The effect of nutrient levels and ratios on the growth of Microcystis aeruginosa and microcystin production
- Authors: Sember, Craig Stewart
- Date: 2002
- Subjects: Microcystis aeruginosa -- Toxicology , Nitrates , Microcystins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11076 , http://hdl.handle.net/10948/287 , Microcystis aeruginosa -- Toxicology , Nitrates , Microcystins
- Description: This study reports the findings on the effect of nitrates and phosphates on the biomass and toxin production of various strains of the unicellular non-nitrogen fixing cyanobacterium, Microcystis aeruginosa. The occurrence of blooms of Microcystis aeruginosa and microcystin in freshwater impoundments across the globe has been on the increase lately due to increased levels of eutrophication, resulting in human and animal deaths and illness, as well as drinking and recreational water foulment. A range of environmental factors have been shown to effect growth and microcystin production. Existing literature however is somewhat contradictory as to the effects of these physical and chemical factors on toxin production. Therefore Microcystis aeruginosa strains were cultured under batch and continuous conditions to determine the effect of nitrate and phosphate concentrations and ratios on biomass and toxin production. Cultures were analysed with regards to internal nutrient stores, biomass production, nutrient depletion, photosynthetic efficiency and microcystin production. Results showed that microcystin production correlated to growth rate, photosynthetic efficiency and internal nitrogen stores and that an optimal N:P ratio was associated with microcystin levels, growth rate and photosynthetic efficiency. Results therefore led to the conclusion that the nitrogen, carbon, and phosphate balance within the cell is closely associated with microcystin production. Whether or not microcystin is produced to maintain this balance or produced as a function of this balance remains to be determined.
- Full Text:
- Date Issued: 2002
- Authors: Sember, Craig Stewart
- Date: 2002
- Subjects: Microcystis aeruginosa -- Toxicology , Nitrates , Microcystins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11076 , http://hdl.handle.net/10948/287 , Microcystis aeruginosa -- Toxicology , Nitrates , Microcystins
- Description: This study reports the findings on the effect of nitrates and phosphates on the biomass and toxin production of various strains of the unicellular non-nitrogen fixing cyanobacterium, Microcystis aeruginosa. The occurrence of blooms of Microcystis aeruginosa and microcystin in freshwater impoundments across the globe has been on the increase lately due to increased levels of eutrophication, resulting in human and animal deaths and illness, as well as drinking and recreational water foulment. A range of environmental factors have been shown to effect growth and microcystin production. Existing literature however is somewhat contradictory as to the effects of these physical and chemical factors on toxin production. Therefore Microcystis aeruginosa strains were cultured under batch and continuous conditions to determine the effect of nitrate and phosphate concentrations and ratios on biomass and toxin production. Cultures were analysed with regards to internal nutrient stores, biomass production, nutrient depletion, photosynthetic efficiency and microcystin production. Results showed that microcystin production correlated to growth rate, photosynthetic efficiency and internal nitrogen stores and that an optimal N:P ratio was associated with microcystin levels, growth rate and photosynthetic efficiency. Results therefore led to the conclusion that the nitrogen, carbon, and phosphate balance within the cell is closely associated with microcystin production. Whether or not microcystin is produced to maintain this balance or produced as a function of this balance remains to be determined.
- Full Text:
- Date Issued: 2002
The effect of selenium in the detoxification of the microcystin hepatotoxins
- Authors: Downs, Kerry
- Date: 2002
- Subjects: Cynaobacterial toxins , Microcystins , Selenium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11070 , http://hdl.handle.net/10948/284 , Cynaobacterial toxins , Microcystins , Selenium
- Description: Blooms of cyanobacteria have been known to cause illness in humans and death in wild and domestic animals. One of the toxins produced by cyanobacteria is microcystin, which is a potent hepatotoxin. Microcystin is taken up by bile acid transporters in the intestine and transported into the liver. After exposure to acute doses of microcystin, severe haemorrhage has been observed along with apoptotic and necrotic hepatocytes. The cytoskeletal structure of the hepatocytes is disrupted and oxidative stress is induced. Selenium, a known anti-oxidant, has been shown to induce increased activity of glutathione peroxidase. Glutathione peroxidase removes peroxides from cells protecting them from oxidative stress. This study set out to determine if selenium could play a role in preventing the damage to mice livers due to microcystin toxin. The protective role of selenium was explored in three main studies: in the first study, the ability of selenium to increase the survival time of mice exposed to a lethal dose of toxin was determined. In the second study the mice were exposed to sublethal chronic doses of toxin over 30 days. The ability of selenium to minimise liver damage under these conditions was determined. The final study investigated the mechanism of the protective effect of selenium. The results of the first study suggested that selenium could extend survival time. In the second study the selenium supplemented mice showed a reduction in the extent of the increase in liver weight and a decrease in the amount of lipid peroxidation induced compared to the mice that received only toxin. The histology of the selenium supplemented mice also showed a decrease in the severity and amount of morphological changes in the liver. The third study indicated that the protection shown by selenium might be mediated by an increase in the glutathione peroxidase (GPX) activity in selenium supplemented mice. This increase in GPX activity would increase the removal of the lipid hydroperoxides and prevent the damage they would cause in the cell. A further result indicated an increase in glutathione S-transferase in only the toxin control mice when compared to the selenium supplemented and control mice. ii In conclusion selenium offers protection against microcystin but further studies need to be done to provide statistically valid results to clarify the level of protection.
- Full Text:
- Date Issued: 2002
- Authors: Downs, Kerry
- Date: 2002
- Subjects: Cynaobacterial toxins , Microcystins , Selenium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11070 , http://hdl.handle.net/10948/284 , Cynaobacterial toxins , Microcystins , Selenium
- Description: Blooms of cyanobacteria have been known to cause illness in humans and death in wild and domestic animals. One of the toxins produced by cyanobacteria is microcystin, which is a potent hepatotoxin. Microcystin is taken up by bile acid transporters in the intestine and transported into the liver. After exposure to acute doses of microcystin, severe haemorrhage has been observed along with apoptotic and necrotic hepatocytes. The cytoskeletal structure of the hepatocytes is disrupted and oxidative stress is induced. Selenium, a known anti-oxidant, has been shown to induce increased activity of glutathione peroxidase. Glutathione peroxidase removes peroxides from cells protecting them from oxidative stress. This study set out to determine if selenium could play a role in preventing the damage to mice livers due to microcystin toxin. The protective role of selenium was explored in three main studies: in the first study, the ability of selenium to increase the survival time of mice exposed to a lethal dose of toxin was determined. In the second study the mice were exposed to sublethal chronic doses of toxin over 30 days. The ability of selenium to minimise liver damage under these conditions was determined. The final study investigated the mechanism of the protective effect of selenium. The results of the first study suggested that selenium could extend survival time. In the second study the selenium supplemented mice showed a reduction in the extent of the increase in liver weight and a decrease in the amount of lipid peroxidation induced compared to the mice that received only toxin. The histology of the selenium supplemented mice also showed a decrease in the severity and amount of morphological changes in the liver. The third study indicated that the protection shown by selenium might be mediated by an increase in the glutathione peroxidase (GPX) activity in selenium supplemented mice. This increase in GPX activity would increase the removal of the lipid hydroperoxides and prevent the damage they would cause in the cell. A further result indicated an increase in glutathione S-transferase in only the toxin control mice when compared to the selenium supplemented and control mice. ii In conclusion selenium offers protection against microcystin but further studies need to be done to provide statistically valid results to clarify the level of protection.
- Full Text:
- Date Issued: 2002
The effects of goat browsing on ecosystem patterns and processes in succulent thicket, South Africa
- Lechmere-Oertel, Richard Geoffrey
- Authors: Lechmere-Oertel, Richard Geoffrey
- Date: 2003
- Subjects: Succulent plants -- South Africa -- Eastern Cape , Landscape ecology -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11074 , http://hdl.handle.net/10948/309 , Succulent plants -- South Africa -- Eastern Cape , Landscape ecology -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Description: Transformation in the arid succulent thicket of the Eastern Cape of South Africa in response to unsustainable livestock production has been widespread, with less than 10 percent remaining intact. Transformation in succulent thicket has resulted in large areas of dense thicket (comprising a two-phase mosaic of perennial-vegetated patches separated by animal paths and bare patches) being replaced with a ‘pseudo-savanna’ of remnant canopy trees with a structurally simple field layer of ephemeral and short- lived perennial grasses and forbs. There is an extensive literature describing the transformation of succulent thicket, with many speculative statements about the underlying mechanisms of transformation. The central focus of this study was to improve our mechanistic understanding of transformation in succulent thicket using field experiments. Hopefully these results will set another foundation upon which future management of succulent thicket can be improved and large-scale restoration initiated. This study comprises four themes that are linked to the concept of landscape function. The central premise of landscape function is that functional landscapes have mechanisms that capture and retain scarce resources. Conversely, as landscapes become increasingly dysfunctional, so these mechanisms become disrupted. In succulent thicket, dysfunctio n appears to be linked to the reduced ability to harvest water, cycle carbon and a loss of organic carbon. In this thesis I examined some of the key processes that influence water and organic carbon fluxes: perennial vegetation cover, soil fertility, litter fall and decomposition, and runoff and soil erosion. The experimental design that was used for all this work was a factorial ANOVA based on replicated fenceline contrasts that reflect differences in long-term management history. The main objectives of this thesis were to: quantify the patterns of transformation in an arid form of succulent thicket, including changes in the biomass, cover and structure of the dominant vegetation guilds; test the stability of the transformed succulent thicket ecosystem to show whether it is a new stable state or an intermediate stage in a trajectory towards a highly desertified state where only the ephemeral grasses and forbs persist; describe and compare soil fertility across transformation contrasts, concentrating on changes in the spatial patterns of soil resources and the ability of the soil to harvest precipitation; to compare litter fall and decomposition of leaf material from the dominant plants in intact and transformed succulent thicket; to quantify and compare run-off and erosion from run-off plots in intact and transformed succulent thicket. Transformation and stability I quantified the changes in plant diversity, physiognomy and biomass that occur across transformation contrasts. Thicket transformation results in a significant loss of plant diversity and functional types. There is also a significant reduction in the biomass (c. 80 t.ha-1) and structural complexity of the vegetation, both vertically and horizontally. These results were interpreted in terms of their implications for ecosystem functioning and stability. To test the stability of the transformed succulent thicket I used aerial photographs and ground-truthing to track the survivorship of canopy trees over 60 years in pseudo-savanna landscapes. I also measured seedling establishment in different habitats. I show that the pseudo-savanna is not a stable state owing to ongoing adult mortality and no recruitment of canopy trees. Soil fertility and water status I hypothesised that the above-ground changes in ve getation would be accompanied by similar trends in the pattern and levels of soil nutrient resources and the ability of the landscape to harvest precipitation. I compared soil fertility (organic carbon, available nitrogen and phosphorus), texture, matric potential, and surface micro-topography in the two main micro- habitats on either side of the replicated fenceline contrasts. The results show that intact spekboom thicket has a distinct spatial pattern of soil fertility where nutrients and organic carbon are concentrated under the patches of perennial shrubs, compared to under canopy trees and open spaces. Transformation results in a significant homogenisation out of this pattern and an overall reduction in the fertility of the landscape. The proportion of the landscape surface that would promote infiltration of water decreases from 60 – 0.6 percent. Soil moisture retention (matric potential) also decreases with transformation. I interpreted these patterns in terms of the ability of the landscape to harvest and release water after rainfall events. Litter fall and decomposition Surface litter and soil organic matter are critical components to wooded ecosystems; contributing to several ecosystem functions. The rates of litter fall and decomposition are ratelimiting steps in nutrient cycling and incorporation of organic matter into the soil. The ecological mechanisms behind the collapse of succulent thicket in the face of domestic herbivory are not fully understood, but are believed to include the breakdown of several ecosystem processes, including litter fall and decomposition. I quantified the changes in litter fall and litter decomposition of four of the dominant perennial woody plants (Euclea undulata, Pappea capensis, Portulacaria afra and Rhus longispina) across the replicated fenceline. Litter fall was measured over 14 months using mesh traps. Decomposition was measured over 15 months using a combination of litterbags and unprotected leaf packs. I also quantified soil microclimate during the experimental period; hypothesising that transformation would lead to soil conditions less amenable for biotic activity. Litter fall in succulent thicket was very high for a semi-arid system, comparing more to temperate forests. The leaf-succulent P. afra contributed the largest single component of the total litter production at a landscape scale. The effect of transformation on litter fall was species specific. Deep-rooted or drought-adapted species showed no change in litter yield with transformation; shallow-rooted species showed a significant decrease. There were few significant differences in decomposition rates across the transformation gradient and between litter types. Portulacaria afra litter had the steepest rate of mass loss, and was most affected by transformation. The more recalcitrant (high C:N ratio) leaves of P. capensis remained largely unaffected by transformation. These results indicate the critical role of the perennial vegetation in incorporating organic carbon into the soil. Transformation of succulent thicket leads to a disruption of the flow of carbon into the soil, reinforcing the cycle of transformation through reduced fertility. Rehabilitation of this ecosystem will require the active establishment of species, such as P. afra, that will restart the flow of carbon into the soil. Run-off & Erosion The landscape function model predicts that functional semi-arid shrublands efficiently conserve limiting resources such as water and water-bourn sediments (soil and organic matter). As these rangelands become transformed through unsustainable livestock production, so their ability to conserve resources decreases. The primary determinant of landscape function and conservation of resources appears to be the proportional cover of perennial vegetation. I hypothesised that the switch from a two-phase mosaic dominated by perennial succulent and woody shrubs to a single phase system dominated by an ephemeral field layer would be accompanied by disruption of the mechanisms that conserve resources. Specifically, I tested the hypothesis that transformation of succulent thicket increases runoff volume, sediment concentration of runoff, soil erosion and loss of organic matter at a patch scale (c. 100 m2). Runoff and water-borne sediment were measured from runoff plots established across replicated fenceline contrasts. Data were collected from eight extreme weather events over two years. There were no significant differences between runoff and erosion across the transformation contrast, as each extreme weather event was unique in terms of its runoff response. The transformed runoff plots alone also gave inconsistent results, largely due to differences in the cover of ephemeral forbs and weakly perennial grasses. Runoff and erosion were not predictable from the data across the transformation gradient due to complex interactions between the nature of the above-ground vegetation, soil micro-topography and land use history. The results highlighted the need for longer-term catchment experiments to generate a predictive understanding of the effect of transformation on runoff and erosion in succulent thicket.
- Full Text:
- Date Issued: 2003
- Authors: Lechmere-Oertel, Richard Geoffrey
- Date: 2003
- Subjects: Succulent plants -- South Africa -- Eastern Cape , Landscape ecology -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11074 , http://hdl.handle.net/10948/309 , Succulent plants -- South Africa -- Eastern Cape , Landscape ecology -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Description: Transformation in the arid succulent thicket of the Eastern Cape of South Africa in response to unsustainable livestock production has been widespread, with less than 10 percent remaining intact. Transformation in succulent thicket has resulted in large areas of dense thicket (comprising a two-phase mosaic of perennial-vegetated patches separated by animal paths and bare patches) being replaced with a ‘pseudo-savanna’ of remnant canopy trees with a structurally simple field layer of ephemeral and short- lived perennial grasses and forbs. There is an extensive literature describing the transformation of succulent thicket, with many speculative statements about the underlying mechanisms of transformation. The central focus of this study was to improve our mechanistic understanding of transformation in succulent thicket using field experiments. Hopefully these results will set another foundation upon which future management of succulent thicket can be improved and large-scale restoration initiated. This study comprises four themes that are linked to the concept of landscape function. The central premise of landscape function is that functional landscapes have mechanisms that capture and retain scarce resources. Conversely, as landscapes become increasingly dysfunctional, so these mechanisms become disrupted. In succulent thicket, dysfunctio n appears to be linked to the reduced ability to harvest water, cycle carbon and a loss of organic carbon. In this thesis I examined some of the key processes that influence water and organic carbon fluxes: perennial vegetation cover, soil fertility, litter fall and decomposition, and runoff and soil erosion. The experimental design that was used for all this work was a factorial ANOVA based on replicated fenceline contrasts that reflect differences in long-term management history. The main objectives of this thesis were to: quantify the patterns of transformation in an arid form of succulent thicket, including changes in the biomass, cover and structure of the dominant vegetation guilds; test the stability of the transformed succulent thicket ecosystem to show whether it is a new stable state or an intermediate stage in a trajectory towards a highly desertified state where only the ephemeral grasses and forbs persist; describe and compare soil fertility across transformation contrasts, concentrating on changes in the spatial patterns of soil resources and the ability of the soil to harvest precipitation; to compare litter fall and decomposition of leaf material from the dominant plants in intact and transformed succulent thicket; to quantify and compare run-off and erosion from run-off plots in intact and transformed succulent thicket. Transformation and stability I quantified the changes in plant diversity, physiognomy and biomass that occur across transformation contrasts. Thicket transformation results in a significant loss of plant diversity and functional types. There is also a significant reduction in the biomass (c. 80 t.ha-1) and structural complexity of the vegetation, both vertically and horizontally. These results were interpreted in terms of their implications for ecosystem functioning and stability. To test the stability of the transformed succulent thicket I used aerial photographs and ground-truthing to track the survivorship of canopy trees over 60 years in pseudo-savanna landscapes. I also measured seedling establishment in different habitats. I show that the pseudo-savanna is not a stable state owing to ongoing adult mortality and no recruitment of canopy trees. Soil fertility and water status I hypothesised that the above-ground changes in ve getation would be accompanied by similar trends in the pattern and levels of soil nutrient resources and the ability of the landscape to harvest precipitation. I compared soil fertility (organic carbon, available nitrogen and phosphorus), texture, matric potential, and surface micro-topography in the two main micro- habitats on either side of the replicated fenceline contrasts. The results show that intact spekboom thicket has a distinct spatial pattern of soil fertility where nutrients and organic carbon are concentrated under the patches of perennial shrubs, compared to under canopy trees and open spaces. Transformation results in a significant homogenisation out of this pattern and an overall reduction in the fertility of the landscape. The proportion of the landscape surface that would promote infiltration of water decreases from 60 – 0.6 percent. Soil moisture retention (matric potential) also decreases with transformation. I interpreted these patterns in terms of the ability of the landscape to harvest and release water after rainfall events. Litter fall and decomposition Surface litter and soil organic matter are critical components to wooded ecosystems; contributing to several ecosystem functions. The rates of litter fall and decomposition are ratelimiting steps in nutrient cycling and incorporation of organic matter into the soil. The ecological mechanisms behind the collapse of succulent thicket in the face of domestic herbivory are not fully understood, but are believed to include the breakdown of several ecosystem processes, including litter fall and decomposition. I quantified the changes in litter fall and litter decomposition of four of the dominant perennial woody plants (Euclea undulata, Pappea capensis, Portulacaria afra and Rhus longispina) across the replicated fenceline. Litter fall was measured over 14 months using mesh traps. Decomposition was measured over 15 months using a combination of litterbags and unprotected leaf packs. I also quantified soil microclimate during the experimental period; hypothesising that transformation would lead to soil conditions less amenable for biotic activity. Litter fall in succulent thicket was very high for a semi-arid system, comparing more to temperate forests. The leaf-succulent P. afra contributed the largest single component of the total litter production at a landscape scale. The effect of transformation on litter fall was species specific. Deep-rooted or drought-adapted species showed no change in litter yield with transformation; shallow-rooted species showed a significant decrease. There were few significant differences in decomposition rates across the transformation gradient and between litter types. Portulacaria afra litter had the steepest rate of mass loss, and was most affected by transformation. The more recalcitrant (high C:N ratio) leaves of P. capensis remained largely unaffected by transformation. These results indicate the critical role of the perennial vegetation in incorporating organic carbon into the soil. Transformation of succulent thicket leads to a disruption of the flow of carbon into the soil, reinforcing the cycle of transformation through reduced fertility. Rehabilitation of this ecosystem will require the active establishment of species, such as P. afra, that will restart the flow of carbon into the soil. Run-off & Erosion The landscape function model predicts that functional semi-arid shrublands efficiently conserve limiting resources such as water and water-bourn sediments (soil and organic matter). As these rangelands become transformed through unsustainable livestock production, so their ability to conserve resources decreases. The primary determinant of landscape function and conservation of resources appears to be the proportional cover of perennial vegetation. I hypothesised that the switch from a two-phase mosaic dominated by perennial succulent and woody shrubs to a single phase system dominated by an ephemeral field layer would be accompanied by disruption of the mechanisms that conserve resources. Specifically, I tested the hypothesis that transformation of succulent thicket increases runoff volume, sediment concentration of runoff, soil erosion and loss of organic matter at a patch scale (c. 100 m2). Runoff and water-borne sediment were measured from runoff plots established across replicated fenceline contrasts. Data were collected from eight extreme weather events over two years. There were no significant differences between runoff and erosion across the transformation contrast, as each extreme weather event was unique in terms of its runoff response. The transformed runoff plots alone also gave inconsistent results, largely due to differences in the cover of ephemeral forbs and weakly perennial grasses. Runoff and erosion were not predictable from the data across the transformation gradient due to complex interactions between the nature of the above-ground vegetation, soil micro-topography and land use history. The results highlighted the need for longer-term catchment experiments to generate a predictive understanding of the effect of transformation on runoff and erosion in succulent thicket.
- Full Text:
- Date Issued: 2003
The effects of selected proline-based cyclic dipeptides on growth and induction of apoptosis in cancer cells
- Authors: Brauns, Seth Clint Aron
- Date: 2004
- Subjects: Cyclic peptides , Antineoplastic agents -- Testing , Apoptosis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11088 , http://hdl.handle.net/10948/396 , Cyclic peptides , Antineoplastic agents -- Testing , Apoptosis
- Description: An increasing number of cyclic dipeptides (CDPs) have been shown to exhibit important biological activity including antifungal, antibacterial, anticonvulsant and immunomodulatory activity. Furthermore, some CDP derivatives have been shown to exhibit antitumour activity in vitro and in vivo. Several proline-based CDPs that exhibit biological activity have been detected in various processed foods and beverages. In the present study, the potential of seven proline-based CDPs to inhibit cancer cell growth was investigated in HT-29 (colon), HeLa (cervical), MCF-7 (breast) and WHCO3 (oesophageal) cancer cell lines. The CDPs used in this study were cyclo(Phe-Pro), cyclo(Tyr-Pro), cyclo(Gly-Pro), cyclo(Pro- Pro), cyclo(His-Pro), cyclo(Leu-Pro) and cyclo(Thr-Pro). The sulforhodamine B (SRB) cell growth assay was used in an initial screening phase to investigate the effects of the CDPs in HT-29, HeLa and MCF-7 cells. After exposing the cells to 10mM of the respective CDPs for 48 hours, the SRB assay results showed that only cyclo(Phe-Pro) exhibited more than 50% growth inhibition (p<0.01) in the three cell lines. The other CDPs showed comparatively marginal growth-inhibitory effects, except for cyclo(Tyr-Pro), which exhibited a pronounced effect in MCF-7 cells compared to HT-29 and HeLa cells. The MTT assay was used to confirm the SRB assay results for cyclo(Phe-Pro) and cyclo(Tyr-Pro), extending the investigation to the use of the fourth cell line WHCO3 and using a longer exposure time of 72 hours. The MTT assay demonstrated a dosedependent (0.008-10 mM) growth inhibition by cyclo(Phe-Pro) with an IC50 value of 4.04 ± 1.15 mM for HT-29 cells. Cyclo(Phe-Pro) was subsequently used to investigate whether the growth-inhibitory effects of this CDP were related to the induction of apoptosis in HT-29 cells. Hoechst 33342 staining showed that 5mM cyclo(Phe-Pro) induced characteristic chromatin condensation and nuclear fragmentation in 18.3 ± 2.8% (p<0.01) of HT-29 cells after 72 hours. Furthermore, annexin V binding revealed that HT-29 cells treated with 5 mM cyclo(Phe-Pro) displayed phosphatidylserine externalization after 48 hours. In addition, it was shown that 10 mM cyclo(Phe-Pro) induced poly(ADP-ribose)polymerase PARP cleavage, one of the hallmark events of apoptosis. The use of the broad-range caspase inhibitor Z-VAD-FMK, showed that this PARP cleavage was caspase-dependent, which in turn was confirmed by demonstrating an increase in caspase-3 activity (p<0.01) in cyclo(Phe- Pro)-treated HT-29 cells. In conclusion, these findings demonstrate that cyclo(Phe-Pro) inhibited the growth of HT- 29, MCF-7, HeLa and WHCO3 cells, and induced apoptosis in HT-29 colon cancer cells, suggesting the potential antitumour activity of cyclo(Phe-Pro)-related CDPs.
- Full Text:
- Date Issued: 2004
- Authors: Brauns, Seth Clint Aron
- Date: 2004
- Subjects: Cyclic peptides , Antineoplastic agents -- Testing , Apoptosis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11088 , http://hdl.handle.net/10948/396 , Cyclic peptides , Antineoplastic agents -- Testing , Apoptosis
- Description: An increasing number of cyclic dipeptides (CDPs) have been shown to exhibit important biological activity including antifungal, antibacterial, anticonvulsant and immunomodulatory activity. Furthermore, some CDP derivatives have been shown to exhibit antitumour activity in vitro and in vivo. Several proline-based CDPs that exhibit biological activity have been detected in various processed foods and beverages. In the present study, the potential of seven proline-based CDPs to inhibit cancer cell growth was investigated in HT-29 (colon), HeLa (cervical), MCF-7 (breast) and WHCO3 (oesophageal) cancer cell lines. The CDPs used in this study were cyclo(Phe-Pro), cyclo(Tyr-Pro), cyclo(Gly-Pro), cyclo(Pro- Pro), cyclo(His-Pro), cyclo(Leu-Pro) and cyclo(Thr-Pro). The sulforhodamine B (SRB) cell growth assay was used in an initial screening phase to investigate the effects of the CDPs in HT-29, HeLa and MCF-7 cells. After exposing the cells to 10mM of the respective CDPs for 48 hours, the SRB assay results showed that only cyclo(Phe-Pro) exhibited more than 50% growth inhibition (p<0.01) in the three cell lines. The other CDPs showed comparatively marginal growth-inhibitory effects, except for cyclo(Tyr-Pro), which exhibited a pronounced effect in MCF-7 cells compared to HT-29 and HeLa cells. The MTT assay was used to confirm the SRB assay results for cyclo(Phe-Pro) and cyclo(Tyr-Pro), extending the investigation to the use of the fourth cell line WHCO3 and using a longer exposure time of 72 hours. The MTT assay demonstrated a dosedependent (0.008-10 mM) growth inhibition by cyclo(Phe-Pro) with an IC50 value of 4.04 ± 1.15 mM for HT-29 cells. Cyclo(Phe-Pro) was subsequently used to investigate whether the growth-inhibitory effects of this CDP were related to the induction of apoptosis in HT-29 cells. Hoechst 33342 staining showed that 5mM cyclo(Phe-Pro) induced characteristic chromatin condensation and nuclear fragmentation in 18.3 ± 2.8% (p<0.01) of HT-29 cells after 72 hours. Furthermore, annexin V binding revealed that HT-29 cells treated with 5 mM cyclo(Phe-Pro) displayed phosphatidylserine externalization after 48 hours. In addition, it was shown that 10 mM cyclo(Phe-Pro) induced poly(ADP-ribose)polymerase PARP cleavage, one of the hallmark events of apoptosis. The use of the broad-range caspase inhibitor Z-VAD-FMK, showed that this PARP cleavage was caspase-dependent, which in turn was confirmed by demonstrating an increase in caspase-3 activity (p<0.01) in cyclo(Phe- Pro)-treated HT-29 cells. In conclusion, these findings demonstrate that cyclo(Phe-Pro) inhibited the growth of HT- 29, MCF-7, HeLa and WHCO3 cells, and induced apoptosis in HT-29 colon cancer cells, suggesting the potential antitumour activity of cyclo(Phe-Pro)-related CDPs.
- Full Text:
- Date Issued: 2004
The execution of the financial management function in small to medium-sized building contractors as a means of promoting business sustainability
- Authors: Bekker, Jakobus Petrus
- Date: 2004
- Subjects: Contractors' operation -- Finance , Construction industry -- Finance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11004 , http://hdl.handle.net/10948/336 , Contractors' operation -- Finance , Construction industry -- Finance
- Description: The objective of this study was to investigate the extent to which small to medium-sized building contractors beneficially utilise the financial management function in their enterprises to improve and ensure business sustainability. Financial management focuses on the principles of decision-making, which requires action, without perfect knowledge of the outcome. To effectively execute the financial function, using the primary inputs in decision-making, financial management requires the ability to: understand and interpret financial statements and reports; make reasoned and objective decisions in controlling the operations of the enterprise; have a thorough knowledge of the internal functioning of the enterprise; and have a thorough knowledge of current and expected future economic conditions in the external environment. To do this, requires an effectively applied financial management function in the enterprises, which includes the utilisation of the financial management criteria to ensure business sustainability. However, without an appreciation of what financial management is, how important financial management is, and how financial management must be applied in the enterprise, small to medium-sized building contractors will find it difficult to effectively perform the financial management function and its different activities. It was therefore important to determine how well owners and construction managers of the average small to medium-sized building contractor deal with and utilise the financial management function in their enterprises. Consequently, a survey was carried out amongst small to medium-sized building contractors in the Nelson Mandela Metropolitan Municipal (NMMM) area, which revealed information that was used to come to certain conclusions: Firstly, it can be concluded that the financial management function is generally exercised superficially. This is supported by the responses of small to medium-sized building contractors, which implied that more than half the contractors do not fully perform financial management tasks. Secondly, it was concluded that the financial management criteria generally do not play a role in the business sustainability considerations of small to medium-sized building contractors. This is supported by the results, which imply that more than half the contractors do not fully utilise the financial management criteria.
- Full Text:
- Date Issued: 2004
- Authors: Bekker, Jakobus Petrus
- Date: 2004
- Subjects: Contractors' operation -- Finance , Construction industry -- Finance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11004 , http://hdl.handle.net/10948/336 , Contractors' operation -- Finance , Construction industry -- Finance
- Description: The objective of this study was to investigate the extent to which small to medium-sized building contractors beneficially utilise the financial management function in their enterprises to improve and ensure business sustainability. Financial management focuses on the principles of decision-making, which requires action, without perfect knowledge of the outcome. To effectively execute the financial function, using the primary inputs in decision-making, financial management requires the ability to: understand and interpret financial statements and reports; make reasoned and objective decisions in controlling the operations of the enterprise; have a thorough knowledge of the internal functioning of the enterprise; and have a thorough knowledge of current and expected future economic conditions in the external environment. To do this, requires an effectively applied financial management function in the enterprises, which includes the utilisation of the financial management criteria to ensure business sustainability. However, without an appreciation of what financial management is, how important financial management is, and how financial management must be applied in the enterprise, small to medium-sized building contractors will find it difficult to effectively perform the financial management function and its different activities. It was therefore important to determine how well owners and construction managers of the average small to medium-sized building contractor deal with and utilise the financial management function in their enterprises. Consequently, a survey was carried out amongst small to medium-sized building contractors in the Nelson Mandela Metropolitan Municipal (NMMM) area, which revealed information that was used to come to certain conclusions: Firstly, it can be concluded that the financial management function is generally exercised superficially. This is supported by the responses of small to medium-sized building contractors, which implied that more than half the contractors do not fully perform financial management tasks. Secondly, it was concluded that the financial management criteria generally do not play a role in the business sustainability considerations of small to medium-sized building contractors. This is supported by the results, which imply that more than half the contractors do not fully utilise the financial management criteria.
- Full Text:
- Date Issued: 2004
The goddess, the witch and the bitch : three studies in the perception of women
- Authors: Hare, Nicola Tracy
- Date: 2001
- Subjects: Feminism in literature , Women's rights in literature , Feminism and literature , Patriarchy in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10986 , http://hdl.handle.net/10948/278 , Feminism in literature , Women's rights in literature , Feminism and literature , Patriarchy in literature
- Description: In the minds of many people all over the world, women are ‘second class citizens’, standing accused of the downfall of mankind ever since Eve allegedly ate the apple. Even amongst those who do not openly denigrate women, there are many who do so in other, more subtle ways even if they are unaware of it. This study proposes to challenge such a view of women by exposing the ways in which perceptions of women are constructed by society, which frequently wants to maintain the status quo of male dominance. This study employs a feminist approach in examining this gynocentric theme, along with cultural studies which, with its focus on power relations and ways of decentring power structures, is also clearly of use. In addition, this multidisciplinary approach of cultural studies offers the possibility of studying literary texts as well as popular culture. Three specific time periods are examined, with a view to uncovering negative perceptions of women and ways that women can resist such attempts to control them. In chapter one, the focus turns to contemporary perceptions of prehistoric women and the ways that so-called ‘objective’ science has failed to represent women accurately. Similarly, ‘objective’ accounts of Goddess-worship – which frequently fail to examine this phenomenon adequately – are revisited. Alice Walker’s The Temple of My Familiar (1989) is discussed as a text which acts as a site of resistance to societally-informed perceptions. Chapter two continues this investigation by turning to the concept of the witch and its maligned association with women. Woman and witchcraft, having been associated for centuries, are investigated as a pairing which frequently results because iii of attempts to control women by androcentric society. In such situations, the practising of witchcraft can actually become a form of resistance to patriarchy. The pernicious effect of society’s need to purge itself – by witch hunts – of witches is also investigated. The Devil’s Chimney (1997) by Anne Landsman and “The prophetess” (1994) by Njabulo S. Ndebele are discussed as texts which examine fictionalised South African versions of this phenomenon. Sinead O’Connor, the Irish singer, is the ‘bitch’ discussed in chapter three. She is examined as a woman who offers strong and on-going resistance to patriarchal ways of thinking which would ‘box’ women in. This singer refuses to accept societal roles which are offered to women and so offers means of resistance to patriarchy, many of which are discussed in this chapter. This study concludes that it is the responsibility of women to resist patriarchy and to define roles for themselves. The three chapters examine various means of resistance and offer women insight into the forms of opposition they themselves can take.
- Full Text:
- Date Issued: 2001
- Authors: Hare, Nicola Tracy
- Date: 2001
- Subjects: Feminism in literature , Women's rights in literature , Feminism and literature , Patriarchy in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10986 , http://hdl.handle.net/10948/278 , Feminism in literature , Women's rights in literature , Feminism and literature , Patriarchy in literature
- Description: In the minds of many people all over the world, women are ‘second class citizens’, standing accused of the downfall of mankind ever since Eve allegedly ate the apple. Even amongst those who do not openly denigrate women, there are many who do so in other, more subtle ways even if they are unaware of it. This study proposes to challenge such a view of women by exposing the ways in which perceptions of women are constructed by society, which frequently wants to maintain the status quo of male dominance. This study employs a feminist approach in examining this gynocentric theme, along with cultural studies which, with its focus on power relations and ways of decentring power structures, is also clearly of use. In addition, this multidisciplinary approach of cultural studies offers the possibility of studying literary texts as well as popular culture. Three specific time periods are examined, with a view to uncovering negative perceptions of women and ways that women can resist such attempts to control them. In chapter one, the focus turns to contemporary perceptions of prehistoric women and the ways that so-called ‘objective’ science has failed to represent women accurately. Similarly, ‘objective’ accounts of Goddess-worship – which frequently fail to examine this phenomenon adequately – are revisited. Alice Walker’s The Temple of My Familiar (1989) is discussed as a text which acts as a site of resistance to societally-informed perceptions. Chapter two continues this investigation by turning to the concept of the witch and its maligned association with women. Woman and witchcraft, having been associated for centuries, are investigated as a pairing which frequently results because iii of attempts to control women by androcentric society. In such situations, the practising of witchcraft can actually become a form of resistance to patriarchy. The pernicious effect of society’s need to purge itself – by witch hunts – of witches is also investigated. The Devil’s Chimney (1997) by Anne Landsman and “The prophetess” (1994) by Njabulo S. Ndebele are discussed as texts which examine fictionalised South African versions of this phenomenon. Sinead O’Connor, the Irish singer, is the ‘bitch’ discussed in chapter three. She is examined as a woman who offers strong and on-going resistance to patriarchal ways of thinking which would ‘box’ women in. This singer refuses to accept societal roles which are offered to women and so offers means of resistance to patriarchy, many of which are discussed in this chapter. This study concludes that it is the responsibility of women to resist patriarchy and to define roles for themselves. The three chapters examine various means of resistance and offer women insight into the forms of opposition they themselves can take.
- Full Text:
- Date Issued: 2001
The health status of construction workers
- Authors: Deacon, Claire Helen
- Date: 2004
- Subjects: Construction industry -- Employees -- Diseases -- South Africa , Construction workers -- Health and hygiene -- South Africa , Construction workers -- Health risk assessment -- South Africa
- Language: English
- Type: Thesis , Masters , MCur
- Identifier: vital:11025 , http://hdl.handle.net/10948/326 , Construction industry -- Employees -- Diseases -- South Africa , Construction workers -- Health and hygiene -- South Africa , Construction workers -- Health risk assessment -- South Africa
- Description: The construction industry is considered to be an extremely dangerous working environment, and therefore the health status of construction workers needs to be considered prior, during and on leaving the industry. Occupational hazards relative to the construction worker are well researched internationally; however few countries undertake routine medical surveillance to identify the health status of the construction worker relative to these hazards. Employers have a higher duty of care to identify workers who could be a risk at work from non-occupationally related conditions such as hypertension and diabetes mellitus. Work could exacerbate these conditions, leading to absenteeism, poor performance and eventually leaving the industry due to ill health. The dissertation explores, inter alia: the risks to which workers are exposed; the legal aspects; relevant literature regarding medical surveillance, and the use of a medical surveillance instrument used to determine the health status of 142 construction workers who consented to participate in the study. The methodological approach used in this study was a quantitative descriptive design, more specifically, using a randomised cross-sectional survey design. The instrument used to determine health status included a full medical, occupational and social history, as well as a physical examination undertaken by Occupational Health Nursing Practitioners (OHNs). Findings indicate that most construction workers believe they are healthy. However only a small percentage of construction workers did not require referral for further investigation and / or treatment.
- Full Text:
- Authors: Deacon, Claire Helen
- Date: 2004
- Subjects: Construction industry -- Employees -- Diseases -- South Africa , Construction workers -- Health and hygiene -- South Africa , Construction workers -- Health risk assessment -- South Africa
- Language: English
- Type: Thesis , Masters , MCur
- Identifier: vital:11025 , http://hdl.handle.net/10948/326 , Construction industry -- Employees -- Diseases -- South Africa , Construction workers -- Health and hygiene -- South Africa , Construction workers -- Health risk assessment -- South Africa
- Description: The construction industry is considered to be an extremely dangerous working environment, and therefore the health status of construction workers needs to be considered prior, during and on leaving the industry. Occupational hazards relative to the construction worker are well researched internationally; however few countries undertake routine medical surveillance to identify the health status of the construction worker relative to these hazards. Employers have a higher duty of care to identify workers who could be a risk at work from non-occupationally related conditions such as hypertension and diabetes mellitus. Work could exacerbate these conditions, leading to absenteeism, poor performance and eventually leaving the industry due to ill health. The dissertation explores, inter alia: the risks to which workers are exposed; the legal aspects; relevant literature regarding medical surveillance, and the use of a medical surveillance instrument used to determine the health status of 142 construction workers who consented to participate in the study. The methodological approach used in this study was a quantitative descriptive design, more specifically, using a randomised cross-sectional survey design. The instrument used to determine health status included a full medical, occupational and social history, as well as a physical examination undertaken by Occupational Health Nursing Practitioners (OHNs). Findings indicate that most construction workers believe they are healthy. However only a small percentage of construction workers did not require referral for further investigation and / or treatment.
- Full Text:
The immobilization of Microcystis aeruginosa PCC7806 on a membrane nutrient-gradostat bioreacator for the production of the secondary metobolites
- Authors: Strong, Peter James
- Date: 2002
- Subjects: Microcystis aeruginosa , Myrocystins , Bioreactors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11083 , http://hdl.handle.net/10948/283 , Microcystis aeruginosa , Myrocystins , Bioreactors
- Description: A module and an inoculation technique were developed that would allow for the efficient immobilization of Microcystis aeruginosa PCC7806 on a synthetic membrane. A variety of module types, membranes (ceramic, tubular polyethersulfone and externally skinless polyethersulfone capillary membrane), and methods of immobilization (adsorption, pressure filtration and a developed technique that involved drying a cell slurry on a membrane) were assessed. The morphological properties that affected the immobilization of Microcystis aeruginosa PCC7806, as well as the effects of immobilization upon cell morphology were assessed. Cells in the stationary growth phase, which had a well-developed extra-cellular polysaccharide layer and no gas vesicles, were optimal for immobilization. Microcystin production under immobilized conditions was assessed under different nitrate concentrations, light intensities, biofilm thickness and immobilization times. Additional work included assaying for Microcystin production of two airlift-grown cultures under a high light intensity and complete nutrient deprivation and the inoculation of a ceramic membrane. An immunological technique was used to elucidate where toxin production was greatest within a biofilm immobilized upon an externally skinless polyethersulfone capillary membrane. The externally skinless polyethersulfone capillary membrane was evaluated to assess homogeneity and the physical differences between membrane batches that led to the erratic, incomplete biofilm formation, as a biofilm of a constant thickness could not be immobilized. Microcystis aeruginosa PCC7806 was exposed to a variety of solvents in order to permeabilize the cyanobacteria, as that would have enabled a truly continuous extraction process for the metabolite. FDA hydrolysis had to be optimized in order to use it as an indicator of cell viability. In addition a single-step extraction of Microcystin was attempted using live bacteria. A capillary membrane module, containing the externally skinless polyethersulfone capillary membrane, inoculated using pressure filtration, was the most efficient combination to establish a biofilm. Cells that were no longer actively dividing and that lacked buoyancy displayed superior immobilization to cells that were actively dividing and buoyant. The immobilized cells did produce Microcystin but in much lower concentrations to cells grown in an airlift culture. Biofilms grown with a higher nitrate concentration, a lower biofilm thickness and a lower light intensity had a higher specific microcystin content, while biofilms with a higher nitrate concentration a lower light intensity and a longer growth period displayed the a greater toxin production per mm2 of membrane. Microcystin occurred at its highest concentration in cells just above the pore opening. The diffusion of nutrients occurred relatively quickly to the outside layers of the biofilm, with a true gradient being established laterally from these nutrient veins that were above the pores. Permeabilization of the cells proved unsuccessful, as cells that remained viable did not release the intracellular compound into the surrounding medium.
- Full Text:
- Date Issued: 2002
- Authors: Strong, Peter James
- Date: 2002
- Subjects: Microcystis aeruginosa , Myrocystins , Bioreactors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11083 , http://hdl.handle.net/10948/283 , Microcystis aeruginosa , Myrocystins , Bioreactors
- Description: A module and an inoculation technique were developed that would allow for the efficient immobilization of Microcystis aeruginosa PCC7806 on a synthetic membrane. A variety of module types, membranes (ceramic, tubular polyethersulfone and externally skinless polyethersulfone capillary membrane), and methods of immobilization (adsorption, pressure filtration and a developed technique that involved drying a cell slurry on a membrane) were assessed. The morphological properties that affected the immobilization of Microcystis aeruginosa PCC7806, as well as the effects of immobilization upon cell morphology were assessed. Cells in the stationary growth phase, which had a well-developed extra-cellular polysaccharide layer and no gas vesicles, were optimal for immobilization. Microcystin production under immobilized conditions was assessed under different nitrate concentrations, light intensities, biofilm thickness and immobilization times. Additional work included assaying for Microcystin production of two airlift-grown cultures under a high light intensity and complete nutrient deprivation and the inoculation of a ceramic membrane. An immunological technique was used to elucidate where toxin production was greatest within a biofilm immobilized upon an externally skinless polyethersulfone capillary membrane. The externally skinless polyethersulfone capillary membrane was evaluated to assess homogeneity and the physical differences between membrane batches that led to the erratic, incomplete biofilm formation, as a biofilm of a constant thickness could not be immobilized. Microcystis aeruginosa PCC7806 was exposed to a variety of solvents in order to permeabilize the cyanobacteria, as that would have enabled a truly continuous extraction process for the metabolite. FDA hydrolysis had to be optimized in order to use it as an indicator of cell viability. In addition a single-step extraction of Microcystin was attempted using live bacteria. A capillary membrane module, containing the externally skinless polyethersulfone capillary membrane, inoculated using pressure filtration, was the most efficient combination to establish a biofilm. Cells that were no longer actively dividing and that lacked buoyancy displayed superior immobilization to cells that were actively dividing and buoyant. The immobilized cells did produce Microcystin but in much lower concentrations to cells grown in an airlift culture. Biofilms grown with a higher nitrate concentration, a lower biofilm thickness and a lower light intensity had a higher specific microcystin content, while biofilms with a higher nitrate concentration a lower light intensity and a longer growth period displayed the a greater toxin production per mm2 of membrane. Microcystin occurred at its highest concentration in cells just above the pore opening. The diffusion of nutrients occurred relatively quickly to the outside layers of the biofilm, with a true gradient being established laterally from these nutrient veins that were above the pores. Permeabilization of the cells proved unsuccessful, as cells that remained viable did not release the intracellular compound into the surrounding medium.
- Full Text:
- Date Issued: 2002
The influence of an adapted knee angle, as determined by isokinetic assessment, on sprint starting performance
- Authors: Schultz, Adrian Brent
- Date: 2004
- Subjects: Sprinting -- South Africa -- Physiological aspects -- Testing , Muscle strength -- Testing , Runners (Sports) -- South Africa -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11029 , http://hdl.handle.net/10948/317 , Sprinting -- South Africa -- Physiological aspects -- Testing , Muscle strength -- Testing , Runners (Sports) -- South Africa -- Testing
- Description: Muscle strength has been identified as an important contributor to athletic performance. Little attention however, has been paid to the specific relationship between peak isokinetic muscle strength and sprint starting performance. The aim of this study was to determine the influence of an adapted front knee angle, as determined by isokinetic assessment (the angle of peak torque production), on starting performance. Sixteen track sprinters, of elite-national or competitive-regional standard, were asked to perform eight sprints over 50m using four separate starting techniques. Technique 1 featured the athlete’s usual starting preferences while Techniques 2, 3 and 4 featured a standardised set of starting preferences with experimental modifications of the front knee angle in the “set” position. Isokinetic muscle strength was measured at slow (60°/s) and fast (240°/s) test speeds in order to determine the angle of peak torque production for concentric knee extension of each subject’s lead leg. Using one-way analysis of variance (ANOVA) and Post Hoc analysis (LSD), no significant differences (p>0.05) were observed between the experimental techniques for: block time, force-time measures during block time, sprint times, sprint velocity and acceleratio n measures at intervals up to 50m. Significant differences (p<0.05) were however observed between reaction times for the experimental techniques. Slower reaction times are most likely due to increased upper body pretension, resulting from the increased hip elevation seen for these techniques. The results indicate that increased hip elevation may have delayed the initiation of the relevant motor response required to affect an optimal sprint start. Technique 1 resulted in the shortest reaction times, shortest block times, fastest sprint times and greatest sprint velocities for all four techniques. This result was possibly due to the athlete’s experience with, and repeated use of, this technique. The experimental techniques therefore provided no added advantage over the subject’s preferred starting technique and did not significantly optimise sprint starting performance. The results show that modification of the front knee angle had no significant influence on sprint starting performance and sprint running ve locity or acceleration patterns up to 50m. Using Pearson’s Correlation Coefficient to determine the strongest correlations between isokinetic knee strength and sprint starting performance, analysis revealed that the strongest relationships were found between sprint starting performance expressed as acceleration and isokinetic knee strength expressed as relative peak torque and absolute peak torque. For Technique 1 the strongest correlation was found between acceleration (30m - 40m) and relative peak torque as measured at a test speed of 240°/s (r = 0.62). For the remaining experimental techniques, the strongest correlation was found between acceleration (10m - 20m) and relative peak torque as measured at a test speed of 60°/s (r = 0.53) for Technique 2, between acceleration (40m - 50m) and peak torque measured at a test speed of 60°/s (r = 0.72) for Technique 3, and between acceleration (0m - 5m) and peak torque as measured at a test speed of 240°/s (r = 0.71) for Technique 4. These results suggest that isokinetic muscle strength does not correlate strongly with sprint starting performance and that additional factors, such as neuromuscular organisation and muscle fibre typing, possibly make a greater contribution to optimal sprint starting performance.
- Full Text:
- Date Issued: 2004
- Authors: Schultz, Adrian Brent
- Date: 2004
- Subjects: Sprinting -- South Africa -- Physiological aspects -- Testing , Muscle strength -- Testing , Runners (Sports) -- South Africa -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11029 , http://hdl.handle.net/10948/317 , Sprinting -- South Africa -- Physiological aspects -- Testing , Muscle strength -- Testing , Runners (Sports) -- South Africa -- Testing
- Description: Muscle strength has been identified as an important contributor to athletic performance. Little attention however, has been paid to the specific relationship between peak isokinetic muscle strength and sprint starting performance. The aim of this study was to determine the influence of an adapted front knee angle, as determined by isokinetic assessment (the angle of peak torque production), on starting performance. Sixteen track sprinters, of elite-national or competitive-regional standard, were asked to perform eight sprints over 50m using four separate starting techniques. Technique 1 featured the athlete’s usual starting preferences while Techniques 2, 3 and 4 featured a standardised set of starting preferences with experimental modifications of the front knee angle in the “set” position. Isokinetic muscle strength was measured at slow (60°/s) and fast (240°/s) test speeds in order to determine the angle of peak torque production for concentric knee extension of each subject’s lead leg. Using one-way analysis of variance (ANOVA) and Post Hoc analysis (LSD), no significant differences (p>0.05) were observed between the experimental techniques for: block time, force-time measures during block time, sprint times, sprint velocity and acceleratio n measures at intervals up to 50m. Significant differences (p<0.05) were however observed between reaction times for the experimental techniques. Slower reaction times are most likely due to increased upper body pretension, resulting from the increased hip elevation seen for these techniques. The results indicate that increased hip elevation may have delayed the initiation of the relevant motor response required to affect an optimal sprint start. Technique 1 resulted in the shortest reaction times, shortest block times, fastest sprint times and greatest sprint velocities for all four techniques. This result was possibly due to the athlete’s experience with, and repeated use of, this technique. The experimental techniques therefore provided no added advantage over the subject’s preferred starting technique and did not significantly optimise sprint starting performance. The results show that modification of the front knee angle had no significant influence on sprint starting performance and sprint running ve locity or acceleration patterns up to 50m. Using Pearson’s Correlation Coefficient to determine the strongest correlations between isokinetic knee strength and sprint starting performance, analysis revealed that the strongest relationships were found between sprint starting performance expressed as acceleration and isokinetic knee strength expressed as relative peak torque and absolute peak torque. For Technique 1 the strongest correlation was found between acceleration (30m - 40m) and relative peak torque as measured at a test speed of 240°/s (r = 0.62). For the remaining experimental techniques, the strongest correlation was found between acceleration (10m - 20m) and relative peak torque as measured at a test speed of 60°/s (r = 0.53) for Technique 2, between acceleration (40m - 50m) and peak torque measured at a test speed of 60°/s (r = 0.72) for Technique 3, and between acceleration (0m - 5m) and peak torque as measured at a test speed of 240°/s (r = 0.71) for Technique 4. These results suggest that isokinetic muscle strength does not correlate strongly with sprint starting performance and that additional factors, such as neuromuscular organisation and muscle fibre typing, possibly make a greater contribution to optimal sprint starting performance.
- Full Text:
- Date Issued: 2004
The isolation and partial characterization of a2-antiplasmin and plasminogen from ostrich plasma
- Authors: Thomas, Adele René
- Date: 2000
- Subjects: Serpins , Ostriches , Antifibrinolytic agents , Plasminogen , Plasmin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11080 , http://hdl.handle.net/10948/274 , http://hdl.handle.net/10948/d1005751 , Serpins , Ostriches , Antifibrinolytic agents , Plasminogen , Plasmin
- Description: This study reports the isolation, purification and partial characterisation of the ostrich serpin, a2AP, as well as its target enzyme, ostrich plasmin, in its active and inactive proenzyme, viz. plasminogen, forms. Three different procedures were undertaken to isolate and purify ostrich a2AP. The first one involved L-lysine-Sepharose chromatography, ammonium sulfate fractionation, ion-exchange chromatography on Toyopearl Super-Q 650S, and ostrich plasminogen-Sepharose affinity chromatography. The second procedure replaced the latter chromatographic step with gel filtration on Sephadex G-200 and hydroxylapatite chromatography, while the third one employed instead the theoretically more efficient LBSI-Sepharose chromatographic step. The third procedure yielded purified ostrich a2AP, but the degree of purity and yield were relatively low. Ostrich plasminogen was highly purified after L-lysine-Sepharose chromatography and ostrich plasmin was obtained by the urokinase-activation of the purified ostrich plasminogen Ostrich a2AP revealed an Mr of 77-84 K and two isoelectric forms of pI 3.85 and 6.18. Nterminal sequence analysis showed ostrich a2AP to have only 2 out of 11 residues in common with both those of human and bovine a2AP. Ostrich a2AP showed the largest inhibitory effects on ostrich plasmin, followed by comm. bovine chymotrypsin, trypsin and plasmin, in that order, and it appeared to be a much less potent plasmin inhibitor than bovine aprotinin, but a much more potent one than the synthetic inhibitors, DFP and EACA. Ostrich plasminogen showed an Mr of 92 K and multiple isoelectric forms (~7) in the pI range 6.01-9.18, with a major one of pI 6.01. It showed a total of 775 amino acid residues and its N-terminal sequence showed ~53 percent identity with those of human, rabbit, cat, and ox plasminogens. Ostrich plasmin revealed an Mr of 78 K, two isoelectric forms of pI 4.07 and 6.01, and a total of 638 amino acid residues. N-terminal sequence analysis showed that 2-4 residues are identical to the 5 of human, cat, dog, rabbit, and ox plasmins. The pH and temperature optima of ostrich plasmin were determined as 8.0 and 40 oC, respectively. The thermodynamic and kinetic parameters of ostrich plasmin were computed, and plasmin was shown to prefer Lys to Arg residues in the S1 position. In conclusion, ostrich a2AP, plasminogen and plasmin showed definite similarities to their mammalian counterparts, but there were also significant differences.
- Full Text:
- Date Issued: 2000
- Authors: Thomas, Adele René
- Date: 2000
- Subjects: Serpins , Ostriches , Antifibrinolytic agents , Plasminogen , Plasmin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11080 , http://hdl.handle.net/10948/274 , http://hdl.handle.net/10948/d1005751 , Serpins , Ostriches , Antifibrinolytic agents , Plasminogen , Plasmin
- Description: This study reports the isolation, purification and partial characterisation of the ostrich serpin, a2AP, as well as its target enzyme, ostrich plasmin, in its active and inactive proenzyme, viz. plasminogen, forms. Three different procedures were undertaken to isolate and purify ostrich a2AP. The first one involved L-lysine-Sepharose chromatography, ammonium sulfate fractionation, ion-exchange chromatography on Toyopearl Super-Q 650S, and ostrich plasminogen-Sepharose affinity chromatography. The second procedure replaced the latter chromatographic step with gel filtration on Sephadex G-200 and hydroxylapatite chromatography, while the third one employed instead the theoretically more efficient LBSI-Sepharose chromatographic step. The third procedure yielded purified ostrich a2AP, but the degree of purity and yield were relatively low. Ostrich plasminogen was highly purified after L-lysine-Sepharose chromatography and ostrich plasmin was obtained by the urokinase-activation of the purified ostrich plasminogen Ostrich a2AP revealed an Mr of 77-84 K and two isoelectric forms of pI 3.85 and 6.18. Nterminal sequence analysis showed ostrich a2AP to have only 2 out of 11 residues in common with both those of human and bovine a2AP. Ostrich a2AP showed the largest inhibitory effects on ostrich plasmin, followed by comm. bovine chymotrypsin, trypsin and plasmin, in that order, and it appeared to be a much less potent plasmin inhibitor than bovine aprotinin, but a much more potent one than the synthetic inhibitors, DFP and EACA. Ostrich plasminogen showed an Mr of 92 K and multiple isoelectric forms (~7) in the pI range 6.01-9.18, with a major one of pI 6.01. It showed a total of 775 amino acid residues and its N-terminal sequence showed ~53 percent identity with those of human, rabbit, cat, and ox plasminogens. Ostrich plasmin revealed an Mr of 78 K, two isoelectric forms of pI 4.07 and 6.01, and a total of 638 amino acid residues. N-terminal sequence analysis showed that 2-4 residues are identical to the 5 of human, cat, dog, rabbit, and ox plasmins. The pH and temperature optima of ostrich plasmin were determined as 8.0 and 40 oC, respectively. The thermodynamic and kinetic parameters of ostrich plasmin were computed, and plasmin was shown to prefer Lys to Arg residues in the S1 position. In conclusion, ostrich a2AP, plasminogen and plasmin showed definite similarities to their mammalian counterparts, but there were also significant differences.
- Full Text:
- Date Issued: 2000
The labour law consequences of a transfer of a business
- Authors: Abader, Mogamad Shahied
- Date: 2003
- Subjects: Labor laws and legislation -- South Africa , Business enterprises -- Registration and transfer -- South Africa , Labor contract -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11057 , http://hdl.handle.net/10948/306 , Labor laws and legislation -- South Africa , Business enterprises -- Registration and transfer -- South Africa , Labor contract -- South Africa
- Description: The burden that South African labour law has to bear in relation to the economy is very heavy by international standards. In most industrially developed countries, the economy is strong enough either to provide jobs for most work-seekers or, failing that, an adequate social security system for households without breadwinners in place. In most developing countries with high unemployment rates, the labour law system makes only perfunctory effort to reach out to those facing economic marginalisation. South Africa, essentially a developing country, is not like that. The legal system is strong, works off a firm human rights base, and sets out to grapple with the issues. That is how it should be, but it comes at a price – an oftengraphic exposure of the limits of the law in a stressed society. Businesses operate for profit and survival according to the unsentimental ways of the market, and employees back in a bid to save jobs, lifestyles and livelihoods. The stakeholders use power when they have it, and make claims on the law when they don’t. The legislation and the case law reflect, add to and, to a degree, shape the complexities of these contests, and no more so than in the area of business restructuring.1 The new South Africa has quickly become the destination for foreign investment. The weakness of the rand against the dollar, pound, euro and with the “cost to sell and produce” being so low against these currencies, players on the corporate stage constantly change their make-up and composition. The larger engulfs the smaller, one company buys shares in another, or buys it out entirely, or all or part of its assets, and others are liquidated. In all these situations, employees in South Africa may find themselves with new bosses on the morning after. Under common law employees in this situation were deemed to have been discharged by the former employer, whether or not they have been offered positions in the transformed structure. If they did not want to work under it, they could not be forced to do so. That was because an employment contract was deemed in law to be one of a personal nature that could not be transferred from one employer to another without the employees consent. This research is conducted at an interesting time, when the amendments to the Labour Relations Act 66 of 1995 in respect of the transfer of a business, and in particular section 197, dealing with such matters comes into effect. It is also interesting in the sense that most judgements of the Commission for Conciliation, Mediation and Arbitration (CCMA) and judgements of the Labour Court were moving more or less to a common approach or interpretation of section 197 of the Labour Relations Act 66 of 1995 (hereinafter “the LRA”). Section 197 of the LRA sought to regulate the transfer of a business as a going concern and altered the common law regarding the transfer of a business in two situations – firstly when there is no insolvency, factual or legal, concerned, and secondly in the instance where the transferor is insolvent. The first extreme was when an employer is declared insolvent and the contracts of employment terminated automatically. The second extreme was from the first whereby the employer has to terminate the services of his employees and be liable to pay severance pay in terms of section 1893 of the LRA, which has also been amended along with section 197 of the LRA. It is as if this section was introduced to remedy these extremes. These extremes will be dealt with in detail in this paper. The transfer of goodwill and assets from the seller to the buyer occurs when a business is sold as a going concern. At common law the employees of a business cannot be transferred in the same manner. The Labour Relations Act 66 of 1995 altered this position. By enacting this section the legislature wanted to protect the interest of the employees in such transactions. Whether the legislature has succeeded or not is a matter that will be dealt with in this paper. It is all dependent on the interpretation of this section by the commissioners and judges. By including section 197 in the LRA, the legislature’s intention was to resolve the common law problem where employment contract terminated upon the sale of a business, and this section was intended to be an effective tool for protecting the employment of employees. In order to understand the labour law consequences of the transfer of a business, it is important to understand the provisions of sections 197 and 197A of the Labour Relations Amendment Act 2002. This will be dealt with and each section will be discussed in detail using relevant case law and literature. In considering investing in a South African based company by way of purchasing a share of the company and giving it your own flavour, one has to carefully consider the effects of this transaction. Companies wishing to restructure, outsource, merge or transfer some of its operations will need to understand what the implications of the labour legislation will have on their commercial rationale. Section 197 regulates the employment consequences when a transfer of a business takes place. This is defined to mean the transfer of a business by one employer (the old employer) to another employer (the new employer) as a going concern. Business is defined to include the whole or part of the business, trade undertaking or service. Like the current provision, the new provision referrers to the transfer of a business. It is therefore a wider concept than the sale of a business.4 No attempt is made to define what constitutes a going concern and the controversial issue of whether an outsourcing exercise can constitute a going concern transfer is also not explicitly dealt with. The fact that a business is defined to include a service may be an indication that it was intended to typify outsourcing as a going concern transfer, but this is not necessarily the case.5 The amendments to the Act6 came into effect on 1 August 2002. Sections 197 and 197(A) of the Act consequently seeks to regulate the transfer of a business. These regulations will be dealt with individually and in a format that would make each of the sections in sections 197 and 197(A), easy to understand and interpret. It will also become clear as to what the implications of each of the subsections will have on that commercial rationale. The issues highlighted above will be dealt with detail in this paper giving an overview of the Common Law, the Labour Relations Act 66 of 1995 and the new Labour Relations Amendment Act 2002.
- Full Text:
- Date Issued: 2003
- Authors: Abader, Mogamad Shahied
- Date: 2003
- Subjects: Labor laws and legislation -- South Africa , Business enterprises -- Registration and transfer -- South Africa , Labor contract -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11057 , http://hdl.handle.net/10948/306 , Labor laws and legislation -- South Africa , Business enterprises -- Registration and transfer -- South Africa , Labor contract -- South Africa
- Description: The burden that South African labour law has to bear in relation to the economy is very heavy by international standards. In most industrially developed countries, the economy is strong enough either to provide jobs for most work-seekers or, failing that, an adequate social security system for households without breadwinners in place. In most developing countries with high unemployment rates, the labour law system makes only perfunctory effort to reach out to those facing economic marginalisation. South Africa, essentially a developing country, is not like that. The legal system is strong, works off a firm human rights base, and sets out to grapple with the issues. That is how it should be, but it comes at a price – an oftengraphic exposure of the limits of the law in a stressed society. Businesses operate for profit and survival according to the unsentimental ways of the market, and employees back in a bid to save jobs, lifestyles and livelihoods. The stakeholders use power when they have it, and make claims on the law when they don’t. The legislation and the case law reflect, add to and, to a degree, shape the complexities of these contests, and no more so than in the area of business restructuring.1 The new South Africa has quickly become the destination for foreign investment. The weakness of the rand against the dollar, pound, euro and with the “cost to sell and produce” being so low against these currencies, players on the corporate stage constantly change their make-up and composition. The larger engulfs the smaller, one company buys shares in another, or buys it out entirely, or all or part of its assets, and others are liquidated. In all these situations, employees in South Africa may find themselves with new bosses on the morning after. Under common law employees in this situation were deemed to have been discharged by the former employer, whether or not they have been offered positions in the transformed structure. If they did not want to work under it, they could not be forced to do so. That was because an employment contract was deemed in law to be one of a personal nature that could not be transferred from one employer to another without the employees consent. This research is conducted at an interesting time, when the amendments to the Labour Relations Act 66 of 1995 in respect of the transfer of a business, and in particular section 197, dealing with such matters comes into effect. It is also interesting in the sense that most judgements of the Commission for Conciliation, Mediation and Arbitration (CCMA) and judgements of the Labour Court were moving more or less to a common approach or interpretation of section 197 of the Labour Relations Act 66 of 1995 (hereinafter “the LRA”). Section 197 of the LRA sought to regulate the transfer of a business as a going concern and altered the common law regarding the transfer of a business in two situations – firstly when there is no insolvency, factual or legal, concerned, and secondly in the instance where the transferor is insolvent. The first extreme was when an employer is declared insolvent and the contracts of employment terminated automatically. The second extreme was from the first whereby the employer has to terminate the services of his employees and be liable to pay severance pay in terms of section 1893 of the LRA, which has also been amended along with section 197 of the LRA. It is as if this section was introduced to remedy these extremes. These extremes will be dealt with in detail in this paper. The transfer of goodwill and assets from the seller to the buyer occurs when a business is sold as a going concern. At common law the employees of a business cannot be transferred in the same manner. The Labour Relations Act 66 of 1995 altered this position. By enacting this section the legislature wanted to protect the interest of the employees in such transactions. Whether the legislature has succeeded or not is a matter that will be dealt with in this paper. It is all dependent on the interpretation of this section by the commissioners and judges. By including section 197 in the LRA, the legislature’s intention was to resolve the common law problem where employment contract terminated upon the sale of a business, and this section was intended to be an effective tool for protecting the employment of employees. In order to understand the labour law consequences of the transfer of a business, it is important to understand the provisions of sections 197 and 197A of the Labour Relations Amendment Act 2002. This will be dealt with and each section will be discussed in detail using relevant case law and literature. In considering investing in a South African based company by way of purchasing a share of the company and giving it your own flavour, one has to carefully consider the effects of this transaction. Companies wishing to restructure, outsource, merge or transfer some of its operations will need to understand what the implications of the labour legislation will have on their commercial rationale. Section 197 regulates the employment consequences when a transfer of a business takes place. This is defined to mean the transfer of a business by one employer (the old employer) to another employer (the new employer) as a going concern. Business is defined to include the whole or part of the business, trade undertaking or service. Like the current provision, the new provision referrers to the transfer of a business. It is therefore a wider concept than the sale of a business.4 No attempt is made to define what constitutes a going concern and the controversial issue of whether an outsourcing exercise can constitute a going concern transfer is also not explicitly dealt with. The fact that a business is defined to include a service may be an indication that it was intended to typify outsourcing as a going concern transfer, but this is not necessarily the case.5 The amendments to the Act6 came into effect on 1 August 2002. Sections 197 and 197(A) of the Act consequently seeks to regulate the transfer of a business. These regulations will be dealt with individually and in a format that would make each of the sections in sections 197 and 197(A), easy to understand and interpret. It will also become clear as to what the implications of each of the subsections will have on that commercial rationale. The issues highlighted above will be dealt with detail in this paper giving an overview of the Common Law, the Labour Relations Act 66 of 1995 and the new Labour Relations Amendment Act 2002.
- Full Text:
- Date Issued: 2003
The law relating to lock-outs
- Madokwe, De Villiers Badanile
- Authors: Madokwe, De Villiers Badanile
- Date: 2003
- Subjects: Strikes and lockouts -- Law and legislation -- South Africa , Labor laws and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11046 , http://hdl.handle.net/10948/298 , Strikes and lockouts -- Law and legislation -- South Africa , Labor laws and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Description: The lock-out is accepted as a necessary element of collective bargaining. The law relating to lock-out is considered as a legitimate instrument of industrial action. There are a number of procedural requirements for a legal lock-out. The dispute should be referred to a bargaining council (or where there is no bargaining council with jurisdiction, to a statutory council) or, failing which, the Commission for Conciliation, Mediation and Arbitration. If the bargaining/statutory council or the commission fails to resolve the dispute, it is no longer required that a ballet should be brought out in favour of the contemplated lock-out before the lock-out could be legal: all that is required is that the period of notice of the intended lock-out is given. The lock-out may either be protected or unprotected. It is protected if it is not prohibited absolutely and the various procedural requirements have been complied with. The protected lock-out is immuned from civil liability. On the other hand a lockout will be unprotected if it does not comply with sections 64 and 65 of the Labour Relations Act, 1995. In the circumstances the Labour Court has exclusive jurisdiction to grant an interdict or order to restrain any person from participating in unprotected industrial action and to order the payment of just and equitable compensation for any loss attributable to the lock-out. Lock-outs are prohibited in specific instances and allowed with some qualifications in others. For example, employers engaged in the provision of essential or maintenance services are prohibited from locking their employees out in order compel them to comply with their demand. Such essential services are Parliamentary services, the South African Police Service and a service the interruption of which endangers the life, personal safety or health of the whole. A distinction is also drawn between offensive and defensive lock-outs. Defensive lock-outs involve the closure of an employer’s premises or the shutting down of its operations during industrial action initiated by workers. The offensive lock-outs, also known as “pre-emptive lock-outs”, amount to an employer initiated form of industrial iv action where the premises are locked and workers are excluded and prevented from working. The law relating to lock-out in South Africa is clearly put in its proper perspective by the interim Constitution of the Republic of South Africa 200 of 1993, final Constitution of the Republic of South Africa 108 of 1996, Labour Relations Act 66 of 1995 and in Ex Parte Chairperson of the Constitutional Assembly: In re Certification of the Constitution of the Republic of South Africa.1 However the situation is unsatisfactory to employers. The interim Constitution guaranteed the “right to strike” and “recourse to the lock-out”. Under the final Constitution lock-outs enjoy no direct protection. The Constitutional Court’s certification judgement rejects the view that it is necessary in order to maintain equality to entrench the right to lock-out once the right to strike has been included. The Constitutional Court concluded that the right to strike and the right to lock-out are not always and necessarily equivalent. However the purpose of the lock-out is to settle collective dispute of the ways permitted by the Labour Relations Act, 1995. The purpose is not to terminate the relationship between the employer and the employee. The employer may not, for example, dismiss employees finally at the end of an unsuccessful lock-out in order to avoid the consequences of impending strike action by the employees.
- Full Text:
- Date Issued: 2003
- Authors: Madokwe, De Villiers Badanile
- Date: 2003
- Subjects: Strikes and lockouts -- Law and legislation -- South Africa , Labor laws and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11046 , http://hdl.handle.net/10948/298 , Strikes and lockouts -- Law and legislation -- South Africa , Labor laws and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Description: The lock-out is accepted as a necessary element of collective bargaining. The law relating to lock-out is considered as a legitimate instrument of industrial action. There are a number of procedural requirements for a legal lock-out. The dispute should be referred to a bargaining council (or where there is no bargaining council with jurisdiction, to a statutory council) or, failing which, the Commission for Conciliation, Mediation and Arbitration. If the bargaining/statutory council or the commission fails to resolve the dispute, it is no longer required that a ballet should be brought out in favour of the contemplated lock-out before the lock-out could be legal: all that is required is that the period of notice of the intended lock-out is given. The lock-out may either be protected or unprotected. It is protected if it is not prohibited absolutely and the various procedural requirements have been complied with. The protected lock-out is immuned from civil liability. On the other hand a lockout will be unprotected if it does not comply with sections 64 and 65 of the Labour Relations Act, 1995. In the circumstances the Labour Court has exclusive jurisdiction to grant an interdict or order to restrain any person from participating in unprotected industrial action and to order the payment of just and equitable compensation for any loss attributable to the lock-out. Lock-outs are prohibited in specific instances and allowed with some qualifications in others. For example, employers engaged in the provision of essential or maintenance services are prohibited from locking their employees out in order compel them to comply with their demand. Such essential services are Parliamentary services, the South African Police Service and a service the interruption of which endangers the life, personal safety or health of the whole. A distinction is also drawn between offensive and defensive lock-outs. Defensive lock-outs involve the closure of an employer’s premises or the shutting down of its operations during industrial action initiated by workers. The offensive lock-outs, also known as “pre-emptive lock-outs”, amount to an employer initiated form of industrial iv action where the premises are locked and workers are excluded and prevented from working. The law relating to lock-out in South Africa is clearly put in its proper perspective by the interim Constitution of the Republic of South Africa 200 of 1993, final Constitution of the Republic of South Africa 108 of 1996, Labour Relations Act 66 of 1995 and in Ex Parte Chairperson of the Constitutional Assembly: In re Certification of the Constitution of the Republic of South Africa.1 However the situation is unsatisfactory to employers. The interim Constitution guaranteed the “right to strike” and “recourse to the lock-out”. Under the final Constitution lock-outs enjoy no direct protection. The Constitutional Court’s certification judgement rejects the view that it is necessary in order to maintain equality to entrench the right to lock-out once the right to strike has been included. The Constitutional Court concluded that the right to strike and the right to lock-out are not always and necessarily equivalent. However the purpose of the lock-out is to settle collective dispute of the ways permitted by the Labour Relations Act, 1995. The purpose is not to terminate the relationship between the employer and the employee. The employer may not, for example, dismiss employees finally at the end of an unsuccessful lock-out in order to avoid the consequences of impending strike action by the employees.
- Full Text:
- Date Issued: 2003
The law relating to retrenchment
- Authors: Van Staden, Leon
- Date: 2003
- Subjects: Employees -- Dismissal of -- Law and legislation -- South Africa , Downsizing of organizations -- Law and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11055 , http://hdl.handle.net/10948/304 , Employees -- Dismissal of -- Law and legislation -- South Africa , Downsizing of organizations -- Law and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Description: Retrenchment, as a form of dismissal, is regulated by section 189 and 189A of the Labour Relations Act 1995. In order for a retrenchment to be fair, it must comply with both the substantive and procedural requirements stipulated in the Act. After an employee has proved the dismissal, the onus rests on the employer to comply with these two requirements by providing proof thereof. One of the most important procedural requirements that must be complied with by the employer is that the employer cannot merely make a decision to retrench. This decision may only be made once the employer, when contemplating a retrenchment, followed the lengthy consultation process as required in section 189. Recent amendments to section 189 introduced a distinction between a small and big employer and further between a large-scale and small-scale dismissal. If the employee is of the opinion that the employer did not comply with either the procedural or substantive requirements or both, he/she may refer such a dispute for conciliation and thereafter for arbitration or adjudication, according to a dispute resolution process contained in the Act, during which process certain remedies are available to the dismissed employee. The Labour Relations Act 1995 also introduced important amendments which have the effect that employees are allowed to, in certain circumstances, to strike over collective retrenchment disputes.
- Full Text:
- Date Issued: 2003
- Authors: Van Staden, Leon
- Date: 2003
- Subjects: Employees -- Dismissal of -- Law and legislation -- South Africa , Downsizing of organizations -- Law and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11055 , http://hdl.handle.net/10948/304 , Employees -- Dismissal of -- Law and legislation -- South Africa , Downsizing of organizations -- Law and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Description: Retrenchment, as a form of dismissal, is regulated by section 189 and 189A of the Labour Relations Act 1995. In order for a retrenchment to be fair, it must comply with both the substantive and procedural requirements stipulated in the Act. After an employee has proved the dismissal, the onus rests on the employer to comply with these two requirements by providing proof thereof. One of the most important procedural requirements that must be complied with by the employer is that the employer cannot merely make a decision to retrench. This decision may only be made once the employer, when contemplating a retrenchment, followed the lengthy consultation process as required in section 189. Recent amendments to section 189 introduced a distinction between a small and big employer and further between a large-scale and small-scale dismissal. If the employee is of the opinion that the employer did not comply with either the procedural or substantive requirements or both, he/she may refer such a dispute for conciliation and thereafter for arbitration or adjudication, according to a dispute resolution process contained in the Act, during which process certain remedies are available to the dismissed employee. The Labour Relations Act 1995 also introduced important amendments which have the effect that employees are allowed to, in certain circumstances, to strike over collective retrenchment disputes.
- Full Text:
- Date Issued: 2003
The legal implications of rugby injuries
- Authors: Viljoen, Erna
- Date: 2003
- Subjects: Rugby football injuries -- South Africa , Sports medicine -- Law and legislation -- South Africa , Rugby football players -- Legal status, laws, etc. -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11058 , http://hdl.handle.net/10948/332 , Rugby football injuries -- South Africa , Sports medicine -- Law and legislation -- South Africa , Rugby football players -- Legal status, laws, etc. -- South Africa
- Description: Sports law in South Africa is a field requiring exciting and intensive research. With so many sporting codes changing their status to professional sport, intensive research on the legal implications pertaining to each professional sporting code has also become necessary. Professional rugby in South Africa has grown into a multimillion rand industry. It is an industry whose role players need specialized legal advice on a multitude of issues. This dissertation addresses the legal issues arising out of the situation where a professional player is injured, during practice or a game, due to the intentional or negligent action of another. The medico-legal aspects of rugby, relating to causation and proof of injuries are an indispensable element of proving liability where rugby injuries are concerned. These aspects are crucial in assessing the criminal and delictual liability of players, coaches, referees, team physicians and even the union concerned. The problem of rugby violence, causing injury, is addressed by both the criminal law and the law of delict with the issue of consent being central to this discussion. Furthermore, the labour law implications can be far-reaching for both the player and the employer union due to the unique features of sport as an industry. All role players in professional rugby will have to cooperate with the legal community to ensure that a practical body of law is established in order to make rugby a safer sport for all concerned and to protect the professional player from unnecessary, incapacitating injury.
- Full Text:
- Date Issued: 2003
- Authors: Viljoen, Erna
- Date: 2003
- Subjects: Rugby football injuries -- South Africa , Sports medicine -- Law and legislation -- South Africa , Rugby football players -- Legal status, laws, etc. -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11058 , http://hdl.handle.net/10948/332 , Rugby football injuries -- South Africa , Sports medicine -- Law and legislation -- South Africa , Rugby football players -- Legal status, laws, etc. -- South Africa
- Description: Sports law in South Africa is a field requiring exciting and intensive research. With so many sporting codes changing their status to professional sport, intensive research on the legal implications pertaining to each professional sporting code has also become necessary. Professional rugby in South Africa has grown into a multimillion rand industry. It is an industry whose role players need specialized legal advice on a multitude of issues. This dissertation addresses the legal issues arising out of the situation where a professional player is injured, during practice or a game, due to the intentional or negligent action of another. The medico-legal aspects of rugby, relating to causation and proof of injuries are an indispensable element of proving liability where rugby injuries are concerned. These aspects are crucial in assessing the criminal and delictual liability of players, coaches, referees, team physicians and even the union concerned. The problem of rugby violence, causing injury, is addressed by both the criminal law and the law of delict with the issue of consent being central to this discussion. Furthermore, the labour law implications can be far-reaching for both the player and the employer union due to the unique features of sport as an industry. All role players in professional rugby will have to cooperate with the legal community to ensure that a practical body of law is established in order to make rugby a safer sport for all concerned and to protect the professional player from unnecessary, incapacitating injury.
- Full Text:
- Date Issued: 2003
The medicinal chemistry of the isomers of the cyclic dipeptide: cyclo(Trp-Pro)
- Authors: Jamie, Hajierah
- Date: 2002
- Subjects: Pharmaceutical chemistry , Cyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11023 , http://hdl.handle.net/10948/281 , Pharmaceutical chemistry , Cyclic compounds
- Description: The isomers of cyclo(Trp-Pro) (cyclo(L-Trp-L-Pro), cyclo(L-Trp-D-Pro), cyclo(D-Trp-LPro) and cyclo(D-Trp-D-Pro)) have been successfully synthesized and screened for biological activity. High percentage yields were obtained by using the three phase synthesis system, which involves the synthesis of the intermediate protected linear dipeptides, followed by the removal of the protecting Boc groups. This step is followed by cyclization and crystallization of the isomers. The diketopiperazines rings of cyclo(L-Trp-L-Pro) and cyclo(D-Trp-D-Pro) contain cisamide bonds, while cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) contain trans-amide bonds. These bonds govern the conformation of the diketopiperazines ring. The isomers have shown different degrees of biological activity, possibly as a result of the orientation of the side chain of tryptophan and this difference in conformation, leading to varying interactions between isomer and a range of receptors. Under experimental conditions, 10-3 M cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) showed effective anticancer activity against the cervical cancer cell line, HeLa, resulting in a <50% reduction in cell viability. Cytotoxicity screening with cyclo(D-Trp-L-Pro) indicated that it was hepatocyte-specific in its toxicity, whilst the other isomers were cytotoxic against the other cell types tested. At 1mg/ml, cyclo(L-Trp-L-Pro) proved to be an effective antimicrobial agent against Gram positive bacteria, while cyclo(L-Trp-DPro) effectively inhibited the growth of the Gram negative bacteria, Esherichia coli. Cyclo(D-Trp-L-Pro) proved to be effective against Streptococcus, while cyclo(D-Trp-DPro) effectively reduced viability of the yeast, Candida albicans. Cyclo(D-Trp-L-Pro) was the only isomer to show Ca2+-channel antagonism, whilst the other isomers resulted in opening of the Ca2+-channel. No effects were observed on K+-channel activity for all the isomers tested. The isomers also proved to be valuable antiarrhythmic agents by effectively reducing the time spent in ventricular tachycardia and arrhythmia, as well as decreasing the time for the heart rate to return to a normal sinus rhythm. Furthermore, cyclo(L-Trp-D-Pro) showed positive chronotropic activity, while cyclo(D-Trp-L-Pro) ii showed negative chronotropic activity. In addition, cyclo(L-Trp-D-Pro) and cyclo(D-Trp- L-Pro) also increased the coronary flow rate. 0.125 1 mM Cyclo(L-Trp-D-Pro) decreased aggregation in washed platelets induced by thrombin. All isomers increased adhesion to an artificial surface when the platelets were stimulated by ADP, yet caused reduced adhesion when the platelets were stimulated by thrombin. These results prove the potential of these compounds as novel agents in a range of biological fields, indicating that a combination of L- and D- amino acids may prove more effective than an agent consisting solely of L-amino acids.
- Full Text:
- Date Issued: 2002
- Authors: Jamie, Hajierah
- Date: 2002
- Subjects: Pharmaceutical chemistry , Cyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11023 , http://hdl.handle.net/10948/281 , Pharmaceutical chemistry , Cyclic compounds
- Description: The isomers of cyclo(Trp-Pro) (cyclo(L-Trp-L-Pro), cyclo(L-Trp-D-Pro), cyclo(D-Trp-LPro) and cyclo(D-Trp-D-Pro)) have been successfully synthesized and screened for biological activity. High percentage yields were obtained by using the three phase synthesis system, which involves the synthesis of the intermediate protected linear dipeptides, followed by the removal of the protecting Boc groups. This step is followed by cyclization and crystallization of the isomers. The diketopiperazines rings of cyclo(L-Trp-L-Pro) and cyclo(D-Trp-D-Pro) contain cisamide bonds, while cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) contain trans-amide bonds. These bonds govern the conformation of the diketopiperazines ring. The isomers have shown different degrees of biological activity, possibly as a result of the orientation of the side chain of tryptophan and this difference in conformation, leading to varying interactions between isomer and a range of receptors. Under experimental conditions, 10-3 M cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) showed effective anticancer activity against the cervical cancer cell line, HeLa, resulting in a <50% reduction in cell viability. Cytotoxicity screening with cyclo(D-Trp-L-Pro) indicated that it was hepatocyte-specific in its toxicity, whilst the other isomers were cytotoxic against the other cell types tested. At 1mg/ml, cyclo(L-Trp-L-Pro) proved to be an effective antimicrobial agent against Gram positive bacteria, while cyclo(L-Trp-DPro) effectively inhibited the growth of the Gram negative bacteria, Esherichia coli. Cyclo(D-Trp-L-Pro) proved to be effective against Streptococcus, while cyclo(D-Trp-DPro) effectively reduced viability of the yeast, Candida albicans. Cyclo(D-Trp-L-Pro) was the only isomer to show Ca2+-channel antagonism, whilst the other isomers resulted in opening of the Ca2+-channel. No effects were observed on K+-channel activity for all the isomers tested. The isomers also proved to be valuable antiarrhythmic agents by effectively reducing the time spent in ventricular tachycardia and arrhythmia, as well as decreasing the time for the heart rate to return to a normal sinus rhythm. Furthermore, cyclo(L-Trp-D-Pro) showed positive chronotropic activity, while cyclo(D-Trp-L-Pro) ii showed negative chronotropic activity. In addition, cyclo(L-Trp-D-Pro) and cyclo(D-Trp- L-Pro) also increased the coronary flow rate. 0.125 1 mM Cyclo(L-Trp-D-Pro) decreased aggregation in washed platelets induced by thrombin. All isomers increased adhesion to an artificial surface when the platelets were stimulated by ADP, yet caused reduced adhesion when the platelets were stimulated by thrombin. These results prove the potential of these compounds as novel agents in a range of biological fields, indicating that a combination of L- and D- amino acids may prove more effective than an agent consisting solely of L-amino acids.
- Full Text:
- Date Issued: 2002
The nature and potential effect of the Labour Relations Amendment Act 2002
- Authors: Conroy, Andrew Geddes
- Date: 2003
- Subjects: South Africa. Labour Relations Amendment Act 2002 , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11037 , http://hdl.handle.net/10948/292 , South Africa. Labour Relations Amendment Act 2002 , Labor laws and legislation -- South Africa
- Description: It took 18 months of intensive negotiation at the Millennium Labour Council, NEDLAC and the Labour Portfolio Committee before the Labour Relations Amendment Act of 20021 completed its passage through Parliament, taking effect on 1 August 2002. Fifty-seven amendments to specific sections of the Labour Relations Act2 and its schedules cure some obvious anomalies in the original version. It is further apparent that the legislature has taken cognisance of the observations by judges and arbitrators, who voiced their criticism in respect of certain aspects of the original "Act". The amended "Act"3 does appear to be a genuine commitment by both business and organised labour to improve efficiency in the labour market, to promote employment creation and to protect vulnerable workers. Improved dispute resolution mechanisms, enforcement mechanisms and the resurgence of an unfettered discretion in awarding compensation go some way to improving the application of the "Act". The most dramatic amendments have taken place in the law regulating retrenchments by large employers, inclusive of the controversial introduction of a right to strike after retrenchments of this nature have been effected, and the regulation of the transfer of a business as a going concern and its impact on workers. Critics indicate that business and organised labour have subscribed to the package of amendments despite respective reservations and due to certain time constraints. The nett result is a package of amendments that could be described as failing to address, in certain respects, or intentionally overlooking, areas of the "Act" that have traditionally been shown wanting in the past. In the individual employment law sphere specifically, the failure to address the meaning of "benefits" in the definition of unfair labour practices; to allocate a precise meaning to the concept of the transfer of a going concern; or to regulate the conduct of employers when transferring employees, remain some of the areas for concern. It appears that the legislature has decided that certain issues should be resolved by the Labour Court, and ultimately the Labour Appeal Court, on a case-by-case basis rather than by legislative intervention. Whilst this approach has merit, it does present problems to those seeking to apply the provisions of the amended "Act" 5 in everyday practice. On the whole, the amendments do not, nor were they designed to, mark a major shift in the government's labour market policy. The changes clearly focus on correcting and clarifying sections of the "Act", which have resulted in unintended consequences, or lost touch with commercial reality, over the past seven years.
- Full Text:
- Date Issued: 2003
- Authors: Conroy, Andrew Geddes
- Date: 2003
- Subjects: South Africa. Labour Relations Amendment Act 2002 , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11037 , http://hdl.handle.net/10948/292 , South Africa. Labour Relations Amendment Act 2002 , Labor laws and legislation -- South Africa
- Description: It took 18 months of intensive negotiation at the Millennium Labour Council, NEDLAC and the Labour Portfolio Committee before the Labour Relations Amendment Act of 20021 completed its passage through Parliament, taking effect on 1 August 2002. Fifty-seven amendments to specific sections of the Labour Relations Act2 and its schedules cure some obvious anomalies in the original version. It is further apparent that the legislature has taken cognisance of the observations by judges and arbitrators, who voiced their criticism in respect of certain aspects of the original "Act". The amended "Act"3 does appear to be a genuine commitment by both business and organised labour to improve efficiency in the labour market, to promote employment creation and to protect vulnerable workers. Improved dispute resolution mechanisms, enforcement mechanisms and the resurgence of an unfettered discretion in awarding compensation go some way to improving the application of the "Act". The most dramatic amendments have taken place in the law regulating retrenchments by large employers, inclusive of the controversial introduction of a right to strike after retrenchments of this nature have been effected, and the regulation of the transfer of a business as a going concern and its impact on workers. Critics indicate that business and organised labour have subscribed to the package of amendments despite respective reservations and due to certain time constraints. The nett result is a package of amendments that could be described as failing to address, in certain respects, or intentionally overlooking, areas of the "Act" that have traditionally been shown wanting in the past. In the individual employment law sphere specifically, the failure to address the meaning of "benefits" in the definition of unfair labour practices; to allocate a precise meaning to the concept of the transfer of a going concern; or to regulate the conduct of employers when transferring employees, remain some of the areas for concern. It appears that the legislature has decided that certain issues should be resolved by the Labour Court, and ultimately the Labour Appeal Court, on a case-by-case basis rather than by legislative intervention. Whilst this approach has merit, it does present problems to those seeking to apply the provisions of the amended "Act" 5 in everyday practice. On the whole, the amendments do not, nor were they designed to, mark a major shift in the government's labour market policy. The changes clearly focus on correcting and clarifying sections of the "Act", which have resulted in unintended consequences, or lost touch with commercial reality, over the past seven years.
- Full Text:
- Date Issued: 2003
The performance of children with autism on the Revised Extended Griffiths Scales of Mental Development
- Authors: Gowar, Rosemary Vera
- Date: 2004
- Subjects: Psychological tests for children -- South Africa , Autism in children -- South Africa , Children -- Intelligence testing -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11016 , http://hdl.handle.net/10948/353 , Psychological tests for children -- South Africa , Autism in children -- South Africa , Children -- Intelligence testing -- South Africa
- Description: Despite a widespread perception that the number of children coming to clinical attention with Autism Spectrum Disorders has greatly increased, limited South African Research has been conducted on children with Autism. Thus a need exists to accumulate knowledge about the cognitive, psychological and personalsocial growth of children diagnosed with Autism. This study is aimed at exploring the performance of children with Autism between the ages of 7 years (from 72 months) and 8 years (to 95.9 months), in South Africa (SA), utilising the Revised Extended Griffiths Scales of Mental Development (GSMD). The sample comprised an experimental group of 30 children with Autism from four schools for Specialised Education for learners with Autism in SA, and a control group comprised of 30 “normal” children, where normalcy can be broadly defined as “an absence of any sensory, physical or mental handicap”. The six areas of general development assessed included Locomotor, Personal- Social, Language, Eye and Hand co-ordination, Performance, and Practical Reasoning. A non-probability, purposive sampling method was applied. The major findings of the present study were as follows: (i) Children with Autism (years 7 & 8) showed a characteristic cognitive profile when tested with the revised Extended Griffiths Scales. Their performance indicates lower performance on Subcales B, C and F than on the other Subscales. (ii) Some children with Autism experienced major fall-outs, whereas others were slightly below average. The general performance of children with Autism was, however, in the range “cognitively impaired”. (iii) There was significant difference between the Autistic sample and the normal sample on the GQ. xiv In view of the findings, it is recommended that the results of the study, which focused on the children’s areas of developmental weakness, be widely disseminated. This could facilitate the development of therapeutic programmes, so as to allow for appropriate stimulation for children with Autism.
- Full Text:
- Date Issued: 2004
- Authors: Gowar, Rosemary Vera
- Date: 2004
- Subjects: Psychological tests for children -- South Africa , Autism in children -- South Africa , Children -- Intelligence testing -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11016 , http://hdl.handle.net/10948/353 , Psychological tests for children -- South Africa , Autism in children -- South Africa , Children -- Intelligence testing -- South Africa
- Description: Despite a widespread perception that the number of children coming to clinical attention with Autism Spectrum Disorders has greatly increased, limited South African Research has been conducted on children with Autism. Thus a need exists to accumulate knowledge about the cognitive, psychological and personalsocial growth of children diagnosed with Autism. This study is aimed at exploring the performance of children with Autism between the ages of 7 years (from 72 months) and 8 years (to 95.9 months), in South Africa (SA), utilising the Revised Extended Griffiths Scales of Mental Development (GSMD). The sample comprised an experimental group of 30 children with Autism from four schools for Specialised Education for learners with Autism in SA, and a control group comprised of 30 “normal” children, where normalcy can be broadly defined as “an absence of any sensory, physical or mental handicap”. The six areas of general development assessed included Locomotor, Personal- Social, Language, Eye and Hand co-ordination, Performance, and Practical Reasoning. A non-probability, purposive sampling method was applied. The major findings of the present study were as follows: (i) Children with Autism (years 7 & 8) showed a characteristic cognitive profile when tested with the revised Extended Griffiths Scales. Their performance indicates lower performance on Subcales B, C and F than on the other Subscales. (ii) Some children with Autism experienced major fall-outs, whereas others were slightly below average. The general performance of children with Autism was, however, in the range “cognitively impaired”. (iii) There was significant difference between the Autistic sample and the normal sample on the GQ. xiv In view of the findings, it is recommended that the results of the study, which focused on the children’s areas of developmental weakness, be widely disseminated. This could facilitate the development of therapeutic programmes, so as to allow for appropriate stimulation for children with Autism.
- Full Text:
- Date Issued: 2004
The performance of hearing impaired children on the Revised Extended Griffiths Scales
- Authors: Schröder, Ingrid Anita
- Date: 2004
- Subjects: Psychological tests for children -- South Africa , Griffiths Developmental Scales , Deaf children -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11031 , http://hdl.handle.net/10948/333 , Psychological tests for children -- South Africa , Griffiths Developmental Scales , Deaf children -- South Africa
- Description: In this unique time of nation building in South Africa, education is seen as the key foundation stone to prosperity and development. However, despite a decade of restructuring, many differing groups of children still do not receive the quality of education they deserve. Amongst those are children with special needs, including those who have a hearing impairment. These children are the focus of the present study. It is a widely accepted principle that early assessment and intervention is necessary to maximise a child’s potential. It is for this reason that the global aim of this study was to explore and describe the developmental profile of hearing impaired children on the Revised Extended Griffiths Scales. Further aims were to compare the performance of the clinical sample to a normal South African sample. A quantitative, exploratory-descriptive research design was employed. The sample of hearing impaired children (N = 58), between the ages of 36 and 95 months, attended the Carel du Toit Pre-School in the Western Cape, South Africa and were obtained by means of a non-probability, purposive sampling procedure. The normal sample (N = 58) was drawn from an existing database created for the revision of the Scales. Information was collated using clinical files, biographical data as well as the results of an assessment on the Revised Extended Griffiths Scales. The major findings of the study are summarised below. The general performance of the hearing impaired sample on the Revised Extended Griffiths Scales was average. The performance of the children on the six subscales ranged from below average to average, with major fall-outs occurring on the Hearing and Speech and Practical Reasoning Subscales. The normal sample performed significantly better than the hearing impaired sample on all of the subscales of the measure. However, significant differences were found on four of the six subscales, namely, the Locomotor, Personal-Social, Hearing and Speech and Practical Reasoning Subscales. Generally, the results of the current study suggest that a specific developmental profile is obtained for hearing impaired children. In addition, this study has highlighted the success with which the Revised Extended Griffiths Scales can be utilised on a hearing impaired population.
- Full Text:
- Date Issued: 2004
- Authors: Schröder, Ingrid Anita
- Date: 2004
- Subjects: Psychological tests for children -- South Africa , Griffiths Developmental Scales , Deaf children -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11031 , http://hdl.handle.net/10948/333 , Psychological tests for children -- South Africa , Griffiths Developmental Scales , Deaf children -- South Africa
- Description: In this unique time of nation building in South Africa, education is seen as the key foundation stone to prosperity and development. However, despite a decade of restructuring, many differing groups of children still do not receive the quality of education they deserve. Amongst those are children with special needs, including those who have a hearing impairment. These children are the focus of the present study. It is a widely accepted principle that early assessment and intervention is necessary to maximise a child’s potential. It is for this reason that the global aim of this study was to explore and describe the developmental profile of hearing impaired children on the Revised Extended Griffiths Scales. Further aims were to compare the performance of the clinical sample to a normal South African sample. A quantitative, exploratory-descriptive research design was employed. The sample of hearing impaired children (N = 58), between the ages of 36 and 95 months, attended the Carel du Toit Pre-School in the Western Cape, South Africa and were obtained by means of a non-probability, purposive sampling procedure. The normal sample (N = 58) was drawn from an existing database created for the revision of the Scales. Information was collated using clinical files, biographical data as well as the results of an assessment on the Revised Extended Griffiths Scales. The major findings of the study are summarised below. The general performance of the hearing impaired sample on the Revised Extended Griffiths Scales was average. The performance of the children on the six subscales ranged from below average to average, with major fall-outs occurring on the Hearing and Speech and Practical Reasoning Subscales. The normal sample performed significantly better than the hearing impaired sample on all of the subscales of the measure. However, significant differences were found on four of the six subscales, namely, the Locomotor, Personal-Social, Hearing and Speech and Practical Reasoning Subscales. Generally, the results of the current study suggest that a specific developmental profile is obtained for hearing impaired children. In addition, this study has highlighted the success with which the Revised Extended Griffiths Scales can be utilised on a hearing impaired population.
- Full Text:
- Date Issued: 2004
The regulation of domain name disputes in South Africa
- Authors: Nyachowe, Pasno N
- Date: 2003
- Subjects: Trademarks -- Law and legislation -- South Africa , Internet domain names -- Law and legislation , Internet domain names -- Law and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11050 , http://hdl.handle.net/10948/351 , Trademarks -- Law and legislation -- South Africa , Internet domain names -- Law and legislation , Internet domain names -- Law and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Description: This treatise provides an overview of the procedures for the registration, regulation and protection of Internet domain names. An analysis of legal rules applicable to domain names and problems related to the protection of domain names in South Africa, United State, United Kingdom and internationally is undertaken. The problems includes cybersquatting, misuse of personal names, reverse domain hijacking, misuse of meta tags and keywords. The treatise established possible solutions applicable to South Africa by investigating how other countries have dealt with such problems, and further investigated the extent to which South African legislation is suited to deal with such problems. An investigation of the regulation in terms of the Electronic Communications and Transactions Act 25 of 2002 is briefly attempted, and proposals for the future on the South African domain name system suggested.
- Full Text:
- Date Issued: 2003
- Authors: Nyachowe, Pasno N
- Date: 2003
- Subjects: Trademarks -- Law and legislation -- South Africa , Internet domain names -- Law and legislation , Internet domain names -- Law and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11050 , http://hdl.handle.net/10948/351 , Trademarks -- Law and legislation -- South Africa , Internet domain names -- Law and legislation , Internet domain names -- Law and legislation -- South Africa , Dispute resolution (Law) -- South Africa
- Description: This treatise provides an overview of the procedures for the registration, regulation and protection of Internet domain names. An analysis of legal rules applicable to domain names and problems related to the protection of domain names in South Africa, United State, United Kingdom and internationally is undertaken. The problems includes cybersquatting, misuse of personal names, reverse domain hijacking, misuse of meta tags and keywords. The treatise established possible solutions applicable to South Africa by investigating how other countries have dealt with such problems, and further investigated the extent to which South African legislation is suited to deal with such problems. An investigation of the regulation in terms of the Electronic Communications and Transactions Act 25 of 2002 is briefly attempted, and proposals for the future on the South African domain name system suggested.
- Full Text:
- Date Issued: 2003
The relationship between trait anxiety and anxiety sensitivity
- Authors: Farrington, Robin Mark
- Date: 2004
- Subjects: Anxiety sensitivity -- South Africa , Anxiety -- South Africa -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11021 , http://hdl.handle.net/10948/352 , Anxiety sensitivity -- South Africa , Anxiety -- South Africa -- Testing
- Description: Anxiety Sensitivity (AS) is a useful psychological construct in understanding the development of general and clinical anxiety. An increased amount of research has recently been conducted in this area. Since the development of the 16-item Anxiety Sensitivity Index (ASI), there has been deliberation in the literature about the relationship of the AS construct and the ASI, to the personality construct of trait anxiety. Central to this discus sion is the notion that AS is nothing more than trait anxiety. This position brings into question the conceptual and empirical validity of AS. This study aimed to explore and describe the relationship between trait anxiety and anxiety sensitivity, through the use of an exploratory-descriptive correlational design. Levels of trait anxiety were determined through the use of subscales on the Sixteen Personality Factor Questionnaire (16PF) and anxiety sensitivity through the use of the ASI. Using a convenience sampling technique, 84 student volunteers completed the 16PF and ASI. Descriptive statistics and inferential statistics were employed for data analysis. The results indicate that the sample group had the capacity to express emotional energy along integrated channels and was thus well suited for exploring the relationship between the construct of trait anxiety and anxiety sensitivity. The relationship between trait anxiety and AS in the sample group was explored through the use of two statistical procedures. Firstly, the coefficient of determination (r²) was calculated and revealed that 24% of the variance among the ASI scores were attributable to variations in Factor QII scores of the 16PF and viceversa. Secondly, a multiple regression analysis technique revealed that 28% of the variance in the ASI score could be explained by the combination of factors Q4 (free- floating anxiety), O (guilt proneness), C (ego strength), L (suspiciousness), Q3 (ability to bind anxiety) of the 16PF. These key findings are in line with other research in that the constructs of trait anxiety and anxiety sensitivity showed a level of variance. As such, it was concluded that although the constructs may be related, they are not synonymous.
- Full Text:
- Date Issued: 2004
- Authors: Farrington, Robin Mark
- Date: 2004
- Subjects: Anxiety sensitivity -- South Africa , Anxiety -- South Africa -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11021 , http://hdl.handle.net/10948/352 , Anxiety sensitivity -- South Africa , Anxiety -- South Africa -- Testing
- Description: Anxiety Sensitivity (AS) is a useful psychological construct in understanding the development of general and clinical anxiety. An increased amount of research has recently been conducted in this area. Since the development of the 16-item Anxiety Sensitivity Index (ASI), there has been deliberation in the literature about the relationship of the AS construct and the ASI, to the personality construct of trait anxiety. Central to this discus sion is the notion that AS is nothing more than trait anxiety. This position brings into question the conceptual and empirical validity of AS. This study aimed to explore and describe the relationship between trait anxiety and anxiety sensitivity, through the use of an exploratory-descriptive correlational design. Levels of trait anxiety were determined through the use of subscales on the Sixteen Personality Factor Questionnaire (16PF) and anxiety sensitivity through the use of the ASI. Using a convenience sampling technique, 84 student volunteers completed the 16PF and ASI. Descriptive statistics and inferential statistics were employed for data analysis. The results indicate that the sample group had the capacity to express emotional energy along integrated channels and was thus well suited for exploring the relationship between the construct of trait anxiety and anxiety sensitivity. The relationship between trait anxiety and AS in the sample group was explored through the use of two statistical procedures. Firstly, the coefficient of determination (r²) was calculated and revealed that 24% of the variance among the ASI scores were attributable to variations in Factor QII scores of the 16PF and viceversa. Secondly, a multiple regression analysis technique revealed that 28% of the variance in the ASI score could be explained by the combination of factors Q4 (free- floating anxiety), O (guilt proneness), C (ego strength), L (suspiciousness), Q3 (ability to bind anxiety) of the 16PF. These key findings are in line with other research in that the constructs of trait anxiety and anxiety sensitivity showed a level of variance. As such, it was concluded that although the constructs may be related, they are not synonymous.
- Full Text:
- Date Issued: 2004