Rapid directional alignment of velocity and magnetic field in magnetohydrodynamic turbulence

We show that local directional alignment of the velocity and magnetic field fluctuations occurs rapidly in magnetohydrodynamics for a variety of parameters. This is observed both in direct numerical simulations and in solar wind data. The phenomenon is due to an alignment between the magnetic field and either pressure gradients or shear-associated kinetic energy gradients. A similar alignment, of velocity and vorticity, occurs in the Navier Stokes fluid case. This may be the most rapid and robust relaxation process in turbulent flows, and leads to a local weakening of the nonlinear terms in the small scale vorticity and current structures where alignment takes place.Comment: 4 pages, 6 figure

Polymorphism of gene of IL-8 cytokine in acute pancreatitis complicated with peritonitis

This study has assessed the possible association of IL-8 (-251А/Т) polymorphism with clinical course of pancreatogenic peritonitis and suggests that the identification of genetic polymorphism of IL-8 (-251A/T) may be informative and serve as an additional criterion to predict both the clinical course and outcome of pancreatogenic peritonitis.Te studium zostało przeprowadzone w celu określenia możliwego związku miedzy genetycznym polimorfem cytokiny IL-8 (-251А/Т), a jego wpływu na warianty klinicznego przebiegu ostrego zapalenia trzustki, skomplikowanego zapaleniem otrzewnej i może dostarczać informacyji i służyć jak dodatkowe kryterium prognozowania

Деякі аспекти підготовки фахівців з радіотехніки в сучасних умовах

The problem of experts preparing in radio engineering specialists' in modem environment has been discussed. The education plan is analysed and the improvement ways of experts preparing is proposed.Обсуждаются проблемы подготовки специалистов направления радиотехники в современных условиях. Анализируется содержание учебного плана, предлагаются пути улучшения подготовки специалистов.Обговорюються проблеми підготовки фахівців напряму радіотехніка в сучасних умовах. Аналізується наведений навчальний план, пропонуються шляхи покращення підготовки фахівців

Magnetic Reconnection As An Element Of Turbulence

In this work, recent advances on the study of reconnection in turbulence are reviewed. Using direct numerical simulations of decaying incompressible two-dimensional magnetohydrodynamics (MHD), it was found that in fully developed turbulence complex processes of reconnection locally occur (Servidio et al., 2009, 2010a). In this complex scenario, reconnection is spontaneous but locally driven by the fields, with the boundary conditions provided by the turbulence. Matching classical turbulence analysis with a generalized Sweet-Parker theory, the statistical features of these multiple-reconnection events have been identified. A discussion on the accuracy of our algorithms is provided, highlighting the necessity of adequate spatial resolution. Applications to the study of solar wind discontinuities are reviewed, comparing simulations to spacecraft observations. New results are shown, studying the time evolution of these local reconnection events. A preliminary study on the comparison between MHD and Hall MHD is reported. Our new approach to the study of reconnection as an element of turbulence has broad applications to space plasmas, shedding a new light on the study of magnetic reconnection in nature

Spatio-temporal behavior of magnetohydrodynamic fluctuations with cross-helicity and background magnetic field

We study the spatiotemporal behavior of the Elsässer variables describing magnetic and velocity field fluctuations, using direct numerical simulations of three-dimensional magnetohydrodynamic turbulence. We consider cases with relatively small, intermediate, and large values of a mean background magnetic field and with null, small, and high cross-helicity (correlations between the velocity and the magnetic field). Wavenumber-dependent time correlation functions are computed for the different simulations. From these correlation functions, the decorrelation time is computed and compared with different theoretical characteristic times: the local nonlinear time, the random-sweeping time, and the Alfvénic time. It is found that decorrelation times are dominated by sweeping effects for low values of the mean magnetic field and for low values of the cross-helicity, while for large values of the background field or of the cross-helicity and for wave vectors sufficiently aligned with the guide field, decorrelation times are controlled by Alfvénic effects. Finally, we observe counterpropagation of Alfvénic fluctuations due to reflections produced by inhomogeneities in the total magnetic field. This effect becomes more prominent in flows with large cross-helicity, strongly modifying the propagation of waves in turbulent magnetohydrodynamic flows.Fil: Lugones, Rodrigo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Dmitruk, Pablo Ariel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Mininni, Pablo Daniel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Pouquet, A.. University of Colorado; Estados UnidosFil: Matthaeus, W. H.. University of Colorado; Estados Unido

Polymorphism of gene of IL-8 cytokine in acute pancreatitis complicated with peritonitis

This study has assessed the possible association of IL-8 (-251А/Т) polymorphism with clinical course of pancreatogenic peritonitis and suggests that the identification of genetic polymorphism of IL-8 (-251A/T) may be informative and serve as an additional criterion to predict both the clinical course and outcome of pancreatogenic peritonitis.Te studium zostało przeprowadzone w celu określenia możliwego związku miedzy genetycznym polimorfem cytokiny IL-8 (-251А/Т), a jego wpływu na warianty klinicznego przebiegu ostrego zapalenia trzustki, skomplikowanego zapaleniem otrzewnej i może dostarczać informacyji i służyć jak dodatkowe kryterium prognozowania

БОРТОВОЙ МИКРОМОДУЛЬ РАСПОЗНАВАНИЯ ЦЕЛЕВЫХ КЛАССОВ ИЗОБРАЖЕНИЙ В СИСТЕМАХ МОНИТОРИНГА: МЕТОДЫ И АЛГОРИТМЫ

The methods and algorithms of a compact on-board image recognition module to be used as a part of monitoring systems is presented. The main goal of the module is significantly reduction in the amount of image and video data, which should be stored on board and/or transmitted to a surface station. This is achieved by way of real-time recognition of frames of input video sequence and pre-selection of those similar to the given target image classes. It is supposed the module can be used as a part of remote monitoring systems based on drones and small-size satellites.Рассматриваются методы и алгоритмы функционирования бортового микромодуля для оперативного распознавания целевых классов изображений земной поверхности в системах мониторинга природных и техногенных объектов. Основной задачей микромодуля является существенное сокращение объема накапливаемых и/или передаваемых на землю видеоданных за счет оперативного решения задачи распознавания изображений подстилающей поверхности, поступающих с фото- и видеокамер. Разрабатываемый микромодуль может быть использован в системах мониторинга, построенных на основе беспилотных летательных аппаратов и малых космических аппаратов