39 research outputs found

    Coagulation by Random Velocity Fields as a Kramers Problem

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    We analyse the motion of a system of particles suspended in a fluid which has a random velocity field. There are coagulating and non-coagulating phases. We show that the phase transition is related to a Kramers problem, and use this to determine the phase diagram, as a function of the dimensionless inertia of the particles, epsilon, and a measure of the relative intensities of potential and solenoidal components of the velocity field, Gamma. We find that the phase line is described by a function which is non-analytic at epsilon=0, and which is related to escape over a barrier in the Kramers problem. We discuss the physical realisations of this phase transition.Comment: 4 pages, 3 figure

    Caustics in turbulent aerosols

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    Networks of caustics can occur in the distribution of particles suspended in a randomly moving gas. These can facilitate coagulation of particles by bringing them into close proximity, even in cases where the trajectories do not coalesce. We show that the long-time morphology of these caustic patterns is determined by the Lyapunov exponents lambda_1, lambda_2 of the suspended particles, as well as the rate J at which particles encounter caustics. We develop a theory determining the quantities J, lambda_1, lambda_2 from the statistical properties of the gas flow, in the limit of short correlation times.Comment: 4 pages, 3 figure

    "If we use the strength of diversity among researchers we can only improve the quality and impact of our research": Issues of equality, diversity, inclusion, and transparency in the process of applying for research funding

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    This paper sets out the recommendations that have emerged from a six-month-long exploration and discussion of the processes that take place before research is submitted for funding: the ‘pre-award’ environment. Our work concentrated on how this environment is experienced by researchers at all career stages and from a variety of backgrounds, demographics, and disciplines, as well as by research managers and research support professionals. In the later stages of our exploration, representatives from research funders were also involved in the discussions. The primary component of this project was an analysis of pre-award activities and processes at UK universities, using information collated from workshops with researchers and research management and support staff. The findings of this analysis were presented as a workflow diagram, which was then used to surface issues relating to equality, diversity, inclusion, and transparency in context. The workflow diagram and the issues highlighted by it were used to structure discussions at a symposium for a range of research stakeholders, held in Bristol, UK, in January 2023. The recommendations set out in this paper are drawn from discussions that took place at that event. This paper is not an exhaustive landscape analysis, nor a review of existing research and practice in the area of pre-award processes or of recent thinking on the topics of equality, diversity, and inclusion (EDI). Instead, it aims to summarise and encapsulate the suggestions put forward by the stakeholders during the symposium. These recommendations, from experienced professionals working in the field, are based on their encounters with the issues raised in the project. They do not solely relate to those working on pre-award processes, but may also apply to funders, policymakers, university leaders, and professional associations, since many of the challenges flagged in our research are systemic and cultural, and reach far beyond the research office

    Communicable Diseases Prioritized for Surveillance and Epidemiological Research: Results of a Standardized Prioritization Procedure in Germany, 2011

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    To establish strategic priorities for the German national public health institute (RKI) and guide the institute's mid-term strategic decisions, we prioritized infectious pathogens in accordance with their importance for national surveillance and epidemiological research.We used the Delphi process with internal (RKI) and external experts and a metric-consensus approach to score pathogens according to ten three-tiered criteria. Additional experts were invited to weight each criterion, leading to the calculation of a median weight by which each score was multiplied. We ranked the pathogens according to the total weighted score and divided them into four priority groups.., Respiratory syncytial virus or Hantavirus) indicate a possible under-recognised importance within the current German public health framework. A process to strengthen respective surveillance systems and research has been started. The prioritization methodology has worked well; its modular structure makes it potentially useful for other settings

    A checklist for health research priority setting: nine common themes of good practice

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    Health research priority setting processes assist researchers and policymakers in effectively targeting research that has the greatest potential public health benefit. Many different approaches to health research prioritization exist, but there is no agreement on what might constitute best practice. Moreover, because of the many different contexts for which priorities can be set, attempting to produce one best practice is in fact not appropriate, as the optimal approach varies per exercise. Therefore, following a literature review and an analysis of health research priority setting exercises that were organized or coordinated by the World Health Organization since 2005, we propose a checklist for health research priority setting that allows for informed choices on different approaches and outlines nine common themes of good practice. It is intended to provide generic assistance for planning health research prioritization processes. The checklist explains what needs to be clarified in order to establish the context for which priorities are set; it reviews available approaches to health research priority setting; it offers discussions on stakeholder participation and information gathering; it sets out options for use of criteria and different methods for deciding upon priorities; and it emphasizes the importance of well-planned implementation, evaluation and transparency

    An observational cohort study to produce and evaluate an improved tool to screen older women with back pain for osteoporotic vertebral fractures (Vfrac): study protocol.

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    The aim of this study is to produce an easy to use checklist for general practitioners to complete whenever a woman aged over 65 years with back pain seeks healthcare. This checklist will produce a binary output to determine if the patient should have a radiograph to diagnose vertebral fracture. PURPOSE: People with osteoporotic vertebral fractures are important to be identified as they are at relatively high risk of further fractures. Despite this, less than a third of people with osteoporotic vertebral fractures come to clinical attention due to various reasons including lack of clear triggers to identify who should have diagnostic spinal radiographs. This study aims to produce and evaluate a novel screening tool (Vfrac) for use in older women presenting with back pain in primary care based on clinical triggers and predictors identified previously. This tool will generate a binary output to determine if a radiograph is required. METHODS: The Vfrac study is a two-site, pragmatic, observational cohort study recruiting 1633 women aged over 65 years with self-reported back pain. Participants will be recruited from primary care in two sites. The Vfrac study will use data from two self-completed questionnaires, a simple physical examination, a lateral thoracic and lateral lumbar radiograph and information contained in medical records. RESULTS: The primary objective is to develop an easy-to-use clinical screening tool for identifying older women who are likely to have vertebral fractures. CONCLUSIONS: This article describes the protocol of the Vfrac study; ISRCTN16550671

    Evaluating the use of citizens' juries in food policy: a case study of food regulation

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    BACKGROUND Deliberative engagement techniques and citizens’ juries are touted as means of incorporating the public into policy decision-making, managing community expectations and increasing commitment to public health policy. This paper reports a study to examine the feasibility of citizens’ juries as a means of collecting data to inform public health policy related to food regulation through evaluation of the conduct of a citizens’ jury. METHODS A citizens’ jury was conducted with a representative sample of 17 South Australians to explore their willingness to consider the proposition that food and drink advertising and/or sponsorship should be banned at children’s sporting events. RESULTS The results showed that, in relation to the central proposition and evaluation data from the jury, opinion on the proposition remained comparatively stable. Most jurors indicated that they thought that food and drink sponsorship and/or advertising at children’s sporting events would have little or no effect on altering children’s diet and eating habits, with the proportion increasing during the jury process. Jurors were given evaluation sheets about the content of the jury and the process of the citizens’ jury to complete at the end of the session. The evaluation of the citizens’ jury process revealed positive perceptions. The majority of jurors agreed that their knowledge of the issues of food and drink sponsorship in children’s sport had increased as a result of participation in the citizens’ jury. The majority also viewed the decision-making process as fair and felt that their views were listened to. One important response in the evaluation was that all jurors indicated that, if given the opportunity, they would participate in another citizens’ jury. CONCLUSIONS The findings suggest that the citizens’ jury increased participant knowledge of the issue and facilitated reflective discussion of the proposition. Citizens’ juries are an effective means of gaining insight into public views of policy and the circumstances under which the public will consider food regulation; however a number of issues need to be considered to ensure the successful conduct of a citizens’ jury.Julie Henderson, Elizabeth House, John Coveney, Samantha Meyer, Rachel Ankeny, Paul Ward and Michael Calna
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