3,798 research outputs found
Motor kinematic differences in children with autism sepectrum disorder : ecological gameplay with a sensorised toy
Background Evidence suggests gross motor differences are present in children with Autism Spectrum Disorder (ASD) from birth. Trevarthen and Delafield-Butt (2013) proposed that one of the early markers of ASD are abnormalities in the development of intentional movements, which are present before the manifestations of symptoms typically associated with autism, like deficiencies in social interaction and communication. A growing body of literature demonstrates kinematic and action patterns differences in children and adults with ASD. However, these experiments typically require expensive laboratory-based optical motion tracking systems. Here, we developed bespoke, sensorised wooden cubes for motor assessment of children’s play and report on the kinematic and action pattern differences of the children with autism compared to children developing typically. Objectives A description of ASD-specific action patterns and kinematics using sensorised toys. Methods Participants. Children 3 to 5 years diagnosed with ASD (n = 15) recruited from the Scottish Centre for Autism, Glasgow, UK. Children 3 to 5 years old developing typically recruited from nurseries in Glasgow, UK. Adults 20 to 25 years old without ASD recruited from Glasgow, UK. The study was approved by the University of Strathclyde Ethics Committee and consent obtained from the parents of children or the adults. In the case of the children with ASD, pre-screening with Vineland-II, AQ-Child and Leiter-R Brief IQ was performed. Procedure. The children were seated at a table and instructed to play two simple games that involved moving the cube from one position to another: a Serially Organized Action (SOA) game and a Single Repetitive Action (SRA) game. The first required complex motor sequencing and engagement with the experimenter, while the second consisted of a simple repetitive movement. Each game produced a single measured movement to a goal with 25 iterations or repetitions to yield 50 movements in total. An electronic board inside the cubes was equipped with tri-axial magnetometer, gyroscope and accelerometer wirelessly transferred the cube’s motion data to a laptop. The signal (raw motion data) was extracted through a Matlab-based platform and analysed. Data Analysis. Kinematic features of movement duration; maximum value of acceleration, velocity, and jerk during each movement; time to maximum value; % duration to maximum value; and the acceleration, velocity, and jerk action patterns profiles were calculated. Results The jerk profile of children with ASD was significantly different, showing increased maximum jerk, reduced time to maximum value and & duration to maximum value, and lower variability than typically developing children. Further, movement duration was shorter compared to age-matched typically developing children, and maximum velocity was significantly higher in children with ASD compared to children developing typically. Conclusion The increased jerk values and onset times in the ASD group are a particularly interesting finding that support new data appearing by other groups. It appeared, especially in the SRA game, that when moving the cube from one position to the next, the children with autism impacted on the surface of the table with greater velocity and typically included the resulting force immediately into to the next movement, giving it a greater jerk value in a shorter span of time that typically children. Typically developing children, on the other hand, paused for a moment (>100 ms) before commencing the next movement. Further, children with autism did not enjoy the SRA game, but they did enjoy the simpler, more repetitive SOA one. The repetitive simplicity of the SOA game and its resulting jerk profile appears to report on a particular behavioural motor feature distinct to ASD, namely stopping an action and starting a new one, while also describing an underlying motor difference that may contribute to it
Essential nonlinearities in hearing
Our hearing organ, the cochlea, evidently poises itself at a Hopf bifurcation
to maximize tuning and amplification. We show that in this condition several
effects are expected to be generic: compression of the dynamic range,
infinitely shrap tuning at zero input, and generation of combination tones.
These effects are "essentially" nonlinear in that they become more marked the
smaller the forcing: there is no audible sound soft enough not to evoke them.
All the well-documented nonlinear aspects of hearing therefore appear to be
consequences of the same underlying mechanism.Comment: 4 pages, 3 figure
An enhanced CRISPR repressor for targeted mammalian gene regulation.
The RNA-guided endonuclease Cas9 can be converted into a programmable transcriptional repressor, but inefficiencies in target-gene silencing have limited its utility. Here we describe an improved Cas9 repressor based on the C-terminal fusion of a rationally designed bipartite repressor domain, KRAB-MeCP2, to nuclease-dead Cas9. We demonstrate the system's superiority in silencing coding and noncoding genes, simultaneously repressing a series of target genes, improving the results of single and dual guide RNA library screens, and enabling new architectures of synthetic genetic circuits
Polarization of Dust Emission in Clumpy Molecular Clouds and Cores
Grain alignment theory has reached the stage where quantitative predictions
of the degree of alignment and its variations with optical depth are possible.
With the goal of studying the effect of clumpiness on the sub-millimeter and
far infrared polarization we computed the polarization due to alignment via
radiative torques within clumpy models of cores and molecular clouds. Our
models were based upon a highly inhomogeneous simulation of compressible
magnetohydrodynamic turbulence. The P-I relations for our models reproduce
those seen in observations. We show that the degree of polarization observed is
extremely sensitive to the upper grain size cut-off, and is less sensitive to
changes in the radiative anisotropy. Furthermore, despite a variety of dust
temperatures along a single line of sight through our core and amongst dust
grains of different sizes, the assumption of isothermality amongst the aligned
grains does not introduce a significant error. Our calculations indicate that
sub-mm polarization vectors can be reasonably good tracers for the underlying
magnetic field structure, even for relatively dense clouds (A_V~10 to the cloud
center).
The current predictive power of the grain alignment theory should motivate
future polarization observations using the next generation of multi-wavelength
sub-mm polarimeters such as those proposed for SOFIA.Comment: 39 pages. 15 figures. Submitted to Ap
A scenario of planet erosion by coronal radiation
Context: According to theory, high-energy emission from the coronae of cool
stars can severely erode the atmospheres of orbiting planets. No observational
tests of the long term effects of erosion have yet been made. Aims: To analyze
the current distribution of planetary mass with X-ray irradiation of the
atmospheres in order to make an observational assessment of the effects of
erosion by coronal radiation. Methods: We study a large sample of
planet-hosting stars with XMM-Newton, Chandra and ROSAT; make a careful
identification of X-ray counterparts; and fit their spectra to make accurately
measurements of the stellar X-ray flux. Results: The distribution of the
planetary masses with X-ray flux suggests that erosion has taken place: most
surviving massive planets, (M_p sin i >1.5 M_J), have been exposed to lower
accumulated irradiation. Heavy erosion during the initial stages of stellar
evolution is followed by a phase of much weaker erosion. A line dividing these
two phases could be present, showing a strong dependence on planet mass.
Although a larger sample will be required to establish a well-defined erosion
line, the distribution found is very suggestive. Conclusions: The distribution
of planetary mass with X-ray flux is consistent with a scenario in which planet
atmospheres have suffered the effects of erosion by coronal X-ray and EUV
emission. The erosion line is an observational constraint to models of
atmospheric erosion.Comment: A&A 511, L8 (2010). 4 pages, 3 figures, 1 online table (included).
Language edited; corrected a wrong unit conversion (g/s -> M_J/Gyr);
corrected values in column 12 of Table 1 (slightly underestimated in first
version), and Figure 2 updated accordingl
Hemorrhagic uterine necrosis after surgical vessel ligation and B-Lynch suture in persistent post-cesarean uterine atony: case report and review of literature
Uterine necrosis is a rare life-threatening condition reported in few case reports and series, associated with uterine artery embolization for uterine fibroids or postpartum hemorrhage. We report a hemorrhagic uterine necrosis in a nulliparous 35 years-old woman underwent cesarean section at 40+1 weeks of gestation for obstructed labor, presenting post-partum persisting bleeding and uterine atony and congestion. Bleeding stopped only after placement of two set of compressive sutures, curettage of uterine cavity and placement of Bakri Balloon but the uterine body never contracted and become congested. Notwithstanding an effective antibiotic therapy, the patient developed an intermittent fever and signs of severe anemia. Clinical and radiological diagnosis with CT and MRI scan were compatible with uterine necrosis characterized by hemorrhagic infarction of the uterine wall and decomposition of its muscular tissue. Hysterectomy was discussed with patient and performed on day 32 after C-section. Uterine apoplexy, a rare life-threatening disease, was detected with CT by lack of uterine contrast enhancement and a gas-filled uterine cavity and necrosis was confirmed with MRI by showing fluid degeneration of the myometrium. Failure to recognize a necrotic uterus on imaging can cause delayed hysterectomy, which is mandatory and potentially life-saving
Foliar lead uptake by lettuce exposed to atmospheric fallouts
Metal uptake by plants occurs by soil−root transfer but also by direct transfer of contaminants from the atmosphere to the shoots. This second pathway may be particularly important in kitchen gardens near industrial plants. The mechanisms of foliar uptake of lead by lettuce (Lactuca sativa) exposed to the atmospheric fallouts of a lead-recycling plant were studied. After 43 days of exposure, the thoroughly washed leaves contained 335 ± 50 mg Pb kg−1 (dry weight). Micro-X-ray fluorescence mappings evidenced Pb-rich spots of a few hundreds of micrometers in diameter located in necrotic zones. These spots were more abundant at the base of the central nervure. Environmental scanning electron microscopy coupled with energy dispersive X-ray microanalysis showed that smaller particles (a few micrometers in diameter) were also present in other regions of the leaves, often located beneath the leaf surface. In addition, submicrometric particles were observed inside stomatal openings. Raman microspectrometry analyses of the leaves identified smelter-originated Pb minerals but also secondary phases likely resulting from the weathering of original particles. On the basis of these observations, several pathways for foliar lead uptake are discussed. A better understanding of these mechanisms may be of interest for risk assessment of population exposure to atmospheric metal contamination
Performance of the TOTEM Detectors at the LHC
The TOTEM Experiment is designed to measure the total proton-proton
cross-section with the luminosity-independent method and to study elastic and
diffractive pp scattering at the LHC. To achieve optimum forward coverage for
charged particles emitted by the pp collisions in the interaction point IP5,
two tracking telescopes, T1 and T2, are installed on each side of the IP in the
pseudorapidity region 3.1 < = |eta | < = 6.5, and special movable beam-pipe
insertions - called Roman Pots (RP) - are placed at distances of +- 147 m and
+- 220 m from IP5. This article describes in detail the working of the TOTEM
detector to produce physics results in the first three years of operation and
data taking at the LHC.Comment: 40 pages, 31 figures, submitted to Int. J. Mod. Phys.
Cosmic-ray propagation in molecular clouds
Cosmic-rays constitute the main ionising and heating agent in dense,
starless, molecular cloud cores. We reexamine the physical quantities necessary
to determine the cosmic-ray ionisation rate (especially the cosmic ray spectrum
at E < 1 GeV and the ionisation cross sections), and calculate the ionisation
rate as a function of the column density of molecular hydrogen. Available data
support the existence of a low-energy component (below about 100 MeV) of
cosmic-ray electrons or protons responsible for the ionisation of diffuse and
dense clouds. We also compute the attenuation of the cosmic-ray flux rate in a
cloud core taking into account magnetic focusing and magnetic mirroring,
following the propagation of cosmic rays along flux tubes enclosing different
amount of mass and mass-to-flux ratios. We find that mirroring always dominates
over focusing, implying a reduction of the cosmic-ray ionisation rate by a
factor of 3-4 depending on the position inside the core and the magnetisation
of the core.Comment: To appear in "Cosmic Rays in Star-Forming Environments", Proceedings
of the 2nd Session of the Sant Cugat Forum on Astrophysics. D. F. Torres and
O. Reimer (Editors), 2013, Springer, 25 pages, 11 figure
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