4,921 research outputs found

    The 1985 and 1986 direct strike lightning data, part 1

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    Data waveforms are presented which were obtained during the 1985 and 1986 direct-strike lightning tests utilizing the NASA F-106B aircraft specially instrumented for lightning electromagnetic measurement. The aircraft was operated in the vicinity of the NASA Langley Research Center, Hampton, Virginia, in a thunderstorm environment in order to elicit lightning strikes. Electromagnetic field data and conduction currents on the aircraft were recorded for lightning

    Synthetic Mudscapes: Human Interventions in Deltaic Land Building

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    In order to defend infrastructure, economy, and settlement in Southeast Louisiana, we must construct new land to mitigate increasing risk. Links between urban environments and economic drivers have constrained the dynamic delta landscape for generations, now threatening to undermine the ecological fitness of the entire region. Static methods of measuring, controlling, and valuing land fail in an environment that is constantly in flux; change and indeterminacy are denied by traditional inhabitation. Multiple land building practices reintroduce deltaic fluctuation and strategic deposition of fertile material to form the foundations of a multi-layered defence strategy. Manufactured marshlands reduce exposure to storm surge further inland. Virtual monitoring and communication networks inform design decisions and land use becomes determined by its ecological health. Mudscapes at the threshold of land and water place new value on former wastelands. The social, economic, and ecological evolution of the region are defended by an expanded web of growing land

    A Keck/HIRES Doppler Search for Planets Orbiting Metal-Poor Dwarfs. I. Testing Giant Planet Formation and Migration Scenarios

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    We describe a high-precision Doppler search for giant planets orbiting a well-defined sample of metal-poor dwarfs in the field. This experiment constitutes a fundamental test of theoretical predictions which will help discriminate between proposed giant planet formation and migration models. We present here details on the survey as well as an overall assessment of the quality of our measurements, making use of the results for the stars that show no significant velocity variation.Comment: 25 pages, 7 figures, accepted for publication in the Astrophysical Journa

    Fermion zero modes at the boundary of superfluid 3He-B

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    Superfluid 3He-B belongs to the important special class of time-reversal invariant topological superfluids. It has Majorana fermions as edge states on the surface of bulk 3He-B. On the rough wall these fermion zero modes have finite density of states at E=0. It is possible that Lancaster experiments with a wire vibrating in 3He-B have already probed Majorana fermions living on the surface of the wire.Comment: 4 pages, no Figures, JETP Letters style, version to be published in JETP Letter

    Network meta-analysis of randomised trials of pharmacological, psychotherapeutic, exercise and collaborative care interventions for depressive symptoms in patients with coronary artery disease: Hybrid systematic review of systematic reviews protocol

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    This is the author accepted manuscriptBackground: Depression is common in patients with coronary artery disease (CAD) and is associated with poorer outcomes and higher costs. Several randomised controlled trials (RCTs) targeting depression, of various modalities (including pharmacological, psychotherapeutic and other approaches), have been conducted and summarised in pairwise meta-analytic reviews. However, no study has considered the cumulative evidence within a network, which can provide valuable indirect comparisons and information about the relative efficacy of interventions. Therefore, we will adopt a review of review methodology to develop a network meta-analysis (NMA) of depression interventions for depression in CAD. Methods: We will search relevant databases from inception for systematic reviews of RCTs of depression treatments for people with CAD, supplementing this with comprehensive searches for recent or ongoing studies. We will extract data from and summarise characteristics of individual RCTs, including participants, study characteristics, outcome measures and adverse events. Cochrane risk of bias ratings will also be extracted or if not present will be conducted by the authors. RCTs that compare depression treatments (grouped as pharmacological, psychotherapeutic, combined pharmacological/psychotherapeutic, exercise, collaborative care) to placebo, usual care, waitlist control or attention controls, or directly in head-to-head comparisons, will be included. Primary outcomes will be the change in depressive symptoms (summarised with a standardised mean difference) and treatment acceptability (treatment discontinuation: % of people who withdrew). Secondary outcomes will include change in 6-month depression outcomes, health-related quality of life (HRQoL), mortality, cardiovascular morbidity, health services use and adverse events. Secondary analyses will form further networks with individual anti-depressants and psychotherapies. We will use frequentist, random effects multivariate network meta-analysis to synthesise the evidence for depression intervention and to achieve a ranking of treatments, using Stata. Rankograms and surface under the cumulative ranking curves will be used for treatment ranking. Local and global methods will evaluate consistency. GRADE will be used to assess evidence quality for primary outcomes. Discussion: The present review will address uncertainties about the evidence in terms of depression management in CAD and may allow for a ranking of treatments, including providing important information for future research efforts

    A Simple Fragment of Cyclic Acyldepsipeptides Is Necessary and Sufficient for ClpP Activation and Antibacterial Activity

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    The development of new antibacterial agents, particularly those with unique biological targets, is essential to keep pace with the inevitable emergence of drug resistance in pathogenic bacteria. We identified the minimal structural component of the cyclic acyldepsipeptide (ADEP) antibiotics that exhibits antibacterial activity. We found that N-acyldifluorophenylalanine fragments function via the same mechanism of action as ADEPs, as evidenced by the requirement of ClpP for the fragments' antibacterial activity, the ability of fragments to activate Bacillus subtilis ClpP in vitro, and the capacity of an N-acyldifluorophenylalanine affinity matrix to capture ClpP from B. subtilis cell lysates. N-acyldifluorophenylalanine fragments are much simpler in structure than the full ADEPs and are also highly amenable to structural diversification. Thus, the stage has been set for the development of non-peptide activators of ClpP that can be used as antibacterial agents.National Science Foundation (U.S.)United States. National Institutes of Health (GM-101988

    Communications Biophysics

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    Contains reports on four research projects.National Institutes of Health (Grant 5 PO1 GM14940-05)National Aeronautics and Space Administration (Grant NGL 22-009-304)National Institutes of Health (Grant 5 TO1 GM01555-05)Boston City Hospital Purchase Order 10656B-D Electrodyne Division, Becton Dickinson and Compan

    The Effect of Body Mass on the 30-15 Intermittent Fitness Test in Rugby Union Players.

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    To A) evaluate the difference in performance of the 30-15 Intermittent Fitness Test (30-15IFT) across four squads in a professional rugby union club in the United Kingdom (UK), and B) consider body mass in the interpretation of the end velocity of the 30-15IFT (VIFT).One hundred and fourteen rugby union players completed the 30-15IFT mid- season.VIFT demonstrated small and possibly lower (ES = -0.33; 4/29/67) values in the Under 16s compared to the Under 21s, with further comparisons unclear. With body mass included as a covariate all differences were moderate to large, and very likely to almost certainly lower in the squads with lower body mass, with the exception of comparisons between Senior and Under 21 squads.The data demonstrate that there appears to be a ceiling to the VIFT attained in rugby union players which does not increase from Under 16s to Senior level. However, the associated increases in body mass with increased playing level suggest that the ability to perform high intensity running is increased with age, although not translated into greater VIFT due to the detrimental effect of body mass on change of direction. . Practitioners should be aware that VIFT is unlikely to improve, however it needs to be monitored during periods where increases in body mass are evident
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