1,321 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

    Effects of planform geometry on hover performance of a 2-meter-diameter model of a four-bladed rotor

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    Hover tests were conducted on three small scale rotors to evaluate the effects of blade planform taper on rotor hover performance. Tests were conducted on a rectangular swept-tip configuration, on a configuration with a 3 to 1 taper over the outboard 20 percent of the span, and on a configuration with a 5 to 1 taper over the outboard 20 percent of the blade span. The investigation covered a range of thrust coefficients from 0 to 0.0075 and a range of tip speeds from 300 to 600 ft/sec. The tests showed that both tapered configurations had better hover performance than the swept-tip rectangular configuration and that the 3 to 1 taper configuration was better than the 5 to 1 taper configuration. The test results were compared with predictions made with a prescribed wake analysis, a momentum analysis, and a simplified free wake analysis

    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

    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

    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

    Error Patterns in Apraxia of Speech

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    Clocking hadronization in relativistic heavy ion collisions with balance functions

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    A novel state of matter has been hypothesized to exist during the early stage of relativistic heavy ion collisions, with normal hadrons not appearing until several fm/c after the start of the reaction. To test this hypothesis, correlations between charges and their associated anticharges are evaluated with the use of balance functions. It is shown that late-stage hadronization is characterized by tightly correlated charge/anticharge pairs when measured as a function of relative rapidity.Comment: 5 pages, 3 figure

    Photoproduction of pions and properties of baryon resonances from a Bonn-Gatchina partial wave analysis

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    Masses, widths and photocouplings of baryon resonances are determined in a coupled-channel partial wave analysis of a large variety of data. The Bonn-Gatchina partial wave formalism is extended to include a decomposition of t- and u-exchange amplitudes into individual partial waves. The multipole transition amplitudes for γppπ0\gamma p\to p\pi^0 and γpnπ+\gamma p\to n\pi^+ are given and compared to results from other analyses.Comment: 18 pages, 14 figure
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