1,994 research outputs found

    Orbiting valence quarks and their influence on the structure functions of the nucleon

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    It is shown that intrinsic orbital motion of the valence quarks has large influences on the spin-dependent as well as the spin-averaged nucleon structure functions. Its connection with the observed ``very small contribution of quark spin to nucleon spin'' and the observed violation of Gottfried sum rule is discussed.Comment: 10 pages (LaTeX) including 3 figure

    On the high strain rate behavior of 63-37 Sn-Pb eutectic solders with temperature effects

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    This study presents experimental results performed on samples of Eutectic solder material (63 wt. % Sn 37 wt. % Pb) loaded at high strain rates and elevated temperatures. The tests were performed at high strain rates using Split Hopkinson Pressure Bar (SHPB). The strain rates were in the range of 400 s-1to 1300 s-1. Heating unit was added to conventional SHPB to vary sample' s initial temperature conditions. Tests were conducted at three initial temperatures, i.e. room temperature, 60 °C and 120 °C for compressive mode. The effects of temperature on the behavior of material were compared. Transient temperature changes during dynamic loading conditions are calculated by an analytical approach using measured stress-strain data for plastic work. Test results were fitted into the Johnson-Cook model (JC model). In addition, dynamic tests were performed in tension mode using Split Hopkinson Tensile Bar (SHTB) at room temperature

    Likelihood Of Achieving Who Leprosy Goals: An Expert Survey

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    Much progress has been made in the global fight against leprosy, as evidenced by dramatic declines in prevalence rates in recent years. However, leprosy has proven elusive. New case detection rates have remained fairly stable, particularly in countries with remaining pockets of high endemicity such as India, Brazil, and Indonesia. In 2012, the World Health Organization spearheaded the London Declaration, which in part aimed for the goal of interruption of transmission of global leprosy by 2020. Aggregating the opinions of experts can supplement existing data to help determine the feasibility of reaching the WHO goals. To obtain the opinions of experts, a cross-sectional survey was sent requesting experts to give probabilistic estimates on the likelihood of achieving leprosy control targets. The survey results showed that most experts do not think the 2020 leprosy control targets will be met. The majority of experts indicated enhanced case finding as the most important measure to undertake to improve leprosy control goal success. The collection of expert opinions highlights the need for continued attention on leprosy from a public health standpoint

    Criticality in quark-gluon systems far beyond thermal and chemical equilibrium

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    Experimental evidence and theoretical arguments for the existence of self-organized criticality in systems of gluons and quarks are presented. It is observed that the existing data for high-transverse-momentum jet-production exhibit striking regularities; and it is shown that, together with first-principle considerations, such regularities can be used, not only to probe the possible compositness of quarks, but also to obtain {\em direct evidence} for, or against, the existence of critical temperature and/or critical chemical potential in quark-gluon systems when hadrons are squeezed together.Comment: 13 pages, including 1 figure and 1 tabl

    Formation of color-singlet gluon-clusters and inelastic diffractive scattering

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    This is the extensive follow-up report of a recent Letter in which the existence of self-organized criticality (SOC) in systems of interacting soft gluons is proposed, and its consequences for inelastic diffractive scattering processes are discussed. It is pointed out, that color-singlet gluon-clusters can be formed in hadrons as a consequence of SOC in systems of interacting soft gluons, and that the properties of such spatiotemporal complexities can be probed experimentally by examing inelastic diffractive scattering. Theoretical arguments and experimental evidences supporting the proposed picture are presented --- together with the result of a systematic analysis of the existing data for inelastic diffractive scattering processes performed at different incident energies, and/or by using different beam-particles. It is shown in particular that the size- and the lifetime-distributions of such gluon-clusters can be directly extracted from the data, and the obtained results exhibit universal power-law behaviors --- in accordance with the expected SOC-fingerprints. As further consequences of SOC in systems of interacting soft gluons, the tt-dependence and the (Mx2/s)(M_x^2/s)-dependence of the double differential cross-sections for inelastic diffractive scattering off proton-target are discussed. Here tt stands for the four-momentum-transfer squared, MxM_x for the missing mass, and s\sqrt{s} for the total c.m.s. energy. It is shown, that the space-time properties of the color-singlet gluon-clusters due to SOC, discussed above, lead to simple analytical formulae for d2σ/dtd(Mx2/s)d^2\sigma/dt d(M_x^2/s) and for dσ/dtd\sigma/dt, and that the obtained results are in good agreement with the existing data. Further experiments are suggested.Comment: 67 pages, including 11 figure
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