33,524 research outputs found
Cognitive Disease, Metabolic Disease, and Inflammation in the Honolulu Asia Aging Study: Connnecting the Dots between Insulin Resistance, Type 2 Diabetes, Alzheimer's Disease, Dementia, and Fibrinogen.
Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017
Finite-volume Hamiltonian method for coupled channel interactions in lattice QCD
Within a multi-channel formulation of scattering, we investigate the
use of the finite-volume Hamiltonian approach to resolve scattering observables
from lattice QCD spectra. The asymptotic matching of the well-known L\"uscher
formalism encodes a unique finite-volume spectrum. Nevertheless, in many
practical situations, such as coupled-channel systems, it is advantageous to
interpolate isolated lattice spectra in order to extract physical scattering
parameters. Here we study the use of the Hamiltonian framework as a
parameterisation that can be fit directly to lattice spectra. We find that with
a modest amount of lattice data, the scattering parameters can be reproduced
rather well, with only a minor degree of model dependence.Comment: 25 pages, 16 figure
Automatic estimation of flux distributions of astrophysical source populations
In astrophysics a common goal is to infer the flux distribution of
populations of scientifically interesting objects such as pulsars or
supernovae. In practice, inference for the flux distribution is often conducted
using the cumulative distribution of the number of sources detected at a given
sensitivity. The resulting "-" relationship can be used to
compare and evaluate theoretical models for source populations and their
evolution. Under restrictive assumptions the relationship should be linear. In
practice, however, when simple theoretical models fail, it is common for
astrophysicists to use prespecified piecewise linear models. This paper
proposes a methodology for estimating both the number and locations of
"breakpoints" in astrophysical source populations that extends beyond existing
work in this field. An important component of the proposed methodology is a new
interwoven EM algorithm that computes parameter estimates. It is shown that in
simple settings such estimates are asymptotically consistent despite the
complex nature of the parameter space. Through simulation studies it is
demonstrated that the proposed methodology is capable of accurately detecting
structural breaks in a variety of parameter configurations. This paper
concludes with an application of our methodology to the Chandra Deep Field
North (CDFN) data set.Comment: Published in at http://dx.doi.org/10.1214/14-AOAS750 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Quartification with T' Flavor
In the simplest (non-quiver) unified theories, fermion families are often
treated sequentially and a flavor symmetry may act similarly. As an alternative
with non-sequential flavor symmetry, we consider a model based on the group
(T'*Z_2)_global * [SU(3)^4]_local which combines the predictions of T' flavor
symmetry with the features of a unified quiver gauge theory. The model
accommodates the relationships between mixing angles separately for neutrinos,
and for quarks, which have been previously predicted with T'. This quiver
unification theory makes predictions of several additional gauge bosons and
bifundamental fermions at the TeV scale.Comment: 8 pages, LaTex; added references and clarifie
Regge approach to charged-pion photoproduction at invariant energies above 2 GeV
A Regge model with absorptive corrections is employed in a global analysis of
the world data on positive and negative pion photoproduction for photon
energies from 3 to 8 GeV. In this region resonance contributions are expected
to be negligible so that the available experimental information on differential
cross sections and single polarization observables at -t \leq 2 GeV^2 allows us
to determine the non-resonant part of the reaction amplitude reliably. The
model amplitude is then used to predict observables for photon energies below 3
GeV. Differences between our predictions and data in this energy region are
systematically examined as possible signals for the presence of excited
baryons. We find that the data available for the polarized photon asymmetry
show promising resonance signatures at invariant energies around 2 GeV. With
regard to differential cross sections the analysis of negative pion
photoproduction data, obtained recently at JLab, indicates likewise the
presence of resonance structures around 2 GeVComment: misprint in Table 3 corrected; reference adde
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