542 research outputs found

    The exposure history of the Apollo 16 site: An assessment based on methane and hydrolysable carbon

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    Nineteen soils from eight stations at the Apollo 16 landing site have been analyzed for methane and hydrolysable carbon. These results, in conjunction with published data from photogeology, bulk chemistry, rare gases, primordial and cosmogenic radionuclides, and agglutinate abundances have been interpreted in terms of differing contributions from three components-North and South Ray Crater ejecta and Cayley Plains material

    Movement-based subgrouping in low back pain: synergy and divergence in approaches

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    Background Classification systems for low back pain (LBP) aim to guide treatment decisions. In physiotherapy, there are five classification schemes for LBP which consider responses to clinical movement examination. Little is known of the relationship between the schemes

    Cosmogenic C-14 in Antarctic and non-Antarctic meteorites and lunar samples

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    We were able to develop measurements of C-14 in meteorites as a useful tool for estimates of terrestrial age. Prior to this accomplishment, only a few measurements of C-14 terrestrial ages had been made. The sample sizes were larger, and there had been no systematic study of the various parameters affecting production of C-14, such as depth dependence, and the production cross sections for C-14 from spallation amounted to a few data points. Presently, C-14 ages are an accepted terrestrial age estimate in the meteorite community, whereas before this work the few data available were difficult to interpret. We have obtained terrestrial ages not only on groups of meteorites from different geographic areas but also information on unique meteorites from particularly interesting groups, such as meteorites originating from the Moon, or SNC meteorites, which many researchers believe are derived from Mars

    Solar control of Southwest monsoon on centennial timescales

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    Solar forcing is proposed to be a major governing factor for the southwest monsoon (SWM) strength during the Holocene. The southeastern Arabian Sea is significantly affected by monsoon run-off and is an ideal testing ground. We analysed stable oxygen isotopic composition (δ18O) of three species of planktonic foraminifera (Globigerinoides ruber, Gs. sacculifer and Globarotalia menardii) with high time-resolution (~50 yrs) in a sediment core raised from the region, and documented past variations in SWM precipitation. High-resolution isotopic and spectral analyses show that solar forcing indeed played a major role in governing the past variations in SWM precipitation on centennial timescales

    Radio-Frequency Measurements of Coherent Transition and Cherenkov Radiation: Implications for High-Energy Neutrino Detection

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    We report on measurements of 11-18 cm wavelength radio emission from interactions of 15.2 MeV pulsed electron bunches at the Argonne Wakefield Accelerator. The electrons were observed both in a configuration where they produced primarily transition radiation from an aluminum foil, and in a configuration designed for the electrons to produce Cherenkov radiation in a silica sand target. Our aim was to emulate the large electron excess expected to develop during an electromagnetic cascade initiated by an ultra high-energy particle. Such charge asymmetries are predicted to produce strong coherent radio pulses, which are the basis for several experiments to detect high-energy neutrinos from the showers they induce in Antarctic ice and in the lunar regolith. We detected coherent emission which we attribute both to transition and possibly Cherenkov radiation at different levels depending on the experimental conditions. We discuss implications for experiments relying on radio emission for detection of electromagnetic cascades produced by ultra high-energy neutrinos.Comment: updated figure 10; fixed typo in equation 2.2; accepted by PR

    A randomised clinical trial of a comprehensive exercise program for chronic whiplash: trial protocol

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    Background: Whiplash is the most common injury following a motor vehicle accident. Approximately 60% of people suffer persistent pain and disability six months post injury. Two forms of exercise; specific motor relearning exercises and graded activity, have been found to be effective treatments for this condition. Although the effect sizes for these exercise programs, individually, are modest, pilot data suggest much larger effects on pain and disability are achieved when these two treatments are combined. The aim of this study is to investigate the effectiveness and cost-effectiveness of this comprehensive exercise approach for chronic whiplash
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