34,146 research outputs found

    Impact of edge-removal on the centrality betweenness of the best spreaders

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    The control of epidemic spreading is essential to avoid potential fatal consequences and also, to lessen unforeseen socio-economic impact. The need for effective control is exemplified during the severe acute respiratory syndrome (SARS) in 2003, which has inflicted near to a thousand deaths as well as bankruptcies of airlines and related businesses. In this article, we examine the efficacy of control strategies on the propagation of infectious diseases based on removing connections within real world airline network with the associated economic and social costs taken into account through defining appropriate quantitative measures. We uncover the surprising results that removing less busy connections can be far more effective in hindering the spread of the disease than removing the more popular connections. Since disconnecting the less popular routes tend to incur less socio-economic cost, our finding suggests the possibility of trading minimal reduction in connectivity of an important hub with efficiencies in epidemic control. In particular, we demonstrate the performance of various local epidemic control strategies, and show how our approach can predict their cost effectiveness through the spreading control characteristics.Comment: 11 pages, 4 figure

    Vocal learning promotes patterned inhibitory connectivity.

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    Skill learning is instantiated by changes to functional connectivity within premotor circuits, but whether the specificity of learning depends on structured changes to inhibitory circuitry remains unclear. We used slice electrophysiology to measure connectivity changes associated with song learning in the avian analog of primary motor cortex (robust nucleus of the arcopallium, RA) in Bengalese Finches. Before song learning, fast-spiking interneurons (FSIs) densely innervated glutamatergic projection neurons (PNs) with apparently random connectivity. After learning, there was a profound reduction in the overall strength and number of inhibitory connections, but this was accompanied by a more than two-fold enrichment in reciprocal FSI-PN connections. Moreover, in singing birds, we found that pharmacological manipulations of RA's inhibitory circuitry drove large shifts in learned vocal features, such as pitch and amplitude, without grossly disrupting the song. Our results indicate that skill learning establishes nonrandom inhibitory connectivity, and implicates this patterning in encoding specific features of learned movements

    Water Vapour Effects in Mass Measurement

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    Water vapour inside the mass comparator enclosure is a critical parameter. In fact, fluctuations of this parameter during mass weighing can lead to errors in the determination of an unknown mass. To control that, a proposal method is given and tested. Preliminary results of our observation of water vapour sorption and desorption processes from walls and mass standard are reported

    Particle dispersion models and drag coefficients for particles in turbulent flows

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    Some of the concepts underlying particle dispersion due to turbulence are reviewed. The traditional approaches to particle dispersion in homogeneous, stationary turbulent fields are addressed, and recent work on particle dispersion in large scale turbulent structures is reviewed. The state of knowledge of particle drag coefficients in turbulent gas-particle flows is also reviewed

    Discovering the Higgs Bosons of Minimal Supersymmetry with Muons and a Bottom Quark

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    We investigate the prospects for the discovery at the CERN Large Hadron Collider of a neutral Higgs boson produced with one bottom quark followed by Higgs decay into a muon pair. We work within the framework of the minimal supersymmetric model. The dominant physics background from the production of bμ+μb \mu^+\mu^-, jμ+μj\mu^+\mu^-, j=g,u,d,s,c, and bbˉW+Wb {\bar b} W^+W^- is calculated with realistic acceptance cuts. Promising results are found for the CP-odd pseudoscalar (A0A^0) and the heavier CP-even scalar (H0H^0) Higgs bosons with masses up to 600 GeV. This discovery channel with one energetic bottom quark greatly improves the discovery potential of the LHC beyond the inclusive channel ppϕ0μ+μ+Xpp\to \phi^0\to \mu^+\mu^- +X.Comment: Version to appear in Phys. Rev. Let

    Adjacency labeling schemes and induced-universal graphs

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    We describe a way of assigning labels to the vertices of any undirected graph on up to nn vertices, each composed of n/2+O(1)n/2+O(1) bits, such that given the labels of two vertices, and no other information regarding the graph, it is possible to decide whether or not the vertices are adjacent in the graph. This is optimal, up to an additive constant, and constitutes the first improvement in almost 50 years of an n/2+O(logn)n/2+O(\log n) bound of Moon. As a consequence, we obtain an induced-universal graph for nn-vertex graphs containing only O(2n/2)O(2^{n/2}) vertices, which is optimal up to a multiplicative constant, solving an open problem of Vizing from 1968. We obtain similar tight results for directed graphs, tournaments and bipartite graphs

    Constraints on a new alternative model to dark energy

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    The recent type Ia supernova data suggest that the universe is accelerating now and decelerated in recent past. This may provide the evidence that the standard Friedmann equation needs to be modified. We analyze in detail a new model in the context of modified Friedmann equation using the supernova data published by the High-zz Supernova Search Team and the Supernova Cosmology Project. The new model explains recent acceleration and past deceleration. Furthermore, the new model also gives a decelerated universe in the future.Comment: 12 pages, 5 figures, use ws-ijmpd, minor changes made. In the new version, a detailed derivation of the model is give
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