Hybridization and spin-orbit coupling effects in quasi-one-dimensional spin-1/2 magnet Ba3Cu3Sc4O12

We study electronic and magnetic properties of the quasi-one-dimensional spin-1/2 magnet Ba3Cu3Sc4O12 with a distinct orthogonal connectivity of CuO4 plaquettes. An effective low-energy model taking into account spin-orbit coupling was constructed by means of first-principles calculations. On this basis a complete microscopic magnetic model of Ba3Cu3Sc4O12, including symmetric and antisymmetric anisotropic exchange interactions, is derived. The anisotropic exchanges are obtained from a distinct first-principles numerical scheme combining, on one hand, the local density approximation taking into account spin-orbit coupling, and, on the other hand, projection procedure along with the microscopic theory by Toru Moriya. The resulting tensors of the symmetric anisotropy favor collinear magnetic order along the structural chains with the leading ferromagnetic coupling J1 = -9.88 meV. The interchain interactions J8 = 0.21 meV and J5 = 0.093 meV are antiferromagnetic. Quantum Monte Carlo simulations demonstrated that the proposed model reproduces the experimental Neel temperature, magnetization and magnetic susceptibility data. The modeling of neutron diffraction data reveals an important role of the covalent Cu-O bonding in Ba3Cu3Sc4O12.Comment: 11 pages, 12 figure

Magnetically frustrated synthetic end member Mn2(PO4)OH in the triplite-triploidite family

The manganese end member of triplite-triploidite series of compounds, Mn2(PO4)OH, is synthesized by a hydrothermal method. Its crystal structure is refined in the space group P21/c with a = 12.411(1) Å, b = 13.323(1) Å, c = 10.014(1) Å, β = 108.16(1), V = 1573.3 Å3, Z = 8, and R = 0.0375. Evidenced in measurements of magnetization M and specific heat Cp, Mn2(PO4)OH reaches a long range antiferromagnetic order at TN = 4.6 K. As opposed to both triplite Mn2(PO4)F and triploidite-type Co2(PO4)F, the title compound is magnetically frustrated being characterized by the ratio of Curie-Weiss temperature Θ to Néel temperature TN of about 20. The large value of frustration strength Θ/TN stems from the twisted saw tooth chain geometry of corner sharing triangles of Mn polyhedra, which may be isolated within tubular fragments of a triploidite crystal structure. © 2017 The Royal Society of Chemistry.We thank E. V. Guseva for the X-ray spectral analysis of the sample and N. V. Zubkova for her help in the X-ray experiment. This work was supported by the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST "MISiS" project K2-2016-066 and by RFBR projects 15-05-06742, 16-02-00021 and 17-02-00211. The work was supported by Act 211 Government of the Russian Federation, contracts 02.A03.21.0004, 02.A03.21.0006 and 02.A03.21.0011

Highly mobile carriers in orthorhombic phases of iron-based superconductors FeSe1−x{}_{1-x}Sx{}_{x}

The field and temperature dependencies of the longitudinal and Hall resistivity have been measured for FeSe${}_{1-x}$S${}_{x}$ (x=0.04, 0.09 and 0.19) single crystals. The sample FeSe${}_{0.81}$S${}_{0.19}$ does not show a transition to an orthorhombic phase and exhibits at low temperatures the transport properties quite different from those of orthorhombic samples. The behavior of FeSe${}_{0.81}$S${}_{0.19}$ is well described by the simple two band model with comparable values of hole and electron mobility. In particular, at low temperatures the transverse resistance shows a linear field dependence, the magnetoresistance follow a quadratic field dependence and obeys to Kohler's rule. In contrast, Kohler's rule is strongly violated for samples having an orthorhombic low temperature structure. However, the transport properties of the orthorhombic samples can be satisfactory described by the three band model with the pair of almost equivalent to the tetragonal sample hole and electron bands, supplemented with the highly mobile electron band which has two order smaller carrier number. Therefore, the peculiarity of the low temperature transport properties of the orthorhombic Fe(SeS) samples, as probably of many other orthorhombic iron superconductors, is due to the presence of a small number of highly mobile carriers which originate from the local regions of the Fermi surface, presumably, nearby the Van Hove singularity points

ЗМІСТ ТА ТЕХНОЛОГІЇ ПІДГОТОВКИ МАЙБУТНІХ УЧИТЕЛІВ ДО ЗДІЙСНЕННЯ НЕВЕРБАЛЬНОЇ КОМУНІКАЦІЇ

The semantic and technological components of preparation of future teachers for the realization of unverbal communication are grounded.Обоснованы смысловой и технологический компоненты подготовки будущих учите­лей к осуществлению невербальной коммуникации.Обґрунтовано змістовий та технологічний компоненти підготовки майбутніх учителів до здійснення невербальної комунікації

The Frontiers of Academic Discipline: Institutional Approach (the Case of Accounting)

The issues of institutionalization and demarcation of the boundaries of academic disciplines in recent years have received a significant interest, within the framework of new waves of epistemological and institutional research and interdisciplinarity. The aim of this work is to model the process of academic discipline’s institutionalization and the structure of its institutions by the case of accounting discipline, in the international and Russian context. Due to the specific nature of the subject, we will use the institutional approach as well as the associated socialnetwork approach within which discipline is viewed as the result of the interaction of individual actors, their groups and networks in the subject discourse. The paper identifies the reasons for interest in demarcating the boundaries of academic disciplines in general, and accounting in particular. The institutional structure of accounting is defined as a set of institutions of accounting practices (techniques and professions) and accounting knowledge (science and the dissemination of knowledge (education and professional communication)). The stages of development of all these institutions are structured; special attention is paid to the institutions of accounting knowledge. It is shown that today accounting, institutionally, is a mature academic discipline, a separate part of economic science and practice. The main features of accountants’ academic community network organization are revealed: its tightness facilitates the exchange of knowledge within the community, but also hinders the search for new objects and methods of research and interdisciplinarity. The features of the development of accounting institutions in the Russian academic environment are discussed. The importance of the results is due to the possibilities of social construction in society and in markets that are provided by all economic disciplines, including accounting. The model of the structure of institutions and networks presented in this work can be extended to other disciplines that will help overcome the existing gap between the content of domestic and foreign ideas about their institutional nature and subject fields, as well as the revision of Russian national educational and research classifications, the content of training programs in economic disciplines, including accounting.Вопросы институциализации различных областей знания и демаркации границ академических дисциплин в последние годы получили заметный толчок к развитию в рамках новых волн эпистемологических и институциональных исследований и интереса к междисциплинарности. Целью данной работы является моделирование процесса институциализации академической дисциплины и структуры ее институтов на примере (бухгалтерского) учета, в международном и российском контексте. В силу особенностей тематики мы будем использовать институциональный подход, а также близкий к нему социально-сетевой, в рамках которого дисциплина рассматривается как результат взаимодействия отдельных акторов, их групп и сетей в предметном дискурсе. В работе выявлены причины интереса к демаркации границ академических дисциплин вообще, и учета в частности. Институциональная структура учета определена как совокупность институтов учетных практик (техник и профессий) и учетного знания (науки и распространения знания (образования и профессиональной коммуникации)). Структурированы этапы развития всех этих институтов; особое внимание уделено институтам учетного знания. Показано, что с институциональной точки зрения сегодня учет является зрелой академической дисциплиной, обособленный раздел экономической науки и практики. Выявлены основные черты сетевой организации академического сообщества «бухгалтеров»: его герметичность облегчает обмен знаниями внутри сообщества, но препятствует поиску новых объектов и методов исследований и междисциплинарности. Обсуждаются особенности развития институтов учета в российской академической среде. Важность результатов обусловлена возможностями социального конструирования в обществе и на рынках, которые дают все экономические дисциплины, в том числе учет. Представленная в работе модель структуры институтов и сетей может быть распространена на другие дисциплины, что будет способствовать преодолению имеющегося разрыва между содержанием отечественных и зарубежных представлений об их институциональной природе и предметных полях, а также пересмотру отечественных образовательных и научных классификаторов, содержания программ обучения экономическим дисциплинам, в том числе учету

Self-oscillations in rocks,results of laboratory experiments

The method of generation of self-oscillations in rocks is developed here. Self-oscillations arise as a result of direct and inverse mechanoelectric transformations without an external generator. Laboratory experiments were executed with different samples. A relation between self-oscillation parameters from samples humidity and direct electrical field applied to samples was detected

Gestational diabetes mellitus: current screening problems

Gestational diabetes mellitus (GDM) is characterized as hyperglycemia, first detected during pregnancy, yet not meeting the criteria for “manifest” diabetes mellitus. GDM is one of the most common gestational complications. This pathology is associated with many adverse pregnancy outcomes, both on the part of the mother and the fetus. The problem of identifying GDM has acquired particular relevance and significance for the healthcare system at the moment due to the steady increase in the prevalence of such risk factors of GDM as obesity and late pregnancy. The history of screening and diagnosis of GDM has undergone a number of significant changes in a short time. Currently, different clinical guidelines offer different approaches to GDM screening, thus, a unified approach to identifying this pathology has not yet been formulated and adopted. The purpose of this review was to discover the current clinical guidelines for the detection of GDM at 24–28 weeks of pregnancy, including historical context of their origin and development, to describe these approaches, as well as to critically evaluate them with a discussion of the main advantages and disadvantages of each of them