VictorJuiz/thesis huggingface dataset:
Indentation creep and anisotropy in magnesium oxide and germanium

Hardness tests have the potential to provide a simple means of investigating the mechanical properties of materials, both at room temperature, and at higher temperatures. However, the information gained can not be fully utilized unless the deformation processes and variables are properly understood. Careful consideration of such deformation on single crystals can help to clarify the situation and lead to better understanding.
This thesis describes indentation experiments on (001) MgO and Ge at temperatures up to 1175°C and 700°C respectively. Since anisotropy was one of the questions being addressed, the majority of the testing used Knoop indenters, although a few experiments used Vickers indenters. The work was carried out on a specially commissioned high temperature hardness tester (based on an original design by Wilberforce Scientific Developments). A main conclusion of the discussion on the design of high temperature hardness testers is the importance of independent heating of the indenter for accurate hardness results.
The indentation behaviour of MgO was shown to include creep, even at room temperature for the Knoop <110> orientation. However a region of no indentation creep was exhibited between 750°C and 1050°C for both Vickers and Knoop indentations. This has not been reported in previous studies. The anisotropy displayed at room temperature between <110> and <100> Knoop decreased with increasing temperature, due to the faster creep rate of the < 110> orientation, and finally reversed.
Knoop indentations in the <110> and <100> orientations on Ge also showed hardness anisotropy which changed with temperature. In this case there was no anisotropy at room temperature, but anisotropy developed as the temperature increased due to the faster creep rate of the <110> orientation.
The indentation hardness response of both MgO and Ge is explained in terms of the interaction of dislocation arrays which are formed in the first few moments of the indentation. Measurement of the two diagonals of the Knoop indentations showed that the ratio of the diagonal lengths, and also the morphology of the surrounding material, can be used to examine the extent and direction of material displacement. Surface etching, and etching of sections, were used to analyse the disposition of slip around the indentations.

Advisor: Roberts, S
Expression and neural correlates of schizophrenia risk gene ZNF804A

Genome wide association studies have provided evidence for a significant association between ZNF804A (zinc finger protein 804A) - specifically the intronic single nucleotide polymorphism (SNP) rs1344706 - and schizophrenia, but little is known about the function of the gene or the effects of the SNP. By studying post-mortem human brain tissue, I characterised ZNF804A immunoreactivity in adult and foetal human brain and investigated effects of diagnosis and rs1344706 genotype on ZNF804A mRNA and protein expression. Secondly, I looked in a large sample of healthy volunteers (n=922) at the effects of rs1344706 on brain structure using volumetry and voxel based morphometry (VBM). Furthermore, I recruited healthy volunteers who were either homozygous for the risk allele or homozygous for the non-risk allele (n=50). They participated in magnetoencephalography (MEG) and magnetic resonance (MR) sessions in which brain activity was measured during a working memory task, a visual processing task, and rest. Using magnetic resonance spectroscopy, also neurotransmitter levels were assessed. The experiments conducted for this thesis showed for the first time that ZNF804A immunoreactivity can be detected in both foetal and adult human brain and that it is mainly localised to layer III pyramidal cells, with a granular subcellular distribution throughout the cytoplasm. No effect of rs1344706 on mRNA and protein expression was found. In our structural MRI study, rs1344706 did not affect macroscopic brain structure as measured by volumetry and VBM, and given the large sample size, this seems a convincing negative. However, we did find that rs1344706 alters prefrontal-hippocampal connectivity, with increased connectivity being observed in risk homozygotes. Additionally, using MEG, we found an effect of ZNF804A genotype on hippocampal connectivity in the theta band (4-8Hz), with non-risk homozygotes displaying more connectivity. This finding provides a first clue as to the mechanisms that might underlie the previously observed effects of rs1344706 on prefrontal-hippocampal connectivity. Future studies will need to elucidate the actual function of the ZNF804A protein, in order to bridge the gap between the molecular and neuroimaging findings described in this thesis.

Keywords: risk gene
ZNF804A
human brain tissue
schizophrenia
neuroimaging
Advisor: Harrison, P
Nobre, A
Abstract interpretation of domain-specific embedded languages

A domain-specific embedded language (DSEL) is a domain-specific programming language with no concrete syntax of its own. Defined as a set of combinators encapsulated in a module, it borrows the syntax and tools (such as type-checkers and compilers) of its host language; hence it is economical to design, introduce, and maintain. Unfortunately, this economy is counterbalanced by a lack of room for growth. DSELs cannot match sophisticated domain-specific languages that offer tools for domainspecific error-checking and optimisation. These tools are usually based on syntactic analyses, so they do not work on DSELs.
Abstract interpretation is a technique ideally suited to the analysis of DSELs, due to its semantic, rather than syntactic, approach. It is based upon the observation that analysing a program is equivalent to evaluating it over an abstract semantic domain. The mathematical properties of the abstract domain are such that evaluation reduces to solving a mutually recursive set of equations. This dissertation shows how abstract interpretation can be applied to a DSEL by replacing it with an abstract implementation of the same interface; evaluating a program with the abstract implementation yields an analysis result, rather than an executable.
The abstract interpretation of DSELs provides a foundation upon which to build sophisticated error-checking and optimisation tools. This is illustrated with three examples: an alphabet analyser for CSP, an ambiguity test for parser combinators, and a definedness test for attribute grammars. Of these, the ambiguity test for parser combinators is probably the most important example, due to the prominence of parser combinators and their rather conspicuous lack of support for the well-known LL(k) test.
In this dissertation, DSELs and their signatures are encoded using the polymorphic lambda calculus. This allows the correctness of the abstract interpretation of DSELs to be proved using the parametricity theorem: safety is derived for free from the polymorphic type of a program. Crucially, parametricity also solves a problem commonly encountered by other analysis methods: it ensures the correctness of the approach in the presence of higher-order functions.

Keywords: program analysis
parametricity
attribute grammars
theorems for free
parser combinators
abstract interpretation
domain specific languages
functional programming
Advisor: Sufrin, B
Structural analysis of silk proteins using x–ray and neutron scattering

The silk fibres spun by insects and spiders have intrigued scientists for many years. Their mechanical performance is remarkable when one considers that the fibres are spun under ambient conditions from aqueous protein solutions without requiring many of the harsh processing conditions used in the production of man-made fibres. Yet, despite this interest, very little is known about the initial structure of the precursor proteins prior to spinning. One reason for this lies in the difficulty of handling the native proteins without accidental aggregation. Therefore in this thesis a novel sample preparation protocol for native silk is developed and small angle scattering (SAS) techniques are combined with circular dichroism (CD) and atomic force microscopy (AFM) to examine the structure and morphology of the proteins with different mechanical properties and thus biological function in nature. This work highlights the importance of studying native, functional proteins, at close to in vivo conditions, since clear differences in the structure and interaction of native and reconstituted silks can be attributed to the additional processing which reconstituted silks have undergone in order to be solubilised. Indeed native silk proteins are found to be more inherently non-interacting at quite high protein concentrations than reconstituted silk. Upon dilution, inter-chain interactions can be observed by SAS and CD as the protein is driven from its equilibrium conformation. This interaction and the shear-induced assembly of these proteins are also followed by AFM. Interestingly, native silk proteins from spider and silkworms retain a semiflexible conformation in solution. Indeed by comparing the silks from the major and minor ampullate, flagelliform and cylindriform glands of Nephila edulis with the cocoon silk of Bombyx mori silkworms, important insights are gained into how their flexibility suggests similarities in the local environment of the protein chains thereby dictating the hierarchical structure of silk fibres.

Keywords: proteins
structural analysis
AFM
scattering
silk
Advisor: Vollrath, F
Early twentieth-century discourses of violin playing

The thesis is a critical reading of pedagogical and biographical texts by and on violinists, written in the early twentieth century. It contributes to historical and discursive studies by providing a limited engagement with a largely neglected group of historical sources relating to musical performance, and further advances the historical research on subjectivity, the body, pathology, and erotics, in relation to discourses of music. The thesis also contributes to studies of performance practice, and empirical and psychological studies of musical performance, in that it engages with discursive notions of theoretical and performance categories, such as tempo, melody, vibrato and portamento. By taking a hermeneutic approach to detailed discussions of performative practices, primarily found in pedagogical texts, the project aims to provide a more nuanced assessment of many of the topics that have played a central role in the ongoing research on early twentieth-century performance (which principally consists of recordings analysis). The project does this by demonstrating the extent to which these practices are culturally and historically mediated.
Following an introduction, chapter 2 demonstrates that notions of consciousness inform writers’ notions of musical virtuosity, and shows that Nietzschean and Wagnerian notions of self underpin the idea of the violinist as a superior producer of art. Chapter 3 argues that these ideas combine with metaphysical notions of melody to make the concept of ‘tone’/Ton the cornerstone of string playing during this period, which in turn has important implications for how writers conceive of tempo, rhythm, vibrato, portamento and dynamics. Chapter 4 demonstrates that writers perceive their ideal of tone to be threatened by moral and physiological disease, manifested in individual/social bodies, which leads to a very different articulation of these same practices. Chapter 5 explores traces of notions of intersubjectivity, arising from metaphors of erotic desire, which challenge the hegemonic ideal of universal mind. The conclusion frames the discourse as a problematic attempt to posit an authoritarian model of string playing. It also includes a preliminary study of early twentieth-century discourses of cello playing, and engages with the research to date on national styles of violin playing in the same period.

Keywords: tone
early twentieth century performance
voice
vitalism
cello
Auer
subjectivity
string playing
violin
performance discourse
performance practice
Joachim
late-nineteenth century performance
pathology
Flesch
Advisor: Clarke, E
Secondary frost heave in freezing soils

Frost heave describes the phenomenon whereby soil freezing causes upwards surface motion due to the action of capillary suction imbibing water from the unfrozen region below. The expansion of water on freezing is a small part of the overall surface heave and it is the flow of water towards the freezing front which is largely responsible for the uplift. In this thesis, we analyse a model of frost heave due to Miller (1972, 1978) which is referred to as secondaryostheave′.secondaryostheaveischaracterisedbytheeξstenceofa
partially frozen zone', underlying the frozen soil, in which ice and water coexist in the pore space. In the first part of the thesis we follow earlier work of Fowler, Krantz and Noon where we show that the Miller model for incompressible soils can be dramatically simplified. The second part of the thesis then uses this simplification procedure to develop simplified models for saline and compressible soils. In the latter case, the development of the theory leads to the consideration of non-equilibrium soil consolidation theory and the formation of segregated massive ice within permafrost. The final part of the thesis extends the simplified Miller model to the analysis of differential frost heave and the formation of patterned ground (e.g. earth hummocks and stone circles). We show that an instability mechanism exists which provides a plausible theory for the formation of these types of patterned ground.
A different mimesis: the fantastic in Italy from the Scapigliati to the postmodern

This thesis investigates the literary fantastic in Italy from the late nineteenth century to the second half of the twentieth century. The purpose is to analyse the way in which the fantastic functions in a story—its ʻmechanicsʼ—and to see how the fantastic evolved structurally over the first century of its existence in Italy. This investigation is carried out by the development of a new theoretical methodology together with the close reading of a selection of texts from four key Italian authors of fantastic literature.
The thesis is divided into six chapters. The first chapter is a historical overview of the emergence of the fantastic in Italy in the late nineteenth century up to the second half of the twentieth century; it examines the obstacles the fantastic has faced and some of the thematic and structural characteristics of texts which emerge. The second chapter is a literature review of the theoretical models used to analyse and understand the fantastic, followed by an outline of a new model, entitled Different Mimetics, which looks at the internal logic of the fantastic.
In the following four chapters Different Mimetics is applied to the study of a selection of fantastic texts by four authors. Chapter three focuses on Ugo Tarchetti, and shows that his stories are defined by coexistence and coincidence in both historical and thematic terms. Chapter four demonstrates how Giovanni Papini reverses the mechanics one might expect, and how his stories are structured as internal narratives. Chapter five looks at how Dino Buzzatiʼs stories are characterised by instability and stretched narrative paradigms; and finally, chapter six looks at how Italo Calvinoʼs narratives focus on world creation and paradox and how they question the stability of narrative paradigms.

Keywords: fantastic literature
nineteenth century
literary history
Ugo Tarchetti
Dino Buzzati
Giovanni Papini
fantasy literature
Italo Calvino
literary theory
Italy
twentieth century
Advisor: Bonsaver, G
The impact of climate change on the small island developing states of the Caribbean

Small Island Developing States (SIDS) of the Caribbean are one of the world’s ‘hottest’ ‘biodiversity hotspots’. However, this biodiversity continues to be threatened by habitat loss, and now, by climate change.
The research reported here investigated the potential of species distribution modelling (SDM) as a plant conservation tool within Caribbean SIDS, using Trinidad as a case study. Prior to the application of SDM, ancillary analyses including: (i) quantification and mapping of forest cover change (1969 to 2007) and deforestation rates, and (ii) assessment of the island’s vegetation community distribution and associated drivers were carried out.
Community distribution and commercial importance and global/regional rarity were used to generate a list of species for assessing the potential of SDM within Trinidad. Species occurrence data were used to generate species distribution models for present climate conditions within the SDM algorithm, MaxEnt. These results were assessed through expert appraisal and concurrence with results of ecological analyses. These models were used to forecast suitable species climate space forty years into an SRES A2 future. Present and future models were then combined to produce a ‘collective change map’ which showed projected areas of species’ range expansion, contraction or stability for this group of species with respect to Trinidad’s Protected Areas (PAs) network.
Despite the models being indicative rather than accurate, it was concluded that species’ climate space is likely to decrease or disappear across Trinidad. Extended beyond Trinidad into the remainder of the Caribbean region, SDM may be a crucial tool in identifying which PAs within the region (and not individual islands) will facilitate future survival of given target species. Consideration of species conservation from a regional, rather than an individual island perspective, is strongly recommended for aiding the Caribbean SIDS to adapt in response to climate change.

Keywords: Small Island Developing States (SIDS)
Species Distribution Modelling
climate change
MaxEnt
biodiversity
Caribbean
forest cover
Protected Areas Network
Advisor: Brown, N
Harris, S
New, M
Fat metabolism and the metabolic syndrome

Background: The metabolic syndrome is associated with an increased risk of diabetes and vascular disease. In order to understand the pathophysiological processes underlying such risk, it is necessary to develop a better understanding of normal fat metabolism and abnormalities associated with the syndrome. The hypothesis tested in this thesis is that specific abnormalities in adipose tissue and muscle fat metabolism characterise the metabolic syndrome. Methods: Fasting biochemical parameters were measured in a cohort of overweight men with and without the metabolic syndrome. Stable-isotope labeling and arterio-venous difference measurements were conducted in 18 men to elucidate pathways of exogenous and endogenous fat metabolism under fasting and postprandial conditions in adipose tissue and skeletal muscle. In addition, a pilot study of the effects of heat and electrical stimulation on adipose tissue metabolism was undertaken. Results: Cohort study - The prevalence of the metabolic syndrome depended on the definition used. Total cholesterol and apoB were greater in those with the metabolic syndrome than in those without. There was no difference in fasting NEFAs. Metabolic investigation - There was significant postprandial uptake of NEFA from the circulating NEFA pool by adipose tissue. Chylomicrons were confirmed as the preferred substrate of LPL. There was preferential uptake of FAs derived from chylomicron hydrolysis. There was release of NEFA across muscle. In the metabolic syndrome, adipose tissue NEFA output is lower during fasting and falls less following a meal than in the healthy obese. Clearance of dietary-derived TG is lower across both adipose tissue and muscle in the metabolic syndrome. Pilot study – Heat increased measures of lipolysis whereas electrical stimulation had no effect. Conclusions: Fat metabolism in individuals with the metabolic syndrome is characterised by metabolic inflexibility but not insulin resistance.

Keywords: fat metabolism
metabolic syndrome
Advisor: Frayn, K
Karpe, F
Soviet doctrine justifying military intervention from 1945 to 1989

This thesis is about the Soviet doctrine used to justify or threaten military intervention since 1945. This interventionist doctrine achieved greater currency in 1968 in the form of the "Brezhnev Doctrine". This doctrine, generally associated with the 1968 Soviet invasion of Czechoslovakia, stipulated that Moscow reserved the right to intervene militarily or otherwise if developments in any given socialist country inflicted damage on socialism within that country or the basic interests of other socialist states. The ideological justification for the Soviet invasion was assumed by many observers to have been a quickly engineered reaction to the crisis, rather than a long-standing doctrine. This thesis suggests, however, that the "Brezhnev Doctrine" was not an original formula, but a newer version of a previous doctrine.
The thesis traces the origins of the "Brezhnev Doctrine". It examines four crises in Soviet-East European relations for evidence of the doctrine. The thesis looks at how the effectiveness of the doctrine as a tool of Soviet foreign policy began to decline in the mid-1970s. While the doctrine appeared to be extended to the Third World - Afghanistan 1979 - and was "self-administered" by an East European country - Poland 1981 - it proved far less successful than in the past in suppressing opposition. Finally, the thesis examines the demise of the doctrine under Mikhail Gorbachev.
The conclusions drawn by this thesis are: that the Soviet interventionist doctrine was not a new phenomenon; that it contained political, ideological, and military components; and, that it served a number of functions within the socialist community.
Duality theory for optimal mechanism design

In this work we present a general duality-theory framework for revenue maximization in additive Bayesian auctions involving multiple items and many bidders whose values for the goods follow arbitrary continuous joint distributions over some multi-dimensional real interval. Although the single-item case has been resolved in a very elegant way by the seminal work of Myerson [1981], optimal solutions involving more items still remain elusive. The framework extends linear programming duality and complementarity to constraints with partial derivatives. The dual system reveals the natural geometric nature of the problem and highlights its connection with the theory of bipartite graph matchings.
We demonstrate the power of the framework by applying it to various special monopoly settings where a seller of multiple heterogeneous goods faces a buyer with independent item values drawn from various distributions of interest, to design both exact and approximately optimal selling mechanisms. Previous optimal solutions were only known for up to two and three goods, and a very limited range of distributional priors. The duality framework is used not only for proving optimality, but perhaps more importantly, for deriving the optimal mechanisms themselves.
Some of our main results include: the proposal of a simple deterministic mechanism, which we call Straight-Jacket Auction (SJA) and is defined in a greedy, recursive way through natural geometric constraints, for many uniformly distributed goods, where exact optimality is proven for up to six items and general optimality is conjectured; a scheme of sufficient conditions for exact optimality for two-good settings and general independent distributions; a technique for upper-bounding the optimal revenue for arbitrarily many goods, with an application to uniform and exponential priors; and the proof that offering deterministically all items in a single full bundle is the optimal way of selling multiple exponentially i.i.d. items.

Keywords: approximation algorithms
duality
optimal auctions
revenue maximization
game theory
mechanism design
Advisor: Koutsoupias, E