1,746 research outputs found

    Non-diffractive mechanisms in the ϕ\phi meson photoproduction on nucleons

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    We examine the non-diffractive mechanisms in the ϕ\phi meson photoproduction from threshold up to a few GeV using an effective Lagrangian in a constituent quark model. The new data from CLAS at large angles can be consistently accounted for in terms of {\it s}- and {\it u}-channel processes. Isotopic effects arising from the reactions γpϕp\gamma p\to \phi p and γnϕn\gamma n\to \phi n, are investigated by comparing the cross sections and polarized beam asymmetries. Our result highlights an experimental means of studying non-diffractive mechanisms in ϕ\phi meson photoproduction.Comment: 4 eps figures, version accepted by Phys. Lett.

    Theory of proximity effect in superconductor/ferromagnet heterostructures

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    We present a microscopic theory of proximity effect in the ferromagnet/superconductor/ferromagnet (F/S/F) nanostructures where S is s-wave low-T_c superconductor and F's are layers of 3d transition ferromagnetic metal. Our approach is based on the solution of Gor'kov equations for the normal and anomalous Green's functions together with a self-consistent evaluation of the superconducting order parameter. We take into account the elastic spin-conserving scattering of the electrons assuming s-wave scattering in the S layer and s-d scattering in the F layers. In accordance with the previous quasiclassical theories, we found that due to exchange field in the ferromagnet the anomalous Green's function F(z) exhibits the damping oscillations in the F-layer as a function of distance z from the S/F interface. In the given model a half of period of oscillations is determined by the length \xi_m^0 = \pi v_F/E_ex, where v_F is the Fermi velocity and E_ex is the exchange field, while damping is governed by the length l_0 = (1/l_{\uparrow} + 1/l_{\downarrow})^{-1} with l_{\uparrow} and l_{\downarrow} being spin-dependent mean free paths in the ferromagnet. The superconducting transition temperature T_c(d_F) of the F/S/F trilayer shows the damping oscillations as a function of the F-layer thickness d_F with period \xi_F = \pi/\sqrt{m E_ex}, where m is the effective electron mass. We show that strong spin-conserving scattering either in the superconductor or in the ferromagnet significantly suppresses these oscillations. The calculated T_c(d_F) dependences are compared with existing experimental data for Fe/Nb/Fe trilayers and Nb/Co multilayers.Comment: 13 pages, REVTeX4, 8 PS-figures; improved version, submitted to PR

    Influence of season of birth, sex and paternal line on growth performance and carcass traits in pigs

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    Participants in the pig production industry focus on feed and feed additives to improve growth performance and meat quality of pigs. Consequently, the Rural Development Administration of the Republic of Korea produced a new paternal line to improve economic traits in pigs. However, there is an absence of information on pig traits with regard to season and sex, and a comparison between the new paternal line and past paternal lines. Therefore, the authors conducted this study to investigate the influence of season of birth, sex and paternal line on growth performance and carcass traits in pigs. A total of 2888 piglets ((Landrace × Yorkshire) × Darby Duroc (DD) or Chookjin Duroc (CD)) with an average age of three weeks were tested for 22 weeks during the four season of the year (spring 608 piglets, summer 404 piglets, autumn 576 piglets and winter 1300 piglets). The bodyweights (BW) of individual pig were recorded, and feed consumption was recorded at weeks 2, 12 and 22, to determine growth performance. At reaching market weight, backfat thickness was determined at the last rib area. Meat was graded according to the criteria of the slaughterhouse. There were no significant differences in growth performance and carcass traits between sexes. The CD line crossbred pig had a significant higher BW at 16 weeks, and higher carcass trait values at 22 weeks than the DD line. During weeks 8 to 16 the CD line crossbred pigs showed a tendency of an increased average daily gain (ADG) and gain : feed (G : F) ratio compared with the DD line. Furthermore, pigs born in spring had significant lower ADG, average daily feed intake (ADFI) and carcass trait values than born in the other seasons. In conclusion, the new paternal line (Chookjin Duroc) improved growth performance and carcass traits compare with the DD line.Keywords: sex, growth, terminal sire, meat quality, backfat thicknes

    Clinical effect of IRT-5 probiotics on immune modulation of autoimmunity or alloimmunity in the eye

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    Background: Although the relation of the gut microbiota to a development of autoimmune and inflammatory diseases has been investigated in various animal models, there are limited studies that evaluate the effect of probiotics in the autoimmune eye disease. Therefore, we aimed to investigate the effect of IRT-5 probiotics consisting of Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus reuteri, Bifidobacterium bifidum, and Streptococcus thermophilus on the autoimmunity of uveitis and dry eye and alloimmunity of corneal transplantation. Methods: Experimental autoimmune uveitis was induced by subcutaneous immunization with interphotoreceptor-binding protein and intraperitoneal injection of pertussis toxin in C57BL/6 (B6) mice. For an autoimmune dry eye model, 12-weeks-old NOD.B10.H2b mice were used. Donor cornea of B6 mice was transplanted into BALB/C mice. IRT-5 probiotics or phosphate buffered saline (PBS) were administered for three weeks immediately after induction of uveitis or transplantation. The inflammation score of the retinal tissues, dry eye manifestations (corneal staining and tear secretion), and graft survival were measured in each model. The changes of T cells were evaluated in drainage lymph nodes using fluorescence-activated cell sorting. Results: Retinal histology score in IRT-5 group of uveitis was lower than that in PBS group (p = 0.045). Ocular staining score was lower (p < 0.0001) and tear secretion was higher (p < 0.0001) in the IRT-5 group of NOD.B10.H2b mice than that in the PBS group. However, the graft survival in the IRT-5 group was not different from those of PBS group. The percentage of regulatory T cells was increased in the IRT-5-treated dry eye models (p = 0.032). The percentage of CD8+IL-17hi (p = 0.027) and CD8+ interferon gamma (IFN��)hi cells (p = 0.022) were significantly decreased in the IRT-5-treated uveitis models and the percentage of CD8+IFN��hi cells was markedly reduced (p = 0.036) in IRT-5-treated dry eye model. Conclusion: Our results suggest that administration of IRT-5 probiotics may modulate clinical manifestations of autoimmunity in the eye, but not on alloimmunity of corneal transplantation. ? 2017 by the authors.112Nsciescopu

    Optical investigation on the electronic structures of Y_{2}Ru_{2}O_{7}, CaRuO_{3}, SrRuO_{3}, and Bi_{2}Ru_{2}O_{7}

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    We investigated the electronic structures of the bandwidth-controlled ruthenates, Y2_{2}Ru2_{2}O7_{7}, CaRuO3_{3}, SrRuO3_{3}, and Bi2_{2}Ru2% _{2}O7_{7}, by optical conductivity analysis in a wide energy region of 5 meV \sim 12 eV. We could assign optical transitions from the systematic changes of the spectra and by comparison with the O 1ss x-ray absorption data. We estimated some physical parameters, such as the on-site Coulomb repulsion energy and the crystal-field splitting energy. These parameters show that the 4dd orbitals should be more extended than 3dd ones. These results are also discussed in terms of the Mott-Hubbard model.Comment: 12 pages (1 table), 3 figure

    Time and Amplitude of Afterpulse Measured with a Large Size Photomultiplier Tube

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    We have studied the afterpulse of a hemispherical photomultiplier tube for an upcoming reactor neutrino experiment. The timing, the amplitude, and the rate of the afterpulse for a 10 inch photomultiplier tube were measured with a 400 MHz FADC up to 16 \ms time window after the initial signal generated by an LED light pulse. The time and amplitude correlation of the afterpulse shows several distinctive groups. We describe the dependencies of the afterpulse on the applied high voltage and the amplitude of the main light pulse. The present data could shed light upon the general mechanism of the afterpulse.Comment: 11 figure

    Modelling the prestress transfer in pre-tensioned concrete elements

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    Three models were developed to simulate the transfer of prestress force from steel to concrete in pre-tensioned concrete elements. The first is an analytical model based on the thick-walled cylinder theory and considers linear material properties for both steel and concrete. The second is an axi-symmetric finite element (FE) model with linear material properties; it is used to verify the analytical model. The third model is a three dimensional nonlinear FE model. This model considers the post-cracking behaviour of concrete as well as concrete shrinkage and the time of prestress releasing. A new expression from the analytical model is developed to estimate the transmission length as well as the stress distribution along the tendon. The paper also presents a parametric study to illustrate the impact of diameter of prestressing steel, concrete cover, concrete strength, initial prestress, section size, surface roughness of prestressing steel, time of prestress release, and the member length on the transfer of stress in pre-tensioned concrete elements

    Inhomogeneous magnetism induced in a superconductor at superconductor-ferromagnet interface

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    We study a magnetic proximity effect at superconductor (S) - ferromagnet (F) interface. It is shown that due to an exchange of electrons between the F and S metals ferromagnetic correlations extend into the superconductor, being dependent on interface parameters. We show that ferromagnetic exchange field pair breaking effect leads to a formation of subgap bands in the S layer local density of states, that accommodate only one spin-polarized quasiparticles. Equilibrium magnetization leakage into the S layer as function of SF interface quality and a value of ferromagnetic interaction have also been calculated. We show that a damped-oscillatory behavior versus distance from SF interface is a distinguished feature of the exchange-induced magnetization of the S layer.Comment: 10 pages, 7 Postscript figure

    Spontaneous Spin Polarized Currents in Superconductor-Ferromagnetic Metal Heterostructures

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    We study a simple microscopic model for thin, ferromagnetic, metallic layers on semi-infinite bulk superconductor. We find that for certain values of the exchange spliting, on the ferromagnetic side, the ground states of such structures feature spontaneously induced spin polarized currents. Using a mean-field theory, which is selfconsistent with respect to the pairing amplitude χ\chi, spin polarization m\vec{m} and the spontaneous current js\vec{j}_s, we show that not only there are Andreev bound states in the ferromagnet but when their energies EnE_n are near zero they support spontaneous currents parallel to the ferromagnetic-superconducting interface. Moreover, we demonstrate that the spin-polarization of these currents depends sensitively on the band filling.Comment: 4 pages, 5 Postscript figures (included

    Layered ferromagnet-superconductor structures: the π\pi state and proximity effects

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    We investigate clean mutilayered structures of the SFS and SFSFS type, (where the S layer is intrinsically superconducting and the F layer is ferromagnetic) through numerical solution of the self-consistent Bogoliubov-de Gennes equations for these systems. We obtain results for the pair amplitude, the local density of states, and the local magnetic moment. We find that as a function of the thickness dFd_F of the magnetic layers separating adjacent superconductors, the ground state energy varies periodically between two stable states. The first state is an ordinary "0-state", in which the order parameter has a phase difference of zero between consecutive S layers, and the second is a "π\pi-state", where the sign alternates, corresponding to a phase difference of π\pi between adjacent S layers. This behavior can be understood from simple arguments. The density of states and the local magnetic moment reflect also this periodicity.Comment: 12 pages, 10 Figure
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