3,118 research outputs found

    History and development of validation with the ESP-r simulation program

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    It is well recognised that validation of dynamic building simulation programs is a long-term complex task. There have been many large national and international efforts that have led to a well-established validation methodology comprising analytical, inter-program comparison and empirical validation elements, and a significant number of tests have been developed. As simulation usage increases, driven by such initiatives as the European Energy Performance of Buildings Directive, such tests are starting to be incorporated into national and international standards. Although many program developers have run many of the developed tests, there does not appear to have been a systematic attempt to incorporate such tests into routine operation of the simulation programs. This paper reports work undertaken to address this deficiency. The paper summarizes the tests that have been applied to the simulation program ESP-r. These tests have been developed within International Energy Agency Annexes, within CEN standards, within various large-scale national projects, and by the UK's Chartered Institution of Building Services Engineers. The structure used to encapsulate the tests allows developers to ensure that recent code modifications have not resulted in unforeseen impacts on program predictions, and allows users to check for themselves against benchmarks

    The role of soil factors and leaf protein in the utilization of mopane plants by elephants in northern Botswana

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    BACKGROUND: Mopane (Colophospermum mopane) plants form monotypic woodlands that cover extensive areas in northern Botswana. Mopane is also a principal food item in the diet of elephants. Obtrusive damage to mopane plants as a result of elephant feeding may alter the structure of mopane woodlands. Some mopane woodland areas in northern Botswana are subjected to heavy elephant utilization rates whereas other mopane areas are less affected. However, the underlying reason for the concentrated elephant utilization is unknown. RESULTS: Ten mopane plots were subjected to sampling of soil properties that included structure, pH, nitrogen, phosphorus, potassium contents and protein contents. Elevated nitrogen and phosphorus contents in soils correlated with high protein levels in mopane leaves. Protein levels in leaves of mopane plants differed significantly between sites. However, multivariate analyses of environmental parameters and plots suggested that on a regional scale, there was no difference in the extent of elephant damage to mopane plants due to differential protein levels in leaves or any of the underlying soi factors that were examined. CONCLUSIONS: From management perspective, this pattern mitigates the likelihood that an even more prolific elephant population will alter mopane woodland habitats irreversibly

    The Effect of Privately Provided Police Services on Crime

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    Research demonstrates that police reduce crime. The implication of this research for investment in a particular form of extra police services, those provided by private institutions, has not been rigorously examined. We capitalize on the discontinuity in police force size at the geographic boundary of a private university police department to estimate the effect of the extra police services on crime. Extra police provided by the university generate approximately 45-60 percent fewer crimes in the surrounding neighborhood. These effects appear to be similar to other estimates in the literature
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