Curriculum outcomes, teaching practices and learner competencies in isiXhosa in three Grahamstown schools
- Authors: Fobe, Mila Pamella
- Date: 2014
- Subjects: Xhosa language -- Study and teaching (Primary) -- South Africa -- Grahamstown Xhosa language -- Study and teaching (Secondary) -- South Africa -- Grahamstown Language and education -- South Africa -- Grahamstown Curriculum planning Second language acquisition Public schools -- South Africa -- Grahamstown Language policy -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3630 , http://hdl.handle.net/10962/d1012072
- Description: This study looks at the curriculum outcomes, teaching practices and learner competencies in isiXhosa at three Eastern Cape schools and across three different grades, 7-9. It explores the link between language learning and teaching as well as the teaching strategies used within the classroom. In particular, the study seeks to analyse how isiXhosa is taught at three different levels of instruction, namely at Home Language (HL), First Additional Language (FAL) and Second Additional Language (SAL) levels. Qualitative methods were used, and the study took the form of interpretive case studies within the respective schools. The purpose of using multiple case studies was to investigate the reality within the three sites selected. The three schools had three extreme settings, in the sense that one of the schools is a rich isiXhosa environment and the other two schools are English environments. The tools used for data gathering were interviews, classroom observations, and an analysis of documents from the Department of Basic Education. Data was then presented and analysed in Chapter 4 and 5 against the backdrop of an extensive literature review in Chapter 2 as well as a detailed methodological approach as outlined in Chapter 3. One of the findings of this research indicates that in two of the schools the teaching culture is largely from a western perspective, whereas in one of the schools the learners are primarily isiXhosa speaking and teachers use a different linguistic approach to imparting knowledge. In the private and ex-Model C school it was found that a lack of exposure to isiXhosa is the primary cause of language problems for L2 learners. Secondly the L1 is not appropriately maintained or promoted in the school environment because it is presumed that learners are sufficiently exposed to their L1 at home. The research found therefore that in this particular schooling environment there is an inconsistency between the curricula that is taught in relation to the linguistic abilities of the learners, many of whom are mother tongue speakers of isiXhosa. Furthermore and more generally, it was found that teachers are still not well informed concerning South Africa’s Language-in-Education-Policy and there is a need for more inservice training that will focus on the nature of additional language acquisition in order to address the challenges of teaching these languages. The thesis concludes that extensive work needs to be done in order to reposition the teaching of isiXhosa at all three levels, but particularly at FAL level. This research shows that there is a disjuncture between the proposed curriculum/learning outcomes and the standards or levels achieved by the learners, more especially at FAL and SAL where oral proficiency in isiXhosa remains a challenge. Specific recommendations are contained in the final chapter of the thesis which also makes reference to the draft policy of the Ministry of Basic Education regarding the incremental introduction of the teaching of African languages from 2014 onwards. This thesis also makes takes as a point of departure the importance of multilingualism in a multicultural society such as South Africa where language is suggested as a strong factor in the fostering of social cohesion. It is for this reason that the thesis argues that the expert teaching of African languages, in this case isiXhosa, at both mother tongue and second language levels is of fundamental importance to the future of South African society.
- Full Text:
- Date Issued: 2014
- Authors: Fobe, Mila Pamella
- Date: 2014
- Subjects: Xhosa language -- Study and teaching (Primary) -- South Africa -- Grahamstown Xhosa language -- Study and teaching (Secondary) -- South Africa -- Grahamstown Language and education -- South Africa -- Grahamstown Curriculum planning Second language acquisition Public schools -- South Africa -- Grahamstown Language policy -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3630 , http://hdl.handle.net/10962/d1012072
- Description: This study looks at the curriculum outcomes, teaching practices and learner competencies in isiXhosa at three Eastern Cape schools and across three different grades, 7-9. It explores the link between language learning and teaching as well as the teaching strategies used within the classroom. In particular, the study seeks to analyse how isiXhosa is taught at three different levels of instruction, namely at Home Language (HL), First Additional Language (FAL) and Second Additional Language (SAL) levels. Qualitative methods were used, and the study took the form of interpretive case studies within the respective schools. The purpose of using multiple case studies was to investigate the reality within the three sites selected. The three schools had three extreme settings, in the sense that one of the schools is a rich isiXhosa environment and the other two schools are English environments. The tools used for data gathering were interviews, classroom observations, and an analysis of documents from the Department of Basic Education. Data was then presented and analysed in Chapter 4 and 5 against the backdrop of an extensive literature review in Chapter 2 as well as a detailed methodological approach as outlined in Chapter 3. One of the findings of this research indicates that in two of the schools the teaching culture is largely from a western perspective, whereas in one of the schools the learners are primarily isiXhosa speaking and teachers use a different linguistic approach to imparting knowledge. In the private and ex-Model C school it was found that a lack of exposure to isiXhosa is the primary cause of language problems for L2 learners. Secondly the L1 is not appropriately maintained or promoted in the school environment because it is presumed that learners are sufficiently exposed to their L1 at home. The research found therefore that in this particular schooling environment there is an inconsistency between the curricula that is taught in relation to the linguistic abilities of the learners, many of whom are mother tongue speakers of isiXhosa. Furthermore and more generally, it was found that teachers are still not well informed concerning South Africa’s Language-in-Education-Policy and there is a need for more inservice training that will focus on the nature of additional language acquisition in order to address the challenges of teaching these languages. The thesis concludes that extensive work needs to be done in order to reposition the teaching of isiXhosa at all three levels, but particularly at FAL level. This research shows that there is a disjuncture between the proposed curriculum/learning outcomes and the standards or levels achieved by the learners, more especially at FAL and SAL where oral proficiency in isiXhosa remains a challenge. Specific recommendations are contained in the final chapter of the thesis which also makes reference to the draft policy of the Ministry of Basic Education regarding the incremental introduction of the teaching of African languages from 2014 onwards. This thesis also makes takes as a point of departure the importance of multilingualism in a multicultural society such as South Africa where language is suggested as a strong factor in the fostering of social cohesion. It is for this reason that the thesis argues that the expert teaching of African languages, in this case isiXhosa, at both mother tongue and second language levels is of fundamental importance to the future of South African society.
- Full Text:
- Date Issued: 2014
Isolation and characterization of genes encoding heat shock protein 70s (hsp 70s) from two species of the coelacanth, Latimeria chalumnae and Latimeria menadoensis
- Modisakeng, Keoagile William
- Authors: Modisakeng, Keoagile William
- Date: 2007
- Subjects: Coelacanth Coelacanth -- Genetics Heat shock proteins Molecular chaperones Proteins -- Analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3971 , http://hdl.handle.net/10962/d1004030
- Description: The extant coelacanths have a close resemblance to the coelacanth fossil records dating back to 230mya. Like their predecessors, the extant coelacanths inhabit rocky caves at a depth of 100-300m below sea level. In the Comoros, the water temperature at these depths is estimated to fluctuate between 14-20°C. High-level adaptation to these environment and lack of competition are thought to have led to the morphological uniformity and slow change throughout the history of the coelacanths. Under stress conditions, proteins unfold or misfold leading to the formation of aggregates. Molecular chaperones facilitate the correct folding of other proteins so that they can attain a stable tertiary structure. In addition, molecular chaperones aid the refolding of denatured proteins and the degradation of terminally misfolded protein after cellular stress. Heat shock proteins form one of the major classes of molecular chaperones. Here we show that, despite high-level adaptation to a unique habitat and slow change, the genome of the coelacanth encodes the major and highly conserved molecular chaperone, Hsp70. Latimeria menadoensis and Latimeria chalumnae contain intronless hsp70 genes encoding Hsp70 proteins archetypal of known Hsp70s. Based on the coelacanth codon usage, we have shown that bacterial protein expression systems, particularly Escherichia coli, may not be appropriate for the overproduction of coelacanth Hsp70s and coelacanth proteins in general. Also interesting, was the discovery that like the rat Hsc70, the L. menadoensis Hsp70 could not reverse thermal sensitivity in a temperate sensitive E. coli DnaK mutant strain, BB2362. We also report the successful isolation of a 1.2 kb region of L. menadoensis hsp70 upstream regulatory region. This region contain three putative heat shock elements, a TATA- box and two CAAT-boxes. This regulatory region resembled the Xenopus, mouse, and particularly tilapia hsp70 promoters, all of which have been shown to drive the expression of reporter genes in a heat dependent manner. Taken together, this data is the first to strongly suggest an inducible Hsp70-base cytoprotection mechanism in the coelacanth. It further provides basis to formulate testable predictions about the regulation, structure and function of Hsp70s in the living fossil, Latimeria.
- Full Text:
- Date Issued: 2007
- Authors: Modisakeng, Keoagile William
- Date: 2007
- Subjects: Coelacanth Coelacanth -- Genetics Heat shock proteins Molecular chaperones Proteins -- Analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3971 , http://hdl.handle.net/10962/d1004030
- Description: The extant coelacanths have a close resemblance to the coelacanth fossil records dating back to 230mya. Like their predecessors, the extant coelacanths inhabit rocky caves at a depth of 100-300m below sea level. In the Comoros, the water temperature at these depths is estimated to fluctuate between 14-20°C. High-level adaptation to these environment and lack of competition are thought to have led to the morphological uniformity and slow change throughout the history of the coelacanths. Under stress conditions, proteins unfold or misfold leading to the formation of aggregates. Molecular chaperones facilitate the correct folding of other proteins so that they can attain a stable tertiary structure. In addition, molecular chaperones aid the refolding of denatured proteins and the degradation of terminally misfolded protein after cellular stress. Heat shock proteins form one of the major classes of molecular chaperones. Here we show that, despite high-level adaptation to a unique habitat and slow change, the genome of the coelacanth encodes the major and highly conserved molecular chaperone, Hsp70. Latimeria menadoensis and Latimeria chalumnae contain intronless hsp70 genes encoding Hsp70 proteins archetypal of known Hsp70s. Based on the coelacanth codon usage, we have shown that bacterial protein expression systems, particularly Escherichia coli, may not be appropriate for the overproduction of coelacanth Hsp70s and coelacanth proteins in general. Also interesting, was the discovery that like the rat Hsc70, the L. menadoensis Hsp70 could not reverse thermal sensitivity in a temperate sensitive E. coli DnaK mutant strain, BB2362. We also report the successful isolation of a 1.2 kb region of L. menadoensis hsp70 upstream regulatory region. This region contain three putative heat shock elements, a TATA- box and two CAAT-boxes. This regulatory region resembled the Xenopus, mouse, and particularly tilapia hsp70 promoters, all of which have been shown to drive the expression of reporter genes in a heat dependent manner. Taken together, this data is the first to strongly suggest an inducible Hsp70-base cytoprotection mechanism in the coelacanth. It further provides basis to formulate testable predictions about the regulation, structure and function of Hsp70s in the living fossil, Latimeria.
- Full Text:
- Date Issued: 2007
An investigation of Wikipedia translation as an additive pedagogy for Oshikwanyama first language learning
- Authors: Hautemo, Aletta Mweneni
- Date: 2014
- Subjects: Kuanyama language -- Study and teaching (Secondary) -- Computer-assisted instruction , Kuanyama language -- Machine translating -- Namibia , Language and languages -- Study and teaching (Secondary) -- Computer-assisted instruction , Computer-assisted instruction -- Study and teaching (Secondary) -- Namibia , Information technology -- Study and teaching (Secondary) -- Namibia , Educational technology -- Namibia , Wikipedia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1982 , http://hdl.handle.net/10962/d1013139
- Description: The integration of Information and Communication Technology in the indigenous language classroom lags behind compared to other subjects. In many ways, indigenous language teachers find it difficult and to some extent, impossible to integrate ICT into their classroom activities. The focus of this study is to explore the ways in which ICT could be used as a learning tool in an Oshikwanyama First Language classroom. I investigated the use of Wikipedia translation as an additional teaching and learning tool. I concentrated on the impact that ICT tools have on learning, and the motivation it has on learners to learn Oshikwanyama. This qualitative case study was conducted in an urban school in northern Namibia. The adoption of ICT at the school is good as there is a full-fledged computer lab with unlimited wireless internet access. This was a requirement for the project to enable the participants to work online. I purposefully chose higher-level learners (Secondary phase) for this study. I conducted a survey with them on their access to and use of ICT devices in their daily lives, and thereafter conducted a basic computer workshop and a Wikipedia translation project with them. My research findings show that although the use of ICT is part of the learners’ lives, most of the communication through ICT devices is done in English not Oshikwanyama. Wikipedia translation offers a stimulating learning platform for learners to learn Oshikwanyama and English at the same time and this improved their performance in both languages. Furthermore, the Wikipedia translation, which was done collaboratively, gave learners the confidence to work with other learners to create knowledge. Lastly, Wikipedia translation motivates learners to learn Oshikwanyama and use it in their daily ICT interaction.
- Full Text:
- Date Issued: 2014
- Authors: Hautemo, Aletta Mweneni
- Date: 2014
- Subjects: Kuanyama language -- Study and teaching (Secondary) -- Computer-assisted instruction , Kuanyama language -- Machine translating -- Namibia , Language and languages -- Study and teaching (Secondary) -- Computer-assisted instruction , Computer-assisted instruction -- Study and teaching (Secondary) -- Namibia , Information technology -- Study and teaching (Secondary) -- Namibia , Educational technology -- Namibia , Wikipedia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1982 , http://hdl.handle.net/10962/d1013139
- Description: The integration of Information and Communication Technology in the indigenous language classroom lags behind compared to other subjects. In many ways, indigenous language teachers find it difficult and to some extent, impossible to integrate ICT into their classroom activities. The focus of this study is to explore the ways in which ICT could be used as a learning tool in an Oshikwanyama First Language classroom. I investigated the use of Wikipedia translation as an additional teaching and learning tool. I concentrated on the impact that ICT tools have on learning, and the motivation it has on learners to learn Oshikwanyama. This qualitative case study was conducted in an urban school in northern Namibia. The adoption of ICT at the school is good as there is a full-fledged computer lab with unlimited wireless internet access. This was a requirement for the project to enable the participants to work online. I purposefully chose higher-level learners (Secondary phase) for this study. I conducted a survey with them on their access to and use of ICT devices in their daily lives, and thereafter conducted a basic computer workshop and a Wikipedia translation project with them. My research findings show that although the use of ICT is part of the learners’ lives, most of the communication through ICT devices is done in English not Oshikwanyama. Wikipedia translation offers a stimulating learning platform for learners to learn Oshikwanyama and English at the same time and this improved their performance in both languages. Furthermore, the Wikipedia translation, which was done collaboratively, gave learners the confidence to work with other learners to create knowledge. Lastly, Wikipedia translation motivates learners to learn Oshikwanyama and use it in their daily ICT interaction.
- Full Text:
- Date Issued: 2014
Bioaccumulation and histopathology of copper in Oreochromis mossambicus
- Authors: Naigaga, Irene
- Date: 2003
- Subjects: Mozambique tilapia , Copper , Marine toxins , Fishes -- Effect of water pollution on , Water -- Pollution -- Environmental aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5234 , http://hdl.handle.net/10962/d1005077 , Mozambique tilapia , Copper , Marine toxins , Fishes -- Effect of water pollution on , Water -- Pollution -- Environmental aspects
- Description: Cu is one of the most toxic elements that affect fish populations when the fish are exposed to concentrations exceeding their tolerance. To investigate the effects of elementary Cu on aspects of bioconcentration, histology and behaviour, O. mossambicus were exposed to 0 and 0.75 ± 0.20 mg/l of Cu for 96 hours (short-term study), and 0, 0.11 ± 0.02, 0.29 ± 0.02, and 0.47 ± 0.04 mg/l of Cu for 64 days (longterm study) under controlled conditions in the laboratory. For the long-term study fish were sampled for gills, liver, and kidney Cu accumulation analysis after 1, 32 and 64 days of exposure and after 1, 2, 4, 16, 32, and 64 days for gills, liver and spleen histology analysis. Cu accumulation was concentration-duration dependent with the highest accumulation capacity in the liver. A multifactor linear model was developed for the relationship between exposure dose, exposure duration and Cu accumulation in the organs with the liver model: Log L = 3.35 + 0.85W + 0.31T (r² = 0.892) giving a better fit than the gills: G = −35.09 + 10.58W + 17.58T (r² = 0.632). Where L = Cu accumulation values in the liver, G = Cu accumulation values in the gills (both in μg/g dry mass); W = exposure dose in water (mg/l); and T = exposure time (days). Using this model Cu accumulation in organs can be estimated when exposure concentration and duration is known. This model should be tested under different conditions to determine the potential of the model in monitoring Cu toxicity in the environment. Lesions were observed in the liver, gills and spleen in all Cu treatments at all exposure concentration and exposure durations. However, the incidence and the degree of alteration was related to the concentration of Cu and duration of exposure. The sequential appearance of lesions in the order of, hepatic vacuolar degeneration, fatty degeneration and necrosis indicated a gradual increase in liver damage with larger duration of exposure time and increasing Cu concentration. The initial lesions in the gills were manifested as hypertrophy and hyperplasia of the gill epithelium causing increase in the thickness of the secondary lamellae, mucous cell hypertrophy and proliferation, mucous hypersecretion, proliferation of eosinophilic granule cells and hyperplasia of interlamellar cells. With increase in exposure time, necrosis of the eosinophilic granule cells, lamellar oedema, epithelial desquamation and increase in severity of lamellar hyperplasia were observed. These lesions indicated an initial defence mechanism of the fish against Cu toxicity followed by advanced histological changes that were related to Cu concentration and duration of exposure. Changes in the spleen were haemosiderosis, increase in the white pulp and macrophage centres, reduction in the red pulp, and necrosis suggesting that fish exposed to environmentally relevant levels of Cu may be histopathologically altered leading to anaemia and immunosuppression. Regression analysis was used to quantify the relationship between the total activity of the fish, and duration of exposure. There was a gradual decline in fish activity related to Cu concentration and duration of exposure before introducing food into the tanks. There was a constant activity after introducing food in the tanks at the control and 0.11 ± 0.02 mg/l Cu exposure levels irrespective of exposure time. Analysis of covariance (ANCOVA) was used to test for the difference in slopes between treatments. There was no significant difference (p > 0.05) between slopes of the control and 0.11 ± 0.02 mg/l Cu, and between 0.29 ± 0.02 and 47 ± 0.04 mg/l Cu before and after introducing food in the tanks. The slopes of both the control and 0.11 ± 0.02 mg/l Cu were significantly different from those of 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu (p < 0.05). There were significant differences in the mean opercular movements per minute between treatments (p < 0.05). There was hyperventilation at 0.11 ± 0.02 mg/l Cu i.e. 87 ± 18 opercular movements per minute (mean ± standard deviation) and hypoventilation at 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu i.e. 37 ± 34 and 13 ± 6 opercular movements per minute compared to the control. Hypo- and hyperventilation were related to the lesser and greater gill damage, respectively. In conclusion Cu accumulation and effects on histology of the liver, gills and were related to the concentration of Cu in the water and duration of exposure showing a gradual increase in incidence and intensity with larger duration of exposure time and increasing Cu concentration. The fish were initially able to homeostatically regulate and detoxify Cu. However, as the exposure continued, the homeostatic mechanism appears to have failed to cope with the increasing metal burden causing advanced histological changes.
- Full Text:
- Date Issued: 2003
- Authors: Naigaga, Irene
- Date: 2003
- Subjects: Mozambique tilapia , Copper , Marine toxins , Fishes -- Effect of water pollution on , Water -- Pollution -- Environmental aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5234 , http://hdl.handle.net/10962/d1005077 , Mozambique tilapia , Copper , Marine toxins , Fishes -- Effect of water pollution on , Water -- Pollution -- Environmental aspects
- Description: Cu is one of the most toxic elements that affect fish populations when the fish are exposed to concentrations exceeding their tolerance. To investigate the effects of elementary Cu on aspects of bioconcentration, histology and behaviour, O. mossambicus were exposed to 0 and 0.75 ± 0.20 mg/l of Cu for 96 hours (short-term study), and 0, 0.11 ± 0.02, 0.29 ± 0.02, and 0.47 ± 0.04 mg/l of Cu for 64 days (longterm study) under controlled conditions in the laboratory. For the long-term study fish were sampled for gills, liver, and kidney Cu accumulation analysis after 1, 32 and 64 days of exposure and after 1, 2, 4, 16, 32, and 64 days for gills, liver and spleen histology analysis. Cu accumulation was concentration-duration dependent with the highest accumulation capacity in the liver. A multifactor linear model was developed for the relationship between exposure dose, exposure duration and Cu accumulation in the organs with the liver model: Log L = 3.35 + 0.85W + 0.31T (r² = 0.892) giving a better fit than the gills: G = −35.09 + 10.58W + 17.58T (r² = 0.632). Where L = Cu accumulation values in the liver, G = Cu accumulation values in the gills (both in μg/g dry mass); W = exposure dose in water (mg/l); and T = exposure time (days). Using this model Cu accumulation in organs can be estimated when exposure concentration and duration is known. This model should be tested under different conditions to determine the potential of the model in monitoring Cu toxicity in the environment. Lesions were observed in the liver, gills and spleen in all Cu treatments at all exposure concentration and exposure durations. However, the incidence and the degree of alteration was related to the concentration of Cu and duration of exposure. The sequential appearance of lesions in the order of, hepatic vacuolar degeneration, fatty degeneration and necrosis indicated a gradual increase in liver damage with larger duration of exposure time and increasing Cu concentration. The initial lesions in the gills were manifested as hypertrophy and hyperplasia of the gill epithelium causing increase in the thickness of the secondary lamellae, mucous cell hypertrophy and proliferation, mucous hypersecretion, proliferation of eosinophilic granule cells and hyperplasia of interlamellar cells. With increase in exposure time, necrosis of the eosinophilic granule cells, lamellar oedema, epithelial desquamation and increase in severity of lamellar hyperplasia were observed. These lesions indicated an initial defence mechanism of the fish against Cu toxicity followed by advanced histological changes that were related to Cu concentration and duration of exposure. Changes in the spleen were haemosiderosis, increase in the white pulp and macrophage centres, reduction in the red pulp, and necrosis suggesting that fish exposed to environmentally relevant levels of Cu may be histopathologically altered leading to anaemia and immunosuppression. Regression analysis was used to quantify the relationship between the total activity of the fish, and duration of exposure. There was a gradual decline in fish activity related to Cu concentration and duration of exposure before introducing food into the tanks. There was a constant activity after introducing food in the tanks at the control and 0.11 ± 0.02 mg/l Cu exposure levels irrespective of exposure time. Analysis of covariance (ANCOVA) was used to test for the difference in slopes between treatments. There was no significant difference (p > 0.05) between slopes of the control and 0.11 ± 0.02 mg/l Cu, and between 0.29 ± 0.02 and 47 ± 0.04 mg/l Cu before and after introducing food in the tanks. The slopes of both the control and 0.11 ± 0.02 mg/l Cu were significantly different from those of 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu (p < 0.05). There were significant differences in the mean opercular movements per minute between treatments (p < 0.05). There was hyperventilation at 0.11 ± 0.02 mg/l Cu i.e. 87 ± 18 opercular movements per minute (mean ± standard deviation) and hypoventilation at 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu i.e. 37 ± 34 and 13 ± 6 opercular movements per minute compared to the control. Hypo- and hyperventilation were related to the lesser and greater gill damage, respectively. In conclusion Cu accumulation and effects on histology of the liver, gills and were related to the concentration of Cu in the water and duration of exposure showing a gradual increase in incidence and intensity with larger duration of exposure time and increasing Cu concentration. The fish were initially able to homeostatically regulate and detoxify Cu. However, as the exposure continued, the homeostatic mechanism appears to have failed to cope with the increasing metal burden causing advanced histological changes.
- Full Text:
- Date Issued: 2003
PyMORESANE: A Pythonic and CUDA-accelerated implementation of the MORESANE deconvolution algorithm
- Authors: Kenyon, Jonathan
- Date: 2015
- Subjects: Radio astronomy , Imaging systems in astronomy , MOdel REconstruction by Synthesis-ANalysis Estimators (MORESANE)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5563 , http://hdl.handle.net/10962/d1020098
- Description: The inadequacies of the current generation of deconvolution algorithms are rapidly becoming apparent as new, more sensitive radio interferometers are constructed. In light of these inadequacies, there is renewed interest in the field of deconvolution. Many new algorithms are being developed using the mathematical framework of compressed sensing. One such technique, MORESANE, has recently been shown to be a powerful tool for the recovery of faint difuse emission from synthetic and simulated data. However, the original implementation is not well-suited to large problem sizes due to its computational complexity. Additionally, its use of proprietary software prevents it from being freely distributed and used. This has motivated the development of a freely available Python implementation, PyMORESANE. This thesis describes the implementation of PyMORESANE as well as its subsequent augmentation with MPU and GPGPU code. These additions accelerate the algorithm and thus make it competitive with its legacy counterparts. The acceleration of the algorithm is verified by means of benchmarking tests for varying image size and complexity. Additionally, PyMORESANE is shown to work not only on synthetic data, but on real observational data. This verification means that the MORESANE algorithm, and consequently the PyMORESANE implementation, can be added to the current arsenal of deconvolution tools.
- Full Text:
- Date Issued: 2015
- Authors: Kenyon, Jonathan
- Date: 2015
- Subjects: Radio astronomy , Imaging systems in astronomy , MOdel REconstruction by Synthesis-ANalysis Estimators (MORESANE)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5563 , http://hdl.handle.net/10962/d1020098
- Description: The inadequacies of the current generation of deconvolution algorithms are rapidly becoming apparent as new, more sensitive radio interferometers are constructed. In light of these inadequacies, there is renewed interest in the field of deconvolution. Many new algorithms are being developed using the mathematical framework of compressed sensing. One such technique, MORESANE, has recently been shown to be a powerful tool for the recovery of faint difuse emission from synthetic and simulated data. However, the original implementation is not well-suited to large problem sizes due to its computational complexity. Additionally, its use of proprietary software prevents it from being freely distributed and used. This has motivated the development of a freely available Python implementation, PyMORESANE. This thesis describes the implementation of PyMORESANE as well as its subsequent augmentation with MPU and GPGPU code. These additions accelerate the algorithm and thus make it competitive with its legacy counterparts. The acceleration of the algorithm is verified by means of benchmarking tests for varying image size and complexity. Additionally, PyMORESANE is shown to work not only on synthetic data, but on real observational data. This verification means that the MORESANE algorithm, and consequently the PyMORESANE implementation, can be added to the current arsenal of deconvolution tools.
- Full Text:
- Date Issued: 2015
Development and optimisation of a novel Plasmodium falciparum Hsp90-Hop interaction assay
- Authors: Wambua, Lynn
- Date: 2018
- Subjects: Plasmodium falciparum , Molecular chaperones , Heat shock proteins , Protein-protein interactions , Antimalarials
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62626 , vital:28216
- Description: Protein-protein interactions are involved in a range of disease processes and thus have become the focus of many drug discovery programs. Widespread drug resistance to all currently used antimalarial drugs drives the search for alternative drug targets with novel mechanisms of action that offer new therapeutic options. Molecular chaperones such as heat shock proteins facilitate protein folding, play a role in protein trafficking and prevent protein misfolding in cells under stress. Heat shock protein 90 (Hsp90) is a well-studied chaperone that has been the focus of cancer drug development with moderate success. In Plasmodium falciparum (P. falciparum), heat shock proteins are thought to play a vital role in parasite survival of the physiologically diverse habitats of the parasite lifecycle and because Hsp90 is prominently expressed in P. falciparum, the chaperone is considered a potentially ideal drug target. Hsp90 function in cells is regulated by interactions with co-chaperones, which includes Heat shock protein 70-Heat shock protein 90 organising protein (Hop). As opposed to directly inhibiting Hsp90 activity, targeting Hsp90 interaction with Hop has recently been suggested as an alternative method of Hsp90 inhibition that has not been explored in P. falciparum. The aim of this research project was to demonstrate PfHsp90 and PfHop robustly interact in vitro and to facilitate high-throughput screening of PfHsp90-PfHop inhibitors by developing and optimising a novel plate capture Hsp90-Hop interaction assay. To establish the assay, the respective domains of the proteins that mediate Hsp90-Hop interaction were used (Hsp90 C- terminal domain and Hop TPR2A domain). The human Hsp90 C-terminal domain and glutathione-S-transferase (GST) coding sequences were cloned into pET-28a(+) and murine and P. falciparum TPR2A sequences into pGEX-4T-1 plasmids to enable expression of histidine-tagged and GST fusion proteins, respectively, in Escherichia coli. The P. falciparum Hsp90 C-terminal domain sequence cloned into pET-28a(+) was supplied by GenScript. The constructs were transformed into T7 Express lysYcompetent E. coli cells and subsequent small- scale expression studies showed the recombinant proteins were expressed in a soluble form allowing for subsequent protein purification. Purification of the recombinant proteins was achieved using nickel-NTA and glutathione affinity chromatography for the His-tagged (Hsp90 C-terminal domains and GST) and GST fusion proteins (TPR2A domains), respectively. The purified proteins were used to establish and optimise mammalian and P. falciparum Hsp90- Hop interaction assays on nickel-coated plates by immobilising the His-tagged C-terminal domains on the plates and detecting the binding of the GST-TPR2A domains using a colorimetric GST enzyme assay. Z’-factor values above 0.5 were observed for both assays indicating good separation between the protein interaction signals and negative control background signals, although relatively high background signals were observed for the mammalian interaction due to non-specific binding of murine TPR2A to the plate. Designed human and P. falciparum TPR peptides were observed to be effective inhibitors of the mammalian and P. falciparum interactions, demonstrating the assay’s ability to respond to inhibitor compounds. Comparison of assay performance using GST assay kit reagents and lab- prepared reagents showed the assay was more efficient using lab-prepared reagents, however, lower GST signals were observed when comparing assay performance using a custom prepared Ni-NTA plate to a purchased Ni-NTA plate. The Hsp90-Hop interaction assays were also performed using an alternative assay format in which the GST-TPR2A fusion proteins were immobilised on glutathione-coated plates and binding of the His-tagged C-terminal domains detected with a nickel-horseradish peroxidase (HRP) conjugate and a colorimetric HRP substrate. The assay showed higher interaction signals for the P. falciparum proteins but comparatively low signals for the mammalian proteins. Z’-factor values for the assay were above 0.8 for both protein sets, suggesting this assay format is superior to the GST assay. However, further optimisation of this assay format is required. This study demonstrated direct binding of PfHsp90-PfHop in vitro and established a novel and robust PfHsp90-PfHop interaction assay format that can be used in future screening campaigns.
- Full Text:
- Date Issued: 2018
- Authors: Wambua, Lynn
- Date: 2018
- Subjects: Plasmodium falciparum , Molecular chaperones , Heat shock proteins , Protein-protein interactions , Antimalarials
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62626 , vital:28216
- Description: Protein-protein interactions are involved in a range of disease processes and thus have become the focus of many drug discovery programs. Widespread drug resistance to all currently used antimalarial drugs drives the search for alternative drug targets with novel mechanisms of action that offer new therapeutic options. Molecular chaperones such as heat shock proteins facilitate protein folding, play a role in protein trafficking and prevent protein misfolding in cells under stress. Heat shock protein 90 (Hsp90) is a well-studied chaperone that has been the focus of cancer drug development with moderate success. In Plasmodium falciparum (P. falciparum), heat shock proteins are thought to play a vital role in parasite survival of the physiologically diverse habitats of the parasite lifecycle and because Hsp90 is prominently expressed in P. falciparum, the chaperone is considered a potentially ideal drug target. Hsp90 function in cells is regulated by interactions with co-chaperones, which includes Heat shock protein 70-Heat shock protein 90 organising protein (Hop). As opposed to directly inhibiting Hsp90 activity, targeting Hsp90 interaction with Hop has recently been suggested as an alternative method of Hsp90 inhibition that has not been explored in P. falciparum. The aim of this research project was to demonstrate PfHsp90 and PfHop robustly interact in vitro and to facilitate high-throughput screening of PfHsp90-PfHop inhibitors by developing and optimising a novel plate capture Hsp90-Hop interaction assay. To establish the assay, the respective domains of the proteins that mediate Hsp90-Hop interaction were used (Hsp90 C- terminal domain and Hop TPR2A domain). The human Hsp90 C-terminal domain and glutathione-S-transferase (GST) coding sequences were cloned into pET-28a(+) and murine and P. falciparum TPR2A sequences into pGEX-4T-1 plasmids to enable expression of histidine-tagged and GST fusion proteins, respectively, in Escherichia coli. The P. falciparum Hsp90 C-terminal domain sequence cloned into pET-28a(+) was supplied by GenScript. The constructs were transformed into T7 Express lysYcompetent E. coli cells and subsequent small- scale expression studies showed the recombinant proteins were expressed in a soluble form allowing for subsequent protein purification. Purification of the recombinant proteins was achieved using nickel-NTA and glutathione affinity chromatography for the His-tagged (Hsp90 C-terminal domains and GST) and GST fusion proteins (TPR2A domains), respectively. The purified proteins were used to establish and optimise mammalian and P. falciparum Hsp90- Hop interaction assays on nickel-coated plates by immobilising the His-tagged C-terminal domains on the plates and detecting the binding of the GST-TPR2A domains using a colorimetric GST enzyme assay. Z’-factor values above 0.5 were observed for both assays indicating good separation between the protein interaction signals and negative control background signals, although relatively high background signals were observed for the mammalian interaction due to non-specific binding of murine TPR2A to the plate. Designed human and P. falciparum TPR peptides were observed to be effective inhibitors of the mammalian and P. falciparum interactions, demonstrating the assay’s ability to respond to inhibitor compounds. Comparison of assay performance using GST assay kit reagents and lab- prepared reagents showed the assay was more efficient using lab-prepared reagents, however, lower GST signals were observed when comparing assay performance using a custom prepared Ni-NTA plate to a purchased Ni-NTA plate. The Hsp90-Hop interaction assays were also performed using an alternative assay format in which the GST-TPR2A fusion proteins were immobilised on glutathione-coated plates and binding of the His-tagged C-terminal domains detected with a nickel-horseradish peroxidase (HRP) conjugate and a colorimetric HRP substrate. The assay showed higher interaction signals for the P. falciparum proteins but comparatively low signals for the mammalian proteins. Z’-factor values for the assay were above 0.8 for both protein sets, suggesting this assay format is superior to the GST assay. However, further optimisation of this assay format is required. This study demonstrated direct binding of PfHsp90-PfHop in vitro and established a novel and robust PfHsp90-PfHop interaction assay format that can be used in future screening campaigns.
- Full Text:
- Date Issued: 2018
Opening 28th Annual General Meeting of SA Pharmacy Students Federation
- Authors: Henderson, Derek Scott
- Date: 1981-06-30
- Language: English
- Type: Text
- Identifier: vital:7433 , http://hdl.handle.net/10962/d1018310
- Full Text:
- Date Issued: 1981-06-30
- Authors: Henderson, Derek Scott
- Date: 1981-06-30
- Language: English
- Type: Text
- Identifier: vital:7433 , http://hdl.handle.net/10962/d1018310
- Full Text:
- Date Issued: 1981-06-30
Photophysicochemical and photodynamic studies of phthalocyanines conjugated to selected drug delivery agents
- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
- Full Text:
- Date Issued: 2012
- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
- Full Text:
- Date Issued: 2012
Epithermal precious metal deposits physicochemical constraints, classification characteristics and exploration guidelines
- Authors: McIver, Donald A
- Date: 1997
- Subjects: Precious metals , Geothermal resources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4941 , http://hdl.handle.net/10962/d1005553 , Precious metals , Geothermal resources
- Description: Epithermal deposits include a broad range of precious metal, base metal, mercury, and stibnite deposits. These deposits exhibit a low temperature of formation (180-280°C) at pressures of less than a few hundred bars (equivalent to depths of 1.5 - 2.0lkm). Epithermal gold deposits are the product of large-scale hydrothermal systems which mostly occur in convergent plate margin settings. Associated volcanism is largely of andesitic arc (calcalkaline to alkaline), or rhyolitic back-arc type. Porphyry Cu-Mo-Au deposits form deeper in the same systems. Genetic processes within individual deposits take place in an extremely complex manner. The resultant mineral associations, alteration styles and metal deposition patterns are even more complicated. Many attempts have been made to classify epithermal deposits based on mineralogy and alteration, host rocks, deposit form, genetic models, and standard deposits. For the explorationist, the most useful classification schemes should be brief, simple, descriptive, observationally based, and informative. Ultimately, two distinct styles of epithermal gold deposits are readily recognised: high-sulphidation, acid sulphate and low-sulphidation, adularia-sericite types. The terms high-sulphidation (HS) and low-sulphidation (IS) are based on the sulphidation state of associated sulphide minerals, which, along with characteristic hydrothermal alteration, reflect fundamental chemical differences in the epithermal environment. Highsulphidation-type deposits form in the root zones of volcanic domes from acid waters that contain residual magmatic volatiles. The low-sulphidation-type deposits form in geothermal systems where surficial waters mix with deeper, heated saline waters in a lateral flow regime, where neutral to weakly acidic, alkali chloride waters are dominant. The HSILS classification, combined with a simple description of the form of the deposit, conveys a large amount of information on mineralogy, alteration, and spatial characteristics of the mineralisation, and allows inferences to be drawn regarding likely regional controls, and the characteristics of the ore-forming fluids. The modern understanding of these environments allows us to quite effectively identify the most probable foci of mineral deposition in any given district. Current knowledge of these deposits has been derived from studies of active geothermal systems. Through comparison with alteration zones within these systems, the exploration geologist may determine the potential distribution and types of ore in a fossil geothermal system. Alteration zoning specifically can be used as a guide towards the most prospective part of the system. Epithermal gold deposits of both HS- and LS-styles are nevertheless profoundly difficult exploration targets. Successful exploration must rely on the integration of a variety of exploration techniques, guided by an understanding of the characteristics of the deposits and the processes that form them. There are no simple formulae for success in epithermal exploration: what works best must be determined for each terrain and each prospect. On a regional scale tectonic, igneous and structural settings can be used, together with assessment of the depth of erosion, to select areas for project area scale exploration. Integrated geological-geophysical interpretation derived from airborne geophysics providesa basis of targeting potential ore environments for follow-up. Geology, geochemistry and surface geophysics localise mineral concentrations within these target areas
- Full Text:
- Date Issued: 1997
- Authors: McIver, Donald A
- Date: 1997
- Subjects: Precious metals , Geothermal resources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4941 , http://hdl.handle.net/10962/d1005553 , Precious metals , Geothermal resources
- Description: Epithermal deposits include a broad range of precious metal, base metal, mercury, and stibnite deposits. These deposits exhibit a low temperature of formation (180-280°C) at pressures of less than a few hundred bars (equivalent to depths of 1.5 - 2.0lkm). Epithermal gold deposits are the product of large-scale hydrothermal systems which mostly occur in convergent plate margin settings. Associated volcanism is largely of andesitic arc (calcalkaline to alkaline), or rhyolitic back-arc type. Porphyry Cu-Mo-Au deposits form deeper in the same systems. Genetic processes within individual deposits take place in an extremely complex manner. The resultant mineral associations, alteration styles and metal deposition patterns are even more complicated. Many attempts have been made to classify epithermal deposits based on mineralogy and alteration, host rocks, deposit form, genetic models, and standard deposits. For the explorationist, the most useful classification schemes should be brief, simple, descriptive, observationally based, and informative. Ultimately, two distinct styles of epithermal gold deposits are readily recognised: high-sulphidation, acid sulphate and low-sulphidation, adularia-sericite types. The terms high-sulphidation (HS) and low-sulphidation (IS) are based on the sulphidation state of associated sulphide minerals, which, along with characteristic hydrothermal alteration, reflect fundamental chemical differences in the epithermal environment. Highsulphidation-type deposits form in the root zones of volcanic domes from acid waters that contain residual magmatic volatiles. The low-sulphidation-type deposits form in geothermal systems where surficial waters mix with deeper, heated saline waters in a lateral flow regime, where neutral to weakly acidic, alkali chloride waters are dominant. The HSILS classification, combined with a simple description of the form of the deposit, conveys a large amount of information on mineralogy, alteration, and spatial characteristics of the mineralisation, and allows inferences to be drawn regarding likely regional controls, and the characteristics of the ore-forming fluids. The modern understanding of these environments allows us to quite effectively identify the most probable foci of mineral deposition in any given district. Current knowledge of these deposits has been derived from studies of active geothermal systems. Through comparison with alteration zones within these systems, the exploration geologist may determine the potential distribution and types of ore in a fossil geothermal system. Alteration zoning specifically can be used as a guide towards the most prospective part of the system. Epithermal gold deposits of both HS- and LS-styles are nevertheless profoundly difficult exploration targets. Successful exploration must rely on the integration of a variety of exploration techniques, guided by an understanding of the characteristics of the deposits and the processes that form them. There are no simple formulae for success in epithermal exploration: what works best must be determined for each terrain and each prospect. On a regional scale tectonic, igneous and structural settings can be used, together with assessment of the depth of erosion, to select areas for project area scale exploration. Integrated geological-geophysical interpretation derived from airborne geophysics providesa basis of targeting potential ore environments for follow-up. Geology, geochemistry and surface geophysics localise mineral concentrations within these target areas
- Full Text:
- Date Issued: 1997
Address to Convocation, 2 April 1977
- Authors: Henderson, Derek Scott
- Subjects: Rhodes University -- Convocation
- Language: English
- Type: Text
- Identifier: vital:7350 , http://hdl.handle.net/10962/d1017079
- Full Text:
- Authors: Henderson, Derek Scott
- Subjects: Rhodes University -- Convocation
- Language: English
- Type: Text
- Identifier: vital:7350 , http://hdl.handle.net/10962/d1017079
- Full Text:
An investigation into the role of student participation in school governance : a Namibian perspective
- Authors: Shekupakela-Nelulu, Rauna
- Date: 2009
- Subjects: Education and state -- Namibia Education, Secondary -- Namibia Student government -- Namibia Student participation in administration -- Namibia School management and organization -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1923 , http://hdl.handle.net/10962/d1007449
- Description: The issue of student participation in school governance is not a new concept in Namibian schools. Student involvement dates back to the 1970's when the country's administration was under the South African apartheid regime. Back then the involvement of students in school affairs was seen by the regime as a political act and attempts by student leaders to involve themselves in educational issues were often quashed. When the country became independent student representation continued as Student Representative Councils (SRC's), later renamed Learners Representative Councils (LRCs). This study attempted to investigate the perceptions of LRCs and other stakeholders - narnely the school principals and the school board members - of the role of students in school governance. The study was conducted in three Senior Secondary Schools in the Kavango region in Namibia. The research respondents were school principals, chairpersons of the LRCs and one chairperson of a school board. The study was conducted in the interpretive paradigm employing the following three qualitative research methods interviews, observation and document analysis to collect data. Through triangulation it was possible to formulate a rich response to the research question. The study found that, although the notion of student participation in school governance was widely accepted, a number of challenges exist that hamper the effectiveness of LRCs in the schools. It was revealed that there was no national policy docunlent that outlined the roles and function of the LRCs. As a result schools had little direction about the LRCs and subsequently they were given little or no attention by the school authorities. This resulted in misunderstandings and in some cases conflict between learners and the school management. The most significant consequence of these problems was the fact that LRCs were not regarded as true role players in school governance. The study thus recommends that a national policy document that legitimates the role of students in school governance be drafted to provide direction and that schools embark on meaningful training programmes for LRC members. The study also calls for further research to address the gap in literature on this phenomenon, particularly in Namibia.
- Full Text:
- Date Issued: 2009
- Authors: Shekupakela-Nelulu, Rauna
- Date: 2009
- Subjects: Education and state -- Namibia Education, Secondary -- Namibia Student government -- Namibia Student participation in administration -- Namibia School management and organization -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1923 , http://hdl.handle.net/10962/d1007449
- Description: The issue of student participation in school governance is not a new concept in Namibian schools. Student involvement dates back to the 1970's when the country's administration was under the South African apartheid regime. Back then the involvement of students in school affairs was seen by the regime as a political act and attempts by student leaders to involve themselves in educational issues were often quashed. When the country became independent student representation continued as Student Representative Councils (SRC's), later renamed Learners Representative Councils (LRCs). This study attempted to investigate the perceptions of LRCs and other stakeholders - narnely the school principals and the school board members - of the role of students in school governance. The study was conducted in three Senior Secondary Schools in the Kavango region in Namibia. The research respondents were school principals, chairpersons of the LRCs and one chairperson of a school board. The study was conducted in the interpretive paradigm employing the following three qualitative research methods interviews, observation and document analysis to collect data. Through triangulation it was possible to formulate a rich response to the research question. The study found that, although the notion of student participation in school governance was widely accepted, a number of challenges exist that hamper the effectiveness of LRCs in the schools. It was revealed that there was no national policy docunlent that outlined the roles and function of the LRCs. As a result schools had little direction about the LRCs and subsequently they were given little or no attention by the school authorities. This resulted in misunderstandings and in some cases conflict between learners and the school management. The most significant consequence of these problems was the fact that LRCs were not regarded as true role players in school governance. The study thus recommends that a national policy document that legitimates the role of students in school governance be drafted to provide direction and that schools embark on meaningful training programmes for LRC members. The study also calls for further research to address the gap in literature on this phenomenon, particularly in Namibia.
- Full Text:
- Date Issued: 2009
The effectiveness of networking and collaboration in creative hubs: a case of Hub@Goethe
- Authors: De Beer, Magdalena Gertruda
- Date: 2022-04-06
- Subjects: Cultural industries South Africa , Cultural industries Economic aspects South Africa , Economic development projects South Africa , Social entrepreneurship South Africa , Creative ability Economic aspects South Africa , Social capital (Sociology) South Africa , Social networks South Africa , Hub@Goethe
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284504 , vital:56069
- Description: This research took the form of a case study investigating the effectiveness of a single hub in South Africa, namely Hub@Goethe in Johannesburg. The context of the creative economy and creative industries provided insight into the experiences of creative cultural labourers in the new economic model. The context emphasised the research problem which considered the difficulties experienced by creative and cultural entrepreneurs and their career paths who, through labour precarity, remain isolated from the market, without access to physical spaces, network connections and business knowledge to realise their business ideas. The literature reviewed revealed how co-working office spaces, creative spaces and hubs provide creative entrepreneurs with the spatial infrastructure, amenities, and network access to mitigate challenges in the creative cultural sectors. These spaces offer a multitude of different amenities which is specific to their community’s needs. Guided by the theory of social capital and structural holes reviewed in the literature, the effectiveness was assessed by the hub’s ability to provide network access benefits or resource endowments. The research looked at whether the hub could provide creative cultural entrepreneurs with resource benefits such as a) access to social interactions, collaboration, and knowledge sharing, b) access to business or professional skills-based education programmes and mentorship, c) access to market and d) generation both social and economic benefit. The research adopted a qualitative approach, seeking insights into the creative entrepreneurs’ experiences at the hub utilising one-to-one interviews. The thematic analysis confirmed that the hub was effective overall in providing entrepreneurs with access to benefits or resource endowments embedded in the network, confirming that hubs may be an effective tool in mitigating difficulties experienced by creative entrepreneurs in the creative industries. The research also showed areas of improvement where the hub could increase its experienced effectiveness, especially in reference to routes to market. The research findings inferred the importance of physical space, proximity and accessibility has on collaborative practices amongst creative entrepreneurs within the hub space. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: De Beer, Magdalena Gertruda
- Date: 2022-04-06
- Subjects: Cultural industries South Africa , Cultural industries Economic aspects South Africa , Economic development projects South Africa , Social entrepreneurship South Africa , Creative ability Economic aspects South Africa , Social capital (Sociology) South Africa , Social networks South Africa , Hub@Goethe
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284504 , vital:56069
- Description: This research took the form of a case study investigating the effectiveness of a single hub in South Africa, namely Hub@Goethe in Johannesburg. The context of the creative economy and creative industries provided insight into the experiences of creative cultural labourers in the new economic model. The context emphasised the research problem which considered the difficulties experienced by creative and cultural entrepreneurs and their career paths who, through labour precarity, remain isolated from the market, without access to physical spaces, network connections and business knowledge to realise their business ideas. The literature reviewed revealed how co-working office spaces, creative spaces and hubs provide creative entrepreneurs with the spatial infrastructure, amenities, and network access to mitigate challenges in the creative cultural sectors. These spaces offer a multitude of different amenities which is specific to their community’s needs. Guided by the theory of social capital and structural holes reviewed in the literature, the effectiveness was assessed by the hub’s ability to provide network access benefits or resource endowments. The research looked at whether the hub could provide creative cultural entrepreneurs with resource benefits such as a) access to social interactions, collaboration, and knowledge sharing, b) access to business or professional skills-based education programmes and mentorship, c) access to market and d) generation both social and economic benefit. The research adopted a qualitative approach, seeking insights into the creative entrepreneurs’ experiences at the hub utilising one-to-one interviews. The thematic analysis confirmed that the hub was effective overall in providing entrepreneurs with access to benefits or resource endowments embedded in the network, confirming that hubs may be an effective tool in mitigating difficulties experienced by creative entrepreneurs in the creative industries. The research also showed areas of improvement where the hub could increase its experienced effectiveness, especially in reference to routes to market. The research findings inferred the importance of physical space, proximity and accessibility has on collaborative practices amongst creative entrepreneurs within the hub space. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
Rhodeo: 1946
- Date: 1946
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14429 , http://hdl.handle.net/10962/d1019301
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1946
- Date: 1946
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14429 , http://hdl.handle.net/10962/d1019301
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1946
Vocabulary development in a grade 7 class using dictionary skills: an action research project
- Authors: Wells, Stephanie Alice
- Date: 2011
- Subjects: English language -- Study and teaching (Elementary) -- South Africa -- Eastern Cape Vocabulary -- Study and teaching (Elementary) -- South Africa -- Eastern Cape English language Dictionaries -- Polyglot -- Study and teaching (Elementary) -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1822 , http://hdl.handle.net/10962/d1003708
- Description: As I was involved as a voluntary, part-time teacher in a local, semi-rural school in the Eastern Cape, South Africa, I became increasingly aware of the learners' lack of English literacy. I therefore decided to do a practical research on vocabulary development, focusing on dictionary skills. In this thesis I describe how I implemented a vocabulary development programme as an Action Research project. My research group was a grade 7 class of English First Additional Language learners who had minimal exposure to English at school and in their communities. The class was a mixture of Afrikaans and isiXhosa home language speakers and the medium of instruction was Afrikaans. The school served a low-income community and was poorly resourced. As dictionary skills is a requirement of the national curriculum, I used 10 time-tabled lessons over a 5 week period to introduce the learners to dictionaries. My data sources were a journal detailing my reflections on each lesson; a video-recording of the lessons; small group interviews after each lesson which were audio-recorded; tasksheets on the work covered in class and questionnaires asking the learners for written responses to the lessons. The class teacher who filmed the lessons was also asked for feedback during and after the programme. My goals were to assess my teaching approach in these circumstances and to what extent the outcomes were positive for the learners. As I had come from a background of English Home Language teaching in good, well-resourced schools I found I had to question many of my assumptions. Although I was an experienced, qualified and confident teacher, I was continually having to reassess my teaching methods which were being challenged by very different classroom conditions. The outcomes of the research show why I was not able to achieve what I had thought I could in the time given.
- Full Text:
- Date Issued: 2011
- Authors: Wells, Stephanie Alice
- Date: 2011
- Subjects: English language -- Study and teaching (Elementary) -- South Africa -- Eastern Cape Vocabulary -- Study and teaching (Elementary) -- South Africa -- Eastern Cape English language Dictionaries -- Polyglot -- Study and teaching (Elementary) -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1822 , http://hdl.handle.net/10962/d1003708
- Description: As I was involved as a voluntary, part-time teacher in a local, semi-rural school in the Eastern Cape, South Africa, I became increasingly aware of the learners' lack of English literacy. I therefore decided to do a practical research on vocabulary development, focusing on dictionary skills. In this thesis I describe how I implemented a vocabulary development programme as an Action Research project. My research group was a grade 7 class of English First Additional Language learners who had minimal exposure to English at school and in their communities. The class was a mixture of Afrikaans and isiXhosa home language speakers and the medium of instruction was Afrikaans. The school served a low-income community and was poorly resourced. As dictionary skills is a requirement of the national curriculum, I used 10 time-tabled lessons over a 5 week period to introduce the learners to dictionaries. My data sources were a journal detailing my reflections on each lesson; a video-recording of the lessons; small group interviews after each lesson which were audio-recorded; tasksheets on the work covered in class and questionnaires asking the learners for written responses to the lessons. The class teacher who filmed the lessons was also asked for feedback during and after the programme. My goals were to assess my teaching approach in these circumstances and to what extent the outcomes were positive for the learners. As I had come from a background of English Home Language teaching in good, well-resourced schools I found I had to question many of my assumptions. Although I was an experienced, qualified and confident teacher, I was continually having to reassess my teaching methods which were being challenged by very different classroom conditions. The outcomes of the research show why I was not able to achieve what I had thought I could in the time given.
- Full Text:
- Date Issued: 2011
Family planning : an evaluative study on the attitudes and use of contraceptives by black males in Umtata
- Authors: Madikizela, Nosinodi Alicia
- Date: 1989
- Subjects: Birth control -- South Africa -- Transkei , Transkei (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3278 , http://hdl.handle.net/10962/d1006454 , Birth control -- South Africa -- Transkei , Transkei (South Africa) -- Social conditions
- Description: The purpose of this study is to identify, observe and record the attitudes and use to of contraceptives by black males in Umtata and to investigate the effect of education, urbanisation and age on fertility control. Data was gathered from a sample of adult males who were past the school going age and were employed or working in Umtata and its surburbs, which are Ngangelizwe, Ikwezi, Southernwood, Northcrest, Norwood, Ncambedlana, Nduli Crescent, Fortgale and Hill Crest. Information was also gathered from Nursing officers in charge of family planning service centres in the areas mentioned above. Findings reveal that, although black urbanised educated males in Umtata seem to have accepted the use of contraceptives by themselves and their sexual partners, their patterns of behaviour in relation to fertility control and the value of children to families remains traditional. This contributes to the relatively high fertility rate in the country. Children are an investment for old age. They are also regarded as a security factor against divorce. It is the duty of legally married couples to raise a family with children who will continue to bear the family name. It appears that men are either suspicious of modern contraception if not totally opposed to it. Many still prefer the use of natural methods of contraception. There is thus need for social workers and health planners to recognise and educate males on the use and benefits of modern contraceptives to limit the number of children borne and control periods when they would like to have children. This study will be of value to social welfare services and to family planning nurses who are in direct contact with clients in hospitals and clinics, in their family planning campaigns, when they motivate couples and individuals on the importance of family planning, and also in mother-and-child health services. Educationists, sociologists, psychologists and persons in other fields of study will also benefit from information attained in this survey.
- Full Text:
- Date Issued: 1989
- Authors: Madikizela, Nosinodi Alicia
- Date: 1989
- Subjects: Birth control -- South Africa -- Transkei , Transkei (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3278 , http://hdl.handle.net/10962/d1006454 , Birth control -- South Africa -- Transkei , Transkei (South Africa) -- Social conditions
- Description: The purpose of this study is to identify, observe and record the attitudes and use to of contraceptives by black males in Umtata and to investigate the effect of education, urbanisation and age on fertility control. Data was gathered from a sample of adult males who were past the school going age and were employed or working in Umtata and its surburbs, which are Ngangelizwe, Ikwezi, Southernwood, Northcrest, Norwood, Ncambedlana, Nduli Crescent, Fortgale and Hill Crest. Information was also gathered from Nursing officers in charge of family planning service centres in the areas mentioned above. Findings reveal that, although black urbanised educated males in Umtata seem to have accepted the use of contraceptives by themselves and their sexual partners, their patterns of behaviour in relation to fertility control and the value of children to families remains traditional. This contributes to the relatively high fertility rate in the country. Children are an investment for old age. They are also regarded as a security factor against divorce. It is the duty of legally married couples to raise a family with children who will continue to bear the family name. It appears that men are either suspicious of modern contraception if not totally opposed to it. Many still prefer the use of natural methods of contraception. There is thus need for social workers and health planners to recognise and educate males on the use and benefits of modern contraceptives to limit the number of children borne and control periods when they would like to have children. This study will be of value to social welfare services and to family planning nurses who are in direct contact with clients in hospitals and clinics, in their family planning campaigns, when they motivate couples and individuals on the importance of family planning, and also in mother-and-child health services. Educationists, sociologists, psychologists and persons in other fields of study will also benefit from information attained in this survey.
- Full Text:
- Date Issued: 1989
A standardised protocol for roadkill detection and the determinants of roadkill in the greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa
- Authors: Collinson, Wendy Jane
- Date: 2013
- Subjects: Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5606 , http://hdl.handle.net/10962/d1002056 , Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Description: Despite evidence suggesting that road traffic is a major threat to biodiversity loss, very little is known about its actual impact on wildlife populations in South Africa. Globally, road density and traffic volumes are increasing, and although huge budgets are devoted to the construction and upgrading of roads, there is little or no allocation to mitigation measures for protecting fauna in most countries, particularly Africa. Further, no global standardised protocol exists for the rapid assessment of roadkill or the most economical and efficient approach for assessing roadkill rates. Using vehicle field trials, the reliability of detecting artificially deployed roadkill was assessed. Roadkill detection rates decreased significantly at speeds >50 km/h and were also significantly influenced by light conditions (i.e. detection success was greater when the sun was high) and the position of the roadkill on the road (i.e. smaller roadkill on verges were often missed). These results suggest that roadkill sampling was most effective between 1.5 hours after dawn and 1.5 hours before dusk and that driving at slower speeds (<50 km.h⁻ₑ) was required to detect roadkill. This protocol was implemented across three ecological seasons on a 100 km paved road and a 20 km unpaved road in the Greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa. Driven daily over a 120-day period (three periods consisting each of 40 days), a total of 1,027 roadkill were recorded. These comprised 162 species from all terrestrial vertebrate groups with birds being the most commonly encountered roadkill (50% of all incidents). The high numbers of vertebrates identified as roadkill suggests that road traffic could have potentially unsustainable impacts on wildlife populations and hence the biodiversity of the area. Seventeen variables were identified as possible determinants of roadkill occurrence with season, rainfall, minimum and maximum temperature, habitat type, grass height, grass density, fence type and vehicle type significantly influencing roadkill numbers. Significantly more roadkill were detected on the paved road (9.91/100km) than on the unpaved road (1.8/100km) probably because of greater traffic volumes and the increased speed that vehicles travelled on the paved road. Warmer temperatures and increased rainfall in the preceding 24 hours also increased road mortality numbers as animals tended to become more active during these times. Interestingly, more roadkill was detected in open roadside habitats compared to dense roadside habitats on both the paved and unpaved roads and when grass on the roadside verge was of intermediate height. Open habitat possibly may provide a natural corridor for wildlife which ultimately end up on the road. Roadkill numbers increased when certain other physical barriers, such as cattle fences, were present, probably because these barriers were more penetrable than electric fencing. A series of mitigation measures are proposed to reduce the impacts of roads on wildlife in South Africa. These mitigation measures highlight the need to address the balance between the development of a country’s transport infrastructure and the conservation of its fauna. It is important that research on the impacts of roads becomes standardised to enable robust statistical comparisons which will provide a greater understanding of the potential threats to vertebrate biodiversity
- Full Text:
- Date Issued: 2013
- Authors: Collinson, Wendy Jane
- Date: 2013
- Subjects: Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5606 , http://hdl.handle.net/10962/d1002056 , Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Description: Despite evidence suggesting that road traffic is a major threat to biodiversity loss, very little is known about its actual impact on wildlife populations in South Africa. Globally, road density and traffic volumes are increasing, and although huge budgets are devoted to the construction and upgrading of roads, there is little or no allocation to mitigation measures for protecting fauna in most countries, particularly Africa. Further, no global standardised protocol exists for the rapid assessment of roadkill or the most economical and efficient approach for assessing roadkill rates. Using vehicle field trials, the reliability of detecting artificially deployed roadkill was assessed. Roadkill detection rates decreased significantly at speeds >50 km/h and were also significantly influenced by light conditions (i.e. detection success was greater when the sun was high) and the position of the roadkill on the road (i.e. smaller roadkill on verges were often missed). These results suggest that roadkill sampling was most effective between 1.5 hours after dawn and 1.5 hours before dusk and that driving at slower speeds (<50 km.h⁻ₑ) was required to detect roadkill. This protocol was implemented across three ecological seasons on a 100 km paved road and a 20 km unpaved road in the Greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa. Driven daily over a 120-day period (three periods consisting each of 40 days), a total of 1,027 roadkill were recorded. These comprised 162 species from all terrestrial vertebrate groups with birds being the most commonly encountered roadkill (50% of all incidents). The high numbers of vertebrates identified as roadkill suggests that road traffic could have potentially unsustainable impacts on wildlife populations and hence the biodiversity of the area. Seventeen variables were identified as possible determinants of roadkill occurrence with season, rainfall, minimum and maximum temperature, habitat type, grass height, grass density, fence type and vehicle type significantly influencing roadkill numbers. Significantly more roadkill were detected on the paved road (9.91/100km) than on the unpaved road (1.8/100km) probably because of greater traffic volumes and the increased speed that vehicles travelled on the paved road. Warmer temperatures and increased rainfall in the preceding 24 hours also increased road mortality numbers as animals tended to become more active during these times. Interestingly, more roadkill was detected in open roadside habitats compared to dense roadside habitats on both the paved and unpaved roads and when grass on the roadside verge was of intermediate height. Open habitat possibly may provide a natural corridor for wildlife which ultimately end up on the road. Roadkill numbers increased when certain other physical barriers, such as cattle fences, were present, probably because these barriers were more penetrable than electric fencing. A series of mitigation measures are proposed to reduce the impacts of roads on wildlife in South Africa. These mitigation measures highlight the need to address the balance between the development of a country’s transport infrastructure and the conservation of its fauna. It is important that research on the impacts of roads becomes standardised to enable robust statistical comparisons which will provide a greater understanding of the potential threats to vertebrate biodiversity
- Full Text:
- Date Issued: 2013
African traditional medicine-antiretroviral interactions : effects of Sutherlandia frutescens on the pharmacokinetics of Atazanavir
- Authors: Müller, Adrienne Carmel
- Date: 2011 , 2011-03-28
- Subjects: Antiretroviral agents , Medicinal plants , Traditional medicine , AIDS (Disease) -- Treatment , HIV infections -- Drug therapy , Drug interactions , Pharmacokinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3859 , http://hdl.handle.net/10962/d1013373
- Description: In response to the urgent call for investigations into antiretroviral (ARV)-African traditional medicine (ATM) interactions, this research was undertaken to ascertain whether chronic administration of the ATM, Sutherlandia frutescens (SF) may alter the bioavailability of the protease inhibitor (PI), atazanavir (ATV), which may impact on the safety or efficacy of the ARV. Prior to investigating a potential interaction between ATV and SF in vitro and in vivo, a high performance liquid chromatography method with ultraviolet detection (HPLC-UV) was developed and validated for the bioanalysis of ATV in human plasma and liver microsomes. An improved and efficient analytical method with minimal use of solvents and short run time was achieved in comparison to methods published in the literature. In addition, the method was selective, linear, accurate and precise for quantitative analysis of ATV in these studies. Molecular docking studies were conducted to compare the binding modes and affinities of ATV and two major SF constituents, Sutherlandioside B and Sutherlandin C, with the efflux transporter, P-glycoprotein (P-gp) and the CYP450 isoenzyme, CYP3A4 to determine the potential for these phytochemicals to competitively inhibit the binding of ATV to these two proteins, which are mediators of absorption and metabolism. These studies revealed that modulation of P-gp transport of ATV by Sutherlandioside B and Sutherlandin C was not likely to occur via competitive inhibition. The results further indicated that weak competitive inhibition of CYP3A4 may possibly occur in the presence of either of these two SF constituents. The Caco-2 cell line was used as an in vitro model of human intestinal absorption. Accumulation studies in these cells were conducted to ascertain whether extracts and constituents of SF have the ability to alter the absorption of ATV. The results showed that the aqueous extract of SF significantly reduced ATV accumulation, suggesting decreased ATV absorption, whilst a triterpenoid glycoside fraction isolated from SF exhibited an opposing effect. Analogous responses were elicited by the aqueous extract and a triterpenoid glycoside fraction in similar accumulation studies in P-gp overexpressing Madin–Darby Canine Kidney Strain II cells (MDCKII-MDR1), which signified that the effects of this extract and component on ATV transport in the Caco-2 cells were P-gp-mediated. The quantitative analysis of ATV in human liver microsomes after co-incubation with extracts and components of SF was conducted to determine the effects of SF on the metabolism of ATV. The aqueous and methanolic extracts of SF inhibited ATV metabolism, whilst the triterpenoid glycoside fraction had a converse effect. Analogous effects by the extracts were demonstrated in experiments conducted in CYP3A4-transfected microsomes, suggesting that the inhibition of ATV metabolism in the liver microsomes by these SF extracts was CYP3A4-mediated. A combination of Sutherlandiosides C and D also inhibited CYP3A4-mediated ATV metabolism, which was in contrast to the response elicited by the triterpenoid fraction in the liver microsomes, where other unidentified compounds, shown to be present therein, may have contributed to the activation of ATV metabolism. The in vitro studies revealed the potential for SF to alter the bioavailability of ATV, therefore a clinical study in which the effect of a multiple dose regimen of SF on the pharmacokinetics (PK) of a single dose of ATV was conducted in healthy male volunteers. The statistical analysis showed that the 90 % confidence intervals around the geometric mean ratios (ATV + SF/ATV alone) for both Cmax and AUC0-24 hours, fell well below the lower limit of the "no-effect" boundary of 0.8 – 1.25, implying that the bioavailability of ATV was significantly reduced in this cohort of subjects. It may thus be concluded that if the reduction in bioavailability observed in this clinical study is found to be clinically relevant, co-administration of SF commercial dosage forms and ATV in HIV/AIDS patients may potentially result in subtherapeutic ATV levels, which may in turn contribute to ATV resistance and/or treatment failure. This research has therefore highlighted the potential risk for toxicity or lack of efficacy of ARV regimens which may result when ATMs and PIs are used concurrently and that patients and health care practitioners alike should be aware of these perils.
- Full Text:
- Date Issued: 2011
- Authors: Müller, Adrienne Carmel
- Date: 2011 , 2011-03-28
- Subjects: Antiretroviral agents , Medicinal plants , Traditional medicine , AIDS (Disease) -- Treatment , HIV infections -- Drug therapy , Drug interactions , Pharmacokinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3859 , http://hdl.handle.net/10962/d1013373
- Description: In response to the urgent call for investigations into antiretroviral (ARV)-African traditional medicine (ATM) interactions, this research was undertaken to ascertain whether chronic administration of the ATM, Sutherlandia frutescens (SF) may alter the bioavailability of the protease inhibitor (PI), atazanavir (ATV), which may impact on the safety or efficacy of the ARV. Prior to investigating a potential interaction between ATV and SF in vitro and in vivo, a high performance liquid chromatography method with ultraviolet detection (HPLC-UV) was developed and validated for the bioanalysis of ATV in human plasma and liver microsomes. An improved and efficient analytical method with minimal use of solvents and short run time was achieved in comparison to methods published in the literature. In addition, the method was selective, linear, accurate and precise for quantitative analysis of ATV in these studies. Molecular docking studies were conducted to compare the binding modes and affinities of ATV and two major SF constituents, Sutherlandioside B and Sutherlandin C, with the efflux transporter, P-glycoprotein (P-gp) and the CYP450 isoenzyme, CYP3A4 to determine the potential for these phytochemicals to competitively inhibit the binding of ATV to these two proteins, which are mediators of absorption and metabolism. These studies revealed that modulation of P-gp transport of ATV by Sutherlandioside B and Sutherlandin C was not likely to occur via competitive inhibition. The results further indicated that weak competitive inhibition of CYP3A4 may possibly occur in the presence of either of these two SF constituents. The Caco-2 cell line was used as an in vitro model of human intestinal absorption. Accumulation studies in these cells were conducted to ascertain whether extracts and constituents of SF have the ability to alter the absorption of ATV. The results showed that the aqueous extract of SF significantly reduced ATV accumulation, suggesting decreased ATV absorption, whilst a triterpenoid glycoside fraction isolated from SF exhibited an opposing effect. Analogous responses were elicited by the aqueous extract and a triterpenoid glycoside fraction in similar accumulation studies in P-gp overexpressing Madin–Darby Canine Kidney Strain II cells (MDCKII-MDR1), which signified that the effects of this extract and component on ATV transport in the Caco-2 cells were P-gp-mediated. The quantitative analysis of ATV in human liver microsomes after co-incubation with extracts and components of SF was conducted to determine the effects of SF on the metabolism of ATV. The aqueous and methanolic extracts of SF inhibited ATV metabolism, whilst the triterpenoid glycoside fraction had a converse effect. Analogous effects by the extracts were demonstrated in experiments conducted in CYP3A4-transfected microsomes, suggesting that the inhibition of ATV metabolism in the liver microsomes by these SF extracts was CYP3A4-mediated. A combination of Sutherlandiosides C and D also inhibited CYP3A4-mediated ATV metabolism, which was in contrast to the response elicited by the triterpenoid fraction in the liver microsomes, where other unidentified compounds, shown to be present therein, may have contributed to the activation of ATV metabolism. The in vitro studies revealed the potential for SF to alter the bioavailability of ATV, therefore a clinical study in which the effect of a multiple dose regimen of SF on the pharmacokinetics (PK) of a single dose of ATV was conducted in healthy male volunteers. The statistical analysis showed that the 90 % confidence intervals around the geometric mean ratios (ATV + SF/ATV alone) for both Cmax and AUC0-24 hours, fell well below the lower limit of the "no-effect" boundary of 0.8 – 1.25, implying that the bioavailability of ATV was significantly reduced in this cohort of subjects. It may thus be concluded that if the reduction in bioavailability observed in this clinical study is found to be clinically relevant, co-administration of SF commercial dosage forms and ATV in HIV/AIDS patients may potentially result in subtherapeutic ATV levels, which may in turn contribute to ATV resistance and/or treatment failure. This research has therefore highlighted the potential risk for toxicity or lack of efficacy of ARV regimens which may result when ATMs and PIs are used concurrently and that patients and health care practitioners alike should be aware of these perils.
- Full Text:
- Date Issued: 2011
Studies on an autolysin produced by clostridium acetobutylicum
- Authors: Webster, Jocelyn Rowena
- Date: 1981
- Subjects: Clostridium acetobutylicum , Autolysis , Bacteriocins , Proteins -- Synthesis , DNA -- Synthesis , RNA -- Synthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3893 , http://hdl.handle.net/10962/d1003724
- Description: An extracellular bacteriocin-like substance produced by Clostridium acetobutylicum was detected during studies on an industrial fermentation process. The bacteriocin-like substance was not inducible by either ultraviolet light or mitomycin C, and its production was not associated with the induction of a protease. Studies on the mode of action of the bacteriocin-like substance indicated that it had no significant effect on DNA, RNA, or protein synthesis, and it did not cause the loss of intracellular ATP. However, the bacteriocin-like substance was able to lyse SDS-treated cells and cell walls of C. acetobutylicum and was identified as an autolysin. Some of the characteristics of this extracellular autolysin were determined, and after purification it was shown to be a glycoprotein with a molecular weight of 28 000.
- Full Text:
- Date Issued: 1981
- Authors: Webster, Jocelyn Rowena
- Date: 1981
- Subjects: Clostridium acetobutylicum , Autolysis , Bacteriocins , Proteins -- Synthesis , DNA -- Synthesis , RNA -- Synthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3893 , http://hdl.handle.net/10962/d1003724
- Description: An extracellular bacteriocin-like substance produced by Clostridium acetobutylicum was detected during studies on an industrial fermentation process. The bacteriocin-like substance was not inducible by either ultraviolet light or mitomycin C, and its production was not associated with the induction of a protease. Studies on the mode of action of the bacteriocin-like substance indicated that it had no significant effect on DNA, RNA, or protein synthesis, and it did not cause the loss of intracellular ATP. However, the bacteriocin-like substance was able to lyse SDS-treated cells and cell walls of C. acetobutylicum and was identified as an autolysin. Some of the characteristics of this extracellular autolysin were determined, and after purification it was shown to be a glycoprotein with a molecular weight of 28 000.
- Full Text:
- Date Issued: 1981
An investigation of stakeholder participation and learning in two schools within the Seychelles Eco-School programme
- Authors: Emilie, Shane Antonio
- Date: 2014
- Subjects: Environmental education -- Seychelles Schools -- Environmental aspects -- Seychelles Education, Primary -- Parent participation -- Seychelles Education, Secondary -- Parent participation -- Seychelles Student participation in administration -- Education (Primary) -- Seychelles Student participation in administration -- Education (Secondary) -- Seychelles Student participation in curriculum planning -- Education (Primary) -- Seychelles Student participation in curriculum planning -- Education (Secondary) -- Seychelles Education, Primary -- Seychelles Education, Secondary -- Seychelles
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1969 , http://hdl.handle.net/10962/d1011961
- Description: The aim of this study was to investigate stakeholder participation and learning in the Seychelles Eco-School programme within a primary school context and a secondary school context. Findings from each Eco-School have been presented in two case studies with the goal to explore and describe how teachers, students, parents and organizations are participating and learning in the Eco-School programme. Six elements of school community were used to deepen understanding of the participatory and learning processes in each Eco-School, namely, leadership, management and administration, curriculum planning, teaching and learning, resource use and management, management of physical surrounds of the school and networks and partnerships. Some of the contextual variables in each Eco-School that were constraining and enabling stakeholder participation and learning in the programme have also been explored within this study. Data in this study was generated from historical documents analysed, semi-structured interviews, focus group discussions and field notes. Data was also generated from questionnaires completed by organizations involved in the programme at each Eco- School. Data was analysed in two phases, the first phase involved reading across data generated from the methods mentioned above to organize the data under broad themes in relation to the elements of school community. The second phase of analysis involved the use of the conceptual framework of situating learning in a community of practice to interpret and discuss the participatory and learning processes across the two cases. The study showed that in each Eco-School there is a community of practice with the active involvement of teachers and students and the occasional involvement of parents and organizations. Students and adults are learning as they engage together in classroom and field-work interactions, environmental projects, environmental activities to commemorate environmental theme days, environmental campaigns and co-curricular activities through the practices of each Eco-School community. It was also discovered that students and adults are making different contributions in the Eco-School community based on their level of participation in the programme. It is hoped that the findings in this research contribute information regarding community participation in environmental education programmes like the Seychelles Eco-School programme. In addition, findings will inform the Seychelles Government and its partners to consider the possibility of enhancing school and community partnerships to respond to some of the challenges of participation and learning in the Eco-School programme.
- Full Text:
- Date Issued: 2014
- Authors: Emilie, Shane Antonio
- Date: 2014
- Subjects: Environmental education -- Seychelles Schools -- Environmental aspects -- Seychelles Education, Primary -- Parent participation -- Seychelles Education, Secondary -- Parent participation -- Seychelles Student participation in administration -- Education (Primary) -- Seychelles Student participation in administration -- Education (Secondary) -- Seychelles Student participation in curriculum planning -- Education (Primary) -- Seychelles Student participation in curriculum planning -- Education (Secondary) -- Seychelles Education, Primary -- Seychelles Education, Secondary -- Seychelles
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1969 , http://hdl.handle.net/10962/d1011961
- Description: The aim of this study was to investigate stakeholder participation and learning in the Seychelles Eco-School programme within a primary school context and a secondary school context. Findings from each Eco-School have been presented in two case studies with the goal to explore and describe how teachers, students, parents and organizations are participating and learning in the Eco-School programme. Six elements of school community were used to deepen understanding of the participatory and learning processes in each Eco-School, namely, leadership, management and administration, curriculum planning, teaching and learning, resource use and management, management of physical surrounds of the school and networks and partnerships. Some of the contextual variables in each Eco-School that were constraining and enabling stakeholder participation and learning in the programme have also been explored within this study. Data in this study was generated from historical documents analysed, semi-structured interviews, focus group discussions and field notes. Data was also generated from questionnaires completed by organizations involved in the programme at each Eco- School. Data was analysed in two phases, the first phase involved reading across data generated from the methods mentioned above to organize the data under broad themes in relation to the elements of school community. The second phase of analysis involved the use of the conceptual framework of situating learning in a community of practice to interpret and discuss the participatory and learning processes across the two cases. The study showed that in each Eco-School there is a community of practice with the active involvement of teachers and students and the occasional involvement of parents and organizations. Students and adults are learning as they engage together in classroom and field-work interactions, environmental projects, environmental activities to commemorate environmental theme days, environmental campaigns and co-curricular activities through the practices of each Eco-School community. It was also discovered that students and adults are making different contributions in the Eco-School community based on their level of participation in the programme. It is hoped that the findings in this research contribute information regarding community participation in environmental education programmes like the Seychelles Eco-School programme. In addition, findings will inform the Seychelles Government and its partners to consider the possibility of enhancing school and community partnerships to respond to some of the challenges of participation and learning in the Eco-School programme.
- Full Text:
- Date Issued: 2014
Rhodes University Graduation Ceremony 1967
- Authors: Rhodes University
- Date: 1967
- Language: English
- Type: text
- Identifier: vital:8101 , http://hdl.handle.net/10962/d1004436
- Description: Rhodes University Graduation Ceremonies on Friday 7th April 1967 at 8 p.m. [and] Saturday 8th April 1967 at 10:30 a.m. in the University Great Hall.
- Full Text:
- Date Issued: 1967
- Authors: Rhodes University
- Date: 1967
- Language: English
- Type: text
- Identifier: vital:8101 , http://hdl.handle.net/10962/d1004436
- Description: Rhodes University Graduation Ceremonies on Friday 7th April 1967 at 8 p.m. [and] Saturday 8th April 1967 at 10:30 a.m. in the University Great Hall.
- Full Text:
- Date Issued: 1967