11,768 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

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    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

    Damping of metallic wool with embedded rigid body motion amplifiers

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    The use of entangled metallic wires as vibrational dampers and shock isolators is of interest in a variety of applications. By taking advantage of the frictional contact between the contiguous wires, it has been shown that significant amounts of energy dissipation can be achieved. The amount of energy dissipation is highly dependent on many factors with one in particular being the excitation amplitude. When the excitation amplitude is low, a combination of the number of contact points, in which have relative motion, and the contact pressure are lessened often leading to a sacrifice in energy dissipation. In this paper, spherical metallic rigid bodies are embedded within metallic wool. These rigid bodies act as motion amplifiers in which, locally within the metallic wool, amplify the excitation amplitude leading to an increase in vibrational damping. Presented are experimental modal results from various metallic wool/embedded rigid body arrangements within a prismatic hollow aluminium tube. It is found that the incorporation of the embedded rigid bodies into the steel wool significantly improves the damping within the system. It is demonstrated that an increase in damping by 2328% has been achieved at only a 3.8% penalty in mass. It is found that the level of damping from the embedded rigid bodies depends not only on the excitation amplitude but their quantity and the accompanying steel wool configuration. A finite element procedure coupled with an analytical model is proposed which accounts for the strain energy produced within the steel wool to estimate the damping effect that this filler material has on the behaviour of the overall structure. The model treats the metallic wool/rigid sphere combination as a homogeneous equivalent solid with amplitude dependent damping properties, thereby reducing the complexities of the physics-based model while still providing an estimate of the vibrational damping while in the frequency domain

    Linear oscillations of a compressible hemispherical bubble on a solid substrate

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    The linear natural and forced oscillations of a hemispherical bubble on a solid substrate are under theoretical consideration. The contact line dynamics is taken into account with the Hocking condition, which eventually leads to interaction of the shape and volume oscillations. Resonant phenomena, mostly pronounced for the bubble with the fixed contact line or with the fixed contact angle, are found out. The limiting case of weakly compressible bubble is studied. The general criterion identifying whether the compressibility of a bubble can be neglected is obtained.Comment: new slightly extended version with some minor changes, added journal reference and DOI information; 12 pages, 8 figures, published in Physics of Fluid

    Mathematical and numerical evaluation of the damping behaviour for a multi-strand bar

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    Multi-strand systems include, but are not limited to, electrical wire conductors, structural cables, and some composite reinforcements. These systems (apart from composite reinforcements) are generally metallic for a variety of reasons. One often overlooked advantage is that dry friction between metal contacts can provide damping over significantly wider temperature ranges than is typical for common damping materials such as viscoelastic polymers. This paper, proposes a mathematical model that describes the hysteretic vibrational behaviour of a frictionally constrained multi-strand bar constructed from strands that have a circular cross-section. The mathematical model analytically predicts the frictional system stiffness under simply supported boundary conditions. The assembled strands are numerically simulated using finite elements and hysteresis behaviour is compared to that obtained from the mathematical model. This shows that the mathematical model is capable of predicting the stiffness and the force-displacement hysteresis response of the system for a variety of conditions

    Retrograde transport pathways utilised by viruses and protein toxins

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    A model has been presented for retrograde transport of certain toxins and viruses from the cell surface to the ER that suggests an obligatory interaction with a glycolipid receptor at the cell surface. Here we review studies on the ER trafficking cholera toxin, Shiga and Shiga-like toxins, Pseudomonas exotoxin A and ricin, and compare the retrograde routes followed by these protein toxins to those of the ER trafficking SV40 and polyoma viruses. We conclude that there is in fact no obligatory requirement for a glycolipid receptor, nor even with a protein receptor in a lipid-rich environment. Emerging data suggests instead that there is no common pathway utilised for retrograde transport by all of these pathogens, the choice of route being determined by the particular receptor utilised

    Orbital assembly and maintenance study

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    The requirements, conceptual design, tradeoffs, procedures, and techniques for orbital assembly of the support structure of the microwave power transmission system and the radio astronomy telescope are described. Thermal and stress analyses, packaging, alignment, and subsystems requirements are included along with manned vs. automated and transportation tradeoffs. Technical and operational concepts for the manned and automated maintenance of satellites were investigated and further developed results are presented
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