727 research outputs found

    Kondo effect in a one dimensional d-wave superconductor

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    We derive a solvable resonant-level type model, to describe an impurity spin coupled to zero-energy bound states localized at the edge of a one dimensional d-wave superconductor. This results in a two-channel Kondo effect with a quite unusual low-temperature thermodynamics. For instance, the local impurity susceptibility yields a finite maximum at zero temperature (but no logarithmic-divergence) due to the splitting of the impurity in two Majorana fermions. Moreover, we make comparisons with the Kondo effect occurring in a two dimensional d-wave superconductor.Comment: 9 pages, final version; To be published in Europhysics Letter

    Brain Biomarkers and Pre-Injury Cognition are Associated with Long-Term Cognitive Outcome in Children with Traumatic Brain Injury

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    BACKGROUND: Children with traumatic brain injury (TBI) are frequently at risk of long-term impairments of attention and executive functioning but these problems are difficult to predict. Although deficits have been reported to vary with injury severity, age at injury and sex, prognostication of outcome remains imperfect at a patient-specific level. The objective of this proof of principle study was to evaluate a variety of patient variables, along with six brain-specific and inflammatory serum protein biomarkers, as predictors of long-term cognitive outcome following paediatric TBI. METHOD: Outcome was assessed in 23 patients via parent-rated questionnaires related to attention deficit hyperactivity disorder (ADHD) and executive functioning, using the Conners 3rd Edition Rating Scales (Conners-3) and Behaviour Rating Inventory of Executive Function (BRIEF) at a mean time since injury of 3.1 years. Partial least squares (PLS) analyses were performed to identify factors measured at the time of injury that were most closely associated with outcome on (1) the Conners-3 and (2) the Behavioural Regulation Index (BRI) and (3) Metacognition Index (MI) of the BRIEF. RESULTS: Higher levels of neuron specific enolase (NSE) and lower levels of soluble neuron cell adhesion molecule (sNCAM) were associated with higher scores on the inattention, hyperactivity/impulsivity and executive functioning scales of the Conners-3, as well as working memory and initiate scales of the MI from the BRIEF. Higher levels of NSE only were associated with higher scores on the inhibit scale of the BRI. CONCLUSIONS: NSE and sNCAM show promise as reliable, early predictors of long-term attention-related and executive functioning problems following paediatric TBI

    A Weighted Prognostic Covariate Adjustment Method for Efficient and Powerful Treatment Effect Inferences in Randomized Controlled Trials

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    A crucial task for a randomized controlled trial (RCT) is to specify a statistical method that can yield an efficient estimator and powerful test for the treatment effect. A novel and effective strategy to obtain efficient and powerful treatment effect inferences is to incorporate predictions from generative artificial intelligence (AI) algorithms into covariate adjustment for the regression analysis of a RCT. Training a generative AI algorithm on historical control data enables one to construct a digital twin generator (DTG) for RCT participants, which utilizes a participant's baseline covariates to generate a probability distribution for their potential control outcome. Summaries of the probability distribution from the DTG are highly predictive of the trial outcome, and adjusting for these features via regression can thus improve the quality of treatment effect inferences, while satisfying regulatory guidelines on statistical analyses, for a RCT. However, a critical assumption in this strategy is homoskedasticity, or constant variance of the outcome conditional on the covariates. In the case of heteroskedasticity, existing covariate adjustment methods yield inefficient estimators and underpowered tests. We propose to address heteroskedasticity via a weighted prognostic covariate adjustment methodology (Weighted PROCOVA) that adjusts for both the mean and variance of the regression model using information obtained from the DTG. We prove that our method yields unbiased treatment effect estimators, and demonstrate via comprehensive simulation studies and case studies from Alzheimer's disease that it can reduce the variance of the treatment effect estimator, maintain the Type I error rate, and increase the power of the test for the treatment effect from 80% to 85%~90% when the variances from the DTG can explain 5%~10% of the variation in the RCT participants' outcomes.Comment: 49 pages, 6 figures, 12 table

    The practice of glycaemic control in intensive care units: A multicentre survey of nursing and medical professionals.

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    AIMS AND OBJECTIVES: To determine the views of nurses and physicians working in intensive care units (ICU) about the aims of glycaemic control and use of their protocols. BACKGROUND: Evidence about the optimal aims and methods for glycaemic control in ICU is controversial, and current local protocols guiding practice differ between ICUs, both nationally and internationally. The views of professionals on glycaemic control can influence their practice. DESIGN: Cross-sectional, multicentre, survey-based study. METHODS: An online short survey was sent to all physicians and nurses of seven ICUs, including questions on effective glycaemic control, treatment of hypoglycaemia and deviations from protocols' instructions. STROBE reporting guidelines were followed. RESULTS: Over half of the 40 respondents opined that a patient spending <75% admission time within the target glycaemic levels constituted poor glycaemic control. Professionals with more than 5 years of experience were more likely to rate a patient spending 50%-74% admission time within target glycaemic levels as poor than less experienced colleagues. Physicians were more likely to rate a patient spending <50% admission time within target as poor than nurses. There was general agreement on how professionals would rate most deviations from their protocols. Nurses were more likely to rate insulin infusions restarted late and incorrect dosage of rescue glucose as major deviations than physicians. Most professionals agreed on when they would treat hypoglycaemia. CONCLUSIONS: When surveyed on various aspects of glycaemic control, ICU nurses and physicians often agreed, although there were certain areas of disagreement, in which their profession and level of experience seemed to play a role. RELEVANCE TO CLINICAL PRACTICE: Differing views on glycaemic control amongst professionals may affect their practice and, thus, could lead to health inequalities. Clinical leads and the multidisciplinary ICU team should assess and, if necessary, address these differing opinions.Nottingham University Hospitals (NUH) Charity and the NUH Department of Research and Innovation University of Nottingham School of Health Sciences director of research small grant

    Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in acute lung injury to reduce pulmonary dysfunction (HARP-2) trial : study protocol for a randomized controlled trial

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    Acute lung injury (ALI) is a common devastating clinical syndrome characterized by life-threatening respiratory failure requiring mechanical ventilation and multiple organ failure. There are in vitro, animal studies and pre-clinical data suggesting that statins may be beneficial in ALI. The Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in Acute lung injury to Reduce Pulmonary dysfunction (HARP-2) trial is a multicenter, prospective, randomized, allocation concealed, double-blind, placebo-controlled clinical trial which aims to test the hypothesis that treatment with simvastatin will improve clinical outcomes in patients with ALI

    The National Competency Framework for Registered Nurses in Adult Critical Care: an overview

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    In the years following the abolition of the English National Board for Nursing, Midwifery and Health Visiting in 2002, concerns were raised within the Critical Care nursing community about a lack of consistency in post-registration education programmes. In response to this, the Critical Care Network National Nurse Leads (CC3N) formed a sub-group, the Critical Care Nurse Education Review Forum (CCNERF) to address these concerns. A review of UK course provision confirmed marked inconsistency in the length, content and associated academic award. The CCNERF commenced a two-phase project, first developing national standards for critical care nurse education such as length of course and academic credit level, followed by the development of a national competency framework. Following significant review and revision, version two of the National Competency Framework for Registered Nurses in Adult Critical Care was published by CC3N in 2015. This paper introduces the National Competency Framework and provides an overview of its background, development and implementation. It then considers the future direction of UK post-registration Critical Care nurse education

    Security that matters: critical infrastructure and objects of protection

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    Critical infrastructure protection is prominently concerned with objects that appear indispensable for the functioning of social and political life. However, the analysis of material objects in discussions of critical infrastructure protection has remained largely within the remit of managerial responses, which see matter as simply passive, a blank slate. In security studies, critical approaches have focused on social and cultural values, forms of life, technologies of risk or structures of neoliberal globalization. This article engages with the role of "things" or of materiality for theories of securitization. Drawing on the materialist feminism of Karen Barad, it shows how critical infrastructure in Europe neither is an empty receptacle of discourse nor has "essential" characteristics; rather, it emerges out of material-discursive practices. Understanding the securitization of critical infrastructure protection as a process of materialization allows for a reconceptualization of how security matters and its effects

    The Efficacy of the COMFORT Scale in Assessing Optimal Sedation in Critically Ill Children Requiring Mechanical Ventilation

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    Sedation is often necessary to optimize care for critically ill children requiring mechanical ventilation. If too light or too deep, however, sedation can cause significant adverse reactions, making it important to assess the degree of sedation and maintain its optimal level. We evaluated the efficacy of the COMFORT scale in assessing optimal sedation in critically ill children requiring mechanical ventilation. We compared 12 month data in 21 patients (intervention group), for whom we used the pediatric intensive care unit (PICU) sedation protocol of Asan Medical Center (Seoul, Korea) and the COMFORT scale to maintain optimal sedation, with the data in 20 patients (control group) assessed before using the sedation protocol and the COMPORT scale. Compared with the control group, the intervention group showed significant decreases in the total usage of sedatives and analgesics, the duration of mechanical ventilation (11.0 days vs. 12.5 days) and PICU stay (15.0 days vs. 19.5 days), and the development of withdrawal symptoms (1 case vs. 7 cases). The total duration of sedation (8.0 days vs. 11.5 days) also tended to decrease. These findings suggest that application of protocol-based sedation with the COMPORT scale may benefit children requiring mechanical ventilation
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