143 research outputs found

    Using the Wigner-Ibach Surmise to Analyze Terrace-Width Distributions: History, User's Guide, and Advances

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    A history is given of the applications of the simple expression generalized from the surmise by Wigner and also by Ibach to extract the strength of the interaction between steps on a vicinal surface, via the terrace width distribution (TWD). A concise guide for use with experiments and a summary of some recent extensions are provided.Comment: 11 pages, 4 figures, reformatted (with revtex) version of refereed paper for special issue of Applied Physics A entitled "From Surface Science to Device Physics", in honor of the retirements of Prof. H. Ibach and Prof. H. L\"ut

    First Observation of Coherent π0\pi^0 Production in Neutrino Nucleus Interactions with EÎœ<E_{\nu}< 2 GeV

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    The MiniBooNE experiment at Fermilab has amassed the largest sample to date of π0\pi^0s produced in neutral current (NC) neutrino-nucleus interactions at low energy. This paper reports a measurement of the momentum distribution of π0\pi^0s produced in mineral oil (CH2_2) and the first observation of coherent π0\pi^0 production below 2 GeV. In the forward direction, the yield of events observed above the expectation for resonant production is attributed primarily to coherent production off carbon, but may also include a small contribution from diffractive production on hydrogen. Integrated over the MiniBooNE neutrino flux, the sum of the NC coherent and diffractive modes is found to be (19.5 ±\pm1.1 (stat) ±\pm2.5 (sys))% of all exclusive NC π0\pi^0 production at MiniBooNE. These measurements are of immediate utility because they quantify an important background to MiniBooNE's search for ΜΌ→Μe\nu_{\mu} \to \nu_e oscillations.Comment: Submitted to Phys. Lett.

    Test of Lorentz and CPT violation with Short Baseline Neutrino Oscillation Excesses

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    The sidereal time dependence of MiniBooNE electron neutrino and anti-electron neutrino appearance data are analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov-Smirnov test shows both the electron neutrino and anti-electron neutrino appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the electron neutrino appearance data prefer a sidereal time-independent solution, and the anti-electron neutrino appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10E-20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for muon neutrino to electron neutrino and anti-muon neutrino to anti-electron neutrino oscillations. The fit values and limits of combinations of SME coefficients are provided.Comment: 14 pages, 3 figures, and 2 tables, submitted to Physics Letters

    ARIA 2016: Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

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    The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma a

    Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

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    Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies

    Volume I. Introduction to DUNE

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE\u27s physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology

    Effects of 59Fe, 65Zn and of three soil types on dry matter yield, chemical composition and nitrogen fixation in Phaseolus vulgaris L. cv. carioca

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    The aim of this work was to study in greenhouse conditions the effects of two levels of iron and zinc on yield and chemical composition of common bean (Phaseolus vulgaris L.) and on atmospheric nitrogen fixation, in three soils, classified as Terra Roxa Estruturada (TRE), Latossol Vermelho Escuro (LVE), and Podzolico Vermelho Amarelo (PVA). The coefficient of utilization of these micronutrients by this crop and its distribution in above-ground parts and roots were also assessed. The rates for iron were 1.5 and 3.0 ppm, and for zinc, 2.5 and 5.0 ppm. It was applied 7.5 ”Ci of 59Fe/kg of soil with the lower rate of the stable iron, and 5.0 and 10.0 ”Ci of Zn/kg of soil in the pots corresponding to the lower and higher rate of the stable zinc, respectively. The plants were harveste at the age of 60 days and nitrogen, phosphorus, potassium, iron and zinc contents were determined. Immediately after harvest, symbiotic nitrogen fixation was assessed, using the acetylene reduction method. The detection of 59Fe and 65zn radioactivity were carried out on nitric percloric extract, by gamma ray spectrometry. The behavior of common bean presented high variation among the three soils, for all the variables. There was no influence of treatments of iron and zinc on dry matter of above ground part and root and also on the weight and number of nodules. The rate of 3.0 ppm of iron decreased the capacity of nodules to fix atmospheric nitrogen in relation to rate of 1.5 ppm, while the rate of 5.0 ppm of zinc increased this capacity, in relation to the rate of 2.5 ppm. There was significative effect of treatments on nitrogen, potassium and zinc contents in above ground part and on nitrogen and zinc contents in the root. The absorption of zinc from the fertilizer and the percentagem of zinc in the plant derived from fertilizer were diretly influenced by rate of zinc The higher coefficient of utilization of zinc from the fertilizer was 4.0%.No presente trabalho, conduzido em casa de vegetação, procuramos estudar os efeitos dos micronutrientes ferro e zinco na produção de materia seca, composição quĂ­mica do feijoeiro (Phaseolus vulgaris L.) e na fixação do nitrogĂȘnio atmosfĂ©rico, em trĂȘs solos, classificados como Terra Roxa Estruturada (TRE), Latossol Vermelho Escuro (LVE) e PodzĂłlico Vermelho Amarelo (PVA). Procuramos tambĂ©m determinar os Ă­ndices de aproveitamento destes micronutrientes pelo feijoeiro e sua distribuição na parte aĂ©rea e na raiz. O delineamento experimental foi um fatorial 3x7, sendo trĂȘs solos e sete tratamentos por solo, com trĂȘs repetiçÔes. Nos tratamentos, foram utilizados duas doses de ferro e duas doses de zinco em separado ou combinando as doses menores e maiores destes micronutrientes (Fe1Zn1, Fe2Zn2). As doses de ferro foram 1,5 e 3,0 ppm e as de zinco foram 2,5 e 5,0 ppm. Foram aplicados 7,5 ”Ci de 59Fe/kg de solo nos vasos correspondentes Ă  dose menor de ferro e 5,0 e 10,0 ”Ci de 65Zn/kg de solo nos vasos correspondentes respectivamente Ă  dose menor e maior de zinco. Todos os tratamentos receberam uma adubação bĂĄsica. O comportamento do feijoeiro apresentou grande variação entre os trĂȘs tipos de solos, para todas as variĂĄveis. NĂŁo houve influĂȘncia dos tratamentos de ferro e zinco na produção de parte aĂ©rea e raiz e nem no peso e numero dos nodulos. A dose de 3,0 ppm de ferro diminuiu a capacidade dos nĂłdulos de fixarem nitrogĂȘnio atmosfĂ©rico em relação Ă  dose de 1,5 ppm enquanto que a dose de 5,0 ppm de zinco aumentou esta capacidade, em relação Ă  dose de 2,5 ppm. Houve um efeito significativo dos tratamentos na concentração de nitrogĂȘnio, potĂĄssio, ferro e zinco na parte aĂ©rea e na concentração de nitrogĂȘnio, e zinco na raiz. A absorção de zinco dos fertilizantes e a percentagem do zinco na planta proveniente do adubo foram influenciadas diretamente pelas doses de zinco. O maior coeficiente de aproveitamento do zinco do adubo foi de 4,0%

    Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

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    The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

    Deep Underground Neutrino Experiment (DUNE), far detector technical design report, volume III: DUNE far detector technical coordination

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume III of this TDR describes how the activities required to design, construct, fabricate, install, and commission the DUNE far detector modules are organized and managed. This volume details the organizational structures that will carry out and/or oversee the planned far detector activities safely, successfully, on time, and on budget. It presents overviews of the facilities, supporting infrastructure, and detectors for context, and it outlines the project-related functions and methodologies used by the DUNE technical coordination organization, focusing on the areas of integration engineering, technical reviews, quality assurance and control, and safety oversight. Because of its more advanced stage of development, functional examples presented in this volume focus primarily on the single-phase (SP) detector module

    Highly-parallelized simulation of a pixelated LArTPC on a GPU

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    The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype
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