28,110 research outputs found

    Nucleation in the chiral transition with an inhomogeneous background

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    We consider an approximation procedure to evaluate the finite-temperature one-loop fermionic density in the presence of a chiral background field which systematically incorporates effects from inhomogeneities in the chiral field through a derivative expansion. Modifications in the effective potential and their consequences for the bubble nucleation process are discussed.Comment: 4 pages, 4 figures. To appear in the proceedings of I Latin American Workshop on High Energy Phenomenology (LAWHEP 2005), Porto Alegre, Brazil, 1-3 Dec 200

    Geometric phase and gauge theory structure in quantum computing

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    We discuss the presence of a geometrical phase in the evolution of a qubit state and its gauge structure. The time evolution operator is found to be the free energy operator, rather than the Hamiltonian operator.Comment: 5 pages, presented at Fifth International Workshop DICE2010: Space-Time-Matter - current issues in quantum mechanics and beyond, Castiglioncello (Tuscany), September 13-17, 201

    Optimal placement of excitations and sensors by simulated annealing

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    The optimal placement of discrete actuators and sensors is posed as a combinatorial optimization problem. Two examples for truss structures were used for illustration; the first dealt with the optimal placement of passive dampers along existing truss members, and the second dealt with the optimal placement of a combination of a set of actuators and a set of sensors. Except for the simplest problems, an exact solution by enumeration involves a very large number of function evaluations, and is therefore computationally intractable. By contrast, the simulated annealing heuristic involves far fewer evaluations and is best suited for the class of problems considered. As an optimization tool, the effectiveness of the algorithm is enhanced by introducing a number of rules that incorporate knowledge about the physical behavior of the problem. Some of the suggested rules are necessarily problem dependent

    Extracellular vesicles: A therapeutic option for liver fibrosis

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    Extracellular vesicles (EVs) are a heterogeneous population of small membrane vesicles released by all types of cells in both physiological and pathological conditions. EVs shuttle different types of molecules and are able to modify the behavior of target cells by various mechanisms of action. In this review, we have summarized the papers present in the literature, to our acknowledge, that reported the EV effects on liver diseases. EVs purified from serum, stem cells, and hepatocytes were investigated in different experimental in vivo models of liver injury and in particular of liver fibrosis. Despite the different EV origin and the different types of injury (toxic, ischemic, diet induced, and so on), EVs showed an anti-fibrotic effect. In particular, EVs had the capacities to inhibit activation of hepatic stellate cells, one of the major players of liver fibrosis development; to reduce inflammation and apoptosis; to counteract the oxidative stress; and to increase hepatocyte proliferation, contributing to reducing fibrosis and ameliorating liver function and morphology
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