338 research outputs found

    Quality standards for distance learning in higher education: a comparative analysis of Canadian and Russian practices

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    The aim of the investigation is to perform comparative analysis of the quality assessment and policies of quality assurance in postsecondary education in Canada and Russian Federation. Methods. The theoretical methods involve comparative analysis and synthesis, induction and deduction, extrapolation and modelling. Results. Russia and Canada have different policies on quality assurance in the distance learning and are at different stages of implementation of distance learning into postsecondary curricula. The Canadian system of postsecondary education is regulated not by the State but by professional societies, licensing organisations, and experts. Canadian postsecondary institutions have efficient systems of quality assurance, quality standards and accreditation. Blended learning is widely used in Canadian medical schools and is mandatory for continuous professional development. In Russia, the system of quality assurance for distance learning is regulated by the State. At present, Russia has developed policies on distance learning but unified quality standards in this field are absent. Blended learning is used in the medical schools but its implementation has just begun as continuous professional development. Scientific novelty. For the first time, the results of comparative analysis of the policies on quality assurance in distance learning in Russia and Canada are described. Practical significance. This research has showed the needs of the development of the system of quality standards and the policy on quality assurance of distance learning in the Russia postsecondary educationЦель статьи – сравнительный анализ стандартов качества дистанционного образования в высшей школе в Канаде и России. Методы исследования – теоретические: компаративный, анализ и синтез, индукция и дедукция, экстраполяция и моделирование. Результаты. Установлено, что в России и Канаде существуют разные модели оценки качества и экспертизы дистанционного образования, которые находятся на разных этапах внедрения в образовательный процесс дистанционного образования (ДО). В канадской высшей школе нормативное регулирование ДО осуществляется с участием негосударственных структур (независимых экспертов, профессионального сообщества); эффективно функционирует система стандартизации качества в этой области; есть система аккредитации электронных ресурсов; разработаны руководства для пользователей. На территории Канады широкое распространение получила смешанная форма обучения (hybrid method, blended method). Примером тому служит подготовка специалистов в области медицины, где дополнительное профессиональное образование стало невозможным без дистанционных технологий. В отличие от канадской, российская система оценки качества строго иерархизирована и полностью осуществляется государством. Отечественная высшая школа прошла этап создания нормативной базы ДО, определения понятий «цифровой педагогики», но критерии качества дистанционного образования в правовых документах отсутствуют. Общей чертой использования ДО в обеих странах является наличие смешанного обучения, однако в наших вузах дистанционные технологии постдипломного образования только начинают внедряться, а для канадских коллег они уже стали нормой, а зачастую и обязательной составляющей продолжения образования и повышения квалификации (как, например, в медицинской сфере). Научная новизна. Впервые представлены результаты компаративного анализа нормативной базы и практики оценивания результатов обучения в высшей школе с использованием дистанционных технологий в РФ и Канаде. Практическая значимость данного материала заключается в выявлении актуальных потребностей отечественной системы образования по стандартизации качества дистанционного обучения: в российской высшей школе назрела необходимость создания процедуры аттестации качества электронных образовательных ресурсов, и это касается всей системы непрерывного профессионального образовани

    New constraints for non-Newtonian gravity in nanometer range from the improved precision measurement of the Casimir force

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    We obtain constraints on non-Newtonian gravity following from the improved precision measurement of the Casimir force by means of atomic force microscope. The hypothetical force is calculated in experimental configuration (a sphere above a disk both covered by two metallic layers). The strengthenings of constraints up to 4 times comparing the previous experiment and up to 560 times comparing the Casimir force measurements between dielectrics are obtained in the interaction range 5.9 nmλ115\leq\lambda\leq 115 nm. Recent speculations about the presence of some unexplained attractive force in the considered experiment are shown to be unjustified.Comment: 5 pages, 1 figur

    Constraints for hypothetical interactions from a recent demonstration of the Casimir force and some possible improvements

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    The Casimir force is calculated in the configuration of a spherical lens and a disc of finite radius covered by CuCu and AuAu thin layers which was used in a recent experiment. The correction to the Casimir force due to finiteness of the disc radius is shown to be negligible. Also the corrections are discussed due to the finite conductivity, large-scale and short-scale deviations from the perfect shape of the bounding surfaces and the temperature correction. They were found to be essential when confronting the theoretical results with experimental data. Both Yukawa-type and power-law hypothetical forces are computed which may act in the configuration under consideration due to the exchange of light and/or massless elementary particles between the atoms of the lens and the disc. New constraints on the constants of these forces are determined which follow from the fact that they were not observed within the limits of experimental errors. For Yukawa-type forces the new constraints are up to 30 times stronger than the best ones known up today. A possible improvement of experimental parameters is proposed which gives the possibility to strengthen constraints on Yukawa-type interactions up to 10410^4 times and on power-law interactions up to several hundred times.Comment: 15 pages, 3 figures, subm. to Phys. Rev.

    Resistive state of superconducting structures with fractal clusters of a normal phase

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    The effect of morphologic factors on magnetic flux dynamics and critical currents in percolative superconducting structures is considered. The superconductor contains the fractal clusters of a normal phase, which act as pinning centers. The properties of these clusters are analyzed in the general case of gamma-distribution of their areas. The statistical characteristics of the normal phase clusters are studied, the critical current distribution is derived, and the dependencies of the main statistical parameters on the fractal dimension are found. The effect of fractal clusters of a normal phase on the electric field induced by the motion of the magnetic flux after the vortices have been broken away from pinning centers is considered. The voltage-current characteristics of fractal superconducting structures in a resistive state for an arbitrary fractal dimension are obtained. It is found that the fractality of the boundaries of normal phase clusters intensifies magnetic flux trapping and thereby increases the current-carrying capability of the superconductor.Comment: 15 pages with 8 figures, revtex3, alternative e-mail of author is [email protected]

    Magnetothermopower and Magnetoresistivity of RuSr2Gd1-xLaxCu2O8 (x=0, 0.1)

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    We report measurements of magnetothermopower and magnetoresistivity as a function of temperature on RuSr2Gd1-xLaxCu2O8 (x = 0, 0.1). The normal-state thermopower shows a dramatic decrease after applying a magnetic field of 5 T, whereas the resistivity shows only a small change after applying the same field. Our results suggest that RuO2 layers are conducting and the magnetic field induced decrease of the overall thermopower is caused by the decrease of partial thermopower decrease associated with the spin entropy decrease of the carriers in the RuO2 layers.Comment: 21 pages, 6 figure

    Towards the solution of the CP/CAC_{P}/C_{A} anomaly in shell-model calculations of muon capture

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    Recently many authors have performed shell-model calculations of nuclear matrix elements determining the rates of the ordinary muon capture in light nuclei. These calculations have employed well-tested effective interactions in large scale shell-model studies. For one of the nuclei of interest, namely 28^{28}Si, there exists recent experimental data which can be used to deduce the value of the ratio CP/CAC_{P}/C_{A} by using the calculated matrix elements. Surprisingly enough, all the abovementioned shell-model results suggest a very small value (0\simeq 0) for CP/CAC_{P}/C_{A}, quite far from the PCAC prediction and recent data on muon capture in hydrogen. We show that this rather disturbing anomaly is solved by employing effective transition operators. This finding is also very important in studies of the scalar coupling of the weak charged current of leptons and hadrons.Comment: Revtex, 6 pages, 2 figs include

    Charging Ultrasmall Tunnel Junctions in Electromagnetic Environment

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    We have investigated the quantum admittance of an ultrasmall tunnel junction with arbitrary tunneling strength under an electromagnetic environment. Using the functional integral approach a close analytical expression of the quantum admittance is derived for a general electromagnetic environment. We then consider a specific controllable environment where a resistance is connected in series with the tunneling junction, for which we derived the dc quantum conductance from the zero frequency limit of the imaginary part of the quantum admittance. For such electromagnetic environment the dc conductance has been investigated in recent experiments, and our numerical results agree quantitatively very well with the measurements. Our complete numerical results for the entire range of junction conductance and electromagnetic environmental conductance confirmed the few existing theoretical conclusions.Comment: 7 pages, 3 ps-figure

    Formation of "Lightnings" in a Neutron Star Magnetosphere and the Nature of RRATs

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    The connection between the radio emission from "lightnings" produced by the absorption of high-energy photons from the cosmic gamma-ray background in a neutron star magnetosphere and radio bursts from rotating radio transients (RRATs) is investigated. The lightning length reaches 1000 km; the lightning radius is 100 m and is comparable to the polar cap radius. If a closed magnetosphere is filled with a dense plasma, then lightnings are efficiently formed only in the region of open magnetic field lines. For the radio emission from a separate lightning to be observed, the polar cap of the neutron star must be directed toward the observer and, at the same time, the lightning must be formed. The maximum burst rate is related to the time of the plasma outflow from the polar cap region. The typical interval between two consecutive bursts is ~100 s. The width of a single radio burst can be determined both by the width of the emission cone formed by the lightning emitting regions at some height above the neutron star surface and by a finite lightning lifetime. The width of the phase distribution for radio bursts from RRATs, along with the integrated pulse width, is determined by the width of the bundle of open magnetic field lines at the formation height of the radio emission. The results obtained are consistent with the currently available data and are indicative of a close connection between RRATs, intermittent pulsars, and extreme nullers.Comment: 24 pages, no figures, references update

    Measurement of the Pion Form Factor in the Energy Range 1.04-1.38 GeV with the CMD-2 Detector

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    The cross section for the process e+eπ+πe^+e^-\to\pi^+\pi^- is measured in the c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events including 860000 e+ee^+e^- events, 82000 μ+μ\mu^+\mu^- events, and 33000 π+π\pi^+\pi^- events. The systematic and statistical errors of measuring the pion form factor are equal to 1.2-4.2 and 5-13%, respectively.Comment: 5 pages, 2 figure

    Disorder Induced Ferromagnetism in Restricted Geometries

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    We study the influence of on-site disorder on the magnetic properties of the ground state of the infinite UU Hubbard model. We find that for one dimensional systems disorder has no influence, while for two dimensional systems disorder enhances the spin polarization of the system. The tendency of disorder to enhance magnetism in the ground state may be relevant to recent experimental observations of spin polarized ground states in quantum dots and small metallic grains.Comment: 4 pages, 4 figure
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