641 research outputs found

    The Effect of an In-season Weight Training Program on the Muscular Strength of Intercollegiate Football Players

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    Intercollegiate football has become highly competitive over the past decade. As new records are set each year, offensively as well as defensively, it is imperative that players maintain a high level of strength throughout the competitive season. Ample investigations have been conducted in off-season weight training; however, there are few investigations pertaining to the use of a weight training program during the competitive season. McKay believes that while a weight training program must develop strength and endurance in the muscles used in playing the game, the program must not reduce the players’ reflexes or speed. At one time, in-season weight training was regarded as an inappropriate practice. Capen stated that exercise with weights would produce “muscle tightness.” Chic also observed that many coaches have associated weight training with “muscle boundness,” but he could find no scientific evidence to support this theory. Interest in the use of an in-season weight training program at the college level in growing; however, information related to the specific effects f this type of training in extremely limited. At least one writer, Juvenal, has suggested that with no attention given to strength training during a football season, players will experience a decrement in strength as the season progresses. Guyton supported this view when he noted that muscles not used for one to two months can decrease to one-half their normal size. With this decrease in girth, there is a proportionate reduction in muscular strength. But supporting data are scarece and in view of this paucity of data, the present researcher conducted an investigation to determine whether an in-season weight training program might influence the strength of intercollegiate football players as the competitive season progressed. The purpose of this study was to determine the effect of an in-season weight training program in selected measures of strength of intercollegiate football players during the competitive season

    Theory of Shubnikov--De Haas Oscillations Around the ν=1/2\nu=1/2 Filling Factor of the Landau Level: Effect of Gauge Field Fluctuations

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    We present a theory of magnetooscillations around the ν=1/2\nu =1/2 Landau level filling factor based on a model with a fluctuating Chern--Simons field. The quasiclassical treatment of the problem is appropriate and leads to an unconventional exp[(π/ωcτ1/2)4]\exp\left[-(\pi/\omega_c\tau^*_{1/2})^4\right] behavior of the amplitude of oscillations. This result is in good qualitative agreement with available experimental data.Comment: Revtex, 4 pages, 1 figure attached as PostScript fil

    A Coding Variant in the Gene Bardet-Biedl Syndrome 4 (BBS4) Is Associated with a Novel Form of Canine Progressive Retinal Atrophy

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    Progressive retinal atrophy is a common cause of blindness in the dog and affects >100 breeds. It is characterized by gradual vision loss that occurs due to the degeneration of photoreceptor cells in the retina. Similar to the human counterpart retinitis pigmentosa, the canine disorder is clinically and genetically heterogeneous and the underlying cause remains unknown for many cases. We use a positional candidate gene approach to identify putative variants in the Hungarian Puli breed using genotyping data of 14 family-based samples (CanineHD BeadChip array, Illumina) and whole-genome sequencing data of two proband and two parental samples (Illumina HiSeq 2000). A single nonsense SNP in exon 2 of BBS4 (c.58A > T, p.Lys20*) was identified following filtering of high quality variants. This allele is highly associated (P-CHISQ = 3.425e(-14), n = 103) and segregates perfectly with progressive retinal atrophy in the Hungarian Puli. In humans, BBS4 is known to cause Bardet-Biedl syndrome which includes a retinitis pigmentosa phenotype. From the observed coding change we expect that no functional BBS4 can be produced in the affected dogs. We identified canine phenotypes comparable with Bbs4-null mice including obesity and spermatozoa flagella defects. Knockout mice fail to form spermatozoa flagella. In the affected Hungarian Puli spermatozoa flagella are present, however a large proportion of sperm are morphologically abnormal andPeer reviewe

    Antibody quality and protection from lethal ebola virus challenge in nonhuman primates immunized with rabies virus based bivalent vaccine.

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    We have previously described the generation of a novel Ebola virus (EBOV) vaccine platform based on (a) replication-competent rabies virus (RABV), (b) replication-deficient RABV, or (c) chemically inactivated RABV expressing EBOV glycoprotein (GP). Mouse studies demonstrated safety, immunogenicity, and protective efficacy of these live or inactivated RABV/EBOV vaccines. Here, we evaluated these vaccines in nonhuman primates. Our results indicate that all three vaccines do induce potent immune responses against both RABV and EBOV, while the protection of immunized animals against EBOV was largely dependent on the quality of humoral immune response against EBOV GP. We also determined if the induced antibodies against EBOV GP differ in their target, affinity, or the isotype. Our results show that IgG1-biased humoral responses as well as high levels of GP-specific antibodies were beneficial for the control of EBOV infection after immunization. These results further support the concept that a successful EBOV vaccine needs to induce strong antibodies against EBOV. We also showed that a dual vaccine against RABV and filoviruses is achievable; therefore addressing concerns for the marketability of this urgently needed vaccine

    Quantum Hall Fluids on the Haldane Sphere: A Diffusion Monte Carlo Study

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    A generalized diffusion Monte Carlo method for solving the many-body Schr\"odinger equation on curved manifolds is introduced and used to perform a `fixed-phase' simulation of the fractional quantum Hall effect on the Haldane sphere. This new method is used to study the effect of Landau level mixing on the ν=1/3\nu=1/3 energy gap and the relative stability of spin-polarized and spin-reversed quasielectron excitations.Comment: 13 pages, Revtex + psfig, figures include

    Quantum Boltzmann equation of composite fermions interacting with a gauge field

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    We derive the quantum Boltzmann equation (QBE) of composite fermions at/near the ν=1/2\nu = 1/2 state using the non-equilibrium Green's function technique. The lowest order perturbative correction to the self-energy due to the strong gauge field fluctuations suggests that there is no well defined Landau-quasi-particle. Therefore, we cannot assume the existence of the Landau-quasi-particles {\it a priori} in the derivation of the QBE. Using an alternative formulation, we derive the QBE for the generalized Fermi surface displacement which corresponds to the local variation of the chemical potential in momentum space. {}From this QBE, one can understand in a unified fashion the Fermi-liquid behaviors of the density-density and the current-current correlation functions at ν=1/2\nu = 1/2 (in the long wave length and the low frequency limits) and the singular behavior of the energy gap obtained from the finite temperature activation behavior of the compressibility near ν=1/2\nu = 1/2. Implications of these results to the recent experiments are also discussed.Comment: 44 pages, Plain Tex, 5 figures (ps files) available upon reques

    The Haldane-Rezayi Quantum Hall State and Magnetic Flux

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    We consider the general abelian background configurations for the Haldane-Rezayi quantum Hall state. We determine the stable configurations to be the ones with the spontaneous flux of (Z+1/2)ϕ0(\Z+1/2) \phi_0 with ϕ0=hc/e\phi_0 = hc/e. This gives the physical mechanism by which the edge theory of the state becomes identical to the one for the 331 state. It also provides a new experimental consequence which can be tested in the enigmatic ν=5/2\nu=5/2 plateau in a single layer system.Comment: RevTex, 5 pages, 2 figures. v2:minor corrections. v4: published version. Discussion on the thermodynamic limit adde

    Design of chemical space networks incorporating compound distance relationships

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    Networks, in which nodes represent compounds and edges pairwise similarity relationships, are used as coordinate-free representations of chemical space. So-called chemical space networks (CSNs) provide intuitive access to structural relationships within compound data sets and can be annotated with activity information. However, in such similarity-based networks, distances between compounds are typically determined for layout purposes and clarity and have no chemical meaning. By contrast, inter-compound distances as a measure of dissimilarity can be directly obtained from coordinate-based representations of chemical space. Herein, we introduce a CSN variant that incorporates compound distance relationships and thus further increases the information content of compound networks. The design was facilitated by adapting the Kamada-Kawai algorithm. Kamada-Kawai networks are the first CSNs that are based on numerical similarity measures, but do not depend on chosen similarity threshold values

    Influence of gauge-field fluctuations on composite fermions near the half-filled state

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    Taking into account the transverse gauge field fluctuations, which interact with composite fermions, we examine the finite temperature compressibility of the fermions as a function of an effective magnetic field ΔB=B2nehc/e\Delta B = B - 2 n_e hc/e (nen_e is the density of electrons) near the half-filled state. It is shown that, after including the lowest order gauge field correction, the compressibility goes as nμeΔωc/2T(1+A(η)η1(Δωc)21+ηT){\partial n \over \partial \mu} \propto e^{- \Delta \omega_c / 2 T} \left ( 1 + {A (\eta) \over \eta - 1} {(\Delta \omega_c)^{2 \over 1 + \eta} \over T} \right ) for TΔωcT \ll \Delta \omega_c, where Δωc=eΔBmc\Delta \omega_c = {e \Delta B \over mc}. Here we assume that the interaction between the fermions is given by v(q)=V0/q2η (1η2)v ({\bf q}) = V_0 / q^{2 - \eta} \ (1 \le \eta \le 2), where A(η)A (\eta) is a η\eta dependent constant. This result can be interpreted as a divergent correction to the activation energy gap and is consistent with the divergent renormalization of the effective mass of the composite fermions.Comment: Plain Tex, 24 pages, 5 figures available upon reques

    Spin-Orbit Interaction Enhanced Fractional Quantum Hall States in the Second Landau Level

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    We study the fractional quantum Hall effect at filling fractions 7/3 and 5/2 in the presence of the spin-orbit interaction, using the exact diagonalization method and the density matrix renormalization group (DMRG) method in a spherical geometry. Trial wave functions at these fillings are the Laughlin state and the Moore-Reed-Pfaffian state. The ground state excitation energy gaps and pair-correlation functions at fractional filling factor 7/3 and 5/2 in the second Landau level are calculated. We find that the spin-orbit interaction stabilizes the fractional quantum Hall states.Comment: 4pages, 4figure
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