91 research outputs found

    Multiparameter radar observations of time evolution of convective storms: evaluation of water budgets and latent heating rates

    Get PDF
    Includes bibliographical references (page 1109).One advantage of dual-polarization radars is the ability to differentiate between water and ice phases in storms. The application of difference reflectivity (ZDP) in the analysis of mixed-phase precipitation is presented. Here, ZDP analysis is used to obtain the fraction of water and ice in mixed-phase precipitation. The techniques developed are applied to data collected on 9 August 1991 during the Convection and Precipitation Electrification experiment. Time series of storm total liquid and ice water contents are computed. The liquid and ice water contents are used in a water budget equation to obtain the net latent heating of the convective storm. It is shown that the latent heating profile shows good correlation with the updraft and electric field increases in the time evolution of the storm

    Post Weaning Management of Heifer Calves Impacts ADG and Feed Efficiency as Pregnant Heifers

    Get PDF
    Replacement heifers were developed on cornstalks (Exp. 1, 2, and 3), dry lot (Exp. 1 and 2), or winter range (Exp. 3). In Exp. 1, pregnant heifers were individually fed during mid to late gestation. Heifers developed on cornstalks were more feed efficient than heifers developed in a dry lot. In Exp. 2 and 3, pregnant heifers grazed cornstalks during mid to late gestation. Heifers developed on cornstalks gained more and were more efficient, especially compared to heifers developed in a dry lot. These data provide evidence of an adaptive response to grazing low quality forages and may be beneficial in the critical period leading up to the first calving season

    Molecular simulation of hydrogen storage and transport in cellulose

    Get PDF
    In this work we describe a computational workflow to model the sorption and transport of molecular hydrogen in cellulose frameworks. The work demonstrates the value of the molecular dynamics code, DL_POLY and Monte Carlo code, DL_MONTE sharing common input formats to enhance the compatibility of the codes, being supported by DL_FIELD. Structures generated using cellulose-builder were processed by DL_FIELD to generate input files for DL_POLY using the OPLS_2005 force field. After relaxation in molecular dynamics, structures were used for GCMC simulations in DL_MONTE before passing back to DL_POLY to evaluate transport properties at different levels of sorption. While no hydrogen sorption was seen in pure crystalline cellulose, increasing separation between layers did allow sorption. When slit-pores were sufficiently wide, interactions with the cellulose led to the volumetric density of adsorbed hydrogen exceeding vacuum density at accessible partial pressures as well as allowing diffusion through the system. These model systems can give useful insight into the behaviour of amorphous cellulose in future simulation and experiment

    Comparison of Performance Test Results to CFD and Structural Models of Non-Contacting Finger Seals

    Get PDF
    Performance tests of non-contacting finger seal designs were conducted at 300, 700, 922 K (70, 800 and 1200 F) at pressure differentials up to 517 kPa (75 psid) and surface speeds up to 366 m/s (1200 ft/s). Room temperature, static analysis of the seal was performed. A simplified CFD model was developed to examine pressure loads within the seal. Results from the CFD model were used as input to a finite element analysis model of a six-finger segment of the non-contacting finger seal. Examination of predicted deflections of individual components of the seal gives insight into the seal behavior. Wear patterns from testing verify the pattern of radial deflection. The models are used to predict maximum pressure differential capability of the seal and compared to experimental results. The CFD model slightly under-predicts the measured leakage flow factor, but has the same trend as the measured flow factor versus pressure differential

    Effect of adding a compassion-focused intervention on emotion, eating and weight outcomes in a commercial weight management programme

    Get PDF
    This study examined whether adding a compassion-focused light touch digital intervention into a commercial multicomponent weight management programme improved eating behaviour, self-evaluation and weight-related outcomes. The compassion intervention significantly reduced binge eating symptomatology and dropout, and improved psychological adjustment and self-evaluation, but did not affect weight outcomes. Compassion, self-reassurance and reductions in shame and self-criticism mediated the effect of the intervention on reductions of binge eating symptomatology. Negative self-evaluation, binge eating symptomatology, susceptibility to hunger and eating guilt were significant predictors of dropout. Findings suggest that compassion-based digital tools may help participants better manage binge eating symptomatology and self-evaluation in weight management interventions.Slimming Worl

    Patterns of local and nonlocal water resource use across the western U.S. determined via stable isotope intercomparisons

    Get PDF
    In the western U.S., the mismatch between public water demands and natural water availability necessitates large interbasin transfers of water as well as groundwater mining of fossil aquifers. Here we identify probable situations of nonlocal water use in both space and time based on isotopic comparisons between tap waters and potential water resources within hydrologic basins. Our approach, which considers evaporative enrichment of heavy isotopes during storage and distribution, is used to determine the likelihood of local origin for 612 tap water samples collected from across the western U.S. We find that 64% of samples are isotopically distinct from precipitation falling within the local hydrologic basin, a proxy for groundwater with modern recharge, and 31% of samples are isotopically distinct from estimated surface water found within the local basin. Those samples inconsistent with local water sources, which we suggest are likely derived from water imported from other basins or extracted from fossil aquifers, are primarily clustered in southern California, the San Francisco Bay area, and central Arizona. Our isotope-based estimates of nonlocal water use are correlated with both hydrogeomorphic and socioeconomic properties of basins, suggesting that these factors exert a predictable influence on the likelihood that nonlocal waters are used to supply tap water. We use these basin properties to develop a regional model of nonlocal water resource use that predicts (r2 = 0.64) isotopically inferred patterns and allows assessment of total interbasin transfer and/or fossil aquifer extraction volumes across the western U.S.Fil: Good, Stephen P.. University of Utah; Estados UnidosFil: Kennedy, Casey D.. United States Department Of Agriculture. Agriculture Research Service; Estados UnidosFil: Stalker Jeremy C.. Jacksonville University; Estados UnidosFil: Chesson, Lesley A.. IsoForensics; Estados UnidosFil: Valenzuela, Luciano Oscar. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Sociales. Departamento de Arqueología. Laboratorio de Ecología Evolutiva Humana (Sede Quequén); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Utah; Estados UnidosFil: Beasley, Melanie M.. University of California at San Diego; Estados UnidosFil: Ehleringer, James R. University of Utah; Estados UnidosFil: Bowen, Gabriel J.. University of Utah; Estados Unido

    Novel AroA from Pseudomonas putida Confers Tobacco Plant with High Tolerance to Glyphosate

    Get PDF
    Glyphosate is a non-selective broad-spectrum herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, also designated as AroA), a key enzyme in the aromatic amino acid biosynthesis pathway in microorganisms and plants. Previously, we reported that a novel AroA (PpAroA1) from Pseudomonas putida had high tolerance to glyphosate, with little homology to class I or class II glyphosate-tolerant AroA. In this study, the coding sequence of PpAroA1 was optimized for tobacco. For maturation of the enzyme in chloroplast, a chloroplast transit peptide coding sequence was fused in frame with the optimized aroA gene (PparoA1optimized) at the 5′ end. The PparoA1optimized gene was introduced into the tobacco (Nicotiana tabacum L. cv. W38) genome via Agrobacterium-mediated transformation. The transformed explants were first screened in shoot induction medium containing kanamycin. Then glyphosate tolerance was assayed in putative transgenic plants and its T1 progeny. Our results show that the PpAroA1 from Pseudomonas putida can efficiently confer tobacco plants with high glyphosate tolerance. Transgenic tobacco overexpressing the PparoA1optimized gene exhibit high tolerance to glyphosate, which suggest that the novel PpAroA1 is a new and good candidate applied in transgenic crops with glyphosate tolerance in future

    Developing evidence-based ethical policies on the migration of health workers: conceptual and practical challenges

    Get PDF
    It is estimated that in 2000 almost 175 million people, or 2.9% of the world's population, were living outside their country of birth, compared to 100 million, or 1.8% of the total population, in 1995. As the global labour market strengthens, it is increasingly highly skilled professionals who are migrating. Medical practitioners and nurses represent a small proportion of highly skilled workers who migrate, but the loss of health human resources for developing countries can mean that the capacity of the health system to deliver health care equitably is compromised. However, data to support claims on both the extent and the impact of migration in developing countries is patchy and often anecdotal, based on limited databases with highly inconsistent categories of education and skills. The aim of this paper is to examine some key issues related to the international migration of health workers in order to better understand its impact and to find entry points to developing policy options with which migration can be managed. The paper is divided into six sections. In the first, the different types of migration are reviewed. Some global trends are depicted in the second section. Scarcity of data on health worker migration is one major challenge and this is addressed in section three, which reviews and discusses different data sources. The consequences of health worker migration and the financial flows associated with it are presented in section four and five, respectively. To illustrate the main issues addressed in the previous sections, a case study based mainly on the United Kingdom is presented in section six. This section includes a discussion on policies and ends by addressing the policy options from a broader perspective

    Patterns of nucleotide diversity at the regions encompassing the Drosophila insulin-like peptide (dilp) genes: demography vs positive selection in Drosophila melanogaster.

    Get PDF
    In Drosophila, the insulin-signaling pathway controls some life history traits, such as fertility and lifespan, and it is considered to be the main metabolic pathway involved in establishing adult body size. Several observations concerning variation in body size in the Drosophila genus are suggestive of its adaptive character. Genes encoding proteins in this pathway are, therefore, good candidates to have experienced adaptive changes and to reveal the footprint of positive selection. The Drosophila insulin-like peptides (DILPs) are the ligands that trigger the insulin-signaling cascade. In Drosophila melanogaster, there are several peptides that are structurally similar to the single mammalian insulin peptide. The footprint of recent adaptive changes on nucleotide variation can be unveiled through the analysis of polymorphism and divergence. With this aim, we have surveyed nucleotide sequence variation at the dilp1-7 genes in a natural population of D. melanogaster. The comparison of polymorphism in D. melanogaster and divergence from D. simulans at different functional classes of the dilp genes provided no evidence of adaptive protein evolution after the split of the D. melanogaster and D. simulans lineages. However, our survey of polymorphism at the dilp gene regions of D. melanogaster has provided some evidence for the action of positive selection at or near these genes. The regions encompassing the dilp1-4 genes and the dilp6 gene stand out as likely affected by recent adaptive events
    corecore