2,562 research outputs found

    Probing interactions in mesoscopic gold wires

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    We have measured in gold wires the energy exchange rate between quasiparticles, the phase coherence time of quasiparticles and the resistance vs. temperature, in order to probe the interaction processes which are relevant at low temperatures. We find that the energy exchange rate is higher than expected from the theory of electron-electron interactions, and that it has a different energy dependence. The dephasing time is constant at temperatures between 8 K and 0.5 K, and it increases below 0.5 K. The magnetoresistance is negative at large field scales, and the resistance decreases logarithmically with increasing temperatures, indicating the presence of magnetic impurities, probably Fe. Whereas resistivity and phase coherence measurements can be attributed to magnetic impurities, the question is raised whether these magnetic impurities could also mediate energy exchanges between quasiparticles.Comment: latex pothier.tex, 12 files, 15 pages in: Proceedings of the NATO Advanced Research Workshop on Size Dependent Magnetic Scattering, Pesc, Hungary, May 28 - June 1st, 2000 Chandrasekhar V., Van Haesendonck C. eds (Kluwer, 2001) [SPEC-S00/083

    Ideal cardiovascular health and risk of cardiovascular events in the EPIC-Norfolk prospective population study.

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    BACKGROUND: The American Heart Association has prioritised seven cardiovascular health metrics to reduce the cardiovascular burden, including: body mass index, healthy diet, physical activity, smoking status, blood pressure, glycated haemoglobin A1c and total cholesterol. The aim of the current study was to assess the association between the American Heart Association-defined health metrics and the risk of cardiovascular events in the EPIC-Norfolk prospective study. DESIGN: Prospective cohort study. METHODS: An overall cardiovascular health score was calculated based on the number of health metrics including ideal, intermediate or poor. Cox proportional hazards models were used to describe the association of the seven metrics separately and the overall health score with risk of coronary heart disease, stroke and cardiovascular disease. A total of 10,043 participants was included in the analysis (follow-up 1993-2008). For all individual health metrics a more ideal status was associated with a lower risk of cardiovascular events. RESULTS AND CONCLUSION: As for the overall cardiovascular health score, those in the highest (i.e. healthiest) category (score 12-14) had an adjusted hazard ratio for coronary heart disease of 0.07 (95% confidence interval (CI) 0.02-0.29, P < 0.001), for stroke of 0.16 (95% CI 0.02-1.37, P = 0.09) and for cardiovascular disease of 0.07 (95% CI 0.02-0.23, P < 0.001), compared to people in the lowest (i.e. unhealthiest) category (score 0-2). The overall cardiovascular health score was strongly and inversely associated with risk of coronary heart disease, stroke and cardiovascular disease. Our data suggest that even small improvements in modifiable risk factors may lead to substantial reductions in the risks of cardiovascular events.The EPIC-Norfolk Study is funded by Cancer Research UK grant number 14136 and the Medical Research Council grant number G1000143, SL is supported by a studentship from Unilever Corporate Research, UK.This is the author accepted manuscript. The final version is available from SAGE via http://dx.doi.org/10.1177/204748731560201

    Policy Coherence in US Tobacco Control: Beyond FDA Regulation

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    Joshua Yang and Thomas Novotny explore whether the US government can develop and implement a coherent policy agenda to reduce tobacco-related morbidity and mortality

    Physical activity as a treatment for depression: the TREAD randomised trial protocol

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    Published version. Copyright © 2010 BioMed CentralBackground: Depression is one of the most common reasons for consulting a General Practitioner (GP) within the UK. Whilst antidepressants have been shown to be clinically effective, many patients and healthcare professionals would like to access other forms of treatment as an alternative or adjunct to drug therapy for depression. A recent systematic review presented some evidence that physical activity could offer one such option, although further investigation is needed to test its effectiveness within the context of the National Health Service. The aim of this paper is to describe the protocol for a randomised, controlled trial (RCT) designed to evaluate an intervention developed to increase physical activity as a treatment for depression within primary care. Methods/design: The TREAD study is a pragmatic, multi-centre, two-arm RCT which targets patients presenting with a new episode of depression. Patients were approached if they were aged 18-69, had recently consulted their GP for depression and, where appropriate, had been taking antidepressants for less than one month. Only those patients with a confirmed diagnosis of a depressive episode as assessed by the Clinical Interview Schedule-Revised (CIS-R), a Beck Depression Inventory (BDI) score of at least 14 and informed written consent were included in the study. Eligible patients were individually randomised to one of two treatment groups; usual GP care or usual GP care plus facilitated physical activity. The primary outcome of the trial is clinical symptoms of depression assessed using the BDI four months after randomisation. A number of secondary outcomes are also measured at the 4-, 8- and 12-month follow-up points including quality of life, attitude to and involvement in physical activity and antidepressant use/adherence. Outcomes will be analysed on an intention-to-treat (ITT) basis and will use linear and logistic regression models to compare treatments. Discussion: The results of the trial will provide information about the effectiveness of physical activity as a treatment for depression. Given the current prevalence of depression and its associated economic burden, it is hoped that TREAD will provide a timely contribution to the evidence on treatment options for patients, clinicians and policy-makers

    Survey of the quality of experimental design, statistical analysis and reporting of research using animals

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    For scientific, ethical and economic reasons, experiments involving animals should be appropriately designed, correctly analysed and transparently reported. This increases the scientific validity of the results, and maximises the knowledge gained from each experiment. A minimum amount of relevant information must be included in scientific publications to ensure that the methods and results of a study can be reviewed, analysed and repeated. Omitting essential information can raise scientific and ethical concerns. We report the findings of a systematic survey of reporting, experimental design and statistical analysis in published biomedical research using laboratory animals. Medline and EMBASE were searched for studies reporting research on live rats, mice and non-human primates carried out in UK and US publicly funded research establishments. Detailed information was collected from 271 publications, about the objective or hypothesis of the study, the number, sex, age and/or weight of animals used, and experimental and statistical methods. Only 59% of the studies stated the hypothesis or objective of the study and the number and characteristics of the animals used. Appropriate and efficient experimental design is a critical component of high-quality science. Most of the papers surveyed did not use randomisation (87%) or blinding (86%), to reduce bias in animal selection and outcome assessment. Only 70% of the publications that used statistical methods described their methods and presented the results with a measure of error or variability. This survey has identified a number of issues that need to be addressed in order to improve experimental design and reporting in publications describing research using animals. Scientific publication is a powerful and important source of information; the authors of scientific publications therefore have a responsibility to describe their methods and results comprehensively, accurately and transparently, and peer reviewers and journal editors share the responsibility to ensure that published studies fulfil these criteria

    Feasibility of school students Skyping care home residents to reduce loneliness

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    Background Intergenerational friendship has proved useful for older people in increasing socialisation. We explored the feasibility of school students Skyping older people in care homes with the long-term aim of reducing loneliness. Methods Six school students from one secondary school and twenty older people, including seven with mild to moderate dementia, from three care homes, engaged in Skype video-calls over six weeks. A conversational aid aimed to help school students maintain conversations was employed. Students and care staff completed feedback forms after each session on video-call usage, usefulness of the conversational aid, and barriers and benefits of video-calls. Six care staff provided further feedback on residents’ experiences through unstructured interviews. Interviews and field notes were thematically analysed. Results Residents enjoyed Skype-calls with school students. Over six weeks, video-calls became longer, and more residents participated. Analysis revealed four themes. First, the intervention led to increased mobility for three older people and improved self-care in regard to personal appearance for five residents. Second, school students and older people formed friendships which inspired the need to meet in person. Third, the use of video-calls enabled participants to view each other’s environments in real time. Last, directly experiencing the intervention was important for the continued participation of the care staff in the study. Skype-calls between schools and care homes are feasible and may help reduce loneliness. Conclusions Institutional collaboration between educational settings and care homes through cost effective video-calls can be useful to increase socialisation for older people, and promote later on-going use with other external organisations to help reduce loneliness and social isolation

    Evaluation of Morphological Plasticity in the Cerebella of Basketball Players with MRI

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    Cerebellum is a key structure involved in motor learning and coordination. In animal models, motor skill learning increased the volume of molecular layer and the number of synapses on Purkinje cells in the cerebellar cortex. The aim of this study is to investigate whether the analogous change of cerebellar volume occurs in human population who learn specialized motor skills and practice them intensively for a long time. Magnetic resonance image (MRI)-based cerebellar volumetry was performed in basketball players and matched controls with V-works image software. Total brain volume, absolute and relative cerebellar volumes were compared between two groups. There was no significant group difference in the total brain volume, the absolute and the relative cerebellar volume. Thus we could not detect structural change in the cerebellum of this athlete group in the macroscopic level
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