1,416 research outputs found

    Dietary Supplementation with Organoselenium Accelerates Recovery of Bladder Expression, but Does Not Improve Locomotor Function, Following Spinal Cord Injury

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    Selenium is an essential element required for activity of several antioxidant enzymes, including glutathione peroxidase. Because of the critical role of the antioxidant system in responding to traumatic events, we hypothesized that dietary selenium supplementation would enhance neuroprotection in a rodent model of spinal cord injury. Rats were maintained on either a control or selenium-enriched diet prior to, and following, injury. Dietary selenium supplementation, provided as selenized yeast added to normal rat chow, resulted in a doubling of selenium levels in the spinal cord. Dietary selenium reduced the time required for recovery of bladder function following thoracic spinal cord injury. However, this was not accompanied by improvement in locomotor function or tissue sparing

    Feeding ecology of broadbill swordfish (Xiphias gladius) in the California current

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    Funding: Support for our study includes salary funding from the NOAA Fisheries’ Office of Science and Technology and contract funds from the Cooperative Institute for Marine, Earth, and Atmospheric Systems. The National Observer Program within NOAA Fisheries’ Office of Science and Technology carried out sample collection. While the study fits the scope of work under the coauthors’ performance plans, they received no specific funding for this work. The funders had no role in study design, analysis, decision to publish, or preparation of the manuscript. Acknowledgments This work would not have been possible without the assistance and samples provided by the NMFS Southwest Region Fishery Observer Program and the participating drift gillnet fishermen. We thank several assistant volunteers who helped process the stomach samples. Alexandra Stohs provided research assistance. Mark Lowry, Eric Hochberg and John Hyde helped identify some prey specimens. John Field, Chugey Sepulveda and Scott Aalbers offered science feedback. Barbara Muhling helped create the map. Kristen Koch, Annie Yau, Brad Erisman, Heidi Dewar, Stephanie Flores, Crystal Dombrow, Elan Portner and Ruben Bergtraun provided useful comments on the draft. Debra Losey assisted with library research. We also thank Hiroshi Ohizumi and two anonymous reviewers for their careful critiques that helped improve the manuscript.Peer reviewedPublisher PD

    Forty years studying British politics : the decline of Anglo-America

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    The still present belief some 40 years ago that British politics was both exceptional and superior has been replaced by more theoretically sophisticated analyses based on a wider and more rigorously deployed range of research techniques, although historical analysis appropriately remains important. The American influence on the study of British politics has declined, but the European Union dimension has not been fully integrated. The study of interest groups has been in some respects a fading paradigm, but important questions related to democratic health have still to be addressed. Public administration has been supplanted by public policy, but economic policy remains under-studied. A key challenge for the future is the study of the management of expectations

    Investigation of the ferromagnetic transition in the correlated 4d perovskites SrRu1x_{1-x}Rhx_xO3_3

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    The solid-solution SrRu1x_{1-x}Rhx_xO3_3 (0x10\le x \le1) is a variable-electron-configuration system forming in the nearly-cubic-perovskite basis, ranging from the ferromagnetic 4d4d^4 to the enhanced paramagnetic 4d5d^5. Polycrystalline single-phase samples were obtained over the whole composition range by a high-pressure-heating technique, followed by measurements of magnetic susceptibility, magnetization, specific heat, thermopower, and electrical resistivity. The ferromagnetic order in long range is gradually suppressed by the Rh substitution and vanishes at x0.6x \sim 0.6. The electronic term of specific-heat shows unusual behavior near the critical Rh concentration; the feature does not match even qualitatively with what was reported for the related perovskites (Sr,Ca)RuO3_3. Furthermore, another anomaly in the specific heat was observed at x0.9x \sim 0.9.Comment: Accepted for publication in PR

    Oral rehydration versus intravenous therapy for treating dehydration due to gastroenteritis in children: a meta-analysis of randomised controlled trials

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    BACKGROUND: Despite treatment recommendations from various organizations, oral rehydration therapy (ORT) continues to be underused, particularly by physicians in high-income countries. We conducted a systematic review of randomised controlled trials (RCTs) to compare ORT and intravenous therapy (IVT) for the treatment of dehydration secondary to acute gastroenteritis in children. METHODS: RCTs were identified through MEDLINE, EMBASE, CENTRAL, authors and references of included trials, pharmaceutical companies, and relevant organizations. Screening and inclusion were performed independently by two reviewers in order to identify randomised or quasi-randomised controlled trials comparing ORT and IVT in children with acute diarrhea and dehydration. Two reviewers independently assessed study quality using the Jadad scale and allocation concealment. Data were extracted by one reviewer and checked by a second. The primary outcome measure was failure of rehydration. We analyzed data using standard meta-analytic techniques. RESULTS: The quality of the 14 included trials ranged from 0 to 3 (Jadad score); allocation concealment was unclear in all but one study. Using a random effects model, there was no significant difference in treatment failures (risk difference [RD] 3%; 95% confidence intervals [CI]: 0, 6). The Mantel-Haenzsel fixed effects model gave a significant difference between treatment groups (RD 4%; 95% CI: 2, 5) favoring IVT. Based on the four studies that reported deaths, there were six in the IVT groups and two in ORT. There were no significant differences in total fluid intake at six and 24 hours, weight gain, duration of diarrhea, or hypo/hypernatremia. Length of stay was significantly shorter for the ORT group (weighted mean difference [WMD] -1.2 days; 95% CI: -2.4,-0.02). Phlebitis occurred significantly more often with IVT (number needed to treat [NNT] 33; 95% CI: 25,100); paralytic ileus occurred more often with ORT (NNT 33; 95% CI: 20,100). These results may not be generalizable to children with persistent vomiting. CONCLUSION: There were no clinically important differences between ORT and IVT in terms of efficacy and safety. For every 25 children (95% CI: 20, 50) treated with ORT, one would fail and require IVT. The results support existing practice guidelines recommending ORT as the first course of treatment in appropriate children with dehydration secondary to gastroenteritis

    Mathematical practice, crowdsourcing, and social machines

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    The highest level of mathematics has traditionally been seen as a solitary endeavour, to produce a proof for review and acceptance by research peers. Mathematics is now at a remarkable inflexion point, with new technology radically extending the power and limits of individuals. Crowdsourcing pulls together diverse experts to solve problems; symbolic computation tackles huge routine calculations; and computers check proofs too long and complicated for humans to comprehend. Mathematical practice is an emerging interdisciplinary field which draws on philosophy and social science to understand how mathematics is produced. Online mathematical activity provides a novel and rich source of data for empirical investigation of mathematical practice - for example the community question answering system {\it mathoverflow} contains around 40,000 mathematical conversations, and {\it polymath} collaborations provide transcripts of the process of discovering proofs. Our preliminary investigations have demonstrated the importance of "soft" aspects such as analogy and creativity, alongside deduction and proof, in the production of mathematics, and have given us new ways to think about the roles of people and machines in creating new mathematical knowledge. We discuss further investigation of these resources and what it might reveal. Crowdsourced mathematical activity is an example of a "social machine", a new paradigm, identified by Berners-Lee, for viewing a combination of people and computers as a single problem-solving entity, and the subject of major international research endeavours. We outline a future research agenda for mathematics social machines, a combination of people, computers, and mathematical archives to create and apply mathematics, with the potential to change the way people do mathematics, and to transform the reach, pace, and impact of mathematics research.Comment: To appear, Springer LNCS, Proceedings of Conferences on Intelligent Computer Mathematics, CICM 2013, July 2013 Bath, U

    Methane mole fraction and δ13^{13}C above and below the trade wind inversion at Ascension Island in air sampled by aerial robotics

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    The Authors.Ascension Island is a remote South Atlantic equatorial site, ideal for monitoring tropical background CH4. In September 2014 and July 2015, octocopters were used to collect air samples in Tedlar bags from different heights above and below the well-defined Trade Wind Inversion (TWI), sampling a maximum altitude of 2700 m above mean sea level. Sampling captured both remote air in the marine boundary layer below the TWI and also air masses above the TWI that had been lofted by convective systems in the African tropics. Air above the TWI was characterized by higher CH4_{4}, but no distinct shift in δ13^{13}C was observed compared to the air below. Back trajectories indicate that lofted CH4_{4} emissions from Southern Hemisphere Africa have bulk δ13^{13}CCH4_{CH4} signatures similar to background, suggesting mixed emissions from wetlands, agriculture, and biomass burning. The campaigns illustrate the usefulness of unmanned aerial system sampling and Ascension's value for atmospheric measurement in an understudied region.This work was part of the investigation of the southern methane anomaly: causes, implications, and relevance to past global events funded by the UK Natural Environment Research Council (NERC) (grant NE/K006045/1) and NERC studentship. Data will be deposited in the UK Centre for Environmental Data Analysis on completion of Rebecca Brownlow’s PhD thesis

    Stable isotope evidence for late medieval (14th-15th C) origins of the eastern Baltic cod (Gadus morhua) fishery

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    Although recent historical ecology studies have extended quantitative knowledge of eastern Baltic cod (Gadus morhua) exploitation back as far as the 16th century, the historical origin of the modern fishery remains obscure. Widespread archaeological evidence for cod consumption around the eastern Baltic littoral emerges around the 13th century, three centuries before systematic documentation, but it is not clear whether this represents (1) development of a substantial eastern Baltic cod fishery, or (2) large-scale importation of preserved cod from elsewhere. To distinguish between these hypotheses we use stable carbon and nitrogen isotope analysis to determine likely catch regions of 74 cod vertebrae and cleithra from 19 Baltic archaeological sites dated from the 8th to the 16th centuries. δ¹³C and δ¹⁵N signatures for six possible catch regions were established using a larger sample of archaeological cod cranial bones (n = 249). The data strongly support the second hypothesis, revealing widespread importation of cod during the 13th to 14th centuries, most of it probably from Arctic Norway. By the 15th century, however, eastern Baltic cod dominate within our sample, indicating the development of a substantial late medieval fishery. Potential human impact on cod stocks in the eastern Baltic must thus be taken into account for at least the last 600 years.The research was funded by the Leverhulme Trust (grant no. F/00 224/S), the History of Marine Animal Populations project (supported by the Alfred P. Sloan Foundation) and the McDonald Institute for Archaeological Research

    Microstructural evolution in solution heat treatment of gas- atomised Al alloy (7075) powder for cold spray

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    Cold gas dynamic spray is being explored as a repair technique for high-value metallic components, given its potential to produce pore and oxide-free deposits of between several micrometers and several millimeters thick with good levels of adhesion and mechanical strength. However, feedstock powders for cold spray experience rapid solidification if manufactured by gas atomization and hence can exhibit non-equilibrium microstructures and localized segregation of alloying elements. Here, we used sealed quartz tube solution heat treatment of a precipitation hardenable 7075 aluminum alloy feedstock to yield a consistent and homogeneous powder phase composition and microstructure prior to cold spraying, aiming for a more controllable heat treatment response of the cold spray deposits. It was shown that the dendritic microstructure and solute segregation in the gas-atomized powders were altered, such that the heat-treated powder exhibits a homogeneous distribution of solute atoms. Micro-indentation testing revealed that the heat-treated powder exhibited a mean hardness decrease of nearly 25% compared to the as received powder. Deformation of the powder particles was enhanced by heat treatment, resulting in an improved coating with higher thickness (* 300 lm compared to * 40 um for untreated feedstock). Improved particle–substrate bonding was evidenced by formation of jets at the particle boundaries

    B->eta(') Form Factors in QCD

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    We calculate the semileptonic form factors f+Bη(q2)f_+^{B\to \eta}(q^2) and f+Bη(q2)f_+^{B\to \eta'}(q^2) from QCD sum rules on the light-cone (LCSRs), to NLO in QCD, and for small to moderate q^2, 0q216GeV20\leq q^2\leq 16 {\rm GeV}^2. We include in particular the so-called singlet contribution, i.e.\ weak annihilation of the B meson with the emission of two gluons which, thanks to the U(1)A_{\rm A} anomaly, couple directly to \etap. This effect is included to leading-twist accuracy. This contribution has been neglected in previous calculations of the form factors from LCSRs. We find that the singlet contribution to f+Bηf_+^{B\to \eta'} can be up to 20%, while that to f+Bηf_+^{B\to \eta} is, as expected, much smaller and below 3%. We also suggest to measure the ratio B(Bηeν)/B(Bηeν){\cal B}(B\to\eta' e \nu)/{\cal B}(B\to \eta e \nu) to better constrain the size of the singlet contribution.Comment: 21 pages; version to appear in JHE
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