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During the middle and late second century, aristocratic Roman society underwent a transition: from the apparently orderly and settled imperial court of Marcus, through the reign of Commodus, punctuated by plots and purges, to the brief imperial tenure of Pertinax, riven by dynastic scheming. This thesis uses a prosopographical study of the career of Pertinax, who was born the son of a freedman and rose to become emperor in 193, to examine the shifting socio-political structures of this imperial society. The goal of the thesis is twofold: firstly, to gain a deeper understanding of the process and consequences of the transition of aristocratic society from 160-93; secondly, to emphasise the career of Pertinax as representative of these changes. Apart from prosopography, the methodology revolves predominantly on the analyses of literary sources - textual and epigraphic - created within an aristocratic Roman context, although where necessary these sources are supplemented with numismatic and archaeological evidence. Such a methodology allows us to examine the structural characteristics of imperial society and enables the study of its responses and developments throughout the numerous crises and upheavals, internal and external, of the middle and late second century. Prosopography provides the central evidentiary framework for the thesis. The career of Pertinax, which took place under the emperors Marcus Aurelius, Lucius Verus, and Commodus (as well as his own brief three month reign), provides fertile ground for the prosopographical study of an imperial society in transition. His career has typically been treated in a supplemental or fragmentary fashion, and numerous problems deserve systemic treatment on historical and historiographical grounds. These problems in turn provide the cases studies within the thesis for discussions of the changing nature of imperial society and its relationship to the institution and person of the emperor.

Magma mixing and mingling processes are widely recognised in the textures and geochemistry of igneous rocks. A common feature of rocks from mixed magmas is the presence of magmatic xenocrysts, crystals that have been mechanically transferred from a magma of a different composition. This thesis investigates both the physical mechanisms of crystal transfer, and the physio-chemical response of crystals to the change in temperature and melt composition it experiences. Analysis of xenocrysts in lavas from Unzen, Japan, demonstrates how an understanding of these processes can inform interpretations from textural and geochemical analyses. Experimental and numerical studies investigate the fundamental process of low Reynolds number gravitational settling of spheres through fluid interfaces as an analogue for crystal transfer. Experiments reveal the dominant control on the volume of fluid entrained during the transfer is shown to be the viscosity ratio, with significant entrainment occurring when the viscosity of the upper fluid is comparable or greater than that of the lower. However, boundary integral method simulations suggest the density contrasts between crystals and melt are too small for gravitational settling to account for crystal transfer between magmas. Plagioclase and quartz xenocrysts in a mafic enclave erupted at 4-5 ka from Unzen are analysed to determine the effect of transfer on their textures and chemistry. Plagioclase xenocrysts contain resorbed interiors, surrounded by Fe-rich rims of clear growth, whilst quartz are rounded, heavily embayed and surrounded by coronas of hornblende, glass and vesicles. 50% of plagioclase phenocrysts in the host magma have signatures of previous resorption events, suggesting repeated episodes of injection and crystal recycling in the magma storage system prior to eruption. Erupted lavas from 1792 and 1991-1995 suggest such processes have been occurring for the last 300 years, but this study suggests they have possibly been ongoing for at least 5000 years.

The increase in obesity prevalence over the past 20 years has become an international public health crisis. The lack of timely, accurate information led to a six year delay in recognising the obesity epidemic in UK children, despite height and weight measurements of children at various ages being routinely collected for many years. The chain of data, analytical methods and public health expertise for child obesity analysis and public health reporting is fragmented. This fragmented workflow leads to delayed or lost intelligence and public health decision-makers have little control of the underlying systems to produce the intelligence they require. This research addressed the specific need for a public health intelligence workflow system to profile child obesity. A web based software system known as Obesity Atlas was developed with and for the Greater Manchester Primary Care Trusts. In both requirements analysis and evaluation it was found that the combination of statistics, charts, and geo-visualisation are more informative if chained together in a workflow than used separately. In order to inform more public health decisions with current resources, there is a need for a common framework for finding, sharing, enacting, and re-using public health intelligence workflows.

Spatial datasets contain information relating to the locations of incidents of a disease or other phenomena. Appropriate analysis of such datasets can reveal information about the distribution of cases of the phenomena. Areas that contain higher than expected incidence of the phenomena, given the background population, are of particular interest. Such clusters of cases may be affected by external factors. By analysing the locations of potential influences, it may be possible to establish whether a cause and effect relationship is present within the dataset. This thesis describes research that has led to the development and application of cluster detection and feature selection techniques in order to determine whether causal relationships are present within generic spatial datasets. The techniques are described and demonstrated, and their effectiveness established by testing them using synthetic datasets. The techniques are then applied to a dataset supplied by the Welsh Leukaemia Registry that details all cases of leukaemia diagnosed in Wales between 1990 and 2000. Cluster detection techniques can be used to provide information about case distribution. A novel technique, CLAP, has been developed that scans the study region and identifies the statistical significance of the levels of incidence in specific areas. Feature selection techniques can be used to identify the extent to which a selection of inputs impact upon a given output. Results from CLAP are combined with details of the locations of potential causal factors, in the form of a numerical dataset that can be analysed using feature selection techniques. Established techniques and a newly developed technique are used for the analysis. Results from such analysis allow conclusions to be drawn as to whether geographical causal relationships are apparent.

The application of radiation detector materials, capable of operating at room temperature, has been studied. The advantage of such materials is that they do not need to be cooled to reduce thermally generated leakage currents. Therefore, systems utilising these detectors can be smaller and more portable than ones containing HpGe and Si(Li) detectors which need to be cooled using liquid nitrogen to reduce leakage current. Three materials, silicon, cadmium telluride and mercuric iodide, have been investigated. The silicon photodiode showed very good energy resolution down to photon energies of 13.4keV, but its low detection efficiency restricts its use to energies below 200keV for direct detection. Cadmium telluride produced energy spectra with worse energy resolution, due mainly to charge collection, leakage current and fabrication. But, cadmium telluride was able to produce spectra up to 661.6keV with reasonable efficiency and resolution. Mercuric iodide produced spectra with energy resolution on a par with the silicon photodiode but with a higher detection efficiency. Mercuric iodide crystals have been produced at Surrey using the polymer assisted transport growth method. A large crystal with dimensions exceeding 1cm3 has also been produced. Due to problems with application of electrical contacts no useful spectra were obtained with these devices. The importance of the polymer in the starting material was investigated. The addition of polyethylene was found to favour the growth of platelets. The size of the platelets was also found to increase with increasing proportion of polymer in the stalling mix. A computer simulation enabling the performance of semiconductor radiation detector materials to be predicted is also presented. The model follows processes from photon interactions in the detector through to charge collection. Energy spectra may be produced from the output of this model and energy resolution and detection efficiency may be analysed as a function of detector thickness, applied bias and photon energy. This model could be used to optimise performance of radiation detectors.