33,496 research outputs found
Three Dimensional Gauge Theory with Topological and Non-topological Mass: Hamiltonian and Lagrangian Analysis
Three dimensional (abelian) gauged massive Thirring model is bosonized in the
large fermion mass limit. A further integration of the gauge field results in a
non-local theory. A truncated version of that is the Maxwell Chern Simons (MCS)
theory with a conventional mass term or MCS Proca theory. This gauge invariant
theory is completely solved in the Hamiltonian and Lagrangian formalism, with
the spectra of the modes determined. Since the vector field constituting the
model is identified (via bosonization) to the fermion current, the charge
current algebra, including the Schwinger term is also computed in the MCS Proca
model.Comment: Eight pages, Latex, No figures
Evaluation of missing data mechanisms in two and three dimensional incomplete tables
The analysis of incomplete contingency tables is a practical and an
interesting problem. In this paper, we provide characterizations for the
various missing mechanisms of a variable in terms of response and non-response
odds for two and three dimensional incomplete tables. Log-linear
parametrization and some distinctive properties of the missing data models for
the above tables are discussed. All possible cases in which data on one, two or
all variables may be missing are considered. We study the missingness of each
variable in a model, which is more insightful for analyzing cross-classified
data than the missingness of the outcome vector. For sensitivity analysis of
the incomplete tables, we propose easily verifiable procedures to evaluate the
missing at random (MAR), missing completely at random (MCAR) and not missing at
random (NMAR) assumptions of the missing data models. These methods depend only
on joint and marginal odds computed from fully and partially observed counts in
the tables, respectively. Finally, some real-life datasets are analyzed to
illustrate our results, which are confirmed based on simulation studies
A note on the entropy of charged multi - black - holes
Majumdar--Papapetrou multi--black-hole solutions of the Einstein--Maxwell
equations are considered in four and higher dimensions. The Euclidean action
with boundary conditions appropriate to the canonical ensemble is shown to lead
to zero entropy.Comment: LaTeX, 8 page
The existence and persistence of household financial hardship
We investigate the existence and persistence of financial hardship at the household level using data from the British Household Panel Survey. Our modelling strategy makes three important contributions to the existing literature on household finances. Firstly, we model nine different types of household financial problems within a joint framework, allowing for correlation in the random effects across the nine equations. Secondly, we develop a dynamic framework in order to model the persistence of financial problems over time by extending our multi-equation framework to allow the presence or otherwise of different types of financial problems in the previous time period to influence the probability that the household currently experiences such problems. Our third contribution relates to the possibility that experiencing financial problems may be correlated with sample attrition. We model missing observations in the panel in order to allow for such attrition. Our findings reveal interesting variations in the determinants of experiencing different types of financial problems including demographic and regional differences. Our findings also highlight persistence in experiencing financial problems over time as well as the role that saving on a regular basis in previous time periods can play in mitigating current financial problems
Estimating healthcare demand for an aging population: a flexible and robust bayesian joint model
In this paper, we analyse two frequently used measures of the demand for health care, namely hospital visits and out-of-pocket health care expenditure, which have been analysed separately in the existing literature. Given that these two measures of healthcare demand are highly likely to be closely correlated, we propose a framework to jointly model hospital visits and out-of-pocket medical expenditure. Furthermore, the joint framework allows for the presence of non-linear effects of covariates using splines to capture the effects of aging on healthcare demand. Sample heterogeneity is modelled robustly with the random effects following Dirichlet process priors with explicit cross-part correlation. The findings of our empirical analysis of the U.S. Health and Retirement Survey indicate that the demand for healthcare varies with age and gender and exhibits significant cross-part correlation that provides a rich understanding of how aging affects health care demand, which is of particular policy relevance in the context of an aging population
In-medium vector mesons and low mass lepton pairs from heavy ion collisions
The rho and omega meson self-energy at finite temperature and baryon density
have been analysed for an exhaustive set of mesonic and baryonic loops in the
real time formulation of thermal field theory. The large enhancement of
spectral strength below the nominal rho mass is seen to cause a substantial
enhancement in dilepton pair yield in this mass region. The integrated yield
after space-time evolution using relativistic hydrodynamics with quark gluon
plasma in the initial state leads to a very good agreement with the
experimental data from In-In collisions obtained by the NA60 collaboration.Comment: Invited Talk at the DAE-BRNS Workshop on Hadron Physics, Bhabha
Atomic Research Centre, Mumbai, India, October 31-November 4, 201
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