161,971 research outputs found
A measurement of energetic test electron interactions with a plasma
Interaction of energetic test electrons with dense high temperature plasma and energy dissipation distributio
Testing the Role of Technical Information in Public Risk Perception
It is widely believed that more detail about health effects and likely exposure routes is apt to reduce citizens\u27 concerns about low-probability Risks. The authors\u27 study suggests that providing such detail may not be as useful as, e.g., addressing public concerns and keeping citizens current on officials\u27 actions
Extracting forward strong amplitudes from elastic differential cross sections
The feasibility of a model-independent extraction of the forward strong
amplitude from elastic nuclear cross section data in the Coulomb-nuclear
interference region is assessed for and scattering at intermediate
energies. Theoretically-generated "data" are analyzed to provide criteria for
optimally designing experiments to measure these amplitudes, whose energy
dependence (particularly that of the real parts) is needed for disentangling
various sources of medium modifications of the projectile-nucleon interaction.
The issues considered include determining the angular region over which to make
the measurements, the role of the most forward angles measured, and the effects
of statistical and systematic errors. We find that there is a region near the
forward direction where Coulomb-nuclear interference allows reliable extraction
of the strong forward amplitude for both pions and the from .3 to 1
GeV/c.Comment: 16 pages plus 12 separate postscript figure
Surface flux pinning in superconducting amorphous (Mo0.6Ru0.4)B18
Superconducting critical current density was measured as a function of a perpendicular applied magnetic field in glassy (Mo0.6Ru0.4)82B18. The pinning force density was observed to depend linearly on 1/w, where w is the sample width measured perpendicular to both the current and field. This dependence is attributed to pinning by the sample edges. The bulk pinning contribution can be separated from the edge pinning contribution by extrapolation of the Fp vs 1/w curve. The edge contribution of the flux pinning was nearly eliminated by electrolytically polishing the sample. The contribution of the flux pinning profile due to edge pinning is analyzed in terms of the dynamic pinning model modified for edge pinning
The Effect of Non-tightness on Bayesian Estimation of PCFGs
Probabilistic context-free grammars have the unusual property of not always defining tight distributions (i.e., the sum of the “probabilities” of the trees the grammar generates can be less than one). This paper reviews how this non-tightness can arise and discusses its impact on Bayesian estimation of PCFGs. We begin by presenting the notion of “almost everywhere tight grammars ” and show that linear CFGs follow it. We then propose three different ways of reinterpreting non-tight PCFGs to make them tight, show that the Bayesian estimators in Johnson et al. (2007) are correct under one of them, and provide MCMC samplers for the other two. We conclude with a discussion of the impact of tightness empirically.
Hip-joint simulator accurately duplicates human walking pattern
Device simulates all three motions of walking and provides realistic variable loading during each step. Simulator will enable laboratory evaluation of all known types of total hip prostheses
Transition Properties of Low Lying States in Atomic Indium
We present here the results of our relativistic many-body calculations of
various properties of the first six low-lying excited states of indium. The
calculations were performed using the relativistic coupled-cluster method in
the framework of the singles, doubles and partial triples approximation. We
obtain a large lifetime ~10s for the [4p^6]5s^2 5p_{3/2} state, which had not
been known earlier. Our precise results could be used to shed light on the
reliability of the lifetime measurements of the excited states of atomic indium
that we have considered in the present work.Comment: 6 pages, 1 figure and 3 table
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