VictorJuiz/thesis huggingface dataset:
The characterisation of calcrete based on its environmental settings within selected regions of the Kalahari, Southern Africa

Chemical sediments in a variety of geomorphic environments (pedogenic, fluvial, palustrine, lacustrine and pan) were investigated from seven regions (SW Kalahari, Kgalagadi, Kalkweissrand, Etosha, Linyanti, Okavango and Ngami) in the Kalahari of southern Africa. These primary and multi-phase sediments were characterised by a range of pure and intergrade silcrete, calcrete and dolocrete fabrics which contained an array of structures indicative of the crystalline and biogenic processes responsible for their precipitation, epigenesis and paragenesis. Petrography, mineralogy and isotope geochemistry provided significant insight regarding the environmental and geochemical conditions at the time of precipitation. Petrography indicated that the majority of chemical sediments were undergoing epigenetic modification as a consequence of the desiccation induced transition from phreatic to vadose diagenetic and geochemical conditions. The role of rapidly infiltrating meteoric water, associated with unstable wetting fronts, is believed to be instrumental in vadose diagenesis and the precipitation of crystalline/alpha fabric carbonate. Salinisation within the capillary fringe and deeper vadose zone is believed to be responsible for the sequence dolomitisation of crystalline calcite within mature sequences. Highly saline pan conditions instigate the precipitation of authigenic dolomite, calcite and K-feldspar within the surface sediments and authigenic silica at depth. Phreatic water beneath the islands, floodplains and fluvial systems of the Okavango, which undergoes evapotranspirational and transmission salinisation and ultimately terminal desiccation, are similarly precipitating silcrete. Pedogenic processes principally associated with C4 vegetation are responsible for the gratification of carbonate mud within desiccating lacustrine, palustrine and pan sediments. Within the thin sandy Kalahari soils, pedogenesis is limited, but biogenic/beta fabric precipitation linked to mycorrihizae and tree/shrub savanna vegetation is instrumental in the formation of hardpans and the modification of upper calcrete horizons. The dominance of a distinct assemblage (smectite/kaolinite or sepiolite/palygorskite) of authigenic clay minerals present within all the environments provides evidence of semi-arid precipitation within Mg and Ca enriched saline/rapidly evaporating water or brackish/reduced permeability environments.

Advisor: Goudie, A
The construction of the South: developing countries, coalition formation and  the UN climate change negotiations, 1988-2012

The North-South divide is one of the central political characteristics of the UN climate change negotiations. But while the Group of 77 coalition has been the main negotiating group for the South, developing countries have often faced challenges to their unity, magnified by the recent establishment of smaller negotiating groups. How has 'the South' hung together? This thesis investigates how developing countries have formed negotiating groups over the two decades of the UN climate negotiating process. It explains the origins of the different negotiating groups that have formed over this time, as well as the timing of their emergence and the scope of their membership. In particular, while scholarly attention has focused on the G77, Alliance of Small Island States (AOSIS) and most recently the Brazil-South Africa- India-China (BASIC) coalition, this thesis corrects the relative neglect in understanding the many other negotiating groups that have formed.
While conventional explanations highlights the shared material interests that underpin group formation, this thesis advances a constructivist argument that emphasises instead the importance of collective identities in shaping norms of 'appropriate association' – the social bases of whose one's friends and allies are. It highlights the regional basis for many of these negotiating groups that cut across shared material circumstances, and draws upon historical institutionalist insights on critical junctures and path dependence to place this larger pattern of Southern coalition formation in the appropriate historical and institutional context of the UN system. It demonstrates the continuing persistence of countries identifying as the 'South', where despite changing material circumstances and disagreements among developing countries, the salience of the G77 as the constitutive institution of this identity remains. Above all, in investigating the processes of coalition formation among developing countries in the climate context, this thesis deepens scholarly understanding about the contemporary meaning of the 'South'.

Keywords: United Nations
climate change
developing countries
Advisor: Fawcett, L
Link-directionalities in carrier sense wireless networks

In this thesis, research is described which leads to the proposal of a link-directionality-based dual channel MAC (Medium Access Control) protocol (DCP) for carrier sense wireless ad hoc networks. It attempts to double the capacities of such networks using an industrial standard (the single-channel IEEE 802.11 protocol) as a benchmark. Simulations show that the proposed scheme can increase the capacities to more than 1.7 times of the single-channel IEEE 802.11 protocol in large-scale random network topologies. The algorithm, however, requires extra radio spectrum resource which could be costly.
In addition to DCP, a signal-to-interference ratio comparison algorithm (SCA) is proposed to further release the protocol constraints imposed by the virtual carrier-sensing mechanism. Interestingly, while the capacity of the pure DCP decreases when link lengths are short, the capacity of the pure SCA increases when link lengths are short. The two algorithms compensate for the downside of each other to bring about a more uniform capacity improvement. Simulations show that the integrated scheme can further increase the network throughputs to more than 2.13 times in random topologies.
This thesis also clarifies inter-link interference in wireless ad-hoc networks by using link-directional interference graphs (l-graph). By colouring the l-graphs, independent data streams obtained by Multi-Carrier Code Division Multiple Access (MC-CDMA) are assigned for transmitting up-link and down-link traffic separately in order to eliminate the hidden-node and exposed-node problems in wireless local area networks (WLAN).
Finally, a generic approach for capacity analysis is proposed to show that the concept of link-directionality can also be adopted with other network models, protocols and parameter settings. However, in certain scenarios where links are densely packed together, the advantage of using link-directionality could be diminished. Therefore, the proposed generic approach for capacity analysis allows one to determine whether channel allocations according to link-directionalities should be applied to a given network.

Keywords: MAC protocol
wireless LAN
Link-directionalities
capacity
wireless ad-hoc networks
carrier sensing
multi-channel
Advisor: Edwards, D
Polymers for electro-optic applications

Polymer based photovoltaic cells are being intensively investigated. In such cells three key processes need to occur; namely light absorption, charge separation of the exciton, and transport of the separated charges to the electrodes. Light absorption is reliant on the optical density of the polymer. In general charge separation is achieved by blending an electron acceptor with the polymer film. However, blending materials gives rise to potentially unreliable manufacturing and lifetime issues. This thesis describes the preparation of poly(l,4-phenylenevinylene) derivatives containing dipoles in which the process of charge separation can be achieved intramolecularly. The dipole was created with the use of electron donating alkoxy groups attached to the polymer backbone, and electron withdrawing nitro group attached to the fluorenyl side chains. These groups are believed to facilitate the dissociation of the photogenerated exciton, and potentially stabilise the holes and electrons that are formed when the exciton is separated. The fluorenyl side chains were attached to the polymer backbone via biphenyl or vinyl linkages. The polymers were primarily formed using the Gilch method and the conjugated polymers were obtained either via a soluble precursor route or directly from the monomer. The photophysical properties were studied for polymers with the fluorenyl side-chains as they were found to be more easily formed and stable. For poly[2-(7-nitro-9,9-dipropylfluorenyl)-5-(2'- ethylhexyloxy)-l,4-phenylenevinylene] it was found that the photoluminescence quantum yield dropped by a factor of eight relative to the polymer without the nitro group. It was further elucidated that this was due to the exciton being separated. Solar cells containing the polymers from this study showed modest performance.

Advisor: Burn, P
Multisensory integration of olfaction

The primary aim of this thesis was to investigate, using functional magnetic resonance imaging (fMRI), the neurophysiological basis of multisensory integration involving smell and vision. To achieve this goal, several technical challenges had to be addressed: the attainment of sufficiently high quality fMRI images in olfactory brain regions within the orbitofrontal cortex (OFC), the construction of a stimulus delivery system adequate for rapid and controlled odour delivery in the MRI environment, and optimal strategies for delivering and perceiving liquid flavour stimuli in the scanner.
In two initial fMRI experiments, strategies including sensitivity encoding and passive shimming to improve OFC image quality were explored. The results demonstrated that both methods can improve signal detection in OFC, a brain area particularly sensitive to susceptibility artefacts. In a further fMRI study, the effectiveness of two methods of delivering odorants dissolved in liquids was compared. In this study, the same set of participants was required to either swallow the liquid immediately after delivery or hold it in their mouths for a brief period of time. The results indicated that while both methods allowed detection of activity in primary olfactory and gustatory cortices, activation of the OFC was not observed when participants swallowed the liquids immediately. This was presumed to be due to the increased head motion associated with swallowing.
Finally, the mechanisms underlying visual-olfactory integration were investigated using a combination of behavioural and imaging methods. An initial behavioural study revealed strong colour-odour associations for certain smells associated with fruits (e.g. lemon - yellow). In a subsequent fMRI study, volunteers were presented with a selection of the most colour-associated odours from the prior behavioural study either in isolation or in the presence of congruent and incongruent colours. Analysis of the fMRI data revealed that a highly left lateralised network of brain areas comprising of the OFC and insular showed increasingly stronger responses to odour-colour combinations of higher congruency. In a follow-up fMRI study, this same network was also found to be responsible for integrating odours, not only with colours, but also with their corresponding visual images (objects). In sum, the series of fMRI studies undertaken in this thesis argue for a fundamental role of the OFC in the integration of olfactory-visual inputs in the human brain.

Advisor: Calvert, G
Matthews, P
Gemma A. Calvert and Paul M. Matthews
Accounting for sustainability in Bengal: examining arsenic mitigation technologies using Process Analysis Method

This thesis shows how the Process Analysis Method (PAM) can be applied to assess technologies used to mitigate arsenic from drinking water in rural India, using a set of sustainability indicators. Stakeholder perspectives, gathered from a fieldwork survey of 933 households in West Bengal in 2012, played a significant role in this assessment. This research found that the ‘Most Important’ issues as specified by the technology users are cost, trust, distance from their home to the clean water source (an indicator of convenience), and understanding the health effects of arsenic. It was also found that none of the ten technologies evaluated are economically viable, as many do not charge user-fees, which creates reliance upon donations to meet recurring costs. Utilisation of a technology is strongly related to sociocultural capital, but in many cases, features that contribute to sociocultural value, like regular testing of the treated water, are not included in the financial budget. It is suggested that increased awareness might change attitudes to arsenic-rich waste and its disposal protocols. This waste is often currently discarded in an uncontrolled manner in the local environment, giving rise to the possibility of point-source recontamination. All technologies proved to have difficulties in dealing with waste, except the Tipot and Dug wells which produce no waste. Of the methods considered, the BESU technology scored highest, but still only with 47-62% of the maximum scores achievable within each domain. This explains the widespread failure of mitigation projects across the region. The indicators and metrics show where improvements can be made. A model scheme based on these findings is outlined which could be applied with the objective of increasing utilisation and improving sustainability. It can be concluded that a product stewardship approach should be taken in regard to design, implementation and operation of the technologies, including the creation of a regulated toxic waste collection and disposal industry.

Keywords: Water
Groundwater
Process Analysis Method
Mitigation
India
User-Centered
Design
Metrics
Sustainability
Filters
arsenic
West Bengal
Advisor: Darton, R
Madhyamaka and Pyrrhonism: doctrinal, linguistic and historical parallels and interactions between Madhyamaka Buddhism &amp; Hellenic Pyrrhonism

There have been recent explosions of interest in two fields: Madhyamaka-Pyrrhonism parallels and Pyrrhonism itself, which seems to have been misunderstood and therefore neglected by the West for the same reasons and in the same ways that Madhyamaka traditionally has often been by the West and the East. Among these recent studies are several demonstrating that grounding in Madhyamaka, for example, reveals and illuminates the import and insights of Pyrrhonean arguments. Furthermore it has been suggested that of all European schools of philosophy Pyrrhonism is the one closest to Buddhism, and especially to Madhyamaka. Indeed Pyrrho is recorded to have studied with philosophers in Taxila, one of the first places where Madhyamaka later flourished, and the place where the founder of Madhyamaka, Nāgārjuna, may have received hitherto concealed texts which became the foundation for his school.
In this dissertation I explore just how similar these two philosophical projects were. I systematically treat all the arguments in the Pyrrhonist redactor Sextus Empiricus’ Outlines of Pyrrhonism and Against Dogmatists and compare them to the most similar arguments available in the Madhyamaka treatises and related texts. On this basis, I ask whether the Pyrrhonists and the Buddhists would satisfy each other’s self-identifying criteria, or what characteristics would disqualify either or both in the other’s eyes. I also ask what questions arise from the linguistic and historical evidence for interactions between the Pyrrhonist school and the Madhyamaka school, and how sure we can be of the answers. Did Pyrrho learn Buddhism in Taxila? Was Nāgārjuna a Pyrrhonist? Finally I bring the insights of the living commentarial tradition of Madhyamaka to bear on current scholarly controversies in the field of Sextan Pyrrhonism, and apply the subtleties of interpretation of the latter which have developed in recent scholarship to Madhyamaka and its various difficulties of interpretation, to scrutinize each school under the illumination of the other. With this hopefully illuminated view, I address for example whether Sextus was consistent, whether living Pyrrhonism implies apraxia, whether Pyrrhonism is philosophy at all, and whether Madhyamaka is actually nihilism.

Keywords: Sextus Empiricus
Scepticism
Nagarjuna
Pyrrhonism
Madhyamaka
Buddhism
Advisor: Westerhoff, J
Mathematical modelling of human sperm motility

The propulsion mechanics driving the movement of living cells constitutes one of the most incredible engineering works of nature. Active cell motility via the controlled movement of a flagellum beating is among the phylogentically oldest forms of motility, and has been retained in higher level organisms for spermatozoa transport. Despite this ubiquity and importance, the details of how each structural component within the flagellum is orchestrated to generate bending waves, or even the elastic material response from the sperm flagellum, is far from fully understood.
By using microbiomechanical modelling and simulation, we develop bio-inspired mathematical models to allow the exploration of sperm motility and the material response of the sperm flagellum. We successfully construct a simple biomathematical model for the human sperm movement by taking into account the sperm cell and its interaction with surrounding fluid, through resistive-force theory, in addition to the geometrically non-linear response of the flagellum elastic structure. When the surrounding fluid is viscous enough, the model predicts that the sperm flagellum may buckle, leading to profound changes in both the waveforms and the swimming cell trajectories. Furthermore, we show that the tapering of the ultrastructural components found in mammalian spermatozoa is essential for sperm migration in high viscosity medium. By reinforcing the flagellum in regions where high tension is expected this flagellar accessory complex is able to prevent tension-driven elastic instabilities that compromise the spermatozoa progressive motility.
We equally construct a mathematical model to describe the structural effect of passive link proteins found in flagellar axonemes, providing, for the first time, an explicit mathematical demonstration of the counterbend phenomenon as a generic property of the axoneme, or any cross-linked filament bundle. Furthermore, we analyse the differences between the elastic cross-link shear and pure material shear resistance. We show that pure material shearing effects from Cosserat rod theory or, equivalently, Timoshenko beam theory or are fundamentally different from elastic cross-link induced shear found in filament bundles, such as the axoneme. Finally, we demonstrate that mechanics and modelling can be utilised to evaluate bulk material properties, such as bending stiffness, shear modulus and interfilament sliding resistance from flagellar axonemes its constituent elements, such as microtubules.

Keywords: microbiological
Biofluid dynamics
spermatozoa dynamics
Advisor: Gaffney, E
Philip, M
The differentiation of osteogenic cells from bone marrow

According to a current hypothesis there is a putative stromal stem cell in bone marrow, capable of giving rise to adipogenic, osteogenic, fibroblastic and reticular cell lines. An aim of this thesis was to obtain information about the hierarchy and potential for differentiation of these marrow stromal cell lines in young adult rabbits. Particular objectives were to determine the conditions required for expression of the adipocytic phenotype in vitro/ to obtain cloned populations of adipocytic cells and to compare their potential for differentiation with that of populations derived from marrow fibroblastic colonies using an in vivo diffusion chamber (DC) assay.
Adipocytic colonies differentiated and grew to a limited size in medium supplemented with rabbit plasma, but attempts to isolate and expand them in this medium failed. On changing the serum supplement to FCS, adipocytic cells acquired a less differentiated morphology. There was a large increase in colony growth and cells were produced in sufficient numbers for the DC assay. 31 fibroblastic and 21 adipocytic colonies were isolated and expanded. Of these, 11 fibroblastic and 8 adipocytic colonies provided enough cells for implantation in DC's. 4 of the 11 fibroblastic and 3 out of the 8 adipocytic colonies formed bone in the chambers. It was concluded that cells which have differentiated in an adipocytic direction are able to revert to a more proliferative stage and subsequently to differentiate along the osteogenic pathway. Adipocytic and fibroblastic cells cultured in vitro from marrow have, with osteogenic cells, a common precursor in adult marrow.
Several phenotype specific differentiation markers have been identified for extra-medullary, but not marrow adipocytes. PAL422(AP2), a P2-like myelin protein is a specific marker expressed during differentiation by a number of extramedullary adipocytic cell lines. A further objective was to determine if PAL422(AP2) is expressed in marrow adipocytic cultures, and to asses its value as a marker of adipocytic differentiation in the marrow stromal system. Using western and northern blot analysis, expression of PAL422(AP2) was demonstrated in rat marrow cell cultures then localized to pre-adipocytes and young adipocytes by immunohistochemistry. Thus, PAL422(AP2) is of value as a differentiation marker of marrow adipocytes.

Advisor: Owen, M
Local knowledge of agriculture / environmental symbioses

In rural districts of Sub-Saharan Africa, livelihoods typically centre around peasant agriculture and herding. While historically effective, changing resource constraints associated with rapid population growth and resource degradation have put these livelihoods under strain. Dramatic shifts over recent years in agricultural policy and the prices of agricultural inputs and outputs have not helped. Together, such changes arguably amount to a set of destabilising influences and a relative paucity of advantageous opportunities. The question is whether local people successfully adapt their land-use strategies to these changing circumstances.
'Sustainable agriculture' technologies such as agroforestry practices represent an obvious means of adaptation to change in low-potential areas, which largely lack access to purchased agricultural inputs. Yet despite the promise these technologies have shown in farm trials, their adoption by farmers has generally been hesitant and limited. This has been widely interpreted as evidence that these technologies do not respond effectively to the needs of target beneficiaries.
Based on a household survey from Shinyanga District, Tanzania, the study revisits the issues of adaptation to changing circumstances and technology adoption. It highlights the possibility that some households adapt to change more effectively than others, with some adopting advantageous available technologies while others do not. Its focus is on the differing knowledge and perceptions informing decisions vis-à-vis tree management, with a view to identifying distinct knowledge types within the wider body of local knowledge.
The study posits then tests a theoretical model problematising local knowledge. It finds that integrating local knowledge variables into regressions of tree management practice greatly increases their explanatory power, suggesting that these variables do not simply reflect incentives, as suggested by contemporary theory. The implication is that problematic local knowledge may critically constrain rural livelihoods in areas facing unprecedented challenges and opportunities. Finally, diverse associations with observed knowledge patterns are considered, suggesting promising ways to build on this work.

Advisor: Dr Judith U. Heyer, D