55,505 research outputs found

    Large-amplitude capillary waves in electrified fluid sheets

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    Large-amplitude capillary waves on fluid sheets are computed in the presence of a uniform electric field acting in a direction parallel to the undisturbed configuration. The fluid is taken to be inviscid, incompressible and non-conducting. Travelling waves of arbitrary amplitudes and wavelengths are calculated and the effect of the electric field is studied. The solutions found generalize the exact symmetric solutions of Kinnersley (1976) to include electric fields, for which no exact solutions have been found. Long-wave nonlinear waves are also constructed using asymptotic methods. The asymptotic solutions are compared with the full computations as the wavelength increases, and agreement is found to be excellent

    Effects of musically-induced emotions on choice reaction time performance

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    The main objective of the current study was to examine the impact of musically-induced emotions on athletes’ subsequent choice reaction time (CRT) performance. A random sample of 54 tennis players listened to researcher-selected music whose tempo and intensity were modified to yield six different music excerpts (three tempi x two intensities) before completing a CRT task. Affective responses, heart rate (HR), and RTs for each condition were contrasted with white noise and silence conditions. As predicted, faster music tempi elicited more pleasant and aroused emotional states; and higher music intensity yielded both higher arousal (p < .001) and faster subsequent CRT performance (p < .001). White noise was judged significantly less pleasant than all experimental conditions (p < .001); and silence was significantly less arousing than all but one experimental condition (p < .001). The implications for athletes’ use of music as part of a preevent routine when preparing for reactive tasks are discussed

    The Rhesus Factor and Disease Prevention

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    First published by the Wellcome Trust Centre for the History of Medicine at UCL, 2004. ©The Trustee of the Wellcome Trust, London, 2004. All volumes are freely available online at: www.history.qmul.ac.uk/research/modbiomed/wellcome_witnesses/Annotated and edited transcript of a Witness Seminar held on 3 June 2003. Introduction by Professor Doris T Zallen.Annotated and edited transcript of a Witness Seminar held on 3 June 2003. Introduction by Professor Doris T Zallen.Annotated and edited transcript of a Witness Seminar held on 3 June 2003. Introduction by Professor Doris T Zallen.Annotated and edited transcript of a Witness Seminar held on 3 June 2003. Introduction by Professor Doris T Zallen.Annotated and edited transcript of a Witness Seminar held on 3 June 2003. Introduction by Professor Doris T Zallen.Annotated and edited transcript of a Witness Seminar held on 3 June 2003. Introduction by Professor Doris T Zallen.Consists of the edited transcripts of Witness SeThe prevention of rhesus disease of the newborn is a stunning medical success story. This disease afflicted thousands of newborns each year, causing serious health problems, even death. Yet from the early 1940s to the 1970s – British and American researchers uncovered the basis of the disease and developed the medical intervention that could prevent its occurrence. Many of the key steps leading to this remarkable achievement took place at the University of Liverpool School of Medicine. Chaired by Professor Sir David Weatherall, this Witness Seminar examines the factors that triggered these studies and the challenges that confronted scientists and clinicians; the intellectual, institutional, and social factors that guided the work; the crucial insights; and the vistas that the prevention of rhesus disease has opened in fetal medicine. Participants include Professor Robin Coombs, the late Professor Ronald Finn, Dr Nevin Hughes-Jones, Professor Patrick Mollison, Dr Archie Norman, Dr Derrick Tovey, Professor Charles Whitfield, Professor John Woodrow and Professor Doris Zallen. Zallen, D T, Christie D A, Tansey E M. (eds) (2004) The Rhesus factor and disease prevention, Wellcome Witnesses to Twentieth Century Medicine, vol. 22. London: The Wellcome Trust Centre for the History of Medicine at UCL. ISBN 978 0 85484 099 1minars organized by the History of Twentieth Century Medicine Group and held at the Wellcome Institute for the History of Medicine.The Wellcome Trust Centre for the History of Medicine at University College London is funded by the Wellcome Trust,which is a registered charity, no. 210183

    Faster K-Means Cluster Estimation

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    There has been considerable work on improving popular clustering algorithm `K-means' in terms of mean squared error (MSE) and speed, both. However, most of the k-means variants tend to compute distance of each data point to each cluster centroid for every iteration. We propose a fast heuristic to overcome this bottleneck with only marginal increase in MSE. We observe that across all iterations of K-means, a data point changes its membership only among a small subset of clusters. Our heuristic predicts such clusters for each data point by looking at nearby clusters after the first iteration of k-means. We augment well known variants of k-means with our heuristic to demonstrate effectiveness of our heuristic. For various synthetic and real-world datasets, our heuristic achieves speed-up of up-to 3 times when compared to efficient variants of k-means.Comment: 6 pages, Accepted at ECIR 201
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