Movement patterns, stock delineation and conservation of an overexploited fishery species, Lithognathus Lithognathus (Pisces: Sparidae)
- Authors: Bennett, Rhett Hamilton
- Date: 2012
- Subjects: Reef fishes -- Behavior , Endangered species -- South Africa , Fish stock assessment -- South Africa , Fishery management -- South Africa , Fish communities -- South Africa , Sparidae , Lithognathus , Lithognathus -- Growth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5374 , http://hdl.handle.net/10962/d1015709
- Description: White steenbras Lithognathus lithognathus (Pisces: Sparidae) has been a major target species of numerous fisheries in South Africa, since the late 19th century. Historically, it contributed substantially to annual catches in commercial net fisheries, and became dominant in recreational shore catches in the latter half of the 20th century. However, overexploitation in both sectors resulted in severe declines in abundance. The ultimate collapse of the stock by the end of the last century, and the failure of traditional management measures to protect the species indicate that a new management approach for this species is necessary. The species was identified as a priority for research, management and conservation in a National Linefish Status Report. Despite knowledge on aspects of its biology and life history, little is known about juvenile habitat use patterns, home range dynamics and movement behaviour in estuaries. Similarly, the movement and migration of larger juveniles and adults in the marine environment are poorly understood. Furthermore, there is a complete lack of information on its genetic stock structure. Such information is essential for effective management of a fishery species. This thesis aimed to address the gaps in the understanding of white steenbras movement patterns and genetic stock structure, and provide an assessment of its current conservation status. The study adopted a multidisciplinary approach, incorporating a range of methods and drawing on available information, including published literature, unpublished reports and data from long-term monitoring programmes. Acoustic telemetry, conducted in a range of estuaries, showed high site fidelity, restricted area use, small home ranges relative to the size of the estuary, and a high level of residency within estuaries at the early juvenile life stage. Behaviour within estuaries was dominated by station-keeping, superimposed by a strong diel behaviour, presumably based on feeding and/or predator avoidance, with individuals entering the shallow littoral zone at night to feed, and seeking refuge in the deeper channel areas during the daytime. Conventional dart tagging and recapture data from four ongoing, long-term coastal fish tagging projects, spread throughout the distribution of this species, indicated high levels of residency in the surf zone at the late juvenile and sub-adult life stages. Consequently, juvenile and sub-adult white steenbras are vulnerable to localised depletion, although they can be effectively protected by suitably positioned estuarine protected areas (EPAs) and marine protected areas (MPAs), respectively. It has been hypothesized that adult white steenbras undertake large-scale coastal migrations between summer aggregation areas and winter spawning grounds. The scale of observed coastal movements was correlated with fish size (and age), with larger fish undertaking considerably longer-distance coastal movements than smaller individuals, supporting this hypothesis. Given the migratory behaviour of adults, and indications that limited spawning habitat exists, MPAs designed to protect white steenbras during the adult life stage should encompass all known spawning aggregation sites. The fishery is plagued by problems such as low compliance and low enforcement capacity, and alternative management measures, such as seasonal closure, need to be evaluated. Despite considerable conventional dart tagging effort around the coastline (5 782 fish tagged) with 292 recaptures there remains a lack of empirical evidence of fish migrating long distances (> 600 km) between aggregation and spawning areas. This uncertainty in the level of connectivity among coastal regions was addressed using mitochondrial DNA sequencing and genotyping of microsatellite repeat loci in the nuclear genome, which showed no evidence of major geographic barriers to gene flow in this species. Samples collected throughout the white steenbras core distribution showed high genetic diversity, low genetic differentiation and no evidence of isolation by distance or localised spawning. Although historically dominant in several fisheries, analysis of long-term commercial and recreational catch data for white steenbras indicated considerable declines and ultimately stock collapse. Improved catch-per-unit-effort in two large MPAs subsequent to closure confirmed that MPAs can be effective for the protection of white steenbras. However, the current MPA network encompasses a low proportion of sandy shoreline, for which white steenbras exhibits an affinity. Many MPAs do not prohibit recreational shore angling, which currently accounts for the greatest proportion of the total annual catch. Furthermore, EPAs within the juvenile distribution protect a negligible proportion of the total available surface area of estuaries – habitat on which white steenbras is wholly dependent. Despite some evidence of recent increases in abundance in estuaries and the surf zone in certain areas, white steenbras meets the criteria for “Endangered” on the IUCN Red List of Threatened Species, and for “Protected species” status on the National Environmental Management: Biodiversity Act of South Africa. The species requires improved management, with consideration for its life-history style, estuarine dependency, surf zone residency, predictable spawning migrations and its poor conservation status. The multidisciplinary approach provides valuable information towards an improved scientific basis for the management of white steenbras and a framework for research that can be adopted for other overexploited, estuarine-associated coastal fishery species.
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- Date Issued: 2012
Management perceptions regarding skills shortages in gold mines
- Authors: Xingwana, Lumkwana
- Date: 2012
- Subjects: Labor supply--South Africa , Professional employees--South Africa , Occupational training--South Africa , Gold mines and mining--South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9279 , http://hdl.handle.net/10948/d1007959 , Labor supply--South Africa , Professional employees--South Africa , Occupational training--South Africa , Gold mines and mining--South Africa
- Description: The skills shortages in mining and mineral sector had existed for a decade and had a widespread effect on South Africa economy. It affects the level of economic productivity and reduces the country’s capacity to develop a knowledge society. This, in turn, affects the country’s functioning in the global economy. Despite the sector’s best efforts, the shortages continue to grow and threaten the delivery of projects and growth plans. Some researchers contend with the view that the persistence of skills shortages in mining and mineral sector is largely due to entrenched attitudes among both the industry and the community. They claim that employers have the means to change the educational profile of the subsectors by appointing recruits with higher levels of schooling. However, owing to the limited number of higher educated people living in the communities surrounding the mining operations and lack of interest in mining of people with higher levels of education, to name but few, employers are perceived to have a habit of employing people with little skills. The current study was aimed at investigating the impact of skills shortage on organisational performance, propensity to leave, competitive advantage and sustainability, from the management perceptive. The main objective of this study was to incorporate and embed previous research findings and theories into a comprehensive hypothetical model. A hypothetical model showed various factors that may influence skills shortage. Four independent variables (working environment, employment conditions, resources and education and training) were identified as variables that may influence skills shortage; and mediating variable (skills shortage) was also identified as a variable that have potential to affect dependent variables (organisational performance, propensity to leave, competitive advantage and sustainability) of gold mining sector. Furthermore, eight hypotheses were developed to test the relationship between independent, mediating and dependent variables. All these variables were clearly defined and operationalized with various items obtained from measuring instruments used in other similar studies. A purposive sample of 343 respondents was drawn from the population. A seven-point Likert scale and structured questionnaire were administered in person to the respondents and of which 300 were usable and subjected further to several statistical analyses. The validity and reliability of the measuring instrument was evaluated using significant effect p< = 0.001 and Pearson’s correlation test (α = 0.05). Data gathered were fed to and analysed by STATISTICA (version 10) and factor analysis and regression analyses were the statistical procedures used to test the significance of the relationships between the various independent and dependent variables. Consequently, working environment, resources and education and training were three independent variables that were identified as having ability to predict propensity to leave, competitive advantage and sustainability. An attempt was made to establish whether various demographic variables have an influence on mediating and dependent variables through the introduction of gender and position in the organisation while conducting an Analysis of Variance and Multiple linear regressions, but they obtained negative values. The conclusion is that demographic variables do not have over mediating and depended variables. The findings of this study states that with conducive working environment, availability of resources, the high levels of education and training, the country could produce skills that would reduce propensity to leave, drive competitive advantage and sustainability, innovation and entrepreneurship, create competitive advantages and boost employment sustainability.
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- Date Issued: 2012
The relationship between health and safety and human risk taking behaviour in the South African electrical construction industry
- Authors: Du Toit, Willem Johannes
- Date: 2012
- Subjects: Electrical engineering -- Safety measures , Electrical engineering -- Health aspects , Construction industry -- Safety measures , Psychology, industrial
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9691 , http://hdl.handle.net/10948/d1009529 , Electrical engineering -- Safety measures , Electrical engineering -- Health aspects , Construction industry -- Safety measures , Psychology, industrial
- Description: Mankind, and the development of people, exists due to risk-taking behaviour. It is not that humans should not take risks, but rather the ability to identify the magnitude of risk exposure in order that mankind‟s actions would be so selected as to mitigate exposed risk factors, that no harm should befall them. The approach to health and safety (H&S) has always been to manage H&S environmental factors that could have a negative impact on people, capital, and organisational systems. However, the critical component of human risk-taking behaviour that would have a far greater impact has rarely been acknowledged as part of the drivers that increase risk exposure. Human behaviour is a major contributing factor in accident causation. Although human error cannot be completely eliminated, it should be identified and correctly managed according to each individual‟s risk-taking profile. The reason people decide to take certain risks under certain conditions and the effect it has on H&S management systems is a key component to managing organisational risk exposure. To quantify the value of individual risk-taking behaviour could provide management with better opportunities of lowering the organisational risk exposure. Human risk-taking behaviour is influenced by each individual‟s perception of risk. Such perception of risk will influence decisions on risk-taking behaviour, which in turn is influenced by the individual‟s psychological profile and environmental factors, including character and the impact of a cultural environment. The electrical construction and maintenance industry differs from other similar industries in that the physical entity of electricity requires not only sensory perception for the identification and evaluation of risk factors, but also requires specialised knowledge and testing equipment to evaluate the parameters of electrical installation, plant or equipment. Without such competence, direct exposure to most electrical installations could be fatal. The optimum human resource (HR) solution for managing the risk potential of high risk-taking behaviour is the rating and allocation of specific job tasks that can match and limit the individual potential for risk-taking behaviour and the impact on organisational incident statistics. Maintaining and optimising employee job performance enables organisations to better achieve pre-set goals and missions. Such improvements being a catalyst for better job performance by setting limitations on high risk-taking behaviour, that will improve H&S performance by lowering incident rates.
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- Date Issued: 2012
Synthetic and bioactivity studies of antiplasmodial and antibacterial marine natural products
- Authors: Young, Ryan Mark
- Date: 2012
- Subjects: Antibacterial agents Marine natural products Marine pharmacology Plasmodium falciparum Staphylococcus aureus Isocyanides Imidazoles
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4378 , http://hdl.handle.net/10962/d1005043
- Description: This thesis is divided into two parts, assessing marine and synthetic compounds active firstly against Plasmodium falciparum (Chapter 3 and 4) and secondly active against methicillin resistant Staphylococcus aureus (MRSA, Chapter 5). In Chapter 3 the synthesis of nine new tricyclic podocarpanes (3.203-3.207 and 3.209-3.212) from the diterpene (+)-manool is described. Initial SAR study of synthetic podocarpanes concluded that the most active compound was a C-13 phenyl substituted podocarpane (3.204, IC₅₀ 6.6 μM). By preparing analogues with varying halogenated substituents on the phenyl ring (3.209-3.212) the antiplasmodial activity was improved (IC₅₀ 1.4 μM), while simultaneously decreasing the haemolysis previously reported for this class of compounds. Inspired by the antiplasmodial activity of Wright and Wattanapiromsakul’s tricycle marine isonitriles (2.16-2.21 and 2.24-2.27) an unsuccessfully attempt was made to convert tertiary alcohol moieties to isonitrile functionalities in compounds 3.188, 3.204-3.207 and 3.209-3.212. Over a decade ago Wright et al. proposed a putative antiplasmodial mechanism of action for marine isonitriles (2.4, 2.9, 2.15, 2.19 and 2.35) and isothiocyanate (2.34) which involved interference in haem detoxification by P. falciparum thus inhibiting the growth of the parasite. In Chapter 4 we describe how we successfully managed to scale down Egan’s β-haematin inhibition assay for the analyses of small quantities of marine natural products as potential β-haematin inhibitors. Our modified assay revealed that the most active antiplasmodial marine isonitrile 2.9 (IC₅₀ 13 nM) showed total β-haematin inhibition while 2.15 (IC₅₀ 81 nM) and 2.19 (IC₅₀ 31 nM) showed partial inhibition at three equivalents relative to haem. Using contempary molecular modelling techniques the charge on the isonitrile functionality was more accurately describe and the modified charge data sets was used to explore docking of marine isonitriles to haem using AutoDock. In Chapter 5 we describe how a lead South African marine bisindole MRSA pyruvate kinase inhibitor (5.8) was discovered in collaboration with colleagues at the University of British Columbia (UBC) and how this discovery inspired us to design a synthetic route to the dibrominated bisindole, isobromotopsentin (5.20) in an attempt to increase the bioactivity displayed by 5.8. We devised a fast and high yielding synthetic route using microwave assited organic synthesis. We first tested this synthesis using simple aryl glyoxals (5.27-5.32) as precursors to synthesize biphenylimidazoles (5.21-5.26), which later allowed us to synthesize the ascidian natural product 5.111. This method was sucessfully extended to the synthesis of deoxytopsentin (5.33) from an N-Boc protected indole methyl ketone (5.89). We subsequently were able to effectively remove the carbamate protection via thermal decomposition by heating the protected bisindole imidazole (5.90) in a microwave reactor for 5 min under argon. The synthesis of 5.20 resulted in an inseparable mixture of monoprotected and totally deprotected topsentin products, and due to time constraints we were not able to optimise this synthesis. Nonetheless our synthesis of the marine natural product 5.33 which was faster and higher yielding than previously reported routes could be extended to the synthesis of other topsentin bisindoles (5.138-5.140). Work towards this goal continues in our laboratory.
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- Date Issued: 2012
A psycho-educational programme to facilitate the mental health of adolescent girls who are victims of verbal bullying
- Authors: Jacobs, Ruwayda
- Date: 2012
- Subjects: Teenage girls -- Mental health -- South Africa , Psychoanalysis , Bullying
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9946 , http://hdl.handle.net/10948/d1014579
- Description: Bullying appears to be a worldwide phenomenon. It occurs within schools, homes, and in the community too. Bullying is a form of aggressive behaviour. Female bullying is not so easily noticed, as girls hardly ever use physical forms of aggression. Bullying can have a detrimental effect on the mental health of the victim. The victims of bullying experience symptoms of mental discomfort, which include low self esteem, feelings of helplessness, feelings of worthlessness and inferiority, lack of confidence, isolation, self-conscientiousness; and lastly, this can lead to suicide. Some form of intervention is necessary to provide adolescents with skills to combat bullying and help them to become mentally healthy again. The overall goal of the study was to develop, implement and evaluate a psycho-educational programme for female adolescents in a secondary school setting, in order to assist them in coping with bullying. The objectives of the research study were to: Conduct asituational analysis to identify the mental health needs of adolescent girls, as victimsof bullying. Develop a psycho-educational programme to facilitate the promotion of mental health of those adolescent girls who are victims of bullying. Implement the psycho-educational programme to facilitate coping by adolescent girls who are victims of bullying. Assess whether the adolescent girls have benefitted from attending the psycho-educational programme. The researcher used a qualitative, explorative, descriptive and contextual design. The research methodology consisted of four phases. In phase one of the research, a situational analysis was done; and the characteristics of mental discomfort exhibited by the victim were identified. The needs of the adolescent girl who has been bullied have already been described. Phase two involved the development of a psycho-educational programme. The information from the situational analysis was used to develop the conceptual framework. The six concepts in the survey list of Dickoff et al. (1968:422) were described as follows: the recipient is the adolescent girl who has been bullied, the agent is an advanced psychiatric nurse, the context is the community and the secondary school where bullying takes place, the dynamics of the intervention constitute the mental discomfort experienced by the adolescent girl. This is what motivates her to participate in the programme. The procedure was identified as the psycho-educational programme, while the terminus or outcome of the intervention for the adolescent girl would be for her to experience mental health after being exposed to the psycho-educational programme. The relationship between the concepts was used to form the mind map of the conceptual framework. This guided the development of the psycho-educational programme. The content of the programme has already been described. In phase three the psycho-educational programme is implemented and in phase four the programme is evaluated. The psycho-educational programme taught the teenage girls skills and it provided them with knowledge to cope better with the bullying. Attending the programme made the teenagers aware that they needed to change to experience mental health and happiness. The empirical study took place in phase four. The data-gathering method in phase four included the conducting of semi-structured interviews with the adolescent girls who participated in the programme, as well as the teachers of these adolescent girls and their parents. Naïve sketches, reflective journals, observations made and field notes formed part of this database. The data was analyzed by means of Tesch‟s descriptive analysis (in Creswell, 2003:192). The participants had to comment on how they were coping after the implementation of the psycho-educational programme. In conclusion, an intervention in the form of the psycho-educational programme was shown to be beneficial to adolescent girls who were victims of bullying, to assist them in coping with the aftermath of being bullied. Recommendations were made to enhance nursing practice, as well as nursing education and nursing research. Keywords: Adolescent girls, bullying, secondary schools, advanced psychiatric nurse, psycho-educational programme, mental health.
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- Date Issued: 2012
Electrospun nanofibers : an alternative sorbent material for solid phase extraction
- Authors: Chigome, Samuel , Samuel Chigome
- Date: 2012 , 2012-03-26
- Subjects: Nanofibers -- Research Electrospinning -- Research Sorbents -- Research Extraction (Chemistry) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4314 , http://hdl.handle.net/10962/d1004972
- Description: The work described in the thesis seeks to lay a foundation for a better understanding of the use of electrospun nanofibers as a sorbent material. Three miniaturised electrospun nanofiber based solid phase extraction devices were fabricated. For the first two, 10 mg of electrospun polystyrene fibers were used as a sorbent bed for a micro column SPE device (8 mm bed height in a 200 μl pipette tip) and a disk (I) SPE device (5 mm 1 mm sorbent bed in a 1000 μl SPE barrel). While for the third, 4.6 mg of electrospun nylon nanofibers were used as a sorbent bed for a disk (II) SPE device, (sorbent bed consisting of 5 5 mm 350 μm stacked disks in a 500 μl SPE barrel). Corticosteroids were employed as model analytes for performance evaluation of the fabricated SPE devices. Quantitative recoveries (45.5-124.29 percent) were achieved for all SPE devices at a loading volume of 100 μl and analyte concentration of 500 ng ml-1. Three mathematical models; the Boltzmann, Weibull five parameter and the Sigmoid three parameter were employed to describe the break through profiles of each of the sorbent beds. The micro column SPE device exhibited a breakthrough volume of 1400 μl, and theoretical plates (7.98-9.1) while disk (I) SPE device exhibited 400-500 μl and 1.39-2.82 respectively. Disk (II) SPE device exhibited a breakthrough volume of 200 μl and theoretical plates 0.38-1.15. It was proposed that the formats of future electrospun nanofiber sorbent based SPE devices will be guided by mechanical strength of the polymer. The study classified electrospun polymer fibers into two as polystyrene type (relatively low mechanical strength) and nylon type (relatively high mechanical strength).
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- Date Issued: 2012
Photophysicochemical and photodynamic studies of phthalocyanines conjugated to selected drug delivery agents
- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
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- Date Issued: 2012
Media and agriculture in Africa : a case study of agriculture radio programming in Malawi
- Authors: Manda, Levison Zeleza
- Date: 2012
- Subjects: Radio in agriculture -- Malawi , Communication -- Agriculture -- Malawi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:8434 , http://hdl.handle.net/10948/d1020925
- Description: This thesis argues that although participatory communication for development has been extolled to be more effective than the monologic or top-down communication approaches associated with the modernization development paradigm, its influence in making Malawian smallholder farmers adopt radio-mediated innovations and technologies seems to be minimal and ought to be reconsidered for more effective communication for development models. The study used mostly qualitative methodology, with focus group discussions, key informant interviews, and a semi-structured questionnaire to gather verbal and statistical from the primary beneficiaries in order data to understand why three mass media interventions in Malawi had similar effects when only one of them was strictly participatory. It found, inter alia, that in two sites food security was the overriding factor that influenced the community members to adopt radio messages while in the third the participants were mostly driven by the desire to earn money, essentially because the area is food-secure. Thus, participation in radio production was found not to have any significant role in the acceptance and adoption of radio-mediated innovations by the farming communities. Based on the above findings, the study recommends a) an integrated communication for development (IC4D) model that combines top-down information dissemination techniques and participatory communication approaches since the two reinforce more than they oppose each other, and b) the formation of a Communication for Development (C4D) pool fund in Malawi to finance C4D activities. The C4D pool fund is theorised to be resourced by the Malawi government departments, local farmers ‘organisations, international NGOs, and UN bodies such as UNICEF, WHO, and the FAO.
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- Date Issued: 2012
Development of a hydraulic sub-model as part of a desktop environmental flow assessment method
- Authors: Desai, Ahmed Yacoob
- Date: 2012
- Subjects: Hydrologic models -- Research -- South Africa Hydraulic engineering -- South Africa Rivers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6041 , http://hdl.handle.net/10962/d1006200
- Description: Countries around the world have been developing ecological policies to protect their water resources and minimise the impacts of development on their river systems. The concept of ‘minimum flows’ was initially established as a solution but it did not provide sufficient protection as all elements of a flow regime were found to be important for the protection of the river ecosystem. “Environmental flows” were developed to determine these flow regimes to maintain a river in some defined ecological condition. Rapid, initial estimates of the quantity component of environmental flows may be determined using the Desktop Reserve Model in South Africa. However, the Desktop Reserve Model is dependent upon the characteristics of the reference natural hydrology used. The advancements in hydraulic and ecological relationships from the past decade have prompted the development of a Revised Desktop Reserve Model (RDRM) that would incorporate these relationships. The research in this thesis presents the development of the hydraulic sub-model for the RDRM. The hydraulic sub-model was designed to produce a realistic representation of the hydraulic conditions using hydraulic parameters/characteristics from readily available information for any part of South Africa. Hydraulic data from past EWR studies were used to estimate the hydraulic parameters. These estimated hydraulic parameters were used to develop hydraulic estimation relationships and these relationships were developed based on a combination of regression and rule-based procedures. The estimation relationships were incorporated into the hydraulic sub-model of the integrated RDRM and assessments of the hydraulic outputs and EWR results were undertaken to assess the ‘applicability’ of the hydraulic sub-model. The hydraulic sub-model was assessed to be at a stage where it can satisfactorily be incorporated in the RDRM and that it is adequately robust in many situations. Recommendations for future work include the refinement of estimation of the channel forming discharge or the use of spatial imagery to check the maximum channel width estimation. It is also proposed that a future version of the hydraulic sub-model could include flow regime change impacts on channel geomorphology and sedimentology so that flow management scenarios can be more effectively assessed.
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- Date Issued: 2012
Megaherbivores in succulent thicket: resource use and implications
- Authors: Landman, Marietjie
- Date: 2012
- Subjects: Elephants , African elephant , Black rhinoceros , Succulent plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10689 , http://hdl.handle.net/10948/d1007956 , Elephants , African elephant , Black rhinoceros , Succulent plants
- Description: This study aims to develop a predictive understanding of the resource use, impacts and interactions of elephant Loxodonta africana and black rhinoceros Diceros bicornis in the succulent thickets of the Eastern Cape, South Africa. While these megaherbivores typically dominate the biomass, elephant are more abundant, such that their impacts off-set that of all other herbivores. Consequently, this thesis has three main foci: first, developing a mechanistic understanding of the influences of elephant; second, developing predictive insights into elephant impacts on plant communities; finally, an understanding of the knockon-effects of the impacts for coexisting rhinoceros. Thus, by documenting the diet and dietary preferences of elephant, I firstly show that only about 18 percent of the species previously thought vulnerable to herbivory, occur in the diet. This refutes the generally held belief that elephant herbivory is the primary driver of decline among plants, and emphasizes the likely contribution of other mechanisms (e.g. trampling, knock-on-effects, etc.). Thus, the accurate prediction of the impacts caused by elephant requires an understanding of previously marginalized mechanisms. From here, I quantify >50 years of impacts on the thicket shrub community and test their spatial and temporal extent near water. I confirm the vulnerability of thicket to transformation (particularly near water) as the accumulated influences of elephant reduce community composition and structure, and predict that these impacts will eventually bring about landscape-level degradation and a significant loss of biodiversity. Importantly, results show an uneven distribution of effects between elements of this community: from community composition and structure, to the structure of individual canopy species and ecological functioning. While these findings confound our interpretation of the extent of the impacts, it demonstrates the importance of explicitly recognizing biodiversity and heterogeneity for the conservation management of elephant. Finally, I test the consequences of the impacts for coexisting rhinoceros. While I show that this causes rhinoceros to change their foraging strategies in the presence of elephant at high densities, I also show that elephant may facilitate access to food for rhinoceros at reduced densities. These findings indicate the importance of elephant in driving the structure and composition of the thicket shrub community and the consequences of this for coexisting large herbivores. Thus, developing a predictive understanding of the spatial and temporal variations of elephant impacts between elements of biodiversity and the mechanisms driving these changes are key to their management. This implies that the effective conservation management of elephant can only be achieved through the careful, scientific design of monitoring programmes.
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- Date Issued: 2012
Comparative biogeography and ecology of freshwater fishes in the Breede and associated river systems, South Africa
- Authors: Chakona, Albert
- Date: 2012
- Subjects: Freshwater fishes -- South Africa -- Breede River , Freshwater fishes -- South Africa -- Geographical distribution , Freshwater fishes -- Ecology , Feshwater fishes -- Genetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5372 , http://hdl.handle.net/10962/d1015694
- Description: Distribution patterns and levels of genetic diversity in extant taxa are a product of complex palaeogeographic processes and climatic oscillations as well as the species’ intrinsic ecological adaptations. The Cape Floristic Region of South Africa presents a unique system for studying the processes that promote species diversification and distribution patterns. This region has a high degree of endemism of both terrestrial and aquatic biota and is clearly isolated from neighbouring areas by the Cape Fold Mountains and the Great Escarpment. The objective of this study was to firstly examine the ecology of freshwater fishes belonging to the genera Galaxias, Pseudobarbus and Sandelia in the south-western CFR. This was followed by an assessment of the genetic diversity of these taxa. Unique lineages were identified and their distribution was mapped. The work aimed to explore the role of the region’s complex palaeogeographic and climatic history as well as the role of the species’ ecological adaptations in driving lineage diversification and shaping contemporary distribution patterns. The four main components of the study can be summarised as follows: 1. Habitat associations of three widely distributed lineages of Galaxias zebratus Pseudobarbus burchelli and Sandelia capensis were evaluated at multiple localities in minimally disturbed mountain tributaries of the Breede, Duiwenhoks and Goukou River systems. The lineages have distinct habitat associations which were related to differences in their morphological traits. The slender-bodied Galaxias ‘nebula’ and the fusiform-shaped Pseudobarbus ‘Breede’ are capable of exploiting upper reaches with faster water velocity. By contrast, the laterally compressed Sandelia ‘eastern’ is restricted to lower reaches, making this lineage more susceptible to a wide array of impacts. 2. A recently discovered lineage of Galaxias zebratus, (Galaxias ‘nebula’), was found to be capable of tolerating emersion for a prolonged period of time. This is the first time that such capabilities have been documented in an African galaxiid. These adaptations have implications for the interpretation of Galaxias ‘nebula’s wide distribution range. 3. The phylogeography of Galaxias ‘nebula’ across its entire distribution range was investigated using two mitochondrial genes (cytochrome c oxidase subunit I (COI) and cytochrome b (cyt b)). This lineage has a complex evolutionary history that was influenced by both intrinsic and extrinsic factors. Rare events such as episodic drainage connections during Pleistocene and Holocene pluvial periods, possibly augmented by river confluences during periods of lower sea-levels and river capture events seem to be the most credible explanation for the extensive contemporary distribution and the relatively shallow genetic divergence between different river systems. 4. Mitochondrial cyt b sequences were used (i) to assess genetic diversity in G. zebratus, P. burchelli and S. capensis from the south-western CFR and (ii) to determine the roles of intrinsic ecological adaptations and extrinsic landscape and climatic changes in promoting genetic diversification and shaping present day distribution patterns of lineages in the three taxa. Marine incursions during periods of major sea-level transgressions are proposed to have isolated populations in upland refugia, thereby driving allopatric divergence in these species. Subsequent connections of rivers during wetter periods and lower sea-levels are proposed to have facilitated post-speciation dispersal of lineages to attain present day distribution patterns. While detailed morphological studies and further genetic analysis are needed to substantiate the taxonomic status of the newly discovered lineages of Galaxias zebratus, Pseudobarbus burchelli and Sandelia capensis, results of the present study indicate that the south-western CFR represents a previously unrecognised centre of freshwater fish diversity and microendemism in the broader Cape Floristic Region. Accurate identification of lineages and comprehensive mapping of their distribution is a fundamental pre-requisite for ecological studies, assessing conservation status and implementation of appropriate conservation measures.
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- Date Issued: 2012
Development of molecularly imprinted polymer based solid phase extraction sorbents for the selective cleanup of food and pharmaceutical residue samples
- Authors: Batlokwa, Bareki Shima
- Date: 2012
- Subjects: Sorbents -- Research Nanofibers -- Research Aflatoxins -- Research Electrospinning -- Research Extraction (Chemistry) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4309 , http://hdl.handle.net/10962/d1004967
- Description: This thesis presents the development of chlorophyll, cholic acid, aflatoxin B1 molecularly imprinted polymer (MIP) particles and cholic acid MIP nanofibers for application as selective solid phase extraction (SPE) sorbents. The particles were prepared by bulk polymerization and the nanofibers by a novel approach combining molecular imprinting and electrospinning technology. The AFB1 MIP particles were compared with an aflatoxin specific immunoextraction sorbent in cleaning-up and pre-concentrating aflatoxins from nut extracts. They both recorded high extraction efficiencies (EEs) of > 97 % in selectively extracting the aflatoxins (AFB1, AFB2, AFG1 and AFG2). High reproducibility marked by the low %RSDs of < 1% and low LODs of ≤ 0.02 ng/g were calculated in all cases. The LODs were within the monitoring requirements of the European Commission. The results were validated with a peanut butter certified reference material. The chlorophyll MIP on the other hand selectively removed chlorophyll that would otherwise interfere during pesticide residue analysis (PRA) from > 0.6 to <0.09 Au in green plants extracts. The extracted chlorophyll was removed to far below the level of ≥ 0.399 Au that is usually associated with interference during PRA. Furthermore, the MIP demonstrated better selectivity by removing only chlorophyll (> 99%) in the presence of planar pesticides than the currently employed graphitized carbon black (GCB) that removed both the chlorophyll (> 88%) and planar pesticides (> 89%). For the interfering cholic acid during drug residue analysis, cholic acid MIP electrospun nanofibers demonstrated to be more sensitive and possessing higher loading capacity than the MIP particles. 100% cholic acid was removed by the nanofibers from standard solutions relative to 80% by the particles. This showed that the nanofibers have better performance than the micro particles and as such have potential to replace the particle based SPE sorbents that are currently in use. All the templates were optimally removed from the prepared MIPs by employing a novel pressurized hot water extraction template removal method that was used for the first time in this thesis. The method employed only water, an environmentally friendly solvent to remove templates to ≥ 99.6% with template residual bleeding of ≤ 0.02%.
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- Date Issued: 2012
Creating a space for integrative education within the sciences
- Authors: Van der Post, Leda
- Date: 2012
- Subjects: Computer science -- Vocational guidance , Education, Cooperative , Curriculum evaluation , Experiential learning -- Science
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10482 , http://hdl.handle.net/10948/d1012677 , Computer science -- Vocational guidance , Education, Cooperative , Curriculum evaluation , Experiential learning -- Science
- Description: This thesis documents an action research project that was carried out within the Department of Computing Sciences at the Nelson Mandela Metropolitan University (NMMU), South Africa, from January 2010 to December 2011. The overall aim of the research was to foster an environment in which academics could explore ways to teach using an integrative approach to education. Previous research within the department had raised the concern that students were graduating without the type of high-level cognitive skills that were required in the workplace. While the students’ technical skills were perceived as being excellent, employers indicated that students would benefit from opportunities to develop or improve skills such as communication, teamwork, innovative thinking and time management. These skills include high-level cognitive skills, and are often referred to as “soft skills”. The academics participating in the research project came to believe that it was essential to develop teaching methods that would provide opportunities for students to develop these soft skills, in conjunction with the content and technical knowledge currently addressed in their courses. The research project followed the living theory approach to action research. A living theory action research project allows the researcher to investigate her own teaching, and develop a theory of practice. The theory of practice can be applied to the issues under investigation, to improve the situation or solve problems. At the same time, the theory of practice can contribute to the body of knowledge within the academic domain of the research. Action research is an iterative, cyclical process. There were four research cycles, each one semester in length, during the two years of the project. The project will continue, with a fifth research cycle, starting in January 2012. By the end of the fourth research cycle—Semester Two, 2011—there were eleven academics actively participating in the research group. The project had extended its influence to include academics from the Department of Mathematics at NMMU. The academics ranged from senior, long-serving professors to junior lecturing staff. The results of the research, or the researcher-practitioner’s living theory, explain the process by which an effective and enthusiastic community of practice, dedicated to improving the academics’ teaching and learning practice, was developed. The living theory is applicable to academics within a scientific discipline, desiring to explore and improve their education practice. My living theory explains the characteristics of the TLC (The Learning Community) space, and the action strategies for creating such a space. The explanation of the process of this project includes an analysis of the development process of the research group, typical characteristics of the environment or “space” of the group, and action strategies that other academics could use to create a similar community of practice.
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- Date Issued: 2012
Soil erosion and sediment source dynamics of a catchment in the Eastern Cape province, South Africa: an approach using remote sensing and sediment source fingerprinting techniques
- Authors: Manjoro, Munyaradzi
- Date: 2012
- Subjects: Soil erosion -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10663 , http://hdl.handle.net/10948/d1015038
- Description: This study originated from an evaluation of the performance of a commercially available high concentration point focus concentrator PV system. The effect of module design flaws was studied by using current-voltage (I-V) curves obtained from each module in the array. The position of reverse bias steps revealed the severity of mismatch in a string of series-connected cells. By understanding the effects of the various types of mismatch, power losses and damage to the solar cells resulting from hot spot formation can be minimized and several recommendations for improving the basic performance of similar systems were made. Concern over the extent and type of defect failure of the concentrator photovoltaic (CPV) cells prompted an investigation into the use of a light beam induced current (LBIC) technique to investigate the spatial distribution of defects. An overview of current and developing LBIC techniques revealed that the original standard LBIC techniques have found widespread application, and that far-reaching and important developments of the technique have taken place over the years. These developments are driven by natural progression as well as the availability of newly developed advanced measurement equipment. Several techniques such as Lock-in Thermography and the use of infrared cameras have developed as complementary techniques to advanced LBIC techniques. As an accurate contactless evaluation tool that is able to image spatially distributed defects in cell material, the basis of this method seemed promising for the evaluation of concentrator cells.
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- Date Issued: 2012
Scientific literacy and education for sustainable development: developing scientific literacy in its fundamental and derived senses
- Authors: Leornard, Samantha Lee
- Date: 2012
- Subjects: Science -- Study and teaching , Science -- Experiments
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9450 , http://hdl.handle.net/10948/d1010069 , Science -- Study and teaching , Science -- Experiments
- Description: The importance of developing learners’ scientific literacy in both the fundamental and derived senses has been highlighted by Norris & Phillips (2003). Development of the derived sense of science, which is dependent on the development of a sound fundamental sense of science, aims at promoting scientifically literate societies who are able to make informed decisions concerning the natural environment and the promotion of sustainable livelihoods. In turn, response to increasing recognition of environmental degradation, the United Nations’ Decade of Education for Sustainable Development advocated that the principles, values and practices of sustainable development should be integrated into all aspects of education and learning. However, despite these aspirations, the difficulties of insufficient teacher knowledge and a lack of in-service training, both abroad and within South Africa, remain a challenge. In response to this challenge this study investigated the potential of an Integrated Scientific Literacy Strategy (which aimed at increasing in-service teacher knowledge and skills) to contribute to ESD by developing more scientifically literate teachers and learners in primary education. The study was conducted in 2010 in the Port Elizabeth Metropolitan area in the Eastern Cape, South Africa. The study sample comprised seven schools, with a total of nine teachers and 243 learners participating. As the research is situated within the pragmatic paradigm, a mixed methods approach was followed using Creswell and Plano Clark’s (2007) embedded design’s correlational model whereby quantitative data are rooted within a qualitative design to help verify and explain the outcomes. Qualitative measures were generated through teacher interviews and an analysis of their written portfolios. These data were triangulated against quantitative test data gained from an ANCOVA statistical analysis of the learners’ pre- and post-tests, and both the qualitative and quantitative data gleaned from classroom observations and an analysis of the learners’ science notebooks. The data suggest that, when properly implemented, the Integrated Scientific Literacy Strategy can be used to help teachers develop their learners’ scientific literacy by exposing them to open-ended inquiry investigations. Statistically significant differences (p ≤ 0.01; d=0.88) were noted when comparing improvements in learners’ abilities and understandings of scientific investigations (graphs, variables, inquiry and investigable questions) between those learners whose teachers successfully implemented the strategy in their classrooms, and those learners whose teachers were considered to be ‘non-implementers’ of the strategy. Data from this study also suggest that the successful use of the ISLS enables teachers to integrate issues relating to sustainable development into their natural science lessons. In addition, the learner-orientated approach of the strategy also enabled the learners to engage in autonomous learning environments, aspects of which have been identified as being important for meaningfully learning about and internalising important issues related to ESD.
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- Date Issued: 2012
Studies on existing and new isolates of Cryptophlebia leucotreta granulovirus (CrleGV) on Thaumatotibia leucotreta populations from a range of geographic regions in South Africa
- Authors: Opoku-Debrah, John Kwadwo
- Date: 2012
- Subjects: Cryptophlebia leucotreta Cryptophlebia leucotreta -- South Africa Cryptophlebia leucotreta -- Biological control Cryptophlebia leucotreta -- Life cycles Baculoviruses Lepidoptera -- Biological control Tortricidae -- Biological control Microbial insecticides Pests -- Integrated control
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5778 , http://hdl.handle.net/10962/d1005466
- Description: Baculoviruses are arthropod-specific DNA viruses that are highly virulent to most lepidopteran insects. Their host specificity and compatibility with IPM programmes has enabled their usage as safe microbial insecticides (biopesticides). Two baculovirus-based biopesticides, Cryptogran and Cryptex, which have been formulated with Cryptophlebia leucotreta granulovirus (CrleGV) have been registered for the control of false codling moth (FCM), Thaumatotibia (=Cryptophlebia) leucotreta (Meyrick) (Lepidoptera: Tortricidae) in South Africa and have been successfully incorporated into IPM programmes. However, several studies have indicated that insects can develop resistance to baculovirus-based biopesticide as was shown with field populations of codling moth (CM), Cydia pomonella (L.), which developed resistance to the biopesticide Cydia pomonella granulovirus (CpGV-M) in Europe. Other studies have shown that, under laboratory conditions, FCM populations differ in their susceptibility to Cryptogran and Cryptex. In order to investigate difference in susceptibility as well as protect against any future resistance by FCM to Cryptogran and Cryptex, a search for novel CrleGV-SA isolates from diseased insects from different geographic regions in South Africa was performed. Six geographic populations (Addo, Citrusdal, Marble Hall, Nelspruit, Baths and Mixed colonies) of FCM were established and maintained in the laboratory. Studies on the comparative biological performance based on pupal mass, female fecundity, egg hatch, pupal survival, adult eclosion and duration of life cycle of the Addo, Citrusdal, Marble Hall, Nelspruit and Mixed colonies revealed a low biological performance for the Citrusdal colony. This was attributed to the fact that FCM populations found in the Citrusdal area are not indigenous and may have been introduced from a very limited gene pool from another region. When insects from five colonies, excluding the Baths colony, were subjected to stress by overcrowding , a latent baculovirus resident in the Addo, Nelspruit, Citrusdal, Marble Hall and Mixed colonies was brought into an overt lethal state. Transmission electron micrographs revealed the presence of GV occlusion bodies (OBs) in diseased insects. DNA profiles obtained by single restriction endonuclease analysis of viral genomic DNA using BamH 1, Sa/1, Xba1 , Pst1, Xh01 , Kpn1, Hindlll and EcoR1 revealed five CrleGV-SA isolates latent within the insect populations. The new isolates were named CrleGV-SA Ado, CrleGV-SA Cit, CrleGV-SA Mbl, CrleGVSA Nels and CrleGV-SA Mix isolates. The novelty of the five CrleGV-SA isolates was confirmed by the presence of unique submolar bands, indicating that each isolate was genetically different. PCR amplification and sequencing of the granulin and egt genes from the five isolates revealed several single nucleotide polymorph isms (SNPs) which, in some cases, resulted in amino acid substitutions. DNA profiles from RFLPs, as well as phylogenetic analysis based on granulin and egt sequencing showed the presence of two CrleGV-SA genome types for the CrleGV-SA isolate. Cryptex and CrleGV-SA Ado, CrleGV-SA Cit, CrleGV-SA Mbl and CrleGV-SA Mix were placed as members of Group one CrleGV-SA, and Cryptogran and CrleGV-SA Nels isolate were placed into Group two CrleGV-SA. In droplet feeding bioassays, the median survival time (STso) for neonate larvae inoculated with Group one and two CrleGV-SA were determined to range from 80 - 88 hours (3.33 - 3.67 days), for all five colonies. LDso values for Group one and two CrleGV-SA against neonates from the Addo, Citrusdal, Marble Hall, Nelspruit and Mixed colonies varied between some populations and ranged from 0.80 - 3.12 OBs per larva, indicating some level of variation in host susceptibility. This is the first study reporting the existence of genetically distinct CrleGV baculovirus isolates infecting FCM in different geographical areas of South Africa. The results of this study have broad-ranging implications for our understanding of baculovirus-host interactions and for the application of baculovirus basedbiopesticides.
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- Date Issued: 2012
Identification of novel marine algal compounds with differential anti-cancer activity: towards a cancer stem-cell specific chemotherapy
- Authors: De la Mare, Jo-Anne
- Date: 2012
- Subjects: Breast -- Cancer , Stem cells -- Research , Chemotherapy , Algae -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4143 , http://hdl.handle.net/10962/d1016250
- Description: Breast cancer remains the leading cause of cancer-related death in women worldwide. Furthermore, it has been demonstrated that the treatment-resistant ER-PR-HER2/neu- sub-type is more common among women of African descent, necessitating the search for novel chemotherapies for this form of the disease. The secondary metabolites produced by marine algae represent a rich source of structurally unique compounds with chemotherapeutic potential, particularly in South Africa, whose oceans allegedly host 15 % of the total number of species in the world. Indeed, a recent study reported the isolation of a range of novel compounds from South African red and brown algae of the Plocamium, Portiera and Sargassum genera which displayed cytotoxicity against oesophageal cancer cells in vitro. The molecular mechanisms mediating this toxicity were unknown, as was the effect of these and similar compounds on metastatic ER-PR-HER2/neu- breast cancer cell lines or breast cancer stem cells. The current study aimed to address these questions by screening a library of twenty-two novel marine algal compounds for the ability to inhibit MDA-MB-231 and Hs578T breast cancer cells, while having no adverse effects on non-cancerous MCF12A breast epithelial cells. While twelve of these were toxic in the micromolar range against breast cancer cells, only the polyhalogenated monoterpenes RU004 and RU007, and the tetraprenylated quinone sargaquinoic acid (SQA) were identified as hit compounds based on the criteria that their cytotoxicity was specific to breast cancer and not healthy breast cells in vitro. On the other hand, the halogenated monoterpene RU015 was found to be highly toxic to both breast cancer and non-cancerous breast cell lines, while the halogenated monoterpene stereoisomers RU017 and RU018 were non-toxic to either of these cell lines. The mode of action of RU004, RU007, RU015 and SQA, together with the previously characterized carotenoid fucoxanthin (FXN), was assessed in terms of the type of cell death induced and the effect on cell cycle distribution of these compounds. Flow cytometric analysis of the extent of Hoescht 33342 and propidium iodide staining along with PARP cleavage studies suggested that SQA induced apoptosis in MDA-MB-231 cells. On the other hand, the highly toxic compound RU015 appeared to induce necrosis as evidenced by 50 kDa PARP cleavage product in MDA-MB-231 cells. The flow cytometry profiles of MDA-MB-231 and Hst578T cells treated with the hit compounds RU004 and RU007 were suggestive of the induction of apoptosis by these compounds. Cell cycle analysis by flow cytometry with propidium iodide staining revealed that both SQA and FXN induced G0-G1 arrest together with an increase in the apoptotic sub-G0 population, which agreed with previous reports in the literature. The molecular mechanism of action of SQA and FXN were further investigated by the identification of specific signal transducer molecules involved in mediating their anti-cancer activities. SQA was found to require the activity of numerous caspases, including caspase-3, -6, -8, -9, -10 and -13, for its cytotoxicity and was demonstrated to decrease the level of the antiapoptotic protein Bcl-2. On the other hand, FXN was shown to require caspase-1, -2, -3, -9 and - 10 for its toxicity. This, together with the ability to decrease the levels of Bcl-2, pointed to the involvement of the intrinsic pathway in particular in mediating the activity of FXN. The screening of algal compounds against non-cancerous breast epithelial cells carried out in this study, together with the investigation into their mechanisms of action, represent one of the few reports in which characterization of algal metabolites goes beyond the initial cytotoxicity assays. Finally, in order to assess the potential anti-cancer stem cell activity of the marine algal compounds, a subset of these was screened using a mammosphere assay technique developed in this study. The cancer stem cell (CSC) theory proposes that cancers arise from and are maintained by a specific subpopulation of cells able to undergo asymmetric cell division and termed CSCs. These CSCs are capable of anchorage-independent growth in serum-free culture conditions, such as those in the mammosphere assay. Using this assay, the novel halogenated monoterpene stereoisomers RU017 and RU018 were demonstrated to possess putative anti- CSC activity as evidenced by their ability to completely eliminate mammosphere formation in vitro. Furthermore, since RU017 and RU018 were non-toxic to both breast cancer and healthy breast cells, it appeared that the activity of the compounds was potentially specific to the CSCs. The results require further validation, but represent the first report of selective anti-CSC activity.
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- Date Issued: 2012
Self-perceived professional identity of pharmacy educators
- Authors: Burton, Susan
- Date: 2012
- Subjects: Academic identity , Communities of practice , Identity (Philosophical concept) , Pharmacy -- Study and teaching , Pharmacy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10139 , http://hdl.handle.net/10948/d1008352 , Academic identity , Communities of practice , Identity (Philosophical concept) , Pharmacy -- Study and teaching , Pharmacy
- Description: The philosophy of pharmaceutical care, which defines a patient-centred approach to practice, has been embraced and upheld by national and international pharmaceutical organisations for two decades. However, pharmacists have been slow to change their practice and implement a pharmaceutical care approach. It has been suggested that amongst other factors, short-comings in pharmaceutical education have contributed to this reluctance of the profession to transform practice. Efforts to address these short-comings in pharmaceutical education have focused on the curriculum and pedagogic practices, and not on the pharmacy educators themselves. Palmer (1998) asserts that “good teaching cannot be reduced to technique; good teaching comes from the identity and integrity of the teacher”. In essence, "we teach who we are" and good teachers have one common trait: “a strong sense of personal identity that infuses their work”. This study identified, described and analysed the self-perceived professional identities of pharmacy educators within the South African context. This included ascertaining factors and contexts which contributed to participants’ self-perception of their professional identity. In an effort to understand the influence the educators have on practice and on changing practice and vice-versa, the attitudes, beliefs and behaviours of participants regarding the philosophy and practice of pharmaceutical care, and pharmaceutical education were also explored. Situated within a constructivist-interpretive, qualitative paradigm and making use of methodological triangulation, this study was conducted in three phases, each employing a different qualitative method to collect data. The first phase made use of narrative analysis to gain an in-depth understanding of pharmacy educators’ perceived professional identities and to explore how their experiences, across various contexts, have formed their professional identities. In-depth individual narrative interviews were used to provide a forum in which the participants could reflect upon and tell their professional life-story. This phase of the study also made use of the exploration of metaphors to further investigate the participants’ professional identity and, more particularly, their images of themselves as “teacher” and role model for students. A maximum variation, purposeful sampling approach was used to recruit eight pharmacy academics - one from each school or faculty of pharmacy in South Africa, as participants in this phase of the study. The second and third phases explored more widely, the insights gained from the first phase and the formation of professional identity, attitudes, beliefs and practices of pharmacy educators in South Africa. Two focus groups were employed during the second phase and the study sample was broadened to include a further ten pharmacy educators. In the third phase, a purpose-designed, qualitative questionnaire was used to extend the study sample to all pharmacy educators in South Africa. A convenience sampling approach was used in both the second and third phases of the study. Thematic analysis and interpretation of the narrative interview and focus group transcripts and the questionnaire responses were conducted using qualitative data analysis software – Atlas.ti®. A multiplicity of self-perceived professional identities was described. However, all of these were multi-faceted and could be situated on a continuum between pharmacist identity on one end and academic identity on the other. In addition, six key determinants were recognised as underpinning the participants’ self-perception of their professional identity. These included three structural determinants: expected role; knowledge base; and practice, and three determinants relating to the emotional dimensions and agency of professional identity: professional status; passions; and satisfiers. The professional identity of the participants had been formed through membership of multiple pharmacy-related communities of practice and continued to be sustained through a nexus of multi-membership. There was extensive support by the participants for the concept of pharmaceutical care; however, it did not impact extensively on their role as pharmacy educators. Furthermore, many expressed concern around the use of the term ‘pharmaceutical care’: its definition; its lack of penetration into, and implementation within the practice environment; and even its relevance to the South African healthcare context. Many of the participants perceived the professional development of future pharmacists to be integral to their role as educators, and was often their source of greatest professional satisfaction. However, concern was also expressed at the dissonance that students were perceived to experience, sometimes, because of the incongruities that they are taught and what they experience in practice. This study has afforded pharmacy educators in South Africa an opportunity to understand better “who” they are as professionals, and to reflect on their role as educators and as role models for future pharmacist. Moreover, the findings contribute to a collective understanding of the professional identity of pharmacy educators and socialisation of pharmacy students into the profession. The insights and recommendations emerging from the study have the potential to make academic pharmacy a more attractive career choice which may have positive implications for the future attraction and retention of pharmacists to academic posts within universities.
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- Date Issued: 2012
The past and present limnology of the Soetendalsvlei wetlands, Agulhas coast, South Africa
- Authors: Gordon, Nuette
- Date: 2012
- Subjects: Limnology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10619 , http://hdl.handle.net/10948/d1009430 , Limnology -- South Africa
- Description: As climatic conditions continue to change globally, there is a need to assess past environmental change in relation to changing water balance, temperature and sea-level. By understanding the extent of past environmental change, and how anthropogenic impacts have affected ecosystems, better and more accurate future predictions of change can be made. Through the use of the sedimentary record within coastal wetlands, geochemical, (organic content and stable isotopes) and biological (diatoms) proxies were utilised to determine; (i) the baseline water quality record for Soetendalsvlei, one of only a few coastal lakes in South Africa, (ii) the effect of agriculture and mouth manipulation of the Heuningnes Estuary on the microalgae ecology and (iii) the link between palaeo-salinity and trophic status on a regional basis between Soetendalsvlei and Groenvlei, situated 320 km apart. Present water quality and phytoplankton biomass and community structure were assessed for Soetendalsvlei and its associated wetlands, Voëlvlei and Waskraalsvlei to determine the current health of these systems and to obtain modern diatom analogues to be used in the palaeolimnological reconstruction of the coastal lake. Diatoms were not dominant during this study period. Chlorophytes and flagellates were the dominant phytoplankton groups throughout the different wetlands. With the exception of Voëlvlei, the wetlands were all in good health, although SRP concentrations were within the eutrophic to hypertrophic range and are cause for concern. In Voëlvlei, phytoplankton biomass was within the eutrophic range with chlorophyll a concentrations ranging between 20 – 400 ug.l-1 Cyanobacteria, a further indicator of eutrophic conditions, were dominant during the warmer summer periods. Rainfall and freshwater inflow had a significant effect on the biomass and composition of the phytoplankton and acted as a resetting mechanism for all the wetlands as water quality conditions improved thereafter. Comparisons of the water quality and phytoplankton community between the upper reaches of the Heuningnes Estuary and Soetendalsvlei, indicated that artificial breaching of the estuary mouth significantly impacted the connectivity between these two systems, with marine intrusion extending into the upper reaches, while freshwater conditions dominate in the coastal lake. Unfortunately for the palaeolimnological study diatom preservation was poor, however, geochemistry and stable isotope analyses did provide adequate evidence of marine transgression (~8000 yr BP and 4000-2000 yr BP) and regression events comparable to other South African sea-level models developed for the east and west coast. High organic matter content (i.e. higher trophic state) and estuarine POC (C4 vegetation) were associated with periods of marine regression, i.e. increased freshwater, whereas marine transgression events were associated with low organic content and marine POC and DOC. This is comparable to studies conducted in Uruguay (South America) where palaeo-salinity was related to trophic status, i.e. increased freshwater input was associated with high nutrients. Comparisons of the palaeo-record with recorded historical occurrences of droughts and floods, also provided a means of assessing the sedimentary record and to infer anthropogenic impacts after 1850 AD. Overall it can be concluded that coastal lakes of both continents in the Southern Hemisphere displayed similar trophic responses to sea-level fluctuations during the Holocene. This adds valuable information to global sea-level change models.
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- Date Issued: 2012
The feasibility of monetary integration within the SADC region
- Authors: Nindi, Angelique Gugulethu
- Date: 2012
- Subjects: Southern African Development Community Monetary policy -- Africa, Southern Macroeconomics Africa, Southern -- Economic policy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1021 , http://hdl.handle.net/10962/d1002756
- Description: The Southern African Development Community (SADC) aims to have a regional central bank by 2016 and a common currency by 2018. The member states are at the early stages of the process of regional economic integration, having launched a free trade area in 2008. Monetary integration is an advanced stage of regional economic integration that requires progressive changes in the participating countries. The purpose of this study is to determine the feasibility of monetary integration within the SADC countries and hence, provide policy recommendations to guide the integration process. To accomplish this, the study analyses the extent to which the member states meet the criteria for an optimum currency area (OCA) as well as the degree to which their economies are converging. The study finds that the main macroeconomic objectives of SADC countries differ due to a difference in the relative importance of monetary policy instruments in member states, which influences each country’s commitment towards achieving the macroeconomic convergence targets and harmonising policies. A more appropriate approach to macroeconomic convergence would be to allow for variable speed, geometry and depth in each country as premature adherence to convergence targets could prevent a harmonisation of the economies in the future and possibly destabilise the union. In addition, the study investigates the importance and similarities of the monetary aggregate channel, the interest rate channel, the exchange rate channel and the credit channel in the transmission of monetary policy using VAR analysis. This is important when considering monetary integration because differences in transmission mechanisms can result in asymmetric behaviour between member states, which in turn will prevent harmonisation of their economies. The results of the analysis suggest that SADC member states display asymmetries in their responses to monetary policy shocks as well as the relative importance of transmission mechanisms. In addition, the results suggest that national monetary policy is generally inefficient in determining economic performance in the member states. Furthermore, the study finds that the failure to meet the OCA criteria implies that the SADC member states will respond asymmetrically to shocks within a monetary union. With no effective alternative adjustment mechanisms in place, the effects of the shocks will endure in union members and possibly widen existing cyclical variation. Hence, monetary integration would not result in harmonisation of the economies of member states. It is therefore, concluded that the SADC countries were not suitable for monetary integration at present.
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- Date Issued: 2012