758 research outputs found

    Statistical sensitivity for detection of spatial and temporal patterns in rodent population densities.

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    A long-term monitoring program begun 1 year after the epidemic of hantavirus pulmonary syndrome in the U.S. Southwest tracked rodent density changes through time and among sites and related these changes to hantavirus infection rates in various small-mammal reservoir species and human disease outbreaks. We assessed the statistical sensitivity of the program's field design and tested for potential biases in population estimates due to unintended deaths of rodents. Analyzing data from two sites in New Mexico from 1994 to 1998, we found that for many species of Peromyscus, Reithrodontomys, Neotoma, Dipodomys, and Perognathus, the monitoring program detected species-specific spatial and temporal differences in rodent densities; trap-related deaths did not significantly affect long-term population estimates. The program also detected a short-term increase in rodent densities in the winter of 1997-98, demonstrating its usefulness in identifying conditions conducive to increased risk for human disease

    Institutional engagement of internationalization of higher education in Kazakhstan

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    Applying theories of internationalization, organization structures, and policy transfer, this research examined institutional engagement with internationalization by higher education institutions in Kazakhstan, and generated insights into the alignment and disjunction of strategies and approaches at the national and institutional levels, as well as the progress and challenges faced by Kazakhstani higher education institutions

    LGBTQ+ Emerging Adults Perceptions of Discrimination and Exclusion within the LGBTQ+ Community

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    Research on LGBTQ+ emerging adult populations has primarily focused on discrimination that is experienced within the heterodominant culture. Due to systems of oppression and the forces of power and privilege, some sexual and gender minorities experience isolation and discrimination not only within the heterodominant culture, but within the LGBTQ+ community as well. Fourteen lesbian, gay, bisexual, transgender, or queer/questioning (LGBTQ+) young adults (20-25 years) with a diverse array of intersecting identities (e.g., gender, racial, ethnic, religious, cultural) participated in semi-structured individual interviews and focus groups. Participants reported on experiences of biphobia, acephobia, transphobia, gatekeeping the community, LGBTQ+ people of colour’s experiences of racism within the community, other forms of oppression, and offered advice on areas of growth for the LGBTQ+ community. Findings provide insight into LGBTQ+ emerging adults experiences of discrimination and future research implications

    Dynamics of vortex penetration, jumpwise instabilities and nonlinear surface resistance of type-II superconductors in strong rf fields

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    We consider nonlinear dynamics of a single vortex in a superconductor in a strong rf magnetic field B0sinωtB_0\sin\omega t. Using the London theory, we calculate the dissipated power Q(B0,ω)Q(B_0,\omega), and the transient time scales of vortex motion for the linear Bardeen-Stephen viscous drag force, which results in unphysically high vortex velocities during vortex penetration through the oscillating surface barrier. It is shown that penetration of a single vortex through the ac surface barrier always involves penetration of an antivortex and the subsequent annihilation of the vortex antivortex pairs. Using the nonlinear Larkin-Ovchinnikov (LO) viscous drag force at higher vortex velocities v(t)v(t) results in a jump-wise vortex penetration through the surface barrier and a significant increase of the dissipated power. We calculate the effect of dissipation on nonlinear vortex viscosity η(v)\eta(v) and the rf vortex dynamics and show that it can also result in the LO-type behavior, instabilities, and thermal localization of penetrating vortex channels. We propose a thermal feedback model of η(v)\eta(v), which not only results in the LO dependence of η(v)\eta(v) for a steady-state motion, but also takes into account retardation of temperature field around rapidly accelerating vortex, and a long-range interaction with the surface. We also address the effect of pinning on the nonlinear rf vortex dynamics and the effect of trapped magnetic flux on the surface resistance RsR_s calculated as a function or rf frequency and field. It is shown that trapped flux can result in a temperature-independent residual resistance RiR_i at low TT, and a hysteretic low-field dependence of Ri(B0)R_i(B_0), which can {\it decrease} as B0B_0 is increased, reaching a minimum at B0B_0 much smaller than the thermodynamic critical field BcB_c.Comment: 18 figure

    Preliminary evidence that low ankle-brachial index is associated with reduced bilateral hip extensor strength and functional mobility in peripheral arterial disease

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    ObjectivePeripheral arterial disease (PAD) has been associated with skeletal muscle pathology, including atrophy of the affected muscles. In addition, oxidative metabolism is impaired, muscle function is reduced, and gait and mobility are restricted. We hypothesized that greater severity of symptomatic PAD would be associated with lower levels of muscle mass, strength, and endurance, and that these musculoskeletal abnormalities in turn would impair functional performance and walking ability in patients with PAD.MethodsWe assessed 22 persons with intermittent claudication from PAD in this cross-sectional pilot study. Outcome assessments included initial claudication distance and absolute claudication distance via treadmill protocols and outcomes from the 6-minute walk (6MW). Secondary outcomes included one repetition maximum strength/endurance testing of hip extensors, hip abductors, quadriceps, hamstrings, plantar flexors, pectoral, and upper back muscle groups, as well as performance-based tests of function. Univariate and stepwise multiple regression models were constructed to evaluate relationships and are presented.ResultsTwenty-two participants (63.6% male; mean [standard deviation] age, 73.6 [8.2] years; range, 55-85 years) were studied. Mean (standard deviation) resting ankle-brachial index (ABI) was 0.54 ([0.13]; range, 0.28-0.82), and participants ranged from having mild claudication to rest pain. Lower resting ABI was significantly associated with reduced bilateral hip extensor strength (r = 0.54; P = .007) and reduced whole body strength (r = 0.32; P = .05). In addition, lower ABI was associated with a shorter distance to first stop during the 6MW (r = 0.38; P = .05) and poorer single leg balance (r = 0.44; P = .03). Reduced bilateral hip extensor strength was also significantly associated with functional outcomes, including reduced 6MW distance to first stop (r = 0.74; P = .001), reduced 6MW distance (r = 0.75; P < .001), and reduced total short physical performance battery score (worse function; r = 0.75; P = .003).ConclusionsOur results suggest the existence of a causal pathway from a reduction in ABI to muscle atrophy and weakness, to whole body disability represented by claudication outcomes and performance-based tests of functional mobility in an older cohort with symptomatic PAD. Longitudinal outcomes from this study and future trials are required to investigate the effects of an anabolic intervention targeting the muscles involved in mobility and activities of daily living and whether an increase in muscle strength will improve symptoms of claudication and lead to improvements in other functional outcomes in patients with PAD

    Effect of a Fundamental Motor Skills Intervention on Fundamental Motor Skill and Physical Activity in a Preschool Setting: A Cluster Randomized Controlled Trial

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    Purpose: To determine the effect of a 12-week fundamental motor skill (FMS) program on FMS and physical activity (PA) on preschool-aged children. Method: A cluster randomized controlled trial. The intervention (PhysicaL ActivitY and Fundamental Motor Skills in Pre-schoolers [PLAYFun] Program) was a 12-week games-based program, delivered directly to the children in childcare centers by exercise physiologists. Children in the control arm received the usual preschool curriculum. Outcomes included FMS competence (Test of Gross Motor Development-2) and PA (accelerometer) assessed at baseline, 12 weeks, and 24 weeks (12-wk postintervention). Results: Fifty children (mean age = 4.0 [0.6] y; 54% male) were recruited from 4 childcare centers. Two centers were randomized to PLAYFun and 2 centers were randomized to the waitlist control group. Children attended on average 2.0 (1.0) 40-minute sessions per week. The PLAYFun participants demonstrated significant increases in object control (P < .001) and total FMS (P = .010) competence at week 12, compared with controls in a group × time interaction. Girls, but not boys, in PLAYFun significantly increased moderate to vigorous PA after the intervention (P = .004). These increases were not maintained 12-week postcompletion of PLAYFun. Conclusions: The PLAYFun Program is effective at improving FMS competence in boys and girls and increasing PA in girls. However, improvements are not maintained when opportunities to practice are not sustained

    Parity-Affected Superconductivity in Ultrasmall Metallic Grains

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    We investigate the breakdown of BCS superconductivity in {\em ultra}\/small metallic grains as a function of particle size (characterized by the mean spacing dd between discrete electronic eigenstates), and the parity (PP = even/odd) of the number of electrons on the island. Assuming equally spaced levels, we solve the parity-dependent BCS gap equation for the order parameter ΔP(d,T)\Delta_P (d,T). Both the T=0T=0 critical level spacing dc,Pd_{c,P} and the critical temperature Tc,P(d)T_{c,P} (d) at which ΔP=0\Delta_P = 0 are parity dependent, and both are so much smaller in the odd than the even case that these differences should be measurable in current experiments.Comment: 4 pages RevTeX, 1 encapsulated postscript figure, submitted to Physical Review Letter

    Calculation of Optical Conductivity of YbB12_{12} using Realistic Tight-Binding Model

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    Based on the previously reported tight-binding model fitted to the LDA+U band calculation, optical conductivity of the prototypical Kondo insulator YbB12_{12} is calculated theoretically. Many-body effects are taken into account by the self-consistent second order perturbation theory. The gross shape of the optical conductivity observed in experiments are well described by the present calculation, including their temperature-dependences.Comment: 6 pages, 7 figures, use jpsj2.cls, to appear in J. Phys. Soc. Jpn. Vol.73, No.10 (2004

    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

    Correlation Effects on Optical Conductivity of FeSi

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    Effects of electron correlation in FeSi are studied in terms of the two-band Hubbard model with the density of states obtained from the band calculation. Using the self-consistent second-order perturbation theory combined with the local approximation, the correlation effects are investigated on the density of states and the optical conductivity spectrum, which are found to reproduce the experiments done by Damascelli et al. semiquantitatively. It is also found that the peak at the gap edge shifts to lower energy region by correlation effects, as is seen in the experiments.Comment: 4 pages, 3 figure
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