3,902 research outputs found

    Tunneling-percolation origin of nonuniversality: theory and experiments

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    A vast class of disordered conducting-insulating compounds close to the percolation threshold is characterized by nonuniversal values of transport critical exponent t, in disagreement with the standard theory of percolation which predicts t = 2.0 for all three dimensional systems. Various models have been proposed in order to explain the origin of such universality breakdown. Among them, the tunneling-percolation model calls into play tunneling processes between conducting particles which, under some general circumstances, could lead to transport exponents dependent of the mean tunneling distance a. The validity of such theory could be tested by changing the parameter a by means of an applied mechanical strain. We have applied this idea to universal and nonuniversal RuO2-glass composites. We show that when t > 2 the measured piezoresistive response \Gamma, i. e., the relative change of resistivity under applied strain, diverges logarithmically at the percolation threshold, while for t = 2, \Gamma does not show an appreciable dependence upon the RuO2 volume fraction. These results are consistent with a mean tunneling dependence of the nonuniversal transport exponent as predicted by the tunneling-percolation model. The experimental results are compared with analytical and numerical calculations on a random-resistor network model of tunneling-percolation.Comment: 13 pages, 12 figure

    Development of a behaviour change intervention: a case study on the practical application of theory

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    BACKGROUND: Use of theory in implementation of complex interventions is widely recommended. A complex trial intervention, to enhance self-management support for people with osteoarthritis (OA) in primary care, needed to be implemented in the Managing Osteoarthritis in Consultations (MOSAICS) trial. One component of the trial intervention was delivery by general practitioners (GPs) of an enhanced consultation for patients with OA. The aim of our case study is to describe the systematic selection and use of theory to develop a behaviour change intervention to implement GP delivery of the enhanced consultation. METHODS: The development of the behaviour change intervention was guided by four theoretical models/frameworks: i) an implementation of change model to guide overall approach, ii) the Theoretical Domains Framework (TDF) to identify relevant determinants of change, iii) a model for the selection of behaviour change techniques to address identified determinants of behaviour change, and iv) the principles of adult learning. Methods and measures to evaluate impact of the behaviour change intervention were identified. RESULTS: The behaviour change intervention presented the GPs with a well-defined proposal for change; addressed seven of the TDF domains (e.g., knowledge, skills, motivation and goals); incorporated ten behaviour change techniques (e.g., information provision, skills rehearsal, persuasive communication); and was delivered in workshops that valued the expertise and professional values of GPs. The workshops used a mixture of interactive and didactic sessions, were facilitated by opinion leaders, and utilised 'context-bound communication skills training.' Methods and measures selected to evaluate the behaviour change intervention included: appraisal of satisfaction with workshops, GP report of intention to practise and an assessment of video-recorded consultations of GPs with patients with OA. CONCLUSIONS: A stepped approach to the development of a behaviour change intervention, with the utilisation of theoretical frameworks to identify determinants of change matched with behaviour change techniques, has enabled a systematic and theory-driven development of an intervention designed to enhance consultations by GPs for patients with OA. The success of the behaviour change intervention in practice will be evaluated in the context of the MOSAICS trial as a whole, and will inform understanding of practice level and patient outcomes in the trial

    Exercise for lower limb osteoarthritis : systematic review incorporating trial sequential analysis and network meta-analysis

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    Objective: To determine whether there is sufficient evidence to conclude that exercise interventions are more effective than no exercise control and to compare the effectiveness of different exercise interventions in relieving pain and improving function in patients with lower limb osteoarthritis. Data sources: Nine electronic databases searched from inception to March 2012. Study selection: Randomised controlled trials comparing exercise interventions with each other or with no exercise control for adults with knee or hip osteoarthritis. Data extraction: Two reviewers evaluated eligibility and methodological quality. Main outcomes extracted were pain intensity and limitation of function. Trial sequential analysis was used to investigate reliability and conclusiveness of available evidence for exercise interventions. Bayesian network meta-analysis was used to combine both direct (within trial) and indirect (between trial) evidence on treatment effectiveness. Results: 60 trials (44 knee, two hip, 14 mixed) covering 12 exercise interventions and with 8218 patients met inclusion criteria. Sequential analysis showed that as of 2002 sufficient evidence had been accrued to show significant benefit of exercise interventions over no exercise control. For pain relief, strengthening, flexibility plus strengthening, flexibility plus strengthening plus aerobic, aquatic strengthening, and aquatic strengthening plus flexibility, exercises were significantly more effective than no exercise control. A combined intervention of strengthening, flexibility, and aerobic exercise was also significantly more effective than no exercise control for improving limitation in function (standardised mean difference −0.63, 95% credible interval −1.16 to −0.10). Conclusions: As of 2002 sufficient evidence had accumulated to show significant benefit of exercise over no exercise in patients with osteoarthritis, and further trials are unlikely to overturn this result. An approach combining exercises to increase strength, flexibility, and aerobic capacity is likely to be most effective in the management of lower limb osteoarthritis. The evidence is largely from trials in patients with knee osteoarthritis

    A nurse-led clinic for patients consulting with osteoarthritis in general practice: development and impact of training in a cluster randomised controlled trial

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    Background: Despite a lack of service provision for people with osteoarthritis (OA), each year 1 in 5 of the general population consults a GP about a musculoskeletal condition such as OA. Consequently this may provide an opportunity for practice nurses to take an active role in helping patients manage their condition. A nurse led clinic for supporting patients with OA was developed for the MOSAICS study investigating how to implement the NICE 2014 OA Guideline core recommendations. This paper has two main objectives, firstly to provide an overview of the nurse-led OA clinic, and secondly to describe the development, key learning objectives, content and impact of the training to support its delivery. Methods: A training programme was developed and delivered to provide practice nurses with the knowledge and skill set needed to run the nurse-led OA clinic. The impact of the training programme on knowledge, confidence and OA management was evaluated using case report forms and pre and post training questionnaires. Results: The pre-training questionnaire identified a gap between what practice nurses feel they can do and what they should be doing in line with NICE OA guidelines. Evaluation of the training suggests that it enabled practice nurses to feel more knowledgeable and confident in supporting patients to manage their OA and this was reflected in the clinical management patients received in the nurse-led OA clinics. Conclusions: A significant gap between what is recommended and what practice nurses feel they can currently provide in terms of OA management was evident. The development of a nurse training programme goes some way to develop a system in primary care for delivering the core recommendations by NICE

    Uptake of the NICE osteoarthritis guidelines in primary care: a survey of older adults with joint pain

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    Background Osteoarthritis (OA) is a leading cause of pain and disability. NICE OA guidelines (2008) recommend that patients with OA should be offered core treatments in primary care. Assessments of OA management have identified a need to improve primary care of people with OA, as recorded use of interventions concordant with the NICE guidelines is suboptimal in primary care. The aim of this study was to i) describe the patient-reported uptake of non-pharmacological and pharmacological treatments recommended in the NICE OA guidelines in older adults with a self-reported consultation for joint pain and ii) determine whether patient characteristics or OA diagnosis impact uptake. Methods A cross-sectional survey mailed to adults aged ≥45 years (n = 28,443) from eight general practices in the UK as part of the MOSAICS study. Respondents who reported the presence of joint pain, a consultation in the previous 12 months for joint pain, and gave consent to medical record review formed the sample for this study. Results Four thousand fifty-nine respondents were included in the analysis (mean age 65.6 years (SD 11.2), 2300 (56.7%) females). 502 (12.4%) received an OA diagnosis in the previous 12 months. More participants reported using pharmacological treatments (e.g. paracetamol (31.3%), opioids (40.4%)) than non-pharmacological treatments (e.g. exercise (3.8%)). Those with an OA diagnosis were more likely to use written information (OR 1.57; 95% CI 1.26,1.96), paracetamol (OR 1.30; 95% CI 1.05,1.62) and topical NSAIDs (OR 1.30; 95% CI 1.04,1.62) than those with a joint pain code. People aged ≥75 years were less likely to use written information (OR 0.56; 95% CI 0.40,0.79) and exercise (OR 0.37; 95% CI 0.25,0.55) and more likely to use paracetamol (OR 1.91; 95% CI 1.38,2.65) than those aged < 75 years. Conclusion The cross-sectional population survey was conducted to examine the uptake of the treatments that are recommended in the NICE OA guidelines in older adults with a self-reported consultation for joint pain and to determine whether patient characteristics or OA diagnosis impact uptake. Non-pharmacological treatment was suboptimal compared to pharmacological treatment. Implementation of NICE guidelines needs to examine why non-pharmacological treatments, such as exercise, remain under-used especially among older people

    Effect of a model consultation informed by guideline on recorded quality of care of osteoarthritis (MOSAICS): a cluster randomised controlled trial in primary care

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    Objective To determine the effect of a model osteoarthritis (OA) consultation (MOAC) informed by National Institute for Health and Care Excellence (NICE) recommendations compared with usual care on recorded quality of care of clinical OA in general practice. Design Two-arm cluster randomised controlled trial. Setting Eight general practices in Cheshire, Shropshire, or Staffordshire UK. Participants General practitioners and nurses with patients consulting with clinical OA. Intervention Following six-month baseline period practices were randomised to intervention (n = 4) or usual care (n = 4). Intervention practices delivered MOAC (enhanced initial GP consultation, nurse-led clinic, OA guidebook) to patients aged ≥45 years consulting with clinical OA. An electronic (e-)template for consultations was used in all practices to record OA quality care indicators. Outcomes Quality of OA care over six months recorded in the medical record. Results 1851 patients consulted in baseline period (1015 intervention; 836 control); 1960 consulted following randomisation (1118 intervention; 842 control). At baseline wide variations in quality of care were noted. Post-randomisation increases were found for written advice on OA (4–28%), exercise (4–22%) and weight loss (1–15%) in intervention practices but not controls (1–3%). Intervention practices were more likely to refer to physiotherapy (10% vs 2%, odds ratio 5.30; 95% CI 2.11, 13.34), and prescribe paracetamol (22% vs 14%, 1.74; 95% CI 1.27, 2.38). Conclusions The intervention did not improve all aspects of care but increased core NICE recommendations of written advice on OA, exercise and weight management. There remains a need to reduce variation and uniformly enhance improvement in recorded OA care

    The clinical and cost effectiveness of steroid injection compared with night splints for carpal tunnel syndrome: the INSTINCTS randomised clinical trial study protocol.

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    BACKGROUND: Patients diagnosed with idiopathic mild to moderate carpal tunnel syndrome (CTS) are usually managed in primary care and commonly treated with night splints and/or corticosteroid injection. The comparative effectiveness of these interventions has not been reliably established nor investigated in the medium and long term. The primary objective of this trial is to investigate whether corticosteroid injection is effective in reducing symptoms and improving hand function in mild to moderate CTS over 6 weeks when compared with night splints. Secondary objectives are to determine specified comparative clinical outcomes and cost effectiveness of corticosteroid injection over 6 and 24 months. METHOD/DESIGN: A multicentre, randomised, parallel group, clinical pragmatic trial will recruit 240 adults aged ≥18 years with mild to moderate CTS from GP Practices and Primary-Secondary Care Musculoskeletal Interface Clinics. Diagnosis will be by standardised clinical assessment. Participants will be randomised on an equal basis to receive either one injection of 20 mg Depo-Medrone or a night splint to be worn for 6 weeks. The primary outcome is the overall score of the Boston Carpal Tunnel Questionnaire (BCTQ) at 6 weeks. Secondary outcomes are the BCTQ symptom severity and function status subscales, symptom intensity, interrupted sleep, adherence to splinting, perceived benefit and satisfaction with treatment, work absence and reduction in work performance, EQ-5D-5L, referral to surgery and health utilisation costs. Participants will be assessed at baseline and followed up at 6 weeks, 6, 12 and 24 months. The primary analysis will use an intention to treat (ITT) approach and multiple imputation for missing data. The sample size was calculated to detect a 15 % greater improvement in the BTCQ overall score in the injection group compared to night-splinting at approximately 90 % power, 5 % two-tailed significance and allows for 15 % loss to follow-up. DISCUSSION: The trial makes an important contribution to the evidence base available to support effective conservative management of CTS in primary care. No previous trials have directly compared these treatments for CTS in primary care populations, reported on clinical effectiveness at more than 6 months nor compared cost effectiveness of the interventions. TRIAL REGISTRATION: Trial registration: EudraCT 2013-001435-48 (registered 05/06/2013), ClinicalTrials.gov NCT02038452 (registered 16/1/2014), and Current Controlled Trials ISRCTN09392969 (retrospectively registered 01/05/2014)

    Electrostatic considerations affecting the calculated HOMO-LUMO gap in protein molecules.

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    A detailed study of energy differences between the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO gaps) in protein systems and water clusters is presented. Recent work questioning the applicability of Kohn-Sham density-functional theory to proteins and large water clusters (E. Rudberg, J. Phys.: Condens. Mat. 2012, 24, 072202) has demonstrated vanishing HOMO-LUMO gaps for these systems, which is generally attributed to the treatment of exchange in the functional used. The present work shows that the vanishing gap is, in fact, an electrostatic artefact of the method used to prepare the system. Practical solutions for ensuring the gap is maintained when the system size is increased are demonstrated. This work has important implications for the use of large-scale density-functional theory in biomolecular systems, particularly in the simulation of photoemission, optical absorption and electronic transport, all of which depend critically on differences between energies of molecular orbitals.Comment: 13 pages, 4 figure

    The clinical and cost-effectiveness of corticosteroid injection versus night splints for carpal tunnel syndrome (INSTINCTS trial): an open-label, parallel group, randomised controlled trial

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    Background To our knowledge, the comparative effectiveness of commonly used conservative treatments for carpal tunnel syndrome has not been evaluated previously in primary care. We aimed to compare the clinical and cost-effectiveness of night splints with a corticosteroid injection with regards to reducing symptoms and improving hand function in patients with mild or moderate carpal tunnel syndrome. Methods We did this randomised, open-label, pragmatic trial in adults (≥18 years) with mild or moderate carpal tunnel syndrome recruited from 25 primary and community musculoskeletal clinics and services. Patients with a new episode of idiopathic mild or moderate carpal tunnel syndrome of at least 6 weeks' duration were eligible. We randomly assigned (1:1) patients (permutated blocks of two and four by site) with an online web or third party telephone service to receive either a single injection of 20 mg methylprednisolone acetate (from 40 mg/mL) or a night-resting splint to be worn for 6 weeks. Patients and clinicians could not be masked to the intervention. The primary outcome was the overall score of the Boston Carpal Tunnel Questionnaire (BCTQ) at 6 weeks. We used intention-to-treat analysis, with multiple imputation for missing data, which was concealed to treatment group allocation. The trial is registered with the European Clinical Trials Database, number 2013-001435-48, and ClinicalTrial.gov, number NCT02038452. Findings Between April 17, 2014, and Dec 31, 2016, 234 participants were randomly assigned (118 to the night splint group and 116 to the corticosteroid injection group), of whom 212 (91%) completed the BCTQ at 6 weeks. The BCTQ score was significantly better at 6 weeks in the corticosteroid injection group (mean 2·02 [SD 0·81]) than the night splint group (2·29 [0·75]; adjusted mean difference −0·32; 95% CI −0·48 to −0·16; p=0·0001). No adverse events were reported. Interpretation A single corticosteroid injection shows superior clinical effectiveness at 6 weeks compared with night-resting splints, making it the treatment of choice for rapid symptom response in mild or moderate carpal tunnel syndrome presenting in primary care

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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