Interaction of 3D mesostructures composed of Pd-Ni alloy nanowires with low-temperature oxygen plasma

© 2017We report that volumetric mesoporous structures obtained via self-organization of Pd-Ni nanowires interact actively with low temperature non-equilibrium oxygen plasma. This interaction leads to strong red incandescence of the composite nanostrucutures. After the plasma-chemical treatment, the X-ray diffraction pattern reveals presence of nanocrystalline nickel (II) oxide phase on surface of the samples. Measurements of electromagnetic response indicate that the samples exposed to oxygen plasma retain metallic type conductivity which is similar to the pristine Pd-Ni samples. Thus our studies indicate that the plasma-chemical treatment yields novel composite 3D hierarchical structures with a highly conductive skeleton of Pd-Ni nanowires covered by a thin nickel (II) oxide semiconducting layer of large surface area. These structures are attractive for applications

Коммуникационные практики сохранения контингента студентов в системе дистанционного образования

Modern educational programs of distance education are gaining popularity and demand among applicants with different educational needs. Such programs are aimed at overcoming educational inequality and equalization of educational opportunities, solving problems of inclusive education, incorporation in the system of continuous education. The study objective is to identify the role of educational communications and their effect on preserving the student contingent in distance education. The paper focuses on identifying the reasons to discontinue by students their studies in vocational educational programs conducted using distance learning technologies; determining the communication aspects of the problem to maintain a contingent of students in the professional educational programs of Bachelor and Master.The authors determine the motives for choosing the program, involvement in educational communications, satisfaction with the educational process and its components, as well as difficulties in mastering the program based on the student opinions in «the group at risk of expulsion» and studied in such educational programs, but for various reasons do not complete the studies. The research has solved the following tasks: considering educational communication practices in the system of distance learning; identifying the reasons of difficulties and expulsions of students in obtaining higher professional education by the programs of distance education; forming proposals on the organization of educational communications aimed more successful mastering of the educational program and preservation of the student contingent in the distance learning system. The study results should be used to organize communication and methodological support of professional educational programs of distance education.Современные образовательные программы, осуществляемые с применением дистанционных технологий, приобретают популярность и востребованность у абитуриентов с разными образовательными потребностями. Такие программы ориентированы на преодоление образовательного неравенства и выравнивание образовательных возможностей, решение задач инклюзивного образования, включение в систему непрерывного образования. Целью исследования является определение роли образовательных коммуникаций и их влияния на сохранение контингента студентов в системе дистанционного образования. Фокус исследования направлен на выявление причин, по которым студенты прекращают обучение по профессиональным образовательным программам, осуществляемым с применением дистанционных образовательных технологий, и определение коммуникационных аспектов проблемы сохранения контингента обучающихся на профессиональных образовательных программах бакалавриата и магистратуры.На основе мнений студентов «группы риска отчисления» и студентов, обучавшихся на таких образовательных программах, но по разным причинам не завершивших обучение, определяются мотивы выбора программы, вовлеченность в учебные коммуникации, удовлетворенность образовательным процессом и его составляющими, а также трудности в освоении программы. В ходе исследования были решены следующие задачи: рассмотрены образовательные коммуникационные практики в системе дистанционного обучения; выявлены причины затруднений и отчислений студентов при получении высшего профессионального образования по программам, осуществляемым с применением дистанционных образовательных технологий; сформированы предложения по организации образовательных коммуникаций, направленных на более успешное освоение образовательной программы и сохранение контингента обучающихся в системе дистанционного образования. Результаты исследования могут быть использованы для организации коммуникационного и методического сопровождения профессиональных образовательных программ, осуществляемых с применением дистанционных технологий

Structure and magnetic properties of nanostructured Pd-Fe thin films produced by pulse electrodeposition

Nanostructured Pd-Fe thin films with varied Fe content were prepared by electrodeposition technique from organic electrolytes on Cu and brass substrates. The structure and the magnetic properties of the films were investigated prior to post-deposition annealing. The structure of the Pd 1-xFe x thin film with x = 0.14, 0.24, and 0.52 was determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM) as a solid solution of iron in palladium face-centered cubic lattice with the (111) orientation of nanograins relatively to the substrate surface. The films with higher iron concentration, x = 0.74, 0.91, have structure of a solid solution based on the body-centered cubic lattice. The average grain size determined by the scanning electron microscopy (SEM) for the first two alloys is 7-10 nm, and for the latter ones it is about 120 nm. The saturation magnetization of the films has linear dependence on the iron content, but coercivity has non-monotonic dependence on x, i.e., the films with x = 0.68 show highest coercivity. The magnetic anisotropy of the samples is studied by ferromagnetic resonance (FMR) spectroscopy. Copyright © 2011 American Scientific Publishers. All rights reserved

‘Good fences make good neighbours’: Concepts and records of range dynamics in ground squirrels and geographical barriers in the Pleistocene of the Circum-Black Sea area

Ground squirrels were an important member of the Pleistocene steppe-tundra mammal community. They evolved ecological specialisations and exhibit behaviours that make them particularly informative subjects to study palaeoenvironmental constraints affecting species distribution and speciation. Interspecific competition and isolating geographical barriers are considered as the principal factors that define species range boundaries. The present paper provides a first comprehensive compilation of the living and extinct Spermophilus species in Europe. These data suggest ‘patchwork quilt’ model for the expansion and spatial distribution of ground squirrel species. Here we consider mainly small-sized Spermophilus species because large-sized (e.g., S. superciliosus) ground squirrels consist another ‘patchwork quilt’, which overlap the first one. This overlapping of the species ranges is possible because of the size difference that lowers interspecific competition (Hutchinson's rule). We consider two main types of range boundaries. One type includes roughly ‘sub-parallel’ boundaries that oscillate in concert with climatic and vegetational changes (a case of climatically controlled competitive exclusion). The other type consists of roughly ‘sub-meridional’ boundaries corresponding to geographical barriers (e.g., water barriers, mountain ridges); these boundaries are rather stable. Examples of ‘sub-parallel range modifications include: oscillations of boundaries between S. pygmaeus and S. suslicus; the immigration of S. citellus into the Pre-Carpathian area; the branching of S. suslicus from S. pygmaeus; the regional appearance of the Late Pleistocene species S. severskensis and S. citelloides. Examples of ‘sub-meridional events’ are: the crossing of the Danube by S. citellus; the appearance of an isolated population of S. pygmaeus on right bank of the Dnieper during the Late Pleistocene to Middle Holocene; a crossing of the Dnieper river by S. pygmaeus, which resulted in the appearance of S. odessanus; the intrusion of eastern populations of S. pygmaeus into the Trans-Volga areas. © 2018 Elsevier Ltd and INQU

Ancient DNA of narrow-headed vole reveal common features of the Late Pleistocene population dynamics in cold-adapted small mammals

The narrow-headed vole, collared lemming and common vole were the most abundant small mammal species across the Eurasian Late Pleistocene steppe-tundra environment. Previous ancient DNA studies of the collared lemming and common vole have revealed dynamic population histories shaped by climatic fluctuations. To investigate the extent to which species with similar adaptations share common evolutionary histories, we generated a dataset comprised the mitochondrial genomes of 139 ancient and 6 modern narrow-headed voles from several sites across Europe and northwestern Asia covering approximately the last 100 thousand years (kyr). We inferred Bayesian time-aware phylogenies using 11 radiocarbon-dated samples to calibrate the molecular clock. Divergence of the main mtDNA lineages across the three species occurred during marine isotope stages (MIS) 7 and MIS 5, suggesting a common response of species adapted to open habitat during interglacials. We identified several time-structured mtDNA lineages in European narrow-headed vole, suggesting lineage turnover. The timing of some of these turnovers was synchronous across the three species, allowing us to identify the main drivers of the Late Pleistocene dynamics of steppe- and cold-adapted species.NWOVI.C.191.070Human Origin