VictorJuiz/thesis huggingface dataset:
Operators on banach spaces of Bourgain-Delbaen type
Keywords: Operator Algebras
Banach spaces
Bourgain-Delbaen spaces

The research in this thesis was initially motivated by an outstanding problem posed by Argyros and Haydon. They used a generalised version of the Bourgain-Delbaen construction to construct a Banach space
X
K
for which the only bounded linear operators on
X
K
are compact perturbations of (scalar multiples of) the identity; we say that a space with this property has very few operators. The space
X
K
possesses a number of additional interesting properties, most notably, it has
e
l
l
1
dual. Since
e
l
l
1
possesses the Schur property, weakly compact and norm compact operators on
X
K
coincide. Combined with the other properties of the Argyros-Haydon space, it is tempting to conjecture that such a space must necessarily have very few operators. Curiously however, the proof that
X
K
has very few operators made no use of the Schur property of
e
l
l
1
. We therefore arrive at the following question (originally posed in cite{AH}): must a HI,
m
a
t
h
c
a
l
L
i
n
f
t
y
,
e
l
l
1
predual with few operators (every operator is a strictly singular perturbation of
l
a
m
b
d
a
I
) necessarily have very few operators?
We begin by giving a detailed exposition of the original Bourgain-Delbaen construction and the generalised construction due to Argyros and Haydon. We show how these two constructions are related, and as a corollary, are able to prove that there exists some
d
e
l
t
a
>
0
and an uncountable set of isometries on the original Bourgain-Delbaen spaces which are pairwise distance
d
e
l
t
a
apart.
We subsequently extend these ideas to obtain our main results. We construct new Banach spaces of Bourgain-Delbaen type, all of which have
e
l
l
1
dual. The first class of spaces are HI and possess few, but not very few operators. We thus have a negative solution to the Argyros-Haydon question. We remark that all these spaces have finite dimensional Calkin algebra, and we investigate the corollaries of this result. We also construct a space with
e
l
l
1
Calkin algebra and show that whilst this space is still of Bourgain-Delbaen type with
e
l
l
1
dual, it behaves somewhat differently to the first class of spaces.
Finally, we briefly consider shift-invariant
e
l
l
1
preduals, and hint at how one might use the Bourgain-Delbaen construction to produce new, exotic examples.
Bearing capacity of perforated offshore foundations under combined loading
Keywords: Tresca model
perforated foundations
Bearing capacity
adaptive meshing
combined loading

This thesis presents experimental work and numerical analysis that has been undertaken to assess the bearing capacity of perforated offshore foundations. Perforated foundations may be used to support subsea infrastructure, including as mudmats into which a number of perforations have been made, or as grillages which consist of a series of structurally connected strip footings. Larger gravity base foundations, such as for offshore wind turbines or oil and gas platforms, may adopt a single central perforation. The advantages of using perforated foundations can include reduced material requirements and easier offshore handling as a result of smaller weight and lower hydrodynamic forces during deployment. Limited guidance currently exists for assessing the bearing capacity of these foundation types.
Bearing capacity of perforated foundations has been examined in this thesis under conditions of combined vertical, horizontal and moment loading which is typical in offshore settings. Undrained soil conditions have been considered, except for the case of grillages in which drained conditions are often most relevant. Experimental work has included centrifuge testing of ring and square annular foundations on clay, and 1g testing of grillage foundations on sand. Finite element modelling has also been undertaken to assess perforated foundation capacity. A Tresca material subroutine (UMAT) and an adaptive meshing scheme have been developed to improve the accuracy of the finite element analysis carried out.
The results showed that perforated foundations can be an efficient foundation solution for accommodating combined loading. As a ratio of their vertical load capacity, perforated foundations may be able to withstand higher moment and horizontal loads compared with unperforated foundations. The experimental and numerical results have been used to develop design expressions that could be employed by practitioners to estimate the vertical and combined load bearing capacity of these foundation types.
Discourse analysis of emissions trading scholarship
Keywords: law
discourses
emissions trading
states
markets

Over the last four decades emissions trading has enjoyed a high profile in environmental law scholarship and in environmental law and policy. Much of this regulatory discussion is promotional, preferring emissions trading above other regulatory strategies without, however, engaging with legal complexities embedded in conceptualising, scrutinising and managing emissions trading schemes. The combined effect of these debates is to create a perception that emissions trading is a straightforward regulatory strategy, imposable across various jurisdictions and environmental settings. This thesis shows that this view of emissions trading is problematic for at least two reasons. First, emissions trading responds to distinct environmental and non-environmental goals, including creating profit-centres, establishing a governance regime aimed at substituting state control of common resources, and ensuring regulatory compliance. This is important, as the particular purpose entrusted to a given emissions trading regime has, as its corollary, a particular governance structure, according to which the regime may be constructed and managed. Second, the governance structures of emissions trading regimes are culture- specific, which is a significant reminder of the importance of law in understanding not only how emissions trading schemes function but also what meaning is given to them as regulatory strategies. This is shown by deconstructing emissions trading discourses: that is, by inquiring into the assumptions about emissions trading that feature in the literature and in debates involving law- and policymakers and the judiciary at the EU level. Ultimately, this thesis makes a strong argument for reconfiguring the common understanding of emissions trading schemes as regulatory strategies, and sets out a framework for analysis to sustain that reconfiguration.
Active faulting and deformation of the Mongolian Altay mountains
Keywords: geochronology
earth sciences
active tectonics
faulting and earthquakes

In this thesis, I use multiple techniques to investigate the active faulting and deformation of the Altay Mountains, Western Mongolia. The Altay are an intracontinental transpressional mountain range, which are deforming in the far-field of the India-Asia collision. An anastomosing network of dextral faults strikes NNW-SSE, and accommodates NE-SW oriented shortening by rotating anticlockwise about vertical axes. I begin by characterising the Altay faults, and add to what is already known about their surface expression with new observations of active faulting and three previously undescribed ancient earthquake ruptures. I use 10Be cosmogenic dating and uranium-series dating on pedogenic carbonate to estimate the average Quaternary rate of slip for two of the major fault zones in the Altay. The slip rate on the Ölgiy fault is constrained to 0.3-2.1 mm/yr-1. Results from the Hovd fault are ambiguous, demonstrating the complications encountered with application of Quaternary dating techniques. I measure palaeomagnetic directions from Cretaceous to Pliocene-aged sediments in the eastern Altay to constrain the degree of anticlockwise rotation. Results from thermal demagnetisation of specimens indicate that the eastern Altay has not undergone significant rotation, in contrast with previous studies from the Siberian Altay that reveal almost 40 degrees of anticlockwise rotation. This suggests that the eastern-most Altay fault is too young to have experienced significant rotation, or is kinematically different from the Siberian Altay. I apply apatite fission track (AFT) dating and track length modeling to the central Altay. Results from AFT dating show rapid cooling in the late Cretaceous due to the distal assembly of Central Asia, suggesting that there was pre-existing topography at the start of the Late Cenozoic phase of deformation, the timing of which is constrained to have initiated at least 20 Myr ago. My work demonstrates that combining results from techniques that cover a variety of time scales quantifies the evolution of active faulting and deformation in the region.
A situational understanding of friendship networks
Keywords: friendship networks
stochastic actor-oriented models
social network analysis

The structure of social networks, and people's position within these networks, are important predictors of many individual and group-level outcomes. One type of social networks that is regularly studied are the mutually interdependent relations of friends. This thesis focusses on friendship networks between adolescents in the context of schools.
Arguably the most important and consistently found regularities in adolescent friendship networks are i) the tendency of friendships to be mutual, called reciprocity; ii) their tendency to cluster in groups, known as transitivity; and iii) the tendency of friendships to be present between those that are similar to one another, called homophily. Various social theories originating in different disciplines have theoretically proposed and empirically found micro-mechanisms that explain the regular occurrence of these substructures in friendship networks. This thesis introduces a framework of how the relation between these different networks tendencies can be understood.
I propose that each of the three network evolution mechanisms can be connected to a type of social situation in which friends interact to form and maintain their friendships. Social situations that are dyadic and only involve two persons are connected to reciprocal friendships. Group-based social situations, on the other hand, are related to transitivity and homophily, where the groups are either defined socially or through common characteristics. Starting from this proposition, I suggest that when two adolescents share one forum for interaction with one another, i.e. they regularly meet within one of the social situations, meeting in additional other situations does not increase the likelihood of a friendship tie existing as much as could be expected from the sum of the effect of meeting in either situation. Consequently, I expect a negative interaction between the different network mechanisms.
After a series of empirical analyses that support the outlined reasoning, I use the developed perspective to investigate how the micro-mechanisms contribute differentially to the creation of newly formed friendships and to the maintenance of already existing friendships. Finally, I show how a situational understanding of friendship can be used to differentiate which friendships are most important for social influence and for peer pressure.
Investigating magnetism and superconductivity using high magnetic fields
Keywords: superconductivity
high pressure
proximity detector oscillator
pnictide
high magnetic fields
molecular magnets

This thesis investigates a number of transition-metal coordination polymers and iron-pnictide superconductors through the use of high magnetic fields, low temperatures, and on occasion, high pressures.
The thesis will begin by describing my development of the proximity detector dynamic susceptometer, a novel technique that can be used for magnetometery and transport measurements in high magnetic fields. This technique is highly compact and has no moving parts, making it suitable for use in pressure cells, hence opening the way for a variety of new experiments.
Through high-field magnetometery and other measurements, I will demonstrate that the pressure can be used to directly control the magnetic properties of the polymeric magnet CuF2(H2O)2(pyrazine). In particular, I observe a transition from quasi-two-dimensional to quasi-one-dimensional antiferromagnetism at 9~kbar, driven by the rotation of the Jahn-Teller axis.
I will then present a series of measurements on two coordination polymers, showing how a small chemical difference can lead to drastically different magnetic properties. I show that [Cu(pyrazine)H2O(glycine)2]ClO4 is an excellent spin-chain, while the sister compound [Cu(pyrazine)(glycine)]ClO4 is a dimerised material that shows a spin-gap and is disordered down to very low temperatures, but then undergoes a field-induced phase transition to an ordered phase.
I will also describe a series of pulsed-field measurements of the upper critical field of the iron-based superconductors NaFe1-xCoxAs across the whole of the doping phase diagram. It is shown that paramagnetic pair-breaking effects dominate the critical field when the field is parallel to the crystal planes. In the parent compound the paramagnetic limit is equal to that expected from BCS theory, but becomes significantly enhanced above the BCS limit upon doping. It is shown that the multi-band nature of the superconductivity leads to a convex curvature in the evolution of the critical field as the temperature is reduced.
Transmission electron imaging and diffraction characterisation of 2D nanomaterials
Keywords: electron microscopy; 2D nanomaterials

Following the discovery of graphene, 2D nanostructures have been noted for their potential in a range of high-impact applications, such as sensing, catalysis, and composite reinforcement. Liquid-phase exfoliation and chemical vapour deposition have been demonstrated and indicate the feasibility of mass-scale production. With the advent of mass-produced 2D nanostructures a key focus of research is to characterise these materials.
This thesis is concerned with imaging and structural properties of the 2D nanomaterials, hexagonal boron nitride (h-BN), molybdenum disulfide (MoS2), tungsten disulfide (WS2), titanium disulfide (TiS2) and hexabenzocoronene (HBC), produced via liquid phase exfoliation. HBC strictly speaking is not 2D nanomaterial, however, it can be viewed as transition molecule from benzene to graphene. The data used for characterisation is based primarily on electron diffraction and, in particular, aberration corrected annular dark field (ADF) scanning transmission electron microscopy (STEM). The incoherent nature of ADF STEM provides direct atomic imaging without the contrast reversals upon focus changes seen in conventional high-resolution transmission electron microscopy (HRTEM).
The main structural feature investigated in this thesis was the stacking sequences in few-layers h-BN, MoS2, WS2 and TiS2. Simple stacking (AAA) can be distinguished from Bernal (ABA) and rhombohedral (ABC) on the basis of intensity ratio, I{10̅10}/I{11̅20} , in diffraction patterns and indirectly in HRTEM images. Nonetheless acquisition of the diffraction patterns suitable for analysis can be challenging due to the sample issues. Non-bulk stacking sequences were reliably confirmed for all above 2D nanomaterials on the basis of atomically resolved ADF STEM. 20 h-BN, 28 MoS2, 5 WS2 and 6 TiS2 nanoflakes were imaged and analysed. Amongst them 2 h-BN, 9 MoS2, 4 WS2 and 1 TiS2 nanoflakes displayed non-bulk stacking. Hence, it appears that 2D WS2 has the greatest affinity for non-bulk stacking.
Finally, an interesting structural transformation was observed in HBC molecules. Under the influence of electron beam HBC agglomerates were transformed into crystalline phase with 90o symmetry
Equations for modular curves
Keywords: Modular curves

The primary topic of this thesis is the construction of explicit projective equations for the modular curves X0(N)
. The techniques may also be used to obtain equations for X
+
0
(p)
and, more generally, X0(N)/Wn
. The thesis contains a number of tables of results. In particular, equations are given for all curves X0(N)
having genus 2legle5
. Equations are also given for all X
+
0
(p)
having genus 2 or 3, and for the genus 4 and 5 curves X
+
0
(p)
when ple251
. The most successful tool used to obtain these equations is the canonical embedding, combined with the fact that the differentials on a modular curve correspond to the weight 2 cusp forms. A second method, designed specifically for hyperelliptic curves, is given. A method for obtaining equations using weight 1 theta series is also described.
Heights of modular curves are studied and a discussion is given of the size of coefficients occurring in equations for X0(N)
.
Finally, the explicit equations are used to study the rational points on X
+
0
(p)
. Exceptional rational points on X
+
0
(p)
are exhibited for p=73,103,137
and 191.
An investigation of clemency and pardons in death penalty cases in Southeast Asia from 1975-2009
Keywords: Southeast Asia
death penalty
comparative criminal justice
capital punishment

Four of the contemporary practitioners of the death penalty in Southeast Asia: Indonesia, Malaysia, Thailand and Singapore, performed judicial executions on a regular basis between the years 1975 and 2009. Notwithstanding this similarity, the number of death sentences passed by courts that were subsequently reduced to a term of imprisonment through grants of clemency by the executive (or where the prisoner sentenced to death is exonerated by way of a pardon) varied remarkably between these jurisdictions over this 35-year period: some of these countries commuted the sentences of death row prisoners often, others rarely. In this DPhil thesis, I employ the methodology of comparative criminal justice to explore the discrepancies and similarities in capital clemency practice between these four Southeast Asian jurisdictions, seeking to document the known examples of clemency grants over the course of their modern history, and to investigate the reasons why retentionist countries exercise clemency at vastly different ‘rates’ in finalised capital cases.
As clemency and pardon deliberations by the executive are usually performed in secret, academic study of the subject has remained scarce, and the suspected reasons behind death sentence commutations, and their relative frequency, are rarely analysed. My inductive, qualitative study in comparative criminal justice will attempt to address these deficiencies in analysis as they apply to four Southeast Asian countries that continue to practice capital punishment as a form of criminal sanction. Moving beyond Amnesty International’s simplistic observation that ‘nowhere in Asia has the ready availability of such clemency been marked’, I examine the intricacies of the clemency practice in each jurisdiction, and arrive at regional trends and patterns.
Adaptive mesh modelling of the thermally driven annulus
Keywords: dynamic mesh adaptivity
geostrophic balance
rotating annulus
finite element method

Numerical simulations of atmospheric and oceanic flows are fundamentally limited by a lack of model resolution. This thesis describes the application of unstructured mesh finite element methods to geophysical fluid dynamics simulations. These methods permit the mesh resolution to be concentrated in regions of relatively increased dynamical importance. Dynamic mesh adaptivity can further be used to maintain an optimised mesh even as the flow develops. Hence unstructured dynamic mesh adaptive methods have the potential to enable efficient simulations of high Reynolds number flows in complex geometries.
In this thesis, the thermally driven rotating annulus is used to test these numerical methods. This system is a classic laboratory scale analogue for large scale geophysical flows. The thermally driven rotating annulus has a long history of experimental and numerical research, and hence it is ideally suited for the validation of new numerical methods.
For geophysical systems there is a leading order balance between the Coriolis and buoyancy accelerations and the pressure gradient acceleration: geostrophic and hydrostatic balance. It is essential that any numerical model for these systems is able to represent these balances accurately. In this thesis a balanced pressure decomposition method is described, whereby the pressure is decomposed into a
balanced'' component associated with the Coriolis and buoyancy accelerations, and a
residual'' component associated with other forcings and that enforces incompressibility. It is demonstrated that this method can be used to enable a more accurate representation of geostrophic and hydrostatic balance in finite element modelling. Furthermore, when applying dynamic mesh adaptivity, there is a further potential for imbalance injection by the mesh optimisation procedure. This issue is tested in the context of shallow-water ocean modelling. For the linearised system on an f
-plane, and with a steady balance permitting numerical discretisation, an interpolant is formulated that guarantees that a steady and balanced state remains steady and in balance after interpolation onto an arbitrary target mesh.
The application of unstructured dynamic mesh adaptive methods to the thermally driven rotating annulus is presented. Fixed structured mesh finite element simulations are conducted, and compared against a finite difference model and against experiment. Further dynamic mesh adaptive simulations are then conducted, and compared against the structured mesh simulations. These tests are used to identify weaknesses in the application of dynamic mesh adaptivity to geophysical systems. The simulations are extended to a more challenging system: the thermally driven rotating annulus at high Taylor number and with sloping base and lid topography. Analysis of the high Taylor number simulations reveals a direct energy transfer from the eddies to the mean flow, confirming the results of previous experimental work.
Out of harm's way: understanding kidnapping in Mexico City 
Keywords: rule of law
trust
kidnapping
signaling
Mexico
sociology
Mexico City
crime

This dissertation analyses the survival strategies that wealthy people in Mexico City have designed and implemented to protect themselves from kidnapping with special focus on household employment relationships. This particular crime has demonstrated a particular evolution in the last 20 years that deserves analysis. Once a political crime, it became an economic crime that at first only targeted wealthy individuals and then over time began targeting working class victims. Based on extensive qualitative fieldwork in Mexico City which included a year in the field, 78 interviews with employers, employees, kidnapping victims and members of the police forces and justice system and the creation of a news reports database this thesis presents a detailed history of the evolution of kidnapping in the period 1968-2009. This is followed by an in depth analysis of the strategies elites use to protect themselves from this crime. Special attention is focused on the hiring process of household employees, namely drivers, as evidence suggests that most kidnappings are organized or facilitated in some way by a close collaborator of the victim. The hiring process is approached as a problem of trust. Signaling theory is the main framework used for the solving of this problem, as well as some ideas found in transaction cost economics, namely vertical integration. The results point towards strategic behavior from the actors involved that seeks to minimize the risk of being kidnapped for the employer. Signaling helps us uncover the specific mechanisms by which employer establish their prospective employees’ trustworthiness. The use of informal social networks made up of strong ties is one of the most salient mechanisms used to guarantee honest employees and this, together with a composite set of properties is signaled throughout. This thesis contributes to the literature on crime in Latin America as well as to the sociological literature on signaling, a branch of analytical sociology.