28,260 research outputs found
A Note on the Stringy Embeddings of Certain N = 2 Dualities
Seiberg-Witten theory can be embedded in F-theory using D3 branes probing an
orientifold geometry. The non-perturbative corrections in the orientifold
picture map directly to the instanton corrections in the corresponding gauge
theory that convert the classical moduli space to the quantum one. In this
short review we argue that the recently proposed class of conformal Gaiotto
models may also be embedded in F-theory. The F-theory constructions help us not
only to understand the Gaiotto dualities but also to extend to the
non-conformal cases with and without cascading behaviors. For the conformal
cases, the near horizon geometries in F-theory capture both the UV and IR
behaviors succinctly.Comment: 6 pages, LaTeX, Based on the talk given by K. D at the Theory Canada
Conference June 2012; v2: Typos corrected and references adde
Galaxy Bias and its Effects on the Baryon Acoustic Oscillations Measurements
The baryon acoustic oscillation (BAO) feature in the clustering of matter in
the universe serves as a robust standard ruler and hence can be used to map the
expansion history of the universe. We use high force resolution simulations to
analyze the effects of galaxy bias on the measurements of the BAO signal. We
apply a variety of Halo Occupation Distributions (HODs) and produce biased mass
tracers to mimic different galaxy populations. We investigate whether galaxy
bias changes the non-linear shifts on the acoustic scale relative to the
underlying dark matter distribution presented by Seo et al (2009). For the less
biased HOD models (b < 3), we do not detect any shift in the acoustic scale
relative to the no-bias case, typically 0.10% \pm 0.10%. However, the most
biased HOD models (b > 3) show a shift at moderate significance (0.79% \pm
0.31% for the most extreme case). We test the one-step reconstruction technique
introduced by Eisenstein et al. (2007) in the case of realistic galaxy bias and
shot noise. The reconstruction scheme increases the correlation between the
initial and final (z = 1) density fields achieving an equivalent level of
correlation at nearly twice the wavenumber after reconstruction. Reconstruction
reduces the shifts and errors on the shifts. We find that after reconstruction
the shifts from the galaxy cases and the dark matter case are consistent with
each other and with no shift. The 1-sigma systematic errors on the distance
measurements inferred from our BAO measurements with various HODs after
reconstruction are about 0.07% - 0.15%.Comment: Accepted by ApJ. 21 pages, 10 figure
Online Forum Thread Retrieval using Pseudo Cluster Selection and Voting Techniques
Online forums facilitate knowledge seeking and sharing on the Web. However,
the shared knowledge is not fully utilized due to information overload. Thread
retrieval is one method to overcome information overload. In this paper, we
propose a model that combines two existing approaches: the Pseudo Cluster
Selection and the Voting Techniques. In both, a retrieval system first scores a
list of messages and then ranks threads by aggregating their scored messages.
They differ on what and how to aggregate. The pseudo cluster selection focuses
on input, while voting techniques focus on the aggregation method. Our combined
models focus on the input and the aggregation methods. The result shows that
some combined models are statistically superior to baseline methods.Comment: The original publication is available at
http://www.springerlink.com/. arXiv admin note: substantial text overlap with
arXiv:1212.533
Formulating the Net Gain of MISO-SFN in the Presence of Self-Interferences
In this study, an analytical formula for multiple-input single-output single frequency network gain (MISO-SFNG) is investigated. To formulate the net MISO-SFNG, we derived the average signal to interference plus noise ratio (SINR) where the gain achieved by the distributed MISO diversity as a function of power imbalance is curve-fitted. Further, we analyzed the losses owing to self-interferences resulting from the delay spread and imperfect channel estimation. We verified the accuracy and effectiveness of the derived formula by comparing the measurement results with the analytical results. The derived formula helps to understand how various system factors affect the gain under a given condition. The formula can be used to evaluate the MISO-SFNG and to predict the MISO-SFN coverage in various system configurations
Of mice and men: Sparse statistical modeling in cardiovascular genomics
In high-throughput genomics, large-scale designed experiments are becoming
common, and analysis approaches based on highly multivariate regression and
anova concepts are key tools. Shrinkage models of one form or another can
provide comprehensive approaches to the problems of simultaneous inference that
involve implicit multiple comparisons over the many, many parameters
representing effects of design factors and covariates. We use such approaches
here in a study of cardiovascular genomics. The primary experimental context
concerns a carefully designed, and rich, gene expression study focused on
gene-environment interactions, with the goals of identifying genes implicated
in connection with disease states and known risk factors, and in generating
expression signatures as proxies for such risk factors. A coupled exploratory
analysis investigates cross-species extrapolation of gene expression
signatures--how these mouse-model signatures translate to humans. The latter
involves exploration of sparse latent factor analysis of human observational
data and of how it relates to projected risk signatures derived in the animal
models. The study also highlights a range of applied statistical and genomic
data analysis issues, including model specification, computational questions
and model-based correction of experimental artifacts in DNA microarray data.Comment: Published at http://dx.doi.org/10.1214/07-AOAS110 in the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Constraint on the solar using 4,000 days of short baseline reactor neutrino data
There is a well known 2 tension in the measurements of the solar
between KamLAND and SNO/Super-KamioKANDE. Precise determination of
the solar is especially important in connection with current and
future long baseline CP violation measurements. Reference \cite{Seo:2018rrb}
points out that currently running short baseline reactor neutrino experiments,
Daya Bay and RENO, can also constrain solar value as demonstrated
by a GLoBES simulation with a limited systematic uncertainty consideration. In
this work, the publicly available data, from Daya Bay (1,958 days) and RENO
(2,200 days) are used to constrain the solar . Verification of our
method through and measurements is
discussed in Appendix A. Using this verified method, reasonable constraints on
the solar are obtained using above Daya Bay and RENO data, both
individually and combined. We find that the combined data of Daya Bay and RENO
set an upper limit on the solar of 18 eV at
the 95% C.L., including both systematic and statistical uncertainties. This
constraint is slightly more than twice the KamLAND value. As this combined
result is still statistics limited, even though driven by Daya Bay data, the
constraint will improve with the additional running of this experiment.Comment: 8 pages, 6 figures, 2 tables. This paper is a follow up of a Monte
Carlo study reported in arXiv:1808.09150 by two of the authors. The current
paper uses actual data from Daya Bay and RENO that was not previously
available and this is the 1st "combined" result using this new experimental
data. A new figure is added. Some modifications of the tex
- …