81 research outputs found

    On the contribution of cosmic-ray interactions in the circumgalactic gas to the observed high-energy neutrino flux

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    Cosmic rays escaping the Milky-Way disk interact with circumgalactic gas which fills the virial volume of our Galaxy. These interactions should produce guaranteed fluxes of energetic diffuse neutrinos and photons observable at the Earth. This neutrino flux would be a plausible contribution to the spectrum measured by the IceCube neutrino observatory: the energy emitted in this way is weakly constrained from cascade gamma rays, since the cascades have no time to develop, but the arrival directions of the neutrinos do not point to the Galactic disk, in agreement with observations. However, previous studies reported very different estimates of the corresponding neutrino flux, so it was unclear if this contribution to the observed spectrum is essential. Here we readdress the calculation of this diffuse neutrino flux component under various assumptions about the cosmic-ray spectrum and propagation in the circumgalactic medium. We find that even with these variations, this contribution to the observed neutrino flux remains subleading provided multimessenger constraints are satisfied.Comment: 19 pages, 6 figures; v2: discussions extended; version accepted by JCA

    FUNCTIONAL STATUS OF ATHLETS ANALYSIS UNDER THE ADAPTATION TO THE CYCLIC KIND OF SPORTS TRAINING LOADS

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    Непрерывное повышение спортивной результативности предъявляет всевозрастающие требования к качеству тренировочного процесса. Его совершенствование зависит от наличия устойчивой обратной связи между тренировочными воздействиями и адекватной реакцией на них организма спортсмена. В статье рассматриваются подходы комплексного исследования функционального состояния, на основе изучения его отдельных компонентов, в процессе подготовки юных лыжников и конькобежцев.Цель. Статья посвящена актуальному вопросу в работе тренеров – оценка функционального состояния организма юных спортсменов на основе изучения психического, нейродинамического, энергетического и двигательного компонентов.Метод и методология проведения работы. Основу исследования составляют:– тест «Простая зрительно-моторная реакция» (ПЗМР) до физической нагрузки и после нагрузки, характеризующий уровень возбудимости ЦНС и скорости распространения возбуждения по нервным цепям;– тест «Критическая частота слияния мельканий» (КЧСМ) до физической нагрузки и после нагрузки,– тест «Устойчивость корковых процессов» (УКП),Изучение функционального состояния ЦНС осуществлялось с помощью аппаратно-программного комплекса «НС-психотест», включающего программное обеспечение для IBM PC под управлением Windows и внешний высокоточный контроллер. Для оценки психического компонента исследовалось логическое мышление, внимание (таблица Шульта-Платонова) и память.Энергетический компонент исследовался с помощью теста Руфье.Результаты. Результат работы заключается в том, что выбор указанных методик определения функционального состояния спортсменов является оправданным, так как выявлены различия в исследуемых компонентов функционального состояния лыжников и конькобежцев. Это обусловлено различием спортивных специализаций, в каждой из которых механизмы энергетического обеспечения двигательных режимов различаются.Область применения результатов. Результаты исследования важны для организаторов тренировочного процесса молодых атлетов в циклических видах спорта. Данное исследование может послужить дальнейшему совершенствованию тренировочного процесса в циклических видах спорта.Continuous athletic performance enhancement makes higher demands on work-out session quality. Its advance depends on the presence of a stable feedback between training manipulations and adequate sportsman body response to those. This paper presents various approaches to multicenter study of functional status, following the study of its separate components, during the training preparation of young ski-racers and speed skaters.Purpose. The article is concerned with the topic of coach-instructor interest – functional status of young athletes in respect to analysis of psychic, neurodynamic, energy and physical elements.Methodology. Methodological foundations of the research:– «Simple visual-motor reaction» test (SVMR) before and after muscle loading representative of SVMR driving level and its spreading speed over neurological circuit;– «Critical flicker fusion frequency» test (CFFF) before and after muscle loading;– «Cortical processes stability» test (CPS).Functional status CPS analysis was investigated under hardware and software complex «PS-psychotest», which includes IBM PC software for Windows and external high-accuracy controller. Psychic element was investigated through logical thinking, attentiveness (Schulte table) and memory.Energy element was investigated under the Ruffier functional test.Results. Research results center around the fact that the choice of required methods of functional status of athletes analysis appears appropriate as therefore functional status of ski-racers and speed skaters elements of interest were exposed to differ. This is due to the fact that the sportive areas of specialization differ owing to different physical condition energy provision dynamics.Practical implications. The results of the research are considered important for cyclic sports young athletes workout-session instructors. The present research can be useful for future advancing of cyclic sports workout-sessions

    Direct imaging of shock wave splitting in diamond at Mbar pressure

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    Understanding the behavior of matter at extreme pressures of the order of a megabar (Mbar) is essential to gain insight into various physical phenomena at macroscales—the formation of planets, young stars, and the cores of super-Earths, and at microscales—damage to ceramic materials and high-pressure plastic transformation and phase transitions in solids. Under dynamic compression of solids up to Mbar pressures, even a solid with high strength exhibits plastic properties, causing the induced shock wave to split in two: an elastic precursor and a plastic shock wave. This phenomenon is described by theoretical models based on indirect measurements of material response. The advent of x-ray free-electron lasers (XFELs) has made it possible to use their ultrashort pulses for direct observations of the propagation of shock waves in solid materials by the method of phase-contrast radiography. However, there is still a lack of comprehensive data for verification of theoretical models of different solids. Here, we present the results of an experiment in which the evolution of the coupled elastic–plastic wave structure in diamond was directly observed and studied with submicrometer spatial resolution, using the unique capabilities of the x-ray free-electron laser (XFEL). The direct measurements allowed, for the first time, the fitting and validation of the 2D failure model for diamond in the range of several Mbar. Our experimental approach opens new possibilities for the direct verification and construction of equations of state of matter in the ultra-high-stress range, which are relevant to solving a variety of problems in high-energy-density physics

    Modification of Biocorrosion and Cellular Response of Magnesium Alloy WE43 by Multiaxial Deformation

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    The study shows that multiaxial deformation (MAD) treatment leads to grain refinement in magnesium alloy WE43. Compared to the initial state, the MAD-processed alloy exhibited smoother biocorrosion dynamics in a fetal bovine serum and in a complete cell growth medium. Examination by microCT demonstrated retardation of the decline in the alloy volume and the Hounsfield unit values. An attendant reduction in the rate of accumulation of the biodegradation products in the immersion medium, a less pronounced alkalization, and inhibited sedimentation of biodegradation products on the surface of the alloy were observed after MAD. These effects were accompanied with an increase in the osteogenic mesenchymal stromal cell viability on the alloy surface and in a medium containing their extracts. It is expected that the more orderly dynamics of biodegradation of the WE43 alloy after MAD and the stimulation of cell colonization will effectively promote stable osteosynthesis, making repeat implant extraction surgeries unnecessary

    Rationale for Processing of a Mg-Zn-Ca Alloy by Equal-Channel Angular Pressing for Use in Biodegradable Implants for Osteoreconstruction

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    Widespread use of Mg-Zn-Ca alloys in clinical orthopedic practice requires improvement of their mechanical properties—in particular, ductility—and enhancement of their bioactivity for accelerated osteoreconstruction. The alloy was studied in two structural states: after homogenization and after equal-channel angular pressing. Immersion and potentiodynamic polarization tests showed that the corrosion rate of the alloy was not increased by deformation. The mass loss in vivo was also statistically insignificant. Furthermore, it was found that deformation did not compromise the biocompatibility of the alloy and did not have any significant effect on cell adhesion and proliferation. However, an extract of the alloy promoted the alkaline phosphatase activity of human mesenchymal stromal cells, which indicates osteogenic stimulation of cells. The osteoinduction of the deformed alloy significantly exceeded that of the homogenized one. Based on the results of this work, it can be concluded that the alloy Mg-1%Zn-0.3%Ca modified by equal-channel angular pressing is a promising candidate for the manufacture of biodegradable orthopedic implants since it stimulates osteogenic differentiation and has greater ductility, which provides it with a competitive advantage in comparison with the homogenized state

    The Forest Observation System, building a global reference dataset for remote sensing of forest biomass

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    International audienceForest biomass is an essential indicator for monitoring the Earth's ecosystems and climate. It is a critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies such as REDD+, among others. Wall-to-wall mapping of aboveground biomass (aGB) is now possible with satellite remote sensing (RS). However, RS methods require extant, up-to-date, reliable, representative and comparable in situ data for calibration and validation. Here, we present the Forest Observation System (FOS) initiative, an international cooperation to establish and maintain a global in situ forest biomass database. aGB and canopy height estimates with their associated uncertainties are derived at a 0.25 ha scale from field measurements made in permanent research plots across the world's forests. all plot estimates are geolocated and have a size that allows for direct comparison with many RS measurements. The FOS offers the potential to improve the accuracy of RS-based biomass products while developing new synergies between the RS and ground-based ecosystem research communities

    Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

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    Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

    The robust multigrid technique: for black-box software

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    Black-Box Solver for Numerical Simulations and Mathematical Modelling in Engineering Physics

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    This article presents a two-grid approach for developing a black-box iterative solver for a large class of real-life problems in continuum mechanics (heat and mass transfer, fluid dynamics, elasticity, electromagnetism, and others). The main requirements on this (non-)linear black-box solver are: (1) robustness (the lowest number of problem-dependent components), (2) efficiency (close-to-optimal algorithmic complexity), and (3) parallelism (a parallel robust algorithm should be faster than the fastest sequential one). The basic idea is to use the auxiliary structured grid for more computational work, where (non-)linear problems are simpler to solve and to parallelize, i.e., to combine the advantages of unstructured and structured grids: simplicity of generation in complex domain geometry and opportunity to solve (non-)linear (initial-)boundary value problems by using the Robust Multigrid Technique. Topics covered include the description of the two-grid algorithm and estimation of their robustness, convergence, algorithmic complexity, and parallelism. Further development of modern software for solving real-life problems justifies relevance of the research. The proposed two-grid algorithm can be used in black-box parallel software for the reduction in the execution time in solving (initial-)boundary value problems
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