3,590 research outputs found

    Routing with locality in partitioned-bus meshes

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    We show that adding partitioned-buses (as opposed to long buses that span an entire row or column) to ordinary meshes can reduce the routing time by approximately one-third for permutation routing with locality. A matching time lower bound is also proved. The result can be generalized to multi-packet routing.published_or_final_versio

    Hyperglycemia Has a Greater Impact on Left Ventricle Function in South Asians Than in Europeans

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    OBJECTIVE Diabetes is associated with left ventricular (LV) diastolic and systolic dysfunction. South Asians may be at particular risk of developing LV dysfunction owing to a high prevalence of diabetes. We investigated the role of diabetes and hyperglycemia in LV dysfunction in a community-based cohort of older South Asians and white Europeans. RESEARCH DESIGN AND METHODS Conventional and Doppler echocardiography was performed in 999 participants (542 Europeans and 457 South Asians aged 58–86 years) in a population-based study. Anthropometry, fasting bloods, coronary artery calcification scoring, blood pressure, and renal function were measured. RESULTS Diabetes and hyperglycemia across the spectrum of HbA1c had a greater adverse effect on LV function in South Asians than Europeans (N-terminal-probrain natriuretic peptide Ξ² Β± SE 0.09 Β± 0.04, P = 0.01, vs. βˆ’0.04 Β± 0.05, P = 0.4, P for HbA1c/ethnicity interaction 0.02), diastolic function (E/eβ€² 0.69 Β± 0.12, P < 0.0001, vs. 0.09 Β± 0.2, P = 0.6, P for interaction 0.005), and systolic function (sβ€² βˆ’0.11 Β± 0.06, P = 0.04, vs. 0.14 Β± 0.09, P = 0.1, P for interaction 0.2). Multivariable adjustment for hypertension, microvascular disease, LV mass, coronary disease, and dyslipidemia only partially accounted for the ethnic differences. Adverse LV function in diabetic South Asians could not be accounted for by poorer glycemic control or longer diabetes duration. CONCLUSIONS Diabetes and hyperglycemia have a greater adverse effect on LV function in South Asians than Europeans, incompletely explained by adverse risk factors. South Asians may require earlier and more aggressive treatment of their cardiometabolic risk factors to reduce risks of LV dysfunction

    Finding optimal threshold for correction error reads in DNA assembling

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    Background: DNA assembling is the problem of determining the nucleotide sequence of a genome from its substrings, called reads. In the experiments, there may be some errors on the reads which affect the performance of the DNA assembly algorithms. Existing algorithms, e.g. ECINDEL and SRCorr, correct the error reads by considering the number of times each length-k substring of the reads appear in the input. They treat those length-k substrings appear at least M times as correct substring and correct the error reads based on these substrings. However, since the threshold M is chosen without any solid theoretical analysis, these algorithms cannot guarantee their performances on error correction. Results: In this paper, we propose a method to calculate the probabilities of false positive and false negative when determining whether a length-k substring is correct using threshold M. Based on this optimal threshold M that minimizes the total errors (false positives and false negatives). Experimental results on both real data and simulated data showed that our calculation is correct and we can reduce the total error substrings by 77.6% and 65.1% when compared to ECINDEL and SRCorr respectively. Conclusion: We introduced a method to calculate the probability of false positives and false negatives of the length-k substring using different thresholds. Based on this calculation, we found the optimal threshold to minimize the total error of false positive plus false negative. Β© 2009 Chin et al; licensee BioMed Central Ltd.published_or_final_versio

    Requirement of JNK1 for endothelial cell injury in atherogenesis

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    AbstractObjectiveThe c-Jun N-terminal kinase (JNK) family regulates fundamental physiological processes including apoptosis and metabolism. Although JNK2 is known to promote foam cell formation during atherosclerosis, the potential role of JNK1 is uncertain. We examined the potential influence of JNK1 and its negative regulator, MAP kinase phosphatase-1 (MKP-1), on endothelial cell (EC) injury and early lesion formation using hypercholesterolemic LDLRβˆ’/βˆ’ mice.Methods and resultsTo assess the function of JNK1 in early atherogenesis, we measured EC apoptosis and lesion formation in LDLRβˆ’/βˆ’ or LDLRβˆ’/βˆ’/JNK1βˆ’/βˆ’ mice exposed to a high fat diet for 6 weeks. En face staining using antibodies that recognise active, cleaved caspase-3 (apoptosis) or using Sudan IV (lipid deposition) revealed that genetic deletion of JNK1 reduced EC apoptosis and lesion formation in hypercholesterolemic mice. By contrast, although EC apoptosis was enhanced in LDLRβˆ’/βˆ’/MKP-1βˆ’/βˆ’ mice compared to LDLRβˆ’/βˆ’ mice, lesion formation was unaltered.ConclusionWe conclude that JNK1 is required for EC apoptosis and lipid deposition during early atherogenesis. Thus pharmacological inhibitors of JNK may reduce atherosclerosis by preventing EC injury as well as by influencing foam cell formation

    New first trimester crown-rump length's equations optimized by structured data collection from a French general population

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    --- Objectives --- Prior to foetal karyotyping, the likelihood of Down's syndrome is often determined combining maternal age, serum free beta-HCG, PAPP-A levels and embryonic measurements of crown-rump length and nuchal translucency for gestational ages between 11 and 13 weeks. It appeared important to get a precise knowledge of these scan parameters' normal values during the first trimester. This paper focused on crown-rump length. --- METHODS --- 402 pregnancies from in-vitro fertilization allowing a precise estimation of foetal ages (FA) were used to determine the best model that describes crown-rump length (CRL) as a function of FA. Scan measures by a single operator from 3846 spontaneous pregnancies representative of the general population from Northern France were used to build a mathematical model linking FA and CRL in a context as close as possible to normal scan screening used in Down's syndrome likelihood determination. We modeled both CRL as a function of FA and FA as a function of CRL. For this, we used a clear methodology and performed regressions with heteroskedastic corrections and robust regressions. The results were compared by cross-validation to retain the equations with the best predictive power. We also studied the errors between observed and predicted values. --- Results --- Data from 513 spontaneous pregnancies allowed to model CRL as a function of age of foetal age. The best model was a polynomial of degree 2. Datation with our equation that models spontaneous pregnancies from a general population was in quite agreement with objective datations obtained from 402 IVF pregnancies and thus support the validity of our model. The most precise measure of CRL was when the SD was minimal (1.83mm), for a CRL of 23.6 mm where our model predicted a 49.4 days of foetal age. Our study allowed to model the SD from 30 to 90 days of foetal age and offers the opportunity of using Zscores in the future to detect growth abnormalities. --- Conclusion --- With powerful statistical tools we report a good modeling of the first trimester embryonic growth in the general population allowing a better knowledge of the date of fertilization useful in the ultrasound screening of Down's syndrome. The optimal period to measure CRL and predict foetal age was 49.4 days (9 weeks of gestational age). Our results open the way to the detection of foetal growth abnormalities using CRL Zscores throughout the first trimester

    Standardising terminology and notation for the analysis of demographic processes in marked populations

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    The development of statistical methods for the analysis of demographic processes in marked animal populations has brought with it the challenges of communication between the disciplines of statistics, ecology, evolutionary biology and computer science. In order to aid communication and comprehension, we sought to root out a number of cases of ambiguity, redundancy and inaccuracy in notation and terminology that have developed in the literature. We invited all working in this field to submit topics for resolution and to express their own views. In the ensuing discussion forum it was then possible to establish a series of general principles which were, almost without exception, unanimously accepted. Here we set out the background to the areas of confusion, how these were debated and the conclusions which were reached in each case. We hope that the resulting guidelines will be widely adopted as standard terminology in publications and in software for the analysis of demographic processes in marked animal populationspostprin

    Developing the content of two behavioural interventions : using theory-based interventions to promote GP management of upper respiratory tract infection without prescribing antibiotics #1

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    Background: Evidence shows that antibiotics have limited effectiveness in the management of upper respiratory tract infection (URTI) yet GPs continue to prescribe antibiotics. Implementation research does not currently provide a strong evidence base to guide the choice of interventions to promote the uptake of such evidence-based practice by health professionals. While systematic reviews demonstrate that interventions to change clinical practice can be effective, heterogeneity between studies hinders generalisation to routine practice. Psychological models of behaviour change that have been used successfully to predict variation in behaviour in the general population can also predict the clinical behaviour of healthcare professionals. The purpose of this study was to design two theoretically-based interventions to promote the management of upper respiratory tract infection (URTI) without prescribing antibiotics. Method: Interventions were developed using a systematic, empirically informed approach in which we: selected theoretical frameworks; identified modifiable behavioural antecedents that predicted GPs intended and actual management of URTI; mapped these target antecedents on to evidence-based behaviour change techniques; and operationalised intervention components in a format suitable for delivery by postal questionnaire. Results: We identified two psychological constructs that predicted GP management of URTI: "Self-efficacy," representing belief in one's capabilities, and "Anticipated consequences," representing beliefs about the consequences of one's actions. Behavioural techniques known to be effective in changing these beliefs were used in the design of two paper-based, interactive interventions. Intervention 1 targeted self-efficacy and required GPs to consider progressively more difficult situations in a "graded task" and to develop an "action plan" of what to do when next presented with one of these situations. Intervention 2 targeted anticipated consequences and required GPs to respond to a "persuasive communication" containing a series of pictures representing the consequences of managing URTI with and without antibiotics. Conclusion: It is feasible to systematically develop theoretically-based interventions to change professional practice. Two interventions were designed that differentially target generalisable constructs predictive of GP management of URTI. Our detailed and scientific rationale for the choice and design of our interventions will provide a basis for understanding any effects identified in their evaluation. Trial registration: Clinicaltrials.gov NCT00376142This study is funded by the European Commission Research Directorate as part of a multi-partner program: Research Based Education and Quality Improvement (ReBEQI): A Framework and tools to develop effective quality improvement programs in European healthcare. (Proposal No: QLRT-2001-00657)

    Interleukin-1 regulates multiple atherogenic mechanisms in response to fat feeding

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    Background: Atherosclerosis is an inflammatory process that develops in individuals with known risk factors that include hypertension and hyperlipidaemia, influenced by diet. However, the interplay between diet, inflammatory mechanisms and vascular risk factors requires further research. We hypothesised that interleukin-1 (IL-1) signaling in the vessel wall would raise arterial blood pressure and promote atheroma. Methodology/Principal Findings: Apoe(-/-) and Apoe(-/-)/IL-1R1(-/-) mice were fed high fat diets for 8 weeks, and their blood pressure and atherosclerosis development measured. Apoe(-/-)/IL-R1(-/-) mice had a reduced blood pressure and significantly less atheroma than Apoe(-/-) mice. Selective loss of IL-1 signaling in the vessel wall by bone marrow transplantation also reduced plaque burden (p<0.05). This was associated with an IL-1 mediated loss of endothelium-dependent relaxation and an increase in vessel wall Nox 4. Inhibition of IL-1 restored endothelium-dependent vasodilatation and reduced levels of arterial oxidative stress. Conclusions/Significance: The IL-1 cytokine system links atherogenic environmental stimuli with arterial inflammation, oxidative stress, increased blood pressure and atherosclerosis. This is the first demonstration that inhibition of a single cytokine can block the rise in blood pressure in response to an environmental stimulus. IL-1 inhibition may have profound beneficial effects on atherogenesis in man
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