VictorJuiz/thesis huggingface dataset:
Pax terra mariqve: rhetorics of Roman victory, 50 B.C. -  A.D. 14

This thesis focuses on a short period of time between 50 B.C. to A.D. 14, which is marked by the increased prominence of pax as a central concept within the victory rhetoric of the period. The period is one of immense political and social upheaval and change that was to dictate the power structures of the Roman world, and one of the ways in which this change was conceptualised was through the language of peace.
In this thesis I examine pax as a concept within the Roman empire and as part of an discourse on the nature of Roman imperialism. This examination considers not just the development of pax as a concept over time, but also how it was variously conceptualised and presented to different audiences and in different locations. This focuses the examination of pax on understanding what the term as an expression of Rome’s imperium meant to various peoples within the Roman empire, how it was expressed and for what reasons. As David Mattingly has recently emphasised the nature of Roman imperialism changed radically over time (‘Imperialism, Power, and Identity: Experiencing the Roman Empire’ (2011)). This study of the different rhetorics of peace offers new insight into this changing nature.
Beyond the specific examination of pax as a part of imperial discourse within the late Republic and early Principate, this study raises questions about the way we think about concepts in the ancient world. Rather than talking about a single development or evolution over time, we should rather consider concepts as constantly active and changing in time. Our view of the ancient world and the way in which it was conceptualised should not be a static one, but one where the meaning and value of words give us insights into how individuals and communities expressed and explained changing social and political conditions.

Keywords: War
Roman Imperialism
Peace
Roman History
Advisor: Quinn, J
G2 geometry and integrable systems

We study the Hitchin component in the space of representations of the fundamental group of a Riemann surface into a split real Lie group in the rank 2 case. We prove that such representations are described by a conformal structure and class of Higgs bundle we call cyclic and we show cyclic Higgs bundles correspond to a form of the affine Toda equations. We also relate various real forms of the Toda equations to minimal surfaces in quadrics of arbitrary signature. In the case of the Hitchin component for PSL(3,R) we provide a new proof of the relation to convex RP²-structures and hyperbolic affine spheres. For PSp(4,R) we prove such representations are the monodromy for a special class of projective structure on the unit tangent bundle of the surface. We prove these are isomorphic to the convex-foliated projective structures of Guichard and Wienhard. We elucidate the geometry of generic 2-plane distributions in 5 dimensions, work which traces back to Cartan. Nurowski showed that there is an associated signature (2,3) conformal structure. We clarify this as a relationship between a parabolic geometry associated to the split real form of G₂ and a conformal geometry with holonomy in G₂. Moreover in terms of the conformal geometry we prove this distribution is the bundle of maximal isotropics corresponding to the annihilator of a spinor satisfying the twistor-spinor equation. The moduli space of deformations of a compact coassociative submanifold L in a G₂ manifold is shown to have a natural local embedding as a submanifold of H2(L,R). We consider G2-manifolds with a T^4-action of isomorphisms such that the orbits are coassociative tori and prove a local equivalence to minimal 3-manifolds in R^{3,3} = H²(T⁴,R) with positive induced metric. By studying minimal surfaces in quadrics we show how to construct minimal 3-manifold cones in R^{3,3} and hence G₂-metrics from equations that are a set of affine Toda equations. The relation to semi-flat special Lagrangian fibrations and the Monge-Ampere equation is explained.

Keywords: 53C38
Hitchin component
53C07
G2
53C29
parabolic geometry
special Lagrangian
coassociative
Higgs bundles
53C43
Advisor: Hitchin, N
Asymptotic invariants of infinite discrete groups

Asymptotic cones. A finitely generated group has a word metric, which one can scale and thereby view the group from increasingly distant vantage points. The group coalesces to an "asymptotic cone" in the limit (this is made precise using techniques of non-standard analysis). The reward is that in place of the discrete group one has a continuous object "that is amenable to attack by geometric (e.g. topological, infinitesimal) machinery" (to quote Gromov).
We give coarse geometric conditions for a metric space X to have N-connected asymptotic cones. These conditions are expressed in terms of certain filling functions concerning filling N-spheres in an appropriately coarse sense.
We interpret the criteria in the case where X is a finitely generated group Γ with a word metric. This leads to upper bounds on filling functions for groups with simply connected cones -- in particular they have linearly bounded filling length functions. We prove that if all the asymptotic cones of Γ are N-connected then Γ is of type FN+1 and we provide N-th order isoperimetric and isodiametric functions. Also we show that the asymptotic cones of a virtually polycyclic group Γ are all contractible if and only if Γ is virtually nilpotent.
Combable groups and almost-convex groups. A combing of a finitely generated group Γ is a normal form; that is a choice of word (a combing line) for each group element that satisfies a geometric constraint: nearby group elements have combing lines that fellow travel. An almost-convexity condition concerns the geometry of closed balls in the Cayley graph for Γ.
We show that even the most mild combability or almost-convexity restrictions on a finitely presented group already force surprisingly strong constraints on the geometry of its word problem. In both cases we obtain an n! isoperimetric function, and upper bounds of ~ n2 on both the minimal isodiametric function and the filling length function.

Keywords: group
combing
isoperimetric inequality
asymptotic cone
Advisor: Bridson, M
La Tène and early Gallo-Roman north-west France

The basis of this research is the compilation of a gazetteer of sites and finds of the La Tène and early Gallo-Roman periods (c. 475 BC - c. 31 BC) in north-west France. Two aspects of the evidence thus collected are examined in detail: settlement and coinage.
For the early La Tène period, burial evidence provides the only significant source of information, and at present it is not of sufficient quality or quantity to do more than shed light on a few specific aspects of regional development. Similarly, the settlement evidence from the later periods is also relatively scarce. However the introduction of coinage in the middle La Tène, probably via mercenaries returning from service in the Greek world, provides a much more substantial body of information on developments between the third and first centuries BC. Following a consideration of the theoretical aspects of coin use and function, all the major types of coinage in north-west France are examined in detail, and a number of problems of attribution and interpretation are discussed.
It is apparent from the study of settlement and coinage that several traditional interpretations of aspects of the La Tène and early Gallo-Roman periods in north-west France need to be reassessed, in particular questions concerning the development of oppida, and the function of coinage. In the concluding chapter a model of the development of coinage in the region is suggested, illuminated where possible by the application of settlement evidence. The result demonstrates clearly the extraordinarily cohesive nature of this area, which has been termed "greater Armorica", throughout the later Iron Age and into the Gallo-Roman era.
Variable domain orientations in antigen receptors

Specific recognition of pathogenic molecules by the immune system is mediated by proteins known as antigen receptors. One such component is the antibody. Binding properties of natural and engineered antibodies can be understood by studying the structure of their variable domains, VH and VL. In this thesis we investigate how the two variable domains orientate with respect to one another and therefore influence the geometry of the antigen binding site which is formed between them.
We describe a method which fully characterises the VH-VL orientation in a consistent and absolute sense using five angles and a distance. The ABangle method is used to investigate variable domain orientation in structures collected by our database SAbDab.
Using the ABangle method we compare VH-VL orientation to the corresponding property in a different component of the immune system, the T-cell receptor (TCR). Despite having similar individual domain structures the variable domain orientations of antibodies and TCRs are found to be distinct. This is found to affect an antibody’s ability to mimic TCR specificity.
ABangle's characterisation is used to find determinants of the VH-VL orientation. We identify sequence and structural properties that influence the variable domain pose. A feature based method for predicting VH-VL orientation is presented and assessed. Future directions of this research and its application to the development of antibody therapeutics are described.

Keywords: Protein Engineering
Structural Biology
Computational Biology
Antibodies
Advisor: Deane, C
Fuchs, A
Shi, J
Special metric structures and closed forms

In recent work, N. Hitchin described special geometries in terms of a variational problem for closed generic p
-forms. In particular, he introduced on 8-manifolds the notion of an integrable PSU(3)
-structure which is defined by a closed and co-closed 3-form. In this thesis, we first investigate this PSU(3)
-geometry further. We give necessary conditions for the existence of a topological PSU(3)
-structure (that is, a reduction of the structure group to PSU(3)
acting through its adjoint representation). We derive various obstructions for the existence of a topological reduction to PSU(3)
. For compact manifolds, we also find sufficient conditions if the PSU(3)
-structure lifts to an SU(3)
-structure. We find non-trivial, (compact) examples of integrable PSU(3)
-structures. Moreover, we give a Riemannian characterisation of topological PSU(3)
-structures through an invariant spinor valued 1-form and show that the PSU(3)
-structure is integrable if and only if the spinor valued 1-form is harmonic with respect to the twisted Dirac operator. Secondly, we define new generalisations of integrable G2
- and Spin(7)
-manifolds which can be transformed by the action of both diffeomorphisms and 2-forms. These are defined by special closed even or odd forms. Contraction on the vector bundle ToplusT∗
defines an inner product of signature (n,n)
, and even or odd forms can then be naturally interpreted as spinors for a spin structure on ToplusT∗
. As such, the special forms we consider induce reductions from Spin(7,7)
or Spin(8,8)
to a stabiliser subgroup conjugate to G2timesG2
or Spin(7)timesSpin(7)
. They also induce a natural Riemannian metric for which we can choose a spin structure. Again we state necessary and sufficient conditions for the existence of such a reduction by means of spinors for a spin structure on T
. We classify topological G2timesG2
-structures up to vertical homotopy. Forms stabilised by G2timesG2
are generic and an integrable structure arises as the critical point of a generalised variational principle. We prove that the integrability conditions on forms imply the existence of two linear metric connections whose torsion is skew, closed and adds to 0. In particular we show these integrability conditions to be equivalent to the supersymmetry equations on spinors in supergravity theory of type IIA/B with NS-NS background fields. We explicitly determine the Ricci-tensor and show that over compact manifolds, only trivial solutions exist. Using the variational approach we derive weaker integrability conditions analogous to weak holonomy G2
. Examples of generalised G2
- and Spin(7)
structures are constructed by the device of T-duality.

Keywords: special metrics
skew-torsion
G2
sugra compactifications
generalised geometry
Advisor: Hitchin, N
The role of catalysts and algae in forming a sustainable solution for a global food and fuel crisis

This thesis undertakes three separate lifecycle analyses to determine the emissions and fossil energy demand required to process algae biomass into renewable fuel and animal feed. A complete well-to-wheel fuel-cycle analysis is conducted for the production of biodiesel and jet biofuel from algae biomass. The environmental impacts of algae-based fuels for the road transportation and aviation industry are benchmarked against analogue conventional fossil fuels. This thesis demonstrates that algae biofuel production can only realize its inherent environmental advantage of reduced GHG emissions, once every step of the production chain is fully optimized and decarbonized. This includes smart co-product utilization, offsetting fertilizers through wastewater recycling, reusing exhaust gases as additional CO2 source and using decarbonized electricity, heat and indirect energy.
The definition of a Catalyst Sensitivity Index (CSI) demonstrates how catalytic efficiency increases can impact the fossil energy consumption and the greenhouse gas emissions balance of catalyst-dependent processes. The CSI will allow the industry to highlight ‘best practice catalysts’ and draw conclusions for what efficiency gains one could anticipate with higher performance catalysts.
For countries where a decarbonized electricity and heat grid is not available to guarantee low-carbon algae fuel production and the looming resource scarcity around marine feed production has become more pressing, the alternative use of algae for aquafeed production is recommended. This thesis analyses major routes towards the future cost-competitive production of microbial biomass as sustainable fish meal and oil source to meet a global demand for depleting fish feed supplies. A comprehensive economic cost analysis and lifecycle assessment demonstrates the feasibility of replacing global fish meal and fish oil supplies with low-carbon and affordable algae feed by the year 2030. This research reveals how algae feed production has the potential to transform a pressing resource tipping point into a turning point.

Keywords: catalysis
biofuels
algae
lifecycle analysis
transport
low carbon
energy security
climate change
Advisor: King, D
Edwards, P
Long-term forest dynamics in high-altitude mountains of West-Central Mexico

This thesis presents the results of a study to examine long-term forest dynamics in the high-altitude mountains of West-Central Mexico. Vegetation dynamics on temporal scales ranging from 102 to 103 years were reconstructed in order to provide essential information on the temporal variability of ecological patterns and processes in these forests; information that is of direct relevance for their current and future conservation and management strategies.
Vegetation and palaeoecological methods undertaken included fossil and modern pollen analysis, vegetation surveys, microfossil charcoal analysis, magnetic susceptibility, inorganic and organic geochemistry, radiocarbon and 210Pb dating. These were used to evaluate the long-term dynamics of three forest types; Pine Forest, Cloud Forest and Transitional Forest on timescales spanning the past 4260, 1340 and 1230 years respectively.
The main drivers of change were climate and disturbance events induced by climate fluctuations, for example increased fire frequency. The reconstructed records indicate that the sequences from the Cloud Forest and the Transitional Forest spanned two wet and one dry climatic interval while the Pine Forest sequence spanned two dry and two wet periods. The impact of these climatic fluctuations was significant on all three forest types and resulted in variations in forest diversity, taxonomic turnover and successional change. The climate change episodes observed in these records seem to be the local manifestation of climatic events that were occurring throughout Mexico at these intervals in time. Human influences were evident in the three forests through the appearance of cultural taxa, particularly during the driest period (~ 1200 yr BP). There is little evidence from these records, however, to suggest a widespread clearance of the landscape for agriculture.
Results from this study support the current conservation and management recommendations for Cloud Forest to exclude timber extraction, grazing and agricultural activities from this forest type. In the Pine Forest, human interventions such small-scale agriculture, prescribed burning and silvicultural actions are in agreement with the longterm pine ecology and as such, total exclusion of human activities is not necessary. For the Transitional Forest, results from this study suggest that there needs to be the establishment of adequate plans to reduce frequent fires to arrest the development of prone-to-fire taxa.

Advisor: Willis, K
Pathogen identification in lower respiratory tract infection

Treatment of lower respiratory tract infection (pneumonia and pleural infection) relies on the use of empirical broad spectrum antibiotics, primarily because reliable pathogen identification occurs infrequently. Another consequence of poor rates of pathogen identification is that our understanding of the microbiology of these infections is incomplete.
This thesis addresses some of these issues by combining the acquisition of high quality lower respiratory tract samples, free from nasooropharyngeal contamination, with novel molecular microbiological techniques in an attempt to increase rates of pathogen identification.
Four main areas are examined;
The role of so-called ‘atypical pneumonia’ bacteria in causing pleural infection. These pathogens have been previously identified in the pleural space infrequently and routine culture usually fails to isolate such bacteria. High sensitivity nested polymerase chain reaction (PCR) is a culture-independent technique which is used to undertake a systematic evaluation for these pathogens in pleural infection samples.
The role of Pneumocystis jirovecii in pleural infection, either as a co-infecting pathogen or in monomicrobial infection. This fungus causes severe pneumonia, particularly in the immunosuppressed, but is increasingly recognised as a co-pathogen in community-acquired pneumonia, and is frequently isolated in the upper and lower respiratory tract in health. A high sensitivity real-time PCR assay is used to examine for this fungus.
Ultra-deep sequencing of the 16S rRNA gene is used to perform a comprehensive microbial survey in samples taken from the multi-centre MIST2 study of pleural infection. The techniques employed allow analysis of polymicrobial samples and give very high taxonomic resolution, whilst incorporating methods to control for potential contamination. Further, these techniques provide confirmation of the results from the ‘atypical’ bacteria nested PCR study.
Bedside ultrasound-guided percutaneous transthoracic needle aspiration (TNA) of consolidated lung is undertaken in patients with pneumonia, as part of the PIPAP study. An evaluation is undertaken of the efficacy and acceptability of TNA. Aspirate samples acquired are also processed using ultra-deep sequencing of the 16S rRNA gene. Other samples obtained as part of the PIPAP study, such as ‘control’ lung aspirates and ‘control’ pleural fluid samples, are similarly processed to enable calculation of sensitivity and specificity of the sequencing methodology.

Keywords: empyema
diagnostics
pneumonia
16S rRNA
microbiology
pleural infection
Advisor: Crook, D
Chapman, S
Davies, R
Development of superconducting bolometer device technology for millimeter-wave cosmology instruments

The Cold-Electron Bolometer (CEB) is a sensitive detector of millimeter-wave radiation, in which tunnel junctions are used as temperature sensors of a nanoscale normal metal strip absorber. The absorber is fed by an antenna via two Superconductor-Insulator-Normal metal (SIN) tunnel junctions, fabricated at both ends of the absorber. Incoming photons excite electrons, heating the whole electron system. The incoming RF power is determined by measuring the tunneling current through the SIN junctions. Since electrons at highest energy levels escape the absorber through the tunnel junctions, it causes cooling of the absorber. This electron cooling provides electro-thermal feedback that makes the saturation power of a CEB well above that of other types of millimeter-wave receivers. The key features of CEB detectors are high sensitivity, large dynamic range, fast response, easy integration in arrays on planar substrates, and simple readout. The high dynamic range allows the detector to operate under relatively high background levels.
In this thesis, we present the development and successful operation of CEB, focusing on the fabrication technology and different implementations of the CEB for efficient detection of electromagnetic signals. We present the CEB detector integrated across a unilateral finline deposited on a planar substrate. We have measured the finline-integrated CEB performance at 280-315 mK using a calibrated black-body source mounted inside the cryostat. The results have demonstrated strong response to the incoming RF power and reasonable sensitivity. We also present CEB devices fabricated with advanced technologies and integrated in log-periodic, double-dipole and cross-slot antennas. The measured CEB performance satisfied the requirements of the balloon-borne experiment BOOMERANG and could be considered for future balloon-borne and ground-based instruments.
In this thesis we also investigated a planar phase switch integrated in a back-to-back finline for modulating the polarization of weak electromagnetic signals. We examine the switching characteristics and demonstrate that the switching speed of the device is well above the speed required for phase modulation in astronomical instruments. We also investigated the combination of a detector and a superconducting phase switch for modulating the polarization of electromagnetic radiation.

Keywords: device technology
nanotechnology
lithography
microwave
microfabrication
modelling
millimeter-wave
quantum device physics
detectors
astrophysics
integrated circuit
Advisor: Yassin, G