7,417 research outputs found

    On Renyi entropies characterizing the shape and the extension of the phase space representation of quantum wave functions in disordered systems

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    We discuss some properties of the generalized entropies, called Renyi entropies and their application to the case of continuous distributions. In particular it is shown that these measures of complexity can be divergent, however, their differences are free from these divergences thus enabling them to be good candidates for the description of the extension and the shape of continuous distributions. We apply this formalism to the projection of wave functions onto the coherent state basis, i.e. to the Husimi representation. We also show how the localization properties of the Husimi distribution on average can be reconstructed from its marginal distributions that are calculated in position and momentum space in the case when the phase space has no structure, i.e. no classical limit can be defined. Numerical simulations on a one dimensional disordered system corroborate our expectations.Comment: 8 pages with 2 embedded eps figures, RevTex4, AmsMath included, submitted to PR

    A Lloyd-model generalization: Conductance fluctuations in one-dimensional disordered systems

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    We perform a detailed numerical study of the conductance GG through one-dimensional (1D) tight-binding wires with on-site disorder. The random configurations of the on-site energies ϵ\epsilon of the tight-binding Hamiltonian are characterized by long-tailed distributions: For large ϵ\epsilon, P(ϵ)1/ϵ1+αP(\epsilon)\sim 1/\epsilon^{1+\alpha} with α(0,2)\alpha\in(0,2). Our model serves as a generalization of 1D Lloyd's model, which corresponds to α=1\alpha=1. First, we verify that the ensemble average lnG\left\langle -\ln G\right\rangle is proportional to the length of the wire LL for all values of α\alpha, providing the localization length ξ\xi from lnG=2L/ξ\left\langle-\ln G\right\rangle=2L/\xi. Then, we show that the probability distribution function P(G)P(G) is fully determined by the exponent α\alpha and lnG\left\langle-\ln G\right\rangle. In contrast to 1D wires with standard white-noise disorder, our wire model exhibits bimodal distributions of the conductance with peaks at G=0G=0 and 11. In addition, we show that P(lnG)P(\ln G) is proportional to GβG^\beta, for G0G\to 0, with βα/2\beta\le\alpha/2, in agreement to previous studies.Comment: 5 pages, 5 figure

    Guidelines for fabrication of hybrid microcircuits

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    Document is summary of approaches that may be taken in designing hybrid microcircuits similar to those for aerospace application

    Elevated expression of type VII collagen in the skin of patients with systemic sclerosis. Regulation by transforming growth factor-beta.

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    A hallmark of systemic sclerosis (SSc) is the development of tissue fibrosis. Excessive production of several connective tissue components normally present in the dermis, including type I, III, V, and VI collagens as well as fibronectin and proteoglycans, is a consistent finding in the skin of SSc patients. Type VII collagen is a major constituent of anchoring fibrils, present in the skin at the dermal-epidermal basement membrane zone. TGF-beta has been shown to upregulate the expression of the type VII collagen gene. In this study, we assessed the expression of type VII collagen and TGF-beta in the skin of patients with SSc. Indirect immunofluorescence showed an abundance of type VII collagen in the patients\u27 skin, including the dermis. Ultrastructural analysis of SSc skin revealed an abundance of fibrillar material, possibly representing type VII collagen. The increased expression of type VII collagen epitopes was accompanied by the elevated expression of immunodetectable TGF-beta 1 and TGF-beta 2. Dermal fibroblasts cultured from the affected individuals showed a statistically significant (P \u3c 0.02) increase in the expression of type VII collagen at the mRNA level, as detected by reverse transcription-PCR with a mutated cDNA as an internal standard, and increased deposition of the protein as assessed by indirect immunofluorescence. Thus, type VII collagen is abundantly present in SSc patients\u27 dermis, a location not characteristic of its normal distribution, and its aberrant expression may relate to the presence of TGF-beta in the same topographic distribution. The presence of type VII collagen in the dermis may contribute to the tightly bound and indurated appearance of the affected skin in SSc patients

    First record of Deraeocoris fl avilinea in Hungary (Heteroptera, Miridae: Deraeocorinae)

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    Deraeocoris fl avilinea (A. Costa, 1862) is recorded for the fi rst time in Hungary. All individuals were collected from the canopies of Acer pseudoplatanus, A. platanoides and A. campestre. With 2 figures
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