Thermal non-equilibrium effects in quantum reflection

We show that the quantum reflection coefficient of ultracold heavy atoms scattering off a dielectric surface can be tuned in a wide range by suitable choice of surface and environment temperatures. This effect results from a temperature dependent long-range repulsive part of the van der Waals-Casimir-Polder-Lifshitz atom-surface interaction potential

Optical and evaporative cooling of cesium atoms in the gravito-optical surface trap

We report on cooling of an atomic cesium gas closely above an evanescent-wave atom mirror. At high densitities, optical cooling based on inelastic reflections is found to be limited by a density-dependent excess temperature and trap loss due to ultracold collisions involving repulsive molecular states. Nevertheless, very good starting conditions for subsequent evaporative cooling are obtained. Our first evaporation experiments show a temperature reduction from 10muK down to 300nK along with a gain in phase-space density of almost two orders of magnitude.Comment: 8 pages, 6 figures, submitted to Journal of Modern Optics, special issue "Fundamentals of Quantum Optics V", edited by F. Ehlotzk

Taking into account the age of students in the teaching of translation

Целью данной статьи является рассмотрение возрастных особенностей, которые необходимо учитывать педагогу в процессе обучения иностранному языку учащихся разных возрастных групп. В статье представлены трудности, испытываемые учащимися в процессе овладения навыком перевода, описаны некоторые методические приемы для обучения переводу учащихся разных возрастных групп, а также показано значение мотивации для учащихся в процессе овладения иностранным языком и способами перевода.The article studies age characteristics which are meaningful in the process of foreign language teaching. Challenges that learners face while acquiring translation skills are highlighted. Some techniques of translation teaching in the situations of specific age groups are described. The importance of learner's motivation for language acquisition and translation skills acquisition is in the focus

Attractiveness of the Russian regional space as a living environment: Aspect of the migrants' behavioural rationality

This study focuses on the rationality of the migrants' behaviour. We hypothesise that the migration growth rate depends on the territory attractiveness for living. The rational behaviour is defined as the direct dependence of the migrations on the characteristics of the territory attractiveness. The irrational behaviour means that the reverse dependence is present. The direct dependence is recognised if the level of the migrants' positive reactions to the factors of the territory attractiveness is no less than 30 % from the maximum. 83 subjects of the Russian Federation were clustered based on 12 objective characteristics of the life's quality. We distinguished the largest Middle Cluster, which includes 56 regions. Further we transformed the panel data for the period from 2005 to 2015 into the array of the coefficients of correlations between the characteristics of the territory attractiveness and the migration growth rates in the regions. Using these characteristics, the regions were clustered again. The regional types of the Middle cluster with the rational and irrational behaviours include 22 regions each. The level of the migrants' positive reactions to the factors of the territory attractiveness is 44.1 % for the first (rational) regional type and 42.5 % for the second (irrational) type. The regional type with the indifferent behaviour includes 12 regions. The level of the migrants' reactions to the characteristics of these territory attractiveness is just 5.8 %. Based on the regression models of the migration coefficient for each cluster type, we have provided recommendations for managing the migration flows using the differential approach. © 2019 Petrov M. B., Kurushina E. V., Druzhinina I. V. Text

Xenon isotopes in Archean and Proterozoic insoluble organic matter: a robust indicator of syngenecity?

Insoluble organic materials (kerogens) isolated from ancient sedimentary rocks provide unique insights into the evolution of early life. However, establishing whether these kerogens are indeed syngenetic with the deposition of associated sedimentary host rocks, or contain contribution from episodes of secondary deposition, is not straightforward. Novel geochemical criterions are therefore required to test the syngenetic origin of Archean organic materials. On one hand, the occurrence of mass-independent fractionation of sulphur isotopes (MIF-S) provides a tool to test the Archean origin of ancient sedimentary rocks. Determining the isotope composition of sulphur within kerogens whilst limiting the contribution from associated minerals (e.g., nano-pyrites) is however challenging. On the other end, the Xe isotope composition of the Archean atmosphere has been shown to present enrichments in the light isotopes relative to its modern composition, together with a mono-isotopic deficit in ¹²⁹Xe. Given that the isotopic composition of atmospheric Xe evolved through time by mass dependent fractionation (MDF) until ∼2.5-2.0 Ga, the degree of MDF of Xe isotopes trapped in kerogens could provide a time stamp for the last chemical equilibration between organic matter and the atmosphere. However, the extent to which geological processes could affect the signature of Xe trapped in ancient kerogen remains unclear. In this contribution, we present new Ar, Kr and Xe isotopic data for four kerogens isolated from 3.4 to 1.8 Gy-old cherts and confirm that Xe isotopes from the Archean atmosphere can be retained within kerogens. However, new Xe-derived model ages are lower than expected from the ages of host rocks, indicating that initially trapped Xe components were at least partially lost and/or mixed together with some Xe carried out by younger generations of organic materials, therefore complicating the Xe-based dating method. Whilst non-null Δ³³S values and ¹²⁹Xe deficits relative to modern atmosphere constitute reliable imprints from the Archean atmosphere, using Xe isotopes to provide information on the syngenetic origin of ancient organic matter appears to be a promising - but not unequivocal - tool that calls for further analytical development

Website as a Tool for Creating University Image

The article analyzes the trends manifested in the spheres of the Internet site of higher education institutions. The paper emphasizes the role of the Internet site of the University in achieving the sociopragmatic purpose of information texts of the University on educational programs.В статье анализируются тенденции, проявившиеся в сферах Интернет-сайт вузов. В работе подчеркивается роль Интернет-сайт вуза в достижении социопрагматической цели информационных текстов вуза в реализуемых образовательных программах

Sleep features in menopausal women (literature review)

The article reviews the literature of domestic and foreign researchers devoted to the somnological aspects of the menopausal period in women. Age-related changes in the structural organization of sleep are shown with a deficiency of sex steroids, also and in the gender aspect. A high frequency of sleep disorders in menopausal women, reaching 60 %, has been revealed. However, the results of studies on complaints of sleep disorders depending on the climacteric phase are ambiguous, which may be due to ethnicity. Data on some pathogenetic mechanisms of the formation of the most frequent sleep disorders in menopausal women - insomnia, obstructive sleep apnea syndrome and fibromyalgia - are described. The results of polysomnography in these pathological states are presented, indicating a decrease in sleep efficiency, a change in its "architecture", and a longer waking time during the night with insomnia; a significant increase in the apnea/hypopnea index, a delay in the phase of fast sleep, a decrease in the duration of deep stages of sleep and a decrease in its effectiveness - in obstructive sleep apnea syndrome. The social and medical consequences of sleep disorders and their comorbidity with such pathological conditions as mental disorders, obesity, cardiovascular diseases, oncology, disorders of carbohydrate metabolism, bronchial asthma, mortality are noted

Towards surface quantum optics with Bose-Einstein condensates in evanescent waves

We present a surface trap which allows for studying the coherent interaction of ultracold atoms with evanescent waves. The trap combines a magnetic Joffe trap with a repulsive evanescent dipole potential. The position of the magnetic trap can be controlled with high precision which makes it possible to move ultracold atoms to the surface of a glass prism in a controlled way. The optical potential of the evanescent wave compensates for the strong attractive van der Waals forces and generates a potential barrier at only a few hundred nanometers from the surface. The trap is tested with Rb Bose-Einstein condensates (BEC), which are stably positioned at distances from the surfaces below one micrometer

Ivermectin: Evaluation of Efficacy and Safety in COVID-19

The search for an effective and safe COVID-19 therapy involves, among other things, assessment of efficacy of medicines already used for the treatment of other diseases, and having potential antiviral activity against SARS-CoV-2. The relevance of the presented study stems from ambiguous data on the off-label use of the antiparasitic medicine ivermectin for the treatment of COVID-19 patients. The aim of the study was to analyse ivermectin efficacy and safety for COVID-19 treatment, as reflected in the scientific literature. Ivermectin, an antiparasitic medicine from the group of macrocyclic lactones produced by Streptomyces avermitilis, stimulates release of the inhibitory neurotransmitter gamma-aminobutyric acid, which leads to impaired transmission of nerve impulses, paralysis and death of parasites. The results of preclinical studies show ivermectin’s inhibitory activity against a number of RNA and DNA viruses, including SARS-CoV-2. The results of ivermectin clinical studies are ambiguous: a number of studies demonstrated a positive effect on the condition of COVID-19 patients, however, there is currently no convincing evidence of the validity and efficacy of ivermectin use for the prevention and treatment of COVID-19 patients. The safety profile of ivermectin is relatively favourable. Large randomised controlled trials are needed to fully assess the feasibility of using ivermectin in COVID-19