VictorJuiz/thesis huggingface dataset:
Magnetic quantum oscillations in organic metals based on the molecule Bis(ethylenedithio)tetrathiafulvalene

ET charge transfer salts (where ET is bis(ethylenedithio)- tetrathiafulvalene)
have relatively simple quasi two-dimensional Fermi surface topologies, making them ideal for the study of the relationship between bandstructure and properties such as superconductivity. Experimental studies of the Fermi surface areas and associated effective masses have been carried out using the Shubnikov-de Haas (SdH) and de Haas-van Alphen (dHvA) effects. By comparing the experimental results to theoretical bandstructure calculations the strength of many body interactions has been estimated.
High pressure magnetotransport experiments have been carried out on the superconductor κ-ET2Cu(NCS)2. The observation of SdH and magnetic breakdown oscillations has allowed the pressure dependences of the Fermi surface topology and effective masses to be deduced and compared with simultaneous measurements of the superconducting critical temperature. The data strongly suggest that the enhancement of the effective mass and the superconducting behaviour are directly connected. The results are compared with several current theories of superconductivity.
The dHvA effect has been used to probe the superconducting mixed state of κ-ET2Cu(NCS)2. A recent model of the superconducting mixed state is applied to the experimental data in an attempt to determine the value and symmetry of the superconducting energy gap.
SdH measurements up to 30 T have been used to study spin densitywave formation in α-ET2KHg(SCN)4, and the reasons why a very slight increase of the unit cell volume (i.e. replacing the K in α-ET2KHg(SCN)4 by NH4) stabilises a superconducting state. Galvanomagnetic techniques have been used to measure the quasi onedimensional Fermi surface orientation below the spin-density-wave transition, and to accurately determine the shape of the quasi twodimensional Fermi surface above it.
The application of pressure has been used to gradually reduce the onset temperature of a metal-insulator transition and to eventually stabilise a superconducting state in ET3Cl22H2O. The bandstructure of ET3C122H2O has been investigated using the SdH effect whilst hydrostatic pressure has been used to pass through the superconducting part of the phase diagram.

Advisor: Singleton, J
Genetics of nonsense suppressors in yeast

This thesis is a genetic study of the cytoplasmically- inherited determinant [psi] of Saccharomyces cerevisiae . [psi] is a potentiator of ochre suppression. The molecular basis of [psi] was investigated using mutagenesis as a probe. The psi+ phenotype (efficient suppression) can be mutated to psi- phenotype (loss of suppression) by ultra-violet light (UV) and nitrosoguanidine (NTG) . The UV-induced mutation was a single-hit event and the pre-mutational lesion was partly photoreactivable . Repair or expression of UV-induced mutation to the [psi] determinant was under the same genetic control as for nuclear mutation. It was concluded that [psi] has a DNA genome. The 'extrachromosomal mutagens' thymidylate starvation, 5-fluorouracil, manganese chloride and cycloheximide failed to induce psi- mutants whilst guanidine hydrochloride, dimethyl sulphoxide and potassium chloride were shown to induce this mutation at frequencies up to 100%. Several other physical and chemical agents caused a high frequency of loss of the psi+ phenotype.
A new class of recessive nuclear mutation (pnm) was shown to cause a loss of the psi+ phenotype. A simple comple- mentation test was devised to distinguish them from cytoplasmic psi- mutants. The dominant PNM- mutation was shown not to cause a physical loss of the [psi] genome. Two mutants with a modified PNM- phenotype were analysed. Attempts to demon- strate genetically the involvement of [psi] with the 80S ribosome were unsuccessful. The psi+ phenotype was conclusively demonstrated to be inherited independently' of the nucleus using a 'heterokaryon test'. Two models for the [psi] phenomena were proposed; one postulating the presence of a DMA 'plasmid' and one postulating the involvement of a stable, self-perpetuating metabolic state.

Advisor: Cox, B
Mathematical modelling, forecasting and telemonitoring of mood in bipolar disorder

This study applies statistical models to mood in patients with bipolar disorder. Three analyses of telemonitored mood data are reported, each corresponding to a journal paper by the author. The first analysis reveals that patients whose sleep varies in quality tend to return mood ratings more sporadically than those with less variable sleep quality. The second analysis finds that forecasting depression with weekly data is not feasible using weekly mood ratings. A third analysis shows that depression time series cannot be distinguished from their linear surrogates, and that nonlinear forecasting methods are no more accurate than linear methods in forecasting mood. An additional contribution is the development of a new k-nearest neighbour forecasting algorithm which is evaluated on the mood data and other time series. Further work is proposed on more frequently sampled data and on system identification. Finally, it is suggested that observational data should be combined with models of brain function, and that more work is needed on theoretical explanations for mental illnesses.

Keywords: time series analysis
mood variability
bipolar disorder
psychiatry
public healthcare
Advisor: Howell, P
Little, M
Yves Bonnefoy: the performative and the negative

This thesis examines Bonnefoy’s cultivation of the performative aspects of the poetic act in his later collections of poetry. It investigates the poet’s use of the theatrical structures of poetic performance, their temporal and spatial dynamics, to deconstruct conceptual or representative modes of thought. It examines how Bonnefoy uses apostrophes to insentient phenomena and addresses to an unidentified other in his attempts to open language up to the finitude and sharing of existence. Working within language, against language, the poet cultivates what he describes as ‘un savoir, tout négatif et instable qu’il soit, que je puis peut-être nommer la vérité de la parole’.
The first chapter of this thesis investigates how the image of the ephemeral flame becomes a model for a finite poetic performance in ‘La Terre’. The second chapter scrutinises how Bonnefoy makes the signifying function of language ‘passive’ to the inappropriable excess of material presence in Début et fin de la neige. The third chapter, analysing ‘La Voix lointaine’, explores how Bonnefoy dramatises the experience of self-presence as the act of listening to a distant voice. The fourth chapter, investigating the relationship between finitude and form in ‘L’Heure présente’, analyses how the dissolution of form gives rise to a form that is always à venir, a dynamic, ‘un possible’.

Keywords: finitude
performance
twentieth-century French thought
Yves Bonnefoy
negativity
twenty-first-century French poetry
philosophy
Jean-Luc Nancy
performativity
poetics
twentieth-century French poetry
Advisor: Sheringham, M
Signatures of Gaussian processes and SLE curves 

This thesis contains three main results.
The first result states that, outside a slim set associated with a Gaussian process with long time memory, paths can be canonically enhanced to geometric rough paths. This allows us to apply the powerful Universal Limit Theorem in rough path theory to study the quasi-sure properties of the solutions of stochastic differential equations driven by Gaussian processes. The key idea is to use a norm, invented by B. Hambly and T.Lyons, which dominates the p-variation distance and the fact that the roughness of a Gaussian sample path is evenly distributed over time.
The second result is the almost-sure uniqueness of the signatures of SLE kappa curves for kappa less than or equal to 4. We prove this by first expressing the Fourier transform of the winding angle of the SLE curve in terms of its signature. This formula also gives us a relation between the expected signature and the n-point functions studied in the SLE and Statistical Physics literature. It is important that the Chordal SLE measure in D is supported on simple curves from -1 to 1 for kappa between 0 and 4, and hence the image of the curve determines the curve up to reparametrisation.
The third result is a formula for the expected signature of Gaussian processes generated by strictly regular kernels. The idea is to approximate the expected signature of this class of processes by the expected signature of their piecewise linear approximations. This reduces the problem to computing the moments of Gaussian random variables, which can be done using Wick’s formula.

Keywords: Chen series
Gaussian processes
SLE curves
Rough path theory
Quasi-sure analysis
Advisor: Qian, Z
The economic development of the Rhine river basin in the Roman period (30 BC - AD 406)

The economic development of frontier regions has been neglected in the study of the Roman economy. Traditional core/periphery models suggest that frontiers were marginal zones dependent on a wealthy Mediterranean core, and this view has dominated scholarship for more than thirty years. In light of recent work on the Roman economy, it is clear that many old models need to be reappraised; this thesis examines the economic development of frontiers through the case study of the Rhine River Basin. This region formed one of Rome’s northern frontiers for more than 400 years and has a rich tradition of detailed archaeological and historical research. Using data from the Rhine frontier, this thesis re-examines the nature of frontier economies, arguing that they were dynamic, versatile, and complex rather than subaltern and undeveloped. A new model, based in the analytic framework of economic geography, is suggested as a replacement in order to appreciate the realities and potential of frontier economies.

Keywords: Roman economy
Rhine River
Roman archaeology
Roman Germany
Roman history
Roman frontiers
Advisor: Wilson, A
United States defence bases in the United Kingdom

The main concerns of the study, covering the years 1945-84, are arrangements that have been made for the use of military bases in the United Kingdom by United States forces. The subject is examined within a chronological framework.
The development of the United States military presence is traced, from the earliest Joint Chiefs of Staff plans in 1945 and the Spaatz- Tedder agreement in 1946, which gave the United States permission to deploy certain forces in the United Kingdom in time of emergency. The 1948 Berlin Crisis led to the arrival of bombers in East Anglia which was the first major post-war deployment of United States forces to Britain. It was stated that it would be for a period of temporary duty. In fact the bases have remained from that day to this, though their number and types have varied over time.
The Korean War proved to be the next major turning point. It increased demands upon the Attlee government for an agreement defining the conditions of use of United States bases in the United Kingdom. The subsequent Truman- Attlee, and later Truman-Churchill, meetings resulted in the key phrase: the use of bases would be 'a matter for joint decision ... in the light of circumstances prevailing at the time.' Different interpretations have been placed on these words at different times. The years 1950-57 saw a consolidation of the United States military presence, with Britain's importance as an intelligence base also growing.
The dawning of the missile age symbolised by the first Soviet earth satellite in 1957, the agreement in the same year to deploy Thor missiles, and the deployment of Polaris to Holy Loch in 1960, raised questions regarding the adequacy of the earlier agreements on the conditions of use. This factor, alongside the development of a distinct European identity of which Britain has become a part, has led to a questioning of American hegemony within NATO. The arrival of cruise missiles in 1983 gave added urgency to the debate. Whilst it may be generally recognized that the bases make a substantial contribution to the United Kingdom's defences, the need for clarification of the uses to which the bases can be put by United States forces remains.
The roles played by the transcriptional regulators PPARalpha, HIF-1alpha and SIRT1 in the control of cardiac metabolism

The failing heart is characterised by altered energy substrate metabolism, which is a potential target for the development of new heart failure treatments. Transcriptional regulatory proteins orchestrate long-term control of cardiac metabolism by altering gene expression patterns. Thus, these proteins may be viable targets for such metabolic therapies. The work in this thesis aimed to increase understanding of the roles and interactions of three important transcriptional regulators, PPARα, HIF-1α and SIRT1 in the heart, using a combination of animal and cell culture models. Wild type (controls) and PPARα knockout mice were fasted for 24 hours, with PPARα shown to be non-essential for mediating metabolic flexibility through pyruvate dehydrogenase (PDH) down-regulation. Aged male and female PPARα knockout mice had increased cardiac PDH flux in the fed and fasted states relative to controls, indicating a role for PPARα in aging-associated metabolic changes. Subsequently, the HL-1 cardiomyocyte cell line was characterised as an in vitro model of cardiac metabolism, with studies of hypoxia and hypoxia mimetic treatment demonstrating mitochondrial metabolic changes of a HIF-1α-dependent or independent nature. Male Wistar rats were treated with nicotinamide, to investigate its ability to modulate cardiac SIRT1 activity through increasing tissue NAD levels. Nicotinamide treatment altered cardiac metabolism by decreasing PDH activity and modulating mitochondrial metabolic pathways, as well as increasing cardiac SIRT1 activity after 8 weeks of treatment. To assess the interactions between SIRT1, PPARα and HIF-1α, rats were subjected to fasting, high fat feeding or hypoxia treatments. Cardiac SIRT1 activity was respectively increased and decreased by fasting and high fat feeding treatments in rats, and hypoxic exposure decreased SIRT1 activity, demonstrating cross talk between the activities of PPARα, HIF-1α and SIRT1 in the heart. The results presented here increase knowledge of cardiac transcriptional regulation, which is important for our understanding of how manipulating cardiac metabolism may enable the development of therapies to improve energy metabolism in cardiac disease states.

Keywords: Cardiac metabolism
Advisor: Carr, C
Tyler, D
Graphical Gaussian models with symmetries

This thesis is concerned with graphical Gaussian models with equality constraints on the concentration or partial correlation matrix introduced by Højsgaard and Lauritzen (2008) as RCON and RCOR models. The models can be represented by vertex and edge coloured graphs G = (V,ε), where parameters associated with equally coloured vertices or edges are restricted to being identical.
In the first part of this thesis we study the problem of estimability of a non-zero model mean μ if the covariance structure Σ is restricted to satisfy the constraints of an RCON or RCOR model but is otherwise unknown. Exploiting results in Kruskal (1968), we obtain a characterisation of suitable linear spaces Ω such that if Σ is restricted as above, the maximum likelihood estimator μ(with circumflex) and the least squares estimator μ* of μ coincide for μ ∈ Ω, thus allowing μ and Σ to be estimated independently. For the special case of Ω being specified by equality relations among the entries of μ according to a partition M of the model variables V, our characterisation translates into a necessary and sufficient regularity condition on M and (V,ε).
In the second part we address model selection of RCON and RCOR models. Due to the large number of models, we study the structure of four model classes lying strictly within the sets of RCON and RCOR models, each of which is defined by desirable statistical properties corresponding to colouring regularity conditions. Two of these appear in Højsgaard and Lauritzen (2008), while the other two arise from the regularity condition ensuring equality of estimators μ(with circumflex) = μ* we find in the first part. We show each of the colouring classes to form complete lattices, which qualifies the corresponding model spaces for an Edwards-Havránek model selection procedure (Edwards and Havránek, 1987). We develop a coresponding algorithm for one of the model classes and give an algorithm for a systematic search in accordance with the Edwards-Havránek principles for a second class. Both are applied to data sets previously analysed in the literature, with very encouraging performances.

Keywords: statistics
symmetry
Gaussian distribution
graphical models
Advisor: Lauritzen, S
Quantum materials explored by neutron scattering

This thesis describes neutron scattering experiments on strongly correlated systems exhibiting a range of emergent phenomena: antiferromagnetism, charge order, superconductivity and multiferroicity. I have examined the La_{2}CoO_{4} compound which is a Mott insulator and orders antiferromagnetically near room temperature. The La_{2}CoO_{4} sample was studied using spherical neutron polarimetry and I present magnetic structure models to describe the two antiferromagnetic phases of the compound. Furthermore, the magnetic fluctuations have been investigated using neutron time-of-flight technique. This has allowed us to extract the dominant exchange interactions in the system. More interestingly, the work on La_{2}CoO_{4} presented in this thesis provides a basis for the experimental evidence of an hourglass dispersion in La_{5/3}Sr_{1/3}CoO_{4}, previously only observed in the copper oxide based superconductors. This dispersion has been understood in terms of a stripe ordered magnetic phase and was found to be well described by a linear spin-wave model.
Neutron scattering experiments were also carried out on the new iron-based high-temperature superconductors, FeSe_{x}Te_{1−x}. A range of compositions were studied, including both antiferromagnetically ordered and superconducting. Below the superconducting phase transition temperature, a spin resonance mode was found centred on the antiferromagnetic wavevector. This is an important feature shared by many unconventional superconductors. The spin resonance intensity was found to reflect the order parameter of the superconducting state. Polarised inelastic neutron scattering experiments have revealed a small anisotropy between the in-plane and out-of-plane magnetic fluctuations at the resonance. This anisotropy cannot be readily explained by the usual anisotropic terms in the Hamiltonian. This could be evidence of new physics in the FeSe_{x}Te_{1−x} superconductors.
Finally, I have studied CuO – a high-temperature multiferroic. Analysis of polarised neutron diffraction experiments shows that the magnetic domain population can be varied using an externally applied electric field. This unambiguously demonstrates coupling between the magnetic and ferroelectric degrees of freedom. Using representation analysis I derive the incommensurate magnetic structure in the multiferroic phase. The origin of the magnetoelectric coupling is consistent with models based on the inverse Dzyaloshinskii-Moriya interaction.

Keywords: magnetism
superconductivity
neutrons - scattering
Advisor: Boothroyd, AT
TCR signalling in response to affinity stimulation

T cells are an essential part of the adaptive immune system and protect the body from intracellular infections. The specificity with which αßTCR-bearing T cells recognize cognate antigen presented on MHC molecules is paramount to maintaining the balance between mounting effector functions against pathogens and establishing peripheral tolerance to self. The mechanism by which T cells translate qualitative differences in TCR:pMHC binding to sensitive proximal signalling events which ultimately result in specific Tcell effector responses to infected cells but not to self is mostly unknown.
To address how T cell signalling responds to qualitative differences in TCR triggering by pMHC, I established a system of stimulating T cells bearing the 1G4 TCR specifically in vitro with a panel of four NY-ESO-1156-165 peptide variant MHC tetramers. Single amino acid substitutions to the NY-ESO-1156-165 peptide conferred a maximum 35-fold difference in the monomeric affinity for the 1G4 TCR. The system allows the highly controlled investigation of very rapid TCR proximal signalling events simultaneously and quantitatively using flow cytometry. Stimulations with pMHC tetramers showed rapid sensitive sequential signalling responses which were able to confer ligand discrimination. Very early signalling events such as CD3ζ phosphorylation showed analogue responses to the different affinity pMHC tetramers. Later signalling events including phospho-ERK showed a distinct on/off switch-like response. The amplitude of the very early analogue signalling responses determined the extent of later digital ERK signals. This indicates that a certain analogue signalling threshold must be passed to result in T cell activation.
The thymocyte protein Themis has been shown proximal TCR signalling to modulate thymocyte selection thresholds. Its deletion results in profound defects in positive thymocyte selection. Themis locates to the LAT signalosome of the TCR signalling cascade via Grb2, yet its molecular function is unknown. Employing the system I established, I demonstrate that Themis-k/d cells show increased levels of CD3z-chain phosphorylation, phospho-ERK signalling and signal-induced apoptosis which was independent of the ERK signal. This shows that Themis is a global attenuator of proximal TCR signalling. We are currently investigating possible associations of Themis to proteins phosphastases such as SHP-1 which could attenuate TCR proximal protein tyrosine signalling events.

Keywords: T cell receptor
Themis
pMHC tetramers
T cells
affinity signalling
TCR
Advisor: Acuto, O
A causal approach to transitivity

The present thesis presents a causal approach to transitivity and proposes a model of transitivity based on the view that a single event is a single ‘causal impact’, which consists of a single causation and a single effect. It defines semantic intransitivity as events where the effect is borne by and expressed through the actor and semantic transitivity as events where the effect is borne by and expressed through the patient. It finds evidence for this definition in the phenomenon of ‘selective specification’ of action or result by verbs with actor and patient. Furthermore, it proposes that the verb eat has dual event structures, intransitive and transitive, and uses a Web data test to test and confirm this hypothesis.

Keywords: transitivity
object omission
event individuation
Web data
causality
Advisor: Fellerer, J