Records management at Albany Museum, Grahamstown, Eastern Cape Province, South Africa
- Authors: Obileke , Ugonna Christiana
- Date: 2019
- Subjects: Records -- Management
- Language: English
- Type: Thesis , Masters , M.LIS
- Identifier: http://hdl.handle.net/10353/17663 , vital:41133
- Description: This study is about records management at the Albany Museum in Grahamstown, in the Eastern Cape Province of South Africa. The objectives of the study were to find out the extent to which records management is practised; to find out what records management programme exist; to find out the infrastructure available for records management; and to identify the challenges, if any, facing records management in Albany Museum. The records life cycle and the records continuum formed the theoretical framework. The study adopted qualitative and quantitative research approaches. The state accountant, senior administrator, fossil excavator, receptionist and the postgraduate researcher formed the sample of the study. Quantitative data were coded and analysed using Microsoft Office Excel 2013 while the qualitative data were analysed using thematic analysis. The major findings showed that records management Albany Museum is very weak, which makes it difficult for the museum to derive or benefit from effective records management as well as experiencing delays in decision-making, loss and misplacement of records. Also, it was revealed that there was no personnel responsible for the records management. The study recommended for recruitment of personnel for records management in the museum to improve on records management as well as the development of a functioning records management program
- Full Text:
- Date Issued: 2019
- Authors: Obileke , Ugonna Christiana
- Date: 2019
- Subjects: Records -- Management
- Language: English
- Type: Thesis , Masters , M.LIS
- Identifier: http://hdl.handle.net/10353/17663 , vital:41133
- Description: This study is about records management at the Albany Museum in Grahamstown, in the Eastern Cape Province of South Africa. The objectives of the study were to find out the extent to which records management is practised; to find out what records management programme exist; to find out the infrastructure available for records management; and to identify the challenges, if any, facing records management in Albany Museum. The records life cycle and the records continuum formed the theoretical framework. The study adopted qualitative and quantitative research approaches. The state accountant, senior administrator, fossil excavator, receptionist and the postgraduate researcher formed the sample of the study. Quantitative data were coded and analysed using Microsoft Office Excel 2013 while the qualitative data were analysed using thematic analysis. The major findings showed that records management Albany Museum is very weak, which makes it difficult for the museum to derive or benefit from effective records management as well as experiencing delays in decision-making, loss and misplacement of records. Also, it was revealed that there was no personnel responsible for the records management. The study recommended for recruitment of personnel for records management in the museum to improve on records management as well as the development of a functioning records management program
- Full Text:
- Date Issued: 2019
Insect pests of cultivated and wild olives, and some of their natural enemies, in the Eastern Cape, South Africa
- Authors: Mkize, Nolwazi
- Date: 2009
- Subjects: Pests -- Control -- South Africa -- Eastern Cape Olive -- Diseases and pests -- South Africa -- Eastern Cape Agriculture -- South Africa -- Eastern Cape Fruit-flies -- South Africa -- Eastern Cape Tephritidae Flea beetles Lace bugs
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5717 , http://hdl.handle.net/10962/d1005403
- Description: This thesis has two focuses. The first problem facing the olive industry in the Eastern Cape is the growers’ perceptions of both what the industry will provide them and what a pest management program might entail. The second focus is the biology of olive pests in the Eastern Cape in terms of understanding their populations and their natural enemies on private farms, with future hopes of understanding how Integrated Pest Management strategies can be developed for this crop. Eastern Cape private farmers, small-scale farmers and workers from agricultural training institutions were interviewed regarding the history and cultivation of the local olive crop. Only one commercially viable olive grove was identified; other groves were small, experimental pilot ventures. The introduction of olives to small-scale farmers and agricultural training schools was generally a top-down initiative that led to a lack of sense of ownership and the trees being neglected. Other problems included poor human capital; poor financial capital; lack of adequate support; lack of knowledge transfer and stability; lack of communication and evaluation procedures of the project; miscommunication; and finally, olive pests. Apart from hesitancy to plant at a commercial scale, the main problem facing private farmers (Varnam Farm, Hewlands Farm and Springvale Farm) was pests. Therefore an investigation of pests from private farms was conducted ranging from collection of cultivated and wild olive fruit and flea beetle larvae for parasitism, trapping systems both for fruit flies and olive flea beetle adults. A survey of olive fruits yielded larval fruit flies of the families Tephritidae (Bactrocera oleae (Rossi), B. biguttula (Bezzi) and Ceratitis capitata (Wiedemann)) and Drosophilidae (Drosophila melanogaster (Meigen)) from wild olives (O. europaea cuspidata (Wall. ex G. Don) Cif.) but none from cultivated olives (O. e. europaea L.). Braconid wasps (Opiinae and Braconinae) were reared only from fruits containing B. oleae and B. biguttula. This suggests that B. oleae is not of economic significance in the Eastern Cape, perhaps because it is controlled to a significant level by natural enemies, but B. biguttula may be a potential economic pest. A survey of adult fruit flies using ChamP traps baited with ammonium bicarbonate and spiroketal capsules and Sensus trap baited with methyl eugenol and Questlure confirmed the relative importance of B. biguttula over B. oleae. ChamP traps were over 50 times better than Sensus traps for mass trapping of B. biguttula but both were ineffective for trapping B. oleae and C. capitata. Six indigenous flea beetles of the genus Argopistes Motschulsky (Chrysomelidae: Alticinae) were found, three described by Bryant in 1922 and 1944 and three new species. Their morphology was investigated by scanning electron microscopy and mutivariate morphometric analysis. The leaf-mining larvae are pests of wild and cultivated olives in South Africa and threaten the local olive industry. At Springvale Farm, A. oleae Bryant and A. sexvittatus Bryant preferred the upper parts of trees, near new leaves. Pseudophanomeris inopinatus (Blkb.) (Braconidae) was reared from 23 Argopistes larvae. The beetle larvae might not be controlled to a significant level by natural enemies because the rate of parasitism was low. The olive flea beetles showed no attraction to traps containing various volatile compounds as baits. The lace bug, Plerochila australis Distant (Tingidae), was sometimes a pest. It showed a preference for the underside of leaves on the lower parts of the trees. A moth, Palpita unionalis Hübner (Crambidae), was reared in very low numbers and without parasitoids. A twig-boring beetle larva, chalcidoid parasitoids and seed wasps of the families Eurytomidae, Ormyridae and Eupelmidae were also recorded.
- Full Text:
- Date Issued: 2009
- Authors: Mkize, Nolwazi
- Date: 2009
- Subjects: Pests -- Control -- South Africa -- Eastern Cape Olive -- Diseases and pests -- South Africa -- Eastern Cape Agriculture -- South Africa -- Eastern Cape Fruit-flies -- South Africa -- Eastern Cape Tephritidae Flea beetles Lace bugs
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5717 , http://hdl.handle.net/10962/d1005403
- Description: This thesis has two focuses. The first problem facing the olive industry in the Eastern Cape is the growers’ perceptions of both what the industry will provide them and what a pest management program might entail. The second focus is the biology of olive pests in the Eastern Cape in terms of understanding their populations and their natural enemies on private farms, with future hopes of understanding how Integrated Pest Management strategies can be developed for this crop. Eastern Cape private farmers, small-scale farmers and workers from agricultural training institutions were interviewed regarding the history and cultivation of the local olive crop. Only one commercially viable olive grove was identified; other groves were small, experimental pilot ventures. The introduction of olives to small-scale farmers and agricultural training schools was generally a top-down initiative that led to a lack of sense of ownership and the trees being neglected. Other problems included poor human capital; poor financial capital; lack of adequate support; lack of knowledge transfer and stability; lack of communication and evaluation procedures of the project; miscommunication; and finally, olive pests. Apart from hesitancy to plant at a commercial scale, the main problem facing private farmers (Varnam Farm, Hewlands Farm and Springvale Farm) was pests. Therefore an investigation of pests from private farms was conducted ranging from collection of cultivated and wild olive fruit and flea beetle larvae for parasitism, trapping systems both for fruit flies and olive flea beetle adults. A survey of olive fruits yielded larval fruit flies of the families Tephritidae (Bactrocera oleae (Rossi), B. biguttula (Bezzi) and Ceratitis capitata (Wiedemann)) and Drosophilidae (Drosophila melanogaster (Meigen)) from wild olives (O. europaea cuspidata (Wall. ex G. Don) Cif.) but none from cultivated olives (O. e. europaea L.). Braconid wasps (Opiinae and Braconinae) were reared only from fruits containing B. oleae and B. biguttula. This suggests that B. oleae is not of economic significance in the Eastern Cape, perhaps because it is controlled to a significant level by natural enemies, but B. biguttula may be a potential economic pest. A survey of adult fruit flies using ChamP traps baited with ammonium bicarbonate and spiroketal capsules and Sensus trap baited with methyl eugenol and Questlure confirmed the relative importance of B. biguttula over B. oleae. ChamP traps were over 50 times better than Sensus traps for mass trapping of B. biguttula but both were ineffective for trapping B. oleae and C. capitata. Six indigenous flea beetles of the genus Argopistes Motschulsky (Chrysomelidae: Alticinae) were found, three described by Bryant in 1922 and 1944 and three new species. Their morphology was investigated by scanning electron microscopy and mutivariate morphometric analysis. The leaf-mining larvae are pests of wild and cultivated olives in South Africa and threaten the local olive industry. At Springvale Farm, A. oleae Bryant and A. sexvittatus Bryant preferred the upper parts of trees, near new leaves. Pseudophanomeris inopinatus (Blkb.) (Braconidae) was reared from 23 Argopistes larvae. The beetle larvae might not be controlled to a significant level by natural enemies because the rate of parasitism was low. The olive flea beetles showed no attraction to traps containing various volatile compounds as baits. The lace bug, Plerochila australis Distant (Tingidae), was sometimes a pest. It showed a preference for the underside of leaves on the lower parts of the trees. A moth, Palpita unionalis Hübner (Crambidae), was reared in very low numbers and without parasitoids. A twig-boring beetle larva, chalcidoid parasitoids and seed wasps of the families Eurytomidae, Ormyridae and Eupelmidae were also recorded.
- Full Text:
- Date Issued: 2009
Phytochemical, antibacterial and pharmacological investigations of Clausena Anisata (Wild). Hook : bone of the medicinal plants used for traditional treatment of "tuberculosis" in Eastern Cape, South Africa
- Authors: Lawal, Ibraheem O
- Date: 2015
- Subjects: Traditional medicine--South Africa--Eastern Cape Tuberculosis--Treatment--South Africa--Eastern Cape Mycobacterial diseases--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Ethnobotany
- Identifier: http://hdl.handle.net/10353/11828 , vital:39110
- Description: Clausena anisata (Willd) Hook, is the only species out of the 15 species of the genus found in the African continent and is regarded as a threatened species in this area of Southern region of Africa. Its distribution spread across Africa to south-east Asia. C. anisata has a wide range of ethno-pharmacological importance. Despite the numerous studies on the pharmacological profile of the plant, there is still dearth of scientific literature on the foliar micro-morphology of this valuable medicinal plant. The morphorlogical structure of the leaves of C. anisata was examined under Light Microscopy (LM), Scanning Electron Microscopy (SEM) and Energy Dispersive x-ray Spectroscopy (EDS) following standard procedures. LM indicates the types of stomata of the leaves (amphistomatic). SEM revealed the presence of the whip like trichomes with its uniqueness to the plants. EDS showed the chemical composition of the foliar appendages which indicated the presence Ca, Mg, S, and Fe. The indication of the elements could probably be helpful in the herbal drug regulation based on the mineral composition and in return reduced herbal drug toxicity.
- Full Text:
- Date Issued: 2015
- Authors: Lawal, Ibraheem O
- Date: 2015
- Subjects: Traditional medicine--South Africa--Eastern Cape Tuberculosis--Treatment--South Africa--Eastern Cape Mycobacterial diseases--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Ethnobotany
- Identifier: http://hdl.handle.net/10353/11828 , vital:39110
- Description: Clausena anisata (Willd) Hook, is the only species out of the 15 species of the genus found in the African continent and is regarded as a threatened species in this area of Southern region of Africa. Its distribution spread across Africa to south-east Asia. C. anisata has a wide range of ethno-pharmacological importance. Despite the numerous studies on the pharmacological profile of the plant, there is still dearth of scientific literature on the foliar micro-morphology of this valuable medicinal plant. The morphorlogical structure of the leaves of C. anisata was examined under Light Microscopy (LM), Scanning Electron Microscopy (SEM) and Energy Dispersive x-ray Spectroscopy (EDS) following standard procedures. LM indicates the types of stomata of the leaves (amphistomatic). SEM revealed the presence of the whip like trichomes with its uniqueness to the plants. EDS showed the chemical composition of the foliar appendages which indicated the presence Ca, Mg, S, and Fe. The indication of the elements could probably be helpful in the herbal drug regulation based on the mineral composition and in return reduced herbal drug toxicity.
- Full Text:
- Date Issued: 2015
A neural network based ionospheric model for the bottomside electron density profile over Grahamstown, South Africa
- Authors: McKinnell, L A
- Date: 2003
- Subjects: Neural networks (Computer science) Ionospheric electron density -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5477 , http://hdl.handle.net/10962/d1005262
- Description: This thesis describes the development and application of a neural network based ionospheric model for the bottomside electron density profile over Grahamstown, South Africa. All available ionospheric data from the archives of the Grahamstown (33.32ºS, 26.50ºE) ionospheric station were used for training neural networks (NNs) to predict the parameters required to produce the final profile. Inputs to the model, called the LAM model, are day number, hour, and measures of solar and magnetic activity. The output is a mathematical description of the bottomside electron density profile for that particular input set. The two main ionospheric layers, the E and F layers, are predicted separately and then combined at the final stage. For each layer, NNs have been trained to predict the individual ionospheric characteristics and coefficients that were required to describe the layer profile. NNs were also applied to the task of determining the hours between which an E layer is measurable by a groundbased ionosonde and the probability of the existence of an F1 layer. The F1 probability NN is innovative in that it provides information on the existence of the F1 layer as well as the probability of that layer being in a L-condition state - the state where an F1 layer is present on an ionogram but it is not possible to record any F1 parameters. In the event of an L-condition state being predicted as probable, an L algorithm has been designed to alter the shape of the profile to reflect this state. A smoothing algorithm has been implemented to remove discontinuities at the F1-F2 boundary and ensure that the profile represents realistic ionospheric behaviour in the F1 region. Tests show that the LAM model is more successful at predicting Grahamstown electron density profiles for a particular set of inputs than the International Reference Ionosphere (IRI). It is anticipated that the LAM model will be used as a tool in the pin-pointing of hostile HF transmitters, known as single-site location.
- Full Text:
- Date Issued: 2003
- Authors: McKinnell, L A
- Date: 2003
- Subjects: Neural networks (Computer science) Ionospheric electron density -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5477 , http://hdl.handle.net/10962/d1005262
- Description: This thesis describes the development and application of a neural network based ionospheric model for the bottomside electron density profile over Grahamstown, South Africa. All available ionospheric data from the archives of the Grahamstown (33.32ºS, 26.50ºE) ionospheric station were used for training neural networks (NNs) to predict the parameters required to produce the final profile. Inputs to the model, called the LAM model, are day number, hour, and measures of solar and magnetic activity. The output is a mathematical description of the bottomside electron density profile for that particular input set. The two main ionospheric layers, the E and F layers, are predicted separately and then combined at the final stage. For each layer, NNs have been trained to predict the individual ionospheric characteristics and coefficients that were required to describe the layer profile. NNs were also applied to the task of determining the hours between which an E layer is measurable by a groundbased ionosonde and the probability of the existence of an F1 layer. The F1 probability NN is innovative in that it provides information on the existence of the F1 layer as well as the probability of that layer being in a L-condition state - the state where an F1 layer is present on an ionogram but it is not possible to record any F1 parameters. In the event of an L-condition state being predicted as probable, an L algorithm has been designed to alter the shape of the profile to reflect this state. A smoothing algorithm has been implemented to remove discontinuities at the F1-F2 boundary and ensure that the profile represents realistic ionospheric behaviour in the F1 region. Tests show that the LAM model is more successful at predicting Grahamstown electron density profiles for a particular set of inputs than the International Reference Ionosphere (IRI). It is anticipated that the LAM model will be used as a tool in the pin-pointing of hostile HF transmitters, known as single-site location.
- Full Text:
- Date Issued: 2003
Revised parameter estimation methods for the Pitman monthly rainfall-runoff model
- Authors: Kapangaziwiri, Evison
- Date: 2008
- Subjects: Rain and rainfall -- Mathematical models , Runoff -- Mathematical models , Hydrology -- Mathematical models , Water supply -- South Africa , Water resources development -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6033 , http://hdl.handle.net/10962/d1006172 , Rain and rainfall -- Mathematical models , Runoff -- Mathematical models , Hydrology -- Mathematical models , Water supply -- South Africa , Water resources development -- South Africa
- Description: In recent years, increased demands have been placed on hydrologists to find the most effective methods of making predictions of hydrologic variables in ungauged basins. A huge part of the southern African region is ungauged and, in gauged basins, the extent to which observed flows represent natural flows is unknown, given unquantified upstream activities. The need to exploit water resources for social and economic development, considered in the light of water scarcity forecasts for the region, makes the reliable quantification of water resources a priority. Contemporary approaches to the problem of hydrological prediction in ungauged basins in the region have relied heavily on calibration against a limited gauged streamflow database and somewhat subjective parameter regionalizations using areas of assumed hydrological similarity. The reliance of these approaches on limited historical records, often of dubious quality, introduces uncertainty in water resources decisions. Thus, it is necessary to develop methods of estimating model parameters that are less reliant on calibration. This thesis addresses the question of whether physical basin properties and the role they play in runoff generation processes can be used directly in the estimation of parameter values of the Pitman monthly rainfall-runoff model. A physically-based approach to estimating the soil moisture accounting and runoff parameters of a conceptual, monthly time-step rainfall-runoff model is proposed. The study investigates the physical meaning of the model parameters, establishes linkages between parameter values and basin physical properties and develops relationships and equations for estimating the parameters taking into account the spatial and temporal scales used in typical model applications. The estimationmethods are then tested in selected gauged basins in southern Africa and the results of model simulations evaluated against historical observed flows. The results of 71 basins chosen from the southern African region suggest that it is possible to directly estimate hydrologically relevant parameters for the Pitman model from physical basin attributes. For South Africa, the statistical and visual fit of the simulations using the revised parameters were at least as good as the current regional sets, albeit the parameter sets being different. In the other countries where no regionalized parameter sets currently exist, simulations were equally good. The availability, within the southern African region, of the appropriate physical basin data and the disparities in the spatial scales and the levels of detail of the data currently available were identified as potential sources of uncertainty. GIS and remote sensing technologies and a widespread use of this revised approach are expected to facilitate access to these data.
- Full Text:
- Date Issued: 2008
- Authors: Kapangaziwiri, Evison
- Date: 2008
- Subjects: Rain and rainfall -- Mathematical models , Runoff -- Mathematical models , Hydrology -- Mathematical models , Water supply -- South Africa , Water resources development -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6033 , http://hdl.handle.net/10962/d1006172 , Rain and rainfall -- Mathematical models , Runoff -- Mathematical models , Hydrology -- Mathematical models , Water supply -- South Africa , Water resources development -- South Africa
- Description: In recent years, increased demands have been placed on hydrologists to find the most effective methods of making predictions of hydrologic variables in ungauged basins. A huge part of the southern African region is ungauged and, in gauged basins, the extent to which observed flows represent natural flows is unknown, given unquantified upstream activities. The need to exploit water resources for social and economic development, considered in the light of water scarcity forecasts for the region, makes the reliable quantification of water resources a priority. Contemporary approaches to the problem of hydrological prediction in ungauged basins in the region have relied heavily on calibration against a limited gauged streamflow database and somewhat subjective parameter regionalizations using areas of assumed hydrological similarity. The reliance of these approaches on limited historical records, often of dubious quality, introduces uncertainty in water resources decisions. Thus, it is necessary to develop methods of estimating model parameters that are less reliant on calibration. This thesis addresses the question of whether physical basin properties and the role they play in runoff generation processes can be used directly in the estimation of parameter values of the Pitman monthly rainfall-runoff model. A physically-based approach to estimating the soil moisture accounting and runoff parameters of a conceptual, monthly time-step rainfall-runoff model is proposed. The study investigates the physical meaning of the model parameters, establishes linkages between parameter values and basin physical properties and develops relationships and equations for estimating the parameters taking into account the spatial and temporal scales used in typical model applications. The estimationmethods are then tested in selected gauged basins in southern Africa and the results of model simulations evaluated against historical observed flows. The results of 71 basins chosen from the southern African region suggest that it is possible to directly estimate hydrologically relevant parameters for the Pitman model from physical basin attributes. For South Africa, the statistical and visual fit of the simulations using the revised parameters were at least as good as the current regional sets, albeit the parameter sets being different. In the other countries where no regionalized parameter sets currently exist, simulations were equally good. The availability, within the southern African region, of the appropriate physical basin data and the disparities in the spatial scales and the levels of detail of the data currently available were identified as potential sources of uncertainty. GIS and remote sensing technologies and a widespread use of this revised approach are expected to facilitate access to these data.
- Full Text:
- Date Issued: 2008
Numerical relativity on cosmological past null cones
- Van der Walt, Petrus Johannes
- Authors: Van der Walt, Petrus Johannes
- Date: 2013
- Subjects: Cosmology Numerical calculations General relativity (Physics) -- Mathematics Einstein field equations Gravity Gravitational waves Horizon
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5396 , http://hdl.handle.net/10962/d1002959
- Description: The observational approach to cosmology is the endeavour to reconstruct the geometry of the Universe using only data that is theoretically verifiable within the causal boundaries of a cosmological observer. Using this approach, it was shown in [36] that given ideal cosmological observations, the only essential assumption necessary to determine the geometry of the Universe is a theory of gravity. Assuming General Relativity, the full set of Einstein field equations (EFEs) can be used to reconstruct the geometry of the Universe using direct observations on the past null cone (PNC) as initial conditions. Observationally and theoretically this is a very ambitious task and therefore, current developments have been restricted to spherically symmetric dust models while only relaxing the usual assumption of homogeneity in the radial direction. These restricted models are important for the development of theoretical foundations and also useful as verification models since they avoid the circularity of verifying what has already been assumed. The work presented in this thesis is the development of such a model where numerical relativity (NR) is used to simulate the observable universe. Similar to the work of Ellis and co-workers [36], a reference frame based on the PNC is used. The reference frame used here, however, is based on that of the characteristic formalism of NR, which has developed for calculating the propagation of gravitational waves. This provides a formalism that is well established in NR, making the use of existing algorithms possible. The Bondi-Sachs coordinates of the characteristic formalism is, however, not suitable for calculations beyond the observer apparent horizon (AH) since the diameter distance used as a radial coordinate becomes multi-valued when the cosmological PNC reconverges in the history of a universe, smaller in the past. With this taken into consideration, the Bondi-Sachs characteristic formalism is implemented for cosmology and the problem approaching the AH is investigated. Further developments address the limitations approaching the AH by introducing a metric based on the Bondi-Sachs metric where the radial coordinate is replaced with an affine parameter. The model is derived with a cosmological constant Λ incorporated into the EFEs where Λ is taken as a parameter of the theory of gravity rather than as a matter source term. Similar to the conventional characteristic formalism, this model consists of a system of differential equations for numerically evolving the EFEs as a characteristic initial value problem (CIVP). A numerical code implemented for the method has been found to be second order convergent. This code enables simulations of different models given identical data on the initial null cone and provides a method to investigate their physical consistency within the causally connected region of our current PNC. These developments closely follow existing 3D schemes developed for gravitational wave simulations, which should make it natural to extend the affine CIVP beyond spherical symmetric simulations. The developments presented in this thesis is an extended version of two papers published earlier.
- Full Text:
- Date Issued: 2013
- Authors: Van der Walt, Petrus Johannes
- Date: 2013
- Subjects: Cosmology Numerical calculations General relativity (Physics) -- Mathematics Einstein field equations Gravity Gravitational waves Horizon
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5396 , http://hdl.handle.net/10962/d1002959
- Description: The observational approach to cosmology is the endeavour to reconstruct the geometry of the Universe using only data that is theoretically verifiable within the causal boundaries of a cosmological observer. Using this approach, it was shown in [36] that given ideal cosmological observations, the only essential assumption necessary to determine the geometry of the Universe is a theory of gravity. Assuming General Relativity, the full set of Einstein field equations (EFEs) can be used to reconstruct the geometry of the Universe using direct observations on the past null cone (PNC) as initial conditions. Observationally and theoretically this is a very ambitious task and therefore, current developments have been restricted to spherically symmetric dust models while only relaxing the usual assumption of homogeneity in the radial direction. These restricted models are important for the development of theoretical foundations and also useful as verification models since they avoid the circularity of verifying what has already been assumed. The work presented in this thesis is the development of such a model where numerical relativity (NR) is used to simulate the observable universe. Similar to the work of Ellis and co-workers [36], a reference frame based on the PNC is used. The reference frame used here, however, is based on that of the characteristic formalism of NR, which has developed for calculating the propagation of gravitational waves. This provides a formalism that is well established in NR, making the use of existing algorithms possible. The Bondi-Sachs coordinates of the characteristic formalism is, however, not suitable for calculations beyond the observer apparent horizon (AH) since the diameter distance used as a radial coordinate becomes multi-valued when the cosmological PNC reconverges in the history of a universe, smaller in the past. With this taken into consideration, the Bondi-Sachs characteristic formalism is implemented for cosmology and the problem approaching the AH is investigated. Further developments address the limitations approaching the AH by introducing a metric based on the Bondi-Sachs metric where the radial coordinate is replaced with an affine parameter. The model is derived with a cosmological constant Λ incorporated into the EFEs where Λ is taken as a parameter of the theory of gravity rather than as a matter source term. Similar to the conventional characteristic formalism, this model consists of a system of differential equations for numerically evolving the EFEs as a characteristic initial value problem (CIVP). A numerical code implemented for the method has been found to be second order convergent. This code enables simulations of different models given identical data on the initial null cone and provides a method to investigate their physical consistency within the causally connected region of our current PNC. These developments closely follow existing 3D schemes developed for gravitational wave simulations, which should make it natural to extend the affine CIVP beyond spherical symmetric simulations. The developments presented in this thesis is an extended version of two papers published earlier.
- Full Text:
- Date Issued: 2013
African traditional medicines-antiretroviral drug interactions: the effect of African potato (Hypoxis hemerocallidea) on the pharmacokinetics of efavirenz in humans
- Authors: Mogatle, Seloi
- Date: 2009
- Subjects: Potatoes -- Africa Potatoes -- Therapeutic use Medicinal plants Traditional medicine AIDS (Disease) -- Treatment HIV infections -- Drug therapy Drug interactions Antiretroviral agents Pharmacokinetics Hypoxidaceae -- Therapeutic use High performance liquid chromatography
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3773 , http://hdl.handle.net/10962/d1003251
- Description: African Potato (Hypoxis hemerocallidea), (AP) is an African traditional medicine (TM) that is commonly used for various nutritional/medicinal purposes and also by people infected with the human immuno deficiency virus HIV and AIDS patients as an immune booster. The use of AP has also been recommended by the former Minister of Health of South Africa for use by HIV positive people. The main phytochemical component of AP is a norlignan glucoside, hypoxoside, and other relatively minor components have also been reported. A recent in vitro study reported the effects of AP extracts, hypoxoside and rooperol (the metabolite of hypoxoside) on human metabolic enzymes such as the cytochrome P450 (CYP450) group of enzymes and also on the transporter protein, p-glycoprotein (P-gp). This research focussed on investigating the clinical significance of those in vitro effects on the pharmacokinetics of efavirenz (EFV) in humans. EFV was chosen as the substrate drug because it is in first-line regimen of treatment of HIV/AIDS in South Africa, and also has been reported to be a substrate for the specific CYP isozymes, 3A4 and 2B6, in common with APs metabolic involvement with 3A4. A high performance liquid chromatography method with ultra-violet detection (HPLC-UV) for the quantitative determination of EFV in plasma was developed and successfully validated according to international standards with good reproducibility, accuracy, recovery, linear response and requisite sensitivity. The preparation of the plasma samples for analysis was effected by using a simple and rapid precipitation method, and the mobile phase consisted of readily available solvents. EFV in plasma samples was found to be stable under the relevant storage conditions studied. The oral dose of AP, administered as a freshly prepared traditional decoction, was standardised based on the hypoxoside content, and the quality of all the AP decoctions was analysed immediately prior to administration, using a validated HPLC-UV method. A single dose, two-phase sequential study was conducted over a period of 31 days in 10 healthy volunteers. The clinical study was approved by the Rhodes University Ethical Standards Committee, and all the participants agreed to the conditions of the study by giving their informed consent. On day 1 of the study, human subjects were administered a 600 mg EFV tablet and blood samples were collected before dosing and at various intervals over a period of 48 hr post dosing. From day 16, a traditionally prepared AP decoction was administered daily at a standardized dose of 15 mg/kg/day per subject until day 30. On day 29, volunteers were administered a single 600 mg dose of EFV as was done on day 1. Plasma samples were harvested immediately after blood sample collection and frozen at -80 ºC until assayed. Geometric mean ratios of relevant pharmacokinetic parameters, Cmax (maximum plasma concentration achieved following dosing) and AUC0-48 (area under the curve of a plot of drug plasma concentrations versus time representing the extent of absorption) of EFV before and after co-administration of 14 successive daily doses of AP were compared and evaluated to determine whether an interaction had occurred. All subjects completed the study and the geometric mean ratios of Cmax and AUC0-48 were 97.30 and 102.82 with corresponding 90% confidence intervals (CIs) of 78.81-120.14% and 89.04-118.80%, respectively. Whereas the acceptance criteria for the ratios of the AUCs fell within the preset 90% CIs indicating no interaction, the Cmax ratios fell outside the limits. Although the protocol was developed in accordance with the United States of America Food & Drug Administration’s Guidance for Drug Interactions, a priori stating that both criteria need to fall within the acceptance limits to indicate no interaction, an argument is presented to waive the Cmax requirement for the declaration of an interaction. As a result, the pharmacokinetic data generated during this study indicated that the effect of AP on the pharmacokinetics of EFV is not clinically significant. Hence, co-administration of AP is unlikely to affect the clinical use of EFV. In summary the objectives of this project were: 1. To develop and validate a suitable HPLC-UV method for the quantitative determination of EFV in plasma. 2. To perform a mini-validation of the determination of hypoxoside for use as a marker in the quality control and standardisation of AP decoctions. 3. To conduct a clinical interaction study in order to determine whether AP affects the pharmacokinetics of EFV following concurrent administration. 4. To apply the validated HPLC-UV method to determine plasma concentrations of EFV in plasma of human subjects. 5. To use appropriate statistical methods and treatments such as a non-compartmental pharmacokinetic analysis to determine the occurrence of an interaction.
- Full Text:
- Date Issued: 2009
- Authors: Mogatle, Seloi
- Date: 2009
- Subjects: Potatoes -- Africa Potatoes -- Therapeutic use Medicinal plants Traditional medicine AIDS (Disease) -- Treatment HIV infections -- Drug therapy Drug interactions Antiretroviral agents Pharmacokinetics Hypoxidaceae -- Therapeutic use High performance liquid chromatography
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3773 , http://hdl.handle.net/10962/d1003251
- Description: African Potato (Hypoxis hemerocallidea), (AP) is an African traditional medicine (TM) that is commonly used for various nutritional/medicinal purposes and also by people infected with the human immuno deficiency virus HIV and AIDS patients as an immune booster. The use of AP has also been recommended by the former Minister of Health of South Africa for use by HIV positive people. The main phytochemical component of AP is a norlignan glucoside, hypoxoside, and other relatively minor components have also been reported. A recent in vitro study reported the effects of AP extracts, hypoxoside and rooperol (the metabolite of hypoxoside) on human metabolic enzymes such as the cytochrome P450 (CYP450) group of enzymes and also on the transporter protein, p-glycoprotein (P-gp). This research focussed on investigating the clinical significance of those in vitro effects on the pharmacokinetics of efavirenz (EFV) in humans. EFV was chosen as the substrate drug because it is in first-line regimen of treatment of HIV/AIDS in South Africa, and also has been reported to be a substrate for the specific CYP isozymes, 3A4 and 2B6, in common with APs metabolic involvement with 3A4. A high performance liquid chromatography method with ultra-violet detection (HPLC-UV) for the quantitative determination of EFV in plasma was developed and successfully validated according to international standards with good reproducibility, accuracy, recovery, linear response and requisite sensitivity. The preparation of the plasma samples for analysis was effected by using a simple and rapid precipitation method, and the mobile phase consisted of readily available solvents. EFV in plasma samples was found to be stable under the relevant storage conditions studied. The oral dose of AP, administered as a freshly prepared traditional decoction, was standardised based on the hypoxoside content, and the quality of all the AP decoctions was analysed immediately prior to administration, using a validated HPLC-UV method. A single dose, two-phase sequential study was conducted over a period of 31 days in 10 healthy volunteers. The clinical study was approved by the Rhodes University Ethical Standards Committee, and all the participants agreed to the conditions of the study by giving their informed consent. On day 1 of the study, human subjects were administered a 600 mg EFV tablet and blood samples were collected before dosing and at various intervals over a period of 48 hr post dosing. From day 16, a traditionally prepared AP decoction was administered daily at a standardized dose of 15 mg/kg/day per subject until day 30. On day 29, volunteers were administered a single 600 mg dose of EFV as was done on day 1. Plasma samples were harvested immediately after blood sample collection and frozen at -80 ºC until assayed. Geometric mean ratios of relevant pharmacokinetic parameters, Cmax (maximum plasma concentration achieved following dosing) and AUC0-48 (area under the curve of a plot of drug plasma concentrations versus time representing the extent of absorption) of EFV before and after co-administration of 14 successive daily doses of AP were compared and evaluated to determine whether an interaction had occurred. All subjects completed the study and the geometric mean ratios of Cmax and AUC0-48 were 97.30 and 102.82 with corresponding 90% confidence intervals (CIs) of 78.81-120.14% and 89.04-118.80%, respectively. Whereas the acceptance criteria for the ratios of the AUCs fell within the preset 90% CIs indicating no interaction, the Cmax ratios fell outside the limits. Although the protocol was developed in accordance with the United States of America Food & Drug Administration’s Guidance for Drug Interactions, a priori stating that both criteria need to fall within the acceptance limits to indicate no interaction, an argument is presented to waive the Cmax requirement for the declaration of an interaction. As a result, the pharmacokinetic data generated during this study indicated that the effect of AP on the pharmacokinetics of EFV is not clinically significant. Hence, co-administration of AP is unlikely to affect the clinical use of EFV. In summary the objectives of this project were: 1. To develop and validate a suitable HPLC-UV method for the quantitative determination of EFV in plasma. 2. To perform a mini-validation of the determination of hypoxoside for use as a marker in the quality control and standardisation of AP decoctions. 3. To conduct a clinical interaction study in order to determine whether AP affects the pharmacokinetics of EFV following concurrent administration. 4. To apply the validated HPLC-UV method to determine plasma concentrations of EFV in plasma of human subjects. 5. To use appropriate statistical methods and treatments such as a non-compartmental pharmacokinetic analysis to determine the occurrence of an interaction.
- Full Text:
- Date Issued: 2009
Uphononongo lwemiba yentlalo inkcubeko noburharha ephembelela ababhali kuthiyo lwabalinganiswa kwiincwadi zedrama zesiXhosa ezichongiweyo
- Authors: Kapa, Nompumelelo
- Date: 2018
- Subjects: Characters and characteristics in literature Xhosa drama
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/8440 , vital:32795
- Description: Olu phando luzakuqwalasela iimeko abathi bazilandele ababhali xa bathiya abalinganiswa phantsi kweemeko zenkcubeko noburharha, kwakunye nokubaluleka kwalo gabalala. Oku kuzakwenziwa kuboniswa nenxaxheba elithi liyidlale ebomini. Kuza kuhlalutywa ezi ncwadi zilandelayo:Amaza ngokubhalwe ngu-Z.S. Qangule, Buzani kuBawo ngu-W.K.Tamsanqa Akwaba ng-T.Ntwana, Iziphumo Zodendo ngu-L.E.Menze, Emgxobhozweni ngu-B.B.Mkonto, Yeha Mfazi Obulala Indoda ngu-L.L.Ngewu, Hay’Ukuzenza ngu-C.F.Jaji. Kwezi ncwadi kuzakuhlalutywa iimeko ezilandelwa ngababhali xa bethiya abalinganiswa kunye nendima edlalwa ligama lo mlinganiswa ngamnye ebalini, oku kuza kubonisa indlela ekuthiywa ngayo ekuhlaleni kwakunye nokubaluleka kwegama kumnini lo. Isahluko sokuqala sizakunika amagqabantshintshi ngolu phando. Esi sahlukosiqulathe oku kulandelayo:Ingabula zigcawu ngophando• Imvelaphi ngentsusa yokuthiywa kwegama• Iinjongo zolu phando• Okunye okufunyenweyo kolu phando• Indlela oluza kuqhutywa ngayo olu phando• Iingxaki zolu phando• Imibuzo yolu phando• Amagqabantshintshi ngezahluko zoluphando Isahluko sesibini siqwalasele ithiyori ezakuthi isetyenziswe kolu phando . Oku kwenziwa ngokuthi kuqwalaselwe ukuba bathini abanye ababhali ngothiyo. Isahluko sesithathu luphononongo lwabalinganiswa kwincwadi nganye kwezichongiweyo, kulandelwa inkcubeko neemeko zasekuhlaleni . Isahluko sesine sijonge ubugcisa boburharha obulandelwe ngababhali xa bathiya abalinganiswa, kwiincwadi ezichongiweyo, kwakunye nendima ethi edlalwe ngabalinganiswa ebalini. Isahluko sesihlanu nesisesokugqibela, siveza ulwazi oluthe lwafumaneka kuthiyo ngqo, luthelekisa nothiyo ezincwadini,sishwankathela iziphumo zophando.
- Full Text:
- Date Issued: 2018
- Authors: Kapa, Nompumelelo
- Date: 2018
- Subjects: Characters and characteristics in literature Xhosa drama
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/8440 , vital:32795
- Description: Olu phando luzakuqwalasela iimeko abathi bazilandele ababhali xa bathiya abalinganiswa phantsi kweemeko zenkcubeko noburharha, kwakunye nokubaluleka kwalo gabalala. Oku kuzakwenziwa kuboniswa nenxaxheba elithi liyidlale ebomini. Kuza kuhlalutywa ezi ncwadi zilandelayo:Amaza ngokubhalwe ngu-Z.S. Qangule, Buzani kuBawo ngu-W.K.Tamsanqa Akwaba ng-T.Ntwana, Iziphumo Zodendo ngu-L.E.Menze, Emgxobhozweni ngu-B.B.Mkonto, Yeha Mfazi Obulala Indoda ngu-L.L.Ngewu, Hay’Ukuzenza ngu-C.F.Jaji. Kwezi ncwadi kuzakuhlalutywa iimeko ezilandelwa ngababhali xa bethiya abalinganiswa kunye nendima edlalwa ligama lo mlinganiswa ngamnye ebalini, oku kuza kubonisa indlela ekuthiywa ngayo ekuhlaleni kwakunye nokubaluleka kwegama kumnini lo. Isahluko sokuqala sizakunika amagqabantshintshi ngolu phando. Esi sahlukosiqulathe oku kulandelayo:Ingabula zigcawu ngophando• Imvelaphi ngentsusa yokuthiywa kwegama• Iinjongo zolu phando• Okunye okufunyenweyo kolu phando• Indlela oluza kuqhutywa ngayo olu phando• Iingxaki zolu phando• Imibuzo yolu phando• Amagqabantshintshi ngezahluko zoluphando Isahluko sesibini siqwalasele ithiyori ezakuthi isetyenziswe kolu phando . Oku kwenziwa ngokuthi kuqwalaselwe ukuba bathini abanye ababhali ngothiyo. Isahluko sesithathu luphononongo lwabalinganiswa kwincwadi nganye kwezichongiweyo, kulandelwa inkcubeko neemeko zasekuhlaleni . Isahluko sesine sijonge ubugcisa boburharha obulandelwe ngababhali xa bathiya abalinganiswa, kwiincwadi ezichongiweyo, kwakunye nendima ethi edlalwe ngabalinganiswa ebalini. Isahluko sesihlanu nesisesokugqibela, siveza ulwazi oluthe lwafumaneka kuthiyo ngqo, luthelekisa nothiyo ezincwadini,sishwankathela iziphumo zophando.
- Full Text:
- Date Issued: 2018
Synthesis of chiral ketopinic acid-derived catalysts and their evaluation in asymmetric transformations
- Authors: Hassan, Yusuf
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/550 , vital:19969
- Description: Four new (+)-ketopinic acid-derived Mn(III) complexes, three of which possess pseudo C2- symmetry, were synthesised as chiral catalyst candidates. The ligands were prepared by refluxing (+)-ketopinic acid with ethane-1,2-diamine, the resolved (R,R)- and (S,S)-1,2-diaminocyclohexanes, and 1,2-diaminobenzene in chloroform. Treatment of the ligands with manganese(II) acetate tetrahydrate in refluxing ethanol afforded the respective complexes as brown amorphous powders. Characterisation of the ligands and the corresponding complexes was achieved using 1-D and 2-D NMR, IR spectroscopy, and elemental analysis. Various homogeneous asymmetric transformations, were investigated using these four complexes, viz., aldol, and Baylis-Hillman reactions, aza-Michael addition of piperidine to the Baylis-Hillman adducts, epoxidation, and ketone and imine reduction. Asymmetric aldol reactions of benzaldehyde with the aryl ketones, acetophenone, propiophenone, -tetralone, 4-nitroacetophenone, and 4-methoxyacetophenone, conducted in the presence of 10 mole % of the chiral catalysts, afforded enantioselectivities of up to 99% e.e. Asymmetric Baylis-Hillman reactions of methyl- and tert-butyl acrylates with pyridine-2- carbaldehyde, 6-methylpyridine-2-carbaldehyde, 5-chlorosalicylaldehyde, benzaldehyde, 4-chlorobenzaldehyde, and 2-nitrobenzaldehyde were conducted in the presence of catalyst 139 (10 mole %) to afford enantioselectivities of up to 44% e.e. Aza-Michael addition of piperidine to racemic Baylis- Hillman adducts in the presence of the catalyst 139 (10 mole %) was found to proceed with diastereoselectivities of up to 91% d.e. Asymmetric epoxidation of trans-methyl styrene, styrene, trans-stilbene, cis-stilbene, and indene, using a 5 mole % chiral catalyst loading and m-CPBA as the oxygen source, gave enantioselectivities of up to 32 % e.e. Asymmetric reductions of acetophenone, 3-chloropropiophenone, 4-hydroxyacetophenone, -tetralone, and 2-hydroxy-1-acetonapthone were investigated using NaBH4 as the reducing agent and a 10 mole % loading of the chiral catalysts. A stereoselectivity of 68% e.e. was obtained in the reduction of acetophenone, but attempts to reduce the selected imines to the corresponding chiral amines proved to be unsuccessful — even in the absence of the catalysts. It thus became apparent that the catalytic version of the reaction was not feasible.
- Full Text:
- Date Issued: 2016
- Authors: Hassan, Yusuf
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/550 , vital:19969
- Description: Four new (+)-ketopinic acid-derived Mn(III) complexes, three of which possess pseudo C2- symmetry, were synthesised as chiral catalyst candidates. The ligands were prepared by refluxing (+)-ketopinic acid with ethane-1,2-diamine, the resolved (R,R)- and (S,S)-1,2-diaminocyclohexanes, and 1,2-diaminobenzene in chloroform. Treatment of the ligands with manganese(II) acetate tetrahydrate in refluxing ethanol afforded the respective complexes as brown amorphous powders. Characterisation of the ligands and the corresponding complexes was achieved using 1-D and 2-D NMR, IR spectroscopy, and elemental analysis. Various homogeneous asymmetric transformations, were investigated using these four complexes, viz., aldol, and Baylis-Hillman reactions, aza-Michael addition of piperidine to the Baylis-Hillman adducts, epoxidation, and ketone and imine reduction. Asymmetric aldol reactions of benzaldehyde with the aryl ketones, acetophenone, propiophenone, -tetralone, 4-nitroacetophenone, and 4-methoxyacetophenone, conducted in the presence of 10 mole % of the chiral catalysts, afforded enantioselectivities of up to 99% e.e. Asymmetric Baylis-Hillman reactions of methyl- and tert-butyl acrylates with pyridine-2- carbaldehyde, 6-methylpyridine-2-carbaldehyde, 5-chlorosalicylaldehyde, benzaldehyde, 4-chlorobenzaldehyde, and 2-nitrobenzaldehyde were conducted in the presence of catalyst 139 (10 mole %) to afford enantioselectivities of up to 44% e.e. Aza-Michael addition of piperidine to racemic Baylis- Hillman adducts in the presence of the catalyst 139 (10 mole %) was found to proceed with diastereoselectivities of up to 91% d.e. Asymmetric epoxidation of trans-methyl styrene, styrene, trans-stilbene, cis-stilbene, and indene, using a 5 mole % chiral catalyst loading and m-CPBA as the oxygen source, gave enantioselectivities of up to 32 % e.e. Asymmetric reductions of acetophenone, 3-chloropropiophenone, 4-hydroxyacetophenone, -tetralone, and 2-hydroxy-1-acetonapthone were investigated using NaBH4 as the reducing agent and a 10 mole % loading of the chiral catalysts. A stereoselectivity of 68% e.e. was obtained in the reduction of acetophenone, but attempts to reduce the selected imines to the corresponding chiral amines proved to be unsuccessful — even in the absence of the catalysts. It thus became apparent that the catalytic version of the reaction was not feasible.
- Full Text:
- Date Issued: 2016
Development of a novel, quantitative assay for determining the rate of activity of antimalarial drugs
- Authors: Khan, Tasmiyah
- Date: 2013
- Subjects: Assay , ATP , Antimalarials -- Therapeutic use Malaria Malaria -- Drug therapy Adenosine triphosphate Luciferases Plasmodium falciparum
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3884 , http://hdl.handle.net/10962/d1001618
- Description: Malaria, caused by an intracellular Plasmodium parasite, remains a devastating disease, having claimed approximately 655 000 lives worldwide in 2010. The Medicines for Malaria Venture suggests a "single-dose radical cure" as the ideal malaria treatment since rapid clearance of blood-stage parasites and symptom relief improves patient compliance and limits drug resistance. Thus, novel antimalarials should be rapid-acting and assessing their rate of activity is critical to drug discovery. Traditional evaluation of this rate by morphological assessments is flawed by highly subjective, operator-specific interpretations, mainly due to heterogeneous parasite morphology under routine culture conditions. This study aimed to develop an alternative, quantitative assay. Energy is vital for the growth and maintenance of all living organisms. Commercially available kits allow rapid quantification of the cell's energy currency, ATP. Therefore, quantification of parasite ATP shows potential for diagnosing abnormal parasite metabolism and the kinetics of drug action. In this study, a rapid protocol for detecting ATP in Plasmodium falciparum parasites using a luminescence-based kit was developed and optimised. Furthermore, luciferase-expressing transgenic parasites, in which luciferase activity is detected using a similar kit, were acquired. The utility of both methods for evaluating the rate of drug-induced stress was explored using antimalarials with varying modes of action and, presumably, rates of activity. Results showed that parasite ATP remained unchanged, increased or decreased during drug exposure. Morphological examinations by light microscopy and a Recovery assay, aided interpretation of the drug-induced changes in parasite ATP. These investigations suggested that unchanged parasite ATP levels reflect poor drug action, increased ATP levels indicate a stress response and partially compromised viability, while significantly reduced ATP reflects severely compromised viability. Concerning the Luciferase assay, parasite luciferase activity decreased during drug exposure, even in the presence of proteasome inhibitors. Changes in parasite ATP and luciferase activity occurred at rates which suggested that chloroquine is slow-acting, mefloquine has a moderate rate of activity and artemisinin is rapid-acting. These findings are compatible with the expected rates of activity of these established antimalarials. Hence, measurement of parasite ATP and/or luciferase activity may support assessments of parasite health and the kinetics of antimalarial action during drug discovery
- Full Text:
- Date Issued: 2013
- Authors: Khan, Tasmiyah
- Date: 2013
- Subjects: Assay , ATP , Antimalarials -- Therapeutic use Malaria Malaria -- Drug therapy Adenosine triphosphate Luciferases Plasmodium falciparum
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3884 , http://hdl.handle.net/10962/d1001618
- Description: Malaria, caused by an intracellular Plasmodium parasite, remains a devastating disease, having claimed approximately 655 000 lives worldwide in 2010. The Medicines for Malaria Venture suggests a "single-dose radical cure" as the ideal malaria treatment since rapid clearance of blood-stage parasites and symptom relief improves patient compliance and limits drug resistance. Thus, novel antimalarials should be rapid-acting and assessing their rate of activity is critical to drug discovery. Traditional evaluation of this rate by morphological assessments is flawed by highly subjective, operator-specific interpretations, mainly due to heterogeneous parasite morphology under routine culture conditions. This study aimed to develop an alternative, quantitative assay. Energy is vital for the growth and maintenance of all living organisms. Commercially available kits allow rapid quantification of the cell's energy currency, ATP. Therefore, quantification of parasite ATP shows potential for diagnosing abnormal parasite metabolism and the kinetics of drug action. In this study, a rapid protocol for detecting ATP in Plasmodium falciparum parasites using a luminescence-based kit was developed and optimised. Furthermore, luciferase-expressing transgenic parasites, in which luciferase activity is detected using a similar kit, were acquired. The utility of both methods for evaluating the rate of drug-induced stress was explored using antimalarials with varying modes of action and, presumably, rates of activity. Results showed that parasite ATP remained unchanged, increased or decreased during drug exposure. Morphological examinations by light microscopy and a Recovery assay, aided interpretation of the drug-induced changes in parasite ATP. These investigations suggested that unchanged parasite ATP levels reflect poor drug action, increased ATP levels indicate a stress response and partially compromised viability, while significantly reduced ATP reflects severely compromised viability. Concerning the Luciferase assay, parasite luciferase activity decreased during drug exposure, even in the presence of proteasome inhibitors. Changes in parasite ATP and luciferase activity occurred at rates which suggested that chloroquine is slow-acting, mefloquine has a moderate rate of activity and artemisinin is rapid-acting. These findings are compatible with the expected rates of activity of these established antimalarials. Hence, measurement of parasite ATP and/or luciferase activity may support assessments of parasite health and the kinetics of antimalarial action during drug discovery
- Full Text:
- Date Issued: 2013
Investigating an environmental education curriculum to a developing society's needs: a case study of the programme offered at the Pilanesberg National Park, Bophuthatswana
- Authors: Johnson, Steven Robert
- Date: 1994
- Subjects: Environmental education Environmental education -- Curricula -- South Africa -- Bophuthatswana Environmental education -- Curricula -- Case studies Pilanesberg National Park (South Africa)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1585 , http://hdl.handle.net/10962/d1003467
- Description: The Environmental Education programme offered at the Gold Fields Environmental Education Centre (GFEE Centre) in the Pilanesberg National Park, Bophuthatswana, was initiated in response to requests from schools in Bophuthatswana to visit game reserves as 'syllabus related school activities'. Evaluative research into the GFEE Centre programme by an external researcher indicated that the learning experiences largely concentrated on cognitive development, and neglected to influence affective and psychomotor development. After a number of adaptations to the programme, which emphasised a more child-centred approach it was realised that little was known about the background and learning needs of the predominantly BaTswana school children. It was felt by the researcher that the learning activities provided at the GFEE Centre could also possibly be biased by a Western, scientific orientation which possibly lacked relevance to the cultural backgrounds of the pupils. The researcher used an action research approach in a number of workshops with a purposive sample of BaTswana primary school teachers, to gather data. The teachers were encouraged to critically reflect on the background and learning-needs of BaTswana children, with specific regard to environmental issues and worldviews. The information provided by the teachers' reflective deliberations and a seperate research project with school children, indicated that primary school children in Bophuthatswana tend to follow accepted human development patterns in their perceptions of the environment. The influence of either a predominantly rural or urban upbringing during a child's early formative years was considered by the teachers to be significant in determining worldviews, and culture was considered to have an influence on children's learning processes. Their beliefs and experiences were used by them in generating suggestions to correct the GFEE Centre programme. The teachers' also highlighted the fact that there were a number of socio-cultural and institutional issues which influenced the effectiveness of the GFEE Centre programme.
- Full Text:
- Date Issued: 1994
- Authors: Johnson, Steven Robert
- Date: 1994
- Subjects: Environmental education Environmental education -- Curricula -- South Africa -- Bophuthatswana Environmental education -- Curricula -- Case studies Pilanesberg National Park (South Africa)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1585 , http://hdl.handle.net/10962/d1003467
- Description: The Environmental Education programme offered at the Gold Fields Environmental Education Centre (GFEE Centre) in the Pilanesberg National Park, Bophuthatswana, was initiated in response to requests from schools in Bophuthatswana to visit game reserves as 'syllabus related school activities'. Evaluative research into the GFEE Centre programme by an external researcher indicated that the learning experiences largely concentrated on cognitive development, and neglected to influence affective and psychomotor development. After a number of adaptations to the programme, which emphasised a more child-centred approach it was realised that little was known about the background and learning needs of the predominantly BaTswana school children. It was felt by the researcher that the learning activities provided at the GFEE Centre could also possibly be biased by a Western, scientific orientation which possibly lacked relevance to the cultural backgrounds of the pupils. The researcher used an action research approach in a number of workshops with a purposive sample of BaTswana primary school teachers, to gather data. The teachers were encouraged to critically reflect on the background and learning-needs of BaTswana children, with specific regard to environmental issues and worldviews. The information provided by the teachers' reflective deliberations and a seperate research project with school children, indicated that primary school children in Bophuthatswana tend to follow accepted human development patterns in their perceptions of the environment. The influence of either a predominantly rural or urban upbringing during a child's early formative years was considered by the teachers to be significant in determining worldviews, and culture was considered to have an influence on children's learning processes. Their beliefs and experiences were used by them in generating suggestions to correct the GFEE Centre programme. The teachers' also highlighted the fact that there were a number of socio-cultural and institutional issues which influenced the effectiveness of the GFEE Centre programme.
- Full Text:
- Date Issued: 1994
Bioaccumulation of heavy metals by the yeast S. cerevisiae and the bioremediation of industrial waste water
- Authors: Stoll, Anita
- Date: 1997
- Subjects: Saccharomyces cerevisiae Yeast fungi -- Biotechnology Metal ions Bioremediation Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4015 , http://hdl.handle.net/10962/d1004075
- Description: Water is an essential element in all aspects of life and is vital for both domestic and industrial purposes regarding both the quality and quantity thereof. Similar to many other drought stricken countries, South Africa requires water for the socio-economic growth of the country, yet is faced with the problem of maintaining the quality of its drinking water as well as protecting the dwindling supplies. In an attempt to prevent the deterioration of South African water supplies the treatment, purification and recycling of industrial and mining waste water has recently become of prime importance. Many industrial and mining waste waters contain heavy metals in toxic quantities. The conventional processes that have been used till recently to address this problem, are often expensive or contain chemical agents which compound the environmental problem. As an alternative biological methods of metal accumulation appear to offer an economic and efficient alternative to these methods. An advantage to the South African scenario is the commercial production of the yeast, S. cerevisiae as a readily inexpensive by-product from some fermentation industries, Yeast cells, and in particular S. cerevisiae have proven to be capable of accumulating heavy metals, and therefore exhibit potential application in the bioremediation of waste water. The aim of this project was twofold. The initial part of this work attempted to define the mechanisms of metal accumulation by the yeast cells and cellular components. The information obtained from these initial studies provided a data base required for the development of a bioremediation system. Initial contact with the metal ions occurs at the wall interface of the yeast cell. Metal accumulation appears to be a function of all the cell wall components. The isolated cell wall components are better metal chelators then the intact cell walls. An apparent affinity series of mannan > chitin> glucan > intact cell walls exists. However, these components differ in their affinities for metal ions. Storage of metal ions within the cell occurs predominantly in the vacuole. The present study concluded that metal accumulation by the vacuole could be related to size. Metal accumulation occurred in the order of Cu2+ > Co2+ > Cd2+ with a corresponding decrease in atomic radii of Cd2+ > C02+ > Cu2+. Vacuolar ion deposition occurs at an early stage during the internalization of metal ions within the yeast cells. At the onset of vacuolar saturation, depositions of metal ions as granules within the cytosol occurs. In the presence of heavy metal cations viable yeast cells can be shown to exhibit two types of cellular responses. Uptake of Cu2+ and Cd2+ causes the loss of intracellular physiological cations from within the yeast cell. In comparison, uptake of Co2+ into the cell does not have this effect. All three heavy metal cations initiate plasma cell membrane permeability, thus the Cu2+ and Cd2+ induced loss of the intracellular cations, occurs. ~ a result of ion-exchange mechanisms and not due to cation leakage brought about by membrane permeabilization. Uptake of heavy metals by viable yeasts appears to be generally non-selective though the amount of metals accumulated are largely affected by the ratio of ambient metal concentration to biomass quantity. In addition, the energy dependent nature of internalization necessitates the availability of an external energy source for metal uptake by viable yeast cells. For these reasons metal removal from industrial waste water was investigated using non-viable biomass. By immobilizing the yeast cells additional mechanical integrity and stability was conferred apon the biomass. The three types of biomass preparations developed in this study, viz. polyvinyl alcohol (PV A) Na-alginate, PV A Na-orthophosphate and alkali treated polyethylenimine (PEI):glutaraldehyde (GA) biomass pellets, all fulfilled the necessary physical requirements. However, the superior metal accumulating properties of the PEI:GA biomass determined its selection as a biosorbent for bioremediation purposes. Biosorption of heavy metals by PEI:GA biomass is of a competitive nature, with the amount of metal accumulated influenced by the availability of the metal ions. This availability is largely determined by the solution pH. At low pH values the affinity of the biomass for metals decreases, whilst enhanced metal biosorption occurs at higher pHs, ego pH 4.5 - 6.0. PEI:GA biomass pellets can be implemented -as a biosorbent for the bi9remediaiton of high concentration, low-volume metal containing industrial waste. Several options regarding the bioremediation system are available. Depending on the concentration of the metals in the effluent, the bioremediation process can either be used independently or as part of a biphasic remediation system for the treatment of waste water. Initial phase chemical modification may be required, whilst two types of biological systems can be implemented as 'part of the second phase. The PEI:GA biomass can either be contained within continuous-flow fixed bed tanks or continuous-flow stirred bioreactor tanks. Due to the simplicity of the process and the ease with which scale-up is facilitated, the second type of system shows greater application potential for the treatment of this type of industrial waste water than the fixed-bed systems.
- Full Text:
- Date Issued: 1997
- Authors: Stoll, Anita
- Date: 1997
- Subjects: Saccharomyces cerevisiae Yeast fungi -- Biotechnology Metal ions Bioremediation Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4015 , http://hdl.handle.net/10962/d1004075
- Description: Water is an essential element in all aspects of life and is vital for both domestic and industrial purposes regarding both the quality and quantity thereof. Similar to many other drought stricken countries, South Africa requires water for the socio-economic growth of the country, yet is faced with the problem of maintaining the quality of its drinking water as well as protecting the dwindling supplies. In an attempt to prevent the deterioration of South African water supplies the treatment, purification and recycling of industrial and mining waste water has recently become of prime importance. Many industrial and mining waste waters contain heavy metals in toxic quantities. The conventional processes that have been used till recently to address this problem, are often expensive or contain chemical agents which compound the environmental problem. As an alternative biological methods of metal accumulation appear to offer an economic and efficient alternative to these methods. An advantage to the South African scenario is the commercial production of the yeast, S. cerevisiae as a readily inexpensive by-product from some fermentation industries, Yeast cells, and in particular S. cerevisiae have proven to be capable of accumulating heavy metals, and therefore exhibit potential application in the bioremediation of waste water. The aim of this project was twofold. The initial part of this work attempted to define the mechanisms of metal accumulation by the yeast cells and cellular components. The information obtained from these initial studies provided a data base required for the development of a bioremediation system. Initial contact with the metal ions occurs at the wall interface of the yeast cell. Metal accumulation appears to be a function of all the cell wall components. The isolated cell wall components are better metal chelators then the intact cell walls. An apparent affinity series of mannan > chitin> glucan > intact cell walls exists. However, these components differ in their affinities for metal ions. Storage of metal ions within the cell occurs predominantly in the vacuole. The present study concluded that metal accumulation by the vacuole could be related to size. Metal accumulation occurred in the order of Cu2+ > Co2+ > Cd2+ with a corresponding decrease in atomic radii of Cd2+ > C02+ > Cu2+. Vacuolar ion deposition occurs at an early stage during the internalization of metal ions within the yeast cells. At the onset of vacuolar saturation, depositions of metal ions as granules within the cytosol occurs. In the presence of heavy metal cations viable yeast cells can be shown to exhibit two types of cellular responses. Uptake of Cu2+ and Cd2+ causes the loss of intracellular physiological cations from within the yeast cell. In comparison, uptake of Co2+ into the cell does not have this effect. All three heavy metal cations initiate plasma cell membrane permeability, thus the Cu2+ and Cd2+ induced loss of the intracellular cations, occurs. ~ a result of ion-exchange mechanisms and not due to cation leakage brought about by membrane permeabilization. Uptake of heavy metals by viable yeasts appears to be generally non-selective though the amount of metals accumulated are largely affected by the ratio of ambient metal concentration to biomass quantity. In addition, the energy dependent nature of internalization necessitates the availability of an external energy source for metal uptake by viable yeast cells. For these reasons metal removal from industrial waste water was investigated using non-viable biomass. By immobilizing the yeast cells additional mechanical integrity and stability was conferred apon the biomass. The three types of biomass preparations developed in this study, viz. polyvinyl alcohol (PV A) Na-alginate, PV A Na-orthophosphate and alkali treated polyethylenimine (PEI):glutaraldehyde (GA) biomass pellets, all fulfilled the necessary physical requirements. However, the superior metal accumulating properties of the PEI:GA biomass determined its selection as a biosorbent for bioremediation purposes. Biosorption of heavy metals by PEI:GA biomass is of a competitive nature, with the amount of metal accumulated influenced by the availability of the metal ions. This availability is largely determined by the solution pH. At low pH values the affinity of the biomass for metals decreases, whilst enhanced metal biosorption occurs at higher pHs, ego pH 4.5 - 6.0. PEI:GA biomass pellets can be implemented -as a biosorbent for the bi9remediaiton of high concentration, low-volume metal containing industrial waste. Several options regarding the bioremediation system are available. Depending on the concentration of the metals in the effluent, the bioremediation process can either be used independently or as part of a biphasic remediation system for the treatment of waste water. Initial phase chemical modification may be required, whilst two types of biological systems can be implemented as 'part of the second phase. The PEI:GA biomass can either be contained within continuous-flow fixed bed tanks or continuous-flow stirred bioreactor tanks. Due to the simplicity of the process and the ease with which scale-up is facilitated, the second type of system shows greater application potential for the treatment of this type of industrial waste water than the fixed-bed systems.
- Full Text:
- Date Issued: 1997
Polymerized serum albumin beads for use as slow-release adjuvants
- Martin, Michelle Elizabeth Denny
- Authors: Martin, Michelle Elizabeth Denny
- Date: 1988
- Subjects: Serum albumin , Antigens , Vaccines
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3879 , http://hdl.handle.net/10962/d1001613
- Description: Experimental vaccines have been made by covalently bonding virus particles into polymerized rabbit serum albumin beads. Using Nodamura virus as a model antigen, these model vaccines induced specific humoral antibody production, comparable with that achieved using Freund's adjuvants. Virus specific antibodies were also induced when Nodamura virus was covalently attached to the bead surface using different crosslinkers. However, when poliovirus type 2 (Sabin strain) was polymerized into beads, the levels of neutralizing antibodies were insignificant compared with control aqueous vaccines. The synthetic immunostimulator, muramyl dipeptide, was included with bead vaccines in an attempt to potentiate the immune response. Immunostimulation is achieved by a slow release of antigen coinciding with the gradual breakdown of bead structure.
- Full Text:
- Date Issued: 1988
- Authors: Martin, Michelle Elizabeth Denny
- Date: 1988
- Subjects: Serum albumin , Antigens , Vaccines
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3879 , http://hdl.handle.net/10962/d1001613
- Description: Experimental vaccines have been made by covalently bonding virus particles into polymerized rabbit serum albumin beads. Using Nodamura virus as a model antigen, these model vaccines induced specific humoral antibody production, comparable with that achieved using Freund's adjuvants. Virus specific antibodies were also induced when Nodamura virus was covalently attached to the bead surface using different crosslinkers. However, when poliovirus type 2 (Sabin strain) was polymerized into beads, the levels of neutralizing antibodies were insignificant compared with control aqueous vaccines. The synthetic immunostimulator, muramyl dipeptide, was included with bead vaccines in an attempt to potentiate the immune response. Immunostimulation is achieved by a slow release of antigen coinciding with the gradual breakdown of bead structure.
- Full Text:
- Date Issued: 1988
FRAME: frame routing and manipulation engine
- Authors: Pennefather, Sean Niel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3608 , vital:20529
- Description: This research reports on the design and implementation of FRAME: an embedded hardware network processing platform designed to perform network frame manipulation and monitoring. This is possible at line speeds compliant with the IEEE 802.3 Ethernet standard. The system provides frame manipulation functionality to aid in the development and implementation of network testing environments. Platform cost and ease of use are both considered during design resulting in fabrication of hardware and the development of Link, a Domain Specific Language used to create custom applications that are compatible with the platform. Functionality of the resulting platform is shown through conformance testing of designed modules and application examples. Throughput testing showed that the peak throughput achievable by the platform is limited to 86.4 Mbit/s, comparable to commodity 100 Mbit hardware and the total cost of the prototype platform ranged between $220 and $254.
- Full Text:
- Date Issued: 2016
- Authors: Pennefather, Sean Niel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3608 , vital:20529
- Description: This research reports on the design and implementation of FRAME: an embedded hardware network processing platform designed to perform network frame manipulation and monitoring. This is possible at line speeds compliant with the IEEE 802.3 Ethernet standard. The system provides frame manipulation functionality to aid in the development and implementation of network testing environments. Platform cost and ease of use are both considered during design resulting in fabrication of hardware and the development of Link, a Domain Specific Language used to create custom applications that are compatible with the platform. Functionality of the resulting platform is shown through conformance testing of designed modules and application examples. Throughput testing showed that the peak throughput achievable by the platform is limited to 86.4 Mbit/s, comparable to commodity 100 Mbit hardware and the total cost of the prototype platform ranged between $220 and $254.
- Full Text:
- Date Issued: 2016
The contribution of non-timber forest products to rural livelihoods and their price determination in different agro-ecological zones of South Africa
- Authors: Mugido, Worship
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5176 , vital:20783
- Description: A large number of studies have been conducted on the contribution of different types of non-timber forest products (NTFPs) to rural livelihoods. However, not many of these have considered the context in which these contributions are made, especially agro-ecological potential. Similarly, there are few studies that focus on the price setting of NTFPs in different settings as most are based on a single or relatively few sites. Thus, there is no indication of the prevalence of the different factors within a uniform macro context, nor how they might vary between different types of NTFPs. Therefore, the aim of this thesis was to establish the contribution of NTFPs to rural livelihoods and their price determination in areas of varying agro-ecological potential of South Africa. The study used data from 1 200 randomly selected households across four agro-ecological zones of South Africa to quantify the contribution of NTFP income to total household income, the proportion of households selling at least a single NTFP and the nature and extent of use of NTFPs as safety nets in areas of varying agro-ecological potential. In addition, 300 sellers of NTFPs in 15 towns across South Africa were interviewed to assess the factors they take into account when setting prices. The findings of this study support the argument that the level of dependence on NFTPs varies with agro-ecological conditions. This was supported by the significant difference between the NTFP incomes of the following pairs of agro-ecological classes: very low and low, medium and high. About 6.4 % households reported selling one or more NTFPs for various reasons, with many (39 %) citing the need to earn cash income and limited employment opportunities (16.9 %). Income from trading NTFPs is undoubtedly an important source of cash income for many rural households. Thus, 300 sellers, selling either at home or in town, were interviewed and the majority (79.3 %) of the sellers reported that selling NTFPs was their main source of cash household income, with only 8 % and 5.7 % receiving their main cash household income from state child grants and state pension grants, respectively. The pricing factors considered by sellers when setting the prices of NTFPs tended to vary with the type of NTFP being sold, type of market (home markets or urban markets) and the method used by the seller to procure the stock. However, overall, transport costs (29 %), stock price (18.4 %), profit margin (12.7 %), time taken to collect or produce the product (7.3 %) and the market price (6.4 %) were the widely used factors to determine prices for NTFPs. The reported various pricing factors showed that there was no formal or certain price mechanism that was used by the sellers of NTFPs to establish the market prices of NTFPs. The study found that about 79 % of the total households interviewed experienced at least one shock of some magnitude in the previous 12 months. The most common shocks were illness (43 %), death (42 %), crop failure (29 %) and hunger (22 %). The households employed various coping strategies (21) in response to different types of shocks, with the three widely used strategies being assistance from friends and relatives (60.1 %), using cash savings (37.9%) and using NTFPs (35.6 %). Shocks, hunger or food shortage and crop failure were significantly and positively related to the usage of NTFPs as safety nets. Therefore, households who experienced hunger or food shortage and crop failure were likely to use NTFPs to cope with these shocks. The study concluded that NTFPs are an integral part of the rural livelihoods, especially for the households living close to the survival line.
- Full Text:
- Date Issued: 2017
- Authors: Mugido, Worship
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5176 , vital:20783
- Description: A large number of studies have been conducted on the contribution of different types of non-timber forest products (NTFPs) to rural livelihoods. However, not many of these have considered the context in which these contributions are made, especially agro-ecological potential. Similarly, there are few studies that focus on the price setting of NTFPs in different settings as most are based on a single or relatively few sites. Thus, there is no indication of the prevalence of the different factors within a uniform macro context, nor how they might vary between different types of NTFPs. Therefore, the aim of this thesis was to establish the contribution of NTFPs to rural livelihoods and their price determination in areas of varying agro-ecological potential of South Africa. The study used data from 1 200 randomly selected households across four agro-ecological zones of South Africa to quantify the contribution of NTFP income to total household income, the proportion of households selling at least a single NTFP and the nature and extent of use of NTFPs as safety nets in areas of varying agro-ecological potential. In addition, 300 sellers of NTFPs in 15 towns across South Africa were interviewed to assess the factors they take into account when setting prices. The findings of this study support the argument that the level of dependence on NFTPs varies with agro-ecological conditions. This was supported by the significant difference between the NTFP incomes of the following pairs of agro-ecological classes: very low and low, medium and high. About 6.4 % households reported selling one or more NTFPs for various reasons, with many (39 %) citing the need to earn cash income and limited employment opportunities (16.9 %). Income from trading NTFPs is undoubtedly an important source of cash income for many rural households. Thus, 300 sellers, selling either at home or in town, were interviewed and the majority (79.3 %) of the sellers reported that selling NTFPs was their main source of cash household income, with only 8 % and 5.7 % receiving their main cash household income from state child grants and state pension grants, respectively. The pricing factors considered by sellers when setting the prices of NTFPs tended to vary with the type of NTFP being sold, type of market (home markets or urban markets) and the method used by the seller to procure the stock. However, overall, transport costs (29 %), stock price (18.4 %), profit margin (12.7 %), time taken to collect or produce the product (7.3 %) and the market price (6.4 %) were the widely used factors to determine prices for NTFPs. The reported various pricing factors showed that there was no formal or certain price mechanism that was used by the sellers of NTFPs to establish the market prices of NTFPs. The study found that about 79 % of the total households interviewed experienced at least one shock of some magnitude in the previous 12 months. The most common shocks were illness (43 %), death (42 %), crop failure (29 %) and hunger (22 %). The households employed various coping strategies (21) in response to different types of shocks, with the three widely used strategies being assistance from friends and relatives (60.1 %), using cash savings (37.9%) and using NTFPs (35.6 %). Shocks, hunger or food shortage and crop failure were significantly and positively related to the usage of NTFPs as safety nets. Therefore, households who experienced hunger or food shortage and crop failure were likely to use NTFPs to cope with these shocks. The study concluded that NTFPs are an integral part of the rural livelihoods, especially for the households living close to the survival line.
- Full Text:
- Date Issued: 2017
Enhancing the critical reading skills of student teachers in Namibia : An action research project
- Authors: Dikuwa, Alexander
- Date: 2012
- Subjects: Reading (Higher education) Critical thinking , Teachers -- Training of -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1912 , http://hdl.handle.net/10962/d1007162
- Description: This thesis reports on a responsive action research case study undertaken to teach student teachers to read critically. I undertook this research to gain a basic knowledge about critical reading as well as to form a knowledge base that would enable me to teach it effectively. First, I gave students a diagnostic assessment activity, analyzed the result and established the students’ ability to read a text critically. After I had established the students’ strengths, weaknesses, and the requirements to move students from their existing critical reading competency to an improved one, I reviewed the literature to provide me with a theory of teaching critical reading. The lessons were then planned and taught. The lessons; focus group interviews; researcher’s diary; students’ reflections and non-participant observer comments formed the data of the study. The data were analyzed using the framework of “what went well”, “what did not go well” and “what needs to be improved if the lessons were to be repeated”. The main purpose was to address the goals of the research, which were to find effective ways of teaching critical reading, appropriate critical reading materials, and to identify any pedagogic shortcomings. The 30 students who took part in this research were third-year students studying English Second language and Mother tongue pedagogies to become specialists in the teaching of both at Junior Secondary level (grades 8 – 10). The study was guided by constructivist theory, which underpins learner-centred education, which continues to inform and shape the development of curricula in Namibia.
- Full Text:
- Date Issued: 2012
- Authors: Dikuwa, Alexander
- Date: 2012
- Subjects: Reading (Higher education) Critical thinking , Teachers -- Training of -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1912 , http://hdl.handle.net/10962/d1007162
- Description: This thesis reports on a responsive action research case study undertaken to teach student teachers to read critically. I undertook this research to gain a basic knowledge about critical reading as well as to form a knowledge base that would enable me to teach it effectively. First, I gave students a diagnostic assessment activity, analyzed the result and established the students’ ability to read a text critically. After I had established the students’ strengths, weaknesses, and the requirements to move students from their existing critical reading competency to an improved one, I reviewed the literature to provide me with a theory of teaching critical reading. The lessons were then planned and taught. The lessons; focus group interviews; researcher’s diary; students’ reflections and non-participant observer comments formed the data of the study. The data were analyzed using the framework of “what went well”, “what did not go well” and “what needs to be improved if the lessons were to be repeated”. The main purpose was to address the goals of the research, which were to find effective ways of teaching critical reading, appropriate critical reading materials, and to identify any pedagogic shortcomings. The 30 students who took part in this research were third-year students studying English Second language and Mother tongue pedagogies to become specialists in the teaching of both at Junior Secondary level (grades 8 – 10). The study was guided by constructivist theory, which underpins learner-centred education, which continues to inform and shape the development of curricula in Namibia.
- Full Text:
- Date Issued: 2012
Corporate taxes and the taxation of dividends
- Authors: Williams, John Mark
- Date: 1997
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:890 , http://hdl.handle.net/10962/d1001644
- Description: The classical system of taxation, whereby companies are taxed without a deduction for dividends paid and shareholders are taxed on their dividend receipts, results in double taxation of dividends. Split rate and imputation systems have been developed in an attempt to mitigate the effects of double taxation of dividends. Double taxation of dividends and differences between corporate and maximum individual marginal tax rates result in corporate tax systems lacking neutrality. Distortions arise between organisational forms, between debt and equity financing and between the retention and distribution of profits. Various methods of integrating corporate and individual taxes have been advocated to overcome the lack of neutrality caused by corporate taxes. Following the introduction of the South African Income Tax Act in 1914, a number of taxes relating to dividends have existed. These have included a Dividend Tax, Non-resident Shareholder's Tax, Undistributed Profits Tax and Secondary Tax on Companies, hereafter referred to as STC. STC is a tax on net dividends declared and results in distributed income being taxed at higher rates than retained income. Despite the implementation of group relief provisions, STC results in an inhibition on the reinvestment of profits within the context of a group of companies. It is also a major cause of the lack of neutrality of the South African corporate tax system. As a result of the lack of neutrality and inhibition of group reinvestment caused by STC, a full imputation system is suggested as an alternative to replace STC.
- Full Text:
- Date Issued: 1997
- Authors: Williams, John Mark
- Date: 1997
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:890 , http://hdl.handle.net/10962/d1001644
- Description: The classical system of taxation, whereby companies are taxed without a deduction for dividends paid and shareholders are taxed on their dividend receipts, results in double taxation of dividends. Split rate and imputation systems have been developed in an attempt to mitigate the effects of double taxation of dividends. Double taxation of dividends and differences between corporate and maximum individual marginal tax rates result in corporate tax systems lacking neutrality. Distortions arise between organisational forms, between debt and equity financing and between the retention and distribution of profits. Various methods of integrating corporate and individual taxes have been advocated to overcome the lack of neutrality caused by corporate taxes. Following the introduction of the South African Income Tax Act in 1914, a number of taxes relating to dividends have existed. These have included a Dividend Tax, Non-resident Shareholder's Tax, Undistributed Profits Tax and Secondary Tax on Companies, hereafter referred to as STC. STC is a tax on net dividends declared and results in distributed income being taxed at higher rates than retained income. Despite the implementation of group relief provisions, STC results in an inhibition on the reinvestment of profits within the context of a group of companies. It is also a major cause of the lack of neutrality of the South African corporate tax system. As a result of the lack of neutrality and inhibition of group reinvestment caused by STC, a full imputation system is suggested as an alternative to replace STC.
- Full Text:
- Date Issued: 1997
Understanding change and implications of divisional management model (DMM ) in a merged multi- campus University in South Africa
- Authors: Mantashe, Lunga Xolisa
- Date: 2014
- Subjects: Organizational change
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/6103 , vital:29491
- Description: The study sought to understand change and transition in a multi-merged campus university in South Africa. Specifically the objectives were to understand the Human Resource (HR) plan, how it is being rolled out, the reactions of workers to it, the effects of the plan on workers and the processes put in place to mitigate, rather than aggravate, the current and foreseeable consequences of the Human Resource plan. A qualitative case study was used and focus groups and semi-structured interviews (triangulated with observation and document analysis) were used on a purposive sample of unions and the university HR official in one campus. The researcher found that there is no organogram which acts as a framework wherein all workers in respective campuses shall fit in. additionally, there is no staff transition plan and harmonisation of conditions of service policy that is agreed upon. Though it seemed there were some mechanisms to attenuate the effects of the HR plan (possible retrenchments, loss of morale, uncertainty, stress, doubt and the like) such as voluntary service package, there were areas of concern about the lack of a properly and widely circulated plan, and the absence of plans to transition staff throughout the process of change. Consequently, the researcher recommended at the end of the study that there must be a change management leadership in each campus to drive transition, a creation of proper communication networks, institution of campus indabas, a design of a transition plan, harmonisation approaches, migration of institutional items to an institutional site and the facilitation of recognition agreements for those unions which are still recognise in the premerger manner.
- Full Text:
- Date Issued: 2014
- Authors: Mantashe, Lunga Xolisa
- Date: 2014
- Subjects: Organizational change
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10353/6103 , vital:29491
- Description: The study sought to understand change and transition in a multi-merged campus university in South Africa. Specifically the objectives were to understand the Human Resource (HR) plan, how it is being rolled out, the reactions of workers to it, the effects of the plan on workers and the processes put in place to mitigate, rather than aggravate, the current and foreseeable consequences of the Human Resource plan. A qualitative case study was used and focus groups and semi-structured interviews (triangulated with observation and document analysis) were used on a purposive sample of unions and the university HR official in one campus. The researcher found that there is no organogram which acts as a framework wherein all workers in respective campuses shall fit in. additionally, there is no staff transition plan and harmonisation of conditions of service policy that is agreed upon. Though it seemed there were some mechanisms to attenuate the effects of the HR plan (possible retrenchments, loss of morale, uncertainty, stress, doubt and the like) such as voluntary service package, there were areas of concern about the lack of a properly and widely circulated plan, and the absence of plans to transition staff throughout the process of change. Consequently, the researcher recommended at the end of the study that there must be a change management leadership in each campus to drive transition, a creation of proper communication networks, institution of campus indabas, a design of a transition plan, harmonisation approaches, migration of institutional items to an institutional site and the facilitation of recognition agreements for those unions which are still recognise in the premerger manner.
- Full Text:
- Date Issued: 2014
Studies on the completely mixed activated sludge treatment of fellmongery and tannery lime-sulphide effluents
- Authors: Rawlings, Douglas Eric
- Date: 1977
- Subjects: Tanneries -- Waste disposal , Sewage sludge -- South Africa -- Management , Sewage -- Purificiation -- Biological treatment , Water quality management -- South Africa , Water -- Purification -- Biological treatment -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4112 , http://hdl.handle.net/10962/d1013052
- Description: Industries producing highly polluted waste waters are having to purify their effluents to meet with ever increasing requirements laid down by water authorities. The South African Water Act of 1956 has prescribed a very high standard to which waste waters must conform before discharge into a South African water course. Enforcement of these standards falls under the jurisdiction of government authorities such as the Department of Water Affairs. Similarly, municipalities and other local authorities set standards with which trade effluents must comply before discharge into public sewers for treatment in a municipal sewage works. These local authorities are empowered to recover from the trader the additional costs incurred in treating trade effluents. Costs are usually levied in respect of volume, oxygen demand, settleable solids and the production of secondary sludge. In recent years, these standards have been enforced to an extent where the survival of several industries has become dependant on whether these industries are able to purify or dispose of their effluents in a manner acceptable to the water authorities. Chap. 1, p. 1.
- Full Text:
- Date Issued: 1977
- Authors: Rawlings, Douglas Eric
- Date: 1977
- Subjects: Tanneries -- Waste disposal , Sewage sludge -- South Africa -- Management , Sewage -- Purificiation -- Biological treatment , Water quality management -- South Africa , Water -- Purification -- Biological treatment -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4112 , http://hdl.handle.net/10962/d1013052
- Description: Industries producing highly polluted waste waters are having to purify their effluents to meet with ever increasing requirements laid down by water authorities. The South African Water Act of 1956 has prescribed a very high standard to which waste waters must conform before discharge into a South African water course. Enforcement of these standards falls under the jurisdiction of government authorities such as the Department of Water Affairs. Similarly, municipalities and other local authorities set standards with which trade effluents must comply before discharge into public sewers for treatment in a municipal sewage works. These local authorities are empowered to recover from the trader the additional costs incurred in treating trade effluents. Costs are usually levied in respect of volume, oxygen demand, settleable solids and the production of secondary sludge. In recent years, these standards have been enforced to an extent where the survival of several industries has become dependant on whether these industries are able to purify or dispose of their effluents in a manner acceptable to the water authorities. Chap. 1, p. 1.
- Full Text:
- Date Issued: 1977
The life and work of Benjamin Tyamzashe: a contemporary Xhosa composer
- Authors: Hansen, Deirdre Doris
- Date: 1968
- Subjects: Tyamzashe, Benjamin, 1890 -- Criticism and interpretation Xhosa (African people) -- Music Hymns, Xhosa Composers, Black -- South Africa
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2639 , http://hdl.handle.net/10962/d1002304
- Description: In this study I have tried to show what Tyamzashe has achieved without the solid musical training any composer worthy of the name should undergo. I have also tried to show the forming of his own musical style under the impact of outside influences. This study is therefore not to teach one anything new, but simply to communicate the results of three years research. In it I have attempted to set the scene in which Tyamzashe's life unfolded itself under the influences of people and circumstances. In doing so I have tried to bear in mind the main theme - Tyamzashe himself. My problem was not so much what to include but what to leave out; thus I have not provided the scene with a detailed background. The section on missionary contact is necessary for an understanding of the great changes brought about by culture contact, as well as for putting Tyamzashe into his historical background. I have also stressed Lovedale because musical change as exemplified in the music of early Bantu converts was centralized there. Finally, the thesis of this study is: despite the changes introduced into Bantu music by culture contact, one perceives, in the works of Tyamzashe, the beginnings of a new pattern of integration. p. 2-3.
- Full Text:
- Date Issued: 1968
- Authors: Hansen, Deirdre Doris
- Date: 1968
- Subjects: Tyamzashe, Benjamin, 1890 -- Criticism and interpretation Xhosa (African people) -- Music Hymns, Xhosa Composers, Black -- South Africa
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2639 , http://hdl.handle.net/10962/d1002304
- Description: In this study I have tried to show what Tyamzashe has achieved without the solid musical training any composer worthy of the name should undergo. I have also tried to show the forming of his own musical style under the impact of outside influences. This study is therefore not to teach one anything new, but simply to communicate the results of three years research. In it I have attempted to set the scene in which Tyamzashe's life unfolded itself under the influences of people and circumstances. In doing so I have tried to bear in mind the main theme - Tyamzashe himself. My problem was not so much what to include but what to leave out; thus I have not provided the scene with a detailed background. The section on missionary contact is necessary for an understanding of the great changes brought about by culture contact, as well as for putting Tyamzashe into his historical background. I have also stressed Lovedale because musical change as exemplified in the music of early Bantu converts was centralized there. Finally, the thesis of this study is: despite the changes introduced into Bantu music by culture contact, one perceives, in the works of Tyamzashe, the beginnings of a new pattern of integration. p. 2-3.
- Full Text:
- Date Issued: 1968