24,210 research outputs found

    The metabolism of ingested peroxides Final report, 1 May 1970 - 30 Apr. 1971

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    Determination of growth patterns in rats fed on balanced diets differing by the presence of either oxidized or unoxidized fa

    Pedestrian demand modelling of large cities: an applied example from London

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    This paper introduces a methodology for the development of city wide pedestrian demand models and shows its application to London. The approach used for modelling is Multiple Regression Analysis of independent variables against the dependent variable of observed pedestrian flows. The test samples were from manual observation studies of average total pedestrian flow per hour on 237 sample sites. The model will provide predicted flow values for all 7,526 street segments in the 25 square kilometres of Central London. It has been independently validated by Transport for London and is being tested against further observation data. The longer term aim is to extend the model to the entire greater London area and to incorporate additional policy levers for use as a transport planning and evaluation tool

    Exploring knowledge exchange: a useful framework for practice and policy

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    Knowledge translation is underpinned by a dynamic and social knowledge exchange process but there are few descriptions of how this unfolds in practice settings. This has hampered attempts to produce realistic and useful models to help policymakers and researchers understand how knowledge exchange works. This paper reports the results of research which investigated the nature of knowledge exchange. We aimed to understand whether dynamic and fluid definitions of knowledge exchange are valid and to produce a realistic, descriptive framework of knowledge exchange. Our research was informed by a realist approach. We embedded a knowledge broker within three service delivery teams across a large mental health organisation, each of whom was grappling with specific challenges. The knowledge broker participated in the team's problem-solving process and collected observational fieldnotes. We also interviewed the team members. Observational and interview data were analysed quantitatively and qualitatively in order to determine and describe the nature of the knowledge exchange process in more detail. This enabled us to refine our conceptual framework of knowledge exchange. We found that knowledge exchange can be understood as a dynamic and fluid process which incorporates distinct forms of knowledge from multiple sources. Quantitative analysis illustrated that five broadly-defined components of knowledge exchange (problem, context, knowledge, activities, use) can all be in play at any one time and do not occur in a set order. Qualitative analysis revealed a number of distinct themes which better described the nature of knowledge exchange. By shedding light on the nature of knowledge exchange, our findings problematise some of the linear, technicist approaches to knowledge translation. The revised model of knowledge exchange which we propose here could therefore help to reorient thinking about knowledge exchange and act as a starting point for further exploration and evaluation of the knowledge exchange process

    Metabolic Disposition of Phenylbutazone and Oxyphenbutazone in the horse

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    Supercurrent coupling in the Faddeev-Skyrme model

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    Motivated by the sigma model limit of multicomponent Ginzburg-Landau theory, a version of the Faddeev-Skyrme model is considered in which the scalar field is coupled dynamically to a one-form field called the supercurrent. This coupled model is investigated in the general setting where physical space is an oriented Riemannian manifold and the target space is a Kaehler manifold. It is shown that supercurrent coupling destroys the topological stability enjoyed by the usual Faddeev-Skyrme model, so that there can be no globally stable knot solitons in this model. Nonetheless, local energy minimizers may still exist. The first variation formula is derived and used to construct three families of static solutions of the model, all on compact domains. In particular, a coupled version of the unit-charge hopfion on a three-sphere of arbitrary radius is found. The second variation formula is derived, and used to analyze the stability of some of these solutions. A family of stable solutions is identified, though these may exist only in spaces of even dimension. Finally, it is shown that, in contrast to the uncoupled model, the coupled unit hopfion on the three-sphere of radius R is unstable for all R. This gives an explicit, exact example of supercurrent coupling destabilizing a stable solution of the uncoupled Faddeev-Skyrme model, and casts doubt on the conjecture of Babaev, Faddeev and Niemi that knot solitons should exist in the low-energy regime of two-component superconductors.Comment: 17 page

    A mathematical modelling study of an athlete's sprint time when towing a weighted sled

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s12283-013-0114-2.This study used a mathematical model to examine the effects of the sled, the running surface, and the athlete on sprint time when towing a weighted sled. Simulations showed that ratio scaling is an appropriate method of normalising the weight of the sled for athletes of different body size. The relationship between sprint time and the weight of the sled was almost linear, as long as the sled was not excessively heavy. The athlete’s sprint time and rate of increase in sprint time were greater on running surfaces with a greater coefficient of friction, and on any given running surface an athlete with a greater power-to-weight ratio had a lower rate of increase in sprint time. The angle of the tow cord did not have a substantial effect on an athlete’s sprint time. This greater understanding should help coaches set the training intensity experienced by an athlete when performing a sled-towing exercise

    Physical Evidence in the Investigation of Traffic Accidents

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