50,775 research outputs found
Construction and performance of a novel capture-mark-release moth trap
Mark-recapture studies can provide important information about moth movement as well as habitat preference across a landscape, but to date, such studies tend to be species-specific or require labor-intensive methodologies. To address this challenge, we designed a capture-mark-release-trap (CMRT) featuring a cooling unit attached to a black light trap. The CMRT captures and incapacitates moths throughout the night until the morning, when they can be marked on-site and released. Moths captured with the CMRT during summer of 2016 had a recapture rate of 1.6%, similar to those of previous studies. Importantly, because moths are immobilized by the CMRT, they can be handled and marked with ease, reducing the opportunities to damage specimens prior to release. The CMRT trap can capture a wide array of moth species and may facilitate an increase in the monitoring of moth movement across landscapes
Optimal payload rate limit algorithm for zero-G manipulators
An algorithm for continuously computing safe maximum relative velocities for two bodies joined by a manipulator is discussed. The maximum velocities are such that if the brakes are applied at that instant, the ensuing travel between the bodies will be less than or equal to a predetermined amount. An improvement in the way this limit is computed for space manipulators is shown. The new method is explained, test cases are posed, and the results of these tests are displayed and discussed
Preparation of heterocyclic block copolymer from perfluoroalkylene oxide alpha, omega-diamidoximes
Diamidoxime monomers are intermolecularly and thermally condensed to form a heat and chemical resistant polymer containing 1,2,4-oxadiazole linkages with identical bivalent organic radicals or any combination of bivalent organic radicals selected from the group consisting of -(CX(sub 2))p-, wherein P ranges from 2 to 8 when X is fluorine and 2 to 18 when X is hydrogen, chlorine, nitro or aryl; arylene; and an oligometric or polymeric radical prepared by reacting a dicarboxylic acid halide with a fluorinated epoxide and having the formula: (CFY(OCF(sub 2)CFY)sub m)O(CX(sub 2))(sub p)O(CFYCF(sub 2)O)(sub n)CFY wherein Y is flourine or tryifluoromethyl, X is nitro, aryl, hydrogen, chlorine or fluorine, preferably the latter, p ranges from 1 to 18 and m+n ranges from 2 to 7
Effect of disorder studied with ferromagnetic resonance for arrays of tangentially magnetized sub-micron Permalloy discs fabricated by nanosphere lithography
Tangentially magnetized trigonal arrays of sub-micron Permalloy discs are
characterized with ferromagnetic resonance to determine the possible
contributions to frequency and linewidth from array disorder. Each array is
fabricated by a water-surface self-assembly lithographic technique, and
consists of a large trigonal array of 700 nm diameter magnetic discs. Each
array is characterized by a different degree of ordering. Two modes are present
in the ferromagnetic resonance spectra: a large amplitude, `fundamental' mode
and a lower amplitude mode at higher field. Angular dependence of the resonance
field in a very well ordered array is found to be negligible for both modes.
The relationship between resonance frequency and applied magnetic field is
found to be uncorrelated with array disorder. Linewidth is found to increase
with increasing array disorder
H{\alpha} Imaging of Nearby Seyfert Host Galaxies
We used narrowband interference filters with the CCD imaging camera on the
Nickel 1.0 meter telescope at Lick Observatory to observe 31 nearby (z < 0.03)
Seyfert galaxies in the 12 {\mu}m Active Galaxy Sample. We obtained pure
emission line images of each galaxy in order to separate H{\alpha} emission
from the nucleus from that of the host galaxy. The extended H{\alpha} emission
is expected to be powered by newly formed hot stars, and correlates well with
other indicators of current star formation in these galaxies: 7.7 {\mu}m PAH,
far-infrared, and radio luminosity. Relative to what would be expected from
recent star formation, there is a 0.8 dex excess of radio emission in our
Seyfert galaxies. The nuclear H{\alpha} luminosity is dominated by the AGN, and
is correlated with the hard X-ray luminosity. There is an upward offset of 1
dex in this correlation for the Seyfert 1s due to a strong contribution from
the Broad Line Region. We found a correlation between star formation rate and
AGN luminosity. In spite of selection effects, we concluded that the absence of
bright Seyfert nuclei in galaxies with low SFRs is real, albeit only weakly
significant. We used our measured spatial distributions of H{\alpha} emission
to determine what these Seyfert galaxies would look like when observed through
fixed apertures at high redshifts. Although all would be detectable emission
line galaxies at any redshift, most would appear dominated by HII region
emission. Only the most luminous AGN would still be identified at z~0.3.Comment: 13 pages, 11 figures, accepted for publication in Ap
Forced patterns near a Turing-Hopf bifurcation
We study time-periodic forcing of spatially-extended patterns near a
Turing-Hopf bifurcation point. A symmetry-based normal form analysis yields
several predictions, including that (i) weak forcing near the intrinsic Hopf
frequency enhances or suppresses the Turing amplitude by an amount that scales
quadratically with the forcing strength, and (ii) the strongest effect is seen
for forcing that is detuned from the Hopf frequency. To apply our results to
specific models, we perform a perturbation analysis on general two-component
reaction-diffusion systems, which reveals whether the forcing suppresses or
enhances the spatial pattern. For the suppressing case, our results explain
features of previous experiments on the CDIMA chemical reaction. However, we
also find examples of the enhancing case, which has not yet been observed in
experiment. Numerical simulations verify the predicted dependence on the
forcing parameters.Comment: 4 pages, 4 figure
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