7,789 research outputs found
Body image distortions following spinal cord injury
Background: Following spinal cord injury (SCI) or anaesthesia, people may continue to experience feelings of the size, shape, and posture of their body, suggesting that the conscious body image is not fully determined by immediate sensory signals. How this body image is affected by changes in sensory inputs from, and motor outputs to the body remains unclear.
Methods: We tested paraplegic and tetraplegic SCI patients on a task that yields quantitative measures of body image. Participants were presented with an anchoring stimulus on a computer screen and told to imagine that the displayed body part was part of a standing mirror image of themselves. They then identified the position on the screen, relative to the anchor, where each of several parts of their body would be located. Veridical body dimensions were identified based on measurements and photographs of participants.
Results: Compared to age-matched controls, paraplegic and tetraplegic patients alike perceived their torso and limbs as elongated relative to their body width. No effects of lesion level were found.
Conclusions: The common distortions in body image across patient groups, despite differing SCI levels, imply that a body image may be maintained despite chronic sensory and motor loss. Systematic alterations in body image follow SCI, though our results suggest these may reflect prolonged changes in body posture and wheelchair use, rather than loss of specific sensorimotor pathways. These findings provide new insight into how the body image is maintained, and may prove useful in treatments that intervene to manipulate the body image
Alice falls into a black hole: Entanglement in non-inertial frames
Two observers determine the entanglement between two free bosonic modes by
each detecting one of the modes and observing the correlations between their
measurements. We show that a state which is maximally entangled in an inertial
frame becomes less entangled if the observers are relatively accelerated. This
phenomenon, which is a consequence of the Unruh effect, shows that entanglement
is an observer-dependent quantity in non-inertial frames. In the high
acceleration limit, our results can be applied to a non-accelerated observer
falling into a black hole while the accelerated one barely escapes. If the
observer escapes with infinite acceleration, the state's distillable
entanglement vanishes.Comment: I.F-S published before with maiden name Fuentes-Guridi Replaced with
published version. Phys. Rev. Lett. in pres
2D kinematics of the edge-on spiral galaxy ESO 379-G006
We present a kinematical study of the nearly edge-on galaxy ESO 379-G006 that
shows the existence of extraplanar ionized gas. With Fabry-Perot spectroscopy
at H-alpha, we study the kinematics of ESO 379-G006 using velocity maps and
position-velocity diagrams parallel to the major and to the minor axis of the
galaxy. We build the rotation curve of the disk and discuss the role of
projection effects due to the fact of viewing this galaxy nearly edge-on. The
twisting of the isovelocities in the radial velocity field of the disk of ESO
379-G006 as well as the kinematic asymmetries found in some position-velocity
diagrams parallel to the minor axis of the galaxy suggest the existence of
deviations to circular motions in the disk that can be modeled and explained
with the inclusion of a radial inflow probably generated by a bar or by spiral
arms. We succeeded in detecting extraplanar Diffuse Ionized Gas in this galaxy.
At the same time, from the analysis of position-velocity diagrams, we found
some evidence that the extraplanar gas could lag in rotation velocity with
respect to the midplane rotation.Comment: 61 pages, 15 figures. Accepted for publication in A
A systematic framework for the design, simulation and optimization of personalized healthcare: Making and healing blood
Digital compensation of the side-band-rejection ratio in a fully analog 2SB sub-millimeter receiver
In observational radio astronomy, sideband-separating receivers are
preferred, particularly under high atmospheric noise, which is usually the case
in the sub-millimeter range. However, obtaining a good rejection ratio between
the two sidebands is difficult since, unavoidably, imbalances in the different
analog components appear. We describe a method to correct these imbalances
without making any change in the analog part of the sideband-separating
receiver, specifically, keeping the intermediate-frequency hybrid in place.
This opens the possibility of implementing the method in any existing receiver.
We have built hardware to demonstrate the validity of the method and tested it
on a fully analog receiver operating between 600 and 720GHz. We have tested the
stability of calibration and performance vs time and after full resets of the
receiver. We have performed an error analysis to compare the digital
compensation in two configurations of analog receivers, with and without
intermediate frequency (IF) hybrid. An average compensated sideband rejection
ratio of 46dB is obtained. Degradation of the compensated sideband rejection
ratio on time and after several resets of the receiver is minimal. A receiver
with an IF hybrid is more robust to systematic errors. Moreover, we have shown
that the intrinsic random errors in calibration have the same impact for
configuration without IF hybrid and for a configuration with IF hybrid with
analog rejection ratio better than 10dB. Compensated rejection ratios above
40dB are obtained even in the presence of high analog rejection. The method is
robust allowing its use under normal operational conditions at any telescope.
We also demonstrate that a full analog receiver is more robust against
systematic errors. Finally, the error bars associated to the compensated
rejection ratio are almost independent of whether IF hybrid is present or not
FACTORS CHARACTERIZING STUDENTS ATTITUDE TOWARD LEARNING SOCIAL STUDIES: AN EXPLORATORY FACTOR ANALYSIS
This paper aims to identify the factors that characterize students’ attitudes toward learning social studies. This study employed a quantitative, non-experimental research design utilizing the exploratory factor analysis technique involving 365 junior high school students in secondary school. A researcher-made instrument developed from an in-depth interview with 12 high school students, from a literature review, and related studies have been utilized. To validate the questionnaire, the researcher employs the Content Validity Ratio (CVR) method where ten (10) experts were selected to review the self-made questionnaire. Item statements that pass the threshold of 0.80 were selected as part of the survey questionnaire while those item statements which failed to reach the 0.80 thresholds were eliminated. Utilizing the Exploratory Factor Analysis (EFA), a total of 40 item statements qualified within the threshold of >0.40 after 16 rotations and iterations thus, making them the factors characterizing students’ attitudes toward learning social studies. These measures are the attitude of students in learning different areas under social studies, cognitive attitude, future academic and career planning, positive behavioral attitude, personal attitude, affective attitude, negative behavioral attitude, practical attitude, reflective attitude, and obtaining a degree in social studies. Article visualizations
The glitch activity of neutron stars
We present a statistical study of the glitch population and the behaviour of
the glitch activity across the known population of neutron stars. An unbiased
glitch database was put together based on systematic searches of radio timing
data of 898 rotation-powered pulsars obtained with the Jodrell Bank and Parkes
observatories. Glitches identified in similar searches of 5 magnetars were also
included. The database contains 384 glitches found in the rotation of 141 of
these neutron stars. We confirm that the glitch size distribution is at least
bimodal, with one sharp peak at approximately , which we
call large glitches, and a broader distribution of smaller glitches. We also
explored how the glitch activity , defined as the mean
frequency increment per unit of time due to glitches, correlates with the spin
frequency , spin-down rate , and various combinations of
these, such as energy loss rate, magnetic field, and spin-down age. It is found
that the activity is insensitive to the magnetic field and that it correlates
strongly with the energy loss rate, though magnetars deviate from the trend
defined by the rotation-powered pulsars. However, we find that a constant ratio
is consistent with the behaviour
of all rotation-powered pulsars and magnetars. This relation is dominated by
large glitches, which occur at a rate directly proportional to .
The only exception are the rotation-powered pulsars with the highest values of
, such as the Crab pulsar and PSR B054069, which exhibit a much
smaller glitch activity, intrinsically different from each other and from the
rest of the population. The activity due to small glitches also shows an
increasing trend with , but this relation is biased by selection
effects.Comment: Accepted for publication in A&
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