1,853 research outputs found

    Bias Voltage and Temperature Dependence of Hot Electron Magnetotransport

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    We present a qualitative model study of energy and temperature dependence of hot electron magnetotransport. This model calculations are based on a simple argument that the inelastic scattering strength of hot electrons is strongly spin and energy dependent in the ferromagnets. Since there is no clear experimental data to compare with this model calculations, we are not able to extract clear physics from this model calculations. However, interestingly this calculations display that the magnetocurrent increases with bias voltage showing high magnetocurrent if spin dependent imaginary part of proper self energy effect has a substantial contribution to the hot electron magnetotransport. Along with that, the hot electron magnetotransport is strongly influence by the hot electron spin polarization at finite temperatures

    Shaping citizenship in the classroom:Peer influences on moral disengagement, social goals, and a sense of peer community

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    Despite the important role of peers in the social process of classroom citizenship, the peer influence related to moral disengagement, social goals, and a sense of peer community remain unclear. To this end, it was examined to what extent youth become similar to their friends in moral disengagement, social goals, and a sense of peer community. Participants were 283 South Korean third to sixth graders (Mage = 9.60 years, SD = 0.97; 51.6% girls) who completed an online survey for moral disengagement, social goals, the sense of peer community and friendship network across the beginning (Time 1) and end (Time 2) of the school semester (September to December). Longitudinal social network analyses indicated that youth became more similar to their friends concerning moral disengagement and a sense of peer community, but did not select friends based on these aspects. The strength of these influence effects varied in terms of different levels of these aspects. Specifically, youth were more likely to become similar to their friends at lower levels of moral disengagement. Youth tended to be similar to the friends' level of sense of peer community. This tendency was relatively strong at the lowest and the highest levels of a sense of peer community. Future research should address the role of friendship in shaping classroom citizenship and the importance of classroom daily teaching practice in youth citizenship development

    Broilers fed a low protein diet supplemented with synthetic amino acids maintained growth performance and retained intestinal integrity while reducing nitrogen excretion when raised under poor sanitary conditions

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    The present study investigated the effects of supplementing a low protein (LP) diet supplemented with key essential amino acids (AA) to broilers on growth performance, intestinal tract function, blood metabolites, and nitrogen excretion when the animals were maintained under various sanitary conditions for 35 D after hatching. Three hundred eighty-four one-day-old male broilers (Ross 308) were randomly allotted to groups that received one of 6 dietary treatments in a 2 × 3 factorial arrangement (i.e., 2 environmental conditions and 3 dietary treatments) to give 8 replicates per treatment. Broilers were challenged with 2 environmental conditions (sanitary vs. poor sanitary). The dietary treatments were (1) high protein (HP) diet, (2) LP diet, and (3) LP diet with synthetic key essential AA (LPA): the LP diet was supplemented with synthetic AA up to the required levels for broilers. On day 14, birds consumed the LP diet impaired growth performance compared with those fed the HP diet, while the average daily weight gain-to-feed conversion ratio of birds fed the LPA diet improved to the level of birds fed the HP diet under poor sanitary conditions (P < 0.05). Broilers raised under poor sanitary conditions and fed the LP diet displayed higher (P < 0.05) zonula occludens (ZO-1) expression on day 14 than broilers fed either the HP or LPA diet. Under sanitary conditions, birds fed HP and LPA diets showed higher villus height and crypt depth compared with those of broilers fed the LP diet on day 35. Moreover, broilers raised in the poor sanitary environment had higher (P < 0.05) serum endotoxins than those raised in the sanitary environment. Broilers fed the LPA diet showed reduced (P < 0.05) nitrogen excretion on days 14 and 35 compared with those fed the LP and HP diets independent of the environment. In conclusion, the LPA diet did not impair growth performance under poor sanitary conditions for 14 D after hatch while resulting in lower nitrogen excretion in any environment conditions throughout the experiment

    Surface Instability in Windblown Sand

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    We investigate the formation of ripples on the surface of windblown sand based on the one-dimensional model of Nishimori and Ouchi [Phys. Rev. Lett. 71, 197 (1993)], which contains the processes of saltation and grain relaxation. We carry out a nonlinear analysis to determine the propagation speed of the restabilized ripple patterns, and the amplitudes and phases of their first, second, and third harmonics. The agreement between the theory and our numerical simulations is excellent near the onset of instability. We also determine the Eckhaus boundary, outside which the steady ripple patterns are unstable.Comment: 23 pages, 8 figure

    Nonmonotonic inelastic tunneling spectra due to surface spin excitations in ferromagnetic junctions

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    The paper addresses inelastic spin-flip tunneling accompanied by surface spin excitations (magnons) in ferromagnetic junctions. The inelastic tunneling current is proportional to the magnon density of states which is energy-independent for the surface waves and, for this reason, cannot account for the bias-voltage dependence of the observed inelastic tunneling spectra. This paper shows that the bias-voltage dependence of the tunneling spectra can arise from the tunneling matrix elements of the electron-magnon interaction. These matrix elements are derived from the Coulomb exchange interaction using the itinerant-electron model of magnon-assisted tunneling. The results for the inelastic tunneling spectra, based on the nonequilibrium Green's function calculations, are presented for both parallel and antiparallel magnetizations in the ferromagnetic leads.Comment: 9 pages, 4 figures, version as publishe

    A nondiagrammatic calculation of the Rho parameter from heavy fermions

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    A simple nondiagrammatic evaluation of the nondecoupling effect of heavy fermions on the Veltman's Rho parameter is presented in detail. This calculation is based on the path integral approach, the electroweak chiral Lagrangian formalism, and the Schwinger proper time method.Comment: 11 page

    Bullying as a Developmental Precursor to Sexual and Dating Violence Across Adolescence: Decade in Review

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    Adolescent bullying continues to be a major focus of scholarship across the globe. This article reviews research from 2010 to 2021 with a particular focus on longitudinal studies of the bully–sexual violence pathway (BSVP), where bullying serves as a precursor for sexual violence (SV) (e.g., sexual harassment, sexual coercion, and sexual assault) and teen dating violence via individual and socio-contextual mediators. Articles reviewed consisted of a total of 505, which included 17 meta-analyses and systematic reviews. Databases used for the search were Academic Search Complete, Education Full Text (H. W. Wilson), ERIC, National Criminal Justice Reference Service Abstracts, PsycINFO, PubMed (Medline), and Social Sciences Abstracts (H. W. Wilson). In total, 107 peer-reviewed articles were included in this review. Potential mechanisms underlying the BSVP include social dominance orientation, exposure to sexual education, and alcohol use. Several school-based intervention approaches have evidenced marginal success in reducing rates of bullying and SV by targeting factors undergirding both behaviors. The efficacy of international prevention approaches is summarized. Gaps in the literature are identified and future research is proposed

    Bundle and annulus CHF correlations applicable for near critical pressure region

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    Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.Bundle and annulus CHF correlations are developed by using CHF experimental data from the Freon R-134a Thermal Hydraulic Experimental Loop developed at KAERI. The CHF data are in the range of the pressure of 3200 ~ 4030 kPa (Critical pressure of R-134a = 4059 kPa), the mass flux 150∼1500 kg/m2s, and the inlet subcooling 40 ~ 70 kJ/kg. We obtained local T/H values using a subchannel analysis code and produced CHF correlations for the matrix subchannel, coldwall subchannel and annulus channel, respectively. A subchannel code, The MATRA-α IBM PC version, is used to obtain the local conditions in a hot subchannel (CHF observed channel) in the 5x5 bundle geometry. All the CHF experimental data are successfully calculated by the present correlations with good prediction performance. The prediction accuracy of the correlations is not distorted by much in any of the ranges of the independent parameters. The bundle CHF correlations could help one to conceptually design a SCWR, by adopting a fluidto- fluid modeling technique for a CHF near a critical pressure.mp201

    Liquid-Solid Transition of Hard Spheres Under Gravity

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    We investigate the liquid-solid transition of two dimensional hard spheres in the presence of gravity. We determine the transition temperature and the fraction of particles in the solid regime as a function of temperature via Even-Driven molecular dynamics simulations and compare them with the theoretical predictions. We then examine the configurational statistics of a vibrating bed from the view point of the liquid-solid transition by explicitly determining the transition temperature and the effective temperature, T, of the bed, and present a relation between T and the vibration strength.Comment: 14 total pages, 4 figure
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