Social isolation predicts frequent attendance in primary care

Background. Frequent attenders in primary care have complex physical and mental healthcare needs as well as low satisfaction with their healthcare. Interventions targeting mental health or psychoeducation have not been effective in reducing attendance. Here, we test the proposition that both frequent attendance and poor health are partly explained by unmet social needs (i.e., limited social group support networks). Methods. Study 1 (N=1752) was a large cross-sectional community sample of primary care attenders in Scotland. Study 2 (N = 79) was a longitudinal study of a group of young people undergoing a life transition (moving countries and commencing university) that increased their risk of frequent attendance. Study 3 (N=46) was a pre-post intervention study examining whether disadvantaged adults who joined a social group subsequently had reduced frequency of primary care attendance. Results. All three studies found that low social group connectedness was associated with a higher frequency of primary care attendance. This was not attributable to poorer health among those who were socially isolated. In Study 3, joining a social group led to reduced primary care attendance to the extent that participants experienced a (subjective) increase in their social group connectedness. Conclusions. Unmet social needs among frequent attenders warrant closer consideration. Interventions that target social group connectedness show promise for reducing overutilization of primary care services

A Parallel and Distributed Analysis Pipeline for Performance Tree Evaluation

Performance Trees are a unifying framework for the specification of performance queries involving measures and requirements. This paper describes an evaluation environment for Performance Trees comprising a client-side Performance Query Editor, incorporated as a module of the PIPE2 Petri net tool, and a cluster-based server-side evaluation engine. The latter combines the capabilities of a number of parallel and distributed analysis tools

Renormalons in the effective potential of the vectorial (φ⃗2)2(\vec{\varphi}^{2})^{2} model

We study the properties of ultraviolet renormalons in the vectorial $(\vec{\phi}^{2})^{2}$ model. This is achieved by studying the effective potential of the theory at next to leading order of the $1/N$ expansion, the appearence ofthe renormalons in the perturbative series and their relation to the imaginary part of the potential. We also consider the mechanism of renormalon cancellation by `irrelevant" higher dimensional operators.Comment: 20 pages, Latex, 3 Postscript figure

Distributed Response Time Analysis of GSPN Models with MapReduce

widely used in the performance analysis of computer and communications systems. Response time densities and quantiles are often key outputs of such analysis. These can be extracted from a GSPN’s underlying semi-Markov process using a method based on numerical Laplace transform inversion. This method typically requires the solution of thousands of systems of complex linear equations, each of rank n, where n is the number of states in the model. For large models substantial processing power is needed and the computation must therefore be distributed. This paper describes the implementation of a Response Time Analysis module for the Platform Independent Petri net Editor (PIPE2) which interfaces with Hadoop, an open source implementation of Google’s MapReduce distributed programming environment, to provide distributed calculation of response time densities in GSPN models. The software is validated with analytically calculated results as well as simulated ones for larger models. Excellent scalability is shown. I

Combining high conductivity with complete optical transparency: A band-structure approach

A comparison of the structural, optical and electronic properties of the recently discovered transparent conducting oxide (TCO), nanoporous Ca12Al14O33, with those of the conventional TCO's (such as Sc-doped CdO) indicates that this material belongs conceptually to a new class of transparent conductors. For this class of materials, we formulate criteria for the successful combination of high electrical conductivity with complete transparency in the visible range. Our analysis suggests that this set of requirements can be met for a group of novel materials called electrides.Comment: 3 pages, 3 figures, submitted for publicatio

On the Aggregation of Inertial Particles in Random Flows

We describe a criterion for particles suspended in a randomly moving fluid to aggregate. Aggregation occurs when the expectation value of a random variable is negative. This random variable evolves under a stochastic differential equation. We analyse this equation in detail in the limit where the correlation time of the velocity field of the fluid is very short, such that the stochastic differential equation is a Langevin equation.Comment: 16 pages, 2 figure

Surface effects on nanowire transport: numerical investigation using the Boltzmann equation

A direct numerical solution of the steady-state Boltzmann equation in a cylindrical geometry is reported. Finite-size effects are investigated in large semiconducting nanowires using the relaxation-time approximation. A nanowire is modelled as a combination of an interior with local transport parameters identical to those in the bulk, and a finite surface region across whose width the carrier density decays radially to zero. The roughness of the surface is incorporated by using lower relaxation-times there than in the interior. An argument supported by our numerical results challenges a commonly used zero-width parametrization of the surface layer. In the non-degenerate limit, appropriate for moderately doped semiconductors, a finite surface width model does produce a positive longitudinal magneto-conductance, in agreement with existing theory. However, the effect is seen to be quite small (a few per cent) for realistic values of the wire parameters even at the highest practical magnetic fields. Physical insights emerging from the results are discussed.Comment: 15 pages, 7 figure