12,786 research outputs found

    1,25(OH)2 vitamin D3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine

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    Intestinal absorption of phosphate is stimulated by 1,25(OH)2 vitamin D3. At least two distinct mechanisms underlie phosphate absorption in the gut, an active transcellular transport requiring the Na+/phosphate cotransporter NaPi‐IIb/Slc34a2, and a poorly characterized paracellular passive pathway. 1,25(OH)2 vitamin D3 stimulates NaPi‐IIb expression and function, and loss of NaPi‐IIb reduces intestinal phosphate absorption. However, it is remains unknown whether NaPi‐IIb is the only target for hormonal regulation by 1,25(OH)2 vitamin D3. Here we compared the effects of intraperitoneal administration of 1,25(OH)2 vitamin D3 (2 days, once per day) in wild‐type and intestinal‐specific Slc34a2‐deficient mice, and analysed trans‐ vs. paracellular routes of phosphate absorption. We found that treatment stimulated active transport of phosphate only in jejunum of wild‐type mice, though NaPi‐IIb protein expression was upregulated in jejunum and ileum. In contrast, 1,25(OH)2 vitamin D3 administration had no effect in Slc34a2‐deficient mice, suggesting that the hormone specifically regulates NaPi‐IIb expression. In both groups, 1,25(OH)2 vitamin D3 elicited the expected increase of plasma fibroblast growth factor 23 (FGF23) and reduction of parathyroid hormone (PTH). Treatment resulted in hyperphosphaturia (and hypercalciuria) in both genotypes, though mice remained normophosphataemic. While increased intestinal absorption and higher FGF23 can trigger the hyperphosphaturic response in wild types, only higher FGF23 can explain the renal response in Slc34a2‐deficient mice. Thus, 1,25(OH)2 vitamin D3 stimulates intestinal phosphate absorption by acting on the active transcellular pathway mostly mediated by NaPi‐IIb while the paracellular pathway appears not to be affected

    Geobase Information System Impacts on Space Image Formats

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    As Geobase Information Systems increase in number, size and complexity, the format compatability of satellite remote sensing data becomes increasingly more important. Because of the vast and continually increasing quantity of data available from remote sensing systems the utility of these data is increasingly dependent on the degree to which their formats facilitate, or hinder, their incorporation into Geobase Information Systems. To merge satellite data into a geobase system requires that they both have a compatible geographic referencing system. Greater acceptance of satellite data by the user community will be facilitated if the data are in a form which most readily corresponds to existing geobase data structures. The conference addressed a number of specific topics and made recommendations

    Developing an On-Line Interactive Health Psychology Module.

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    On-line teaching material in health psychology was developed which ensured a range of students could access appropriate material for their course and level of study. This material has been developed around the concept of smaller 'content chunks' which can be combined into whole units of learning (topics), and ultimately, a module. On the basis of the underlying philosophy that the medium is part of the message, we considered interactivity to be a key element in engaging the student with the material. Consequently, the key aim of this development was to stimulate and engage students, promoting better involvement with the academic material, and hence better learning. It was hoped that this was achieved through the development of material including linked programmes and supporting material, small Java Scripts and basic email, forms and HTML additions. This material is outlined as are some of the interactive activities introduced, and the preliminary student and tutor experience described

    Vegetation and Topographic Control of Wind-blown Snow Distributions in Distributed and Aggregated Simulations for an Arctic Tundra Basin

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    In the Pacific Northwest (PNW), concern about the impacts of climate and land cover change on water resources and flood-generating processes emphasizes the need for a mechanistic understanding of the interactions between forest canopies and hydrologic processes. Detailed measurements during the 1999 and 2000 hydrologic years were used to modify the Simultaneous Heat and Water (SHAW) model for application in forested systems. Major changes to the model include improved representation of rainfall interception and stomatal conductance dynamics. The model was developed for the 1999 hydrologic year and tested for the 2000 hydrologic year without modification of the site parameters. The model effectively simulated throughfall, soil water content profiles, and shallow soil temperatures for both years. The largest discrepancies between soil moisture and temperature were observed during periods of discontinuous snow cover due to spatial variability that was not explicitly simulated by the model. Soil warming at bare locations was delayed until most of the snow cover ablated because of the large heat sink associated with the residual snow patches. During the summer, simulated transpiration decreased from a maximum monthly mean of 2.2 mm day⁻Âč in July to 1.3 mm day⁻Âč in September as a result of decreasing soil moisture and declining net radiation. The results indicate that a relatively simple representation of the vegetation canopy can accurately simulate seasonal hydrologic fluxes in this environment, except during periods of discontinuous snow cover

    Preparing potential teachers for the transition from employment to teacher training: an evaluative case study of a Maths Enhancement Course

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    In response to a UK government drive to improve maths teaching in schools, the South West London Maths Enhancement Course (MEC) has been set up though collaboration between three Higher Education institutions (HEIs) to provide an efficient route for non maths graduates in employment to upgrade their subject knowledge and give a smooth transition into teacher training (PGCE). An evaluation of the scheme, measured against Teacher Development Agency (TDA) objectives and success criteria agreed by university staff, involved thematic analysis of focus group discussions and interviews with students and staff during both the MEC and PGCE courses. This has revealed a high level of satisfaction and success related to a number of underlying issues, particularly around student recruitment, curriculum design, peer support and staff collaboration. The model offers an example of practice transferable to a range of programmes aimed at supporting students in the transition between levels and institutions

    The holy blood and the holy grail: Myths of scientific racism and the pursuit of excellence in sport

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    Despite the continuing publication of research that suggests there is no scientific basis to 'race' as a biological category, theories of racial difference continue to be invoked within sport to explain the perceived dominance of black athletes. In the case of John Entine's controversial 'Taboo: why black athletes dominate sports and why we are afraid to talk about it' or undergraduate textbooks that suggest 'racial differences' in physique may significantly affect athletic performance, scientific racism is normalised in sport. In this article, the relationship between scientific racism and sport will be examined. Qualitative research with current sport scientists is used to investigate the socio-ethical tensions within the subject field of sport science between professionalism, scientism and the demand from external interests to produce results that help people in sport win medals. It will be shown that these tensions, combined with the history of race as a category in sport science, combine to create the discourse of scientific knowledge that reflects, rather than challenges, folk genetics of black athletic physicality

    Academic freedom in Europe: reviewing UNESCO’s recommendation

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    This paper examines the compliance of universities in the European Union with the UNESCO Recommendation concerning the Status of Higher–Education Teaching Personnel, which deals primarily with protection for academic freedom. The paper briefly surveys the European genesis of the modern research university and academic freedom, before evaluating compliance with the UNESCO recommendation on institutional autonomy, academic freedom, university governance and tenure. Following from this, the paper examines the reasons for the generally low level of compliance with the UNESCO Recommendation within the EU states, and considers how such compliance could be improved
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