175 research outputs found

    Durable resistance to crop pathogens: an epidemiological framework to predict risk under uncertainty.

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    Increasing the durability of crop resistance to plant pathogens is one of the key goals of virulence management. Despite the recognition of the importance of demographic and environmental stochasticity on the dynamics of an epidemic, their effects on the evolution of the pathogen and durability of resistance has not received attention. We formulated a stochastic epidemiological model, based on the Kramer-Moyal expansion of the Master Equation, to investigate how random fluctuations affect the dynamics of an epidemic and how these effects feed through to the evolution of the pathogen and durability of resistance. We focused on two hypotheses: firstly, a previous deterministic model has suggested that the effect of cropping ratio (the proportion of land area occupied by the resistant crop) on the durability of crop resistance is negligible. Increasing the cropping ratio increases the area of uninfected host, but the resistance is more rapidly broken; these two effects counteract each other. We tested the hypothesis that similar counteracting effects would occur when we take account of demographic stochasticity, but found that the durability does depend on the cropping ratio. Secondly, we tested whether a superimposed external source of stochasticity (for example due to environmental variation or to intermittent fungicide application) interacts with the intrinsic demographic fluctuations and how such interaction affects the durability of resistance. We show that in the pathosystem considered here, in general large stochastic fluctuations in epidemics enhance extinction of the pathogen. This is more likely to occur at large cropping ratios and for particular frequencies of the periodic external perturbation (stochastic resonance). The results suggest possible disease control practises by exploiting the natural sources of stochasticity.GL is funded by the ESPA award “Dynamic Drivers of Disease in Africa Consortium”. The work of FvdB is supported by Rothamsted Research, who receives grant aided assistance from the Biological and Biotechnological Research Council of the United Kingdom. CAG gratefully acknowledges the support of a BBSRC Professorial Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.pcbi.100287

    Migration and divisions:thoughts on (anti-) narrativity in visual representations of mobile people

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    This article developed as part of a dialogue between the two authors. The dialogue was sparked off by MARLEY's response to a seminar presentation by GILLIGAN. In keeping with its origins we have retained the dialogue format. The article focuses on two sets of images—one a still image taken by a photojournalist, the other a sequence of stills taken by one of the authors. The authors use these images to explore the question "what imbues an image with narrative content?" and to explore the possibilities for developing a positive visual representation which promotes the idea of open borders. The article draws on linguistic theory to explore the grammar of visual narrative and relates this to the issue of the visual representation of immigration in contemporary Europe

    Launch Vehicle Manual Steering with Adaptive Augmenting Control:In-Flight Evaluations of Adverse Interactions Using a Piloted Aircraft

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    An Adaptive Augmenting Control (AAC) algorithm for the Space Launch System (SLS) has been developed at the Marshall Space Flight Center (MSFC) as part of the launch vehicle's baseline flight control system. A prototype version of the SLS flight control software was hosted on a piloted aircraft at the Armstrong Flight Research Center to demonstrate the adaptive controller on a full-scale realistic application in a relevant flight environment. Concerns regarding adverse interactions between the adaptive controller and a potential manual steering mode were also investigated by giving the pilot trajectory deviation cues and pitch rate command authority, which is the subject of this paper. Two NASA research pilots flew a total of 25 constant pitch rate trajectories using a prototype manual steering mode with and without adaptive control, evaluating six different nominal and off-nominal test case scenarios. Pilot comments and PIO ratings were given following each trajectory and correlated with aircraft state data and internal controller signals post-flight

    1. Lumbosacral radicular pain

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    Introduction: Patients suffering lumbosacral radicular pain report radiating pain in one or more lumbar or sacral dermatomes. In the general population, low back pain with leg pain extending below the knee has an annual prevalence that varies from 9.9% to 25%. Methods: The literature on the diagnosis and treatment of lumbosacral radicular pain was reviewed and summarized. Results: Although a patient's history, the pain distribution pattern, and clinical examination may yield a presumptive diagnosis of lumbosacral radicular pain, additional clinical tests may be required. Medical imaging studies can demonstrate or exclude specific underlying pathologies and identify nerve root irritation, while selective diagnostic nerve root blocks can be used to confirm the affected level(s). In subacute lumbosacral radicular pain, transforaminal corticosteroid administration provides short-term pain relief and improves mobility. In chronic lumbosacral radicular pain, pulsed radiofrequency (PRF) treatment adjacent to the spinal ganglion (DRG) can provide pain relief for a longer period in well-selected patients. In cases of refractory pain, epidural adhesiolysis and spinal cord stimulation can be considered in experienced centers. Conclusions: The diagnosis of lumbosacral radicular pain is based on a combination of history, clinical examination, and additional investigations. Epidural steroids can be considered for subacute lumbosacral radicular pain. In chronic lumbosacral radicular pain, PRF adjacent to the DRG is recommended. SCS and epidural adhesiolysis can be considered for cases of refractory pain in specialized centers.</p

    Interventions for improving medical students' interpersonal communication in medical consultations

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    Background Communication is a common element in all medical consultations, affecting a range of outcomes for doctors and patients. The increasing demand for medical students to be trained to communicate effectively has seen the emergence of interpersonal communication skills as core graduate competencies in medical training around the world. Medical schools have adopted a range of approaches to develop and evaluate these competencies. Objectives To assess the effects of interventions for medical students that aim to improve interpersonal communication in medical consultations. Search methods We searched five electronic databases: Cochrane Central Register of Controlled Trials, MEDLINE, Embase, PsycINFO, and ERIC (Educational Resource Information Centre) in September 2020, with no language, date, or publication status restrictions. We also screened reference lists of relevant articles and contacted authors of included studies. Selection criteria We included randomised controlled trials (RCTs), cluster‐RCTs (C‐RCTs), and non‐randomised controlled trials (quasi‐RCTs) evaluating the effectiveness of interventions delivered to students in undergraduate or graduate‐entry medical programmes. We included studies of interventions aiming to improve medical students’ interpersonal communication during medical consultations. Included interventions targeted communication skills associated with empathy, relationship building, gathering information, and explanation and planning, as well as specific communication tasks such as listening, appropriate structure, and question style. Data collection and analysis We used standard methodological procedures expected by Cochrane. Two review authors independently reviewed all search results, extracted data, assessed the risk of bias of included studies, and rated the quality of evidence using GRADE. Main results We found 91 publications relating to 76 separate studies (involving 10,124 students): 55 RCTs, 9 quasi‐RCTs, 7 C‐RCTs, and 5 quasi‐C‐RCTs. We performed meta‐analysis according to comparison and outcome. Among both effectiveness and comparative effectiveness analyses, we separated outcomes reporting on overall communication skills, empathy, rapport or relationship building, patient perceptions/satisfaction, information gathering, and explanation and planning. Overall communication skills and empathy were further divided as examiner‐ or simulated patient‐assessed. The overall quality of evidence ranged from moderate to very low, and there was high, unexplained heterogeneity. Overall, interventions had positive effects on most outcomes, but generally small effect sizes and evidence quality limit the conclusions that can be drawn. Communication skills interventions in comparison to usual curricula or control may improve both overall communication skills (standardised mean difference (SMD) 0.92, 95% confidence interval (CI) 0.53 to 1.31; 18 studies, 1356 participants; I² = 90%; low‐quality evidence) and empathy (SMD 0.64, 95% CI 0.23 to 1.05; 6 studies, 831 participants; I² = 86%; low‐quality evidence) when assessed by experts, but not by simulated patients. Students’ skills in information gathering probably also improve with educational intervention (SMD 1.07, 95% CI 0.61 to 1.54; 5 studies, 405 participants; I² = 78%; moderate‐quality evidence), but there may be little to no effect on students' rapport (SMD 0.18, 95% CI ‐0.15 to 0.51; 9 studies, 834 participants; I² = 81%; low‐quality evidence), and effects on information giving skills are uncertain (very low‐quality evidence). We are uncertain whether experiential interventions improve overall communication skills in comparison to didactic approaches (SMD 0.08, 95% CI ‐0.02 to 0.19; 4 studies, 1578 participants; I² = 4%; very low‐quality evidence). Electronic learning approaches may have little to no effect on students’ empathy scores (SMD ‐0.13, 95% CI ‐0.68 to 0.43; 3 studies, 421 participants; I² = 82%; low‐quality evidence) or on rapport (SMD 0.02, 95% CI ‐0.33 to 0.38; 3 studies, 176 participants; I² = 19%; moderate‐quality evidence) compared to face‐to‐face approaches. There may be small negative effects of electronic interventions on information giving skills (low‐quality evidence), and effects on information gathering skills are uncertain (very low‐quality evidence). Personalised/specific feedback probably improves overall communication skills to a small degree in comparison to generic or no feedback (SMD 0.58, 95% CI 0.29 to 0.87; 6 studies, 502 participants; I² = 56%; moderate‐quality evidence). There may be small positive effects of personalised feedback on empathy and information gathering skills (low quality), but effects on rapport are uncertain (very low quality), and we found no evidence on information giving skills. We are uncertain whether role‐play with simulated patients outperforms peer role‐play in improving students’ overall communication skills (SMD 0.17, 95% CI ‐0.33 to 0.67; 4 studies, 637 participants; I² = 87%; very low‐quality evidence). There may be little to no difference between effects of simulated patient and peer role‐play on students' empathy (low‐quality evidence) with no evidence on other outcomes for this comparison. Descriptive syntheses of results that could not be included in meta‐analyses across outcomes and comparisons were mixed, as were effects of different interventions and comparisons on specific communication skills assessed by the included trials. Quality of evidence was downgraded due to methodological limitations across several risk of bias domains, high unexplained heterogeneity, and imprecision of results. In general, results remain consistent in sensitivity analysis based on risk of bias and adjustment for clustering. No adverse effects were reported. Authors' conclusions This review represents a substantial body of evidence from which to draw, but further research is needed to strengthen the quality of the evidence base, to consider the long‐term effects of interventions on students’ behaviour as they progress through training and into practice, and to assess effects of interventions on patient outcomes. Efforts to standardise assessment and evaluation of interpersonal skills will strengthen future research efforts
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