208 research outputs found

    The State of Utah v. Joseph C. Valdez : Brief of Appellee

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    APPEAL FROM THE THIRD CIRCUIT COURT IN AND FOR TOOELE COUNTY, THE HONORABLE EDWARD A. WATSON PRESIDIN

    A scientific note on the natural merger of two honeybee colonies (Apis mellifera capensis)

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    Natural mergers of honeybee colonies are commonplace in tropical Africa (Hepburn and Radloff, 1998), but their consequences on organizational structure are unknown. Here we determine the spatial distribution and division of labor of workers (Apis mellifera capensis Esch.) following a merger of two colonies. Two unrelated colonies (each ~3000 bees) were placed in threeframe observation hives. When workers emerged from the sealed brood of each colony, they were individually labeled and reintroduced into their respective mother hives. They are referred to as cohorts Aand B, each comprising 300 workers of the same age. The behaviors and positions of all labeled workers and queens were recorded twice daily for 24 days (Kolmes, 1989; Pirk et al., 2000). On day 14 colony B was dequeened, left its nest and merged with colony A on day 15

    Scalable Generation of Synthetic GPS Traces with Real-life Data Characteristics

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    Database benchmarking is most valuable if real-life data and workloads are available. However, real-life data (and workloads) are often not publicly available due to IPR constraints or privacy concerns. And even if available, they are often limited regarding scalability and variability of data characteristics. On the oth

    Spatial variability of CO \u3c inf\u3e 2 uptake in polygonal tundra: Assessing low-frequency disturbances in eddy covariance flux estimates

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    The large spatial variability in Arctic tundra complicates the representative assessment of CO2 budgets. Accurate measurements of these heterogeneous landscapes are, however, essential to understanding their vulnerability to climate change. We surveyed a polygonal tundra lowland on Svalbard with an unmanned aerial vehicle (UAV) that mapped ice-wedge morphology to complement eddy covariance (EC) flux measurements of CO2. The analysis of spectral distributions showed that conventional EC methods do not accurately capture the turbulent CO2 exchange with a spatially heterogeneous surface that typically features small flux magnitudes. Nonlocal (low-frequency) flux contributions were especially pronounced during snowmelt and introduced a large bias of -46 gCm-2 to the annual CO22 budget in conventional methods (the minus sign indicates a higher uptake by the ecosystem). Our improved flux calculations with the ogive optimization method indicated that the site was a strong sink for CO2 in 2015 (82 gCm2). Due to differences in light-use efficiency, wetter areas with lowcentered polygons sequestered 47% more CO2 than drier areas with flat-centered polygons. While Svalbard has experienced a strong increase in mean annual air temperature of more than 2K in the last few decades, historical aerial photographs from the site indicated stable ice-wedge morphology over the last 7 decades. Apparently, warming has thus far not been sufficient to initiate strong ice-wedge degradation, possibly due to the absence of extreme heat episodes in the maritime climate on Svalbard. However, in Arctic regions where ice-wedge degradation has already initiated the associated drying of landscapes, our results suggest a weakening of the CO2 sink in polygonal tundra

    Conformal Transformations of the Wigner Function and Solutions of the Quantum Corrected Vlasov Equation

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    We study conformal properties of the quantum kinetic equations in curved spacetime. A transformation law for the covariant Wigner function under conformal transformations of a spacetime is derived by using the formalism of tangent bundles. The conformal invariance of the quantum corrected Vlasov equation is proven. This provides a basis for generating new solutions of the quantum kinetic equations in the presence of gravitational and other external fields. We use our method to find explicit quantum corrections to the class of locally isotropic distributions, to which equilibrium distributions belong. We show that the quantum corrected stress--energy tensor for such distributions has, in general, a non--equilibrium structure. Local thermal equilibrium is possible in quantum systems only if an underlying spacetime is conformally static (not stationary). Possible applications of our results are discussed.Comment: 30 page

    Snowpack fluxes of methane and carbon dioxide from high Arctic tundra

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    Measurements of the land-atmosphere exchange of the greenhouse gases methane (CH4) and carbon dioxide (CO2) in high Arctic tundra ecosystems are particularly difficult in the cold season, resulting in large uncertainty on flux magnitudes and their controlling factors during this long, frozen period. We conducted snowpack measurements of these gases at permafrost-underlain wetland sites in Zackenberg Valley (NE Greenland, 74°N) and Adventdalen Valley (Svalbard, 78°N), both of which also feature automatic closed chamber flux measurements during the snow-free period. At Zackenberg, cold season emissions were 1 to 2 orders of magnitude lower than growing season fluxes. Perennially, CH4 fluxes resembled the same spatial pattern, which was largely attributed to differences in soil wetness controlling substrate accumulation and microbial activity. We found no significant gas sinks or sources inside the snowpack but detected a pulse in the δ13C-CH4 stable isotopic signature of the soil's CH4 source during snowmelt, which suggests the release of a CH4 reservoir that was strongly affected by methanotrophic microorganisms. In the polygonal tundra of Adventdalen, the snowpack featured several ice layers, which suppressed the expected gas emissions to the atmosphere, and conversely lead to snowpack gas accumulations of up to 86 ppm CH4 and 3800 ppm CO2 by late winter. CH4 to CO2 ratios indicated distinctly different source characteristics in the rampart of ice-wedge polygons compared to elsewhere on the measured transect, possibly due to geomorphological soil cracks. Collectively, these findings suggest important ties between growing season and cold season greenhouse gas emissions from high Arctic tundra

    Insights from the STICH trial: Change in left ventricular size after coronary artery bypass grafting with and without surgical ventricular reconstruction

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    ObjectiveThe present analysis of the Surgical Treatment for Ischemic Heart Failure randomized trial data examined the left ventricular volumes at baseline and 4 months after surgery to determine whether any magnitude of postoperative reduction in end-systolic volume affected survival after coronary artery bypass grafting alone compared with bypass grafting plus surgical ventricular reconstruction.MethodsOf the 1000 patients randomized, 555 underwent an operation and had a paired imaging assessment with the same modality at baseline and 4 months postoperatively. Of the remaining 455 patients, 424 either died before the 4-month study or did not have paired imaging tests and were excluded, and 21 were not considered because they had died before surgery or did not receive surgery.ResultsSurgical ventricular reconstruction resulted in improved survival compared with coronary artery bypass grafting alone when the postoperative end-systolic volume index was 70 mL/m2 or less. However, the opposite was true for patients achieving a postoperative volume index greater than 70 mL/m2. A reduction in the end-systolic volume index of 30% or more compared with baseline was an infrequent event in both treatment groups and did not produce a statistically significant survival benefit with ventricular reconstruction.ConclusionsIn patients undergoing coronary artery bypass grafting plus surgical ventricular reconstruction, a survival benefit was realized compared with bypass alone, with the achievement of a postoperative end-systolic volume index of 70 mL/m2 or less. Extensive ventricular remodeling at baseline might limit the ability of ventricular reconstruction to achieve a sufficient reduction in volume and clinical benefit

    Search for Relativistic Magnetic Monopoles with IceCube

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    We present the first results in the search for relativistic magnetic monopoles with the IceCube detector, a subsurface neutrino telescope located in the South Polar ice cap containing a volume of 1 km3^{3}. This analysis searches data taken on the partially completed detector during 2007 when roughly 0.2 km3^{3} of ice was instrumented. The lack of candidate events leads to an upper limit on the flux of relativistic magnetic monopoles of \Phi_{\mathrm{90%C.L.}}\sim 3\e{-18}\fluxunits for β≥0.8\beta\geq0.8. This is a factor of 4 improvement over the previous best experimental flux limits up to a Lorentz boost γ\gamma below 10710^{7}. This result is then interpreted for a wide range of mass and kinetic energy values.Comment: 11 pages, 11 figures. v2 is minor text edits, no changes to resul
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