Colossal variations in the thermopower and n-p conductivity switching in topological tellurides under pressure

Under applied high pressure, the electronic, optical, structural, and other properties of narrow-bandgap telluride semiconductors are subjected to dramatic changes. They can include, for instance, structural and electronic topological transitions. In this work, we investigated the electronic properties of single crystals of three families of tellurides, namely, HgTe, PbTe, and Bi2Te3 by measurements of the thermoelectric power (the Seebeck coefficient) and electrical resistance under high pressure up to 10 GPa. The applied pressure led to spectacular variations in the electronic transport of all three tellurides. We addressed these effects to electronic topological transitions that could be driven by significant narrowing of the bandgaps in the normal-pressure phases of these compounds. In particular, at about 1 GPa, we observed an n-p switching in the conductivity of HgTe, which was well reproducible under multiple pressure cycling. In contrast, in PbTe, we found that an electronic topological transition irreversibly turns the conductivity from p- to n-type. An electronic topological Lifshitz transition in p-type Bi2Te3 crystals with a low carrier concentration enhanced the n-type conductivity in a narrow pressure region about 2-3 GPa and resulted in a double p-n-p conductivity inversion. An irreversible p-n conductivity switching in p-type Bi2Te3 happened already on decompression from a high-pressure phase from about 8 GPa. The stress-controlled p-n inversions of the electrical conductivity in these industrially important telluride materials can potentially find emergent applications in micro- and nanoelectronics. © 2020 Author(s).The research was supported by a grant of Ministry of Science and Higher Education of the Russian Federation No. 075-15-2020-797 (13.1902.21.0024)

Mineral-petrochemical wallrock alteration of rocks in Bericul gold-ore deposit (Kuznetsk Alatau)

The distribution of mineral associations in near-veined zonal propylite-beresite metasomatic columns of mesothermal Bericul gold-ore deposit was analyzed. However, the polymineral composition in the inner (axial and adjacent with it rear) zones is inconsistent to the existing metasomatic column theoretical model. According to Korzhinskii metasomatic zoning theory, implied monomineral (quartz) and binary-mineral (quartz, sericite) compositions are characteristic of axial and rear zones, respectively. In common with above-mentioned facts, the zoning formation of differential component mobility is influenced by two additional factors: counter diffusion of components from fractured fluids into pores and diffusion mechanism of mass transfer it's from pores fluids into fractured of rock-fluid systems

Статеві особливості фізичного розвитку студентів

Sexual features of physical development of students studied at the technical specialties of higher educational establishments were studied. According to our data, there is not the authentic distinctions on calendar age between young men and girls. However, they differ by physical development and functional age. The rate of physical development of the girls is more than of the young men. The girls’ physical development is characterized by formation of internal system interrelations between elements of the functional system.Вивчалися статеві особливості фізичного розвитку у студентів технічних спеціальностей вищих навчальних закладів. Згідно з наведеними даними, між юнаками та дівчатами немає достовірної різниці за календарним віком. Однак, як за темпом фізичного розвитку, так і за показниками функціонального віку спостерігається достовірна різниця. У студенток фізико-технічного факультету спостерігається більший темп фізичного розвитку, ніж у студентів того ж факультету. Фізичний розвиток у дівчат характеризується формуванням внутрішньосистемних взаємозв’язків між елементами функціональної системи.Вивчалися статеві особливості фізичного розвитку у студентів технічних спеціальностей вищих навчальних закладів. Згідно з наведеними даними, між юнаками та дівчатами немає достовірної різниці за календарним віком. Однак, як за темпом фізичного розвитку, так і за показниками функціонального віку спостерігається достовірна різниця. У студенток фізико-технічного факультету спостерігається більший темп фізичного розвитку, ніж у студентів того ж факультету. Фізичний розвиток у дівчат характеризується формуванням внутрішньосистемних взаємозв’язків між елементами функціональної системи

Неотложная рентгенэндоваскулярная тромбаспирация при ишемическом кардиоэмболическом инсульте

A case report of successful intravascular aspiration in a patient with acute cardioembolic stroke is presented. Non-occlusive critical thrombosis of the extracranial segment of the left internal carotid artery with distal total embolization of the medial cerebral artery was verified. During the intervention, the dislocation of thrombotic masses into the supraclinoid segment occurred.Представлено клиническое наблюдение успешной внутрисосудистой аспирации у пациента с острым ишемическим инсультом кардиоэмболического генеза. Верифицирован неокклюзивный критический тромбоз экстракраниального сегмента левой внутренней сонной артерии с дистальной тотальной эмболизацией средней мозговой артерии. В ходе проведения вмешательства произошла дислокация тромботических масс в супраклиноидный сегмент

Анализ причин и структуры острой химической травмы по данным центра лечения острых отравлений города Омска за 2000—2004 годы

The purpose of the present study was to examine the pattern of acute intoxications and to analyze the causes of acute chemical injury in Omsk in the past 5 years. The patients referred for and admitted to the Acute Intoxication Center for acute chemical intoxication were qualitatively and quantitatively analyzed. The study has established that there was an increase in the number of patients referred for and admitted to the Acute Intoxication Center in the period of 2000 to 2004; the main causes of acute chemical injury being unintentional intoxications associated with alcoholization and ingestion of poisonous substances for suicidal purpose and a rise in the incidence of poisonings with narcotics. The study shows it expedient to elaborate a regional programme for the prevention of acute exogenous intoxications in the context of the region’s chemical safety jointly with drug addiction and psychiatric services.Цель настоящего исследования — изучение структуры острых отравлений и анализ причин возникновения острой химической травмы в г. Омске за последние 5 лет. Проведен качественный и количественный анализ обратившихся и госпитализированных больных с острым отравлением химической этиологии в Центр лечения острых отравлений. В результате проведенного исследования установлено, что за период с 2000 по 2004 гг. увеличилось количество обратившихся и госпитализированных больных в Центр лечения острых отравлений, основными причинами острой химической травмы стали непреднамеренные отравления с целью алкоголизации и приема ядовитых веществ с суицидальной целью, возросло количество отравлений наркотическими веществами. По результатам исследования целесообразным является создание совместно с наркологической и психиатрической службами региональной программы по профилактике острых экзогенных отравлений в контексте химической безопасности региона

Modelling Stochastic and Deterministic Behaviours in Virus Infection Dynamics

Many human infections with viruses such as human immunodeficiency virus type 1 (HIV--1) are characterized by low numbers of founder viruses for which the random effects and discrete nature of populations have a strong effect on the dynamics, e.g., extinction versus spread. It remains to be established whether HIV transmission is a stochastic process on the whole. In this study, we consider the simplest (so-called, 'consensus') virus dynamics model and develop a computational methodology for building an equivalent stochastic model based on Markov Chain accounting for random interactions between the components. The model is used to study the evolution of the probability densities for the virus and target cell populations. It predicts the probability of infection spread as a function of the number of the transmitted viruses. A hybrid algorithm is suggested to compute efficiently the dynamics in state space domain characterized by a mix of small and large species densities

First Principles Modeling of Nonlinear Incidence Rates in Seasonal Epidemics

In this paper we used a general stochastic processes framework to derive from first principles the incidence rate function that characterizes epidemic models. We investigate a particular case, the Liu-Hethcote-van den Driessche's (LHD) incidence rate function, which results from modeling the number of successful transmission encounters as a pure birth process. This derivation also takes into account heterogeneity in the population with regard to the per individual transmission probability. We adjusted a deterministic SIRS model with both the classical and the LHD incidence rate functions to time series of the number of children infected with syncytial respiratory virus in Banjul, Gambia and Turku, Finland. We also adjusted a deterministic SEIR model with both incidence rate functions to the famous measles data sets from the UK cities of London and Birmingham. Two lines of evidence supported our conclusion that the model with the LHD incidence rate may very well be a better description of the seasonal epidemic processes studied here. First, our model was repeatedly selected as best according to two different information criteria and two different likelihood formulations. The second line of evidence is qualitative in nature: contrary to what the SIRS model with classical incidence rate predicts, the solution of the deterministic SIRS model with LHD incidence rate will reach either the disease free equilibrium or the endemic equilibrium depending on the initial conditions. These findings along with computer intensive simulations of the models' Poincaré map with environmental stochasticity contributed to attain a clear separation of the roles of the environmental forcing and the mechanics of the disease transmission in shaping seasonal epidemics dynamics

Development of Professional Competences of teachers and Psychologists in the Conditions of Joint training

The article presents the results of an experiment to create a model of joint training of students studying on the programs 44.03.01 “Teacher education” and 44.03.03 “Special (defectological) education” at the university. The goal of such educational integration was to ensure the effective interaction of future professionals in these areas in the process of psychological and pedagogical support of schoolchildren with developmental delay who are studying in the conditions of inclusive or integrated environment. Traditional (separate) training of primary education teachers and special psychologists does not allow them to implement properly their professional competencies which are formed within autonomous educational approaches impeding productive cooperation in the context of modern educational practice.The experimental model of joint training of teachers of primary education and special psychologists has been being piloted at Murmansk Arctic State University for several years. The subject field is monitoring of individual development of primary school-age children with developmental delay. The quality of joint training was evaluated in the third and fourth grade curriculum. We assessed the development of cognitive and practical components of professional competences. On the whole the experiment involved 35 future teachers and 35 future special psychologists, 15 professors and 30 workers of educational institutions. The sampling consisted of the full-time students of 2010-2011 enrollment who were selected in two groups – control and experimental. The dynamics of the formation of professional competences was assessed according to the same parameters and we used a large number of diagnostic tests for interim and final evaluation. On the whole the experiment has been organized as a longitude study. During the experiment we have got 280 products of students’ work, which became the base to provide the rationale for the conclusion that joint training of future teachers of primary education and special psychologists has obvious advantages in comparison with the traditional model of students’ training. The professional competences demonstrated by the students of the experimental group were sufficient for providing an adequate psychological and pedagogical support of schoolchildren with developmental delay studying in the conditions of inclusive or integrated environment