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Sample records for 53bp1 focus formation

  1. Differences in quantification of DNA double-strand breaks assessed by 53BP1/γH2AX focus formation assays and the comet assay in mammalian cells treated with irradiation and N-acetyl-L-cysteine

    Kurashige, Tomomi; Shimamura, Mika; Nagayama, Yuji

    2016-01-01

    The biological effect of ionizing radiation (IR) on genomic DNA is thought to be either direct or indirect; the latter is mediated by IR induction of free radicals and reactive oxygen species (ROS). This study was designed to evaluate the effect of N-acetyl-L-cysteine (NAC), a well-known ROS-scavenging antioxidant, on IR induction of genotoxicity, cytotoxicity and ROS production in mammalian cells, and aimed to clarify the conflicting data in previous publications. Although we clearly demonstrate the beneficial effect of NAC on IR-induced genotoxicity and cytotoxicity (determined using the micronucleus assay and cell viability/clonogenic assays), the data on NAC's effect on DNA double-strand break (DSB) formation were inconsistent in different assays. Specifically, mitigation of IR-induced DSBs by NAC was readily detected by the neutral comet assay, but not by the γH2AX or 53BP1 focus assays. NAC is a glutathione precursor and exerts its effect after conversion to glutathione, and presumably it has its own biological activity. Assuming that the focus assay reflects the biological responses to DSBs (detection and repair), while the comet assay reflects the physical status of genomic DNA, our results indicate that the comet assay could readily detect the antioxidant effect of NAC on DSB formation. However, NAC's biological effect might affect the detection of DSB repair by the focus assays. Our data illustrate that multiple parameters should be carefully used to analyze DNA damage when studying potential candidates for radioprotective compounds. PMID:26951077

  2. Analysis of Lymphocytic DNA Damage in Early Multiple Sclerosis by Automated Gamma-H2AX and 53BP1 Foci Detection: A Case Control Study

    Rasche, Ludwig; Heiserich, Lisa; Behrens, Janina Ruth; Lenz, Klaus; Pfuhl, Catherina; Wakonig, Katharina; Gieß, René Markus; Freitag, Erik; Eberle, Caroline; Wuerfel, Jens; Dörr, Jan; Bauer, Peter; Bellmann-Strobl, Judith; Paul, Friedemann; Roggenbuck, Dirk; Ruprecht, Klemens

    2016-01-01

    Background In response to DNA double-strand breaks, the histone protein H2AX becomes phosphorylated at its C-terminal serine 139 residue, referred to as γ-H2AX. Formation of γ-H2AX foci is associated with recruitment of p53-binding protein 1 (53BP1), a regulator of the cellular response to DNA double-strand breaks. γ-H2AX expression in peripheral blood mononuclear cells (PBMCs) was recently proposed as a diagnostic and disease activity marker for multiple sclerosis (MS). Objective To evaluate the significance of γ-H2AX and 53BP1 foci in PBMCs as diagnostic and disease activity markers in patients with clinically isolated syndrome (CIS) and early relapsing-remitting MS (RRMS) using automated γ-H2AX and 53BP1 foci detection. Methods Immunocytochemistry was performed on freshly isolated PBMCs of patients with CIS/early RRMS (n = 25) and healthy controls (n = 27) with γ-H2AX and 53BP1 specific antibodies. Nuclear γ-H2AX and 53BP1 foci were determined using a fully automated reading system, assessing the numbers of γ-H2AX and 53BP1 foci per total number of cells and the percentage of cells with foci. Patients underwent contrast enhanced 3 Tesla magnetic resonance imaging (MRI) and clinical examination including expanded disability status scale (EDSS) score. γ-H2AX and 53BP1 were also compared in previously frozen PBMCs of each 10 CIS/early RRMS patients with and without contrast enhancing lesions (CEL) and 10 healthy controls. Results The median (range) number of γ-H2AX (0.04 [0–0.5]) and 53BP1 (0.005 [0–0.2]) foci per cell in freshly isolated PBMCs across all study participants was low and similar to previously reported values of healthy individuals. For both, γ-H2AX and 53BP1, the cellular focus number as well as the percentage of positive cells did not differ between patients with CIS/RRMS and healthy controls. γ-H2AX and 53BP1 levels neither correlated with number nor volume of T2-weighted lesions on MRI, nor with the EDSS. Although γ-H2AX, but not

  3. A Damage-Independent Role for 53BP1 that Impacts Break Order and Igh Architecture during Class Switch Recombination

    Pedro P. Rocha

    2016-06-01

    Full Text Available During class switch recombination (CSR, B cells replace the Igh Cμ or δ exons with another downstream constant region exon (CH, altering the antibody isotype. CSR occurs through the introduction of AID-mediated double-strand breaks (DSBs in switch regions and subsequent ligation of broken ends. Here, we developed an assay to investigate the dynamics of DSB formation in individual cells. We demonstrate that the upstream switch region Sμ is first targeted during recombination and that the mechanism underlying this control relies on 53BP1. Surprisingly, regulation of break order occurs through residual binding of 53BP1 to chromatin before the introduction of damage and independent of its established role in DNA repair. Using chromosome conformation capture, we show that 53BP1 mediates changes in chromatin architecture that affect break order. Finally, our results explain how changes in Igh architecture in the absence of 53BP1 could promote inversional rearrangements that compromise CSR.

  4. A Damage-Independent Role for 53BP1 that Impacts Break Order and Igh Architecture during Class Switch Recombination.

    Rocha, Pedro P; Raviram, Ramya; Fu, Yi; Kim, JungHyun; Luo, Vincent M; Aljoufi, Arafat; Swanzey, Emily; Pasquarella, Alessandra; Balestrini, Alessia; Miraldi, Emily R; Bonneau, Richard; Petrini, John; Schotta, Gunnar; Skok, Jane A

    2016-06-28

    During class switch recombination (CSR), B cells replace the Igh Cμ or δ exons with another downstream constant region exon (CH), altering the antibody isotype. CSR occurs through the introduction of AID-mediated double-strand breaks (DSBs) in switch regions and subsequent ligation of broken ends. Here, we developed an assay to investigate the dynamics of DSB formation in individual cells. We demonstrate that the upstream switch region Sμ is first targeted during recombination and that the mechanism underlying this control relies on 53BP1. Surprisingly, regulation of break order occurs through residual binding of 53BP1 to chromatin before the introduction of damage and independent of its established role in DNA repair. Using chromosome conformation capture, we show that 53BP1 mediates changes in chromatin architecture that affect break order. Finally, our results explain how changes in Igh architecture in the absence of 53BP1 could promote inversional rearrangements that compromise CSR. PMID:27320916

  5. Ser1778 of 53BP1 Plays a Role in DNA Double-strand Break Repairs

    Lee, Jung-Hee; Cheong, Hyang-Min; Kang, Mi-Young; Kim, Sang-Young; Kang, Yoonsung

    2009-01-01

    53BP1 is an important genome stability regulator, which protects cells against double-strand breaks. Following DNA damage, 53BP1 is rapidly recruited to sites of DNA breakage, along with other DNA damage response proteins, including γ-H2AX, MDC1, and BRCA1. The recruitment of 53BP1 requires a tandem Tudor fold which associates with methylated histones H3 and H4. It has already been determined that the majority of DNA damage response proteins are phosphorylated by ATM and/or ATR after DNA dama...

  6. DNA damage foci in mitosis are devoid of 53BP1.

    Nelson, Glyn; Buhmann, Matthias; von Zglinicki, Thomas

    2009-10-15

    Nuclear DNA damage foci indicate ongoing DNA damage response, which is the major inducer of cell cycle arrest, cellular senescence and apoptosis. 53BP1 is one central mediator of the DNA damage response and a component of active DNA damage foci. Using an AcGFP-53BP1c fluorescent fusion protein that quantitatively reports DNA damage, we show that the recruitment of 53BP1 into gammaH2A.X-containing DNA damage foci was inhibited at G(2)/M. This suggests a possible mechanism for cells to continue through the G(2) checkpoint with gammaH2A.X-flagged double strand breaks via inhibition of 53BP1-mediated DNA damage signalling. PMID:19806024

  7. 53BP1 mediates productive and mutagenic DNA repair through distinct phosphoprotein interactions

    Callen, E.; Wong, N.; Chen, H.-T.;

    2013-01-01

    The DNA damage response (DDR) protein 53BP1 protects DNA ends from excessive resection in G1, and thereby favors repair by nonhomologous end-joining (NHEJ) as opposed to homologous recombination (HR). During S phase, BRCA1 antagonizes 53BP1 to promote HR. The pro-NHEJ and antirecombinase functions...... productive CSR and suppresses mutagenic DNA repair through distinct phosphodependent interactions with RIF1 and PTIP. © 2013 Elsevier Inc....

  8. BRCA1 loss activates cathepsin L–mediated degradation of 53BP1 in breast cancer cells

    Grotsky, David A.; González-Suárez, Ignacio; Novell Álvarez, Anna; Neumann, Martin; Yaddanapudi, Sree C.; Croke, Monica; Martínez Alonso, Montserrat; Redwood, Abena B.; Ortega-Martinez, Sylvia; Feng, Zhihui; Lerma, Enrique; Ramon y Cajal, Teresa; Zhang, Junran; Matias-Guiu, Xavier; Dusso, Adriana

    2013-01-01

    Loss of 53BP1 rescues BRCA1 deficiency and is associated with BRCA1-deficient and triple-negative breast cancers (TNBC) and with resistance to genotoxic drugs. The mechanisms responsible for decreased 53BP1 transcript and protein levels in tumors remain unknown. Here, we demonstrate that BRCA1 loss activates cathepsin L (CTSL)–mediated degradation of 53BP1. Activation of this pathway rescued homologous recombination repair and allowed BRCA1-deficient cells to bypass growth arrest. Importantly...

  9. Ectopic expression of RNF168 and 53BP1 increases mutagenic but not physiological non-homologous end joining

    Zong, Dali; Callén, Elsa; Pegoraro, Gianluca;

    2015-01-01

    -resection activities of 53BP1 are rate-limiting for mutagenic NHEJ but not for physiological CSR. As heterogeneity in the expression of RNF168 and 53BP1 is found in human tumors, our results suggest that deregulation of the RNF168/53BP1 pathway could alter the chemosensitivity of BRCA1 deficient tumors....... instability. Recently, it was shown that supra-physiological levels of the E3 ubiquitin ligase RNF168 results in the hyper-accumulation of 53BP1/BRCA1 which accelerates DSB repair. Here, we ask whether increased expression of RNF168 or 53BP1 impacts physiological versus mutagenic NHEJ. We find that the anti...

  10. Role of 53BP1 in the regulation of DNA double-strand break repair pathway choice.

    Gupta, Arun; Hunt, Clayton R; Chakraborty, Sharmistha; Pandita, Raj K; Yordy, John; Ramnarain, Deepti B; Horikoshi, Nobuo; Pandita, Tej K

    2014-01-01

    The p53-binding protein 1 (53BP1) is a well-known DNA damage response (DDR) factor, which is recruited to nuclear structures at the site of DNA damage and forms readily visualized ionizing radiation (IR) induced foci. Depletion of 53BP1 results in cell cycle arrest in G2/M phase as well as genomic instability in human as well as mouse cells. Within the DNA damage response mechanism, 53BP1 is classified as an adaptor/mediator, required for processing of the DNA damage response signal and as a platform for recruitment of other repair factors. More recently, specific 53BP1 contributions to DSB repair pathway choice have been recognized and are being characterized. In this review, we have summarized recent advances in understanding the role of 53BP1 in regulating DNA DSBs repair pathway choice, variable diversity joining [V(D)J] recombination and class-switch recombination (CSR). PMID:24320053

  11. ATM-dependent phosphorylation of 53BP1 in response to genomic stress in oxic and hypoxic cells

    The ATM kinase is activated by chromatin modification following exogenous and endogenous DSBs or cell stress, including acute anoxia. The p53 binding protein 1 (53BP1) contains multiple ATM-consensus phosphorylation sites in its N- and C-termini and may therefore be a distal read-out of ATM function. We have examined the cellular activation of these phosphorylation sites for the first time in situ following anoxic/hypoxic stress and IR-induced exogenous DSBs. We show that multiple residues of 53BP1 are phosphorylated and that these phosphoforms form discrete nuclear foci following IR or during DNA replication as exogenous or endogenous DNA double strand breaks (DSBs), respectively. Novel data pertaining to the phosphorylation of 53BP1Ser25in situ supports its dependency on the ATM kinase; but this occurs independently of p53 function. We show that 53BP1Ser25 is activated specifically in S-phase cells during anoxia in an ATM-dependent manner. Exogenous DSBs form discrete IR-induced foci whereas oxygen stress induced non-localized 53BP1Ser25 activation. Our in vitro data are supported by irradiated xenograft studies in vivo whereby 53BP1Ser25 phosphorylation does not occur in sub-regions positive for the hypoxia marker EF5. We propose a model whereby DSBs induce chromatin modification at sites of DNA damage which are tracked by the ATM substrates γ H2AX and 53BP1Ser25 in a mechanism distinct from p53-mediated cell cycle arrest. Together this work indicates 53BP1Ser25, and possibly other 53BP1 phosphoforms, as a bona fide DSB-biomarkers for surveying ongoing DNA-damage related signaling in oxic and hypoxic cells during clinical radiotherapy.

  12. Tying the loose ends together in DNA double strand break repair with 53BP1

    Carpenter Phillip B

    2006-08-01

    Full Text Available Abstract To maintain genomic stability and ensure the fidelity of chromosomal transmission, cells respond to various forms of genotoxic stress, including DNA double-stranded breaks (DSBs, through the activation of DNA damage response signaling networks. In response to DSBs as induced by ionizing radiation (IR, during DNA replication, or through immunoglobulin heavy chain (IgH rearrangements in B cells of lymphoid origin, the phosphatidyl inositol-like kinase (PIK kinases ATM (mutated in ataxia telangiectasia, ATR (ATM and Rad3-related kinase, and the DNA-dependent protein kinase (DNA-PK activate signaling pathways that lead to DSB repair. DSBs are repaired by either of two major, non-mutually exclusive pathways: homologous recombination (HR that utilizes an undamaged sister chromatid template (or homologous chromosome and non- homologous end joining (NHEJ, an error prone mechanism that processes and joins broken DNA ends through the coordinated effort of a small set of ubiquitous factors (DNA-PKcs, Ku70, Ku80, artemis, Xrcc4/DNA lig IV, and XLF/Cernunnos. The PIK kinases phosphorylate a variety of effector substrates that propagate the DNA damage signal, ultimately resulting in various biological outputs that influence cell cycle arrest, transcription, DNA repair, and apoptosis. A variety of data has revealed a critical role for p53-binding protein 1 (53BP1 in the cellular response to DSBs including various aspects of p53 function. Importantly, 53BP1 plays a major role in suppressing translocations, particularly in B and T cells. This report will review past experiments and current knowledge regarding the role of 53BP1 in the DNA damage response.

  13. Tying the loose ends together in DNA double strand break repair with 53BP1.

    Adams, Melissa M; Carpenter, Phillip B

    2006-01-01

    To maintain genomic stability and ensure the fidelity of chromosomal transmission, cells respond to various forms of genotoxic stress, including DNA double-stranded breaks (DSBs), through the activation of DNA damage response signaling networks. In response to DSBs as induced by ionizing radiation (IR), during DNA replication, or through immunoglobulin heavy chain (IgH) rearrangements in B cells of lymphoid origin, the phosphatidyl inositol-like kinase (PIK) kinases ATM (mutated in ataxia telangiectasia), ATR (ATM and Rad3-related kinase), and the DNA-dependent protein kinase (DNA-PK) activate signaling pathways that lead to DSB repair. DSBs are repaired by either of two major, non-mutually exclusive pathways: homologous recombination (HR) that utilizes an undamaged sister chromatid template (or homologous chromosome) and non- homologous end joining (NHEJ), an error prone mechanism that processes and joins broken DNA ends through the coordinated effort of a small set of ubiquitous factors (DNA-PKcs, Ku70, Ku80, artemis, Xrcc4/DNA lig IV, and XLF/Cernunnos). The PIK kinases phosphorylate a variety of effector substrates that propagate the DNA damage signal, ultimately resulting in various biological outputs that influence cell cycle arrest, transcription, DNA repair, and apoptosis. A variety of data has revealed a critical role for p53-binding protein 1 (53BP1) in the cellular response to DSBs including various aspects of p53 function. Importantly, 53BP1 plays a major role in suppressing translocations, particularly in B and T cells. This report will review past experiments and current knowledge regarding the role of 53BP1 in the DNA damage response. PMID:16945145

  14. Nucleoporin NUP153 guards genome integrity by promoting nuclear import of 53BP1

    Moudrý, Pavel; Lukas, C.; Macůrek, Libor; Neumann, B.; Heriche, J.K.; Pepperkok, R.; Ellenberg, J.; Hodný, Zdeněk; Lukas, J.; Bartek, Jiří

    2012-01-01

    Roč. 19, č. 5 (2012), s. 798-807. ISSN 1350-9047 R&D Projects: GA ČR GA301/08/0353; GA ČR GAP301/10/1525; GA ČR GPP305/10/P420 Grant ostatní: 7.RP EU(XE) CZ.1.05/2.1.00/01.0030 Institutional research plan: CEZ:AV0Z50520514 Keywords : DNA damage response * NUP153 * 53BP1 nuclear import Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 8.371, year: 2012

  15. Hybrid detectors improved time-lapse confocal microscopy of PML and 53BP1 nuclear body colocalization in DNA lesions.

    Foltánková, Veronika; Matula, Pavel; Sorokin, Dmitry; Kozubek, Stanislav; Bártová, Eva

    2013-04-01

    We used hybrid detectors (HyDs) to monitor the trajectories and interactions of promyelocytic leukemia (GFP-PML) nuclear bodies (NBs) and mCherry-53BP1-positive DNA lesions. 53BP1 protein accumulates in NBs that occur spontaneously in the genome or in γ-irradiation-induced foci. When we induced local DNA damage by ultraviolet irradiation, we also observed accumulation of 53BP1 proteins into discrete bodies, instead of the expected dispersed pattern. In comparison with photomultiplier tubes, which are used for standard analysis by confocal laser scanning microscopy, HyDs significantly eliminated photobleaching of GFP and mCherry fluorochromes during image acquisition. The low laser intensities used for HyD-based confocal analysis enabled us to observe NBs for the longer time periods, necessary for studies of the trajectories and interactions of PML and 53BP1 NBs. To further characterize protein interactions, we used resonance scanning and a novel bioinformatics approach to register and analyze the movements of individual PML and 53BP1 NBs. The combination of improved HyD-based confocal microscopy with a tailored bioinformatics approach enabled us to reveal damage-specific properties of PML and 53BP1 NBs. PMID:23410959

  16. Overlapping functions between XLF repair protein and 53BP1 DNA damage response factor in end joining and lymphocyte development.

    Liu, Xiangyu; Jiang, Wenxia; Dubois, Richard L; Yamamoto, Kenta; Wolner, Zachary; Zha, Shan

    2012-03-01

    Nonhomologous end joining (NHEJ), a major pathway of DNA double-strand break (DSB) repair, is required during lymphocyte development to resolve the programmed DSBs generated during Variable, Diverse, and Joining [V(D)J] recombination. XRCC4-like factor (XLF) (also called Cernunnos or NHEJ1) is a unique component of the NHEJ pathway. Although germ-line mutations of other NHEJ factors abrogate lymphocyte development and lead to severe combined immunodeficiency (SCID), XLF mutations cause a progressive lymphocytopenia that is generally less severe than SCID. Accordingly, XLF-deficient murine lymphocytes show no measurable defects in V(D)J recombination. We reported earlier that ATM kinase and its substrate histone H2AX are both essential for V(D)J recombination in XLF-deficient lymphocytes, despite moderate role in V(D)J recombination in WT cells. p53-binding protein 1 (53BP1) is another substrate of ATM. 53BP1 deficiency led to small reduction of peripheral lymphocyte number by compromising both synapse and end-joining at modest level during V(D)J recombination. Here, we report that 53BP1/XLF double deficiency blocks lymphocyte development at early progenitor stages, owing to severe defects in end joining during chromosomal V(D)J recombination. The unrepaired DNA ends are rapidly degraded in 53BP1(-/-)XLF(-/-) cells, as reported for H2AX(-/-)XLF(-/-) cells, revealing an end protection role for 53BP1 reminiscent of H2AX. In contrast to the early embryonic lethality of H2AX(-/-)XLF(-/-) mice, 53BP1(-/-)XLF(-/-) mice are born alive and develop thymic lymphomas with translocations involving the T-cell receptor loci. Together, our findings identify a unique function for 53BP1 in end-joining and tumor suppression. PMID:22355127

  17. Nanoscopic exclusion between Rad51 and 53BP1 after ion irradiation in human HeLa cells

    Reindl, Judith; Drexler, Guido A.; Girst, Stefanie; Greubel, Christoph; Siebenwirth, Christian; Drexler, Sophie E.; Dollinger, Günther; Friedl, Anna A.

    2015-12-01

    Many proteins involved in detection, signalling and repair of DNA double-strand breaks (DSB) accumulate in large number in the vicinity of DSB sites, forming so called foci. Emerging evidence suggests that these foci are sub-divided in structural or functional domains. We use stimulated emission depletion (STED) microscopy to investigate localization of mediator protein 53BP1 and recombination factor Rad51 after irradiation of cells with low linear energy transfer (LET) protons or high LET carbon ions. With a resolution better than 100 nm, STED microscopy and image analysis using a newly developed analyzing algorithm, the reduced product of the differences from the mean, allowed us to demonstrate that with both irradiation types Rad51 occupies spherical regions of about 200 nm diameter. These foci locate within larger 53BP1 accumulations in regions of local 53BP1 depletion, similar to what has been described for the localization of Brca1, CtIP and RPA. Furthermore, localization relative to 53BP1 and size of Rad51 foci was not different after irradiation with low and high LET radiation. As expected, 53BP1 foci induced by low LET irradiation mostly contained one Rad51 focal structure, while after high LET irradiation, most foci contained >1 Rad51 accumulation.

  18. 53BP1 nuclear bodies form around DNA lesions generated by mitotic transmission of chromosomes under replication stress

    Lukas, Claudia; Savic, Velibor; Bekker-Jensen, Simon;

    2011-01-01

    Completion of genome duplication is challenged by structural and topological barriers that impede progression of replication forks. Although this can seriously undermine genome integrity, the fate of DNA with unresolved replication intermediates is not known. Here, we show that mild replication...... bodies shield chromosomal fragile sites sequestered in these compartments against erosion. Together, these data indicate that restoration of DNA or chromatin integrity at loci prone to replication problems requires mitotic transmission to the next cell generations....... increases after genetic ablation of BLM, a DNA helicase associated with dissolution of entangled DNA. Conversely, 53BP1 nuclear bodies are partially suppressed by knocking down SMC2, a condensin subunit required for mechanical stability of mitotic chromosomes. Finally, we provide evidence that 53BP1 nuclear...

  19. Persistence of gamma-H2AX and 53BP1 foci in proliferating and nonproliferating human mammary epithelial cells after exposure to gamma-rays or iron ions

    Groesser, Torsten; Chang, Hang; Fontenay, Gerald; Chen, James; Costes, Sylvain V.; Barcellos-Hoff, Mary Helen; Parvin, Bahram; Rydberg, Bjorn

    2010-12-22

    To investigate {gamma}-H2AX (phosphorylated histone H2AX) and 53BP1 (tumour protein 53 binding protein No. 1) foci formation and removal in proliferating and non-proliferating human mammary epithelial cells (HMEC) after exposure to sparsely and densely ionizing radiation under different cell culture conditions. HMEC cells were grown either as monolayers (2D) or in extracellular matrix to allow the formation of acinar structures in vitro (3D). Foci numbers were quantified by image analysis at various time points after exposure. Our results reveal that in non-proliferating cells under 2D and 3D cell culture conditions, iron-ion induced {gamma}-H2AX foci were still present at 72 h after exposure, although 53BP1 foci returned to control levels at 48 h. In contrast in proliferating HMEC, both {gamma}-H2AX and 53BP1 foci decreased to control levels during the 24-48 h time interval after irradiation under 2D conditions. Foci numbers decreased faster after {gamma}-ray irradiation and returned to control levels by 12 h regardless of marker, cell proliferation status, and cell culture condition. Conclusions: The disappearance of radiation induced {gamma}-H2AX and 53BP1 foci in HMEC have different dynamics that depend on radiation quality and proliferation status. Notably, the general patterns do not depend on the cell culture condition (2D versus 3D). We speculate that the persistent {gamma}-H2AX foci in iron-ion irradiated non-proliferating cells could be due to limited availability of double strand break (DSB) repair pathways in G0/G1-phase, or that repair of complex DSB requires replication or chromatin remodeling.

  20. ATM Localization and Heterochromatin Repair Depend on Direct Interaction of the 53BP1-BRCT2 Domain with γH2AX

    Robert A. Baldock

    2015-12-01

    Full Text Available 53BP1 plays multiple roles in mammalian DNA damage repair, mediating pathway choice and facilitating DNA double-strand break repair in heterochromatin. Although it possesses a C-terminal BRCT2 domain, commonly involved in phospho-peptide binding in other proteins, initial recruitment of 53BP1 to sites of DNA damage depends on interaction with histone post-translational modifications—H4K20me2 and H2AK13/K15ub—downstream of the early γH2AX phosphorylation mark of DNA damage. We now show that, contrary to current models, the 53BP1-BRCT2 domain binds γH2AX directly, providing a third post-translational mark regulating 53BP1 function. We find that the interaction of 53BP1 with γH2AX is required for sustaining the 53BP1-dependent focal concentration of activated ATM that facilitates repair of DNA double-strand breaks in heterochromatin in G1.

  1. ATM Localization and Heterochromatin Repair Depend on Direct Interaction of the 53BP1-BRCT2 Domain with γH2AX.

    Baldock, Robert A; Day, Matthew; Wilkinson, Oliver J; Cloney, Ross; Jeggo, Penelope A; Oliver, Antony W; Watts, Felicity Z; Pearl, Laurence H

    2015-12-15

    53BP1 plays multiple roles in mammalian DNA damage repair, mediating pathway choice and facilitating DNA double-strand break repair in heterochromatin. Although it possesses a C-terminal BRCT2 domain, commonly involved in phospho-peptide binding in other proteins, initial recruitment of 53BP1 to sites of DNA damage depends on interaction with histone post-translational modifications--H4K20me2 and H2AK13/K15ub--downstream of the early γH2AX phosphorylation mark of DNA damage. We now show that, contrary to current models, the 53BP1-BRCT2 domain binds γH2AX directly, providing a third post-translational mark regulating 53BP1 function. We find that the interaction of 53BP1 with γH2AX is required for sustaining the 53BP1-dependent focal concentration of activated ATM that facilitates repair of DNA double-strand breaks in heterochromatin in G1. PMID:26628370

  2. Low p53 Binding Protein 1 (53BP1) Expression Is Associated With Increased Local Recurrence in Breast Cancer Patients Treated With Breast-Conserving Surgery and Radiotherapy

    Purpose: To investigate whether the expression of p53 binding protein 1 (53BP1) has prognostic significance in a cohort of early-stage breast cancer patients treated with breast-conserving surgery and radiotherapy (BCS+RT). Methods and Materials: A tissue microarray of early-stage breast cancer treated with BCS+RT from a cohort of 514 women was assayed for 53BP1, estrogen receptor, progesterone receptor, and HER2 expression by immunohistochemistry. Through log–rank tests and univariate and multivariate models, the staining profile of each tumor was correlated with clinical endpoints, including ipsilateral breast recurrence–free survival (IBRFS), distant metastasis–free survival (DMFS), cause-specific survival (CSS), recurrence-free survival (RFS), and overall survival (OS). Results: Of the 477 (93%) evaluable tumors, 63 (13%) were scored as low. Low expression of 53BP1 was associated with worse outcomes for all endpoints studied, including 10-year IBRFS (76.8% vs. 90.5%; P=.01), OS (66.4% vs. 81.7%; P=.02), CSS (66.0% vs. 87.4%; P<.01), DMFS (55.9% vs. 87.0%; P<.01), and RFS (45.2% vs. 80.6%; P<.01). Multivariate analysis incorporating various clinico-pathologic markers and 53BP1 expression found that 53BP1 expression was again an independent predictor of all endpoints (IBRFS: P=.0254; OS: P=.0094; CSS: P=.0033; DMFS: P=.0006; RFS: P=.0002). Low 53BP1 expression was also found to correlate with triple-negative (TN) phenotype (P<.01). Furthermore, in subset analysis of all TN breast cancer, negative 53BP1 expression trended for lower IBRFS (72.3% vs. 93.9%; P=.0361) and was significant for worse DMFS (48.2% vs. 86.8%; P=.0035) and RFS (37.8% vs. 83.7%; P=.0014). Conclusion: Our data indicate that low 53BP1 expression is an independent prognostic indicator for local relapse among other endpoints in early-stage breast cancer and TN breast cancer patients treated with BCS+RT. These results should be verified in larger cohorts of patients to validate their

  3. Three-dimensional imaging reveals the spatial separation of γH2AX–MDC1–53BP1 and RNF8–RNF168–BRCA1-A complexes at ionizing radiation-induced foci

    Background and purpose: Ionizing radiation (IR)-induced DNA damage causes the accumulation of DNA damage response (DDR) proteins as visible foci in cell nuclei. Despite the identified functional roles in DNA repair, the spatial relationships of different DDR proteins at foci have not been explicitly examined. This study aims to systematically compare the distribution of DDR proteins at IR-induced foci. Materials and methods: MCF-7 cells were treated with IR, stained for γH2AX, MDC1, RNF8, RNF168, 53BP1, Abraxas (CCDC98), BRCA1, BRCC36, Merit40 (NBA1) and RAP80, and then imaged using high-resolution three-dimensional (3-D) confocal microscopy to assess the relative localization of proteins at foci. Results: All BRCA1-A complex components displayed strong co-localization, which overlapped significantly with RNF8 and RNF168, but not with γH2AX and MDC1. Intriguingly, 53BP1 co-located well with γH2AX and MDC1, but remained separate from RNF8 and RNF168. These co-localization patterns were consistent for at least 3 h after IR. Conclusions: The foci formations of γH2AX–MDC1–53BP1 and RNF8–RNF168–BRCA1-A complexes are spatially independent. Such divergence was not anticipated from prior studies on the recruitment of these proteins to foci. This information indicates that individual foci may represent distinct sites of DNA repair facilitated by a specific subset of DDR proteins.

  4. DNA damage response mediators MDC1 and 53BP1: constitutive activation and aberrant loss in breast and lung cancer, but not in testicular germ cell tumours

    Bartkova, J.; Hořejší, Zuzana; Sehested, M.; Nesland, J.M.; Rajpert-De Meyts, E.; Skakkebaek, N.E.; Stucki, M.; Jackson, S.; Lukas, J.; Bartek, Jiří

    2007-01-01

    Roč. 26, č. 53 (2007), s. 7414-7422. ISSN 0950-9232 Institutional research plan: CEZ:AV0Z50520514 Keywords : DNA damage response * cancer * MDC1 and 53BP1 defects * tumour suppressors Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.440, year: 2007

  5. Assessing ‘radiosensitivity’ with kinetic profiles of γ-H2AX, 53BP1 and BRCA1 foci

    Background and purpose: DNA repair assays to identify radiosensitive patients have had limited clinical implementation due to long turn-around times or limited specificity. This study evaluates γ-H2AX-Irradiation Induced Foci (IRIF) kinetics as a more rapid surrogate for the ‘gold standard’ colony survival assay (CSA) using several known DNA repair disorders as reference models. Materials and methods: Radiosensitive cells of known and unknown etiology were studied. γ-H2AX-IRIFs were quantified over 24 h, and the curves were fitted by combining logarithmic growth and exponential decay functions. Fitted values that differed from radionormal controls were considered aberrant and compared to CSA results. Results: We observed 87% agreement of IRIF data with the CSA for the 14 samples tested. Analysis of γ-H2AX-IRIF kinetics for known repair disorders indicated similarities between an RNF168−/− cell line and an RS cell of unknown etiology. These cell lines were further characterized by a reduction in BRCA1-IRIF formation and G2/M checkpoint activation. Conclusions: γ-H2AX-IRIF kinetics showed high concordance with the CSA in RS populations demonstrating its potential as a more rapid surrogate assay. This method provides a means to globally identify defective DNA repair pathways in RS cells of unknown etiology through comparison with known DNA repair defects.

  6. Evaluation of Single Nucleotide Polymorphisms (SNPs) in the p53 Binding Protein 1 (TP53BP1) Gene in Breast Cancer Patients Treated With Breast-Conserving Surgery and Whole-Breast Irradiation (BCS + RT)

    Purpose: TP53BP1 is a key component of radiation-induced deoxyribonucleic acid damage repair. The purpose of this study was to evaluate the significance of a known common single nucleotide polymorphism in this gene (rs560191) in patients treated with breast-conserving surgery and whole-breast irradiation (BCS + RT). Methods and Materials: The population consisted of 176 premenopausal women treated with BCS + RT (median follow-up, 12 years). Genomic deoxyribonucleic acid was processed by use of TaqMan assays. Each allele for rs560191 was either C or G, so each patient was therefore classified as CC, CG, or GG. Patients were grouped as GG if they were homozygous for the variant G allele or CC-CG if they carried at least one copy of the common C allele (CC or CG). Results: Of the 176 women, 124 (71%) were CC-CG and 52 (29%) were GG. The mean age was 44 years for GG vs. 38 years for CC-CG (p < 0.001). GG was more common in African-American women than white women (69% vs. 13%, p < 0.001) and more commonly estrogen receptor negative (70% vs. 49%, p = 0.02). There were no significant correlations of rs560191 with other critical variables. Despite the fact that GG patients were older, the 10-year rate of local relapses was higher (22% for GG vs. 12% for CC-CG, p = 0.04). Conclusions: This novel avenue of investigation of polymorphisms in radiation repair/response genes in patients treated with BCS + RT suggests a correlation to local relapse. Additional evaluation is needed to assess the biological and functional significance of these single nucleotide polymorphisms, and larger confirmatory validation studies will be required to determine the clinical implications.

  7. Biological significance of the focus on DNA damage checkpoint factors remained after irradiation of ionizing radiation

    This paper reviews recent reports on the focus formation and participation to checkpoint of (such phosphorylated (P-d) as below) ATM and H2AX, MDC1, 53BP1 and NBS1, and discusses their role in DNA damage checkpoint induction mainly around authors' studies. When the cell is irradiated by ionizing radiation, the subtype histone like H2AX is P-d and the formed focus', seen in the nucleus on immuno-fluorographic observation, represents the P-d H2AX at the damaged site of DNA. The role of P-d ATM (the product of causative gene of ataxia-telangiectasia mutation, a protein kinase) has been first shown by laser beam irradiation. Described are discussions on the roles and functions after irradiation in focus formation and DNA damage checkpoint of P-d H2AX (a specific histone product by the radiation like γ-ray as above), P-d ATM, MDC1 (a mediator of DNA damage check point protein 1), 53BP1, (a p53 binding protein) and NBS1 (the product of the causative gene of Nijmegen Breakage Syndrome). Authors have come to point out the remained focal size increase as implications of the efficient repair of damaged DNA, and the second cycled p53 accumulation, of tumor suppression. Thus evaluation of biological significance of these aspects, scarcely noted hitherto, is concluded important. (S.I.)

  8. Precise formation of geometrically focused ion beams

    Geometrically focused intense neutral beams for plasma diagnostic consist of many elementary beams formed by a multiaperture ion-optical system and aimed at the focal point. In real conditions, some of the elementary beams may have increased angular divergence and/or deviate from the intended direction, thus diminishing the neutral beam density at the focus. Several improvements to the geometrical focusing are considered in the article including flattening of the plasma profile across the emission surface, using of quasi-Pierce electrodes at the beam periphery, and minimizing the deviation of the electrodes from the spherical form. Application of these measures to the neutral beam Russian diagnostic injector developed in Budker Institute of Nuclear Physics allows an increase of neutral beam current density in the focus by ∼50%

  9. Focus on the post-DVD formats

    He, Hong; Wei, Jingsong

    2005-09-01

    As the digital TV(DTV) technologies are developing rapidly on its standard system, hardware desktop, software model, and interfaces between DTV and the home net, High Definition TV (HDTV) program worldwide broadcasting is scheduled. Enjoying high quality TV program at home is not a far-off dream for people. As for the main recording media, what would the main stream be for the optical storage technology to meet the HDTV requirements is becoming a great concern. At present, there are a few kinds of Post-DVD formats which are competing on technology, standard and market. Here we give a review on the co-existing Post-DVD formats in the world. We will discuss on the basic parameters for optical disk, video /audio coding strategy and system performance for HDTV program.

  10. A Role for BLM in Double-Strand Break Repair Pathway Choice: Prevention of CtIP/Mre11-Mediated Alternative Nonhomologous End-Joining

    Grabarz, Anastazja; Guirouilh-Barbat, Josée; Barascu, Aurelia; Pennarun, Gaëlle; Genet, Diane; Rass, Emilie; Germann, Susanne Manuela; Bertrand, Pascale; Hickson, Ian David; Lopez, Bernard S.

    2013-01-01

    represses A-EJ in an epistatic manner with 53BP1 and RIF1 and is required for ionizing-radiation-induced 53BP1 focus assembly. Conversely, in the absence of 53BP1 or RIF1, BLM promotes formation of A-EJ long deletions, consistent with a role for BLM in DSB end resection. These data highlight a dual role for...

  11. Food Composition Database Format and Structure: A User Focused Approach

    Annabel K Clancy; Kaitlyn Woods; Anne McMahon; Yasmine Probst

    2015-01-01

    This study aimed to investigate the needs of Australian food composition database user's regarding database format and relate this to the format of databases available globally. Three semi structured synchronous online focus groups (M = 3, F = 11) and n = 6 female key informant interviews were recorded. Beliefs surrounding the use, training, understanding, benefits and limitations of food composition data and databases were explored. Verbatim transcriptions underwent preliminary coding follow...

  12. Food Composition Database Format and Structure: A User Focused Approach

    Clancy, Annabel K.; Woods, Kaitlyn; McMahon, Anne; Probst, Yasmine

    2015-01-01

    This study aimed to investigate the needs of Australian food composition database user’s regarding database format and relate this to the format of databases available globally. Three semi structured synchronous online focus groups (M = 3, F = 11) and n = 6 female key informant interviews were recorded. Beliefs surrounding the use, training, understanding, benefits and limitations of food composition data and databases were explored. Verbatim transcriptions underwent preliminary coding follow...

  13. Optimization of sources for focusing wave energy in targeted formations

    Jeong, C

    2010-06-08

    We discuss a numerical approach for identifying the surface excitation that is necessary to maximize the response of a targeted subsurface formation. The motivation stems from observations in the aftermath of earthquakes, and from limited field experiments, whereby increased oil production rates were recorded and were solely attributable to the induced reservoir shaking. The observations suggest that focusing wave energy to the reservoir could serve as an effective low-cost enhanced oil recovery method. In this paper, we report on a general method that allows the determination of the source excitation, when provided with a desired maximization outcome at the targeted formation. We discuss, for example, how to construct the excitation that will maximize the kinetic energy in the target zone, while keeping silent the neighbouring zones. To this end, we cast the problem as an inverse-source problem, and use a partial-differential- equation-constrained optimization approach to arrive at an optimized source signal. We seek to satisfy stationarity of an augmented functional, which formally leads to a triplet of state, adjoint and control problems. We use finite elements to resolve the state and adjoint problems, and an iterative scheme to satisfy the control problem to converge to the sought source signal. We report on one-dimensional numerical experiments in the time domain involving a layered medium of semi-infinite extent. The numerical results show that the targeted formation\\'s kinetic energy resulting from an optimized wave source could be several times greater than the one resulting from a blind source choice, and could overcome the mobility threshold of entrapped reservoir oil. © 2010 Nanjing Geophysical Research Institute.

  14. Optimization of sources for focusing wave energy in targeted formations

    We discuss a numerical approach for identifying the surface excitation that is necessary to maximize the response of a targeted subsurface formation. The motivation stems from observations in the aftermath of earthquakes, and from limited field experiments, whereby increased oil production rates were recorded and were solely attributable to the induced reservoir shaking. The observations suggest that focusing wave energy to the reservoir could serve as an effective low-cost enhanced oil recovery method. In this paper, we report on a general method that allows the determination of the source excitation, when provided with a desired maximization outcome at the targeted formation. We discuss, for example, how to construct the excitation that will maximize the kinetic energy in the target zone, while keeping silent the neighbouring zones. To this end, we cast the problem as an inverse-source problem, and use a partial-differential-equation-constrained optimization approach to arrive at an optimized source signal. We seek to satisfy stationarity of an augmented functional, which formally leads to a triplet of state, adjoint and control problems. We use finite elements to resolve the state and adjoint problems, and an iterative scheme to satisfy the control problem to converge to the sought source signal. We report on one-dimensional numerical experiments in the time domain involving a layered medium of semi-infinite extent. The numerical results show that the targeted formation's kinetic energy resulting from an optimized wave source could be several times greater than the one resulting from a blind source choice, and could overcome the mobility threshold of entrapped reservoir oil

  15. Double emulsion formation through hierarchical flow-focusing microchannel

    Azarmanesh, Milad; Farhadi, Mousa; Azizian, Pooya

    2016-03-01

    A microfluidic device is presented for creating double emulsions, controlling their sizes and also manipulating encapsulation processes. As a result of three immiscible liquids' interaction using dripping instability, double emulsions can be produced elegantly. Effects of dimensionless numbers are investigated which are Weber number of the inner phase (Wein), Capillary number of the inner droplet (Cain), and Capillary number of the outer droplet (Caout). They affect the formation process, inner and outer droplet size, and separation frequency. Direct numerical simulation of governing equations was done using volume of fluid method and adaptive mesh refinement technique. Two kinds of double emulsion formation, the two-step and the one-step, were simulated in which the thickness of the sheath of double emulsions can be adjusted. Altering each dimensionless number will change detachment location, outer droplet size and droplet formation period. Moreover, the decussate regime of the double-emulsion/empty-droplet is observed in low Wein. This phenomenon can be obtained by adjusting the Wein in which the maximum size of the sheath is discovered. Also, the results show that Cain has significant influence on the outer droplet size in the two-step process, while Caout affects the sheath in the one-step formation considerably.

  16. Problems of the DPF (dense Plasma Focus) current sheath formation

    It is shown by plasma interferometric, magnetic probe, spectroscopic and various anode surface investigation methods, accompanied by the ionizing radiations monitoring, that for the normal functioning of the DPF it is necessary to organize an unimpeded feeding of the ion component within the current sheath (CS) directly from the anode surface, that can be provided by means of the formation on it of the foam film saturated by deuterium. (Author)

  17. Focusing on clay formation as host media of HLW geological disposal in China

    Host medium is vitally important for safety for HLW geological disposal. Chinese HLW disposal effort in the past decades were mainly focused on granite formation. However, the granite formation has fatal disadvantage for HLW geological disposal. This paper reviews experiences gained and lessons learned in the international community and analyzes key factors affecting the site selection. It is recommended that clay formation should be taken into consideration and additional effort should be made before decision making of host media of HLW disposal in China. (authors)

  18. FOCUS ON FORMATIVE FEEDBACKCOMMUNICATION AND SELF-REGULATED LEARNING – A STUDY IN COMPULSORY SCHOOLS

    Kirkegaard, Preben Olund

    2016-01-01

    This study addresses the conceptual challenge of providing students in compulsory schools with good quality formative feedback to enhance self-regulated learning in social interactions. Resent educational research indicates that social communicative interactions in the classroom, with a focus on...... formative feedback, hold the potential to enhance students learning. Self-regulated learning is highly pertinent and can be seen as one of the most import skills for the 21st century learner. We argue that formative feedbackcommunication in interactions is crucial for students to develop self......-regulating skills and that feedback is not only something the teacher gives to the student. We refer to this as formative Feedbackcommunication. As a basis for exploring identifying and discussing relevant aspects of formative Feedbackcommunication to enhance student self-regulating learning skills we analyze...

  19. Identity Formation in Educational Settings: A Critical Focus for Education in the 21st Century

    Kaplan, Avi; Flum, Hanoch

    2012-01-01

    There is growing recognition that identity formation must become an important focus in education. Particularly in the 21st century, when modes of knowledge construction and accessibility to different types of knowledge are rapidly increasing and diversifying, academic learning cannot be divorced from students' development of values, goals, social…

  20. Formation of brand-focused communication management system of industrial enterprise

    Ivashova Nadiia Vasylivna

    2014-12-01

    Full Text Available The aim of the article. The importance of communication in formation brand industrial enterprise is defined in the article. The essence of the concept of “brand-focused communications management system” and the purpose of such an approach to the management of marketing communications company are investigated. The mechanism of brand-focused communications management system is proposed and it is explored its components. Peculiarities management functions arising from the implementation of an industrial enterprise brand-oriented management communications system are analyzed. The results of the analysis. The research highlights the importance of communication in the formation of industrial enterprise brand. The model of the brand is depicted through the use of enterprise-oriented brand communications. The mechanism of brand-focused communications management is suggested and investigation its components is realized. Specific of the proposed brand-focused communications management system of industrial enterprise are: harmonization objectives and brand communications within target subsystem; integration of principles and criteria brand-focused management into management subsystem, allocation role of corporate culture for brand-focused communication management. Conclusions and directions of further researches. Thus, peculiarities of management functions arising from the implementation of an industrial enterprise brand-focused management communications are investigated. Future research requires additional research defining of principles of brand-focused communications management of enterprise that will ensure such impact communications when each type of marketing communication strengthens the position of the brand in the consumer perception and enforce complementing, enhancing and refining an idea of the brand that is already formed. Another important area for future research is the development of an appropriate organizational structure that would

  1. Trust, responsibility, and freedom: Focus-group research on contemporary patterns of union formation in Russia

    Olga Isupova

    2015-01-01

    Background: While some studies directly address the issue of changes in union formation in Russia and Eastern Europe, few have focused on attitudes and norms regarding marriage and cohabitation. In Russia cohabitation has risen sharply in the last decades, but recently its level has stabilized and even decreased slightly. Objective: We intend to highlight gender and educational differences in perceptions of the advantages and disadvantages of cohabitation vs. marriage. Methods: We condu...

  2. Effect of a focusing electric field on the formation of arc generated carbon nanotubes

    Karmakar, Soumen; Nagar, Harshada; Pasricha, R.; Seth, T.; Sathe, V. G.; Bhoraskar, S. V.; Das, A. K.

    2006-12-01

    The effect of a focusing electric field on the formation of carbon nanotubes in a direct current arc-plasma is investigated. The hard deposits on the surface of the cathode are the main products, rich in multi-walled carbon nanotubes. It is seen that the focusing electric field has a distinct influence on the yield, purity and morphology of the nanotubes. The yield of the carbon nanotubes under the 'focused field condition' has been found to be higher than that derived from the normal electrode configuration. It has been observed that the deposition of carbonaceous soot on the reactor wall is considerably reduced on application of the focusing electric field. Transmission electron microscopy has been used to determine the morphology of the nanotubes. In addition, Raman spectroscopy has helped in distinguishing the graphene-like structures from the disordered carbon networks and helped in analysing the morphology of the tubes. Thermal analysis gave a qualitative estimation of the relative yield of carbon nanotubes within the cathode deposits and their thermal stabilities. The crystalline nature of the samples has been confirmed by x-ray diffraction analysis. The results clearly indicate that the focusing electric field confines the positively charged carbon precursors within the cathode-anode space causing high relative yield and purity and has a distinct effect on controlling the inner diameter of the as-synthesized carbon nanotubes.

  3. Wave energy focusing to subsurface poroelastic formations to promote oil mobilization

    Karve, P. M.

    2015-04-22

    We discuss an inverse source formulation aimed at focusing wave energy produced by ground surface sources to target subsurface poroelastic formations. The intent of the focusing is to facilitate or enhance the mobility of oil entrapped within the target formation. The underlying forward wave propagation problem is cast in two spatial dimensions for a heterogeneous poroelastic target embedded within a heterogeneous elastic semi-infinite host. The semi-infiniteness of the elastic host is simulated by augmenting the (finite) computational domain with a buffer of perfectly matched layers. The inverse source algorithm is based on a systematic framework of partial-differential-equation-constrained optimization. It is demonstrated, via numerical experiments, that the algorithm is capable of converging to the spatial and temporal characteristics of surface loads that maximize energy delivery to the target formation. Consequently, the methodology is well-suited for designing field implementations that could meet a desired oil mobility threshold. Even though the methodology, and the results presented herein are in two dimensions, extensions to three dimensions are straightforward.

  4. Nanohole pattern formation on Ge by focused ion beam and broad beam

    The morphology of surfaces strongly influences optical, electrical, and magnetic properties of thin films. Using low energy ion beam sputtering different self-organized periodic patterns can be obtained. These are ripple patterns with periodicities in the nanometre range for oblique ion incidence and hexagonal dot patterns on compound materials for normal incidence. Low energy ion beam sputtering of Ge at normal incidence using a 5 keV Ga+ focused ion beam (FIB) produces periodic nanohole patterns. In this work we studied the flux dependence of nanohole formation using FIB technique and compared the results with patterns produced by broad Ga+ beam sputtering with a six orders of magnitude smaller ion flux. In both cases Ga+ ions with an energy of 5 keV at normal incidence were used. Obtaining the same results shows that nanohole formation is independent of flux over a few orders of magnitude and that rastering of the FIB does not add extra contributions.

  5. Capillary isoelectric focusing--useful tool for detection of the biofilm formation in Staphylococcus epidermidis.

    Ruzicka, Filip; Horka, Marie; Hola, Veronika; Votava, Miroslav

    2007-03-01

    The biofilm formation is an important factor of S. epidermidis virulence. Biofilm-positive strains might be clinically more important than biofilm-negative ones. Unlike biofilm-negative staphylococci, biofilm-positive staphylococci are surrounded with an extracellular polysaccharide substance. The presence of this substance on the surface can affect physico-chemical properties of the bacterial cell, including surface charge. 73 S. epidermidis strains were examined for the presence of ica operon, for the ability to form biofilm by Christensen test tube method and for the production of slime by Congo red agar method. Isoelectric points (pI) of these strains were determined by means of Capillary Isoelectric Focusing. The biofilm negative strains focused near pI value 2.3, while the pI values of the biofilm positive strains were near 2.6. Isoelectric point is a useful criterion for the differentiation between biofilm-positive and biofilm-negative S. epidermidis strains. PMID:17157942

  6. Formation of plasma channels in air under filamentation of focused ultrashort laser pulses

    Ionin, A. A.; Seleznev, L. V.; Sunchugasheva, E. S.

    2015-03-01

    The formation of plasma channels in air under filamentation of focused ultrashort laser pulses was experimentally and theoretically studied together with theoreticians of the Moscow State University and the Institute of Atmospheric Optics. The influence of various characteristics of ultrashort laser pulses on these plasma channels is discussed. Plasma channels formed under filamentation of focused laser beams with a wavefront distorted by spherical aberration (introduced by adaptive optics) and by astigmatism, with cross-section spatially formed by various diaphragms and with different UV and IR wavelengths, were experimentally and numerically studied. The influence of plasma channels created by a filament of a focused UV or IR femtosecond laser pulse (λ = 248 nm or 740 nm) on characteristics of other plasma channels formed by a femtosecond pulse at the same wavelength following the first one with varied nanosecond time delay was also experimentally studied. An application of plasma channels formed due to the filamentation of focused UV ultrashort laser pulses including a train of such pulses and a combination of ultrashort and long (~100 ns) laser pulses for triggering and guiding long (~1 m) electric discharges is discussed.

  7. Fluid displacement during droplet formation at microfluidic flow-focusing junctions.

    Huang, Haishui; He, Xiaoming

    2015-11-01

    Microdroplets and microcapsules have been widely produced using microfluidic flow-focusing junctions for biomedical and chemical applications. However, the multiphase microfluidic flow at the flow-focusing junction has not been well investigated. In this study, the displacement of two (core and shell) aqueous fluids that disperse into droplets altogether in a carrier oil emulsion was investigated both numerically and experimentally. It was found that extensive displacement of the two aqueous fluids within the droplet during its formation could occur as a result of the shear effect of the carrier fluid and the capillary effect of interfacial tension. We further identified that the two mechanisms of fluid displacement can be evaluated by two dimensionless parameters. The quantitative relationship between the degree of fluid displacement and these two dimensionless parameters was determined experimentally. Finally, we demonstrated that the degree of fluid displacement could be controlled to generate hydrogel microparticles of different morphologies using planar or nonplanar flow-focusing junctions. These findings should provide useful guidance to the microfluidic production of microscale droplets or capsules for various biomedical and chemical applications. PMID:26381220

  8. Electromagnetic particle in cell modeling of the plasma focus: Current sheath formation and lift off

    The shaping and formation of the current sheath takes place in the breakdown phase of a plasma focus device and critically controls the device performance. Electrostatic particle in cell codes, with magnetic effects ignored, have been used to model the breakdown phase. This Letter reports the successful development and implementation of an electromagnetic particle in cell (EMPIC) code, including magnetic effects self-consistently, to simulate the breakdown phase; from the ionization, localization and gliding discharge along the insulator to the time instant of current sheath lift off. The magnetic field was found to be appreciable from the time the current sheath came into contact with the anode with increased local current, initiating the voltage breakdown of the device as a result

  9. Membrane Thickness Dependence of Nanopore Formation with a Focused Helium Ion Beam

    Furat Sawafta

    2014-05-01

    Full Text Available Solid-state nanopores are emerging as a valuable tool for the detection and characterization of individual biomolecules. Central to their success is the realization of fabrication strategies that are both rapid and flexible in their ability to achieve diverse device dimensions. In this paper, we demonstrate the membrane thickness dependence of solid-state nanopore formation with a focused helium ion beam. We vary membrane thickness in situ and show that the rate of pore expansion follows a reproducible trend under all investigated membrane conditions. We show that this trend shifts to lower ion dose for thin membranes in a manner that can be described quantitatively, allowing devices of arbitrary dimension to be realized. Finally, we demonstrate that thin, small-diameter nanopores formed with our approach can be utilized for high signal-to-noise ratio resistive pulse sensing of DNA.

  10. Hybrid Detectors Improved Time-Lapse Confocal Microscopy of PML and 53BP1 Nuclear Body Colocalization in DNA Lesions

    Foltánková, Veronika; Matula, Pa.; Sorokin, D.; Kozubek, Stanislav; Bártová, Eva

    2013-01-01

    Roč. 19, č. 2 (2013), s. 360-369. ISSN 1431-9276 R&D Projects: GA ČR(CZ) GBP302/12/G157 Institutional research plan: CEZ:AV0Z50040702 Institutional support: RVO:68081707 Keywords : CLASS-SWITCH RECOMBINATION * DAMAGE-RESPONSE * HOMOLOGOUS RECOMBINATION Subject RIV: BO - Biophysics Impact factor: 1.757, year: 2013

  11. The mechanism of lesion formation by focused ultrasound ablation catheter for treatment of atrial fibrillation

    Sinelnikov, Y. D.; Fjield, T.; Sapozhnikov, O. A.

    2009-10-01

    The application of therapeutic ultrasound for the treatment of atrial fibrillation (AF) is investigated. The results of theoretical and experimental investigation of ultrasound ablation catheter are presented. The major components of the catheter are the high power cylindrical piezoelectric element and parabolic balloon reflector. Thermal elevation in the ostia of pulmonary veins is achieved by focusing the ultrasound beam in shape of a torus that transverses the myocardial tissue. High intensity ultrasound heating in the focal zone results in a lesion surrounding the pulmonary veins that creates an electrical conduction blocks and relief from AF symptoms. The success of the ablation procedure largely depends on the correct choice of reflector geometry and ultrasonic power. We present a theoretical model of the catheter’s acoustic field and bioheat transfer modeling of cardiac lesions. The application of an empirically derived relation between lesion formation and acoustic power is shown to correlate with the experimental data. Developed control methods combine the knowledge of theoretical acoustics and the thermal lesion formation simulations with experiment and thereby establish dosimetry that contributes to a safe and effective ultrasound ablation procedure.

  12. Mechanisms of material removal and mass transport in focused ion beam nanopore formation

    Das, Kallol, E-mail: das7@illinois.edu; Johnson, Harley T., E-mail: htj@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, MC-244, Urbana, Illinois 61801 (United States); Freund, Jonathan B., E-mail: jbfreund@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, MC-244, Urbana, Illinois 61801 (United States); Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, 306 Talbot Laboratory, MC-236, 104 South Wright Street Urbana, Illinois 61801 (United States)

    2015-02-28

    Despite the widespread use of focused ion beam (FIB) processing as a material removal method for applications ranging from electron microscope sample preparation to nanopore processing for DNA sequencing, the basic material removal mechanisms of FIB processing are not well understood. We present the first complete atomistic simulation of high-flux FIB using large-scale parallel molecular dynamics (MD) simulations of nanopore fabrication in freestanding thin films. We focus on the root mechanisms of material removal and rearrangement and describe the role of explosive boiling in forming nanopores. FIB nanopore fabrication is typically understood to occur via sputter erosion. This can be shown to be the case in low flux systems, where individual ion impacts are sufficiently separated in time that they may be considered as independent events. But our detailed MD simulations show that in high flux FIB processing, above a threshold level at which thermal effects become significant, the primary mechanism of material removal changes to a significantly accelerated, thermally dominated process. Under these conditions, the target is heated by the ion beam faster than heat is conducted away by the material, leading quickly to melting, and then continued heating to nearly the material critical temperature. This leads to explosive boiling of the target material with spontaneous bubble formation and coalescence. Mass is rapidly rearranged at the atomistic scale, and material removal occurs orders of magnitude faster than would occur by simple sputtering. While the phenomenology is demonstrated computationally in silicon, it can be expected to occur at lower beam fluxes in other cases where thermal conduction is suppressed due to material properties, geometry, or ambient thermal conditions.

  13. DNA damage focus analysis in blood samples of minipigs reveals acute partial body irradiation.

    Andreas Lamkowski

    Full Text Available Radiation accidents frequently involve acute high dose partial body irradiation leading to victims with radiation sickness and cutaneous radiation syndrome that implements radiation-induced cell death. Cells that are not lethally hit seek to repair ionizing radiation (IR induced damage, albeit at the expense of an increased risk of mutation and tumor formation due to misrepair of IR-induced DNA double strand breaks (DSBs. The response to DNA damage includes phosphorylation of histone H2AX in the vicinity of DSBs, creating foci in the nucleus whose enumeration can serve as a radiation biodosimeter. Here, we investigated γH2AX and DNA repair foci in peripheral blood lymphocytes of Göttingen minipigs that experienced acute partial body irradiation (PBI with 49 Gy (± 6% Co-60 γ-rays of the upper lumbar region. Blood samples taken 4, 24 and 168 hours post PBI were subjected to γ-H2AX, 53BP1 and MRE11 focus enumeration. Peripheral blood lymphocytes (PBL of 49 Gy partial body irradiated minipigs were found to display 1-8 DNA damage foci/cell. These PBL values significantly deceed the high foci numbers observed in keratinocyte nuclei of the directly γ-irradiated minipig skin regions, indicating a limited resident time of PBL in the exposed tissue volume. Nonetheless, PBL samples obtained 4 h post IR in average contained 2.2% of cells displaying a pan-γH2AX signal, suggesting that these received a higher IR dose. Moreover, dispersion analysis indicated partial body irradiation for all 13 minipigs at 4 h post IR. While dose reconstruction using γH2AX DNA repair foci in lymphocytes after in vivo PBI represents a challenge, the DNA damage focus assay may serve as a rapid, first line indicator of radiation exposure. The occurrence of PBLs with pan-γH2AX staining and of cells with relatively high foci numbers that skew a Poisson distribution may be taken as indicator of acute high dose partial body irradiation, particularly when samples are available

  14. Impact of preconditioning pulse on lesion formation during high-intensity focused ultrasound histotripsy.

    Xu, Jin; Bigelow, Timothy A; Riesberg, Grant M

    2012-11-01

    Therapeutic applications with high-intensity focused ultrasound (HIFU) fall into two classifications-one using thermal effect for coagulation or ablation while generally avoiding cavitation and the other using cavitation-mediated mechanical effects while suppressing heating. Representative of the latter, histotripsy uses HIFU at low duty factor to create energetic bubble clouds inside tissue to liquefy a region and has the advantages in real-time monitoring and lesion fidelity to treatment planning. We explored the impact of a preconditioning/heating pulse on histotripsy lesion formation in porcine muscle samples. During sonication, a targeted square region 9 mm wide (lateral to the focal plane) was scanned in a raster pattern with a step size of 0.75 mm. The 20-s exposure at each treatment location consisted of a 5-s duration preconditioning burst at spatial-peak intensities from 0-1386 W/cm² followed by 5000 tone bursts at high intensity (with spatial-peak pulse-average intensity of 47.34 kW/cm², spatial-peak temporal-average intensity of 284 W/cm², peak compressional pressure of 102 MPa and peak rarefactional pressure of 17 MPa). The temperature increase for all exposures was measured using a thermal imager immediately after each exposure. Lesion volume increased with increasing amplitude of the preconditioning pulse until coagulation was observed, but lesion width/area did not change significantly with the amplitude. In addition, the lesion dimensions became smaller when the global tissue temperature was raised before applying the histotripsy pulsing sequence. Therefore, the benefit of the preconditioning pulse was not caused by global heating. PMID:22929656

  15. Neocarzinostatin-induced Rad51 nuclear focus formation is cell cycle regulated and aberrant in AT cells

    DNA double-stranded breaks are the most detrimental form of DNA damage and, if not repaired properly, may lead to an accumulation of chromosomal aberrations and eventually tumorigenesis. Proteins of the Rad51/Rad52 epitasis group are crucial for the recombinational repair of DNA double-stranded breaks, whereas the Rad50/NBS1/Mre11 nuclease complex is involved in both the recombinational and the end-joining repair of DNA double-stranded breaks. Herein, we demonstrate that the chemotherapeutic enediyne antibiotic neocarzinostatin induced Rad51, but not NBS1, nuclear focus formation in a cell- cycle-dependent manner. Furthermore, neocarzinostatin-induced Rad51 foci formation revealed a slower kinetic change in AT cells, but not in wild-type or NBS cells. In summary, our results suggest that neocarzinostatin induces Rad51 focus formation through an ATM- and cell-cycle-dependent, but NBS1-independent, pathway

  16. Reporting Format for Economic Evaluation: Part II: Focus on Modelling Studies

    Nuijten, C.; Pronk, Marja H; Mark J. A. Brorens; Hekster, Yechiel A; Jacques H. M. Lockefeer; De Smet, Peter A G M; Gouke Bonsel; Ary Van der Kuy

    1998-01-01

    This article presents the first version of a reporting format for modelling studies which is based on a general reporting format by our taskforce, which was published in the previous issue of this journal. The use of decision-analytical models for economic evaluations is increasing because, in practice, it is not always possible to derive information from prospective studies. However, the acceptance of modelling studies is generally lower than prospective studies not only because of the use o...

  17. Patterned Formation of Highly Coherent Nitrogen-Vacancy Centers Using a Focused Electron Irradiation Technique.

    McLellan, Claire A; Myers, Bryan A; Kraemer, Stephan; Ohno, Kenichi; Awschalom, David D; Bleszynski Jayich, Ania C

    2016-04-13

    We demonstrate fully three-dimensional and patterned localization of nitrogen-vacancy (NV) centers in diamond with coherence times in excess of 1 ms. Nitrogen δ-doping during chemical vapor deposition diamond growth vertically confines nitrogen to 4 nm while electron irradiation with a transmission electron microscope laterally confines vacancies to less than 450 nm. We characterize the effects of electron energy and dose on NV formation. Importantly, our technique enables the formation of reliably high-quality NV centers inside diamond nanostructures with applications in quantum information and sensing. PMID:27010642

  18. Molecular dynamics simulation of ion focusing and crowdion formation in self-ion-irradiated Fe

    Chen Di [Department of Nuclear Engineering, Texas A and M University, College Station, Texas 77843 (United States); Shao Lin, E-mail: lshao@mailaps.org [Department of Nuclear Engineering, Texas A and M University, College Station, Texas 77843 (United States)

    2012-02-01

    We have used molecular dynamics (MD) simulation to investigate damage and defect development in a Left-Pointing-Angle-Bracket 1 0 0 Right-Pointing-Angle-Bracket Fe substrate upon 2 keV Fe ion bombardment. The damage cascade formation is accompanied by atomic shifting over a limited distance along the direction of one atomic row, which leads to formation of crowdions aligned with Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket direction. At the end of structural relaxation and defect recombination, crowdions lead to formation of dumbbell defects - a type of vacancy-interstitial complexes having one vacancy between a pair of slightly displaced interstitials. The dumbbell defects are initially oriented along Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket direction. After a typical period of 0.2 ps, some dumbbell defects rotate towards Left-Pointing-Angle-Bracket 1 1 0 Right-Pointing-Angle-Bracket direction. Crowdion and dumbbell defect formation influence the time dependent damage buildups.

  19. Bubble formation in yield stress fluids using flow-focusing and T-Junction devices

    Laborie, Benoît; Rouyer, Florence; Angelescu, Dan,; Lorenceau, Elise

    2015-01-01

    We study the production of bubbles inside yield stress fluids (YSFs) in axisymmetric T-junction and flow-focusing devices. Taking advantage of yield stress over capillary stress, we exhibit a robust break-up mechanism reminiscent of the geometrical operating regime in 2D flow-focusing devices for Newtonian fluids. We report that when the gas is pressure driven, the dynamics is unsteady due to hydrodynamic feedback and YSF deposition on the walls of the channels. However, the present study als...

  20. Bubble Formation in Yield Stress Fluids Using Flow-Focusing and T-Junction Devices

    Laborie, Benoît; Rouyer, Florence; Angelescu, Dan,; Lorenceau, Elise

    2015-01-01

    We study the production of bubbles inside yield stress fluids (YSFs) in axisymmetric T-junction and flow-focusing devices. Taking advantage of yield stress over capillary stress, we exhibit a robust break-up mechanism reminiscent of the geometrical operating regime in 2D flow-focusing devices for Newtonian fluids. We report that when the gas is pressure driven, the dynamics is unsteady due to hydrodynamic feedback and YSF deposition on the walls of the channels. However, the present study als...

  1. Development of multilayer Fresnel lens (zone plate) for formation of focused neutron beam

    A fabrication technique of a multilayer optics for the neutron beamline has been shown. The optics is a Fresnel zone plate (FZP) which is used to guide neutron beams to a pinhole in order to use the beam effectively. The design parameter of the FZP as a focusing optics has also been designed. (author)

  2. Surface morphological evolution and nanoneedle formation of 18Cr-ODS steel by focused ion beam bombardment

    Highlights: • Morphological evolution of the 18Cr-ODS was studied under intense ion radiation. • The initial surface morphology of the steel significantly affects the nanoneedle formation, and the microstructure of the nanoneedle was characterized by TEM. • The formation mechanism of nano-needle structure of the 18Cr-ODS was discussed. • Surface defects enhance kinetics of surface roughening and pattern formation. - Abstract: Morphological evolution upon intense energetic particle–matter interactions is of fundamental importance for materials utilized in extreme radiation environment, and controlling surface morphology by radiation also provides a new pathway for exploring non-equilibrium process at surface. In this work, surface morphology and microstructural evolution upon low energy ion irradiation of 18Cr-ODS, a candidate structural material for cladding and first wall of future fission and fusion reactors, were investigated by in situ focused Ga+ ion beam/scanning electron microscopy and ex situ transmission electron microscopy. A surface roughening through pore formation, coalescence and eventually nanoneedle formation was induced on 18Cr-ODS steel surface. Cross-section microstructure analysis indicates that the formation of nanoneedle was not a result of grain recrystallization or chemical composition change. Pre-irradiated materials by He+ and Fe+ ions displays enhanced kinetics for surface morphological evolution and lower fluences of focused Ga+ are required for the nanoneedle formation. These results suggest that the surface roughening and morphological evolution of 18Cr-ODS under low energy ion irradiation is an interplay between a curvature-dependent sputtering and defect accumulation near the surface

  3. Calibration of the γ-H2AX DNA double strand break focus assay for internal radiation exposure of blood lymphocytes.

    Eberlein, Uta; Peper, Michel; Fernández, Maria; Lassmann, Michael; Scherthan, Harry

    2015-01-01

    DNA double strand break (DSB) formation induced by ionizing radiation exposure is indicated by the DSB biomarkers γ-H2AX and 53BP1. Knowledge about DSB foci formation in-vitro after internal irradiation of whole blood samples with radionuclides in solution will help us to gain detailed insights about dose-response relationships in patients after molecular radiotherapy (MRT). Therefore, we studied the induction of radiation-induced co-localizing γ-H2AX and 53BP1 foci as surrogate markers for DSBs in-vitro, and correlated the obtained foci per cell values with the in-vitro absorbed doses to the blood for the two most frequently used radionuclides in MRT (I-131 and Lu-177). This approach led to an in-vitro calibration curve. Overall, 55 blood samples of three healthy volunteers were analyzed. For each experiment several vials containing a mixture of whole blood and radioactive solutions with different concentrations of isotonic NaCl-diluted radionuclides with known activities were prepared. Leukocytes were recovered by density centrifugation after incubation and constant blending for 1 h at 37°C. After ethanol fixation they were subjected to two-color immunofluorescence staining and the average frequencies of the co-localizing γ-H2AX and 53BP1 foci/nucleus were determined using a fluorescence microscope equipped with a red/green double band pass filter. The exact activity was determined in parallel in each blood sample by calibrated germanium detector measurements. The absorbed dose rates to the blood per nuclear disintegrations occurring in 1 ml of blood were calculated for both isotopes by a Monte Carlo simulation. The measured blood doses in our samples ranged from 6 to 95 mGy. A linear relationship was found between the number of DSB-marking foci/nucleus and the absorbed dose to the blood for both radionuclides studied. There were only minor nuclide-specific intra- and inter-subject deviations. PMID:25853575

  4. Calibration of the γ-H2AX DNA double strand break focus assay for internal radiation exposure of blood lymphocytes.

    Uta Eberlein

    Full Text Available DNA double strand break (DSB formation induced by ionizing radiation exposure is indicated by the DSB biomarkers γ-H2AX and 53BP1. Knowledge about DSB foci formation in-vitro after internal irradiation of whole blood samples with radionuclides in solution will help us to gain detailed insights about dose-response relationships in patients after molecular radiotherapy (MRT. Therefore, we studied the induction of radiation-induced co-localizing γ-H2AX and 53BP1 foci as surrogate markers for DSBs in-vitro, and correlated the obtained foci per cell values with the in-vitro absorbed doses to the blood for the two most frequently used radionuclides in MRT (I-131 and Lu-177. This approach led to an in-vitro calibration curve. Overall, 55 blood samples of three healthy volunteers were analyzed. For each experiment several vials containing a mixture of whole blood and radioactive solutions with different concentrations of isotonic NaCl-diluted radionuclides with known activities were prepared. Leukocytes were recovered by density centrifugation after incubation and constant blending for 1 h at 37°C. After ethanol fixation they were subjected to two-color immunofluorescence staining and the average frequencies of the co-localizing γ-H2AX and 53BP1 foci/nucleus were determined using a fluorescence microscope equipped with a red/green double band pass filter. The exact activity was determined in parallel in each blood sample by calibrated germanium detector measurements. The absorbed dose rates to the blood per nuclear disintegrations occurring in 1 ml of blood were calculated for both isotopes by a Monte Carlo simulation. The measured blood doses in our samples ranged from 6 to 95 mGy. A linear relationship was found between the number of DSB-marking foci/nucleus and the absorbed dose to the blood for both radionuclides studied. There were only minor nuclide-specific intra- and inter-subject deviations.

  5. In vitro formation of a secondary epileptogenic mirror focus by interhippocampal propagation of seizures.

    Khalilov, Ilgam; Holmes, Gregory,; Ben-Ari, Yehezkel

    2003-01-01

    International audience We have determined whether seizures generate an epileptogenic focus in distal structures using an in vitro preparation composed of three independent chambers that accommodate two intact hippocampi and their connecting commissures. This enabled us to apply a convulsive agent to one hippocampus, allow the propagation of a given number of seizures to the other side and block the connections reversibly by applying tetrodotoxin (TTX) to the commissural chamber. The propag...

  6. Optical contrast formation in amorphous silicon carbide with high-energy focused ion beams

    Thin films (d ∼ 1 μm) of hydrogenated amorphous silicon carbide (a-Si1-xCx:H), deposited by RF reactive magnetron sputtering with different carbon content x, have been implanted with high fluences (Φ = 1016-1017 cm-2) of high-energy (E = 0.2-1 MeV) He+ ions as the implant species. The induced structural modification of the implanted material results in a considerable change of its optical properties, best manifested by a significant shift of the optical absorption edge to lower photon energies as obtained from photo-thermal-deflection spectroscopy (PDS) data. This shift is accompanied by a remarkable increase of the absorption coefficient over one order of magnitude (photo-darkening effect) in the measured photon energy range (0.6-3.8 eV), depending on the ion fluence, energy and carbon content of the films. These effects could be attributed both to additional defect introduction and increased graphitization, as confirmed by Raman spectroscopy and infra-red (IR) optical transmission measurements. The optical contrast thus obtained (between implanted and unimplanted film material) could be made use of in the area of high-density optical data storage using focused high-energy He+ ion beams.

  7. Time-resolved mixing and flow-field measurements during droplet formation in a flow-focusing junction

    Carrier, Odile; Gökhan Ergin, F.; Li, Huai-Zhi; Watz, Bo B.; Funfschilling, Denis

    2015-08-01

    Highly monodispersed emulsions can be produced in microfluidic flow-focusing junctions (Anna et al 2003 Appl. Phys. Lett. 82 364-6, Baroud et al 2010 Lab Chip 10 2032-45). This is the reason why many industrial processes in the medical industry among others are based on droplet manipulation and involve at some point a step of dripping within a junction. However, only a few studies have focused on the flow field inside and outside the droplet, even though it is a necessary step for understanding the physical mechanism involved and for modeling the droplet formation process. Water-in-oil emulsions are produced in flow-focusing junctions of square cross sections. The fluids constituting the emulsion are (i) a 5.0 mPa·s silicon oil for the oil phase and (ii) distilled water containing 2.0 wt% of sodium dodecyl sulfate surfactant for the aqueous phase. Time-resolved shadow particle images are acquired using a microscale particle image velocimetry (µPIV) system and flow fields are calculated using an adaptive PIV algorithm in combination with dynamic masking. Inside the microchannel and in the permanent regime, the droplet has an internal circulation that has been well established by Sarrazin et al (AICHE J. 52 4061-70). But during the formation of a droplet in a flow-focusing junction, the flow field is not so well known, and the circulation in the finger flows forward along the sides and returns along the center. The mechanism can be described in terms of four distinct steps: droplet growth, necking, rupture, and recoil. The liquid expelled from the neck just before rupture is also well observed. The flow field and mixing are measured in detail during a complete cycle of formation of a main droplet and satellite droplets using high-speed imaging. This allows us to develop a better understanding of the different forces that are present and of the physical mechanism of droplet formation.

  8. Characterization of lesion formation and bubble activities during high-intensity focused ultrasound ablation using temperature-derived parameters

    Hsiao, Yi-Sing; Kumon, Ronald E.; Deng, Cheri X.

    2013-09-01

    Successful high-intensity focused ultrasound (HIFU) thermal tissue ablation relies on accurate information of the tissue temperature and tissue status. Often temperature measurements are used to predict and monitor the ablation process. In this study, we conducted HIFU ablation experiments with ex vivo porcine myocardium tissue specimens to identify changes in temperature associated with tissue coagulation and bubble/cavity formation. Using infrared (IR) thermography and synchronized bright-field imaging with HIFU applied near the tissue surface, parameters derived from the spatiotemporal evolution of temperature were correlated with HIFU-induced lesion formation and overheating, of which the latter typically results in cavity generation and/or tissue dehydration. Emissivity of porcine myocardium was first measured to be 0.857 ± 0.006 (n = 3). HIFU outcomes were classified into non-ablative, normal lesion, and overheated lesion. A marked increase in the rate of temperature change during HIFU application was observed with lesion formation. A criterion using the maximum normalized second time derivative of temperature change provided 99.1% accuracy for lesion identification with a 0.05 s-1 threshold. Asymmetric temperature distribution on the tissue surface was observed to correlate with overheating and/or bubble generation. A criterion using the maximum displacement of the spatial location of the peak temperature provided 90.9% accuracy to identify overheated lesion with a 0.16 mm threshold. Spatiotemporal evolution of temperature obtained using IR imaging allowed determination of the critical cumulative equivalent minutes at 43 °C (CEM43) for lesion formation to be 170 min. Similar temperature characteristics indicative of lesion formation and overheating were identified for subsurface HIFU ablation. These results suggest that parameters derived from temperature changes during HIFU application are associated with irreversible changes in tissue and may provide

  9. COX-2 inhibition is neither necessary nor sufficient for celecoxib to suppress tumor cell proliferation and focus formation in vitro

    Petasis Nicos A

    2008-05-01

    Full Text Available Abstract Background An increasing number of reports is challenging the notion that the antitumor potential of the selective COX-2 inhibitor celecoxib (Celebrex® is mediated primarily via the inhibition of COX-2. We have investigated this issue by applying two different analogs of celecoxib that differentially display COX-2-inhibitory activity: the first analog, called unmethylated celecoxib (UMC, inhibits COX-2 slightly more potently than its parental compound, whereas the second analog, 2,5-dimethyl-celecoxib (DMC, has lost the ability to inhibit COX-2. Results With the use of glioblastoma and pancreatic carcinoma cell lines, we comparatively analyzed the effects of celecoxib, UMC, and DMC in various short-term (≤48 hours cellular and molecular studies, as well as in long-term (≤3 months focus formation assays. We found that DMC exhibited the most potent antitumor activity; celecoxib was somewhat less effective, and UMC clearly displayed the overall weakest antitumor potential in all aspects. The differential growth-inhibitory and apoptosis-stimulatory potency of these compounds in short-term assays did not at all correlate with their capacity to inhibit COX-2, but was closely aligned with their ability to trigger endoplasmic reticulum stress (ERS, as indicated by the induction of the ERS marker CHOP/GADD153 and activation of the ERS-associated caspase 7. In addition, we found that these compounds were able to restore contact inhibition and block focus formation during long-term, chronic drug exposure of tumor cells, and this was achieved at sub-toxic concentrations in the absence of ERS or inhibition of COX-2. Conclusion The antitumor activity of celecoxib in vitro did not involve the inhibition of COX-2. Rather, the drug's ability to trigger ERS, a known effector of cell death, might provide an alternative explanation for its acute cytotoxicity. In addition, the newly discovered ability of this drug to restore contact inhibition and

  10. Radio Frequency Ultrasound Time Series Signal Analysis to Evaluate High-intensity Focused Ultrasound Lesion Formation Status in Tissue.

    Mobasheri, Saeedeh; Behnam, Hamid; Rangraz, Parisa; Tavakkoli, Jahan

    2016-01-01

    High-intensity focused ultrasound (HIFU) is a novel treatment modality used by scientists and clinicians in the recent decades. This modality has had a great and significant success as a noninvasive surgery technique applicable in tissue ablation therapy and cancer treatment. In this study, radio frequency (RF) ultrasound signals were acquired and registered in three stages of before, during, and after HIFU exposures. Different features of RF time series signals including the sum of amplitude spectrum in the four quarters of the frequency range, the slope, and intercept of the best-fit line to the entire power spectrum and the Shannon entropy were utilized to distinguish between the HIFU-induced thermal lesion and the normal tissue. We also examined the RF data, frame by frame to identify exposure effects on the formation and characteristics of a HIFU thermal lesion at different time steps throughout the treatment. The results obtained showed that the spectrum frequency quarters and the slope and intercept of the best fit line to the entire power spectrum both increased two times during the HIFU exposures. The Shannon entropy, however, decreased after the exposures. In conclusion, different characteristics of RF time series signal possess promising features that can be used to characterize ablated and nonablated tissues and to distinguish them from each other in a quasi-quantitative fashion. PMID:27186536

  11. Radio Frequency Ultrasound Time Series Signal Analysis to Evaluate High-intensity Focused Ultrasound Lesion Formation Status in Tissue

    Mobasheri, Saeedeh; Behnam, Hamid; Rangraz, Parisa; Tavakkoli, Jahan

    2016-01-01

    High-intensity focused ultrasound (HIFU) is a novel treatment modality used by scientists and clinicians in the recent decades. This modality has had a great and significant success as a noninvasive surgery technique applicable in tissue ablation therapy and cancer treatment. In this study, radio frequency (RF) ultrasound signals were acquired and registered in three stages of before, during, and after HIFU exposures. Different features of RF time series signals including the sum of amplitude spectrum in the four quarters of the frequency range, the slope, and intercept of the best-fit line to the entire power spectrum and the Shannon entropy were utilized to distinguish between the HIFU-induced thermal lesion and the normal tissue. We also examined the RF data, frame by frame to identify exposure effects on the formation and characteristics of a HIFU thermal lesion at different time steps throughout the treatment. The results obtained showed that the spectrum frequency quarters and the slope and intercept of the best fit line to the entire power spectrum both increased two times during the HIFU exposures. The Shannon entropy, however, decreased after the exposures. In conclusion, different characteristics of RF time series signal possess promising features that can be used to characterize ablated and nonablated tissues and to distinguish them from each other in a quasi-quantitative fashion.

  12. A modeling-based assessment of acousto-optic sensing for monitoring high-intensity focused ultrasound lesion formation

    Adams, Matthew Tyler

    Real-time acousto-optic (AO) sensing---a dual-wave modality that combines ultrasound with diffuse light to probe the optical properties of turbid media---has been demonstrated to non-invasively detect changes in ex vivo tissue optical properties during high-intensity focused ultrasound (HIFU) exposure. The AO signal indicates the onset of lesion formation and predicts resulting lesion volumes. Although proof-of-concept experiments have been successful, many of the underlying parameters and mechanisms affecting thermally induced optical property changes and the AO detectability of HIFU lesion formation are not well understood. In thesis, a numerical simulation was developed to model the AO sensing process and capture the relevant acoustic, thermal, and optical transport processes. The simulation required data that described how optical properties changed with heating. Experiments were carried out where excised chicken breast was exposed to thermal bath heating and changes in the optical absorption and scattering spectra (500 nm--1100 nm) were measured using a scanning spectrophotometer and an integrating sphere assembly. Results showed that the standard thermal dose model currently used for guiding HIFU treatments needs to be adjusted to describe thermally induced optical property changes. To model the entire AO process, coupled models were used for ultrasound propagation, tissue heating, and diffusive light transport. The angular spectrum method was used to model the acoustic field from the HIFU source. Spatial-temporal temperature elevations induced by the absorption of ultrasound were modeled using a finite-difference time-domain solution to the Pennes bioheat equation. The thermal dose model was then used to determine optical properties based on the temperature history. The diffuse optical field in the tissue was then calculated using a GPU-accelerated Monte Carlo algorithm, which accounted for light-sound interactions and AO signal detection. The simulation was

  13. A mitotic phosphorylation feedback network connects Cdk1, Plk1, 53BP1, and Chk2 to inactivate the G(2)/M DNA damage checkpoint

    van Vugt, Marcel A T M; Gardino, Alexandra K; Linding, Rune; Ostheimer, Gerard J; Reinhardt, H Christian; Ong, Shao-En; Tan, Chris S; Miao, Hua; Keezer, Susan M; Li, Jeijin; Pawson, Tony; Lewis, Timothy A; Carr, Steven A; Smerdon, Stephen J; Brummelkamp, Thijn R; Yaffe, Michael B

    2010-01-01

    DNA damage checkpoints arrest cell cycle progression to facilitate DNA repair. The ability to survive genotoxic insults depends not only on the initiation of cell cycle checkpoints but also on checkpoint maintenance. While activation of DNA damage checkpoints has been studied extensively, molecular...

  14. Microwaves from GSM Mobile Telephones Affect 53BP1 and γ-H2AX Foci in Human Lymphocytes from Hypersensitive and Healthy Persons

    Markovà, Eva; Hillert, Lena; Malmgren, Lars; Persson, Bertil R R; Belyaev, Igor Y.

    2005-01-01

    The data on biologic effects of nonthermal microwaves (MWs) from mobile telephones are diverse, and these effects are presently ignored by safety standards of the International Commission for Non-Ionizing Radiation Protection (ICNIRP). In the present study, we investigated effects of MWs of Global System for Mobile Communication (GSM) at different carrier frequencies on human lymphocytes from healthy persons and from persons reporting hypersensitivity to electromagnetic fields (EMFs). We meas...

  15. Human Rif1, ortholog of a yeast telomeric protein, is regulated by ATM and 53BP1 and functions in the S-phase checkpoint

    Silverman, Joshua; Takai, Hiroyuki; Buonomo, Sara B C; Eisenhaber, Frank; de Lange, Titia

    2004-01-01

    We report on the function of the human ortholog of Saccharomyces cerevisiae Rif1 (Rap1-interacting factor 1). Yeast Rif1 associates with telomeres and regulates their length. In contrast, human Rif1 did not accumulate at functional telomeres, but localized to dysfunctional telomeres and to telomeric DNA clusters in ALT cells, a pattern of telomere association typical of DNA-damage-response factors. After induction of double-strand breaks (DSBs), Rif1 formed foci that colocalized with other DN...

  16. Effect of radiation-thermal treatment with focused electron beam on fine atomic structure and carbide formation in roll steel

    Using nuclear physics methods - positron annihilation and nuclear gamma-resonance vacancy type point defects concentration and distribution changes as well as carbide phase precipitation in steel surface layers were studied. Steel for color deformation rolls was irradiated with focused 1.5 MeV electron beam at 400-550 deg C

  17. Sex And Gender Roles In Gentle And Noble Families, c.1575-1660, With A Particular Focus On Marriage Formation

    Gosling, Sally Catherine

    2000-01-01

    The thesis examines thinking about, and experiences of, gender roles and family relationships for the gentry and nobility, particularly through the process of marriage formation. The study draws on a range of sources, including collections of family letters, personal memoirs and prescriptive literature. Some chapters pursue a case study approach to correspondence. Others consider the relationship between published advice and personal attitudes and experience. The study explores whether th...

  18. Transformation of the beam intensity distribution and formation of a uniform ion beam by means of nonlinear focusing

    Avoiding undesirable thermal stress or damage of a target vessel is an essential subject in high-intensity beam irradiation for accelerator-driven neutron production. A promising method to tailor the transverse beam intensity distribution for uniform beam irradiation on the target is the use of multipole magnets. We, therefore, study the transformation and uniformization of the transverse intensity distribution by means of nonlinear focusing induced from multipole magnets. It is theoretically described how the intensity distribution is transformed and made uniform by the nonlinear focusing force. Large-area uniform proton and heavy-ion beams are experimentally formed using octupole magnets at the azimuthally-varying-field cyclotron in Japan Atomic Energy Agency. (author)

  19. Investigation of early DNA damage after radioiodine therapy in patients with thyroid cancer using the gamma-H2AX focus assay

    Full text of publication follows. Objectives: the Aim of the study is to investigate the DNA damage formation in blood lymphocytes and the correlation to the absorbed dose to the blood in patients with differentiated thyroid carcinoma (DTC) after their first radionuclide therapy with I-131 as measured by the induction, persistence and decay behaviour of γ-H2AX and 53BP1 DNA damage-induced foci. Radiation-induced DNA double strand breaks (DSBs) cause in their vicinity the formation of microscopically visible foci of the phospho-histone H2AX (γ-H2AX) and the 53BP1 protein that binds to and signals damaged chromatin at the DSB site. Nuclear foci containing both markers thus represent radiation-induced DSBs. Methods: we investigated 19 patients with DTC during the first treatment with 3.5±0.3 GBq I-131. Between 7 and 10 sequential peripheral blood samples (at least four within the first 5 hours) were taken before and between 0.5 h and 144 h post administration. The physical dosimetry procedures were performed according to the EANM DTC SOP. White blood cells were recovered by density centrifugation in CPT tubes (BD Biosciences) and subjected to two-colour immunofluorescence staining. The average frequencies of the radiation-induced γ-H2AX foci/nucleus that co localized with 53BP1 foci were derived from immuno-stained mononuclear peripheral blood lymphocyte samples. The number of foci was counted manually using a red/green double band pass filter (Chroma) in a Zeiss microscope by an experienced observer. Results: The mean I-131 absorbed dose to the blood was (0.04±0.01) Gy at t=2 h, (0.07±0.02) Gy at t=4 h, and (0.21±0.05) Gy at t=24 h, respectively. The mean value of the total absorbed dose to the blood was (0.36±0.08) Gy. The highest number of radiation-induced foci per nucleus (RIF) and per absorbed dose (median: 8.8 RIF/Gy, range 3.1-10.9 RIF/Gy) was observed in the first three hours post administration. Four hours after radioiodine administration the number

  20. Microporous and tight limestones in the Urgonian Formation (late Hauterivian to early Aptian) of the French Jura Mountains: Focus on the factors controlling the formation of microporous facies

    Volery, Chadia; Davaud, Eric; Durlet, Christophe; Clavel, Bernard; Charollais, Jean; Caline, Bruno

    2010-10-01

    Microporous and tight limestones, with contrasting porosity and permeability values directly related to the microfabric of the micritic matrix, outcrop in the Urgonian Formation of the French Jura Mountains. This study investigates the factors controlling the differentiation between the microporous and tight facies, and proposes a diagenetic model for the development and preservation of the microporosity in these limestones. The petrophysical properties are not related to the depositional texture, the petrographical content or the mineralogical composition. However, the tight layers contain indications of emersion (e.g.: bird eyes, keystone vugs, and desiccation cracks). The sedimentation in very shallow conditions up to emersion is confirmed by the covariant more positive values of oxygen and carbon isotopes. The microporous intervals systematically occur a few meters below the tight layers affected by emersion. This position strongly suggests the importance of meteoric water input rapidly after sedimentation in the differentiation between tight and microporous limestones. The diagenetic model proposed for the development and preservation of the microporous facies involves partial early cementation of the interstitial mud, mainly composed of low-Mg calcite crystals (sedimentation during a calcite sea period), inside a meteoric phreatic lens by in situ dissolution-reprecipitation processes ("hybrid Ostwald ripening"). This early cementation partly preserves the original microfabric and intercrystalline microporosity and allows the carbonate sediment to resist compaction during burial. The identification of the conditions favorable to the development of microporosity in these Urgonian limestones may improve the knowledge and modeling of some microporous carbonate reservoir rocks.

  1. Formation of Tunable, Emulsion Micro-Droplets Utilizing Flow-Focusing Channels and a Normally-Closed Micro-Valve

    Gwo-Bin Lee

    2013-07-01

    Full Text Available A mono-dispersed emulsion is of great significance in many chemical, biomedical and industrial applications. The current study reports a new microfluidic chip capable of forming tunable micro-droplets in liquids for emulsification applications. It can precisely generate size-tunable, uniform droplets using flow-focusing channels and a normally-closed valve, which is opened by a pneumatic suction force. Experimental data showed that micro-droplets with a diameter ranging from several to tens of micrometers could be precisely generated with a high uniformity. The droplet size is experimentally found to be dependent on the velocity of the dispersed-phase liquid, which is controlled by the deflection of the suction membrane. Emulsions with droplet sizes ranging from 5.5 to 55 μm are successfully observed. The variation in droplet sizes is from 3.8% to 2.5%. The micro-droplets have a uniform size and droplets smaller than those reported in previous studies are possible with this approach. This new microfluidic device can be promising for emulsification and other related applications.

  2. TopBP1 is required at mitosis to reduce transmission of DNA damage to G1 daughter cells

    Pedersen, Rune Troelsgaard; Kruse, Thomas; Nilsson, Jakob;

    2015-01-01

    mitotic entry. In early mitosis, TopBP1 marks sites of and promotes unscheduled DNA synthesis. Moreover, TopBP1 is required for focus formation of the structure-selective nuclease and scaffold protein SLX4 in mitosis. Persistent TopBP1 foci transition into 53BP1 nuclear bodies (NBs) in G1 and precise...... temporal depletion of TopBP1 just before mitotic entry induced formation of 53BP1 NBs in the next cell cycle, showing that TopBP1 acts to reduce transmission of DNA damage to G1 daughter cells. Based on these results, we propose that TopBP1 maintains genome integrity in mitosis by controlling chromatin...

  3. Focus formation and neoplastic transformation by herpes simplex virus type 2 inactivated intracellularly by 5-bromo-2'-deoxyuridine and near UV light

    The induction of focus formation in low serum and of neoplastic transformation of Syrian hamster embryo cells was examined after the expression of herpes simplex virus type 2 functions. Syrian hamster embryo cells infected at a high multiplicity (5 PFU/cell) with 5-bromo-2'-deoxyuridine-labeled herpes simplex virus type 2 (11% substitution of thymidine residues) were exposed to near UV light irradiation at various times postinfection. This procedure specifically inactivated the viral genome, while having little, if any, effect on the unlabeled cellular DNA. Focus formation in 1% serum and neoplastic transformation were observed in cells exposed to virus inactivated before infection, but the frequency was enhanced (15- to 27-fold) in cells in which the virus was inactivated at 4 to 8 h postinfection. Only 2 to 45 independently isolated foci were capable of establishing tumorigenic lines. The established lines exhibited phenotypic alterations characteristic of a transformed state, including reduced serum requirement, anchorage-independent growth, and tumorigenicity. They retained viral DNA sequences and, even at relatively late passage, expressed viral antigens, including ICP 10

  4. Upgrade with a sociocultural focus of the process of teaching-learning of the nuclear physics for the formation and professors' excellence

    When modernizing the teaching-learning procces of the nuclear physics, to put it in better correspondence with the current sociocultural context and to overcome the limitations presented in the professors formation, It have kept in mind a nucleus of ideas in those that it is synthesized the theoretical and practice experience in the field of the science didactics during the last decades. The idea defend in the investigation is that in correspondence with a sociocultural focus the process teaching-learning of the nuclear physics for the formation and professors should be structured around the most general problems that face the science, the technology and the society. The theoretical contribution of the work resides in the establishment of essential relationships among the teaching-learning of the nuclear physics, the sociocultural focus of the scientific education, the distinctive characteristics of the human psychic activity and of the activity scientist contemporary investigator, The practical contribution of the carried out work resides in the following results. a) strategy for the bring up to date of the process of teaching-learning of the nuclear physics, b) it programs of the subject the nuclear physics in the science, the technology and the society, c) systems of educational tasks, d) it structures basic of a place Web Science and nuclear Technology'', d) it programs computer of simulation of the dispersion of nuclear particles and and) I study on-line Nuclear Physics and the situation of the world'' (Author)

  5. Formation of pure Cu nanocrystals upon post-growth annealing of Cu–C material obtained from focused electron beam induced deposition: comparison of different methods

    Szkudlarek, Aleksandra; Rodrigues Vaz, Alfredo; Zhang, Yucheng; Rudkowski, Andrzej; Kapusta, Czesław; Erni, Rolf; Moshkalev, Stanislav

    2015-01-01

    Summary In this paper we study in detail the post-growth annealing of a copper-containing material deposited with focused electron beam induced deposition (FEBID). The organometallic precursor Cu(II)(hfac)2 was used for deposition and the results were compared to that of compared to earlier experiments with (hfac)Cu(I)(VTMS) and (hfac)Cu(I)(DMB). Transmission electron microscopy revealed the deposition of amorphous material from Cu(II)(hfac)2. In contrast, as-deposited material from (hfac)Cu(I)(VTMS) and (hfac)Cu(I)(DMB) was nano-composite with Cu nanocrystals dispersed in a carbonaceous matrix. After annealing at around 150–200 °C all deposits showed the formation of pure Cu nanocrystals at the outer surface of the initial deposit due to the migration of Cu atoms from the carbonaceous matrix containing the elements carbon, oxygen, and fluorine. Post-irradiation of deposits with 200 keV electrons in a transmission electron microscope favored the formation of Cu nanocrystals within the carbonaceous matrix of freestanding rods and suppressed the formation on their surface. Electrical four-point measurements on FEBID lines from Cu(hfac)2 showed five orders of magnitude improvement in conductivity when being annealed conventionally and by laser-induced heating in the scanning electron microscope chamber. PMID:26425404

  6. Focus on focusing

    The discovery and impact of the principle of strong focusing was celebrated at a history Symposium at Stanford on 25 July in the course of the 1985 US Summer School on Particle Accelerators. Burt Richter, Stanford Linac Director, who introduced all the speakers with well chosen reminders about their various contributions related to the theme of the symposium, remarked that it was an appropriate time to be lauding the great contributions of accelerator physicists following the Nobel Prize award to Simon van der Meer for outstanding achievements in accelerator physics

  7. FORMATION OF SYSTEM OF THE IS INTELLECTUAL-FOCUSED MANAGEMENT BY DEVELOPMENT OF THE ENTERPRISES OF A RAILWAY TRANSPORTATION: THE CONCEPTUAL APPROACH

    Plugina, J.

    2011-01-01

    The article disclosed the contents of a conceptual approach to the formation of an intellectually-oriented development management of the railway transport enterprises, identified the components and elements of this system.

  8. A Comparison of national CCS strategies for Northwest Europe, with a focus on the potential of common CO2 storage at the Utsira formation

    Ramirez, Andrea; Hoefnagels, Ric; van den Broek, Machteld; Strachan, Neil; Fidje, Audun; Espegren, Kari; Seljom, Pernille; Blesl, Marcus; Kober, Tom; Grohnheit, Poul Erik; Lüthje, Mikael

    2011-01-01

    saline aquifers. If these aquifers are not used, Utsira gains as competitive storage option. The main limitation for the common use of the Utsira formation appears, from a modeling point of view, to be the maximum annual injection rate for CO2 that has been assumed in the project (150 Mt CO2/yr).......Mega structures for CO2 storage, such as the Utsira formation in the North Sea, could theoretically supply CO2 storage capacity for several countries for a period of several decades. Their use could increase the cost-effectiveness of CCS in a region while minimizing opposition from the public to CO......2 storage. However, this will not only depend on their potential available capacity to store CO2 flows but also on the cost effectiveness of such an option within national portfolios of mitigation measures. This article shows key results of a research project aiming to assess the potentials and...

  9. Spatial reservoir characterisation with focus on distribution of porosity and permeability properties: - A study of the Tarbert and Ness Formations at the Gullfaks Field

    Sagen, Ina Cathrine

    2016-01-01

    This thesis aims to characterise the spatial petrophysical distribution of porosity and permeability properties in the Tarbert and Ness Formation at the Gullfaks Field. The geomodelling software Leapfrog Geo was used to build a reservoir model and estimate the spatial petrophysical properties. Four different procedures were used to obtain the results; the Geological Model (GM), the Geological Model Fault Block 2 (GM Fault Block 2), petrophysical model of the Geological Model (GM) volume and p...

  10. Circumferential lesion formation around the pulmonary veins in the left atrium with focused ultrasound using a 2D-array endoesophageal device: a numerical study

    Pichardo, Samuel; Hynynen, Kullervo [Imaging Research-Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Room C713, Toronto, ON M4N 3M5 (Canada)

    2007-08-21

    Atrial fibrillation (AF) is the most frequently sustained cardiac arrhythmia affecting humans. The electrical isolation by ablation of the pulmonary veins (PVs) in the left atrium (LA) of the heart has been proven as an effective cure of AF. The ablation consists mainly in the formation of a localized circumferential thermal coagulation of the cardiac tissue surrounding the PVs. In the present numerical study, the feasibility of producing the required circumferential lesion with an endoesophageal ultrasound probe is investigated. The probe operates at 1 MHz and consists of a 2D array with enough elements (114 x 20) to steer the acoustic field electronically in a volume comparable to the LA. Realistic anatomical conditions of the thorax were considered from the segmentation of histological images of the thorax. The cardiac muscle and the blood-filled cavities in the heart were identified and considered in the sound propagation and thermal models. The influence of different conditions of the thermal sinking in the LA chamber was also studied. The circumferential ablation of the PVs was achieved by the sum of individual lesions induced with the proposed device. Different scenarios of lesion formation were considered where ultrasound exposures (1, 2, 5 and 10 s) were combined with maximal peak temperatures (60, 70 and 80 {sup 0}C). The results of this numerical study allowed identifying the limits and best conditions for controlled lesion formation in the LA using the proposed device. A controlled situation for the lesion formation surrounding the PVs was obtained when the targets were located within a distance from the device in the range of 26 {+-} 7 mm. When combined with a maximal temperature of 70 {sup 0}C and an exposure time between 5 and 10 s, this distance ensured preservation of the esophageal structures, controlled lesion formation and delivery of an acoustic intensity at the transducer surface that is compatible with existing materials. With a peak

  11. Dense Plasma Focus Modeling

    Li, Hui [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Li, Shengtai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jungman, Gerard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hayes-Sterbenz, Anna Catherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-31

    The mechanisms for pinch formation in Dense Plasma Focus (DPF) devices, with the generation of high-energy ions beams and subsequent neutron production over a relatively short distance, are not fully understood. Here we report on high-fidelity 2D and 3D numerical magnetohydrodynamic (MHD) simulations using the LA-COMPASS code to study the pinch formation dynamics and its associated instabilities and neutron production.

  12. Interaction of weak shocks leading to Mach stem formation in focused beams and reflections from a rigid surface: numerical modeling and experiment

    KARZOVA, Maria; Salze, Edouard; Ollivier, Sébastien; Castelain, Thomas; André, Benoît; Yuldashev, Petr,; Khokhlova, Vera; Sapozhnikov, Oleg; Blanc-Benon, Philippe

    2012-01-01

    International audience Mach stem is a well-known structure observed in the process of interaction of two strong shock waves (Mach number Ma > 0.1), typically in the case of reflections from a rigid boundary. However this phenomenon has not been studied in detail for weak shocks in nonlinear acoustic fields, i.e. for acoustic Mach number in the range from 10-3 to 10-2. In acoustics, interaction of shocks occurs in the case of reflections or in the focusing of high power nonlinear beams. The...

  13. Focus: Digital

    Technology has been an all-important and defining element within the arts throughout the 20th century, and it has fundamentally changed the ways in which we produce and consume music. With this Focus we investigate the latest developments in the digital domain – and their pervasiveness and rapid...... technology affects our habits of consumption. Risto Holopainen presents a notion of autonomous instruments and automated composition that, in the end, cannot escape the human while Jøren Rudi reflects on aesthetic elements and artistic approaches to sound in computer games. This focus is edited by Sanne...

  14. Simulation model analysis of the most promising geological sequestration formation candidates in the Rocky Mountain region, USA, with focus on uncertainty assessment

    Lee, Si-Yong [Univ. of Utah, Salt Lake City, UT (United States); Zaluski, Wade [Schlumberger Carbon Services, Houston, TX (United States); Will, Robert [Schlumberger Carbon Services, Houston, TX (United States); Eisinger, Chris [Colorado Geological Survey, Golden, CO (United States); Matthews, Vince [Colorado Geological Survey, Golden, CO (United States); McPherson, Brian [Univ. of Utah, Salt Lake City, UT (United States)

    2013-12-31

    The purpose of this report is to report results of reservoir model simulation analyses for forecasting subsurface CO2 storage capacity estimation for the most promising formations in the Rocky Mountain region of the USA. A particular emphasis of this project was to assess uncertainty of the simulation-based forecasts. Results illustrate how local-scale data, including well information, number of wells, and location of wells, affect storage capacity estimates and what degree of well density (number of wells over a fixed area) may be required to estimate capacity within a specified degree of confidence. A major outcome of this work was development of a new workflow of simulation analysis, accommodating the addition of “random pseudo wells” to represent virtual characterization wells.

  15. Without 'Focus'

    Aldo Sevi

    2010-12-01

    Full Text Available It is widely accepted that a notion of 'focus', more or less as conceived of in Jackendoff (1972, must be incorporated into our theory of grammar, as a means of accounting for certain observed correlations between prosodic facts and semantic/pragmatic facts. In this paper, we put forth the somewhat radical idea that the time has come to give up this customary view, and eliminate 'focus' from our theory of grammar. We argue that such a move is both economical and fruitful.Research over the years has revealed that the correlations between prosody, 'focus', and the alleged semantic/pragmatic effects of focus are much less clear and systematic than we may have initially hoped. First we argue that this state of affairs detracts significantly from the utility of our notion of 'focus', to the point of calling into question the very motivation for including it in the grammar. Then we look at some of the central data, and show how they might be analyzed without recourse to a notion of 'focus'. We concentrate on (i the effect of pitch accent placement on discourse congruence, and (ii the choice of 'associate' for the so-called 'focus sensitive' adverb only. We argue that our focus-free approach to the data improves empirical coverage, and begins to reveal patterns that have previously been obscured by preconceptions about 'focus'.ReferencesBeaver, D. & Clark, B. 2008. Sense and Sensitivity: How Focus Determines Meaning. Blackwell.Beaver, D., Clark, B., Flemming, E., Jaeger, T. F. & Wolters, M. 2007. ‘When semantics meets phonetics: Acoustical studies of second occurrence focus’. Language 83.2: 245–76.http://dx.doi.org/10.1353/lan.2007.0053Beckman, M. & Hirschberg, J. 1994. ‘The ToBI Annotation Conventions’. Ms.,http://www.cs.columbia.edu/~julia/files/conv.pdf.Bolinger, D. 1972. ‘Accent is predictable (if you are a mind-reader’. Language 48.3: 633–44.http://dx.doi.org/10.2307/412039Büring, D. 2006. ‘Focus projection and default

  16. Self-focusing and plasma channels formation for non-axisymmetric optical schemes under different orientation of laser pulse linear polarization

    Ionin, A A; Seleznev, L V; Sinitsyn, D V; Sunchugasheva, E S; Fokina, N A

    2015-01-01

    Filamentation of linear polarized ultrashort laser pulses in non-axisymmetric optical schemes with preferential directions to the optical axis in dependence on polarization orientation was experimentally studied. Our experiments demonstrated strong influence of a laser beam polarization on self-focusing of the beam and plasma generation during filamentation. Maximum of linear plasma density generated by an astigmatic laser pulse was different in both meridional and sagittal foci and depended on the beam polarization orientation. A difference of linear plasma density was observed in the case of superposition of two parts of the laser beam going through a two-hole diaphragm depending on the beam polarization and through a slit for collinear and normal slit orientation relative to the pulse polarization. Laser pulses in IR and UV wavelength domains led to similar result.

  17. The social formation and cultural identity of Southeast Asian frontier society: Focused on the concept of maritime Zomia as frontier in connection with the ocean and the inland

    Hong Seok-Joon

    2016-06-01

    Full Text Available This paper examines the applicability of the Zomia concept for social scientific studies of the Malaysian region, with a focus on the Malaysian port cities, including Melaka. While for both empirical and socio-cultural reasons the term Zomia itself may not be entirely appropriate to the Malaysian Melaka region, the analytical implications that are based on James C. Scott’s usage of it, particularly the emphasis on the cultural dynamics of inter-ethnic, inter-national, and inter-religious relations of port areas, can be of great utility to those working in the Malaysian region. Zomia is a neologism gaining popularity with the publication of James C. Scott’s provocative book, The art of not being governed: an anarchist history of upland Southeast Asia. The term of Zomia is designed to indicate the people who has not been governed by the nation-state and national regime.

  18. Tsunami focusing

    Spillane, M. C.; Titov, V. V.; Moore, C. W.; Aydin, B.; Kanoglu, U.; Synolakis, C. E.

    2010-12-01

    Tsunamis are long waves generated by impulsive disturbances of the seafloor or coastal topography caused by earthquakes, submarine/subaerial mass failures. They evolve substantially through three dimensional - 2 spatial+1 temporal - spreading as the initial surface deformation propagates. This is referred to as its directivity and focusing. A directivity function was first defined by Ben-Menahem (1961, Bull. Seismol. Soc. Am. 51, 401-435) using the source length and the rupture velocity. Okal (2003, Pure Appl. Geophys. 160, 2189-2221) discussed the details of the analysis of Ben-Menahem (1961) and demonstrated the distinct difference between the directivity patterns of landslide and earthquake generated tsunamis. Marchuk and Titov (1989, Proc. IUGG/IOC International Tsunami Symposium, July 31 - August 3, 1989, Novosibirsk, USSR. p.11-17) described the process of tsunami focusing for a rectangular initial deformation combining positive and negative surface displacements. They showed the existence of a focusing point where abnormal tsunami wave height can be registered. Here, first, we describe and quantify numerically tsunami focusing processes for a combined positive and negative - N-wave type - strip source representing the 17 July 1998 Papua New Guinea and 17 July 2006 Java events. Specifically, considering field observations and tsunami focusing, we propose a source mechanism for the 17 July 2006 Java event. Then, we introduce a new analytical solution for a strip source propagating over a flat bottom using the linear shallow-water wave equation. The analytical solution of Carrier and Yeh (2005, Computer Modeling In Engineering & Sciences, 10(2), 113-121) appears to have two drawbacks. One, the solution involves singular complete elliptic integral of the first kind which results in a self-similar approximate solution for the far-field at large times. Two, only the propagation of Gaussian shaped finite-crest wave profiles can be modeled. Our solution is not only

  19. A continuous plasma final focus

    Scaling laws are set down for a plasma cell used for transport, focusing and current neutralization of fine, intense, relativistic electron beams. It is found that there exists a minimum beam spot size, σmin ∼ εn(IA/γI)1/2, in such a focusing system. Propagation issues, including channel formation, synchrotron radiation, beam ionization and instabilities, are discussed. Three numerical examples are considered. 38 refs., 2 figs., 1 tab

  20. Star formation

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references

  1. A continuous plasma final focus

    Scaling laws are set down for a plasma cell used for transport, focusing and current neutralization of fine, intense, relativistic electron beams. It is found that there exists a minimum beam spot size, σmin ∼ var-epsilon n(IA/γI)1/2, in such a focusing system. Propagation issues, including channel formation, synchrotron radiation, beam ionization and instabilities, are discussed. Numerical examples are given for a proof-of-principle experiment at KEK, an application for luminosity enhancement at the SLC, and a hypothetical TeV electron-positron collider. For a TeV collider, it is found that the effect of ion-motion on focusing, and the effect of Buneman instability on current neutralization must be considered. 3 figs., 1 tab

  2. Focus Intonation in Bengali

    Hasan, Md. Kamrul

    2015-01-01

    This work attempts to investigate the role of prosody in the syntax of focus in Bangla. The aim of this study is to show the intonation pattern of Bangla in emphasis and focus. In order to do that, the author has looked at the pattern of focus without-i/o as well as with the same. Do they really pose any different focus intonation pattern from…

  3. Features of dynamics of sanitary losses formation in case of large-scale radiation accidents and organization of hospital functioning when admitting the injured persons from the radiation focus

    Specific features of therapeutic-evacuation and sanitary-hygienic arrangements in case of large-scale radiation accidents are considered. The substantiation is given for the necessity of setting up to a field hospital near the focus of such an accident for rendering first medical aid and expert medical care, distribution of the injured and organization of their evacuation to specialized medical establishments in due time. 17 refs.; 1 tab

  4. Needs of Non-Energy Focused Contractors

    Liakus, C. [Building Media and the Building America Retrofit Alliance (BARA), Wilmington, DE (United States)

    2012-12-01

    To better understand the informational needs of non-energy focused contractors, including what information they need to motivate them to become energy-focused, the BARA team studied the type of information provided by the national programs, trade associations, and manufacturers that were researched for the related technical report: Effective Communication of Energy Efficiency. While that report focused on the delivery method, format, and strategy of the information, this study examines the content being put forward.

  5. Needs of Non Energy-Focused Contractors

    Liaukus, C.

    2012-12-01

    To better understand the informational needs of non energy-focused contractors, including what information they need to motivate them to become energy-focused, the BARA team studied the type of information provided by the national programs, trade associations, and manufacturers that were researched for the related technical report: Effective Communication of Energy Efficiency. While that report focused on the delivery method, format, and strategy of the information, this study examines the content being put forward.

  6. Genitive focus in Supyire

    Carlson, Robert,

    2006-01-01

    Supyire has two distinct genitive constructions, one consisting of juxtaposed nouns, and the other marked with a particle. This study demonstrates that the marked genitive correlates significantly in natural discourse with contrastive focus as operationally defined in Myhill and Xing (1996). The method used avoids the vicious circularity of many discourse-based studies of focus. Contrastive focus, rather than being "coded", is a pragmatic construal which is dependent on other elements in the ...

  7. Focus on personal mobility

    Lucas Harms, Peter Jorritsma, Nelly Kalfs

    2011-01-01

    Focus on personal mobilityVarious important societal trends, including aging, immigration, individualization and re-urbanization, influence the mobility of Dutch people. In future, these trends will lead to further (yet slowing) growth in car use, to public transport being used less in rural regions and more in urban areas, and to bicycle use claiming a smaller share of total mobility. In 'Focus on personal mobility', the Kim Netherlands Institute for Transport Policy Analysis focuses on the ...

  8. Design and characterization of a tunable opto-mechatronic system to mimic the focusing and the regulation of illumination in the formation of images made by the human eye

    Santiago-Alvarado, A.; Cruz-Félix, A.; Hernández Méndez, A.; Pérez-Maldonado, Y.; Domínguez-Osante, C.

    2015-05-01

    Tunable lenses have attracted much attention due to their potential applications in such areas like machine vision, laser projection, ophthalmology, etc. In this work we present the design of a tunable opto-mechatronic system capable of focusing and to regulate the entrance illumination that mimics the performance made by the iris and the crystalline lens of the human eye. A solid elastic lens made of PDMS has been used in order to mimic the crystalline lens and an automatic diaphragm has been used to mimic the iris of the human eye. Also, a characterization of such system has been performed with standard values of luminosity for the human eye have been taken into account to calibrate and to validate the entrance illumination levels to the overall optical system.

  9. Microfabricated particle focusing device

    Ravula, Surendra K.; Arrington, Christian L.; Sigman, Jennifer K.; Branch, Darren W.; Brener, Igal; Clem, Paul G.; James, Conrad D.; Hill, Martyn; Boltryk, Rosemary June

    2013-04-23

    A microfabricated particle focusing device comprises an acoustic portion to preconcentrate particles over large spatial dimensions into particle streams and a dielectrophoretic portion for finer particle focusing into single-file columns. The device can be used for high throughput assays for which it is necessary to isolate and investigate small bundles of particles and single particles.

  10. BrightFocus Foundation

    ... size: A A Contrast En Español Donate BrightFocus Foundation Alzheimer’s Disease Research Macular Degeneration Research National Glaucoma ... Bovenkamp, Ph.D., Scientific Program Officer for BrightFocus Foundation, about the basic science and therapeutic research the ...

  11. Geochemical and Sr-Nd isotope variations within Cretaceous continental flood-basalt suites of the Canadian High Arctic, with a focus on the Hassel Formation basalts of northeast Ellesmere Island

    Estrada, Solveig

    2015-11-01

    Early- to mid-Cretaceous flood-basalt suites of the northeast Canadian High Arctic assigned to a High Arctic Large Igneous Province (HALIP) were studied for their whole-rock geochemistry and Sr-Nd isotopes. Data from basalt flows within the upper Albian to lower Cenomanian Hassel Formation of northeast Ellesmere Island are compared with former published data and new inductively coupled plasma mass spectrometry data of the stratigraphic equivalent Strand Fiord basalts and the older, late Hauterivian to Aptian Isachsen basalts from Axel Heiberg Island. The transitional to mildly alkaline aphyric Hassel basalts, with ocean island basalt (OIB)-like geochemical signatures in parts, have an Ar-Ar whole-rock age of on average 96.4 ± 1.6 Ma. They represent two geochemically different flow units without a fractional crystallization relationship: the high-phosphorous (HP) and low-phosphorous (LP) basalts. The Hassel HP basalts differ from the LP basalts by additionally higher Ba, K, Rb, Th and LREE contents, a pronounced positive Eu anomaly (Eu/Eu* = 1.74-1.76), as well as lower Ta, Nb, Zr and Hf concentrations. The Nd and Sr isotope ratios of the Hassel HP basalts [ ɛ Nd( t) of -1.3 to -1.4, 87Sr/86Sr( t) of 0.70706-0.70707] and the LP basalts [ ɛ Nd( t) of 4.5-4.9, 87Sr/86Sr( t) of 0.7038-0.7040] indicate an origin from different mantle sources. The geochemically similar tholeiitic Isachsen (ca. 130-113 Ma) and Strand Fiord basalts (ca. 105-95 Ma) are also incompatible element enriched relative to the primitive mantle, however, with negative Sr-P anomalies as well as partially negative K, Ta and Nb anomalies. In terms of incompatible element ratios (Zr/Nb, Nb/Th), several mantle components are involved in the formation of the flood-basalt suites: a component with primitive mantle composition, an OIB-like component (probably subducted and recycled oceanic crust) and an enriched lithospheric component. The latter component, probably metasomatized subcontinental

  12. Absorption driven focus shift

    Harrop, N.; Wolf, S.; Maerten, O.; Dudek, K.; Ballach, S.; Kramer, R.

    2016-03-01

    Modern high brilliance near infrared lasers have seen a tremendous growth in applications throughout the world. Increased productivity has been achieved by higher laser power and increased brilliance of lasers. Positive impacts on the performance and costs of parts are opposed to threats on process stability and quality, namely shift of focus position over time. A high initial process quality will be reduced by contamination of optics, eventually leading to a focus shift or even destruction of the optics. Focus analysis at full power of multi-kilowatt high brilliance lasers is a very demanding task because of high power densities in the spot and the high power load on optical elements. With the newly developed high power projection optics, the High-Power Micro-Spot Monitor High Brilliance (HP-MSM-HB) is able to measure focus diameter as low as 20 μm at power levels up to 10 kW at very low internal focus shift. A main driving factor behind thermally induced focus shift is the absorption level of the optical element. A newly developed measuring system is designed to determine the relative absorption level in reference to a gold standard. Test results presented show a direct correlation between absorption levels and focus shift. The ability to determine the absorption level of optical elements as well as their performance at full processing power before they are put to use, enables a high level of quality assurance for optics manufacturers and processing head manufacturers alike.

  13. New focused crawling algorithm

    Su Guiyang; Li Jianhua; Ma Yinghua; Li Shenghong; Song Juping

    2005-01-01

    Focused carawling is a new research approach of search engine. It restricts information retrieval and provides search service in specific topic area. Focused crawling search algorithm is a key technique of focused crawler which directly affects the search quality. This paper first introduces several traditional topic-specific crawling algorithms, then an inverse link based topic-specific crawling algorithm is put forward. Comparison experiment proves that this algorithm has a good performance in recall, obviously better than traditional Breadth-First and Shark-Search algorithms. The experiment also proves that this algorithm has a good precision.

  14. Focus on Compression Stockings

    ... therapy may be recommended as part of a treatment plan. There are several situations when compression may be helpful, including: tired legs, varicose veins, chronic venous insufficiency (CVI), lymphedema, or deep vein thrombosis (DVT). This brochure focuses ...

  15. Final focus test beam

    This report discusses the following: the Final Focus Test Beam Project; optical design; magnets; instrumentation; magnetic measurement and BPM calibration; mechanical alignment and stabilization; vacuum system; power supplies; control system; radiation shielding and personnel protection; infrastructure; and administration

  16. Focus group discussions

    Hennink, Monique M

    2014-01-01

    The Understanding Research series focuses on the process of writing up social research. The series is broken down into three categories: Understanding Statistics, Understanding Measurement, and Understanding Qualitative Research. The books provide researchers with guides to understanding, writing, and evaluating social research. Each volume demonstrates how research should be represented, including how to write up the methodology as well as the research findings. Each volume also reviews how to appropriately evaluate published research. Focus Group Discussions addresses the challenges associated with conducting and writing focus group research. It provides detailed guidance on the practical and theoretical considerations in conducting focus group discussions including: designing the discussion guide, recruiting participants, training a field team, moderating techniques and ethical considerations. Monique Hennink describes how a methodology section is read and evaluated by others, such as journal reviewers or ...

  17. Community-focused strategies

    2010-01-01

    This article introduces the notion of community-focused strategies to refer to the set of actions, activities and policies that firms undertake to establish connections or relational links with one or more target communities of (potential) customers. Drawing on social identity theory and strategy research, this study begins with a proposed taxonomy of different community-focused strategies. Then it illustrates how such strategies contribute to the creation of competitive advantage and explore...

  18. High harmonics focusing undulator

    Varfolomeev, A.A.; Hairetdinov, A.H.; Smirnov, A.V.; Khlebnikov, A.S. [Kurchatov Institute, Moscow (Russian Federation)

    1995-12-31

    It was shown in our previous work that there exist a possibility to enhance significantly the {open_quote}natural{close_quote} focusing properties of the hybrid undulator. Here we analyze the actual undulator configurations which could provide such field structure. Numerical simulations using 2D code PANDIRA were carried out and the enhanced focusing properties of the undulator were demonstrated. The obtained results provide the solution for the beam transport in a very long (short wavelength) undulator schemes.

  19. Electron beam focusing system

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  20. Plutonium focus area

    To ensure research and development programs focus on the most pressing environmental restoration and waste management problems at the U.S. Department of Energy (DOE), the Assistant Secretary for the Office of Environmental Management (EM) established a working group in August 1993 to implement a new approach to research and technology development. As part of this new approach, EM developed a management structure and principles that led to the creation of specific Focus Areas. These organizations were designed to focus the scientific and technical talent throughout DOE and the national scientific community on the major environmental restoration and waste management problems facing DOE. The Focus Area approach provides the framework for intersite cooperation and leveraging of resources on common problems. After the original establishment of five major Focus Areas within the Office of Technology Development (EM-50, now called the Office of Science and Technology), the Nuclear Materials Stabilization Task Group (EM-66) followed the structure already in place in EM-50 and chartered the Plutonium Focus Area (PFA). The following information outlines the scope and mission of the EM, EM-60, and EM-66 organizations as related to the PFA organizational structure

  1. The Conic Benchmark Format

    Friberg, Henrik A.

    This document constitutes the technical reference manual of the Conic Benchmark Format with le extension: .cbf or .CBF. It unies linear, second-order cone (also known as conic quadratic) and semidenite optimization with mixed-integer variables. The format has been designed with benchmark libraries...... in mind, and therefore focuses on compact and easily parsable representations. The problem structure is separated from the problem data, and the format moreover facilitate benchmarking of hotstart capability through sequences of changes....

  2. EDITORIAL: Focus on Plasmonics FOCUS ON PLASMONICS

    Bozhevolnyi, Sergey; García-Vidal, Francisco

    2008-10-01

    Plasmonics is an emerging field in optics dealing with the so-called surface plasmons whose extraordinary properties are being both analyzed from a fundamental point of view and exploited for numerous technological applications. Surface plasmons associated with surface electron density oscillations decorating metal dielectric interfaces were discovered by Rufus Ritchie in the 1950s. Since the seventies, the subwavelength confinement of electromagnetic fields as well as their enhancement inherent to the surface plasmon excitation has been widely used for spectroscopic purposes. Recent advances in nano-fabrication, characterization and modelling techniques have allowed unique properties of these surface electromagnetic modes to be explored with respect to subwavelength field localization and waveguiding, opening the path to truly nanoscale plasmonic optical devices. This area of investigation also has interesting links with research on photonic band gap materials and the field of optical metamaterials. Nowadays, plasmonics can be seen as a mature interdisciplinary area of research in which scientists coming from different backgrounds (chemistry, physics, optics and engineering) strive to discover and exploit new and exciting phenomena associated with surface plasmons. The already made and forthcoming discoveries will have impacts in many fields of science and technology, including not only photonics and materials science but also computation, biology and medicine, among others. This focus issue of New Journal of Physics is intended to cover all the aforementioned capabilities of surface plasmons by presenting a current overview of state-of-the-art advances achieved by the leading groups in this field of research. Focus on Plasmonics Contents Directional coupling between dielectric and long-range plasmon waveguides Aloyse Degiron, Sang-Yeon Cho, Talmage Tyler, Nan Marie Jokerst and David R Smith Nanoantenna array-induced fluorescence enhancement and reduced lifetimes

  3. Decontamination & decommissioning focus area

    NONE

    1996-08-01

    In January 1994, the US Department of Energy Office of Environmental Management (DOE EM) formally introduced its new approach to managing DOE`s environmental research and technology development activities. The goal of the new approach is to conduct research and development in critical areas of interest to DOE, utilizing the best talent in the Department and in the national science community. To facilitate this solutions-oriented approach, the Office of Science and Technology (EM-50, formerly the Office of Technology Development) formed five Focus AReas to stimulate the required basic research, development, and demonstration efforts to seek new, innovative cleanup methods. In February 1995, EM-50 selected the DOE Morgantown Energy Technology Center (METC) to lead implementation of one of these Focus Areas: the Decontamination and Decommissioning (D & D) Focus Area.

  4. The focus factor

    Nicolaisen, Jeppe; Frandsen, Tove Faber

    2015-01-01

    Introduction. We present a new bibliometric indicator to measure journal specialisation over time, named the focus factor. This new indicator is based on bibliographic coupling and counts the percentage of re-citations given in subsequent years. Method. The applicability of the new indicator is...... validate re-citations as caused by specialisation, other possible causes were measured and correlated (obsolescence, journal self-citations and number of references). Results. The results indicate that the focus factor is capable of distinguishing between general and specialised journals and thus...... effectively measures the intended phenomenon (i.e., journal specialisation). Only weak correlations were found between journal re-citations and obsolescence, journal self-citations, and number of references. Conclusions. The focus factor successfully measures journal specialisation over time. Measures based...

  5. Radiological focusing techniques

    The textbook explains the most common and essential radiological focusing techniques and gives the relevant theory and technical fundamentals. The theory does not consume much space in this book, the theoretical part briefly addressing such aspects as film-screen combinations, doses administered by X-ray radiography, quality assurance, radiological protection, and potential patient reactions to contrast media applied. The textbook primarily is a practical guide giving general advice and guidance on focusing techniques, accompanied by an illustrative compilation of frequent mistakes. Arranged by body regions, the well over 80 examples of focusing techniques are presented by systematic texts and illustrations. There is an annex giving a glossary of terms, a bibliography, and a list of useful addresses. (orig./MG)

  6. A Material Focus

    Vallgårda, Anna K. A.; Sokoler, Tomas

    2009-01-01

    In this paper we build on the notion of computational composites, which hold a material perspective on computational technology. We argue that a focus on the material aspects of the technology could be a fruitful approach to achieve new expressions and to gain a new view on the technology's role in...

  7. Focus: International Economics.

    Lynch, Gerald J.; Watts, Michael W.; Wentworth, Donald R.

    The "Focus" series, part of the National Council on Economic Education's (NCEE) EconomicsAmerica program, uses economics to enhance learning in subjects such as history, geography, civics, and personal finance, as well as economics. Activities are interactive, reflecting the belief that students learn best through active, highly personalized…

  8. Focus: Economic Systems.

    McCorkle, Sarapage; Meszaros, Bonnie T.; Odorzynski, Sandra J.; Schug, Mark C.; Watts, Michael

    The "Focus" series, part of the National Council on Economic Education's (NCEE) EconomicsAmerica program, uses economics to enhance learning in subjects such as history, geography, civics, and personal finance, as well as economics. Activities are interactive, reflecting the belief that students learn best through active, highly personalized…

  9. Homework. Focus On

    Rahal, Michelle Layer

    2010-01-01

    Homework has been an integral part of the educational system for over 100 years. What likely began as simple memorization tasks has evolved into complex projects and sparked an increasingly heated debate over the purpose and value of homework assignments. This "Focus On" examines the purpose of homework, how to create homework that has value,…

  10. Focus on stochastic thermodynamics

    Van den Broeck, Christian; Sasa, Shin-ichi; Seifert, Udo

    2016-02-01

    We introduce the thirty papers collected in this ‘focus on’ issue. The contributions explore conceptual issues within and around stochastic thermodynamics, use this framework for the theoretical modeling and experimental investigation of specific systems, and provide further perspectives on and for this active field.

  11. Formate Formation and Formate Conversion in Biological Fuels Production

    Bryan R. Crable

    2011-01-01

    Full Text Available Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production.

  12. Focusing of electromagnetic waves

    The focusing of electromagnetic waves inside a slab has been examined together with two special cases in which the slab is reduced to a single interface or a single medium. To that end the exact solutions for the fields inside a layered medium have been used, given in terms of the outside current source in order to obtain the solutions for the focused electric field inside a slab. Both exact and asymptotic solutions of the problem have been considered, and the validity of the latter has been discussed. The author has developed a numerical algorithm for evaluation of the diffraction integral with special emphasis on reducing the computing time. The numerical techniques in the paper can be readily applied to evaluate similar diffraction integrals occurring e.g. in microstrip antennas. 46 refs

  13. Focusing aerogel RICH optimization

    The method of improvement of Cherenkov angle resolution in RICH detectors using 'focusing' aerogel radiators (FARICH) is under investigation. The 'focusing' three-layer aerogel radiator was investigated using a digital radiographic device. The Monte Carlo calculations of velocity resolution based on measured variations of the refractive index in aerogel tile are presented. With the observed variations, π- and K-mesons can be separated up to 8.4 GeV/c, π- and μ-mesons can be separated up to 1.6GeV/c. We studied the use of sodium fluoride radiator in a RICH detector. NaF radiator extends the working momentum region for the π/K identification down to 0.6 GeV/c. It has been shown that a RICH detector with NaF radiator can achieve a competitive velocity resolution up to 5 GeV/c as compared to single-layer aerogel RICH

  14. Plutonium focus area. Technology summary

    The Assistant Secretary for the Office of Environmental Management (EM) at the U.S. Department of Energy (DOE) chartered the Plutonium Focus Area (PFA) in October 1995. The PFA open-quotes...provides for peer and technical reviews of research and development in plutonium stabilization activities...close quotes In addition, the PFA identifies and develops relevant research and technology. The purpose of this document is to focus attention on the requirements used to develop research and technology for stabilization, storage, and preparation for disposition of nuclear materials. The PFA Technology Summary presents the approach the PFA uses to identify, recommend, and review research. It lists research requirements, research being conducted, and gaps where research is needed. It also summarizes research performed by the PFA in the traditional research summary format. This document encourages researchers and commercial enterprises to do business with PFA by submitting research proposals or open-quotes white papers.close quotes In addition, it suggests ways to increase the likelihood that PFA will recommend proposed research to the Nuclear Materials Stabilization Task Group (NMSTG) of DOE

  15. Divergent flow isoelectric focusing

    Šlais, Karel

    2008-01-01

    Roč. 29, č. 12 (2008), s. 2451-2457. ISSN 0173-0835 R&D Projects: GA AV ČR IAAX00310701; GA ČR GA203/06/1179 Institutional research plan: CEZ:AV0Z40310501 Keywords : isoelectric focusing * divergent flow * pI markers Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.509, year: 2008

  16. Divergent flow isoelectric focusing

    Šlais, Karel

    Budapest: Hungarian Society for Separation Sciences, 2007. s. 45. ISBN 978-963-06-2925-6. [Balaton Symposium on High-Performance /7./. 05.09.2007-07.09.2007, Siofok] R&D Projects: GA AV ČR IAAX00310701; GA ČR GA203/06/1179 Institutional research plan: CEZ:AV0Z40310501 Keywords : isoelectric focusing * divergent flow * pI markers Subject RIV: CB - Analytical Chemistry, Separation

  17. Disjunction, focus, and scope

    Han, Chung-Hye; Romero, Maribel

    2004-01-01

    This paper presents the observation that disjunction cannot take wide scope in negative non-wh-questions and declaratives with a preposed negative element. This rules out the alternative question reading for non-wh-questions with preposed negation and the wide-scope or reading for neg-inverted declaratives. We show that effects parallel to the ones associated with preposed negation can be reproduced in affirmative non-wh-questions and declaratives when Focus is involved. We propose that prepo...

  18. Subsurface contaminants focus area

    NONE

    1996-08-01

    The US Department of Enregy (DOE) Subsurface Contaminants Focus Area is developing technologies to address environmental problems associated with hazardous and radioactive contaminants in soil and groundwater that exist throughout the DOE complex, including radionuclides, heavy metals; and dense non-aqueous phase liquids (DNAPLs). More than 5,700 known DOE groundwater plumes have contaminated over 600 billion gallons of water and 200 million cubic meters of soil. Migration of these plumes threatens local and regional water sources, and in some cases has already adversely impacted off-site rsources. In addition, the Subsurface Contaminants Focus Area is responsible for supplying technologies for the remediation of numerous landfills at DOE facilities. These landfills are estimated to contain over 3 million cubic meters of radioactive and hazardous buried Technology developed within this specialty area will provide efective methods to contain contaminant plumes and new or alternative technologies for development of in situ technologies to minimize waste disposal costs and potential worker exposure by treating plumes in place. While addressing contaminant plumes emanating from DOE landfills, the Subsurface Contaminants Focus Area is also working to develop new or alternative technologies for the in situ stabilization, and nonintrusive characterization of these disposal sites.

  19. Subsurface contaminants focus area

    The US Department of Enregy (DOE) Subsurface Contaminants Focus Area is developing technologies to address environmental problems associated with hazardous and radioactive contaminants in soil and groundwater that exist throughout the DOE complex, including radionuclides, heavy metals; and dense non-aqueous phase liquids (DNAPLs). More than 5,700 known DOE groundwater plumes have contaminated over 600 billion gallons of water and 200 million cubic meters of soil. Migration of these plumes threatens local and regional water sources, and in some cases has already adversely impacted off-site rsources. In addition, the Subsurface Contaminants Focus Area is responsible for supplying technologies for the remediation of numerous landfills at DOE facilities. These landfills are estimated to contain over 3 million cubic meters of radioactive and hazardous buried Technology developed within this specialty area will provide efective methods to contain contaminant plumes and new or alternative technologies for development of in situ technologies to minimize waste disposal costs and potential worker exposure by treating plumes in place. While addressing contaminant plumes emanating from DOE landfills, the Subsurface Contaminants Focus Area is also working to develop new or alternative technologies for the in situ stabilization, and nonintrusive characterization of these disposal sites

  20. Reengineering Activities in K-8 Classrooms: Focus on Formative Feedback

    Foster, Patrick N.

    2006-01-01

    Almost every K-8 technology activity includes feedback. Technology teachers generally view the input-process-output paradigm as being incomplete. A step toward completion would be the inclusion of a "feedback" component incorporating reengineering. This article provides an example of how one activity evolved through several stages to include…

  1. Focus on Organic Conductors

    Shinya Uji, Takehiko Mori and Toshihiro Takahashi

    2009-01-01

    Full Text Available Organic materials are usually thought of as electrical insulators. Progress in chemical synthesis, however, has brought us a rich variety of conducting organic materials, which can be classified into conducting polymers and molecular crystals. Researchers can realize highly conducting molecular crystals in charge-transfer complexes, where suitable combinations of organic electron donor or acceptor molecules with counter ions or other organic molecules provide charge carriers. By means of a kind of chemical doping, the charge-transfer complexes exhibit high electrical conductivity and, thanks to their highly crystalline nature, even superconductivity has been observed. This focus issue of Science and Technology of Advanced Materials is devoted to the research into such 'organic conductors'The first organic metal was (TTF(TCNQ, which was found in 1973 to have high conductivity at room temperature and a metal–insulator transition at low temperatures. The first organic superconductor was (TMTSF2PF6, whose superconductivity under high pressures was reported by J´erome in 1980. After these findings, the research on organic conductors exploded. Hundreds of organic conductors have been reported, among which more than one hundred exhibit superconductivity. Recently, a single-component organic conductor has been found with metallic conductivity down to low temperatures.In these organic conductors, in spite of their simple electronic structures, much new physics has arisen from the low dimensionality. Examples are charge and spin density waves, characteristic metal–insulator transitions, charge order, unconventional superconductivity, superconductor–insulator transitions, and zero-gap conductors with Dirac cones. The discovery of this new physics is undoubtedly derived from the development of many intriguing novel organic conductors. High quality single crystals are indispensable to the precise measurement of electronic states.This focus issue

  2. Focused crossed Andreev reflection

    Haugen, H.; Brataas, A.; Waintal, X.; Bauer, G. E. W.

    2011-03-01

    We consider non-local transport mediated by Andreev reflection in a two-dimensional electron gas (2DEG) connected to one superconducting and two normal metal terminals. A robust scheme is presented for observing crossed Andreev reflection (CAR) between the normal metal terminals based on electron focusing by weak perpendicular magnetic fields. At slightly elevated temperatures the CAR signature can be easily distinguished from a background of quantum interference fluctuations. The CAR-induced entanglement between electrons can be switched on and off over large distances by the magnetic field.

  3. Digital focusing schlieren imaging

    Buckner, Benjamin D.; Trolinger, James D.; L'Esperance, Drew

    2015-09-01

    Since its invention in the 19th century, schlieren imaging has been an essential method for studying many aerodynamic effects, particularly convection and shock waves, but the classical method using parabolic mirrors is extremely difficult to set up and very expensive for large fields of view. Focusing schlieren methods have made large- area schlieren more feasible but have tended to be difficult to align and set up, limiting their utility in many applications We recently developed an alternative approach which utilizes recent advances in digital display technology to produce simpler schlieren system that yields similar sensitivity with greater flexibility.

  4. Antiproton Focus Horn

    1974-01-01

    Was used for the AA (antiproton accumulator). Making an antiproton beam took a lot of time and effort. Firstly, protons were accelerated to an energy of 26 GeV in the PS and ejected onto a metal target. From the spray of emerging particles, a magnetic horn picked out 3.6 GeV antiprotons for injection into the AA through a wide-aperture focusing quadrupole magnet.For a million protons hitting the target, just one antiproton was captured, 'cooled' and accumulated. It took 3 days to make a beam of 3 x 10^11 -, three hundred thousand million - antiprotons.

  5. Rheological phenomena in focus

    Boger, DV

    1993-01-01

    More than possibly any other scientific discipline, rheology is easily visualized and the relevant literature contains many excellent photographs of unusual and often bizarre phenomena. The present book brings together these photographs for the first time. They are supported by a full explanatory text. Rheological Phenomena in Focus will be an indispensable support manual to all those who teach rheology or have to convince colleagues of the practical relevance of the subject within an industrial setting. For those who teach fluid mechanics, the book clearly illustrates the difference be

  6. CERN In Focus

    CERN audiovisual service

    2008-01-01

    First edition 2008 of Cern in Focus. On behalf of the audiovisual team, a selection of the latest videos filmed at CERN. Every six weeks, we will bring you the latest in CERN's activities, from LHC start up to the Computing Grid, featuring the experiments and many other goings-on at CERN. The agenda of this first edition of CERN in Focus features the visit of the prime minister of Malta, Lawrence Gonzi... CMS and the final descent of the YE-1 end cap... The departure of UA1 magnets to Japan... The start up of sectors 4 and 5... And finally, in our sports round up... We'll talk about football. New in brief this month... The final bolt is in place : On 7th November, in the bowels of the LHC tunnel, CERN's Director General Robert Aymar tightened a gold-plated bolt for the last arc interconnection of sector 1-2. This symbolic gesture marks the completion of all the arc interconnections of the LHC. Last welding work: it was never going to be an easy task. On this day last year just one sector had been completed,...

  7. Focus on Russia

    The section Focus on Russia holds 3 articles and two columns. The first article looks at the close affiliation between the Russian president Medvedev and Gazprom. However, with energy prices going down, the growing risks for Gazprom might also become a risk for Medvedev. In the second article it is argued that the gas conflict between Ukraine and Russia is not what it appears to be in the western media. It has been going on for at least 15 years and it is really a war between private parties in Russia and Ukraine who engage in illicit gas trading. Article 3 discusses the Chinese threat. While the US and Europe compete for Shtokman gas, China is increasingly asserting itself as an attractive market for Russian energy. Yet, in the end, Russia will give Europe preference, according to the author

  8. Plasma focus neutron source

    A neutron source not permanently active is obtained from an electric discharge plasma focus (PF) device. A small PF device, a Mather model device, works in the limit of low energy, 100 to 200 J at charging voltage of 20 to 30 kV with a capacitor bank of 160 nF, and a characteristic inductance of 25 to 50 nH. A theoretical model leads us to estimate the optimum values of capacitance, inductance, initial charging voltage and electrode geometry. In this work is presented the design evolution and construction of a first PF neutron source prototype, preliminary measures of current, voltage and temporal evolution of the current with the end of have an electric characterization. This parameters must be optimized with the objective of geeting an emission of 104 to 105 neutrons per pulse when Deuterium is used like filled gas (C.W)

  9. Focused Ultrasound and Lithotripsy.

    Ikeda, Teiichiro; Yoshizawa, Shin; Koizumi, Norihiro; Mitsuishi, Mamoru; Matsumoto, Yoichiro

    2016-01-01

    Shock wave lithotripsy has generally been a first choice for kidney stone removal. The shock wave lithotripter uses an order of microsecond pulse durations and up to a 100 MPa pressure spike triggered at approximately 0.5-2 Hz to fragment kidney stones through mechanical mechanisms. One important mechanism is cavitation. We proposed an alternative type of lithotripsy method that maximizes cavitation activity to disintegrate kidney stones using high-intensity focused ultrasound (HIFU). Here we outline the method according to the previously published literature (Matsumoto et al., Dynamics of bubble cloud in focused ultrasound. Proceedings of the second international symposium on therapeutic ultrasound, pp 290-299, 2002; Ikeda et al., Ultrasound Med Biol 32:1383-1397, 2006; Yoshizawa et al., Med Biol Eng Comput 47:851-860, 2009; Koizumi et al., A control framework for the non-invasive ultrasound the ragnostic system. Proceedings of 2009 IEEE/RSJ International Conference on Intelligent Robotics and Systems (IROS), pp 4511-4516, 2009; Koizumi et al., IEEE Trans Robot 25:522-538, 2009). Cavitation activity is highly unpredictable; thus, a precise control system is needed. The proposed method comprises three steps of control in kidney stone treatment. The first step is control of localized high pressure fluctuation on the stone. The second step is monitoring of cavitation activity and giving feedback on the optimized ultrasound conditions. The third step is stone tracking and precise ultrasound focusing on the stone. For the high pressure control we designed a two-frequency wave (cavitation control (C-C) waveform); a high frequency ultrasound pulse (1-4 MHz) to create a cavitation cloud, and a low frequency trailing pulse (0.5 MHz) following the high frequency pulse to force the cloud into collapse. High speed photography showed cavitation collapse on a kidney stone and shock wave emission from the cloud. We also conducted in-vitro erosion tests of model and natural

  10. Retroreflection Focusing Schlieren System

    Heineck, James T. (Inventor)

    1996-01-01

    A retroreflective type focusing schlieren system which permits the light source to be positioned on the optic side of the system is introduced. The system includes an extended light source, as opposed to a point source, located adjacent to a beam splitter which projects light through the flow field onto a reflecting grating in the form of a grid which generates sheets of light that are directed back through the flow field and the beam splitter onto a primary lens behind which is located a cut-off grid having a grid pattern which corresponds to the grid pattern of the reflecting grating. The cut-off grid is adjustably positioned behind the primary lens and an image plane for imaging the turbulence is adjustably located behind the cut-off grid.

  11. Doing focus group research

    Lindegaard, Laura Bang

    2014-01-01

    interview data can be of some use if the distinction between natural and contrived data is given up and replaced with a distinction between interview data as topic or as resource. In greater detail, such scholars argue that interview data are perfectly adequate if the researcher wants to study the topic of......Scholars of ethnomethodologically informed discourse studies are often sceptical of the use of interview data such as focus group data. Some scholars quite simply reject interview data with reference to a general preference for so-called naturally occurring data. Other scholars acknowledge that...... interview interaction, but inadequate as data for studying phenomena that go beyond the phenomenon of interview interaction. Neither of these more and less sceptical positions are, on the face of it, surprising due to the ethnomethodological commitment to study social order as accomplished in situ, not as...

  12. Focusing on customer service.

    1996-01-01

    This booklet is devoted to a consideration of how good customer service in family planning programs can generate demand for products and services, bring customers back, and reduce costs. Customer service is defined as increasing client satisfaction through continuous concern for client preferences, staff accountability to clients, and respect for the rights of clients. Issues discussed include the introduction of a customer service approach and gaining staff commitment. The experience of PROSALUD in Bolivia in recruiting appropriate staff, supervising staff, soliciting client feedback, and marketing services is offered as an example of a successful customer service approach. The key customer service functions are described as 1) establishing a welcoming atmosphere, 2) streamlining client flow, 3) personalizing client services, and 4) organizing and providing clear information to clients. The role of the manager in developing procedures is explored, and the COPE (Client-Oriented Provider-Efficient) process is presented as a good way to begin to make improvements. Techniques in staff training in customer service include brainstorming, role playing, using case studies (examples of which are provided), and engaging in practice sessions. Training also leads to the development of effective customer service attitudes, and the differences between these and organizational/staff-focused attitudes are illustrated in a chart. The use of communication skills (asking open-ended questions, helping clients express their concerns, engaging in active listening, and handling difficult situations) is considered. Good recovery skills are important when things go wrong. Gathering and using client feedback is the next topic considered. This involves identifying, recording, and discussing customer service issues as well as taking action on these issues and evaluating the results. The booklet ends by providing a sample of customer service indicators, considering the maintenance of a

  13. Effect of age on the sensitivity of the rat thyroid gland to ionizing radiation

    Exposure to ionizing radiation during childhood is a well-known risk factor for thyroid cancer. Our study evaluated the effect of age on the radiosensitivity of rat thyroid glands. Four-week-old (4W), 7-week-old (7W), and 8-month-old (8M) male Wistar rats were exposed to 8 Gy of whole-body X-ray irradiation. Thyroids were removed 3–72 h after irradiation, and non-irradiated thyroids served as controls. Ki67-positivity and p53 binding protein 1 (53BP1) focus formation (a DNA damage response) were evaluated via immunohistochemistry. Amounts of proteins involved in DNA damage response (p53, p53 phosphorylated at serine 15, p21), apoptosis (cleaved caspase-3), and autophagy (LC3, p62) were determined via western blotting. mRNA levels of 84 key autophagy-related genes were quantified using polymerase chain reaction arrays. Ki67-positive cells in 4W (with high proliferative activity) and 7W thyroids significantly decreased in number post-irradiation. The number of 53BP1 foci and amount of p53 phosphorylated at serine 15 increased 3 h after irradiation, regardless of age. No increase in apoptosis or in the levels of p53, p21 or cleaved caspase-3 was detected for any ages. Levels of LC3-II and p62 increased in irradiated 4W but not 8M thyroids, whereas expression of several autophagy-related genes was higher in 4W than 8M irradiated thyroids. Irradiation increased the expression of genes encoding pro-apoptotic proteins in both 4W and 8M thyroids. In summary, no apoptosis or p53 accumulation was noted, despite the expression of some pro-apoptotic genes in immature and adult thyroids. Irradiation induced autophagy in immature, but not in adult, rat thyroids. (author)

  14. Focusing on flu

    Short, Mary B; Middleman, Amy B

    2014-01-01

    Introduction: To describe adolescents' perspectives regarding the use of school-located immunization programs (SLIP) for influenza vaccination. More importantly, adolescents were asked what factors would make them more or less likely to use a SLIP offering influenza vaccine. Results: Participants were generally found to be knowledgeable about influenza and to have positive attitudes toward receiving the vaccine via SLIP. Students were more willing to participate in a SLIP if it were low cost or free, less time-consuming than going to a doctor, and if they felt they could trust vaccinators. Overall, high school and middle school students ranked the benefits of SLIP similarly to each other. Methods: Focus groups using nominal group method were conducted with middle and high school students in a large, urban school district. Responses were recorded by each school, and then, responses were ranked across all participating schools for each question. Conclusions: A wide range of issues are important to middle and high school students when considering participation in SLIPs including convenience, public health benefits, trust in the program, program safety, and sanitary issues. Further research will be needed regarding the generalizability of these findings to larger populations of students. PMID:24018398

  15. Stellar formation

    Reddish, V C

    1978-01-01

    Stellar Formation brings together knowledge about the formation of stars. In seeking to determine the conditions necessary for star formation, this book examines questions such as how, where, and why stars form, and at what rate and with what properties. This text also considers whether the formation of a star is an accident or an integral part of the physical properties of matter. This book consists of 13 chapters divided into two sections and begins with an overview of theories that explain star formation as well as the state of knowledge of star formation in comparison to stellar structure

  16. Prostate Focused Ultrasound Therapy.

    Chapelon, Jean-Yves; Rouvière, Olivier; Crouzet, Sébastien; Gelet, Albert

    2016-01-01

    The tremendous progress in engineering and computing power coupled with ultrasound transducer technology and imaging modalities over the past 20 years have encouraged a revival of clinical interest in ultrasound therapy, mainly in High-Intensity Focused Ultrasound (HIFU). So far, the most extensive results from HIFU obtained in urology involve transrectal prostate ablation, which appears to be an effective therapeutic alternative for patients with malignant prostate tumors. Prostate cancer (PCa) is one of the most frequently diagnosed cancers in men. Several treatment options with different therapeutic approaches exist, including HIFU for localized PCa that has been in use for over 15 years. Since the early 2000s, two systems have been marketed for this application, and other devices are currently in clinical trials. HIFU treatment can be used either alone or in combination with (before- or after-) external beam radiotherapy (EBRT) (before or after HIFU) and can be repeated multiple times. HIFU treatment is performed under real-time monitoring with ultrasound or guided by MRI. Two indications are validated today: Primary care treatment and EBRT failure. The results of HIFU for primary care treatment are similar to standard conformal EBRT, even though no randomized comparative studies have been performed and no 10-year follow up data is yet available for HIFU. Salvage HIFU after EBRT failure is increasing with oncological outcomes, similar to those achieved with surgery but with the advantage of fewer adverse effects. HIFU is an evolving technology perfectly adapted for focal treatment. Thus, HIFU focal therapy is another pathway that must be explored when considering the accuracy and reliability for PCa mapping techniques. HIFU would be particularly suited for such a therapy since it is clear that HIFU outcomes and toxicity are relative to the volume of prostate treated. PMID:26486330

  17. Galaxy formation

    Galaxy formation is at the forefront of observation and theory in cosmology. An improved understanding is essential for improving our knowledge both of the cosmological parameters, of the contents of the universe, and of our origins. In these lectures intended for graduate students, galaxy formation theory is reviewed and confronted with recent observational issues. In lecture 1, the following topics are presented: star formation considerations, including IMF, star formation efficiency and star formation rate, the origin of the galaxy luminosity function, and feedback in dwarf galaxies. In lecture 2, we describe formation of disks and massive spheroids, including the growth of supermassive black holes, negative feedback in spheroids, the AGN-star formation connection, star formation rates at high redshift and the baryon fraction in galaxies.

  18. Approach focused on people

    Roa Ruben

    2010-11-01

    Full Text Available Family and community medicine assumes a new epistemological landmark that also provides the use of instruments and tools related to it. This care model permits carrying out a visit where all categories which the health-disease process is expressed are present. Family Medicine intends to combine both visions and, for such, it gifts elements to incorporate disease as an essential part of our patient's approach systematic being the main focus the approach by problems, which is nothing but that which concerns the individual, his family or the physician, or all of them, and at times there will be nuisances while at other times, there will be diseases, and mil in other instances, all of them will co-exist. It is known that the impact of a health problem on an individual affects not only himself, but also his surroundings. In turn, the environment around this individual can act as the origin or perpetuator of the crisis, or else serve to help in solving the conflict. Distinct tools serve the purpose of knowing the context in which health crisis is developed, such as: genogram, individual and family vital cycle. Every time two people communicate, the agreement or disagreement generate possible variables. In the physician-patient relationship, this is no exception. Values, beliefs, feelings, and information of each individual different and physicians not necessarily in agreement in several issues during a visit. The objective is the need to achieve a minimum of agreements so that this visit has therapeutic effectiveness, thus being if/rpm -taw to find a common territory. Relations in general involve power; care, feelings, trust and goals. The objective in this type of relationship must be obviously shared ly both and cannot be any other than that of achieving, the highest level of health to our patient. So, our specialty, considered of low complexity, becomes a highly cognitive complexity, special and there is no doubt that it is a lot easier to handle

  19. Phase gratings for plasmon focusing

    Offerhaus, H.L.; Bergen, van den, GJA Gino; Hulst, van, N.F.

    2005-01-01

    We report gratings structures realized for the creation of focused plasmons through noncollinear phasematching. The gratings are created on gold by focused ion beam milling and the plasmons were measured using phase sensitive photon scanning tunneling microscope (PSTM).

  20. Focusators for laser-branding

    Doskolovich, L. L.; Kazanskiy, N. L.; Kharitonov, S. I.; Uspleniev, G. V.

    A new method is investigated for synthesis of computer-generated optical elements: focusators that are able to focus the radial-symmetrical laser beam into complex focal contours, in particular into alphanumeric symbols. The method is based on decomposition of the focal contour into segments of straight lines and semi-circles, following corresponding spacing out of the focusator on elementary segments (concentric rings or sectors) and solution of the inverse task of focusing from focusator segments into corresponding elements of the focal contour. The results of numerical computing of the field from synthesized focusators into the letters are presented. The theoretical efficiency of the focusators discussed is no less than 85%. The amplitude masks and the results of operational studies of synthesized focusators are presented.

  1. Discrete and modal focusing effects: principles and applications

    Stamate, Eugen

    2012-01-01

    the charges to distinct locations on the electrode surface depending on the entrance coordinates at the sheath edge. Two focusing effects are identified. Discrete focusing leads to the formation of a passive surface of no ion impact, near the edge of the electrodes interfacing insulators. Modal...

  2. Investigating Form-Focused Instruction.

    Ellis, Rod

    2001-01-01

    Provides an historical sketch of form-focused instruction research, defines what is meant by form-focused instruction, and discusses the main research methods that have been used to investigate form-focused instruction in terms of a broad distinction between confirmatory and interpretive research. (Author/VWL)

  3. Process-focused Salary System

    MEI Shao-zu; LI Wei

    2002-01-01

    Salary often acts as the main incentive by managers to push employees to adjust their behaviors so as to realize organization's goal. With the transfer from function-focused organization to proeess-focused organization, the new relative salary system should be established at the same time. This article is intended to introduce an original salary system-process-focused salary system. After pointing out faults of traditional function-focused salary system, the article explains the design thoughts behind the new process-focused salary system, summaries its three styles: based-on-cost, based-on-quality and based-on-task; and at last defines its application scope.

  4. The Use of Online Focus Groups to Design an Online Food Safety Education Intervention

    Mayer, Ashley Bramlett; Harrison, Judy A.

    2012-01-01

    In the development of an online food safety education intervention for college students, online focus groups were used to determine the appropriate format and messages. Focus groups are often used in qualitative research and formative evaluation of public health programs, yet traditional focus groups can be both difficult and expensive to…

  5. EDITORIAL: Focus on Cloud Physics FOCUS ON CLOUD PHYSICS

    Falkovich, Gregory; Malinowski, Szymon P.

    2008-07-01

    Cloud physics has for a long time been an important segment of atmospheric science. It is common knowledge that clouds are crucial for our understanding of weather and climate. Clouds are also interesting by themselves (not to mention that they are beautiful). Complexity is hidden behind the common picture of these beautiful and interesting objects. The typical school textbook definition that a cloud is 'a set of droplets or particles suspended in the atmosphere' is not adequate. Clouds are complicated phenomena in which dynamics, turbulence, microphysics, thermodynamics and radiative transfer interact on a wide range of scales, from sub-micron to kilometres. Some of these interactions are subtle and others are more straightforward. Large and small-scale motions lead to activation of cloud condensation nuclei, condensational growth and collisions; small changes in composition and concentration of atmospheric aerosol lead to significant differences in radiative properties of the clouds and influence rainfall formation. It is justified to look at a cloud as a composite, nonlinear system which involves many interactions and feedback. This system is actively linked into a web of atmospheric, oceanic and even cosmic interactions. Due to the complexity of the cloud system, present-day descriptions of clouds suffer from simplifications, inadequate parameterizations, and omissions. Sometimes the most fundamental physics hidden behind these simplifications and parameterizations is not known, and a wide scope of view can sometimes prevent a 'microscopic', deep insight into the detail. Only the expertise offered by scientists focused on particular elementary processes involved in this complicated pattern of interactions allows us to shape elements of the puzzle from which a general picture of clouds can be created. To be useful, every element of the puzzle must be shaped precisely. This often creates problems in communication between the sciences responsible for shaping

  6. Discussion on Form Focused Instruction

    冯滢

    2007-01-01

    The pedagogy of language teaching has moved from one extreme-Grammar Translation Method to the other-Communicative Language Teaching.Today Form Focused Instruction(FFI)has emerged,intending to bring language forms instructionback to the communicative language classroom.Despite of the approval of this new approach,there is a hot dispute on its two types of application:Focus on Form or Focus on FormS.This article briefly analyzes FFI in recent research studies with focus on the choice between the two types of application.The tentative conclusion is FFI does show some explicit and reliable effects on accuracy and error elimination in language teaching;however,the investigation into its application is not simply either Focus on Form Or Focus on FormS,but focuses on the optimal combination of the two in teaching.

  7. Focus

    2004-01-01

    400 Million People Shake off PovertyUN World Food Program (WFP) Executive Director James Morris recently praised the Chinese government, saying, "China has lifted several hundred million people out of poverty in less than a generation. That is an extraordinary achievement." Morris congratulated the Chinese government on its "remarkable success," adding that

  8. Focus

    2005-01-01

    Personal Information Protection Law Under Legislative Procedure;China's Most Populous Province;New Marriage Law Brings New Trends;Beijing Repeals Regulations Governing Migrant Workers;A New Law to Regulate Electrical Junk in China;Highly-educated Jobless;Growing Up Alone;Internet Gambling Invades the Chinese Mainland;Dreams of Stardom;Chinese Smokers Consume1/3 of the World's Cigarettes.

  9. Focus

    2004-01-01

    China has launched a crackdown on Internet pornography. Of China's Netizens, 70 percent are students and 20 percent are juveniles. According to conservative estimates, 46 percent of juvenile Netizens visit porn websites.

  10. Focus

    2002-01-01

    Non-public Owned Enterprises Burgeon Recently the All-China Federation of Industry and Commerce published the results of its member enterprise 2001 survey. According to survey statistics, the total business income of

  11. Focus

    2002-01-01

    The Chinese railway department has decided to make significant adjustments to its railway network.It is tobuild a second Beijing-Guangzhou Railway line exclusively for passenger transport.The new railway,over2.000kilometers long,will take only 10hours to cover the distance between Beijing and Guangzhou.The

  12. FOCUS

    2005-01-01

    More than 600 Posionous Trees Found in Hainan;Cyber Counseling Service for Prisoners;""Super"" Maize Bred in China;English Level Improves as Proficiency in Mother Tongue Declines;Greater Proportion oF Chinese Leaders Graduates in Liberal Arts.

  13. Tea aroma formation

    Chi-Tang Ho

    2015-03-01

    Full Text Available Besides water, tea is one of the most popular beverages around the world. The chemical ingredients and biological activities of tea have been summarized recently. The current review summarizes tea aroma compounds and their formation in green, black, and oolong tea. The flavor of tea can be divided into two categories: taste (non-volatile compounds and aroma (volatile compounds. All of these aroma molecules are generated from carotenoids, lipids, glycosides, etc. precursors, and also from Maillard reaction. In the current review, we focus on the formation mechanism of main aromas during the tea manufacturing process.

  14. Pharmacometrics: Focus on the Patient

    Dumitrescu, T Pene; Fossler, MJ; Schmith, VD

    2015-01-01

    Pharmacometrics, whether using simple or complex models, has contributed to rational and efficient drug development,1–3 with the main focus on early drug development.4 This article describes why opportunities more directly focused on the patient abound in late stage development, illustrating the concept with three innovative examples which focus on benefits to patients, enabling drugs that are truly efficacious to reach the market faster in diseases with high unmet medical needs, while maintaining adequate safety. PMID:26225220

  15. Highly focused supersonic microjets: numerical simulations

    Peters, Ivo R; Oudalov, Nikolai; Sun, Chao; Prosperetti, Andrea; Lohse, Detlef; van der Meer, Devaraj

    2012-01-01

    By focusing a laser pulse inside a capillary partially filled with liquid, a vapour bubble is created which emits a pressure wave. This pressure wave travels through the liquid and creates a fast, focused axisymmetric microjet when it is reflected at the meniscus. We numerically investigate the formation of this microjet using axisymmetric boundary-integral simulations, where we model the pressure wave as a pressure pulse applied on the bubble. We find a good agreement between the simulations and experimental results in terms of the time evolution of the jet and on all parameters that can be compared directly. We present a simple analytical model that accurately predicts the velocity of the jet after the pressure pulse and its maximum velocity.

  16. Bulge Formation

    Combes, F

    1999-01-01

    The currently discussed theories of bulge formation are reviewed, including the primordial scenario, where bulges form rapidly and then accrete disks, the secular scenario, where bulges are formed by dynamical evolution of disks through bars and galaxy interactions, and some combinations of both, where formation of bulges and disks are more continuous and interleaved. The various scenarios make specific predictions about the relative masses, angular momenta, colours, metallicities of bulges relative to disks, and the bulge-to-disk ratio as a function of time. Dynamical processes relevant to the formation of bulges (bar instabilities, mergers) are described and tested against observed statistics. Current data suggest a dynamical feedback from gravitational instabilities in bulge and disk formation. It is very difficult to discriminate between the various scenarios from surveys at z=0 only, and observations at high redshift are presently the best hope for large progress.

  17. Focusing on life beyond numers

    Prip, Anne; Christiansen, Anette Wendelboe; Zoffmann, Vibeke

    2014-01-01

    home to clarify their difficulties. Shifting the focus from ‘numbers’ to the patients’ life with diabetes can increase attendance and release the potential for change. Conclusion Susan benefitted from this flexible intervention, breaking out of her isolation by focusing on what was personally important...

  18. CTE's Focus on Continuous Improvement

    Foster, John; Kelley, Patricia; Pritz, Sandy; Hodes, Carol

    2011-01-01

    Just one of the ways career and technical education (CTE) is revamping its image is through increased attention to data-driven instructional techniques as a means of improving and focusing instruction on what matters most. Accountability and data have increasingly become a core focus of research, news, and commentary about education in recent…

  19. Doing Focus-on-Form.

    Ellis, Rod; Basturkmen, Helen; Loewen, Shawn

    2002-01-01

    Considers the rationale for using a focus on form approach to teaching form as opposed to the more traditional focus on forms approach where linguistic features are treated sequentially. Describes methodological options for attending to form in communication. (Author/VWL)

  20. Aerial camera auto focusing system

    Wang, Xuan; Lan, Gongpu; Gao, Xiaodong; Liang, Wei

    2012-10-01

    Before the aerial photographic task, the cameras focusing work should be performed at first to compensate the defocus caused by the changes of the temperature, pressure etc. A new method of aerial camera auto focusing is proposed through traditional photoelectric self-collimation combined with image processing method. Firstly, the basic principles of optical self-collimation and image processing are introduced. Secondly, the limitations of the two are illustrated and the benefits of the new method are detailed. Then the basic principle, the system composition and the implementation of this new method are presented. Finally, the data collection platform is set up reasonably and the focus evaluation function curve is draw. The results showed that: the method can be used in the Aerial camera focusing field, adapt to the aviation equipment trends of miniaturization and lightweight .This paper is helpful to the further work of accurate and automatic focusing.

  1. Six beam spherical compression of plasma focus guns

    A preliminary experiment with a one beam plasma focus is carried out to confirm plasma formation with the lowest input energy of 0.2 kJ for six beam spherical compression of plasma focus guns. The plasma front of this cableless gun can be used for compression and for the coupling of six guns situated along three rectangular axes, providing a good plasma focus pinch instantaneously or many plasma focus pinches continuously. The whole device with the energy bank is mounted on a sphere, and the minimum requirement for the plasma chamber of this sphere is a diameter of ∼ 22 cm. (author). 4 refs, 3 figs

  2. CDP: application of focus drilling

    Geisler, S.; Bauer, J.; Haak, U.; Schulz, K.; Old, G.; Matthus, E.

    2009-01-01

    The achievement of a depth of focus required for stable process conditions is one of the biggest challenges in modern optical photolithography. There are several ways of improving the depth of focus. For line/space layers, for instance, application of RET (Resolution Enhancement Technology) using scattering bars, phaseshift masks or optimized illumination systems have shown good results. For contact and via layers the depth of focus is limited and critical, due to the structure size of the holes, alternating pattern density and wafer topology. A well known method of improving the depth of focus for contact and via layers is called focus latitude enhancement exposure (FLEX) [1-3]. With FLEX, several focal planes are being exposed, i.e. each during a separate exposure step. The main drawback is low throughput, as the total processing time rises which each additional exposure. In this paper, we investigate Nikon's CDP (continuous depth of focus expansion procedure) [4]. The CDP option is applicable to modern scanning exposure tools [4-5]. A schematic view of the procedure is shown in Fig. 1. The CDP value or CDP amplitude defines the tilt of the wafer and thus the range of focus in the resist, as the focus plane migrates through the resist during the exposure. The main advantage of CDP, compared to FLEX, is higher throughput, since focal planes are defined within a single exposure. A non-CDP exposure may result in varying aerial images within resist thickness, therefore leading to decreased image contrast within out-of-focus planes. As shown in Fig. 1 the averaged aerial images of a CDP exposure induce better image contrast throughout the resist layer and therefore increase the focus window.

  3. Microsources of intense fusion in focused discharges of plasma focus

    High nuclear reactivity within submillimetric domains in the space structure of the pinch of focused discharges has been reported since many years. Now the authors summarize and compare new and previously published data from our experiments which describe the emission of D+ beams and the occurrence of nuclear fusion reactions within submillimetric domains of plasma focus (PF) discharges for W = 5--10 kJ PF machines operating in the neutron optimized mode

  4. New Results from the FOCUS/E831 Experiment

    Kim, D Y; Alimonti, G; Anjos, J C; Arena, V; Barberis, S; Bediaga, I; Benussi, L; Bertani, L; Bianco, S; Boca, G; Bonomi, G; Boschini, M; Butler, J N; Carrillo, S; Casimiro, E; Cawlfield, C; Cerutti, A; Cheung, H W K; Chiodini, G; Cho, K; Chung, Y S; Cinquini, L; Cuautle, E; Cumalat, J P; D'Angelo, P; Davenport, T F; De Miranda, J M; Di Corato, M; Dini, P; Dos Reis, A C; Edera, L; Engh, D; Erba, S; Fabbri, Franco Luigi; Gaines, I; Garbincius, P H; Gardner, R; Garren, L A; Giammarchi, M; Gianini, G; Gottschalk, E E; Green, S W; Göbel, C; Han, T; Hernández, H; Hosack, M; Inzani, P; Johns, W E; Kang, J S; Kasper, P H; Kim, D Y; Ko, B R; Kreymer, A E; Kryemadhi, A; Kutschke, R; Kwak, J W; Lee, K B; Leveraro, F; Liguori, G; Link, J M; Lopes-Pegna, D; Luiggi, E; López, A M; Magnin, J; Malvezzi, S; Massafferri, A; Menasce, D; Merlo, M M; Mezzadri, M; Mitchell, R; Moroni, L; Méndez, H; Nehring, M S; O'Reilly, B; Pantea, D; Paris, A; Park, H; Pedrini, D; Pepe, I M; Polycarpo, E; Pon, C; Prelz, F; Quinones, J; Rahimi, A; Ramírez, J E; Ratti, S P; Reyes, M; Riccardi, C; Rovere, M; Sala, S; Segoni, I; Sheaff, M; Sheldon, P D; Stenson, K; Sánchez-Hernández, A; Uribe, C; Vaandering, E W; Vitulo, P; Vázquez, F; Wahl, M; Wang, M; Webster, M; Wilson, J R; Wiss, J; Yager, P M; Zallo, A; Zhang, Y; Kim, Doris Yangsoo

    2003-01-01

    The E831/FOCUS experiment at Fermilab is a photoproduction experiment which generated high quality charm particles. During its run, we obtained a large data set, including more than 1 million charm mesons in the Kpi/K2pi/K3pi mode decays. The current analysis efforts by the collaboration members are quite active and diverse. I will summarize the recent papers published by the FOCUS group on topics of semileptonic decays of charm mesons.

  5. Plutonium focus area: Technology summary

    To ensure research and development programs focus on the most pressing environmental restoration and waste management problems at the U.S. Department of Energy (DOE), the Assistant Secretary for the Office of Environmental Management (EM) established a working group in August 1993 to implement a new approach to research and technology development. As part of this approach, EM developed a management structure and principles that led to creation of specific focus areas. These organizations were designed to focus scientific and technical talent throughout DOE and the national scientific community on major environmental restoration and waste management problems facing DOE. The focus area approach provides the framework for inter-site cooperation and leveraging of resources on common problems. After the original establishment of five major focus areas within the Office of Technology Development (EM-50), the Nuclear Materials Stabilization Task Group (NMSTG, EM-66) followed EM-50's structure and chartered the Plutonium Focus Area (PFA). NMSTG's charter to the PFA, described in detail later in this book, plays a major role in meeting the EM-66 commitments to the Defense Nuclear Facilities Safety Board (DNFSB). The PFA is a new program for FY96 and as such, the primary focus of revision 0 of this Technology Summary is an introduction to the Focus Area; its history, development, and management structure, including summaries of selected technologies being developed. Revision 1 to the Plutonium Focus Area Technology Summary is slated to include details on all technologies being developed, and is currently planned for release in August 1996. The following report outlines the scope and mission of the Office of Environmental Management, EM-60, and EM-66 organizations as related to the PFA organizational structure

  6. Individual focus and knowledge contribution

    Adamic, Lada A; Yang, Jiang; Gerrish, Sean; Nam, Kevin K; Clarkson, Gavin S

    2010-01-01

    Before contributing new knowledge, individuals must attain requisite background knowledge or skills through schooling, training, practice, and experience. Given limited time, individuals often choose either to focus on few areas, where they build deep expertise, or to delve less deeply and distribute their attention and efforts across several areas. In this paper we measure the relationship between the narrowness of focus and the quality of contribution across a range of both traditional and recent knowledge sharing media, including scholarly articles, patents, Wikipedia, and online question and answer forums. Across all systems, we observe a small but significant positive correlation between focus and quality.

  7. String Formatting Considered Harmful for Novice Programmers

    Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

    2010-01-01

    In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found that 8% of all the…

  8. Galaxy Formation

    Sparre, Martin

    Galaxy formation is an enormously complex discipline due to the many physical processes that play a role in shaping galaxies. The objective of this thesis is to study galaxy formation with two different approaches: First, numerical simulations are used to study the structure of dark matter and how...... galaxies form stars throughout the history of the Universe, and secondly it is shown that observations of gamma-ray bursts (GRBs) can be used to probe galaxies with active star formation in the early Universe. A conclusion from the hydrodynamical simulations is that the galaxies from the stateof...... important, since it helps constraining chemical evolution models at high redshift. A new project studying how the population of galaxies hosting GRBs relate to other galaxy population is outlined in the conclusion of this thesis. The core of this project will be to quantify how the stellar mass function of...

  9. Wayside Teaching: Focusing on Relationships

    Powell, Sara Davis

    2011-01-01

    Wayside teaching focuses on building and maintaining positive relationships with students. Teachers can implement certain wayside teaching practices to end the year in a positive way and begin preparing for the next school year.

  10. Instrument Measures Shift In Focus

    Steimle, Lawrence J.

    1992-01-01

    Optical components tested at wavelengths from ultraviolet to infrared. Focus-shift-measuring instrument easy to use. Operated in lighted room, without having to make delicate adjustments while peering through microscope. Measures distance along which focal point of converging beam of light shifted by introduction of nominally plane parallel optical component into beam. Intended primarily for measuring focus shifts produced by windows and filters at wavelengths from 120 to 1,100 nanometers. Portable, compact, and relatively inexpensive for degree of precision.

  11. Individual focus and knowledge contribution

    Adamic, Lada A.; Wei, Xiao; Yang, Jiang; Gerrish, Sean; Nam, Kevin K.; Clarkson, Gavin S.

    2010-01-01

    Before contributing new knowledge, individuals must attain requisite background knowledge or skills through schooling, training, practice, and experience. Given limited time, individuals often choose either to focus on few areas, where they build deep expertise, or to delve less deeply and distribute their attention and efforts across several areas. In this paper we measure the relationship between the narrowness of focus and the quality of contribution across a range of both traditional and ...

  12. Properties of self-focusing of elliptic beams

    Stationary self-focusing of collimated elliptic Gaussian beams is studied numerically. It is shown that the critical self-focusing power increases with increasing the axial ratio of the initial elliptic cross section. Self-focusing is accompanied by oscillations of the beam transverse size caused by the competition between the diffraction-limited divergence and nonlinear compression. As the power of the beam with the axial ratio a/b≥3 increases, aberration self-focusing occurs, at which, after the formation and competition of several intensity maxima in the beam cross section, a global maximum appears at the beam centre, which forms a nonlinear focus. The approximation formula for the self-focusing distance is generalised to elliptic beams. (nonlinear optical phenomena)

  13. Sausage instability threshold in a low energy plasma focus

    Development of sausage instability (m = 0 mode) is studied in a small low energy Mather-type plasma focus. A shadow graphic study of the current sheath has shown that the focused plasma necks off during the radial phase before the maximum compression. This may indicate the lowering of the instability threshold. Three hook-type structures are observed which may not be due to the multifoci formation. The bubble shape structure is observed to be developed in the expansion phase. (author)

  14. Prime Focus Instrument of Prime Focus Spectrograph for Subaru Telescope

    Wang, Shiang-Yu; Schwochert, Mark A; Huang, Pin-Jie; Kimura, Masahiko; Chen, Hsin-Yo; Reiley, Dan J; Mao, Peter; Fisher, Charles D; Tamura, Naoyuki; Chang, Yin-Chang; Hu, Yen-Sang; Ling, Hung-Hsu; Wen, Chih-Yi; Chou, Richard C -Y; Takato, Naruhisa; Sugai, Hajime; Ohyama, Youichi; Karoji, Hiroshi; Shimono, Atsushi; Ueda, Akitoshi

    2014-01-01

    The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph design for the prime focus of the 8.2m Subaru telescope. PFS will cover 1.3 degree diameter field with 2394 fibers to complement the imaging capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners are located. In addition, the acquisition and guiding (A&G) cameras, the optical fiber positioner system, the cable wrapper, the fiducial fibers, illuminator, and viewer, the field element, and the telemetry system are located inside the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match those of the HSC Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy.

  15. Reflectors to Focus Wave Energy

    Kramer, Morten; Frigaard, Peter

    2005-01-01

    Wave Energy Converters (WEC’s) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased by approximately 30......-50%. Clearly longer wave reflectors will focus more wave energy than shorter wave reflectors. Thus the draw back is the increased wave forces for the longer wave reflectors. In the paper a procedure for calculating the energy efficiency and the wave forces on the reflectors are described, this by use of a 3D...

  16. Speeding chemical reactions by focusing

    Lacasta, A. M.; Ramírez-Piscina, L.; Sancho, J. M.; Lindenberg, K.

    2013-04-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, and obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate ˜t-1/2 to very close to the perfect mixing rate, ˜t-1.

  17. Speeding chemical reactions by focusing

    Lacasta, A M; Sancho, J M; Lindenberg, K

    2012-01-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  18. Focused bedside ultrasonography by clinicians

    Hillingsø, Jens; Svendsen, Lars Bo; Nielsen, Michael Bachmann

    2008-01-01

    behaviour and course compliance. MATERIAL AND METHODS: The course consisted of a combined didactic, hands-on, one-day course including a skills test and a review of 20 still-pictures of pathological findings for final authorization. A questionnaire focusing on pre- and post-course activity and its impact on...

  19. Focus group report, Part I

    The Waste Policy Institute, through a cooperative agreement with the U.S. Department of Energy's (DOE) Office of Science and Technology (OST), conducted two focus groups with people who live or work near DOE sites. The purpose of the focus groups was to gain a better understanding of the general community's information needs about the development of innovative technologies that are used in the cleanup of the sites. The authors wanted to better understand of what role these people want to play in the development of new technologies, how OST communication products can help facilitate that role, and the usefulness of current OST communication products. WPI held the focus groups in communities near the Idaho National Engineering and Environmental Laboratory (INEEL) and the Savannah River Site (SRS) because they are among the DOE sites that cannot be cleaned up before 2006. To include many facets of the communities, WPI randomly selected participants from membership lists of organized groups in each community including: elected officials, school boards, unions, chambers of commerce, economic development organizations, environmental organizations, health and human service organizations, and area clergy. While in the communities, WPI also interviewed stakeholders such as tribal representatives and a Citizens Advisory Board (CAB) member. Qualitative data gathered during the focus group sessions give some indication of general stakeholder opinions. However, the authors caution readers not to make broad assumptions about the general stakeholder audience based on the opinions of a limited number of general community stakeholders

  20. Focus groups in organizational research

    L. Kamfer

    1989-05-01

    Full Text Available Focus groups are commonly used in marketing research. In this article an application of the focus group technique within an organizational context is described. Nine focus groups were conducted during the planning stage of a survey intended to establish employee perceptions of advancement policies and practices in a major South African manufacturing company. Fourteen themes emerged from a content analysis of the discussions. Two of these reflected aspects requiring commitment decisions from management toward the survey. The others indicated areas of concern which should be included in the survey. In this way, the focus groups contributed useful information for the subsequent sample survey. Opsomming Fokusgroepe word algemeen in bemarkingsnavorsing aangewend. In hierdie studie word 'n toepassingvan die fokusgroeptegniek in die konteks van 'n opname binne 'n organisasie beskryf. Nege fokusgroepbesprekings is gevoer tydens die beplanningstadium van 'n opname wat binne 'n Suid-Afrikaanse vervaardigingsonderneming gedoen is. Die doel van die opname was om die persepsies van werknemers teenoor die bestaande personeel- en bestuursontwikkelingsbeleid en -praktyke van die maatskappy te bepaal. Veertien temas is deur middel van 'n inhoudontleding gei'dentifiseer. Twee hiervan het aspekte aangedui waaroor bestuur beginselbesluite t.o.v. die opname sou moes neem. Die ander het probleemareas aangedui wat by die ondersoek selfingesluit behoort te word. Sodoende het die fokusgroepe inligting verskafwat vir die latere vraelysopname belangrik was.

  1. Math Fair: Focus on Fractions

    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,…

  2. Zoonotic Focus of Plague, Algeria

    Bitam, Idir; Baziz, Belkacem; Rolain, Jean-Marc; Belkaid, Miloud; Raoult, Didier

    2006-01-01

    After an outbreak of human plague, 95 Xenopsylla cheopis fleas from Algeria were tested for Yersinia pestis with PCR methods. Nine fleas were definitively confirmed to be infected with Y. pestis biovar orientalis. Our results demonstrate the persistence of a zoonotic focus of Y. pestis in Algeria.

  3. Toward a value - focused Marketing

    M. Bîja

    2013-06-01

    Full Text Available The purpose of this article is to analyse the theory that refers to the creation of value by explaining the means of its creation, the concepts of customer’s value in order to finally focus on the concept of co-creation of value.

  4. Tsunami Amplification due to Focusing

    Moore, C. W.; Kanoglu, U.; Titov, V. V.; Aydin, B.; Spillane, M. C.; Synolakis, C. E.

    2012-12-01

    Tsunami runup measurements over the periphery of the Pacific Ocean after the devastating Great Japan tsunami of 11 March 2011 showed considerable variation in far-field and near-field impact. This variation of tsunami impact have been attributed to either directivity of the source or by local topographic effects. Directivity arguments alone, however, cannot explain the complexity of the radiated patterns in oceans with trenches and seamounts. Berry (2007, Proc. R. Soc. Lond. A 463, 3055-3071) discovered how such underwater features may concentrate tsunamis into cusped caustics and thus cause large local amplifications at specific focal points. Here, we examine focusing and local amplification, not by considering the effects of underwater diffractive lenses, but by considering the details of the dipole nature of the initial profile, and propose that certain regions of coastline are more at-risk, not simply because of directivity but because typical tsunami deformations create focal regions where abnormal tsunami wave height can be registered (Marchuk and Titov, 1989, Proc. IUGG/IOC International Tsunami Symposium, Novosibirsk, USSR). In this work, we present a new general analytical solution of the linear shallow-water wave equation for the propagation of a finite-crest-length source over a constant depth without any restriction on the initial profile. Unlike the analytical solution of Carrier and Yeh (2005, Comp. Mod. Eng. & Sci. 10(2), 113-121) which was restricted to initial conditions with Gaussian profiles and involved approximation, our solution is not only exact, but also general and allows the use of realistic initial waveform such as N-waves as defined by Tadepalli and Synolakis (1994, Proc. R. Soc. Lond. A 445, 99-112). We then verify our analytical solution for several typical wave profiles, both with the NOAA tsunami forecast model MOST (Titov and Synolakis, 1998, J. Waterw. Port Coast. Ocean Eng. 124(4), 157-171) which is validated and verified through

  5. Digital reverse propagation in focusing Kerr media

    Lenses allow the formation of clear images in homogeneous linear media. Holography is an alternative imaging method, but its use is limited to cases in which it provides an advantage, such as three-dimensional imaging. In nonlinear media, lenses no longer work. The light produces intensity-dependent aberrations. The reverse propagation method used in digital holography to form images from recorded holograms works even in Kerr media [M. Tsang, D. Psaltis, and F. G. Omenetto, Opt. Lett. 28, 1873 (2003).]. The principle has been experimentally demonstrated recently in defocusing media [C. Barsi, W.Wan, and J.W. Fleischer, Nat. Photonics 3, 211 (2009).]. Here, we report experimental results in focusing media.

  6. Formation of multiple networks

    Magnani, Matteo; Rossi, Luca

    2013-01-01

    While most research in Social Network Analysis has focused on single networks, the availability of complex on-line data about individuals and their mutual heterogenous connections has recently determined a renewed interest in multi-layer network analysis. To the best of our knowledge, in this paper...... we introduce the first network formation model for multiple networks. Network formation models are among the most popular tools in traditional network studies, because of both their practical and theoretical impact. However, existing models are not sufficient to describe the generation of multiple...... networks. Our model, motivated by an empirical analysis of real multi-layered network data, is a conservative extension of single-network models and emphasizes the additional level of complexity that we experience when we move from a single- to a more complete and realistic multi-network context....

  7. Injector for RFQ using electrostatically focused transport and matching

    We discuss the principles and performance of a new type of high- current H- injector for RFQs. The distinguishing feature of our injector is that we replace the conventional gas-neutralized transport and matching units by electrostatic focusing units. Our system prevents plasma formation along the beam instead of utilizing it. Some advantages of this approach are discussed. 13 refs., 6 figs

  8. Formation of Bidisperse Particle Clouds

    Er, Jenn Wei; Zhao, Bing; Law, Adrian W. K.; Adams, E. Eric

    2014-11-01

    When a group of dense particles is released instantaneously into water, their motion has been conceptualized as a circulating particle thermal (Ruggerber 2000). However, Wen and Nacamuli (1996) observed the formation of particle clumps characterized by a narrow, fast moving core shedding particles into wakes. They observed the clump formation even for particles in the non-cohesive range as long as the source Rayleigh number was large (Ra > 1E3) or equivalently the source cloud number (Nc) was small (Nc < 3.2E2). This physical phenomenon has been investigated by Zhao et al. (2014) through physical experiments. They proposed the theoretical support for Nc dependence and categorized the formation processes into cloud formation, transitional regime and clump formation. Previous works focused mainly on the behavior of monodisperse particles. The present study further extends the experimental investigation to the formation process of bidisperse particles. Experiments are conducted in a glass tank with a water depth of 90 cm. Finite amounts of sediments with various weight proportions between coarser and finer particles are released from a cylindrical tube. The Nc being tested ranges from 6E-3 to 9.9E-2, which covers all the three formation regimes. The experimental results showed that the introduction of coarse particles promotes cloud formation and reduce the losses of finer particles into the wake. More quantitative descriptions of the effects of source conditions on the formation processes will be presented during the conference.

  9. Cement Formation

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten;

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including an...... overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid...

  10. Plasma focusing in coaxial gun

    A capacitor bank has been discharged between two coaxial electrodes of 6.6 cm outer diameter, 3.2 cm inner diameter and length of 31.5 cm. filled with hydrogen gas at pressure of 310 μHg. Results show that, the axial and radial plasma current reach a maximum value at a position adjacent to the gun muzzle, at which the plasma focus occurs. The measurement of the electron temperature and density and azimuthal electric field along the axis of the expansion chamber, gives a maximum value at z∼18 cm from the gun muzzle, while the axial plasma current and velocity has a minimum value at that position. These results indicate that a second point of a plasma focus has been formed at z∼18 cm from the gun muzzle, along the axis of the expansion chamber

  11. Focus on astronomical predictable events

    Jacobsen, Aase Roland

    2006-01-01

    At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...... the public and makes a point of interest in a small exhibit area. A countdown clock can be simple, but it is possible to expand the concept to an eye-catching part of a museum.......At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...

  12. Methodology of focus group research

    Đurić Slađana

    2005-01-01

    Full Text Available The popularity of focus group interview has rapidly grown in the last two decades. After long-time period in which this technique had been practiced almost exclusively in marketing research it begins the period of its frequent application in a great number of academic fields (sociology, psychology, evaluation research, public opinion research, communication, medical care. Only with the intensification of investigations in which focus group interviewing has been applied it was enabled achieving of experience that can be methodologically generalized, with accompanying development of the technique. This text refers to the basic methodological principles of this technique's application. In the paper the methodological experiences are synthesized which are accumulated through an enormous number of foreign explorations, as well as in many-year research experience of the author.

  13. Focusing Telescopes in Nuclear Astrophysics

    Ballmoos, Peter von

    2007-01-01

    This volume is the first of its kind on focusing gamma-ray telescopes. Forty-eight refereed papers provide a comprehensive overview of the scientific potential and technical challenges of this nascent tool for nuclear astrophysics. The book features articles dealing with pivotal technologies such as grazing incident mirrors, multilayer coatings, Laue- and Fresnel-lenses - and even an optic using the curvature of space-time. The volume also presents an overview of detectors matching the ambitious objectives of gamma ray optics, and facilities for operating such systems on the ground and in space. The extraordinary scientific potential of focusing gamma-ray telescopes for the study of the most powerful sources and the most violent events in the Universe is emphasized in a series of introductory articles. Practicing professionals, and students interested in experimental high-energy astrophysics, will find this book a useful reference

  14. Focusing of truncated Gaussian beams

    Horváth, Zoltán L.; Bor, Zsolt

    2003-07-01

    It is shown that the focusing of truncated Gaussian beams can be treated by the same manner as uniform spherical waves, i.e., the diffraction integral can be expressed by the Lommel functions, which offers a very efficient way for the calculation of the three-dimensional light distribution near focus. All the expressions for the uniform spherical waves hold good for Gaussian beams if the first variable in the Lommel functions is extended to the complex domain. The intensity distribution depending on the Fresnel number and the truncation coefficient is calculated. The location of the first few minima and maxima of the intensity in focal plane is given for different values of the truncation coefficient. The phase behavior depending on the truncation coefficient is studied.

  15. EDITORIAL: Focus on terahertz plasmonics

    Rahm, Marco; Nahata, Ajay; Akalin, Tahsin; Beruete, Miguel; Sorolla, Mario

    2015-10-01

    Plasmonics is one of the growing fields in modern photonics that has garnered increasing interest over the last few years. In this focus issue, the specific challenges concerning terahertz plasmonics have been addressed and most recent advances in this specific field have been highlighted. The articles demonstrate the diversity and the opportunities of this rich field by covering a variety of topics ranging from the propagation of surface plasmon polaritons (SPPs) on artificially structures surfaces, 2D manipulation of surface plasmons and SPPs, plasmonic focusing, plasmonic high-Q resonators for sensing applications, plasmonically enhanced terahertz antennas to terahertz field manipulation by use of plasmonic structures. The articles substantiate the impact of plasmonics and its great innovative potential for terahertz technology. In memory of Professor Mario Sorolla Ayza.

  16. Micromachining using focused ion beams

    Focused ion beam (FIB) systems prove to be useful precision micromachining tools for a wide variety of applications. This micromachining technique includes scanning ion microscopy (SIM), micromachining by physical sputtering, and the ion-beam induced surface chemistry for etching and deposition. This technique is applied to image and modify IC's, to micromechanical applications, to modify the tip shape of tungsten emitters, and to prepare cross sections of selected regions for inspection in a transmission electron microscope (TEM). (orig.)

  17. Cherenkov particle identification in FOCUS

    Link, J M; Alimonti, G; Anjos, J C; Arena, V; Bediaga, I; Bianco, S; Boca, G; Bonomi, G; Boschini, M; Butler, J N; Carrillo, S; Casimiro, E; Cawlfield, C; Cheung, H W K; Cho, K; Chung, Y S; Cinquini, L; Cuautle, E; Cumalat, J P; D'Angelo, P; Di Corato, M; Dini, P; Engh, D; Fabbri, Franco Luigi; Gaines, I; Garbincius, P H; Gardner, R; Garren, L A; Giammarchi, M; Gianini, G; Gottschalk, E; Göbel, C; Handler, T; Hernández, H; Hosack, M; Inzani, P; Johns, W E; Kang, J S; Kasper, P H; Kim, D Y; Ko, B R; Kreymer, A E; Kryemadhi, A; Kutschke, R; Kwak, J W; Lee, K B; Leveraro, F; Liguori, G; Magnin, J; Malvezzi, S; Massafferri, A; Menasce, D; Merlo, M M; Mezzadri, M; Milazzo, L; Miranda, J M D; Mitchell, R; Montiel, E; Moroni, L; Méndez, H; Méndez, L; Nehring, M S; O'Reilly, B; Olaya, D; Pantea, D; Paris, A; Park, H; Park, K S; Pedrini, D; Pepe, I M; Pontoglio, C; Prelz, F; Quinones, J; Rahimi, A; Ramírez, J E; Ratti, S P; Reis, A C D; Reyes, M; Riccardi, C; Rivera, C; Rovere, M; Sala, S; Sarwar, S; Segoni, I; Sheaff, M; Sheldon, P D; Stenson, K; Sánchez-Hernández, A; Uribe, C; Vaandering, E W; Vitulo, P; Vázquez, F; Webster, M; Wilson, J R; Wiss, J; Xiong, W; Yager, P M; Zallo, A; Zhang, Y

    2002-01-01

    We describe the algorithm used to identify charged tracks in the fixed-target charm-photoproduction experiment FOCUS. We begin by describing the new algorithm and contrast this approach with that used in our preceding experiment - E687. We next illustrate the algorithm's performance using physics signals. Finally, we briefly describe some of the methods used to monitor the quantum efficiency and noise of the Cherenkov cells.

  18. Optimum Design of Plasma Focus

    The optimum design of Plasma Focus devices is presented based in a lumped parameter model of the MHD equations.Maps in the design parameters space are obtained, which determine the length and deuterium pressure required to produce a given neutron yield.Sensitivity analyses of the main effective numbers (sweeping efficiencies) was performed, and lately the optimum values were determined in order to set a basis for the conceptual design

  19. World Focus on the Moment

    Audrey

    2008-01-01

    @@ Chinese people would never for-get the moment-14:28, on May 12, 2008, as the 8.0-magnitude earthquake shook the whole of Sichuan; at that moment the world's at-tention was focused on the southwest of China - the homeland of the Giant Panda. This rare yet catastrophic natural disaster has resulted in the heavy loss of lives and property throughout the region.

  20. Environmental Protection: a shifting focus

    Venselaar, Jan

    2004-01-01

    The last two decades have seen a fundamental change in the way chemistry handles environmental issues. A shift in focus has occurred from 'end-of-pipe' to prevention and process integration. Presently an even more fundamental change is brought about by the need for sustainable development. It is becoming the incentive for much of the research and development in chemistry and engineering. Visions and approaches on the role of chemistry and the way chemistry is done, change. New knowledge is co...

  1. Focus group report - part II

    The Waste Policy Institute, through a cooperative agreement with the U.S. Department of Energy (DOE) Office of Science and Technology (OST) conducted a focus group with members of the Hanford Advisory Board (HAB), interviews with tribal government representatives, and a survey of Oak Ridge Local Oversight Committee (LOC) and Site Specific Advisory Board (SSAB) members. The purpose was to understand what members of the interested and involved public want to know about technology development and ways to get that information to them. These data collection activities were used as a follow-up to two previously held focus groups with the general public near Idaho National Engineering and Environmental Laboratory (INEEL) and the Savannah River Site (SRS). Most participants from the first two focus groups said they did not have time and/or were not interested in participating in technology decision-making. They said they would prefer to defer to members of their communities who are interested and want to be involved in technology decision-making

  2. Focus On Photoshop Elements Focus on the Fundamentals

    Asch, David

    2011-01-01

    Are you bewildered by the advanced editing options available in Photoshop Elements? Do you want to get the most out of your image without going bleary-eyed in front of a computer screen? This handy guide will explain the ins and outs of using Photoshop Elements, without having to spend hours staring at the screen. Using a fabulous combination of easy-to-follow advice and step-by-step instructions, Focus On Photoshop Elements gives great advice on setting up, storing and sharing your image library and teaches you the basics of RAW image processing and color correction, plus shows you how to edi

  3. The quest for customer focus.

    Gulati, Ranjay; Oldroyd, James B

    2005-04-01

    Companies have poured enormous amounts of money into customer relationship management, but in many cases the investment hasn't really paid off. That's because getting closer to customers isn't about building an information technology system. It's a learning journey-one that unfolds over four stages, requiring people and business units to coordinate in progressively more sophisticated ways. The journey begins with the creation of a companywide repository containing each interaction a customer has with the company, organized not by product, purchase, or location, but by customer. Communal coordination is what's called for at this stage, as each group contributes its information to the data pool separately from the others and then taps into it as needed. In the second stage, one-way serial coordination from centralized IT through analytical units and out to the operating units allows companies to go beyond just assembling data to drawing inferences. In stage three, companies shift their focus from past relationships to future behavior. Through symbiotic coordination, information flows back and forth between central analytic units and various organizational units like marketing, sales, and operations, as together they seek answers to questions like "How can we prevent customers from switching to a competitor?" and "Who would be most likely to buy a new product in the future"? In stage four, firms begin to move past discrete, formal initiatives and, through integral coordination, bring an increasingly sophisticated understanding oftheir customers to bear in all day-to-day operations. Skipping stages denies organizations the sure foundation they need to build a lasting customer-focused mind-set. Those that recognize this will invest their customer relationship dollars much more wisely-and will see their customer-focusing efforts pay offon the bottom line. PMID:15807042

  4. AutoFocus Framework Documentation

    Gaspar, Graça; Morgado, Luís; Neves, Pedro

    2009-01-01

    The work presented in this document is part of the project "AutoFocus: Adaptive Self-Improving Multi-Agent Systems" that is being developed at the research unit LabMAg, which objective is the implementation of multi-agent systems based on autonomous entities capable of self-optimized and adaptive behaviors. The notion of autonomic computation, like other notions that also imply pro-active computation, is based on autonomous entities that actively work to achieve their objectives and have t...

  5. Bayesian Query-Focused Summarization

    Daumé, Hal

    2009-01-01

    We present BayeSum (for ``Bayesian summarization''), a model for sentence extraction in query-focused summarization. BayeSum leverages the common case in which multiple documents are relevant to a single query. Using these documents as reinforcement for query terms, BayeSum is not afflicted by the paucity of information in short queries. We show that approximate inference in BayeSum is possible on large data sets and results in a state-of-the-art summarization system. Furthermore, we show how BayeSum can be understood as a justified query expansion technique in the language modeling for IR framework.

  6. A focus on human flourishing.

    Bunkers, Sandra Schmidt

    2010-10-01

    In this column the author focuses on the concepts of human vulnerability and human flourishing. A parable is presented highlighting the importance of now, the present, in human flourishing. A bioethical, anthropological perspective and a nursing humanbecoming perspective on human flourishing are offered. Nursing education is challenged to emphasize the nursing theories of the discipline to teach the concept of human flourishing. Parse's concept of true presence, the four postulates of humanbecoming, and the humanbecoming community change concepts illuminate a nursing theoretical understanding of human flourishing. PMID:20870999

  7. Focusing properties of mushroom microlenses

    Boriskin, A V; Benson, T; Sewell, P; Nosich, A I

    2010-01-01

    Focusing properties of a novel type photoresist microlens are studied. A specific character of the microlens is its mushroom shape. Recently it was predicted and experimentally revealed that such a lens integrated with a light-emitting diode is capable of enhancing its output efficiency and directivity. In our paper we describe the true electromagnetic performance of a mushroom lens by applying a mathematically rigorous method of boundary integral equations. Numerical results are presented for the mushroom lens illuminated with a plane E-polarized wave and include figures describing the evolution of the lens focal spot and near field maps.

  8. Geometrically focused neutral beam accelerators

    A more reliable 40 kV, 65 A power supply drain at 0.4 A/cm2, neutral-beam accelerator was developed for the Tandem Mirror Experiment (TMX). Multiple slotted aperture grids of 60% transparency are fabricated from refractory metal wires mounted to form a spherical surface. This geometrically focuses the beam by aiming individual beamlets at the center of curvature of the spherical grid (r = 3.2 m). We attain greater reliability and faster conditioning with geometrical focusing than with the previous technique of electrostatically steering beamlets to a common point. Electrostatic steering, accomplished by offsetting grid wires, is satisfactory if the offset of a beamlet is much less than the distance from the beamlet to the grids. It was found that Pierce Angle entrance grids performed better if sharper edged. A redesigned accelerator grid support structure reduced the number of ceramic-to-metal vacuum joints, and eliminated O rings between precisely aligned parts. The suppressor grid feedthrough is required to withstand a maximum voltage of 15 kV occurring during breakdown, greatly exceeding the operating voltage of 1.5 kV. Convenient fabrication and assembly techniques have been developed. Assembly of accelerators and plasma sources in a clean room appears to reduce the conditioning time. Following the successful testing of the prototype, eight 40 kV accelerators were built for TMX. Furthermore, ten 20 kV versions were built that are modifiable to 40 kV by exchanging the entrance grid

  9. Flux focusing eddy current probe

    Simpson, John W. (Inventor); Clendenin, C. Gerald (Inventor); Fulton, James P. (Inventor); Wincheski, Russell A. (Inventor); Todhunter, Ronald G. (Inventor); Namkung, Min (Inventor); Nath, Shridhar C. (Inventor)

    1997-01-01

    A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks and material loss in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil. The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. The maximum sensor output is obtained when positioned symmetrically above the crack. Hence, by obtaining the position of the maximum sensor output, it is possible to track the fault and locate the area surrounding its tip. The accuracy of tip location is enhanced by two unique features of the sensor; a very high signal-to-noise ratio of the probe's output which results in an extremely smooth signal peak across the fault, and a rapidly decaying sensor output outside a small area surrounding the crack tip which enables the region for searching to be clearly defined. Under low frequency operation, material thinning due to corrosion damage causes an incomplete shielding of the pick-up coil. The low frequency output voltage of the probe is therefore a direct indicator of the thickness of the test sample.

  10. Multiperspective Focus+Context Visualization.

    Wu, Meng-Lin; Popescu, Voicu

    2016-05-01

    Occlusions are a severe bottleneck for the visualization of large and complex datasets. Conventional images only show dataset elements to which there is a direct line of sight, which significantly limits the information bandwidth of the visualization. Multiperspective visualization is a powerful approach for alleviating occlusions to show more than what is visible from a single viewpoint. However, constructing and rendering multiperspective visualizations is challenging. We present a framework for designing multiperspective focus+context visualizations with great flexibility by manipulating the underlying camera model. The focus region viewpoint is adapted to alleviate occlusions. The framework supports multiperspective visualization in three scenarios. In a first scenario, the viewpoint is altered independently for individual image regions to avoid occlusions. In a second scenario, conventional input images are connected into a multiperspective image. In a third scenario, one or several data subsets of interest (i.e., targets) are visualized where they would be seen in the absence of occluders, as the user navigates or the targets move. The multiperspective images are rendered at interactive rates, leveraging the camera model's fast projection operation. We demonstrate the framework on terrain, urban, and molecular biology geometric datasets, as well as on volume rendered density datasets. PMID:27045911

  11. On highly focused supersonic microjets

    Tagawa, Yoshiyuki; Willem, Claas; Peters, Ivo R; van der Meer, Deveraj; Sun, Chao; Prosperetti, Andrea; Lohse, Detlef

    2011-01-01

    By focusing a laser pulse in a liquid-filled glass-microcapillary open at one end, a small mass of liquid is instantaneously vapourised. This leads to a shock wave which travels towards the concave free surface where it generates a high-speed microjet. The initial shape of the meniscus plays a dominant role in the process. The velocity of the jet can reach supersonic speeds up to 850\\,m/s while maintaining a very sharp geometry. The entire evolution of the jet is observed by high-speed recordings of up to $10^6\\,$fps. A parametric study of the jet velocity as a function of the contact angle of the liquid-glass interface, the energy absorbed by the liquid, the diameter of the capillary tube, and the distance between the laser focus and the free surface is performed, and the results are rationalised. The method could be used for needle-free injection of vaccines or drugs.

  12. Mars brine formation experiment

    Moore, Jeffrey M.; Bullock, Mark A.; Stoker, Carol R.

    1992-01-01

    Evaporites, particularly carbonates, nitrates, and sulfates, may be major sinks of volatiles scavenged from the martian atmosphere. Mars is thought to have once had a denser, warmer atmosphere that permitted the presence of liquid surface water. The conversion of atmospheric CO2 into carbonate is hypothesized to have degraded the martian climate to its present state of a generally subfreezing, desiccated desert. The rate for such a conversion under martian conditions is poorly known, so the time scale of climate degradation by this process cannot be easily evaluated. If some models are correct, carbonate formation may have been fast at geological time scales. The experiments of Booth and Kieffer also imply fast (10(exp 6) - 10(exp 7) yr) removal of the missing CO2 inventory, estimated to be 1 - 5 bar, by means of carbonate formation. The timing of formation of many of the fluvial features observed on Mars is, in large part, dependent on when and how fast the atmosphere changed. A knowledge of the rate at which carbonates and nitrates formed is also essential for assessing the probability that life, or its chemical precursors, could have developed on Mars. No previous experiments have quantitatively evaluated the rate of solution for a suite of mobile anions and cations from unaltered minerals and atmospheric gases into liquid water under Mars-like conditions. Such experiments are the focus of this task.

  13. Synchrotron radiation focusing by a Bragg--Fresnel lens

    Since the discovery of x rays and until the present time the possibilities of their controlling and focusing have been widely discussed. In the hard spectrum region (λ∼1 A) the main focusing schemes are the following: geometrical focusing based on incoherent interaction of wave packets reflected by different regions of bending crystals and coherent (dynamic) focusing performed at the cost of the effect of refraction index angular dispersion near the exact Bragg angle value -θB. A main disadvantage of geometrical focusing is low spatial resolution (∼0.1 mm) and temperature stability. In the case of coherent focusing a main disadvantage is a narrow angular aperture (∼10 sec. of arc) at spatial resolution (∼1--10 μm). Recently, advances in the development of diffraction physics and microstructuring technology open up possibilities for fabricating effective focusing x-ray optical elements---Bragg--Fresnel lenses (BFL)---with high spatial resolution (∼0.1 μm) at a wide angular aperture and high temperature stability. The present paper describes the main principles of Bragg--Fresnel optics (BFO). It presents the results on the synchrotron experiment and on observation of focusing. In this work the peculiarities of BFL diffraction contrast formation are investigated and image transmission using a BFL is performed. Possibilities of developing x-ray optical schemes of ultrahigh resolution on the basis of BFL elements are also discussed

  14. On the interplay between star formation and feedback in galaxy formation simulations

    Agertz, Oscar; Kravtsov, Andrey V.

    2014-01-01

    We investigate the star formation-feedback cycle in cosmological galaxy formation simulations, focusing on progenitors of Milky Way (MW)-sized galaxies. We find that in order to reproduce key properties of the MW progenitors, such as semi-empirically derived star formation histories and the shape of rotation curves, our implementation of star formation and stellar feedback requires 1) a combination of local early momentum feedback via radiation pressure and stellar winds and subsequent effici...

  15. MDF: Magnetic Particle Imaging Data Format

    Knopp, Tobias; Bringout, Gael; Ahlborg, Mandy; Rahmer, Jürgen; Hofmann, Martin

    2016-01-01

    Magnetic particle imaging (MPI) is a tomographic method to determine the spatial distribution of magnetic nanoparticles. In this document a file format for the standardized storage of MPI data is introduced. The aim of the Magnetic Particle Imaging Data Format (MDF) is to provide a coherent way of exchanging MPI data acquired with different MPI scanners worldwide. The focus of the file format is on sequence parameters, raw measurement data, calibration data, and reconstruction data. The format is based on the hierarchical document format (HDF) in version 5 (HDF5).

  16. On-chip pumping for pressure mobilization of the focused zones following microchip isoelectric focusing.

    Guillo, Christelle; Karlinsey, James M; Landers, James P

    2007-01-01

    Isoelectric focusing (IEF), traditionally accomplished in slab or tube gels, has also been performed extensively in capillary and, more recently, in microchip formats. IEF separations performed in microchips typically use electroosmotic flow (EOF) or chemical treatment to mobilize the focused zones past the detection point. This report describes the development and optimization of a microchip IEF method in a hybrid PDMS-glass device capable of controlling the mobilization of the focused zones past the detector using on-chip diaphragm pumping. The microchip design consisted of a glass fluid layer (separation channels), a PDMS layer and a glass valve layer (pressure connections and valve seats). Pressure mobilization was achieved on-chip using a diaphragm pump consisting of a series of reversible elastomeric valves, where a central diaphragm valve determined the volume of solution displaced while the gate valves on either side imparted directionality. The pumping rate could be adjusted to control the mobilization flow rate by varying the actuation times and pressure applied to the PDMS to actuate the valves. In order to compare the separation obtained using the chip with that obtained in a capillary, a serpentine channel design was used to match the separation length of the capillary, thereby evaluating the effect of diaphragm pumping itself on the overall separation quality. The optimized mIEF method was applied to the separation of labeled amino acids. PMID:17180213

  17. GSM microwaves and 50 Hz electromagnetic field induce stress response but not apoptosis in human lymphocytes from hypersensitive and healthy persons

    We used specific conditions of exposure to microwaves from a GSM (global system for mobile communication) mobile phone (915 MHz, SAR=0.4 mW/g) and 50 Hz electromagnetic field (EMF, 15 μT amplitude) to investigate the response of lymphocytes from healthy subjects and from persons reporting hypersensitivity to EMF. The groups of hypersensitive and healthy donors were matched by gender and age and the data were analyzed in blind. The changes in chromatin conformation were measured with the method of anomalous viscosity time dependencies (AVTD). 53BP1 protein, which has been shown to co-localize in foci with DNA double strand breaks (DSB), was analyzed by immunostaining in situ. Exposure either to GSM microwaves or EMF/50 Hz resulted in significant condensation of chromatin, which was similar to the effect of heat shock at 41deg C. These effects varied between donors with a trend for prolonged condensation of chromatin in the cells from hypersensitive subjects. Cells from subjects, which were classified as pronounced hypersensitivity, responded to GSM /ELF stronger than cells from matched control subjects, but these differences in responses need to be confirmed in a larger study group. Neither GSM nor ELF exposure induced formation of 53BP1 foci. In contrary, distinct decrease in background level of 53BP1 signaling was observed upon these exposures as well as after heat shock treatments. This decrease correlated with the AVTD data and may indicate decrease in accessibility of 53BP1 to antibodies because of stress-induced chromatin condensation. No apoptosis was induced by exposure to ELF/50 Hz and GSM microwaves. In conclusion, ELF magnetic fields and GSM microwaves under specified conditions of exposure induced stress response in lymphocytes from healthy and hypersensitive donors

  18. Ultrasound focusing images in superlattices

    Narita, Michiko; Tanaka, Yukihiro; Tamura, Shin-ichiro

    2002-03-01

    We study theoretically ultrasound focusing in periodic multilayered structures, or superlattices, by solving the wave equation with the Green function method and calculating the transmitted ultrasound amplitude images of both the longitudinal and transverse modes. The constituent layers assumed are elastically isotropic but the periodically stacked structure is anisotropic. Thus anisotropy of ultrasound propagation is predicted even at low frequencies and it is enhanced significantly at higher frequencies due to the zone-folding effect of acoustic dispersion relations. An additional effect studied is the interference of ultrasound (known as the internal diffraction), which can be recognized when the propagation distance is comparable to the ultrasound wavelength. Numerical examples are developed for millimetre-scale Al/polymer multilayers used recently for imaging experiment with surface acoustic waves.

  19. Tank Focus Area pretreatment activities

    Plans call for the high-level wastes to be retrieved from the tanks and immobilized in a stable waste form suitable for long-term isolation. Chemistry and chemical engineering operations are required to retrieve the wastes, to condition the wastes for subsequent steps, and to reduce the costs of the waste management enterprise. Pretreatment includes those processes between retrieval and immobilization, and includes preparation of suitable feed material for immobilization and separations to partition the waste into streams that yield lower life-cycle costs. Some of the technologies being developed by the Tank Focus Area (TFA) to process these wastes are described. These technologies fall roughly into three areas: (1) solid/liquid separation (SLS), (2) sludge pretreatment, and (3) supernate pretreatment

  20. Focusing telescopes in nuclear astrophysics

    Von Ballmoos, P.; Knodlseder, R.; Sazonov, S.; Griffiths, R.; Bastie, P.; Halloin, H.; Pareschi, G.; Ramsey, B.; Jensen, C.; Buis, E.J.; Ulmer, M.; Giommi, P.; Colafrancesco, S.; Comastri, A.; Barret, D.; Leising, M.; Hernanz, M.; Smith, D.; Abrosimov, N.; Smither, B.; Ubertini, P.; Olive, J.F.; Lund, N.; Pisa, A.; Courtois, P.; Roa, D.; Harrison, F.; Pareschi, G.; Frontera, F.; Von Ballmoos, P.; Barriere, N.; Rando, N.; Borde, J.; Hinglais, E.; Cledassou, R.; Duchon, P.; Sghedoni, M.; Huet, B.; Takahashi, T.; Caroli, E.; Quadrinin, L.; Buis, E.J.; Skinner, G.; Krizmanic, J.; Pareschi, G.; Loffredo, G.; Wunderer, C.; Weidenspointner, G.; Wunderer, C.; Koechlin, L.; Bignami, G.; Von Ballmoos, P.; Tueller, J.; Andritschke, T.; Laurens, A.; Evrard, J

    2005-07-01

    The objective of this workshop is to consider the next generation of instrumentation to be required within the domain of nuclear astrophysics. A small, but growing community has been pursuing various techniques for the focusing of hard X-rays and gamma-rays with the aim of achieving a factor of up to 100 improvement in sensitivity over present technologies. Balloon flight tests of both multilayer mirrors and a Laue lens have been performed and ideas abound. At present, implementation scenarios for space missions are being studied at Esa, CNES, and elsewhere. The workshop will provide a first opportunity for this new community to meet, exchange technological know-how, discuss scientific objectives and synergies, and consolidate implementation approaches within National and European Space Science programs. This document gathers the slides of all the presentations.

  1. Focusing telescopes in nuclear astrophysics

    The objective of this workshop is to consider the next generation of instrumentation to be required within the domain of nuclear astrophysics. A small, but growing community has been pursuing various techniques for the focusing of hard X-rays and gamma-rays with the aim of achieving a factor of up to 100 improvement in sensitivity over present technologies. Balloon flight tests of both multilayer mirrors and a Laue lens have been performed and ideas abound. At present, implementation scenarios for space missions are being studied at Esa, CNES, and elsewhere. The workshop will provide a first opportunity for this new community to meet, exchange technological know-how, discuss scientific objectives and synergies, and consolidate implementation approaches within National and European Space Science programs. This document gathers the slides of all the presentations

  2. Focus: Simon Steen-Andersen

    Simon Steen-Andersen is one of the most performed Danish composers of his generation, not only in Denmark but also internationally. His proliferating performance success has been followed by several honours, e.g. The Carl Nielsen Prize and Kunstpreis Musik from Akademie der Künste in Berlin (both...... 2013), the prize for the best orchestral work at the recently held Doneueschinger Musiktage and The Nordic Council Music Prize in 2014. Seismograf/DMT wishes to celebrate the composer Simon Steen-Andersen. We present and reflect on parts of his comprehensive career, in a Danish and an international...... translation forthcoming) and finally, Rasmus Holmboe reflects on the visual in Simon Steen-Andersen’s music. The images for this Focus have kindly been provided by Ida Bach Jensen. They originate from the documentary Komponist, about the composers Simon Steen-Andersen, Henriette Groth and Eva Noer Kondrup...

  3. Hospitals focus on physician relations.

    Rubright, R

    1987-09-01

    Many hospital administrators are shifting their marketing focus from consumers and referral agents to the hospital's attending physicians. These new comprehensive physician relations or retention programs are much broader than those implemented in the past and are used to build mutual exchanges between hospitals and physicians, sharpen the physicians' awareness of the hospital's most appealing attributes, compete with nearby hospitals that develop their own aggressive physician relations programs, and ensure a more promising financial picture for both parties. "Cutting-edge" physician relations plans in Catholic hospitals include the following: Marketing plans for the medical staff alone or with key medical staff sections; A strong physician data base; A physician referral system; A director of medical affairs; Practice enhancement and business assistance services; A young physicians section; Continuing marketing auditing and research into physicians' opinions, attitudes, and behavior patterns; Physician inclusion in all major programs, services, policies, and events; Programs for physician office staff; Marketing committees consisting of physicians. PMID:10283486

  4. Focusing the partly polarized light

    Borovytsky, Volodymyr

    2015-11-01

    The paper presents the mathematical technique for calculation of three dimensional intensity distribution near a focal point of an optical system in case of partly polarized light. The proposed technique considers a high aperture optical system that focuses a partly polarized parallel beam. The principal idea is based on Huygens-Fresnel principle: a spherical wave at an exit pupil of an optical system is considered as a numerous set of secondary light point sources. Each source emits a partly polarized spherical wave. The polarization orientation of each wave can be calculated using angular pupil coordinates. Modulation of amplitude, phase or polarization can be introduced depending on these pupil coordinates. The total intensity is defined as superposition of complex wave amplitudes taking into account polarization orientation, degree of polarization and orientation of detector aperture. The paper presents the intensity distributions calculated for beams with various types and degrees of polarization.

  5. Centripetal focusing of gyrotactic phytoplankton.

    Cencini, M; Franchino, M; Santamaria, F; Boffetta, G

    2016-06-21

    A suspension of gyrotactic microalgae Chlamydomonas augustae swimming in a cylindrical water vessel in solid-body rotation is studied. Our experiments show that swimming algae form an aggregate around the axis of rotation, whose intensity increases with the rotation speed. We explain this phenomenon by the centripetal orientation of the swimming direction towards the axis of rotation. This centripetal focusing is contrasted by diffusive fluxes due to stochastic reorientation of the cells. The competition of the two effects lead to a stationary distribution, which we analytically derive from a refined mathematical model of gyrotactic swimmers. The temporal evolution of the cell distribution, obtained via numerical simulations of the stochastic model, is in quantitative agreement with the experimental measurements in the range of parameters explored. PMID:27060672

  6. Understanding Galaxy Formation and Evolution

    Avila-Reese, V

    2006-01-01

    The old dream of integrating into one the study of micro and macrocosmos is now a reality. Cosmology, astrophysics, and particle physics intersect in a scenario (but still not a theory) of cosmic structure formation and evolution called Lambda Cold Dark Matter (LCDM) model. This scenario emerged mainly to explain the origin of galaxies. In these lecture notes, I first present a review of the main galaxy properties, highlighting the questions that any theory of galaxy formation should explain. Then, the cosmological framework and the main aspects of primordial perturbation generation and evolution are pedagogically detached. Next, I focus on the ``dark side'' of galaxy formation, presenting a review on LCDM halo assembling and properties, and on the main candidates for non-baryonic dark matter. It is shown how the nature of elemental particles can influence on the features of galaxies and their systems. Finally, the complex processes of baryon dissipation inside the non-linearly evolving CDM halos, formation o...

  7. Focusing of baroclinic tidal energy in a canyon

    Vlasenko, Vasiliy; Stashchuk, Nataliya; Inall, Mark E.; Porter, Marie; Aleynik, Dmitry

    2016-04-01

    Strong three-dimensional focusing of internal tidal energy in the Petite Sole Canyon in the Celtic Sea is analyzed using observational data and numerical modeling. In a deep layer (500-800 m) in the center of the canyon, shear variance was elevated by an order of magnitude. Corresponding large vertical oscillations of deep isotherms and a local maximum of horizontal velocity were replicated numerically using the MITgcm. The elevated internal tidal activity in the deep part of the canyon is explained in terms of the downward propagation and focusing of multiple internal tidal beams generated at the shelf break. The near-circular shape of the canyon head and steep bottom topography throughout the canyon (steeper than the tidal beam) create favorable conditions for the lens-like focusing of tidal energy in the canyon's center. Observations and modeling show that the energy focusing greatly intensifies local diapycnal mixing that leads to local formation of a baroclinic eddy.

  8. STRATEGIC ALLIANCES – THEIR DEFINITION AND FORMATION

    Kinderis, Remigijus; Jucevičius, Giedrius

    2013-01-01

    The article presents analysis of the definition of strategic alliances, the analysis of alliance and the research of a strategic alliance concept; furthermore, it focuses on the contingent hierarchy of alliances. The motives of strategic alliances formation, their categories, groups and benefit for business have been revealed in this article. Special attention is paid to the process of strategic alliance formation and the analysis of factors that influence the formation of strategic alliances...

  9. EDITORIAL: Focus on Attosecond Physics

    Bandrauk, André D.; Krausz, Ferenc; Starace, Anthony F.

    2008-02-01

    future involve using overdense plasmas. Electronic processes on sub-atomic spatio-temporal scales are the basis of chemical physics, atomic, molecular, and optical physics, materials science, and even some life science processes. Research in these areas using the new attosecond tools will advance together with the ability to control electrons themselves. Indeed, we expect that developments will advance in a way that is similar to advances that have occurred on the femtosecond time scale, in which much previous experimental and theoretical work on the interaction of coherent light sources has led to the development of means for 'coherent control' of nuclear motion in molecules. This focus issue of New Journal of Physics is centered on experimental and theoretical advances in the development of new methodologies and tools for electron control on the attosecond time scale. Topics such as the efficient generation of harmonics; the generation of attosecond pulses, including those having only a few cycles and those produced from overdense plasmas; the description of various nonlinear, nonperturbative laser-matter interactions, including many-electron effects and few-cycle pulse effects; the analysis of ultrashort propagation effects in atomic and molecular media; and the development of inversion methods for electron tomography, as well as many other topics, are addressed in the current focus issue dedicated to the new field of 'Attosecond Physics'. Focus on Attosecond Physics Contents Observing the attosecond dynamics of nuclear wavepackets in molecules by using high harmonic generation in mixed gases Tsuneto Kanai, Eiji J Takahashi, Yasuo Nabekawa and Katsumi Midorikawa Core-polarization effects in molecular high harmonic generation G Jordan and A Scrinzi Interferometric autocorrelation of an attosecond pulse train calculated using feasible formulae Y Nabekawa and K Midorikawa Attosecond pulse generation from aligned molecules—dynamics and propagation in H2+ E Lorin, S

  10. SIAM Workshop: Focus on Diversity

    None

    2000-07-12

    The Fourth SlAM Graduate Student Focus on Diversity workshop was held on July 12, 2000 at the Westin Rio Mar Hotel in Rio Grande, Puerto Rico. The Department of Energy provided partial support for this event. The day-long workshop consisted of several different activities. The meeting opened with a discussion of some data collected by the American Mathematical Society on Ph.D.'s awarded in the U.S. to citizens and non-citizens, further classified as blacks, latinos, asians and native americans. The activity continued with nine technical talks by underrepresented minority graduate students, informal luncheon and pizza breaks to foster social interaction, and an evening forum chaired by Dr. Richard Tapia (Rice University) in which issues related to the participation of minorities in national meetings and proposal writing where discussed. These sessions were open to the entire SIAM community and served to highlight the progress, achievements, and aspirations of the workshop participants. The students attended as well the three SlAM plenary talks during the day and the community lecture in the evening. The activity had a lively participation of students and representatives from various academic institutions and sponsoring agencies. In particular, we had the participation of 24 undergraduate students from the Mathematics REU program of the University of Puerto Rico at Humacao.