On partial order semantics for SAT/SMT-based symbolic encodings of weak memory concurrency

Concurrent systems are notoriously difficult to analyze, and technological advances such as weak memory architectures greatly compound this problem. This has renewed interest in partial order semantics as a theoretical foundation for formal verification techniques. Among these, symbolic techniques have been shown to be particularly effective at finding concurrency-related bugs because they can leverage highly optimized decision procedures such as SAT/SMT solvers. This paper gives new fundamental results on partial order semantics for SAT/SMT-based symbolic encodings of weak memory concurrency. In particular, we give the theoretical basis for a decision procedure that can handle a fragment of concurrent programs endowed with least fixed point operators. In addition, we show that a certain partial order semantics of relaxed sequential consistency is equivalent to the conjunction of three extensively studied weak memory axioms by Alglave et al. An important consequence of this equivalence is an asymptotically smaller symbolic encoding for bounded model checking which has only a quadratic number of partial order constraints compared to the state-of-the-art cubic-size encoding.Comment: 15 pages, 3 figure

Bound States of the q-Deformed AdS5 x S5 Superstring S-matrix

The investigation of the q deformation of the S-matrix for excitations on the string world sheet in AdS5 x S5 is continued. We argue that due to the lack of Lorentz invariance the situation is more subtle than in a relativistic theory in that the nature of bound states depends on their momentum. At low enough momentum |p|<E the bound states transform in the anti-symmetric representation of the super-algebra symmetry and become the solitons of the Pohlmeyer reduced theory in the relativistic limit. At a critical momentum |p|=E they become marginally unstable, and at higher momenta the stable bound states are in the symmetric representation and become the familiar magnons in the string limit as q->1. This subtlety fixes a problem involving the consistency of crossing symmetry with the relativistic limit found in earlier work. With mirror kinematics, obtained after a double Wick rotation, the bound state structure is simpler and there are no marginally unstable bound states.Comment: 25 page

Quicksort Revisited: Verifying Alternative Versions of Quicksort

© Springer International Publishing Switzerland 2016.We verify the correctness of a recursive version of Tony Hoare’s quicksort algorithm using the Hoare-logic based verification tool Dafny. We then develop a non-standard, iterative version which is based on a stack of pivot-locations rather than the standard stack of ranges. We outline an incomplete Dafny proof for the latter

Care staff and family member perspectives on quality of life in people with very severe dementia in long-term care: a cross-sectional study.

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Little is known about the quality of life of people with very severe dementia in long-term care settings, and more information is needed about the properties of quality of life measures aimed at this group. In this study we explored the profiles of quality of life generated through proxy ratings by care staff and family members using the Quality of Life in Late-stage Dementia (QUALID) scale, examined factors associated with these ratings, and further investigated the psychometric properties of the QUALID. METHODS: Proxy ratings of quality of life using the QUALID were obtained for 105 residents with very severe dementia, categorised as meeting criteria for Functional Assessment Staging (FAST) stages 6 or 7, from members of care staff (n = 105) and family members (n = 73). A range of resident and staff factors were also assessed. RESULTS: Care staff and family member ratings were similar but were associated with different factors. Care staff ratings were significantly predicted by resident mood and awareness/responsiveness. Family member ratings were significantly predicted by use of antipsychotic medication. Factor analysis of QUALID scores suggested a two-factor solution for both care staff ratings and family member ratings. CONCLUSIONS: The findings offer novel evidence about predictors of care staff proxy ratings of quality of life and demonstrate that commonly-assessed resident variables explain little of the variability in family members' proxy ratings. The findings provide further information about the psychometric properties of the QUALID, and support the applicability of the QUALID as a means of examining quality of life in very severe dementia.LC: Higher Education Funding Council for Wales. CQ: National Institute for Social Care and Health Research and Economic & Social Research Council/ National Institute for Health Research. ZH: National Institute for Social Care and Health Research. RW: National Institute for Social Care and Health Research. RTW: Higher Education Funding Council for Wale

Understanding quantitative research: part 2

This article, which is the second in a two-part series, provides an introduction to understanding quantitative research, basic statistics and terminology used in research articles. Understanding statistical analysis will ensure that nurses can assess the credibility and significance of the evidence reported. This article focuses on explaining common statistical terms and the presentation of statistical data in quantitative research

"Boring formal methods" or "Sherlock Holmes deduction methods"?

This paper provides an overview of common challenges in teaching of logic and formal methods to Computer Science and IT students. We discuss our experiences from the course IN3050: Applied Logic in Engineering, introduced as a "logic for everybody" elective course at at TU Munich, Germany, to engage pupils studying Computer Science, IT and engineering subjects on Bachelor and Master levels. Our goal was to overcome the bias that logic and formal methods are not only very complicated but also very boring to study and to apply. In this paper, we present the core structure of the course, provide examples of exercises and evaluate the course based on the students' surveys.Comment: Preprint. Accepted to the Software Technologies: Applications and Foundations (STAF 2016). Final version published by Springer International Publishing AG. arXiv admin note: substantial text overlap with arXiv:1602.0517

A pilot randomised controlled trial of personalised care after treatment for prostate cancer (TOPCAT-P): nurse-led holistic-needs assessment and individualised psychoeducational intervention: study protocol

INTRODUCTION. Prostate cancer is common and the incidence is increasing, but more men are living longer after diagnosis, and die with their disease rather than of it. Nonetheless, specific and substantial physical, sexual, emotional and mental health problems often lead to a poor quality of life. Urology services increasingly struggle to cope with the demands of follow-up care, and primary care is likely to play the central role in long-term follow-up. The present phase II trial will evaluate the feasibility and acceptability of a nurse-led, person-centred psychoeducational intervention, delivered in community or primary care settings. METHODS AND ANALYSIS. Prostate cancer survivors diagnosed in the past 9-48 months and currently biochemically stable will be identified from hospital records by their treating clinician. Eligible men would have either completed radical treatment, or would be followed up with prostate specific antigen monitoring and symptom reporting. We will recruit 120 patients who will be randomised to receive either an augmented form of usual care, or an additional nurse-led intervention for a period of 36 weeks. Following the health policy in Wales, the intervention is offered by a key worker, is promoting prudent healthcare and is using a holistic needs assessment. Outcome measures will assess physical symptoms, psychological well-being, confidence in managing own health and quality of life. Healthcare service use will be measured over 36 weeks. Feedback interviews with patients and clinicians will further inform the acceptability of the intervention. Recruitment, attrition, questionnaire completion rates and outcome measures variability will be assessed, and results will inform the design of a future phase III trial and accompanying economic evaluation. ETHICS AND DISSEMINATION. Ethics approval was granted by Bangor University and North Wales REC (13/WA/0291). Results will be reported in peer-reviewed publications, at scientific conferences, and directly through national cancer and primary care networks. TRIAL REGISTRATION NUMBER. ISRCTN 34516019

Hip fracture in the elderly multidisciplinary rehabilitation (FEMuR) feasibility study: testing the use of routinely collected data for future health economic evaluations

Background: Health economic evaluations rely on the accurate measurement of health service resource use in order to calculate costs. These are usually measured with patient completed questionnaires using instruments such as the Client Service Receipt Inventory (CSRI). These rely on participants' recall and can be burdensome to complete. Health service activity data are routinely captured by electronic databases.The aim was to test methods for obtaining these data and compare with those data collected using the CSRI, within a feasibility study of an enhanced rehabilitation intervention following hip fracture (Fracture in the Elderly Multidisciplinary Rehabilitation: FEMuR). Methods: Primary care activity including prescribing data was obtained from the Secure Anonymised Information Linkage (SAIL) Databank and secondary care activity (Emergency Department attendances, out-patient visits and in-patient days) directly from Betsi Cadwaladr University Health Board (BCUHB), North Wales, UK. These data were compared with patient responses from the CSRI using descriptive statistics and the intraclass correlation coefficient (ICC). Results: It was possible to compare health service resource use data for 49 out of 61 participants in the FEMuR study. For emergency department (ED) attendances, records matched in 23 (47%) cases, 21 (43%) over-reported on electronic records compared with CSRI and five participants (10%) under-reported, with an overall ICC of 0.42. For out-patient episodes, records matched in only six cases, 28 participants over-reported on electronic records compared with CSRI and 15 (12%) under-reported, with an overall ICC of only 0.27. For in-patient days, records matched exactly in only five cases (10%), but if an error margin of 7 days was allowed, then agreement rose to 39 (66%) cases, and the overall ICC for all data was 0.88.It was only possible to compare prescribing data for 12 participants. For prescribing data, the SAIL data reported 117 out of 118 items (99%) and the CSRI only 89 (79%) items. Conclusions: The use of routinely collected data has the potential to improve the efficiency of trials and other studies. Although the methodology to make the data available has been demonstrated, the data obtained was incomplete and the validity of using this method remains to be demonstrated. Trial registration: Trial registration: ISRCTN22464643 Registered 21 July 2014

Effectiveness and micro-costing of the KiVa school-based bullying prevention programme in Wales: study protocol for a pragmatic definitive parallel group cluster randomised controlled trial

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Bullying refers to verbal, physical or psychological aggression repeated over time that is intended to cause harm or distress to the victims who are unable to defend themselves. It is a key public health priority owing to its widespread prevalence in schools and harmful short- and long-term effects on victims' well-being. There is a need to strengthen the evidence base by testing innovative approaches to preventing bullying. KiVa is a school-based bullying prevention programme with universal and indicated elements and an emphasis on changing bystander behaviour. It achieved promising results in a large trial in Finland, and now requires testing in other countries. This paper describes the protocol for a cluster randomised controlled trial (RCT) of KiVa in Wales. METHODS/DESIGN: The study uses a two-arm waitlist control pragmatic definitive parallel group cluster RCT design with an embedded process evaluation and calculation of unit cost. Participating schools will be randomised a using a 1:1 ratio to KiVa plus usual provision (intervention group) or usual provision only (control group). The trial has one primary outcome, child self-reported victimisation from bullying, dichotomised as 'victimised' (bullied at least twice a month in the last couple of months) versus 'not victimised'. Secondary outcomes are: bullying perpetration; aspects of child social and emotional well-being (including emotional problems, conduct, peer relations, prosocial behaviour); and school attendance. Follow-up is at 12 months post-baseline. Implementation fidelity is measured through teacher-completed lesson records and independent school-wide observation. A micro-costing analysis will determine the costs of implementing KiVa, including recurrent and non-recurrent unit costs. Factors related to the scalability of the programme will be examined in interviews with head teachers and focus groups with key stakeholders in the implementation of school-based bullying interventions. DISCUSSION: The results from this trial will provide evidence on whether the KiVa programme is transportable from Finland to Wales in terms of effectiveness and implementation. It will provide information about the costs of delivery and generate insights into factors related to the scalability of the programme. TRIAL REGISTRATION: Current Controlled Trials ISRCTN23999021 Date 10-6-13.BIG Lottery Wales (REF: B/l/1/010430196) is funding the costs of the trial, including recruitment conferences, provision of programme resources for schools, translation of resources into Welsh, support and feedback sessions, and central organisational meetings. The design, management, statistical analysis and dissemination of the trial are fully independent of the BIG Lottery and KiVa Finland. The programme is delivered by teachers and other school staff during school hours and no supply costs are provided to schools for staff training