Ergodic theory on coded shift spaces

We study ergodic-theoretic properties of coded shift spaces. A coded shift space is defined as a closure of all bi-infinite concatenations of words from a fixed countable generating set. We derive sufficient conditions for the uniqueness of measures of maximal entropy and equilibrium states of H\"{o}lder continuous potentials based on the partition of the coded shift into its sequential set (sequences that are concatenations of generating words) and its residual set (sequences added under the closure). In this case we provide a simple explicit description of the measure of maximal entropy. We also obtain flexibility results for the entropy on the sequential and residual set. Finally, we prove a local structure theorem for intrinsically ergodic coded shift spaces which shows that our results apply to a larger class of coded shift spaces compared to previous works by Climenhaga, Climenhaga and Thompson, and Pavlov.Comment: 43 page

Paediatric glaucoma in Scotland

Background The primary aim was to estimate the incidence of primary and secondary childhood glaucoma in Scotland over a 2-year period. The secondary aim was to gauge the confidence and experience of ophthalmologists in Scotland in managing these patients. Methods A 7 question electronic survey was distributed to all consultant members of the Scottish Paediatric Club and Scottish Glaucoma Club. Respondents were asked to report the number of cases and types of childhood glaucoma they had managed in the last 2 years. Respondents were also asked about experience and confidence in a range of glaucoma procedures, number of patients requiring referral to specialist centres and interest in the development of a centre of excellence in Scotland. Results The survey returned a 56% response rate, reporting 85 new cases of paediatric glaucoma in Scotland over the preceding 2 years. 11 (12.9%) had primary glaucoma and 74 (87.1%) had secondary glaucoma. The most common subtype of secondary glaucoma was uveitic glaucoma (n = 29). None of the respondents declared confidence or experience in trabeculotomy or goniotomy procedures. Eleven children required referral to a specialist unit outside Scotland. 85.7% of respondents felt Scotland would benefit from a specialist unit for paediatric glaucoma. Conclusions This survey reflects an appetite for a specialist service for paediatric glaucoma in Scotland. However, further consideration is needed to determine if there is sufficient patient load to maintain such a service.Publisher PDFPeer reviewe

OIDA: An optimal interval detection algorithm for automatized determination of stimulation patterns for FES-Cycling in individuals with SCI

International audienceBackground: FES-Cycling is an exciting recreational activity, which allows certain individuals after spinal cord injury or stroke to exercise their paralyzed muscles. The key for a successful application is to activate the right muscles at the right time. Methods: While a stimulation pattern is usually determined empirically, we propose an approach using the torque feedback provided by a commercially available crank power-meter installed on a standard trike modified for FES-Cycling. By analysing the difference between active (with stimulation) and passive (without stimulation) torques along a full pedalling cycle, it is possible to differentiate between contributing and resisting phases for a particular muscle group. In this article we present an algorithm for the detection of optimal stimulation intervals and demonstrate its functionality, bilaterally for the quadriceps and hamstring muscles, in one subject with complete SCI on a home trainer. Stimulation patterns were automatically determined for two sensor input modalities: the crank-angle and a normalized thigh-angle (i.e. cycling phase, measured via inertial measurement units). In contrast to previous studies detecting automatic stimulation intervals on motorised ergo-cycles, our approach does not rely on a constant angular velocity provided by a motor, thus being applicable to the domain of mobile FES-Cycling. Results: The algorithm was successfully able to identify stimulation intervals, individually for the subject's left and right quadriceps and hamstring muscles. Smooth cycling was achieved without further adaptation, for both input signals (i.e. crank-angle and normalized thigh-angle). Conclusion: The automatic determination of stimulation patterns, on basis of the positive net-torque generated during electrical stimulation, can help to reduce the duration of the initial fitting phase and to improve the quality of pedalling during a FES-Cycling session. In contrast to previous works, the presented algorithm does not rely on a constant angular velocity and thus can be effectively implemented into mobile FES-Cycling systems. As each muscle or muscle group is assessed individually, our algorithm can be used to evaluate the efficiency of novel electrode configurations and thus could promote increased performances during FES-Cycling