3,965 research outputs found
Reduced attentional blink for alcohol-related stimuli in heavy social drinkers
Researchers have used various paradigms to show that attentional biases for substance-related stimuli are an important feature of addictive behaviours. However, it is not clear whether these attentional biases occur at the level of encoding or at later post-attentive processing stages. We examined attentional bias at the level of encoding with the attentional blink paradigm in a sample of non-clinical heavy and light-drinking students. Our results show a diminished attentional blink effect for alcohol-related words compared with soft drink-related words among heavy drinkers. The attentional blink was equally strong for alcohol-related and soft drink-related words among light drinkers. This suggests that alcohol-related information is processed relatively more efficiently in the former group. Even though these results are promising, our study shows that the internal consistency of the attentional blink can be improved
Alcohol approach tendencies in heavy drinkers: comparison of effects in a relevant stimulus-response compatibility task and an approach/avoidance Simon task
Several recent studies suggest that alcohol-related cues elicit automatic approach tendencies in heavy drinkers. A variety of tasks have been used to demonstrate these effects, including Relevant Stimulus-Response Compatibility (R-SRC) tasks and variants of Simon tasks. Previous work with normative stimuli suggests that the R-SRC task may be more sensitive than Simon tasks because the activation of approach tendencies may depend on encoding of the stimuli as alcohol-related, which occurs in the R-SRC task but not in Simon tasks. Our aim was to directly compare these tasks for the first time in the context of alcohol use. We administered alcohol versions of an R-SRC task and a Simon task to 62 social drinkers, who were designated as heavy or light drinkers based on a median split of their weekly alcohol consumption. Results indicated that, compared to light drinkers, heavy drinkers were faster to approach, rather than avoid, alcohol-related pictures in the R-SRC task but not in the Simon task. Theoretical implications and methodological issues are discussed
An end-to-end machine learning system for harmonic analysis of music
We present a new system for simultaneous estimation of keys, chords, and bass
notes from music audio. It makes use of a novel chromagram representation of
audio that takes perception of loudness into account. Furthermore, it is fully
based on machine learning (instead of expert knowledge), such that it is
potentially applicable to a wider range of genres as long as training data is
available. As compared to other models, the proposed system is fast and memory
efficient, while achieving state-of-the-art performance.Comment: MIREX report and preparation of Journal submissio
Hawking's chronology protection conjecture: singularity structure of the quantum stress--energy tensor
The recent renaissance of wormhole physics has led to a very disturbing
observation: If traversable wormholes exist then it appears to be rather easy
to to transform such wormholes into time machines. This extremely disturbing
state of affairs has lead Hawking to promulgate his chronology protection
conjecture. This paper continues a program begun in an earlier paper [Physical
Review {\bf D47}, 554--565 (1993), hepth@xxx/9202090]. An explicit calculation
of the vacuum expectation value of the renormalized stress--energy tensor in
wormhole spacetimes is presented. Point--splitting techniques are utilized.
Particular attention is paid to computation of the Green function [in its
Hadamard form], and the structural form of the stress-energy tensor near short
closed spacelike geodesics. Detailed comparisons with previous calculations are
presented, leading to a pleasingly unified overview of the situation.Comment: plain LaTeX, 13 page
Rapid variability of accretion in AM Herculis
We present the last pointed observation of AM Her carried out during the life
of the BeppoSAX satellite. It was bright at the beginning of the observation,
but dropped to the lowest X-ray level ever observed so far. The X-ray emission
during the bright period is consistent with accretion occurring onto the main
pole of the magnetized white dwarf. The rapid change from the active state to
the low deep state indicates a drop by a factor of 17 in the accretion rate and
hence that accretion switched-off. The short timescale (less than one hour) of
this variation still remains a puzzle. Optical photometry acquired
simultaneousy during the low state shows that the white dwarf remains heated,
although a weak emission from the accretion stream could be still present.
Cyclotron radiation, usually dominating the V and R bands, is negligible thus
corroborating the possibility that AM Her was in an off-accretion state. The
X-ray emission during the inactive state is consistent with coronal emission
from the secondary late type star.Comment: 6 pages A&A-Latex, 6 Figures, accepted for publication in A&
Drilled by the jet? XMM-Newton discovers a Compton-thick AGN in the GPS galaxy Mkn668
We report the XMM-Newton discovery of the first Compton-thick obscured AGN in
a Broad Line Radio Galaxy, the Gigahertz Peaked-Spectrum source Mkn668
(OQ+208). The remarkably flat 2-10 keV X-ray spectrum (observed photon index,
\Gamma ~ 0.7), alongside with a prominent iron K-alpha fluorescent emission
line, is a clear signature of a Compton-reflection dominated spectrum. Mkn688
represents a remarkable example of discrepancy between X-ray spectral
properties and optical classification, as its optical spectrum is characterized
by broad and asymmetric Balmer lines. The obscuring matter is constrained to be
located within the radio hotspots, in turn separated by about 10 pc. If the
jets are piercing their way through a Compton-thick medium pervading the
nuclear environment, one could be largely underestimating the radio activity
dynamical age determined from the observed hotspot recession velocity. The soft
X-ray spectrum is dominated by a much steeper component, which may be due to
nuclear continuum electron scattering, or inverse Compton of the - remarkably
large - far infrared emission. Soft X-rays are suppressed by a further
Compton-thin (N_H ~ 10^21/cm/cm) absorbing system, that we identify with matter
responsible for free-free absorption of the radio lobes.Comment: 11 pages, 7 figures, To appear in Astronomy & Astrophysic
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