232,938 research outputs found

    The Electroweak Chiral Lagrangian and New Precision Measurements

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    A revised and complete list of the electroweak chiral lagrangian operators up to dimension-four is provided. The connection of these operators to the SS, TT and UU parameters and the parameters describing the triple gauge boson vertices WWγWW\gamma and WWZWWZ is made, and the size of these parameters from new heavy physics is estimated using a one flavor-doublet model of heavy fermions. The coefficients of the chiral lagrangian operators are also computed in this model.Comment: 21 pages, LaTex, 2 figures (not included), YCTP-P7-9

    Model of energy spectrum parameters of ground level enhancement events in solar cycle 23

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    Mewaldt et al. 2012 fitted the observations of the ground level enhancement (GLE) events during solar cycle 23 to the double power-law equation to obtain the four energy spectra parameters, the normalization parameter CC, low-energy power-law slope γ1\gamma_1, high-energy power-law slope γ2\gamma_2, and break energy E0E_0. There are 16 GLEs from which we select 1313 for study by excluding some events with complicated situation. We analyze the four parameters with conditions of the corresponding solar events. According to solar event conditions we divide the GLEs into two groups, one with strong acceleration by interplanetary (IP) shocks and another one without strong acceleration. By fitting the four parameters with solar event conditions we obtain models of the parameters for the two groups of GLEs separately. Therefore, we establish a model of energy spectrum of solar cycle 23 GLEs which may be used in prediction in the future.Comment: 42 pages, 19 figures, 3 table

    Oscillatory instability of radiative shocks with multiple cooling processes

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    The stand-off shock formed in the accretion flow on to a stationary wall, such as the surface of a white dwarf, may be thermally unstable, depending on the cooling processes which dominate the post-shock flow. Some processes lead to instability, while others tend to stabilize the shock. We consider competition between the destabilizing influence of thermal bremsstrahlung cooling, and a stabilizing process which is a power law in density and temperature. Cyclotron cooling and processes which are of order 1, 3/2 and 2 in density are considered. The relative efficiency and power-law indices of the second mechanism are varied, and particular effects on the stability properties and frequencies of oscillation modes are examined

    Non-steroidal anti-inflammatory drugs—changes in prescribing may be warranted

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    Broadcast Gossip Algorithms for Consensus on Strongly Connected Digraphs

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    We study a general framework for broadcast gossip algorithms which use companion variables to solve the average consensus problem. Each node maintains an initial state and a companion variable. Iterative updates are performed asynchronously whereby one random node broadcasts its current state and companion variable and all other nodes receiving the broadcast update their state and companion variable. We provide conditions under which this scheme is guaranteed to converge to a consensus solution, where all nodes have the same limiting values, on any strongly connected directed graph. Under stronger conditions, which are reasonable when the underlying communication graph is undirected, we guarantee that the consensus value is equal to the average, both in expectation and in the mean-squared sense. Our analysis uses tools from non-negative matrix theory and perturbation theory. The perturbation results rely on a parameter being sufficiently small. We characterize the allowable upper bound as well as the optimal setting for the perturbation parameter as a function of the network topology, and this allows us to characterize the worst-case rate of convergence. Simulations illustrate that, in comparison to existing broadcast gossip algorithms, the approaches proposed in this paper have the advantage that they simultaneously can be guaranteed to converge to the average consensus and they converge in a small number of broadcasts.Comment: 30 pages, submitte
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