767 research outputs found

    Improving legal drafting work of the state service of Ukraine for ethnic affairs and freedom of conscience

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    The State Service of Ukraine for Ethnic Affairs and Freedom of Conscience was established relatively recently. It is a public authority that is still in the process of establishing its activities, active research. This is the first starting point of the report. The second starting point of the report is that in the context of the coronavirus pandemic, many problems arise in the field of public health, the health of everyone. And these problems are often not only physical but also psychological. In such conditions, a person, in case of impossibility to receive qualified medical care, seeks to improve his psychological state on his own, including through active participation in the functioning of religious organizations.Державна служба України у справах національних національностей та свободи совісті була створений порівняно недавно. Це державний орган, який ще знаходиться в процесі становлення свою діяльність, активну дослідницьку діяльність. Це перша відправна точка звіту. Друга відправна точка доповіді – це в контексті коронавірусу пандемії виникає багато проблем у сфері громадського здоров’я, здоров’я кожного. І ці проблеми часто не тільки фізичні, а й психологічні. В таких умовах людина, в у разі неможливості отримати кваліфіковану медичну допомогу, прагне покращити свій психологічний стан держави самостійно, в тому числі шляхом активної участі у функціонуванні культ організацій

    Highly mobile carriers in orthorhombic phases of iron-based superconductors FeSe1x{}_{1-x}Sx{}_{x}

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    The field and temperature dependencies of the longitudinal and Hall resistivity have been measured for FeSe1x{}_{1-x}Sx{}_{x} (x=0.04, 0.09 and 0.19) single crystals. The sample FeSe0.81{}_{0.81}S0.19{}_{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 FeSe0.81{}_{0.81}S0.19{}_{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

    Radiography of the Earth's Core and Mantle with Atmospheric Neutrinos

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    A measurement of the absorption of neutrinos with energies in excess of 10 TeV when traversing the Earth is capable of revealing its density distribution. Unfortunately, the existence of beams with sufficient luminosity for the task has been ruled out by the AMANDA South Pole neutrino telescope. In this letter we point out that, with the advent of second-generation kilometer-scale neutrino detectors, the idea of studying the internal structure of the Earth may be revived using atmospheric neutrinos instead.Comment: 4 pages, LaTeX file using RevTEX4, 2 figures and 1 table included. Matches published versio

    Magnetotransport properties of FeSe in fields up to 50T

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    Magnetotransport properties of the high-quality FeSe crystal, measured in a wide temperature range and in magnetic fields up to 50 T, show the symmetry of the main holelike and electronlike bands in this compound. In addition to the main two bands, there is also a tiny, highly mobile, electronlike band which is responsible for the non-linear behavior of ρxy\rho_{xy}(B) at low temperatures and some other peculiarities of FeSe. We observe the inversion of the ρxx\rho_{xx} temperature coeficient at a magnetic field higher than about 20 T which is an implicit conformation of the electron-hole symmetry in the main bands.Comment: MISM 201

    Signatures of cosmic tau-neutrinos

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    The importance and signatures of cosmic tau--(anti)neutrinos have been studied for upward-- and downward--going μ+μ+\mu^-+\mu^+ and hadronic shower event rates relevant for present and future underground water or ice detectors, utilizing the unique and reliable ultrasmall--xx predictions of the dynamical (radiative) parton model. The upward--going μ+μ+\mu^- +\mu^+ event rates calculated just from cosmic νμ+νˉμ\nu_{\mu}+\bar{\nu}_{\mu} fluxes are sizeably enhanced by taking into account cosmic ντ+νˉτ\nu_{\tau}+ \bar{\nu}_{\tau} fluxes and their associated τ+τ+\tau^- +\tau^+ fluxes as well. The coupled transport equations for the upward--going ν()τ\stackrel{(-)}{\nu}_{\tau} flux traversing the Earth imply an enhancement of the attenuated and regenerated ν()τ\stackrel{(-)}{\nu}_{\tau} flux typically around 10410510^4-10^5 GeV with respect to the initial cosmic flux. This enhancement turns out to be smaller than obtained so far, in particular for flatter initial cosmic fluxes behaving like Eν1E_{\nu}^{-1}. Downward--going μ+μ+\mu^- +\mu^+ events and in particular the background--free and unique hadronic `double bang' and `lollipop' events allow to test downward--going cosmic ντ+νˉτ\nu_{\tau} +\bar{\nu}_{\tau} fluxes up to about 10910^9 GeV.Comment: 32 pages, 6 figures; Added reference

    Majority carrier type inversion in FeSe family and "doped semimetal" scheme in iron-based superconductors

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    The field and temperature dependencies of the longitudinal and Hall resistivity have been studied for high-quality FeSe1x{}_{1-x}Sx{}_{x} (x up to 0.14) single crystals. Quasiclassical analysis of the obtained data indicates a strong variation of the electron and hole concentrations under the studied isovalent substitution and proximity of FeSe to the point of the majority carrier-type inversion. On this basis, we propose a `doped semimetal' scheme for the superconducting phase diagram of the FeSe family, which can be applied to other iron-based superconductors. In this scheme, the two local maxima of the superconducting temperature can be associated with the Van Hove singularities of a simplified semi-metallic electronic structure. The multicarrier analysis of the experimental data also reveals the presence of a tiny and highly mobile electron band for all the samples studied. Sulfur substitution in the studied range leads to a decrease in the number of mobile electrons by more than ten times, from about 3\% to about 0.2\%. This behavior may indicate a successive change of the Fermi level position relative to singular points of the electronic structure which is consistent with the `doped semimetal' scheme. The scattering time for mobile carriers does not depend on impurities, which allows us to consider this group as a possible source of unusual acoustic properties of FeSe

    Prompt muon contribution to the flux underwater

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    We present high energy spectra and zenith-angle distributions of the atmospheric muons computed for the depths of the locations of the underwater neutrino telescopes. We compare the calculations with the data obtained in the Baikal and the AMANDA muon experiments. The prompt muon contribution to the muon flux underwater due to recent perturbative QCD-based models of the charm production is expected to be observable at depths of the large underwater neutrino telescopes. This appears to be probable even at rather shallow depths (1-2 km), provided that the energy threshold for muon detection is raised above 100\sim 100 TeV.Comment: 7 pages, RevTeX, 7 eps figures, final version to be published in Phys.Rev.D; a few changes made in the text and the figures, an approximation formula for muon spectra at the sea level, the muon zenith-angle distribution table data and references adde

    Prompt neutrino fluxes from atmospheric charm

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    We calculate the prompt neutrino flux from atmospheric charm production by cosmic rays, using the dipole picture in a perturbative QCD framework, which incorporates the parton saturation effects present at high energies. We compare our results with the next-to-leading order perturbative QCD result and find that saturation effects are large for neutrino energies above 10^6 GeV, leading to a substantial suppression of the prompt neutrino flux. We comment on the range of prompt neutrino fluxes due to theoretical uncertainties.Comment: 13 pages with 11 figures; expanded discussion, added references, version to be published in Phys. Rev.
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