80 research outputs found

    Classification of time series by shapelet transformation

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    Time-series classification (TSC) problems present a specific challenge for classification algorithms: how to measure similarity between series. A \emph{shapelet} is a time-series subsequence that allows for TSC based on local, phase-independent similarity in shape. Shapelet-based classification uses the similarity between a shapelet and a series as a discriminatory feature. One benefit of the shapelet approach is that shapelets are comprehensible, and can offer insight into the problem domain. The original shapelet-based classifier embeds the shapelet-discovery algorithm in a decision tree, and uses information gain to assess the quality of candidates, finding a new shapelet at each node of the tree through an enumerative search. Subsequent research has focused mainly on techniques to speed up the search. We examine how best to use the shapelet primitive to construct classifiers. We propose a single-scan shapelet algorithm that finds the best kk shapelets, which are used to produce a transformed dataset, where each of the kk features represent the distance between a time series and a shapelet. The primary advantages over the embedded approach are that the transformed data can be used in conjunction with any classifier, and that there is no recursive search for shapelets. We demonstrate that the transformed data, in conjunction with more complex classifiers, gives greater accuracy than the embedded shapelet tree. We also evaluate three similarity measures that produce equivalent results to information gain in less time. Finally, we show that by conducting post-transform clustering of shapelets, we can enhance the interpretability of the transformed data. We conduct our experiments on 29 datasets: 17 from the UCR repository, and 12 we provide ourselve

    Stereotactically guided breast biopsy: a review

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    The aims of this review are to compare and contrast the available stereotactic equipment, and to describe the variety of needle types used and their affect on pathological results and subsequent patient management. Initial stereotactic devices were “added-on” to analogue mammography units and have been replaced by prone or ducubitus equipment using digital image acquisition. Biopsies use either 14-G core biopsy (CB) needles or vacuum-assisted biopsies (VAB). Vacuum-assisted biopsy systems consistently out-perform 14-G CB with reduced need for diagnostic or multi-treatment surgery. The false-negative rate is 8% for 14-G CB compared with 0.7% for VAB. There is a risk of underestimating the disease present for lesions of uncertain malignant potential (Cat B3) and suspicious of malignancy (Cat B4) results with 25% of patients with a B3 biopsy found to have cancer at subsequent surgery and 66% of those with a B4 biopsy. A CB diagnosis of in situ malignancy is upgraded to invasive disease at surgery in 15-36% of patients undergoing CB and of the order of 10% with VAB. A high degree of diagnostic accuracy and hence safe patient care can only be achieved by meticulous attention to technique and multi-disciplinary cooperation

    The great time series classification bake off: a review and experimental evaluation of recent algorithmic advances

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    In the last five years there have been a large number of new time series classification algorithms proposed in the literature. These algorithms have been evaluated on subsets of the 47 data sets in the University of California, Riverside time series classification archive. The archive has recently been expanded to 85 data sets, over half of which have been donated by researchers at the University of East Anglia. Aspects of previous evaluations have made comparisons between algorithms difficult. For example, several different programming languages have been used, experiments involved a single train/test split and some used normalised data whilst others did not. The relaunch of the archive provides a timely opportunity to thoroughly evaluate algorithms on a larger number of datasets. We have implemented 18 recently proposed algorithms in a common Java framework and compared them against two standard benchmark classifiers (and each other) by performing 100 resampling experiments on each of the 85 datasets. We use these results to test several hypotheses relating to whether the algorithms are significantly more accurate than the benchmarks and each other. Our results indicate that only 9 of these algorithms are significantly more accurate than both benchmarks and that one classifier, the Collective of Transformation Ensembles, is significantly more accurate than all of the others. All of our experiments and results are reproducible: we release all of our code, results and experimental details and we hope these experiments form the basis for more rigorous testing of new algorithms in the future

    The clock gene <i>Bmal1</i> inhibits macrophage motility, phagocytosis, and impairs defense against pneumonia

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    The circadian clock regulates many aspects of immunity. Bacterial infections are affected by time of day, but the mechanisms involved remain undefined. Here we show that loss of the core clock protein BMAL1 in macrophages confers protection against pneumococcal pneumonia. Infected mice show both reduced weight loss and lower bacterial burden in circulating blood. In vivo studies of macrophage phagocytosis reveal increased bacterial ingestion following Bmal1 deletion, which was also seen in vitro. BMAL1−/− macrophages exhibited marked differences in actin cytoskeletal organization, a phosphoproteome enriched for cytoskeletal changes, with reduced phosphocofilin and increased active RhoA. Further analysis of the BMAL1−/− macrophages identified altered cell morphology and increased motility. Mechanistically, BMAL1 regulated a network of cell movement genes, 148 of which were within 100 kb of high-confidence BMAL1 binding sites. Links to RhoA function were identified, with 29 genes impacting RhoA expression or activation. RhoA inhibition restored the phagocytic phenotype to that seen in control macrophages. In summary, we identify a surprising gain of antibacterial function due to loss of BMAL1 in macrophages, associated with a RhoA-dependent cytoskeletal change, an increase in cell motility, and gain of phagocytic function

    A systematic review of the effectiveness and cost-effectiveness of peer education and peer support in prisons.

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    BACKGROUND: Prisoners experience significantly worse health than the general population. This review examines the effectiveness and cost-effectiveness of peer interventions in prison settings. METHODS: A mixed methods systematic review of effectiveness and cost-effectiveness studies, including qualitative and quantitative synthesis was conducted. In addition to grey literature identified and searches of websites, nineteen electronic databases were searched from 1985 to 2012. Study selection criteria were: Population: Prisoners resident in adult prisons and children resident in Young Offender Institutions (YOIs). INTERVENTION: Peer-based interventions Comparators: Review questions 3 and 4 compared peer and professionally led approaches. OUTCOMES: Prisoner health or determinants of health; organisational/ process outcomes; views of prison populations. STUDY DESIGNS: Quantitative, qualitative and mixed method evaluations. RESULTS: Fifty-seven studies were included in the effectiveness review and one study in the cost-effectiveness review; most were of poor methodological quality. Evidence suggested that peer education interventions are effective at reducing risky behaviours, and that peer support services are acceptable within the prison environment and have a positive effect on recipients, practically or emotionally. Consistent evidence from many, predominantly qualitative, studies, suggested that being a peer deliverer was associated with positive effects. There was little evidence on cost-effectiveness of peer-based interventions. CONCLUSIONS: There is consistent evidence from a large number of studies that being a peer worker is associated with positive health; peer support services are also an acceptable source of help within the prison environment and can have a positive effect on recipients. Research into cost-effectiveness is sparse. SYSTEMATIC REVIEW REGISTRATION: PROSPERO ref: CRD42012002349

    The circadian clock protein REVERBα inhibits pulmonary fibrosis development

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    Pulmonary inflammatory responses lie under circadian control; however, the importance of circadian mechanisms in the underlying fibrotic phenotype is not understood. Here, we identify a striking change to these mechanisms resulting in a gain of amplitude and lack of synchrony within pulmonary fibrotic tissue. These changes result from an infiltration of mesenchymal cells, an important cell type in the pathogenesis of pulmonary fibrosis. Mutation of the core clock protein REVERBα in these cells exacerbated the development of bleomycin-induced fibrosis, whereas mutation of REVERBα in club or myeloid cells had no effect on the bleomycin phenotype. Knockdown of REVERBα revealed regulation of the little-understood transcription factor TBPL1. Both REVERBα and TBPL1 altered integrinβ1 focal-adhesion formation, resulting in increased myofibroblast activation. The translational importance of our findings was established through analysis of 2 human cohorts. In the UK Biobank, circadian strain markers (sleep length, chronotype, and shift work) are associated with pulmonary fibrosis, making them risk factors. In a separate cohort, REVERBα expression was increased in human idiopathic pulmonary fibrosis (IPF) lung tissue. Pharmacological targeting of REVERBα inhibited myofibroblast activation in IPF fibroblasts and collagen secretion in organotypic cultures from IPF patients, thus suggesting that targeting of REVERBα could be a viable therapeutic approach

    A qualitative synthesis of the positive and negative impacts related to delivery of peer-based health interventions in prison settings

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    Background Peer interventions involving prisoners in delivering peer education and peer support in a prison setting can address health need and add capacity for health services operating in this setting. This paper reports on a qualitative synthesis conducted as part of a systematic review of prison-based peer interventions. One of the review questions aimed to investigate the positive and negative impacts of delivering peer interventions within prison settings. This covered organisational and process issues relating to peer interventions, including prisoner and staff views. Methods A qualitative synthesis of qualitative and mixed method studies was undertaken. The overall study design comprised a systematic review involving searching, study selection, data extraction and validity assessment. Studies reporting interventions with prisoners or ex-prisoners delivering education or support to prisoners resident in any type of prison or young offender institution, all ages, male and female, were included. A thematic synthesis was undertaken with a subset of studies reporting qualitative data (n=33). This involved free coding of text reporting qualitative findings to develop a set of codes, which were then grouped into thematic categories and mapped back to the review question. Results Themes on process issues and wider impacts were grouped into four thematic categories: peer recruitment training and support; organisational support; prisoner relationships; prison life. There was consistent qualitative evidence on the need for organisational support within the prison to ensure smooth implementation and on managing security risks when prisoners were involved in service delivery. A suite of factors affecting the delivery of peer interventions and the wider organisation of prison life were identified. Alongside reported benefits of peer delivery, some reasons for non-utilisation of services by other prisoners were found. There was weak qualitative evidence on wider impacts on the prison system, including better communication between staff and prisoners. Gaps in evidence were identified. Conclusions The quality of included studies limited the strength of the conclusions. The main conclusion is that peer interventions cannot be seen as independent of prison life and health services need to work in partnership with prison services to deliver peer interventions. More research is needed on long-term impacts

    Utility of Post-Mortem Genetic Testing in Cases of Sudden Arrhythmic Death Syndrome.

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    BACKGROUND: Sudden arrhythmic death syndrome (SADS) describes a sudden death with negative autopsy and toxicological analysis. Cardiac genetic disease is a likely etiology. OBJECTIVES: This study investigated the clinical utility and combined yield of post-mortem genetic testing (molecular autopsy) in cases of SADS and comprehensive clinical evaluation of surviving relatives. METHODS: We evaluated 302 expertly validated SADS cases with suitable DNA (median age: 24 years; 65% males) who underwent next-generation sequencing using an extended panel of 77 primary electrical disorder and cardiomyopathy genes. Pathogenic and likely pathogenic variants were classified using American College of Medical Genetics (ACMG) consensus guidelines. The yield of combined molecular autopsy and clinical evaluation in 82 surviving families was evaluated. A gene-level rare variant association analysis was conducted in SADS cases versus controls. RESULTS: A clinically actionable pathogenic or likely pathogenic variant was identified in 40 of 302 cases (13%). The main etiologies established were catecholaminergic polymorphic ventricular tachycardia and long QT syndrome (17 [6%] and 11 [4%], respectively). Gene-based rare variants association analysis showed enrichment of rare predicted deleterious variants in RYR2 (p = 5 × 10(-5)). Combining molecular autopsy with clinical evaluation in surviving families increased diagnostic yield from 26% to 39%. CONCLUSIONS: Molecular autopsy for electrical disorder and cardiomyopathy genes, using ACMG guidelines for variant classification, identified a modest but realistic yield in SADS. Our data highlighted the predominant role of catecholaminergic polymorphic ventricular tachycardia and long QT syndrome, especially the RYR2 gene, as well as the minimal yield from other genes. Furthermore, we showed the enhanced utility of combined clinical and genetic evaluation

    Primary Schoolchildren’s Experiences of Participatory Theatre in a Heritage Site

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    There is a growing need for articulation of the theoretical framework underpinning performance as a learning medium in heritage sites and for an in-depth insight into the children's experiences therein. The aim of this paper is to explore some of the themes that emerged from researching participatory theatre in a historic house as experienced by two primary school groups. The methodology drawing upon the principles of participatory research with children and a constructivist theoretical framework employed interviews, observations and drawings as data generation methods to explore the children's individual and collective experiences. The research findings underline the interplay between the events' theatrical and interpretive format and advocate the significance of children's co-authorship of such events

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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