A comparison of muscle fatigue responses between static and quasi-static exertions
- Authors: Nel, Conrad
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3475 , vital:20502
- Description: Background: This study examined localized muscle fatigue responses from sub-maximal quasi-static work protocols and additionally how it compares to purely static work. The goal was to produce research that enhances the understanding of the demands on muscles during manual work to aid in preventing injuries stemming from localized muscle fatigue. Injury rates remain a problem in manual labour sectors, particularly for the lower back and shoulder regions for the manufacturing, service and construction sectors, and for knee and elbow flexors in the sports sector. Few studies have looked at quasi-static work and what the resulting fatigue characteristics are, especially when compared to purely static or purely dynamic work. This comparison is particularly important due to the fact that risk assessment tools that are currently utilized to assess risk in the working environment are based on fatigue studies that focus on purely static or purely dynamic work. This requires attention as many working situations are neither static nor dynamic, but rather quasi-static in nature, with aspects of both dynamic and static muscle components. The scope of this study only encompasses the comparison between purely static and quasi-static work. Objectives: This study had two objectives, firstly, to determine what the fatigue characteristics of quasi-static work are and how it compares to fully static work. Secondly, to determine whether an underlying static component within an otherwise dynamic muscle force affects localized muscle fatigue compared to quasi-static work that has equal amounts of effort but with no underlying static component. Methods: Four experimental conditions were tested, each on four muscles, namely the medial deltoid, bicep brachii, bicep femoris and erector spinae muscles. To test the two objectives of this study, 16 volunteers performed a five minute fatigue protocol, that either entailed a fully static condition which involved: 1) producing a steady force at 25 percent of maximum voluntary force, 2) a quasi-static condition with fully dynamic muscle force that alternates the required force level between zero and 50 percent of maximum force, 3) a quasi-static condition with an underlying static component of five percent of maximum force, or 4) a quasi-static condition with a large underlying static component of 15 percent of maximum force. All the experimental conditions in this study had the same average workload of 25 percent of maximum voluntary force over time and thus total workload. The dependant variables of interest were ratings of perceived exertion, changes in muscle fibre recruitment (% of maximum EMG activity), maximum force and center frequency from a spectral analysis of the surface electromyography. These were measured throughout the protocols at one minute intervals to determine how muscle fatigue progressed, and how the fatigue responses differed between conditions. Results: The data from comparing fully static and quasi-static work showed that of the variables measured, the rating of perceived exertion (RPE) and maximum force data indicated that for bicep brachii and bicep femoris muscles, fully static work is more fatiguing than work that alternates between zero and 50 percent of maximum force. The results for the medial deltoid and erector spinae muscles were inconclusive. The findings regarding the comparison between quasi-static conditions with and without an underlying static component revealed that an underlying static component results in greater fatigue when compared to a quasi-static condition with no static component. The results may also suggest that a larger static component coupled with a smaller peak force results in less fatigue than a condition with a small underlying static component coupled with a higher peak force in some scenarios, provided total work is kept constant. All conditions had to have the same workload in order to be validly compared and thus the condition with a larger underlying static component had a lower peak force compared to the condition with no underlying static component or the condition with a small underlying static component. Conclusions: This study presented evidence that quasi-static work does not induce fatigue when measured by RPE and drop in maximum force in the same way as static work. Additionally, the results indicate that a larger underlying static component does not necessarily fatigue a muscle faster if the overall workload is kept constant. However, the results do suggest that any underlying static component will increase the demand on a muscle when compared to a muscle exertion with no static component. When considering the available literature on how muscles fatigue during low level static contractions, the current understanding is that the larger the force during a static contraction, the faster the onset of fatigue and decrements in performance occur. The results of this study suggest that this same relationship cannot be applied to quasi-static work where an underlying static component is part of an otherwise dynamic muscle force. Thus total workload or peak force may play a larger role than the static muscle exertion in some scenarios.
- Full Text:
- Date Issued: 2016
- Authors: Nel, Conrad
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3475 , vital:20502
- Description: Background: This study examined localized muscle fatigue responses from sub-maximal quasi-static work protocols and additionally how it compares to purely static work. The goal was to produce research that enhances the understanding of the demands on muscles during manual work to aid in preventing injuries stemming from localized muscle fatigue. Injury rates remain a problem in manual labour sectors, particularly for the lower back and shoulder regions for the manufacturing, service and construction sectors, and for knee and elbow flexors in the sports sector. Few studies have looked at quasi-static work and what the resulting fatigue characteristics are, especially when compared to purely static or purely dynamic work. This comparison is particularly important due to the fact that risk assessment tools that are currently utilized to assess risk in the working environment are based on fatigue studies that focus on purely static or purely dynamic work. This requires attention as many working situations are neither static nor dynamic, but rather quasi-static in nature, with aspects of both dynamic and static muscle components. The scope of this study only encompasses the comparison between purely static and quasi-static work. Objectives: This study had two objectives, firstly, to determine what the fatigue characteristics of quasi-static work are and how it compares to fully static work. Secondly, to determine whether an underlying static component within an otherwise dynamic muscle force affects localized muscle fatigue compared to quasi-static work that has equal amounts of effort but with no underlying static component. Methods: Four experimental conditions were tested, each on four muscles, namely the medial deltoid, bicep brachii, bicep femoris and erector spinae muscles. To test the two objectives of this study, 16 volunteers performed a five minute fatigue protocol, that either entailed a fully static condition which involved: 1) producing a steady force at 25 percent of maximum voluntary force, 2) a quasi-static condition with fully dynamic muscle force that alternates the required force level between zero and 50 percent of maximum force, 3) a quasi-static condition with an underlying static component of five percent of maximum force, or 4) a quasi-static condition with a large underlying static component of 15 percent of maximum force. All the experimental conditions in this study had the same average workload of 25 percent of maximum voluntary force over time and thus total workload. The dependant variables of interest were ratings of perceived exertion, changes in muscle fibre recruitment (% of maximum EMG activity), maximum force and center frequency from a spectral analysis of the surface electromyography. These were measured throughout the protocols at one minute intervals to determine how muscle fatigue progressed, and how the fatigue responses differed between conditions. Results: The data from comparing fully static and quasi-static work showed that of the variables measured, the rating of perceived exertion (RPE) and maximum force data indicated that for bicep brachii and bicep femoris muscles, fully static work is more fatiguing than work that alternates between zero and 50 percent of maximum force. The results for the medial deltoid and erector spinae muscles were inconclusive. The findings regarding the comparison between quasi-static conditions with and without an underlying static component revealed that an underlying static component results in greater fatigue when compared to a quasi-static condition with no static component. The results may also suggest that a larger static component coupled with a smaller peak force results in less fatigue than a condition with a small underlying static component coupled with a higher peak force in some scenarios, provided total work is kept constant. All conditions had to have the same workload in order to be validly compared and thus the condition with a larger underlying static component had a lower peak force compared to the condition with no underlying static component or the condition with a small underlying static component. Conclusions: This study presented evidence that quasi-static work does not induce fatigue when measured by RPE and drop in maximum force in the same way as static work. Additionally, the results indicate that a larger underlying static component does not necessarily fatigue a muscle faster if the overall workload is kept constant. However, the results do suggest that any underlying static component will increase the demand on a muscle when compared to a muscle exertion with no static component. When considering the available literature on how muscles fatigue during low level static contractions, the current understanding is that the larger the force during a static contraction, the faster the onset of fatigue and decrements in performance occur. The results of this study suggest that this same relationship cannot be applied to quasi-static work where an underlying static component is part of an otherwise dynamic muscle force. Thus total workload or peak force may play a larger role than the static muscle exertion in some scenarios.
- Full Text:
- Date Issued: 2016
A comparison of nesting behaviour and prey selection in some Southern African species of Ammophila (Hymenoptera : Sphecidae)
- Authors: Weaving, Alan James Shelley
- Date: 1987
- Subjects: Hymenoptera
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5600 , http://hdl.handle.net/10962/d1002050
- Description: Nesting behaviour and prey selection was compared in eight species of Ammophila. The frequent sympatry of these species was a central point of interest in the study. Nest siting differed markedly in several species. A. ferrugineipes, A. dolichodera, A. dolichocephala and, probably, A. conifera nested mostly in open habitats, this being regarded as the most common situation for the majority of Ammophila. A. beniniensis was unusual in nesting in well vegetated habitats, A. vulcania doing so amongst small clumps of vegetation in otherwise open habitats. A. insignis nested in vertical banks or old animal burrows and A. braunsi utilised abandoned burrows of other wasps situated in non-friable clay soils. This is the first time such nest siting has been reported for Ammophila and each of these two species is consequently unique. Many aspects of nest construction behaviour, in particular methods of soil waste disposal, sealing of nests and their final coverage, differed interspecifically, in some cases intraspecifically, but often apparently in response to the habitat. With regard to nest provisioning strategies, all species hunted after digging their nests, except A. dolichodera which is the first Afrotropical Ammophila reported to hunt before excavating its nest. This brings the total number of the world's species of Ammophila showing this behaviour to three. This species, A. beniniensis, A. braunsi and A. vulcania provided one caterpillar per nest; the others supplied several, A. insignis being the only mass provisioner. A. ferrugineipes showed a form of progressive provisioning and maintained several nests at a time; it is the only Afrotropical species known so far to do so. Only two extra-limital species have been reported showing similar behaviour. The observed variations in provisioning strategies can most easily be explained in relation to the habitat. Investigation of prey selection showed that there was very little interspecific overlap in the species of caterpillars used for provisioning nests. This was shown to be due mainly to differing hunting habitat preferences. The various overall patterns of nesting behaviour, and variations in the different components within these patterns, were considered most likely to have resulted from allopatric speciation in different types of vegetation, the more advanced patterns arising in open habitats. The frequent occurrence of sympatry appears to be a reflection of a shifting distribution of mosaic patterns of vegetation types and the post-speciation spread of species. This influence of habitat on behaviour and prey selection has emphasised the need for caution in drawing phylogenetic conclusions from ethology. Further, these considerations provide an alternative to competition in attempting to explain the observed behaviour patterns and distribution of these wasps.
- Full Text:
- Date Issued: 1987
- Authors: Weaving, Alan James Shelley
- Date: 1987
- Subjects: Hymenoptera
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5600 , http://hdl.handle.net/10962/d1002050
- Description: Nesting behaviour and prey selection was compared in eight species of Ammophila. The frequent sympatry of these species was a central point of interest in the study. Nest siting differed markedly in several species. A. ferrugineipes, A. dolichodera, A. dolichocephala and, probably, A. conifera nested mostly in open habitats, this being regarded as the most common situation for the majority of Ammophila. A. beniniensis was unusual in nesting in well vegetated habitats, A. vulcania doing so amongst small clumps of vegetation in otherwise open habitats. A. insignis nested in vertical banks or old animal burrows and A. braunsi utilised abandoned burrows of other wasps situated in non-friable clay soils. This is the first time such nest siting has been reported for Ammophila and each of these two species is consequently unique. Many aspects of nest construction behaviour, in particular methods of soil waste disposal, sealing of nests and their final coverage, differed interspecifically, in some cases intraspecifically, but often apparently in response to the habitat. With regard to nest provisioning strategies, all species hunted after digging their nests, except A. dolichodera which is the first Afrotropical Ammophila reported to hunt before excavating its nest. This brings the total number of the world's species of Ammophila showing this behaviour to three. This species, A. beniniensis, A. braunsi and A. vulcania provided one caterpillar per nest; the others supplied several, A. insignis being the only mass provisioner. A. ferrugineipes showed a form of progressive provisioning and maintained several nests at a time; it is the only Afrotropical species known so far to do so. Only two extra-limital species have been reported showing similar behaviour. The observed variations in provisioning strategies can most easily be explained in relation to the habitat. Investigation of prey selection showed that there was very little interspecific overlap in the species of caterpillars used for provisioning nests. This was shown to be due mainly to differing hunting habitat preferences. The various overall patterns of nesting behaviour, and variations in the different components within these patterns, were considered most likely to have resulted from allopatric speciation in different types of vegetation, the more advanced patterns arising in open habitats. The frequent occurrence of sympatry appears to be a reflection of a shifting distribution of mosaic patterns of vegetation types and the post-speciation spread of species. This influence of habitat on behaviour and prey selection has emphasised the need for caution in drawing phylogenetic conclusions from ethology. Further, these considerations provide an alternative to competition in attempting to explain the observed behaviour patterns and distribution of these wasps.
- Full Text:
- Date Issued: 1987
A comparison of open source and proprietary digital forensic software
- Authors: Sonnekus, Michael Hendrik
- Date: 2015
- Subjects: Computer crimes , Computer crimes -- Investigation , Electronic evidence , Open source software
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4717 , http://hdl.handle.net/10962/d1017939
- Description: Scrutiny of the capabilities and accuracy of computer forensic tools is increasing as the number of incidents relying on digital evidence and the weight of that evidence increase. This thesis describes the capabilities of the leading proprietary and open source digital forensic tools. The capabilities of the tools were tested separately on digital media that had been formatted using Windows and Linux. Experiments were carried out with the intention of establishing whether the capabilities of open source computer forensics are similar to those of proprietary computer forensic tools, and whether these tools could complement one another. The tools were tested with regards to their capabilities to make and analyse digital forensic images in a forensically sound manner. The tests were carried out on each media type after deleting data from the media, and then repeated after formatting the media. The results of the experiments performed demonstrate that both proprietary and open source computer forensic tools have superior capabilities in different scenarios, and that the toolsets can be used to validate and complement one another. The implication of these findings is that investigators have an affordable means of validating their findings and are able to more effectively investigate digital media.
- Full Text:
- Date Issued: 2015
- Authors: Sonnekus, Michael Hendrik
- Date: 2015
- Subjects: Computer crimes , Computer crimes -- Investigation , Electronic evidence , Open source software
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4717 , http://hdl.handle.net/10962/d1017939
- Description: Scrutiny of the capabilities and accuracy of computer forensic tools is increasing as the number of incidents relying on digital evidence and the weight of that evidence increase. This thesis describes the capabilities of the leading proprietary and open source digital forensic tools. The capabilities of the tools were tested separately on digital media that had been formatted using Windows and Linux. Experiments were carried out with the intention of establishing whether the capabilities of open source computer forensics are similar to those of proprietary computer forensic tools, and whether these tools could complement one another. The tools were tested with regards to their capabilities to make and analyse digital forensic images in a forensically sound manner. The tests were carried out on each media type after deleting data from the media, and then repeated after formatting the media. The results of the experiments performed demonstrate that both proprietary and open source computer forensic tools have superior capabilities in different scenarios, and that the toolsets can be used to validate and complement one another. The implication of these findings is that investigators have an affordable means of validating their findings and are able to more effectively investigate digital media.
- Full Text:
- Date Issued: 2015
A comparison of representations of the imperative of higher education change as „transformation‟ versus „decolonisation‟ in South African public discourse
- Authors: Makgakge, Rebecca Dineo
- Date: 2020
- Subjects: Education in mass media -- South Africa , Higher education and state -- South Africa , Education, Higher -- Curricula -- South Africa , Discrimination in education -- South Africa , South Africa -- Colonial influence , Educational change -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/142498 , vital:38085
- Description: The context of higher education in South Africa which has been shaped by the legacies of the old apartheid system is faced with a paramount task of the continuous process of restructuring and change. In shaping the restructuring and change of the higher education system the concept of transformation has been a constant theme for the post-apartheid government policies. However more recently we have seen the heightened prominence of the concept of change understood as decolonisation of South African higher education – as opposed to “transformation‘. This thesis was concerned with how these concepts of change, “transformation‘ and “decolonisation‘ have been used in debates surrounding higher education in South Africa. The thesis compares and contrasts the ways and context in which they are used. This study of 177 South African newspaper articles taken form independent media stables from the time 2008 to the present provides an analysis of representations of higher education change as “transformation‘ and as “decolonisation‘ evinced in the corpus. This required using both content and framing analysis as a method to analyse the corpus. Three themes emerged from the analysis that are relevant to the comparison between South African higher education institutional change represented as “transformation‘ and South African higher education institutional change represented at “decolonisation‘: the first theme concerns the differences and similarities in how the two terms are defined; the second theme concerns how the two ideas play themselves out when it comes to curriculum change and the final theme concerns the implications of seeing change as “transformation‘ and seeing change as “decolonisation‘ for changing institutional cultures.
- Full Text:
- Date Issued: 2020
- Authors: Makgakge, Rebecca Dineo
- Date: 2020
- Subjects: Education in mass media -- South Africa , Higher education and state -- South Africa , Education, Higher -- Curricula -- South Africa , Discrimination in education -- South Africa , South Africa -- Colonial influence , Educational change -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/142498 , vital:38085
- Description: The context of higher education in South Africa which has been shaped by the legacies of the old apartheid system is faced with a paramount task of the continuous process of restructuring and change. In shaping the restructuring and change of the higher education system the concept of transformation has been a constant theme for the post-apartheid government policies. However more recently we have seen the heightened prominence of the concept of change understood as decolonisation of South African higher education – as opposed to “transformation‘. This thesis was concerned with how these concepts of change, “transformation‘ and “decolonisation‘ have been used in debates surrounding higher education in South Africa. The thesis compares and contrasts the ways and context in which they are used. This study of 177 South African newspaper articles taken form independent media stables from the time 2008 to the present provides an analysis of representations of higher education change as “transformation‘ and as “decolonisation‘ evinced in the corpus. This required using both content and framing analysis as a method to analyse the corpus. Three themes emerged from the analysis that are relevant to the comparison between South African higher education institutional change represented as “transformation‘ and South African higher education institutional change represented at “decolonisation‘: the first theme concerns the differences and similarities in how the two terms are defined; the second theme concerns how the two ideas play themselves out when it comes to curriculum change and the final theme concerns the implications of seeing change as “transformation‘ and seeing change as “decolonisation‘ for changing institutional cultures.
- Full Text:
- Date Issued: 2020
A comparison of the aquaculture potential of Clarias gariepinus (Burchell, 1822) and its hybrid with Heterobranchus longifilis valenciennes, 1840 in Southern Africa
- Authors: Oellermann, Lawrence Keith
- Date: 1996
- Subjects: Aquaculture -- South Africa Clarias Clariidae Catfishes -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5246 , http://hdl.handle.net/10962/d1005089
- Description: The aim of this study was to evaluate the aquaculture potential of a hybrid between the two largest African silurid catfish, Heterobranchus longifilis (HL) and Clarias gariepinus (CG) . A morphometric, meristic and karyological study showed that the hybrid shared some of the physical characteristics of both C. gariepinus and H. longifilis, while its chromosome complement and fundamental number (2N = 54, FN = 95), was intermediate between that of H. longifilis (2N = 52, FN = 92) and C. gariepinus (2N = 56, FN = 97). The HLxCG cross could therefore be regarded as a true hybrid. For the characters tested, no morphological or karyological differences were apparent between the HLxCG hybrids produced in West Africa and those produced in southern Africa. In southern Africa, the HL♂xCG♀ cross had higher fertilization and hatching rates than pure strain H. longifilis, C. gariepinus or the reverse cross. There was no difference in the survival of the HL♂xCG♀ hybrid larvae and C. gariepinus larvae up to the onset of exogenous feeding. Pure strain H. longifilis juveniles had a faster growth rate than the H. longifilis ♂ x C. gariepinus ♀ juveniles, but the hybrid always grew at a faster rate than C. gariepinus or the reverse cross. The HL♂xCG♀ cross was consequently chosen as the hybrid with the greatest potential for siluroid aquaculture in southern Africa. The HL♂xCG♀ hybrid showed evidence of partial gonadic, gametic and post-zygotic sterility in both sexes. The hybrid was not completely sterile, as it was artificially induced to spawn, and a small number of viable F₂ hybrid and F₁ hybrid x C. gariepinus larvae were produced. However, in the light of its probable reproductive strategy, it is highly unlikely that the hybrid would pose an ecological risk to the southern African region. The H. longifilis ♂ x C. gariepinus ♀ hybrid was compared to C. gariepinus for selected water quality preferences and tolerances. The hybrid had a wider temperature preference (28 °C to 34 °C) than C. gariepinus (28 °C to 30 °C), but appeared to be more dependent on aerial respiration than C. gariepinus. The air-breathing frequency of hybrid fish began to increase at dissolved oxygen concentrations below 3 .8 mg.ℓ⁻¹, while C. gariepinus only showed an increase in air-breathing frequency at concentrations below 3.0 mg.ℓ¹. The hybrid was more tolerant of un-ionised ammonia (96-hour LC₅₀ = 9.1 mg.ℓ⁻¹) than C. gariepinus (96-hour LC₅₀ = 6.5 mg.ℓ⁻¹), but their 96-hour LC₅₀ salinity tolerances were similar (10.8-11.0 g.ℓ⁻¹). The H. longifilis ♂ x C. gariepinus ♀ hybrid had a higher fillet yield (43.9 %) than C. gariepinus (38.9 %), but the crude protein content and amino acid profile of the two groups were similar. Catfish are traditionally grown in earthen ponds under semi-intensive conditions in southern Africa, at around 4 kg of fish per cubic meter of water (kg.m⁻³). However, the hybrid could tolerate densities of up to 415 kg of fish per cubic metre of water, if the water was exchanged hourly (kg.m⁻³.hr⁻¹), and the density at which yield was optimised was rounded off to 400 kg.m³.hr⁻¹. The high threshold density and water quality tolerances of the H. longifilis ♂ x C. gariepinus ♀ hybrid indicates that it is ideally suited for highly intensive aquaculture. It was concluded that it would be more productive to farm the HL♂xCG♀ hybrid on an intensive basis in southern Africa, than it would be to farm C. gariepinus in the traditional manner.
- Full Text:
- Date Issued: 1996
- Authors: Oellermann, Lawrence Keith
- Date: 1996
- Subjects: Aquaculture -- South Africa Clarias Clariidae Catfishes -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5246 , http://hdl.handle.net/10962/d1005089
- Description: The aim of this study was to evaluate the aquaculture potential of a hybrid between the two largest African silurid catfish, Heterobranchus longifilis (HL) and Clarias gariepinus (CG) . A morphometric, meristic and karyological study showed that the hybrid shared some of the physical characteristics of both C. gariepinus and H. longifilis, while its chromosome complement and fundamental number (2N = 54, FN = 95), was intermediate between that of H. longifilis (2N = 52, FN = 92) and C. gariepinus (2N = 56, FN = 97). The HLxCG cross could therefore be regarded as a true hybrid. For the characters tested, no morphological or karyological differences were apparent between the HLxCG hybrids produced in West Africa and those produced in southern Africa. In southern Africa, the HL♂xCG♀ cross had higher fertilization and hatching rates than pure strain H. longifilis, C. gariepinus or the reverse cross. There was no difference in the survival of the HL♂xCG♀ hybrid larvae and C. gariepinus larvae up to the onset of exogenous feeding. Pure strain H. longifilis juveniles had a faster growth rate than the H. longifilis ♂ x C. gariepinus ♀ juveniles, but the hybrid always grew at a faster rate than C. gariepinus or the reverse cross. The HL♂xCG♀ cross was consequently chosen as the hybrid with the greatest potential for siluroid aquaculture in southern Africa. The HL♂xCG♀ hybrid showed evidence of partial gonadic, gametic and post-zygotic sterility in both sexes. The hybrid was not completely sterile, as it was artificially induced to spawn, and a small number of viable F₂ hybrid and F₁ hybrid x C. gariepinus larvae were produced. However, in the light of its probable reproductive strategy, it is highly unlikely that the hybrid would pose an ecological risk to the southern African region. The H. longifilis ♂ x C. gariepinus ♀ hybrid was compared to C. gariepinus for selected water quality preferences and tolerances. The hybrid had a wider temperature preference (28 °C to 34 °C) than C. gariepinus (28 °C to 30 °C), but appeared to be more dependent on aerial respiration than C. gariepinus. The air-breathing frequency of hybrid fish began to increase at dissolved oxygen concentrations below 3 .8 mg.ℓ⁻¹, while C. gariepinus only showed an increase in air-breathing frequency at concentrations below 3.0 mg.ℓ¹. The hybrid was more tolerant of un-ionised ammonia (96-hour LC₅₀ = 9.1 mg.ℓ⁻¹) than C. gariepinus (96-hour LC₅₀ = 6.5 mg.ℓ⁻¹), but their 96-hour LC₅₀ salinity tolerances were similar (10.8-11.0 g.ℓ⁻¹). The H. longifilis ♂ x C. gariepinus ♀ hybrid had a higher fillet yield (43.9 %) than C. gariepinus (38.9 %), but the crude protein content and amino acid profile of the two groups were similar. Catfish are traditionally grown in earthen ponds under semi-intensive conditions in southern Africa, at around 4 kg of fish per cubic meter of water (kg.m⁻³). However, the hybrid could tolerate densities of up to 415 kg of fish per cubic metre of water, if the water was exchanged hourly (kg.m⁻³.hr⁻¹), and the density at which yield was optimised was rounded off to 400 kg.m³.hr⁻¹. The high threshold density and water quality tolerances of the H. longifilis ♂ x C. gariepinus ♀ hybrid indicates that it is ideally suited for highly intensive aquaculture. It was concluded that it would be more productive to farm the HL♂xCG♀ hybrid on an intensive basis in southern Africa, than it would be to farm C. gariepinus in the traditional manner.
- Full Text:
- Date Issued: 1996
A comparison of the effectiveness of the judicial doctrine of "substance over form" with legislated measures in combatting tax avoidance
- Authors: Weston, Tracey Lee
- Date: 2004
- Subjects: Income tax -- South Africa Income tax -- Law and legislation -- South Africa Income tax -- Law and legislation -- Great Britain Tax evasion -- Great Britain Tax evasion -- South Africa Tax administration and procedure -- South Africa Tax administration and procedure -- Great Britain Tax planning -- South Africa Tax planning -- Great Britain Taxation -- Law and legislation -- South Africa Taxation -- Law and legislation -- Great Britain
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:892 , http://hdl.handle.net/10962/100
- Description: Taxation statutes often provide opportunities for tax avoidance by taxpayers who exploit the provisions of the taxing statute to reduce the tax that they are legally required to pay. It is, however, important to distinguish between the concepts of tax avoidance and tax evasion. The central issue, especially where the contract has no business purpose, is whether it is possible for the substance and legal form of the transaction to differ to such an extent that a court of law will favour the substance rather than the legal format. The debate is whether the courts should be encouraged to continue with their "judge-made" law or whether the tax jurisdictions should be supporting a legislative route as opposed to a judicial one, in their efforts not only to combat tax avoidance but also to preserve taxpayer certainty. The question is whether the Doctrine of "Substance over Form" as applied by the judiciary is effective in combating tax avoidance, or whether a legislated general anti-avoidance provision is required. An intensive literature survey examines the changes which have occurred in the application of judicial tests from the 1930's to date and investigates the different approaches tax jurisdictions follow in order to combat tax avoidance. The effect of the introduction of anti-avoidance provisions in combating tax avoidance is evaluated by making a comparison between the United Kingdom and South Africa. [n the United Kingdom, the courts are relied on to create anti-tax avoidance rules, one of which is the Doctrine of "Substance over Form". The doctrine is very broad and identifies various applications of the doctrine, which have been developed by the courts. In South Africa, the Doctrine of "Substance over Form" has been applied in certain tax cases; however the South African Income Tax Act does include anti-tax avoidance sections aimed at specific tax avoidance schemes, as well as a general anti-tax avoidance measure enacted as section 103. The judicial tests have progressed and changed over time and the introduction of anti-avoidance legislation in the Income Tax Act has had an effect on tax planning opportunities. A distinction needs to be made between fraudulent and bona fide transactions while recognising the taxpayer's right to arrange his or her affairs in a manner which is beneficial to him or her from a tax perspective. Judicial activism and judicial legislation in the United Kingdom has created much uncertainty amongst taxpayers and as a result strongly supports the retention of a general anti-avoidance section within an Income Tax Act. A general anti-avoidance provision, following a legislative route, appears to be more consistent and effective in combating tax avoidance.
- Full Text:
- Date Issued: 2004
- Authors: Weston, Tracey Lee
- Date: 2004
- Subjects: Income tax -- South Africa Income tax -- Law and legislation -- South Africa Income tax -- Law and legislation -- Great Britain Tax evasion -- Great Britain Tax evasion -- South Africa Tax administration and procedure -- South Africa Tax administration and procedure -- Great Britain Tax planning -- South Africa Tax planning -- Great Britain Taxation -- Law and legislation -- South Africa Taxation -- Law and legislation -- Great Britain
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:892 , http://hdl.handle.net/10962/100
- Description: Taxation statutes often provide opportunities for tax avoidance by taxpayers who exploit the provisions of the taxing statute to reduce the tax that they are legally required to pay. It is, however, important to distinguish between the concepts of tax avoidance and tax evasion. The central issue, especially where the contract has no business purpose, is whether it is possible for the substance and legal form of the transaction to differ to such an extent that a court of law will favour the substance rather than the legal format. The debate is whether the courts should be encouraged to continue with their "judge-made" law or whether the tax jurisdictions should be supporting a legislative route as opposed to a judicial one, in their efforts not only to combat tax avoidance but also to preserve taxpayer certainty. The question is whether the Doctrine of "Substance over Form" as applied by the judiciary is effective in combating tax avoidance, or whether a legislated general anti-avoidance provision is required. An intensive literature survey examines the changes which have occurred in the application of judicial tests from the 1930's to date and investigates the different approaches tax jurisdictions follow in order to combat tax avoidance. The effect of the introduction of anti-avoidance provisions in combating tax avoidance is evaluated by making a comparison between the United Kingdom and South Africa. [n the United Kingdom, the courts are relied on to create anti-tax avoidance rules, one of which is the Doctrine of "Substance over Form". The doctrine is very broad and identifies various applications of the doctrine, which have been developed by the courts. In South Africa, the Doctrine of "Substance over Form" has been applied in certain tax cases; however the South African Income Tax Act does include anti-tax avoidance sections aimed at specific tax avoidance schemes, as well as a general anti-tax avoidance measure enacted as section 103. The judicial tests have progressed and changed over time and the introduction of anti-avoidance legislation in the Income Tax Act has had an effect on tax planning opportunities. A distinction needs to be made between fraudulent and bona fide transactions while recognising the taxpayer's right to arrange his or her affairs in a manner which is beneficial to him or her from a tax perspective. Judicial activism and judicial legislation in the United Kingdom has created much uncertainty amongst taxpayers and as a result strongly supports the retention of a general anti-avoidance section within an Income Tax Act. A general anti-avoidance provision, following a legislative route, appears to be more consistent and effective in combating tax avoidance.
- Full Text:
- Date Issued: 2004
A comparison of the female characters in Plautus and in Terence
- Authors: Slatter, E M
- Date: 1966
- Subjects: Plautus, Titus Maccius Terence Plautus, Titus Maccius -- Characters -- Women Terence -- Characters -- Women Latin drama Women in literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3602 , http://hdl.handle.net/10962/d1002186
- Full Text:
- Date Issued: 1966
- Authors: Slatter, E M
- Date: 1966
- Subjects: Plautus, Titus Maccius Terence Plautus, Titus Maccius -- Characters -- Women Terence -- Characters -- Women Latin drama Women in literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3602 , http://hdl.handle.net/10962/d1002186
- Full Text:
- Date Issued: 1966
A comparison of the legal environmental sustainability requirements of those engaging in the mining cycle, with actual practice in the Carolina X11B quaternary catchment, Mpumalanga, South Africa
- Authors: Thomson, Gareth Peter
- Date: 2018
- Subjects: Mineral industries Environmental aspects South Africa Mpumalanga , Acid mine drainage , Mineral industries Safety measures , Watersheds South Africa , South Africa. National Environmental Management Act, 1998 , Water-supply Law and legislation South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63481 , vital:28417
- Description: Mining is one of the most contentious water users. The mining sector has assumed that promises of economic growth and job creation will enable environmental concerns to be bypassed with as little interference as possible. More recently, the reality of legacy issues related to the inappropriate sign-off of mining sites has become increasingly clear, with acid mine drainage (AMD) being a prime example. There are also increasing concerns regarding uncontrolled prospecting. Climate change is one of the major issues faced in the 21st century, with predictions of heightened water stress for the Southern African region. This, coupled with increased population growth is putting a massive strain on the water resources currently available, making it vital to better protect and ensure the longevity of our water resources. The Carolina Crisis of 2012 highlighted the importance of protecting our water resources, and how easily they can be contaminated to a point where water is not usable. The Carolina crisis provided researchers with a suitable study site to better understand the role mining operations have in a catchment that has experienced a major pollution incident, and what changes have occurred since. In order to understand coal mining practice in relation to regulatory provisions, this project critically explored the processes involved within the mining sector, from ‘cradle-to-grave’, which is known as the coal mining life cycle. In addition, the composite suite of requirements of all the legislative provisions involved in the industry were investigated and the relationship between coal mining practice and environmental protection was explored. These elements were researched in the Upper Komati River Catchment specifically for catchment X11B, using Cultural Historical Activity Theory (CHAT), which gives a holistic understanding of mining as a human activity system. CHAT also sheds light on the issues, gaps and overlaps currently being experienced in the coal mining sector. The Thesis refers to case studies of where mining issues have caused environmental degradation. A complete mining lifecycle in terms of regulatory provisions was compiled, and major issues were uncovered with current legislation in the mining sector that can contribute to the degradation of water resources in South Africa. An integrated water resource quality management plan is needed in order to streamline conservation mandates, identify and reduce duplication of effort and specify roles and responsibilities of authorities involved with decision making process. A Decision Support System (DSS) has been proposed, which would involve adaptive, participatory and inclusive management.
- Full Text:
- Date Issued: 2018
- Authors: Thomson, Gareth Peter
- Date: 2018
- Subjects: Mineral industries Environmental aspects South Africa Mpumalanga , Acid mine drainage , Mineral industries Safety measures , Watersheds South Africa , South Africa. National Environmental Management Act, 1998 , Water-supply Law and legislation South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63481 , vital:28417
- Description: Mining is one of the most contentious water users. The mining sector has assumed that promises of economic growth and job creation will enable environmental concerns to be bypassed with as little interference as possible. More recently, the reality of legacy issues related to the inappropriate sign-off of mining sites has become increasingly clear, with acid mine drainage (AMD) being a prime example. There are also increasing concerns regarding uncontrolled prospecting. Climate change is one of the major issues faced in the 21st century, with predictions of heightened water stress for the Southern African region. This, coupled with increased population growth is putting a massive strain on the water resources currently available, making it vital to better protect and ensure the longevity of our water resources. The Carolina Crisis of 2012 highlighted the importance of protecting our water resources, and how easily they can be contaminated to a point where water is not usable. The Carolina crisis provided researchers with a suitable study site to better understand the role mining operations have in a catchment that has experienced a major pollution incident, and what changes have occurred since. In order to understand coal mining practice in relation to regulatory provisions, this project critically explored the processes involved within the mining sector, from ‘cradle-to-grave’, which is known as the coal mining life cycle. In addition, the composite suite of requirements of all the legislative provisions involved in the industry were investigated and the relationship between coal mining practice and environmental protection was explored. These elements were researched in the Upper Komati River Catchment specifically for catchment X11B, using Cultural Historical Activity Theory (CHAT), which gives a holistic understanding of mining as a human activity system. CHAT also sheds light on the issues, gaps and overlaps currently being experienced in the coal mining sector. The Thesis refers to case studies of where mining issues have caused environmental degradation. A complete mining lifecycle in terms of regulatory provisions was compiled, and major issues were uncovered with current legislation in the mining sector that can contribute to the degradation of water resources in South Africa. An integrated water resource quality management plan is needed in order to streamline conservation mandates, identify and reduce duplication of effort and specify roles and responsibilities of authorities involved with decision making process. A Decision Support System (DSS) has been proposed, which would involve adaptive, participatory and inclusive management.
- Full Text:
- Date Issued: 2018
A comparison of the performance of selected conceptual models of the rainfall-runoff process in semi-arid catchments near Grahamstown
- Authors: Roberts, Peter J T
- Date: 1979
- Subjects: Runoff , Rainfall , South Africa , Grahamstown
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4798 , http://hdl.handle.net/10962/d1001898
- Description: A comparison of the performance of selected conceptual models of the rainfall-runoff process forms the central theme of this study and the comparison was conducted with three major objectives in mind. The first objective was to develop a conceptual model that could be used by practising hydrologists for the refinement and extension of historical streamflow records. The major requirements of the model were that it should be simple in structure and easy to operate and yet be flexible in terms of complexity of structure and input requirements as well as producing output at a level of accuracy that is competitive with that of the more complex models presently available. A comparison of the performance of the required model with that of other models formed an integral part of the development process. The second objective of the comparative study was to contribute to current knowledge of the criteria used in the selection of a suitable model for a particular application. There are, at present, no reliable guidelines to assist the hydrologist in selecting a suitable model from the wide range of models available and a comparative study would indicate the merits of various forms of model structure. The third objective is associated with the problems that arise when no streamflow data are available for model calibration. One approach is to calibrate the model in a nearby gauged catchment that the hydrologist regards as being 'hydrologically similar' and transferring the model parameter values to the ungauged catchment. Little is known about the feasibility of this parameter transfer process or about the choice of a model for such an application. The third objective was to test the feasibility of the parameter transfer process and to make use of the comparison of model performance to determine the model characteristics that are most suitable for the purpose
- Full Text:
- Date Issued: 1979
- Authors: Roberts, Peter J T
- Date: 1979
- Subjects: Runoff , Rainfall , South Africa , Grahamstown
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4798 , http://hdl.handle.net/10962/d1001898
- Description: A comparison of the performance of selected conceptual models of the rainfall-runoff process forms the central theme of this study and the comparison was conducted with three major objectives in mind. The first objective was to develop a conceptual model that could be used by practising hydrologists for the refinement and extension of historical streamflow records. The major requirements of the model were that it should be simple in structure and easy to operate and yet be flexible in terms of complexity of structure and input requirements as well as producing output at a level of accuracy that is competitive with that of the more complex models presently available. A comparison of the performance of the required model with that of other models formed an integral part of the development process. The second objective of the comparative study was to contribute to current knowledge of the criteria used in the selection of a suitable model for a particular application. There are, at present, no reliable guidelines to assist the hydrologist in selecting a suitable model from the wide range of models available and a comparative study would indicate the merits of various forms of model structure. The third objective is associated with the problems that arise when no streamflow data are available for model calibration. One approach is to calibrate the model in a nearby gauged catchment that the hydrologist regards as being 'hydrologically similar' and transferring the model parameter values to the ungauged catchment. Little is known about the feasibility of this parameter transfer process or about the choice of a model for such an application. The third objective was to test the feasibility of the parameter transfer process and to make use of the comparison of model performance to determine the model characteristics that are most suitable for the purpose
- Full Text:
- Date Issued: 1979
A comparison of the performance of three conceptual mathematical models of the rainfall-runoff process in the Mareetsane Catchment
- Authors: Stickells Peter S
- Date: 1979
- Subjects: Rain and rainfall Mathematical models South Africa Runoff
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4793 , http://hdl.handle.net/10962/d1001893
- Description: The objective of the thesis is to make a critical assessment of the performance of three relatively simple deterministic models of the rainfall-runoff process. The need to evaluate and compare deterministic models arises because of the large number of models which are available in the literature. A number of the available models would appear to be equally suitable for a given situation whereas many models are found to be valid only under the specific range of conditions for which they were developed. Therefore there is a need for guidelines to allow the most judicious selection of a model for a particular set of circumstances. The models used in the study will be tested in a semi-arid catchment to determine their applicability under ephemeral flow conditions
- Full Text:
- Date Issued: 1979
- Authors: Stickells Peter S
- Date: 1979
- Subjects: Rain and rainfall Mathematical models South Africa Runoff
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4793 , http://hdl.handle.net/10962/d1001893
- Description: The objective of the thesis is to make a critical assessment of the performance of three relatively simple deterministic models of the rainfall-runoff process. The need to evaluate and compare deterministic models arises because of the large number of models which are available in the literature. A number of the available models would appear to be equally suitable for a given situation whereas many models are found to be valid only under the specific range of conditions for which they were developed. Therefore there is a need for guidelines to allow the most judicious selection of a model for a particular set of circumstances. The models used in the study will be tested in a semi-arid catchment to determine their applicability under ephemeral flow conditions
- Full Text:
- Date Issued: 1979
A comparison of the reproductive strategies of key species of a prograding dune system in the Mlalazi Nature Reserve, Natal
- Authors: Todd, Colleen Barbara
- Date: 1995
- Subjects: Sand dune plants -- South Africa -- KwaZulu-Natal -- Mlalazi Nature Reserve , Sand dune plants Comparative studies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4231 , http://hdl.handle.net/10962/d1003800 , Sand dune plants -- South Africa -- KwaZulu-Natal -- Mlalazi Nature Reserve , Sand dune plants Comparative studies
- Description: The succession on the dunes of the Mlalazi Nature Reserve represents a classical example of primary succession. The reproductive strategies of eight key species were compared to determine some of the mechanisms affecting the community dynamics, at the population level, in the early stages of succession. There is a temporal separation in the flowering and fruiting phenologies. Passerina rigida, Stipagrostis zeyheri and Imperata cylindrica produced small seeds with a low fruit/seed mass ratio within a short cycle. The seeds are suitable for wind-dispersal. The animal-dispersed species; Eugenia capensis, Mimusops caffra and Scaevola plumieri, produced large fleshy seeds with a high fruit/seed mass ratio within cycles of six months and more. Chrysanthemoides monilifera, also an animal-dispersed species, produced a large quantity of small fleshy seeds throughout the year. The fern, Microsorium scolopendrium produced spores throughout the year. The staggered fruiting and flowering phenology ensures a year-round availability of fruit in the dunefield. The key species formed less than half of the species composition of the soil seed bank. The size and range of the soil seed bank differed between the species. P. rigida and S. plumieri formed a high proportion of the seeds in the soil with a wide distribution along the successional gradient. The other species had low soil seed densities with short distribution ranges, or were not present. P. rigida and S. plumieri are easily dispersed species, whereas the other species may have a more restricted and clumped distribution due to the effect of foragers. A high density of P. rigida and E. capensis seeds were found under the parent trees. Only seeds of P. rigida and S. zeyheri were found in the soil in the open. Seeds of P. rigida, S. zeyheri, E. capensis and M. caffra were found under the canopies of P. rigida, E. capensis and M. caffra. No seeds of C. monilifera and I. cylindrica were found in the soil, possibly due to predation. The period of the study (September 1991 to November 1992) was in a dry or drought cycle with only 56.8% of the mean annual rainfall falling. Seed germination and seedling survival of all the species were affected by these dry, warm climatic conditions. The species had seedling densities of less than 4 seeds/m². The environmental conditions along the successional gradient also had an effect on seed germination and seedling survival. Environmental factors of soil pH, light intensity and surface soil temperatures were higher in the open than under canopy. Soil pH and the understorey cover decreased as the light intensity decreased from under the canopy of P. rigida to M. caffra . Litter cover and plant height increased. E. capensis had measurements intermediate to the two species, but had higher surface soil temperatures and plant height than P. rigida. Seedlings of P. rigida in the open and under the canopy of the parent plants had died by the end of the monitoring period. 50% of the seedlings of S. zeyheri under the canopy of P. rigida and M. caffra died. The mortality rate of the seedlings of E. capensis was lower under M. caffra than under the parent plants. I. cylindrica may be propagated vegetatively. However, the mortality of the propagules was greater under the canopy of E. capensis than under P. rigida. M. caffra only germinated under the canopy of E. capensis with a 100% mortality of the seedlings. M. scolopendrium only produced propagules through vegetative propagation under the canopy of E. capensis and M. caffra. The mortality of the young ferns was less than 50% and less under M. caffra than under E. capensis. No seedlings of C. monilifera or S. plumieri were found. The seed distribution range, seed germination requirements and the effect of the environmental conditions on the germination of the seeds and seedling establishment of the species appear to important factors of the reproductive strategies regulating the size of the species populations along the successional gradient.
- Full Text:
- Date Issued: 1995
- Authors: Todd, Colleen Barbara
- Date: 1995
- Subjects: Sand dune plants -- South Africa -- KwaZulu-Natal -- Mlalazi Nature Reserve , Sand dune plants Comparative studies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4231 , http://hdl.handle.net/10962/d1003800 , Sand dune plants -- South Africa -- KwaZulu-Natal -- Mlalazi Nature Reserve , Sand dune plants Comparative studies
- Description: The succession on the dunes of the Mlalazi Nature Reserve represents a classical example of primary succession. The reproductive strategies of eight key species were compared to determine some of the mechanisms affecting the community dynamics, at the population level, in the early stages of succession. There is a temporal separation in the flowering and fruiting phenologies. Passerina rigida, Stipagrostis zeyheri and Imperata cylindrica produced small seeds with a low fruit/seed mass ratio within a short cycle. The seeds are suitable for wind-dispersal. The animal-dispersed species; Eugenia capensis, Mimusops caffra and Scaevola plumieri, produced large fleshy seeds with a high fruit/seed mass ratio within cycles of six months and more. Chrysanthemoides monilifera, also an animal-dispersed species, produced a large quantity of small fleshy seeds throughout the year. The fern, Microsorium scolopendrium produced spores throughout the year. The staggered fruiting and flowering phenology ensures a year-round availability of fruit in the dunefield. The key species formed less than half of the species composition of the soil seed bank. The size and range of the soil seed bank differed between the species. P. rigida and S. plumieri formed a high proportion of the seeds in the soil with a wide distribution along the successional gradient. The other species had low soil seed densities with short distribution ranges, or were not present. P. rigida and S. plumieri are easily dispersed species, whereas the other species may have a more restricted and clumped distribution due to the effect of foragers. A high density of P. rigida and E. capensis seeds were found under the parent trees. Only seeds of P. rigida and S. zeyheri were found in the soil in the open. Seeds of P. rigida, S. zeyheri, E. capensis and M. caffra were found under the canopies of P. rigida, E. capensis and M. caffra. No seeds of C. monilifera and I. cylindrica were found in the soil, possibly due to predation. The period of the study (September 1991 to November 1992) was in a dry or drought cycle with only 56.8% of the mean annual rainfall falling. Seed germination and seedling survival of all the species were affected by these dry, warm climatic conditions. The species had seedling densities of less than 4 seeds/m². The environmental conditions along the successional gradient also had an effect on seed germination and seedling survival. Environmental factors of soil pH, light intensity and surface soil temperatures were higher in the open than under canopy. Soil pH and the understorey cover decreased as the light intensity decreased from under the canopy of P. rigida to M. caffra . Litter cover and plant height increased. E. capensis had measurements intermediate to the two species, but had higher surface soil temperatures and plant height than P. rigida. Seedlings of P. rigida in the open and under the canopy of the parent plants had died by the end of the monitoring period. 50% of the seedlings of S. zeyheri under the canopy of P. rigida and M. caffra died. The mortality rate of the seedlings of E. capensis was lower under M. caffra than under the parent plants. I. cylindrica may be propagated vegetatively. However, the mortality of the propagules was greater under the canopy of E. capensis than under P. rigida. M. caffra only germinated under the canopy of E. capensis with a 100% mortality of the seedlings. M. scolopendrium only produced propagules through vegetative propagation under the canopy of E. capensis and M. caffra. The mortality of the young ferns was less than 50% and less under M. caffra than under E. capensis. No seedlings of C. monilifera or S. plumieri were found. The seed distribution range, seed germination requirements and the effect of the environmental conditions on the germination of the seeds and seedling establishment of the species appear to important factors of the reproductive strategies regulating the size of the species populations along the successional gradient.
- Full Text:
- Date Issued: 1995
A comparison of the self-esteem of black and white high school pupils
- Authors: Morrow, Brian Robert
- Date: 1988
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193033 , vital:45292
- Description: This study investigated the level of self-esteem of black and white high-school students using the Rosenberg self-esteem scale. One hundred and eighty six subjects were used, 63 of them being white while 118 were black. A validation of the Rosenberg scale for the black sample was attempted using a correlation between the scale score and a rating of the subjects by teachers. The results of the study showed no significant difference between the self-esteem levels, while the validation study failed to confirm the validity of the test for black subjects in South Africa. However, the validation study v/as rejected as inconclusive and the results of the comparison accepted as confirmatory of previous research. An incidental positive finding revealed that white males have higher self-esteem than white females,. The theory and past research of self-esteem comparisons between racial groups is reviewed. The conclusion is reached in this study that the concept of self-esteem has outlasted its usefulness in the field of comparisons between racial groups and research of a qualitative nature .can provide further data for the understanding of differences between racial groups. , Thesis (MA) -- Faculty of Humanities, Psychology, 1988
- Full Text:
- Date Issued: 1988
- Authors: Morrow, Brian Robert
- Date: 1988
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193033 , vital:45292
- Description: This study investigated the level of self-esteem of black and white high-school students using the Rosenberg self-esteem scale. One hundred and eighty six subjects were used, 63 of them being white while 118 were black. A validation of the Rosenberg scale for the black sample was attempted using a correlation between the scale score and a rating of the subjects by teachers. The results of the study showed no significant difference between the self-esteem levels, while the validation study failed to confirm the validity of the test for black subjects in South Africa. However, the validation study v/as rejected as inconclusive and the results of the comparison accepted as confirmatory of previous research. An incidental positive finding revealed that white males have higher self-esteem than white females,. The theory and past research of self-esteem comparisons between racial groups is reviewed. The conclusion is reached in this study that the concept of self-esteem has outlasted its usefulness in the field of comparisons between racial groups and research of a qualitative nature .can provide further data for the understanding of differences between racial groups. , Thesis (MA) -- Faculty of Humanities, Psychology, 1988
- Full Text:
- Date Issued: 1988
A comparison of the views of modern scholars on the origin, date and importance for O.T. study of the Dead Sea Scrolls
- Authors: Sheriffs, Robert J A
- Date: 1954
- Subjects: Dead Sea scrolls
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1273 , http://hdl.handle.net/10962/d1013179
- Description: In the early part of 1948 an announcement was made concerning the discovery of some ancient manuscripts in Palestine; to this discovery sober and distinguished scholars applied adjectives like 'sensational' and 'phenomenal' - words that not commonly applied to the discovery of manuscripts in the world of scholarship.
- Full Text:
- Date Issued: 1954
- Authors: Sheriffs, Robert J A
- Date: 1954
- Subjects: Dead Sea scrolls
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1273 , http://hdl.handle.net/10962/d1013179
- Description: In the early part of 1948 an announcement was made concerning the discovery of some ancient manuscripts in Palestine; to this discovery sober and distinguished scholars applied adjectives like 'sensational' and 'phenomenal' - words that not commonly applied to the discovery of manuscripts in the world of scholarship.
- Full Text:
- Date Issued: 1954
A comparison of the views of South African and American photojournalists to the digital manipulation of news photographs
- Authors: Cass, Taryn May
- Date: 1999
- Subjects: Photojournalists , Photojournalism , Digital media -- Management , Photography -- Digital techniques , Digital media , Photojournalism -- Moral and ethical aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3420 , http://hdl.handle.net/10962/d1002873 , Photojournalists , Photojournalism , Digital media -- Management , Photography -- Digital techniques , Digital media , Photojournalism -- Moral and ethical aspects
- Description: Digital technology has now become pervasive at most publications in South Africa and in America. Pictures are routinely digitised by publications for ease of handling in the layout process, and this makes it relatively easy to alter or manipulate the pictures using computer software programmes. This thesis attempts to gauge the views of South African photojournalists about the digital manipulation of news photographs, and compare these to the views of American photojournalists. It is based on the hypothesis that South African and American photojournalists have different views of what is acceptable manipulation of news photographs, and that their reasons for this will also be different. This thesis also suggests that the manipulation of news photographs is ethically problematic and can damage the credibility of both the photojournalist and the publication in which the photographs appear. The study involves a comparison of the results from a questionnaire given to South African photojournalists and a similar questionnaire given to American photojournalists. The questionnaires were then supplemented by interviews with six South African photojournalists. The thesis then draws conclusions from the responses to the questionnaires and interviews. These conclusions partially support the initial hypothesis, in that there are some differences between the views of South African and American photojournalists, but, on the whole, these are remarkably similar. Photojournalists do seem to find the manipulation of news photographs to be ethically problematic, but they may find the manipulation of other kinds of images (eg fashion or soft news) to be acceptable. South African photographers also find the manipulation of images by other means (eg different lenses or darkroom techniques) to be more acceptable than Americans do. Although the underlying reasons for these views may differ, maintaining the credibility of the photographer and the publication does seem to be the major issue for avoiding digital manipulation. South African photographers seemed to think that if the photographer had done his or her job well, there would be no need for manipulation, and both groups (but especially the Americans) felt that manipulation could often be equated to lying to the reader, and that this might damage their reputation, and that of their publications.
- Full Text:
- Date Issued: 1999
- Authors: Cass, Taryn May
- Date: 1999
- Subjects: Photojournalists , Photojournalism , Digital media -- Management , Photography -- Digital techniques , Digital media , Photojournalism -- Moral and ethical aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3420 , http://hdl.handle.net/10962/d1002873 , Photojournalists , Photojournalism , Digital media -- Management , Photography -- Digital techniques , Digital media , Photojournalism -- Moral and ethical aspects
- Description: Digital technology has now become pervasive at most publications in South Africa and in America. Pictures are routinely digitised by publications for ease of handling in the layout process, and this makes it relatively easy to alter or manipulate the pictures using computer software programmes. This thesis attempts to gauge the views of South African photojournalists about the digital manipulation of news photographs, and compare these to the views of American photojournalists. It is based on the hypothesis that South African and American photojournalists have different views of what is acceptable manipulation of news photographs, and that their reasons for this will also be different. This thesis also suggests that the manipulation of news photographs is ethically problematic and can damage the credibility of both the photojournalist and the publication in which the photographs appear. The study involves a comparison of the results from a questionnaire given to South African photojournalists and a similar questionnaire given to American photojournalists. The questionnaires were then supplemented by interviews with six South African photojournalists. The thesis then draws conclusions from the responses to the questionnaires and interviews. These conclusions partially support the initial hypothesis, in that there are some differences between the views of South African and American photojournalists, but, on the whole, these are remarkably similar. Photojournalists do seem to find the manipulation of news photographs to be ethically problematic, but they may find the manipulation of other kinds of images (eg fashion or soft news) to be acceptable. South African photographers also find the manipulation of images by other means (eg different lenses or darkroom techniques) to be more acceptable than Americans do. Although the underlying reasons for these views may differ, maintaining the credibility of the photographer and the publication does seem to be the major issue for avoiding digital manipulation. South African photographers seemed to think that if the photographer had done his or her job well, there would be no need for manipulation, and both groups (but especially the Americans) felt that manipulation could often be equated to lying to the reader, and that this might damage their reputation, and that of their publications.
- Full Text:
- Date Issued: 1999
A comparison of web-based technologies to serve images from an Oracle9i database
- Authors: Swales, Dylan
- Date: 2004 , 2013-06-18
- Subjects: Active server pages , Microsoft .NET , JavaServer pages , Oracle (Computer file) , Internet searching , Web site development--Computer programs , World Wide Web , Online information services
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4583 , http://hdl.handle.net/10962/d1004380 , Active server pages , Microsoft .NET , JavaServer pages , Oracle (Computer file) , Internet searching , Web site development--Computer programs , World Wide Web , Online information services
- Description: The nature of Internet and Intranet Web applications has changed from a static content-distribution medium into an interactive, dynamic medium, often used to serve multimedia from back-end object-relational databases to Web-enabled clients. Consequently, developers need to make an informed technological choice for developing software that supports a Web-based application for distributing multimedia over networks. This decision is based on several factors. Among the factors are ease of programming, richness of features, scalability, and performance. The research focuses on these key factors when distributing images from an Oracle9i database using Java Servlets, JSP, ASP, and ASP.NET as the server-side development technologies. Prototype applications are developed and tested within each technology: one for single image serving and the other for multiple image serving. A matrix of recommendations is provided to distinguish which technology, or combination of technologies, provides the best performance and development platform for image serving within the studied envirorunent. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2004
- Authors: Swales, Dylan
- Date: 2004 , 2013-06-18
- Subjects: Active server pages , Microsoft .NET , JavaServer pages , Oracle (Computer file) , Internet searching , Web site development--Computer programs , World Wide Web , Online information services
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4583 , http://hdl.handle.net/10962/d1004380 , Active server pages , Microsoft .NET , JavaServer pages , Oracle (Computer file) , Internet searching , Web site development--Computer programs , World Wide Web , Online information services
- Description: The nature of Internet and Intranet Web applications has changed from a static content-distribution medium into an interactive, dynamic medium, often used to serve multimedia from back-end object-relational databases to Web-enabled clients. Consequently, developers need to make an informed technological choice for developing software that supports a Web-based application for distributing multimedia over networks. This decision is based on several factors. Among the factors are ease of programming, richness of features, scalability, and performance. The research focuses on these key factors when distributing images from an Oracle9i database using Java Servlets, JSP, ASP, and ASP.NET as the server-side development technologies. Prototype applications are developed and tested within each technology: one for single image serving and the other for multiple image serving. A matrix of recommendations is provided to distinguish which technology, or combination of technologies, provides the best performance and development platform for image serving within the studied envirorunent. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2004
A comparison of WISC-IV test performance for Afrikaans, English and Xhosa speaking South African grade 7 learners
- Authors: Van der Merwe, Adele
- Date: 2008
- Subjects: Wechsler Intelligence Scale for Children Wechsler Adult Intelligence Scale Intelligence tests -- South Africa Psychological tests -- Cross-cultural studies Educational tests and measurements -- South Africa Educational psychology -- South Africa Language and languages -- Ability testing Educational evaluation -- South Africa Education, Elementary -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3076 , http://hdl.handle.net/10962/d1002585
- Description: his study builds on South African cross-cultural research which demonstrated the importance of careful stratification of multicultural/multilingual normative samples for quality of education in respect of English and African language (predominantly Xhosa) speaking adults and children tested with the WAIS-III and WISC-IV, respectively. The aim of the present study was to produce an expanded set of preliminary comparative norms on the WISC-IV for white and coloured Afrikaans, white English and black Xhosa speaking Grade 7 children, aged 12 to 13 years, stratified for advantaged versus disadvantaged education. The results of this study replicate the findings of the prior South African cross-cultural studies in respect of quality of education, as groups with advantaged private/former Model C schooling outperformed those with disadvantaged former DET or HOR township schooling. Furthermore, a downward continuum of WISC-IV IQ test performance emerged as follows: 1) white English advantaged (high average), 2) white Afrikaans advantaged and black Xhosa advantaged (average), 3) coloured Afrikaans advantaged (below average), 4) black Xhosa disadvantaged (borderline), and 5) coloured Afrikaans disadvantaged (extremely low). The present study has demonstrated that while language and ethnic variables reveal subtle effects on IQ test performance, quality of education has the most significant effect – impacting significantly on verbal performance with this effect replicated in respect of the FSIQ. Therefore caution should be exercised in interpreting test results of individuals from different language/ethnic groups, and in particular those with disadvantaged schooling, as preliminary data suggest that these individuals achieve scores which are 20 – 35 points lower than the UK standardisation.
- Full Text:
- Date Issued: 2008
- Authors: Van der Merwe, Adele
- Date: 2008
- Subjects: Wechsler Intelligence Scale for Children Wechsler Adult Intelligence Scale Intelligence tests -- South Africa Psychological tests -- Cross-cultural studies Educational tests and measurements -- South Africa Educational psychology -- South Africa Language and languages -- Ability testing Educational evaluation -- South Africa Education, Elementary -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3076 , http://hdl.handle.net/10962/d1002585
- Description: his study builds on South African cross-cultural research which demonstrated the importance of careful stratification of multicultural/multilingual normative samples for quality of education in respect of English and African language (predominantly Xhosa) speaking adults and children tested with the WAIS-III and WISC-IV, respectively. The aim of the present study was to produce an expanded set of preliminary comparative norms on the WISC-IV for white and coloured Afrikaans, white English and black Xhosa speaking Grade 7 children, aged 12 to 13 years, stratified for advantaged versus disadvantaged education. The results of this study replicate the findings of the prior South African cross-cultural studies in respect of quality of education, as groups with advantaged private/former Model C schooling outperformed those with disadvantaged former DET or HOR township schooling. Furthermore, a downward continuum of WISC-IV IQ test performance emerged as follows: 1) white English advantaged (high average), 2) white Afrikaans advantaged and black Xhosa advantaged (average), 3) coloured Afrikaans advantaged (below average), 4) black Xhosa disadvantaged (borderline), and 5) coloured Afrikaans disadvantaged (extremely low). The present study has demonstrated that while language and ethnic variables reveal subtle effects on IQ test performance, quality of education has the most significant effect – impacting significantly on verbal performance with this effect replicated in respect of the FSIQ. Therefore caution should be exercised in interpreting test results of individuals from different language/ethnic groups, and in particular those with disadvantaged schooling, as preliminary data suggest that these individuals achieve scores which are 20 – 35 points lower than the UK standardisation.
- Full Text:
- Date Issued: 2008
A compliance framework for IT governance adoption and use by state-owned entities in South Africa
- Authors: Nxozi, Monelo
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/419244 , vital:71628
- Description: Embargoed. Possible release date in early 2025. , Thesis (PhD) -- Faculty of Commerce, Information Systems, 2023
- Full Text:
- Date Issued: 2023-03-31
- Authors: Nxozi, Monelo
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/419244 , vital:71628
- Description: Embargoed. Possible release date in early 2025. , Thesis (PhD) -- Faculty of Commerce, Information Systems, 2023
- Full Text:
- Date Issued: 2023-03-31
A comprehensive approach to scalability assessment of ICTD projects : a case study of ICT4RED
- Authors: Baduza, Gugulethu Qhawekazi
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178435 , vital:42939
- Description: Access restricted until April 2023. , Thesis (PhD) -- Faculty of Commerce, Information Systems, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Baduza, Gugulethu Qhawekazi
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178435 , vital:42939
- Description: Access restricted until April 2023. , Thesis (PhD) -- Faculty of Commerce, Information Systems, 2021
- Full Text:
- Date Issued: 2021-04
A comprehensive guide to conducting compensation surveys to determine competitive adjustments to base salary ranges
- Authors: Snelgar, Robin John
- Date: 1979
- Subjects: Wage surveys , Wages
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2896 , http://hdl.handle.net/10962/d1002060
- Description: The compensation process is a complex network of sub-processes directed toward compensating people for services performed, and motivating them to obtain desired levels of performance. Among the intermediate components of this process are wage and salary payments, the awarding of other cost items such as insurance, vacations, sick leave, etc. (fringe benefits), and the provision of essentially non-cost rewards such as recognition, privileges and symbols of status. However, the broad subject of compensation in terms of cost to the organisation may be examined in two sections, namely, wage and salary administration, and fringe benefit administration. The compensation survey forms an integral part of both administration processes, and thus becomes a necessary and essential device in the determination of the final compensation package to the employee.
- Full Text:
- Date Issued: 1979
- Authors: Snelgar, Robin John
- Date: 1979
- Subjects: Wage surveys , Wages
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2896 , http://hdl.handle.net/10962/d1002060
- Description: The compensation process is a complex network of sub-processes directed toward compensating people for services performed, and motivating them to obtain desired levels of performance. Among the intermediate components of this process are wage and salary payments, the awarding of other cost items such as insurance, vacations, sick leave, etc. (fringe benefits), and the provision of essentially non-cost rewards such as recognition, privileges and symbols of status. However, the broad subject of compensation in terms of cost to the organisation may be examined in two sections, namely, wage and salary administration, and fringe benefit administration. The compensation survey forms an integral part of both administration processes, and thus becomes a necessary and essential device in the determination of the final compensation package to the employee.
- Full Text:
- Date Issued: 1979
A comprehensive review of the taxonomic diversity within the freshwater catfish genus Parauchenoglanis (Siluriformes, Auchenoglanididae)
- Authors: Sithole, Yonela
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/402992 , vital:69912
- Description: Thesis embargoed. To be released early 2026. , Thesis (PhD) -- Faculty of Science, Ichthyology & Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Sithole, Yonela
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/402992 , vital:69912
- Description: Thesis embargoed. To be released early 2026. , Thesis (PhD) -- Faculty of Science, Ichthyology & Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-10-13