1,249 research outputs found
On the Expressivity and Applicability of Model Representation Formalisms
A number of first-order calculi employ an explicit model representation
formalism for automated reasoning and for detecting satisfiability. Many of
these formalisms can represent infinite Herbrand models. The first-order
fragment of monadic, shallow, linear, Horn (MSLH) clauses, is such a formalism
used in the approximation refinement calculus. Our first result is a finite
model property for MSLH clause sets. Therefore, MSLH clause sets cannot
represent models of clause sets with inherently infinite models. Through a
translation to tree automata, we further show that this limitation also applies
to the linear fragments of implicit generalizations, which is the formalism
used in the model-evolution calculus, to atoms with disequality constraints,
the formalisms used in the non-redundant clause learning calculus (NRCL), and
to atoms with membership constraints, a formalism used for example in decision
procedures for algebraic data types. Although these formalisms cannot represent
models of clause sets with inherently infinite models, through an additional
approximation step they can. This is our second main result. For clause sets
including the definition of an equivalence relation with the help of an
additional, novel approximation, called reflexive relation splitting, the
approximation refinement calculus can automatically show satisfiability through
the MSLH clause set formalism.Comment: 15 page
A global disorder of imprinting in the human female germ line
Imprinted genes are expressed differently depending on whether they are carried by a chromosome of maternal or paternal origin. Correct imprinting is established by germline-specific modifications; failure of this process underlies several inherited human syndromes. All these imprinting control defects are cis-acting, disrupting establishment or maintenance of allele-specific epigenetic modifications across one contiguous segment of the genome. In contrast, we report here an inherited global imprinting defect. This recessive maternal-effect mutation disrupts the specification of imprints at multiple, non-contiguous loci, with the result that genes normally carrying a maternal methylation imprint assume a paternal epigenetic pattern on the maternal allele. The resulting conception is phenotypically indistinguishable from an androgenetic complete hydatidiform mole, in which abnormal extra-embryonic tissue proliferates while development of the embryo is absent or nearly so. This disorder offers a genetic route to the identification of trans-acting oocyte factors that mediate maternal imprint establishment
Agent based modelling for water resource allocation in the transboundary Nile river
© 2016 by the authors.Water resource allocation is the process of assessing and determining a mechanism on how water should be distributed among different regions, sectors and users. Over the recent decades, the optimal solution for water resource allocation has been explored both in centralised and decentralised mechanisms. Conventional approaches are under central planner suggesting a solution which maximises total welfare to the users. Moving towards the decentralised modelling, the techniques consider individuals as if they act selfishly in their own favour. While central planner provides an efficient solution, it may not be acceptable for some selfish agents. The contrary is true as well in decentralised solution, where the solution lacks efficiency leading to an inefficient usage of provided resources. This paper develops a parallel evolutionary search algorithm to introduce a mechanism in re-distributing the central planner revenue value among the competing agents based on their contribution to the central solution. The result maintains the efficiency and is used as an incentive for calculating a fair revenue for each agent. The framework is demonstrated and discussed to allocate water resources along the Nile river basin, where there exist eleven competing users represented as agents in various sectors with upstream-downstream relationships and different water demands and availability
Reduced Risk of Malaria Parasitemia Following Household Screening and Treatment: A Cross-Sectional and Longitudinal Cohort Study
BACKGROUND: In regions of declining malaria transmission, new strategies for control are needed to reduce transmission and achieve elimination. Artemisinin-combination therapy (ACT) is active against immature gametocytes and can reduce the risk of transmission. We sought to determine whether household screening and treatment of infected individuals provides protection against infection for household members. METHODOLOGY/PRINCIPAL FINDINGS: The study was conducted in two areas in Southern Province, Zambia in 2007 and 2008/2009. To determine the impact of proactive case detection, households were randomly selected either to join a longitudinal cohort, in which participants were repeatedly screened throughout the year and those infected treated with artemether-lumefantrine, or a cross-sectional survey, in which participants were visited only once. Cross-sectional surveys were conducted throughout the year. The prevalence of RDT positivity was compared between the longitudinal and cross-sectional households at baseline and during follow-up using multilevel logistic regression. In the 2007 study area, 174 and 156 participants enrolled in the cross-sectional and longitudinal groups, respectively. In the 2008/2009 study area, 917 and 234 participants enrolled in the cross-sectional and longitudinal groups, respectively. In both study areas, participants and households in the longitudinal and cross-sectional groups were similar on demographic characteristics and prevalence of RDT positivity at baseline (2007: ORâ=â0.97; 95% CI:0.46, 2.03 | 2008/2009: ORâ=â1.28; 95% CI:0.44, 3.79). After baseline, the prevalence of RDT positivity was significantly lower in longitudinal compared to cross-sectional households in both study areas (2007: ORâ=â0.44; 95% CI:0.20, 0.96 | 2008/2009: ORâ=â0.16; 95% CI:0.05, 0.55). CONCLUSIONS/SIGNIFICANCE: Proactive case detection, consisting of screening household members with an RDT and treating those positive with ACT, can reduce transmission and provide indirect protection to household members. A targeted test and treat strategy could contribute to the elimination of malaria in regions of low transmission
Role-play for medical students learning about communication: Guidelines for maximising benefits
BACKGROUND: Role-play is widely used as an educational method for learning about communication in medical education. Although educational theory provides a sound rationale for using this form of simulation, there is little published evidence for its effectiveness. Students' prior experiences of role-play may influence the way in which they engage in this method. This paper explores students' experiences with the aim of producing guidelines for maximising the benefits of role-play within this learning context. METHODS: First-year undergraduate medical students participated in a role-play session as part of their communication programme. Before and after the session, students completed questionnaires. In the pre-session questionnaire, students were asked about their experiences of role-play and asked to identify helpful and unhelpful elements. Immediately after the session, students answered similar questions in relation to the role-play activity they had just completed. Descriptive statistics were used to analyse quantitative data and qualitative data was thematically analysed. RESULTS: 284 students completed evaluation forms. Although 63 (22.2%) had prior unhelpful experiences, most students (n = 274; 96.5%) found this experience helpful. Summary findings were that students reported the key aspects of helpful role-play were opportunities for observation, rehearsal and discussion, realistic roles and alignment of roles with other aspects of the curriculum. Unhelpful aspects were those that evoked strong negative emotional responses and factors that contributed to a lack of realism. CONCLUSION: Role-play was valued by students in the acquisition of communication skills even though some had prior unhelpful experiences. Guidelines for effective role-play include adequate preparation, alignment of roles and tasks with level of practice, structured feedback guidelines and acknowledgment of the importance of social interactions for learning
Challenges in Semileptonic B Decays
Two of the elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix,
and , are extracted from semileptonic B decays. The
results of the B factories, analysed in the light of the most recent
theoretical calculations, remain puzzling, because for both and
the exclusive and inclusive determinations are in clear tension.
Further, measurements in the channels at Belle, Babar, and LHCb show
discrepancies with the Standard Model predictions, pointing to a possible
violation of lepton flavor universality. LHCb and Belle II have the potential
to resolve these issues in the next few years. This article summarizes the
discussions and results obtained at the MITP workshop held on April 9--13,
2018, in Mainz, Germany, with the goal to develop a medium-term strategy of
analyses and calculations aimed at solving the puzzles. Lattice and continuum
theorists working together with experimentalists have discussed how to reshape
the semileptonic analyses in view of the much higher luminosity expected at
Belle II, searching for ways to systematically validate the theoretical
predictions in both exclusive and inclusive B decays, and to exploit the rich
possibilities at LHCb.Comment: 76 page
The effects of crew resource management on teamwork and safety climate at Veterans Health Administration facilities
Communication failure is a significant source of adverse events in health care and a leading root cause of sentinel events reported to the Joint Commission. The Veterans Health Administration National Center for Patient Safety established Clinical Team Training (CTT) as a comprehensive program to enhance patient safety and to improve communication and teamwork among health care professionals. CTT is based on techniques used in aviationâs Crew Resource Management (CRM) training. The aviation industry has reached a significant safety record in large part related to the culture change generated by CRM and sustained by its recurrent implementation. This article focuses on the improvement of communication, teamwork, and patient safety by utilizing a standardized, CRMâbased, interprofessional, immersive training in diverse clinical areas. The Teamwork and Safety Climate Questionnaire was used to evaluate safety climate before and after CTT. The scores for all of the 27 questions on the questionnaire showed an increase from baseline to 12 months, and 11 of those increases were statistically significant. A recurrent training is recommended to maintain the positive outcomes. CTT enhances patient safety and reduces risk of patient harm by improving teamwork and facilitating clear, concise, specific and timely communication among health care professionals.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145421/1/jhrm21292_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145421/2/jhrm21292.pd
Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy
Background
A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets.
Methods
Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendallâs tau for dichotomous variables, or JonckheereâTerpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis.
Results
A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both pâ<â0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROCâ=â0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all pâ<â0.001).
Conclusion
We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty
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