2,772 research outputs found
HABITAT UTILIZATION BY THE TEXAS HORNED LIZARD (PHRYNOSOMA CORNUTUM) FROM TWO SITES IN CENTRAL TEXAS
The Texas Horned Lizard (Phrynosoma cornutum) is found in a variety of habitats. Although several studies have been conducted on habitat use by this species, none have been performed in central Texas, a more mesic habitat than most of those previously studied. This area is of special interest because horned lizard populations have been experiencing sharp declines in central Texas over the last approximately 50 years. We collected habitat data at two sites in central Texas, Camp Bowie and Blue Mountain Peak Ranch. Microhabitat data included canopy cover and ground cover from digitized photographs of Daubenmire quadrats; macrohabitat variables included vegetation height and length, cactus height, soil penetrability, woody plant species richness, tree density, tree diameter at breast height (DBH), and density of ant mounds collected along 100-m by 2-m transects. Similar patterns of habitat use were observed between the two sites. At Blue Mountain Peak Ranch, lizards appeared to be located in areas with a diversity of ground cover types, as observed in previous studies. At Camp Bowie, vegetation encroachment limited lizards in some areas to the use of roads and road margins. Implementation of prescribed burns or other vegetation management could create the preferred ground cover mosaic at such sites
Directed percolation in aerodynamics: resolving laminar separation bubble on airfoils
In nature, phase transitions prevail amongst inherently different systems,
while frequently showing a universal behavior at their critical point. As a
fundamental phenomenon of fluid mechanics, recent studies suggested
laminar-turbulent transition belonging to the universality class of directed
percolation. Beyond, no indication was yet found that directed percolation is
encountered in technical relevant fluid mechanics. Here, we present first
evidence that the onset of a laminar separation bubble on an airfoil can be
well characterized employing the directed percolation model on high fidelity
particle image velocimetry data. In an extensive analysis, we show that the
obtained critical exponents are robust against parameter fluctuations, namely
threshold of turbulence intensity that distinguishes between ambient flow and
laminar separation bubble. Our findings indicate a comprehensive significance
of percolation models in fluid mechanics beyond fundamental flow phenomena, in
particular, it enables the precise determination of the transition point of the
laminar separation bubble. This opens a broad variety of new fields of
application, ranging from experimental airfoil aerodynamics to computational
fluid dynamics.Comment: 8 pages, 11 figure
Pulse shape discrimination performance of Inverted Coaxial Ge detectors
We report on the characterization of two inverted coaxial Ge detectors in the
context of being employed in future Ge neutrinoless double beta
() decay experiments. It is an advantage that such detectors
can be produced with bigger Ge mass as compared to the planar Broad Energy Ge
detectors (BEGe) that are currently used in the GERDA decay
experiment. This will result in lower background for the search of
decay due to a reduction of cables, electronics and holders.
The measured resolution near the Ge Q-value at 2039 keV is 2.5 keV and
their pulse-shape characteristics are similar to BEGe-detectors. It is
concluded that this type of Ge-detector is suitable for usage in Ge
decay experiments
Holiday Lights Create Light Pollution and Become Ecological Trap for Eastern Fox Squirrels: Case Study on a University Campus
Ecological light pollution is now recognized as a significant source of ecosystem alteration. We documented that holiday lights are a seasonal source of light pollution that constitute an ecological trap for eastern fox squirrels (Sciurus niger). Texas A&M University-Kingsville (TAMUK) wildlife students surveyed a 2-km walking transect 5 times per month each month for the relative abundance and diel behavior of eastern fox squirrels and feral cats (Felis catus) on the TAMUK campus during 2018–2019. Eastern fox squirrels exhibited diurnal behaviors throughout the year but extended their foraging behavior nearly 4 hours after sunset with the addition of holiday lights. Feral cats and owls (Strigiformes) exhibited diurnal and nocturnal behaviors but conducted the majority of their hunting during crepuscular hours. We documented that monthly squirrel mortality increased 7-fold with the addition of holiday lights, possibly due to the extension of foraging time by squirrels. Although seasonal lighting is intended to be festive for humans, it can have negative consequences for eastern fox squirrels. Educating the public concerning the issue of light pollution on wildlife species is needed because the majority of the public appears unaware that bright lights can negatively alter wildlife behaviors. Reducing light intensity by either using less outdoor lights or perhaps using colored lights rather than clear white bulbs may lessen the negative effect on foraging behavior of squirrels
Beyond the helium buffer: C-12(2)- rotational cooling in cold traps with H-2 as a partner gas: interaction forces and quantum dynamics
The scattering cross-sections and corresponding rate coefficients for rotationally inelastic collisions of 12 C−2 (2Σ+g) with H2 (1Σ+g) are presented over a broad range of cold-trap temperatures. They have been calculated using quantum scattering theory that employs a new ab initio potential energy surface. The rate coefficients for the inelastic processes in the anionic partner are used to model the thermalisation dynamics of 12 C−2 using H2 as a buffer gas, a trap partner which is found here to be far more efficient than the typical buffer gas He and even more so than when using Ar as a partner gas. The microscopic physics underlying these findings is discussed in some detail. We additionally compute and discuss 12 C−2 quadrupole transitions by spontaneous emission and use the newly computed rates to show that the anion's rotational levels should be in local thermal equilibrium at typical interstellar conditions
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