32,517 research outputs found
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
Effective lagrangian for a mass dimension one fermionic field in curved spacetime
In this work we use momentum-space techniques to evaluate the propagator
for a spin mass dimension one spinor field on a curved
Friedmann-Robertson-Walker spacetime. As a consequence, we built the one-loop
correction to the effective lagrangian in the coincidence limit. Going further
we compute the effective lagrangian in the finite temperature regime. We arrive
at interesting cosmological consequences, as time-dependent cosmological
`constant', fully explaining the functional form of previous cosmological
models.Comment: 9 pages, 0 figure
Chiral spin-orbital liquids with nodal lines
Strongly correlated materials with strong spin-orbit coupling hold promise
for realizing topological phases with fractionalized excitations. Here we
propose a chiral spin-orbital liquid as a stable phase of a realistic model for
heavy-element double perovskites. This spin liquid state has Majorana fermion
excitations with a gapless spectrum characterized by nodal lines along the
edges of the Brillouin zone. We show that the nodal lines are topological
defects of a non-Abelian Berry connection and that the system exhibits
dispersing surface states. We discuss some experimental signatures of this
state and compare them with properties of the spin liquid candidate Ba_2YMoO_6.Comment: 5 pages + supplementary materia
Distortion of the perfect lattice structure in bilayer graphene
We consider the instability of bilayer graphene with respect to a distorted
configuration in the same spirit as the model introduced by Su, Schrieffer and
Heeger. By computing the total energy of a distorted bilayer, we conclude that
the ground state of the system favors a finite distortion. We explore how the
equilibrium configuration changes with carrier density and an applied potential
difference between the two layers
Thrombus aspiration in patients with ST-elevation myocardial infarction: results of a national registry of interventional cardiology.
BACKGROUND:
We aimed to evaluate the impact of thrombus aspiration (TA) during primary percutaneous coronary intervention (P-PCI) in 'real-world' settings.
METHODS:
We performed a retrospective study, using data from the National Registry of Interventional Cardiology (RNCI 2006-2012, Portugal) with ST-elevation myocardial infarction (STEMI) patients treated with P-PCI. The primary outcome, in-hospital mortality, was analysed through adjusted odds ratio (aOR) and 95% confidence intervals (95%CI).
RESULTS:
We assessed data for 9458 STEMI patients that undergone P-PCI (35% treated with TA). The risk of in-hospital mortality with TA (aOR 0.93, 95%CI:0.54-1.60) was not significantly decreased. After matching patients through the propensity score, TA reduced significantly the risk of in-hospital mortality (OR 0.58, 95%CI:0.35-0.98; 3500 patients).
CONCLUSIONS:
The whole cohort data does not support the routine use of TA in P-PCI, but the results of the propensity-score matched cohort suggests that the use of selective TA may improve the short-term risks of STEMI.info:eu-repo/semantics/publishedVersio
Vortices in the presence of a nonmagnetic atom impurity in 2D XY ferromagnets
Using a model of nonmagnetic impurity potential, we have examined the
behavior of planar vortex solutions in the classical two-dimensional XY
ferromagnets in the presence of a spin vacancy localized out of the vortex
core. Our results show that a spinless atom impurity gives rise to an effective
potential that repels the vortex structure.Comment: 6 pages, 2 figures, RevTex
Disorder Induced Localized States in Graphene
We consider the electronic structure near vacancies in the half-filled
honeycomb lattice. It is shown that vacancies induce the formation of localized
states. When particle-hole symmetry is broken, localized states become
resonances close to the Fermi level. We also study the problem of a finite
density of vacancies, obtaining the electronic density of states, and
discussing the issue of electronic localization in these systems. Our results
also have relevance for the problem of disorder in d-wave superconductors.Comment: Replaced with published version. 4 pages, 4 figures. Fig. 1 was
revise
Strained graphene: tight-binding and density functional calculations
We determine the band structure of graphene under strain using density
functional calculations. The ab-initio band strucure is then used to extract
the best fit to the tight-binding hopping parameters used in a recent
microscopic model of strained graphene. It is found that the hopping parameters
may increase or decrease upon increasing strain, depending on the orientation
of the applied stress. The fitted values are compared with an available
parametrization for the dependence of the orbital overlap on the distance
separating the two carbon atoms. It is also found that strain does not induce a
gap in graphene, at least for deformations up to 10%
Population expansion in the North African Late Pleistocene signalled by mitochondrial DNA haplogroup U6
Background
<br/>
The archaeology of North Africa remains enigmatic, with questions of population continuity versus discontinuity taking centre-stage. Debates have focused on population transitions between the bearers of the Middle Palaeolithic Aterian industry and the later Upper Palaeolithic populations of the Maghreb, as well as between the late Pleistocene and Holocene.
<br/>
Results
Improved resolution of the mitochondrial DNA (mtDNA) haplogroup U6 phylogeny, by the screening of 39 new complete sequences, has enabled us to infer a signal of moderate population expansion using Bayesian coalescent methods. To ascertain the time for this expansion, we applied both a mutation rate accounting for purifying selection and one with an internal calibration based on four approximate archaeological dates: the settlement of the Canary Islands, the settlement of Sardinia and its internal population re-expansion, and the split between haplogroups U5 and U6 around the time of the first modern human settlement of the Near East.
<br/>
Conclusions
<br/>
A Bayesian skyline plot placed the main expansion in the time frame of the Late Pleistocene, around 20 ka, and spatial smoothing techniques suggested that the most probable geographic region for this demographic event was to the west of North Africa. A comparison with U6's European sister clade, U5, revealed a stronger population expansion at around this time in Europe. Also in contrast with U5, a weak signal of a recent population expansion in the last 5,000 years was observed in North Africa, pointing to a moderate impact of the late Neolithic on the local population size of the southern Mediterranean coast
Project risk management in an automotive company
The main purpose of this research project was to analyse the project risk management practices in an automotive company, in order to recommend appropriate improvements. Design/methodology/approach - The research methodology chosen to conduct the study was case study, since the research was carried out in a multinational company in the automotive industry, and data was collected through observation, document analysis and a questionnaire. Findings - Although the company has defined how to approach project risk management, it was found out that the reality experienced does not reflect what is proposed by the major references. The proposal for an approach to risk management, process by process, was well received and appreciated by the project team. Research limitations/implications - Due to the size of company, and also in some cases due to confidentiality reasons, it was not possible to obtain all the necessary data for a more accurate analysis. Additionally, due to the work routine, communication with colleagues was rarely immediate or fluid. It is also important to highlight the fact that project risk management is not an established practice within the organization. Originality/value - Risk management practices as other project management practices are context dependent and should be adapted to the situation. Other companies working with a similar context can benefit from this study and adopt similar procedures to improve their risk management practices.(undefined
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