862 research outputs found

    Monitoring sediment transfer processes on the desert margin

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    LANDSAT Thematic Mapper and Multispectral Scanner data have been used to construct change detection images for three playas in south-central Tunisia. Change detection images have been used to analyze changes in surface reflectance and absorption between wet and dry season (intra-annual change) and between different years (inter-annual change). Change detection imagery has been used to examine geomorphological changes on the playas. Changes in geomorphological phenomena are interpreted from changes in soil and foliar moisture levels, differences in reflectances between different salt and sediments and the spatial expression of geomorphological features. Intra-annual change phenomena that can be detected from multidate imagery are changes in surface moisture, texture and chemical composition, vegetation cover and the extent of aeolian activity. Inter-annual change phenomena are divisible into those restricted to marginal playa facies (sedimentation from sheetwash and alluvial fans, erosion from surface runoff and cliff retreat) and these are found in central playa facies which are related to the internal redistribution of water, salt and sediment

    Towards agent-based crowd simulation in airports using games technology

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    We adapt popular video games technology for an agent-based crowd simulation in an airport terminal. To achieve this, we investigate the unique traits of airports and implement a virtual crowd by exploiting a scalable layered intelligence technique in combination with physics middleware and a socialforces approach. Our experiments show that the framework runs at interactive frame-rate and evaluate the scalability with increasing number of agents demonstrating navigation behaviour

    Imaging interactions between the immune and cardiovascular systems in vivo by multiphoton microscopy

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    Several recent studies in immunology have used multiphoton laser-scanning microscopy to visualise the induction of an immune response in real time in vivo. These experiments are illuminating the cellular and molecular interactions involved in the induction, maintenance and regulation of immune responses. Similar approaches are being applied in cardiovascular research where there is an increasing body of evidence to support a significant role for the adaptive immune system in vascular disease. As such, we have begun to dissect the role of T lymphocytes in atherosclerosis in real time in vivo. Here, we provide step-by-step guides to the various stages involved in visualising the migration of T cells within a lymph node and their infiltration into inflamed tissues such as atherosclerotic arteries. These methods provide an insight into the mechanisms involved in the activation and function of immune cells in vivo

    Modelling ecosystem adaptation and dangerous rates of global warming

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    This is the author accepted manuscript. The final version is available from Portland Press via the DOI in this recordWe are in a period of relatively rapid climate change. This poses challenges for individual species and threatens the ecosystem services that humanity relies upon. Temperature is a key stressor. In a warming climate, individual organisms may be able to shift their thermal optima through phenotypic plasticity. However, such plasticity is unlikely to be sufficient over the coming centuries. Resilience to warming will also depend on how fast the distribution of traits that define a species can adapt through other methods, in particular through redistribution of the abundance of variants within the population and through genetic evolution. In this paper, we use a simple theoretical ‘trait diffusion’ model to explore how the resilience of a given species to climate change depends on the initial trait diversity (biodiversity), the trait diffusion rate (mutation rate), and the lifetime of the organism. We estimate theoretical dangerous rates of continuous global warming that would exceed the ability of a species to adapt through trait diffusion, and therefore lead to a collapse in the overall productivity of the species. As the rate of adaptation through intraspecies competition and genetic evolution decreases with species lifetime, we find critical rates of change that also depend fundamentally on lifetime. Dangerous rates of warming vary from 1°C per lifetime (at low trait diffusion rate) to 8°C per lifetime (at high trait diffusion rate). We conclude that rapid climate change is liable to favour short-lived organisms (e.g. microbes) rather than longer-lived organisms (e.g. trees).University of ExeterCSSP-Brazi

    The perception and management of risk in UK office property development

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    Risk is an ever-present aspect of business, and risk taking is necessary for profit and economic progress. Speculative property development is popularly perceived as a 'risky business' yet, like other entrepreneurs, developers have opportunities to manage the risks they face; techniques include phasing and joint ventures. The associated areas of investment portfolio risk, development risk analysis and construction risk management have all been addressed by research. This article presents new knowledge about how developers perceive risks and the means they subsequently adopt to manage them. The developers of office projects across the UK were sent questionnaires by post. Respondents were asked about their perceptions of risks at the first appraisal stage and currently and about the risk management techniques that they had adopted. In-depth interviews with a selection of respondents were then used to discuss and augment the findings. Developers were most concerned about market-based risks at both stages. Concern about production-orientated risks was lower and fell significantly between the two stages. A fixed price contract was the most common risk management technique. Risk management techniques were used more often outside London and the South East. Developer type affects both the perception and management of risk. While developers do manage risk, decisions are made on the basis of professional and business experience. These findings should help development companies manage risk in a more objective and analytical way

    How primary care can contribute to good mental health in adults.

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    The need for support for good mental health is enormous. General support for good mental health is needed for 100% of the population, and at all stages of life, from early childhood to end of life. Focused support is needed for the 17.6% of adults who have a mental disorder at any time, including those who also have a mental health problem amongst the 30% who report having a long-term condition of some kind. All sectors of society and all parts of the NHS need to play their part. Primary care cannot do this on its own. This paper describes how primary care practitioners can help stimulate such a grand alliance for health, by operating at four different levels - as individual practitioners, as organisations, as geographic clusters of organisations and as policy-makers
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