Tests of equal effect per fraction in microcolony assays of survival after fractionated irradiations
International Nuclear Information System (INIS)
Taylor, J.M.G.
1985-01-01
H.D Thames, Jr. and H.R. Withers propose a test of an equal effect per fraction in microcolony assays after fractionated radiation, in which the total effect is measured by counting microcolonies derived from surviving cells in a tissue. The factors considered to influence the cytocidal effect per fraction are incomplete repair, repopulation, and synchrony. The statistics used in the method are criticized and conditions are given under which the test should not be used. An alternative method of testing for an equal effect per fraction is proposed. The pros and cons of each test are discussed and compared using some mouse jejunal crypt cell survival data
A dose-surviving fraction curve for mouse colonic mucosa
International Nuclear Information System (INIS)
Tucker, S.L.; Thames, H.D. Jr.; Withers, H.R.; Mason, K.A.
1983-01-01
A dose-surviving fraction curve representing the response of the mouse colonic mucosa to single doses of 137 Cs gamma radiation was obtained from the results of a multifraction in vivo colony assay. Construction of the curve required an estimated of the average number of clonogens initially present per colonic crypt. The estimated clonogen count (88) was determined by a statistical method based on the use of doses per fraction common to different fractionation protocols. Parameters for the LQ and TC models of cell survival were obtained by weighted least-squares fits to the data. A comparison of the survival characteristics of cells from the mouse colonic and jejunal crypts suggested that the epithelium of the colon is less radiosensitive than that of the jejunum. (author)
Network meta-analysis of survival data with fractional polynomials
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Jansen Jeroen P
2011-05-01
Full Text Available Abstract Background Pairwise meta-analysis, indirect treatment comparisons and network meta-analysis for aggregate level survival data are often based on the reported hazard ratio, which relies on the proportional hazards assumption. This assumption is implausible when hazard functions intersect, and can have a huge impact on decisions based on comparisons of expected survival, such as cost-effectiveness analysis. Methods As an alternative to network meta-analysis of survival data in which the treatment effect is represented by the constant hazard ratio, a multi-dimensional treatment effect approach is presented. With fractional polynomials the hazard functions of interventions compared in a randomized controlled trial are modeled, and the difference between the parameters of these fractional polynomials within a trial are synthesized (and indirectly compared across studies. Results The proposed models are illustrated with an analysis of survival data in non-small-cell lung cancer. Fixed and random effects first and second order fractional polynomials were evaluated. Conclusion (Network meta-analysis of survival data with models where the treatment effect is represented with several parameters using fractional polynomials can be more closely fitted to the available data than meta-analysis based on the constant hazard ratio.
Network meta-analysis of survival data with fractional polynomials.
Jansen, Jeroen P
2011-05-06
Pairwise meta-analysis, indirect treatment comparisons and network meta-analysis for aggregate level survival data are often based on the reported hazard ratio, which relies on the proportional hazards assumption. This assumption is implausible when hazard functions intersect, and can have a huge impact on decisions based on comparisons of expected survival, such as cost-effectiveness analysis. As an alternative to network meta-analysis of survival data in which the treatment effect is represented by the constant hazard ratio, a multi-dimensional treatment effect approach is presented. With fractional polynomials the hazard functions of interventions compared in a randomized controlled trial are modeled, and the difference between the parameters of these fractional polynomials within a trial are synthesized (and indirectly compared) across studies. The proposed models are illustrated with an analysis of survival data in non-small-cell lung cancer. Fixed and random effects first and second order fractional polynomials were evaluated. (Network) meta-analysis of survival data with models where the treatment effect is represented with several parameters using fractional polynomials can be more closely fitted to the available data than meta-analysis based on the constant hazard ratio.
Fraction V of bovine albumin improves the adherence and survival ...
African Journals Online (AJOL)
Fraction V of bovine albumin improves the adherence and survival of adult rat cerebral cortex neurons in primary culture. ... Because the attack of anoxia and mechanical/chemical force in the course of the single neuron separated from the brain, the adult neocortex neurons may be edema. Since albumin can reduce edema ...
Altered fractionated radiotherapy has a survival benefit for head and neck cancers. Is it true?
International Nuclear Information System (INIS)
Hatano, Kazuo; Sakai, Mitsuhiro; Araki, Hitoshi; Doi, Katsuyuki; Asano, Takanori; Fujikawa, Akira
2007-01-01
There was a significant survival benefit with altered fractionated radiotherapy, corresponding to an absolute benefit of 3.4% at 5 years. The benefit was significantly higher with hyperfractionated radiotherapy (8% at 5 years) than with accelerated radiotherapy (2% with accelerated fractionation without total dose reduction and 1.7% with total dose reduction at 5 years). The effect was greater for the primary tumor than for nodal disease. The effect was also more pronounced in younger patients and in those with good performance status. Hyperfractionation seemed to yield a more consistent advantage for survival than accelerated fractionated radiotherapy. However, accelerated radiotherapy might be associated with higher non-cancer related death. We have to evaluate whether the benefit of hyperfractionated radiotherapy versus standard radiotherapy persists when combined with concomitant chemotherapy and the benefit of intensity-modulated radiation therapy (IMRT) compared with altered fractionation. (author)
Fractionation study: survival of mouse intestinal crypts to exposure of 60Co and 11 MeV electrons
International Nuclear Information System (INIS)
Coffey, C.W.
1975-01-01
The study was conducted to determine a statistical procedure for the quantification of time, dose, fraction relations for mouse intestinal crypt survival after fractionated Co-60 and 11-MeV electron irradiation. In the initial phase of the investigation CDF/1 male mice were exposed to fractionated Co-60 irradiation. A completely randomized experimental design with three factors, total time from initiation to completion of fractionation schedule, number of fractions, and total dose was utilized. The experimental animals were irradiated with a Co-60 panoramic irradiator unit at an absorbed dose rate of approximately 51 rads per minute. Two days after completion of the fractionation schedule, the experimental animals were sacrificed by cervical dislocation. Sections of intestinal jejunum were resected and routine histological preparations performed. The surviving crypts were scored with a compound microscope using a quantitative counting technique. The resulting crypt survival was observed to increase for increasing total times and fraction numbers
Fat Graft Survival After Recipient Site Pretreatment With Fractional Carbon Dioxide Laser.
Kim, Sung-Eun; Lee, Jun Ho; Kim, Tae Gon; Kim, Yong-Ha; Chung, Kyu Jin
2017-12-01
Fat grafting is a commonly performed procedure not only for augmenting the soft tissue but also for regeneration in esthetic and reconstructive plastic surgery.However, unpredictable fat survival rate because of high resorption rate is remained as the main problem. The purpose of this study was to investigate the effect of pretreatment of the recipient site to the fat survival using fractional carbon dioxide (CO2) laser. The rats were divided to 2 groups. Inguinal fat pads of rats were transplanted to the dorsum without pretreatment in the control group. The study group was preconditioned by fractional CO2 laser to the recipient site 1 week before fat graft.The pulse energy was set to 100 mJ. Transplanted fat tissues were harvested at postoperative days 1, 3, 7, 14, and 28 and were analyzed morphologically, histologically, and immunohistochemically. Weight and volume in the control group was more decreased than in the study group at postoperative day 28. Histological evaluation showed less inflammation, less fibrosis, less vacuolization, and better integrity of adipocytes. Immunohistologically, microvessel density in the study group was higher than in the control group (P CO2 laser helped vascularization in the early stage in fat graft and solved the ischemic condition, so it improved fat survival rate.
Influence of radiation fractionation on survival of mice and spleen colony-forming units
International Nuclear Information System (INIS)
Cronkite, E.P.; Bullis, J.E.
1994-01-01
C57B1/6 mice were given Gy X-rays fractionated in several ways. There was a cyclical pattern of animal survival which was correlated to the fractionation interval and which indicated a periodicity of 6 h. Ten grays given a single dose is fatal to 100% of the mice and depresses the CFU-S to about one per leg with no evidence of proliferation during the remaining life. Ten grays given in 2.5-Gy increments at 24-h intervals causes no fatalities and results in a similar CFU-S depression but is followed by an exponential increase in CFU-S over the ensuing 12 days. Although bone marrow from survivors of such treatment was comparable to control marrow in its capacity for short-term rescue, it was clearly, inferior in its capability for long-term rescue. The periodicity of 6 h suggests that the cells responsible for survival of the mice have been synchronized into more or less radiosensitive and radioresistant stages of the cell cycle as a result of the time between the 25-Gy increments. Implications for the CFU-S and long-term repopulating cells are discussed. 22 refs., 5 figs., 1 tab
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Leeman Jonathan E
2012-07-01
Full Text Available Abstract Background Brainstem metastases represent an uncommon clinical presentation that is associated with a poor prognosis. Treatment options are limited given the unacceptable risks associated with surgical resection in this location. However, without local control, symptoms including progressive cranial nerve dysfunction are frequently observed. The objective of this study was to determine the outcomes associated with linear accelerator-based stereotactic radiotherapy or radiosurgery (SRT/SRS of brainstem metastases. Methods We retrospectively reviewed 38 tumors in 36 patients treated with SRT/SRS between February 2003 and December 2011. Treatment was delivered with the Cyberknife™ or Trilogy™ radiosurgical systems. The median age of patients was 62 (range: 28–89. Primary pathologies included 14 lung, 7 breast, 4 colon and 11 others. Sixteen patients (44% had received whole brain radiation therapy (WBRT prior to SRT/SRS; ten had received prior SRT/SRS at a different site (28%. The median tumor volume was 0.94 cm3 (range: 0.01-4.2 with a median prescription dose of 17 Gy (range: 12–24 delivered in 1–5 fractions. Results Median follow-up for the cohort was 3.2 months (range: 0.4-20.6. Nineteen patients (52% had an MRI follow-up available for review. Of these, one patient experienced local failure corresponding to an actuarial 6-month local control of 93%. Fifteen of the patients with available follow-up imaging (79% experienced intracranial failure outside of the treatment volume. The median time to distant intracranial failure was 2.1 months. Six of the 15 patients with distant intracranial failure (40% had received previous WBRT. The actuarial overall survival rates at 6- and 12-months were 27% and 8%, respectively. Predictors of survival included Graded Prognostic Assessment (GPA score, greater number of treatment fractions, and higher prescription dose. Three patients experienced acute treatment-related toxicity consisting of
International Nuclear Information System (INIS)
Tkadlecek, L.; Viklicka, S.; Hofer, M.; Karpfel, Z.
1990-01-01
Mice received doses of 3 Gy of 60 Co-gamma rays total body irradiation at four-day intervals up to a total dose of 24 Gy. After each dose per fraction half of the animals were injected with 10 6 bone marrow cells. At four- and nine-day intervals evaluations were made of the blood count, bone marrow and spleen cellularities, and spleen mass. In animals subjected only to irradiation the damage of hemopoietic organs was becoming deeper until the end of observation; the majority of these mice died by nine days after the irradiation with the last dose per fraction (by 37 days of the experiment). The authors consider anemia as the main cause of their death. All of the mice that were given bone marrow injections survived; nine days after the last dose of irradiation the mean cellularities of their bone marrows and spleens were 76.8% and 112.3% of the unirradiated controls respectively. In general, regeneration of erythropoiesis was quite successful, the number of thrombocytes was positively influenced, and the number of leukocytes nearly unchanged in bone marrow recipients when compared with the only irradiated mice. We observed two periods of maximum and one of minimum bone marrow and spleen regeneration, which were not synchronized. These results deny an unrepairable damage to the hemopoietic microenvironment in conditions of our experiment. This paper follows up with our preceding work describing results of an experiment which ended on day 24. (orig.) [de
International Nuclear Information System (INIS)
Rijn, Johannes van; Berg, Jaap van den; Meijer, Otto W.M.
1995-01-01
Purpose: This study was performed to determine the effects of a continuous exposure to paclitaxel (taxol) in combination with fractionated irradiation on cell proliferation and survival. Methods and Materials: Human lung carcinoma cells (SW1573) were given a daily treatment with 3 Gy of x-rays during 5 days in the continuous presence of 5 nM taxol. The surviving fraction and the total number of cells were determined every 24 h before and immediately after irradiation. Results: Irradiation with 5 x 3 Gy and 5 nM taxol cause approximately the same inhibition of cell proliferation. In combination these treatments have an additional effect and the cell population increases no further after the first 24 h. Whereas the cells become more resistant to taxol after the first 24 h with a minimum survival of 42%, taxol progressively reduces the population of surviving cells in combination with x-rays when the number of fractions increases, up to 25-fold relative to irradiation alone. The enhancement effect of 5 nM taxol is likely to be attributed to an inhibition of the repopulation during fractionated irradiation and not to an increased radiosensitivity. Only after treatment with 10 or 100 nM taxol for 24 h, which is attended with a high cytotoxicity, is moderate radiosensitization observed. Conclusion: Taxol, continuously present at a low concentration with little cytotoxicity, causes a progressive reduction of the surviving cell population in combination with fractionated irradiation, mainly by an inhibition of the repopulation of surviving cells between the dose fractions
A survival model for fractionated radiotherapy with an application to prostate cancer
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Zaider, Marco [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)]. E-mail: Zaiderm@mskcc.org; Zelefsky, Michael J.; Leibel, Steven A. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Hanin, Leonid G. [Department of Mathematics, Idaho State University, Pocatello, ID (United States); Tsodikov, Alexander D.; Yakovlev, Andrei Y. [Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT (United States)
2001-10-01
This paper explores the applicability of a mechanistic survival model, based on the distribution of clonogens surviving a course of fractionated radiation therapy, to clinical data on patients with prostate cancer. The study was carried out using data on 1100 patients with clinically localized prostate cancer who were treated with three-dimensional conformal radiation therapy. The patients were stratified by radiation dose (group 1: <67.5 Gy; group 2: 67.5-72.5 Gy; group 3: 72.5-77.5 Gy; group 4: 77.5-87.5 Gy) and prognosis category (favourable, intermediate and unfavourable as defined by pre-treatment PSA and Gleason score). A relapse was recorded when tumour recurrence was diagnosed or when three successive prostate specific antigen (PSA) elevations were observed from a post-treatment nadir PSA level. PSA relapse-free survival was used as the primary end point. The model, which is based on an iterated Yule process, is specified in terms of three parameters: the mean number of tumour clonogens that survive the treatment, the mean of the progression time of post-treatment tumour development and its standard deviation. The model parameters were estimated by the maximum likelihood method. The fact that the proposed model provides an excellent description both of the survivor function and of the hazard rate is prima facie evidence of the validity of the model because closeness of the two survivor functions (empirical and model-based) does not generally imply closeness of the corresponding hazard rates. The estimated cure probabilities for the favourable group are 0.80, 0.74 and 0.87 (for dose groups 1-3, respectively); for the intermediate group: 0.25, 0.51, 0.58 and 0.78 (for dose groups 1-4, respectively) and for the unfavourable group: 0.0, 0.27, 0.33 and 0.64 (for dose groups 1-4, respectively). The distribution of progression time to tumour relapse was found to be independent of prognosis group but dependent on dose. As the dose increases the mean progression
Cheskes, Sheldon; Schmicker, Robert H; Rea, Tom; Powell, Judy; Drennan, Ian R; Kudenchuk, Peter; Vaillancourt, Christian; Conway, William; Stiell, Ian; Stub, Dion; Davis, Dan; Alexander, Noah; Christenson, Jim
2015-12-01
The role of chest compression fraction (CCF) in resuscitation of shockable out-of-hospital cardiac arrest (OHCA) is uncertain. We evaluated the relationship between CCF and clinical outcomes in a secondary analysis of the Resuscitation Outcomes Consortium PRIMED trial. We included patients presenting in a shockable rhythm who suffered OHCA prior to EMS arrival. Multivariable logistic regression was used to determine the relationship between CCF and survival to hospital discharge, return of spontaneous circulation (ROSC), and neurologically intact survival. We also performed a secondary analysis restricted to patients without ROSC in the first 10 min of EMS resuscitation. Among the 2011 patients, median (IQR) age was 65 (54, 75) years, 78.2% were male, and mean (SD) CCF was 0.71 (0.14). Compared to the reference group (CCFratio (OR) for survival was 0.49 (95% CI: 0.36, 0.68) for CCF 0.60-0.79 and 0.30 (95% CI: 0.20, 0.44) for CCF≥0.80. Results were similar for outcomes of ROSC and neurologically intact survival. Conversely, when restricted to the cohort who did not achieve ROSC during the first 10 min (n=1633), compared to the reference group (CCF<0.60), the OR for survival was 0.79 (95% CI: 0.53, 1.18) for CCF 0.60-0.79 and OR 0.88 (95% CI: 0.56, 1.36) for CCF≥0.80. In this study of OHCA patients presenting in a shockable rhythm, CCF was paradoxically associated with lower odds of survival. CCF is a complex measure and taken by itself may not be a consistent predictor of good clinical outcomes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Radiotherapy. Treatment with high doses per fraction. Lineal-quadratic model of cellular survival
International Nuclear Information System (INIS)
Valls, A.; Ballester, B.
1988-01-01
Over the last years, a significant number of papers have been published in the literature devoted to radiotherapy stating the inefficiency of traditional mathematical models in predicting the biological efficacy of treatment courses with high doses per fraction, and proposing a new model the so-called lineal-quadratic. In this paper the literature is reviewed and some practical examples are presented to illustrate the clinical application of the model. (Author). 15 refs
International Nuclear Information System (INIS)
Kuwahara, Yoshikazu; Mori, Miyuki; Oikawa, Toshiyuki; Shimura, Tsutomu; Fukumoto, Manabu; Ohtake, Yosuke; Ohkubo, Yasuhito; Mori, Shiro
2010-01-01
The high-density survival (HDS) assay was originally elaborated to assess cancer cell responses to therapeutic agents under the influence of intercellular communication. Here, we simplified the original HDS assay and studied its applicability for the detection of cellular radioresistance. We have recently defined clinically relevant radioresistant (CRR) cells, which continue to proliferate with daily exposure to 2 gray (Gy) of X-rays for more than 30 days in vitro. We established human CRR cell lines, HepG2-8960-R from HepG2, and SAS-R1 and -R2 from SAS, respectively. In an attempt to apply the HDS assay to detect radioresistance with clinical relevance, we simplified the original HDS assay by scoring the total number of surviving cells after exposure to X-rays. The modified HDS assay successfully detected radioresistance with clinical relevance. The modified HDS assay detected CRR phenotype, which is not always detectable by clonogenic assay. Therefore, we believe that the modified HDS assay presented in this study is a powerful tool to predict the effectiveness of fractionated radiotherapy against malignant tumors. (author)
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Ziqing Dong
Full Text Available INTRODUCTION: Adipose tissue transplantation is one of the standard procedures for soft-tissue augmentation, reconstruction, and rejuvenation. However, it is unknown as to how the graft survives after transplantation. We thus seek out to investigate the roles of different cellular components in the survival of graft. MATERIALS & METHODS: The ratios of stromal vascular fraction (SVF cellular components from human adipose tissue were evaluated using flow cytometry. Human liposuction aspirates that were either mixed with marked SVF cells or PBS were transplanted into nude mice. The graft was harvested and stained on days 1,4,7 and 14. The inflammation level of both SVF group and Fat-only group were also evaluated. RESULTS: Flow cytometric analysis showed SVF cells mainly contained blood-derived cells, adipose-derived stromal cells (ASCs, and endothelial cells. Our study revealed that most cells are susceptible to death after transplantation, although CD34+ ASCs can remain viable for 14 days. Notably, we found that ASCs migrated to the peripheral edge of the graft. Moreover, the RT-PCR and the immuno-fluorescence examination revealed that although the SVF did not reduce the number of infiltrating immune cells (macrophages in the transplant, it does have an immunoregulatory function of up-regulating the expression of CD163 and CD206 and down-regulating that of IL-1β, IL-6. CONCLUSIONS: Our study suggests that the survival of adipose tissue after nonvascularized adipose transplantation may be due to the ASCs in SVF cells. Additionally, the immunoregulatory function of SVF cells may be indirectly contributing to the remolding of adipose transplant, which may lead to SVF-enriched adipose transplantation.
Li, Feng; Guo, Weihua; Li, Kun; Yu, Mei; Tang, Wei; Wang, Hang; Tian, Weidong
2015-03-01
The success of soft-tissue augmentation is offset by the low survival rates of grafted fat tissue. Research shows that adipose-derived stem cells (ASCs) and platelet-rich plasma (PRP) are beneficial to tissue healing. To evaluate the long-term effects of different volume fractions of PRP combined with ASCs on fat graft. ASCs were isolated from human fat tissue, and PRP was obtained from human blood. Cell count kit-8 and real-time polymerase chain reaction (PCR) were used to evaluate the influence of PRP (0%, 10%, 20%, and 30%; volume/volume [v/v]) in medium on ASC proliferation and adipogenic differentiation, respectively. A novel lipoinjection consisting of granular fat, PRP, and ASCs was subcutaneously transplanted into nude mice. The grafts were volumetrically and histologically evaluated 10, 30, 60, and 90 days after transplantation. The addition of PRP improved ASC proliferation. Expression of adipogenic-related genes, peroxisome proliferator-activated receptor-γ, lipoprotein lipase, and adipophilin were up-regulated in PRP-induced ASCs. Compared with other groups, granular fat grafts formed with 20% (v/v) and 30% (v/v) PRP significantly improved residual volumes. More intact adipocytes and capillary formation, but less vacuolization, were observed in the 20% (v/v) and 30% (v/v) PRP groups at 30, 60, and 90 days. However, no significant difference was observed between the 20% (v/v) and 30% (v/v) PRP groups in retaining fat grafts and improving histology. Fat grafting with 20% (v/v) PRP and ASCs constitutes an appropriate transplantation strategy for improving graft survival and provides a potential approach for soft-tissue restoration in plastic and reconstructive surgery. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.
International Nuclear Information System (INIS)
Wennberg, Berit M.; Baumann, Pia; Gagliardi, Giovanna
2011-01-01
Background. In SBRT of lung tumours no established relationship between dose-volume parameters and the incidence of lung toxicity is found. The aim of this study is to compare the LQ model and the universal survival curve (USC) to calculate biologically equivalent doses in SBRT to see if this will improve knowledge on this relationship. Material and methods. Toxicity data on radiation pneumonitis grade 2 or more (RP2+) from 57 patients were used, 10.5% were diagnosed with RP2+. The lung DVHs were corrected for fractionation (LQ and USC) and analysed with the Lyman- Kutcher-Burman (LKB) model. In the LQ-correction α/β = 3 Gy was used and the USC parameters used were: α/β = 3 Gy, D 0 = 1.0 Gy, n = 10, α 0.206 Gy-1 and d T = 5.8 Gy. In order to understand the relative contribution of different dose levels to the calculated NTCP the concept of fractional NTCP was used. This might give an insight to the questions of whether 'high doses to small volumes' or 'low doses to large volumes' are most important for lung toxicity. Results and Discussion. NTCP analysis with the LKB-model using parameters m = 0.4, D50 = 30 Gy resulted for the volume dependence parameter (n) with LQ correction n = 0.87 and with USC correction n = 0.71. Using parameters m = 0.3, D 50 = 20 Gy n = 0.93 with LQ correction and n 0.83 with USC correction. In SBRT of lung tumours, NTCP modelling of lung toxicity comparing models (LQ,USC) for fractionation correction, shows that low dose contribute less and high dose more to the NTCP when using the USC-model. Comparing NTCP modelling of SBRT data and data from breast cancer, lung cancer and whole lung irradiation implies that the response of the lung is treatment specific. More data are however needed in order to have a more reliable modelling
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Bettington, Catherine S.; Bryant, Guy; Hickey, Brigid; Tripcony, Lee; Pratt, Gary; Fay, Michael
2013-01-01
To compare survival outcomes for two fractionation schedules of thoracic radiotherapy, both given over 3 weeks, in patients with limited stage small cell lung cancer (LS-SCLC). At Radiation Oncology Mater Centre (ROMC) and the Royal Brisbane and Women's Hospital (RBWH), patients with LS-SCLC treated with curative intent are given radiotherapy (with concurrent chemotherapy) to a dose of either 40Gy in 15 fractions ('the 40Gy/15⧣group') or 45Gy in 30 fractions ('the 45Gy/30⧣group'). The choice largely depends on institutional preference. Both these schedules are given over 3 weeks, using daily and twice-daily fractionation respectively. The records of all such patients treated from January 2000 to July 2009 were retrospectively reviewed and survival outcomes between the two groups compared. Of 118 eligible patients, there were 38 patients in the 40Gy/15⧣ group and 41 patients in the 45Gy/30⧣ group. The median relapse-free survival time was 12 months in both groups. Median overall survival was 21 months (95% CI 2–37 months) in the 40Gy/15⧣ group and 26 months (95% CI 1–48 months) in the 45Gy/30⧣ group. The 5-year overall survival rates were 20% and 25%, respectively (P=0.24). On multivariate analysis, factors influencing overall survival were: whether prophylactic cranial irradiation (PCI) was given (P=0.01) and whether salvage chemotherapy was given at the time of relapse (P=0.057). Given the small sample size, the potential for selection bias and the retrospective nature of our study it is not possible to draw firm conclusions regarding the efficacy of hypofractionated thoracic radiotherapy compared with hyperfractionated accelerated thoracic radiotherapy however hypofractionated radiotherapy may result in equivalent relapse-free survival.
Militello, Carmelo; Rundo, Leonardo; Conti, Vincenzo; Minafra, Luigi; Cammarata, Francesco Paolo; Mauri, Giancarlo; Gilardi, Maria Carla; Porcino, Nunziatina
2017-10-01
The current methodology for the Surviving Fraction (SF) measurement in clonogenic assay, which is a technique to study the anti-proliferative effect of treatments on cell cultures, involves manual counting of cell colony forming units. This procedure is operator-dependent and error-prone. Moreover, the identification of the exact colony number is often not feasible due to the high growth rate leading to the adjacent colony merging. As a matter of fact, conventional assessment does not deal with the colony size, which is generally correlated with the delivered radiation dose or the administered cytotoxic agent. Considering that the Area Covered by Colony (ACC) is proportional to the colony number and size as well as to the growth rate, we propose a novel fully automatic approach exploiting Circle Hough Transform, to automatically detect the wells in the plate, and local adaptive thresholding, which calculates the percentage of ACC for the SF quantification. This measurement relies just on this covering percentage and does not consider the colony number, preventing inconsistencies due to intra- and inter-operator variability. To evaluate the accuracy of the proposed approach, we compared the SFs obtained by our automatic ACC-based method against the conventional counting procedure. The achieved results (r = 0.9791 and r = 0.9682 on MCF7 and MCF10A cells, respectively) showed values highly correlated with the measurements using the traditional approach based on colony number alone. The proposed computer-assisted methodology could be integrated in laboratory practice as an expert system for the SF evaluation in clonogenic assays. Copyright © 2017 Elsevier Ltd. All rights reserved.
Lanni, Thomas B; Grills, Inga S; Kestin, Larry L; Robertson, John M
2011-10-01
Radiation therapy (RT) is the standard alternative curative treatment option for medically inoperable early stage non-small-cell lung cancer (NSCLC). Recently, stereotactic body radiotherapy (SBRT) has shown substantial promise to improve local control rates as compared with conventional fractionated RT [external beam RT (EBRT)]. We compare treatment outcomes and costs between SBRT and EBRT in this patient population. A total of 86 patients with Stage I (Tl-2 N0) NSCLC were treated with either EBRT (n=41) or SBRT (n=45) between January 2002 and April 2008. EBRT patients were treated to a median dose of 70 Gy with 3-dimensional conformal RT (n=39) or intensity-modulated radiation therapy (n=2). SBRT was delivered in 4 or 5 fractions to 48 (Tl, n=44) or 60 (T2, n=1) Gy. The actual cost was calculated using 2010 Medicare hospital-based Ambulatory Payment Classification and hospital-based physician fee screen reimbursement rates for both the technical and professional components. On the basis of a median number of fractions for this patient population, SBRT was significantly less expensive ($13,639 EBRT vs. $10,616 SBRT, P < 0.01). Survival analysis demonstrated superior 36-month overall survival using SBRT, 71% versus 42% for EBRT (P < 0.05). SBRT also reduced local failure by nearly 3 times compared with EBRT (12% vs. 34%, P=0.10). In this study of Stage I NSCLC patients, SBRT was found to be less expensive than standard fractionated EBRT, with the cost savings highly dependent on the number of SBRT fractions and EBRT technique (3-dimensional conformal RT vs. intensity-modulated radiation therapy). SBRT was also associated with superior local control and overall survival.
Ludwig, Johannes M; Ambinder, Emily McIntosh; Ghodadra, Anish; Xing, Minzhi; Prajapati, Hasmukh J; Kim, Hyun S
2016-07-01
To investigate survival outcomes following radioembolization with Yttrium-90 (Y90) for neuroendocrine tumor liver metastases (NETLMs). This study was designed to assess the efficacy of Y90 radioembolization and to evaluate lung shunt fraction (LSF) as a predictor for survival. A single-center, prospective study of 44 consecutive patients (median age: 58.5 years, 29.5 % male) diagnosed with pancreatic (52.3 %) or carcinoid (47.7 %) NETLMs from 2006 to 2012 who underwent Y90 radioembolization was performed. Patients' baseline characteristics, including LSF and median overall survival (OS) from first Y90 radioembolization, were recorded and compared between patients with high (≥10 %) and low (1.2 mg (p = 0.016), and lack of pretreatment with octreotide (p = 0.01) as independent prognostic factors for poorer survival. Tumor type and total radiation dose did not predict survival. LSF ≥10 %, elevated bilirubin levels, and lack of pretreatment with octreotide were found to be independent prognostic factors for poorer survival in patients with NETLMs.
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Puncharas Gorcharoenwat
2015-01-01
Full Text Available Effects of temperature and water soluble fraction (WSF of biodiesel and diesel on hatchability and survival of early stage Macrobrachium rosenbergii were investigated at the temperature of 25, 28, 31 and 34oC. The purpose of this study was to determine toxic effects of biodiesel and diesel on incubation period, hatchability, and survival of the first larval stage. The results showed a significant difference of incubation period among temperatures. The highest temperature (34°C resulted in the shortest incubation period (15 days while the lowest temperature (25°C gave the longest incubation period (19 days. One hundred percent of hatchability was found at temperature 28 and 31°C in the control group. The lowest hatchability occurred at 100% of WSF of palm biodiesel. The hatchability and survival of eggs through the first stage larvae in control and WSF of biodiesel decreased in higher temperature. However, in 50% WSF of diesel, the highest temperature (34°C increased the hatchability and survival whereas 100% WSF of diesel, no larval survival could be found. In comparison between WSF of biodiesel and diesel on newly hatched larvae, the diesel was more toxic to the larvae than that of the biodiesel. Regarding temperature and WSF of biodiesel and diesel effects on the first larval stage of M. rosenbergii, clearly diesel was more harmful to the larvae than biodiesel.
International Nuclear Information System (INIS)
Deeg, H.J.; Storb, R.; Weiden, P.L.; Schumacher, D.; Shulman, H.; Graham, T.; Thomas, E.D.
1981-01-01
Beagle dogs treated by total-body irradiation (TBI) were given autologous marrow grafts in order to avoid death from marrow toxicity. Acute and delayed non-marrow toxicities of high single-dose (27 dogs) and fractionated TBI (20 dogs) delivered at 0.05 or 0.1 Gy/min were compared. Fractionated TBI was given in increments of 2 Gy every 6 hr for three increments per day. Acute toxicity and early mortality (<1 month) at identical total irradiation doses were comparable for dogs given fractionated or single-dose TBI. With single-dose TBI, 14, 16, and 18 Gy, respectively, given at 0.05 Gy/min, 0/5, 5/5, and 2/2 dogs died from acute toxicity; with 10, 12, and 14 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 5/5 dogs died acutely. With fractionated TBI, 14 and 16 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 2/2 dogs died auctely. Early deaths were due to radiation enteritis with or without associated septicemia (29 dogs; less than or equal to Day 10). Three dogs given 10 Gy of TBI at 0.1 Gy/min died from bacterial pneumonia; one (Day 18) had been given fractionated and two (Days 14, 22) single-dose TBI. Fifteen dogs survived beyond 1 month; eight of these had single-dose TBI (10-14 Gy) and all died within 7 months of irradiation from a syndrome consisting of hepatic damage, pancreatic fibrosis, malnutrition, wasting, and anemia. Seven of the 15 had fractionated TBI, and only one (14 Gy) died on Day 33 from hepatic failure, whereas 6 (10-14 Gy) are alive and well 250 to 500 days after irradiation. In conclusion, fractionated TBI did not offer advantages over single-dose TBI with regard to acute toxicity and early mortality; rather, these were dependent upon the total dose of TBI. The total acutely tolerated dose was dependent upon the exposure rate; however, only dogs given fractionated TBI became healthy long-term survivors
Directory of Open Access Journals (Sweden)
Sarah Flora Jonas
Full Text Available In cross-sectional studies of time-to-event data collected by patient examinations at a single random point in time, a fraction of them will not experience the event regardless of the length of the follow-up time. This is the case in clinical immunology studies that include a mixed population, with both immune-reactive and immune-tolerant (or non-susceptible patients. In these cases, classical tests of current status data may perform poorly. New methods for testing these data are needed.In the two-sample comparison setting, we propose a score test for testing the null hypothesis that survival does not differ in either the non-susceptible fraction or the time-to-event distribution among the susceptible fraction.In a wide range of scenarios, simulation results show interesting improvements in power for the proposed score test compared to the logrank-type test in most of the configurations we investigated. In a cross-sectional study of drug immunogenicity among treated multiple sclerosis patients, the proposed score test reveals that gender is associated with the immunogenicity of interferon.
Kim, Deok-Yeol; Ji, Yi-Hwa; Kim, Deok-Woo; Dhong, Eun-Sang; Yoon, Eul-Sik
2014-11-01
Traditional adipose tissue transplantation has unpredictable viability and poor absorption rates. Recent studies have reported that treatment with platelet-rich plasma (PRP), adipose-derived stem cells (ASCs), and stromal vascular fraction (SVF) are related to increased survival of grafted adipose tissue. This study was the first simultaneous comparison of graft survival in combination with PRP, ASCs, and SVF. Adipose tissues were mixed with each other, injected subcutaneously into the back of nude mice, and evaluated at 4, 8, and 12 weeks. Human adipocytes were grossly maintained in the ASCs and SVF mixtures. Survival of the adipose tissues with PRP was observed at 4 weeks and with SVF at 8 and 12 weeks. At 12 weeks, volume reduction in the ASCs and SVF mixtures were 36.9% and 32.1%, respectively, which were significantly different from that of the control group without adjuvant treatment, 51.0%. Neovascular structures were rarely observed in any of the groups. Our results suggest that the technique of adding ASCs or SVF to transplanted adipose tissue might be more effective than the conventional grafting method. An autologous adipose tissue graft in combination with ASCs or SVF may potentially contribute to stabilization of engraftment.
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Ludwig, Johannes M. [Yale University, Division of Interventional Radiology, Department of Radiology and Biomedical Imaging (United States); Ambinder, Emily McIntosh [John Hopkins University School of Medicine, Department of Diagnostic Radiology (United States); Ghodadra, Anish [University of Pittsburgh School of Medicine, Interventional Radiology, Department of Radiology (United States); Xing, Minzhi [Yale University, Division of Interventional Radiology, Department of Radiology and Biomedical Imaging (United States); Prajapati, Hasmukh J. [The University of Tennessee Health Science Center, Division of Interventional Radiology, Department of Radiology (United States); Kim, Hyun S., E-mail: kevin.kim@yale.edu [Yale University, Division of Interventional Radiology, Department of Radiology and Biomedical Imaging (United States)
2016-07-15
ObjectiveTo investigate survival outcomes following radioembolization with Yttrium-90 (Y90) for neuroendocrine tumor liver metastases (NETLMs). This study was designed to assess the efficacy of Y90 radioembolization and to evaluate lung shunt fraction (LSF) as a predictor for survival.MethodsA single-center, prospective study of 44 consecutive patients (median age: 58.5 years, 29.5 % male) diagnosed with pancreatic (52.3 %) or carcinoid (47.7 %) NETLMs from 2006 to 2012 who underwent Y90 radioembolization was performed. Patients’ baseline characteristics, including LSF and median overall survival (OS) from first Y90 radioembolization, were recorded and compared between patients with high (≥10 %) and low (<10 %) LSF. Baseline comparisons were performed using Fisher’s exact tests for categorical and Mann–Whitney U test for continuous variables. Survival was calculated using the Kaplan–Meier method. Univariate (Wilcoxon rank-sum test) and multivariate analyses (Cox Proportional Hazard Model) for risk factor analysis were performed.ResultsThere was no statistically significant difference in age, gender, race, tumor properties, or previous treatments between patients with high (n = 15) and low (n = 29) LSF. The median OS was 27.4 months (95 %CI 12.73–55.23), with 4.77 months (95 %CI 2.87–26.73) for high and 42.77 months (95 %CI 18.47–59.73) for low LSF (p = 0.003). Multivariate analysis identified high LSF (p = 0.001), total serum bilirubin >1.2 mg (p = 0.016), and lack of pretreatment with octreotide (p = 0.01) as independent prognostic factors for poorer survival. Tumor type and total radiation dose did not predict survival.ConclusionsLSF ≥10 %, elevated bilirubin levels, and lack of pretreatment with octreotide were found to be independent prognostic factors for poorer survival in patients with NETLMs.
Shimura, Tsutomu; Kakuda, Satoshi; Ochiai, Yasushi; Kuwahara, Yoshikazu; Takai, Yoshihiro; Fukumoto, Manabu
2011-06-01
Radioresistance is a major cause of treatment failure of radiotherapy (RT) in human cancer. We have recently revealed that acquired radioresistance of tumor cells induced by fractionated radiation is attributable to cyclin D1 overexpression as a consequence of the downregulation of GSK3β-dependent cyclin D1 proteolysis mediated by a constitutively activated serine-threonine kinase, AKT. This prompted us to hypothesize that targeting the AKT/GSK3β/cyclin D1 pathway may improve fractionated RT by suppressing acquired radioresistance of tumor cells. Two human tumor cell lines with acquired radioresistance were exposed to X-rays after incubation with either an AKT inhibitor, AKT/PKB signaling inhibitor-2 (API-2), or a Cdk4 inhibitor (Cdk4-I). Cells were then subjected to immunoblotting, clonogenic survival assay, cell growth analysis, and cell death analysis with TUNEL and annexin V staining. In vivo radiosensitivity was assessed by growth of human tumors xenografted into nude mice. Treatment with API-2 resulted in downregulation of cyclin D1 expression in cells with acquired radioresistance. Cellular radioresistance disappeared completely both in vitro and in vivo with accompanying apoptosis when treated with API-2. Furthermore, inhibition of cyclin D1/Cdk4 by Cdk4-I was sufficient for abolishing radioresistance. Treatment with either API-2 or Cdk4-I was also effective in suppressing resistance to cis-platinum (II)-diamine-dichloride in the cells with acquired radioresistance. Interestingly, the radiosensitizing effect of API-2 was canceled by overexpression of cyclin D1 whereas Cdk4-I was still able to sensitize cells with cyclin D1 overexpression. Cyclin D1/Cdk4 is a critical target of the AKT survival signaling pathway responsible for tumor radioresistance. Targeting the AKT/GSK3β/cyclin D1/Cdk4 pathway would provide a novel approach to improve fractionated RT and would have an impact on tumor eradication in combination with chemotherapy. Copyright © 2011
Directory of Open Access Journals (Sweden)
Kuhlmann Jan
2012-07-01
Full Text Available Abstract Background We recently showed that LOH proximal to M6P/IGF2R locus (D6S1581 in primary ovarian tumors is predictive for the presence of disseminated tumor cells (DTC in the bone marrow (BM. For therapy-monitoring, it would be highly desirable to establish a blood-based biomarker. Therefore, we quantified circulating DNA (cirDNA in sera of 63 ovarian cancer patients before surgery and after chemotherapy, measured incidence of LOH at four cancer-relevant chromosomal loci, correlated LOH with tumor cell spread to the BM and evaluated prognostic significance of LOH. Methods cirDNA was fractionated into high- and low molecular-weight fraction (HMWF, LMWF for LOH-profiling, utilizing PCR-based fluorescence microsatellite analysis. BM aspirates were analyzed for DTC by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3. Results cirDNA levels in the HMWF before surgery were predictive for residual tumor load (p = 0.017. After chemotherapy, we observed a significant decline of cirDNA in the LMWF (p = 0.0001 but not in the HMWF. LOH was prevalently detected in the LMWF with an overall frequency of 67%, only moderately ablating after chemotherapy (45%. Before surgery, LOH in the LMWF at marker D10S1765 and D13S218 significantly correlated with tumor grading and FIGO stage (p = 0.033, p = 0.004, respectively. In both combined fractions, LOH at D6S1581 additionally associated with overall survival (OS (p = 0.030. Moreover, solely LOH at D10S1765 in LMWF after therapy correlated with DTC in BM after therapy (p = 0.017. Conclusion We demonstrate the applicability and necessity of DNA-fractionation prior to analyzing circulating LOH and identify LOH at D10S1765 and D6S1581 as novel blood-based biomarkers for ovarian cancer, being relevant for therapy-monitoring.
International Nuclear Information System (INIS)
Hagemann, G.
1976-01-01
By means of a quantitative analysis, the time dependency of the number of dead cells and the resulting statement of cell numbers are compared with colony survival curves and with the distribution of colony sizes. The obtained periodical variation of reproductively killed cells is analyzed through population kinetics and is reduced to the number of those among the irradiated cells which show radiation-induced lethal reproductive damage. Therefrom, together with both sorts of interphase-dead cells, the dose dependency of the three lethal fractions results, taking into consideration the quantitative cellular statement. The formation of maxima of reproductively killed cells at the intervals of generation time until F 3 -generation is explained by an autosynchronization of partly lethally injured cell populations. From colony size distributions a linear dose dependency of the mean colony size group can be derived; this is discussed in connection with DNA double strand breaks regarded as a possible cause of reproductive lethal damages. The data obtained concerning the development of a cell population with radiation damages are evaluated by the construction of phylogenetic schedules for every 300 rd and 500 rd. By this means, the underlying population kinetics is being revised quantitatively. (orig.) [de
Jones, Heather A.; Huq, M. Saiful; Smith, Ryan P.
2013-01-01
The study is designed to investigate the effect of edema on the delivered dose, tumor cell surviving fraction (SF), and tumor control probability (TCP) in the patients of prostate cancer who underwent 131Cs permanent seed implantation. The dose reduction, the SF, and the TCP for edematous prostate implants were calculated for 31 patients who underwent real‐time 131Cs permanent seed implantation for edema half‐lives (EHL), ranging from 4 days to 34 days and for edema magnitudes (M0) varying from 5% to 60% of the actual prostate volume. A dose reduction in 131Cs implants varied from 1.1% (for EHL=4 days and M0=5%) to 32.3% (for EHL=34 days and M0=60%). These are higher than the dose reduction in 125I implants, which vary from 0.3% (for EHL=4 days and M0=5%) to 17.5% (for EHL=34 days and M0=60%). As EHL increased from 4 days to 34 days and edema magnitude increased from 5% to 60%, the natural logarithmic value of SF increased by 4.57 and the TCP decreased by 0.80. Edema induced increase in the SF and decrease in the TCP in 131Cs seed implants, is significantly more pronounced in a combination of higher edema magnitude and larger edema half‐lives than for less edema magnitude and lower edema half‐lives, as compared for M0=60% and EHL=34, and M0=5% and EHL=4 days. PACS number: 87.53.Jw PMID:23318378
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Akabani, Gamal [Department of Radiology, Duke University Medical Center, P.O. Box 3808, Durham, NC 27710 (United States); Carlin, Sean [Department of Radiology, Duke University Medical Center, P.O. Box 3808, Durham, NC 27710 (United States); Welsh, Phil [Department of Radiology, Duke University Medical Center, P.O. Box 3808, Durham, NC 27710 (United States); Zalutsky, Michael R. [Department of Radiology, Duke University Medical Center, P.O. Box 3808, Durham, NC 27710 (United States)]. E-mail: zalut001@mc.duke.edu
2006-04-15
Introduction: Radioimmunotherapy with anti-HER2 monoclonal antibodies (mAbs) such as trastuzumab is a promising strategy for treating HER2-positive breast and ovarian carcinoma patients. The objective of this study was to determine the cytotoxic effectiveness of trastuzumab labeled with the 7.2-h half-life {alpha}-particle emitter {sup 211}At. Methods: Experiments were performed on SKBr-3, BT-474 and the transfected MCF7/HER2-18 human breast carcinoma cell lines. Intrinsic radiosensitivity was determined after exposure to external beam irradiation. The cytotoxicity of {sup 211}At-labeled trastuzumab was measured by clonogenic assays. The distribution of HER2 receptor expression on the cell lines was measured using fluorescence-activated cell sorting. A pharmacokinetic (PK)/microdosimetric model was established to assess the effects of specific activity (SA), HER2 receptor expression and absorbed dose on survival fraction (SF). Results: With external beam irradiation, the 2-Gy SF for BT-474, SKBr-3 and MCF7/HER2-18 cells was 0.78, 0.53 and 0.64 Gy, respectively. Heterogeneous HER2 expression was observed, with a subpopulation of cells lacking measurable receptor (14.5%, SKBr-3; 0.34%, MCF-7/HER2; 1.73%, BT-474). When plotted as a function of activity concentration, SF curves were biphasic and inversely proportional to SA; however, when the model was applied and absorbed doses calculated, the SF curve was monoexponential independent of SA. Thus, the PK model was able to demonstrate the effects of competition between cold and labeled mAb. These studies showed that the relative biological effectiveness of {sup 211}At-labeled trastuzaumab was about 10 times higher than that of external beam therapy. Conclusion: These in vitro studies showed that {sup 211}At-labeled trastuzumab mAb is an effective cytotoxic agent for the treatment of HER2-positive tumor cells. The SA of the labeled mAb and the homogeneity of HER2 receptor expression are important variables influencing
DEFF Research Database (Denmark)
Melchior, T; Gadsbøll, N; Hildebrandt, P
1996-01-01
was found to have a significant association with long-term mortality after myocardial infarction, that was independent of age, history of hypertension, congestive heart failure symptoms during hospitalization or of either left or right ventricular ejection fractions at discharge. We conclude that the excess......Patients with diabetes mellitus have a high morbidity and mortality from acute myocardial infarction, the reason for which is not fully understood. The relationship between congestive heart failure symptoms, left ventricular ejection fraction, and long-term mortality was examined in 578 hospital...... survivors of acute myocardial infarction, 47 of whom had Type 2 (non-insulin-dependent) diabetes mellitus. None of the patients were treated with insulin. The prevalence of congestive heart failure during hospitalization was similar in patients with and without diabetes, although mean diuretic dose...
DEFF Research Database (Denmark)
Melchior, T; Gadsbøll, N; Hildebrandt, P
1996-01-01
Patients with diabetes mellitus have a high morbidity and mortality from acute myocardial infarction, the reason for which is not fully understood. The relationship between congestive heart failure symptoms, left ventricular ejection fraction, and long-term mortality was examined in 578 hospital ......-insulin-dependent diabetes mellitus might indicate that heart failure, it present, is more severe in patients with than in those without diabetes. The importance of diastolic dysfunction in this context needs to be determined....
Wolff, Georg; Dimitroulis, Dimitrios; Andreotti, Felicita; Kołodziejczak, Michalina; Jung, Christian; Scicchitano, Pietro; Devito, Fiorella; Zito, Annapaola; Occhipinti, Michele; Castiglioni, Battistina; Calveri, Giuseppe; Maisano, Francesco; Ciccone, Marco M; De Servi, Stefano; Navarese, Eliano P
2017-01-01
Heart failure with reduced ejection fraction caused by ischemic heart disease is associated with increased morbidity and mortality. It remains unclear whether revascularization by either coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) carries benefits or risks in this group of stable patients compared with medical treatment. We performed a meta-analysis of available studies comparing different methods of revascularization (PCI or CABG) against each other or medical treatment in patients with coronary artery disease and left ventricular ejection fraction ≤40%. The primary outcome was all-cause mortality; myocardial infarction, revascularization, and stroke were also analyzed. Twenty-one studies involving a total of 16 191 patients were included. Compared with medical treatment, there was a significant mortality reduction with CABG (hazard ratio, 0.66; 95% confidence interval, 0.61-0.72; Pdisease and reduced ejection fraction. Between the 2 revascularization strategies, CABG seems more favorable compared with PCI in this particular clinical setting. © 2017 American Heart Association, Inc.
Akita, Keitaro; Kohno, Takashi; Kohsaka, Shun; Shiraishi, Yasuyuki; Nagatomo, Yuji; Izumi, Yuki; Goda, Ayumi; Mizuno, Atsushi; Sawano, Mitsuaki; Inohara, Taku; Fukuda, Keiichi; Yoshikawa, Tsutomu
2017-05-15
Acute heart failure (HF) is a frequently encountered cardiac condition. Its prevalence increases exponentially with age. In spite of this, elderly patients are underrepresented in clinical trials and the implementation of guideline-based medical therapy (GBMT) in them is not well established. We investigated the current use of GBMT and its effects on mortality and HF rehospitalization among elderly patients with acute HF with reduced ejection fraction (HFrEF) using data obtained from a contemporary multi-center registry. We analyzed data from 1,441 consecutive acute HF patients registered in the West Tokyo Heart Failure (WET-HF) registry (mean age 73.2 ± 13.6 years). Reduced ejection fraction (<45%) was noted in 803 patients (55.7%), of which 237 were aged ≥80 years (elderly group). The prescription rate of GBMT (use of renin-angiotensin system inhibitors and β-blockers at discharge) was significantly lower in the elderly than in the younger (aged < 80 years) group (46.8% vs. 66.9%, p<0.001). Although GBMT at discharge was associated with reductions in HF readmission or the composite endpoint of cardiac death and HF readmission (HR 0.49, 95% CI 0.30-0.80; and HR 0.53, 95% CI 0.32-0.89, respectively) in the younger group, this association was not observed in the elderly group (HR 1.41, 95% CI 0.68-2.92; and HR 1.54, 95% CI 0.76-3.13, respectively) CONCLUSIONS: GBMT implementation in elderly patients with HFrEF was found to be suboptimal. However, the underuse of GBMT did not appear to be responsible for poorer outcomes in elderly HFrEF patients. Further research is required to establish an ideal therapeutic approach for this population. URL: http://www.umin.ac.jp/icdr/index-j.html. Unique identifier: UMIN000001171. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.
Regnault, Veronique; Lagrange, Jérémy; Pizard, Anne; Safar, Michel E; Fay, Renaud; Pitt, Bertram; Challande, Pascal; Rossignol, Patrick; Zannad, Faiez; Lacolley, Patrick
2014-01-01
Although hypertension contributes significantly to worsen cardiovascular risk, blood pressure increment in subjects with heart failure is paradoxically associated with lower risk. The objective was to determine whether pulse pressure and pulse wave velocity (PWV) remain prognostic markers, independent of treatment in heart failure with reduced left ventricular function. The investigation involved 6632 patients of the Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study. All subjects had acute myocardial infarction with left ventricular ejection fraction <40% and signs/symptoms of heart failure. Carotid-femoral PWV was measured in a subpopulation of 306 subjects. In the overall population, baseline mean arterial pressure <90 mm Hg was associated with higher all-cause death (hazard ratio, 1.14 [95% confidence interval, 1.00-1.30]; P<0.05), whereas higher left ventricular ejection fraction or pulse pressure was associated with lower rates of all-cause death, cardiovascular death/hospitalization, and cardiovascular death. In the subpopulation, increased baseline PWV was associated with worse outcomes (all-cause death: 1.16 [1.03-1.30]; P<0.05 and cardiovascular deaths: 1.16 [1.03-1.31]; P<0.05), independent of age and left ventricular ejection fraction. Using multiple regression analysis, systolic blood pressure and age were the main independent factors positively associated with pulse pressure or PWV, both in the entire population or in the PWV substudy. In heart failure and low ejection fraction, our results suggest that pulse pressure, being negatively associated with outcome, is more dependent on left ventricular function and thereby no longer a marker of aortic elasticity. In contrast, increased aortic stiffness, assessed by PWV, contributes significantly to cardiovascular death.
International Nuclear Information System (INIS)
Kim, Y; Waldron, T; Pennington, E
2016-01-01
Purpose: To test the radiobiological impact of hypofractionated choroidal melanoma brachytherapy, we calculated single fraction equivalent doses (SFED) of the tumor that equivalent to 85 Gy of I125-BT for 20 patients. Corresponding organs-at-risks (OARs) doses were estimated. Methods: Twenty patients treated with I125-BT were retrospectively examined. The tumor SFED values were calculated from tumor BED using a conventional linear-quadratic (L-Q) model and an universal survival curve (USC). The opposite retina (α/β = 2.58), macula (2.58), optic disc (1.75), and lens (1.2) were examined. The % doses of OARs over tumor doses were assumed to be the same as for a single fraction delivery. The OAR SFED values were converted into BED and equivalent dose in 2 Gy fraction (EQD2) by using both L-Q and USC models, then compared to I125-BT. Results: The USC-based BED and EQD2 doses of the macula, optic disc, and the lens were on average 118 ± 46% (p < 0.0527), 126 ± 43% (p < 0.0354), and 112 ± 32% (p < 0.0265) higher than those of I125-BT, respectively. The BED and EQD2 doses of the opposite retina were 52 ± 9% lower than I125-BT. The tumor SFED values were 25.2 ± 3.3 Gy and 29.1 ± 2.5 Gy when using USC and LQ models which can be delivered within 1 hour. All BED and EQD2 values using L-Q model were significantly larger when compared to the USC model (p < 0.0274) due to its large single fraction size (> 14 Gy). Conclusion: The estimated single fraction doses were feasible to be delivered within 1 hour using a high dose rate source such as electronic brachytherapy (eBT). However, the estimated OAR doses using eBT were 112 ∼ 118% higher than when using the I125-BT technique. Continued exploration of alternative dose rate or fractionation schedules should be followed.
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Kim, Y; Waldron, T; Pennington, E [University Of Iowa, College of Medicine, Iowa City, IA (United States)
2016-06-15
Purpose: To test the radiobiological impact of hypofractionated choroidal melanoma brachytherapy, we calculated single fraction equivalent doses (SFED) of the tumor that equivalent to 85 Gy of I125-BT for 20 patients. Corresponding organs-at-risks (OARs) doses were estimated. Methods: Twenty patients treated with I125-BT were retrospectively examined. The tumor SFED values were calculated from tumor BED using a conventional linear-quadratic (L-Q) model and an universal survival curve (USC). The opposite retina (α/β = 2.58), macula (2.58), optic disc (1.75), and lens (1.2) were examined. The % doses of OARs over tumor doses were assumed to be the same as for a single fraction delivery. The OAR SFED values were converted into BED and equivalent dose in 2 Gy fraction (EQD2) by using both L-Q and USC models, then compared to I125-BT. Results: The USC-based BED and EQD2 doses of the macula, optic disc, and the lens were on average 118 ± 46% (p < 0.0527), 126 ± 43% (p < 0.0354), and 112 ± 32% (p < 0.0265) higher than those of I125-BT, respectively. The BED and EQD2 doses of the opposite retina were 52 ± 9% lower than I125-BT. The tumor SFED values were 25.2 ± 3.3 Gy and 29.1 ± 2.5 Gy when using USC and LQ models which can be delivered within 1 hour. All BED and EQD2 values using L-Q model were significantly larger when compared to the USC model (p < 0.0274) due to its large single fraction size (> 14 Gy). Conclusion: The estimated single fraction doses were feasible to be delivered within 1 hour using a high dose rate source such as electronic brachytherapy (eBT). However, the estimated OAR doses using eBT were 112 ∼ 118% higher than when using the I125-BT technique. Continued exploration of alternative dose rate or fractionation schedules should be followed.
Maria Klimikova
2010-01-01
Understanding the reasons of the present financial problems lies In understanding the substance of fractional reserve banking. The substance of fractional banking is in lending more money than the bankers have. Banking of partial reserves is an alternative form which links deposit banking and credit banking. Fractional banking is causing many unfavorable economic impacts in the worldwide system, specifically an inflation.
Povstenko, Yuriy
2015-01-01
This book is devoted to fractional thermoelasticity, i.e. thermoelasticity based on the heat conduction equation with differential operators of fractional order. Readers will discover how time-fractional differential operators describe memory effects and space-fractional differential operators deal with the long-range interaction. Fractional calculus, generalized Fourier law, axisymmetric and central symmetric problems and many relevant equations are featured in the book. The latest developments in the field are included and the reader is brought up to date with current research. The book contains a large number of figures, to show the characteristic features of temperature and stress distributions and to represent the whole spectrum of order of fractional operators. This work presents a picture of the state-of-the-art of fractional thermoelasticity and is suitable for specialists in applied mathematics, physics, geophysics, elasticity, thermoelasticity and engineering sciences. Corresponding sections of ...
International Nuclear Information System (INIS)
Saminadayar, L.
2001-01-01
20 years ago fractional charges were imagined to explain values of conductivity in some materials. Recent experiments have proved the existence of charges whose value is the third of the electron charge. This article presents the experimental facts that have led theorists to predict the existence of fractional charges from the motion of quasi-particles in a linear chain of poly-acetylene to the quantum Hall effect. According to the latest theories, fractional charges are neither bosons nor fermions but anyons, they are submitted to an exclusive principle that is less stringent than that for fermions. (A.C.)
International Nuclear Information System (INIS)
Pouliliou, Stamatia E.; Lialiaris, Theodoros S.; Dimitriou, Thespis; Giatromanolaki, Alexandra; Papazoglou, Dimitrios; Pappa, Aglaia; Pistevou, Kyriaki; Kalamida, Dimitra; Koukourakis, Michael I.
2015-01-01
Purpose: Predictive assays for acute radiation toxicities would be clinically relevant in radiation oncology. We prospectively examined the predictive role of the survival fraction at 2 Gy (SF2) and of γH2AX (double-strand break [DSB] DNA marker) expression kinetics in peripheral blood mononuclear cells (PBMCs) from cancer patients before radiation therapy. Methods and Materials: SF2 was measured with Trypan Blue assay in the PBMCs from 89 cancer patients undergoing radiation therapy at 4 hours (SF2 [4h] ) and 24 hours (SF2 [24h] ) after ex vivo irradiation. Using Western blot analysis and band densitometry, we further assessed the expression of γH2AX in PBMC DNA at 0 hours, 30 minutes, and 4 hours (33 patients) and 0 hour, 4 hours, and 24 hours (56 patients), following ex vivo irradiation with 2 Gy. Appropriate ratios were used to characterize each patient, and these were retrospectively correlated with early radiation therapy toxicity grade. Results: The SF2 (4h) was inversely correlated with the toxicity grade (P=.006). The γH2AX-ratio (30min) (band density of irradiated/non-irradiated cells at 30 minutes) revealed, similarly, a significant inverse association (P=.0001). The DSB DNA repair rate from 30 minutes to 4 hours, calculated as the relative RγH2AX-ratio (γH2AX-ratio (4h) /γH2AX-ratio (30min) ) showed a significant direct association with high toxicity grade (P=.01). Conclusions: Our results suggest that SF2 is a significant radiation sensitivity index for patients undergoing radiation therapy. γH2AX Western blot densitometry analysis provided 2 important markers of normal tissue radiation sensitivity. Low γH2AX expression at 30 minutes was linked with high toxicity grade, suggesting that poor γH2AX repair activity within a time frame of 30 minutes after irradiation predicts for poor radiation tolerance. On the other hand, rapid γH2AX content restoration at 4 hours after irradiation, compatible with efficient DSB repair ability
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Pouliliou, Stamatia E. [Department of Radiotherapy/Oncology, Radiobiology and Radiopathology Unit, School of Health Sciences, Democritus University of Thrace, Alexandroupolis (Greece); Lialiaris, Theodoros S. [Department of Medical Genetics, School of Health Sciences, Democritus University of Thrace, Alexandroupolis (Greece); Dimitriou, Thespis [Department of Anatomy, School of Health Sciences, Democritus University of Thrace, Alexandroupolis (Greece); Giatromanolaki, Alexandra [Department of Pathology, School of Health Sciences, Democritus University of Thrace, Alexandroupolis (Greece); Papazoglou, Dimitrios [Department of Internal Medicine, School of Health Sciences, Democritus University of Thrace, Alexandroupolis (Greece); Pappa, Aglaia [Department of Molecular Biology and Genetics, School of Health Sciences, Democritus University of Thrace, Alexandroupolis (Greece); Pistevou, Kyriaki [Department of Radiotherapy/Oncology, Aristotle University of Thessalonica, Thessalonica (Greece); Kalamida, Dimitra [Department of Radiotherapy/Oncology, Radiobiology and Radiopathology Unit, School of Health Sciences, Democritus University of Thrace, Alexandroupolis (Greece); Koukourakis, Michael I., E-mail: targ@her.forthnet.gr [Department of Radiotherapy/Oncology, Radiobiology and Radiopathology Unit, School of Health Sciences, Democritus University of Thrace, Alexandroupolis (Greece)
2015-07-01
Purpose: Predictive assays for acute radiation toxicities would be clinically relevant in radiation oncology. We prospectively examined the predictive role of the survival fraction at 2 Gy (SF2) and of γH2AX (double-strand break [DSB] DNA marker) expression kinetics in peripheral blood mononuclear cells (PBMCs) from cancer patients before radiation therapy. Methods and Materials: SF2 was measured with Trypan Blue assay in the PBMCs from 89 cancer patients undergoing radiation therapy at 4 hours (SF2{sub [4h]}) and 24 hours (SF2{sub [24h]}) after ex vivo irradiation. Using Western blot analysis and band densitometry, we further assessed the expression of γH2AX in PBMC DNA at 0 hours, 30 minutes, and 4 hours (33 patients) and 0 hour, 4 hours, and 24 hours (56 patients), following ex vivo irradiation with 2 Gy. Appropriate ratios were used to characterize each patient, and these were retrospectively correlated with early radiation therapy toxicity grade. Results: The SF2{sub (4h)} was inversely correlated with the toxicity grade (P=.006). The γH2AX-ratio{sub (30min)} (band density of irradiated/non-irradiated cells at 30 minutes) revealed, similarly, a significant inverse association (P=.0001). The DSB DNA repair rate from 30 minutes to 4 hours, calculated as the relative RγH2AX-ratio (γH2AX-ratio{sub (4h)}/γH2AX-ratio{sub (30min)}) showed a significant direct association with high toxicity grade (P=.01). Conclusions: Our results suggest that SF2 is a significant radiation sensitivity index for patients undergoing radiation therapy. γH2AX Western blot densitometry analysis provided 2 important markers of normal tissue radiation sensitivity. Low γH2AX expression at 30 minutes was linked with high toxicity grade, suggesting that poor γH2AX repair activity within a time frame of 30 minutes after irradiation predicts for poor radiation tolerance. On the other hand, rapid γH2AX content restoration at 4 hours after irradiation, compatible with
Bhattacharyya, Sonalee; Namakshi, Nama; Zunker, Christina; Warshauer, Hiroko K.; Warshauer, Max
2016-01-01
Making math more engaging for students is a challenge that every teacher faces on a daily basis. These authors write that they are constantly searching for rich problem-solving tasks that cover the necessary content, develop critical-thinking skills, and engage student interest. The Mystery Fraction activity provided here focuses on a key number…
Wang, Baoyong; Zheng, Chunfang; Sankoff, David
2011-01-01
Abstract Background Paralog reduction, the loss of duplicate genes after whole genome duplication (WGD) is a pervasive process. Whether this loss proceeds gene by gene or through deletion of multi-gene DNA segments is controversial, as is the question of fractionation bias, namely whether one homeologous chromosome is more vulnerable to gene deletion than the other. Results As a null hypothesis, we first assume deletion events, on one homeolog only, excise a geometrically distributed number o...
International Nuclear Information System (INIS)
Badwe, R.A.
1999-01-01
The primary endpoint in the majority of the studies has been either disease recurrence or death. This kind of analysis requires a special method since all patients in the study experience the endpoint. The standard method for estimating such survival distribution is Kaplan Meier method. The survival function is defined as the proportion of individuals who survive beyond certain time. Multi-variate comparison for survival has been carried out with Cox's proportional hazard model
Fractional Vector Calculus and Fractional Special Function
Li, Ming-Fan; Ren, Ji-Rong; Zhu, Tao
2010-01-01
Fractional vector calculus is discussed in the spherical coordinate framework. A variation of the Legendre equation and fractional Bessel equation are solved by series expansion and numerically. Finally, we generalize the hypergeometric functions.
Sinha, Navita
Mars is one of the suitable bodies in our solar system that can accommodate extraterrestrial life. The detection of plumes of methane in the Martian atmosphere, geochemical evidence, indication of flow of intermittent liquid water on the Martian surface, and geomorphologies of Mars have bolstered the plausibility of finding extant or evidence of extinct life on its surface and/or subsurface. However, contemporary Mars has been considered as an inhospitable planet for several reasons, such as low atmospheric surface pressure, low surface temperature, and intense DNA damaging radiation. Despite the hostile conditions of Mars, a few strains of methanogenic archaea have shown survivability in limited surface and subsurface conditions of Mars. Methanogens, which are chemolithoautotrophic non-photosynthetic anaerobic archaea, have been considered ideal models for possible Martian life forms for a long time. The search for biosignatures in the Martian atmosphere and possibility of life on the Martian surface under UVC radiation and deep subsurface under high pressure, temperature, and various pHs are the motivations of this research. Analogous to Earth, Martian atmospheric methane could be biological in origin. Chapter 1 provides relevant information about Mars' habitability, methane on Mars, and different strains of methanogens used in this study. Chapter 2 describes the interpretation of the carbon isotopic data of biogenic methane produced by methanogens grown on various Mars analogs and the results provide clues to determine ambiguous sources of methane on Mars. Chapter 3 illustrates the sensitivity of hydrated and desiccated cultures of halophilic and non-halophilic methanogens to DNA-damaging ultraviolet radiations, and the results imply that UVC radiation may not be an enormous constraint for methanogenic life forms on the surface of Mars. Chapters 4, 5, and 6 discuss the data for the survivability, growth, and morphology of methanogens in presumed deep subsurface
Energy Technology Data Exchange (ETDEWEB)
Kearny, C.H.
2002-06-24
The purpose of this book is to provide Americans with information and instructions that will significantly increase their chances of surviving a possible nuclear attack. It brings together field-tested instructions that, if followed by a large fraction of Americans during a crisis that preceded an attack, could save millions of lives. The author is convinced that the vulnerability of our country to nuclear threat or attack must be reduced and that the wide dissemination of the information contained in this book would help achieve that objective of our overall defense strategy.
DEFF Research Database (Denmark)
Ashauer, Roman; Albert, Carlo; Augustine, Starrlight
2016-01-01
well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates...
Miller, Rupert G
2011-01-01
A concise summary of the statistical methods used in the analysis of survival data with censoring. Emphasizes recently developed nonparametric techniques. Outlines methods in detail and illustrates them with actual data. Discusses the theory behind each method. Includes numerous worked problems and numerical exercises.
Hypo fractionated radiotherapy in advanced lung cancer
International Nuclear Information System (INIS)
Andrade Carvalho, Heloisa de; Saito, Newton Heitetsu; Gomes, Herbeni Cardoso; Aguilar, Patricia Bailao; Nadalin, Wladimir
1996-01-01
Patients with advanced lung cancers have bad prognosis and, many times, are submitted to prolonged and not always efficient treatments. We present a study where 51 patients were treated with hypo fractionated radiotherapy, based on two distinct schemes, according to the performance status and social conditions of each patient: continuous treatment: 30 Gy, 10 fractions of 3 Gy, 5 days/week (37 cases); weekly treatment: 30 Gy, 6 fractions of 5 Gy, once a week (14 cases). Symptoms relief and impact in survival were evaluated. In both groups, we observed improvement of symptoms in about 70% of the occurrences with a medium survival of three months. We conclude that hypo fractionation is an effective palliative treatment for lung cancers, in patients with short life-expectancy and must be considered as a option in advanced cases, in patients with short life-expectancy that deserve some kind of treatment. (author). 37 refs., 2 tabs
Initialized Fractional Calculus
Lorenzo, Carl F.; Hartley, Tom T.
2000-01-01
This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.
Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua
2015-07-01
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.
Energy Technology Data Exchange (ETDEWEB)
Sabzikar, Farzad, E-mail: sabzika2@stt.msu.edu [Department of Statistics and Probability, Michigan State University, East Lansing, MI 48823 (United States); Meerschaert, Mark M., E-mail: mcubed@stt.msu.edu [Department of Statistics and Probability, Michigan State University, East Lansing, MI 48823 (United States); Chen, Jinghua, E-mail: cjhdzdz@163.com [School of Sciences, Jimei University, Xiamen, Fujian, 361021 (China)
2015-07-15
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.
MEERSCHAERT, MARK M.; SABZIKAR, FARZAD; CHEN, JINGHUA
2014-01-01
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series. PMID:26085690
Meerschaert, Mark M; Sabzikar, Farzad; Chen, Jinghua
2015-07-15
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.
MEERSCHAERT, MARK M.; SABZIKAR, FARZAD; CHEN, JINGHUA
2015-01-01
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly obs...
fractional differential equations
Indian Academy of Sciences (India)
We apply this method for solving space–time fractional Cahn--Allen equation and space--time fractional Klein–Gordon equation. The fractional derivatives are described in the sense of modified Riemann--Lioville. As a result of some exact solution in the form of hyperbolic, trigonometric and rational solutions are deduced.
Unfolding Fraction Multiplication
Wyberg, Terry; Whitney, Stephanie R.; Cramer, Kathleen A.; Monson, Debra S.; Leavitt, Seth
2011-01-01
Students often have difficulty understanding fractions, in general, and understanding how to multiply fractions, in particular. To move past this potential problem area, students need to develop a deeper understanding of multiplication and connect the ideas to fractions. In this article, the authors share their insights into teaching fraction…
Shamim, Atif
2011-03-01
For the first time, a generalized Smith chart is introduced here to represent fractional order circuit elements. It is shown that the standard Smith chart is a special case of the generalized fractional order Smith chart. With illustrations drawn for both the conventional integer based lumped elements and the fractional elements, a graphical technique supported by the analytical method is presented to plot impedances on the fractional Smith chart. The concept is then applied towards impedance matching networks, where the fractional approach proves to be much more versatile and results in a single element matching network for a complex load as compared to the two elements in the conventional approach. © 2010 IEEE.
Dey, Aloke
2009-01-01
A one-stop reference to fractional factorials and related orthogonal arrays.Presenting one of the most dynamic areas of statistical research, this book offers a systematic, rigorous, and up-to-date treatment of fractional factorial designs and related combinatorial mathematics. Leading statisticians Aloke Dey and Rahul Mukerjee consolidate vast amounts of material from the professional literature--expertly weaving fractional replication, orthogonal arrays, and optimality aspects. They develop the basic theory of fractional factorials using the calculus of factorial arrangements, thereby providing a unified approach to the study of fractional factorial plans. An indispensable guide for statisticians in research and industry as well as for graduate students, Fractional Factorial Plans features: * Construction procedures of symmetric and asymmetric orthogonal arrays. * Many up-to-date research results on nonexistence. * A chapter on optimal fractional factorials not based on orthogonal arrays. * Trend-free plans...
Fractional Dynamics and Control
Machado, José; Luo, Albert
2012-01-01
Fractional Dynamics and Control provides a comprehensive overview of recent advances in the areas of nonlinear dynamics, vibration and control with analytical, numerical, and experimental results. This book provides an overview of recent discoveries in fractional control, delves into fractional variational principles and differential equations, and applies advanced techniques in fractional calculus to solving complicated mathematical and physical problems.Finally, this book also discusses the role that fractional order modeling can play in complex systems for engineering and science. Discusses how fractional dynamics and control can be used to solve nonlinear science and complexity issues Shows how fractional differential equations and models can be used to solve turbulence and wave equations in mechanics and gravity theories and Schrodinger’s equation Presents factional relaxation modeling of dielectric materials and wave equations for dielectrics Develops new methods for control and synchronization of...
Fraction V of bovine albumin improves the adherence and survival ...
African Journals Online (AJOL)
STORAGESEVER
2009-02-04
Feb 4, 2009 ... Primary embryonic or young neuronal cells are used to study physiology or pathology of neurons. However, they are not optimal as a model for age-related changes in physiology or late-onset disease. Successful culturing of neurons from adult animals, however, has been historically difficult. Because.
Fractionated stereotactic radiotherapy of small intracranial malignancies
International Nuclear Information System (INIS)
Tokuuye, Koichi; Akine, Yasuyuki; Sumi, Minako; Kagami, Yoshikazu; Murayama, Shigeyuki; Nakayama, Hidetsugu; Ikeda, Hiroshi; Tanaka, Minoru; Shibui, Soichiro; Nomura, Kazuhiro
1998-01-01
Purpose: To retrospectively evaluate the effectiveness of fractionated stereotactic radiotherapy (FSRT) in patients with small intracranial malignancies. Methods and Materials: From July 1991 to March 1997, 80 patients with a total of 121 brain or skull-base tumors were treated with FSRT alone, and were followed for periods ranging from 3 to 62 months (median 9.8). The majority of patients received 42 Gy in 7 fractions over 2.3 weeks, but in July 1993, protocols using smaller fraction doses were introduced for patients whose radiation-field diameters were larger than 3 cm or whose tumors were close to critical normal tissues. Results: For 64 patients with metastatic brain tumors the overall median survival was 8.3 months and 1-year actuarial survival rate was 33%. Significant prognostic factors were: the presence of extracranial tumors, pre-treatment performance status, and the lung as a primary site. Patients without extracranial tumors prior to FSRT had a median survival of 21.2 months. For seven patients with high-grade glioma, 1-year actuarial local control rate was 75%, with a median survival of 10.3 months. For patients with skull-base tumors the local control was achieved in 6 of 6 patients (100%), with a median survival of 30.7 months. No one suffered from acute complications, but three patients, two of whom had undergone FSRT as the third course of radiotherapy, developed late radiation injuries. Conclusion: Overall high local control and low morbidity rates suggest that FSRT is an effective and safe modality, even for those with a history of prior irradiation. However, patients with risk factors should be treated with smaller fraction doses
Sadik, N
1992-12-01
The global population growth rate has been 1.7% since 1975, while for developing countries it is 2.1%. UN projections are for population to grow from 5.5 billion in 1992 to 10 billion by 2050. Sustainable development is only possible when population growth is balanced with available resources. UN medium population projections of 7.8 billion by 2050 can be reached with 187 million more couples practicing family planning (FP) by the year 2000. Within the past 20 years, 1 billion people, mostly from developed countries, have enjoyed economic growth, but have contributed polluting technologies, excessive waste, and environmentally dangerous economic practices. The generations to come will be affected by the continuance of these practices by the 1 billion affluent population. The bottom billion are mired in poverty and high population growth and survival, needs that hinder their country's economic development, upset fragile ecosystems, and destroy the balance between human beings and the environment. International migration on a large scale could be the by-product of population growth. Progress has been made since the 1974 UN Conference on Population in Bucharest. There are still, however, vulnerable populations, the poorest households, the landless and small-holder families, urban squatters and slum dwellers, those living in low lying deltas and along coasts, and women. Women control family resources and their micro environment. Sustainable development is not possible without the elimination of prejudice against women. Reproductive freedom for women must be a priority. High quality, readily available FP services are also needed for those desiring this. The difficulty is in providing FP services that conform to a woman's social and cultural background and personal needs; success is dependent on involving women in the process and holding men more responsible for FP. Development means allowing for the legitimate aspirations of the majority not just the specialized
Fractional and noncommutative spacetimes
Arzano, M.|info:eu-repo/dai/nl/32616443X; Calcagni, M.; Oriti, D.; Scalisi, M.
2011-01-01
We establish a mapping between fractional and noncommutative spacetimes in configuration space. Depending on the scale at which the relation is considered, there arise two possibilities. For a fractional spacetime with log-oscillatory measure, the effective measure near the fundamental scale
A.I. Barros (Ana); J.B.G. Frenk (Hans); J.A.S. Gromicho (Joaquim)
1997-01-01
textabstractIn this paper we analyze some variants of the classical uncapacitated facility location problem with a ratio as an objective function. Using basic concepts and results of fractional programming, we identify a class of one-level fractional location problems which can be solved in
Wilkerson, Trena L.; Bryan, Tommy; Curry, Jane
2012-01-01
This article describes how using candy bars as models gives sixth-grade students a taste for learning to represent fractions whose denominators are factors of twelve. Using paper models of the candy bars, students explored and compared fractions. They noticed fewer different representations for one-third than for one-half. The authors conclude…
Diaz, Victor Alfonzo; Giusti, Andrea
2018-03-01
The aim of this paper is to present a simple generalization of bosonic string theory in the framework of the theory of fractional variational problems. Specifically, we present a fractional extension of the Polyakov action, for which we compute the general form of the equations of motion and discuss the connection between the new fractional action and a generalization the Nambu-Goto action. Consequently, we analyze the symmetries of the modified Polyakov action and try to fix the gauge, following the classical procedures. Then we solve the equations of motion in a simplified setting. Finally, we present a Hamiltonian description of the classical fractional bosonic string and introduce the fractional light-cone gauge. It is important to remark that, throughout the whole paper, we thoroughly discuss how to recover the known results as an "integer" limit of the presented model.
Fractional Order Generalized Information
Directory of Open Access Journals (Sweden)
José Tenreiro Machado
2014-04-01
Full Text Available This paper formulates a novel expression for entropy inspired in the properties of Fractional Calculus. The characteristics of the generalized fractional entropy are tested both in standard probability distributions and real world data series. The results reveal that tuning the fractional order allow an high sensitivity to the signal evolution, which is useful in describing the dynamics of complex systems. The concepts are also extended to relative distances and tested with several sets of data, confirming the goodness of the generalization.
FRACTIONS: CONCEPTUAL AND DIDACTIC ASPECTS
Directory of Open Access Journals (Sweden)
Sead Rešić
2016-09-01
Full Text Available Fractions represent the manner of writing parts of whole numbers (integers. Rules for operations with fractions differ from rules for operations with integers. Students face difficulties in understanding fractions, especially operations with fractions. These difficulties are well known in didactics of Mathematics throughout the world and there is a lot of research regarding problems in learning about fractions. Methods for facilitating understanding fractions have been discovered, which are essentially related to visualizing operations with fractions.
Fractional Stochastic Field Theory
Honkonen, Juha
2018-02-01
Models describing evolution of physical, chemical, biological, social and financial processes are often formulated as differential equations with the understanding that they are large-scale equations for averages of quantities describing intrinsically random processes. Explicit account of randomness may lead to significant changes in the asymptotic behaviour (anomalous scaling) in such models especially in low spatial dimensions, which in many cases may be captured with the use of the renormalization group. Anomalous scaling and memory effects may also be introduced with the use of fractional derivatives and fractional noise. Construction of renormalized stochastic field theory with fractional derivatives and fractional noise in the underlying stochastic differential equations and master equations and the interplay between fluctuation-induced and built-in anomalous scaling behaviour is reviewed and discussed.
Social Trust and Fractionalization:
DEFF Research Database (Denmark)
Bjørnskov, Christian
2008-01-01
a much larger country sample than in previous literature confirms that fractionalization in the form of income inequality and political diversity adversely affects social trust while ethnic diversity does not. However, these effects differ systematically across countries, questioning standard...
Fractional excretion of sodium
FE sodium; FENa ... a lab. There, they are examined for salt (sodium) and creatinine levels. Creatinine is a chemical waste ... Chernecky CC, Berger BJ. Excretion fraction of filtered sodium-blood and urine. In: Chernecky CC, Berger BJ, ...
Goodrich, Christopher
2015-01-01
This text provides the first comprehensive treatment of the discrete fractional calculus. Experienced researchers will find the text useful as a reference for discrete fractional calculus and topics of current interest. Students who are interested in learning about discrete fractional calculus will find this text to provide a useful starting point. Several exercises are offered at the end of each chapter and select answers have been provided at the end of the book. The presentation of the content is designed to give ample flexibility for potential use in a myriad of courses and for independent study. The novel approach taken by the authors includes a simultaneous treatment of the fractional- and integer-order difference calculus (on a variety of time scales, including both the usual forward and backwards difference operators). The reader will acquire a solid foundation in the classical topics of the discrete calculus while being introduced to exciting recent developments, bringing them to the frontiers of the...
The Local Fractional Bootstrap
DEFF Research Database (Denmark)
Bennedsen, Mikkel; Hounyo, Ulrich; Lunde, Asger
new resampling method, the local fractional bootstrap, relies on simulating an auxiliary fractional Brownian motion that mimics the fine properties of high frequency differences of the Brownian semistationary process under the null hypothesis. We prove the first order validity of the bootstrap method...... to two empirical data sets: we assess the roughness of a time series of high-frequency asset prices and we test the validity of Kolmogorov's scaling law in atmospheric turbulence data....
Intracellular Cadmium Isotope Fractionation
Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.
2011-12-01
Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.
Series expansion in fractional calculus and fractional differential equations
Li, Ming-Fan; Ren, Ji-Rong; Zhu, Tao
2009-01-01
Fractional calculus is the calculus of differentiation and integration of non-integer orders. In a recently paper (Annals of Physics 323 (2008) 2756-2778), the Fundamental Theorem of Fractional Calculus is highlighted. Based on this theorem, in this paper we introduce fractional series expansion method to fractional calculus. We define a kind of fractional Taylor series of an infinitely fractionally-differentiable function. Further, based on our definition we generalize hypergeometric functio...
Fractional calculus in pharmacokinetics.
Sopasakis, Pantelis; Sarimveis, Haralambos; Macheras, Panos; Dokoumetzidis, Aristides
2018-02-01
We are witnessing the birth of a new variety of pharmacokinetics where non-integer-order differential equations are employed to study the time course of drugs in the body: this is dubbed "fractional pharmacokinetics". The presence of fractional kinetics has important clinical implications such as the lack of a half-life, observed, for example with the drug amiodarone and the associated irregular accumulation patterns following constant and multiple-dose administration. Building models that accurately reflect this behaviour is essential for the design of less toxic and more effective drug administration protocols and devices. This article introduces the readers to the theory of fractional pharmacokinetics and the research challenges that arise. After a short introduction to the concepts of fractional calculus, and the main applications that have appeared in literature up to date, we address two important aspects. First, numerical methods that allow us to simulate fractional order systems accurately and second, optimal control methodologies that can be used to design dosing regimens to individuals and populations.
FRACTIONS: CONCEPTUAL AND DIDACTIC ASPECTS
Sead Rešić; Ismet Botonjić; Maid Omerović
2016-01-01
Fractions represent the manner of writing parts of whole numbers (integers). Rules for operations with fractions differ from rules for operations with integers. Students face difficulties in understanding fractions, especially operations with fractions. These difficulties are well known in didactics of Mathematics throughout the world and there is a lot of research regarding problems in learning about fractions. Methods for facilitating understanding fractions have been discovered...
Biswas, Karabi; Caponetto, Riccardo; Mendes Lopes, António; Tenreiro Machado, José António
2017-01-01
This book focuses on two specific areas related to fractional order systems – the realization of physical devices characterized by non-integer order impedance, usually called fractional-order elements (FOEs); and the characterization of vegetable tissues via electrical impedance spectroscopy (EIS) – and provides readers with new tools for designing new types of integrated circuits. The majority of the book addresses FOEs. The interest in these topics is related to the need to produce “analogue” electronic devices characterized by non-integer order impedance, and to the characterization of natural phenomena, which are systems with memory or aftereffects and for which the fractional-order calculus tool is the ideal choice for analysis. FOEs represent the building blocks for designing and realizing analogue integrated electronic circuits, which the authors believe hold the potential for a wealth of mass-market applications. The freedom to choose either an integer- or non-integer-order analogue integrator...
FRACTIONAL CRYSTALLIZATION FEED ENVELOPE
International Nuclear Information System (INIS)
HERTING DL
2008-01-01
Laboratory work was completed on a set of evaporation tests designed to establish a feed envelope for the fractional crystallization process. The feed envelope defines chemical concentration limits within which the process can be operated successfully. All 38 runs in the half-factorial design matrix were completed successfully, based on the qualitative definition of success. There is no feed composition likely to be derived from saltcake dissolution that would cause the fractional crystallization process to not meet acceptable performance requirements. However, some compositions clearly would provide more successful operation than other compositions
Apoptotic potential and cell sensitivity to fractionated radiotherapy
International Nuclear Information System (INIS)
Rupnow, Brent A.; Murtha, Albert D.; Alarcon, Rodolfo M.; Giaccia, Amato J.; Knox, Susan J.
1997-01-01
Purpose/Objective: At present, the relationship between sensitivity to radiation-induced apoptosis and overall cellular radiosensitivity remains unclear. In particular, the relationship of apoptotic sensitivity to the survival of cells following fractionated irradiation has not been well studied. The purpose of the present study was to determine if increasing cell sensitivity to radiation-induced apoptosis would result in decreased clonogenic survival following single dose and fractionated irradiation in vitro. Materials and Methods: To address this, we chose a cell line (Rat-1MycER) in which the sensitivity to radiation-induced apoptosis could be altered by switching on or off the activity of a conditional c-Myc allele (c-MycER). The c-MycER construct expresses a full length c-Myc protein fused to a modified hormone binding domain of the estrogen receptor. Only in the presence of the estrogen analog 4-hydroxytamoxifen (4HT), does the conditional c-MycER become active. Apoptosis following irradiation in these cells (with and without c-MycER activation) was analyzed by flow cytometry to determine the percentage of cells undergoing apoptosis following various radiation doses and at different times after irradiation. Additionally, clonogenic survival analysis was performed following single radiation doses from 0 to 10 Gy and following five fractions of 2 or 4 Gy each. Survival of cells with and without c-MycER activation was compared. Furthermore, the effect of overexpressing the anti-apoptotic Bcl-2 gene on apoptosis induction and clonogenic survival of these cells was examined. Results: Rat-1MycER cells were strongly sensitized to radiation-induced apoptosis in a dose and time dependent manner when MycER was activated relative to cells treated without c-MycER activation. This c-Myc-mediated sensitivity to radiation-induced apoptosis was suppressed by overexpression of the anti-apoptotic protein Bcl-2. In addition to increasing apoptosis, activating c-MycER prior to
Vinogradova, Natalya; Blaine, Larry
2013-01-01
Almost everyone loves chocolate. However, the same cannot be said about fractions, which are loved by markedly fewer. Middle school students tend to view them with wary respect, but little affection. The authors attempt to sweeten the subject by describing a type of game involving division of chocolate bars. The activity they describe provides a…
Fractional Differential Equation
Directory of Open Access Journals (Sweden)
Moustafa El-Shahed
2007-01-01
where 2<α<3 is a real number and D0+α is the standard Riemann-Liouville fractional derivative. Our analysis relies on Krasnoselskiis fixed point theorem of cone preserving operators. An example is also given to illustrate the main results.
Nonlinear fractional relaxation
Indian Academy of Sciences (India)
Abstract. We define a nonlinear model for fractional relaxation phenomena. We use ε-expansion method to analyse this model. By studying the fundamental solutions of this model we find that when t → 0 the model exhibits a fast decay rate and when t → ∞ the model exhibits a power-law decay. By analysing the frequency ...
Vapor liquid fraction determination
International Nuclear Information System (INIS)
1980-01-01
This invention describes a method of measuring liquid and vapor fractions in a non-homogeneous fluid flowing through an elongate conduit, such as may be required with boiling water, non-boiling turbulent flows, fluidized bed experiments, water-gas mixing analysis, and nuclear plant cooling. (UK)
Brewing with fractionated barley
Donkelaar, van L.H.G.
2016-01-01
Brewing with fractionated barley
Beer is a globally consumed beverage, which is produced from malted barley, water, hops and yeast. In recent years, the use of unmalted barley and exogenous enzymes have become more popular because they enable simpler processing and reduced environmental
Fermion Number Fractionization
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 8. Fermion Number Fractionization. Kumar Rao Narendra Sahu Prasanta K ... Author Affiliations. Kumar Rao1 Narendra Sahu1 Prasanta K Panigrahi1. Theoretical Physics Division, Physical Research Laboratory, Ahmedabad 380 009, India ...
Brewing with fractionated barley
Donkelaar, van L.H.G.
2016-01-01
Brewing with fractionated barley Beer is a globally consumed beverage, which is produced from malted barley, water, hops and yeast. In recent years, the use of unmalted barley and exogenous enzymes have become more popular because they enable simpler processing and reduced environmental impact. Raw
Survival pathways under stress
Indian Academy of Sciences (India)
First page Back Continue Last page Graphics. Survival pathways under stress. Bacteria survive by changing gene expression. pattern. Three important pathways will be discussed: Stringent response. Quorum sensing. Proteins performing function to control oxidative damage.
Fractional Poisson Fields and Martingales
Aletti, Giacomo; Leonenko, Nikolai; Merzbach, Ely
2018-01-01
We present new properties for the Fractional Poisson process (FPP) and the Fractional Poisson field on the plane. A martingale characterization for FPPs is given. We extend this result to Fractional Poisson fields, obtaining some other characterizations. The fractional differential equations are studied. We consider a more general Mixed-Fractional Poisson process and show that this process is the stochastic solution of a system of fractional differential-difference equations. Finally, we give some simulations of the Fractional Poisson field on the plane.
Fractional Poisson Fields and Martingales
Aletti, Giacomo; Leonenko, Nikolai; Merzbach, Ely
2018-02-01
We present new properties for the Fractional Poisson process (FPP) and the Fractional Poisson field on the plane. A martingale characterization for FPPs is given. We extend this result to Fractional Poisson fields, obtaining some other characterizations. The fractional differential equations are studied. We consider a more general Mixed-Fractional Poisson process and show that this process is the stochastic solution of a system of fractional differential-difference equations. Finally, we give some simulations of the Fractional Poisson field on the plane.
-Dimensional Fractional Lagrange's Inversion Theorem
Directory of Open Access Journals (Sweden)
F. A. Abd El-Salam
2013-01-01
Full Text Available Using Riemann-Liouville fractional differential operator, a fractional extension of the Lagrange inversion theorem and related formulas are developed. The required basic definitions, lemmas, and theorems in the fractional calculus are presented. A fractional form of Lagrange's expansion for one implicitly defined independent variable is obtained. Then, a fractional version of Lagrange's expansion in more than one unknown function is generalized. For extending the treatment in higher dimensions, some relevant vectors and tensors definitions and notations are presented. A fractional Taylor expansion of a function of -dimensional polyadics is derived. A fractional -dimensional Lagrange inversion theorem is proved.
Gauge invariant fractional electromagnetic fields
Energy Technology Data Exchange (ETDEWEB)
Lazo, Matheus Jatkoske, E-mail: matheuslazo@furg.br [Instituto de Matematica, Estatistica e Fisica - FURG, Rio Grande, RS (Brazil)
2011-09-26
Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators. -- Highlights: → We propose a fractional Lagrangian formulation for fractional Maxwell's fields. → We obtain gauge invariant fractional electromagnetic fields. → Our generalized fractional Maxwell's field is spatially symmetrical. → We discuss the non-causality of the theory.
Fractionalization and Entrepreneurial Activities
Awaworyi Churchill, Sefa
2015-01-01
The vast majority of the literature on ethnicity and entrepreneurship focuses on the construct of ethnic entrepreneurship. However, very little is known about how ethnic heterogeneity affects entrepreneurship. This study attempts to fill the gap, and thus examines the effect of ethnic heterogeneity on entrepreneurial activities in a cross-section of 90 countries. Using indices of ethnic and linguistic fractionalization, we show that ethnic heterogeneity negatively influences entrepreneurship....
International Nuclear Information System (INIS)
Gindele, S.
1984-01-01
For the study of the dependence of the radiation effects on the stem cells of the small intestine mucous membrane on dose fractionation mice from the strain C3H were exposed to a one-time irradiation, an irradiation in three fractions, five fractions on one day, five fractions on two days and an irradiation in ten fractions. It was shown, that the survival curves for the higher fractionation numbers were shifted to the right from the ones with higher total doses and have a lower slope than the curves lying more to the left. The accumulation of a total dose for an iso-effect is not proportional to the increase in the number of fractions, but instead in the area above 5 fractions reaches a plateau. The survival curve of the one-time dose which I constructed in the shoulder area showed a strong agreement with the survival curve which was given by Withers and Hussey. (orig.) [de
Fractional Number Operator and Associated Fractional Diffusion Equations
Rguigui, Hafedh
2018-03-01
In this paper, we study the fractional number operator as an analog of the finite-dimensional fractional Laplacian. An important relation with the Ornstein-Uhlenbeck process is given. Using a semigroup approach, the solution of the Cauchy problem associated to the fractional number operator is presented. By means of the Mittag-Leffler function and the Laplace transform, we give the solution of the Caputo time fractional diffusion equation and Riemann-Liouville time fractional diffusion equation in infinite dimensions associated to the fractional number operator.
The bound fraction of young star clusters
Brinkmann, Nina; Banerjee, Sambaran; Motwani, Bhawna; Kroupa, Pavel
2017-04-01
Context. The residual gas within newly formed star clusters is expelled through stellar feedback on timescales ≲ 1 Myr. The subsequent expansion of the cluster results in an unbinding of a fraction of stars, before the remaining cluster members can re-virialize and form a surviving cluster. Aims: We investigate the bound fraction after gas expulsion as a function of initial cluster mass in stars Mecl and gauge the influence of primordial mass segregation, stellar evolution and the tidal field at solar distance. We also assess the impact of the star-formation efficiency ɛSFE and gas expulsion velocity vg. Methods: We perform N-body simulations using Sverre Aarseth's NBODY7 code, starting with compact clusters in their embedded phase and approximate the gas expulsion by means of an exponentially depleting external gravitational field. We follow the process of re-virialization through detailed monitoring of different Lagrange radii over several Myr, examining initial half-mass radii of 0.1 pc, 0.3 pc and 0.5 pc and Mecl usually ranging from 5 × 103M⊙ to 5 × 104M⊙. Results: The strong impact of the relation between the gas expulsion timescale and the crossing time means that clusters with the same initial core density can have very different bound fractions. The adopted ɛSFE = 0.33 in the cluster volume results in a distinct sensitivity to vg over a wide mass range, while a variation of ɛSFE can make the cluster robust to the rapidly decreasing external potential. We confirm that primordial mass segregation leads to a smaller bound fraction, its influence possibly decreasing with mass. Stellar evolution has a higher impact on lower mass clusters, but heating through dynamical friction could expand the cluster to a similar extent. The examined clusters expand well within their tidal radii and would survive gas expulsion even in a strong tidal field.
Role of radiotherapy fractionation in head and neck cancers (MARCH)
DEFF Research Database (Denmark)
Lacas, Benjamin; Bourhis, Jean; Overgaard, Jens
2017-01-01
BACKGROUND: The Meta-Analysis of Radiotherapy in squamous cell Carcinomas of Head and neck (MARCH) showed that altered fractionation radiotherapy is associated with improved overall and progression-free survival compared with conventional radiotherapy, with hyperfractionated radiotherapy showing...... the greatest benefit. This update aims to confirm and explain the superiority of hyperfractionated radiotherapy over other altered fractionation radiotherapy regimens and to assess the benefit of altered fractionation within the context of concomitant chemotherapy with the inclusion of new trials. METHODS......: For this updated meta-analysis, we searched bibliography databases, trials registries, and meeting proceedings for published or unpublished randomised trials done between Jan 1, 2009, and July 15, 2015, comparing primary or postoperative conventional fractionation radiotherapy versus altered fractionation...
Energy Technology Data Exchange (ETDEWEB)
Park, Shin Hyung; Kim, Jae Chul [Dept. of Radiation Oncology, Kyungpook National University School of Medicine, Daegu (Korea, Republic of)
2016-06-15
The standard radiation dose for patients with locally rectal cancer treated with preoperative chemoradiotherapy is 45–50 Gy in 25–28 fractions. We aimed to assess whether a difference exists within this dose fractionation range. A retrospective analysis was performed to compare three dose fractionation schedules. Patients received 50 Gy in 25 fractions (group A), 50.4 Gy in 28 fractions (group B), or 45 Gy in 25 fractions (group C) to the whole pelvis, as well as concurrent 5-fluorouracil. Radical resection was scheduled for 8 weeks after concurrent chemoradiotherapy. Between September 2010 and August 2013, 175 patients were treated with preoperative chemoradiotherapy at our institution. Among those patients, 154 were eligible for analysis (55, 50, and 49 patients in groups A, B, and C, respectively). After the median follow-up period of 29 months (range, 5 to 48 months), no differences were found between the 3 groups regarding pathologic complete remission rate, tumor regression grade, treatment-related toxicity, 2-year locoregional recurrence-free survival, distant metastasis-free survival, disease-free survival, or overall survival. The circumferential resection margin width was a prognostic factor for 2-year locoregional recurrence-free survival, whereas ypN category was associated with distant metastasis-free survival, disease-free survival, and overall survival. High tumor regression grading score was correlated with 2-year distant metastasis-free survival and disease-free survival in univariate analysis. Three different radiation dose fractionation schedules, within the dose range recommended by the National Comprehensive Cancer Network, had no impact on pathologic tumor regression and early clinical outcome for locally advanced rectal cancer.
Directory of Open Access Journals (Sweden)
N. Regnault
2011-12-01
Full Text Available Chern insulators are band insulators exhibiting a nonzero Hall conductance but preserving the lattice translational symmetry. We conclusively show that a partially filled Chern insulator at 1/3 filling exhibits a fractional quantum Hall effect and rule out charge-density-wave states that have not been ruled out by previous studies. By diagonalizing the Hubbard interaction in the flat-band limit of these insulators, we show the following: The system is incompressible and has a 3-fold degenerate ground state whose momenta can be computed by postulating an generalized Pauli principle with no more than 1 particle in 3 consecutive orbitals. The ground-state density is constant, and equal to 1/3 in momentum space. Excitations of the system are fractional-statistics particles whose total counting matches that of quasiholes in the Laughlin state based on the same generalized Pauli principle. The entanglement spectrum of the state has a clear entanglement gap which seems to remain finite in the thermodynamic limit. The levels below the gap exhibit counting identical to that of Laughlin 1/3 quasiholes. Both the 3 ground states and excited states exhibit spectral flow upon flux insertion. All the properties above disappear in the trivial state of the insulator—both the many-body energy gap and the entanglement gap close at the phase transition when the single-particle Hamiltonian goes from topologically nontrivial to topologically trivial. These facts clearly show that fractional many-body states are possible in topological insulators.
Fractional channel multichannel analyzer
Brackenbush, L.W.; Anderson, G.A.
1994-08-23
A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynchronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board. 9 figs.
Andreasen, Niels; Bjerregaard, Mads; Lund, Jonas; Olsen, Ove Bitsch; Rasmussen, Andreas Dalgas
2012-01-01
Projektet er bygget op omkring kritisk realisme, som er det gennemgående videnskabelige fundament til undersøgelsen af hvilke strukturelle grunde der er til finansiel ustabilitet i Danmark. Projektet går i dybden med Fractional Reserve Banking og incitamentsstrukturen i banksystemet. Vi bevæger os både på det makro- og mikroøkonomiske niveau i analysen. På makro niveau bruger vi den østrigske skole om konjunktur teori (The Positive Theory of the Cycle). På mikro niveau arbejder vi med princip...
Fractional Integral Inequalities via Hadamard’s Fractional Integral
Sudsutad, Weerawat; Ntouyas, Sotiris K.; Tariboon, Jessada
2014-01-01
We establish new fractional integral inequalities, via Hadamard’s fractional integral. Several new integral inequalities are obtained, including a Grüss type Hadamard fractional integral inequality, by using Young and weighted AM-GM inequalities. Many special cases are also discussed.
Fractional Integral Inequalities via Hadamard’s Fractional Integral
Directory of Open Access Journals (Sweden)
Weerawat Sudsutad
2014-01-01
Full Text Available We establish new fractional integral inequalities, via Hadamard’s fractional integral. Several new integral inequalities are obtained, including a Grüss type Hadamard fractional integral inequality, by using Young and weighted AM-GM inequalities. Many special cases are also discussed.
Fractional variational principles with delay
International Nuclear Information System (INIS)
Baleanu, Dumitru; Abdeljawad, Thabet Maaraba; Jarad, Fahd
2008-01-01
The fractional variational principles within Riemann-Liouville fractional derivatives in the presence of delay are analyzed. The corresponding Euler-Lagrange equations are obtained and one example is analyzed in detail
Advances in robust fractional control
Padula, Fabrizio
2015-01-01
This monograph presents design methodologies for (robust) fractional control systems. It shows the reader how to take advantage of the superior flexibility of fractional control systems compared with integer-order systems in achieving more challenging control requirements. There is a high degree of current interest in fractional systems and fractional control arising from both academia and industry and readers from both milieux are catered to in the text. Different design approaches having in common a trade-off between robustness and performance of the control system are considered explicitly. The text generalizes methodologies, techniques and theoretical results that have been successfully applied in classical (integer) control to the fractional case. The first part of Advances in Robust Fractional Control is the more industrially-oriented. It focuses on the design of fractional controllers for integer processes. In particular, it considers fractional-order proportional-integral-derivative controllers, becau...
International Nuclear Information System (INIS)
Turner, R.E.
1984-01-01
A search was made for fractional charges of the form Z plus two-thirds e, where Z is an integer. It was assumed that the charges exist in natural form bound with other fractional charges in neutral molecules. It was further assumed that these neutral molecules are present in air. Two concentration schemes were employed. One sample was derived from the waste gases from a xenon distillation plant. This assumes that high mass, low vapor pressure components of air are concentrated along with the xenon. The second sample involved ionizing air, allowing a brief recombination period, and then collecting residual ions on the surface of titanium discs. Both samples were analyzed at the University of Rochester in a system using a tandem Van de Graff to accelerate particles through an essentially electrostatic beam handling system. The detector system employed both a Time of Flight and an energy-sensitive gas ionization detector. In the most sensitive mode of analysis, a gas absorber was inserted in the beam path to block the intense background. The presence of an absorber limited the search to highly penetrating particles. Effectively, this limited the search to particles with low Z and masses greater than roughly fifty GeV. The final sensitivities attained were on the order of 1 x 10 -20 for the ionized air sample and 1 x 10 -21 for the gas sample. A discussion of the caveats that could reduce the actual level of sensitivity is included
Fractional Reserve in Banking System
Valkonen, Maria
2016-01-01
This thesis is aimed to provide understanding of the role of the fractional reserve in the mod-ern banking system worldwide and particularly in Finland. The fractional reserve banking is used worldwide, but the benefits of this system are very disputable. On the one hand, experts say that the fractional reserve is a necessary instrument for the normal business and profit making. On the other hand, sceptics openly criticize the fractional reserve system and blame it for fiat money (money n...
Hersh, Richard H.; Whiteman, James
1973-01-01
A High School course, General Studies Survival Curriculum, was designed to aid students in problem solving in a complex society. Areas of concern were psychology, consumer economics, environmental studies, law and society, religion and values, ethnic studies, applied aesthetics, creative studies, occupations and futurism. (JB)
Fractional Hopfield Neural Networks: Fractional Dynamic Associative Recurrent Neural Networks.
Pu, Yi-Fei; Yi, Zhang; Zhou, Ji-Liu
2017-10-01
This paper mainly discusses a novel conceptual framework: fractional Hopfield neural networks (FHNN). As is commonly known, fractional calculus has been incorporated into artificial neural networks, mainly because of its long-term memory and nonlocality. Some researchers have made interesting attempts at fractional neural networks and gained competitive advantages over integer-order neural networks. Therefore, it is naturally makes one ponder how to generalize the first-order Hopfield neural networks to the fractional-order ones, and how to implement FHNN by means of fractional calculus. We propose to introduce a novel mathematical method: fractional calculus to implement FHNN. First, we implement fractor in the form of an analog circuit. Second, we implement FHNN by utilizing fractor and the fractional steepest descent approach, construct its Lyapunov function, and further analyze its attractors. Third, we perform experiments to analyze the stability and convergence of FHNN, and further discuss its applications to the defense against chip cloning attacks for anticounterfeiting. The main contribution of our work is to propose FHNN in the form of an analog circuit by utilizing a fractor and the fractional steepest descent approach, construct its Lyapunov function, prove its Lyapunov stability, analyze its attractors, and apply FHNN to the defense against chip cloning attacks for anticounterfeiting. A significant advantage of FHNN is that its attractors essentially relate to the neuron's fractional order. FHNN possesses the fractional-order-stability and fractional-order-sensitivity characteristics.
Do Children Understand Fraction Addition?
Braithwaite, David W.; Tian, Jing; Siegler, Robert S.
2017-01-01
Many children fail to master fraction arithmetic even after years of instruction. A recent theory of fraction arithmetic (Braithwaite, Pyke, & Siegler, in press) hypothesized that this poor learning of fraction arithmetic procedures reflects poor conceptual understanding of them. To test this hypothesis, we performed three experiments…
Fractional dynamic calculus and fractional dynamic equations on time scales
Georgiev, Svetlin G
2018-01-01
Pedagogically organized, this monograph introduces fractional calculus and fractional dynamic equations on time scales in relation to mathematical physics applications and problems. Beginning with the definitions of forward and backward jump operators, the book builds from Stefan Hilger’s basic theories on time scales and examines recent developments within the field of fractional calculus and fractional equations. Useful tools are provided for solving differential and integral equations as well as various problems involving special functions of mathematical physics and their extensions and generalizations in one and more variables. Much discussion is devoted to Riemann-Liouville fractional dynamic equations and Caputo fractional dynamic equations. Intended for use in the field and designed for students without an extensive mathematical background, this book is suitable for graduate courses and researchers looking for an introduction to fractional dynamic calculus and equations on time scales. .
Membrane Assisted Enzyme Fractionation
DEFF Research Database (Denmark)
Yuan, Linfeng
. In this thesis, separations using crossflow elecro-membrane filtration (EMF) of amino acids, bovine serum albumin (BSA) and industrial enzymes from Novozymes were performed. The main objective of this study was to investigate the technological feasibility of EMF in the application of industrial enzyme...... fractionation, such as removal of a side activity from the main enzyme activity. As a proof-of-concept, amino acids were used as model solution to test the feasibility of EMF in the application of amphoteric molecule separation. A single amino acid was used to illustrate the effect of an electric field...... on the separation performance were very small in the investigated range. The mass transport of each enzyme can be well explained by the Extended-Nernst-Planck equation. Better separation was observed at lower feed concentration, higher solution pH in the investigated range and with a polysulfone (PS) MF membrane...
Thermochemical transformations of anthracite fractions
Energy Technology Data Exchange (ETDEWEB)
Belkina, T.V.; Privalov, V.E.; Stepanenko, atM.A.
1979-08-01
Research on the nature of thermochemical transformations of anthracite fractions and the possibility of increasing their activity and identifying conditions for their use in the electrode pitch process is described. From research done on different anthracite fractions processed at varying temperatures it was concluded that accumulations of condensates from heating anthracite fractions occur significantly slower in comparison with pitch. As a result the electrode pitch process is prolonged. Thermal treatment of an anthracite fraction causes the formation and accumulation of condensates and promotes thermochemical transformations. Lastly, the use of thermally treated anthracite fractions apparently intensifies the electrode pitch process and improves its quality. (16 refs.) (In Russian)
Aircraft Survivability. Spring 2011
2011-01-01
panel exhibiting telltale signs and critical fragments were identified and collected. The weapon employed against the aircraft was correctly assessed...701C engines (for FCR- equipped Apache Longbows), and a fully integrated cockpit. In addition, the aircraft received improved survivability...sustained analytical contributions to improve the survivability and effectiveness of US military aircraft and weapon systems. These contributions
Toward lattice fractional vector calculus
Tarasov, Vasily E.
2014-09-01
An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity.
Energy Technology Data Exchange (ETDEWEB)
Wiggenraad, R.; Verbeek-de Kanter, A.; Mast, M. [Radiotherapy Centre West, The Hague (Netherlands); Molenaar, R. [Diaconessenhuis, Leiden (Netherlands). Dept. of Neurology; Lycklama a Nijeholt, G. [Medical Centre Haagladen, The Hague (Netherlands). Dept. of Radiology; Vecht, C. [Medical Centre Haagladen, The Hague (Netherlands). Dept. of Neurology; Struikmans, H. [Radiotherapy Centre West, The Hague (Netherlands); Leiden Univ. Medical Centre (Netherlands). Dept. of Radiotherapy; Kal, H.B.
2012-08-15
Purpose: The 1-year local control rates after single-fraction stereotactic radiotherapy (SRT) for brain metastases > 3 cm diameter are less than 70%, but with fractionated SRT (FSRT) higher local control rates have been reported. The purpose of this study was to compare our treatment results with SRT and FSRT for large brain metastases. Materials and methods: In two consecutive periods, 41 patients with 46 brain metastases received SRT with 1 fraction of 15 Gy, while 51 patients with 65 brain metastases received FSRT with 3 fractions of 8 Gy. We included patients with brain metastases with a planning target volume of > 13 cm{sup 3} or metastases in the brainstem. Results: The minimum follow-up of patients still alive was 22 months. Comparing 1 fraction of 15 Gy with 3 fractions of 8 Gy, the 1-year rates of freedom from any local progression (54% and 61%, p = 0.93) and pseudo progression (85% and 75%, p = 0.25) were not significantly different. Overall survival rates were also not different. Conclusion: The 1-year local progression and pseudo progression rates after 1 fraction of 15 Gy or 3 fractions of 8 Gy for large brain metastases and metastases in the brainstem are similar. For better local control rates, FSRT schemes with a higher biological equivalent dose may be necessary. (orig.)
Misonidazole in fractionated radiotherapy: are many small fractions best
International Nuclear Information System (INIS)
Denekamp, J.; McNally, N.J.; Fowler, J.F.; Joiner, M.C.
1980-01-01
The largest sensitizing effect is always demonstrated with six fractions, each given with 2 g/m 2 of misonidazole. In the absence of reoxygenation a sensitizer enhancement ratio of 1.7 is predicted, but this falls to 1.1-1.2 if extensive reoxygenation occurs. Less sensitization is observed with 30 fractions, each with 0.4 g/m 2 of drug. However, for clinical use, the important question is which treatment kills the maximum number of tumour cells. Many of the simulations predict a marked disadvantage of reducing the fraction number for X rays alone. The circumstances in which this disadvantage is offset by the large Sensitizer enhancement ratio values with a six-fraction schedule are few. The model calculations suggest that many small fractions, each with a low drug dose, are safest unless the clinician has some prior knowledge that a change in fraction number is not disadvantageous. (author)
Network Survivability Performance
1993-11-01
Daneshmand S. Makris J. Sosnosky R. Doverspike H. Mar E. Turner F. Ellefson J. McDonough R. Waller W. Grover M. Mostrel G. Williams H. Holton S. Nadkarni J...restoration starts (1-U), Su the fraction of x unservable after failure has happened znd before restoration starts (U), Sr the fraction of x that is...restored at ti, to the time the failure occurs, tr the duration required until fraction Sa+ Sr of x is restored, and tR the duration required until all of x
Fractional variational calculus in terms of Riesz fractional derivatives
International Nuclear Information System (INIS)
Agrawal, O P
2007-01-01
This paper presents extensions of traditional calculus of variations for systems containing Riesz fractional derivatives (RFDs). Specifically, we present generalized Euler-Lagrange equations and the transversality conditions for fractional variational problems (FVPs) defined in terms of RFDs. We consider two problems, a simple FVP and an FVP of Lagrange. Results of the first problem are extended to problems containing multiple fractional derivatives, functions and parameters, and to unspecified boundary conditions. For the second problem, we present Lagrange-type multiplier rules. For both problems, we develop the Euler-Lagrange-type necessary conditions which must be satisfied for the given functional to be extremum. Problems are considered to demonstrate applications of the formulations. Explicitly, we introduce fractional momenta, fractional Hamiltonian, fractional Hamilton equations of motion, fractional field theory and fractional optimal control. The formulations presented and the resulting equations are similar to the formulations for FVPs given in Agrawal (2002 J. Math. Anal. Appl. 272 368, 2006 J. Phys. A: Math. Gen. 39 10375) and to those that appear in the field of classical calculus of variations. These formulations are simple and can be extended to other problems in the field of fractional calculus of variations
Dynamical fractional chaotic inflation
Harigaya, Keisuke; Ibe, Masahiro; Schmitz, Kai; Yanagida, Tsutomu T.
2014-12-01
Chaotic inflation based on a simple monomial scalar potential, V (ϕ )∝ϕp, is an attractive large-field model of inflation capable of generating a sizable tensor-to-scalar ratio r . Therefore, assuming that future cosmic microwave background observations will confirm the large r value reported by BICEP2, it is important to determine what kind of dynamical mechanism could possibly endow the inflaton field with such a simple effective potential. In this paper, we answer this question in the context of field theory, i.e. in the framework of dynamical chaotic inflation, where strongly interacting supersymmetric gauge dynamics around the scale of grand unification dynamically generate a fractional power-law potential via the quantum effect of dimensional transmutation. In constructing explicit models, we significantly extend our previous work, as we now consider a large variety of possible underlying gauge dynamics and relax our conditions on the field content of the model. This allows us to realize almost arbitrary rational values for the power p in the inflaton potential. The present paper may hence be regarded as a first step toward a more complete theory of dynamical chaotic inflation.
International Nuclear Information System (INIS)
Storb, R.; Raff, R.F.; Graham, T.; Appelbaum, F.R.; Deeg, H.J.; Schuening, F.G.; Shulman, H.; Pepe, M.
1993-01-01
The authors explored in dogs the marrow toxicity of single dose total body irradiation delivered from two opposing 60 Co sources at a rate of 10 cGy/min and compared results to those seen with total body irradiation administered in 100 cGy fractions with minimum interfraction intervals of 6 hr. Dogs were not given marrow transplants. They found that 200 cGy single dose total body irradiation was sublethal, with 12 of 13 dogs showing hematopoietic recovery and survival. Seven of 21 dogs given 300 cGy single dose total body irradiation survived compared to 6 of 10 dogs given 300 cGy fractionated total body irradiation. One of 28 dogs given 400 cGy single dose total body irradiation survived compared to none of six given fractionated radiation. With granulocyte colony stimulating factor (GCSF) administered from day 0-21 after 400 cGy total body irradiation, most dogs survived with hematological recovery. Because of the almost uniform success with GCSF after 400 cGy single dose total body irradiation, a study of GCSF after 400 cGy fractionated total body irradiation was deemed not to be informative and, thus, not carried out. Additional comparisons between single dose and fractionated total body irradiation were carried out with GCSF administered after 500 and 600 cGy of total body irradiation. As with lower doses of total body irradiation, no significant survival differences were seen between the two modes of total body irradiation, and only 3 of 26 dogs studied survived with complete hematological recovery. Overall, therefore, survival among dogs given single dose total body irradiation was not different from that of dogs given fractionated total body irradiation (p = .67). Similarly, the slopes of the postirradiation declines of granulocyte and platelet counts and the rates of their recovery in surviving dogs given equal total doses of single versus fractionated total body irradiation were indistinguishable. 24 refs., 3 figs., 2 tabs
Accessible solitons of fractional dimension
Energy Technology Data Exchange (ETDEWEB)
Zhong, Wei-Ping, E-mail: zhongwp6@126.com [Department of Electronic and Information Engineering, Shunde Polytechnic, Guangdong Province, Shunde 528300 (China); Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Belić, Milivoj [Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Zhang, Yiqi [Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China)
2016-05-15
We demonstrate that accessible solitons described by an extended Schrödinger equation with the Laplacian of fractional dimension can exist in strongly nonlocal nonlinear media. The soliton solutions of the model are constructed by two special functions, the associated Legendre polynomials and the Laguerre polynomials in the fraction-dimensional space. Our results show that these fractional accessible solitons form a soliton family which includes crescent solitons, and asymmetric single-layer and multi-layer necklace solitons. -- Highlights: •Analytic solutions of a fractional Schrödinger equation are obtained. •The solutions are produced by means of self-similar method applied to the fractional Schrödinger equation with parabolic potential. •The fractional accessible solitons form crescent, asymmetric single-layer and multilayer necklace profiles. •The model applies to the propagation of optical pulses in strongly nonlocal nonlinear media.
Fractional Calculus and Shannon Wavelet
Directory of Open Access Journals (Sweden)
Carlo Cattani
2012-01-01
Full Text Available An explicit analytical formula for the any order fractional derivative of Shannon wavelet is given as wavelet series based on connection coefficients. So that for any 2(ℝ function, reconstructed by Shannon wavelets, we can easily define its fractional derivative. The approximation error is explicitly computed, and the wavelet series is compared with Grünwald fractional derivative by focusing on the many advantages of the wavelet method, in terms of rate of convergence.
DEFF Research Database (Denmark)
Rhodes, Andrew; Evans, Laura E; Alhazzani, Waleed
2017-01-01
OBJECTIVE: To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012". DESIGN: A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meeting...
Fractional delayed damped Mathieu equation
Mesbahi, Afshin; Haeri, Mohammad; Nazari, Morad; Butcher, Eric A.
2015-03-01
This paper investigates the dynamical behaviour of the fractional delayed damped Mathieu equation. This system includes three different phenomena (fractional order, time delay, parametric resonance). The method of harmonic balance is employed to achieve approximate expressions for the transition curves in the parameter plane. The n = 0 and n = 1 transition curves (both lower and higher order approximations) are obtained. The dependencies of these curves on the system parameters and fractional orders are determined. Previous results for the transition curves reported for the damped Mathieu equation, delayed second-order oscillator, and fractional Mathieu equation are confirmed as special cases of the results for the current system.
A track-event theory of cell survival
Energy Technology Data Exchange (ETDEWEB)
Besserer, Juergen; Schneider, Uwe [Zuerich Univ. (Switzerland). Inst. of Physics; Radiotherapy Hirslanden, Zuerich (Switzerland)
2015-09-01
When fractionation schemes for hypofractionation and stereotactic body radiotherapy are considered, a reliable cell survival model at high dose is needed for calculating doses of similar biological effectiveness. In this work a simple model for cell survival which is valid also at high dose is developed from Poisson statistics. An event is defined by two double strand breaks (DSB) on the same or different chromosomes. An event is always lethal due to direct lethal damage or lethal binary misrepair by the formation of chromosome aberrations. Two different mechanisms can produce events: one-track events (OTE) or two-track-events (TTE). The target for an OTE is always a lethal event, the target for an TTE is one DSB. At least two TTEs on the same or different chromosomes are necessary to produce an event. Both, the OTE and the TTE are statistically independent. From the stochastic nature of cell kill which is described by the Poisson distribution the cell survival probability was derived. It was shown that a solution based on Poisson statistics exists for cell survival. It exhibits exponential cell survival at high dose and a finite gradient of cell survival at vanishing dose, which is in agreement with experimental cell studies. The model fits the experimental data nearly as well as the three-parameter formula of Hug-Kellerer and is only based on two free parameters. It is shown that the LQ formalism is an approximation of the model derived in this work. It could be also shown that the derived model predicts a fractionated cell survival experiment better than the LQ-model. It was shown that cell survival can be described with a simple analytical formula on the basis of Poisson statistics. This solution represents in the limit of large dose the typical exponential behavior and predicts cell survival after fractionated dose application better than the LQ-model.
COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS
Energy Technology Data Exchange (ETDEWEB)
S.O. Bader
1999-10-18
The purpose of this design analysis is to specify and document the total and respirable fractions for radioactive materials that are released from an accident event at the Monitored Geologic Repository (MGR) involving commercial spent nuclear fuel (CSNF) in a dry environment. The total and respirable release fractions will be used to support the preclosure licensing basis for the MGR. The total release fraction is defined as the fraction of total CSNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. The radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses. This subset of the total release fraction is referred to as the respirable release fraction. Potential accidents may involve waste forms that are characterized as either bare (unconfined) fuel assemblies or confined fuel assemblies. The confined CSNF assemblies at the MGR are contained in shipping casks, canisters, or disposal containers (waste packages). In contrast to the bare fuel assemblies, the container that confines the fuel assemblies has the potential of providing an additional barrier for diminishing the total release fraction should the fuel rod cladding breach during an accident. However, this analysis will not take credit for this additional bamer and will establish only the total release fractions for bare unconfined CSNF assemblies, which may however be
The response of mouse skin and lung to fractionated x-rays
International Nuclear Information System (INIS)
Field, S.B.; Hornsey, S.
1975-01-01
The relationship between total dose and number of fractions has been investigated for damage to lung and skin in mice. Single doses and various numbers of fractions have been given and the results are analysed in two ways: (i) by comparing the fractionated treatment with a single dose. With this approach, and assuming that the observed damage to lung and skin is the result of cell killing, it is estimated that the ratio of initial to final slope of the cell survival curve is about 7:1; (ii) by measuring the additional dose required when the number of fractions is doubled. These results are roughly fitted by a single-hit times multitarget survival-curve model, with the ratio of slopes about 3:1. It is concluded from this discrepancy that the two-component model is an inadequate description of the survival curve for the cells of either skin or lung. (author)
Financial Planning with Fractional Goals
M.H. Goedhart; J. Spronk (Jaap)
1995-01-01
textabstractWhen solving financial planning problems with multiple goals by means of multiple objective programming, the presence of fractional goals leads to technical difficulties. In this paper we present a straightforward interactive approach for solving such linear fractional programs with
Deterministic ratchets for suspension fractionation
Kulrattanarak, T.
2010-01-01
Driven by the current insights in sustainability and technological development in biorefining natural renewable resources, the food industry has taken an interest in fractionation of agrofood materials, like milk and cereal crops. The purpose of fractionation is to split the raw material in
Rational Exponentials and Continued Fractions
Denny, J. K.
2012-01-01
Using continued fraction expansions, we can approximate constants, such as pi and e, using an appropriate integer n raised to the power x[superscript 1/x], x a suitable rational. We review continued fractions and give an algorithm for producing these approximations.
Fractional random walk lattice dynamics
Michelitsch, T. M.; Collet, B. A.; Riascos, A. P.; Nowakowski, A. F.; Nicolleau, F. C. G. A.
2017-02-01
We analyze time-discrete and time-continuous ‘fractional’ random walks on undirected regular networks with special focus on cubic periodic lattices in n = 1, 2, 3,.. dimensions. The fractional random walk dynamics is governed by a master equation involving fractional powers of Laplacian matrices {{L}\\fracα{2}}} where α =2 recovers the normal walk. First we demonstrate that the interval 0expressions for the transition matrix of the fractional random walk and closely related the average return probabilities. We further obtain the fundamental matrix {{Z}(α )} , and the mean relaxation time (Kemeny constant) for the fractional random walk. The representation for the fundamental matrix {{Z}(α )} relates fractional random walks with normal random walks. We show that the matrix elements of the transition matrix of the fractional random walk exihibit for large cubic n-dimensional lattices a power law decay of an n-dimensional infinite space Riesz fractional derivative type indicating emergence of Lévy flights. As a further footprint of Lévy flights in the n-dimensional space, the transition matrix and return probabilities of the fractional random walk are dominated for large times t by slowly relaxing long-wave modes leading to a characteristic {{t}-\\frac{n{α}} -decay. It can be concluded that, due to long range moves of fractional random walk, a small world property is emerging increasing the efficiency to explore the lattice when instead of a normal random walk a fractional random walk is chosen.
Permutation entropy of fractional Brownian motion and fractional Gaussian noise
International Nuclear Information System (INIS)
Zunino, L.; Perez, D.G.; Martin, M.T.; Garavaglia, M.; Plastino, A.; Rosso, O.A.
2008-01-01
We have worked out theoretical curves for the permutation entropy of the fractional Brownian motion and fractional Gaussian noise by using the Bandt and Shiha [C. Bandt, F. Shiha, J. Time Ser. Anal. 28 (2007) 646] theoretical predictions for their corresponding relative frequencies. Comparisons with numerical simulations show an excellent agreement. Furthermore, the entropy-gap in the transition between these processes, observed previously via numerical results, has been here theoretically validated. Also, we have analyzed the behaviour of the permutation entropy of the fractional Gaussian noise for different time delays
Toxicity, Growth And Survival Of Clarias Gariepinus Juveniles ...
African Journals Online (AJOL)
Toxicity, Growth And Survival Of Clarias Gariepinus Juveniles Exposed To Different Concentrations Of Crude Oil Fractions-Polluted Water. ... soluble organic nitrogen and colloidal organic nitrogen in addition to soluble and adsorbed ammonia in the aquaria water and sediments were analyzed using standard methods.
Toward lattice fractional vector calculus
International Nuclear Information System (INIS)
Tarasov, Vasily E
2014-01-01
An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity. (papers)
Ferroelectric Fractional-Order Capacitors
Agambayev, Agamyrat
2017-07-25
Poly(vinylidene fluoride)-based polymers and their blends are used to fabricate electrostatic fractional-order capacitors. This simple but effective method allows us to precisely tune the constant phase angle of the resulting fractional-order capacitor by changing the blend composition. Additionally, we have derived an empirical relation between the ratio of the blend constituents and the constant phase angle to facilitate the design of a fractional order capacitor with a desired constant phase angle. The structural composition of the fabricated blends is investigated using Fourier transform infrared spectroscopy and X-ray diffraction techniques.
On Generalized Fractional Differentiator Signals
Directory of Open Access Journals (Sweden)
Hamid A. Jalab
2013-01-01
Full Text Available By employing the generalized fractional differential operator, we introduce a system of fractional order derivative for a uniformly sampled polynomial signal. The calculation of the bring in signal depends on the additive combination of the weighted bring-in of N cascaded digital differentiators. The weights are imposed in a closed formula containing the Stirling numbers of the first kind. The approach taken in this work is to consider that signal function in terms of Newton series. The convergence of the system to a fractional time differentiator is discussed.
Prabhakar-like fractional viscoelasticity
Giusti, Andrea; Colombaro, Ivano
2018-03-01
The aim of this paper is to present a linear viscoelastic model based on Prabhakar fractional operators. In particular, we propose a modification of the classical fractional Maxwell model, in which we replace the Caputo derivative with the Prabhakar one. Furthermore, we also discuss how to recover a formal equivalence between the new model and the known classical models of linear viscoelasticity by means of a suitable choice of the parameters in the Prabhakar derivative. Moreover, we also underline an interesting connection between the theory of Prabhakar fractional integrals and the recently introduced Caputo-Fabrizio differential operator.
Multiple Daily Fractionated RT for Malignant Glioma
Energy Technology Data Exchange (ETDEWEB)
Yang, Kang Mo; Chang, Hye Sook; Ahn, Seoung Do; Choi, Eun Kyung [Ulsan University College of Medicine, Seoul (Korea, Republic of)
1994-06-15
Since Jan. 1992, authors have conducted a pilot study to treat malignant glioma with multiple daily fractionated (MDF) radiation therapy and this paper presents the outcome compared MDF to conventional fractionated (CF) radiation therapy. Between Sep. 1989 and Jan. 1993, forty-three patients with high grade glioma of brain except brain stem glioma were treated: nineteen patients were treated with CF radiation therapy and 24 patients were treated with MDF radiation therapy. In CF radiation therapy, total dose was 6300cHy/35fx in 7 weeks, which 5040cGy was delivered to the initial target volume and 1260cGy to reduced target volume. And in MDF radiation therapy, total dose was 6400cGy/40fx in 4 weeks, which 3200cGy was delivered to the initial target volume as 160cGy 2 times daily 6hr apart. All patients had histologically confirmed anaplastic astrocytoma (AA) of glioblastoma multiforme(GBM) with stereotactic biopsy or craniotomy for subtotal or gross tumor resection. The rage of follow-up was 7 months to 4 years with a median follow-up of 9 months. The Median survival from surgery was 9 months for all patients. The median survival was 9 months and 10 months for MDF group and CF group and 10 months and 9.5 months for glioblastoma multiforme and anaplastic astrocytoma, respectively. In 36 patients with follow-up CT scan or MRI scan, disease status was evaluated according to treatment group. Four patients (GBM:3, AA:1) of 21 patients in MDF group, were alive with no evidence of disease, while none of patient was alive with no evidence of disease in CF group. The progression of disease had occurred in 20 patients, 11 patients and 9 patients in MDF group and CF group, respectively. All of these patients showed in-field progression of disease. Four of 11 patients (27%) in MDF group showed the new lesion outside of the treatment field, while 5 of 9 patients(56%) in CF group. In our study the prognosis was not influenced by age, KPS, grade, extent of surgery and different
DEFF Research Database (Denmark)
Acheampong, George; Narteh, Bedman; Rand, John
2017-01-01
of the SCPFs in Ghana. Distribution ties are associated with negative survival chances and this is not even reversed if the human capital of the owner increases although managers with higher human capital and higher distribution ties experience positive effects. Industry ties are associated with positive ties...
Aldrich, Richard
2010-01-01
This article provides a brief overview of current approaches to education and concludes that none of these is sufficient to meet the challenges that now face the human race. It argues instead for a new concept of education for survival. (Contains 1 note.)
Multinationals and plant survival
DEFF Research Database (Denmark)
Bandick, Roger
2010-01-01
-parametric estimates show that domestic MNE plants are more likely to exit the market than other plants, also when controlling for plant-specific differences. Finally, foreign presence in the market seems to have had a negative impact on the survival rate of plants in non-exporting non- MNEs, but not to have affected...
DEFF Research Database (Denmark)
Bille, Trine; Jensen, Søren
2017-01-01
The literature of cultural economics generally finds that an artistic education has no significant impact on artists’ income and careers in the arts. In our research, we have readdressed this question by looking at the artists’ survival in the arts occupations. The results show that an artistic...... education has a significant impact on artists’ careers in the arts and we find important industry differences....
Survivability via Control Objectives
Energy Technology Data Exchange (ETDEWEB)
CAMPBELL,PHILIP L.
2000-08-11
Control objectives open an additional front in the survivability battle. A given set of control objectives is valuable if it represents good practices, it is complete (it covers all the necessary areas), and it is auditable. CobiT and BS 7799 are two examples of control objective sets.
Flexible survival regression modelling
DEFF Research Database (Denmark)
Cortese, Giuliana; Scheike, Thomas H; Martinussen, Torben
2009-01-01
Regression analysis of survival data, and more generally event history data, is typically based on Cox's regression model. We here review some recent methodology, focusing on the limitations of Cox's regression model. The key limitation is that the model is not well suited to represent time-varyi...
Allen, James E., Jr.
In this address, James E. Allen, Jr., Assistant Secretary for Education and U.S. Commissioner of Education, discusses the relationship of education to the problem of ecological destruction. He states that the solutions to the problems of air, water, and soil pollution may be found in redirected education. This "education for survival" can serve to…
Australia's Next Top Fraction Model
Gould, Peter
2013-01-01
Peter Gould suggests Australia's next top fraction model should be a linear model rather than an area model. He provides a convincing argument and gives examples of ways to introduce a linear model in primary classrooms.
Physcicists rewarded for 'fractional electrons'
Ball, P
1998-01-01
The 1998 Nobel prize for physics has been awarded to Horst Stormer, Daniel Tsui and Robert Laughlin.Stormer and Tsui were the first to observe the fractional quantum Hall effect and Laughlin provided the theory shortly afterwards (1 page).
Fractionated Spacecraft Architectures Seeding Study
National Research Council Canada - National Science Library
Mathieu, Charlotte; Weigel, Annalisa
2006-01-01
The report introduces the concept of spacecraft fractionation, which transforms a traditional monolithic spacecraft into a network of elements where a free-flying payload module is supported by nearby...
Ultracentrifugation for ultrafine nanodiamond fractionation
Koniakhin, S. V.; Besedina, N. A.; Kirilenko, D. A.; Shvidchenko, A. V.; Eidelman, E. D.
2018-01-01
In this paper we propose a method for ultrafine fractionation of nanodiamonds using the differential centrifugation in the fields up to 215000g. The developed protocols yield 4-6 nm fraction giving main contribution to the light scattering intensity. The desired 4-6 nm fraction can be obtained from various types of initial nanodiamonds: three types of detonation nanodiamonds differing in purifying methods, laser synthesis nanodiamonds and nanodiamonds made by milling. The characterization of the obtained hydrosols was conducted with Dynamic Light Scattering, Zeta potential measurements, powder XRD and TEM. According to powder XRD and TEM data ultracentrifugation also leads to a further fractionation of the primary diamond nanocrystallites in the hydrosols from 4 to 2 nm.
Commercial SNF Accident Release Fractions
Energy Technology Data Exchange (ETDEWEB)
J. Schulz
2004-11-05
The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M&O 1999). In contrast to bare unconfined fuel assemblies, the
Commercial SNF Accident Release Fractions
International Nuclear Information System (INIS)
Schulz, J.
2004-01-01
The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M andO 1999). In contrast to bare unconfined fuel assemblies, the
Fractional Reserve Banking: Some Quibbles
Bagus, Philipp; Howden, David
2010-01-01
We explore several unaddressed issues in George Selgin’s (1988) claim that the best monetary system to maintain monetary equilibrium is a fractional reserve free banking one. The claim that adverse clearing balances would limit credit expansion in a fractional reserve free banking system is more troublesome than previously reckoned. Both lengthened clearing periods and interbank agreements render credit expansion unrestrained. “The theory of free banking” confuses increases in money held with...
Fractional diffusion in inhomogeneous media
Energy Technology Data Exchange (ETDEWEB)
Chechkin, A V [Institute for Theoretical Physics, National Science Center ' Kharkov Institute of Physics and Technology' , Akademicheskaya St. 1, Kharkov 61108 (Ukraine); Gorenflo, R [Department of Mathematics and Informatics, Free University of Berlin, Arnimallee 3, D-14195 Berlin, Dahlem (Germany); Sokolov, I M [Institute for Physics, Humboldt University of Berlin, Newtonstrasse 15, D-12489 Berlin (Germany)
2005-10-21
Starting from the continuous time random walk (CTRW) scheme with the space-dependent waiting-time probability density function (PDF) we obtain the time-fractional diffusion equation with varying in space fractional order of time derivative. As an example, we study the evolution of a composite system consisting of two separate regions with different subdiffusion exponents and demonstrate the effects of non-trivial drift and subdiffusion whose laws are changed in the course of time. (letter to the editor)
Fractional Charge Definitions and Conditions
Energy Technology Data Exchange (ETDEWEB)
Goldhaber, A.S.
2004-06-04
Fractional charge is known through theoretical and experimental discoveries of isolable objects carrying fractions of familiar charge units--electric charge Q, spin S, and the difference of baryon and lepton numbers B-L. With a few simple assumptions all these effects may be described using a generalized version of charge renormalization for locally conserved charges, in which medium correlations yield familiar adiabatic, continuous renormalization, or sometimes nonadiabatic, discrete renormalization. Fractional charges may be carried by fundamental particles or fundamental solitons. Either picture works for the simplest fractional-quantum-Hall-effect quasiholes, though the particle description is far more general. The only known fundamental solitons in three or fewer space dimensions d are the kink (d = 1), the vortex (d = 2), and the magnetic monopole (d = 3). Further, for a charge not intrinsically coupled to the topological charge of a soliton, only the kink and the monopole may carry fractional values. The same reasoning enforces fractional values of B-L for electrically charged elementary particles.
Conformable Fractional Bessel Equation and Bessel Functions
Gökdoğan, Ahmet; Ünal, Emrah; Çelik, Ercan
2015-01-01
In this work, we study the fractional power series solutions around regular singular point x=0 of conformable fractional Bessel differential equation and fractional Bessel functions. Then, we compare fractional solutions with ordinary solutions. In addition, we present certain property of fractional Bessel functions.
Discrete fractional solutions of a Legendre equation
Yılmazer, Resat
2018-01-01
One of the most popular research interests of science and engineering is the fractional calculus theory in recent times. Discrete fractional calculus has also an important position in fractional calculus. In this work, we acquire new discrete fractional solutions of the homogeneous and non homogeneous Legendre differential equation by using discrete fractional nabla operator.
Survival after blood transfusion
DEFF Research Database (Denmark)
Kamper-Jørgensen, Mads; Ahlgren, Martin; Rostgaard, Klaus
2008-01-01
of transfusion recipients in Denmark and Sweden followed for up to 20 years after their first blood transfusion. Main outcome measure was all-cause mortality. RESULTS: A total of 1,118,261 transfusion recipients were identified, of whom 62.0 percent were aged 65 years or older at the time of their first...... the SMR remained significantly 1.3-fold increased. CONCLUSION: The survival and relative mortality patterns among blood transfusion recipients were characterized with unprecedented detail and precision. Our results are relevant to assessments of the consequences of possible transfusion-transmitted disease......BACKGROUND: Long-term survival of transfusion recipients has rarely been studied. This study examines short- and long-term mortality among transfusion recipients and reports these as absolute rates and rates relative to the general population. STUDY DESIGN AND METHODS: Population-based cohort study...
Survival analysis models and applications
Liu, Xian
2012-01-01
Survival analysis concerns sequential occurrences of events governed by probabilistic laws. Recent decades have witnessed many applications of survival analysis in various disciplines. This book introduces both classic survival models and theories along with newly developed techniques. Readers will learn how to perform analysis of survival data by following numerous empirical illustrations in SAS. Survival Analysis: Models and Applications: Presents basic techniques before leading onto some of the most advanced topics in survival analysis.Assumes only a minimal knowledge of SAS whilst enablin
Delayed coker fractionator advanced control
Energy Technology Data Exchange (ETDEWEB)
Jaisinghani, R.; Minter, B. (ABB SIMCON Inc., Houston, TX (United States)); Tica, A.; Puglesi, A.; Ojeda, R. (Yacimentos Petroliferos Fiscales, Mendoza (Argentina))
1993-08-01
In a delayed coking process, as coke drum switches are made, rapid changes occur in both the fractionator feed rate and composition. With conventional control, it is not unusual to see long transient behavior of large swings in both quality and flowrates of coker gas oils. This can extract a heavy economic toll, not only in coker operation, but in the operation of downstream units as the upset is propagated. An advanced process control application (APC) was recently implemented on the coker fractionator at the Yacimentos Petroliferos Fiscales (YPF), Lujan de Cuyo Refinery, in Mendoza, Argentina. This coker fractionator control design was unique as it handled two different operating objectives: control of product qualities via tower temperature profile during normal operation and control of gas oil product flow ratio during drum switch. This combination of control objectives in one multivariable predictive control program was achieved by including special logic to decouple the individual tuning requirements. Also, additional logic was included to unambiguously detect and identify drum switch and drum steam out as discrete events within 30 seconds of their actual occurrence. These discrete events were then used as disturbance variables to minimize fractionator transient behavior. As a performance measure, the overhead temperature was controlled within 2 C to 2.5 C of its target, gas oil flows were stabilized during drum switches and steam generation via pump around was maximized. Overall, implementing advanced control for the delayed coker fractionator resulted in substantial benefits from product quality control, product flow control and minimized energy consumption.
Pimenta, Lúcia Pinheiro Santos; Garcia, Giani Martins; Gonçalves, Samuel Geraldo do Vale; Dionísio, Bárbara Lana; Braga, Erika Martins; Mosqueira, Vanessa Carla Furtado
2014-01-01
Annona crassiflora and Annonaceae plants are known to be used to treat malaria by traditional healers. In this work, the antimalarial efficacy of different fractions of A. crassiflora, particularly acetogenin, alkaloids and flavonoid-rich fractions, was determined in vivo using Plasmodium berghei-infected mice model and toxicity was accessed by brine shrimp assay. The A. crassiflora fractions were administered at doses of 12.5 mg/kg/day in a 4-day test protocol. The results showed that some fractions from woods were rich in acetogenins, alkaloids and terpenes, and other fractions from leaves were rich in alkaloids and flavonoids. The parasitaemia was significantly (p < 0.05, p < 0.001) reduced (57-75%) with flavonoid and alkaloid-rich leaf fractions, which also increased mean survival time of mice after treatment. Our results confirm the usage of this plant in folk medicine as an antimalarial remedy.
Implication of fractionated dose exposures in therapeutic gain
International Nuclear Information System (INIS)
Kim, Hye-Jin; Lee, Min-Ho; Kim, Eun-Hee
2016-01-01
Radiation therapy pursues killing tumor cells while sparing normal cells from the radiation exposure. Stereotactic radiosurgery (SRS) is a cancer treatment modality that delivers a high dose in a single operation. This high-dose single operation shortens the treatment course, but can increase the risk of normal cell damage. Normal cell damage can be reduced by employing multi-directional exposures for an increasing number of isocenters. In this study, we investigated whether therapeutic benefits would be expected by employing new dose fractionation patterns at a high-dose single operation. The conventional single-dose operation in brain tumor radiosurgery is performed by delivering fractionated uniform doses. According to Figs. 2 and 3, the conventional radiosurgery might have obtained some therapeutic benefit by employing the fractionated uniform-dose exposures instead of a single-dose exposure. We suggest that further therapeutic gain be expected by employing the fractionated radiation exposures in an increasing dose pattern. Until ensuring our suggestion, the significance in gain of cell surviving should be verified for all three dose patterns with both normal and tumor cells. The investigation whether normal and tumor cells show the same responses to the fractionated dose exposures at lower and higher than 15 Gy of total dose is also reserved for future work
Semi-infinite fractional programming
Verma, Ram U
2017-01-01
This book presents a smooth and unified transitional framework from generalised fractional programming, with a finite number of variables and a finite number of constraints, to semi-infinite fractional programming, where a number of variables are finite but with infinite constraints. It focuses on empowering graduate students, faculty and other research enthusiasts to pursue more accelerated research advances with significant interdisciplinary applications without borders. In terms of developing general frameworks for theoretical foundations and real-world applications, it discusses a number of new classes of generalised second-order invex functions and second-order univex functions, new sets of second-order necessary optimality conditions, second-order sufficient optimality conditions, and second-order duality models for establishing numerous duality theorems for discrete minmax (or maxmin) semi-infinite fractional programming problems. In the current interdisciplinary supercomputer-oriented research envi...
Fractionation method for soil microelements
Energy Technology Data Exchange (ETDEWEB)
Shuman, L.M.
1985-07-01
To evaluate a sequential extraction procedure to separate chemical forms of soil microelements, I fractionated 16 soils, both surface and subsoils. The purpose of the sequential extractions was to solubilize the Mn, Cu, Fe, and Zn in the exchangeable, organic matter, Mn oxide, amorphous Fe oxide, and crystalline Fe oxide fractions. The solid portion remaining was separated into sand, silt, and clay sizes, and each was dissolved and analyzed for the above elements. Soil properties were determined, and whole soils were analyzed for total microelement content.
On a fractional difference operator
Directory of Open Access Journals (Sweden)
P. Baliarsingh
2016-06-01
Full Text Available In the present article, a set of new difference sequence spaces of fractional order has been introduced and subsequently, an application of these spaces, the notion of the derivatives and the integrals of a function to the case of non-integer order have been generalized. Certain results involving the unusual and non-uniform behavior of the corresponding difference operator have been investigated and also been verified by using some counter examples. We also verify these unusual and non-uniform behaviors by studying the geometry of fractional calculus.
Applied survival analysis using R
Moore, Dirk F
2016-01-01
Applied Survival Analysis Using R covers the main principles of survival analysis, gives examples of how it is applied, and teaches how to put those principles to use to analyze data using R as a vehicle. Survival data, where the primary outcome is time to a specific event, arise in many areas of biomedical research, including clinical trials, epidemiological studies, and studies of animals. Many survival methods are extensions of techniques used in linear regression and categorical data, while other aspects of this field are unique to survival data. This text employs numerous actual examples to illustrate survival curve estimation, comparison of survivals of different groups, proper accounting for censoring and truncation, model variable selection, and residual analysis. Because explaining survival analysis requires more advanced mathematics than many other statistical topics, this book is organized with basic concepts and most frequently used procedures covered in earlier chapters, with more advanced topics...
DOWN, JD; BOUDEWIJN, A; VANOS, R; THAMES, HD; PLOEMACHER, RE
1995-01-01
The radiation dose-survival of various hematopoietic cell subsets in murine bone marrow (BM) was determined in the cobblestone area forming cell (CAFC) assay under conditions of single-, split-, and multiple-dose irradiation. A greater recovery in cell survival with decreasing dose per fraction, or
Haque, Sahena
2014-04-01
Taking up a new consultant post can be both exciting and daunting. Once the elation of completing years of training and successfully securing a valued position has subsided, the reality of the task ahead becomes apparent. A new consultant needs to develop a number of skills to develop as a clinical leader and understand the processes within the National Health Service (NHS) that enable service development and innovation. In a programme packed with esteemed speakers, the Royal College of Physicians' one-day conference, Consultants' survival guide: how to succeed as a new consultant provided practical tips and advice for senior trainees and new consultants.
Survival curves for irradiated cells
International Nuclear Information System (INIS)
Gibson, D.K.
1975-01-01
The subject of the lecture is the probability of survival of biological cells which have been subjected to ionising radiation. The basic mathematical theories of cell survival as a function of radiation dose are developed. A brief comparison with observed survival curves is made. (author)
On a Fractional Binomial Process
Cahoy, Dexter O.; Polito, Federico
2012-02-01
The classical binomial process has been studied by Jakeman (J. Phys. A 23:2815-2825, 1990) (and the references therein) and has been used to characterize a series of radiation states in quantum optics. In particular, he studied a classical birth-death process where the chance of birth is proportional to the difference between a larger fixed number and the number of individuals present. It is shown that at large times, an equilibrium is reached which follows a binomial process. In this paper, the classical binomial process is generalized using the techniques of fractional calculus and is called the fractional binomial process. The fractional binomial process is shown to preserve the binomial limit at large times while expanding the class of models that include non-binomial fluctuations (non-Markovian) at regular and small times. As a direct consequence, the generality of the fractional binomial model makes the proposed model more desirable than its classical counterpart in describing real physical processes. More statistical properties are also derived.
Fractional Trajectories: Decorrelation Versus Friction
2013-07-27
numerical solutions of fractional-order predator–prey and rabies models, J. Math. Anal. Appl. 325 (2007) 542–553. [6] D. West, B.J. West, On allometry...E 70 (2004) 051103. [17] E.W. Montroll, G.H. Weiss, Random walks on lattices . II, J. Math. Phys. 6 (1965) 167–181. [18] R. Metzler, J. Klafter, The
Complexity and the Fractional Calculus
2013-01-01
and H. A. A. El-Saka, “Equi- librium points, stability and numerical solutions of fractional- order predator-prey and rabies models,” Journal of...Montroll and G. H. Weiss, “Random walks on lattices . II,” Journal of Mathematical Physics, vol. 6, pp. 167–181, 1965. [35] J.-P. Bouchaud and A. Georges
Mokashi, Neelima A.
2009-01-01
This article depicts the rewarding experience of creating mathematical environments for kindergarten and elementary students by focusing on one of the most important and often difficult-to-grasp concepts (fractions) through play methods incorporated into a math fair. The basic concept of a math fair is threefold: (1) to create preplanned,…
Riesz potential versus fractional Laplacian
Ortigueira, Manuel Duarte
2014-09-01
This paper starts by introducing the Grünwald-Letnikov derivative, the Riesz potential and the problem of generalizing the Laplacian. Based on these ideas, the generalizations of the Laplacian for 1D and 2D cases are studied. It is presented as a fractional version of the Cauchy-Riemann conditions and, finally, it is discussed with the n-dimensional Laplacian.
Geodesic continued fractions and LLL
Beukers, F
2014-01-01
We discuss a proposal for a continued fraction-like algorithm to determine simultaneous rational approximations to dd real numbers α1,…,αdα1,…,αd. It combines an algorithm of Hermite and Lagarias with ideas from LLL-reduction. We dynamically LLL-reduce a quadratic form with parameter tt as t↓0t↓0.
Fractional Processes and Fractional-Order Signal Processing Techniques and Applications
Sheng, Hu; Qiu, TianShuang
2012-01-01
Fractional processes are widely found in science, technology and engineering systems. In Fractional Processes and Fractional-order Signal Processing, some complex random signals, characterized by the presence of a heavy-tailed distribution or non-negligible dependence between distant observations (local and long memory), are introduced and examined from the ‘fractional’ perspective using simulation, fractional-order modeling and filtering and realization of fractional-order systems. These fractional-order signal processing (FOSP) techniques are based on fractional calculus, the fractional Fourier transform and fractional lower-order moments. Fractional Processes and Fractional-order Signal Processing: • presents fractional processes of fixed, variable and distributed order studied as the output of fractional-order differential systems; • introduces FOSP techniques and the fractional signals and fractional systems point of view; • details real-world-application examples of FOSP techniques to demonstr...
International Nuclear Information System (INIS)
Kearney, C.H.
1979-09-01
This book includes chapters on psychological preparations, warning and communications, and evacuation. It describes the building of expedient shelters, their ventilation and cooling, the purification and storage of adequate water, the processing and cooking of whole grains and legumes, fallout meters, protection against fires and carbon monoxide, and expedient furnishings for shelters. Other chapters cover sanitation and preventive medicine, medical advice for nuclear survivors lacking the help of doctors, improvised footwear and clothing, and advice on minimum preparations that can be made at low cost and should be made before a crisis arises. One appendix of the handbook gives detailed, field-tested instructions for building six types of earth-covered expedient fallout shelters, with criteria to guide the choice of which shelter to build. Others contain instructions for making an efficient shelter-ventilating pump and a homemade fallout meter that is accurate and dependable with inexpensive materials found in most households. This report is primarily a compilation and summary of civil defense measures and inventions developed at ORNL over the past 14 years and field-tested in six states, from Florida to Utah. It is the first comprehensive handbook of survival information for use by untrained citizens who want to improve their chances of surviving a possible nuclear attack. Sections may be easily excerpted and reproduced for mass distribution through news media
International Nuclear Information System (INIS)
Yazici, Gozde; Kiratli, Hayyam; Ozyigit, Gokhan; Sari, Sezin Yuce; Cengiz, Mustafa; Tarlan, Bercin; Mocan, Burce Ozgen; Zorlu, Faruk
2017-01-01
Purpose: To evaluate treatment results of stereotactic radiosurgery or fractionated stereotactic radiation therapy (SRS/FSRT) for uveal melanoma. Methods and Materials: We retrospectively evaluated 181 patients with 182 uveal melanomas receiving SRS/FSRT between 2007 and 2013. Treatment was administered with CyberKnife. Results: According to Collaborative Ocular Melanoma Study criteria, tumor size was small in 1%, medium in 49.5%, and large in 49.5% of the patients. Seventy-one tumors received <45 Gy, and 111 received ≥45 Gy. Median follow-up time was 24 months. Complete and partial response was observed in 8 and 104 eyes, respectively. The rate of 5-year overall survival was 98%, disease-free survival 57%, local recurrence-free survival 73%, distant metastasis-free survival 69%, and enucleation-free survival 73%. There was a significant correlation between tumor size and disease-free survival, SRS/FSRT dose and enucleation-free survival; and both were prognostic for local recurrence-free survival. Enucleation was performed in 41 eyes owing to progression in 26 and complications in 11. Conclusions: The radiation therapy dose is of great importance for local control and eye retention; the best treatment outcome was achieved using ≥45 Gy in 3 fractions.
Energy Technology Data Exchange (ETDEWEB)
Yazici, Gozde [Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara (Turkey); Kiratli, Hayyam [Department of Ophthalmology, Faculty of Medicine, Hacettepe University, Ankara (Turkey); Ozyigit, Gokhan; Sari, Sezin Yuce; Cengiz, Mustafa [Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara (Turkey); Tarlan, Bercin [Bascom Palmer Eye Institute, Miami, Florida (United States); Mocan, Burce Ozgen [Department of Radiology, Faculty of Medicine, Hacettepe University, Ankara (Turkey); Zorlu, Faruk, E-mail: fzorlu@hacettepe.edu.tr [Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara (Turkey)
2017-05-01
Purpose: To evaluate treatment results of stereotactic radiosurgery or fractionated stereotactic radiation therapy (SRS/FSRT) for uveal melanoma. Methods and Materials: We retrospectively evaluated 181 patients with 182 uveal melanomas receiving SRS/FSRT between 2007 and 2013. Treatment was administered with CyberKnife. Results: According to Collaborative Ocular Melanoma Study criteria, tumor size was small in 1%, medium in 49.5%, and large in 49.5% of the patients. Seventy-one tumors received <45 Gy, and 111 received ≥45 Gy. Median follow-up time was 24 months. Complete and partial response was observed in 8 and 104 eyes, respectively. The rate of 5-year overall survival was 98%, disease-free survival 57%, local recurrence-free survival 73%, distant metastasis-free survival 69%, and enucleation-free survival 73%. There was a significant correlation between tumor size and disease-free survival, SRS/FSRT dose and enucleation-free survival; and both were prognostic for local recurrence-free survival. Enucleation was performed in 41 eyes owing to progression in 26 and complications in 11. Conclusions: The radiation therapy dose is of great importance for local control and eye retention; the best treatment outcome was achieved using ≥45 Gy in 3 fractions.
Kavvas, M. Levent; Tu, Tongbi; Ercan, Ali; Polsinelli, James
2017-10-01
Using fractional calculus, a dimensionally consistent governing equation of transient, saturated groundwater flow in fractional time in a multi-fractional confined aquifer is developed. First, a dimensionally consistent continuity equation for transient saturated groundwater flow in fractional time and in a multi-fractional, multidimensional confined aquifer is developed. For the equation of water flux within a multi-fractional multidimensional confined aquifer, a dimensionally consistent equation is also developed. The governing equation of transient saturated groundwater flow in a multi-fractional, multidimensional confined aquifer in fractional time is then obtained by combining the fractional continuity and water flux equations. To illustrate the capability of the proposed governing equation of groundwater flow in a confined aquifer, a numerical application of the fractional governing equation to a confined aquifer groundwater flow problem was also performed.
Modulation of haemopoietic radiation response of mice by diclofenac in fractionated treatment
International Nuclear Information System (INIS)
Hofer, M.; Pospisil, M.; Pipalova, I.; Hola, J.
1996-01-01
The effects were studied of diclofenac, an inhibitor of prostaglandin synthesis, on the acute radiation syndrome elicited in mice by fractionated irradiation. Several hematological parameters were evaluated in mice irradiated with 5x 2 Gy and 3x, 4x, or 5x 3 Gy (intervals between fractions 24 h) from a 60 Co gamma source. The animals were treated with diclofenac either before each fraction or only once before the last fraction. The survival of mice was recorded after the irradiation regimen of 5x 3 Gy followed by a ''top-up'' dose of 3.5 Gy given 24 h after the last radiation fraction. Statistically significant enhancement of the endogenous spleen colony and of leukopoiesis was found in mice treated with diclofenac repeatedly, as compared with both saline-treated irradiated controls and animals administered a single diclofenac dose, if a sublethal total radiation dose had been accumulated. However, following accumulation of a lethal radiation dose, slightly impaired survival was observed in mice given diclofenac. It follows from the results that diclofenac is a suitable drug for enhancing leukopoisesis impaired by sublethal fractionated irradiation. Nevertheless, the undesirable side effects of this drug affect adversely the survival of the experimental animals following a lethal accumulated radiation dose. 3 tabs., 3 figs.,32 refs
Note on fractional Mellin transform and applications.
Kılıçman, Adem; Omran, Maryam
2016-01-01
In this article, we define the fractional Mellin transform by using Riemann-Liouville fractional integral operator and Caputo fractional derivative of order [Formula: see text] and study some of their properties. Further, some properties are extended to fractional way for Mellin transform.
On the fractional calculus of Besicovitch function
International Nuclear Information System (INIS)
Liang Yongshun
2009-01-01
Relationship between fractional calculus and fractal functions has been explored. Based on prior investigations dealing with certain fractal functions, fractal dimensions including Hausdorff dimension, Box dimension, K-dimension and Packing dimension is shown to be a linear function of order of fractional calculus. Both Riemann-Liouville fractional calculus and Weyl-Marchaud fractional derivative of Besicovitch function have been discussed.
Surviving relatives after suicide
DEFF Research Database (Denmark)
Nørrelykke, Helle; Cohrt, Pernille
We would like to focus on the surviving relatives after suicides, because it is generally accepted that it is especially difficult to recover after the loss from suicide and because we know as a fact that one suicide affects five persons on average. Every year approximately 700 people commit...... suicide in Denmark. This means that at least 400 people undergo the trauma it is when one of their near relatives commits suicide. We also know that the loss from suicide involves a lot of conflicting feelings - like anger, shame, guilt and loss and that the lack of therapy/treatment of these difficult...... for treatment for the relatives. In the wake of this policy document a national organization for relatives after suicide and a national network for those who attempt suicide occurred. Both organizations are formed by voluntary subscription and both organizations offer acute emergency relief, conversation groups...
International Nuclear Information System (INIS)
He, Ji-Huan; Elagan, S.K.; Li, Z.B.
2012-01-01
The fractional complex transform is suggested to convert a fractional differential equation with Jumarie's modification of Riemann–Liouville derivative into its classical differential partner. Understanding the fractional complex transform and the chain rule for fractional calculus are elucidated geometrically. -- Highlights: ► The chain rule for fractional calculus is invalid, a counter example is given. ► The fractional complex transform is explained geometrically. ► Fractional equations can be converted into differential equations.
Fractionated dose studies with X-rays and various alkylating agents in P388 mouse lymphoma cells
International Nuclear Information System (INIS)
Anderson, D.
1981-01-01
The fractionated dose technique was used in P388F cells to examine the effects of X-rays and four alkylating agents on survival and induction of 5-iodo-2-deoxyuridine (IudR) resistant variants. Fractionation intervals up to 51/2 h were used for X-rays and for the alkylating agents up to 192 h. Fractionation of the X-ray dose resulted in a sparing effect for survival and variant induction. A sparing effect was also observed for survival after treatment with alkylating agents. However, variant frequencies were observed as large as or greater than those produced by the full doses of alkylating agents. For such agents this would suggest that survival and variant induction are independent events. Differences in the effects of X-rays and alkylating agents cannot be explained by differences in growth rate or the recovery of viability after treatment. (author)
Fractionated dose studies with X-rays and various alkylating agents in P388 mouse lymphoma cells
International Nuclear Information System (INIS)
Anderson, D.
1981-01-01
The fractionated dose technique has been used in P388F cells to examine the effects of X-rays and four alkylating agents on survival and induction of 5-iodo-2-deoxyuridine (IudR) resistant variants. Fractionation intervals up to 5 1/2 h were used for X-rays and for the alkylating agents up to 192 h. Fractionation of the X-ray dose resulted in a sparing effect for survival and variant induction. A sparing effect was also observed for survival after treatment with alkylating agents. However, variant frequencies were observed as large as or greater than those produced by the full doses of alkylating agents. For such agents this would suggest that survival and variant induction are independent events. Differences in the effects of X-rays and alkylating agents cannot be explained by differences in growth rate or the recovery of viability after treatment
Complexity and the Fractional Calculus
Directory of Open Access Journals (Sweden)
Pensri Pramukkul
2013-01-01
Full Text Available We study complex processes whose evolution in time rests on the occurrence of a large and random number of events. The mean time interval between two consecutive critical events is infinite, thereby violating the ergodic condition and activating at the same time a stochastic central limit theorem that supports the hypothesis that the Mittag-Leffler function is a universal property of nature. The time evolution of these complex systems is properly generated by means of fractional differential equations, thus leading to the interpretation of fractional trajectories as the average over many random trajectories each of which satisfies the stochastic central limit theorem and the condition for the Mittag-Leffler universality.
Intelligent fractions learning system: implementation
CSIR Research Space (South Africa)
Smith, Andrew C
2011-05-01
Full Text Available to capture and analyse the children?s interactions), the scalability of the system makes it attractive in applications where automatic data capture is required. This paper is structured as follows. First, we describe the objectives of the system. Next we... to fractions. Our aim with the current research project is to extend the existing UFractions learning system to incorporate automatic data capturing. ?Intelligent UFractions? allows a teacher to remotely monitor the children?s progress during...
Microfluidic Devices for Blood Fractionation
Hou, Han Wei; Bhagat, Ali Asgar S.; Lee, Wong Cheng J.; Huang, Sha; Han, Jongyoon; Lim, Chwee Teck
2011-01-01
Blood, a complex biological fluid, comprises 45% cellular components suspended in protein rich plasma. These different hematologic components perform distinct functions in vivo and thus the ability to efficiently fractionate blood into its individual components has innumerable applications in both clinical diagnosis and biological research. Yet, processing blood is not trivial. In the past decade, a flurry of new microfluidic based technologies has emerged to address this compelling problem. ...
Fractional viscoelastic beam under torsion
Colinas-Armijo, N.; Cutrona, S.; Di Paola, M.; Pirrotta, A.
2017-07-01
This paper introduces a study on twisted viscoelastic beams, having considered fractional calculus to capture the viscoelastic behaviour. Further another novelty of this paper is extending a recent numerical approach, labelled line elementless method (LEM), to viscoelastic beams. The latter does not require any discretization neither in the domain nor in the boundary. Some numerical applications have been reported to demonstrate the efficiency and accuracy of the method.
FRACTIONAL DYNAMICS AT MULTIPLE TIMES
Meerschaert, Mark M.; Straka, Peter
2012-01-01
A continuous time random walk (CTRW) imposes a random waiting time between random particle jumps. CTRW limit densities solve a fractional Fokker-Planck equation, but since the CTRW limit is not Markovian, this is not sufficient to characterize the process. This paper applies continuum renewal theory to restore the Markov property on an expanded state space, and compute the joint CTRW limit density at multiple times.
FRACTIONAL DYNAMICS AT MULTIPLE TIMES.
Meerschaert, Mark M; Straka, Peter
2012-11-01
A continuous time random walk (CTRW) imposes a random waiting time between random particle jumps. CTRW limit densities solve a fractional Fokker-Planck equation, but since the CTRW limit is not Markovian, this is not sufficient to characterize the process. This paper applies continuum renewal theory to restore the Markov property on an expanded state space, and compute the joint CTRW limit density at multiple times.
Fungal survival in ensiled swine faeces.
Serrano-García, E; Castrejón-Pineda, F; Herradora-Lozano, M A; Ramírez-Pérez, A H; Angeles-Campos, S; Buntinx, S E
2008-06-01
The survival of several genera of fungi was determined in the ensiled solid fraction of swine faeces after 0, 7, 14, 28 and 56 days of ensiling. The experiment had two treatments, un-ensiled and ensiled manure, in a split-plot design. The manure was distributed into 50 containers; samples, taken at the specified times, were cultured in agar potato dextrose medium, incubated, and colony forming units (CFU/g) were counted and log-transformed. The ensiling process decreased the number of CFU after 56 days. Five fungal genera were identified (Absidia spp., Aspergillus spp., Penicillium spp., Rhizopus spp. and non-fructiferous fungi), and their vulnerability to the ensiling conditions varied, although most of them slowed their growth or disappeared after 14 days of ensiling.
Chest compression rates and survival following out-of-hospital cardiac arrest.
Idris, Ahamed H; Guffey, Danielle; Pepe, Paul E; Brown, Siobhan P; Brooks, Steven C; Callaway, Clifton W; Christenson, Jim; Davis, Daniel P; Daya, Mohamud R; Gray, Randal; Kudenchuk, Peter J; Larsen, Jonathan; Lin, Steve; Menegazzi, James J; Sheehan, Kellie; Sopko, George; Stiell, Ian; Nichol, Graham; Aufderheide, Tom P
2015-04-01
Guidelines for cardiopulmonary resuscitation recommend a chest compression rate of at least 100 compressions/min. A recent clinical study reported optimal return of spontaneous circulation with rates between 100 and 120/min during cardiopulmonary resuscitation for out-of-hospital cardiac arrest. However, the relationship between compression rate and survival is still undetermined. Prospective, observational study. Data is from the Resuscitation Outcomes Consortium Prehospital Resuscitation IMpedance threshold device and Early versus Delayed analysis clinical trial. Adults with out-of-hospital cardiac arrest treated by emergency medical service providers. None. Data were abstracted from monitor-defibrillator recordings for the first five minutes of emergency medical service cardiopulmonary resuscitation. Multiple logistic regression assessed odds ratio for survival by compression rate categories (compression fraction and depth, first rhythm, and study site. Compression rate data were available for 10,371 patients; 6,399 also had chest compression fraction and depth data. Age (mean±SD) was 67±16 years. Chest compression rate was 111±19 per minute, compression fraction was 0.70±0.17, and compression depth was 42±12 mm. Circulation was restored in 34%; 9% survived to hospital discharge. After adjustment for covariates without chest compression depth and fraction (n=10,371), a global test found no significant relationship between compression rate and survival (p=0.19). However, after adjustment for covariates including chest compression depth and fraction (n=6,399), the global test found a significant relationship between compression rate and survival (p=0.02), with the reference group (100-119 compressions/min) having the greatest likelihood for survival. After adjustment for chest compression fraction and depth, compression rates between 100 and 120 per minute were associated with greatest survival to hospital discharge.
Fractional Sums and Differences with Binomial Coefficients
Directory of Open Access Journals (Sweden)
Thabet Abdeljawad
2013-01-01
Full Text Available In fractional calculus, there are two approaches to obtain fractional derivatives. The first approach is by iterating the integral and then defining a fractional order by using Cauchy formula to obtain Riemann fractional integrals and derivatives. The second approach is by iterating the derivative and then defining a fractional order by making use of the binomial theorem to obtain Grünwald-Letnikov fractional derivatives. In this paper we formulate the delta and nabla discrete versions for left and right fractional integrals and derivatives representing the second approach. Then, we use the discrete version of the Q-operator and some discrete fractional dual identities to prove that the presented fractional differences and sums coincide with the discrete Riemann ones describing the first approach.
Ship Systems Survivability Test Site
Federal Laboratory Consortium — Area for testing survivability of shipboard systems to include electrical, communications, and fire suppression. Multipurpose test range for supporting gun firing,...
Impact of radiation therapy fraction size on local control of early glottic carcinoma
International Nuclear Information System (INIS)
Yu, Edward; Shenouda, George; Beaudet, Marie P.; Black, Martin J.
1997-01-01
Purpose: Different radiotherapy fractionation schedules were used over a 10-year period to treat patients with early squamous cell carcinoma of the vocal cords at McGill University. A retrospective analysis was performed to study the effect of fraction size on local control in this group of patients. Methods and Materials: A total of 126 previously untreated patients with T1 invasive squamous cell carcinoma of the true vocal cords were irradiated between January 1978 and December 1988 in the Department of Radiation Oncology at McGill University. All patients received megavoltage irradiation, 94 patients received daily fractions > 2 Gy (64 patients received 50 Gy with once-daily 2.5-Gy fractions, and 30 received 65.25 Gy in 29 fractions of 2.25 Gy each), and 32 patients were treated to a dose of 66 Gy in 33 fractions with 2 Gy/fraction. Patients' characteristics of prognostic importance were equally distributed between the two fractionation groups. Results: At a median follow-up of 84 months, the 10-year disease-free survival and overall survival were 76% and 93%, respectively. Local control for patients treated with > 2 Gy fraction was 84%, compared to 65.6% for those treated with 2-Gy fractions (p = 0.026). Among the prognostic factors tested, such as gender, age, stage, anterior and posterior commissure involvement, smoking history, and fraction size, the latter was the only significant predictor of local control for the whole group of patients in univariate (p = 0.041) and multivariate (p = 0.023) analysis. There was no observed difference in the incidence of complications between the two fraction groups. Conclusions: From the results of this retrospective review of patients treated with radiotherapy for T1 true vocal cord cancer, and within the range of total doses and overall treatment times used in our patients, it was found that fractionation schedules using daily fraction size > 2 Gy are associated with a better local control than schedules delivering 2 Gy/fraction
Low power constant fraction discriminator
International Nuclear Information System (INIS)
Krishnan, Shanti; Raut, S.M.; Mukhopadhyay, P.K.
2001-01-01
This paper describes the design of a low power ultrafast constant fraction discriminator, which significantly reduces the power consumption. A conventional fast discriminator consumes about 1250 MW of power whereas this low power version consumes about 440 MW. In a multi detector system, where the number of discriminators is very large, reduction of power is of utmost importance. This low power discriminator is being designed for GRACE (Gamma Ray Atmospheric Cerenkov Experiments) telescope where 1000 channels of discriminators are required. A novel method of decreasing power consumption has been described. (author)
Natural fractionation of uranium isotopes
International Nuclear Information System (INIS)
Noordmann, Janine
2015-01-01
The topic of this thesis was the investigation of U (n( 238 U) / n( 235 U)) isotope variations in nature with a focus on samples (1) that represent the continental crust and its weathering products (i.e. granites, shales and river water) (2) that represent products of hydrothermal alteration on mid-ocean ridges (i.e. altered basalts, carbonate veins and hydrothermal water) and (3) from restricted euxinic basins (i.e. from the water column and respective sediments). The overall goal was to explore the environmental conditions and unravel the mechanisms that fractionate the two most abundant U isotopes, n( 238 U) and n( 235 U), on Earth.
Fractional ablative erbium YAG laser
DEFF Research Database (Denmark)
Taudorf, Elisabeth H; Haak, Christina S; Erlendsson, Andrés M
2014-01-01
BACKGROUND AND OBJECTIVES: Treatment of a variety of skin disorders with ablative fractional lasers (AFXL) is driving the development of portable AFXLs. This study measures micropore dimensions produced by a small 2,940 nm AFXL using a variety of stacked pulses, and determines a model correlating...... energies of 2.3-12.8 mJ/microbeam and total energy levels of 4.6-640 mJ/microchannel. Histological endpoints were ablation depth (AD), coagulation zone (CZ) and ablation width (AW). Data were logarithmically transformed if required prior to linear regression analyses. Results for histological endpoints...
Survival of seeds in hypervelocity impacts
Jerling, Aaron; Burchell, Mark J.; Tepfer, David
2008-10-01
Panspermia (‘seeds everywhere’) postulates that life naturally migrates through space. Laboratory studies of Panspermia often examine the survival of Earth's species under the conditions thought to occur during transfer through space. Much of this research has centred on bacteria, but here we consider seeds themselves. We simulated the extreme accelerations necessary for their hypothetical ejection from a planetary surface and the impacts associated with their arrival on another planet. Seeds of tobacco, alfalfa and cress were fired into water at speeds in the range 1 3 km s-1, corresponding to impact shock pressures of circa 0.24 2.4 GPa. No seeds remained intact and able to germinate, even at the lowest speeds. Although fragmentation occurred, even at 3 km s-1 the size of some of the fragments was about 25% that of the seeds. Thus, whilst the seeds themselves did not survive extreme shocks, a substantial fraction of their mass did and might successfully deliver complex organic materials after impact. These results are discussed with respect to ancient Panspermia and the potential of contemporary impacts to eject living organisms into space.
Directory of Open Access Journals (Sweden)
Yong-Ju Yang
2013-01-01
Full Text Available The local fractional variational iteration method for local fractional Laplace equation is investigated in this paper. The operators are described in the sense of local fractional operators. The obtained results reveal that the method is very effective.
International Nuclear Information System (INIS)
Kearny, C.H.
1982-01-01
This book brings together field-tested instructions that, if followed by a large fraction of Americans during a crisis that preceded an attack, could save millions of lives. Myths and facts about consequences of a massive nuclear attack are discussed. The main emphasis, however, is on preparations that could be made in the last few days of a worsening crisis. This book includes chapters on psychological preparations, warning and communications, and evacuation. These chapters describe the building of expedient shelters, their ventilation and cooling, the purification and storage of adequate water, the processing and cooking of whole grains and legumes, fallout meters, protection against fires and carbon monoxide, and expedient furnishings for shelters. Other chapters cover sanitation and preventive medicine, medical advice for nuclear survivors lacking the help of doctors, improvised footwear and clothing, and advice on minimum preparations that can be made at low cost and should be made before a crisis arises. One appendix gives detailed, field-tested instructions for building six types of earth-covered expedient fallout shelters, with criteria to guide the choice of which shelter to build. The design features of several types of expedient blast shelters are described in another appendix. Two others contain instructions for making an efficient shelter-ventilating pump and a homemade fallout meter that is accurate and dependable using inexpensive materials found in most households. The report is primarily a compilation and summary of civil defense measures and inventions developed at ORNL over the past 14 years and field-tested in six states, from Florida to Utah, for use by untrained citizens
THE NEW SOLUTION OF TIME FRACTIONAL WAVE EQUATION WITH CONFORMABLE FRACTIONAL DERIVATIVE DEFINITION
Çenesiz, Yücel; Kurt, Ali
2015-01-01
– In this paper, we used new fractional derivative definition, the conformable fractional derivative, for solving two and three dimensional time fractional wave equation. This definition is simple and very effective in the solution procedures of the fractional differential equations that have complicated solutions with classical fractional derivative definitions like Caputo, Riemann-Liouville and etc. The results show that conformable fractional derivative definition is usable and convenient ...
Global Activities and Plant Survival
DEFF Research Database (Denmark)
Bandick, Roger
2014-01-01
the highest exit rates. Moreover, the exit rates of globally engaged plants seem to be unaffected by increased foreign presence, whereas there appears to be a negative impact on the survival rates of non-exporting non-MNE plants. Finally, the result reveals that the survival ratio of plants of acquired...
Radionuclide blood cell survival studies
International Nuclear Information System (INIS)
Bentley, S.A.; Miller, D.T.
1986-01-01
Platelet and red cell survival studies are reviewed. The use of 51 Cr and di-isopropylfluoridate labelled with tritium or 32 P is discussed for red cell survival study and 51 Cr and 111 In-oxine are considered as platelet labels. (UK)
Fractional Transforms in Optical Information Processing
Directory of Open Access Journals (Sweden)
Maria Luisa Calvo
2005-06-01
Full Text Available We review the progress achieved in optical information processing during the last decade by applying fractional linear integral transforms. The fractional Fourier transform and its applications for phase retrieval, beam characterization, space-variant pattern recognition, adaptive filter design, encryption, watermarking, and so forth is discussed in detail. A general algorithm for the fractionalization of linear cyclic integral transforms is introduced and it is shown that they can be fractionalized in an infinite number of ways. Basic properties of fractional cyclic transforms are considered. The implementation of some fractional transforms in optics, such as fractional Hankel, sine, cosine, Hartley, and Hilbert transforms, is discussed. New horizons of the application of fractional transforms for optical information processing are underlined.
Boundary Controllability of Nonlinear Fractional Integrodifferential Systems
Directory of Open Access Journals (Sweden)
Ahmed HamdyM
2010-01-01
Full Text Available Sufficient conditions for boundary controllability of nonlinear fractional integrodifferential systems in Banach space are established. The results are obtained by using fixed point theorems. We also give an application for integropartial differential equations of fractional order.
Fractional Order Element Based Impedance Matching
Radwan, Ahmed Gomaa
2014-06-24
Disclosed are various embodiments of methods and systems related to fractional order element based impedance matching. In one embodiment, a method includes aligning a traditional Smith chart (|.alpha.|=1) with a fractional order Smith chart (|.alpha.|.noteq.1). A load impedance is located on the traditional Smith chart and projected onto the fractional order Smith chart. A fractional order matching element is determined by transitioning along a matching circle of the fractional order Smith chart based at least in part upon characteristic line impedance. In another embodiment, a system includes a fractional order impedance matching application executed in a computing device. The fractional order impedance matching application includes logic that obtains a first set of Smith chart coordinates at a first order, determines a second set of Smith chart coordinates at a second order, and determines a fractional order matching element from the second set of Smith chart coordinates.
Multiple Interactive Representations for Fractions Learning
Feenstra, Laurens; Aleven, Vincent; Rummel, Nikol; Taatgen, Niels; Aleven,; Kay, J; Mostow, J
2010-01-01
Multiple External Representations (MERs) have been used successfully in instructional activities, including fractions However, students often have difficulties making the connections between the MERs spontaneously We argue that interactive fraction representations may help students in discovering
Microfluidic Devices for Blood Fractionation
Directory of Open Access Journals (Sweden)
Chwee Teck Lim
2011-07-01
Full Text Available Blood, a complex biological fluid, comprises 45% cellular components suspended in protein rich plasma. These different hematologic components perform distinct functions in vivo and thus the ability to efficiently fractionate blood into its individual components has innumerable applications in both clinical diagnosis and biological research. Yet, processing blood is not trivial. In the past decade, a flurry of new microfluidic based technologies has emerged to address this compelling problem. Microfluidics is an attractive solution for this application leveraging its numerous advantages to process clinical blood samples. This paper reviews the various microfluidic approaches realized to successfully fractionate one or more blood components. Techniques to separate plasma from hematologic cellular components as well as isolating blood cells of interest including certain rare cells are discussed. Comparisons based on common separation metrics including efficiency (sensitivity, purity (selectivity, and throughput will be presented. Finally, we will provide insights into the challenges associated with blood-based separation systems towards realizing true point-of-care (POC devices and provide future perspectives.
Directory of Open Access Journals (Sweden)
J. Vierinen
2011-06-01
Full Text Available We present a novel approach for modulating radar transmissions in order to improve target range and Doppler estimation accuracy. This is achieved by using non-uniform baud lengths. With this method it is possible to increase sub-baud range-resolution of phase coded radar measurements while maintaining a narrow transmission bandwidth. We first derive target backscatter amplitude estimation error covariance matrix for arbitrary targets when estimating backscatter in amplitude domain. We define target optimality and discuss different search strategies that can be used to find well performing transmission envelopes. We give several simulated examples of the method showing that fractional baud-length coding results in smaller estimation errors than conventional uniform baud length transmission codes when estimating the target backscatter amplitude at sub-baud range resolution. We also demonstrate the method in practice by analyzing the range resolved power of a low-altitude meteor trail echo that was measured using a fractional baud-length experiment with the EISCAT UHF system.
Process scheme simulation of gases and liquid fraction fractionation
International Nuclear Information System (INIS)
Rikalovska, Tatjana; Markovska, Liljana; Meshko, Vera
1999-01-01
Computer programs based on the models of process equipment are used in process development, equipment design and technology operation. Flowsheet programs has become the major tools which are used in process design and modernization of the existing processes of chemical technology. The flowsheet programs are used to examine the process, and different alternatives of each process. The simulations have been made for the process of gas recovery of gas. and liquid fractions in OKTA-Skopje by using the process simulator UNIOPT. Simulation of existing scheme has been made progressively by including the model of equipment. In this way the required database is formed for the simulation and study of different alternatives of this process. The complete design of the distillation column for separation of propane and butane has been made by DISTIL. The results obtained by simulation agree very well with the data of the real process in OKTA Crude Oil Refinery in Skopje. (Author)
The synchronization of three fractional differential systems
International Nuclear Information System (INIS)
Li Changpin; Yan Jianping
2007-01-01
In this paper, a new method is proposed and applied to the synchronization of fractional differential systems (or 'differential systems with fractional orders'), where both drive and response systems have the same dimensionality and are coupled by the driving signal. The present technique is based on the stability criterion of linear fractional systems. This method is implemented in (chaos) synchronization of the fractional Lorenz system, Chen system and Chua circuit. Numerical simulations show the present synchronization method works well
Statistical Inference for Fractional Diffusion Processes
Rao, B L S Prakasa
2010-01-01
Statistical Inference for Fractional Diffusion Processes looks at statistical inference for stochastic processes modeled by stochastic differential equations driven by fractional Brownian motion. Other related processes, such as sequential inference, nonparametric and non parametric inference and parametric estimation are also discussed. The book will deal with Fractional Diffusion Processes (FDP) in relation to statistical influence for stochastic processes. The books main focus is on parametric and non parametric inference problems for fractional diffusion processes when a complete path of t
International Nuclear Information System (INIS)
Baumert, Brigitta G.; Lutterbach, Johannes; Bernays, Rene; Davis, J. Bernard; Heppner, Frank L.
2003-01-01
Purpose: To determine the value and the toxicity of an additional fractionated stereotactic boost as used in the joint randomized EORTC-22972/MRC-BR10 study in patients with malignant gliomas. Materials and methods: Seventeen patients (11 male, six female) with a high-grade glioma (two WHO III, 15 WHO IV) ≤4 cm in maximum diameter, with a good performance status (WHO ≥2), were treated with a fractionated stereotactic radiotherapy (SRT) boost to 20 Gy in four fractions following partial brain irradiation to a dose of 60 Gy in 30 fractions. This patient group was compared with historical data in a matched-pair analysis. Results: All patients were treated by conventional radiotherapy and a SRT boost (15 patients received 20 Gy and two patients 10 Gy). Acute side effects included fatigue (two), impairment of short-term memory (one) and worsening of pre-existing symptoms (one). No patient developed steroid dependence after SRT. One patient was re-operated for radiation necrosis. At a median follow-up of 25 months (9-50 months) 14 patients recurred locally. Survival was 77% at 1 year and 42% at 2 years; progression-free survival was 70% at 1 year and 35% at 2 years for all patients, respectively. Median survival for the whole patient group is 20 months. Comparison with a matched historical group showed a significantly better survival for the group treated with a stereotactic boost (P<0.0001). Conclusion: A fractionated stereotactic boost after standard external beam radiotherapy in selected patients with high-grade glioma is feasible and well tolerated with low toxicity. Compared to historical data survival is significantly better with an additional SRT boost. However, its effectiveness has to be proven in a randomized trial
On varitional iteration method for fractional calculus
Directory of Open Access Journals (Sweden)
Wu Hai-Gen
2017-01-01
Full Text Available Modification of the Das’ variational iteration method for fractional differential equations is discussed, and its main shortcoming involved in the solution process is pointed out and overcome by using fractional power series. The suggested computational procedure is simple and reliable for fractional calculus.
Fractionation and identification of bioactive constituents from ...
African Journals Online (AJOL)
In view of antidiabetic and antioxidant properties observed in a previous study, crude ethanol leaf extract of Sapium ellipticum (SE) was fractionated using Silica gel F254 column chromatography to yield 164 fractions. Pooling together of fractions with similar thin layer chromatographic (TLC) mobility profile afforded five ...
dimensional generalised time-fractional Hirota equation
Indian Academy of Sciences (India)
Youwei Zhang
2018-02-09
Feb 9, 2018 ... tanh-expansion and complete discrimination system by means of fractional complex transform, travelling wave solutions are derived. ... Time-fractional Hirota equation; fractional complex transform; complete discrimination system; tanh- expansion ... Other applications in finance, physics and engineering ...
Early Predictors of Middle School Fraction Knowledge
Bailey, Drew H.; Siegler, Robert S.; Geary, David C.
2014-01-01
Recent findings that earlier fraction knowledge predicts later mathematics achievement raise the question of what predicts later fraction knowledge. Analyses of longitudinal data indicated that whole number magnitude knowledge in first grade predicted knowledge of fraction magnitudes in middle school, controlling for whole number arithmetic…
The Fractional Ornstein-Uhlenbeck Process
DEFF Research Database (Denmark)
Høg, Esben; Frederiksen, Per H.
of the standard Brownian motion. This is a new direction in pricing non defaultable bonds with offspring in the arbitrage free pricing of weather derivatives based on fractional Brownian motions. By applying fractional It^o calculus and a fractional version of the Girsanov transform, a no arbitrage price...
The Area Model of Multiplication of Fractions
Tsankova, Jenny K.; Pjanic, Karmen
2009-01-01
Teaching students how to multiply fractions is challenging, not so much from a computational point of view but from a conceptual one. The algorithm for multiplying fractions is much easier to learn than many other algorithms, such as subtraction with regrouping, long division, and certainly addition of fractions with unlike denominators. However,…
Few Fractional Order Derivatives and Their Computations
Bhatta, D. D.
2007-01-01
This work presents an introductory development of fractional order derivatives and their computations. Historical development of fractional calculus is discussed. This paper presents how to obtain computational results of fractional order derivatives for some elementary functions. Computational results are illustrated in tabular and graphical…
An Alternative Starting Point for Fraction Instruction
Cortina, José Luis; Višnovská, Jana; Zúñiga, Claudia
2015-01-01
We analyze the results of a study conducted for the purpose of assessing the viability of an alternative starting point for teaching fractions. The alternative is based on Freudenthal's insights about fraction as comparison. It involves portraying the entities that unit fractions quantify as always being apart from the reference unit, instead of…
Preparing for Algebra by Building Fraction Sense
Rodrigues, Jessica; Dyson, Nancy I.; Hansen, Nicole; Jordan, Nancy C.
2016-01-01
Fractions are troublesome for many children, especially students with learning difficulties and disabilities in mathematics. To address this serious educational concern, this article recommends the use of number lines to build fraction sense. Math activities that center on the number line build fraction concepts as early as third grade. A number…
Teaching Fractions. Educational Practices Series-22
Fazio, Lisa; Siegler, Robert
2011-01-01
Students around the world have difficulties in learning about fractions. In many countries, the average student never gains a conceptual knowledge of fractions. This research guide provides suggestions for teachers and administrators looking to improve fraction instruction in their classrooms or schools. The recommendations are based on a…
Local control after fractionated stereotactic radiation therapy for brain metastases.
Rajakesari, Selvan; Arvold, Nils D; Jimenez, Rachel B; Christianson, Laura W; Horvath, Margaret C; Claus, Elizabeth B; Golby, Alexandra J; Johnson, Mark D; Dunn, Ian F; Lee, Eudocia Q; Lin, Nancy U; Friesen, Scott; Mannarino, Edward G; Wagar, Matthew; Hacker, Fred L; Weiss, Stephanie E; Alexander, Brian M
2014-11-01
Stereotactic radiosurgery (SRS) is frequently used in the management of brain metastases, but concerns over potential toxicity limit applications for larger lesions or those in eloquent areas. Fractionated stereotactic radiation therapy (SRT) is often substituted for SRS in these cases. We retrospectively analyzed the efficacy and toxicity outcomes of patients who received SRT at our institution. Seventy patients with brain metastases treated with SRT from 2006-2012 were analyzed. The rates of local and distant intracranial progression, overall survival, acute toxicity, and radionecrosis were determined. The SRT regimen was 25 Gy in 5 fractions among 87 % of patients. The most common tumor histologies were non-small cell lung cancer (37 %), breast cancer (20 %) and melanoma (20 %), and the median tumor diameter was 1.7 cm (range 0.4-6.4 cm). Median survival after SRT was 10.7 months. Median time to local progression was 17 months, with a local control rate of 68 % at 6 months and 56 % at 1 year. Acute toxicity was seen in 11 patients (16 %), mostly grade 1 or 2 with the most common symptom being mild headache. Symptomatic radiation-induced treatment change was seen on follow-up MRIs in three patients (4.3 %). SRT appears to be a safe and reasonably effective technique to treat brain metastases deemed less suitable for SRS, though dose intensification strategies may further improve local control.
Grant, J P
1984-01-01
Growth monitoring charts, packets of oral rehydration salts (ORS), and vaccines, are inexpensive, life-saving, growth-protecting technologies which can enable parents to protect their children against the worst effects of poverty. Similarly, a matrix of current and easily understandable information about pregnancy, breast feeding, weaning, feeding during and immediately after illness, child spacing, and preparing and using home-made oral rehydration solutions, also could empower parents to protect the lives and the health of their children. The question arises as to how can these technologies and this information be put at the disposal of millions of families in the low-income world. The initial task of the Child Survival and Development Revolution is the communication of what is now possible, yet little is known about how to communicate information whose principal value is to the poor. There are 2 large-scale precedents: the Green Revolution, which in many instances succeeded in putting into the hands of thousands of small and large farmers the techniques and the knowledge which enabled them to double and treble the yields from their lands; and the campaign to put the knowledge and the means of family planning at the disposal of many millions of people. There are 2 lessons to be learned from these precedents: they have shown that the way to promote a people's technology and to put information at the disposal of the majority is by mobilizing all possible resources and working through all possible channels both to create the demand and to meet it; and neither the Green Revolution nor the family planning movement rally took off until they were viewed as political and economic priorities and given the full support of the nation's political leadership. Nowhere are these 2 lessons more clearly illustrated than in present-day Indonesia. Because the campaign for family planning was given high personal and political priority by the President, and because 85% of all family
Energy Technology Data Exchange (ETDEWEB)
Holsti, L.R. [Dept. of Radiotherapy and Oncology, Helsinki University Central Hospital (Finland); Pyrhoenen, S. [Dept. of Radiotherapy and Oncology, Helsinki University Central Hospital (Finland); Kajanti, M. [Dept. of Radiotherapy and Oncology, Helsinki University Central Hospital (Finland); Maentylae, M. [Dept. of Radiotherapy and Oncology, Helsinki University Central Hospital (Finland); Mattson, K. [Dept. of Internal Medicine, Div. of Pulmonary Medicine, Helsinki University Central Hospital (Finland); Maasilta, P. [Dept. of Internal Medicine, Div. of Pulmonary Medicine, Helsinki University Central Hospital (Finland); Kivisaari, L. [Dept. of Diagnostic Radiology, Helsinki University Central Hospital (Finland)
1997-09-01
Malignant pleural mesothelioma is a rare malignancy with a bleak prognosis. The role of radiotherapy has not yet been clarified. Our aim was to study the effect of altered fractionation on mesothelioma. We have treated 57 patients, 41 males and 16 females, with hemithorax irradiation with six different fractionation schedules. All the patients have been included in a combined modality program consisting of surgery followed by chemotherapy and finally by hemithorax irradiation. The radiotherapy schedules used were: I. Conventional fractionation of 20 Gy in 10 fractions over 12 days. II, Split-course radiotherapy 55 Gy in 25 fractions of 2.2 Gy over 7 weeks (a two weeks rest halfways) followed by a boost dose of 15 Gy over 8 days to the major tumour area. III. Hyperfractionation of 70 Gy over 7 weeks, 1.25 Gy BID with a 6-h interval and a 10-day rest halfways. IV. Combined hyperfractionation and hypofractionation, 35 Gy hyperfractionation in 28 fractions (1.25 Gy BID with a 6-h interval) over three weeks followed by 36 Gy hypofractionation 9 fractions of 4 Gy given every other day over 3 weeks to the major tumour areas only. V. Hypofractionation of 38.5 Gy over 15 days (9x3.5 Gy). VI. Combined conventional radiotherapy and hypofractionation with 20 Gy given conventionally in 10 fractions followed by 10 fractions of 3 Gy over two weeks, overall time 4 weeks. The 2-year survival rate of all patients was 21% and the 5-year survival rate 9%. Two patients are still alive more than 6 and 9 years after radiotherapy. Progression occurred after surgery in four patients, during and after chemotherapy in 22 patients and after completed radiotherapy in 29 patients. The pattern of progression was similar in each treatment group. (orig.).
International Nuclear Information System (INIS)
Tamura, Masaru; Inoue, Hiroshi; Kunimine, Hideo; Nakamura, Masaru; Ono, Nobuo; Zama, Akira; Ohye, Chihiro; Niibe, Hideo; Ishida, Yoichi
1988-01-01
Twenty-six adults with glioblastoma multiforme (grade 4 astrocytoma) were postoperatively given high-dose fractionated radiation therapy (5 Gy twice weekly) with Linac X-rays. The results were compared with those in 26 patients treated by conventional fractionated radiation therapy (2 Gy 5 times weekly). The survival rates following treatment with high-dose fractionated radiation therapy and conventional fractionated radiation therapy were 65 % vs. 65 % at 1 year, 31 % vs. 8 % at 2 years, 14 % vs. 4 % at 3 years, and 4 % vs. 0 % at 5 years. The difference in length of survival between the two treatment groups was not statistically significant (p = 0.423). Autopsies were performed on 11 patients given high-dose radiation therapy and 13 who received conventional irradiation. In the high-dose group one patient had no residual tumor (vs. none in the conventional group); four had small residual tumors (vs. three); one had extensive coagulative necrosis of the tumor and surrounding brain tissue (vs. four); four had proliferative tumor growth (vs. four); and one had mixed glioblastoma and fibrosarcoma (vs. two). Complete cure may be possible in some cases, if extensive tumor removal is feasible and is followed by high-dose fractionated radiation therapy. The biological effect appears to be much greater with high-dose than with conventional fractionated radiation therapy. Therefore, in cases of tumor recurrence, a second course of radiation therapy must be undertaken cautiously. (author)
Hamiltonian Chaos and Fractional Dynamics
International Nuclear Information System (INIS)
Combescure, M
2005-01-01
This book provides an introduction and discussion of the main issues in the current understanding of classical Hamiltonian chaos, and of its fractional space-time structure. It also develops the most complex and open problems in this context, and provides a set of possible applications of these notions to some fundamental questions of dynamics: complexity and entropy of systems, foundation of classical statistical physics on the basis of chaos theory, and so on. Starting with an introduction of the basic principles of the Hamiltonian theory of chaos, the book covers many topics that can be found elsewhere in the literature, but which are collected here for the readers' convenience. In the last three parts, the author develops topics which are not typically included in the standard textbooks; among them are: - the failure of the traditional description of chaotic dynamics in terms of diffusion equations; - he fractional kinematics, its foundation and renormalization group analysis; - 'pseudo-chaos', i.e. kinetics of systems with weak mixing and zero Lyapunov exponents; - directional complexity and entropy. The purpose of this book is to provide researchers and students in physics, mathematics and engineering with an overview of many aspects of chaos and fractality in Hamiltonian dynamical systems. In my opinion it achieves this aim, at least provided researchers and students (mainly those involved in mathematical physics) can complement this reading with comprehensive material from more specialized sources which are provided as references and 'further reading'. Each section contains introductory pedagogical material, often illustrated by figures coming from several numerical simulations which give the feeling of what's going on, and thus is very useful to the reader who is not very familiar with the topics presented. Some problems are included at the end of most sections to help the reader to go deeper into the subject. My one regret is that the book does not
Requirements Engineering for Survivable Systems. Networked Systems Survivability
National Research Council Canada - National Science Library
Mead, Nancy
2003-01-01
This report describes the current state of requirements engineering for survivable systems, that is, systems that are able to complete their mission in a timely manner, even if significant portions...
Second Study of Hyper-Fractionated Radiotherapy
Directory of Open Access Journals (Sweden)
R. Jacob
1999-01-01
Full Text Available Purpose and Method. Hyper-fractionated radiotherapy for treatment of soft tissue sarcomas is designed to deliver a higher total dose of radiation without an increase in late normal tissue damage. In a previous study at the Royal Marsden Hospital, a total dose of 75 Gy using twice daily 1.25 Gy fractions resulted in a higher incidence of late damage than conventional radiotherapy using 2 Gy daily fractions treating to a total of 60 Gy. The current trial therefore used a lower dose per fraction of 1.2 Gy and lower total dose of 72 Gy, with 60 fractions given over a period of 6 weeks.
Directory of Open Access Journals (Sweden)
Samuel M Shin
2015-09-01
Full Text Available Introduction: We expanded upon our previous experience using involved-field fractionated radiotherapy (IFRT as an alternative to whole brain radiotherapy (WBRT or stereotactic radiosurgery (SRS for patients with surgically resected brain metastases.Material and Methods: All patients with single brain metastases who underwent surgical resection followed by IFRT at our institution from 2006-2013 were evaluated. Local recurrence-free survival, distant failure-free survival and overall survival were determined. Analyses were performed associating clinical variables with local recurrence and distant failure. Salvage approaches and toxicity of treatment for each patient were also assessed.Results: Median follow-up was 19.1 months. Fifty-six patients were treated with a median dose of 40.05 Gy/15 fractions with IFRT to the resection cavity. Local recurrence-free survival was 91.4%, distant failure-free survival was 68.4%, and overall survival was 77.7% at 12 months. No variables were associated with increased local recurrence, however melanoma histopathology and infratentorial location were associated with distant failure on multivariate analysis. Local recurrences were salvaged in 5/8 patients, and distant failures were salvaged in 24/29 patients. Two patients developed radionecrosis.Conclusions: Adjuvant IFRT is feasible and safe for well-selected patients with surgically resected single brain metastases. Acceptable rates of local control and salvage of distal intracranial recurrences continue to be achieved with continued follow-up.
FIRST USE OF STEREOLOGY TO QUANTIFY THE SURVIVAL OF FAT AUTOGRAFTS
Directory of Open Access Journals (Sweden)
Eduardo Serna Cuéllar
2011-05-01
Full Text Available It is not usual to perform quantitative analyses on surgical materials. Rather, they are evaluated clinically, through qualitative methods, and if quantitation is done, it is on a 2-dimensional basis. In this study, the long-term survival of fat autografts (FAG in 40 subjects with facial soft tissue defects is quantified. An adipose tissue preparation from the abdomen obtained through liposuction and centrifugation is injected subcutaneously. Approximately 14 months later, the treated area is biopsied. Extensive computer-based histological analyses were performed using the stereological method in order to directly obtain three parameters: volume fraction of adipocytes in the fat tissue (VV, density (number per volume of adipocytes in the fat tissue (NV, and the mean cell volume of adipocytes (VA in each tissue sample. A set of equations based on these three quantitative parameters is produced for evaluation of the volumetric survival fraction (VSF of FAG. The presented data evidenced a 66% survival fraction at the 14-month follow-up. In routine practice, it would be sufficient to perform this volumetric analysis on the injected and biopsied fat samples to know what fraction of the FAG has survived. This is an objective method for quantifying FAG survival and will allow a standardized comparison between different research series and authors.
International Nuclear Information System (INIS)
Dasu, Alexandru; Denekamp, Juliana
1999-01-01
Purpose: A dose 'window of opportunity' has been identified in an earlier modeling study if the inducible repair variant of the LQ model is adopted instead of the pure LQ model, and if all survival curve parameters are equally modified by the presence or absence of oxygen. In this paper we have extended the calculations to consider survival curve parameters from 15 sets of data obtained for cells tested at low doses using clonogenic assays. Methods and Materials: A simple computer model has been used to simulate the response of each cell line to various doses per fraction in multifraction schedules, with oxic and hypoxic cells receiving the same fractional dose. We have then used pairs of simulated survival curves to estimate the effective hypoxic protection (OER') as a function of the dose per fraction. Results: The resistance of hypoxic cells is reduced by using smaller doses per fraction than 2 Gy in all these fractionated clinical simulations, whether using a simple LQ model, or the more complex LQ/IR model. If there is no inducible repair, the optimum dose is infinitely low. If there is inducible repair, there is an optimum dose per fraction at which hypoxic protection is minimized. This is usually around 0.5 Gy. It depends on the dose needed to induce repair being higher in hypoxia than in oxygen. The OER' may even go below unity, i.e. hypoxic cells may be more sensitive than oxic cells. Conclusions: If oxic and hypoxic cells are repeatedly exposed to doses of the same magnitude, as occurs in clinical radiotherapy, the observed hypoxic protection varies with the fractional dose. The OER' is predicted to diminish at lower doses in all cell lines. The loss of hypoxic resistance with superfractionation is predicted to be proportional to the capacity of the cells to induce repair, i.e. their intrinsic radioresistance at a dose of 2 Gy
Aircraft Survivability: Unmanned Aircraft Systems Survivability. Fall 2008
2008-01-01
airspace coordination, command and control, and reliability are driving UAS use and design. 25 JASP 2008 Survivability Short Courseby Dr. Mark Couch The...Mark Couch , Research Staff Member at the Institute for Defense Analyses. 27 Warfighters Need a Joint Survivability Libraryby Maj Trenton Alexander...best MAC conference in the past two years.” 1stLt James Stephenson, USAF, headed home in May 2008. During his tour, James did a great job
Role of radiotherapy fractionation in head and neck cancers (MARCH): an updated meta-analysis.
Lacas, Benjamin; Bourhis, Jean; Overgaard, Jens; Zhang, Qiang; Grégoire, Vincent; Nankivell, Matthew; Zackrisson, Björn; Szutkowski, Zbigniew; Suwiński, Rafał; Poulsen, Michael; O'Sullivan, Brian; Corvò, Renzo; Laskar, Sarbani Ghosh; Fallai, Carlo; Yamazaki, Hideya; Dobrowsky, Werner; Cho, Kwan Ho; Beadle, Beth; Langendijk, Johannes A; Viegas, Celia Maria Pais; Hay, John; Lotayef, Mohamed; Parmar, Mahesh K B; Aupérin, Anne; van Herpen, Carla; Maingon, Philippe; Trotti, Andy M; Grau, Cai; Pignon, Jean-Pierre; Blanchard, Pierre
2017-09-01
The Meta-Analysis of Radiotherapy in squamous cell Carcinomas of Head and neck (MARCH) showed that altered fractionation radiotherapy is associated with improved overall and progression-free survival compared with conventional radiotherapy, with hyperfractionated radiotherapy showing the greatest benefit. This update aims to confirm and explain the superiority of hyperfractionated radiotherapy over other altered fractionation radiotherapy regimens and to assess the benefit of altered fractionation within the context of concomitant chemotherapy with the inclusion of new trials. For this updated meta-analysis, we searched bibliography databases, trials registries, and meeting proceedings for published or unpublished randomised trials done between Jan 1, 2009, and July 15, 2015, comparing primary or postoperative conventional fractionation radiotherapy versus altered fractionation radiotherapy (comparison 1) or conventional fractionation radiotherapy plus concomitant chemotherapy versus altered fractionation radiotherapy alone (comparison 2). Eligible trials had to start randomisation on or after Jan 1, 1970, and completed accrual before Dec 31, 2010; had to have been randomised in a way that precluded prior knowledge of treatment assignment; and had to include patients with non-metastatic squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx undergoing first-line curative treatment. Trials including a non-conventional radiotherapy control group, investigating hypofractionated radiotherapy, or including mostly nasopharyngeal carcinomas were excluded. Trials were grouped in three types of altered fractionation: hyperfractionated, moderately accelerated, and very accelerated. Individual patient data were collected and combined with a fixed-effects model based on the intention-to-treat principle. The primary endpoint was overall survival. Comparison 1 (conventional fractionation radiotherapy vs altered fractionation radiotherapy) included 33
Cardiovascular disease incidence and survival
DEFF Research Database (Denmark)
Byberg, Stine; Agyemang, Charles; Zwisler, Ann-Dorthe
2016-01-01
Studies on cardiovascular disease (CVD) incidence and survival show varying results between different ethnic groups. Our aim was to add a new dimension by exploring the role of migrant status in combination with ethnic background on incidence of-and survival from-CVD and more specifically acute...... of some types of cardiovascular disease compared to Danish-born. Family-reunified migrants on the other hand had lower rates of CVD. All migrants had better survival than Danish-born indicating that migrants may not always be disadvantaged in health....
A shorter fractionation schedule for postlumpectomy breast cancer patients
International Nuclear Information System (INIS)
Shelley, Wendy; Brundage, Michael; Hayter, Charles; Paszat, Lawrence; Zhou, Sam; Mackillop, William
2000-01-01
Purpose: The purpose of this retrospective review was to determine the effectiveness of 40 Gy in 16 daily fractions in preventing local recurrence in postlumpectomy invasive breast cancer patients whose margins of resection were clear of tumor by at least 2 mm. Methods: Between September 1989 and December 1993, 294 breasts were treated with this regimen. The entire breast was treated, using a tangential parallel pair, with wedges as necessary, to a dose of 40 Gy in 16 daily fractions. No additional boost was given. The median duration of follow-up of surviving patients is 5.5 years. Recently, the patients' assessment of the cosmetic outcome of their treatment was obtained, using a mailed questionnaire. Results: The 5-year actuarial breast-relapse rate was 3.5%, with an overall 5-year survival and disease-specific survival of 87.8% and 92.1%, respectively. In response to the cosmesis questionnaire, 77% of patients stated they were either extremely or very satisfied with the overall appearance of the breast, 19.5% moderately satisfied, and 3.5% either slightly or not at all satisfied. The corresponding responses for overall level of comfort of the breast were 79%, 16.5%, and 4.5% respectively. Conclusion: This regimen is very effective at preventing recurrent breast cancer in this group of patients, and it provides a high level of patient satisfaction with cosmetic outcome. Its short duration offers the added advantage of a more efficient use of resources and greater patient convenience
Effects of genistein following fractionated lung irradiation in mice
International Nuclear Information System (INIS)
Para, Andrea E.; Bezjak, Andrea; Yeung, Ivan W.T.; Van Dyk, Jake; Hill, Richard P.
2009-01-01
Background and purpose: This study investigated protection of lung injury by genistein following fractionated doses of radiation and its effect on tumor response. Material and methods: C3H/HeJ mice were irradiated (100 kVp X-rays) with 9 fractions of 3.1 Gy over 30 days (approximately equivalent to 10 Gy single dose) and were maintained on a genistein diet (∼10 mg/kg). Damage was assessed over 28 weeks in lung cells by a cytokinesis block micronucleus (MN) assay and by changes in breathing rate and histology. Tumor protection was assessed using a colony assay to determine cell survival following in situ irradiation of small lung nodules (KHT fibrosarcoma). Results: Genistein caused about a 50% reduction in the MN damage observed during the fractionated radiation treatment and this damage continued to decrease at later times to background levels by 16 weeks. In mice not receiving Genistein MN levels remained well above background out to 28 weeks after irradiation. Genistein reduced macrophage accumulation by 22% and reduced collagen deposition by 28%. There was minimal protection against increases in breathing rate or severe morbidity during pneumonitis. No tumor protection by genistein treatment was observed. Conclusions: Genistein at the dose levels used in this study partially reduced the extent of fibrosis developing in mouse lung caused by irradiation but gave minimal protection against pneumonitis. There was no evidence that genistein caused protection of small tumors growing in the lung.
Directory of Open Access Journals (Sweden)
Ai-Min Yang
2014-01-01
Full Text Available The local fractional Laplace variational iteration method was applied to solve the linear local fractional partial differential equations. The local fractional Laplace variational iteration method is coupled by the local fractional variational iteration method and Laplace transform. The nondifferentiable approximate solutions are obtained and their graphs are also shown.
Salk, Jonas
1975-01-01
Suggests that humans differ from other living organisms in the ability to exercise learned behavior and the individual will, which may allow people to make the changes in values necessary to survive on this planet. (DW)
Probabilistic Survivability Versus Time Modeling
Joyner, James J., Sr.
2016-01-01
This presentation documents Kennedy Space Center's Independent Assessment work completed on three assessments for the Ground Systems Development and Operations (GSDO) Program to assist the Chief Safety and Mission Assurance Officer during key programmatic reviews and provided the GSDO Program with analyses of how egress time affects the likelihood of astronaut and ground worker survival during an emergency. For each assessment, a team developed probability distributions for hazard scenarios to address statistical uncertainty, resulting in survivability plots over time. The first assessment developed a mathematical model of probabilistic survivability versus time to reach a safe location using an ideal Emergency Egress System at Launch Complex 39B (LC-39B); the second used the first model to evaluate and compare various egress systems under consideration at LC-39B. The third used a modified LC-39B model to determine if a specific hazard decreased survivability more rapidly than other events during flight hardware processing in Kennedy's Vehicle Assembly Building.
Customer service skills for survival.
McAtee, L F
1999-11-01
As APICS practitioners, we all must share a common goal. How can we contribute to our company's success? Success can be measured in positive terms of market share, growth, profitability, return on investment, or some combination thereof. Each company must establish its own definition of success. For the purposes of this article, success will be equated to one word that we can all readily identify with: survival. What skills do we need to survive in the marketplace of the next millennium?
Filippo Randelli; Giorgio Ricchiuti
2015-01-01
In this paper we analyze the survival probability of firms in Tuscany (Italy) in the first decade of the $21^{st}$ century. Using the Official Register of Firms, held by Unioncamere Toscany, we build a panel for the period 1998-2010. Taking into account both individual and context variables, we find that a higher institutional complexity and a lower population density have a positive and significant effect on probability to survive. Moreover, both MAR and Jacob externalities have a nonlinear ...
Interdisciplinary ICU cardiac arrest debriefing improves survival outcomes*.
Wolfe, Heather; Zebuhr, Carleen; Topjian, Alexis A; Nishisaki, Akira; Niles, Dana E; Meaney, Peter A; Boyle, Lori; Giordano, Rita T; Davis, Daniela; Priestley, Margaret; Apkon, Michael; Berg, Robert A; Nadkarni, Vinay M; Sutton, Robert M
2014-07-01
In-hospital cardiac arrest is an important public health problem. High-quality resuscitation improves survival but is difficult to achieve. Our objective is to evaluate the effectiveness of a novel, interdisciplinary, postevent quantitative debriefing program to improve survival outcomes after in-hospital pediatric chest compression events. Single-center prospective interventional study of children who received chest compressions between December 2008 and June 2012 in the ICU. Structured, quantitative, audiovisual, interdisciplinary debriefing of chest compression events with front-line providers. Primary outcome was survival to hospital discharge. Secondary outcomes included survival of event (return of spontaneous circulation for ≥ 20 min) and favorable neurologic outcome. Primary resuscitation quality outcome was a composite variable, termed "excellent cardiopulmonary resuscitation," prospectively defined as a chest compression depth ≥ 38 mm, rate ≥ 100/min, ≤ 10% of chest compressions with leaning, and a chest compression fraction > 90% during a given 30-second epoch. Quantitative data were available only for patients who are 8 years old or older. There were 119 chest compression events (60 control and 59 interventional). The intervention was associated with a trend toward improved survival to hospital discharge on both univariate analysis (52% vs 33%, p = 0.054) and after controlling for confounders (adjusted odds ratio, 2.5; 95% CI, 0.91-6.8; p = 0.075), and it significantly increased survival with favorable neurologic outcome on both univariate (50% vs 29%, p = 0.036) and multivariable analyses (adjusted odds ratio, 2.75; 95% CI, 1.01-7.5; p = 0.047). Cardiopulmonary resuscitation epochs for patients who are 8 years old or older during the debriefing period were 5.6 times more likely to meet targets of excellent cardiopulmonary resuscitation (95% CI, 2.9-10.6; p < 0.01). Implementation of an interdisciplinary, postevent quantitative debriefing
Micrograft size and subsequent survival.
Seager, D J
1997-09-01
Micrograft survival rates in hair transplantation have been frequently described in private conversations by hair transplant doctors as variable at best. References in medical literature may grossly underestimate the prevalence and magnitude of poor growth. This is probably because most hair transplant surgeons are concerned that publication of a significant incidence of poor growth would reflect negatively on their practice. The purpose of this research was to study micrograft survival rates using microscopic dissection techniques. The author also presents a hypothesis regarding the relatively poor survival rates reported by hair transplant physicians. Two different groups of micrografts were prepared. One group, mainly single-haired with tissue trimmed close to the hair shaft, was planted into one test patch in the bald crown of a patient's scalp. Another group of intact follicular clumps, prepared with more dermis, subcutaneous fat, and intact sebaceous glands, was planted into another test patch. These test patches and their growth were documented with close-up photography. The micrografts prepared as existing follicular clumps had a much higher survival rate (over 100%) than the micrografts cut as slender single hairs. Extremely high survival rates of micrografts are obtainable by transplanting intact follicular clumps with protective tissue around the micrograft, and preserving the follicular clump's sebaceous gland. These survival rates were not achieved when micrografts were produced by splitting individual hairs away from a naturally occurring follicular clump.
Fractions Learning in Children With Mathematics Difficulties.
Tian, Jing; Siegler, Robert S
Learning fractions is difficult for children in general and especially difficult for children with mathematics difficulties (MD). Recent research on developmental and individual differences in fraction knowledge of children with MD and typically achieving (TA) children has demonstrated that U.S. children with MD start middle school behind their TA peers in fraction understanding and fall further behind during middle school. In contrast, Chinese children, who like the MD children in the United States score in the bottom one third of the distribution in their country, possess reasonably good fraction understanding. We interpret these findings within the framework of the integrated theory of numerical development. By emphasizing the importance of fraction magnitude knowledge for numerical understanding in general, the theory proved useful for understanding differences in fraction knowledge between MD and TA children and for understanding how knowledge can be improved. Several interventions demonstrated the possibility of improving fraction magnitude knowledge and producing benefits that generalize to fraction arithmetic learning among children with MD. The reasonably good fraction understanding of Chinese children with MD and several successful interventions with U.S. students provide hope for the improvement of fraction knowledge among American children with MD.
The Initial Conditions of Fractional Calculus
International Nuclear Information System (INIS)
Trigeassou, J. C.; Maamri, N.
2011-01-01
During the past fifty years , Fractional Calculus has become an original and renowned mathematical tool for the modelling of diffusion Partial Differential Equations and the design of robust control algorithms. However, in spite of these celebrated results, some theoretical problems have not yet received a satisfying solution. The mastery of initial conditions, either for Fractional Differential Equations (FDEs) or for the Caputo and Riemann-Liouville fractional derivatives, remains an open research domain. The solution of this fundamental problem, also related to the long range memory property, is certainly the necessary prerequisite for a satisfying approach to modelling and control applications. The fractional integrator and its continuously frequency distributed differential model is a valuable tool for the simulation of fractional systems and the solution of initial condition problems. Indeed, the infinite dimensional state vector of fractional integrators allows the direct generalization to fractional calculus of the theoretical results of integer order systems. After a reminder of definitions and properties related to fractional derivatives and systems, this presentation is intended to show, based on the results of two recent publications [1,2], how the fractional integrator provides the solution of the initial condition problem of FDEs and of Caputo and Riemann-Liouville fractional derivatives. Numerical simulation examples illustrate and validate these new theoretical concepts.
Survival analysis of heart failure patients: A case study.
Directory of Open Access Journals (Sweden)
Tanvir Ahmad
Full Text Available This study was focused on survival analysis of heart failure patients who were admitted to Institute of Cardiology and Allied hospital Faisalabad-Pakistan during April-December (2015. All the patients were aged 40 years or above, having left ventricular systolic dysfunction, belonging to NYHA class III and IV. Cox regression was used to model mortality considering age, ejection fraction, serum creatinine, serum sodium, anemia, platelets, creatinine phosphokinase, blood pressure, gender, diabetes and smoking status as potentially contributing for mortality. Kaplan Meier plot was used to study the general pattern of survival which showed high intensity of mortality in the initial days and then a gradual increase up to the end of study. Martingale residuals were used to assess functional form of variables. Results were validated computing calibration slope and discrimination ability of model via bootstrapping. For graphical prediction of survival probability, a nomogram was constructed. Age, renal dysfunction, blood pressure, ejection fraction and anemia were found as significant risk factors for mortality among heart failure patients.
Fractional ablative erbium YAG laser
DEFF Research Database (Denmark)
Taudorf, Elisabeth H; Haak, Christina S; Erlendsson, Andrés M
2014-01-01
BACKGROUND AND OBJECTIVES: Treatment of a variety of skin disorders with ablative fractional lasers (AFXL) is driving the development of portable AFXLs. This study measures micropore dimensions produced by a small 2,940 nm AFXL using a variety of stacked pulses, and determines a model correlating...... laser parameters with tissue effects. MATERIALS AND METHODS: Ex vivo pig skin was exposed to a miniaturized 2,940 nm AFXL, spot size 225 µm, density 5%, power levels 1.15-2.22 W, pulse durations 50-225 microseconds, pulse repetition rates 100-500 Hz, and 2, 20, or 50 stacked pulses, resulting in pulse...... 190 to 347 µm. CONCLUSIONS: Pulse stacking with a small, low power 2,940 nm AFXL created reproducible shallow to deep micropores, and influenced micropore configuration. Mathematical modeling established relations between laser settings and micropore dimensions, which assists in choosing laser...
The fractional oscillator process with two indices
International Nuclear Information System (INIS)
Lim, S C; Teo, L P
2009-01-01
We introduce a new fractional oscillator process which can be obtained as a solution of a stochastic differential equation with two fractional orders. Basic properties such as fractal dimension and short-range dependence of the process are studied by considering the asymptotic properties of its covariance function. By considering the fractional oscillator process as the velocity of a diffusion process, we derive the corresponding diffusion constant, fluctuation-dissipation relation and mean-square displacement. The fractional oscillator process can also be regarded as a one-dimensional fractional Euclidean Klein-Gordon field, which can be obtained by applying the Parisi-Wu stochastic quantization method to a nonlocal Euclidean action. The Casimir energy associated with the fractional field at positive temperature is calculated by using the zeta function regularization technique
Probabilistic Survivability Versus Time Modeling
Joyner, James J., Sr.
2015-01-01
This technical paper documents Kennedy Space Centers Independent Assessment team work completed on three assessments for the Ground Systems Development and Operations (GSDO) Program to assist the Chief Safety and Mission Assurance Officer (CSO) and GSDO management during key programmatic reviews. The assessments provided the GSDO Program with an analysis of how egress time affects the likelihood of astronaut and worker survival during an emergency. For each assessment, the team developed probability distributions for hazard scenarios to address statistical uncertainty, resulting in survivability plots over time. The first assessment developed a mathematical model of probabilistic survivability versus time to reach a safe location using an ideal Emergency Egress System at Launch Complex 39B (LC-39B); the second used the first model to evaluate and compare various egress systems under consideration at LC-39B. The third used a modified LC-39B model to determine if a specific hazard decreased survivability more rapidly than other events during flight hardware processing in Kennedys Vehicle Assembly Building (VAB).Based on the composite survivability versus time graphs from the first two assessments, there was a soft knee in the Figure of Merit graphs at eight minutes (ten minutes after egress ordered). Thus, the graphs illustrated to the decision makers that the final emergency egress design selected should have the capability of transporting the flight crew from the top of LC 39B to a safe location in eight minutes or less. Results for the third assessment were dominated by hazards that were classified as instantaneous in nature (e.g. stacking mishaps) and therefore had no effect on survivability vs time to egress the VAB. VAB emergency scenarios that degraded over time (e.g. fire) produced survivability vs time graphs that were line with aerospace industry norms.
Operator Fractional Brownian Motion and Martingale Differences
Directory of Open Access Journals (Sweden)
Hongshuai Dai
2014-01-01
Full Text Available It is well known that martingale difference sequences are very useful in applications and theory. On the other hand, the operator fractional Brownian motion as an extension of the well-known fractional Brownian motion also plays an important role in both applications and theory. In this paper, we study the relation between them. We construct an approximation sequence of operator fractional Brownian motion based on a martingale difference sequence.
On some fractional order hardy inequalities
Directory of Open Access Journals (Sweden)
Lars-Erik Persson
1997-01-01
Full Text Available Weighted inequalities for fractional derivatives (= fractional order Hardy-type inequalities have recently been proved in [4] and [1]. In this paper, new inequalities of this type are proved and applied. In particular, the general mixed norm case and a general twodimensional weight are considered. Moreover, an Orlicz norm version and a multidimensional fractional order Hardy inequality are proved. The connections to related results are pointed out.
On some fractional order hardy inequalities
Directory of Open Access Journals (Sweden)
Kufner Alois
1997-01-01
Full Text Available Weighted inequalities for fractional derivatives ( fractional order Hardy-type inequalities have recently been proved in [4] and [1]. In this paper, new inequalities of this type are proved and applied. In particular, the general mixed norm case and a general twodimensional weight are considered. Moreover, an Orlicz norm version and a multidimensional fractional order Hardy inequality are proved. The connections to related results are pointed out.
Early Predictors of Middle School Fraction Knowledge
Bailey, Drew H.; Siegler, Robert S.; Geary, David C.
2014-01-01
Recent findings that earlier fraction knowledge predicts later mathematics achievement raise the question of what predicts later fraction knowledge. Analyses of longitudinal data indicated that whole number magnitude knowledge in first grade predicted knowledge of fraction magnitudes in middle school, controlling for whole number arithmetic proficiency, domain general cognitive abilities, parental income and education, race, and gender. Similarly, knowledge of whole number arithmetic in first...
Fractional Differential and Integral Inequalities with Applications
2016-02-14
boundary conditions. References [1] D. Baleanu, Z. B. Guvencs̈ , J.A. T. Machado, New Trends in Nanotechnology and Fractional Calculus Applications ...Rivero, J. Trujillo and M. Pilar Velasco, “On Deterministic Fractional Models,” New Trends in Nanotechnology and Fractional Calculus Applications , edited...coupled minimal and maximal solutions for such an equation and a numerical example is provided as an application of the theoretical results. The
Field-flow fractionation of chromosomes
Energy Technology Data Exchange (ETDEWEB)
Giddings, J.C.
1990-09-01
Research continued on field flow fractionation of chromosomes. Progress in the past year can be organized into three main categories: (1) chromosome sample preparation; (2) preliminary chromosome fractionation; (3) fractionation of a polystyrene aggregate model which approximates the chromosome shape. We have been successful in isolating metaphase chromosomes from the Chinese hamster. We also received a human chromosome sample from Dr. Carolyn Bell-Prince of Los Alamos National Laboratory. Results are discussed. 2 figs.
Fractional Calculus in Wave Propagation Problems
Mainardi, Francesco
2012-01-01
Fractional calculus, in allowing integrals and derivatives of any positive order (the term "fractional" kept only for historical reasons), can be considered a branch of mathematical physics which mainly deals with integro-differential equations, where integrals are of convolution form with weakly singular kernels of power law type. In recent decades fractional calculus has won more and more interest in applications in several fields of applied sciences. In this lecture we devote our attention...
Unpacking the Division Interpretation of a Fraction
Poon, Rebecca C.; Lewis, Priscilla Eide
2015-01-01
One of the challenges in learning fractions is understanding how and why a fraction can have multiple interpretations. As presented in one textbook, a fraction is "a symbol, such as 2/3, 5/1, or 8/5, used to name a part of a whole, a part of a set, a location on a number line, or a division of whole numbers" (Charles et al. 2012, p.…
Control of Initialized Fractional-Order Systems
Hartly, Tom T.; Lorenzo, Carl F.
2002-01-01
Due to the importance of historical effects in fractional-order systems, this paper presents a general fractional-order control theory that includes the time-varying initialization response. Previous studies have not properly accounted for these historical effects. The initialization response, along with the forced response, for fractional-order systems is determined. Stability properties of fractional-order systems are presented in the complex Airplane, which is a transformation of the s-plane. Time responses are discussed with respect to pole positions in the complex Airplane and frequency response behavior is included. A fractional-order vector space representation, which is a generalization of the state space concept, is presented including the initialization response. Control methods for vector representations of initialized fractional-order systems are shown. Nyquist, root-locus, and other input-output control methods are adapted to the control of fractional-order systems. Finally, the fractional-order differintegral is generalized to continuous order-distributions that have the possibility of including a continuum of fractional orders in a system element.
Vector continued fractions using a generalized inverse
International Nuclear Information System (INIS)
Haydock, Roger; Nex, C M M; Wexler, Geoffrey
2004-01-01
A real vector space combined with an inverse (involution) for vectors is sufficient to define a vector continued fraction whose parameters consist of vector shifts and changes of scale. The choice of sign for different components of the vector inverse permits construction of vector analogues of the Jacobi continued fraction. These vector Jacobi fractions are related to vector and scalar-valued polynomial functions of the vectors, which satisfy recurrence relations similar to those of orthogonal polynomials. The vector Jacobi fraction has strong convergence properties which are demonstrated analytically, and illustrated numerically
Oxygen isotope fractionation in double carbonates.
Zheng, Yong-Fei; Böttcher, Michael E
2016-01-01
Oxygen isotope fractionations in double carbonates of different crystal structures were calculated by the increment method. Synthesis experiments were performed at 60 °C and 100 °C to determine oxygen and carbon isotope fractionations involving PbMg[CO3]2. The calculations suggest that the double carbonates of calcite structure are systematically enriched in (18)O relative to those of aragonite and mixture structures. Internally consistent oxygen isotope fractionation factors are obtained for these minerals with respect to quartz, calcite and water at a temperature range of 0-1200 °C. The calculated fractionation factors for double carbonate-water systems are generally consistent with the data available from laboratory experiments. The experimentally determined fractionation factors for PbMg[CO3]2, BaMg[CO3]2 and CaMg[CO3]2 against H2O not only fall between fractionation factors involving pure carbonate end-members but are also close to the calculated fractionation factors. In contrast, experimentally determined carbon isotope fractionation factors between PbMg[CO3]2 and CO2 are much closer to theoretical predictions for the cerussite-CO2 system than for the magnesite-CO2 system, similar to the fractionation behavior for BaMg[CO3]2. Therefore, the combined theoretical and experimental results provide insights into the effects of crystal structure and exchange kinetics on oxygen isotope partitioning in double carbonates.
Easy characterization of petroleum fractions: Part 1
Energy Technology Data Exchange (ETDEWEB)
Miquel, J. (Univ. Politecnica de Catalunya (Spain)); Castells, F. (Univ. Rovira i Virgili, Catalunya (Spain))
1993-12-01
A new method for characterizing petroleum fractions, based on pseudocomponent breakdown using the integral method has been developed. It requires only that one has an atmospheric true boiling point (tbp) distillation curve and known the entire fraction density. The proposed characterization procedure is valid for representing any oil fraction (light or heavy) with a boiling point range smaller than 300 K. It is based on the hypothesis of constant Watson's characterization factor, K[sub w], for all the pseudocomponents. Outside this range, it is less accurate (greater errors in material and molar balances). Therefore, a method considering the variable K[sub w] is best to treat these fractions.
Improving Children's Knowledge of Fraction Magnitudes.
Directory of Open Access Journals (Sweden)
Lisa K Fazio
Full Text Available We examined whether playing a computerized fraction game, based on the integrated theory of numerical development and on the Common Core State Standards' suggestions for teaching fractions, would improve children's fraction magnitude understanding. Fourth and fifth-graders were given brief instruction about unit fractions and played Catch the Monster with Fractions, a game in which they estimated fraction locations on a number line and received feedback on the accuracy of their estimates. The intervention lasted less than 15 minutes. In our initial study, children showed large gains from pretest to posttest in their fraction number line estimates, magnitude comparisons, and recall accuracy. In a more rigorous second study, the experimental group showed similarly large improvements, whereas a control group showed no improvement from practicing fraction number line estimates without feedback. The results provide evidence for the effectiveness of interventions emphasizing fraction magnitudes and indicate how psychological theories and research can be used to evaluate specific recommendations of the Common Core State Standards.
Theory and applications of fractional differential equations
Kilbas, Anatoly A; Trujillo, Juan J; Van Mill, Jan
2006-01-01
This monograph provides the most recent and up-to-date developments on fractional differential and fractional integro-differential equations involving many different potentially useful operators of fractional calculus. The subject of fractional calculus and its applications (that is, calculus of integrals and derivatives of any arbitrary real or complex order) has gained considerable popularity and importance during the past three decades or so, due mainly to its demonstrated applications in numerous seemingly diverse and widespread fields of science and engineering. Some of the areas of prese
DYNAMICS OF FRACTIONAL ORDER CHAOTIC SYSTEM
Directory of Open Access Journals (Sweden)
M. Jana
2017-02-01
Full Text Available This paper deals with the dynamics of chaos and synchronization for fractional order chaotic system. For fractional order derivative Captuo definition is used here and numerical simulations are done using Predictor-Correctors scheme by Diethlm based on the Adams-Baseforth-Moulton algorithm. Stability analysis is discussed here for non linear fractional order chaotic system and synchronization is achieved between two non identical fractional order chaotic systems: Finance chaotic system(driving systemand Lorenz system(response systemvia active control.Numerical simulations are performed to show the effectiveness of these approaches.
Model selection for univariable fractional polynomials.
Royston, Patrick
2017-07-01
Since Royston and Altman's 1994 publication ( Journal of the Royal Statistical Society, Series C 43: 429-467), fractional polynomials have steadily gained popularity as a tool for flexible parametric modeling of regression relationships. In this article, I present fp_select, a postestimation tool for fp that allows the user to select a parsimonious fractional polynomial model according to a closed test procedure called the fractional polynomial selection procedure or function selection procedure. I also give a brief introduction to fractional polynomial models and provide examples of using fp and fp_select to select such models with real data.
Maximum likelihood estimation of fractionally cointegrated systems
DEFF Research Database (Denmark)
Lasak, Katarzyna
In this paper we consider a fractionally cointegrated error correction model and investigate asymptotic properties of the maximum likelihood (ML) estimators of the matrix of the cointe- gration relations, the degree of fractional cointegration, the matrix of the speed of adjustment to the equilib......In this paper we consider a fractionally cointegrated error correction model and investigate asymptotic properties of the maximum likelihood (ML) estimators of the matrix of the cointe- gration relations, the degree of fractional cointegration, the matrix of the speed of adjustment...
In Vitro and In Vivo Anticancer Effects of Sterol Fraction from Red Algae Porphyra dentata
Kazłowska, Katarzyna; Lin, Hong-Ting Victor; Chang, Shun-Hsien
2013-01-01
Porphyra dentata, an edible red macroalgae, is used as a folk medicine in Asia. This study evaluated in vitro and in vivo the protective effect of a sterol fraction from P. dentata against breast cancer linked to tumor-induced myeloid derived-suppressor cells (MDSCs). A sterol fraction containing cholesterol, β-sitosterol, and campesterol was prepared by solvent fractionation of methanol extract of P. dentata in silica gel column chromatography. This sterol fraction in vitro significantly inhibited cell growth and induced apoptosis in 4T1 cancer cells. Intraperitoneal injection of this sterol fraction at 10 and 25 mg/kg body weight into 4T1 cell-implanted tumor BALB/c mice significantly inhibited the growth of tumor nodules and increased the survival rate of mice. This sterol fraction significantly decreased the reactive oxygen species (ROS) and arginase activity of MDSCs in tumor-bearing mice. Therefore, the sterol fraction from P. dentata showed potential for protecting an organism from 4T1 cell-based tumor genesis. PMID:24062783
In Vitro and In Vivo Anticancer Effects of Sterol Fraction from Red Algae Porphyra dentata
Directory of Open Access Journals (Sweden)
Katarzyna Kazłowska
2013-01-01
Full Text Available Porphyra dentata, an edible red macroalgae, is used as a folk medicine in Asia. This study evaluated in vitro and in vivo the protective effect of a sterol fraction from P. dentata against breast cancer linked to tumor-induced myeloid derived-suppressor cells (MDSCs. A sterol fraction containing cholesterol, β-sitosterol, and campesterol was prepared by solvent fractionation of methanol extract of P. dentata in silica gel column chromatography. This sterol fraction in vitro significantly inhibited cell growth and induced apoptosis in 4T1 cancer cells. Intraperitoneal injection of this sterol fraction at 10 and 25 mg/kg body weight into 4T1 cell-implanted tumor BALB/c mice significantly inhibited the growth of tumor nodules and increased the survival rate of mice. This sterol fraction significantly decreased the reactive oxygen species (ROS and arginase activity of MDSCs in tumor-bearing mice. Therefore, the sterol fraction from P. dentata showed potential for protecting an organism from 4T1 cell-based tumor genesis.
Directory of Open Access Journals (Sweden)
Greenspoon JN
2014-03-01
Full Text Available Jeffrey Noah Greenspoon,1 Waseem Sharieff,1 Holger Hirte,1 Andrew Overholt,1 Rocco Devillers,2 Thorsteinn Gunnarsson,2 Anthony Whitton11Department of Oncology, McMaster University, ON, Canada; 2Department of Surgery, McMaster University, ON, CanadaAbstract: Local recurrence represents a significant challenge in the management of patients with glioblastoma multiforme. Salvage treatment options are limited by lack of clinical efficacy. Recent studies have demonstrated a significant response rate and acceptable toxicity with the use of fractionated stereotactic radiosurgery in this patient population. Our primary objective was to determine the efficacy and toxicity of fractionated stereotactic radiosurgery combined with concurrent temozolomide chemotherapy as a salvage treatment for recurrent glioblastoma multiforme. We prospectively collected treatment and outcome data for patients having fractionated stereotactic radiosurgery for locally recurrent glioblastoma multiforme after radical radiotherapy. Eligible patients had a maximum recurrence diameter of 60 mm without causing significant mass effect. The gross tumor volume was defined as the enhancing lesion on an enhanced fine-slice T1 (spin–lattice magnetic resonance imaging, and a circumferential setup margin of 1 mm was used to define the planning target volume. All patients were treated using robotic radiosurgery with three dose/fractionation schedules ranging from 25 to 35 Gy in five fractions, depending on the maximum tumor diameter. Concurrent temozolomide 75 mg/m2 was prescribed to all patients. Tumor response was judged using the Macdonald criteria, and toxicity was assessed using the CTCAE (Common Terminology Criteria for Adverse Events. A total of 31 patients were enrolled in this study. The median overall survival was 9 months, and progression-free survival was 7 months. The 6-month progression-free survival was 60% with a 95% confidence interval of 43%–77%. The a priori
Agile Objects: Component-Based Inherent Survivability
National Research Council Canada - National Science Library
Chien, Andrew
2003-01-01
We have developed a framework called Agile Objects which leverages component object models and enables the construction of survivable systems that support increased application survivability through elusive technologies...
Directory of Open Access Journals (Sweden)
Yi-Fei Pu
2013-01-01
Full Text Available The traditional integer-order partial differential equation-based image denoising approaches often blur the edge and complex texture detail; thus, their denoising effects for texture image are not very good. To solve the problem, a fractional partial differential equation-based denoising model for texture image is proposed, which applies a novel mathematical method—fractional calculus to image processing from the view of system evolution. We know from previous studies that fractional-order calculus has some unique properties comparing to integer-order differential calculus that it can nonlinearly enhance complex texture detail during the digital image processing. The goal of the proposed model is to overcome the problems mentioned above by using the properties of fractional differential calculus. It extended traditional integer-order equation to a fractional order and proposed the fractional Green’s formula and the fractional Euler-Lagrange formula for two-dimensional image processing, and then a fractional partial differential equation based denoising model was proposed. The experimental results prove that the abilities of the proposed denoising model to preserve the high-frequency edge and complex texture information are obviously superior to those of traditional integral based algorithms, especially for texture detail rich images.
Fractional-order adaptive fault estimation for a class of nonlinear fractional-order systems
N'Doye, Ibrahima
2015-07-01
This paper studies the problem of fractional-order adaptive fault estimation for a class of fractional-order Lipschitz nonlinear systems using fractional-order adaptive fault observer. Sufficient conditions for the asymptotical convergence of the fractional-order state estimation error, the conventional integer-order and the fractional-order faults estimation error are derived in terms of linear matrix inequalities (LMIs) formulation by introducing a continuous frequency distributed equivalent model and using an indirect Lyapunov approach where the fractional-order α belongs to 0 < α < 1. A numerical example is given to demonstrate the validity of the proposed approach.
Late course accelerated fractionation in radiotherapy of esophageal carcinoma
International Nuclear Information System (INIS)
Shi, X.-H.; Yao, W.; Liu, T.
1999-01-01
Purpose: To evaluate the efficacy of adding accelerated fractionation after completing two thirds of routine fractionated radiotherapy in esophageal carcinoma.Methods and materials: From April 1988 to April 1990, 85 patients with histologically confirmed carcinoma of the esophagus were randomized into two groups. (1) The conventional fractionation (CF) group, received 1.8 Gy per day five times a week to a total dose of 68.4 Gy in 7-8 weeks, and (2) the late course accelerated hyperfractionated (LCAF) group which received the same schedule as the CF group during the first two thirds of the course of radiotherapy to a dose of 41.4 Gy/23 fx/4 to 5 weeks. This was then followed by accelerated hyperfractionation using reduced fields. In the LCAF portion of the radiotherapeutic course, the irradiation schedule was changed to 1.5 Gy twice a day, with an interval of 4 h between fractions, to a dose of 27 Gy/18 fx. Thus the total dose was also 68.4 Gy, the same as the CF group, but the course of radiotherapy was shorter, being only 6.4 weeks. The same Cobalt 60 teletherapy unit was used to treat all the cases.Results: The 5 year actuarial survival and disease-free survival rates in the LCAF group were 34% and 42%, as compared to 15% and 15% respectively in the CF group, all statistically significant. Better local control was seen in the LCAF group than in the CF group, the 5 year control rates being 55% versus 21% (P=0.003). The acute reactions were increased but acceptable in the LCAF patients, the radiation treatments could be completed without any breaks. The late reactions as observed after 5 years were not increased in comparison with the CF patients.Conclusions: The results from this study show that the late course accelerated hyperfractionated radiotherapy regime can improve results in esophageal carcinoma, with acceptable acute reactions as compared to conventional radiotherapy. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)
Cell Survival Signaling in Neuroblastoma
Megison, Michael L.; Gillory, Lauren A.; Beierle, Elizabeth A.
2013-01-01
Neuroblastoma is the most common extracranial solid tumor of childhood and is responsible for over 15% of pediatric cancer deaths. Neuroblastoma tumorigenesis and malignant transformation is driven by overexpression and dominance of cell survival pathways and a lack of normal cellular senescence or apoptosis. Therefore, manipulation of cell survival pathways may decrease the malignant potential of these tumors and provide avenues for the development of novel therapeutics. This review focuses on several facets of cell survival pathways including protein kinases (PI3K, AKT, ALK, and FAK), transcription factors (NF-κB, MYCN and p53), and growth factors (IGF, EGF, PDGF, and VEGF). Modulation of each of these factors decreases the growth or otherwise hinders the malignant potential of neuroblastoma, and many therapeutics targeting these pathways are already in the clinical trial phase of development. Continued research and discovery of effective modulators of these pathways will revolutionize the treatment of neuroblastoma. PMID:22934706
Adaptive response and split-dose effect of radiation on the survival ...
Indian Academy of Sciences (India)
These results clearly showed the occurrence of adaptive response in terms of survival of animals. The conditioning dose given in small fractions seemed to be more effective. The findings have been discussed from a mechanistic point of view. The possible biological implications, potential medical benefits, uncertainties and ...
Can a sponge fractionate isotopes?
Patel, B; Patel, S; Balani, M C
1985-03-22
activities can be modified is by fractionation on the basis of mass of isotope. In view of the remarkable concentration factors observed for stable and radioactive isotopes of the same element and the specific activities reached, it is desirable that species of sponges, especially from the coastal and estuarine environments, be monitored to detect levels of pollution due to anthropogenic substances.
On Fractional Order Hybrid Differential Equations
Directory of Open Access Journals (Sweden)
Mohamed A. E. Herzallah
2014-01-01
Full Text Available We develop the theory of fractional hybrid differential equations with linear and nonlinear perturbations involving the Caputo fractional derivative of order 0<α<1. Using some fixed point theorems we prove the existence of mild solutions for two types of hybrid equations. Examples are given to illustrate the obtained results.
Making Sense of Fractions and Percentages
Whitin, David J.; Whitin, Phyllis
2012-01-01
Because fractions and percentages can be difficult for children to grasp, connecting them whenever possible is beneficial. Linking them can foster representational fluency as children simultaneously see the part-whole relationship expressed numerically (as a fraction and as a percentage) and visually (as a pie chart). NCTM advocates these…
Antidiarrhoeal Activity of Chromatographic Fractions of ...
African Journals Online (AJOL)
Erah
Purpose: The present study was undertaken in order to evaluate the antidiarrhoeal activity of three chromatographic fractions (L, S and Y) of Stereospermum kunthianum stem bark in mice. Methods: Vacuum liquid/column chromatography (VLC/ CC) were used to obtain three fractions (L,S and Y) of Stereospermum ...
Phytotoxic characterization of various fractions of Launaea ...
African Journals Online (AJOL)
Allelopathic screening of various fractions of Launaea procumbens, collected from Wah Cantt (Punjab) Pakistan, was conceded to identify potent allelopathic fraction for future phytochemical analyses. For this purpose, radish root inhibition method was used to test allelopathic potential. Two different concentrations of 100 ...
Gauge invariance and fractional quantized Hall effect
International Nuclear Information System (INIS)
Tao, R.; Wu, Y.S.
1984-01-01
It is shown that gauge invariance arguments imply the possibility of fractional quantized Hall effect; the Hall conductance is accurately quantized to a rational value. The ground state of a system showing the fractional quantized Hall effect must be degenerate; the non-degenerate ground state can only produce the integral quantized Hall effect. 12 references
Fractional supersymmetry through generalized anyonic algebra
International Nuclear Information System (INIS)
Douari, Jamila; Abdus Salam International Centre for Theoretical Physics, Trieste; Hassouni, Yassine
2001-01-01
The construction of anyonic operators and algebra is generalized by using quons operators. Therefore, the particular version of fractional supersymmetry is constructed on the two-dimensional lattice by associating two generalized anyons of different kinds. The fractional supersymmetry Hamiltonian operator is obtained on the two-dimensional lattice and the quantum algebra U q (sl 2 ) is realized. (author)
Stieltjes' continued fraction for the gamma function
International Nuclear Information System (INIS)
Cha, B.W.
1980-01-01
The first forty-one coefficients of a continued fraction for 1n GAMMA(z)+z-(z-1/2) 1n z-1n√2π, are given. The computation, based on Wall's algorithm for converting a function's power series representation to a continued fraction representation, was run on the algebraic manipulation system MACSYMA
An analytical solution of fractional burgers equation
Directory of Open Access Journals (Sweden)
Pang Jing
2017-01-01
Full Text Available Using the fractional complex transform, the fractional partial differential equations can be reduced to ordinary differential equations which can be solved by the auxiliary equation method. Non-linear superposition formulation of Riccati equation is applied, and a complex infinite sequence solution is obtained.
Representations of the Magnitudes of Fractions
Schneider, Michael; Siegler, Robert S.
2010-01-01
We tested whether adults can use integrated, analog, magnitude representations to compare the values of fractions. The only previous study on this question concluded that even college students cannot form such representations and instead compare fraction magnitudes by representing numerators and denominators as separate whole numbers. However,…
A Computational Model of Fraction Arithmetic
Braithwaite, David W.; Pyke, Aryn A.; Siegler, Robert S.
2017-01-01
Many children fail to master fraction arithmetic even after years of instruction, a failure that hinders their learning of more advanced mathematics as well as their occupational success. To test hypotheses about why children have so many difficulties in this area, we created a computational model of fraction arithmetic learning and presented it…
Fractions Learning in Children with Mathematics Difficulties
Tian, Jing; Siegler, Robert S.
2017-01-01
Learning fractions is difficult for children in general and especially difficult for children with mathematics difficulties (MD). Recent research on developmental and individual differences in fraction knowledge of children with MD and typically achieving (TA) children has demonstrated that U.S. children with MD start middle school behind their TA…
12 CFR 5.67 - Fractional shares.
2010-01-01
... Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY RULES, POLICIES, AND PROCEDURES FOR CORPORATE ACTIVITIES Payment of Dividends § 5.67 Fractional shares. To avoid complicated recordkeeping in connection with fractional shares, a national bank issuing additional stock by stock dividend, upon...
Procedural and Conceptual Knowledge: Adults Reviewing Fractions
Baker, William J.; Czarnocha, Bronislaw; Dias, Olen; Doyle, Kathleen; Kennis, James R.
2012-01-01
In the United States a majority of the students who enroll in community colleges require a review of secondary math before they are eligible for college level mathematics. In the pre-algebra course, that has a high drop-out rate, the most difficult topic for students is fractions. In order to better understand the fraction concept, Kieren…
psychrometry: from partial pressures to mole fractions
African Journals Online (AJOL)
ES Obe
1980-03-01
Mar 1, 1980 ... ABSTRACT. This study uses the viria1 and interaction coefficients of the normal air components in deriving compressibility factors and thereafter a simple iterative formulation for mole fractions. Conversion from partial pressures to mole fractions now becomes tractable by means of determinate multipliers.
Cell fractionation of parasitic protozoa: a review
Directory of Open Access Journals (Sweden)
Souza Wanderley de
2003-01-01
Full Text Available Cell fractionation, a methodological strategy for obtaining purified organelle preparations, has been applied successfully to parasitic protozoa by a number of investigators. Here we present and discuss the work of several groups that have obtained highly purified subcellular fractions from trypanosomatids, Apicomplexa and trichomonads, and whose work have added substantially to our knowledge of the cell biology of these parasites.
Using Technology Effectively to Teach about Fractions
Hensberry, Karina K. R.; Moore, Emily B.; Perkins, Katherine
2015-01-01
In this article, the authors describe classroom use of technology that successfully engaged fourth grade students (typically aged 9-10) in the United States in learning about fractions. The activities involved the use of an interactive simulation designed to support student learning of fractions, and whole-class discussion where students were…
Assessing Students' Understanding of Fraction Multiplication
Rumsey, Chepina; Guarino, Jody; Beltramini, Jennie; Cole, Shelbi; Farmer, Alicia; Gray, Kristin; Saxby, Morgan
2016-01-01
In this article the authors describe a project during which they unpacked fraction standards, created rigorous tasks and lesson plans, and developed formative and summative assessments to analyze students' thinking about fraction multiplication. The purpose of this article is to (1) illustrate a process that can be replicated by educators…
International Nuclear Information System (INIS)
Sugano, Yasutaka; Mizuta, Masahiro; Takao, Seishin; Shirato, Hiroki; Sutherland, Kenneth L.; Date, Hiroyuki
2015-01-01
Purpose: Radiotherapy of solid tumors has been performed with various fractionation regimens such as multi- and hypofractionations. However, the ability to optimize the fractionation regimen considering the physical dose distribution remains insufficient. This study aims to optimize the fractionation regimen, in which the authors propose a graphical method for selecting the optimal number of fractions (n) and dose per fraction (d) based on dose–volume histograms for tumor and normal tissues of organs around the tumor. Methods: Modified linear-quadratic models were employed to estimate the radiation effects on the tumor and an organ at risk (OAR), where the repopulation of the tumor cells and the linearity of the dose-response curve in the high dose range of the surviving fraction were considered. The minimization problem for the damage effect on the OAR was solved under the constraint that the radiation effect on the tumor is fixed by a graphical method. Here, the damage effect on the OAR was estimated based on the dose–volume histogram. Results: It was found that the optimization of fractionation scheme incorporating the dose–volume histogram is possible by employing appropriate cell surviving models. The graphical method considering the repopulation of tumor cells and a rectilinear response in the high dose range enables them to derive the optimal number of fractions and dose per fraction. For example, in the treatment of prostate cancer, the optimal fractionation was suggested to lie in the range of 8–32 fractions with a daily dose of 2.2–6.3 Gy. Conclusions: It is possible to optimize the number of fractions and dose per fraction based on the physical dose distribution (i.e., dose–volume histogram) by the graphical method considering the effects on tumor and OARs around the tumor. This method may stipulate a new guideline to optimize the fractionation regimen for physics-guided fractionation
Accelerated fractionation in advanced head and neck cancer
International Nuclear Information System (INIS)
Olmi, P.; Cellai, E.; Chiavacci, A.; Fablai, C.
1990-01-01
From 1975 to 1985, 161 patients affected by head and neck cancer (58 oropharynx, 67 oral cavity, 36 paranasal sinuses) were treated with radiotherapy using an accelerated fractionation (AF) schedule at the University and Hospital Radiotherapy Departments of Florence. Five-year actuarial local control and survival was 38% for the oropharynx, 18% and 20% for the oral cavity, and 38% and 31% for the paranasal sinuses. Results were analysed according to T and N stage as well. Severe late sequelae were evaluated in 53 patients without local disease and with a minimum follow-up of one year: 8 patients developed osteonecrosis; there were 3 cases of trismus, 2 cases of laryngeal oedema, one case of blindness and one case of opththalmitis. (author). 19 refs.; 2 figs.; 9 tabs
Accelerated fractionation in advanced head and neck cancer
Energy Technology Data Exchange (ETDEWEB)
Olmi, P.; Cellai, E. (Florence University (Italy). Department of Radiotherapy); Chiavacci, A.; Fablai, C. (Florence Hospital (Italy). Department of Radiotherapy)
1990-03-01
From 1975 to 1985, 161 patients affected by head and neck cancer (58 oropharynx, 67 oral cavity, 36 paranasal sinuses) were treated with radiotherapy using an accelerated fractionation (AF) schedule at the University and Hospital Radiotherapy Departments of Florence. Five-year actuarial local control and survival was 38% for the oropharynx, 18% and 20% for the oral cavity, and 38% and 31% for the paranasal sinuses. Results were analysed according to T and N stage as well. Severe late sequelae were evaluated in 53 patients without local disease and with a minimum follow-up of one year: 8 patients developed osteonecrosis; there were 3 cases of trismus, 2 cases of laryngeal oedema, one case of blindness and one case of opththalmitis. (author). 19 refs.; 2 figs.; 9 tabs.
International Nuclear Information System (INIS)
1994-12-01
This document contains compiled data from the DOE Handbook on Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear facilities. Source data and example facilities utilized, such as the Plutonium Recovery Facility, are included
Reply to "Comment on 'Fractional quantum mechanics' and 'Fractional Schrödinger equation' ".
Laskin, Nick
2016-06-01
The fractional uncertainty relation is a mathematical formulation of Heisenberg's uncertainty principle in the framework of fractional quantum mechanics. Two mistaken statements presented in the Comment have been revealed. The origin of each mistaken statement has been clarified and corrected statements have been made. A map between standard quantum mechanics and fractional quantum mechanics has been presented to emphasize the features of fractional quantum mechanics and to avoid misinterpretations of the fractional uncertainty relation. It has been shown that the fractional probability current equation is correct in the area of its applicability. Further studies have to be done to find meaningful quantum physics problems with involvement of the fractional probability current density vector and the extra term emerging in the framework of fractional quantum mechanics.
Neutron Imaging Calibration to Measure Void Fraction
Energy Technology Data Exchange (ETDEWEB)
Geoghegan, Patrick J [ORNL; Bilheux, Hassina Z [ORNL; Sharma, Vishaldeep [ORNL; Fricke, Brian A [ORNL
2015-01-01
Void fraction is an intuitive parameter that describes the fraction of vapor in a two-phase flow. It appears as a key variable in most heat transfer and pressure drop correlations used to design evaporating and condensing heat exchangers, as well as determining charge inventory in refrigeration systems. Void fraction measurement is not straightforward, however, and assumptions on the invasiveness of the measuring technique must be made. Neutron radiography or neutron imaging has the potential to be a truly non-invasive void fraction measuring technique but has until recently only offered qualitative descriptions of two-phase flow, in terms of flow maldistributions, for example. This paper describes the calibration approach necessary to employ neutron imaging to measure steady-state void fraction. Experiments were conducted at the High Flux Isotope Reactor (HFIR) Cold Guide 1D neutron imaging facility at Oak Ridge National Laboratory (ORNL), Oak Ridge, TN, USA.
Variable-order fuzzy fractional PID controller.
Liu, Lu; Pan, Feng; Xue, Dingyu
2015-03-01
In this paper, a new tuning method of variable-order fractional fuzzy PID controller (VOFFLC) is proposed for a class of fractional-order and integer-order control plants. Fuzzy logic control (FLC) could easily deal with parameter variations of control system, but the fractional-order parameters are unable to change through this way and it has confined the effectiveness of FLC. Therefore, an attempt is made in this paper to allow all the five parameters of fractional-order PID controller vary along with the transformation of system structure as the outputs of FLC, and the influence of fractional orders λ and μ on control systems has been investigated to make the fuzzy rules for VOFFLC. Four simulation results of different plants are shown to verify the availability of the proposed control strategy. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.
Generalized Fractional Derivative Anisotropic Viscoelastic Characterization
Directory of Open Access Journals (Sweden)
Harry H. Hilton
2012-01-01
Full Text Available Isotropic linear and nonlinear fractional derivative constitutive relations are formulated and examined in terms of many parameter generalized Kelvin models and are analytically extended to cover general anisotropic homogeneous or non-homogeneous as well as functionally graded viscoelastic material behavior. Equivalent integral constitutive relations, which are computationally more powerful, are derived from fractional differential ones and the associated anisotropic temperature-moisture-degree-of-cure shift functions and reduced times are established. Approximate Fourier transform inversions for fractional derivative relations are formulated and their accuracy is evaluated. The efficacy of integer and fractional derivative constitutive relations is compared and the preferential use of either characterization in analyzing isotropic and anisotropic real materials must be examined on a case-by-case basis. Approximate protocols for curve fitting analytical fractional derivative results to experimental data are formulated and evaluated.
A Note on Fractional Differential Equations with Fractional Separated Boundary Conditions
Directory of Open Access Journals (Sweden)
Bashir Ahmad
2012-01-01
Full Text Available We consider a new class of boundary value problems of nonlinear fractional differential equations with fractional separated boundary conditions. A connection between classical separated and fractional separated boundary conditions is developed. Some new existence and uniqueness results are obtained for this class of problems by using standard fixed point theorems. Some illustrative examples are also discussed.
van Dongen, Joris A.; Stevens, Hieronymus P.; Parvizi, Mojtaba; van der Lei, Berend; Harmsen, Martin C.
2016-01-01
Autologous adipose tissue transplantation is clinically used to reduce dermal scarring and to restore volume loss. The therapeutic benefit on tissue damage more likely depends on the stromal vascular fraction of adipose tissue than on the adipocyte fraction. This stromal vascular fraction can be
Directory of Open Access Journals (Sweden)
Dipanjan Majumder
2012-01-01
Conclusions: Different fractionation of radiation has same response and toxicity in treatment of vertebral bone metastasis. Single fraction RT may be safely used to treat these cases as this is more cost effective and less time consuming. Studies may be conducted to find out particular subgroup of patients to be benefitted more by either fractionation schedule; however, our study cannot comment on that issue.
Directory of Open Access Journals (Sweden)
Sheng-Ping Yan
2014-01-01
Full Text Available We perform a comparison between the local fractional Adomian decomposition and local fractional function decomposition methods applied to the Laplace equation. The operators are taken in the local sense. The results illustrate the significant features of the two methods which are both very effective and straightforward for solving the differential equations with local fractional derivative.
Survival analysis II: Cox regression
Stel, Vianda S.; Dekker, Friedo W.; Tripepi, Giovanni; Zoccali, Carmine; Jager, Kitty J.
2011-01-01
In contrast to the Kaplan-Meier method, Cox proportional hazards regression can provide an effect estimate by quantifying the difference in survival between patient groups and can adjust for confounding effects of other variables. The purpose of this article is to explain the basic concepts of the
Long-term haemodialysis survival
DEFF Research Database (Denmark)
Heaf, James; Nielsen, Arne Høj; Hansen, Henrik Post
2012-01-01
Haemodialysis (HD) treatment for end-stage renal disease bears a poor prognosis. We present a case of a patient who, apart from two transplant periods lasting 8 months in all, was treated with conventional in-centre HD three times a week and who survived for 41 years. Patients should be aware tha...
Survivability of SCADA Control Loop
Camacho, José; de Boer, Pieter-Tjerk; Remke, Anne Katharina Ingrid
2009-01-01
The endorsement of information technologies for critical infrastructures control introduces new threats in their security and surveillance. Along with certain level of protection against attacks, it is desirable for critical processes to survive even if they succeed. A stochastic Petri Nets-based
Ghosh, Saptarshi; Rao, Pamidimukkala Bramhananda; Kotne, Sivasankar
2015-01-01
Although 3D image based brachytherapy is currently the standard of treatment in cervical cancer, most of the centres in developing countries still practice orthogonal intracavitary brachytherapy due to financial constraints. The quest for optimum dose and fractionation schedule in high dose rate (HDR) intracavitary brachytherapy (ICBT) is still ongoing. While the American Brachytherapy Society recommends four to eight fractions of each less than 7.5 Gy, there are some studies demonstrating similar efficacy and comparable toxicity with higher doses per fraction. To assess the treatment efficacy and late complications of HDR ICBT with 9 Gy per fraction in two fractions. This is a prospective institutional study in Southern India carried on from 1st June 2012 to 31st July 2014. In this period, 76 patients of cervical cancer satisfying our inclusion criteria were treated with concurrent chemo-radiation following ICBT with 9 Gy per fraction in two fractions, five to seven days apart. The median follow-up period in the study was 24 months (range 10.6 - 31.2 months). The 2 year actuarial local control rate, disease-free survival and overall survival were 88.1%, 84.2% and 81.8% respectively. Although 38.2% patients suffered from late toxicity, only 3 patients had grade III late toxicity. In our experience, HDR brachytherapy with 9 Gy per fraction in two fractions is an effective dose fractionation for the treatment of cervical cancer with acceptable toxicity.
A study of the effect of fractional gamma irradiation of leptospirae
International Nuclear Information System (INIS)
Vasilevska, M.; Khristova, M.; Yankova, N.; Pandev, I.
1977-01-01
In view of the theoretical and practical interest in obtaining antigens from killed leptospirae for immune or diagnostic serums, a two hour leptospiral culture from the pathogenic strain Pomona (Calapica) was fractionally gamma-irradiated with a total dose of 2 Mrad. Changes were observed in the size, motility and survival duration of the leptospiral strains. The results are interpreted and compared with those of single administration of the same dose, studied in a previous work. (author)
Single-dose and fractionated irradiation of four human lung cancer cell lines in vitro
International Nuclear Information System (INIS)
Brodin, O.; Lennartsson, L.; Nilsson, S.
1991-01-01
Four established human lung cancer cell lines were exposed to single-dose irradiation. The survival curves of 2 small cell lung carcinomas (SCLC) were characterized by a limited capacity for repair with small and moderate shoulders with extrapolation numbers (n) of 1.05 and 1.60 respectively. Two non-small cell lung carcinoma (NSCLC) cell lines, one squamous cell (SQCLC) and one large cell (LCLC) had large shoulders with n-values of 73 and 15 respectively. The radiosensitivity when measured as D 0 did not, however, differ as much from cell line to cell line, with values from 1.22 to 1.65. The surviving fraction after 2 Gy (SF2) was 0.24 and 0.42 respectively in the SCLC cell lines and 0.90 and 0.88 respectively in the NSCLC cell lines. Fractionated irradiation delivered according to 3 different schedules was also investigated. All the schedules delivered a total dose of 10 Gy in 5 days and were applied in 1, 2 and 5 Gy dose fractions respectively. Survival followed the pattern found after single-dose irradiation; it was lowest in the SCLC cell line with the lowest SF and highest in the two NSCLC cell lines. In the SCLC cell lines all schedules were approximately equally efficient. In the LCLC and in the SQCLC cell lines, the 5 Gy schedule killed more cells than the 1 and 2 Gy schedules. The results indicate that the size of the shoulder of the survival curve is essential when choosing the most tumoricidal fractionation schedule. (orig.)
Effect of fractionated hyperthermia on hypoxic cells in vitro
International Nuclear Information System (INIS)
Nielson, O.S.
1981-01-01
The lethal response of asynchronous exponentially growing mouse lung (L1A2) cells heated to 42 0 C under hypoxic conditions was demonstrated in vitro. Acutely hypoxic cells (i.e. heated immediately after 30 min of N 2 +CO 2 gassing) and aerobic cells treated under the same extracellular pH were equally sensitive to a single hyperthermic treatment, and incubation under hypoxia for up to 24 hours prior to treatment did not influence cell survival. Similarly, under controlled pH conditions (pH within 7.0 to 7.4) recovery from hyperthermic damage demonstrated by two-dose hyperthermic fractionation (each of 1.5 hours at 42 0 C) was identical in hypoxic and aerobic cells, and the highest recovery was found at a 10-hour interval Preheating for 1.5 hours at 42 0 C induced thermal resistance. to a second treatment at 42 0 C (thermotolerance). At the 10-hour interval the degree of thermotolerance was not influenced by incubation under hypoxic conditions (thermotolerance ratio, TTR = 4.7 in both aerobic and hypoxic cells). The data indicate that hypoxic conditions do not influence the heat response in L1A2 cells to either a single or a two-dose fractionated hyperthermic treatment in which hypoxia or aerobic conditions were maintained in the interval between the heat treatments. (author)
Fractional Bhatnagar-Gross-Krook kinetic equation
Goychuk, Igor
2017-11-01
The linear Boltzmann equation (LBE) approach is generalized to describe fractional superdiffusive transport of the Lévy walk type in external force fields. The time distribution between scattering events is assumed to have a finite mean value and infinite variance. It is completely characterized by the two scattering rates, one fractional and a normal one, which defines also the mean scattering rate. We formulate a general fractional LBE approach and exemplify it with a particularly simple case of the Bohm and Gross scattering integral leading to a fractional generalization of the Bhatnagar, Gross and Krook (BGK) kinetic equation. Here, at each scattering event the particle velocity is completely randomized and takes a value from equilibrium Maxwell distribution at a given fixed temperature. We show that the retardation effects are indispensable even in the limit of infinite mean scattering rate and argue that this novel fractional kinetic equation provides a viable alternative to the fractional Kramers-Fokker-Planck (KFP) equation by Barkai and Silbey and its generalization by Friedrich et al. based on the picture of divergent mean time between scattering events. The case of divergent mean time is also discussed at length and compared with the earlier results obtained within the fractional KFP. Also a phenomenological fractional BGK equation without retardation effects is proposed in the limit of infinite scattering rates. It cannot be, however, rigorously derived from a scattering model, being rather clever postulated. It this respect, this retardationless equation is similar to the fractional KFP by Barkai and Silbey. However, it corresponds to the opposite, much more physical limit and, therefore, also presents a viable alternative.
Use of the LQ model with large fraction sizes results in underestimation of isoeffect doses
International Nuclear Information System (INIS)
Sheu, Tommy; Molkentine, Jessica; Transtrum, Mark K.; Buchholz, Thomas A.; Withers, Hubert Rodney; Thames, Howard D.; Mason, Kathy A.
2013-01-01
Purpose: To test the appropriateness of the linear-quadratic (LQ) model to describe survival of jejunal crypt clonogens after split doses with variable (small 1–6 Gy, large 8–13 Gy) first dose, as a model of its appropriateness for both small and large fraction sizes. Methods: C3Hf/KamLaw mice were exposed to whole body irradiation using 300 kVp X-rays at a dose rate of 1.84 Gy/min, and the number of viable jejunal crypts was determined using the microcolony assay. 14 Gy total dose was split into unequal first and second fractions separated by 4 h. Data were analyzed using the LQ model, the lethal potentially lethal (LPL) model, and a repair-saturation (RS) model. Results: Cell kill was greater in the group receiving the larger fraction first, creating an asymmetry in the plot of survival vs size of first dose, as opposed to the prediction of the LQ model of a symmetric response. There was a significant difference in the estimated βs (higher β after larger first doses), but no significant difference in the αs, when large doses were given first vs small doses first. This difference results in underestimation (based on present data by approximately 8%) of isoeffect doses using LQ model parameters based on small fraction sizes. While the LPL model also predicted a symmetric response inconsistent with the data, the RS model results were consistent with the observed asymmetry. Conclusion: The LQ model underestimates doses for isoeffective crypt-cell survival with large fraction sizes (in the present setting, >9 Gy)
Biological and dosimetric characterisation of spatially fractionated proton minibeams
Meyer, Juergen; Stewart, Robert D.; Smith, Daniel; Eagle, James; Lee, Eunsin; Cao, Ning; Ford, Eric; Hashemian, Reza; Schuemann, Jan; Saini, Jatinder; Marsh, Steve; Emery, Robert; Dorman, Eric; Schwartz, Jeff; Sandison, George
2017-12-01
The biological effectiveness of proton beams varies with depth, spot size and lateral distance from the beam central axis. The aim of this work is to incorporate proton relative biological effectiveness (RBE) and equivalent uniform dose (EUD) considerations into comparisons of broad beam and highly modulated proton minibeams. A Monte Carlo model of a small animal proton beamline is presented. Dose and variable RBE is calculated on a per-voxel basis for a range of energies (30–109 MeV). For an open beam, the RBE values at the beam entrance ranged from 1.02–1.04, at the Bragg peak (BP) from 1.3 to 1.6, and at the distal end of the BP from 1.4 to 2.0. For a 50 MeV proton beam, a minibeam collimator designed to produce uniform dose at the depth of the BP peak, had minimal impact on the open beam RBE values at depth. RBE changes were observed near the surface when the collimator was placed flush with the irradiated object, due to a higher neutron contribution derived from proton interactions with the collimator. For proton minibeams, the relative mean RBE weighted entrance dose (RWD) was ~25% lower than the physical mean dose. A strong dependency of the EUD with fraction size was observed. For 20 Gy fractions, the EUD varied widely depending on the radiosensitivity of the cells. For radiosensitive cells, the difference was up to ~50% in mean dose and ~40% in mean RWD and the EUD trended towards the valley dose rather than the mean dose. For comparative studies of uniform dose with spatially fractionated proton minibeams, EUD derived from a per-voxel RWD distribution is recommended for biological assessments of reproductive cell survival and related endpoints.
International Nuclear Information System (INIS)
Chang, Daniel T.; Amdur, Robert J.; Morris, Christopher G. M.S.; Mendenhall, William M.
2006-01-01
Purpose: To examine locoregional control after adjuvant radiotherapy (RT) for cutaneous melanoma and compare outcomes between conventional fractionation and hypofractionation. Methods and Materials: Between January 1980 and June 2004, 56 patients with high-risk disease were treated with adjuvant RT. Indications for RT included: recurrent disease, cervical lymph node involvement, lymph nodes >3 cm, more than three lymph nodes involved, extracapsular extension, gross residual disease, close or positive margins, or satellitosis. Hypofractionation was used in 41 patients (73%) and conventional fractionation was used in 15 patients (27%). Results: The median age was 61 years (21->90). The median follow-up among living patients was 4.4 years (range, 0.6-14.4 years). The primary site was located in the head and neck in 49 patients (87%) and below the clavicles in 7 patients (13%). There were 7 in-field locoregional failures (12%), 3 out-of-field regional failures (5%), and 24 (43%) distant failures. The 5-year in-field locoregional control (ifLRC) and freedom from distant metastases (FFDM) rates were 87% and 43%, respectively. The 5-year cause-specific (CSS) and overall survival (OS) was 57% and 46%, respectively. The only factor associated with ifLRC was satellitosis (p = 0.0002). Nodal involvement was the only factor associated with FFDM (p = 0.0007), CSS (p = 0.0065), and OS (p = 0.016). Two patients (4%) who experienced severe late complications, osteoradionecrosis of the temporal bone and radiation plexopathy, and both received hypofractionation (5%). Conclusions: Although surgery and adjuvant RT provides excellent locoregional control, distant metastases remain the major cause of mortality. Hypofractionation and conventional fractionation are equally efficacious
Fractional calculus an introduction for physicists
Herrmann, Richard
2011-01-01
Fractional calculus is undergoing rapidly and ongoing development. We can already recognize, that within its framework new concepts and strategies emerge, which lead to new challenging insights and surprising correlations between different branches of physics. This book is an invitation both to the interested student and the professional researcher. It presents a thorough introduction to the basics of fractional calculus and guides the reader directly to the current state-of-the-art physical interpretation. It is also devoted to the application of fractional calculus on physical problems, in t
Fractional calculus in bioengineering, part 3.
Magin, Richard L
2004-01-01
Fractional calculus (integral and differential operations of noninteger order) is not often used to model biological systems. Although the basic mathematical ideas were developed long ago by the mathematicians Leibniz (1695), Liouville (1834), Riemann (1892), and others and brought to the attention of the engineering world by Oliver Heaviside in the 1890s, it was not until 1974 that the first book on the topic was published by Oldham and Spanier. Recent monographs and symposia proceedings have highlighted the application of fractional calculus in physics, continuum mechanics, signal processing, and electromagnetics, but with few examples of applications in bioengineering. This is surprising because the methods of fractional calculus, when defined as a Laplace or Fourier convolution product, are suitable for solving many problems in biomedical research. For example, early studies by Cole (1933) and Hodgkin (1946) of the electrical properties of nerve cell membranes and the propagation of electrical signals are well characterized by differential equations of fractional order. The solution involves a generalization of the exponential function to the Mittag-Leffler function, which provides a better fit to the observed cell membrane data. A parallel application of fractional derivatives to viscoelastic materials establishes, in a natural way, hereditary integrals and the power law (Nutting/Scott Blair) stress-strain relationship for modeling biomaterials. In this review, I will introduce the idea of fractional operations by following the original approach of Heaviside, demonstrate the basic operations of fractional calculus on well-behaved functions (step, ramp, pulse, sinusoid) of engineering interest, and give specific examples from electrochemistry, physics, bioengineering, and biophysics. The fractional derivative accurately describes natural phenomena that occur in such common engineering problems as heat transfer, electrode/electrolyte behavior, and sub
Hypo fractionated prostate treatment by volumearcotherapy modulated
International Nuclear Information System (INIS)
Clemente Gutierrez, F.; Perez Vara, C.; Prieto Villacorta, M.
2013-01-01
Several studies have been proposed over the years schemes of hypo-fractionated treatment for prostate cancer. Such schemes have been designed in order to increase local control of the disease and reduce complications. They are in addition a clear improvement from the point of view logistical and organizational for treatment centres and the patient. the hypo-fractionated treatments are possible because the ratio a/b for prostate carcinoma is comparable, and even below, the surrounding healthy tissues. This work presents the scheme adopted in our Center for the hypo-fractionated treatment of the cancer of prostate by arco therapy volumetric modulated. (Author)
State space realization of fractional order systems
International Nuclear Information System (INIS)
Djamah, T.; Mansouri, R.; Djennoune, S.; Bettayeb, M.
2009-01-01
In the past few years, fractional calculus appeared to be a useful tool for the modeling and control of dynamic systems. Although, some methods of the control theory have been developed for the commensurate case, the difficulties of the non commensurate called generalized fractional systems still remain unsolved. In this paper, a method is presented for obtaining the state space model of a generalized fractional system starting from its transfer function. The method remains valid for the particular cases of commensurate and integer systems. An application to some examples illustrates the algorithm.
Approximate Controllability of Fractional Integrodifferential Evolution Equations
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R. Ganesh
2013-01-01
Full Text Available This paper addresses the issue of approximate controllability for a class of control system which is represented by nonlinear fractional integrodifferential equations with nonlocal conditions. By using semigroup theory, p-mean continuity and fractional calculations, a set of sufficient conditions, are formulated and proved for the nonlinear fractional control systems. More precisely, the results are established under the assumption that the corresponding linear system is approximately controllable and functions satisfy non-Lipschitz conditions. The results generalize and improve some known results.
Approximated Fractional Order Chebyshev Lowpass Filters
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Todd Freeborn
2015-01-01
Full Text Available We propose the use of nonlinear least squares optimization to approximate the passband ripple characteristics of traditional Chebyshev lowpass filters with fractional order steps in the stopband. MATLAB simulations of (1+α, (2+α, and (3+α order lowpass filters with fractional steps from α = 0.1 to α = 0.9 are given as examples. SPICE simulations of 1.2, 1.5, and 1.8 order lowpass filters using approximated fractional order capacitors in a Tow-Thomas biquad circuit validate the implementation of these filter circuits.
Applications of fractional calculus in physics
2000-01-01
Fractional calculus is a collection of relatively little-known mathematical results concerning generalizations of differentiation and integration to noninteger orders. While these results have been accumulated over centuries in various branches of mathematics, they have until recently found little appreciation or application in physics and other mathematically oriented sciences. This situation is beginning to change, and there are now a growing number of research areas in physics which employ fractional calculus.This volume provides an introduction to fractional calculus for physicists, and co
The calculation of ion fractions in LEIS
Verbist, G.; Brongersma, H. H.; Devreese, J. T.
1992-02-01
We discuss different ways of calculating ion fractions for LEIS-type experiments: (i) parametrizations, and (ii) quasi-ab-initio models. Among the different parametrizations of the neutralization rates the Hagstrum, Godfrey-Woodruff and the unified model are compared. For surfaces containing different types of atoms, e.g. NaCl, it is not possible to determine the neutralization constants uniquely. This is related to the use of relative ion fractions. For the absolute ion fractions there is a convincing agreement between DISC-experiments for He + → Si scattering and a theoretical calculation on the basis of the quasi-ab-initio Muda-Newns model.
International Nuclear Information System (INIS)
Lei Suwen; Su Xu; Wang Jifang; Li Wenjian
2003-01-01
Objective: To investigate the survival fraction of a human liver cancer cell line SMMC-7721 following irradiation with carbon ions with different LET. Methods: cells of the human liver cancer cell line SMMC-7721 were irradiated with carbon ions (LET=30 and 70 keV/μm). The survival fraction was determined with clonogenic assay after 9 days incubation in a 5% CO 2 incubator at 37 degree C. Results: When the survival fractions of 70 keV/μm were D s = 0.1 and D s=0.01 absorption dose were 2.94 and 5.88 Gy respectively, and those of 30 keV/μm were 4.00 and 8.00 Gy respectively. Conclusion: For the SMMC-7721 cell line, 70 keV/μm is more effective for cell killing than 30 keV/μm
International Nuclear Information System (INIS)
Begg, A.C.
1987-01-01
Drugs which inhibit the repair of radiation damage could potentially be useful for enhancing the effects of radiotherapy. In pre-clinical combined modality studies, however, it is often difficult to state with certainty whether or not a drug has inhibited radiation damage repair. This paper shows that several commonly used parameters for assessing repair can give the wrong answer regarding the presence of drug-induced repair inhibition. These parameters are; the difference in radiation dose between 1 and n fractions to give the same effect, the fractional recovered dose per fraction interval, FR, and the related parameter FREC. A further parameter used for treatment comparisons is the enhancement ratio for the drug (D.E.R.; ratio of radiation doses, with and without drug, to cause a given effect). An increasing D.E.R. with increasing number of radiation fractions has been taken as an indication that the drug inhibited repair. The present report demonstrates that this, too, can be misleading. From an analysis based on a linear-quadratic survival curve for X rays, it is suggested that deriving and comparing alpha/beta ratios (ratio of the linea to quadratic coefficients) gives the best indication of drug-induced changes in survival curve shape which may reflect underlying changes in repair capacity
Lee, Jung-Woo; Shin, Jung-Gul; Kim, Eun Hee; Kang, Hae Eun; Yim, In Been; Kim, Ji Yeon; Joo, Hong-Gu; Woo, Hee Jong
2004-03-01
The immunomodulatory and antitumor effects of lactic acid bacteria (LABs) were investigated. Cytoplasmic fraction of Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium longum were tested for the antiproliferative activity in vitro to SNUC2A, SNU1, NIH/3T3 and Jurkat cell lines by crystal violet assay. All cytoplasmic fraction suppressed proliferation of tumor cells, though L. casei and B. longum were more effective. From these results, cytoplasmic fraction of L. casei and B. longum with Y400 as a control were administered as dietary supplements to Balb/c mice for 2, and 4 consecutive wks. Administration for 4 wks enhanced the number of total T cells, NK cells and MHC class II+ cells, and CD4-CD8+ T cells in flow cytometry analysis. To determine of antitumor activity of LABs preparation in vivo, F9 teratocarcinoma cells were inoculated on mice at 14th day. Body weight was decreased with increased survival rate in all groups with the cytoplasm of LABs. Our results showed that cytoplasmic fraction of LABs had direct antiproliferative effects on tumor cell lines in vitro, effects on immune cells in vivo, and antitumor effects on tumor-bearing mice with prolonged survival periods.
Individual social capital and survival
DEFF Research Database (Denmark)
Ejlskov, Linda; Mortensen, Rikke N; Overgaard, Charlotte
2014-01-01
BACKGROUND: The concept of social capital has received increasing attention as a determinant of population survival, but its significance is uncertain. We examined the importance of social capital on survival in a population study while focusing on gender differences. METHODS: We used data from...... a Danish regional health survey with a five-year follow-up period, 2007-2012 (n = 9288, 53.5% men, 46.5% women). We investigated the association between social capital and all-cause mortality, performing separate analyses on a composite measure as well as four specific dimensions of social capital while...... controlling for covariates. Analyses were performed with Cox proportional hazard models by which hazard ratios and 95% confidence intervals were calculated. RESULTS: For women, higher levels of social capital were associated with lower all-cause mortality regardless of age, socioeconomic status, health...
51Cr - erythrocyte survival curves
International Nuclear Information System (INIS)
Paiva Costa, J. de.
1982-07-01
Sixteen patients were studied, being fifteen patients in hemolytic state, and a normal individual as a witness. The aim was to obtain better techniques for the analysis of the erythrocytes, survival curves, according to the recommendations of the International Committee of Hematology. It was used the radiochromatic method as a tracer. Previously a revisional study of the International Literature was made in its aspects inherent to the work in execution, rendering possible to establish comparisons and clarify phonomena observed in cur investigation. Several parameters were considered in this study, hindering both the exponential and the linear curves. The analysis of the survival curves of the erythrocytes in the studied group, revealed that the elution factor did not present a homogeneous answer quantitatively to all, though, the result of the analysis of these curves have been established, through listed programs in the electronic calculator. (Author) [pt
Saudi sands, SCUDS, and survival.
Glendon, M P
1993-01-01
SCUD attacks were one of many challenges this pediatric nurse practitioner (NP) and Air Force Reserve flight nurse faced daily during Desert Shield and Desert Storm. Providing nursing care to sick and injured patients on board a C141 transport plane en route from Saudi Arabia to Germany was her primary responsibility. Additionally, many hours were spent filling sandbags, attending in-service classes, and practicing putting on a gas mask and protective suit. Although the war has been over for almost 3 years, the effects are long lasting. The author was able to use her wartime experience positively to gain insight into survival in today's violent society. As violence increases, NPs must reshape their focus and educate their clients about survival.
Campylobacter virulence and survival factors.
Bolton, Declan J
2015-06-01
Despite over 30 years of research, campylobacteriosis is the most prevalent foodborne bacterial infection in many countries including in the European Union and the United States of America. However, relatively little is known about the virulence factors in Campylobacter or how an apparently fragile organism can survive in the food chain, often with enhanced pathogenicity. This review collates information on the virulence and survival determinants including motility, chemotaxis, adhesion, invasion, multidrug resistance, bile resistance and stress response factors. It discusses their function in transition through the food processing environment and human infection. In doing so it provides a fundamental understanding of Campylobacter, critical for improved diagnosis, surveillance and control. Copyright © 2014 Elsevier Ltd. All rights reserved.
Complexity for survival of livings
International Nuclear Information System (INIS)
Zak, Michail
2007-01-01
A connection between survivability of livings and complexity of their behavior is established. New physical paradigms-exchange of information via reflections, and chain of abstractions-explaining and describing progressive evolution of complexity in living (active) systems are introduced. A biological origin of these paradigms is associated with a recently discovered mirror neuron that is able to learn by imitation. As a result, an active element possesses the self-nonself images and interacts with them creating the world of mental dynamics. Three fundamental types of complexity of mental dynamics that contribute to survivability are identified. Mathematical model of the corresponding active systems is described by coupled motor-mental dynamics represented by Langevin and Fokker-Planck equations, respectively, while the progressive evolution of complexity is provided by nonlinear evolution of probability density. Application of the proposed formalism to modeling common-sense-based decision-making process is discussed
Tunneling time in space fractional quantum mechanics
Hasan, Mohammad; Mandal, Bhabani Prasad
2018-02-01
We calculate the time taken by a wave packet to travel through a classically forbidden region of space in space fractional quantum mechanics. We obtain the close form expression of tunneling time from a rectangular barrier by stationary phase method. We show that tunneling time depends upon the width b of the barrier for b → ∞ and therefore Hartman effect doesn't exist in space fractional quantum mechanics. Interestingly we found that the tunneling time monotonically reduces with increasing b. The tunneling time is smaller in space fractional quantum mechanics as compared to the case of standard quantum mechanics. We recover the Hartman effect of standard quantum mechanics as a special case of space fractional quantum mechanics.
Some Improvements of Conformable Fractional Integral Inequalities
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Fuat Usta
2017-07-01
Full Text Available In this study, we wish to set up and present some new conformable fractional integral inequalities of the Gronwall type which have a great variety of implementation area in differential and integral equations.
Steffensen's integral inequality for conformable fractional integrals
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Mehmet Zeki Sarikaya
2017-09-01
Full Text Available The aim of this paper is to establish some Steffensen’s type inequalities for conformable fractional integral. The results presented here would provide generalizations of those given in earlier works.
Bio-oil fractionation and condensation
Brown, Robert C; Jones, Samuel T; Pollard, Anthony
2013-07-02
A method of fractionating bio-oil vapors which involves providing bio-oil vapors comprising bio-oil constituents is described. The bio-oil vapors are cooled in a first stage which comprises a condenser having passages for the bio-oil separated by a heat conducting wall from passages for a coolant. The coolant in the condenser of the first stage is maintained at a substantially constant temperature, set at a temperature in the range of 75 to 100.degree. C., to condense a first liquid fraction of liquefied bio-oil constituents in the condenser of the first stage. The first liquid fraction of liquified bio-oil constituents from the condenser in the first stage is collected. Also described are steps for subsequently recovering further liquid fractions of liquefied bio-oil constituents. Particular compositions of bio-oil condensation products are also described.
Symmetric, discrete fractional splines and Gabor systems
DEFF Research Database (Denmark)
Søndergaard, Peter Lempel
2006-01-01
In this paper we consider fractional splines as windows for Gabor frames. We introduce two new types of symmetric, fractional splines in addition to one found by Unser and Blu. For the finite, discrete case we present two families of splines: One is created by sampling and periodizing the continu......In this paper we consider fractional splines as windows for Gabor frames. We introduce two new types of symmetric, fractional splines in addition to one found by Unser and Blu. For the finite, discrete case we present two families of splines: One is created by sampling and periodizing...... the continuous splines, and one is a truly finite, discrete construction. We discuss the properties of these splines and their usefulness as windows for Gabor frames and Wilson bases....
Impulsive fractional differential inclusions with infinite delay
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Khalida Aissani
2013-11-01
Full Text Available In this article, we apply Bohnenblust-Karlin's fixed point theorem to prove the existence of mild solutions for a class of impulsive fractional equations inclusions with infinite delay. An example is given to illustrate the theory.
Fractional Calculus and -Valently Starlike Functions
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Özkan Öznur
2009-01-01
Full Text Available Abstract In this investigation, the authors prove coefficient bounds, distortion inequalities for fractional calculus of a family of multivalent functions with negative coefficients, which is defined by means of a certain nonhomogenous Cauchy-Euler differential equation.
Fractional diffusion equations and anomalous diffusion
Evangelista, Luiz Roberto
2018-01-01
Anomalous diffusion has been detected in a wide variety of scenarios, from fractal media, systems with memory, transport processes in porous media, to fluctuations of financial markets, tumour growth, and complex fluids. Providing a contemporary treatment of this process, this book examines the recent literature on anomalous diffusion and covers a rich class of problems in which surface effects are important, offering detailed mathematical tools of usual and fractional calculus for a wide audience of scientists and graduate students in physics, mathematics, chemistry and engineering. Including the basic mathematical tools needed to understand the rules for operating with the fractional derivatives and fractional differential equations, this self-contained text presents the possibility of using fractional diffusion equations with anomalous diffusion phenomena to propose powerful mathematical models for a large variety of fundamental and practical problems in a fast-growing field of research.
Early Predictors of Middle School Fraction Knowledge
Bailey, Drew H.; Siegler, Robert S.; Geary, David C.
2014-01-01
Recent findings that earlier fraction knowledge predicts later mathematics achievement raise the question of what predicts later fraction knowledge. Analyses of longitudinal data indicated that whole number magnitude knowledge in first grade predicted knowledge of fraction magnitudes in middle school, controlling for whole number arithmetic proficiency, domain general cognitive abilities, parental income and education, race, and gender. Similarly, knowledge of whole number arithmetic in first grade predicted knowledge of fraction arithmetic in middle school, controlling for whole number magnitude knowledge in first grade and the other control variables. In contrast, neither type of early whole number knowledge uniquely predicted middle school reading achievement. We discuss the implications of these findings for theories of numerical development and for improving mathematics learning. PMID:24576209
The Fractional Orthogonal Difference with Applications
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Enno Diekema
2015-06-01
Full Text Available This paper is a follow-up of a previous paper of the author published in Mathematics journal in 2015, which treats the so-called continuous fractional orthogonal derivative. In this paper, we treat the discrete case using the fractional orthogonal difference. The theory is illustrated with an application of a fractional differentiating filter. In particular, graphs are presented of the absolutel value of the modulus of the frequency response. These make clear that for a good insight into the behavior of a fractional differentiating filter, one has to look for the modulus of its frequency response in a log-log plot, rather than for plots in the time domain.
Hydrocarbon fractions. Aromatic determination by mass spectrometry
International Nuclear Information System (INIS)
Anon.
Analysis of hydrocarbon fractions by mass spectrometry using low energy electrons, for determination of aromatic hydrocarbons repartition, suitable for fraction with the following properties: boiling point up to 320 0 C, whithout olefine, sulfur content up to 0.1 per cent, boiling range up to 100 0 C, if the final temperature is 200 0 C, and up to 50 0 C, if over 200 0 C [fr
A quadri-constant fraction discriminator
International Nuclear Information System (INIS)
Wang Wei; Gu Zhongdao
1992-01-01
A quad Constant Fraction (Amplitude and Rise Time Compensation) Discriminator Circuit is described, which is based on the ECL high-speed dual comparator AD 9687. The CFD (ARCD) is of the constant fraction timing type (the amplitude and rise time compensation timing type) employing a leading edge discriminator to eliminate error triggers caused by noises. A timing walk measurement indicates a timing walk of less than +- 150 ps from -50 mV to -5 V
Deformable fractional derivative and its applications
Ahuja, Priyanka; Zulfeqarr, Fahed; Ujlayan, Amit
2017-10-01
In this paper, we introduce an application of recently proposed deformable derivative which is equivalent to ordinary derivative in the sense that one implies other. The deformable derivative is defined using limit approach as ordinary derivative. Thus it could also be regarded as fractional derivative. The simple nature of this definition allows us for the extension of some classical theorems in calculus like the Rolles, Mean Value and Extended Mean Value theorems. As a theoritical application some fractional differentiable equations are solved.
Unanswered Quibbles with Fractional Reserve Free Banking
Bagus, Philipp; Howden, David
2011-01-01
In this article we reply to George Selgin’s counterarguments to our article “Fractional Reserve Free Banking: Some Quibbles”. Selgin regards holding cash as saving while we focus on the real savings necessary to maintain investment projects. Real savings are unconsumed real income. Variations in real savings are not necessarily equal to variations in cash holdings. We show that a coordinated credit expansion in a fractional reserve free banking (FRFB) system is possible and that precautionary...
LATERAL SURVIVAL: AN OT ACCOUNT
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Moira Yip
2004-12-01
Full Text Available When laterals are the targets of phonological processes, laterality may or may not survive. In a fixed feature geometry, [lateral] should be lost if its superordinate node is eliminated by either the spreading of a neighbouring node, or by coda neutralization. So if [lateral] is under Coronal (Blevins 1994, it should be lost under Place assimilation, and if [lateral] is under Sonorant Voicing (Rice & Avery 1991 it should be lost by rules that spread voicing. Yet in some languages lateral survives such spreading intact. Facts like these argue against a universal attachment of [lateral] under either Coronal or Sonorant Voicing, and in favour of an account in terms of markedness constraints on feature-co-occurrence (Padgett 2000. The core of an OT account is that IFIDENTLAT is ranked above whatever causes neutralization, such as SHARE-F or *CODAF. laterality will survive. If these rankings are reversed, we derive languages in which laterality is lost. The other significant factor is markedness. High-ranked feature co-occurrence constraints like *LATDORSAL can block spreading from affecting laterals at all.
International Nuclear Information System (INIS)
Wiltshire, Kirsty L.; Ward, Iain G.; Swallow, Carol; Oza, Amit M.; Cummings, Bernard; Pond, Gregory R.; Catton, Pamela; Kim, John; Ringash, Jolie; Wong, Chong S.; Wong, Rebecca; Siu, Lillian L.; Moore, Malcolm; Brierley, James
2006-01-01
Purpose: Three Phase II studies of preoperative radiotherapy and concurrent 5FU chemotherapy were undertaken. The primary endpoints were acute toxicity and pathologic complete response rate (pCR). Secondary endpoints were local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS). Methods and Materials: A total of 134 patients with adenocarcinoma of the rectum (clinical T3/T4 or N1/N2) were treated. The initial cohort received 40 Gy in 20 fractions, the second 46 Gy in 23 fractions, and the third 50 Gy in 25 fractions. 5FU (225 mg/m 2 /day) was given continuously throughout radiotherapy. A total of 121 patients underwent surgical resection. Results: Treatment was well tolerated. Grade 3/4 acute toxicity was observed in 13%, 4%, and 14% of patients in the 40 Gy, 46 Gy, and 50 Gy cohorts, respectively (p = 0.20). pCR was documented in 15%, 23%, and 33% of patients, respectively (p = 0.07). The 2-year actuarial LRFS was 72%, 90%, and 89% (p = 0.02); DFS was 62%, 84%, and 78% (p = 0.02); and OS was 72%, 94%, and 92%, respectively (p = 0.03). Conclusions: All treatment schedules were well tolerated. There was a trend toward increased pCR with higher doses. A statistically significant increase in LRFS, DFS, and OS was seen with radiation doses of 46 Gy and greater, but there was no difference between 46 Gy and 50 Gy
Fractional Fick's law: the direct way
International Nuclear Information System (INIS)
Neel, M C; Abdennadher, A; Joelson, M
2007-01-01
Levy flights, which are Markovian continuous time random walks possibly accounting for extreme events, serve frequently as small-scale models for the spreading of matter in heterogeneous media. Among them, Brownian motion is a particular case where Fick's law holds: for a cloud of walkers, the flux is proportional to the gradient of the probability density of finding a particle at some place. Levy flights resemble Brownian motion, except that jump lengths are distributed according to an α-stable Levy law, possibly showing heavy tails and skewness. For α between 1 and 2, a fractional form of Fick's law is known to hold in infinite media: that the flux is proportional to a combination of fractional derivatives or the order of α - 1 of the density of walkers was obtained as a consequence of a fractional dispersion equation. We present a direct and natural proof of this result, based upon a novel definition of usual fractional derivatives, involving a convolution and a limiting process. Taking account of the thus obtained fractional Fick's law yields fractional dispersion equation for smooth densities. The method adapts to domains, limited by boundaries possibly implying non-trivial modifications to this equation
Generalized continued fractions and ergodic theory
International Nuclear Information System (INIS)
Pustyl'nikov, L D
2003-01-01
In this paper a new theory of generalized continued fractions is constructed and applied to numbers, multidimensional vectors belonging to a real space, and infinite-dimensional vectors with integral coordinates. The theory is based on a concept generalizing the procedure for constructing the classical continued fractions and substantially using ergodic theory. One of the versions of the theory is related to differential equations. In the finite-dimensional case the constructions thus introduced are used to solve problems posed by Weyl in analysis and number theory concerning estimates of trigonometric sums and of the remainder in the distribution law for the fractional parts of the values of a polynomial, and also the problem of characterizing algebraic and transcendental numbers with the use of generalized continued fractions. Infinite-dimensional generalized continued fractions are applied to estimate sums of Legendre symbols and to obtain new results in the classical problem of the distribution of quadratic residues and non-residues modulo a prime. In the course of constructing these continued fractions, an investigation is carried out of the ergodic properties of a class of infinite-dimensional dynamical systems which are also of independent interest
Maximizing Tumor Immunity With Fractionated Radiation
Energy Technology Data Exchange (ETDEWEB)
Schaue, Doerthe, E-mail: dschaue@mednet.ucla.edu [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); Ratikan, Josephine A.; Iwamoto, Keisuke S.; McBride, William H. [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States)
2012-07-15
Purpose: Technologic advances have led to increased clinical use of higher-sized fractions of radiation dose and higher total doses. How these modify the pathways involved in tumor cell death, normal tissue response, and signaling to the immune system has been inadequately explored. Here we ask how radiation dose and fraction size affect antitumor immunity, the suppression thereof, and how this might relate to tumor control. Methods and Materials: Mice bearing B16-OVA murine melanoma were treated with up to 15 Gy radiation given in various-size fractions, and tumor growth followed. The tumor-specific immune response in the spleen was assessed by interferon-{gamma} enzyme-linked immunospot (ELISPOT) assay with ovalbumin (OVA) as the surrogate tumor antigen and the contribution of regulatory T cells (Tregs) determined by the proportion of CD4{sup +}CD25{sup hi}Foxp3{sup +} T cells. Results: After single doses, tumor control increased with the size of radiation dose, as did the number of tumor-reactive T cells. This was offset at the highest dose by an increase in Treg representation. Fractionated treatment with medium-size radiation doses of 7.5 Gy/fraction gave the best tumor control and tumor immunity while maintaining low Treg numbers. Conclusions: Radiation can be an immune adjuvant, but the response varies with the size of dose per fraction. The ultimate challenge is to optimally integrate cancer immunotherapy into radiation therapy.
Isotopic fractionation of tritium in biological systems.
Le Goff, Pierre; Fromm, Michel; Vichot, Laurent; Badot, Pierre-Marie; Guétat, Philippe
2014-04-01
Isotopic fractionation of tritium is a highly relevant issue in radiation protection and requires certain radioecological considerations. Sound evaluation of this factor is indeed necessary to determine whether environmental compartments are enriched/depleted in tritium or if tritium is, on the contrary, isotopically well-distributed in a given system. The ubiquity of tritium and the standard analytical methods used to assay it may induce biases in both the measurement and the signification that is accorded to the so-called fractionation: based on an exhaustive review of the literature, we show how, sometimes large deviations may appear. It is shown that when comparing the non-exchangeable fraction of organically bound tritium (neOBT) to another fraction of tritium (e.g. tritiated water) the preparation of samples and the measurement of neOBT reported frequently led to underestimation of the ratio of tritium to hydrogen (T/H) in the non-exchangeable compartment by a factor of 5% to 50%. In the present study, corrections are proposed for most of the biological matrices studied so far. Nevertheless, the values of isotopic fractionation reported in the literature remain difficult to compare with each other, especially since the physical quantities and units often vary between authors. Some improvements are proposed to better define what should encompass the concepts of exchangeable and non-exchangeable fractions. Copyright © 2014 Elsevier Ltd. All rights reserved.
Maximizing Tumor Immunity With Fractionated Radiation
International Nuclear Information System (INIS)
Schaue, Dörthe; Ratikan, Josephine A.; Iwamoto, Keisuke S.; McBride, William H.
2012-01-01
Purpose: Technologic advances have led to increased clinical use of higher-sized fractions of radiation dose and higher total doses. How these modify the pathways involved in tumor cell death, normal tissue response, and signaling to the immune system has been inadequately explored. Here we ask how radiation dose and fraction size affect antitumor immunity, the suppression thereof, and how this might relate to tumor control. Methods and Materials: Mice bearing B16-OVA murine melanoma were treated with up to 15 Gy radiation given in various-size fractions, and tumor growth followed. The tumor-specific immune response in the spleen was assessed by interferon-γ enzyme-linked immunospot (ELISPOT) assay with ovalbumin (OVA) as the surrogate tumor antigen and the contribution of regulatory T cells (Tregs) determined by the proportion of CD4 + CD25 hi Foxp3 + T cells. Results: After single doses, tumor control increased with the size of radiation dose, as did the number of tumor-reactive T cells. This was offset at the highest dose by an increase in Treg representation. Fractionated treatment with medium-size radiation doses of 7.5 Gy/fraction gave the best tumor control and tumor immunity while maintaining low Treg numbers. Conclusions: Radiation can be an immune adjuvant, but the response varies with the size of dose per fraction. The ultimate challenge is to optimally integrate cancer immunotherapy into radiation therapy.
Statistical Methods for Conditional Survival Analysis.
Jung, Sin-Ho; Lee, Ho Yun; Chow, Shein-Chung
2017-11-29
We investigate the survival distribution of the patients who have survived over a certain time period. This is called a conditional survival distribution. In this paper, we show that one-sample estimation, two-sample comparison and regression analysis of conditional survival distributions can be conducted using the regular methods for unconditional survival distributions that are provided by the standard statistical software, such as SAS and SPSS. We conduct extensive simulations to evaluate the finite sample property of these conditional survival analysis methods. We illustrate these methods with real clinical data.
Characterization of Coconut Oil Fractions Obtained from Solvent Fractionation Using Acetone.
Sonwai, Sopark; Rungprasertphol, Poonyawee; Nantipipat, Nantinee; Tungvongcharoan, Satinee; Laiyangkoon, Nantikan
2017-09-01
This work was aimed to study the solvent fraction of coconut oil (CNO). The fatty acid and triacylglycerol compositions, solid fat content (SFC) and the crystallization properties of CNO and its solid and liquid fractions obtained from fractionation at different conditions were investigated using various techniques. CNO was dissolved in acetone (1:1 w/v) and left to crystallize isothermally at 10°C for 0.5, 1 and 2 h and at 12°C for 2, 3 and 6 h. The solid fractions contained significantly lower contents of saturated fatty acids of ≤ 10 carbon atoms but considerably higher contents of saturated fatty acids with > 12 carbon atoms with respect to those of CNO and the liquid fractions. They also contained higher contents of high-melting triacylglycerol species with carbon number ≥ 38. Because of this, the DSC crystallization onset temperatures and the crystallization peak temperatures of the solid fractions were higher than CNO and the liquid fractions. The SFC values of the solid fractions were significantly higher than CNO at all measuring temperatures before reaching 0% just below the body temperature with the fraction obtained at 12°C for 2 h exhibiting the highest SFC. On the contrary, the SFC values of the liquid fractions were lower than CNO. The crystallization duration exhibited strong influence on the solid fractions. There was no effect on the crystal polymorphic structure possibly because CNO has β'-2 as a stable polymorph. The enhanced SFC of the solid fractions would allow them to find use in food applications where a specific melting temperature is desired such as sophisticated confectionery fats, and the decreased SFC of the liquid fractions would provide them with a higher cold stability which would be useful during extended storage time.
SU-E-J-105: Stromal-Epithelial Responses to Fractionated Radiotherapy
Energy Technology Data Exchange (ETDEWEB)
Qayyum, M [Little Company of Mary Hospital, Ever Green Park, IL (United States)
2014-06-01
Purpose: The stromal-epithelial-cell interactions that are responsible for directing normal breast-tissue development and maintenance play a central role in the progression of breast cancer. In the present study, we developed three-dimensional (3-D) cell co-cultures used to study cancerous mammary cell responses to fractionated radiotherapy. In particular, we focused on the role of the reactive stroma in determining the therapeutic ratio for postsurgical treatment. Methods: Cancerous human mammary epithelial cells were cultured in a 3-D collagen matrix with human fibroblasts stimulated by various concentrations of transforming growth factor beta 1 (TGF-β1). These culture samples were designed to model the post-lumpectomy mammary stroma in the presence of residual cancer cells. We tracked over time the changes in medium stiffness, fibroblast-cell activation (conversion to cancer activated fibroblasts (CAF)), and proliferation of both cell types under a variety of fractionated radiotherapy protocols. Samples were exposed to 6 MV X-rays from a linear accelerator in daily fraction sizes of 90, 180 and 360 cGy over five days in a manner consistent with irradiation exposure during radiotherapy. Results: We found in fractionation studies with fibroblasts and CAF that higher doses per fraction may be more effective early on in deactivating cancer-harboring cellular environments. Higher-dose fraction schemes inhibit contractility in CAF and prevent differentiation of fibroblasts, thereby metabolically uncoupling tumor cells from their surrounding stroma. Yet, over a longer time period, the higher dose fractions may slow wound healing and increase ECM stiffening that could stimulate proliferation of surviving cancer cells. Conclusion: The findings suggest that dose escalation to the region with residual disease can deactivate the reactive stroma, thus minimizing the cancer promoting features of the cellular environment. Large-fraction irradiation may be used to sterilize
Thermal analysis of ice and glass transitions in insects that do and do not survive freezing.
Rozsypal, Jan; Moos, Martin; Šimek, Petr; Koštál, Vladimír
2018-03-01
Some insects rely on the strategy of freeze tolerance for winter survival. During freezing, extracellular body water transitions from the liquid to solid phase and cells undergo freeze-induced dehydration. Here we present results of a thermal analysis (from differential scanning calorimetry) of ice fraction dynamics during gradual cooling after inoculative freezing in variously acclimated larvae of two drosophilid flies, Drosophila melanogaster and Chymomyza costata. Although the species and variants ranged broadly between 0 and close to 100% survival of freezing, there were relatively small differences in ice fraction dynamics. For instance, the maximum ice fraction (IF max ) ranged between 67.9 and 77.7% total body water (TBW). The C. costata larvae showed statistically significant phenotypic shifts in parameters of ice fraction dynamics (melting point and IF max ) upon entry into diapause, cold-acclimation, and feeding on a proline-augmented diet. These differences were mostly driven by colligative effects of accumulated proline (ranging between 6 and 487 mmol.kg -1 TBW) and other metabolites. Our data suggest that these colligative effects per se do not represent a sufficient mechanistic explanation for high freeze tolerance observed in diapausing, cold-acclimated C. costata larvae. Instead, we hypothesize that accumulated proline exerts its protective role via a combination of mechanisms. Specifically, we found a tight association between proline-induced stimulation of glass transition in partially-frozen body liquids (vitrification) and survival of cryopreservation in liquid nitrogen. © 2018. Published by The Company of Biologists Ltd.
expansion method for solving nonlinear space–time fractional ...
Indian Academy of Sciences (India)
2016-07-06
Jul 6, 2016 ... -expansion method for solving fractional differential equations based on a fractional complex transform. We apply this method for solving space–time fractional Cahn–Allen equation and space–time fractional Klein–Gordon equation. The fractional derivatives are described in the sense of modified ...
Radiotherapy for esophageal carcinoma: dose, response and survival
Directory of Open Access Journals (Sweden)
Luo Y
2017-12-01
Full Text Available Yijun Luo,1,* Qingfeng Mao,2,3,* Xiaoli Wang,1 Jinming Yu,3 Minghuan Li3 1Department of Oncology, The People’s Hospital of Jiangxi, Nanchang, 2School of Medical and Life Sciences, University of Jinan-Shandong Academy of Medical Sciences, 3Department of Radiation Oncology and Radiology, Shandong Cancer Hospital Affiliated to Shandong University, Jinan, China *These authors contributed equally to this work Abstract: Esophageal cancer (EC is an extremely aggressive, lethal malignancy that is increasing in incidence worldwide. At present, definitive chemoradiotherapy is accepted as the standard treatment for locally advanced EC. The EC guidelines recommend a radiation dose of 50.4 Gy for definitive treatment, yet the outcomes for patients who have received standard-dose radiotherapy remain unsatisfactory. However, some studies indicate that a higher radiation dose could improve local tumor control, and may also confer survival benefits. Some studies, however, suggest that high-dose radiotherapy does not bring survival benefit. The available data show that most failures occurred in the gross target volume (especially in the primary tumor after definitive chemoradiation. Based on those studies, we hypothesize that at least for some patients, more intense local therapy may lead to better local control and survival. The aim of this review is to evaluate the radiation dose, fractionation strategies, and predictive factors of response to therapy in functional imaging for definitive chemoradiotherapy in esophageal carcinoma, with an emphasis on seeking the predictive model of response to CRT and trying to individualize the radiation dose for EC patients. Keywords: esophageal cancer, radiation dose, altered fractionation, predictive factors, individualization
Xu, Kaixuan; Wang, Jun
2017-02-01
In this paper, recently introduced permutation entropy and sample entropy are further developed to the fractional cases, weighted fractional permutation entropy (WFPE) and fractional sample entropy (FSE). The fractional order generalization of information entropy is utilized in the above two complexity approaches, to detect the statistical characteristics of fractional order information in complex systems. The effectiveness analysis of proposed methods on the synthetic data and the real-world data reveals that tuning the fractional order allows a high sensitivity and more accurate characterization to the signal evolution, which is useful in describing the dynamics of complex systems. Moreover, the numerical research on nonlinear complexity behaviors is compared between the returns series of Potts financial model and the actual stock markets. And the empirical results confirm the feasibility of the proposed model.
Fractional order differentiation by integration: An application to fractional linear systems
Liu, Dayan
2013-02-04
In this article, we propose a robust method to compute the output of a fractional linear system defined through a linear fractional differential equation (FDE) with time-varying coefficients, where the input can be noisy. We firstly introduce an estimator of the fractional derivative of an unknown signal, which is defined by an integral formula obtained by calculating the fractional derivative of a truncated Jacobi polynomial series expansion. We then approximate the FDE by applying to each fractional derivative this formal algebraic integral estimator. Consequently, the fractional derivatives of the solution are applied on the used Jacobi polynomials and then we need to identify the unknown coefficients of the truncated series expansion of the solution. Modulating functions method is used to estimate these coefficients by solving a linear system issued from the approximated FDE and some initial conditions. A numerical result is given to confirm the reliability of the proposed method. © 2013 IFAC.
Particle Simulation of Fractional Diffusion Equations
Allouch, Samer
2017-07-12
This work explores different particle-based approaches to the simulation of one-dimensional fractional subdiffusion equations in unbounded domains. We rely on smooth particle approximations, and consider four methods for estimating the fractional diffusion term. The first method is based on direct differentiation of the particle representation, it follows the Riesz definition of the fractional derivative and results in a non-conservative scheme. The other three methods follow the particle strength exchange (PSE) methodology and are by construction conservative, in the sense that the total particle strength is time invariant. The first PSE algorithm is based on using direct differentiation to estimate the fractional diffusion flux, and exploiting the resulting estimates in an integral representation of the divergence operator. Meanwhile, the second one relies on the regularized Riesz representation of the fractional diffusion term to derive a suitable interaction formula acting directly on the particle representation of the diffusing field. A third PSE construction is considered that exploits the Green\\'s function of the fractional diffusion equation. The performance of all four approaches is assessed for the case of a one-dimensional diffusion equation with constant diffusivity. This enables us to take advantage of known analytical solutions, and consequently conduct a detailed analysis of the performance of the methods. This includes a quantitative study of the various sources of error, namely filtering, quadrature, domain truncation, and time integration, as well as a space and time self-convergence analysis. These analyses are conducted for different values of the order of the fractional derivatives, and computational experiences are used to gain insight that can be used for generalization of the present constructions.
Abuteen, Eman; Freihat, Asad; Al-Smadi, Mohammed; Khalil, Hammad; Khan, Rahmat Ali
2017-01-01
This analysis proposes an analytical-numerical approach for providing solutions of a class of nonlinear fractional Klein-Gordon equation subjected to appropriate initial conditions in Caputo sense by using the Fractional Reduced Differential Transform Method (FRDTM). This technique provides the solutions very accurately and efficiently in convergent series formula with easily computable coefficients. The behavior of the approximate series solution for different values of fractional-order "a" ...
Stage at diagnosis and ovarian cancer survival
DEFF Research Database (Denmark)
Maringe, Camille; Walters, Sarah; Butler, John
2012-01-01
We investigate what role stage at diagnosis bears in international differences in ovarian cancer survival.......We investigate what role stage at diagnosis bears in international differences in ovarian cancer survival....
Probability of Survival Decision Aid (PSDA)
National Research Council Canada - National Science Library
Xu, Xiaojiang; Amin, Mitesh; Santee, William R
2008-01-01
A Probability of Survival Decision Aid (PSDA) is developed to predict survival time for hypothermia and dehydration during prolonged exposure at sea in both air and water for a wide range of environmental conditions...
Life-Cycle Models for Survivable Systems
National Research Council Canada - National Science Library
Linger, Richard
2002-01-01
.... Current software development life-cycle models are not focused on creating survivable systems, and exhibit shortcomings when the goal is to develop systems with a high degree of assurance of survivability...
N U+02BC Doye, Ibrahima
2018-02-13
In this paper, we propose a robust fractional-order proportional-integral U+0028 FOPI U+0029 observer for the synchronization of nonlinear fractional-order chaotic systems. The convergence of the observer is proved, and sufficient conditions are derived in terms of linear matrix inequalities U+0028 LMIs U+0029 approach by using an indirect Lyapunov method. The proposed U+0028 FOPI U+0029 observer is robust against Lipschitz additive nonlinear uncertainty. It is also compared to the fractional-order proportional U+0028 FOP U+0029 observer and its performance is illustrated through simulations done on the fractional-order chaotic Lorenz system.
Directory of Open Access Journals (Sweden)
J. Vanterler da C. Sousa
2018-01-01
Full Text Available We introduce a truncated $M$-fractional derivative type for $\\alpha$-differentiable functions that generalizes four other fractional derivatives types recently introduced by Khalil et al., Katugampola and Sousa et al., the so-called conformable fractional derivative, alternative fractional derivative, generalized alternative fractional derivative and $M$-fractional derivative, respectively. We denote this new differential operator by $_{i}\\mathscr{D}_{M}^{\\alpha,\\beta }$, where the parameter $\\alpha$, associated with the order of the derivative is such that $ 0 <\\alpha<1 $, $\\beta>0$ and $ M $ is the notation to designate that the function to be derived involves the truncated Mittag-Leffler function with one parameter.The definition of this truncated $M$-fractional derivative type satisfies the properties of the integer-order calculus. We also present, the respective fractional integral from which emerges, as a natural consequence, the result, which can be interpreted as an inverse property. Finally, we obtain the analytical solution of the $M$-fractional heat equation and present a graphical analysis.
Directory of Open Access Journals (Sweden)
Hamid A. Jalab
2014-01-01
Full Text Available The interest in using fractional mask operators based on fractional calculus operators has grown for image denoising. Denoising is one of the most fundamental image restoration problems in computer vision and image processing. This paper proposes an image denoising algorithm based on convex solution of fractional heat equation with regularized fractional power parameters. The performances of the proposed algorithms were evaluated by computing the PSNR, using different types of images. Experiments according to visual perception and the peak signal to noise ratio values show that the improvements in the denoising process are competent with the standard Gaussian filter and Wiener filter.
Socioeconomic position and survival after cervical cancer
DEFF Research Database (Denmark)
Ibfelt, E H; Kjær, S K; Høgdall, C
2013-01-01
In an attempt to decrease social disparities in cancer survival, it is important to consider the mechanisms by which socioeconomic position influences cancer prognosis. We aimed to investigate whether any associations between socioeconomic factors and survival after cervical cancer could be expla......In an attempt to decrease social disparities in cancer survival, it is important to consider the mechanisms by which socioeconomic position influences cancer prognosis. We aimed to investigate whether any associations between socioeconomic factors and survival after cervical cancer could...
Starvation-Survival in Haloarchaea
Directory of Open Access Journals (Sweden)
Yaicha D. Winters
2015-11-01
Full Text Available Recent studies claiming to revive ancient microorganisms trapped in fluid inclusions in halite have warranted an investigation of long-term microbial persistence. While starvation-survival is widely reported for bacteria, it is less well known for halophilic archaea—microorganisms likely to be trapped in ancient salt crystals. To better understand microbial survival in fluid inclusions in ancient evaporites, laboratory experiments were designed to simulate growth of halophilic archaea under media-rich conditions, complete nutrient deprivation, and a controlled substrate condition (glycerol-rich and record their responses. Haloarchaea used for this work included Hbt. salinarum and isolate DV582A-1 (genus Haloterrigena sub-cultured from 34 kyear Death Valley salt. Hbt. salinarum and DV582A-1 reacted to nutrient limitation with morphological and population changes. Starved populations increased and most cells converted from rods to small cocci within 56 days of nutrient deprivation. The exact timing of starvation adaptations and the physical transformations differed between species, populations of the same species, and cells of the same population. This is the first study to report the timing of starvation strategies for Hbt. salinarum and DV582A-1. The morphological states in these experiments may allow differentiation between cells trapped with adequate nutrients (represented here by early stages in nutrient-rich media from cells trapped without nutrients (represented here by experimental starvation in ancient salt. The hypothesis that glycerol, leaked from Dunaliella, provides nutrients for the survival of haloarchaea trapped in fluid inclusions in ancient halite, is also tested. Hbt. salinarum and DV582A-1 were exposed to a mixture of lysed and intact Dunaliella for 56 days. The ability of these organisms to utilize glycerol from Dunaliella cells was assessed by documenting population growth, cell length, and cell morphology. Hbt. salinarum
Starvation-Survival in Haloarchaea.
Winters, Yaicha D; Lowenstein, Tim K; Timofeeff, Michael N
2015-11-12
Recent studies claiming to revive ancient microorganisms trapped in fluid inclusions in halite have warranted an investigation of long-term microbial persistence. While starvation-survival is widely reported for bacteria, it is less well known for halophilic archaea-microorganisms likely to be trapped in ancient salt crystals. To better understand microbial survival in fluid inclusions in ancient evaporites, laboratory experiments were designed to simulate growth of halophilic archaea under media-rich conditions, complete nutrient deprivation, and a controlled substrate condition (glycerol-rich) and record their responses. Haloarchaea used for this work included Hbt. salinarum and isolate DV582A-1 (genus Haloterrigena) sub-cultured from 34 kyear Death Valley salt. Hbt. salinarum and DV582A-1 reacted to nutrient limitation with morphological and population changes. Starved populations increased and most cells converted from rods to small cocci within 56 days of nutrient deprivation. The exact timing of starvation adaptations and the physical transformations differed between species, populations of the same species, and cells of the same population. This is the first study to report the timing of starvation strategies for Hbt. salinarum and DV582A-1. The morphological states in these experiments may allow differentiation between cells trapped with adequate nutrients (represented here by early stages in nutrient-rich media) from cells trapped without nutrients (represented here by experimental starvation) in ancient salt. The hypothesis that glycerol, leaked from Dunaliella, provides nutrients for the survival of haloarchaea trapped in fluid inclusions in ancient halite, is also tested. Hbt. salinarum and DV582A-1 were exposed to a mixture of lysed and intact Dunaliella for 56 days. The ability of these organisms to utilize glycerol from Dunaliella cells was assessed by documenting population growth, cell length, and cell morphology. Hbt. salinarum and DV582A-1
Survival analysis following dynamic randomization
Directory of Open Access Journals (Sweden)
Xiaolong Luo
2016-08-01
Full Text Available In this paper, we propose a method to analyze survival data from a clinical trial that utilizes a dynamic randomization for subject enrollment. The method directly accounts for dynamic subject randomization process using a marked point process (MPP. Its corresponding martingale process is used to formulate an equation for estimating the treatment effect size and for hypothesis testing. We perform simulation analyses to evaluate the outcomes of the proposed method as well as the conventional log rank method and re-randomized testing procedure.
Traumatic atlantooccipital dislocation with survival.
Woodring, J H; Selke, A C; Duff, D E
1981-07-01
Traumatic atlantooccipital dislocation is generally considered incompatible with life. However, there have been isolated survivals from this injury, and a few patients initially have minimal neurologic deficits disproportionate to the gravity of their injury, a feature that has not been adequately stressed. The potentially catastrophic results of delayed therapy make early radiographic detection imperative. Marked retropharyngeal soft-tissue swelling, an abnormal basion-odontoid alignment, and posterior displacement of the atlas are diagnostic of anterior atlantooccipital dislocation. In the more uncommon posterior atlantooccipital dislocation an abnormal basion-odontoid alignment associated with marked soft-tissue swelling should suggest the correct diagnosis. Conventional tomography can be confirmatory.
Designing an automated blood fractionation system.
McQuillan, Adrian C; Sales, Sean D
2008-04-01
UK Biobank will be collecting blood samples from a cohort of 500 000 volunteers and it is expected that the rate of collection will peak at approximately 3000 blood collection tubes per day. These samples need to be prepared for long-term storage. It is not considered practical to manually process this quantity of samples so an automated blood fractionation system is required. Principles of industrial automation were applied to the blood fractionation process leading to the requirement of developing a vision system to identify the blood fractions within the blood collection tube so that the fractions can be accurately aspirated and dispensed into micro-tubes. A prototype was manufactured and tested on a range of human blood samples collected in different tube types. A specially designed vision system was capable of accurately measuring the position of the plasma meniscus, plasma/buffy coat interface and the red cells/buffy coat interface within a vacutainer. A rack of 24 vacutainers could be processed in blood fractionation system offers a solution to the problem of processing human blood samples collected in vacutainers in a consistent manner and provides a means of ensuring data and sample integrity.
Quality assurance in fractionated stereotactic radiotherapy
International Nuclear Information System (INIS)
Warrington, A.P.; Laing, R.W.; Brada, M.
1994-01-01
The recent development of fractionated stereotactic radiotherapy (SRT), which utilises the relocatable Gill-Thomas-Cosman frame (GTC 'repeat localiser'), requires comprehensive quality assurance (QA). This paper focuses on those QA procedures particularly relevant to fractionated SRT treatments, and which have been derived from the technique used at the Royal Marsden Hospital. They primarily relate to the following: (i) GTC frame fitting, initially in the mould room, and then at each imaging session and treatment fraction; (ii) checking of the linear accelerator beam geometry and alignment lasers; and (iii) setting up of the patient for each fraction of treatment. The precision of the fractionated technique therefore depends on monitoring the GTC frame relocation at each fitting, checking the accuracy of the radiation isocentre of the treatment unit, its coincidence with the patient alignment lasers and the adjustments required to set the patient up accurately. The results of our quality control checks show that setting up to a mean radiation isocentre using precisely set-up alignment lasers can be achievable to within 1 mm accuracy. When this is combined with a mean GTC frame relocatability of 1 mm on the patient, a 2-mm allowance between the prescribed isodose surface and the defined target volume is a realistic safety margin for this technique
Current Status of Fractional Laser Resurfacing.
Carniol, Paul J; Hamilton, Mark M; Carniol, Eric T
2015-01-01
Fractional lasers were first developed based on observations of lasers designed for hair transplantation. In 2007, ablative fractional laser resurfacing was introduced. The fractionation allowed deeper tissue penetration, leading to greater tissue contraction, collagen production and tissue remodeling. Since then, fractional erbium:YAG resurfacing lasers have also been introduced. These lasers have yielded excellent results in treating photoaging, acne scarring, and dyschromia. With the adjustment of microspot density, pulse duration, number of passes, and fluence, the surgeon can adjust the treatment effects. These lasers have allowed surgeons to treat patients with higher Fitzpatrick skin types (types IV to VI) and greater individualize treatments to various facial subunits. Immunohistochemical analysis has demonstrated remodeling effects of the tissues for several months, producing longer lasting results. Adjuvant treatments are also under investigation, including concomitant face-lift, product deposition, and platelet-rich plasma. Finally, there is a short recovery time from treatment with these lasers, allowing patients to resume regular activities more quickly. Although there is a relatively high safety profile for ablative fractionated lasers, surgeons should be aware of the limitations of specific treatments and the associated risks and complications.
Intra-fraction motion of larynx radiotherapy
Durmus, Ismail Faruk; Tas, Bora
2018-02-01
In early stage laryngeal radiotherapy, movement is an important factor. Thyroid cartilage can move from swallowing, breathing, sound and reflexes. The effects of this motion on the target volume (PTV) during treatment were examined. In our study, the target volume movement during the treatment for this purpose was examined. Thus, setup margins are re-evaluated and patient-based PTV margins are determined. Intrafraction CBCT was scanned in 246 fractions for 14 patients. During the treatment, the amount of deviation which could be lateral, vertical and longitudinal axis was determined. ≤ ± 0.1cm deviation; 237 fractions in the lateral direction, 202 fractions in the longitudinal direction, 185 fractions in the vertical direction. The maximum deviation values were found in the longitudinal direction. Intrafraction guide in laryngeal radiotherapy; we are sure of the correctness of the treatment, the target volume is to adjust the margin and dose more precisely, we control the maximum deviation of the target volume for each fraction. Although the image quality of intrafraction-CBCT scans was lower than the image quality of planning CT, they showed sufficient contrast for this work.
Oscillation results for certain fractional difference equations
Directory of Open Access Journals (Sweden)
Zhiyun WANG
2017-08-01
Full Text Available Fractional calculus is a theory that studies the properties and application of arbitrary order differentiation and integration. It can describe the physical properties of some systems more accurately, and better adapt to changes in the system, playing an important role in many fields. For example, it can describe the process of tumor growth (growth stimulation and growth inhibition in biomedical science. The oscillation of solutions of two kinds of fractional difference equations is studied, mainly using the proof by contradiction, that is, assuming the equation has a nonstationary solution. For the first kind of equation, the function symbol is firstly determined, and by constructing the Riccati function, the difference is calculated. Then the condition of the function is used to satisfy the contradiction, that is, the assumption is false, which verifies the oscillation of the solution. For the second kind of equation with initial condition, the equivalent fractional sum form of the fractional difference equation are firstly proved. With considering 0<α≤1 and α>1, respectively, by using the properties of Stirling formula and factorial function, the contradictory is got through enhanced processing, namely the assuming is not established, and the sufficient condition for the bounded solutions of the fractional difference equation is obtained. The above results will optimize the relevant conclusions and enrich the relevant results. The results are applied to the specific equations, and the oscillation of the solutions of equations is proved.
Long-term survival after perforated diverticulitis
J. Vermeulen (Jan); M.P. Gosselink (Martijn Pieter); W.C.J. Hop (Wim); E. van der Harst (Erwin); B.E. Hansen (Bettina); G.H.H. Mannaerts (Guido); P-P. Coene (Peter Paul); W.F. Weidema (Wibo); J.F. Lange (Johan)
2011-01-01
textabstractAim: Short-term survival after emergency surgery for perforated diverticulitis is poor. Less is known about long-term survival. The aims of this study were to evaluate long-term survival after discharge from hospital and to identify factors associated with prognosis. Method: All patients
Surviving the crash: T-cell homeostasis
Indian Academy of Sciences (India)
TOSHIBA
Spatial and temporal elements. – Cellular sites for the integration of cell death and survival cues. – Spatial regulation of Notch activity for cell survival. Page 4. Cell survival is determined by the availability and uptake of nutrients live dead. Activated T-cells. T-cells. Page 5. dead wildtype. Bax active -6A7. Nucleus – H33342.
46 CFR 133.105 - Survival craft.
2010-10-01
... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft. 133.105 Section 133.105 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS LIFESAVING SYSTEMS Requirements for All OSVs § 133.105 Survival craft. (a) Each survival craft must be approved and equipped as...
46 CFR 199.201 - Survival craft.
2010-10-01
... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft. 199.201 Section 199.201 Shipping COAST... craft. (a) Each survival craft must be approved and equipped as follows: (1) Each lifeboat must be... addition to the survival craft required in paragraph (b)(1) of this section, additional liferafts must be...
46 CFR 199.261 - Survival craft.
2010-10-01
... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft. 199.261 Section 199.261 Shipping COAST... SYSTEMS FOR CERTAIN INSPECTED VESSELS Additional Requirements for Cargo Vessels § 199.261 Survival craft. (a) Each survival craft must be approved and equipped as follows: (1) Each lifeboat must be a totally...
Pharmacological Effects of a Fraction of the Methanolic Extract of ...
African Journals Online (AJOL)
MEPAF) were investigated. The fractions were obtained by subjecting the MEPAF to accelerated gradient column and Thin-Layer chromatography (TLC). Nine (9) fractions were obtained based on their retention factor (R ). One of the fractions, ...
International Nuclear Information System (INIS)
Wu Shaoxiong; Chua, Daniel T.T.; Deng Meiling; Zhao Chong; Li Fengyan; Sham, Jonathan S.T.; Wang Hanyu; Bao Yong; Gao Yuanhong; Zeng Zhifan
2007-01-01
Purpose: Local recurrence remains one of the major causes of failure in nasopharyngeal carcinoma (NPC). Stereotactic radiosurgery and fractionated stereotactic radiation therapy (FSRT) have recently evolved as a salvage option of NPC. This study was conducted to review the treatment outcome after FSRT for NPC. Methods and Materials: Between September 1999 and December 2005, 90 patients with persistent (Group 1: n = 34, relapse within 6 months of RT) or recurrent (Group 2: n = 56, relapse beyond 6 months) NPC received FSRT using multiple noncoplanar arcs of 8-MV photon to the target. Median FSRT dose was 18 Gy in three fractions (Group 1) or 48 Gy in six fractions (Group 2). Median follow-up was 20.3 months. Results: Complete response rate after FSRT was 66% for Group 1 and 63% for Group 2. One-, 2-, and 3-year disease-specific survival (DSS) and progression-free survival (PFS) rates for all patients were 82.6%, 74.8%, 57.5%, and 72.9%, 60.4%, 54.5%, respectively. Three-year local failure-free survival, DSS, and PFS rates were 89.4%, 80.7%, and 72.3% for Group 1, and 75.1%, 45.9%, and 42.9% for Group 2, respectively. Multivariate analysis showed that recurrent disease and large tumor volume were independent factors that predicted poorer DSS and PFS. Seventeen patients developed late complications, including 2 with fatal hemorrhage. Conclusions: Our results indicate that FSRT is effective for patients with persistent and recurrent NPC. Compared with reported results of radiosurgery, FSRT provides satisfactory tumor control and survival with a lower risk of complications and it may be a better treatment for local failures of NPC
International Nuclear Information System (INIS)
Graham, P.H.; Bucci, J.; Browne, L.
2010-01-01
Purpose: The present study compared the intracranial control rate and quality of life for two radiation fractionation schemes for cerebral metastases. Methods and Materials: A total of 113 patients with a Eastern Cooperative Oncology Group performance status 2 months), absent, or concurrent presentation of extracranial disease were randomized to 40 Gy in 20 twice-daily fractions (Arm A) or 20 Gy in four daily fractions (Arm B), stratified by resection status. The European Organization for Research and Treatment of Cancer Quality of Life 30-item questionnaire was administered monthly during Year 1, bimonthly during Year 2, and then every 6 months to Year 5. Results: The patient age range was 28-83 years (mean 62). Of the 113 patients, 41 had undergone surgical resection, and 74 patients had extracranial disease (31 concurrent and 43 stable). The median survival time was 6.1 months in Arm A and 6.6 months in Arm B, and the overall 5-year survival rate was 3.5%. Intracranial progression occurred in 44% of Arm A and 64% of Arm B patients (p = .03). Salvage surgery or radiotherapy was used in 4% of Arm A patients and 21% of Arm B patients (p = .004). Death was attributed to central nervous system progression in 32% of patients in Arm A and 52% of patients in Arm B (p = .03). The toxicity was minimal, with a minor increase in short-term cutaneous reactions in Arm A. The patients' quality of life was not impaired by the more intense treatment in Arm A. Conclusion: Intracranial disease control was improved and the quality of life was maintained with 40 Gy in 20 twice-daily fractions. This schema should be considered for better prognosis subgroups of patients with cerebral metastases.
Error analysis of pupils in calculating with fractions
Uranič, Petra
2016-01-01
In this thesis I examine the correlation between the frequency of errors that seventh grade pupils make in their calculations with fractions and their level of understanding of fractions. Fractions are a relevant and demanding theme in the mathematics curriculum. Although we use fractions on a daily basis, pupils find learning fractions to be very difficult. They generally do not struggle with the concept of fractions itself, but they frequently have problems with mathematical operations ...
Fractional virus epidemic model on financial networks
Directory of Open Access Journals (Sweden)
Balci Mehmet Ali
2016-01-01
Full Text Available In this study, we present an epidemic model that characterizes the behavior of a financial network of globally operating stock markets. Since the long time series have a global memory effect, we represent our model by using the fractional calculus. This model operates on a network, where vertices are the stock markets and edges are constructed by the correlation distances. Thereafter, we find an analytical solution to commensurate system and use the well-known differential transform method to obtain the solution of incommensurate system of fractional differential equations. Our findings are confirmed and complemented by the data set of the relevant stock markets between 2006 and 2016. Rather than the hypothetical values, we use the Hurst Exponent of each time series to approximate the fraction size and graph theoretical concepts to obtain the variables.
Measurement of Tau Lepton Branching Fractions
Energy Technology Data Exchange (ETDEWEB)
Nicol, N.
2003-12-19
We present {tau}{sup -} lepton branching fraction measurements based on data from the TPC/Two-Gamma detector at PEP. Using a sample of {tau}{sup -} {yields} {nu}{sub {tau}}K{sup -}{pi}{sup +}{pi}{sup -} events, we examine the resonance structure of the K{sup -}{pi}{sup +}{pi}{sup -} system and obtain the first measurements of branching fractions for {tau}{sup -} {yields} {nu}{sub {tau}}K{sub 1}{sup -}(1270) and {tau}{sup -} {yields} {nu}{sub {tau}}K{sub 1}{sup -}(1400). We also describe a complete set of branching fraction measurements in which all the decays of the {tau}{sup -} lepton are separated into classes defined by the identities of the charged particles and an estimate of the number of neutrals. This is the first such global measurement with decay classes defined by the four possible charged particle species, e, {mu}, {pi}, and K.
On the solution of fractional evolution equations
International Nuclear Information System (INIS)
Kilbas, Anatoly A; Pierantozzi, Teresa; Trujillo, Juan J; Vazquez, Luis
2004-01-01
This paper is devoted to the solution of the bi-fractional differential equation ( C D α t u)(t, x) = λ( L D β x u)(t, x) (t>0, -∞ 0 and λ ≠ 0, with the initial conditions lim x→±∞ u(t,x) = 0 u(0+,x)=g(x). Here ( C D α t u)(t, x) is the partial derivative coinciding with the Caputo fractional derivative for 0 L D β x u)(t, x)) is the Liouville partial fractional derivative ( L D β t u)(t, x)) of order β > 0. The Laplace and Fourier transforms are applied to solve the above problem in closed form. The fundamental solution of these problems is established and its moments are calculated. The special case α = 1/2 and β = 1 is presented, and its application is given to obtain the Dirac-type decomposition for the ordinary diffusion equation
Comparative study of void fraction models
International Nuclear Information System (INIS)
Borges, R.C.; Freitas, R.L.
1985-01-01
Some models for the calculation of void fraction in water in sub-cooled boiling and saturated vertical upward flow with forced convection have been selected and compared with experimental results in the pressure range of 1 to 150 bar. In order to know the void fraction axial distribution it is necessary to determine the net generation of vapour and the fluid temperature distribution in the slightly sub-cooled boiling region. It was verified that the net generation of vapour was well represented by the Saha-Zuber model. The selected models for the void fraction calculation present adequate results but with a tendency to super-estimate the experimental results, in particular the homogeneous models. The drift flux model is recommended, followed by the Armand and Smith models. (F.E.) [pt
Universal signatures of fractionalized quantum critical points.
Isakov, Sergei V; Melko, Roger G; Hastings, Matthew B
2012-01-13
Ground states of certain materials can support exotic excitations with a charge equal to a fraction of the fundamental electron charge. The condensation of these fractionalized particles has been predicted to drive unusual quantum phase transitions. Through numerical and theoretical analysis of a physical model of interacting lattice bosons, we establish the existence of such an exotic critical point, called XY*. We measure a highly nonclassical critical exponent η = 1.493 and construct a universal scaling function of winding number distributions that directly demonstrates the distinct topological sectors of an emergent Z(2) gauge field. The universal quantities used to establish this exotic transition can be used to detect other fractionalized quantum critical points in future model and material systems.
Chromium isotope fractionation in ferruginous sediments
Bauer, Kohen W.; Gueguen, Bleuenn; Cole, Devon B.; Francois, Roger; Kallmeyer, Jens; Planavsky, Noah; Crowe, Sean A.
2018-02-01
Ferrous Fe is a potent reductant of Cr(VI), and while a number of laboratory studies have characterized Cr isotope fractionation associated with Cr(VI) reduction by ferrous iron, the expression of this fractionation in real-world ferrous Fe-rich environments remains unconstrained. Here we determine the isotope fractionation associated with Cr(VI) reduction in modern ferrous Fe-rich sediments obtained from the previously well studied Lake Matano, Indonesia. Whole core incubations demonstrate that reduction of Cr(VI) within ferruginous sediments provides a sink for Cr(VI) leading to Cr(VI) concentration gradients and diffusive Cr(VI) fluxes across the sediment water interface. As reduction proceeded, Cr(VI) remaining in the overlying lake water became progressively enriched in the heavy isotope (53Cr), increasing δ53Cr by 2.0 ± 0.1‰ at the end of the incubation. Rayleigh distillation modelling of the evolution of Cr isotope ratios and Cr(VI) concentrations in the overlying water yields an effective isotope fractionation of εeff = 1.1 ± 0.2‰ (53Cr/52Cr), whereas more detailed diagenetic modelling implies an intrinsic isotope fractionation of εint = 1.80 ± 0.04‰. Parallel slurry experiments performed using anoxic ferruginous sediment yield an intrinsic isotope fractionation of εint = 2.2 ± 0.1‰. These modelled isotope fractionations are corroborated by direct measurement of the δ53Cr composition on the upper 0.5 cm of Lake Matano sediment, revealing an isotopic offset from the lake water of Δ53Cr = 0.21-1.81‰. The data and models reveal that effective isotope fractionations depend on the depth at which Cr(VI) reduction takes place below the sediment water interface-the deeper the oxic non-reactive zone, the smaller the effective fractionation relative to the intrinsic fractionation. Based on the geochemistry of the sediment we suggest the electron donors responsible for reduction are a combination of dissolved Fe(II) and 0.5 M HCl extractable (solid
Complete way to fractionalize Fourier transform
Yeung, Daniel S.; Ran, Qiwen; Tsang, Eric C. C.; Teo, Kok Lay
2004-01-01
We propose a complete way to fractionalize Fourier transform. This fractionalization can perfectly extend the fractional Fourier transform (FRFT) defined in [C.C. Shih, Opt. Commun. 118 (1995) 495] to the original one in [V. Namias, J. Inst. Math. Appl. 25 (1980) 241]. The new FRFT proposed in this paper can have any integer M(⩾3)-periodic eigenvalues not only with respect to the order of Hermite-Gaussian functions but also to the order of the transform, and it will be reduced to the FRFT in [Namias, loc. cit.; Shih, loc. cit.; S. Liu, J. Jiang, Y. Zhang, J. Zhang, J. Phys. A: Math. Gen. 30 (1997) 973] at the three limits with M=+∞, M=4, M=4 k ( k is a natural number), respectively.
Ethylene copolymers analysis by fractionation techniques
International Nuclear Information System (INIS)
Escher, Fernanda F.N.; Silva, Luciana P.; Galland, Griselda B.
2000-01-01
Samples of ethylene 1-butene copolymer,produced in laboratory by different processes using Ziegler-Natta catalysts, ethylene-1-hexene and metallocenes catalysts were fractionated according to molecular size by direct extraction by different solvents and at different temperatures. These samples were also fractionated by differences on crystallinity using a DSC calorimeter. The obtained fractions were characterized by 13 C-NMR, FTIR, GPC and DSC. The polyethylene copolymers produced by Ziegler-Natta catalyst were found more heterogeneous when compared with the one produced by metallocenes catalysts. The commercial resin produced by UCC process with Ziegler-Natta catalysts showed a more homogeneous incorporation of comonomer compared with the one obtained by the Spherilene process. The supported metallocenes catalyst gave a more homogeneous product than the homogeneous metallocene one. (author)
Theory of fractional quantum hall effect
International Nuclear Information System (INIS)
Kostadinov, I.Z.
1985-08-01
A theory of the Fractional Quantum Hall Effect is constructed based on magnetic flux fractionization, which lead to instability of the system against selfcompression. A theorem is proved stating that arbitrary potentials fail to lift a specific degeneracy of the Landau level. For the case of 1/3 fractional filling a model 3-particles interaction is constructed breaking the symmetry. The rigid 3-particles wave function plays the role of order parameter. In a BCS type of theory the gap in the single particles spectrum is produced by the 3-particles interaction. The mean field critical behaviour and critical parameters are determined as well as the Ginsburg-Landau equation coefficients. The Hall conductivity is calculated from the first principles and its temperature dependence is found. The simultaneous tunnelling of 3,5,7 etc. electrons and quantum interference effects are predicted. (author)
Isotope Fractionation in the Interstellar Medium
Charnley, Steven
2011-01-01
Anomalously fractionated isotopic material is found in many primitive Solar System objects, such as meteorites and comets. It is thought, in some cases, to trace interstellar matter that was incorporated into the Solar Nebula without undergoing significant processing. We will present the results of models of the nitrogen, oxygen, and carbon fractionation chemistry in dense molecular clouds, particularly in cores where substantial freeze-out of molecules on to dust has occurred. The range of fractionation ratios expected in different interstellar molecules will be discussed and compared to the ratios measured in molecular clouds, comets and meteoritic material. These models make several predictions that can be tested in the near future by molecular line observations, particularly with ALMA.
Deuterium Fractionation just after the Star Formation
Shibata, D.; Sakai, N.; Yamamoto, S.
2013-10-01
We have recently conducted a five-point strip observation of the DCO+, H13CO+, DNC, HN13C, and N2H+ lines toward low mass Class I protostar L1551 IRS5, and have evaluated the deuterium fractionation ratios DCO+/HCO+ and DNC/HNC. The DCO+/HCO+ ratio is found to be lower toward the protostar position than those toward the adjacent positions. On the other hand, the DNC/HNC ratio does not show such a decrease toward the protostar position. This suggests that the deuterium fractionation ratio of the neutral species is conserved after the star formation. If so, the deuterium fractionation of the neutral species can be used as a novel tracer to investigate the initial condition of the star formation process.
Fractional partial differential equations with boundary conditions
Baeumer, Boris; Kovács, Mihály; Sankaranarayanan, Harish
2018-01-01
We identify the stochastic processes associated with one-sided fractional partial differential equations on a bounded domain with various boundary conditions. This is essential for modelling using spatial fractional derivatives. We show well-posedness of the associated Cauchy problems in C0 (Ω) and L1 (Ω). In order to do so we develop a new method of embedding finite state Markov processes into Feller processes on bounded domains and then show convergence of the respective Feller processes. This also gives a numerical approximation of the solution. The proof of well-posedness closes a gap in many numerical algorithm articles approximating solutions to fractional differential equations that use the Lax-Richtmyer Equivalence Theorem to prove convergence without checking well-posedness.
Fractional-order RC and RL circuits
Radwan, Ahmed Gomaa
2012-05-30
This paper is a step forward to generalize the fundamentals of the conventional RC and RL circuits in fractional-order sense. The effect of fractional orders is the key factor for extra freedom, more flexibility, and novelty. The conditions for RC and RL circuits to act as pure imaginary impedances are derived, which are unrealizable in the conventional case. In addition, the sensitivity analyses of the magnitude and phase response with respect to all parameters showing the locations of these critical values are discussed. A qualitative revision for the fractional RC and RL circuits in the frequency domain is provided. Numerical and PSpice simulations are included to validate this study. © Springer Science+Business Media, LLC 2012.
Improving fish survival through turbines
International Nuclear Information System (INIS)
Ferguson, J.W.
1993-01-01
Much of what is known about fish passage through hydroturbines has been developed by studying migratory species of fish passing through large Kaplan turbine units. A review of the literature on previous fish passage research presented in the accompanying story illustrates that studies have focused on determining mortality levels, rather than identifying the causal mechanism involved. There is a need for understanding how turbine designs could be altered to improve fish passage conditions, how to retrofit existing units, and how proposed hydro plant operational changes may affect fish survival. The US Army Corps of Engineers has developed a research program to define biologically based engineering criteria for improving fish passage conditions. Turbine designs incorporating these criteria can be evaluated for their effects on fish survival, engineering issues, costs, and power production. The research program has the following objectives: To gain a thorough knowledge of the mechanisms of fish mortality; To define the biological sensitivities of key fish species to these mechanisms of mortality; To develop new turbine design criteria to reduce fish mortality; To construct prototype turbine designs, and to test these designs for fish passage, hydro-mechanical operation, and power production; and To identify construction and power costs associated with new turbine designs
Survival strategies in arctic ungulates
Directory of Open Access Journals (Sweden)
N. J. C. Tyler
1990-09-01
Full Text Available Arctic ungulates usually neither freeze nor starve to death despite the rigours of winter. Physiological adaptations enable them to survive and reproduce despite long periods of intense cold and potential undernutrition. Heat conservation is achieved by excellent insulation combined with nasal heat exchange. Seasonal variation in fasting metabolic rate has been reported in several temperate and sub-arctic species of ungulates and seems to occur in muskoxen. Surprisingly, there is no evidence for this in reindeer. Both reindeer and caribou normally maintain low levels of locomotor activity in winter. Light foot loads are important for reducing energy expenditure while walking over snow. The significance and control of selective cooling of the brain during hard exercise (e.g. escape from predators is discussed. Like other cervids, reindeer and caribou display a pronounced seasonal cycle of appetite and growth which seems to have an intrinsic basis. This has two consequences. First, the animals evidently survive perfectly well despite enduring negative energy balance for long periods. Second, loss of weight in winter is not necessarily evidence of undernutrition. The main role of fat reserves, especially in males, may be to enhance reproductive success. The principal role of fat reserves in winter appears to be to provide a supplement to, rather than a substitute for, poor quality winter forage. Fat also provides an insurance against death during periods of acute starvation.
Keller, Harald; Hope, Andrew; Meier, Gabriel; Davison, Matt
2013-08-01
To explore the potential of a novel dose-volume based metric to assist in the selection of optimal fractionation schedules for lung cancer patients. Selecting the dose per fraction that maximizes the therapeutic ratio via a linear-quadratic effect on normal tissue complication probability and tumor cell survival is an optimization problem. The mathematical solution reveals that the optimal fractionation schedule is determined by a generalized dose ratio between the normal tissue and the tumor, here termed the bifurcation number B, that can be derived from the dose-volume histogram of the normal tissue. The bifurcation number characterizes the volume effect of a normal tissue and its dependency on the fractionation schedule. The clinical relevance of the bifurcation number was evaluated in 46 patients previously treated for nonsmall cell lung cancer (NSCLC) according to various fractionation protocols. Bifurcation numbers were computed for both lung and esophagus as the normal tissues. The value of the bifurcation number determines whether the volume effect reverses the traditional radiobiological advantage of small dose per fraction for the normal tissue. If B is smaller than the ratio of alpha/beta ratios between normal tissue and tumor, then a single fraction is optimal; otherwise the optimal treatment is an infinite number of doses (hence the name "bifurcation" number). These fractionation schedules correspond clinically to hypo- and standard/hyperfractionation, respectively. Compared with traditional dose-volume metrics, the bifurcation number is a unitless ratio and independent of dose fractionation. The B-numbers derived from the clinical treatment plans are also strongly consistent with historically prescribed clinical fractionation protocols for NSCLC treatments. The B-numbers for esophagus and lung for all patients receiving a high dose per fraction protocol (>7.5 Gy/fraction) were all smaller than the B-numbers for the patients receiving standard 2 Gy/fraction
International Nuclear Information System (INIS)
Fertil, B.; Deschavanne, P.; Malaise, E.P.; Lachet, B.
1978-01-01
The 'in vitro' radiosensitivity to γ rays of 6 human cell lines is studied by the colony method: 3 cell lines are derived from colorectal carcinomas, one from a squamous cell carcinoma, one from a Melanoma and the last one is a non-transformed fibroblast cell line. We have attempted to get the lowest percentage of surviving cells as possible. We have used four statistical models to fit the different survival curves: the multitarget single hit, the multitarget two hits, the 'Wideroe', and the quadratic models. The main conclusions drawn from these analyses are the following: -the discrimination between the models could be done by the shape of the curve and the accuracy of the experimental results, but also by the determination of the cell survival after high doses. The quadratic model fits in best with the suvival curves of the 6 cell lines. It allows an accurate description of the shoulder of the survival curves and thus provides information for the comprehension of results in the radiotherapy of human cancers. The quadratic dependence of the surviving fraction on the dose is precisely determined; -significative differences in radiosensitivity show up among the cell lines. The biological interpretation of this finding is discussed: -concerning the fibroblast cell line, it appears that: as opposed to most results published till now, the interpretation of their survival curves must be based upon a quadratic radiation action. Despite their radiosensitivity higher than most other mammalian cells in vitro, fibroblast cells seem to have a comparable survival curve
Survival, growth and sexual maturation in Atlantic salmon exposed to infectious pancreatic necrosis
DEFF Research Database (Denmark)
Lillehammer, Marie; Ødegård, Jørgen; Madsen, Per
2013-01-01
Background Outbreaks of infectious pancreatic necrosis (IPN) in Atlantic salmon can result in reduced growth rates in a fraction of the surviving fish (runts). Genetic and environmental variation also affects growth rates within different categories of healthy animals and runts, which complicates...... may be useful for the genetic analysis of diseases detected mainly through indicator traits....... identification of runts. Mixture models are commonly used to identify the underlying structures in such data, and the aim of this study was to develop Bayesian mixture models for the genetic analysis of health status (runt/healthy) of surviving fish from an IPN outbreak. Methods Five statistical models were...
Measurement of void fractions by nuclear techniques
International Nuclear Information System (INIS)
Hernandez G, A.; Vazquez G, J.; Diaz H, C.; Salinas R, G.A.
1997-01-01
In this work it is done a general analysis of those techniques used to determine void fractions and it is chosen a nuclear technique to be used in the heat transfer circuit of the Physics Department of the Basic Sciences Management. The used methods for the determination of void fractions are: radioactive absorption, acoustic techniques, average velocity measurement, electromagnetic flow measurement, optical methods, oscillating absorption, nuclear magnetic resonance, relation between pressure and flow oscillation, infrared absorption methods, sound neutron analysis. For the case of this work it will be treated about the radioactive absorption method which is based in the gamma rays absorption. (Author)
Laser systems for ablative fractional resurfacing
DEFF Research Database (Denmark)
Paasch, Uwe; Haedersdal, Merete
2011-01-01
Ablative fractional resurfacing (AFR) creates microscopic vertical ablated channels that are surrounded by a thin layer of coagulated tissue, constituting the microscopic treatment zones (MTZs). AFR induces epidermal and dermal remodeling, which raises new possibilities for the treatment...... of a variety of skin conditions, primarily chronically photodamaged skin, but also acne and burn scars. In addition, it is anticipated that AFR can be utilized in the laser-assisted delivery of topical drugs. Clinical efficacy coupled with minimal downtime has driven the development of various fractional...
Numerical study of fractional nonlinear Schrodinger equations
Klein, Christian
2014-10-08
Using a Fourier spectral method, we provide a detailed numerical investigation of dispersive Schrödinger-type equations involving a fractional Laplacian in an one-dimensional case. By an appropriate choice of the dispersive exponent, both mass and energy sub- and supercritical regimes can be identified. This allows us to study the possibility of finite time blow-up versus global existence, the nature of the blow-up, the stability and instability of nonlinear ground states and the long-time dynamics of solutions. The latter is also studied in a semiclassical setting. Moreover, we numerically construct ground state solutions of the fractional nonlinear Schrödinger equation.
Conformable fractional Dirac system on time scales
Directory of Open Access Journals (Sweden)
Tuba Gulsen
2017-07-01
Full Text Available Abstract We study the conformable fractional (CF Dirac system with separated boundary conditions on an arbitrary time scale T $\\mathbb{T}$ . Then we extend some basic spectral properties of the classical Dirac system to the CF case. Eventually, some asymptotic estimates for the eigenfunction of the CF Dirac eigenvalue problem are obtained on T $\\mathbb{T} $ . So, we provide a constructive procedure for the solution of this problem. These results are important steps to consolidate the link between fractional calculus and time scale calculus in spectral theory.
Likelihood based testing for no fractional cointegration
DEFF Research Database (Denmark)
Lasak, Katarzyna
. The standard cointegration analysis only considers the assumption that deviations from equilibrium can be integrated of order zero, which is very restrictive in many cases and may imply an important loss of power in the fractional case. We consider the alternative hypotheses with equilibrium deviations...... that can be mean reverting with order of integration possibly greater than zero. Moreover, the degree of fractional cointegration is not assumed to be known, and the asymptotic null distribution of both tests is found when considering an interval of possible values. The power of the proposed tests under...
Fractional quantization and the quantum hall effect
International Nuclear Information System (INIS)
Guerrero, J.; Calixto, M.; Aldaya, V.
1998-01-01
Quantization with constrains is considered in a group-theoretical framework, providing a precise characterization of the set of good operators, i.e., those preserving the constrained Hilbert space, in terms of the representation of the subgroup of constraints. This machinery is applied to the quantization of the torus as symplectic manifold, obtaining that fractional quantum numbers are permitted, provided that we allow for vector valued representations. The good operators turn out to be the Wilson loops and, for certain representations of the subgroup of constraints, the modular transformations. These results are applied to the Fractional Quantum Hall Effect, where interesting implications are derived
Boron Isotope Fractionation in Bell Pepper
Geilert, Sonja; Vogl, Jochen; Rosner, Martin; Voerkelius, Susanne; Eichert, Thomas
2015-01-01
Various plant compartments of a single bell pepper plant were studied to verify the variability of boron isotope composition in plants and to identify possible intra-plant isotope fractionation. Boron mass fractions varied from 9.8 mg/kg in the fruits to 70.0 mg/kg in the leaves. Boron (B) isotope ratios reported as δ11B ranged from -11.0‰ to +16.0‰ (U ≤ 1.9‰, k=2) and showed a distinct trend to heavier δ11B values the higher the plant compartments were located in the plant. A fractionatio...
Hyperchaotic Chameleon: Fractional Order FPGA Implementation
Directory of Open Access Journals (Sweden)
Karthikeyan Rajagopal
2017-01-01
Full Text Available There are many recent investigations on chaotic hidden attractors although hyperchaotic hidden attractor systems and their relationships have been less investigated. In this paper, we introduce a hyperchaotic system which can change between hidden attractor and self-excited attractor depending on the values of parameters. Dynamic properties of these systems are investigated. Fractional order models of these systems are derived and their bifurcation with fractional orders is discussed. Field programmable gate array (FPGA implementations of the systems with their power and resource utilization are presented.
Laser systems for ablative fractional resurfacing
DEFF Research Database (Denmark)
Paasch, Uwe; Haedersdal, Merete
2011-01-01
ablative laser systems. Fractionated CO(2) (10,600-nm), erbium yttrium aluminum garnet, 2940-nm and yttrium scandium gallium garnet, 2790-nm lasers are available. In this article, we present an overview of AFR technology, devices and histopathology, and we summarize the current clinical possibilities...... of a variety of skin conditions, primarily chronically photodamaged skin, but also acne and burn scars. In addition, it is anticipated that AFR can be utilized in the laser-assisted delivery of topical drugs. Clinical efficacy coupled with minimal downtime has driven the development of various fractional...
Directory of Open Access Journals (Sweden)
A. Guezane-Lakoud
2012-01-01
Full Text Available This work is devoted to the existence of positive solutions for a fractional boundary value problem with fractional integral deviating argument. The proofs of the main results are based on Guo-Krasnoselskii fixed point theorem and Avery and Peterson fixed point theorem. Two examples are given to illustrate the obtained results, ending the paper.
Boeriu, C.G.; Fitigau, F.; Gosselink, R.J.A.; Frissen, A.E.; Stoutjesdijk, J.H.; Peter, F.
2014-01-01
Lignins from softwood, hardwood, grass and wheat straw were fractionated by selective extraction at ambient temperature using green solvents like acetone/water solutions of 10, 30, 50, 70 and 90% (v/v) acetone and ethyl acetate. A comparison between the isolated fractions and unfractionated lignins
Energy Technology Data Exchange (ETDEWEB)
Al-Wassia, Rolina; Dal Pra, Alan; Shun, Kitty; Shaban, Ahmed [Department of Oncology, Division of Radiation Oncology, Montreal General Hospital, McGill University Health Centre, Montreal, Quebec (Canada); Corriveau, Christine [Department of Ophthalmology, Notre Dame Hospital, Centre Hospitalier de l' Universite de Montreal, Montreal, Quebec (Canada); Edelstein, Chaim; Deschenes, Jean [Department of Ophthalmology, McGill University Health Centre, Montreal, Quebec (Canada); Ruo, Russel; Patrocinio, Horacio [Department of Medical Physics, Montreal General Hospital, McGill University Health Centre, Montreal, Quebec (Canada); Cury, Fabio L.B. [Department of Oncology, Division of Radiation Oncology, Montreal General Hospital, McGill University Health Centre, Montreal, Quebec (Canada); DeBlois, Francois [Department of Medical Physics, Jewish General Hospital, McGill University, Montreal, Quebec (Canada); Shenouda, George, E-mail: george.shenouda@muhc.mcgill.ca [Department of Oncology, Division of Radiation Oncology, Montreal General Hospital, McGill University Health Centre, Montreal, Quebec (Canada)
2011-11-15
Purpose: To report our experience with linear accelerator-based stereotactic fractionated radiotherapy in the treatment of juxtapapillary choroidal melanoma. Methods and Materials: We performed a retrospective review of 50 consecutive patients diagnosed with juxtapapillary choroidal melanoma and treated with linear accelerator-based stereotactic fractionated radiotherapy between April 2003 and December 2009. Patients with small to medium sized lesions (Collaborative Ocular Melanoma Study classification) located within 2 mm of the optic disc were included. The prescribed radiation dose was 60 Gy in 10 fractions. The primary endpoints included local control, enucleation-free survival, and complication rates. Results: The median follow-up was 29 months (range, 1-77 months). There were 31 males and 29 females, with a median age of 69 years (range, 30-92 years). Eighty-four percent of the patients had medium sized lesions, and 16% of patients had small sized lesions. There were four cases of local progression (8%) and three enucleations (6%). Actuarial local control rates at 2 and 5 years were 93% and 86%, respectively. Actuarial enucleation-free survival rates at 2 and 5 years were 94% and 84%, respectively. Actuarial complication rates at 2 and 5 years were 33% and 88%, respectively, for radiation-induced retinopathy; 9.3% and 46.9%, respectively, for dry eye; 12% and 53%, respectively, for cataract; 30% and 90%, respectively, for visual loss [Snellen acuity (decimal equivalent), <0.1]; 11% and 54%, respectively, for optic neuropathy; and 18% and 38%, respectively, for neovascular glaucoma. Conclusions: Linear accelerator-based stereotactic fractionated radiotherapy using 60 Gy in 10 fractions is safe and has an acceptable toxicity profile. It has been shown to be an effective noninvasive treatment for juxtapapillary choroidal melanomas.
Arshad, Muhammad; Lu, Dianchen; Wang, Jun
2017-07-01
In this paper, we pursue the general form of the fractional reduced differential transform method (DTM) to (N+1)-dimensional case, so that fractional order partial differential equations (PDEs) can be resolved effectively. The most distinct aspect of this method is that no prescribed assumptions are required, and the huge computational exertion is reduced and round-off errors are also evaded. We utilize the proposed scheme on some initial value problems and approximate numerical solutions of linear and nonlinear time fractional PDEs are obtained, which shows that the method is highly accurate and simple to apply. The proposed technique is thus an influential technique for solving the fractional PDEs and fractional order problems occurring in the field of engineering, physics etc. Numerical results are obtained for verification and demonstration purpose by using Mathematica software.
International Nuclear Information System (INIS)
Eab, C. H.; Lim, S. C.; Teo, L. P.
2007-01-01
This paper studies the Casimir effect due to fractional massless Klein-Gordon field confined to parallel plates. A new kind of boundary condition called fractional Neumann condition which involves vanishing fractional derivatives of the field is introduced. The fractional Neumann condition allows the interpolation of Dirichlet and Neumann conditions imposed on the two plates. There exists a transition value in the difference between the orders of the fractional Neumann conditions for which the Casimir force changes from attractive to repulsive. Low and high temperature limits of Casimir energy and pressure are obtained. For sufficiently high temperature, these quantities are dominated by terms independent of the boundary conditions. Finally, validity of the temperature inversion symmetry for various boundary conditions is discussed
Bildstein, Steve
2018-02-01
In this paper, we review the fractional derivative and apply it to various problems in quantum mechanics. Among other things, we find fractional angular momentum, with "fractional spherical harmonics" as solutions to the squared quantum mechanical angular momentum operator, but with non-integer eigenvalues. These fractional functions might be interpreted as intermediary states visited by an orbiting electron as it jumps between the more stable, integer angular momentum values in an atom. Alternatively, these fractional states may be of interest in the mechanisms of chemical bonding. The justification for these new states, which are normalizable solutions to Hermitian operators, depends of course on experiment. We remember Feynmann's statement about quantum mechanics, "Everything that is not expressly forbidden, is mandatory."
Development of a multi-fraction radiation protocol for intracerebral human glioblastoma xenografts
International Nuclear Information System (INIS)
Ozawa, T.; Santos, R.A.; Hu, L.H.; Faddegon, B.A.; Lamborn, K.R.; Deen, D.F.
2003-01-01
Patients with malignant gliomas are typically treated by surgery, radiation therapy and chemotherapy. Fractionated radiotherapy consists of 30 daily doses of 1.8 to 2 Gy given over a 6-week period. We have investigated a multi-fraction radiation protocol in which rats bearing intracerebral tumors are irradiated once daily for 10 days with a 2-day break in the middle. This scheme simulates the first third of a typical human radiation protocol, and it is a practical scheme to conduct in the laboratory. U-87 MG or U-251 MG human glioblastoma cells were implanted into the right caudate-putamens of male athymic rats. We irradiated rats using an irradiation jig that allowed us to deliver Cesium-137 photons at a dose rate of 280 cGy/minute selectively to the portion of the head containing the tumor. This device adequately shields all other parts of rat, including the critically sensitive oropharynx. Animals received the first radiation dose when intracerebral tumors were ∼20 mg in size. Untreated U-87 MG tumor-bearing rats died with a median survival of 23 days, while tumor bearing rats that were given ten 1-Gy doses died with a median survival of 28.5 days. Untreated U-251 MG tumor-bearing rats died with a median survival of 34.5 days, while tumor-bearing rats that were given ten 1-Gy doses died with a median survival of 58 days. However, 5 of 14 of these rats had a lifespan >68 days and were considered cured. A daily dose of 0.75 Gy produced a median survival of 43 days, but again 2 rats had a lifespan >70 days. Currently, we are seeking a dose that causes reproducible tumor growth delay of 1 to 2 weeks, without curing any animals, to use in future studies that combine radiation with other anti-tumor agents
Probability dynamics of a repopulating tumor in case of fractionated external radiotherapy.
Stavreva, Nadia; Stavrev, Pavel; Fallone, B Gino
2009-12-01
In this work two analytical methods are developed for computing the probability distribution of the number of surviving cells of a repopulating tumor during a fractionated external radio-treatment. Both methods are developed for the case of pure birth processes. They both allow the description of the tumor dynamics in case of cell radiosensitivity changing in time and for treatment schedules with variable dose per fraction and variable time intervals between fractions. The first method is based on a direct solution of the set of differential equations describing the tumor dynamics. The second method is based on the works of Hanin et al. [Hanin LG, Zaider M, Yakovlev AY. Distribution of the number of clonogens surviving fractionated radiotherapy: a long-standing problem revisited. Int J Radiat Biol 2001;77:205-13; Hanin LG. Iterated birth and death process as a model of radiation cell survival. Math Biosci 2001;169:89-107; Hanin LG. A stochastic model of tumor response to fractionated radiation: limit theorems and rate of convergence. Math Biosci 2004;191:1-17], where probability generating functions are used. In addition a Monte Carlo algorithm for simulating the probability distributions is developed for the same treatment conditions as for the analytical methods. The probability distributions predicted by the three methods are compared graphically for a certain set of values of the model parameters and an excellent agreement is found to exist between all three results, thus proving the correct implementation of the methods. However, numerical difficulties have been encountered with both analytical methods depending on the values of the model parameters. Therefore, the Poisson approximation is also studied and it is compared to the exact methods for several different combinations of the model parameter values. It is concluded that the Poisson approximation works sufficiently well only for slowly repopulating tumors and a low cell survival probability and that it
Surviving Scientific Academia . . . and Beyond
Energy Technology Data Exchange (ETDEWEB)
Conlin, Jeremy Lloyd [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-02-03
It's been 16 years since I first took a physics class at Weber State University. Since them, I've survived graduate school in Nuclear Engineering, and a postdoc appointment doing nuclear nonproliferation. Now I'm a Technical Staff Member at Los Alamos National Laboratory working with nuclear data, the physics behind the numerical simulations of nuclear reactors and nuclear weapons. Along the way, I've learned a few things. First, scientific computing is everywhere in science. If you are not writing codes, you will be analyzing their output, and generally there will be more output than a human can correctly and accurately interpret in a timely manner. Second, a career in science or engineering can be very rewarding with opportunities to collaborate with and generate friendships with very bright people from all over the world.
Additive interaction in survival analysis
DEFF Research Database (Denmark)
Rod, Naja Hulvej; Lange, Theis; Andersen, Ingelise
2012-01-01
It is a widely held belief in public health and clinical decision-making that interventions or preventive strategies should be aimed at patients or population subgroups where most cases could potentially be prevented. To identify such subgroups, deviation from additivity of absolute effects...... of additive interaction derived from multiplicative models-an approach that is both counter-intuitive and sometimes invalid. This paper presents a straightforward and intuitive way of assessing deviation from additivity of effects in survival analysis by use of the additive hazards model. The model directly...... an empirical example of interaction between education and smoking on risk of lung cancer. We argue that deviations from additivity of effects are important for public health interventions and clinical decision-making, and such estimations should be encouraged in prospective studies on health. A detailed...
Development of an ultrasonic void fraction profiler
International Nuclear Information System (INIS)
Murai, Yuichi; Ohta, Shoko; Shigetomi, Akinari; Tasaka, Yuji; Takeda, Yasushi
2009-01-01
A method for measuring the spatial distribution of the void fraction in bubbly two-phase flow is presented. The method is referred to as ultrasonic void fraction profiling since it is based on the signal processing of an ultrasonic pulse scattering on a bubble interface. The method is established using two processes for the ultrasonic sensing of bubbles. One approach is to detect the bubble interface along a measurement line, i.e. the path of the ultrasonic pulse in the liquid. The interface is captured using two types of signal-processing schemes: the echo intensity method and the Doppler method. The other approach is to reconstruct the void fraction profile from the number of bubble interfaces. A theoretical formula for the estimation is proposed by considering ultrasonic reflection in a suspension of bubbles. The validity of the formula is examined with theoretical and numerical bases. Finally, the method developed here is applied to four flow configurations for the demonstration, in which the void fraction profile governs the modulation of liquid flow field
Introducing the fractional order robotic Darwinian PSO
Couceiro, Micael S.; Martins, Fernando M. L.; Rocha, Rui P.; Ferreira, Nuno M. F.
2012-11-01
The Darwinian Particle Swarm Optimization (DPSO) is an evolutionary algorithm that extends the Particle Swarm Optimization using natural selection to enhance the ability to escape from sub-optimal solutions. An extension of the DPSO to multi-robot applications has been recently proposed and denoted as Robotic Darwinian PSO (RDPSO), benefiting from the dynamical partitioning of the whole population of robots, hence decreasing the amount of required information exchange among robots. This paper further extends the previously proposed algorithm using fractional calculus concepts to control the convergence rate, while considering the robot dynamical characteristics. Moreover, to improve the convergence analysis of the RDPSO, an adjustment of the fractional coefficient based on mobile robot constraints is presented and experimentally assessed with 2 real platforms. Afterwards, this novel fractional-order RDPSO is evaluated in 12 physical robots being further explored using a larger population of 100 simulated mobile robots within a larger scenario. Experimental results show that changing the fractional coefficient does not significantly improve the final solution but presents a significant influence in the convergence time because of its inherent memory property.
FLUORESCENCE IN DISSOLVED FRACTIONS OF HUMAN ENAMEL
HAFSTROMBJORKMAN, U; SUNDSTROM, F; TENBOSCH, JJ
Fluorescence induced by laser light is useful in early detection of enamel caries. The present work studied the fluorescence emission pattern in dissolved human enamel and in different molecular weight fractions obtained after gel chromatography or dialysis followed by ultrafiltration. For
Intelligent fractions learning system: conceptual design
CSIR Research Space (South Africa)
Laine, TH
2010-01-01
Full Text Available UFractions is a ubiquitous learning environment which combines mobile technology, tangible fraction blocks and a story-based game into a mathematical learning experience. In this paper the authors present a novel concept for monitoring a user’s...
Ultraviolet spectroscopic evaluation of bioactive saponin fraction ...
African Journals Online (AJOL)
Ultraviolet spectroscopic evaluation of bioactive saponin fraction from the aqueous extract of Vernonia amygdalina [Esteraeceae] leaf. Paul Chukwuemeka ADIUKWU 1*, Martina BONSU 1, Inemesit OKON-BEN 1,. Paul PEPRAH 1, Paapa MENSAH-KANE 1, Jonathan JATO 1 and Grace NAMBATYA 2. 1School of Pharmacy ...
Methanol fractionations of Catha edulis frosk (Celastraceae ...
African Journals Online (AJOL)
The study investigated the effect of methanol extract and its fractionations obtained from Yemeni khat on the smooth muscle isometric tension in Lewis rat aortal ring preparations and compared the effects of the crimson and green leaves. Khat leaves were sorted into green (khat Light; KL) and crimson (khat Dark; KD) leaves ...
Quantitative metric theory of continued fractions
Indian Academy of Sciences (India)
2 (log log n). 1. 2 +ǫ) almost everywhere with respect to the Lebesgue measure. Keywords. Continued fractions; ergodic averages; metric theory of numbers. Mathematics Subject Classification. Primary: 11K50; Secondary: 28D99. 1. Introduction. In this paper, we use a quantitative L2-ergodic theorem to study the metrical ...
Inequalities forα-fractional differentiable functions.
Chu, Yu-Ming; Adil Khan, Muhammad; Ali, Tahir; Silvestru Dragomir, Sever
2017-01-01
In this article, we present an identity and several Hermite-Hadamard type inequalities for conformable fractional integrals. As applications, we establish some inequalities for certain special means of two positive real numbers and give the error estimations for the trapezoidal formula.
A computational model of fraction arithmetic.
Braithwaite, David W; Pyke, Aryn A; Siegler, Robert S
2017-10-01
Many children fail to master fraction arithmetic even after years of instruction, a failure that hinders their learning of more advanced mathematics as well as their occupational success. To test hypotheses about why children have so many difficulties in this area, we created a computational model of fraction arithmetic learning and presented it with the problems from a widely used textbook series. The simulation generated many phenomena of children's fraction arithmetic performance through a small number of common learning mechanisms operating on a biased input set. The biases were not unique to this textbook series-they were present in 2 other textbook series as well-nor were the phenomena unique to a particular sample of children-they were present in another sample as well. Among other phenomena, the model predicted the high difficulty of fraction division, variable strategy use by individual children and on individual problems, relative frequencies of different types of strategy errors on different types of problems, and variable effects of denominator equality on the four arithmetic operations. The model also generated nonintuitive predictions regarding the relative difficulties of several types of problems and the potential effectiveness of a novel instructional approach. Perhaps the most general lesson of the findings is that the statistical distribution of problems that learners encounter can influence mathematics learning in powerful and nonintuitive ways. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
Fractional superLie algebras and groups
Energy Technology Data Exchange (ETDEWEB)
Ahmedov, H. [Feza Gursey Institute, Cengelkoy, Istanbul (Turkey)]. E-mail: hagi@gursey.gov.tr; Yildiz, A. [ Feza Gursey Institute, Cengelkoy, Istanbul (Turkey); Ucan, Y. [Yildiz Technical University, Department of Mathematics, Besiktas, Istanbul (Turkey)
2001-08-24
The nth root of a Lie algebra and its dual (that is the fractional supergroup) based on the permutation group S{sub n} invariant forms is formulated in the Hopf algebra formalism. Detailed discussion of S{sub 3}-graded sl(2) algebras is performed. (author)
A new algorithm for generalized fractional programs
J.B.G. Frenk (Hans); A.I. Barros (Ana); S. Schaible; S. Zhang (Shuzhong)
1996-01-01
textabstractA new dual problem for convex generalized fractional programs with no duality gap is presented and it is shown how this dual problem can be efficiently solved using a parametric approach. The resulting algorithm can be seen as “dual” to the Dinkelbach-type algorithm for generalized
Multiparticle quantum mechanics obeying fractional statistics
International Nuclear Information System (INIS)
Wu, Y.
1984-01-01
We obtain the rule governing many-body wave functions for particles obeying fractional statistics in two (space) dimensions. It generalizes and continuously interpolates the usual symmetrization and antisymmetrization. Quantum mechanics of more than two particles is discussed and some new features are found
Goldstone bosons as fractional cosmic neutrinos.
Weinberg, Steven
2013-06-14
It is suggested that Goldstone bosons may be masquerading as fractional cosmic neutrinos, contributing about 0.39 to what is reported as the effective number of neutrino types in the era before recombination. The broken symmetry associated with these Goldstone bosons is further speculated to be the conservation of the particles of dark matter.
Fractional laser-assisted drug delivery
DEFF Research Database (Denmark)
Taudorf, Elisabeth Hjardem; Lerche, C.M.; Erlendsson, A M
2016-01-01
BACKGROUND AND OBJECTIVE: Ablative fractional laser (AFXL) facilitates delivery of topical methotrexate (MTX). This study investigates impact of laser-channel depth on topical MTX-delivery. MATERIALS AND METHODS: MTX (1% [w/v]) diffused for 21 hours through AFXL-exposed porcine skin in in vitro F...
Microdevice for separation and quantitative fraction collection
Czech Academy of Sciences Publication Activity Database
Spěšný, Michal; Foret, František
2003-01-01
Roč. 24, č. 21 (2003), s. 3745-3747 ISSN 0173-0835 R&D Projects: GA AV ČR IBS4031209 Institutional research plan: CEZ:AV0Z4031919 Keywords : microfluidic system * miniaturization * whole-column fraction collection Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.040, year: 2003
reaction-diffusion system with fractional derivatives
Directory of Open Access Journals (Sweden)
Kamel Haouam
2006-01-01
Full Text Available We give some necessary conditions for local and global existence of a solution to reaction-diffusion system of type (FDS with temporal and spacial fractional derivatives. As in the case of single equation of type (STFE studied by M. Kirane et al. (2005, we prove that these conditions depend on the behavior of initial conditions for large |x|.
(Asteraceae) Fraction against Human Cancer Cell Lines
African Journals Online (AJOL)
Purpose: To investigate the anti-proliferative and apoptotic activity of crude and dichloromethane fraction of A. sieberi against seven cancer cell lines (Colo20, HCT116, DLD, MCF7, Jurkat, HepG2 and L929). Methods: A. sieberi was extracted with methanol and further purification was carried out using liquidliquid extraction ...
Higher Order and Fractional Diffusive Equations
Directory of Open Access Journals (Sweden)
D. Assante
2015-07-01
Full Text Available We discuss the solution of various generalized forms of the Heat Equation, by means of different tools ranging from the use of Hermite-Kampé de Fériet polynomials of higher and fractional order to operational techniques. We show that these methods are useful to obtain either numerical or analytical solutions.
Developmental Predictors of Fraction Concepts and Procedures
Jordan, Nancy C.; Hansen, Nicole; Fuchs, Lynn S.; Siegler, Robert S.; Gersten, Russell; Micklos, Deborah
2013-01-01
Developmental predictors of children's fraction concepts and procedures at the end of fourth grade were investigated in a 2-year longitudinal study. Participants were 357 children who started the study in third grade. Attentive behavior, language, nonverbal reasoning, number line estimation, calculation fluency, and reading fluency each…
Void fraction instrument acceptance test procedure
International Nuclear Information System (INIS)
Pearce, K.L.
1994-01-01
This acceptance test procedure (ATP) was written to test the void fraction instrument (VFI) and verify that the unit is ready for field service. The procedure verifies that the mechanical and electrical features (not specifically addressed in the software ATP) and software alarms are operating as designed
Identities for generalized fractional integral operators associated ...
African Journals Online (AJOL)
In this present work an attempt has been made to define two generalized fractional integral operators associated with products of analogues to Dirichlet averages and special functions. Discussions on the different aspects of the obtained results have been followed by utilization in finding out the images of multivariate ...
Copper isotope fractionation by desert shrubs
International Nuclear Information System (INIS)
Navarrete, Jesica U.; Viveros, Marian; Ellzey, Joanne T.; Borrok, David M.
2011-01-01
Copper has two naturally occurring stable isotopes of masses 63 and 65 which can undergo mass dependent fractionation during various biotic and abiotic chemical reactions. These interactions and their resulting Cu isotope fractionations can be used to determine the mechanisms involved in the cycling of Cu in natural systems. In this study, Cu isotope changes were investigated at the organismal level in the metal-accumulating desert plant, Prosopis pubescens. Initial results suggest that the lighter Cu isotope was preferentially incorporated into the leaves of the plant, which may suggest that Cu was actively transported via intracellular proteins. The roots and stems show a smaller degree of Cu isotope fractionation and the direction and magnitude of the fractionations was dependent upon the levels of Cu exposure. Based on this and previous work with bacteria and yeast, a trend is emerging that suggests the lighter Cu isotope is preferentially incorporated into biological components, while the heavier Cu isotope tends to become enriched in aqueous solutions. In bacteria, plants and animals, intracellular Cu concentrations are strictly regulated via dozens of enzymes that can bind, transport, and store Cu. Many of these enzymes reduce Cu(II) to Cu(I). These initial results seem to fit into a broader picture of Cu isotope cycling in natural systems where oxidation/reduction reactions are fundamental in controlling the distributions of Cu isotopes.
Generalized Functions for the Fractional Calculus
Lorenzo, Carl F.; Hartley, Tom T.
1999-01-01
Previous papers have used two important functions for the solution of fractional order differential equations, the Mittag-Leffler functionE(sub q)[at(exp q)](1903a, 1903b, 1905), and the F-function F(sub q)[a,t] of Hartley & Lorenzo (1998). These functions provided direct solution and important understanding for the fundamental linear fractional order differential equation and for the related initial value problem (Hartley and Lorenzo, 1999). This paper examines related functions and their Laplace transforms. Presented for consideration are two generalized functions, the R-function and the G-function, useful in analysis and as a basis for computation in the fractional calculus. The R-function is unique in that it contains all of the derivatives and integrals of the F-function. The R-function also returns itself on qth order differ-integration. An example application of the R-function is provided. A further generalization of the R-function, called the G-function brings in the effects of repeated and partially repeated fractional poles.
Statistical properties of the seasonal fractionally integrated ...
African Journals Online (AJOL)
In this paper we introduce a new model called Fractionally Integrated Separable Spatial Autoregressive processes with Seasonality and denoted Seasonal FISSAR. We focus on the class of separable spatial models whose correlation structure can be expressed as a product of correlations. This new modelling allows taking ...
Fractional behaviour at cyclic stretch-bending
Emmens, W.C.; van den Boogaard, Antonius H.; Kazantzis, A.V.; de Hosson, J.Th.M.; Kolleck, R
2010-01-01
The fractional behaviour at cyclic stretch-bending has been studied by performing tensile tests at long specimens that are cyclically bent at the same time, on mild steel, dual-phase steel, stainless steel, aluminium and brass. Several types of fracture are observed, these are discussed, as are the
Integral and fractional quantum Hall Ising ferromagnets
Czech Academy of Sciences Publication Activity Database
Výborný, Karel; Čertík, Ondřej; Pfannkuche, D.; Wodzinski, D.; Wójs, A.; Quinn, J.J.
2007-01-01
Roč. 75, č. 4 (2007), 045434/1-045434/10 ISSN 1098-0121 R&D Projects: GA MŠk LC510 Institutional research plan: CEZ:AV0Z10100521 Keywords : quantum Hall ferromagnet * fractional quantum Hall effect ( FQHE) * Ising ferromagnet * exact diagonalization Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.172, year: 2007
Chaos in discrete fractional difference equations
Indian Academy of Sciences (India)
2016-09-07
Sep 7, 2016 ... tions in the mathematical modelling of real-world phenomena with memory effects. In the present paper, the chaotic behaviour of ... tives allow us to deal comfortably with memory effects in dynamical systems [2]. Discrete ..... House, Reading, Connecticut, USA, 2006). [6] F Mainardi, Fractional calculus and ...
Antioxidative potential of polysaccharide fractions produced from ...
African Journals Online (AJOL)
Cordyceps jiangxiensis, also called 'CaoMuWang', is a medicinal entomopathogenic macrofungus native to eastern China. Polysaccharide fractions from cultured C. jiangxiensis exhibited potent antitumor activity via the induction of cell cycle arrest and apoptotic pathway. Antioxidant pathway is also one action of ...
Antioxidative potential of polysaccharide fractions produced from ...
African Journals Online (AJOL)
Jane
2011-07-11
Jul 11, 2011 ... Cordyceps jiangxiensis, also called 'CaoMuWang', is a medicinal entomopathogenic macrofungus native to eastern China. Polysaccharide fractions from cultured C. jiangxiensis exhibited potent antitumor activity via the induction of cell cycle arrest and apoptotic pathway. Antioxidant pathway is also one ...
Modeling electron fractionalization with unconventional Fock spaces
Cobanera, Emilio
2017-08-01
It is shown that certain fractionally-charged quasiparticles can be modeled on D-dimensional lattices in terms of unconventional yet simple Fock algebras of creation and annihilation operators. These unconventional Fock algebras are derived from the usual fermionic algebra by taking roots (the square root, cubic root, etc) of the usual fermionic creation and annihilation operators. If the fermions carry non-Abelian charges, then this approach fractionalizes the Abelian charges only. In particular, the mth-root of a spinful fermion carries charge e/m and spin 1/2. Just like taking a root of a complex number, taking a root of a fermion yields a mildly non-unique result. As a consequence, there are several possible choices of quantum exchange statistics for fermion-root quasiparticles. These choices are tied to the dimensionality D=1,2,3,\\ldots of the lattice by basic physical considerations. One particular family of fermion-root quasiparticles is directly connected to the parafermion zero-energy modes expected to emerge in certain mesoscopic devices involving fractional quantum Hall states. Hence, as an application of potential mesoscopic interest, I investigate numerically the hybridization of Majorana and parafermion zero-energy edge modes caused by fractionalizing but charge-conserving tunneling.
Thyroid tumours following fractionated irradiation in childhood
International Nuclear Information System (INIS)
Vathaire, F. de; Grimaud, E.; Diallo, I.; Shamsaldin, A.
1997-01-01
Results of a cohort study designed to evaluate the long term risk of thyroid tumours after fractioned high doses of external beam radiotherapy received by the thyroid are reported. In this cohort study, doses have been estimated for each child. (author)
Significance of Assimilation and Fractional Crystallization (AFC ...
Indian Academy of Sciences (India)
57
andesites of the Chhotaudepur area plot close to a consistent mixing trend between typical mantle composition ... Deccan tholeiites and alkaline felsic rocks also exhibit a significant trend of crustal contamination. .... Keeping the rate of assimilation to fractional crystallization (r) as 0.3, the binary plotting was carried out and.
Simulation and optimization of fractional crystallization processes
DEFF Research Database (Denmark)
Thomsen, Kaj; Rasmussen, Peter; Gani, Rafiqul
1998-01-01
and optimization of fractional crystallization processes are shown. In one of these examples, a process with multiple steady states is analyzed. The thermodynamic model applied for describing the highly non-ideal aqueous electrolyte systems is the Extended UNIQUAC model. (C) 1998 Published by Elsevier Science Ltd....... All rights reserved....
Remarks for one-dimensional fractional equations
Directory of Open Access Journals (Sweden)
Massimiliano Ferrara
2014-01-01
Full Text Available In this paper we study a class of one-dimensional Dirichlet boundary value problems involving the Caputo fractional derivatives. The existence of infinitely many solutions for this equations is obtained by exploiting a recent abstract result. Concrete examples of applications are presented.
Deuterium fractionation in dense interstellar clouds
International Nuclear Information System (INIS)
Millar, T.J.; Bennett, A.; Herbst, E.
1989-01-01
The time-dependent gas-phase chemistry of deuterium fractionation in dense interstellar clouds ranging in temperature between 10 and 70 K was investigated using a pseudo-time-dependent model similar to that of Brown and Rice (1986). The present approach, however, considers much more complex species, uses more deuterium fractionation reactions, and includes the use of new branching ratios for dissociative recombinations reactions. Results indicate that, in cold clouds, the major and most global source of deuterium fractionation is H2D(+) and ions derived from it, such as DCO(+) and H2DO(+). In warmer clouds, reactions of CH2D(+), C2HD(+), and associated species lead to significant fractionation even at 70 K, which is the assumed Orion temperature. The deuterium abundance ratios calculated at 10 K are consistent with those observed in TMC-1 for most species. However, a comparison between theory and observatiom for Orion, indicates that, for species in the ambient molecular cloud, the early-time results obtained with the old dissociative recombination branching ratios are superior if a temperature of 70 K is utilized. 60 refs
Deuterium fractionation in dense interstellar clouds
Millar, T. J.; Bennett, A.; Herbst, Eric
1989-05-01
The time-dependent gas-phase chemistry of deuterium fractionation in dense interstellar clouds ranging in temperature between 10 and 70 K was investigated using a pseudo-time-dependent model similar to that of Brown and Rice (1986). The present approach, however, considers much more complex species, uses more deuterium fractionation reactions, and includes the use of new branching ratios for dissociative recombinations reactions. Results indicate that, in cold clouds, the major and most global source of deuterium fractionation is H2D(+) and ions derived from it, such as DCO(+) and H2DO(+). In warmer clouds, reactions of CH2D(+), C2HD(+), and associated species lead to significant fractionation even at 70 K, which is the assumed Orion temperature. The deuterium abundance ratios calculated at 10 K are consistent with those observed in TMC-1 for most species. However, a comparison between theory and observatiom for Orion, indicates that, for species in the ambient molecular cloud, the early-time results obtained with the old dissociative recombination branching ratios are superior if a temperature of 70 K is utilized.
Characterization of carbohydrate fractions and fermentation quality ...
African Journals Online (AJOL)
This experiment was carried out to evaluate the effects of adding fast-sile (FS), previous fermented juice (PFJ), sucrose (S) or fast-sile + sucrose (FS + S) on the fermentation characteristics and carbohydrates fractions of alfalfa silages by the Cornell net carbohydrates and proteins systems (CNCPS). Silages quality were well ...
Fingertip replantation: determinants of survival.
Li, Jing; Guo, Zheng; Zhu, Qingsheng; Lei, Wei; Han, Yisheng; Li, Mingquan; Wang, Zhen
2008-09-01
The purpose of this study was to determine the risk factors for an unsuccessful replanted fingertip. Two hundred eleven complete fingertip amputations in 211 patients who underwent replantation surgery between August of 1990 and March of 2006 were included in this study. The patients' age, gender, smoking history, digit position, dominant hand, amputation level, injury mechanism, platelet count, ischemia time, preservation method of the amputated part, anesthesia, number of arteries repaired, venous drainage, use of vein grafting, neurorrhaphy, bone shortening, and smoking after operation were tested for their impact on fingertip survival. One hundred seventy-two of 211 patients (81.5 percent) had a successful replantation. Univariate analysis showed crush or avulsion injury, high platelet count, and inappropriate preservation of the amputated part in saline solution or ethanol to be associated with a high incidence of replantation failure. Twenty-two of 54 patients (41 percent) who had a crush or avulsion trauma had failed replantation. Logistic regression analysis identified injury mechanism, platelet count, smoking after operation, preservation method of the amputated part, and the use of vein grafting as statistically significant predictive factors for success or failure. Injury mechanism, platelet count, smoking after operation, preservation method of amputated part, and the use of vein grafting were found to be the main predictors for the survival of the replanted fingertip. Applying external bleeding in zone 1 and venous drainage through the medullary cavity in zone 2 or venous anastomosis combined with vein grafting rather than venous anastomosis alone were strongly recommended in the fingertip replantation of crush or avulsion injury.
MRI survival guide; MRT Basiskurs
Energy Technology Data Exchange (ETDEWEB)
Cardoza, J. [Alta Imaging Medical Group and Magnetic Imaging Affiliates, Berkeley, CA (United States); Herfkens, R.J. [eds.] [Stanford Univ., CA (United States). Medical Center
1999-07-01
The book is a German translation of an American textbook with the original title ''MRI Survival Guide'' and is intended to serve as an introductory guide for beginners or a reference book for quick information. Readers will find information on the fundamentals of the technology and methodology of MRI as well as all details of relevance to practice in a precise and easy-to-grasp arrangement, covering all anatomic areas of interest, illustrations and descriptions of characteristic signs of pathologic processes, high-quality and unusually large-sized diagnostic pictures, a modern didactic concept for quick orientiation, including surveys, tables, and reproductions for visualisation of contents. (orig./CB) [German] Praktisch jeder Mediziner wird im Laufe seiner Berufstaetigkeit mit der MRT konfrontiert - unabhaengig davon ob in der Radiologie, Orthopaedie, Gynaekologie, Chirurgie, Neurologie oder sonstigen Fachrichtung. Das Buch ist eine Uebersetzung eines amerikanischen Lehrbuches mit dem Originaltitel ''MRI Survival Guide'' und will eine wesentliche Erleichterung als 'Ueberlebenshandbuch fuer die MRT' bieten: - Darstellung aller relevanten Grundlagen zu Technik, verschiedenen Sequenzen und Methodik der MRT - knapp und mit maximalem Praxisbezug - Beruecksichtigung aller moeglichen Untersuchungsregionen und strukturierte Orientierung daran (Gehirn, Wirbelsaeule, Kopf/Nacken, Brustkorb, Bauch, Becken, Muskel-Skelett-Bereich) - Illustration und Beschreibung der charakteristischen Erscheinungsmerkmale aller haeufigen pathologischen Prozesse im MRT, inklusive direkt umsetzbarer differentialdiagnostischer Abgrenzungskriterien - hochwertiges und aussergewoehnlich gross dimensioniertes Bildmaterial - modernes, didaktisches Konzept fuer die rasche Orientierung mit vielen Uebersichten, Tabellen und Abbildungen zur Visualisierung der Inhalte, Praxistips und Aufzeigen von Fehlermoeglichkeiten - zum Einstieg, zur Rekapitulation
Fractionated radiosurgery for painful spinal metastases: DOSIS - a phase II trial
Directory of Open Access Journals (Sweden)
Guckenberger Matthias
2012-11-01
Full Text Available Abstract Background One third of all cancer patients will develop bone metastases and the vertebral column is involved in approximately 70% of these patients. Conventional radiotherapy with of 1–10 fractions and total doses of 8-30 Gy is the current standard for painful vertebral metastases; however, the median pain response is short with 3–6 months and local tumor control is limited with these rather low irradiation doses. Recent advances in radiotherapy technology – intensity modulated radiotherapy for generation of highly conformal dose distributions and image-guidance for precise treatment delivery – have made dose-escalated radiosurgery of spinal metastases possible and early results of pain and local tumor control are promising. The current study will investigate efficacy and safety of radiosurgery for painful vertebral metastases and three characteristics will distinguish this study. 1 A prognostic score for overall survival will be used for selection of patients with longer life expectancy to allow for analysis of long-term efficacy and safety. 2 Fractionated radiosurgery will be performed with the number of treatment fractions adjusted to either good (10 fractions or intermediate (5 fractions life expectancy. Fractionation will allow inclusion of tumors immediately abutting the spinal cord due to higher biological effective doses at the tumor - spinal cord interface compared to single fraction treatment. 3 Dose intensification will be performed in the involved parts of the vertebrae only, while uninvolved parts are treated with conventional doses using the simultaneous integrated boost concept. Methods / Design It is the study hypothesis that hypo-fractionated image-guided radiosurgery significantly improves pain relief compared to historic data of conventionally fractionated radiotherapy. Primary endpoint is pain response 3 months after radiosurgery, which is defined as pain reduction of ≥ 2 points at the treated
Revised models of interstellar nitrogen isotopic fractionation
Wirström, E. S.; Charnley, S. B.
2018-03-01
Nitrogen-bearing molecules in cold molecular clouds exhibit a range of isotopic fractionation ratios and these molecules may be the precursors of 15N enrichments found in comets and meteorites. Chemical model calculations indicate that atom-molecular ion and ion-molecule reactions could account for most of the fractionation patterns observed. However, recent quantum-chemical computations demonstrate that several of the key processes are unlikely to occur in dense clouds. Related model calculations of dense cloud chemistry show that the revised 15N enrichments fail to match observed values. We have investigated the effects of these reaction rate modifications on the chemical model of Wirström et al. (2012) for which there are significant physical and chemical differences with respect to other models. We have included 15N fractionation of CN in neutral-neutral reactions and also updated rate coefficients for key reactions in the nitrogen chemistry. We find that the revised fractionation rates have the effect of suppressing 15N enrichment in ammonia at all times, while the depletion is even more pronounced, reaching 14N/15N ratios of >2000. Taking the updated nitrogen chemistry into account, no significant enrichment occurs in HCN or HNC, contrary to observational evidence in dark clouds and comets, although the 14N/15N ratio can still be below 100 in CN itself. However, such low CN abundances are predicted that the updated model falls short of explaining the bulk 15N enhancements observed in primitive materials. It is clear that alternative fractionating reactions are necessary to reproduce observations, so further laboratory and theoretical studies are urgently needed.
Oxygen isotopic fractionation during bacterial sulfate reduction
Balci, N.; Turchyn, A. V.; Lyons, T.; Bruchert, V.; Schrag, D. P.; Wall, J.
2006-12-01
Sulfur isotope fractionation during bacterial sulfate reduction (BSR) is understood to depend on a variety of environmental parameters, such as sulfate concentration, temperature, cell specific sulfate reduction rates, and the carbon substrate. What controls oxygen isotope fractionation during BSR is less well understood. Some studies have suggested that carbon substrate is important, whereas others concluded that there is a stoichiometric relationship between the fractionations of sulfur and oxygen during BSR. Studies of oxygen fractionation are complicated by isotopic equilibration between sulfur intermediates, particularly sulfite, and water. This process can modify the isotopic composition of the extracellular sulfate pool (δ18OSO4 ). Given this, the challenge is to distinguish between this isotopic equilibration and fractionations linked to the kinetic effects of the intercellular enzymes and the incorporation of sulfate into the bacterial cell. The δ18OSO4 , in concert with the sulfur isotope composition of sulfate (δ34SSO4), could be a powerful tool for understanding the pathways and environmental controls of BSR in natural systems. We will present δ18OSO4 data measured from batch culture growth of 14 different species of sulfate reducing bacteria for which sulfur isotope data were previously published. A general observation is that δ18OSO4 shows little isotopic change (kinetic effect during BSR and/or equilibration between sulfur intermediates and the isotopically light water (~-5‰) of the growth medium. Our present batch culture data do not allow us to convincingly isolate the magnitude and the controlling parameters of the kinetic isotope effect for oxygen. However, ongoing growth of mutant bacteria missing enzymes critical in the different steps of BSR may assist in this mission.
Advanced techniques for modeling avian nest survival
Dinsmore, S.J.; White, Gary C.; Knopf, F.L.
2002-01-01
Estimation of avian nest survival has traditionally involved simple measures of apparent nest survival or Mayfield constant-nest-survival models. However, these methods do not allow researchers to build models that rigorously assess the importance of a wide range of biological factors that affect nest survival. Models that incorporate greater detail, such as temporal variation in nest survival and covariates representative of individual nests represent a substantial improvement over traditional estimation methods. In an attempt to improve nest survival estimation procedures, we introduce the nest survival model now available in the program MARK and demonstrate its use on a nesting study of Mountain Plovers (Charadrius montanus Townsend) in Montana, USA. We modeled the daily survival of Mountain Plover nests as a function of the sex of the incubating adult, nest age, year, linear and quadratic time trends, and two weather covariates (maximum daily temperature and daily precipitation) during a six-year study (1995–2000). We found no evidence for yearly differences or an effect of maximum daily temperature on the daily nest survival of Mountain Plovers. Survival rates of nests tended by female and male plovers differed (female rate = 0.33; male rate = 0.49). The estimate of the additive effect for males on nest survival rate was 0.37 (95% confidence limits were 0.03, 0.71) on a logit scale. Daily survival rates of nests increased with nest age; the estimate of daily nest-age change in survival in the best model was 0.06 (95% confidence limits were 0.04, 0.09) on a logit scale. Daily precipitation decreased the probability that the nest would survive to the next day; the estimate of the additive effect of daily precipitation on the nest survival rate was −1.08 (95% confidence limits were −2.12, −0.13) on a logit scale. Our approach to modeling daily nest-survival rates allowed several biological factors of interest to be easily included in nest survival models
A highly purified vegetal fraction able to modulate HMGB1 and to attenuate septic shock in mice.
Apetrei, Natalia Simona; Călugăru, Ana; Kerek, F; Panteli, Minerva; Rasit, I; Cremer, Lidia; Szegli, G; Lupu, Andreea-Roxana
2011-01-01
High-mobility group box protein 1 (HMGB1) is an intracellular protein that may be released actively from monocytes and macrophages or passively from necrotic or damaged cells. Its inhibition in animal experiments, even in the late phase of septic shock, significantly enhanced the survival rate of rodents. The aim of our study was to investigate the effect of a vegetal fraction isolated and highly purified from Helleborus purpurascens regarding the modulation of HMGB1 release either from tumor cells or human blood mononuclear cells. Our results showed that the vegetal fraction was able to down-regulate the release of HMGB1 from activated human blood mononuclear cells (PBMCs) and tumor cells. By combining the purified fraction with Cyclophosphamide the release of HMGB1 from tumor cells was strongly decreased. This synergism was not noticed when the ve getal product was associated with Doxorubicin. We also studied the effect of the purified fraction in mice with septic shock induced by cecal ligation and puncture (CLP) method. The tested vegetal product increased significantly the survival rate of animals compared to the mice not treated with it. Our data suggest that the purified vegetal fraction may modulate inflammation by down-regulating the HMGB1, which can also explain its efficacy in septic shock in mice.
Three algorithms for Egyptian fractions | Izevbizua | Journal of the ...
African Journals Online (AJOL)
This idea let them represent any fraction a/b as the sum of unit fractions e.g 27 = 14 + 128. Further, the same fraction could not be used twice (so 27 = 17 + 17 is not allowed). In this work we examine a number of algorithms for generating Egyptian fractions in more detail, implement them and analyze their performance.
21 CFR 862.1630 - Protein (fractionation) test system.
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Protein (fractionation) test system. 862.1630... Systems § 862.1630 Protein (fractionation) test system. (a) Identification. A protein (fractionation) test system is a device intended to measure protein fractions in blood, urine, cerebrospinal fluid, and other...
Improving Children's Knowledge of Fraction Magnitudes
Fazio, Lisa K.; Kennedy, Casey A.; Siegler, Robert S.
2016-01-01
We examined whether playing a computerized fraction game, based on the integrated theory of numerical development and on the Common Core State Standards' suggestions for teaching fractions, would improve children's fraction magnitude understanding. Fourth and fifth-graders were given brief instruction about unit fractions and played "Catch…
Some fractional and multifractional Gaussian processes: A brief introduction
Lim, S. C.; Eab, C. H.
2015-01-01
This paper gives a brief introduction to some important fractional and multifractional Gaussian processes commonly used in modelling natural phenomena and man-made systems. The processes include fractional Brownian motion (both standard and the Riemann-Liouville type), multifractional Brownian motion, fractional and multifractional Ornstein-Uhlenbeck processes, fractional and mutifractional Reisz-Bessel motion. Possible applications of these processes are briefly mentioned.
Integrable coupling system of fractional soliton equation hierarchy
Energy Technology Data Exchange (ETDEWEB)
Yu Fajun, E-mail: yfajun@163.co [College of Maths and Systematic Science, Shenyang Normal University, Shenyang 110034 (China)
2009-10-05
In this Letter, we consider the derivatives and integrals of fractional order and present a class of the integrable coupling system of the fractional order soliton equations. The fractional order coupled Boussinesq and KdV equations are the special cases of this class. Furthermore, the fractional AKNS soliton equation hierarchy is obtained.
Fractional Low-Order Joint Moments in the Estimation of Fractional Motions
Carsteanu, Alin Andrei; Guzman Sanluis, Javier Allan; Delvia Borjas López, Ada
2017-04-01
Fractional motions arise naturally from the integration of fractional noises, signals that appear in a variety of geophysical processes. When the marginal limiting probability distributions of these processes are Gaussian, the scaling behaviour of integer moments, be they marginal or joint - such as linear autocorrelation - can be used to parameterize the process. When, however, those moments do not converge, due to the heavy tails of the distributions, fractional low-order moments offer an attractive alternative. An application thereof to hydrometeorological data is presented herein.
The Use of Fractional Cards for Fraction Learning in The Fifth Grade Students of Elementary School
Directory of Open Access Journals (Sweden)
Ari Indriani
2016-01-01
Full Text Available This research aims to investigate the use of fractional cards on teaching in the fifth grade students of Elementary School. The method used is descriptive qualitative. The researcher used observation, interview, and documentation to collect the data. The results showed that there was an increase on the students' enthusiasm for learning process, and there were 27 students (69.23% that have a score above the Minimum Criteria of Mastery (Kriteria Ketuntasan Minimal/KKM. The study concludes that the use of fractional cards able to help the learning process on the fractions material of the fifth grade students of Elementary School.
Survival patterns and hemopathological responses of dogs under continuous gamma irradiation
International Nuclear Information System (INIS)
Seed, T.M.; Fritz, T.E.; Tolle, D.V.; Poole, C.M.; Lombard, L.S.; Doyle, D.E.; Kaspar, L.V.; Cullen, S.M.; Carnes, B.A.
1983-01-01
Survival curves were constructed and analyzed relative to contributing hematopathological responses for groups of beagles exposed continuously for duration of life to low daily doses of whole body 60 Co gamma irradiation (27.3 rads/day to 4 rads/day). The survival curves versus time were progressively displaced toward longer survival as rates of exposure were reduced from the relatively high dose rate of 27.3 rads/day to the low dose rate of 4.0 rads/day. Average survival times increased from 57 days at 27.3 rads/day to 1830 days at 4.0 rads/day, representing fractional increased life-spans from 1.5% to 50.8%, respectively. Survival curves versus total dose were markedly displaced along the cumulative radiation dose axis at the extreme dose rates (i.e., 27.3 and 4.0 rads/day), but not at the intermediate dose rates (i.e., 13.4 and 7.9 rads/day) in which the upper linear portions of the survival curves are superimposed. From these dose-dependent survival curves, LD 50 values for whole body gamma irradiation, delivered chronically at 27.3, 13.4, 7.9, and 4.0 rads per day were estimated to be 1442, 2124, 2039, and 7161 rads, respectively. Both time- and dose-dependent survival curves for the intermediate dose rates, in contrast to the extreme dose rates, exhibited pronounced transitions in the lethality rate below the 50% survival level. These lethality rate transitions occurred at approx. 2500 rads of accumulated dose and were attributed to a shift in the spectrum of developing hematopathologies: namely, from a predominance of the acutely ablative radiation-induced lymphohematopoietic syndromes (i.e., septicemias and aplastic anemias) to a predominance of the late arising hematopoietic neoplasias (myelogenous leukemia and related myeloproliferative disorders)
[Ciguatera: neurophysiological demonstration of toxicity of several ciquatoxic fractions].
Faucomprez, C; Ferezou, J P; Bagnis, R; Chanfour, B; Niaussat, P M; Drouet, J
1975-01-01
Raw extracts from one Polynesian, frequently ciguatera-inducing fish were submitted to fractional distillation by means of a chromatographic process using a silicic acid column. Three out of the seven fractions split this way exhibited either anticholinesterasic properties, or directly toxic properties at the muscle-cell level: fraction 5, which is not antagonized by atropine, presumably accounts for this direct action, as it competes with calcium at membrane sites. Fraction 6 appears to be more specially responsible for the anticholinesterasic action. It revealed a quaternary ammonium ion in its 6-2 sub-fraction. Fraction 7 shows the same properties as fraction 6, but on a smaller scale.
State-Space Modelling of Loudspeakers using Fractional Derivatives
DEFF Research Database (Denmark)
King, Alexander Weider; Agerkvist, Finn T.
2015-01-01
This work investigates the use of fractional order derivatives in modeling moving-coil loudspeakers. A fractional order state-space solution is developed, leading the way towards incorporating nonlinearities into a fractional order system. The method is used to calculate the response of a fractio......This work investigates the use of fractional order derivatives in modeling moving-coil loudspeakers. A fractional order state-space solution is developed, leading the way towards incorporating nonlinearities into a fractional order system. The method is used to calculate the response...... of a fractional harmonic oscillator, representing the mechanical part of a loudspeaker, showing the effect of the fractional derivative and its relationship to viscoelasticity. Finally, a loudspeaker model with a fractional order viscoelastic suspension and fractional order voice coil is fit to measurement data...
Ultrastructural morphometry of parotid acinar cells following fractionated irradiation
International Nuclear Information System (INIS)
Grehn, A.-L.; Gustafsson, H.; Franzen, L.; Thornell, L.-E.; Henriksson, R.
1997-01-01
The aim of this study was to evaluate the long term effects on the ultrastructure of parotid glands after fractionated irradiation. The method implemented involved 5 x 6 Gy and 5 x 8 Gy, Monday to Friday 6 MV photons. By unilateral irradiation, the contralateral parotid gland served as a control. Although irradiation diminished the acinar cell density in light microscopic sections from 75 to 32% after 5 x 8 Gy of irradiation, ultrastructural morphometry could not detect any statistically significant differences in acinar cell size, nuclear size, nuclear density, granule area, mean granule size, or granule density. In general, greater differences were seen between rats receiving 30 or 40 Gy, on both the irradiated and the control side, than between the irradiated side and the control side. This was interpreted as due to differences in the nutritional state of the animals. This analysis concluded that individual acinar cells that survive irradiation seem not to be damaged in the long term when evaluated at the ultrastructural level. The study further stresses the importance of adequate sampling sizes and the use of adequate controls. (author)
Spironolactone in patients with heart failure and preserved ejection fraction.
Sánchez-Sánchez, C; Mendoza-Ruiz de Zuazu, H F; Formiga, F; Manzano, L; Ceresuela, L M; Carrera-Izquierdo, M; González Franco, Á; Epelde-Gonzalo, F; Cerqueiro-González, J M; Montero-Pérez-Barquero, M
2015-01-01
Aldosterone inhibitors have been shown to be beneficial for patients with systolic heart failure. However, the evidence from patients with heart failure and preserved ejection fraction (HFPEF) is limited. We evaluated the role of spironolactone in the prognosis of a cohort of patients with HFPEF. We analyzed the outcomes of patients hospitalized for HFPEF in 52 departments of internal medicine of the Spanish RICA registry according to those who did and did not take spironolactone. We recorded the posthospital mortality rate and readmissions at 1 year and performed a multivariate survival analysis. We included 1212 patients with HFPEF, with a mean age of 79 years (standard deviation, 7.9), (64.1% women), the majority of whom had hypertensive heart disease (50.7%). The patients treated with spironolactone, compared with those who were not treated with this diuretic, had a more advanced functional class, a higher number of readmissions (44.3 vs. 29.1%; p<0.001) and a higher rate in the combined variable of readmissions/mortality (39.0 vs. 29.0%; p=0.001). In the multivariate analysis, the administration of spironolactone was associated with an increase in readmissions (RR, 1.4; 95% CI, 1.16-1.78; p=0.001). For patients with HFPEF, the administration of spironolactone was associated with an increase in all-cause readmission, perhaps due to the higher rate of hyperpotassemia. Copyright © 2015. Published by Elsevier España, S.L.U.
Lesotho: the politics of survival.
Lye, W F
1982-01-01
In this discussion of the politics of survival in Lesotho, attention is directed to the historical foundations; the road to dependency, the emergence of a political economy; and political transitions. The 1.25 million citizens of Lesotho enjoy a precarious independence. In November 1981, the government welcomed Russian military advisers. Presumably the reason for this was to help defend itself against the Republic of South Africa. This action was only the most recent of a series of increasingly hostile acts and verbal barrages which confirm the persistent aversion of Lesotho toward South Africa. The behavior contrasts markedly with an equally persistent pattern, that of continuous consultations between the Prime Minister of Lesotho since independence in 1966 and every leader of South Africa. The fact that some 200,000 Sotho workers, almost 1/6 of the nation's populaton, cross annually into South Africa to earn their only possible means of income lends a special character to this relationship. It reveals both the depth of Lesotho's aversion while equally affirming its reluctant dependence. It also illuminates a reciprocal need on the part of South Africa, which causes them to tolerate the irritant. The key to understanding the recent history of Lesotho lies with this fundamental interdependence and aversion. In the context of declining living standards at home and the demand for labor by South Africa, at first on the nearby farms and after 1867 in the mines and cities, Lesotho's economy became increasingly subject to political forces beyond its control. During even the early days of Moshoeshoe's reign, he encouraged youths to leave their families to obtain work among the aliens. His original objective was to have the youths learn useful new techniques which could be applied to enrich Lesotho beyond the few coins they might earn. The central focus of foreign employment before long became routine jobs in the mines. By the last decade of the 19th century, Lesotho
Myxobacteria: moving, killing, feeding, and surviving together
Directory of Open Access Journals (Sweden)
José eMuñoz-Dorado
2016-05-01
Full Text Available Myxococcus xanthus, like other myxobacteria, is a social bacterium that moves and feeds cooperatively in predatory groups. On surfaces, rod-shaped vegetative cells move in search of the prey in a coordinated manner, forming dynamic multicellular groups referred to as swarms. Within the swarms, cells interact with one another and use two separate locomotion systems. Adventurous motility, which drives the movement of individual cells, is associated with the secretion of slime that forms trails at the leading edge of the swarms. It has been proposed that cellular traffic along these trails contributes to M. xanthus social behavior via stigmergic regulation. However, most of the cells travel in groups by using social motility, which is cell contact-dependent and requires a large number of individuals. Exopolysaccharides and the retraction of type IV pili at alternate poles of the cells are the engines associated with social motility. When the swarms encounter prey, the population of M. xanthus lyses and takes up nutrients from nearby cells. This cooperative and highly density-dependent feeding behavior has the advantage that the pool of hydrolytic enzymes and other secondary metabolites secreted by the entire group is shared by the community to optimize the use of the degradation products. This multicellular behavior is especially observed in the absence of nutrients. In this condition, M. xanthus swarms have the ability to organize the gliding movements of thousands of rods, synchronizing rippling waves of oscillating cells, to form macroscopic fruiting bodies, with three subpopulations of cells showing division of labor. A small fraction of cells either develop into resistant myxospores or remain as peripheral rods, while the majority of cells die, probably to provide nutrients to allow aggregation and spore differentiation. Sporulation within multicellular fruiting bodies has the benefit of enabling survival in hostile environments, and increases
Impedance matching through a single passive fractional element
Radwan, Ahmed Gomaa
2012-07-01
For the first time, a generalized admittance Smith chart theory is introduced to represent fractional order circuit elements. The principles of fractional order matching circuits are described. We show that for fractional order α < 1, a single parallel fractional element can match a wider range of load impedances as compared to its series counterpart. Several matching examples demonstrate the versatility of fractional order series and parallel element matching as compared to the conventional approach. © 2012 IEEE.
Cauchy-Kovalevskaya extension theorem in fractional Clifford analysis
Vieira, Nelson
2015-01-01
In this paper, we establish the fractional Cauchy-Kovalevskaya extension (FCK-extension) theorem for fractional monogenic functions defined on R^d. Based on this extension principle, fractional Fueter polynomials, forming a basis of the space of fractional spherical monogenics, i.e. fractional homogeneous polynomials, are introduced. We studied the connection between the FCK-extension of functions of the form x^\\alpha P_l and the classical Gegenbauer polynomials. Finally we present two examp...
Stability analysis of distributed order fractional chen system.
Aminikhah, H; Refahi Sheikhani, A; Rezazadeh, H
2013-01-01
We first investigate sufficient and necessary conditions of stability of nonlinear distributed order fractional system and then we generalize the integer-order Chen system into the distributed order fractional domain. Based on the asymptotic stability theory of nonlinear distributed order fractional systems, the stability of distributed order fractional Chen system is discussed. In addition, we have found that chaos exists in the double fractional order Chen system. Numerical solutions are used to verify the analytical results.
Stability Analysis of Distributed Order Fractional Chen System
Aminikhah, H.; Refahi Sheikhani, A.; Rezazadeh, H.
2013-01-01
We first investigate sufficient and necessary conditions of stability of nonlinear distributed order fractional system and then we generalize the integer-order Chen system into the distributed order fractional domain. Based on the asymptotic stability theory of nonlinear distributed order fractional systems, the stability of distributed order fractional Chen system is discussed. In addition, we have found that chaos exists in the double fractional order Chen system. Numerical solutions are used to verify the analytical results. PMID:24489508
Semianalytic Solution of Space-Time Fractional Diffusion Equation
Directory of Open Access Journals (Sweden)
A. Elsaid
2016-01-01
Full Text Available We study the space-time fractional diffusion equation with spatial Riesz-Feller fractional derivative and Caputo fractional time derivative. The continuation of the solution of this fractional equation to the solution of the corresponding integer order equation is proved. The series solution of this problem is obtained via the optimal homotopy analysis method (OHAM. Numerical simulations are presented to validate the method and to show the effect of changing the fractional derivative parameters on the solution behavior.