Role of Self-Interaction Effects in the Geometry Optimization of Small Metal Clusters

By combining the Self-Interaction Correction (SIC) with pseudopotential perturbation theory, the role of self-interaction errors inherent to the Local Density Approximation (LDA) to Density Functional Theory is estimated in the determination of ground state and low energy isomeric structures of small metallic clusters. Its application to neutral sodium clusters with 8 and 20 atoms shows that the SIC provides sizeable effects in Na_8, leading to a different ordering of the low lying isomeric states compared with ab-initio LDA predictions, whereas for Na_20, the SIC effects are less pronounced, such that a quantitative agreement is achieved between the present method and ab-initio LDA calculations.Comment: RevTeX, 4 pages, 1 figure available from [email protected]

Mixing in thermally stratified nonlinear spin-up with sources and sinks

Stratified spin-up experiments in enclosed cylinders have reported the presence of small pockets of well-mixed fluids but quantitative measurements of the mixedness of the fluid has been lacking. Previous numerical simulations have not addressed these measurements. Here we present numerical simulations that address how the combined effect of spin-up and thermal boundary conditions enhances or hinders mixing of a fluid in a cylinder. Measurements of efficiency of mixing are based on the variance of temperature and explained in terms of the potential energy available. The numerical simulations of the Navier--Stokes equations for the problem with different sets of thermal boundary conditions at the horizontal walls helped shed some light on the physical mechanisms of mixing, for which a clear explanation was lacking.Comment: Submitted to Physics of Fluids, 9 figure

Librarians use of Web 2.0 in UK Medical Schools: Outcomes of a national survey

Using the results of an Email survey, this paper reviews the use of Web 2.0 technologies by librarians working in UK Medical Schools. Web 2.0 has been hailed as an innovation for facilitation of two way communication on the net, and it is, therefore, timely to measure how effectively librarians are capturing this opportunity for increased student engagement. The social nature of Web 2.0 can be particularly appropriate for undergraduate medical students who fit their studies around the unsocial hours and geographical isolation of clinical placements. This paper will investigate library use of blogs, Facebook, and Twitter. Consideration will also be given as to whether they facilitate a more collabroative library service or if they leave undergraduate medical students swamped with yet more information to manage

Lorentz invariance for mixed neutrinos

We show that a proper field theoretical treatment of mixed (Dirac) neutrinos leads to non-trivial dispersion relations for the flavor states. We analyze such a situation in the framework of the non-linear relativity schemes recently proposed by Magueijo and Smolin. We finally examine the experimental implications of our theoretical proposals by considering the spectrum and the end-point of beta decay in tritium.Comment: 8 pages, 4 figures. Presented at 2nd International Workshop DICE2004: From Decoherence and Emergent Classicality to Emergent Quantum Mechanics, Castello di Piombino, Tuscany, Italy, 1-4 Sep 200

Getting people out of unemployment: A spatial perspective across Auckland

Reducing the unemployment rate is an aim of most governing authorities. This paper presents a socio-economic analysis of area-level employment rate changes across Auckland using Census area-level data for the time period 1996 to 2006. Exploratory spatial data analyses suggest the presence of strong spatial patterns in intra-city employment rates changes. Application of seemingly unrelated regressions highlight forces, such as education, that are associated with increases in part time and full time employment relative to being unemployed.Unemployment; Seemingly unrelated regressions; Queen spatial weights