718 research outputs found

    Development of a radioimmunoassay to measure luteinizing hormone in bovine blood

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    A radioimmunoassay using tubes coated with antibody was developed to measure luteinizing hormone (LH) in bovine blood. Antisera to bovine LH (NIH-LH-B7) were raised in rabbits. Non-specificity of pooled antisera was removed from the antisera by adsorption. The reliability of the assay for use in physiological studies is described

    SSR assessment of Phytophthora infestans populations on tomato and potato in British gardens demonstrates high diversity but no evidence for host specialisation

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    Phytophthora infestans populations can differ in composition as a result of host-specialisation on tomato and potato hosts. In Great Britain many amateur gardeners grow outdoor tomatoes but there is little or no commercial tomato production outdoors. This study analysed isolates of P. infestans from British gardens with twelve multiplexed SSR markers that are used to monitor the disease on commercial potato crops. Samples of P. infestans from tomato hosts were collected in three years and from potato in one year from across Great Britain. Seven previously unreported genotypes were detected in garden populations and higher frequencies of unique clonal lineages (28% to 40%) were present compared with populations from British commercial potato crops reported elsewhere. Garden populations had a lower proportion (11% to 48% less) of the most common lineages (13_A2 and 6_A1) which together made up at least 86% of the commercial potato populations during the sampling period. Host species accounted for only 2.6% of molecular variance detected between garden potato- and tomato-hosted samples. No significant difference in clonal lineage composition was found between host species in Great Britain and this could be due to the whole P. infestans population over-wintering on potato. British garden populations on both hosts were much more diverse than those on commercial potato crops; this finding may be influenced by less frequent fungicide use by gardeners and a higher diversity of un-sprayed susceptible potato cultivars enabling metalaxyl-sensitive and less virulent genotypes to survive in gardens

    Light and Life: Exotic Photosynthesis in Binary Star Systems

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    The potential for hosting photosynthetic life on Earth-like planets within binary/multiple stellar systems was evaluated by modelling the levels of photosynthetically active radiation (PAR) such planets receive. Combinations of M and G stars in: (i) close-binary systems; (ii) wide-binary systems and (iii) three-star systems were investigated and a range of stable radiation environments found to be possible. These environmental conditions allow for the possibility of familiar, but also more exotic forms of photosynthetic life, such as infrared photosynthesisers and organisms specialised for specific spectral niches.Comment: Accepted for publication in: Astrobiolog

    An evaluation of shoe tread parameters using FEM

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    Within this paper, a three-dimensional finite element (FE) model of a uniformly loaded, single rubber block, is described and run using loading conditions replicative of a standard slip resistant footwear test. The FE model considers rubber hyperelastic and viscoelastic material properties, obtained using dynamic mechanical analysis. The performance of the FE model was evaluated through analytical compression analysis and experimental contact area testing. The effect of tread grooves was investigated with relation to slip-resistance during walking. Analysis and discussion are provided of the tread model's sliding contact areas, contact pressure, stress, and front edge mechanics

    On Pole Assignment and Stabilizability of Neutral Type Systems

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    In this note we present a systematic approach to the stabilizability problem of linear infinite-dimensional dynamical systems whose infinitesimal generator has an infinite number of instable eigenvalues. We are interested in strong non-exponential stabilizability by a linear feed-back control. The study is based on our recent results on the Riesz basis property and a careful selection of the control laws which preserve this property. The investigation may be applied to wave equations and neutral type delay equations

    Perceptions of 'coming out' among British Muslim gay men

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    The cultural processes of heteronormativity and compulsory heterosexuality are acutely active within Islamic societies. The present study explored perceptions of 'coming out' among a group of British Muslim gay men (BMGM), focussing upon the potential consequences for identity processes and psychological well-being. Ten BMGM of Pakistani descent were interviewed using a semi-structured interview schedule. Interview transcripts were subjected to interpretative phenomenological analysis and informed by identity process theory. Four superordinate themes are reported, including (1) 'social representational constraints upon "coming out"'; (2) ' "coming out": a source of shame and a threat to distinctiveness'; (3) 'fear of physical violence from ingroup members'; and (4) 'foreseeing the future: "coming out" as a coping strategy'. Data suggest that BMGM face a bi-dimensional homophobia from ethno-religious ingroup members and the general population, which can render the prospect of 'coming out' threatening for identity. Theoretical and practical implications of this research are discussed
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