26,102 research outputs found
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Many Californians With Asthma Have Problems Understanding Their Doctor
Examines the prevalence and consequences of communication problems with doctors among adult asthma patients by education, income, insurance status, English proficiency, race/ethnicity, and nativity. Recommends customized education materials and programs
Performance Limits of Stochastic Sub-Gradient Learning, Part II: Multi-Agent Case
The analysis in Part I revealed interesting properties for subgradient
learning algorithms in the context of stochastic optimization when gradient
noise is present. These algorithms are used when the risk functions are
non-smooth and involve non-differentiable components. They have been long
recognized as being slow converging methods. However, it was revealed in Part I
that the rate of convergence becomes linear for stochastic optimization
problems, with the error iterate converging at an exponential rate
to within an neighborhood of the optimizer, for some and small step-size . The conclusion was established under weaker
assumptions than the prior literature and, moreover, several important problems
(such as LASSO, SVM, and Total Variation) were shown to satisfy these weaker
assumptions automatically (but not the previously used conditions from the
literature). These results revealed that sub-gradient learning methods have
more favorable behavior than originally thought when used to enable continuous
adaptation and learning. The results of Part I were exclusive to single-agent
adaptation. The purpose of the current Part II is to examine the implications
of these discoveries when a collection of networked agents employs subgradient
learning as their cooperative mechanism. The analysis will show that, despite
the coupled dynamics that arises in a networked scenario, the agents are still
able to attain linear convergence in the stochastic case; they are also able to
reach agreement within of the optimizer
Charged Black Holes with Scalar Hair
We consider a class of Einstein-Maxwell-Dilaton theories, in which the
dilaton coupling to the Maxwell field is not the usual single exponential
function, but one with a stationary point. The theories admit two charged black
holes: one is the Reissner-Nordstr{\o}m (RN) black hole and the other has a
varying dilaton. For a given charge, the new black hole in the extremal limit
has the same AdSSphere near-horizon geometry as the RN black hole,
but it carries larger mass. We then introduce some scalar potentials and obtain
exact charged AdS black holes. We also generalize the results to black
-branes with scalar hair.Comment: Latex, 22 pages, typos corrected and references added, to appear in
JHE
The Redshift-Space Cluster-Galaxy Cross-Correlation Function: I. Modeling Galaxy Infall onto Millennium Simulation Clusters and SDSS Groups
The large scale infall of galaxies around massive clusters provides a
potentially powerful diagnostic of structure growth, dark energy, and
cosmological deviations from General Relativity. We develop and test a method
to recover galaxy infall kinematics (GIK) from measurements of the
redshift-space cluster-galaxy cross-correlation function \xi_{cg}(r_p,r_\pi).
Using galaxy and halo samples from the Millennium simulation, we calibrate an
analytic model of the galaxy kinematic profiles comprised of a virialized
component with an isotropic Gaussian velocity distribution and an infall
component described by a skewed 2D t-distribution with a characteristic infall
velocity v_r and separate radial and tangential dispersions. We show that
convolving the real-space cross-correlation function with this velocity
distribution accurately predicts the redshift-space \xi_{cg}, and we show that
measurements of \xi_{cg} can be inverted to recover the four distinct elements
of the GIK profiles. These in turn provide diagnostics of cluster mass
profiles, and we expect the characteristic infall velocity v_r(r) in particular
to be insensitive to galaxy formation physics that can affect velocity
dispersions within halos. As a proof of concept we measure \xi_{cg} for rich
galaxy groups in the Sloan Digital Sky Survey and recover GIK profiles for
groups in two bins of central galaxy stellar mass. The higher mass bin has a
v_r(r) curve very similar to that of 10^{14} Msun halos in the Millennium
simulation, and the recovered kinematics follow the expected trends with mass.
GIK modeling of cluster-galaxy cross-correlations can be a valuable complement
to stacked weak lensing analyses, allowing novel tests of modified gravity
theories that seek to explain cosmic acceleration.Comment: Matched to the published version (adding one figure illustrating the
position and velocity vectors). For a brief video explaining the key result
of this paper, see https://www.youtube.com/watch?v=7RB49odfSGo, or
http://v.youku.com/v_show/id_XNDcxMDY3MTQ0.html in countries where YouTube is
not accessibl
SU(2)-Colored (A)dS Black Holes in Conformal Gravity
We consider four-dimensional conformal gravity coupled to the U(1) Maxwell
and SU(2) Yang-Mills fields. We study the structure of general black hole
solutions carrying five independent parameters: the mass, the electric U(1) and
magnetic SU(2) charges, the massive spin-2 charge and the thermodynamical
pressure associated with the cosmological constant, which is an integration
constant in conformal gravity. We derive the thermodynamical first law of the
black holes. We obtain some exact solutions including an extremal black hole
with vanishing mass and entropy, but with non-trivial SU(2) Yang-Mills charges.
We derive the remainder of the first law for this special solution. We also
reexamine the colored black holes and derive their first law in
Einstein-Yang-Mills gravity with or without a cosmological constant.Comment: Latex, 22 pages, typos corrected and references adde
Charged Black Holes in Colored Lifshitz Spacetimes
We consider Einstein gravities coupled to a cosmological constant and
Yang-Mills fields in four and five dimensions. We find that the theories admit
colored Lifshitz solutions with dynamic exponents . We study the wave
equations of the scalar triplet in the bulk, and find that the vacuum
color modifies the scaling dimensions of the dual operators. We also introduce
a Maxwell field and construct exact solutions of electrically-charged black
holes that asymptote to the , and , colored Lifshitz
spacetimes. We derive the thermodynamical first law for general colored and
charged Lifshitz black holes.Comment: Latex, 13 pages, minor corrections and references adde
Electrically-Charged Lifshitz Spacetimes, and Hyperscaling Violations
Electrically-charged Lifshitz spacetimes are hard to come by. In this paper,
we construct a class of such solutions in five dimensional Einstein gravity
coupled to Maxwell and Yang-Mills fields. The solutions are
electrically-charged under the Maxwell field, whose equation is sourced by the
Yang-Mills instanton(-like) configuration living in the hyperbolic four-space
of the Lifshitz spacetime. We then introduce a dilaton and construct charged
and colored Lifshitz spacetimes with hyperscaling violations. We obtain a class
of exact Lifshitz black holes. We also perform similar constructions in four
dimensions.Comment: Latex, 14 page
Heavy Higgs Bosons at 14 TeV and 100 TeV
Searching for Higgs bosons beyond the Standard Model (BSM) is one of the most
important missions for hadron colliders. As a landmark of BSM physics, the MSSM
Higgs sector at the LHC is expected to be tested up to the scale of the
decoupling limit of O(1) TeV, except for a wedge region centered around
, which has been known to be difficult to probe. In this
article, we present a dedicated study testing the decoupled MSSM Higgs sector,
at the LHC and a next-generation -collider, proposing to search in channels
with associated Higgs productions, with the neutral and charged Higgs further
decaying into and , respectively. In the case of neutral Higgs we are
able to probe for the so far uncovered wedge region via . Additionally, we cover the the high range with . The combination of these searches with channels dedicated to
the low region, such as and potentially covers the full range. The search for charged
Higgs has a slightly smaller sensitivity for the moderate region,
but additionally probes for the higher and lower regions with even
greater sensitivity, via . While the LHC will be able
to probe the whole range for Higgs masses of O(1) TeV by combining
these channels, we show that a future 100 TeV -collider has a potential to
push the sensitivity reach up to TeV. In order to deal
with the novel kinematics of top quarks produced by heavy Higgs decays, the
multivariate Boosted Decision Tree (BDT) method is applied in our collider
analyses. The BDT-based tagging efficiencies of both hadronic and leptonic
top-jets, and their mutual fake rates as well as the faking rates by other jets
(, , , , etc.) are also presented.Comment: published versio
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