6,377 research outputs found

    Effects of Three Swim Strokes Over 25 Yards in Labor-Wear with a Personal Flotation Device

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    We determined how three different swim strokes (breast, back, and American crawl) were affected by standard labor-wear while wearing a personal flotation device (PFD) over 22.8 meters (25 yards). The main research questions were, (1) which stroke would yield the fastest times over 22.8 meters and (2) Would there be a difference in the swim times between male and female subjects?  We addressed these questions with three hypotheses addressing whether or not there would be a statistically significant difference among the three strokes, and whether or not gender would have an effect on performance of the different strokes. The mean 22.8-m elementary back stroke swim time for all subjects (n = 51) was 59.98 sec; for the breast stroke it was 46.05 sec and for the crawl stroke it was 46.48 sec.  An ANOVA generated a P-value of less than .0001. Thus, we rejected null hypothesis 1 in favor of research hypothesis 1 at a significance level of 0.05. There was a difference in swim times over 22.8-m for each stroke for all subjects, with breast stroke being the fastest and the elementary back stroke being the slowest.  The mean 22.8-m elementary back stroke swim time for male subjects (n = 26) was 51.04 sec; for the breast stroke it was 41.41 sec and for the crawl stroke it was 34.73 sec.  An ANOVA generated a P-value of less than .0001. Thus, we rejected null hypothesis 2 in favor of research hypothesis 2 at a significance level of 0.05.   There was a difference in swim times over 22.8-m for each stroke, with the crawl stroke being the fastest and the elementary back stroke being the slowest.  The mean 22.8-m elementary back stroke swim time for female subjects (n = 25) was 69.28 sec; for the breast stroke it was 50.87 sec and for the crawl stroke it was 58.71 sec.  An ANOVA generated a P-value of .001. Thus, we rejected null hypothesis 3 in favor of research hypothesis 3 at a significance level of 0.05. There was a difference in swim times over 22.8-m for each stroke, with the breast stroke being the fastest and the elementary back stroke being the slowest

    Application of Tube Fishways to Weirs

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    Hydraulic barriers such as weirs and dams impede the natural connectivity of riverine systems and severely disrupt the migratory behaviours of fish. Even small weirs can prevent upstream fish migration. The consequent reduction in freshwater fishes' habitat access have caused a global decline in fish populations. Fishways aim to enable migratory fish passage, however relatively few hydraulic barriers in Australia are fitted with a fishway. A review of common fish barriers and an evaluation of current fishway designs on weirs is presented. A novel fishway system, the Tube Fishway, which aims to address existing fishway shortcomings is described. This contribution discusses the diversity of weir types in Australia and potential approaches to the installation and operation of Tube Fishways on these structures. Field experiments to evaluate the effectiveness of Tube Fishway design, installation and operation are described

    Branching diffusion processes

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    Effects of Standard Labor-Wear on Swimming and Treading Water

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    We tested the hypothesis that occupational clothing would impair performance during swimming. The sub questions included: (1) Will the standard work wear of a railway worker or laborer impede swimming ability? (2) Will this clothing impact the individual’s ability to tread water? We addressed the research questions with three hypotheses. Analysis showed statistically significant p-values and all three null hypotheses were rejected in favor of the three research hypotheses, showing strong evidence that standard labor wear had adverse effects on 11.43 meter/12.5 yard swim time, water treading time and rate of perceived exertion (RPE) during water treading. The mean swim time more than doubled when the subjects wore standard labor-wear and their average rate of perceived exertion increased from 11.6 in standard swim wear to 17.1 in standard laborwear. It may be beneficial for those workers who work near water to be exposed to educational programs that allow in-water experiences so they develop an understanding of their abilities in, and respect for, the water

    New Distributional Records for Freshwater Mussels in the Ouachita River, Arkansas

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    Two freshwater mussel species thought to have been extirpated from Arkansas have recently been rediscovered in the Ouachita River in the vicinity of Camden. Prior to this survey, Wheeler (1918) last reported Arkansia wheeleri Ortmann and Walker, the Ouachita rock-pocketbook, and Cumberlandia monodonta (Say), the spectaclecase, from the Ouachita River near Arkadelphia. Quadrula apiculata (Lea), the southern mapleleaf, has been reported from Arkansas on two occasions, but due to taxonomic uncertainty, it has not been recognized in recent compilations of Arkansas freshwater mussels. During this survey, the southern mapleleaf was collected from the Ouachita River which verifies its occurrence within Arkansas. Quadrula fragosa (Conrad), the winged mapleleaf, is reported as a new state record. Arkansia wheeleri and Quadrula fragosa are listed as threatened and endangered species, respectively, by the U.S. Fish and Wildlife Service

    Month-Timescale Optical Variability in the M87 Jet

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    A previously inconspicuous knot in the M87 jet has undergone a dramatic outburst and now exceeds the nucleus in optical and X-ray luminosity. Monitoring of M87 with the Hubble Space Telescope and Chandra X-ray Observatory during 2002-2003, has found month-timescale optical variability in both the nucleus and HST-1, a knot in the jet 0.82'' from the nucleus. We discuss the behavior of the variability timescales as well as spectral energy distribution of both components. In the nucleus, we see nearly energy-independent variability behavior. Knot HST-1, however, displays weak energy dependence in both X-ray and optical bands, but with nearly comparable rise/decay timescales at 220 nm and 0.5 keV. The flaring region of HST-1 appears stationary over eight months of monitoring. We consider various emission models to explain the variability of both components. The flares we see are similar to those seen in blazars, albeit on longer timescales, and so could, if viewed at smaller angles, explain the extreme variability properties of those objects.Comment: 4 pages, 3 figures, ApJ Lett., in pres

    Welfare Plastic: The Transformation of Public Assistance in the Electronic Age

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    Several states have developed electronic benefit transfer (EBT) systems to deliver cash assistance and food stamp benefits. These systems establish electronic account balances which recipients access through the use of a debit card at terminals such as bank automatic teller machines or transaction authorization machines like those that validate credit card charges. We examine the potential effects of such systems on involved stakeholders, including government agencies, benefit recipients, financial institutions, and food retailers. Overall, each stakeholder group benefits from EBT, but some subgroups do not fare as well. Several key issues are identified

    Effects of Standard Labor-Wear on Swimming and Treading Water

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    We tested the hypothesis that occupational clothing would impair performance during swimming. The sub questions included: (1) Will the standard work wear of a railway worker or laborer impede swimming ability? (2) Will this clothing impact the individual’s ability to tread water? We addressed the research questions with three hypotheses. Analysis showed statistically significant p-values and all three null hypotheses were rejected in favor of the three research hypotheses, showing strong evidence that standard labor wear had adverse effects on 11.43 meter/12.5 yard swim time, water treading time and rate of perceived exertion (RPE) during water treading. The mean swim time more than doubled when the subjects wore standard labor-wear and their average rate of perceived exertion increased from 11.6 in standard swim wear to 17.1 in standard laborwear. It may be beneficial for those workers who work near water to be exposed to educational programs that allow in-water experiences so they develop an understanding of their abilities in, and respect for, the water
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