435 research outputs found
Correlates of Northern Bobwhite Distribution and Abundance with Land-Use Characteristics in Kansas
County-level agricultural statistics were correlated with Rural Mail Carrier Survey reports and Breeding Bird Survey data for northern bobwhite (Colinus virginianus) in Kansas. Results indicate statewide analysis is feasible when temporally congruent data exist for both agricultural land-use characteristics and bobwhite distribution and abundance. Interpretations of these results can be useful in state or regional analysis and in the development of habitat management strategies for bobwhite. The Multiple Response Permutation Procedure identified 16 land-use variables, 3 soil variables, and 1 spatial variable that were significantly different in counties where bobwhite were present from counties where they were absent. Sixteen land-use variables, 5 soil variables, and 3 spatial variables distinguished between counties where bobwhite abundance was classified as high or low. Spearman\u27s rank correlation identified 8 soil variables, 14 land-use variables, and 3 spatial variables that were significantly correlated with bobwhite abundance. Least absolute deviation regression analysis revealed 4 land-use variables that were significantly correlated (Agreement= 0.48, P = 0.0001) with bobwhite abundance
Discovery of a ~1 Hz quasi-periodic oscillation in the low-mass X-ray binary 4U 1746-37
We have discovered a ~1 Hz quasi-periodic oscillation (QPO) in the persistent
X-ray emission and during type I X-ray bursts of the globular cluster source,
dipper and low-mass X-ray binary (LMXB) 4U 1746-37. The QPO properties resemble
those of QPOs found recently in the LMXB dippers 4U 1323-62, and EXO 0748-676,
which makes 4U 1746-37 the third source known to exhibit this type of QPOs. We
present evidence for X-ray spectral changes in this source similar to those
observed in LMXBs referred to as atoll sources. We detect two states, a low
intensity and spectrally hard state, and a higher intensity and spectrally soft
state. This may explain the different spectral characteristics reported for 4U
1746-37 earlier. The high intensity state resembles the banana branch state of
atoll sources. The QPOs are only seen in the low intensity state, and are
absent when the source is in the banana branch. This strongly suggests that
either the accretion disk or an extended central source change shape between
the low intensity state and the banana branch. Twelve bursts were detected, of
which 5 took place while the source was on the banana branch and 7 when the
source was in the low intensity state. The bursts occurring on the banana
branch had an e-folding time ~3 times longer than those which occurred in the
low intensity state. Whereas previously detected dips showed only a decrease in
count rate of ~15%, we found in one observation a dip in which the count rate
dropped from ~200 counts per second to ~20 counts per second. This dip lasted
only ~250 seconds, during which clear spectral hardening occured. This is the
first time strong evidence for spectral changes during a dip are reported for
this source.Comment: 17 pages, accepted for publication in Ap
On cap sets and the group-theoretic approach to matrix multiplication
In 2003, Cohn and Umans described a framework for proving upper bounds on the exponent ω of matrix multiplication by reducing matrix multiplication to group algebra multiplication, and in 2005 Cohn, Kleinberg, Szegedy, and Umans proposed specific conjectures for how to obtain ω = 2. In this paper we rule out obtaining ω = 2 in this framework from abelian groups of bounded exponent. To do this we bound the size of tricolored sum-free sets in such groups, extending the breakthrough results of Croot, Lev, Pach, Ellenberg, and Gijswijt on cap sets. As a byproduct of our proof, we show that a variant of tensor rank due to Tao gives a quantitative understanding of the notion of unstable tensor from geometric invariant theory
The Grizzly, November 30, 1999
Bears Take a Beating Against Rowan in the NCAA Division III Tournament: Final Score 55-0 • Judicial Board Finds Two Students Guilty • Judicial Board: How the System Works • S.T.A.R.: Providing Help for Victims of Sexual Assaults • Ursinus\u27 Political Link to the Collegeville Community: Dr. Goetz • Experiencing the Trappe Tavern • Student Says Sayonara to UC and Opts for Off-Campus Experience • Letters to the Editors: Violence on Campus; The White Agenda; A Case of Race • Bears Gain First Victory in NCAA Division III Playoffs • Rowan Overpowers Ursinus in Second Round of Playoffs • Fan-Vans Travel to Bridgewater, Mass. • Ursinus Swimming Fights Hard Against Gettysburghttps://digitalcommons.ursinus.edu/grizzlynews/1453/thumbnail.jp
Enhancing Neutrino Event Reconstruction with Pixel-Based 3D Readout for Liquid Argon Time Projection Chambers
In this paper we explore the potential improvements in neutrino event
reconstruction that a 3D pixelated readout could offer over a 2D projective
wire readout for liquid argon time projection chambers. We simulate and study
events in two generic, idealized detector configurations for these two designs,
classifying events in each sample with deep convolutional neural networks to
compare the best 2D results to the best 3D results. In almost all cases we find
that the 3D readout provides better reconstruction efficiency and purity than
the 2D projective wire readout, with the advantages of 3D being particularly
evident in more complex topologies, such as electron neutrino charged current
events. We conclude that the use of a 3D pixelated detector could significantly
enhance the reach and impact of future liquid argon TPC experiments physics
program, such as DUNE
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