147 resultados para Southern Spectrophotometric Standards


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We report the detection of a 0.6 MJ extrasolar planet by WASP-South, WASP-25b, transiting its solar-type host star every 3.76 d. A simultaneous analysis of the WASP, FTS and Euler photometry and CORALIE spectroscopy yields a planet of Rp= 1.22 RJ and Mp= 0.58 MJ around a slightly metal-poor solar-type host star, [Fe/H]=- 0.05 ± 0.10, of R*= 0.92 Rsun and M*= 1.00 Msun. WASP-25b is found to have a density of ?p= 0.32 ?J, a low value for a sub-Jupiter mass planet. We investigate the relationship of planetary radius to planetary equilibrium temperature and host star metallicity for transiting exoplanets with a similar mass to WASP-25b, finding that these two parameters explain the radii of most low-mass planets well.

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Despite major improvements in diagnostics and interventional therapies, cardiovascular diseases remain a major health care and socio-economic burden both in western and developing countries, in which this burden is increasing in close correlation to economic growth. Health authorities and the general population have started to recognize that the fight against these diseases can only be won if their burden is faced by increasing our investment on interventions in lifestyle changes and prevention. There is an overwhelming evidence of the efficacy of secondary prevention initiatives including cardiac rehabilitation in terms of reduction in morbidity and mortality. However, secondary prevention is still too poorly implemented in clinical practice, often only on selected populations and over a limited period of time. The development of systematic and full comprehensive preventive programmes is warranted, integrated in the organization of national health systems. Furthermore, systematic monitoring of the process of delivery and outcomes is a necessity. Cardiology and secondary prevention, including cardiac rehabilitation, have evolved almost independently of each other and although each makes a unique contribution it is now time to join forces under the banner of preventive cardiology and create a comprehensive model that optimizes long term outcomes for patients and reduces the future burden on health care services. These are the aims that the Cardiac Rehabilitation Section of the European Association for Cardiovascular Prevention & Rehabilitation has foreseen to promote secondary preventive cardiology in clinical practice.

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A new approach to spectroscopy of laser induced proton beams using radiochromic film (RCF) is presented. This approach allows primary standards of absorbed dose-to-water as used in radiotherapy to be transferred to the calibration of GafChromic HD-810 and EBT in a 29 MeV proton beam from the Birmingham cyclotron. These films were then irradiated in a common stack configuration using the TARANIS Nd:Glass multi-terawatt laser at Queens University Belfast, which can accelerate protons to 10-12 MeV, and a depth-dose curve was measured from a collimated beam. Previous work characterizing the relative effectiveness (RE) of GafChromic film as a function of energy was implemented into Monte Carlo depth-dose curves using FLUKA. A Bragg peak (BP) "library" for proton energies 0-15 MeV was generated, both with and without the RE function. These depth-response curves were iteratively summed in a FORTRAN routine to solve for the measured RCF depth-dose using a simple direct search algorithm. By comparing resultant spectra with both BP libraries, it was found that the effect of including the RE function accounted for an increase in the total number of protons by about 50%. To account for the energy loss due to a 20 mu m aluminum filter in front of the film stack, FLUKA was used to create a matrix containing the energy loss transformations for each individual energy bin. Multiplication by the pseudo-inverse of this matrix resulted in "up-shifting" protons to higher energies. Applying this correction to two laser shots gave further increases in the total number of protons, N of 31% and 56%. Failure to consider the relative response of RCF to lower proton energies and neglecting energy losses in a stack filter foil can potentially lead to significant underestimates of the total number of protons in RCF spectroscopy of the low energy protons produced by laser ablation of thin targets.

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Like many of the world's subtropical regions, southern Africa is highly sensitive to changes in the earth's climate system, but a dearth of reliable palaeoenvironmental records means that relatively little is known about how regional environments have been affected over centennial to multi-millennial timescales. To a large extent this sensitivity is a function of the position of these regions at the interface between temperate and tropical circulation systems. The resulting seasonality and irregularity of rainfall have limited the development of suitable archives, such as lakes and wetlands, for the preservation of palaeoenvironmental proxies.

This paper reviews and evaluates the value of rock hyrax middens as novel palaeoenvironmental archives in southern Africa. Considered are (1) the contemporary taxonomy, distribution and ecology of hyraxes, (2) the mechanisms of hyrax midden development, their physical and chemical structure, rates of accumulation and age; and (3) the palaeoenvironmental proxies preserved within hyrax middens, including fossil pollen, stable isotopes and biomarkers. The interpretive constraints and opportunities offered by these various midden characteristics are assessed with a view to demonstrating the potential of these deposits, widespread as they are through arid and semi-arid southern Africa, in providing a more detailed and chronologically resolved view of late Quaternary palaeoenvironments across the subcontinent. (C) 2012 Elsevier Ltd. All rights reserved.

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Public health policy for arsenic needs to better reflect the ability to detect the risk(s).

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Paddy rice has been likened to nictiana sp in its ability to scavenge cadmium (Cd) from soil, whereas arsenic (As) accumulation is commonly an order of magnitude higher than in other cereal crops. In areas such as those found in parts of Hunan province in south central China, base-metal mining activities and rice farming coexist. Therefore there is a considerable likelihood that lead (Pb), in addition to Cd and As, will accumulate in rice grown in parts of this region above levels suitable for human consumption. To test this hypothesis, a widespread provincial survey of rice from mine spoilt paddies (n = 100), in addition to a follow-up market grain survey (n = 122) conducted in mine impacted areas was undertaken to determine the safety of local rice supply networks. Furthermore, a specific Cd, As, and Pb biogeochemical survey of paddy soil and rice was conducted within southern China, targeting sites impacted by mining of varying intensities to calibrate rice metal(loid) transfer models and transfer factors that can be used to predict tissue loading. Results revealed a number of highly significant correlations between shoot, husk, bran, and endosperm rice tissue fractions and that rice from mining areas was enriched in Cd, As, and Pb. Sixty-five, 50, and 34% of all the mine-impacted field rice was predicted to fail national food standards for Cd, As, and Pb, respectively. Although, not as elevated as the grains from the mine-impacted field survey, it was demonstrated that metal(loid) tainted rice was entering food supply chains intended for direct human consumption.

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Under EU legislation, total arsenic levels in drinking water should not exceed 10 microg l(-1), while in the US this figure is set at 10 microg l(-1) inorganic arsenic. All rice milk samples analysed in a supermarket survey (n = 19) would fail the EU limit with up to 3 times this concentration recorded, while out of the subset that had arsenic species determined (n = 15), 80% had inorganic arsenic levels above 10 microg l(-1), with the remaining 3 samples approaching this value. It is a point for discussion whether rice milk is seen as a water substitute or as a food, there are no EU or US food standards highlighting the disparity between water and food regulations in this respect.

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To ascertain the response of the southern Greenland Ice Sheet (GIS) to a boreal summer climate warmer than at present, we explored whether southern Greenland was deglaciated during the Last Interglacial (LIG), using the Sr-Nd-Pb isotope ratios of silt-sized sediment discharged from southern Greenland. Our isotope data indicate that no single southern Greenland geologic terrane was completely deglaciated during the LIG, similar to the Holocene. Differences in sediment sources during the LIG relative to the early Holocene denote, however, greater southern GIS retreat during the LIG. These results allow the evaluation of a suite of GIS models and are consistent with a GIS contribution of 1.6 to 2.2 meters to the =4-meter LIG sea-level highstand, requiring a significant sea-level contribution from the Antarctic Ice Sheet.

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This study presents phylogenetic molecular data of the Chilean species of Orestias to propose an allopatric divergence hypothesis and phylogeographic evidence that suggests the relevance of abiotic factors in promoting population divergence in this complex. The results reveal that diversification is still ongoing, e.g. in the Ascotán salt pan, where populations of Orestias ascotanensis restricted to individual freshwater springs exhibit strong genetic differentiation, reflecting putative independent evolutionary units. Diversification of Orestias in the southern Altiplano may be linked to historical vicariant events and contemporary variation in water level; these processes may have affected the populations from the Plio-Pleistocene until the present.