Stable multiple-charged localized optical vortices in cubic-quintic nonlinear media

The stability of two-dimensional bright vortex solitons in a media with focusing cubic and defocusing quintic nonlinearities is investigated analytically and numerically. It is proved that above some critical beam powers not only one- and two-charged but also multiple-charged stable vortex solitons do exist. A vortex soliton occurs robust with respect to symmetry-breaking modulational instability in the self-defocusing regime provided that its radial profile becomes flattened, so that a self-trapped wave beam gets a pronounced surface. It is demonstrated that the dynamics of a slightly perturbed stable vortex soliton resembles an oscillation of a liquid stream having a surface tension. Using the idea of sustaining effective surface tension for spatial vortex soliton in a media with competing nonlinearities the explanation of a suppression of the modulational instability is proposed.Comment: 4 pages, 3 figures. Submitted to Journal of Optics A. The proceedings of the workshop NATO ARW, Kiev 2003 Singular Optics 200

New types of stable nonlinear whistler waveguides

International audienceThe stationary self-focusing of whistler waves with frequencies near half of the electron-cyclotron frequency in the ionospheric plasma is considered in the framework of a two-dimensional generalized nonlinear Schrödinger equation including fourth-order dispersion effects and nonlinearity saturation. New types of soliton-like (with zero topological charge) and vortex-like nonlinear waveguides are found, and their stability confirmed both analytically and numerically

Effect of frictional treatment on the microstructure and surface properties of low-carbon steel

The microstructure of annealed low-carbon (0.17 wt% C) steel subjected to frictional treatment with a sliding hard-alloy indenter is studied by EBSD analysis, as well as its micromechanical characteristics. It has been found that frictional treatment results in high dispersity of the structure in the steel surface, down to the submicro- and nanocrystalline state. Instrumented microindentation has revealed that, under all the loads, the values of the contact elastic modulus E ∗ of low-carbon (0.17 wt% C) steel after frictional treatment are lower than those in the initial annealed state. Particularly, the mean value of E ∗ decreases from 208 to 168 GPa under a load of 1 gf on the indenter, from 213 to 176 GPa under a load of 25 gf and from 204 to 155 GPa under a load of 200 gf. It is for the first time that the effect of a decrease in the elastic modulus is observed for a carbon steel subjected to frictional treatment. It also follows from the microindentation data that frictional treatment increases the capability of the surface of annealed low-carbon (0.17 wt% C) steel to withstand higher contact loads prior to plastic deformation. © 2018 Author(s)

To the question of the level of readiness and the degree of motivation of the student of the pedagogical higher education institution to professional activity

The article deals with the problem of the level of professional readiness of the student to work in conjunction with the level of his motivation. These multifactorial processes interdepend each otherВ статье рассматривается проблема уровня профессиональной готовности студента к деятельности во взаимосвязи с уровнем его мотивированности. Эти многофакторные процессы взаимообуславливают друг друг

Stability of two-dimensional spatial solitons in nonlocal nonlinear media

We discuss existence and stability of two-dimensional solitons in media with spatially nonlocal nonlinear response. We show that such systems, which include thermal nonlinearity and dipolar Bose Einstein condensates, may support a variety of stationary localized structures - including rotating spatial solitons. We also demonstrate that the stability of these structures critically depends on the spatial profile of the nonlocal response function.Comment: 8 pages, 9 figure

Effect of antibodies to glutamate on age-related memory changes in C57Bl/6 mice

Chronic intranasal administration of antibodies to glutamate to aging C57Bl/6 mice improved passive avoidance conditioning, had no effect on horizontal and vertical locomotor activity, but slowed locomotion in the open-field test. Administration of antibodies to glutamate increased the content of dopamine and its metabolites in mouse hippocampus, but had no effect on the metabolism of neurotransmitter amino acids. In the frontal cortex, antibodies to glutamate did not affect neurotransmitter metabolism, but increased the level of both excitatory and inhibitory amino acids without changing their ratio

Effects of antibodies to glutamate on cerebral expression of the Tnfrsf1A gene under conditions of spatial amnesia induced by proinflammatory protein S100A9 fibrils in aging mice

Proinflammatory S100A9 protein is a promoter of inflammation-linked neurodegeneration and the Tnfrsf1A gene encodes the TNF receptor 1A that binds TNFα to function as a regulator of inflammation. We studied the effects of chronic intranasal administration of in vitro prepared S100A9 fibrils alone or in combination with anti-glutamate antibodies on the expression of the Tnfrsf1A gene in the hippocampus, prefrontal cortex, and cerebellum of aging C57BL/6 mice under conditions of impaired spatial memory. A differential cerebral pattern of Tnfrsf1A gene activity and its modification by S100A9 fibrillar structures were observed: inhibition of Tnfrsf1A gene expression in the hippocampus and cerebellum and its activation in the prefrontal cortex. Anti-glutamate antibodies normalized the expression of the Tnfrsf1A gene in the prefrontal cortex by affecting the TNF signaling pathway and preventing the development of inflammation

Youth Subcultures as a Social Phenomenon

The article deals with the features of youth subcultures, their place in society, interaction with the common culture of the causes of formation, the role in the lives of young people. Examples of youth subcultures that emerged in the West and in Russia in the XX century are given.В статье рассматриваются особенности молодёжных субкультур, их место в обществе, взаимодействие с общепринятой культурой, причины формирования, роль в жизни молодых людей. Приводятся примеры молодёжных субкультур, возникших на Западе и в России в XX веке

Assessment of the biological value of forages according to the control tests of milk and its use in the organization of feeding of dairy cattle

The article presents the results of the assessment of the biological usefulness of feed according to the control tests of milk. Scientific research was carried out in LLC "Minskoye" of the Kostroma district of the Kostroma region on a population of 369 cows of the Kostroma and Black-and-White breeds according to the seasons of the year. The authors found that in terms of the level of digestible protein in lactating cows, there is an imbalance in almost all seasons of the year, so most animals are prone to diseases associated with metabolic disorders. The level of rumen acidity in animals of the Koroma breed was more stable (pH = 6.2-6.4) in all seasons of the year, which indicates a lower likelihood of developing acidosis, in contrast to Black-and-White breed cows. Based on the indicators of milk control tests, insufficient supply of raw protein to cows of the Kostroma and Black-and-White breeds during the milking period was established. The highest daily milk yields (more than 30 kg of milk) were obtained from cows in the first and second periods of lactation in all seasons of the year. In animals with a level of availability of digestible protein of 10.3-10.9 g/MJ, there is a normal ratio of fat: protein (1.26:1), with a profitability level of 66.11%, while animals with an insufficient level availability of digestible protein of 10.2 g/MJ and less, had the level of profitability of milk production 73.93 and 86.44%, respectively. When the level of availability of digestible protein is more than 11.0 g/MJ in animals, the likelihood of acidosis increases. Evaluation of the biological value of feeds according to control tests of milk during the period of control milkings will allow monitoring the energy and protein nutrition of animals