73 research outputs found
Concurrent stochastic methods for global optimization
The global optimization problem, finding the lowest minimizer of a nonlinear function of several variables that has multiple local minimizers, appears well suited to concurrent computation. This paper presents a new parallel algorithm for the global optimization problem. The algorithm is a stochastic method related to the multi-level single-linkage methods of Rinnooy Kan and Timmer for sequential computers. Concurrency is achieved by partitioning the work of each of the three main parts of the algorithm, sampling, local minimization start point selection, and multiple local minimizations, among the processors. This parallelism is of a coarse grain type and is especially well suited to a local memory multiprocessing environment. The paper presents test results of a distributed implementation of this algorithm on a local area network of computer workstations. It also summarizes the theoretical properties of the algorithm
Mediterranean diet and atrial fibrillation: lessons learned from the AFHRI case-control study
A relationship between lifestyle, diet, and atrial fibrillation (AF) remains unclear. Except for alcohol consumption, AF guidelines do not differentiate specific advice for this rhythm disorder. The aim of this study was to investigate the association between adherence to healthy dietary patterns and the presence of AF, among 104 low risk participants from the 1:1 matched case-control AFHRI (Atrial Fibrillation in High-Risk Individuals) study. Dietary data were obtained using a three-day food record. Adapted German versions of the validated 14-item Mediterranean Diet Adherence Screener (MEDAS) and the validated eight-item Healthy Eating Index (HEI) from the Epic Study served as the basis for data derivation. The median age of the study participants was 63.0 years, 73.1% were men. In multivariable adjusted binary logistic regression analyses, we found inverse associations between both dietary indices (MEDAS: Median = 3, HEI: Median = 54.9) and the presence of AF (odds ratio for MEDAS: 0.65, 95% confidence interval (CI): 0.47-0.91, odds ratio for HEI: 0.60, 95% CI 0.39-0.95). Further clinical studies are needed to confirm the extent to which high quality dietary patterns such as a Mediterranean diet influence the onset and natural history of AF, in order to provide dietary counselling
Troponin I and cardiovascular risk prediction in the general population: the BiomarCaRE consortium
Our aims were to evaluate the distribution of troponin I concentrations in population cohorts across Europe, to characterize the association with cardiovascular outcomes, to determine the predictive value beyond the variables used in the ESC SCORE, to test a potentially clinically relevant cut-off value, and to evaluate the improved eligibility for statin therapy based on elevated troponin I concentrations retrospectively
Genetics and beyond - the transcriptome of human monocytes and disease susceptibility
BACKGROUND: Variability of gene expression in human may link gene sequence variability and phenotypes; however, non-genetic variations, alone or in combination with genetics, may also influence expression traits and have a critical role in physiological and disease processes. METHODOLOGY/PRINCIPAL FINDINGS: To get better insight into the overall variability of gene expression, we assessed the transcriptome of circulating monocytes, a key cell involved in immunity-related diseases and atherosclerosis, in 1,490 unrelated individuals and investigated its association with >675,000 SNPs and 10 common cardiovascular risk factors. Out of 12,808 expressed genes, 2,745 expression quantitative trait loci were detected (P<5.78x10(-12)), most of them (90%) being cis-modulated. Extensive analyses showed that associations identified by genome-wide association studies of lipids, body mass index or blood pressure were rarely compatible with a mediation by monocyte expression level at the locus. At a study-wide level (P<3.9x10(-7)), 1,662 expression traits (13.0%) were significantly associated with at least one risk factor. Genome-wide interaction analyses suggested that genetic variability and risk factors mostly acted additively on gene expression. Because of the structure of correlation among expression traits, the variability of risk factors could be characterized by a limited set of independent gene expressions which may have biological and clinical relevance. For example expression traits associated with cigarette smoking were more strongly associated with carotid atherosclerosis than smoking itself. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that the monocyte transcriptome is a potent integrator of genetic and non-genetic influences of relevance for disease pathophysiology and risk assessment
Flux Phase as a Dynamic Jahn-Teller Phase: Berryonic Matter in the Cuprates?
There is considerable evidence for some form of charge ordering on the
hole-doped stripes in the cuprates, mainly associated with the low-temperature
tetragonal phase, but with some evidence for either charge density waves or a
flux phase, which is a form of dynamic charge-density wave. These three states
form a pseudospin triplet, demonstrating a close connection with the E X e
dynamic Jahn-Teller effect, suggesting that the cuprates constitute a form of
Berryonic matter. This in turn suggests a new model for the dynamic Jahn-Teller
effect as a form of flux phase. A simple model of the Cu-O bond stretching
phonons allows an estimate of electron-phonon coupling for these modes,
explaining why the half breathing mode softens so much more than the full
oxygen breathing mode. The anomalous properties of provide a coupling
(correlated hopping) which acts to stabilize density wave phases.Comment: Major Revisions: includes comparisons with specific cuprate phonon
modes, 16 eps figures, revte
Sex-Specific Epidemiology of Heart Failure Risk and Mortality in Europe Results From the BiomarCaRE Consortium
OBJECTIVES: This study investigates differences between women and men in heart failure (HF) risk and mortality.BACKGROUND: Sex differences in HF epidemiology are insufficiently understood.METHODS: In 78,657 individuals (median 49.5 years of age; age range 24.1 to 98.7 years; 51.7% women) from community-based European studies (FINRISK, DanMONICA, Moli-sani, Northern Sweden) of the BiomarCaRE (Biomarker for Cardiovascular Risk Assessment in Europe) consortium, the association between incident HF and mortality, the relationship of cardiovascular risk factors, prevalent cardiovascular diseases, biomarkers (C-reactive protein [CRP]; N-terminal pro-B-type natriuretic peptide [NT-proBNP]) with incident HF, and their attributable risks were tested in women vs. men.RESULTS: Over a median follow-up of 12.7 years, fewer HF cases were observed in women (n = 2,399 [5.9%]) than in men (n = 2,771 [7.3%]). HF incidence increased markedly after 60 years of age, initially with a more rapid increase in men, whereas incidence in women exceeded that of men after 85 years of age. HF onset substantially increased mortality risk in both sexes. Multivariable-adjusted Cox models showed the following sex differences for the association with incident HF: systolic blood pressure hazard ratio (HR) according to SD in women of 1.09 (95% confidence interval [CI]: 1.05 to 1.14) versus HR of 1.19 (95% CI: 1.14 to 1.24) in men; heart rate HR of 0.98 (95% CI: 0.93 to 1.03) in women versus HR of 1.09 (95% CI: 1.04 to 1.13) in men; CRP HR of 1.10 (95% CI: 1.00 to 1.20) in women versus HR of 1.32 (95% CI: 1.24 to 1.41) in men; and NT-proBNP HR of 1.54 (95% CI: 1.37 to 1.74) in women versus HR of 1.89 (95% CI: 1.75 to 2.05) in men. Population-attributable risk of all risk factors combined was 59.0% in women and 62.9% in men.CONCLUSIONS: Women had a lower risk for HF than men. Sex differences were seen for systolic blood pressure, heart rate, CRP, and NT-proBNP, with a lower HF risk in women. (C) 2019 by the American College of Cardiology Foundation.</div
RANTES/CCL5 and risk for coronary events: Results from the MONICA/KORA Augsburg case-cohort, Athero-express and CARDIoGRAM studies
Background: The chemokine RANTES (regulated on activation, normal T-cell expressed and secreted)/CCL5 is involved in the pathogenesis of cardiovascular disease in mice, whereas less is known in humans. We hypothesised that its relevance for atherosclerosis should be reflected by associations between CCL5 gene variants, RANTES serum concentrations and protein levels in atherosclerotic plaques and risk for coronary events. Methods and Findings: We conducted a case-cohort study within the population-based MONICA/KORA Augsburg studies. Baseline RANTES serum levels were measured in 363 individuals with incident coronary events and 1,908 non-cases (mean follow-up: 10.2±
Fifteen Genetic Loci Associated with the Electrocardiographic P Wave
The P wave on an ECG is a measure of atrial electric function, and its characteristics may serve as predictors for atrial arrhythmias. Increased mean P-wave duration and P-wave terminal force traditionally have been used as markers for left atrial enlargement, and both have been associated with increased risk of atrial fibrillation. Here, we explore the genetic basis of P-wave morphology through meta-analysis of genome-wide association study results for P-wave duration and P-wave terminal force from 12 cohort studies. Methods and Results - We included 44 456 individuals, of which 6778 (16%) were of African ancestry. Genotyping, imputation, and genome-wide association study were performed at each study site. Summary-level results were meta-analyzed centrally using inverse-variance weighting. In meta-analyses of P-wave duration, we identified 6 significant (P<5×10-8) novel loci and replicated a prior association with SCN10A. We identified 3 loci at SCN5A, TBX5, and CAV1/CAV2 that were jointly associated with the PR interval, PR segment, and P-wave duration. We identified 6 novel loci in meta-analysis of P-wave terminal force. Four of the identified genetic loci were significantly associated with gene expression in 329 left atrial samples. Finally, we observed that some of the loci associated with the P wave were linked to overall atrial conduction, whereas others identified distinct phases of atrial conduction. Conclusions - We have identified 6 novel genetic loci associated with P-wave duration and 6 novel loci associated with P-wave terminal force. Future studies of these loci may aid in identifying new targets for drugs that may modify atrial conduction or treat atrial arrhythmias
The DZHK research platform: maximisation of scientific value by enabling access to health data and biological samples collected in cardiovascular clinical studies
The German Centre for Cardiovascular Research (DZHK) is one of the German Centres for Health Research and aims to conduct early and guideline-relevant studies to develop new therapies and diagnostics that impact the lives of people with cardiovascular disease. Therefore, DZHK members designed a collaboratively organised and integrated research platform connecting all sites and partners. The overarching objectives of the research platform are the standardisation of prospective data and biological sample collections among all studies and the development of a sustainable centrally standardised storage in compliance with general legal regulations and the FAIR principles. The main elements of the DZHK infrastructure are web-based and central units for data management, LIMS, IDMS, and transfer office, embedded in a framework consisting of the DZHK Use and Access Policy, and the Ethics and Data Protection Concept. This framework is characterised by a modular design allowing a high standardisation across all studies. For studies that require even tighter criteria additional quality levels are defined. In addition, the Public Open Data strategy is an important focus of DZHK. The DZHK operates as one legal entity holding all rights of data and biological sample usage, according to the DZHK Use and Access Policy. All DZHK studies collect a basic set of data and biosamples, accompanied by specific clinical and imaging data and biobanking. The DZHK infrastructure was constructed by scientists with the focus on the needs of scientists conducting clinical studies. Through this, the DZHK enables the interdisciplinary and multiple use of data and biological samples by scientists inside and outside the DZHK. So far, 27 DZHK studies recruited well over 11,200 participants suffering from major cardiovascular disorders such as myocardial infarction or heart failure. Currently, data and samples of five DZHK studies of the DZHK Heart Bank can be applied for
On mutual impact of numerical linear algebra and large-scale optimization with focus on interior point methods
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