A case study to explore developing a community of practice to support emergent literacy in preschool children's play
- Authors: Martin, Tamarynd
- Date: 2018
- Subjects: Early childhood education , Children -- Language , Reading (Preschool) , Toddlers -- Books and reading
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10948/31841 , vital:31850
- Description: In South Africa at present, Literacy is a cause for rising concern, with reading and writing competency in primary school being at an all-time low. It is a widespread belief that part of the problem lies with the lack early childhood education. Only 37% of children under the age of five attend an early childhood development centre. Furthermore, South Africa has a shortage of educators, specifically within the domain of early childhood development. With more research being done in the area of literacy, more educators concur that emergent literacy forms the foundation of formal reading and writing later on. This study is a participatory case study, which reflects on the importance of literacy in the early years, showing the belief that pre-formal schooling, specifically emergent literacy, is directly linked to proficiency in reading and writing in formal schooling. This study also highlights how educators in early childhood development can be involved in ongoing reflective interventions through in-service training and communities of practice. This community of practice was developed as a series of focus groups, which met on a weekly basis to discuss and share thoughts, opinions and experiences surrounding emergent literacy in a preschool context. From multiple focus groups, I found that the participants became more confident in sharing their experiences and building upon each other’s ideas and thoughts. The focus groups, not only added to their understanding of emergent literacy, but enthused them and created more of an awareness in their day to day practices.
- Full Text:
- Date Issued: 2018
- Authors: Martin, Tamarynd
- Date: 2018
- Subjects: Early childhood education , Children -- Language , Reading (Preschool) , Toddlers -- Books and reading
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10948/31841 , vital:31850
- Description: In South Africa at present, Literacy is a cause for rising concern, with reading and writing competency in primary school being at an all-time low. It is a widespread belief that part of the problem lies with the lack early childhood education. Only 37% of children under the age of five attend an early childhood development centre. Furthermore, South Africa has a shortage of educators, specifically within the domain of early childhood development. With more research being done in the area of literacy, more educators concur that emergent literacy forms the foundation of formal reading and writing later on. This study is a participatory case study, which reflects on the importance of literacy in the early years, showing the belief that pre-formal schooling, specifically emergent literacy, is directly linked to proficiency in reading and writing in formal schooling. This study also highlights how educators in early childhood development can be involved in ongoing reflective interventions through in-service training and communities of practice. This community of practice was developed as a series of focus groups, which met on a weekly basis to discuss and share thoughts, opinions and experiences surrounding emergent literacy in a preschool context. From multiple focus groups, I found that the participants became more confident in sharing their experiences and building upon each other’s ideas and thoughts. The focus groups, not only added to their understanding of emergent literacy, but enthused them and created more of an awareness in their day to day practices.
- Full Text:
- Date Issued: 2018
A comparison of the aquaculture potential of Clarias gariepinus (Burchell, 1822) and its hybrid with Heterobranchus longifilis valenciennes, 1840 in Southern Africa
- Authors: Oellermann, Lawrence Keith
- Date: 1996
- Subjects: Aquaculture -- South Africa Clarias Clariidae Catfishes -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5246 , http://hdl.handle.net/10962/d1005089
- Description: The aim of this study was to evaluate the aquaculture potential of a hybrid between the two largest African silurid catfish, Heterobranchus longifilis (HL) and Clarias gariepinus (CG) . A morphometric, meristic and karyological study showed that the hybrid shared some of the physical characteristics of both C. gariepinus and H. longifilis, while its chromosome complement and fundamental number (2N = 54, FN = 95), was intermediate between that of H. longifilis (2N = 52, FN = 92) and C. gariepinus (2N = 56, FN = 97). The HLxCG cross could therefore be regarded as a true hybrid. For the characters tested, no morphological or karyological differences were apparent between the HLxCG hybrids produced in West Africa and those produced in southern Africa. In southern Africa, the HL♂xCG♀ cross had higher fertilization and hatching rates than pure strain H. longifilis, C. gariepinus or the reverse cross. There was no difference in the survival of the HL♂xCG♀ hybrid larvae and C. gariepinus larvae up to the onset of exogenous feeding. Pure strain H. longifilis juveniles had a faster growth rate than the H. longifilis ♂ x C. gariepinus ♀ juveniles, but the hybrid always grew at a faster rate than C. gariepinus or the reverse cross. The HL♂xCG♀ cross was consequently chosen as the hybrid with the greatest potential for siluroid aquaculture in southern Africa. The HL♂xCG♀ hybrid showed evidence of partial gonadic, gametic and post-zygotic sterility in both sexes. The hybrid was not completely sterile, as it was artificially induced to spawn, and a small number of viable F₂ hybrid and F₁ hybrid x C. gariepinus larvae were produced. However, in the light of its probable reproductive strategy, it is highly unlikely that the hybrid would pose an ecological risk to the southern African region. The H. longifilis ♂ x C. gariepinus ♀ hybrid was compared to C. gariepinus for selected water quality preferences and tolerances. The hybrid had a wider temperature preference (28 °C to 34 °C) than C. gariepinus (28 °C to 30 °C), but appeared to be more dependent on aerial respiration than C. gariepinus. The air-breathing frequency of hybrid fish began to increase at dissolved oxygen concentrations below 3 .8 mg.ℓ⁻¹, while C. gariepinus only showed an increase in air-breathing frequency at concentrations below 3.0 mg.ℓ¹. The hybrid was more tolerant of un-ionised ammonia (96-hour LC₅₀ = 9.1 mg.ℓ⁻¹) than C. gariepinus (96-hour LC₅₀ = 6.5 mg.ℓ⁻¹), but their 96-hour LC₅₀ salinity tolerances were similar (10.8-11.0 g.ℓ⁻¹). The H. longifilis ♂ x C. gariepinus ♀ hybrid had a higher fillet yield (43.9 %) than C. gariepinus (38.9 %), but the crude protein content and amino acid profile of the two groups were similar. Catfish are traditionally grown in earthen ponds under semi-intensive conditions in southern Africa, at around 4 kg of fish per cubic meter of water (kg.m⁻³). However, the hybrid could tolerate densities of up to 415 kg of fish per cubic metre of water, if the water was exchanged hourly (kg.m⁻³.hr⁻¹), and the density at which yield was optimised was rounded off to 400 kg.m³.hr⁻¹. The high threshold density and water quality tolerances of the H. longifilis ♂ x C. gariepinus ♀ hybrid indicates that it is ideally suited for highly intensive aquaculture. It was concluded that it would be more productive to farm the HL♂xCG♀ hybrid on an intensive basis in southern Africa, than it would be to farm C. gariepinus in the traditional manner.
- Full Text:
- Date Issued: 1996
- Authors: Oellermann, Lawrence Keith
- Date: 1996
- Subjects: Aquaculture -- South Africa Clarias Clariidae Catfishes -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5246 , http://hdl.handle.net/10962/d1005089
- Description: The aim of this study was to evaluate the aquaculture potential of a hybrid between the two largest African silurid catfish, Heterobranchus longifilis (HL) and Clarias gariepinus (CG) . A morphometric, meristic and karyological study showed that the hybrid shared some of the physical characteristics of both C. gariepinus and H. longifilis, while its chromosome complement and fundamental number (2N = 54, FN = 95), was intermediate between that of H. longifilis (2N = 52, FN = 92) and C. gariepinus (2N = 56, FN = 97). The HLxCG cross could therefore be regarded as a true hybrid. For the characters tested, no morphological or karyological differences were apparent between the HLxCG hybrids produced in West Africa and those produced in southern Africa. In southern Africa, the HL♂xCG♀ cross had higher fertilization and hatching rates than pure strain H. longifilis, C. gariepinus or the reverse cross. There was no difference in the survival of the HL♂xCG♀ hybrid larvae and C. gariepinus larvae up to the onset of exogenous feeding. Pure strain H. longifilis juveniles had a faster growth rate than the H. longifilis ♂ x C. gariepinus ♀ juveniles, but the hybrid always grew at a faster rate than C. gariepinus or the reverse cross. The HL♂xCG♀ cross was consequently chosen as the hybrid with the greatest potential for siluroid aquaculture in southern Africa. The HL♂xCG♀ hybrid showed evidence of partial gonadic, gametic and post-zygotic sterility in both sexes. The hybrid was not completely sterile, as it was artificially induced to spawn, and a small number of viable F₂ hybrid and F₁ hybrid x C. gariepinus larvae were produced. However, in the light of its probable reproductive strategy, it is highly unlikely that the hybrid would pose an ecological risk to the southern African region. The H. longifilis ♂ x C. gariepinus ♀ hybrid was compared to C. gariepinus for selected water quality preferences and tolerances. The hybrid had a wider temperature preference (28 °C to 34 °C) than C. gariepinus (28 °C to 30 °C), but appeared to be more dependent on aerial respiration than C. gariepinus. The air-breathing frequency of hybrid fish began to increase at dissolved oxygen concentrations below 3 .8 mg.ℓ⁻¹, while C. gariepinus only showed an increase in air-breathing frequency at concentrations below 3.0 mg.ℓ¹. The hybrid was more tolerant of un-ionised ammonia (96-hour LC₅₀ = 9.1 mg.ℓ⁻¹) than C. gariepinus (96-hour LC₅₀ = 6.5 mg.ℓ⁻¹), but their 96-hour LC₅₀ salinity tolerances were similar (10.8-11.0 g.ℓ⁻¹). The H. longifilis ♂ x C. gariepinus ♀ hybrid had a higher fillet yield (43.9 %) than C. gariepinus (38.9 %), but the crude protein content and amino acid profile of the two groups were similar. Catfish are traditionally grown in earthen ponds under semi-intensive conditions in southern Africa, at around 4 kg of fish per cubic meter of water (kg.m⁻³). However, the hybrid could tolerate densities of up to 415 kg of fish per cubic metre of water, if the water was exchanged hourly (kg.m⁻³.hr⁻¹), and the density at which yield was optimised was rounded off to 400 kg.m³.hr⁻¹. The high threshold density and water quality tolerances of the H. longifilis ♂ x C. gariepinus ♀ hybrid indicates that it is ideally suited for highly intensive aquaculture. It was concluded that it would be more productive to farm the HL♂xCG♀ hybrid on an intensive basis in southern Africa, than it would be to farm C. gariepinus in the traditional manner.
- Full Text:
- Date Issued: 1996
A critical discourse analysis (CDA) of the contesting discourses articulated by the ANC and the news media in the City Press coverage of The Spear
- Authors: Egglestone, Tia Ashleigh
- Date: 2014
- Subjects: Murray, Brett , African National Congress , Mass media -- Political aspects -- South Africa , Press and politics -- South Africa , Freedom of the press -- South Africa , Mass media policy -- South Africa , Newspapers -- Objectivity , Critical discourse analysis , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3526 , http://hdl.handle.net/10962/d1012975
- Description: This research focuses on the controversy surrounding the exhibition and media publication of Brett Murray’s painting, The Spear of the Nation (May 2012). It takes the form of a qualitative Critical Discourse Analysis (CDA), underpinned by Fairclough’s (1995) three-dimensional approach, to investigate how the contesting discourses articulated by the ruling political party (the ANC) and the news media have been negotiated in the City Press coverage in response to the painting. While the contestation was fought ostensibly on constitutional grounds, it arguably serves as an illustrative moment of the deeply ideological debate occurring in South Africa between the government and the national media industry regarding media diversity, transformation and democracy. It points to the lines of fracture in the broader political and social space. Informed by Foucault’s conceptualisation of discourse and the role of power in the production of knowledge and ‘truth’, this study aims to expose the discourses articulated and contested in order to make inferences about the various ‘truths’ the ANC and the media make of the democratic role of the press in a contemporary South Africa. The sample consists of five reports intended to represent the media’s responses and four articles that prominently articulate the ANC’s responses. The analysis, which draws on strategies from within critical linguists and media studies, is confined to these nine purposively sampled from the City Press online newspaper texts published between 13 May 2012 and 13 June 2012. Findings suggest the ANC legitimise expectations for the media to engage in a collaborative role in order to serve the ‘national interest’. Conversely, the media advocate for a monitorial press to justify serving the ‘public interest’. This research is envisioned to be valuable for both sets of stakeholders in developing richer understandings relevant to issues of any regulation to be debated. It forms part of a larger project on Media Policy and Democracy which seeks to contribute to media diversity and transformation, and to develop the quality of democracy in South Africa.
- Full Text:
- Date Issued: 2014
- Authors: Egglestone, Tia Ashleigh
- Date: 2014
- Subjects: Murray, Brett , African National Congress , Mass media -- Political aspects -- South Africa , Press and politics -- South Africa , Freedom of the press -- South Africa , Mass media policy -- South Africa , Newspapers -- Objectivity , Critical discourse analysis , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3526 , http://hdl.handle.net/10962/d1012975
- Description: This research focuses on the controversy surrounding the exhibition and media publication of Brett Murray’s painting, The Spear of the Nation (May 2012). It takes the form of a qualitative Critical Discourse Analysis (CDA), underpinned by Fairclough’s (1995) three-dimensional approach, to investigate how the contesting discourses articulated by the ruling political party (the ANC) and the news media have been negotiated in the City Press coverage in response to the painting. While the contestation was fought ostensibly on constitutional grounds, it arguably serves as an illustrative moment of the deeply ideological debate occurring in South Africa between the government and the national media industry regarding media diversity, transformation and democracy. It points to the lines of fracture in the broader political and social space. Informed by Foucault’s conceptualisation of discourse and the role of power in the production of knowledge and ‘truth’, this study aims to expose the discourses articulated and contested in order to make inferences about the various ‘truths’ the ANC and the media make of the democratic role of the press in a contemporary South Africa. The sample consists of five reports intended to represent the media’s responses and four articles that prominently articulate the ANC’s responses. The analysis, which draws on strategies from within critical linguists and media studies, is confined to these nine purposively sampled from the City Press online newspaper texts published between 13 May 2012 and 13 June 2012. Findings suggest the ANC legitimise expectations for the media to engage in a collaborative role in order to serve the ‘national interest’. Conversely, the media advocate for a monitorial press to justify serving the ‘public interest’. This research is envisioned to be valuable for both sets of stakeholders in developing richer understandings relevant to issues of any regulation to be debated. It forms part of a larger project on Media Policy and Democracy which seeks to contribute to media diversity and transformation, and to develop the quality of democracy in South Africa.
- Full Text:
- Date Issued: 2014
A study of the ecology, behaviour and systematics of Tockus Hornbills
- Authors: Kemp, Alan Charles
- Date: 1973
- Subjects: Birds -- South Africa -- Kruger National Park -- Identification Birds -- South Africa -- Kruger National Park -- Ecology Birds -- South Africa -- Kruger National Park -- Breeding Birds -- Birds -- South Africa -- Kruger National Park -- Nutrition Birds -- South Africa -- Kruger National Park -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5861 , http://hdl.handle.net/10962/d1012634
- Description: During the last decades ecology and behaviour have become of major importance in African ornithology. Not only have more individual species been studied in detail, but behaviour and ecology have been used in a more general sense in regional works (Benson et al 1971} and in zoogeographical treatises (Moreau 1966, Hall and Moreau 1970). As part of a world- wide trend, behaviour and ecology have also become important in systematics and taxonomy eg. Hall's 1963 study of francolin, and Benson et al's 1971 erection of the bush shrike family Malaconotidae. This dissertation fits into this trend, beginning with a detailed study of the ecology and behaviour of three species of hornbill of the genus Tockus, and extending the observations in less detail to five other members of the genus. Combined with the literature, these observations allow an analysis of the systematics and evolution of the genus Tokus to be undertaken, as well as supplying descriptive information on Tokus biology. Intro. p. 1.
- Full Text:
- Date Issued: 1973
- Authors: Kemp, Alan Charles
- Date: 1973
- Subjects: Birds -- South Africa -- Kruger National Park -- Identification Birds -- South Africa -- Kruger National Park -- Ecology Birds -- South Africa -- Kruger National Park -- Breeding Birds -- Birds -- South Africa -- Kruger National Park -- Nutrition Birds -- South Africa -- Kruger National Park -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5861 , http://hdl.handle.net/10962/d1012634
- Description: During the last decades ecology and behaviour have become of major importance in African ornithology. Not only have more individual species been studied in detail, but behaviour and ecology have been used in a more general sense in regional works (Benson et al 1971} and in zoogeographical treatises (Moreau 1966, Hall and Moreau 1970). As part of a world- wide trend, behaviour and ecology have also become important in systematics and taxonomy eg. Hall's 1963 study of francolin, and Benson et al's 1971 erection of the bush shrike family Malaconotidae. This dissertation fits into this trend, beginning with a detailed study of the ecology and behaviour of three species of hornbill of the genus Tockus, and extending the observations in less detail to five other members of the genus. Combined with the literature, these observations allow an analysis of the systematics and evolution of the genus Tokus to be undertaken, as well as supplying descriptive information on Tokus biology. Intro. p. 1.
- Full Text:
- Date Issued: 1973
An investigation into cultural differences in the conceptualization of and attributions about cognitive decline in the elderly
- Authors: Fair, David Alan
- Date: 1999
- Subjects: Dementia , Older people , Dementia Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2974 , http://hdl.handle.net/10962/d1002483 , Dementia , Older people , Dementia Case studies
- Description: There is little data regarding the prevalence of dementia in South Africa. Estimating such prevalence is problematic as the most commonly used cognitive screening tests are inappropriate for use in non-western populations. For this reason researchers have explored the use of informant questionnaires where relatives provide information on cognitive functioning over the last year. In the South African context Lenger, de Villiers & Louw (1996) conducted a dementia case-ascertainment study in a Xhosa-speaking community near Cape Town using a well-known informant questionnaire, the DECO, and concurrent clinical assessment. Reflecting on the discrepancies between DECO scores and clinical diagnosis, the researchers conducted interviews to explore beliefs and expectations regarding the elderly and cognitive decline. The aims of the current research were to gather comparative data from Bothasig, an English-speaking community, in order to explore areas of commonality and difference in perceptions and attributions regarding cognitive decline in the elderly. The study found that a significant percentage of informants from both Bothasig and Langa consider forgetfulness to be normal in old age. Different discourses around illness in the elderly were identified incorporating a range of medicalised and folk attributions. The discussion showed that informant perceptions within the Langa community may increase the likelihood that observational data provided in informant questionnaires may be confounded by cultural perceptions regarding the elderly. In addition, certain items on the DECO were found to be unsuitable for use across groups and modifications were proposed. The data was analyzed using both quantitative methods and phenomenological discourse analysis. The discussion concluded with metatheoretical reflections on the tension between etic and emic perspectives in cross-cultural research.
- Full Text:
- Date Issued: 1999
- Authors: Fair, David Alan
- Date: 1999
- Subjects: Dementia , Older people , Dementia Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2974 , http://hdl.handle.net/10962/d1002483 , Dementia , Older people , Dementia Case studies
- Description: There is little data regarding the prevalence of dementia in South Africa. Estimating such prevalence is problematic as the most commonly used cognitive screening tests are inappropriate for use in non-western populations. For this reason researchers have explored the use of informant questionnaires where relatives provide information on cognitive functioning over the last year. In the South African context Lenger, de Villiers & Louw (1996) conducted a dementia case-ascertainment study in a Xhosa-speaking community near Cape Town using a well-known informant questionnaire, the DECO, and concurrent clinical assessment. Reflecting on the discrepancies between DECO scores and clinical diagnosis, the researchers conducted interviews to explore beliefs and expectations regarding the elderly and cognitive decline. The aims of the current research were to gather comparative data from Bothasig, an English-speaking community, in order to explore areas of commonality and difference in perceptions and attributions regarding cognitive decline in the elderly. The study found that a significant percentage of informants from both Bothasig and Langa consider forgetfulness to be normal in old age. Different discourses around illness in the elderly were identified incorporating a range of medicalised and folk attributions. The discussion showed that informant perceptions within the Langa community may increase the likelihood that observational data provided in informant questionnaires may be confounded by cultural perceptions regarding the elderly. In addition, certain items on the DECO were found to be unsuitable for use across groups and modifications were proposed. The data was analyzed using both quantitative methods and phenomenological discourse analysis. The discussion concluded with metatheoretical reflections on the tension between etic and emic perspectives in cross-cultural research.
- Full Text:
- Date Issued: 1999
An investigation into how Grade 11 Physical Science teachers mediate learning of the topic stoichiometry : a case study
- Authors: Kanime, Mwene Kashiiwandapo
- Date: 2015
- Subjects: Science -- Study and teaching (Secondary) -- Namibia -- Oshikoto , Stoichiometry -- Study and teaching (Secondary) -- Namibia -- Oshikoto , Pedagogical content knowledge , Learning -- Namibia -- Oshikoto , Teacher effectiveness -- Namibia -- Oshikoto
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2035 , http://hdl.handle.net/10962/d1017346
- Description: Stoichiometry is proven to be one of the difficult topics for learners in the NSSC Physical Science syllabus due to its abstract nature. Over the years the Examiner’s reports reveal that learners' performance is very poor in this topic. In addition, learners fear the topic and have developed a negative attitude toward it. It is against this background that I decided to carry out a qualitative case study; investigating how teachers mediate the learning of stoichiometry. The study was conducted at two schools in the Oshikoto Region, Namibia and it involved two grade 11 Physical Science teachers. The study is located within the interpretive paradigm and made use of interviews, document analysis and lesson observations (which were video-taped and transcribed) followed by stimulated recall interviews to generate data. The generated data were analyzed using the inductive approach whereby themes were identified. The themes were later used to develop analytical statements in relation to my research questions and these were used to interpret the data. Moreover, the study adopted the notion of pedagogical content knowledge (PCK) proposed by Shulman (1986, 1987) as well as Vygotsky's (1978) mediation of learning and social constructivism as the theoretical frameworks. The data were validated by triangulation, member checking as well as using the stimulated recall interviews while watching the videos with each participant. The findings of the study show that teachers use several tools to mediate the learning process and this includes the use of language, learners' prior knowledge and analogies. In addition, it emerged in this study that teachers are faced with a number of challenges when mediating learning of this topic. Hence, the study recommends that teachers should develop their pedagogical content knowledge for them to effectively eliminate the challenges faced as well as to come up with the best teaching strategies which they can use to mediate learning and help learners make sense of the topic stoichiometry.
- Full Text:
- Date Issued: 2015
- Authors: Kanime, Mwene Kashiiwandapo
- Date: 2015
- Subjects: Science -- Study and teaching (Secondary) -- Namibia -- Oshikoto , Stoichiometry -- Study and teaching (Secondary) -- Namibia -- Oshikoto , Pedagogical content knowledge , Learning -- Namibia -- Oshikoto , Teacher effectiveness -- Namibia -- Oshikoto
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2035 , http://hdl.handle.net/10962/d1017346
- Description: Stoichiometry is proven to be one of the difficult topics for learners in the NSSC Physical Science syllabus due to its abstract nature. Over the years the Examiner’s reports reveal that learners' performance is very poor in this topic. In addition, learners fear the topic and have developed a negative attitude toward it. It is against this background that I decided to carry out a qualitative case study; investigating how teachers mediate the learning of stoichiometry. The study was conducted at two schools in the Oshikoto Region, Namibia and it involved two grade 11 Physical Science teachers. The study is located within the interpretive paradigm and made use of interviews, document analysis and lesson observations (which were video-taped and transcribed) followed by stimulated recall interviews to generate data. The generated data were analyzed using the inductive approach whereby themes were identified. The themes were later used to develop analytical statements in relation to my research questions and these were used to interpret the data. Moreover, the study adopted the notion of pedagogical content knowledge (PCK) proposed by Shulman (1986, 1987) as well as Vygotsky's (1978) mediation of learning and social constructivism as the theoretical frameworks. The data were validated by triangulation, member checking as well as using the stimulated recall interviews while watching the videos with each participant. The findings of the study show that teachers use several tools to mediate the learning process and this includes the use of language, learners' prior knowledge and analogies. In addition, it emerged in this study that teachers are faced with a number of challenges when mediating learning of this topic. Hence, the study recommends that teachers should develop their pedagogical content knowledge for them to effectively eliminate the challenges faced as well as to come up with the best teaching strategies which they can use to mediate learning and help learners make sense of the topic stoichiometry.
- Full Text:
- Date Issued: 2015
An optimum wind power output model for concentrator augmented wind turbines (CAWTs)
- Authors: Shonhiwa, Chipo
- Date: 2017
- Subjects: Wind power Wind turbines
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8692 , vital:33427
- Description: The aim of this study was to develop an optimum wind power output model for concentrator augmented wind turbines (CAWTs), which can operate in low wind speed areas. This study was done using computational fluid dynamics modelling (CFD), theoretical and experimental work. Currently the wind resource is contributing 2.5percent of the global electricity supply and is anticipated to increase to by 2050. Despite this, the contribution to wind energy consumption share by South Africa is still low having just exceeded in 2015. Like many other countries, South Africa agrees that climate change is one of the biggest challenges currently being faced by mankind and acknowledges that tackling it requires collaborative effort from all. The Integrated Resource Plan (IRP 2010-2030) passed in 2010 targets 26.3percent renewable energy contribution to national energy consumption by the year 2030 with 10.3percent coming from wind energy hence contributing to abatement of climate change. 1518percent 1 000 MW Small wind turbines are known for their vital contribution to providing electricity in remote areas. Their power output is mainly influenced by the turbine rotor diameter and wind speed which depend on tower height. A cost benefit analysis conducted basing on increasing wind speed by increasing the turbine tower height revealed that for small wind turbines, the optimal height is . Concentrator Augmented Wind Turbines (CAWTs) are one of several concepts that have been suggested to increase the power output per unit rotor cross-sectional area by increasing the wind speed upstream of the turbine. Although some research effort has been put in this area, the major drawback is that the effect of concentrator geometry and environmental conditions on the aerodynamics and hence ultimate performance of CAWTs is still not clear. Also, the CAWTs systems that have been made so far, do not track the wind resulting in CAWT systems receiving wind from one direction thus limiting their performance. 25 m Wind has a very low energy density in nature implying that a bigger rotor area is required to harness kinetic energy for generation of meaningful electrical energy. This has resulted in higher costs of producing energy from wind than conventional sources of energy such as fossil fuels and hydro. To lower the cost of wind energy, researchers have come up with several initiatives to boost wind turbine power output. A brief review of various concepts that have been used in this study included: history of wind turbines, South Africa’s political will to abatement of climate change, wind resource assessment, power output augmentation, estimation of air density, historical development of CAWTs, fundamental parameters influencing the performance of CAWTs, mathematical modelling of wind turbines and dynamic similarity. Some facts were borrowed from these concepts to come up with the current study and explain the observations. With a view to assess any concept, it is necessary to study the fundamental basis from which it originates. Thus, it was vital to develop a fundamental basis of CAWT performance from which solutions to currently prevailing questions on the relationships among the governing parameters were obtained. The momentum theory of bare wind turbines, which is also found in literature was described. A similar approach was then used for developing the theory of CAWT systems. The theories of concentrator losses, density variation with weather conditions and turbulence modelling were also described. It was of utmost significance to evaluate the wind power potential of the Western part of the Eastern Cape Province to assess whether there would be a need for the concentrator augmented wind turbines (CAWTs) in the province and all other regions with similar or lower wind speeds in the country. In this study, five-year-long, hourly average wind speed series between January 2009 and December 2013 for six weather stations in the western part of the Eastern Cape (Bisho, Fort Beaufort, Graaff–Reinet, Grahamstown, Port Elizabeth and Queenstown) were statistically analysed using the Weibull distribution function. The dimensionless Weibull shape parameter varied from 1.7 to 2.2. All the values were low indicating that there is widely dispersed data. This means that the data tend to be distributed uniformly over a relatively wide range wind speed. Therefore, this has a positive implication on wind power generation in all the studied areas because if a suitable turbine is installed, it would get enough wind speed to run for the greater part of the year. The scale parameter varied between 3.5 and 6.3. The values for all the sites except Port Elizabeth were relatively low implying that the days of high wind speeds are few. Therefore, wind turbines that require high wind speeds for operation are not suitable here.
- Full Text:
- Date Issued: 2017
- Authors: Shonhiwa, Chipo
- Date: 2017
- Subjects: Wind power Wind turbines
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8692 , vital:33427
- Description: The aim of this study was to develop an optimum wind power output model for concentrator augmented wind turbines (CAWTs), which can operate in low wind speed areas. This study was done using computational fluid dynamics modelling (CFD), theoretical and experimental work. Currently the wind resource is contributing 2.5percent of the global electricity supply and is anticipated to increase to by 2050. Despite this, the contribution to wind energy consumption share by South Africa is still low having just exceeded in 2015. Like many other countries, South Africa agrees that climate change is one of the biggest challenges currently being faced by mankind and acknowledges that tackling it requires collaborative effort from all. The Integrated Resource Plan (IRP 2010-2030) passed in 2010 targets 26.3percent renewable energy contribution to national energy consumption by the year 2030 with 10.3percent coming from wind energy hence contributing to abatement of climate change. 1518percent 1 000 MW Small wind turbines are known for their vital contribution to providing electricity in remote areas. Their power output is mainly influenced by the turbine rotor diameter and wind speed which depend on tower height. A cost benefit analysis conducted basing on increasing wind speed by increasing the turbine tower height revealed that for small wind turbines, the optimal height is . Concentrator Augmented Wind Turbines (CAWTs) are one of several concepts that have been suggested to increase the power output per unit rotor cross-sectional area by increasing the wind speed upstream of the turbine. Although some research effort has been put in this area, the major drawback is that the effect of concentrator geometry and environmental conditions on the aerodynamics and hence ultimate performance of CAWTs is still not clear. Also, the CAWTs systems that have been made so far, do not track the wind resulting in CAWT systems receiving wind from one direction thus limiting their performance. 25 m Wind has a very low energy density in nature implying that a bigger rotor area is required to harness kinetic energy for generation of meaningful electrical energy. This has resulted in higher costs of producing energy from wind than conventional sources of energy such as fossil fuels and hydro. To lower the cost of wind energy, researchers have come up with several initiatives to boost wind turbine power output. A brief review of various concepts that have been used in this study included: history of wind turbines, South Africa’s political will to abatement of climate change, wind resource assessment, power output augmentation, estimation of air density, historical development of CAWTs, fundamental parameters influencing the performance of CAWTs, mathematical modelling of wind turbines and dynamic similarity. Some facts were borrowed from these concepts to come up with the current study and explain the observations. With a view to assess any concept, it is necessary to study the fundamental basis from which it originates. Thus, it was vital to develop a fundamental basis of CAWT performance from which solutions to currently prevailing questions on the relationships among the governing parameters were obtained. The momentum theory of bare wind turbines, which is also found in literature was described. A similar approach was then used for developing the theory of CAWT systems. The theories of concentrator losses, density variation with weather conditions and turbulence modelling were also described. It was of utmost significance to evaluate the wind power potential of the Western part of the Eastern Cape Province to assess whether there would be a need for the concentrator augmented wind turbines (CAWTs) in the province and all other regions with similar or lower wind speeds in the country. In this study, five-year-long, hourly average wind speed series between January 2009 and December 2013 for six weather stations in the western part of the Eastern Cape (Bisho, Fort Beaufort, Graaff–Reinet, Grahamstown, Port Elizabeth and Queenstown) were statistically analysed using the Weibull distribution function. The dimensionless Weibull shape parameter varied from 1.7 to 2.2. All the values were low indicating that there is widely dispersed data. This means that the data tend to be distributed uniformly over a relatively wide range wind speed. Therefore, this has a positive implication on wind power generation in all the studied areas because if a suitable turbine is installed, it would get enough wind speed to run for the greater part of the year. The scale parameter varied between 3.5 and 6.3. The values for all the sites except Port Elizabeth were relatively low implying that the days of high wind speeds are few. Therefore, wind turbines that require high wind speeds for operation are not suitable here.
- Full Text:
- Date Issued: 2017
Aquatic invasions of the Nseleni River system: causes, consequences and control
- Authors: Jones, Roy William
- Date: 2015
- Subjects: Gastropoda -- South Africa , Introduced snails -- South Africa , Introduced mollusks -- South Africa , Loricariidae , Introduced fishes -- South Africa , Water hyacinth , Alien plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5928 , http://hdl.handle.net/10962/d1017806
- Description: Globalization has seen an unprecedented dispersal of exotic and alien species worldwide resulting in worldwide homogenization and sometimes extinction of indigenous or endemic taxa. When an exotic species becomes established in a new habitat the invasive organisms are capable of having an impact on indigenous community dynamics and the overall structure and function of ecosystems. Furthermore, the impact of invasion is determined by the geographical range, abundance and the per-capita or per-biomass effect of the invader. However, the success of the introduced organisms is reliant on their ability to acclimate to the physiochemical conditions of the newly invaded environment.Freshwater ecosystems are especially vulnerable to invasions because there are numerous potential routes of introduction including intentional pathways such as stocking, and unintentional pathways such as the release of ballast water and aquarium releases. Efforts to limit the introduction of invasive species or to manage established exotic populations are often hindered by insufficient understanding of the natural history of problematic species. Relatively little is known regarding the physiological tolerances of many taxa. Knowledge about specific species ecophysiological constraints allows for the prediction of future patterns of invasion more accurately, including where an introduced organism would probably survive, thrive and disperse. Furthermore, data on the physiological tolerances of an introduced exotic organism may provide data necessary for effective management and control. This studyinvestigated three invasive species in the Nseleni River system in a protected area in KwaZulu-Natal. The species studied were, Tarebia granifera (Quilted melania – Lamarck, 1822), Pterygoplichthys disjunctivus (Suckermouth armoured catfish - Weber, 1991) and Eichhornia crassipes (water hyacinth – (Martius) Solms-Laubach,). The Nseleni River flows into Lake Nsezi which is responsible for providing potable water to the surrounding towns and industry, as well as the surrounding rural communities. The Enseleni Nature reserve has become the centre for biodiversity dispersal in the immediate area, due to the change in landscape surrounding the protected area.An important step in developing alien invasive species management strategies in protected areas is determining their extent and invasive traits. Tarebia granifera is a prosobranch gastropod originally from South-East Asia that has become invasive in several countries around the world including South Africa. Snail populations were sampled at nine sites throughout the Nseleni/Mposa river system every six weeks over a twelve month period. The snail was abundant throughout the system, especially in shallow waters of less than 1m in depth.The first positive identification the loricariid catfish Pterygoplichthys disjunctivus for the Nseleni River was in 2006. The original introduction is believed to have been via the aquarium trade. The aim of the study was to assess the usefulness of the unified framework with regard to management of fish invasions by assessing the invasion stage of the loricariid population and identifying appropriate management actions using the Blackburn et al. (2011) framework. The fish were sampled at nine different sites and three different depths over a period of twelve months, as well as when two ichthyological surveys were carried out on the Nseleni River system. This invasive fish has been located throughout the system and both male and female fish were collected. The smallest fish sampled was a fingerling of a day or two old and the smallest pregnant female was a mere 270mm TL. This is a clear indication that this fish is breeding in the river system.Although T. granifera and P. disjunctivus were abundant in the Nseleni/Mposa river system, it was not clear what their role in the system was, and in particular if they were competing with any of the indigenous species. Therefore, isotope samples were collected from numerous taxa over a two week period, with the exception of Pterygoplichthys disjunctivus samples, which were collected over 12 months. The δ13C and δ15N signatures of all samples were determined. The niche overlap between the invasive and indigenous snails was effectively zero (1.02E-13%), indicating no shared food resources. The medium ranges of dNRb (7.14) and dCRb (9.07) for the invasive fish indicate that it utilizes a wider range of food resources and trophic levels than the majority of indigenous fish. A medium CDb value (2.34) for the invasive fish species, P. disjunctivus, describes medium trophic diversity, with three indigenous species possessing higher diversity and three possessing lower diversity. Furtherresults indicated that there was no direct dietary competition between P. disjunctivus and indigenous species. Eichhornia crassipes was first recorded on the Nseleni River in 1978, and has been shown to have a significant negative impact on the biodiversity of the Nseleni/Mposa River system and therefore required a control intervention. Although biological control using the two weevil species Neochetina eichhornia (Warner) and N. bruchi (Hustache) has been credited with affecting a good level of control, the lack of a manipulated post-release evaluation experiments has undermined this statement. Five experimental plots of water hyacinth of 20m2 were sprayed with an insecticide to control weevils. After ten months the plants in the sprayed plots were significantly bigger and heavier than those in the control plots that had natural populations of the biological control agents. This study has shown unequivocally that biological control has contributed significantly to the control of water hyacinth on the Nseleni/Mposa River system.The management plan for the Enseleni Nature Reserve identifies the need to control invasive and/or exotic organisms within the boundary of the protected area. In addition, set guidelines have been implemented on how to control these organisms, so that indigenous organisms are least affected. Lack of control of exotic organisms can have serious consequences for indigenous species. It is therefore of utmost importance that the population dynamics of the invading organism be understood, what the potential impact could be and how to control them. Furthermore, it has also acknowledged the threat of possible exotic species invasions from outside of the protected area that might result in threats to the protected area and that these must be investigated, researched and managed.This thesis has identified Tarebia granifera, Pterygoplichthys disjunctivus and Eichhornia crassipes as being a threat to indigenous biodiversity within the protected area, as well as in adjacent areas to the protected area. The thesis will therefore investigate the hypothesis that both Tarebia granifera and Pterygoplichthys disjunctivus are having a direct negative effect on available food resources for indigenous species of organisms. In addition, this thesis will investigate if theNeochetina species that have previously been introduced onto E. crassipes are having any negative effect on this invasive alien aquatic plant.
- Full Text:
- Date Issued: 2015
- Authors: Jones, Roy William
- Date: 2015
- Subjects: Gastropoda -- South Africa , Introduced snails -- South Africa , Introduced mollusks -- South Africa , Loricariidae , Introduced fishes -- South Africa , Water hyacinth , Alien plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5928 , http://hdl.handle.net/10962/d1017806
- Description: Globalization has seen an unprecedented dispersal of exotic and alien species worldwide resulting in worldwide homogenization and sometimes extinction of indigenous or endemic taxa. When an exotic species becomes established in a new habitat the invasive organisms are capable of having an impact on indigenous community dynamics and the overall structure and function of ecosystems. Furthermore, the impact of invasion is determined by the geographical range, abundance and the per-capita or per-biomass effect of the invader. However, the success of the introduced organisms is reliant on their ability to acclimate to the physiochemical conditions of the newly invaded environment.Freshwater ecosystems are especially vulnerable to invasions because there are numerous potential routes of introduction including intentional pathways such as stocking, and unintentional pathways such as the release of ballast water and aquarium releases. Efforts to limit the introduction of invasive species or to manage established exotic populations are often hindered by insufficient understanding of the natural history of problematic species. Relatively little is known regarding the physiological tolerances of many taxa. Knowledge about specific species ecophysiological constraints allows for the prediction of future patterns of invasion more accurately, including where an introduced organism would probably survive, thrive and disperse. Furthermore, data on the physiological tolerances of an introduced exotic organism may provide data necessary for effective management and control. This studyinvestigated three invasive species in the Nseleni River system in a protected area in KwaZulu-Natal. The species studied were, Tarebia granifera (Quilted melania – Lamarck, 1822), Pterygoplichthys disjunctivus (Suckermouth armoured catfish - Weber, 1991) and Eichhornia crassipes (water hyacinth – (Martius) Solms-Laubach,). The Nseleni River flows into Lake Nsezi which is responsible for providing potable water to the surrounding towns and industry, as well as the surrounding rural communities. The Enseleni Nature reserve has become the centre for biodiversity dispersal in the immediate area, due to the change in landscape surrounding the protected area.An important step in developing alien invasive species management strategies in protected areas is determining their extent and invasive traits. Tarebia granifera is a prosobranch gastropod originally from South-East Asia that has become invasive in several countries around the world including South Africa. Snail populations were sampled at nine sites throughout the Nseleni/Mposa river system every six weeks over a twelve month period. The snail was abundant throughout the system, especially in shallow waters of less than 1m in depth.The first positive identification the loricariid catfish Pterygoplichthys disjunctivus for the Nseleni River was in 2006. The original introduction is believed to have been via the aquarium trade. The aim of the study was to assess the usefulness of the unified framework with regard to management of fish invasions by assessing the invasion stage of the loricariid population and identifying appropriate management actions using the Blackburn et al. (2011) framework. The fish were sampled at nine different sites and three different depths over a period of twelve months, as well as when two ichthyological surveys were carried out on the Nseleni River system. This invasive fish has been located throughout the system and both male and female fish were collected. The smallest fish sampled was a fingerling of a day or two old and the smallest pregnant female was a mere 270mm TL. This is a clear indication that this fish is breeding in the river system.Although T. granifera and P. disjunctivus were abundant in the Nseleni/Mposa river system, it was not clear what their role in the system was, and in particular if they were competing with any of the indigenous species. Therefore, isotope samples were collected from numerous taxa over a two week period, with the exception of Pterygoplichthys disjunctivus samples, which were collected over 12 months. The δ13C and δ15N signatures of all samples were determined. The niche overlap between the invasive and indigenous snails was effectively zero (1.02E-13%), indicating no shared food resources. The medium ranges of dNRb (7.14) and dCRb (9.07) for the invasive fish indicate that it utilizes a wider range of food resources and trophic levels than the majority of indigenous fish. A medium CDb value (2.34) for the invasive fish species, P. disjunctivus, describes medium trophic diversity, with three indigenous species possessing higher diversity and three possessing lower diversity. Furtherresults indicated that there was no direct dietary competition between P. disjunctivus and indigenous species. Eichhornia crassipes was first recorded on the Nseleni River in 1978, and has been shown to have a significant negative impact on the biodiversity of the Nseleni/Mposa River system and therefore required a control intervention. Although biological control using the two weevil species Neochetina eichhornia (Warner) and N. bruchi (Hustache) has been credited with affecting a good level of control, the lack of a manipulated post-release evaluation experiments has undermined this statement. Five experimental plots of water hyacinth of 20m2 were sprayed with an insecticide to control weevils. After ten months the plants in the sprayed plots were significantly bigger and heavier than those in the control plots that had natural populations of the biological control agents. This study has shown unequivocally that biological control has contributed significantly to the control of water hyacinth on the Nseleni/Mposa River system.The management plan for the Enseleni Nature Reserve identifies the need to control invasive and/or exotic organisms within the boundary of the protected area. In addition, set guidelines have been implemented on how to control these organisms, so that indigenous organisms are least affected. Lack of control of exotic organisms can have serious consequences for indigenous species. It is therefore of utmost importance that the population dynamics of the invading organism be understood, what the potential impact could be and how to control them. Furthermore, it has also acknowledged the threat of possible exotic species invasions from outside of the protected area that might result in threats to the protected area and that these must be investigated, researched and managed.This thesis has identified Tarebia granifera, Pterygoplichthys disjunctivus and Eichhornia crassipes as being a threat to indigenous biodiversity within the protected area, as well as in adjacent areas to the protected area. The thesis will therefore investigate the hypothesis that both Tarebia granifera and Pterygoplichthys disjunctivus are having a direct negative effect on available food resources for indigenous species of organisms. In addition, this thesis will investigate if theNeochetina species that have previously been introduced onto E. crassipes are having any negative effect on this invasive alien aquatic plant.
- Full Text:
- Date Issued: 2015
Aspects of the anaerobic digestion of wattle tannins
- Authors: Hurlow, Elton Lloyd
- Date: 1987
- Subjects: Tanneries -- Waste disposal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4300 , http://hdl.handle.net/10962/d1004909
- Description: The aqueous extract from the bark of the black wattle tree, (Acacia mearnsii De Wild)(1), is used extensively in the tanning industry for the production of sole and other heavy leathers as well as in lighter leathers and skins. The commercial extract is available in an easily dissolvable spray dried form and in deference to its genus name Mimosaceae is referred to in the trade as Mimosa(3). Mimosa extract consists primarily of high molecular weight polymeric flavonoid units which also constitutes the active tanning ingredient. Lower phenolics, gums and sugars or the so called "non-tannins" are present as impurities and contribute up to 40% to (3 ) the total mass of the extract.
- Full Text:
- Date Issued: 1987
- Authors: Hurlow, Elton Lloyd
- Date: 1987
- Subjects: Tanneries -- Waste disposal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4300 , http://hdl.handle.net/10962/d1004909
- Description: The aqueous extract from the bark of the black wattle tree, (Acacia mearnsii De Wild)(1), is used extensively in the tanning industry for the production of sole and other heavy leathers as well as in lighter leathers and skins. The commercial extract is available in an easily dissolvable spray dried form and in deference to its genus name Mimosaceae is referred to in the trade as Mimosa(3). Mimosa extract consists primarily of high molecular weight polymeric flavonoid units which also constitutes the active tanning ingredient. Lower phenolics, gums and sugars or the so called "non-tannins" are present as impurities and contribute up to 40% to (3 ) the total mass of the extract.
- Full Text:
- Date Issued: 1987
Assessing farmers’ aspirations and goals to expand irrigation crop production from homestead gardens to irrigation plots in Mhlontlo Local Municipality
- Authors: Finiza, Tabisa Nomava
- Date: 2014
- Subjects: Crops irrigation -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11209 , http://hdl.handle.net/10353/d1016173 , Crops irrigation -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape
- Description: Most land is still state owned and is granted to users through traditional authorities. Even though the government has undertaken some programmes to reduce rural poverty and has initiated land reform programmes, improved service delivery and formed new water rights legislation in rural areas, the problem of low crop production still persists among South African farmers. The study was undertaken to identify different farmers’ aspirations and goals for expanding their crop production from homestead gardening to irrigation plots in Mhlontlo Local Municipality, in the Eastern Cape of South Africa. The central problem is that smallholder farmers are not expanding their scale of crop production even though they have access to natural capital which includes land and water. The broad objective of the study was to determine the aspirations and goals of farmers to expand irrigation crop production from homestead gardens to irrigation plots. The specific objectives of the study were to assess factors that addressed smallholder farmers’ aspirations and goals to expand crop production, to identify challenges that smallholder farmers encountered in expanding from homestead gardens to irrigation plots and to determine the current state of homestead gardens and irrigation plots. A list of 20 goals were identified from the field survey with 54 homestead food gardeners and 50 smallholder irrigation farmers in the different villages of the Mhlontlo Local Municipality. Random sampling was used to select the farmers who were asked to score the identified farm enterprise goals in terms of their relative importance. The goals were categorised into five factors using Gasson goal ranking methods which ranked goals on the basis of intrinsic, expressive, instrumental, and social criteria. The next step was to determine the standard deviations and means of the ranked goals. Descriptive statistics was then used to profile the farmers according to such factors as age, gender, years of farm experience, types of plot, the availability of water and land for crop production, the income farmers generate from the sale of crops produced and these are cross-tabulated with their goal rankings. The Logit model was used to estimate the probability that farmers would belong to a particular goal ranking and performance category. The logit model was also used to identify the factors that influence the expansion of the cropped area. The results revealed that maize production and land size where significant at 1%. Age and type of irrigation used were also positively significant at 1%. The results also revealed that the adoption of agricultural technology by smallholder irrigation farmers and homestead food gardens contributed to better quality produce.
- Full Text:
- Date Issued: 2014
- Authors: Finiza, Tabisa Nomava
- Date: 2014
- Subjects: Crops irrigation -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11209 , http://hdl.handle.net/10353/d1016173 , Crops irrigation -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape
- Description: Most land is still state owned and is granted to users through traditional authorities. Even though the government has undertaken some programmes to reduce rural poverty and has initiated land reform programmes, improved service delivery and formed new water rights legislation in rural areas, the problem of low crop production still persists among South African farmers. The study was undertaken to identify different farmers’ aspirations and goals for expanding their crop production from homestead gardening to irrigation plots in Mhlontlo Local Municipality, in the Eastern Cape of South Africa. The central problem is that smallholder farmers are not expanding their scale of crop production even though they have access to natural capital which includes land and water. The broad objective of the study was to determine the aspirations and goals of farmers to expand irrigation crop production from homestead gardens to irrigation plots. The specific objectives of the study were to assess factors that addressed smallholder farmers’ aspirations and goals to expand crop production, to identify challenges that smallholder farmers encountered in expanding from homestead gardens to irrigation plots and to determine the current state of homestead gardens and irrigation plots. A list of 20 goals were identified from the field survey with 54 homestead food gardeners and 50 smallholder irrigation farmers in the different villages of the Mhlontlo Local Municipality. Random sampling was used to select the farmers who were asked to score the identified farm enterprise goals in terms of their relative importance. The goals were categorised into five factors using Gasson goal ranking methods which ranked goals on the basis of intrinsic, expressive, instrumental, and social criteria. The next step was to determine the standard deviations and means of the ranked goals. Descriptive statistics was then used to profile the farmers according to such factors as age, gender, years of farm experience, types of plot, the availability of water and land for crop production, the income farmers generate from the sale of crops produced and these are cross-tabulated with their goal rankings. The Logit model was used to estimate the probability that farmers would belong to a particular goal ranking and performance category. The logit model was also used to identify the factors that influence the expansion of the cropped area. The results revealed that maize production and land size where significant at 1%. Age and type of irrigation used were also positively significant at 1%. The results also revealed that the adoption of agricultural technology by smallholder irrigation farmers and homestead food gardens contributed to better quality produce.
- Full Text:
- Date Issued: 2014
Assessing the genetic diversity of catface rockcod epinephelus andersoni in the subtropical Western Indian Ocean and modelling the effects of climate change on their distribution
- Authors: Coppinger, Christine Rose
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54499 , vital:26570
- Description: The catface rockcod Epinephelus andersoni is a range-restricted species that is endemic to the southeast coast of Africa from Quissico in Mozambique (subtropical) to Knysna in South Africa (warmtemperate). Its complex life-history, long-lived nature and high residency make E. andersoni potentially vulnerable to over-exploitation. Epinephelus andersoni is an important fishery species and has shown signs of depletion. Due to inadequate information necessary for management and conservation, further research is vital, particularly in the face of potentially significant climatic changes which could put further pressure on E. andersoni. The aim of the study was to provide information for the management of E. andersoni, with considerations for the possibly detrimental effects of future climate change. The objectives of this study were to describe the genetic structure and diversity of E. andersoni and to determine possible range shifts of E. andersoni with future changes in sea surface temperature. Genetic samples were collected throughout the distribution of E. andersoni. Standard DNA extraction and PCR using universal primers were conducted and nuclear (RPS7-1) and mitochondrial (cytochrome b) data were analysed to determine genetic diversity. A combination of nuclear and mitochondrial markers was used to ensure that the results were robust. RPS7-1 haplotype diversity was high (0.801) and an AMOVA on the RPS7-1 data showed significantly high among group variation (ΦCT = 0.204, p < 0.05) between five groups: 1. Quissico to Inhaca; 2. Cape Vidal to Port Edward; 3 Port St Johns to Coffee Bay; 4. Mbashe; 5. Port Alfred. This geographic structuring could be attributed to low gene flow across barriers such as the Port Alfred upwelling cell, the Mozambique Channel eddies and smaller more localised upwelling cells such as the Port St Johns cell. The cytochrome b results contrastingly indicate low haplotype diversity (0.309) and no differentiation (ΦCT = 0.265, p = 0.074) between groups and support the hypothesis of a historical population bottleneck. This may be due to an unusually slower mutation rate of the cytochrome b region than the RPS7-1 region, resulting in the RPS7-1 data showing a more recent picture of diversification. To complement the genetic results, niche modelling techniques were used to determine range shifts of E. andersoni with future temperature trends using species distribution and climatic data. The model illustrated a contraction of the E. andersoni distribution as well as future intensification of various upwelling cells along the south-east African coast including the Port Alfred upwelling cell. Due to the low gene flow across these barriers this intensification could decrease the resilience of E. andersoni, as its range becomes more limited with global change. The genetic data and modelling results combined provide useful information on which to base future fisheries management.
- Full Text:
- Date Issued: 2014
- Authors: Coppinger, Christine Rose
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54499 , vital:26570
- Description: The catface rockcod Epinephelus andersoni is a range-restricted species that is endemic to the southeast coast of Africa from Quissico in Mozambique (subtropical) to Knysna in South Africa (warmtemperate). Its complex life-history, long-lived nature and high residency make E. andersoni potentially vulnerable to over-exploitation. Epinephelus andersoni is an important fishery species and has shown signs of depletion. Due to inadequate information necessary for management and conservation, further research is vital, particularly in the face of potentially significant climatic changes which could put further pressure on E. andersoni. The aim of the study was to provide information for the management of E. andersoni, with considerations for the possibly detrimental effects of future climate change. The objectives of this study were to describe the genetic structure and diversity of E. andersoni and to determine possible range shifts of E. andersoni with future changes in sea surface temperature. Genetic samples were collected throughout the distribution of E. andersoni. Standard DNA extraction and PCR using universal primers were conducted and nuclear (RPS7-1) and mitochondrial (cytochrome b) data were analysed to determine genetic diversity. A combination of nuclear and mitochondrial markers was used to ensure that the results were robust. RPS7-1 haplotype diversity was high (0.801) and an AMOVA on the RPS7-1 data showed significantly high among group variation (ΦCT = 0.204, p < 0.05) between five groups: 1. Quissico to Inhaca; 2. Cape Vidal to Port Edward; 3 Port St Johns to Coffee Bay; 4. Mbashe; 5. Port Alfred. This geographic structuring could be attributed to low gene flow across barriers such as the Port Alfred upwelling cell, the Mozambique Channel eddies and smaller more localised upwelling cells such as the Port St Johns cell. The cytochrome b results contrastingly indicate low haplotype diversity (0.309) and no differentiation (ΦCT = 0.265, p = 0.074) between groups and support the hypothesis of a historical population bottleneck. This may be due to an unusually slower mutation rate of the cytochrome b region than the RPS7-1 region, resulting in the RPS7-1 data showing a more recent picture of diversification. To complement the genetic results, niche modelling techniques were used to determine range shifts of E. andersoni with future temperature trends using species distribution and climatic data. The model illustrated a contraction of the E. andersoni distribution as well as future intensification of various upwelling cells along the south-east African coast including the Port Alfred upwelling cell. Due to the low gene flow across these barriers this intensification could decrease the resilience of E. andersoni, as its range becomes more limited with global change. The genetic data and modelling results combined provide useful information on which to base future fisheries management.
- Full Text:
- Date Issued: 2014
Challenges facing probation officers working with young persons in conflict with the law
- Authors: Volsak, Nobubele
- Date: 2001
- Subjects: Probation officers Probation officers -- Attitudes -- South Africa -- Eastern Cape Juvenile delinquents Probation
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:710 , http://hdl.handle.net/10962/d1006534
- Description: This study aimed at focusing on the challenges facing probation officers working with young persons in conflict with the law, in the Eastern region, which forms part of the Eastern Cape Province. The main purpose of the study was to explore the experiences of probation officers in terms of the legislation that they are using when making decisions pertaining to young persons and the types of programmes that they offer to young persons for diversion and prevention purposes. The researcher also wanted to generate a greater understanding of the resources which probation officers have and need in order to run their programmes successfully to young persons, as well as to explore their feelings about working with young persons. The researcher did some literature review in relation to this field, where it became evident that probation services in respect of young persons in conflict with the law, is a relatively new field of specialisation in South Africa. This field started around 1995 as a result of the Inter - Ministerial Committee (IMC) on young people at risk, which was set up to respond and manage the crisis of more than one thousand children who were released from prisons and police cells. The IMC then, identified probation officers as leading role players in dealing with young persons in conflict with the law. An exploratory (non - experimental) design was used to carry out the research. A qualitative research method was also used as it attempts to describe and explain social reality from the points of view of the participants. This is because the researcher was interested to find out the experiences of probation officers in relation to their work with young persons. A non - probability purposive sample of all (11) probation officers was used. A semi - structured interview schedule with both closed and open - ended questions was used to collect data. All the information gathered from those personal interviews, was analysed by hand because the researcher wanted to interpret and produce social explanations. The findings of this small - scale study have revealed that there are a number of challenges facing probation officers. For example presently there is no comprehensive legislation for the management of young persons caught up in the criminal justice system. Instead, limited provisions are spread throughout a number of separate statutes, which make it difficult for probation officers to apply them. This study has also revealed that there is a shortage of human and material resources, which somehow impact negatively on how probation officers render services to their clientele. All probation officers in this study have positive feelings and attitudes about their work despite the fact that there are some challenges facing them that need to be addressed. Specific recommendations have been made based on the findings of this study, which could contribute to the development of probation services in respect of young persons in conf lict with the law
- Full Text:
- Date Issued: 2001
- Authors: Volsak, Nobubele
- Date: 2001
- Subjects: Probation officers Probation officers -- Attitudes -- South Africa -- Eastern Cape Juvenile delinquents Probation
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:710 , http://hdl.handle.net/10962/d1006534
- Description: This study aimed at focusing on the challenges facing probation officers working with young persons in conflict with the law, in the Eastern region, which forms part of the Eastern Cape Province. The main purpose of the study was to explore the experiences of probation officers in terms of the legislation that they are using when making decisions pertaining to young persons and the types of programmes that they offer to young persons for diversion and prevention purposes. The researcher also wanted to generate a greater understanding of the resources which probation officers have and need in order to run their programmes successfully to young persons, as well as to explore their feelings about working with young persons. The researcher did some literature review in relation to this field, where it became evident that probation services in respect of young persons in conflict with the law, is a relatively new field of specialisation in South Africa. This field started around 1995 as a result of the Inter - Ministerial Committee (IMC) on young people at risk, which was set up to respond and manage the crisis of more than one thousand children who were released from prisons and police cells. The IMC then, identified probation officers as leading role players in dealing with young persons in conflict with the law. An exploratory (non - experimental) design was used to carry out the research. A qualitative research method was also used as it attempts to describe and explain social reality from the points of view of the participants. This is because the researcher was interested to find out the experiences of probation officers in relation to their work with young persons. A non - probability purposive sample of all (11) probation officers was used. A semi - structured interview schedule with both closed and open - ended questions was used to collect data. All the information gathered from those personal interviews, was analysed by hand because the researcher wanted to interpret and produce social explanations. The findings of this small - scale study have revealed that there are a number of challenges facing probation officers. For example presently there is no comprehensive legislation for the management of young persons caught up in the criminal justice system. Instead, limited provisions are spread throughout a number of separate statutes, which make it difficult for probation officers to apply them. This study has also revealed that there is a shortage of human and material resources, which somehow impact negatively on how probation officers render services to their clientele. All probation officers in this study have positive feelings and attitudes about their work despite the fact that there are some challenges facing them that need to be addressed. Specific recommendations have been made based on the findings of this study, which could contribute to the development of probation services in respect of young persons in conf lict with the law
- Full Text:
- Date Issued: 2001
Effects of substance abuse among the youth : the case of Dimbaza Township, King Williams Town Eastern Cape
- Authors: Manyonta, Ayanda
- Date: 2017
- Subjects: Youth -- Substance use -- South Africa -- Eastern Cape Substance abuse -- South Africa -- Eastern Cape Youth -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/9389 , vital:34338
- Description: Youth substance abuse is a major social and health concern globally, South Africa notwithstanding. The effect of using substances among the youth does not only impend overall personal development of the youth, but it also limits their aspiration for the future and creates an environment that exacerbates to social ills. This study explored the effects of substance abuse among the youth in Dimbaza King Williams Town. The study intended to achieve the following specific objectives: (i) to establish the extent of the effects of substance abuse among the youth in Dimbaza township; (ii) determine the impact of the effects of substance abuse towards the development of Dimbaza Township; (iii) document interventional strategies to mitigate the effects of substance abuse. The study used a qualitative approach, where explorative and descriptive designs were used. Specifically, the case study design was used. Data was collected through in-depth interviews, focus groups, secondary data and key informants methods. The study used non-probability sampling techniques, but specifically purpose sampling technique was used. Twenty eight (28) participants were sampled which comprised of (12) youth faced with substance related challenges, (6) family members, and (10) key informants. Data was analyzed qualitatively through content thematic analysis. The study revealed the following: preponderance of marijuana (dagga) and alcohol, peer pressure as precursor to substance abuse, antisocial behaviours attributable to substance abuse, youth engagement in various criminal activities, evidence of moral decay in Dimbaza, state of poverty aggravating substance abuse habits, paucity of community intervention for social ills. The study made the following recommendations: a need for government to intensify awareness of the impact of substance abuse among the youth; the need for social practitioners to mitigate dysfunctional families facing substance related challenges; strategic educational intervention targeting potential addicts are needed so as to curb the proliferation the effect of substance abuse; establishment of family educational programs are needed to capacitate communities in order to mitigating substance related behaviors;; special police force is needed to strengthen substance abuse campaigns as primary intervention so as to educate pre-adolescents about the aftermaths of substance abuse; moral regeneration initiatives are needed to instill the significance of Ubuntu and worth of human being; intensify of moral regeneration campaigns facilitated by faith-based organizations; and lastly, the government and other stakeholders should fund youth development programs that will equip them with skills to afford them opportunities to bolster their lives and contribute to improving their country’s economy.
- Full Text:
- Date Issued: 2017
- Authors: Manyonta, Ayanda
- Date: 2017
- Subjects: Youth -- Substance use -- South Africa -- Eastern Cape Substance abuse -- South Africa -- Eastern Cape Youth -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/9389 , vital:34338
- Description: Youth substance abuse is a major social and health concern globally, South Africa notwithstanding. The effect of using substances among the youth does not only impend overall personal development of the youth, but it also limits their aspiration for the future and creates an environment that exacerbates to social ills. This study explored the effects of substance abuse among the youth in Dimbaza King Williams Town. The study intended to achieve the following specific objectives: (i) to establish the extent of the effects of substance abuse among the youth in Dimbaza township; (ii) determine the impact of the effects of substance abuse towards the development of Dimbaza Township; (iii) document interventional strategies to mitigate the effects of substance abuse. The study used a qualitative approach, where explorative and descriptive designs were used. Specifically, the case study design was used. Data was collected through in-depth interviews, focus groups, secondary data and key informants methods. The study used non-probability sampling techniques, but specifically purpose sampling technique was used. Twenty eight (28) participants were sampled which comprised of (12) youth faced with substance related challenges, (6) family members, and (10) key informants. Data was analyzed qualitatively through content thematic analysis. The study revealed the following: preponderance of marijuana (dagga) and alcohol, peer pressure as precursor to substance abuse, antisocial behaviours attributable to substance abuse, youth engagement in various criminal activities, evidence of moral decay in Dimbaza, state of poverty aggravating substance abuse habits, paucity of community intervention for social ills. The study made the following recommendations: a need for government to intensify awareness of the impact of substance abuse among the youth; the need for social practitioners to mitigate dysfunctional families facing substance related challenges; strategic educational intervention targeting potential addicts are needed so as to curb the proliferation the effect of substance abuse; establishment of family educational programs are needed to capacitate communities in order to mitigating substance related behaviors;; special police force is needed to strengthen substance abuse campaigns as primary intervention so as to educate pre-adolescents about the aftermaths of substance abuse; moral regeneration initiatives are needed to instill the significance of Ubuntu and worth of human being; intensify of moral regeneration campaigns facilitated by faith-based organizations; and lastly, the government and other stakeholders should fund youth development programs that will equip them with skills to afford them opportunities to bolster their lives and contribute to improving their country’s economy.
- Full Text:
- Date Issued: 2017
Exploring how teachers acquire content knowledge of marine and coastal issues to contextualize the natural science curriculum
- Authors: Mbuyazwe, Vuyiswa
- Date: 2011
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:21017 , http://hdl.handle.net/10962/6016
- Description: The transformation process in the South African curriculum has highlighted a need for teachers to change from being passive implementers of curriculum. They are required to interpret the curriculum, adapt materials and develop lesson plans that will be responsive in their own context. They are also required to use materials and mediate learning. This research explores teacher acquisition of content knowledge on marine and coastal issues and probes how teachers work with materials in the development of lesson plans to contextualize the curriculum. A participatory action research process engaged 3 teachers in a contextualizing process of curriculum development. I started to work with the teachers to adapt and re-develop coastal and marine resources to support learning in local context. The research developed in two phases. The first examined existing teacher knowledge of marine and coastal issues and probed how content was integrated into lesson planning. Teachers identified knowledge acquisition as the priority to enable them to work with the materials and curriculum in their context. The second phase set out to enhance teachers’ knowledge of marine and coastal resources through workshops and field trips to improve the adaptation and use of materials. To document these processes and outcomes in the context of this study, I employed a range of data generation strategies including questionnaires, workshops and classroom observations, field notes, focus group discussion and the review of lesson plans, learners’ work and materials used. All participants collaboratively discussed and reflected on the process, but I was responsible for the final interpretation presented here. This study showed that teachers are still entrenched in their normal practice of working with content as facts and definitions, the delivery of abstract propositions that is not aligned with the curriculum goals. The new curriculum required teachers to change their teaching practice by using materials to mediate learning in context. The data revealed a mismatch between teacher practices and what the curriculum required from them.
- Full Text:
- Date Issued: 2011
- Authors: Mbuyazwe, Vuyiswa
- Date: 2011
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:21017 , http://hdl.handle.net/10962/6016
- Description: The transformation process in the South African curriculum has highlighted a need for teachers to change from being passive implementers of curriculum. They are required to interpret the curriculum, adapt materials and develop lesson plans that will be responsive in their own context. They are also required to use materials and mediate learning. This research explores teacher acquisition of content knowledge on marine and coastal issues and probes how teachers work with materials in the development of lesson plans to contextualize the curriculum. A participatory action research process engaged 3 teachers in a contextualizing process of curriculum development. I started to work with the teachers to adapt and re-develop coastal and marine resources to support learning in local context. The research developed in two phases. The first examined existing teacher knowledge of marine and coastal issues and probed how content was integrated into lesson planning. Teachers identified knowledge acquisition as the priority to enable them to work with the materials and curriculum in their context. The second phase set out to enhance teachers’ knowledge of marine and coastal resources through workshops and field trips to improve the adaptation and use of materials. To document these processes and outcomes in the context of this study, I employed a range of data generation strategies including questionnaires, workshops and classroom observations, field notes, focus group discussion and the review of lesson plans, learners’ work and materials used. All participants collaboratively discussed and reflected on the process, but I was responsible for the final interpretation presented here. This study showed that teachers are still entrenched in their normal practice of working with content as facts and definitions, the delivery of abstract propositions that is not aligned with the curriculum goals. The new curriculum required teachers to change their teaching practice by using materials to mediate learning in context. The data revealed a mismatch between teacher practices and what the curriculum required from them.
- Full Text:
- Date Issued: 2011
Historical biogeography of the tribe Platypleurini Schmidt, 1918 (Hemiptera: Cicadidae) with a focus on Southern Africa
- Authors: Price, Benjamin Wills
- Date: 2010
- Subjects: Biogeography -- History -- Africa, Southern Cicadas -- Africa, Southern Cicada (Genus) -- Africa, Southern Biodiversity -- Africa, Southern Cicadas -- Variation -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5708 , http://hdl.handle.net/10962/d1005394
- Description: With our contemporary biota under increasing threat of extinction, it is of interest to understand where, why and how biological diversity is generated. If focussed on appropriate taxa, phylogeographic and phylogenetic studies can assist in the identification of both places and processes central to the origin and maintenance of biological diversity. It is explained why southern Africa presents a perfect test-bed for exploring such mechanisms of diversification and why cicadas (Hemiptera: Cicadidae) have proved very suitable tools for studies of historical biogeography. This study then exemplifies these points by providing the first large-scale investigation of the historical biogeography of the tribe Platypleurini Schmidt, 1918, with emphasis on the genus Platypleura Amyot & Seville, 1843 in southern Africa. Standard methods of DNA sequencing provided data from portions of the mitochondrial small subunit ribosomal 16S RNA (16S) and cytochrome oxidase subunits I (COI) and II (COII); and the nuclear elongation factor 1 alpha (EF-1α) from 400 ethanol-preserved specimens. These data were analysed using standard phylogenetic methods and a time scale of diversification was estimated using a Bayesian framework and both fossil data and DNA substitution rates. The results showed that the tribe is too recent to be of Gondwanan origin. The lack of monophyly of the genera represented in both Asia and Africa showed that the tribe needs formal taxonomic revision. Diversification of the African platypleurine genera coincides with aridification in the early Oligocene. Dispersal of Asian platypleurine taxa coincides with the meeting of Africa and Eurasia in the mid-Oligocene. Two radiations within African Platypleura are hypothesised; one distributed over most of sub-Saharan Africa and the second restricted to southern Africa, with clades restricted within regional biomes. Within each of the three focal biomes, cryptic taxonomic diversity was confirmed, suggesting that, even in relatively well understood groups such as the southern African platypleurine cicadas, molecular data can identify further diversity. Although each focal taxon was restricted to non-overlapping biomes, comparison of the three biomes highlighted interactions between palaeoclimates and fixed landscape features (coastal topography, river catchments and escarpments) as causative agents of vicariance, dispersal, extinction and diversification of these volant insects. The results of using co-distributed species for comparative study cautions against making inferences based on single-taxon datasets and highlights the need to use many, evolutionarily independent taxa when identifying mechanisms of diversification. The dating analyses imply that within-species lineage diversification occurred overwhelmingly within the Pleistocene, a trend that is being increasingly recognised in print for other biota. Some caveats about using phylogenetic approaches to estimate ancestral areas are illustrated. Several recommendations are made regarding additional taxa and data sources for understanding the origin and maintenance of biological diversity.
- Full Text:
- Date Issued: 2010
- Authors: Price, Benjamin Wills
- Date: 2010
- Subjects: Biogeography -- History -- Africa, Southern Cicadas -- Africa, Southern Cicada (Genus) -- Africa, Southern Biodiversity -- Africa, Southern Cicadas -- Variation -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5708 , http://hdl.handle.net/10962/d1005394
- Description: With our contemporary biota under increasing threat of extinction, it is of interest to understand where, why and how biological diversity is generated. If focussed on appropriate taxa, phylogeographic and phylogenetic studies can assist in the identification of both places and processes central to the origin and maintenance of biological diversity. It is explained why southern Africa presents a perfect test-bed for exploring such mechanisms of diversification and why cicadas (Hemiptera: Cicadidae) have proved very suitable tools for studies of historical biogeography. This study then exemplifies these points by providing the first large-scale investigation of the historical biogeography of the tribe Platypleurini Schmidt, 1918, with emphasis on the genus Platypleura Amyot & Seville, 1843 in southern Africa. Standard methods of DNA sequencing provided data from portions of the mitochondrial small subunit ribosomal 16S RNA (16S) and cytochrome oxidase subunits I (COI) and II (COII); and the nuclear elongation factor 1 alpha (EF-1α) from 400 ethanol-preserved specimens. These data were analysed using standard phylogenetic methods and a time scale of diversification was estimated using a Bayesian framework and both fossil data and DNA substitution rates. The results showed that the tribe is too recent to be of Gondwanan origin. The lack of monophyly of the genera represented in both Asia and Africa showed that the tribe needs formal taxonomic revision. Diversification of the African platypleurine genera coincides with aridification in the early Oligocene. Dispersal of Asian platypleurine taxa coincides with the meeting of Africa and Eurasia in the mid-Oligocene. Two radiations within African Platypleura are hypothesised; one distributed over most of sub-Saharan Africa and the second restricted to southern Africa, with clades restricted within regional biomes. Within each of the three focal biomes, cryptic taxonomic diversity was confirmed, suggesting that, even in relatively well understood groups such as the southern African platypleurine cicadas, molecular data can identify further diversity. Although each focal taxon was restricted to non-overlapping biomes, comparison of the three biomes highlighted interactions between palaeoclimates and fixed landscape features (coastal topography, river catchments and escarpments) as causative agents of vicariance, dispersal, extinction and diversification of these volant insects. The results of using co-distributed species for comparative study cautions against making inferences based on single-taxon datasets and highlights the need to use many, evolutionarily independent taxa when identifying mechanisms of diversification. The dating analyses imply that within-species lineage diversification occurred overwhelmingly within the Pleistocene, a trend that is being increasingly recognised in print for other biota. Some caveats about using phylogenetic approaches to estimate ancestral areas are illustrated. Several recommendations are made regarding additional taxa and data sources for understanding the origin and maintenance of biological diversity.
- Full Text:
- Date Issued: 2010
Ichthyofaunal community structures in different types of Eastern Cape estuaries
- Authors: Vorwerk, Paul D
- Date: 2001
- Subjects: Estuarine fishes -- South Africa -- Eastern Cape , Estuarine fishes -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5377 , http://hdl.handle.net/10962/d1016241
- Description: This investigation had three major objectives; firstly to document the estuarine fishes from several poorly studied Eastern Cape estuaries, secondly, to identify similarities and differences in the fish communities from permanently open and intermittently open estuaries, and thirdly, to establish which physico-chemical or environmental variables are responsible for the structuring of these communities. The study area incorporated 10 estuaries along a 70 km long stretch of the Eastern Cape coastline between the towns of Seafield (33° 32' 42" S, 27° 03' 05" E) in the south-east and Hamburg (33° 16' 45" S, 27° 29' 50" E) in the north-west. The systems investigated included two permanently open estuaries and eight intermittently open systems of varying sizes. Overall fish abundance and species richness in the study area revealed no significant seasonal variation. A contrast between open and closed estuaries was evident in the dominance of species from different estuarine dependence categories. Open estuaries comprised mainly category Ib, lla and IIb species, with a high proportion of category IV species. Closed estuaries were dominated by category IIa species, with few category IV species represented. Clear longitudinal trends in relative abundance were demonstrated for individual species. Margalefs species richness index for seine net catches, and a combination of the seine and gill net data, were significantly correlated with catchment size, mean annual runoff, estuarine area and linear length. Fish assemblages in the permanently open and intermittently open estuaries were significantly different (p<0.001) when analysed on a community and density basis. Similarly, the communities in large and small intermittently open estuaries differed significantly on a community (p=0.01) and density basis (p<0.001). These differences where caused by changes in abundance of the dominant estuarine resident and marine migrant species. The environmental variable that was dominant in accounting for these differences was the estuary mouth status. Estuarine resident species had smaller overall body lengths when compared with the marine migrant species. In addition, the estuarine resident species had smaller modal size classes in the closed estuaries when compared with the open estuaries. These differences may be linked to the foraging strategies of the species, as well as food availability and different levels of predation in the different estuary types. The marine migrant species did not show any trends in this respect although the closed systems had the largest individuals for all four dominant marine species. This finding may be linked to the inability of these species to breed in closed estuaries, thus channelling reproductive energy resources into somatic growth. In addition, prolonged periods of mouth closure prevent the emigration of large individuals back to the sea. Otter trawling was conducted in fiye estuaries and captured mostly demersal species. The otter trawl data confirmed the seine net community analysis, with significantly different communities identified in the permanently open and intermittently open estuaries (p=0.02), as well as in the small and large intermittently open estuaries (p=0.03). The environmental variables responsible for these community differences were mouth status and variables associated with estuarine size. The identification of estuary mouth status by this study as the most influential environmental factor is compounded by this "ariable affecting or being indicative of numerous other physico-chemical features. The large differences in the fish communities in different estuary types indicate the importance of each estuary type to various species. This should be taken into account before allowing any form of commercial fishing in these important nursery areas.
- Full Text:
- Date Issued: 2001
- Authors: Vorwerk, Paul D
- Date: 2001
- Subjects: Estuarine fishes -- South Africa -- Eastern Cape , Estuarine fishes -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5377 , http://hdl.handle.net/10962/d1016241
- Description: This investigation had three major objectives; firstly to document the estuarine fishes from several poorly studied Eastern Cape estuaries, secondly, to identify similarities and differences in the fish communities from permanently open and intermittently open estuaries, and thirdly, to establish which physico-chemical or environmental variables are responsible for the structuring of these communities. The study area incorporated 10 estuaries along a 70 km long stretch of the Eastern Cape coastline between the towns of Seafield (33° 32' 42" S, 27° 03' 05" E) in the south-east and Hamburg (33° 16' 45" S, 27° 29' 50" E) in the north-west. The systems investigated included two permanently open estuaries and eight intermittently open systems of varying sizes. Overall fish abundance and species richness in the study area revealed no significant seasonal variation. A contrast between open and closed estuaries was evident in the dominance of species from different estuarine dependence categories. Open estuaries comprised mainly category Ib, lla and IIb species, with a high proportion of category IV species. Closed estuaries were dominated by category IIa species, with few category IV species represented. Clear longitudinal trends in relative abundance were demonstrated for individual species. Margalefs species richness index for seine net catches, and a combination of the seine and gill net data, were significantly correlated with catchment size, mean annual runoff, estuarine area and linear length. Fish assemblages in the permanently open and intermittently open estuaries were significantly different (p<0.001) when analysed on a community and density basis. Similarly, the communities in large and small intermittently open estuaries differed significantly on a community (p=0.01) and density basis (p<0.001). These differences where caused by changes in abundance of the dominant estuarine resident and marine migrant species. The environmental variable that was dominant in accounting for these differences was the estuary mouth status. Estuarine resident species had smaller overall body lengths when compared with the marine migrant species. In addition, the estuarine resident species had smaller modal size classes in the closed estuaries when compared with the open estuaries. These differences may be linked to the foraging strategies of the species, as well as food availability and different levels of predation in the different estuary types. The marine migrant species did not show any trends in this respect although the closed systems had the largest individuals for all four dominant marine species. This finding may be linked to the inability of these species to breed in closed estuaries, thus channelling reproductive energy resources into somatic growth. In addition, prolonged periods of mouth closure prevent the emigration of large individuals back to the sea. Otter trawling was conducted in fiye estuaries and captured mostly demersal species. The otter trawl data confirmed the seine net community analysis, with significantly different communities identified in the permanently open and intermittently open estuaries (p=0.02), as well as in the small and large intermittently open estuaries (p=0.03). The environmental variables responsible for these community differences were mouth status and variables associated with estuarine size. The identification of estuary mouth status by this study as the most influential environmental factor is compounded by this "ariable affecting or being indicative of numerous other physico-chemical features. The large differences in the fish communities in different estuary types indicate the importance of each estuary type to various species. This should be taken into account before allowing any form of commercial fishing in these important nursery areas.
- Full Text:
- Date Issued: 2001
Investigating the role of mycorrhizal fungi and associated bacteria in promoting growth of citrus seedlings
- Authors: Sitole, Phumeza
- Date: 2014
- Subjects: Mycorrhizal fungi , Citrus -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Fungi as biological pest control agents , Bacteria , Phytophthora , Pythium , Indoleacetic acid
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4111 , http://hdl.handle.net/10962/d1013033
- Description: South Africa is the world's second largest exporter of fresh citrus and is ranked 14th in citrus production. Fungal pathogens such as Phytophthora and Pythium cause economic losses as a result of root rot and brown rot. Mycorrhizal fungi are specialized members of the fungal community forming a mutualistic relationship with plant roots. Mycorrhizal fungal structures are known to associate with other soil microorganisms and these may contribute to improved plant growth. A diverse group of bacteria that interact with the mycorrhizal fungi are known as Mycorrhizal Helper Bacteria (MHB). The aim of this study was to investigate the role of arbuscular mycorrhiza and associated bacteria isolated from spores and determine whether they had any plant growth promoting potential. A total of 19 bacteria were isolated from arbuscular mycorrhizal spores and were molecularly identified as belonging to several Bacillus, Micrococcus, Onchrobactrum and Staphylococcus sp. All bacterial isolates were tested for plant growth promotion abilities. One Bacillus isolate was able to solubilise phosphate. Four isolates Micrococcus sp, Micrococcus leteus, Ochrobacterum sp and Ochrobacterum antropi were able to produce Indole Acetic Acid and three isolates showed potential to reduce growth of Phytophthora nicotianae, P. citrocola and P. citrophthora in in vitro plate cultures. Further tests using culture supernatants of the Bacillus sp, Micrococcus sp and Bacillus cereus confirmed their ability to inhibit or reduce growth of the three Phytophthora species in a 96 well bioassay. Bacillus sp and Bacillus cereus were able to inhibit Phytophthora spp by 95 to 100 % and Micrococcus spp was able to decrease pathogen growth by 60 to 94 %. These bacterial isolates were further evaluated for plant growth promoting abilities on citrus rough lemon seedlings alone or in combination with arbuscular mycorrhizal inoculum. Bacterial and mycorrhizal inoculants influence the increase in shoot and root biomass. Bacillus cereus in combination with mycorrhizal inoculum significantly increased seedling shoot to root ratio while root biomass was significantly increased with mycorrhizal inoculation. Due to the short duration of the trial mycorrhizal colonisation could not be assessed. It is evident that selected combinations of bacteria and mycorrhizal fungi could promote citrus seedling growth and potentially improve seedling health. Further studies under nursery conditions are recommended.
- Full Text:
- Date Issued: 2014
- Authors: Sitole, Phumeza
- Date: 2014
- Subjects: Mycorrhizal fungi , Citrus -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Fungi as biological pest control agents , Bacteria , Phytophthora , Pythium , Indoleacetic acid
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4111 , http://hdl.handle.net/10962/d1013033
- Description: South Africa is the world's second largest exporter of fresh citrus and is ranked 14th in citrus production. Fungal pathogens such as Phytophthora and Pythium cause economic losses as a result of root rot and brown rot. Mycorrhizal fungi are specialized members of the fungal community forming a mutualistic relationship with plant roots. Mycorrhizal fungal structures are known to associate with other soil microorganisms and these may contribute to improved plant growth. A diverse group of bacteria that interact with the mycorrhizal fungi are known as Mycorrhizal Helper Bacteria (MHB). The aim of this study was to investigate the role of arbuscular mycorrhiza and associated bacteria isolated from spores and determine whether they had any plant growth promoting potential. A total of 19 bacteria were isolated from arbuscular mycorrhizal spores and were molecularly identified as belonging to several Bacillus, Micrococcus, Onchrobactrum and Staphylococcus sp. All bacterial isolates were tested for plant growth promotion abilities. One Bacillus isolate was able to solubilise phosphate. Four isolates Micrococcus sp, Micrococcus leteus, Ochrobacterum sp and Ochrobacterum antropi were able to produce Indole Acetic Acid and three isolates showed potential to reduce growth of Phytophthora nicotianae, P. citrocola and P. citrophthora in in vitro plate cultures. Further tests using culture supernatants of the Bacillus sp, Micrococcus sp and Bacillus cereus confirmed their ability to inhibit or reduce growth of the three Phytophthora species in a 96 well bioassay. Bacillus sp and Bacillus cereus were able to inhibit Phytophthora spp by 95 to 100 % and Micrococcus spp was able to decrease pathogen growth by 60 to 94 %. These bacterial isolates were further evaluated for plant growth promoting abilities on citrus rough lemon seedlings alone or in combination with arbuscular mycorrhizal inoculum. Bacterial and mycorrhizal inoculants influence the increase in shoot and root biomass. Bacillus cereus in combination with mycorrhizal inoculum significantly increased seedling shoot to root ratio while root biomass was significantly increased with mycorrhizal inoculation. Due to the short duration of the trial mycorrhizal colonisation could not be assessed. It is evident that selected combinations of bacteria and mycorrhizal fungi could promote citrus seedling growth and potentially improve seedling health. Further studies under nursery conditions are recommended.
- Full Text:
- Date Issued: 2014
Investigating the use of Arbuscular Mycorrhizas and Plant Growth Promoting Bacteria to improve the drought tolerance of maize (Zea mays L.)
- Authors: Moore, Nicolle Maureen
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54587 , vital:26591
- Description: Maize (Zea mays L.) is a direct staple food crop in Africa and remains an essential component of global food security, with maize crops accounting for over 60% of the total harvested area of annual food crops. Stress caused by drought and high soil salinity limits crop growth and productivity more than any other single environmental factor, with grain yield reductions up to 76% depending on the severity of the drought and the plant growth stage. Arbuscular mycorrhizal (AM) fungi and Plant Growth Promotion Rhizobacteria (PGPR) have previously been shown to improve tolerance of plants to drought stress through a number of chemical and physiological processes. The aim of this investigation was to determine whether mycorrhizal fungi and rhizobacteria adapted to drought and saline conditions and possessing plant growth promoting (PGP) traits were able to stimulate plant growth responses when applied to Zea mays seeds growing under greenhouse conditions Bacterial isolates selected were tolerant to concentrations of NaCl up to 600 mM and maintained 50% growth at low water potentials (-1.44 MPa). They were positive for Indole Acetic Acid (IAA) production, phosphate solubilisation and secretion of siderophores. Bacterial isolates showing plant growth promoting potential were identified using 16S rDNA gene sequencing as Achromobacter xylosoxidans strains A8 and C54 and Klebsiella oxytoca strain M1. Mixed inoculum was prepared from indigenous communities of mycorrhizas in soils sampled from the Cerebos Salt Pan and the Kalahari Desert. Mycorrhizal diversity was investigated using 454-Pyrosequencing which revealed that the community composition was dominated by species in the Ambispora, Glomus and Paraglomus genera with a rare component represented by species in the Redeckera, Archaeospora and Geosiphon genera. Microscopic examination of plant roots at the end of the trial revealed the presence of diagnostic mycorrhizal structures within the root cells, confirming that colonization was successful. Plant growth response to microbial inoculation was assessed by monitoring changes in plant photosynthetic capacity over the duration of a 7 week pot trial. A significant difference in photosynthetic and biomass data was observed between drought and well-watered groups but no mycorrhizal or bacterial treatment effect was evident within the groups, despite the high levels of colonization by mycorrhizas. These results suggest that the beneficial effects of mycorrhizal colonization may be primarily attributed to improved nutrient and mineral uptake in conditions where nutrients are limiting, resulting in improved growth. The improved growth may then have secondary effects on the plant‟s ability to withstand drought. Having controlled for nutrient deficiency, it was not evident in this study that mycorrhizal fungi were able to stimulate a change in plant physiology and confer drought tolerance under the conditions imposed.
- Full Text:
- Date Issued: 2016
- Authors: Moore, Nicolle Maureen
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54587 , vital:26591
- Description: Maize (Zea mays L.) is a direct staple food crop in Africa and remains an essential component of global food security, with maize crops accounting for over 60% of the total harvested area of annual food crops. Stress caused by drought and high soil salinity limits crop growth and productivity more than any other single environmental factor, with grain yield reductions up to 76% depending on the severity of the drought and the plant growth stage. Arbuscular mycorrhizal (AM) fungi and Plant Growth Promotion Rhizobacteria (PGPR) have previously been shown to improve tolerance of plants to drought stress through a number of chemical and physiological processes. The aim of this investigation was to determine whether mycorrhizal fungi and rhizobacteria adapted to drought and saline conditions and possessing plant growth promoting (PGP) traits were able to stimulate plant growth responses when applied to Zea mays seeds growing under greenhouse conditions Bacterial isolates selected were tolerant to concentrations of NaCl up to 600 mM and maintained 50% growth at low water potentials (-1.44 MPa). They were positive for Indole Acetic Acid (IAA) production, phosphate solubilisation and secretion of siderophores. Bacterial isolates showing plant growth promoting potential were identified using 16S rDNA gene sequencing as Achromobacter xylosoxidans strains A8 and C54 and Klebsiella oxytoca strain M1. Mixed inoculum was prepared from indigenous communities of mycorrhizas in soils sampled from the Cerebos Salt Pan and the Kalahari Desert. Mycorrhizal diversity was investigated using 454-Pyrosequencing which revealed that the community composition was dominated by species in the Ambispora, Glomus and Paraglomus genera with a rare component represented by species in the Redeckera, Archaeospora and Geosiphon genera. Microscopic examination of plant roots at the end of the trial revealed the presence of diagnostic mycorrhizal structures within the root cells, confirming that colonization was successful. Plant growth response to microbial inoculation was assessed by monitoring changes in plant photosynthetic capacity over the duration of a 7 week pot trial. A significant difference in photosynthetic and biomass data was observed between drought and well-watered groups but no mycorrhizal or bacterial treatment effect was evident within the groups, despite the high levels of colonization by mycorrhizas. These results suggest that the beneficial effects of mycorrhizal colonization may be primarily attributed to improved nutrient and mineral uptake in conditions where nutrients are limiting, resulting in improved growth. The improved growth may then have secondary effects on the plant‟s ability to withstand drought. Having controlled for nutrient deficiency, it was not evident in this study that mycorrhizal fungi were able to stimulate a change in plant physiology and confer drought tolerance under the conditions imposed.
- Full Text:
- Date Issued: 2016
Investigation of Sexual Relationships among gay students at the University Of Fort Hare (Alice Campus), Eastern Cape.
- Authors: Mbanga , T.Q
- Date: 2019
- Subjects: Gay youth Sex (Psychology)
- Language: English
- Type: Thesis , Masters , MSoc. Sci (Psychology)
- Identifier: http://hdl.handle.net/10353/17619 , vital:41129
- Description: The main aim of the study was to investigate sexual relationships among gay students at the University of Fort Hare (Alice Campus), Eastern Cape. A qualitative research design was followed and semi-structured interview schedules were issued to twelve participants. The queer theory underpinned this study and it is based on the notion that individuals are able to determine their sexual identity and sexual orientation as they are. The participants, aged 18-25 years, were purposively selected to share their sexual behaviour as gays. The ethical principles such as informed consent, confidentiality, privacy and protection from harm, were adhered to, throughout the study. Prior identification of the themes, coding took place. The following themes were very important in the research and they helped to achieve the aim of the study and they are; challenges gay students experience in their relationships, closet partners, social networks sexual partners among gay students, condom use among gay students, sexual agreements among gay students, condom use, condom self-efficacy, honesty and communication, social support, self-esteem, liberal community and non-homophobic, traditional male circumcision, sexual agreements among gay students ,pornography viewing , sexual abuse among gay students, discrimination in residence, religiosity and perception towards marriage among gay students. Based on the findings, it is recommended that there should be communication among gay couples to avoid lot of conflicts. Also, there should be education about homosexuality in communities, schools and tertiary institutions as many people treat gays badly owing to lack of knowledge
- Full Text:
- Date Issued: 2019
- Authors: Mbanga , T.Q
- Date: 2019
- Subjects: Gay youth Sex (Psychology)
- Language: English
- Type: Thesis , Masters , MSoc. Sci (Psychology)
- Identifier: http://hdl.handle.net/10353/17619 , vital:41129
- Description: The main aim of the study was to investigate sexual relationships among gay students at the University of Fort Hare (Alice Campus), Eastern Cape. A qualitative research design was followed and semi-structured interview schedules were issued to twelve participants. The queer theory underpinned this study and it is based on the notion that individuals are able to determine their sexual identity and sexual orientation as they are. The participants, aged 18-25 years, were purposively selected to share their sexual behaviour as gays. The ethical principles such as informed consent, confidentiality, privacy and protection from harm, were adhered to, throughout the study. Prior identification of the themes, coding took place. The following themes were very important in the research and they helped to achieve the aim of the study and they are; challenges gay students experience in their relationships, closet partners, social networks sexual partners among gay students, condom use among gay students, sexual agreements among gay students, condom use, condom self-efficacy, honesty and communication, social support, self-esteem, liberal community and non-homophobic, traditional male circumcision, sexual agreements among gay students ,pornography viewing , sexual abuse among gay students, discrimination in residence, religiosity and perception towards marriage among gay students. Based on the findings, it is recommended that there should be communication among gay couples to avoid lot of conflicts. Also, there should be education about homosexuality in communities, schools and tertiary institutions as many people treat gays badly owing to lack of knowledge
- Full Text:
- Date Issued: 2019
Learners' views regarding their effective participation in school governance
- Authors: Munikwa, Julius
- Date: 2016
- Subjects: Student participation in administration
- Language: English
- Type: Thesis , Masters , Education
- Identifier: http://hdl.handle.net/10353/16013 , vital:40582
- Description: Effective learner participation for the development of Representative Council of Learners (RCL) governors in school governance (SG) is of great essence. A qualitative study was conducted in order to assess the learners’ views regarding their lived views and experiences in SG. Twenty four (24) RCL and class representatives from three data sites comprising three high schools in East Cape, in the East London District Education participated in the study. Data was gathered through semi-structured interviews, focus group discussions and document analysis from two convenient and one snowball samples, respectively. From each school, a chairperson, a secretary and six focus group discussions (FDGs) members were utilised as participants in order to enrich the study. In doing so, the study made use of Wilcox’s ladder of participation as the lens to unpack the learners’ views regarding their effective participation in school governance. This ladder includes information, consultation, deciding together, acting together and supporting independent community interests. The findings showed that learner participation in both township and former Model C schools is significant. However, a number of pertinent factors that make the voices of learner governors to be stifled emerged. These include lack of capacity building, exclusion from other meetings, dominance of adult governors, lack of collaboration and the fact that learners have to be seen as being respectful and disciplined when in meetings with parents. This makes them to accept their role as a tool for middlemen between the parents, teachers and fellow students. These make the field of effective learner participation uneven, hence making them window dressers and have pseudo contributions in SG. The study therefore suggested that learners should be capacitated to make effective and meaningful contribution in school governance. Learners should work collaboratively with adult governors to enhance effective participation in SG.
- Full Text:
- Date Issued: 2016
- Authors: Munikwa, Julius
- Date: 2016
- Subjects: Student participation in administration
- Language: English
- Type: Thesis , Masters , Education
- Identifier: http://hdl.handle.net/10353/16013 , vital:40582
- Description: Effective learner participation for the development of Representative Council of Learners (RCL) governors in school governance (SG) is of great essence. A qualitative study was conducted in order to assess the learners’ views regarding their lived views and experiences in SG. Twenty four (24) RCL and class representatives from three data sites comprising three high schools in East Cape, in the East London District Education participated in the study. Data was gathered through semi-structured interviews, focus group discussions and document analysis from two convenient and one snowball samples, respectively. From each school, a chairperson, a secretary and six focus group discussions (FDGs) members were utilised as participants in order to enrich the study. In doing so, the study made use of Wilcox’s ladder of participation as the lens to unpack the learners’ views regarding their effective participation in school governance. This ladder includes information, consultation, deciding together, acting together and supporting independent community interests. The findings showed that learner participation in both township and former Model C schools is significant. However, a number of pertinent factors that make the voices of learner governors to be stifled emerged. These include lack of capacity building, exclusion from other meetings, dominance of adult governors, lack of collaboration and the fact that learners have to be seen as being respectful and disciplined when in meetings with parents. This makes them to accept their role as a tool for middlemen between the parents, teachers and fellow students. These make the field of effective learner participation uneven, hence making them window dressers and have pseudo contributions in SG. The study therefore suggested that learners should be capacitated to make effective and meaningful contribution in school governance. Learners should work collaboratively with adult governors to enhance effective participation in SG.
- Full Text:
- Date Issued: 2016