VictorJuiz/thesis huggingface dataset:
A study of CP violation and measurement of the CKM angle γ in B0→ DK∗0 decays
Keywords: CP violation
B mesons
Large Hadron Collider
CKM triangle

Two measurements of CP observables in B0 → DK∗0 decays are presented, where D represents a superposition of D0 and D0-bar states. The measurements use samples of proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV.
The first measurement uses 5 fb−1 of data with the D meson reconstructed in the two-body final states K+π−, π+K−, K+K-, and π+π−, and, for the first time, in the four-body final states K+π−π+π−, π+K−π+π-, and π+π-π+π−. First observations of the decays B0 → D(π+K−)K∗0 and B0 → D(π+π−π+π−)K∗0 are obtained, and a set of observables comprising yield ratios and asymmetries is studied. The second measurement studies D-meson decays to the three-body final states KS0π+π− and KS0K+K− in a binned Dalitz plot analysis using 9 fb−1 of data.
The CP observables from both measurements are interpreted together to determine the CP-violating weak phase γ = (77+8-9)◦. This is the world’s most precise determination using only B0-meson decays and is in agreement with the prediction of the Standard Model. The world’s best measurements of the hadronic parameters r_B = 0.258+0.022-0.023 and δB0 = (200 ± 8)◦ are also presented.
Feeling all the (partisan) feels: Exploring the drivers of affective polarization at the individual-level
Keywords: social identity theory
partisanship
political communication
affective polarization

Affective polarization—hostility and aversion between rival political groups—is an increasingly salient feature of Western democratic politics. While scholars agree that this trend raises serious concerns for public life, its underlying drivers are still debated. This thesis enriches this line of research by clarifying some of the mechanisms shaping affective polarization at the individual level. My overarching research question is: What drives affective polarization at the individual level? I tackle this question through three distinct empirical studies that engage with separate aspect of this phenomenon. Study I leverages survey data to show that, among UK partisans, perceived conflict with their in-party on policy issues curbs affective polarization. Moving on to the digital sphere, Study II deploys computational methods to reveal the existence of affective biases in online political discussions between ideologically opposed Reddit users, and shows how the tone of their exchanges can both mitigate and worsen these patterns. Study III, finally, provides experimental evidence that only exposure to certain forms of online partisan messages have downstream consequences for affective polarization: those that explicitly threaten and devalue an individual’s own political party. Taken together, these findings reveal the drivers of affective polarization to be contingent on both situational and dispositional factors, including how ideologically aligned partisans are with their own political party, how their perceived political rivals engage with them in online conversations, and whether they are made to feel threatened by them.
Characterising the cardiac effects of dysregulated propionate metabolism using a mouse model of propionic acidaemia
Keywords: Organic anions
Excitation-contraction coupling
Cardiac dysfunction
Propionate
Organic acidaemia
Propionic acidaemia
Epigenetics

Propionate is a naturally-occurring monocarboxylate short-chain fatty acid in humans derived from the mitochondrial metabolism of multiple substrates. There is evidence for dysregulated propionate metabolism (and hence its accumulation), in common metabolic disorders, such as diabetes and obesity. However, the most extreme accumulation of propionate occurs in the inherited metabolic disease, propionic acidaemia (PA). Despite its rarity, PA is one of the commonest organic acidaemias. PA results from a defect in mitochondrial propionyl-CoA carboxylase, the rate-limiting step to propionate metabolism (as propionyl-CoA), resulting in the accumulation of propionate, and other related metabolites such as propionyl-carnitine and 2-methylcitrate. Interestingly, diastolic dysfunction, cardiomyopathy and arrhythmias account for significant morbidity and mortality in PA patients. However, the underlying mechanisms are yet to be fully elucidated.
The aim of this thesis was to characterise the effects of dysregulated propionate metabolism on the heart. This was primarily addressed by using a mouse model of PA (Pcca-/- A138T), in which the levels of propionate generated in vivo are sufficient to produce a metabolic signature of the human disease, but allows the animal to reach adulthood, thereby facilitating the study of cardiac physiology in vivo and in isolated cells.
Adventures on the isle of adolescence: forms of contemporary American girlhood
Keywords: Girls
Girlhood
Novel
Contemporary literature
Identity
Gender
American literature

This thesis examines how a revised version of the coming-of-age narrative has emerged in a range of contemporary novels, which offer feminist revisions of American girlhood through formal, thematic, and ideological departures from the traditional gendered narrative conventions of adolescence. Through this examination, this thesis argues that the American girl has been transformed from a flat aesthetic object in earlier iterations of the coming-of-age narrative, to a dynamic socio-political subject whose narrative centres upon the promotion of a range of feminist agendas in the contemporary novel.
The coming-of-age narrative has chiefly explored the development of adolescent boys, charting their ‘growing up’ into a world of masculine dominance and opportunity as they mature into men. In opposition to the expansive worlds of their male counterparts, girls’ coming-of-age narratives have routinely depicted an experience of ‘growing down’ into future womanhood, where the maturation from girl to woman charts a protagonist’s personal diminishment. In this story of the female coming-of-age experience, girls learn nothing more than how to acquiesce to the normative dictates governing gender identity.
However, this thesis argues that contemporary literature foregrounds new visions of American girlhood that explicitly destabilise the constricting conventions of the coming-of-age narrative. As a result of this generic reconfiguration, this thesis examines how the coming-of-age narrative has shifted from being an essentially conservative form that predominantly focused on the narratives of middle-class, white, heterosexual girls, to instead being used as a cultural vehicle to expand understandings of girlhood as an identity that is shaped by questions of gender, sexuality, race, disability, class, and religion in the post-1990 era.
Lewisian theism
Keywords: modal realism
modal metaphysics
Lewisian theism
philosophy of religion
classical theism
philosophical theology

Lewis’s modal realism is the view that possible worlds are maximal mereological sums of spatiotemporally connected individuals. Classical theism is the view that God is necessary, unitary, omnipotent, omniscient, omnibenevolent, simple, and the creator and sustainer of all existence. Lewisian theism is the conjunction of modal realism with classical theism. In my thesis by interrelated papers, I argue, firstly, that Lewisian theism is consistent, provided certain theoretical revisions are made to modal realism, and, secondly, that Lewisian theism has the resources to solve certain philosophico-theological problems. In the prologue, I introduce the thesis and expound Lewisian theism. In the first substantive paper, I argue that God’s necessity is incompatible with counterpart theory; but, in the second, I argue, contra the dominant view in the literature, that if we eschew counterpart theory for analysing God’s necessity, Lewisian theism is consistent. The third and fourth papers concern material adequacy; the third concerns the existence of evil worlds, wherein I argue that Lewisian theists can non-problematically deny the existence of such worlds; and the fourth concerns the existence of an empty world, wherein I argue that Lewisian theists can supply such a world. The fifth paper concerns Lewisian theism’s ability to solve a philosophico-theological problem; herein, I argue, firstly, that a valid version of the contingency argument against divine simplicity can be supplied (contra some philosophers), and secondly that Lewisian theism has the resources to render this argument unsound. The last paper contains an abductive argument for the existence of God from modal realism; I argue that the best way to account for the truths of advanced modal claims is to posit the existence of God.
Ordinary language philosophy: examining what we should say when
Keywords: projection
rule-following
Ludwig Wittgenstein
Stanley Cavell
J. L. Austin
ordinary language philosophy

This thesis takes its cue from J.L. Austin (‘A Plea for Excuses’): philosophy which proceeds from ordinary language (OLP) is an exercise in ‘examining what we should say when, and so why and what we should mean by it’ (P F E: 129). It argues that the method of OLP (The Method) is properly understood when we view language through a Cavellian lens. Linguistic competence emerges not as tacit knowledge of a system of strict rules, but as a kind of skill: a fluid ability to leverage one’s attunement to others in order to make oneself understood. In light of this, The Method ought to be understood as a self-conscious deployment of this skill, an invitation to project our words into novel contexts. Such an invitation is illuminating, because it asks us to attend, carefully and critically, to the world, and to follow out the holistic conceptual connections revealed by our projection of a word into a given context. Because this attention is careful and critical, OLP need not be conservative; neither need The Method precipitate us into a gross relativism. Indeed, a vision of language based on attunement offers a realistic, and deeply sensitive, picture of what is involved in responsibly negotiating our differences.
Carbonate precipitation during anoxic water-rock interaction, with implications for the formation of the Martian carbonates
Keywords: carbonate
fluid-rock interaction
geochemistry
Mars
olivine
Noachian

Despite over a Martian decade (20 years) of surface-based observations, reconciling Mars’ water- altered landscapes with a detailed reconstruction of its former atmosphere has remained problematic. Carbon dioxide is widely considered the main early atmospheric constituent based on expected outgassing behaviour and observed atmospheric isotope ratios, yet carbonate minerals — the expected sinks for this carbon — are only abundant in scarce isolated localities across the surface. While orbital spectroscopic investigations continue to yield an increasing inventory of these deposits, their relative rarity has prompted suggestions that the Noachian atmosphere was commonly characterised by low pCO2. However, without a thorough investigation of how exactly carbonates form under Mars-like conditions, their absence cannot be definitively linked to the absence of an atmosphere. To supply this key information, and to answer the more fundamental issue of carbonate precipitation mechanisms under anoxic, aqueous conditions, this thesis examines the controls on Fe(II)-carbonate precipitation. Anoxic experiments were conducted that varied initial pH, rock:water ratio, and pCO2. These were run with the minerals fayalite, a combination of fayalite/forsterite (Chapter 3), followed by rock common to Mars (basalt; Chapter 4). In these experiments no substantive Fe(II)-carbonate precipitation occurred despite significant supersaturation with respect to siderite. Reaction path models indicate Fe(II)-carbonate supersaturation thresholds would have been commonly met in low rock:water ratio systems within the subsurface as opposed to high-pCO2, high water-rock systems exposed at the near-surface. This suggests that the rarity of Martian carbonates may be partly controlled by a lack of deep crustal exposures, rather than insufficient atmospheric pCO2. Later, at hydrothermal temperatures of 75 °C (Chapter 5), siderite formed in appreciable quantities as rhombs and hexagonal platelets. This is consistent with carbonate formation in a warmer, sheltered subsurface. Together, the experiments within this thesis support wider orbital data by other researchers suggesting that carbonates may comprise a large component of the deep crust, potentially representing a geologically significant carbon sink and offering a suggested fate for a once substantial (~1 bar) atmosphere.
Realising complex quantum states of matter via symmetries and heating
Keywords: Superconductivity
Long-Range Order
Strongly Correlated Systems, Driven Quantum Systems, Open Quantum Systems, Symmetry, Superconductivity, Quantum Engineering, Off-Diagonal Long-Range Order
Symmetry
Open Quantum Systems
Driven Quantum Systems

Identifying mechanisms which can guide many-body quantum systems into regimes where properties such as entanglement and long-range coherence are manifest is a fundamental goal for those working in the field of strongly correlated systems. With this comes the potential to realise and exploit states of matter such as superconductors and superfluids, where quantum behaviour is observable at the macroscopic level.
In this thesis we study how symmetries and heating can, counterintuively, be used to realise phases of matter with such desirable properties. We prove how heating a many-body system whilst preserving certain symmetries - such as those of the special unitary group - result in the formation of maximum entropy states which are confined to a subspace of the total Hilbert space and are capable of possessing finite, completely uniform off-diagonal correlations. This mechanism is termed heating-induced order and is independent of any microscopic details.
We use the Hubbard model as a central example where this mechanism can be observed. Heating is introduced to the system via periodic driving or local dissipation and we study the various ordered steady states which emerge in this setup. We discuss the applicability of this mechanism to the thermodynamic limit and its relevance to recent solid-state experiments observing photo-induced superconductivity in irradiated compounds.
We then show how, in an open quantum system, the satisfaction of a set of simple symmetry-based conditions guarantees an absence of stationarity and the formation of coherent oscillations in the long-time limit. We prove how this result subsumes and goes beyond the established notion of a Decoherence Free Subspace. When these conditions are satisfied in the presence of heating-induced order we observe the formation of an entangled, correlated state undergoing identical limit cycles at all positions in space. This leads us to formulate a novel process for quantum synchronisation which is based on the combination of these symmetry-based conditions and the mechanism of heating-induced order.
What mediates the effects of wealth on children's vocabulary developmental trajectories in Ethiopia? A longitudinal analysis
Keywords: vocabulary development
child poverty
mediated wealth effects
vocabulary assessment
Ethiopia
developmental trajectories
educational measurement
cross-cultural assessment
wealth effects
Rasch model
models of child development

This D.Phil study is motivated by gaps in educational research in low-income countries. First, it uses a child developmental, rather than economic, model to investigate how the timing of poverty shapes children’s vocabulary trajectories and the mediational pathways through which poverty influences growth at different stages of childhood. Second, it investigates the reliability and validity of the measure used to assess vocabulary, addressing inter-cultural issues that have not been dealt with in the literature and challenging some of the assumptions underlying the use of psychometric approaches in low-income countries. Data from a sample of 1,321 children in Ethiopia, who took part in the Young Lives longitudinal study at ages five, eight, twelve and 15 years, were analysed. The Peabody Picture Vocabulary Test (PPVT) was used to measure vocabulary ability. A composite wealth index was used to measure living standards.
The psychometric properties of the PPVT were analysed within a Rasch measurement model. The test was screened for unidimensionality, item targeting, differential item functioning and scale stability. To compare the scores obtained at different time points, scores from the repeated test were calibrated onto a single metric using a test equating procedure. The Rasch estimates were obtained by anchoring the scores on the most stable items within each of respective language groups: Amharic, Oromifa and Tigrinya.
A multilevel model for change approach was used to estimate individual growth trajectories. On average, children in the highest wealth quintile outperformed children in the lowest quintile. The difference in the mean growth trajectories between top and bottom quintiles followed a constant path, except in Amharic in which the average gap narrowed by 0.47 SD. Initial wealth, measured at one year of age, predicted onset ability at five years for all language groups, and the growth rate between 5-15 years in Amharic. Changes in wealth did not further help to explain the variance in the intercept or the slope.
The analysis was extended to account for the factors that mediate the poverty-growth relationship. The results showed that 0-10% of the wealth effect on onset ability was mediated by the height-for age z-score, a measure of nutrition. Mothers’ education mediated 1-8% of the wealth effect. Preschool participation mediated 6-14%. The findings reinforce existing literature about the importance of these factors in mitigating the effects of poverty on children’s vocabulary development, particularly in early childhood. The study further highlights that expanding this knowledge base requires an in-depth understanding of the contexts in which children develop and learn, drawing on insights from substantive theories and local understandings of development and learning.
PDE based models of electric field sensors and their corresponding inverse problems
Keywords: electric field sensing
capacitance
sensors
electrical impedance tomography
shunt model
electrical capacitance tomography

This thesis is concerned with the forward and inverse problems associated with Electrical Capacitance Tomography (ECT) and Electrical Impedance Tomography (EIT). We collectively refer to these paradigms, and other associated modalities, as Electric Field Sensing (EFS). Common to all EFS modalities is the aim to determine the conductivity and permittivity of the material inside a volume from measurements of the electric potential and electric flux taken on the boundary of the volume. EFS modalities have many applications in industrial processes and medical diagnostics due mainly to the non-invasive, non-ionising, and non-destructive property of electric field measurements.
For each application the choice of electrode configuration and sensor input are critical: the shape of the generated electric field and the measurement sensitivity and material specificity are dependent on these choices. We are particularly motivated to study planar configurations of electrodes with time-dependent voltage impulses applied sequentially to different subsets of the electrodes.
We derive five PDE models that describe the electric field in either the frequency or the time domain. In particular, we propose a novel choice of boundary conditions, determined by a coupled ODE, to model additional circuit components and parasitic capacitances inherent in all EFS sensors. For each model, we prove existence and uniqueness results. We also discuss the numerical solution of each model using the Finite Element Method (FEM).
We then consider the inverse problems associated to each of the five models. We detail four, practically inspired, measurement paradigms and prove equivalence by explicitly constructing bijections between them. Our unified approach of combining sequential measurements can be applied to each of the five models. Most notably, we prove the equivalence between sequential measurements taken on two electrodes with measurements taken concurrently on all electrodes. We also discuss the partial data case where not all electrode pairs are sampled.
Finally, in the case of the partial data, we discuss novel methods for estimating the missing data using known measurements of a closely related parameter distribution: the benefit being reconstruction algorithms developed for the full data problem can then be applied to the partial data case.
High-order numerical methods for scattering problems
Keywords: numerical analysis
integral equations
scattering theory
fast direct solvers

Scattering problems are ubiquitous in scientific and engineering applications. These problems can often be straightforwardly modeled using relatively simple linear partial differential equations, such as the Helmholtz equation. The numerical solution of these equations, however, can be challenging due to several features of the problem, such as ill-conditioning, unbounded domains, corner singularities, and oscillatory solutions. In this thesis we present novel numerical methods for the efficient handling of some of these challenges.
We first consider the case of homogeneous scattering on domains with corners and introduce a new solver in this regime, based on results in the rational approximation theory literature. The solver uses an exponentially clustered sum of dipoles to resolve the singularities in the solution and a simple expansion to resolve the smooth part. We show that the convergence is root-exponential with respect to the number of degrees of freedom and illustrate the behavior of the solver in several numerical experiments.
We next turn our attention to the case of inhomogeneous scattering and present a new solver for the Lippmann–Schwinger equation, an integral equation reformulation of the problem. The new solver is based on the hierarchically block separable matrix format and exploits the geometry of the discretization and problem for accelerated inversion. The solver is shown to be effective both as a direct solver and preconditioner in a number of numerical experiments.
For our last contribution we consider broadband applications in homogeneous scattering. We present a new technique for accelerating existing direct solvers in this regime. The technique works by computing basis matrices for all of the low-rank blocks in a rank-structured matrix format and leverages the observation that the resulting ranks are often comparable to those at just the highest frequency. Again, the viability of the method is illustrated in several numerical experiments.