VictorJuiz/thesis huggingface dataset:
D-orbifolds and d-bordism

The purpose of this thesis is to study d-manifolds and d-orbifolds and their bordism groups. D-manifolds and d-orbifolds were recently introduced by Joyce as a new class of geometric objects to study moduli problems in algebraic and symplectic geometry. In the spirit of Joyce we will introduce the notion of (stable) nearly and homotopy complex structures on these 2-categories and study their unitary bordism groups. Fukaya and Ono proved that the moduli space of n-pointed, genus g, J-holomorphic curves Mg,n(M,J,β) carries a so called stably almost complex structure, and as Kuranishi spaces are closely related to d-orbifolds, the introduction of complex structures will be essential in studying symplectic Gromov-Witten invariants using d-orbifolds.
We furthermore introduce the notion of representable d-orbifolds and prove that these representable d-orbifolds can be embedded into an orbifold. We will then explain how a result of Kresch can be used to show that many important moduli spaces in algebraic geometry, are representable and thus embeddable d-orbifolds. Moreover we will sketch how one could prove an analogous result in the symplectic case.
We then prove as one of our main results, that for a compact manifold the unitary d-bordism group is isomorphic to its ‘classical’ unitary bordism group. This result extends a result by Joyce who proved a similar statement for oriented manifolds and d-manifolds.
Furthermore we will introduce the notion of blowups in the 2-category of d-manifolds and prove that these d-blowups satisfy a universal property. Finally, we sketch how our results may be used to make a step towards a proof of the Gopakumar–Vafa integrality conjecture and a “resolution of singularities” theorem for d-orbifolds.

Advisor: Joyce, D
The assembly history of disc galaxies

We present new measures of the rotation curves of disc galaxies from z~0.2 to z~1.7, using deep exposures from both DEIMOS and LRIS spectrographs on the Keck telescopes in combination with multi-band imaging from the Hubble Space Telescope. We do this with a new modelling code, curvation, which has been optimised to extract the rotation velocity measurements from galaxies at intermediate and high redshift. To this end, we conduct a bulge-to-disc de-composition to allow us to de-project observed velocities to extract a model of the intrinsic rotation curve. We demonstrate the improved accuracy and precision of these measurements via a number of tests, but primarily in recovering an intrinsic scatter of the high redshift Tully-Fisher relation which is similar to that found locally. We show for the first time that the stellar mass Tully-Fisher relation is tightly in place at z~1, the normalisation of which has evolved less than 0.02±0.02 dex in stellar mass from z~1.7 to z~0.2. We do however see evidence for evolution in classic B-band Tully-Fisher relation, which is brighter at z~1 by 0.85±0.28 magnitudes than that at z~0.3. This trend is consistent with what was previously known about the evolving star-formation rates of disc galaxies. We then explore the potential drivers of these trends in the Tully-Fisher relation by estimating the baryonic and dark matter content of our galaxies. We also discover a surprising trend in the bulgeless disc galaxies at high redshift, which may be evolving differently from other rotationally supported galaxies. In the context of work which has been conducted at z~2, we discuss our results of a stellar mass Tully-Fisher relation which is strikingly similar over two-thirds of the age of the Universe.

Keywords: galaxy evolution
disc galaxies
disk galaxies
Tully-Fisher
galaxies
spiral galaxies
dark matter
Advisor: Sullivan, M
Ellis, R
The pyroclastic deposits and eruption history of Ascension Island

In this study, palaeomagnetic methods have been combined with field and volcanological techniques to identify, classify and correlate the pyroclastic deposits found on Ascension Island, South Atlantic, allowing them to be placed into a temporal and geographic framework. Pyroclastic material is abundant on the island and, in general, wellpreserved, making Ascension an ideal site to study the nature and distribution of the pyroclastic products of this type of composite volcano or stratovolcano. A better understanding of the nature and distribution of the products of past pyroclastic eruptions on Ascension should enhance our ability to assess volcanic hazard around stratovolcanoes world-wide.
Field mapping and stratigraphic logging have revealed the presence of several major pyroclastic sequences on Ascension. These comprise extensive felsic (pumice) and mafic (scoria) lapilli deposits, two major and several minor exposures of welded material and numerous breccia deposits that exhibit great variation in juvenile/lithic content, matrix type and content and internal structure. Preliminary interpretations of the deposits were made in the field, based on features such as welding, grain shape and internal structures. However many of the deposits - particularly the breccia deposits - display ambiguous field characteristics that could be attributed to pyroclastic or epiclastic processes and their origins could not therefore be determined from field characteristics alone.
[See pdf for continuation of abstract].

Advisor: C., B
Bryden, J
Wave evolution on gentle slopes - statistical analysis and Green-Naghdi modelling

An understanding of extreme waves is important in the design and analysis of offshore structures, such as oil and gas platforms. With the increase of interest in the shipping of LNG, the design of import and export terminals in coastal water of slowly varying intermediate depth requires accurate analysis of steep wave shoaling. In this thesis, data from laboratory experiments involving random wave simulations on very gentle slopes have been analysed in terms of a model of large wave events, and the results interpreted by observation of the shape and magnitude of the large wave events. The auto-correlation function of the free surface elevation time histories, called NewWave, has been calculated from the wave spectrum and shown to fit very well up to the point where waves start to break (when compared to the ‘linear’ surface elevation time history). It has been shown that NewWave is an appropriate model for the shape of the ‘linear’ part of large waves provided kd > 0.5. A Stokes-like expansion for NewWave analysis has been demonstrated to match the average shape of the largest waves, accounting for the dominant vertical asymmetry. Furthermore, an appropriate local wave period derived from NewWave has been inserted into a Miche-based limiting criterion, using the linear dispersion equation, to obtain estimates for the limiting wave height. Overall, the analysis confirms the Miche-type criterion applies to limiting wave height for waves passing over very mild bed slopes.
A derivation of general Green-Naghdi (GN) theory, which incorporates non-linear terms in its formulation, is also presented. This approach satisfies the boundary conditions exactly and approximates the field equations. The derived 2-dimensional vertical GN Level 1 model, capable of simulating steep waves on varying water depth, is validated against solitary waves and their interactions, and solitary waves on varying water depth and gives good qualitative agreement against the KdV equation. The developed and validated numerical model is used to simulate focussed wave groups on both constant depth and gentle slope. In general, the behaviour of waves simulated by the numerical model is very similar to that observed in the experimental data. There is evidence of vertical asymmetry as the water depth is reduced, owing to the non-linearity. Although the main physics is still controlled by linear dispersion, the higher order harmonics become increasingly important for shoaling waves. The numerical results also show a slope-induced wave set-up that keeps on increasing in amplitude as the wave group travels on the gentle slope.

Keywords: coastal and ocean engineering
computational fluid simulation.
Water waves
shoaling
Advisor: Taylor, P
Borthwick, A
Listening to Trypho

The primary focus of this thesis is the figure of Trypho in Justin Martyr's Dialogue with Trypho, A Jew (mid-second century C.E.). The substance of the thesis is an analysis of Trypho's depiction and function within the text. Focusing exclusively on Trypho provides a new lens through which to view the Dialogue. This approach has revealed instances where Justin's apologetic breaks down and gives an unintended glimpse behind the text. Lifting Trypho out of the text reveals a consistent figure who does not appear to be based on any Jewish stereotype or Christian invention. He is neither Justin's puppet nor is he blindly obdurate. Instead he is depicted as a pre-rabbinic Diaspora Jew whose argumentation style is philosophical, even Socratic. The depiction reveals a voice with its own sensibility, style, and agenda. It is a voice which defies fiction.
This process has also caused a reconsideration of the entire text of the Dialogue and its development. This thesis puts forward the hypothesis that within the text of the Dialogue there is a core-text comprised almost exclusively of dialogue material. I have named this hypothetical text the Trypho Text. This reconstructed Trypho Text forms a more cohesive and understandable document than our extant Dialogue and is less than half the size. This thesis provides evidence to support the idea that the Trypho Text comprised what appears to be the core of the original Dialogue (ca. 135 C.E.) with large amounts of LXX and Christian material inserted at a later date (ca.157 C.E.).
In establishing an authentic Jewish figure within this second-century Christian document, this thesis hopes to enhance our understanding of Jewish/Christian relations during this formative period. The investigation of Trypho is an important and significant work for our understanding of early Christianity, Greco-Roman Judaism, and the relationship between them.
Recycling of materials in civil engineering

Although Britain is relatively rich in natural aggregate reserves, planning approvals to develop new quarries are running at about half the rate of aggregate extraction. The use of secondary materials, such as recycled aggregate, might not create a major course of aggregate but if secondary material were used in less demanding situations, the quantity of natural aggregate required by the construction industry would be reduced. This dissertation reports mainly on laboratory tests conducted on crushed concrete and demolition debris to examine the potential use of these materials in new construction. Standard aggregate tests were conducted on the materials to check their compliance with the Specification for Highway Works (1986), particularly for use as aggregate in road sub-base layers. A more detailed examination of the aggregates was conducted with regard to CBR, shear strength and frost susceptibility where the influences of moisture content, density and particle packing on these properties were investigated. One part of the study involved examining the use of recycled aggregate as the coarse aggregate fraction in new concrete. An analysis of the shear strength data was conducted using the dilatancy index defined by Bolton (1986). From the frost susceptibility results, it was concluded that further work would be required in this area to determine the main factors which influence the frost heave of recycled aggregates. The recycled aggregate concrete compared well with the natural aggregate concrete and appeared to be of superior quality than that produced in other research. During the study, it became evident that the recycled aggregates could perform as well as limestone in most cases and therefore could be considered for many potential uses. Some recommendations are presented at the end of this dissertation for the development of a standard on recycled materials which would help to promote the use of recycled aggregates in the construction industry in Britain.

Keywords: concrete
Advisor: Milligan, G
Searches for new physics using Dijet Angular Distributions in proton-proton collisions at √s = 7 TeV collected with the ATLAS detector

Angular distributions of jet pairs (dijets) produced in proton-proton collisions at a centre-of- mass energy √s = 7 TeV have been studied with the ATLAS detector at the Large Hadron Collider using the full 2011 data set with an integrated luminosity of 4.8 fb−1, and reaching dijet masses up to 4.5 TeV. All angular distributions are consistent with QCD predictions.
Analysis of the dijet angular distribution, using a novel technique simultaneously employing the dijet mass, is employed. This analysis is sensitive to both resonant new physics and phenomena with a slow-onset in mass. Using this technique, new exclusion limits have been set at 95% credibility level for several hypotheses of physics beyond the standard model including: quantum gravity scales, with 6 extra dimensions, below 4.11 TeV, quark contact interactions below a compositeness scale of 7.6 TeV, and excited quarks with a mass below 2.75 TeV. In a large and complex scientific experiment, such as ATLAS, the collection, management and usability of coherent data and metadata is a challenging operation. The availability of these data to physicists within the experiment is essential to all analysis efforts. A new web-based interface called “RunBrowser”, which makes ATLAS and LHC operations data available to the ATLAS Collaboration, is introduced.

Keywords: Particle Physics
CERN
Black Holes
Extra Dimensions
Large Hadron Collider
Jets
Advisor: Issever, C
The structural and sedimentological evolution of the Lagonegro zone, Southern Italy

The Lagonegro Zone comprises three structural units which outcrop within the pile of decollement nappes forming the southern Italian Appenines. Stratigraphic, structural and sedimentological evidence suggests that the zone represents the relics of a Mesozoic basin that developed amidst the carbonate platforms bordering the southern margin of Tethys. Mapping has confirmed that the Lagonegro I, Lagonegro II and Monte Foraporta Units are separated by thrusts and are stacked in ascending order. Middle Triassic fine-grained terrigenous clastic sediments and neritic limestone olistoliths of Lagonegro Unit II record the disintegration of a young carbonate platform under the influence of extensional tectonics. Deposition and redeposition of hemi-pelagic lime-mud washed from the adjacent shallow-water platforms during the Late Triassic is manifested in both Lagonegro units by the cherty limestones of the Sirino Formation; a gradual transition from calcareous to siliceous deposition at the top of the formation reflects the subsidence of the basin-floor beneath the Calcite Compensation Depth. Contrasting patterns of siliceous and calciclastic sedimentation developed during the Jurassic, probably imposed by renewed extensional tectonics; coeval calciclastic deposition in a small, and at times anoxic marginal basin is recorded in the Monte Foraporta Unit. Dolomitisation of basinal carbonate rocks took place during the Jurassic due to mixing of saline pore-fluids with meteoric water recharged from the adjacent carbonate platforms. Deposition of terrigenous shales below the Calcite Compensation Depth occurred during the Lower Cretaceous, but calcareous sedimentation was resumed in the Late Cretaceous and Palaeogene. The progressive deepening of the basin documented by these facies transitions is attributed to regional subsidence, caused by crustal extension and attenuation, and relative accretion of the surrounding platforms; comparable basal stratigraphies in several ophiolitic zones of the Alpine-Mediterranean region suggest that many Tethyan 'oceanic' basins may have initially developed in a similar manner.

Advisor: Jenkyns, H
Power to the parents? Participatory governance, civil society, and the quality of democracy in rural Honduras and Guatemala

This thesis examines whether and how participatory governance (PG), a model for incorporating citizen participation in designing and/or implementing strategies to solve public problems, can strengthen civil society and improve the quality of democracy. The study focuses on community-managed schools (CMS) in Honduras and Guatemala, arguably each country's largest PG initiative, in which parents managed rural schools.
This thesis advances a "political capabilities" framework to explore state efforts to strengthen civil society and improve the quality of democracy. I use a mixed-methods approach, centering on surveys of over 2,000 parents and eight community case studies.
My research first shows how different long-standing political legacies—“controlled inclusion” in Honduras and “coerced marginalization” in Guatemala—impinged on CMS. In Honduras, patronage networks captured CMS. In Guatemala, community- and national-level polarization contributed to CMS's reversal. Both undermined the CMS model and reduced the likelihood that participants would develop political capabilities.
Despite these obstacles to stimulating civil society, I find surprising evidence of important individual-level “spillover” effects—such as gaining skills and increasing participation in other organizations—among a non-trivial minority of participating parents. Moreover, regressions and case study analysis indicate that state support, parents' level of involvement, and parents' perceptions of council effectiveness and democraticness can increase the likelihood of certain spillovers.
Still, prior organizational experience remains the best predictor of subsequent participation and leadership. And qualitative analysis further demonstrates the limits of CMS's impacts on rural civil society. For the most part, individuals have not used newly acquired skills to build new types of groups and organize autonomously. Instead, community organizations remain very limited in their scope of action and heavily circumscribed by the state.
In sum, this thesis demonstrates how, through one type of PG initiative, states can stimulate participation and produce changes in individuals’ civic and political behavior. But CMS was not a “game-changer” for rural civil society—the link from incremental changes in individual behavior to how rural communities organize themselves and engage with the state remains tenuous.

Keywords: community-managed schools
participatory governance
quality of democracy
Honduras
Guatemala
civil society
Advisor: Power, T
Essays on human capital formation in developing countries

This thesis consists of a short introduction and three self-contained analytical chapters.
Chapter 1 focuses on the question of learning gaps and divergence in achievement across countries. I use unique child-level panel data from Ethiopia, India, Peru and Vietnam to ask at what ages do gaps between different populations emerge, how they increase or decline over time, and what the proximate determinants of this divergence are. I document that learning gaps between the four countries are already evident at the age of 5 years and grow throughout the age trajectory of children, preserving country ranks from 5 to 15 years of age. At primary school age, the divergence between Vietnam and the other countries is largely accounted for by substantially greater learning gains per year of schooling.
Chapter 2 focuses on learning differences between private and government school students in India. I present the first value-added models of learning production in private and government schools in this context, using panel data from Andhra Pradesh. I examine the heterogeneity in private school value-added across different subjects, urban and rural areas, medium of instruction, and across age groups. Further, I also estimate private school effects on children's self-efficacy and agency. I find modest or insignificant causal effects of attending private schools in most test domains other than English and on children's academic self-concept and agency. Results on comparable test domains and age groups correspond closely with, and further extend, estimates from a parallel experimental evaluation.
Chapter 3 uses panel data from the state of Andhra Pradesh in India to estimate the impact of the introduction of a national midday meal program on anthropometric z-scores of primary school students, and investigates whether the program ameliorated the deterioration of health in young children caused by a severe drought. Correcting for self-selection into the program using a non-linearity in how age affects the probability of enrollment, we find that the program acted as a safety net for children, providing large and significant health gains for children whose families suffered from drought.

Keywords: Human Capital
Economics
Development Economics
Education
Advisor: Dercon, S
Park, A
Capital market imperfections and investment

Recent work in macroeconomics argues that imperfections in capital markets may magnify business cycle fluctuations by propagating relatively modest shocks. This thesis investigates evidence for such a mechanism (also known as the "financial accelerator") by analysing two empirical models of investment in physical capital that test for the importance of capital market imperfections on firms' investment decisions. These models are, respectively, an error correction specification augmented with an additional cash flow term, and an Euler equation model explicitly derived from dynamic optimisation in the presence of symmetric, quadratic costs of adjustment. Chapters 4 and 5 use a large panel of individual Italian manufacturing firms to investigate the impact of capital market imperfections on investment expenditures. Regression results from a system Generalised Method of Moments (GMM) estimator appear to be consistent with the hypothesis that firms that are in a strong informational or liquidity position (large firms, group members, RandD performers) are less likely to face binding financing constraints than firms in a weak informational or liquidity position (small firms, independent firms, non-RandD performers). Investment regressions in Chapter 6, based on consolidated accounting data for three samples of UK, US and Italian companies, show that the sensitivity of investment spending to financial variables is greater in the UK and the US than in Italy. This finding is consistent with the suggestion that outsider control financial systems perform less well in channelling investment funds to firms with profitable investment opportunities than do insider control financial systems. Finally, the empirical analysis in Chapter 7, based on two samples of UK and US firms, provides some preliminary evidence that a less concentrated ownership structure and a high level of institutional ownership may increase the sensitivity of investment to the availability of low-cost internal funds.