VictorJuiz/thesis huggingface dataset:
Essays in corporate finance

This thesis contributes to the empirical literature on how firms meet exceptional financing needs in relation to “investment spikes” or years with unusually large investment activities. In the earlier part of the thesis, I show that the financing of investment during an investment spike is very different from that at other times. I have done this using data for publicly traded US firms over the period 1988 to 2007 and a filtering procedure suggested by Bond et al. (2006). Specifically, external finance, in particular debt finance, is very important in financing investment in years categorized as investment spikes, confirming the findings of Mayer and Sussman (2005). In addition, it has been found that firms with smaller size, lower profitability, more future growth opportunities, fewer tangible assets and more R&D; spending tend to use more equity finance in relation to large investment requirements. I also propose the use of the Markov-switching filter to identify investment spikes. In implementing the Markov-switching filter, I apply a first-order two-state Markov-switching mean model to the investment rates de-trended using Hodrick and Prescott's (1997) filter. A Gibbs-sampling procedure is used to produce the marginal posterior distributions of unobserved state variables and model parameters. Among other advantages, this filter allows us to identify multi-year investment spikes. I show that two-year investment spikes identified by the Markov-switching filter are financed quite similarly to single-year investment spikes and that main findings are robust to calendar-time-dependent clustering of investment spikes generated by macroeconomic shocks. In the later part of the thesis, I find there is a positive effect of share liquidity on the propensity to raise debt finance. Using a sample of firm-year observations identified as investment spikes, I find that firms with more liquid shares tend to rely more heavily on debt to finance investment spikes. This result is robust to a control for the effects of firm size and other firm characteristics, the use of various leverage measures, and the use of a whole sample with investment spike characteristics. Another important finding is that firms with more liquid shares tend to have higher target leverage ratios. One interpretation of these results is that information spillovers from the presence of more informative share prices allow firms with more liquid shares to borrow on more favourable terms in normal times, as well as to obtain additional debt finance at lower costs when taking advantage of unusually large investment opportunities.

Keywords: Markov-switching filter
financing patterns
leverage
investment spikes
liquidity
Advisor: Sussman, O
Bond, S
The ZEUS first level tracking trigger and studies of supersymmetry at HERA

The HERA accelerator, an electron-proton collider facility based at the DESY laboratory in Hamburg, started delivering luminosity to the ZEUS experiment in May 1992. The short time of 96ns between bunch crossings and the fact that the primary source of detector activity in ZEUS does not come from the e-p interactions of interest but rather from other sources makes a high performance three level trigger system essential to data-taking. We present one part of the ZEUS trigger system, the Central Tracking Detector First Level Trigger (CTD-FLT). The principle of operation and the hardware implementation are discussed at length. A prototype system which was used during the early stages of ZEUS data-taking is described. We detail the principles of the CTD-FLT hardware testing and discuss aspects of the First Level Trigger data from the 1993 running period. During this time the CTD trigger has proved to be an invaluable part of the overall system.
The high energies accessible at HERA make it possible to probe a variety of new physics models. The second part of this thesis focuses on one such model - Supersymmetry (SUSY). After an introduction to the model, a search for R-parity violating SUSY in the ZEUS data from the 1992 running period is described. No evidence for such signals has been found and hence we set upper limits on the mass scale of the theory. Finally we present a Monte Carlo study of the potential discovery reach of HERA for R-parity violating SUSY models, and come to the conclusion that HERA is an ideal place to look for such phenomena.
Atomic scale studies of thermally aged pressure vessel steels

In Pressurised Water Reactors, the reactor pressure vessel (RPV) is considered a life limiting component due to the degradation of its mechanical properties. Nano-scale Cu-enriched precipitates are known to cause embrittlement in the form of increases in hardness and the ductile-to-brittle transition temperature. The effect of irradiation on the RPV is the dominant contributor to this embrittlement. This is due to the increased mobility of Cu from the high number of vacancies, and the matrix damage providing many heterogeneous nucleation sites. However, there are also thermal effects which may be difficult to separate from the irradiation effects.
To understand the contribution of the long term thermal ageing to RPV embrittlement a series of weld and plate materials containing systematic variations of Ni and Cu has been thermally aged for times up to 100,000 hrs at 330 degrees C, 365 degrees C and 405 degrees C. Microstructural characterisation using Atom Probe Tomography has been performed. Complimentary Monte-Carlo simulations have been used to investigate the early stages of formation of Cu-enriched precipitates.
Thermal ageing produces a high number density of nano-scale Cu-enriched precipitates. These nanometre precipitates have a Ni-Mn-Si rich interface which was found to be wider with increased precipitate size, lower ageing temperature and higher bulk Ni content. This interface reduces the interfacial energy of the Cu-enriched precipitates through a combination of the minimising of unfavourable Fe-Cu bonds and reduction in lattice strain. The matrix Cu levels after ageing for 90,000 - 100,000 hrs were found to be around 0.06 - 0.07 at.%, close to the expected solubility limits for Cu in Fe. The Fe content of the precipitates has been characterised and found to be higher at lower ageing temperature and for smaller precipitate sizes. Cu precipitation and solute segregation at dislocations were observed, particularly in the SG steels aged at higher temperatures where the supersaturation is lowest.
Movies were produced from the Kinetic Monte-Carlo modelling (see accompanying DVD) and along with other analyses indicated that sub-critical Ni and Mn clusters may be active in the formation of Cu-enriched precipitates. This mechanism appears to occur in both the high and low Ni steels. Thus, the higher number density of larger precipitates observed with increased bulk Ni content is thought to be a consequence of the greater number of sub-critical Ni-Mn clusters providing more nucleation sites.
A small number of grain boundaries were examined. Segregation of many solute species to them was observed, which is thought to result from a multi-element co-segregation process. Ni-Mn-Si precipitates were observed at grain boundaries and dislocations in the high Ni steels with high and low Cu levels. These are consistent with similar phases in found in irradiated high Ni steels. In the high Cu steels these particles were much larger and associated with Cu-enriched precipitates.

Keywords: RPV
steels
nuclear materials
thermal ageing
atom probe
Advisor: Smith, G
Hyde, J
The role of DNA methylation in the regulation of depot-specific gene expression in human adipose tissue

Adipose tissue is not homogenous as individual fat depots display regional variation in their physiological properties. It follows that body fat distribution is increasingly being recognised as a major determinant of metabolic disease risk. At the cellular level, depot-specific properties are exhibited by adipocyte precursors during in vitro culture and persist for many generations, suggesting these cells retain an ‘intrinsic memory’ of their anatomical origin which is epigenetic in nature. A primary aim was to identify depot-specific genes whose expression may be regulated by DNA methylation in adipose precursors.
Using two paired preadipocyte cell lines derived from human subcutaneous abdominal and gluteal adipose tissue - to represent upper and lower body fat with their opposing associations with cardiovascular disease and diabetes respectively - depot-specific gene expression and DNA methylation profiles were detected. Furthermore, the expression of certain genes in preadipocytes was found to change in response to treatment with the DNA demethylating agent 5-azacytidine, which suggests DNA methylation may regulate depot-specific gene expression. A secondary aim was to investigate whether glucocorticoids – which are important determinants of body fat distribution – exert their effects through DNA methylation. The synthetic glucocorticoid dexamethasone was found to modulate the expression of some of the differentially expressed genes in preadipocytes, with this effect possibly being mediated by DNA methylation. It has been postulated that depot-specific phenotypes in adipose tissue may arise from developmental differences. Several genes were found to be expressed in a depot-specific fashion during a differentiation time course, suggesting regional variation in adipogenesis may contribute to the generation of depot-specific phenotypes.
Overall, the data presented suggests regional variation within subcutaneous white adipose tissue exists and supports the notion that DNA methylation patterns can, in part, determine adipose tissue heterogeneity.

Keywords: glucocorticoids
DNA methylation
Adipose
5-azacytidine
epigenetics
Advisor: Karpe, F
Pinnick, K
The real field with an irrational power function and a dense multiplicative subgroup

In recent years the field of real numbers expanded by a multiplicative subgroup has been studied extensively. In this thesis, the known results will be extended to expansions of the real field. I will consider the structure R consisting of the field of real numbers and an irrational power function. Using Schanuel conditions, I will give a first-order axiomatization of expansions of R by a dense multiplicative subgroup which is a subset of the real algebraic numbers. It will be shown that every definable set in such a structure is a boolean combination of existentially definable sets and that these structures have o-minimal open core. A proof will be given that the Schanuel conditions used in proving these statements hold for co-countably many real numbers. The results mentioned above will also be established for expansions of R by dense multiplicative subgroups which are closed under all power functions definable in R. In this case the results hold under the assumption that the Conjecture on intersection with tori is true. Finally, the structure consisting of R and the discrete multiplicative subgroup 2^{Z} will be analyzed. It will be shown that this structure is not model complete. Further I develop a connection between the theory of Diophantine approximation and this structure.

Keywords: Diophantine Approximation
Power Function
Model Theory
O-minimality
Schanuel's Conjecture
Advisor: Wilkie, A
Analysis and synthesis of inductive families

Based on a natural unification of logic and computation, Martin-Löf’s intuitionistic type theory can be regarded simultaneously as a computationally meaningful higher-order logic system and an expressively typed functional programming language, in which proofs and programs are treated as the same entities. Two modes of programming can then be distinguished: in externalism, we construct a program separately from its correctness proof with respect to a given specification, whereas in internalism, we encode the specification in a sophisticated type such that any program inhabiting the type also encodes a correctness proof, and we can use type information as a guidance on program construction. Internalism is particularly effective in the presence of inductive families, whose design can have a strong influence on program structure. Techniques and mechanisms for facilitating internalist programming are still lacking, however.
This dissertation proposes that internalist programming can be facilitated by exploiting an interconnection between internalism and externalism, expressed as isomorphisms between inductive families into which data structure invariants are encoded and their simpler variants paired with predicates expressing those invariants. The interconnection has two directions: one analysing inductive families into simpler variants and predicates, and the other synthesising inductive families from simpler variants and specific predicates. They respectively give rise to two applications, one achieving a modular structure of internalist libraries, and the other bridging internalist programming with relational specifications and program derivation. The datatype-generic mechanisms supporting the applications are based on McBride’s ornaments. Theoretically, the key ornamental constructs — parallel composition of ornaments and relational algebraic ornamentation — are further characterised in terms of lightweight category theory. Most of the results are completely formalised in the Agda programming language.
Plasma evolution and continuum lowering in hot dense matter generated by X-ray free electron lasers 

The advent of the 4th generation X-ray sources paves the way for a new phase of experimental investigation of Hot-Dense plasmas. At the Linac Coherent Light Source (LCLS), pulses of keV X-rays, shorter than 100 fs, and with intensities up to 1018 W·cm-2, are routinely produced, allowing for the production of uniform samples of solid-density plasmas. The simple single-photon X-ray absorption mechanism can be easily modelled, so that the plasma conditions can be accurately retrieved, without relying on diagnostic techniques that are not benchmarked in this high density regime.
The work presented here describes the results of the first experiment where the LCLS interacts with a solid Al target, isochorically heating it at temperatures up to 190 eV. The system is described by the SCFLY non-LTE model, where the density and temperature are computed self consistently, as a consequence of the detailed atomic processes, rather than imposed by the user. The approximations affecting the simulations are discussed in detail.
The code is first validated, by modelling the charge state distribution measured in a previous experiment (L. Young et. al), where the LCLS interacts with a Ne gas, a simplified (collisionless) problem. Then it is used to model the K-alpha spectroscopic data obtained for Al. The plasma evolution, explained by SCFLY simulations, is found to be primarily determined by collisions, whose visible effects on the experimental spectra are discussed.
By varying the wavelength of the laser and observing the change in the K-alpha fluorescence, the K-edges for different ions in the plasma were determined, leading to a charge resolved measurement of continuum lowering in the HDM system. The results disagree with the widely used Stewart-Pyatt model, with the disagreement increasing for higher charge states, but are consistent with the older Ecker-Kroell model. These results have profound implications for dense plasma modelling.

Keywords: Plasma Physics
Continuum Lowering
FEL science
Advisor: Wark, J
The methods of quantitative taxonomy with special reference to functional analysis

The purpose of this thesis is to investigate the use of quantitative methods in taxonomy. Comparisons are made between, several quantitative methods and the relative mertis of these and the kinds of taxononomic information they produce are examined. To provide data on which to base those comparisons, measurements were made on the skulls of 20 hominoids and on the skeletons of 64 rodents ... [see pdf file for full abstract].
Unfolded protein responses in models of Motor Neuron Disease

Motor neuron disorders are a heterogeneous group of diseases characterized by the selective degeneration of motor neurons leading to muscle wasting and atrophy. Amyotrophic Lateral Sclerosis (ALS) is the most common amongst these disorders and is characterized by the selective loss of both upper and lower motor neurons in the brain and spinal cord. 20% of familial cases of ALS are caused by mutations in the Cu, Zn-superoxide dismutase gene (SOD1), a ubiquitously expressed enzyme responsible for scavenging superoxide radicals. The exact mechanisms underlying mutant SOD1-mediated neurotoxicity are unknown. Misfolded mutant SOD1 accumulates in the cytosol and mitochondrial intermembrane space (IMS) indicating the involvement of unfolded protein responses in ALS pathogenesis.
Unfolded protein responses (UPRs) are complex signal transduction cascades which detect perturbations in protein folding and couple them to the expression of protein quality control machinery thereby allowing individual compartments to adapt to stress. In the cytosol, this study has shown that HspB8 was upregulated by SOD1 mutants, where it induced the clearance of aggregates by macroautophagy. This is a protective mechanism, as overexpression of HspB8 suppressed mutant-SOD1 mediated toxicity. In contrast, HspB8 mutants were impaired in macroautophagy and are toxic to NSC-34 cells.
The mechanisms for the IMS-UPR have not been previously identified. To address this issue, a model for the accumulation of misfolded mutant SOD1 within the IMS was created and candidate proteins involved in protein quality control within the IMS were explored at the transcriptional level and at the level of protein expression. Preliminary results revealed some possible candidates that may have a role in the adaptation to mitochondrial stress. Interestingly, increased mitophagy was also found in IMS-G93A expressing cells, advocating the central role of macroautophagy in eliminating protein aggregates and damaged mitochondria in SOD1-FALS.

Keywords: unfolded protein responses
motor neuron disease
ALS
SOD1
Advisor: Talbot, K
Agashe, V
Exempla im Kontext. Untersuchungen zur Sammelhandschrift Berlin, Staatsbibliothek, mgf 863 aus dem Strassburger Reuerinnenkloster

The manuscript Berlin, SBB-PK, mgf 863 was written in about 1430 to 1435 and contains more than 600 short narrative texts in German prose (with some Latin insertions). Among them is the collection of the ›Alemannische Vitaspatrum‹ as well as an additional, extensive and multifarious exempla corpus, which mostly contains translations from well-known Latin collections such as – for example and most prominently – Caesarius' of Heisterbach ›Dialogus miraculorum‹. Because of the specific composition of the corpus and its large extent, mgf 863 builds an excellent basis for the investigation of exempla, a text type which has not received much attention in German studies.
The manuscript was probably produced in Strasbourg where it belonged to the library of the nuns from the convent of St Mary Magdalen. It contains a large quantity of textual material with close links to Strasbourg in terms of content or history of transmission. My primary interest is in the texts in the manuscript, in their contents and interdependencies, as well as in their history and their contextualization in, for example, groups of manuscripts, exempla tradition and religious practice. The project aims at a contribution to exempla research as well as to literary and religious life in Strasbourg in the late Middle Ages.
My approach comes primarily from literary studies, but also uses palaeographical, textualcritical, and historical methods. The thesis combines case studies of the transmission of individual exempla or groups of exempla with general research into the history of texts (›Textgeschichte‹) and the history of transmission (›Überlieferungsgeschichte‹) of German prose exempla. A repertory in the appendix provides an overview of the manuscript's content. It helps to orientate within the study; furthermore, with over 600 entries, it provides a tool for the identification of German exempla.

Keywords: German
manuscripts
Strasbourg
exempla
nunneries
Middle Ages
prose
literary topography
15th century
Advisor: Palmer, N
The painting career of Piero di Cosimo (1462-1522)

In The Painting Career ofPiero di Cosimo (1462-1522), I have sought to assemble a critical, monographic study of Piero's painting oeuvre that presently includes close to fifty works that are either extant or exist only in references and sources. The Florentine painter has historically proven to be among the most elusive artists of the Italian Renaissance and yet acted as a seminal figure in the artistic transitions occurring from the close of the fifteenth century to the beginnings of Mannerism in Florence.
My thesis consists of close iconographic and stylistic analyses that have been balanced by archival work and technical examination. The latter involved numerous meetings with restorers in United States and European conservation laboratories. The resulting in-depth study of the physical states of Piero's paintings as objects involving painting technique, working methods and present condition produces some of the most revealing results. My research with original documents and other primary sources in Florence also introduces a number of new discoveries, particularly from the early and middle stages of the painter's life and career.
The varied nature of Piero's art calls for a multidisciplinary approach. Combining iconographic, conservational and archival methods, I aim to contribute new insights into several specific areas. These include: a biographical grounding of Piero's life and those of his known patrons; Piero's advances in portraiture; the use of visual narrative forms and literary sources in Piero's mythologies; and the painter's large-scale devotional works.
The questioning of past assumptions concerning Piero's work and biography also leads me to consider the larger scope of influence, legacy and modes of transmission between Piero and other contemporary artists. As one of the most important older innovators, living well into the sixteenth century, Piero was a major catalyst for the new generation of highly inventive artists such as Andrea del Sarto and Pontormo, both of whom passed through his studio. It was Piero, however, who proved to be perhaps the most groundbreaking practitioner in the domestic secular painting tradition before his pupils' ascendance.

Advisor: Martin Kemp, D