Case study : using visual representations to enhance conceptual knowledge of division in mathematics
- Authors: Joel, Linea Beautty
- Date: 2013
- Subjects: Mathematics -- Study and teaching , Visual learning , Division -- Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1992 , http://hdl.handle.net/10962/d1013356
- Description: Literature emphasizes how important it is that procedural and conceptual knowledge of mathematics should be learned in integration. Yet, generally, the learning and teaching in mathematics classrooms relies heavily on isolated procedures. This study aims to improve teaching and learning of partitive and quotitive division, moving away from isolated procedural knowledge to that of procedures with their underlying concepts through the use of manipulatives, visual representation and questioning. Learning and teaching lessons were designed to teach partitive and quotitive division both procedurally and conceptually. The study explored the roles these manipulatives, visual representations and questioning played toward the conceptual learning of partitive and quotitive division. It was found that manipulatives and iconic visualization enhanced learning, and this could be achieved through scaffolding using a questioning approach. It was concluded that manipulatives and iconic visualization need to be properly planned and used, and integrated with questioning to achieve success in the learning of procedural and conceptual knowledge.
- Full Text:
Case study : using visual representations to enhance conceptual knowledge of division in mathematics
- Authors: Joel, Linea Beautty
- Date: 2013
- Subjects: Mathematics -- Study and teaching , Visual learning , Division -- Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1992 , http://hdl.handle.net/10962/d1013356
- Description: Literature emphasizes how important it is that procedural and conceptual knowledge of mathematics should be learned in integration. Yet, generally, the learning and teaching in mathematics classrooms relies heavily on isolated procedures. This study aims to improve teaching and learning of partitive and quotitive division, moving away from isolated procedural knowledge to that of procedures with their underlying concepts through the use of manipulatives, visual representation and questioning. Learning and teaching lessons were designed to teach partitive and quotitive division both procedurally and conceptually. The study explored the roles these manipulatives, visual representations and questioning played toward the conceptual learning of partitive and quotitive division. It was found that manipulatives and iconic visualization enhanced learning, and this could be achieved through scaffolding using a questioning approach. It was concluded that manipulatives and iconic visualization need to be properly planned and used, and integrated with questioning to achieve success in the learning of procedural and conceptual knowledge.
- Full Text:
Changes in muscle recruitment, functional strength and ratings of perceived effort during an 8-over bowling spell: impact on performance
- Authors: Barford, Gareth Charles
- Date: 2013
- Subjects: Cricket -- Bowling , Sports -- Physiological aspects , Muscles -- Wounds and injuries , Fatigue , Physical fitness , Cricket injuries
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5102 , http://hdl.handle.net/10962/d1003926 , Cricket -- Bowling , Sports -- Physiological aspects , Muscles -- Wounds and injuries , Fatigue , Physical fitness , Cricket injuries
- Description: Background: The musculoskeletal demands placed on the lower limb musculature of fast bowlers over time have not received much attention. In particular, measures of muscle recruitment changes have, to the author’s knowledge, not been considered. Objective: The present study, therefore sought to establish any associations between an eight over, simulated fast bowling spell, and muscle activation patterns, power output, perceptual demands, and changes in performance. This will enable improvements in the development of training programmes. Methods: Players’ were required to attend two sessions in total. The purpose of the initial session was to collect specific demographic, anthropometric and physiological data and injury history information from each player. In addition, this first session allowed for habituation with the treadmill, the jump meter and all other equipment involved in experimentation. The second testing session involved electrode attachment sites being identified on player’s dominant leg. The areas were then shaved, wiped with an alcohol swab and left to dry, to ensure good connectivity. Pre- and post- measures of muscle activity and functional strength of the lower limbs were recorded in the Department of Human Kinetics and Ergonomics. The protocol took place at the Kingswood High Performance Centre, which is in close proximity to the initial testing site. The protocol involved players bowling eight overs (48 balls). During the protocol, accuracy, ball release speed and perceptual measures were recorded at the end of each over. After the protocol, players were driven back to the Human Kinetics and Ergonomics Department where post-testing measures were completed. The dependable variables of interest were muscle activation, functional strength of the lower limbs, ‘local’ ratings of perceived exertion (RPE), body discomfort, accuracy, and ball release speed. Results: For all muscles it was shown that, as the speed increased so did the muscle activity in players’ lower limbs. There were no significant changes in muscle activity preversus post-protocol. There was however, a general trend of decreasing muscle activity post protocol at higher testing speeds. There were significant (p<0.05) decreases in peak power following the simulated eight over bowling spell. ‘Local’ RPE displayed a significant (P<0.05) increase with each additional over and were observed to reach the ‘heavy’ category. The players’ highest discomfort area was in the lower back, with 13 players perceiving discomfort in this region following the eight over spell. The shoulder and chest were another two areas player’s indicated discomfort with eight players selecting the dominant shoulder. Seven players complained of the dominant side pectoral muscle, leading foot and dominant latissimus dorsi muscle being uncomfortable. Interestingly, the dominant pectoral showed the highest body discomfort ratings amongst players. There were no significant changes in accuracy between overs although there were large interindividual differences in accuracy points between players. The decrease in ball release speed observed during over seven was shown to be significantly (p<0.05) lower than overs one to four. Conclusion: The power output and perceived strain results of the players, appears to indicate the presence of fatigue in players. However, the results are not conclusive, as the fatigue was not shown in muscle recruitment patterns, as well as the body discomfort ratings. There was a non-significant trend observed in the lower limb muscle activation decreasing at higher speeds. Players were able to maintain accuracy. However, the significantly lower ball release speed observed during over seven showed players performance decreasing.
- Full Text:
- Authors: Barford, Gareth Charles
- Date: 2013
- Subjects: Cricket -- Bowling , Sports -- Physiological aspects , Muscles -- Wounds and injuries , Fatigue , Physical fitness , Cricket injuries
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5102 , http://hdl.handle.net/10962/d1003926 , Cricket -- Bowling , Sports -- Physiological aspects , Muscles -- Wounds and injuries , Fatigue , Physical fitness , Cricket injuries
- Description: Background: The musculoskeletal demands placed on the lower limb musculature of fast bowlers over time have not received much attention. In particular, measures of muscle recruitment changes have, to the author’s knowledge, not been considered. Objective: The present study, therefore sought to establish any associations between an eight over, simulated fast bowling spell, and muscle activation patterns, power output, perceptual demands, and changes in performance. This will enable improvements in the development of training programmes. Methods: Players’ were required to attend two sessions in total. The purpose of the initial session was to collect specific demographic, anthropometric and physiological data and injury history information from each player. In addition, this first session allowed for habituation with the treadmill, the jump meter and all other equipment involved in experimentation. The second testing session involved electrode attachment sites being identified on player’s dominant leg. The areas were then shaved, wiped with an alcohol swab and left to dry, to ensure good connectivity. Pre- and post- measures of muscle activity and functional strength of the lower limbs were recorded in the Department of Human Kinetics and Ergonomics. The protocol took place at the Kingswood High Performance Centre, which is in close proximity to the initial testing site. The protocol involved players bowling eight overs (48 balls). During the protocol, accuracy, ball release speed and perceptual measures were recorded at the end of each over. After the protocol, players were driven back to the Human Kinetics and Ergonomics Department where post-testing measures were completed. The dependable variables of interest were muscle activation, functional strength of the lower limbs, ‘local’ ratings of perceived exertion (RPE), body discomfort, accuracy, and ball release speed. Results: For all muscles it was shown that, as the speed increased so did the muscle activity in players’ lower limbs. There were no significant changes in muscle activity preversus post-protocol. There was however, a general trend of decreasing muscle activity post protocol at higher testing speeds. There were significant (p<0.05) decreases in peak power following the simulated eight over bowling spell. ‘Local’ RPE displayed a significant (P<0.05) increase with each additional over and were observed to reach the ‘heavy’ category. The players’ highest discomfort area was in the lower back, with 13 players perceiving discomfort in this region following the eight over spell. The shoulder and chest were another two areas player’s indicated discomfort with eight players selecting the dominant shoulder. Seven players complained of the dominant side pectoral muscle, leading foot and dominant latissimus dorsi muscle being uncomfortable. Interestingly, the dominant pectoral showed the highest body discomfort ratings amongst players. There were no significant changes in accuracy between overs although there were large interindividual differences in accuracy points between players. The decrease in ball release speed observed during over seven was shown to be significantly (p<0.05) lower than overs one to four. Conclusion: The power output and perceived strain results of the players, appears to indicate the presence of fatigue in players. However, the results are not conclusive, as the fatigue was not shown in muscle recruitment patterns, as well as the body discomfort ratings. There was a non-significant trend observed in the lower limb muscle activation decreasing at higher speeds. Players were able to maintain accuracy. However, the significantly lower ball release speed observed during over seven showed players performance decreasing.
- Full Text:
Characterisation of a plasmodium falciparum type II Hsp40 chaperone exported to the cytosol of infected erythrocytes
- Maphumulo, Philile Nompumelelo
- Authors: Maphumulo, Philile Nompumelelo
- Date: 2013
- Subjects: Erythrocytes , Heat shock proteins , Plasmodium falciparum , Molecular chaperones , Malaria -- Prevention -- Research , Protein folding , Proteins -- Analysis , Malaria -- Immunological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4128 , http://hdl.handle.net/10962/d1015681
- Description: Heat Shock 40 kDa proteins (Hsp40s) partner with heat shock 70 kDa proteins (Hsp70s) in facilitating, among other chaperone activities; correct protein transport, productive protein folding and assembly within the cells; under both normal and stressful conditions. Hsp40 proteins regulate the ATPase activity of Hsp70 through interaction with the J-domain. Plasmodium falciparum Hsp70s (PfHsp70s) do not contain a Plasmodium export element (PEXEL) sequence although PfHsp70-1 and PfHsp70-3 have been located outside of the parasitophorous vacuole. Studies reveal that a type I P. falciparum (PfHsp40) chaperone (PF14_0359) stimulates the rate of ATP hydrolysis of the cytosolic PfHsp70 (PfHsp70-1) and that of human Hsp70A1A. PFE0055c is a PEXEL-bearing type II Hsp40 that is exported into the cytosol of P. falciparum-infected erythrocytes; where it potentially interacts with human Hsp70. Studies reveal that PFE0055c associates with structures found in the erythrocyte cytosol termed “J-dots” which are believed to be involved in trafficking parasite-encoded proteins through the erythrocyte cytosol. If P. falciparum exports PFE0055c into the host cytosol, it may be proposed that it interacts with human Hsp70, making it a possible drug target. The effect of PFE0055c on the ATPase activity of human Hsp70A1A has not been previously characterised. Central to this study was bioinformatic analysis and biochemical characterisation PFE0055c using an in vitro (ATPase assay) approach. Structural domains that classify PFE0055c as a type II Hsp40 were identified with similarity to two other exported type II PfHsp40s. Plasmids encoding the hexahistidine-tagged versions of PFE0055c and human Hsp70A1A were used for the expression and purification of these proteins from Escherichia coli. Purification was achieved using nickel affinity chromatography. The urea-denaturing method was used to obtain the purified PFE0055c whilst human Hsp70A1A was purified using the native method. PFE0055c could stimulate the ATPase activity of alfalfa Hsp70, although such was not the case for human Hsp70A1A in vitro.
- Full Text:
- Authors: Maphumulo, Philile Nompumelelo
- Date: 2013
- Subjects: Erythrocytes , Heat shock proteins , Plasmodium falciparum , Molecular chaperones , Malaria -- Prevention -- Research , Protein folding , Proteins -- Analysis , Malaria -- Immunological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4128 , http://hdl.handle.net/10962/d1015681
- Description: Heat Shock 40 kDa proteins (Hsp40s) partner with heat shock 70 kDa proteins (Hsp70s) in facilitating, among other chaperone activities; correct protein transport, productive protein folding and assembly within the cells; under both normal and stressful conditions. Hsp40 proteins regulate the ATPase activity of Hsp70 through interaction with the J-domain. Plasmodium falciparum Hsp70s (PfHsp70s) do not contain a Plasmodium export element (PEXEL) sequence although PfHsp70-1 and PfHsp70-3 have been located outside of the parasitophorous vacuole. Studies reveal that a type I P. falciparum (PfHsp40) chaperone (PF14_0359) stimulates the rate of ATP hydrolysis of the cytosolic PfHsp70 (PfHsp70-1) and that of human Hsp70A1A. PFE0055c is a PEXEL-bearing type II Hsp40 that is exported into the cytosol of P. falciparum-infected erythrocytes; where it potentially interacts with human Hsp70. Studies reveal that PFE0055c associates with structures found in the erythrocyte cytosol termed “J-dots” which are believed to be involved in trafficking parasite-encoded proteins through the erythrocyte cytosol. If P. falciparum exports PFE0055c into the host cytosol, it may be proposed that it interacts with human Hsp70, making it a possible drug target. The effect of PFE0055c on the ATPase activity of human Hsp70A1A has not been previously characterised. Central to this study was bioinformatic analysis and biochemical characterisation PFE0055c using an in vitro (ATPase assay) approach. Structural domains that classify PFE0055c as a type II Hsp40 were identified with similarity to two other exported type II PfHsp40s. Plasmids encoding the hexahistidine-tagged versions of PFE0055c and human Hsp70A1A were used for the expression and purification of these proteins from Escherichia coli. Purification was achieved using nickel affinity chromatography. The urea-denaturing method was used to obtain the purified PFE0055c whilst human Hsp70A1A was purified using the native method. PFE0055c could stimulate the ATPase activity of alfalfa Hsp70, although such was not the case for human Hsp70A1A in vitro.
- Full Text:
Characterisation of surfaces modified through self-assembled monolayers and click chemistry
- Authors: Coates, Megan Patricia
- Date: 2013
- Subjects: Monomolecular films Gold Adsorption Nanotubes Self-assembly (Chemistry) Self-assembly (Chemistry) Scanning electrochemical microscopy X-ray photoelectron spectroscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4277 , http://hdl.handle.net/10962/d1001684
- Description: Different approaches to surface modification were investigated in this work on gold, glassy carbon, multi-walled carbon nanotube paper and on single-walled carbon nanotubes adsorbed on glassy carbon. These approaches include electrochemical grafting, electropolymerisation, click chemistry, axial ligation, adsorption and self-assembled monolayers. The modified surfaces were characterised using a variety of techniques; predominantly electrochemistry, scanning electrochemical microscopy and X-ray photoelectron spectroscopy. For the formation of self-assembled monolayers on gold, four new manganese(III) phthalocyanines (1a-d), octa-substituted at the peripheral position with pentylthio, decylthio, benzylthio, and phenylthio groups were synthesized and characterised. X-ray photoelectron spectroscopy was used to show the formation of a sulphur-gold bond. A number of approaches using 4-azidoaniline (2a) combined with azide-alkyne click chemistry and electrochemistry were also used to anchor ferrocene and pyridine moieties on to the carbon surfaces, including direct in situ diazotation and grafting, electropolymerisation, and the synthesis of the diazonium salt followed by grafting. Iron phthalocyanine was linked to the pyridine-clicked surfaces through axial ligation, where the strong axial bond formed by the interaction between the central metal and the lone pair of the nitrogen in the pyridine group resulted in stable modified electrodes. The potential of these surfaces for the detection of analytes such as thiocyanate, hydrazine and sulphite are briefly shown as well. This work also describes for the first time the possibility of performing local micro-electrochemical grafting of a gold substrate by 4-azidobenzenediazonium (2b) using scanning electrochemical microscopy in a single and simple one step approach, without complications from adsorption.
- Full Text:
- Authors: Coates, Megan Patricia
- Date: 2013
- Subjects: Monomolecular films Gold Adsorption Nanotubes Self-assembly (Chemistry) Self-assembly (Chemistry) Scanning electrochemical microscopy X-ray photoelectron spectroscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4277 , http://hdl.handle.net/10962/d1001684
- Description: Different approaches to surface modification were investigated in this work on gold, glassy carbon, multi-walled carbon nanotube paper and on single-walled carbon nanotubes adsorbed on glassy carbon. These approaches include electrochemical grafting, electropolymerisation, click chemistry, axial ligation, adsorption and self-assembled monolayers. The modified surfaces were characterised using a variety of techniques; predominantly electrochemistry, scanning electrochemical microscopy and X-ray photoelectron spectroscopy. For the formation of self-assembled monolayers on gold, four new manganese(III) phthalocyanines (1a-d), octa-substituted at the peripheral position with pentylthio, decylthio, benzylthio, and phenylthio groups were synthesized and characterised. X-ray photoelectron spectroscopy was used to show the formation of a sulphur-gold bond. A number of approaches using 4-azidoaniline (2a) combined with azide-alkyne click chemistry and electrochemistry were also used to anchor ferrocene and pyridine moieties on to the carbon surfaces, including direct in situ diazotation and grafting, electropolymerisation, and the synthesis of the diazonium salt followed by grafting. Iron phthalocyanine was linked to the pyridine-clicked surfaces through axial ligation, where the strong axial bond formed by the interaction between the central metal and the lone pair of the nitrogen in the pyridine group resulted in stable modified electrodes. The potential of these surfaces for the detection of analytes such as thiocyanate, hydrazine and sulphite are briefly shown as well. This work also describes for the first time the possibility of performing local micro-electrochemical grafting of a gold substrate by 4-azidobenzenediazonium (2b) using scanning electrochemical microscopy in a single and simple one step approach, without complications from adsorption.
- Full Text:
Characterization and application of phthalocyanine-gold nanoparticle conjugates
- Authors: Tombe, Sekai Lana
- Date: 2013
- Subjects: Phthalocyanines , Gold , Zinc , Nanoparticles , Bioconjugates , Photochemistry , Photocatalysis , Electrospinning , Polymers , Pollutants , Phenols , Azo dyes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4293 , http://hdl.handle.net/10962/d1004517 , Phthalocyanines , Gold , Zinc , Nanoparticles , Bioconjugates , Photochemistry , Photocatalysis , Electrospinning , Polymers , Pollutants , Phenols , Azo dyes
- Description: This work presents the syntheses, photophysical and photochemical characterization of arylthio zinc phthalocyanines and their gold nanoparticle conjugates. Spectroscopic and microscopic studies confirmed the formation of the phthalocyanine-gold nanoparticle conjugates which exhibited enhanced photophysicochemical properties in comparison to the phthalocyanines. The studies showed that the presence of gold nanoparticles significantly lowered fluorescence quantum yields and lifetimes. However, this interaction did not restrict the formation of excited singlet and triplet states and hence the formation of singlet oxygen required for photocatalysis. The conjugates showed significantly higher singlet oxygen quantum yields and therefore enhanced photocatalytic activity compared to the phthalocyanines. The zinc phthalocyanines and their gold nanoparticle conjugates were successfully incorporated into electrospun polymer fibers. Spectral characteristics of the functionalized electrospun fibers indicated that the phthalocyanines and phthalocyanine-gold nanoparticle conjugates were bound and their integrity was maintained within the polymeric fiber matrices. The photophysical and photochemical properties of the complexes were equally maintained within the electrospun fibers. The functionalized fibers were applied for the photoconversion of 4-chlorophenol and Orange G as model organic pollutants. , Microsoft� Word 2010 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Authors: Tombe, Sekai Lana
- Date: 2013
- Subjects: Phthalocyanines , Gold , Zinc , Nanoparticles , Bioconjugates , Photochemistry , Photocatalysis , Electrospinning , Polymers , Pollutants , Phenols , Azo dyes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4293 , http://hdl.handle.net/10962/d1004517 , Phthalocyanines , Gold , Zinc , Nanoparticles , Bioconjugates , Photochemistry , Photocatalysis , Electrospinning , Polymers , Pollutants , Phenols , Azo dyes
- Description: This work presents the syntheses, photophysical and photochemical characterization of arylthio zinc phthalocyanines and their gold nanoparticle conjugates. Spectroscopic and microscopic studies confirmed the formation of the phthalocyanine-gold nanoparticle conjugates which exhibited enhanced photophysicochemical properties in comparison to the phthalocyanines. The studies showed that the presence of gold nanoparticles significantly lowered fluorescence quantum yields and lifetimes. However, this interaction did not restrict the formation of excited singlet and triplet states and hence the formation of singlet oxygen required for photocatalysis. The conjugates showed significantly higher singlet oxygen quantum yields and therefore enhanced photocatalytic activity compared to the phthalocyanines. The zinc phthalocyanines and their gold nanoparticle conjugates were successfully incorporated into electrospun polymer fibers. Spectral characteristics of the functionalized electrospun fibers indicated that the phthalocyanines and phthalocyanine-gold nanoparticle conjugates were bound and their integrity was maintained within the polymeric fiber matrices. The photophysical and photochemical properties of the complexes were equally maintained within the electrospun fibers. The functionalized fibers were applied for the photoconversion of 4-chlorophenol and Orange G as model organic pollutants. , Microsoft� Word 2010 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
China's African FDI safari : opportunistic exploitation or muturally beneficial to all participants
- Dreier, Tina, Rhodes University
- Authors: Dreier, Tina , Rhodes University
- Date: 2013 , 2013-04-10
- Subjects: Africa -- Foreign economic relations -- China , China -- Foreign economic relations -- Africa , Investments, Foreign -- China , Foreign direct investment
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:929 , http://hdl.handle.net/10962/d1001455 , Africa -- Foreign economic relations -- China , China -- Foreign economic relations -- Africa , Investments, Foreign -- China
- Description: When implemented within a favourable legislative framework, Foreign Direct Investment (FDI) can produce domestic growth-enhancing spillovers in host countries. Other potential positive effects include the provision of investment capital, the creation of local employment and the transfer of sophisticated technology or advanced knowledge. African nations in particular have been historically reliant on externally-provided funds. Prevailing low income levels, marginal savings rates and the absence of functioning financial markets necessary to provide local start-up capital continue to keep Africa reliant on foreign inflows. Considering China’s increasing financial commitments to Sub- Saharan Africa (SSA) over the last decade, this study examines the state of current Sino-African investment relationships. Specific attention is paid to the outcomes of this strategic bilateral alliance in order to determine whether or not a mutually beneficial investment relationship has evolved. The distinct nature and structure of, the motivation behind and the most significant determinants of Chinese FDI to SSA are all analysed in accordance with traditional FDI theories. A case study approach is used to establish whether China’s contemporary interest in SSA differs from historical investments and to also investigate country-specific commonalities and differences. Of particular relevance to SSA are resource-backed Chinese loans that finance major infrastructure projects in host nations. Interestingly, a lot of the Sino-African investment packages resemble similar deals struck between China and Japan in the 1970s. The results of this study indicate that China’s investment motives seem more diverse than initially expected. Resource-seeking, profit-seeking and market access-seeking reasons appear to be the most important motives. After establishing the Top- Ten recipients of Chinese FDI in SSA, these nations are then classified into three major categories: resource-, oil- or agricultural-rich nations. Undiversified resource- or oil-rich economies are found to have secured the largest shares of Chinese FDI. This study suggests that China’s contemporary “African Safari” is an unconventional way of providing financial assistance. Rather than solely supplying FDI, China finances a diverse mix of instruments, the most important being concessional loans, export credits, zero-interest loans and the establishment of Special Economic Zones. A profound difference to traditional Western investment packages is China’s non-interference approach. Accordingly, Beijing not only refrains from intervening in host countries’ domestic affairs but also refuses to attach formal conditionalties to its loans. China’s “financial safari” into Africa has produced many positive as well as negative effects in host countries. Nevertheless, it would seem that the positive effects outweigh the negative and China’s FDI could contribute to sustainable development in SSA
- Full Text:
- Authors: Dreier, Tina , Rhodes University
- Date: 2013 , 2013-04-10
- Subjects: Africa -- Foreign economic relations -- China , China -- Foreign economic relations -- Africa , Investments, Foreign -- China , Foreign direct investment
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:929 , http://hdl.handle.net/10962/d1001455 , Africa -- Foreign economic relations -- China , China -- Foreign economic relations -- Africa , Investments, Foreign -- China
- Description: When implemented within a favourable legislative framework, Foreign Direct Investment (FDI) can produce domestic growth-enhancing spillovers in host countries. Other potential positive effects include the provision of investment capital, the creation of local employment and the transfer of sophisticated technology or advanced knowledge. African nations in particular have been historically reliant on externally-provided funds. Prevailing low income levels, marginal savings rates and the absence of functioning financial markets necessary to provide local start-up capital continue to keep Africa reliant on foreign inflows. Considering China’s increasing financial commitments to Sub- Saharan Africa (SSA) over the last decade, this study examines the state of current Sino-African investment relationships. Specific attention is paid to the outcomes of this strategic bilateral alliance in order to determine whether or not a mutually beneficial investment relationship has evolved. The distinct nature and structure of, the motivation behind and the most significant determinants of Chinese FDI to SSA are all analysed in accordance with traditional FDI theories. A case study approach is used to establish whether China’s contemporary interest in SSA differs from historical investments and to also investigate country-specific commonalities and differences. Of particular relevance to SSA are resource-backed Chinese loans that finance major infrastructure projects in host nations. Interestingly, a lot of the Sino-African investment packages resemble similar deals struck between China and Japan in the 1970s. The results of this study indicate that China’s investment motives seem more diverse than initially expected. Resource-seeking, profit-seeking and market access-seeking reasons appear to be the most important motives. After establishing the Top- Ten recipients of Chinese FDI in SSA, these nations are then classified into three major categories: resource-, oil- or agricultural-rich nations. Undiversified resource- or oil-rich economies are found to have secured the largest shares of Chinese FDI. This study suggests that China’s contemporary “African Safari” is an unconventional way of providing financial assistance. Rather than solely supplying FDI, China finances a diverse mix of instruments, the most important being concessional loans, export credits, zero-interest loans and the establishment of Special Economic Zones. A profound difference to traditional Western investment packages is China’s non-interference approach. Accordingly, Beijing not only refrains from intervening in host countries’ domestic affairs but also refuses to attach formal conditionalties to its loans. China’s “financial safari” into Africa has produced many positive as well as negative effects in host countries. Nevertheless, it would seem that the positive effects outweigh the negative and China’s FDI could contribute to sustainable development in SSA
- Full Text:
Climate variability and climate change in water resources management of the Zambezi River basin
- Authors: Tirivarombo, Sithabile
- Date: 2013
- Subjects: Water resources development -- Zambezi River Watershed Climatic changes -- Zambezi River Watershed Water-supply -- Zambezi River Watershed Water-supply -- Political aspects -- Africa, Southern Water rights -- Africa, Southern Water security -- Africa, Southern Rain and rainfall -- Africa, Southern Rainfall probabilities -- Africa, Southern Food security -- Africa, Southern Drought forecasting -- Africa, Southern Watersheds -- Africa, Southern Water supply -- Measurement -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6024 , http://hdl.handle.net/10962/d1002955
- Description: Water is recognised as a key driver for social and economic development in the Zambezi basin. The basin is riparian to eight southern African countries and the transboundary nature of the basin’s water resources can be viewed as an agent of cooperation between the basin countries. It is possible, however, that the same water resource can lead to conflicts between water users. The southern African Water Vision for ‘equitable and sustainable utilisation of water for social, environmental justice and economic benefits for the present and future generations’ calls for an integrated and efficient management of water resources within the basin. Ensuring water and food security in the Zambezi basin is, however, faced with challenges due to high variability in climate and the available water resources. Water resources are under continuous threat from pollution, increased population growth, development and urbanisation as well as global climate change. These factors increase the demand for freshwater resources and have resulted in water being one of the major driving forces for development. The basin is also vulnerable due to lack of adequate financial resources and appropriate water resources infrastructure to enable viable, equitable and sustainable distribution of the water resources. This is in addition to the fact that the basin’s economic mainstay and social well-being are largely dependent on rainfed agriculture. There is also competition among the different water users and this has the potential to generate conflicts, which further hinder the development of water resources in the basin. This thesis has focused on the Zambezi River basin emphasising climate variability and climate change. It is now considered common knowledge that the global climate is changing and that many of the impacts will be felt through water resources. If these predictions are correct then the Zambezi basin is most likely to suffer under such impacts since its economic mainstay is largely determined by the availability of rainfall. It is the belief of this study that in order to ascertain the impacts of climate change, there should be a basis against which this change is evaluated. If we do not know the historical patterns of variability it may be difficult to predict changes in the future climate and in the hydrological resources and it will certainly be difficult to develop appropriate management strategies. Reliable quantitative estimates of water availability are a prerequisite for successful water resource plans. However, such initiatives have been hindered by paucity in data especially in a basin where gauging networks are inadequate and some of them have deteriorated. This is further compounded by shortages in resources, both human and financial, to ensure adequate monitoring. To address the data problems, this study largely relied on global data sets and the CRU TS2.1 rainfall grids were used for a large part of this study. The study starts by assessing the historical variability of rainfall and streamflow in the Zambezi basin and the results are used to inform the prediction of change in the future. Various methods of assessing historical trends were employed and regional drought indices were generated and evaluated against the historical rainfall trends. The study clearly demonstrates that the basin has a high degree of temporal and spatial variability in rainfall and streamflow at inter-annual and multi-decadal scales. The Standardised Precipitation Index, a rainfall based drought index, is used to assess historical drought events in the basin and it is shown that most of the droughts that have occurred were influenced by climatic and hydrological variability. It is concluded, through the evaluation of agricultural maize yields, that the basin’s food security is mostly constrained by the availability of rainfall. Comparing the viability of using a rainfall based index to a soil moisture based index as an agricultural drought indicator, this study concluded that a soil moisture based index is a better indicator since all of the water balance components are considered in the generation of the index. This index presents the actual amount of water available for the plant unlike purely rainfall based indices, that do not account for other components of the water budget that cause water losses. A number of challenges were, however, faced in assessing the variability and historical drought conditions, mainly due to the fact that most parts of the Zambezi basin are ungauged and available data are sparse, short and not continuous (with missing gaps). Hydrological modelling is frequently used to bridge the data gap and to facilitate the quantification of a basin’s hydrology for both gauged and ungauged catchments. The trend has been to use various methods of regionalisation to transfer information from gauged basins, or from basins with adequate physical basin data, to ungauged basins. All this is done to ensure that water resources are accounted for and that the future can be well planned. A number of approaches leading to the evaluation of the basin’s hydrological response to future climate change scenarios are taken. The Pitman rainfall-runoff model has enjoyed wide use as a water resources estimation tool in southern Africa. The model has been calibrated for the Zambezi basin but it should be acknowledged that any hydrological modelling process is characterised by many uncertainties arising from limitations in input data and inherent model structural uncertainty. The calibration process is thus carried out in a manner that embraces some of the uncertainties. Initial ranges of parameter values (maximum and minimum) that incorporate the possible parameter uncertainties are assigned in relation to physical basin properties. These parameter sets are used as input to the uncertainty version of the model to generate behavioural parameter space which is then further modified through manual calibration. The use of parameter ranges initially guided by the basin physical properties generates streamflows that adequately represent the historically observed amounts. This study concludes that the uncertainty framework and the Pitman model perform quite well in the Zambezi basin. Based on assumptions of an intensifying hydrological cycle, climate changes are frequently expected to result in negative impacts on water resources. However, it is important that basin scale assessments are undertaken so that appropriate future management strategies can be developed. To assess the likely changes in the Zambezi basin, the calibrated Pitman model was forced with downscaled and bias corrected GCM data. Three GCMs were used for this study, namely; ECHAM, GFDL and IPSL. The general observation made in this study is that the near future (2046-2065) conditions of the Zambezi basin are expected to remain within the ranges of historically observed variability. The differences between the predictions for the three GCMs are an indication of the uncertainties in the future and it has not been possible to make any firm conclusions about directions of change. It is therefore recommended that future water resources management strategies account for historical patterns of variability, but also for increased uncertainty. Any management strategies that are able to satisfactorily deal with the large variability that is evident from the historical data should be robust enough to account for the near future patterns of water availability predicted by this study. However, the uncertainties in these predictions suggest that improved monitoring systems are required to provide additional data against which future model outputs can be assessed.
- Full Text:
- Authors: Tirivarombo, Sithabile
- Date: 2013
- Subjects: Water resources development -- Zambezi River Watershed Climatic changes -- Zambezi River Watershed Water-supply -- Zambezi River Watershed Water-supply -- Political aspects -- Africa, Southern Water rights -- Africa, Southern Water security -- Africa, Southern Rain and rainfall -- Africa, Southern Rainfall probabilities -- Africa, Southern Food security -- Africa, Southern Drought forecasting -- Africa, Southern Watersheds -- Africa, Southern Water supply -- Measurement -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6024 , http://hdl.handle.net/10962/d1002955
- Description: Water is recognised as a key driver for social and economic development in the Zambezi basin. The basin is riparian to eight southern African countries and the transboundary nature of the basin’s water resources can be viewed as an agent of cooperation between the basin countries. It is possible, however, that the same water resource can lead to conflicts between water users. The southern African Water Vision for ‘equitable and sustainable utilisation of water for social, environmental justice and economic benefits for the present and future generations’ calls for an integrated and efficient management of water resources within the basin. Ensuring water and food security in the Zambezi basin is, however, faced with challenges due to high variability in climate and the available water resources. Water resources are under continuous threat from pollution, increased population growth, development and urbanisation as well as global climate change. These factors increase the demand for freshwater resources and have resulted in water being one of the major driving forces for development. The basin is also vulnerable due to lack of adequate financial resources and appropriate water resources infrastructure to enable viable, equitable and sustainable distribution of the water resources. This is in addition to the fact that the basin’s economic mainstay and social well-being are largely dependent on rainfed agriculture. There is also competition among the different water users and this has the potential to generate conflicts, which further hinder the development of water resources in the basin. This thesis has focused on the Zambezi River basin emphasising climate variability and climate change. It is now considered common knowledge that the global climate is changing and that many of the impacts will be felt through water resources. If these predictions are correct then the Zambezi basin is most likely to suffer under such impacts since its economic mainstay is largely determined by the availability of rainfall. It is the belief of this study that in order to ascertain the impacts of climate change, there should be a basis against which this change is evaluated. If we do not know the historical patterns of variability it may be difficult to predict changes in the future climate and in the hydrological resources and it will certainly be difficult to develop appropriate management strategies. Reliable quantitative estimates of water availability are a prerequisite for successful water resource plans. However, such initiatives have been hindered by paucity in data especially in a basin where gauging networks are inadequate and some of them have deteriorated. This is further compounded by shortages in resources, both human and financial, to ensure adequate monitoring. To address the data problems, this study largely relied on global data sets and the CRU TS2.1 rainfall grids were used for a large part of this study. The study starts by assessing the historical variability of rainfall and streamflow in the Zambezi basin and the results are used to inform the prediction of change in the future. Various methods of assessing historical trends were employed and regional drought indices were generated and evaluated against the historical rainfall trends. The study clearly demonstrates that the basin has a high degree of temporal and spatial variability in rainfall and streamflow at inter-annual and multi-decadal scales. The Standardised Precipitation Index, a rainfall based drought index, is used to assess historical drought events in the basin and it is shown that most of the droughts that have occurred were influenced by climatic and hydrological variability. It is concluded, through the evaluation of agricultural maize yields, that the basin’s food security is mostly constrained by the availability of rainfall. Comparing the viability of using a rainfall based index to a soil moisture based index as an agricultural drought indicator, this study concluded that a soil moisture based index is a better indicator since all of the water balance components are considered in the generation of the index. This index presents the actual amount of water available for the plant unlike purely rainfall based indices, that do not account for other components of the water budget that cause water losses. A number of challenges were, however, faced in assessing the variability and historical drought conditions, mainly due to the fact that most parts of the Zambezi basin are ungauged and available data are sparse, short and not continuous (with missing gaps). Hydrological modelling is frequently used to bridge the data gap and to facilitate the quantification of a basin’s hydrology for both gauged and ungauged catchments. The trend has been to use various methods of regionalisation to transfer information from gauged basins, or from basins with adequate physical basin data, to ungauged basins. All this is done to ensure that water resources are accounted for and that the future can be well planned. A number of approaches leading to the evaluation of the basin’s hydrological response to future climate change scenarios are taken. The Pitman rainfall-runoff model has enjoyed wide use as a water resources estimation tool in southern Africa. The model has been calibrated for the Zambezi basin but it should be acknowledged that any hydrological modelling process is characterised by many uncertainties arising from limitations in input data and inherent model structural uncertainty. The calibration process is thus carried out in a manner that embraces some of the uncertainties. Initial ranges of parameter values (maximum and minimum) that incorporate the possible parameter uncertainties are assigned in relation to physical basin properties. These parameter sets are used as input to the uncertainty version of the model to generate behavioural parameter space which is then further modified through manual calibration. The use of parameter ranges initially guided by the basin physical properties generates streamflows that adequately represent the historically observed amounts. This study concludes that the uncertainty framework and the Pitman model perform quite well in the Zambezi basin. Based on assumptions of an intensifying hydrological cycle, climate changes are frequently expected to result in negative impacts on water resources. However, it is important that basin scale assessments are undertaken so that appropriate future management strategies can be developed. To assess the likely changes in the Zambezi basin, the calibrated Pitman model was forced with downscaled and bias corrected GCM data. Three GCMs were used for this study, namely; ECHAM, GFDL and IPSL. The general observation made in this study is that the near future (2046-2065) conditions of the Zambezi basin are expected to remain within the ranges of historically observed variability. The differences between the predictions for the three GCMs are an indication of the uncertainties in the future and it has not been possible to make any firm conclusions about directions of change. It is therefore recommended that future water resources management strategies account for historical patterns of variability, but also for increased uncertainty. Any management strategies that are able to satisfactorily deal with the large variability that is evident from the historical data should be robust enough to account for the near future patterns of water availability predicted by this study. However, the uncertainties in these predictions suggest that improved monitoring systems are required to provide additional data against which future model outputs can be assessed.
- Full Text:
Coming clean: the treatment of traces
- Authors: Wilmot, Cassandra
- Date: 2013 , 2013-09-13
- Subjects: Salcedo, Doris, 1958- Bereavement in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2442 , http://hdl.handle.net/10962/d1006121
- Description: Coming Clean is a mixed media installation which aims to address and express ambivalent feelings or notions of loss arising particularly in the absence of a comprehensive narrative or history by focussing on what remains. By researching the role of indexical signs and strategies, particularly as they are deployed by the artist Doris Salcedo, I explore the capacity for these traces to not only effectively mark and memorialise loss, but to also convey the state of loss as experienced by the bereaved without providing a narrative account of the events which preceded them. The domestic ritual of washing is both alluded to and used as a metaphor in etchings, photographic prints and readymade objects to illustrate my concerns, with particular emphasis on the dialectic between what is revealed or concealed. Using representations or traces of this task of laundry to examine this dialectic between concealment and revelation, I comment on the anxiety of dealing with incomplete narrative inheritances by considering how traces of the past which impose themselves on the present may affect both remembrance and the ritual of loss, while also taking into account the complexities behind the disclosure of sensitive information in families.
- Full Text:
- Authors: Wilmot, Cassandra
- Date: 2013 , 2013-09-13
- Subjects: Salcedo, Doris, 1958- Bereavement in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2442 , http://hdl.handle.net/10962/d1006121
- Description: Coming Clean is a mixed media installation which aims to address and express ambivalent feelings or notions of loss arising particularly in the absence of a comprehensive narrative or history by focussing on what remains. By researching the role of indexical signs and strategies, particularly as they are deployed by the artist Doris Salcedo, I explore the capacity for these traces to not only effectively mark and memorialise loss, but to also convey the state of loss as experienced by the bereaved without providing a narrative account of the events which preceded them. The domestic ritual of washing is both alluded to and used as a metaphor in etchings, photographic prints and readymade objects to illustrate my concerns, with particular emphasis on the dialectic between what is revealed or concealed. Using representations or traces of this task of laundry to examine this dialectic between concealment and revelation, I comment on the anxiety of dealing with incomplete narrative inheritances by considering how traces of the past which impose themselves on the present may affect both remembrance and the ritual of loss, while also taking into account the complexities behind the disclosure of sensitive information in families.
- Full Text:
Constructions of nationhood in secession debates related to Mthwakazi Liberation Front in Bulawayo's Chronicle and Newsday newspapers in 2011
- Authors: Ndlovu, Mphathisi
- Date: 2013
- Subjects: Newspapers , Bulawayo , Matabeleland , Zimbabwe , Chronicle , Newsday , Secession , Devolution , Nationhood , Ndebele , Ethnic identity , Mthwakazi Liberation Front , Mthwakazi Liberation Front -- Zimbabwe , Mass media and nationalism -- Research -- Zimbabwe , Bulawayo (Zimbabwe) -- Newspapers , Matabeleland (Zimbabwe) -- History -- Autonomy and independence movements , Matabeleland (Zimbabwe) -- Social conditions , Zimbabwe -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3415 , http://hdl.handle.net/10962/d1001846
- Description: This study investigates the constructions of nationhood in two Bulawayo newspapers, the Chronicle and Newsday. Against the backdrop of the emergence of a secessionist movement, Mthwakazi Liberation Front (MLF), this research examines the discourses of nationhood in the secessionist debates raging in these two newspapers. This study is premised on a view that nationhood constructions cannot be understood outside the broader context in which these newspapers are embedded. Accordingly, it traces the roots and resurgence of Matabeleland separatist politics, exploring the political-historical forces that have shaped a distinctive Ndebele identity that poses a threat to the one, indivisible Zimbabwean national identity. Further, the study situates Matabeleland separatist politics within the broader African secessionist discourse challenging the post-colonial nation-building project on the continent. Informed by Hall’s (1992, 1996) constructivist approach to identity, it considers national identities as fragmented, multiple and constantly evolving. Thus, this study is framed within Hall’s (1997) constructivist approach to representation, as it examines the constructions of nationhood in and through language. The study uses qualitative research methods, as it examines the meanings of nationhood in key media texts. Informed by Foucault’s discourse theory, this research employs critical discourse analysis (CDA) to analyse 12 articles from the two newspapers. The findings confirm that the representations of nationhood in the two newspapers are influenced by their position within the socio-political context. The state-owned Chronicle legitimates the unitary state discourse advocated by ZANU PF. On the other hand, Newsday’s representations are informed by the discourses of the opposition political parties and civil society that challenge the dominant nation-building project. Thus, within this paper, secession and devolution emerge as alternative imaginaries that contest the authoritarian discourse of nationhood
- Full Text:
- Authors: Ndlovu, Mphathisi
- Date: 2013
- Subjects: Newspapers , Bulawayo , Matabeleland , Zimbabwe , Chronicle , Newsday , Secession , Devolution , Nationhood , Ndebele , Ethnic identity , Mthwakazi Liberation Front , Mthwakazi Liberation Front -- Zimbabwe , Mass media and nationalism -- Research -- Zimbabwe , Bulawayo (Zimbabwe) -- Newspapers , Matabeleland (Zimbabwe) -- History -- Autonomy and independence movements , Matabeleland (Zimbabwe) -- Social conditions , Zimbabwe -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3415 , http://hdl.handle.net/10962/d1001846
- Description: This study investigates the constructions of nationhood in two Bulawayo newspapers, the Chronicle and Newsday. Against the backdrop of the emergence of a secessionist movement, Mthwakazi Liberation Front (MLF), this research examines the discourses of nationhood in the secessionist debates raging in these two newspapers. This study is premised on a view that nationhood constructions cannot be understood outside the broader context in which these newspapers are embedded. Accordingly, it traces the roots and resurgence of Matabeleland separatist politics, exploring the political-historical forces that have shaped a distinctive Ndebele identity that poses a threat to the one, indivisible Zimbabwean national identity. Further, the study situates Matabeleland separatist politics within the broader African secessionist discourse challenging the post-colonial nation-building project on the continent. Informed by Hall’s (1992, 1996) constructivist approach to identity, it considers national identities as fragmented, multiple and constantly evolving. Thus, this study is framed within Hall’s (1997) constructivist approach to representation, as it examines the constructions of nationhood in and through language. The study uses qualitative research methods, as it examines the meanings of nationhood in key media texts. Informed by Foucault’s discourse theory, this research employs critical discourse analysis (CDA) to analyse 12 articles from the two newspapers. The findings confirm that the representations of nationhood in the two newspapers are influenced by their position within the socio-political context. The state-owned Chronicle legitimates the unitary state discourse advocated by ZANU PF. On the other hand, Newsday’s representations are informed by the discourses of the opposition political parties and civil society that challenge the dominant nation-building project. Thus, within this paper, secession and devolution emerge as alternative imaginaries that contest the authoritarian discourse of nationhood
- Full Text:
Contributions of inshore and offshore sources of primary production to the foodweb, and the trophic connectivity between various habitats along a depth-gradient, in Sodwana Bay, Kwazulu-Natal, South Africa
- Authors: Parkinson, Matthew Cameron
- Date: 2013
- Subjects: Marine ecology -- South Africa -- Sodwana Bay , Food chains (Ecology) -- South Africa -- Sodwana Bay , Coastal ecology -- South Africa -- Sodwana Bay , Stable isotopes , Dinoflagellates , Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5179 , http://hdl.handle.net/10962/d1001630 , Marine ecology -- South Africa -- Sodwana Bay , Food chains (Ecology) -- South Africa -- Sodwana Bay , Coastal ecology -- South Africa -- Sodwana Bay , Stable isotopes , Dinoflagellates , Marine algae
- Description: Sodwana Bay, situated within the iSimangaliso Wetland Park, is ecologically important as it contains high-latitude corals and the most southerly known population of coelacanths. This thesis utilised stable isotope and lipid analyses to investigate the trophic ecology of the area, in particular, understanding the relative contribution of inshore and offshore primary production to consumers inhabiting intertidal and shallow subtidal, coral reef, deep reef, canyon head and pelagic habitats. Seaweeds, excluding certain species of red seaweeds with highly depleted carbon signatures, and phytoplankton, such as diatoms, were found to be the principal sources of primary production for all consumers. Offshore production was typified by dinoflagellates. Particulate organic matter (POM) was spatio-temporally variable. Three distinct productivity periods related to nutrient cycling were noted with enriched carbon signatures and higher organic matter loads associated with warmer water. Inshore primary production was an important source of carbon to consumers in all habitats with the exception of zooplankton that were more reliant on pelagic primary production. Benthic invertebrates reflected a gradient in the utilisation of inshore production, due to the reduced availability of this source further offshore. Consumers at the furthest sites offshore were found to include a substantial quantity of inshore-derived production in their diets. Fishes, which are more mobile, were found to incorporate a similar proportion of inshore production into their diets regardless of where they were collected from.
- Full Text:
- Authors: Parkinson, Matthew Cameron
- Date: 2013
- Subjects: Marine ecology -- South Africa -- Sodwana Bay , Food chains (Ecology) -- South Africa -- Sodwana Bay , Coastal ecology -- South Africa -- Sodwana Bay , Stable isotopes , Dinoflagellates , Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5179 , http://hdl.handle.net/10962/d1001630 , Marine ecology -- South Africa -- Sodwana Bay , Food chains (Ecology) -- South Africa -- Sodwana Bay , Coastal ecology -- South Africa -- Sodwana Bay , Stable isotopes , Dinoflagellates , Marine algae
- Description: Sodwana Bay, situated within the iSimangaliso Wetland Park, is ecologically important as it contains high-latitude corals and the most southerly known population of coelacanths. This thesis utilised stable isotope and lipid analyses to investigate the trophic ecology of the area, in particular, understanding the relative contribution of inshore and offshore primary production to consumers inhabiting intertidal and shallow subtidal, coral reef, deep reef, canyon head and pelagic habitats. Seaweeds, excluding certain species of red seaweeds with highly depleted carbon signatures, and phytoplankton, such as diatoms, were found to be the principal sources of primary production for all consumers. Offshore production was typified by dinoflagellates. Particulate organic matter (POM) was spatio-temporally variable. Three distinct productivity periods related to nutrient cycling were noted with enriched carbon signatures and higher organic matter loads associated with warmer water. Inshore primary production was an important source of carbon to consumers in all habitats with the exception of zooplankton that were more reliant on pelagic primary production. Benthic invertebrates reflected a gradient in the utilisation of inshore production, due to the reduced availability of this source further offshore. Consumers at the furthest sites offshore were found to include a substantial quantity of inshore-derived production in their diets. Fishes, which are more mobile, were found to incorporate a similar proportion of inshore production into their diets regardless of where they were collected from.
- Full Text:
Coping with HIV and AIDS in marginal communities: a case study of Chivanhu Settlement in Nemanwa, Masvingo, Zimbabwe
- Authors: Makonese, Loveness
- Date: 2013
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3337 , http://hdl.handle.net/10962/d1003744
- Description: This thesis seeks to understand and analyse HIV and AIDS and rural livelihoods in Zimbabwe with particular reference to an isolated and marginalised informal settlement called Chivanhu in Masvingo Province. The focus is specifically on questions around HIV susceptibility, AIDS vulnerability and household resilience. In this regard, it is important to recognise that HIV and AIDS cannot be lumped together as one medical or social condition. Rather, there is a progression from HIV infection to AIDS-related chronic illnesses to possible death, and livelihood strategies often alter along this HIV and AIDS time-line. Zimbabwe for over a decade now has gone through a series of economic and political crises which have impacted detrimentally on both urban and rural livelihoods, even for those households which are not directly affected by the HIV and AIDS pandemic. With the economy in free-fall, households have had to pursue a range of livelihood strategies in order to sustain themselves. These socio-economic conditions have in many ways facilitated susceptibility to HIV infection and vulnerability to AIDS. Many studies have examined this in relation to wellentrenched and stable communities in rural Zimbabwe. But the livelihood dynamics for such communities are significantly different to more unstable and informal settlements like Chivanhu, as thesis seeks to show. At the same time, the thesis offers a longitudinal study which is able to map the changes to the livelihoods of infected and affected households in Chivanhu. Though recognising the debilitating effects of the pandemic on these households, it also raises questions about the possible resilience of certain households despite great adversity. In doing so, it goes beyond the individual and household levels of analysis to consider the role of clusters (or groups of households) in responding to the impacts of HIV and AIDS. In this regard, particular emphasis is placed on gender and orphanhood. In the end, the thesis offers a nuanced analysis of the everyday complexities and challenges for affected households in a marginalised and informal rural community in Zimbabwe and thereby makes a contribution to re-theorising HIV and AIDS and rural livelihoods more broadly.
- Full Text:
- Authors: Makonese, Loveness
- Date: 2013
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3337 , http://hdl.handle.net/10962/d1003744
- Description: This thesis seeks to understand and analyse HIV and AIDS and rural livelihoods in Zimbabwe with particular reference to an isolated and marginalised informal settlement called Chivanhu in Masvingo Province. The focus is specifically on questions around HIV susceptibility, AIDS vulnerability and household resilience. In this regard, it is important to recognise that HIV and AIDS cannot be lumped together as one medical or social condition. Rather, there is a progression from HIV infection to AIDS-related chronic illnesses to possible death, and livelihood strategies often alter along this HIV and AIDS time-line. Zimbabwe for over a decade now has gone through a series of economic and political crises which have impacted detrimentally on both urban and rural livelihoods, even for those households which are not directly affected by the HIV and AIDS pandemic. With the economy in free-fall, households have had to pursue a range of livelihood strategies in order to sustain themselves. These socio-economic conditions have in many ways facilitated susceptibility to HIV infection and vulnerability to AIDS. Many studies have examined this in relation to wellentrenched and stable communities in rural Zimbabwe. But the livelihood dynamics for such communities are significantly different to more unstable and informal settlements like Chivanhu, as thesis seeks to show. At the same time, the thesis offers a longitudinal study which is able to map the changes to the livelihoods of infected and affected households in Chivanhu. Though recognising the debilitating effects of the pandemic on these households, it also raises questions about the possible resilience of certain households despite great adversity. In doing so, it goes beyond the individual and household levels of analysis to consider the role of clusters (or groups of households) in responding to the impacts of HIV and AIDS. In this regard, particular emphasis is placed on gender and orphanhood. In the end, the thesis offers a nuanced analysis of the everyday complexities and challenges for affected households in a marginalised and informal rural community in Zimbabwe and thereby makes a contribution to re-theorising HIV and AIDS and rural livelihoods more broadly.
- Full Text:
Corporate social responsibility of private game reserves in the Eastern Cape Province
- Authors: Motala, Amina Sadiq
- Date: 2013
- Subjects: Social responsibility of busines -- South Africa -- Eastern Cape Game reserves -- South Africa -- Eastern Cape Ecotourism -- South Africa -- Eastern Cape Environmental responsibility -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1187 , http://hdl.handle.net/10962/d1004335
- Description: The primary aim of this research study was to determine the current state of practice of corporate social responsibility (CSR) within the ecotourism based private game reserve (PGR) industry in the Eastern Cape Province of South Africa. According to Carroll (1991) four kind of responsibilities constitute total CSR, namely economic, legal, ethical and philanthropic responsibilities. Given the context of this research a fifth responsibility concerning environmental responsibilities was added to Carroll 's (1991) pyramid ofCSR. A descriptive and illustrative case study approach, within the phenomenological research paradigm, was used for the purpose of this research. The unit of analysis is the Indalo group, the Association of Eastern Cape Private Game Reserves, made up of 12 ecotourism based PORs. As the current research focused on eight of the twelve PGRs a mUltiple case study was employed. To give effect to the aim a number of research objectives were identified. Firstly to desclibe and assess the current practice in implementing CSR within the ecotourism based PGR industry in the Eastern Cape Province. Secondly, to assess and evaluate the involvement of ecotourism based PGRs in the Eastern Cape Province in each of the five responsibilities comprising CSR. Thirdly, to identify the challenges faced by ecotourism based PGRs in the Eastern Cape Province with regard to the implementation of CSR initiatives. Lastly to provide pertinent conclusions and recommendations with regard to CSR strategies within the ecotourism based PGR industry in the Eastern Cape Province. Data were collected by means of in-depth interviews with the managers of each reserve. In addition the researcher conducted focus interviews with administrative employees at each of the member reserves of the Indalo group. Additionally the managers of each reserve were requested to respond to a structured five point Likert scale questionnaire based on the research by Aupperle, Carroll and Hatfield (1985). This research study found that the current practice at the Indalo group is towards a strategic, long term approach to CSR that aids in the development of a 'sustainable organisation.' The aspect of ' empowerment' emerged as the essence of the current practice ofCSR of the Indalo group. Based on the current practice it was concluded that the Indalo group is actively involved in the specific components of CSR namely, environmental, economic, legal, ethical and philanthropic responsibilities. With regard to the environmental responsibilities it was concluded that the environment is the foundation upon which all other components of CSR rest. In addition it was concluded that the economic responsibilities, if managed well, are key to unlocking the CSR potential of a reserve as well as ensuring widespread economic development. In terms of the legal and ethical responsibilities it was concluded that tourism policies both at the national and international level have not aided in the development of a CSR agenda of the Indalo group. Furthermore managers of the reserves have been instrumental in cultivating their own legal culture of CSR based on their experience in the tourism industry and their ethical stances. In terms of the philanthropic responsibilities it can be concluded that charitable activities that are long term and strategic in nature allow for direct and indirect benefits to all parties involved. Overall, it can further be concluded that despite Hudson and Miller's (2005:5) view that the "tourism industry is well hehind other industries in terms of CSR" the Indalo group is moving forward in terms of rooting CSR into their everyday operations.
- Full Text:
- Authors: Motala, Amina Sadiq
- Date: 2013
- Subjects: Social responsibility of busines -- South Africa -- Eastern Cape Game reserves -- South Africa -- Eastern Cape Ecotourism -- South Africa -- Eastern Cape Environmental responsibility -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1187 , http://hdl.handle.net/10962/d1004335
- Description: The primary aim of this research study was to determine the current state of practice of corporate social responsibility (CSR) within the ecotourism based private game reserve (PGR) industry in the Eastern Cape Province of South Africa. According to Carroll (1991) four kind of responsibilities constitute total CSR, namely economic, legal, ethical and philanthropic responsibilities. Given the context of this research a fifth responsibility concerning environmental responsibilities was added to Carroll 's (1991) pyramid ofCSR. A descriptive and illustrative case study approach, within the phenomenological research paradigm, was used for the purpose of this research. The unit of analysis is the Indalo group, the Association of Eastern Cape Private Game Reserves, made up of 12 ecotourism based PORs. As the current research focused on eight of the twelve PGRs a mUltiple case study was employed. To give effect to the aim a number of research objectives were identified. Firstly to desclibe and assess the current practice in implementing CSR within the ecotourism based PGR industry in the Eastern Cape Province. Secondly, to assess and evaluate the involvement of ecotourism based PGRs in the Eastern Cape Province in each of the five responsibilities comprising CSR. Thirdly, to identify the challenges faced by ecotourism based PGRs in the Eastern Cape Province with regard to the implementation of CSR initiatives. Lastly to provide pertinent conclusions and recommendations with regard to CSR strategies within the ecotourism based PGR industry in the Eastern Cape Province. Data were collected by means of in-depth interviews with the managers of each reserve. In addition the researcher conducted focus interviews with administrative employees at each of the member reserves of the Indalo group. Additionally the managers of each reserve were requested to respond to a structured five point Likert scale questionnaire based on the research by Aupperle, Carroll and Hatfield (1985). This research study found that the current practice at the Indalo group is towards a strategic, long term approach to CSR that aids in the development of a 'sustainable organisation.' The aspect of ' empowerment' emerged as the essence of the current practice ofCSR of the Indalo group. Based on the current practice it was concluded that the Indalo group is actively involved in the specific components of CSR namely, environmental, economic, legal, ethical and philanthropic responsibilities. With regard to the environmental responsibilities it was concluded that the environment is the foundation upon which all other components of CSR rest. In addition it was concluded that the economic responsibilities, if managed well, are key to unlocking the CSR potential of a reserve as well as ensuring widespread economic development. In terms of the legal and ethical responsibilities it was concluded that tourism policies both at the national and international level have not aided in the development of a CSR agenda of the Indalo group. Furthermore managers of the reserves have been instrumental in cultivating their own legal culture of CSR based on their experience in the tourism industry and their ethical stances. In terms of the philanthropic responsibilities it can be concluded that charitable activities that are long term and strategic in nature allow for direct and indirect benefits to all parties involved. Overall, it can further be concluded that despite Hudson and Miller's (2005:5) view that the "tourism industry is well hehind other industries in terms of CSR" the Indalo group is moving forward in terms of rooting CSR into their everyday operations.
- Full Text:
Counting planes
- Authors: Rawlins, Isabel Bethan
- Date: 2013
- Subjects: Prose poems , Flash fiction , Short stories , English , Creative writing (Higher education) , Short stories, South African (English) -- 21st century , South African fiction (English) -- 21st century , South African poetry (English) -- 21st century , English language -- Writing
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5966 , http://hdl.handle.net/10962/d1001816
- Description: This collection of prose-poems and flash fiction, together with a few short stories, shows how romantic relationships colour our perspectives on the world. The collection has echoes throughout of speakers' voices, theme, imagery and tone. There is a narrative logic too, but working on a subtle level of echo and resonance
- Full Text:
- Authors: Rawlins, Isabel Bethan
- Date: 2013
- Subjects: Prose poems , Flash fiction , Short stories , English , Creative writing (Higher education) , Short stories, South African (English) -- 21st century , South African fiction (English) -- 21st century , South African poetry (English) -- 21st century , English language -- Writing
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5966 , http://hdl.handle.net/10962/d1001816
- Description: This collection of prose-poems and flash fiction, together with a few short stories, shows how romantic relationships colour our perspectives on the world. The collection has echoes throughout of speakers' voices, theme, imagery and tone. There is a narrative logic too, but working on a subtle level of echo and resonance
- Full Text:
Creating a new declaration of rights : a critical reconstruction of earth jurisprudence's global legislative framework
- Authors: Lenferna, Georges Alexandre
- Date: 2013
- Subjects: Universal Declaration , Rights , Earth , Environment , Ethics , Environmental law, International -- Research , Environmental law, International -- Philosophy , Environmental ethics -- Research , Nature conservation -- Law and legislation -- Research , Jurisprudence -- Research , Law -- Philosophy
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2704 , http://hdl.handle.net/10962/d1001979
- Description: This thesis aims to critique the Universal Declaration of the Rights of Mother Earth and its underlying moral justification in order to provide a stronger and improved version of both. In Chapter 1 I explore what sort of moral justification is necessary to establish the Universal Declaration on firm grounds and explore its relation to environmental ethics and rights discourse. I argue that a non-anthropocentric perspective is necessary to justify the Universal Declaration’s rights. In Chapter 2 I explore the underlying justification of the Universal Declaration as discovered in the works of Cormac Cullinan and Father Thomas Berry. I argue that their ethical framework is indeterminate, has many ambiguities and uncertainties, and, among other problems, it does not provide a clear action-guiding framework. In Chapter 3 I develop an alternative justification for the Universal Declaration. I argue against many predominant moral theories, that in light of our best scientific and moral understanding we should expand the realm of moral concern to include all living beings, a moral theory I call Life’s Imperative. In Chapter 4 I illustrate that Life’s Imperative is a much stronger, more coherent justification for the Universal Declaration, one that coheres with both our best understanding of the natural world and our relation to it, and to an environmental ethic reflective of that relationship. Unfortunately many of the weaknesses in the current implicit justification of the Universal Declaration have also led to it enshrining rights that are themselves problematic. In order to address these issues, I revise its rights to accord with the stronger justification that I established in Chapter 3. The end result of doing so is a revised version of the Universal Declaration
- Full Text:
- Authors: Lenferna, Georges Alexandre
- Date: 2013
- Subjects: Universal Declaration , Rights , Earth , Environment , Ethics , Environmental law, International -- Research , Environmental law, International -- Philosophy , Environmental ethics -- Research , Nature conservation -- Law and legislation -- Research , Jurisprudence -- Research , Law -- Philosophy
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2704 , http://hdl.handle.net/10962/d1001979
- Description: This thesis aims to critique the Universal Declaration of the Rights of Mother Earth and its underlying moral justification in order to provide a stronger and improved version of both. In Chapter 1 I explore what sort of moral justification is necessary to establish the Universal Declaration on firm grounds and explore its relation to environmental ethics and rights discourse. I argue that a non-anthropocentric perspective is necessary to justify the Universal Declaration’s rights. In Chapter 2 I explore the underlying justification of the Universal Declaration as discovered in the works of Cormac Cullinan and Father Thomas Berry. I argue that their ethical framework is indeterminate, has many ambiguities and uncertainties, and, among other problems, it does not provide a clear action-guiding framework. In Chapter 3 I develop an alternative justification for the Universal Declaration. I argue against many predominant moral theories, that in light of our best scientific and moral understanding we should expand the realm of moral concern to include all living beings, a moral theory I call Life’s Imperative. In Chapter 4 I illustrate that Life’s Imperative is a much stronger, more coherent justification for the Universal Declaration, one that coheres with both our best understanding of the natural world and our relation to it, and to an environmental ethic reflective of that relationship. Unfortunately many of the weaknesses in the current implicit justification of the Universal Declaration have also led to it enshrining rights that are themselves problematic. In order to address these issues, I revise its rights to accord with the stronger justification that I established in Chapter 3. The end result of doing so is a revised version of the Universal Declaration
- Full Text:
Critical studies in carbon electrode materials with applications in the electroanalysis of the mycotoxin citrinin
- Authors: Niland, Michael John
- Date: 2013
- Subjects: Electrodes, Carbon , Mycotoxins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4555 , http://hdl.handle.net/10962/d1018256
- Description: Guided by increasing legislation, the analysis of food borne toxins, including mycotoxins, seeks to address market related demands for the development of analytical systems to monitor this threat to food security and human health. This Thesis is directed at the assessment of the application of electrochemistry for direct electroanalysis and characterisation of the mycotoxin citrinin (CIT) in aqueous media as well as fundamental investigations of the surface of polished and oxidised glassy carbon electrodes (GCE). This study provides the first known account of CIT detection through electrochemical methods. Although electrochemically active, CIT current responses (Ip) were highly irreproducible at polished GCE with a coefficient of variation (C.V.) of 20.16 %. As stability of Ip across multiple electrode preparations is a key requirement in electroanalysis, investigations were directed at attaining stability in CIT Ip. Achieving stability in CIT Ip was investigated via two approaches, including: accounting for Ip variability between electrode preparations as a result of variable GCE surface conditions as a post-data-acquisition analysis and secondly, removing Ip variability through modification of GCE. Accounting for variability in Ip was investigated through the application of double layer capacitance as an indicator of the activity of an electrode, and in so doing serving as a relative mediator of Ip responses between electrodes. Application of this procedure dropped CIT C.V. to a third of starting value across polished GCE (C.V. = 7.18 %), chemically oxidised GCE (Pi-GCE, C.V = 8.47 %) and functionalised multi-walled carbon nanotube modified GCE (fMWCNT, C.V. = 25.79 %) and was effective with analysis of structurally distinct molecules, 2,4-dimethylaniline (2,4-DMA) and 1,2,4-trihydroxybenzene (Triol). Furthermore, it afforded the ability to determine discreet solution overlapping data sets of Ip. Stabilising Ip through GCE surface modification was achieved by anodic electro-oxidation of GCE and allowed for direct electroanalysis of CIT and subsequent characterisation and analysis of CIT in complex media as it reduced C.V. of CIT Ip to 0.73 %. Fundamental investigations of the electrode surface condition are described such that the source of variability could be identified and the interactions of CIT with the electrode understood. Two surface oxidation techniques were applied in modification of GCE; anodic electro-oxidation (EOx GCE) and chemical oxidation using piranha solution (Pi-GCE), analysis of which has previously not been reported. Fundamental analyses to determine surface morphology and chemistry of Pi-GCE, EOx-GCE and polished GCE were conducted using high resolution scanning electron microscopy (HRSEM), scanning electrochemical microscopy (SECM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR) and via electroanalytical methods. These studies showed that both oxidation procedures introduced a variety of oxide species at GCE surface, and further that the extent of those species was similar with total % O being 27.67 % and 33.47 % at Pi-GCE and EOx-GCE respectively. Although chemically similar, each surface was morphologically distinct. Electrochemical analyses at the surfaces revealed Pi-GCE to behave more similarly to polished GCE than EOx-GCE. As CIT responses were found to be stable at EOx-GCE (C.V. = 0.73 %) as opposed to Pi-GCE (C.V. = 22.87 %), stability of CIT Ip was likely to be as a result of a physical interaction with electrode morphology rather than interaction on a chemical basis. Morphological analyses revealed polished GCE and Pi-GCE to be highly morphologically irregular at the micro-scale. Although comparatively smooth, the surface morphology of EOx-GCE does not account for the stability of Ip. This study thus proposed a theory to describe the mechanism by which the limited conductivity and porosity of EOx-GCE allow for it to provide a relatively stable surface area within the oxide layer, adjacent to the electrode surface, and thus provided a stable platform for electroanalysis. Voltammetric characterization of CIT at EOx-GCE revealed that anodic oxidation in aqueous media involved an uneven number of electrons to protons via an ECE mechanism. This was illustrated to be nt = 2e- accompanied by the transfer of 1H⁺ per molecule oxidised. A proposed reaction scheme for the initial stages of CIT oxidation was suggested to involve both hydroxyl and carboxyl moieties of the CIT molecule. CIT oxidation was shown to arise as a result of a relatively complex mass transport regime which included both adsorptive and diffusive derived Ip₁. The LOD in buffered aqueous media was found to be 16 nM, a highly competitive result in relation to chromatographic techniques. Further application of EOx-GCE in complex media illustrated that CIT associates non-specifically with the components of food samples, primarily proteins. As a result of this, extraction of CIT from such media is mandatory. Liquid-liquid extraction illustrated a recovery in CIT Ip₁ and in so doing provided a means of accurately and sensitively detecting CIT from food samples with an LOD of 20 nM. These responses were corroborated by HPLC analyses on the same extractions and illustrate the applicability of electroanalysis as an analytical technique.
- Full Text:
- Authors: Niland, Michael John
- Date: 2013
- Subjects: Electrodes, Carbon , Mycotoxins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4555 , http://hdl.handle.net/10962/d1018256
- Description: Guided by increasing legislation, the analysis of food borne toxins, including mycotoxins, seeks to address market related demands for the development of analytical systems to monitor this threat to food security and human health. This Thesis is directed at the assessment of the application of electrochemistry for direct electroanalysis and characterisation of the mycotoxin citrinin (CIT) in aqueous media as well as fundamental investigations of the surface of polished and oxidised glassy carbon electrodes (GCE). This study provides the first known account of CIT detection through electrochemical methods. Although electrochemically active, CIT current responses (Ip) were highly irreproducible at polished GCE with a coefficient of variation (C.V.) of 20.16 %. As stability of Ip across multiple electrode preparations is a key requirement in electroanalysis, investigations were directed at attaining stability in CIT Ip. Achieving stability in CIT Ip was investigated via two approaches, including: accounting for Ip variability between electrode preparations as a result of variable GCE surface conditions as a post-data-acquisition analysis and secondly, removing Ip variability through modification of GCE. Accounting for variability in Ip was investigated through the application of double layer capacitance as an indicator of the activity of an electrode, and in so doing serving as a relative mediator of Ip responses between electrodes. Application of this procedure dropped CIT C.V. to a third of starting value across polished GCE (C.V. = 7.18 %), chemically oxidised GCE (Pi-GCE, C.V = 8.47 %) and functionalised multi-walled carbon nanotube modified GCE (fMWCNT, C.V. = 25.79 %) and was effective with analysis of structurally distinct molecules, 2,4-dimethylaniline (2,4-DMA) and 1,2,4-trihydroxybenzene (Triol). Furthermore, it afforded the ability to determine discreet solution overlapping data sets of Ip. Stabilising Ip through GCE surface modification was achieved by anodic electro-oxidation of GCE and allowed for direct electroanalysis of CIT and subsequent characterisation and analysis of CIT in complex media as it reduced C.V. of CIT Ip to 0.73 %. Fundamental investigations of the electrode surface condition are described such that the source of variability could be identified and the interactions of CIT with the electrode understood. Two surface oxidation techniques were applied in modification of GCE; anodic electro-oxidation (EOx GCE) and chemical oxidation using piranha solution (Pi-GCE), analysis of which has previously not been reported. Fundamental analyses to determine surface morphology and chemistry of Pi-GCE, EOx-GCE and polished GCE were conducted using high resolution scanning electron microscopy (HRSEM), scanning electrochemical microscopy (SECM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR) and via electroanalytical methods. These studies showed that both oxidation procedures introduced a variety of oxide species at GCE surface, and further that the extent of those species was similar with total % O being 27.67 % and 33.47 % at Pi-GCE and EOx-GCE respectively. Although chemically similar, each surface was morphologically distinct. Electrochemical analyses at the surfaces revealed Pi-GCE to behave more similarly to polished GCE than EOx-GCE. As CIT responses were found to be stable at EOx-GCE (C.V. = 0.73 %) as opposed to Pi-GCE (C.V. = 22.87 %), stability of CIT Ip was likely to be as a result of a physical interaction with electrode morphology rather than interaction on a chemical basis. Morphological analyses revealed polished GCE and Pi-GCE to be highly morphologically irregular at the micro-scale. Although comparatively smooth, the surface morphology of EOx-GCE does not account for the stability of Ip. This study thus proposed a theory to describe the mechanism by which the limited conductivity and porosity of EOx-GCE allow for it to provide a relatively stable surface area within the oxide layer, adjacent to the electrode surface, and thus provided a stable platform for electroanalysis. Voltammetric characterization of CIT at EOx-GCE revealed that anodic oxidation in aqueous media involved an uneven number of electrons to protons via an ECE mechanism. This was illustrated to be nt = 2e- accompanied by the transfer of 1H⁺ per molecule oxidised. A proposed reaction scheme for the initial stages of CIT oxidation was suggested to involve both hydroxyl and carboxyl moieties of the CIT molecule. CIT oxidation was shown to arise as a result of a relatively complex mass transport regime which included both adsorptive and diffusive derived Ip₁. The LOD in buffered aqueous media was found to be 16 nM, a highly competitive result in relation to chromatographic techniques. Further application of EOx-GCE in complex media illustrated that CIT associates non-specifically with the components of food samples, primarily proteins. As a result of this, extraction of CIT from such media is mandatory. Liquid-liquid extraction illustrated a recovery in CIT Ip₁ and in so doing provided a means of accurately and sensitively detecting CIT from food samples with an LOD of 20 nM. These responses were corroborated by HPLC analyses on the same extractions and illustrate the applicability of electroanalysis as an analytical technique.
- Full Text:
Deploying DNSSEC in islands of security
- Authors: Murisa, Wesley Vengayi
- Date: 2013 , 2013-03-31
- Subjects: Internet domain names , Computer security , Computer network protocols , Computer security -- Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4577 , http://hdl.handle.net/10962/d1003053 , Internet domain names , Computer security , Computer network protocols , Computer security -- Africa
- Description: The Domain Name System (DNS), a name resolution protocol is one of the vulnerable network protocols that has been subjected to many security attacks such as cache poisoning, denial of service and the 'Kaminsky' spoofing attack. When DNS was designed, security was not incorporated into its design. The DNS Security Extensions (DNSSEC) provides security to the name resolution process by using public key cryptosystems. Although DNSSEC has backward compatibility with unsecured zones, it only offers security to clients when communicating with security aware zones. Widespread deployment of DNSSEC is therefore necessary to secure the name resolution process and provide security to the Internet. Only a few Top Level Domains (TLD's) have deployed DNSSEC, this inherently makes it difficult for their sub-domains to implement the security extensions to the DNS. This study analyses mechanisms that can be used by domains in islands of security to deploy DNSSEC so that the name resolution process can be secured in two specific cases where either the TLD is not signed or the domain registrar is not able to support signed domains. The DNS client side mechanisms evaluated in this study include web browser plug-ins, local validating resolvers and domain look-aside validation. The results of the study show that web browser plug-ins cannot work on their own without local validating resolvers. The web browser validators, however, proved to be useful in indicating to the user whether a domain has been validated or not. Local resolvers present a more secure option for Internet users who cannot trust the communication channel between their stub resolvers and remote name servers. However, they do not provide a way of showing the user whether a domain name has been correctly validated or not. Based on the results of the tests conducted, it is recommended that local validators be used with browser validators for visibility and improved security. On the DNS server side, Domain Look-aside Validation (DLV) presents a viable alternative for organizations in islands of security like most countries in Africa where only two country code Top Level Domains (ccTLD) have deployed DNSSEC. This research recommends use of DLV by corporates to provide DNS security to both internal and external users accessing their web based services. , LaTeX with hyperref package , pdfTeX-1.40.10
- Full Text:
- Authors: Murisa, Wesley Vengayi
- Date: 2013 , 2013-03-31
- Subjects: Internet domain names , Computer security , Computer network protocols , Computer security -- Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4577 , http://hdl.handle.net/10962/d1003053 , Internet domain names , Computer security , Computer network protocols , Computer security -- Africa
- Description: The Domain Name System (DNS), a name resolution protocol is one of the vulnerable network protocols that has been subjected to many security attacks such as cache poisoning, denial of service and the 'Kaminsky' spoofing attack. When DNS was designed, security was not incorporated into its design. The DNS Security Extensions (DNSSEC) provides security to the name resolution process by using public key cryptosystems. Although DNSSEC has backward compatibility with unsecured zones, it only offers security to clients when communicating with security aware zones. Widespread deployment of DNSSEC is therefore necessary to secure the name resolution process and provide security to the Internet. Only a few Top Level Domains (TLD's) have deployed DNSSEC, this inherently makes it difficult for their sub-domains to implement the security extensions to the DNS. This study analyses mechanisms that can be used by domains in islands of security to deploy DNSSEC so that the name resolution process can be secured in two specific cases where either the TLD is not signed or the domain registrar is not able to support signed domains. The DNS client side mechanisms evaluated in this study include web browser plug-ins, local validating resolvers and domain look-aside validation. The results of the study show that web browser plug-ins cannot work on their own without local validating resolvers. The web browser validators, however, proved to be useful in indicating to the user whether a domain has been validated or not. Local resolvers present a more secure option for Internet users who cannot trust the communication channel between their stub resolvers and remote name servers. However, they do not provide a way of showing the user whether a domain name has been correctly validated or not. Based on the results of the tests conducted, it is recommended that local validators be used with browser validators for visibility and improved security. On the DNS server side, Domain Look-aside Validation (DLV) presents a viable alternative for organizations in islands of security like most countries in Africa where only two country code Top Level Domains (ccTLD) have deployed DNSSEC. This research recommends use of DLV by corporates to provide DNS security to both internal and external users accessing their web based services. , LaTeX with hyperref package , pdfTeX-1.40.10
- Full Text:
Describing the relationship between the cognitive and linguistic complexity of a mathematical literacy examination and types of student errors
- Authors: Vale, Pamela
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Research -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa -- Evaluation Mathematics -- Study and teaching (Secondary) -- South Africa -- Evaluation Communication in foreign language education -- Research -- South Africa Communication in foreign language education -- Research -- South Africa Education, Secondary -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1397 , http://hdl.handle.net/10962/d1001774
- Description: Much prior research has shown that if students have a poor command of the language in which they are taught and assessed, they experience a complex and deep learning disadvantage (Barton & Neville-Barton, 2003). Abedi (2006) mentions, in particular, that unnecessary linguistic complexity can threaten the validity of examination items and thus compromises the fairness of the assessment for English language learners. In Clarkson’s (1991, p. 31) research it was found that for the English language learners in the study “comprehension errors [made] up a high proportion of the errors made when…students attempt[ed] to solve mathematical word problems”. In an attempt to explore whether this was the case for a group of National Certificate (Vocational) [NC(V)] students at an FET college, the research conducted in this study focused on describing the cognitive and linguistic complexity of Level 4 Mathematical Literacy examination items as well as the types of responses from a sample of students. A mixed-methods case study design was selected. Student errors were classified as either due to mathematical literacy-related sources, or language-related sources and the question was asked as to how the cognitive and linguistic complexity of items might be related to the types of errors made. Statistically significant correlations were found between the linguistic complexity of items and language-related errors, and between the cognitive complexity of items and all types of errors. It was also possible to identify which language features, in particular, were statistically significantly correlated with linguistic complexity, namely: prepositional phrases; words of 7 letters or more and complex/compound sentences. As was expected, the majority of errors were categorised as mathematical literacy-related. However, as many as 19.22% of all errors made were identified as language-related. While the scope of the study prevents any generalisations from being made, the results indicate a need for a larger-scale study of this nature to determine if the complex and deep learning disadvantage mentioned by Barton and Neville-Barton (2003) does exist with regard to the assessment of Mathematical Literacy for NC(V) students who are English language learners (Barton & Neville-Barton, 2003).
- Full Text:
- Authors: Vale, Pamela
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Research -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa -- Evaluation Mathematics -- Study and teaching (Secondary) -- South Africa -- Evaluation Communication in foreign language education -- Research -- South Africa Communication in foreign language education -- Research -- South Africa Education, Secondary -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1397 , http://hdl.handle.net/10962/d1001774
- Description: Much prior research has shown that if students have a poor command of the language in which they are taught and assessed, they experience a complex and deep learning disadvantage (Barton & Neville-Barton, 2003). Abedi (2006) mentions, in particular, that unnecessary linguistic complexity can threaten the validity of examination items and thus compromises the fairness of the assessment for English language learners. In Clarkson’s (1991, p. 31) research it was found that for the English language learners in the study “comprehension errors [made] up a high proportion of the errors made when…students attempt[ed] to solve mathematical word problems”. In an attempt to explore whether this was the case for a group of National Certificate (Vocational) [NC(V)] students at an FET college, the research conducted in this study focused on describing the cognitive and linguistic complexity of Level 4 Mathematical Literacy examination items as well as the types of responses from a sample of students. A mixed-methods case study design was selected. Student errors were classified as either due to mathematical literacy-related sources, or language-related sources and the question was asked as to how the cognitive and linguistic complexity of items might be related to the types of errors made. Statistically significant correlations were found between the linguistic complexity of items and language-related errors, and between the cognitive complexity of items and all types of errors. It was also possible to identify which language features, in particular, were statistically significantly correlated with linguistic complexity, namely: prepositional phrases; words of 7 letters or more and complex/compound sentences. As was expected, the majority of errors were categorised as mathematical literacy-related. However, as many as 19.22% of all errors made were identified as language-related. While the scope of the study prevents any generalisations from being made, the results indicate a need for a larger-scale study of this nature to determine if the complex and deep learning disadvantage mentioned by Barton and Neville-Barton (2003) does exist with regard to the assessment of Mathematical Literacy for NC(V) students who are English language learners (Barton & Neville-Barton, 2003).
- Full Text:
Development of a novel, quantitative assay for determining the rate of activity of antimalarial drugs
- Authors: Khan, Tasmiyah
- Date: 2013
- Subjects: Assay , ATP , Antimalarials -- Therapeutic use Malaria Malaria -- Drug therapy Adenosine triphosphate Luciferases Plasmodium falciparum
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3884 , http://hdl.handle.net/10962/d1001618
- Description: Malaria, caused by an intracellular Plasmodium parasite, remains a devastating disease, having claimed approximately 655 000 lives worldwide in 2010. The Medicines for Malaria Venture suggests a "single-dose radical cure" as the ideal malaria treatment since rapid clearance of blood-stage parasites and symptom relief improves patient compliance and limits drug resistance. Thus, novel antimalarials should be rapid-acting and assessing their rate of activity is critical to drug discovery. Traditional evaluation of this rate by morphological assessments is flawed by highly subjective, operator-specific interpretations, mainly due to heterogeneous parasite morphology under routine culture conditions. This study aimed to develop an alternative, quantitative assay. Energy is vital for the growth and maintenance of all living organisms. Commercially available kits allow rapid quantification of the cell's energy currency, ATP. Therefore, quantification of parasite ATP shows potential for diagnosing abnormal parasite metabolism and the kinetics of drug action. In this study, a rapid protocol for detecting ATP in Plasmodium falciparum parasites using a luminescence-based kit was developed and optimised. Furthermore, luciferase-expressing transgenic parasites, in which luciferase activity is detected using a similar kit, were acquired. The utility of both methods for evaluating the rate of drug-induced stress was explored using antimalarials with varying modes of action and, presumably, rates of activity. Results showed that parasite ATP remained unchanged, increased or decreased during drug exposure. Morphological examinations by light microscopy and a Recovery assay, aided interpretation of the drug-induced changes in parasite ATP. These investigations suggested that unchanged parasite ATP levels reflect poor drug action, increased ATP levels indicate a stress response and partially compromised viability, while significantly reduced ATP reflects severely compromised viability. Concerning the Luciferase assay, parasite luciferase activity decreased during drug exposure, even in the presence of proteasome inhibitors. Changes in parasite ATP and luciferase activity occurred at rates which suggested that chloroquine is slow-acting, mefloquine has a moderate rate of activity and artemisinin is rapid-acting. These findings are compatible with the expected rates of activity of these established antimalarials. Hence, measurement of parasite ATP and/or luciferase activity may support assessments of parasite health and the kinetics of antimalarial action during drug discovery
- Full Text:
- Authors: Khan, Tasmiyah
- Date: 2013
- Subjects: Assay , ATP , Antimalarials -- Therapeutic use Malaria Malaria -- Drug therapy Adenosine triphosphate Luciferases Plasmodium falciparum
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3884 , http://hdl.handle.net/10962/d1001618
- Description: Malaria, caused by an intracellular Plasmodium parasite, remains a devastating disease, having claimed approximately 655 000 lives worldwide in 2010. The Medicines for Malaria Venture suggests a "single-dose radical cure" as the ideal malaria treatment since rapid clearance of blood-stage parasites and symptom relief improves patient compliance and limits drug resistance. Thus, novel antimalarials should be rapid-acting and assessing their rate of activity is critical to drug discovery. Traditional evaluation of this rate by morphological assessments is flawed by highly subjective, operator-specific interpretations, mainly due to heterogeneous parasite morphology under routine culture conditions. This study aimed to develop an alternative, quantitative assay. Energy is vital for the growth and maintenance of all living organisms. Commercially available kits allow rapid quantification of the cell's energy currency, ATP. Therefore, quantification of parasite ATP shows potential for diagnosing abnormal parasite metabolism and the kinetics of drug action. In this study, a rapid protocol for detecting ATP in Plasmodium falciparum parasites using a luminescence-based kit was developed and optimised. Furthermore, luciferase-expressing transgenic parasites, in which luciferase activity is detected using a similar kit, were acquired. The utility of both methods for evaluating the rate of drug-induced stress was explored using antimalarials with varying modes of action and, presumably, rates of activity. Results showed that parasite ATP remained unchanged, increased or decreased during drug exposure. Morphological examinations by light microscopy and a Recovery assay, aided interpretation of the drug-induced changes in parasite ATP. These investigations suggested that unchanged parasite ATP levels reflect poor drug action, increased ATP levels indicate a stress response and partially compromised viability, while significantly reduced ATP reflects severely compromised viability. Concerning the Luciferase assay, parasite luciferase activity decreased during drug exposure, even in the presence of proteasome inhibitors. Changes in parasite ATP and luciferase activity occurred at rates which suggested that chloroquine is slow-acting, mefloquine has a moderate rate of activity and artemisinin is rapid-acting. These findings are compatible with the expected rates of activity of these established antimalarials. Hence, measurement of parasite ATP and/or luciferase activity may support assessments of parasite health and the kinetics of antimalarial action during drug discovery
- Full Text:
Dog wars : a Victorian steampunk adventure
- Authors: Molino, Nicolene Chloe
- Date: 2013
- Subjects: Creative writing , Fiction , South Africa , Creative writing (Higher education) , Short stories, South African (English) -- 21st century , South African fiction (English) -- 21st century , English language -- Writing
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5965 , http://hdl.handle.net/10962/d1001815
- Description: We're in an alternate universe, circa Dickensian London. Leofric Lieven, a local crime lord, is about to find the past catching up on him. The Romany Carnival has come to town, and a gypsy woman, his former lover and partner in crime, demands from him a favour which will redress his betrayal of years before: he must secure a stolen object and return it to her. But things go horribly wrong when local delivery boy Cards Bennish is kidnapped by Leofric’s competitor before he can deliver the goods that will cover Leofric's debt to the gypsy. In this world, humans can shape shift into animals, entirely or only partially, dog fighting is the favourite pastime for high stakes betting, and power belongs to the highest bidder. The gypsy’s final bet, for the highest stakes yet, will seal the fates of a number of people, for better or worse
- Full Text:
- Authors: Molino, Nicolene Chloe
- Date: 2013
- Subjects: Creative writing , Fiction , South Africa , Creative writing (Higher education) , Short stories, South African (English) -- 21st century , South African fiction (English) -- 21st century , English language -- Writing
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5965 , http://hdl.handle.net/10962/d1001815
- Description: We're in an alternate universe, circa Dickensian London. Leofric Lieven, a local crime lord, is about to find the past catching up on him. The Romany Carnival has come to town, and a gypsy woman, his former lover and partner in crime, demands from him a favour which will redress his betrayal of years before: he must secure a stolen object and return it to her. But things go horribly wrong when local delivery boy Cards Bennish is kidnapped by Leofric’s competitor before he can deliver the goods that will cover Leofric's debt to the gypsy. In this world, humans can shape shift into animals, entirely or only partially, dog fighting is the favourite pastime for high stakes betting, and power belongs to the highest bidder. The gypsy’s final bet, for the highest stakes yet, will seal the fates of a number of people, for better or worse
- Full Text:
Drivers of macrophyte assemblages in South African freshwater systems
- Authors: Martin, Grant Douglas
- Date: 2013
- Subjects: Freshwater plants -- South Africa Aquatic weeds -- South Africa Invasive plants -- South Africa Freshwater ecology -- South Africa Biotic communities -- South Africa Maximum entropy method Lagarosiphon major -- South Africa Phytophagous insects -- South Africa Hydrellia -- South Africa Parasitoids -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5621 , http://hdl.handle.net/10962/d1004127
- Description: Potentially damaging submerged invasive freshwater macrophytes have been identified in South African freshwater systems, but have received less attention than their floating counterparts. To ascertain the changes and effects that these species may have on macrophyte ecology, an understanding of the drivers of macrophyte assemblages is essential. The aims of this thesis were to investigate select abiotic and biotic factors driving introduction, establishment and spread of submerged macrophytes in South Africa. Surveys on the status of submerged plant species in South Africa were conducted to find out the distribution and diversity of the species present, imported to, and traded in South Africa. Numerous submerged indigenous and invasive macrophyte locality records were collected during field surveys, of which many were first time records. Pet stores and aquarist trading activities were identified as potential vectors for the spread of submerged macrophytes through online surveys and personal interviews. These results highlighted the potential these species have for continuing to enter, and spread within South African water bodies. Maximum Entropy (MAXENT) is a general-purpose method used to predict or infer distributions from incomplete information, and was used here to predict areas suitable for the establishment of five of these invasive macrophytes. Many systems throughout South Africa, particularly those in the subtropical coastal regions, were found to be climatically suitable for the establishment of Elodea canadensis Michx., Egeria densa Planch., Hydrilla verticillata (L.f.) Royle (all Hydrocharitaceae), Myriophyllum spicatum L. (Haloragaceae), and Cabomba caroliniana Gray (Cabombaceae). Despite the high probability of invasion, facilitated by vectors and suitable climate, South Africa’s rich indigenous submerged aquatic flora may be preventing the establishment of these submerged invasive species. Studies on the competitive interactions between a common indigenous submerged macrophytes, Lagarosiphon major (Roxb.) (Hydrocharitaceae) and M.spicatum, an invasive native to Eurasia, were conducted to ascertain which conditions influence competitive superiority. High sediment nutrient conditions significantly increased the growth rate and competitive ability of both species, while clay sediments significantly increased the competitive ability of L. major over M. spicatum, but sandy sediments improved the competitive ability of M. spicatum. These results highlighted the dynamic changes in competition between submerged species driven by abiotic factors, but did not take into consideration the effect that herbivory, a biotic factor, could have on competition between the two species. The effect of herbivory by phytophagous insects of submerged plant species has been regarded as negligible. To find out what this effect is, multiple field surveys were undertaken throughout South Africa to find natural enemies of indigenous Lagarosiphon species with the aim of identifying such species, and quantifying their influence on plant growth dynamics. Several new phytophagous species were recorded for the first time. An ephydrid fly, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae) was ascertained to be the most ubiquitous and abundant species associated with L. major in South Africa. The influence of herbivory by this fly on the competitive ability of L. major in the presence of M. spicatum was investigated using an inverse linear model, which showed that herbivory by H. lagarosiphon reduced the competitive ability of L. major by approximately five times in favour of M. spicatum. This study served to highlight the importance of herbivory as a driver of submerged aquatic plant dynamics. Current ecological theory emphasises the importance of investigating beyond plant-herbivore interactions, by including multitrophic interactions in community dynamics. Therefore, the potential of parasitism by a parasitoid wasp, Chaenusa luteostigma sp. n. Achterberg (Hymenoptera: Braconidae: Alysiinae) on H. lagarosiphon to shift the competitive interactions between the two plant species was also examined. The addition of the parasitoid reduced the effect of herbivory by the fly on L. major by half, thereby shifting the competitive balance in favour of L. major over M. spicatum. This study provides valuable insight into a selection of drivers of submerged macrophyte assemblages of South Africa. It highlights the precarious position of South African freshwater systems with regard to the potential invasion by damaging submerged invasive species. It also provides interesting insights into the effect of competition, herbivory and parasitism on the establishment and spread of species within submerged freshwater systems. Understanding the different influences could assist managers and policy makers to make validated decisions ensuring the integrity of South African freshwater systems.
- Full Text:
- Authors: Martin, Grant Douglas
- Date: 2013
- Subjects: Freshwater plants -- South Africa Aquatic weeds -- South Africa Invasive plants -- South Africa Freshwater ecology -- South Africa Biotic communities -- South Africa Maximum entropy method Lagarosiphon major -- South Africa Phytophagous insects -- South Africa Hydrellia -- South Africa Parasitoids -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5621 , http://hdl.handle.net/10962/d1004127
- Description: Potentially damaging submerged invasive freshwater macrophytes have been identified in South African freshwater systems, but have received less attention than their floating counterparts. To ascertain the changes and effects that these species may have on macrophyte ecology, an understanding of the drivers of macrophyte assemblages is essential. The aims of this thesis were to investigate select abiotic and biotic factors driving introduction, establishment and spread of submerged macrophytes in South Africa. Surveys on the status of submerged plant species in South Africa were conducted to find out the distribution and diversity of the species present, imported to, and traded in South Africa. Numerous submerged indigenous and invasive macrophyte locality records were collected during field surveys, of which many were first time records. Pet stores and aquarist trading activities were identified as potential vectors for the spread of submerged macrophytes through online surveys and personal interviews. These results highlighted the potential these species have for continuing to enter, and spread within South African water bodies. Maximum Entropy (MAXENT) is a general-purpose method used to predict or infer distributions from incomplete information, and was used here to predict areas suitable for the establishment of five of these invasive macrophytes. Many systems throughout South Africa, particularly those in the subtropical coastal regions, were found to be climatically suitable for the establishment of Elodea canadensis Michx., Egeria densa Planch., Hydrilla verticillata (L.f.) Royle (all Hydrocharitaceae), Myriophyllum spicatum L. (Haloragaceae), and Cabomba caroliniana Gray (Cabombaceae). Despite the high probability of invasion, facilitated by vectors and suitable climate, South Africa’s rich indigenous submerged aquatic flora may be preventing the establishment of these submerged invasive species. Studies on the competitive interactions between a common indigenous submerged macrophytes, Lagarosiphon major (Roxb.) (Hydrocharitaceae) and M.spicatum, an invasive native to Eurasia, were conducted to ascertain which conditions influence competitive superiority. High sediment nutrient conditions significantly increased the growth rate and competitive ability of both species, while clay sediments significantly increased the competitive ability of L. major over M. spicatum, but sandy sediments improved the competitive ability of M. spicatum. These results highlighted the dynamic changes in competition between submerged species driven by abiotic factors, but did not take into consideration the effect that herbivory, a biotic factor, could have on competition between the two species. The effect of herbivory by phytophagous insects of submerged plant species has been regarded as negligible. To find out what this effect is, multiple field surveys were undertaken throughout South Africa to find natural enemies of indigenous Lagarosiphon species with the aim of identifying such species, and quantifying their influence on plant growth dynamics. Several new phytophagous species were recorded for the first time. An ephydrid fly, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae) was ascertained to be the most ubiquitous and abundant species associated with L. major in South Africa. The influence of herbivory by this fly on the competitive ability of L. major in the presence of M. spicatum was investigated using an inverse linear model, which showed that herbivory by H. lagarosiphon reduced the competitive ability of L. major by approximately five times in favour of M. spicatum. This study served to highlight the importance of herbivory as a driver of submerged aquatic plant dynamics. Current ecological theory emphasises the importance of investigating beyond plant-herbivore interactions, by including multitrophic interactions in community dynamics. Therefore, the potential of parasitism by a parasitoid wasp, Chaenusa luteostigma sp. n. Achterberg (Hymenoptera: Braconidae: Alysiinae) on H. lagarosiphon to shift the competitive interactions between the two plant species was also examined. The addition of the parasitoid reduced the effect of herbivory by the fly on L. major by half, thereby shifting the competitive balance in favour of L. major over M. spicatum. This study provides valuable insight into a selection of drivers of submerged macrophyte assemblages of South Africa. It highlights the precarious position of South African freshwater systems with regard to the potential invasion by damaging submerged invasive species. It also provides interesting insights into the effect of competition, herbivory and parasitism on the establishment and spread of species within submerged freshwater systems. Understanding the different influences could assist managers and policy makers to make validated decisions ensuring the integrity of South African freshwater systems.
- Full Text: