169,370 research outputs found
Prior elicitation in Bayesian quantile regression for longitudinal data
© 2011 Alhamzawi R, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original auhor and source are credited.This article has been made available through the Brunel Open Access Publishing Fund.In this paper, we introduce Bayesian quantile regression for longitudinal data in terms of informative priors and Gibbs sampling. We develop methods for eliciting prior distribution to incorporate historical data gathered from similar previous studies. The methods can be used either with no prior data or with complete prior data. The advantage of the methods is that the prior distribution is changing automatically when we change the quantile. We propose Gibbs sampling methods which are computationally efficient and easy to implement. The methods are illustrated with both simulation and real data.This article is made available through the Brunel Open Access Publishing Fund
On aether terms in a space-time with a compact extra dimension
In this paper, for the CPT-even and CPT-odd extensions of the QED, we
explicitly obtain the aether-like corrections for the electromagnetic field in
the case when the space-time involves an extra compact spatial dimension
besides of usual four dimensions. Our methodology is based on an explicit
summation over the Kaluza-Klein tower of fields which is no more difficult than
the finite-temperature calculations. The quantum corrections turn out to be
large as the extra dimension is small. We demonstrate that in the CPT-even
case, the extra dimension manifests itself through a new scalar particle.Comment: 9 page
Metallic and semi-metallic <100> silicon nanowires
Silicon nanowires grown along the -direction with a bulk Si core are
studied with density functional calculations. Two surface reconstructions
prevail after exploration of a large fraction of the phase space of nanowire
reconstructions. Despite their energetical equivalence, one of the
reconstructions is found to be strongly metallic while the other one is
semi-metallic. This electronic-structure behavior is dictated by the particular
surface states of each reconstruction. These results imply that doping is not
required in order to obtain good conducting Si nanowires.Comment: 13 pages, 4 figures; Phys. Rev. Lett., in pres
On the Adler-Bell-Jackiw anomaly in a Horava-Lifshitz-like QED
We show the absence of the ABJ anomaly for the Horava-Lifshitz-like QED with
any even . Besides of this, we study the graph contributing to the ABJ
anomaly at non-zero temperature and extend the Fujikawa's methodology of
studying the integral measure for our model.Comment: 9 pages, version accepted to EP
On the perturbative generation of the higher-derivative Lorentz-breaking terms
In this paper, we describe the perturbative generation of the
higher-derivative Lorentz-breaking terms for the gauge field, that is, the
Myers-Pospelov term and the higher-derivative Carroll-Field-Jackiw term. These
terms are explicitly calculated in the one-loop approximation and shown to be
finite and ambiguous.Comment: 12 pages, version accepted to PR
Inviscid transonic flow computations with shock fitting
First-and second-order numerical procedures are presented for calculating two-dimensional transonic flows that treat shock waves as discontinuities. Their application to a simple but nontrivial problem for which there are limited theoretical results is discussed
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