Fast Calculation of the Radiative Opacity of Plasma

Plasma opacity calculations play an important role in solar modelling and many plasma physics and inertial confinement fusion experiments. This thesis is focussed on the fast calculation of opacity from first principles. The existing average atom (AA) opacity code IMP [1] is used alongside experimental data and detailed atomic physics to develop new models; the results show that simple models can give an excellent description of plasma spectra for a large range of conditions. The results are significant for the development of fast opacity codes which necessarily use the AA approach. The application of fast models to very large scale calculations is considered and an efficient approach to these developed; this allows the fast description of experimental data that would not have otherwise been possible [2]. Analysis of this data then allows the accuracy of the IMP model to be further discussed. The atomic model is also considered, and an improved approach implemented. These improvements makes little difference to the description of experiment provided electron exchange is included. The range of applicability of the IMP model is then extended to higher density by adding a fast description of line broadening by electrons. This gives an excellent agreement with both experiment and more advanced opacity codes. The treatment of atomic term structure can represent a significant portion of code runtime. A good compromise between detail and efficiency is the unresolved transition array (UTA) formulation; a consistent theory of UTAs is developed, and various models introduced. The accuracy of these is systematically tested. It is found that within the validity range of the UTA approach, a good description of the opacity can be gained using a simple model provided that the linewidth is correct. Various simplified calculations of this width are tested, and found to be inaccurate [3]

Afghan Narcotrafficking Post-2014 Scenarios

As Afghanistan now faces an uncertain political and security environment following the drawdown of ISAF troops at the end of 2014, the potential for a worsening narcotrafficking threat is great. The report states that the potential for deterioration "underscores the imperative need for Russian and U.S. policymakers to find the political will to resume and perhaps even increase cooperation despite ongoing differences on other issues. Together with regional partners and international organizations, renewed Russian-U.S. cooperation presents the best hope for a brighter future.

Rational group ring elements with kernels having irrational dimension

We prove that there are examples of finitely generated groups G together with group ring elements Q \in \bbQ G for which the von Neumann dimension \dim_{LG}\ker Q is irrational, so (in conjunction with other known results) answering a question of Atiyah.Comment: 35 pages, 1 figure; [TDA 3/12/13:] Updated version incorporating referee's suggestion

The Development of a Comprehensive Database for Accident Analysis.

The Road Safety Code of Good Practice states that highway authorities should consider obtaining supplementary road safety data, to give a better assessment of the level of under-reporting and to improve the safety studies they undertake. This paper examines the extra sources of data that are available and used by highway authorities. It shows an improved system of linking police and hospital injury data and assesses the potential for the use of other such data. A questionnaire survey of all highway authorities in Britain was undertaken which showed that data sources such as traffic flows were used regularly, whereas others such as hospital data were rarely used. It was also found that when attempts were made to combine data much of the work was done manually. One of the most useful supplementary sources of information on accidents is hospital casualty data. A method of linking this with police reported casualty data by using, among other things, the name and address of the casualty has been shown to produce a considerably improved match than that in studies previously undertaken. This has thus been used to evaluate under-reporting and the nature of specific injuries to those involved in accidents. This study looks at the possibilities of including other data sources which could be used to assist authorities in validating accident forms and aiding in the selection of accident sites suitable for remedial treatmen

Recapturing the Spirit of Furman: The American Bar Association and the New Abolitionist Politics

Sarat locates the American Bar Association\u27s call for a moratorium on executions in the context of modern abolitionist politics. New abolitionism links anti-death penalty work with a broader civil rights agenda