Education drives labour market outcomes and social mobility. When educational attainment is influenced by socioeconomic factors, many students from disadvantaged backgrounds are left behind. This is undesirable as it greatly reduces the human capital that could have been present in the national economy, therefore affecting the potential of economic growth. The purpose of this thesis is to analyse the impact of a policy that has the purpose of reducing the gap in educational attainment between disadvantaged students and their peers.  The analysis takes place over a 12 year time span and across 22 local authority areas in Wales. The results highlight the importance in the measure of the attainment gap. The implementation of Pupil Premium can be correlated with a reduction in the gap that is defined by the proportional difference between disadvantaged students and their peers. The magnitude of the attainment gap has stayed fairly constant but overall attainment has risen significantly over the period under analysis.  There is room for further study into the possibility that the impact of Pupil Premium has affected some groups of students more than others.

Prefabricated baby food is under strict EU legislation by Commission Regulation (EC) 1881/2006 Setting maximum levels for certain contaminants in foodstuffs regarding the maximum allowed content of potentially harmful elements. For potentially toxic trace elements the regulated maximum content is regulated for lead, cadmium, mercury, inorganic tin, inorganic arsenic, cesium, copper and manganese. The Swedish national food agency (Livsmedelsverket) conducts chemical analyses of the regulated elements by full microwave acid digestion followed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis. In this study a simple artificial in vitro digestion method was developed using a commercially available enzyme supplement and optimized to determine the bio-accessible amount of eight potentially harmful metal trace elements that are associated with modern electronics (lithium, vanadium, cobalt, nickel, arsenic, selenium, cadmium and lead) in five prefabricated baby meals from the Swedish market by well-established manufacturers. The results were compared to the total mass content as well as the regulated limits and toxicological literature data. The samples had analyte dry mass contents that were extractable by the developed in vitro method that ranged from 0.0314 μg g-1 to 0.0691 μg g-1 for lithium, 9.42*10-5 μg g-1 to 0.0152 μg g-1 for vanadium, 6.61*10-3 μg g-1 to 30.9*10-3 μg g-1 for cobalt, 0.0599 μg g-1 to 0.194 μg g-1 for nickel, 4.54*10-4 μg g-1 to 0.0431 μg g-1 for arsenic, 8.87*10-4 μg g-1 to 9.85*10-3 μg g-1 for cadmium and 1.24*10-3 μg g-1 to 0.0232 μg g-1 for lead. Selenium was not detected in any of the samples. None of the samples were found to contain toxic levels of any of the quantified elements. Comparisons and paired t-tests of recoveries between the in vitro digestion and control procedures consisting of digestion solutions that exclude either enzymes, pH adjustment or both suggested that lithium, cobalt and cadmium were protein bound and that the digestion enzymes used had a statistically significant effected on the recovery. With further optimization and more extensive comparison to reference data the method could potentially be established as a simple and affordable alternative to more elaborate methods for screening or small scale analysis of the bio-accessible fraction of metal trace elements in food.

The objective of this work is to enhance the understanding of the delay observed in the early stages of E-coat deposition. E-coat deposition has been widely used by industries such as the automotive industry to form the primary protective coating against corrosion. Currently, models that are used to find the best conditions under which the desired coating coverage for the entire auto body can be achieved do not accurately predict the coating coverage in recessed areas. The accuracy of large-scale models can be improved by enhancing our understanding of the mechanisms responsible for the observed delay. To accomplish this, experiments are performed to define the processes that control deposition initiation and then a model is developed to describe those processes. Simulation results are compared with experimental measurements for a range of conditions to assess the validity of the results. The delay before the onset of deposition is influenced by the type of substrate and properties of the E-coat solution. The impact of the substrate type on the onset of deposition was experimentally investigated. The results of experiments indicated that surface characteristics such as adhesion of bubbles to the surface and the formation of an initial coating increase the local current density on the surface. Investigations of the morphology of the initial coating on different types of substrates indicated that deposition began at areas where the local current density was higher. Increasing the local current density due to the adhesion of bubbles to the surface resulted in a 40% reduction in the time required for the onset of deposition on galvanized steel compared to bare steel. The processes in the solution adjacent to the surface were also investigated to understand the mechanisms responsible for the onset of deposition. Convection was used as a tool to determine the impact of the accumulation of hydroxide ions on the onset of deposition. The results of rotating disk electrode (RDE) experiments showed that the observed delay before deposition was not due to the time required for accumulation of hydroxide ions at the surface. The results of additional experiments showed that the accumulation of micelles was critical to the deposit initiation. The impact of micelle accumulation on the deposit initiation was further explored by developing a mathematical model of the physical processes in the solution adjacent to the surface. The model was evaluated at different conditions and was found to agree with experimental results at different current densities and bulk micelle concentrations. The model and the experimental results from this study help to explain the observed delay in the early stages of E-coat deposition and provide a basis for improving large-scale simulation of E-coat deposition.

Philosophiae Doctor - PhD / This thesis investigates socio-spatial trajectories of class formation and processes of accumulation from below and above on redistributed farmland, the ‘New Qwaqwa Farms’ in the Eastern Free State province of South Africa, from the mid-1980s to 2016. Class formation trajectories of the studied land beneficiaries are traced across localised historical geographies and political contexts, from apartheid to the current democratic dispensation, that is, from the land beneficiaries’ recent ancestral history as labour tenants on white-owned farmland, and subsequent systematic expulsions from farmland, to their Bantustan labour reserve resuscitations as mainly nonagricultural petty commodity producers, and later targeting for land reform, as one measure of redistribution. The study adopted a mixed-methods survey, combining indepth qualitative and quantitative data, informed by critical realism and historical materialism within Marxist agrarian political economy. This methodology was retrospective, circumspective and prospective in unravelling agricultural households’ livelihood trajectories over time and space. The state’s targeting of classes of labour and fragments of the middle class as beneficiaries of land reform in the area of study has materialised into heterogeneous land reform outcomes centred on differentiated farming systems, farming scales, and farm labour requirements. Research findings suggest class differentiation of a sample of 62 cases of family farms into agricultural households engaged in social reproduction (50%), simple reproduction (26%), and accumulation (24%). The first two categories, constituting 76% of the sample, are essentially small-scale capitalist enterprises engaged in constrained and successful reproduction of capital – some of these households can be theorised as an impoverished landed property for their reliance on farm-rental income, combined with marginal farming, and precarious off-farm work for social reproduction. These are small-scale capitalist enterprises on the basis of the capital-wage relation. Their farm production rest upon small livestock herd reproduction and generalised renting out of arable and grazing land. A minority of these small-scale capitalist farms use solely family labour and can thus be defined as petty commodity producers on the basis of their embodiment of the capital-wage relation in one soul or family. The third category constitutes agricultural households on upward trajectories of capital accumulation from below and above, through expanded reproduction of mixed-farming systems, expressed in intensive farming of small but capitalised farms, as well as extensive farming expressed in livestock expansion/accumulation and renting in of additional grazing land, plus capital intensive crop expansion on non-irrigated land and renting in of additional arable land by some of the top 24% of the sample. These research findings illuminate heterogeneous land reform outcomes centred on improved access to land for widening the base of social reproduction for classes of labour, and attendant simple reproduction of small-scale capitalist farms. This heterogeneity also includes the function of land reform for accumulation of capital for the black middle class who can muster off-farm capital resources into expanded farm reproduction on their own and without accumulation from above, demonstrated by some accumulators in the area of study. Accumulation from above is taking place on some of the studied land reform farms, often through intersections with economic histories of accumulation from below, exposing the contradictions of capitalism and attendant compulsions of accumulators to accumulate capital by any means necessary. The downside of accumulation from above, however, through capture of public agricultural subsidy in the area of study, is that the collective 76% of the sample at the lower ends of social differentiation and those accumulators excluded from extraeconomic accumulation, are barred from accessing state subsidy that benefit a few politically-connected farmers. Whether class alliances across those excluded from accessing state subsidy will materialise into overt political action in demanding a share of public goods from the local ruling elite remains to be seen. These research findings contribute to a heterogeneous understanding of land reform which is sensitive to differentiated livelihood outcomes. Prospectively, this suggests much-needed government policy tailored to different classes of farmers in post land reform localities.

Antarctic mass balance is mainly controlled by surface mass balance (SMB, i.e. the net effect of precipitations at the surface of the ice sheet) and ice discharge at its margins, mostly through ice shelves. These floating ice bodies made from ice flowing from the continent to the ocean are buttressed by ice rises (elevation of the sea floor on which ice shelf re-grounds) such as the Derwael Ice Rise (DIR) in Dronning Maud Land (DML). In addition to this role important to consider in the future contribution of Antarctica to sea level rise, ice rises are also “climate dipsticks” helping to reconstruct the climate of the past centuries to millennia at high resolution. Due to their coastal location, they witness the changes happening there more rapidly than inland. Furthermore, their internal stratigraphy forms arches that allow to assess their stability, to date their own formation and therefore, in some cases, to constrain the past extension of the ice sheet at the scale of several millennia. As part of the IceCon project :Constraining ice mass changes in Antarctica, this thesis aimed to drill a 120 m ice core (named IC12 for the IceCon project, 2012) at the divide of the DIR and perform physico-chemical analyses to study its density and its internal annual layering with the aim of reconstructing SMB of the last two centuries. We also recorded a virtual image of the borehole using an optical televiewer (OPTV) to assess the ability of this instrument to reconstruct a density profile and measure vertical strain rates when the logging is repeated in the same borehole after a sufficient period of time (here, 2 years).The results show a general increase in snow accumulation rates (SMB) of 30-40% during the 20th century, particularly marked during the last 20-50 years. SMB variability is governed to a large extent by atmospheric circulation and to a lesser extent by variations in sea ice cover. The vertical velocity profile measured from repeat borehole OPTV was applied to refine SMB correction and the results fall in the error range of the corrections made using a model previously developed to study the DIR’s stability. This thesis also contributed to characterizing the spatial variability of SMB across the DIR by dating internal reflection horizons (IRHs), former surfaces of the DIR buried under subsequent snow layers and detected using radio-echo-sounding, and by measuring the density profile of IC12. SMB is found to be 2.5 times higher on the upwind slope than on the downwind slope due to the orographic effect. This pattern is regularly observed on ice rises in DML and stresses the importance of adopting a sufficient spatial resolution (5 km) in climate models.Finally, the technical developments allowing to rapidly reconstruct a density profile from the OPTV image of a borehole contributed to improving our knowledge of two features of Antarctic ice shelves, namely melt ponds, influencing surface mass balance and subglacial channels, influencing basal mass balance. Specifically, the results show that density is 5 % higher in surface trenches associated with subglacial channels, and that ice below melt ponds can reach the density of bubble-free ice due to melting and refreezing processes, with implications on ice shelf viscosity. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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Biofilms of the bovine rumen bacterium Actinobacillus succinogenes have demonstrated their exceptional capabilities as biocatalysts for high productivity, titre and yield production of succinic acid (SA). Succinic acid is set to become a significant building block chemical in the biobased economy. Although substantial progress has been made towards understanding the productive aspect of this microorganism with regard to its metabolic limits and performance on unrefined biorefinery stream substrates, more research is still required to address other challenges. One aspect is to understand how the biofilm biocatalyst is affected by bioreactor conditions, which would help in developing stable and highly active biofilms. For this reason the aim of this thesis was (i) to characterise how the accumulation of acid metabolites in continuous operation impacts A. succinogenes biofilms with respect to biofilm development, biofilm structure and cell activity within the biofilm, (ii) to show how shear conditions in the fermenter can be used to manipulate the biofilm structure and viable cell content of biofilms, leading to improved cell-based succinic acid productivities, and lastly (iii) to investigate the internal mass transfer effects on biofilm performance, further showing the role played by differences in shear and acid accumulation conditions in this respect. The first part of the study addressed the interaction between the biofilm and the accumulation of metabolites produced. The results showed that biofilms of A. succinogenes develop rapidly and with high activity when cultivated under low product accumulation (LPA) conditions (< 10 g L-1 SA). High product accumulation (HPA) conditions considerably slowed down biofilm development, and increased cell mortality. Under HPA conditions some cells exhibited severe elongation while maintaining a cross-sectional diameter like the rod/cocci-shaped cells predominantly found in LPA conditions. The elongated cells formed in HPA conditions were found to be more viable and thus more resistant than the clusters of rod-shaped or cocci-shaped cells. The global microscopic structure of the HPA biofilms also differed significantly from that of the LPA biofilms. Although both exhibited shedding after 4 days of growth, the LPA biofilms were more homogenous (less patchy), thicker and had high viability throughout the biofilm depth. In the second part of the study, two custom-designed bioreactors were used to evaluate the effect of shear on the biofilms. The first bioreactor allowed for in situ removal of small biofilm samples used for microscopic imaging. The second bioreactor allowed for complete removal of all biofilm and was used to analyse biofilm composition and productivity. Results clearly indicated that high shear biofilm cultivation in LPA conditions has beneficial morphological, viability and cell-based productivity characteristics. The smooth, low-porosity biofilms obtained under high shear and LPA conditions had an average cell viability of 79% (over a 3-day cultivation period) compared with the low shear value of 57%, also developed under LPA conditions. The EPS content of the high shear biofilm was 58% compared with 7% of the low shear equivalent. The cell-based (EPS excluded) succinic acid productivity for the high shear biofilm was 2.4 g g-1DCW h-1 compared with the 0.8 g g-1DCW h-1 for the low shear biofilm. This threefold increase in productivity obtained from the second bioreactor corresponded to the cell viability differences obtained from the first bioreactor. Clear evidence was provided for shear-induced shaping of the biofilm which resulted in improved volumetric glucose turnover attributes within the biofilm matrix. The last section of the study investigated internal mass transfer effects in biofilm fermentations of Actinobacillus succinogenes by performing batch fermentations using attached and resuspended biofilms as biocatalysts. In the latter, the biofilms were resuspended after initial development to simulate mass transfer-free fermentations. Intrinsic kinetics for succinic acid production obtained from resuspended fermentations predicted faster production rates than for the attached biofilm runs (biofilm thicknesses in the range of 120–200 µm), indicating internal mass transfer limitations. A developed biofilm reaction diffusion model gave good prediction of attached biofilm batch operation results by accounting for internal mass transfer in the biofilm. Biofilm effectiveness factors ranged from 75% to 97% for all batches at the inception of batch conditions, but increased with the progression of batch operation due to the increased succinic acid titres which inhibited the production rates. Analysis of pseudo-steady-state continuous fermentation data from the literature, as well as from the second part of the study, using the model developed, showed that active biofilm thickness and effectiveness factors were dependent on the shear conditions and succinic acid titres in the biofilm reactors. A simplified algorithm was developed to estimate the pseudo-steady-state glucose penetration and biofilm effectiveness of A. succinogenes biofilms without the requirement to solve the overall mass transfer model. The results clearly showed that internal mass transfer needs to be considered in biofilm fermentations involving A. succinogenes as high biomass concentrations may not always equate to increased productivities if mass transfer effects dominate. / Thesis (PhD)--University of Pretoria, 2020. / NRF / Chemical Engineering / PhD / Unrestricted

Thesis (M. A.(English Studies)) --University of Limpopo, 2019 / This study explores a literary comparative examination of crime between Africa and Scandinavia, with special attention to Botswana and Norway. Smith’s and Nesbo’s selected novels are used as primary texts for analysis. The novels are, therefore, set in two different areas. These writers depict crime from the African and European perspectives. Chapter One deals with a brief introduction, and the aim and objectives of the study. It also expands on the theoretical background and provides definitions of terms that are used in this paper. Chapter Two presents views from various scholars on crime. This study is based on an Afro-Western approach of literary analysis. In other words, there are thoughts by both African and Western writers which assist in determining possible and noticeable similarities and differences, on the issue of crime. Chapter Three analyses crime from an African perspective while Chapter Four discusses crime from a Western point of view. Each of these chapters reflects on crime through character portrayal and depiction within its context. Chapter Five is a comparative analysis of both novels. The chapter identifies possible similarities and differences, mainly of the depiction of crime in different settings – Africa and Scandinavia, committed by blacks and whites. However, the structural and linguistic approaches of both the novels are also reviewed, assisting in discovering the life, in comparison, of the authors. The last chapter (Chapter Six), is a conclusion of the study and future suggestions. Basically, the study argues that blacks only should not be portrayed as perpetrators, but that whites too can be culprits. Again, there should be an equal of measurement on the weight and honour of the two races. Lastly, the moral is that without considering skin colour, financial and social backgrounds, justice must be served equally. Hence, whoever is caught in any form of wrongdoing, they must be given the appropriate punishment – regardless of race, colour, religious creed, gender, financial and social background. Key Words: Crime, Afro-Western, Marxism, suspense, detective, identity, puzzle, fix, accumulation, class, characterisation and setting

Using data from the 2006 Health and Retirement Study (HRS), this study examines what types of assets and levels of savings are held by Black near-retirees, while comparing how types of assets and levels of savings of Black near-retirees differ from those of White near-retirees. Through the use of multivariate analyses, this study further investigates the effects of being Black on the levels of savings, the likelihood of holding IRAs, and the likelihood of being financially prepared for retirement. The study sample includes 4,077 individuals between the ages of 51 and 64, and the subsamples consist of 680 Black and 3,397 White near-retirees. Descriptive findings suggest that Black near-retirees hold lower levels of financial assets (i.e., checking accounts, CDs, stocks, bonds, and other savings) and non-financial assets (i.e., business, real estate, vehicles, and residential home) compared to their White counterparts. The descriptive results further indicate that overall, the level of net worth, holding IRAs, and the investment assets-to-net worth ratio for Black near-retirees are lower than that for White near-retirees. The results from both the ordinary least squares (OLS) regression and the logistic regression analyses indicate that with all else being equal, being Black is a significant factor in predicting the levels of savings, the likelihood of holding retirement accounts, and the likelihood of being financially prepared for retirement among near-retirees aged 51-64. This study also explores how human capital factors and socioeconomic factors are associated with the levels of savings among Black Americans aged 51-64. The OLS results suggest that Blacks with higher education and longer job tenure, and who are married hold higher levels of net worth than other Blacks. The logit results indicate that Black near-retirees with a college education are more likely to hold IRAs; those with longer job tenure are more likely to hold IRAs; and those in the top income quartile are more likely to hold IRAs. The findings of the logit results also indicate that Black near-retirees with some college education, longer job tenure, and those in the higher income groups are more likely to be financially prepared for retirement.