Incidence of porcine circovirus type 2 and porcine parvoviruses in swine herds of some communities in Eastern Cape, South Africa
- Authors: Afolabi, Kayode Olayinka
- Date: 2018
- Subjects: Swine -- Diseases Swine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9691 , vital:34820
- Description: Porcine circovirus type 2 (PCV2) is one of the swine pathogens of global economic importance. Since its first detection in early 1990s as the main etiologic agent of porcine multisystemic wasting syndrome (PMWS) and many other porcine circovirus-associated diseases (PCVAD), the virus has been extensively studied and has been found to be present in virtually all the pig producing countries of the world. As a viral pathogen that brings about clinical diseases aided by co-infecting pathogens, the involvement of many other viral agents including porcine parvoviruses (PPVs) have caught the attention of stakeholders worldwide. However, no surveillance study of the viral pathogens has been carried out in South Africa as there are little or no information on their prevalence in the swine herds of the country. This present study therefore aimed at detection and molecular characterization of PCV2 and PPVs in swine herds of some selected communities in Eastern Cape Province, South Africa. A total of 375 field samples were collected from seven commercial and communal farms from three District Municipalities of Eastern Cape, South Africa between 2015 and 2016. Structured questionnaires were also administered to each farm at the time of sample collection to obtain some important information relating to health status and farm management practices in the sampled farms. With the aid of conventional PCR method, 339 samples were initially screened for the presence of PCV2; positive amplicons were sequenced and obtained partial genomes of the virus were preliminarily analyzed. In order to obtain the complete genomes of the virus, four overlapping primer pairs were used to amplify the full-genome of PCV2 from the initial positive samples; amplified genomes were sequenced using the Sanger methods, sequenced PCV2 genomes were assembled and characterized. Furthermore, the prevalences of some designated PPVs in the sampled farms were obtained using 110 samples randomly selected from the previously archived samples and screened with 6 different primer pairs specific for the detection of 7 PPVs. All the amplified parvoviruses’ genomes were sequenced; their sequenced partial genomes were subsequently base-culled and analysed. The data obtained revealed that 54/339 (15.93 percent) samples from the swine herds were positive for PCV2; whereas the degree of occurrence of the viral pathogen as observed at farm level ranges from approximately 5.6 to 60 percent. The majority 15/17 (88 percent) of the analyzed partial sequences were found clustering with other PCV2b strains in the phylogenetic analysis. More interestingly, two other sequences obtained were also found clustering within PCV2d genotype in the initial screening and analysis. Furthermore, 15 complete PCV2 genomes were successfully amplified, sequenced and assembled. NJ and ML phylogenetic analysis of the complete ORF2 gene and full genomes unanimously showed 11 of the assembled genomes belonging to genotype PCV2b. Another 3 of the characterized sequences formed clade with other reference mutant PCV2b and PCV2b subtype 1C (PCV2d) strains from different parts of the world. The last sequence however, clustered with other reference strains belonging to PCV2 intermediate clade 2 (PCV2-IM2) recently identified in a global PCV2 strains phylogenetic analysis. Other genetic analyses including multiple sequence alignment and p-distance analysis also confirmed the outcomes of the phylogenetic analyses of the complete capsid gene and fullgenomes of the virus. On the other hand, the findings of the molecular profiling for PPVs showed that all the screened parvoviruses were present in the study area, having prevalence of 29.1 percent (PPV1), 21.8 percent (PPV2), 5.5 percent (PPV3), 43.6 percent (PPV4), 21.8 percent (PBo-likeV) and 44.6 percent for PBoV1 and PBoV2. Double infection of the screened PPVs was observed to be very rampant among the pigs as high as 20/110 (18.2 percent) for PPV2/PPV4 and PPV4/PBoV; followed by 19/110 (17.3 percent) of the samples for PPV1/PPV4 and PPV1/PBoV. Three of the viruses were found simultaneously in 19 of the screened samples representing 17.3 percent, whereas 8 (7.3 percent) samples were positive for four of the viruses. Phylogenetic analyses of PPV1, PPV2 and PBoVs 1 and 2 were conducted with two major clades homologous for each of them. This is the first report of PCV2 in swine herds of the Province and the first detection of PCV2b, PCV2d and PCV2-IM2 strains in South African swine herds. It follows the first reported case of PCV2a in an outbreak of porcine multisystemic wasting syndrome (PMWS) in Gauteng Province, South Africa over two decades ago. Also, this is the first major epidemiologic study on PPVs in the country following the initial case study of 1975. These findings confirmed the presence of the allimportant viral pathogens among pigs and also give preliminary insights into the possibility of co-infections of the pathogens in the studied area. This could however result in a serious large scale outbreak of devastating disease(s) associated with the viral pathogens, thereby ultimately resulting in huge economic losses if no appropriate measures are taken to effectively curb their spread across the country.
- Full Text:
- Date Issued: 2018
- Authors: Afolabi, Kayode Olayinka
- Date: 2018
- Subjects: Swine -- Diseases Swine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9691 , vital:34820
- Description: Porcine circovirus type 2 (PCV2) is one of the swine pathogens of global economic importance. Since its first detection in early 1990s as the main etiologic agent of porcine multisystemic wasting syndrome (PMWS) and many other porcine circovirus-associated diseases (PCVAD), the virus has been extensively studied and has been found to be present in virtually all the pig producing countries of the world. As a viral pathogen that brings about clinical diseases aided by co-infecting pathogens, the involvement of many other viral agents including porcine parvoviruses (PPVs) have caught the attention of stakeholders worldwide. However, no surveillance study of the viral pathogens has been carried out in South Africa as there are little or no information on their prevalence in the swine herds of the country. This present study therefore aimed at detection and molecular characterization of PCV2 and PPVs in swine herds of some selected communities in Eastern Cape Province, South Africa. A total of 375 field samples were collected from seven commercial and communal farms from three District Municipalities of Eastern Cape, South Africa between 2015 and 2016. Structured questionnaires were also administered to each farm at the time of sample collection to obtain some important information relating to health status and farm management practices in the sampled farms. With the aid of conventional PCR method, 339 samples were initially screened for the presence of PCV2; positive amplicons were sequenced and obtained partial genomes of the virus were preliminarily analyzed. In order to obtain the complete genomes of the virus, four overlapping primer pairs were used to amplify the full-genome of PCV2 from the initial positive samples; amplified genomes were sequenced using the Sanger methods, sequenced PCV2 genomes were assembled and characterized. Furthermore, the prevalences of some designated PPVs in the sampled farms were obtained using 110 samples randomly selected from the previously archived samples and screened with 6 different primer pairs specific for the detection of 7 PPVs. All the amplified parvoviruses’ genomes were sequenced; their sequenced partial genomes were subsequently base-culled and analysed. The data obtained revealed that 54/339 (15.93 percent) samples from the swine herds were positive for PCV2; whereas the degree of occurrence of the viral pathogen as observed at farm level ranges from approximately 5.6 to 60 percent. The majority 15/17 (88 percent) of the analyzed partial sequences were found clustering with other PCV2b strains in the phylogenetic analysis. More interestingly, two other sequences obtained were also found clustering within PCV2d genotype in the initial screening and analysis. Furthermore, 15 complete PCV2 genomes were successfully amplified, sequenced and assembled. NJ and ML phylogenetic analysis of the complete ORF2 gene and full genomes unanimously showed 11 of the assembled genomes belonging to genotype PCV2b. Another 3 of the characterized sequences formed clade with other reference mutant PCV2b and PCV2b subtype 1C (PCV2d) strains from different parts of the world. The last sequence however, clustered with other reference strains belonging to PCV2 intermediate clade 2 (PCV2-IM2) recently identified in a global PCV2 strains phylogenetic analysis. Other genetic analyses including multiple sequence alignment and p-distance analysis also confirmed the outcomes of the phylogenetic analyses of the complete capsid gene and fullgenomes of the virus. On the other hand, the findings of the molecular profiling for PPVs showed that all the screened parvoviruses were present in the study area, having prevalence of 29.1 percent (PPV1), 21.8 percent (PPV2), 5.5 percent (PPV3), 43.6 percent (PPV4), 21.8 percent (PBo-likeV) and 44.6 percent for PBoV1 and PBoV2. Double infection of the screened PPVs was observed to be very rampant among the pigs as high as 20/110 (18.2 percent) for PPV2/PPV4 and PPV4/PBoV; followed by 19/110 (17.3 percent) of the samples for PPV1/PPV4 and PPV1/PBoV. Three of the viruses were found simultaneously in 19 of the screened samples representing 17.3 percent, whereas 8 (7.3 percent) samples were positive for four of the viruses. Phylogenetic analyses of PPV1, PPV2 and PBoVs 1 and 2 were conducted with two major clades homologous for each of them. This is the first report of PCV2 in swine herds of the Province and the first detection of PCV2b, PCV2d and PCV2-IM2 strains in South African swine herds. It follows the first reported case of PCV2a in an outbreak of porcine multisystemic wasting syndrome (PMWS) in Gauteng Province, South Africa over two decades ago. Also, this is the first major epidemiologic study on PPVs in the country following the initial case study of 1975. These findings confirmed the presence of the allimportant viral pathogens among pigs and also give preliminary insights into the possibility of co-infections of the pathogens in the studied area. This could however result in a serious large scale outbreak of devastating disease(s) associated with the viral pathogens, thereby ultimately resulting in huge economic losses if no appropriate measures are taken to effectively curb their spread across the country.
- Full Text:
- Date Issued: 2018
Community policing and partnership policing : a case study of shared responsibilities between the police and Alice community
- Authors: Manganyi, Foster Mzamani
- Date: 2017
- Subjects: Police-community relations -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , DPhil
- Identifier: http://hdl.handle.net/10353/8386 , vital:32558
- Description: The purpose of this study was to explore the shared responsibilities between the police and the community on crime prevention. Various authorities such as Sir Robert Peel (1829), Sower (1957), William and Kelling (1982), Roelofse (2007), to mention a few, had been advocating community policing as an essential component of democratic policing. In an attempt to understand the shared responsibilities between the police and the community, a thorough literature review had been presented in chapter two. Through the intertwined approach of secondary data, explorations had been noted on the shared responsibility between the police and the community. Literature and theoretical review had been presented in the thesis to clarify critical aspects of the topic. Triangulation approach was adopted for the purpose of this study. The researcher triangulated, methodologies, sampling methods, data collection methods as well as data analysis methods. Using qualitative approach in Phase A, data was collected through structured interview, observation and content analysis which was thematically presented. The quantitative data (Phase B) was collected through structured questionnaire. In case of codding and analysis SPSS was utilised. The findings of the study in chapter six shows the shared responsibilities between the police and the community exist within Alice. Moreover, the findings shows that there is a need for community empowerment on human rights and its applicability.
- Full Text:
- Date Issued: 2017
- Authors: Manganyi, Foster Mzamani
- Date: 2017
- Subjects: Police-community relations -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , DPhil
- Identifier: http://hdl.handle.net/10353/8386 , vital:32558
- Description: The purpose of this study was to explore the shared responsibilities between the police and the community on crime prevention. Various authorities such as Sir Robert Peel (1829), Sower (1957), William and Kelling (1982), Roelofse (2007), to mention a few, had been advocating community policing as an essential component of democratic policing. In an attempt to understand the shared responsibilities between the police and the community, a thorough literature review had been presented in chapter two. Through the intertwined approach of secondary data, explorations had been noted on the shared responsibility between the police and the community. Literature and theoretical review had been presented in the thesis to clarify critical aspects of the topic. Triangulation approach was adopted for the purpose of this study. The researcher triangulated, methodologies, sampling methods, data collection methods as well as data analysis methods. Using qualitative approach in Phase A, data was collected through structured interview, observation and content analysis which was thematically presented. The quantitative data (Phase B) was collected through structured questionnaire. In case of codding and analysis SPSS was utilised. The findings of the study in chapter six shows the shared responsibilities between the police and the community exist within Alice. Moreover, the findings shows that there is a need for community empowerment on human rights and its applicability.
- Full Text:
- Date Issued: 2017
The effects of Real Exchange Rate (RER) on the export competitiveness of South African fruit industry
- Authors: Peter, Bathathu
- Date: 2017
- Subjects: Foreign exchange rates -- South Africa Free trade -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15732 , vital:40514
- Description: South Africa has diverse climatic conditions that allow it to grow and produce various fruit cultivars across the country. Limpopo, Western Cape, Mpumalanga, Eastern Cape, KwaZulu-Natal, and Northern Cape are South Africa’s main fruit production regions. In 2015, fruits ranked the 7th largest sector on exports and the largest in South Africa’s agricultural exports. South Africa’s major export partners for fruit in the same year were Netherlands, United Kingdom, Russian Federation, United Arab Emirate, and Hong Kong China. Correspondingly, exports to non-traditional markets such as India and China have increased rapidly. South Africa has prioritized exports as the engine for economic growth and job creation. The country has two major export destinations namely; the high income countries of Europe and North America, and the low-income markets of Africa, especially Southern African Customs Union (SADC) countries. South Africa’s Real Exchange Rates (RER) fluctuated widely since early 1970’s. This occurred after the collapse of the Bretton Woods system of fixed exchange rates in 1973. South Africa’s RER has been depreciating since then. Consequently, there has been a proliferation of debates on the relationship between the RER and exports performance. The most commonly held belief is that the RER depresses trade thereby increasing riskiness of trading activity. The South African fruit industry has been operating in the background of the depreciating RER. A high degree of RER volatility has posed a serious challenge to policy making environment because the magnitude of its impacts on trade flows is still unknown. The policy making environment becomes stagnant. Policy makers and researchers continue to examine the effects of RER on trade for an indefinite period. The South African fruit producers are unable to anticipate income earnings from trade due to increased risks associated with RER. South Africa’s agricultural sector encompasses the Historically Disadvantaged Individuals (HDI) which the country wants to prioritise and give them opportunities to participate in trade. The risks associated with the RER impair the development of the HDIs. The Thesis seeks to examine South Africa’s trade performance and the competitiveness of South African fruit industry as well as the effects of the RER. Specifically, the Thesis examines South Africa’s global fruit trade performance, explores the export competitiveness of South African fruit industry, and estimates the export demand equation for South African fruit exports to the world. The Thesis used the data obtained from the Department of Agriculture, Forestry and Fisheries (DAFF) for the period of 1080 to 2015 to estimate the export demand equation. The data from the International Trade Centre (ITC) for the period of 2001 to 2015 was used to examine South Africa’s global trade performance and competitiveness. The analytical framework followed incorporates the South Africa’s fruit Trade Performance Index (TPI) and the effects of RER on South African fruit industry. The TPI presents South Africa’s global fruit trade and its competitiveness using Trade Map, while the effects of RER are investigated on local fruit sales and on exports using the regression model. The Trade Map is the dominant trade analysis tool increasingly being used by the researchers and policy makers to make informed decisions on trade issues. The Thesis also made use of the Trade Map tools to examine South Africa’s global fruit trade performance and its competitiveness. The market analysis tools developed by the International Trade Centre (ITC) are: Trade Map, Market Access Map, Investment Map, Trade Competitiveness Map, Standard Map, and the Procurement Map. Trade Map, Trade Competitiveness Map, and the Market Access Map are used. Subsequently, the Thesis applied econometric techniques to examine the effects of RER on South Africa’s fruit exports and on fruit sales on local markets using the regression model. In this regard, the Thesis followed the export demand equation used by Todani and Munyama (2005). De Vita & Abbott (2004), and Tandra-Ragoobur & Emamdy (2011). Todani & Munyama (2005), to estimate the relationship between exchange rate volatility and South African export. Real exports and the exchange rate volatility were the main variables used in the model. The relative prices and the income of South Africa’s trading partner were also included in the model. The results show that South Africa was the 11th largest fruit exporter after Viet Nam and Spain in 2015. During the same year, the U.S. was the largest exporter of fruit with 14percent in the world, followed by Spain and Netherlands with 9percent and 6percent, respectively. The fruit industry ranked 8th largest exporter and the largest in agricultural sectors in 2015. Its exports totaled R 37 133 million in 2015, from R 30 566 million in 2014. South Africa’s total fruit exports accounted for a 33percent share on total agricultural exports and 4percent on South Africa’s total exports in 2015. The coefficients of the regression model were all statistically significant. Most importantly, an inverse relationship between the relative price and South Africa’s real fruit exports was established. Moreover, the RER had a significant negative effect on the South Africa’s fruit export competitiveness. This imposes more pain on the development of the HDIs in South Africa’s agricultural sector. South Africa has desire to move away from the export of raw materials and traditional export commodities and promote the export of value added products, including the agro processing products. Accordingly, this affects the entire value chain of the agricultural sector, since trade cannot be anticipated. On the basis of the regression results shown by the variables included in the model, the objectives of the study were accomplished. South Africa’s fruit exports are said to be more competitive to the European markets as a result of the weaker rand relative to other countries. The overview of South Africa’s fruit trade shows that South African fruit exports are more competitive across the globe. This is probably because the South Africa’s fruit exports for the top ten commodities are ranked almost the first five in the European markets and the first ten for the world. The results are supported by previous documented research, which emphasised that the weaker rand leads to more South African fruit produce being absorbed by the international markets. The evidence from the results shows that the RER stimulates the fruit export competitiveness.
- Full Text:
- Date Issued: 2017
- Authors: Peter, Bathathu
- Date: 2017
- Subjects: Foreign exchange rates -- South Africa Free trade -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15732 , vital:40514
- Description: South Africa has diverse climatic conditions that allow it to grow and produce various fruit cultivars across the country. Limpopo, Western Cape, Mpumalanga, Eastern Cape, KwaZulu-Natal, and Northern Cape are South Africa’s main fruit production regions. In 2015, fruits ranked the 7th largest sector on exports and the largest in South Africa’s agricultural exports. South Africa’s major export partners for fruit in the same year were Netherlands, United Kingdom, Russian Federation, United Arab Emirate, and Hong Kong China. Correspondingly, exports to non-traditional markets such as India and China have increased rapidly. South Africa has prioritized exports as the engine for economic growth and job creation. The country has two major export destinations namely; the high income countries of Europe and North America, and the low-income markets of Africa, especially Southern African Customs Union (SADC) countries. South Africa’s Real Exchange Rates (RER) fluctuated widely since early 1970’s. This occurred after the collapse of the Bretton Woods system of fixed exchange rates in 1973. South Africa’s RER has been depreciating since then. Consequently, there has been a proliferation of debates on the relationship between the RER and exports performance. The most commonly held belief is that the RER depresses trade thereby increasing riskiness of trading activity. The South African fruit industry has been operating in the background of the depreciating RER. A high degree of RER volatility has posed a serious challenge to policy making environment because the magnitude of its impacts on trade flows is still unknown. The policy making environment becomes stagnant. Policy makers and researchers continue to examine the effects of RER on trade for an indefinite period. The South African fruit producers are unable to anticipate income earnings from trade due to increased risks associated with RER. South Africa’s agricultural sector encompasses the Historically Disadvantaged Individuals (HDI) which the country wants to prioritise and give them opportunities to participate in trade. The risks associated with the RER impair the development of the HDIs. The Thesis seeks to examine South Africa’s trade performance and the competitiveness of South African fruit industry as well as the effects of the RER. Specifically, the Thesis examines South Africa’s global fruit trade performance, explores the export competitiveness of South African fruit industry, and estimates the export demand equation for South African fruit exports to the world. The Thesis used the data obtained from the Department of Agriculture, Forestry and Fisheries (DAFF) for the period of 1080 to 2015 to estimate the export demand equation. The data from the International Trade Centre (ITC) for the period of 2001 to 2015 was used to examine South Africa’s global trade performance and competitiveness. The analytical framework followed incorporates the South Africa’s fruit Trade Performance Index (TPI) and the effects of RER on South African fruit industry. The TPI presents South Africa’s global fruit trade and its competitiveness using Trade Map, while the effects of RER are investigated on local fruit sales and on exports using the regression model. The Trade Map is the dominant trade analysis tool increasingly being used by the researchers and policy makers to make informed decisions on trade issues. The Thesis also made use of the Trade Map tools to examine South Africa’s global fruit trade performance and its competitiveness. The market analysis tools developed by the International Trade Centre (ITC) are: Trade Map, Market Access Map, Investment Map, Trade Competitiveness Map, Standard Map, and the Procurement Map. Trade Map, Trade Competitiveness Map, and the Market Access Map are used. Subsequently, the Thesis applied econometric techniques to examine the effects of RER on South Africa’s fruit exports and on fruit sales on local markets using the regression model. In this regard, the Thesis followed the export demand equation used by Todani and Munyama (2005). De Vita & Abbott (2004), and Tandra-Ragoobur & Emamdy (2011). Todani & Munyama (2005), to estimate the relationship between exchange rate volatility and South African export. Real exports and the exchange rate volatility were the main variables used in the model. The relative prices and the income of South Africa’s trading partner were also included in the model. The results show that South Africa was the 11th largest fruit exporter after Viet Nam and Spain in 2015. During the same year, the U.S. was the largest exporter of fruit with 14percent in the world, followed by Spain and Netherlands with 9percent and 6percent, respectively. The fruit industry ranked 8th largest exporter and the largest in agricultural sectors in 2015. Its exports totaled R 37 133 million in 2015, from R 30 566 million in 2014. South Africa’s total fruit exports accounted for a 33percent share on total agricultural exports and 4percent on South Africa’s total exports in 2015. The coefficients of the regression model were all statistically significant. Most importantly, an inverse relationship between the relative price and South Africa’s real fruit exports was established. Moreover, the RER had a significant negative effect on the South Africa’s fruit export competitiveness. This imposes more pain on the development of the HDIs in South Africa’s agricultural sector. South Africa has desire to move away from the export of raw materials and traditional export commodities and promote the export of value added products, including the agro processing products. Accordingly, this affects the entire value chain of the agricultural sector, since trade cannot be anticipated. On the basis of the regression results shown by the variables included in the model, the objectives of the study were accomplished. South Africa’s fruit exports are said to be more competitive to the European markets as a result of the weaker rand relative to other countries. The overview of South Africa’s fruit trade shows that South African fruit exports are more competitive across the globe. This is probably because the South Africa’s fruit exports for the top ten commodities are ranked almost the first five in the European markets and the first ten for the world. The results are supported by previous documented research, which emphasised that the weaker rand leads to more South African fruit produce being absorbed by the international markets. The evidence from the results shows that the RER stimulates the fruit export competitiveness.
- Full Text:
- Date Issued: 2017
Towards the development of a mycoinsecticide to control white grubs (Coleoptera: Scarabaeidae) in South African sugarcane
- Authors: Goble, Tarryn Anne
- Date: 2013
- Subjects: Insecticides -- Environmental aspects Insecticides -- Toxicology Beetles -- South Africa -- KwaZulu-Natal Beetles -- Control -- South Africa -- KwaZulu-Natal Coleophoridae -- South Africa -- KwaZulu-Natal Scarabaeidae -- South Africa -- KwaZulu-Natal Sugarcane -- Diseases and pests -- South Africa -- KwaZulu-Natal Sugarcane -- Diseases and pests -- Control -- South Africa -- KwaZulu-Natal , Insecticides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5586 , http://hdl.handle.net/10962/d1001748
- Description: In the KwaZulu-Natal (KZN) Midlands North region of South Africa, the importance and increased prevalence of endemic scarabaeids, particularly Hypopholis sommeri Burmeister and Schizonycha affinis Boheman (Coleoptera: Melolonthinae), as soil pests of sugarcane, and a need for their control was established. The development of a mycoinsecticide offers an environmentally friendly alternative to chemical insecticides. The identification of a diversity of white grub species, in two Scarabaeidae subfamilies, representing seven genera were collected in sugarcane as a pest complex. Hypopholis sommeri and S. affinis were the most prevalent species. The increased seasonal abundances, diversity and highly aggregated nature of these scarabaeid species in summer months, suggested that targeting and control strategies for these pests should be considered in this season. Increased rainfall, relative humidity and soil temperatures were linked to the increased occurrence of scarab adults and neonate grubs. Beauveria brongniartii (Saccardo) Petch epizootics were recorded at two sites in the KZN Midlands North on H. sommeri. Seventeen different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria sp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the Beauveria bassiana senso stricto (Balsamo) Vuillemin and B. brongniartii species groups. These groupings were supported by two gene regions, the nuclear ribosomal Internal Transcribed Spacer (ITS) and the nuclear B locus (Bloc) gene of which 23 exemplar Beauveria isolates were represented and sequenced. When microsatellite data were analysed, 26 haplotypes among 58 isolates of B. brongniartii were distinguished. Relatively low levels of genetic diversity were detected in B. brongniartii and isolates were shown to be closely related. There was no genetic differentiation between the two sites, Harden Heights and Canema in the KZN Midlands North. High gene flow from swarming H. sommeri beetles is the proposed mechanism for this lack of genetic differentiation between populations. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from arboreal to subterranean habitats in the environment by H. sommeri beetles. This was the first record of this species of fungus causing epizootics on the larvae and adults of H. sommeri in South Africa. The virulence of 21 isolates of Beauveria brongniartii and two isolates of B. bassiana were evaluated against the adults and larvae of S. affinis and the adults of H. sommeri and Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae). Despite being closely-related, B. brongniartii isolates varied significantly in their virulence towards different hosts and highlighted the host specific nature of B. brongniartii towards S. affinis when compared to B. bassiana. Adults of S. affinis were significantly more susceptible to B. brongniartii isolates than the second (L2) or third instar (L3) grubs. The median lethal time (LT₅₀) of the most virulent B. brongniartii isolate (C13) against S. affinis adults was 7.8 days and probit analysis estimated a median lethal concentration (LC₅₀) of 4.4×10⁷ conidia/ml⁻¹. When L2 grubs were treated with a concentration of 1.0×10⁸ conidia/ml⁻¹, B. brongniartii isolates HHWG1, HHB39A and C17 caused mortality in L2 grubs within 18.4-19.8 days (LT₅₀). Beauveria brongniartii isolate HHWG1 was tested against the L3 grubs of S. affinis at four different concentrations. At the lowest concentration (1×10⁶ conidia/ml⁻¹), the LT₅₀ was 25.8 days, and at the highest concentration (1×10⁹ conidia/ml⁻¹) the LT₅₀ dropped to 15.1 days. The persistence of B. bassiana isolate 4222 formulated on rice and wheat bran and buried at eight field sites in the KZN Midlands North was evaluated by plating out a suspension of treated soil onto a selective medium. All eight field sites showed a significant decline in B. bassiana CFUs per gram of soil over time, with few conidia still present in the samples after a year. Greater declines in CFUs were observed at some sites but there were no significant differences observed in the persistence of conidia formulated on rice or wheat bran as carriers. Overall, poor persistence of B. bassiana isolate 4222 was attributed to suboptimum temperatures, rainfall, which rapidly degraded the nutritive carriers, attenuated fungal genotype and the action of antagonistic soil microbes. Growers’ perceptions of white grubs as pests and the feasibility of a mycoinsecticide market were evaluated by means of a semi-structured questionnaire. The study showed that the reduced feasibility of application, general lack of potential demand for a product, high cost factors and most importantly, the lack of pest perception, were factors which would negatively affect the adoption of a granular mycoinsecticide. Growers however exhibited a positive attitude towards mycoinsecticides, and showed all the relevant attributes for successful technology adoption. It is recommended that because B. brongniartii epizootics were recorded on target pests which indicated good host specificity, dispersal ability and persistence of the fungus in the intended environment of application; that a mycoinsecticide based on this fungal species be developed. What will likely increase adoption and success of a mycoinsecticide is collaboration between various industries partners to increases market potential in other crops such as Acacia mearnsii De Wild (Fabales: Fabaceae).
- Full Text:
- Date Issued: 2013
- Authors: Goble, Tarryn Anne
- Date: 2013
- Subjects: Insecticides -- Environmental aspects Insecticides -- Toxicology Beetles -- South Africa -- KwaZulu-Natal Beetles -- Control -- South Africa -- KwaZulu-Natal Coleophoridae -- South Africa -- KwaZulu-Natal Scarabaeidae -- South Africa -- KwaZulu-Natal Sugarcane -- Diseases and pests -- South Africa -- KwaZulu-Natal Sugarcane -- Diseases and pests -- Control -- South Africa -- KwaZulu-Natal , Insecticides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5586 , http://hdl.handle.net/10962/d1001748
- Description: In the KwaZulu-Natal (KZN) Midlands North region of South Africa, the importance and increased prevalence of endemic scarabaeids, particularly Hypopholis sommeri Burmeister and Schizonycha affinis Boheman (Coleoptera: Melolonthinae), as soil pests of sugarcane, and a need for their control was established. The development of a mycoinsecticide offers an environmentally friendly alternative to chemical insecticides. The identification of a diversity of white grub species, in two Scarabaeidae subfamilies, representing seven genera were collected in sugarcane as a pest complex. Hypopholis sommeri and S. affinis were the most prevalent species. The increased seasonal abundances, diversity and highly aggregated nature of these scarabaeid species in summer months, suggested that targeting and control strategies for these pests should be considered in this season. Increased rainfall, relative humidity and soil temperatures were linked to the increased occurrence of scarab adults and neonate grubs. Beauveria brongniartii (Saccardo) Petch epizootics were recorded at two sites in the KZN Midlands North on H. sommeri. Seventeen different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria sp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the Beauveria bassiana senso stricto (Balsamo) Vuillemin and B. brongniartii species groups. These groupings were supported by two gene regions, the nuclear ribosomal Internal Transcribed Spacer (ITS) and the nuclear B locus (Bloc) gene of which 23 exemplar Beauveria isolates were represented and sequenced. When microsatellite data were analysed, 26 haplotypes among 58 isolates of B. brongniartii were distinguished. Relatively low levels of genetic diversity were detected in B. brongniartii and isolates were shown to be closely related. There was no genetic differentiation between the two sites, Harden Heights and Canema in the KZN Midlands North. High gene flow from swarming H. sommeri beetles is the proposed mechanism for this lack of genetic differentiation between populations. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from arboreal to subterranean habitats in the environment by H. sommeri beetles. This was the first record of this species of fungus causing epizootics on the larvae and adults of H. sommeri in South Africa. The virulence of 21 isolates of Beauveria brongniartii and two isolates of B. bassiana were evaluated against the adults and larvae of S. affinis and the adults of H. sommeri and Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae). Despite being closely-related, B. brongniartii isolates varied significantly in their virulence towards different hosts and highlighted the host specific nature of B. brongniartii towards S. affinis when compared to B. bassiana. Adults of S. affinis were significantly more susceptible to B. brongniartii isolates than the second (L2) or third instar (L3) grubs. The median lethal time (LT₅₀) of the most virulent B. brongniartii isolate (C13) against S. affinis adults was 7.8 days and probit analysis estimated a median lethal concentration (LC₅₀) of 4.4×10⁷ conidia/ml⁻¹. When L2 grubs were treated with a concentration of 1.0×10⁸ conidia/ml⁻¹, B. brongniartii isolates HHWG1, HHB39A and C17 caused mortality in L2 grubs within 18.4-19.8 days (LT₅₀). Beauveria brongniartii isolate HHWG1 was tested against the L3 grubs of S. affinis at four different concentrations. At the lowest concentration (1×10⁶ conidia/ml⁻¹), the LT₅₀ was 25.8 days, and at the highest concentration (1×10⁹ conidia/ml⁻¹) the LT₅₀ dropped to 15.1 days. The persistence of B. bassiana isolate 4222 formulated on rice and wheat bran and buried at eight field sites in the KZN Midlands North was evaluated by plating out a suspension of treated soil onto a selective medium. All eight field sites showed a significant decline in B. bassiana CFUs per gram of soil over time, with few conidia still present in the samples after a year. Greater declines in CFUs were observed at some sites but there were no significant differences observed in the persistence of conidia formulated on rice or wheat bran as carriers. Overall, poor persistence of B. bassiana isolate 4222 was attributed to suboptimum temperatures, rainfall, which rapidly degraded the nutritive carriers, attenuated fungal genotype and the action of antagonistic soil microbes. Growers’ perceptions of white grubs as pests and the feasibility of a mycoinsecticide market were evaluated by means of a semi-structured questionnaire. The study showed that the reduced feasibility of application, general lack of potential demand for a product, high cost factors and most importantly, the lack of pest perception, were factors which would negatively affect the adoption of a granular mycoinsecticide. Growers however exhibited a positive attitude towards mycoinsecticides, and showed all the relevant attributes for successful technology adoption. It is recommended that because B. brongniartii epizootics were recorded on target pests which indicated good host specificity, dispersal ability and persistence of the fungus in the intended environment of application; that a mycoinsecticide based on this fungal species be developed. What will likely increase adoption and success of a mycoinsecticide is collaboration between various industries partners to increases market potential in other crops such as Acacia mearnsii De Wild (Fabales: Fabaceae).
- Full Text:
- Date Issued: 2013
Effect of cultivar on the quality of flax and hemp grown in South Africa
- Authors: Blouw, Langa Sunshine
- Date: 2012
- Subjects: Hemp -- South Africa , Flaxseed -- South Africa , Plant varieties , Textile industry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9387 , http://hdl.handle.net/10948/d1010997 , Hemp -- South Africa , Flaxseed -- South Africa , Plant varieties , Textile industry
- Description: Bast fibrous renewable materials, as commercial crops for the manufacture of textile based and other products, have been used for thousands of years to satisfy certain human needs, such as for shelter, clothing, source of energy and tools, and to sustain the livelihood of many communities in countries, such as in Asia, Europe and Africa. Concern for the environment has led to a number of global initiatives that favour the use of natural fibres. It is forecast that the global fibre demand by 2050 will be 130 million tonnes, which the cotton and synthetic fibre production will not be able to meet. Other than the environmental concerns, the renewed global interest in natural fibres, such as flax and hemp, forms part of a strategy to satisfy the fibre demand. South Africa, notwithstanding the fact that the flax and hemp industries have long been established for thousands of years in Europe, Asia and Egypt (Africa), has no history of the breeding, growing, processing and production of these cash crops. The renewed global interest in these crops has also stimulated interest from South Africa with respect to the development of a flax and hemp fibre industry so as to address some of the socio-economic challenges confronting the country today in its attempts to bring about real development in the rural areas through the cultivation and complete beneficiation of these fibre crops. In this regard, the relevant stakeholders, namely government, research councils, tertiary education institutions, farmers and communities worked together to investigate whether South Africa has the agronomic and climatic conditions, technical expertise as well as the necessary processing and production infrastructure to support the development of a local flax and hemp agro-industry. The purpose of this study was firstly to evaluate the performance of EU flax and hemp cultivars grown under different agronomic conditions in South Africa, and their effect on straw biomass yield, fibre yield and total fibre yield per hectare as well as associated fibre properties, and secondly to undertake mechanical fibre modification trials aimed at producing flax and hemp fibres with fibre diameters close to those of cotton. The minimum fibre diameter targeted being 20μm. In accordance with the project objectives and work plan, selected dew retted flax and hemp straw samples from the various planting sites selected by the Agriculture Research Council – Institute for Industrial Crops, representing all the agronomic conditions under investigation, were taken to the CSIR for fibre extraction and testing. A relatively inexpensive and easy to operate Russian designed and manufactured machine, the CMT-200M breaker-cum-scutcher, was used for fibre extraction and the resultant extracted fibre bundles were further refined, using a steel comb, to obtain optimal fibre separation before their physical and chemical properties were evaluated. Results obtained in this research study proved that the climatic and agronomic conditions in South Africa were suitable for the cultivation of flax and hemp, notwithstanding the fact that the fibre yields achieved for hemp were lower than the minimum criteria of 23 percent, and that for flax only just exceeded the 25 percent minimum. The lack of local technical expertise on the growing and retting of flax and hemp, contributed to the low fibre yields. The planting parameters which were found to produce good results for the cultivation of hemp were the October planting date, using a row spacing of between 12.5 to 25 cm, with a seeding density of between 80 – 100kg, and the application of 50 – 100kg nitrogen fertiliser. The use of extra artificial lighting and herbicide treatment did not appear to beneficially improve the hemp fibre yields. Similar considerations for flax cultivation in the Southern Cape region, particularly Oudtshoorn and Outeniqua, indicated that May to July planting dates, using inter-row spacing of 25cm and sowing density of 63kg seed.haˉ¹, produced a fibre yield and total fibre yield per hectare above the minimum values of 25 percent and 0,8 tonnes per hectare, respectively, quoted in the literature.
- Full Text:
- Date Issued: 2012
- Authors: Blouw, Langa Sunshine
- Date: 2012
- Subjects: Hemp -- South Africa , Flaxseed -- South Africa , Plant varieties , Textile industry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9387 , http://hdl.handle.net/10948/d1010997 , Hemp -- South Africa , Flaxseed -- South Africa , Plant varieties , Textile industry
- Description: Bast fibrous renewable materials, as commercial crops for the manufacture of textile based and other products, have been used for thousands of years to satisfy certain human needs, such as for shelter, clothing, source of energy and tools, and to sustain the livelihood of many communities in countries, such as in Asia, Europe and Africa. Concern for the environment has led to a number of global initiatives that favour the use of natural fibres. It is forecast that the global fibre demand by 2050 will be 130 million tonnes, which the cotton and synthetic fibre production will not be able to meet. Other than the environmental concerns, the renewed global interest in natural fibres, such as flax and hemp, forms part of a strategy to satisfy the fibre demand. South Africa, notwithstanding the fact that the flax and hemp industries have long been established for thousands of years in Europe, Asia and Egypt (Africa), has no history of the breeding, growing, processing and production of these cash crops. The renewed global interest in these crops has also stimulated interest from South Africa with respect to the development of a flax and hemp fibre industry so as to address some of the socio-economic challenges confronting the country today in its attempts to bring about real development in the rural areas through the cultivation and complete beneficiation of these fibre crops. In this regard, the relevant stakeholders, namely government, research councils, tertiary education institutions, farmers and communities worked together to investigate whether South Africa has the agronomic and climatic conditions, technical expertise as well as the necessary processing and production infrastructure to support the development of a local flax and hemp agro-industry. The purpose of this study was firstly to evaluate the performance of EU flax and hemp cultivars grown under different agronomic conditions in South Africa, and their effect on straw biomass yield, fibre yield and total fibre yield per hectare as well as associated fibre properties, and secondly to undertake mechanical fibre modification trials aimed at producing flax and hemp fibres with fibre diameters close to those of cotton. The minimum fibre diameter targeted being 20μm. In accordance with the project objectives and work plan, selected dew retted flax and hemp straw samples from the various planting sites selected by the Agriculture Research Council – Institute for Industrial Crops, representing all the agronomic conditions under investigation, were taken to the CSIR for fibre extraction and testing. A relatively inexpensive and easy to operate Russian designed and manufactured machine, the CMT-200M breaker-cum-scutcher, was used for fibre extraction and the resultant extracted fibre bundles were further refined, using a steel comb, to obtain optimal fibre separation before their physical and chemical properties were evaluated. Results obtained in this research study proved that the climatic and agronomic conditions in South Africa were suitable for the cultivation of flax and hemp, notwithstanding the fact that the fibre yields achieved for hemp were lower than the minimum criteria of 23 percent, and that for flax only just exceeded the 25 percent minimum. The lack of local technical expertise on the growing and retting of flax and hemp, contributed to the low fibre yields. The planting parameters which were found to produce good results for the cultivation of hemp were the October planting date, using a row spacing of between 12.5 to 25 cm, with a seeding density of between 80 – 100kg, and the application of 50 – 100kg nitrogen fertiliser. The use of extra artificial lighting and herbicide treatment did not appear to beneficially improve the hemp fibre yields. Similar considerations for flax cultivation in the Southern Cape region, particularly Oudtshoorn and Outeniqua, indicated that May to July planting dates, using inter-row spacing of 25cm and sowing density of 63kg seed.haˉ¹, produced a fibre yield and total fibre yield per hectare above the minimum values of 25 percent and 0,8 tonnes per hectare, respectively, quoted in the literature.
- Full Text:
- Date Issued: 2012
Evaluating the efficacy of training programmes for secondary school music teachers at higher education institutions in the province of the Eastern Cape
- Authors: Rademan, Carika
- Date: 2012
- Subjects: Music in universities and colleges -- South Africa , Music teachers -- Training of , School music -- Instruction and study , Teacher effectiveness
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:8522 , http://hdl.handle.net/10948/d1019925
- Description: Frequent changes in the school music curriculums in South Africa necessitated changes in teaching music in schools. Music teachers in secondary schools who are responsible for teaching music as a subject have been confronted with the challenges presented in such a changing educational climate and often found that their pre-service teacher training did not sufficiently prepare them for changing syllabi. The quality of teaching in schools is directly linked to the quality of teacher training at universities and when institutional policies prohibits pre-service teachers from qualifying themselves sufficiently for their in-service careers, frustration and disillusionment sets in. This study explores the perceptions of music teachers of the effectiveness of their pre-service training. It also explores the content of university music degree courses and whether it is in line with school music curricula. The study addressed the research questions through the use of questionnaires and interviews. The finding suggested that there is a need for teacher training courses to be adapted and contextualised so that there is continuum between university and school curriculums. This research also exposed the policies barring music graduates from fully qualifying themselves as teachers and raised important issues that music teacher educators need to address in order to ensure that music graduates are adequately prepared for classroom music teaching.
- Full Text:
- Date Issued: 2012
- Authors: Rademan, Carika
- Date: 2012
- Subjects: Music in universities and colleges -- South Africa , Music teachers -- Training of , School music -- Instruction and study , Teacher effectiveness
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:8522 , http://hdl.handle.net/10948/d1019925
- Description: Frequent changes in the school music curriculums in South Africa necessitated changes in teaching music in schools. Music teachers in secondary schools who are responsible for teaching music as a subject have been confronted with the challenges presented in such a changing educational climate and often found that their pre-service teacher training did not sufficiently prepare them for changing syllabi. The quality of teaching in schools is directly linked to the quality of teacher training at universities and when institutional policies prohibits pre-service teachers from qualifying themselves sufficiently for their in-service careers, frustration and disillusionment sets in. This study explores the perceptions of music teachers of the effectiveness of their pre-service training. It also explores the content of university music degree courses and whether it is in line with school music curricula. The study addressed the research questions through the use of questionnaires and interviews. The finding suggested that there is a need for teacher training courses to be adapted and contextualised so that there is continuum between university and school curriculums. This research also exposed the policies barring music graduates from fully qualifying themselves as teachers and raised important issues that music teacher educators need to address in order to ensure that music graduates are adequately prepared for classroom music teaching.
- Full Text:
- Date Issued: 2012
Application of macroinvertebrate based biomonitoring approaches to assess anthropogenic impacts in the Swartkops River, South Africa
- Authors: Odume, Oghenekaro Nelson
- Date: 2011
- Subjects: Water -- Pollution -- South Africa -- Swartkops River Water quality biological assessment -- South Africa -- Swartkops River Environmental monitoring -- South Africa -- Swartkops River Aquatic invertebrates -- Effect of water pollution on -- South Africa -- Swartkops River
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6040 , http://hdl.handle.net/10962/d1006199
- Description: A growing human population accompanied by urbanisation and industrialisation have led to over exploitation and pollution of freshwater resources and have consequently impacted on aquatic ecosystem health. The Swartkops River in the Eastern Cape of South Africa is no exception. It drains a heavily industrialised catchment which has led to deterioration of its water quality due to pollution. Integrated water resources management (IWRM) requires the concurrent sustainable use of water resources and the protection of aquatic ecosystem health. Macroinvertebrates are well known for their ability to reflect the health of the environment in which they live, thus they were used to assess anthropogenic impacts in the Swartkops River for this study. Macroinvertebrate based biomonitoring approaches, including the South African Scoring System version 5 (SASS5); a multimetric approach involving 19 metrics; Chironomidae community assessments and screening of morphological deformities in Chironomidae larvae, were applied at four selected sampling sites to assess environmental water quality in the Swartkops River. Macroinvertebrates were sampled us ing the SASS5 protocols. Chironomidae were mounted and identified as far as practically possible using available keys. Mentum, ligula, mandible, paraligula and antenna in Chironomidae larvae were screened for deformities. Physical and chemical water quality variables were measured at each of the selected sampling sites. All data were subjected to relevant statistical analyses. Of the four sites sampled during the study period, results revealed that water quality at site 1 was the least impacted with highest SASS5 scores, average score per taxa (ASPT) values, richness, diversity, equitability and Ephemeroptera –Plecoptera-Trichoptera (EPT) richness, as well as least incidences of chironomid deformities. Water quality at site 2 was considered the next least impacted with higher SASS5 scores, A SPT values, richness, diversity and equitability, and lower incidences of deformities compared to sites 3 and 4. SASS5 scores and ASPT values revealed that both sites 3 and 4 were critically modified but the multimetric analysis, Chironomidae community assessment and incidences of deformities in Chironomidae larvae indicated that site 3 is the most impacted of the four sampling sites, with least species diversity, richness, equitability and highest incidences of deformities. The study revealed the importance of multicriteria approach to environmental biomonitoring as an integrated water resources management tool, and based on the results, site 3, as the most impacted, could be prioritised for restoration intervention.
- Full Text:
- Date Issued: 2011
- Authors: Odume, Oghenekaro Nelson
- Date: 2011
- Subjects: Water -- Pollution -- South Africa -- Swartkops River Water quality biological assessment -- South Africa -- Swartkops River Environmental monitoring -- South Africa -- Swartkops River Aquatic invertebrates -- Effect of water pollution on -- South Africa -- Swartkops River
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6040 , http://hdl.handle.net/10962/d1006199
- Description: A growing human population accompanied by urbanisation and industrialisation have led to over exploitation and pollution of freshwater resources and have consequently impacted on aquatic ecosystem health. The Swartkops River in the Eastern Cape of South Africa is no exception. It drains a heavily industrialised catchment which has led to deterioration of its water quality due to pollution. Integrated water resources management (IWRM) requires the concurrent sustainable use of water resources and the protection of aquatic ecosystem health. Macroinvertebrates are well known for their ability to reflect the health of the environment in which they live, thus they were used to assess anthropogenic impacts in the Swartkops River for this study. Macroinvertebrate based biomonitoring approaches, including the South African Scoring System version 5 (SASS5); a multimetric approach involving 19 metrics; Chironomidae community assessments and screening of morphological deformities in Chironomidae larvae, were applied at four selected sampling sites to assess environmental water quality in the Swartkops River. Macroinvertebrates were sampled us ing the SASS5 protocols. Chironomidae were mounted and identified as far as practically possible using available keys. Mentum, ligula, mandible, paraligula and antenna in Chironomidae larvae were screened for deformities. Physical and chemical water quality variables were measured at each of the selected sampling sites. All data were subjected to relevant statistical analyses. Of the four sites sampled during the study period, results revealed that water quality at site 1 was the least impacted with highest SASS5 scores, average score per taxa (ASPT) values, richness, diversity, equitability and Ephemeroptera –Plecoptera-Trichoptera (EPT) richness, as well as least incidences of chironomid deformities. Water quality at site 2 was considered the next least impacted with higher SASS5 scores, A SPT values, richness, diversity and equitability, and lower incidences of deformities compared to sites 3 and 4. SASS5 scores and ASPT values revealed that both sites 3 and 4 were critically modified but the multimetric analysis, Chironomidae community assessment and incidences of deformities in Chironomidae larvae indicated that site 3 is the most impacted of the four sampling sites, with least species diversity, richness, equitability and highest incidences of deformities. The study revealed the importance of multicriteria approach to environmental biomonitoring as an integrated water resources management tool, and based on the results, site 3, as the most impacted, could be prioritised for restoration intervention.
- Full Text:
- Date Issued: 2011
A preliminary examination of selected biological links between four Eastern Cape estuaries and the inshore marine environment
- Authors: Vorwerk, Paul D
- Date: 2007
- Subjects: Estuaries -- South Africa -- Eastern Cape Marine fishes -- South Africa -- Eastern Cape Marine ecology -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5747 , http://hdl.handle.net/10962/d1005434
- Description: The coastal transition zone (CTZ), which links the terrestrial and marine environments, has been identified as a region of high biological diversity and elevated production. Results of studies conducted in the northern hemisphere indicate that the links between estuaries and the adjacent marine environment is critical to ecological functioning within the CTZ. This study assessed the influence of selected estuaries with different hydrodynamic characteristics on the adjacent marine environment along the south-eastern coastline of southern Africa. Four estuaries were examined, including two permanently open systems, the fresh water deprived Kariega and fresh water dominated Great Fish, and two temporarily open/closed estuaries (TOCE), the Kasouga and East Kleinemonde. Results of the study indicated that outflow of estuarine water from the Great Fish Estuary contributed to a plume of less saline water being evident within the adjacent marine environment. The plume of water was associated with increased zooplankton biomass and particulate organic matter (POM) and chlorophyll-a concentrations. Adjacent to the Kariega Estuary, no evidence of fresh water outflow into the marine environment was observed. However, in the sea directly opposite the mouth of the estuary an increase in zooplankton abundance and biomass was evident. Results of numerical analyses indicated that the increase in zooplankton abundance observed adjacent to the mouth of both permanently open estuaries could not be attributed to the export of zooplankton from the estuary, but rather the accumulation of marine species within the region. The mechanisms responsible for this accumulation were not determined, but it was thought to be associated with increased food availability in the estuarine frontal zone. A similar, but less dramatic biological response was also observed in the marine environment adjacent to the two TOCEs. It is suggested that the increase in biological activity within these regions could be ascribed to seepage of estuarine or ground water through the sand bar that separates these estuaries from the sea. Results of stable carbon isotope analyses indicated that both the Great Fish and Kariega estuaries exported carbon to the nearshore marine environment. The area influenced by estuarine derived carbon was dependent on the volume of estuarine outflow to the marine environment. Adjacent to the fresh water dominated Great Fish Estuary, estuarine derived carbon was recorded up to 12km from the mouth, while adjacent to the fresh water deprived Kariega, estuarine derived carbon was only evident directly opposite the mouth. The recruitment of macrozooplankton (> 2cm) into the fresh water deprived Kariega Estuary was in the range recorded for other permanently open southern African estuaries with higher fresh water flow rates. This indicates that the mechanisms which allow estuarine dependent larvae to locate and enter estuaries are not related to fresh water inflow. In conclusion, this study has demonstrated that despite their small size relative to European and North American systems, South African permanently open and temporarily open/closed estuaries also influence biological activity within the adjacent nearshore marine environment.
- Full Text:
- Date Issued: 2007
- Authors: Vorwerk, Paul D
- Date: 2007
- Subjects: Estuaries -- South Africa -- Eastern Cape Marine fishes -- South Africa -- Eastern Cape Marine ecology -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5747 , http://hdl.handle.net/10962/d1005434
- Description: The coastal transition zone (CTZ), which links the terrestrial and marine environments, has been identified as a region of high biological diversity and elevated production. Results of studies conducted in the northern hemisphere indicate that the links between estuaries and the adjacent marine environment is critical to ecological functioning within the CTZ. This study assessed the influence of selected estuaries with different hydrodynamic characteristics on the adjacent marine environment along the south-eastern coastline of southern Africa. Four estuaries were examined, including two permanently open systems, the fresh water deprived Kariega and fresh water dominated Great Fish, and two temporarily open/closed estuaries (TOCE), the Kasouga and East Kleinemonde. Results of the study indicated that outflow of estuarine water from the Great Fish Estuary contributed to a plume of less saline water being evident within the adjacent marine environment. The plume of water was associated with increased zooplankton biomass and particulate organic matter (POM) and chlorophyll-a concentrations. Adjacent to the Kariega Estuary, no evidence of fresh water outflow into the marine environment was observed. However, in the sea directly opposite the mouth of the estuary an increase in zooplankton abundance and biomass was evident. Results of numerical analyses indicated that the increase in zooplankton abundance observed adjacent to the mouth of both permanently open estuaries could not be attributed to the export of zooplankton from the estuary, but rather the accumulation of marine species within the region. The mechanisms responsible for this accumulation were not determined, but it was thought to be associated with increased food availability in the estuarine frontal zone. A similar, but less dramatic biological response was also observed in the marine environment adjacent to the two TOCEs. It is suggested that the increase in biological activity within these regions could be ascribed to seepage of estuarine or ground water through the sand bar that separates these estuaries from the sea. Results of stable carbon isotope analyses indicated that both the Great Fish and Kariega estuaries exported carbon to the nearshore marine environment. The area influenced by estuarine derived carbon was dependent on the volume of estuarine outflow to the marine environment. Adjacent to the fresh water dominated Great Fish Estuary, estuarine derived carbon was recorded up to 12km from the mouth, while adjacent to the fresh water deprived Kariega, estuarine derived carbon was only evident directly opposite the mouth. The recruitment of macrozooplankton (> 2cm) into the fresh water deprived Kariega Estuary was in the range recorded for other permanently open southern African estuaries with higher fresh water flow rates. This indicates that the mechanisms which allow estuarine dependent larvae to locate and enter estuaries are not related to fresh water inflow. In conclusion, this study has demonstrated that despite their small size relative to European and North American systems, South African permanently open and temporarily open/closed estuaries also influence biological activity within the adjacent nearshore marine environment.
- Full Text:
- Date Issued: 2007
An analysis of oral literary music texts in isiXhosa
- Authors: Mpola, Mavis Noluthando
- Date: 2007
- Subjects: Xhosa (African people) -- Music , Xhosa (African people) -- Music -- History , Xhosa (African people) -- Folklore , Composers, Black -- South Africa , Hymns, Xhosa , Folk literature, Xhosa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3632 , http://hdl.handle.net/10962/d1012909
- Description: This study examines the relationship between composed songs in isiXhosa and the field of oral literature. In traditional Xhosa cultural settings, poetry and music are forms of communal activity enjoyed by that society. Music and poetry perform a special social role in African society in general, providing a critique of socio-economic and political issues. The research analyses the relationship that exists between traditional poetry, izibongo, and composed songs. It demonstrates that in the same way that izibongo can be analysed in order to appreciate the aesthetic value of an oral literary form, the same can be said of composed isiXhosa music. The art of transmitting oral literature is performance. The traditional izibongo are recited before audiences in the same way. Songs (iingoma) stories (amabali) and traditional poetry (izibongo) all comprise oral literature that is transmitted by word of mouth. Opland (1992: 17) says about this type of literature: “Living as it does in the performance is usually appreciated by crowds of people as sounds uttered by the performer who is present before his/her audience.” Opland (ibid 125) again gives an account of who is both reciter of poems and singer of songs. He gives Mthamo’s testimony thus: “He is a singer… with a reputation of being a poet as well.” The musical texts that will be analysed in this thesis will range from those produced as early as 1917, when Benjamin Tyamzashe wrote his first song, Isithandwa sam (My beloved), up to those produced in 1990 when Makhaya Mjana was commissioned by Lovedale on its 150th anniversary to write Qingqa Lovedale (Stand up Lovedale). The song texts total fifty, by twenty-one composers. The texts will be analysed according to different themes, ranging from themes that are metaphoric, themes about events, themes that depict the culture of the amaXhosa, themes with a message of protest, themes demonstrating the relationship between religion and nature, themes that call for unity among the amaXhosa, and themes that depict the personal circumstances of composers and lullabies. The number of texts from each category will vary depending on the composers’ socio-cultural background when they composed the songs. Comparison will be made with some izibongo to show that composers and writers of izibongo are similar artists and, in the words of Mtuze in Izibongo Zomthonyama (1993) “bathwase ngethongo elinye” (They are spiritually gifted in the same way).
- Full Text:
- Date Issued: 2007
- Authors: Mpola, Mavis Noluthando
- Date: 2007
- Subjects: Xhosa (African people) -- Music , Xhosa (African people) -- Music -- History , Xhosa (African people) -- Folklore , Composers, Black -- South Africa , Hymns, Xhosa , Folk literature, Xhosa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3632 , http://hdl.handle.net/10962/d1012909
- Description: This study examines the relationship between composed songs in isiXhosa and the field of oral literature. In traditional Xhosa cultural settings, poetry and music are forms of communal activity enjoyed by that society. Music and poetry perform a special social role in African society in general, providing a critique of socio-economic and political issues. The research analyses the relationship that exists between traditional poetry, izibongo, and composed songs. It demonstrates that in the same way that izibongo can be analysed in order to appreciate the aesthetic value of an oral literary form, the same can be said of composed isiXhosa music. The art of transmitting oral literature is performance. The traditional izibongo are recited before audiences in the same way. Songs (iingoma) stories (amabali) and traditional poetry (izibongo) all comprise oral literature that is transmitted by word of mouth. Opland (1992: 17) says about this type of literature: “Living as it does in the performance is usually appreciated by crowds of people as sounds uttered by the performer who is present before his/her audience.” Opland (ibid 125) again gives an account of who is both reciter of poems and singer of songs. He gives Mthamo’s testimony thus: “He is a singer… with a reputation of being a poet as well.” The musical texts that will be analysed in this thesis will range from those produced as early as 1917, when Benjamin Tyamzashe wrote his first song, Isithandwa sam (My beloved), up to those produced in 1990 when Makhaya Mjana was commissioned by Lovedale on its 150th anniversary to write Qingqa Lovedale (Stand up Lovedale). The song texts total fifty, by twenty-one composers. The texts will be analysed according to different themes, ranging from themes that are metaphoric, themes about events, themes that depict the culture of the amaXhosa, themes with a message of protest, themes demonstrating the relationship between religion and nature, themes that call for unity among the amaXhosa, and themes that depict the personal circumstances of composers and lullabies. The number of texts from each category will vary depending on the composers’ socio-cultural background when they composed the songs. Comparison will be made with some izibongo to show that composers and writers of izibongo are similar artists and, in the words of Mtuze in Izibongo Zomthonyama (1993) “bathwase ngethongo elinye” (They are spiritually gifted in the same way).
- Full Text:
- Date Issued: 2007
Electrochemical studies of metal-ligand interactions and of metal binding proteins
- Authors: Limson, Janice Leigh
- Date: 1999
- Subjects: Electrochemical analysis , Metals -- Analysis , Proteins -- Analysis , Electrochemistry -- Technique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4551 , http://hdl.handle.net/10962/d1018239
- Description: Electrochemical methods were researched for the analysis of metals, proteins and the identification of metal binding proteins. Adsorptive cathodic stripping voltamrnetry for metal analysis combines the inherent sensitivity of electrochemical techniques with the specificity of ligands for the nonfaradaic preconcentration of analytes at the electrode. The utility of catechol, resorcinol, 4-methylcatechol and 4-t-butylcatechol as ligands was explored for the sensitive analysis of copper, bismuth, cadmium and lead on a mercury film glassy carbon electrode. Metal complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed the highest current responses with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper. The electroanalysis of cysteine and cysteine containing proteins at carbon electrodes are impaired by slow electron transfer rates at carbon electrodes, exhibiting high overpotentials, greater than 1 V vs Ag! Agel. Metallophthalocyanines have been shown to promote the electrocatalysis of cysteine at lowered potentials. Chemical modification of electrodes with appropriate modifiers is a means of incorporating specificity into electroanalysis, with applications in electrocatalysis. A glassy carbon electrode was modified by electrodeposition of cobalt (II) tetrasulphophthalocyanine [Co(II)TSPct to produce a chemically modified glassy carbon electrode (CMGCE). The CoTSPc-CMGCE catalysed the oxidation of cysteine in the pH range 1 to 10. The significance of this electrode is an application for analysis of proteins at biological pH's. A biscyanoruthenium(II) phthalocyanine CMGCE catalysed the oxidation of cysteine at 0.43 V vs Ag/AgCl a significant lowering in the overpotential for the oxidation of cysteine. Metallothionein, a metal binding protein, is believed to be involved in metal homeostasis and detoxification in the peripheral organs of living systems. A method for the quantitative determination of this protein utilising its high cysteine content was presented. At pH 8.4 Tris-HCl buffer, and using a CoTSPc-CMGCE modified by electrodeposition of the modifier, the anodic peaks for the oxidation of metallothionein was observed at 0. 90 V vs Ag/ AgCI. Ferredoxin is a simple iron-sulphur protein. One tenth of its residues are cysteine. Ferredoxin is involved in simple electron transfer processes during photosynthesis and respiration. Electrochemical studies of spinach ferredoxin were conducted at a CoTSPc-CMGCE. Anodic currents for the oxidation of the cysteine fragment of ferredoxin was observed at 0.85 V vs Ag/AgCl in HEPES buffer at pH 7.4, representing a new method for analysis of this protein. Voltammetric studies of its ferric/ferrous transition have shown quasi-reversible waves atE~ -0.62 V vs Ag/AgCl only in the presence of promoters. At a CoTSPc-CMGCE, a cathodic wave attributed to the reduction of Fe(III)/Fe(II) was observed at Epc -0.34 V vs Ag/AgCl. This represents an alternative method for voltammetric studies of the ferric/ferrous transition at significantly lowered potentials. Melatonin, a pineal gland hormone functions m setting and entraining circadian rhythms and in neuroprotection as a free radical scavenger and general antioxidant. Using adsorptive cathodic stripping voltammetry, the binding affinities of melatonin, serotonin and tryptophan for metals, were measured. The results showed that the following metal complexes were formed: aluminium with melatonin, serotonin and tryptophan; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron (III) with melatonin and serotonin; lead with melatonin, tryptophan and serotonin, zinc with melatonin and tryptophan and iron (II) with tryptophan. The studies suggest a further role for melatonin in the reduction of free radical generation and in metal detoxification and may explain the accumulation of aluminium in Alzheimer's disease.
- Full Text:
- Date Issued: 1999
- Authors: Limson, Janice Leigh
- Date: 1999
- Subjects: Electrochemical analysis , Metals -- Analysis , Proteins -- Analysis , Electrochemistry -- Technique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4551 , http://hdl.handle.net/10962/d1018239
- Description: Electrochemical methods were researched for the analysis of metals, proteins and the identification of metal binding proteins. Adsorptive cathodic stripping voltamrnetry for metal analysis combines the inherent sensitivity of electrochemical techniques with the specificity of ligands for the nonfaradaic preconcentration of analytes at the electrode. The utility of catechol, resorcinol, 4-methylcatechol and 4-t-butylcatechol as ligands was explored for the sensitive analysis of copper, bismuth, cadmium and lead on a mercury film glassy carbon electrode. Metal complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed the highest current responses with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper. The electroanalysis of cysteine and cysteine containing proteins at carbon electrodes are impaired by slow electron transfer rates at carbon electrodes, exhibiting high overpotentials, greater than 1 V vs Ag! Agel. Metallophthalocyanines have been shown to promote the electrocatalysis of cysteine at lowered potentials. Chemical modification of electrodes with appropriate modifiers is a means of incorporating specificity into electroanalysis, with applications in electrocatalysis. A glassy carbon electrode was modified by electrodeposition of cobalt (II) tetrasulphophthalocyanine [Co(II)TSPct to produce a chemically modified glassy carbon electrode (CMGCE). The CoTSPc-CMGCE catalysed the oxidation of cysteine in the pH range 1 to 10. The significance of this electrode is an application for analysis of proteins at biological pH's. A biscyanoruthenium(II) phthalocyanine CMGCE catalysed the oxidation of cysteine at 0.43 V vs Ag/AgCl a significant lowering in the overpotential for the oxidation of cysteine. Metallothionein, a metal binding protein, is believed to be involved in metal homeostasis and detoxification in the peripheral organs of living systems. A method for the quantitative determination of this protein utilising its high cysteine content was presented. At pH 8.4 Tris-HCl buffer, and using a CoTSPc-CMGCE modified by electrodeposition of the modifier, the anodic peaks for the oxidation of metallothionein was observed at 0. 90 V vs Ag/ AgCI. Ferredoxin is a simple iron-sulphur protein. One tenth of its residues are cysteine. Ferredoxin is involved in simple electron transfer processes during photosynthesis and respiration. Electrochemical studies of spinach ferredoxin were conducted at a CoTSPc-CMGCE. Anodic currents for the oxidation of the cysteine fragment of ferredoxin was observed at 0.85 V vs Ag/AgCl in HEPES buffer at pH 7.4, representing a new method for analysis of this protein. Voltammetric studies of its ferric/ferrous transition have shown quasi-reversible waves atE~ -0.62 V vs Ag/AgCl only in the presence of promoters. At a CoTSPc-CMGCE, a cathodic wave attributed to the reduction of Fe(III)/Fe(II) was observed at Epc -0.34 V vs Ag/AgCl. This represents an alternative method for voltammetric studies of the ferric/ferrous transition at significantly lowered potentials. Melatonin, a pineal gland hormone functions m setting and entraining circadian rhythms and in neuroprotection as a free radical scavenger and general antioxidant. Using adsorptive cathodic stripping voltammetry, the binding affinities of melatonin, serotonin and tryptophan for metals, were measured. The results showed that the following metal complexes were formed: aluminium with melatonin, serotonin and tryptophan; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron (III) with melatonin and serotonin; lead with melatonin, tryptophan and serotonin, zinc with melatonin and tryptophan and iron (II) with tryptophan. The studies suggest a further role for melatonin in the reduction of free radical generation and in metal detoxification and may explain the accumulation of aluminium in Alzheimer's disease.
- Full Text:
- Date Issued: 1999
A molecular genetic assessment of the population structure and variation in two inshore dolphin genera on the east coast of South Africa
- Smith-Goodwin, Jacqueline Anne
- Authors: Smith-Goodwin, Jacqueline Anne
- Date: 1998
- Subjects: Dolphins -- South Africa Variation (Biology) Dolphins -- Genetics Population genetics Bottlenose dolphin -- South Africa Sousa -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4007 , http://hdl.handle.net/10962/d1004067
- Description: Coastal dolphins on the South African east coast are threatened by degradation and loss of habitat as a result of increasing coastal development, industrial effluent and agricultural runoff. In addition, dolphins off the coast of KwaZulu-Natal have, for more than four decades, been heavily exploited through unchecked incidental capture in shark nets set at 45 beaches. In light of the high rate of mortality and apparent depletion of both species, the persistence of bottlenose (Tursiops truncatus) and humpback (Sousa chinensis) dolphins in that region has been questioned. Genetic variation in south east African dolphin populations was determined as a means of assessing the fitness of the populations and their resilience to demographic disturbances. Furthermore, in order to determine the effects of continued mortality on the KwaZulu-Natal subpopulations, it was necessary to determine whether they are open or closed to immigration from the adjacent East Cape region, which represents a relatively unstressed region, characterised by a lack of shark nets and less intensive coastal activities. Genetic variation and differentiation in the maternal genome was assessed by determining the sequence of the first 400 bases of the mtDNA control region in bottlenose and humpback dolphins from KwaZulu-Natal and the East Cape. Nuclear variation and differentiation was estimated at six microsatellite loci and compared with earlier estimates determined from allozyme electrophoresis. Random amplified polymorphic DNA (RAPD) was assessed as a means of identifying population subdivisions and diagnostic population markers. Both bottlenose and humpback dolphins on the South African east coast are characterised by low nuclear and organellar genetic variation, consistent with a possible genetic bottleneck, the inferred date of which coincides with the onset of the last glacial period. Genetic variation in South African bottlenose dolphins was lower than that reported elsewhere for the species, while an intraspecific comparison supported lower genetic variation in South African humpback dolphins than in humpback dolphins sampled off Hong Kong. An analysis of molecular variance (AMOVA), performed on mtDNA haplotype frequency data indicated, for both species, significant genetic subdivision, concordant with geographic location. The data suggested female bottlenose dolphins demonstrate regional philopatry, displaying limited movement between KwaZulu-Natal and the East Cape. Female humpback dolphins tend towards strict local philopatry, with significant maternal differentiation evident both within and between regional subdivisions. Differentiation in microsatellite allele frequencies was also demonstrated between KwaZulu-Natal and the East Cape for both species, suggesting that the movement of male bottlenose and humpback dolphins may also be restricted. Nonetheless, considerably higher nuclear gene flow estimates suggested that males of both species represent the principal vectors of gene dispersal. The implications of historically low genetic variability and population subdivision in South African dolphins are important in view of the current rate of mortality in KwaZulu-Natal. The persistence of coastal dolphin populations relies on their ability to recover following a bottleneck event. Continued removal of demographically important age-sex classes such as occurs in shark nets, may not only further reduce the genetic variation, but would ultimately deplete dolphin populations in KwaZulu-Natal beyond a sustainable number, resulting in eventual local extinction. The differentiation of the two regions implies that, in the event of local extinction occurring, dolphins, particularly females, from adjacent regions will not readily re-colonise the area. This would result in fragmentation of the south east African populations and ensure reproductive isolation from neighbouring populations on the east African coast.
- Full Text:
- Date Issued: 1998
- Authors: Smith-Goodwin, Jacqueline Anne
- Date: 1998
- Subjects: Dolphins -- South Africa Variation (Biology) Dolphins -- Genetics Population genetics Bottlenose dolphin -- South Africa Sousa -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4007 , http://hdl.handle.net/10962/d1004067
- Description: Coastal dolphins on the South African east coast are threatened by degradation and loss of habitat as a result of increasing coastal development, industrial effluent and agricultural runoff. In addition, dolphins off the coast of KwaZulu-Natal have, for more than four decades, been heavily exploited through unchecked incidental capture in shark nets set at 45 beaches. In light of the high rate of mortality and apparent depletion of both species, the persistence of bottlenose (Tursiops truncatus) and humpback (Sousa chinensis) dolphins in that region has been questioned. Genetic variation in south east African dolphin populations was determined as a means of assessing the fitness of the populations and their resilience to demographic disturbances. Furthermore, in order to determine the effects of continued mortality on the KwaZulu-Natal subpopulations, it was necessary to determine whether they are open or closed to immigration from the adjacent East Cape region, which represents a relatively unstressed region, characterised by a lack of shark nets and less intensive coastal activities. Genetic variation and differentiation in the maternal genome was assessed by determining the sequence of the first 400 bases of the mtDNA control region in bottlenose and humpback dolphins from KwaZulu-Natal and the East Cape. Nuclear variation and differentiation was estimated at six microsatellite loci and compared with earlier estimates determined from allozyme electrophoresis. Random amplified polymorphic DNA (RAPD) was assessed as a means of identifying population subdivisions and diagnostic population markers. Both bottlenose and humpback dolphins on the South African east coast are characterised by low nuclear and organellar genetic variation, consistent with a possible genetic bottleneck, the inferred date of which coincides with the onset of the last glacial period. Genetic variation in South African bottlenose dolphins was lower than that reported elsewhere for the species, while an intraspecific comparison supported lower genetic variation in South African humpback dolphins than in humpback dolphins sampled off Hong Kong. An analysis of molecular variance (AMOVA), performed on mtDNA haplotype frequency data indicated, for both species, significant genetic subdivision, concordant with geographic location. The data suggested female bottlenose dolphins demonstrate regional philopatry, displaying limited movement between KwaZulu-Natal and the East Cape. Female humpback dolphins tend towards strict local philopatry, with significant maternal differentiation evident both within and between regional subdivisions. Differentiation in microsatellite allele frequencies was also demonstrated between KwaZulu-Natal and the East Cape for both species, suggesting that the movement of male bottlenose and humpback dolphins may also be restricted. Nonetheless, considerably higher nuclear gene flow estimates suggested that males of both species represent the principal vectors of gene dispersal. The implications of historically low genetic variability and population subdivision in South African dolphins are important in view of the current rate of mortality in KwaZulu-Natal. The persistence of coastal dolphin populations relies on their ability to recover following a bottleneck event. Continued removal of demographically important age-sex classes such as occurs in shark nets, may not only further reduce the genetic variation, but would ultimately deplete dolphin populations in KwaZulu-Natal beyond a sustainable number, resulting in eventual local extinction. The differentiation of the two regions implies that, in the event of local extinction occurring, dolphins, particularly females, from adjacent regions will not readily re-colonise the area. This would result in fragmentation of the south east African populations and ensure reproductive isolation from neighbouring populations on the east African coast.
- Full Text:
- Date Issued: 1998
The development of a typology of science teachers' views on the nature of science and science practical work: an evaluative pilot study
- Authors: Meiring, Leslie Frank
- Date: 1995
- Subjects: Science -- Study and teaching -- Research Science -- Study and teaching -- South Africa Science teachers -- Attitudes Science -- Philosoph
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1931 , http://hdl.handle.net/10962/d1007607
- Description: Many theories on the nature of science and the nature of learning have been proposed. In particular, two theoretical orientations have been identified as having a decisive impact on activities in the school science classroom, namely "Inductivism" and "Constructivism". Inductivism views observations as objective, facts as constants and knowledge as being obtained from a fixed external reality. The constructivist view sees all knowledge as "reality" reconstructed in the mind of the learner. Each view predisposes certain orientations towards the science curriculum and within it particularly to assessment. It is postulated that teachers' views on science will influence how they teach and assess it. An "inductivist" teacher is more likely to reward certain approved responses from learners whereas a "constructivist" teacher is more likely to attend to learners' unique observations as evidence of their thinking. In this study a questionnaire was developed in an attempt classify science teachers according to their views on the nature of science and learning, and during this process encourage them to reflect on these views. It is hoped that the instrument could measure any changes in teacher's views as a result of the teachers becoming more reflective practitioners over time. Research indicates that the majority of teachers have a predominantly inductivist view of science. The study confirmed the results of other researchers by showing that a majority of non-tertiary science educators could be classified as being strongly inductivist. However, the overall proportion of these teachers was not as high as expected. Of possible concern was the indication that the strongly constructivist group showed very strong inductivist tendencies when assessing written tests which involved pupils' responses to laboratory observations.
- Full Text:
- Date Issued: 1995
- Authors: Meiring, Leslie Frank
- Date: 1995
- Subjects: Science -- Study and teaching -- Research Science -- Study and teaching -- South Africa Science teachers -- Attitudes Science -- Philosoph
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1931 , http://hdl.handle.net/10962/d1007607
- Description: Many theories on the nature of science and the nature of learning have been proposed. In particular, two theoretical orientations have been identified as having a decisive impact on activities in the school science classroom, namely "Inductivism" and "Constructivism". Inductivism views observations as objective, facts as constants and knowledge as being obtained from a fixed external reality. The constructivist view sees all knowledge as "reality" reconstructed in the mind of the learner. Each view predisposes certain orientations towards the science curriculum and within it particularly to assessment. It is postulated that teachers' views on science will influence how they teach and assess it. An "inductivist" teacher is more likely to reward certain approved responses from learners whereas a "constructivist" teacher is more likely to attend to learners' unique observations as evidence of their thinking. In this study a questionnaire was developed in an attempt classify science teachers according to their views on the nature of science and learning, and during this process encourage them to reflect on these views. It is hoped that the instrument could measure any changes in teacher's views as a result of the teachers becoming more reflective practitioners over time. Research indicates that the majority of teachers have a predominantly inductivist view of science. The study confirmed the results of other researchers by showing that a majority of non-tertiary science educators could be classified as being strongly inductivist. However, the overall proportion of these teachers was not as high as expected. Of possible concern was the indication that the strongly constructivist group showed very strong inductivist tendencies when assessing written tests which involved pupils' responses to laboratory observations.
- Full Text:
- Date Issued: 1995
A phenomenological explication of the artistic creative experience of a painter, a writer and a playwright
- Authors: Lambie, Eileen
- Date: 1988
- Subjects: Phenomenology Art -- Philosophy Artists Creation (Literary, artistic, etc.)
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3115 , http://hdl.handle.net/10962/d1004605
- Description: The aim of the thesis was to explore two focus questions using the phenomenological approach. Firstly, what it meant to be an artist for three particular artists; a painter, a writer and a playwright. Secondly, what a general explicitation (after Van Kaam, 1958) of the three subjects' artistic creative experience and working processes revealed in essence. The taped data of the three artists were reduced and explored through a number of phenomenological strategies. This led to the formulation of four essential descriptions for each artist, which were based structurally on Van den Berg's experiential categories in A Different Existence. Thus, the essential descriptions reflect each artist's relationship with his/her world, body, fellow people and time. The final step was the achievement of a general extended description. The major conclusion arising from the phenomenological explication is that art affords a way through which artists are able to live an authentic existence. That is, the body and world of the artist are in harmony and the artist's art roots him in the past, is manifest in the present and indicates the future direction of his work. Another conclusion is that the artist is Janus-faced and this enables him/her to balance subjectivity and objectivity in the Lebenswelt and to communicate what he/she sees to others in a healthy way through art. The artist's relationship with world, body, fellow people and with time, is postulated as being qualitatively richer than that of the nonartist. The two focus questions were successfully answered through the research explication and were validated by two independent judges. The viability of the phenomenological approach in the field of artistic creativity was therefore demonstrated. Suggestions for future research were made, one of which was that more phenomenological research aimed at eliciting specific information on the creation of art works might render more information on the artistic creative process.
- Full Text:
- Date Issued: 1988
- Authors: Lambie, Eileen
- Date: 1988
- Subjects: Phenomenology Art -- Philosophy Artists Creation (Literary, artistic, etc.)
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3115 , http://hdl.handle.net/10962/d1004605
- Description: The aim of the thesis was to explore two focus questions using the phenomenological approach. Firstly, what it meant to be an artist for three particular artists; a painter, a writer and a playwright. Secondly, what a general explicitation (after Van Kaam, 1958) of the three subjects' artistic creative experience and working processes revealed in essence. The taped data of the three artists were reduced and explored through a number of phenomenological strategies. This led to the formulation of four essential descriptions for each artist, which were based structurally on Van den Berg's experiential categories in A Different Existence. Thus, the essential descriptions reflect each artist's relationship with his/her world, body, fellow people and time. The final step was the achievement of a general extended description. The major conclusion arising from the phenomenological explication is that art affords a way through which artists are able to live an authentic existence. That is, the body and world of the artist are in harmony and the artist's art roots him in the past, is manifest in the present and indicates the future direction of his work. Another conclusion is that the artist is Janus-faced and this enables him/her to balance subjectivity and objectivity in the Lebenswelt and to communicate what he/she sees to others in a healthy way through art. The artist's relationship with world, body, fellow people and with time, is postulated as being qualitatively richer than that of the nonartist. The two focus questions were successfully answered through the research explication and were validated by two independent judges. The viability of the phenomenological approach in the field of artistic creativity was therefore demonstrated. Suggestions for future research were made, one of which was that more phenomenological research aimed at eliciting specific information on the creation of art works might render more information on the artistic creative process.
- Full Text:
- Date Issued: 1988
Studies on the gastric proteases in three South African snake species
- Robertson, Sirion Sholto Douglas
- Authors: Robertson, Sirion Sholto Douglas
- Date: 1987
- Subjects: Snakes -- South Africa Proteolytic enzymes Pepsin Pepsinogen
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4063 , http://hdl.handle.net/10962/d1004639
- Description: The pepsinogens and pepsins of cobra, mole snake and puff adder have been studied. The pepsinogens of all three species fall into two distinct groups, here designated PI and PII. At least the latter group, in all cases, shows substantial microheterogeneity. Physicochemical studies suggest that the cobra and puff adder PII groups are more similar to each other than either is to the mole snake PII group. Kinetic studies indicate that, in the cobra and mole snake, the PI and PII pepsins differ in their Arrhenius activation energies. Such difference is smaller, or absent, in the case of the puff adder PI and PII pepsins. These characteristics of the pepsins are assessed in the context of the differences between the oral secretions of the three species studied. The suggestion is advanced that the puff adder's strongly proteolytic venom has influenced certain properties of its gastric proteases.
- Full Text:
- Date Issued: 1987
- Authors: Robertson, Sirion Sholto Douglas
- Date: 1987
- Subjects: Snakes -- South Africa Proteolytic enzymes Pepsin Pepsinogen
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4063 , http://hdl.handle.net/10962/d1004639
- Description: The pepsinogens and pepsins of cobra, mole snake and puff adder have been studied. The pepsinogens of all three species fall into two distinct groups, here designated PI and PII. At least the latter group, in all cases, shows substantial microheterogeneity. Physicochemical studies suggest that the cobra and puff adder PII groups are more similar to each other than either is to the mole snake PII group. Kinetic studies indicate that, in the cobra and mole snake, the PI and PII pepsins differ in their Arrhenius activation energies. Such difference is smaller, or absent, in the case of the puff adder PI and PII pepsins. These characteristics of the pepsins are assessed in the context of the differences between the oral secretions of the three species studied. The suggestion is advanced that the puff adder's strongly proteolytic venom has influenced certain properties of its gastric proteases.
- Full Text:
- Date Issued: 1987
Xhosa narrative : an analysis of the production and linguistic properties of discourse with particular reference to "iintsomi" texts
- Authors: Gough, David Huw
- Date: 1986
- Subjects: Folk literature, Xhosa Xhosa language -- Spoken Xhosa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3564 , http://hdl.handle.net/10962/d1002086
- Description: Although the areas I intend to investigate are rather diverse, what unites them is a concern for the ancient and fascinating question of the relationship between language and thought. Assumptions concerning the latter are surely latent as the basis for any inquiry into language. One of my general purposes is to give some overt orientation to this problem which is all too often simply glossed over. More particularly, I am also concerned with shaping a new approach to Bantu linguistic inquiry in terms of an emphasis on discourse analysis. In the context of the burgeoning of discourse analysis internationally, the field has been seriously neglected in Southern Africa. Studies of discourse are, we believe, vital to advancing our knowledge of inter-ethnic communication and understanding, an area that cannot be ignored in Southern Africa. In more general terms, I hope that this thesis represents a challenge to linguistic inquiry in ways that we have already outlined above. Most importantly, is that while it appears that most South African linguists are satisfied with adopting a rigid monotheoretical approach, I differ, advocating a multitheoretical perspective. This, I believe, allows a greater and more holistic view not only of the 'data' in question but also in terms of the general nature of inquiry, as well as the 'world' it attempts to describe. The body of this thesis is divided into two sections which reflect the two central concerns we have outlined above. Section A, divided into three chapters, is chiefly concerned with the conceptual basis of Xhosa narrative and its linguistic manifestation. In this section we shall find cause to query and to redefine traditional approaches to the linguistic categories manifest in Xhosa narrative. In section B, also divided into three chapters, we shall be concerned with the development of a theory of narrative production with specific reference to intsomi production. In this section we include an in depth criticism of previous approaches to this problem before developing and applying our own theory. There are two appendices attached to this thesis. The first presents certain tables and figures relevant to chapter 4. while the second includes the narrative texts from which we draw our examples. (Introduction, p. 21-22)
- Full Text:
- Date Issued: 1986
- Authors: Gough, David Huw
- Date: 1986
- Subjects: Folk literature, Xhosa Xhosa language -- Spoken Xhosa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3564 , http://hdl.handle.net/10962/d1002086
- Description: Although the areas I intend to investigate are rather diverse, what unites them is a concern for the ancient and fascinating question of the relationship between language and thought. Assumptions concerning the latter are surely latent as the basis for any inquiry into language. One of my general purposes is to give some overt orientation to this problem which is all too often simply glossed over. More particularly, I am also concerned with shaping a new approach to Bantu linguistic inquiry in terms of an emphasis on discourse analysis. In the context of the burgeoning of discourse analysis internationally, the field has been seriously neglected in Southern Africa. Studies of discourse are, we believe, vital to advancing our knowledge of inter-ethnic communication and understanding, an area that cannot be ignored in Southern Africa. In more general terms, I hope that this thesis represents a challenge to linguistic inquiry in ways that we have already outlined above. Most importantly, is that while it appears that most South African linguists are satisfied with adopting a rigid monotheoretical approach, I differ, advocating a multitheoretical perspective. This, I believe, allows a greater and more holistic view not only of the 'data' in question but also in terms of the general nature of inquiry, as well as the 'world' it attempts to describe. The body of this thesis is divided into two sections which reflect the two central concerns we have outlined above. Section A, divided into three chapters, is chiefly concerned with the conceptual basis of Xhosa narrative and its linguistic manifestation. In this section we shall find cause to query and to redefine traditional approaches to the linguistic categories manifest in Xhosa narrative. In section B, also divided into three chapters, we shall be concerned with the development of a theory of narrative production with specific reference to intsomi production. In this section we include an in depth criticism of previous approaches to this problem before developing and applying our own theory. There are two appendices attached to this thesis. The first presents certain tables and figures relevant to chapter 4. while the second includes the narrative texts from which we draw our examples. (Introduction, p. 21-22)
- Full Text:
- Date Issued: 1986
An investigation of the shared experience of children's literature, with particular reference to the teacher reading aloud, in senior primary classes
- Authors: McKellar, David William
- Date: 1983
- Subjects: Reading (Elementary) -- South Africa Teachers -- Training of -- South Africa Children's literature Children -- Books and reading
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1919 , http://hdl.handle.net/10962/d1007401
- Full Text:
- Date Issued: 1983
- Authors: McKellar, David William
- Date: 1983
- Subjects: Reading (Elementary) -- South Africa Teachers -- Training of -- South Africa Children's literature Children -- Books and reading
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1919 , http://hdl.handle.net/10962/d1007401
- Full Text:
- Date Issued: 1983
An investigation of the corporate planning concept in a South African motor manufacturing undertaking
- Authors: Coman, Keith Rawson
- Date: 1980
- Subjects: Business planning -- South Africa , Motor vehicle industry -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1081 , http://hdl.handle.net/10962/d1010583 , Business planning -- South Africa , Motor vehicle industry -- South Africa
- Description: The intention of this dissertation is to attempt to project the theoretical concept of Corporate (or Long-Range) Planning into the reality of one of South Africa's major motor vehicle manufacturing company's task environment. It is a sad fact that there are no universally - applicable practical planning "laws" (as are present within the discipline of, say, Physics) amidst the ever-changing hurly-burly world of modern commerce and industry. Accordingly, there are very real distinctions between distilled Corporate Planning theory, as it is propounded in the many available books and articles, and Corporate Planning practice as actually implemented. This is true largely by virtue of the fact that in the same way as persons differ in their physical and mental make-up, so too do individual companies; even to the extent of acquiring a distinct corporate "personality" of their own. Terms of reference, p. 1.
- Full Text:
- Date Issued: 1980
- Authors: Coman, Keith Rawson
- Date: 1980
- Subjects: Business planning -- South Africa , Motor vehicle industry -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1081 , http://hdl.handle.net/10962/d1010583 , Business planning -- South Africa , Motor vehicle industry -- South Africa
- Description: The intention of this dissertation is to attempt to project the theoretical concept of Corporate (or Long-Range) Planning into the reality of one of South Africa's major motor vehicle manufacturing company's task environment. It is a sad fact that there are no universally - applicable practical planning "laws" (as are present within the discipline of, say, Physics) amidst the ever-changing hurly-burly world of modern commerce and industry. Accordingly, there are very real distinctions between distilled Corporate Planning theory, as it is propounded in the many available books and articles, and Corporate Planning practice as actually implemented. This is true largely by virtue of the fact that in the same way as persons differ in their physical and mental make-up, so too do individual companies; even to the extent of acquiring a distinct corporate "personality" of their own. Terms of reference, p. 1.
- Full Text:
- Date Issued: 1980
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