Ill at ease in our translated world ecocriticism, language, and the natural environment in the fiction of Michael Ondaatje, Amitav Ghosh, David Malouf and Wilma Stockenström
- Authors: Johnson, Eleanore
- Date: 2011
- Subjects: Ondaatje, Michael, 1943- The English patient Ghosh, Amitav. The hungry tide Malouf, David, 1934- An imaginary life Stockenström, Wilma. The expedition to the Baobab tree Ecocriticism Human ecology in literature Nature in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2234 , http://hdl.handle.net/10962/d1002277
- Description: This thesis explores the thematic desire to establish an ecological human bond with nature in four contemporary novels: The English Patient by Michael Ondaatje, The Hungry Tide by Amitav Ghosh, An Imaginary Life by David Malouf, and The Expedition to The Baobab Tree by Wilma Stockenström. These authors share a concern with the influence that language has on human perception, and one of the most significant ways they attempt to connect with the natural world is through somehow escaping, or transcending, what they perceive to be the divisive tendencies of language. They all suggest that human perception is not steered entirely by a disembodied mind, which constructs reality through linguistic and cultural lenses, but is equally influenced by physical circumstances and embodied experiences. They explore the potential of corporeal reciprocity and empathy as that which enables understanding across cultural barriers, and a sense of ecologically intertwined kinship with nature. They all struggle to reconcile their awareness of the potential danger of relating to nature exclusively through language, with a desire to speak for the natural world in literature. I have examined whether they succeed in doing so, or whether they contradict their thematic suspicion of language with their literary medium. I have prioritised a close ecocritical reading of the novels and loosely situated the authors’ approach to nature and language within the broad theoretical frameworks of radical ecology, structuralism and poststructuralism. I suggest that these novels are best analysed in the context of an ecocritical mediation between poststructuralist conceptions of nature as inaccessible cultural construct, and the naïve conception of unmediated, pre-reflective interaction with the natural world. I draw especially on the phenomenological theories of Maurice Merleau-Ponty, whose insistence that perception is always both embodied and culturally mediated truly renders culture and nature irreducible, intertwined categories. By challenging historical dualisms like mind/body and culture/nature, the selected novels suggest a more fluid and discursive understanding of the perceived conflict between language and nature, whilst problematizing the perception of language as merely a cultural artefact. Moreover, they are examples of the kind of literature that has the potential to positively influence our human conception of nature, and adapt us better to our ecological context on a planet struggling for survival.
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Improved tree species discrimination at leaf level with hyperspectral data combining binary classifiers
- Authors: Dastile, Xolani Collen
- Date: 2011
- Subjects: Mathematical statistics , Analysis of variance , Nearest neighbor analysis (Statistics) , Trees--Classification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5567 , http://hdl.handle.net/10962/d1002807 , Mathematical statistics , Analysis of variance , Nearest neighbor analysis (Statistics) , Trees--Classification
- Description: The purpose of the present thesis is to show that hyperspectral data can be used for discrimination between different tree species. The data set used in this study contains the hyperspectral measurements of leaves of seven savannah tree species. The data is high-dimensional and shows large within-class variability combined with small between-class variability which makes discrimination between the classes challenging. We employ two classification methods: G-nearest neighbour and feed-forward neural networks. For both methods, direct 7-class prediction results in high misclassification rates. However, binary classification works better. We constructed binary classifiers for all possible binary classification problems and combine them with Error Correcting Output Codes. We show especially that the use of 1-nearest neighbour binary classifiers results in no improvement compared to a direct 1-nearest neighbour 7-class predictor. In contrast to this negative result, the use of neural networks binary classifiers improves accuracy by 10% compared to a direct neural networks 7-class predictor, and error rates become acceptable. This can be further improved by choosing only suitable binary classifiers for combination.
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Inflation threshold and nonlinearity: implications for inflation targeting in South Africa
- Authors: Morar, Derwina
- Date: 2011
- Subjects: Inflation targeting -- South Africa Interest rates -- Effect of inflation on -- South Africa Monetary policy -- South Africa Economic development -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:984 , http://hdl.handle.net/10962/d1002718
- Description: Following many other central banks around the world, the South African Reserve Bank has adopted inflation targeting as its monetary policy framework. The aim of this is to achieve low levels of inflation in order to attain price stability thereby promoting growth. In South Africa, the chosen band to target is 3%–6%. This has been criticised by many trade unions who are calling for the abandonment of inflation targeting. Despite targeting 3%–6%, it is not known whether this is the optimal inflation range for South Africa. Therefore, the aim of this study is to determine the inflation threshold level for South Africa using quarterly data for the period 1983 to 2010. The first section determines whether or not there is a long-run relationship between inflation and growth using the Johansen cointegration method. Exogeneity tests determine the causality between these variables. Vector error correction models are estimated if cointegration is found. The second part determines the threshold level of inflation using the method of conditional least squares. The inflation level that maximises the R-squared value and minimises the residual sum of squares gives an indication of the threshold level. The third part of the study determines whether or not inflation volatility has a significant impact on growth. The first part established that there is long-run comovement between inflation and growth.The causality is bidirectional with both variables being endogenous.Findings regarding the threshold level show that the current inflation targeting band of 3%–6% may be extended up to 9.5%. In addition, the range of inflation from 5.5% to 6.5% promotes economic growth in South Africa. Finally, the evidence suggests that inflation volatility does not have a significant impact on economic growth and the focus of policy should be directed towards the level of inflation as has been the case.
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Initial investigations into dynamics of mesozooplankton community structure in Algoa Bay, South Africa
- Authors: Dali, Luzuko O'Brian
- Date: 2011
- Subjects: Zooplankton -- Research -- Indian Ocean -- South Africa , Phytoplankton -- Research -- Indian Ocean -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5715 , http://hdl.handle.net/10962/d1005401 , Zooplankton -- Research -- Indian Ocean -- South Africa , Phytoplankton -- Research -- Indian Ocean -- South Africa
- Description: As part of a long-term monitoring programme initiated by the South African Environmental Observation Network (SAEON) Elwandle Node, the spatio-temporal dynamics of mesozooplankton (200–2000 μm) community structure in Algoa Bay, on the Eastern Cape coastline of southern Africa, was investigated in summer and winter of 2008. Physical-chemical and biological variables were measured at selected sites in the eastern and western sectors of the Bay. During summer, nutrient rich waters upwelling into the eastern sector of the Bay contributed to significant spatial variation in selected physical-chemical variables. During winter, virtually no significant spatial patterns in the physical-chemical variables were observed (P>0.05 in all cases). For the majority of physical-chemical variables, no significant seasonal patterns in values were detected (P>0.05 in all cases). Notable exceptions were water column stability and water temperatures which were highest during summer, and seston, turbidity and ammonium concentrations which attained the highest values in winter. The striking seasonal pattern observed in the water column stability, coupled with the upwelling event, coincided with a strong seasonal pattern in the total surface and integrated chlorophyll-a concentrations within the Bay. During summer, the total surface phytoplankton biomass ranged from 1.87–3.11 μg.L⁻¹ and the integrated biomass values between 44.6 and 89.1 mg chl-a m⁻². In winter, surface chl-a concentrations ranged from 0.49 to 0.55 μg.L⁻¹ and integrated biomass from 13.5 to 13.8 mg chl-a m⁻². During both seasons, the large microphytoplankton (>20 μm) fraction contributed the most (>80%) to the total phytoplankton biomass suggesting that phytoplankton growth is not nutrient limited within the Bay. The total mesozooplankton abundance and biomass values during summer varied between 10088.92 and 28283.21 ind.m⁻³ and between 76.59 and 161.94 mg.m⁻³, respectively. During winter, total abundance and biomass of mesozooplankton within the Bay were significantly lower, ranging from 2392.49 to 11145.29 ind.m⁻³, and from 34.49 to 42.49 mg.m⁻³, respectively (P<0.05). During both seasons, cosmopolitan copepod species 200–500μm in size dominated the total mesozooplankton counts, numerically and in biomass. Hierarchical cluster analyses identified distinct zooplankton groupings within the Bay during both the summer (three groupings) and winter (four groupings) surveys. The different groupings identified during the two seasons were not associated with any specific geographic region or hydrological feature. Nonetheless, a distinct seasonal pattern in the mesozooplankton community was evident, largely reflecting the increased abundance of mesozooplankton during the summer survey. Canonical Correspondence Analyses (CCA) indicated that the zooplankton community structure within Algoa Bay reflected a complex interaction between physical-chemical (e.g. temperature, water column stability, turbidity, and nitrate, dissolved oxygen and nitrite concentrations) and biological factors (e.g. microphytoplankton and picophytoplankton concentrations). These data provide baseline information towards long-term monitoring programs that will be conducted in Algoa Bay, as part of the South African Environmental Observation Network (SAEON), in the near future.
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Intellectualisation of African languages with particular reference to isiXhosa
- Authors: Maseko, Pamela
- Date: 2011
- Subjects: Xhosa language -- Study and teaching -- South Africa , Language and education -- South Africa , African languages
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/58035 , vital:27035
- Description: The research explores the relationship between language and education, and motivates for the intellectualisation of African languages, isiXhosa in particular, and for their use in education. The main rationale behind this is that access to, and success in education can largely be realised if that education is mediated in one’s first language. The thesis discusses works of prominent scholars who have written on the subject - relating cognitive abilities and achievement in education to language in which that education is offered. The lack of terminology in new domains in African languages as barrier to mother tongue education is laid bare by looking specifically at the history of intellectualisation of isiXhosa, from the missionaries in the 1820s up to the new endeavours as recently as 2008. Terminologies that were developed during the Bantu Education era, where development of isiXhosa and other indigenous African languages was accelerated in order to respond to the demands of moedertaal-onderwys (mother tongue education) are surveyed, and the process of their development analysed. Three main terminology lists developed during this period are analysed against terminology development principles, approaches and methods that are seen as a measure to ensure quality terminology development. The efforts of the development of isiXhosa during the post-apartheid South Africa, especially the government-driven initiatives, are also critiqued even though these are not as effective and as extensive, especially in education. The result of this analysis is that African languages and isiXhosa in particular, can be used in scientific disciplines and at the highest levels of education. Its grammar is advanced, and its lexicon is extensive such that new concepts that need to be named can be named, using appropriate term creation strategies. There are also technological tools such as WordSmith tools that can be used that can advance its development, ensuring that the concept represented in the newly-created term is precise, concise and appropriate in terms of its discipline. Therefore it is argued that, in the interim, terminologies should be developed, in various subjects, to support learning, which at this stage is mediated in English, for those students who have other languages as mother tongue. Those terminologies that have been developed in the various historical periods should be collated, revised and brought into the classrooms. The thesis argues that real intellectualisation of isiXhosa and other African languages rests on the use of these languages in classrooms and lecture halls, and in the value that all role players place on these languages.
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Intimate masculinities in the work of Paul Emmanuel
- Authors: Bronner, Irene Enslé
- Date: 2011
- Subjects: Emmanuel, Paul, 1969- Masculinity in art Identity (Psychology) in art Gender identity in art Art, South African -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2397 , http://hdl.handle.net/10962/d1002193
- Description: Paul Emmanuel is a South African artist who produces incised drawings, outdoor installations and prints (particularly intaglio etchings and manière noire lithographs). These focus on the representation of male bodies and experience. Having begun his career as a collaborative printmaker, since 2002, his work has become more ambitious as well as critically acclaimed. In 2010, his most recent body of work, Transitions, was exhibited at the Smithsonian Museum of African Art in Washington D.C. I propose that Emmanuel represents the male body as a presence that either is not easily seen or that actively disappears or erases itself. Its subjectivity, and the viewer’s engagement with it, may be characterised as one of intimacy, exposure, loss and vulnerability. Emmanuel’s work may be said to question conventions and ideals of masculinity while, at the same time, refusing any prescriptive interpretation. To develop this proposition, I examine specifically Emmanuel’s incising drawing technique that ‘holds open’ transitions in male lives. In these liminal moments, Emmanuel represents men as ‘seen’ to change state or status, thereby exposing the ongoing process of building masculine identities. Equally elucidatory is Emmanuel’s imprinting of his own body, which, in his use of “traces” that reveal the vacillation between presence and absence, makes contingently ‘visible’ this gendering process, and has particular implications for the expression of subjectivity in a contemporary South African context.
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Investigating at the grassroots: exploring the origins, purposes journalistic practices and outcomes in two award-winning Daily Dispatch editorial projects
- Authors: Lunga, Carolyne Mande
- Date: 2011
- Subjects: Investigative reporting -- South Africa -- Eastern Cape Citizen journalism -- South Africa -- Eastern Cape Reporters and reporting -- South Africa -- Eastern Cape Journalism -- Social aspects -- South Africa -- Eastern Cape Journalism -- Political aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3452 , http://hdl.handle.net/10962/d1002906
- Description: This thesis explores the origins, purposes, journalistic practices and outcomes of two award-winning projects namely Broken Homes and Slumlords done by Daily Dispatch's Gcina Ntsaluba in 2009. The projects were described by the paper as investigative journalism but interestingly the original idea came from grassroots driven strategies and they were done by adopting alternative news gathering strategies and immersion in the ordinary people, inspired by public journalism. This thesis follows Christians et al's (2009) normative theoretical framework of press roles summarised as the monitorial, facilitative, collaborative and radical roles. It provides normative prescriptions of public and investigative journalism, development and radical journalism. It then draws on sociological theoretical critiques in order to provide an analytical overview of the complex matrix of political, economic and media contexts which influenced the origins, purposes, journalistic practices and outcomes of the two projects. Drawing on a critical realist case study design, the thesis goes on to provide a narrative account of the two projects based on the in-depth interviews exploring the editorial staffs ideas on the origins, purposes, journalistic practices and outcomes of the projects and a qualitative content/thematic analysis of the journalistic texts related to the projects. This primary data is then critically evaluated against normative theories of press performance, especially Nip's (2008) key practices and Haas's (2007) 'public philosophy' of public journalism. It is also evaluated against a normative framework of what constitutes "good investigative journalism" based on Ettema and Glasser (1998), Waisbord (2000) among others. Protess et al 1991's classic mobilisation model is used to interrogate the projects' outcomes. The thesis established that there was a close connection of the monitorial (investigative journalism), facilitative (public journalism) and radical (tabloid journalism) roles at the paper which shows that the roles are not mutually exclusive. The two projects however fell short of the collaborative role (development journalism) which can, partly, be attributed to the adversarial nature of the relationship between the state and the media. The Daily Dispatch also failed to activate a platform for deliberation and public problem solving. There might thus be more scope in adopting a 'facilitative monitorial role' which would not only expose those who violate other people's human rights, corrupt people and institutions that are not performing well. Instead it will also activate civic life and facilitate 'collaboration' between government and the publics in problem solving.
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Investigating the popularity of the main news bulletin on Muvi TV, a Zambian television station: a reception study of Lusaka viewers
- Authors: Mbatha, Loisa
- Date: 2011
- Subjects: Television broadcasting of news -- Research -- Zambia Broadcast journalism -- Research -- Zambia Television programs -- Research -- Zambia
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3463 , http://hdl.handle.net/10962/d1002918
- Description: The "tabloid TV" genre, like tabloid newspapers has been chastised for depoliticising the public by causing cynicism, and lowering the standards of rational public discourse. Such criticisms are not always based on a close interrogation of the reasons for the popularity of such a genre amongst its consumers. The "tabloid TV" news genre is a relatively new phenomenon in Zambia and in the African context in general. This study is an investigation of the rise in popularity of the Zambian television station, Muvi TV. It is a reception study of Lusaka (capital city) viewers, particularly the working class community, who make up the majority of the TV stations' audience. Members of this social group who have hitherto been marginalised from mainstream media discourses were interviewed. In particular, the study explores the meanings obtained from the content of Muvi TVs' tabloidised main evening news and its relevance to their everyday lived experiences. The TV station gives prominence to "micro-politics of everyday life", alongside "serious" stories albeit in a more lurid, sensationalised and personalised manner. In undertaking this investigation, the study draws primarily on qualitative in-depth interviews - focus group and individual. These techniques unearth the manner in which the viewers decode the messages and appropriate the meanings into their lived experiences. The study establishes that the popularity of Muvi TV is due to the emphasis on human-interest stories epitomised by tabloid journalism values. The working class majority is able to relate and identify with these stories, and attaches greater believability to the station's news as compared to the public broadcaster, the Zambia National Broadcasting Corporation (ZNBC). As such, Muvi TV can be seen to fulfil a political function despite its sensationalised approach.
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Investigating the relationship between sustainability and farmer decision-making: a qualitative study of maize farmers in Mpumalanga, South Africa
- Authors: Grewar, Robert
- Date: 2011
- Subjects: Sustainable agriculture -- Research -- South Africa Agriculture -- South Africa -- Decision making Corn -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:785 , http://hdl.handle.net/10962/d1003906
- Description: The goal of the research paper was to understand the complex relationship between the issue of sustainability and maize farmers’ decision-making processes. The aim is to shed light on the realities experienced by maize farmers in terms of how sustainability impacts on the decisions they make and how the decisions they make impact on sustainability. The importance of the research lies in the current state of affairs in the world in terms of the current economic recession, overpopulation, dire poverty and hunger, and the poor state of the environment. If humankind is to continue its existence on Earth in a happy, healthy world, something is going to have to give. In order for this to happen, people need to start grappling with the concept of sustainability. Focusing on sustainability as a whole is likely to end in despair. However, breaking the problem down into its component pieces will allow people to influence the particular sector in which they operate. It is therefore imperative for research into sustainability to be undertaken in all sectors of society and the economy. Agriculture presents an excellent research area due to its intrinsic link with the environment, society and the economy. Agriculture and its wellbeing is inextricably tied to environmental health. Healthy plants and animals will not grow in unhealthy conditions. Society is to a large degree dependent on agriculture for food, agriculture therefore has a significant impact on social order and function. Agriculture is one of the primary contributors to GDP, particularly in poor and developing nations. As a result, agriculture has an important role to play in ensuring economic sustainability. In order to engage with sustainability from an agricultural perspective it was decided to engage on the farmer-level. Gaining an understanding of their reality in terms of what motivates their decisions is key to understanding the relationship between agriculture and sustainability. Three maize farmers in Mpumalanga, South Africa, were interviewed with the aim of collecting qualitative data and then analysing the data using thematic analysis. The methodology employed enabled the researcher to uncover patterns in the data that constituted themes across the interviews. The following themes emerged: Theme 1: Economic factors are the primary decision driver. This is primarily due to the extent of the financial risk experienced by farmers as a result of market risk, production risk, finance risk, and rising input costs. This results in economic considerations superseding environmental or social concerns in farmers’ decisions. This has a negative impact on the overall sustainability of the farming operation. Theme 2: There has been a decrease in the number of family-run farms. This is attributable to a number of factors including economic failure, fear of loss of land due to land-reform policies, as well as crime. Family-run farms tend to have a greater focus on sustainability due to the vested interest in the next generation taking over the farm. The corporate farming operations that are taking over the farms tend to be more focussed on short-term gains in order to satisfy shareholders. Theme 3: Mechanisation is preferable to manual labour. There has been an alarming decrease in the number of labourers employed on farms. Farmers say this is due to two factors. Firstly, machines are more efficient than labour. Secondly, restrictive labour laws have made famers less keen to employ people. The net effect of these two factors is that unemployment is rising. This has negative consequences for society, the economy, and the environment. Theme 4: Farmers believe they do very little environmental damage. This results in decisions being made that do not consider environmental wellbeing other than soil health. This is because farmers see healthy soil as an integral input that optimises economic performance. Farmers tend to prioritise economic factors in their decisions more than environmental or social factors. This results in an unsustainable perspective. The only ways in which this is likely to change is if the financial risk associated with agriculture is decreased, or if farmers are given financial incentive to change their ways. In order to deal with this issue it is necessary for further research to be conducted. Research needs to be conducted to confirm the results of this study. It is important to know whether the results pertain only to maize farmers in Mpumalanga or whether most farmers in South Africa, and indeed the world, face similar problems. Research should also be conducted to propose policies or procedures to reduce financial risk in agriculture. Research should focus on reducing market risk and reducing input costs, possibly via subsidisation.
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Investigating the role of heat shock proteins (Hsps) 40, 70 and 90 in the life cycle of Theiler's murine encephalomyelitis virus (TMEV)
- Authors: Mutsvunguma, Lorraine Zvichapera
- Date: 2011
- Subjects: Heat shock proteins , Picornaviruses , Encephalomyelitis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3966 , http://hdl.handle.net/10962/d1004025 , Heat shock proteins , Picornaviruses , Encephalomyelitis
- Description: Introduction: Picornaviruses are a family of RNA viruses which are economically and clinically significant. Like many other viruses, picornaviruses utilise host cell machinery to facilitate their replication and assembly, including heat shock proteins (Hsps). The aim of this research was to investigate the role of Hsp40, Hsp70 and Hsp90 during picornavirus infection using the cardiovirus, Theiler’s murine encephalomyelitis virus (TMEV), as a study model. Methodology: Picornavirus VP1 capsid proteins were analysed by multiple sequence alignment and multiple structural comparisons. Protein domain architecture was used to analyse Hsp90 cellular and viral client proteins. Effects of Hsp90 inhibitors, novobiocin and geldanamycin, on TMEV growth in BHK-21 cells was observed over a 48hr period. Localisation of Hsp40, Hsp90 and Hsp70 in TMEV-infected BHK-21 cells was investigated by indirect immunofluorescence and confocal microscopy. Results and Discussion: VP1 proteins of picornaviruses are highly divergent within the family at the amino acid level, which might be linked to the protein’s function in determining virus tropism and antibody neutralisation. An eight-stranded anti-parallel beta-barrel structure was found conserved in the VP1 protein structures which might be linked to the highly conserved picornavirus capsid assembly process. Absence of a common protein domain between Hsp90 viral and cellular client proteins that might be functionally connected to Hsp90, suggests that Hsp90 most likely recognises surface features rather than sequence motifs/patterns. The Hsp90 inhibitors, novobiocin and geldanamycin, had a negative effect on virus growth as virus-induced cytopathic effect was not observed in treated cell after 48hrs. TMEV 2C protein was detected by Western analysis in infected cell lysates treated with geldanamycin but not novobiocin, suggesting novobiocin affects the translation or processing of TMEV 2C. Immunofluorescence analysis of TMEV-infected cells showed a relocalisation of Hsp40 into the nucleus during infection. Overlap of Hsp40 and TMEV P1 was observed in the perinuclear region, suggesting colocalisation between these proteins. Hsp70 converged around the replication complex during infection but did not overlap with TMEV 2C. Hsp90 concentrated in the region of the replication complex where it overlapped with TMEV 2C and this redistribution was found to be dependent on the stage of infection. The overlap between Hsp90 and TMEV 2C signals observed, suggested colocalisation between the two proteins. Conclusion: This study identified Hsp90, Hsp70 and Hsp40 as possible host factors required in TMEV replication.
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Investigation into the extended capabilities of the new DPS-4D ionosonde
- Authors: Ssessanga, Nicholas
- Date: 2011
- Subjects: Ionosondes , Ionosphere , Ionosphere -- Observations -- South Africa -- Hermanus (Cape of Good Hope) , Ionosphere -- Research -- South Africa -- Hermanus (Cape of Good Hope)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5472 , http://hdl.handle.net/10962/d1005257 , Ionosondes , Ionosphere , Ionosphere -- Observations -- South Africa -- Hermanus (Cape of Good Hope) , Ionosphere -- Research -- South Africa -- Hermanus (Cape of Good Hope)
- Description: The DPS-4D is the latest version of digital ionosonde developed by the UMLCAR (University of Massachusetts in Lowell Center for Atmospheric Research) in 2008. This new ionosonde has advances in both the hardware and software which allows for the promised advanced capabilities. The aim of this thesis was to present results from an experiment undertaken using the Hermanus DPS-4D (34.4°S 19.2°E, South Africa), the first of this version to be installed globally, to answer a science question outside of the normally expected capabilities of an ionosonde. The science question posed focused on the ability of the DPS-4D to provide information on day-time Pc3 pulsations evident in the ionosphere. Day-time Pc3 ULF waves propagating down through the ionosphere cause oscillations in the Doppler shift of High Frequency (HF) radio transmissions that are correlated with the magnetic pulsations recorded on the ground. Evidence is presented which shows that no correlation exists between the ground magnetic pulsation data and DPS-4D ionospheric data. The conclusion was reached that although the DPS-4D is more advanced in its eld of technology than its predecessors it may not be used to observe Pc3 pulsations.
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Investigation of learning in an environmental skills programme: a case study of workers' training in the Department of Environmental Affairs Expanded Public Works Project
- Authors: Giqwa, Nomfundiso Louisa
- Date: 2011
- Subjects: South Africa -- Department of Environmental Affairs Environmental education -- Study and teaching -- South Africa Environmental education -- Activity programs -- South Africa Environmental education -- Evaluation -- South Africa Environmental education -- Curricula -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1636 , http://hdl.handle.net/10962/d1003518
- Description: This research project examines a case of environmental training for workers in the Expanded Public Works Programme, a poverty relief programme operating in South Africa (EPWP). It is constituted as an interpretive case study, and explores what workers learn and how they learn in an environmental skills programme. The study also examines the context of learning. In accordance with education and training policy, what learners are meant to learn is articulated in unit standards registered on the South African Qualifications Authority website. The unit standards are used to design curricula and learning programmes which are registered as environmental skills programmes by Sector Education and Training Authorities (SETAs). For the conservation sector the SETA is the Tourism and Hospitality Education and Training Authority (THETA). To develop an understanding of what learners learn, I considered the content, concepts, skills, values and attitudes contained in the unit standards, and then considered the actual learning taking place during the training programme focusing on three unit standards. Data was generated from semi-structured interviews with facilitators, focus group interviews with learners, observations of teaching and learning interventions and document analysis of EPWP, training and skills development policy documents, registered unit standards for the skills programme, and learning support materials produced by the provider implementing the training. The study notes that there is learning taking place within the training implemented through environmental skills programmes. The training is influenced by a number of diverse contextual factors namely policy factors, historical contextual factors, the economic context and diverse literacy levels. Learning interactions involve a variety of social interactions, activities and practices between learners and learners, and learners and facilitators. The main finding of the study is that the training programme’s major emphasis is on concepts and content, and social and learning skills, and values and attitudes. The prominence of social skills masks a neglect of practical workplace related skills which make up a strong focus of the unit standards. This, the study shows, is related to a lack of engagement with workplace learning, which in turn is linked to a disjuncture between policy and practice, where workers working in the EPWP programme are meant to benefit from training, but in this case it was found that community members, who were not working in the programme were being offered training. It was therefore not possible for them to develop the applied workplace skills, which were also meant to facilitate increased employability, as this is one of the key objectives of the EPWP programme. Based on the insights raised by the research findings the study made recommendations that the programme consider the following to recover the situation: to develop strategies that allow for longer term training frameworks so that learners can be trained on full qualifications so that they may qualify and benefit more substantively from the training in terms of employability skills. Facilitators in the programme need to be trained so that they can develop materials that address practical skills, values, attitudes, critical reflections and actions. Monitoring of training needs to be given preference both at materials development level and implementation level.
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Investigation of photosensitising behaviour of Ni, Pd and Pt phthalocyanines towards phenolic pollutants
- Authors: Ogunbayo, Taofeek Babatunde
- Date: 2011
- Subjects: Phthalocyanines Pollutants Photochemistry Photosensitizing compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4321 , http://hdl.handle.net/10962/d1004979
- Description: Syntheses of various octasubstituted open-shell (Ni(II), Pd(II) and Pt(II)) metallophthalocyanines and their metal-free analogues have been carried out. Spectroscopic characterizations, photophysical and photochemical studies were carried out to determine the effects of these metals on the molecules using the metal-free phthalocyanine analogues as benchmark. Metal-binding studies of few thio-derivatised phthalocyanines were done to increase the number of palladium metal on the phthalocyanine ligands and determine the effect of increasing number of this metal on phthalocyanine properties. Palladium (PdPc) and platinum phthalocyanines (PtPc) gave good triplet and singlet oxygen quantum yields making them suitable for further investigation in application as photosensitisers. Using 4-nitrophenol as model pollutant, photosensitization reactions were carried out under homogenous and heterogeneous conditions. The reactions were monitored using UV-vis spectroscopy. The MPcs were adsorbed on functionalized single wall carbon nanotube (SWCNT-COOH) to form heterogeneous photosensitizers with PtPc failing to adsorb on the SWCNT-COOH. Under the heterogeneous condition, all the PdPcs photosensitization kinetics was consistent with Langmuir-Hinshelwood reaction model. The best photosenstiser, β-palladium dodecylthio phthalocyanine was also deployed in sensitization of oxidation of 4-chlorophenol and pentachlorophenol under homogenous and heterogeneous conditions to establish the ability of the molecules to sensitize oxidation of wide range of phenolic pollutants. Identifications of the products of the reactions were conducted using gas chromatography and high pressure liquid chromatography (HPLC) hyphenated with mass analyzer (LC-MS). Mechanisms of all the reactions were investigated and all the complexes, in spite of reduced lifetime resulting from open-shell nature of the metals, sensitized the reactions through singlet oxygen mediated pathway. All the heterogeneous sensitisers were recyclable in the 4- nitrophenol oxidation but β-palladium dodecylthio phthalocyanine proved unrecyclable in the oxidation of pentachlorophenol.
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Investigations of the assessment of bioequivalence of topical clotrimazole products using a dermatopharmacokinetic approach
- Authors: Parfitt, Natalie Rae
- Date: 2011 , 2010-07-05
- Subjects: Dermatopharmacology , Drugs -- Therapeutic equivalency , Antifungal agents , Therapeutics, Cutaneous and external
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3840 , http://hdl.handle.net/10962/d1007659 , Dermatopharmacology , Drugs -- Therapeutic equivalency , Antifungal agents , Therapeutics, Cutaneous and external
- Description: The specialised nature of the stratum corneum makes it an efficient barrier to foreign substances, including drug molecules. Therefore, cutaneous drug absorption is a slow and complex process of which stratum corneum penetration is the rate limiting step. The rate and extent of stratum corneum penetration by a drug compound depends greatly on the presence of penetration enhancing/retarding excipients and therefore the clinical outcomes of a product rely greatly on the components and quality of the formulation. Hence, establishing bioequivalence between topical products is crucial to ensure that patients receiving multisource drug products are assured of the same efficacy and safety as the brand product. Since locally acting topical formulations do not target the systemic circulation, conventional methods of assessing bioequivalence using plasma levels are not appropriate. Consequently, the current regulatory guidelines require comparative clinical trials to be carried out to show bioequivalence between topical products. As these studies are very expensive and time consuming, the development of a more direct and relatively rapid and inexpensive method for determining bioequivalence between topical products is required. Clotrimazole is an anti-fungal agent where the target site of action is in the stratum corneum. In this work, tape stripping, which involves the sampling of stratum corneum, was investigated as a tool for the determination of bioequivalence between topical clotrimazole products. The tape stripping method involved the analysis of each tape strip individually and standardization of stratum corneum thickness between subjects was carried out using TEWL measurements. This approach provided detailed information regarding the amount of clotrimazole present in the stratum corneum as well as the extent of drug penetration. Prior to the tape stripping studies an HPLC method was developed for the quantitative analysis of clotrimazole from the tape strip samples. This method was shown to be accurate and reproducible across the required range. It was also shown to be selective for clotrimazole in the presence of possible interfering substances such as those present in the tape adhesive and also skin components. The bioequivalence studies were conducted using a single “uptake” time point. In order to determine an appropriate dose duration for these studies a novel approach was employed, involving a preliminary dose duration study. For the bioequivalence investigations, Canesten® Topical cream was used as both test and reference products to determine if the method was capable of showing bioequivalence. Subsequently, Canesten® Topical cream was also compared to a 1% gel formulation to determine if the method could detect formulation differences. The conventional BE limits of 0.8 – 1.25 were used for the assessment of BE, however, the clinical relevance of using these limits for dermal studies is debatable since they are derived from oral pharmacokinetic studies. Therefore, the data from the tape stripping investigations were also assessed using more realistic limits of 0.75 – 1.33 and even 0.7 – 1.44. In addition to the tape stripping studies a novel method of determining the amount of drug present in the stratum corneum, the “Residual Method”, was investigated. This method involved assaying the amount of clotrimazole found in the residual formulation after a specified dose duration had elapsed and subtracting that amount from the amount of clotrimazole initially applied. The results of tape stripping investigations showed that, if the study is sufficiently powered, tape stripping may be used to determine bioequivalence according to the conventional limits, as well as possibly detect formulation differences between different clotrimazole products. Bioequivalence assessment using the widened intervals showed that fewer subjects were required to achieve a sufficient statistical power. The variability associated with this method was acceptable and tape stripping may therefore have the potential to be used as a BE tool in a regulatory setting for clotrimazole or other antifungal topical formulations. The “Residual Method” also showed promising results as a bioequivalence tool, but further investigation and extensive validation of this method is required before it can be suggested as a regulatory method. The results of these studies have clearly indicated that tape stripping has the potential to be used as an alternative to comparative clinical trails for the assessment of bioequivalence between clotrimazole formulations and also to assess bioequivalence between other antifungal products.
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Learning commercial beekeeping: two cases of social learning in southern African community natural resources management contexts
- Authors: Masara, Christopher
- Date: 2011
- Subjects: Bee culture Bee culture -- Africa, Southern Social learning -- Africa, Southern Natural resources -- Africa, Southern--Management Natural resources, Communal -- Africa, Southern Conservation of natural resources -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1664 , http://hdl.handle.net/10962/d1003547
- Description: Community Based Natural Resources Management (CBNRM) in southern Africa has gained an important role in alleviating poverty and conserving natural resources. The attention and funding CBNRM is receiving from governments, non-governmental organisations and donors is seen as one way to strengthen civil society‟s involvement in decision-making and participating in activities that contribute to a sustainable livelihood, whilst at the same time learning in their social contexts to adapt and care for the ever changing environment characterised by constraints, challenges, contradictions, new opportunities for learning and change. This study focuses on social learning in commercialisation of natural resource products in two case studies of commercial beekeeping in rural southern African contexts. In this study social learning entails a process of qualitative change taking place in a social context for the purpose of personal and social adaptation. This perspective is useful in this study as learning in the two cases, Hluleka in South Africa and Buhera in Zimbabwe involved the transition beekeeping.from traditional honey harvesting practices and subsistence beekeeping to commercial beekeeping. This study is informed by two related theoretical perspectives namely Cultural Historical Activity Theory (CHAT) and Social Learning Theory. CHAT was used as conceptual and methodological framework to inform the first phase of data gathering and analysis processes; as well as second phase data gathering. In the first phase, I gathered data through semistructured interviews, document reviews and observations to identify problems, challenges and critical incidents in learning commercial beekeeping, technically known as tensions and contradictions within the CHAT framework. These tensions and contradictions, surfaced through analysis of first phase data were used as "mirror data‟ in Intervention Workshops within CHAT's process of Developmental Work Research, which supports social learning in response to tensions and contradictions in workplace activity. Use of mirror data provided a basis for dialogue and the modelling of new solutions to identified contradictions. To interpret the social learning processes resulting from these interactions, I drew on Wals' (2007) analytical lenses, through which I was able to monitor social learning processes that emerged from the Intervention Workshop dialogues while beekeepers modelled new solutions to contradictions in learning commercial beekeeping. The findings of the study revealed that social learning in commercial beekeeping is internally and externally influenced by socio-cultural, political and economic complexities. Social learning in Intervention Workshops was supported by different knowledge bases of participants, in this study these are beekeepers, extension officers, trainers and development facilitators. Such knowledge bases were the source of information for learning and constructing model solutions. The study also revealed that learning in CBNRM workplaces can be observed across the development processes, and CHAT as a methodological tool and Wals‟ (2007) analytical tool are complementary and can be used in researching social learning in other CBNRM workplaces. The study contributes in-depth insight into participatory research and learning processes, especially within the context of CBRM in southern Africa. It gives some empirical and explanatory insight into how change-oriented social learning can emerge and be expanded in Education for Sustainable Development. It also provides learning and extension tools to work with contradictions that arise from socio-cultural and historical dimensions of learning commercialisation of natural resources in southern African context. Its other key contribution is that it provides further insight into the mobilisation of human agency and reflexivity in change oriented social learning processes of commercialisation of sustainable natural resources products and poverty alleviation processes that are critical for responding to socioecological issues and risks and development challenges in southern Africa.
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Lumberjacks and hoodrats: negotiating subject positions of lesbian representation in two South African television programmes
- Authors: Donaldson, Natalie
- Date: 2011
- Subjects: Lesbianism on television -- Research -- South Africa , Lesbians -- Research -- South Africa , Gay rights -- Research -- South Africa , Television actors and actresses -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2964 , http://hdl.handle.net/10962/d1002473 , Lesbianism on television -- Research -- South Africa , Lesbians -- Research -- South Africa , Gay rights -- Research -- South Africa , Television actors and actresses -- Research -- South Africa
- Description: With the inclusion of sexual orientation in the Equality clause of the post-Apartheid constitution which demands equal rights and protection for all individuals regardless of sexual orientation, South Africa has been praised as one of the most liberal countries in the world. Because of this legal equality, gay and lesbian experiences have become a lot more visible in every day South African lives. This includes visibility in South African television programmes and film. Today, a number of South African produced television programmes have included at least one lesbian character in their storyline and many LGBTIQ activist organisations have deemed this increased visibility as a positive step for LGBTIQ rights. However, discriminatory discourses such as same-sex sexualities as 'un-African ' and unnatural, which often result in brutal hate crimes against LGBTIQ individuals (such as corrective rape), contribute to the social and cultural intolerance of same-sex sexualities. South African research into the lives of lesbian women has often related lesbian experience to that of gay men or has focused on lesbian women as victims of corrective rape and oppressive practices at the hands of the dominant heteronormative culture. This research was a discursive reception study, using three focus group discussions with self-identified lesbian audiences (black and white). The study explored how this audience received (interpreted/talked about) the available fictional representations of 'black' lesbian women and 'white' lesbian women in three clips from two South African television programmes, Society and The Mating Game. Using Wetherell's (1998) critical discursive psychology approach, this research focused on examining the 1) Subject positions made available in/by these representations; 2) Interpretive repertoires used by the audience in appropriating and/or negotiating and/or reSisting these subject positions; and 3) Ideological dilemmas experienced by participants in this negotiation process. The predominant subject positions made available in these representations were differentiated according to binary racial categories of white lesbian women and black lesbian women. For example, participants positioned white lesbian women as "lumberjacks" and "tomboys" while black lesbian women were positioned as "township lesbians" and "hood rats". In working with these subject positions, participants drew on interpretative repertoires of othering and otherness as well as interpretative repertoires of survival. In negotiating with these subject positions and others found in the discussions, ideological dilemmas often arose when participants found themselves having to draw on interpretative repertoires which extend from a heteronormative discourse. These kinds of interpretative repertoires included religion, nature, and compromise which contradicted and created a troubled position when used in relation to the participants' lesbian sexualities. Therefore, when the ideological dilemma and troubled position became apparent, participants had to work to repair the troubled position by justifying their use of these heteronormative interpretative repertoires.
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Male and female cardiovascular risk in an urban, black working population
- Authors: Jackson, Lindsay May
- Date: 2011
- Subjects: Cardiovascular system -- Diseases -- South Africa -- Grahamstown , Obesity -- South Africa -- Grahamstown , Hypertension -- South Africa -- Grahamstown , Hypercholesteremia -- South Africa -- Grahamstown , Diabetes -- South Africa -- Grahamstown , Lifestyles -- Health aspects -- South Africa -- Grahamstown , Health behavior -- South Africa -- Grahamstown , Health attitudes -- South Africa -- Grahamstown , Black people -- South Africa -- Grahamstown -- Health and hygiene
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5127 , http://hdl.handle.net/10962/d1005205 , Cardiovascular system -- Diseases -- South Africa -- Grahamstown , Obesity -- South Africa -- Grahamstown , Hypertension -- South Africa -- Grahamstown , Hypercholesteremia -- South Africa -- Grahamstown , Diabetes -- South Africa -- Grahamstown , Lifestyles -- Health aspects -- South Africa -- Grahamstown , Health behavior -- South Africa -- Grahamstown , Health attitudes -- South Africa -- Grahamstown , Black people -- South Africa -- Grahamstown -- Health and hygiene
- Description: The aim of this research project was to assess and compare cardiovascular disease (CVD) risk in black males and females from an urban, working population in the Makana (Grahamstown) region of the Eastern Cape, South Africa. Two-hundred and ninety one individuals (males: n = 143, females: n = 148) with a mean age of 42.6 (±8.1) years were voluntarily recruited from the greater urban Makana (Grahamstown) area. Eight Cardiovascular disease (CVD) risks were assessed: stature and mass were obtained in order to calculate body mass index (BMI) (mass/stature2). Obesity, defined as a morphological risk, was classified according to the World Health Organisation (WHO) BMI criteria (BMI>30kg.m-2), as well as according to measures of waist circumference (WC) and body composition. Hypertension, hypercholesterolemia and type II diabetes, were grouped as cardiovascular (CV) risks. Hypertension was defined as a blood pressure greater than 140/90mmHg (JNC-7); hypercholesterolemia, as total cholesterol greater than 6.2mmol.L-1 (NCEP); and type II diabetes, as total glucose greater than 12mmol.L-1 (WHO). Physical activity, diet, tobacco use, and alcohol consumption and dependence were grouped as lifestyle-related risks. These were assessed by means of self-reporting through the use of various validated questionnaires. Finally, self-reporting of obesity, hypertension, hypercholesterolemia and type II diabetes was assessed, in addition to perception questions on individuals’ perceived body shape and size (Ziebland figures). Self-reported and perceived responses were then compared to actual measures. Females were significantly (p<0.001) heavier than the males (92.7kg compared to 72.1kg) and had significantly (p<0.001) higher BMIs than their male counterparts (37.6kg.m-2 compared to 25.7 kg.-2). They also recorded significantly (p<0.001) higher waist circumference (WC) values and had significantly (p<0.001) higher percentage and total body fat. Significantly (p<0.001) more females were obese (81%) compared to males (17%). While a higher percentage of males (25 % compared to 22%) presented with stage I hypertension (≥140/90mmHg, <160/95mmHg), significantly (p<0.05) more females (14% compared to 8%) presented with stage II hypertension (>160/95mmHg). The prevalence of hypercholesterolemia at a high level of risk (>6.2mmol.L-1) was relatively low (2.1 % of males, 3.4% of females), but notably more participants (22% of males and 26% of females) presented with the condition at a moderate level of risk (>5mmol.L-1). Type II diabetes was the least prevalent CV risk factor, with no males and only 3% of females presenting with the condition. Males consumed significantly (p<0.05) more in terms of total energy intake (9024 vs. 7234 kJ) and were significantly (p<0.05) more active (3315 compared to 2660 MET-mins.week). A significantly (p<0.05) higher percentage of males smoked (51.1% compared to 3.4%), consumed alcohol (73.4% compared to 46.6%) and were alcohol dependent (40% compared to 33.5%). Both males and females tended to be ignorant of their health status, with both samples under-reporting obesity, hypertension and hypercholesterolemia, while over-reporting type II diabetes. Furthermore, obesity was significantly (p<0.05) underestimated, with both male and female individuals perceiving themselves to be notably smaller than they actually were. Physical activity and diet were important determinants of CVD risk in this black urban sample of individuals. Obesity, in particular central adiposity, was the most notable risk (particularly in females), followed by hypertension (particularly in males). Although some risks presented at a moderate level of risk, a clustering of risk factors was evident in both samples, with 12.6% and 41.2% of males and females presenting with two risk factors, and 2.8% and 8.1% of males and females respectively presenting with three risks.
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Management and the dynamics of labour process: study of workplace relations in an oil refinery, Nigeria
- Authors: Oladeinde, Olusegun Olurotimi
- Date: 2011
- Subjects: Nigerian National Petroleum Corporation Personnel management -- Nigeria Petroleum industry and trade -- Personnel management -- Nigeria Performance -- Management -- Nigeria Industrial relations -- Nigeria Organizational behavior -- Nigeria Total quality management -- Nigeria Labor unions -- Nigeria Petroleum workers -- Nigeria -- Attitudes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3299 , http://hdl.handle.net/10962/d1003087
- Description: The focus of this thesis is on labour-management relations in the Nigerian National Petroleum Corporation (NNPC), Nigeria. The study explores current managerial practices in the corporation and their effects on the intensification of work, and how the management sought to control workers and the labour process. The study explores the experiences of workers and their perception of managerial practices. Evidence suggests that managerial practices and their impacts on workplace relations in NNPC have become more subtle, with wider implications for workers’ experience and the labour process. Using primary data obtained through interviews, participant observation, and documentary sources, the thesis assesses how managerial practices are varieties of controls of labour in which workers’ consent is also embedded. This embeddedness of the labour process generates new types of worker subjectivity and identity, with significant implications for labour relations. The study suggests that multiple dimensions of workers’ sense-making reflect the structural and subjective dimensions of the labour process. In NNPC, the consequence of managerial practices has been an emergence of a new type of subjectivity; one that has closely identified with the corporate values and is not overtly disposed towards resistance or dissent. While workers consent at NNPC continues to be an outcome of managerial practices, the thesis examined its implications. The thesis seeks to explain the effects of managerial control mechanisms in shaping workers’ experience and identity. However, the thesis shows that while workers remain susceptible to these forms of managerial influence, an erasure or closure of oppositions or recalcitrance will not adequately account for workers’ identity-formation. The thesis shows that while managerial control remains significant, workers inhabit domains that are ‘unmanaged’ and ‘unmanageable’ where ‘resistance’ and ‘misbehaviour’ reside. Without a conceptual and empirical interrogation, evidence of normative and mutual benefits of managerial practices or a submissive image of workers will produce images of workers that obscure their covert opposition and resistance. Workers ‘collude’ with the ‘hubris’ of management in order to invert and subvert managerial practices and intentions. Through theoretical reconceptualization, the thesis demonstrates the specific dimensions of these inversions and subversions. The thesis therefore seeks to re-insert “worker-agency” back into the analysis of power-relations in the workplace; agency that is not overtly under the absolute grip of managerial control, but with a multiplicity of identities and multilevel manifestations.
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Marine anti-malarial isonitriles : a synthetic and computational study
- Authors: Adendorff, Matthew Ralph
- Date: 2011 , 2010-05-17
- Subjects: Isocyanides , Isocyanates , Marine pharmacology , Antimalarials , Antimalarials -- Development , Drug development
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4398 , http://hdl.handle.net/10962/d1006674 , Isocyanides , Isocyanates , Marine pharmacology , Antimalarials , Antimalarials -- Development , Drug development
- Description: The development of Plasmodium falciparum malarial resistance to the current armoury of anti-malarial drugs requires the development of new treatments to help combat this disease. The marine environment is a well established source of potential pharmaceuticals. Of interest to us are isonitrile, isocyanate and isothiocyanate compounds isolated from marine sponges and molluscs which have exhibited nano-molar anti-plasmodial activities. Through quantitative structure-activity relation studies (QSAR), a literature precedent exists for a pseudoreceptor model from which a pharmacophore for the design of novel anti-malarial agents was proposed. The current theory suggests that these marine compounds exert their inhibitory action through interfering with the heme detoxification pathway in P. falciparum. We propose that the computational methods used to draw detailed conclusions about the mode of action of these marine compounds were inadequate. This thesis addresses this problem using contemporary computational methodologies and seeks to propose a more robust method for the rational design of new anti-malarial drug compounds that inhibit heme polymerization to hemozoin. In order to investigate the interactions of the marine compounds with their heme targets, a series of modern computational procedures were formulated, validated and then applied to theoretical systems. The validations of these algorithms, before their application to the marine compound-heme systems, were achieved through two case studies. The first was used to investigate the applicability of the statistical docking algorithm AutoDock to be used for the exploration of conformational space around the heme target. A theoretical P. falciparum 1-deoxy-D-xylulose-5-phosphate reductoisomerase (PfDXR) enzyme model, constructed by the Biochemistry Department at Rhodes University, provided the ideal model to validate the AutoDock program. The protein model was accordingly subjected to rigorous docking simulations with over 30 different ligand molecules using the AutoDock algorithm which allowed for the docking algorithm’s limitations to be ascertained and improved upon. This investigation facilitated the successful validation of the protein model, which can now be used for the rational design of new PfDXR-inhibiting anti-plasmodial compounds, as well as enabling us to propose an improvement of the docking algorithm for application to the heme systems. The second case study was used to investigate the applicability of an ab initio molecular dynamics algorithm for simulation of bond breaking/forming events between the marine compounds and their heme target. This validation involved the exploration of intermolecular interactions in a naturally occurring nonoligomeric zipper using the Car-Parrinello Molecular Dynamics (CPMD) method. This study allowed us to propose a model for the intermolecular forces responsible for zipper self-assembly and showcased the CPMD method’s abilities to simulate and predict bond forming/breaking events. Data from the computational analyses suggested that the interactions between marine isonitriles, isocyanates and isothiocyanates occur through bond-less electrostatic attractions rather than through formal intermolecular bonds as had been previously suggested. Accordingly, a simple bicyclic tertiary isonitrile (5.14) was synthesized using Kitano et al’s relatively underutilized isonitrile synthetic method for the conversion of tertiary alcohols to their corresponding isonitriles. This compound’s potential for heme detoxification inhibition was then explored in vitro via the pyridine-hemochrome assay. The assay data suggested that the synthesized isonitrile was capable of inhibiting heme polymerization in a similar fashion to the known inhibitor chloroquine. Attempts to synthesize tricyclic analogues of 5.14 were unsuccessful and highlighted the limitation of Kitano et al’s isonitrile synthetic methodology.
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Modelling the relationship between flow and water quality in South African rivers
- Authors: Slaughter, Andrew Robert
- Date: 2011
- Subjects: Water quality -- Measurement -- South Africa Water quality -- Mathematical models -- South Africa Streamflow -- South Africa Stream measurements -- Mathematical models -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6039 , http://hdl.handle.net/10962/d1006196
- Description: The National Water Act (Act 36 of 1998) provides for an ecological Reserve as the quantity (flow) and quality of water needed to protect aquatic ecosystems. While there are methods available to quantify the ecological Reserve in terms of flow, methods of linking flow to water quality are lacking. Therefore, the research presented in this thesis investigated various modelling techniques to estimate the effect of flow on water quality. The aims of the research presented in this thesis were: Aim 1: Can the relationship between flow and water quality be accurately represented by simple statistical models? Aim 2: Can relatively simple models accurately represent the relationship between flow and water quality? Aim 3: Can the effect of diffuse sources be omitted from a water quality model and still obtain realistic simulations, and if so under what conditions? Aim 4: Can models that solely use historical monitoring data, accurately represent the relationships between flow and water quality? In Chapter 3, simple Q-C regressions of flow and water quality were investigated using Department of Water Affairs (DWA) historical monitoring data. It was found that while flow versus salinity regressions gave good regression fits in many cases, the Q-C regression approach is limited. A mechanistic/statistical model that attempted to estimate the point and diffuse signatures of nutrients in response to flow was developed in Chapter 4 using DWA historical monitoring data. The model was verified as accurate in certain case studies using observed point loading information. In Chapter 5, statistical models that link land cover information to diffuse nutrient signatures in response to flow using DWA historical data were developed. While the model estimations are uncertain due to a lack of data, they do provide an estimation of the diffuse signature within catchments where there is flow and land cover information available. Chapter 6 investigates the extension of an existing mass-balance salinity model to estimate the effect of saline irrigation return flow on in-stream salinity. The model gave accurate salinity estimates for a low order stream with little or no irrigation within its catchment, and for a permanently flowing river within a catchment used extensively for irrigation. Chapter 7 investigated a modelling method to estimate the reaction coefficients involved in nitrification using only DWA historical monitoring data. Here, the model used flow information to estimate the residence time of nutrients within the studied river reaches. While the model obtained good estimations of nitrification for the data it was applied to, very few DWA data sets were suitable for the model. Chapter 8 investigated the ability of the in-stream model QUAL2K to estimate nutrient concentrations downstream of point and diffuse inputs of nutrients. It was found that the QUAL2K model can give accurate results in cases where point sources dominate the total nutrient inputs into a river. However, the QUAL2K simulations are too uncertain in cases where there are large diffuse source inputs of nutrients as the load of the diffuse inputs is difficult to measure in the field. This research highlights the problem of data scarcity in terms of temporal resolution as well as the range of constituents measured within DWA historical monitoring data for water quality. This thesis in addition argues that the approach of applying a number of models is preferable to applying one model to investigate the research aims, as particular models would be suited to particular circumstances, and the development of new models allowed the research aims of this thesis to be explored more thoroughly. It is also argued that simpler models that simulate a few key processes that explain the variation in observed data, are more suitable for implementing Integrated Water Resource Management (IWRM) than large comprehensive water quality models. From this research, it is clear that simple statistical models are not adequate for modelling the relationship between flow and water quality, however, relatively simple mechanistic models that simulate a limited number of processes and water quality variables, can provide accurate representations of this relationship. Under conditions where diffuse sources are not a major factor within a catchment, models that omit diffuse sources can obtain realistic simulations of the relationship between flow and water quality. Most of the models investigated in this thesis demonstrate that accurate simulations of the relationships between flow and water quality can be obtained using solely historical monitoring data.
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