132 research outputs found

    Anomaly Detection and Removal Using Non-Stationary Gaussian Processes

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    This paper proposes a novel Gaussian process approach to fault removal in time-series data. Fault removal does not delete the faulty signal data but, instead, massages the fault from the data. We assume that only one fault occurs at any one time and model the signal by two separate non-parametric Gaussian process models for both the physical phenomenon and the fault. In order to facilitate fault removal we introduce the Markov Region Link kernel for handling non-stationary Gaussian processes. This kernel is piece-wise stationary but guarantees that functions generated by it and their derivatives (when required) are everywhere continuous. We apply this kernel to the removal of drift and bias errors in faulty sensor data and also to the recovery of EOG artifact corrupted EEG signals.Comment: 9 pages, 14 figure

    Case report: Treatment of constrictive epicarditis using the waffle procedure in a dog that had previously undergone a subtotal pericardiectomy

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    A 10 year-old female spayed German Short-haired Pointer dog weighing 26.8 kg (59 lb) presented with a 2 week history of recurrent ascites. The dog had a 4 year history of idiopathic pericardial effusion causing sporadic episodes of cardiac tamponade and secondary ascites. A subtotal pericardiectomy was performed 3 months prior to presentation. The patient had done well for 2 months following this procedure, at which point the large-volume modified transudate ascites recurred, necessitating abdominocentesis every 10 days. Thoracic and abdominal computed tomography (CT) revealed no abdominal or vascular cause of ascites. Transthoracic echocardiography performed under general anesthesia showed constrictive epicarditis (visceral pericarditis) resulting in diastolic dysfunction and right-sided congestive heart failure. A sternotomy was performed for a pericardial waffle procedure or crosshatch pericardiotomy—scoring of crosshatched incisions into the thickened epicardium. Echocardiographic findings postoperatively were consistent with resolved constrictive epicarditis. At 8 months postoperatively, the dog was clinically normal and had only required one abdominocentesis one month after the waffle procedure. This case report describes the successful treatment of a dog with constrictive epicarditis using a novel surgical technique (waffle procedure) that has not yet been described in veterinary medicine

    Electoral management and the organisational determinants of electoral integrity

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    Achieving the ideals of electoral democracy depends on well-run elections. Persistent problems of electoral integrity in transitional and established democracies have prompted a burgeoning literature seeking to explain the determinants of electoral integrity around the world. However, the study of the organisations responsible for managing the electoral process has been limited to isolated national case studies. This article opens up an interdisciplinary and international research agenda on the global study of the organisational determinants of electoral integrity. It defines the concept of electoral management and provides a framework to understand how electoral management body (EMB) institutional design, EMB performance and electoral integrity are related. Findings from new data derived from cross-national surveys of EMBs are described, providing new insights into how elections are managed worldwide

    Identifying key drivers of the impact of an HIV cure intervention in sub-Saharan Africa

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    BACKGROUND:  The properties required of an intervention that results in eradication or control of HIV in absence of antiretroviral therapy (ART-free viral suppression) to make it cost-effective in low income settings are unknown. METHODS:  We used a model of HIV and ART to investigate the effect of introducing an ART-free viral suppression intervention in 2022 in an example country of Zimbabwe. We assumed that the intervention (cost: 500)wouldbeaccessiblefor90500) would be accessible for 90% of the population, be given to those on effective ART, have sufficient efficacy to allow ART interruption in 95%, with a rate of viral rebound 5% per year in the first three months, and a 50% decline in rate with each successive year. RESULTS:  An ART-free viral suppression intervention with these properties would result in over 0.53 million disability-adjusted-life-years averted over 2022-2042, with a reduction in HIV programme costs of 300 million (8.7% saving). An intervention of this efficacy costing anything up to $1400 is likely to be cost-effective in this setting. CONCLUSION:  Interventions aimed at curing HIV have the potential to improve overall disease burden and to reduce costs. Given the effectiveness and cost of ART, such interventions would have to be inexpensive and highly effective

    Tracheostomy in children is associated with neutrophilic airway inflammation

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    Background Tracheostomies in children are associated with significant morbidity, poor quality of life, excess healthcare costs and excess mortality. The underlying mechanisms facilitating adverse respiratory outcomes in tracheostomised children are poorly understood. We aimed to characterise airway host defence in tracheostomised children using serial molecular analyses. Methods Tracheal aspirates, tracheal cytology brushings and nasal swabs were prospectively collected from children with a tracheostomy and controls. Transcriptomic, proteomic and metabolomic methods were applied to characterise the impact of tracheostomy on host immune response and the airway microbiome. Results Children followed up serially from the time of tracheostomy up to 3 months postprocedure (n=9) were studied. A further cohort of children with a long-term tracheostomy were also enrolled (n=24). Controls (n=13) comprised children without a tracheostomy undergoing bronchoscopy. Long-term tracheostomy was associated with airway neutrophilic inflammation, superoxide production and evidence of proteolysis when compared with controls. Reduced airway microbial diversity was established pre-tracheostomy and sustained thereafter. Conclusions Long-term childhood tracheostomy is associated with a inflammatory tracheal phenotype characterised by neutrophilic inflammation and the ongoing presence of potential respiratory pathogens. These findings suggest neutrophil recruitment and activation as potential exploratory targets in seeking to prevent recurrent airway complications in this vulnerable group of patients

    Inferring causal molecular networks: empirical assessment through a community-based effort.

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    It remains unclear whether causal, rather than merely correlational, relationships in molecular networks can be inferred in complex biological settings. Here we describe the HPN-DREAM network inference challenge, which focused on learning causal influences in signaling networks. We used phosphoprotein data from cancer cell lines as well as in silico data from a nonlinear dynamical model. Using the phosphoprotein data, we scored more than 2,000 networks submitted by challenge participants. The networks spanned 32 biological contexts and were scored in terms of causal validity with respect to unseen interventional data. A number of approaches were effective, and incorporating known biology was generally advantageous. Additional sub-challenges considered time-course prediction and visualization. Our results suggest that learning causal relationships may be feasible in complex settings such as disease states. Furthermore, our scoring approach provides a practical way to empirically assess inferred molecular networks in a causal sense
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