203 research outputs found
Levels of self-consistency in the GW approximation
We perform calculations on atoms and diatomic molecules at different
levels of self-consistency and investigate the effects of self-consistency on
total energies, ionization potentials and on particle number conservation. We
further propose a partially self-consistent scheme in which we keep the
correlation part of the self-energy fixed within the self-consistency cycle.
This approximation is compared to the fully self-consistent results and to
the and the approximations. Total energies, ionization
potentials and two-electron removal energies obtained with our partially
self-consistent approximation are in excellent agreement with fully
self-consistent results while requiring only a fraction of the
computational effort. We also find that self-consistent and partially
self-consistent schemes provide ionization energies of similar quality as the
values but yield better total energies and energy differences.Comment: 11 pages, 3 figures, 3 table
Cluster virial expansion for the equation of state of partially ionized hydrogen plasma
We study the contribution of electron-atom interaction to the equation of
state for partially ionized hydrogen plasma using the cluster-virial expansion.
For the first time, we use the Beth-Uhlenbeck approach to calculate the second
virial coefficient for the electron-atom (bound cluster) pair from the
corresponding scattering phase-shifts and binding energies. Experimental
scattering cross-sections as well as phase-shifts calculated on the basis of
different pseudopotential models are used as an input for the Beth-Uhlenbeck
formula. By including Pauli blocking and screening in the phase-shift
calculation, we generalize the cluster-virial expansion in order to cover also
near solid density plasmas. We present results for the electron-atom
contribution to the virial expansion and the corresponding equation of state,
i.e. pressure, composition, and chemical potential as a function of density and
temperature. These results are compared with semi-empirical approaches to the
thermodynamics of partially ionized plasmas. Avoiding any ill-founded input
quantities, the Beth-Uhlenbeck second virial coefficient for the electron-atom
interaction represents a benchmark for other, semi-empirical approaches.Comment: 16 pages, 10 figures, and 5 tables, resubmitted to PR
Trends in Incidence of Hospitalized Acute Myocardial Infarction in the Cardiovascular Research Network (CVRN)
Monitoring trends in cardiovascular events can provide key insights into the effectiveness of prevention efforts. Leveraging data from electronic health records provides a unique opportunity to examine contemporary, community-based trends in acute myocardial infarction hospitalizations
Associations of fish oil and vitamin B and E supplementation with cardiovascular outcomes and mortality in people receiving haemodialysis: a review
Dynamic metabolomic data analysis: a tutorial review
In metabolomics, time-resolved, dynamic or temporal data is more and more collected. The number of methods to analyze such data, however, is very limited and in most cases the dynamic nature of the data is not even taken into account. This paper reviews current methods in use for analyzing dynamic metabolomic data. Moreover, some methods from other fields of science that may be of use to analyze such dynamic metabolomics data are described in some detail. The methods are put in a general framework after providing a formal definition on what constitutes a ‘dynamic’ method. Some of the methods are illustrated with real-life metabolomics examples
Lack of association between the Trp719Arg polymorphism in kinesin-like protein-6 and coronary artery disease in 19 case-control studies
An international review of tobacco smoking in the medical profession: 1974–2004
Background\ud
Tobacco smoking by physicians represents a contentious issue in public health, and regardless of what country it originates from, the need for accurate, historical data is paramount. As such, this article provides an international comparison of all modern literature describing the tobacco smoking habits of contemporary physicians.\ud
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Methods\ud
A keyword search of appropriate MeSH terms was initially undertaken to identify relevant material, after which the reference lists of manuscripts were also examined to locate further publications.\ud
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Results\ud
A total of 81 English-language studies published in the past 30 years met the inclusion criteria. Two distinct trends were evident. Firstly, most developed countries have shown a steady decline in physicians' smoking rates during recent years. On the other hand, physicians in some developed countries and newly-developing regions still appear to be smoking at high rates. The lowest smoking prevalence rates were consistently documented in the United States, Australia and the United Kingdom. Comparison with other health professionals suggests that fewer physicians smoke when compared to nurses, and sometimes less often than dentists.\ud
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Conclusion\ud
Overall, this review suggests that while physicians' smoking habits appear to vary from region to region, they are not uniformly low when viewed from an international perspective. It is important that smoking in the medical profession declines in future years, so that physicians can remain at the forefront of anti-smoking programs and lead the way as public health exemplars in the 21st century
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Thomson Scattering at FLASH - Status Report
The basic idea is to implement Thomson scattering with free electron laser (FEL) radiation at near-solid density plasmas as a diagnostic method which allows the determination of plasma temperatures and densities in the warm dense matter (WDM) regime (free electron density of n{sub e} = 10{sup 21}-10{sup 26} cm{sup -3} with temperatures of several eV). The WDM regime [1] at near-solid density (n{sub e} = 10{sup 21}-10{sup 22} cm{sup -3}) is of special interest because, it is where the transition from an ideal plasma to a degenerate, strongly coupled plasma occurs. A systematic understanding of this largely unknown WDM domain is crucial for the modeling and understanding of contemporary plasma experiments, like laser shock-wave or Z-pinch experiments as well as for inertial confinement fusion (ICF) experiments as the plasma evolution follows its path through this domain
Homocysteine and Coronary Heart Disease: Meta-analysis of MTHFR Case-Control Studies, Avoiding Publication Bias
Robert Clarke and colleagues conduct a meta-analysis of unpublished datasets to examine the causal relationship between elevation of homocysteine levels in the blood and the risk of coronary heart disease. Their data suggest that an increase in homocysteine levels is not likely to result in an increase in risk of coronary heart disease
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±
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