615 research outputs found
Courtship Behavior and Detection of Female Receptivity in the Parasitoid Wasp Urolepis rufipes
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
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
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
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Constraining the nuclear gluon distribution in processes at RHIC
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 (high energy) is
completely undefined. In this paper we analyze the possibility of constraining
the nuclear effects present in 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
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
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, , are considered:
the potential proportional to the inverse of the polar distance, i.e.,
, and the potential proportional to this distance, i.e.,
. 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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