590 research outputs found

    Cohomology for infinitesimal unipotent algebraic and quantum groups

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    In this paper we study the structure of cohomology spaces for the Frobenius kernels of unipotent and parabolic algebraic group schemes and of their quantum analogs. Given a simple algebraic group GG, a parabolic subgroup PJP_J, and its unipotent radical UJU_J, we determine the ring structure of the cohomology ring H∙((UJ)1,k)H^\bullet((U_J)_1,k). We also obtain new results on computing H∙((PJ)1,L(λ))H^\bullet((P_J)_1,L(\lambda)) as an LJL_J-module where L(λ)L(\lambda) is a simple GG-module with high weight λ\lambda in the closure of the bottom pp-alcove. Finally, we provide generalizations of all our results to the quantum situation.Comment: 18 pages. Some proofs streamlined over previous version. Additional details added to some proofs in Section

    Sustainable Land Use: Methodology and Application

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    The chapters in this volume are edited versions of papers presented at the NATO Ad- vanced Research Workshop on Environmental Change Adaptation and Security held in Budapest, Hungary, from October 16 - 18, 1997. As is evident in this volume, the papers ranged from descriptions of environmental and health issues in Russia and Eastern Europe to models of sustainable land use. This diversity of perspectives on environ- ment and security is indicative of both the breadth of this new area of research as well as the varied background of the researchers involved. The discussions at the NATO workshop were remarkably animated and exciting, not surprising given the interest in the topic. I think this vitality is reflected in the papers in this volume as well. The main purpose of the NATO ARW is to foster research links among researchers from NATO countries and Central and Eastern European States, Russia, and the Newly Independent States. In editing this volume, a decision was made to keep to the spirit of this purpose and-if at all possible-include all papers prepared for the workshop. This required extensive editing and rewriting of some of the papers (and consequent delays in production). A determination was made early in the process by the workshop steering committee that the value of publishing the entire collection of articles out- weighed the advantages of accepting only a limited number

    Exploring and challenging the network of angiogenesis

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    Angiogenesis is one of the hallmarks of cancer and, as such, one of the alternative general targets for anticancer therapy. Since angiogenesis is a complex process involving a high number of interconnected components, a network approach would be a convenient systemic way to analyse responses to directed drug attacks. Herein we show that, although the angiogenic network is easily broken by short combinations of directed attacks, it still remains essentially functional by keeping the global patterns and local efficiency essentially unaltered after these attacks. This is a clear sign of its high robustness and resilience and stresses the need of directed, combined attacks for an effective blockade of the process. The results of this theoretical study could be relevant for the design of new antiangiogenic therapies and the selection of their targets

    Genetic analysis of the GLUT10 glucose transporter (SLC2A10) polymorphisms in Caucasian American type 2 diabetes

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    BACKGROUND: GLUT10 (gene symbol SLC2A10) is a facilitative glucose transporter within the type 2 diabetes (T2DM)-linked region on chromosome 20q12-13.1. Therefore, we evaluated GLUT10 as a positional candidate gene for T2DM in Caucasian Americans. METHODS: Twenty SNPs including 4 coding, 10 intronic and 6 5' and 3' to the coding sequence were genotyped across a 100 kb region containing the SLC2A10 gene in DNAs from 300 T2DM cases and 310 controls using the Sequenom MassArray Genotyping System. Allelic association was evaluated, and linkage disequilibrium (LD) and haplotype structure of SLC2A10 were also determined to assess whether any specific haplotypes were associated with T2DM. RESULTS: Of these variants, fifteen had heterozygosities greater than 0.80 and were analyzed further for association with T2DM. No evidence of significant association was observed for any variant with T2DM (all P ≥ 0.05), including Ala206Thr (rs2235491) which was previously reported to be associated with fasting insulin. Linkage disequilibrium analysis suggests that the SLC2A10 gene is contained in a single haplotype block of 14 kb. Haplotype association analysis with T2DM did not reveal any significant differences between haplotype frequencies in T2DM cases and controls. CONCLUSION: From our findings, we can conclude that sequence variants in or near GLUT10 are unlikely to contribute significantly to T2DM in Caucasian Americans

    The sex locus is tightly linked to factors conferring sex-specific lethal effects in the mosquito Aedes aegypti

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    In many taxa, sex chromosomes are heteromorphic and largely non-recombining. Evolutionary models predict that spread of recombination suppression on the Y chromosome is fueled by the accumulation of sexually antagonistic alleles in close linkage to the sex determination region. However, empirical evidence for the existence of sexually antagonistic alleles is scarce. In the mosquito Aedes aegypti, the sex-determining chromosomes are homomorphic. The region of suppressed recombination, which surrounds the male-specific sex-determining gene, remains very small, despite ancient origin of the sex chromosomes in the Aedes lineage. We conducted a genetic analysis of the A. aegypti chromosome region tightly linked to the sex locus. We used a strain with an enhanced green fluorescent protein (EGFP)-tagged transgene inserted near the male-determining gene to monitor crossing-over events close to the boundary of the sex-determining region (SDR), and to trace the inheritance pattern of the transgene in relation to sex. In a series of crossing experiments involving individuals with a recombinant sex chromosome we found developmental abnormalities leading to 1:2 sex biases, caused by lethality of half of the male or female progeny. Our results suggest that various factors causing sex-specific lethal effects are clustered within the neighborhood of the SDR, which in the affected sex are likely lost or gained through recombination, leading to death. These may include genes that are recessive lethal, vital for development and/or sexually antagonistic. The sex chromosome fragment in question represents a fascinating test case for the analysis of processes that shape stable boundaries of a non-recombining region

    Changes in heart failure medications in patients hospitalised and discharged

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    BACKGROUND: To date, evidence-based recommendations help doctors to manage patients with heart failure (HF). However, the implementation of these recommendations in primary care is still problematic as beneficial drugs are infrequently prescribed. The aim of the study was to determine whether admission to hospital increases usage of beneficial HF medication and if this usage is maintained directly after discharge. METHODS: The study was conducted from November 2002 until January 2004. In 77 patients hospitalised with heart failure (HF), the medication prescribed by the referring general practitioner (GP) and drug treatment directed by the hospital physicians was documented. Information regarding the post-discharge (14 d) therapy by the GP was evaluated via a telephone interview. Ejection fraction values, comorbidity and specifics regarding diagnostic or therapeutic intervention were collected by chart review. RESULTS: When compared to the referring GPs, hospital physicians prescribed more ACE-inhibitors (58.4% vs. 76.6%; p = 0.001) and beta-blockers of proven efficacy in HF (metoprolol, bisoprolol, carvedilol; 58.4% vs. 81.8%). Aldosterone antagonists were also administered more frequently in the hospital setting compared to general practice (14.3% vs. 37.7%). The New York Heart Association classification for heart failure did not influence whether aldosterone antagonists were administered either in primary or secondary care. Fourteen days after discharge, there was no significant discontinuity in discharge medication. CONCLUSION: Patients suffering from HF were more likely to receive beneficial medication in hospital than prior to admission. The treatment regime then remained stable two weeks after discharge. We suggest that findings on drug continuation in different cardiovascular patients might be considered validated for patients with HF

    Functional Insight into the C-Terminal Extension of Halolysin SptA from Haloarchaeon Natrinema sp. J7

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    Halolysin SptA from haloarchaeon Natrinema sp. J7 consists of a subtilisin-like catalytic domain and a C-terminal extension (CTE) containing two cysteine residues. In this report, we have investigated the function of the CTE using recombinant enzymes expressed in Haloferax volcanii WFD11. Deletion of the CTE greatly reduced but did not abolish protease activity, which suggests that the CTE is not essential for enzyme folding. Mutational analysis suggests that residues Cys303 and Cys338 within the CTE form a disulfide bond that make this domain resistant to autocleavage and proteolysis under hypotonic conditions. Characterization of full-length and CTE-truncation enzymes indicates the CTE not only confers extra stability to the enzyme but also assists enzyme activity on protein substrates by facilitating binding at high salinities. Interestingly, homology modeling of the CTE yields a β-jelly roll-like structure similar to those seen in Claudin-binding domain of Clostridium perfringens enterotoxin (clostridial C-CPE) and collagen binding domain (CBD), and the CTE also possesses collagen-binding activity, making it a potential candidate as an anchoring unit in drug delivery systems

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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