1,156 research outputs found

    Monitoring Southern Flying Squirrel Populations with Nest Boxes

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    Author Institution: Division of Natural Sciences and Mathematics, Friends University ; Department of Biological Sciences, Wichita State UniversityEvaluating the practicality, economic, and sampling efficiency of potential monitoring programs is a first step in validation. Thus, we established a system of nest boxes in southeast Ohio to evaluate the feasibility of using a system of nest boxes to monitor changes in southern flying squirrel (Glaucomys volans) populations. We recorded the time of box placement until first usage and types of use by flying squirrels as an indicator of presence as well as nest box occupancy trends on a month-to-month basis to assess usage patterns and productivity. Using monitoring results from 4 years, we evaluated alternative survey sampling techniques for occupancy and determined sample sizes necessary to estimate occupancy within specified relative bounds. We also studied the cost of establishing a nest box system and monitoring nest box use. At low nest box occupancy (9.4%), sample size necessary to monitor trend would be extreme (431 boxes for 30% relative bound), but sample size is not restrictive when occupancy rates exceed 17% (211 boxes to achieve 20% relative bound). Monitoring combined spring and summer litter sizes in November or December as a measure of recruitment would require a smaller effort to achieve a tighter relative bound (10%). Assumptions relating these demographic parameters to habitat change or disturbance still must be tested before the systematic placement of nest boxes can be considered the optimum approach to monitor southern flying squirrel response as measured by changes in population density or recruitment

    Social and Spatial Relationships of Coyote Families and Neighboring Coyotes

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    Responses of White-Footed Mice and Meadow Voles to Flyovers of an Aerial Predator Silhouette

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    Author Institution: Department of Zoology, The Ohio State University; Department of Poultry and Wildlife Sciences, University of NebraskaThe response of white-footed mice and meadow voles to a stylized hawk model pulled overhead was studied. Behavior such as looking up and following the path of the model, immobility, and/or entering a nest can was observed and statistically analyzed. Overall responsiveness peaked as the model passed directly overhead. Stationary models elicited fewer instances of immobility than moving models while significantly increasing the number of white-footed mice that entered nest cans. Meadow voles were more likely to move about the 36 x 20 x 15 cm cage, but not into nest cans, during stop-go flyovers than during non-stop flyovers

    Pion photoproduction on the nucleon in the quark model

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    We present a detailed quark-model study of pion photoproduction within the effective Lagrangian approach. Cross sections and single-polarization observables are investigated for the four charge channels, γpπ+n\gamma p\to \pi^+ n, γnπp\gamma n\to \pi^- p, γpπ0p\gamma p\to \pi^0 p, and γnπ0n\gamma n\to \pi^0 n. Leaving the πNΔ\pi N\Delta coupling strength to be a free parameter, we obtain a reasonably consistent description of these four channels from threshold to the first resonance region. Within this effective Lagrangian approach, strongly constrainted by the quark model, we consider the issue of double-counting which may occur if additional {\it t}-channel contributions are included.Comment: Revtex, 35 pages, 16 eps figures; version to appear on PR

    Inhibitor binding mode and allosteric regulation of Na+-glucose symporters.

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    Sodium-dependent glucose transporters (SGLTs) exploit sodium gradients to transport sugars across the plasma membrane. Due to their role in renal sugar reabsorption, SGLTs are targets for the treatment of type 2 diabetes. Current therapeutics are phlorizin derivatives that contain a sugar moiety bound to an aromatic aglycon tail. Here, we develop structural models of human SGLT1/2 in complex with inhibitors by combining computational and functional studies. Inhibitors bind with the sugar moiety in the sugar pocket and the aglycon tail in the extracellular vestibule. The binding poses corroborate mutagenesis studies and suggest a partial closure of the outer gate upon binding. The models also reveal a putative Na+ binding site in hSGLT1 whose disruption reduces the transport stoichiometry to the value observed in hSGLT2 and increases inhibition by aglycon tails. Our work demonstrates that subtype selectivity arises from Na+-regulated outer gate closure and a variable region in extracellular loop EL5

    Photon Structure and Quantum Fluctuation

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    Photon structure derives from quantum fluctuation in quantum field theory to fermion and anti-fermion, and has been an experimentally established feature of electrodynamics since the discovery of the positron. In hadronic physics, the observation of factorisable photon structure is similarly a fundamental test of the quantum field theory Quantum Chromodynamics (QCD). An overview of measurements of hadronic photon structure in e+e- and ep interactions is presented, and comparison made with theoretical expectation, drawing on the essential features of photon fluctuation into quark and anti-quark in QCD.Comment: 29 pages, 15 figures, to appear in Philosophical Transactions of the Royal Society of London (Series A: Mathematical, Physical and Engineering Sciences

    An SU(3) model for octet baryon and meson fragmentation

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    The production of the octet of baryons and mesons in e^+ e^- collisions is analysed, based on considerations of SU(3) symmetry and a simple model for SU(3) symmetry breaking in fragmentation functions. All fragmentation functions, D_q^h(x, Q^2), describing the fragmentation of quarks into a member of the baryon octet (and similarly for fragmentation into members of the meson octet) are expressed in terms of three SU(3) symmetric functions, \alpha(x, Q^2), \beta(x, Q^2), and \gamma(x, Q^2). With the introduction of an SU(3) breaking parameter, \lambda, the model is successful in describing hadroproduction data at the Z pole. The fragmentation functions are then evolved using leading order evolution equations and good fits to currently available data at 34 GeV and at 161 GeV are obtained.Comment: 24 pages LaTeX file including 11 postscript figure file

    Experiences with a risk based meat inspection standard in pigs

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    The European Union legislation provides several possibilities to modernize meat inspection. Improvement of food safety by active contribution of food business operators in the supply chain being responsible for food safety is envisaged in these new standards

    A New 5 Flavour NLO Analysis and Parametrizations of Parton Distributions of the Real Photon

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    New, radiatively generated, NLO quark (u,d,s,c,b) and gluon densities in a real, unpolarized photon are presented. We perform three global fits, based on the NLO DGLAP evolution equations for Q^2>1 GeV^2, to all the available structure function F_2^gamma(x,Q^2) data. As in our previous LO analysis we utilize two theoretical approaches. Two models, denoted as FFNS_{CJK}1 & 2 NLO, adopt the so-called Fixed Flavour-Number Scheme for calculation of the heavy-quark contributions to F_2^gamma(x,Q^2), the CJK NLO model applies the ACOT(chi) scheme. We examine the results of our fits by a comparison with the LEP data for the Q^2 dependence of the F_2^gamma, averaged over various x-regions, and the F_2,c^gamma. Grid parametrizations of the parton densities for all fits are provided.Comment: 49 pages, 27 postscript figures; FORTRAN programs available at http://www.fuw.edu.pl/~pjank/param.htm

    Leading particle effect, inelasticity and the connection between average multiplicities in {\bf e+ee^+e^-} and {\bf pppp} processes

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    The Regge-Mueller formalism is used to describe the inclusive spectrum of the proton in ppp p collisions. From such a description the energy dependences of both average inelasticity and leading proton multiplicity are calculated. These quantities are then used to establish the connection between the average charged particle multiplicities measured in {\bf e+ee^+e^-} and {\bf pp/pˉppp/{\bar p}p} processes. The description obtained for the leading proton cross section implies that Feynman scaling is strongly violated only at the extreme values of xFx_F, that is at the central region (xF0x_F \approx 0) and at the diffraction region (xF1x_F \approx 1), while it is approximately observed in the intermediate region of the spectrum.Comment: 20 pages, 10 figures, to be published in Physical Review
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