Local versus landscape effects of bush encroachment on plant available light, soil moisture, frost occurrence and herbaceous productivity and composition
- Authors: Klopper, Chrisna
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3137 , vital:20376
- Description: Bush encroachment is a global phenomenon and a pressing concern for South Africa rangelands. The expansion and increase in density of Vachellia karroo (hereafter referred to aAcacia karroo) has been documented in the Eastern Cape and KwaZulu Natal in South Africa. This increase in woody species in savannas is often at the expense of grass cover and thus is causing concern about how this will impact agriculture due to possible loss of grazing capacity. To understand the impacts of bush encroachment the effect of trees on their micro-climate and abiotic factors and in turn on the herbaceous layer needs to be examined. The objective of this study was to quantify the effect of Acacia karroo encroachment on the light environment, soil moisture and frost occurrence in the sub-canopy and inter-canopy micro-habitats, and how these changes affected herbaceous player productivity and composition. Another question that is being addressed here is whether, and how, the local tree effects scale up in the landscape and whether prediction can be made based on the effects of individual trees. The study was undertaken on a farm, Endwell, in the Smaldeel, Eastern Cape. At the study site, a semi-arid savanna, Acacia karroo has been encroaching since the 1980’s. The study was conducted at three scales: landscape, stand-wide and local scale. The landscape scale was represented by four areas with 0, 21, 45 and 72% tree canopy cover, the stand-wide scale consisted of transects with varying percentages of tree canopy cover within each of the four levels of encroachment. The local scale was represented by the sub-canopy and inter-canopy environment to test the effect of trees. At the local scale plant available light and soil moisture were lower in the sub-canopy than intercanopy regions, with leaf area index being higher in the sub-canopy. This local negative effect of the tree canopy on light and soil moisture in the sub-canopy did not scale up predictably in the landscape. At the stand-wide scale light in the inter-canopy was reduced as shading increased. Frost was excluded from under the canopies and frost incidence decreased at higher tree cover. Grass productivity was reduced in the sub-canopy, possibly due to lower light and soil moisture. Overall biomass increased from the low to medium level of encroachment but lowest at the high level of encroachment. Grass composition and cover was only slightly affected by tree canopies cover and C4 grass species were still present in the sub-canopy and at lower light environments. At the levels of Acacia karroo encroachment encountered at this study site, it seems unlikely that palatable or desirable C4 would be excluded from the system and that a shift from C4 to shade-tolerant species would occur. This is due to tree canopies at the site not reducing light to such anextent that they would outcompete grasses, and likely the very low grazing pressure at thesesites. Herbaceous biomass at these sites were still sufficient to carry a fire in the inter-canopyregion and sufficient grazing for herbivores. In the sub-canopy region fires will be excluded thus with higher the portion of sub-canopy areas increasing at the high levels of encroachment they may interrupt fire spread. Thus it was concluded that Acacia karroo encroachment up to 45% tree cover is currently not creating negative feedback on herbivory, but low stocking rates appear to be key to maintain this.
- Full Text:
- Authors: Klopper, Chrisna
- Date: 2016
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3137 , vital:20376
- Description: Bush encroachment is a global phenomenon and a pressing concern for South Africa rangelands. The expansion and increase in density of Vachellia karroo (hereafter referred to aAcacia karroo) has been documented in the Eastern Cape and KwaZulu Natal in South Africa. This increase in woody species in savannas is often at the expense of grass cover and thus is causing concern about how this will impact agriculture due to possible loss of grazing capacity. To understand the impacts of bush encroachment the effect of trees on their micro-climate and abiotic factors and in turn on the herbaceous layer needs to be examined. The objective of this study was to quantify the effect of Acacia karroo encroachment on the light environment, soil moisture and frost occurrence in the sub-canopy and inter-canopy micro-habitats, and how these changes affected herbaceous player productivity and composition. Another question that is being addressed here is whether, and how, the local tree effects scale up in the landscape and whether prediction can be made based on the effects of individual trees. The study was undertaken on a farm, Endwell, in the Smaldeel, Eastern Cape. At the study site, a semi-arid savanna, Acacia karroo has been encroaching since the 1980’s. The study was conducted at three scales: landscape, stand-wide and local scale. The landscape scale was represented by four areas with 0, 21, 45 and 72% tree canopy cover, the stand-wide scale consisted of transects with varying percentages of tree canopy cover within each of the four levels of encroachment. The local scale was represented by the sub-canopy and inter-canopy environment to test the effect of trees. At the local scale plant available light and soil moisture were lower in the sub-canopy than intercanopy regions, with leaf area index being higher in the sub-canopy. This local negative effect of the tree canopy on light and soil moisture in the sub-canopy did not scale up predictably in the landscape. At the stand-wide scale light in the inter-canopy was reduced as shading increased. Frost was excluded from under the canopies and frost incidence decreased at higher tree cover. Grass productivity was reduced in the sub-canopy, possibly due to lower light and soil moisture. Overall biomass increased from the low to medium level of encroachment but lowest at the high level of encroachment. Grass composition and cover was only slightly affected by tree canopies cover and C4 grass species were still present in the sub-canopy and at lower light environments. At the levels of Acacia karroo encroachment encountered at this study site, it seems unlikely that palatable or desirable C4 would be excluded from the system and that a shift from C4 to shade-tolerant species would occur. This is due to tree canopies at the site not reducing light to such anextent that they would outcompete grasses, and likely the very low grazing pressure at thesesites. Herbaceous biomass at these sites were still sufficient to carry a fire in the inter-canopyregion and sufficient grazing for herbivores. In the sub-canopy region fires will be excluded thus with higher the portion of sub-canopy areas increasing at the high levels of encroachment they may interrupt fire spread. Thus it was concluded that Acacia karroo encroachment up to 45% tree cover is currently not creating negative feedback on herbivory, but low stocking rates appear to be key to maintain this.
- Full Text:
Feeding dynamics and distribution of the hyperiid amphipod, Themisto gaudichaudii (Guérin, 1828) in the polar frontal zone, Southern Ocean
- Authors: Lange, Louise
- Date: 2006
- Subjects: Themisto gaudichaudii -- Antarctic Ocean , Hyperiidae -- Antarctic Ocean , Zooplankton -- Antarctic Ocean
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5696 , http://hdl.handle.net/10962/d1005382 , Themisto gaudichaudii -- Antarctic Ocean , Hyperiidae -- Antarctic Ocean , Zooplankton -- Antarctic Ocean
- Description: The population structure and feeding dynamics of the hyperiid amphipod, Themisto gaudichaudii, was investigated during two cruises of the South African National Antarctic Programme conducted in the Indian sector of the Polar Frontal Zone during austral autumn (April) 2004 and 2005. During the 2004 cruise the frontal features that delimit the PFZ converged to form a single distinctive feature. In 2005, the research cruise was conducted in the vicinity of a cold-core eddy which was spawned from the Antarctic Polar Front. Total mesozooplankton abundance and biomass during the 2004 study ranged from 55.19 to 860.57 ind. m⁻³, and from 2.60 to 38.42 mg dwt m⁻³, respectively. In 2005 the abundance and biomass ranged from 23.1 to 2160.64 ind. m⁻³, and from 0.76 to 35.16 mg dwt m⁻³, respectively. The mesozooplankton community was numerically dominated by copepods, pteropods, and ostracods during both surveys. The abundance and biomass of Themisto gaudichaudii in the region of investigation was < 0.2 ind. m⁻³ (range 0.01 to 0.15 ind. m⁻³) and < 0.06 mg dwt m⁻³ (range 0.02 to 0.06 mg dwt m⁻³) during 2004, while in 2005 the abundance and biomass of the amphipod ranged from < 0.01 to 0.2 ind. m⁻³ and < 0.01 to 0.04 mg dwt m⁻³, respectively. These values correspond to < 1% of the total mesozooplankton abundance and biomass during both surveys. T. gaudichaudii exhibited no significant spatial patterns in abundance, biomass and total length during both 2004 and 2005 (p > 0.05 in all cases). A key feature of the two investigations was the virtual absence of juveniles (total length < 15 mm) among the amphipod population, supporting the suggestion that they exhibit strong seasonal patterns in reproduction. Gut content analysis during both years indicated that for both the male and female amphipods’, copepods were the most prevalent prey species found in stomachs, followed by chaetognaths and pteropods. Results of electivity studies indicate that T. gaudichaudii is an opportunistic predator, generally feeding on the most abundant mesozooplankton prey. Results of in vitro incubations indicated that the total daily feeding rate of T. gaudichaudii during 2004 ranged from 11.45 to 20.90 ind. m⁻³ d⁻¹, which corresponds to between 0.12 and 1.64% of the total mesozooplankton standing stock. In 2005, the feeding rate ranged between 0.1 and 1.73% of the total mesozooplankton standing stock. The low predation impact of T. gaudichaudii during this study can be related to their low abundances and high interannual variability throughout the region of investigation.
- Full Text:
- Authors: Lange, Louise
- Date: 2006
- Subjects: Themisto gaudichaudii -- Antarctic Ocean , Hyperiidae -- Antarctic Ocean , Zooplankton -- Antarctic Ocean
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5696 , http://hdl.handle.net/10962/d1005382 , Themisto gaudichaudii -- Antarctic Ocean , Hyperiidae -- Antarctic Ocean , Zooplankton -- Antarctic Ocean
- Description: The population structure and feeding dynamics of the hyperiid amphipod, Themisto gaudichaudii, was investigated during two cruises of the South African National Antarctic Programme conducted in the Indian sector of the Polar Frontal Zone during austral autumn (April) 2004 and 2005. During the 2004 cruise the frontal features that delimit the PFZ converged to form a single distinctive feature. In 2005, the research cruise was conducted in the vicinity of a cold-core eddy which was spawned from the Antarctic Polar Front. Total mesozooplankton abundance and biomass during the 2004 study ranged from 55.19 to 860.57 ind. m⁻³, and from 2.60 to 38.42 mg dwt m⁻³, respectively. In 2005 the abundance and biomass ranged from 23.1 to 2160.64 ind. m⁻³, and from 0.76 to 35.16 mg dwt m⁻³, respectively. The mesozooplankton community was numerically dominated by copepods, pteropods, and ostracods during both surveys. The abundance and biomass of Themisto gaudichaudii in the region of investigation was < 0.2 ind. m⁻³ (range 0.01 to 0.15 ind. m⁻³) and < 0.06 mg dwt m⁻³ (range 0.02 to 0.06 mg dwt m⁻³) during 2004, while in 2005 the abundance and biomass of the amphipod ranged from < 0.01 to 0.2 ind. m⁻³ and < 0.01 to 0.04 mg dwt m⁻³, respectively. These values correspond to < 1% of the total mesozooplankton abundance and biomass during both surveys. T. gaudichaudii exhibited no significant spatial patterns in abundance, biomass and total length during both 2004 and 2005 (p > 0.05 in all cases). A key feature of the two investigations was the virtual absence of juveniles (total length < 15 mm) among the amphipod population, supporting the suggestion that they exhibit strong seasonal patterns in reproduction. Gut content analysis during both years indicated that for both the male and female amphipods’, copepods were the most prevalent prey species found in stomachs, followed by chaetognaths and pteropods. Results of electivity studies indicate that T. gaudichaudii is an opportunistic predator, generally feeding on the most abundant mesozooplankton prey. Results of in vitro incubations indicated that the total daily feeding rate of T. gaudichaudii during 2004 ranged from 11.45 to 20.90 ind. m⁻³ d⁻¹, which corresponds to between 0.12 and 1.64% of the total mesozooplankton standing stock. In 2005, the feeding rate ranged between 0.1 and 1.73% of the total mesozooplankton standing stock. The low predation impact of T. gaudichaudii during this study can be related to their low abundances and high interannual variability throughout the region of investigation.
- Full Text:
Classical and quantum picture of the interior of two-dimensional black holes
- Authors: Shawa, Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3629 , vital:20531
- Description: A quantum-mechanical description of black holes would represent the final step in our understanding of the nature of space-time. However, any progress towards that end is usually foiled by persistent space-time singularities that exist at the center of black holes. From the four-dimensional point of view, black holes seem to resist quantization. Under highly symmetric conditions, all higher-dimensional black holes are two-dimensional. Unlike their higher-dimensional counterparts, two dimensional black holes may not resist quantization. A non-trivial description of gravity in two dimensions is not possible using Einstein’s theory of gravity alone. However, we may still arrive at a consistent description of gravity by introducing a scalar field known as the dilaton. In this thesis, we study both the classical and quantum aspects of the interior of two-dimensional black holes using a generalized dilaton-gravity theory. Classically, we will find that the interior of most two-dimensional black holes is not much different from that of four-dimensional black holes. But by introducing quantized matter into the theory, the fluctuations in space-time will give a different picture of the structure of interior of black holes. Using a low-energy effective field theory, we will show that it is indeed possible to identify quantum modes in the interior of black holes and perform quantum-mechanical calculations near the singularity.
- Full Text:
- Authors: Shawa, Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3629 , vital:20531
- Description: A quantum-mechanical description of black holes would represent the final step in our understanding of the nature of space-time. However, any progress towards that end is usually foiled by persistent space-time singularities that exist at the center of black holes. From the four-dimensional point of view, black holes seem to resist quantization. Under highly symmetric conditions, all higher-dimensional black holes are two-dimensional. Unlike their higher-dimensional counterparts, two dimensional black holes may not resist quantization. A non-trivial description of gravity in two dimensions is not possible using Einstein’s theory of gravity alone. However, we may still arrive at a consistent description of gravity by introducing a scalar field known as the dilaton. In this thesis, we study both the classical and quantum aspects of the interior of two-dimensional black holes using a generalized dilaton-gravity theory. Classically, we will find that the interior of most two-dimensional black holes is not much different from that of four-dimensional black holes. But by introducing quantized matter into the theory, the fluctuations in space-time will give a different picture of the structure of interior of black holes. Using a low-energy effective field theory, we will show that it is indeed possible to identify quantum modes in the interior of black holes and perform quantum-mechanical calculations near the singularity.
- Full Text:
Photofluorescence decay times of organic phosphors
- Authors: Hamilton, T D S
- Date: 1957
- Subjects: Fluorescence , Phosphorescence
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5525 , http://hdl.handle.net/10962/d1012136 , Fluorescence , Phosphorescence
- Description: The absorption and emission of energy is a fundamental property of any atomic system.When the emission occurs in the visible or near visible region the phenomenon is usually referred to as luminescence or fluorescence. This must be distinguished from thermal radiation as it does not follow Kirchoff's law.
- Full Text:
- Authors: Hamilton, T D S
- Date: 1957
- Subjects: Fluorescence , Phosphorescence
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5525 , http://hdl.handle.net/10962/d1012136 , Fluorescence , Phosphorescence
- Description: The absorption and emission of energy is a fundamental property of any atomic system.When the emission occurs in the visible or near visible region the phenomenon is usually referred to as luminescence or fluorescence. This must be distinguished from thermal radiation as it does not follow Kirchoff's law.
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South African International Relations (Ir) and the China-Africa relationship: a critical reflection
- Authors: Walker, Timothy Charles
- Date: 2014
- Subjects: South Africa -- Relations -- China , China -- Relations -- South Africa , International relations -- Philosophy , Critical theory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2885 , http://hdl.handle.net/10962/d1015518
- Description: South African International Relations (IR) is a prominent source of China-Africa research and analysis, producing reports, journal articles and books that seek to illuminate the emerging relationship between China and Africa. It plays an important role in the framing of the relationship, as well as how it is perceived outside of the discipline. However, critical concerns have been raised about the context within which South African IR operates. It is therefore important that IR research, including its assumptions, dominant concepts, professed values and aspirations to studying the China-Africa relationship, be critically examined. The aim of this thesis is to contribute to critical thinking in South African IR by opening up for future discussion the new directions and possibilities for China-Africa IR. Utilising a critique located in Critical International Relations Theory (CIRT), this thesis critically reflects upon both the context of South African IR’s China-Africa research and the perspectives it has produced. The thesis argues that in spite of many descriptive and empirical studies, China- Africa research is theoretically underdeveloped in South African IR. Further, it argues that theoretical work is marginalised despite the fact that both historical and contemporary research relies on concepts drawn from IR theory. South African IR’s focus on policy relevance is advanced as a reason for the prevalence of theoretical underdevelopment. This thesis concludes by reviewing arguments for the improved use of IR theory in China-Africa IR, which will lead to a better understanding of this important relationship.
- Full Text:
- Authors: Walker, Timothy Charles
- Date: 2014
- Subjects: South Africa -- Relations -- China , China -- Relations -- South Africa , International relations -- Philosophy , Critical theory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2885 , http://hdl.handle.net/10962/d1015518
- Description: South African International Relations (IR) is a prominent source of China-Africa research and analysis, producing reports, journal articles and books that seek to illuminate the emerging relationship between China and Africa. It plays an important role in the framing of the relationship, as well as how it is perceived outside of the discipline. However, critical concerns have been raised about the context within which South African IR operates. It is therefore important that IR research, including its assumptions, dominant concepts, professed values and aspirations to studying the China-Africa relationship, be critically examined. The aim of this thesis is to contribute to critical thinking in South African IR by opening up for future discussion the new directions and possibilities for China-Africa IR. Utilising a critique located in Critical International Relations Theory (CIRT), this thesis critically reflects upon both the context of South African IR’s China-Africa research and the perspectives it has produced. The thesis argues that in spite of many descriptive and empirical studies, China- Africa research is theoretically underdeveloped in South African IR. Further, it argues that theoretical work is marginalised despite the fact that both historical and contemporary research relies on concepts drawn from IR theory. South African IR’s focus on policy relevance is advanced as a reason for the prevalence of theoretical underdevelopment. This thesis concludes by reviewing arguments for the improved use of IR theory in China-Africa IR, which will lead to a better understanding of this important relationship.
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In a town called Harmony
- Authors: Tsibolane, Pitso
- Date: 2015
- Subjects: South African fiction (English) -- 21st century , Creative writing (Higher education) , South African fiction (English) -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5995 , http://hdl.handle.net/10962/d1017779
- Description: A novella of crime and suspense set in the townships surrounding the mining town of Welkom Two friends, both ex-miners, start a welding business only to see it fail because of interference by corrupt officials To make ends meet, they are drawn into the world of illegal gold-mining, working with criminals who employ ‘zama-zamas’: desperate foreign nationals who are prepared to live and work in the abandoned mine tunnels underground The friends make money, but the dark practices of illegal mining put a strain on their relationship, their values, and their family ties.
- Full Text:
- Authors: Tsibolane, Pitso
- Date: 2015
- Subjects: South African fiction (English) -- 21st century , Creative writing (Higher education) , South African fiction (English) -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5995 , http://hdl.handle.net/10962/d1017779
- Description: A novella of crime and suspense set in the townships surrounding the mining town of Welkom Two friends, both ex-miners, start a welding business only to see it fail because of interference by corrupt officials To make ends meet, they are drawn into the world of illegal gold-mining, working with criminals who employ ‘zama-zamas’: desperate foreign nationals who are prepared to live and work in the abandoned mine tunnels underground The friends make money, but the dark practices of illegal mining put a strain on their relationship, their values, and their family ties.
- Full Text:
Some aspects of concept acquisition in history
- Authors: Macrae, Michael John
- Date: 1987
- Subjects: History -- Study and teaching -- South Africa , History -- Study and teaching -- Testing , History -- Study and teaching -- Methodology
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1367 , http://hdl.handle.net/10962/d1001433
- Description: There is concern that school history is often purposeless, taught by chalk and talk and textbook methods, giving thin and unassimilated information. At a time when subjects are under increasing scrutiny and pressure to justify their existence as relevant in the school curriculum, many of the defects inherent in the 'traditional' approach to history have made it difficult to present a forceful and valid argument for its continued inclusion as a school subject.This has led to the adoption of new approaches which are designed to get pupils more actively involved in their learning. One such approach was adopted by the Schools Council 13-16 project in Britain. It laid emphasis on the methodology of the subject and identified five ways in which history could prove to be a useful and necessary subject for adolescents to study. These were: as a means of acquiring and developing such cognitive skills as those of analysis, synthesis and judgement; as a source of leisure interests; as a vehicle for analysing the contemporary world and pupils' place in it; as a means for developing understanding of the forces underlying social change and evolutioni and, finally, as an avenue to self-knowledge and awareness of what it means to be human (Introduction, p. ii)
- Full Text:
- Authors: Macrae, Michael John
- Date: 1987
- Subjects: History -- Study and teaching -- South Africa , History -- Study and teaching -- Testing , History -- Study and teaching -- Methodology
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1367 , http://hdl.handle.net/10962/d1001433
- Description: There is concern that school history is often purposeless, taught by chalk and talk and textbook methods, giving thin and unassimilated information. At a time when subjects are under increasing scrutiny and pressure to justify their existence as relevant in the school curriculum, many of the defects inherent in the 'traditional' approach to history have made it difficult to present a forceful and valid argument for its continued inclusion as a school subject.This has led to the adoption of new approaches which are designed to get pupils more actively involved in their learning. One such approach was adopted by the Schools Council 13-16 project in Britain. It laid emphasis on the methodology of the subject and identified five ways in which history could prove to be a useful and necessary subject for adolescents to study. These were: as a means of acquiring and developing such cognitive skills as those of analysis, synthesis and judgement; as a source of leisure interests; as a vehicle for analysing the contemporary world and pupils' place in it; as a means for developing understanding of the forces underlying social change and evolutioni and, finally, as an avenue to self-knowledge and awareness of what it means to be human (Introduction, p. ii)
- Full Text:
The tectonic evolution of the Cape Fold Belt: constraints from fluid inclusion characteristics in syntectonic quartz veins
- Authors: Proctor, Briony
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/8019 , vital:21335
- Description: Syn-tectonic quartz veins formed along faults, folds and tension gashes in rocks of the Cape Supergroup (CSG) of the central Cape Fold Belt (CFB) comprise mainly hydrous saline fluids. These veins may also contain CO₂ Syn-tectonic quartz veins formed along faults, folds and tension gashes in rocks of the Cape Supergroup CO₂ , or CH4 and CO₂, or neither CO₂ nor CH4. The majority of inclusions are two-phase and fluid rich, and the most common fluid composition is H2O-NaCl. The final melting temperature, and therefore salinity, differs very little across different structures (fluids in all structures show maximum salinities between 2.5 and 6 wt% NaCl equivalent). Thrusts, reverse faults, strike- and oblique-slip faults, and folds all have similar homogenization temperatures (Th). Primary H2O-NaCl inclusions show Th between ~130 and 200 °C, and H2O-NaCl-CO₂ inclusions have slightly higher Th, between ~140 and 240 °C. Secondary inclusions in all structures have a similar Th range to primary inclusions, but have a lower maximum Th (~130-180 °C). Inclusions containing CH4 have the highest Th (~210 - 300 °C). Microthermobarometry indicates that fluids associated with contractional structures, such as thrust faults or folds, from the Ordovician lower Table Mountain Group (TMG) show lower greenschist facies trapping conditions (~170-175 MPa and ~240-300 °C). These veins also show a plastic deformation overprint (recrystallization of quartz and foam textures), at temperatures higher than the trapping conditions (~ ≥300 °C), indicating that temperatures increased subsequent to hydraulic fracturing, quartz precipitation and thrust slip. These structures formed on a prograde path, at approximately 335 Ma, at a time when the overlying CSG rock column was approximately 6800 m thick. This event pre-dated the thermal peak of the Cape Orogeny at ~276-261 Ma by ~60 million years. Further up in the stratigraphy of the CFB, in the Devonian upper Bokkeveld Group, fluid inclusions in quartz veins associated with a thrust fault show similar trapping pressure (~200 MPa) to the structures in the lower CFB. At 335 Ma, the stratigraphic overburden on this sample locality would not have been sufficiently thick to exert the calculated pressure. This fault may have formed at a later time. The observed pressure of ~200 MPa may have been created either by the higher Bokkeveld Group, the entire Witteberg Group, and further CSG rocks that were eroded prior to the deposition of the Permo-Triassic Karoo Supergroup, or by tectonic thickening of the CSG by prograde thrusting. Still further up in the CSG, fluids from a fold sample from the Witteberg Group record quartz precipitation at lower greenschist facies conditions and subsequent plastic deformation during folding. The formation of this fold postdates the thrusting in the lower TMG, and may correlate in time with deformation during the thermal peak in Middle Permian time (~276-261 Ma).
- Full Text:
- Authors: Proctor, Briony
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/8019 , vital:21335
- Description: Syn-tectonic quartz veins formed along faults, folds and tension gashes in rocks of the Cape Supergroup (CSG) of the central Cape Fold Belt (CFB) comprise mainly hydrous saline fluids. These veins may also contain CO₂ Syn-tectonic quartz veins formed along faults, folds and tension gashes in rocks of the Cape Supergroup CO₂ , or CH4 and CO₂, or neither CO₂ nor CH4. The majority of inclusions are two-phase and fluid rich, and the most common fluid composition is H2O-NaCl. The final melting temperature, and therefore salinity, differs very little across different structures (fluids in all structures show maximum salinities between 2.5 and 6 wt% NaCl equivalent). Thrusts, reverse faults, strike- and oblique-slip faults, and folds all have similar homogenization temperatures (Th). Primary H2O-NaCl inclusions show Th between ~130 and 200 °C, and H2O-NaCl-CO₂ inclusions have slightly higher Th, between ~140 and 240 °C. Secondary inclusions in all structures have a similar Th range to primary inclusions, but have a lower maximum Th (~130-180 °C). Inclusions containing CH4 have the highest Th (~210 - 300 °C). Microthermobarometry indicates that fluids associated with contractional structures, such as thrust faults or folds, from the Ordovician lower Table Mountain Group (TMG) show lower greenschist facies trapping conditions (~170-175 MPa and ~240-300 °C). These veins also show a plastic deformation overprint (recrystallization of quartz and foam textures), at temperatures higher than the trapping conditions (~ ≥300 °C), indicating that temperatures increased subsequent to hydraulic fracturing, quartz precipitation and thrust slip. These structures formed on a prograde path, at approximately 335 Ma, at a time when the overlying CSG rock column was approximately 6800 m thick. This event pre-dated the thermal peak of the Cape Orogeny at ~276-261 Ma by ~60 million years. Further up in the stratigraphy of the CFB, in the Devonian upper Bokkeveld Group, fluid inclusions in quartz veins associated with a thrust fault show similar trapping pressure (~200 MPa) to the structures in the lower CFB. At 335 Ma, the stratigraphic overburden on this sample locality would not have been sufficiently thick to exert the calculated pressure. This fault may have formed at a later time. The observed pressure of ~200 MPa may have been created either by the higher Bokkeveld Group, the entire Witteberg Group, and further CSG rocks that were eroded prior to the deposition of the Permo-Triassic Karoo Supergroup, or by tectonic thickening of the CSG by prograde thrusting. Still further up in the CSG, fluids from a fold sample from the Witteberg Group record quartz precipitation at lower greenschist facies conditions and subsequent plastic deformation during folding. The formation of this fold postdates the thrusting in the lower TMG, and may correlate in time with deformation during the thermal peak in Middle Permian time (~276-261 Ma).
- Full Text:
The lived experience of the post-termination period of long-term psychotherapy
- Steenkamp, Jeanette Gwendoline
- Authors: Steenkamp, Jeanette Gwendoline
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3276 , http://hdl.handle.net/10962/d1021272
- Description: This study aimed to gain insight and understanding into adult clients’ personal lived experiences of the post-termination period of long-term psychotherapy. International research which examines the post-termination phase of psychotherapy has found that this particular lived experience can have both positive and negative consequences for clients’ psychosocial wellbeing. Few recent studies focusing on adult clients’ personal experiences of the post-termination phase could be located and none of these studies were conducted in a non-Western context. The study’s aim was to address this gap in the existing literature by using interpretative-phenomenological analysis (IPA) to explore the lived experience of the post-termination period of long-term psychotherapy for two South African adult clients. Data were collected via individual in-depth semi-structured interviews. Analysis of the data yielded the following themes: Therapy remembered as amazing, but hard work, Vivid memories of therapy retained post-termination, Seeing the therapist differently, Keeping the therapist alive, Being different after therapy, “I started losing all my ground I had gained”, and Resuming the external journey. These findings corroborated and expanded upon existing research in the area.
- Full Text:
- Authors: Steenkamp, Jeanette Gwendoline
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3276 , http://hdl.handle.net/10962/d1021272
- Description: This study aimed to gain insight and understanding into adult clients’ personal lived experiences of the post-termination period of long-term psychotherapy. International research which examines the post-termination phase of psychotherapy has found that this particular lived experience can have both positive and negative consequences for clients’ psychosocial wellbeing. Few recent studies focusing on adult clients’ personal experiences of the post-termination phase could be located and none of these studies were conducted in a non-Western context. The study’s aim was to address this gap in the existing literature by using interpretative-phenomenological analysis (IPA) to explore the lived experience of the post-termination period of long-term psychotherapy for two South African adult clients. Data were collected via individual in-depth semi-structured interviews. Analysis of the data yielded the following themes: Therapy remembered as amazing, but hard work, Vivid memories of therapy retained post-termination, Seeing the therapist differently, Keeping the therapist alive, Being different after therapy, “I started losing all my ground I had gained”, and Resuming the external journey. These findings corroborated and expanded upon existing research in the area.
- Full Text:
The effect of the feminist movement on painting and sculpture in Europe and America after 1945
- Authors: Brooks, Jennifer
- Date: 1983
- Subjects: Painting, American -- 20th century Painting, European -- 20th century Sculpture, European -- 20th century Sculpture, American -- 20th century Feminism and art -- United States Feminism and art -- Europe
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2459 , http://hdl.handle.net/10962/d1007675
- Description: My investigation of women artists and their status in society today as a result of the feminist movement, revealed issues which, I felt, were multifaceted. This necessitated an exploration of many aspects in order to arrive at a fairly satisfactory conclusion as to whether the revolt and the aggression on the part of the feminists had borne any fruit, either generally in everyday life, or artistically. It has proved most stimulating and informative. I think that the need to assess oneself as a woman, working within a male-dominated creative environment is a very necessary process and one which has been most beneficial to me. The subsequent research revealed that a radical, thematic change had occured within the feminist movement at the start of the Eighties; a fact of which, till recently, I was largely unaware. What I discovered was that the militant, feminist approach of the Sixties and Seventies had given way to a more realistic involvement brought on partly by the economic recession and the effects as well of earlier feminist movements, leading to a relaxation on the part of the younger generation. The Violence had faded. Hard times curbed the excesses of the movement and took it along the road to practicality. Dovetailed to this and seeming to run concurrently was the phenomenon of the demise of the Modern Art Movement. These changes described were not only artistic and feminist, but cut right across the board. involving all facets of life. To take one as an example. the political with conservatism reinstating itself in America not merely as an alternative but as a worthwhile direction in itself. Other issues included the sociological, historical, biological, and cultural; all closely interwoven and therefore requiring some generalisations at times. Previous to becoming involved with my topic, I had been reacting to pre-conceived ideas laid on me as a student in the Sixties and Seventies - a militant, aggressive approach acquired as a protective shield, to deal with the masculine environment which denigrated in varying degrees mine and fellow female artists work, sometimes overtly, sometimes subconsciously. This discrimination, is usually denied as ever having existed by the men involved. It shows a lack of awareness of what, we, as female art students, were subjected to. This is one of the main reasons why I undertook this subject; partly out of interest and perhaps partly as some sort of catharsis.
- Full Text:
- Authors: Brooks, Jennifer
- Date: 1983
- Subjects: Painting, American -- 20th century Painting, European -- 20th century Sculpture, European -- 20th century Sculpture, American -- 20th century Feminism and art -- United States Feminism and art -- Europe
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2459 , http://hdl.handle.net/10962/d1007675
- Description: My investigation of women artists and their status in society today as a result of the feminist movement, revealed issues which, I felt, were multifaceted. This necessitated an exploration of many aspects in order to arrive at a fairly satisfactory conclusion as to whether the revolt and the aggression on the part of the feminists had borne any fruit, either generally in everyday life, or artistically. It has proved most stimulating and informative. I think that the need to assess oneself as a woman, working within a male-dominated creative environment is a very necessary process and one which has been most beneficial to me. The subsequent research revealed that a radical, thematic change had occured within the feminist movement at the start of the Eighties; a fact of which, till recently, I was largely unaware. What I discovered was that the militant, feminist approach of the Sixties and Seventies had given way to a more realistic involvement brought on partly by the economic recession and the effects as well of earlier feminist movements, leading to a relaxation on the part of the younger generation. The Violence had faded. Hard times curbed the excesses of the movement and took it along the road to practicality. Dovetailed to this and seeming to run concurrently was the phenomenon of the demise of the Modern Art Movement. These changes described were not only artistic and feminist, but cut right across the board. involving all facets of life. To take one as an example. the political with conservatism reinstating itself in America not merely as an alternative but as a worthwhile direction in itself. Other issues included the sociological, historical, biological, and cultural; all closely interwoven and therefore requiring some generalisations at times. Previous to becoming involved with my topic, I had been reacting to pre-conceived ideas laid on me as a student in the Sixties and Seventies - a militant, aggressive approach acquired as a protective shield, to deal with the masculine environment which denigrated in varying degrees mine and fellow female artists work, sometimes overtly, sometimes subconsciously. This discrimination, is usually denied as ever having existed by the men involved. It shows a lack of awareness of what, we, as female art students, were subjected to. This is one of the main reasons why I undertook this subject; partly out of interest and perhaps partly as some sort of catharsis.
- Full Text:
An analysis of the income tax consequences resulting from implementing the Income Tax Bill (2012) in Zimbabwe
- Authors: Kanyenze, Rumbidzai
- Date: 2015
- Subjects: Income tax deductions -- Zimbabwe , Income tax -- Law and legislation -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:914 , http://hdl.handle.net/10962/d1017536
- Description: The Income Tax Bill (2012) proposes certain changes to the existing Income Tax Act that will impact on the method used to determine the taxable income of a taxpayer in Zimbabwe. Therefore, it is important to understand the tax consequences the Income Tax Bill creates for the taxpayer. The research aimed to elaborate on and explain the tax consequences that will arise as a result of applying the Income Tax Bill in Zimbabwe. The research was based on a qualitative method which involved the analysis and the interpretation of extracts from legislation and articles written on the proposed changes. The current “gross income” of a taxpayer consists of amounts earned from a source within or deemed to be from within Zimbabwe The proposed changes to the Act will change the tax system to a residence-based system, where resident taxpayers are taxed on amounts earned from all sources. Therefore, the driving factor which determines the taxability of an amount will become the taxpayer’s residency. Clause 2 of the proposed Act provides that income earned by a taxpayer should be separated into employment income, business income, property income and other specified income. This will make it unnecessary to determine the nature of an amount because capital amounts will be subject to income tax. The current Act provides for the deduction of expenditure incurred for the purpose of trade or in the production of income. Section 31(1)(a) of the proposed Act will restrict permissible deductions to expenditure incurred in the production of income. Consequently, expenditure not incurred for the purpose of earning income will no longer be deductible when the Income Tax Bill is implemented. The proposed Income Tax Act will increase the taxable income of a taxpayer as it makes amounts that are not currently subject to tax taxable, whilst restricting the deductions claimable.
- Full Text:
- Authors: Kanyenze, Rumbidzai
- Date: 2015
- Subjects: Income tax deductions -- Zimbabwe , Income tax -- Law and legislation -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:914 , http://hdl.handle.net/10962/d1017536
- Description: The Income Tax Bill (2012) proposes certain changes to the existing Income Tax Act that will impact on the method used to determine the taxable income of a taxpayer in Zimbabwe. Therefore, it is important to understand the tax consequences the Income Tax Bill creates for the taxpayer. The research aimed to elaborate on and explain the tax consequences that will arise as a result of applying the Income Tax Bill in Zimbabwe. The research was based on a qualitative method which involved the analysis and the interpretation of extracts from legislation and articles written on the proposed changes. The current “gross income” of a taxpayer consists of amounts earned from a source within or deemed to be from within Zimbabwe The proposed changes to the Act will change the tax system to a residence-based system, where resident taxpayers are taxed on amounts earned from all sources. Therefore, the driving factor which determines the taxability of an amount will become the taxpayer’s residency. Clause 2 of the proposed Act provides that income earned by a taxpayer should be separated into employment income, business income, property income and other specified income. This will make it unnecessary to determine the nature of an amount because capital amounts will be subject to income tax. The current Act provides for the deduction of expenditure incurred for the purpose of trade or in the production of income. Section 31(1)(a) of the proposed Act will restrict permissible deductions to expenditure incurred in the production of income. Consequently, expenditure not incurred for the purpose of earning income will no longer be deductible when the Income Tax Bill is implemented. The proposed Income Tax Act will increase the taxable income of a taxpayer as it makes amounts that are not currently subject to tax taxable, whilst restricting the deductions claimable.
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A Framework for using Open Source intelligence as a Digital Forensic Investigative tool
- Authors: Rule, Samantha Elizabeth
- Date: 2015
- Subjects: Open source intelligence , Criminal investigation , Electronic evidence
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4715 , http://hdl.handle.net/10962/d1017937
- Description: The proliferation of the Internet has amplified the use of social networking sites by creating a platform that encourages individuals to share information. As a result there is a wealth of information that is publically and easily accessible. This research explores whether open source intelligence (OSINT), which is freely available, could be used as a digital forensic investigative tool. A survey was created and sent to digital forensic investigators to establish whether they currently use OSINT when performing investigations. The survey results confirm that OSINT is being used by digital forensic investigators when performing investigations but there are currently no guidelines or frameworks available to support the use thereof. Additionally, the survey results showed a belief amongst those surveyed that evidence gleaned from OSINT sources is considered supplementary rather than evidentiary. The findings of this research led to the development of a framework that identifies and recommends key processes to follow when conducting OSINT investigations. The framework can assist digital forensic investigators to follow a structured and rigorous process, which may lead to the unanimous acceptance of information obtained via OSINT sources as evidentiary rather than supplementary in the near future.
- Full Text:
- Authors: Rule, Samantha Elizabeth
- Date: 2015
- Subjects: Open source intelligence , Criminal investigation , Electronic evidence
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4715 , http://hdl.handle.net/10962/d1017937
- Description: The proliferation of the Internet has amplified the use of social networking sites by creating a platform that encourages individuals to share information. As a result there is a wealth of information that is publically and easily accessible. This research explores whether open source intelligence (OSINT), which is freely available, could be used as a digital forensic investigative tool. A survey was created and sent to digital forensic investigators to establish whether they currently use OSINT when performing investigations. The survey results confirm that OSINT is being used by digital forensic investigators when performing investigations but there are currently no guidelines or frameworks available to support the use thereof. Additionally, the survey results showed a belief amongst those surveyed that evidence gleaned from OSINT sources is considered supplementary rather than evidentiary. The findings of this research led to the development of a framework that identifies and recommends key processes to follow when conducting OSINT investigations. The framework can assist digital forensic investigators to follow a structured and rigorous process, which may lead to the unanimous acceptance of information obtained via OSINT sources as evidentiary rather than supplementary in the near future.
- Full Text:
The protein and energy requirements of the South African abalone, Haliotis midae
- Authors: Green, Alistair John
- Date: 2009
- Subjects: Haliotis midae -- South Africa Abalone culture -- South Africa Abalones -- Nutrition Abalones -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5352 , http://hdl.handle.net/10962/d1008261
- Description: The abalone (Haliotis midae) culture industry in South Africa is becoming increasingly dependent on the use of formulated feeds, due to limitations in the supply of kelp. The bulk of the feeds that are currently available were developed based on the requirements of juvenile abalone cultured within the optimal temperature range for growth (18 - 20 °C). However, most abalone farming facilities are land-based pump ashore operations and are thus mostly exposed to temperatures outside of this range. In addition, these feeds have been found to be unsuitable for abalone cultured at elevated water temperatures (> 20°C). The aim of the study was to develop size and temperature specific diets for H midoe through optimisation of dietary protein, energy and lipid levels. Abalone were cultured under farm-like conditions in three partially recirculating temperature controlled systems at either 18, 22 or 24°C and fed formulated diets containing graded levels of protein (18,22 and 26 %) and energy (11.6, 13.5 and 16.2 MJ.kg·I ). Abalone were stocked into baskets at 5 % of available of surface area (n=36) and each diet (n=9) was fed to four baskets of abalone at each of the three temperature regimes for ten weeks. Abalone growth was temperature dependent, with growth declining from 4.33 g.month-I for abalone cultured at 18°C to 0.77 g.month-I at 24°C. Dietary protein could be reduced from 26 to 18 % provided dietary energy levels were maintained at 13.5 MJ.kg- l • A dietary energy level of 11.6 MJ.kg-1 was insufficient to meet the energetic requirements of H midae regardless of the protein content of the diet. The effects of water temperature and body size on the protein requirements of H midae were investigated by culturing abalone at temperatures within the optimal range for abalone farming (i.e. 14, 16 and 18°C). Three size classes of abalone (15, 50 and 80 mm) were fed formulated feed containing graded levels of dietary protein (20, 26, 32, 38 and 44 %) under controlled laboratory conditions for 12 weeks, and, in a separate experiment, under commercial farm conditions for 24 weeks. It was not possible to convincingly define the optimal protein levels for abalone of different sizes in this experiment because growth rates fell below average commercial growth rates obtained on farms. Growth was temperature dependent in the laboratory trial, with the rate of weight gain of the 15 mm (ANOV A: p=0.002) and 50 mm abalone (ANOV A: p=0.02) increasing significantly with an increase in temperature from 14 to 18°C. In the farm trial, dietary protein content did not affect the growth rate of the 10-15 or 80 mm abalone (ANOVA: p>0.05), however, the 50 mm abalone displayed significantly higher weight gain on the 32 % (4.72±0.20 g.month-I ) and 38 % (5.01±0.34 g.month-I ) protein diets compared to those fed the 20 % protein diet (3.75±0.13 g.month-I ) (ANOVA: p=O.OI). Although definition of optimal dietary protein levels were not possible, the effects of dietary protein content and water temperature on the growth of H midae were independent signifying that the protein requirements of abalone are temperature independent. In addition, there was no evidence to indicate that abalone of the different sizes tested here had different dietary protein requirements. The size specific dietary lipid and protein requirements of H midae were investigated by feeding two size classes of abalone (30 and 60 mm initial shell length) diets containing graded levels of dietary lipid (4, 7, 10, 13 and 16 %) and protein (34 - 39 %) for 12 weeks. The 30 and 60 mm abalone were stocked at 7 (n=200) and 9 % (n=36) of the available basket surface area respectively and each diet was fed to four baskets of abalone of each size class. The protein requirements of H. midae are influenced by the amount of available dietary energy and thus it is possible that the ability of abalone to utilise lipids as a source of energy differs in the presence of varying levels of dietary protein. High levels of dietary lipid negatively affected the growth, condition factor and soft tissue glycogen content of both size classes of abalone. This negative effect was greater in the 30 mm size class compared to the 60 mm abalone. The corresponding increase in feed consumption and feed conversion ratio in response to increasing levels of dietary protein also provides evidence that abalone are unable to utilise dietary lipids as an energy source and high levels of dietary lipid probably inhibit the uptake of carbohydrates and protein. High dietary lipid levels did however appear to promote gonad maturation. It was possible to reduce dietary protein from 34 to 20 % without negatively affecting growth through the maintenance of dietary energy levels and thus it is recommended that future experiments on the energy content of formulated feeds should focus on the improved use of carbohydrates. Reductions in the protein portion of formulated feeds for H. midae are possible provided the diet contains sufficient levels of energy supplied from carbohydrates. As the ability of abalone to utilise dietary lipid is limited, lipids are unlikely to play a significant role as an energy source in abalone feeds. Further investigations should focus on the utilisation of various carbohydrate sources in abalone feeds.
- Full Text:
- Authors: Green, Alistair John
- Date: 2009
- Subjects: Haliotis midae -- South Africa Abalone culture -- South Africa Abalones -- Nutrition Abalones -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5352 , http://hdl.handle.net/10962/d1008261
- Description: The abalone (Haliotis midae) culture industry in South Africa is becoming increasingly dependent on the use of formulated feeds, due to limitations in the supply of kelp. The bulk of the feeds that are currently available were developed based on the requirements of juvenile abalone cultured within the optimal temperature range for growth (18 - 20 °C). However, most abalone farming facilities are land-based pump ashore operations and are thus mostly exposed to temperatures outside of this range. In addition, these feeds have been found to be unsuitable for abalone cultured at elevated water temperatures (> 20°C). The aim of the study was to develop size and temperature specific diets for H midoe through optimisation of dietary protein, energy and lipid levels. Abalone were cultured under farm-like conditions in three partially recirculating temperature controlled systems at either 18, 22 or 24°C and fed formulated diets containing graded levels of protein (18,22 and 26 %) and energy (11.6, 13.5 and 16.2 MJ.kg·I ). Abalone were stocked into baskets at 5 % of available of surface area (n=36) and each diet (n=9) was fed to four baskets of abalone at each of the three temperature regimes for ten weeks. Abalone growth was temperature dependent, with growth declining from 4.33 g.month-I for abalone cultured at 18°C to 0.77 g.month-I at 24°C. Dietary protein could be reduced from 26 to 18 % provided dietary energy levels were maintained at 13.5 MJ.kg- l • A dietary energy level of 11.6 MJ.kg-1 was insufficient to meet the energetic requirements of H midae regardless of the protein content of the diet. The effects of water temperature and body size on the protein requirements of H midae were investigated by culturing abalone at temperatures within the optimal range for abalone farming (i.e. 14, 16 and 18°C). Three size classes of abalone (15, 50 and 80 mm) were fed formulated feed containing graded levels of dietary protein (20, 26, 32, 38 and 44 %) under controlled laboratory conditions for 12 weeks, and, in a separate experiment, under commercial farm conditions for 24 weeks. It was not possible to convincingly define the optimal protein levels for abalone of different sizes in this experiment because growth rates fell below average commercial growth rates obtained on farms. Growth was temperature dependent in the laboratory trial, with the rate of weight gain of the 15 mm (ANOV A: p=0.002) and 50 mm abalone (ANOV A: p=0.02) increasing significantly with an increase in temperature from 14 to 18°C. In the farm trial, dietary protein content did not affect the growth rate of the 10-15 or 80 mm abalone (ANOVA: p>0.05), however, the 50 mm abalone displayed significantly higher weight gain on the 32 % (4.72±0.20 g.month-I ) and 38 % (5.01±0.34 g.month-I ) protein diets compared to those fed the 20 % protein diet (3.75±0.13 g.month-I ) (ANOVA: p=O.OI). Although definition of optimal dietary protein levels were not possible, the effects of dietary protein content and water temperature on the growth of H midae were independent signifying that the protein requirements of abalone are temperature independent. In addition, there was no evidence to indicate that abalone of the different sizes tested here had different dietary protein requirements. The size specific dietary lipid and protein requirements of H midae were investigated by feeding two size classes of abalone (30 and 60 mm initial shell length) diets containing graded levels of dietary lipid (4, 7, 10, 13 and 16 %) and protein (34 - 39 %) for 12 weeks. The 30 and 60 mm abalone were stocked at 7 (n=200) and 9 % (n=36) of the available basket surface area respectively and each diet was fed to four baskets of abalone of each size class. The protein requirements of H. midae are influenced by the amount of available dietary energy and thus it is possible that the ability of abalone to utilise lipids as a source of energy differs in the presence of varying levels of dietary protein. High levels of dietary lipid negatively affected the growth, condition factor and soft tissue glycogen content of both size classes of abalone. This negative effect was greater in the 30 mm size class compared to the 60 mm abalone. The corresponding increase in feed consumption and feed conversion ratio in response to increasing levels of dietary protein also provides evidence that abalone are unable to utilise dietary lipids as an energy source and high levels of dietary lipid probably inhibit the uptake of carbohydrates and protein. High dietary lipid levels did however appear to promote gonad maturation. It was possible to reduce dietary protein from 34 to 20 % without negatively affecting growth through the maintenance of dietary energy levels and thus it is recommended that future experiments on the energy content of formulated feeds should focus on the improved use of carbohydrates. Reductions in the protein portion of formulated feeds for H. midae are possible provided the diet contains sufficient levels of energy supplied from carbohydrates. As the ability of abalone to utilise dietary lipid is limited, lipids are unlikely to play a significant role as an energy source in abalone feeds. Further investigations should focus on the utilisation of various carbohydrate sources in abalone feeds.
- Full Text:
Concept development in aspects of ecology
- Authors: Webb, Paul
- Date: 1988
- Subjects: Ecology -- Study and teaching
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1354 , http://hdl.handle.net/10962/d1001420
- Description: In this study food webs and a case study are used to investigate concepts which university students and high school pupils hold about ecology and the degree to which concept development has taken place at particular educational levels. The sample was drawn from first year zoology students and biology pupils in standards eight and ten. Present data indicate that students and pupils could solve problems involving the interactions of populations only if they were simple enough to be answered using strategies based on the food chain concept. Very few subjects could succesfully determine all the interacting pathways along which effects may be transmitted within a food web. The ability to determine all the pathways along which the effects of a change in population numbers within a community are spread, and to analyse the possible net manifestation of sometimes conflicting forces, requires a clear understanding of the concept of food web. An immature understanding of the food web concept by the subjects of this study is suggested as, in most cases, they identified alternate pathways within the food web when explicitly asked to do so, but did not apply this strategy when asked to solve problems based on the same principle. The case study also revealed immature ecological concepts. Responses by standard eight pupils indicate that the opportunity exists at this level to develop a clear and mature understanding of the concept of food web, while comparison of data provided by the three age groups suggests that if clear conceptual development regarding food webs does not take place at school, misconceptions are likely to persist among first year university students.
- Full Text:
- Authors: Webb, Paul
- Date: 1988
- Subjects: Ecology -- Study and teaching
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1354 , http://hdl.handle.net/10962/d1001420
- Description: In this study food webs and a case study are used to investigate concepts which university students and high school pupils hold about ecology and the degree to which concept development has taken place at particular educational levels. The sample was drawn from first year zoology students and biology pupils in standards eight and ten. Present data indicate that students and pupils could solve problems involving the interactions of populations only if they were simple enough to be answered using strategies based on the food chain concept. Very few subjects could succesfully determine all the interacting pathways along which effects may be transmitted within a food web. The ability to determine all the pathways along which the effects of a change in population numbers within a community are spread, and to analyse the possible net manifestation of sometimes conflicting forces, requires a clear understanding of the concept of food web. An immature understanding of the food web concept by the subjects of this study is suggested as, in most cases, they identified alternate pathways within the food web when explicitly asked to do so, but did not apply this strategy when asked to solve problems based on the same principle. The case study also revealed immature ecological concepts. Responses by standard eight pupils indicate that the opportunity exists at this level to develop a clear and mature understanding of the concept of food web, while comparison of data provided by the three age groups suggests that if clear conceptual development regarding food webs does not take place at school, misconceptions are likely to persist among first year university students.
- Full Text:
Influence of local economic development strategic leaders on the formulation of the integrated development plan, Makana Municipality, Eastern Cape
- Authors: Nonxuba, Mnweba McNair
- Date: 2014
- Subjects: Local Economic Development (Programme) , Community development -- South Africa -- Grahamstown , Municipal government -- South Africa -- Grahamstown , Strategic planning -- South Africa -- Grahamstown , Grahamstown (South Africa) -- Economic conditions -- 21st century , South Africa -- Politics and government
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:832 , http://hdl.handle.net/10962/d1013176
- Description: The influence of local economic development strategic leaders on how Integrated Development Plans (IDP) are developed is critical to gain insights into strategic planning directed towards economically developing municipalities. Concisely, the aim of this qualitative study was to gain a multiple understanding of how LED strategic leaders, namely managers of the LED directorate and sub-directorates at Makana local municipality influenced the IDP formulation. The fact that these LED strategic leaders, ‘make consequential or strategic decisions’ suggests that their decisions have an influence on the IDP formulation. Thus, the key research question in this study was: How do LED strategic leaders at Makana local municipality influence the formulation of the IDP at this municipality? This qualitative research used purposive sampling of incidents upheld by LED Strategic leaders. A total of ten in-depth and semi-structured interviews were conducted with four LED strategic leaders regarding incidents of their perceived influence on the formulation of the Integrated Development Plan at Makana. The interviews were in-depth in order to gain a rich understanding of their perspectives of reality. As the number of LED strategic leaders was already very small, all the four leaders at Makana participated in this study. Interview data was transcribed and analyzed using open coding and constant comparison. Member check was conducted to enhance confirmability of the findings of this study. Findings indicate that LED strategic leaders perceived their influence on the formulation of the IDP Makana municipality in four varied ways. Predominantly, LED strategic leaders commonly perceived that they had influence in setting evidence-driven direction, and searching for fitness of activities and issues with LED strategy. Thereafter, the other ways in which these LED strategic leaders perceived how they influenced the IDP formulation involve the facilitation of clarity and local relevance of LED mandates, and finally the integration of multiple economic voices of stakeholders. This demonstrates that LED strategic leaders at Makana emphasize proactively managing strategy process rather than content in terms of identifying key opportunities and major economic drivers in the local milieu. Instead, they perceived their influence as characterized by enhancing compliance with bringing the process of municipal strategy formulation closer to stakeholders. Implications of these findings are highlighted.
- Full Text:
- Authors: Nonxuba, Mnweba McNair
- Date: 2014
- Subjects: Local Economic Development (Programme) , Community development -- South Africa -- Grahamstown , Municipal government -- South Africa -- Grahamstown , Strategic planning -- South Africa -- Grahamstown , Grahamstown (South Africa) -- Economic conditions -- 21st century , South Africa -- Politics and government
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:832 , http://hdl.handle.net/10962/d1013176
- Description: The influence of local economic development strategic leaders on how Integrated Development Plans (IDP) are developed is critical to gain insights into strategic planning directed towards economically developing municipalities. Concisely, the aim of this qualitative study was to gain a multiple understanding of how LED strategic leaders, namely managers of the LED directorate and sub-directorates at Makana local municipality influenced the IDP formulation. The fact that these LED strategic leaders, ‘make consequential or strategic decisions’ suggests that their decisions have an influence on the IDP formulation. Thus, the key research question in this study was: How do LED strategic leaders at Makana local municipality influence the formulation of the IDP at this municipality? This qualitative research used purposive sampling of incidents upheld by LED Strategic leaders. A total of ten in-depth and semi-structured interviews were conducted with four LED strategic leaders regarding incidents of their perceived influence on the formulation of the Integrated Development Plan at Makana. The interviews were in-depth in order to gain a rich understanding of their perspectives of reality. As the number of LED strategic leaders was already very small, all the four leaders at Makana participated in this study. Interview data was transcribed and analyzed using open coding and constant comparison. Member check was conducted to enhance confirmability of the findings of this study. Findings indicate that LED strategic leaders perceived their influence on the formulation of the IDP Makana municipality in four varied ways. Predominantly, LED strategic leaders commonly perceived that they had influence in setting evidence-driven direction, and searching for fitness of activities and issues with LED strategy. Thereafter, the other ways in which these LED strategic leaders perceived how they influenced the IDP formulation involve the facilitation of clarity and local relevance of LED mandates, and finally the integration of multiple economic voices of stakeholders. This demonstrates that LED strategic leaders at Makana emphasize proactively managing strategy process rather than content in terms of identifying key opportunities and major economic drivers in the local milieu. Instead, they perceived their influence as characterized by enhancing compliance with bringing the process of municipal strategy formulation closer to stakeholders. Implications of these findings are highlighted.
- Full Text:
Investigating the relationship between sustainability and farmer decision-making: a qualitative study of maize farmers in Mpumalanga, South Africa
- Authors: Grewar, Robert
- Date: 2011
- Subjects: Sustainable agriculture -- Research -- South Africa Agriculture -- South Africa -- Decision making Corn -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:785 , http://hdl.handle.net/10962/d1003906
- Description: The goal of the research paper was to understand the complex relationship between the issue of sustainability and maize farmers’ decision-making processes. The aim is to shed light on the realities experienced by maize farmers in terms of how sustainability impacts on the decisions they make and how the decisions they make impact on sustainability. The importance of the research lies in the current state of affairs in the world in terms of the current economic recession, overpopulation, dire poverty and hunger, and the poor state of the environment. If humankind is to continue its existence on Earth in a happy, healthy world, something is going to have to give. In order for this to happen, people need to start grappling with the concept of sustainability. Focusing on sustainability as a whole is likely to end in despair. However, breaking the problem down into its component pieces will allow people to influence the particular sector in which they operate. It is therefore imperative for research into sustainability to be undertaken in all sectors of society and the economy. Agriculture presents an excellent research area due to its intrinsic link with the environment, society and the economy. Agriculture and its wellbeing is inextricably tied to environmental health. Healthy plants and animals will not grow in unhealthy conditions. Society is to a large degree dependent on agriculture for food, agriculture therefore has a significant impact on social order and function. Agriculture is one of the primary contributors to GDP, particularly in poor and developing nations. As a result, agriculture has an important role to play in ensuring economic sustainability. In order to engage with sustainability from an agricultural perspective it was decided to engage on the farmer-level. Gaining an understanding of their reality in terms of what motivates their decisions is key to understanding the relationship between agriculture and sustainability. Three maize farmers in Mpumalanga, South Africa, were interviewed with the aim of collecting qualitative data and then analysing the data using thematic analysis. The methodology employed enabled the researcher to uncover patterns in the data that constituted themes across the interviews. The following themes emerged: Theme 1: Economic factors are the primary decision driver. This is primarily due to the extent of the financial risk experienced by farmers as a result of market risk, production risk, finance risk, and rising input costs. This results in economic considerations superseding environmental or social concerns in farmers’ decisions. This has a negative impact on the overall sustainability of the farming operation. Theme 2: There has been a decrease in the number of family-run farms. This is attributable to a number of factors including economic failure, fear of loss of land due to land-reform policies, as well as crime. Family-run farms tend to have a greater focus on sustainability due to the vested interest in the next generation taking over the farm. The corporate farming operations that are taking over the farms tend to be more focussed on short-term gains in order to satisfy shareholders. Theme 3: Mechanisation is preferable to manual labour. There has been an alarming decrease in the number of labourers employed on farms. Farmers say this is due to two factors. Firstly, machines are more efficient than labour. Secondly, restrictive labour laws have made famers less keen to employ people. The net effect of these two factors is that unemployment is rising. This has negative consequences for society, the economy, and the environment. Theme 4: Farmers believe they do very little environmental damage. This results in decisions being made that do not consider environmental wellbeing other than soil health. This is because farmers see healthy soil as an integral input that optimises economic performance. Farmers tend to prioritise economic factors in their decisions more than environmental or social factors. This results in an unsustainable perspective. The only ways in which this is likely to change is if the financial risk associated with agriculture is decreased, or if farmers are given financial incentive to change their ways. In order to deal with this issue it is necessary for further research to be conducted. Research needs to be conducted to confirm the results of this study. It is important to know whether the results pertain only to maize farmers in Mpumalanga or whether most farmers in South Africa, and indeed the world, face similar problems. Research should also be conducted to propose policies or procedures to reduce financial risk in agriculture. Research should focus on reducing market risk and reducing input costs, possibly via subsidisation.
- Full Text:
- Authors: Grewar, Robert
- Date: 2011
- Subjects: Sustainable agriculture -- Research -- South Africa Agriculture -- South Africa -- Decision making Corn -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:785 , http://hdl.handle.net/10962/d1003906
- Description: The goal of the research paper was to understand the complex relationship between the issue of sustainability and maize farmers’ decision-making processes. The aim is to shed light on the realities experienced by maize farmers in terms of how sustainability impacts on the decisions they make and how the decisions they make impact on sustainability. The importance of the research lies in the current state of affairs in the world in terms of the current economic recession, overpopulation, dire poverty and hunger, and the poor state of the environment. If humankind is to continue its existence on Earth in a happy, healthy world, something is going to have to give. In order for this to happen, people need to start grappling with the concept of sustainability. Focusing on sustainability as a whole is likely to end in despair. However, breaking the problem down into its component pieces will allow people to influence the particular sector in which they operate. It is therefore imperative for research into sustainability to be undertaken in all sectors of society and the economy. Agriculture presents an excellent research area due to its intrinsic link with the environment, society and the economy. Agriculture and its wellbeing is inextricably tied to environmental health. Healthy plants and animals will not grow in unhealthy conditions. Society is to a large degree dependent on agriculture for food, agriculture therefore has a significant impact on social order and function. Agriculture is one of the primary contributors to GDP, particularly in poor and developing nations. As a result, agriculture has an important role to play in ensuring economic sustainability. In order to engage with sustainability from an agricultural perspective it was decided to engage on the farmer-level. Gaining an understanding of their reality in terms of what motivates their decisions is key to understanding the relationship between agriculture and sustainability. Three maize farmers in Mpumalanga, South Africa, were interviewed with the aim of collecting qualitative data and then analysing the data using thematic analysis. The methodology employed enabled the researcher to uncover patterns in the data that constituted themes across the interviews. The following themes emerged: Theme 1: Economic factors are the primary decision driver. This is primarily due to the extent of the financial risk experienced by farmers as a result of market risk, production risk, finance risk, and rising input costs. This results in economic considerations superseding environmental or social concerns in farmers’ decisions. This has a negative impact on the overall sustainability of the farming operation. Theme 2: There has been a decrease in the number of family-run farms. This is attributable to a number of factors including economic failure, fear of loss of land due to land-reform policies, as well as crime. Family-run farms tend to have a greater focus on sustainability due to the vested interest in the next generation taking over the farm. The corporate farming operations that are taking over the farms tend to be more focussed on short-term gains in order to satisfy shareholders. Theme 3: Mechanisation is preferable to manual labour. There has been an alarming decrease in the number of labourers employed on farms. Farmers say this is due to two factors. Firstly, machines are more efficient than labour. Secondly, restrictive labour laws have made famers less keen to employ people. The net effect of these two factors is that unemployment is rising. This has negative consequences for society, the economy, and the environment. Theme 4: Farmers believe they do very little environmental damage. This results in decisions being made that do not consider environmental wellbeing other than soil health. This is because farmers see healthy soil as an integral input that optimises economic performance. Farmers tend to prioritise economic factors in their decisions more than environmental or social factors. This results in an unsustainable perspective. The only ways in which this is likely to change is if the financial risk associated with agriculture is decreased, or if farmers are given financial incentive to change their ways. In order to deal with this issue it is necessary for further research to be conducted. Research needs to be conducted to confirm the results of this study. It is important to know whether the results pertain only to maize farmers in Mpumalanga or whether most farmers in South Africa, and indeed the world, face similar problems. Research should also be conducted to propose policies or procedures to reduce financial risk in agriculture. Research should focus on reducing market risk and reducing input costs, possibly via subsidisation.
- Full Text:
An exploratory case study of accelerator programmes in the Republic of South Africa
- Authors: Mametse, Mmankitseng Lerato
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/92639 , vital:30737
- Description: South Africa is facing a challenge of poverty, unemployment and low growth. Government has identified the small and medium-sized business (SME) sector as one of the ways through which to combat these challenges. Government has also set up programmes and agencies to support SMEs in their search for funding and other kinds of support. South Africa, however, has one of the highest rates of SME failures in the world, with the majority not surviving beyond three years. Alternative interventions are therefore required to support South Africa’s SMEs to become sustainable companies beyond three years and to contribute positively to economic growth, poverty alleviation and job creation. This paper explores one kind of intervention that has been used internationally and that is increasingly being adopted in South Africa. Accelerator programmes, aimed at supporting start-ups to get to the next level of their development, have been growing in numbers around the world, trying to replicate the success of the original accelerator programme – the Y Combinator – which was responsible for the success of household names such as Airbnb and Dropbox. Accelerator programmes help start-up companies define and build their initial products, identify promising customer segments, and secure resources, including capital and employees. By making these necessary resources available to start-ups, it may be possible to ensure that fewer start-ups fail and more SMEs remain sustainable into the future. Several accelerator programmes have been founded in South Africa, all with a similar aim: to accelerate the development of start-ups that have the potential to grow exponentially given access to the right resources. This paper examines how South African accelerator programmes work in terms of the key resources made available to the start-ups that participate in their programmes. An increasing number of academic papers have been written on accelerator programmes internationally, but little information is available for the South African context. This research study investigated the phenomenon of accelerator programmes in South Africa through the lens of Resource-based Theory. The theory posits that, in order to gain a sustained competitive advantage, companies need to utilise their resources (including physical, human and organisational) in a manner that is effective and efficient, both internally and externally. The research answers the following questions: How do accelerator programmes work in South Africa? What value (in terms of resources offered) do they claim to bring to start-ups that go through their accelerator programmes? An exploratory case study method was selected to understand the phenomenon of accelerator programmes in South Africa. Purposeful sampling was used in the selection of accelerator programmes, as it allows for the selection of information-rich cases. The research findings indicate that accelerator programmes in South Africa follow the structure of providing start-ups, over a period between three months and one year, with resources that will assist them to be successful into the future. The investigation finds that human and financial resources are some of the most valuable resources that accelerator programmes provide to start-ups to help progress these start-ups to their next level of development. The most important resource is mentorship from knowledgeable industry players who are themselves entrepreneurs. Access to networks to gain access to the market, as well as funding, is also made available by accelerator programmes. This investigation provides a glimpse of the accelerator programme phenomenon in South Africa and highlights the important role that mentorship from experienced entrepreneurs, and access to markets and funding, play in the development of start-ups.
- Full Text:
- Authors: Mametse, Mmankitseng Lerato
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/92639 , vital:30737
- Description: South Africa is facing a challenge of poverty, unemployment and low growth. Government has identified the small and medium-sized business (SME) sector as one of the ways through which to combat these challenges. Government has also set up programmes and agencies to support SMEs in their search for funding and other kinds of support. South Africa, however, has one of the highest rates of SME failures in the world, with the majority not surviving beyond three years. Alternative interventions are therefore required to support South Africa’s SMEs to become sustainable companies beyond three years and to contribute positively to economic growth, poverty alleviation and job creation. This paper explores one kind of intervention that has been used internationally and that is increasingly being adopted in South Africa. Accelerator programmes, aimed at supporting start-ups to get to the next level of their development, have been growing in numbers around the world, trying to replicate the success of the original accelerator programme – the Y Combinator – which was responsible for the success of household names such as Airbnb and Dropbox. Accelerator programmes help start-up companies define and build their initial products, identify promising customer segments, and secure resources, including capital and employees. By making these necessary resources available to start-ups, it may be possible to ensure that fewer start-ups fail and more SMEs remain sustainable into the future. Several accelerator programmes have been founded in South Africa, all with a similar aim: to accelerate the development of start-ups that have the potential to grow exponentially given access to the right resources. This paper examines how South African accelerator programmes work in terms of the key resources made available to the start-ups that participate in their programmes. An increasing number of academic papers have been written on accelerator programmes internationally, but little information is available for the South African context. This research study investigated the phenomenon of accelerator programmes in South Africa through the lens of Resource-based Theory. The theory posits that, in order to gain a sustained competitive advantage, companies need to utilise their resources (including physical, human and organisational) in a manner that is effective and efficient, both internally and externally. The research answers the following questions: How do accelerator programmes work in South Africa? What value (in terms of resources offered) do they claim to bring to start-ups that go through their accelerator programmes? An exploratory case study method was selected to understand the phenomenon of accelerator programmes in South Africa. Purposeful sampling was used in the selection of accelerator programmes, as it allows for the selection of information-rich cases. The research findings indicate that accelerator programmes in South Africa follow the structure of providing start-ups, over a period between three months and one year, with resources that will assist them to be successful into the future. The investigation finds that human and financial resources are some of the most valuable resources that accelerator programmes provide to start-ups to help progress these start-ups to their next level of development. The most important resource is mentorship from knowledgeable industry players who are themselves entrepreneurs. Access to networks to gain access to the market, as well as funding, is also made available by accelerator programmes. This investigation provides a glimpse of the accelerator programme phenomenon in South Africa and highlights the important role that mentorship from experienced entrepreneurs, and access to markets and funding, play in the development of start-ups.
- Full Text:
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