24,210 research outputs found
The metabolism of ingested peroxides Final report, 1 May 1970 - 30 Apr. 1971
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
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
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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New and emerging technologies for the treatment of inherited retinal diseases: a horizon scanning review.
The horizon scanning review aimed to identify new and emerging technologies in development that have the potential to slow or stop disease progression and/or reverse sight loss in people with inherited retinal diseases (IRDs). Potential treatments were identified using recognized horizon scanning methods. These included a combination of online searches using predetermined search terms, suggestions from clinical experts and patient and carer focus groups, and contact with commercial developers. Twenty-nine relevant technologies were identified. These included 9 gene therapeutic approaches, 10 medical devices, 5 pharmacological agents, and 5 regenerative and cell therapies. A further 11 technologies were identified in very early phases of development (typically phase I or pre-clinical) and were included in the final report to give a complete picture of developments 'on the horizon'. Clinical experts and patient and carer focus groups provided helpful information and insights, such as the availability of specialised services for patients, the potential impacts of individual technologies on people with IRDs and their families, and helped to identify additional relevant technologies. This engagement ensured that important areas of innovation were not missed. Most of the health technologies identified are still at an early stage of development and it is difficult to estimate when treatments might be available. Further, well designed trials that generate data on efficacy, applicability, acceptability, and costs of the technologies, as well as the long-term impacts for various conditions are required before these can be considered for adoption into routine clinical practice
Supercurrent coupling in the Faddeev-Skyrme model
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
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
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