3,234 research outputs found

    An observational audit of pain scores post-orthopaedic surgery at a level two state hospital in Cape Town

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    Objectives: The aim was to determine whether postoperative pain is satisfactorily controlled in patients undergoing orthopaedic surgery at a level two state hospital in Cape Town.Design: Two observational audits were performed 12 months apart as part of a full audit cycle.Setting and subjects: In view of perceived poor postoperative pain control, an audit was performed of acute postoperative pain scores, anaesthesia techniques, and patient satisfaction with pain control. Orthopaedic patients undergoing surgical procedures at a level two state hospital in Cape Town were enrolled in the two audits. Patient groups included both patientsadmitted to the hospital and day-cases.Outcome measures: Patients admitted to hospital following major surgery, rated their perceived pain over 48 hours, using a visual analogue scale (VAS). Day-case patients scored their pain in hospital, and were then contacted telephonically after 24 hours, and if required, after 48 hours. A VAS score . 4 was regarded as unacceptable. The interventions employed after the first audit were: pain rounds, staff education and training,  increased postoperative epidural time, patient-controlled analgesia pumps and indwelling femoral catheters following total knee replacement.Results: Data were analysed from 71 patients in each audit. Mean VAS scores were unacceptable 12 and 24 hours after major surgery (range 4 - 5.1 in audit 1). Following the introduction of the aforementioned  interventions, the mean pain scores were < 4 at every time point  measurement, and significantly lower than in audit 1 at most assessment times (p < 0.05). Patient satisfaction with pain control improved from 32.4% in audit 1 to 54.9% in audit 2.Conclusion: Acute postoperative pain is an important clinical problem in orthopaedic surgery. Following the demonstration of unacceptable  postoperative pain scores in the first audit, specific interventions were shown to significantly improve pain control in the follow-up audit

    A Theory of Cheap Control in Embodied Systems

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    We present a framework for designing cheap control architectures for embodied agents. Our derivation is guided by the classical problem of universal approximation, whereby we explore the possibility of exploiting the agent's embodiment for a new and more efficient universal approximation of behaviors generated by sensorimotor control. This embodied universal approximation is compared with the classical non-embodied universal approximation. To exemplify our approach, we present a detailed quantitative case study for policy models defined in terms of conditional restricted Boltzmann machines. In contrast to non-embodied universal approximation, which requires an exponential number of parameters, in the embodied setting we are able to generate all possible behaviors with a drastically smaller model, thus obtaining cheap universal approximation. We test and corroborate the theory experimentally with a six-legged walking machine. The experiments show that the sufficient controller complexity predicted by our theory is tight, which means that the theory has direct practical implications. Keywords: cheap design, embodiment, sensorimotor loop, universal approximation, conditional restricted Boltzmann machineComment: 27 pages, 10 figure

    Negotiating daughterhood and strangerhood: retrospective accounts of serial migration

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    Most considerations of daughtering and mothering take for granted that the subjectivities of mothers and daughters are negotiated in contexts of physical proximity throughout daughters’ childhoods. Yet many mothers and daughters spend periods separated from each other, sometimes across national borders. Globally, an increasing number of children experience life in transnational families. This paper examines the retrospective narratives of four women who were serial migrants as children (whose parents migrated before they did) . It focuses on their accounts of the reunion with their mothers and how these fit with the ways in which they construct their mother-daughter relationships. We take a psychosocial approach by using a psychoanalytically-informed reading of these narratives to acknowledge the complexities of the attachments produced in the context of migration and to attend to the multi-layered psychodynamics of the resulting relationships. The paper argues that serial migration positioned many of the daughters in a conflictual emotional landscape from which they had to negotiate ‘strangerhood’ in the context of sadness at leaving people to whom they were attached in order to join their mothers (or parents). As a result, many were resistant to being positioned as daughters, doing daughtering and being mothered in their new homes

    The Cosmic Infrared Background: Measurements and Implications

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    The cosmic infrared background records much of the radiant energy released by processes of structure formation that have occurred since the decoupling of matter and radiation following the Big Bang. In the past few years, data from the Cosmic Background Explorer mission provided the first measurements of this background, with additional constraints coming from studies of the attenuation of TeV gamma-rays. At the same time there has been rapid progress in resolving a significant fraction of this background with the deep galaxy counts at infrared wavelengths from the Infrared Space Observatory instruments and at submillimeter wavelengths from the Submillimeter Common User Bolometer Array instrument. This article reviews the measurements of the infrared background and sources contributing to it, and discusses the implications for past and present cosmic processes.Comment: 61 pages, incl. 9 figures, to be published in Annual Reviews of Astronomy and Astrophysics, 2001, Vol. 3

    Credit assignment to state-independent task representations and its relationship with model-based decision making

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    Model-free learning enables an agent to make better decisions based on prior experience while representing only minimal knowledge about an environment’s structure. It is generally assumed that model-free state representations are based on outcome-relevant features of the environment. Here, we challenge this assumption by providing evidence that a putative model-free system assigns credit to task representations that are irrelevant to an outcome. We examined data from 769 individuals performing a well-described 2-step reward decision task where stimulus identity but not spatial-motor aspects of the task predicted reward. We show that participants assigned value to spatial-motor representations despite it being outcome irrelevant. Strikingly, spatial-motor value associations affected behavior across all outcome-relevant features and stages of the task, consistent with credit assignment to low-level state-independent task representations. Individual difference analyses suggested that the impact of spatial-motor value formation was attenuated for individuals who showed greater deployment of goal-directed (model-based) strategies. Our findings highlight a need for a reconsideration of how model-free representations are formed and regulated according to the structure of the environment

    Immunoblot analysis of the seroreactivity to recombinant Borrelia burgdorferi sensu lato antigens, including VlsE, in the long-term course of treated patients with Erythema migrans

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    Objective: We evaluated whether immunoblotting is capable of substantiating the posttreatment clinical assessment of patients with erythema migrans ( EM), the hallmark of early Lyme borreliosis. Methods: In 50 patients, seroreactivity to different antigens of Borrelia burgdorferi sensu lato was analyzed by a recombinant immunoblot test (IB) in consecutive serum samples from a minimum follow-up period of 1 year. Antigens in the IgG test were decorin- binding protein A, internal fragment of p41 (p41i), outer surface protein C (OspC), p39, variable major protein-like sequence expressed (VlsE), p58 and p100; those in the IgM test were p41i, OspC and p39. Immune responses were correlated with clinical and treatment-related parameters. Results: Positive IB results were found in 50% before, in 57% directly after therapy and in 44% by the end of the follow-up for the IgG class, and in 36, 43 and 12% for the IgM class. In acute and convalescence phase sera, VlsE was most immunogenic on IgG testing 60 and 70%), and p41i (46 and 57%) and OspC (40 and 57%) for the IgM class. By the end of the follow-up, only the anti-p41i lgM response was significantly decreased to 24%. Conclusions: No correlation was found between IB results and treatment-related parameters. Thus, immunoblotting does not add to the clinical assessment of EM patients after treatment. Copyright (c) 2008 S. Karger AG, Basel

    Assessment of Safety and Efficacy of Safinamide as a Levodopa Adjunct in Patients With Parkinson Disease and Motor Fluctuations A Randomized Clinical Trial

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    IMPORTANCE: Although levodopa remains the most effective oral pharmacotherapy for Parkinson disease (PD), its use is often limited by wearing off effect and dyskinesias. Management of such complications continues to be a significant challenge. OBJECTIVE: To investigate the efficacy and safety of safinamide (an oral aminoamide derivative with dopaminergic and nondopaminergic actions) in levodopa-treated patients with motor fluctuations. DESIGN, SETTING, AND PARTICIPANTS: From March 5, 2009, through February 23, 2012, patients from academic PD care centers were randomized (1:1 ratio) to receive double-blind adjunctive safinamide or placebo for 24 weeks. All patients had idiopathic PD with “off” time (time when medication effect has worn off and parkinsonian features, including bradykinesia and rigidity, return) of greater than 1.5 hours per day (excluding morning akinesia). Their pharmacotherapy included oral levodopa plus benserazide or carbidopa in a regimen that had been stable for 4 weeks or longer. During screening, each patient’s regimen was optimized to minimize motor fluctuations. Study eligibility required that after 4 weeks of optimized treatment, the patients still have more than 1.5 hours per day of off time. Adverse events caused the premature study discontinuation of 12 individuals (4.4%) in the safinamide group and 10 individuals (3.6%) in the placebo group. INTERVENTIONS: Patients took safinamide or placebo as 1 tablet daily with breakfast. If no tolerability issues arose by day 14, the starting dose, 50 mg, was increased to 100 mg. MAIN OUTCOMES AND MEASURES: The prespecified primary outcome was each treatment group’s mean change from baseline to week 24 (or last “on” treatment value) in daily “on” time (relief of parkinsonian motor features) without troublesome dyskinesia, as assessed from diary data. RESULTS: At 119 centers, 549 patients were randomized (mean [SD] age, 61.9 [9.0] years; 334 male [60.8%] and 371 white [67.6%]): 274 to safinamide and 275 to placebo. Among them, 245 (89.4%) receiving safinamide and 241 (87.6%) receiving placebo completed the study. Mean (SD) change in daily on time without troublesome dyskinesia was +1.42 (2.80) hours for safinamide, from a baseline of 9.30 (2.41) hours, vs +0.57 (2.47) hours for placebo, from a baseline of 9.06 (2.50) hours (least-squares mean difference, 0.96 hour; 95% CI, 0.56-1.37 hours; P < .001, analysis of covariance). The most frequently reported adverse event was dyskinesia (in 40 [14.6%] vs 15 [5.5%] and as a severe event in 5 [1.8%] vs 1 [0.4%]). CONCLUSIONS AND RELEVANCE: The outcomes of this trial support safinamide as an effective adjunct to levodopa in patients with PD and motor fluctuations to improve on time without troublesome dyskinesia and reduce wearing off
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