294 research outputs found

    Downscale cascades in tracer transport test cases: an intercomparison of the dynamical cores in the Community Atmosphere Model CAM5

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    The accurate modeling of cascades to unresolved scales is an important part of the tracer transport component of dynamical cores of weather and climate models. This paper aims to investigate the ability of the advection schemes in the National Center for Atmospheric Research's Community Atmosphere Model version 5 (CAM5) to model this cascade. In order to quantify the effects of the different advection schemes in CAM5, four two-dimensional tracer transport test cases are presented. Three of the tests stretch the tracer below the scale of coarse resolution grids to ensure the downscale cascade of tracer variance. These results are compared with a high resolution reference solution, which is simulated on a resolution fine enough to resolve the tracer during the test. The fourth test has two separate flow cells, and is designed so that any tracer in the western hemisphere should not pass into the eastern hemisphere. This is to test whether the diffusion in transport schemes, often in the form of explicit hyper-diffusion terms or implicit through monotonic limiters, contains unphysical mixing. <br><br> An intercomparison of three of the dynamical cores of the National Center for Atmospheric Research's Community Atmosphere Model version 5 is performed. The results show that the finite-volume (CAM-FV) and spectral element (CAM-SE) dynamical cores model the downscale cascade of tracer variance better than the semi-Lagrangian transport scheme of the Eulerian spectral transform core (CAM-EUL). Each scheme tested produces unphysical mass in the eastern hemisphere of the separate cells test

    CREEP AND CORROSION PROPERTIES OF ZIRCALOY-2 IN STEAM AT 750 F

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    Test equipment to determine the creep properties of Zircaloy-2 in a 750 deg F 500-psi steam atmosphere was designed and constructed. Duplicate tests were performed at stresses to produce failure in approximately 1, 10, 100, and 1000 hr. A comparison between these data and data obtained in vacuum-test equipment showed that a corrosive test atmosphere does not alter ductility or failure times appreciably. (auth

    Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

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    Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100–400 nm) and, in particular, vacuum ultraviolet (VUV, 10–200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH2O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H2O2) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O2•−) and hydroxyl radicals (•OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed

    HIGH-TEMPERATURE OXIDATION RESISTANCE OF THIN IRON-CHROMIUM-ALUMINUM ALLOY SHEET

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    S>The oxidation resistance of thin sheets of Fe - 28 wt. % Cr - 2.67 to 10.0 wt. % Al alloys, nominally 0.004, 0.006, 0.008, 0.012, and 0.016 in. thick, was determined by exposure in static air for 100 hr at 2100 and 2300 deg F. A minimum of 3.67 and 9.37 wt.% Al was necessary to prevent excessive oxidation of 0.004-in. thick sheet material at 2100 and 2300 deg F, respectively. Specimens of lower Al content and greater thickness withstood oxidation attack. Oxidation of Fe - Cr - Al alloys apperars to be related to the diffusion of Al to surfaces of the sheet to form an adherent protective layer of Al/sub 2/ O/sub 3/.(auth

    A mutated dph3 gene causes sensitivity of Schizosaccharomyces pombe cells to cytotoxic agents

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    Dph3 is involved in diphthamide modification of the eukaryotic translation elongation factor eEF2 and in Elongator-mediated modifications of tRNAs, where a 5-methoxycarbonyl-methyl moiety is added to wobble uridines. Lack of such modifications affects protein synthesis due to inaccurate translation of mRNAs at ribosomes. We have discovered that integration of markers at the msh3 locus of Schizosaccharomyces pombe impaired the function of the nearby located dph3 gene. Such integrations rendered cells sensitive to the cytotoxic drugs hydroxyurea and methyl methanesulfonate. We constructed dph3 and msh3 strains with mutated ATG start codons (ATGmut), which allowed investigating drug sensitivity without potential interference by marker insertions. The dph3- ATGmut and a dph3::loxP-ura4-loxM gene disruption strain, but not msh3-ATGmut, turned out to be sensitive to hydroxyurea and methyl methanesulfonate, likewise the strains with cassettes integrated at the msh3 locus. The fungicide sordarin, which inhibits diphthamide modified eEF2 of Saccharomyces cerevisiae, barely affected survival of wild type and msh3Δ S. pombe cells, while the dph3Δ mutant was sensitive. The msh3-ATG mutation, but not dph3Δ or the dph3-ATG mutation caused a defect in mating-type switching, indicating that the ura4 marker at the dph3 locus did not interfere with Msh3 function. We conclude that Dph3 is required for cellular resistance to the fungicide sordarin and to the cytotoxic drugs hydroxyurea and methyl methanesulfonate. This is likely mediated by efficient translation of proteins in response to DNA damage and replication stress

    Two novel energy crops: Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L. - State of knowledge

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    Current global temperature increases resulting from human activity threaten many ecosystems and societies, and have led to international and national policy commitments that aim to reduce greenhouse gas emissions. Bioenergy crops provide one means of reducing greenhouse gas emissions from energy production and two novel crops that could be used for this purpose are Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L. This research examined the existing scientific literature available on both crops through a systematic review. The data were collated according to the agronomy, uses, and environmental benefits of each crop. Possible challenges were associated with high initial planting costs, low yields in low rainfall areas, and for Sida hermaphrodita, vulnerability to Sclerotinia sclerotiorum. However, under appropriate environmental conditions, both crops were found to provide large yields over sustained periods of time with relatively low levels of management and could be used to produce large energy surpluses, either through direct combustion or biogas production. Other potential uses included fodder, fibre, and pharmaceutical uses. Environmental benefits included the potential for phytoremediation, and improvements to soil health, biodiversity, and pollination. The review also demonstrated that environmental benefits, such as pollination, soil health, and water quality benefits could be obtained from the use of Sida hermaphrodita and Silphium perfoliatum relative to existing bioenergy crops such as maize, whilst at the same time reducing the greenhouse gas emissions associated with energy production. Future research should examine the long-term implications of using Sida hermaphrodita and Silphium perfoliatum as well as improve knowledge on how to integrate them successfully within existing farming systems and supply chains

    Physics–Dynamics Coupling in weather, climate and Earth system models: Challenges and recent progress

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    This is the final version. Available from American Meteorological Society via the DOI in this record.Numerical weather, climate, or Earth system models involve the coupling of components. At a broad level, these components can be classified as the resolved fluid dynamics, unresolved fluid dynamical aspects (i.e., those represented by physical parameterizations such as subgrid-scale mixing), and nonfluid dynamical aspects such as radiation and microphysical processes. Typically, each component is developed, at least initially, independently. Once development is mature, the components are coupled to deliver a model of the required complexity. The implementation of the coupling can have a significant impact on the model. As the error associated with each component decreases, the errors introduced by the coupling will eventually dominate. Hence, any improvement in one of the components is unlikely to improve the performance of the overall system. The challenges associated with combining the components to create a coherent model are here termed physics–dynamics coupling. The issue goes beyond the coupling between the parameterizations and the resolved fluid dynamics. This paper highlights recent progress and some of the current challenges. It focuses on three objectives: to illustrate the phenomenology of the coupling problem with references to examples in the literature, to show how the problem can be analyzed, and to create awareness of the issue across the disciplines and specializations. The topics addressed are different ways of advancing full models in time, approaches to understanding the role of the coupling and evaluation of approaches, coupling ocean and atmosphere models, thermodynamic compatibility between model components, and emerging issues such as those that arise as model resolutions increase and/or models use variable resolutions.Natural Environment Research Council (NERC)National Science FoundationDepartment of Energy Office of Biological and Environmental ResearchPacific Northwest National Laboratory (PNNL)DOE Office of Scienc

    Impact of gastroesophageal reflux disease on patients' daily lives: a European observational study in the primary care setting

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    <p>Abstract</p> <p>Background</p> <p>The impact of gastroesophageal reflux disease (GERD) on the daily lives of patients managed in primary care is not well known. We report the burden of GERD in a large population of patients managed in primary care, in terms of symptoms and impact on patients' daily lives.</p> <p>Methods</p> <p>RANGE (<it>R</it>etrospective <it>AN</it>alysis of <it>GE</it>RD) was an observational study that was conducted at 134 primary care sites across six European countries. All adult subjects who had consulted their primary care physician (PCP) during a 4-month identification period were screened retrospectively and those consulting at least once for GERD-related reasons were identified. From this population, a random sample of patients was selected to enter the study and attended a follow-up appointment, during which the Reflux Disease Questionnaire (RDQ), the GERD Impact Scale (GIS) and an extra-esophageal symptoms questionnaire were self-administered. Based on medical records, data were collected on demographics, history of GERD, its diagnostic work-up and therapy.</p> <p>Results</p> <p>Over the 4-month identification period, 373,610 subjects consulted their PCP and 12,815 (3.4%) did so for GERD-related reasons. From 2678 patients interviewed (approximately 75% of whom reported taking medication for GERD symptoms), symptom recurrence following a period of remission was the most common reason for consultation (35%). At the follow-up visit, with regard to RDQ items (score range 0–5, where high score = worse status), mean Heartburn dimension scores ranged from 0.8 (Sweden) to 1.2 (UK) and mean Regurgitation dimension scores ranged from 1.0 (Norway) to 1.4 (Germany). Mean overall GIS scores (range 1–4, where low score = worse status) ranged from 3.3 (Germany) to 3.5 (Spain). With regard to extra-esophageal symptoms, sleep disturbance was common in all countries in terms of both frequency and intensity.</p> <p>Conclusion</p> <p>In this large European observational study, GERD was associated with a substantial impact on the daily lives of affected individuals managed in the primary care setting.</p
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