2,496 research outputs found

    The Economics of Defence

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    Assessing patterns of dissolved methane in shallow aquifers related to Carboniferous and Triassic sedimentary basins, Nova Scotia, Canada

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    The study examines patterns of groundwater methane in shallow aquifers located in Carboniferous and Triassic sedimentary basins in Nova Scotia to improve our understanding of the factors influencing the observed distribution. A combined total of over 800 dissolved methane samples were collected from water wells during surveys conducted in 1975 and 2013. Statistical analyses of the methane data did not detect a significant difference between groupings of methane concentrations for aquifer type, bedrock group, and distance to wetlands. A significant difference, however, was observed between sedimentary basins and bedrock formations, which was largely attributed to localized higher methane concentrations found in the Stellarton Formation/basin compared to other on-shore sedimentary basins of the province. A significant difference was also found between groupings of methane data based on the distance to major stream systems, which was used to indicate topographic position (i.e., valley vs. upslope). The low sample density and percentage of detectable methane concentrations, and the multiple sources of dissolved methane in shallow groundwater in sedimentary basins made it difficult to detect and interpret statistical and spatial trends. Geochemical classification indicates that elevated dissolved methane in well water is associated with sodium dominated groundwater

    Factors associated with not testing for HIV and consistent condom use among men in Soweto, South Africa.

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    BackgroundBesides access to medical male circumcision, HIV testing, access to condoms and consistent condom use are additional strategies men can use to prevent HIV acquisition. We examine male behavior toward testing and condom use.ObjectiveTo determine factors associated with never testing for HIV and consistent condom use among men who never test in Soweto.MethodsA cross-sectional survey in Soweto was conducted in 1539 men aged 18-32 years in 2007. Data were collected on socio-demographic and behavioral characteristics to determine factors associated with not testing and consistent condom use.ResultsOver two thirds (71%) of men had not had an HIV test and the majority (55%, n = 602) were young (18-23). Of those not testing, condom use was poor (44%, n = 304). Men who were 18-23 years (aOR: 2.261, CI: 1.534-3.331), with primary (aOR: 2.096, CI: 1.058-4.153) or high school (aOR: 1.622, CI: 1.078-2.439) education, had sex in the last 6 months (aOR: 1.703, CI: 1.055-2.751), and had ≥1 sexual partner (aOR: 1.749, CI: 1.196-2.557) were more likely not to test. Of those reporting condom use (n = 1036, 67%), consistent condom use was 43% (n = 451). HIV testing did not correlate with condom use.ConclusionLow rates of both condom use and HIV testing among men in a high HIV prevalence setting are worrisome and indicate an urgent need to develop innovative behavioral strategies to address this shortfall. Condom use is poor in this population whether tested or not tested for HIV, indicating no association between condom use and HIV testing

    ARE THERE COORDINATION INSTABILITIES IN THE WALK-TO-RUN TRANSITION? A CASE STUDY USING SELF-ORGANISING MAPS

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    This study investigated multi-dimensional coordination instabilities in the transition between walking and running for a 26 year old female runner using self-organising maps (SOMs). We found different multi-dimensional coordination patterns for walking and running using the output from SOMs as stride trajectories on U-matrices and attractor diagrams. In the second experimental procedure, the participant showed clear transient multi-stability, or instability, at 8.2 km/h in the transition region for decreasing but not for increasing speeds; this is unlikely to be general across runners. She also showed increased multi-dimensional coordination variability around the transition region. SOMs provide us with a tool to study multi-dimensional coordination and to reduce its complexity to relatively simple map outputs

    The Rotating Quantum Thermal Distribution

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    We show that the rigidly rotating quantum thermal distribution on flat space-time suffers from a global pathology which can be cured by introducing a cylindrical mirror if and only if it has a radius smaller than that of the speed-of-light cylinder. When this condition is met, we demonstrate numerically that the renormalized expectation value of the energy-momentum stress tensor corresponds to a rigidly rotating thermal bath up to a finite correction except on the mirror where there are the usual Casimir divergences.Comment: 8 pages, 2 PostScript figure
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