Superposition-Enhanced Estimation of Optimal Temperature Spacings for Parallel Tempering Simulations.

Effective parallel tempering simulations rely crucially on a properly chosen sequence of temperatures. While it is desirable to achieve a uniform exchange acceptance rate across neighboring replicas, finding a set of temperatures that achieves this end is often a difficult task, in particular for systems undergoing phase transitions. Here we present a method for determination of optimal replica spacings, which is based upon knowledge of local minima in the potential energy landscape. Working within the harmonic superposition approximation, we derive an analytic expression for the parallel tempering acceptance rate as a function of the replica temperatures. For a particular system and a given database of minima, we show how this expression can be used to determine optimal temperatures that achieve a desired uniform acceptance rate. We test our strategy for two atomic clusters that exhibit broken ergodicity, demonstrating that our method achieves uniform acceptance as well as significant efficiency gains.This project was funded by EPSRC Grant EP/I001352/1 and the ERC

Stretching in a model of a turbulent flow

Using a multi-scaled, chaotic flow known as the KS model of turbulence, we investigate the dependence of Lyapunov exponents on various characteristics of the flow. We show that the KS model yields a power law relation between the Reynolds number and the maximum Lyapunov exponent, which is similar to that for a turbulent flow with the same energy spectrum. Our results show that the Lyapunov exponents are sensitive to the advection of small eddies by large eddies, which can be explained by considering the Lagrangian correlation time of the smallest scales. We also relate the number of stagnation points within a flow to the maximum Lyapunov exponent, and suggest a linear dependence between the two characteristics.Comment: 7 pages, 10 figure

Genetic variation in two conserved local Romanian pig breeds using type 1 DNA markers

Analysis of the genetic variation of an endangered population is an important component for the success of conservation. Animals from two local Romanian pig breeds, the Mangalitsa and Bazna, were analysed for variation at a number of genetic loci using PCR-based DNA tests. Polymorphism was assessed at loci which 1) are known to cause phenotypic variation, 2) are potentially involved in trait differences or 3) are putative candidate genes. The traits considered are disease resistance, growth, coat colour, meat quality and prolificacy. Even though the populations are small and the markers are limited to specific genes, we found significant differences in five of the ten characterised loci. In some cases the observed allele frequencies were interesting in relation to gene function and the phenotype of the breed. These breeds are part of a conservation programme in Romania and marker information may be useful in preserving a representative gene pool in the populations. The use of polymorphisms in type 1 (gene) markers may be a useful complement to analysis based on anonymous markers

Novel low energy hydrogen–deuterium isotope breakthrough separation using a trapdoor zeolite

AbstractCs-chabazite, a type of zeolite with caesium counter-cations, possesses interesting gas separation properties due to a highly selective molecular “trapdoor” effect. Herein the use of this material for H2/D2 isotope separation is demonstrated. Isotope separation was achieved using breakthrough separation with a single pass through a packed bed at moderate temperatures (293K) and pressures (0.17MPa) when one species was in a sufficiently low concentration. The breakthrough separation curves were successfully modelled using the Thomas kinetic breakthrough model and the Yoon and Nelson kinetic breakthrough model, where working transferable kinetic rate constants were developed. Use of this material for hydrogen isotope separation would significantly lower the total energy demand compared with current hydrogen isotope separation techniques such as cryogenic distillation and is applicable to separating out low concentrations of D2 (0.0156%) present in standard grade H2

Simulated learning in a mock ward setting: a tool for developing clinical knowledge, improving patient safety and inspiring future hospital pharmacists.

Title: Simulated learning in a mock ward setting: a tool for developing clinical knowledge, improving patient safety and inspiring future hospital pharmacists. Authors: Sturrock A, Wales J, Hardisty J, Statham L Institution: University of Sunderland Background: Traditional didactic teaching and learning methods can provide fundamental knowledge, but do not develop the clinical skills that are required to apply knowledge to complex, patent focused scenarios. Simulated learning sessions have been successfully implemented as a tool for developing the required skills in a safe and realistic setting (Aggarwal et al 2010). Recent investment at the University provided the creation of four purpose built mock wards each replicating the clinical environment of an acute hospital setting. Aim: To explore the perceptions of pharmacy students towards simulated learning as a tool for developing clinical knowledge and stimulating an interest in hospital pharmacy. Method: A series of simulated learning sessions were delivered to Stage 3 pharmacy students; students participated in mock ward rounds and sessions utilising SimMan® 3G technology. A particular focus was directed towards patient safety and the safe prescribing of high risk drugs, such as insulin and opioid analgesics. A qualitative evaluation was performed, consisting of a focus group with a representative sample of 8 students. Results: Students perceived simulated learning to have improved their retention of knowledge and their ability to apply concepts to the care of patients. Students reported that the sessions required them to adapt to unfamiliar and challenging situations; a skill which will be beneficial for them in practice. Following the sessions, a number of students expressed a desire to pursue a career in hospital pharmacy. One of the key observations made was the high level of engagement in the simulated ward sessions compared to traditional classroom activities; the interactive nature of the sessions facilitated a higher level of discussion around key topics. Students highlighted the potential benefits of increasing the number of interactive resources in the sessions; further utilisation of SimMan® 3G and additional facilitators, such as nursing staff, medics and patients could enhance the realism of the simulation. Conclusion: Students perceive that simulated learning can enhance knowledge retention and develop the ability to adapt to challenging situations. Simulated ward activities can be utilised to develop aspirations towards a career in hospital pharmacy