Modal Logics of Topological Relations

Logical formalisms for reasoning about relations between spatial regions play a fundamental role in geographical information systems, spatial and constraint databases, and spatial reasoning in AI. In analogy with Halpern and Shoham's modal logic of time intervals based on the Allen relations, we introduce a family of modal logics equipped with eight modal operators that are interpreted by the Egenhofer-Franzosa (or RCC8) relations between regions in topological spaces such as the real plane. We investigate the expressive power and computational complexity of logics obtained in this way. It turns out that our modal logics have the same expressive power as the two-variable fragment of first-order logic, but are exponentially less succinct. The complexity ranges from (undecidable and) recursively enumerable to highly undecidable, where the recursively enumerable logics are obtained by considering substructures of structures induced by topological spaces. As our undecidability results also capture logics based on the real line, they improve upon undecidability results for interval temporal logics by Halpern and Shoham. We also analyze modal logics based on the five RCC5 relations, with similar results regarding the expressive power, but weaker results regarding the complexity

Search for lepton flavor violating decays of a heavy neutral particle in p-pbar collisions at root(s)=1.8 TeV

We report on a search for a high mass, narrow width particle that decays directly to e+mu, e+tau, or mu+tau. We use approximately 110 pb^-1 of data collected with the Collider Detector at Fermilab from 1992 to 1995. No evidence of lepton flavor violating decays is found. Limits are set on the production and decay of sneutrinos with R-parity violating interactions.Comment: Figure 2 fixed. Reference 4 fixed. Minor changes to tex

Lifting the lid: a clinical audit on commode cleaning

Many healthcare-associated infections (HCAIs) are preventable by infection control procedures designed to interrupt the transmission of organisms from a source. Commodes are in use constantly throughout healthcare facilities. Therefore commode surfaces are constantly handled, and any pathogens present have the potential to be transferred to not only other surfaces but also, more importantly, to patients, thus compromising patient safety. In order to examine the effectiveness and thoroughness of cleaning commodes an audit was undertaken to assess compliance with evidence-based practice. This audit demonstrates a cycle which includes defining best practice, implementing best practice, monitoring best practice and taking action to improve practice. The audit results confirmed an issue that the authors had long suspected. That is, that commodes allocated to individual patients are not always cleaned after every use. Using adenosine triphosphate (ATP) bioluminescence as an indicator of organic soiling also demonstrated that commodes that were considered clean were not always cleaned to a high standard. Implementing the audit recommendations improves staff knowledge through education, standardises cleaning procedures and ultimately improves patient safety

Short-Term Effects of Air Pollution on Wheeze in Asthmatic Children in Fresno, California

BACKGROUND: Although studies have demonstrated that air pollution is associated with exacerbation of asthma symptoms in children with asthma, little is known about the susceptibility of subgroups, particularly those with atopy. OBJECTIVE: This study was designed to evaluate our a priori hypothesis that identifiable subgroups of asthmatic children are more likely to wheeze with exposure to ambient air pollution. METHODS: A cohort of 315 children with asthma, 6-11 years of age, was recruited for longitudinal follow-up in Fresno, California (USA). During the baseline visit, children were administered a respiratory symptom questionnaire and allergen skin-prick test. Three times a year, participants completed 14-day panels during which they answered symptom questions twice daily. Ambient air quality data from a central monitoring station were used to assign exposures to the following pollutants: particulate matter <= 2.5 mu m in aerodynamic diameter, particulate matter between 2.5 and 10 mu m in aerodynamic diameter (PM(10-2.5)), elemental carbon, nitrogen dioxide (NO(2)), nitrate, and O(3). RESULTS: For the group as a whole, wheeze was significantly associated with short-term exposures to NO(2) [odds ratio (OR) = 1.10 for 8.7-ppb increase; 95% confidence interval (CI), 1.02-1.20] and PM(10-2.5) (OR = 1.11 for 14.7-mu g/m(3) increase; 95% CI, 1.01-1.22). The association with wheeze was stronger for these two pollutants in children who were skin-test positive to cat or common fungi and in boys with mild intermittent asthma. CONCLUSION: A pollutant associated with traffic emissions, NO(2), and a pollutant with bioactive constituents, PM(10-2.5), were associated with increased risk of wheeze in asthmatic children living in Fresno, California. Children with atopy to cat or common fungi and boys with mild intermittent asthma were the subgroups for which we observed the largest associations

Factors underlying Ebola virus infection among health workers, Kenema, Sierra Leone, 2014-2015

Background. Ebola virus disease (EVD) in health workers (HWs) has been a major challenge during the 2014-2015 outbreak. We examined factors associated with Ebola virus exposure and mortality in HWs in Kenema District, Sierra Leone. Methods. We analyzed data from the Sierra Leone National Viral Hemorrhagic Fever Database, contact tracing records, Kenema Government Hospital (KGH) staff and Ebola Treatment Unit (ETU) rosters, and burial logs.Results. From May 2014 through January 2015, 600 cases of EVD originated in Kenema District, including 92 (15%) HWs, 66 (72%) of whom worked at KGH. Among KGH medical staff and international volunteers, 18 of 62 (29%) who worked in the ETU developed EVD, compared with 48 of 83 (58%) who worked elsewhere in the hospital. Thirteen percent of HWs with EVD reported contact with EVD patients, while 27% reported contact with other infected HWs. The number of HW EVD cases at KGH declined roughly 1 month after implementation of a new triage system at KGH and the opening of a second ETU within the district. The case fatality ratio for HWs and non-HWs with EVD was 69% and 74%, respectively.Conclusions. The cluster of HW EVD cases in Kenema District is one of the largest ever reported. Most HWs with EVD had potential virus exposure both inside and outside of hospitals. Prevention measures for HWs must address a spectrum of infection risks in both formal and informal care settings as well as in the community.Publisher PDFPeer reviewe

Telephone survey of private patients' views on continuity of care and registration with general practice in Ireland

BACKGROUND: The desire of patients for personal continuity of care with a General Practitioner (GP) has been well documented, but not within non-registered private patients in Ireland. This study set out to examine the attitudes and reported behaviours of private fee-paying patients towards continuity of GP care and universal registration for patients. METHODS: Cross-sectional telephone survey of 400 randomly chosen fee-paying patients living within County Dublin. There is no formal system of registration with a GP for these patients. Main outcomes were attendance of respondents at primary health care facilities and their attitudes towards continuity of care and registration with a GP. Data was analysed using descriptive statistics and using parametric and non-parametric tests of association. Pearson correlation was used to quantify the association between the described variables and attitudes towards continuity and registration with a GP. Variables showing significance at the 5% level were entered into multiple linear regression models. RESULTS: 97% of respondents had seen a GP in the previous 5 years. The mean number of visits to the GP for respondents was 2.3 per annum. 89% of respondents had a regular GP and the mean length of time with their GP was 15.6 years. 96% preferred their personal medical care to be provided within one general practice. 16% of respondents had consulted a GP outside of their own practice in the previous year. They were more likely to be female, commute a longer distance to work or have poorer health status. 81% considered it important to be officially registered with a GP practice of their choice. CONCLUSION: Both personal and longitudinal continuity of care with a GP are important to private patients. Respondents who chose to visit GPs other than their regular GP were not easily characterised in this study and individual circumstances may lead to this behaviour. There is strong support for a system of universal patient registration within general practice

Comparing cost-effectiveness of surface water flood management interventions in a UK catchment

This is the final published version. Available from Wiley via the DOI in this record.Despite significant consequences caused by recent events, surface water flooding has historically been of lower priority relative to fluvial and coastal risks in UK flood management. Legislation and research proposes a variety of innovative interventions to address this; however, widespread application of these remains a challenge due to a number of institutional, economic, and technical barriers. This research applies a framework capable of fast and high-resolution assessment of intervention cost-effectiveness as an opportunity to improve available evidence and encourage uptake of interventions through analysing permutations of type, scale, and distribution in urban catchments. Fast assessment of many scenarios is achieved using a cellular automata flood model and a simplified representation of interventions. Conventional and green strategies are examined across a range of design standard and high-magnitude rainfall events in an urban catchment. Results indicate high-volume rainwater capture interventions demonstrate a significant reduction in estimated annual damage costs, and localised surface water drainage interventions exhibit high cost-effectiveness for damage reduction. Analysis of performance across a wide range of return periods enhances available evidence for option comparison decision support and provides a basis for future resilience assessment of interventions.Engineering and Physical Sciences Research Council (EPSRC

How Phytophthora cinnamomi became associated with the death of Eucalyptus marginata – the early investigations into jarrah dieback

The name jarrah dieback was used in the 1940s to describe a serious economic problem in the jarrah forest in the south west of Western Australia. This was the sudden death of groups of jarrah (Eucalyptus marginata) trees that occurred on previously logged sites that had a tendency to become waterlogged in winter. Although the cause was not determined at the time, from symptoms recorded in early investigations the most likely explanation is that the trees died as the result of waterlogging damage. In the 1960s it was shown that many of these sites were infested by the introduced oomycete Phytophthora cinnamomi and tree deaths, together with the deaths of many mid- and under-storey plants, were attributed to this pathogen. A chronology of the research, based on contemporary unpublished documents, shows that in 1968 the conclusion that P. cinnamomi caused jarrah deaths was not supported by the available evidence, because the work did not satisfy the first and fourth of Koch’s postulates. The evidence that P. cinnamomi killed many mid- and under-storey plants was much stronger. There are two problems that have been confused: the death of groups of jarrah trees (jarrah dieback) that is caused by waterlogging and the death of many mid- and under-storey plants (Phytophthora dieback) caused by P. cinnamomi infection