32,393 research outputs found

    Asymptotic analysis of first passage time in complex networks

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    The first passage time (FPT) distribution for random walk in complex networks is calculated through an asymptotic analysis. For network with size NN and short relaxation time τ≪N\tau\ll N, the computed mean first passage time (MFPT), which is inverse of the decay rate of FPT distribution, is inversely proportional to the degree of the destination. These results are verified numerically for the paradigmatic networks with excellent agreement. We show that the range of validity of the analytical results covers networks that have short relaxation time and high mean degree, which turn out to be valid to many real networks.Comment: 6 pages, 4 figures, 1 tabl

    Flammability screening tests of resins

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    Selected flammability characteristics of glass cloth laminates of thermosetting resins are evaluated. A protocol for the evaluation of the flammability hazards presented by glass cloth laminates of thermosetting resins and the usefulness of that protocol with two laminates are presented. The glass laminates of an epoxy resin, M-751 are evaluated for: (1) determination of smoke generation from the laminates; (2) analysis of products of oxidative degradation of the laminates; (3) determination of minimum oxygen necessary to maintain flaming oxidation; (4) evaluation of toxicological hazards

    Classification of finite dimensional modules of singly atypical type over the Lie superalgebras sl(m/n)

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    We classify the finite dimensional indecomposable sl(m/n)-modules with at least a typical or singly atypical primitive weight. We do this classification not only for weight modules, but also for generalized weight modules. We obtain that such a generalized weight module is simply a module obtained by ``linking'' sub-quotient modules of generalized Kac-modules. By applying our results to sl(m/1), we have in fact completely classified all finite dimensional sl(m/1)-modules.Comment: 17 pages, Late

    Exact moments in a continuous time random walk with complete memory of its history

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    We present a continuous time generalization of a random walk with complete memory of its history [Phys. Rev. E 70, 045101(R) (2004)] and derive exact expressions for the first four moments of the distribution of displacement when the number of steps is Poisson distributed. We analyze the asymptotic behavior of the normalized third and fourth cumulants and identify new transitions in a parameter regime where the random walk exhibits superdiffusion. These transitions, which are also present in the discrete time case, arise from the memory of the process and are not reproduced by Fokker-Planck approximations to the evolution equation of this random walk.Comment: Revtex4, 10 pages, 2 figures. v2: applications discussed, clarity improved, corrected scaling of third momen

    Anomalous biased diffusion in a randomly layered medium

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    We present analytical results for the biased diffusion of particles moving under a constant force in a randomly layered medium. The influence of this medium on the particle dynamics is modeled by a piecewise constant random force. The long-time behavior of the particle position is studied in the frame of a continuous-time random walk on a semi-infinite one-dimensional lattice. We formulate the conditions for anomalous diffusion, derive the diffusion laws and analyze their dependence on the particle mass and the distribution of the random force.Comment: 19 pages, 1 figur

    Modelling substorm chorus events in terms of dispersive azimuthal drift

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    The Substorm Chorus Event (SCE) is a radio phenomenon observed on the ground after the onset of the substorm expansion phase. It consists of a band of VLF chorus with rising upper and lower cutoff frequencies. These emissions are thought to result from Doppler-shifted cyclotron resonance between whistler mode waves and energetic electrons which drift into a ground station's field of view from an injection site around midnight. The increasing frequency of the emission envelope has been attributed to the combined effects of energy dispersion due to gradient and curvature drifts, and the modification of resonance conditions and variation of the half-gyrofrequency cutoff resulting from the radial component of the <i><b>E</b></i>x<i><b>B</b></i> drift. </p><p style="line-height: 20px;"> A model is presented which accounts for the observed features of the SCE in terms of the growth rate of whistler mode waves due to anisotropy in the electron distribution. This model provides an explanation for the increasing frequency of the SCE lower cutoff, as well as reproducing the general frequency-time signature of the event. In addition, the results place some restrictions on the injected particle source distribution which might lead to a SCE.<Br><Br> <b>Key words. </b>Space plasma physics (Wave-particle interaction) – Magnetospheric physics (Plasma waves and instabilities; Storms and substorms

    Transverse Asymmetry A_T′ from the Quasielastic ^3He(e,e′) Process and the Neutron Magnetic Form Factor

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    We have measured the transverse asymmetry A_T′ in ^3He(e,e′) quasielastic scattering in Hall A at Jefferson Laboratory with high precision for Q^2 values from 0.1 to 0.6 (GeV/c)^2. The neutron magnetic form factor GMn was extracted based on Faddeev calculations for Q^2 = 0.1 and 0.2 (GeV/c)^2 with an experimental uncertainty of less than 2%

    Pushing the Margins: A Dynamic Model of Idiosyncrasy Credit in Top Management Team Behavior

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    Top management teams (TMT) behave both conventionally and unconventionally to implement strategic change in organizations. These behaviors are information used by organizational stakeholders to evaluate the TMT. However, because of limited cognitive resources, the cost of cognitive changes and the inherent variability of environments and relationships, stakeholders operate using the “latitude of norms,” which provides thresholds to measure the need for reappraisal and change. We explore this process of discontinuous reappraisals by reviewing past idiosyncratic credit literature and integrate it with expectancy violations theory to propose a theory of dynamic idiosyncratic credit. Both research and managerial implications are discussed

    First exit times and residence times for discrete random walks on finite lattices

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    In this paper, we derive explicit formulas for the surface averaged first exit time of a discrete random walk on a finite lattice. We consider a wide class of random walks and lattices, including random walks in a non-trivial potential landscape. We also compute quantities of interest for modelling surface reactions and other dynamic processes, such as the residence time in a subvolume, the joint residence time of several particles and the number of hits on a reflecting surface.Comment: 19 pages, 2 figure
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