65 research outputs found

    Characteristic Evolution and Matching

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    I review the development of numerical evolution codes for general relativity based upon the characteristic initial value problem. Progress in characteristic evolution is traced from the early stage of 1D feasibility studies to 2D axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black hole spacetime. Cauchy codes have now been successful at simulating all aspects of the binary black hole problem inside an artificially constructed outer boundary. A prime application of characteristic evolution is to extend such simulations to null infinity where the waveform from the binary inspiral and merger can be unambiguously computed. This has now been accomplished by Cauchy-characteristic extraction, where data for the characteristic evolution is supplied by Cauchy data on an extraction worldtube inside the artificial outer boundary. The ultimate application of characteristic evolution is to eliminate the role of this outer boundary by constructing a global solution via Cauchy-characteristic matching. Progress in this direction is discussed.Comment: New version to appear in Living Reviews 2012. arXiv admin note: updated version of arXiv:gr-qc/050809

    Exercising 'soft closure' on lay health knowledge? Harnessing the declining power of the medical profession to improve online health information

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    This study aims to address the increasingly complex medical predicament of low quality online health information contributing to lay health knowledge and consequently to clinical outcomes. We situate the predicament within a social change paradigm of individualism, choice, diminishing medical power, and emergence of the legitimacy of lay health knowledge. We contend that the prominence of lay health knowledge has been facilitated by the internet, and is due to a surge in broadcasting of experiential knowledge coupled with increased access to and enactment of medical and non-medically sanctioned online information on health and illness. We draw on and further test the application of social closure theory to help conceive a potential solution to this enduring problem. We conduct a quality assessment of an indicative case study, Apicectomies, and test the application of our notion of soft closure on its findings, resulting in targeted, feasible and potentially beneficial solutions to increasing the medical quality of online health information. We further present the extant application of soft closure by Healthtalkonline.org, which collates a medically reliable set of experiential knowledge on a range of health issues. As such, we propose a constructive re-enactment of the traditional closure of the medical profession on medical knowledge

    Outcome of crisis intervention for borderline personality disorder and post traumatic stress disorder: a model for modification of the mechanism of disorder in complex post traumatic syndromes

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    <p>Abstract</p> <p>Background</p> <p>This study investigates the outcome of crisis intervention for chronic post traumatic disorders with a model based on the theory that such crises manifest trauma in the present. The sufferer's behavior is in response to the current perception of dependency and entrapment in a mistrusted relationship. The mechanism of disorder is the sufferer's activity, which aims to either prove or disprove the perception of entrapment, but, instead, elicits more semblances of it in a circular manner. Patients have reasons to keep such activity private from therapy and are barely aware of it as the source of their symptoms.</p> <p>Methods</p> <p>The hypothesis is that the experimental intervention will reduce symptoms broadly within 8 to 24 h from initiation of treatment, compared to treatment as usual. The experimental intervention sidesteps other symptoms to engage patients in testing the trustworthiness of the troubled relationship with closure, thus ending the circularity of their own ways. The study compares 32 experimental subjects with 26 controls at similar crisis stabilization units.</p> <p>Results</p> <p>The results of the Brief Psychiatric Rating Scale (BPRS) supported the hypothesis (both in total score and for four of five subscales), as did results with Client Observation, a pilot instrument designed specifically for the circular behavior targeted by the experimental intervention. Results were mostly non-significant from two instruments of patient self-observation, which provided retrospective pretreatment scores.</p> <p>Conclusions</p> <p>The discussion envisions further steps to ascertain that this broad reduction of symptoms ensues from the singular correction that distinguishes the experimental intervention.</p> <p>Trial registration</p> <p>Protocol Registration System NCT00269139. The PRS URL is <url>https://register.clinicaltrials.gov</url></p

    Characteristic Evolution and Matching

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    I review the development of numerical evolution codes for general relativity based upon the characteristic initial value problem. Progress is traced from the early stage of 1D feasibility studies to 2D axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black spacetime. A prime application of characteristic evolution is to compute waveforms via Cauchy-characteristic matching, which is also reviewed.Comment: Published version http://www.livingreviews.org/lrr-2005-1

    Exploring altered affective processing in obsessive-compulsive disorder symptom subtypes

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    To investigate the bias toward recognising facial expression of disgust in obsessive compulsive disorder as well as the effect of escitalopram

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    Please help populate SUNScholar with the full text of SU research output. Also - should you need this item urgently, please send us the details and we will try to get hold of the full text as quick possible. E-mail to [email protected]. Thank you.Journal Articles (subsidised)Geneeskunde en GesondheidswetenskappePsigiatri

    Pharmocotherapy for anxiety disorders in children and adolescents (Review)

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    Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]
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