2,423 research outputs found

    U.S. stock market interaction network as learned by the Boltzmann Machine

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    We study historical dynamics of joint equilibrium distribution of stock returns in the U.S. stock market using the Boltzmann distribution model being parametrized by external fields and pairwise couplings. Within Boltzmann learning framework for statistical inference, we analyze historical behavior of the parameters inferred using exact and approximate learning algorithms. Since the model and inference methods require use of binary variables, effect of this mapping of continuous returns to the discrete domain is studied. The presented analysis shows that binarization preserves market correlation structure. Properties of distributions of external fields and couplings as well as industry sector clustering structure are studied for different historical dates and moving window sizes. We found that a heavy positive tail in the distribution of couplings is responsible for the sparse market clustering structure. We also show that discrepancies between the model parameters might be used as a precursor of financial instabilities.Comment: 15 pages, 17 figures, 1 tabl

    'A light in a very dark place' : The role of a voluntary organisation providing support for those affected by encephalitis

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    Voluntary organisations are seen as contributing to the ‘democratisation’ of health and social care. Little, however, is written about their role and this paper, by focusing on the work of The Encephalitis Society, provides insights into the challenges facing voluntary organisations as they manage twin roles as service providers and advocates, of people with neurological disorders. Two studies are presented: a review conducted by the Society, focusing on patient’s experiences of neurological services; and an external evaluation of the Society’s current provision. The first, based on a postal survey of its members affected by encephalitis (n = 339), illustrates the Society’s advocacy role. The survey provided support for the Association of British Neurologists’ recommendation for nationally agreed standards of care. The second study, a postal survey of recent contacts (n = 76) and in-depth telephone interviews (n = 22), illustrates the Society’s value role as a service provider and supports its role in helping rehabilitate affected individuals and their families. These studies provided the Society with information for policy and service development. Importantly, providing the basis of informed action and partnership with stakeholders and informing the organisation’s sense of purpose, in the changing context of welfare provision in the UK

    Statistical pairwise interaction model of stock market

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    Financial markets are a classical example of complex systems as they comprise many interacting stocks. As such, we can obtain a surprisingly good description of their structure by making the rough simplification of binary daily returns. Spin glass models have been applied and gave some valuable results but at the price of restrictive assumptions on the market dynamics or others are agent-based models with rules designed in order to recover some empirical behaviours. Here we show that the pairwise model is actually a statistically consistent model with observed first and second moments of the stocks orientation without making such restrictive assumptions. This is done with an approach based only on empirical data of price returns. Our data analysis of six major indices suggests that the actual interaction structure may be thought as an Ising model on a complex network with interaction strengths scaling as the inverse of the system size. This has potentially important implications since many properties of such a model are already known and some techniques of the spin glass theory can be straightforwardly applied. Typical behaviours, as multiple equilibria or metastable states, different characteristic time scales, spatial patterns, order-disorder, could find an explanation in this picture.Comment: 11 pages, 8 figure

    Broad ligament cystic lymphangioma: A case report

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

    Rotator cuff disorders: A survey of current (2018) Italian physiotherapy practice

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    © 2020-IOS Press and the authors. All rights reserved. BACKGROUND: Shoulder pain is a common musculoskeletal complaint and disorders of the rotator cuff (RC) are widely regarded as the most common cause. Where clinical care is required, physiotherapists play an integral role. Previous studies have reported physiotherapy practice across other countries as a means of determining current practice and understanding whether practice changes over time in response to emerging research evidence. AIM: To investigate the practice of Italian physiotherapists, in order to determine current practice for the assessment and management of RC disorders. METHODS: A cross sectional online survey. A 20-item questionnaire based on one clinical vignette was developed using Survey Monkey Software. Data were analyzed descriptively and difference in proportions between those with no specific education compared to those with a specific education (i.e. 'Master's Degree,' '1-2 days Training Course' or 'Other) were analysed using the chi-squared test. RESULTS: A total of 805 participants accessed the survey with a total of 436 completed responses (54%). Fifty-five percent of respondents were male (239/436). Seventy-one percent of respondents (309/436) reported having specific education with regards to RC disorders. The methods of diagnosing RC disorders were variable across the respondents as well as the requests for imaging (184/436, 42%), the adoption of manual therapy techniques (251/436, 58%), the duration of treatment (231/436, 53% visit the patient six times at least) and the administration of physical examination tests (175/436, 40%). Advice (279/436, 64%) and some form of exercise therapy (268/436, 62%) were the most popular choices of treatment. DISCUSSION AND CONCLUSION: This current study is the first to describe Italian physiotherapy practice for RC disorders. Italian physiotherapy practice is in line with other European countries. Italian physiotherapy practice also aligns with current recommendations with regards to minimal use of imaging and prescription of therapeutic exercise. However, there is heterogeneity across the responses particularly with regards the use of manual therapy, physical examination tests, and duration of treatment. Furthermore this study is a platform for future research to explore whether Italian physiotherapy practice changes over time

    Evaluating Lifeworld as an emancipatory methodology

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    Disability research is conducted within a highly politicised ‘hotbed’ of competing paradigms and principles. New researchers, who want to work within the social model, are soon faced with complex and challenging methodological and philosophical dilemmas. The social model advocates research agendas that are focused on the emancipation and empowerment of disabled people but, in reality, these are rarely achieved. To be successful researchers need to engage with innovative and creative methodologies and to share their experiences of these within environments that welcome challenge and debate. This paper focuses on Lifeworld and assesses its value as a tool for emancipatory research. Using examples from a study with parents, whose children were in the process of being labelled as having autism, the paper illustrates how the principles that ‘underpin’ the methodology offered a supportive framework for a novice researcher

    Reduction in PA28αÎČ activation in HD mouse brain correlates to increased mHTT aggregation in cell models

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    Huntington’s disease is an autosomal dominant heritable disorder caused by an expanded CAG trinucleotide repeat at the N-terminus of the Huntingtin (HTT) gene. Lowering the levels of soluble mutant HTT protein prior to aggregation through increased degradation by the proteasome would be a therapeutic strategy to prevent or delay the onset of disease. Native PAGE experiments in HdhQ150 mice and R6/2 mice showed that PA28αÎČ disassembles from the 20S proteasome during disease progression in the affected cortex, striatum and hippocampus but not in cerebellum and brainstem. Modulating PA28αÎČ activated proteasomes in various in vitro models showed that PA28αÎČ improved polyQ degradation, but decreased the turnover of mutant HTT. Silencing of PA28αÎČ in cells lead to an increase in mutant HTT aggregates, suggesting that PA28αÎČ is critical for overall proteostasis, but only indirectly affects mutant HTT aggregation

    Continuity and change?: Exploring reactions to a guided self-management intervention in a randomised controlled trial for IBS with reference to prior experience of managing a long term condition

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    Self-care interventions are promoted as effective strategies for improving the quality of life and health outcomes for individuals with long-term health conditions. Outcome measures used in evaluations using Randomised Controlled Trials (RCTs) are not designed to consider patients' prior management strategies and experience of illness. Yet the experience of illness literature suggests that adjusting to living with chronic illness, together with broader contextual influences, are likely to be relevant to understanding responses to self-management initiatives. Using group and individual interview data we attempt to illuminate the transposition of IBS from a condition unsatisfactorily managed by medicine to one successfully managed within the life worlds of individuals. If routine embedding of complex interventions depends on the accomplishment of integration and workability in patients' everyday lives then the design and evaluation of such interventions should view participation as part of a process of continuity as well as change. Responses to formal self-management can be extended beyond psychological and other quantitatively measured outcomes. A useful addendum to trial outcomes for self-management education is an understanding of change as being inextricably linked to people's previous attempts to, and experience of, managing long-term conditions. We suggest that the benefits of understanding the prior experience of managing illness and contact with health services include the acceptability and workability of complex interventions in patients' everyday lives
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