VictorJuiz/thesis huggingface dataset:
Dynamics of driven colloidal systems in one-dimensional potential energy landscapes

The dynamics of colloidal particles driven over optical potential energy landscapes is studied. Experiments are conducted using colloids driven by solvent flow or piezo-stage, optical tweezers, magnetic fields, and video-microscopy. Firstly, the properties of optical traps and potential energy landscapes are determined using driven colloidal particles and clusters. The trap stiffness and potential depth of single Gaussian traps are measured directly. It is shown that the nature of optical potential energy landscapes may be fully engineered and predicted using a sum of single Gaussian potentials. Next, the motion of colloidal particles driven by a constant force over a periodic optical potential energy landscape is considered. The average particle velocity is found as a function of the driving velocity, and the wavelength of the optical potential energy landscape, which is found to be sinusoidal at small trap spacings. The critical driving velocity required for a particle to move across the landscape is determined as a function of the wavelength. Brownian motion is found to have a significant effect on the critical driving velocity, but a negligible effect at high driving velocity. Subsequently, the dynamic mode locking caused by adding a modulation to the driving force is studied. This synchronisation manifests as a `Devil's staircase' in the average particle velocity as a function of driving velocity. The amplitude and frequency dependence of the mode locked steps are studied. Furthermore, particle trajectories are examined, and phase portraits show locked (unlocked) states as closed (open) loops in phase space. A state diagram of mode locked steps is constructed. Finally, driven systems of magnetically interacting colloidal particles are examined in potential energy landscapes. The critical driving velocity of a chain of coupled particles driven by a constant force is found to depend strongly on the chain length and the magnetic field. Secondly, a mobile density wave (kink) in an optically pinned chain of coupled particles is exposed to a constant and modulated drive. The kink is found to behave as a quasi-particle, exhibiting analogous dynamic mode locking behaviour to the single particle case. Finally, the mode locking of a finite mobile chain is considered, and found to be affected by the chain flexibility, which is a function of the magnetic field.

Keywords: driven
colloidal
potential energy landscape
Advisor: Dullens, RPA
The influence of donor body mass index on human pancreatic islet function, structure and islet transplant outcome

Background: Pancreatic islet transplantation for type-1 diabetes has resulted in considerable success over the past decade. However, the worldwide shortage of pancreatic donors remains a major challenge. In an attempt to expand the donor pool, pancreases from obese organs donors (>30 kg/m²) are now routinely offered to islet transplantation in the UK. In addition, it has been suggested that pancreases from donors with early type-2 diabetes mellitus may also be suitable. However, for both these donor groups, although high islet yields (IEQ) may be obtained, it is unclear whether these islets function optimally. An additional approach to the donor shortage is to minimise the number of donors required per islet recipient. One strategy to achieve this is to use different pharmacological agents to enhance post-transplant islet function.
Aims: The aims of this thesis were fourfold; 1) To determine whether islets isolated from high BMI donors function normally in vitro and in vivo; 2) To establish why islet yields are higher from obese donors; 3) To determine whether islets from donors with type-2 diabetes are suitable for islet transplantation; 4) To investigate whether glucagon-like peptide 1 receptor agonist therapy improves post-transplant islet graft function.
Results: Stimulated insulin and glucagon secretion, and markers of mitochondrial function (intra-islet ATP content and mitochondrial copy number) were compared in islets isolated from obese (BMI>30kg/m²; n= 27) and non-obese (BMI<28kg/m²; n=25) donors. No differences in secretory function or intra-islet ATP were observed between the two groups. Pancreatic lipid and intra-islet triglyceride concentrations were higher in the obese group. In vivo clinical outcomes of patients transplanted in Oxford and a larger cohort (n=35) in Edmonton, Canada with islets from obese or non-obese donors showed no differences in post-transplant outcomes. Improved islet yields were shown to be a result of improved islet recovery of larger islets, in obese donors. Abnormal insulin and glucagon secretory responses were observed in islets from type-2 diabetic subjects (n=6) and islet amyloid content was significantly higher in diabetes. The glucagon-like peptide 1 receptor agonist, exenatide, administered for 20 weeks, significantly improved graft function in patients whom islet function was impaired.
Conclusion: The high lipid environment of islets isolated from donors with high BMI appears not to be deleterious to their function either in vitro or when transplanted, supporting the use of islets from high BMI donors for clinical islet transplantation. However, islet dysfunction and pathological changes indicate that islets from type-2 diabetic donors are unsuitable. Therapeutic options such as exenatide, improve transplanted islet viability and function, and could have a significant role in the future of beta-cell replacement therapy for type-1 diabetes.

Keywords: transplantation
type 1 diabetes
obesity
islet cell
diabetes
BMI
Advisor: Johnson, P
Rorsman, P
Electronic trading in the foreign exchange spot market

During the past 30 years, the proliferation of electronic trading has catalysed profound structural change in the global foreign exchange (FX) spot market. Today, more than 60% of the market's volume occurs via electronic trading platforms, which provide traders with round-the-clock market access from anywhere in the world. Such platforms offer several practical benefits that have encouraged market participation from a broad new class of financial institutions and have thereby spurred market growth.
The most widely used electronic trading platforms in the FX spot market incorporate several features that differentiate them from those used in other financial markets. These features raise many important questions about order flow, market state, price formation, trader behaviour, and volatility. Despite the enormous trade volumes that such platforms facilitate, these questions have received almost no attention to date.
In this thesis, we study a recent, high-quality data set from a large electronic trading platform in the FX spot market in order to investigate several aspects of trading via this mechanism. We calculate a wide range of statistics regarding order flow and market state, and we highlight how our findings contrast to those reported by empirical studies of electronic trading platforms in other markets. We study the autocorrelation properties of returns, absolute returns, and order flow, and we investigate the extent to which the market's organization impacts price formation. We also introduce a model designed to reproduce the most important properties of trading via such a platform. We derive several results regarding the model's temporal evolution, and we simulate the model to investigate how the interactions between individual traders influence volatility. We conclude that electronic trading platforms in the FX spot market retain many desirable features of centralized markets while providing traders with explicit control over their personal trading partnerships.

Keywords: Electronic trading
foreign exchange market
price formation
market microstructure
quasi-centralized liquidity
limit order book
Advisor: Porter, MA
Howison, S
The experience of four famines in the NWPandO (1837-8, 1860-1, 1868-9, 1896-7)

This study focuses on four famines (1837-8,1860-1,1868-9,1896-7) that afflicted the North Western Provinces and Awadh, the present day Uttar Pradesh, but no longer including the hill districts.
This study looks at the discourse, responses to and perceptions of famines by certain groups in NWPandO society. The study argues that while famines were disasters for some sections of affected people, they proved significantly beneficial to others. It argues that long- standing social, economic and political imbalances caused the impact of famines to fall on already vulnerable and poor sections of society, while the rich and powerful derived important political, economic, social and religious benefits. The policies abetting these and the mechanisms by which these benefits were derived are examined.
Besides poverty, fragmentation and breaking up of community and family structures and more importantly, lack of political accessibility and inadequate political representation added to the woes of the victims. The perceptions, discourse and responses of famine victims have been detailed.
At the same time the use of power and political accessibility to derive important gains- political, economic and religious is emphasized. The activities of beneficiary groups extended famines in space and time. Their perception and responses to famine have been highlighted, and the varying fortunes of victims and beneficiaries compared and contrasted.
Relief policy largely failed to alleviate even immediate famine distress. A generous and liberal relief policy taking into account the needs and cultural susceptibilities of the affected people was required. But such a policy was not evolved even till the end of the nineteenth century as strategic, bureaucratic, cultural and ideological priorities took precedence over the sufferings of the needy. Officials largely ignored or failed to take into account that relief was being exploited for important economic, political and religious gains.
The issues and problems discussed in the present thesis are relevant for modern times, especially in the case of India. If modern- day relief policies remedy these shortcomings and adopt realistic long-term measures to redress socio- economic and political imbalances that afflict society in India, then the negative impact of famines can be contained.

Advisor: Powell, A
Risk factors for specific subtypes of ischaemic stroke

Ischaemic stroke is a complex disorder with many different aetiologies, but previous studies of stroke often did not differentiate aetiological subtypes of ischaemic stroke. However, different stroke subtypes may have different risk factors, and to target preventive treatments more effectively, we need to understand these associations.
I studied the association of established vascular risk factors with different aetiological stroke subtypes in population-based cohorts of stroke patients. I studied Diffusion Weighted Magnetic Resonance Imaging (DWI) in patients with subacute minor stroke and TIA to determine whether DWI may be a useful addition to the management of such patients, and whether it may be a useful tool in future epidemiological studies of stroke. To determine whether carotid anatomy may be a risk factor for large vessel atheroma I studied angiographical data from the European Carotid Surgery Trial.
My main findings are that the prevalence of risk factors differs between stroke subtypes. It also differs between hospitalised and non-hospitalised patients, highlighting that risk factor studies should be performed in population-based cohorts. Analysis of family history data suggests that future genetic studies may best be targeted at non-cardioembolic stroke and at younger patients, and that genetic studies of hypertension may help to unravel some of the genetic factors contributing to stroke risk.
DWI is sensitive in subacute minor stroke, and inter- and intra-observer reproducibility are high. DWI frequently adds useful information and may influence patient management. More widespread use of DWI in patients with subacute stroke and TIA should be considered, and DWI may also be a useful tool in future epidemiological studies of stroke.
Carotid anatomy varies considerably between individuals, is very asymmetrical within individuals, and it differs between men and women. These findings may partly explain differences in plaque development between individuals, asymmetrical plaque formation within individuals, and sex differences in the distribution of carotid plaque and in the prevalence of carotid atheroma in the general population. Carotid anatomy may be a risk factor for local plaque development. Although not amenable to treatment, knowing which anatomical configuration is associated with atheroma formation could help to identify high-risk individuals in whom other risk factors should be treated aggressively.

Advisor: Rothwell, P
Poetics of the urban, poetics of the self: a comparative study of selected works by Jorge Luis Borges and Jacques Réda

This thesis explores the poetic representation of Buenos Aires and Paris in selected works by Jorge Luis Borges and Jacques Réda respectively. Its primary aim is to analyse the relational phenomenon between the construction of these poets' personal maps of the city and the concomitant formation of the poetic self. The principal point of departure is Jacques Réda's Ferveur de Borges (1987), a collection of essays and poems published individually between 1957 and 1986, where the author expresses his admiration for Borges, shows his broad and critical knowledge of Borges's works and establishes the similarities between their poetics of the urban and poetics of the self. Another important aim of this thesis is therefore to ascertain the extent of Borges's influential role in Réda's poetics, but also how reading Borges through Réda enhances our understanding of Borges's urban poetry. This comparison reveals that Borges and Réda gravitate towards places within the city, but mostly its periphery, characterised by their unpretentious, soulful and heterotopic qualities — places where the poets feel a sense of belonging. Their objective is to restore, through the prism of their minds and their physical investment in space, the provincial spirit of Buenos Aires and Paris, hidden behind the dynamism of the modern metropolises they have become. As a consequence of this communion between self and place they explore the possibility of being on the brink of a revelatory experience that speaks to the enigma of life. The wider scope of the thesis addresses the historical and cultural relationship between Buenos Aires and Paris, Borges's and Réda's redefinition of the centre/periphery dichotomy, the evening as a temporal locale and the distinction between poetic destiny and aesthetic experience.

Advisor: Sheringham, M
Williamson, E
A theological response to the "illegal alien" in federal United States law

Today, some twelve million immigrants are unlawfully present in the United States. What response to this situation does Christian theology suggest for these immigrants and those who receive them? To this question about the status of immigrants before the law, the theological literature lacks an understanding of how federal U.S. immigration law developed, and it lacks a robust theological account of the governance of immigration. To fill this gap, the thesis presents three stages in the formation of the laws that designate some immigrants as aliens unlawfully present or illegal aliens, drawing out the moral argumentation in each phase and responding with moral theology. In the first stage, non-citizens were called aliens in U.S. law. In response to the argument that aliens exist as a consequence of natural law, Christian teaching indicates that immigrants are not alien either in creation or for the church. In the second stage, the authority of the federal government to exclude and expel aliens was established, leaving those who do not comply to be designated illegal aliens. To the claim that the federal government has unlimited sovereignty over immigration, interpretations of the Christian Scriptures respond that divine sovereignty limits and directs civil authority over immigration. In the third stage, legal reforms that were intended to end discrimination between countries allowed millions from countries neighboring the U.S. to become illegal aliens. These reforms turn out to be unjust on philosophical grounds and unneighborly on theological grounds. While federal law classes many as aliens unlawfully present in the United States, Christian political theology indicates that immigrants are not alien, the government of immigration is limited by divine judgment, and nationals of neighboring countries deserve special regard.

Keywords: aliens
Book of Psalms
Christian ethics
territory
illegal immigration
Gospel of Luke
Edward Coke
corrective justice
Hugo Grotius
Emer de Vattel
Martin Luther
attributive justice
international relations
1880's Chinese immigration
deuteronomy
Aristotle
Book of Genesis
Mexico-US migration
moral theology
common law
migrants
Thomas Hobbes
nationhood
legal history
1 Corinthians
political theology
political theory
Karl Barth
sovereignty
William Blackstone
distributive justice
Advisor: Biggar, N
A study of the response of English poets to the South African War of 1899-1902

This thesis examines the controversial South African War's influence on English poetry, highlighting the individual responses of established poets and drawing on the work of numerous minor verse-writers to define the changing tradition of 'patriotic' and 'war' poetry.
Chapter I sketches the historical and social background, noting how events in South Africa assumed great magnitude for contemporaries whose popular Imperialism was severely tried and who made an unprecedented national 'war-effort'.
In Chapter II the late-nineteenth-century tradition of 'patriotic' poetry is identified, through analysis of verse-anthologies and contemporary critical opinion, and by briefly studying the war's lesser poetry which confirmed this mood of Art-for-Morality's-sake writing.
Chapter III describes Kipling's personal affection for South Africa, and the political aspirations which were related to his dedicated 1890s' verse-lessons. His reactions to the conflict reveal the disillusionment which distanced Kipling from his audience and changed his patriotic and imperialistic teaching.
Inflated by the war, 'Rudyard Kiplingism' became a powerful literary movement. Chapter IV explains the discredit brought by Robert Buchanan's 'Hooligan' criticism, Edgar Wallace's 'barrack-room ballad' imitations, and Kipling's own ill-judged verses 'The Absent-Minded Beggar', but also argues that certain soldier-poets usefully exploited his reputation.
Chapter V evaluates the contributions of four respected and influential patriotic poets: the 'undistinguished adequacy' of Alfred Austin, Poet Laureate; the strident verses of W.E. Henley; Henry Newbolt's strongly idealistic encouragement and consolation; and William Watson's brave but costly anti-war stance.
Chapter VI considers a variety of poets in demonstrating how, while religious sanction for human conflict and empire-building was emphatically re-affirmed, some questioned the principle of War (including Meredith and Hardy) and denounced the sufferings inflicted on the Boers.
The strain imposed on fireside poets' customary responses and rhetoric is outlined in Chapter VII, which also discusses the sentiments of Hardy's discontented 'war-poetry' and The Dynasts, before assessing the impact of personal bereavement on A.E. Housman's loyal poetry.
On some aspects of the concept of truth

Two aspects of truth constitute the subject of investigation in this thesis. These two aspects arise in the dependence of truth on language and fact. A statement is true or false, as the case may be, jointly in virtue of what it means and of how things are. This double dependence . of truth on meaning and reality establishes prima facie interconnections between these notions, which I am here concerned to analyse.
Consideration of these interconnections with respect to individual sentences suggests that truth is dependent on meaning. After all, we cannot begin to assess a statement as to its veracity unless we first understand it, that is to say, grasp its meaning. This claim is unexceptionable, but only from a vantage point which precludes a general understanding of the concepts involved. It quite leaves out of account the evident consideration that it is only in the context of a language that a collocation of symbols or sounds is endowed with sense- While it must be that, to determine the truth or falsity of a statement, we have first to know its meaning, it does not follow that the concept of truth is to be analysed in terms of meaning. And indeed, at the level where we consider meaning in terms of the systematic functioning of language, we find that truth underlies meaning. In §1.2,1 consider four arguments which aim to show that an answer to the question "how is a statement endowed with meaning?'' is to be couched in terms of truth.
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Mechanism of SigR inhibition by the anti-sigma factor RsrA from Streptomyces coelicolor

The extracytoplasmic function (ECF) sigma factor SigR (σR) is a bacterial transcription factor involved in the regulation of cytosolic redox homeostasis in Streptomyces coelicolor. SigR activity is regulated by its cognate anti-sigma factor RsrA. RsrA is a member of the zinc-anti-sigma (ZAS) family, which in its reduced state binds a single Zn2+ ion coordinated by 3 cysteine residues and a histidine. RsrA senses oxidative stress within the cytosol and responds by the formation of intramolecular disulphide bonds between its Zn-ligating cysteine residues. This results in the loss of the metal ion, a conformational rearrangement, and dissociation of SigR by an unknown mechanism. This releases SigR to bind RNA polymerase and direct the expression of a large regulon including that of the thioredoxin pathway, thereby re-establishing redox homeostasis. No structural information is available for the SigR-RsrA complex in Streptomyces coelicolor. Moreover, little is known of the mechanism by which RsrA associates with SigR and regulates gene transcription, or the role of zinc in SigR binding. In this work, a stopped-flow fluorescence-based assay was developed for investigating the kinetics of SigR-RsrA complex formation to aid our understanding of the role of the metal ion. Ultimately, trying to understand how oxidative stress causes dissociation of the Streptomyces coelicolor complex. Through tryptophan fluorescence emission quenching experiments, the SigR region 2 tryptophan (W88) and region 4 tryptophan (W159) were found to be sensitive to RsrA binding, likely denoting the binding sites for the anti-sigma factor. Pre-steady state experiments demonstrated that the metal ion has little effect on the rate of association (Kon 8.9 and 17.3x106 M-1s-1 at 35°C in the presence and absence of zinc, respectively) but a large effect on the dissociation rate constant (>500-fold faster in the absence of zinc at 35°C). Moreover, the kinetically derived Kds (0.27 nM and 62.4 nM with and without zinc respectively) agreed with the equilibrium constant for the complex derived through isothermal titration calorimetry (0.78 nM and 101.7 nM), validating the kinetic model for binding experiments. Zinc therefore has an important role in the structure of RsrA, affecting SigR-RsrA complex affinity, the off-rate for the complex and inhibition of SigR activity. Future work will exploit these assays to determine the role of zinc in redox sensing by RsrA.

Keywords: Biochemistry
Biophysics
microbiology
protein interactions
Advisor: Kleanthous, C