496 research outputs found
Threshold of microvascular occlusion: injury size defines the thrombosis scenario
Damage to the blood vessel triggers formation of a hemostatic plug, which is
meant to prevent bleeding, yet the same phenomenon may result in a total
blockade of a blood vessel by a thrombus, causing severe medical conditions.
Here, we show that the physical interplay between platelet adhesion and
hemodynamics in a microchannel manifests in a critical threshold behavior of a
growing thrombus. Depending on the size of injury, two distinct dynamic
pathways of thrombosis were found: the formation of a nonocclusive plug, if
injury length does not exceed the critical value, and the total occlusion of
the vessel by the thrombus otherwise. We develop a mathematical model that
demonstrates that switching between these regimes occurs as a result of a
saddle-node bifurcation. Our study reveals the mechanism of self-regulation of
thrombosis in blood microvessels and explains experimentally observed
distinctions between thrombi of different physical etiology. This also can be
useful for the design of platelet-aggregation-inspired engineering solutions.Comment: 7 pages, 5 figures + Supplementary informatio
Transformation of the Concept of Administrative Liability in the Protection of the Rights, Legitimate Interests and Security of Citizens
This article discusses key areas of harmonization of administrative legislation and administrative responsibility between the Russian Federation and the Eurasian Economic Union (EAEU) countries. The most important issue in modern law is understanding that the uniform practical application of consistent administrative liability will enable the creation of a customs, tax, technological, and environmental space in the EAEU and BRICS. The author, on the basis of the findings of other researchers, gives an original definition of legal and administrative liability, which can be used in the harmonization of Russian legislation with the legislation of other BRICS and EAEU countries. The author also determines the regulation of the administrative process and the difference between administrative liability and other types of legal liability in accordance with modern Russian legislation
Анализ возможных путей снижения содержания серы в чугуне
One of the ways to increase the energy efficiency and intensity of blast furnace smelting, especially when using pulverized coal fuel, is to increase the hot strength of coke. In the conditions of OJSC NLMK, an oil additive was introduced into the coal charge to improve the coke quality. At the same time, sulfur content in the coke increases, and, consequently, sulfur content in the cast iron increases as well. In this regard, the task of finding ways to improve the desulfurization of cast iron in blast furnace becomes urgent. The main factors determining the desulfurization of cast iron are slag basicity, content of MgO oxide in it, temperature of the smelting products, and the slag viscosity. The purpose of this work was to compare the efficiency of sulfur removal by increasing the slag basicity and MgO content. On the basis of well-known equations, an algorithm was developed that allows the problem to be solved. It was established that an increase in MgO content in the slag promotes desulfurization of cast iron to a greater extent than a basicity increase. In addition, an increase in MgO content by 1 % is accompanied by an increase in slag yield by 3.0 – 3.5 kg/t of cast iron. At the same time, an increase in basicity by 0.01 leads to an increase in the slag yield by 4 – 5 kg/t of pig iron. Consequently, reducing the sulfur content in pig iron by increasing the slag basicity requires less heat. In terms of the specific consumption of coke, difference in heat demand is 0.4 – 0.5 kg/t of pig iron. It is shown that with an increase in MgO content in the slag, the slag viscosity at a temperature of 1450 °C increases to a lesser extent than with an increase in basicity. © 2020 National University of Science and Technology MISIS. All rights reserved
МОДУЛЬНЫЙ ГИБРИДНЫЙ МЕМЕТИЧЕСКИЙ АЛГОРИТМ ПОИСКА УСЛОВНОГО ГЛОБАЛЬНОГО ЭКСТРЕМУМА ФУНКЦИЙ МНОГИХ ПЕРЕМЕННЫХ
This paper presents a hybrid memetic algorithm for finding a conditional global extremum of functions. The algorithm combines such characteristics as modularity and adaptability which provides flexibility and controllability of the algorithm and reduces the influence of parameters. On the basis of the proposed algorithm the software complex is formed in the C# language. The method effectiveness is demonstrated on several well-known model examples of finding a conditional global extremum for functions of several variables.В работе предложен гибридный меметический алгоритм поиска условного глобального экстремума функций. Данный алгоритм сочетает в себе свойства модульности и адаптивности, что обеспечивает алгоритму гибкость, настраиваемость и позволяет уменьшить степень влияния параметров. На основе предложенного алгоритма реализован комплекс программ на языке C#. Его эффективность продемонстрирована на широко распространенных тестовых задачах поиска глобального условного экстремума функций многих переменных
ПРИМЕНЕНИЕ ГИБРИДНОГО МЕМЕТИЧЕСКОГО АЛГОРИТМА В ЗАДАЧАХ ОПТИМАЛЬНОГО УПРАВЛЕНИЯ НЕЛИНЕЙНЫМИ СТОХАСТИЧЕСКИМИ СИСТЕМАМИ С НЕПОЛНОЙ ОБРАТНОЙ СВЯЗЬЮ
The application of hybrid memetic algorithm of global constrained optimization in the search optimal control of nonlinear stochastic systems problem is researched in the paper. The suggested approach is based on control parametrization, which gives an opportunity to reduce the search optimal control problem to nonlinear programming problem. The global optimization memetic algorithm is suggested to solve the nonlinear programming problem. The term "memetic algorithms" is wildly used to denote method, which is based on evolutional, cultural-evolutional or another approach, that uses notions like population and individual learning process or other local improvement procedure to determine global extremum. In the developed algorithm the cultural evolution component is implemented by means of the solution of sub-task optimization using ant colony method or simulated annealing algorithm. Herewith mems (unit of cultural information) are used to generate perfect individual. Several alternative forms of parametrization are considered: in the form of expansion by Legendre polynomials system and in the form of cosine-waves. The efficiency of the proposed algorithms was analyzed by means of created software complex. The problem of damping rotational satellite motion by means of installed engine was solved as the example. Verification of obtained results using the solution detected with local variations method was done. The described results show the sufficient efficiency level and reflect the necessity of further research in this direction. В работе исследуется применение гибридного меметического алгоритма глобальной условной оптимизации в задаче поиска оптимального управления нелинейными стохастическими системами. Предлагаемый подход основывается на параметризации искомого управления, что позволяет свести задачу поиска оптимального управления к задаче нелинейного программирования. Решение последней предлагается искать с помощью метаэвристического алгоритма глобальной оптимизации – меметического алгоритма. Термин меметические алгоритмы широко используется в качестве обозначения взаимодействия эволюционного, культурно-эволюционного или другого подхода, основанного на понятии популяции, и индивидуального обучения особей либо другой локальной процедуры улучшения для решения задач поиска глобального экстремума. В разработанном алгоритме культурная эволюционная составляющая реализуется в ходе решения подзадачи оптимизации любым из двух методов: с помощью метода муравьиных колоний или метода имитации отжига. При этом в ходе культурной эволюции мемы (единицы передачи культурной информации) используются для генерации более совершенной (в терминах решаемой задачи – более эффективной) особи. В данном исследовании рассматривается несколько альтернативных способов параметризации управления: в виде разложения по системе полиномов Лежандра и косинусоид. Эффективность предложенных алгоритмов исследована с помощью созданного комплекса программ. В качестве тестового примера использована задача гашения вращательного движения спутника с помощью установленных на нем двигателей. О корректности решений, полученных с помощью предложенного подхода, можно судить путем сравнения с решением, найденным с помощью метода локальных вариаций. Полученные данные позволяют говорить о достаточной эффективности предложенного подхода.
Avifauna at the Neolithic Sites of the Dnieper-Dvina Basin: the role of birds in the culture of ancient hunter-gatherers of the VI–III Millennium BC
The article presents a study of avifauna at the Neolithic sites of the Dnieper-Dvina basin (Serteya I and II sites). Changes of paleo-environmental conditions and biotopes, archaeological cultures and types of campsites might have determined changes in the cultural and economic model of the ancient population, having an influence on avifauna particularity in different time periods. Four biotopic groups of birds: near-water birds, woodside birds, forest and meadow-steppe birds are singled out. Birds from the near-water group dominate. It can be assumed, that birds played an important role in food ration in spring and autumn. Paleo-ecological studies allow us to reconstruct a change of water body types. That may have caused a change in bird species. Changes in bird nesting and migration areas may also be evidence of paleo-ecological changes in the V–III millennium BC. Despite the widespread practice of making tools and ornaments from bones and animals teeth at the Neolithic sites in Dnieper-Dvina basin, bird bones were used rather seldom. Almost the entire collection dates back to the end of IV–III millennium BC and is represented mainly by tube beads and blanks
Application of modern immunological methods in the diagnosis of tuberculosis in HIV-infected patients
Combination of TB and HIV-infection is still the most nowadays important problem, and it connects not only with steady growth of HIV infection, but with difficulties in TB diagnosis. X-ray lung studies often have unusual nature, clinical symptomatology appears when process are hard and spread. At the same time in global practice IGRAtests applying, to which they belong to SPOT.TB test and QuantiFERON®-TB Gold test, they pay great attention to it, particularly among patients with HIV- infection. In study there were data when 41 patients with lung TB were examined, 56 HIV-positive patients with lung TB and 58 healthy donors. When active TB IGRA-test and test with Diaskin test show comparable same results. Against the backdrop of HIV skin tests (Mantoux test with 2 TE and tests with Diaskin test) it was demonstrated direct dependence of level immunosuppression in contrast to IGRA – tests, that allows to carry out these researches in conditions when standard skin tests do not work
- …