33,989 research outputs found
Particle creation in a f(R) theory with cosmological constraints
In this paper we study the creation of super-massive real scalar particles in
the framework of a modified gravity theory, with parameters
constrained by observational data. The analysis is restrict to a homogeneous
and isotropic flat and radiation dominated universe. We compare the results to
the standard Einstein gravity with cosmological constant ( model),
and we show that the total number density of created particles in the
model is very close to the standard case. Another interesting result is that
the spectrum of created particles is independent at early times.Comment: To appear in the General Relativity and Gravitation. arXiv admin
note: text overlap with arXiv:1108.334
Fusing Audio, Textual and Visual Features for Sentiment Analysis of News Videos
This paper presents a novel approach to perform sentiment analysis of news
videos, based on the fusion of audio, textual and visual clues extracted from
their contents. The proposed approach aims at contributing to the
semiodiscoursive study regarding the construction of the ethos (identity) of
this media universe, which has become a central part of the modern-day lives of
millions of people. To achieve this goal, we apply state-of-the-art
computational methods for (1) automatic emotion recognition from facial
expressions, (2) extraction of modulations in the participants' speeches and
(3) sentiment analysis from the closed caption associated to the videos of
interest. More specifically, we compute features, such as, visual intensities
of recognized emotions, field sizes of participants, voicing probability, sound
loudness, speech fundamental frequencies and the sentiment scores (polarities)
from text sentences in the closed caption. Experimental results with a dataset
containing 520 annotated news videos from three Brazilian and one American
popular TV newscasts show that our approach achieves an accuracy of up to 84%
in the sentiments (tension levels) classification task, thus demonstrating its
high potential to be used by media analysts in several applications,
especially, in the journalistic domain.Comment: 5 pages, 1 figure, International AAAI Conference on Web and Social
Medi
In-medium formation of quarkonium
We confront preliminary RHIC data on J/Psi production in nuclear interactions
with expectations which follow in scenarios involving charm quark recombination
in a region of color deconfinement. The focus is on transverse momentum and
rapidity spectra of the J/Psi, which carry a memory of the spectra of the charm
quarks. In such a scenario, one predicts that both spectra will be narrower
than those expected without recombination. Preliminary results for the
transverse momentum spectra point toward a preference for the recombination
picture, while the rapidity spectra do not exhibit any narrowing within present
large uncertainties. We present new calculations in the recombination model for
the centrality behavior of these signals, which map out the necessary
experimental precision required for a definitive test.Comment: Based on invited talk at Strangeness in Quark Matter 2006, UCLA,
March 26-31, 2006. Clarifying remarks added in published journal versio
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