615 research outputs found

    Courtship Behavior and Detection of Female Receptivity in the Parasitoid Wasp Urolepis rufipes

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    Once a Urolepis rufipes male mounted, the female beat her antennae against his mouth and clypeus. Immediately after he swept his antennae rapidly downward and extruded his mouthparts, her abdomen rose as she opened her genital orifice. Almost simultaneously he backed up for copulation and she folded her antennae against her head. Neither her abdomen rising nor her antennal folding were essential to his backing up as determined from their timing and from experiments in which her abdomen was sealed or her antennae were removed. Females did not open their genital orifice if with a sealed-mouth male; and antennae-removed females did not open even in the few cases where untreated males extruded their mouthparts. Unlike a closely related species, females mounted by sealed-mouth males did not open in response to air from containers of mating pairs.This article is made openly accessible in part by an award from the Northern Illinois University Libraries’ Open Access Publishing Fund

    Supersymmetric solutions of PT-/non-PT-symmetric and non-Hermitian Screened Coulomb potential via Hamiltonian hierarchy inspired variational method

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    The supersymmetric solutions of PT-symmetric and Hermitian/non-Hermitian forms of quantum systems are obtained by solving the Schrodinger equation for the Exponential-Cosine Screened Coulomb potential. The Hamiltonian hierarchy inspired variational method is used to obtain the approximate energy eigenvalues and corresponding wave functions.Comment: 13 page

    The effects of grain shape and frustration in a granular column near jamming

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    We investigate the full phase diagram of a column of grains near jamming, as a function of varying levels of frustration. Frustration is modelled by the effect of two opposing fields on a grain, due respectively to grains above and below it. The resulting four dynamical regimes (ballistic, logarithmic, activated and glassy) are characterised by means of the jamming time of zero-temperature dynamics, and of the statistics of attractors reached by the latter. Shape effects are most pronounced in the cases of strong and weak frustration, and essentially disappear around a mean-field point.Comment: 17 pages, 19 figure

    Gamow-Teller Strengths for Neutrino Detectors

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    Constraining the nuclear gluon distribution in eAeA processes at RHIC

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    A systematic determination of the gluon distribution is of fundamental interest in understanding the parton structure of nuclei and the QCD dynamics. Currently, the behavior of this distribution at small xx (high energy) is completely undefined. In this paper we analyze the possibility of constraining the nuclear effects present in xgAxg^A using the inclusive observables which would be measured in the future electron-nucleus collider at RHIC. We demonstrate that the study of nuclear longitudinal and charm structure functions allows to estimate the magnitude of shadowing and antishadowing effects in the nuclear gluon distribution.Comment: 6 pages, 3 eps figure

    Spin-gravity coupling and gravity-induced quantum phases

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    External gravitational fields induce phase factors in the wave functions of particles. The phases are exact to first order in the background gravitational field, are manifestly covariant and gauge invariant and provide a useful tool for the study of spin-gravity coupling and of the optics of particles in gravitational or inertial fields. We discuss the role that spin-gravity coupling plays in particular problems.Comment: 18 pages, 1 figur

    Relativistic quantum dynamics of a charged particle in cosmic string spacetime in the presence of magnetic field and scalar potential

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    In this paper we analyze the relativistic quantum motion of charged spin-0 and spin-1/2 particles in the presence of a uniform magnetic field and scalar potentials in the cosmic string spacetime. In order to develop this analysis, we assume that the magnetic field is parallel to the string and the scalar potentials present a cylindrical symmetry with their center on the string. Two distinct configurations for the scalar potential, S(r)S(r), are considered: (i)(i) the potential proportional to the inverse of the polar distance, i.e., S1/rS\propto1/r, and (ii)(ii) the potential proportional to this distance, i.e., SrS\propto r. The energy spectra are explicitly computed for different physical situations and presented their dependences on the magnetic field strength and scalar coupling constants.Comment: New version with 20 pages and no figure. Some minor revisions and six references added. Accepted for publication in EJP
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