704 research outputs found

    Nuclear medium modifications of properties of kaons measured around threshold with FOPI

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    We report on the investigation of modifications of basic properties of K+^+ and K^- mesons emitted from collisions of Ni+Ni at beam energy of 1.91A GeV. Experimental K^-/K+^+ ratio are presented in a wide range of phase space parameterized by kinetic energy and emission angle in the nucleon-nucleon centre of mass. The v1v_1 component of the azimuthal distribution was extracted as a function of rapidity and transverse momentum for central, and semi-peripheral collisions. A comparison of these patterns with the HSD transport model favours the existence of the kaon-nucleon in-medium potential. For the IQMD model, this interaction scenario is confirmed in case of K^-, whereas for K+^+ the picture is less clear.Comment: 7 pages, 3 figures, proceedings article of the 55th International Winter Meeting on Nuclear Physics, Bormio (Italy) 201

    Field induced stationary state for an accelerated tracer in a bath

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    Our interest goes to the behavior of a tracer particle, accelerated by a constant and uniform external field, when the energy injected by the field is redistributed through collision to a bath of unaccelerated particles. A non equilibrium steady state is thereby reached. Solutions of a generalized Boltzmann-Lorentz equation are analyzed analytically, in a versatile framework that embeds the majority of tracer-bath interactions discussed in the literature. These results --mostly derived for a one dimensional system-- are successfully confronted to those of three independent numerical simulation methods: a direct iterative solution, Gillespie algorithm, and the Direct Simulation Monte Carlo technique. We work out the diffusion properties as well as the velocity tails: large v, and either large -v, or v in the vicinity of its lower cutoff whenever the velocity distribution is bounded from below. Particular emphasis is put on the cold bath limit, with scatterers at rest, which plays a special role in our model.Comment: 20 pages, 6 figures v3:minor corrections in sec.III and added reference

    Emission patterns of neutral pions in 40 A MeV Ta+Au reactions

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    Differential cross sections of neutral pions emitted in 181Ta + 197Au collisions at a beam energy of 39.5A MeV have been measured with the photon spectrometer TAPS. The kinetic energy and transverse momentum spectra of neutral pions cannot be properly described in the framework of the thermal model, nor when the reabsorption of pions is accounted for in a phenomenological model. However, high energy and high momentum tails of the pion spectra can be well fitted through thermal distributions with unexpectedly soft temperature parameters below 10 MeV.Comment: 16 pages (double-spaced), 5 figures; corrections after referee's comments and suggestion

    Effective conductivity in association with model structure and spatial inhomogeneity of polymer/carbon black composites

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    The relationship between effective conductivity and cell structure of polyethylene/carbon composites as well as between effective conductivity and spatial distribution of carbon black are discussed. Following Yoshida's model both structures can, in a way, be said to be intermediate between the well known Maxwell-Garnett (MG) and Bruggeman (BR) limiting structures. Using TEM photographs on composites with various carbon blacks we have observed that the larger is Garncarek's inhomogeneity measure H of two-dimensional (2D) representative distribution of the carbon black, the smaller is the effective conductivity of the composite.Comment: 7 pages, 9 figure

    Agenesis of the long head of the biceps brachii tendon: ignored variations of the anatomy and the next tendon to disappear?

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    Bilateral agenesis of the long head of the biceps brachial tendon (LHB) is a very rare variation of the anatomy. We report a case of an 18-year-old man with bilateral agenesis of the long head of the biceps brachii tendon. We present initial findings, radiographical examinations and the follow-up of an unusual entity. Diagnosis of agenesis of the LHB can be challenging especially in cases of traumatic shoulder pain. It is not a very known entity because of its rareness. However, it could be associated with other congenital anomalies. The absence of the LHB is easily ignored in the diagnostic process. Clinical examination should be a pitfall, radiological examination is helpful to confirm the suspicion of LHB absence. MRI is often the first choice, although ultrasonography is cheaper and much easier to access and it is an excellent tool to visualise this anatomic variation with empty or shallow intertubercular groove

    Some geometrical methods for constructing contradiction measures on Atanassov's intuitionistic fuzzy sets

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    Trillas et al. (1999, Soft computing, 3 (4), 197–199) and Trillas and Cubillo (1999, On non-contradictory input/output couples in Zadeh's CRI proceeding, 28–32) introduced the study of contradiction in the framework of fuzzy logic because of the significance of avoiding contradictory outputs in inference processes. Later, the study of contradiction in the framework of Atanassov's intuitionistic fuzzy sets (A-IFSs) was initiated by Cubillo and Castiñeira (2004, Contradiction in intuitionistic fuzzy sets proceeding, 2180–2186). The axiomatic definition of contradiction measure was stated in Castiñeira and Cubillo (2009, International journal of intelligent systems, 24, 863–888). Likewise, the concept of continuity of these measures was formalized through several axioms. To be precise, they defined continuity when the sets ‘are increasing’, denominated continuity from below, and continuity when the sets ‘are decreasing’, or continuity from above. The aim of this paper is to provide some geometrical construction methods for obtaining contradiction measures in the framework of A-IFSs and to study what continuity properties these measures satisfy. Furthermore, we show the geometrical interpretations motivating the measures

    Physics Analysis Expert PAX: First Applications

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    PAX (Physics Analysis Expert) is a novel, C++ based toolkit designed to assist teams in particle physics data analysis issues. The core of PAX are event interpretation containers, holding relevant information about and possible interpretations of a physics event. Providing this new level of abstraction beyond the results of the detector reconstruction programs, PAX facilitates the buildup and use of modern analysis factories. Class structure and user command syntax of PAX are set up to support expert teams as well as newcomers in preparing for the challenges expected to arise in the data analysis at future hadron colliders.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 7 pages, LaTeX, 10 eps figures. PSN THLT00

    Measurement of muscle health in aging

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    Muscle health is a critical component in the struggle against physical frailty and the efforts to maintain metabolic health until the limit of chronological age. Consensus opinion is to evaluate muscle health in terms of muscle mass, strength and functional capability. There has been considerable variability in the components of muscle health which have been investigated in addition to variability in the tools of assessment and protocol for measurement. This is in stark contrast to the validated measurement of bone health across the adult life span. The purpose of this review was to identify indices of muscle mass, strength and functional capability most responsive to change with ageing and where possible to provide an estimate of the rate of change. We suggest lean tissue mass (LTM) or skeletal muscle (SM) is best evaluated from the thigh region due to its greater responsiveness to ageing compared to the whole body. The anterior compartment of the thigh region undergoes a preferential age-related decline in SM and force generating capacity. Therefore, we suggest that knee extensor torque is measured to represent the force generating capacity of the thigh and subsequently, to express muscle quality (strength per unit tissue). Finally, we suggest measures of functional capability which allow participants perform to a greater maximum are most appropriate to track age-related difference in functional capacity across the adult lifespan. This is due to their ability encompass a broad spectrum of abilities. This review suggests indices of muscular health for which reference ranges can be generated across the lifespan

    Difficulties in the Production of Ausferritic Nodular Cast Iron without Heat Treatment

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    The paper presents results of tests carried out on ausferrite carbide matrix alloyed ductile cast iron. The ausferrite was obtained via addition of Cu and Mo alloying elements. This eliminated heat treatment from the alloy production cycle. The article presents results of tests of the quality of the obtained material. Emphasis was put on metallographic analysis using light and scanning microscopy. Works also included chemical composition tests and EDS analysis. Strength tests were executed in an accredited laboratory. It is possible to create a raw ausferrite carbide matrix without subjecting an alloy to heat treatment. However, it turned out that quality parameters of cast iron were insufficient. The obtained material hardness was 515 HB, while Rm strength and A5 ductility were very low. The low tensile strength of the analyzed alloy resulted from the presence of degenerate graphite secretion (of flake or vermicular shape) in the cast iron. The tests also demonstrated that the alloy was prone to shrinkage-related porosity, which further weakened the material. Alloys made of alloyed ductile iron of ausferrite matrix micro-structure are very attractive due to elimination of the heat treatment process. However, their production process and chemical composition must be optimized
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