Highly viscous electron fluid in GaAs quantum wells

A fluid in which shear-stress transverse waves, being character for solids, can propagate is usually referred as a highly viscous fluid. Hydrodynamics of the fluid formed by conduction electrons has been recently discovered in graphene, ultra-pure Weyl and layered metals, and high-mobility GaAs quantum wells. Here we construct a theory of magnetotransport in a highly viscous two-dimensional (2D) electron fluid in moderate magnetic fields, accounting its viscoelastic dynamics and the memory effects in the interparticle scattering. In addition to the properties of the microwave-induced resistance oscillations (MIRO) in photoresistance explained by theories for non-interacting 2D electrons, our theory predicts an irregular shape of MIRO at certain sample sizes, a peak in photoresistance near the doubled electron cyclotron frequency, and no dependence of MIRO on the helicity of the circular polarization of radiation. These effects, which are the evidences of the excitation of the transverse magnetosonic waves, were observed in magnetotransport experiments on ultra-high-quality GaAs quantum wells. We conclude that 2D electrons in such structures in magnetic field form a highly viscous fluid.Comment: 26 pages, 10 figure

Methods of conflict management at the aviation industry enterprises

The article deals with the management of hidden conflicts at the enterprises of the aviation industry. At present, a topical issue for the management of companies is the resource effectiveness of personnel, obtained as a result of the development or implementation of a management decision. The author emphasizes the importance of the conflict management process as a key tool for personnel management, on which the success of the company and sometimes the very existence of the enterprise, largely depends. The purpose of this work is to describe the conflict management methodology at the enterprises of the aviation industry by developing a model for identifying conflicts at an early stage. The main aspects of identifying conflict situations on the basis of modern theory and practice of conflict management are revealed. In this regard, the necessity for the top management of enterprises to make competent, economically sound management decisions is substantiated. A model for identifying hidden conflicts between employees is proposed

Evaluation of the Clinical Efficacy of Prednisolone in the Treatment of Inflammatory Bowel Diseases with Different Dosage Methods

Aim: to investigate the clinical efficacy of two methods of oral dosing of prednisolone (in mg and mg/kg) for the induction of remission for patients with ulcerative colitis (UC) and Crohn's disease (CD) using the technology of constructing and evaluating the effectiveness function (dose-effect relationship).Material and methods. In this study were included 86 patients aged from 18 to 65 years with moderate or severe active inflammatory bowel disease (61 — UC, 25 — CD). All patients were treated with prednisolone at an initial daily dose from 30 to 60 mg with a subsequent tapering of dose. The clinical response to treatment was evaluated at the time of complete withdrawal of prednisolone using the generally accepted criteria. Two efficiency functions were constructed, compared and analyzed: the first — at the initial dosage of prednisolone in mg and the second calculating the dose in mg/kg of patient weight. The patients' body weight ranged from 41 to 98 kg. The “dose-effect” relationship for prednisolone was constructed with statistical transformation of the baseline clinical data and a quantitative expression of the actual doses and alternative responses into a graph of the effectiveness function. The mean value at each point was estimated based on the regression kernel scoring method.Results. Two graphs of the “dose-effect” of prednisolone in mg and mg/kg of patient weight were constructed. The optimal clinically effective dose (OCED) when calculated in mg/kg of weight was 0.70 ± 0.01 (0.68 + 0.72) mg/kg with the corresponding effect 79.25 ± 6.26 (66.62 91.88) %. When two graphs in mg and mg / kg of weight were superimposed, it is shown that when an initial dose of 40 mg is prescribed without taking into account the patient's weight, the effect of therapy will be 25 % lower. Prescribing a dose of 60 mg per day without weight will be optimal for patients with a body weight of 85-90 kg. With a lower body weight, the clinical effect will not decrease, but the likelihood of recognized side effects of prednisolone should be expected in proportion to the decrease in body weight.Conclusion. The clinical efficacy of two methods of prednisolone dosing (mg and mg/kg) for patients with IBD during the first induction course was compared.Using a new technology for constructing and evaluating the effectiveness function (dose-effect relationship) allowed us to prove a reliable relationship between the body weight of patients with the clinical effect of prednisolone in patients with UC and CD. Based on the analysis of the dose-effect relationship, the optimal clinically effective dose of prednisolone for patients with UC and CD during the first induction course was established, equal to 0.70 mg/kg, which can be recommended for use in clinical practice for calculating individual doses

Exclusive pp→nnπ+π+pp \to nn \pi^{+}\pi^{+} reaction at LHC and RHIC

We evaluate differential distributions for the four-body $p p \to n n \pi^+ \pi^+$ reaction. The amplitude for the process is calculated in the Regge approach including many diagrams. We make predictions for possible future experiments at RHIC and LHC energies. Very large cross sections are found which is partially due to interference of a few mechanisms. Presence of several interfering mechanisms precludes extraction of the elastic $\pi^+ \pi^+$ scattering cross section. Absorption effects are estimated. Differential distributions in pseudorapidity, rapidity, invariant two-pion mass, transverse-momentum and energy distributions of neutrons are presented for proton-proton collisions at $\sqrt{s}$ = 500 GeV (RHIC) and $\sqrt{s}$ = 0.9, 2.36 and 7 TeV (LHC). Cross sections with experimental cuts are presented.Comment: 22 pages, 18 figures, calculations have been corrected, new processes added, discussion expanded in print in Phys. Rev.

Effect of Yb3+ doping level on the structure and spectroscopic properties of ZnO optical ceramics

This work was partly supported by the RFBR (Grant 19-03-00855).Zinc oxide optical ceramics with hexagonal structure doped with 0.6 –5.0 wt% Yb were fabricated by uniaxial hot pressing of commercial oxide powders at 1180 °C in vacuum. The ceramics were characterized by X-ray diffraction, SEM, EDX, X-ray and optical spectroscopy. It is shown that Yb3+ ions are distributed between C-type Yb2O3 sesquioxide crystals and ZnO grain boundaries. The Yb3+ doping of ZnO ceramics enhances the near-band-edge emission of zinc oxide. ZnO:Yb optical ceramics are promising for optoelectronic applications. © 2021 Institute of Physics Publishing. All rights reserved.RFBR (Grant 19-03-00855); The Institute of Solid State Physics, University of Latvia (Latvia), as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-Teaming Phase2 under grant agreement No. 739508, project CAMART2

DEVELOPMENT OF A CENTRALIZED AUTOMATED CONTROL AND DATA COLLECTION SYSTEM FROM ELECTRONIC COUNTER

As part of the project "Smart Home" was developed the system Impulse. This system is a fundamental element for automated control and data collection from standard electricity meters. The introduction of this system will solve the problems of energy saving and control system and data collection. Solving these problems will greatly facilitate the exchange of data between electricity suppliers (energy companies) and consumers. For this system was developed a unique software and hardware complex which includes functional management and monitoring modules.В рамках проекта «Умный дом» разработана система «Импульс». Данная система является основополагающим элементом для автоматизированного управления и сбора данных со стандартных электросчетчиков. Внедрение данной системы позволит решить проблемы, связанные с энергосбережением и системой управления и сбора данных. Решение этих проблем значительно облегчит обмен данными между поставщиками электроэнергии (энергетическими предприятиями) и потребителями. Для данной системы был разработан уникальный программно-аппаратный комплекс, который включает в себя функциональные модули управления и мониторинга

The game as a method of increasing the educational motivation of the future teacher of foreign languages

В статье рассматривается проблема мотивации в учебной деятельности. Мотивационная направленность будущих преподавателей иностранного языка обусловливает скорость и эффективность обучения. Повышению учебной мотивации способствуют различные виды игр: развивающие, обучающие, коммерческие, языковые, ролевые и социальные игры. Особое внимание в статье уделяется обучающим играм, которые в том числе повышают важный компонент мотивации – самоэффетивность обучаемых.The article deals with the problem of motivation in educational activities. The motivational orientation of future foreign language teachers determines the learning rate and its effectiveness. Various types of games contribute to the increase of educational motivation: educational, commercial, linguistic, role-playing and social games. Special attention in the article is paid to educational games, which also increase an important component of motivation – the self-effectiveness of students

The Role of Vesicles in Transporting of Cholera Toxin

The review reports on the secretion pathways of the main virulence factor of Vibrio cholerae, cholera toxin, both through the two-stage Sec-dependent type 2 secretion system and with the help of vesicles of the outer membrane of V. cholerae. The ways of toxin transfer into the host organism, depending on its form, are discussed. The well-studied free soluble cholera toxin is secreted extracellularly and transmitted in a GM1-dependent manner through cholesterolrich lipid rafts. The transfer of cholera toxin associated with vesicles has advantages over free toxin, because substances inside the outer membrane vesicles are protected from external proteases and host antibodies by the membrane that forms the vesicle. Vesicular transporting of cholera toxin into the target cell occurs via clathrin-dependent, caveolin-dependent and lipid raft-dependent endocytosis. The specific transport route is determined by the structure of the vesicles. Clathrindependent endocytosis is described for V. cholerae strains cultivated at low osmolarity of the medium, whose outer membrane vesicles contain the cholera toxin subunit A inside. Lipid raft-dependent endocytosis is characteristic of vesicles in which cholera toxin is located on the surface. In addition, endocytosis of V. cholerae outer membrane vesicles through structures known as caveolae is presented