706 research outputs found

    Mean Field Model of Coagulation and Annihilation Reactions in a Medium of Quenched Traps: Subdiffusion

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    We present a mean field model for coagulation (A+A→AA+A\to A) and annihilation (A+A→0A+A\to 0) reactions on lattices of traps with a distribution of depths reflected in a distribution of mean escape times. The escape time from each trap is exponentially distributed about the mean for that trap, and the distribution of mean escape times is a power law. Even in the absence of reactions, the distribution of particles over sites changes with time as particles are caught in ever deeper traps, that is, the distribution exhibits aging. Our main goal is to explore whether the reactions lead to further (time dependent) changes in this distribution.Comment: 9 pages, 3 figure

    Intensity of physical education classes in adolescents

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    Se registró la frecuencia cardiaca de 182 estudiantes (97 chicos y 85 chicas) de entre 12 y 18 años durante sus clases de Educación Física. Los resultados muestran una media del 21,62±14,33% del tiempo de clase en valores MVPA (moderate to vigorous physical activity). Respecto al género, pese a no ser significativo, los mayores valores corresponden a la chicas (23,47±14,45% vs 19,99±14,10%; p=0,106). No se ha observado efecto del tipo de sesión (deportes colectivos, deportes individuales, juegos tradicionales o bailes) sobre el tiempo en valores MVPA (p>0,05; TE0.05; ES<0.020), obtaining the highest values in team sports sessions. Results show that intensity and duration of analyzed classes do not comply with recommendations to become an adequate cardiovascular exercis

    Physical Education in English. A proposal for working postural hygiene in Primary Education

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    In recent years, European Union has increased the demand for bilingual education as a tool to prepare young people in school and at work. This need has been reflected in the educational legislation of its member countries In Spain, since 2006 there is a basic competency related to foreign language learning. The Physical Education area has become an ideal means to facilitate the learning of English through play and movement. In order to facilitate the work of future teachers in the area, this article examines the teaching of Physical Education in the bilingual English. The current legislation that governs the implementation of bilingualism in schools will be presented, along with the most important methodological considerations for teaching our subject in English. Finally, in the section about practical applications, we present a circuit of activities to work postural hygiene in Primary Education. Each activity has its description in Spanish and English, along with the «teacher speech», with specific instructions to carry out in each of the exercise

    Order statistics of the trapping problem

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    When a large number N of independent diffusing particles are placed upon a site of a d-dimensional Euclidean lattice randomly occupied by a concentration c of traps, what is the m-th moment of the time t_{j,N} elapsed until the first j are trapped? An exact answer is given in terms of the probability Phi_M(t) that no particle of an initial set of M=N, N-1,..., N-j particles is trapped by time t. The Rosenstock approximation is used to evaluate Phi_M(t), and it is found that for a large range of trap concentracions the m-th moment of t_{j,N} goes as x^{-m} and its variance as x^{-2}, x being ln^{2/d} (1-c) ln N. A rigorous asymptotic expression (dominant and two corrective terms) is given for for the one-dimensional lattice.Comment: 11 pages, 7 figures, to be published in Phys. Rev.

    A model for the atomic-scale structure of a dense, nonequilibrium fluid: the homogeneous cooling state of granular fluids

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    It is shown that the equilibrium Generalized Mean Spherical Model of fluid structure may be extended to nonequilibrium states with equation of state information used in equilibrium replaced by an exact condition on the two-body distribution function. The model is applied to the homogeneous cooling state of granular fluids and upon comparison to molecular dynamics simulations is found to provide an accurate picture of the pair distribution function.Comment: 29 pages, 11 figures Revision corrects formatting of the figure

    Enhanced In Vivo Activity of Cefditoren in Pre-Immunized Mice against Penicillin-Resistant S. pneumoniae (Serotypes 6B, 19F and 23F) in a Sepsis Model

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    Background Specific antibodies are likely to be present before S. pneumoniae infection. We explored cefditoren (CDN) total and free values of serum concentrations exceeding the MIC (t>MIC) related to efficacy in a mice sepsis model, and the effect of specific gammaglobulins on in-vitro phagocytosis and in-vivo efficacy. Methodology/Principal Findings We used three pneumococcal isolates (serotype, MIC of CDN): Strain 1 (6B, 1 µg/ml), Strain 2 (19F, 2 µg/ml) and Strain 3 (23F, 4 µg/ml). Hyperimmune serum (HS) was obtained from mice immunized with heat-inactivated strains. In-vitro, phagocytosis by HS diluted 1/10 in presence/absence of sub-inhibitory concentrations was measured by flow cytometry including fluorescent bacteria and a neutrophil cell line. In-vivo dose-ranging experiments with HS (dilutions 1/2–1/16) and CDN (6.25 mg/kg–100 mg/kg tid for 48 h) were performed to determine the minimal protective dilution/dose (highest survival) and the non-protective highest dilution/dose (highest mortality: HS-np dilution and CDN-np dose) over 7 days. Efficacy of CDN-np in animals pre-immunized with HS-np (combined strategy) was explored and blood bacterial clearance determined. The CDN measured protein binding was 86.9%. In-vitro, CDN significantly increased phagocytosis (vs. HS 1/10). In non pre-immunized animals, t>MIC values for CDN of ≈35% (total) and ≈19% (free) were associated with 100% survival. Significant differences in survival were found between HS-np alone (≤20%) or CDN-np alone (≤20%) vs. the combined strategy (90%, 60% and 60% for Stains 1, 2 and 3), with t>MIC (total/free) of 22.8%/14.3%, 26.8%/16.0%, and 22.4%/12.7% for Strains 1, 2 and 3, respectively. Prior to the second dose (8 h), median bacterial counts were significantly lower in animals surviving vs. dead at day 7. Conclusions/Significance In mice (CDN protein binding similar to humans) total t>MIC values of ≈35% (≈19% free) were efficacious, with a decrease in the required values in pre-immunized animals. This reinforces that immunoprotection to overcome resistance may provide lifesaving strategies.This study was supported by an unrestricted grant from Tedec-Meiji Farma S.A., Madrid, Spain. Tedec-Meiji Farma S.A. had a role in providing reagents, materials and analysis toolsPeer reviewe

    Finite time and asymptotic behaviour of the maximal excursion of a random walk

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    We evaluate the limit distribution of the maximal excursion of a random walk in any dimension for homogeneous environments and for self-similar supports under the assumption of spherical symmetry. This distribution is obtained in closed form and is an approximation of the exact distribution comparable to that obtained by real space renormalization methods. Then we focus on the early time behaviour of this quantity. The instantaneous diffusion exponent νn\nu_n exhibits a systematic overshooting of the long time exponent. Exact results are obtained in one dimension up to third order in n−1/2n^{-1/2}. In two dimensions, on a regular lattice and on the Sierpi\'nski gasket we find numerically that the analytic scaling νn≃ν+An−ν\nu_n \simeq \nu+A n^{-\nu} holds.Comment: 9 pages, 4 figures, accepted J. Phys.

    Self-Similar Interpolation in Quantum Mechanics

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    An approach is developed for constructing simple analytical formulae accurately approximating solutions to eigenvalue problems of quantum mechanics. This approach is based on self-similar approximation theory. In order to derive interpolation formulae valid in the whole range of parameters of considered physical quantities, the self-similar renormalization procedure is complimented here by boundary conditions which define control functions guaranteeing correct asymptotic behaviour in the vicinity of boundary points. To emphasize the generality of the approach, it is illustrated by different problems that are typical for quantum mechanics, such as anharmonic oscillators, double-well potentials, and quasiresonance models with quasistationary states. In addition, the nonlinear Schr\"odinger equation is considered, for which both eigenvalues and wave functions are constructed.Comment: 1 file, 30 pages, RevTex, no figure

    7-Nitroindazole reduces L-DOPA-induced dyskinesias in non-human Parkinsonian primate

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    ©2023. This manuscript version is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Submitted, Accepted, Published, version of a Published Work that appeared in final form in Open Biology. To access the final edited and published work see https://doi.org/10.1098/rsob.22037
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