1,069 research outputs found

    Support Vector Machines and Generalisation in HEP

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    5 pages, 6 figures. Contribution to the proceedings of the 17th International workshop on Advanced Computing and Analysis Techniques in physics research - ACAT 2016, 18 - 22 January 2016, Valpara\'iso, ChileInternational audienceWe review the concept of support vector machines (SVMs) and discuss examples of their use. One of the benefits of SVM algorithms, compared with neural networks and decision trees is that they can be less susceptible to over fitting than those other algorithms are to over training. This issue is related to the generalisation of a multivariate algorithm (MVA); a problem that has often been overlooked in particle physics. We discuss cross validation and how this can be used to improve the generalisation of a MVA in the context of High Energy Physics analyses. The examples presented use the Toolkit for Multivariate Analysis (TMVA) based on ROOT and describe our improvements to the SVM functionality and new tools introduced for cross validation within this framework

    5-Fluorouracil-induced cardiotoxicity mimicking myocardial infarction: a case report

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    BACKGROUND: Severe cardiotoxicity is a documented, but very unusual side-effect of intravenous 5-fluorouracil therapy. The mechanism producing cardiotoxicity is poorly understood. CASE PRESENTATION: A case of 5-fluorouracil-induced cardiotoxicity, possibly due to coronary artery spasm, and mimicking acute anterolateral myocardial infarction is presented and discussed. Electrocardiographs highlighting the severity of the presentation are included in the report along with coronary angiograms demonstrating the absence of significant coronary atherosclerosis. CONCLUSION: Severe 5-fluorouracil-induced cardiotoxicity is rare, but can be severe and may mimic acute myocardial infarction, leading to diagnostic and therapeutic dilemmas. Readministration of 5-fluorouracil is not advised following an episode of cardiotoxicity

    Estimating the number of components of a multicomponent nonstationary signal using the short-term time-frequency Rényi entropy

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    This article proposes a method for estimating the local number of signals components using the short term Rényi entropy of signals in the time-frequency plane. (Additional details can be found in the comprehensive book on Time-Frequency Signal Analysis and Processing (see http://www.elsevier.com/locate/isbn/0080443354). In addition, the most recent upgrade of the original software package that calculates Time-Frequency Distributions and Instantaneous Frequency estimators can be downloaded from the web site: www.time-frequency.net. This was the first software developed in the field, and it was first released publicly in 1987 at the 1st ISSPA conference held in Brisbane, Australia, and then continuously updated).The time-frequency Rényi entropy provides a measure of complexity of a nonstationary multicomponent signal in the time-frequency plane. When the complexity of a signal corresponds to the number of its components, then this information is measured as the Rényi entropy of the time-frequency distribution (TFD) of the signal. This article presents a solution to the problem of detecting the number of components that are present in short-time interval of the signal TFD, using the short-term Rényi entropy. The method is automatic and it does not require a prior information about the signal. The algorithm is applied on both synthetic and real data, using a quadratic separable kernel TFD. The results confirm that the short-term Rényi entropy can be an effective tool for estimating the local number of components present in the signal. The key aspect of selecting a suitable TFD is also discussed

    Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in acute lung injury to reduce pulmonary dysfunction (HARP-2) trial : study protocol for a randomized controlled trial

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    Acute lung injury (ALI) is a common devastating clinical syndrome characterized by life-threatening respiratory failure requiring mechanical ventilation and multiple organ failure. There are in vitro, animal studies and pre-clinical data suggesting that statins may be beneficial in ALI. The Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in Acute lung injury to Reduce Pulmonary dysfunction (HARP-2) trial is a multicenter, prospective, randomized, allocation concealed, double-blind, placebo-controlled clinical trial which aims to test the hypothesis that treatment with simvastatin will improve clinical outcomes in patients with ALI

    Irreversible pulpitis - A source of antibiotic over-prescription?

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    Antibiotic resistance is a growing public health concern. Antibiotics continue to be prescribed by some clinicians to resolve dental pain even though research indicates that antibiotics are not effective for treating conditions such as irreversible pulpitis. The objective of this study was to determine the extent to which current research and evidence around irreversible pulpitis has been translated into dental practice and the gaps in dentists’ knowledge. An on-line clinical vignette format survey questionnaire about treatment of irreversible pulpitis was distributed to the members of the Academy of Operative Dentistry and Academy of General Dentistry (US based international dental bodies). Their responses were recorded and evaluated. A total of 403 dentists participated in the survey. Over a third (39.3%) indicated they would prescribe antibiotics for symptomatic irreversible pulpitis in a permanent tooth occurring without any signs of systemic infection. The rest indicated they would not prescribe antibiotics; most of them would prescribe an analgesic combined with pulpectomy. Those who had undertaken advanced education training achieved a significantly higher mean knowledge score compared to those with just a primary dental degree (p=0.011). Similarly, full or part time academicians had a higher mean knowledge score than the clinicians who work only in private practice (p=0.014). Some dentists continue to prescribe antibiotics inappropriately for alleviating pain due to irreversible pulpitis. Antibiotic prescribing practices of dentists with advanced education or academic engagement were better as compared to the other participants. There is clear evidence of antibiotic over-prescribing for irreversible pulpitis which needs to be addressed urgently

    Legal determinants of external finance revisited : the inverse relationship between investor protection and societal well-being

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    This paper investigates relationships between corporate governance traditions and quality of life as measured by a number of widely reported indicators. It provides an empirical analysis of indicators of societal health in developed economies using a classification based on legal traditions. Arguably the most widely cited work in the corporate governance literature has been the collection of papers by La Porta et al. which has shown, inter alia, statistically significant relationships between legal traditions and various proxies for investor protection. We show statistically significant relationships between legal traditions and various proxies for societal health. Our comparative evidence suggests that the interests of investors may not be congruent with the interests of wider society, and that the criteria for judging the effectiveness of approaches to corporate governance should not be restricted to financial metrics

    Social capital in relation to depression, musculoskeletal pain, and psychosomatic symptoms: a cross-sectional study of a large population-based cohort of Swedish adolescents

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    <p>Abstract</p> <p>Background</p> <p>Social capital has lately received much attention in health research. The present study investigated whether two measures of subjective social capital were related to psychosomatic symptoms, musculoskeletal pain, and depression in a large population of Swedish adolescents.</p> <p>Methods</p> <p>A total of 7757 13-18 year old students anonymously completed the Survey of Adolescent Life in Vestmanland 2008 which included questions on sociodemographic background, neighbourhood social capital, general social trust, and ill health.</p> <p>Results</p> <p>Low neighbourhood social capital and low general social trust were associated with higher rates of psychosomatic symptoms, musculoskeletal pain, and depression. Individuals with low general social trust had more than three times increased odds of being depressed, three times increased odds of having many psychosomatic symptoms, and double the odds of having many symptoms of musculoskeletal pain.</p> <p>Conclusions</p> <p>The findings make an important contribution to the social capital - health debate by demonstrating relations between social capital factors and self-reported ill health in a young population.</p

    Molecular characterization and phylogenetic analysis of small ruminant lentiviruses isolated from Canadian sheep and goats

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    <p>Abstract</p> <p>Background</p> <p>Small Ruminant Lentiviruses (SRLV) are widespread in Canadian sheep and goats and represent an important health issue in these animals. There is however no data about the genetic diversity of Caprine Arthritis Encephalitis Virus (CAEV) or <it>Maedi Visna </it>Virus (MVV) in this country.</p> <p>Findings</p> <p>We performed a molecular and phylogenetic analysis of sheep and goat lentiviruses from a small geographic area in Canada using long sequences from the <it>gag </it>region of 30 infected sheep and 36 infected goats originating from 14 different flocks. Pairwise DNA distance and phylogenetic analyses revealed that all SRLV sequences obtained from sheep clustered tightly with prototypical <it>Maedi visna </it>sequences from America. Similarly, all SRLV strains obtained from goats clustered tightly with prototypical US CAEV-Cork strain.</p> <p>Conclusions</p> <p>The data reported in this study suggests that Canadian and US SRLV strains share common origins. In addition, the molecular data failed to bring to light any evidence of past cross species transmission between sheep and goats, which is consistent with the type of farming practiced in this part of the country where single species flocks predominate and where opportunities of cross species transmissions are proportionately low.</p

    An Essential Role for the Proximal but Not the Distal Cytoplasmic Tail of Glycoprotein M in Murid Herpesvirus 4 Infection

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    Murid herpesvirus-4 (MuHV-4) provides a tractable model with which to define common, conserved features of gamma-herpesvirus biology. The multi-membrane spanning glycoprotein M (gM) is one of only 4 glycoproteins that are essential for MuHV-4 lytic replication. gM binds to gN and is thought to function mainly secondary envelopment and virion egress, for which several predicted trafficking motifs in its C-terminal cytoplasmic tail could be important. We tested the contribution of the gM cytoplasmic tail to MuHV-4 lytic replication by making recombinant viruses with varying C-terminal deletions. Removing an acidic cluster and a distal YXXΦ motif altered the capsid distribution somewhat in infected cells but had little effect on virus replication, either in vitro or in vivo. In contrast, removing a proximal YXXΦ motif as well completely prevented productive replication. gM was still expressed, but unlike its longer forms showed only limited colocalization with co-transfected gN, and in the context of whole virus appeared to support gN expression less well. We conclude that some elements of the gM cytoplasmic tail are dispensible for MuHV-4 replication, but the tail as a whole is not
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