997 resultados para McPherran, Edgar W.
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Book review of Atlas of Anatomy by Patrick W. Tank and Thomas R. Gest
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In this paper we present oscillator strengths and transition probabilities for W xlv transitions between levels arising from configurations 3d104s2,4p2,4d2, 3d104k4l (k = s,p,d,f and l = p,d,f), 3d94s24l (l = p,d,f) and 3d94s4p2. The model used to calculate these contained all configurations which can be constructed from the available orbitals (up to n = 4), with either a 3d10 or 3d9 core. The calculations were performed with the configuration interaction CIV3 program with the inclusion of relativistic effects achieved through the use of the Breit-Pauli approximation. We compare our ab initio energy levels, oscillator strengths and transition rates with other experimental and theoretical values available in the literature. There is generally good agreement when only levels with 3d10 cores are considered. The literature is sparse for levels in which the 3d-subshell is opened: for the majority of the fine-structure lines considered, there is either no comparison data available or substantial differences are found. This paper also investigates how the inclusion of relativistic effects can result in a significant redistribution of the oscillator strength from the LS calculations.
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Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms.
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Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - http://www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.
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Experimental results on relativistic surface HHG at a repetition rate of 10 Hz are presented. Average powers in the 10?W range are generated in the spectral range of 51 to 26 nm (24-48 eV). The surface harmonic radiation is produced by focusing the second-harmonic of a high-power laser onto a rotating glass surface to moderately relativistic intensities of 3×10 19Wcm ?2. The harmonic emission exhibits a divergence of 26 mrad. Together with absolute photon numbers recorded by a calibrated spectrometer, this allows for the determination of the extreme ultraviolet (XUV) yield. The pulse energies of individual harmonics are reaching up to the μJ level, equivalent to an efficiency of 10 ?5. The capability of producing stable and intense high-harmonic radiation from relativistic surface plasmas may facilitate experiments on nonlinear ionization or the seeding of free-electron lasers. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
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Aluminium targets were irradiated with 92 eV radiation from FLASH Free Electron Laser at DESY at intensities up to 10(17)W/cm(2) by focussing the beam on target down to a spot size of similar to 1 mu m by means of a parabolic mirror. High resolution XUV spectroscopy was used to identify aluminium emission from complex hole-states. Simulations carried out with the MARIA code show that the emission characterizes the electron heating in the transition phase solid-atomic. The analysis allows constructing a simple model of electron heating via Auger electrons.
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Adsorption of 0.5 monolayer of N adatoms on W{100} results in a sharp (root 2 X root 2)R45 degrees LEED pattern. The only previous quantitative LEED study of this system gave a simple overlayer model with a Pendry R-factor of 0.55. An exhaustive search has been made of possible structures, including a novel vacancy reconstruction, displacive reconstructions and underlayer adsorption. From this work a new overlayer structure is derived with an R(p) value of 0.22, displaying a considerable buckling of 0.27 +/- 0.05 Angstrom within the second W layer and consequently involving large changes in the interlayer spacings of the surface. The N adatom is pseudo-five-fold coordinated to the W surface, bonding to a second-layer W atom with a nearest-neighbour bond length of 2.13 Angstrom and with the four next-nearest-neighbour W atoms in the surface plane at 2.27 Angstrom. The structure does not resolve the work function anomaly observed on this surface.
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Deposition of 0.5 ML of Cu on W(100) leads to the formation of a sharp c(2 x 2) structure when the surface is annealed at 800 K. A LEED intensity analysis reveals that the Cu atoms are adsorbed displacively into W sites, forming an ordered 2D surface alloy. Due to the lattice mismatch between copper and tungsten, a substantial buckling of the first layer of the alloy is also observed. The clean, bulk terminated W(100) surface is only just stable relative to the c(2 x 2) vacancy covered W(100) surface. This relative stability of the vacancy structure explains the driving force behind the formation of this alloy.