1,483 research outputs found

    Proteomic analysis of the rat ovary following chronic low-dose exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

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    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitously distributed endocrine-disrupting chemical and reproductive toxicant. In order to elucidate low-dose TCDD-mediated effects on reproductive or endocrine functions, female Sprague-Dawley rats were orally administered various concentrations (20, 50, or 125 ng/kg once weekly) TCDD for 29 wk. A proteomic analysis of the ovaries by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry showed distinct changes in the levels of several proteins that are relevant markers of TCDD toxicity. Serum estradiol (E2) levels of TCDD-treated animals were markedly lower than control. There were no significant differences in bone mineral density (BMD) of femurs. The body weight of the 125-ng/kg TCDD group was significantly decreased relative to control and there was also a significant reduction in absolute and relative ovarian weights. Expressions of selenium binding protein 2, glutathione S-transferase mu type 3, Lrpap1 protein, NADPH, and peptidylprolyl isomerase D were upregulated, while prohibitin and N-ethylmaleimide-sensitive factor expression levels were downregulated. Data provide further insight into the mechanisms by which TCDD disrupts ovarian function by indicating which differential protein expressions following low-dose TCDD exposure

    Metodología para la Creación de una Interfaz Cerebro-Computador Aplicada a la Identificación de la Intención de Movimiento

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    ResumenLas Interfaces Cerebro-Computador proporcionan un canal para enviar órdenes al mundo exterior haciendo uso de medidas electrofisiológicas de la actividad cerebral. En este artículo se presenta la combinación de un método de selección de características y un algoritmo de clasificación probabilístico para construir el modelo predictivo de la intención anticipada de movimiento voluntario de pacientes con temblor a partir de un solo ensayo. Los resultados obtenidos muestran una potencial de discriminación del 70%, una tasa de error aceptable (6.6%) y una rápida respuesta (cada 250ms), lo que indica que esta combinación es una buena base para la construcción de ICCs que no requieran entrenamiento del usuario de forma personalizada, asíncrona y adaptativa

    Production Optimization,Molecular Characterization and Biological Activities of Exopolysaccharides from Xylaria nigripes

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    The optimal culture conditions of exopolysaccharides (EPS) production in submerged culture medium by Xylaria nigripes were determined using orthogonal matrix method. The optimal medium (per liter) EPS was 60.0 g L–1 maltose, 1.0 g L–1 peptone, 5 mmol L–1 KH2PO4, and initial pH 7.0 at 28 oC. In the optimal culture medium, the maximum EPS production was 11.967 g L–1 in shake flask. Two groups of EPSs (designated as Fr-I and Fr-II) were obtained from the culture filtrates by size exclusion chromatography (SEC), and their molecular characteristics were examined by a multiangle laser-light scattering (MALLS) and refractive index (RI) detector system. The weight-average molar masses of Fr-I and Fr-II of EPS were determined to be 6.327104 and 1.478104 g mol–1, respectively. The SEC/MALLS analysis revealed that the molecular formation of Fr-I is of nearly globular shape. Furthermore, the experiments in vitro indicated that X. nigripes EPS exhibited high antioxidative effects though its antitumour activity was limited

    Darboux Transformations for a Lax Integrable System in 2n2n-Dimensions

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    A 2n2n-dimensional Lax integrable system is proposed by a set of specific spectral problems. It contains Takasaki equations, the self-dual Yang-Mills equations and its integrable hierarchy as examples. An explicit formulation of Darboux transformations is established for this Lax integrable system. The Vandermonde and generalized Cauchy determinant formulas lead to a description for deriving explicit solutions and thus some rational and analytic solutions are obtained.Comment: Latex, 14 pages, to be published in Lett. Math. Phy

    A systematic review of tools designed for teacher proxy-report of children’s physical literacy or constituting elements

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    Abstract Background Physical literacy (PL) in childhood is essential for a healthy active lifestyle, with teachers playing a critical role in guiding its development. Teachers can assist children to acquire the skills, confidence, and creativity required to perform diverse movements and physical activities. However, to detect and directly intervene on the aspects of children’s PL that are suboptimal, teachers require valid and reliable measures. This systematic review critically evaluates the psychometric properties of teacher proxy-report instruments for assessing one or more of the 30 elements within the four domains (physical, psychological, cognitive, social) of the Australian Physical Literacy Framework (APLF), in children aged 5–12 years. Secondary aims were to: examine alignment of each measure (and relevant items) with the APLF and provide recommendations for teachers in assessing PL. Methods Seven electronic databases (Academic Search Complete, CINAHL Complete, Education Source, Global Health, MEDLINE Complete, PsycINFO, and SPORTDiscus) were systematically searched originally in October 2019, with an updated search in April 2021. Eligible studies were peer-reviewed English language publications that sampled a population of children with mean age between 5 and 12 years and focused on developing and evaluating at least one psychometric property of a teacher proxy-report instrument for assessing one or more of the 30 APLF elements. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance was followed for the conduct and reporting of this review. The methodological quality of included studies and quality of psychometric properties of identified tools were evaluated using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidance. Alignment of each measure (and relevant items) with the APLF domains and 30 elements was appraised. Results Database searches generated 61,412 citations; reduced to 41 studies that evaluated the psychometric properties of 24 teacher proxy-report tools. Six tools were classified as single domain measures (i.e. assessing a single domain of the APLF), eleven as dual-domain measures, and seven as tri-domain measures. No single tool captured all four domains and 30 elements of the APLF. Tools contained items that aligned with all physical, psychological, and social elements; however, four cognitive elements were not addressed by any measure. No tool was assessed for all nine psychometric properties outlined by COSMIN. Included studies reported a median of 3 out of nine psychometric properties. Most reported psychometric properties were construct validity (n = 32; 78% of studies), structural validity (n = 26; 63% of studies), and internal consistency (n = 25; 61% of studies). There was underreporting of content validity, cross-cultural validity, measurement error, and responsiveness. Psychometric data across tools were mostly indeterminate for construct validity, structural validity, and internal consistency. Conclusions There is limited evidence to fully support the use of a specific teacher proxy-report tool in practice. Further psychometric testing and detailed reporting of methodological aspects in future validity and reliability studies is needed. Tools have been designed to assess some elements of the framework. However, no comprehensive teacher proxy-report tool exists to assess all 30 elements of the APLF, demonstrating the need for a new tool. It is our recommendation that such tools be developed and psychometrically tested. Trial registration This systematic review was registered in the PROSPERO international prospective register of systematic reviews, with registration number CRD42019130936

    A self-consistent method to analyze the effects of the positive Q-value neutron transfers on fusion

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    AbstractConsidering the present limitation of the need for external parameters to describe the nucleus–nucleus potential and the couplings in the coupled-channels calculations, this work introduces an improved method without adjustable parameter to overcome the limitation and then sort out the positive Q-value neutron transfers (PQNT) effects based on the CCFULL calculations. The corresponding analysis for Ca+Ca, S,Ca+Sn, and S,Ca+Zr provides a reliable proof and a quantitative evaluation for the residual enhancement (RE) related to PQNT. In addition, the RE for S32,Ca40+Zr94 shows an unexpected larger enhancement than S32,Ca40+Zr96 despite the similar multi-neutron transfer Q-values. This method should rather strictly test the fusion models and be helpful for excavating the underlying physics

    Radiative Decay of Υ\Upsilon into a Scalar Glueball

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    We study the radiative decay of Υ\Upsilon into a scalar glueball ΥγGs\Upsilon \to \gamma G_s using QCD factorization. We find that for this process the non-perturbative effects can be factorized into a matrix element well defined in non-relativistic QCD (NRQCD) and the gluon distribution amplitude. The same NRQCD matrix element appears also in leptonic decay of Υ\Upsilon and therefore can be determined from data. In the asymptotic limit the gluon distribution amplitude is known up to a normalization constant. Using a QCD sum-rule calculation for the normalization constant, we obtain Br(ΥγGs)Br(\Upsilon \to \gamma G_s) to be in the range (12)×103(1\sim 2)\times 10^{-3}. We also discuss some of the implications for Υγfi\Upsilon \to \gamma f_i decays. Near future data from CLEO-III can provide crucial information about scalar glueball properties.Comment: RevTex, 12 pages no figures. Several numerical errors correcte

    Phenomenological Tests of Supersymmetric A_4 Family Symmetry Model of Neutrino Mass

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    Recently Babu, Ma and Valle proposed a model of quark and lepton mixing based on A4A_4 symmetry. Within this model the lepton and slepton mixings are intimately related. We perform a numerical study in order to derive the slepton masses and mixings in agreement with present data from neutrino physics. We show that, starting from three-fold degeneracy of the neutrino masses at a high energy scale, a viable low energy neutrino mass matrix can indeed be obtained in agreement with constraints on lepton flavour violating μ\mu and τ\tau decays. The resulting slepton spectrum must necessarily include at least one mass below 200 GeV which can be produced at the LHC. The predictions for the absolute Majorana neutrino mass scale m00.3m_0 \geq 0.3 eV ensure that the model will be tested by future cosmological tests and ββ0ν\beta\beta_{0\nu} searches. Rates for lepton flavour violating processes ji+γ\ell_j \to \ell_i + \gamma in the range of sensitivity of current experiments are typical in the model, with BR(\mu \to e \gamma) \gsim 10^{-15} and the lower bound BR(τμγ)>109(\tau \to \mu \gamma) > 10^{-9}. To first approximation, the model leads to maximal leptonic CP violation in neutrino oscillations.Comment: 23 pages, 7 figure

    Single gluino production in the R-parity lepton number violating MSSM at the LHC

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    We examine the RpR_{p}-violating signal of single gluino production associated with a charged lepton or neutrino at the large hadron collider (LHC), in the model of R-parity relaxed supersymmetric model. If the parameters in the /Rp{\rlap/R}_p supersymmetric interactions are not too small, and the mass of gluino is considered in the range from several GeV (as the Lightest Supersymmetric Particle) to 800 GeV, the cross section of the single gluino production via Drell-Yan processes can be in the order of 10210310^2 \sim 10^3 femto barn, and that via gluon fusion in the order of 10110310^{-1} \sim 10^3 femto barn. If the gluino decay can be well detected in the CERN LHC, this process provides a prospective way to probe supersymmetry and RpR_p violation.Comment: LaTex, 22 pages, 5 EPS file

    Deviation of Atmospheric Mixing from Maximal and Structure in the Leptonic Flavor Sector

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    I attempt to quantify how far from maximal one should expect the atmospheric mixing angle to be given a neutrino mass-matrix that leads, at zeroth order, to a nu_3 mass-eigenstate that is 0% nu_e, 50% nu_mu, and 50% nu_tau. This is done by assuming that the solar mass-squared difference is induced by an "anarchical" first order perturbation, an approach than can naturally lead to experimentally allowed values for all oscillation parameters. In particular, both |cos 2theta_atm| (the measure for the deviation of atmospheric mixing from maximal) and |U_e3| are of order sqrt(Delta m^2_sol/Delta m^2_atm) in the case of a normal neutrino mass-hierarchy, or of order Delta m^2_sol/Delta m^2_atm in the case of an inverted one. Hence, if any of the textures analyzed here has anything to do with reality, next-generation neutrino experiments can see a nonzero cos 2theta_atm in the case of a normal mass-hierarchy, while in the case of an inverted mass-hierarchy only neutrino factories should be able to see a deviation of sin^2 2theta_atm from 1.Comment: 12 pages, no figures, references and acknowledgments adde
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