55,505 research outputs found
Large-amplitude capillary waves in electrified fluid sheets
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
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A grounded theory of young tennis players’ use of music to manipulate emotional state
The main objectives of this study were (a) to elucidate young tennis players’ use of music to manipulate emotional states, and (b) to present a model grounded in present data to illustrate this phenomenon and to stimulate further research. Anecdotal evidence suggests that music listening is used regularly by elite athletes as a preperformance strategy, but only limited empirical evidence corroborates such use. Young tennis players (N = 14) were selected purposively for interview and diary data collection. Results indicated that participants consciously selected music to elicit various emotional states; frequently reported consequences of music listening included improved mood, increased arousal, and visual and auditory imagery. The choice of music tracks and the impact of music listening were mediated by a number of factors, including extramusical associations, inspirational lyrics, music properties, and desired emotional state. Implications for the future investigation of preperformance music are discussed
Effects of musically-induced emotions on choice reaction time performance
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
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
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M-FISH analysis shows that complex chromosome aberrations induced by α-particle tracks are cumulative products of localised rearrangements
Complex chromosome aberrations are characteristically induced after exposure to low doses of densely ionising radiation, but little is understood about their formation. To address this, we irradiated human peripheral blood lymphocytes (PBL) in vitro with 0.5 Gy densely ionising α-particles (mean of 1 α-particle/cell) and analysed the chromosome aberrations produced using 24-colour M-FISH. Our data suggest that complex formation is a consequence of direct nuclear α-particle traversal and show that the likely product of illegitimate repair of damage from a single α-particle is a single complex exchange. From an assessment of the ‘cycle structure’ of each complex exchange we predict α-particle-induced damage to be repaired at specific localised sites, and complexes to be formed as cumulative products of this repair
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Chromosome breakpoint distribution of damage induced in peripheral blood lymphocytes by densely ionising radiation
Purpose: To assess the chromosomal breakpoint distribution in human peripheral blood lymphocytes (PBL) after exposure to a low dose of high linear energy transfer (LET) α-particles using the technique of multiplex fluorescence in situ hybridisation (m-FISH).
Materials and methods: Separated PBL were exposed in G0 to 0.5 Gy 238 Pu α-particles, stimulated to divide and harvested ~48-50 hours after exposure. Metaphase cells were assayed by m-FISH and chromosome breaks identified. The observed distribution of breaks were then compared with expected distributions of breaks, calculated on the assumption that the distribution of breaks is random with regard to either chromosome volume or chromosome surface area.
Results: More breaks than expected were observed on chromosomes 2 and 11, however no particular region of either chromosome was identified as significantly contributing to this over-representation. The identification of hot or cold chromosome regions (pter,p,cen,q,qter) varied depending on whether the data were compared according to chromosome volume or surface area.
Conclusions: A deviation from randomness in chromosome breakpoint distribution was observed, and this was greatest when data were compared according to the relative surface area of each individual chromosome (or region). The identification of breaks by m-FISH (i.e. more efficient observation of interchanges than intrachanges) and importance of territorial boundaries on interchange formation are thought to contribute to these differences. The significance of the observed non-random distribution of breaks on chromosomes 2 and 11 in relation to chromatin organisation is unclear
Faster K-Means Cluster Estimation
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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