565 research outputs found

    Habitat Utilization and Seasonal Movements of Black Bears in the Great Smoky Mountains National Park

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    A radiotelemetry study to determine seasonal movements and habitat utilization of black bears (Ursus americanus) in the Great Smoky Mountains National Park was undertaken from June 1980 to May 1982. Annual home range size in a year of poor hard mast production was 119 km2 and 13 km2 for males and females, respectively, and 36 km2 and 6 km2 in a year of good hard mast production. Bear movements were governed by seasonal food availability. Bears exhibited an affinity to summer home ranges but traveled to widely dispersed fall ranges. Seasonal range shifts were more evident in years of poor hard mast than good hard mast. Eleven of 14 radiocollared bears traveled extensively in fall 1980, a poor mast year. Three of 6 females and every one of 8 males traveled to various parts of North Carolina; bears spent time in the Park, the Cherokee National Forest, the Nantahala National Forest, and private lands adjoining these federal lands. Three males were killed illegally, 1 was hunter-harvested, and the 7 other bears returned to the study area from fall 1980 ranges. Only 1 bear traveled widely in fall 1981, and no radiocollared bears were killed. Bears used different forest cover types non-randomly during different seasons. Oak forests are extremely important to bear survival in the Southern Appalachians. Abundant spring fruits, summer berries, and fall hard mast make the oak types critical habitat for bears. Bears regularly crossed roads and trails according to their spatial arrangement in their home ranges. Limiting road access into bear range is important to bear survival

    Assessment of crystallographic orientation effects on secondary ion mass spectrometry (SIMS) analysis of cassiterite

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    Crystallographic orientation effects on ion microprobe analyses for U-Pb and O-isotopes have been reported for a number of oxide minerals, including rutile (TiO₂) and baddeleyite (ZrO₂). Here we evaluate the effects of crystal orientation on U-Pb and O-isotopic data measured by ion microprobe on cassiterite (SnO₂), which is isostructural with rutile. The crystallographic orientations of mounted and polished grains of cassiterite were determined by electron backscatter diffraction (EBSD). Those grains were then analysed for U-Th-Pb isotopes and ¹⁸O/¹⁶O compositions using the SHRIMP RG and SHRIMP SI ion microprobes, respectively. Based on these data, cassiterite appears to show no dependence of key measurement parameters such as UO₂/UO, Pb/UO, or ¹⁸O/¹⁶O ratios at the achieved precision with crystallographic orientation. The contrasting behaviour of isostructural cassiterite and rutile provides new insights into the mechanisms leading to crystallographic orientation effects during ion microprobe analyses with electronic structure proposed as being a significant factor

    Associations between attentional bias and interpretation bias and change in school concerns and anxiety symptoms during the transition from primary to secondary school

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    The transition from primary to secondary school is often associated with a period of heightened anxiety and worry. For most children, any feelings of anxiety subside relatively quickly but for a small minority, emotional difficulties can continue into the first year of secondary school and beyond. This study recruited 109 children and measured their anxiety symptoms and school concerns toward the end of primary school and again at the end of their first term of secondary school. We investigated for the first time whether pre-transition measures of attentional and interpretation bias, and the magnitude of change in attentional bias toward and away from threat stimuli were associated with pre- and post-transition measures of anxiety and school concerns, and the change in these measures over time. Over 50% of the current sample exceeded clinical levels of anxiety at pre-transition. However, anxiety symptoms and school concerns had significantly reduced by post-transition. Higher levels of pre-transition anxiety or school concerns, and a greater magnitude of change in attentional bias towards threat stimuli predicted a larger reduction in anxiety symptoms and school concerns across the transition period. A greater interpretation bias toward threat was associated with higher pre-transition anxiety symptoms and school concerns but not post-transition scores, or the change in these scores. While many children experience heightened anxiety prior to school transition, this appears to be largely temporary and self-resolves. Nonetheless, the current findings highlight the importance of monitoring children’s anxiety and concerns, and related cognitive processes during this important transition period

    Micronutrients and respiratory infections: the biological rationale and current state of clinical evaluation

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    A range of nutrients has been studied or proposed for use in preventing respiratory tract infections and reducing their severity. This article gives a narrative review of the existing literature, biological rationales and current state of clinical evaluation for micronutrient therapies. The importance of vitamin A, the B vitamins, vitamin C, vitamin D, eicosapentaenoic acid, vitamin E, selenium, zinc and a range of combination therapies are discussed, looking at their effects on reducing rates of infection, reducing severity of infection and improved recovery from infection. Further discussion regarding the level of evidence required for nutritional interventions is included

    Challenging the 'New Professionalism': from managerialism to pedagogy?

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    In recent years there have been changes made to the conceptualisation of continuing professional development for teachers in both the Scottish and English systems of education. These changes have been instigated by successive UK governments (and more recently, by the Scottish Executive), together with the General teaching Council for Scotland (GTCS) and the General Teaching Council for England (GTCE). This paper argues that these changes have not provided a clear rationale for CPD, but instead have introduced tensions between the concept of teacher education and that of training. The need for a less confused understanding of CPD and its purposes is underlined, as is the need for school based approaches to continuing teacher education. Arguably, teacher education must move from technicist emphases to a model which integrates the social processes of change within society and schools with the individual development and empowerment of teachers

    Reconstituted B cell receptor signaling reveals carbohydrate-dependent mode of activation

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    Activation of immune cells (but not B cells) with lectins is widely known. We used the structurally defined interaction between influenza hemagglutinin (HA) and its cell surface receptor sialic acid (SA) to identify a B cell receptor (BCR) activation modality that proceeded through non-cognate interactions with antigen. Using a new approach to reconstitute antigen-receptor interactions in a human reporter B cell line, we found that sequence-defined BCRs from the human germline repertoire could be triggered by both complementarity to influenza HA and a separate mode of signaling that relied on multivalent ligation of BCR sialyl-oligosaccharide. The latter suggested a new mechanism for priming naïve B cell responses and manifested as the induction of SA-dependent pan-activation by peripheral blood B cells. BCR crosslinking in the absence of complementarity is a superantigen effect induced by some microbial products to subvert production of antigen-specific immune responses. B cell superantigen activity through affinity for BCR carbohydrate is discussed

    Baryogenesis from Primordial Blackholes after Electroweak Phase Transition

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    Incorporating a realistic model for accretion of ultra-relativistic particles by primordial blackholes (PBHs), we study the evolution of an Einstein-de Sitter universe consisting of PBHs embedded in a thermal bath from the epoch 1033\sim 10^{-33} sec to 5×109\sim 5\times 10^{-9} sec. In this paper we use Barrow et al's ansatz to model blackhole evaporation in which the modified Hawking temperature goes to zero in the limit of the blackhole attaining a relic state with mass mpl\sim m_{pl}. Both single mass PBH case as well as the case in which blackhole masses are distributed in the range 8×1023×1058\times 10^2 - 3\times 10^5 gm have been considered in our analysis. Blackholes with mass larger than 105\sim 10^5 gm appear to survive beyond the electroweak phase transition and, therefore, successfully manage to create baryon excess via XXˉX-\bar X emissions, averting the baryon number wash-out due to sphalerons. In this scenario, we find that the contribution to the baryon-to-entropy ratio by PBHs of initial mass mm is given by ϵζ(m/1gm)1\sim \epsilon \zeta (m/1 {gm})^{-1}, where ϵ\epsilon and ζ\zeta are the CP-violating parameter and the initial mass fraction of the PBHs, respectively. For ϵ\epsilon larger than 104\sim 10^{-4}, the observed matter-antimatter asymmetry in the universe can be attributed to the evaporation of PBHs.Comment: Latex2e file with seven figures included as postscript file

    High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data II: The Spring Equatorial Stripe

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    This is the second paper in a series aimed at finding high-redshift quasars from five-color (u'g'r'i'z') imaging data taken along the Celestial Equator by the Sloan Digital Sky Survey (SDSS) during its commissioning phase. In this paper, we present 22 high-redshift quasars (z>3.6) discovered from ~250 deg^2 of data in the spring Equatorial Stripe, plus photometry for two previously known high-redshift quasars in the same region of sky. Our success rate of identifying high-redshift quasars is 68%. Five of the newly discovered quasars have redshifts higher than 4.6 (z=4.62, 4.69, 4.70, 4.92 and 5.03). All the quasars have i* < 20.2 with absolute magnitude -28.8 < M_B < -26.1 (h=0.5, q_0=0.5). Several of the quasars show unusual emission and absorption features in their spectra, including an object at z=4.62 without detectable emission lines, and a Broad Absorption Line (BAL) quasar at z=4.92.Comment: 28 pages, AJ in press (Jan 2000), final version with minor changes; high resolution finding charts available at http://www.astro.princeton.edu/~fan/paper/qso2.htm
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