384 research outputs found

    An updated analysis of NN elastic scattering data to 1.6 GeV

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    An energy-dependent and set of single-energy partial-wave analyses of NNNN elastic scattering data have been completed. The fit to 1.6~GeV has been supplemented with a low-energy analysis to 400 MeV. Using the low-energy fit, we study the sensitivity of our analysis to the choice of πNN\pi NN coupling constant. We also comment on the possibility of fitting npnp data alone. These results are compared with those found in the recent Nijmegen analyses. (Figures may be obtained from the authors upon request.)Comment: 17 pages of text, VPI-CAPS-7/

    On derivation of Euler-Lagrange Equations for incompressible energy-minimizers

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    We prove that any distribution qq satisfying the equation ∇q=Ă·f\nabla q=\div{\bf f} for some tensor f=(fji),fji∈hr(U){\bf f}=(f^i_j), f^i_j\in h^r(U) (1≀r<∞1\leq r<\infty) -the {\it local Hardy space}, qq is in hrh^r, and is locally represented by the sum of singular integrals of fjif^i_j with Calder\'on-Zygmund kernel. As a consequence, we prove the existence and the local representation of the hydrostatic pressure pp (modulo constant) associated with incompressible elastic energy-minimizing deformation u{\bf u} satisfying ∣∇u∣2,∣cof∇u∣2∈h1|\nabla {\bf u}|^2, |{\rm cof}\nabla{\bf u}|^2\in h^1. We also derive the system of Euler-Lagrange equations for incompressible local minimizers u{\bf u} that are in the space Kloc1,3K^{1,3}_{\rm loc}; partially resolving a long standing problem. For H\"older continuous pressure pp, we obtain partial regularity of area-preserving minimizers.Comment: 23 page

    Whirl mappings on generalised annuli and the incompressible symmetric equilibria of the dirichlet energy

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    In this paper we show a striking contrast in the symmetries of equilibria and extremisers of the total elastic energy of a hyperelastic incompressible annulus subject to pure displacement boundary conditions.Indeed upon considering the equilibrium equations, here, the nonlinear second order elliptic system formulated for the deformation u=(u1,
,uN) : EL[u,X]=⎧⎩⎚âŽȘâŽȘΔu=div(P(x)cof∇u)det∇u=1uâ‰ĄÏ†inX,inX,on∂X, where X is a finite, open, symmetric N -annulus (with N≄2 ), P=P(x) is an unknown hydrostatic pressure field and φ is the identity mapping, we prove that, despite the inherent rotational symmetry in the system, when N=3 , the problem possesses no non-trivial symmetric equilibria whereas in sharp contrast, when N=2 , the problem possesses an infinite family of symmetric and topologically distinct equilibria. We extend and prove the counterparts of these results in higher dimensions by way of showing that a similar dichotomy persists between all odd vs. even dimensions N≄4 and discuss a number of closely related issues

    Genome-to-genome analysis highlights the effect of the human innate and adaptive immune systems on the hepatitis C virus

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    Outcomes of hepatitis C virus (HCV) infection and treatment depend on viral and host genetic factors. Here we use human genome-wide genotyping arrays and new whole-genome HCV viral sequencing technologies to perform a systematic genome-to-genome study of 542 individuals who were chronically infected with HCV, predominantly genotype 3. We show that both alleles of genes encoding human leukocyte antigen molecules and genes encoding components of the interferon lambda innate immune system drive viral polymorphism. Additionally, we show that IFNL4 genotypes determine HCV viral load through a mechanism dependent on a specific amino acid residue in the HCV NS5A protein. These findings highlight the interplay between the innate immune system and the viral genome in HCV control

    Electromagnetic and Hadron Calorimeters in the MIPP Experiment

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    The purpose of the MIPP experiment is to study the inclusive production of photons, pions, kaons and nucleons in pi, K and p interactions on various targets using beams from the Main Injector at Fermilab. The function of the calorimeters is to measure the production of forward-going neutrons and photons. The electromagnetic calorimeter consist of 10 lead plates interspersed with proportional chambers. It was followed by the hadron calorimeter with 64 steel plates interspersed with scintillator. The data presented were collected with a variety of targets and beam momenta from 5 GeV/c to 120 GeV/c. The energy calibration of both calorimeters with electrons, pions, kaons, and protons is discussed. The resolution for electrons was found to be 0.27/sqrt(E), and for hadrons the resolution was 0.554/sqrt(E) with a constant term of 2.6%. The performance of the calorimeters was tested on a neutron sample

    A Soil Management Assessment Framework (SMAF) Evaluation of Brazilian Sugarcane Expansion on Soil Quality

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    The Soil Management Assessment Framework (SMAF) was developed to evaluate impacts of land use and management practices on soil quality (SQ), but its suitability for Brazilian tropical soils was unknown. We hypothesized that SMAF would be sensitive enough to detect SQ changes associated with sugarcane (Saccharum officinarum L.) expansion for ethanol production. Field studies were performed at three sites across the south-central region of Brazil, aiming to quantify the impacts of a land use change sequence (i.e., native vegetation–pasture–sugarcane) on SQ. Eight soil indicators were individually scored using SMAF curves developed primarily for North American soils and integrated into an overall Soil Quality Index (SQI) and its chemical, physical, and biological sectors. The SMAF scores were correlated with two other approaches used to assess SQ changes, soil organic C (SOC) stocks and Visual Evaluation of Soil Structure (VESS) scores. Our findings showed that the SMAF was an efficient tool for assessing land use change effects on the SQ of Brazilian tropical soils. The SMAF scoring curves developed using robust algorithms allowed proper assignment of scores for the soil chemical, physical, and biological indicators assessed. The SQI scores were significantly correlated with SOC stocks and VESS scores. Long-term transition from native vegetation to extensive pasture promoted significant decreases in soil chemical, physical, and biological indicators. Overall SQI suggested that soils under native vegetation were functioning at 87% of their potential capacity, while pasture soils were functioning at 70%. Conversions of pasture to sugarcane induced slight improvements in SQ, primarily because of improved soil fertility. Sugarcane soils are functioning at 74% of their potential capacity. Based on this study, management strategies were developed to improve SQ and the sustainability of sugarcane production in Brazil

    Analytic properties of the Landau gauge gluon and quark propagators

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    We explore the analytic structure of the gluon and quark propagators of Landau gauge QCD from numerical solutions of the coupled system of renormalized Dyson--Schwinger equations and from fits to lattice data. We find sizable negative norm contributions in the transverse gluon propagator indicating the absence of the transverse gluon from the physical spectrum. A simple analytic structure for the gluon propagator is proposed. For the quark propagator we find evidence for a mass-like singularity on the real timelike momentum axis, with a mass of 350 to 500 MeV. Within the employed Green's functions approach we identify a crucial term in the quark-gluon vertex that leads to a positive definite Schwinger function for the quark propagator.Comment: 42 pages, 16 figures, revtex; version to be published in Phys Rev
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