631 research outputs found

    Exposure History of Lunar Meteorites Queen Alexandra Range 93069 and 94269

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    Cosmic-ray produced C-14 (t(sub 1/2) = 5730 years), 36Cl (3.01 x 10(exp 5 years), Al-26 (7.05 x 10(exp 5 years), and Be-10 (1.5 x 10(exp 6 years) in the recently discovered lunar meteorites Queen Alexandra Range 93069 (QUE 93069) and 94269 (QUE 94269) were measured by accelerator mass spectrometry. The abundance pattern of these four cosmogenic radionuclides and of noble gases indicates QUE 93069 and QUE 94269 were a paired fall and were exposed to cosmic rays near the surface of the Moon for at least several hundred million years before ejection. After the meteorite was launched from the Moon, where it had resided at a depth of 65-80 g/cm square, it experienced a short transition time, approximately 20-50 ka, before colliding with the Earth. The terrestrial age of the meteorite is 5-10 ka. Comparison ofthe cosmogenic nuclide concentrations in QUE 93069/94269 and MAC 88104/88105 clearly shows that these meteorites were not ejected by a common event from the Moon

    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

    Exposure History of Shergottites Dar AI Gani 476/489/670/735 and Sayh AI Uhaymir 005

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    Introduction: Four basaltic shergottites, Dar al Gani (DaG) 476, 489, 670, and 735 were found in the Libyan Sahara Experimental Procedures and Results: The total recovered mass of DaG 476/489/670/735 was 6,368 g and the total recovered mass of SaU 005/008/051 was 10,359 g. 1°Be, 2aAI, 36Cl, and ~lCa measurements. We received exterior and interior chips from DaG 476, 489, and 670 in order to investigate SCR effects. "The distances between exterior and interior chips are about 30, 20, and 10-15 mm respectively. Only interior chips were obtained for DaG 735 and SaU 005. Weathering products were observed on the surface of the specimens, especially DaG 476, 489, and 670. The surfaces of DaG 735 and SaU 005 were cleaner than those of DaG 476, 489, and 670. To eliminate weathering products, each sample was etched twice with,0.2 N HNO3 solution in an ultrasonic bath for 5-15 minutes

    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 controlled trial comparing graded exercise treatment and usual physiotherapy for patients with non-specific neck pain (the GET UP neck pain trial).

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    Evidence supports exercise-based interventions for the management of neck pain, however there is little evidence of its superiority over usual physiotherapy. This study investigated the effectiveness of a group neck and upper limb exercise programme (GET) compared with usual physiotherapy (UP) for patients with non-specific neck pain. A total of 151 adult patients were randomised to either GET or UP. The primary measure was the Northwick Park Neck pain Questionnaire (NPQ) score at six weeks, six months and 12 months. Mixed modelling identified no difference in neck pain and function between patients receiving GET and those receiving UP at any follow-up time point. Both interventions resulted in modest significant and clinically important improvements on the NPQ score with a change score of around 9% between baseline and 12 months. Both GET and UP are appropriate clinical interventions for patients with non-specific neck pain, however preferences for treatment and targeted strategies to address barriers to adherence may need to be considered in order to maximise the effectiveness of these approaches

    Prescribing for the management of venous leg ulceration

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    Venous leg ulceration affects a large proportion of the elderly population and can have a profound impact on quality of life. Most patients with leg ulcers receive care from community nurses who are principally responsible for prescribing decisions in the management of venous leg ulceration. There is evidence to support the use of potable tap water for cleansing. Evidence supports the use of compression bandaging or compression hosiery for all patients with adequate arterial supply to the lower leg. There is also good evidence to support the prescription of oral pentoxifylline, preferably as an adjunct to compression or, for patients unable to tolerate compression, as a stand-alone therapy. The evidence base for dressings is less robust, but simple low-cost, low-adherent dressings are a reasonable first-line choice for under-compression

    GRADE equity guidelines 3: considering health equity in GRADE guideline development: rating the certainty of synthesized evidence

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    Objectives: The aim of this paper is to describe a conceptual framework for how to consider health equity in the Grading Recommendations Assessment and Development Evidence (GRADE) guideline development process. Study Design and Setting: Consensus-based guidance developed by the GRADE working group members and other methodologists. Results: We developed consensus-based guidance to help address health equity when rating the certainty of synthesized evidence (i.e., quality of evidence). When health inequity is determined to be a concern by stakeholders, we propose five methods for explicitly assessing health equity: (1) include health equity as an outcome; (2) consider patient-important outcomes relevant to health equity; (3) assess differences in the relative effect size of the treatment; (4) assess differences in baseline risk and the differing impacts on absolute effects; and (5) assess indirectness of evidence to disadvantaged populations and/or settings. Conclusion: The most important priority for research on health inequity and guidelines is to identify and document examples where health equity has been considered explicitly in guidelines. Although there is a weak scientific evidence base for assessing health equity, this should not discourage the explicit consideration of how guidelines and recommendations affect the most vulnerable members of society

    Cesium, iodine and tritium in NW Pacific waters - a comparison of the Fukushima impact with global fallout

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    Radionuclide impact of the Fukushima Dai-ichi nuclear power plant accident on the distribution of radionuclides in seawater of the NW Pacific Ocean is compared with global fallout from atmospheric tests of nuclear weapons. Surface and water column samples collected during the <i>Ka'imikai-o-Kanaloa</i> (<i>KOK</i>) international expedition carried out in June 2011 were analyzed for <sup>134</sup>Cs, <sup>137</sup>Cs, <sup>129</sup>I and <sup>3</sup>H. The <sup>137</sup>Cs, <sup>129</sup>I and <sup>3</sup>H levels in surface seawater offshore Fukushima varied between 0.002–3.5 Bq L<sup>−1</sup>, 0.01–0.8 μBq L<sup>−1</sup>, and 0.05–0.15 Bq L<sup>−1</sup>, respectively. At the sampling site about 40 km from the coast, where all three radionuclides were analyzed, the Fukushima impact on the levels of these three radionuclides represents an increase above the global fallout background by factors of about 1000, 50 and 3, respectively. The water column data indicate that the transport of Fukushima-derived radionuclides downward to the depth of 300 m has already occurred. The observed <sup>137</sup>Cs levels in surface waters and in the water column are compared with predictions obtained from the ocean general circulation model, which indicates that the Kuroshio Current acts as a southern boundary for the transport of the radionuclides, which have been transported from the Fukushima coast eastward in the NW Pacific Ocean. The <sup>137</sup>Cs inventory in the water column is estimated to be about 2.2 PBq, what can be regarded as a lower limit of the direct liquid discharges into the sea as the seawater sampling was carried out only in the area from 34 to 37° N, and from 142 to 147° E. About 4.6 GBq of <sup>129</sup>I was deposited in the NW Pacific Ocean, and 2.4–7 GBq of <sup>129</sup>I was directly discharged as liquid wastes into the sea offshore Fukushima. The total amount of <sup>3</sup>H released and deposited over the NW Pacific Ocean was estimated to be 0.1–0.5 PBq. These estimations depend, however, on the evaluation of the total <sup>137</sup>Cs activities released as liquid wastes directly into the sea, which should improve when more data are available. Due to a suitable residence time in the ocean, Fukushima-derived radionuclides will provide useful tracers for isotope oceanography studies on the transport of water masses during the next decades in the NW Pacific Ocean
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