68,647 research outputs found
Generalised regression estimation given imperfectly matched auxiliary data
Generalised regression estimation allows one to make use of available
auxiliary information in survey sampling. We develop three types of generalised
regression estimator when the auxiliary data cannot be matched perfectly to the
sample units, so that the standard estimator is inapplicable. The inference
remains design-based. Consistency of the proposed estimators is either given by
construction or else can be tested given the observed sample and links. Mean
square errors can be estimated. A simulation study is used to explore the
potentials of the proposed estimators
Quark number scaling of in transverse kinetic energy and it's implications for coalescence models
We find that a simple extension of the coalescence model is sufficient to
incorporate the perfect quark number scaling behavior of the elliptic flow in
transverse kinetic energy, recently discovered by the PHENIX Collaboration. The
flavor dependence of the elliptic flow can be consistently described in the low
and intermediate if the transverse kinetic energy is conserved in the
or parton coalescence process at the hadronization. Thus
suggesting the quark coalescence as a possible hadronization mechanism at low
as well.Comment: 4 pages and 3 figures, accepted by PRC rapid comm(Added one figure
Effects of hadronic mean-field potentials on Hanbury-Brown-Twiss correlations in relativistic heavy-ion collisions
With the parameters fitted by the particle multiplicity, the energy density
at chemical freeze-out, and the charged particle elliptic flow, we have studied
the effects of the hadronic mean-field potentials on the Hanbury-Brown and
Twiss (HBT) correlation in relativistic heavy-ion collisions based on a
multiphase transport model. The hadronic mean-field potentials are found to
delay the emission time of the system and lead to large HBT radii extracted
from the correlation function. Effects on the energy dependence of
and as well as the eccentricity of the emission
source are discussed. The HBT correlations can also be useful in understanding
the mean-field potentials of protons, kaons, and antiprotons as well as
baryon-antibaryon annihilations.Comment: 9 pages, 9 figure
Light Induced Hall effect in semiconductors with spin-orbit coupling
We show that optically excited electrons by a circularly polarized light in a
semiconductor with spin-orbit coupling subject to a weak electric field will
carry a Hall current transverse to the electric field. This light induced Hall
effect is a result of quantum interference of the light and the electric field,
and can be viewed as a physical consequence of the spin current induced by the
electric field. The light induced Hall conductance is calculated for the p-type
GaAs bulk material, and the n-type and p-type quantum well structures.Comment: 5 pages, 3 figure
Minimal inference from incomplete 2x2-tables
Estimates based on 2x2 tables of frequencies are widely used in statistical
applications. However, in many cases these tables are incomplete in the sense
that the data required to compute the frequencies for a subset of the cells
defining the table are unavailable. Minimal inference addresses those
situations where this incompleteness leads to target parameters for these
tables that are interval, rather than point, identifiable. In particular, we
develop the concept of corroboration as a measure of the statistical evidence
in the observed data that is not based on likelihoods. The corroboration
function identifies the parameter values that are the hardest to refute, i.e.,
those values which, under repeated sampling, remain interval identified. This
enables us to develop a general approach to inference from incomplete 2x2
tables when the additional assumptions required to support a likelihood-based
approach cannot be sustained based on the data available. This minimal
inference approach then provides a foundation for further analysis that aims at
making sharper inference supported by plausible external beliefs
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