491 research outputs found

    A comparative analysis of the causes of intrapersonal conflicts of high school students and working youth

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    Исследуется сущность внутриличностных конфликтов, обобщаются результаты пилотажного исследования.Explores the nature of conflict, summarizes the realization of flight research

    Probing the role of Nd3+ ions in the weak multiferroic character of NdMn2O5 by optical spectroscopies

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    Raman and infrared spectroscopies are used as local probes to study the dynamics of the Nd-O bonds in the weakly multiferroic NdMn2O5 system. The temperature dependence of selected Raman excitations reveals the splitting of the Nd-O bonds in NdMn2O5. The Nd3+ ion crystal field (CF) excitations in NdMn2O5 single crystals are studied by infrared transmission as a function of temperature, in the 1800-8000 cm-1 range, and under an applied magnetic field up to 11 T. The frequencies of all 4Ij crystal-field levels of Nd3+ are determined. We find that the degeneracy of the ground-state Kramers doublet is lifted ({\Delta}0 ~7.5 cm-1) due to the Nd3+-Mn3+ interaction in the ferroelectric phase, below TC ~ 28 K. The Nd3+ magnetic moment mNd(T) and its contribution to the magnetic susceptibility and the specific heat are evaluated from {\Delta}0(T) indicating that the Nd3+ ions are involved in the magnetic and the ferroelectric ordering observed below ~ 28 K. The Zeeman splitting of the excited crystal field levels of the Nd3+ ions at low temperature is also analyzed.Comment: This paper is accepted for publication as a Regular Article in Physical Review

    X-ray Diffraction Study of Superstructure in GdBaCo2O5.5

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    A single crystal of GdBaCo2O5.47(2) has been studied by means of X-ray diffraction. Appearance of superstructure reflections at T = 341.5(7) K gives an evidence of continuous transition to the phase with unit cell doubled along the shortest edge a1. Critical exponent for the order parameter is found to be beta=0.33(1). The superstructure reflections are about 2-4 orders of magnitude weaker than the basic ones. Their systematic extinction indicates the crystal symmetry change from Pmmm to Pmma. The integrated intensities allow to calculate displacements of atoms from the positions in the high-temperature phase. The cobalt-ligand distances in the ordered phase are discussed in terms of the spin-state/orbital ordering of Co3+ ions.Comment: 4 page

    The alternatively spliced fibronectin CS1 isoform regulates IL-17A levels and mechanical allodynia after peripheral nerve injury.

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    BackgroundMechanical pain hypersensitivity associated with physical trauma to peripheral nerve depends on T-helper (Th) cells expressing the algesic cytokine, interleukin (IL)-17A. Fibronectin (FN) isoform alternatively spliced within the IIICS region encoding the 25-residue-long connecting segment 1 (CS1) regulates T cell recruitment to the sites of inflammation. Herein, we analyzed the role of CS1-containing FN (FN-CS1) in IL-17A expression and pain after peripheral nerve damage.MethodsMass spectrometry, immunoblotting, and FN-CS1-specific immunofluorescence analyses were employed to examine FN expression after chronic constriction injury (CCI) in rat sciatic nerves. The acute intra-sciatic nerve injection of the synthetic CS1 peptide (a competitive inhibitor of the FN-CS1/α4 integrin binding) was used to elucidate the functional significance of FN-CS1 in mechanical and thermal pain hypersensitivity and IL-17A expression (by quantitative Taqman RT-PCR) after CCI. The CS1 peptide effects were analyzed in cultured primary Schwann cells, the major source of FN-CS1 in CCI nerves.ResultsFollowing CCI, FN expression in sciatic nerve increased with the dominant FN-CS1 deposition in endothelial cells, Schwann cells, and macrophages. Acute CS1 therapy attenuated mechanical allodynia (pain from innocuous stimulation) but not thermal hyperalgesia and reduced the levels of IL-17A expression in the injured nerve. CS1 peptide inhibited the LPS- or starvation-stimulated activation of the stress ERK/MAPK pathway in cultured Schwann cells.ConclusionsAfter physical trauma to the peripheral nerve, FN-CS1 contributes to mechanical pain hypersensitivity by increasing the number of IL-17A-expressing (presumably, Th17) cells. CS1 peptide therapy can be developed for pharmacological control of neuropathic pain

    On finite-difference approximations for normalized Bellman equations

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    A class of stochastic optimal control problems involving optimal stopping is considered. Methods of Krylov are adapted to investigate the numerical solutions of the corresponding normalized Bellman equations and to estimate the rate of convergence of finite difference approximations for the optimal reward functions.Comment: 36 pages, ArXiv version updated to the version accepted in Appl. Math. Opti

    Influence of Co3+^{3+} spin-state on optical properties of LaCoO3_3 and HoCoO3_3

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    Optical properties of the isoelectronic compounds LaCoO3_3 and HoCoO3_3 has been experimentally and theoretically investigated. We've measured the real ϵ1(ω)\epsilon_1(\omega) and imaginary ϵ2(ω)\epsilon_2(\omega) parts of the dielectric function, reflectance R(ω)R(\omega) and optical conductivity at room temperature. The shift of the most pronounced spectral features to the high energy region on 0.3 eV associated with larger distortions due to the smaller rare earth ionic radii in HoCoO3_3 in comparison with LaCoO3_3 was observed. Also there was found an enhancement of absorption intensity in the range 1.3-2.3 eV in all kinds of spectra in HoCoO3_3, which can be attributed basing on the results of LDA+U calculations to the different spin-states of Co3+^{3+} ion in these compounds. The shift of the onset of the absorption from less than 0.1 eV in LaCoO3_3 to 0.7 eV in HoCoO3_3 and an absorption intensity enhancement in a narrow spectral range 1.2-2.6 eV in HoCoO3_3 are clearly seen from the calculated convolution of partial densities of states obtained in the LDA+U approach. Such changes are assumed to be induced by the different Co3+^{3+} spin-state in these compounds at room temperature.Comment: 10 pages, 3 figure

    Structural effects in UO2_2 thin films irradiated with fission-energy Xe ions

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    Uranium dioxide thin films have been successfully grown on LSAT (Al10_{10}La3_3O51_{51}Sr14_{14}Ta7_7) substrates by reactive magnetron sputtering. Irradiation by 92 MeV 129^{129}Xe23+^{23+} ions to simulate fission damage that occurs within nuclear fuels caused microstructural and crystallographic changes. Initially flat and continuous thin films were produced by magnetron sputtering with a root mean square roughness of 0.35 nm determined by AFM. After irradiation, this roughness increased to 60-70 nm, with the films developing discrete microstructural features: small grains (~3 μ\mum), along with larger circular (up to 40 μ\mum) and linear formations with non-uniform composition according to the SEM, AFM and EDX results. The irradiation caused significant restructuring of the UO2_2 films that was manifested in significant filmsubstrate mixing, observed through EDX analysis. Diffusion of Al from the substrate into the film in unirradiated samples was also observed.Engineering and Physical Sciences Research Council (Grant ID: EP/ I036400/1), Radioactive Waste Management Ltd (formerly the Radioactive Waste Management Directorate of the UK Nuclear Decommissioning Authority, contract NPO004411A-EPS02), Russian Foundation for Basic Research (projects 13-03-90916), CSAR, Grand Accelélérateur National d’Ions Lourds (GANIL) Caen France, French Network EMIR, CIMAP-CIRIL, M.V.Lomonosov Moscow State University Program of Development, CKP FMI IPCE RA
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