359 research outputs found

    Comparison of Wide and Compact Fourth Order Formulations of the Navier-Stokes Equations

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    In this study the numerical performances of wide and compact fourth order formulation of the steady 2-D incompressible Navier-Stokes equations will be investigated and compared with each other. The benchmark driven cavity flow problem will be solved using both wide and compact fourth order formulations and the numerical performances of both formulations will be presented and also the advantages and disadvantages of both formulations will be discussed

    Numerical Performance of Compact Fourth Order Formulation of the Navier-Stokes Equations

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    In this study the numerical performance of the fourth order compact formulation of the steady 2-D incompressible Navier-Stokes equations introduced by Erturk et al. (Int. J. Numer. Methods Fluids, 50, 421-436) will be presented. The benchmark driven cavity flow problem will be solved using the introduced compact fourth order formulation of the Navier-Stokes equations with two different line iterative semi-implicit methods for both second and fourth order spatial accuracy. The extra CPU work needed for increasing the spatial accuracy from second order (O(x2)) to fourth order (O(x4)) formulation will be presented

    Evaluation of an interactive, case-based review session in teaching medical microbiology

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    <p>Abstract</p> <p>Background</p> <p>Oklahoma State University-Center for Health Sciences (OSU-CHS) has replaced its microbiology wet laboratory with a variety of tutorials including a case-based interactive session called Microbial Jeopardy!. The question remains whether the time spent by students and faculty in the interactive case-based tutorial is worthwhile? This study was designed to address this question by analyzing both student performance data and assessing students' perceptions regarding the tutorial.</p> <p>Methods</p> <p>Both quantitative and qualitative data were used in the current study. Part One of the study involved assessing student performance using archival records of seven case-based exam questions used in the 2004, 2005, 2006, and 2007 OSU-CHS Medical Microbiology course. Two sample t-tests for proportions were used to test for significant differences related to tutorial usage. Part Two used both quantitative and qualitative means to assess student's perceptions of the Microbial Jeopardy! session. First, a retrospective survey was administered to students who were enrolled in Medical Microbiology in 2006 or 2007. Second, responses to open-ended items from the 2008 course evaluations were reviewed for comments regarding the Microbial Jeopardy! session.</p> <p>Results</p> <p>Both student performance and student perception data support continued use of the tutorials. Quantitative and qualitative data converge to suggest that students like and learn from the interactive, case-based session.</p> <p>Conclusion</p> <p>The case-based tutorial appears to improve student performance on case-based exam questions. Additionally, students perceived the tutorial as helpful in preparing for exam questions and reviewing the course material. The time commitment for use of the case-based tutorial appears to be justified.</p

    NMR-based metabolomic profiling of urine: Evaluation for application in prostate cancer detection

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    Detection of prostate cancer (PCa) and distinguishing indolent versus aggressive forms of the disease is a critical clinical challenge. The current clinical test is circulating prostate-specific antigen levels, which faces particular challenges in cancer diagnosis in the range of 4 to 10 ng/mL. Thus, a concerted effort toward building a noninvasive biomarker panel has developed. In this report, the hypothesis that nuclear magnetic resonance (NMR)-derived metabolomic profiles measured in the urine of biopsy-negative versus biopsy-positive individuals would nominate a selection of potential biomarker signals was investigated. 1H NMR spectra of urine samples from 317 individuals (111 biopsy-negative, 206 biopsy-positive) were analyzed. A double cross-validation partial least squares-discriminant analysis modeling technique was utilized to nominate signals capable of distinguishing the two classes. It was observed that after variable selection protocols were applied, a subset of 29 variables produced an area under the curve (AUC) value of 0.94 after logistic regression analysis, whereas a “master list” of 18 variables produced a receiver operating characteristic ROC) AUC of 0.80. As proof of principle, this study demonstrates the utility of NMR-based metabolomic profiling of urine biospecimens in the nomination of PCa-specific biomarker signals and suggests that further investigation is certainly warranted

    A Standardised Procedure for Evaluating Creative Systems: Computational Creativity Evaluation Based on What it is to be Creative

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    Computational creativity is a flourishing research area, with a variety of creative systems being produced and developed. Creativity evaluation has not kept pace with system development with an evident lack of systematic evaluation of the creativity of these systems in the literature. This is partially due to difficulties in defining what it means for a computer to be creative; indeed, there is no consensus on this for human creativity, let alone its computational equivalent. This paper proposes a Standardised Procedure for Evaluating Creative Systems (SPECS). SPECS is a three-step process: stating what it means for a particular computational system to be creative, deriving and performing tests based on these statements. To assist this process, the paper offers a collection of key components of creativity, identified empirically from discussions of human and computational creativity. Using this approach, the SPECS methodology is demonstrated through a comparative case study evaluating computational creativity systems that improvise music

    Intrusive memories and depression following recent non-traumatic negative life events in adolescents

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    Background: Research in adults suggests that intrusive memories are not just found in individuals with post-traumatic stress disorder (PTSD), yet there is little evidence concerning the phenomenology of intrusive memories in children and adolescents. The present study investigated the frequency of intrusive memories following a recent negative event in an adolescent school sample, and considered the application of cognitive theory to understanding the maintenance of intrusive memories of recent negative events, and their role in maintaining depression. Methods: High school students (aged 11-18 years; n = 231) completed questionnaires concerning affect experienced during a recent negative event, the frequency of subsequent intrusive memories, memory quality, thought suppression, post-traumatic stress and depressive symptoms. Results: Most participants had experienced at least one intrusive memory in the previous week, at similar rates for traumatic events and life events. In non-trauma exposed youth, peri-event affect and memory quality accounted for unique variance in a regression model of intrusive memory frequency, while peri-event affect, memory quality, and intrusive memory frequency accounted for unique variance in a regression model of depression. Limitations: The study needs replication in younger children. Interview methods may be required to ensure that intrusive memories are being assessed and not intrusive thoughts or ruminations. Conclusions: Intrusive memories are common reaction to negative events in adolescents, and may be involved in maintaining subsequent depressed mood. The nature of event memories may have a role in the maintenance of such psychopathology, and may be a target for psychological interventions in this age group

    Early Adolescent Depressive Symptoms: Prediction from Clique Isolation, Loneliness, and Perceived Social Acceptance

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    This study examined whether clique isolation predicted an increase in depressive symptoms and whether this association was mediated by loneliness and perceived social acceptance in 310 children followed from age 11–14 years. Clique isolation was identified through social network analysis, whereas depressive symptoms, loneliness, and perceived social acceptance were assessed using self ratings. While accounting for initial levels of depressive symptoms, peer rejection, and friendlessness at age 11 years, a high probability of being isolated from cliques from age 11 to 13 years predicted depressive symptoms at age 14 years. The link between clique isolation and depressive symptoms was mediated by loneliness, but not by perceived social acceptance. No sex differences were found in the associations between clique isolation and depressive symptoms. These results suggest that clique isolation is a social risk factor for the escalation of depressive symptoms in early adolescence. Implications for research and prevention are discussed

    Repeated exposure to socioeconomic disadvantage and health selection as life course pathways to mid-life depressive and anxiety disorders

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    The biomedical examination was funded by Medical Research Council [G0000934], awarded under the Health of the Public initiative. Charlotte Clark is supported by an Engineering and Physical Sciences Research Fellowship. Bryan Rodgers is supported by Research Fellowships Nos 148948 and 366758 and by Program Grant No. 179805 from the National Health and Medical Research Council of Australia. Research at the Institute of Child Health and Great Ormond Street Hospital for Children NHS Trust benefits from R&D funding received from the NHS Executive
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