8,379 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
Density functional theory study of the nematic-isotropic transition in an hybrid cell
We have employed the Density Functional Theory formalism to investigate the
nematic-isotropic capillary transitions of a nematogen confined by walls that
favor antagonist orientations to the liquid crystal molecules (hybrid cell). We
analyse the behavior of the capillary transition as a function of the
fluid-substrate interactions and the pore width. In addition to the usual
capillary transition between isotropic-like to nematic-like states, we find
that this transition can be suppressed when one substrate is wet by the
isotropic phase and the other by the nematic phase. Under this condition the
system presents interface-like states which allow to continuously transform the
nematic-like phase to the isotropic-like phase without undergoing a phase
transition. Two different mechanisms for the disappearance of the capillary
transition are identified. When the director of the nematic-like state is
homogeneously planar-anchored with respect to the substrates, the capillary
transition ends up in a critical point. This scenario is analogous to the
observed in Ising models when confined in slit pores with opposing surface
fields which have critical wetting transitions. When the nematic-like state has
a linearly distorted director field, the capillary transition continuously
transforms in a transition between two nematic-like states.Comment: 31 pages, 10 figures, submitted to J. Chem. Phy
The effect of pressure on statics, dynamics and stability of multielectron bubbles
The effect of pressure and negative pressure on the modes of oscillation of a
multi-electron bubble in liquid helium is calculated. Already at low pressures
of the order of 10-100 mbar, these effects are found to significantly modify
the frequencies of oscillation of the bubble. Stabilization of the bubble is
shown to occur in the presence of a small negative pressure, which expands the
bubble radius. Above a threshold negative pressure, the bubble is unstable.Comment: 4 pages, 2 figures, accepted for publication in Physical Review
Letter
Perturbative behaviour of a vortex in a trapped Bose-Einstein condensate
We derive a set of equations that describe the shape and behaviour of a
single perturbed vortex line in a Bose-Einstein condensate. Through the use of
a matched asymptotic expansion and a unique coordinate transform a relation for
a vortex's velocity, anywhere along the line, is found in terms of the
trapping, rotation, and distortion of the line at that location. This relation
is then used to find a set of differential equations that give the line's
specific shape and motion. This work corrects a previous similar derivation by
Anatoly A. Svidzinsky and Alexander L. Fetter [Phys. Rev. A \textbf{62}, 063617
(2000)], and enables a comparison with recent numerical results.Comment: 12 pages with 3 figure
Investigation of Conditions for Spontaneous Ignition and Combustion Efficiency of Pentaborane in a Small-scale Combustor
Properties of compact 250 μm emission and H II regions in M 33 (HERM33ES)
Aims. Within the framework of the HERM33ES key program, using the high resolution and sensitivity of the Herschel photometric
data, we study the compact emission in the Local Group spiral galaxy M33 to investigate the nature of the compact SPIRE emission
sources. We extracted a catalogue of sources at 250 μm in order to investigate the nature of this compact emission. Taking advantage
of the unprecedented Herschel resolution at these wavelengths, we also focus on a more precise study of some striking Hα shells in
the northern part of the galaxy.
Methods. We present a catalogue of 159 compact emission sources in M33 identified by SExtractor in the 250 μm SPIRE band that
is the one that provides the best spatial resolution. We also measured fluxes at 24 μm and Hα for those 159 extracted sources. The
morphological study of the shells also benefits from a multiwavelength approach including Hα, far-ultraviolet from GALEX, and
infrared from both Spitzer IRAC 8 μm and MIPS 24 μm in order to make comparisons.
Results. For the 159 compact sources selected at 250 μm, we find a very strong Pearson correlation coefficient with the MIPS 24 μm
emission (r_(24) = 0.94) and a rather strong correlation with the Hα emission, although with more scatter (r_(Hα) = 0.83). The morphological
study of the Hα shells shows a displacement between far-ultraviolet, Hα, and the SPIRE bands. The cool dust emission from
SPIRE clearly delineates the Hα shell structures.
Conclusions. The very strong link between the 250 μm compact emission and the 24 μm and Hα emissions, by recovering the star formation
rate from standard recipes for H II regions, allows us to provide star formation rate calibrations based on the 250 μm compact
emission alone. The different locations of the Hα and far-ultraviolet emissions with respect to the SPIRE cool dust emission leads to
a dynamical age of a few Myr for the Hα shells and the associated cool dust
Properties of compact 250 \mu m emission and HII regions in M33 (HERM33ES)
Within the framework of the HERM33ES Key Project, using the high resolution
and sensitivity of the Herschel photometric data, we study the compact emission
in the Local Group spiral galaxy M33 to investigate the nature of the compact
SPIRE emission sources. We extracted a catalogue of sources at 250um in order
to investigate the nature of this compact emission. Taking advantage of the
unprecedented Herschel resolution at these wavelengths, we also focus on a more
precise study of some striking Halpha shells in the northern part of the
galaxy. We present a catalogue of 159 compact emission sources in M33
identified by SExtractor in the 250um SPIRE band that is the one that provides
the best spatial resolution. We also measured fluxes at 24um and Halpha for
those 159 extracted sources. The morphological study of the shells also
benefits from a multiwavelength approach including Halpha, far-UV from GALEX,
and infrared from both Spitzer IRAC 8um and MIPS 24um in order to make
comparisons. For the 159 compact sources selected at 250um, we find a very
strong Pearson correlation coefficient with the MIPS 24um emission (r24 = 0.94)
and a rather strong correlation with the Halpha emission, although with more
scatter (rHa = 0.83). The morphological study of the Halpha shells shows a
displacement between far-ultraviolet, Halpha, and the SPIRE bands. The cool
dust emission from SPIRE clearly delineates the Halpha shell structures. The
very strong link between the 250um compact emission and the 24um and Halpha
emissions, by recovering the star formation rate from standard recipes for HII
regions, allows us to provide star formation rate calibrations based on the
250um compact emission alone. The different locations of the Halpha and
far-ultraviolet emissions with respect to the SPIRE cool dust emission leads to
a dynamical age of a few Myr for the Halpha shells and the associated cool
dust.Comment: 4 pages, 3 figures, Accpeted for publication in the A&A Herschel
Special Issu
Behaviour of piles driven in chalk
Driving resistance is difficult to predict in chalk strata, with both pile free-fall self-weight ‘runs’ and refusals being reported. Axial capacity is also highly uncertain after driving. This paper reviews recent research that has explored these topics. Programmes of onshore tests and novel, high-value offshore, experiments involving static, dynamic and cyclic loading are described. The key findings form the basis of the Chalk ICP-18 approach for estimating the driving resistance and axial capacity of piles driven in low-to medium-density chalk. The new approach is presented and the highly significant impact of set-up after driving is emphasised. It is shown that Chalk ICP-18 overcomes the main limitations of the industry’s current design guidelines by addressing the underlying physical mechanisms. While further tests are required to enlarge the available test database, the new approach is able to provide better predictions for tests available from suitably characterised sites. A new Joint Industry Project is outlined that extends the research to cover further axial, lateral, static and cyclic loading cases
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