5,113 research outputs found

    Forecasting basketball players’ performance using sparse functional data

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    Statistics and analytic methods are becoming increasingly important in basketball. In particular, predicting players’ performance using past observations is a considerable challenge. The purpose of this study is to forecast the future behavior of basketball players. The available data are sparse functional data, which are very common in sports. So far, however, no forecasting method designed for sparse functional data has been used in sports. A methodology based on two methods to handle sparse and irregular data, together with the analogous method and functional archetypoid analysis is proposed. Results in comparison with traditional methods show that our approach is competitive and additionally provides prediction intervals. The methodology can also be used in other sports when sparse longitudinal data are available

    Feasibility of Focused Cardiac Ultrasound in Pre-participation Screening

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    Objective: Current American Heart Association (AHA) guidelines for pre-participation athletic screening recommend a 12-point history and exam to minimize the risk of sudden cardiac death. We tested the hypothesis that focused cardiac ultrasound (FCU) performed and simultaneously interpreted by a cardiologist using a handheld ultrasound device would be a feasible addition. Methods: We performed pre-participation screening according to AHA recommendations on high school athletes in a multi-purpose room at their school. In addition to the standard 12-point assessment, a cardiologist simultaneously performed and interpreted a FCU on each athlete using a handheld ultrasound. Results: The mean age of the athletes was 16.6 ± 3.4 years; 68% were male. No evidence of left ventricular hypertrophy, cardiomyopathy, bicuspid aortic valve, or aortopathy was identified. Coronary ostia could not be visualized. Echocardiography added 1.35 ± 0.51 minutes to the standard exam. Conclusion: This feasibility study suggests that the addition of handheld echocardiography with real-time interpretation performed by a cardiologist to a standard AHA pre-participation screening adds less than two minutes of time to the assessment. While the study is not as comprehensive as an office based echocardiogram, it can provide valuable information which may be useful in ruling out some of the most common causes of sudden cardiac death in the young athlete or in selecting those who would benefit from further testing

    Relativistic Proton Production During the 14 July 2000 Solar Event: The Case for Multiple Source Mechanisms

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    Protons accelerated to relativistic energies by transient solar and interplanetary phenomena caused a ground-level cosmic ray enhancement on 14 July 2000, Bastille Day. Near-Earth spacecraft measured the proton flux directly and ground-based observatories measured the secondary responses to higher energy protons. We have modelled the arrival of these relativistic protons at Earth using a technique which deduces the spectrum, arrival direction and anisotropy of the high-energy protons that produce increased responses in neutron monitors. To investigate the acceleration processes involved we have employed theoretical shock and stochastic acceleration spectral forms in our fits to spacecraft and neutron monitor data. During the rising phase of the event (10:45 UT and 10:50 UT) we find that the spectrum between 140 MeV and 4 GeV is best fitted by a shock acceleration spectrum. In contrast, the spectrum at the peak (10:55 UT and 11:00 UT) and in the declining phase (11:40 UT) is best fitted with a stochastic acceleration spectrum. We propose that at least two acceleration processes were responsible for the production of relativistic protons during the Bastille Day solar event: (1) protons were accelerated to relativistic energies by a shock, presumably a coronal mass ejection (CME). (2) protons were also accelerated to relativistic energies by stochastic processes initiated by magnetohydrodynamic (MHD) turbulence.Comment: 38 pages, 9 figures, accepted for publication in the Astrophysical Journal, January, 200

    Fractal-like Distributions over the Rational Numbers in High-throughput Biological and Clinical Data

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    Recent developments in extracting and processing biological and clinical data are allowing quantitative approaches to studying living systems. High-throughput sequencing, expression profiles, proteomics, and electronic health records are some examples of such technologies. Extracting meaningful information from those technologies requires careful analysis of the large volumes of data they produce. In this note, we present a set of distributions that commonly appear in the analysis of such data. These distributions present some interesting features: they are discontinuous in the rational numbers, but continuous in the irrational numbers, and possess a certain self-similar (fractal-like) structure. The first set of examples which we present here are drawn from a high-throughput sequencing experiment. Here, the self-similar distributions appear as part of the evaluation of the error rate of the sequencing technology and the identification of tumorogenic genomic alterations. The other examples are obtained from risk factor evaluation and analysis of relative disease prevalence and co-mordbidity as these appear in electronic clinical data. The distributions are also relevant to identification of subclonal populations in tumors and the study of the evolution of infectious diseases, and more precisely the study of quasi-species and intrahost diversity of viral populations

    Neurofilaments form flexible bundles during neuritogenesis in culture and in mature axons in situ

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    Neurofilaments (NFs) undergo cation-dependent phospho-mediated associations with each other and other cytoskeletal elements that support axonal outgrowth. Progressive NF-NF associations generate a resident, bundled population that undergoes exchange with transporting NFs. We examined the properties of bundled NFs. Bundles did not always display a fully linear profile but curved and twisted at various points along the neurite length. Bundles retracted faster than neurites and retracted bundles did not expand following extraction with Triton, indicating that they coiled passively rather than due to pressure from the cell. Bundles consisted of helically wound NFs, which may provide flexibility necessary for turning of growing axons during pathfinding. Interactions between NFs and other cytoskeletal elements may be disrupted en masse during neurite retraction or regionally during remodeling. It is suggested that bundles within long axons that cannot be fully retracted into the soma could provide maintain proximal support yet still allow more distal flexibility for remodeling and changing direction during pathfinding

    Social presence in the 21st Century: an adjustment to the Community of Inquiry framework

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    The Community of Inquiry framework, originally proposed by Garrison, Anderson and Archer (2000) identifies teaching, social and cognitive presences as central to a successful online educational experience. This article presents the findings of a study conducted in Uruguay between 2007 and 2010. The research aimed to establish the role of cognitive, social and teaching presences in the professional development of 40 English language teachers on Continuous Professional Development (CPD) programmes delivered in blended learning settings. The findings suggest that teaching presence and cognitive presence have themselves 'become social'. The research points to social presence as a major lever for engagement, sense-making and peer support. Based on the patterns identified in the study, this article puts forward an adjustment to the Community of Inquiry framework, which shows social presence as more prominent within the teaching and cognitive constructs than the original version of the framework suggests

    Sex and Racial/Ethnic Differences in Cardiovascular Disease Risk Factor Treatment and Control Among Individuals With Diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA)

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    OBJECTIVE To examine sex and racial/ethnic differences in cardiovascular risk factor treatment and control among individuals with diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA). RESEARCH DESIGN AND METHODS This study was an observational study examining mean levels of cardiovascular risk factors and proportion of subjects achieving treatment goals. RESULTS The sample included 926 individuals with diabetes. Compared with men, women were 9% less likely to achieve LDL cholesterol <130 mg/dl (adjusted prevalence ratio 0.91 [0.83-0.99]) and systolic blood pressure (SBP) <130 mmHg (adjusted prevalence ratio 0.91 [0.85-0.98]). These differences diminished over time. A lower percentage of women used aspirin (23 vs. 33%; P < 0.001). African American and Hispanic women had higher mean levels of SBP and lower prevalence of aspirin use than non-Hispanic white women. CONCLUSIONS Women with diabetes had unfavorable cardiovascular risk factor profiles compared with men. African American and Hispanic women had less favorable profiles than non-Hispanic white women

    Future challenges in cephalopod research

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    We thank Anto´nio M. de Frias Martins, past President of the Unitas Malacologica and Peter Marko, President of the American Malacological Society for organizing the 2013 World Congress of Malacology, and the Cephalopod International Advisory Committee for endorsing a symposium held in honour of Malcolm R. Clarke. In particular, we would like to thank the many professional staff from the University of the Azores for their hospitality, organization, troubleshooting and warm welcome to the Azores. We also thank Malcolm Clarke’s widow, Dorothy, his daughter Zoe¨, Jose´ N. Gomes-Pereira and numerous colleagues and friends of Malcolm’s from around the world for joining us at Ponta Delgada. We are grateful to Lyndsey Claro (Princeton University Press) for granting copyright permissions.Peer reviewedPublisher PD

    Energy Landscape and Global Optimization for a Frustrated Model Protein

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    The three-color (BLN) 69-residue model protein was designed to exhibit frustrated folding. We investigate the energy landscape of this protein using disconnectivity graphs and compare it to a Go model, which is designed to reduce the frustration by removing all non-native attractive interactions. Finding the global minimum on a frustrated energy landscape is a good test of global optimization techniques, and we present calculations evaluating the performance of basin-hopping and genetic algorithms for this system.Comparisons are made with the widely studied 46-residue BLN protein.We show that the energy landscape of the 69-residue BLN protein contains several deep funnels, each of which corresponds to a different β-barrel structure
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