VictorJuiz/thesis huggingface dataset:
Placed deposits in early and middle Anglo-Saxon rural settlements

Placed deposits have received increasing attention over the past 30 years, particularly in prehistoric British archaeology. Although disagreement still exists over the definition, identification, and interpretation of placed deposits, significant advances have been made in theoretical and methodological approaches to placed deposits, as researchers have gradually moved away from relatively crude ‘ritual’ interpretations toward more nuanced considerations of how placed deposits may have related to daily lives, social networks, and settlement structure, as well as worldview. With the exception of comments on specific deposits and a recent preliminary survey, however, Anglo-Saxon placed deposits have remained largely unstudied.
This thesis represents the first systematic attempt to identify, characterize, analyse and interpret placed deposits in early to middle Anglo-Saxon settlements (5th–9th centuries). It begins by disentangling the various definitions of ‘placed’, ‘structured’, and ‘special’ deposits and their associated assumptions. Using formation process theory as a basis, it develops a definition of placed deposits as material that has been specially selected, treated, and/or arranged, in contrast with material from similar or surrounding contexts. This definition was applied to develop contextually specific criteria for identifying placed deposits in Anglo-Saxon settlements.
Examination of 141 settlements identified a total of 151 placed deposits from 67 settlements. These placed deposits were characterized and analysed for patterns in terms of material composition, context type, location within the settlement, and timing of deposition relative to the use-life of their contexts. Broader geographical and chronological trends have also been considered. In discussing these patterns, anthropological theories of action, agency, practice, and ritualization have been employed in order to begin to understand the roles placed deposits may have had in structuring space and time and expressing social identities in Anglo-Saxon settlements, and to consider how placed deposition may have articulated with Anglo-Saxon worldview and belief systems.

Keywords: Anglo-Saxons
offerings
votive deposits
archaeology
ritual
rural settlement
placed deposits
lifecycle
social life
liminality
rites
early medieval
boundaries
structured deposits
England
Advisor: Hamerow, H
Protectionism and agricultural commodity trade

This study has two main objectives. The first is to investigate the capacity and limits of spatial equilibrium modelling in the context of international agricultural commodity trade. The second is to identify protectionism and other factors distorting the pattern of trade in an international agricultural commodity market and to assess their relative importance. Wheat is chosen as the commodity of study.
It is shown how various distorting factors can be built into a basic model whose predictions as a result grow closer and closer to observed reality. The closeness of fit of the model to reality is measured by use of a simple statistic (called λ). Moreover, as the model is built up, the trade flow matrix shows where distortions lie, and what the success of particular model alterations are in capturing the nature of these distortions.
Protectionism is found to be the most significant cause of distortion in the international wheat market. In some cases, however, in particular the US Export Enhancement Program, it appears to be counter-distortionary i.e. redressing distortions on trade patterns caused by other protectionist policies. Also, the effects of including in the model countries additional to those in the basic model are analysed, and a comparison with the international soya market is made.
Two-photon dyes for biological application

Two photon absorption (TPA) is the near simultaneous absorption of two photons of light to achieve an electronically excited state. It has led to huge advances in microscopy and microfabrication due to its quadratic dependence on the local light intensity. This thesis describes the design, synthesis and application of dyes with strong TPA properties, and as such is divided into three chapters. The first introduces the theory and measurement of TPA as well as structure-property relationships known to maximise the efficiency of TPA. The subsequent chapters present explorations of the application of these dyes in biological applications; namely two-photon uncaging and two-photon photodynamic therapy. A recurring theme in my research is the discussion and evaluation of strategies for improving the compatibility of organic macromolecules with biological systems.
Uncaging is the use of photolysis to achieve a rapid increase in the local concentration of a physiologically active species via a photoremovable protecting groups. Photoremovable protecting groups are covalently attached to the physiologically active species, thus rendering it inactive. At the desired time and location, a light dose releases the molecule in its active form. There are many compounds known to uncage following photoexcitation, but there are few examples of caging groups which exhibit both strong two-photon absorption properties and highly efficient uncaging. Chapter 2 discusses the rational design of such groups through the development of a new mechanism for uncaging, in which a photoinduced electron transfer (PeT) between a two-photon-excited electron donor and an electron acceptor/release group drives the uncaging event.
Photodynamic therapy (PDT) is a treatment for neoplastic disorders such as cancer in which localised cell death is induced through photoexcitation of a sensitiser. Following light absorption, the photosensitiser enters a relatively long-lived excited state which reacts with cellular oxygen to produce its highly cytotoxic singlet form. The main challenges of the field are to achieve deep penetration of light into tissue and to reduce coincident damage to unaffected tissue by light scattering during irradiation. In 2008, the Anderson group reported the development of PDT photosensitisers with highly efficient two-photon absorption as well as high singlet oxygen quantum yields. Chapter 3 discusses strategies for improving the pharmacokinetics and defining the sub-cellular localisation of these photosensitisers.

Keywords: Photodynamic therapy
Photochemistry
Peptide synthesis
Non-linear optics
Organic synthesis
Advisor: Anderson, H
Russia's emerging margins

This thesis is concerned with the geographical impact of the post-Soviet transition on the north of Perm' oblast, Russian Federation; a forested area which is marginal in terms of agriculture and economic development, where harsh climate and marshy soils preclude profitable agriculture, and where very poor infrastructure and low levels of investment have contributed to the decline of the forestry industry, which was developed during the Soviet period outside of the market system under which such development might have been regarded as non-viable. This thesis discusses marginality and poverty against the background of the process of 'transition' in Russia, and also outlines the theory of transition itself. The historical context is also considered; the processes through which the north of Perm' oblast arrived at the position in which it found itself by 1991 are examined, and changes up to the present day are analyzed. Historically, the processes of settlement and development of forestry in the study area are central. The political situation in the Russian Federation is also brought into the argument; the struggle for power between the centre and the periphery, and the weakening of the centre in recent months all have a bearing upon the view taken of marginal areas by the Moscow administration, and the policies undertaken which affect them. The thesis describes the responses of rural inhabitants to the processes of marginalisation; through out-migration, bifurcation of households, and the ways in which they utilise their domestic and environmental resources to effect subsistence. It also describes the importance of cash sources, of social capital, and of the forestry enterprises in the villages, as survival strategies. The conditions in the study region are shown to owe much to the context of Soviet development policy, and its impact on post-Soviet Russia.
The long-term impact of the Italian colonial expenditures in the Horn of Africa

A growing body of literature analyses the relationship between colonialism and long-term development, but largely overlooks the effect of colonial public investments on transportation infrastructure, schooling and sanitary facilities. In my research, I exploit the case study of Italian colonial investments in the Horn of Africa between 1934 and 1941, to unveil the relationship between such investments and present-day inequalities in terms of level of development and living standards and to explore the mechanisms that explain the persistence of colonial investments over time.
I create three geo-referenced (a grid dataset and two individual) datasets by matching historical data on colonial investments, collected from both archival and printed primary sources, with micro-level open-source contemporary data for development and modern surveys for living standards to perform OLS and probit regression analysis. Firstly, I regress proxies for level of development, such as population density and light density at night, on dummies for being within 20km from colonial roads. Secondly, I regress measures of living standards, such as female literacy, BMI and children holding a sanitary card, on binary variables for living less than 10km away from a colonial schools and hospitals. Several robustness checks are performed to address the possible endogenous placement of colonial facilities including IV estimation, placebo treatment and nearest neighbour score matching.
The data show a strong, positive and statistically significant relationship between proximity to colonial roads and economic development, on the one hand, and proximity to schooling, sanitary facilities and living standards, on the other. This demonstrates that areas endowed with more generous investments from the colonial period perform better in terms of economic development and living standards at present. The analysis also points out that the effect persisted mainly through phenomena of path-dependency and re-location.

Keywords: Economic history
History of the Italian colonization
Development
History of Africa
Advisor: Fenske, J
Functions of conserved centriole proteins in African trypanosomes

Centriole and basal bodies are related nine-fold symmetric microtubule-based eukaryotic organelles central to the organisation of cilia/flagella and centrosomes. Mechanisms of eukaryotic centriole and basal body assembly are mainly based on studies in animal systems.
To understand which centriolar proteins are the universally important ones in the assembly across eukaryotes, a bioinformatic survey presented here investigates the distribution of centriolar and cilia-associated proteins across a diverse range of eukaryotes. This analysis showed also that the basal body function is ancestral to eukaryotes, whereas centrosomal components are specific to Holozoa (which include animals). It also suggested that the ancestor of all eukaryotes possessed a cilium/cilia not only with motility function but also with a sensory role. The most frequently conserved proteins in extant ciliated eukaryotes found in this analysis included SAS-6, SAS-4 and WDR16. To test whether these proteins are also important for basal body assembly in distantly-related species to metazoan and other model organisms where the proteins have been studied to date, the proteins were investigated in Trypanosoma brucei. I used a combination of genetic tools and microscopy techniques to demonstrate that SAS-6 but not SAS-4 is essential for basal body assembly in T. brucei. I showed that WDR16 is a stably integrated component of the transition zone and axoneme but not the basal body. Furthermore, I identified a novel SAS-6 like protein which localises to a position consistent with the basal plate and has the capacity to form into filaments.
This thesis provides new insights into the evolution of centrioles and basal bodies, and into the function of conserved centriole proteins in T. brucei, a distantly-related organism to animals.

Keywords: SAS-6
basal body
Trypanosoma brucei
centriole
SAS-4
Advisor: Gull, K
Wickstead, B
Symmetries of free and right-angled Artin groups

The objects of study in this thesis are automorphism groups of free and right-angled Artin groups. Right-angled Artin groups are defined by a presentation where the only relations are commutators of the generating elements. When there are no relations the right-angled-Artin group is a free group and if we take all possible relations we have a free abelian group.
We show that if no finite index subgroup of a group G
contains a normal subgroup that maps onto mathbbZ
, then every homomorphism from G
to the outer automorphism group of a free group has finite image. The above criterion is satisfied by SLm(mathbbZ)
for mgeq3
and, more generally, all irreducible lattices in higher-rank, semisimple Lie groups with finite centre.
Given a right-angled Artin group AGamma
we find an integer n
, which may be easily read off from the presentation of AG
, such that if mgeq3
then SLm(mathbbZ)
is a subgroup of the outer automorphism group of AGamma
if and only if mleqn
. More generally, we find criteria to prevent a group from having a homomorphism to the outer automorphism group of AGamma
with infinite image, and apply this to a large number of irreducible lattices as above.
We study the subgroup IA(AGamma)
of Aut(AGamma)
that acts trivially on the abelianisation of AGamma
. We show that IA(AGamma)
is residually torsion-free nilpotent and describe its abelianisation. This is complemented by a survey of previous results concerning the lower central series of AGamma
.
One of the commonly used generating sets of Aut(Fn)
is the set of Whitehead automorphisms. We describe a geometric method for decomposing an element of Aut(Fn)
as a product of Whitehead automorphisms via Stallings' folds. We finish with a brief discussion of the action of Out(Fn)
on Culler and Vogtmann's Outer Space. In particular we describe translation lengths of elements with regards to the `non-symmetric Lipschitz metric' on Outer Space.

Keywords: partially-commutative groups
Right-angled Artin groups
graph groups
automorphism groups of free groups
Advisor: Bridson, M
Global cloud properties on Venus from orbital infrared spectroscopy

This thesis describes the derivation of Venusian global cloud properties from infrared remote sensing data obtained by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on the European Space Agency Venus Express satellite. A computationally-efficient retrieval method is designed to exploit the dataset, which provides coverage of the entire nightside southern hemisphere of Venus. Spatially-resolved near-infrared spectra have been used to derive improved models of the vertical structure and global distribution of cloud properties in the southern hemisphere. Wavelengths within transparency windows in the 1.0 - 2.6 micron range covered by VIRTIS are sensitive on the nightside to absorption by the lower and middle sulphuric acid cloud layers, which are back-lit by thermally-emitted radiation from the hot lower atmosphere (Taylor et al. 1997).
The cloud model used to interpret the spectra builds on work by Crisp (1986), Pollack et al. (1993) and Grinspoon et al. (1993). Retrieved parameters are the acid concentration in the cloud droplets, the average size of the particles in the lower cloud and the altitude of the cloud base in the model. Values are estimated initially using wavelength pairs selected for their unique sensitivity to each parameter, and then validated using model spectra generated using the NEMESIS radiative transfer and retrieval code (Irwin et al. 2008) as developed for Venus (Tsang et al. 2008a).
The spatial variation of sulphuric acid concentration in the cloud particles is estimated ; the concentration is found to be higher in regions of optically thick cloud. The retrieved cloud base altitude varies with latitude, reaching a maximum height near -50 degreees before falling by several km towards the pole. An increase in average particle size near the pole (Wilson et al. 2008) and the finding of latitudinally-variable CO abundance at 35 - 40 km altitude (Tsang et al. 2008) are both confirmed. A decrease in tropospheric H₂O abundance at high latitudes is observed, and provides evidence for strong downwelling between +/-60 and +/-75 degrees latitude, which marks the poleward extent of the Hadley cell circulation. Long-term secular change is also observed over a period of two Earth years. The measurements presented here provide a reference dataset for microphysical and dynamical modelling of the cloud deck, and the role of the cloud as a dynamical and chemical tracer means that such observations are of considerable value for increased understanding of the Venusian atmosphere.

Keywords: VIRTIS
clouds
Venus
spectroscopy
Venus Express
Advisor: Taylor, F
Rapid reorganisation in the adult auditory system following unilateral deafening

This thesis examines functional and neurochemical reorganisation within the adult mammalian inferior colliculus (IC) and primary auditory cortex (AI) following unilateral deafening. Contralateral cochlear ablation, either on the day of recording or at least three months prior, caused an increase in the proportion of IC recording sites excited by acoustic stimulation of the ipsilateral ear in the adult ferret. In the gerbil IC, these changes occurred within minutes of contralateral cochlear ablation. Likewise, in ferret AI, contralateral cochlear ablation could produce a dramatic and rapid expansion of the cortical area that was excited by ipsilateral acoustic stimulation.
In both gerbil IC and ferret AI, significant changes in other response properties were not generally observed between multiple-unit recordings made before and after acute cochlear ablation. Areas of emergent excitation (excited post-ablation but not pre-ablation) displayed normal tuning and response properties, implying the existence of apparently normal, but unexpressed ipsilateral excitatory connections in the IC and AI of pre-ablation animals. A rapid unmasking mechanism, involving release from spontaneously-driven contralateral inhibition, is proposed. A reduction of inhibition on a longer time scale (4-24 hours) is suggested by an observed reduction in glutamic acid decarboxylase in the adult gerbil IC contralateral to the ablated ear.
Optical imaging of intrinsic signals was pioneered as a technique for examining functional organisation in ferret AI, and several protocol improvements were found for imaging normal ferret AI. However, an unforseen influence of vascular noise upon the small ipsilateral optical signal made pre- and post-ablation image comparisons difficult to interpret.
Overall, the experimental work presented here shows that the adult auditory system, like other mature sensorimotor systems, is capable of rapid functional reorganisation. The most rapid changes appear to be mediated by unmasking of previously inhibited connections.
Studying the altered reactivity of electrochemical systems in room temperature ionic liquids

The work presented in this thesis examines the electrochemical behaviour of a number of species, both surface-bound and in the solution phase, in various room-temperature ionic liquids (RTILs), in order to identify systems which show altered reactivities in room-temperature ionic liquids, compared to that in conventional, molecular, aprotic solvents. The fundamentals of electrochemistry are outlined and an introduction to room-temperature ionic liquids is given, after which the results of six original investigations are presented, as follows;
The electrochemical response of surface-bound anthraquinonyl films was investigated as a function of RTIL cation size.
The reduction of oxygen to superoxide in the [C2mim][NTf2] RTIL was studied at different carbon electrodes.
The mechanisms of electrodeposition and stripping of Zn(II) onto bulk zinc deposits, on glassy carbon electrodes, in the [C4mPyrr][NTf2] RTIL were investigated.
A novel and successful method for the fabrication of zinc microdisk electrodes was developed and the electrochemical behaviour of these electrodes was investigated.
The mechanisms for the electrochemical reductions of some bromo- and nitrobenzenes at platinum microelectrodes were determined in the [C4mPyrr][NTf2] ionic liquid, in order to identify systems which displayed changed reactivities in RTILs compared to those in molecular aprotic solvents.
The altered reactivity of 1-bromo-4-nitrobenzene in the [C4mPyrr][NTf2] ionic liquid was utilised via electrochemical reduction at zinc microelectrodes in order to form arylzinc compounds.
The work presented in this thesis shows that the oft-taken view that the reactivity of a given species in an ionic liquid will mimic that in conventional aprotic solvents is not always the case. Reactivities can be markedly different between RTILs and aprotic solvents and can also be highly dependent on the specific ionic liquid employed.

Keywords: electrosynthesis
kinetics
simulation
electrochemistry
cyclic voltammetry
mechanistics
reactivity
thermodynamics
microelectrodes
chronoamperometry
room temperature ionic liquids
Advisor: Compton, R
Generation of uncorrelated photon-pairs in optical fibres

Light, which is composed of discrete quanta, or photons, is one of the most fundamental concepts in physics. Being an elementary entity, the behaviour of photons is governed by the rules of quantum mechanics. The ability to create, manipulate and measure quantum states of light is not only useful in foundational tests of quantum theory, but also in a wide range of quantum technologies – which aim to utilize non-classical properties of quantum systems to perform tasks not possible with classical resources. Only recently has it been possible to control the properties of number states of light, which have a fixed photon-number. Two-photon states are central to testing fundamental physical theories (such as locality and reality) and the implementation of quantum information technologies. The versatility of photon-pair states is en- abled by the potential entanglement properties it can posses. Thus controlling the correlations between photons is crucial to both pure and applied physics. To produce a single photon, a photon-pair state can be used. Detection of one photon indicates its twin’s existence. Many applications, such as optical quantum computation, require pure indistinguishable single photons. Heralding single pho- tons from a photon-pair will, in general, produce single photons in a mixed quantum state due to correlations within the pair. A common approach to creating photon-pairs is through the nonlinear sponta- neous four-wave mixing interaction in optical fibres. This thesis presents a theoreti- cal and experimental implementation of a scheme to tailor the spectral correlations within the pairs. Emphasis is placed on engineering the two-photon state such that they are completely uncorrelated. Spatial entanglement is naturally avoided due to the discrete nature of the optical fibre modes. Spectral correlations are eliminated by careful choice of dispersion characteristics and conditions. The purity of the photons generated by this scheme is demonstrated by means of two-photon inter- ference from independent sources. We measure a purity of (85.9 ± 1.6)% with no spectral filtering, exhibiting the usefulness of this source for quantum technologies and applications.

Keywords: quantum optics
spontaneous four wave mixing
photon
entanglement
photon pair
biphoton
Advisor: Walmsley, I