Attraction Region of Planar Linear Systems with One Unstable Pole and Saturated Feedback

Abstract.: The bifurcation of the attraction region for planar systems with one stable and one unstable pole under a saturated linear state feedback is considered. The attraction region can have either an unbounded hyperbolic shape or be bounded by a limit cycle. An analytical condition, under which either of these boundary shapes occurs, is given with a formal proof. This condition is based on the relationship between the stable and unstable manifolds associated with secondary saddle equilibrium points, whose presence is caused by the saturation on the inpu

Au-Fe alloy solidification and solid-state transformations

In order to better understand the microstructure that forms during laser welding of an 18 carat gold and an austenitic stainless steel, solidification of the Au-Fe binary analog has been studied using thermal analysis and interrupted Bridgman experiments. For a hypoperitectic composition, the formation of the primary phase, its coarsening and the peculiar macrosegregation associated with the large density difference between the elements have been studied. Just after the peritectic phase forms around the primary dendrites, continuous and discontinuous precipitation has been shown to occur as a result of the immiscibility of the two face-centered cubic phases below the peritectic temperature. Finally, the solid-state transformations associated with the eutectoid have been characterized. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Family coordination in families who have a child with autism spectrum disorder

Little is known about the interactions of families where there is a child with autism spectrum disorder (ASD). The present study applies the Lausanne Trilogue Play (LTP) to explore both its applicability to this population as well as to assess resources and areas of deficit in these families. The sample consisted of 68 families with a child with ASD, and 43 families with a typically developing (TD) child. With respect to the global score for family coordination there were several negative correlations: the more severe the symptoms (based on the child’s ADOS score), the more family coordination was dysfunctional. This correlation was particularly high when parents had to play together with the child. In the parts in which only one of the parents played actively with the child, while the other was simply present, some families did achieve scores in the functional range, despite the child’s symptom severity. The outcomes are discussed in terms of their clinical implications both for assessment and for interventio