A five year comparative analysis of annual baseline neurocognitive test scores for South African high school athletes
- Reichling, Marcelle Antoinette
- Authors: Reichling, Marcelle Antoinette
- Date: 2020
- Subjects: High school athletes -- Intelligence testing , Sports -- Psychological aspects , Neuropsychological tests , Brain -- Wounds and injuries -- Psychology , Sports injuries -- Psychological aspects , Brain -- Concussion , Head -- Wounds and injuries
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145863 , vital:38473
- Description: The primary objective of this study was to assess the pattern of change in neurocognitive performance for adolescent athletes on baseline measures of the Immediate Post Concussion Assessment and Cognitive Testing (ImPACT) test, over five consecutive years, with a view to providing an indication of the optimal interval for repeat baseline testing of high school athletes. Participants were non-clinical, predominantly South African high school athletes in the overall age range 13 to 18 years (N = 108), divided into five groups (Grades 8,9, 10, 11 and 12), and tested at five test intervals. Repeated-measures ANOVA analyses examined differences in score performance across the test intervals for each of the five composite scores of the ImPACT test (Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time, Impulse Control). For the Verbal Memory, Visual Memory, Visual Motor Speed and Reaction Time composites there were significant neurocognitive score changes between several test intervals. Taking these results into account, in conjunction with substantial variability in performance, it is concluded that there is a need for annual baseline testing throughout the high school years. The secondary objective was to generate normative tables (Means and Standard Deviations) on the ImPACT test for the five participant groups at each of the five test intervals, including data for: the five composite scores (Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time, Impulse Control); for the twelve subtest scores test that go to make up the composite scores; and for four additional memory subcomponent scores (Word Memory immediate recall, Word Memory delayed recall, Design Memory immediate recall, Design Memory delayed recall). The results provide a clinical and heuristic normative platform for future use with brain injured individuals, which can be used to facilitate clinical interpretations of postconcussion assessments.
- Full Text:
- Date Issued: 2020
- Authors: Reichling, Marcelle Antoinette
- Date: 2020
- Subjects: High school athletes -- Intelligence testing , Sports -- Psychological aspects , Neuropsychological tests , Brain -- Wounds and injuries -- Psychology , Sports injuries -- Psychological aspects , Brain -- Concussion , Head -- Wounds and injuries
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145863 , vital:38473
- Description: The primary objective of this study was to assess the pattern of change in neurocognitive performance for adolescent athletes on baseline measures of the Immediate Post Concussion Assessment and Cognitive Testing (ImPACT) test, over five consecutive years, with a view to providing an indication of the optimal interval for repeat baseline testing of high school athletes. Participants were non-clinical, predominantly South African high school athletes in the overall age range 13 to 18 years (N = 108), divided into five groups (Grades 8,9, 10, 11 and 12), and tested at five test intervals. Repeated-measures ANOVA analyses examined differences in score performance across the test intervals for each of the five composite scores of the ImPACT test (Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time, Impulse Control). For the Verbal Memory, Visual Memory, Visual Motor Speed and Reaction Time composites there were significant neurocognitive score changes between several test intervals. Taking these results into account, in conjunction with substantial variability in performance, it is concluded that there is a need for annual baseline testing throughout the high school years. The secondary objective was to generate normative tables (Means and Standard Deviations) on the ImPACT test for the five participant groups at each of the five test intervals, including data for: the five composite scores (Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time, Impulse Control); for the twelve subtest scores test that go to make up the composite scores; and for four additional memory subcomponent scores (Word Memory immediate recall, Word Memory delayed recall, Design Memory immediate recall, Design Memory delayed recall). The results provide a clinical and heuristic normative platform for future use with brain injured individuals, which can be used to facilitate clinical interpretations of postconcussion assessments.
- Full Text:
- Date Issued: 2020
A financial planning model for retirement, taking into account the impact of pre-retirement funding income, age and taxation
- Authors: Barnes, Andrew
- Date: 2006
- Subjects: Retirement -- South Africa Retirement income -- Planning -- South Africa Pensions -- Planning -- South Africa Finance, Personal Investments Income tax -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:895 , http://hdl.handle.net/10962/d1004532
- Description: Individuals are often not aware of the required level of contributions needed to fund a retirement savings plan. This problem is compounded by the fact that the assistance provided to these individuals by way of commercially-available retirement planning models does not take into account the effect of income tax on the level of required retirement savings contributions and recent changes in the tax legislation to the income tax payable by individuals has had a significant effect on these required levels. As a preamble to the research process, an exploratory questionnaire was administrated to a sample of individuals, which was designed to measure the level of awareness of these individuals of the contributions to a retirement savings plan needed to fund their postretirement financial needs, and of the impact of age, the level of income and income tax on their contributions. Responses to the questionnaire indicated a low level of awareness of retirement planning amongst these individuals. A retirement planning model was then designed to test the effect of earnings, age and changes in tax legislation on the level of an individual's required monthly contributions to a retirement savings plan. Independent variables of age and income were processed using the model. These same variables were then processed using the Old Mutual and Liberty Life retirement planning models and a comparison was made between the model developed in the research and these commercially developed models, to assess their usefulness and limitations. Based on the above comparison, it appeared that the Old Mutual and Liberty Life retirement models both included the effects of the individual marginal tax rates in their calculations. However, they appeared to be using marginal tax rates which were higher than those reflected in the 2006 individual income tax tables. In addition these models did not include the effect of income tax exemptions and deductions and they therefore provided more conservative estimates than the retirement planning model designed in the research. Recent tax adjustments have had the effect of greatly increasing the after-tax income of individuals and therefore it is important to include the effects of changes in tax legislation in determining the monthly contributions to a retirement savings plan.
- Full Text:
- Date Issued: 2006
- Authors: Barnes, Andrew
- Date: 2006
- Subjects: Retirement -- South Africa Retirement income -- Planning -- South Africa Pensions -- Planning -- South Africa Finance, Personal Investments Income tax -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:895 , http://hdl.handle.net/10962/d1004532
- Description: Individuals are often not aware of the required level of contributions needed to fund a retirement savings plan. This problem is compounded by the fact that the assistance provided to these individuals by way of commercially-available retirement planning models does not take into account the effect of income tax on the level of required retirement savings contributions and recent changes in the tax legislation to the income tax payable by individuals has had a significant effect on these required levels. As a preamble to the research process, an exploratory questionnaire was administrated to a sample of individuals, which was designed to measure the level of awareness of these individuals of the contributions to a retirement savings plan needed to fund their postretirement financial needs, and of the impact of age, the level of income and income tax on their contributions. Responses to the questionnaire indicated a low level of awareness of retirement planning amongst these individuals. A retirement planning model was then designed to test the effect of earnings, age and changes in tax legislation on the level of an individual's required monthly contributions to a retirement savings plan. Independent variables of age and income were processed using the model. These same variables were then processed using the Old Mutual and Liberty Life retirement planning models and a comparison was made between the model developed in the research and these commercially developed models, to assess their usefulness and limitations. Based on the above comparison, it appeared that the Old Mutual and Liberty Life retirement models both included the effects of the individual marginal tax rates in their calculations. However, they appeared to be using marginal tax rates which were higher than those reflected in the 2006 individual income tax tables. In addition these models did not include the effect of income tax exemptions and deductions and they therefore provided more conservative estimates than the retirement planning model designed in the research. Recent tax adjustments have had the effect of greatly increasing the after-tax income of individuals and therefore it is important to include the effects of changes in tax legislation in determining the monthly contributions to a retirement savings plan.
- Full Text:
- Date Issued: 2006
A field investigation of physical workloads imposed on harvesters in South African forestry
- Authors: Christie, Candice Jo-Anne
- Date: 2006
- Subjects: Forests and forestry -- South Africa Employees -- Workload Forest products industry -- South Africa Work -- Physiological aspects Heart rate monitoring Foresters -- South Africa -- Workload Oxygen -- Physiological transport
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5122 , http://hdl.handle.net/10962/d1005200
- Description: The focus of this field investigation was an analysis of the work demands being placed on South African forestry workers, in particular Chainsaw Operators and Stackers. Working postures, physiological and perceptual responses were assessed on a sample of 58 workers (29 Chainsaw Operators and 29 Stackers) during a ‘normal’ working shift. Body mass was measured before and after work in order to determine dehydration levels. Polar heart rate monitors were fitted to six workers each day over a period of two weeks in order to record ‘working’ heart rates. Fluid and food intake was monitored and recorded during this initial data collection phase. The Rating of Perceived Exertion and Body Discomfort Scales were explained in Zulu, their native language, and workers were asked to rate their perceptions of effort at regular intervals during work, while areas and intensity of body discomfort was obtained on completion of work. After completing a work shift, a 30 minute ‘recovery’ period was given, thereafter a portable ergospirometer, the k4b², was attached to the worker who then participated in a progressive, submaximal step test for the purpose of establishing individual, and group, heart rate-oxygen uptake (HR/VO[subscript 2]) regressions for predicting oxygen uptake from ‘working’ heart rate responses. These procedures were repeated four weeks later following the introduction of a fluid and nutritional supplement during work which was delivered to the workers while they were executing their tasks. The results revealed awkward working postures with a predominance of trunk flexion during all the harvesting tasks; these postures, adopted for long periods during work, are very likely to lead to the development of musculoskeletal injuries. The mean working heart rates were 123.3 bt.min[superscript (-1)] and 117.6 bt.min[superscript (-1)] during chainsaw operations and stacking respectively. During the step test, the mean heart rate and oxygen uptake responses were 127.9 bt.min[superscript (-1)] and 22.9 mlO[subscript 2].kg[superscript (-1)].min[superscript (-1)] (Chainsaw Operators) and 116.9 bt.min[superscript (-1)] and 24.0 mlO[subscript 2].kg[superscript (-1)].min[superscript (-1)] (Stackers), revealing no significant difference between the ‘working’ heart rates and the heart rates recorded during the step test. Physiological responses were analyzed over the full work shift which was divided into four quarters. Heart rate and oxygen uptake were significantly higher during the last half of the Chainsaw Operators’ work shift compared to the first half. Heart rate increased from 120.7 bt.min[superscript (-1)] during the first quarter to 127.4 bt.min[superscript (-1)] during the last quarter of chainsaw operations. Likewise, oxygen uptake increased from 19.9 mlO[subscript 2].kg[superscript (-1)].min[superscript (-1)] to 22.9 mlO[subscript 2].kg[superscript (-1)].min[superscript (-1)] from the first to the last quarter of work. During stacking the heart rate (mean of 117.6 bt.min[superscript (-1)]) and oxygen uptake (mean of 24.6 ml.kg[superscript (-1)].min[superscript (-1)]) responses remained stable over the duration of the working shift. Workers lost, on average, 2.8% body mass during work while felling and cross-cutting and 3.6% during stacking. This reduced significantly to a loss of 0.4% body mass when re-tested following the introduction of water and food during the work period. Likewise, the energy deficit was significantly improved due to the introduction of a nutritional supplement. Pre-intervention the deficit was 8861.8 kJ (Chainsaw Operators) and 8804.2 kJ (Stackers) while in the post-intervention phase this deficit was reduced by approximately 50% for both groups of workers.
- Full Text:
- Date Issued: 2006
- Authors: Christie, Candice Jo-Anne
- Date: 2006
- Subjects: Forests and forestry -- South Africa Employees -- Workload Forest products industry -- South Africa Work -- Physiological aspects Heart rate monitoring Foresters -- South Africa -- Workload Oxygen -- Physiological transport
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5122 , http://hdl.handle.net/10962/d1005200
- Description: The focus of this field investigation was an analysis of the work demands being placed on South African forestry workers, in particular Chainsaw Operators and Stackers. Working postures, physiological and perceptual responses were assessed on a sample of 58 workers (29 Chainsaw Operators and 29 Stackers) during a ‘normal’ working shift. Body mass was measured before and after work in order to determine dehydration levels. Polar heart rate monitors were fitted to six workers each day over a period of two weeks in order to record ‘working’ heart rates. Fluid and food intake was monitored and recorded during this initial data collection phase. The Rating of Perceived Exertion and Body Discomfort Scales were explained in Zulu, their native language, and workers were asked to rate their perceptions of effort at regular intervals during work, while areas and intensity of body discomfort was obtained on completion of work. After completing a work shift, a 30 minute ‘recovery’ period was given, thereafter a portable ergospirometer, the k4b², was attached to the worker who then participated in a progressive, submaximal step test for the purpose of establishing individual, and group, heart rate-oxygen uptake (HR/VO[subscript 2]) regressions for predicting oxygen uptake from ‘working’ heart rate responses. These procedures were repeated four weeks later following the introduction of a fluid and nutritional supplement during work which was delivered to the workers while they were executing their tasks. The results revealed awkward working postures with a predominance of trunk flexion during all the harvesting tasks; these postures, adopted for long periods during work, are very likely to lead to the development of musculoskeletal injuries. The mean working heart rates were 123.3 bt.min[superscript (-1)] and 117.6 bt.min[superscript (-1)] during chainsaw operations and stacking respectively. During the step test, the mean heart rate and oxygen uptake responses were 127.9 bt.min[superscript (-1)] and 22.9 mlO[subscript 2].kg[superscript (-1)].min[superscript (-1)] (Chainsaw Operators) and 116.9 bt.min[superscript (-1)] and 24.0 mlO[subscript 2].kg[superscript (-1)].min[superscript (-1)] (Stackers), revealing no significant difference between the ‘working’ heart rates and the heart rates recorded during the step test. Physiological responses were analyzed over the full work shift which was divided into four quarters. Heart rate and oxygen uptake were significantly higher during the last half of the Chainsaw Operators’ work shift compared to the first half. Heart rate increased from 120.7 bt.min[superscript (-1)] during the first quarter to 127.4 bt.min[superscript (-1)] during the last quarter of chainsaw operations. Likewise, oxygen uptake increased from 19.9 mlO[subscript 2].kg[superscript (-1)].min[superscript (-1)] to 22.9 mlO[subscript 2].kg[superscript (-1)].min[superscript (-1)] from the first to the last quarter of work. During stacking the heart rate (mean of 117.6 bt.min[superscript (-1)]) and oxygen uptake (mean of 24.6 ml.kg[superscript (-1)].min[superscript (-1)]) responses remained stable over the duration of the working shift. Workers lost, on average, 2.8% body mass during work while felling and cross-cutting and 3.6% during stacking. This reduced significantly to a loss of 0.4% body mass when re-tested following the introduction of water and food during the work period. Likewise, the energy deficit was significantly improved due to the introduction of a nutritional supplement. Pre-intervention the deficit was 8861.8 kJ (Chainsaw Operators) and 8804.2 kJ (Stackers) while in the post-intervention phase this deficit was reduced by approximately 50% for both groups of workers.
- Full Text:
- Date Issued: 2006
A field investigation into the impact of task demands on worker responses in the South African forestry silviculture sector
- Authors: Parker, Rhiannon Jennifer
- Date: 2014
- Subjects: Forests and forestry -- South Africa -- KwaZulu-Natal , Blue collar workers -- South Africa -- KwaZulu-Natal , Manual work -- South Africa -- KwaZulu-Natal , Work -- Physiological aspects , Human mechanics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5157 , http://hdl.handle.net/10962/d1015645
- Description: Background: In South Africa, limited research has focused on the task demands and workers responses associated with forestry silviculture work, particularly pitting and planting. The methods currently in use are manual, but despite our lack of understanding of the existing demands, advances in forestry engineering have resulted in an introduction of semi-mechanised versions of these tasks. This project aimed to compare the task demands of silviculture tasks using the current manual techniques and the more modern, semi-mechanised techniques. Methods: A holistic investigation focused on the worker characteristics of a sample of black male pitters and black female planters from the Kwa-Zulu Natal forestry industry, as well as biomechanical (spinal kinematics and L5/S1 forces), physiological (heart rate, oxygen consumption and energy expenditure) and psychophysical (ratings of perceived exertion and body discomfort) responses associated with manual and semi-mechanised pitting and planting. Results: The pitting task saw significant improvements in the spinal kinematic measures as a result of the increased mechanisation, with eight of the 16 recorded variables decreasing to a lower level of risk classification. Physiologically, the manual task was associated with a mean heart rate of 157 bt.min⁻¹ and absolute energy expenditure of 11.27 kcal.min⁻¹, which were not found to be significantly different to the values of 143 bt.min⁻¹ and 9.8 kcal.min⁻¹ recorded during the semi-mechanised technique. Psychophysical responses indicated that the workers perceived manual pitting to be more physically demanding than the semi-mechanised method. The manual and semi-mechanised planting tasks were, in general, found to be acceptable from a spinal kinematics perspective, with the majority of variables classified as low risk. However, the maximum sagittal angle was reduced by more than 20 degrees as a result of the new equipment. The physiological and psychophysical demands associated with manual planting were found to be within acceptable limits. Conclusion: In terms of pitting, it can tentatively be concluded that the semi-mechanised technique is better than the manual one, based on the biomechanical and psychophysical findings, however physiological demands require further investigation. When considering the planting techniques, the semi-mechanised method showed a slight improvement from the biomechanical perspective, but further physiological and psychophysical investigations are needed.
- Full Text:
- Date Issued: 2014
- Authors: Parker, Rhiannon Jennifer
- Date: 2014
- Subjects: Forests and forestry -- South Africa -- KwaZulu-Natal , Blue collar workers -- South Africa -- KwaZulu-Natal , Manual work -- South Africa -- KwaZulu-Natal , Work -- Physiological aspects , Human mechanics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5157 , http://hdl.handle.net/10962/d1015645
- Description: Background: In South Africa, limited research has focused on the task demands and workers responses associated with forestry silviculture work, particularly pitting and planting. The methods currently in use are manual, but despite our lack of understanding of the existing demands, advances in forestry engineering have resulted in an introduction of semi-mechanised versions of these tasks. This project aimed to compare the task demands of silviculture tasks using the current manual techniques and the more modern, semi-mechanised techniques. Methods: A holistic investigation focused on the worker characteristics of a sample of black male pitters and black female planters from the Kwa-Zulu Natal forestry industry, as well as biomechanical (spinal kinematics and L5/S1 forces), physiological (heart rate, oxygen consumption and energy expenditure) and psychophysical (ratings of perceived exertion and body discomfort) responses associated with manual and semi-mechanised pitting and planting. Results: The pitting task saw significant improvements in the spinal kinematic measures as a result of the increased mechanisation, with eight of the 16 recorded variables decreasing to a lower level of risk classification. Physiologically, the manual task was associated with a mean heart rate of 157 bt.min⁻¹ and absolute energy expenditure of 11.27 kcal.min⁻¹, which were not found to be significantly different to the values of 143 bt.min⁻¹ and 9.8 kcal.min⁻¹ recorded during the semi-mechanised technique. Psychophysical responses indicated that the workers perceived manual pitting to be more physically demanding than the semi-mechanised method. The manual and semi-mechanised planting tasks were, in general, found to be acceptable from a spinal kinematics perspective, with the majority of variables classified as low risk. However, the maximum sagittal angle was reduced by more than 20 degrees as a result of the new equipment. The physiological and psychophysical demands associated with manual planting were found to be within acceptable limits. Conclusion: In terms of pitting, it can tentatively be concluded that the semi-mechanised technique is better than the manual one, based on the biomechanical and psychophysical findings, however physiological demands require further investigation. When considering the planting techniques, the semi-mechanised method showed a slight improvement from the biomechanical perspective, but further physiological and psychophysical investigations are needed.
- Full Text:
- Date Issued: 2014
A feasibility study into total electron content prediction using neural networks
- Authors: Habarulema, John Bosco
- Date: 2008
- Subjects: Electrons , Neural networks (Computer science) , Global Positioning System , Ionosphere , Ionospheric electron density
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5466 , http://hdl.handle.net/10962/d1005251 , Electrons , Neural networks (Computer science) , Global Positioning System , Ionosphere , Ionospheric electron density
- Description: Global Positioning System (GPS) networks provide an opportunity to study the dynamics and continuous changes in the ionosphere by supplementing ionospheric measurements which are usually obtained by various techniques such as ionosondes, incoherent scatter radars and satellites. Total electron content (TEC) is one of the physical quantities that can be derived from GPS data, and provides an indication of ionospheric variability. This thesis presents a feasibility study for the development of a Neural Network (NN) based model for the prediction of South African GPS derived TEC. The South African GPS receiver network is operated and maintained by the Chief Directorate Surveys and Mapping (CDSM) in Cape Town, South Africa. Three South African locations were identified and used in the development of an input space and NN architecture for the model. The input space includes the day number (seasonal variation), hour (diurnal variation), sunspot number (measure of the solar activity), and magnetic index(measure of the magnetic activity). An attempt to study the effects of solar wind on TEC variability was carried out using the Advanced Composition Explorer (ACE) data and it is recommended that more study be done using low altitude satellite data. An analysis was done by comparing predicted NN TEC with TEC values from the IRI2001 version of the International Reference Ionosphere (IRI), validating GPS TEC with ionosonde TEC (ITEC) and assessing the performance of the NN model during equinoxes and solstices. Results show that NNs predict GPS TEC more accurately than the IRI at South African GPS locations, but that more good quality GPS data is required before a truly representative empirical GPS TEC model can be released.
- Full Text:
- Date Issued: 2008
- Authors: Habarulema, John Bosco
- Date: 2008
- Subjects: Electrons , Neural networks (Computer science) , Global Positioning System , Ionosphere , Ionospheric electron density
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5466 , http://hdl.handle.net/10962/d1005251 , Electrons , Neural networks (Computer science) , Global Positioning System , Ionosphere , Ionospheric electron density
- Description: Global Positioning System (GPS) networks provide an opportunity to study the dynamics and continuous changes in the ionosphere by supplementing ionospheric measurements which are usually obtained by various techniques such as ionosondes, incoherent scatter radars and satellites. Total electron content (TEC) is one of the physical quantities that can be derived from GPS data, and provides an indication of ionospheric variability. This thesis presents a feasibility study for the development of a Neural Network (NN) based model for the prediction of South African GPS derived TEC. The South African GPS receiver network is operated and maintained by the Chief Directorate Surveys and Mapping (CDSM) in Cape Town, South Africa. Three South African locations were identified and used in the development of an input space and NN architecture for the model. The input space includes the day number (seasonal variation), hour (diurnal variation), sunspot number (measure of the solar activity), and magnetic index(measure of the magnetic activity). An attempt to study the effects of solar wind on TEC variability was carried out using the Advanced Composition Explorer (ACE) data and it is recommended that more study be done using low altitude satellite data. An analysis was done by comparing predicted NN TEC with TEC values from the IRI2001 version of the International Reference Ionosphere (IRI), validating GPS TEC with ionosonde TEC (ITEC) and assessing the performance of the NN model during equinoxes and solstices. Results show that NNs predict GPS TEC more accurately than the IRI at South African GPS locations, but that more good quality GPS data is required before a truly representative empirical GPS TEC model can be released.
- Full Text:
- Date Issued: 2008
A feasibility study into the possibility of ionospheric propagation of low VHF (30-35 MHZ) signals between South Africa and Central Africa
- Authors: Coetzee, Petrus Johannes
- Date: 2009
- Subjects: Communications, Military -- South Africa , Communications, Military -- Africa, Central , Digital communications -- South Africa , Digital communications -- Africa, Central , Signals and signaling -- South Africa , Signals and signaling -- Africa, Central , Artificial satellites in telecommunication -- South Africa , Artificial satellites in telecommunication -- Africa, Central , Shortwave radio
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5465 , http://hdl.handle.net/10962/d1005250 , Communications, Military -- South Africa , Communications, Military -- Africa, Central , Digital communications -- South Africa , Digital communications -- Africa, Central , Signals and signaling -- South Africa , Signals and signaling -- Africa, Central , Artificial satellites in telecommunication -- South Africa , Artificial satellites in telecommunication -- Africa, Central , Shortwave radio
- Description: The role of the South African National Defence Force (SANDF) has changed considerably in the last decade. The emphasis has moved from protecting the country's borders to peacekeeping duties in Central Africa and even further North. Communications between the peacekeeping missions and the military bases back in South Africa is vital to ensure the success of these missions. Currently use is made of satellite as well as High Frequency (HF) communications. There are drawbacks associated with these technologies (high cost and low data rates/interference respectively). Successful long distance ionospheric propagation in the low Very High Frequency (VHF) range will complement the existing infrastructure and enhance the success rate of these missions. This thesis presents a feasibility study to determine under what ionospheric conditions such low VHF communications will be possible. The International Reference Ionosphere (IRI) was used to generate ionospheric data for the reflection point(s) of the signal. The peak height of the ionospheric F2 layer (hmF2) was used to calculate the required antenna elevation angle. Once the elevation angle is known it is possible to calculate the required F2 layer critical frequency (foF2). The required foF2 value was calculated by assuming a Maximum Useable Frequency (MUF) of 20% higher than the planned operational frequency. It was determined that single hop propagation is possible during the daytime if the smoothed sunspot number (SSN) exceeds 15. The most challenging requirement for successful single hop propagation is the need of an antenna height of 23 m. For rapid deployment and semi-mobile operations within a jungle environment it may prove to be a formidable obstacle.
- Full Text:
- Date Issued: 2009
- Authors: Coetzee, Petrus Johannes
- Date: 2009
- Subjects: Communications, Military -- South Africa , Communications, Military -- Africa, Central , Digital communications -- South Africa , Digital communications -- Africa, Central , Signals and signaling -- South Africa , Signals and signaling -- Africa, Central , Artificial satellites in telecommunication -- South Africa , Artificial satellites in telecommunication -- Africa, Central , Shortwave radio
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5465 , http://hdl.handle.net/10962/d1005250 , Communications, Military -- South Africa , Communications, Military -- Africa, Central , Digital communications -- South Africa , Digital communications -- Africa, Central , Signals and signaling -- South Africa , Signals and signaling -- Africa, Central , Artificial satellites in telecommunication -- South Africa , Artificial satellites in telecommunication -- Africa, Central , Shortwave radio
- Description: The role of the South African National Defence Force (SANDF) has changed considerably in the last decade. The emphasis has moved from protecting the country's borders to peacekeeping duties in Central Africa and even further North. Communications between the peacekeeping missions and the military bases back in South Africa is vital to ensure the success of these missions. Currently use is made of satellite as well as High Frequency (HF) communications. There are drawbacks associated with these technologies (high cost and low data rates/interference respectively). Successful long distance ionospheric propagation in the low Very High Frequency (VHF) range will complement the existing infrastructure and enhance the success rate of these missions. This thesis presents a feasibility study to determine under what ionospheric conditions such low VHF communications will be possible. The International Reference Ionosphere (IRI) was used to generate ionospheric data for the reflection point(s) of the signal. The peak height of the ionospheric F2 layer (hmF2) was used to calculate the required antenna elevation angle. Once the elevation angle is known it is possible to calculate the required F2 layer critical frequency (foF2). The required foF2 value was calculated by assuming a Maximum Useable Frequency (MUF) of 20% higher than the planned operational frequency. It was determined that single hop propagation is possible during the daytime if the smoothed sunspot number (SSN) exceeds 15. The most challenging requirement for successful single hop propagation is the need of an antenna height of 23 m. For rapid deployment and semi-mobile operations within a jungle environment it may prove to be a formidable obstacle.
- Full Text:
- Date Issued: 2009
A dynamics based analysis of allosteric modulation in heat shock proteins
- Authors: Penkler, David Lawrence
- Date: 2019
- Subjects: Heat shock proteins , Molecular chaperones , Allosteric regulation , Homeostasis , Protein kinases , Transcription factors , Adenosine triphosphatase , Cancer -- Chemotherapy , Molecular dynamics , High throughput screening (Drug development)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115948 , vital:34273
- Description: The 70 kDa and 90 kDa heat shock proteins (Hsp70 and Hsp90) are molecular chaperones that play central roles in maintaining cellular homeostasis in all organisms of life with the exception of archaea. In addition to their general chaperone function in protein quality control, Hsp70 and Hsp90 cooperate in the regulation and activity of some 200 known natively folded protein clients which include protein kinases, transcription factors and receptors, many of which are implicated as key regulators of essential signal transduction pathways. Both chaperones are considered to be large multi-domain proteins that rely on ATPase activity and co-chaperone interactions to regulate their conformational cycles for peptide binding and release. The unique positioning of Hsp90 at the crossroads of several fundamental cellular pathways coupled with its known association with diverse oncogenic peptide clients has brought the molecular chaperone under increasing interest as a potential anti-cancer target that is crucially implicated with all eight hallmarks of the disease. Current orthosteric drug discovery efforts aimed at the inhibition of the ATPase domain of Hsp90 have been limited due to high levels of associated toxicity. In an effort to circumnavigate this, the combined focus of research efforts is shifting toward alternative approaches such as interference with co-chaperone binding and the allosteric inhibition/activation of the molecular chaperone. The overriding aim of this thesis was to demonstrate how the computational technique of Perturbation response scanning (PRS) coupled with all-atom molecular dynamics simulations (MD) and dynamic residue interaction network (DRN) analysis can be used as a viable strategy to efficiently scan and accurately identify allosteric control element capable of modulating the functional dynamics of a protein. In pursuit of this goal, this thesis also contributes to the current understanding of the nucleotide dependent allosteric mechanisms at play in cellular functionality of both Hsp70 and Hsp90. All-atom MD simulations of E. coli DnaK provided evidence of nucleotide driven modulation of conformational dynamics in both the catalytically active and inactive states. PRS analysis employed on these trajectories demonstrated sensitivity toward bound nucleotide and peptide substrate, and provided evidence of a putative allosterically active intermediate state between the ATPase active and inactive conformational states. Simultaneous binding of ATP and peptide substrate was found to allosterically prime the chaperone for interstate conversion regardless of the transition direction. Detailed analysis of these allosterically primed states revealed select residue sites capable of selecting a coordinate shift towards the opposite conformational state. In an effort to validate these results, the predicted allosteric hot spot sites were cross-validated with known experimental works and found to overlap with functional sites implicated in allosteric signal propagation and ATPase activation in Hsp70. This study presented for the first time, the application of PRS as a suitable diagnostic tool for the elucidation and quantification of the allosteric potential of select residues to effect functionally relevant global conformational rearrangements. The PRS methodology described in this study was packaged within the Python programming environment in the MD-TASK software suite for command-line ease of use and made freely available. Homology modelling techniques were used to address the lack of experimental structural data for the human cytosolic isoform of Hsp90 and for the first time provided accurate full-length structural models of human Hsp90α in fully-closed and partially-open conformations. Long-range all-atom MD simulations of these structures revealed nucleotide driven modulation of conformational dynamics in Hsp90. Subsequent DRN and PRS analysis of these MD trajectories allowed for the quantification and elucidation of nucleotide driven allosteric modulation in the molecular chaperone. A detailed PRS analysis revealed allosteric inter-domain coupling between the extreme terminals of the chaperone in response to external force perturbations at either domain. Furthermore PRS also identified several individual residue sites that are capable of selecting conformational rearrangements towards functionally relevant states which may be considered to be putative allosteric target sites for future drug discovery efforts Molecular docking techniques were employed to investigate the modulation of conformational dynamics of human Hsp90α in response to ligand binding interactions at two identified allosteric sites at the C-terminal. High throughput screening of a small library of natural compounds indigenous to South Africa revealed three hit compounds at these sites: Cephalostatin 17, 20(29)-Lupene-3β isoferulate and 3'-Bromorubrolide F. All-atom MD simulations on these protein-ligand complexes coupled with DRN analysis and several advanced trajectory based analysis techniques provided evidence of selective allosteric modulation of Hsp90α conformational dynamics in response to the identity and location of the bound ligands. Ligands bound at the four-helix bundle presented as putative allosteric inhibitors of Hsp90α, driving conformational dynamics in favour of dimer opening and possibly dimer separation. Meanwhile, ligand interactions at an adjacent sub-pocket located near the interface between the middle and C-terminal domains demonstrated allosteric activation of the chaperone, modulating conformational dynamics in favour of the fully-closed catalytically active conformational state. Taken together, the data presented in this thesis contributes to the understanding of allosteric modulation of conformational dynamics in Hsp70 and Hsp90, and provides a suitable platform for future biochemical and drug discovery studies. Furthermore, the molecular docking and computational identification of allosteric compounds with suitable binding affinity for allosteric sites at the CTD of human Hsp90α provide for the first time “proof-of-principle” for the use of PRS in conjunction with MD simulations and DRN analysis as a suitable method for the rapid identification of allosteric sites in proteins that can be probed by small molecule interaction. The data presented in this section could pave the way for future allosteric drug discovery studies for the treatment of Hsp90 associated pathologies.
- Full Text:
- Date Issued: 2019
- Authors: Penkler, David Lawrence
- Date: 2019
- Subjects: Heat shock proteins , Molecular chaperones , Allosteric regulation , Homeostasis , Protein kinases , Transcription factors , Adenosine triphosphatase , Cancer -- Chemotherapy , Molecular dynamics , High throughput screening (Drug development)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115948 , vital:34273
- Description: The 70 kDa and 90 kDa heat shock proteins (Hsp70 and Hsp90) are molecular chaperones that play central roles in maintaining cellular homeostasis in all organisms of life with the exception of archaea. In addition to their general chaperone function in protein quality control, Hsp70 and Hsp90 cooperate in the regulation and activity of some 200 known natively folded protein clients which include protein kinases, transcription factors and receptors, many of which are implicated as key regulators of essential signal transduction pathways. Both chaperones are considered to be large multi-domain proteins that rely on ATPase activity and co-chaperone interactions to regulate their conformational cycles for peptide binding and release. The unique positioning of Hsp90 at the crossroads of several fundamental cellular pathways coupled with its known association with diverse oncogenic peptide clients has brought the molecular chaperone under increasing interest as a potential anti-cancer target that is crucially implicated with all eight hallmarks of the disease. Current orthosteric drug discovery efforts aimed at the inhibition of the ATPase domain of Hsp90 have been limited due to high levels of associated toxicity. In an effort to circumnavigate this, the combined focus of research efforts is shifting toward alternative approaches such as interference with co-chaperone binding and the allosteric inhibition/activation of the molecular chaperone. The overriding aim of this thesis was to demonstrate how the computational technique of Perturbation response scanning (PRS) coupled with all-atom molecular dynamics simulations (MD) and dynamic residue interaction network (DRN) analysis can be used as a viable strategy to efficiently scan and accurately identify allosteric control element capable of modulating the functional dynamics of a protein. In pursuit of this goal, this thesis also contributes to the current understanding of the nucleotide dependent allosteric mechanisms at play in cellular functionality of both Hsp70 and Hsp90. All-atom MD simulations of E. coli DnaK provided evidence of nucleotide driven modulation of conformational dynamics in both the catalytically active and inactive states. PRS analysis employed on these trajectories demonstrated sensitivity toward bound nucleotide and peptide substrate, and provided evidence of a putative allosterically active intermediate state between the ATPase active and inactive conformational states. Simultaneous binding of ATP and peptide substrate was found to allosterically prime the chaperone for interstate conversion regardless of the transition direction. Detailed analysis of these allosterically primed states revealed select residue sites capable of selecting a coordinate shift towards the opposite conformational state. In an effort to validate these results, the predicted allosteric hot spot sites were cross-validated with known experimental works and found to overlap with functional sites implicated in allosteric signal propagation and ATPase activation in Hsp70. This study presented for the first time, the application of PRS as a suitable diagnostic tool for the elucidation and quantification of the allosteric potential of select residues to effect functionally relevant global conformational rearrangements. The PRS methodology described in this study was packaged within the Python programming environment in the MD-TASK software suite for command-line ease of use and made freely available. Homology modelling techniques were used to address the lack of experimental structural data for the human cytosolic isoform of Hsp90 and for the first time provided accurate full-length structural models of human Hsp90α in fully-closed and partially-open conformations. Long-range all-atom MD simulations of these structures revealed nucleotide driven modulation of conformational dynamics in Hsp90. Subsequent DRN and PRS analysis of these MD trajectories allowed for the quantification and elucidation of nucleotide driven allosteric modulation in the molecular chaperone. A detailed PRS analysis revealed allosteric inter-domain coupling between the extreme terminals of the chaperone in response to external force perturbations at either domain. Furthermore PRS also identified several individual residue sites that are capable of selecting conformational rearrangements towards functionally relevant states which may be considered to be putative allosteric target sites for future drug discovery efforts Molecular docking techniques were employed to investigate the modulation of conformational dynamics of human Hsp90α in response to ligand binding interactions at two identified allosteric sites at the C-terminal. High throughput screening of a small library of natural compounds indigenous to South Africa revealed three hit compounds at these sites: Cephalostatin 17, 20(29)-Lupene-3β isoferulate and 3'-Bromorubrolide F. All-atom MD simulations on these protein-ligand complexes coupled with DRN analysis and several advanced trajectory based analysis techniques provided evidence of selective allosteric modulation of Hsp90α conformational dynamics in response to the identity and location of the bound ligands. Ligands bound at the four-helix bundle presented as putative allosteric inhibitors of Hsp90α, driving conformational dynamics in favour of dimer opening and possibly dimer separation. Meanwhile, ligand interactions at an adjacent sub-pocket located near the interface between the middle and C-terminal domains demonstrated allosteric activation of the chaperone, modulating conformational dynamics in favour of the fully-closed catalytically active conformational state. Taken together, the data presented in this thesis contributes to the understanding of allosteric modulation of conformational dynamics in Hsp70 and Hsp90, and provides a suitable platform for future biochemical and drug discovery studies. Furthermore, the molecular docking and computational identification of allosteric compounds with suitable binding affinity for allosteric sites at the CTD of human Hsp90α provide for the first time “proof-of-principle” for the use of PRS in conjunction with MD simulations and DRN analysis as a suitable method for the rapid identification of allosteric sites in proteins that can be probed by small molecule interaction. The data presented in this section could pave the way for future allosteric drug discovery studies for the treatment of Hsp90 associated pathologies.
- Full Text:
- Date Issued: 2019
A drug utilisation review of lithium at a public sector psychiatric hospital
- Authors: Mapfumo, Charlotte
- Date: 2020-04
- Subjects: Lithium -- Therapeutic use , Psychiatric hospitals -- South Africa -- Grahamstown , Drug utilization , Psychiatric hospital care , Manic-depressive illness , Lithium -- Toxicology , Drug monitoring
- Language: English
- Type: text , Thesis , Masters , M.Pharm
- Identifier: http://hdl.handle.net/10962/150541 , vital:38983
- Description: Bipolar disorder (BD) is a common mental condition that affects about 60 million people globally. Lithium is among the drugs of choice used to treat BD and other affective disorders such as schizoaffective disorder (SD). Lithium is a mood stabiliser with antimanic, antidepressant and anti-suicidal properties. Lithium has complex mechanisms of action and a narrow therapeutic index (NTI). Therapeutic drug monitoring (TDM) is a vital component of lithium therapy due to its NTI. Lithium toxicity can occur at therapeutic levels and is characterised by symptoms such as blurred vision and convulsions. Lithium interacts with a number of drugs resulting in lithium toxicity or diminished effects of lithium. Symptoms of lithium toxicity range from abdominal pain, convulsions and death. Lithium use is associated with serious adverse effects on renal and thyroid function. Other adverse effects include tremor and weight gain. Monitoring of lithium serum levels, renal and thyroid function are therefore recommended for patients on lithium therapy. Monitoring of these parameters assists in the early detection of any problems associated with lithium use. The metabolic monitoring of lithium is vital due to the adverse effect profile of lithium and the current South African Standard Treatment Guidelines Hospital level: Adults, do not have any recommendations for the monitoring of metabolic parameters. The National Institute for Health and Care Excellence (NICE) may be used and adapted for the South African setting. Aim and Objectives: The general aim of the study was to conduct a drug utilisation review (DUR) on lithium through investigating its prescribing and monitoring patterns in both inpatients and outpatients at Fort England Hospital. Methodology: The study was in the form of a retrospective DUR. Data was collected from 40 files (n=40) of patients who were on treatment with lithium between 1 January 2017-31 December 2017 at Fort England Hospital. The data was collected retrospectively for both in- and outpatients. Compliance of the monitoring requirements with both South African and international guidelines was analysed. Results and Discussion: In 87.50% (n=37) of the cases, patients had been on lithium therapy before 2017 with most patients (n=13; 37.50%) being maintained on 500 mg of lithium. Non-compliance with the South African and NICE guidelines for renal baseline monitoring was 65.00% (n=26) in both guidelines. Non-compliance for baseline thyroid monitoring was 70.00% (n=28) for both guidelines. There was non-compliance in 45.00% (n=18) of the cases for lithium serum level monitoring for both guidelines. Non-compliance with follow-up renal monitoring was 47.50% (n=19) for both guidelines. Compliance with the NICE guidelines for follow-up metabolic monitoring was 67.50% (n=27). Conclusion: There was non-compliance in most cases leaving room for clinical improvement in the monitoring of lithium. Healthcare professionals should be educated on the recommended monitoring guidelines to promote the rational use of lithium in South Africa. Pharmacists should be more involved in the TDM of lithium to promote its safe and effective use.
- Full Text:
- Date Issued: 2020-04
- Authors: Mapfumo, Charlotte
- Date: 2020-04
- Subjects: Lithium -- Therapeutic use , Psychiatric hospitals -- South Africa -- Grahamstown , Drug utilization , Psychiatric hospital care , Manic-depressive illness , Lithium -- Toxicology , Drug monitoring
- Language: English
- Type: text , Thesis , Masters , M.Pharm
- Identifier: http://hdl.handle.net/10962/150541 , vital:38983
- Description: Bipolar disorder (BD) is a common mental condition that affects about 60 million people globally. Lithium is among the drugs of choice used to treat BD and other affective disorders such as schizoaffective disorder (SD). Lithium is a mood stabiliser with antimanic, antidepressant and anti-suicidal properties. Lithium has complex mechanisms of action and a narrow therapeutic index (NTI). Therapeutic drug monitoring (TDM) is a vital component of lithium therapy due to its NTI. Lithium toxicity can occur at therapeutic levels and is characterised by symptoms such as blurred vision and convulsions. Lithium interacts with a number of drugs resulting in lithium toxicity or diminished effects of lithium. Symptoms of lithium toxicity range from abdominal pain, convulsions and death. Lithium use is associated with serious adverse effects on renal and thyroid function. Other adverse effects include tremor and weight gain. Monitoring of lithium serum levels, renal and thyroid function are therefore recommended for patients on lithium therapy. Monitoring of these parameters assists in the early detection of any problems associated with lithium use. The metabolic monitoring of lithium is vital due to the adverse effect profile of lithium and the current South African Standard Treatment Guidelines Hospital level: Adults, do not have any recommendations for the monitoring of metabolic parameters. The National Institute for Health and Care Excellence (NICE) may be used and adapted for the South African setting. Aim and Objectives: The general aim of the study was to conduct a drug utilisation review (DUR) on lithium through investigating its prescribing and monitoring patterns in both inpatients and outpatients at Fort England Hospital. Methodology: The study was in the form of a retrospective DUR. Data was collected from 40 files (n=40) of patients who were on treatment with lithium between 1 January 2017-31 December 2017 at Fort England Hospital. The data was collected retrospectively for both in- and outpatients. Compliance of the monitoring requirements with both South African and international guidelines was analysed. Results and Discussion: In 87.50% (n=37) of the cases, patients had been on lithium therapy before 2017 with most patients (n=13; 37.50%) being maintained on 500 mg of lithium. Non-compliance with the South African and NICE guidelines for renal baseline monitoring was 65.00% (n=26) in both guidelines. Non-compliance for baseline thyroid monitoring was 70.00% (n=28) for both guidelines. There was non-compliance in 45.00% (n=18) of the cases for lithium serum level monitoring for both guidelines. Non-compliance with follow-up renal monitoring was 47.50% (n=19) for both guidelines. Compliance with the NICE guidelines for follow-up metabolic monitoring was 67.50% (n=27). Conclusion: There was non-compliance in most cases leaving room for clinical improvement in the monitoring of lithium. Healthcare professionals should be educated on the recommended monitoring guidelines to promote the rational use of lithium in South Africa. Pharmacists should be more involved in the TDM of lithium to promote its safe and effective use.
- Full Text:
- Date Issued: 2020-04
A double-edged sword : the minimum wage and agrarian labour in the Eastern Cape, South Africa, 2003–2014
- Authors: Naidoo, Lalitha
- Date: 2021-04
- Subjects: Minimum wage -- South Africa -- Eastern Cape , Agricultural laborers -- South Africa -- Eastern Cape , Labor laws and legislation -- South Africa , Agricultural wages -- South Africa -- Eastern Cape , Agricultural laborers -- South Africa -- Eastern Cape -- Social conditions , Agricultural laborers -- Legal status, laws, etc. -- South Africa -- Eastern Cape , Agricultural laws and legislation -- South Africa -- Eastern Cape , Work environment -- South Africa -- Eastern Cape , Economics -- Sociological aspects , South Africa -- Politics and government -- 1994-
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177111 , vital:42791 , 10.21504/10962/177115
- Description: Statutory wage setting and the extension of labour laws to the South African agrarian labour market are path-breaking events that altered the unilateral power which agrarian employers had, under apartheid, to set low wages and harsh employment conditions. Yet, economic sociologists have shown little interest in the agrarian minimum wage in South Africa. Consequently, little to no sociological perspectives are available on the way in which statutory wages shape the setting of actual agrarian wages, employment conditions, labour relations and working and living conditions. At the same time, economic sociology’s neglect of agrarian minimum wages perpetuates the dominance of economics in minimum wage research, as well as the narrow cost-benefit analysis, and firm and employer-centric focus, deployed by both opponents of minimum wages in the neoclassical economics camp and supporters in the heterodox economics camp. The firm-centric focus also applies to the few labour relations scholars who focus on minimum wages. As a result, a wide body of empirical information is available and concentrated in the Global North, on low-waged, urban-based firms’ employment and labour relations strategies with the occasioning of minimum wage laws, with scant to non-existing information on rural-based workers’ experiences in the Global South, at least in the case of South Africa. This thesis addresses the lacuna in existing research, specifically by concentrating on agrarian workers’ narratives of the outcomes of minimum wages on actual wages and conditions, and experiences at the site of production and in the sphere of expanded social reproduction. The conceptual framework of the thesis is rooted in a critical realist meta-theory which directs inquiry towards the search for underlying causes of events with a sensitivity to the interaction of structure and agency, so as to develop explanations of events, which in turn encourage emancipatory thought and praxis. Within this framework, a political economy perspective of the agrarian minimum wage is charted, founded on an inter-disciplinary approach that incorporates economic sociology perspectives, which view markets as socio-political constructs, alongside a Marxist analysis of wages and the distinction between the value of labour and the value of labour power. Also relevant are segmentation labour market models where the focus is on segmentation in labour supply, demand and regulation, and institutional economics that highlights labour’s weak bargaining power in low-waged labour markets. Based on this analytical perspective, the South African agrarian minimum wage is seen as a necessary intervention stemming from post-apartheid uneven neoliberal restructuring processes, to address extremely low agrarian wages that pose threats to the ongoing generation of agrarian labour power. Low agrarian wages are located in unequal power relations in the workplace and are embedded in the totality of the low-waged agrarian labour market, composed of particular features in the supply-side of the labour market (the sphere of social reproduction of labour), the demand-side of the labour market (the site of production), and the forces of regulation (the labour relations regime). The thesis explores new ways of conceptualising minimum wages in the South African context, placing emphasis on the local agrarian labour market, and it highlights the agency of agrarian labour by revealing their struggles, working life and living conditions. In so doing, the research expands inquiry beyond economic “impact” at the level of the firm/employer to examine: (a) workers’ employment trends before and after the minimum wage was introduced, (b) the extent of changes in working and living conditions and labour relations, (c) the scope for workers in animating changes and their struggles and challenges, and (d) shifts in actual wages in relation to prescribed wage rates. Focussing on the aforementioned aspects represents an attempt in this thesis to build on themes, raised in heterodox economics studies, of minimum wages and their relationship to the social devaluation of low-waged work, inequalities in bargaining power, and justice. Based on a stratified sample of workers that included, among other variables, sex, geographical area and agricultural sub-sectors, original data was collected through 52 in-depth interviews, two focus group interviews (comprised of 10 workers), and 501 surveyed workers. The research did not find widespread job losses when minimum wages were introduced, as per neoclassical economics’ predictions. Nor did it find transitions from low- to high-road approaches in employment strategies and labour relations, as claimed by certain heterodox economists. Instead, the findings at the sites of production corroborate the uneven, mixed and contradictory findings of applied heterodox minimum wage studies on employment strategies, labour relations and wage settings. In this light, it is concluded that the agrarian minimum wage had layered outcomes for workers based on key findings, which include: (a) the minimum wage became the maximum wage as actual wages increased and clustered at the prescribed wage rate; (b) a level of gender wage parity close to the level of the prevailing prescribed minimum wage was found, but an overall gendered pattern to low-waged employment surfaced and manifested differently at sub-sector and enterprise levels; (c) though no changes were found in the way work was organised and how workers executed their tasks alongside no fundamental changes in the social relations of production, statutory minimum wages and limitations on working hours did reduce the hours of work and the existence of unpaid overtime work in certain sub-sectors such as livestock and dairy workplaces, through worker and employer initiatives (yet, at the same time, work intensification in compressed working hours appeared in the sample in other worksites, for example citrus workplaces); (d) authoritarian labour relations existed in varying depths and forms, based on sub-sector and enterprise characteristics, which shaped the propensity and scope for worker action; and (e) the layered outcomes of the agrarian minimum wage were felt at the site of social reproduction, where it brought a measure of relief for sampled workers; however, it was chronically inadequate to allow workers to meet their subsistence needs comprehensively. The research findings also highlight sub-sectoral complexities in changing employment and labour relations strategies from low- to high-road approaches in the agrarian sector. The layered outcomes of minimum wages for agrarian workers stems from the combined and uneven amalgamation of pre-existing and new conditions and relations consequent to neoliberalising processes in the agrarian political economy as well as the low minimum wage-setting. The thesis thus argues that the mixed outcomes reflect the layered character of the minimum wage as a conversion factor, which in turn equates to a layered notion of justice. This is because, on the one hand, the minimum wage ameliorates the plight of agrarian labour but, on the other hand, and given the bulwark of authoritarianism, pre-existing conditions and neoliberalising processes, the collective vulnerabilities in the agrarian labour market have expanded and may be intensifying. The agrarian minimum wage acts as a double-edged sword in contexts of mixed and layered outcomes for agrarian labour. A layered perspective of the conversion factor of a minimum wage exposes the possibilities and limitations of statutory wages as a conversion factor, based on context, and identifies the limits and possibilities for worker mobilisation and action. In the case of this research, the agrarian minimum wage deals in limited fashion with the value of labour power because of the initial and subsequent low settings; the minimum wage does not deal with class exploitation and the value of labour, although it sets the frame for instigating basic labour standards. The implications of a layered conversion potential of low minimum wage-settings are profound for conceptualising, theorising and researching the link between statutory wages and justice, with respect to the value of labour power and the value of labour. Future research on the minimum wage based on a Marxist reading of wages and located in real labour markets, strengthens heterodox approaches by deepening theories on the relationship between statutory wages, justice and production. , Thesis (PhD) -- Faculty of Humanities, Department of Sociology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Naidoo, Lalitha
- Date: 2021-04
- Subjects: Minimum wage -- South Africa -- Eastern Cape , Agricultural laborers -- South Africa -- Eastern Cape , Labor laws and legislation -- South Africa , Agricultural wages -- South Africa -- Eastern Cape , Agricultural laborers -- South Africa -- Eastern Cape -- Social conditions , Agricultural laborers -- Legal status, laws, etc. -- South Africa -- Eastern Cape , Agricultural laws and legislation -- South Africa -- Eastern Cape , Work environment -- South Africa -- Eastern Cape , Economics -- Sociological aspects , South Africa -- Politics and government -- 1994-
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177111 , vital:42791 , 10.21504/10962/177115
- Description: Statutory wage setting and the extension of labour laws to the South African agrarian labour market are path-breaking events that altered the unilateral power which agrarian employers had, under apartheid, to set low wages and harsh employment conditions. Yet, economic sociologists have shown little interest in the agrarian minimum wage in South Africa. Consequently, little to no sociological perspectives are available on the way in which statutory wages shape the setting of actual agrarian wages, employment conditions, labour relations and working and living conditions. At the same time, economic sociology’s neglect of agrarian minimum wages perpetuates the dominance of economics in minimum wage research, as well as the narrow cost-benefit analysis, and firm and employer-centric focus, deployed by both opponents of minimum wages in the neoclassical economics camp and supporters in the heterodox economics camp. The firm-centric focus also applies to the few labour relations scholars who focus on minimum wages. As a result, a wide body of empirical information is available and concentrated in the Global North, on low-waged, urban-based firms’ employment and labour relations strategies with the occasioning of minimum wage laws, with scant to non-existing information on rural-based workers’ experiences in the Global South, at least in the case of South Africa. This thesis addresses the lacuna in existing research, specifically by concentrating on agrarian workers’ narratives of the outcomes of minimum wages on actual wages and conditions, and experiences at the site of production and in the sphere of expanded social reproduction. The conceptual framework of the thesis is rooted in a critical realist meta-theory which directs inquiry towards the search for underlying causes of events with a sensitivity to the interaction of structure and agency, so as to develop explanations of events, which in turn encourage emancipatory thought and praxis. Within this framework, a political economy perspective of the agrarian minimum wage is charted, founded on an inter-disciplinary approach that incorporates economic sociology perspectives, which view markets as socio-political constructs, alongside a Marxist analysis of wages and the distinction between the value of labour and the value of labour power. Also relevant are segmentation labour market models where the focus is on segmentation in labour supply, demand and regulation, and institutional economics that highlights labour’s weak bargaining power in low-waged labour markets. Based on this analytical perspective, the South African agrarian minimum wage is seen as a necessary intervention stemming from post-apartheid uneven neoliberal restructuring processes, to address extremely low agrarian wages that pose threats to the ongoing generation of agrarian labour power. Low agrarian wages are located in unequal power relations in the workplace and are embedded in the totality of the low-waged agrarian labour market, composed of particular features in the supply-side of the labour market (the sphere of social reproduction of labour), the demand-side of the labour market (the site of production), and the forces of regulation (the labour relations regime). The thesis explores new ways of conceptualising minimum wages in the South African context, placing emphasis on the local agrarian labour market, and it highlights the agency of agrarian labour by revealing their struggles, working life and living conditions. In so doing, the research expands inquiry beyond economic “impact” at the level of the firm/employer to examine: (a) workers’ employment trends before and after the minimum wage was introduced, (b) the extent of changes in working and living conditions and labour relations, (c) the scope for workers in animating changes and their struggles and challenges, and (d) shifts in actual wages in relation to prescribed wage rates. Focussing on the aforementioned aspects represents an attempt in this thesis to build on themes, raised in heterodox economics studies, of minimum wages and their relationship to the social devaluation of low-waged work, inequalities in bargaining power, and justice. Based on a stratified sample of workers that included, among other variables, sex, geographical area and agricultural sub-sectors, original data was collected through 52 in-depth interviews, two focus group interviews (comprised of 10 workers), and 501 surveyed workers. The research did not find widespread job losses when minimum wages were introduced, as per neoclassical economics’ predictions. Nor did it find transitions from low- to high-road approaches in employment strategies and labour relations, as claimed by certain heterodox economists. Instead, the findings at the sites of production corroborate the uneven, mixed and contradictory findings of applied heterodox minimum wage studies on employment strategies, labour relations and wage settings. In this light, it is concluded that the agrarian minimum wage had layered outcomes for workers based on key findings, which include: (a) the minimum wage became the maximum wage as actual wages increased and clustered at the prescribed wage rate; (b) a level of gender wage parity close to the level of the prevailing prescribed minimum wage was found, but an overall gendered pattern to low-waged employment surfaced and manifested differently at sub-sector and enterprise levels; (c) though no changes were found in the way work was organised and how workers executed their tasks alongside no fundamental changes in the social relations of production, statutory minimum wages and limitations on working hours did reduce the hours of work and the existence of unpaid overtime work in certain sub-sectors such as livestock and dairy workplaces, through worker and employer initiatives (yet, at the same time, work intensification in compressed working hours appeared in the sample in other worksites, for example citrus workplaces); (d) authoritarian labour relations existed in varying depths and forms, based on sub-sector and enterprise characteristics, which shaped the propensity and scope for worker action; and (e) the layered outcomes of the agrarian minimum wage were felt at the site of social reproduction, where it brought a measure of relief for sampled workers; however, it was chronically inadequate to allow workers to meet their subsistence needs comprehensively. The research findings also highlight sub-sectoral complexities in changing employment and labour relations strategies from low- to high-road approaches in the agrarian sector. The layered outcomes of minimum wages for agrarian workers stems from the combined and uneven amalgamation of pre-existing and new conditions and relations consequent to neoliberalising processes in the agrarian political economy as well as the low minimum wage-setting. The thesis thus argues that the mixed outcomes reflect the layered character of the minimum wage as a conversion factor, which in turn equates to a layered notion of justice. This is because, on the one hand, the minimum wage ameliorates the plight of agrarian labour but, on the other hand, and given the bulwark of authoritarianism, pre-existing conditions and neoliberalising processes, the collective vulnerabilities in the agrarian labour market have expanded and may be intensifying. The agrarian minimum wage acts as a double-edged sword in contexts of mixed and layered outcomes for agrarian labour. A layered perspective of the conversion factor of a minimum wage exposes the possibilities and limitations of statutory wages as a conversion factor, based on context, and identifies the limits and possibilities for worker mobilisation and action. In the case of this research, the agrarian minimum wage deals in limited fashion with the value of labour power because of the initial and subsequent low settings; the minimum wage does not deal with class exploitation and the value of labour, although it sets the frame for instigating basic labour standards. The implications of a layered conversion potential of low minimum wage-settings are profound for conceptualising, theorising and researching the link between statutory wages and justice, with respect to the value of labour power and the value of labour. Future research on the minimum wage based on a Marxist reading of wages and located in real labour markets, strengthens heterodox approaches by deepening theories on the relationship between statutory wages, justice and production. , Thesis (PhD) -- Faculty of Humanities, Department of Sociology, 2021
- Full Text:
- Date Issued: 2021-04
A distributed Linda server on a network of heterogeneous processors
- Authors: Smith, Graham Leslie
- Date: 1993
- Subjects: LINDA (Computer system) , Parallel programming (Computer science)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4610 , http://hdl.handle.net/10962/d1004890 , LINDA (Computer system) , Parallel programming (Computer science)
- Description: Linda is an approach to parallelism which relies on a virtual associative shared memory called tuple space. Tuple space is accessed through a small set of primitive operations and is conceptually easy to understand and manipulate. The physical implementation of a Linda tuple space may of course be completely different from the conceptual model. Rhodes has implemented versions of Linda on a ring of RS-232 joined PC's and on a cluster of T800 transputers with a single copy of tuple space on one transputer. Current research targets the implementation of a distributed Linda server on a network of heterogeneous processors. This work describes the design and implementation of a distributed Linda server. Emphasis is placed on aspects of the design which enhance portability and efficiency.
- Full Text:
- Date Issued: 1993
- Authors: Smith, Graham Leslie
- Date: 1993
- Subjects: LINDA (Computer system) , Parallel programming (Computer science)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4610 , http://hdl.handle.net/10962/d1004890 , LINDA (Computer system) , Parallel programming (Computer science)
- Description: Linda is an approach to parallelism which relies on a virtual associative shared memory called tuple space. Tuple space is accessed through a small set of primitive operations and is conceptually easy to understand and manipulate. The physical implementation of a Linda tuple space may of course be completely different from the conceptual model. Rhodes has implemented versions of Linda on a ring of RS-232 joined PC's and on a cluster of T800 transputers with a single copy of tuple space on one transputer. Current research targets the implementation of a distributed Linda server on a network of heterogeneous processors. This work describes the design and implementation of a distributed Linda server. Emphasis is placed on aspects of the design which enhance portability and efficiency.
- Full Text:
- Date Issued: 1993
A distributed approach to surround sound production
- Authors: Smith, Adrian Wilfrid
- Date: 1999
- Subjects: Surround-sound systems , Computer sound processing , Music -- Data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4602 , http://hdl.handle.net/10962/d1004855 , Surround-sound systems , Computer sound processing , Music -- Data processing
- Description: The requirement for multi-channel surround sound in audio production applications is growing rapidly. Audio processing in these applications can be costly, particularly in multi-channel systems. A distributed approach is proposed for the development of a realtime spatialization system for surround sound music production, using Ambisonic surround sound methods. The latency in the system is analyzed, with a focus on the audio processing and network delays, in order to ascertain the feasibility of an enhanced, distributed real-time spatialization system.
- Full Text:
- Date Issued: 1999
- Authors: Smith, Adrian Wilfrid
- Date: 1999
- Subjects: Surround-sound systems , Computer sound processing , Music -- Data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4602 , http://hdl.handle.net/10962/d1004855 , Surround-sound systems , Computer sound processing , Music -- Data processing
- Description: The requirement for multi-channel surround sound in audio production applications is growing rapidly. Audio processing in these applications can be costly, particularly in multi-channel systems. A distributed approach is proposed for the development of a realtime spatialization system for surround sound music production, using Ambisonic surround sound methods. The latency in the system is analyzed, with a focus on the audio processing and network delays, in order to ascertain the feasibility of an enhanced, distributed real-time spatialization system.
- Full Text:
- Date Issued: 1999
A distributed approach to leadership in an academic department in a South African university: an exploratory case study
- Authors: Haufiku, Kenneth David
- Date: 2023-10-13
- Subjects: Universities and colleges Administration , Education, Higher South Africa , Distributed leadership , College department heads South Africa , School management and organization South Africa , Group decision making
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419748 , vital:71672
- Description: The Head of Department (HOD) position at a university has traditionally been viewed as an individual construct. However, due to the demanding nature of such a position, it is not sought-after, as it remains exclusive and unappealing to many academics. Moreover, it is a position that does not encourage inclusive leadership. Tension and role ambiguity are known to arise between the scholarly project on the one hand and management and administrative matters on the other. To address challenges associated with this singular leadership position, an academic department at a South African university adopted a distributed leadership approach in their department as a research experiment. My study was based on this research experiment. I designed this research as an exploratory case study, guided by a socio-cultural conceptualisation of distributed leadership that included a leader-plus and a practice aspect, defined as a product of the interactions of school leaders, followers and their situation. This qualitative case study aimed to describe and explain how a distributed leadership approach was understood and practised in an academic department. It also investigated the enablements and constraints of the approach. Data were generated through document analysis, observation, and individual and focus group interviews. The participants in this study included the departmental leadership team and the department’s academic and administrative staff. Unfortunately, my study took place during the global COVID-19 pandemic and national lockdowns. I had no choice but to adapt my data generation methods due to lockdown restrictions. As a result, most data generation was done via online communication. The study used inductive and abductive analysis to make the data meaningful to the reader. The findings revealed that different participants had different ideas about distributed leadership. Distributed leadership was understood as a socio-cultural practice rather than an individual practice with multiple leaders in relational practice. In addition, this approach was understood as a way of developing and sharing expertise by encouraging teamwork, collegiality and collective decision-making which aligns with the notion of democratic decision-making which creates a platform for the enablement of leadership in others. The study further explored how distributed leadership was practised. The findings were that the HOD position, usually a one-person role, was reconceptualised as a HOD team comprised of three academics and the departmental administrator. The HOD team divided the work among themselves, and this was done according to each individual’s expertise. In addition, leadership within the academic department was not limited to the HOD team but stretched across the department; thus, multiple leaders were evident. Therefore, based on the data, this study discovered that a distributed approach values leadership expertise in others. Consequently, it can be used to promote an inclusive environment in which any organisation member can lead. Inclusivity in the decision-making process was also regarded as a strong practice in the academic department. As a result, this study contends that those in formal positions can develop leadership in others through a distributed leadership approach. Through that, lecturer leadership was enacted through formal faculty and university structures and informally as and when the situation required it. The enablements of this departmental leadership approach included the structural innovation of the Friday check-in as well as the buddy system. These two innovations provided the space for collegiality and the development of voice and leadership. The consultative nature of the HOD team was also viewed as an enablement. Certain factors constrained the distributed leadership approach, one of which was the tension between the hierarchical structure of the university and the more horizontal, distributed leadership approach being piloted in the academic department. In addition to that, another constraint was also very real with the transition to Zoom as an online teaching, learning and supervision platform as a consequence of the COVID-19 pandemic. The final constraint was experienced concerning the department’s history, as it was within a historically White university in South Africa. The effects of this history impacted the departmental culture and, as we know from the literature, institutional culture is extremely difficult to change. Finally, the study concluded that conceptualising distributed leadership as a sociocultural practice with leader-plus and practice aspects provides descriptive language and a solid theoretical and analytical framework for a distributed leadership study. The study makes an important knowledge contribution in the African Higher Education context as limited research has been carried out in this area. Furthermore, in terms of practice, my study serves as a stimulus for leadership discussions that are beneficial to everyone involved in educational institutions as they promote a level of leadership reflexivity, currently absent in many institutions. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Haufiku, Kenneth David
- Date: 2023-10-13
- Subjects: Universities and colleges Administration , Education, Higher South Africa , Distributed leadership , College department heads South Africa , School management and organization South Africa , Group decision making
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419748 , vital:71672
- Description: The Head of Department (HOD) position at a university has traditionally been viewed as an individual construct. However, due to the demanding nature of such a position, it is not sought-after, as it remains exclusive and unappealing to many academics. Moreover, it is a position that does not encourage inclusive leadership. Tension and role ambiguity are known to arise between the scholarly project on the one hand and management and administrative matters on the other. To address challenges associated with this singular leadership position, an academic department at a South African university adopted a distributed leadership approach in their department as a research experiment. My study was based on this research experiment. I designed this research as an exploratory case study, guided by a socio-cultural conceptualisation of distributed leadership that included a leader-plus and a practice aspect, defined as a product of the interactions of school leaders, followers and their situation. This qualitative case study aimed to describe and explain how a distributed leadership approach was understood and practised in an academic department. It also investigated the enablements and constraints of the approach. Data were generated through document analysis, observation, and individual and focus group interviews. The participants in this study included the departmental leadership team and the department’s academic and administrative staff. Unfortunately, my study took place during the global COVID-19 pandemic and national lockdowns. I had no choice but to adapt my data generation methods due to lockdown restrictions. As a result, most data generation was done via online communication. The study used inductive and abductive analysis to make the data meaningful to the reader. The findings revealed that different participants had different ideas about distributed leadership. Distributed leadership was understood as a socio-cultural practice rather than an individual practice with multiple leaders in relational practice. In addition, this approach was understood as a way of developing and sharing expertise by encouraging teamwork, collegiality and collective decision-making which aligns with the notion of democratic decision-making which creates a platform for the enablement of leadership in others. The study further explored how distributed leadership was practised. The findings were that the HOD position, usually a one-person role, was reconceptualised as a HOD team comprised of three academics and the departmental administrator. The HOD team divided the work among themselves, and this was done according to each individual’s expertise. In addition, leadership within the academic department was not limited to the HOD team but stretched across the department; thus, multiple leaders were evident. Therefore, based on the data, this study discovered that a distributed approach values leadership expertise in others. Consequently, it can be used to promote an inclusive environment in which any organisation member can lead. Inclusivity in the decision-making process was also regarded as a strong practice in the academic department. As a result, this study contends that those in formal positions can develop leadership in others through a distributed leadership approach. Through that, lecturer leadership was enacted through formal faculty and university structures and informally as and when the situation required it. The enablements of this departmental leadership approach included the structural innovation of the Friday check-in as well as the buddy system. These two innovations provided the space for collegiality and the development of voice and leadership. The consultative nature of the HOD team was also viewed as an enablement. Certain factors constrained the distributed leadership approach, one of which was the tension between the hierarchical structure of the university and the more horizontal, distributed leadership approach being piloted in the academic department. In addition to that, another constraint was also very real with the transition to Zoom as an online teaching, learning and supervision platform as a consequence of the COVID-19 pandemic. The final constraint was experienced concerning the department’s history, as it was within a historically White university in South Africa. The effects of this history impacted the departmental culture and, as we know from the literature, institutional culture is extremely difficult to change. Finally, the study concluded that conceptualising distributed leadership as a sociocultural practice with leader-plus and practice aspects provides descriptive language and a solid theoretical and analytical framework for a distributed leadership study. The study makes an important knowledge contribution in the African Higher Education context as limited research has been carried out in this area. Furthermore, in terms of practice, my study serves as a stimulus for leadership discussions that are beneficial to everyone involved in educational institutions as they promote a level of leadership reflexivity, currently absent in many institutions. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2023
- Full Text:
- Date Issued: 2023-10-13
A discussion of the concept, “place of effective management” and the proposed changes, in the context of South African tax law
- Authors: Singh, Nishika
- Date: 2016
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/4166 , vital:20629
- Description: The concept, “place of effective management”, is used in South African tax legislation to determine the residency of companies and it is also used by the Organisation for Economic Co-operation and Development (OECD) and in many tax treaties as a tie-breaker clause to determine the residency of companies that may appear to be dual resident or to determine which country has the taxing rights to income that may be subject to double tax due to the income being from a source outside of the company’s country of residence. The concept is not defined in any tax legislation and there is no uniform interpretation of the concept globally. The former guidance provided by the South African Revenue Services (SARS) adopted a hierarchal approach and the focus was the implementation of the Board of Directors’ decisions. This interpretation was not aligned to the guidance of the OECD whose focus is the place where the key management and commercial decisions of the entity are made. The current SARS guidance has been aligned to the OECD guidance and, essentially, the core principle is to determine who makes the key commercial and management decisions of the company and the place where these individuals are making these decisions. The current SARS and OECD guidance have now been aligned. The current SARS and OECD interpretations have been found to be a more effective tie-breaker clause than the former interpretations.
- Full Text:
- Date Issued: 2016
- Authors: Singh, Nishika
- Date: 2016
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/4166 , vital:20629
- Description: The concept, “place of effective management”, is used in South African tax legislation to determine the residency of companies and it is also used by the Organisation for Economic Co-operation and Development (OECD) and in many tax treaties as a tie-breaker clause to determine the residency of companies that may appear to be dual resident or to determine which country has the taxing rights to income that may be subject to double tax due to the income being from a source outside of the company’s country of residence. The concept is not defined in any tax legislation and there is no uniform interpretation of the concept globally. The former guidance provided by the South African Revenue Services (SARS) adopted a hierarchal approach and the focus was the implementation of the Board of Directors’ decisions. This interpretation was not aligned to the guidance of the OECD whose focus is the place where the key management and commercial decisions of the entity are made. The current SARS guidance has been aligned to the OECD guidance and, essentially, the core principle is to determine who makes the key commercial and management decisions of the company and the place where these individuals are making these decisions. The current SARS and OECD guidance have now been aligned. The current SARS and OECD interpretations have been found to be a more effective tie-breaker clause than the former interpretations.
- Full Text:
- Date Issued: 2016
A discussion and comparison of company legislation and tax legislation in South Africa, in relation to amalgamations and mergers
- Authors: Sloane, Justin
- Date: 2014
- Subjects: Corporation law -- South Africa , Taxation -- Law and legislation -- South Africa , Consolidation and merger of corporations -- South Africa , Income tax -- South Africa , Capital gains tax -- South Africa , Value-added tax -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:908 , http://hdl.handle.net/10962/d1013028
- Description: In his 2012 Budget Review, the Minister of Finance, Pravin Gordhan acknowledged that the introduction of the "new" Companies Act had given rise to certain anomalies in relation to tax and subsequently announced that the South African government would undertake to review the nature of company mergers, acquisitions and other restructurings with the view of possibly amending the Income Tax Act and/or the "new" Companies Act, to bring the two legislations in line with one another. These anomalies give rise to the present research. The literature reviewed in the present research revealed and identified the inconsistencies that exist between the "new" Companies Act, 71 of 2008 and the Income Tax Act, 58 of 1962, specifically the inconsistencies that exist in respect of the newly introduced amalgamation or merger provisions as set out in the "new" Companies Act. Moreover, this research was undertaken to identify the potential tax implications insofar as they relate to amalgamation transactions and, in particular, the potential tax implications where such transactions, because of the anomalies, fall outside the ambit section 44 of the Income Tax Act, which would in normal circumstances provide for tax "rollover relief". In this regard, the present research identified the possible income tax, capital gains tax, value-added tax, transfer duty tax and securities transfer tax affected by an amalgamation transaction, on the assumption that the "rollover relief" in section 44 of the Income Tax Act does not apply.
- Full Text:
- Date Issued: 2014
- Authors: Sloane, Justin
- Date: 2014
- Subjects: Corporation law -- South Africa , Taxation -- Law and legislation -- South Africa , Consolidation and merger of corporations -- South Africa , Income tax -- South Africa , Capital gains tax -- South Africa , Value-added tax -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:908 , http://hdl.handle.net/10962/d1013028
- Description: In his 2012 Budget Review, the Minister of Finance, Pravin Gordhan acknowledged that the introduction of the "new" Companies Act had given rise to certain anomalies in relation to tax and subsequently announced that the South African government would undertake to review the nature of company mergers, acquisitions and other restructurings with the view of possibly amending the Income Tax Act and/or the "new" Companies Act, to bring the two legislations in line with one another. These anomalies give rise to the present research. The literature reviewed in the present research revealed and identified the inconsistencies that exist between the "new" Companies Act, 71 of 2008 and the Income Tax Act, 58 of 1962, specifically the inconsistencies that exist in respect of the newly introduced amalgamation or merger provisions as set out in the "new" Companies Act. Moreover, this research was undertaken to identify the potential tax implications insofar as they relate to amalgamation transactions and, in particular, the potential tax implications where such transactions, because of the anomalies, fall outside the ambit section 44 of the Income Tax Act, which would in normal circumstances provide for tax "rollover relief". In this regard, the present research identified the possible income tax, capital gains tax, value-added tax, transfer duty tax and securities transfer tax affected by an amalgamation transaction, on the assumption that the "rollover relief" in section 44 of the Income Tax Act does not apply.
- Full Text:
- Date Issued: 2014
A discursive analysis of what sexual violence perpetrators say to their victims
- Authors: Coopoo, Perishka
- Date: 2017
- Subjects: Project Unbreakable , Rapists -- Language , Rape -- Social aspects , Language and sex , Sexual harassment of women , Women -- Crimes against , Discoure analysis
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/13869 , vital:21863
- Description: This research study aimed to examine the way in which sexual violence perpetrators talk to their victims by critically investigating the discursive strategies drawn on by perpetrators, the discursive constructions of their actions and their victims, and the consistencies with the talk of sexual violence perpetrators and rape myths and discursive and social practices promoting sexual violence. Over two-hundred photographs were collected from a photographic art project called Project Unbreakable. The photographs were of sexual violence survivors, from all over the world, holding a poster with a quote from their attacker. The words that survivors chose to represent for Project Unbreakable served as the data for this research study. The data were analyzed using the six stages of Foucauldian discourse analysis outlined by Carla Willig. The analysis revealed that by drawing on discourses of pleasure, desire, romance, marriage and consent, perpetrators discursively constructed their actions as sex. Furthermore, perpetrators discursively constructed their victims as sexually passive and dependant on men, as gate keepers of men’s sexuality, as sexual instruments for male satisfaction, and as consenting persons. On the other hand, perpetrators were also found to discursively construct their actions as a legitimized form of punishment, humiliation and intimidation. In addition, their victims were discursively constructed as deviant, deserving of their victimization, worthless, damaged and powerless. These discursive constructions of their actions and their victims enabled perpetrators to normalize their behaviour, blame their victims, minimize the incident, assert their innocence, justify their actions, silence their victims and reinforce their position at the top of the gender hierarchy. Consistencies were also found between the talk of perpetrators and rape myths, stereotypes and discursive and social practices promoting sexual violence. Another interesting finding in the data was that of quotes from a third party, not the perpetrator, which further illustrated the existence of rape culture. This research draws on the idea that a rape supportive culture does not only capture the hostile nature of the social environment that many survivors experience in the aftermath of sexual violence, but it also provides a social pattern for coercive sexuality to occur.
- Full Text:
- Date Issued: 2017
- Authors: Coopoo, Perishka
- Date: 2017
- Subjects: Project Unbreakable , Rapists -- Language , Rape -- Social aspects , Language and sex , Sexual harassment of women , Women -- Crimes against , Discoure analysis
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/13869 , vital:21863
- Description: This research study aimed to examine the way in which sexual violence perpetrators talk to their victims by critically investigating the discursive strategies drawn on by perpetrators, the discursive constructions of their actions and their victims, and the consistencies with the talk of sexual violence perpetrators and rape myths and discursive and social practices promoting sexual violence. Over two-hundred photographs were collected from a photographic art project called Project Unbreakable. The photographs were of sexual violence survivors, from all over the world, holding a poster with a quote from their attacker. The words that survivors chose to represent for Project Unbreakable served as the data for this research study. The data were analyzed using the six stages of Foucauldian discourse analysis outlined by Carla Willig. The analysis revealed that by drawing on discourses of pleasure, desire, romance, marriage and consent, perpetrators discursively constructed their actions as sex. Furthermore, perpetrators discursively constructed their victims as sexually passive and dependant on men, as gate keepers of men’s sexuality, as sexual instruments for male satisfaction, and as consenting persons. On the other hand, perpetrators were also found to discursively construct their actions as a legitimized form of punishment, humiliation and intimidation. In addition, their victims were discursively constructed as deviant, deserving of their victimization, worthless, damaged and powerless. These discursive constructions of their actions and their victims enabled perpetrators to normalize their behaviour, blame their victims, minimize the incident, assert their innocence, justify their actions, silence their victims and reinforce their position at the top of the gender hierarchy. Consistencies were also found between the talk of perpetrators and rape myths, stereotypes and discursive and social practices promoting sexual violence. Another interesting finding in the data was that of quotes from a third party, not the perpetrator, which further illustrated the existence of rape culture. This research draws on the idea that a rape supportive culture does not only capture the hostile nature of the social environment that many survivors experience in the aftermath of sexual violence, but it also provides a social pattern for coercive sexuality to occur.
- Full Text:
- Date Issued: 2017
A discourse analysis of print media constructions of 'Muslim' people in British newspapers
- Authors: Nanabawa, Sumaiya
- Date: 2013
- Subjects: Muslims -- Great Britain -- Public opinion Islam -- Great Britain -- Public opinion Racism in mass media Mass media -- Political aspects -- Great Britain Mass media -- Social aspects -- Great Britain Journalism -- Social aspects Journalism, Commercial -- Great Britain
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3132 , http://hdl.handle.net/10962/d1006767
- Description: This research study aimed to examine how the identity of ' Muslim' people is constructed in British print media today, and whether or not these constructions promote or undermine a xeno-racist project. The research draws on the idea that identity is partly constructed through representation, with an emphasis on how language can be used to construct and position people in different ways. Using a social constructionist paradigm, the study further considers the role that print media has in providing a discursive field within which the construction and reproduction of racist attitudes and ideologies in contemporary global society can take place. Sixty-five newspaper articles were selected from the online archives of British newspapers, The Guardian and The Daily Telegraph using systematic random sampling. These were analysed using the six stages of Foucauldian discourse analysis outlined by Carla Willig. To provide a more fruitful account, the analysis also incorporated the methods of Potter and Wetherell whose focus is on the function of discourse, as well as van Langenhove and Harre's focus on subject positioning, and Parker's use of Foucauldian analysis which looks at power distributions. The analysis revealed that Muslims are discursively constructed as a direct politicised or terror threat, often drawing on discourses of sharia law, and Muslim-Christian relationships. They are also constructed as a cultural threat, drawing on discourses of isolation, oppressed women, the veil/headscarf, identity, visibility and integration. The analysis also showed some variation in constructions, and these extended from the racialization of Muslims to showing the compatibility between Islamic and western values. This study discusses the form these different constructions take and the possible implications these constructions might have in contributing toward a prejudiced and largely negative image of Islam and Muslims.
- Full Text:
- Date Issued: 2013
- Authors: Nanabawa, Sumaiya
- Date: 2013
- Subjects: Muslims -- Great Britain -- Public opinion Islam -- Great Britain -- Public opinion Racism in mass media Mass media -- Political aspects -- Great Britain Mass media -- Social aspects -- Great Britain Journalism -- Social aspects Journalism, Commercial -- Great Britain
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3132 , http://hdl.handle.net/10962/d1006767
- Description: This research study aimed to examine how the identity of ' Muslim' people is constructed in British print media today, and whether or not these constructions promote or undermine a xeno-racist project. The research draws on the idea that identity is partly constructed through representation, with an emphasis on how language can be used to construct and position people in different ways. Using a social constructionist paradigm, the study further considers the role that print media has in providing a discursive field within which the construction and reproduction of racist attitudes and ideologies in contemporary global society can take place. Sixty-five newspaper articles were selected from the online archives of British newspapers, The Guardian and The Daily Telegraph using systematic random sampling. These were analysed using the six stages of Foucauldian discourse analysis outlined by Carla Willig. To provide a more fruitful account, the analysis also incorporated the methods of Potter and Wetherell whose focus is on the function of discourse, as well as van Langenhove and Harre's focus on subject positioning, and Parker's use of Foucauldian analysis which looks at power distributions. The analysis revealed that Muslims are discursively constructed as a direct politicised or terror threat, often drawing on discourses of sharia law, and Muslim-Christian relationships. They are also constructed as a cultural threat, drawing on discourses of isolation, oppressed women, the veil/headscarf, identity, visibility and integration. The analysis also showed some variation in constructions, and these extended from the racialization of Muslims to showing the compatibility between Islamic and western values. This study discusses the form these different constructions take and the possible implications these constructions might have in contributing toward a prejudiced and largely negative image of Islam and Muslims.
- Full Text:
- Date Issued: 2013
A discourse analysis of media representation of women political leaders in Uganda
- Authors: Kemirembe, Grace
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408908 , vital:70536
- Description: This study is a qualitative desktop research project. The study employed a Feminist Critical Discourse Analysis to analyse and unpack the discursive ways in which female politicians are discussed and talked about in Ugandan online media. This study was a response to the realisation that online media portrayals of female politicians in Uganda remain largely unexplored. Additionally, the study discovered that the Daily Monitor and The Observer, the two newspapers that this thesis researched, often employ gender stereotypes and sexist coverage of female politicians in Uganda using personalisation, trivialisation and demonisation frames. The study illustrates that these misogynistic frames are intended to diminish women’s importance in the political sphere. Moreover, women who do not conform to the gender stereotypes are portrayed as social deviants. This work concludes that one of the challenges faced by women politicians in Uganda, and in Africa as a whole, is how to exploit online media’s productive capacity while, at the same time, resisting its use as an instrument that undermines them. Given the limited scope of the study using only two media organisations, future studies on media representation of female politicians could expand the range to include print and visual sources to provide generalisable results. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Kemirembe, Grace
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408908 , vital:70536
- Description: This study is a qualitative desktop research project. The study employed a Feminist Critical Discourse Analysis to analyse and unpack the discursive ways in which female politicians are discussed and talked about in Ugandan online media. This study was a response to the realisation that online media portrayals of female politicians in Uganda remain largely unexplored. Additionally, the study discovered that the Daily Monitor and The Observer, the two newspapers that this thesis researched, often employ gender stereotypes and sexist coverage of female politicians in Uganda using personalisation, trivialisation and demonisation frames. The study illustrates that these misogynistic frames are intended to diminish women’s importance in the political sphere. Moreover, women who do not conform to the gender stereotypes are portrayed as social deviants. This work concludes that one of the challenges faced by women politicians in Uganda, and in Africa as a whole, is how to exploit online media’s productive capacity while, at the same time, resisting its use as an instrument that undermines them. Given the limited scope of the study using only two media organisations, future studies on media representation of female politicians could expand the range to include print and visual sources to provide generalisable results. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2023
- Full Text:
- Date Issued: 2023-03-30
A difficult equilibrium: torture narratives and the ethics of reciprocity in apartheid South Africa and its aftermath
- Authors: Pett, Sarah
- Date: 2009
- Subjects: Apartheid -- South Africa -- History Torture -- South Africa Post-apartheid era -- South Africa Apartheid in literature Torture in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2194 , http://hdl.handle.net/10962/d1002236
- Description: This thesis takes the form of an enquiry into the development of the ―generic contours (Bakhtin 4) for the narration of torture in South Africa during apartheid and its aftermath. The enquiry focusses on the ethical determinations that underlie the conventions of this genre. My theoretical framework uses Adam Zachary Newton‘s conceptualization of narrative ethics to supplement Paul Ricoeur‘s writings on narrative identity and the ethical intention, thus facilitating the transfer of Ricoeur‘s abstract philosophy to the realm of literary criticism. Part I presents torture as a disruption of narrative identity and a defamiliarization of the intersubjective encounter. The existence of torture narratives thus attests to the critical role of narration in the reconstruction of the tortured person‘s identity and the re-establishment of benign frameworks of intersubjective communication. Literature‘s potential to act as a laboratory for the testing of the limitations of narrative identity and the resilience of ethical mores suggests that the fictional representation of torture also has an important role to play in this attempt at rehabilitation. Part II takes the form of a comparative analysis of non-fictional and fictional accounts of torture originating from apartheid South Africa. This shows that the ethical determinations underlying the narration of torture in South Africa range from intersubjective estrangement to a ―solicitude of reciprocity (Bourgeois 109). However, because the majority of these texts used the presentation of human rights abuses to galvanize international opposition to apartheid, the scope for experimentation was limited by the political exigencies of the time. Part III examines the stylistic and generic shifts in the narration of torture that accompanied South Africa‘s transition to democracy. It suggests that the discursive dominance of the Truth and Reconciliation Commission replaced the fruitful—in literary terms—dialogue between authoritarianism and resistance that characterized the apartheid era with a monologic grand narrative of emotional catharsis, reconciliation and nation building. It also suggests that the ―truth-and-reconciliation genre of writing (Quayson 754) that shaped the literary milieu of the post-TRC period be seen in terms of a resurgence of the apartheid–era paradigms for the narration of human rights abuses that were repressed during the initial phase of democratic transition. By framing the TRC as a catalyst for individual journeys of self-discovery, these novels raise important questions about what it means to be a part of the ―new South Africa. In contrast to the majority of apartheid era literature, the novels of the post-TRC period privilege the literary prerogative over the political, and thus bring to fruition the experimental potential of the previous paradigm. In doing so, they not only go beyond solicitude to achieve an ―authentic reciprocity in exchange (Ricoeur, Oneself 191), but also initiate a process of long-awaited literary expansion, in which authors look beyond the limits of apartheid and begin to critically engage with the region‘s pre-apartheid history and its post-apartheid present.
- Full Text:
- Date Issued: 2009
- Authors: Pett, Sarah
- Date: 2009
- Subjects: Apartheid -- South Africa -- History Torture -- South Africa Post-apartheid era -- South Africa Apartheid in literature Torture in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2194 , http://hdl.handle.net/10962/d1002236
- Description: This thesis takes the form of an enquiry into the development of the ―generic contours (Bakhtin 4) for the narration of torture in South Africa during apartheid and its aftermath. The enquiry focusses on the ethical determinations that underlie the conventions of this genre. My theoretical framework uses Adam Zachary Newton‘s conceptualization of narrative ethics to supplement Paul Ricoeur‘s writings on narrative identity and the ethical intention, thus facilitating the transfer of Ricoeur‘s abstract philosophy to the realm of literary criticism. Part I presents torture as a disruption of narrative identity and a defamiliarization of the intersubjective encounter. The existence of torture narratives thus attests to the critical role of narration in the reconstruction of the tortured person‘s identity and the re-establishment of benign frameworks of intersubjective communication. Literature‘s potential to act as a laboratory for the testing of the limitations of narrative identity and the resilience of ethical mores suggests that the fictional representation of torture also has an important role to play in this attempt at rehabilitation. Part II takes the form of a comparative analysis of non-fictional and fictional accounts of torture originating from apartheid South Africa. This shows that the ethical determinations underlying the narration of torture in South Africa range from intersubjective estrangement to a ―solicitude of reciprocity (Bourgeois 109). However, because the majority of these texts used the presentation of human rights abuses to galvanize international opposition to apartheid, the scope for experimentation was limited by the political exigencies of the time. Part III examines the stylistic and generic shifts in the narration of torture that accompanied South Africa‘s transition to democracy. It suggests that the discursive dominance of the Truth and Reconciliation Commission replaced the fruitful—in literary terms—dialogue between authoritarianism and resistance that characterized the apartheid era with a monologic grand narrative of emotional catharsis, reconciliation and nation building. It also suggests that the ―truth-and-reconciliation genre of writing (Quayson 754) that shaped the literary milieu of the post-TRC period be seen in terms of a resurgence of the apartheid–era paradigms for the narration of human rights abuses that were repressed during the initial phase of democratic transition. By framing the TRC as a catalyst for individual journeys of self-discovery, these novels raise important questions about what it means to be a part of the ―new South Africa. In contrast to the majority of apartheid era literature, the novels of the post-TRC period privilege the literary prerogative over the political, and thus bring to fruition the experimental potential of the previous paradigm. In doing so, they not only go beyond solicitude to achieve an ―authentic reciprocity in exchange (Ricoeur, Oneself 191), but also initiate a process of long-awaited literary expansion, in which authors look beyond the limits of apartheid and begin to critically engage with the region‘s pre-apartheid history and its post-apartheid present.
- Full Text:
- Date Issued: 2009
A dielectric and spectroscopic study of molecular association in solutions of alcohols
- Authors: Campbell, Colin
- Date: 1975
- Subjects: Alcohols , Dielectrics , Spectrum analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4454 , http://hdl.handle.net/10962/d1010424
- Description: This study is concerned with the association characteristics of solutions of alcohols in some non-polar solvents. The permittivities at 2 MHz and 25°C for solutions of the straight chain octanols in cyclohexane, carbon tetrachloride and benzene have been examined over the entire solute concentration range, with particular attention -1 being paid to the range below 0.1 molℓ⁻¹ By applying the Kirkwood- Fröhlich equation to these data, the apparent dipole moments of the alcohols as a function of concentration have been evaluated. These concentration dependencies have been correlated with infrared absorption results on the same systems to provide information on the sizes and configurations of the proposed hydrogen bonded multimers. It is concluded that, at very low solute concentrations, the alcohol molecules exist as monomers; but with increasing concentration, two types of hydrogen bonded multimers are formed, the first (at low concentrations) being of high dipole moment and the second (at higher concentrations) being of low dipole moment. At high concentrations, the molecules associate to form a three-dimensional network. Attempts have been made to determine equilibrium parameters for molecular models which are consistent with the qualitative understanding of the association behaviour. These parameters were obtained by applying least-squares, curve-fitting techniques to the low concentration permittivity data. A similar investigation has been conducted on solutions of 2,3,4-trimethyl-3-pentanol in the same solvents. The steric hindrance around the hydroxyl group of this alcohol modifies the association behaviour so that a three-dimensional network does not form at high solute concentrations. Proton magnetic resonance chemical shifts for the hydroxyl proton of this alcohol in carbon tetrachloride solutions have been measured. Attempts have also been made to determine equilibrium parameters which describe formation of the hydrogen bonded multimers. To extend this study to include solutes other than octanols, similar experiments have been conducted on solutions of t-butanol in hexadecane, a system which has recently been investigated by other workers using different experimental techniques. The association behaviour of this system is qualitatively similar to that of the straight-chain octanols. The combination of permittivity and infrared measurements, although proving extremely powerful in interpreting the association characteristics of dilute alcohol solutions, is less adequate at high solute concentrations. Attention was therefore directed towards dielectric relaxation and viscosity studies to investigate concentrated solutions. The relaxation times at 20°C of the low frequency dispersion have been measured for solutions of 1-propanol, 1-butanol, 1-hexanol, 1-octanol and 1-decanol in cyclohexane using time domain reflectometry techniques. Similar measurements have also been made on solutions of 1-butanol and 1-octanol in carbon tetrachloride and in benzene. The concentration dependence of the viscosities of certain of these systems has also been examined in an independent study. The ratio of the dielectric relaxation time to the viscosity, the "reduced relaxation time", is qualitatively similar for each system studied. This similarity leads to an explanation of the molecular process responsible for the low frequency dispersion in terms of the proximity of the hydroxyl groups in concentrated alcohol solutions and the fraction of the groups which are not involved in hydrogen bonding.
- Full Text:
- Date Issued: 1975
- Authors: Campbell, Colin
- Date: 1975
- Subjects: Alcohols , Dielectrics , Spectrum analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4454 , http://hdl.handle.net/10962/d1010424
- Description: This study is concerned with the association characteristics of solutions of alcohols in some non-polar solvents. The permittivities at 2 MHz and 25°C for solutions of the straight chain octanols in cyclohexane, carbon tetrachloride and benzene have been examined over the entire solute concentration range, with particular attention -1 being paid to the range below 0.1 molℓ⁻¹ By applying the Kirkwood- Fröhlich equation to these data, the apparent dipole moments of the alcohols as a function of concentration have been evaluated. These concentration dependencies have been correlated with infrared absorption results on the same systems to provide information on the sizes and configurations of the proposed hydrogen bonded multimers. It is concluded that, at very low solute concentrations, the alcohol molecules exist as monomers; but with increasing concentration, two types of hydrogen bonded multimers are formed, the first (at low concentrations) being of high dipole moment and the second (at higher concentrations) being of low dipole moment. At high concentrations, the molecules associate to form a three-dimensional network. Attempts have been made to determine equilibrium parameters for molecular models which are consistent with the qualitative understanding of the association behaviour. These parameters were obtained by applying least-squares, curve-fitting techniques to the low concentration permittivity data. A similar investigation has been conducted on solutions of 2,3,4-trimethyl-3-pentanol in the same solvents. The steric hindrance around the hydroxyl group of this alcohol modifies the association behaviour so that a three-dimensional network does not form at high solute concentrations. Proton magnetic resonance chemical shifts for the hydroxyl proton of this alcohol in carbon tetrachloride solutions have been measured. Attempts have also been made to determine equilibrium parameters which describe formation of the hydrogen bonded multimers. To extend this study to include solutes other than octanols, similar experiments have been conducted on solutions of t-butanol in hexadecane, a system which has recently been investigated by other workers using different experimental techniques. The association behaviour of this system is qualitatively similar to that of the straight-chain octanols. The combination of permittivity and infrared measurements, although proving extremely powerful in interpreting the association characteristics of dilute alcohol solutions, is less adequate at high solute concentrations. Attention was therefore directed towards dielectric relaxation and viscosity studies to investigate concentrated solutions. The relaxation times at 20°C of the low frequency dispersion have been measured for solutions of 1-propanol, 1-butanol, 1-hexanol, 1-octanol and 1-decanol in cyclohexane using time domain reflectometry techniques. Similar measurements have also been made on solutions of 1-butanol and 1-octanol in carbon tetrachloride and in benzene. The concentration dependence of the viscosities of certain of these systems has also been examined in an independent study. The ratio of the dielectric relaxation time to the viscosity, the "reduced relaxation time", is qualitatively similar for each system studied. This similarity leads to an explanation of the molecular process responsible for the low frequency dispersion in terms of the proximity of the hydroxyl groups in concentrated alcohol solutions and the fraction of the groups which are not involved in hydrogen bonding.
- Full Text:
- Date Issued: 1975
A development method for deriving reusable concurrent programs from verified CSP models
- Authors: Dibley, James
- Date: 2019
- Subjects: CSP (Computer program language) , Sequential processing (Computer science) , Go (Computer program language) , CSPIDER (Open source tool)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/72329 , vital:30035
- Description: This work proposes and demonstrates a novel method for software development that applies formal verification techniques to the design and implementation of concurrent programs. This method is supported by a new software tool, CSPIDER, which translates machine-readable Communicating Sequential Processes (CSP) models into encapsulated, reusable components coded in the Go programming language. In relation to existing CSP implementation techniques, this work is only the second to implement a translator and it provides original support for some CSP language constructs and modelling approaches. The method is evaluated through three case studies: a concurrent sorting array, a trialdivision prime number generator, and a component node for the Ricart-Agrawala distributed mutual exclusion algorithm. Each of these case studies presents the formal verification of safety and functional requirements through CSP model-checking, and it is shown that CSPIDER is capable of generating reusable implementations from each model. The Ricart-Agrawala case study demonstrates the application of the method to the design of a protocol component. This method maintains full compatibility with the primary CSP verification tool. Applying the CSPIDER tool requires minimal commitment to an explicitly defined modelling style and a very small set of pre-translation annotations, but all of these measures can be instated prior to verification. The Go code that CSPIDER produces requires no intervention before it may be used as a component within a larger development. The translator provides a traceable, structured implementation of the CSP model, automatically deriving formal parameters and a channel-based client interface from its interpretation of the CSP model. Each case study demonstrates the use of the translated component within a simple test development.
- Full Text:
- Date Issued: 2019
- Authors: Dibley, James
- Date: 2019
- Subjects: CSP (Computer program language) , Sequential processing (Computer science) , Go (Computer program language) , CSPIDER (Open source tool)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/72329 , vital:30035
- Description: This work proposes and demonstrates a novel method for software development that applies formal verification techniques to the design and implementation of concurrent programs. This method is supported by a new software tool, CSPIDER, which translates machine-readable Communicating Sequential Processes (CSP) models into encapsulated, reusable components coded in the Go programming language. In relation to existing CSP implementation techniques, this work is only the second to implement a translator and it provides original support for some CSP language constructs and modelling approaches. The method is evaluated through three case studies: a concurrent sorting array, a trialdivision prime number generator, and a component node for the Ricart-Agrawala distributed mutual exclusion algorithm. Each of these case studies presents the formal verification of safety and functional requirements through CSP model-checking, and it is shown that CSPIDER is capable of generating reusable implementations from each model. The Ricart-Agrawala case study demonstrates the application of the method to the design of a protocol component. This method maintains full compatibility with the primary CSP verification tool. Applying the CSPIDER tool requires minimal commitment to an explicitly defined modelling style and a very small set of pre-translation annotations, but all of these measures can be instated prior to verification. The Go code that CSPIDER produces requires no intervention before it may be used as a component within a larger development. The translator provides a traceable, structured implementation of the CSP model, automatically deriving formal parameters and a channel-based client interface from its interpretation of the CSP model. Each case study demonstrates the use of the translated component within a simple test development.
- Full Text:
- Date Issued: 2019