11 research outputs found

    Effects of salinity and waterlogging on the vegetation of Lake Toolibin, Western Australia

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    Increased rates of tree senescence and mortality in and adjacent to an ephemeral lake in the Western Australian wheatbelt have been attributed to increased levels of soil salinity and inundation following agricultural clearing. Winter lake salinities approximate freshwater lake values, but during periods when the lake is dry, capillary rise of groundwater is thought to increase surface soil salinity. An undescribed species of Melaleuca and Casuarina obesa dominated the seasonally inundated regions of the lake bed. Aeolian deposits of higher elevation were dominated by Eucalyptus loxophleba, Allocasuarina huegeliana or species of Banksia. Woodland of E. oleosa var. longicornis and E. salmonophloia occurred predominantly on upland fluviatile deposits of sand and sandy clays. Measurements of soil salinity and the calculation of percentage inundation from tree elevations and observations of tree vigour and xylem pressure potential response indicated that tree deaths in Melaleuca sp. and C. obesa were due to increased levels of salinity. Deaths and low vigours in E. rudis were attributed to both increasing salinities and prolonged inundation. We believe control of ground water levels should be a major consideration in the preservation of this ephemeral lake and the water fowl populations it supports

    An international investigation into O red blood cell unit administration in hospitals: The GRoup O Utilization Patterns (GROUP) study

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    Background: Transfusion of group O blood to non‐O recipients, or transfusion of D– blood to D+ recipients, can result in shortages of group O or D– blood, respectively. This study investigated RBC utilization patterns at hospitals around the world and explored the context and policies that guide ABO blood group and D type selection practices. Study design and methods: This was a retrospective study on transfusion data from the 2013 calendar year. This study included a survey component that asked about hospital RBC selection and transfusion practices and a data collection component where participants submitted information on RBC unit disposition including blood group and D type of unit and recipient. Units administered to recipients of unknown ABO or D group were excluded. Results: Thirty‐eight hospitals in 11 countries responded to the survey, 30 of which provided specific RBC unit disposition data. Overall, 11.1% (21,235/191,397) of group O units were transfused to non‐O recipients; 22.6% (8777/38,911) of group O D– RBC units were transfused to O D+ recipients, and 43.2% (16,800/38,911) of group O D– RBC units were transfused to recipients that were not group O D–. Disposition of units and hospital transfusion policy varied within and across hospitals of different sizes, with transfusion of group O D– units to non‐group O D– patients ranging from 0% to 33%. Conclusion: A significant proportion of group O and D– RBC units were transfused to compatible, nonidentical recipients, although the frequency of this practice varied across sites

    Measurement of the helicity asymmetry E\mathbb{E} for the γ⃗p⃗→pπ0\vec{\gamma}\vec{p} \to p \pi^0 reaction in the resonance region

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    International audienceThe double-spin-polarization observable E\mathbb{E} for γ⃗p⃗→pπ0\vec{\gamma}\vec{p}\to p\pi^0 has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies EÎłE_\gamma from 0.367 to 2.173 GeV2.173~\mathrm{GeV} (corresponding to center-of-mass energies from 1.240 to 2.200 GeV2.200~\mathrm{GeV}) for pion center-of-mass angles, cosâĄÎžÏ€0c.m.\cos\theta_{\pi^0}^{c.m.}, between -0.86 and 0.82. These new CLAS measurements cover a broader energy range and have smaller uncertainties compared to previous CBELSA data and provide an important independent check on systematics. These measurements are compared to predictions as well as new global fits from The George Washington University, Mainz, and Bonn-Gatchina groups. Their inclusion in multipole analyses will refine our understanding of the single-pion production contribution to the Gerasimov-Drell-Hearn sum rule and improve the determination of resonance properties
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