21,177 research outputs found
Crossover from weak localization to weak antilocalization in a disordered microbridge
We calculate the weak localization correction in the double crossover to
broken time-reversal and spin-rotational symmetry for a disordered microbridge
or a short disordered wire using a scattering-matrix approach. Whereas the
correction has universal limiting values in the three basic symmetry classes,
the functional form of the magnetoconductance is affected by eventual
non-homogeneities in the microbridge.Comment: 5 pages, RevTeX; 2 figure
The 3D structure of the Lagrangian acceleration in turbulent flows
We report experimental results on the three dimensional Lagrangian
acceleration in highly turbulent flows. Tracer particles are tracked optically
using four silicon strip detectors from high energy physics that provide high
temporal and spatial resolution. The components of the acceleration are shown
to be statistically dependent. The probability density function (PDF) of the
acceleration magnitude is comparable to a log-normal distribution. Assuming
isotropy, a log-normal distribution of the magnitude can account for the
observed dependency of the components. The time dynamics of the acceleration
components is found to be typical of the dissipation scales whereas the
magnitude evolves over longer times, possibly close to the integral time scale.Comment: accepted for publication in Physical Review Letter
XMM-Newton observation of SNR J0533-7202 in the Large Magellanic Cloud
Aims. We present an X-ray study of the supernova remnant SNR J0533-7202 in
the Large Magellanic Cloud (LMC) and determine its physical characteristics
based on its X-ray emission. Methods. We observed SNR J0533-7202 with
XMM-Newton (flare-filtered exposure times of 18 ks EPIC-pn and 31 ks
EPIC-MOS1/MOS2). We produced X-ray images of the SNR, performed an X-ray
spectral analysis, and compared the results to multi-wavelength studies.
Results. The distribution of X-ray emission is highly non-uniform, with the
south-west region brighter than the north-east. The X-ray emission is
correlated with the radio emission from the remnant. We determine that this
morphology is likely due to the SNR expanding into a non-uniform ambient medium
and not an absorption effect. We estimate the size to be 53.9 (\pm 3.4) x 43.6
(\pm 3.4) pc, with the major axis rotated ~64 degrees east of north. We find no
spectral signatures of ejecta and infer that the X-ray plasma is dominated by
swept-up interstellar medium. Using the spectral fit results and the Sedov
self-similar solution, we estimate an age of ~17-27 kyr, with an initial
explosion energy of (0.09-0.83) x 10^51 erg. We detected an X-ray source
located near the centre of the remnant, namely XMMU J053348.2-720233. The
source type could not be conclusively determined due to the lack of a
multi-wavelength counterpart and low X-ray counts. We find that it is likely
either a background active galactic nucleus or a low-mass X-ray binary in the
LMC. Conclusions. We detected bright thermal X-ray emission from SNR J0533-7202
and determined that the remnant is in the Sedov phase of its evolution. The
lack of ejecta emission prohibits us from typing the remnant with the X-ray
data. Therefore, the likely Type Ia classification based on the local stellar
population and star formation history reported in the literature cannot be
improved upon.Comment: 7 pages, 4 figures, accepted for publication in Astronomy and
Astrophysic
Visual preference for social stimuli in individuals with autism or neurodevelopmental disorders : an eye-tracking study
Background
Recent research has identified differences in relative attention to competing social versus non-social video stimuli in individuals with autism spectrum disorder (ASD). Whether attentional allocation is influenced by the potential threat of stimuli has yet to be investigated. This is manipulated in the current study by the extent to which the stimuli are moving towards or moving past the viewer. Furthermore, little is known about whether such differences exist across other neurodevelopmental disorders. This study aims to determine if adolescents with ASD demonstrate differences in attentional allocation to competing pairs of social and non-social video stimuli, where the actor or object either moves towards or moves past the viewer, in comparison to individuals without ASD, and to determine if individuals with three genetic syndromes associated with differing social phenotypes demonstrate differences in attentional allocation to the same stimuli.
Methods
In study 1, adolescents with ASD and control participants were presented with social and non-social video stimuli in two formats (moving towards or moving past the viewer) whilst their eye movements were recorded. This paradigm was then employed with groups of individuals with fragile X, Cornelia de Lange, and Rubinstein-Taybi syndromes who were matched with one another on chronological age, global adaptive behaviour, and verbal adaptive behaviour (study 2).
Results
Adolescents with ASD demonstrated reduced looking-time to social versus non-social videos only when stimuli were moving towards them. Individuals in the three genetic syndrome groups showed similar looking-time but differences in fixation latency for social stimuli moving towards them. Across both studies, we observed within- and between-group differences in attention to social stimuli that were moving towards versus moving past the viewer.
Conclusions
Taken together, these results provide strong evidence to suggest differential visual attention to competing social versus non-social video stimuli in populations with clinically relevant, genetically mediated differences in socio-behavioural phenotypes
Heat sterilizable and impact resistant Ni-Cd battery development Quarterly report, 1 Apr. - 30 Jun. 1969
Electrochemistry, battery engineering, and impact tests of heat sterilizable nickel cadmium cell
An audit of the quality of inpatient care for adults with learning disability in the UK
OBJECTIVES: To audit patient hospital records to evaluate the performance of acute general and mental health services in delivering inpatient care to people with learning disability and explore the influence of organisational factors on the quality of care they deliver. SETTING: Nine acute general hospital Trusts and six mental health services. PARTICIPANTS: Adults with learning disability who received inpatient hospital care between May 2013 and April 2014. PRIMARY AND SECONDARY OUTCOME MEASURES: Data on seven key indicators of high-quality care were collected from 176 patients. These covered physical health/monitoring, communication and meeting needs, capacity and decision-making, discharge planning and carer involvement. The impact of services having an electronic system for flagging patients with learning disability and employing a learning disability liaison nurse was assessed. RESULTS: Indicators of physical healthcare (body mass index, swallowing assessment, epilepsy risk assessment) were poorly recorded in acute general and mental health inpatient settings. Overall, only 34 (19.3%) patients received any assessment of swallowing and 12 of the 57 with epilepsy (21.1%) had an epilepsy risk assessment. For most quality indicators, there was a non-statistically significant trend for improved performance in services with a learning disability liaison nurse. The presence of an electronic flagging system showed less evidence of benefit. CONCLUSIONS: Inpatient care for people with learning disability needs to be improved. The work gives tentative support to the role of a learning disability liaison nurse in acute general and mental health services, but further work is needed to confirm these benefits and to trial other interventions that might improve the quality and safety of care for this high-need group
Extended X-Ray Emission from QSOs
We report Chandra ACIS observations of the fields of 4 QSOs showing strong
extended optical emission-line regions. Two of these show no evidence for
significant extended X-ray emission. The remaining two fields, those of 3C
249.1 and 4C 37.43, show discrete (but resolved) X-ray sources at distances
ranging from ~10 to ~40 kpc from the nucleus. In addition, 4C 37.43 also may
show a region of diffuse X-ray emission extending out to ~65 kpc and centered
on the QSO. It has been suggested that extended emission-line regions such as
these may originate in the cooling of a hot intragroup medium. We do not detect
a general extended medium in any of our fields, and the upper limits we can
place on its presence indicate cooling times of at least a few 10^9 years. The
discrete X-ray emission sources we detect cannot be explained as the X-ray jets
frequently seen associated with radio-loud quasars, nor can they be due to
electron scattering of nuclear emission. The most plausible explanation is that
they result from high-speed shocks from galactic superwinds resulting either
from a starburst in the QSO host galaxy or from the activation of the QSO
itself. Evidence from densities and velocities found from studies of the
extended optical emission around QSOs also supports this interpretation.Comment: Accepted by ApJ. 9 pages including 5 figure
Oxygen isotope effect on the superconductivity and stripe phase in LaNdSrCuO
The oxygen isotope effect on the superconductivity, stripe phase and
structure transition is systematically investigated in
LaNdSrCuO with static stripe phase. Substitution of
O by O leads to a decrease in superconducting transition
temperature T, while enhances the temperature of the structural transition
from low-temperature-orthorhombic (LTO) phase to low-temperature-tetragonal
(LTT) phase. Compared to the Nd free sample, a larger isotope effect on
is observed in LaNdSrCuO. These results indicate
that the distortion of CuO plane suppresses the superconductivity, giving a
direct evidence for the competing of stripe phase and superconductivity because
the distortion of CuO plane enhances the stripe phase.Comment: 4 pages, 5 figure
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