262 research outputs found
Atypical emotional anticipation in high-functioning autism
"Background: Understanding and anticipating others’ mental or emotional states relies on the processing of social
cues, such as dynamic facial expressions. Individuals with high-functioning autism (HFA) may process these cues
differently from individuals with typical development (TD) and purportedly use a ‘mechanistic’ rather than a
‘mentalistic’ approach, involving rule- and contingency-based interpretations of the stimuli. The study primarily
aimed at examining whether the judgments of facial expressions made by individuals with TD and HFA would be
similarly affected by the immediately preceding dynamic perceptual history of that face. A second aim was to
explore possible differences in the mechanisms underpinning the perceptual judgments in the two groups.
Methods: Twenty-two adults with HFA and with TD, matched for age, gender and IQ, were tested in three
experiments in which dynamic, ‘ecologically valid’ offsets of happy and angry facial expressions were presented.
Participants evaluated the expression depicted in the last frame of the video clip by using a 5-point scale ranging
from slightly angry via neutral to slightly happy. Specific experimental manipulations prior to the final facial
expression of the video clip allowed examining contributions of bottom-up mechanisms (sequential contrast/
context effects and representational momentum) and a top-down mechanism (emotional anticipation) to
distortions in the perception of the final expression.
Results: In experiment 1, the two groups showed a very similar perceptual bias for the final expression of joy-to-neutral
and anger-to-neutral videos (overshoot bias). In experiment 2, a change in the actor’s identity during the clip removed
the bias in the TD group, but not in the HFA group. In experiment 3, neutral-to-joy/anger-to-neutral sequences generated
an undershoot bias (opposite to the overshoot) in the TD group, whereas no bias was observed in the HFA group.
Conclusions: We argue that in TD individuals the perceptual judgments of other’s facial expressions were underpinned
by an automatic emotional anticipation mechanism. In contrast, HFA individuals were primarily influenced by visual
features, most notably the contrast between the start and end expressions, or pattern extrapolation. We critically discuss
the proposition that automatic emotional anticipation may be induced by motor simulation of the perceived dynamic
facial expressions and discuss its implications for autism.
Polarisation Observations of VY Canis Majoris Water Vapour 5{32}-4{41} 620.701 GHz Maser Emission with HIFI
CONTEXT: Water vapour maser emission from evolved oxygen-rich stars remains
poorly understood. Additional observations, including polarisation studies and
simultaneous observation of different maser transitions may ultimately lead to
greater insight. AIMS: We have aimed to elucidate the nature and structure of
the VY CMa water vapour masers in part by observationally testing a theoretical
prediction of the relative strengths of the 620.701 GHz and the 22.235 GHz
maser components of ortho water vapour. METHODS: In its high-resolution mode
(HRS) the Herschel Heterodyne Instrument for the Infrared (HIFI) offers a
frequency resolution of 0.125 MHz, corresponding to a line-of-sight velocity of
0.06 km/s, which we employed to obtain the strength and linear polarisation of
maser spikes in the spectrum of VY CMa at 620.701 GHz. Simultaneous ground
based observations of the 22.235 GHz maser with the Max-Planck-Institut f\"ur
Radioastronomie 100-meter telescope at Effelsberg, provided a ratio of 620.701
GHz to 22.235 GHz emission. RESULTS:We report the first astronomical detection
to date of water vapour maser emission at 620.701 GHz. In VY CMa both the
620.701 and the 22.235 GHz polarisation are weak. At 620.701 GHz the maser
peaks are superposed on what appears to be a broad emission component, jointly
ejected asymmetrically from the star. We observed the 620.701 GHz emission at
two epochs 21 days apart, both to measure the potential direction of linearly
polarised maser components and to obtain a measure of the longevity of these
components. Although we do not detect significant polarisation levels in the
core of the line, they rise up to approximately 6% in its wings
Discovery of water vapour in the carbon star V Cygni from observations with Herschel/HIFI
We report the discovery of water vapour toward the carbon star V Cygni. We
have used Herschel's HIFI instrument, in dual beam switch mode, to observe the
1(11) - 0(00) para-water transition at 1113.3430 GHz in the upper sideband of
the Band 4b receiver. The observed spectral line profile is nearly parabolic,
but with a slight asymmetry associated with blueshifted absorption, and the
integrated antenna temperature is 1.69 \pm 0.17 K km/s. This detection of
thermal water vapour emission, carried out as part of a small survey of water
in carbon-rich stars, is only the second such detection toward a carbon-rich
AGB star, the first having been obtained by the Submillimeter Wave Astronomy
Satellite toward IRC+10216. For an assumed ortho-to-para ratio of 3 for water,
the observed line intensity implies a water outflow rate ~ (3 - 6) E-5 Earth
masses per year and a water abundance relative to H2 of ~ (2-5) E-6. This value
is a factor of at least 1E+4 larger than the expected photospheric abundance in
a carbon-rich environment, and - as in IRC+10216 - raises the intriguing
possibility that the observed water is produced by the vapourisation of
orbiting comets or dwarf planets. However, observations of the single line
observed to date do not permit us to place strong constraints upon the spatial
distribution or origin of the observed water, but future observations of
additional transitions will allow us to determine the inner radius of the
H2O-emitting zone, and the H2O ortho-to-para ratio, and thereby to place
important constraints upon the origin of the observed water emission.Comment: Accepted for publication in A&A (HIFI special issue
Risk of Intracranial Complications in Minor Head Injury:The Role of Loss of Consciousness and Post-Traumatic Amnesia in a Multi-Center Observational Study
Various guidelines for minor head injury focus on patients with a Glasgow Coma Scale (GCS) score of 13-15 and loss of consciousness (LOC) or post-traumatic amnesia (PTA), while clinical management for patients without LOC or PTA is often unclear. We aimed to investigate the effect of presence and absence of LOC or PTA on intracranial complications in minor head injury. A prospective multi-center cohort study of all patients with blunt head injury and GCS score of 15 was conducted at six Dutch centers between 2015 and 2017. Five centers used the national guideline and one center used a local guideline-both based on the CT in Head Injury Patients (CHIP) prediction model-to identify patients in need of a computed tomography (CT) scan. We studied the presence of traumatic findings and neurosurgical interventions in patients with and without LOC or PTA. In addition, we assessed the association of LOC and PTA with traumatic findings with logistic regression analysis and the additional predictive value of LOC and PTA compared with other risk factors in the CHIP model. Of 3914 patients, 2249 (58%) experienced neither LOC nor PTA and in 305 (8%) LOC and PTA was unknown. Traumatic findings were present in 153 of 1360 patients (11%) with LOC or PTA and in 67 of 2249 patients (3%) without LOC and PTA. Five patients without LOC and PTA had potential neurosurgical lesions and one patient underwent a neurosurgical intervention. LOC and PTA were strongly associated with traumatic findings on CT, with adjusted odds ratios of 2.9 (95% confidence interval [CI] 2.2-3.8) and 3.5 (95% CI 2.7-4.6), respectively. To conclude, patients who had minor head injury with neither LOC nor PTA are at risk of intracranial complications. Clinical guidelines should include clinical management for patients without LOC and PTA, and they should include LOC and PTA as separate risk factors rather than as diagnostic selection criteria
Addendum to the Dutch guideline for minor head/brain injury
- After introduction of the Dutch guideline for 'Care for patients with minor head/brain injury' (LTH guideline) in 2010, the number of CT scans has increased. Some of these scans were for patients with only trivial trauma and may not have been necessary.- In addition, since this guideline was implemented, there have been changes in the use of anticoagulants and platelet aggregation inhibitors. Non-vitamin-K-dependent oral anticoagulants (NOACs) and platelet aggregation inhibitors, or combinations of these, are prescribed more often.- These two factors have led the Netherlands Society of Neurology to initiate a request for modification of the LTH guideline for adults in two ways: (a) identification of minimal or trivial trauma for which no CT scan is required and (b) inclusion of NOACs and platelet aggregation inhibitors, or combinations of these, in the guideline.</p
Hydrides in Young Stellar Objects: Radiation tracers in a protostar-disk-outflow system
Context: Hydrides of the most abundant heavier elements are fundamental
molecules in cosmic chemistry. Some of them trace gas irradiated by UV or
X-rays. Aims: We explore the abundances of major hydrides in W3 IRS5, a
prototypical region of high-mass star formation. Methods: W3 IRS5 was observed
by HIFI on the Herschel Space Observatory with deep integration (about 2500 s)
in 8 spectral regions. Results: The target lines including CH, NH, H3O+, and
the new molecules SH+, H2O+, and OH+ are detected. The H2O+ and OH+ J=1-0 lines
are found mostly in absorption, but also appear to exhibit weak emission
(P-Cyg-like). Emission requires high density, thus originates most likely near
the protostar. This is corroborated by the absence of line shifts relative to
the young stellar object (YSO). In addition, H2O+ and OH+ also contain strong
absorption components at a velocity shifted relative to W3 IRS5, which are
attributed to foreground clouds. Conclusions: The molecular column densities
derived from observations correlate well with the predictions of a model that
assumes the main emission region is in outflow walls, heated and irradiated by
protostellar UV radiation.Comment: Astronomy and Astrophysics Letters, in pres
Sensitive limits on the abundance of cold water vapor in the DM Tau protoplanetary disk
We performed a sensitive search for the ground-state emission lines of ortho-
and para-water vapor in the DM Tau protoplanetary disk using the Herschel/HIFI
instrument. No strong lines are detected down to 3sigma levels in 0.5 km/s
channels of 4.2 mK for the 1_{10}--1_{01} line and 12.6 mK for the
1_{11}--0_{00} line. We report a very tentative detection, however, of the
1_{10}--1_{01} line in the Wide Band Spectrometer, with a strength of
T_{mb}=2.7 mK, a width of 5.6 km/s and an integrated intensity of 16.0 mK km/s.
The latter constitutes a 6sigma detection. Regardless of the reality of this
tentative detection, model calculations indicate that our sensitive limits on
the line strengths preclude efficient desorption of water in the UV illuminated
regions of the disk. We hypothesize that more than 95-99% of the water ice is
locked up in coagulated grains that have settled to the midplane.Comment: 5 pages, 3 figures. Accepted for publication in the Herschel HIFI
special issue of A&
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