Use of eco-art education in supporting the establishment of sustainability competencies in basic education: an interventionist case study
- Authors: Da Silva, Juliana Schmidt
- Date: 2020
- Subjects: Environment (Art) , Environmental education -- Brazil , Sustainable development -- Brazil , Education -- Curricula -- Brazil , Eco-art education
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/166127 , vital:41331
- Description: Recent socioecological approaches in Environmental Education acknowledge the complexity of “real-world situations”, which include environmental problems. One response to the challenge of enabling people to develop sustainability is the key competencies in sustainability framework. It can be faced as a guide to planning Environmental Education actions. On the other side, art practices hold potential to expand learning in varied ways. Art can offer the strategies employed in learning processes directed to sustainability, constituting the field of eco-art education. This research aims to investigate the integration of the visions of the key competencies in sustainability and the eco-art education in an Environmental Education project at high school level. Horta and Gastronomia (Vegetable Garden and Gastronomy) is an extra-curricular activity which happens every year at Irmão Jaime Biazus high school in Porto Alegre, Brazil. It addresses food security and sustainability associating the garden, the kitchen and exploration of sustainability issues using eco-art strategies. Action research approach is used, defining two research cycles to explore the effectiveness of eco-art for the development of key competencies in sustainability. The first cycle focuses on the eco-art activities applied in Horta and Gastronomia (2017 group) while the second cycle deals with a post-project intervention designed to observe indicators of the sustainability competencies and further explore eco-art strategies. This study adds to the field of sustainability competencies by exploring teaching strategies through eco-art education. Insight into key competencies in sustainability is given by presenting the investigation of the group of students about a situation of their reality. The activities implemented, classified according to their objectives, are contextualized regarding the competencies and in learning sequences. This research also contributes to the development of the sustainability competencies framework by applying the theory to a basic education level, adapting the work originally proposed to higher education contexts.
- Full Text:
- Date Issued: 2020
- Authors: Da Silva, Juliana Schmidt
- Date: 2020
- Subjects: Environment (Art) , Environmental education -- Brazil , Sustainable development -- Brazil , Education -- Curricula -- Brazil , Eco-art education
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/166127 , vital:41331
- Description: Recent socioecological approaches in Environmental Education acknowledge the complexity of “real-world situations”, which include environmental problems. One response to the challenge of enabling people to develop sustainability is the key competencies in sustainability framework. It can be faced as a guide to planning Environmental Education actions. On the other side, art practices hold potential to expand learning in varied ways. Art can offer the strategies employed in learning processes directed to sustainability, constituting the field of eco-art education. This research aims to investigate the integration of the visions of the key competencies in sustainability and the eco-art education in an Environmental Education project at high school level. Horta and Gastronomia (Vegetable Garden and Gastronomy) is an extra-curricular activity which happens every year at Irmão Jaime Biazus high school in Porto Alegre, Brazil. It addresses food security and sustainability associating the garden, the kitchen and exploration of sustainability issues using eco-art strategies. Action research approach is used, defining two research cycles to explore the effectiveness of eco-art for the development of key competencies in sustainability. The first cycle focuses on the eco-art activities applied in Horta and Gastronomia (2017 group) while the second cycle deals with a post-project intervention designed to observe indicators of the sustainability competencies and further explore eco-art strategies. This study adds to the field of sustainability competencies by exploring teaching strategies through eco-art education. Insight into key competencies in sustainability is given by presenting the investigation of the group of students about a situation of their reality. The activities implemented, classified according to their objectives, are contextualized regarding the competencies and in learning sequences. This research also contributes to the development of the sustainability competencies framework by applying the theory to a basic education level, adapting the work originally proposed to higher education contexts.
- Full Text:
- Date Issued: 2020
Leadership development within a Learner Representative Council (LRC) in a rural secondary school in the Oshana region, Namibia
- Authors: Da Silva, Rolens
- Date: 2018
- Subjects: Student participation in administration Namibia , Student government Namibia , Educational leadership Namibia , Qualitative research
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62808 , vital:28282
- Description: The Namibian Education Act (Namibia. Education Act No. 16 of 2001) mandates state secondary school learners to be included in school leadership through a body of learners known as the Learner Representative Council (LRC). The few studies carried out on the LRC in schools reveal that very little has been achieved in terms of learner leadership development. This study explored and provided insight into possible reasons for this, and recommendations. The research questions driving the study were: How is learner leadership currently understood and practised in the school? What are the enabling and constraining factors in the school as far as learner leadership development is concerned? And what can be done to promote learner leadership development? This study is an interpretive case study of learner leadership in the LRC in a Namibian state secondary school in the Oshana region. The conceptual framework used was distributed leadership. The Cultural Historical Activity Theory (CHAT) was used as an analytical tool. The research participants were the LRC members, school principal, Heads of Departments representing the school management members, the School Board Chairperson representing parents and the LRC liaison teacher and were all purposively selected. Data was collected through document analysis, open-ended questionnaires, interviews and non-participant observation. Data analysis took the form of inductively – identifying themes emerged from the data and deductively – using CHAT to surface the systemic contradictions within the learners’ activity system. The data revealed that learner leadership was mostly understood from a management perspective and equated with the formal authority of the LRC in the school. The data further revealed that the LRC performed more leadership roles stretched from inside the classroom, outside the classroom, on the School Board and outside the school. To capture this complexity, I developed a model which may prove useful for future studies of learner leadership. The data also indicated that much support was offered to the LRC members in the school; for example, support from the LRC liaison teacher, the School Management Team and generally from the school, through LRC leadership training. Using CHAT, the findings revealed that the historical context and cultural conventions contradicted the LRC leadership development in the school. In line with a distributed leadership theory, the study recommends that learner leadership should not be limited by position and authority but should be exercised by all learners, through the development and establishment of learner leader clubs in the school. The study also recommends that schools should embark on change initiatives which challenge their traditionally held beliefs and attitudes.
- Full Text:
- Date Issued: 2018
- Authors: Da Silva, Rolens
- Date: 2018
- Subjects: Student participation in administration Namibia , Student government Namibia , Educational leadership Namibia , Qualitative research
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62808 , vital:28282
- Description: The Namibian Education Act (Namibia. Education Act No. 16 of 2001) mandates state secondary school learners to be included in school leadership through a body of learners known as the Learner Representative Council (LRC). The few studies carried out on the LRC in schools reveal that very little has been achieved in terms of learner leadership development. This study explored and provided insight into possible reasons for this, and recommendations. The research questions driving the study were: How is learner leadership currently understood and practised in the school? What are the enabling and constraining factors in the school as far as learner leadership development is concerned? And what can be done to promote learner leadership development? This study is an interpretive case study of learner leadership in the LRC in a Namibian state secondary school in the Oshana region. The conceptual framework used was distributed leadership. The Cultural Historical Activity Theory (CHAT) was used as an analytical tool. The research participants were the LRC members, school principal, Heads of Departments representing the school management members, the School Board Chairperson representing parents and the LRC liaison teacher and were all purposively selected. Data was collected through document analysis, open-ended questionnaires, interviews and non-participant observation. Data analysis took the form of inductively – identifying themes emerged from the data and deductively – using CHAT to surface the systemic contradictions within the learners’ activity system. The data revealed that learner leadership was mostly understood from a management perspective and equated with the formal authority of the LRC in the school. The data further revealed that the LRC performed more leadership roles stretched from inside the classroom, outside the classroom, on the School Board and outside the school. To capture this complexity, I developed a model which may prove useful for future studies of learner leadership. The data also indicated that much support was offered to the LRC members in the school; for example, support from the LRC liaison teacher, the School Management Team and generally from the school, through LRC leadership training. Using CHAT, the findings revealed that the historical context and cultural conventions contradicted the LRC leadership development in the school. In line with a distributed leadership theory, the study recommends that learner leadership should not be limited by position and authority but should be exercised by all learners, through the development and establishment of learner leader clubs in the school. The study also recommends that schools should embark on change initiatives which challenge their traditionally held beliefs and attitudes.
- Full Text:
- Date Issued: 2018
Understanding the experiences of Zimbabwean students as foreign students at South African universities: the case of Rhodes University
- Authors: Daki, Andile Lebohang
- Date: 2019
- Subjects: Rhodes University -- Students -- Attitudes , Zimbabwean college students -- South Africa , Zimbabwean college students -- South Africa -- Conduct of life , Zimbabwean college students -- South Africa -- Psychology
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/96225 , vital:31252
- Description: This thesis seeks to understand the cultural and social experiences of black Zimbabwean students, as foreign students, at Rhodes University in Grahamstown, South Africa. It examines the ways in which black Zimbabwean students negotiate the cultural, social and institutional milieu of Rhodes University, which is a former white English-medium university. In doing so, the thesis draws upon Interface theory because, once entering the university space, these students interpret the space and simultaneously negotiate their way in and through this space along cultural and social interfaces. The fieldwork for the thesis involved in-depth interviews with eighteen black Zimbabwean students at the university, stratified in terms of both gender and year of study. A focus on gender facilitated an understanding of possible differences between male and female Zimbabwean students in terms of social and cultural experiences; while a consideration of year of study allowed for an examination of possible shifts in negotiation over time, from first year to Master’s level. The findings demonstrate a range of challenges faced by black Zimbabwean students while at Rhodes University, some of which arise from differences between Zimbabwean and South African society. At the same time, there are considerable differences amongst black Zimbabwean students in relation to the manner in which negotiation took place. While some students negotiate the space through active socialising and assimilating into the local world and lives of South African students as well as the university’s institutional culture, other students negotiate the space through isolation and alienation. Overall, with regard to adjusting to the world of Rhodes and South Africa, students pursued different routes which, in the end, made sense to them.
- Full Text:
- Date Issued: 2019
- Authors: Daki, Andile Lebohang
- Date: 2019
- Subjects: Rhodes University -- Students -- Attitudes , Zimbabwean college students -- South Africa , Zimbabwean college students -- South Africa -- Conduct of life , Zimbabwean college students -- South Africa -- Psychology
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/96225 , vital:31252
- Description: This thesis seeks to understand the cultural and social experiences of black Zimbabwean students, as foreign students, at Rhodes University in Grahamstown, South Africa. It examines the ways in which black Zimbabwean students negotiate the cultural, social and institutional milieu of Rhodes University, which is a former white English-medium university. In doing so, the thesis draws upon Interface theory because, once entering the university space, these students interpret the space and simultaneously negotiate their way in and through this space along cultural and social interfaces. The fieldwork for the thesis involved in-depth interviews with eighteen black Zimbabwean students at the university, stratified in terms of both gender and year of study. A focus on gender facilitated an understanding of possible differences between male and female Zimbabwean students in terms of social and cultural experiences; while a consideration of year of study allowed for an examination of possible shifts in negotiation over time, from first year to Master’s level. The findings demonstrate a range of challenges faced by black Zimbabwean students while at Rhodes University, some of which arise from differences between Zimbabwean and South African society. At the same time, there are considerable differences amongst black Zimbabwean students in relation to the manner in which negotiation took place. While some students negotiate the space through active socialising and assimilating into the local world and lives of South African students as well as the university’s institutional culture, other students negotiate the space through isolation and alienation. Overall, with regard to adjusting to the world of Rhodes and South Africa, students pursued different routes which, in the end, made sense to them.
- Full Text:
- Date Issued: 2019
Witches & villains: the nasty tales
- Authors: Dalldorf, Tamaryn
- Date: 2018
- Subjects: South African fiction (English) -- 21st century , Short stories, South African (English) -- 21st century , Fairy tales -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63087 , vital:28362
- Description: My thesis compromises a variety of short stories which are modern re-writes of dark fairy tales. Fairy Tales often explore the dark side of human nature and in these stories I focus on the voices of female villains and the strange psychology which drives them. I find Fairy Tales absorbing because they reveal the vulnerabilities, dreams and fears of the human consciousness. My stories contain some satirical expositions of human nature and society. My influences are the anthology of short stories, “My mother She Killed Me and My Father He Ate Me”, The Grimm Fairy Tales (original) and The Fairy Tales of Charles Perrault as well as the writing of Horacio Moya, Angela Carter and Alissa Nutting for their dark satire and mockery of social eccentricities. Kate Bernheimer’s “Form is Fairy Tale and Fairy Tale is Form” is very influential in terms of the style it recommends in writing such as: “every day magic”, “flatness” (a form of narration), abstraction and intuitive logic.
- Full Text:
- Date Issued: 2018
- Authors: Dalldorf, Tamaryn
- Date: 2018
- Subjects: South African fiction (English) -- 21st century , Short stories, South African (English) -- 21st century , Fairy tales -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63087 , vital:28362
- Description: My thesis compromises a variety of short stories which are modern re-writes of dark fairy tales. Fairy Tales often explore the dark side of human nature and in these stories I focus on the voices of female villains and the strange psychology which drives them. I find Fairy Tales absorbing because they reveal the vulnerabilities, dreams and fears of the human consciousness. My stories contain some satirical expositions of human nature and society. My influences are the anthology of short stories, “My mother She Killed Me and My Father He Ate Me”, The Grimm Fairy Tales (original) and The Fairy Tales of Charles Perrault as well as the writing of Horacio Moya, Angela Carter and Alissa Nutting for their dark satire and mockery of social eccentricities. Kate Bernheimer’s “Form is Fairy Tale and Fairy Tale is Form” is very influential in terms of the style it recommends in writing such as: “every day magic”, “flatness” (a form of narration), abstraction and intuitive logic.
- Full Text:
- Date Issued: 2018
Factors influencing estuarine and coastal connectivity of an estuarine-dependent fishery species, Pomadasys commersonnii (Haemulidae)
- Authors: Dames, Michael Henri
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62307 , vital:28153
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
- Authors: Dames, Michael Henri
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62307 , vital:28153
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
The effect of habitat and spatial management on reef fish in an established marine protected area
- Authors: Dames, Vivienne Abigail
- Date: 2021
- Subjects: iSimangaliso Wetland Park (South Africa) -- Management , Reef fishes -- South Africa -- KwaZulu-Natal , Baited remote underwater stereo-video systems (stereo-BRUVs) , Marine parks and reserves -- Monitoring -- South Africa -- KwaZulu-Natal , Fish populations -- Measurement
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171150 , vital:42024
- Description: The persistence of harvested fish populations in the Anthropocene will be determined, above all, by how they respond to the interacting effects of climate change and fisheries exploitation. Predicting how populations will respond to both these threats is essential for any adaptive and sustainable management strategy. The response of fish populations to climate change is underpinned by physiological rates and tolerances, and emerging evidence suggests there may be physiological-based selection in capture fisheries. By quantifying important physiological rates of a model species, the endemic seabream, Chrysoblephus laticeps, across ecologically relevant thermal gradients and from populations subjected to varying intensities of commercial exploitation, this thesis aimed to 1) provide the first physiologically grounded climate resilience assessment for a South African linefish species, and 2) elucidate whether exploitation can drive populations to less physiologically resilient states in response to climate change. To identify physiologically limiting sea temperatures and to determine if exploitation alters physiological trait distributions, an intermittent flow respirometry experiment was used to test the metabolic response of spatially protected and exploited populations of C. laticeps to acute thermal variability. Exploited populations showed reduced metabolic phenotype diversity, fewer high-performance aerobic scope phenotypes, and a significantly lower aerobic scope curve across all test temperatures. Although both populations maintained a relatively high aerobic scope across a wide thermal range, their metabolic rates were compromised when extreme cold events were simulated (8 °C), suggesting that predicted future increases in upwelling frequency and intensity may be the primary limiting factor in a more thermally variable future ocean. The increment widths of annuli in the otoliths of C. laticeps from contemporary and historic collections were measured, as a proxy for the annual growth rate of exploited and protected populations. Hierarchical mixed models were used to partition growth variation within and among individuals and ascribe growth to intrinsic and extrinsic effects. The best model for the protected population indicated that the growth response of C. laticeps was poorer during years characterised by a high cumulative upwelling intensity, and better during years characterised by higher mean autumn sea surface temperatures. The exploited population growth chronology was too short to identify an extrinsic growth driver. The growth results again highlight the role of thermal variability in modulating the response of C. laticeps to its ambient environment and indicate that the predicted increases in upwelling frequency and intensity may constrain future growth rates of this species. A metabolic index (ϕ), representing the ratio of O2 supply to demand at various temperatures and oxygen concentrations, was estimated for exploited and protected populations of C. laticeps and used to predict future distribution responses. There was no difference in the laboratory calibrations of ϕ between populations, and all data was subsequently combined into a single piecewise (12 °C) calibrated ϕ model. To predict the distribution of C. laticeps, ϕ was projected across a high-resolution ocean model of the South African coastal zone, and a species distribution model implemented using the random forest algorithm and C. laticeps occurrence points. The future distribution of C. laticeps was estimated by predicting trained models across ocean model projections up to 2100. The best predictor of C. laticeps’ current distribution was minimum monthly ϕ and future predictions indicated only a slight range contraction on either edge of C. laticeps’ distribution by 2100. In order to provide policy makers, currently developing climate change management frameworks for South Africa’s ocean, with a usable output, the results of all research chapters were combined into a marine spatial model. The spatial model identified areas where C. laticeps is predicted to be resilient to climate change in terms of physiology, growth and distribution responses, which can then be prioritised for adaptation measures, such as spatial protection from exploitation. While these results are specific to C. laticeps, the methodology developed to identify areas of climate resilience has broad applications across taxa. From a global perspective, perhaps the most salient points to consider from this case study are the evidence of selective exploitation on physiological traits and the importance of environmental variability, rather than long-term mean climate changes, in affecting organism performance. These ideas are congruent with the current paradigm shift in how we think of the ocean, selective fisheries, and how they relate to organism climate resilience.
- Full Text:
- Date Issued: 2021
- Authors: Dames, Vivienne Abigail
- Date: 2021
- Subjects: iSimangaliso Wetland Park (South Africa) -- Management , Reef fishes -- South Africa -- KwaZulu-Natal , Baited remote underwater stereo-video systems (stereo-BRUVs) , Marine parks and reserves -- Monitoring -- South Africa -- KwaZulu-Natal , Fish populations -- Measurement
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171150 , vital:42024
- Description: The persistence of harvested fish populations in the Anthropocene will be determined, above all, by how they respond to the interacting effects of climate change and fisheries exploitation. Predicting how populations will respond to both these threats is essential for any adaptive and sustainable management strategy. The response of fish populations to climate change is underpinned by physiological rates and tolerances, and emerging evidence suggests there may be physiological-based selection in capture fisheries. By quantifying important physiological rates of a model species, the endemic seabream, Chrysoblephus laticeps, across ecologically relevant thermal gradients and from populations subjected to varying intensities of commercial exploitation, this thesis aimed to 1) provide the first physiologically grounded climate resilience assessment for a South African linefish species, and 2) elucidate whether exploitation can drive populations to less physiologically resilient states in response to climate change. To identify physiologically limiting sea temperatures and to determine if exploitation alters physiological trait distributions, an intermittent flow respirometry experiment was used to test the metabolic response of spatially protected and exploited populations of C. laticeps to acute thermal variability. Exploited populations showed reduced metabolic phenotype diversity, fewer high-performance aerobic scope phenotypes, and a significantly lower aerobic scope curve across all test temperatures. Although both populations maintained a relatively high aerobic scope across a wide thermal range, their metabolic rates were compromised when extreme cold events were simulated (8 °C), suggesting that predicted future increases in upwelling frequency and intensity may be the primary limiting factor in a more thermally variable future ocean. The increment widths of annuli in the otoliths of C. laticeps from contemporary and historic collections were measured, as a proxy for the annual growth rate of exploited and protected populations. Hierarchical mixed models were used to partition growth variation within and among individuals and ascribe growth to intrinsic and extrinsic effects. The best model for the protected population indicated that the growth response of C. laticeps was poorer during years characterised by a high cumulative upwelling intensity, and better during years characterised by higher mean autumn sea surface temperatures. The exploited population growth chronology was too short to identify an extrinsic growth driver. The growth results again highlight the role of thermal variability in modulating the response of C. laticeps to its ambient environment and indicate that the predicted increases in upwelling frequency and intensity may constrain future growth rates of this species. A metabolic index (ϕ), representing the ratio of O2 supply to demand at various temperatures and oxygen concentrations, was estimated for exploited and protected populations of C. laticeps and used to predict future distribution responses. There was no difference in the laboratory calibrations of ϕ between populations, and all data was subsequently combined into a single piecewise (12 °C) calibrated ϕ model. To predict the distribution of C. laticeps, ϕ was projected across a high-resolution ocean model of the South African coastal zone, and a species distribution model implemented using the random forest algorithm and C. laticeps occurrence points. The future distribution of C. laticeps was estimated by predicting trained models across ocean model projections up to 2100. The best predictor of C. laticeps’ current distribution was minimum monthly ϕ and future predictions indicated only a slight range contraction on either edge of C. laticeps’ distribution by 2100. In order to provide policy makers, currently developing climate change management frameworks for South Africa’s ocean, with a usable output, the results of all research chapters were combined into a marine spatial model. The spatial model identified areas where C. laticeps is predicted to be resilient to climate change in terms of physiology, growth and distribution responses, which can then be prioritised for adaptation measures, such as spatial protection from exploitation. While these results are specific to C. laticeps, the methodology developed to identify areas of climate resilience has broad applications across taxa. From a global perspective, perhaps the most salient points to consider from this case study are the evidence of selective exploitation on physiological traits and the importance of environmental variability, rather than long-term mean climate changes, in affecting organism performance. These ideas are congruent with the current paradigm shift in how we think of the ocean, selective fisheries, and how they relate to organism climate resilience.
- Full Text:
- Date Issued: 2021
Water footprint and economic water productivity of citrus production: a comparison across three river valleys in the Eastern Cape Milands
- Authors: Danckwerts, Lindsay
- Date: 2020
- Subjects: Water in agriculture -- South Africa -- Eastern Cape , Water consumption -- South Africa -- Economic aspects , Water supply, Agricultural -- South Africa -- Eastern Cape , Citrus fruit industry -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/141064 , vital:37941
- Description: South Africa is a semi-arid, water scarce country. The nation has suffered a spate of severe droughts in several regions in recent years, which have significantly impacted the country’s economy. Global warming, population growth, and rising demand for water intensive products are only expected to intensify water supply problems in the future. The agricultural industry is the largest consumer of water in South Africa, accounting for the majority of total surface water withdrawals. As such, the agricultural sector is faced with complex and difficult management decisions in the face of a potential water supply crisis. The water footprint (WF) and economic water productivity (EWP) of citrus production across three river catchments located in the Eastern Cape Midlands (situated in the vicinity of the settlements of Adelaide, Cookhouse and Fort Beaufort respectively) were calculated and compared. In the long-term average (LTA), blue WF weighted across all three regions accounted for the greatest proportion of total WF (53%), followed in turn by green and grey WF (30% and 17% respectively). LTA blue and grey WF was lowest in the Adelaide region, while green WF was smallest in the Fort Beaufort region. Blue, green and grey WF were found to be greatest in the Cookhouse region. LTA EWP was greatest in the Fort Beaufort region and smallest in the Adelaide region. Of all variety groups assessed, lemons were found to have the lowest LTA crop water use and blue, green and grey WF when considering citrus production averaged across all three study regions. Satsumas has the second smallest LTA blue, green and grey WF, followed by navels, mid-season mandarins, and finally, late mandarins. Lemons had the greatest LTA EWP of all varieties, followed in turn by satsumas, late mandarins, mid-season mandarins and navels. Blue crop water use was consistently lowest in the designated wet year and highest in the dry year. However, this same trend was not necessarily true for WF findings. WF and EWP are useful indicators of water use which can be used to help guide complex water management decisions. However, these indicators are single-factor productivity measures applied in a multi-factor environment. It is therefore important that factors outside of water use are considered when making water management decisions. Moreover, it is important to examine the impact that the various components making up WF and EWP have on the resultant figures, rather than merely considering the superficial results themselves. Factors such as CWU, orchard maturity, crop choice, potential yield, climate, irrigation system, economic return, water allocation and water availability should all be taken into account.
- Full Text:
- Date Issued: 2020
- Authors: Danckwerts, Lindsay
- Date: 2020
- Subjects: Water in agriculture -- South Africa -- Eastern Cape , Water consumption -- South Africa -- Economic aspects , Water supply, Agricultural -- South Africa -- Eastern Cape , Citrus fruit industry -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/141064 , vital:37941
- Description: South Africa is a semi-arid, water scarce country. The nation has suffered a spate of severe droughts in several regions in recent years, which have significantly impacted the country’s economy. Global warming, population growth, and rising demand for water intensive products are only expected to intensify water supply problems in the future. The agricultural industry is the largest consumer of water in South Africa, accounting for the majority of total surface water withdrawals. As such, the agricultural sector is faced with complex and difficult management decisions in the face of a potential water supply crisis. The water footprint (WF) and economic water productivity (EWP) of citrus production across three river catchments located in the Eastern Cape Midlands (situated in the vicinity of the settlements of Adelaide, Cookhouse and Fort Beaufort respectively) were calculated and compared. In the long-term average (LTA), blue WF weighted across all three regions accounted for the greatest proportion of total WF (53%), followed in turn by green and grey WF (30% and 17% respectively). LTA blue and grey WF was lowest in the Adelaide region, while green WF was smallest in the Fort Beaufort region. Blue, green and grey WF were found to be greatest in the Cookhouse region. LTA EWP was greatest in the Fort Beaufort region and smallest in the Adelaide region. Of all variety groups assessed, lemons were found to have the lowest LTA crop water use and blue, green and grey WF when considering citrus production averaged across all three study regions. Satsumas has the second smallest LTA blue, green and grey WF, followed by navels, mid-season mandarins, and finally, late mandarins. Lemons had the greatest LTA EWP of all varieties, followed in turn by satsumas, late mandarins, mid-season mandarins and navels. Blue crop water use was consistently lowest in the designated wet year and highest in the dry year. However, this same trend was not necessarily true for WF findings. WF and EWP are useful indicators of water use which can be used to help guide complex water management decisions. However, these indicators are single-factor productivity measures applied in a multi-factor environment. It is therefore important that factors outside of water use are considered when making water management decisions. Moreover, it is important to examine the impact that the various components making up WF and EWP have on the resultant figures, rather than merely considering the superficial results themselves. Factors such as CWU, orchard maturity, crop choice, potential yield, climate, irrigation system, economic return, water allocation and water availability should all be taken into account.
- Full Text:
- Date Issued: 2020
Improving the cold tolerance of false codling moth, thaumatotibia leucotreta, for better performance in a sterile insect release programme
- Authors: Daniel, Claire Ashleigh
- Date: 2017
- Subjects: Cryptophlebia leucotreta -- South Africa , Cryptophlebia leucotreta -- Reproduction -- Effect of temperature on , Cryptophlebia leucotreta -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Insect pests -- Biological control -- South Africa , Insecticides , Citrus fruit industry -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/5271 , vital:20803
- Description: The false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a major pest of citrus and other important crops in Sub-Saharan Africa. The introduction of a sterile insect technique (SIT) programme for FCM in South Africa has proven to be very effective in the control of FCM. The objective was to flood citrus orchards with large numbers of sterile males resulting in a ratio of at least 10 sterile to 1 wild moth, increasing the probability of a female moth mating with a sterile male. This target is often achieved and the programme is generally successful, however there are some challenges regarding this programme. The mass rearing environment, artificial diet, handling methods and irradiation have an impact on sterile insect quality as environmental differences between the rearing facility and field, influences the insect phenotype and competitiveness. This is evident as wild male moths can theoretically actively fly at a temperature of 12°C and laboratory-reared sterilized moths, due to the radiation treatment, appear unable to fly below 20°C. As a consequence, sterile males are out-competed by wild males during the cooler months of the year. This is detrimental to the SIT programme as FCM do not undergo diapause, meaning they are active during winter and will still reproduce. Therefore, to maximize the effect of the SIT programme, it is vital to increase the flight ability of mass reared sterile males at lower temperatures. Various studies have shown that by adding cryoprotectants to the basic laboratory diets increases the cold tolerance of certain insects and thus may allow them to be mobile at lower temperatures, however it imperative that any chemical used to augment the commercial diet of the insect has no negative effects on the insect physiology and development. To investigate this detail for FCM, five generations of FCM were reared on diets augmented with various known insect cryoprotectants. These augmented FCM were subsequently used in experiments designed to determine firstly, if the cryoprotectants had a positive result on the cold tolerance of the FCM, and secondly, if they had any adverse effects on other physiological aspects such as duration of development. Laboratory trials indicated that the flight ability of male FCM was improved when larvae were reared on diets augmented with trehalose and cholesterol (with an average of 40 % of cholesterol and trehalose augmented males that flew at 15 °C where 0 % of the control flew). Results obtained during the field trials support the laboratory results as there was a significant increase in the number of trehalose augmented moths caught in the field during March and July (winter). Results also showed potential for cholesterol to be used as an additive. Other important findings show that both cholesterol and trehalose have no negative impacts on developmental rate, pupal size, and egg production and viability. Trehalose was found to increase the pupal mass of male and female FCM, as well as the number of eggs laid per female. Cholesterol was found to increase developmental rate and the number of eggs laid. The main findings of this study were that diet additives could improve the massrearing of FCM for SIT and the competitiveness of the males, especially at lower temperatures. However, the additives were expensive and cost could well be a constraint to the wide scale implementation of the new technology.
- Full Text:
- Date Issued: 2017
- Authors: Daniel, Claire Ashleigh
- Date: 2017
- Subjects: Cryptophlebia leucotreta -- South Africa , Cryptophlebia leucotreta -- Reproduction -- Effect of temperature on , Cryptophlebia leucotreta -- Biological control -- South Africa , Citrus -- Diseases and pests -- Biological control -- South Africa , Insect pests -- Biological control -- South Africa , Insecticides , Citrus fruit industry -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/5271 , vital:20803
- Description: The false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a major pest of citrus and other important crops in Sub-Saharan Africa. The introduction of a sterile insect technique (SIT) programme for FCM in South Africa has proven to be very effective in the control of FCM. The objective was to flood citrus orchards with large numbers of sterile males resulting in a ratio of at least 10 sterile to 1 wild moth, increasing the probability of a female moth mating with a sterile male. This target is often achieved and the programme is generally successful, however there are some challenges regarding this programme. The mass rearing environment, artificial diet, handling methods and irradiation have an impact on sterile insect quality as environmental differences between the rearing facility and field, influences the insect phenotype and competitiveness. This is evident as wild male moths can theoretically actively fly at a temperature of 12°C and laboratory-reared sterilized moths, due to the radiation treatment, appear unable to fly below 20°C. As a consequence, sterile males are out-competed by wild males during the cooler months of the year. This is detrimental to the SIT programme as FCM do not undergo diapause, meaning they are active during winter and will still reproduce. Therefore, to maximize the effect of the SIT programme, it is vital to increase the flight ability of mass reared sterile males at lower temperatures. Various studies have shown that by adding cryoprotectants to the basic laboratory diets increases the cold tolerance of certain insects and thus may allow them to be mobile at lower temperatures, however it imperative that any chemical used to augment the commercial diet of the insect has no negative effects on the insect physiology and development. To investigate this detail for FCM, five generations of FCM were reared on diets augmented with various known insect cryoprotectants. These augmented FCM were subsequently used in experiments designed to determine firstly, if the cryoprotectants had a positive result on the cold tolerance of the FCM, and secondly, if they had any adverse effects on other physiological aspects such as duration of development. Laboratory trials indicated that the flight ability of male FCM was improved when larvae were reared on diets augmented with trehalose and cholesterol (with an average of 40 % of cholesterol and trehalose augmented males that flew at 15 °C where 0 % of the control flew). Results obtained during the field trials support the laboratory results as there was a significant increase in the number of trehalose augmented moths caught in the field during March and July (winter). Results also showed potential for cholesterol to be used as an additive. Other important findings show that both cholesterol and trehalose have no negative impacts on developmental rate, pupal size, and egg production and viability. Trehalose was found to increase the pupal mass of male and female FCM, as well as the number of eggs laid per female. Cholesterol was found to increase developmental rate and the number of eggs laid. The main findings of this study were that diet additives could improve the massrearing of FCM for SIT and the competitiveness of the males, especially at lower temperatures. However, the additives were expensive and cost could well be a constraint to the wide scale implementation of the new technology.
- Full Text:
- Date Issued: 2017
"Making the News": a case study of East Cape News (ECN)
- Authors: Davidow, Audrey Beth
- Date: 1999
- Subjects: Reporters and reporting Reporters and reporting -- South Africa Attribution of news News agencies -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3424 , http://hdl.handle.net/10962/d1002877
- Description: To fully comprehend the complex process of news making, we must first understand that the events we read about everyday in the newspaper are not merely a reflection of the world in which we live. News does not just happen. Rather, it is a socially constructed product in which events are “made to mean” (Hall, 1978). Thus, the news plays a fundamental role in shaping our interpretations of reality - our perceptions of the world as we know it. Informed by a structuralist approach to news making, this research provides a detailed ethnographic study of the determinants that shape and produce news in the South African print media. I provide examples of the influence various factors, operating at all levels, exert within the news making process. The research focuses on the news production process at East Cape News Pty. Ltd. (ECN) a small news agency operating in the peripheral news region of South Africa’s Eastern Cape. It considers the journalistic routines and interests of the ECN reporters; how these reporters select events and turn them into news, how they interpret their significance and how they formulate them as news stories. The research also considers the second stage of selection ECN news must pass before it is read by the public - the “gates” of external newspapers. In this section, the study is primarily concerned with which ECN news stories succeed past the gates of national newspapers as these are the newpapers that play an influential role in shaping national perceptions of the marginalised Eastern Cape region. A province burdened with devastating rural poverty, unstable government, and little economic growth, the Eastern Cape warrants little coverage from the national, Johannesburg-based news market. As a result, little news of the Eastern Cape is published nationally, further perpetuating the region’s perceived insignificance on a national level. This point also demonstrates the fact that news both shapes, and is shaped by, our ideologies. News, therefore is ideological (Fishman, 1977). My findings reinforce many of the observations of other media researchers informed by a structuralist approach in the field of news making. However, some elements of news making emerge which appear to be unique in terms of other studies of news making. These elements are primarily a result of ECN’s informal organisational structures which allow the journalists a greater level of autonomy than a larger more bureaucratic organisation might. Thus, in addition to considering the structures that shape the news, I also discuss the role of human agency in making the news.
- Full Text:
- Date Issued: 1999
- Authors: Davidow, Audrey Beth
- Date: 1999
- Subjects: Reporters and reporting Reporters and reporting -- South Africa Attribution of news News agencies -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3424 , http://hdl.handle.net/10962/d1002877
- Description: To fully comprehend the complex process of news making, we must first understand that the events we read about everyday in the newspaper are not merely a reflection of the world in which we live. News does not just happen. Rather, it is a socially constructed product in which events are “made to mean” (Hall, 1978). Thus, the news plays a fundamental role in shaping our interpretations of reality - our perceptions of the world as we know it. Informed by a structuralist approach to news making, this research provides a detailed ethnographic study of the determinants that shape and produce news in the South African print media. I provide examples of the influence various factors, operating at all levels, exert within the news making process. The research focuses on the news production process at East Cape News Pty. Ltd. (ECN) a small news agency operating in the peripheral news region of South Africa’s Eastern Cape. It considers the journalistic routines and interests of the ECN reporters; how these reporters select events and turn them into news, how they interpret their significance and how they formulate them as news stories. The research also considers the second stage of selection ECN news must pass before it is read by the public - the “gates” of external newspapers. In this section, the study is primarily concerned with which ECN news stories succeed past the gates of national newspapers as these are the newpapers that play an influential role in shaping national perceptions of the marginalised Eastern Cape region. A province burdened with devastating rural poverty, unstable government, and little economic growth, the Eastern Cape warrants little coverage from the national, Johannesburg-based news market. As a result, little news of the Eastern Cape is published nationally, further perpetuating the region’s perceived insignificance on a national level. This point also demonstrates the fact that news both shapes, and is shaped by, our ideologies. News, therefore is ideological (Fishman, 1977). My findings reinforce many of the observations of other media researchers informed by a structuralist approach in the field of news making. However, some elements of news making emerge which appear to be unique in terms of other studies of news making. These elements are primarily a result of ECN’s informal organisational structures which allow the journalists a greater level of autonomy than a larger more bureaucratic organisation might. Thus, in addition to considering the structures that shape the news, I also discuss the role of human agency in making the news.
- Full Text:
- Date Issued: 1999
Categorising Network Telescope data using big data enrichment techniques
- Authors: Davis, Michael Reginald
- Date: 2019
- Subjects: Denial of service attacks , Big data , Computer networks -- Security measures
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92941 , vital:30766
- Description: Network Telescopes, Internet backbone sampling, IDS and other forms of network-sourced Threat Intelligence provide researchers with insight into the methods and intent of remote entities by capturing network traffic and analysing the resulting data. This analysis and determination of intent is made difficult by the large amounts of potentially malicious traffic, coupled with limited amount of knowledge that can be attributed to the source of the incoming data, as the source is known only by its IP address. Due to the lack of commonly available tooling, many researchers start this analysis from the beginning and so repeat and re-iterate previous research as the bulk of their work. As a result new insight into methods and approaches of analysis is gained at a high cost. Our research approaches this problem by using additional knowledge about the source IP address such as open ports, reverse and forward DNS, BGP routing tables and more, to enhance the researcher's ability to understand the traffic source. The research is a BigData experiment, where large (hundreds of GB) datasets are merged with a two month section of Network Telescope data using a set of Python scripts. The result are written to a Google BigQuery database table. Analysis of the network data is greatly simplified, with questions about the nature of the source, such as its device class (home routing device or server), potential vulnerabilities (open telnet ports or databases) and location becoming relatively easy to answer. Using this approach, researchers can focus on the questions that need answering and efficiently address them. This research could be taken further by using additional data sources such as Geo-location, WHOIS lookups, Threat Intelligence feeds and many others. Other potential areas of research include real-time categorisation of incoming packets, in order to better inform alerting and reporting systems' configuration. In conclusion, categorising Network Telescope data in this way provides insight into the intent of the (apparent) originator and as such is a valuable tool for those seeking to understand the purpose and intent of arriving packets. In particular, the ability to remove packets categorised as non-malicious (e.g. those in the Research category) from the data eliminates a known source of `noise' from the data. This allows the researcher to focus their efforts in a more productive manner.
- Full Text:
- Date Issued: 2019
- Authors: Davis, Michael Reginald
- Date: 2019
- Subjects: Denial of service attacks , Big data , Computer networks -- Security measures
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92941 , vital:30766
- Description: Network Telescopes, Internet backbone sampling, IDS and other forms of network-sourced Threat Intelligence provide researchers with insight into the methods and intent of remote entities by capturing network traffic and analysing the resulting data. This analysis and determination of intent is made difficult by the large amounts of potentially malicious traffic, coupled with limited amount of knowledge that can be attributed to the source of the incoming data, as the source is known only by its IP address. Due to the lack of commonly available tooling, many researchers start this analysis from the beginning and so repeat and re-iterate previous research as the bulk of their work. As a result new insight into methods and approaches of analysis is gained at a high cost. Our research approaches this problem by using additional knowledge about the source IP address such as open ports, reverse and forward DNS, BGP routing tables and more, to enhance the researcher's ability to understand the traffic source. The research is a BigData experiment, where large (hundreds of GB) datasets are merged with a two month section of Network Telescope data using a set of Python scripts. The result are written to a Google BigQuery database table. Analysis of the network data is greatly simplified, with questions about the nature of the source, such as its device class (home routing device or server), potential vulnerabilities (open telnet ports or databases) and location becoming relatively easy to answer. Using this approach, researchers can focus on the questions that need answering and efficiently address them. This research could be taken further by using additional data sources such as Geo-location, WHOIS lookups, Threat Intelligence feeds and many others. Other potential areas of research include real-time categorisation of incoming packets, in order to better inform alerting and reporting systems' configuration. In conclusion, categorising Network Telescope data in this way provides insight into the intent of the (apparent) originator and as such is a valuable tool for those seeking to understand the purpose and intent of arriving packets. In particular, the ability to remove packets categorised as non-malicious (e.g. those in the Research category) from the data eliminates a known source of `noise' from the data. This allows the researcher to focus their efforts in a more productive manner.
- Full Text:
- Date Issued: 2019
An exploratory study of psychologists’ perceptions of the phenomenon currently understood as ‘borderline personality disorder’
- Authors: Daya, Lekha
- Date: 2021
- Subjects: Borderline personality disorder , Psychologists -- Attitudes -- South Africa , Diagnostic and statistical manual of mental disorders
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/171139 , vital:42023
- Description: The phenomenon currently understood as ‘borderline personality disorder’ (BPD) has been complex and multifaceted since its inception. Previous studies have focused on the validity of The Diagnostic and Statistical Manual of Mental Disorders (DSM) conceptualisation of BPD, aetiologies of BPD, the psychologies of persons diagnosed with BPD, and the gendered nature of BPD. This study aimed to specifically explore South African practising psychologists’ perceptions of BPD. Through thematic analysis from a constructivist, post-modern paradigm, this study aimed to explore the perceptions and experiences of practising psychologists on BPD, as well as the usefulness of the DSM in working with BPD in a non-western society such as South Africa (SA). The study sampled two Counselling and two Clinical psychologists practising in the South African context, with exposure to and experience in working with BPD. Collectively, results in this study identified psychologists’ perceptions of shortcomings in the usefulness of the DSM’s approach to categorising phenomena associated with BPD, and brought attention to a need for further research and attention into the role of psychologists’ in the construction of BPD. This study seeks to represent psychologists’ practical experiences and perceptions, in an attempt to add contextually relevant findings on the DSM’s construction of BPD, and to contribute to challenging the stigma and misunderstanding associated with BPD. Specific practice implications and recommendations for future research are discussed within.
- Full Text:
- Date Issued: 2021
- Authors: Daya, Lekha
- Date: 2021
- Subjects: Borderline personality disorder , Psychologists -- Attitudes -- South Africa , Diagnostic and statistical manual of mental disorders
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/171139 , vital:42023
- Description: The phenomenon currently understood as ‘borderline personality disorder’ (BPD) has been complex and multifaceted since its inception. Previous studies have focused on the validity of The Diagnostic and Statistical Manual of Mental Disorders (DSM) conceptualisation of BPD, aetiologies of BPD, the psychologies of persons diagnosed with BPD, and the gendered nature of BPD. This study aimed to specifically explore South African practising psychologists’ perceptions of BPD. Through thematic analysis from a constructivist, post-modern paradigm, this study aimed to explore the perceptions and experiences of practising psychologists on BPD, as well as the usefulness of the DSM in working with BPD in a non-western society such as South Africa (SA). The study sampled two Counselling and two Clinical psychologists practising in the South African context, with exposure to and experience in working with BPD. Collectively, results in this study identified psychologists’ perceptions of shortcomings in the usefulness of the DSM’s approach to categorising phenomena associated with BPD, and brought attention to a need for further research and attention into the role of psychologists’ in the construction of BPD. This study seeks to represent psychologists’ practical experiences and perceptions, in an attempt to add contextually relevant findings on the DSM’s construction of BPD, and to contribute to challenging the stigma and misunderstanding associated with BPD. Specific practice implications and recommendations for future research are discussed within.
- Full Text:
- Date Issued: 2021
The effect of age and maturation on anthropometric characteristics and physical abilities of youth South African footballers
- Authors: De Beer, Ashley
- Date: 2020
- Subjects: Soccer -- Physiologial aspects , Soccer players -- South Africa -- Makhanda -- Physiology , Soccer players -- South Africa -- Makhanda -- Psychophysiology , Makana Local Football Association (South Africa)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/141222 , vital:37954
- Description: Currently there is limited research investigating the football related abilities of youth South African individuals. Populations from North and South America, Europe and Asia have been extensively covered in terms of their anthropometric characteristics, physical abilities, technical competency, tactical understanding as well as various personality traits. In describing these details, and especially how each is affected during the ageing and pubertal process, a more informed understanding of the talent development systems is created. A holistic approach to talent development is required to effectively and efficiently produce elite level footballers. An important consideration is the unique socio-economic environment many youth footballers experience which may impact on the talent development process. The present study therefore sought to quantify the anthropometric characteristics and the physical ability level of youth South African footballers from Local Football Association in Makhanda in the Sarah Baartman Region of the Eastern Cape province. In order to achieve this a two-factorial design was used with age and maturity status as independent variables. Anthropometric characteristics were tested by finding the height, weight, body mass index and total fat percentage of participants. Physical ability was determined by results for aerobic capacity, power, acceleration, speed and agility. All tests were football specific and had been widely used in a variety of footballing studies. Additional demographic and socio-economic information was also recorded. A total of 136 participants were placed in their respective Under 11, 13, 15 or Under 19 age groups, while the maturity status of 96 participants were stratified into five distinct categories. Statistical analyses was conducted using p-value significance, with appropriate Tukey post-hoc tests administered when necessary, while effect sizes were calculated using Cohen’s d. Significant changes and practical effect sizes were present for nearly all dependent variables when either stratified by age or by maturity. Total fat percentage was the only dependent variable which was not influenced by either age or maturity. Age and maturity effect sizes for total body fat percentage indicated practical changes present which did not occur during statistical analysis. The present results indicate poor values when compared to normative data or that of other football playing study populations. Further longitudinal research is required to better understand individual growth rates for youth South African footballers, particularly from the Makana region. Implications of the thesis may determine long term development pathways, while the delayed maturity rate is a critical finding which needs to be further researched.
- Full Text:
- Date Issued: 2020
- Authors: De Beer, Ashley
- Date: 2020
- Subjects: Soccer -- Physiologial aspects , Soccer players -- South Africa -- Makhanda -- Physiology , Soccer players -- South Africa -- Makhanda -- Psychophysiology , Makana Local Football Association (South Africa)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/141222 , vital:37954
- Description: Currently there is limited research investigating the football related abilities of youth South African individuals. Populations from North and South America, Europe and Asia have been extensively covered in terms of their anthropometric characteristics, physical abilities, technical competency, tactical understanding as well as various personality traits. In describing these details, and especially how each is affected during the ageing and pubertal process, a more informed understanding of the talent development systems is created. A holistic approach to talent development is required to effectively and efficiently produce elite level footballers. An important consideration is the unique socio-economic environment many youth footballers experience which may impact on the talent development process. The present study therefore sought to quantify the anthropometric characteristics and the physical ability level of youth South African footballers from Local Football Association in Makhanda in the Sarah Baartman Region of the Eastern Cape province. In order to achieve this a two-factorial design was used with age and maturity status as independent variables. Anthropometric characteristics were tested by finding the height, weight, body mass index and total fat percentage of participants. Physical ability was determined by results for aerobic capacity, power, acceleration, speed and agility. All tests were football specific and had been widely used in a variety of footballing studies. Additional demographic and socio-economic information was also recorded. A total of 136 participants were placed in their respective Under 11, 13, 15 or Under 19 age groups, while the maturity status of 96 participants were stratified into five distinct categories. Statistical analyses was conducted using p-value significance, with appropriate Tukey post-hoc tests administered when necessary, while effect sizes were calculated using Cohen’s d. Significant changes and practical effect sizes were present for nearly all dependent variables when either stratified by age or by maturity. Total fat percentage was the only dependent variable which was not influenced by either age or maturity. Age and maturity effect sizes for total body fat percentage indicated practical changes present which did not occur during statistical analysis. The present results indicate poor values when compared to normative data or that of other football playing study populations. Further longitudinal research is required to better understand individual growth rates for youth South African footballers, particularly from the Makana region. Implications of the thesis may determine long term development pathways, while the delayed maturity rate is a critical finding which needs to be further researched.
- Full Text:
- Date Issued: 2020
Oor die kortkuns van John Miles
- Authors: De Beer, Marésa
- Date: 1988
- Subjects: Miles, John, 1938- -- Criticism and interpretation
- Language: Afrikaans
- Type: text , Thesis , Masters , MA
- Identifier: vital:3569 , http://hdl.handle.net/10962/d1002092
- Description: This thesis involves intensive analyses of some of the short-short stories in John Miles's Liefs nie op straat nie, in order to reveal the narrative strategies employed in each. In other words, it is geared to "the rules that govern ... textual actualization and, consequently, those rules that govern the way literary discourse functions as communication" (Riffaterre 1983: 158). Subsequently, attention is given to the interrelationship among the texts, the way in which they act upon one another and interact with the title of the volume, in order to establish the function of such relations. The following texts are analysed in consecutive chapters: "Lucy", "Lappies, kan jy my hoor, Lappies?", "Voorgevoel", "Dom Nakkie, my Dom Nakkie" and "Wie het nog Dom Nakkie gesien?", "Hy staan by die deur en hy klop", "Gustav gaan speel", and "Liefs nie op straat nie". In a concluding chapter the implications of the title are discussed with reference to all the texts in the volume, including those not analysed individually. It is concluded that, on the one hand, the expectations raised by the title are ironicized because the title is never "completed" explicitly, and because that which, by implication, should not be seen in public ("op straat"), is specifically situated in the street and scrutinized in close-up. But on the other hand the title also evokes a peculiar mentality present in all the texts, either in the narrators, or in the characters, or in both. The discussion of "Lucy" is focussed mainly on the contrast and interaction between the world of the child and that of the adult and on the way in which this interaction is actualized within the text through the contrast in the experience of time, the use of "mémoire involontaire", "durée" and the contrasts between (and overlapping of) narrative perspective and focalization. In respect of "Lappies, kan jy my hoor, Lappies?" special attention is paid to similarities and contrasts between this text and the traditional suspense story, notably the way in which conventional techniques are employed to create suspense, as well as to generate an entire subtext which eventually "relocates" the text on the niveau of the murderer's psychological dilemma. In discussing "Voorgevoel" emphasis is not placed primarily on what is conveyed by the narrator, but on the way in which his intentions are subverted both by the window pane through which he is looking and by the narration as such. In this way he is foregrounded and revealed as narrator, just as the text is foregrounded and revealed as literature, with the emphasis, in both cases, not only on their defence mechanisms but also on their impotence. "Dom Nakkie, my Dom Nakkie" and "Wie het nog Dom Nakkie gesien?" are grouped together in one chapter in order to illuminate the interaction between the two narratives in the first text, as well as the interaction between the two texts. Ultimately, they may be seen as three narratives juxtaposed through irony and relativism. The "triumph" of the "preferably not in public" mentality, both in the text and in society, is also illustrated by the interaction between the three narratives. In chapter, 5, in which "Hy staan by die deur en hy klop" is discussed, attention is focussed on the ironic function of the Biblical references, the contrast between Jan and the rest of society, and the way in which the "climax" is located within the Iserian "blank" in the text, so that the entire process of decoding is based on a filling in of that "blank" and its implications. "Gustav gaan speel" is based loosely on Barthes's lexia model, in order to determine the signifying process in the text, and also to demonstrate the way in which the text presupposes rereading. In the discussion of the title text it is revealed how the text is centered in the basic dichotomy between the narrator-as-writer and the journalist, and the way in which this polarity is relativized by the text as such. The text is demonstrated to be the credo of the volume as a whole as well as of the fiction of the Seventies in Afrikaans.
- Full Text:
- Date Issued: 1988
- Authors: De Beer, Marésa
- Date: 1988
- Subjects: Miles, John, 1938- -- Criticism and interpretation
- Language: Afrikaans
- Type: text , Thesis , Masters , MA
- Identifier: vital:3569 , http://hdl.handle.net/10962/d1002092
- Description: This thesis involves intensive analyses of some of the short-short stories in John Miles's Liefs nie op straat nie, in order to reveal the narrative strategies employed in each. In other words, it is geared to "the rules that govern ... textual actualization and, consequently, those rules that govern the way literary discourse functions as communication" (Riffaterre 1983: 158). Subsequently, attention is given to the interrelationship among the texts, the way in which they act upon one another and interact with the title of the volume, in order to establish the function of such relations. The following texts are analysed in consecutive chapters: "Lucy", "Lappies, kan jy my hoor, Lappies?", "Voorgevoel", "Dom Nakkie, my Dom Nakkie" and "Wie het nog Dom Nakkie gesien?", "Hy staan by die deur en hy klop", "Gustav gaan speel", and "Liefs nie op straat nie". In a concluding chapter the implications of the title are discussed with reference to all the texts in the volume, including those not analysed individually. It is concluded that, on the one hand, the expectations raised by the title are ironicized because the title is never "completed" explicitly, and because that which, by implication, should not be seen in public ("op straat"), is specifically situated in the street and scrutinized in close-up. But on the other hand the title also evokes a peculiar mentality present in all the texts, either in the narrators, or in the characters, or in both. The discussion of "Lucy" is focussed mainly on the contrast and interaction between the world of the child and that of the adult and on the way in which this interaction is actualized within the text through the contrast in the experience of time, the use of "mémoire involontaire", "durée" and the contrasts between (and overlapping of) narrative perspective and focalization. In respect of "Lappies, kan jy my hoor, Lappies?" special attention is paid to similarities and contrasts between this text and the traditional suspense story, notably the way in which conventional techniques are employed to create suspense, as well as to generate an entire subtext which eventually "relocates" the text on the niveau of the murderer's psychological dilemma. In discussing "Voorgevoel" emphasis is not placed primarily on what is conveyed by the narrator, but on the way in which his intentions are subverted both by the window pane through which he is looking and by the narration as such. In this way he is foregrounded and revealed as narrator, just as the text is foregrounded and revealed as literature, with the emphasis, in both cases, not only on their defence mechanisms but also on their impotence. "Dom Nakkie, my Dom Nakkie" and "Wie het nog Dom Nakkie gesien?" are grouped together in one chapter in order to illuminate the interaction between the two narratives in the first text, as well as the interaction between the two texts. Ultimately, they may be seen as three narratives juxtaposed through irony and relativism. The "triumph" of the "preferably not in public" mentality, both in the text and in society, is also illustrated by the interaction between the three narratives. In chapter, 5, in which "Hy staan by die deur en hy klop" is discussed, attention is focussed on the ironic function of the Biblical references, the contrast between Jan and the rest of society, and the way in which the "climax" is located within the Iserian "blank" in the text, so that the entire process of decoding is based on a filling in of that "blank" and its implications. "Gustav gaan speel" is based loosely on Barthes's lexia model, in order to determine the signifying process in the text, and also to demonstrate the way in which the text presupposes rereading. In the discussion of the title text it is revealed how the text is centered in the basic dichotomy between the narrator-as-writer and the journalist, and the way in which this polarity is relativized by the text as such. The text is demonstrated to be the credo of the volume as a whole as well as of the fiction of the Seventies in Afrikaans.
- Full Text:
- Date Issued: 1988
The integration of effluent treatment using constructed wetlands, with crop production and aquaculture
- Authors: de Jong, Martyn
- Date: 2019
- Subjects: Recycling (Waste, etc.) , Brewery waste , Sewage -- Purification , Beets , Mozambique tilapia
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/95767 , vital:31197
- Description: Breweries are major consumers of water and produce nutrient rich wastewater. Therefore, it is important to research technologies that optimise the reuse and recycling of this waste. This study compared different constructed wetlands (CWs) in terms of their potential for cleaning brewery effluent and simultaneously producing crops Beta vulgaris and fish Oreochromis mossambicus. Filling and draining times (FDT; 15 min, 30 min and 60 min) in tidal CWs were compared in Experiment 1. The 15 min FDT (6.52 ± 0.09 mg/l) and 30 min FDT (5.74 ± 0.09 mg/l) had higher dissolved oxygen (DO) than the 60 min FDT (5.40 ± 0.09 mg/l; p<0.05). This resulted in the 15 and 30 min FDT treatments reaching ammonia effluent discharge standards sooner than the 60 min FDT. Total plant harvest increased with increasing FDT; therefore, 15 min FDT was used as the FDT in tidal treatments in the following experiments. The aerated CW (5.81 ± 0.07 mg/l) and tidal CW (5.67 ± 0.07 mg/l) treatments had higher DO concentrations than the unaerated CW treatment (3.76 ± 0.07 mg/l; p<0.05) in Experiment 2. This resulted in lower ammonia concentrations on day 5 in the aerated and tidal CWs compared with the unaerated treatment (p<0.05). The tidal CW (23.97 ± 2.57 kg) had a total harvest that was approximately four times higher than the unaerated CW (p<0.05), which had the highest frequency of chlorosis and plant mortality; and was unable to treat ammonia to discharge standards. In Experiment 3, the aerated and tidal CW were compared with municipal-water as water sources for aquaculture. There were no differences in fish growth (p > 0.05). However, there were differences in water quality; with the municipal treatment having the lowest pH, EC and nitrate concentration (p<0.05); but all water quality parameters remained in a range suitably for fish production. Due to the tidal CW having the highest plant harvest and lowest frequency of chlorosis and mortality; it was the most suitable CW technology to clean the brewery effluent, and to produce B. vulgaris and water that could be used downstream in aquaculture.
- Full Text:
- Date Issued: 2019
- Authors: de Jong, Martyn
- Date: 2019
- Subjects: Recycling (Waste, etc.) , Brewery waste , Sewage -- Purification , Beets , Mozambique tilapia
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/95767 , vital:31197
- Description: Breweries are major consumers of water and produce nutrient rich wastewater. Therefore, it is important to research technologies that optimise the reuse and recycling of this waste. This study compared different constructed wetlands (CWs) in terms of their potential for cleaning brewery effluent and simultaneously producing crops Beta vulgaris and fish Oreochromis mossambicus. Filling and draining times (FDT; 15 min, 30 min and 60 min) in tidal CWs were compared in Experiment 1. The 15 min FDT (6.52 ± 0.09 mg/l) and 30 min FDT (5.74 ± 0.09 mg/l) had higher dissolved oxygen (DO) than the 60 min FDT (5.40 ± 0.09 mg/l; p<0.05). This resulted in the 15 and 30 min FDT treatments reaching ammonia effluent discharge standards sooner than the 60 min FDT. Total plant harvest increased with increasing FDT; therefore, 15 min FDT was used as the FDT in tidal treatments in the following experiments. The aerated CW (5.81 ± 0.07 mg/l) and tidal CW (5.67 ± 0.07 mg/l) treatments had higher DO concentrations than the unaerated CW treatment (3.76 ± 0.07 mg/l; p<0.05) in Experiment 2. This resulted in lower ammonia concentrations on day 5 in the aerated and tidal CWs compared with the unaerated treatment (p<0.05). The tidal CW (23.97 ± 2.57 kg) had a total harvest that was approximately four times higher than the unaerated CW (p<0.05), which had the highest frequency of chlorosis and plant mortality; and was unable to treat ammonia to discharge standards. In Experiment 3, the aerated and tidal CW were compared with municipal-water as water sources for aquaculture. There were no differences in fish growth (p > 0.05). However, there were differences in water quality; with the municipal treatment having the lowest pH, EC and nitrate concentration (p<0.05); but all water quality parameters remained in a range suitably for fish production. Due to the tidal CW having the highest plant harvest and lowest frequency of chlorosis and mortality; it was the most suitable CW technology to clean the brewery effluent, and to produce B. vulgaris and water that could be used downstream in aquaculture.
- Full Text:
- Date Issued: 2019
An investigation into the tax consequences for individuals performing work abroad
- Authors: De Ponte, Celeste Lidia
- Date: 2020
- Subjects: South Africa. Income Tax Act, 1962 , Income tax -- Law and legislation -- South Africa , Double taxation -- South Africa , International business enterprises -- Taxation -- Law and legislation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/141235 , vital:37955
- Description: This thesis considered the income tax implications for South African tax resident individuals who render services abroad. The research included an analysis of the impact that the amendment to the section 10(1)(o)(ii) exemption has on individuals rendering services abroad and companies who send their employees abroad. In doing so, this thesis sought to highlight the key factors for consideration, for both employers and individuals. A doctrinal methodology was applied, and an analysis was carried out of relevant tax legislation, commentary of experts in the field of tax law and the relevant case law of South Africa, the United Kingdom (UK), Australia and the United States of America (US), where relevant. It was established that residency is key to determining the tax liability of a person and has an impact on the relief mechanisms that are available where double taxation arises. In addition, the amendment to section 10(1)(o)(ii) was considered. It was concluded that when rendering services abroad, both the employer and employee need to consider the tax consequences that may arise and highlights the factors which may be relevant. The thesis illustrates that, whilst the R1 million exemption alleviates the double tax consequences to a certain extent, further guidance is needed as to how the R1 million threshold will be calculated.
- Full Text:
- Date Issued: 2020
- Authors: De Ponte, Celeste Lidia
- Date: 2020
- Subjects: South Africa. Income Tax Act, 1962 , Income tax -- Law and legislation -- South Africa , Double taxation -- South Africa , International business enterprises -- Taxation -- Law and legislation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/141235 , vital:37955
- Description: This thesis considered the income tax implications for South African tax resident individuals who render services abroad. The research included an analysis of the impact that the amendment to the section 10(1)(o)(ii) exemption has on individuals rendering services abroad and companies who send their employees abroad. In doing so, this thesis sought to highlight the key factors for consideration, for both employers and individuals. A doctrinal methodology was applied, and an analysis was carried out of relevant tax legislation, commentary of experts in the field of tax law and the relevant case law of South Africa, the United Kingdom (UK), Australia and the United States of America (US), where relevant. It was established that residency is key to determining the tax liability of a person and has an impact on the relief mechanisms that are available where double taxation arises. In addition, the amendment to section 10(1)(o)(ii) was considered. It was concluded that when rendering services abroad, both the employer and employee need to consider the tax consequences that may arise and highlights the factors which may be relevant. The thesis illustrates that, whilst the R1 million exemption alleviates the double tax consequences to a certain extent, further guidance is needed as to how the R1 million threshold will be calculated.
- Full Text:
- Date Issued: 2020
Ecological engineering: an assessment of the ecological impact of Reno mattress structures used in erosion control in the Keurbooms Estuary, South Africa
- Authors: De Villiers, Nina
- Date: 2020
- Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Keurboomstrand , Coast changes -- South Africa -- Keurboomstrand , Shore protection -- South Africa -- Keurboomstrand , Coastal engineering-- South Africa -- Keurboomstrand , Coastal zone management-- South Africa -- Keurboomstrand , Estuarine ecology-- South Africa -- Keurboomstrand , Eelgrass -- South Africa -- Keurboomstrand , Reno Mattresses
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166138 , vital:41332
- Description: Global climate changes have been associated with ocean warming and sea-level rise. Armouring of coastlines has become common practice with the increasing threat of coastal erosion. The transformation of soft sediment habitats to hard, artificial habitats because of coastline armouring can lead to changes in species diversity, composition and distribution. It is, therefore, essential to assess changes to habitats from coastal development as well as the ecological impact erosion control structures have within coastal systems. Ecological engineering attempts to combine engineering principals and ecological processes to reduce environmental impacts from coastal development and the implementation of artificial structures. Estuaries are particularly vulnerable to anthropogenic impacts through development, and are extremely important systems offering nursery and foraging grounds for many species. These systems are, however, particularly vulnerable to anthropogenic impacts from urbanisation and development. Within South Africa many estuaries are being transformed by the addition of artificial structures to combat erosion, one such structure is the Reno mattress (a flattened wire box filled with rocks). This study compared the fish diversity and abundances of existing Reno mattress structures and natural eelgrass (Zostera capensis) habitat in the Keurbooms Estuary, South Africa. Benthic invertebrates were sampled using standard core sampling and an adapted suction sampling approach within the two habitats. The non-destructive method of mini Baited Remote Underwater Video Systems (BRUVs) was used to sample fish. Seasonal benthic invertebrate and fish abundances and assemblages were assessed from winter 2018 to spring 2019 with greater abundances of both recorded in summer. Significantly greater abundances, diversity, and richness of fish were found in the Reno mattress habitat compared to Z. capensis. Invertebrate taxa displayed some overlap between habitats, however, three higher taxonomic groups were only recorded within Reno mattress habitat and one only within the eelgrass habitat. Fish assemblages differed significantly between the two established habitats. A Before-After-Control-Impact (BACI) investigation was used to assess the ecological impact of newly installed Reno mattresses in the Keurbooms Estuary. Zostera capensis extent was sampled by determining the percentage cover of 0.5 m X 0.5 m quadrats and measurements of eelgrass blades. Percentage cover and blade length decreased during the installation of Reno mattress, but then recovered shortly after completion of the installation. Abundances, richness and diversity of invertebrates and fish were found to be similar before and after the installation which suggests that the installation had no net negative impact on the site. The Reno mattresses were found to attract fauna typical of rocky shore environments as well as a few invasive alien invertebrate species. This study noted that a hybrid habitat of Reno mattress and eelgrass was created and may in fact provide the positives of both to a system. In any coastal development it will be important to balance the demands of a growing population and the protection of natural habitats. The results of this study suggest that complex artificial structures such as Reno mattresses do provide habitat for fish and invertebrates. However, the use of these structures should be in combination with natural vegetation (e.g. as a hybrid habitat) and not one that replaces intertidal and subtidal natural habitat especially eelgrass. There is limited information regarding the ecological impacts of using Reno mattresses in estuaries and this study provides new information on their ecological efficacy that should be valuable for future coastal erosion control practices.
- Full Text:
- Date Issued: 2020
- Authors: De Villiers, Nina
- Date: 2020
- Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Keurboomstrand , Coast changes -- South Africa -- Keurboomstrand , Shore protection -- South Africa -- Keurboomstrand , Coastal engineering-- South Africa -- Keurboomstrand , Coastal zone management-- South Africa -- Keurboomstrand , Estuarine ecology-- South Africa -- Keurboomstrand , Eelgrass -- South Africa -- Keurboomstrand , Reno Mattresses
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166138 , vital:41332
- Description: Global climate changes have been associated with ocean warming and sea-level rise. Armouring of coastlines has become common practice with the increasing threat of coastal erosion. The transformation of soft sediment habitats to hard, artificial habitats because of coastline armouring can lead to changes in species diversity, composition and distribution. It is, therefore, essential to assess changes to habitats from coastal development as well as the ecological impact erosion control structures have within coastal systems. Ecological engineering attempts to combine engineering principals and ecological processes to reduce environmental impacts from coastal development and the implementation of artificial structures. Estuaries are particularly vulnerable to anthropogenic impacts through development, and are extremely important systems offering nursery and foraging grounds for many species. These systems are, however, particularly vulnerable to anthropogenic impacts from urbanisation and development. Within South Africa many estuaries are being transformed by the addition of artificial structures to combat erosion, one such structure is the Reno mattress (a flattened wire box filled with rocks). This study compared the fish diversity and abundances of existing Reno mattress structures and natural eelgrass (Zostera capensis) habitat in the Keurbooms Estuary, South Africa. Benthic invertebrates were sampled using standard core sampling and an adapted suction sampling approach within the two habitats. The non-destructive method of mini Baited Remote Underwater Video Systems (BRUVs) was used to sample fish. Seasonal benthic invertebrate and fish abundances and assemblages were assessed from winter 2018 to spring 2019 with greater abundances of both recorded in summer. Significantly greater abundances, diversity, and richness of fish were found in the Reno mattress habitat compared to Z. capensis. Invertebrate taxa displayed some overlap between habitats, however, three higher taxonomic groups were only recorded within Reno mattress habitat and one only within the eelgrass habitat. Fish assemblages differed significantly between the two established habitats. A Before-After-Control-Impact (BACI) investigation was used to assess the ecological impact of newly installed Reno mattresses in the Keurbooms Estuary. Zostera capensis extent was sampled by determining the percentage cover of 0.5 m X 0.5 m quadrats and measurements of eelgrass blades. Percentage cover and blade length decreased during the installation of Reno mattress, but then recovered shortly after completion of the installation. Abundances, richness and diversity of invertebrates and fish were found to be similar before and after the installation which suggests that the installation had no net negative impact on the site. The Reno mattresses were found to attract fauna typical of rocky shore environments as well as a few invasive alien invertebrate species. This study noted that a hybrid habitat of Reno mattress and eelgrass was created and may in fact provide the positives of both to a system. In any coastal development it will be important to balance the demands of a growing population and the protection of natural habitats. The results of this study suggest that complex artificial structures such as Reno mattresses do provide habitat for fish and invertebrates. However, the use of these structures should be in combination with natural vegetation (e.g. as a hybrid habitat) and not one that replaces intertidal and subtidal natural habitat especially eelgrass. There is limited information regarding the ecological impacts of using Reno mattresses in estuaries and this study provides new information on their ecological efficacy that should be valuable for future coastal erosion control practices.
- Full Text:
- Date Issued: 2020
Generation of a virtual library of terpenes using graph theory, and its application in exploration of the mechanisms of terpene biosynthesis
- Authors: Dendera, Washington
- Date: 2020
- Subjects: Terpenes , Plants -- Metabolism , Computational biology , Bioinformatics , Organic compounds -- Synthesis , Monoterpenes , Molecular biology -- Computer simulation
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123453 , vital:35439
- Description: Terpenes form a large group of organic compounds which have proven to be of use to many living organisms being used by plants for metabolism (Pichersky and Gershenzon, 1934; McGarvey and Croteau, 1995; Gershenzon and Dudareva, 2007), defence or as a means to attract pollinators and also used by humans in medical, pharmaceutical and food industry (Bicas, Dionísio and Pastore, 2009; Marmulla and Harder, 2014; Kandi et al., 2015). Following on literature methods to generate chemical libraries using graph theoretic techniques, complete libraries of all possible terpene isomers have been constructed with the goal of construction of derivative libraries of possible carbocation intermediates which are important in the elucidation of mechanisms in the biosynthesis of terpenes. Virtual library generation of monoterpenes was first achieved by generating graphs of order 7, 8, 9 and 10 using the Nauty and Traces suite. These were screened and processed with a set of collated Python scripts written to recognize the graphs in text format and translate them to molecules, minimizing through Tinker whilst discarding graphs that violate chemistry laws. As a result of the computational time required only order 7 and order 10 graphs were processed. Out of the 873 graphs generated from order seven, 353 were converted to molecules and from the 11,7 million produced from order 10 half were processed resulting in the production of 442928 compounds (repeats included). For screening, 55 366 compounds were docked in the active site of limonene synthase; of these 2355 ligands had a good Vina docking score with a binding energy of between -7.0 and -7.4 kcal.mol-1. When these best docked molecules were overlaid in the active site a map of possible ligand positions within the active site of limonene synthase was traced out.
- Full Text:
- Date Issued: 2020
- Authors: Dendera, Washington
- Date: 2020
- Subjects: Terpenes , Plants -- Metabolism , Computational biology , Bioinformatics , Organic compounds -- Synthesis , Monoterpenes , Molecular biology -- Computer simulation
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123453 , vital:35439
- Description: Terpenes form a large group of organic compounds which have proven to be of use to many living organisms being used by plants for metabolism (Pichersky and Gershenzon, 1934; McGarvey and Croteau, 1995; Gershenzon and Dudareva, 2007), defence or as a means to attract pollinators and also used by humans in medical, pharmaceutical and food industry (Bicas, Dionísio and Pastore, 2009; Marmulla and Harder, 2014; Kandi et al., 2015). Following on literature methods to generate chemical libraries using graph theoretic techniques, complete libraries of all possible terpene isomers have been constructed with the goal of construction of derivative libraries of possible carbocation intermediates which are important in the elucidation of mechanisms in the biosynthesis of terpenes. Virtual library generation of monoterpenes was first achieved by generating graphs of order 7, 8, 9 and 10 using the Nauty and Traces suite. These were screened and processed with a set of collated Python scripts written to recognize the graphs in text format and translate them to molecules, minimizing through Tinker whilst discarding graphs that violate chemistry laws. As a result of the computational time required only order 7 and order 10 graphs were processed. Out of the 873 graphs generated from order seven, 353 were converted to molecules and from the 11,7 million produced from order 10 half were processed resulting in the production of 442928 compounds (repeats included). For screening, 55 366 compounds were docked in the active site of limonene synthase; of these 2355 ligands had a good Vina docking score with a binding energy of between -7.0 and -7.4 kcal.mol-1. When these best docked molecules were overlaid in the active site a map of possible ligand positions within the active site of limonene synthase was traced out.
- Full Text:
- Date Issued: 2020
Investigating assay formats for screening malaria Hsp90-Hop interaction inhibitors
- Authors: Derry, Leigh-Anne Tracy Kim
- Date: 2019
- Subjects: Antimalarials , Heat shock proteins , Drug interactions , Drug resistance , Plasmodium falciparum , High throughput screening (Drug development) , Bioluminescence resonance energy transfer (BRET) , Fluorescence resonance energy transfer (FRET)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63345 , vital:28395
- Description: Although significant gains have been made in the combat against malaria in the last decade, the persistent threat of drug and insecticide resistance continues to motivate the search for new classes of antimalarial drug compounds and targets. Due to their predominance in cellular reactions, protein-protein interactions (P-PIs) are emerging as a promising general target class for therapeutic development. The P-PI which is the focus of this project is the interaction between the chaperone heat shock protein 90 (Hsp90) and its co-chaperone Hsp70/Hsp90 organising protein (Hop). Hop binds to Hsp70 and Hsp90 and facilitates the transfer of client proteins (proteins undergoing folding) from the former to the latter and also regulates nucleotide exchange on Hsp90. Due to its role in correcting protein misfolding during cell stress, Hsp90 is being pursued as a cancer drug target and compounds that inhibit its ATPase activity have entered clinical trials. However, it has been proposed that inhibiting the interaction between Hsp90 and Hop may be alternative approach for inhibiting Hsp90 function for cancer therapy. The malaria parasite Plasmodium falciparum experiences temperature fluctuations during vector-host transitions and febrile episodes and cell stress due to rapid growth and immune responses. Hence, it also depends on chaperones, including PfHsp90, to maintain protein functionality and pathogenesis, demonstrated inter alia by the sensitivity of parasites to Hsp90 inhibitors. In addition, PfHsp90 exists as a complex with the malarial Hop homologue, PfHop, in parasite lysates. Consequently, the purpose of this study was to explore P-PI assay formats that can confirm the interaction of PfHsp90 and PfHop and can be used to identify inhibitors of the interaction, preferably in a medium- to high-throughput screening mode. As a first approach, cell-based bioluminescence and fluorescence resonance energy transfer (BRET and FRET) assays were performed in HeLa cells. To facilitate this, expression plasmid constructs containing coding sequences of P. falciparum and mammalian Hsp90 and Hop and their interacting domains (Hsp90 C-domain and Hop TPR2A domain) fused to the BRET and FRET reporter proteins – yellow fluorescent protein (YFP), cyan fluorescent protein (CFP) and Renilla luciferase (Rluc) - were prepared and used for HeLa cell transient transfections. The FRET assay produced positive interaction signals for the full-length P. falciparum and mammalian Hsp90-Hop interactions. However, C-domain-TPR2A domain interactions were not detected, no interactions could be demonstrated with the BRET assay and western blotting experiments failed to detect expression of all the interaction partners in transiently transfected HeLa cells. Consequently, an alternative in vitro FRET assay format using recombinant proteins was investigated. Expression constructs for the P. falciparum and mammalian C-domains and TPR2A domains fused respectively to YFP and CFP were prepared and the corresponding fusion proteins expressed and purified from E. coli. No interaction was found with the mammalian interaction partners, but interaction of the P. falciparum C-domain and TPR2A domain was consistently detected with a robust Z’ factor value of 0.54. A peptide corresponding to the PfTPR2A domain sequence primarily responsible for Hsp90 binding (based on a human TPR2A peptide described by Horibe et al., 2011) was designed and showed dose-dependent inhibition of the interaction, with 53.7% inhibition at 100 μM. The components of the assay are limited to the purified recombinant proteins, requires minimal liquid steps and may thus be a useful primary screening format for identifying inhibitors of P. falciparum Hsp90-Hop interaction.
- Full Text:
- Date Issued: 2019
- Authors: Derry, Leigh-Anne Tracy Kim
- Date: 2019
- Subjects: Antimalarials , Heat shock proteins , Drug interactions , Drug resistance , Plasmodium falciparum , High throughput screening (Drug development) , Bioluminescence resonance energy transfer (BRET) , Fluorescence resonance energy transfer (FRET)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63345 , vital:28395
- Description: Although significant gains have been made in the combat against malaria in the last decade, the persistent threat of drug and insecticide resistance continues to motivate the search for new classes of antimalarial drug compounds and targets. Due to their predominance in cellular reactions, protein-protein interactions (P-PIs) are emerging as a promising general target class for therapeutic development. The P-PI which is the focus of this project is the interaction between the chaperone heat shock protein 90 (Hsp90) and its co-chaperone Hsp70/Hsp90 organising protein (Hop). Hop binds to Hsp70 and Hsp90 and facilitates the transfer of client proteins (proteins undergoing folding) from the former to the latter and also regulates nucleotide exchange on Hsp90. Due to its role in correcting protein misfolding during cell stress, Hsp90 is being pursued as a cancer drug target and compounds that inhibit its ATPase activity have entered clinical trials. However, it has been proposed that inhibiting the interaction between Hsp90 and Hop may be alternative approach for inhibiting Hsp90 function for cancer therapy. The malaria parasite Plasmodium falciparum experiences temperature fluctuations during vector-host transitions and febrile episodes and cell stress due to rapid growth and immune responses. Hence, it also depends on chaperones, including PfHsp90, to maintain protein functionality and pathogenesis, demonstrated inter alia by the sensitivity of parasites to Hsp90 inhibitors. In addition, PfHsp90 exists as a complex with the malarial Hop homologue, PfHop, in parasite lysates. Consequently, the purpose of this study was to explore P-PI assay formats that can confirm the interaction of PfHsp90 and PfHop and can be used to identify inhibitors of the interaction, preferably in a medium- to high-throughput screening mode. As a first approach, cell-based bioluminescence and fluorescence resonance energy transfer (BRET and FRET) assays were performed in HeLa cells. To facilitate this, expression plasmid constructs containing coding sequences of P. falciparum and mammalian Hsp90 and Hop and their interacting domains (Hsp90 C-domain and Hop TPR2A domain) fused to the BRET and FRET reporter proteins – yellow fluorescent protein (YFP), cyan fluorescent protein (CFP) and Renilla luciferase (Rluc) - were prepared and used for HeLa cell transient transfections. The FRET assay produced positive interaction signals for the full-length P. falciparum and mammalian Hsp90-Hop interactions. However, C-domain-TPR2A domain interactions were not detected, no interactions could be demonstrated with the BRET assay and western blotting experiments failed to detect expression of all the interaction partners in transiently transfected HeLa cells. Consequently, an alternative in vitro FRET assay format using recombinant proteins was investigated. Expression constructs for the P. falciparum and mammalian C-domains and TPR2A domains fused respectively to YFP and CFP were prepared and the corresponding fusion proteins expressed and purified from E. coli. No interaction was found with the mammalian interaction partners, but interaction of the P. falciparum C-domain and TPR2A domain was consistently detected with a robust Z’ factor value of 0.54. A peptide corresponding to the PfTPR2A domain sequence primarily responsible for Hsp90 binding (based on a human TPR2A peptide described by Horibe et al., 2011) was designed and showed dose-dependent inhibition of the interaction, with 53.7% inhibition at 100 μM. The components of the assay are limited to the purified recombinant proteins, requires minimal liquid steps and may thus be a useful primary screening format for identifying inhibitors of P. falciparum Hsp90-Hop interaction.
- Full Text:
- Date Issued: 2019
Using four different methods to reach a taxonomic conclusion in dung beetles (Scarabaeinae)
- Authors: Deschodt, Christian Michel
- Date: 2019
- Subjects: Dung beetles -- Classification , Scarabaeidae -- Classification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67845 , vital:29156
- Description: Four different techniques to make taxonomic decisions concerning different species in Scarabaeinae are being investigated. Firstly, I made measurements of the body dimensions which are plotted on a two dimensional graph. This method is successfully used to erect one new species, Copris crassus Deschodt and Davis, 2015, and to establish the synonymy of Copris bihamatus Balthasar, 1965 with Copris fidius (Olivier, 1789). Thereafter the classical or traditional comparative method is used to propose seven new species Scarabaeolus soutpansbergensis (Deschodt and Davis 2015), Scarabaeolus megaparvulus (Davis and Deschodt 2015), Scarabaeolus niemandi (Deschodt and Davis 2015), Scarabaeolus carniphilus (Davis and Deschodt 2015), Scarabaeolus ermienae (Deschodt and Davis 2015), Scarabaeolus planipennis (Davis and Deschodt 2015) and Scarabaeolus afronitidus (Davis and Deschodt 2015) and formally synonymise Scarabaeolus vansoni (Ferreira, 1958) with Scarabaeolus lucidulus (Boheman, 1860) and Scarabaeolus xavieri (Ferreira, 1968) with Scarabaeolus andreaei (zur Strassen, 1963). Morphometric measurements of external structures of a group of flightless relict beetles in the tribe Canthonini are used to compile a nexus file which is analysed with computer software. The interpretation of these results is used here to support the erection of a new genus Drogo Deschodt, Davis & Scholtz 2016, Lastly I analysed the DNA sequences of specimens from different species belonging to a species complex in the genus Epirinus Reiche, 1841 occurring over a wide geographic range. These sequences are used together with external morphological characters to propose the synonymy of Epirinus hluhluwensis Medina & Scholtz 2005 and Epirinus ngomae Medina & Scholtz 2005 with Epirinus davisi Scholtz & Howden 1987.
- Full Text:
- Date Issued: 2019
- Authors: Deschodt, Christian Michel
- Date: 2019
- Subjects: Dung beetles -- Classification , Scarabaeidae -- Classification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67845 , vital:29156
- Description: Four different techniques to make taxonomic decisions concerning different species in Scarabaeinae are being investigated. Firstly, I made measurements of the body dimensions which are plotted on a two dimensional graph. This method is successfully used to erect one new species, Copris crassus Deschodt and Davis, 2015, and to establish the synonymy of Copris bihamatus Balthasar, 1965 with Copris fidius (Olivier, 1789). Thereafter the classical or traditional comparative method is used to propose seven new species Scarabaeolus soutpansbergensis (Deschodt and Davis 2015), Scarabaeolus megaparvulus (Davis and Deschodt 2015), Scarabaeolus niemandi (Deschodt and Davis 2015), Scarabaeolus carniphilus (Davis and Deschodt 2015), Scarabaeolus ermienae (Deschodt and Davis 2015), Scarabaeolus planipennis (Davis and Deschodt 2015) and Scarabaeolus afronitidus (Davis and Deschodt 2015) and formally synonymise Scarabaeolus vansoni (Ferreira, 1958) with Scarabaeolus lucidulus (Boheman, 1860) and Scarabaeolus xavieri (Ferreira, 1968) with Scarabaeolus andreaei (zur Strassen, 1963). Morphometric measurements of external structures of a group of flightless relict beetles in the tribe Canthonini are used to compile a nexus file which is analysed with computer software. The interpretation of these results is used here to support the erection of a new genus Drogo Deschodt, Davis & Scholtz 2016, Lastly I analysed the DNA sequences of specimens from different species belonging to a species complex in the genus Epirinus Reiche, 1841 occurring over a wide geographic range. These sequences are used together with external morphological characters to propose the synonymy of Epirinus hluhluwensis Medina & Scholtz 2005 and Epirinus ngomae Medina & Scholtz 2005 with Epirinus davisi Scholtz & Howden 1987.
- Full Text:
- Date Issued: 2019
Biotechnology from bench to market: the design, scale-up and commercialisation strategy development of a disruptive bioprocess for potable ethanol production
- Authors: Dhanani, Karim Colin Hassan
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/55863 , vital:26750
- Description: The capacity of research institutions to engage in technology transfer activities has important implications on both economic development and technological advancement. This thesis explores the developmental and commercialisation processes involved in the transfer of a potentially disruptive bioprocessing technology for beverage alcohol production. Ethanolic fermentation strategies are of interest due to their global economic importance and their potential to produce clean renewable fuels in the future. Currently used methods are both energetically wasteful and economically inefficient. To this end more effective bioprocessing methods and implementation strategies are required to enable commercially viable decentralised small-scale ethanol production. Perfusion reactors have a number of advantages over batch and other continuous fermentation strategies. This study aimed to develop and study the fermentative efficiency of a perfusion tower bioreactor system at the bench scale, and subsequently through a scale up process to a low level commercial capacity. An HPLC method was developed for the Simultaneous quantification of common fermentation analytes; this was used to determine bench scale fermentation efficacies over an operational period. At steady state the ethanol volumetric productivity of the bench scale bioreactor system was 3.40 g. L-1.h-1, the average yield of ethanol to consumed sugar was 0.467 g.g -1, with an average sugar conversion percentage of 96%. Results showed that the tower perfusion bioreactor was appropriate for high performance ethyl alcohol fermentations. This reactor design was then scaled up to pilot scale and then commercial scale ca pacity. Similar efficienCies were achieved with these larger systems. Based on the process performance data obtained, a commercialisation strategy was developed and market performance was projected. It was found that productivity rates per unit volume were favourable, and the bioreactor system was determined to be very cost effective for a decentralised ethanolic beverage manufacturing model.
- Full Text:
- Date Issued: 2015
- Authors: Dhanani, Karim Colin Hassan
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/55863 , vital:26750
- Description: The capacity of research institutions to engage in technology transfer activities has important implications on both economic development and technological advancement. This thesis explores the developmental and commercialisation processes involved in the transfer of a potentially disruptive bioprocessing technology for beverage alcohol production. Ethanolic fermentation strategies are of interest due to their global economic importance and their potential to produce clean renewable fuels in the future. Currently used methods are both energetically wasteful and economically inefficient. To this end more effective bioprocessing methods and implementation strategies are required to enable commercially viable decentralised small-scale ethanol production. Perfusion reactors have a number of advantages over batch and other continuous fermentation strategies. This study aimed to develop and study the fermentative efficiency of a perfusion tower bioreactor system at the bench scale, and subsequently through a scale up process to a low level commercial capacity. An HPLC method was developed for the Simultaneous quantification of common fermentation analytes; this was used to determine bench scale fermentation efficacies over an operational period. At steady state the ethanol volumetric productivity of the bench scale bioreactor system was 3.40 g. L-1.h-1, the average yield of ethanol to consumed sugar was 0.467 g.g -1, with an average sugar conversion percentage of 96%. Results showed that the tower perfusion bioreactor was appropriate for high performance ethyl alcohol fermentations. This reactor design was then scaled up to pilot scale and then commercial scale ca pacity. Similar efficienCies were achieved with these larger systems. Based on the process performance data obtained, a commercialisation strategy was developed and market performance was projected. It was found that productivity rates per unit volume were favourable, and the bioreactor system was determined to be very cost effective for a decentralised ethanolic beverage manufacturing model.
- Full Text:
- Date Issued: 2015