Finite-connectivity spin-glass phase diagrams and low-density parity check codes

We obtain phase diagrams of regular and irregular finite-connectivity spin glasses. Contact is first established between properties of the phase diagram and the performance of low-density parity check (LDPC) codes within the replica symmetric (RS) ansatz. We then study the location of the dynamical and critical transition points of these systems within the one step replica symmetry breaking theory (RSB), extending similar calculations that have been performed in the past for the Bethe spin-glass problem. We observe that the location of the dynamical transition line does change within the RSB theory, in comparison with the results obtained in the RS case. For LDPC decoding of messages transmitted over the binary erasure channel we find, at zero temperature and rate R=14, an RS critical transition point at pc 0.67 while the critical RSB transition point is located at pc 0.7450±0.0050, to be compared with the corresponding Shannon bound 1-R. For the binary symmetric channel we show that the low temperature reentrant behavior of the dynamical transition line, observed within the RS ansatz, changes its location when the RSB ansatz is employed; the dynamical transition point occurs at higher values of the channel noise. Possible practical implications to improve the performance of the state-of-the-art error correcting codes are discussed. © 2006 The American Physical Society.

The roles of community pharmacists and other pharmacy staff:public perceptions

Introduction: The focus of the community pharmacist’s (CP’s) activities continues to move away from traditional dispensing activities towards the provision of health services. Current functions of CPs cover a combination of roles including prescription matters, counselling and service provision. These expanding roles, along with raised prescription volume, have increased CP workload. Therefore, it has become commonplace to delegate certain activities to other pharmacy staff (PS). This research aimed to examine public perceptions of CPs and other PS functions. Methodology: A self-completion postal questionnaire was sent to a random sample of 9769 members of the general public in England. Participants were asked to indicate which functions they believed CPs and other PS perform. Data were imported into SPSS 22 for analysis. Results: A response rate of 15.7% (n = 1537) was achieved. The roles most commonly attributed to CPs were monitoring prescription appropriateness (90.4%, n = 1390) and counselling patients on prescribed medicines (90.4%, n = 1389). The role most commonly attributed to other PS was sales transactions (92.4%, n = 1420). Similar numbers of responders agreed that the delivery of health services was the role of both CPs and other PS (58.9%, n = 906; 57.0%, n = 876). Conclusion: Despite a move towards more service based practice, the public still primarily associate the CP’s role with activities centred on dispensing. The provision of health services was seen to be equally carried out by CPs and other PS. As the CP’s service-based activities continue to develop, promotional activities may be required to ensure developments in CP functions are recognised by the public