1,214 research outputs found

    Assessment of practicality of remote sensing techniques for a study of the effects of strip mining in Alabama

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    Because of the volume of coal produced by strip mining, the proximity of mining operations, and the diversity of mining methods (e.g. contour stripping, area stripping, multiple seam stripping, and augering, as well as underground mining), the Warrior Coal Basin seemed best suited for initial studies on the physical impact of strip mining in Alabama. Two test sites, (Cordova and Searles) representative of the various strip mining techniques and environmental problems, were chosen for intensive studies of the correlation between remote sensing and ground truth data. Efforts were eventually concentrated in the Searles Area, since it is more accessible and offers a better opportunity for study of erosional and depositional processes than the Cordova Area

    Effect of Two Week L-Arginine Supplementation on Variables Related to Endurance and Strength Performance in Collegiate Football Players

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    Background: It has been shown that a month-long supplementation period of L-arginine, coupled with exercise training, increases exercise performance more than either supplementation or exercise alone (Hambrecht et al., 2000). Purpose: The purpose of this study was to examine the effects of a shorter 2 wk L-arginine supplementation period on factors related to endurance and strength performance. Methods: Twelve collegiate football players volunteered to participate in this study. The control group (n = 6) and treatment group (n = 6) both participated in the same off-season training program that consisted of strength training 3 d/wk and agility training 2 d/wk. In addition, the treatment group received 1g of L-arginine twice daily, whereas the control group received a placebo twice daily. At the beginning of the study, participants performed a baseline bench press maximum repetitions test at 70% of their most recently recorded bench press 1 RM (MMR). The participants also performed a graded exercise test (GXT) on a cycle ergometer to volitional exhaustion. Following baseline testing, participants immediately began the supplementation period, and were retested in the MMR and the GXT after 2 wk of supplementation. The effect of supplementation on each dependent variable was determined using ANCOVA with pretests serving as the covariates. Results: ANCOVA did not reveal significant effects of L-arginine supplementation on MMR (F(1,9) = 1.71, p = 0.22), VO2max (F(1,9) = 1.08, p = 0.33), time to exhaustion in the GXT (F(1,9) = 0.19, p = 0.67) , or HRmax during the GXT (F(1,9) = 4.79, p = 0.06). Conclusion: A 2 wk supplementation period coupled with training may not be of sufficient length to improve factors related to endurance and strength performance in trained college-aged men

    Primordial Gravitational Waves From Open Inflation

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    We calculate the spectrum of gravitational waves generated during inflation in open (Ω0<1)(\Omega _0<1) inflationary models. In such models an initial epoch of old inflation solves the horizon and flatness problems, and during this first epoch of inflation the quantum state of the graviton field rapidly approaches the Bunch-Davies vacuum. Then old inflation ends by the nucleation of a single bubble, inside of which there is a shortened epoch of slow-roll inflation giving Ω0<1\Omega _0<1 today. In this paper we re-express the Bunch-Davies vacuum for the graviton field in terms of the hyperbolic modes inside the bubble and propagate these modes forward in time into the present era. We derive the expression for the contribution from these gravity waves to the cosmic microwave background anisotropy including the effect of a finite energy difference across the bubble wall.Comment: 40 pages, TEX with phyzzx macro, 5 figure

    Constraints on Type Ia Supernova Models from X-ray Spectra of Galaxy Clusters

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    We present constraints on theoretical models of Type Ia supernovae using spatially resolved ASCA X-ray spectroscopy of three galaxy clusters: Abell 496, Abell 2199 and Abell 3571. All three clusters have central iron abundance enhancements; an ensemble of abundance ratios are used to show that most of the iron in the central regions of the clusters comes from SN Ia. These observations are consistent with the suppressed galactic wind scenario proposed by Dupke and White (1999). At the center of each cluster, simultaneous analysis of spectra from all ASCA instruments shows that the nickel to iron abundance ratio (normalized by the solar ratio) is Ni/Fe ~ 4. We use the nickel to iron ratio as a discriminator between SN Ia explosion models: the Ni/Fe ratio of ejecta from the "Convective Deflagration" model W7 is consistent with the observations, while those of "delayed detonation" models are not consistent at the 90% confidence level.Comment: 20 pages, 2 figures, accepted by The Astrophysical Journa

    Description of Synthetic Model Building and Image Compositing Processes

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    Seroprevalence, Blood Chemistry, and Patterns of Canine Parvovirus, Distemper Virus, Plague, and Tularemia in Free-ranging Coyotes (\u3ci\u3eCanis latrans\u3c/i\u3e) in Northern New Mexico, USA

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    Wildlife diseases have implications for ecology, conservation, human health, and health of domestic animals. They may impact wildlife health and population dynamics. Exposure rates of coyotes (Canis latrans) to pathogens such as Yersinia pestis, the cause of plague, may reflect prevalence rates in both rodent prey and human populations. We captured coyotes in north-central New Mexico during 2005–2008 and collected blood samples for serologic surveys. We tested for antibodies against canine distemper virus (CDV, Canine morbillivirus), canine parvovirus (CPV, Carnivore protoparvovirus), plague, tularemia (Francisella tularensis), and for canine heartworm (Dirofilaria immitis) antigen. Serum biochemistry variables that fell outside reference ranges were probably related to capture stress. We detected antibodies to parvovirus in 32/32 samples (100%), and to Y. pestis in 26/31 (84%). More than half 19/32 (59%) had antibodies against CDV, and 5/31 (39%) had antibodies against F. tularensis. We did not detect any heartworm antigens (n = 9). Pathogenprevalence was similar between sexes and among the three coyote packs in the study area. Parvovirus exposure appeared to happen early in life, and prevalence of antibodies against CDV increased with increasing age class. Exposure to Y. pestis and F. tularensis occurred across all age classes. The high coyote seroprevalence rates observed for CPV, Y. pestis, and CDV may indicate high prevalence in sympatric vertebrate populations, with implications for regional wildlife conservation as well as risk to humans via zoonotic transmission

    New Constraint on Open Cold-Dark-Matter Models

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    We calculate the large-angle cross-correlation between the cosmic-microwave-background (CMB) temperature and the x-ray-background (XRB) intensity expected in an open Universe with cold dark matter (CDM) and a nearly scale-invariant spectrum of adiabatic density perturbations. Results are presented as a function of the nonrelativistic-matter density Ω0\Omega_0 (in units of the critical density) and the x-ray bias bxb_x (evaluated at a redshift z≃1z\simeq1 in evolving-bias models) for both an open Universe and a flat cosmological-constant Universe. Recent experimental upper limits to the amplitude of this cross-correlation provide a new constraint to the Ω0\Omega_0-bxb_x parameter space that open-CDM models (and the open-inflation models that produce them) must satisfy.Comment: 4 pages, LaTeX. Revised version contains additional figure that clarifies new constraint. (To appear in PRL.
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