1,166 research outputs found
Geophysical and Biological Reconnaissance of Rock Habitats in Western Camden Bay, Beaufort Sea, Alaska
This report presents the results of a 10-day geophysical and
biological survey in western Camden Bay, in the Alaskan Beaufort Sea.
The primary objective of this survey was to confirm the existence of
boulders and cobbles on the seafloor as reported by Barnes (1981, 1982).
The survey area extended from the eastern edge of the Canning River (mud
flat area) to Kangigivik Point and seaward to the 14m contour line
(Fig. 1). A solid boundary of pack ice prevented any survey work
seaward of the 14m contour. We had proposed to examine the seabed to
the 18m contour.This work was
supported by the Bureau of Land Management through an interagency
agreement with the National Oceanic and Atmospheric Administration,
under which a multiyear program responding to needs of petroleum
development of the Alaskan Continental Shelf is managed by the Outer
Continental Shelf Environmental Assessment Program (OCSEAP) office
Decoherence and thermalization dynamics of a quantum oscillator
We introduce the quantitative measures characterizing the rates of
decoherence and thermalization of quantum systems. We study the time evolution
of these measures in the case of a quantum harmonic oscillator whose relaxation
is described in the framework of the standard master equation, for various
initial states (coherent, `cat', squeezed and number). We establish the
conditions under which the true decoherence measure can be approximated by the
linear entropy . We show that at low temperatures and for
highly excited initial states the decoherence process consists of three
distinct stages with quite different time scales. In particular, the `cat'
states preserve 50% of the initial coherence for a long time interval which
increases logarithmically with increase of the initial energy.Comment: 24 pages, LaTex, 8 ps figures, accepted for publication in J. Opt.
v-K-data for silica from interrupted lifetime measurements
Different methods were applied so far in order to determine subcritical crack growth for silica. Mostly, fracture mechanics standard tests with macro cracks were used for this purpose. In this report, we evaluated the subcritical crack growth curves from interrupted lifetime tests on silica bending specimens containing small natural flaws. The resulting v-K-curve showed crack growth rates down to 10 m/s indicating a threshold for subcritical crack growth at
K0.31 MPa
In the plot of v=f(K/K) slight material differences could be eliminated and suitable agreement with macro-crack results by Wiederhorn and Bolz [1] on DCB-specimens and Michalske et al. [2] on DCDC-specimens could be stated
Olfactory attractants and parity affect prenatal androgens and territoriality of coyote breeding pairs
Hormones are fundamental mediators of personality traits intimately linked with reproductive success. Hence, alterations to endocrine factors may dramatically affect individual behavior that has subsequent fitness consequences. Yet it is unclear how hormonal or behavioral traits change with environmental stressors or over multiple reproductive opportunities, particularly for biparental fauna. To simulate an environmental stressor, we exposed captive coyote (Canis latrans) pairs to novel coyote odor attractants (i.e. commercial scent lures) midgestation to influence territorial behaviors, fecal glucocorticoid (FGMs) and fecal androgen metabolites (FAMs). In addition, we observed coyote pairs as first-time and experienced breeders to assess the influence of parity on our measures. Treatment pairs received the odors four times over a 20-day period, while control pairs received water. Odor-treated pairs scent-marked (e.g. urinated, ground scratched) and investigated odors more frequently than control pairs, and had higher FAMs when odors were provided. Pairs had higher FAMs as first-time versus experienced breeders, indicating that parity also affected androgen production during gestation. Moreover, repeatability in scent-marking behaviors corresponded with FGMs and FAMs, implying that coyote territoriality during gestation is underpinned by individually-specific hormone profiles. Our results suggest coyote androgens during gestation are sensitive to conspecific olfactory stimuli and prior breeding experience. Consequently, fluctuations in social or other environmental stimuli as well as increasing parity may acutely affect coyote traits essential to reproductive success
Process Intensification in a Double-Pipe Reactor with Additively Manufactured Internal Inserts
The polycondensation reaction to produce polydextrose can be intensified by using micro-process engineering. Fluid Guiding Elements are additively manufactured internal inserts that have already shown their potential to intensify heat transfer in double-pipe heat exchangers. This study investigated the intensification of the polydextrose yield when these internal inserts were used. Different reactor lengths and internal inserts geometries, as well as different operating conditions, were analyzed. The experiments showed that the reactant concentration had no effect on the product yield. Furthermore, it was shown that the process could be intensified at higher temperatures, with relatively low residence times and lower pressures. It was confirmed that the good heat transfer characteristics of the internal inserts allow them to continuously evaporate water during the reaction and to further reach the required reaction temperature, thus shifting the equilibrium towards the desired product. These findings are of special significance for the optimization of the polycondensation reaction of polydextrose
Olfactory attractants and parity affect prenatal androgens and territoriality of coyote breeding pairs
Hormones are fundamental mediators of personality traits intimately linked with reproductive success. Hence, alterations to endocrine factors may dramatically affect individual behavior that has subsequent fitness consequences. Yet it is unclear how hormonal or behavioral traits change with environmental stressors or over multiple reproductive opportunities, particularly for biparental fauna. To simulate an environmental stressor, we exposed captive coyote (Canis latrans) pairs to novel coyote odor attractants (i.e. commercial scent lures) midgestation to influence territorial behaviors, fecal glucocorticoid (FGMs) and fecal androgen metabolites (FAMs). In addition, we observed coyote pairs as first-time and experienced breeders to assess the influence of parity on our measures. Treatment pairs received the odors four times over a 20-day period, while control pairs received water. Odor-treated pairs scent-marked (e.g. urinated, ground scratched) and investigated odors more frequently than control pairs, and had higher FAMs when odors were provided. Pairs had higher FAMs as first-time versus experienced breeders, indicating that parity also affected androgen production during gestation. Moreover, repeatability in scent-marking behaviors corresponded with FGMs and FAMs, implying that coyote territoriality during gestation is underpinned by individually-specific hormone profiles. Our results suggest coyote androgens during gestation are sensitive to conspecific olfactory stimuli and prior breeding experience. Consequently, fluctuations in social or other environmental stimuli as well as increasing parity may acutely affect coyote traits essential to reproductive success
Investigation of techniques to measure cortisol and testosterone concentrations in coyote hair
Long-term noninvasive sampling for endangered or elusive species is particularly difficult due to the challenge of collecting fecal samples before hormone metabolite desiccation, as well as the difficulty in collecting a large enough sample size from all individuals. Hair samples may provide an environmentally stable alternative that provides a long-term assessment of stress and reproductive hormone profiles for captive, zoo, and wild mammals. Here, we extracted and analyzed both cortisol and testosterone in coyote (Canis latrans) hair for the first time. We collected samples from 5-week old coyote pups (six female, six male) housed at the USDA-NWRC Predator Research Facility in Millville, UT. Each individual pup was shaved in six different locations to assess variation in concentrations by body region. We found that pup hair cortisol (F5,57.1 = 0.47, p = 0.80) and testosterone concentrations (F5,60 = 1.03, p = 0.41) did not differ as a function of body region. Male pups generally had higher cortisol concentrations than females (males = 17.71 ± 0.85 ng/g, females = 15.48 ± 0.24 ng/g; F1,57.0 = 5.06, p = 0.028). Comparatively, we did not find any differences between male and female testosterone concentrations (males = 2.86 ± 0.17 ng/g, females = 3.12 ± 0.21 ng/g; F1,60 = 1.42, p = 0.24). These techniques represent an attractive method in describing long-term stress and reproductive profiles of captive, zoo-housed, and wild mammal populations
Investigation of the local environment of SnO2 in an applied magnetic field
This paper presents the results of time-differential perturbed gammaâgamma angular correlation measurements of SnO2 thin films carried out in an applied magnetic field. The measurements were performed upon the implantation of Fe at 80 keV and 111In (111Cd) at 160 keV. The samples were further characterized by energydispersive X-ray spectroscopy. The hyperfine parameters were studied at room temperature with and without an applied magnetic field. The results indicate the presence of two distinct local environments for the probe nuclei. Both occupy a paramagnetic state and correspond to a substitutional Sn site in the rutile phase of SnO2
with different numbers of electrons added to SnO2:Cd0. In addition, the crystal homogeneity of the site 1 increases upon applying the magnetic field
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