2,819 research outputs found

    Why nanoprojectiles work differently than macroimpactors: The role of plastic flow

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    Atomistic simulation data on crater formation due to the hypervelocity impact of nanoprojectiles of up to 55 nm diameter and with targets containing up to 10^10 atoms are compared to available experimental data on micron-, mm-, and cm-sized projectiles. We show that previous scaling laws do not hold in the nanoregime and outline the reasons: within our simulations we observe that the cratering mechanism changes, going from the smallest to the largest simulated scales, from an evaporative regime to a regime where melt and plastic flow dominate, as is expected in larger microscale experiments. The importance of the strain-rate dependence of strength and of dislocation production and motion are discussed.Fil: Anders, Christian. Universitat Kaiserslautern; AlemaniaFil: Bringa, Eduardo Marcial. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Ziegenhain, Gerolf. Universitat Kaiserslautern; AlemaniaFil: Graham, Giles A.. Natural History Museum; Reino UnidoFil: Hansen, J. Freddy. Lawrence Livermore National Laboratory; Estados UnidosFil: Park, Nigel. No especifíca;Fil: Teslich, Nick E.. Lawrence Livermore National Laboratory; Estados UnidosFil: Urbassek, Herbert M.. Universitat Kaiserslautern; Alemani

    Historical and Projected Municipal and Industrial Water Usage in Utah 1960-2020

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    This publication reports the results of a municipal and industrial water use inventory. Data reported covers the period 1960 through 1976. Time series information is aggregated from municipal and industrial system level to country and state totals. Total municipal and industrial withdrawals are divided between surface and groundwater sources. Yearly per capital withdrawal rates are estimated for 50 Utah municipalities and for each of Utah’s 29 counties. Per capita withdrawal rates range from a high of over 400 gallons per capita per day (gcd) in the communities of Delta, Fillmore, Hyrum, Logan, and Morgan to a low of 100 gcd in Bountiful, Washington, Terrace, Centerville, and South Ogden. A three year average (1974, 1975, and 1976) of Utah’s per capita withdrawal rate is 262 gcd. Also reported are return flow rates for 13 Utah waste treatment facilities. Withdrawal and return flow rates are also reported for Utah’s major water using industries. These rates are reported in gallons per employee per day (or gallons per unit of output). The publication also discusses methodologies for projecting municipal and industrial usage in Utah to the year 2020. Also reported are population projections for multicounty districts, counties and major cities by ten year intervals from 1960-2020

    Sustained nonoxidative glucose utilization and depletion of glycogen in reperfused canine myocardium

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    AbstractIschemically injured reperfused myocardium is characterized by increased 18F-fluorodeoxyglucose uptake as demonstrated by positron emission tomography. To elucidate the metabolic fate of exogenous glucose entering reperfused myocardium, D-[6-14C] glucose and L-[U-13C] lactate were used to determine glucose uptake, glucose oxidation and the contribution of exogenous glucose to lactate production. The pathologic model under investigation consisted of a 3 h balloon occlusion of the left anterior descending coronary artery followed by 24 h of reperfusion in canine myocardium. The extent and severity of myocardial injury after the ischemia and reperfusion were assessed by histochemical evaluation (triphenyltetrazolium chloride and periodic acid-Schiff stains). Thirteen intervention and four control dogs were studied.The glucose uptake in the occluded/reperfused area was significantly enhanced compared with that in control dogs (0.40 ± 0.14 versus 0.15 ± 0.10 μmol/ml, respectively). In addition, a significantly greater portion of the glucose extracted immediately entered glycolysis in the intervention group (75%) than in the control dogs (33%). The activity of the nonoxidative glycolytic pathway was markedly increased in the ischemically injured reperfused area, as evidenced by the four times greater lactate release in this area compared with the control value. The dual carbon-labeled isotopes showed that 57% of the exogenous glucose entering glycolysis was being converted to lactate. Exogenous glucose contributed to >90% of the observed lactate production. This finding was confirmed by the histochemical finding of sustained glycogen depletion in the occlusion/reperfusion area. The average area of glycogen depletion (37%) significantly exceeded the average area of necrosis (17%).These data demonstrate enhanced and sustained activity of the nonoxidative glycolytic pathway after a prolonged occlusion with reperfusion in canine myocardium. Because glycogen stores remain depleted, exogenous glucose becomes an important myocardial substrate under these pathologic conditions

    Levels, sources and chemical fate of persistent organic pollutants in the atmosphere and snow along the western Antarctic Peninsula

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    The Antarctic continent is among the most pristine regions; yet various organic contaminants have been measured there routinely. Air and snow samples were collected during the austral spring (October November, 2010) along the western Antarctic Peninsula and analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) to assess the relative importance of long-range transport versus local primary or secondary emissions. Highest concentrations of PCBs, PBDEs and DDTs were observed in the glacier\u27s snow sample, highlighting the importance of melting glaciers as a possible secondary source of legacy pollutants to the Antarctic. In the atmosphere, contaminants were mainly found in the vapor phase (\u3e65%). Hexachlorobenzene (33.6 pg/m(3)), PCBs (11.6 pg/m(3)), heptachlor (5.64 pg/m(3)), PBDEs (4.22 pg/m(3)) and cis-chlordane (2.43 pg/m(3)) were the most abundant contaminants. In contrast to other compounds, PBDEs seem to have originated from local sources, possibly the research station itself. Gas-particle partitioning for analytes were better predicted using the adsorption partitioning model than an octanol-based absorption approach. Diffusive flux calculations indicated that net deposition is the dominant pathway for PBDEs and chlordanes, whereas re-volatilization from snow (during melting or metamorphosis) was observed for PCBs and some OCPs. (C) 2016 Elsevier Ltd. All rights reserved

    Studies of CTNNBL1 and FDFT1 variants and measures of obesity: analyses of quantitative traits and case-control studies in 18,014 Danes

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    <p>Abstract</p> <p>Background</p> <p>A genome-wide scan in unrelated US Caucasians identified rs7001819 upstream of farnesyl-diphosphate farnesyltransferase 1 (<it>FDFT1</it>) and multiple variants within catenin (cadherin-associated protein), β-like 1 (<it>CTNNBL1</it>) to associate strongly with body mass index (BMI). The most significantly associating variants within <it>CTNNBL1 </it>including rs6013029 and rs6020846 were additionally confirmed to associate with morbid obesity in a French Caucasian case-control sample. The aim of this study was to investigate the impact of these three variants on obesity, through analyses of obesity-related quantitative traits, and case-control studies in large study samples of Danes.</p> <p>Methods</p> <p>The <it>FDFT1 </it>rs7001819, <it>CTNNBL1 </it>rs6013029 and rs6020846 were genotyped, using TaqMan allelic discrimination, in a combined study sample comprising 18,014 participants ascertained from; the population-based Inter99 cohort (<it>n </it>= 6,514), the ADDITION Denmark screening study cohort (<it>n </it>= 8,662), and a population-based sample (<it>n </it>= 680) and a type 2 diabetic patients group (<it>n </it>= 2,158) from Steno Diabetes Center.</p> <p>Results</p> <p>Both <it>CTNNBL1 </it>variants associated with body weight and height with per allele effect sizes of 1.0 [0.3–0.8] kg and 0.6 [0.2–0.9] cm, respectively, for the rs6020846 G-allele. No association was observed with BMI and waist circumference. In case-control studies neither of the <it>CTNNBL1 </it>variants showed association with overweight, obesity or morbid obesity (rs6013029: Odds Ratio (OR)<sub>overweight </sub>= 1.02 [0.90–1.16], OR<sub>obesity </sub>= 1.09 [0.95–1.25], OR<sub>morbidobesity </sub>= 1.26 [0.91–1.74]; rs6020846: OR<sub>overweight </sub>= 1.05 [0.93–1.18], OR<sub>obesity</sub>= 1.13 [1.00–1.28], OR<sub>morbidobesity </sub>= 1.17 [0.86–1.61]). However, in meta-analyses of the present and the previous study, both the rs6013029 T-allele and the rs6020846 G-allele increased the risk of developing morbid obesity (rs6013029: OR<sub>combined </sub>= 1.36 [1.12–1.64], <it>p </it>= 0.002; rs6020846: OR<sub>combined </sub>= 1.26 [1.06–1.51], <it>p </it>= 0.01), and obesity (rs6013029: OR<sub>combined </sub>= 1.17 [1.04–1.31], <it>p </it>= 0.007; rs6020846: OR<sub>combined </sub>= 1.17 [1.05–1.30], <it>p </it>= 0.004).</p> <p>The <it>FDFT1 </it>rs7001819 C-allele showed no association with obesity-related quantitative measures or dichotomous measures of overweight, obesity and morbid obesity.</p> <p>Conclusion</p> <p><it>CTNNBL1 </it>variants associated with body weight and height, and confer the risk of developing obesity in meta-analyses combining the present and a previous study. <it>FDFT1 </it>rs7001819 showed no association with obesity, neither when analysing quantitative traits nor when performing case-control studies of obesity.</p

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

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    The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured
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