Phase transition in the Ising model on a small-world network with distance-dependent interactions

We study the collective behavior of an Ising system on a small-world network with the interaction $J(r) \propto r^{-\alpha}$, where $r$ represents the Euclidean distance between two nodes. In the case of $\alpha = 0$ corresponding to the uniform interaction, the system is known to possess a phase transition of the mean-field nature, while the system with the short-range interaction $(\alpha\to\infty)$ does not exhibit long-range order at any finite temperature. Monte Carlo simulations are performed at various values of $\alpha$, and the critical value $\alpha_c$ beyond which the long-range order does not emerge is estimated to be zero. Thus concluded is the absence of a phase transition in the system with the algebraically decaying interaction $r^{-\alpha}$ for any nonzero positive value of $\alpha$

Visual cue training to improve walking and turning after stroke:a study protocol for a multi-centre, single blind randomised pilot trial

Visual information comprises one of the most salient sources of information used to control walking and the dependence on vision to maintain dynamic stability increases following a stroke. We hypothesize, therefore, that rehabilitation efforts incorporating visual cues may be effective in triggering recovery and adaptability of gait following stroke. This feasibility trial aims to estimate probable recruitment rate, effect size, treatment adherence and response to gait training with visual cues in contrast to conventional overground walking practice following stroke.Methods/design: A 3-arm, parallel group, multi-centre, single blind, randomised control feasibility trial will compare overground visual cue training (O-VCT), treadmill visual cue training (T-VCT), and usual care (UC). Participants (n = 60) will be randomly assigned to one of three treatments by a central randomisation centre using computer generated tables to allocate treatment groups. The research assessor will remain blind to allocation. Treatment, delivered by physiotherapists, will be twice weekly for 8 weeks at participating outpatient hospital sites for the O-VCT or UC and in a University setting for T-VCT participants.Individuals with gait impairment due to stroke, with restricted community ambulation (gait spee

Home-based reach-to-grasp training for people after stroke: study protocol for a feasibility randomized controlled trial

BackgroundThis feasibility study is intended to assess the acceptability of home-based task-specific reach-to-grasp (RTG) training for people with stroke, and to gather data to inform recruitment, retention, and sample size for a definitive randomized controlled trial. Methods/designThis is to be a randomized controlled feasibility trial recruiting 50 individuals with upper-limb motor impairment after stroke. Participants will be recruited after discharge from hospital and up to 12 months post-stroke from hospital stroke services and community therapy-provider services. Participants will be assessed at baseline, and then electronically randomized and allocated to group by minimization, based on the time post-stroke and extent of upper-limb impairment. The intervention group will receive 14 training sessions, each 1 hour long, with a physiotherapist over 6 weeks and will be encouraged to practice independently for 1 hour/day to give a total of 56 hours of training time per participant. Participants allocated to the control group will receive arm therapy in accordance with usual care. Participants will be measured at 7 weeks post-randomization, and followed-up at 3 and 6 months post-randomization. Primary outcome measures for assessment of arm function are the Action Research Arm Test (ARAT) and Wolf Motor Function Test (WMFT). Secondary measures are the Motor Activity Log, Stroke Impact Scale, Carer Strain Index, and health and social care resource use. All assessments will be conducted by a trained assessor blinded to treatment allocation. Recruitment, adherence, withdrawals, adverse events (AEs), and completeness of data will be recorded and reported. DiscussionThis study will determine the acceptability of the intervention, the characteristics of the population recruited, recruitment and retention rates, descriptive statistics of outcomes, and incidence of AEs. It will provide the information needed for planning a definitive trial to test home-based RTG training. Trial registrationISRCTN: ISRCTN5671658

A systematic review of research guidelines in Decision-Analytic Modelling

AbstractBackgroundDecision-analytic modeling (DAM) has been increasingly used to aid decision making in health care. The growing use of modeling in economic evaluations has led to increased scrutiny of the methods used.ObjectiveThe objective of this study was to perform a systematic review to identify and critically assess good practice guidelines, with particular emphasis on contemporary developments.MethodsA systematic review of English language articles was undertaken to identify articles presenting guidance for good practice in DAM in the evaluation of health care. The inclusion criteria were articles providing guidance or criteria against which to assess good practice in DAM and studies providing criteria or elements for good practice in some areas of DAM. The review covered the period January 1990 to March 2014 and included the following electronic bibliographic databases: Cochrane Library, Cochrane Methodology Register and Health Technology Assessment, NHS Economic Evaluation Database, MEDLINE, and PubMed (Embase). Additional studies were identified by searching references.ResultsThirty-three articles were included in this review. A practical five-dimension framework was developed that describe the key elements of good research practice that should be considered and reported to increase the credibility of results obtained from DAM in the evaluation of health care.ConclusionsThis study is the first to critically review all available guidelines and statements of good practice in DAM since 2006. The development of good practice guidelines is an ongoing process, and important efforts have been made to identify what is good practice and to keep these guidelines up to date

A Comparison of the Validity and Responsiveness of the EQ-5D-5L and SF-6D for Measuring Health Spillovers: A Study of the Family Impact of Meningitis

The “health spillover” of patient illness on family members is important to capture in economic evaluation. This study compares the construct validity and responsiveness of 2 widely used health-related quality-of-life instruments, the EQ-5D-5L and SF-6D, in capturing health spillover effects for family members with and without an informal care role (carers and noncarers). Construct validity and responsiveness were assessed using data from a 2012 UK survey of the family impact of meningitis-related sequelae. Construct validity was assessed by testing associations between family members’ health status and variables anticipated to be associated with spillover effects (patient health status and informal care). Responsiveness was assessed by testing associations between the longitudinal change in family members’ health status and longitudinal change in patient health and caring hours. Among noncarers, both the EQ-5D-5L and the SF-6D exhibited construct validity with 10 of the 11 associations that were hypothesized being statistically significant on both measures. There was less clear evidence of responsiveness of the measures for noncarers. Among carers, the EQ-5D-5L exhibited greater construct validity, as well as responsiveness, with respect to spillovers from patient health. This was evidenced by the EQ-5D-5L detecting 9 significant associations compared with 4 on the SF-6D. However, the SF-6D exhibited greater construct validity with respect to spillovers generated from informal care provision (5 associations significant compared with 2 on the EQ-5D-5L). Both the EQ-5D-5L and the SF-6D exhibited a degree of validity that could justify their use as measures of health-related quality-of-life spillovers on family members in economic evaluation