1,743 research outputs found

    Corrections and acknowledgment for ``Local limit theory and large deviations for supercritical branching processes''

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    Corrections and acknowledgment for ``Local limit theory and large deviations for supercritical branching processes'' [math.PR/0407059]Comment: Published at http://dx.doi.org/10.1214/105051606000000574 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    T. E. Harris and branching processes

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    T. E. Harris was a pioneer par excellence in many fields of probability theory. In this paper, we give a brief survey of the many fundamental contributions of Harris to the theory of branching processes, starting with his doctoral work at Princeton in the late forties and culminating in his fundamental book "The Theory of Branching Processes," published in 1963.Comment: Published in at http://dx.doi.org/10.1214/10-AOP599 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Infrared observations of P/Halley and P/Encke

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    Broadband optical/infrared photometers responding from 0.5 to 23 microns mounted on the Univ. of Minnesota (UM) O'Brien 76-cm telescope, Wyoming Infrared Observatory 234-cm telescope, and UM's Mount Lemmon Infrared Observatory 152-cm telescope were used to measure comet Halley more than 30 times between 12 Dec. 1985 to 6 May 1986. The Wyoming system was used to measure P/Encke on 24 Jul. 1987. The equipment and observations of Halley were fully described by Gehrz and Ney. Conclusions based on a preliminary analysis of the Halley and P/Encke data are reported

    Photometric observations of recent comets

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    Infrared observations of comet Bennett, Kohoutek, Bradfield, and Encke are analyzed with emphasis on the detection of the silicate emission feature. Results are summarized

    Large deviations for a damped telegraph process

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    In this paper we consider a slight generalization of the damped telegraph process in Di Crescenzo and Martinucci (2010). We prove a large deviation principle for this process and an asymptotic result for its level crossing probabilities (as the level goes to infinity). Finally we compare our results with the analogous well-known results for the standard telegraph process

    High yield fusion in a Staged Z-pinch

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    We simulate fusion in a Z-pinch; where the load is a xenon-plasma liner imploding onto a deuterium-tritium plasma target and the driver is a 2 MJ, 17 MA, 95 ns risetime pulser. The implosion system is modeled using the dynamic, 2-1/2 D, radiation-MHD code, MACH2. During implosion a shock forms in the Xe liner, transporting current and energy radially inward. After collision with the DT, a secondary shock forms pre-heating the DT to several hundred eV. Adiabatic compression leads subsequently to a fusion burn, as the target is surrounded by a flux-compressed, intense, azimuthal-magnetic field. The intense-magnetic field confines fusion α\alpha-particles, providing an additional source of ion heating that leads to target ignition. The target remains stable up to the time of ignition. Predictions are for a neutron yield of 3.0×10193.0\times 10^{19} and a thermonuclear energy of 84 MJ, that is, 42 times greater than the initial, capacitor-stored energy

    02-01 "Economic Analysis in Environmental Reviews of Trade Agreements: Assessing the North American Experience"

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    Beginning in the late 1990s, Canada and the United States began requiring "Environmental Reviews (ERs)" of all trade agreements to be negotiated by each government. This paper, commissioned by the North American Commission for Environmental Cooperation, outlines how ERs have evolved in North America, and evaluates the different methodological approaches that have been employed in ERs thus far. We show that the ERs conducted to date have an encouraging number of strengths that can be built upon. However, we also establish that the art of conducting ERs is still in its infancy. We identify four limitations with the methodological approaches that have been employed in the most recent ERs. Based on an analysis of these limitations, we propose four ways to improve how ERs are conducted in the future:

    Importance Sampling for multi-constraints rare event probability

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    Improving Importance Sampling estimators for rare event probabilities requires sharp approx- imations of the optimal density leading to a nearly zero-variance estimator. This paper presents a new way to handle the estimation of the probability of a rare event defined as a finite intersection of subset. We provide a sharp approximation of the density of long runs of a random walk condi- tioned by multiples constraints, each of them defined by an average of a function of its summands as their number tends to infinity.Comment: Conference pape

    Martin boundary of a reflected random walk on a half-space

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    The complete representation of the Martin compactification for reflected random walks on a half-space Zd×N\Z^d\times\N is obtained. It is shown that the full Martin compactification is in general not homeomorphic to the ``radial'' compactification obtained by Ney and Spitzer for the homogeneous random walks in Zd\Z^d : convergence of a sequence of points znZd1×Nz_n\in\Z^{d-1}\times\N to a point of on the Martin boundary does not imply convergence of the sequence zn/znz_n/|z_n| on the unit sphere SdS^d. Our approach relies on the large deviation properties of the scaled processes and uses Pascal's method combined with the ratio limit theorem. The existence of non-radial limits is related to non-linear optimal large deviation trajectories.Comment: 42 pages, preprint, CNRS UMR 808

    Chaos in Glassy Systems from a TAP Perspective

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    We discuss level crossing of the free-energy of TAP solutions under variations of external parameters such as magnetic field or temperature in mean-field spin-glass models that exhibit one-step Replica-Symmetry-Breaking (1RSB). We study the problem through a generalized complexity that describes the density of TAP solutions at a given value of the free-energy and a given value of the extensive quantity conjugate to the external parameter. We show that variations of the external parameter by any finite amount can induce level crossing between groups of TAP states whose free-energies are extensively different. In models with 1RSB, this means strong chaos with respect to the perturbation. The linear-response induced by extensive level crossing is self-averaging and its value matches precisely with the disorder-average of the non self-averaging anomaly computed from the 2nd moment of thermal fluctuations between low-lying, almost degenerate TAP states. We present an analytical recipe to compute the generalized complexity and test the scenario on the spherical multi-pp spin models under variation of temperature.Comment: 12 pages, 2 figure
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