Genetic analysis of native and introduced populations of the aquatic weed Sagittaria platyphylla – implications for biological control in Australia and South Africa
- Kwong, Raelene M, Broadhurst, Linda M, Keener, Brian R, Coetzee, Julie A, Knerr, Nunzio, Martin, Grant D
- Authors: Kwong, Raelene M , Broadhurst, Linda M , Keener, Brian R , Coetzee, Julie A , Knerr, Nunzio , Martin, Grant D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76991 , vital:30653 , https://doi.org/10.1016/j.biocontrol.2017.06.002
- Description: Sagittaria platyphylla (Engelm.) J.G. Sm. (Alismataceae) is an emergent aquatic plant native to southern USA. Imported into Australia and South Africa as an ornamental and aquarium plant, the species is now a serious invader of shallow freshwater wetlands, slow-flowing rivers, irrigation channels, drains and along the margins of lakes and reservoirs. As a first step towards initiating a classical biological control program, a population genetic study was conducted to determine the prospects of finding compatible biological control agents and to refine the search for natural enemies to source populations with closest genetic match to Australian and South African genotypes. Using AFLP markers we surveyed genetic diversity and population genetic structure in 26 populations from the USA, 19 from Australia and 7 from South Africa. Interestingly, we have established that populations introduced into South Africa and to a lesser extent Australia have maintained substantial molecular genetic diversity comparable with that in the native range. Results from principal coordinates analysis, population graph theory and Bayesian-based clustering analysis all support the notion that introduced populations in Australia and South Africa were founded by multiple sources from the USA. Furthermore, the divergence of some Australian populations from the USA suggests that intraspecific hybridization between genetically distinct lineages from the native range may have occurred. The implications of these findings in relation to biological control are discussed.
- Full Text:
- Date Issued: 2017
- Authors: Kwong, Raelene M , Broadhurst, Linda M , Keener, Brian R , Coetzee, Julie A , Knerr, Nunzio , Martin, Grant D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76991 , vital:30653 , https://doi.org/10.1016/j.biocontrol.2017.06.002
- Description: Sagittaria platyphylla (Engelm.) J.G. Sm. (Alismataceae) is an emergent aquatic plant native to southern USA. Imported into Australia and South Africa as an ornamental and aquarium plant, the species is now a serious invader of shallow freshwater wetlands, slow-flowing rivers, irrigation channels, drains and along the margins of lakes and reservoirs. As a first step towards initiating a classical biological control program, a population genetic study was conducted to determine the prospects of finding compatible biological control agents and to refine the search for natural enemies to source populations with closest genetic match to Australian and South African genotypes. Using AFLP markers we surveyed genetic diversity and population genetic structure in 26 populations from the USA, 19 from Australia and 7 from South Africa. Interestingly, we have established that populations introduced into South Africa and to a lesser extent Australia have maintained substantial molecular genetic diversity comparable with that in the native range. Results from principal coordinates analysis, population graph theory and Bayesian-based clustering analysis all support the notion that introduced populations in Australia and South Africa were founded by multiple sources from the USA. Furthermore, the divergence of some Australian populations from the USA suggests that intraspecific hybridization between genetically distinct lineages from the native range may have occurred. The implications of these findings in relation to biological control are discussed.
- Full Text:
- Date Issued: 2017
Genetic diversity, evolutionary relationships and conservation of southern African Labeo fishes in relation to water management
- Authors: Ramoejane, Mpho
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5209 , vital:20786
- Description: Labeo spp. are large, herbivorous fishes that are important components of aquatic ecosystems and are a high conservation priority in South Africa. This thesis contributes to determination of conservation priorities for Labeo umbratus (Smith 1841) by resolving the taxonomic status of this species in the evolutionary context of southern African Labeo spp., assessing the presence of unique lineages in historically isolated river basins, and assessing the threat of intra- and interspecific hybridisation associated with introductions. Phylogenetic analyses of five DNA sequence data sets (cytochrome c oxidase subunit I gene [COI], cytochrome b gene [Cyt b], Recombination activating gene 1 [Rag1], COI+Rag1 and COI+Cyt b+Rag1) showed that the Labeo umbratus group (sensu Reid, 1985), which comprises the species Labeo umbratus, Labeo capensis (Smith 1841), Labeo seeberi Gilchrist and Thompson 1911 and Labeo rubromaculatus Gilchrist and Thompson 1913, is monophyletic, morphologically distinct and geographically disjunct from other African Labeo spp. groups except in the Tugela River system were L. rubromaculatus co-occurs with Labeo molybdinus Du Plessis 1963. Phylogeographic analysis of mitochondrial DNA (Cyt b) sequence data demonstrated that the populations of the L. umbratus from the Orange and the southward-flowing river systems are reciprocally monophyletic and were identified as evolutionary significant units. The populations in the southward-flowing river systems were further divided into southwestern (Gourits and Gamtoos) and southeastern (Sundays, Bushmans, Great Fish, Keiskamma, Buffalo and Nahoon) polyp hyletic sublineages. Four management units (Gourits Basin; Gamtoos Basin; Sundays+Bushmans+Great Fish River Basins; and Keiskamma+Buffalo+Nahoon River Basin) were not reciprocally monophyletic but were proposed on the basis of containing unique haplotype frequencies for conservation purposes. To evaluate the threat of hybridisation to the genetic integrity of L. umbratus, the occurrence of Labeo umbratus x L. capensis hybrids was investigated using mtDNA Cyt b and nDNA S7 intron sequence data and morphological data. Genetic evidence for interspecific hybridisation was detected for populations in two impoundments, Hardap Dam (Orange River Basin) and Darlington Dam (Sundays River Basin, Eastern Cape, South Africa). Some putative hybrids were identifiable morphologically on account of intermediacy between the parental species in meristic and morphometric characters. Translocation via direct stocking (Hardap Dam) or via an inter-basin water transfer scheme (Darlington Dam) was identified as a driver for hybridisation. Introductions associated with an inter-basin water transfer scheme has resulted in introgression between the previously isolated Orange River and southern lineages of L. umbratus. Further translocation of fish from these affected areas to non-contaminated river systems and impoundments such as Kat River (Great Fish River) and Slagboom (Sundays River) should be avoided.
- Full Text:
- Date Issued: 2017
- Authors: Ramoejane, Mpho
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5209 , vital:20786
- Description: Labeo spp. are large, herbivorous fishes that are important components of aquatic ecosystems and are a high conservation priority in South Africa. This thesis contributes to determination of conservation priorities for Labeo umbratus (Smith 1841) by resolving the taxonomic status of this species in the evolutionary context of southern African Labeo spp., assessing the presence of unique lineages in historically isolated river basins, and assessing the threat of intra- and interspecific hybridisation associated with introductions. Phylogenetic analyses of five DNA sequence data sets (cytochrome c oxidase subunit I gene [COI], cytochrome b gene [Cyt b], Recombination activating gene 1 [Rag1], COI+Rag1 and COI+Cyt b+Rag1) showed that the Labeo umbratus group (sensu Reid, 1985), which comprises the species Labeo umbratus, Labeo capensis (Smith 1841), Labeo seeberi Gilchrist and Thompson 1911 and Labeo rubromaculatus Gilchrist and Thompson 1913, is monophyletic, morphologically distinct and geographically disjunct from other African Labeo spp. groups except in the Tugela River system were L. rubromaculatus co-occurs with Labeo molybdinus Du Plessis 1963. Phylogeographic analysis of mitochondrial DNA (Cyt b) sequence data demonstrated that the populations of the L. umbratus from the Orange and the southward-flowing river systems are reciprocally monophyletic and were identified as evolutionary significant units. The populations in the southward-flowing river systems were further divided into southwestern (Gourits and Gamtoos) and southeastern (Sundays, Bushmans, Great Fish, Keiskamma, Buffalo and Nahoon) polyp hyletic sublineages. Four management units (Gourits Basin; Gamtoos Basin; Sundays+Bushmans+Great Fish River Basins; and Keiskamma+Buffalo+Nahoon River Basin) were not reciprocally monophyletic but were proposed on the basis of containing unique haplotype frequencies for conservation purposes. To evaluate the threat of hybridisation to the genetic integrity of L. umbratus, the occurrence of Labeo umbratus x L. capensis hybrids was investigated using mtDNA Cyt b and nDNA S7 intron sequence data and morphological data. Genetic evidence for interspecific hybridisation was detected for populations in two impoundments, Hardap Dam (Orange River Basin) and Darlington Dam (Sundays River Basin, Eastern Cape, South Africa). Some putative hybrids were identifiable morphologically on account of intermediacy between the parental species in meristic and morphometric characters. Translocation via direct stocking (Hardap Dam) or via an inter-basin water transfer scheme (Darlington Dam) was identified as a driver for hybridisation. Introductions associated with an inter-basin water transfer scheme has resulted in introgression between the previously isolated Orange River and southern lineages of L. umbratus. Further translocation of fish from these affected areas to non-contaminated river systems and impoundments such as Kat River (Great Fish River) and Slagboom (Sundays River) should be avoided.
- Full Text:
- Date Issued: 2017
Genetic matching of invasive populations of the African tulip tree, Spathodea campanulata Beauv.(Bignoniaceae), to their native distribution: Maximising the likelihood of selecting host-compatible biological control agents
- Sutton, Guy F, Paterson, Iain D, Paynter, Quentin
- Authors: Sutton, Guy F , Paterson, Iain D , Paynter, Quentin
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405797 , vital:70207 , xlink:href="https://doi.org/10.1016/j.biocontrol.2017.08.015"
- Description: Spathodea campanulata Beauv (Bignoniaceae) has become a highly damaging environmental and agricultural weed in the Pacific Islands. It has been targeted for biological control due to the costly and inefficient nature of physical and chemical control methods. Determining the origin of weed populations has been increasingly recognised as an important component of successful biological control programmes, and may be important for the biological control of S. campanulata due to the high degree of morphological variability within the species, as well as the broad native distribution. Genetic matching, using inter-simple sequence repeats (ISSR’s), and morphological data found support for invasive Pacific Island S. campanulata plants originating from West Africa. Pacific and West African plants were genetically most similar, and were differentiated from native plants from East/Central Africa by PCA and Bayesian-clustering (STRUCTURE) analyses. Genetic data was corroborated by morphological data which showed that West African and Pacific Islands plants had more sparsely pubescent leaves compared to plants from East/Central Africa. Populations in South Africa, where the plant is introduced but not problematic, originated from a different source population than those in the Pacific Islands, probably in East/Central Africa. A greater sampling effort is required before the origin of the South African populations can be determined with certainty. Herbivores and pathogens for the Pacific Islands should be collected from West Africa as they are more likely to be compatible with S. campanulata plants in this region.
- Full Text:
- Date Issued: 2017
- Authors: Sutton, Guy F , Paterson, Iain D , Paynter, Quentin
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405797 , vital:70207 , xlink:href="https://doi.org/10.1016/j.biocontrol.2017.08.015"
- Description: Spathodea campanulata Beauv (Bignoniaceae) has become a highly damaging environmental and agricultural weed in the Pacific Islands. It has been targeted for biological control due to the costly and inefficient nature of physical and chemical control methods. Determining the origin of weed populations has been increasingly recognised as an important component of successful biological control programmes, and may be important for the biological control of S. campanulata due to the high degree of morphological variability within the species, as well as the broad native distribution. Genetic matching, using inter-simple sequence repeats (ISSR’s), and morphological data found support for invasive Pacific Island S. campanulata plants originating from West Africa. Pacific and West African plants were genetically most similar, and were differentiated from native plants from East/Central Africa by PCA and Bayesian-clustering (STRUCTURE) analyses. Genetic data was corroborated by morphological data which showed that West African and Pacific Islands plants had more sparsely pubescent leaves compared to plants from East/Central Africa. Populations in South Africa, where the plant is introduced but not problematic, originated from a different source population than those in the Pacific Islands, probably in East/Central Africa. A greater sampling effort is required before the origin of the South African populations can be determined with certainty. Herbivores and pathogens for the Pacific Islands should be collected from West Africa as they are more likely to be compatible with S. campanulata plants in this region.
- Full Text:
- Date Issued: 2017
Genetically modified (GM) maize cultivation by smallholders in the Eastern Cape Province of South Africa: Effects on target and non-target organisms and adoption challenges
- Authors: Kotey, Daniel Ashie
- Date: 2017
- Subjects: Farms, Small -- South Africa -- Eastern Cape Genetically modified foods -- South Africa -- Eastern Cape Corn -- Biotechnology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5161 , vital:29092
- Description: The use of genetically modified (GM) maize technology is subject to compliance with stewardship requirements and the adoption of specific management practices that promote the long-term effectiveness and environmental sustainability of the technology. For smallholders to comply with these requirements and adopt the desired management practices to ultimately benefit from the technology, they require information that creates awareness of the value of these requirements. To determine what information farmers receive about GM maize and how this information is disseminated to farmers, face to face interviews were conducted with 81 extension personnel and 210 smallhoder GM maize farmers in the Eastern Cape Province of South Africa. The effect of Bt maize introduction and management practices in smallholder maize agroecosystems in the Eastern Cape on Bt maize target [Busseola fusca (Fuller) (Lepidoptera: Noctuidae)] and non-target insect pests [Agrotis segetum (Denis & Schiffermüller) (Lepidoptera: Noctuidae), Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)] and a snail species, [Cornu aspersum (Müller) (Gastropoda: Helicidae)] was determined through laboratory, field and cage experiments. The effect of smallhoder farmers‟ GM maize cultivation practices on the profitability of GM maize technology was also determined through on-farm trials in different localities of the Eastern Cape identified as hot-spots for stem borer and weed infestation. Results of surveys indicated that extension personnel had a low level of awareness of GM maize technology stewardship requirements. GM maize technology was also largely disseminated to smallholder farmers through non-participatory approaches and print media sourced from GM seed companies. Although farmers had a high level of contact with extension services, they lacked access to information about GM maize technology. Smallholder farmers‟ level of awareness about GM maize and compliance with the requirement for the planting of non-Bt maize refuge areas adjacent to Bt maize was also very low. While Bt maize event (MON810) commonly cultivated by smallholder farmers in the Eastern Cape Province had a variable effect on A. segetum under laboratory conditions, it had no effect on the incidence of plants damaged by A. segetum and C. aspersum under field conditions. The incidence of H. armigera damage on Bt maize plants was however significantly affected by Bt maize. Populations of B. fusca collected from smallholder maize fields in the province were observed to be still highly susceptible to Bt maize. Results of on-farm evaluation of the profitability of GM maize revealed that stem borer pressure, growing conditions, input supplies and market access affect the productivity and profitability of GM maize cultivation. Challenges within the extension and advisory services of the Eastern Cape which can militate against smallholder farmers‟ ability to benefit from GM maize technology and sustain the long-term efficacy of the technology were identified during this study. Given these challenges and the fact that the cultivation of GM maize may not be profitable under typical smallholder maize cultivation conditions and management practices, dissemination approaches that provide farmers the opportunity to evaluate GM maize technology alongside alternate technologies under their conditions, may prove beneficial.
- Full Text:
- Date Issued: 2017
- Authors: Kotey, Daniel Ashie
- Date: 2017
- Subjects: Farms, Small -- South Africa -- Eastern Cape Genetically modified foods -- South Africa -- Eastern Cape Corn -- Biotechnology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5161 , vital:29092
- Description: The use of genetically modified (GM) maize technology is subject to compliance with stewardship requirements and the adoption of specific management practices that promote the long-term effectiveness and environmental sustainability of the technology. For smallholders to comply with these requirements and adopt the desired management practices to ultimately benefit from the technology, they require information that creates awareness of the value of these requirements. To determine what information farmers receive about GM maize and how this information is disseminated to farmers, face to face interviews were conducted with 81 extension personnel and 210 smallhoder GM maize farmers in the Eastern Cape Province of South Africa. The effect of Bt maize introduction and management practices in smallholder maize agroecosystems in the Eastern Cape on Bt maize target [Busseola fusca (Fuller) (Lepidoptera: Noctuidae)] and non-target insect pests [Agrotis segetum (Denis & Schiffermüller) (Lepidoptera: Noctuidae), Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)] and a snail species, [Cornu aspersum (Müller) (Gastropoda: Helicidae)] was determined through laboratory, field and cage experiments. The effect of smallhoder farmers‟ GM maize cultivation practices on the profitability of GM maize technology was also determined through on-farm trials in different localities of the Eastern Cape identified as hot-spots for stem borer and weed infestation. Results of surveys indicated that extension personnel had a low level of awareness of GM maize technology stewardship requirements. GM maize technology was also largely disseminated to smallholder farmers through non-participatory approaches and print media sourced from GM seed companies. Although farmers had a high level of contact with extension services, they lacked access to information about GM maize technology. Smallholder farmers‟ level of awareness about GM maize and compliance with the requirement for the planting of non-Bt maize refuge areas adjacent to Bt maize was also very low. While Bt maize event (MON810) commonly cultivated by smallholder farmers in the Eastern Cape Province had a variable effect on A. segetum under laboratory conditions, it had no effect on the incidence of plants damaged by A. segetum and C. aspersum under field conditions. The incidence of H. armigera damage on Bt maize plants was however significantly affected by Bt maize. Populations of B. fusca collected from smallholder maize fields in the province were observed to be still highly susceptible to Bt maize. Results of on-farm evaluation of the profitability of GM maize revealed that stem borer pressure, growing conditions, input supplies and market access affect the productivity and profitability of GM maize cultivation. Challenges within the extension and advisory services of the Eastern Cape which can militate against smallholder farmers‟ ability to benefit from GM maize technology and sustain the long-term efficacy of the technology were identified during this study. Given these challenges and the fact that the cultivation of GM maize may not be profitable under typical smallholder maize cultivation conditions and management practices, dissemination approaches that provide farmers the opportunity to evaluate GM maize technology alongside alternate technologies under their conditions, may prove beneficial.
- Full Text:
- Date Issued: 2017
Geological and geophysical investigations of the reservoir rock properties of the Gamtoos Basin in the Eastern Cape Province of South Africa
- Mokoele, Salmina Phuti 0000-0001-8096-8350
- Authors: Mokoele, Salmina Phuti 0000-0001-8096-8350
- Date: 2017
- Subjects: Petroleum reserves -- Mechanical properties Petroleum reserves -- South Africa -- Eastern Cape Geophysics -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7863 , vital:30779
- Description: Geological and geophysical studies of the Gamtoos Basin were carried out by using the research methods of stratigraphic analysis, petrographic analysis, sedimentary facies analysis, and geophysical studies. The orientation of the Gamtoos Basin onshore is controlled by the Gamtoos Fault which cuts through the lithologies of the Cape Supergroup on the eastern edge of the basin. Magnetic data and depth slices show the presence of the Cape Supergroup basement on the south east corner of the onshore Kirkwood Formation which is further sitting on the Gamtoos Group basement from the Neoproterozoic extending up to 8860 m in depth. Most previously compiled stratigraphic profiles of the Uitanhage Group revealed the presence of reddish massive conglomerate units from the Enon Formation and massive reddish to greenish alternating units of sandstones, siltstones and mudstones from the Kirkwood Formation. The results obtained from this research also revealed the presence of reddish to whitish massive alternating units of sandstones, mudstones and siltstones from the upper Enon Formation overlaying the reddish massive conglomeritic layers while the alternating reddish to greenish units of sandstones, siltstones and mudstones from the Kirkwood Formation are overlaid by massive reddish to greyish conglomeritic layers. Thirteen types of lithofacies and five types of biofacies were accounted for across the Gamtoos Basin from core logs, field observations and petrographic analysis. The same type of reddish to greyish massive conglomerate facies interbedded with subordinate sandstone lenses were observed on both the Enon (Lower most part) and the Kirkwood (top most part) Formations. Similar reddish to whitish sandstone facies were also observed in both formations except some of the units from the Kirkwood Formation revealed the presence of a lot of sedimentary structures such as laminations, thin beds, tabular cross beds, trough cross beds, convolute structures, load casts and even secondary structures like calcite veins and honey comb structures. Mudstone deposits are divided into reddish laminated facies and whitish massive facies. The whitish mudstone facies of the Enon Formation comprise caliche indicating the process of leaching while the reddish facies contain mudcracks indicating the process of desiccation. The Kirkwood Formation comprises reddish laminated mudstone facies and whitish massive mudstones. Petrographic studies revealed the presence of quartz arenites, lithic arenites, quartz wacke, lithic wacke, pelletic wacke, siltstones and mudstones. The mineral compositions were monocrystalline and polycrystalline quartz, plagioclase, K-feldspar and lithic fragments as the main framework grains. Muscovite and glauconite were identified as accessory minerals along with heavy minerals of hematite spotted on a few occasions. The matrix was composed of clay (mainly kaolinite and smectite), bentonite, illite-sericite and fine quartz silts. Microscope petrography revealed that organic matters occurred in 4 occurrences, i.e. as organic intraclasts, kerogen pellets, organic carbon laminae or stringers, and diagenetic crack-filling organic carbon (asphalt). Density determinations onshore have revealed an average wet density of 2.439 g/cm3 for the Enon Formation sandstones and 2.589 g/cm3 for the Kirkwood Formation sandstones. The average rock density for Borehole Ha-B2 is 2.67 g/cm3 whereas Borehole Ha-G1 rocks show an average density of 2.64 g/cm3. Geophysical data from the offshore boreholes has indicated an increase in the following parameters with depth: bulk density, porosity and geothermal gradient. Data from borehole logs resulted in a linear relationship between bulk density and depth although some boreholes were represented by more than one linear segment in one graph still showing gradual increase of bulk density with depth. The basin was deposited in terrestrial environments (braided fluvial fans and meandering rivers) and marine environments (beach, shallow and deep marine).
- Full Text:
- Date Issued: 2017
- Authors: Mokoele, Salmina Phuti 0000-0001-8096-8350
- Date: 2017
- Subjects: Petroleum reserves -- Mechanical properties Petroleum reserves -- South Africa -- Eastern Cape Geophysics -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7863 , vital:30779
- Description: Geological and geophysical studies of the Gamtoos Basin were carried out by using the research methods of stratigraphic analysis, petrographic analysis, sedimentary facies analysis, and geophysical studies. The orientation of the Gamtoos Basin onshore is controlled by the Gamtoos Fault which cuts through the lithologies of the Cape Supergroup on the eastern edge of the basin. Magnetic data and depth slices show the presence of the Cape Supergroup basement on the south east corner of the onshore Kirkwood Formation which is further sitting on the Gamtoos Group basement from the Neoproterozoic extending up to 8860 m in depth. Most previously compiled stratigraphic profiles of the Uitanhage Group revealed the presence of reddish massive conglomerate units from the Enon Formation and massive reddish to greenish alternating units of sandstones, siltstones and mudstones from the Kirkwood Formation. The results obtained from this research also revealed the presence of reddish to whitish massive alternating units of sandstones, mudstones and siltstones from the upper Enon Formation overlaying the reddish massive conglomeritic layers while the alternating reddish to greenish units of sandstones, siltstones and mudstones from the Kirkwood Formation are overlaid by massive reddish to greyish conglomeritic layers. Thirteen types of lithofacies and five types of biofacies were accounted for across the Gamtoos Basin from core logs, field observations and petrographic analysis. The same type of reddish to greyish massive conglomerate facies interbedded with subordinate sandstone lenses were observed on both the Enon (Lower most part) and the Kirkwood (top most part) Formations. Similar reddish to whitish sandstone facies were also observed in both formations except some of the units from the Kirkwood Formation revealed the presence of a lot of sedimentary structures such as laminations, thin beds, tabular cross beds, trough cross beds, convolute structures, load casts and even secondary structures like calcite veins and honey comb structures. Mudstone deposits are divided into reddish laminated facies and whitish massive facies. The whitish mudstone facies of the Enon Formation comprise caliche indicating the process of leaching while the reddish facies contain mudcracks indicating the process of desiccation. The Kirkwood Formation comprises reddish laminated mudstone facies and whitish massive mudstones. Petrographic studies revealed the presence of quartz arenites, lithic arenites, quartz wacke, lithic wacke, pelletic wacke, siltstones and mudstones. The mineral compositions were monocrystalline and polycrystalline quartz, plagioclase, K-feldspar and lithic fragments as the main framework grains. Muscovite and glauconite were identified as accessory minerals along with heavy minerals of hematite spotted on a few occasions. The matrix was composed of clay (mainly kaolinite and smectite), bentonite, illite-sericite and fine quartz silts. Microscope petrography revealed that organic matters occurred in 4 occurrences, i.e. as organic intraclasts, kerogen pellets, organic carbon laminae or stringers, and diagenetic crack-filling organic carbon (asphalt). Density determinations onshore have revealed an average wet density of 2.439 g/cm3 for the Enon Formation sandstones and 2.589 g/cm3 for the Kirkwood Formation sandstones. The average rock density for Borehole Ha-B2 is 2.67 g/cm3 whereas Borehole Ha-G1 rocks show an average density of 2.64 g/cm3. Geophysical data from the offshore boreholes has indicated an increase in the following parameters with depth: bulk density, porosity and geothermal gradient. Data from borehole logs resulted in a linear relationship between bulk density and depth although some boreholes were represented by more than one linear segment in one graph still showing gradual increase of bulk density with depth. The basin was deposited in terrestrial environments (braided fluvial fans and meandering rivers) and marine environments (beach, shallow and deep marine).
- Full Text:
- Date Issued: 2017
Geological study and economic evaluation of the Paardeplaats Coal Exploration Project
- Authors: Gcayi, Gcobani
- Date: 2017
- Subjects: Coal Geology South Africa Mpumalanga , Coal Prospecting South Africa Mpumalanga , Coal mines and mining South Africa Mpumalanga , Geology, Economic South Africa , Coal reserves South Africa Mpumalanga
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59183 , vital:27452
- Description: For a coal mining company the coal resources are an important asset, and they are acquired in a number of different ways, such as obtaining a prospecting permit from government or an existing permit from another entity and or purchasing an operating colliery from another entity. The Paardeplaats Project is a brownfields project located approximately 7 km south west of the town of Belfast in Mpumalanga Province, South Africa, on the far eastern edge of the Witbank Coalfield. The project is located adjacent to an operating mine, Glisa Colliery, owned by Eyesizwe Coal. Eyesizwe Coal was awarded the prospecting permit in 2006 by the Department of Mineral Resources. Subsequent exploration activities, which included airborne magnetic survey and borehole drilling, were conducted between 2008 and 2010. The results of the drilling confirmed the presence of coal resources, which are classified in the Measured, Indicated and Inferred categories. Mining and beneficiation methods from the adjacent Glisa Colliery, which has similar geology to the project area, were assumed in order to generate a coal reserve statement. The Coal Reserve qualities are suitable to the domestic market, particularly Eskom. South Africa’s coal supply is demand driven, primarily from Eskom for electricity generation followed by the export market and thirdly by Sasol for synthetic fuel generation. The majority of Eskom’s existing coal-fired power stations are located in the Mpumalanga Province, which provides a viable market for coal projects in Mpumalanga when considering existing transport infrastructure and transportation costs. Eskom’s continued demand for coal in the Mpumalanga region, at least until 2040, provides a future market for advanced coal projects in the region. A valuation of the project using the Cash Flow Approach showed the project to be economically viable. , Thesis (MSc) -- Faculty of Faculty of Science, Geology, 2017
- Full Text:
- Date Issued: 2017
- Authors: Gcayi, Gcobani
- Date: 2017
- Subjects: Coal Geology South Africa Mpumalanga , Coal Prospecting South Africa Mpumalanga , Coal mines and mining South Africa Mpumalanga , Geology, Economic South Africa , Coal reserves South Africa Mpumalanga
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59183 , vital:27452
- Description: For a coal mining company the coal resources are an important asset, and they are acquired in a number of different ways, such as obtaining a prospecting permit from government or an existing permit from another entity and or purchasing an operating colliery from another entity. The Paardeplaats Project is a brownfields project located approximately 7 km south west of the town of Belfast in Mpumalanga Province, South Africa, on the far eastern edge of the Witbank Coalfield. The project is located adjacent to an operating mine, Glisa Colliery, owned by Eyesizwe Coal. Eyesizwe Coal was awarded the prospecting permit in 2006 by the Department of Mineral Resources. Subsequent exploration activities, which included airborne magnetic survey and borehole drilling, were conducted between 2008 and 2010. The results of the drilling confirmed the presence of coal resources, which are classified in the Measured, Indicated and Inferred categories. Mining and beneficiation methods from the adjacent Glisa Colliery, which has similar geology to the project area, were assumed in order to generate a coal reserve statement. The Coal Reserve qualities are suitable to the domestic market, particularly Eskom. South Africa’s coal supply is demand driven, primarily from Eskom for electricity generation followed by the export market and thirdly by Sasol for synthetic fuel generation. The majority of Eskom’s existing coal-fired power stations are located in the Mpumalanga Province, which provides a viable market for coal projects in Mpumalanga when considering existing transport infrastructure and transportation costs. Eskom’s continued demand for coal in the Mpumalanga region, at least until 2040, provides a future market for advanced coal projects in the region. A valuation of the project using the Cash Flow Approach showed the project to be economically viable. , Thesis (MSc) -- Faculty of Faculty of Science, Geology, 2017
- Full Text:
- Date Issued: 2017
Geomorphological connectivity and sensitivity examined in a recently degraded gravel-bed stream: implications for river-floodplain rehabilitation
- Authors: Powell, Rebecca
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/53722 , vital:26313
- Description: The study of river complexity and sensitivity to future human land-use activities and climate change is a fast growing field within the discipline of fluvial geomorphology. Associated with this is a need to improve river rehabilitation and catchment management approach, design and effectiveness. This study aimed to investigate drivers of the recent geomorphological sensitivity of the Baviaanskloof River-floodplain, an upland system in South Africa, by integrating the concepts of geomorphological connectivity and Panarchy. The understanding generated was used to evaluate the approach of the State agency, Working for Wetlands (WfWet), to river-floodplain rehabilitation in the catchment.The concepts of geomorphological connectivity and Panarchy provide useful frameworks for understanding interactions between geomorphological processes and structure across scales of space and time. Geomorphological connectivity explains the degree to which water and sediment is linked in a river landscape, determined by the distribution of erosional and depositional landforms (Brierley et al. 2006; Fryirs et al. 2007a; Fryirs et al. 2007b). Panarchy attempts to explain lagged response to disturbances, non-linear interactions, and sudden shifts in system state, and has been applied largely to ecological systems. Panarchy theory, when combined with the concept of geomorphological connectivity, provides a guiding framework for understanding river complexity in greater depth. The first results chapter of this study investigated river long-term and recent geomorphological history, towards understanding the nature and timing of river geomorphological cycling between erosion and deposition. Optically Stimulated Luminescence dating of alluvial fan and floodplain sedimentary units was conducted, for analysis of river-floodplain long-term history (100s to 1 000s of years). Interviews with 11 local landowners, combined with analysis of historic aerial imagery and river-floodplain topographic surveys, provided a means of describing recent (last few decades) geomorphological dynamics. The results indicated that the Baviaanskloof is naturally a cut- and-fill landscape over scales of several hundred to thousands of years, characterized by the alternation between phases of high fluvial energy and alluvial fan expansion, and low energy conditions associated with floodplain accretion. Recent and widespread river-floodplain degradation was compressed into a short period of approximately 30 years, suggesting that one or more drivers have pushed the system beyond a threshold, resulting in increased water and sediment connectivity. The second results chapter investigated the role of human land-use activities and flooding frequency and magnitude, as drivers of recent river-floodplain degradation. Human impacts were investigated by describing land-use activities for the preceding 80 years, and relating these activities to changes in river-floodplain form and behavior. Temporal trends in flood events of different frequency and magnitude were investigated by analyzing rainfall data, integrated with landowner reports of flood-inducing rainfall magnitudes. The findings indicated that human land-use activities have been an important driver of recent river- floodplain degradation, through the enhancement of water and sediment connectivity across spatial scales of the catchment. Episodic and high magnitude floods synergized with human driven increased connectivity, precipitating stream power and geomorphological threshold breaches, resulting in a shift in river behaviour. The third results chapter investigated the influence of tributary-junction streams and fans on the geomorphological form, behavior and sensitivity of the Baviaanskloof River. Local- scale topographic impacts of tributary fans and streams were described using topographic surveys and geomorphological mapping techniques. Tributary streams form a major control on the behaviour of the river, by influencing the degree of coarse sediment connectivity with the main channel. Although tributary fans buffer the river from disturbances occurring in the wider catchment, they initiate topographic variations along the floodplain, influencing local-scale patterns of deposition and erosion along the river. The main river responds to water and sediment inputs from tributary junction streams by locally adjusting longitudinal slope, maintaining an overall constant slope of 0.0066 m/m. The response of the Baviaanskloof River to tributary junction fans and streams is however variable, and is fashioned by complex interactions between geomorphological and anthropogenic factors. The final two chapters of the thesis evaluate the findings of the study within the context of river-floodplain rehabilitation approaches in South Africa, and within the theoretical, philosophical and methodological context of the research. The first of these two chapters evaluates the approach of the WfWet programme to river-floodplain rehabilitation in the Baviaanskloof. The chapter indicates that the present practice of WfWet is to reinstate a pre-degradation state, which is not suited to the Baviaanskloof River-floodplain, since the river-floodplain has passed a geomorphological threshold, resulting in a new set of interacting processes and landforms. The author presents a conceptual model illustrating the existence of geomorphological adaptive cycles interacting across spatial and temporal scales, thereby attempting to explain a river Panarchy specific to the Baviaanskloof. From this conceptual model, a hierarchical rehabilitation framework, targeting geomorphological processes and structure situated at different spatial and temporal scales of the landscape is suggested. The final chapter discusses the implications of integrating the concepts of geomorphological connectivity and river Panarchy theory in studies of river complexity and sensitivity to geomorphological change. The author suggests that there is scope for further investigation of the application of the two concepts within the discipline of fluvial geomorphology, particularly with regard to developing quantitative approaches to measuring and describing connectivity and Panarchy.
- Full Text:
- Date Issued: 2017
- Authors: Powell, Rebecca
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/53722 , vital:26313
- Description: The study of river complexity and sensitivity to future human land-use activities and climate change is a fast growing field within the discipline of fluvial geomorphology. Associated with this is a need to improve river rehabilitation and catchment management approach, design and effectiveness. This study aimed to investigate drivers of the recent geomorphological sensitivity of the Baviaanskloof River-floodplain, an upland system in South Africa, by integrating the concepts of geomorphological connectivity and Panarchy. The understanding generated was used to evaluate the approach of the State agency, Working for Wetlands (WfWet), to river-floodplain rehabilitation in the catchment.The concepts of geomorphological connectivity and Panarchy provide useful frameworks for understanding interactions between geomorphological processes and structure across scales of space and time. Geomorphological connectivity explains the degree to which water and sediment is linked in a river landscape, determined by the distribution of erosional and depositional landforms (Brierley et al. 2006; Fryirs et al. 2007a; Fryirs et al. 2007b). Panarchy attempts to explain lagged response to disturbances, non-linear interactions, and sudden shifts in system state, and has been applied largely to ecological systems. Panarchy theory, when combined with the concept of geomorphological connectivity, provides a guiding framework for understanding river complexity in greater depth. The first results chapter of this study investigated river long-term and recent geomorphological history, towards understanding the nature and timing of river geomorphological cycling between erosion and deposition. Optically Stimulated Luminescence dating of alluvial fan and floodplain sedimentary units was conducted, for analysis of river-floodplain long-term history (100s to 1 000s of years). Interviews with 11 local landowners, combined with analysis of historic aerial imagery and river-floodplain topographic surveys, provided a means of describing recent (last few decades) geomorphological dynamics. The results indicated that the Baviaanskloof is naturally a cut- and-fill landscape over scales of several hundred to thousands of years, characterized by the alternation between phases of high fluvial energy and alluvial fan expansion, and low energy conditions associated with floodplain accretion. Recent and widespread river-floodplain degradation was compressed into a short period of approximately 30 years, suggesting that one or more drivers have pushed the system beyond a threshold, resulting in increased water and sediment connectivity. The second results chapter investigated the role of human land-use activities and flooding frequency and magnitude, as drivers of recent river-floodplain degradation. Human impacts were investigated by describing land-use activities for the preceding 80 years, and relating these activities to changes in river-floodplain form and behavior. Temporal trends in flood events of different frequency and magnitude were investigated by analyzing rainfall data, integrated with landowner reports of flood-inducing rainfall magnitudes. The findings indicated that human land-use activities have been an important driver of recent river- floodplain degradation, through the enhancement of water and sediment connectivity across spatial scales of the catchment. Episodic and high magnitude floods synergized with human driven increased connectivity, precipitating stream power and geomorphological threshold breaches, resulting in a shift in river behaviour. The third results chapter investigated the influence of tributary-junction streams and fans on the geomorphological form, behavior and sensitivity of the Baviaanskloof River. Local- scale topographic impacts of tributary fans and streams were described using topographic surveys and geomorphological mapping techniques. Tributary streams form a major control on the behaviour of the river, by influencing the degree of coarse sediment connectivity with the main channel. Although tributary fans buffer the river from disturbances occurring in the wider catchment, they initiate topographic variations along the floodplain, influencing local-scale patterns of deposition and erosion along the river. The main river responds to water and sediment inputs from tributary junction streams by locally adjusting longitudinal slope, maintaining an overall constant slope of 0.0066 m/m. The response of the Baviaanskloof River to tributary junction fans and streams is however variable, and is fashioned by complex interactions between geomorphological and anthropogenic factors. The final two chapters of the thesis evaluate the findings of the study within the context of river-floodplain rehabilitation approaches in South Africa, and within the theoretical, philosophical and methodological context of the research. The first of these two chapters evaluates the approach of the WfWet programme to river-floodplain rehabilitation in the Baviaanskloof. The chapter indicates that the present practice of WfWet is to reinstate a pre-degradation state, which is not suited to the Baviaanskloof River-floodplain, since the river-floodplain has passed a geomorphological threshold, resulting in a new set of interacting processes and landforms. The author presents a conceptual model illustrating the existence of geomorphological adaptive cycles interacting across spatial and temporal scales, thereby attempting to explain a river Panarchy specific to the Baviaanskloof. From this conceptual model, a hierarchical rehabilitation framework, targeting geomorphological processes and structure situated at different spatial and temporal scales of the landscape is suggested. The final chapter discusses the implications of integrating the concepts of geomorphological connectivity and river Panarchy theory in studies of river complexity and sensitivity to geomorphological change. The author suggests that there is scope for further investigation of the application of the two concepts within the discipline of fluvial geomorphology, particularly with regard to developing quantitative approaches to measuring and describing connectivity and Panarchy.
- Full Text:
- Date Issued: 2017
Germinating in the cracks: the identity of contemporary Zambian art
- Authors: Mulenga, Andrew
- Date: 2017
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146222 , vital:38506 , ISBN 9783863883065
- Description: Culture is the heritage of us all. Some may be more interested than others in the treasures of the past, but no one can fail to take pride in his country's participation in the story of mankind as represented in carvings, sculpture, music, painting, and the other arts (Simon Mwansa Kapwepwe 1964). After gaining independence in 1964, the next move for Zambia, like most newly-born African states at the time, was nation-building.
- Full Text:
- Date Issued: 2017
- Authors: Mulenga, Andrew
- Date: 2017
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146222 , vital:38506 , ISBN 9783863883065
- Description: Culture is the heritage of us all. Some may be more interested than others in the treasures of the past, but no one can fail to take pride in his country's participation in the story of mankind as represented in carvings, sculpture, music, painting, and the other arts (Simon Mwansa Kapwepwe 1964). After gaining independence in 1964, the next move for Zambia, like most newly-born African states at the time, was nation-building.
- Full Text:
- Date Issued: 2017
Germinating in the cracks: the identity of contemporary Zambian art
- Authors: Mulenga, Andrew
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146734 , vital:38552 , http://www.nationalgallery.co.zw/icac/
- Description: The theme of the 2017 conference is Mapping the Future. We hope to gather art and culture professionals, academics, writers, critics and others in order to map out the future of art, culture and heritage from Africa. It will provide various players with an opportunity to interrogate the future of art institutions in the face of the current socio-economic challenges. Today the situation has changed since the first ICAC and the challenges that were there in the sixties, seventies and eighties are not the same today. ICAC comes at a time when art institutions around the world need urgent attention from both the local authorities, corporations and their governments.
- Full Text:
- Date Issued: 2017
- Authors: Mulenga, Andrew
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146734 , vital:38552 , http://www.nationalgallery.co.zw/icac/
- Description: The theme of the 2017 conference is Mapping the Future. We hope to gather art and culture professionals, academics, writers, critics and others in order to map out the future of art, culture and heritage from Africa. It will provide various players with an opportunity to interrogate the future of art institutions in the face of the current socio-economic challenges. Today the situation has changed since the first ICAC and the challenges that were there in the sixties, seventies and eighties are not the same today. ICAC comes at a time when art institutions around the world need urgent attention from both the local authorities, corporations and their governments.
- Full Text:
- Date Issued: 2017
Girl-child education in marginalised rural communities : a critical study of threats and opportunities to access quality secondary education in Binga District, Zimbabwe
- Authors: Nyamanhare, Eurita
- Date: 2017
- Subjects: Gender identity in education -- Zimbabwe Sex discrimination in education -- Zimbabwe Girls -- Education -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/9213 , vital:34306
- Description: Despite the high ratings of the Zimbabwe’s education system in Africa, the state of secondary education in Binga District epitomises ‘a neglected backyard’ serving to perpetuate secondary education attainment inequalities, with the girl-child fixed at the bottom of the ladder at secondary school level. The prevailing deplorable learning conditions that characterise marginalised rural communities, mainly dominated by minority ethnic groups in Zimbabwe, depict similar conditions under which a girl-child strives to attain quality secondary education in some underdeveloped and developing African countries. Girl-Child Education in Marginalised Rural Communities: A Critical Study of Threats and Opportunities to Access Quality Secondary Education in Binga district, Zimbabwe, adopted a qualitative approach underpinned by a transformative paradigm. Pierre Bourdieu’s cultural capital and Kimberle Crenshaw’s intersectionality theoretical concepts complemented each other providing the theoretical lens that assisted in the unpacking of the whole study. Thus, the adopted theoretical framework helped the researcher to critique the seemingly ‘legitimised’ intergenerational multiple inequalities perpetuated through the education system and the intersecting systems of power (ethnicity, gender, social class) that consequently led to the unpacking of issues that surrounded the girl-child’s access to quality secondary education in Binga District. Intensive literature discussion covered the main themes derived from the study’s research questions, providing the ground from which new knowledge was nourished. With a sufficiently complex phenomenological-emergent research design embedded within critical studies, thick descriptions of lived experiences were gathered from 18 in-depth individual interviews and 6 Focus Group Discussions that involved the girls themselves; all considered to be ‘leaders of opinion’ in this study because of the various social positions and roles they played. Observations, visual materials in the form of photographs, as well as documents and records completed the list of data gathering tools that led to robust trustworthy credible findings from which the main themes of the study emerged. For the girl-child in Binga District, access to quality secondary education was found to be marginalised due to questionable gender responsiveness emanating from the social and infrastructure environments, the girl-child’s negative notions of secondary education underpinned by intersecting barriers, opportunities that are overshadowed by unmatched commitment by the girl-child seemingly underpinned by intersecting unresolved threats exacerbated by distant transitional prospects beyond secondary education. As put by one of the participants, thus, an analogy of ‘an incubator that ceases to work before the eggs hatch’ could be used to describe the state of secondary educational environment under which a girl-child strived to access quality secondary education in Binga District. Thus, using Binga District in Zimbabwe to mirror the state of secondary education in the ‘backyards’ of most of the sub-Saharan African countries, this study urges all African governments to take responsibility as they revise and enforce existing policies in line with the 2015 United Nations Sustainable Development Goals for girl-child secondary education is endowed with unlimited socio-economic benefits to all individual nations, and globally.
- Full Text:
- Date Issued: 2017
- Authors: Nyamanhare, Eurita
- Date: 2017
- Subjects: Gender identity in education -- Zimbabwe Sex discrimination in education -- Zimbabwe Girls -- Education -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , Education
- Identifier: http://hdl.handle.net/10353/9213 , vital:34306
- Description: Despite the high ratings of the Zimbabwe’s education system in Africa, the state of secondary education in Binga District epitomises ‘a neglected backyard’ serving to perpetuate secondary education attainment inequalities, with the girl-child fixed at the bottom of the ladder at secondary school level. The prevailing deplorable learning conditions that characterise marginalised rural communities, mainly dominated by minority ethnic groups in Zimbabwe, depict similar conditions under which a girl-child strives to attain quality secondary education in some underdeveloped and developing African countries. Girl-Child Education in Marginalised Rural Communities: A Critical Study of Threats and Opportunities to Access Quality Secondary Education in Binga district, Zimbabwe, adopted a qualitative approach underpinned by a transformative paradigm. Pierre Bourdieu’s cultural capital and Kimberle Crenshaw’s intersectionality theoretical concepts complemented each other providing the theoretical lens that assisted in the unpacking of the whole study. Thus, the adopted theoretical framework helped the researcher to critique the seemingly ‘legitimised’ intergenerational multiple inequalities perpetuated through the education system and the intersecting systems of power (ethnicity, gender, social class) that consequently led to the unpacking of issues that surrounded the girl-child’s access to quality secondary education in Binga District. Intensive literature discussion covered the main themes derived from the study’s research questions, providing the ground from which new knowledge was nourished. With a sufficiently complex phenomenological-emergent research design embedded within critical studies, thick descriptions of lived experiences were gathered from 18 in-depth individual interviews and 6 Focus Group Discussions that involved the girls themselves; all considered to be ‘leaders of opinion’ in this study because of the various social positions and roles they played. Observations, visual materials in the form of photographs, as well as documents and records completed the list of data gathering tools that led to robust trustworthy credible findings from which the main themes of the study emerged. For the girl-child in Binga District, access to quality secondary education was found to be marginalised due to questionable gender responsiveness emanating from the social and infrastructure environments, the girl-child’s negative notions of secondary education underpinned by intersecting barriers, opportunities that are overshadowed by unmatched commitment by the girl-child seemingly underpinned by intersecting unresolved threats exacerbated by distant transitional prospects beyond secondary education. As put by one of the participants, thus, an analogy of ‘an incubator that ceases to work before the eggs hatch’ could be used to describe the state of secondary educational environment under which a girl-child strived to access quality secondary education in Binga District. Thus, using Binga District in Zimbabwe to mirror the state of secondary education in the ‘backyards’ of most of the sub-Saharan African countries, this study urges all African governments to take responsibility as they revise and enforce existing policies in line with the 2015 United Nations Sustainable Development Goals for girl-child secondary education is endowed with unlimited socio-economic benefits to all individual nations, and globally.
- Full Text:
- Date Issued: 2017
Governing information security within the context of "bring your own device" in small, medium and micro enterprises
- Authors: Fani, Noluvuyo
- Date: 2017
- Subjects: Data protection , Computer security -- Management , Computer networks -- Security measures
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/7626 , vital:22114
- Description: Throughout history, information has been core to the communication, processing and storage of most tasks in the organisation, in this case in Small-Medium and Micro Enterprises (SMMEs). The implementation of these tasks relies on Information and Communication Technology (ICT). ICT is constantly evolving, and with each developed ICT, it becomes important that organisations adapt to the changing environment. Organisations need to adapt to the changing environment by incorporating innovative ICT that allows employees to perform their tasks with ease anywhere and anytime, whilst reducing the costs affiliated with the ICT. In this modern, performing tasks with ease anywhere and anytime requires that the employee is mobile whilst using the ICT. As a result, a relatively new phenomenon called “Bring Your Own Device” (BYOD) is currently infiltrating most organisations, where personally-owned mobile devices are used to access organisational information that will be used to conduct the various tasks of the organisation. The use of BYOD in organisations breeds the previously mentioned benefits such as performing organisational tasks anywhere and anytime. However, with the benefits highlighted for BYOD, organisations should be aware that there are risks to the implementation of BYOD. Therefore, the implementation of BYOD deems that organisations should implement BYOD with proper management thereof.
- Full Text:
- Date Issued: 2017
- Authors: Fani, Noluvuyo
- Date: 2017
- Subjects: Data protection , Computer security -- Management , Computer networks -- Security measures
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/7626 , vital:22114
- Description: Throughout history, information has been core to the communication, processing and storage of most tasks in the organisation, in this case in Small-Medium and Micro Enterprises (SMMEs). The implementation of these tasks relies on Information and Communication Technology (ICT). ICT is constantly evolving, and with each developed ICT, it becomes important that organisations adapt to the changing environment. Organisations need to adapt to the changing environment by incorporating innovative ICT that allows employees to perform their tasks with ease anywhere and anytime, whilst reducing the costs affiliated with the ICT. In this modern, performing tasks with ease anywhere and anytime requires that the employee is mobile whilst using the ICT. As a result, a relatively new phenomenon called “Bring Your Own Device” (BYOD) is currently infiltrating most organisations, where personally-owned mobile devices are used to access organisational information that will be used to conduct the various tasks of the organisation. The use of BYOD in organisations breeds the previously mentioned benefits such as performing organisational tasks anywhere and anytime. However, with the benefits highlighted for BYOD, organisations should be aware that there are risks to the implementation of BYOD. Therefore, the implementation of BYOD deems that organisations should implement BYOD with proper management thereof.
- Full Text:
- Date Issued: 2017
Graphene quantum dot-phthalocyanine polystyrene conjugate embedded in asymmetric polymer membranes for photocatalytic oxidation of 4-chlorophenol
- Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189189 , vital:44825 , xlink:href="https://doi.org/10.1080/00958972.2017.1400664"
- Description: The feasibility of using π–π stacking as a means of fixing unsubstituted Zn phthalocyanine (ZnPc) to a support prior to formation of photoactive polymer asymmetric membranes was explored. Stable ZnPc–graphene quantum dot-polystyrene conjugates (6.15 μmol/g ZnPc loading) were synthesized and embedded in polystyrene membranes which proved to be photoactive with a singlet oxygen quantum yield of 0.43 in ethanol and 0.37 in water. The membranes also proved to be active in the photocatalytic oxidation of 4-chlorophenol in water where the reaction followed second-order kinetics. At 3.24 × 10−4 mol L−1, the photo-oxidation of 4-chlorophenol was observed with a kobs of 35.9 L mol−1 min−1 and a half-life of 86 min.
- Full Text:
- Date Issued: 2017
- Authors: Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189189 , vital:44825 , xlink:href="https://doi.org/10.1080/00958972.2017.1400664"
- Description: The feasibility of using π–π stacking as a means of fixing unsubstituted Zn phthalocyanine (ZnPc) to a support prior to formation of photoactive polymer asymmetric membranes was explored. Stable ZnPc–graphene quantum dot-polystyrene conjugates (6.15 μmol/g ZnPc loading) were synthesized and embedded in polystyrene membranes which proved to be photoactive with a singlet oxygen quantum yield of 0.43 in ethanol and 0.37 in water. The membranes also proved to be active in the photocatalytic oxidation of 4-chlorophenol in water where the reaction followed second-order kinetics. At 3.24 × 10−4 mol L−1, the photo-oxidation of 4-chlorophenol was observed with a kobs of 35.9 L mol−1 min−1 and a half-life of 86 min.
- Full Text:
- Date Issued: 2017
Graphene quantum dots anchored onto mercaptopyridine-substituted zinc phthalocyanine-Au@ Ag nanoparticle hybrid: Application as fluorescence “off-on-off” sensor for Hg2+ and biothiols
- Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188194 , vital:44731 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.06.002"
- Description: Novel supramolecular hybrid containing polyethyleneimine-functionalized graphene quantum dots (PEI-GQDs) and mercaptopyridine-substituted zinc phthalocyanine (Pc)-Au@Ag nano-alloys is presented in this study. The designed hybrid was employed as a dual fluorescence nanoprobe for Hg2+ and biothiol detection in aqueous solution using PEI-GQDs as the fluorescence switching signal probe. The dual sensing platform for the analytes detection is firstly, based on the quenching (turn “OFF”) of the PEI-GQDs fluorescence upon π-π interaction or electrostatic attraction with Pc-Au@Ag conjugate. The quenched fluorescence can be switched back to the “ON” mode in the presence of Hg2+ and switched “OFF” again when biothiols are introduced to capture the Hg2+ ion via the formation of the strong metal-thiol bond (Hg-S). The “off-on-off” processes were modulated by different amounts of Hg2+ and biothiols. The nanoprobes were found to be highly stable and selective towards the target analytes in the presence of other amino acids and metal ions. Also, the probes were successfully deployed in the assay of the test analytes in spiked samples.
- Full Text:
- Date Issued: 2017
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188194 , vital:44731 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.06.002"
- Description: Novel supramolecular hybrid containing polyethyleneimine-functionalized graphene quantum dots (PEI-GQDs) and mercaptopyridine-substituted zinc phthalocyanine (Pc)-Au@Ag nano-alloys is presented in this study. The designed hybrid was employed as a dual fluorescence nanoprobe for Hg2+ and biothiol detection in aqueous solution using PEI-GQDs as the fluorescence switching signal probe. The dual sensing platform for the analytes detection is firstly, based on the quenching (turn “OFF”) of the PEI-GQDs fluorescence upon π-π interaction or electrostatic attraction with Pc-Au@Ag conjugate. The quenched fluorescence can be switched back to the “ON” mode in the presence of Hg2+ and switched “OFF” again when biothiols are introduced to capture the Hg2+ ion via the formation of the strong metal-thiol bond (Hg-S). The “off-on-off” processes were modulated by different amounts of Hg2+ and biothiols. The nanoprobes were found to be highly stable and selective towards the target analytes in the presence of other amino acids and metal ions. Also, the probes were successfully deployed in the assay of the test analytes in spiked samples.
- Full Text:
- Date Issued: 2017
Graphene quantum dots coordinated to mercaptopyridine-substituted phthalocyanines: Characterization and application as fluorescence “turn ON” nanoprobes
- Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188293 , vital:44742 , xlink:href="https://doi.org/10.1016/j.saa.2016.11.043"
- Description: This study reports on the design of novel nanoconjugates of graphene quantum dots (GQDs) and tetra or octa-mercaptopyridine-substituted zinc and aluminium phthalocyanines (Pcs) deployed as fluorescence “turn ON” nanoprobes. The phthalocyanines were separately adsorbed onto the planar structure of graphene quantum dots (GQDs) via π-π stacking interaction to form GQDs-mercaptopyridine Pcs nanoconjugates. The quaternized Pc complexes could also interact with the GQDs through electrostatic attraction due to the positive charges on the Pcs ring substituents and the negative charges on the surface of GQDs. The fluorescence emission of the GQDs was quenched upon coordination to the respective Pcs. However, the fluorescence emission was “turned ON” in the presence of Hg2 + employed as a test analyte. The mechanism of the “turn ON” of the GQDs emission in the nanoconjugates is ascribed to the strong affinity of Hg2 + to bind with the bridging sulfur on the Pcs periphery thereby disrupting the π-π stacking interaction between the GQDs and the Pcs with a consequent “turn ON” of the coordinated GQDs' fluorescence.
- Full Text:
- Date Issued: 2017
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188293 , vital:44742 , xlink:href="https://doi.org/10.1016/j.saa.2016.11.043"
- Description: This study reports on the design of novel nanoconjugates of graphene quantum dots (GQDs) and tetra or octa-mercaptopyridine-substituted zinc and aluminium phthalocyanines (Pcs) deployed as fluorescence “turn ON” nanoprobes. The phthalocyanines were separately adsorbed onto the planar structure of graphene quantum dots (GQDs) via π-π stacking interaction to form GQDs-mercaptopyridine Pcs nanoconjugates. The quaternized Pc complexes could also interact with the GQDs through electrostatic attraction due to the positive charges on the Pcs ring substituents and the negative charges on the surface of GQDs. The fluorescence emission of the GQDs was quenched upon coordination to the respective Pcs. However, the fluorescence emission was “turned ON” in the presence of Hg2 + employed as a test analyte. The mechanism of the “turn ON” of the GQDs emission in the nanoconjugates is ascribed to the strong affinity of Hg2 + to bind with the bridging sulfur on the Pcs periphery thereby disrupting the π-π stacking interaction between the GQDs and the Pcs with a consequent “turn ON” of the coordinated GQDs' fluorescence.
- Full Text:
- Date Issued: 2017
Graphene quantum dots decorated with maleimide and zinc tetramaleimido-phthalocyanine: Application in the design of “OFF-ON” fluorescence sensors for biothiols
- Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188282 , vital:44741 , xlink:href="https://doi.org/10.1016/j.talanta.2017.01.031"
- Description: The fabrication of maleimide-derivatized graphene quantum dots (M-GQDs) and zinc phthalocyanine (2) as novel sensor probes for the selective detection of biothiols (cysteine, homocysteine or glutathione) through the rapid and specific Michael addition reaction between biothiols and the maleimide-derivatized probes is presented in this study. GQDs directly functionalized with maleimide units (M-GQDs) were synthesized and deployed for biothiols recognition following the principle of Michael addition. M-GQDs probe was found to be highly sensitive and selective towards biothiols detection in the nanomolar range in aqueous solution and at physiological pH (7.0). On the other hand, non-covalent interaction between pristine GQDs and novel zinc tetramaleimido-derivatized phthalocyanine resulted in the quenching of the pristine GQDs fluorescence emission which was switched back to the “ON” mode by Michael addition mechanism in the presence of biothiols. Tested relevant biomolecules did not interfere in the quantitative recognition of the biothiols. The probes showed to be highly sensitive, specific and selective for biothiols sensing in simulated real samples.
- Full Text:
- Date Issued: 2017
- Authors: Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188282 , vital:44741 , xlink:href="https://doi.org/10.1016/j.talanta.2017.01.031"
- Description: The fabrication of maleimide-derivatized graphene quantum dots (M-GQDs) and zinc phthalocyanine (2) as novel sensor probes for the selective detection of biothiols (cysteine, homocysteine or glutathione) through the rapid and specific Michael addition reaction between biothiols and the maleimide-derivatized probes is presented in this study. GQDs directly functionalized with maleimide units (M-GQDs) were synthesized and deployed for biothiols recognition following the principle of Michael addition. M-GQDs probe was found to be highly sensitive and selective towards biothiols detection in the nanomolar range in aqueous solution and at physiological pH (7.0). On the other hand, non-covalent interaction between pristine GQDs and novel zinc tetramaleimido-derivatized phthalocyanine resulted in the quenching of the pristine GQDs fluorescence emission which was switched back to the “ON” mode by Michael addition mechanism in the presence of biothiols. Tested relevant biomolecules did not interfere in the quantitative recognition of the biothiols. The probes showed to be highly sensitive, specific and selective for biothiols sensing in simulated real samples.
- Full Text:
- Date Issued: 2017
Group membership and collective action among small-scale farmers in Nkonkobe Local Municipality, Eastern Cape Province, South Africa
- Authors: Arwari, Margaret Kwamboka
- Date: 2017
- Subjects: Farmers -- South Africa -- Eastern Cape Farms, Small -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8144 , vital:31535
- Description: In South Africa, the organisation of farmers into groups has been a basic tenet for numerous, small and dispersed small-scale farmers to make their voices heard, address challenges and access support services from the government and other development agencies. However, the literature shows that the South African government promotes inappropriate forms of farmer collective action, i.e. collective production. The government seems to lack knowledge on what forms of collective action to implement and support. It is also noted in the literature that in South Africa, the majority of farmers do not participate in farmer organisations. There is limited research on the determinants of membership in farmer organisations, especially in terms of the role of ‘human agency’. Human agency is a concept which is interrelated with the concept of ‘empowerme nt’, whereby a person with strong agency is someone who is an agent of positive change. Therefore, the study sought to address these gaps. The broad objective of this study was to explore the phenomenon of group membership and collective action among small-scale farmers in Nkonkobe Local Municipality, Eastern Cape Province, South Africa. The study used the mixed method approach where an exploratory design was employed. A mult istage sampling technique was used which employed random, purposive and convenience sampling techniques. Quantitative and qualitative data were collected from 245 farmers using semistructured questionnaires and detailed qualitative data were elicited from 16 farmer organisat ions using interview guides. For the quantitative research, a cross-sectional survey design was employed. After discarded unusable observations, data from 228 farmers were analysed using a combination of descriptive statistics, simple inferential statistics, and econometric analysis. For the qualitative data obtained, thematic analysis was used in line with the study objectives. The study findings show that farmers undertake collective action through farmer organisations. These farmer organisations were categorised into two types, i.e. farmer cooperatives and farmer associations. However, low membership in these farmer organisations is noted and this was attributed to the following: (1) low farmer awareness of the existence of farmer organisations, (2) challenges faced by the organisations that contribute to their ineffectiveness and thus low membership, (3) the prevalence of negative perceptions of farmer organisations due to confusion as to their role, (4) the government’s farmer support approach which compels or encourages farmers to form groups. The results also showed that the following are determinants of participation in farmer organisations: farmer’s age, level of education, human agency, whether a farmer has off-farm income sources, whether a farmer is involved in government supported projects, whether a farmer accesses extension information, the number of visits from extension officers received by a farmer, and the number of adults in a household contributing family labour. The study findings also show that the farmers in farmer organisations have higher human agency compared to those not in farmer organisations. According to the study results, farmer groups offer a number of benefits. For one, farmer organisations are avenues for farmers’ voices to be heard, they lobby government for better access to support services such as credit, input supply, information, and training. In addition, farmers who belong to organisations experience the benefits of collective marketing. Despite the aforementioned benefits of farmer organisations, group challenges are observed. For example, farmer organisations face declining membership, the free rider problem and conflicts between members, have a problem of ineffective, old members and lack of commitment of some group members. It was therefore recommended that there is a need for concerted effort by the government, development agencies, non-governmental organisations, farmers, and farmer organisations to ensure the success of farmer organisations in promoting small-scale agriculture.
- Full Text:
- Date Issued: 2017
- Authors: Arwari, Margaret Kwamboka
- Date: 2017
- Subjects: Farmers -- South Africa -- Eastern Cape Farms, Small -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8144 , vital:31535
- Description: In South Africa, the organisation of farmers into groups has been a basic tenet for numerous, small and dispersed small-scale farmers to make their voices heard, address challenges and access support services from the government and other development agencies. However, the literature shows that the South African government promotes inappropriate forms of farmer collective action, i.e. collective production. The government seems to lack knowledge on what forms of collective action to implement and support. It is also noted in the literature that in South Africa, the majority of farmers do not participate in farmer organisations. There is limited research on the determinants of membership in farmer organisations, especially in terms of the role of ‘human agency’. Human agency is a concept which is interrelated with the concept of ‘empowerme nt’, whereby a person with strong agency is someone who is an agent of positive change. Therefore, the study sought to address these gaps. The broad objective of this study was to explore the phenomenon of group membership and collective action among small-scale farmers in Nkonkobe Local Municipality, Eastern Cape Province, South Africa. The study used the mixed method approach where an exploratory design was employed. A mult istage sampling technique was used which employed random, purposive and convenience sampling techniques. Quantitative and qualitative data were collected from 245 farmers using semistructured questionnaires and detailed qualitative data were elicited from 16 farmer organisat ions using interview guides. For the quantitative research, a cross-sectional survey design was employed. After discarded unusable observations, data from 228 farmers were analysed using a combination of descriptive statistics, simple inferential statistics, and econometric analysis. For the qualitative data obtained, thematic analysis was used in line with the study objectives. The study findings show that farmers undertake collective action through farmer organisations. These farmer organisations were categorised into two types, i.e. farmer cooperatives and farmer associations. However, low membership in these farmer organisations is noted and this was attributed to the following: (1) low farmer awareness of the existence of farmer organisations, (2) challenges faced by the organisations that contribute to their ineffectiveness and thus low membership, (3) the prevalence of negative perceptions of farmer organisations due to confusion as to their role, (4) the government’s farmer support approach which compels or encourages farmers to form groups. The results also showed that the following are determinants of participation in farmer organisations: farmer’s age, level of education, human agency, whether a farmer has off-farm income sources, whether a farmer is involved in government supported projects, whether a farmer accesses extension information, the number of visits from extension officers received by a farmer, and the number of adults in a household contributing family labour. The study findings also show that the farmers in farmer organisations have higher human agency compared to those not in farmer organisations. According to the study results, farmer groups offer a number of benefits. For one, farmer organisations are avenues for farmers’ voices to be heard, they lobby government for better access to support services such as credit, input supply, information, and training. In addition, farmers who belong to organisations experience the benefits of collective marketing. Despite the aforementioned benefits of farmer organisations, group challenges are observed. For example, farmer organisations face declining membership, the free rider problem and conflicts between members, have a problem of ineffective, old members and lack of commitment of some group members. It was therefore recommended that there is a need for concerted effort by the government, development agencies, non-governmental organisations, farmers, and farmer organisations to ensure the success of farmer organisations in promoting small-scale agriculture.
- Full Text:
- Date Issued: 2017
Growth strategies for black township entrepreneurs
- Authors: Boniwe, Sihlangule
- Date: 2017
- Subjects: Entrepreneurship -- South Africa , Small business -- South Africa -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/14598 , vital:27800
- Description: The situation in South Africa throws up a trickier and more unconventional challenge. The country has symptoms of a spatial realm that is not fully connected with the urban systems (spatially, socially, or structurally) and is certainly disconnected from the rural economy. This is the realm of the country’s townships and informal settlements. Conceptually, they are relics of the country’s special past, but the policies of post-apartheid South Africa have inadvertently kept their contemporary reality alive. In many ways, the townships and especially the informal settlements are similar to the slums in much of the developing world, although never was a slum formed with as much central planning and purpose as were some of the larger South African townships. This paper undertakes to understand the growth strategies of black township entrepreneurs in South Africa. This paper also undertakes to investigate the perceived influence of education, government policies, access to funding, market constraints, crime and social norms on the development or perceived growth strategies for black township entrepreneurs. Propositions are made and tested through conducting interviews with individuals involved with the dynamics presented by this subject on a day to day basis. Evidence collected is interpreted into knowledge and finally recommendations are made.
- Full Text:
- Date Issued: 2017
- Authors: Boniwe, Sihlangule
- Date: 2017
- Subjects: Entrepreneurship -- South Africa , Small business -- South Africa -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/14598 , vital:27800
- Description: The situation in South Africa throws up a trickier and more unconventional challenge. The country has symptoms of a spatial realm that is not fully connected with the urban systems (spatially, socially, or structurally) and is certainly disconnected from the rural economy. This is the realm of the country’s townships and informal settlements. Conceptually, they are relics of the country’s special past, but the policies of post-apartheid South Africa have inadvertently kept their contemporary reality alive. In many ways, the townships and especially the informal settlements are similar to the slums in much of the developing world, although never was a slum formed with as much central planning and purpose as were some of the larger South African townships. This paper undertakes to understand the growth strategies of black township entrepreneurs in South Africa. This paper also undertakes to investigate the perceived influence of education, government policies, access to funding, market constraints, crime and social norms on the development or perceived growth strategies for black township entrepreneurs. Propositions are made and tested through conducting interviews with individuals involved with the dynamics presented by this subject on a day to day basis. Evidence collected is interpreted into knowledge and finally recommendations are made.
- Full Text:
- Date Issued: 2017
Guidelines for cybersecurity education campaigns
- Authors: Reid, Rayne
- Date: 2017
- Subjects: Computer security Computer networks -- Security measures
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/14091 , vital:27416
- Description: In our technology- and information-infused world, cyberspace is an integral part of modern-day society. As the number of active cyberspace users increases, so too does the chances of a cyber threat finding a vulnerable target increase. All cyber users who are exposed to cyber risks need to be educated about cyber security. Human beings play a key role in the implementation and governing of an entire cybersecurity and cybersafety solution. The effectiveness of any cybersecurity and cybersafety solutions in a societal or individual context is dependent on the human beings involved in the process. If these human beings are either unaware or not knowledgeable about their roles in the security solution they become the weak link in these cybersecurity solutions. It is essential that all users be educated to combat any threats. Children are a particularly vulnerable subgroup within society. They are digital natives and make use of ICT, and online services with increasing frequency, but this does not mean they are knowledgeable about or behaving securely in their cyber activities. Children will be exposed to cyberspace throughout their lifetimes. Therefore, cybersecurity and cybersafety should be taught to children as a life-skill. There is a lack of well-known, comprehensive cybersecurity and cybersafety educational campaigns which target school children. Most existing information security and cybersecurity education campaigns limit their scope. Literature reports mainly on education campaigns focused on primary businesses, government agencies and tertiary education institutions. Additionally, most guidance for the design and implementation of security and safety campaigns: are for an organisational context, only target organisational users, and mostly provide high-level design recommendations. This thesis addressed the lack of guidance for designing and implementing cybersecurity and cybersafety educational campaigns suited to school learners as a target audience. The thesis aimed to offer guidance for designing and implementing education campaigns that educate school learners about cybersecurity and cybersafety. This was done through the implementation of an action research process over a five-year period. The action research process involved cybersecurity and cybersafety educational interventions at multiple schools. A total of 18 actionable guidelines were derived from this research to guide the design and implementation of cybersecurity and cybersafety education campaigns which aim to educate school children.
- Full Text:
- Date Issued: 2017
- Authors: Reid, Rayne
- Date: 2017
- Subjects: Computer security Computer networks -- Security measures
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/14091 , vital:27416
- Description: In our technology- and information-infused world, cyberspace is an integral part of modern-day society. As the number of active cyberspace users increases, so too does the chances of a cyber threat finding a vulnerable target increase. All cyber users who are exposed to cyber risks need to be educated about cyber security. Human beings play a key role in the implementation and governing of an entire cybersecurity and cybersafety solution. The effectiveness of any cybersecurity and cybersafety solutions in a societal or individual context is dependent on the human beings involved in the process. If these human beings are either unaware or not knowledgeable about their roles in the security solution they become the weak link in these cybersecurity solutions. It is essential that all users be educated to combat any threats. Children are a particularly vulnerable subgroup within society. They are digital natives and make use of ICT, and online services with increasing frequency, but this does not mean they are knowledgeable about or behaving securely in their cyber activities. Children will be exposed to cyberspace throughout their lifetimes. Therefore, cybersecurity and cybersafety should be taught to children as a life-skill. There is a lack of well-known, comprehensive cybersecurity and cybersafety educational campaigns which target school children. Most existing information security and cybersecurity education campaigns limit their scope. Literature reports mainly on education campaigns focused on primary businesses, government agencies and tertiary education institutions. Additionally, most guidance for the design and implementation of security and safety campaigns: are for an organisational context, only target organisational users, and mostly provide high-level design recommendations. This thesis addressed the lack of guidance for designing and implementing cybersecurity and cybersafety educational campaigns suited to school learners as a target audience. The thesis aimed to offer guidance for designing and implementing education campaigns that educate school learners about cybersecurity and cybersafety. This was done through the implementation of an action research process over a five-year period. The action research process involved cybersecurity and cybersafety educational interventions at multiple schools. A total of 18 actionable guidelines were derived from this research to guide the design and implementation of cybersecurity and cybersafety education campaigns which aim to educate school children.
- Full Text:
- Date Issued: 2017
Guidelines for secure cloud-based personal health records
- Authors: Mxoli, Ncedisa Avuya Mercia
- Date: 2017
- Subjects: Cloud computing -- Security measures , Computer security Data mining Medical records -- Data processing
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/14134 , vital:27433
- Description: Traditionally, health records have been stored in paper folders at the physician’s consulting rooms – or at the patient’s home. Some people stored the health records of their family members, so as to keep a running history of all the medical procedures they went through, and what medications they were given by different physicians at different stages of their lives. Technology has introduced better and safer ways of storing these records, namely, through the use of Personal Health Records (PHRs). With time, different types of PHRs have emerged, i.e. local, remote server-based, and hybrid PHRs. Web-based PHRs fall under the remote server-based PHRs; and recently, a new market in storing PHRs has emerged. Cloud computing has become a trend in storing PHRs in a more accessible and efficient manner. Despite its many benefits, cloud computing has many privacy and security concerns. As a result, the adoption rate of cloud services is not yet very high. A qualitative and exploratory research design approach was followed in this study, in order to reach the objective of proposing guidelines that could assist PHR providers in selecting a secure Cloud Service Provider (CSP) to store their customers’ health data. The research methods that were used include a literature review, systematic literature review, qualitative content analysis, reasoning, argumentation and elite interviews. A systematic literature review and qualitative content analysis were conducted to examine those risks in the cloud environment that could have a negative impact on the secure storing of PHRs. PHRs must satisfy certain dimensions, in order for them to be meaningful for use. While these were highlighted in the research, it also emerged that certain risks affect the PHR dimensions directly, thus threatening the meaningfulness and usability of cloud-based PHRs. The literature review revealed that specific control measures can be adopted to mitigate the identified risks. These control measures form part of the material used in this study to identify the guidelines for secure cloud-based PHRs. The guidelines were formulated through the use of reasoning and argumentation. After the guidelines were formulated, elite interviews were conducted, in order to validate and finalize the main research output: i.e. guidelines. The results of this study may alert PHR providers to the risks that exist in the cloud environment; so that they can make informed decisions when choosing a CSP for storing their customers’ health data.
- Full Text:
- Date Issued: 2017
- Authors: Mxoli, Ncedisa Avuya Mercia
- Date: 2017
- Subjects: Cloud computing -- Security measures , Computer security Data mining Medical records -- Data processing
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/14134 , vital:27433
- Description: Traditionally, health records have been stored in paper folders at the physician’s consulting rooms – or at the patient’s home. Some people stored the health records of their family members, so as to keep a running history of all the medical procedures they went through, and what medications they were given by different physicians at different stages of their lives. Technology has introduced better and safer ways of storing these records, namely, through the use of Personal Health Records (PHRs). With time, different types of PHRs have emerged, i.e. local, remote server-based, and hybrid PHRs. Web-based PHRs fall under the remote server-based PHRs; and recently, a new market in storing PHRs has emerged. Cloud computing has become a trend in storing PHRs in a more accessible and efficient manner. Despite its many benefits, cloud computing has many privacy and security concerns. As a result, the adoption rate of cloud services is not yet very high. A qualitative and exploratory research design approach was followed in this study, in order to reach the objective of proposing guidelines that could assist PHR providers in selecting a secure Cloud Service Provider (CSP) to store their customers’ health data. The research methods that were used include a literature review, systematic literature review, qualitative content analysis, reasoning, argumentation and elite interviews. A systematic literature review and qualitative content analysis were conducted to examine those risks in the cloud environment that could have a negative impact on the secure storing of PHRs. PHRs must satisfy certain dimensions, in order for them to be meaningful for use. While these were highlighted in the research, it also emerged that certain risks affect the PHR dimensions directly, thus threatening the meaningfulness and usability of cloud-based PHRs. The literature review revealed that specific control measures can be adopted to mitigate the identified risks. These control measures form part of the material used in this study to identify the guidelines for secure cloud-based PHRs. The guidelines were formulated through the use of reasoning and argumentation. After the guidelines were formulated, elite interviews were conducted, in order to validate and finalize the main research output: i.e. guidelines. The results of this study may alert PHR providers to the risks that exist in the cloud environment; so that they can make informed decisions when choosing a CSP for storing their customers’ health data.
- Full Text:
- Date Issued: 2017
Gypsum deposits associated with the Whitehill Formation (Ecca Group) in the Steytlerville-Jansenville Area, Southern Karoo, South Africa
- Authors: Almanza, Roberto Daniel
- Date: 2017
- Subjects: Gypsum -- South Africa Concretions -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/15292 , vital:28215
- Description: The Steyterville-Jansenville gypsum field is one of South Africa’s smaller deposits, yet plays host to several gypsum mines, both past and present. This study aims to deconstruct the processes involved in the precipitation of various quantities and grades of gypsum in the lower Ecca Group of the Karoo Supergroup. The calcium and sulphate ions required to form the gypsum mineral (CaSO4•2H2O) are derived from the mid- to lower-shale of the Whitehill Formation, which is carbonate- and pyrite-rich. Gypsum formation is dependent on the availability of pyrite as opposed to calcite, which is in abundance throughout the 30m thick, Early Ufimian (late Permian) Whitehill Formation. Weathered shale, which has been folded and faulted, forms the host environment in which gypsum has precipitated. Folding of the shale occurs as a series of large- and medium-scale anticlines and synclines that strike east to west. These structures, which formed during the Cape Orogeny indicate that stresses were exerted from the south-southwest towards the north-northeast. Folded calcite veins surrounded by amorphous pyrite, observed in thin section suggest that pyrite and calcite were precipitated together prior to a deformation event. Oxidation of pyrite following these deformation events results in the concentration of sulphides within the hinge zones of the folds (weakest zone) and this is where the larger gypsum deposits are found at the surface. Carbonate concretions in the Whitehill Formation up to 5m in length and 3m in width are common in the study area, and suggest a relationship with the deposition of the shale whereby calcium-rich nuclei grew in a concentric fashion during a non-depositional hiatus period. This period is also associated with a higher concentration of pyrite and could explain the occurrence of concretions together with adjacent gypsum-rich shale. Pyrite framboids observed under the Scanning Electron Microscope (SEM) provide evidence to suggest concentric growth of initially deposited microcrystals including nucleation and growth of nodules and concretions observed within the Whitehill Formation. Prerequisites for gypsum formation also include restricted drainage such as a pan, a clay layer in the drainage area and an arid climate where evaporation exceeds precipitation. The preferred surface conditions for gypsum formation would be low-lying areas which are surrounded by gently-sloping topography promoting the concentration of aqueous solutions in a calcite- and pyrite-rich area. Groundwater solution would initially dissolve the calcite and clay minerals, and pyrite and the quartz minerals would remain in the host rock. Areas with greater calcite and clay pores would accommodate more groundwater and thus promote a greater surface area for chemical reactions. This enhances the potential for the oxidation of pyrite to form sulphate ions, which can later combine with calcium ions to precipitate gypsum crystals. Alternatively, the oxidation of pyrite, which produces acidity, dissolves the carbonate host and the calcium- and sulphate-rich solution then precipitates gypsum. The combination of the structural and geomorphological processes is key to the formation of economic gypsum deposits. The potential for extensive gypsum reserves within the Steytlerville-Jansenville field remains valid, provided the target is located over a predominantly weathered Whitehill Formation outcrop, preferably in an area which has undergone extensive deformation (such as a fold hinge zone), and is favourable for the concentration of ground and surface water within a low-lying area.
- Full Text:
- Date Issued: 2017
- Authors: Almanza, Roberto Daniel
- Date: 2017
- Subjects: Gypsum -- South Africa Concretions -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/15292 , vital:28215
- Description: The Steyterville-Jansenville gypsum field is one of South Africa’s smaller deposits, yet plays host to several gypsum mines, both past and present. This study aims to deconstruct the processes involved in the precipitation of various quantities and grades of gypsum in the lower Ecca Group of the Karoo Supergroup. The calcium and sulphate ions required to form the gypsum mineral (CaSO4•2H2O) are derived from the mid- to lower-shale of the Whitehill Formation, which is carbonate- and pyrite-rich. Gypsum formation is dependent on the availability of pyrite as opposed to calcite, which is in abundance throughout the 30m thick, Early Ufimian (late Permian) Whitehill Formation. Weathered shale, which has been folded and faulted, forms the host environment in which gypsum has precipitated. Folding of the shale occurs as a series of large- and medium-scale anticlines and synclines that strike east to west. These structures, which formed during the Cape Orogeny indicate that stresses were exerted from the south-southwest towards the north-northeast. Folded calcite veins surrounded by amorphous pyrite, observed in thin section suggest that pyrite and calcite were precipitated together prior to a deformation event. Oxidation of pyrite following these deformation events results in the concentration of sulphides within the hinge zones of the folds (weakest zone) and this is where the larger gypsum deposits are found at the surface. Carbonate concretions in the Whitehill Formation up to 5m in length and 3m in width are common in the study area, and suggest a relationship with the deposition of the shale whereby calcium-rich nuclei grew in a concentric fashion during a non-depositional hiatus period. This period is also associated with a higher concentration of pyrite and could explain the occurrence of concretions together with adjacent gypsum-rich shale. Pyrite framboids observed under the Scanning Electron Microscope (SEM) provide evidence to suggest concentric growth of initially deposited microcrystals including nucleation and growth of nodules and concretions observed within the Whitehill Formation. Prerequisites for gypsum formation also include restricted drainage such as a pan, a clay layer in the drainage area and an arid climate where evaporation exceeds precipitation. The preferred surface conditions for gypsum formation would be low-lying areas which are surrounded by gently-sloping topography promoting the concentration of aqueous solutions in a calcite- and pyrite-rich area. Groundwater solution would initially dissolve the calcite and clay minerals, and pyrite and the quartz minerals would remain in the host rock. Areas with greater calcite and clay pores would accommodate more groundwater and thus promote a greater surface area for chemical reactions. This enhances the potential for the oxidation of pyrite to form sulphate ions, which can later combine with calcium ions to precipitate gypsum crystals. Alternatively, the oxidation of pyrite, which produces acidity, dissolves the carbonate host and the calcium- and sulphate-rich solution then precipitates gypsum. The combination of the structural and geomorphological processes is key to the formation of economic gypsum deposits. The potential for extensive gypsum reserves within the Steytlerville-Jansenville field remains valid, provided the target is located over a predominantly weathered Whitehill Formation outcrop, preferably in an area which has undergone extensive deformation (such as a fold hinge zone), and is favourable for the concentration of ground and surface water within a low-lying area.
- Full Text:
- Date Issued: 2017