85 research outputs found
The pathophysiology of restricted repetitive behavior
Restricted, repetitive behaviors (RRBs) are heterogeneous ranging from stereotypic body movements to rituals to restricted interests. RRBs are most strongly associated with autism but occur in a number of other clinical disorders as well as in typical development. There does not seem to be a category of RRB that is unique or specific to autism and RRB does not seem to be robustly correlated with specific cognitive, sensory or motor abnormalities in autism. Despite its clinical significance, little is known about the pathophysiology of RRB. Both clinical and animal models studies link repetitive behaviors to genetic mutations and a number of specific genetic syndromes have RRBs as part of the clinical phenotype. Genetic risk factors may interact with experiential factors resulting in the extremes in repetitive behavior phenotypic expression that characterize autism. Few studies of individuals with autism have correlated MRI findings and RRBs and no attempt has been made to associate RRB and post-mortem tissue findings. Available clinical and animal models data indicate functional and structural alterations in cortical-basal ganglia circuitry in the expression of RRB, however. Our own studies point to reduced activity of the indirect basal ganglia pathway being associated with high levels of repetitive behavior in an animal model. These findings, if generalizable, suggest specific therapeutic targets. These, and perhaps other, perturbations to cortical basal ganglia circuitry are mediated by specific molecular mechanisms (e.g., altered gene expression) that result in long-term, experience-dependent neuroadaptations that initiate and maintain repetitive behavior. A great deal more research is needed to uncover such mechanisms. Work in areas such as substance abuse, OCD, Tourette syndrome, Parkinson’s disease, and dementias promise to provide findings critical for identifying neurobiological mechanisms relevant to RRB in autism. Moreover, basic research in areas such as birdsong, habit formation, and procedural learning may provide additional, much needed clues. Understanding the pathophysioloy of repetitive behavior will be critical to identifying novel therapeutic targets and strategies for individuals with autism
The changing governance of the NHS: reform in a post-Keynesian health service'
This article suggests that the central problems of examining governance change in the National Health Service (NHS) are located in the changing relations between the state and the professionals it relies upon for the delivery of health services on the one hand, and its positioning of the users of public services on the other. These relations are explored in depth in terms of the question as to whether market-based governance can be adequately implemented in the NHS, examining the implications of this analysis for welfare governance reform more generally
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Plasma flow switch experiments on the Pegasus facility
Plasma flow switch experiments conducted on Pegasus have shown that a conducting layer of plasma shunts the load slot preventing efficient switching of current to the load. This effect is seen computationally. The magnitude of the effect depends on the specific parameters of the switch plasma and current level. Computations have also shown that a plasma boundary layer trap'' would effectively remove enough plasma from the inner conductor of the power flow channel so that efficient switching would occur. This plasma trap has been successfully demonstrated when used with a static load. It has not yet been tested with an imploding load. 3 refs., 8 figs
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