763 research outputs found

    Quantum Fermion Hair

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    It is shown that the Dirac operator in the background of a magnetic %Reissner-Nordstr\"om black hole and a Euclidean vortex possesses normalizable zero modes in theories containing superconducting cosmic strings. One consequence of these zero modes is the presence of a fermion condensate around magnetically charged black holes which violates global quantum numbers.Comment: 16pp (harvmac (l)) and 2 figs.(not included

    Erythrocyte acid phosphatase phenotype and gestational length: no relationship in a sample of 3001 births

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    Erythrocyte acid phosphatase (ACP1) phenotype was examined in 3001 Caucasian infants born at the University of Michigan Women's Hospital. Contrary to reports from other studies, there was no relationship between the ACP1 phenotype and risk of preterm birth in either the total sample or when the sample was subdivided by sex of infant.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27696/1/0000082.pd

    Black Holes with a Massive Dilaton

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    The modifications of dilaton black holes which result when the dilaton acquires a mass are investigated. We derive some general constraints on the number of horizons of the black hole and argue that if the product of the black hole charge QQ and the dilaton mass mm satisfies Qm<O(1)Q m < O(1) then the black hole has only one horizon. We also argue that for Qm>O(1)Q m > O(1) there may exist solutions with three horizons and we discuss the causal structure of such solutions. We also investigate the possible structures of extremal solutions and the related problem of two-dimensional dilaton gravity with a massive dilaton.Comment: 36 pages with 5 figures (as uuencoded compressed tar file) (revised version has one major change in bound on mass for extremal solution and minor typos fixed), harvma

    A guide to evaluating linkage quality for the analysis of linked data.

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    Linked datasets are an important resource for epidemiological and clinical studies, but linkage error can lead to biased results. For data security reasons, linkage of personal identifiers is often performed by a third party, making it difficult for researchers to assess the quality of the linked dataset in the context of specific research questions. This is compounded by a lack of guidance on how to determine the potential impact of linkage error. We describe how linkage quality can be evaluated and provide widely applicable guidance for both data providers and researchers. Using an illustrative example of a linked dataset of maternal and baby hospital records, we demonstrate three approaches for evaluating linkage quality: applying the linkage algorithm to a subset of gold standard data to quantify linkage error; comparing characteristics of linked and unlinked data to identify potential sources of bias; and evaluating the sensitivity of results to changes in the linkage procedure. These approaches can inform our understanding of the potential impact of linkage error and provide an opportunity to select the most appropriate linkage procedure for a specific analysis. Evaluating linkage quality in this way will improve the quality and transparency of epidemiological and clinical research using linked data

    Family satisfaction with critical care in the UK: a multicentre cohort study.

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    OBJECTIVE: To assess family satisfaction with intensive care units (ICUs) in the UK using the Family Satisfaction in the Intensive Care Unit 24-item (FS-ICU-24) questionnaire, and to investigate how characteristics of patients and their family members impact on family satisfaction. DESIGN: Prospective cohort study nested within a national clinical audit database. SETTING: Stratified, random sample of 20 adult general ICUs participating in the Intensive Care National Audit & Research Centre Case Mix Programme. PARTICIPANTS: Family members of patients staying at least 24 hours in ICU were recruited between May 2013 and June 2014. INTERVENTIONS: Consenting family members were sent a postal questionnaire 3 weeks after the patient died or was discharged from ICU. Up to four family members were recruited per patient. MAIN OUTCOME MEASURES: Family satisfaction was measured using the FS-ICU-24 questionnaire. MAIN RESULTS: A total of 12 346 family members of 6380 patients were recruited and 7173 (58%) family members of 4615 patients returned a completed questionnaire. Overall and domain-specific family satisfaction scores were high (mean overall family satisfaction 80, satisfaction with care 83, satisfaction with information 76 and satisfaction with decision-making 73 out of 100) but varied significantly across adult general ICUs studied and by whether the patient survived ICU. For family members of ICU survivors, characteristics of both the family member (age, ethnicity, relationship to patient (next-of-kin and/or lived with patient) and visit frequency) and the patient (acute severity of illness and receipt of invasive mechanical ventilation) were significant determinants of family satisfaction, whereas, for family members of ICU non-survivors, only patient characteristics (age, acute severity of illness and duration of stay) were significant. CONCLUSIONS: Overall family satisfaction in UK adult general ICUs was high but varied significantly. Adjustment for differences in family member/patient characteristics is important to avoid falsely identifying ICUs as statistical outliers. TRIAL REGISTRATION NUMBER: ISRCTN47363549

    Characterisation of COPD heterogeneity in the ECLIPSE cohort

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    Background Chronic obstructive pulmonary disease (COPD) is a complex condition with pulmonary and extra-pulmonary manifestations. This study describes the heterogeneity of COPD in a large and well characterised and controlled COPD cohort (ECLIPSE). Methods We studied 2164 clinically stable COPD patients, 337 smokers with normal lung function and 245 never smokers. In these individuals, we measured clinical parameters, nutritional status, spirometry, exercise tolerance, and amount of emphysema by computed tomography. Results COPD patients were slightly older than controls and had more pack years of smoking than smokers with normal lung function. Co-morbidities were more prevalent in COPD patients than in controls, and occurred to the same extent irrespective of the GOLD stage. The severity of airflow limitation in COPD patients was poorly related to the degree of breathlessness, health status, presence of co-morbidity, exercise capacity and number of exacerbations reported in the year before the study. The distribution of these variables within each GOLD stage was wide. Even in subjects with severe airflow obstruction, a substantial proportion did not report symptoms, exacerbations or exercise limitation. The amount of emphysema increased with GOLD severity. The prevalence of bronchiectasis was low (4%) but also increased with GOLD stage. Some gender differences were also identified. Conclusions The clinical manifestations of COPD are highly variable and the degree of airflow limitation does not capture the heterogeneity of the disease

    The NIHR collaboration for leadership in applied health research and care (CLAHRC) for greater manchester: combining empirical, theoretical and experiential evidence to design and evaluate a large-scale implementation strategy

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    Background: In response to policy recommendations, nine National Institute for Health Research (NIHR) Collaborations for Leadership in Applied Health Research and Care (CLAHRCs) were established in England in 2008, aiming to create closer working between the health service and higher education and narrow the gap between research and its implementation in practice. The Greater Manchester (GM) CLAHRC is a partnership between the University of Manchester and twenty National Health Service (NHS) trusts, with a five-year mission to improve healthcare and reduce health inequalities for people with cardiovascular conditions. This paper outlines the GM CLAHRC approach to designing and evaluating a large-scale, evidence- and theory-informed, context-sensitive implementation programme. Discussion: The paper makes a case for embedding evaluation within the design of the implementation strategy. Empirical, theoretical, and experiential evidence relating to implementation science and methods has been synthesised to formulate eight core principles of the GM CLAHRC implementation strategy, recognising the multi-faceted nature of evidence, the complexity of the implementation process, and the corresponding need to apply approaches that are situationally relevant, responsive, flexible, and collaborative. In turn, these core principles inform the selection of four interrelated building blocks upon which the GM CLAHRC approach to implementation is founded. These determine the organizational processes, structures, and roles utilised by specific GM CLAHRC implementation projects, as well as the approach to researching implementation, and comprise: the Promoting Action on Research Implementation in Health Services (PARIHS) framework; a modified version of the Model for Improvement; multiprofessional teams with designated roles to lead, facilitate, and support the implementation process; and embedded evaluation and learning. Summary: Designing and evaluating a large-scale implementation strategy that can cope with and respond to the local complexities of implementing research evidence into practice is itself complex and challenging. We present an argument for adopting an integrative, co-production approach to planning and evaluating the implementation of research into practice, drawing on an eclectic range of evidence sources.Gill Harvey, Louise Fitzgerald, Sandra Fielden, Anne McBride, Heather Waterman, David Bamford, Roman Kislo and Ruth Boade
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