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This thesis presents new results on probabilistic error analysis. By freeing ourselves of the burden of having to account for every possible worst-case scenario, we provide error bounds that are more informative than the long standing worst-case bounds. We also see in practice how these new bounds can guide the development of new algorithms. We begin by studying stochastic rounding, a rounding mode which rounds a computed result to the next larger or smaller floating-point number randomly. We compare stochastic rounding with round-to-nearest, finding some similarities but also a large number of properties that hold for round-to-nearest but fail to hold for stochastic rounding. Importantly, we show that the rounding errors produced by stochastic rounding are mean zero, mean independent random variables. Using this fact, we build on earlier probabilistic error analysis to show that for a wide range of inner product based linear algebra computations, stochastic rounding provides backward error bounds where we can take the square root of the dimensional constants in the worst-case bounds. This has been a well known rule of thumb for some time, but we show it to be a rule for stochastic rounding. Expanding on this work for inner-product based algorithms, we investigate orthogonal transformations. Using the same model of rounding errors as that which stochastic rounding satisfies, we show that for Householder QR factorization, and other related algorithms, we see the same square rooting of the dimensional constant in the backward error bound. The analysis makes use of a matrix concentration inequality, where previous probabilistic error analyses employed scalar concentration inequalities. We also derive a new backward error formula for QR factorization, used in our numerical experiments which validate our bounds. Finally, we consider the randomized SVD, a well known method for computing low rank matrix approximations. We perform a complete rounding error analysis of the fixed-rank problem, the most straightforward version of the randomized SVD where we have a priori specified a target rank. This is complementary to the existing literature providing error bounds on this procedure in exact arithmetic. While our initial analysis is worst-case, we use our previous probabilistic results to refine these error bounds. Using these refined bounds, we propose a mixed-precision version of the algorithm that offers potential speedups by gradually reducing the precision during the execution of the algorithm.

Enzymes are biological catalysts which are crucial for life and are fundamental in many important processes in organisms. The temperature dependence of enzyme-catalysed reactions is important for homeostasis, and until recently the drop-off in enzyme-catalysed reaction rates at higher temperatures has been attributed to protein denaturation. It has been shown experimentally that rate drop-off occurs in the absence of denaturation. Macromolecular rate theory (MMRT) does not assume that enthalpy and entropy changes are independent of temperature, introducing an activation heat capacity term, ∆C_p^‡ to understand the curvature of reaction rates, even in the absence of protein denaturation. Molecular dynamics (MD) simulations can provide insight into dynamical behaviours of proteins and have previously been used for the calculation of thermodynamic properties including heat capacities. In this thesis, MD simulations are used to calculate ∆C_p^‡ for two different enzyme-substrate complexes. The results show that a negative ∆C_p^‡ value is generally obtained from MD calculations for these enzymes, which agrees with the experimentally observed curvature for the enzyme-catalysed reaction rates. Principal component analysis, Kullback-Leibler divergence and hidden Markov state modelling techniques are all utilised to analyse the origin of the dynamical changes in the protein chain leading to a negative ∆C_p^‡ term. The work in this thesis shows that MD simulations can be used to provide insight into MMRT and the dynamical properties of enzymes, and points to potential future work in understanding how the optimum temperature for enzyme-catalysed reactions is influenced by the dynamics of the protein chain of an enzyme.

This thesis critically explores the life of Brother Walfrid (Andrew Kerins), one of the most significant Irish immigrants to Britain, in relation to his contribution to Catholic education and charity, as well as organised sport in Scotland in the late nineteenth century. Despite knowledge around him as a prime founder of Celtic FC, Walfrid's story remains largely untold. This research investigates the 'real' Brother Walfrid - the man separated from myth - along with his legacy among the multi-generational Irish Catholic community in Scotland, and elsewhere. This study analyses the origins of Andrew Kerins beginning with his Sligo birth and departure for Glasgow. Drawing on surviving historical and archived documents, the effects of An Gorta Mor (the Great Hunger in Irish) on Kerins and his family are reflected upon. Further, new information drawn from contemporaneous publications and interviews provided the source material on this epochal figure for the Irish Catholic diaspora. The socio-economic circumstances that provided the conditions for the emergence of Celtic FC - a unique representation of the Irish diaspora in world sport - are explicated through this biography of Brother Walfrid's lived experience. Critically, it also seeks to understand and explore Walfrid's role, motivations and achievements as a Marist Brother: especially with respect to his importance to Catholic religious, educational, charitable and cultural identities in Scotland. Walfrid's integral role in the creation of Celtic FC is critically reappraised along with his faith and charity work amongst the poor and marginalised in Glasgow. By producing a full account of the life of Brother Walfrid, what emerges is a more substantive insight into a figure of totemic historical significance for the Irish Catholic diaspora, in Scotland and beyond. Through the combination of faith, charity and football, Walfrid's life illustrates a historic contribution to Irish Catholicism in nineteenth century Britain.

'Autism Plus' is a concept which relates to individuals with Autism Spectrum Condition (ASC) and co-occurring conditions (Gillberg & Fernell, 2014). Three studies reported in this thesis examined evidence for a key premise of Autism Plus, namely that individuals with Autism Plus experience poorer social and independent living outcomes and greater support needs compared to those with 'Autism Only' (i.e. those with ASC but no co-occurring diagnoses). Study One was a secondary analysis of survey data from secondary data analysis of 404 adults with autistic disorder (n = 82), Asperger's/High-Functioning Autism (n = 236) and other ASCs (n = 86). A series of chi-square analyses comparing employment, relationship, residential and independent travel outcomes and service pattern use between those with Autism Plus and Autism Only. No group differences were found in employment or travel outcomes, though contrary to the premise of interest here, those with Autism Plus were found to be more likely to live independently and to be in long-term relationships. However, in line with the premise, those with Autism Plus were more likely to have used support services in the six months prior to data collection. In Study Two, logistic regression analyses focusing on the same sample explored whether Autism Plus may better predict poorer adult outcomes as part of a larger model accounting for age and autistic symptom severity. Findings indicated that Autism Plus was not a useful predictor of employment or independent travel outcomes as part of this model, though again indicated that those with Autism Plus were more likely to live independently and to be in long-term relationships. Other key findings indicated that outcomes were better amongst older individuals and those with milder autistic symptoms. Study Three aimed to gain greater insight into the ways in which co-occurring diagnoses could influence the lives of those with ASC through interviews with adults with Autism Plus. Analysis of accounts of lived experience using Interpretative Phenomenological Analysis (IPA) supported the view that the participants' co-occurring symptoms added considerable disruption and difficulty to their lives, and at times could have a greater impact than their ASC symptoms. There was also evidence that within the context of Autism Plus, the severity of a co-occurring condition may be as important as its presence. Overall, the evidence reported here indicates that current conceptualisation of Autism Plus is limited in the extent to which it can predict those with ASC most likely to experience poor outcomes, though may be helpful in establishing those most likely to require support. Given the findings from Study Two and Three, it is recommended that a modified version of Autism Plus, which considers Autism Plus as an important component of a larger model and acknowledges co-occurring symptom severity, should be explored further.

The definitions of discrimination provided by equality legislation are a measure of how far a society is willing to challenge deep-seated assumptions, attitudes, and patterns of inequality. The judiciary has a major role in shaping these definitions. This is evident from the antecedent American cases and those of the Court of Justice of the European Union, which worked with more aspirational than detailed legislative provisions. One might conclude that the legislation coming before the English courts was thus ‘ready-made’, presenting the judiciary with few interpretive difficulties. But on many occasions this has proved not to be the case, with the senior English courts producing a number of highly contentious decisions. Commentators, heavily critical of many of these cases, tend to analyse them by reference to external understandings of concept, theory, or policy. This work offers a unique internal critique of the process producing the cases subject to such academic scrutiny. It makes a textual analysis of leading English judgments on the definitions of discrimination, and does so through the lens of statutory interpretation - the judge’s primary function. The scrutiny finds that these judgments are technically flawed in terms of the process of statutory interpretation and the definitions produced; it also finds them to be overcomplicated, excessively long, and often unduly restrictive. As such, the thesis is that these cases were better, and more easily, resolvable using conventional methods of interpretation, which would also shape the definitions better to reflect the policies underlying the legislation. Although highlighting inexpert reasoning, the textual scrutiny reveals other threads, particularly notable in the narrow interpretations. There is an adherence to the common law’s notion of binary litigation, envisaging just two individual litigants (e.g. a worker and employer) necessitating a harmed individual and fault-based liability; this is at odds with the societal and group-based purpose of the legislation. One can also detect a lingering historical negative or indifferent attitude to matters of equality, often realised nowadays with an assortment of personal predilections. Consequently, suggestions for reform are based around these findings.

Epidemiological studies have reported an inverse association between wholegrain and risk of cardiovascular disease, diabetes, obesity and some forms of cancer. However, the mechanisms of wholegrain protection against these diseases are poorly understood. Two characteristics of wholegrain that may impact on health are the glycaemic index (GI) and potential to modulate the colonic microbiota. A diverse population of microorganisms resides in our colon, known as the gut microbiota. These bacteria may play an important role in these diet-associated diseases and the diet microbe interaction is a topic of specific interest. Consumption of most wholegrains results in a low insulin response (low glycaemic index (GI)). Processing often leads to detrimental effects on this beneficial attribute and may in turn also alter potential to modulate the gut microbiota. A number of in vitro experiments were performed to investigate how processing and cooking of oat, wheat and wholegrain pasta impact on the ability of these foodstuffs to beneficially modulate the gut microbiota. Processing and cooking impacted negatively on favourable bacteria and short chain fatty acid profiles in the in vitro faecal microbiota fermentations. Using in vivo and in vitro methods, a low glycaemic index, potentially prebiotic whole grain oat (WGO) breakfast cereal was identified. Effects on markers of cardio-metabolic risk and colonic microbiota after 6-week daily consumption of WGO were explored in subjects, who had either or both, slightly elevated levels of fasting glucose and total cholesterol. Numbers of total bacteria, Bifidobacterium and Lactobacillus significantly increased, while a significant decrease in total cholesterol was observed after the WGO compared with a control cereal. This thesis shows that processing of wholegrain adversely affects GI and reduces their potential as prebiotic food. Furthermore, consumption of a low GI, prebiotic WGO cereal was observed to successfully modulated the gut microbiota towards a favorable composition and resulted in hypocholesterolaemic effects. This supports the hypothesis that microbiota modulation may confer cardio- metabolic health benefit.

In the wake of the financial crisis of 2007-2009, academics and policymakers have worked to empirically quantify macro-financial linkages. This dissertation contributes to this debate by covering two broad themes. First, substantial changes in bank regulation and supervision typically follow financial crises. Quantifying the impact of these new policies is of paramount importance to academics and policymakers. To this end, my research in this area sheds light on the ways in which changes in financial stability policy ultimately affect the economy. Bank stress testing has become a major tool of supervisory policy in the past decade. The first chapter, The Real Effects of Stress Testing, uses the introduction of annual stress testing of large U.S. banks in 2009 as a quasi-experiment to examine whether bank supervisory policies affect real economic activity. While stress-tested banks reduced their risk exposure to large corporate loans, foreign banks mostly offset this shock and enabled firms to continue borrowing after the test. However, speculative grade firms that were highly exposed to stress-tested banks borrowed on worse terms after the test, and subsequently reduced fixed investment and employment. In contrast, highly exposed investment grade firms received new loans and expanded intangible investment. This paper provides insights into the effects of stress testing on the reallocation of risks in the financial system and the consequences for real economic activity. The structure of the U.S. mortgage market has experienced dramatic changes in recent years, as Fannie Mae and Freddie Mac (the major government-sponsored enterprises or GSEs) faced substantial reforms to their business practices. An important feature of regulatory reform included changing the pricing of loan guarantees on mortgage-backed securities insured by the GSEs, in particular removing the subsidy paid by small lenders to large lenders in 2012. The second chapter of this dissertation, Lender Cross-Subsidization and Credit Supply in the Fannie Mae MBS Market (co-authored with Igor Karagodsky), shows that the removal of this subsidy resulted in a relative increase in mortgage lending by small lenders. However, states with relatively higher concentrations of large lenders experienced relative reductions in credit following the removal of these subsidies. This research underscores an important link between lender market power and credit supply. Understanding the drivers of the fluctuations in bond returns is a central question in finance. Theoretically, unexpected bond returns should reflect either changes in expectations of future short-term rates or future compensation for risk. The third chapter of this dissertation, Survey Forecasts and Bond Return Decompositions, revisits this question using survey forecasts of professional economists to measure expectations of interest rates and returns, rather than with a statistical model. Two main results emerged from this analysis: (1) News about future short-term interest rates explains relatively more of the variation in unexpected excess bond returns for short-maturity bonds relative to long-maturity bonds. (2) The share of news explained by future short-term interest rates increases with horizon for all maturities. This analysis contributes to the recent academic literature that highlights the importance of subjective expectations in understanding asset-price movements.

Adapting the limited memory of microcomputers to solve large scale manufacturing problems.