Further evidence of the absence of Replica Symmetry Breaking in Random Bond Potts Models

In this short note, we present supporting evidence for the replica symmetric approach to the random bond q-state Potts models. The evidence is statistically strong enough to reject the applicability of the Parisi replica symmetry breaking scheme to this class of models. The test we use is a generalization of one formerly proposed by Dotsenko et al. and consists in measuring scaling laws of disordered-averaged moments of the spin-spin correlation functions. Numerical results, obtained via Monte Carlo simulations for several values of q, are shown to be in fair agreement with the replica symmetric values computed by using perturbative CFT for the second and third moments of the q=3 model. RSB effects, which should increase in strength with moment, are unobserved.Comment: 7 pages, some minor modifications (mainly misprints). To Appear in Europhysics Letter

Applying a Multidimensional Strategy to Mitigate Lateral Violence in a Small Rural Community Hospital in Western New York

Providing registered nurses with education and strategies to mitigate lateral violence is an evidenced-based method for creating a culture of civility. A descriptive pilot study with registered nurses was conducted on two medical/surgical units at a small rural community hospital. Strategies included a review of organizational policies, a one-day educational retreat for unit managers and registered nurse champions, and an online educational toolkit on lateral violence for the staff nurses on the pilot units

Population extremal optimisation for discrete multi-objective optimisation problems

The power to solve intractable optimisation problems is often found through population based evolutionary methods. These include, but are not limited to, genetic algorithms, particle swarm optimisation, differential evolution and ant colony optimisation. While showing much promise as an effective optimiser, extremal optimisation uses only a single solution in its canonical form – and there are no standard population mechanics. In this paper, two population models for extremal optimisation are proposed and applied to a multi-objective version of the generalised assignment problem. These models use novel intervention/interaction strategies as well as collective memory in order to allow individual population members to work together. Additionally, a general non-dominated local search algorithm is developed and tested. Overall, the results show that improved attainment surfaces can be produced using population based interactions over not using them. The new EO approach is also shown to be highly competitive with an implementation of NSGA-II.No Full Tex

A parallel implementation of ant colony optimization

Ant Colony Optimization is a relatively new class of meta-heuristic search techniques for optimization problems. As it is a population-based technique that examines numerous solution options at each step of the algorithm, there are a variety of parallelization opportunities. In this paper, several parallel decomposition strategies are examined. These techniques are applied to a specific problem, namely the travelling salesman problem, with encouraging speedup and efficiency results.Full Tex

RIOJA (Repository Interface to Overlaid Journal Archives) project: final report

RIOJA (Repository Interface to Overlaid Journal Archives) was a 18-month partnership between UCL (University College London), Imperial College London, and the Universities Glasgow, Cambridge and Cornell. The project was funded by the JISC (Joint Information Systems Committee, UK). The project team worked with the Astrophysics community investigate aspects of overlay journals. For the purposes of the project, an overlay was defined as a quality-assured journal whose content is deposited to and resides more open access repositories. The project had both technical aims and supporting, non-technical aims. The primary technical deliverable from the project was a toolkit for the creation and maintenance overlay journals. The toolkit supports the exchange of data between a repository and piece of journal software. It supports functions such as author validation, metadata extraction from the source repository, and submission tracking. The toolkit is platform-neutral and could, in theory, be employed by any journal using content from any number repositories, in any discipline. The project also implemented a demonstrator overlay applying the RIOJA toolkit to the arXiv subject repository, and a demonstrator implementation of the RIOJA tool for GNU EPrints. Aside from creating the demonstrator and its underlying tools, the project aimed to acceptibility and feasibility of the overlay model. First, a large-scale survey of the Astrophysics community was undertaken. The survey collected data about research publishing practices within this community, and probed its reaction to the principle publishing. Second, the views of editors and publishers in this discipline were sought through interviews. These views were added to findings from the literature and summarised in a more general report on issues around the sustainability of an overlay journal

Spreading Speed, Traveling Waves, and Minimal Domain Size in\ud Impulsive Reaction-diffusion Models

How growth, mortality, and dispersal in a species affect the species’ spread and persistence constitutes a central problem in spatial ecology. We propose impulsive reaction-diffusion equation models for species with distinct reproductive and dispersal stages. These models can describe a seasonal birth pulse plus nonlinear mortality and dispersal throughout the year. Alternatively they can describe seasonal harvesting, plus nonlinear birth and mortality as well as dispersal throughout the year. The population dynamics in the seasonal pulse is described by a discrete map that gives the density of the populationat the end stage as a possibly nonmonotone function of the density of the population at the beginning of the stage. The dynamics in the dispersal stage is governed by a nonlinear reaction-diffusion equation in a bounded or unbounded domain. We develop a spatially explicit theoretical framework that links species vital rates (mortality or fecundity) and dispersal characteristics with species’ spreading speeds, traveling wave speeds, as well as and minimal domain size for species persistence. We provide an explicit formula for the spreading speed in terms of model parameters, and show that the spreading speed can be characterized as the slowest speed of a class of traveling wave solutions. We also determine an explicit formula for the minimal domain size using model parameters. Our results show how the diffusion coefficient, and the combination of discrete- and continuous-time growth and mortality determine the spread and persistence dynamics of the population in a wide variety of ecological scenarios. Numerical simulations are presented to demonstrate the theoretical results