An assessment of chlorophyll-a concentration spatio-temporal variation using Landsat satellite data, in a small tropical reservoir
- Dalu, Tatenda, Dube, Timothy, Froneman, P William, Sachikonye, Mwazvita T B, Clegg, Bruce W, Nhiwatiwa, Tamuka
- Authors: Dalu, Tatenda , Dube, Timothy , Froneman, P William , Sachikonye, Mwazvita T B , Clegg, Bruce W , Nhiwatiwa, Tamuka
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68042 , vital:29189 , https://doi.org/10.1080/10106049.2015.1027292
- Description: Publisher version , Traditional approaches to monitoring aquatic systems are often limited by the need for data collection which often is time-consuming, expensive and non-continuous. The aim of the study was to map the spatio-temporal chlorophyll-a concentration changes in Malilangwe Reservoir, Zimbabwe as an indicator of phytoplankton biomass and trophic state when the reservoir was full (year 2000) and at its lowest capacity (year 2011), using readily available Landsat multispectral images. Medium-spatial resolution (30 m) Landsat multispectral Thematic Mapper TM 5 and ETM+ images for May to December 1999–2000 and 2010–2011 were used to derive chlorophyll-a concentrations. In situ measured chlorophyll-a and total suspended solids (TSS) concentrations for 2011 were employed to validate the Landsat chlorophyll-a and TSS estimates. The study results indicate that Landsat-derived chlorophyll-a and TSS estimates were comparable with field measurements. There was a considerable wet vs. dry season differences in total chlorophyll-a concentration, Secchi disc depth, TSS and turbidity within the reservoir. Using Permutational multivariate analyses of variance (PERMANOVA) analysis, there were significant differences (p < 0.0001) for chlorophyll-a concentration among sites, months and years whereas TSS was significant during the study months (p < 0.05). A strong positive significant correlation among both predicted TSS vs. chlorophyll-a and measured vs. predicted chlorophyll-a and TSS concentrations as well as an inverse relationship between reservoir chlorophyll-a concentrations and water level were found (p < 0.001 in all cases). In conclusion, total chlorophyll-a concentration in Malilangwe Reservoir was successfully derived from Landsat remote sensing data suggesting that the Landsat sensor is suitable for real-time monitoring over relatively short timescales and for small reservoirs. Satellite data can allow for surveying of chlorophyll-a concentration in aquatic ecosystems, thus, providing invaluable data in data scarce (limited on site ground measurements) environments.
- Full Text: false
- Date Issued: 2015
- Authors: Dalu, Tatenda , Dube, Timothy , Froneman, P William , Sachikonye, Mwazvita T B , Clegg, Bruce W , Nhiwatiwa, Tamuka
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68042 , vital:29189 , https://doi.org/10.1080/10106049.2015.1027292
- Description: Publisher version , Traditional approaches to monitoring aquatic systems are often limited by the need for data collection which often is time-consuming, expensive and non-continuous. The aim of the study was to map the spatio-temporal chlorophyll-a concentration changes in Malilangwe Reservoir, Zimbabwe as an indicator of phytoplankton biomass and trophic state when the reservoir was full (year 2000) and at its lowest capacity (year 2011), using readily available Landsat multispectral images. Medium-spatial resolution (30 m) Landsat multispectral Thematic Mapper TM 5 and ETM+ images for May to December 1999–2000 and 2010–2011 were used to derive chlorophyll-a concentrations. In situ measured chlorophyll-a and total suspended solids (TSS) concentrations for 2011 were employed to validate the Landsat chlorophyll-a and TSS estimates. The study results indicate that Landsat-derived chlorophyll-a and TSS estimates were comparable with field measurements. There was a considerable wet vs. dry season differences in total chlorophyll-a concentration, Secchi disc depth, TSS and turbidity within the reservoir. Using Permutational multivariate analyses of variance (PERMANOVA) analysis, there were significant differences (p < 0.0001) for chlorophyll-a concentration among sites, months and years whereas TSS was significant during the study months (p < 0.05). A strong positive significant correlation among both predicted TSS vs. chlorophyll-a and measured vs. predicted chlorophyll-a and TSS concentrations as well as an inverse relationship between reservoir chlorophyll-a concentrations and water level were found (p < 0.001 in all cases). In conclusion, total chlorophyll-a concentration in Malilangwe Reservoir was successfully derived from Landsat remote sensing data suggesting that the Landsat sensor is suitable for real-time monitoring over relatively short timescales and for small reservoirs. Satellite data can allow for surveying of chlorophyll-a concentration in aquatic ecosystems, thus, providing invaluable data in data scarce (limited on site ground measurements) environments.
- Full Text: false
- Date Issued: 2015
Specific rewards for tax compliance: responses of small business owners in Ekurhuleni, South Africa
- Bornman, Marina, Stack, Elizabeth M
- Authors: Bornman, Marina , Stack, Elizabeth M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145325 , vital:38428 , https://heinonline.org/HOL/Page?handle=hein.journals/ejotaxrs13anddiv=35andg_sent=1andcasa_token=andcollection=journals
- Description: The literature reviewed documents the positive effects of rewards in encouraging desired behaviour, but rewards may have a crowding-in effect, strengthening intrinsic motivation, or a crowding-out effect, weakening it. External interventions may therefore be perceived as supportive, fostering self-esteem and self-determination, while those perceived as controlling may have the opposite effect. A number of countries have adopted a strategy of rewarding tax compliance. The rewards range from certificates awarded to compliant taxpayers, to privilege cards providing opportunities for discounts or special treatment, to lotteries in which compliant taxpayers can participate. The reward strategies are often accompanied by publicity programmes. Two such hypothetical strategies were presented to participants in a survey conducted amongst small business owners in Ekurhuleni, South Africa, to gauge their responses.
- Full Text:
- Date Issued: 2015
- Authors: Bornman, Marina , Stack, Elizabeth M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145325 , vital:38428 , https://heinonline.org/HOL/Page?handle=hein.journals/ejotaxrs13anddiv=35andg_sent=1andcasa_token=andcollection=journals
- Description: The literature reviewed documents the positive effects of rewards in encouraging desired behaviour, but rewards may have a crowding-in effect, strengthening intrinsic motivation, or a crowding-out effect, weakening it. External interventions may therefore be perceived as supportive, fostering self-esteem and self-determination, while those perceived as controlling may have the opposite effect. A number of countries have adopted a strategy of rewarding tax compliance. The rewards range from certificates awarded to compliant taxpayers, to privilege cards providing opportunities for discounts or special treatment, to lotteries in which compliant taxpayers can participate. The reward strategies are often accompanied by publicity programmes. Two such hypothetical strategies were presented to participants in a survey conducted amongst small business owners in Ekurhuleni, South Africa, to gauge their responses.
- Full Text:
- Date Issued: 2015
Educators and learners perceptions on english first additional language speakers use of english as medium of instruction
- Authors: Nqoma, Lungiswa
- Date: 2015
- Subjects: English language -- Study and teaching , English language
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24934 , vital:63678
- Description: This study investigates Educators‟ and learners‟ perceptions on English first additional language speakers‟ use of English as medium of instruction in two primary schools in the East London District. The study made use of a qualitative research method which includes interviews, observation and document analysis (learners‟ books). The uncovered data is analyzed against the background of the socio-economic and historical factors that led to this medium of instruction using content analysis (CA). After the apartheid regime in 1994 and the formation of a new government in 1996, the South African Constitution declared 11 languages in an attempt to encourage multilingualism in the country with each province having its provincial language policy. In the Eastern Cape where the study is conducted the language policy recognizes Xhosa, English, and Afrikaans as the official languages with English as the medium of instruction especially at the intermediate phase. The theoretical and conceptual framework for the study is provided by studies on language policy and planning, English as an international language, and Language as a mediating tool. The findings of the study indicate the crucial role that language of instruction plays in teaching and learning. However, challenges arise when the language of instruction is not the mother tongue. The study indicates dissatisfaction in the use of EMOI as a result of inadequate proficiency in the language of instruction, school environment, lack of resources; and lack of parental support. As a result of the above, some educators resorted to code switching when teaching. Hence, the study sheds light on EFAL learner‟s perspective on both comprehension and the level of educator‟s English skills and whether there is a connection between these two aspects. This resulted to conceivable methods that could be used to improve learner performance, teaching and learning methods and the efficiency of East London District support system. , Thesis (MEd) -- Faculty of Education, 2015
- Full Text:
- Date Issued: 2015
- Authors: Nqoma, Lungiswa
- Date: 2015
- Subjects: English language -- Study and teaching , English language
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24934 , vital:63678
- Description: This study investigates Educators‟ and learners‟ perceptions on English first additional language speakers‟ use of English as medium of instruction in two primary schools in the East London District. The study made use of a qualitative research method which includes interviews, observation and document analysis (learners‟ books). The uncovered data is analyzed against the background of the socio-economic and historical factors that led to this medium of instruction using content analysis (CA). After the apartheid regime in 1994 and the formation of a new government in 1996, the South African Constitution declared 11 languages in an attempt to encourage multilingualism in the country with each province having its provincial language policy. In the Eastern Cape where the study is conducted the language policy recognizes Xhosa, English, and Afrikaans as the official languages with English as the medium of instruction especially at the intermediate phase. The theoretical and conceptual framework for the study is provided by studies on language policy and planning, English as an international language, and Language as a mediating tool. The findings of the study indicate the crucial role that language of instruction plays in teaching and learning. However, challenges arise when the language of instruction is not the mother tongue. The study indicates dissatisfaction in the use of EMOI as a result of inadequate proficiency in the language of instruction, school environment, lack of resources; and lack of parental support. As a result of the above, some educators resorted to code switching when teaching. Hence, the study sheds light on EFAL learner‟s perspective on both comprehension and the level of educator‟s English skills and whether there is a connection between these two aspects. This resulted to conceivable methods that could be used to improve learner performance, teaching and learning methods and the efficiency of East London District support system. , Thesis (MEd) -- Faculty of Education, 2015
- Full Text:
- Date Issued: 2015
A multiscale remote sensing assessment of subtropical indigenous forests along the wild coast, South Africa
- Authors: Blessing, Sithole Vhusomuzi
- Date: 2015
- Subjects: Forests and forestry -- South Africa -- Remote sensing , Forest conservation , Remote sensing , Geographic information systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10677 , http://hdl.handle.net/10948/d1021169
- Description: The subtropical forests located along South Africa’s Wild Coast region, declared as one of the biodiversity hotspots, provide benefits to the local and national economy. However, there is evidence of increased pressure exerted on the forests by growing population and reduced income from activities not related to forest products. The ability of remote sensing to quantify subtropical forest changes over time, perform species discrimination (using field spectroscopy) and integrating field spectral and multispectral data were all assessed in this study. Investigations were conducted at pixel, leaf and sub-pixel levels. Both per-pixel and sub-pixel classification methods were used for improved forest characterisation. Using SPOT 6 imagery for 2013, the study determined the best classification algorithm for mapping sub-tropical forest and other land cover types to be the maximum likelihood classifier. Maximum likelihood outperformed minimum distance, spectral angle mapper and spectral information divergence algorithms, based on overall accuracy and Kappa coefficient values. Forest change analysis was made based on spectral measurements made at top of the atmosphere (TOC) level. When applied to the 2005 and 2009 SPOT 5 images, subtropical forest changes between 2005-2009 and 2009-2013 were quantified. A temporal analysis of forest cover trends in the periods 2005-2009 and 2009-2013 identified a decreasing trend of -3648.42 and -946.98 ha respectively, which translated to 7.81 percent and 2.20 percent decrease. Although there is evidence of a trend towards decreased rates of forest loss, more conservation efforts are required to protect the Wild Coast ecosystem. Using field spectral measurements data, the hierarchical method (comprising One-way ANOVA with Bonferroni correction, Classification and Regression Trees (CART) and Jeffries Matusita method) successfully selected optimal wavelengths for species discrimination at leaf level. Only 17 out of 2150 wavelengths were identified, thereby reducing the complexities related to data dimensionality. The optimal 17 wavelength bands were noted in the visible (438, 442, 512 and 695 nm), near infrared (724, 729, 750, 758, 856, 936, 1179, 1507 and 1673 nm) and mid-infrared (2220, 2465, 2469 and 2482 nm) portions of the electromagnetic spectrum. The Jeffries-Matusita (JM) distance method confirmed the separability of the selected wavelength bands. Using these 17 wavelengths, linear discriminant analysis (LDA) classified subtropical species at leaf level more accurately than partial least squares discriminant analysis (PLSDA) and random forest (RF). In addition, the study integrated field-collected canopy spectral and multispectral data to discriminate proportions of semi-deciduous and evergreen subtropical forests at sub-pixel level. By using the 2013 land cover (using MLC) to mask non-forested portions before sub-pixel classification (using MTMF), the proportional maps were a product of two classifiers. The proportional maps show higher proportions of evergreen forests along the coast while semi-deciduous subtropical forest species were mainly on inland parts of the Wild Coast. These maps had high accuracy, thereby proving the ability of an integration of field spectral and multispectral data in mapping semi-deciduous and evergreen forest species. Overall, the study has demonstrated the importance of the MLC and LDA and served to integrate field spectral and multispectral data in subtropical forest characterisation at both leaf and top-of-atmosphere levels. The success of both the MLC and LDA further highlighted how essential parametric classifiers are in remote sensing forestry applications. Main subtropical characteristics highlighted in this study were species discrimination at leaf level, quantifying forest change at pixel level and discriminating semi-deciduous and evergreen forests at sub-pixel level.
- Full Text:
- Date Issued: 2015
- Authors: Blessing, Sithole Vhusomuzi
- Date: 2015
- Subjects: Forests and forestry -- South Africa -- Remote sensing , Forest conservation , Remote sensing , Geographic information systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10677 , http://hdl.handle.net/10948/d1021169
- Description: The subtropical forests located along South Africa’s Wild Coast region, declared as one of the biodiversity hotspots, provide benefits to the local and national economy. However, there is evidence of increased pressure exerted on the forests by growing population and reduced income from activities not related to forest products. The ability of remote sensing to quantify subtropical forest changes over time, perform species discrimination (using field spectroscopy) and integrating field spectral and multispectral data were all assessed in this study. Investigations were conducted at pixel, leaf and sub-pixel levels. Both per-pixel and sub-pixel classification methods were used for improved forest characterisation. Using SPOT 6 imagery for 2013, the study determined the best classification algorithm for mapping sub-tropical forest and other land cover types to be the maximum likelihood classifier. Maximum likelihood outperformed minimum distance, spectral angle mapper and spectral information divergence algorithms, based on overall accuracy and Kappa coefficient values. Forest change analysis was made based on spectral measurements made at top of the atmosphere (TOC) level. When applied to the 2005 and 2009 SPOT 5 images, subtropical forest changes between 2005-2009 and 2009-2013 were quantified. A temporal analysis of forest cover trends in the periods 2005-2009 and 2009-2013 identified a decreasing trend of -3648.42 and -946.98 ha respectively, which translated to 7.81 percent and 2.20 percent decrease. Although there is evidence of a trend towards decreased rates of forest loss, more conservation efforts are required to protect the Wild Coast ecosystem. Using field spectral measurements data, the hierarchical method (comprising One-way ANOVA with Bonferroni correction, Classification and Regression Trees (CART) and Jeffries Matusita method) successfully selected optimal wavelengths for species discrimination at leaf level. Only 17 out of 2150 wavelengths were identified, thereby reducing the complexities related to data dimensionality. The optimal 17 wavelength bands were noted in the visible (438, 442, 512 and 695 nm), near infrared (724, 729, 750, 758, 856, 936, 1179, 1507 and 1673 nm) and mid-infrared (2220, 2465, 2469 and 2482 nm) portions of the electromagnetic spectrum. The Jeffries-Matusita (JM) distance method confirmed the separability of the selected wavelength bands. Using these 17 wavelengths, linear discriminant analysis (LDA) classified subtropical species at leaf level more accurately than partial least squares discriminant analysis (PLSDA) and random forest (RF). In addition, the study integrated field-collected canopy spectral and multispectral data to discriminate proportions of semi-deciduous and evergreen subtropical forests at sub-pixel level. By using the 2013 land cover (using MLC) to mask non-forested portions before sub-pixel classification (using MTMF), the proportional maps were a product of two classifiers. The proportional maps show higher proportions of evergreen forests along the coast while semi-deciduous subtropical forest species were mainly on inland parts of the Wild Coast. These maps had high accuracy, thereby proving the ability of an integration of field spectral and multispectral data in mapping semi-deciduous and evergreen forest species. Overall, the study has demonstrated the importance of the MLC and LDA and served to integrate field spectral and multispectral data in subtropical forest characterisation at both leaf and top-of-atmosphere levels. The success of both the MLC and LDA further highlighted how essential parametric classifiers are in remote sensing forestry applications. Main subtropical characteristics highlighted in this study were species discrimination at leaf level, quantifying forest change at pixel level and discriminating semi-deciduous and evergreen forests at sub-pixel level.
- Full Text:
- Date Issued: 2015
Optical properties of water-soluble L-cysteine-capped alloyed CdSeS quantum dot passivated with ZnSeTe and ZnSeTe/ZnS shells
- Adegoke, Oluwasesan, Nyokong, Tebello, Forbes, Patricia B C
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193609 , vital:45352 , xlink:href="https://doi.org/10.1016/j.optmat.2015.05.024"
- Description: Alloyed quantum dots (QDs) passivated with shell materials have valuable optical characteristics suitable for a wide array of applications. In this work, alloyed ternary CdSeS QDs passivated with ZnSeTe and ZnSeTe/ZnS shells have been synthesized via a hot-injection method and a ligand exchange reaction employing L-cysteine as a thiol ligand has been used to obtain these water-soluble nanocrystals for the first time. The photoluminescence (PL) quantum yield (QY) of alloyed L-cysteine-capped CdSeS was 71.2% but decreased significantly to 5.2% upon passivation with a ZnSeTe shell. The red shift in PL emission of the CdSeS/ZnSeTe QDs was attributed to be strain-induced whilst a lattice-induced process likely created defect states in the core/shell interface hence contributing to the decline in the PL QY. Nonetheless, the fluorescence stability of CdSeS/ZnSeTe QDs in aqueous solution was unperturbed. Further passivation with a ZnS shell (CdSeS/ZnSeTe/ZnS) improved the PL QY to a value of 58.7% and thus indicates that the defect state in the QDs core/shell/shell structure was reduced. PL lifetime exciton measurements indicated that the rates of decay of the QDs influenced their photophysical properties.
- Full Text:
- Date Issued: 2015
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193609 , vital:45352 , xlink:href="https://doi.org/10.1016/j.optmat.2015.05.024"
- Description: Alloyed quantum dots (QDs) passivated with shell materials have valuable optical characteristics suitable for a wide array of applications. In this work, alloyed ternary CdSeS QDs passivated with ZnSeTe and ZnSeTe/ZnS shells have been synthesized via a hot-injection method and a ligand exchange reaction employing L-cysteine as a thiol ligand has been used to obtain these water-soluble nanocrystals for the first time. The photoluminescence (PL) quantum yield (QY) of alloyed L-cysteine-capped CdSeS was 71.2% but decreased significantly to 5.2% upon passivation with a ZnSeTe shell. The red shift in PL emission of the CdSeS/ZnSeTe QDs was attributed to be strain-induced whilst a lattice-induced process likely created defect states in the core/shell interface hence contributing to the decline in the PL QY. Nonetheless, the fluorescence stability of CdSeS/ZnSeTe QDs in aqueous solution was unperturbed. Further passivation with a ZnS shell (CdSeS/ZnSeTe/ZnS) improved the PL QY to a value of 58.7% and thus indicates that the defect state in the QDs core/shell/shell structure was reduced. PL lifetime exciton measurements indicated that the rates of decay of the QDs influenced their photophysical properties.
- Full Text:
- Date Issued: 2015
Teaching for conceptual understanding : an analysis of selected teachers' practice
- Authors: Kashima, Andreas Akwenye
- Date: 2015
- Subjects: Teacher effectiveness -- Namibia , Student-centered learning -- Namibia , Constructivism (Education) -- Namibia , Problem solving , Teachers -- In-service training -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2037 , http://hdl.handle.net/10962/d1017348
- Description: The purpose of this study was to explore how teachers’ practice either supports or constrains learners’ conceptual understanding. The study is structured within an interpretive paradigm. The research takes the form of a case study and focused on the teaching practice of two purposefully selected teachers who had been identified as being effective/successful practitioners. The data was collected in two stages. In the first stage, qualitative data was collected by video recording six classroom lessons, three for each of the two participating teachers. In stage 2, participating teachers were individually interviewed. In these interviews the two participating teachers were asked to reflect on their classroom practice, through a process of stimulated recall, where their actions seemed to either support or constrain the development of learners’ conceptual understanding. The study identified a number of elements of the two teachers’ practice that related to the development of learners’ conceptual understanding in the classroom. These include building on learners’ prior knowledge, the use of concrete manipulatives, questioning that promotes critical thinking, and the use of multiple representations and connections. The study also identified elements of the two teachers’ practice that had the potential to constrain the development of learners’ conceptual understanding. These include the lack of opportunities for co-operative or peer-oriented learning, the absence of questioning that leads to discussion, and a scarcity of activities that build mathematical concepts through hands-on engagement. The study highlights the need for supporting teachers and helping them strengthen their practice with regard to those activities that support the development of conceptual understanding in their learners.
- Full Text:
- Date Issued: 2015
- Authors: Kashima, Andreas Akwenye
- Date: 2015
- Subjects: Teacher effectiveness -- Namibia , Student-centered learning -- Namibia , Constructivism (Education) -- Namibia , Problem solving , Teachers -- In-service training -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2037 , http://hdl.handle.net/10962/d1017348
- Description: The purpose of this study was to explore how teachers’ practice either supports or constrains learners’ conceptual understanding. The study is structured within an interpretive paradigm. The research takes the form of a case study and focused on the teaching practice of two purposefully selected teachers who had been identified as being effective/successful practitioners. The data was collected in two stages. In the first stage, qualitative data was collected by video recording six classroom lessons, three for each of the two participating teachers. In stage 2, participating teachers were individually interviewed. In these interviews the two participating teachers were asked to reflect on their classroom practice, through a process of stimulated recall, where their actions seemed to either support or constrain the development of learners’ conceptual understanding. The study identified a number of elements of the two teachers’ practice that related to the development of learners’ conceptual understanding in the classroom. These include building on learners’ prior knowledge, the use of concrete manipulatives, questioning that promotes critical thinking, and the use of multiple representations and connections. The study also identified elements of the two teachers’ practice that had the potential to constrain the development of learners’ conceptual understanding. These include the lack of opportunities for co-operative or peer-oriented learning, the absence of questioning that leads to discussion, and a scarcity of activities that build mathematical concepts through hands-on engagement. The study highlights the need for supporting teachers and helping them strengthen their practice with regard to those activities that support the development of conceptual understanding in their learners.
- Full Text:
- Date Issued: 2015
Characterization of the co-chaperones of Hsp70 and Hsp90 in Trypanosoma brucei and their potential partnerships
- Authors: Mokoena, Fortunate
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54543 , vital:26583
- Description: African Trypanosomiasis, which is caused by Trypanosoma brucei, is one of the crippling agents of social and economic development in Africa. T. brucei cycles between the cold-blooded insect vector, the tsetse fly (Glossina spp), and warm-blooded mammalian hosts. T. brucei, T. cruzi and L. major are mammal infecting kinetoplastid parasites that are collectively referred to as TriTryps. These parasites experience extreme environments as they move between their warm-blooded mammalian hosts and cold-blooded insect vectors which trigger extensive morphological transformations during the life-cycle of the parasite. Molecular chaperones have been implicated in parasite differentiation. TriTryps display significant expansions and diversity in the gene complements encoding molecular chaperones, especially J-proteins. Generally, J-proteins function as co-chaperones of Hsp70s, forming part of vital protein homeostasis processes. Hsp70s show a high degree of conservation, while J-proteins appear to be an extreme case of taxonomic radiation. Although several studies have focused on the molecular and cell biology of Hsp70s in some kinetoplastid parasites, knowledge is still lacking pertaining to J-proteins and their partnerships with Hsp70s. This thesis focused on the classification of kinetoplastid Jproteins into the four types by examining the domain organizations using T. brucei as a guide. The potential partnership of J-proteins and Hsp70s were postulated based on predicted subcellular localization. Kinetoplastid parasites, particularly T. brucei, have evolved an expanded and specialized J-protein machinery, likely to be a consequence of an evolutionary fitness/trait to adapt to diverse environment present in hosts and vectors. These analyses will yield insight into the process of parasite differentiation as well as provide new leads for chemotherapeutic treatments. The presence of the STI1 mediated Hsp90 hetero-complex formation has not been confirmed in T. brucei. To this end, in silico and biochemical techniques were used to characterize the role of TbSTI1, as an adaptor protein of Hsp70 and Hsp90. Through domain architecture analysis, sequence alignments, phylogenetic analysis and three-dimensional structure prediction, TbSTI1 was demonstrated to be the most conserved TPR containing co-chaperone of Hsp70 and Hsp83 in T. brucei and also shown to be highly similar to its eukaryotic homologues. Recombinant TbSTI1 was overproduced and purified in E.coli cells and subsequently shown to associate with TcHsp70 in a concentration dependent manner and associate weakly with TbHsp70.4. TbSTI1 and TbHsp83 were also demonstrated to be expressed and upregulated upon exposure to heat shock at the bloodstream stage of parasite development. In conclusion, this study is the first to report the interaction of TbSTI1 with a chaperone. Interactions between TbSTI1 and Hsp70s were demonstrated and therefore, the formation of the hetero-complex is predicted based the similarity of TbSTI1 to other STI1 proteins.
- Full Text:
- Date Issued: 2015
- Authors: Mokoena, Fortunate
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54543 , vital:26583
- Description: African Trypanosomiasis, which is caused by Trypanosoma brucei, is one of the crippling agents of social and economic development in Africa. T. brucei cycles between the cold-blooded insect vector, the tsetse fly (Glossina spp), and warm-blooded mammalian hosts. T. brucei, T. cruzi and L. major are mammal infecting kinetoplastid parasites that are collectively referred to as TriTryps. These parasites experience extreme environments as they move between their warm-blooded mammalian hosts and cold-blooded insect vectors which trigger extensive morphological transformations during the life-cycle of the parasite. Molecular chaperones have been implicated in parasite differentiation. TriTryps display significant expansions and diversity in the gene complements encoding molecular chaperones, especially J-proteins. Generally, J-proteins function as co-chaperones of Hsp70s, forming part of vital protein homeostasis processes. Hsp70s show a high degree of conservation, while J-proteins appear to be an extreme case of taxonomic radiation. Although several studies have focused on the molecular and cell biology of Hsp70s in some kinetoplastid parasites, knowledge is still lacking pertaining to J-proteins and their partnerships with Hsp70s. This thesis focused on the classification of kinetoplastid Jproteins into the four types by examining the domain organizations using T. brucei as a guide. The potential partnership of J-proteins and Hsp70s were postulated based on predicted subcellular localization. Kinetoplastid parasites, particularly T. brucei, have evolved an expanded and specialized J-protein machinery, likely to be a consequence of an evolutionary fitness/trait to adapt to diverse environment present in hosts and vectors. These analyses will yield insight into the process of parasite differentiation as well as provide new leads for chemotherapeutic treatments. The presence of the STI1 mediated Hsp90 hetero-complex formation has not been confirmed in T. brucei. To this end, in silico and biochemical techniques were used to characterize the role of TbSTI1, as an adaptor protein of Hsp70 and Hsp90. Through domain architecture analysis, sequence alignments, phylogenetic analysis and three-dimensional structure prediction, TbSTI1 was demonstrated to be the most conserved TPR containing co-chaperone of Hsp70 and Hsp83 in T. brucei and also shown to be highly similar to its eukaryotic homologues. Recombinant TbSTI1 was overproduced and purified in E.coli cells and subsequently shown to associate with TcHsp70 in a concentration dependent manner and associate weakly with TbHsp70.4. TbSTI1 and TbHsp83 were also demonstrated to be expressed and upregulated upon exposure to heat shock at the bloodstream stage of parasite development. In conclusion, this study is the first to report the interaction of TbSTI1 with a chaperone. Interactions between TbSTI1 and Hsp70s were demonstrated and therefore, the formation of the hetero-complex is predicted based the similarity of TbSTI1 to other STI1 proteins.
- Full Text:
- Date Issued: 2015
Managing conflict in the library information services of selected universities
- Authors: Dos Santos, Desiree
- Date: 2015
- Subjects: Conflict management -- South Africa -- Eastern Cape , Academic libraries -- South Africa -- Eastern Cape -- Administration , Technology -- South Africa -- Eastern Cape -- Information services , Academic librarians -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: vital:8325 , http://hdl.handle.net/10948/d1020307
- Description: Academic libraries are not immune to conflict; various important external and internal factors underlie conflict. Change, both external and internal, leads to interpersonal conflict amongst librarians which is caused by differing goals, policies, rules and decisions. Technology has been the major change in the digital era and academic libraries embarking on meeting the needs of the users have to manage change. It is important to understand how change evolves in order to manage it and the faster the change, the more conflict can be expected. The main purpose of this study is to investigate change and conflict in library and information services. The study collected data from two selected academic libraries - Fort Hare and Walter Sisulu. The reason for this choice is that the two libraries are from the Eastern Border region and strategically located to serve the deep rural and poverty-stricken communities. Both libraries are from merged institutions, under-developed and faced with change and conflict. Data was gathered by means of a literature study and face-to-face, semi-structured interviews with six participants in each library: two librarians in senior, two middle management and two librarians occupying lower level positions. Purposive sampling was used to select participants who fit the criteria and who could contribute to the study. The findings reveal that library staff experience stress and conflict because of external and internal factors of change impacting the academic environment. The study generated important findings which are capable of guiding academic library management on how to manage change effectively in the „new‟ electronic environment. The findings show that understanding conflict also equips management with strategies and techniques to manage conflict effectively. This study offers valuable insights into the lived conflict experiences and perceptions of librarians and sheds much light on the role of conflict management in these environments. This study will contribute to the management of conflict in information services in university libraries and will be an innovative application of conflict theory to the library discipline.
- Full Text:
- Date Issued: 2015
- Authors: Dos Santos, Desiree
- Date: 2015
- Subjects: Conflict management -- South Africa -- Eastern Cape , Academic libraries -- South Africa -- Eastern Cape -- Administration , Technology -- South Africa -- Eastern Cape -- Information services , Academic librarians -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: vital:8325 , http://hdl.handle.net/10948/d1020307
- Description: Academic libraries are not immune to conflict; various important external and internal factors underlie conflict. Change, both external and internal, leads to interpersonal conflict amongst librarians which is caused by differing goals, policies, rules and decisions. Technology has been the major change in the digital era and academic libraries embarking on meeting the needs of the users have to manage change. It is important to understand how change evolves in order to manage it and the faster the change, the more conflict can be expected. The main purpose of this study is to investigate change and conflict in library and information services. The study collected data from two selected academic libraries - Fort Hare and Walter Sisulu. The reason for this choice is that the two libraries are from the Eastern Border region and strategically located to serve the deep rural and poverty-stricken communities. Both libraries are from merged institutions, under-developed and faced with change and conflict. Data was gathered by means of a literature study and face-to-face, semi-structured interviews with six participants in each library: two librarians in senior, two middle management and two librarians occupying lower level positions. Purposive sampling was used to select participants who fit the criteria and who could contribute to the study. The findings reveal that library staff experience stress and conflict because of external and internal factors of change impacting the academic environment. The study generated important findings which are capable of guiding academic library management on how to manage change effectively in the „new‟ electronic environment. The findings show that understanding conflict also equips management with strategies and techniques to manage conflict effectively. This study offers valuable insights into the lived conflict experiences and perceptions of librarians and sheds much light on the role of conflict management in these environments. This study will contribute to the management of conflict in information services in university libraries and will be an innovative application of conflict theory to the library discipline.
- Full Text:
- Date Issued: 2015
Evaluation of knowledge and practices of nurses with regard to prevention of nosocomial infection in the intensive care units of Eastern Cape Province
- Mlenzana, Nosiphiwo Priscilla
- Authors: Mlenzana, Nosiphiwo Priscilla
- Date: 2015
- Subjects: Nosocomial infections http://id.loc.gov/authorities/subjects/sh85092770 , Cross infection--Prevention http://id.loc.gov/authorities/subjects/sh2009122612 , Infection http://id.loc.gov/authorities/subjects/sh85066076
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19639 , vital:43154
- Description: Aim: To determine the level of knowledge and practice of the nurses in the prevention and control of nosocomial infection in the intensive care units and make recommendations aiming at bridging the gap identified. In this study, the level of knowledge and practice of nurses in the intensive care units was described and its relationship with the demographic characteristics was examined utilising a quantitative approach. A quantitative descriptive design was used to examine and describe knowledge and practices of intensive care nurses with regards to prevention and control of nosocomial infection. One hundred and thirty (130) nurses participated in the study taken from the intensive care units of the five (5) state hospitals of the Eastern Cape Province. A self-designed questionnaire with close-ended questions was utilised comprising of dichotomous questions, with ‘yes’ or ‘no’ measuring knowledge nurses have and a Likert scale that measured knowledge with regards to clinical practice utilised in the prevention and control of nosocomial infections. The following ethical considerations were addressed by the study: ethical clearance, permission to conduct the study, informed consent from participants, anonymity and confidentiality and respect of individual autonomy. Findings: The respondents showed encouraging agreement with the different practices that should be followed in order to prevent spreading of nosocomial infections in their units. This knowledge suggests that the problem of infection control in ICUs may be related to the individual characteristics of the profession as opposed to being institutional. Limitations: Not all the intensive care units of the Eastern Cape hospitals were included due to challenges of time, finance and geographic factors. Recommendations: The following recommendations were made: Orientation programme to all new staff coming into the ICUs including infection control policies and guidelines; Involvement of the ICU staff in the development of infection control policies so as to ensure ownership and ultimate compliance; The employer must ensure that all resources for infection control and prevention are available and accessible to the health care workers at all times to ensure compliance. , Thesis (MCur) -- University of Fort Hare, 2015
- Full Text:
- Date Issued: 2015
- Authors: Mlenzana, Nosiphiwo Priscilla
- Date: 2015
- Subjects: Nosocomial infections http://id.loc.gov/authorities/subjects/sh85092770 , Cross infection--Prevention http://id.loc.gov/authorities/subjects/sh2009122612 , Infection http://id.loc.gov/authorities/subjects/sh85066076
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19639 , vital:43154
- Description: Aim: To determine the level of knowledge and practice of the nurses in the prevention and control of nosocomial infection in the intensive care units and make recommendations aiming at bridging the gap identified. In this study, the level of knowledge and practice of nurses in the intensive care units was described and its relationship with the demographic characteristics was examined utilising a quantitative approach. A quantitative descriptive design was used to examine and describe knowledge and practices of intensive care nurses with regards to prevention and control of nosocomial infection. One hundred and thirty (130) nurses participated in the study taken from the intensive care units of the five (5) state hospitals of the Eastern Cape Province. A self-designed questionnaire with close-ended questions was utilised comprising of dichotomous questions, with ‘yes’ or ‘no’ measuring knowledge nurses have and a Likert scale that measured knowledge with regards to clinical practice utilised in the prevention and control of nosocomial infections. The following ethical considerations were addressed by the study: ethical clearance, permission to conduct the study, informed consent from participants, anonymity and confidentiality and respect of individual autonomy. Findings: The respondents showed encouraging agreement with the different practices that should be followed in order to prevent spreading of nosocomial infections in their units. This knowledge suggests that the problem of infection control in ICUs may be related to the individual characteristics of the profession as opposed to being institutional. Limitations: Not all the intensive care units of the Eastern Cape hospitals were included due to challenges of time, finance and geographic factors. Recommendations: The following recommendations were made: Orientation programme to all new staff coming into the ICUs including infection control policies and guidelines; Involvement of the ICU staff in the development of infection control policies so as to ensure ownership and ultimate compliance; The employer must ensure that all resources for infection control and prevention are available and accessible to the health care workers at all times to ensure compliance. , Thesis (MCur) -- University of Fort Hare, 2015
- Full Text:
- Date Issued: 2015
Factors influencing consumer decision-making process in the private health institutions
- Authors: Akponah, Voke Blessing
- Date: 2015
- Subjects: Consumer behavior Decision making , Public-private sector cooperation
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/50033 , vital:41993
- Description: The development that has taken place in the health care sector includes all factors that have brought changes in the consumer decision-making process regarding the private health institutions. In Nigeria, the development is evident in the delivery of the health care services. This indicates that the private health institutions deliver quality health care service by using efficient and quality medical equipment. However, there is a growing awareness among clients to perform an extensive search before the purchase of health care service and the increased expectation from health care quality by clients and their family. The change in consumer behaviour has caused a shift in the consumer decision-making process due to the availability of several sources of information and various health institutions they can choose from. The purpose of this study is to investigate the factors that influence the consumer decision-making process that can enhance customer satisfaction and reduce cognitive dissonance. In this study the behaviour of consumers is related to how they make decisions along several stages before they make a purchase and in a health care setting the decision-making process refers to the process that clients pass through in making choices on alternative health institutions. The quantitative research method was adopted in this study in describing, analysing and interpreting data. A structured questionnaire was employed to collect primary data from 450 respondents in Lagos state, Nigeria. The primary data was statistically analysed using five stages, namely, exploratory factor analysis, Cronbach‟s alpha reliability testing, descriptive statistics, multiple regression analysis, and Pearson correlation analysis. The empirical results of this study indicates that service encounter experience, personal income and support sources are significantly related to the decision-making process. The decision-making process also has significant positive relationship with both customer satisfaction and cognitive dissonance. This indicates that influential factors that have been identified through the empirical results enlighten researchers and the private health institutions on issues that influence the clients‟ decisions to utilise private health institutions. The well-being and satisfaction of clients will be enhanced if the private health institutions can craft effective strategies that will enable clients to gain easy access and utilise health care services. This study emphasised that access to and utilisation of health care services in the private health institutions can be granted to clients through personal income and support sources from family members and private health institutions. Futhermore, health insurance coverage is an effective way that will help clients overcome the financial constraints and restricted access to and utilisation of private health institutions. The study further reveals that the well-being and satisfaction of clients will be enhanced if private health institutions improve access to quality health care. Failure to improve the overall quality and performances of the health care services in the private health institutions can lead to clients‟ cognitive dissonance. Both private and public health institutions should play a major role in providing the necessary facilities that can assist the clients in their decision-making process regarding their health care needs. This will enable the health care institutions‟ staff to understand what clients value and need and, therefore, how well to satisfy them and reduce cognitive dissonance. Easy access and utilisation of the private health institutions as well as satisfaction in quality health care delivery will create better health outcomes for the workforce and citizens of a country and this will improve economic development.
- Full Text:
- Date Issued: 2015
- Authors: Akponah, Voke Blessing
- Date: 2015
- Subjects: Consumer behavior Decision making , Public-private sector cooperation
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/50033 , vital:41993
- Description: The development that has taken place in the health care sector includes all factors that have brought changes in the consumer decision-making process regarding the private health institutions. In Nigeria, the development is evident in the delivery of the health care services. This indicates that the private health institutions deliver quality health care service by using efficient and quality medical equipment. However, there is a growing awareness among clients to perform an extensive search before the purchase of health care service and the increased expectation from health care quality by clients and their family. The change in consumer behaviour has caused a shift in the consumer decision-making process due to the availability of several sources of information and various health institutions they can choose from. The purpose of this study is to investigate the factors that influence the consumer decision-making process that can enhance customer satisfaction and reduce cognitive dissonance. In this study the behaviour of consumers is related to how they make decisions along several stages before they make a purchase and in a health care setting the decision-making process refers to the process that clients pass through in making choices on alternative health institutions. The quantitative research method was adopted in this study in describing, analysing and interpreting data. A structured questionnaire was employed to collect primary data from 450 respondents in Lagos state, Nigeria. The primary data was statistically analysed using five stages, namely, exploratory factor analysis, Cronbach‟s alpha reliability testing, descriptive statistics, multiple regression analysis, and Pearson correlation analysis. The empirical results of this study indicates that service encounter experience, personal income and support sources are significantly related to the decision-making process. The decision-making process also has significant positive relationship with both customer satisfaction and cognitive dissonance. This indicates that influential factors that have been identified through the empirical results enlighten researchers and the private health institutions on issues that influence the clients‟ decisions to utilise private health institutions. The well-being and satisfaction of clients will be enhanced if the private health institutions can craft effective strategies that will enable clients to gain easy access and utilise health care services. This study emphasised that access to and utilisation of health care services in the private health institutions can be granted to clients through personal income and support sources from family members and private health institutions. Futhermore, health insurance coverage is an effective way that will help clients overcome the financial constraints and restricted access to and utilisation of private health institutions. The study further reveals that the well-being and satisfaction of clients will be enhanced if private health institutions improve access to quality health care. Failure to improve the overall quality and performances of the health care services in the private health institutions can lead to clients‟ cognitive dissonance. Both private and public health institutions should play a major role in providing the necessary facilities that can assist the clients in their decision-making process regarding their health care needs. This will enable the health care institutions‟ staff to understand what clients value and need and, therefore, how well to satisfy them and reduce cognitive dissonance. Easy access and utilisation of the private health institutions as well as satisfaction in quality health care delivery will create better health outcomes for the workforce and citizens of a country and this will improve economic development.
- Full Text:
- Date Issued: 2015
Phytochemical, antibacterial and pharmacological investigations of Clausena Anisata (Wild). Hook : bone of the medicinal plants used for traditional treatment of "tuberculosis" in Eastern Cape, South Africa
- Authors: Lawal, Ibraheem O
- Date: 2015
- Subjects: Traditional medicine--South Africa--Eastern Cape Tuberculosis--Treatment--South Africa--Eastern Cape Mycobacterial diseases--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Ethnobotany
- Identifier: http://hdl.handle.net/10353/11828 , vital:39110
- Description: Clausena anisata (Willd) Hook, is the only species out of the 15 species of the genus found in the African continent and is regarded as a threatened species in this area of Southern region of Africa. Its distribution spread across Africa to south-east Asia. C. anisata has a wide range of ethno-pharmacological importance. Despite the numerous studies on the pharmacological profile of the plant, there is still dearth of scientific literature on the foliar micro-morphology of this valuable medicinal plant. The morphorlogical structure of the leaves of C. anisata was examined under Light Microscopy (LM), Scanning Electron Microscopy (SEM) and Energy Dispersive x-ray Spectroscopy (EDS) following standard procedures. LM indicates the types of stomata of the leaves (amphistomatic). SEM revealed the presence of the whip like trichomes with its uniqueness to the plants. EDS showed the chemical composition of the foliar appendages which indicated the presence Ca, Mg, S, and Fe. The indication of the elements could probably be helpful in the herbal drug regulation based on the mineral composition and in return reduced herbal drug toxicity.
- Full Text:
- Date Issued: 2015
- Authors: Lawal, Ibraheem O
- Date: 2015
- Subjects: Traditional medicine--South Africa--Eastern Cape Tuberculosis--Treatment--South Africa--Eastern Cape Mycobacterial diseases--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Ethnobotany
- Identifier: http://hdl.handle.net/10353/11828 , vital:39110
- Description: Clausena anisata (Willd) Hook, is the only species out of the 15 species of the genus found in the African continent and is regarded as a threatened species in this area of Southern region of Africa. Its distribution spread across Africa to south-east Asia. C. anisata has a wide range of ethno-pharmacological importance. Despite the numerous studies on the pharmacological profile of the plant, there is still dearth of scientific literature on the foliar micro-morphology of this valuable medicinal plant. The morphorlogical structure of the leaves of C. anisata was examined under Light Microscopy (LM), Scanning Electron Microscopy (SEM) and Energy Dispersive x-ray Spectroscopy (EDS) following standard procedures. LM indicates the types of stomata of the leaves (amphistomatic). SEM revealed the presence of the whip like trichomes with its uniqueness to the plants. EDS showed the chemical composition of the foliar appendages which indicated the presence Ca, Mg, S, and Fe. The indication of the elements could probably be helpful in the herbal drug regulation based on the mineral composition and in return reduced herbal drug toxicity.
- Full Text:
- Date Issued: 2015
An assessment of the in vitro neuroprotective potential of selected Algerian and South African medicinal plant extracts
- Authors: Fewell, William
- Date: 2015
- Subjects: Medicinal plants -- South Africa , Nervous system -- Alternative treatment -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/8608 , vital:26411
- Description: It is estimated by the World Health Organization (WHO) that by 2040 neurodegenerative disorders will collectively surpass cancer as the primary cause of death in industrialised countries (WHO,2006). Natural flora represents one of the most important therapeutic sources in modern drug discovery, however only a limited number of plant species have been screened for their neuroprotective value. The neuroprotective potential of eleven Algerian and two South African medicinal plant extracts were assessed in this study, aiming to identify promising candidates for future research. Neurodegenerative disorders such as Parkinson’s disease are characterised by distinct biochemical features, including protein misfolding/-aggregation, excessive oxidative stress and apoptotic cell death. As such, medicinal plant extracts were screened for biological properties directly relevant to neurodegeneration. The capacity to induce autophagy was also investigated as mounting evidence suggests that activation of this pathway may reduce abnormal protein aggregation and promote neuronal survival.
- Full Text: false
- Date Issued: 2015
- Authors: Fewell, William
- Date: 2015
- Subjects: Medicinal plants -- South Africa , Nervous system -- Alternative treatment -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/8608 , vital:26411
- Description: It is estimated by the World Health Organization (WHO) that by 2040 neurodegenerative disorders will collectively surpass cancer as the primary cause of death in industrialised countries (WHO,2006). Natural flora represents one of the most important therapeutic sources in modern drug discovery, however only a limited number of plant species have been screened for their neuroprotective value. The neuroprotective potential of eleven Algerian and two South African medicinal plant extracts were assessed in this study, aiming to identify promising candidates for future research. Neurodegenerative disorders such as Parkinson’s disease are characterised by distinct biochemical features, including protein misfolding/-aggregation, excessive oxidative stress and apoptotic cell death. As such, medicinal plant extracts were screened for biological properties directly relevant to neurodegeneration. The capacity to induce autophagy was also investigated as mounting evidence suggests that activation of this pathway may reduce abnormal protein aggregation and promote neuronal survival.
- Full Text: false
- Date Issued: 2015
Through the Burtonesque looking-glass : interrogating the psychoanalytic in Tim Burton's adaptation of selected children's texts
- Authors: Van Zyl, Simone
- Date: 2015
- Subjects: Burton, Tim, -- 1958 Children's literature Psychoanalysis and literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10353/12304 , vital:39251
- Description: The primary aim of this thesis is to interrogate existing psychoanalytical theory, as well as to conduct research on ‘the Burtonesque’ in order to examine two of Tim Burton's filmic adaptations of classic literary works for children, namely: Alice in Wonderland (2010), an adaptation inspired by Lewis Carroll's Alice books, and Charlie and the Chocolate Factory (2005), based on Roald Dahl's novel of the same title. Firstly, the chapters will explore the psychological elements found in the original texts, which Burton amplifies in his onscreen adaptations by means of various stylistic and thematic techniques that have become known as ‘the Burtonesque’. Secondly, the ‘Burtonesque’ itself will be explored, and thirdly, by means of comparative analysis, the investigation will focus on the manner in which such aesthetics aid Burton in highlighting psychological concerns in his films, as well as interrogate his cinematic alterations to existing texts in order to further his purpose. As a keen enthusiast of psychology and having won awards within the field, Tim Burton, a foremost contemporary Hollywood filmmaker, in his adaptations of children’s classics, deliberately magnifies the psychoanalytic components that are often found in the tales. Through his unique interpretation, Burton brings the psychoanalytic approach to children’s stories to a new level. He explores certain themes such as death, childhood fantasies, psychological development and parental relationships, and makes use of specific artistic techniques that create a sense of the uncanny and defamiliarisation in the viewer. Due to his gothic cinematic approach, Burton is one of the most recognisable artists in his field, with a consistent vision that is concerned with cinematic and thematic aspects of his work, branding his films with a unique ‘Burtonesque’ quality that has become instantly identifiable. As a result of Burton’s psychological interest in children’s stories, Tim Burton’s film adaptations of the Dahl and Carroll classic children’s stories can be interrogated under a psychoanalytic lens. Psychoanalytic literary criticism is a method of literary analysis that is informed by the tradition of psychoanalysis established by Freud. In Burton scholarship, critical exploration should take the form of not only a close reading of the original text and analysis of the film version in order to come to a psychoanalytic interpretation, but by means of comparison of film and text, highlight the methods applied by psychoanalytic theory. A close comparative analysis of original literary works by Roald Dahl and Lewis Carroll, and Tim Burton’s filmic adaptations will be conducted in this study. Thereby, the manner in which Tim Burton employs specific techniques in order to emphasise the stories’ psychological components will be explored. Biographical information of Dahl and Lewis, as well as a short synopsis of their stories will be included in order to provide the context for psychoanalytical criticism. A discussion of ‘the Burtonesque’ will be provided, as well as a brief exploration of his adaptation history and Burton’s specific interest in psychology. Research methods to be applied in the analysis of the original texts and their film versions are psychoanalytic literary theory, drawing predominantly on the work of theorists: Sigmund Freud, Jacques Lacan and Carl Jung. A close examination of auteur theory, the unique voice Burton has established through his iconic cinematic techniques, now coined ‘the Burtonesque’, will also be applied to provide a fuller and rounder interrogation. The focus of this project is to investigate thempsychoanalytical elements found in the texts and films, in order to clearly illustrate how Tim Burton’s cinematic approach serves to highlight a psychoanalytic interpretation.
- Full Text:
- Date Issued: 2015
- Authors: Van Zyl, Simone
- Date: 2015
- Subjects: Burton, Tim, -- 1958 Children's literature Psychoanalysis and literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10353/12304 , vital:39251
- Description: The primary aim of this thesis is to interrogate existing psychoanalytical theory, as well as to conduct research on ‘the Burtonesque’ in order to examine two of Tim Burton's filmic adaptations of classic literary works for children, namely: Alice in Wonderland (2010), an adaptation inspired by Lewis Carroll's Alice books, and Charlie and the Chocolate Factory (2005), based on Roald Dahl's novel of the same title. Firstly, the chapters will explore the psychological elements found in the original texts, which Burton amplifies in his onscreen adaptations by means of various stylistic and thematic techniques that have become known as ‘the Burtonesque’. Secondly, the ‘Burtonesque’ itself will be explored, and thirdly, by means of comparative analysis, the investigation will focus on the manner in which such aesthetics aid Burton in highlighting psychological concerns in his films, as well as interrogate his cinematic alterations to existing texts in order to further his purpose. As a keen enthusiast of psychology and having won awards within the field, Tim Burton, a foremost contemporary Hollywood filmmaker, in his adaptations of children’s classics, deliberately magnifies the psychoanalytic components that are often found in the tales. Through his unique interpretation, Burton brings the psychoanalytic approach to children’s stories to a new level. He explores certain themes such as death, childhood fantasies, psychological development and parental relationships, and makes use of specific artistic techniques that create a sense of the uncanny and defamiliarisation in the viewer. Due to his gothic cinematic approach, Burton is one of the most recognisable artists in his field, with a consistent vision that is concerned with cinematic and thematic aspects of his work, branding his films with a unique ‘Burtonesque’ quality that has become instantly identifiable. As a result of Burton’s psychological interest in children’s stories, Tim Burton’s film adaptations of the Dahl and Carroll classic children’s stories can be interrogated under a psychoanalytic lens. Psychoanalytic literary criticism is a method of literary analysis that is informed by the tradition of psychoanalysis established by Freud. In Burton scholarship, critical exploration should take the form of not only a close reading of the original text and analysis of the film version in order to come to a psychoanalytic interpretation, but by means of comparison of film and text, highlight the methods applied by psychoanalytic theory. A close comparative analysis of original literary works by Roald Dahl and Lewis Carroll, and Tim Burton’s filmic adaptations will be conducted in this study. Thereby, the manner in which Tim Burton employs specific techniques in order to emphasise the stories’ psychological components will be explored. Biographical information of Dahl and Lewis, as well as a short synopsis of their stories will be included in order to provide the context for psychoanalytical criticism. A discussion of ‘the Burtonesque’ will be provided, as well as a brief exploration of his adaptation history and Burton’s specific interest in psychology. Research methods to be applied in the analysis of the original texts and their film versions are psychoanalytic literary theory, drawing predominantly on the work of theorists: Sigmund Freud, Jacques Lacan and Carl Jung. A close examination of auteur theory, the unique voice Burton has established through his iconic cinematic techniques, now coined ‘the Burtonesque’, will also be applied to provide a fuller and rounder interrogation. The focus of this project is to investigate thempsychoanalytical elements found in the texts and films, in order to clearly illustrate how Tim Burton’s cinematic approach serves to highlight a psychoanalytic interpretation.
- Full Text:
- Date Issued: 2015
Polyurethane composite adsorbent using solid phase extraction method for preconcentration of metal ion from aqueous solution
- Olorundare, O F, Msagati, T A M, Okonkwo, J O, Krause, Rui W M, Mamba, Bhekie B
- Authors: Olorundare, O F , Msagati, T A M , Okonkwo, J O , Krause, Rui W M , Mamba, Bhekie B
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125386 , vital:35778 , https://doi.org/10.1007/s13762-014-0645-5
- Description: Polyurethane composite adsorbent polymeric material was prepared and investigated for selected solid-phase extraction for metal ions, prior to its determination by inductively coupled plasma optical emission spectrometry. The surface characterisation was done using Fourier transform infrared spectroscopy. The separation and preconcentration conditions of the analytes investigated includes influence of pH, sample loading flow rate, elution flow rate, type and concentration of eluents. The optimum pH for the highest efficient recoveries for all metal ions, which ranged from 70 to 85 %, is pH 7. The metal ions were quantitatively eluted with 5 mL of 2 mol/L HNO3. Common coexisting ions did not interfere with the separation. The percentage recovery of the metal ions ranged between 70 and 89 %, while the results for the limit of detection and limit of quantification ranged from 0.249 to 0.256 and 0.831 to 0.855, respectively. The experimental tests showed good preconcentration results of trace levels of metal ions using synthesised polyurethane polymer adsorbent composite.
- Full Text:
- Date Issued: 2015
- Authors: Olorundare, O F , Msagati, T A M , Okonkwo, J O , Krause, Rui W M , Mamba, Bhekie B
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125386 , vital:35778 , https://doi.org/10.1007/s13762-014-0645-5
- Description: Polyurethane composite adsorbent polymeric material was prepared and investigated for selected solid-phase extraction for metal ions, prior to its determination by inductively coupled plasma optical emission spectrometry. The surface characterisation was done using Fourier transform infrared spectroscopy. The separation and preconcentration conditions of the analytes investigated includes influence of pH, sample loading flow rate, elution flow rate, type and concentration of eluents. The optimum pH for the highest efficient recoveries for all metal ions, which ranged from 70 to 85 %, is pH 7. The metal ions were quantitatively eluted with 5 mL of 2 mol/L HNO3. Common coexisting ions did not interfere with the separation. The percentage recovery of the metal ions ranged between 70 and 89 %, while the results for the limit of detection and limit of quantification ranged from 0.249 to 0.256 and 0.831 to 0.855, respectively. The experimental tests showed good preconcentration results of trace levels of metal ions using synthesised polyurethane polymer adsorbent composite.
- Full Text:
- Date Issued: 2015
The impact of decentralisation on participatory development in the Nsanje district of Malawi
- Simwaka, Rodin Rams Kapelele Atughanire
- Authors: Simwaka, Rodin Rams Kapelele Atughanire
- Date: 2015
- Subjects: Community development -- Malawi , Decentralization in government -- Malawi
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9255 , http://hdl.handle.net/10948/d1021206
- Description: This research investigated the impact of decentralisation on participatory development in the Nsanje District of Malawi from 2009 to 2014. Existing challenges in realising effective participation were identified by acquiring information from documents at three spheres of government, namely local, district and national. The literature explains decentralisation and local government; the theories of state-local relations; the nature, types and determinants of participation; the legislative framework of local government; and decentralisation reforms being implemented in Malawi. A descriptive approach was used in the study, with the emphasis on collecting data from primary sources such as minutes, reports, newspapers, and secondary sources such as the District Council and local government department records, books, academic journals, completed and unpublished post-graduate research theses, and legislation. From the acquired information, a number of recommendations are made to deal with various challenges faced to achieve effective participatory development in the District.
- Full Text:
- Date Issued: 2015
- Authors: Simwaka, Rodin Rams Kapelele Atughanire
- Date: 2015
- Subjects: Community development -- Malawi , Decentralization in government -- Malawi
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9255 , http://hdl.handle.net/10948/d1021206
- Description: This research investigated the impact of decentralisation on participatory development in the Nsanje District of Malawi from 2009 to 2014. Existing challenges in realising effective participation were identified by acquiring information from documents at three spheres of government, namely local, district and national. The literature explains decentralisation and local government; the theories of state-local relations; the nature, types and determinants of participation; the legislative framework of local government; and decentralisation reforms being implemented in Malawi. A descriptive approach was used in the study, with the emphasis on collecting data from primary sources such as minutes, reports, newspapers, and secondary sources such as the District Council and local government department records, books, academic journals, completed and unpublished post-graduate research theses, and legislation. From the acquired information, a number of recommendations are made to deal with various challenges faced to achieve effective participatory development in the District.
- Full Text:
- Date Issued: 2015
The relative contribution of non-timber forest products, agriculture and off-farm sources of income to rural households in Koloni and Guquka, Eastern Cape
- Authors: Mtati, Nosiseko
- Date: 2015
- Subjects: Informal sector (Economics) -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Forest products -- South Africa -- Eastern Cape , Non-timber forest products -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Natural resources -- South Africa -- Eastern Cape , Income -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4785 , http://hdl.handle.net/10962/d1018193
- Description: [Partial abstract]: This study was carried out to determine the contribution of non-timber forest products (NTFPs) to household total income, other livelihood sectors were also examined simultaneously. The contribution of agriculture involved livestock and crop production. Wages and government grants were other livelihood sectors that were looked into. This study was important in determining the change in livelihood strategies in the last decade and to quantify the NTFPs used at the two sites. It was carried out in Guquka and Koloni, both part of the central Eastern Cape. Information on direct use value of the NTFPs used, the quantities and local price; crop production outputs and inputs and the costs. Data were collected via a questionnaire.
- Full Text:
- Date Issued: 2015
- Authors: Mtati, Nosiseko
- Date: 2015
- Subjects: Informal sector (Economics) -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Forest products -- South Africa -- Eastern Cape , Non-timber forest products -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Natural resources -- South Africa -- Eastern Cape , Income -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4785 , http://hdl.handle.net/10962/d1018193
- Description: [Partial abstract]: This study was carried out to determine the contribution of non-timber forest products (NTFPs) to household total income, other livelihood sectors were also examined simultaneously. The contribution of agriculture involved livestock and crop production. Wages and government grants were other livelihood sectors that were looked into. This study was important in determining the change in livelihood strategies in the last decade and to quantify the NTFPs used at the two sites. It was carried out in Guquka and Koloni, both part of the central Eastern Cape. Information on direct use value of the NTFPs used, the quantities and local price; crop production outputs and inputs and the costs. Data were collected via a questionnaire.
- Full Text:
- Date Issued: 2015
The gentle pressure of the sky
- Authors: Watermeyer, Laura
- Date: 2015
- Subjects: South African fiction (English) -- 21st century , South African fiction (English) -- Study and teaching (Higher) , South African poetry (English) -- Study and teaching (Higher) , Creative writing (Higher education) -- South Africa , Short stories, South African -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5996 , http://hdl.handle.net/10962/d1017780
- Description: A collection of lyrical, imaginative prose, ranging from prose poems to more formal short stories to flash fiction. I challenge the ordinary or commonplace by exploring the realms between fiction and poetry, realism and fantasy, reality and illusion. I would like reading the collection to be a sensory experience, one that draws the reader deeper into the imaginary. Stylistically, I work elements of poetic language into the narrative in order to express the mystery and remoteness that the stories require.
- Full Text:
- Date Issued: 2015
- Authors: Watermeyer, Laura
- Date: 2015
- Subjects: South African fiction (English) -- 21st century , South African fiction (English) -- Study and teaching (Higher) , South African poetry (English) -- Study and teaching (Higher) , Creative writing (Higher education) -- South Africa , Short stories, South African -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5996 , http://hdl.handle.net/10962/d1017780
- Description: A collection of lyrical, imaginative prose, ranging from prose poems to more formal short stories to flash fiction. I challenge the ordinary or commonplace by exploring the realms between fiction and poetry, realism and fantasy, reality and illusion. I would like reading the collection to be a sensory experience, one that draws the reader deeper into the imaginary. Stylistically, I work elements of poetic language into the narrative in order to express the mystery and remoteness that the stories require.
- Full Text:
- Date Issued: 2015
An investigation into the role played by perceived security concerns in the adoption of mobile money services : a Zimbabwean case study
- Authors: Madebwe, Charles
- Date: 2015
- Subjects: Banks and banking, Mobile -- Zimbabwe , Global system for mobile communications , Cell phones -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4711 , http://hdl.handle.net/10962/d1017933
- Description: The ubiquitous nature of mobile phones and their popularity has led to opportunistic value added services (VAS), such as mobile money, riding on this phenomenon to be implemented. Several studies have been done to find factors that influence the adoption of mobile money and other information systems. The thesis looks at factors determining the uptake of mobile money over cellular networks with a special emphasis on aspects relating to perceived security even though other factors namely perceived usefulness, perceived ease of use, perceived trust and perceived cost were also looked at. The research further looks at the security threats introduced to mobile money by virtue of the nature, architecture, standards and protocols of Global System for Mobile Communications (GSM). The model employed for this research was the Technology Acceptance Model (TAM). Literature review was done on the security of GSM. Data was collected from a sample population around Harare, Zimbabwe using physical questionnaires. Statistical tests were performed on the collected data to find the significance of each construct to mobile money adoption. The research has found positive correlation between perceived security concerns and the adoption of money mobile money services over cellular networks. Perceived usefulness was found to be the most important factor in the adoption of mobile money. The research also found that customers need to trust the network service provider and the systems in use for them to adopt mobile money. Other factors driving consumer adoption were found to be perceived ease of use and perceived cost. The findings show that players who intend to introduce mobile money should strive to offer secure and useful systems that are trustworthy without making the service expensive or difficult to use. Literature review done showed that there is a possibility of compromising mobile money transactions done over GSM
- Full Text:
- Date Issued: 2015
- Authors: Madebwe, Charles
- Date: 2015
- Subjects: Banks and banking, Mobile -- Zimbabwe , Global system for mobile communications , Cell phones -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4711 , http://hdl.handle.net/10962/d1017933
- Description: The ubiquitous nature of mobile phones and their popularity has led to opportunistic value added services (VAS), such as mobile money, riding on this phenomenon to be implemented. Several studies have been done to find factors that influence the adoption of mobile money and other information systems. The thesis looks at factors determining the uptake of mobile money over cellular networks with a special emphasis on aspects relating to perceived security even though other factors namely perceived usefulness, perceived ease of use, perceived trust and perceived cost were also looked at. The research further looks at the security threats introduced to mobile money by virtue of the nature, architecture, standards and protocols of Global System for Mobile Communications (GSM). The model employed for this research was the Technology Acceptance Model (TAM). Literature review was done on the security of GSM. Data was collected from a sample population around Harare, Zimbabwe using physical questionnaires. Statistical tests were performed on the collected data to find the significance of each construct to mobile money adoption. The research has found positive correlation between perceived security concerns and the adoption of money mobile money services over cellular networks. Perceived usefulness was found to be the most important factor in the adoption of mobile money. The research also found that customers need to trust the network service provider and the systems in use for them to adopt mobile money. Other factors driving consumer adoption were found to be perceived ease of use and perceived cost. The findings show that players who intend to introduce mobile money should strive to offer secure and useful systems that are trustworthy without making the service expensive or difficult to use. Literature review done showed that there is a possibility of compromising mobile money transactions done over GSM
- Full Text:
- Date Issued: 2015
Production of Cydia pomonella granulovirus (CpGV) in a heteralogous host, Thaumatotibia Leucotreta (Meyrick) (False codling moth)
- Authors: Chambers, Craig Brian
- Date: 2015
- Subjects: Cryptophlebia leucotreta -- South Africa , Codling moth -- South Africa , Apples -- Diseases and pests -- South Africa , Codling moth -- Biological control -- South Africa , Insect pests -- Biological control -- South Africa , Biological pest control agents -- South Africa , Baculoviruses -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5935 , http://hdl.handle.net/10962/d1017906
- Description: Cydia pomonella (Linnaeus) (Family: Tortricidae), the codling moth, is considered one of the most significant pests of apples and pears worldwide, causing up to 80% crop loss in orchards if no control measures are applied. Cydia pomonella is oligophagous feeding on a number of alternate hosts including quince, walnuts, apricots, peaches, plums and nectarines. Historically the control of this pest has been achieved with the use of various chemical control strategies which have maintained pest levels below the economic threshold at a relatively low cost to the grower. However, there are serious concerns surrounding the use of chemical insecticides including the development of resistance in insect populations, the banning of various insecticides, regulations for lowering of the maximum residue level and employee and consumer safety. For this reason, alternate measures of control are slowly being adopted by growers such as mating disruption, cultural methods and the use of baculovirus biopesticides as part of integrated pest management programmes. The reluctance of growers to accept baculovirus or other biological control products in the past has been due to questionable product quality and inconsistencies in their field performance. Moreover, the development and application of biological control products is more costly than the use of chemical alternatives. Baculoviruses are arthropod specific viruses that are highly virulent to a number of lepidopteran species. Due to the virulence and host specificity of baculoviruses, Cydia pomonella granulovirus has been extensively and successfully used as part of integrated pest management systems for the control of C. pomonella in Europe and around the world, including South Africa. Commercial formulations have been typically based on the Mexican strain of CpGV. However due to long-term multiple applications of CpGV and the reliance on CpGV in organic farming practices in Europe, resistance to the CpGV-M strain has developed in a number of field populations of C. pomonella. This study aimed to identify and characterize novel isolates of CpGV in South Africa and compare their virulence with the commercial standard CpGV-M. Secondly, since C. pomonella is difficult to culture on a large scale, an alternate method of CpGV production was investigated in order to determine if CpGV could be produced more efficiently and at a reduced cost without negatively impacting the quality of the product. Several isolates of CpGV were recovered either from field collected larvae or from a laboratory-reared C. pomonella colony. Characterisation of DNA profiles using a variety of restriction enzymes revealed that only a single isolate, CpGV-SA, was genetically different from the Mexican strain of the virus used in the commercially available CpGV based products in South Africa. In dose-response bioassays using CpGV-SA, LC₅₀ and LC₉₀ values for neonate C. pomonella larvae were 3.18 x 10³ OBs/ml and 7.33 x 10⁴ respectively. A comparison of these values with those of CpGV-M indicated no significant difference in the virulence of the two isolates under laboratory conditions. This is a first report of a genetically distinct CpGV isolate in South Africa. The biological activity and novelty of CpGV-SA makes this isolate a potentially important tool for CpGV resistance management in South Africa. In order to justify production of CpGV in an alternative host, studies on the comparative biological performance of C. pomonella and T. leucotreta based on oviposition, time to hatch, larval developmental times and rearing efficiency as well as production costs were performed. Thaumatotibia leucotreta was found to be more fecund and to have significantly shorter egg and larval developmental times. In addition, larval production per unit of artificial diet was significantly higher than for C. pomonella. This resulted in T. leucotreta being more cost effective to produce with implications for reduced insectary space, sanitation practices as well as the labour component of production. Virus yield data generated by inoculation both C. pomonella and T. leucotreta with nine concentrations of CpGV resulted in comparable virus yields, justifying the continuation of the research into production of CpGV in T. leucotreta. It was important to determine the LC and LT values required for mass production of CpGV in late instar T. leucotreta larvae. Dose- and time-response bioassays with CpGV-M were conducted on artificial diet to determine these values. Fourth instar LC₅₀ and LC₉₀ values were 5.96 x 10³ OBs/ml and 1.64 x 10⁵ OBs/ml respectively. LT50 and LT90 values were 81.10 hours and 88.58 hours respectively. Fifth instar LC₅₀ and LC₉₀ values were 6.88 x 10⁴ OBs/ml and 9.78 x 10⁶ OBs/ml respectively. LT₅₀ and LT₉₀ values were 111.56 hours and 137.57 hours respectively. Virus produced in fourth instar T. leucotreta larvae was bioassayed against C. pomonella neonate larvae and compared to CpGV-M to establish if production in the heterologous host negatively affected the virulence of the isolate. No significant difference in virulence was observed between virus produced in T. leucotreta and that produced in C. pomonella. The data generated in the bioassays was used in CpGV mass production trials to evaluate production. All production methods tested produced acceptable virus yields. To examine the quality of the virus product, genomic DNA was extracted from larval cadavers and subjected to REN analysis with HindIII. The resulting DNA profiles indicated that the virus product was contaminated with the homologous virus, CrleGV. Based on the above results, the use of T. leucotreta as an alternate host for the in vivo production of CpGV on a commercial basis is not at this stage viable and requires further investigation before this production methodology can be reliable used to produce CpGV. However, this study has shown that CpGV can be produced in a homologous host, T. leucotreta and significant strides have been made towards developing a set of quality control standards that are essential for further development of successful production methodology. Finally a novel isolate of CpGV has been identified with comparable virulence to the CpGV-M. This is an important finding as it has broad reaching implications for resistance management of CpGV products in South Africa.
- Full Text:
- Date Issued: 2015
- Authors: Chambers, Craig Brian
- Date: 2015
- Subjects: Cryptophlebia leucotreta -- South Africa , Codling moth -- South Africa , Apples -- Diseases and pests -- South Africa , Codling moth -- Biological control -- South Africa , Insect pests -- Biological control -- South Africa , Biological pest control agents -- South Africa , Baculoviruses -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5935 , http://hdl.handle.net/10962/d1017906
- Description: Cydia pomonella (Linnaeus) (Family: Tortricidae), the codling moth, is considered one of the most significant pests of apples and pears worldwide, causing up to 80% crop loss in orchards if no control measures are applied. Cydia pomonella is oligophagous feeding on a number of alternate hosts including quince, walnuts, apricots, peaches, plums and nectarines. Historically the control of this pest has been achieved with the use of various chemical control strategies which have maintained pest levels below the economic threshold at a relatively low cost to the grower. However, there are serious concerns surrounding the use of chemical insecticides including the development of resistance in insect populations, the banning of various insecticides, regulations for lowering of the maximum residue level and employee and consumer safety. For this reason, alternate measures of control are slowly being adopted by growers such as mating disruption, cultural methods and the use of baculovirus biopesticides as part of integrated pest management programmes. The reluctance of growers to accept baculovirus or other biological control products in the past has been due to questionable product quality and inconsistencies in their field performance. Moreover, the development and application of biological control products is more costly than the use of chemical alternatives. Baculoviruses are arthropod specific viruses that are highly virulent to a number of lepidopteran species. Due to the virulence and host specificity of baculoviruses, Cydia pomonella granulovirus has been extensively and successfully used as part of integrated pest management systems for the control of C. pomonella in Europe and around the world, including South Africa. Commercial formulations have been typically based on the Mexican strain of CpGV. However due to long-term multiple applications of CpGV and the reliance on CpGV in organic farming practices in Europe, resistance to the CpGV-M strain has developed in a number of field populations of C. pomonella. This study aimed to identify and characterize novel isolates of CpGV in South Africa and compare their virulence with the commercial standard CpGV-M. Secondly, since C. pomonella is difficult to culture on a large scale, an alternate method of CpGV production was investigated in order to determine if CpGV could be produced more efficiently and at a reduced cost without negatively impacting the quality of the product. Several isolates of CpGV were recovered either from field collected larvae or from a laboratory-reared C. pomonella colony. Characterisation of DNA profiles using a variety of restriction enzymes revealed that only a single isolate, CpGV-SA, was genetically different from the Mexican strain of the virus used in the commercially available CpGV based products in South Africa. In dose-response bioassays using CpGV-SA, LC₅₀ and LC₉₀ values for neonate C. pomonella larvae were 3.18 x 10³ OBs/ml and 7.33 x 10⁴ respectively. A comparison of these values with those of CpGV-M indicated no significant difference in the virulence of the two isolates under laboratory conditions. This is a first report of a genetically distinct CpGV isolate in South Africa. The biological activity and novelty of CpGV-SA makes this isolate a potentially important tool for CpGV resistance management in South Africa. In order to justify production of CpGV in an alternative host, studies on the comparative biological performance of C. pomonella and T. leucotreta based on oviposition, time to hatch, larval developmental times and rearing efficiency as well as production costs were performed. Thaumatotibia leucotreta was found to be more fecund and to have significantly shorter egg and larval developmental times. In addition, larval production per unit of artificial diet was significantly higher than for C. pomonella. This resulted in T. leucotreta being more cost effective to produce with implications for reduced insectary space, sanitation practices as well as the labour component of production. Virus yield data generated by inoculation both C. pomonella and T. leucotreta with nine concentrations of CpGV resulted in comparable virus yields, justifying the continuation of the research into production of CpGV in T. leucotreta. It was important to determine the LC and LT values required for mass production of CpGV in late instar T. leucotreta larvae. Dose- and time-response bioassays with CpGV-M were conducted on artificial diet to determine these values. Fourth instar LC₅₀ and LC₉₀ values were 5.96 x 10³ OBs/ml and 1.64 x 10⁵ OBs/ml respectively. LT50 and LT90 values were 81.10 hours and 88.58 hours respectively. Fifth instar LC₅₀ and LC₉₀ values were 6.88 x 10⁴ OBs/ml and 9.78 x 10⁶ OBs/ml respectively. LT₅₀ and LT₉₀ values were 111.56 hours and 137.57 hours respectively. Virus produced in fourth instar T. leucotreta larvae was bioassayed against C. pomonella neonate larvae and compared to CpGV-M to establish if production in the heterologous host negatively affected the virulence of the isolate. No significant difference in virulence was observed between virus produced in T. leucotreta and that produced in C. pomonella. The data generated in the bioassays was used in CpGV mass production trials to evaluate production. All production methods tested produced acceptable virus yields. To examine the quality of the virus product, genomic DNA was extracted from larval cadavers and subjected to REN analysis with HindIII. The resulting DNA profiles indicated that the virus product was contaminated with the homologous virus, CrleGV. Based on the above results, the use of T. leucotreta as an alternate host for the in vivo production of CpGV on a commercial basis is not at this stage viable and requires further investigation before this production methodology can be reliable used to produce CpGV. However, this study has shown that CpGV can be produced in a homologous host, T. leucotreta and significant strides have been made towards developing a set of quality control standards that are essential for further development of successful production methodology. Finally a novel isolate of CpGV has been identified with comparable virulence to the CpGV-M. This is an important finding as it has broad reaching implications for resistance management of CpGV products in South Africa.
- Full Text:
- Date Issued: 2015
Post-treatment technologies for integrated algal pond systems
- Authors: Westensee, Dirk Karl
- Date: 2015
- Subjects: Sewage disposal plants -- South Africa -- Grahamstown , Water -- Purification -- Filtration , Water -- Purification -- Slow sand filtration , Sewage -- Purification -- Anaerobic treatment , Sewage -- Purification -- Biological treatment , Algae -- Biotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5958 , http://hdl.handle.net/10962/d1018180
- Description: Integrated Algae Pond Systems (IAPS) are a derivation of the Oswald designed Algal Integrated Wastewater Pond Systems (AIWPS®) and combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. IAPS technology was introduced to South Africa in 1996 and a pilot plant designed and commissioned at the Belmont Valley WWTW in Grahamstown. The system has been in continual use since implementation and affords a secondarily treated water for reclamation according to its design specifications which most closely resemble those of the AIWPS® Advanced Secondary Process developed by Oswald. As a consequence, and as might be expected, while the technology performed well and delivered a final effluent superior to most pond systems deployed in South Africa it was unable to meet The Department of Water Affairs General Standard for nutrient removal and effluent discharge. The work described in this thesis involved the design, construction, and evaluation of several tertiary treatment units (TTU') for incorporation into the IAPS process design. Included were; Maturation Ponds (MP), Slow Sand Filter (SSF) and Rock Filters (RF). Three MP's were constructed in series with a 12 day retention time and operated in parallel with a two-layered SSF and a three-stage RF. Water quality of the effluent emerging from each of these TTU's was monitored over a 10 month period. Significant decreases in the chemical oxygen demand (COD), ammonium-N, phosphate-P, nitrate-N, faecal coliforms (FC) and total coliforms (TC) were achieved by these TTU's. On average, throughout the testing period, water quality was within the statutory limit for discharge to a water course that is not a listed water course, with the exception of the total suspended solids (TSS). The RF was determined as the most suitable TTU for commercial use due to production of a better quality water, smaller footprint, lower construction costs and less maintenance required. From the results of this investigation it is concluded that commercial deployment of IAPS for the treatment of municipal sewage requires the inclusion of a suitable TTU. Furthermore, and based on the findings presented, RF appears most appropriate to ensure that quality of the final effluent meets the standard for discharge.
- Full Text:
- Date Issued: 2015
- Authors: Westensee, Dirk Karl
- Date: 2015
- Subjects: Sewage disposal plants -- South Africa -- Grahamstown , Water -- Purification -- Filtration , Water -- Purification -- Slow sand filtration , Sewage -- Purification -- Anaerobic treatment , Sewage -- Purification -- Biological treatment , Algae -- Biotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5958 , http://hdl.handle.net/10962/d1018180
- Description: Integrated Algae Pond Systems (IAPS) are a derivation of the Oswald designed Algal Integrated Wastewater Pond Systems (AIWPS®) and combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. IAPS technology was introduced to South Africa in 1996 and a pilot plant designed and commissioned at the Belmont Valley WWTW in Grahamstown. The system has been in continual use since implementation and affords a secondarily treated water for reclamation according to its design specifications which most closely resemble those of the AIWPS® Advanced Secondary Process developed by Oswald. As a consequence, and as might be expected, while the technology performed well and delivered a final effluent superior to most pond systems deployed in South Africa it was unable to meet The Department of Water Affairs General Standard for nutrient removal and effluent discharge. The work described in this thesis involved the design, construction, and evaluation of several tertiary treatment units (TTU') for incorporation into the IAPS process design. Included were; Maturation Ponds (MP), Slow Sand Filter (SSF) and Rock Filters (RF). Three MP's were constructed in series with a 12 day retention time and operated in parallel with a two-layered SSF and a three-stage RF. Water quality of the effluent emerging from each of these TTU's was monitored over a 10 month period. Significant decreases in the chemical oxygen demand (COD), ammonium-N, phosphate-P, nitrate-N, faecal coliforms (FC) and total coliforms (TC) were achieved by these TTU's. On average, throughout the testing period, water quality was within the statutory limit for discharge to a water course that is not a listed water course, with the exception of the total suspended solids (TSS). The RF was determined as the most suitable TTU for commercial use due to production of a better quality water, smaller footprint, lower construction costs and less maintenance required. From the results of this investigation it is concluded that commercial deployment of IAPS for the treatment of municipal sewage requires the inclusion of a suitable TTU. Furthermore, and based on the findings presented, RF appears most appropriate to ensure that quality of the final effluent meets the standard for discharge.
- Full Text:
- Date Issued: 2015