Electromagnetic vacuum fluctuations around a cosmic string in de Sitter spacetime

The electromagnetic field correlators are evaluated around a cosmic string in background of $(D+1)$-dimensional dS spacetime assuming that the field is prepared in the Bunch-Davies vacuum state. The correlators are presented in the decomposed form where the string-induced topological parts are explicitly extracted. With this decomposition, the renormalization of the local vacuum expectation values (VEVs) in the coincidence limit is reduced to the one for dS spacetime in the absence of the cosmic string. The VEVs of the squared electric and magnetic fields, and of the vacuum energy density are investigated. Near the string they are dominated by the topological contributions and the effects induced by the background gravitational field are small. In this region, the leading terms in the topological contributions are obtained from the corresponding VEVs for a string on the Minkowski bulk multiplying by the conformal factor. At distances from the string larger than the curvature radius of the background geometry, the pure dS parts in the VEVs dominate. In this region, for spatial dimensions $D>3$, the influence of the gravitational field on the topological contributions is crucial and the corresponding behavior is essentially different from that for a cosmic string on the Minkowski bulk. There are well-motivated inflationary models which produce cosmic strings. We argue that, as a consequence of the quantum-to-classical transition of super-Hubble electromagnetic fluctuations during inflation, in the postinflationary era these strings will be surrounded by large scale stochastic magnetic fields. These fields could be among the distinctive features of the cosmic strings produced during the inflation and also of the corresponding inflationary models.Comment: 19 pages, 2 figure

Electromagnetic vacuum densities induced by a cosmic string

We investigate the influence of a generalized cosmic string in (D+1) -dimensional spacetime on the local characteristics of the electromagnetic vacuum. Two special cases are considered with flat and locally de Sitter background geometries. The topological contributions in the vacuum expectation values (VEVs) of the squared electric and magnetic fields are explicitly separated. Depending on the number of spatial dimensions and on the planar angle deficit induced by the cosmic string, these contributions can be either negative or positive. In the case of the flat bulk, the VEV of the energy-momentum tensor is evaluated as well. For the locally de Sitter bulk, the influence of the background gravitational field essentially changes the behavior of the vacuum densities at distances from the string larger than the curvature radius of the spacetime.Comment: 19 pages, 5 figures. arXiv admin note: text overlap with arXiv:1706.0074

PROBLEMS RELATED TO PEDAGOGICAL SUPPORT SYSTEM OF CHILDREN WITH HEARING IMPAIRMENT OR DISORDERS IN REPUBLIC OF ARMENIA

In this article distinctive features related to the characteristic of children with hearing disorders due to story perception, teachers’ awareness level of research results related to mentioned problems, and some cultivated and justified approaches are presented. All researches are implemented in Republic of Armenian Tigranyan No 14 special school.In this article distinctive features related to the characteristic of children with hearing disorders due to story perception, teachers’ awareness level of research results related to mentioned problems, and some cultivated and justified approaches are presented. All researches are implemented in Republic of Armenian Tigranyan No 14 special school

COVID-19 Pandemic in German Humor

Verbal means of reflecting the situation of the coronavirus pandemic through the prism of German humor are considered. The relevance of the study is due to the interest of modern language science in the study of discourses as a kind of markers of linguistic consciousness and speech behavior. The novelty of the study lies in the fact that German humorous texts about the pandemic have not yet become the subject of a special scientific study. The purpose of the study is to describe and interpret the motives, reactions, assessments that represent the main areas of life that have changed during the pandemic. It is shown that the pandemic appears in jokes as a discursive space that predetermines and models a jokingly ironic assessment of the current situation: forced self-isolation served as a pretext for an ironic rethinking of marital, parent-child relationships, a public negative assessment of distance education is given, the state of some members of the society is comprehended as a mental illness. The representation of reality is constructed not without the influence of ethno-cultural factors and stereotypes: the German is comprehended and evaluated within the framework of the “own — different — alien” modus. The study can be continued as part of an interlingual description of humor during the coronavirus pandemic in order to study the linguocognitive, linguocultural aspects of language activity

Glycodelin as a possible marker of male fertility

This review summarizes the results of scientific research demonstrating the important role of determining serum and sperm glycodelin from men in couples with impaired fertility. It confirmed that necessary to establish the regional range of normal and pathological values.В обзоре обобщены результаты научных работ, свидетельствующих о важной роли определения гликоделина в сыворотке и эякуляте у супругов в парах с наррением фертильности. Подтверждается необходимость установления региональных диапазонов нормальных и патологических значений

Entangled light in transition through the generation threshold

We investigate continuous variable entangling resources on the base of two-mode squeezing for all operational regimes of a nondegenerate optical parametric oscillator with allowance for quantum noise of arbitrary level. The results for the quadrature variances of a pair of generated modes are obtained by using the exact steady-state solution of Fokker-Planck equation for the complex P-quasiprobability distribution function. We find a simple expression for the squeezed variances in the near-threshold range and conclude that the maximal two-mode squeezing reaches 50% relative to the level of vacuum fluctuations and is achieved at the pump field intensity close to the generation threshold. The distinction between the degree of two-mode squeezing for monostable and bistable operational regimes is cleared up.Comment: 7 pages, 4 figures; Content changed: more details added to the discussion. To be published in Phys. Rev.

The husband's role in miscarriage

Pregnancy loss in reproductive age couples is a growing clinical problem that needs adequate attention and investigation. The medical evaluation ot recurrent pregnancy loss to date has focused mainly on the female. The role of male factors ignored. Yet, the male contributes one-half of the genes for the embryo. The present paper reviews the current literature on the impact of male factor on pregnancy loss.Потеря беременности в парах репродуктивного возраста является растущей клинической проблемой, нуждающаяся в должном внимании и изучении. На современном зтапе медицинское обследование при привычном невынашивании беременности сосредоточено в основном на женщинах. Роль мужского фактора игнорируется. Тем не менее, мужчины обеспечивают половину генетического материала эмбриона. Данная статья является обзором современных литературных данных о вкладе мужского фактора в невынашивание беремености