Dynamic covalent oximes – tuning formation and exchange kinetics towards dynamic libraries and supramolecular architectures

Abstract not currently available

New dosimetry methods for radiological and nuclear emergency management

During all phases following a nuclear or radiological incident analyses of doses received by members of the public and responders are required. Rapid and reliable dose assessment is critical for the effective management of radiological emergencies; for medical triage, understanding exposure levels, directing protective actions, and conducting subsequent analyses of the impact of the incident. Current practice has been reviewed, highlighting the potential for near real-time luminescence dosimetry to assist with such assessments, including low dose response that supports public reassurance below doses of medical significance, using common materials present at the time of the incident. A number of materials which might be found in the immediate vicinity of people have previously been investigated with regard to their potential to act as radiation dosimeters. The work in this thesis investigates the properties of common household salt and talc, using portable Optically Stimulated Luminescence (OSL) and Infra-Red Stimulated Luminescence (IRSL) instruments capable of rapid measurements in the field. The potential of these materials to measure radiation levels and provide rapid, cost-effective insights into exposure patterns using new methods is explored. This approach aims to support emergency response strategies by leveraging accessible materials to improve decision-making in radiological incidents, bridging a key gap in large-scale radiation measurements and initial triage support. Common salt has previously been shown to have the potential for retrospective dosimetry in the mGy dose range using laboratory instrumentation. This thesis investigates the use of portable instruments, with unprepared commercially sourced salt, in dose ranges below mGy. Responses from pulsed IRSL laboratory systems and portable OSL instruments were compared. For OSL measurements, detection limits of 7µGy have been demonstrated, with detection limits of 30-340µGy for the other instruments investigated. Linear dose responses in the 0-500µGy range were determined over this dose range. This work examines the effects of signal stability and sample storage conditions. The OSL signals initially show a brief decrease in luminescence during the first few days after irradiation, followed by a gradual increase with longer storage periods. Between days 8 and 64, the results remain relatively stable, which is crucial for dose estimation during both the early and later stages of responding to radiological emergencies, and methods for correcting for these signal variations at shorter and longer periods have been developed and demonstrated. However, exposure to light and moisture leads to a rapid loss of OSL signals. Three practical experiments were conducted using salt to simulate real accident scenarios, measure radiation, estimate dose, and compare the results with gamma systems (backpack). The first experiment was conducted under controlled laboratory conditions. The second mapped natural and artificial radiation fields in an outside environment. The final experiment mapped complex radiation fields within an accelerator laboratory. The results demonstrate that salt has considerable potential for use in dosimetry below mGy and that measurements can be conducted with portable OSL instruments. Furthermore, the results of the first two experiments compared well to theoretical doses and measurements with different systems. The results confirmed that this approach can provide reliable dose estimates for radiological accidents. The salt system has demonstrated its ability to map the spatial boundaries of radiation fields, serving as a low cost radiation mapping tool. Protocols must be instituted for testing and assessment during exercises, taking into account variables such as zeroing, ambient conditions, and the necessity for fading adjustments. The studies of talc focused on the optimal conditions for measuring the radiation-induced OSLsignal using the SUERC Portable OSL Reader. It also addressed the inherent complexities associated with geological residual signals observed in talc sourced from Luzenac Pharma's packing line. This residual signal can be removed through thermal treatment, specifically at 400°C for 1 hour, after which the talc exhibits sufficient sensitivity to detect doses in the mGy range through to the radiologically significant range of 0.5 to 3 Gy, making it a promising candidate for field-deployable radiation assessment, such as in emergency response scenarios following radiological incidents. However, the observed fading and zeroing behaviours of talc introduce critical considerations that must be addressed to ensure reliable dose estimation. The fading data exhibit a complex decay pattern, suggesting the presence of multiple trap depths, with an initial signal loss of approximately 6% within 24 hours post-irradiation, escalating toa substantial 65% reduction of the original OSL signal within 128 days at ambient temperature. Such behaviour necessitates the incorporation of fading correction factors tailored to the time elapsed between irradiation and measurement, as an uncorrected signal loss could lead to systematic underestimation of doses, particularly in retrospective dosimetry applications. Additionally, the zeroing behaviour poses further challenges. Incomplete zeroing could leave residual signals that overlap with those induced by a recent radiation event. This overlap complicates the ability to accurately distinguish between background dose contributions and acute doses from a specific incident, potentially compromising the method’s specificity. The work presented here has demonstrated that the novel approach of using salt or talc with portable OSL systems is capable of delivering dose estimates in the range from a few µGy to several Gy in near real-time, complementing existing techniques. To optimize this approach, comprehensive protocols should be developed for both testing exercises and evaluations, which could lead to wider acceptance of these approaches offering a robust, low-cost solution for rapid dose assessment for both emergency response and environmental dosimetry

Attitude control and design of satellites with flexible structures using Inverse Simulation

Ensuring the stable and accurate pointing of a satellite’s instrumentation is the task of the attitude control system, a problem made substantially more complex by the influence of flexible structural dynamics often exhibited by satellites. The inclusion of flexible structures is necessitated by the desire to maximise the satellite’s functionality while ensuring its mass and form factor are conducive to being launched into orbit. Commonly, satellites will make use of lightweight and flexible, deployable appendages to facilitate the mounting of additional instrumentation, larger antennas, and extra solar panels. In addition, the construction of larger flexible space structures, using advancing orbital assembly and manufacturing technologies, opens the door to complex missions such as space stations, space telescopes, large solar sail spacecraft, orbital solar reflectors, and space-based solar power satellites. While the variety of applications for flexible space structures may be wide, each will require stable and accurate attitude control of the satellite platform. A range of attitude control methodologies for satellites with flexible structures has been studied previously, each attempting to achieve good tracking performance by imitating the satellite’s inverse dynamic behaviour. Many of these approaches are based on analytical techniques, requiring the control solution to be derived from a mathematical model that approximates the satellite’s dynamics. This thesis proposes that, if a sufficiently accurate mathematical model is available, then an alternative, highly-computational, numerical approach known as Inverse Simulation could instead be employed. Having already been demonstrated as a viable control methodology in several fields of research, such as planetary rovers and helicopters, this thesis will investigate the application of the generalised integral Inverse Simulation algorithm for attitude control of satellites with flexible structures. As part of the thesis, several mathematical models for the Inverse Simulation numerical process to solve are derived. This includes models that assume only rigid body behaviour, those that consider the flexible dynamics of deployable appendages, and finally a modular model for large flexible space structures. These models also account for the dynamics of various actuator types, some of which may have an impact on the stability and performance of the integral Inverse Simulation algorithm. The attitude reorientation manoeuvres used to drive the Inverse Simulation solution are provided using a mixture of polynomials, spherical interpolation, and splines. Before implementation as a control technique, the effect of each of the Inverse Simulation’s hyperparameters is studied to optimise the accuracy and computational efficiency of the algorithm. Additionally, issues of numerical stability specific to the application of satellites with flexible structures are identified and addressed. It is found that the integral Inverse Simulation algorithm does provide a more flexible, practical, and accurate method for solving the inverse attitude dynamics of a satellite with flexible structures than alternative analytical techniques. The generality of the numerical process allows for a ready-to-go control solution, provided a suitable up-to-date model is available. The control methodology is however highly sensitive to model uncertainty and requires significant computational power to compute, somewhat limiting its practical use. Additional online parameter estimation and improved computational efficiency of the algorithm will therefore be required if the control approach is to be realistically used. Inverse Simulation is also employed to improve attitude path planning, evaluating the performance of prospective paths to minimise excitation of the flexible structural dynamics. One of the most common applications of Inverse Simulation within the literature, as a conceptual design tool, is also demonstrated for satellites with flexible structures. It is shown that Inverse Simulation allows for the performance of different actuator configurations for large space structures to be assessed, informing designs that minimise structural deformation during slew manoeuvres. A final contribution of the thesis is the development of a faster integral Inverse Simulation algorithm based on Broyden’s method, improving performance particularly when a large number of inputs/actuators are in use

Crown Estate devolution: assessing the process, substance and rationale

This main goal of this thesis is to set out and analyse the process that led to the devolution of responsibility for the management of the Crown Estate to the Scottish Ministers, evaluating the strengths of that process with a view to determining whether it proceeded in a cohesive and logically consistent manner. This consideration of the process is accompanied by detailed scrutiny of aspects of the legislation that resulted out of that reform, arriving at a determination of whether the legislation is conducive to the resolution of the various issues that led to the consistent calls for reform. The thesis begins with a literature review that sets out the relevant academic writing and official publications concerning the Crown Estate in Scotland. This offers a foundation on which to proceed with analysing the strengths of the devolution of the Crown Estate. Also detailed is an example of dissatisfaction with the manner in which the Crown Estate Commissioners carried out their functions, focussing on their statutory duty to maximise revenues. The second chapter focusses on the political backdrop against which the reform of the Scottish elements of the Crown Estate took place, also providing insight into the politically divisive debates that were taking place in the Scottish Parliament and elsewhere, and whether the extent of this divisiveness hampered reform. The view can be taken that the Crown Estate is a particularly useful issue through which to analyse the transfer of power between legal and political institutions in the United Kingdom. The reasons for this are numerous: for example, the way in which management of the Crown Estate is governed and carried out has profound implications for the achievement of public policy goals in Scotland. Chapter three deals with the legislation that resulted out of this process, the Scottish Crown Estate Act 2019. The process that was engaged in during that Bill’s passage through the Scottish Parliament is found to be encouraging in terms of its rigorous Committee stages, under which a very wide variety of relevant stakeholders were consulted on how they believed long-term management of the assets should be guided. The chapter then analyses in detail the Bill at various stages, taking a specific interest in the economic and social duties placed on Crown Estate managers, as well as the provisions concerning further devolution to local authorities and community bodies. The thesis then adopts a theoretical perspective in Chapter 4 by seeking to ascertain whether a certain conception of property theory can be identified at each stage of reform. By this, it is possible to demonstrate the extent to which the Crown Estate in Scotland exemplifies an expansion in the obligations owed by property owners towards society, particularly by reference to the manner in which the new legislation broadened the duties of Crown Estate managers. The thesis concludes by taking the view that the initial reservation of management functions relating to the Crown Estate along with the continued reservation during the first decade of the Scottish Parliament were borne out of a desire to preserve the integrity of the United Kingdom. The Crown Estate, due to its proximity to the monarchy, is embedded with both emotional and practical relationships with the Union, and as such the Crown Estate is an understated focal point of any such devolution. The view is then taken that the Crown Estate demonstrates a divergence in policy between Scotland and the UK, with the former placing a greater emphasis on the extent of the obligations owed by property owners to wider society

Evidence synthesis of population health interventions: syntheses and advancing methods

Evidence synthesis of population health interventions often involves managing data from complex interventions and a diverse range of study designs, presenting challenges in applying synthesis methods to provide meaningful results. The work presented here provides examples of population health syntheses and research aimed at improving the conduct and reporting of both synthesis methods and primary studies that are used in syntheses. An initial essay provides a background on population health intervention evaluations and considers the implications, challenges and value of synthesising population health evidence. An overview of methods to develop guidance examines approaches to achieving consensus and the importance of supporting and managing the project team during guidance development. Three themes address evidence synthesis of population health interventions. In Theme 1, two reviews demonstrate the use of appropriate methods rigorously applied to population health evidence. The reviews examined the health impacts of social policies, mandatory participation in employment related programmes and participatory budgeting. Conducting these and other reviews developed my experience and ability to contribute to the projects in the following two themes. Theme 2 discusses three papers that advance systematic review methods by investigating and developing guidance on how to conduct and report synthesis robustly and transparently. The first paper provides guidance for conducting a systematic review of theories, illustrated and discussed using a worked example. The remaining two papers focus on narrative synthesis methods in systematic reviews. One is a methodological study to determine the adequacy of reporting of narrative synthesis of quantitative data in systematic reviews of population health interventions. This led to the third paper, guidance for reporting synthesis without meta-analysis (SWiM), an explanation and elaboration of nine checklist items designed to prompt systematic review authors to include key information when reporting the synthesis of quantitative effect data. Theme 3 consists of two sets of methodological guidance developed for reporting and conducting population health studies, both relevant for evidence synthesis. TIDieR-PHP is a guideline for reporting population health and policy interventions. Precise descriptions of interventions are crucial for synthesis and TIDieR-PHP prompts users on how to capture the features of interventions that are delivered to, or experienced by, large groups or populations, such as the policies examined in Theme 1. The second paper is guidance for using natural experiments to evaluate population health interventions. The guidance aims to prompt improved conduct and reporting of population health interventions, which is crucial to synthesising evidence of these interventions

Restricted and repetitive behaviours in autistic women: a mixed methods approach

Abstract available at each chapter

Braids: definition, recognition and survival. A journey from the Bronze Age to the Medieval: a taxonomy of braids: an explanation for archaeologists (and others)

Abstract not currently available

Characterising the dynamic tissue and immune response to radiotherapy in rectal cancer

Abstract not currently available

Towards sustainable and nature-based flood risk management in the Philippines

Abstract not currently available

Wellbeing in the UK PRS: a longitudinal analysis of outcomes for families and children

The housing system in the United Kingdom has seen substantial shifts over the last century, with its position amongst the policy priorities of government remaining consistently prominent. However, government ambitions regarding housing have taken different shapes and are reflected in those changes to the housing landscape, whether that be the clearances of poor-quality housing or the sale of vast swathes of social housing. There have been concurrent shifts in the demography of the private rented sector (PRS), also. In contrast to the common conception of the sector as a home to young people saving for a mortgage deposit, or those seeking mobility to access employment opportunities, the PRS now houses many who would prefer to live in other tenures. This includes those priced out of home-ownership and those who would have, in the past, been housed in social housing (SH). Increasingly, families and children have come to represent larger proportion of private tenants, while many renters are staying in the sector further into their lives. These changes represent a marked shift in the use of the PRS and one that is argued to have not been reflected in policy relating to it. This is of particular consequence for families, who lack the long-term security and agency in housing decisions that they need. Indeed, the UK’s lightly-regulated PRS is argued to be one that embodies insecurity. Alongside poor housing conditions and high housing costs, much qualitative research has found tenants face negative health effects owing to or exacerbated by the particular conditions of renting privately. This research does not show the scale of any effects, however. There is also little focus on families and children. While quantitative research on the effect of poor conditions on physical health has come to be well-represented in the literature, the impact on mental wellbeing remains little-studied in the UK context. To meet these evidence needs, this thesis has sought to answer the following research questions: Do wellbeing outcomes differ between tenure groups across the life course? Does exposure to the UK PRS in childhood impact mental wellbeing in later life? Do PRS tenants with children exhibit different mental wellbeing outcomes than those without? To answer these questions, the thesis analyses data from two of the UK’s largest cohort surveys, the 1970 British Cohort Study (BCS70) and the Millenium Cohort Study. Generalised Linear Mixed Models (GLMMs) are estimated on the BCS70 data in order to make robust estimates of effects over time. Generalised Linear Models (GLMs) and are also estimated to investigate effects in middle-age, while linear models are estimated on MCS data to investigate effects for a younger age cohort. The research finds generalisable effects across the life-course of PRS tenants, adding important evidence to the literature. Controlling for a range of influential factors, tenure-wide disparities in wellbeing are found to persist and even grow as tenants age, while parents in the PRS facing significantly worse outcomes than owner-occupiers approaching middle-age. Importantly, the research finds significant negative effects across the life course for those who have early-life exposure to the PRS. Young people in the PRS are also estimated to have poorer wellbeing in the younger age cohort, implying that the negative effects of living in the sector are being replicated for a younger generation. In light of these results, recommendations are made to ameliorate the negative consequences of living in the PRS and to make it a more secure and livable sector, as well as for further research to explore the effects found