10,254 research outputs found
Effectiveness of the ADEC as a level 2 screening test for young children with suspected autism spectrum disorders in a clinical setting
Background The Autism Detection in Early Childhood (ADEC) is a clinician-administered, Level 2 screening tool. A retrospective file audit was used to investigate its clinical effectiveness.
Method Toddlers referred to an Australian child development service between 2008 and 2010 (N?=?53, M age?=?32.2 months) were screened with the ADEC. Their medical records were reviewed in 2013 when their mean age was 74.5 months, and the original ADEC screening results were compared with later diagnostic outcomes.
Results The ADEC had good sensitivity (87.5%) and moderate specificity (62%). Three behaviours predicted autism spectrum disorders (ASDs): response to name, gaze switching, and gaze monitoring (p???.001).
Conclusions The ADEC shows promise as a screening tool that can discriminate between young children with ASDs and those who have specific communication disorders or developmental delays that persist into middle childhood but who do not meet the criteria for ASDs
Transparent Anomalous Dispersion and Superluminal Light Pulse Propagation at a Negative Group Velocity
Anomalous dispersion cannot occur in a transparent passive medium where
electromagnetic radiation is being absorbed at all frequencies, as pointed out
by Landau and Lifshitz. Here we show, both theoretically and experimentally,
that transparent linear anomalous dispersion can occur when a gain doublet is
present. Therefore, a superluminal light pulse propagation can be observed even
at a negative group velocity through a transparent medium with almost no pulse
distortion. Consequently, a {\it negative transit time} is experimentally
observed resulting in the peak of the incident light pulse to exit the medium
even before entering it. This counterintuitive effect is a direct result of the
{\it rephasing} process owing to the wave nature of light and is not at odds
with either causality or Einstein's theory of special relativity.Comment: 12 journal pages, 9 figure
Spectroscopy of drums and quantum billiards: perturbative and non-perturbative results
We develop powerful numerical and analytical techniques for the solution of
the Helmholtz equation on general domains. We prove two theorems: the first
theorem provides an exact formula for the ground state of an arbirtrary
membrane, while the second theorem generalizes this result to any excited state
of the membrane. We also develop a systematic perturbative scheme which can be
used to study the small deformations of a membrane of circular or square
shapes. We discuss several applications, obtaining numerical and analytical
results.Comment: 29 pages, 12 figures, 7 tabl
Cavitation and bubble collapse in hot asymmetric nuclear matter
The dynamics of embryonic bubbles in overheated, viscous and non-Markovian
nuclear matter is studied. It is shown that the memory and the Fermi surface
distortions significantly affect the hinderance of bubble collapse and
determine a characteristic oscillations of the bubble radius. These
oscillations occur due to the additional elastic force induced by the memory
integral.Comment: Revtex file (10 pages) and 3 figure
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