1,396 research outputs found

    Decision making with decision event graphs

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    We introduce a new modelling representation, the Decision Event Graph (DEG), for asymmetric multistage decision problems. The DEG explicitly encodes conditional independences and has additional significant advantages over other representations of asymmetric decision problems. The colouring of edges makes it possible to identify conditional independences on decision trees, and these coloured trees serve as a basis for the construction of the DEG. We provide an efficient backward-induction algorithm for finding optimal decision rules on DEGs, and work through an example showing the efficacy of these graphs. Simplifications of the topology of a DEG admit analogues to the sufficiency principle and barren node deletion steps used with influence diagrams

    Letter from R[euben] G. Thwaites to John Muir, 1913 Sep 15.

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    REUBEN G. THWAITESSuperintendent September 15, 1913.Mr. John Muir,Martinez, California.My clear Mr. Muir: Thank you most cordially for your welcome gift to this library of your portrait and your autobiography. We are delighted to get both of them, and the gift is very greatly enhanced by the addition of your autograph. I assure you that we shall treasure them highly as coming from a son of Wisconsin, whom we all delight to honor.I am, Sir, with high esteems Yours very truly,RGT-EEL SuperintendentROT-EELI am, sir, with high estee

    Step away from the zero lower bound: Small open economies in a world of secular stagnation

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    We study how small open economies can escape from deflation and unemployment in a situation where the world economy is permanently depressed. Building on the framework of Eggertsson et al. (2016), we show that the transition to full employment and at-target inflation requires real and nominal depreciation of the exchange rate. However, because of adverse income and valuation effects from real depreciation, the escape has a beggar- thy-self effect, that may end up lowering welfare while eliminating underemployment. We show that as long as the economy remains financially open, domestic asset supply policies or reducing the effective lower bound on policy rates may be ineffective or even counter- productive. However, closing domestic capital markets does not necessarily enhance the monetary authorities’ ability to rescue the economy from stagnation

    The management of tetanus in adults in an intensive care unit in Southern Vietnam

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    Background: Tetanus remains common in many low- and middle-income countries (LMICs) yet the evidence base guiding management of this disease is extremely limited, particularly with respect to contemporary management options. Sharing knowledge about practice may facilitate improvement in outcomes elsewhere. Methods: We describe clinical interventions and outcomes of 180 adult patients ≥16 years-old with tetanus enrolled in prospective observational studies at a specialist infectious diseases hospital in Southern Vietnam. Patients were treated according to a holistic management protocol encompassing wound-care, antitoxin, antibiotics, symptom control, airway management, nutrition and de-escalation criteria. Results: Mortality rate in our cohort was 2.8%, with 90 (50%) patients requiring mechanical ventilation for a median 16 [IQR 12-24] days. Median [IQR] duration of ICU stay was 15 [8-23] days. Autonomic nervous system dysfunction occurred in 45 (25%) patients. Hospital acquired infections occurred in 77 (43%) of patients. Conclusion: We report favourable outcomes for patients with tetanus in a single centre LMIC ICU, treated according to a holistic protocol. Nevertheless, many patients required prolonged intensive care support and hospital acquired infections were common

    Reliability and Diagnostic Performance of CT Imaging Criteria in the Diagnosis of Tuberculous Meningitis

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    The original publication is available at http:// www.plosone.orgPublication of this article was funded by the Stellenbosch University Open Access Fund.Introduction: Abnormalities on CT imaging may contribute to the diagnosis of tuberculous meningitis (TBM). Recently, an expert consensus case definition (CCD) and set of imaging criteria for diagnosing basal meningeal enhancement (BME) have been proposed. This study aimed to evaluate the sensitivity, specificity and reliability of these in a prospective cohort of adult meningitis patients. Methods: Initial diagnoses were based on the CCD, classifying patients into: ‘Definite TBM’ (microbiological confirmation), ‘Probable TBM’ (diagnostic score $10), ‘Possible TBM’ (diagnostic score 6–9), ‘Not TBM’ (confirmation of an alternative diagnosis) or ‘Uncertain’ (diagnostic score of ,6). CT images were evaluated independently on two occasions by four experienced reviewers. Intra-rater and inter-rater agreement were calculated using the kappa statistic. Sensitivities and specificities were calculated using both ‘Definite TBM’ and either ‘Definite TBM’ or ‘Probable TBM’ as gold standards. Results: CT scan criteria for BME had good intra-rater agreement (k range 0.35–0.78) and fair to moderate inter-rater agreement (k range 0.20–0.52). Intra- and inter-rater agreement on the CCD components were good to fair (k = ranges 0.47–0.81 and 0.21–0.63). Using ‘Definite TBM’ as a gold standard, the criteria for BME were very specific (61.5%–100%), but insensitive (5.9%–29.4%). Similarly, the imaging components of the CCD were highly specific (69.2–100%) but lacked sensitivity (0–56.7%). Similar values were found when using ‘Definite TBM’ or ‘Probable TBM’ as a gold standard. Discussion: The fair to moderate inter-rater agreement and poor sensitivities of the criteria for BME suggest that little reliance should be placed in these features in isolation. While the presence of the CCD criteria of acute infarction or tuberculoma(s) appears useful as rule-in criteria, their absence is of little help in excluding TBM. The CCD and criteria for BME, as well as any new criteria, need to be standardized and validated in prospective cohort studies.Funding: KB received funding from the Discovery Foundation (Academic Fellowship Award; http://www.discovery.co.za/portal/loggedout-individual/discoverycommunity- about), College of Neurology of South Africa (K.M. Browse Award; http://www.collegemedsa.ac.za/Default.aspx ) and the University of Stellenbosch. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Publisher's versio

    Modelling with non-stratified chain event graphs

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    © 2019, Springer Nature Switzerland AG. Chain Event Graphs (CEGs) are recent probabilistic graphical modelling tools that have proved successful in modelling scenarios with context-specific independencies. Although the theory underlying CEGs supports appropriate representation of structural zeroes, the literature so far does not provide an adaptation of the vanilla CEG methods for a real-world application presenting structural zeroes also known as the non-stratified CEG class. To illustrate these methods, we present a non-stratified CEG representing a public health intervention designed to reduce the risk and rate of falling in the elderly. We then compare the CEG model to the more conventional Bayesian Network model when applied to this setting

    Excavations and the afterlife of a professional football stadium, Peel Park, Accrington, Lancashire: towards an archaeology of football

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    Association football is now a multi-billion dollar global industry whose emergence spans the post-medieval to the modern world. With its professional roots in late 19th-century industrial Lancashire, stadiums built for the professionalization of football first appear in frequency in the North of England. While many historians of sport focus on consumerism and ‘topophilia’ (attachment to place) regarding these local football grounds, archaeological research that has been conducted on the spectator experience suggests status differentiation within them. Our excavations at Peel Park confirm this impression while also showing a significant afterlife to this stadium, particularly through children’s play
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