The allelopathic potential of Arctotis Arctotoides (L.f.) O. Hoffm on some vegetables
- Authors: Badmus, Abimbola Adesile
- Date: 2012
- Subjects: Allelopathy , Allelopathic agents , Vegetables -- Microbiology , Enzyme inhibitors
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11306 , http://hdl.handle.net/10353/454 , Allelopathy , Allelopathic agents , Vegetables -- Microbiology , Enzyme inhibitors
- Description: Laboratory and greenhouse experiments were conducted to evaluate the allelopathic effects of the extracts and residue Arctotis arctotoides (L.f.) O. Hoffm on selected vegetable crops. The study aimed to address the following specific objectives to (i) examine the ultra structures of the leaf of A. arctotoides using the Scanning Electron Microscope (SEM), (ii) carry out comprehensive qualitative and quantitative phytochemical analysis of the root and shoot materials of the plant, (iii) investigate the allelopathic activities of the root and shoot aqueous extracts of A. arctotoides at concentrations of 10, 8, 6, 4 and 2 mg/ml on germination, radicle and plumule growth of cabbage, carrot, tomato and spinach, (iv) evaluate the inhibitory effects of the dried shoot residue of the plant at 10, 20 and 40 g kg-3 of soil (treatments B, C and D) and the control (treatment A) on the morphology, growth and chlorophyll pigment content of tomato and cabbage transplants at 1, 2, 3 and 4 weeks after transplanting and (v) assess the effects of the dried shoot residue of A. arctotoides on the yield, nutrient uptake by the leaves of tomato and cabbage at 4 and 12 weeks after transplanting. Finally, to analyze the residual mineral content of the soils with tomato and cabbage transplants at 12 weeks after transplanting. The the SEM revealed that anisocytic stomata and glandular trichomes (GTs) were numerous on the abaxial than the adaxial surfaces of A. arctotoides. The non glandular trichomes (NGTs) were also present on both surfaces but lesser on the abaxial. Morphologically, the GTs were peltate, uniseriate and globular head while the NGTs were cylindrical and filamentous with variable number of cells at the basal portion. The energy dispersive X-ray spectroscopy of some crystals showed that Na+ Mg2+ and Ca2+ were the major constituents of the crystal deposit found around the GTs and stomata. The results of the phytochemical composition of the root and shoot extracts of A. arctotoides confirmed the occurrence of alkaloids, flavonoids, phenolics, saponnins, tannins and triterpenes as the common constituents. In addition, cardiac glycosides and steroids were also detected in the shoot of the A. arctotoides. Quantitative estimation of the chemical constituents of the crude extracts further revealed that the alkaloid content in the root higher (0.97 percent) than the shoot (0.64 percent). The quantity of flavonoids detected in the shoot (1.02 percent) was more than that observed in the root (0.35 percent). Others (phenolics and tannins) were marginal in the two plant parts. The results of the inhibitory effects of the root and shoot aqueous extract at the varying concentrations showed that root extract at 10 mg/ml considerably reduced the germination of cabbage, carrot, tomato and spinach seeds by 84.0, 83.2, 72.8 and 37.4 percent respectively. Incubation of the shoot extract at the same concentration resulted in 100 percent inhibition of cabbage and carrot seed germination whereas those of tomato and spinach were suppressed by 91.5 and 61.2 percent respectively. The two extracts at the varying concentrations also had a significant reduction on the radicle and plumule growth of the four vegetables. Addition of the shoot residue to the soil showed massive chlorosis, necrotic lesions and wilting of tomato and cabbage leaves under treatments C and D at 2 weeks after transplanting. The number of leaves, leaf area, dry shoot and root weight of the two vegetables grown in the amended soils were also drastically reduced. The inhibition percentages due to the addition of the three concentrations of A. arctotoides dried shoot residue on the dry shoot weight at 4 weeks after transplanting were 38.6, 45.5 and 70.3. for tomato and 57.5, 73.3 and 87.5 percent for cabbage. Similarly, the declines in the dry root weight of 61.3, 82.9.4 and 83.4 percent for tomato as well as 53.1, 54.7 and 67.2 percent for cabbages were recorded for the two vegetables under treatment B, C and D during the period. The results further showed that the dry fruit yield and shoot weight of tomato under the treatments B, C and D decreased with increase in shoot residue concentrations of A. arctotoides. Relative to treatment A, no significant differences were recorded in the dry head weight of cabbage under the residue treated groups. The reductions in the fruit yield and fresh head weight caused by treatments C and D were 37.2 and 84.8 percent for tomato and 30.9 and 72.4 percent for cabbage. The findings on the mineral contents in the leaves of the two vegetables revealed significant differences in the uptake of N, Mg, Na, Cu and Fe by tomato leaves. The concentrations of N, K, Na and Zn in cabbage leaves also differed. However, the P content was relatively constant in the leaves of the two vegetables at 4 and 12 weeks after transplanting. At 12 weeks after transplanting, the Fe content in soils with tomato and cabbage treatments C and D was greatly enhanced in comparison with the other nutrients. The residual N, P and Zn detected in soils planted to cabbage were similarly equal among all the groups including the control. Thus, under the greenhouse experiment, Arctotis arctotoides (L.f) O. Hoffm has been shown to contain some phytotoxic chemical compounds in its root and shoot materials. The compounds either singly or collectively have demonstrated some inhibitory potentials on the germination, growth and yields of cabbage, carrot, tomato and spinach evaluated in this study.
- Full Text:
- Date Issued: 2012
- Authors: Badmus, Abimbola Adesile
- Date: 2012
- Subjects: Allelopathy , Allelopathic agents , Vegetables -- Microbiology , Enzyme inhibitors
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11306 , http://hdl.handle.net/10353/454 , Allelopathy , Allelopathic agents , Vegetables -- Microbiology , Enzyme inhibitors
- Description: Laboratory and greenhouse experiments were conducted to evaluate the allelopathic effects of the extracts and residue Arctotis arctotoides (L.f.) O. Hoffm on selected vegetable crops. The study aimed to address the following specific objectives to (i) examine the ultra structures of the leaf of A. arctotoides using the Scanning Electron Microscope (SEM), (ii) carry out comprehensive qualitative and quantitative phytochemical analysis of the root and shoot materials of the plant, (iii) investigate the allelopathic activities of the root and shoot aqueous extracts of A. arctotoides at concentrations of 10, 8, 6, 4 and 2 mg/ml on germination, radicle and plumule growth of cabbage, carrot, tomato and spinach, (iv) evaluate the inhibitory effects of the dried shoot residue of the plant at 10, 20 and 40 g kg-3 of soil (treatments B, C and D) and the control (treatment A) on the morphology, growth and chlorophyll pigment content of tomato and cabbage transplants at 1, 2, 3 and 4 weeks after transplanting and (v) assess the effects of the dried shoot residue of A. arctotoides on the yield, nutrient uptake by the leaves of tomato and cabbage at 4 and 12 weeks after transplanting. Finally, to analyze the residual mineral content of the soils with tomato and cabbage transplants at 12 weeks after transplanting. The the SEM revealed that anisocytic stomata and glandular trichomes (GTs) were numerous on the abaxial than the adaxial surfaces of A. arctotoides. The non glandular trichomes (NGTs) were also present on both surfaces but lesser on the abaxial. Morphologically, the GTs were peltate, uniseriate and globular head while the NGTs were cylindrical and filamentous with variable number of cells at the basal portion. The energy dispersive X-ray spectroscopy of some crystals showed that Na+ Mg2+ and Ca2+ were the major constituents of the crystal deposit found around the GTs and stomata. The results of the phytochemical composition of the root and shoot extracts of A. arctotoides confirmed the occurrence of alkaloids, flavonoids, phenolics, saponnins, tannins and triterpenes as the common constituents. In addition, cardiac glycosides and steroids were also detected in the shoot of the A. arctotoides. Quantitative estimation of the chemical constituents of the crude extracts further revealed that the alkaloid content in the root higher (0.97 percent) than the shoot (0.64 percent). The quantity of flavonoids detected in the shoot (1.02 percent) was more than that observed in the root (0.35 percent). Others (phenolics and tannins) were marginal in the two plant parts. The results of the inhibitory effects of the root and shoot aqueous extract at the varying concentrations showed that root extract at 10 mg/ml considerably reduced the germination of cabbage, carrot, tomato and spinach seeds by 84.0, 83.2, 72.8 and 37.4 percent respectively. Incubation of the shoot extract at the same concentration resulted in 100 percent inhibition of cabbage and carrot seed germination whereas those of tomato and spinach were suppressed by 91.5 and 61.2 percent respectively. The two extracts at the varying concentrations also had a significant reduction on the radicle and plumule growth of the four vegetables. Addition of the shoot residue to the soil showed massive chlorosis, necrotic lesions and wilting of tomato and cabbage leaves under treatments C and D at 2 weeks after transplanting. The number of leaves, leaf area, dry shoot and root weight of the two vegetables grown in the amended soils were also drastically reduced. The inhibition percentages due to the addition of the three concentrations of A. arctotoides dried shoot residue on the dry shoot weight at 4 weeks after transplanting were 38.6, 45.5 and 70.3. for tomato and 57.5, 73.3 and 87.5 percent for cabbage. Similarly, the declines in the dry root weight of 61.3, 82.9.4 and 83.4 percent for tomato as well as 53.1, 54.7 and 67.2 percent for cabbages were recorded for the two vegetables under treatment B, C and D during the period. The results further showed that the dry fruit yield and shoot weight of tomato under the treatments B, C and D decreased with increase in shoot residue concentrations of A. arctotoides. Relative to treatment A, no significant differences were recorded in the dry head weight of cabbage under the residue treated groups. The reductions in the fruit yield and fresh head weight caused by treatments C and D were 37.2 and 84.8 percent for tomato and 30.9 and 72.4 percent for cabbage. The findings on the mineral contents in the leaves of the two vegetables revealed significant differences in the uptake of N, Mg, Na, Cu and Fe by tomato leaves. The concentrations of N, K, Na and Zn in cabbage leaves also differed. However, the P content was relatively constant in the leaves of the two vegetables at 4 and 12 weeks after transplanting. At 12 weeks after transplanting, the Fe content in soils with tomato and cabbage treatments C and D was greatly enhanced in comparison with the other nutrients. The residual N, P and Zn detected in soils planted to cabbage were similarly equal among all the groups including the control. Thus, under the greenhouse experiment, Arctotis arctotoides (L.f) O. Hoffm has been shown to contain some phytotoxic chemical compounds in its root and shoot materials. The compounds either singly or collectively have demonstrated some inhibitory potentials on the germination, growth and yields of cabbage, carrot, tomato and spinach evaluated in this study.
- Full Text:
- Date Issued: 2012
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
Ocean dynamics of the shelf and bays of the eastern Agulhas bank: a process-oriented numerical modelling study
- Authors: Bailey, Dylan Francis
- Date: 2020
- Subjects: Oceanography -- Research , Marine biology , Marine meteorology , Hydrography
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/49038 , vital:41595
- Description: There is a general need for a broader base of information on the finer detail of ocean processes in the Eastern Agulhas Bank region. In this thesis, the Regional Ocean Modelling System (ROMS) was applied to resolve high resolution (~1km) bay and shelf scale ocean processes along the south eastern coastline of South Africa using an offline multi-nested approach. Experimental and reference ocean model runs were used with in situ instrument mooring data to investigate how currents and temperature in the bays and the adjacent shelf are affected by the bathymetry, Agulhas Current (AC), regional winds, and coastal trapped waves (CTW). Focus was given to temperature, circulation, and coastal trapped waves, given the abundance of hourly in situ mooring data for these variables, making them suitable for comparison with the ocean model. SST variability trends were seasonally and spatially predictable, being greatest in the summer months and smallest in the winter months. A region of high SST variability extended from Port Alfred toward the south-west, indicating entrainment of nearshore upwelled water and instabilities in the inshore front of the AC. Shelf bottom temperature variability had a more spatially diverse seasonal trend, with coastal variability the highest (lowest) and offshore variability the lowest (highest) during the summer (winter) months. A distinct asymmetry in mean seasonal shelf bottom temperatures evident to the south of Algoa Bay and St Francis Bay was shown to be dependent on the profile of the shelf margin in relation to the inshore front of the AC using an experimental model run. Bay-scale anti-cyclonic circulation patterns dominate the bays throughout the year, with regions of strong mean surface currents occurring south of Cape Recife and Cape St Francis. General circulation patterns over the shelf are strongly governed by regional wind regimes, with the strongest flows being south-westward occurring during north-easterly wind events. Shelf bottom flows typically follow the expected Ekman-veering response, apart from near coastal flows that are topographically steered. A region of consistently strong south-westward shelf bottom flow extends from the east of Port Alfred to the shelf margin south of Bird Island. This flow is predominantly driven by the AC, although its velocity is strongly governed by regional winds. Circulation patterns during powerful eastward moving wind systems are strongly governed by the passage of associated CTW. Comparisons with an experimental model run where surface winds were removed revealed that the shelf wave was responsible for 61% of water volume displacement during a CTW event, and that the coastal shear turbulence caused by this displacement has a direct effect on the mixed layer depth. The links made between the complex shelf and bay ocean processes indicate that subtle changes to the ocean state will have far reaching effects on the regional ocean environment and its biota. Given the challenges of climate change, this is of paramount importance if we are to quantify these effects and mitigate their impacts, particularly with respect to the socio-economic dependency of those who rely on the ocean for its living resources.
- Full Text:
- Date Issued: 2020
- Authors: Bailey, Dylan Francis
- Date: 2020
- Subjects: Oceanography -- Research , Marine biology , Marine meteorology , Hydrography
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/49038 , vital:41595
- Description: There is a general need for a broader base of information on the finer detail of ocean processes in the Eastern Agulhas Bank region. In this thesis, the Regional Ocean Modelling System (ROMS) was applied to resolve high resolution (~1km) bay and shelf scale ocean processes along the south eastern coastline of South Africa using an offline multi-nested approach. Experimental and reference ocean model runs were used with in situ instrument mooring data to investigate how currents and temperature in the bays and the adjacent shelf are affected by the bathymetry, Agulhas Current (AC), regional winds, and coastal trapped waves (CTW). Focus was given to temperature, circulation, and coastal trapped waves, given the abundance of hourly in situ mooring data for these variables, making them suitable for comparison with the ocean model. SST variability trends were seasonally and spatially predictable, being greatest in the summer months and smallest in the winter months. A region of high SST variability extended from Port Alfred toward the south-west, indicating entrainment of nearshore upwelled water and instabilities in the inshore front of the AC. Shelf bottom temperature variability had a more spatially diverse seasonal trend, with coastal variability the highest (lowest) and offshore variability the lowest (highest) during the summer (winter) months. A distinct asymmetry in mean seasonal shelf bottom temperatures evident to the south of Algoa Bay and St Francis Bay was shown to be dependent on the profile of the shelf margin in relation to the inshore front of the AC using an experimental model run. Bay-scale anti-cyclonic circulation patterns dominate the bays throughout the year, with regions of strong mean surface currents occurring south of Cape Recife and Cape St Francis. General circulation patterns over the shelf are strongly governed by regional wind regimes, with the strongest flows being south-westward occurring during north-easterly wind events. Shelf bottom flows typically follow the expected Ekman-veering response, apart from near coastal flows that are topographically steered. A region of consistently strong south-westward shelf bottom flow extends from the east of Port Alfred to the shelf margin south of Bird Island. This flow is predominantly driven by the AC, although its velocity is strongly governed by regional winds. Circulation patterns during powerful eastward moving wind systems are strongly governed by the passage of associated CTW. Comparisons with an experimental model run where surface winds were removed revealed that the shelf wave was responsible for 61% of water volume displacement during a CTW event, and that the coastal shear turbulence caused by this displacement has a direct effect on the mixed layer depth. The links made between the complex shelf and bay ocean processes indicate that subtle changes to the ocean state will have far reaching effects on the regional ocean environment and its biota. Given the challenges of climate change, this is of paramount importance if we are to quantify these effects and mitigate their impacts, particularly with respect to the socio-economic dependency of those who rely on the ocean for its living resources.
- Full Text:
- Date Issued: 2020
Sedimentary, geochemical and geophysical study of the Ecca group, Karoo supergroup and its hydrocarbon potential in the Eastern Cape Province, South Africa
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
- Full Text:
- Date Issued: 2017
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
- Full Text:
- Date Issued: 2017
Access to credit and the effect of credit constraints on household welfare in the Eastern Cape province, South Africa
- Baiyegunhi, Lloyd-James Segun
- Authors: Baiyegunhi, Lloyd-James Segun
- Date: 2009
- Subjects: Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Investments -- South Africa -- Eastern Cape , Finance -- South Africa -- Eastern Cape , Credit -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11153 , http://hdl.handle.net/10353/d1000977 , Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Investments -- South Africa -- Eastern Cape , Finance -- South Africa -- Eastern Cape , Credit -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Description: In recent years, concern about food safety linked to health issues has seen a rise in private food safety standards in addition to the regulations set by the Food and Agriculture Organisation (FAO) in collaboration with the World Health Organisation (WHO). These have presented challenges to producers and exporters of agricultural food products especially the producers of fresh fruits and vegetables. In spite of the food safety-linked challenges from the demand side, the vast range of business-environment forces pose equally formidable challenges that negatively impact on the exporting industries’ ability to maintain or improve their market shares and their ability to compete in world markets. The objective of this study was therefore to establish the competitiveness of the South African citrus industry in the international markets within this prevailing scenario. Due to the diversity of the definitions of competitiveness as a concept, this study formulated the following working definition: “the ability to create, deliver and maintain value and constant market share through strategic management of the industrial environment or competitiveness drivers”. This was based on the understanding that the international market shares of an industry are a function of forces in the business environment which range from intra-industry, external and national as well as the international elements. The unit of analysis were the citrus producers engaged in export of their products and the study made use of 151 responses by producers. The study adopted a five-step approach to the analysis of the performance of the South African citrus industry in the global markets, starting with the analysis of the Constant Market Share (CMS) of the South African citrus industry in various world markets, establishing the impact of the business environmental factors upon competitiveness, establishing the costs of compliance with private food safety standards, determining the non-price benefits of compliance with the standards, as well as highlighting the strategies for enhancing long-term competitiveness of the industry in the international markets. South Africa is one of the top three countries dominating the citrus fruit export market. Since its entry into the citrus fruit exports market in the 1900s, the industry has sustained its activity in the international market. The Constant Market Share Analysis shows that, amidst the challenges on the international market side, and the changes in the business environment, over much of which the industry has limited control and influence, the industry has maintained its competitive advantage in several markets. The CMS shows that South Africa’s lemons are competitive in America. Despite a negative trend, the South African grapefruit has been competitive in France, Greece, Italy, the Netherlands and Spain. Oranges have been competitive in the Greece, Italy, Portugal, UK, Asian and Northern Europe markets. Competitiveness in these markets has been due to the inherent competitiveness of the industry. Competitiveness in such markets as the Middle East has been attributed to the relatively rapid growth of these markets. The South African citrus industry has similarly undergone many major processes of transformation. The business environmental factors influencing its performance have ranged reform to the challenges beyond the country’s borders. These factors directly and indirectly affect the performance of the industry in the export market. They have influenced the flow of fruits into different international destinations. Of major concern are the food safety and private standards. Challenges in traditional markets as well as opportunities presented by demand from newly emerging citrus consuming nations have seen a diversification in the marketing of the South African citrus. The intensity of competition in the global market is reflected by the fluctuations in the market shares in different markets as well as the increase and fluctuations of fruit rejection rates in some lucrative markets such as America. A combination of challenging national environmental forces and stringent demand conditions negatively impact on revenues especially from markets characterised by price competitiveness. This study identified cost of production, foreign market support systems, adaptability, worker skills, challenges of management in an international environment and government policies such as labour and trade policies as some of the most influential obstacles to competitiveness. Some of the most competiveness-enhancing factors were market availability, market size, market information, market growth and the availability of research institutions. However, compliance with private standards still poses a challenge to the exporters. The different performance levels of the industry in various markets prove the dissimilarity of the demand conditions in the global market. These are supported by the negative influence associated with the foreign market support regimes as well as the challenges associated with compliance with private food safety standards. While market availability, market growth, market information and size were identified as enhancing competitiveness, the fluctuations and inconsistencies in the competitiveness of the industry in different foreign markets require more than finding markets. Resource allocation by both the government and the industry may need to take into account the off-setting of the national challenges and support of farmers faced with distorted and unfair international playing fields. Otherwise, market availability is not a challenge for the industry save meeting the specifications therewith as well as price competitiveness which is unattainable for the South African citrus producers faced with high production costs. For the purposes of further study, it is recommended that account should be taken of all the products marketed by the industry (including processed products such as fruit juices) in order to have a whole picture of the competitiveness of the industry in the international market. This study also proffers a new theoretical framework for the analysis of the business environment for the citrus industry and other agro-businesses. This framework takes into account the indispensability of the food safety standards and measures as well as the diversity of the global consumer and the non-negotiability of food trade for the sustenance of the growing population.
- Full Text:
- Date Issued: 2009
- Authors: Baiyegunhi, Lloyd-James Segun
- Date: 2009
- Subjects: Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Investments -- South Africa -- Eastern Cape , Finance -- South Africa -- Eastern Cape , Credit -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11153 , http://hdl.handle.net/10353/d1000977 , Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Investments -- South Africa -- Eastern Cape , Finance -- South Africa -- Eastern Cape , Credit -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Description: In recent years, concern about food safety linked to health issues has seen a rise in private food safety standards in addition to the regulations set by the Food and Agriculture Organisation (FAO) in collaboration with the World Health Organisation (WHO). These have presented challenges to producers and exporters of agricultural food products especially the producers of fresh fruits and vegetables. In spite of the food safety-linked challenges from the demand side, the vast range of business-environment forces pose equally formidable challenges that negatively impact on the exporting industries’ ability to maintain or improve their market shares and their ability to compete in world markets. The objective of this study was therefore to establish the competitiveness of the South African citrus industry in the international markets within this prevailing scenario. Due to the diversity of the definitions of competitiveness as a concept, this study formulated the following working definition: “the ability to create, deliver and maintain value and constant market share through strategic management of the industrial environment or competitiveness drivers”. This was based on the understanding that the international market shares of an industry are a function of forces in the business environment which range from intra-industry, external and national as well as the international elements. The unit of analysis were the citrus producers engaged in export of their products and the study made use of 151 responses by producers. The study adopted a five-step approach to the analysis of the performance of the South African citrus industry in the global markets, starting with the analysis of the Constant Market Share (CMS) of the South African citrus industry in various world markets, establishing the impact of the business environmental factors upon competitiveness, establishing the costs of compliance with private food safety standards, determining the non-price benefits of compliance with the standards, as well as highlighting the strategies for enhancing long-term competitiveness of the industry in the international markets. South Africa is one of the top three countries dominating the citrus fruit export market. Since its entry into the citrus fruit exports market in the 1900s, the industry has sustained its activity in the international market. The Constant Market Share Analysis shows that, amidst the challenges on the international market side, and the changes in the business environment, over much of which the industry has limited control and influence, the industry has maintained its competitive advantage in several markets. The CMS shows that South Africa’s lemons are competitive in America. Despite a negative trend, the South African grapefruit has been competitive in France, Greece, Italy, the Netherlands and Spain. Oranges have been competitive in the Greece, Italy, Portugal, UK, Asian and Northern Europe markets. Competitiveness in these markets has been due to the inherent competitiveness of the industry. Competitiveness in such markets as the Middle East has been attributed to the relatively rapid growth of these markets. The South African citrus industry has similarly undergone many major processes of transformation. The business environmental factors influencing its performance have ranged reform to the challenges beyond the country’s borders. These factors directly and indirectly affect the performance of the industry in the export market. They have influenced the flow of fruits into different international destinations. Of major concern are the food safety and private standards. Challenges in traditional markets as well as opportunities presented by demand from newly emerging citrus consuming nations have seen a diversification in the marketing of the South African citrus. The intensity of competition in the global market is reflected by the fluctuations in the market shares in different markets as well as the increase and fluctuations of fruit rejection rates in some lucrative markets such as America. A combination of challenging national environmental forces and stringent demand conditions negatively impact on revenues especially from markets characterised by price competitiveness. This study identified cost of production, foreign market support systems, adaptability, worker skills, challenges of management in an international environment and government policies such as labour and trade policies as some of the most influential obstacles to competitiveness. Some of the most competiveness-enhancing factors were market availability, market size, market information, market growth and the availability of research institutions. However, compliance with private standards still poses a challenge to the exporters. The different performance levels of the industry in various markets prove the dissimilarity of the demand conditions in the global market. These are supported by the negative influence associated with the foreign market support regimes as well as the challenges associated with compliance with private food safety standards. While market availability, market growth, market information and size were identified as enhancing competitiveness, the fluctuations and inconsistencies in the competitiveness of the industry in different foreign markets require more than finding markets. Resource allocation by both the government and the industry may need to take into account the off-setting of the national challenges and support of farmers faced with distorted and unfair international playing fields. Otherwise, market availability is not a challenge for the industry save meeting the specifications therewith as well as price competitiveness which is unattainable for the South African citrus producers faced with high production costs. For the purposes of further study, it is recommended that account should be taken of all the products marketed by the industry (including processed products such as fruit juices) in order to have a whole picture of the competitiveness of the industry in the international market. This study also proffers a new theoretical framework for the analysis of the business environment for the citrus industry and other agro-businesses. This framework takes into account the indispensability of the food safety standards and measures as well as the diversity of the global consumer and the non-negotiability of food trade for the sustenance of the growing population.
- Full Text:
- Date Issued: 2009
Pre-Service Teachers’ Perceptions about the Value of Teaching Practice Assessment as a Catalyst to the Improvement of Quality Model
- Authors: Bako, Yellow
- Date: 2020
- Subjects: Teaching -- Evaluation Effective teaching
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/17921 , vital:41978
- Description: Teaching Practice assessment is criticized for not promoting critical reflection and problem-solving thinking in pre-service teachers as expected. Pre-service teachers lack praxis: translating theoretical knowledge into authentic practice. Teaching Practice assessment is too traditional to offer authentic evaluation for life-long learning. Globally, Teaching Practice is the greatest academic process in training preservice teachers. However, there are concerns raised regarding what is regarded as inadequate teacher preparation, inconsistencies and subjectivity in Teaching Practice assessment, and misalignment between instructional theory and classroom practice have resulted in high demand for quality improvement of the Teaching Practice assessment framework. The research has adopted the post-positivism research paradigm, mixed methods research approach, and the QUAN-QUAL sequential explanatory research design. The population was all Post Graduate students at one university and all Diploma in Education students at on Teachers College in Zimbabwe. Data collection instruments used were: observations schedule, interviews, questionnaires, and documentary analysis. Results have shown that Teaching Practice assessment was of great value for academic, pedagogical, and teacher professional development. Subject content knowledge posed greater challenge to preservice teachers than pedagogical content knowledge during Teaching Practice assessment. School environment, accommodation, lack of material and financial resources, heavy workload, indiscipline, unexpected assessment visits, and contradictions by assessors were major factors that affected Teaching Practice assessment. Pre-service teachers preferred to be assessed by college-based to university-based assessors because they give them feedback for learning, they motivate, and they understand their plight, and they appear more professional in their conduct than university-based assessors. The study therefore suggests a framework for improving the quality of Teaching Practice that includes a balanced curriculum, intensified training on content knowledge and pedagogical content knowledge; a proper collaboration between college and university assessors; training in ICT, and more focused Teaching Practice workload, and the practice of reflective, authentic, and emancipatory assessment practices for sustainable development.
- Full Text:
- Date Issued: 2020
- Authors: Bako, Yellow
- Date: 2020
- Subjects: Teaching -- Evaluation Effective teaching
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/17921 , vital:41978
- Description: Teaching Practice assessment is criticized for not promoting critical reflection and problem-solving thinking in pre-service teachers as expected. Pre-service teachers lack praxis: translating theoretical knowledge into authentic practice. Teaching Practice assessment is too traditional to offer authentic evaluation for life-long learning. Globally, Teaching Practice is the greatest academic process in training preservice teachers. However, there are concerns raised regarding what is regarded as inadequate teacher preparation, inconsistencies and subjectivity in Teaching Practice assessment, and misalignment between instructional theory and classroom practice have resulted in high demand for quality improvement of the Teaching Practice assessment framework. The research has adopted the post-positivism research paradigm, mixed methods research approach, and the QUAN-QUAL sequential explanatory research design. The population was all Post Graduate students at one university and all Diploma in Education students at on Teachers College in Zimbabwe. Data collection instruments used were: observations schedule, interviews, questionnaires, and documentary analysis. Results have shown that Teaching Practice assessment was of great value for academic, pedagogical, and teacher professional development. Subject content knowledge posed greater challenge to preservice teachers than pedagogical content knowledge during Teaching Practice assessment. School environment, accommodation, lack of material and financial resources, heavy workload, indiscipline, unexpected assessment visits, and contradictions by assessors were major factors that affected Teaching Practice assessment. Pre-service teachers preferred to be assessed by college-based to university-based assessors because they give them feedback for learning, they motivate, and they understand their plight, and they appear more professional in their conduct than university-based assessors. The study therefore suggests a framework for improving the quality of Teaching Practice that includes a balanced curriculum, intensified training on content knowledge and pedagogical content knowledge; a proper collaboration between college and university assessors; training in ICT, and more focused Teaching Practice workload, and the practice of reflective, authentic, and emancipatory assessment practices for sustainable development.
- Full Text:
- Date Issued: 2020
Inter-individual variability and phenotypic plasticity : the effect of the environment on the biogeography, population structure, ecophysiology and reproduction of the sandhoppers Talorchestia capensis and Africorchestia quadrispinosa
- Authors: Baldanzi, Simone
- Date: 2014
- Subjects: Phenotypic plasticity -- Research -- Africa, Southern Talitridae -- Research -- Africa, Southern Amphipoda -- Research -- Africa, Southern Climatic changes -- Environmental aspects -- Africa, Southern Marine biology -- Africa, Southern Adaptation (Biology) -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5846 , http://hdl.handle.net/10962/d1011447
- Description: Climatic envelope models focus on the climatic variables affecting species or species assemblages, and are important tools to investigate the effect of climate change on their geographical ranges. These models have largely been proposed in order to make successful predictions on species‘ persistence, determining which variables are likely to induce range expansion, contraction, or shifting. More recent models, including the ability and the cost for individuals to respond promptly to an environmental stimulus, have revealed that species may express phenotypic plasticity able to induce adaptation to the new environment. Consequently, understanding how species evolve to a changing climate is fundamental. From this perspective, investigating intraspecific responses to an environmental variable may contribute to better understanding and prediction of the effect of climate change on the geographical range and evolution of species, particularly in the case of widespread species. In this context, the present study aimed at establishing how environmental variables (focussing mainly on temperature) may have contributed to shape the spatial distribution, physiology, reproductive biology and connectivity of two species of Southern African sandhoppers (Talorchestia capensis and Africorchestia quadrispinosa, Amphipoda, Talitridae). Most of the work was carried out on T. capensis, due to its widespread spatial distribution. A first investigation of the biogeography of T. capensis and A. quadrispinosa, revealed that, for both species, spatial patterns of abundance, size and sex ratio were not explained by the Abundant Centre Hypothesis (greater abundance at the core of a spatial range), but rather guided by bio-physical forces. Precisely, the abundance of sandhoppers was driven by the morphodynamic state of the beach, salinity and temperatures, with strong differentiation among sites that reflected local environmental conditions. In support of these findings, strong population structure in the genetics of T. capensis was found (three main groups) when investigating its phylogeography and genetic connectivity. Although such defined structure may suggests cryptic speciation, the concomitant within-population variation in the COX1 region of mtDNA, also highlighted the importance of individual genetic variability. High individual variability was also found in the response of T. capensis to temperature, both in its physiology (thermal plasticity) and its reproductive biology (maternal effects). Since temperature is one of the main variables affecting the coastal marine systems of southern Africa and the metabolism of animals in general, its effect on the physiology and reproduction of T. capensis was therefore investigated. Thermal responses to increasing/decreasing temperatures were assessed for separated populations of T. capensis. Individual variability was reported in the oxygen consumption of T. capensis in response to temperature (high variation around the means, especially for increasing temperatures). Among population differences in thermal sensitivity were significantly correlated with air temperature variability experienced over the past 23 years, highlighting the importance of historical temperature fluctuations to the current thermal physiology of these sandhoppers. Temperature also had an important effect on the reproductive plasticity of T. capensis. Different temperatures induced mothers to adjust the size of their offspring (i.e. egg size), with larger eggs produced at lower temperatures. Interestingly, females showed strongly significant among individual variation in the size of the eggs. Given the importance of understanding rapid responses of organisms to climate change and considering the fundamental role played by phenotypic plasticity in evolution, the overall study revealed the significance of individual plasticity and variability in response to the environment and highlighted its importance. Particularly, studying the thermal physiology of separated populations and understanding within population reproductive plasticity in response to temperature, helped to clarify how differences among individual responses have important consequences at the population level, possibly explaining the widespread distribution of T. capensis.
- Full Text:
- Date Issued: 2014
- Authors: Baldanzi, Simone
- Date: 2014
- Subjects: Phenotypic plasticity -- Research -- Africa, Southern Talitridae -- Research -- Africa, Southern Amphipoda -- Research -- Africa, Southern Climatic changes -- Environmental aspects -- Africa, Southern Marine biology -- Africa, Southern Adaptation (Biology) -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5846 , http://hdl.handle.net/10962/d1011447
- Description: Climatic envelope models focus on the climatic variables affecting species or species assemblages, and are important tools to investigate the effect of climate change on their geographical ranges. These models have largely been proposed in order to make successful predictions on species‘ persistence, determining which variables are likely to induce range expansion, contraction, or shifting. More recent models, including the ability and the cost for individuals to respond promptly to an environmental stimulus, have revealed that species may express phenotypic plasticity able to induce adaptation to the new environment. Consequently, understanding how species evolve to a changing climate is fundamental. From this perspective, investigating intraspecific responses to an environmental variable may contribute to better understanding and prediction of the effect of climate change on the geographical range and evolution of species, particularly in the case of widespread species. In this context, the present study aimed at establishing how environmental variables (focussing mainly on temperature) may have contributed to shape the spatial distribution, physiology, reproductive biology and connectivity of two species of Southern African sandhoppers (Talorchestia capensis and Africorchestia quadrispinosa, Amphipoda, Talitridae). Most of the work was carried out on T. capensis, due to its widespread spatial distribution. A first investigation of the biogeography of T. capensis and A. quadrispinosa, revealed that, for both species, spatial patterns of abundance, size and sex ratio were not explained by the Abundant Centre Hypothesis (greater abundance at the core of a spatial range), but rather guided by bio-physical forces. Precisely, the abundance of sandhoppers was driven by the morphodynamic state of the beach, salinity and temperatures, with strong differentiation among sites that reflected local environmental conditions. In support of these findings, strong population structure in the genetics of T. capensis was found (three main groups) when investigating its phylogeography and genetic connectivity. Although such defined structure may suggests cryptic speciation, the concomitant within-population variation in the COX1 region of mtDNA, also highlighted the importance of individual genetic variability. High individual variability was also found in the response of T. capensis to temperature, both in its physiology (thermal plasticity) and its reproductive biology (maternal effects). Since temperature is one of the main variables affecting the coastal marine systems of southern Africa and the metabolism of animals in general, its effect on the physiology and reproduction of T. capensis was therefore investigated. Thermal responses to increasing/decreasing temperatures were assessed for separated populations of T. capensis. Individual variability was reported in the oxygen consumption of T. capensis in response to temperature (high variation around the means, especially for increasing temperatures). Among population differences in thermal sensitivity were significantly correlated with air temperature variability experienced over the past 23 years, highlighting the importance of historical temperature fluctuations to the current thermal physiology of these sandhoppers. Temperature also had an important effect on the reproductive plasticity of T. capensis. Different temperatures induced mothers to adjust the size of their offspring (i.e. egg size), with larger eggs produced at lower temperatures. Interestingly, females showed strongly significant among individual variation in the size of the eggs. Given the importance of understanding rapid responses of organisms to climate change and considering the fundamental role played by phenotypic plasticity in evolution, the overall study revealed the significance of individual plasticity and variability in response to the environment and highlighted its importance. Particularly, studying the thermal physiology of separated populations and understanding within population reproductive plasticity in response to temperature, helped to clarify how differences among individual responses have important consequences at the population level, possibly explaining the widespread distribution of T. capensis.
- Full Text:
- Date Issued: 2014
Exploring transformative social learning and sustainability in community based irrigation scheme contexts in Mozambique
- Authors: Baloi, Aristides
- Date: 2017
- Subjects: Social learning -- Mozambique , Irrigation -- Social aspects -- Mozambique , Water resources development -- Mozambique , Sustainable agriculture -- Mozambique , Community development -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/50154 , vital:25963
- Description: This study set out to examine transformative social learning and sustainability in the context of community-based irrigation systems in Mozambique. These irrigation systems are socio-ecological in nature. The history of irrigation systems in Mozambique can be described in two periods: pre-Independence period (mainly the colonial period) and the post-Independence period from 1975 onwards. Most recently, the Mozambique Government has introduced a policy which supports community-based irrigation system implementation and management via irrigation associations in a move to support a shift from rain-fed farming practices to irrigation-supported farming practices amongst smallholder farmers. It is this shift in the object of activity that this study focusses on. It does this by studying learning process in the constituted irrigation associations, examining whether such learning is transformative and sustainability oriented or not, and how such learning can be further expanded and supported. Learning may occur in socio-ecological systems, but whether that learning enables transformation and sustainability of irrigation systems and the constituted associations is as yet under-explored in the Mozambique context and in the context of Education for Sustainable Development in southern Africa. The aim of this research was therefore to understand transformative social learning within the development of sustainable irrigation practices in the context of irrigation associations and new agrarian policy development in Mozambique. To examine transformative social learning in sustainable irrigation system practices (including management practices), the study worked with three research goals, which also formed phases of the study’s design: GOAL 1: Examine how and what transformative social learning has (or has not) emerged in existing activity systems to date (Phase 1: Activity System Analysis). GOAL 2: Examine how transformative social learning could emerge through expansive learning processes (Phase 2: Identification of contradictions and new solution modelling through Developmental Work Research and Change Laboratories). GOAL 3: Identify what opportunities exist for ongoing transformative social learning (Phase 3: Identification of absences and ongoing dialectical transformation possibilities). The study draws on theories of Social Learning, Transformative Learning and Cultural Historical Activity Theory’s (CHAT) expansive learning and formative interventionist research framework to develop insights into the learning processes. It works especially with third generation Cultural Historical Activity Theory which provides a theory of expansive social learning and collective transformative agency formation, which I deemed most appropriate for the need to understand the transformation of farmers’ activities in a collective formation such as an irrigation association. The study involved identification and examination of interacting activity systems, contradictions or dissonances in two case studies of community-based irrigation system development via the respective associations. It involved identifying existing learning, as well as engaging in formative intervention research to expand learning in two case study sites: namely the Macubulane and Massaca Irrigation Associations, located near Maputo, Mozambique in the Inkomati and Umbeluzi river basins. The Macubulane community practices a monocropping system of sugar cane plantations using sprinkler irrigation methods and the Massaca community practices a mixed cropping system growing vegetables using mainly gravity or furrow irrigation methods. The study uses a qualitative research approach and is underlaboured by Dialectical Critical Realism which allowed for a deeper probing of ontology and transformative praxis, and transformative learning. The study used methods which included in-depth interviews, change laboratory workshops, document analysis and focus group interviews with farmers and subjects in associated activity systems. Analysis involved activity system analysis, identification of contradictions, modeling of solutions, transformative agency analysis, as well as analysis of real and nominal absences and generative mechanisms as recommended in dialectical critical realism. I used inductive, abductive and retroductive modes of inference, relying on the latter to identify further potential for transformative learning. The study demonstrates that within the associations, transformative social learning is taking place as farmers seek to address problems and contradictions. This learning leads to the creation of new agency and capabilities by ensuring good yields and continuous improvement of management practices and social status. Learning operates through formal mediation in the irrigation system of workplace-based operation, maintenance and crop management practices (i.e. through workplace learning). Social learning occurs through collective engagement with the constraints that the association faces while applying new knowledge, introducing new technology, in the process of administration and planning of irrigation activities. Expansive learning is possible when mediated actively through formative interventions in change laboratory workshops. All three types of learning were found to be present and possible in the context of the two irrigation scheme contexts. The main study findings are that transformative social learning is a collective object-driven process in the context of a transforming object (from rain-fed to sustainable community-based irrigation scheme farming in this study), that can be explained from the level of generative mechanisms and associated real absences that shape nominal absences and contradictions within and between activity systems. These induce, and have potential to induce, transformative learning in irrigation systems, including the emergence of transformative agency via learning through workplace-based, wider social learning, and expansive learning interaction processes amongst subjects in interacting activity systems. Absenting absences is also crucial for extending the potential of transformative learning in irrigation associations. The study further shows how critical realism helps to interpret learning processes and how it strengthens the empirical findings obtained from qualitative analysis. A key outcome of the study is a model that frames conceptualisation of transformative social learning in irrigation systems. The model and the insights gained into farmers learning around the transformation of the object of activity explored in this study have implications for wider curriculum and policy development interventions. The study therefore also makes recommendations for curriculum development and policy implementation intervention. The curriculum development recommendations are not at the level of making recommendations for new courses only, but frame how the design of new courses should take into account the wider processes of learning and change associated with the transformation of an object of activity as articulated in the study. It recommends an approach that allows for in-field engagement with contradictions and the absenting of absences (a problem-based type of curriculum) that will also allow for conceptual development and understanding of the changing object of activity (i.e. community-based irrigation scheme practice and management). The main policy recommendation made from the study is to invest more in farmer support and farmers’ learning so that they can transition from rain-fed agriculture to sustainable irrigation scheme development and management via their associations. The research contributes to knowledge production on irrigation practices; considering that substantial understandings were generated through analysis of communal irrigation scheme practice and management and its implications, especially from a transformative learning perspective. As shown in this study, transformative social learning theories are still not well understood in the context of irrigation system development, and this study has contributed knowledge to this field. The study contributes towards understanding of sustainability learning in irrigation associations in terms of concepts and practices. The study offers a model for transformative social learning in irrigation scheme development and suggests an expanded curriculum for community-based irrigation association practice and management. Overall, the study contributes to an understanding of transformative, sustainability oriented learning processes as support for the emergence of community-based irrigation associations. Additionally, the study has added perspectives on how to frame transformative social learning from a CHAT and critical realist perspective in Education for Sustainable Development. The study also contributes to a growing body of scholarship in southern Africa which seeks to develop expansive, transformative social learning approaches in response to concerns experienced by communities who are reliant on natural resources and the environment for their livelihoods and well-being, and who are also seeking to emerge out of poverty.
- Full Text:
- Date Issued: 2017
- Authors: Baloi, Aristides
- Date: 2017
- Subjects: Social learning -- Mozambique , Irrigation -- Social aspects -- Mozambique , Water resources development -- Mozambique , Sustainable agriculture -- Mozambique , Community development -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/50154 , vital:25963
- Description: This study set out to examine transformative social learning and sustainability in the context of community-based irrigation systems in Mozambique. These irrigation systems are socio-ecological in nature. The history of irrigation systems in Mozambique can be described in two periods: pre-Independence period (mainly the colonial period) and the post-Independence period from 1975 onwards. Most recently, the Mozambique Government has introduced a policy which supports community-based irrigation system implementation and management via irrigation associations in a move to support a shift from rain-fed farming practices to irrigation-supported farming practices amongst smallholder farmers. It is this shift in the object of activity that this study focusses on. It does this by studying learning process in the constituted irrigation associations, examining whether such learning is transformative and sustainability oriented or not, and how such learning can be further expanded and supported. Learning may occur in socio-ecological systems, but whether that learning enables transformation and sustainability of irrigation systems and the constituted associations is as yet under-explored in the Mozambique context and in the context of Education for Sustainable Development in southern Africa. The aim of this research was therefore to understand transformative social learning within the development of sustainable irrigation practices in the context of irrigation associations and new agrarian policy development in Mozambique. To examine transformative social learning in sustainable irrigation system practices (including management practices), the study worked with three research goals, which also formed phases of the study’s design: GOAL 1: Examine how and what transformative social learning has (or has not) emerged in existing activity systems to date (Phase 1: Activity System Analysis). GOAL 2: Examine how transformative social learning could emerge through expansive learning processes (Phase 2: Identification of contradictions and new solution modelling through Developmental Work Research and Change Laboratories). GOAL 3: Identify what opportunities exist for ongoing transformative social learning (Phase 3: Identification of absences and ongoing dialectical transformation possibilities). The study draws on theories of Social Learning, Transformative Learning and Cultural Historical Activity Theory’s (CHAT) expansive learning and formative interventionist research framework to develop insights into the learning processes. It works especially with third generation Cultural Historical Activity Theory which provides a theory of expansive social learning and collective transformative agency formation, which I deemed most appropriate for the need to understand the transformation of farmers’ activities in a collective formation such as an irrigation association. The study involved identification and examination of interacting activity systems, contradictions or dissonances in two case studies of community-based irrigation system development via the respective associations. It involved identifying existing learning, as well as engaging in formative intervention research to expand learning in two case study sites: namely the Macubulane and Massaca Irrigation Associations, located near Maputo, Mozambique in the Inkomati and Umbeluzi river basins. The Macubulane community practices a monocropping system of sugar cane plantations using sprinkler irrigation methods and the Massaca community practices a mixed cropping system growing vegetables using mainly gravity or furrow irrigation methods. The study uses a qualitative research approach and is underlaboured by Dialectical Critical Realism which allowed for a deeper probing of ontology and transformative praxis, and transformative learning. The study used methods which included in-depth interviews, change laboratory workshops, document analysis and focus group interviews with farmers and subjects in associated activity systems. Analysis involved activity system analysis, identification of contradictions, modeling of solutions, transformative agency analysis, as well as analysis of real and nominal absences and generative mechanisms as recommended in dialectical critical realism. I used inductive, abductive and retroductive modes of inference, relying on the latter to identify further potential for transformative learning. The study demonstrates that within the associations, transformative social learning is taking place as farmers seek to address problems and contradictions. This learning leads to the creation of new agency and capabilities by ensuring good yields and continuous improvement of management practices and social status. Learning operates through formal mediation in the irrigation system of workplace-based operation, maintenance and crop management practices (i.e. through workplace learning). Social learning occurs through collective engagement with the constraints that the association faces while applying new knowledge, introducing new technology, in the process of administration and planning of irrigation activities. Expansive learning is possible when mediated actively through formative interventions in change laboratory workshops. All three types of learning were found to be present and possible in the context of the two irrigation scheme contexts. The main study findings are that transformative social learning is a collective object-driven process in the context of a transforming object (from rain-fed to sustainable community-based irrigation scheme farming in this study), that can be explained from the level of generative mechanisms and associated real absences that shape nominal absences and contradictions within and between activity systems. These induce, and have potential to induce, transformative learning in irrigation systems, including the emergence of transformative agency via learning through workplace-based, wider social learning, and expansive learning interaction processes amongst subjects in interacting activity systems. Absenting absences is also crucial for extending the potential of transformative learning in irrigation associations. The study further shows how critical realism helps to interpret learning processes and how it strengthens the empirical findings obtained from qualitative analysis. A key outcome of the study is a model that frames conceptualisation of transformative social learning in irrigation systems. The model and the insights gained into farmers learning around the transformation of the object of activity explored in this study have implications for wider curriculum and policy development interventions. The study therefore also makes recommendations for curriculum development and policy implementation intervention. The curriculum development recommendations are not at the level of making recommendations for new courses only, but frame how the design of new courses should take into account the wider processes of learning and change associated with the transformation of an object of activity as articulated in the study. It recommends an approach that allows for in-field engagement with contradictions and the absenting of absences (a problem-based type of curriculum) that will also allow for conceptual development and understanding of the changing object of activity (i.e. community-based irrigation scheme practice and management). The main policy recommendation made from the study is to invest more in farmer support and farmers’ learning so that they can transition from rain-fed agriculture to sustainable irrigation scheme development and management via their associations. The research contributes to knowledge production on irrigation practices; considering that substantial understandings were generated through analysis of communal irrigation scheme practice and management and its implications, especially from a transformative learning perspective. As shown in this study, transformative social learning theories are still not well understood in the context of irrigation system development, and this study has contributed knowledge to this field. The study contributes towards understanding of sustainability learning in irrigation associations in terms of concepts and practices. The study offers a model for transformative social learning in irrigation scheme development and suggests an expanded curriculum for community-based irrigation association practice and management. Overall, the study contributes to an understanding of transformative, sustainability oriented learning processes as support for the emergence of community-based irrigation associations. Additionally, the study has added perspectives on how to frame transformative social learning from a CHAT and critical realist perspective in Education for Sustainable Development. The study also contributes to a growing body of scholarship in southern Africa which seeks to develop expansive, transformative social learning approaches in response to concerns experienced by communities who are reliant on natural resources and the environment for their livelihoods and well-being, and who are also seeking to emerge out of poverty.
- Full Text:
- Date Issued: 2017
Investigation of the thermo-chemical behaviour of coal-algae agglomerates
- Authors: Baloyi, Hope
- Date: 2018
- Subjects: Biomass energy , Coal -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23913 , vital:30642
- Description: There is a growing research interest in the co-processing of biomass and coal, with the aim of addressing the negative attributes associated with the thermal processing of coal alone. Biomass feedstocks are regarded as a clean, renewable source, and the co-utilization of biomass feedstocks with coal is deemed to have a potential to reduce emission of pollutants (i.e. NOx and SOx) and volatile organic compounds (VOC’s). Moreover, biomass are thermally reactive and thus facilitate the conversion of coal during co-processing. Biomass material and coal are two autonomous fuel materials with different chemical characteristics and have a dissimilar thermal behaviour making it difficult to achieve chemical interaction between the two solid fuels to contribute to the formation of products. Coalgae® Technology developed at the Nelson Mandela University, involves the biological treatment of coal fines by adsorbing live microalgae biomass (in slurry form) onto waste coal fines to form coal-microalgae agglomerates. This new innovative approach seeks to integrate bio-based feedstock into coal thermal processing and to improve the utilization and thermal efficiency of coal fines as well as the interaction between the volatile components of biomass and coal during thermal processing (e.g. devolatilization), thereby overcoming some of the challenges that confront the co-processing of coal and biomass. Coal fines are low-ranked coals, generally characterized by high contents of sulphur, high ash yields, low calorific values and poor thermal reactivity, and these attributes limits the thermo-chemical processing of the coal fines. Therefore, this investigation was undertaken to assess the thermo-chemical behaviour of coal-microalgae agglomerates, formed by adsorbing live microalgae slurry at varying ratios onto coal fines. For this purpose, the effects of adsorbing microalgae at varying ratios on the chemical characteristics and thermal behaviour of coal fines under pyrolytic conditions were investigated. The primary aim was to assess whether the thermo-chemical behaviour of coal-microalgae agglomerates, formed by adsorption of live microalgae onto fine coal, is substantively modified compared to a simple additive model of the original coal and pre-dried microalgae biomass samples. Results obtained from the proximate analyses performed on an Eltra Thermo-gravimetric analyzer (TGA) thermostep, have shown that the adsorption of microalgae slurry onto coal fines does not possess greater influence in improving the yield of volatiles and ash in coal fines than can be expected from a simple additive model of the original raw materials. Based on the ultimate analyses results, it was found that the adsorption of microalgae slurry resulted in a systematic reduction in the sulphur content, a notable increase in the hydrogen and oxygen contents, however, no significant disparities were found between the measured ultimate properties of coal-microalgae agglomerates as compared to the theoretically-expected ultimate properties from a simple linear combination of parental coal and microalgae biomass. Assessment of the thermal behaviour of parental samples and coal-microalgae agglomerates involved the use non-isothermal (40-900ºC, 20 K/min) thermogravimetry under inert conditions. It was found that the adsorption of microalgae slurry onto coal fines resulted in an improved thermal reactivity of coal fines, although, did not affect the overall pyrolysis characteristics of the coal fines. Comparison of the thermal profiles (measured and calculated TG/DTG curves), revealed that the yield of volatile products during the pyrolysis of coal-microalgae blends do not exceed the expected volatile yields from a simple combination of coal and microalgae biomass. These results suggest that there was no positive or accelerative synergistic interaction between volatile components of adsorbed microalgae and coal fines during pyrolysis. Mild pyrolysis of raw coal and coal-microalgae performed in a fixed-bed reactor furnace (450ºC), resulted in improved yields of Fossil-Bio crude (FBC) oil (derived from coal-microalgae pyrolysis), at increased biomass ratio compared to coal tar. FBC Oil was found to contain relatively high contents of oxygen, hydrogen, and low sulphur content than coal tar. GC-MS analyses showed the presence of a heterocyclic compounds (i.e. Indole and 2, 6 dimethyl pyridine) in the FBC oil and these were not identified in the coal tar. Furthermore, high boiling compounds such as Flourene, pyrene and pentacosane were identified in the coal tar, however not identified in the FBC oil. Simulated distillation results showed notable differences between the FBC oil and coal tar in terms of the distribution of boiling point fractions particularly, high boing point components. Semi-devolatilized chars derived from coal-microalgae agglomerates showed substantial degree of decarboxylation and dehydrogenation compared to the coal chars.
- Full Text:
- Date Issued: 2018
- Authors: Baloyi, Hope
- Date: 2018
- Subjects: Biomass energy , Coal -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23913 , vital:30642
- Description: There is a growing research interest in the co-processing of biomass and coal, with the aim of addressing the negative attributes associated with the thermal processing of coal alone. Biomass feedstocks are regarded as a clean, renewable source, and the co-utilization of biomass feedstocks with coal is deemed to have a potential to reduce emission of pollutants (i.e. NOx and SOx) and volatile organic compounds (VOC’s). Moreover, biomass are thermally reactive and thus facilitate the conversion of coal during co-processing. Biomass material and coal are two autonomous fuel materials with different chemical characteristics and have a dissimilar thermal behaviour making it difficult to achieve chemical interaction between the two solid fuels to contribute to the formation of products. Coalgae® Technology developed at the Nelson Mandela University, involves the biological treatment of coal fines by adsorbing live microalgae biomass (in slurry form) onto waste coal fines to form coal-microalgae agglomerates. This new innovative approach seeks to integrate bio-based feedstock into coal thermal processing and to improve the utilization and thermal efficiency of coal fines as well as the interaction between the volatile components of biomass and coal during thermal processing (e.g. devolatilization), thereby overcoming some of the challenges that confront the co-processing of coal and biomass. Coal fines are low-ranked coals, generally characterized by high contents of sulphur, high ash yields, low calorific values and poor thermal reactivity, and these attributes limits the thermo-chemical processing of the coal fines. Therefore, this investigation was undertaken to assess the thermo-chemical behaviour of coal-microalgae agglomerates, formed by adsorbing live microalgae slurry at varying ratios onto coal fines. For this purpose, the effects of adsorbing microalgae at varying ratios on the chemical characteristics and thermal behaviour of coal fines under pyrolytic conditions were investigated. The primary aim was to assess whether the thermo-chemical behaviour of coal-microalgae agglomerates, formed by adsorption of live microalgae onto fine coal, is substantively modified compared to a simple additive model of the original coal and pre-dried microalgae biomass samples. Results obtained from the proximate analyses performed on an Eltra Thermo-gravimetric analyzer (TGA) thermostep, have shown that the adsorption of microalgae slurry onto coal fines does not possess greater influence in improving the yield of volatiles and ash in coal fines than can be expected from a simple additive model of the original raw materials. Based on the ultimate analyses results, it was found that the adsorption of microalgae slurry resulted in a systematic reduction in the sulphur content, a notable increase in the hydrogen and oxygen contents, however, no significant disparities were found between the measured ultimate properties of coal-microalgae agglomerates as compared to the theoretically-expected ultimate properties from a simple linear combination of parental coal and microalgae biomass. Assessment of the thermal behaviour of parental samples and coal-microalgae agglomerates involved the use non-isothermal (40-900ºC, 20 K/min) thermogravimetry under inert conditions. It was found that the adsorption of microalgae slurry onto coal fines resulted in an improved thermal reactivity of coal fines, although, did not affect the overall pyrolysis characteristics of the coal fines. Comparison of the thermal profiles (measured and calculated TG/DTG curves), revealed that the yield of volatile products during the pyrolysis of coal-microalgae blends do not exceed the expected volatile yields from a simple combination of coal and microalgae biomass. These results suggest that there was no positive or accelerative synergistic interaction between volatile components of adsorbed microalgae and coal fines during pyrolysis. Mild pyrolysis of raw coal and coal-microalgae performed in a fixed-bed reactor furnace (450ºC), resulted in improved yields of Fossil-Bio crude (FBC) oil (derived from coal-microalgae pyrolysis), at increased biomass ratio compared to coal tar. FBC Oil was found to contain relatively high contents of oxygen, hydrogen, and low sulphur content than coal tar. GC-MS analyses showed the presence of a heterocyclic compounds (i.e. Indole and 2, 6 dimethyl pyridine) in the FBC oil and these were not identified in the coal tar. Furthermore, high boiling compounds such as Flourene, pyrene and pentacosane were identified in the coal tar, however not identified in the FBC oil. Simulated distillation results showed notable differences between the FBC oil and coal tar in terms of the distribution of boiling point fractions particularly, high boing point components. Semi-devolatilized chars derived from coal-microalgae agglomerates showed substantial degree of decarboxylation and dehydrogenation compared to the coal chars.
- Full Text:
- Date Issued: 2018
Determinants of Type 2 diabetes mellitus among HIV/AIDS patients on antiretroviral drugs in the OR Tambo District, South Africa
- Authors: Bam, Nokwanda Edith
- Date: 2018
- Subjects: HIV/AIDS Diabetes mellitus (DM) -- Patients Antiretroviral drugs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD Health Sciences
- Identifier: http://hdl.handle.net/11260/1476 , vital:35976
- Description: Type 2 diabetes mellitus (DM) is a frequent adverse effect of antiretroviral drugs for those who are on ARVS. People with type 2 DM can suffer multiple complications that hinder the quality of life. In South Africa research has shown significant increase in neuropathy, heart and kidney diseases among patients living with type 2 DM and HIV/AIDS compared to DM without HIV. Accessed knowledge lacked consistency on the predictors of DM in HIV/AIDS patients with regards to the type of ARVS with higher risks of DM. Research needed to be done to find the determinants of type 2 DM in HIV/AIDS context. The purpose of this study was to describe the determinants of type 2 DM among HIV/AIDS patients on ARVS in the OR Tambo District, SA in order to develop intervention strategies to mitigate the long-term effects of type 2 DM. A quantitative research methodology using a case control retrospective study was used. A sample of 177 (33%) cases with HIV/AIDS and type 2 DM was selected using a one stage stratified sampling with allocation proportional to size of each stratum of the four sub-districts of OR Tambo District. Two non-diabetic patients with HIV/AIDS were selected as controls per case unpaired and totalled up to 354 (67%) controls. A self-administration questionnaire adopted from the WHO (2011) STEPwise surveillance tool for chronic diseases was used for data collection. Stata (standard version 13.0, Stata Corp., Lakeway Drive USA) was used for data management and analysis. Findings of the study revealed determinants of type 2 DM grouped as the socio-demographic determinants; tertiary education and marital status, levels of physical activities; lack of vigorous activity and sport, types of diets; high fruits and vegetables and healthy eating out at restaurants, arterial blood pressure; lack of routine BP check and known HPT and types of ARVS used in HIV/AIDS therapy. Compared with patients who received FDC, the risk of type 2 DM was 43 times and 22 higher when a tri-therapy regimen contained Ritonavir and Lopinavir respectively . The majority of DM patients (n=177) were diagnosed type 2 DM after ARVS at n=108 (61%). In managing the diabetic patients a shift from a single disease to multiple-chronic disease focus is required to mitigate the complex drug interactions that exist in the control of NCDs such as HIV/AIDS, DM, HPT and other long-term diseases. The HIV/AIDS and type 2 DM awareness and care intervention strategy is recommended as healthy lifestyle, monitoring of side effects and drug interactions, enhanced FDC roll out and elimination of unsafe ARVS to improve the health outcomes of type 2 DM patients in an HIV/AIDS context in OR Tambo District.
- Full Text:
- Date Issued: 2018
- Authors: Bam, Nokwanda Edith
- Date: 2018
- Subjects: HIV/AIDS Diabetes mellitus (DM) -- Patients Antiretroviral drugs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD Health Sciences
- Identifier: http://hdl.handle.net/11260/1476 , vital:35976
- Description: Type 2 diabetes mellitus (DM) is a frequent adverse effect of antiretroviral drugs for those who are on ARVS. People with type 2 DM can suffer multiple complications that hinder the quality of life. In South Africa research has shown significant increase in neuropathy, heart and kidney diseases among patients living with type 2 DM and HIV/AIDS compared to DM without HIV. Accessed knowledge lacked consistency on the predictors of DM in HIV/AIDS patients with regards to the type of ARVS with higher risks of DM. Research needed to be done to find the determinants of type 2 DM in HIV/AIDS context. The purpose of this study was to describe the determinants of type 2 DM among HIV/AIDS patients on ARVS in the OR Tambo District, SA in order to develop intervention strategies to mitigate the long-term effects of type 2 DM. A quantitative research methodology using a case control retrospective study was used. A sample of 177 (33%) cases with HIV/AIDS and type 2 DM was selected using a one stage stratified sampling with allocation proportional to size of each stratum of the four sub-districts of OR Tambo District. Two non-diabetic patients with HIV/AIDS were selected as controls per case unpaired and totalled up to 354 (67%) controls. A self-administration questionnaire adopted from the WHO (2011) STEPwise surveillance tool for chronic diseases was used for data collection. Stata (standard version 13.0, Stata Corp., Lakeway Drive USA) was used for data management and analysis. Findings of the study revealed determinants of type 2 DM grouped as the socio-demographic determinants; tertiary education and marital status, levels of physical activities; lack of vigorous activity and sport, types of diets; high fruits and vegetables and healthy eating out at restaurants, arterial blood pressure; lack of routine BP check and known HPT and types of ARVS used in HIV/AIDS therapy. Compared with patients who received FDC, the risk of type 2 DM was 43 times and 22 higher when a tri-therapy regimen contained Ritonavir and Lopinavir respectively . The majority of DM patients (n=177) were diagnosed type 2 DM after ARVS at n=108 (61%). In managing the diabetic patients a shift from a single disease to multiple-chronic disease focus is required to mitigate the complex drug interactions that exist in the control of NCDs such as HIV/AIDS, DM, HPT and other long-term diseases. The HIV/AIDS and type 2 DM awareness and care intervention strategy is recommended as healthy lifestyle, monitoring of side effects and drug interactions, enhanced FDC roll out and elimination of unsafe ARVS to improve the health outcomes of type 2 DM patients in an HIV/AIDS context in OR Tambo District.
- Full Text:
- Date Issued: 2018
Implementation of classroom action research in Zimbabwean teacher education colleges: implications for teacher education curriculum
- Authors: Banda, Wilson
- Date: 2016
- Subjects: Action research in education , Education -- Research , Curriculum planning
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/10604 , vital:35632
- Description: It was the purpose of this study to interrogate the implementation of classroom action research (CAR) in identified Zimbabwean teachers’ colleges to provide the basis for future policy directions and related day-to-day CAR practice. The study leaned on the progressive educationists’ stance that teaching is an intricate profession that has more to it than mere technical skills. Teaching is viewed as a lifelong profession that requires pre-service teachers to be capacitated with CAR skills and competencies to ensure that they systematically, intentionally and critically consider a myriad of learner related psychosocial factors in their tour of duty. In that way teachers are made to appreciate why they should teach the way they teach, without necessarily turning them into some kind of public intellectuals, philosophers or theorists. The study utilised the mixed methods research approach in tune with the adopted pragmatism paradigm. The research paradigm draws on the strengths of both empirical data and the theoretical sentiments drawn from the respondents. The study used the concurrent triangulation design, rooted in the post-positivist research paradigm that integrates concurrent procedures in the collection, analysis and interpretation of research data. It was guided by three theoretical frameworks, namely, the experiential learning theory, the curriculum implementation framework and the living educational theory. The theories have a strong bearing on reflective practice and they acknowledge the subjectivity of truth. The study’s purposive sample comprised of sixty-four teacher educators and seventy-six preservice teachers. Several research instruments were utilised to solicit the requisite CAR implementation quantitative and qualitative data. These were questionnaires, interview schedules, focus group discussions and documents. The Statistical Packages for Social Sciences were used to summarise the solicited data through graphical representations and related frequency tables depicting descriptive statistics such as range, mean and mode. Qualitative data were analysed using content analysis through emerging themes, iv related to the sub-research questions. The study established that although the bulk of the teacher educators had the requisite professional qualifications, maturity and experiential background, more curricular and organisational reconstruction was required to improve on the status quo. For instance, solicited data demonstrated that the lecturers’ appetite for educational research was low. Furthermore, the teacher educators’ CAR skills and competencies were compromised by the research component’s inadequate contact time. In addition, it was instituted that the teachers’ colleges produced student teachers who lacked sound grasp of the CAR process. The mediocrity was attributed to a series of teacher educator and student teacher factors which were exacerbated by several other organisational and administrative impediments. Overall, the study concluded that teacher educators were incapacitated to effectively deliver CAR, owing partly to the nature of teacher educator preparation they got and the watered down professional induction. It further revealed that it was wrong to assume that all lecturers had operational capacity to effectively teach and supervise CAR projects. Furthermore, the study recommended that the teacher educators’ capacity in CAR needs enhancement. Identified CAR implementation strategies need further reconstruction and enforcement.
- Full Text:
- Date Issued: 2016
- Authors: Banda, Wilson
- Date: 2016
- Subjects: Action research in education , Education -- Research , Curriculum planning
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/10604 , vital:35632
- Description: It was the purpose of this study to interrogate the implementation of classroom action research (CAR) in identified Zimbabwean teachers’ colleges to provide the basis for future policy directions and related day-to-day CAR practice. The study leaned on the progressive educationists’ stance that teaching is an intricate profession that has more to it than mere technical skills. Teaching is viewed as a lifelong profession that requires pre-service teachers to be capacitated with CAR skills and competencies to ensure that they systematically, intentionally and critically consider a myriad of learner related psychosocial factors in their tour of duty. In that way teachers are made to appreciate why they should teach the way they teach, without necessarily turning them into some kind of public intellectuals, philosophers or theorists. The study utilised the mixed methods research approach in tune with the adopted pragmatism paradigm. The research paradigm draws on the strengths of both empirical data and the theoretical sentiments drawn from the respondents. The study used the concurrent triangulation design, rooted in the post-positivist research paradigm that integrates concurrent procedures in the collection, analysis and interpretation of research data. It was guided by three theoretical frameworks, namely, the experiential learning theory, the curriculum implementation framework and the living educational theory. The theories have a strong bearing on reflective practice and they acknowledge the subjectivity of truth. The study’s purposive sample comprised of sixty-four teacher educators and seventy-six preservice teachers. Several research instruments were utilised to solicit the requisite CAR implementation quantitative and qualitative data. These were questionnaires, interview schedules, focus group discussions and documents. The Statistical Packages for Social Sciences were used to summarise the solicited data through graphical representations and related frequency tables depicting descriptive statistics such as range, mean and mode. Qualitative data were analysed using content analysis through emerging themes, iv related to the sub-research questions. The study established that although the bulk of the teacher educators had the requisite professional qualifications, maturity and experiential background, more curricular and organisational reconstruction was required to improve on the status quo. For instance, solicited data demonstrated that the lecturers’ appetite for educational research was low. Furthermore, the teacher educators’ CAR skills and competencies were compromised by the research component’s inadequate contact time. In addition, it was instituted that the teachers’ colleges produced student teachers who lacked sound grasp of the CAR process. The mediocrity was attributed to a series of teacher educator and student teacher factors which were exacerbated by several other organisational and administrative impediments. Overall, the study concluded that teacher educators were incapacitated to effectively deliver CAR, owing partly to the nature of teacher educator preparation they got and the watered down professional induction. It further revealed that it was wrong to assume that all lecturers had operational capacity to effectively teach and supervise CAR projects. Furthermore, the study recommended that the teacher educators’ capacity in CAR needs enhancement. Identified CAR implementation strategies need further reconstruction and enforcement.
- Full Text:
- Date Issued: 2016
Modelling parallel and distributed virtual reality systems for performance analysis and comparison
- Authors: Bangay, Shaun Douglas
- Date: 1997
- Subjects: Virtual reality Computer simulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4657 , http://hdl.handle.net/10962/d1006656
- Description: Most Virtual Reality systems employ some form of parallel processing, making use of multiple processors which are often distributed over large areas geographically, and which communicate via various forms of message passing. The approaches to parallel decomposition differ for each system, as do the performance implications of each approach. Previous comparisons have only identified and categorized the different approaches. None have examined the performance issues involved in the different parallel decompositions. Performance measurement for a Virtual Reality system differs from that of other parallel systems in that some measure of the delays involved with the interaction of the separate components is required, in addition to the measure of the throughput of the system. Existing performance analysis approaches are typically not well suited to providing both these measures. This thesis describes the development of a performance analysis technique that is able to provide measures of both interaction latency and cycle time for a model of a Virtual Reality system. This technique allows performance measures to be generated as symbolic expressions describing the relationships between the delays in the model. It automatically generates constraint regions, specifying the values of the system parameters for which performance characteristics change. The performance analysis technique shows strong agreement with values measured from implementation of three common decomposition strategies on two message passing architectures. The technique is successfully applied to a range of parallel decomposition strategies found in Parallel and Distributed Virtual Reality systems. For each system, the primary decomposition techniques are isolated and analysed to determine their performance characteristics. This analysis allows a comparison of the various decomposition techniques, and in many cases reveals trends in their behaviour that would have gone unnoticed with alternative analysis techniques. The work described in this thesis supports the Performance Analysis and Comparison of Parallel and Distributed Virtual Reality systems. In addition it acts as a reference, describing the performance characteristics of decomposition strategies used in Virtual Reality systems.
- Full Text:
- Date Issued: 1997
- Authors: Bangay, Shaun Douglas
- Date: 1997
- Subjects: Virtual reality Computer simulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4657 , http://hdl.handle.net/10962/d1006656
- Description: Most Virtual Reality systems employ some form of parallel processing, making use of multiple processors which are often distributed over large areas geographically, and which communicate via various forms of message passing. The approaches to parallel decomposition differ for each system, as do the performance implications of each approach. Previous comparisons have only identified and categorized the different approaches. None have examined the performance issues involved in the different parallel decompositions. Performance measurement for a Virtual Reality system differs from that of other parallel systems in that some measure of the delays involved with the interaction of the separate components is required, in addition to the measure of the throughput of the system. Existing performance analysis approaches are typically not well suited to providing both these measures. This thesis describes the development of a performance analysis technique that is able to provide measures of both interaction latency and cycle time for a model of a Virtual Reality system. This technique allows performance measures to be generated as symbolic expressions describing the relationships between the delays in the model. It automatically generates constraint regions, specifying the values of the system parameters for which performance characteristics change. The performance analysis technique shows strong agreement with values measured from implementation of three common decomposition strategies on two message passing architectures. The technique is successfully applied to a range of parallel decomposition strategies found in Parallel and Distributed Virtual Reality systems. For each system, the primary decomposition techniques are isolated and analysed to determine their performance characteristics. This analysis allows a comparison of the various decomposition techniques, and in many cases reveals trends in their behaviour that would have gone unnoticed with alternative analysis techniques. The work described in this thesis supports the Performance Analysis and Comparison of Parallel and Distributed Virtual Reality systems. In addition it acts as a reference, describing the performance characteristics of decomposition strategies used in Virtual Reality systems.
- Full Text:
- Date Issued: 1997
Nonlinear optical responses of phthalocyanines in the presence of nanomaterials or when embedded in polymeric materials
- Authors: Bankole, Owolabi Mutolib
- Date: 2017
- Subjects: Phthalocyanines , Phthalocyanines -- Optical properties , Alkynes , Triazoles , Nonlinear optics , Photochemistry , Complex compounds , Amines , Mercaptopyridine
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/45794 , vital:25548
- Description: This work describes the synthesis, photophysical and nonlinear optical characterizations of alkynyl Pcs (1, 2, 3, 8 and 9), 1,2,3-triazole ZnPc (4), mercaptopyridine Pcs (5, 6 and 7) and amino Pcs (10 and 11). Complexes 1, 2, 4, 7, 8, 9 and 11 were newly synthesized and characterized using techniques including 1H-NMR, MALDI-TOF, UV-visible spectrophotometry, FTIR and elemental analysis. The results of the characterizations were in good agreement with their molecular structures, and confirmed the purity of the new molecules. Complex 10 was covalently linked to pristine graphene (GQDs), nitrogen- doped (NGQDs), and sulfur-nitrogen co-doped (SNGQDs) graphene quantum dots; gold nanoparticles (AuNPs); poly(acrylic acid) (PAA); Fe3O4@Ag core-shell and Fe3O4- Ag hybrid nanoparticles via covalent bonding. Complex 11 was linked to Agx Auy alloy nanoparticles via NH2-Au and/or Au-S bonding, 2 and 3 were linked to gold nanoparticles (AuNPs) via clicked reactions. Evidence of successful conjugation of 2, 3, 10 and 11 to nanomaterials was revealed within the UV-vis, EDS, TEM, XRD and XPS spectra. Optical limiting (OL) responses of the samples were evaluated using open aperture Z-scan technique at 532 nm and 10 ns radiation in solution or when embedded in polymer mixtures. The analyses of the Z-scan data for the studied samples did fit to a two-photon absorption mechanism (2PA), but the Pcs and Pc-nanomaterial or polymer composites also possess the multi-photon absorption mechanisms aided by the triplet-triplet population to have reverse saturable absorption (RSA) occur. Phthalocyanines doped in polymer matrices showed larger nonlinear absorption coefficients (ßeff), third-order susceptibility (Im [x(3)]) and second-order hyperpolarizability (y), with an accompanying low intensity threshold (Ium) than in solution. Aggregation in DMSO negatively affected NLO behaviour of Pcs (8 as a case study) at low laser power, and improved at relatively higher laser power. Heavy atom-substituted Pcs (6) enhanced NLO and OL properties than lighter atoms such as 5 and 7. Direct relationship between enhanced photophysical properties and nonlinear effects favoured by excited triplet absorption of the 2, 3, 10 and 11 in presence of nanomaterials was established. Major factor responsible for the enhanced nonlinearities of 10 in the presence of NGQDs and SNGQDs were fully described and attributed to the surface defects caused by the presence of heteroatoms such as nitrogen and sulfur. The studies showed that phthalocyanines-nanomaterial composites were useful in applications such as optical switching, pulse compressor and laser pulse narrowing.
- Full Text:
- Date Issued: 2017
- Authors: Bankole, Owolabi Mutolib
- Date: 2017
- Subjects: Phthalocyanines , Phthalocyanines -- Optical properties , Alkynes , Triazoles , Nonlinear optics , Photochemistry , Complex compounds , Amines , Mercaptopyridine
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/45794 , vital:25548
- Description: This work describes the synthesis, photophysical and nonlinear optical characterizations of alkynyl Pcs (1, 2, 3, 8 and 9), 1,2,3-triazole ZnPc (4), mercaptopyridine Pcs (5, 6 and 7) and amino Pcs (10 and 11). Complexes 1, 2, 4, 7, 8, 9 and 11 were newly synthesized and characterized using techniques including 1H-NMR, MALDI-TOF, UV-visible spectrophotometry, FTIR and elemental analysis. The results of the characterizations were in good agreement with their molecular structures, and confirmed the purity of the new molecules. Complex 10 was covalently linked to pristine graphene (GQDs), nitrogen- doped (NGQDs), and sulfur-nitrogen co-doped (SNGQDs) graphene quantum dots; gold nanoparticles (AuNPs); poly(acrylic acid) (PAA); Fe3O4@Ag core-shell and Fe3O4- Ag hybrid nanoparticles via covalent bonding. Complex 11 was linked to Agx Auy alloy nanoparticles via NH2-Au and/or Au-S bonding, 2 and 3 were linked to gold nanoparticles (AuNPs) via clicked reactions. Evidence of successful conjugation of 2, 3, 10 and 11 to nanomaterials was revealed within the UV-vis, EDS, TEM, XRD and XPS spectra. Optical limiting (OL) responses of the samples were evaluated using open aperture Z-scan technique at 532 nm and 10 ns radiation in solution or when embedded in polymer mixtures. The analyses of the Z-scan data for the studied samples did fit to a two-photon absorption mechanism (2PA), but the Pcs and Pc-nanomaterial or polymer composites also possess the multi-photon absorption mechanisms aided by the triplet-triplet population to have reverse saturable absorption (RSA) occur. Phthalocyanines doped in polymer matrices showed larger nonlinear absorption coefficients (ßeff), third-order susceptibility (Im [x(3)]) and second-order hyperpolarizability (y), with an accompanying low intensity threshold (Ium) than in solution. Aggregation in DMSO negatively affected NLO behaviour of Pcs (8 as a case study) at low laser power, and improved at relatively higher laser power. Heavy atom-substituted Pcs (6) enhanced NLO and OL properties than lighter atoms such as 5 and 7. Direct relationship between enhanced photophysical properties and nonlinear effects favoured by excited triplet absorption of the 2, 3, 10 and 11 in presence of nanomaterials was established. Major factor responsible for the enhanced nonlinearities of 10 in the presence of NGQDs and SNGQDs were fully described and attributed to the surface defects caused by the presence of heteroatoms such as nitrogen and sulfur. The studies showed that phthalocyanines-nanomaterial composites were useful in applications such as optical switching, pulse compressor and laser pulse narrowing.
- Full Text:
- Date Issued: 2017
Neuropharmacological interactions in the rat pineal gland a study of antidepressant drugs
- Authors: Banoo, Shabir
- Date: 1992
- Subjects: Antidepressants -- Research , Pineal gland -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3744 , http://hdl.handle.net/10962/d1003222 , Antidepressants -- Research , Pineal gland -- Research
- Description: The rat pineal gland provides a convenient model for investigating nor adrenergic receptor neurotransmission and the effects of various drugs on these processes in health and disease. The effect of a variety of antidepressant drugs on rat pineal gland function following acute and chronic administration is described. Antidepressants from several different classes increase melatonin synthesis in rat pineal gland cultures when administered acutely. This effect appears to be mediated by noradrenaline acting on postsynaptic β-adrenoceptors. Activation of these receptors, in turn, activates the enzyme serotonin N-acetyltransferase via a cyclic adenosine monophosphate (cAMP) second messenger system. Serotonin N-acetyltransferase catalyses the rate-limiting conversion of serotonin to melatonin. Blockade of postsynaptic β-adrenoceptors prevents the antidepressant-induced increase in melatonin synthesis. The possibility that atypical antidepressants as well as those that selectively inhibit serotonin reuptake may increase melatonin synthesis via a β-adrenoceptor mechanism is discussed. In contrast, however, antidepressants from different classes have variable effects on rat pineal gland function when administered repeatedly. Chronic treatment with antidepressants that selectively inhibit noradrenaline reuptake appear to down-regulate the β-adrenoceptor system while, simultaneously, increasing melatonin output. Atypical antidepressants and those that selectively inhibit serotonin reuptake appear to be without these effects when administered repeatedly. The pineal gland of normal rats may therefore not represent a suitable model for evaluating the biochemical effects of chronic antidepressant treatment. In an attempt to investigatc pineal gland function in rats with "model depression" , antidepressants were administered to chronically reserpinized rats. Treatment with reserpine produced an increase in the density of pineal β-adrenoceptors. In addition, pineal cyclic AMP accumulation and N-acetyltransferase activity were increased in reserpinized rats following exogenous catecholamine stimulation. Reserpine, by depleting intraneuronal catecholamine stores, prevented the nocturnal induction of N-acetyltransferase activity and reduced the synthesis of melatonin in pineal gland cultures. A variety of antidepressants, irrespective of their acute pharmacological actions, reversed these effects when administered chronically to resepinized rats. Acute antidepressant administration was not associated with a reversal of the reserpine-induced effects. These findings provide additional evidence against the hypothesis that antidepressant drugs act by reducing noradrenergic neurotransmission and casts doubt on the importance of β-adrenoceptor down-regulation in the mechanism of antidepressant action. The possibility that the pineal gland of the reserpinized rat may represent an alternative model for evaluating antidepressant therapies is discussed.
- Full Text:
- Date Issued: 1992
- Authors: Banoo, Shabir
- Date: 1992
- Subjects: Antidepressants -- Research , Pineal gland -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3744 , http://hdl.handle.net/10962/d1003222 , Antidepressants -- Research , Pineal gland -- Research
- Description: The rat pineal gland provides a convenient model for investigating nor adrenergic receptor neurotransmission and the effects of various drugs on these processes in health and disease. The effect of a variety of antidepressant drugs on rat pineal gland function following acute and chronic administration is described. Antidepressants from several different classes increase melatonin synthesis in rat pineal gland cultures when administered acutely. This effect appears to be mediated by noradrenaline acting on postsynaptic β-adrenoceptors. Activation of these receptors, in turn, activates the enzyme serotonin N-acetyltransferase via a cyclic adenosine monophosphate (cAMP) second messenger system. Serotonin N-acetyltransferase catalyses the rate-limiting conversion of serotonin to melatonin. Blockade of postsynaptic β-adrenoceptors prevents the antidepressant-induced increase in melatonin synthesis. The possibility that atypical antidepressants as well as those that selectively inhibit serotonin reuptake may increase melatonin synthesis via a β-adrenoceptor mechanism is discussed. In contrast, however, antidepressants from different classes have variable effects on rat pineal gland function when administered repeatedly. Chronic treatment with antidepressants that selectively inhibit noradrenaline reuptake appear to down-regulate the β-adrenoceptor system while, simultaneously, increasing melatonin output. Atypical antidepressants and those that selectively inhibit serotonin reuptake appear to be without these effects when administered repeatedly. The pineal gland of normal rats may therefore not represent a suitable model for evaluating the biochemical effects of chronic antidepressant treatment. In an attempt to investigatc pineal gland function in rats with "model depression" , antidepressants were administered to chronically reserpinized rats. Treatment with reserpine produced an increase in the density of pineal β-adrenoceptors. In addition, pineal cyclic AMP accumulation and N-acetyltransferase activity were increased in reserpinized rats following exogenous catecholamine stimulation. Reserpine, by depleting intraneuronal catecholamine stores, prevented the nocturnal induction of N-acetyltransferase activity and reduced the synthesis of melatonin in pineal gland cultures. A variety of antidepressants, irrespective of their acute pharmacological actions, reversed these effects when administered chronically to resepinized rats. Acute antidepressant administration was not associated with a reversal of the reserpine-induced effects. These findings provide additional evidence against the hypothesis that antidepressant drugs act by reducing noradrenergic neurotransmission and casts doubt on the importance of β-adrenoceptor down-regulation in the mechanism of antidepressant action. The possibility that the pineal gland of the reserpinized rat may represent an alternative model for evaluating antidepressant therapies is discussed.
- Full Text:
- Date Issued: 1992
The development of a concept of psychological well-being
- Authors: Bar-On, Reuven
- Date: 1988
- Subjects: Mental health -- Psychological aspects Personality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2928 , http://hdl.handle.net/10962/d1002437
- Description: This thesis focuses on the development of an operational and theoretically eclectic concept of psychological well-being. A comprehensive research strategy was employed to examine various personality factors thought to be components of psychological health (i.e., the basis of the proposed concept). The general approach involved four major phases: (1) the clustering of various variables and identification of underlying key factors purported to be related to psychological health based on the writer's clinical experience and review of the mental health literature, (2) the formulation of an ~ priori concept of psychological well-being based on the operational definition of those factors, (3) the construction of an inventory designed to examine the proposed concept, and (4) the interpretation of the results and their implications for the development of the overall concept based on the examination of the factorial structure, validity and reliability of the inventory. The"a posteriori concept" evolved out of this process. The results of the present study indicate that the most valid and reliable factorial components of psychological well-being are self regard,interpersonal relationship, independence, problem-solving, assertiveness,reality testing, stress tolerance, self-actualization and happiness; social responsibility and flexibility emerged as questionable components of the a posteriori concept. The inventory which was designed to study the concept was successful in significantly differentiating various levels of psychological health. This way of conceptualizing and assessing psychological well-being has potential applicability for mental health practitioners and researchers.
- Full Text:
- Date Issued: 1988
- Authors: Bar-On, Reuven
- Date: 1988
- Subjects: Mental health -- Psychological aspects Personality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2928 , http://hdl.handle.net/10962/d1002437
- Description: This thesis focuses on the development of an operational and theoretically eclectic concept of psychological well-being. A comprehensive research strategy was employed to examine various personality factors thought to be components of psychological health (i.e., the basis of the proposed concept). The general approach involved four major phases: (1) the clustering of various variables and identification of underlying key factors purported to be related to psychological health based on the writer's clinical experience and review of the mental health literature, (2) the formulation of an ~ priori concept of psychological well-being based on the operational definition of those factors, (3) the construction of an inventory designed to examine the proposed concept, and (4) the interpretation of the results and their implications for the development of the overall concept based on the examination of the factorial structure, validity and reliability of the inventory. The"a posteriori concept" evolved out of this process. The results of the present study indicate that the most valid and reliable factorial components of psychological well-being are self regard,interpersonal relationship, independence, problem-solving, assertiveness,reality testing, stress tolerance, self-actualization and happiness; social responsibility and flexibility emerged as questionable components of the a posteriori concept. The inventory which was designed to study the concept was successful in significantly differentiating various levels of psychological health. This way of conceptualizing and assessing psychological well-being has potential applicability for mental health practitioners and researchers.
- Full Text:
- Date Issued: 1988
Financial development in the SADC: growth and cross-country spatial spill-over effects
- Authors: Bara, Alex
- Date: 2017
- Subjects: Economic development -- South Africa Economic assistance -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/14950 , vital:27943
- Description: This study was prompted by the prevailing imbalance in financial development across SADC countries, which is not consistent with the linkages and interconnectedness of financial systems of these economies. South Africa is the most financially developed country in Africa, yet it is surrounded by economies with relatively small and underdeveloped financial systems, contrary to the spatial proximity theory in finance. The study performed a number of empirical estimations in respect of the spatiality of financial development, motivated by the intention to assess the growth and spatial spill-over effects of financial development in SADC. The study provides new information in spatial spill-over dynamics of financial development, which could inform policy development particularly in view of the on-going financial integration in the SADC region. The study also contributes to regional economic development in SADC from a finance perspective. The analysis was performed using annual data for all the 15 SADC countries, spanning for the period 1985 to 2014. Using the Generalised Method of Moments approach, the study finds that financial development does not support economic growth in SADC. Financial reforms were found to be insufficient to drive growth. A bi-directional causality between financial development and economic growth was established with causality being strong when flowing from economic growth to financial development. The extended Aghion, Howitt and Mayer-Foulkes Model, estimated by an Autoregressive Distributive Lag approach, established that financial innovation has a positive relation to economic growth in SADC, particularly in the long-run. There is no causality, in either direction, between financial innovation and economic growth in both the short and long-run. The Spatial Durbin Model reveals a presence of positive spatial effects on financial development in the region and that proximity to South Africa yields consistent effects of spatial externality in money markets and inconsistent spatial externality in credit markets. The monetary union has no influence on spatial dynamics of financial development in SADC. The generalised impulse response analysis of a Bayesian VAR model indicate that shocks in South Africa’s financial sector has positive, but constrained and in some cases weak, financial spill-over effects on both economic growth and financial development of other SADC countries. The study established, using the Herfindahl-Hirschman Index, a high level of financial market concentration for SADC, cantered in South Africa, and a fair distribution when South Africa is excluded. Dynamic panel models established that financial market concentration reduces financial development in SADC. South Africa’s financial development has mixed and opposing effects on financial market concentration in SADC. The findings also show that international finance has a positive, but currently weak, effect on financial development in SADC and countries with international financial centres contribute more to financial development than countries without. Proximity to South Africa creates huge potential for increasing financial development in SADC through spill-overs and more benefits of spatial proximity are realised in the long-run. Given the strong spatial effects in money markets and significant positive spill-overs in credit markets in the region, countries closer to South Africa need to link their money and credit markets to the South African markets and possibly benchmark to the Rand so as to benefit from proximity and spill-overs from South Africa. The results also suggest that SADC countries need to capitalise on their proximity to South Africa to enhance financial development by promoting economic growth, financial innovation, opening and diversification of financial sectors and linkages to global financial markets. Financial innovation supports financial inclusion, cross-border flows of funds, remittances and trade in SADC and has effects of enabling integration with developed markets and facilitating economic activity. Opening financial sectors enhances diversification of financial systems, increases competition and efficiency. To enhance access to international finance, the study suggests the creation of information centres in South Africa with SADC countries as economic hinterlands, commercialisation of solutions to SADC countries financial challenges, financial integration and support for deepening of financial systems in these countries. Strengthening economic growth could also increase financial development given a strong demand-following causality. The major challenge, however, is that some of the SADC countries have underdeveloped and highly concentrated financial systems characterised by high financial intermediation inefficiencies, high financial exclusion, weak financial infrastructure and regulations. Consequently, countries suffer financial leakages, are not receptive to spatial externalities and financial spill-overs from South Africa and often generate financial spillbacks to South Africa. SADC countries should, however, first address the issue of financial exclusion, financial infrastructure and regulation as well as efficiency in the financial markets. The SADC countries need mechanisms to attract financial development from South Africa to benefit from positive spill-overs and instruments to deal with negative externalities of financial shocks in South Africa. Overall, there is potential for increased financial development in SADC by consolidating absorption of positive financial spill-overs and externalities of proximity to South Africa -particularly in the medium to long term. Heterogeneity among SADC countries and the varying levels of financial development, however, dictates that the region should promote financial integration in order to enhance development of underdeveloped financial systems through spatial spill-over gains.
- Full Text:
- Date Issued: 2017
- Authors: Bara, Alex
- Date: 2017
- Subjects: Economic development -- South Africa Economic assistance -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/14950 , vital:27943
- Description: This study was prompted by the prevailing imbalance in financial development across SADC countries, which is not consistent with the linkages and interconnectedness of financial systems of these economies. South Africa is the most financially developed country in Africa, yet it is surrounded by economies with relatively small and underdeveloped financial systems, contrary to the spatial proximity theory in finance. The study performed a number of empirical estimations in respect of the spatiality of financial development, motivated by the intention to assess the growth and spatial spill-over effects of financial development in SADC. The study provides new information in spatial spill-over dynamics of financial development, which could inform policy development particularly in view of the on-going financial integration in the SADC region. The study also contributes to regional economic development in SADC from a finance perspective. The analysis was performed using annual data for all the 15 SADC countries, spanning for the period 1985 to 2014. Using the Generalised Method of Moments approach, the study finds that financial development does not support economic growth in SADC. Financial reforms were found to be insufficient to drive growth. A bi-directional causality between financial development and economic growth was established with causality being strong when flowing from economic growth to financial development. The extended Aghion, Howitt and Mayer-Foulkes Model, estimated by an Autoregressive Distributive Lag approach, established that financial innovation has a positive relation to economic growth in SADC, particularly in the long-run. There is no causality, in either direction, between financial innovation and economic growth in both the short and long-run. The Spatial Durbin Model reveals a presence of positive spatial effects on financial development in the region and that proximity to South Africa yields consistent effects of spatial externality in money markets and inconsistent spatial externality in credit markets. The monetary union has no influence on spatial dynamics of financial development in SADC. The generalised impulse response analysis of a Bayesian VAR model indicate that shocks in South Africa’s financial sector has positive, but constrained and in some cases weak, financial spill-over effects on both economic growth and financial development of other SADC countries. The study established, using the Herfindahl-Hirschman Index, a high level of financial market concentration for SADC, cantered in South Africa, and a fair distribution when South Africa is excluded. Dynamic panel models established that financial market concentration reduces financial development in SADC. South Africa’s financial development has mixed and opposing effects on financial market concentration in SADC. The findings also show that international finance has a positive, but currently weak, effect on financial development in SADC and countries with international financial centres contribute more to financial development than countries without. Proximity to South Africa creates huge potential for increasing financial development in SADC through spill-overs and more benefits of spatial proximity are realised in the long-run. Given the strong spatial effects in money markets and significant positive spill-overs in credit markets in the region, countries closer to South Africa need to link their money and credit markets to the South African markets and possibly benchmark to the Rand so as to benefit from proximity and spill-overs from South Africa. The results also suggest that SADC countries need to capitalise on their proximity to South Africa to enhance financial development by promoting economic growth, financial innovation, opening and diversification of financial sectors and linkages to global financial markets. Financial innovation supports financial inclusion, cross-border flows of funds, remittances and trade in SADC and has effects of enabling integration with developed markets and facilitating economic activity. Opening financial sectors enhances diversification of financial systems, increases competition and efficiency. To enhance access to international finance, the study suggests the creation of information centres in South Africa with SADC countries as economic hinterlands, commercialisation of solutions to SADC countries financial challenges, financial integration and support for deepening of financial systems in these countries. Strengthening economic growth could also increase financial development given a strong demand-following causality. The major challenge, however, is that some of the SADC countries have underdeveloped and highly concentrated financial systems characterised by high financial intermediation inefficiencies, high financial exclusion, weak financial infrastructure and regulations. Consequently, countries suffer financial leakages, are not receptive to spatial externalities and financial spill-overs from South Africa and often generate financial spillbacks to South Africa. SADC countries should, however, first address the issue of financial exclusion, financial infrastructure and regulation as well as efficiency in the financial markets. The SADC countries need mechanisms to attract financial development from South Africa to benefit from positive spill-overs and instruments to deal with negative externalities of financial shocks in South Africa. Overall, there is potential for increased financial development in SADC by consolidating absorption of positive financial spill-overs and externalities of proximity to South Africa -particularly in the medium to long term. Heterogeneity among SADC countries and the varying levels of financial development, however, dictates that the region should promote financial integration in order to enhance development of underdeveloped financial systems through spatial spill-over gains.
- Full Text:
- Date Issued: 2017
Towards a community based conservation strategy for wetlands in Uganda
- Authors: Barakagira, Alex
- Date: 2018
- Subjects: Conservation of natural resources , Wetland conservation -- Uganda Wetlands -- Uganda -- Management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23902 , vital:30640
- Description: Conservation of natural resources in Uganda focuses primarily on protected areas, including savannah national parks, mainly for conserving big game and forests, for controlling the harvest of commercially valuable timber resources, with less concern for wetlands. Later, policies and legislation in Uganda favoured agricultural production rather than the conservation of wetlands, a situation that culminated in their degradation. In a bid to counter the effects of wetlands degradation, Wetland Management Agencies were created. These agencies excluded the input of members of the local communities who reside in the wetlands environs. Local communities were not consulted on matters concerning management and conservation strategies, a situation that may have escalated the problem of wetlands degradation. Local knowledge is needed for the effective management and conservation of the wetlands and it is essential that local communities are included in decision making. This research study is more of an initiative for providing information that may be essential for the formulation of a community based conservation strategy for wetlands in Uganda. The study aimed to identify and characterize activities carried out by members of the local communities in wetlands found in central and western Uganda that are responsible for their progressive degradation; to assess the performance of existing Wetlands Management Institutions towards protection and conservation of wetlands in Uganda; to ascertain whether the acts and policies that have been promulgated for the protection of wetlands in Uganda have been adhered to by members of the local communities and to evaluate three community based conservation case studies with two vastly different outcomes in order to come up with the community-based conservation principles Ugandan communities may need to adopt to achieve sustainable utilisation and conservation of wetland resources. To achieve the objectives stated above, the researcher used a multi-disciplinary methodology that required several areas of expertise and sources of information. Hence, to accomplish the study, primary sources of data that included quantitative and qualitative data were collected from the study participants by means of a questionnaire survey, key informant interviews and direct observations. Secondary sources of data centred on published Ugandan acts and policies; textbooks; case study articles and journal articles. The study revealed a host of activities in which members of the local community are involved that have led to the degradation of the wetlands in Uganda. These include but are not limited to crop cultivation, dairy farming and unsustainable wetland resource harvesting. A number of other reasons for the degradation of the wetlands include unclear ownership of the wetlands, unclear wetland boundaries and a lack of awareness of the indirect benefits wetlands provide for members of the local communities. The study disclosed that wetlands management institutions have not been effective in the protection and conservation of wetlands in Uganda, mainly due to political interference and inadequate funding for the institutions’ conservation activities. The acts and policies that were promulgated for the protection and conservation of wetlands have been selectively implemented in some places and in others completely ignored, culminating in the degradation of the wetlands. The study revealed that effective community based conservation of wetlands in Uganda includes: initiation of the planning, implementation, monitoring and evaluation of all wetlands activities being borne by members of the local community; government introducing alternative income-generating activities aimed to reduce over-reliance on wetland resources and education of the local communities regarding the community-based projects’ objectives in order to garner their support. Recommendations emanating from this study are that the Land Act should be amended to specify a particular land tenure system, preferably freehold, which may promote the conservation of wetlands in Uganda; fertilizers (organic) should be introduced in the study area to fertilize the uplands that have reportedly become infertile in order to reduce the pressure the local community members are exerting on the wetlands for agriculture; wetlands management institutions should be empowered financially and political interference in activities aimed at conservation of wetlands in Uganda must cease. There should be uniform implementation of the rules and regulations stipulated in the acts and policies for all members of the public concerning wetlands protection. Lastly, essential community based conservation principles, as stated above, need to be applied carefully and adhered to if effective implementation of community-based conservation of wetlands is to be achieved in Uganda.
- Full Text:
- Date Issued: 2018
- Authors: Barakagira, Alex
- Date: 2018
- Subjects: Conservation of natural resources , Wetland conservation -- Uganda Wetlands -- Uganda -- Management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23902 , vital:30640
- Description: Conservation of natural resources in Uganda focuses primarily on protected areas, including savannah national parks, mainly for conserving big game and forests, for controlling the harvest of commercially valuable timber resources, with less concern for wetlands. Later, policies and legislation in Uganda favoured agricultural production rather than the conservation of wetlands, a situation that culminated in their degradation. In a bid to counter the effects of wetlands degradation, Wetland Management Agencies were created. These agencies excluded the input of members of the local communities who reside in the wetlands environs. Local communities were not consulted on matters concerning management and conservation strategies, a situation that may have escalated the problem of wetlands degradation. Local knowledge is needed for the effective management and conservation of the wetlands and it is essential that local communities are included in decision making. This research study is more of an initiative for providing information that may be essential for the formulation of a community based conservation strategy for wetlands in Uganda. The study aimed to identify and characterize activities carried out by members of the local communities in wetlands found in central and western Uganda that are responsible for their progressive degradation; to assess the performance of existing Wetlands Management Institutions towards protection and conservation of wetlands in Uganda; to ascertain whether the acts and policies that have been promulgated for the protection of wetlands in Uganda have been adhered to by members of the local communities and to evaluate three community based conservation case studies with two vastly different outcomes in order to come up with the community-based conservation principles Ugandan communities may need to adopt to achieve sustainable utilisation and conservation of wetland resources. To achieve the objectives stated above, the researcher used a multi-disciplinary methodology that required several areas of expertise and sources of information. Hence, to accomplish the study, primary sources of data that included quantitative and qualitative data were collected from the study participants by means of a questionnaire survey, key informant interviews and direct observations. Secondary sources of data centred on published Ugandan acts and policies; textbooks; case study articles and journal articles. The study revealed a host of activities in which members of the local community are involved that have led to the degradation of the wetlands in Uganda. These include but are not limited to crop cultivation, dairy farming and unsustainable wetland resource harvesting. A number of other reasons for the degradation of the wetlands include unclear ownership of the wetlands, unclear wetland boundaries and a lack of awareness of the indirect benefits wetlands provide for members of the local communities. The study disclosed that wetlands management institutions have not been effective in the protection and conservation of wetlands in Uganda, mainly due to political interference and inadequate funding for the institutions’ conservation activities. The acts and policies that were promulgated for the protection and conservation of wetlands have been selectively implemented in some places and in others completely ignored, culminating in the degradation of the wetlands. The study revealed that effective community based conservation of wetlands in Uganda includes: initiation of the planning, implementation, monitoring and evaluation of all wetlands activities being borne by members of the local community; government introducing alternative income-generating activities aimed to reduce over-reliance on wetland resources and education of the local communities regarding the community-based projects’ objectives in order to garner their support. Recommendations emanating from this study are that the Land Act should be amended to specify a particular land tenure system, preferably freehold, which may promote the conservation of wetlands in Uganda; fertilizers (organic) should be introduced in the study area to fertilize the uplands that have reportedly become infertile in order to reduce the pressure the local community members are exerting on the wetlands for agriculture; wetlands management institutions should be empowered financially and political interference in activities aimed at conservation of wetlands in Uganda must cease. There should be uniform implementation of the rules and regulations stipulated in the acts and policies for all members of the public concerning wetlands protection. Lastly, essential community based conservation principles, as stated above, need to be applied carefully and adhered to if effective implementation of community-based conservation of wetlands is to be achieved in Uganda.
- Full Text:
- Date Issued: 2018
Modelling the hydrological responses to changes in land use and cover in the Malaba River Catchment, Eastern Uganda
- Authors: Barasa, Bernard
- Date: 2014
- Subjects: Hydrologic models -- Uganda , Runoff -- Uganda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10670 , http://hdl.handle.net/10948/d1020153
- Description: Hydrological responses vary from one catchment to another, depending on the nature of land use and cover changes. Modelling the hydrological responses to changes in land use and cover at different catchment spatial scales was the major focus of this study. This study assessed the hydrological responses attributed to changes in land use and extreme weather events resulting into increased sediment loading/concentration, rainfall-runoff generation/volume, streamflow fluctuation and modification of the river channel in the Malaba River Catchment, Eastern Uganda. The hydrological responses were assessed using hydrological models (IHACRES, SCS CN, and SHETRAN) to examine the effect of land use on soil physio-chemical properties susceptibility to rainfall-runoff generation and volume, frequency and severity of extreme weather events, changes in streamflow variations, sediment loading/concentration and river channel morphology. The preliminary study results showed that the frequency of extreme weather events reduced from 4-10 to 1-3 years over the catchment. The performance of the IHACRES model with a Nash-Sutcliffe Efficiency (NSE) of 0.89 showed that streamflow comparatively corresponded with the results obtained the drought indices in predicting the recorded events of severe drought (2005) and flood (1997). Changes in land use and cover types showed that the highest change in the gain of land was experienced from the agricultural land use (36.7 percent), and tropical forest (regeneration) (2.2 percent). The biggest losses in land were experienced in the wetlands (24.6 percent) and bushland and thickets (15.3 percent) land cover types. The SHETRAN model calibrated period had a NSE of 0.78 and 0.81 in the validation period showed satisfactory fits between the measured and simulated streamflow. The agricultural land use (crop growing) had a higher influence on the rainfall-runoff generation and increase in the streamflow than the tropical forest, and bushland cover types in the simulated period. Similarly, the curve number model estimated a comparatively higher surface rainfall-runoff volume generated from the agricultural land use (crop growing) (71,740 m3) than in the bushlands and thickets (42,872 m3) from a rainstorm followed by the tropical forest cover type. This was also reflected in the lower rates of saturated hydraulic conductivity from the agricultural land use (crop growing). The study also showed that human-induced sediment loading due to gold mining activities contributed a much higher impact on the concentration of suspended sediments and streamflow than sediments from rainfall-runoff from the sampled streams. The main contributor of human-induced sediments to the Malaba River were Nankuke River (130.6kg/annum), followed by Omanyi River (70.6kg/annum), and Nabewo River (66.8kg/annum). Human-induced sediment loading had a profound impact on the streamflow variations both in the dry and wet seasons from the sampled tributaries. Lastly, in regard to the effect of land use and cover types on the river channel morphology, tree plantation (cohesion=12, angle of internal friction=27) and bushland and thickets (cohesion=14, angle of internal friction=22) cover types had the most stable river banks compared to the wetland and agricultural land use and cover types that exhibited higher levels of sediment concentration.
- Full Text:
- Date Issued: 2014
- Authors: Barasa, Bernard
- Date: 2014
- Subjects: Hydrologic models -- Uganda , Runoff -- Uganda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10670 , http://hdl.handle.net/10948/d1020153
- Description: Hydrological responses vary from one catchment to another, depending on the nature of land use and cover changes. Modelling the hydrological responses to changes in land use and cover at different catchment spatial scales was the major focus of this study. This study assessed the hydrological responses attributed to changes in land use and extreme weather events resulting into increased sediment loading/concentration, rainfall-runoff generation/volume, streamflow fluctuation and modification of the river channel in the Malaba River Catchment, Eastern Uganda. The hydrological responses were assessed using hydrological models (IHACRES, SCS CN, and SHETRAN) to examine the effect of land use on soil physio-chemical properties susceptibility to rainfall-runoff generation and volume, frequency and severity of extreme weather events, changes in streamflow variations, sediment loading/concentration and river channel morphology. The preliminary study results showed that the frequency of extreme weather events reduced from 4-10 to 1-3 years over the catchment. The performance of the IHACRES model with a Nash-Sutcliffe Efficiency (NSE) of 0.89 showed that streamflow comparatively corresponded with the results obtained the drought indices in predicting the recorded events of severe drought (2005) and flood (1997). Changes in land use and cover types showed that the highest change in the gain of land was experienced from the agricultural land use (36.7 percent), and tropical forest (regeneration) (2.2 percent). The biggest losses in land were experienced in the wetlands (24.6 percent) and bushland and thickets (15.3 percent) land cover types. The SHETRAN model calibrated period had a NSE of 0.78 and 0.81 in the validation period showed satisfactory fits between the measured and simulated streamflow. The agricultural land use (crop growing) had a higher influence on the rainfall-runoff generation and increase in the streamflow than the tropical forest, and bushland cover types in the simulated period. Similarly, the curve number model estimated a comparatively higher surface rainfall-runoff volume generated from the agricultural land use (crop growing) (71,740 m3) than in the bushlands and thickets (42,872 m3) from a rainstorm followed by the tropical forest cover type. This was also reflected in the lower rates of saturated hydraulic conductivity from the agricultural land use (crop growing). The study also showed that human-induced sediment loading due to gold mining activities contributed a much higher impact on the concentration of suspended sediments and streamflow than sediments from rainfall-runoff from the sampled streams. The main contributor of human-induced sediments to the Malaba River were Nankuke River (130.6kg/annum), followed by Omanyi River (70.6kg/annum), and Nabewo River (66.8kg/annum). Human-induced sediment loading had a profound impact on the streamflow variations both in the dry and wet seasons from the sampled tributaries. Lastly, in regard to the effect of land use and cover types on the river channel morphology, tree plantation (cohesion=12, angle of internal friction=27) and bushland and thickets (cohesion=14, angle of internal friction=22) cover types had the most stable river banks compared to the wetland and agricultural land use and cover types that exhibited higher levels of sediment concentration.
- Full Text:
- Date Issued: 2014
Systematics, morphology, phylogeny and historical biogeography of the Mayfly family Prosopistomatidae (Ephemeroptera: Insecta) of the world
- Barber-James, Helen Margaret
- Authors: Barber-James, Helen Margaret
- Date: 2011
- Subjects: Mayflies Mayflies -- Classification Mayflies -- Morphology Mayflies -- Phylogeny Mayflies -- Geographical distribution Ephemeridae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5785 , http://hdl.handle.net/10962/d1005473
- Description: The diversity, classification and historical biogeography of the mayfly family Prosopistomatidae are explored. First, the higher classification of the Ephemeroptera is reviewed, focussing on the phylogenetic placement of the Prosopistomatidae relative to other mayfly families. All relevant literature from 1762 to 2010 is synthesized. Baetiscidae are established as the probable sister lineage of Prosopistomatidae, the two constituting the superfamily Baetiscoidea. Next, qualitative morphological variation within the Prosopistomatidae is reviewed and revised, emphasizing nymphs because imaginal specimens are few. The labium and associated structures and the hypopharynx of nymphs, and the highly-derived wing venation of the imaginal stages, are re-interpreted. The structure of the male tarsal claws changes considerably between subimago and imago, which, together with deeply scalloped ridges on male imaginal forelegs and unusual pits on the female thorax, are interpreted as providing an unusual mating mechanism. These structures provide morphological characters for species definition and phylogenetic analyses. Two approaches to species delimitation are explored. First, morphometric variation is analysed using Principal Component Analysis, revealing groupings that can be interpreted as species, although there is some overlap between them. Discriminant Function Analysis shows that head width and carapace shape have the most value in identifying nymphs of different species. The carapace of Prosopistoma nymphs is shown to grow allometrically and gradually, in contrast with that of Baetisca, indicating a difference in early ontogeny. Second, an Artificial Neural Network algorithm applied to nymphal morphological characters accurately identified species. This computer-driven artificial intelligence method has power to provide future easy-to-use electronic identification aids. Phylogenetic analysis of nymphal morphology using the parsimony method shows two clades of Prosopistomatidae, one sharing characters with the type species, Prosopistoma variegatum and the other predominating in Africa, although also occurring in Asia; these clades are named the “P. variegatum” and “African” clades, respectively. Parsimony analysis of adult morphology supports these two clades, but supertree analysis obscures the relationships, nesting the “P. variegatum” lineage within the other clade. Preliminary molecular phylogenetic analysis of the 16S rRNA, (mitochondrial) 18S rRNA and Histone-3 genes using Bayesian Inference methods does not support the two clades shown by morphology. Instead, there is a strong relationship between the European species and one African species, with the single Asian representative being most distantly related. These results are limited by lack of fresh material, patchy taxon sampling, and problems with finding suitable primers. A molecular clock program, BEAST, calibrated using fossils, suggests divergence times for the oldest crown-group Prosopistoma clade, represented by the Asian P. wouterae, of about 131 Ma, with the youngest species, the African P. crassi, of 1.21 Ma. Stem-group relationships are analysed using parsimony analysis, focussing on wing characters of the Baetiscoidea, other extant mayfly lineages, and extinct stem-group lineages. This suggests that the Baetiscoidea diverged from main-line Ephemeroptera earlier than any other extant mayfly lineage. This approach expands upon ideas hinted at by earlier scientists. Finally, historical biogeographical analysis of the distribution of known Baetiscoidea s.s. stem-group fossils implies a once Pangean distribution of the lineage. Changing palaeo-climate, catastrophic extinction events and plate tectonic movements in relation to the distribution of crown-group species are reviewed. Other approaches to historical biogeography that build on both morphological and molecular phylogenies are used to interpret disperalist and vacarianist arguments. Distribution patterns of eight unrelated freshwater organisms which share a similar distribution pattern are compared, assuming that shared patterns indicate similar historic biogeographic processes. The distribution of recent Prosopistoma species is seen to be the product of evolution resulting from both vicariance and dispersal. In conclusion, this thesis encompasses a variety of disciplines. It successfully recognises new characters and distinguishes previously unknown species. It uses new approaches to delimiting species and known methods to determine phylogeny from several angles. The analysis of stem-group relationships offers an insight into possible early lineage splitting within Ephemeroptera. Interpretation of historical biogeography allows for both a Gondwanan origin of Prosopistomatidae, with rafting of species on the Deccan plate to Asia, and for subsequent dispersal from Asia down to Australia and across to Europe, and possibly back to Africa.
- Full Text:
- Date Issued: 2011
- Authors: Barber-James, Helen Margaret
- Date: 2011
- Subjects: Mayflies Mayflies -- Classification Mayflies -- Morphology Mayflies -- Phylogeny Mayflies -- Geographical distribution Ephemeridae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5785 , http://hdl.handle.net/10962/d1005473
- Description: The diversity, classification and historical biogeography of the mayfly family Prosopistomatidae are explored. First, the higher classification of the Ephemeroptera is reviewed, focussing on the phylogenetic placement of the Prosopistomatidae relative to other mayfly families. All relevant literature from 1762 to 2010 is synthesized. Baetiscidae are established as the probable sister lineage of Prosopistomatidae, the two constituting the superfamily Baetiscoidea. Next, qualitative morphological variation within the Prosopistomatidae is reviewed and revised, emphasizing nymphs because imaginal specimens are few. The labium and associated structures and the hypopharynx of nymphs, and the highly-derived wing venation of the imaginal stages, are re-interpreted. The structure of the male tarsal claws changes considerably between subimago and imago, which, together with deeply scalloped ridges on male imaginal forelegs and unusual pits on the female thorax, are interpreted as providing an unusual mating mechanism. These structures provide morphological characters for species definition and phylogenetic analyses. Two approaches to species delimitation are explored. First, morphometric variation is analysed using Principal Component Analysis, revealing groupings that can be interpreted as species, although there is some overlap between them. Discriminant Function Analysis shows that head width and carapace shape have the most value in identifying nymphs of different species. The carapace of Prosopistoma nymphs is shown to grow allometrically and gradually, in contrast with that of Baetisca, indicating a difference in early ontogeny. Second, an Artificial Neural Network algorithm applied to nymphal morphological characters accurately identified species. This computer-driven artificial intelligence method has power to provide future easy-to-use electronic identification aids. Phylogenetic analysis of nymphal morphology using the parsimony method shows two clades of Prosopistomatidae, one sharing characters with the type species, Prosopistoma variegatum and the other predominating in Africa, although also occurring in Asia; these clades are named the “P. variegatum” and “African” clades, respectively. Parsimony analysis of adult morphology supports these two clades, but supertree analysis obscures the relationships, nesting the “P. variegatum” lineage within the other clade. Preliminary molecular phylogenetic analysis of the 16S rRNA, (mitochondrial) 18S rRNA and Histone-3 genes using Bayesian Inference methods does not support the two clades shown by morphology. Instead, there is a strong relationship between the European species and one African species, with the single Asian representative being most distantly related. These results are limited by lack of fresh material, patchy taxon sampling, and problems with finding suitable primers. A molecular clock program, BEAST, calibrated using fossils, suggests divergence times for the oldest crown-group Prosopistoma clade, represented by the Asian P. wouterae, of about 131 Ma, with the youngest species, the African P. crassi, of 1.21 Ma. Stem-group relationships are analysed using parsimony analysis, focussing on wing characters of the Baetiscoidea, other extant mayfly lineages, and extinct stem-group lineages. This suggests that the Baetiscoidea diverged from main-line Ephemeroptera earlier than any other extant mayfly lineage. This approach expands upon ideas hinted at by earlier scientists. Finally, historical biogeographical analysis of the distribution of known Baetiscoidea s.s. stem-group fossils implies a once Pangean distribution of the lineage. Changing palaeo-climate, catastrophic extinction events and plate tectonic movements in relation to the distribution of crown-group species are reviewed. Other approaches to historical biogeography that build on both morphological and molecular phylogenies are used to interpret disperalist and vacarianist arguments. Distribution patterns of eight unrelated freshwater organisms which share a similar distribution pattern are compared, assuming that shared patterns indicate similar historic biogeographic processes. The distribution of recent Prosopistoma species is seen to be the product of evolution resulting from both vicariance and dispersal. In conclusion, this thesis encompasses a variety of disciplines. It successfully recognises new characters and distinguishes previously unknown species. It uses new approaches to delimiting species and known methods to determine phylogeny from several angles. The analysis of stem-group relationships offers an insight into possible early lineage splitting within Ephemeroptera. Interpretation of historical biogeography allows for both a Gondwanan origin of Prosopistomatidae, with rafting of species on the Deccan plate to Asia, and for subsequent dispersal from Asia down to Australia and across to Europe, and possibly back to Africa.
- Full Text:
- Date Issued: 2011
An investigation into Grade R teachers' experiences of implementing numeracy in Grade R
- Authors: Barnard, Elna
- Date: 2011
- Subjects: Teachers -- South Africa -- Attitudes Numeracy -- Study and teaching (Elementary) -- South Africa Teachers -- Training of -- South Africa Mathematics teachers -- In-service training -- South Africa Early childhood education -- South Africa -- History Early childhood education -- South Africa -- Political aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1855 , http://hdl.handle.net/10962/d1004529
- Description: This research study investigates how selected Grade R teachers implement numeracy in their classrooms, based on their experiences, personal beliefs and perceptions. This study adopts the view that a teacher's practice is not only informed on what she believes about her learners, but also on how she organises her classroom environment and her own teaching practice. However, the teacher cannot be divorced from the political and historical background of Early Childhood Development (ECD), as these factors have an impact on her numeracy implementation. Integrated in this research study is thus not only a comprehensive historical analysis of the historical and political background of ECD, but also an in-depth look at the complex curriculum road the Grade R teacher had to travel over the past twelve years. The aim of this case study is to understand and describe what is happening in Grade R classrooms when numeracy is implemented, as well as identifying possible barriers which Grade R teachers may experience in implementing numeracy. The author utilized an adapted Interactive Qualitative Analysis Framework to explore Grade R teachers' views and experiences. Open-ended focus group interviews were used to develop a framework for individual interviews. This interview framework guided the data collection of nine audio-video tapes of classroom activities and nine semi-structured individual interviews. Analysis of the individual interviews revealed each teacher's understanding as well as her perceptions and needs regarding the implementation of numeracy in her classroom. The transcriptions of the individual interviews were compared to the audio-video tapes of what happened in each classroom. This was done in order to determine whether the teachers' practices were consistent with what they said in the interviews. Paradoxes and inconsistencies were documented. The historical and political analysis of ECD illustrates the complex development of ECD in South Africa over the last few decades. It therefore also highlights and brings to the fore the complex journey that Grade R teachers had to navigate in adapting their practice to ever changing curriculum requirements. The empirical results show that there are inconsistencies between what selected teachers know and believe, and what they are implementing. However, "silent themes" which did not come to the fore in the focus group or individual interviews, were identified in the audiovideo tapes of classroom activities. Also, many "silent themes" indicate that there are numerous concerns, such as lack of proficiency in bridging the gap between theory and practice, regarding the implementation of numeracy in Grade R. It was found that many of the selected Grade R teachers struggle to implement numeracy in their classrooms, as they lack the skills and support to teach numeracy in a Grade R context.
- Full Text:
- Date Issued: 2011
- Authors: Barnard, Elna
- Date: 2011
- Subjects: Teachers -- South Africa -- Attitudes Numeracy -- Study and teaching (Elementary) -- South Africa Teachers -- Training of -- South Africa Mathematics teachers -- In-service training -- South Africa Early childhood education -- South Africa -- History Early childhood education -- South Africa -- Political aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1855 , http://hdl.handle.net/10962/d1004529
- Description: This research study investigates how selected Grade R teachers implement numeracy in their classrooms, based on their experiences, personal beliefs and perceptions. This study adopts the view that a teacher's practice is not only informed on what she believes about her learners, but also on how she organises her classroom environment and her own teaching practice. However, the teacher cannot be divorced from the political and historical background of Early Childhood Development (ECD), as these factors have an impact on her numeracy implementation. Integrated in this research study is thus not only a comprehensive historical analysis of the historical and political background of ECD, but also an in-depth look at the complex curriculum road the Grade R teacher had to travel over the past twelve years. The aim of this case study is to understand and describe what is happening in Grade R classrooms when numeracy is implemented, as well as identifying possible barriers which Grade R teachers may experience in implementing numeracy. The author utilized an adapted Interactive Qualitative Analysis Framework to explore Grade R teachers' views and experiences. Open-ended focus group interviews were used to develop a framework for individual interviews. This interview framework guided the data collection of nine audio-video tapes of classroom activities and nine semi-structured individual interviews. Analysis of the individual interviews revealed each teacher's understanding as well as her perceptions and needs regarding the implementation of numeracy in her classroom. The transcriptions of the individual interviews were compared to the audio-video tapes of what happened in each classroom. This was done in order to determine whether the teachers' practices were consistent with what they said in the interviews. Paradoxes and inconsistencies were documented. The historical and political analysis of ECD illustrates the complex development of ECD in South Africa over the last few decades. It therefore also highlights and brings to the fore the complex journey that Grade R teachers had to navigate in adapting their practice to ever changing curriculum requirements. The empirical results show that there are inconsistencies between what selected teachers know and believe, and what they are implementing. However, "silent themes" which did not come to the fore in the focus group or individual interviews, were identified in the audiovideo tapes of classroom activities. Also, many "silent themes" indicate that there are numerous concerns, such as lack of proficiency in bridging the gap between theory and practice, regarding the implementation of numeracy in Grade R. It was found that many of the selected Grade R teachers struggle to implement numeracy in their classrooms, as they lack the skills and support to teach numeracy in a Grade R context.
- Full Text:
- Date Issued: 2011