

    2013-12-01

    Electrical conductivity of the Earth's mantle is a valuable constraint on the water content and melting processes. In Kelbert et al. (2009), we obtained the first global inverse model of electrical conductivity in the mantle capable of providing constraints on the lateral variations in mantle water content. However, in doing so we had to compromise on the problem complexity by using the historically very primitive ionospheric and magnetospheric source assumptions. In particular, possible model contamination by the auroral current systems had greatly restricted our use of available data. We have now addressed this problem by inverting for the external sources along with the electrical conductivity variations. In this study, we still focus primarily on long period data that are dominated by quasi-zonal source fields. The improved understanding of the ionospheric sources allows us to invert the magnetic fields directly, without a correction for the source and/or the use of transfer functions. It allows us to extend the period range of available data to 1.2 days - 102 days, achieving better sensitivity to the upper mantle and transition zone structures. Finally, once the source effects in the data are accounted for, a much larger subset of observatories may be used in the electrical conductivity inversion. Here, we use full magnetic fields at 207 geomagnetic observatories, which include mid-latitude, equatorial and high latitude data. Observatory hourly means from the years 1958-2010 are employed. The improved quality and spatial distribution of the data set, as well as the high resolution modeling and inversion using degree and order 40 spherical harmonics mapped to a 2x2 degree lateral grid, all contribute to the much improved resolution of our models, representing a conceptual step forward in global electromagnetic sounding. We present a fully three-dimensional, global electrical conductivity model of the Earth's mantle as inferred from ground geomagnetic

  9. Origin and Distribution of Water Contents in Continental and Oceanic Lithospheric Mantle

    Science.gov (United States)

    Peslier, Anne H.

    2013-01-01

    The water content distribution of the upper mantle will be reviewed as based on the peridotite record. The amount of water in cratonic xenoliths appears controlled by metasomatism while that of the oceanic mantle retains in part the signature of melting events. In both cases, the water distribution is heterogeneous both with depth and laterally, depending on localized water re-enrichments next to melt/fluid channels. The consequence of the water distribution on the rheology of the upper mantle and the location of the lithosphere-asthenosphere boundary will also be discussed.

  10. Risk Factors for Complications Differ Between Stages of Tissue-Expander Breast Reconstruction.

    Science.gov (United States)

    Lovecchio, Francis; Jordan, Sumanas W; Lim, Seokchun; Fine, Neil A; Kim, John Y S

    2015-09-01

    Tissue-expander (TE) placement followed by implant exchange is currently the most popular method of breast reconstruction. There is a relative paucity of data demonstrating patient factors that predict complications specifically by stage of surgery. The present study attempts to determine what complications are most likely to occur at each stage and how the risk factors for complications vary by stage of reconstruction. A retrospective chart review was performed on all 1275 patients who had TEs placed by the 2 senior authors between 2004 and 2013. Complication rates were determined at each stage of reconstruction, and these rates were further compared between patients who had pre-stage I radiation, post-stage I radiation, and no radiation exposure. Multivariate logistic regression was used to identify independent predictors of complications at each stage of reconstruction. A total of 1639 consecutive TEs were placed by the senior authors during the study period. The overall rate for experiencing a complication at any stage of surgery was 17%. Complications occurred at uniformly higher rates during stage I for all complications (92% stage I vs 7% stage II vs 1% stage III, P higher intraoperative percent fill (OR, 3.3; 95% CI, 1.7-6.3). Post-stage I radiation was the only independent risk factor for a stage II complication (OR, 4.5; 95% CI, 1.4-15.2). Complications occur at higher rates after stage I than after stage II, and as expected, stage III complications are exceedingly rare. Risk factors for stage I complications are different from risk factors for stage II complications. Body mass index and smoking are associated with complications at stage I, but do not predict complications at stage II surgery. The stratification of risk factors by stage of surgery will help surgeons and patients better manage both risk and expectations.

  11. Harvesting policy for a delayed stage-structured Holling II predator-prey model with impulsive stocking prey

    International Nuclear Information System (INIS)

    Jiao Jianjun; Meng Xinzhu; Chen Lansun

    2009-01-01

    A predator-prey model with a stage structure for the predator, which improves the assumption that each individual predator has the same ability to capture prey, is proposed by Wang et al. [Wang W, Mulone G, Salemi F, Salone V. Permanence and stability of a stage-structured predator-prey model. J Math Anal Appl 2001;262:499-528]. It is assumed that immature individuals and mature individuals of the predator are divided by a fixed age and that immature predators do not have the ability to attack prey. We do economic management behavior for Wang model [Wang et al., 2001] by continuous harvesting on predator and impulsive stocking on prey. Then, a delayed stage-structured Holling type II predator-prey model with impulsive stocking prey and continuous harvesting predator is established. It is also assumed that the predating products of the predator is only to increase its bearing ability. We obtain the sufficient conditions of the global attractivity of predator-extinction boundary periodic solution and the permanence of the system. Our results show that the behavior of impulsive stocking prey plays an important role for the permanence of the system, and provide tactical basis for the biological resource management. Further, the numerical analysis is also inserted to illuminate the dynamics of the system.

  12. Nitrogen evolution within the Earth's atmosphere-mantle system assessed by recycling in subduction zones

    Science.gov (United States)

    Mallik, Ananya; Li, Yuan; Wiedenbeck, Michael

    2018-01-01

    Understanding the evolution of nitrogen (N) across Earth's history requires a comprehensive understanding of N's behaviour in the Earth's mantle - a massive reservoir of this volatile element. Investigation of terrestrial N systematics also requires assessment of its evolution in the Earth's atmosphere, especially to constrain the N content of the Archaean atmosphere, which potentially impacted water retention on the post-accretion Earth, potentially causing enough warming of surface temperatures for liquid water to exist. We estimated the proportion of recycled N in the Earth's mantle today, the isotopic composition of the primitive mantle, and the N content of the Archaean atmosphere based on the recycling rates of N in modern-day subduction zones. We have constrained recycling rates in modern-day subduction zones by focusing on the mechanism and efficiency of N transfer from the subducting slab to the sub-arc mantle by both aqueous fluids and slab partial melts. We also address the transfer of N by aqueous fluids as per the model of Li and Keppler (2014). For slab partial melts, we constrained the transfer of N in two ways - firstly, by an experimental study of the solubility limit of N in melt (which provides an upper estimate of N uptake by slab partial melts) and, secondly, by the partitioning of N between the slab and its partial melt. Globally, 45-74% of N introduced into the mantle by subduction enters the deep mantle past the arc magmatism filter, after taking into account the loss of N from the mantle by degassing at mid-ocean ridges, ocean islands and back-arcs. Although the majority of the N in the present-day mantle remains of primordial origin, our results point to a significant, albeit minor proportion of mantle N that is of recycled origin (17 ± 8% or 12 ± 5% of N in the present-day mantle has undergone recycling assuming that modern-style subduction was initiated 4 or 3 billion years ago, respectively). This proportion of recycled N is enough to

  13. Digging Deep: Is Lunar Mantle Excavated Around the Imbrium Basin?

    Science.gov (United States)

    Klima, R. L.; Bretzfelder, J.; Buczkowski, D.; Ernst, C. M.; Greenhagen, B. T.; Petro, N. E.; Shusterman, M. L.

    2017-12-01

    The Moon has experienced over a dozen impacts resulting in basins large enough to have excavated mantle material. With many of those basins concentrated on the lunar near side, and extensive regolith mixing since the lunar magma ocean crystallized, one might expect that some mantle material would have been found among the lunar samples on Earth. However, so far, no mantle clasts have been definitively identified in lunar samples [1]. From orbit, a number of olivine-bearing localities, potentially sourced from the mantle, have been identified around impact basins [2]. Based on analysis of near-infrared (NIR) and imaging data, [3] suggest that roughly 60% of these sites represent olivine from the mantle. If this is the case and the blocks are coherent and not extensively mixed into the regolith, these deposits should be ultramafic, containing olivine and/or pyroxenes and little to no plagioclase. In the mid-infrared, they would thus exhibit Christiansen features at wavelengths in excess of 8.5 μm, which has not been observed in global studies using the Diviner Lunar Radiometer [4]. We present an integrated study of the massifs surrounding the Imbrium basin, which, at over 1000 km wide, is large enough to have penetrated through the lunar crust and into the mantle. These massifs are clearly associated with the Imbrium basin-forming impact, but existing geological maps do not distinguish between whether they are likely ejecta or rather uplifted from beneath the surface during crustal rebound [5]. We examine these massifs using vis, NIR and Mid IR data to determine the relationships between and the bulk mineralogy of local lithologies. NIR data suggest that the massifs contain exposures of four dominant minerals: olivine, Mg-rich orthopyroxene, a second low-Ca pyroxene, and anorthite. Mid IR results suggest that though many of these massifs are plagioclase-rich, portions of some may be significantly more mafic. We will present our growing mineralogical map of the

  14. Demographics and Outcomes of Stage I-II Merkel Cell Carcinoma Treated with Mohs Micrographic Surgery Compared with Wide Local Excision in the National Cancer Data Base.

    Science.gov (United States)

    Singh, Babu; Qureshi, Muhammad M; Truong, Minh Tam; Sahni, Debjani

    2018-02-03

    The optimal surgical approach (wide local excision (WLE) vs. Mohs micrographic surgery (MOHS)) for treating Merkel cell carcinoma (MCC) is yet to be determined. To compare survival outcomes in patients with early stage MCC treated with MOHS versus WLE. A retrospective review of all cases in the National Cancer Data Base (NCDB) of MCC of clinical Stage I-II MCC treated with WLE or MOHS was performed. 1,795 cases of Stage I-II MCC were identified who underwent WLE (N=1,685) or MOHS (N=110). There was no difference in residual tumor on surgical margins between the two treatment groups (p=0.588). On multivariate analysis, there was no difference in overall survival between the treatment modalities (adjusted HR 1.02; 95% CI 0.72-1.45, p=0.897). There was no difference in overall survival between the two groups on propensity score matched analysis. Disease specific survival was not reported as this data in not available in the NCDB. MOHS appears to be as effective as WLE in treating early stage MCC. Copyright © 2018. Published by Elsevier Inc.

  15. Life Cycle of Mantle Plumes: A perspective from the Galapagos Plume (Invited)

    Science.gov (United States)

    Gazel, E.; Herzberg, C. T.

    2009-12-01

    Hotspots are localized sources of heat and magmatism considered as modern-day evidence of mantle plumes. Some hotspots are related to massive magmatic production that generated Large Igneous Provinces (LIPS), an initial-peak phase of plume activity with a mantle source hotter and more magmatically productive than present-day hotspots. Geological mapping and geochronological studies have shown much lower eruption rates for OIB compared to lavas from Large Igneous Provinces LIPS such as oceanic plateaus and continental flood provinces. Our study is the first quantitative petrological comparison of mantle source temperatures and extent of melting for OIB and LIP sources. The wide range of primary magma compositions and inferred mantle potential temperatures for each LIP and OIB occurrence suggest that this rocks originated form a hotspot, a spatially localized source of heat and magmatism restricted in time. Extensive outcrops of basalt, picrite, and sometimes komatiite with circa 65-95 Ma ages occupy portions of the pacific shore of Central and South America included in the Caribbean Large Igneous Province (CLIP). There is general consensus of a Pacific-origin of CLIP and most studies suggest that it was produced by melting in the Galapagos mantle plume. The Galapagos connection is consistent with isotopic and geochemical similarities with lavas from the present-day Galapagos hotspot. A Galapagos link for rocks in South American oceanic complexes (eg. the island of Gorgona) is more controversial and requires future work. The MgO and FeO contents of lavas from the Galapagos related lavas and their primary magmas have decreased since the Cretaceous. From petrological modeling we infer that these changes reflect a cooling of the Galapagos mantle plume from a potential temperature of 1560-1620 C in the Cretaceous to 1500 C at the present time. These temperatures are higher than 1350 C for ambient mantle associated with oceanic ridges, and provide support for the mantle

  16. Markov Chain Monte Carlo Inversion of Mantle Temperature and Composition, with Application to Iceland

    Science.gov (United States)

    Brown, Eric; Petersen, Kenni; Lesher, Charles

    2017-04-01

    Basalts are formed by adiabatic decompression melting of the asthenosphere, and thus provide records of the thermal, chemical and dynamical state of the upper mantle. However, uniquely constraining the importance of these factors through the lens of melting is challenging given the inevitability that primary basalts are the product of variable mixing of melts derived from distinct lithologies having different melting behaviors (e.g. peridotite vs. pyroxenite). Forward mantle melting models, such as REEBOX PRO [1], are useful tools in this regard, because they can account for differences in melting behavior and melt pooling processes, and provide estimates of bulk crust composition and volume that can be compared with geochemical and geophysical constraints, respectively. Nevertheless, these models require critical assumptions regarding mantle temperature, and lithologic abundance(s)/composition(s), all of which are poorly constrained. To provide better constraints on these parameters and their uncertainties, we have coupled a Markov Chain Monte Carlo (MCMC) sampling technique with the REEBOX PRO melting model. The MCMC method systematically samples distributions of key REEBOX PRO input parameters (mantle potential temperature, and initial abundances and compositions of the source lithologies) based on a likelihood function that describes the 'fit' of the model outputs (bulk crust composition and volume and end-member peridotite and pyroxenite melts) relative to geochemical and geophysical constraints and their associated uncertainties. As a case study, we have tested and applied the model to magmatism along Reykjanes Peninsula in Iceland, where pyroxenite has been inferred to be present in the mantle source. This locale is ideal because there exist sufficient geochemical and geophysical data to estimate bulk crust compositions and volumes, as well as the range of near-parental melts derived from the mantle. We find that for the case of passive upwelling, the models

  17. Influence of the interplanetary magnetic field on the occurrence and thickness of the plasma mantle

    Science.gov (United States)

    Sckopke, N.; Paschmann, G.; Rosenbauer, H.; Fairfield, D. H.

    1976-01-01

    The response of the plasma mantle to the orientation of the interplanetary magnetic field (IMF) has been studied by correlating Heos 2 plasma and Imp 6 magnetic field data. The mantle is nearly always present when the IMF has a southward component and often also when the field has a weak northward component. In addition, the mantle appears increasingly thicker with greater southward components. On the other hand, the mantle is thin or missing (from the region where it is normally found) when the average IMF has a strong northward component. This result supports the idea that polar cap convection plays a dominant role in the formation of the plasma mantle: mantle plasma originates in the magnetosheath, enters the magnetosphere through the day side polar cusps, and is transported across the cusp to the night side by means of a convection electric field whose magnitude is controlled by the orientation of the IMF.

  18. Non-surgical breast-conservation treatment (KORTUC-BCT) using a new image-guided, enzyme-targeted, and breast cancer stem cell targeted radiosensitization treatment (KORTUC II) for patients with stage I or II breast cancer

    International Nuclear Information System (INIS)

    Ogawa, Yasuhiro; Kubota, Kei; Tadokoro, Michiko

    2012-01-01

    Tumor tissue can be re-oxygenated by inactivating peroxidase/catalase in the tumor tissue through application of hydrogen peroxide. The hydrogen peroxide in turn is then degraded to produce oxygen. In this way, low-LET (linear energy transfer) radioresistant tumors can be transformed into radiosensitive ones (Ogawa Y, et al: Int J Mol Med 12: 453-458, 845-850, 2003, Ogawa Y, et al: Int J Mol Med 14: 397-403, 2004, Kariya S, et al: Int J Radiat Oncol Biol Phys 75: 449-454, 2009). The purpose of the present study was to establish a non-surgical breast-conservation treatment (KORTUC-BCT) by utilizing a novel Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas, Type II (KORTUC II) radiosensitization treatment. KORTUC I was shown to remarkably enhance radiotherapeutic effects in various types of superficially exposed and locally advanced neoplasms (Ogawa Y, et al: Oncol Rep 19: 1389-1394, 2008). Based on clinical experiences using KORTUC I, a new radiosensitizing agent containing hydrogen peroxide and sodium hyaluronate has been developed for intra-tumoral injection in various tumors which are not superficially exposed. The agent is composed of 0.5% hydrogen peroxide and 0.83% sodium hyaluronate (CD44 molecule). Sodium hyaluronate mixed with hydrogen peroxide attaches to CD44-positive tumor cells, which are generally reported to be breast cancer stem cells. This new method, named KORTUC II, was approved by our local ethics committee for treatment of advanced skin cancer (including malignant melanoma), bone/soft tissue malignant neoplasm, breast cancer and metastatic lymph node. A total of 39 early stage breast cancer patients (stage I: 12 patients and stage II: 27) were enrolled in the KORTUC II trial upon fully informed consent. Mean age of the patients was 61.1 years old. All 39 patients were unable or unwilling to undergo surgery and therefore undertook non-surgical breast-conservation treatment (KORTUC-BCT) by KORTUC II. A maximum of 6 ml of the agent was

  19. Subduction to the lower mantle – a comparison between geodynamic and tomographic models

    Directory of Open Access Journals (Sweden)

    T. W. Becker

    2012-11-01

    Full Text Available It is generally believed that subduction of lithospheric slabs is a major contribution to thermal heterogeneity in Earth's entire mantle and provides a main driving force for mantle flow. Mantle structure can, on the one hand, be inferred from plate tectonic models of subduction history and geodynamic models of mantle flow. On the other hand, seismic tomography models provide important information on mantle heterogeneity. Yet, the two kinds of models are only similar on the largest (1000 s of km scales and are quite different in their detailed structure. Here, we provide a quantitative assessment how good a fit can be currently achieved with a simple viscous flow geodynamic model. The discrepancy between geodynamic and tomography models can indicate where further model refinement could possibly yield an improved fit. Our geodynamical model is based on 300 Myr of subduction history inferred from a global plate reconstruction. Density anomalies are inserted into the upper mantle beneath subduction zones, and flow and advection of these anomalies is calculated with a spherical harmonic code for a radial viscosity structure constrained by mineral physics and surface observations. Model viscosities in the upper mantle beneath the lithosphere are ~1020 Pas, and viscosity increases to ~1023 Pas in the lower mantle above D". Comparison with tomography models is assessed in terms of correlation, both overall and as a function of depth and spherical harmonic degree. We find that, compared to previous geodynamic and tomography models, correlation is improved, presumably because of advances in both plate reconstructions and mantle flow computations. However, high correlation is still limited to lowest spherical harmonic degrees. An important ingredient to achieve high correlation – in particular at spherical harmonic degree two – is a basal chemical layer. Subduction shapes this layer into two rather stable hot but chemically dense "piles

  20. Preliminary three-dimensional model of mantle convection with deformable, mobile continental lithosphere

    Science.gov (United States)

    Yoshida, Masaki

    2010-06-01

    Characteristic tectonic structures such as young orogenic belts and suture zones in a continent are expected to be mechanically weaker than the stable part of the continental lithosphere with the cratonic root (or cratonic lithosphere) and yield lateral viscosity variations in the continental lithosphere. In the present-day Earth's lithosphere, the pre-existing, mechanically weak zones emerge as a diffuse plate boundary. However, the dynamic role of a weak (low-viscosity) continental margin (WCM) in the stability of continental lithosphere has not been understood in terms of geophysics. Here, a new numerical simulation model of mantle convection with a compositionally and rheologically heterogeneous, deformable, mobile continental lithosphere is presented for the first time by using three-dimensional regional spherical-shell geometry. A compositionally buoyant and highly viscous continental assemblage with pre-existing WCMs, analogous to the past supercontinent, is modeled and imposed on well-developed mantle convection whose vigor of convection, internal heating rate, and rheological parameters are appropriate for the Earth's mantle. The visco-plastic oceanic lithosphere and the associated subduction of oceanic plates are incorporated. The time integration of the advection of continental materials with zero chemical diffusion is performed by a tracer particle method. The time evolution of mantle convection after setting the model supercontinent is followed over 800 Myr. Earth-like continental drift is successfully reproduced, and the characteristic thermal interaction between the mantle and the continent/supercontinent is observed in my new numerical model. Results reveal that the WCM protects the cratonic lithosphere from being stretched by the convecting mantle and may play a significant role in the stability of the cratonic lithosphere during the geological timescale because it acts as a buffer that prevents the cratonic lithosphere from undergoing global