164 research outputs found
Structurally-driven magnetic state transition of biatomic Fe chains on Ir(001)
Using first-principles calculations, we demonstrate that the magnetic
exchange interaction and the magnetocrystalline anisotropy of biatomic Fe
chains grown in the trenches of the 5x1 reconstructed Ir(001) surface depend
sensitively on the atomic arrangement of the Fe atoms. Two structural
configurations have been considered which are suggested from recent
experiments. They differ by the local symmetry and the spacing between the two
strands of the biatomic Fe chain. Since both configurations are very close in
total energy they may coexist in experiment. We have investigated collinear
ferro- and antiferromagnetic solutions as well as a collinear state with two
moments in one direction and one in the opposite direction (up-down-up-state).
For the structure with a small interchain spacing, there is a strong exchange
interaction between the strands and the ferromagnetic state is energetically
favorable. In the structure with larger spacing, the two strands are
magnetically nearly decoupled and exhibit antiferromagnetic order along the
chain. In both cases, due to hybridization with the Ir substrate the exchange
interaction along the chain axis is relatively small compared to freestanding
biatomic iron chains. The easy magnetization axis of the Fe chains also
switches with the structural configuration and is out-of-plane for the
ferromagnetic chains with small spacing and along the chain axis for the
antiferromagnetic chains with large spacing between the two strands. Calculated
scanning tunneling microscopy images and spectra suggest the possibility to
experimentally distinguish between the two structural and magnetic
configurations.Comment: Accepted for publication in Physical Review
Massively parallel density functional calculations for thousands of atoms: KKRnano
Applications of existing precise electronic-structure methods based on density functional theory are typically limited to the treatment of about 1000 inequivalent atoms, which leaves unresolved many open questions in material science, e. g., on complex defects, interfaces, dislocations, and nanostructures. KKRnano is a new massively parallel linear scaling all-electron density functional algorithm in the framework of the Korringa-Kohn-Rostoker (KKR) Green's-function method. We conceptualized, developed, and optimized KKRnano for large-scale applications of many thousands of atoms without compromising on the precision of a full-potential all-electron method, i.e., it is a method without any shape approximation of the charge density or potential. A key element of the new method is the iterative solution of the sparse linear Dyson equation, which we parallelized atom by atom, across energy points in the complex plane and for each spin degree of freedom using the message passing interface standard, followed by a lower-level OpenMP parallelization. This hybrid four-level parallelization allows for an efficient use of up to 100 000 processors on the latest generation of supercomputers. The iterative solution of the Dyson equation is significantly accelerated, employing preconditioning techniques making use of coarse-graining principles expressed in a block-circulant preconditioner. In this paper, we will describe the important elements of this new algorithm, focusing on the parallelization and preconditioning and showing scaling results for NiPd alloys up to 8192 atoms and 65 536 processors. At the end, we present an order-N algorithm for large-scale simulations of metallic systems, making use of the nearsighted principle of the KKR Green's-function approach by introducing a truncation of the electron scattering to a local cluster of atoms, the size of which is determined by the requested accuracy. By exploiting this algorithm, we show linear scaling calculations of more than 16 000 NiPd atoms
Оценивание финансово-экономической безопасности предприятий молокоперерабатывающей отрасли
The essence of the concept “financial and economic security of the enterprise” is
covered. Methodological approaches to the enterprise financial and economic security evaluation
are considered, enabling the method of index numberrating score of the enterprise financial and
economic security to be found. Dynamics of milk anddairy production in Ukraine has been studied.
Ukrainian regions leading in liquid processed milk production have been identified. Dynamics of
milk and dairy production per man has been analyzed which allowed to find out the annual
increase in demand per man. Integrated index of the dairy enterprise financial and economic
security has been evaluated. As a result, the ways to increase the managerial efficiency of financial
and economic security of the following enterprises:PJSC "Dubnomoloko", PJSC "Kupyans'ki milk
canning plant", PJSC the "Yagotyns'ki creamery", PJSC the "Pervomais'ki milk canning plant" are
offered.У статті розкрито сутність поняття фінансово-економічної безпеки
підприємства. Розглянуто методичні підходи щодо оцінювання фінансово-економічної
безпеки підприємства, що дозволило виявити підхід рейтингової оцінки показника
фінансово-економічної безпеки підприємства. Досліджено динаміку виробництва молока та
молочних продуктів України. Виявити області України, які є лідерами з виробництва молока
рідкого обробленого. Проаналізовано динаміку виробництва молока та молочних продуктів
на одну особу, що дозволило встановити щорічне зростання попиту на одну особу.
Визначено підприємства молокопереробної галузі. Проведено оцінку інтегрального
показника фінансово-економічної безпеки підприємств молокопереробної галузі. За
результатами оцінки запропоновано шляхи підвищення ефективності управління фінансово-економічної безпеки таких підприємств, як: ПАТ «Дубномолоко», ПАТ «Куп’янський
молочноконсервний комбінат», ПАТ «Яготинський маслозавод», ПАТ «Первомайський
молочноконсервний комбінат».В статье раскрыто сущность понятия финансово-экономическая
безопасность предприятия. Рассмотрено методические подходы относительно оценивания
финансово-экономической безопасности предприятия, что позволило выявить поход
рейтинговой оценки показателя финансово-экономической безопасности предприятия.
Исследовано динамику производства молока и молочных продуктов Украины. Выявлены
области Украины, которые являются лидерами по производству молока жидкого
обработанного. Проанализировано динамику производства молока и молочных продуктов на
одного человека, что позволило установить ежегодный рост спроса на одного человека.
Определены предприятия молокоперерабатывающей отрасли. Проведена оценка
интегрального показателя финансово-экономической безопасности предприятий
молокоперерабатывающей отрасли. По результатам оценки предложены пути повышения
эффективности управления финансово-экономической безопасности таких предприятий,
как: ПАО «Дубномолоко», ПАО «Купянский молочноконсервный комбинат», ПАО
«Яготинский маслозавод», ПАО «Первомайский молочноконсервный комбинат»
Application of non-HDL cholesterol for population-based cardiovascular risk stratification: results from the Multinational Cardiovascular Risk Consortium.
BACKGROUND: The relevance of blood lipid concentrations to long-term incidence of cardiovascular disease and the relevance of lipid-lowering therapy for cardiovascular disease outcomes is unclear. We investigated the cardiovascular disease risk associated with the full spectrum of bloodstream non-HDL cholesterol concentrations. We also created an easy-to-use tool to estimate the long-term probabilities for a cardiovascular disease event associated with non-HDL cholesterol and modelled its risk reduction by lipid-lowering treatment. METHODS: In this risk-evaluation and risk-modelling study, we used Multinational Cardiovascular Risk Consortium data from 19 countries across Europe, Australia, and North America. Individuals without prevalent cardiovascular disease at baseline and with robust available data on cardiovascular disease outcomes were included. The primary composite endpoint of atherosclerotic cardiovascular disease was defined as the occurrence of the coronary heart disease event or ischaemic stroke. Sex-specific multivariable analyses were computed using non-HDL cholesterol categories according to the European guideline thresholds, adjusted for age, sex, cohort, and classical modifiable cardiovascular risk factors. In a derivation and validation design, we created a tool to estimate the probabilities of a cardiovascular disease event by the age of 75 years, dependent on age, sex, and risk factors, and the associated modelled risk reduction, assuming a 50% reduction of non-HDL cholesterol. FINDINGS: Of the 524 444 individuals in the 44 cohorts in the Consortium database, we identified 398 846 individuals belonging to 38 cohorts (184 055 [48·7%] women; median age 51·0 years [IQR 40·7-59·7]). 199 415 individuals were included in the derivation cohort (91 786 [48·4%] women) and 199 431 (92 269 [49·1%] women) in the validation cohort. During a maximum follow-up of 43·6 years (median 13·5 years, IQR 7·0-20·1), 54 542 cardiovascular endpoints occurred. Incidence curve analyses showed progressively higher 30-year cardiovascular disease event-rates for increasing non-HDL cholesterol categories (from 7·7% for non-HDL cholesterol <2·6 mmol/L to 33·7% for ≥5·7 mmol/L in women and from 12·8% to 43·6% in men; p<0·0001). Multivariable adjusted Cox models with non-HDL cholesterol lower than 2·6 mmol/L as reference showed an increase in the association between non-HDL cholesterol concentration and cardiovascular disease for both sexes (from hazard ratio 1·1, 95% CI 1·0-1·3 for non-HDL cholesterol 2·6 to <3·7 mmol/L to 1·9, 1·6-2·2 for ≥5·7 mmol/L in women and from 1·1, 1·0-1·3 to 2·3, 2·0-2·5 in men). The derived tool allowed the estimation of cardiovascular disease event probabilities specific for non-HDL cholesterol with high comparability between the derivation and validation cohorts as reflected by smooth calibration curves analyses and a root mean square error lower than 1% for the estimated probabilities of cardiovascular disease. A 50% reduction of non-HDL cholesterol concentrations was associated with reduced risk of a cardiovascular disease event by the age of 75 years, and this risk reduction was greater the earlier cholesterol concentrations were reduced. INTERPRETATION: Non-HDL cholesterol concentrations in blood are strongly associated with long-term risk of atherosclerotic cardiovascular disease. We provide a simple tool for individual long-term risk assessment and the potential benefit of early lipid-lowering intervention. These data could be useful for physician-patient communication about primary prevention strategies. FUNDING: EU Framework Programme, UK Medical Research Council, and German Centre for Cardiovascular Research
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Early Ocean Dispersal Patterns of Columbia River Chinook and Coho Salmon
Several evolutionarily significant units (ESUs) of Columbia River basin Chinook Salmon Oncorhynchus tshawytscha and Coho Salmon O. kisutch are listed as threatened or endangered under the U.S. Endangered Species Act. Yet little is known about the spatial and temporal distributions of these ESUs immediately following ocean entry, when year-class success may be determined. We documented differences in dispersal patterns during the early ocean period among groups defined by ESU, adult run timing, and smolt age. Between 1995 and 2006, 1,896 coded-wire-tagged juvenile fish from the Columbia River basin were recovered during 6,142 research trawl events along the West Coast of North America. Three distinct ocean dispersal patterns were observed: (1) age-1 (yearling) mid and upper Columbia River spring-run and Snake River spring–summer-run Chinook Salmon migrated rapidly northward and by late summer were not found south of Vancouver Island; (2) age-0 (subyearling) lower Columbia River fall, upper Columbia River summer, upper Columbia River fall, and Snake River fall Chinook Salmon dispersed slowly, remaining mainly south of Vancouver Island through autumn; and (3) age-1 lower Columbia River spring, upper Columbia River summer, and upper Willamette River spring Chinook Salmon and Coho Salmon were widespread along the coast from summer through fall, indicating a diversity of dispersal rates. Generally, the ocean dispersal of age-1 fish was faster and more extensive than that of age-0 fish, with some age-1 fish migrating as fast as 10–40 km/d (0.5–3.0 body lengths/s). Within groups, interannual variation in dispersal was moderate. Identification of the distinct temporal and spatial ocean distribution patterns of juvenile salmon from Columbia River basin ESUs is important in order to evaluate the potential influence of changing ocean conditions on the survival and long term sustainability of these fish populations
Personalized diagnosis in suspected myocardial infarction
Background: In suspected myocardial infarction (MI), guidelines recommend using high-sensitivity cardiac troponin (hscTn)- based approaches. These require fixed assay-specific thresholds and timepoints, without directly integrating clinical information. Using machine-learning techniques including hs-cTn and clinical routine variables, we aimed to build a digital tool to directly estimate the individual probability of MI, allowing for numerous hs-cTn assays. Methods: In 2,575 patients presenting to the emergency department with suspected MI, two ensembles of machine-learning models using single or serial concentrations of six different hs-cTn assays were derived to estimate the individual MI probability ( ARTEMIS model). Discriminative performance of the models was assessed using area under the receiver operating characteristic curve (AUC) and logLoss. Model performance was validated in an external cohort with 1688 patients and tested for global generalizability in 13 international cohorts with 23,411 patients. Results: Eleven routinely available variables including age, sex, cardiovascular risk factors, electrocardiography, and hs-cTn were included in the ARTEMIS models. In the validation and generalization cohorts, excellent discriminative performance was confirmed, superior to hs-cTn only. For the serial hs-cTn measurement model, AUC ranged from 0.92 to 0.98. Good calibration was observed. Using a single hs-cTn measurement, the ARTEMIS model allowed direct rule-out of MI with very high and similar safety but up to tripled efficiency compared to the guideline- recommended strategy. Conclusion We developed and validated diagnostic models to accurately estimate the individual probability of MI, which allow for variable hs-cTn use and flexible timing of resampling. Their digital application may provide rapid, safe and efficient personalized patient care
Global Effect of Modifiable Risk Factors on Cardiovascular Disease and Mortality.
BACKGROUND: Five modifiable risk factors are associated with cardiovascular disease and death from any cause. Studies using individual-level data to evaluate the regional and sex-specific prevalence of the risk factors and their effect on these outcomes are lacking.
METHODS: We pooled and harmonized individual-level data from 112 cohort studies conducted in 34 countries and 8 geographic regions participating in the Global Cardiovascular Risk Consortium. We examined associations between the risk factors (body-mass index, systolic blood pressure, non-high-density lipoprotein cholesterol, current smoking, and diabetes) and incident cardiovascular disease and death from any cause using Cox regression analyses, stratified according to geographic region, age, and sex. Population-attributable fractions were estimated for the 10-year incidence of cardiovascular disease and 10-year all-cause mortality.
RESULTS: Among 1,518,028 participants (54.1% of whom were women) with a median age of 54.4 years, regional variations in the prevalence of the five modifiable risk factors were noted. Incident cardiovascular disease occurred in 80,596 participants during a median follow-up of 7.3 years (maximum, 47.3), and 177,369 participants died during a median follow-up of 8.7 years (maximum, 47.6). For all five risk factors combined, the aggregate global population-attributable fraction of the 10-year incidence of cardiovascular disease was 57.2% (95% confidence interval [CI], 52.4 to 62.1) among women and 52.6% (95% CI, 49.0 to 56.1) among men, and the corresponding values for 10-year all-cause mortality were 22.2% (95% CI, 16.8 to 27.5) and 19.1% (95% CI, 14.6 to 23.6).
Harmonized individual-level data from a global cohort showed that 57.2% and 52.6% of cases of incident cardiovascular disease among women and men, respectively, and 22.2% and 19.1% of deaths from any cause among women and men, respectively, may be attributable to five modifiable risk factors. (Funded by the German Center for Cardiovascular Research (DZHK); ClinicalTrials.gov number, NCT05466825.)
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