A New Class of Quantile Processes with Applications in Risk Analysis and Valuation

This thesis presents a novel approach for the construction of quantile processes, governing the stochastic dynamics of quantiles in continuous time. Two constructions are proposed, one producing a function-valued quantile process and the second, a process with random quantile levels. The latter method employs a distortion map composed of a distribution function and a quantile function, similar to a transmutation map, applied to each marginal of a 'driving' process with cadlag paths. A multidimensional extension that utilises a copula is also presented. As a result, we obtain a one-step approach to constructing widely flexible classes of stochastic models, accommodating extensive ranges of higher-order moment behaviours (e.g., tail behaviours in the finite dimensional distributions, and asymmetry). Such features are parameterised in the composite map and are thus interpretable with respect to the driving process. Sub-classes of quantile processes are explored, with emphasis placed on the Tukey family of models whereby skewness and kurtosis are directly parameterised and thus the composite map is explicable with regard to such statistical behaviours. It is also shown that the quantile processes induce a distorted probability measure that is interpretable in its properties (which may be intentionally constructed), leading to the central application developed in this thesis. We propose a general, time-consistent, and dynamic risk valuation principle under the induced measures of quantile processes, allowing for pricing in incomplete markets and thus having application in insurance pricing. Here, the distorted measures are considered 'subjective' and are constructed in such a way to account for external market characteristics and investor risk attitudes, leading to a parametric system of risk-sensitive probability measures, indexed by such factors. The properties of the valuation principle based on the quantile process distortion measures are discussed with regard to stochastic ordering and risk-loadings, and a case study is presented where insurance instruments linked to greenhouse gas emissions are considered

The development of a point of care device for measuring blood ammonia

Ammonia is produced in the body during the metabolism of amino acids. In the liver, it is converted to urea via the urea cycle and excreted by the kidneys as urine. Normal levels are between 11 to 50 µM, whereas a blood ammonia level of approximately 100 µM indicates pathology. Elevated blood ammonia is associated with a number of pathological conditions including liver and kidney dysfunction. Conditions such as these can affect brain function and can be fatal. Current blood ammonia analysis requires a laboratory blood test. Few, if any of the techniques used are suitable for point of care (POC) testing. The development of a reliable and simple method for blood ammonia determination is essential for clinical diagnosis and management of patient progress in order to prevent further debilitating illnesses developing, and extending life. This is particularly critical in many disorders such as hyperammonaemia of the newborn, inborn errors of metabolism including urea cycle defects, organic acidaemias, hyperinsulinism/hyperammonaemia, liver disease and other cause of hyperammonaemic encephalopathy. This thesis investigates the development of an electrochemical sensor for the measurement of ammonia in blood. Polyaniline has a known affinity for ammonia which operates on the deprotonation of the polyaniline backbone forming an ammonium ion. In this work, polyaniline nanoparticles were fabricated and inkjet-printed onto silver screen printed electrodes. The sensors were then incorporated into devices containing a gas-permeable membrane, which facilitated the measurement of gaseous ammonia from a liquid sample (blood) using electrochemical impedance spectroscopy. The combination of impedance spectroscopy with a gas-permeable membrane allowed the measurement of gaseous ammonia from solution. The ammonia device developed possessed refinements to enhance its sensitivity and included careful optimisation of other aspects of the measurement. For example, an air purge through the device gas chamber was employed to remove matrix interferences from the sensor and improve the specificity to ammonia. The pH of the sample to be analysed was modified in order to increase the mass of ammonia in solution, thus lowering the limit of detection (LOD) of the device. Finally, assay timings were optimised in order to increase the impedimetric response of ammonia. These optimisations resulted in the effective detection of ammonia in a liquid sample down to the lowest clinically relevant levels found in blood. The devices displayed an impedimetric baseline intra- and inter-variability of 25 and 6.9%, respectively for n = 15 over a period of 160 s. A calculated limit of LOD of 12 µM was achieved for human serum measurements. A coefficient of determination of 0.9984, slope of 0.0046 and an intercept of 1.1534 was obtained in human serum across the linear range of 25 to 200 μM ammonia (n = 3). The device was validated against a commercial spectrophotometric assay which resulted in excellent correlation (0.9699, p < 0.0001) with a slope of 1.4472 and an intercept of 0.5631 between both methods (n = 3). The devices could be stored in desiccant for up to five months and displayed minimal variation (0.64%) over time (n = 12)

On being outdoors: How people with dementia experience and deal with vulnerabilities

Vulnerability is a problematic label routinely applied to people with dementia, yet their situated experiences of vulnerability have not been prioritised or documented. Drawing on empirical data collected using a novel methodology - walking interviews with 15 people with dementia living in Southern England, followed by a sit-down interview that included a nominated family member - this paper advances understanding of how vulnerability is experienced and dealt with by people with dementia when outdoors, and at times shared with family carers. Data were analysed using abductive techniques; a thematic coding framework was created from the dataset, in addition to the application of critical theories of vulnerability and disability. We found that vulnerability is characterised by a sense of ‘ontological vulnerability’ for the person diagnosed with the condition - that is, an awareness of failing knowledge about oneself or the ‘rules’ of outdoor life, which individuals experienced emotionally and dealt with civically. People with dementia attempted to manage risks and anxieties, often doing this independently so as not to burden family members. These findings highlight how people with dementia experience and deal with vulnerability when outdoors, which others need to acknowledge and support to enable people with dementia and their families to work though these challenges, in a family-orientated way when risk planning

Future Studies, Mental Health and the Question of Citizenship

Purpose: This paper seeks to examine the value of utilising future studies to explore citizenship for people with mental health challenges. Design/methodology/approach: This paper critiques the discipline of future studies and considers it in the context of the citizenship and mental health literature. It explores how future studies can be utilised to promote marginalised voices, such as those of people with mental health challenges. Findings: Technology is leading to rapid change in society including what it means to be a citizen (Isin and Nielsen 2008; Isin and Ruppert 2015). Whilst citizenship has been promoted within mental health for a long time, change has been slow (Rowe and Davidson, 2016). In order to create inclusive opportunities for people with mental health challenges, any focus on citizenship in mental health needs to not only address the present time but to anticipate and influence future technological directions. Originality/value: This paper is original in bringing together mental health and the future impact on society of new technologies. It stands to offer a new perspective to discussions on citizenship

An Ethics of Care Research Manifesto

Participatory methodologies are frequently used in social research and have matured over the past decades. Ethical aspects of participatory research feature in retrospective accounts of partnerships that contribute to quality research, and those that were problematic to negotiate in the research partnership. Meanwhile, social researchers have shared concerns about meaningful transformations from research and the processes involved to achieve effective, responsive partnerships. As participatory methodologies have matured, so has an ethics of care. An ethics of care research manifesto provides a framework for surfacing marginalisation and potential for transformation, considering interdependencies, and negotiating research relationships with the broader research community

Citizenship and people living with dementia: A case for the ethics of care.

The ethics of care is an emerging field of interest in many disciplines, including care for people with dementia. The ethics of care as proposed by Joan Tronto is a political argument for care together with a set of principles, the integrity of care, to guide and critique practice. This two-pronged approach enables on one hand, a political, complex and situated examination of inequality, and on the other hand the integrity of care provides a set of principles to guide inclusive citizenship practices. This approach has the significant advantage of recognition of the fight that people with dementia face to achieve rights and citizenship as an issue of social justice. In this paper, three challenges to citizenship are discussed in relation to people with dementia using an ethics of care lens: (a) citizenship as a relationship between the individual and the state; (b) citizenship as a practice and (c) citizenship as identity and belonging. I propose that citizenship can be achieved by promoting inclusion in defining and creating policy, research and practice

Supporting Indigenous and Non-Indigenous Research Partnerships

This commentary discusses the framing of the production of a series of online text-based and visual resources aimed at researchers embarking on Indigenous and non-Indigenous research partnerships, and in particular supporting non-Indigenous researchers to think about our/their methods, assumptions and behaviour. We identify the tension in mainstream funding for such partnerships, and discuss the implications of Northern epistemological claims to agendas and universality as against Southern epistemologies acknowledging diversity and challenging oppressions. We note the distinct bases for Indigenous methodologies. Our commentary outlines and illustrates the online downloadable resources produced by our own Indigenous and non-Indigenous research partnership, including a video/audio recording, a comic, and blog posts, addressing decolonized collaborative practice

Supporting Indigenous and Non-Indigenous Research Partnerships

This commentary discusses the framing of the production of a series of online text-based and visual resources aimed at researchers embarking on Indigenous and non-Indigenous research partnerships, and in particular supporting non-Indigenous researchers to think about our/their methods, assumptions and behaviour. We identify the tension in mainstream funding for such partnerships, and discuss the implications of Northern epistemological claims to agendas and universality as against Southern epistemologies acknowledging diversity and challenging oppressions. We note the distinct bases for Indigenous methodologies. Our commentary outlines and illustrates the online downloadable resources produced by our own Indigenous and non-Indigenous research partnership, including a video/audio recording, a comic, and blog posts, addressing decolonized collaborative practice