717 research outputs found

    Abelian Magnetic Monopoles and Topologically Massive Vector Bosons in Scalar-Tensor Gravity with Torsion Potential

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    A Lagrangian formulation describing the electromagnetic interaction - mediated by topologically massive vector bosons - between charged, spin-(1/2) fermions with an abelian magnetic monopole in a curved spacetime with non-minimal coupling and torsion potential is presented. The covariant field equations are obtained. The issue of coexistence of massive photons and magnetic monopoles is addressed in the present framework. It is found that despite the topological nature of photon mass generation in curved spacetime with isotropic dilaton field, the classical field theory describing the nonrelativistic electromagnetic interaction between a point-like electric charge and magnetic monopole is inconsistent.Comment: 18 pages, no figure

    Technology study of passive control of humidity in space suits

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    Water vapor condensation and adsorption techniques for passive humidity control in space suit

    Analytical review of passive mass transfer of water vapor in a space suit

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    Engineering study and analysis of water vapor mass transfer in space sui

    Quantum information reclaiming after amplitude damping

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    We investigate the quantum information reclaim from the environment after amplitude damping has occurred. In particular we address the question of optimal measurement on the environment to perform the best possible correction on two and three dimensional quantum systems. Depending on the dimension we show that the entanglement fidelity (the measure quantifying the correction performance) is or is not the same for all possible measurements and uncover the optimal measurement leading to the maximum entanglement fidelity

    Suggestive hypothesis on a case report: Patient presenting with cyclical ovarian cysts coupled to increased cholestatic enzymes

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    We describe the case of a childbearing-age woman presenting with spontaneous recurrent functional ovarian cysts and, more interestingly, chronic and asymptomatic elevation of cholestatic parameters. The patient showed no history of chronic viral infections, immunological and metabolic disorders, alcohol abuse and environmental toxins exposition. Hepatic ultrasonography and cholangio-pancreatography-magnetic-resonance excluded any morphological and structural abnormalities, while liver biopsy evidenced only minimal and not specific features of inflammation. Cholestasis indices obtained prompt recovery after each cycle of synthetic hormone therapy, implanted to treat functional ovarian cysts. She has continuously experienced the off-therapy asynchronous recurrence of liver laboratory abnormalities and functional ovarian cysts. The favorable effect of the synthetic hormone therapy to obtaining a stable recovery of this unexplained long-lasting cholestatic syndrome could be likely explained by downregulation of an endogenous ovarian overproduction, although estrogen-regulated local intracellular transduction pathways cannot be excluded

    Interferometer Response to Scalar Gravitational Waves

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    It was recently suggested that the magnetic component of Gravitational Waves (GWs) is relevant in the evaluation of frequency response functions of gravitational interferometers. In this paper we extend the analysis to the magnetic component of the scalar mode of GWs which arise from scalar-tensor gravity theory. In the low-frequency approximation, the response function of ground-based interferometers is calculated. The angular dependence of the electric and magnetic contributions to the response function is discussed. Finally, for an arbitrary frequency range, the proper distance between two test masses is calculated and its usefulness in the high-frequency limit for space-based interferometers is briefly considered.Comment: Accepted for publication by Int. Journ. Mod. Phys. D. Final versio

    Complexity Characterization in a Probabilistic Approach to Dynamical Systems Through Information Geometry and Inductive Inference

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    Information geometric techniques and inductive inference methods hold great promise for solving computational problems of interest in classical and quantum physics, especially with regard to complexity characterization of dynamical systems in terms of their probabilistic description on curved statistical manifolds. In this article, we investigate the possibility of describing the macroscopic behavior of complex systems in terms of the underlying statistical structure of their microscopic degrees of freedom by use of statistical inductive inference and information geometry. We review the Maximum Relative Entropy (MrE) formalism and the theoretical structure of the information geometrodynamical approach to chaos (IGAC) on statistical manifolds. Special focus is devoted to the description of the roles played by the sectional curvature, the Jacobi field intensity and the information geometrodynamical entropy (IGE). These quantities serve as powerful information geometric complexity measures of information-constrained dynamics associated with arbitrary chaotic and regular systems defined on the statistical manifold. Finally, the application of such information geometric techniques to several theoretical models are presented.Comment: 29 page

    Expression and purification of the recombinant subunits of toluene/o-xylene monooxygenase and reconstitution of the active complex.

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    This paper describes the cloning of the genes coding for each component of the complex of toluene/o-xylene monooxygenase from Pseudomonas stutzeri OX1, their expression, purification and characterization. Moreover, the reconstitution of the active complex from the recombinant subunits has been obtained, and the functional role of each component in the electron transfer from the electron donor to molecular oxygen has been determined. The coexpression of subunits B, E and A leads to the formation of a subcomplex, named H, with a quaternary structure (BEA)2, endowed with hydroxylase activity. Tomo F component is an NADH oxidoreductase. The purified enzyme contains about 1 mol of FAD, 2 mol of iron, and 2 mol of acid labile sulfide per mol of protein, as expected for the presence of one [2Fe-2S] cluster, and exhibits a typical flavodoxin absorption spectrum. Interestingly, the sequence of the protein does not correspond to that previously predicted on the basis of DNA sequence. We have shown that this depends on minor errors in the gene sequence that we have corrected. C component is a Rieske-type ferredoxin, whose iron and acid labile sulfide content is in agreement with the presence of one [2Fe-2S] cluster. The cluster is very sensitive to oxygen damage. Mixtures of the subcomplex H and of the subunits F, C and D are able to oxidize p-cresol into 4-methylcathecol, thus demonstrating the full functionality of the recombinant subunits as purified. Finally, experimental evidence is reported which strongly support a model for the electron transfer. Subunit F is the first member of an electron transport chain which transfers electrons from NADH to C, which tunnels them to H subcomplex, and eventually to molecular oxyge

    HIV-1 Tat protein modulates the generation of cytotoxic T cell epitopes by modifying proteasome composition and enzymatic activity

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    Tat, the trans activation protein of HIV, is produced early upon infection to promote and expand HIV replication and transmission. However, Tat appears to also have effects on target cells, which may affect Ag recognition both during infection and after vaccination. In particular, Tat targets dendritic cells and induces their maturation and Ag-presenting functions, increasing Th1 T cell responses. We show in this work that Tat modifies the catalytic subunit composition of immunoproteasomes in B and T cells either expressing Tat or treated with exogenous biological active Tat protein. In particular, Tat up-regulates latent membrane protein 7 and multicatalytic endopeptidase complex like-1 subunits and down-modulates the latent membrane protein 2 subunit. These changes correlate with the increase of all three major proteolytic activities of the proteasome and result in a more efficient generation and presentation of subdominant MHC-I-binding CTL epitopes of heterologous Ags. Thus, Tat modifies the Ag processing and modulates the generation of CTL epitopes. This may have an impact on both the control of virally infected cells during HIV-1 infection and the use of Tat for vaccination strategies
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