79,435 research outputs found
Light Trap Records of \u3ci\u3ePhyllophaga\u3c/i\u3e (Coleoptera: Scarabaeidae) in Wisconsin, 1984-1987
Phyllophaga adults (June beetles) were surveyed from 1984 through 1987 at five locations in Wisconsin using black light traps. Data were collected at each location for three consecutive years. A total of 9,259 specimens representing 13 species were collected during the survey. Species captured, sex ratios, and flight periods for abundant species were recorded for each location. Species abundance differed from previous surveys of Phyllophaga in Wisconsin. Possible reasons for observed shifts in species abundance are discussed
Index statistical properties of sparse random graphs
Using the replica method, we develop an analytical approach to compute the
characteristic function for the probability that a
large adjacency matrix of sparse random graphs has eigenvalues
below a threshold . The method allows to determine, in principle, all
moments of , from which the typical sample to sample
fluctuations can be fully characterized. For random graph models with localized
eigenvectors, we show that the index variance scales linearly with
for , with a model-dependent prefactor that can be exactly
calculated. Explicit results are discussed for Erd\"os-R\'enyi and regular
random graphs, both exhibiting a prefactor with a non-monotonic behavior as a
function of . These results contrast with rotationally invariant
random matrices, where the index variance scales only as , with an
universal prefactor that is independent of . Numerical diagonalization
results confirm the exactness of our approach and, in addition, strongly
support the Gaussian nature of the index fluctuations.Comment: 10 pages, 5 figure
On the Flow Curve of Colloids Presenting Shear-Induced Phase Transitions
This work deals with the evaluation of the flow curve of colloidal systems
that develop fluid phases with different mechanical properties, namely
shear-banding fluids. The problem involved is that, as different fluid phases
coexist in the flow domain of the rheometric cell, measured data cannot be
directly converted into rheometric functions. In order to handle this problem,
a shear stress vs. shear rate constitutive relation is introduced to interpret
the steady state flow curves. The relation derives from a phenomenological
description of structural changes, and involves the possibility of multivalued
shear rates under a given shear stress. Numerical predictions satisfactorily
match up to experimental data of wormlike micellar solutions. A crucial aspect
is the adequate computation of the shear rate function from raw data measured
in the rheometric cell.Comment: 12 page
Floquet Analysis of Atom Optics Tunneling Experiments
Dynamical tunneling has been observed in atom optics experiments by two
groups. We show that the experimental results are extremely well described by
time-periodic Hamiltonians with momentum quantized in units of the atomic
recoil. The observed tunneling has a well defined period when only two Floquet
states dominate the dynamics. Beat frequencies are observed when three Floquet
states dominate. We find frequencies which match those observed in both
experiments. The dynamical origin of the dominant Floquet states is identified.Comment: Accepted in Physical Review
Residents\u27 Perceptions And Attitudes Towards Native American Gaming (NAG) In Kansas: Demographics, Policies & Future Development
This study applies a tourism model developed by Perdue, Long, and Allen ( 1990) to investigate residents\u27 perceptions of Native American Gambling in Kansas. A survey was administered to 1038 households, on a population proportionate basis, in Brown County (35 .65% ), Doniphan County (25.30% ), and Jackson County (39.05% ). Results indicated several relationships among perceived impacts of NAG development, including the respondent\u27s gender, gaming trips, age, employment status, and income level. Additionally, this study identified an association or dependence between the resident\u27s perceived future of the community and support for additional NAG development, support for restrictive NAG development policies, and support for additional taxes
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