Probabilistic sensitivity analysis of optimized preventive maintenance strategies for deteriorating infrastructure assets

Efficient life-cycle management of civil infrastructure systems under continuous deterioration can be improved by studying the sensitivity of optimised preventive maintenance decisions with respect to changes in model parameters. Sensitivity analysis in maintenance optimisation problems is important because if the calculation of the cost of preventive maintenance strategies is not sufficiently robust, the use of the maintenance model can generate optimised maintenances strategies that are not cost-effective. Probabilistic sensitivity analysis methods (particularly variance based ones), only partially respond to this issue and their use is limited to evaluating the extent to which uncertainty in each input contributes to the overall output's variance. These methods do not take account of the decision-making problem in a straightforward manner. To address this issue, we use the concept of the Expected Value of Perfect Information (EVPI) to perform decision-informed sensitivity analysis: to identify the key parameters of the problem and quantify the value of learning about certain aspects of the life-cycle management of civil infrastructure system. This approach allows us to quantify the benefits of the maintenance strategies in terms of expected costs and in the light of accumulated information about the model parameters and aspects of the system, such as the ageing process. We use a Gamma process model to represent the uncertainty associated with asset deterioration, illustrating the use of EVPI to perform sensitivity analysis on the optimisation problem for age-based and condition-based preventive maintenance strategies. The evaluation of EVPI indices is computationally demanding and Markov Chain Monte Carlo techniques would not be helpful. To overcome this computational difficulty, we approximate the EVPI indices using Gaussian process emulators. The implications of the worked numerical examples discussed in the context of analytical efficiency and organisational learning

Never events in UK general practice: a survey of the views of general practitioners on their frequency and acceptability as a safety improvement approach

Background: Never events (NEs) are serious preventable patient safety incidents and are a component of formal quality and safety improvement (Q&SI) policies in the United Kingdom and elsewhere. A preliminary list of NEs for UK general practice has been developed, but the frequency of these events, or their acceptability to general practitioner (GPs) as a Q&SI approach, is currently unknown. The study aims to estimate (1) the frequency of 10 NEs occurring within GPs' own practices and (2) the extent to which the NE approach is perceived as acceptable for use. Methods: General practitioners were surveyed, and mixed-effects logistic regression models examined the relationship between GP opinions of NE, estimates of NE frequency, and the characteristics of the GPs and their practices. Results: Responses from 556 GPs in 412 practices were analyzed. Most participants (70%-88%, depending on the NE) agreed that the described incident should be designated as a NE. Three NEs were estimated to have occurred in less than 4% of practices in the last year; however, two NEs were estimated to have occurred in 45% to 61% of the practices. General practitioners reporting that a NE had occurred in their practice in the last year were significantly less likely to agree with the designation as a NE compared with GPs not reporting a NE (odds ratio, 0.42; 95% CI = 0.36-0.49). Conclusions: The NE approach may have Q&SI potential for general practice, but further work to adapt the concept and content is required

Patient acceptance and perceived utility of pre-consultation prevention summaries and reminders in general practice: pilot study

Extent: 8p.BACKGROUND: Patients attending general practices receive only about sixty per cent of the preventive services that are indicated for them. This pilot study explores patient acceptability and perceived utility of automatically generated prevention summary and reminder sheets provided to patients immediately before consultations with their general practitioners. METHODS: Adult patients attending a general practitioner in a practice in Adelaide and a general practitioner in a practice in Melbourne, Australia for consultations in January and February 2009 received automatically-generated prevention summary and reminder sheets that highlighted indicated preventive activities that were due to be performed, and that encouraged the patient to discuss these with the general practitioner in the consultation. Patients completed a post-consultation questionnaire and were interviewed about their experience of receiving the sheets. RESULTS: Sixty patients, median age 53 years (interquartile range 40-74) years, and 58% female, were recruited. Seventy eight per cent of patients found the sheets clear and easy to understand, 75% found them very or quite useful, 72% reported they had addressed with their general practitioner all of the preventive activities that were listed on the sheets as being due to be performed. A further 13% indicated that they had addressed most or some of the activities. 78% of patients said that they would like to keep receiving the sheets. Themes emerging from interviews with patients included: patient knowledge was enhanced; patient conceptions of health and the GP consultation were broadened; the consultation was enhanced; patient pro-activity was encouraged; patients were encouraged to plan their health care; the intervention was suitable for a variety of patients. CONCLUSIONS: Most patients reported that they found the prevention summary and reminder sheets acceptable and useful. The actual increase in performance of preventive activities that may result from this new intervention needs to be tested in randomised controlled trials.Oliver R. Frank, Nigel P. Stocks and Paul Aylwar

Making the Transition: Reflection, Ownership and Agency in Academic Writing

English academic discourse is commonly characterised as objective and depersonalised. Yet at the centre of each student essay is an embodied subject who brings their own histories, affective responses and agency to their writing. This dimension may easily be overlooked in process-based approaches to teaching essay writing. We considered whether foregrounding the subjective aspects of writing implicit in a standard essay might encourage students to engage more meaningfully with the task and develop a stronger authorial voice. Hence, a reflective journal was designed to enhance essay writing for students studying on an international pre-master’s programme at Goldsmiths, University of London. The reflective journal is intended as a “transitional space” (Winnicott 2005) between the student writer and the essay task, allowing the subjective dimension in the writing process to be made visible, even if this would ultimately be effaced in the final essay. This paper will report on the context, rationale and experience of using this reflective journal, illustrated with a case study showing one student’s progress from the personal to the critical

When Arts Meet Enterprise: Transdisciplinarity, Students’ Identities and EAP

This paper reports on a qualitative study investigating the experience and perspectives of students using English as an international language studying transdisciplinary master's degrees related to culture industries at Goldsmiths, University of London. The particular focus of this paper concerns their experiences of writing several different genres on their degree programmes, including a category of written assessment that, in keeping with the transdisciplinary project of opening up disciplinary borders, transgresses typical genre parameters. We argue that (increasingly popular) transdisciplinary programmes of this kind challenge preconceived expectations about academic writing and require a high tolerance of ambiguity on the part of both students and EAP lecturers: established genre conventions may be destabilized and writing become a precarious yet inherently creative process. Our findings highlight the significance of students' identities with regard to negotiating these written assessments; they support the view that academic literacies' emphasis on student perspectives enriches text-oriented EAP pedagogy, and that insights gleaned from small-scale ethnographic studies of this kind enhance the embedding of subject-specific EAP academic writing development

Spatial Epidemiology: Current Approaches and Future Challenges

Spatial epidemiology is the description and analysis of geographic variations in disease with respect to demographic, environmental, behavioral, socioeconomic, genetic, and infectious risk factors. We focus on small-area analyses, encompassing disease mapping, geographic correlation studies, disease clusters, and clustering. Advances in geographic information systems, statistical methodology, and availability of high-resolution, geographically referenced health and environmental quality data have created unprecedented new opportunities to investigate environmental and other factors in explaining local geographic variations in disease. They also present new challenges. Problems include the large random component that may predominate disease rates across small areas. Though this can be dealt with appropriately using Bayesian statistics to provide smooth estimates of disease risks, sensitivity to detect areas at high risk is limited when expected numbers of cases are small. Potential biases and confounding, particularly due to socioeconomic factors, and a detailed understanding of data quality are important. Data errors can result in large apparent disease excess in a locality. Disease cluster reports often arise nonsystematically because of media, physician, or public concern. One ready means of investigating such concerns is the replication of analyses in different areas based on routine data, as is done in the United Kingdom through the Small Area Health Statistics Unit (and increasingly in other European countries, e.g., through the European Health and Environment Information System collaboration). In the future, developments in exposure modeling and mapping, enhanced study designs, and new methods of surveillance of large health databases promise to improve our ability to understand the complex relationships of environment to health

The role of colonization in establishing patterns of community composition and diversity in shallow-water sedimentary communities

To determine whether pattern and diversity in benthic sedimentary communities are set primarily at colonization or by post-settlement biological interactions, we collected faunal cores and conducted reciprocal sediment transplant experiments at a sandy and a muddy site at 12 m depth, ~3 km apart off New Jersey. Multivariate analyses of cores collected at these sites in September 1994 indicated differences in the taxa determining local pattern, with the bivalve Spisula solidissima and the polychaete Polygordius sp. being dominant at the sandy site, and oligochaetes, several polychaete species and the bivalve Nucula annulata dominant at the muddy site. Individual cores from the sandy site were significantly less diverse than those at the muddy site. Short-term experiments (3-5 d) were deployed by divers at three different times (August-September, 1994). Replicate trays (100 cm2) filled with azoic sand or mud were placed flush with the ambient seafloor at both sites. Multivariate comparisons indicated that sediment treatment in trays played a greater role in determining colonization patterns in the first experiment, site played a greater role in the second, and both variables contributed in the third. This pattern suggests that larval settlement and habitat choice played an important role in the first and third experiments, and that local transport of recently settled juveniles from the surrounding sediments was important in the second and third experiments. Sandy-site trays had significantly lower diversity than muddy-site trays, but there was no effect of sediment type in trays on diversity of colonizers. These experiments focused on small spatial scales and three short time periods, but they demonstrate that species patterns in some environments may be set by habitat selection by larvae and by juvenile colonization from the surrounding community. Post-colonization processes such as predation and competition likely play a major role for some species, but patterns of initial colonization corresponded well with those in the local community

Novel quinazolinone inhibitors of the Pseudomonas aeruginosa quorum sensing transcriptional regulator PqsR

© 2020 The Authors Rising numbers of cases of multidrug- and extensively drug-resistant Pseudomonas aeruginosa over recent years have created an urgent need for novel therapeutic approaches to cure potentially fatal infections. One such approach is virulence attenuation where anti-virulence compounds, designed to reduce pathogenicity without affording bactericidal effects, are employed to treat infections. P. aeruginosa uses the pqs quorum sensing (QS) system, to coordinate the expression of a large number of virulence determinants as well as bacterial-host interactions and hence represents an excellent anti-virulence target. We report the synthesis and identification of a new series of thiazole-containing quinazolinones capable of inhibiting PqsR, the transcriptional regulator of the pqs QS system. The compounds demonstrated high potency (IC50 < 300 nM) in a whole-cell assay, using a mCTX:PpqsA-lux-based bioreporter for the P. aeruginosa PAO1-L and PA14 strains. Structural evaluation defined the binding modes of four analogues in the ligand-binding domain of PqsR through X-ray crystallography. Further work showed the ability of 6-chloro-3((2-pentylthiazol-4-yl)methyl)quinazolin-4(3H)-one (18) and 6-chloro-3((2-hexylthiazol-4-yl)methyl)quinazolin-4(3H)-one (19) to attenuate production of the PqsR-regulated virulence factor pyocyanin. Compounds 18 and 19 showed a low cytotoxic profile in the A549 human epithelial lung cell line making them suitable candidates for further pre-clinical evaluation