126 research outputs found

    The Drink Habit.

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    Remote measurement utilizing NASA's scanning laser Doppler systems. Volume 2: Laser Doppler dust devil velocity profile measurement program

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    The first detailed velocity profile data on thermally induced dust vortices are presented. These dust devils will be analyzed and studied to determine their flow fields and origin in an effort to correlate this phenomena with the generation and characteristics of tornadoes. A continuing effort to increase mankind's knowledge of vortex and other meteorological phenomena will hopefully allow the prediction of tornado occurrence, their path, and perhaps eventually even lead to some technique for their destruction

    Self-presentation concerns may contribute towards the understanding of athletes' affect when trialling for a new sports team

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    A vignette-based experimental manipulation was used to examine the impact of self-presentation concerns on athletes’ affect and cognitive appraisal. Others’ reactions were described, so as to emphasize or de-emphasize self-presentation concerns. Athletes given cause to believe that they were generating unfavourable impressions experienced more negative affect and reported more threat-based appraisal. Athletes exposed to information de-emphasizing self-presentation concerns experienced more positive affect and reported more of a challenge-based appraisal. The findings indicate a potential opportunity (e.g., de-emphasising self-presentation concerns, providing a supportive interpersonal environment) that others (e.g., coaches and teammates) could act on to improve athlete experiences during sports trials

    Remote measurement utilizing NASA's scanning laser Doppler systems. Volume 1. Laser Doppler wake vortex tracking at Kennedy Airport

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    Test operations of the Scanning Laser Doppler System (SLDS) at Kennedy International Airport (KIA) during August 1974 through June 1975 are reported. A total of 1,619 data runs was recorded with a totally operational system during normal landing operations at KIA. In addition, 53 data runs were made during cooperative flybys with the C880 for a grand total of 1672 recorded vortex tracks. Test crews were in attendance at KIA for 31 weeks, of which 25 weeks were considered operational and the other six were packing, unpacking, setup and check out. Although average activity equates to 67 recorded landing operations per week, two periods of complete runway inactivity spanned 20 days and 13 days, respectively. The operation frequency therefore averaged about 88 operations per week

    Workload profiles prior to injury in professional soccer players

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    © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. This study examined if a particular profile of internal and external workload existed prior to injury. Forty-five professional soccer players were monitored over two seasons. For each non-contact injury, a profile of workload variables was determined for 4 weeks and expressed as (i) an absolute, (ii) week-to-week change and (iii) relative to the player’s season mean. Variables included exposure, session rating of perceived exertion (s-RPE) workload, total distance, low-, high-, very-high-speed running distance, mean speed, bodyload, monotony and strain. Acute:chronic workload ratio was also calculated and sensitivity of the relative workload was tested. Absolute and relative exposure and s-RPE workload were greater in all 3 weeks compared to the injury week (P  0.05). Acute:chronic workload ratio for s-RPE was significantly greater than acute:chronic workload ratio for very-high-speed running (P = 0.04). A workload threshold of 114% of a player’s season mean reported low sensitivity and specificity for exposure (25.6[20.2–33.5]% and 73.9[22.6–28.2]%,) and s-RPE workload (16.3[12.6–24.9]% and 79.9[20.3–26.1]%, respectively). No specific load profile existed, although high-sustained exposure and s-RPE were evident for the 3 weeks prior to injury. Consequently, load prescription should be aware of sustained high workloads

    The photoionization dynamics of the three structural isomers of dichloroethene

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    Using tunable vacuum-UV radiation from a synchrotron, the threshold photoelectron spectrum, threshold photoelectron photoion coincidence spectrum and ion breakdown diagram of the 1,1, cis-1,2 and trans-1,2 isomers of C2_2H2_2Cl2_2 have been recorded in the range 9-23 eV. The energies of the peaks in the threshold photoelectron spectrum are in good agreement with outer-valence Greens function caculations. The major difference between the isomers, both predicted and observed experimentally is that the F and G states of C2_2H2_2Cl2+_2^+ are approximately degenerate for 1,1 and trans-1,2, but well separated for the cis-1,2 isomer. The ground and low-lying valence states of C2_2H2_2Cl2+_2^+ are bound, with higher-lying states dissociating to C2_2H2_2Cl+^+ or C2_2H2+_2^+. The translational kinetic energy release into C2_2H2_2Cl+^+ + Cl is determined as a function of energy. Isolated-state behaviour for the low-lying electronic states of C2_2H2_2Cl2+_2^+ becomes more statistical as the energy increases

    Short-wave infrared barriode detectors using InGaAsSb absorption material lattice matched to GaSb

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    Short-wave infrared barriode detectors were grown by molecular beam epitaxy. An absorption layer composition of In0.28Ga0.72As0.25Sb0.75 allowed for lattice matching to GaSb and cut-off wavelengths of 2.9 μm at 250 K and 3.0 μm at room temperature. Arrhenius plots of the dark current density showed diffusion limited dark currents approaching those expected for optimized HgCdTe-based detectors. Specific detectivity figures of around 7×1010 Jones and 1×1010 Jones were calculated, for 240 K and room temperature, respectively. Significantly, these devices could support focal plane arrays working at higher operating temperatures

    From the track to the ocean : using flow control to improve marine bio-logging tags for cetaceans

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    This project was funded by the National Oceanographic Partnership Program [National Science Foundation via the Office of Naval Research N00014-11-1-0113]. C. Spencer Garborg was supported by a Grove City College Swezey Student Fellowship to Erik Anderson. Mark Johnson was funded by a Marie Curie-Sklodowska grant from the European Union. All supplemental data files are available from the Dryad Digital Repository (doi:10.5061/dryad.4j4m1).Bio-logging tags are an important tool for the study of cetaceans, but superficial tags inevitably increase hydrodynamic loading. Substantial forces can be generated by tags on fast-swimming animals, potentially affecting behavior and energetics or promoting early tag removal. Streamlined forms have been used to reduce loading, but these designs can accelerate flow over the top of the tag. This non-axisymmetric flow results in large lift forces (normal to the animal) that become the dominant force component at high speeds. In order to reduce lift and minimize total hydrodynamic loading this work presents a new tag design (Model A) that incorporates a hydrodynamic body, a channel to reduce fluid speed differences above and below the housing and wing to redirect flow to counter lift. Additionally, three derivatives of the Model A design were used to examine the contribution of individual flow control features to overall performance. Hydrodynamic loadings of four models were compared using computational fluid dynamics (CFD). The Model A design eliminated all lift force and generated up to ~30 N of downward force in simulated 6 m/s aligned flow. The simulations were validated using particle image velocimetry (PIV) to experimentally characterize the flow around the tag design. The results of these experiments confirm the trends predicted by the simulations and demonstrate the potential benefit of flow control elements for the reduction of tag induced forces on the animal.Publisher PDFPeer reviewe

    Transformational teaching, self-presentation motives, and identity in adolescent female physical education

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    This study examined whether teachers’ use of transformational teaching behaviors, as perceived by adolescent girls, in physical education would predict girls’ moderate to vigorous physical activity via mediated effects of physical activity self-presentation motives, physical activity identity, and physical education class engagement. Self-report data were acquired from 273 Scottish high school girls in Grades S1–S3 (the equivalent of Grades 7–9 in North America) at 2 time points separated by 1 week. Significant predictive pathways were found from transformational teaching to girls’ moderate to vigorous physical activity via mediated effects of acquisitive self-presentation motives and physical activity identity. This preliminary study provides a novel contribution to the research area by showing how previously unrelated psychosocial constructs work together to predict adolescent girls’ moderate to vigorous physical activity. Results are discussed in relation to existing literature and future research directions
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