454 research outputs found

    Projections for measuring the size of the solar core with neutrino-electron scattering

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    We quantify the amount of data needed in order to measure the size and position of the 8^8B neutrino production region within the solar core, for experiments looking at elastic scattering between electrons and solar neutrinos. The directions of the electrons immediately after scattering are strongly correlated with the incident directions of the neutrinos, however this is degraded significantly by the subsequent scattering of these electrons in the detector medium. We generate distributions of such electrons for different neutrino production profiles, and use a maximum likelihood analysis to make projections for future experimental sensitivity. We find that with approximately 20 years worth of data the Super Kamiokande experiment could constrain the central radius of the shell in which 8^8B neutrinos are produced to be less than 0.22 of the total solar radius at 95% confidence.Comment: 5 pages, 2 figures. Matches version accepted to PRL. Improved 2D analysis and results discussio

    Groundwater dynamics in coastal gravel barriers backed by freshwater lagoons and the potential for saline intrusion: Two cases from the UK

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    “NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Marine Systems. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Marine Systems, [VOL 123, (01.08.13)] DOI 10.1016/j.jmarsys.2013.04.004". The full text is under embargo until 01.08.15

    Genome-wide analyses identify SCN5A as a susceptibility locus for premature atrial contraction frequency.

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    Premature atrial contractions (PACs) are frequently observed on electrocardiograms and are associated with increased risks of atrial fibrillation (AF), stroke, and mortality. In this study, we aimed to identify genetic susceptibility loci for PAC frequency. We performed a genome-wide association study meta-analysis with PAC frequency obtained from ambulatory cardiac monitoring in 4,831 individuals of European ancestry. We identified a genome-wide significant locus at the SCN5A gene. The lead variant, rs7373862, located in an intron of SCN5A, was associated with an increase of 0.12 [95% CI 0.08-0.16] standard deviations of the normalized PAC frequency per risk allele. Among genetic variants previously associated with AF, there was a significant enrichment in concordance of effect for PAC frequency (n = 73/106, p = 5.1 × 10-5). However, several AF risk loci, including PITX2, were not associated with PAC frequency. These findings suggest the existence of both shared and distinct genetic mechanisms for PAC frequency and AF

    Improving Crop Yield and Nutrient Use Efficiency via Biofertilization - A Global Meta-analysis

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    The application of microbial inoculants (biofertilizers) is a promising technology for future sustainable farming systems in view of rapidly decreasing phosphorus stocks and the need to more efficiently use available nitrogen (N). Various microbial taxa are currently used as biofertilizers, based on their capacity to access nutrients from fertilizers and soil stocks, to fix atmospheric nitrogen, to improve water uptake or to act as biocontrol agents. Despite the existence of a considerable knowledge on effects of specific taxa of biofertilizers, a comprehensive quantitative assessment of the performance of biofertilizers with different traits such as phosphorus solubilization and N fixation applied to various crops at a global scale is missing. We conducted a meta-analysis to quantify benefits of biofertilizers in terms of yield increase, nitrogen and phosphorus use efficiency, based on 171 peer reviewed publications that met eligibility criteria. Major findings are: (i) the superiority of biofertilizer performance in dry climates over other climatic regions (yield response: dry climate +20.0 ± 1.7%, tropical climate +14.9 ± 1.2%, oceanic climate +10.0 ± 3.7%, continental climate +8.5 ± 2.4%); (ii) meta-regression analyses revealed that yield response due to biofertilizer application was generally small at low soil P levels; efficacy increased along higher soil P levels in the order arbuscular mycorrhizal fungi (AMF), P solubilizers, and N fixers; (iii) meta-regressions showed that the success of inoculation with AMF was greater at low organic matter content and at neutral pH. Our comprehensive analysis provides a basis and guidance for proper choice and application of biofertilizers

    The tomato cis– prenyltransferase gene family

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96709/1/tpj12063-sup-0004-FigureS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96709/2/tpj12063-sup-0005-FigureS5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96709/3/tpj12063-sup-0002-FigureS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96709/4/tpj12063-sup-0003-FigureS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96709/5/tpj12063-sup-0001-FigureS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96709/6/tpj12063.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96709/7/tpj12063-sup-0006-TableS1.pd

    The worldwide marine radiocarbon reservoir effect: definitions, mechanisms, and prospects

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    When a carbon reservoir has a lower radiocarbon content than the atmosphere, this is referred to as a reservoir effect. This is expressed as an offset between the radiocarbon ages of samples from the two reservoirs at a single point in time. The marine reservoir effect (MRE) has been a major concern in the radiocarbon community, as it introduces an additional source of error that is often difficult to accurately quantify. For this reason, researchers are often reluctant to date marine material where they have another option. The influence of this phenomenon makes the study of the MRE important for a broad range of applications. The advent of Accelerator Mass Spectrometry (AMS) has reduced sample size requirements and increased measurement precision, in turn increasing the number of studies seeking to measure marine samples. These studies rely on overcoming the influence of the MRE on marine radiocarbon dates through the worldwide quantification of the local parameter ΔR, that is, the local variation from the global average MRE. Furthermore, the strong dependence on ocean dynamics makes the MRE a useful indicator for changes in oceanic circulation, carbon exchange between reservoirs, and the fate of atmospheric CO2, all of which impact Earth's climate. This article explores data from the Marine Reservoir Database and reviews the place of natural radiocarbon in oceanic records, focusing on key questions (e.g., changes in ocean dynamics) that have been answered by MRE studies and on their application to different subjects
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