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The move out of compulsory education is a key transition period in adolescents' lives. The aim of the present study was to investigate physical activity and sedentary behaviour (using 'screen time' as the proxy measure) among adolescents during the transition from completing compulsory education to entering further education, training or (un)employment. A prospective population-based longitudinal design was adopted, using a large cohort of adolescents in Gloucestershire. A questionnaire was administered to participants at two time points (baseline and follow-up). At baseline, 2204 Year 11 pupils (aged 14 to 17 years) and at follow-up, 886 participants from the baseline sample (aged 15 to 17 years) completed the questionnaire. ( For all statistical analyses performed, two sets of analysis were conducted. Analysis one included the final sample of participants (n = 663) who had an associated output area (OA) code to include in statistical analyses and analysis two included the final sample of participants (n = 834) who did not have an associated OA code included in statistical analyses. Since the overall findings for each analysis were similar, only findings from analysis one are presented. For physical activity, there was a significant change in the number of participants meeting guidelines at baseline but not meeting guidelines at follow-up. For screen time status, there was no significant change between baseline and follow-up. Binary logistic regression (BLR) revealed that for gender, in comparison to males, females were 52.4% less likely to meet guidelines for physical activity at follow-up. Meanwhile, BLR revealed that there were no significant associations with screen time status at follow-up. Further BLR for the decline in physical activity through the transition, revealed that for gender, in comparison to males, females were 42.4% less likely to move from meeting guidelines at baseline to not meeting guidelines at follow-up (i.e., physical activity decline was associated with being male). The findings of the present study have demonstrated: i) a decline in physical activity through the transition; ii) the high proportion of adolescents not meeting guidelines for screen time at either baseline or follow-up; and iii) associations between gender and physical activity during this transitional period. There is a need for future research to longitudinally examine adolescents' physical activity and sedentary behaviour during this transitional period.

One reason for studying and programming in functional programming languages is that they are easy to reason about, yet there is surprisingly little work on proving the correctness of large functional programs. In this dissertation I show how to provide a system for proving the correctness of large programs written in a major functional programming language, ML. ML is split into two parts: the Core (in which the actual programs are written), and Modules (which are used to structure Core programs). The dissertation has three main themes: Due to the detail and complexity of proofs of programs, a realistic system should use a computer proof assistant, and so I first discuss how such a system can be coded in a generic proof assistant (I use Paulson's Isabelle). I give a formal proof system for proving properties of programs written in the functional part of Core ML. The Modules language is one of ML's strengths: it allows the programmer to write large programs by controlling the interactions between its parts. In the final part of the dissertation I give a method of proving correctness of ML Modules programs using the well-known data reification method. Proofs of reification using this method boil down to proofs in the system for the Core.

Safe water supplies are fundamental to public health protection. The assessment and control of pathogen risk is of primary concern, as a large disease burden is prevented. Due to the insensitivity of laboratory techniques and public health surveillance, quantitative microbial risk assessment (QMRA) is used to quantify public health risk associated with water supply. This thesis aims to establish new evidence to inform QMRA policy and practice. It does this from the perspective of a practitioner-researcher. This thesis comprises three analytical studies. Each answers a research question arising in the professional practice of the researcher. The first study uses the systematic review method to synthesise usage patterns of QMRA for drinking water supplies globally. The second uses interrupted timeseries analysis to examine an intervention into the sensitivity of protozoal enumeration results used in QMRA. The final study uses stochastic QMRA modelling to examine the fitness of a new method, detailed verification , for the routine quantification of public health risk for water recycling. The studies are contextualised by a narrative literature review, a narrative case study, and an overarching discussion and conclusion. The first study found that current QMRA approaches varied most for deriving dose, that dose was influential in determining risk, and that the complexity of selected QMRA approaches is generally incommensurate with the purpose served. The second study found that the intervention overall provided greater precision of public health risk estimation. The intervention was associated with an around two-thirds reduction in the estimated public health risk associated with Cryptosporidium and Giardia (rate ratio [RR] = 0.35, p < 0.05, and RR = 0.32, p < 0.001, respectively) in one system, and an increased frequency of non-zero protozoal counts in three scenarios (p < 0.05). The third study found that quantitative public health requirements were met. Sensitivity analysis found that assumptions relating pathogen to surrogate levels were influential on the probability of infection (Spearman s rank correlation co-efficient, ρ, = 0.38 to 0.90). This thesis establishes new evidence for QMRA implementation for public water supplies. Its findings will support public health protection through the improved assessment and control of pathogen risk.

Population growth and cars have caused cities to sprawl from their downtown cores, resulting in a landscape of low density building. Far too often the empty lot at the edge of the city or along a highway attracts the next opportunity for development, furthering the gap between residential and commercial zones. The profession of architecture recognizes that urban site selection and mixed-use programming is vital to the social and financial health of a city, though it typically only participates in the design of the building. However, the visionary training and practice of architecture places the architect in a unique position to initiate successful projects on sites that are undervalued. That reality suggests that the architect’s role in the process of development should be expanded in order to participate in programming and site selection. This expanded role will lead to more frequent and better quality urban development which is supported by financial incentives for cities, developers, and architects.

Until recently, the research on refugee populations has been part of migration studies, with little distinction made between the two populations. The focus of research has always been on the movement rather than the motivations behind the movement. It has been generally assumed that refugees would make the same overall choices that immigrants make upon arrival in their areas of destination. Yet as this study establishes, the experiences of refugees are radically different from those of voluntary migrants, and refugees do not typically have the advantage of choosing their destinations. This research begins from the perspective that the essential difference between refugees and immigrants is the aspect of choice. Theoretically at least, an immigrant has a choice whether or not to migrate, while the refugee has no such option. A voluntary immigrant at least has the option of staying where they are without suffering any penalties (beyond opportunity costs) for this action, while refugees must move or face serious consequences. This research establishes refugees as a distinct sub-group within the greater population of international immigrants. This allows a finer level of detail in future research and allow policy makers to tailor their programs to better meet the needs of their target constituents. The first set of questions this research addresses is, “What are the differences in the characteristics of refugees as compared to voluntary migrants?” The next question is, “In what aspects do refugees differ from voluntary migrants and what does this mean for employment prospects, assimilation or multiculturalism, spatial distribution, community development, programmatic needs, and policy making?” This set of questions will be analyzed using the quantitative methods applied to the data provided by the 2003 New Immigrant Survey (NIS), conducted by Princeton University. The next research question will be “What effects do these differences have on the experiences of refugees in their host country (the U.S.)?” This question deals with the key issues that interest researchers of immigration: how the differences between refugees and immigrants manifest themselves in their actions and living situations. This research will begin to explain the effect refugee status has on an immigrant’s ability to utilize their human capital in the host country. Human capital for this study will be measured by years of education and work experience in the home nation.Finally, this study investigates the detailed experiences of refugees as they have undergone the process of displacement and resettlement in the United States. This stage of research will also focus on the strategies and resources utilized by refugees in overcoming the barriers they confront during this process. This stage of the research process will focus exclusively on qualitative interviews of Somali refugees and key informants living and working in central Ohio.