Microbial water quality monitoring of raw and treated water sources in Harare and the effect of gender in disaster management due to water related disasters
- Authors: Chirenda, Tatenda Grace
- Date: 2017
- Subjects: Drinking water Microbiology Zimbabwe Harare , Heterotrophic bacteria Zimbabwe Harare , Emergency management Zimbabwe Harare , Disasters Social aspects Zimbabwe Harare , Water quality management Zimbabwe Harare , Public health Zimbabwe Harare , Sex role Zimbabwe Harare
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/59156 , vital:27444
- Description: Background - Microbial water quality monitoring is essential to the provision of potable water for domestic use. Unsafe water sources increase the risk of waterborne diseases. There is a need to raise awareness of legislature that supports management of water related disasters. Gender, education, health, and economic vulnerability contribute to the success of disaster management. Aim - This study aimed to investigate the microbial water quality of treated water in the Harare area. The study also researched the microbial water quality monitoring practices in Zimbabwe and how these contribute to the management of water borne diseases. The impact of gender, marriage, education, and disease in disaster management practices in Zimbabwe and South Africa was analysed. Method - Literature review was conducted on microbial water quality monitoring practices in Zimbabwe and legislature that supports disaster management. Practices of disaster management in Zimbabwe, and South Africa were investigated and compared. The perspective of the Harare community on the quality of their potable water was investigated through the use of a questionnaire and water quality testing was conducted using hydrogen sulphide test and R2A based heterotrophic plate count. Raw water supplying Manyame River and tap water in Harare households were assessed for microbial quality. Results and Discussion - Raw water sources were found to be contaminated by faecal matter. Household water sources had no faecal contamination, but tested positive for heterotrophic bacteria. The CFU/ml quantities obtained ranged from 1- 452 CFU/ml for all samples. The WHO guidelines for domestic water sources recommend that domestic water should have no coliforms/100 ml sample. Disaster management protocols were available in disaster prone areas such as the Matabeleland South Province. No guidelines were in place for monitoring microbial water quality as a disaster prevention method. Conclusion - The current state of treated water supplied by the Morton Jaffray Treatment Plant was found to be suitable for domestic use, but not sufficient to meet the Harare population’s needs. The need to push for legislature supporting microbial water quality monitoring was recognised. Initiating public / private partnerships in water distribution and water quality monitoring in Zimbabwe was encouraged.
- Full Text:
- Date Issued: 2017
Microencapsulation of anti-tuberculosis drugs using sporopollenin
- Authors: Mhlana, Kanyisile
- Date: 2017
- Subjects: Mycobacterium tuberculosis -- South Africa -- Prevention Microencapsulation , Plant spores
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13912 , vital:27357
- Description: In this thesis, we explore the benefits of microencapsulating isoniazid and pyrazinamide within sporopollenin exine capsules derived from Lycopodium clavatum. Sporopollenin is a natural biopolymer, which is extracted from the outer shell of pollen grains. These hollow microcapsules can encapsulate and release drug actives in a controlled manner and possess many other advantages such as homogeneity in morphology and size, resilience to both strong acids and bases, they have antioxidant properties as well as UV protection to protect the material inside the microcapsule. Compared to artificial microcapsules, sporopollenin’s muco-adhesion to intestinal tissues contributes greatly to the extended contact of the sporopollenin with the intestines leading to an increased efficiency of delivery of drugs. The hollow microcapsules can be easily filled with a solution of the active or active in a liquid form by simply mixing both together. The drug actives are released in the human body depending on pH factors. Active release can otherwise have controlled by adding a coating on the shell, or co-encapsulation with the active inside the shell so that high drug concentrations are delivered to the site of infection. Encapsulation of the drug active will possibly improve therapeutic abilities of the drugs; simplify the treatment of TB-HIV coinfections by eliminating troublesome drug-drug interactions and drastically reduce or eliminates side effects. The SECs were loaded using a passive filling method. The drug active (0.1 g) was dissolved in a solvent and mixed with the SECs (0.1 g) for 10 minutes. After mixing for 10 minutes, the solvent was removed by a rotary evaporator and dried to a constant mass. The surface of the sporopollenin exines were analysed on a FTIR to observe if there are any drug deposits on the surface of the SECs. The loading efficiency and drug release percentage was determined by using calibrations curves and analysed on a UV-vis spectrophotometer. Further work has been proposed in which to characterize the SECs further and producing coated tablets from loaded SECs.
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- Date Issued: 2017
Microstructure and properties of zirconium silicide surface layers on zirlo for improved nuclear fuel cladding
- Authors: Ngongo, Sinoyolo
- Date: 2017
- Subjects: Zirconium alloys Zirconium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/20098 , vital:29107
- Description: Zirconium alloys have important applications as nuclear reactor fuel cladding material. In this study the microstructure and properties of zirconium silicide synthesized by heating ZIRLO (which is an alloy of zirconium and niobium) in contact with silicon powder has been investigated. The silicide acts as a coating layer to protect the ZIRLO from oxidation which is associated with hydrogen pick-up. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate the morphology and crystal structure of the silicides respectively. Heating of ZIRLO with silicon powder was carried out in a Webb 89 Vacuum Furnace for various temperatures (1000–1400 °C) and times (4–8 hours) in an argon atmosphere or under vacuum, which resulted in the diffusion of silicon into the ZIRLO and the formation of zirconium silicide layers. The sample heat treated for 8 hours at 1000 °C did not show any evidence of inter-diffusion between the ZIRLO and silicon, this suggests that a temperature of 1000 °C is not sufficient to facilitate the formation of a silicide layer. The formation of the silicide layer was however observed after heat treatments at 1200 °C and 1400 °C using SEM and TEM. The silicide formed at 1200 °C as a layer on the ZIRLO sample and voids were observed in this layer, most likely due to the Kirkendall effect which occurs in solid state diffusion. The results suggest that Zr has a larger flux than Si as the voids formed in the ZIRLO. The temperature of 1400 °C appears to exceed the ideal required for silicide formation on the surface of ZIRLO, since the silicon infiltrated very far into the ZIRLO and in fact reacted with the entire ZIRLO sample. Both these samples were heat treated for 8 hours in an argon atmosphere. Silicide layers without voids were obtained in the case where ZIRLO and Si were heat treated for 8 and 4 hours at 1200 °C in an argon atmosphere and under vacuum respectively. The average penetration rate, calculated from the aforementioned heat treatments, of Si into Zr was calculated to be 4.5 μm/hour. The diffusion coefficient of Si in Zr was also estimated and it differs by about a factor of 104 from the reported value Zr into Si diffusion coefficient.
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- Date Issued: 2017
Middle management communication in the midst of a crisis
- Authors: Mbolekwano, Veliswa A
- Date: 2017
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/52477 , vital:26194
- Description: Crisis communication by organisational top leadership to external stakeholders has been explored in literature, while internal crisis communication dynamics by middle managers with their employees within the organisation has been under studied. This paper pursues an understanding of crisis communication dynamics between middle management and their subordinates by investigating how the Middle Managers/Team Leaders of Makana Brick Manufacturing Firm (MBMF) communicated with their employees in the midst of the Eskom load shedding crisis in 2014. The investigation is not limited only to how they handled or made sense of the crisis, but also examines the effect and efficiency of their daily communication on both employees (subordinates) and operations in pursuing this end. As a foundation and background, the study broadly explores the literature on Crisis Leadership, Crisis and Crisis Communication, which are critical topics to understanding the communication role of the middle managers who were the primary subject of this research. The research was conducted through semi-structured, face-to-face interviews. Nine Team Leaders were interviewed. The data collected was transcribed verbatim and analysed through open coding. In the literature of crisis management, the concept of crisis communication has been extensively examined as a function of crisis management, primarily with regards to the crisis communication strategy, encompassing the actual verbal and nonverbal responses an organisation uses to address a crisis. The findings are generally congruent with the crisis communication literature, and reinforce the importance of efficient internal communication in building a culture of transparency between management and employees, as espoused in the literature reviewed, which in addition presents an invaluable opportunity for employees across all levels to engage in and be informed of the organisation’s priorities and therefore has the potential to dictate the success or failure of any major change or crisis situation. As such, it can be argued that there is a need for the same analytical rigour that is given to external crisis communication to be given to financial or operational measures (Barrett, 2002). For both external and internal stakeholders, human compassion, concern and empathy; faith in legitimate and appropriate actions taken by the chosen organisation spokesperson; and honesty, candidness and openness in communication (Seeger 2006, p. 242) are universal. The quality and the quantity of communication, essentially, affect the level of trust and involvement of employees (Thomas, Zolin & Hartman, 2009), which is particularly relevant in times of crisis (Mazzei & Ravazzani, 2015 p. 322). Trust must be developed with staff through clear, honest communication and transparent actions. These encompass being fair, open in communication and intentions, showing consistency, fulfilling promises and being honest about what middle managers can and cannot communicate to their employees (Farrel & Schlesinger, 2013, p. 125). In this study, face to face communication proved to be the most preferred communication channel because of its rewarding advantages such as direct feedback, two-way communication, relationship building and project collaboration.
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- Date Issued: 2017
Millennium development goals: lessons from Brazil and Venezuela (2000-2015)
- Authors: Booi, Lusu
- Date: 2017
- Subjects: Brazil -- Economic conditions -- 21st century Venezuela -- Economic conditions -- 21st century , Developing countries -- Economic conditions Sustainable development -- Brazil Sustainable development -- Venezuela Poverty -- Developing countries Economic assistance -- Developing countries -- International cooperation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/14675 , vital:27818
- Description: This research looks at social policy making in Venezuela and Brazil with the objective of alleviating poverty, with special focus on meeting Millennium Development Goals (MDGs) that were set in 2000. Considering the leftist democratic governments that have been established in Latin America since Hugo Chávez was elected president in 1998, and later with Luiz Inacio Lula da Silva in 2002, the research seeks to understand and illustrate what nuances exist in strategy, ideas and implementation of social policy that would positively affect the underprivileged for a more equal and just society. The two countries have deep historical and structural inequalities from slavery, colonialism, imbalanced distribution of resources and like most developing nations of the Global South, have had to endure structural adjustments that have entrenched poverty levels further. Arguments in the past have been made for economic prosperity and economic growth as good indicators for development, however, the research takes a comparative analysis on how Venezuela (through Barrio Adentro and multiple state driven Missions) and Brazil (state supported Bolsa Familia and Universal Health System), have targeted health and education as the primary sectors not just to transform society but also because it is through these sectors that the most effective and efficient manner to measure human development which has thus far been neglected. The research also examines the leadership of the countries which speaks to the differing approaches adopted, style, rhetoric and political realities; and how they have been received not just domestically, but also internationally. The outcomes of the research illustrate a good link between literacy, education and health and a healthy level of state intervention that requires reciprocal social participation for programmes to succeed. Brazil and Venezuela have shown notable creativity and effectiveness in this regard.
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- Date Issued: 2017
Milton Hyland Erickson: psychobiographical study
- Authors: Ramasamy, Kameshnee
- Date: 2017
- Subjects: Erickson, Milton H Psychology -- Biographical methods , Hypnotism -- Therapeutic use
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/14444 , vital:27605
- Description: Historically psychobiography has focused to a large extent on the study of pathology in human development. In recent years, scholars in the field of psychobiography have recommended that studies with a eugraphic focus be undertaken, thereby investigating optimal human development. Milton Hyland Erickson (1901-1980) was an American psychologist and psychiatrist. An extraordinary creative individual who conducted pioneering work in the field of hypnosis. Whilst vast publications of his academic work exist and his work is continued through the Milton H. Erickson Foundation and its global subsidiaries, in comparison, his life story has not been the focus of much study. The psychobiographical merit of Erickson as the subject of the study was based on his involvement in interesting and important events, as well as his resilient attitude towards life, during even dire moments. The focus of this psychobiography was to conceptualise Erickson’s life in terms of the principles of Adler’s Individual Psychology and Peterson and Seligman’s Character Strengths and Virtues Classification. Through this process it was aimed to provide descriptions and interpretations of Erickson’s personality in order to illuminate aspects such as his creativity, service to others, and optimism. The study is written from the first person perspective and is rooted in the interpretive paradigm. It utilises a qualitative research approach in order to gain an in-depth understanding of Erickson’s finished life and thereby taking into account contextual factors. The two theoretical frameworks guided the iterative data collection and data analysis processes and the data were organised into a descriptive framework. The method of data analysis was idiographic thus describing the uniqueness of Erickson life. Strategies such as the triangulation of data sources and theory, focusing on aspects of saliency, trustworthiness, and ethics were employed to ensure reliable data extraction and interpretation. The study revealed that both theoretical frameworks were appropriate in their description and interpretation of Erickson’s personality and character strengths. Of significance was the protective role that creativity, social interest, hope, and optimism played against trauma and these emerged as central themes in Erickson’s life in terms of his psychological wellbeing. The findings on creativity and social interest are supported by existing research and theory but also highlight perspectives for future research. Creativity is a key component of knowledge production and therefore research in this area could improve our understanding of how it can be nurtured and developed across the lifespan. Whilst the construct of social interest was integral to this study its validity in terms of providing adequate explanations of how individuals balance their own needs against the needs of others was examined and suggestions of where the theory can be elaborated were highlighted.
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- Date Issued: 2017
Mineral governance and human development : the case of Western Ghana
- Authors: Danso, Felix
- Date: 2017
- Subjects: Mines and mineral resources -- Ghana Mining law -- Ghana Mineral industries -- Ghana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8725 , vital:33472
- Description: This thesis focuses on mineral governance and how it can contribute to ameliorating human development challenges in Ghana. The study adopted the human centered mineral resource governance approach to assess the mineral governance structure in Ghana and identified that, the current system is a colonial legacy and does not promote human development in Ghana. The study, whilst recognizing the legacies of colonialism, argues that in order for mineral resources to be managed responsibly to promote human development, there should be a paradigm shift to focus on how mineral resources are governed. As a result, the study, relying on the human centered development approach investigates how mineral resources can be governed to promote development in Ghana, with specific focus on the mineral wealth Western Region of the country. Due to the finite nature of mineral resources, the human centered development approach argues that revenues from mineral resources should be invested in human capacity building and medical care delivery. Further, the mining sector should be integrated with other non-mining sectors of the economy to create jobs and provide alternative livelihoods which will go a long way to assist in the general expansion and growth of the country‟s economy. Although this thesis is a case study of mineral governance in Ghana, it can serve as a springboard to appreciate the role mineral governance can play in promoting people centered development in other sub – Saharan mineral wealth countries.
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- Date Issued: 2017
Mineralogical and geochemical constraints on the origin, alteration history and metallogenic significance of the Manganore iron-formation, Northern Cape Province, South Africa
- Authors: Papadopoulos, Vlassis
- Date: 2017
- Subjects: Banded iron formation , Transvaal Supergroup (South Africa) , Groups (Stratigraphy) South Africa , Lithostratigraphy , Petrology South Africa , Geochemistry South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/65189 , vital:28702
- Description: The Manganore iron-formation (MIF) of the Transvaal Supergroup is host to the most important high-grade iron ore bodies in South Africa. Prevailing models for ore genesis invoke supergene processes performing during a long period of erosion, oxidation and weathering under tropical lateritic conditions while the role of potential hydrothermal processes is not addressed. Lack of detailed petrographical and geochemical data necessitated reexamination of the MIF through new and existing drill core exploration material. Thorough petrographical investigation revealed a multi-event complex alteration history involving hydrothermal activity. Iron and silica mobility during alteration is demonstrated by a series of replacement, overprinting, crosscutting textures, extensive silicification and hematitization. Metasomatized textures such as pseudomorphs of primary magnetite, carbonate minerals and chert pods/lenses point to an alteration occurring in layer- controlled fronts and link stratigraphically the MIF to Kuruman and Griquatown iron- formations. Whole-rock geochemical data verify textural observations suggesting strong enrichment of iron or silica in meter-scale horizons, expressed by different generations of quartz and hematite. High-grade iron ore is highly enriched in TiO2 and Al2O3 compared to the protolith while both BIF and iron ore display highly increased concentrations of trace elements (transition metals and HFSE). Oxygen isotopes from different quartz textures reveal little to none isotopic exchangement during alteration whereas O isotopes from hematite are in concert to values from literature and suggest two different generations of hematite. A total of 20 minerals apart from quartz and hematite were documented. An earlier alkali/HFSE alteration event that is believed to have affected the overlying Gamagara shales is recorded in the BIF by the presence of muscovite, apatite, rutile, zircon and xenotime. A later and possibly ongoing event of succeeding hydrothermal pulses involves mainly sulphates (gypsum, baryte, celestine), pyrite, carbonates (siderite, calcite) and silicates (berthierine and tourmaline). Alkali-bearing brines persistently exploit the BIF mainly through karstification-related secondary porosity, are evidently carrying iron and are proposed to participate in or control the iron enrichment by facilitating removal of silica. The source of metals, sulfur and carbon is attributed to the underlying Campbellrand dolomites and especially to the upper Gamogaan Formation. The unconformable contact between BIF and the overlying shales is suggested as a suitable fluid conduit for the development of the observed BIF and shale-derived high-grade hematite iron ore.
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- Date Issued: 2017
Mineralogical variation in the basal Upper Zone, Bushveld Igneous Complex, South Africa: implications for ore genesis and mineral extraction
- Authors: Van Huyssteen, Darryn Ashley
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/5060 , vital:20762
- Full Text:
- Date Issued: 2017
Mineralogy and geochemistry of structurally-controlled metasomatic alteration of carbonate-rich manganese ore at Mamatwan Mine, Kalahari Manganese Field
- Authors: Harawa, Esau Tonderai
- Date: 2017
- Subjects: Metasomatism (Mineralogy) , Manganese ores -- Geology -- South Africa , Geology -- South Africa , Mamatwan Mine (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4717 , vital:20715
- Description: The Kalahari Manganese Field (KMF) located in the Northern Cape Province about 700km south west of Johannesburg contains 80% of the world manganese ore reserves. Mamatwan Mine is hosted within the low grade Mamatwan type ore and is located in the southernmost tip of the KMF. This mine is an open pit mine which is divided into three benches namely the top cut, middle cut and bottom cut. These three benches are structurally controlled by faults which influence the overall grade of the manganese ore. This study is a follow up work to the previous two studies carried out at Wessels Mine and Mamatwan Mine by (Gutzmer and Beukes) in 1995 and 1996 respectively with regards to alteration processes around fault controlled systems in which they concluded that epithermal fluids caused local reduction and bleaching of ore followed by oxidation and carbonate leaching of manganese ore through ascending oxidized groundwater. Metasomatic activity around fault controlled systems is controlled by three main processes namely redistribution, enrichment and depletion. These processes are determined by mobility/immobility of elements from the fault which are introduced into the pre-existing braunite carbonate rich ore. Elements such as Ca, Mg, Si, Fe, C and Mn interact with pre-existing ore due to temperature, fluid pressure, physico-chemical property of fluid gradient. Structurally, faulting and folding contribute to the movement of elements as one end of the system gets depleted the other end of the system gets enriched and vice versa. To better understand this metasomatic activity, it is crucial to conduct mass balance studies of these elements. Grant (1986) introduced the isocon diagram which is a modification of Gresen’s equation (1967) to ascertain which elements are directly or indirectly related to alteration through enrichment and depletion of Ca, Mg, Si, Fe, C and Mn. As the section approaches from altered to less altered manganese ore the mineral chemistry gradually changes from a manganese rich matrix composed of manganomelane and todorokite to a carbonate rich matrix composed of braunite, dolomite, kutnohorite and Mn-rich calcites.
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- Date Issued: 2017
Minimum dietary diversity scores for women indicate micronutrient adequacy and food insecurity status in South African towns
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60930 , vital:27892 , http://dx.doi.org/10.3390/nu9080812
- Description: The lack of dietary diversity is a severe problem experienced by most poor households globally. In particular; women of reproductive age (WRA) are at high risk of inadequate intake of micronutrients resulting from diets dominated by starchy staples. The present study considered the diets, dietary diversity, and food security of women aged 15-49 years along the rural-urban continuum in three South African towns situated along an agro-ecological gradient. A 48 h dietary recall was conducted across two seasons with 554 women from rural, peri-urban, and urban locations of Richards Bay, Dundee, and Harrismith. Minimum Dietary Diversity for WRA (MDD-W) were calculated and a dichotomous indicator based on a set of ten food groups was used to determine if women had consumed at least five food groups the previous 48 h to achieve minimum dietary intake for women. The mean (±sd) MDD-W for Richards Bay (3.78 ± 0.07) was significantly higher than at Dundee (3.21 ± 0.08) and Harrismith (3.36 ± 0.07). Food security and MDD-W were significantly higher in urban locations than in peri-urban or rural ones. There was lower dependence on food purchasing in Richards Bay compared to Dundee and Harrismith. The majority of women in Richards Bay practiced subsistence agriculture, produced a surplus for sale, and collected wild foods which improved dietary intake and food security. The peri-urban populations had limited dietary intake and were more food insecure because of high levels of poverty, unemployment, and lack of land. Peri-urban dwellers are therefore more sensitive to changes in incomes and food prices because they lack safety nets to absorb income or price shocks as they purchase more, rather than growing their own food. This compromises dietary diversity as they have limited access to diverse foods.
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- Date Issued: 2017
Missing values: a closer look
- Authors: Thorpe, Kerri
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/d1017827 , vital:20798
- Description: Problem: In today’s world, missing values are more present than ever. Due to the ever-changing and fast paced global society in which we live, most business and research data produced around the world contain missing data. This means that locating data which is meticulously precise can be a hard task in itself, but at times may prove essential as the consequences of making use of incomplete data could be disastrous. The reasons for missing data cropping up in almost all forms of work are numerous and shall be discussed in this dissertation. For example, those being interviewed or polled may choose to simply ignore questions which are posed to them, recording equipment may malfunction or be misplaced, or organisers may not be able to locate the respondent in order to rectify the missing data. Whatever the reasons for data being incomplete, it is necessary to avoid having to use inefficient and incomplete data as a result from the above problems. Therefore, various strategies or methods have been developed in order to handle these missing values. It is important, however, that these strategies or methods are utilised effectively as missing data treatment can introduce bias into the analysis. This dissertation shall look at these and other problems in more detail by using a data set which consists of records for 581 children who were interviewed in 1990 as part of the National Longitudinal Survey of Youth (NLSY). Approach: As mentioned above, many strategies or methods have been developed in order to deal with missing values. More specifically, traditional methods such as complete case analysis, available case analysis or single imputation are widely used by researchers and shall be discussed herein. Although these methods are simple and easy to implement, they require assumptions about the data that are not often satisfied in practice. Over the years, more up to date and relevant methods, such as multiple imputation and maximum likelihood have been developed. These methods rely on weaker assumptions and contain superior statistical properties when compared to the traditional techniques. In this dissertation, these traditional methods shall be reviewed and assessed in SAS and shall be compared to the more modern techniques. Results: The ad hoc techniques for handling missing data such as complete case and available case methods produce biased parameter estimates when the data is not missing completely at random (MCAR). Single imputation techniques likewise produce biased estimates as well as result in the underestimation of standard errors. Although the expectation maximisation (EM) algorithm yields unbiased parameter estimates, the lack of convenient standard errors suggests that using this algorithm for hypothesis testing is not a good idea. Multiple imputation, however, yields unbiased parameter estimates and correctly estimates standard errors. Conclusion: Ignoring missing data in any analysis produces biased parameter estimates. Using single imputation to handle missing values is not recommended, as using a single value to replace missing values does not account for the variation that would have been present if the variables were observed. As a result, the variance will be greatly underestimated. The more modern missing data methods such as the EM algorithm and multiple imputation are preferred over the traditional techniques as they require less stringent assumptions and they also mitigate the downsides of the older methods.
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- Date Issued: 2017
Modelling dialectical processes in environmental learning
- Authors: Schudel, Ingrid J
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/294409 , vital:57219 , xlink:href="https://doi.org/10.1080/14767430.2017.1288061"
- Description: This paper describes a critical realist intensive case study, which develops and tests a ‘dialectic process model of transformative learning’. The model is inspired by Bhaskar's (1993) onto-axiological chain (or MELD Schema) as outlined in his formulation of dialectical critical realism. The study describes transformative environmental learning processes focusing on food security in two primary schools in rural South Africa. The model elaborates on the four links in the onto-axiological chain by describing four knowledge interests across the two cases: knowledge of ‘what is and what is not’, knowledge of ‘what could be’, knowledge of ‘what should be’, and knowledge of ‘what can be’. The model also highlights the emergent nature of epistemic relations in transformative learning processes. The paper discusses the model in relation to a transformative, open-ended and context specific approach to Environmental Education (EE)/ESD. The paper illustrates that Bhaskar’s MELD is a robust schema for investigating learning-led change in EE and suggests its relevance in other research contexts concerned with societal transformation.
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- Date Issued: 2017
Modelling the causality between FDI and Zimbabwe’s economic growth
- Authors: Mashamhanda, Tendai
- Date: 2017
- Subjects: Investments, Foreign -- Zimbabwe , Zimbabwe -- Economic conditions -- 1965-1980 , Zimbabwe -- Economic conditions -- 1980-
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/50260 , vital:25970
- Description: The study investigates the causal nexus between economic growth and FDI in Zimbabwe for the period spanning 1976 to 2011. The bounds testing approach to cointegration and Granger causality methodology was applied and results suggest a bi-directional causal relationship between FDI and economic growth in the long run. However, the causal effect from economic growth to FDI was weak. Domestic investment, human capital and trade openness were also found to be crucial determinants of economic growth in Zimbabwe. Implementing policies that promote inflow of FDI into Zimbabwe are recommended.
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- Date Issued: 2017
Modelling the effect of graphitization on the fracture toughness (JIC) of service exposed ASTM A-515 Gr. 65 material by the small punch test method
- Authors: Grewar, Stephen James
- Date: 2017
- Subjects: Graphitization Fracture mechanics
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/18849 , vital:28737
- Description: Small Punch Testing is a recent testing methodology with numerous favourable applications in engineering assessments. The advantages of this small specimen method are utilised to derive fracture toughness measurements on service exposed and graphitized steel designated ASTM A-515 Gr. 65. The EPRI-FAA “innovative method”, involving finite element analysis, is applied to obtain fracture toughness estimates and investigate the effect of localised graphitization on localised fracture toughness. The method is described in a stepwise manner and validated favourably against standard fracture toughness testing methods as well as the work of forerunners in this field. Analysis of twenty tested small punch disk specimens extracted from a service exposed welded pipe coupon showed that toughness decreases logarithmically with increased graphitization volumetric percentages in the small samples. Therefore graphitization is found to have a significant influence on local fracture toughness (JIC) of ASTM A-515 Gr. 65 steel under room temperature conditions. The possibility of documenting the effect of microstructural changes on other static properties such as yield strength and strain hardening exists provided that analysis of each disk specimen is performed prior to punch testing. A relationship between percentage graphitization and material toughness has been proposed for ASTM A-515 Gr. 65 at room temperature.
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- Date Issued: 2017
Modelling the intention to change Facebook privacy settings on mobile phones
- Authors: Miya, Asanda Christopher
- Date: 2017
- Subjects: Online social networks -- Security measures Cell phone systems
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/19531 , vital:28890
- Description: Facebook and other social networking services have significantly changed the way people communicate and share information on the Internet. People are increasingly accessing these networking services on mobile phones as opposed to traditional computers. While privacy in social networking services always was a concern, mobile phones make it even easier to share personal information, thus spotlighting privacy concerns. Facebook has privacy settings for the users who use the service on various mobile phones. However, the failure of Facebook users to change privacy settings on mobile phones may result in undesirable sharing of personal information thereby exposing the users to privacy threats. This study extends the understanding of the use of Facebook privacy settings by investigating what impacts the intention to change the privacy settings on mobile phones. The Theory of Planned Behaviour (TPB) is identified as a theoretical underpinning that relates to the intention to perform a behaviour. Structural equation modelling is chosen as a suitable research method. A conceptual model is theorized by building on the Theory of Planned Behaviour. Following suggestions by other studies, the Perceived Behavioural Control (PBC) construct are speci_cally deconstructed into internal and external factors. Nine hypotheses are predicted. A measurement instrument in the form of a questionnaire consisting of 43 items is developed. The conceptual model is evaluated using empirical data, which is gathered from a sample of 414 South African Facebook users. The evaluation of the conceptual model shows it to be a good fit. Out of the nine hypotheses, five are accepted for the final model of the study. Self-efficacy are found to be a positive internal factor that inuences user's perceived control of changing Facebook privacy settings on mobile phones. Facilitating conditions and Perceived Required effort are found to be external factors that respectively have a positive and negative inuence on user's Perceived Behavioural Control. Attitude and Perceived Behavioural Control are both found to have a positive inuence on user's intention to change Facebook privacy settings on mobile phones. The hypotheses that could not be accepted are discussed and it is argued that potential unintended bias in the sample may have had an inuence. More detailed investigation are left for future studies.
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- Date Issued: 2017
Modelling the performance of a calorifier installed at a university residence intended to be retrofited by an air source heat pump
- Authors: Mzolo, Noluthando Precious Duduzile
- Date: 2017
- Subjects: Caloric engines Heat pumps
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4660 , vital:28485
- Description: Sanitary hot water production contributes significantly to the electrical energy consumption in the university campus. An in-depth understanding of the current hot water technology, number of students, capacity of water used per student, time of use of hot water, total volume of hot water consumed and the total energy used on an average weekday in a university residence are very crucial in opting for energy efficient technology like an air source heat pump (ASHP) water heater. The study focused on quantitative and qualitative analysis of data collected for the hot water profiles in one of the university residences (Elitheini 1) from the conduction of experiment and questionnaires. The results revealed that 94% of the 75 students used hot water during the Eskom morning peak and 61% during the Eskom evening peak. In addition, the average daily energy consumption of the 12 kW Calorifier was 139.49 kWh, while the measured volume of hot water usage was 1950 L which is in strong agreement with the total volume (1945 L) of hot water consumption from the questionnaires. The p-value of the average volume of hot water usage measured by experiment and questionnaires was 0.7 and is of no mean significant difference. The monthly energy consumption for the week days was projected to be 2929.31 kWh. By retrofitting of calorifier with an ASHP unit, the energy consumption could reduce to 976.43 kWh based on its consecutive coefficient of performance of 3. Finally, from the energy consumption reduction analysis and the current Eskom tariffs, it can be alluded that the payback period of the proposedASHP unit as a retrofit to the calorifier is going to be less than 2 years and is worthy to invest into such technology under this study due to its favourable payback period and the reliability and lifespan of the ASHP unit.
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- Date Issued: 2017
Modelling water quality : complexity versus simplicity
- Authors: Jacobs, Haden
- Date: 2017
- Subjects: Water quality management -- Mathematical models , Water quality -- Measurement , Water quality biological assessment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4754 , vital:20721
- Description: Water quality management makes use of water quality models as decision making tools. Water quality management decisions need to be informed by information that is as reliable as possible. There are many situations where observational data are limited and therefore models or simulation methods have a significant role to play in providing some information that can be used to guide management decisions. Water quality modelling is the use of mathematical equations and statistics to represent the processes affecting water quality in the natural environment. Water quality data are expensive and difficult to obtain. Nutrient sampling requires a technician to obtain ‘grab samples’ which need to be kept at low temperatures and analysed in a laboratory. The laboratory analyses of nutrients is expensive and time consuming. The data required by water quality models are seldom available as complete datasets of sufficient length. This is especially true for ungauged regions, either in small rural catchments or even major rivers in developing countries. Water quality modelling requires simulated or observed water quantity data as water quality is affected by water quantity. Both the water quality modelling and water quantity modelling require data to simulate the required processes. Data are necessary for both model structure as well as model set up for calibration and validation. This study aimed to investigate the simulation of water quality in a low order stream with limited observed data using a relatively complex as well as a much simpler water quality model, represented by QUAL2K and an in-house developed Mass Balance Nutrient (MBN) model, respectively. The two models differ greatly in the approach adopted for water quality modelling, with QUAL2K being an instream water quality fate model and the MBN model being a catchment scale model that links water quantity and quality. The MBN model uses hydrological routines to simulate those components of the hydrological cycle that are expected to differ with respect to their water quality signatures (low flows, high flows, etc.). Incremental flows are broken down into flow fractions, and nutrient signatures are assigned to fractions to represent catchment nutrient load input. A linear regression linked to an urban runoff model was used to simulate water quality entering the river system from failing municipal infrastructure, which was found to be a highly variable source of nutrients within the system. A simple algal model was adapted from CE-QUAL-W2 to simulate nutrient assimilation by benthic algae. QUAL2K, an instream water quality fate model, proved unsuitable for modelling diffuse sources for a wide range of conditions and was data intensive when compared to the data requirements of the MBN model. QUAL2K did not simulate water quality accurately over a wide range of flow conditions and was found to be more suitable to simulating point sources. The MBN model did not provide accurate results in terms of the simulation of individual daily water quality values; however, the general trends and frequency characteristics of the simulations were satisfactory. Despite some uncertainties, the MBN model remains useful for extending data for catchments with limited observed water quality data. The MBN model was found to be more suitable for South African conditions than QUAL2K, given the data requirements of each model and water quality and flow data available from the Department of Water and Sanitation. The MBN model was found to be particularly useful by providing frequency distributions of water quality loads or concentrations using minimal data that can be related to the risks of exceeding management thresholds.
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- Date Issued: 2017
Modern celebrity and inspiration in South Africa: an examination of the Mail & Guardian 200 Young South Africans
- Authors: Lishivha, Welcome
- Date: 2017
- Subjects: Youth in mass media -- South Africa , Youth -- Social conditions -- South Africa , Mail & Guardian , Mail & Guardian 200 Young South Africans
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/5165 , vital:20782
- Description: The postapartheid condition of a majority of young people in South Africa is substantially similar to the apartheid conditions under which their parents lived. This results in a dominant narrative in the media and everyday talk circulating in South African that the youth are a ‘lost generation’ and also that they represent a significant danger and risk for the stability of our democracy. Against this backdrop The Mail and Guardian, one of the South Africa’s most influential newspapers has chosen to celebrate a small number of young people every year as inspirational and extraordinary in their achievements. This investigation into this representation of a significant - although small - group of young South Africans employed content analysis of the 2015 edition of 200 Young South Africans, interviews with profiled individuals across the years, and a focus group of readers. The study aimed to unpack the complexity of constructing certain young people as exemplary given the structural conditions that constrain and prevent a majority from attaining the education and mobility they need to make a difference in their own lives. The study found through the content analysis that the Mail&Guardian is setting up these young people as exemplary citizens whose actions should inspire other young people to similarly ‘make a difference’. Through the interviews the study found that those featured on the list found both that there was significant social capital in being valorised this way, but that this position was also a complex one to negotiate given the structural limitations of poverty and lack of education for those out of whom they had been chosen. The readers in the focus group did find inspiration in reading about their exemplary peers but they too were conscious of how small a group this was in comparison to the majority of young South Africans. In conclusion the study found that the narrative of hope, inspiration and making a difference is an important message in relation to a generalised hopelessness about South African youth but that it runs the risk of ignoring the significant structural constraints that young, poor, undereducated, unskilled young South Africans face.
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- Date Issued: 2017
Molecular cloning and expression of equine CYP1A2 in Escherichia coli
- Authors: Mkabayi, Lithalethu
- Date: 2017
- Subjects: Escherichia coli , Escherichia coli infections in animals , Cytochrome P-450 , Cytochromes , Horses -- Effect of drugs on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4830 , vital:20734
- Description: Information regarding drug metabolism in veterinary species, especially horses, remains fragmented and incomplete. This information is essential for detection of metabolites of potential performance-enhancing substances in horseracing and for veterinary drug development. Equine liver microsomes have been used to study metabolism of a limited number of drugs, but these provide little information about individual drug metabolizing enzymes. Recombinant CYP enzyme systems are commonly used to determine contribution of individual CYP to metabolism of specific drugs. A limited number of recombinant equine CYPs have been expressed in insect cells and mammalian cell lines. However, there are no reports of recombinant equine CYP1A2 enzyme. In this study, equine CYP1A2 was identified, codon-optimized, cloned and expressed in E. coli BL21 cells. Multiple sequence alignments of equine CYP1A2 revealed an amino acid sequence identity of 83.69% to its human homolog which has previously been expressed in E. coli. The enzyme was expressed using both auto-induction and IPTG induction. Expressed equine CYP1A2 had a size of about 55 kDa, and was insoluble after cell lysis. Sarkosyl- solubilized CYP1A2 was purified using nickel affinity chromatography and gel filtration. For activity reconstitution, yeast NADPH-cytochrome P450 reductase was first expressed in E. coli BL21 cells and exhibited activity of 0.13 U/ml. Activity assay with Glo-P450 CYP1A2 assay kit indicated that CYP1A2 was inactive. Despite numerous attempts to obtain the activity, the CYP1A2 remained inactive. Although expression of equine CYP1A2 in E. coli produced non- catalytically active enzyme, this study could be used as the first step in an effort to fully develop a recombinant equine CYP1A2 system.
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- Date Issued: 2017