Land rental policy and land market in Mashonaland East Province, Zimbabwe: implications on farmer decisions, efficiency and equity under A1 and A2 models
- Authors: Tatsvarei , Simbarashe
- Date: 2019
- Subjects: Farms, Small Agricultural extension work
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15666 , vital:40501
- Description: Government promulgated the land rental policy starting in the year 2007. The policy required that A1 (market residual) and A2 (indigenous commercial) farmers pay rentals to the state. Since then, there has also been an emerging trend in which farmers have been renting in and out land, resulting in an informal market for land rentals. The study therefore assessed farmers’ perceptions of land rental policy and evaluated the possible association of this policy to farmers’ decision making on land rental markets as well as its implications on farmers’ efficiency and equity. The study was carried out in Mashonaland East Province of Zimbabwe, covering two districts, Goromonzi and Marondera. The focus was specifically on A1 and A2 farmers, as the rental policy was directed at these resettlement models only and much of the informal land rental markets were prevalent among these categories of farmers. Data collection utilised the survey approach. This was supported by key informant interviews and focus group discussions, with a final sample of 339 households selected using multi-stage sampling method. Survey data were transcribed on CsPro 6, and analysed using Stata, SPSS and Frontier 4.1. Results showed that about a third of household respondents was from Marondera and twothirds was from Goromonzi, while 79% and 21% was A1 and A2 farmers respectively. About 80% was male headed households and the remainder was female headed households. About half of the households were not participating in land rental markets while the other half was split almost equally between those renting-in and renting-out land. In general, A2 farmers were better in agricultural productivity than A1 farmers. It was concluded that farmers had a fairly good knowledge of the agricultural land rental policy enunciated in the Finance Bills. A1 farmers were more knowledgeable than A2 farmers, but no vii significant differences were observed between male and female headed households and farmers involved and not involved in land rental markets. Farmers’ attitudes in relation to policy were categorised as fair, with significant differences based on gender and land market participation. Practice scores showed a poor adherence to policy for all categories of farmers. Overall perceptions of farmers on rental policy was inferred as fair with significant differences existing between land rental market participants and non-participants (autarky). The results of a bivariate Tobit model results showed that the decision to rent-in land was significantly influenced by gender, household income, permanent labour, cultivated area, tenure certainty, irrigable land size and crop diversification. On the other hand, age, permanent labour, irrigable land size and crop diversification significantly influenced farmers’ decisions to rent-out land. The conclusion was that household characteristics, land endowments and transaction costs significantly influenced the decision to rent-in land while the former two were strong in influencing renting-out decisions. Results from the linearized Cobb Douglas model showed that economic efficiency for most farmers was above 50%. Farmers renting-out land under A1 were found to be the most economically efficient, followed by those who were renting-in and least efficient were farmers not participating in land rental markets, though the differences were marginal. For the A2 model, renting-in farmers were the most efficient, followed by those in autarky position, while renting-out farmers were the least. Overall, the most efficient farmers were those renting-in, followed by those renting-out while farmers in autarky were the least efficient. Overall efficiency was higher for A2 farmers than for A1 farmers. For farmers not participating in rental markets, the sources of inefficiency were crop type, crop area and labour. For farmers renting-in, it was proportion of irrigable land, size of irrigable land, crop type, crop area and viii labour, while inefficiency drivers for renting-out farmers were crop type and associated area. Equity analysis showed that participation in land rental markets reduced inequality for farmers in the two districts and male and female headed households. Inequality was increased among A1 farmers and remained unchanged among A2 farmers. Overall, the emerging position was that participation in land rental markets resulted in higher efficiency and reduced inequality in land holding among the sampled farmers. It is recommended that government should be consistent on land rental policy and bring into place effective administration of land rental policy. Government may also consider formal acceptance of land rental markets in light of the marginal efficiency and equity benefits shown in the study. However, formalizing land rental markets alone may not be a panacea to improved efficiency and needs to be supported by other productivity measures given the average efficiency values for farmers. Crop and livestock production based on compatibility with the natural regions and defined minimum size of land should be encouraged to improve efficiency
- Full Text:
- Date Issued: 2019
- Authors: Tatsvarei , Simbarashe
- Date: 2019
- Subjects: Farms, Small Agricultural extension work
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15666 , vital:40501
- Description: Government promulgated the land rental policy starting in the year 2007. The policy required that A1 (market residual) and A2 (indigenous commercial) farmers pay rentals to the state. Since then, there has also been an emerging trend in which farmers have been renting in and out land, resulting in an informal market for land rentals. The study therefore assessed farmers’ perceptions of land rental policy and evaluated the possible association of this policy to farmers’ decision making on land rental markets as well as its implications on farmers’ efficiency and equity. The study was carried out in Mashonaland East Province of Zimbabwe, covering two districts, Goromonzi and Marondera. The focus was specifically on A1 and A2 farmers, as the rental policy was directed at these resettlement models only and much of the informal land rental markets were prevalent among these categories of farmers. Data collection utilised the survey approach. This was supported by key informant interviews and focus group discussions, with a final sample of 339 households selected using multi-stage sampling method. Survey data were transcribed on CsPro 6, and analysed using Stata, SPSS and Frontier 4.1. Results showed that about a third of household respondents was from Marondera and twothirds was from Goromonzi, while 79% and 21% was A1 and A2 farmers respectively. About 80% was male headed households and the remainder was female headed households. About half of the households were not participating in land rental markets while the other half was split almost equally between those renting-in and renting-out land. In general, A2 farmers were better in agricultural productivity than A1 farmers. It was concluded that farmers had a fairly good knowledge of the agricultural land rental policy enunciated in the Finance Bills. A1 farmers were more knowledgeable than A2 farmers, but no vii significant differences were observed between male and female headed households and farmers involved and not involved in land rental markets. Farmers’ attitudes in relation to policy were categorised as fair, with significant differences based on gender and land market participation. Practice scores showed a poor adherence to policy for all categories of farmers. Overall perceptions of farmers on rental policy was inferred as fair with significant differences existing between land rental market participants and non-participants (autarky). The results of a bivariate Tobit model results showed that the decision to rent-in land was significantly influenced by gender, household income, permanent labour, cultivated area, tenure certainty, irrigable land size and crop diversification. On the other hand, age, permanent labour, irrigable land size and crop diversification significantly influenced farmers’ decisions to rent-out land. The conclusion was that household characteristics, land endowments and transaction costs significantly influenced the decision to rent-in land while the former two were strong in influencing renting-out decisions. Results from the linearized Cobb Douglas model showed that economic efficiency for most farmers was above 50%. Farmers renting-out land under A1 were found to be the most economically efficient, followed by those who were renting-in and least efficient were farmers not participating in land rental markets, though the differences were marginal. For the A2 model, renting-in farmers were the most efficient, followed by those in autarky position, while renting-out farmers were the least. Overall, the most efficient farmers were those renting-in, followed by those renting-out while farmers in autarky were the least efficient. Overall efficiency was higher for A2 farmers than for A1 farmers. For farmers not participating in rental markets, the sources of inefficiency were crop type, crop area and labour. For farmers renting-in, it was proportion of irrigable land, size of irrigable land, crop type, crop area and viii labour, while inefficiency drivers for renting-out farmers were crop type and associated area. Equity analysis showed that participation in land rental markets reduced inequality for farmers in the two districts and male and female headed households. Inequality was increased among A1 farmers and remained unchanged among A2 farmers. Overall, the emerging position was that participation in land rental markets resulted in higher efficiency and reduced inequality in land holding among the sampled farmers. It is recommended that government should be consistent on land rental policy and bring into place effective administration of land rental policy. Government may also consider formal acceptance of land rental markets in light of the marginal efficiency and equity benefits shown in the study. However, formalizing land rental markets alone may not be a panacea to improved efficiency and needs to be supported by other productivity measures given the average efficiency values for farmers. Crop and livestock production based on compatibility with the natural regions and defined minimum size of land should be encouraged to improve efficiency
- Full Text:
- Date Issued: 2019
Performing whiteness; representing otherness : Hugh Tracey and African music
- Authors: Coetzee, Paulette June
- Date: 2015
- Subjects: Tracey, Hugh , Music -- Africa , International Library of African Music , Ethnomusicology -- Africa , Ethnomusicologists -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2327 , http://hdl.handle.net/10962/d1016502
- Description: This thesis provides a critical study of texts associated with Hugh Tracey (1903–1977). Tracey is well-known for his work in African music studies, particularly for his major contribution to the recorded archive of musical sound in sub-Saharan Africa and his founding of the International Library of African Music (ILAM) in 1954. My reading of him is informed by a postcolonial perspective, whiteness studies and African scholarship on ways in which constructions of African identity and tradition have been shaped by the colonial archive. In my view, Tracey was part of a mid-twentieth century movement which sought to marshal positive representations of traditional African culture in the interest of maintaining and strengthening colonial rule. While his recording project may have fostered inclusion through creating spaces for indigenous musicians to be heard, it also functioned to promote racist exclusion in the manner of its production, distribution and claims to expertise. Moreover, his initial strategy for ILAM’s sustainability targeted colonial government and industry as primary clients, with the promise that promoting traditional music as a means of entertainment and self-expression for black subjects and workers would ease administration and reduce conflict. I believe that it is important to acknowledge and interrogate the problematic racial attitudes and practices associated with the history of Tracey’s archive – not to undermine its significance in any way but to allow it to be better understood and used more productively in the future.
- Full Text:
- Date Issued: 2015
- Authors: Coetzee, Paulette June
- Date: 2015
- Subjects: Tracey, Hugh , Music -- Africa , International Library of African Music , Ethnomusicology -- Africa , Ethnomusicologists -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2327 , http://hdl.handle.net/10962/d1016502
- Description: This thesis provides a critical study of texts associated with Hugh Tracey (1903–1977). Tracey is well-known for his work in African music studies, particularly for his major contribution to the recorded archive of musical sound in sub-Saharan Africa and his founding of the International Library of African Music (ILAM) in 1954. My reading of him is informed by a postcolonial perspective, whiteness studies and African scholarship on ways in which constructions of African identity and tradition have been shaped by the colonial archive. In my view, Tracey was part of a mid-twentieth century movement which sought to marshal positive representations of traditional African culture in the interest of maintaining and strengthening colonial rule. While his recording project may have fostered inclusion through creating spaces for indigenous musicians to be heard, it also functioned to promote racist exclusion in the manner of its production, distribution and claims to expertise. Moreover, his initial strategy for ILAM’s sustainability targeted colonial government and industry as primary clients, with the promise that promoting traditional music as a means of entertainment and self-expression for black subjects and workers would ease administration and reduce conflict. I believe that it is important to acknowledge and interrogate the problematic racial attitudes and practices associated with the history of Tracey’s archive – not to undermine its significance in any way but to allow it to be better understood and used more productively in the future.
- Full Text:
- Date Issued: 2015
The impact and control of waterweeds in the Southern Mozambique Basin rivers
- Authors: Langa, Sílvia da Fátima
- Date: 2013
- Subjects: Water hyacinth -- Mozambique Water ferns -- Mozambique Water lettuce -- Mozambique Salvinia molesta -- Mozambique Aquatic weeds -- Mozambique Invasive plants -- Mozambique Aquatic weeds -- Control -- Mozambique Invasive plants -- Control -- Mozambique Aquatic weeds -- Biological control -- Mozambique Invasive plants -- Biological control -- Mozambique Aquatic resources -- Management -- Mozambique Beetles -- Mozambique Insects as biological pest control agents -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5587 , http://hdl.handle.net/10962/d1001905
- Description: In Mozambique, establishment of aquatic weeds has been enhanced through the increased enrichment of water bodies by nutrient runoffs from human and agricultural wastes that lead to an increase in nitrate and phosphate in the water. The aquatic weeds, water hyacinth (Eichhornia crassipes), red water fern ( Azolla microphylla), water lettuce (Pistia stratiotes) and salvinia (Salvinia molesta) were found in most watercourses in Mozambique and are becoming aggressive in some watercourses, especially in the Umbeluzi and Incomati rivers. Farmers and people living along the rivers are aware of the negative impact of the water weeds because the large mats of weeds cause loss of shoreline and navigability along the rivers. Other commonly perceived effects of aquatic invasive plants in Mozambique rivers include: reduced navigable surface area; difficulties for fishermen, which reduces income; increased prevalence of insects and insect-borne disease, and decreased aesthetic value. The methods currently used for the control and management of the aquatic weeds are mechanical and manual control. Both methods are costly, time consuming, and only provide a short-term solution to the problem. The study found that the weevils Neochetina eichhorniae and N. bruchi were effective biological control agents in the study area but their impact is too gradual compared to the aggressive proliferation of water hyacinth. The one year lab-experiment clearly demonstrated that the water lettuce weed had a significant impact on the recruitment of macro-invertebrates to the artificial substrates, and water lettuce contributed to the reduction of oxygen in the water and consequent reduction of macro-invertebrate abundance and diversity. The biodiversity recovered at the same time in the pools containing water lettuce controlled by N. affinis and water lettuce controlled by herbicide, but richness and diversity of macro-invertebrates was higher in the water lettuce controlled by N affinis during the first sampling occasion compared to the water lettuce in pools controlled by herbicide, where macro-invertebrates increased only when DO levels recovered after water lettuce mat decay. The number of taxa recorded in this study is an indication of the significance of macro-invertebrates in an aquatic environment. This therefore emphasizes the need for more research efforts into macrophyte and macro-invertebrate associations in the aquatic system to better understand the implications of habitat modification arising from human activities. It will also enable us to be better equipped with a more appropriate ecological understanding for aquatic resources management.
- Full Text:
- Date Issued: 2013
- Authors: Langa, Sílvia da Fátima
- Date: 2013
- Subjects: Water hyacinth -- Mozambique Water ferns -- Mozambique Water lettuce -- Mozambique Salvinia molesta -- Mozambique Aquatic weeds -- Mozambique Invasive plants -- Mozambique Aquatic weeds -- Control -- Mozambique Invasive plants -- Control -- Mozambique Aquatic weeds -- Biological control -- Mozambique Invasive plants -- Biological control -- Mozambique Aquatic resources -- Management -- Mozambique Beetles -- Mozambique Insects as biological pest control agents -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5587 , http://hdl.handle.net/10962/d1001905
- Description: In Mozambique, establishment of aquatic weeds has been enhanced through the increased enrichment of water bodies by nutrient runoffs from human and agricultural wastes that lead to an increase in nitrate and phosphate in the water. The aquatic weeds, water hyacinth (Eichhornia crassipes), red water fern ( Azolla microphylla), water lettuce (Pistia stratiotes) and salvinia (Salvinia molesta) were found in most watercourses in Mozambique and are becoming aggressive in some watercourses, especially in the Umbeluzi and Incomati rivers. Farmers and people living along the rivers are aware of the negative impact of the water weeds because the large mats of weeds cause loss of shoreline and navigability along the rivers. Other commonly perceived effects of aquatic invasive plants in Mozambique rivers include: reduced navigable surface area; difficulties for fishermen, which reduces income; increased prevalence of insects and insect-borne disease, and decreased aesthetic value. The methods currently used for the control and management of the aquatic weeds are mechanical and manual control. Both methods are costly, time consuming, and only provide a short-term solution to the problem. The study found that the weevils Neochetina eichhorniae and N. bruchi were effective biological control agents in the study area but their impact is too gradual compared to the aggressive proliferation of water hyacinth. The one year lab-experiment clearly demonstrated that the water lettuce weed had a significant impact on the recruitment of macro-invertebrates to the artificial substrates, and water lettuce contributed to the reduction of oxygen in the water and consequent reduction of macro-invertebrate abundance and diversity. The biodiversity recovered at the same time in the pools containing water lettuce controlled by N. affinis and water lettuce controlled by herbicide, but richness and diversity of macro-invertebrates was higher in the water lettuce controlled by N affinis during the first sampling occasion compared to the water lettuce in pools controlled by herbicide, where macro-invertebrates increased only when DO levels recovered after water lettuce mat decay. The number of taxa recorded in this study is an indication of the significance of macro-invertebrates in an aquatic environment. This therefore emphasizes the need for more research efforts into macrophyte and macro-invertebrate associations in the aquatic system to better understand the implications of habitat modification arising from human activities. It will also enable us to be better equipped with a more appropriate ecological understanding for aquatic resources management.
- Full Text:
- Date Issued: 2013
Games as communication: an analysis of advertising in South Africa
- Authors: Wright, Bianca Maria-Teresa
- Date: 2012
- Subjects: Internet advertising , Branding (Marketing)
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8417 , http://hdl.handle.net/10948/d1012929
- Description: Games as a form of communication have been examined by academics in the fields of game studies, narratology and media studies, among others, but the use of games to communicate advertising messages has not been adequately explored within the South African context. The study sought to investigate the phenomenon of advergaming, purpose-built games designed to communicate an advertising message, in South Africa, and to develop a model for the use of advergaming as a viral marketing tool in this context. Using a hybrid approach, the study examined the way that advertising agencies currently use advergames as well as the effectiveness of advergaming as a means to communicate a message. The study presents the results of a national survey of advertising agencies in South Africa, a content analysis of existing advergames and an analysis of three semi-structured group interview experiments conducted using selected advergames. The findings point to the potential of advergaming as a message communication tool, but also highlight the challenges that may hamper the widespread use of advergaming in South Africa. It proposes the use of the mobile environment as a means to reach a wider South African audience and in that way, overcome some of the obstacles to advergaming adoption. In addition, the results identify aspects of advergames that seem to correlate with the effectiveness of message communication.
- Full Text:
- Date Issued: 2012
- Authors: Wright, Bianca Maria-Teresa
- Date: 2012
- Subjects: Internet advertising , Branding (Marketing)
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8417 , http://hdl.handle.net/10948/d1012929
- Description: Games as a form of communication have been examined by academics in the fields of game studies, narratology and media studies, among others, but the use of games to communicate advertising messages has not been adequately explored within the South African context. The study sought to investigate the phenomenon of advergaming, purpose-built games designed to communicate an advertising message, in South Africa, and to develop a model for the use of advergaming as a viral marketing tool in this context. Using a hybrid approach, the study examined the way that advertising agencies currently use advergames as well as the effectiveness of advergaming as a means to communicate a message. The study presents the results of a national survey of advertising agencies in South Africa, a content analysis of existing advergames and an analysis of three semi-structured group interview experiments conducted using selected advergames. The findings point to the potential of advergaming as a message communication tool, but also highlight the challenges that may hamper the widespread use of advergaming in South Africa. It proposes the use of the mobile environment as a means to reach a wider South African audience and in that way, overcome some of the obstacles to advergaming adoption. In addition, the results identify aspects of advergames that seem to correlate with the effectiveness of message communication.
- Full Text:
- Date Issued: 2012
The role of the euthecosome pteropod, limacina retroversa, in the polar frontal zone, Southern Ocean
- Authors: Bernard, Kim Sarah
- Date: 2007
- Subjects: Pteropoda Limacidae Zooplankton -- Antarctic Ocean Copepoda Phytoplankton
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5761 , http://hdl.handle.net/10962/d1005449
- Description: The aim of the present study was to assess the ecological role of the euthecosome pteropod, Limacina retroversa, in particular, and the mesozooplankton community, in general, in the pelagic ecosystem of the Polar Frontal Zone (PFZ), Southern Ocean. Data were collected from four oceanographic surveys to the Indian sector of the PFZ during austral autumn 2000, 2002, 2004 and 2005. Copepods, mainly Calanus simillimus, Oithona similis, Clausocalanus spp. and Ctenocalanus spp., typically dominated total mesozooplankton counts, accounting for, on average, between 75.5 % and 88.1 % (Mean = 77.4 %; SD = 13.4 %) of the total, during the present investigation. Results of the study indicate that L. retroversa may, at times, contribute substantially to total mesozooplankton abundances. During the study, L. retroversa contributed between 0.0 and 30.0 % (Mean = 5.3 %; SD = 7.1 %) to total mesozooplankton numbers. Significant small-scale variability in abundance and size structure of L. retroversa and abundance of copepods was minimal. Inter-annual variability, on the other hand, was significant between some years. Total pteropod numbers were greatest during April 2002 and 2004, while copepods exhibited greatest abundances during April 2004 only. Pearson’s Correlation analysis suggested that L. retroversa abundances were positively correlated to total surface chlorophyll-a (chl-a) concentrations. The significantly lower chl-a concentrations recorded during April 2005 may explain the reduced pteropod numbers observed during that survey. The size class structure of L. retroversa comprised mainly small and mediumsized individuals during all four surveys. This corresponds well with records from the northern hemisphere (sub-Arctic and Arctic waters) where Limacina spp. are reported to exhibit maximum spawning during mid to late-summer. Higher abundances of large individuals only occurred during April 2005, when chl-a concentrations were very low; possibly the result of delayed spawning, due to reduced food availability. Ingestion rates of the four most abundant copepods, determined using the gut fluorescence technique, ranged between 159.32 ng (pigm) ind⁻¹ day⁻¹ and 728.36 ng (pigm) ind⁻¹ day⁻¹ (Mean = 321.01 ng (pigm) ind⁻¹ day⁻¹; SD = 173.91 ng (pigm) ind⁻¹ day). Ingestion rates of L. retroversa were much higher, ranging from an average of 4 28.68 ng (pigm) ind⁻¹ day⁻¹ in April 2002 to 4 196.88 ng (pigm) ind⁻¹day⁻¹in April 2005 (Mean = 4157.36 ng (pigm) ind⁻¹ day⁻¹; SD = 35.37 ng (pigm) ind⁻¹day⁻¹). Average daily grazing rates for the pteropod varied between 0.39 mg (pigm) m⁻² day⁻¹ in April 2005 and 17.69 mg (pigm) m-2 day-1 in April 2004 (Mean = 6.13 mg (pigm) m⁻² day⁻¹; SD = 11.04 mg (pigm) m⁻² day⁻¹); corresponding average daily grazing impacts ranged between 8.4 % and 139.8 % of the phytoplankton standing stock in April 2005 and 2004, respectively (Mean = 48.5 %; SD = 84.5 %). Average daily grazing rates of the four copepods ranged from 4.58 mg (pigm) m⁻² day⁻¹ to 8.77 mg (pigm) m⁻² day⁻¹ -1, during April 2002 and 2004, respectively (Mean = 6.28 mg (pigm) m⁻² day⁻¹; SD = 5.94 mg (pigm) m⁻² day⁻¹). Collectively, the copepods removed an average of between 31.6 % and 89.8 % of the phytoplankton standing stock per day, during April 2002 and 2004, respectively (Mean = 70.8 %; SD = 86.7 %). The daily grazing impact of the copepods accounted for an average of between 40.4 % and 87.8 % of the total zooplankton grazing impact, during April 2004 and 2005, respectively (Mean = 75.0 %; SD = 65.5 %). L. retroversa was responsible for an average of 52.4 % and 59.5 % of the total zooplankton grazing impact, during April 2002 and 2004, respectively. However, during April 2005, when L. retroversa numbers were significantly lower than previous years, the pteropod contributed an average of only 7.5 % to the total zooplankton grazing impact. Thus, during the present investigation,the pteropod was responsible for removing a mean of 48.9 % of the available phytoplankton (SD = 74.9 %). The predation impact of the dominant carnivorous macrozooplankton and micronekton in the PFZ was determined during April 2004 and 2005 using daily ration estimates obtained from the literature. Additionally, gut content analysis was used to determine the contribution of L. retroversa to the diet of the dominant predators. Average predation impact ranged from 1.1 % and 5.7 % of the total mesozooplankton standing stock during April 2004 and 2005, respectively (Mean = 3.8 %; SD = 12.3 %). Chaetognaths and euphausiids dominated total carnivore numbers and made the greatest contributions to total predation impact during both years. Copepods appeared to be the main prey item of the dominant carnivorous macrozooplankton-micronekton in the region. L. retroversa was only detected in the gut contents of the amphipod, Themisto gaudichaudi, but not in either of the chaetognath species (Eukrohnia hamata and Sagitta gazellae) or the myctophid fish (Electrona spp.). The pteropod was found in 19 % of amphipod guts dissected. Pearson’s Correlation analyses showed that the four major predatory zooplankton groups found in the PFZ (chaetognaths, euphausiids, amphipods and myctophid fish) were positively correlated to abundances of L. retroversa, suggesting that the pteropod might be an important prey item for many of the carnivorous macrozooplankton/micronekton in the PFZ. To conclude, L. retroversa may play an important role in the pelagic ecosystem of the PFZ, in austral autumn. However, ocean acidification and calcium carbonate undersaturation (as a result of increased anthropogenic carbon dioxide emissions), that is predicted to occur within the next 50 – 100 years, will most likely have significant implications for the Sub-Antarctic pelagic ecosystem if L. retroversa cannot adapt quickly enough to the changes.
- Full Text:
- Date Issued: 2007
The role of the euthecosome pteropod, limacina retroversa, in the polar frontal zone, Southern Ocean
- Authors: Bernard, Kim Sarah
- Date: 2007
- Subjects: Pteropoda Limacidae Zooplankton -- Antarctic Ocean Copepoda Phytoplankton
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5761 , http://hdl.handle.net/10962/d1005449
- Description: The aim of the present study was to assess the ecological role of the euthecosome pteropod, Limacina retroversa, in particular, and the mesozooplankton community, in general, in the pelagic ecosystem of the Polar Frontal Zone (PFZ), Southern Ocean. Data were collected from four oceanographic surveys to the Indian sector of the PFZ during austral autumn 2000, 2002, 2004 and 2005. Copepods, mainly Calanus simillimus, Oithona similis, Clausocalanus spp. and Ctenocalanus spp., typically dominated total mesozooplankton counts, accounting for, on average, between 75.5 % and 88.1 % (Mean = 77.4 %; SD = 13.4 %) of the total, during the present investigation. Results of the study indicate that L. retroversa may, at times, contribute substantially to total mesozooplankton abundances. During the study, L. retroversa contributed between 0.0 and 30.0 % (Mean = 5.3 %; SD = 7.1 %) to total mesozooplankton numbers. Significant small-scale variability in abundance and size structure of L. retroversa and abundance of copepods was minimal. Inter-annual variability, on the other hand, was significant between some years. Total pteropod numbers were greatest during April 2002 and 2004, while copepods exhibited greatest abundances during April 2004 only. Pearson’s Correlation analysis suggested that L. retroversa abundances were positively correlated to total surface chlorophyll-a (chl-a) concentrations. The significantly lower chl-a concentrations recorded during April 2005 may explain the reduced pteropod numbers observed during that survey. The size class structure of L. retroversa comprised mainly small and mediumsized individuals during all four surveys. This corresponds well with records from the northern hemisphere (sub-Arctic and Arctic waters) where Limacina spp. are reported to exhibit maximum spawning during mid to late-summer. Higher abundances of large individuals only occurred during April 2005, when chl-a concentrations were very low; possibly the result of delayed spawning, due to reduced food availability. Ingestion rates of the four most abundant copepods, determined using the gut fluorescence technique, ranged between 159.32 ng (pigm) ind⁻¹ day⁻¹ and 728.36 ng (pigm) ind⁻¹ day⁻¹ (Mean = 321.01 ng (pigm) ind⁻¹ day⁻¹; SD = 173.91 ng (pigm) ind⁻¹ day). Ingestion rates of L. retroversa were much higher, ranging from an average of 4 28.68 ng (pigm) ind⁻¹ day⁻¹ in April 2002 to 4 196.88 ng (pigm) ind⁻¹day⁻¹in April 2005 (Mean = 4157.36 ng (pigm) ind⁻¹ day⁻¹; SD = 35.37 ng (pigm) ind⁻¹day⁻¹). Average daily grazing rates for the pteropod varied between 0.39 mg (pigm) m⁻² day⁻¹ in April 2005 and 17.69 mg (pigm) m-2 day-1 in April 2004 (Mean = 6.13 mg (pigm) m⁻² day⁻¹; SD = 11.04 mg (pigm) m⁻² day⁻¹); corresponding average daily grazing impacts ranged between 8.4 % and 139.8 % of the phytoplankton standing stock in April 2005 and 2004, respectively (Mean = 48.5 %; SD = 84.5 %). Average daily grazing rates of the four copepods ranged from 4.58 mg (pigm) m⁻² day⁻¹ to 8.77 mg (pigm) m⁻² day⁻¹ -1, during April 2002 and 2004, respectively (Mean = 6.28 mg (pigm) m⁻² day⁻¹; SD = 5.94 mg (pigm) m⁻² day⁻¹). Collectively, the copepods removed an average of between 31.6 % and 89.8 % of the phytoplankton standing stock per day, during April 2002 and 2004, respectively (Mean = 70.8 %; SD = 86.7 %). The daily grazing impact of the copepods accounted for an average of between 40.4 % and 87.8 % of the total zooplankton grazing impact, during April 2004 and 2005, respectively (Mean = 75.0 %; SD = 65.5 %). L. retroversa was responsible for an average of 52.4 % and 59.5 % of the total zooplankton grazing impact, during April 2002 and 2004, respectively. However, during April 2005, when L. retroversa numbers were significantly lower than previous years, the pteropod contributed an average of only 7.5 % to the total zooplankton grazing impact. Thus, during the present investigation,the pteropod was responsible for removing a mean of 48.9 % of the available phytoplankton (SD = 74.9 %). The predation impact of the dominant carnivorous macrozooplankton and micronekton in the PFZ was determined during April 2004 and 2005 using daily ration estimates obtained from the literature. Additionally, gut content analysis was used to determine the contribution of L. retroversa to the diet of the dominant predators. Average predation impact ranged from 1.1 % and 5.7 % of the total mesozooplankton standing stock during April 2004 and 2005, respectively (Mean = 3.8 %; SD = 12.3 %). Chaetognaths and euphausiids dominated total carnivore numbers and made the greatest contributions to total predation impact during both years. Copepods appeared to be the main prey item of the dominant carnivorous macrozooplankton-micronekton in the region. L. retroversa was only detected in the gut contents of the amphipod, Themisto gaudichaudi, but not in either of the chaetognath species (Eukrohnia hamata and Sagitta gazellae) or the myctophid fish (Electrona spp.). The pteropod was found in 19 % of amphipod guts dissected. Pearson’s Correlation analyses showed that the four major predatory zooplankton groups found in the PFZ (chaetognaths, euphausiids, amphipods and myctophid fish) were positively correlated to abundances of L. retroversa, suggesting that the pteropod might be an important prey item for many of the carnivorous macrozooplankton/micronekton in the PFZ. To conclude, L. retroversa may play an important role in the pelagic ecosystem of the PFZ, in austral autumn. However, ocean acidification and calcium carbonate undersaturation (as a result of increased anthropogenic carbon dioxide emissions), that is predicted to occur within the next 50 – 100 years, will most likely have significant implications for the Sub-Antarctic pelagic ecosystem if L. retroversa cannot adapt quickly enough to the changes.
- Full Text:
- Date Issued: 2007
The new economic geography of SADC free trade area
- Authors: Hess, Simon Peter
- Date: 2004
- Subjects: Southern African Development Community Free trade -- Africa, Southern Economic geography Industries -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:932 , http://hdl.handle.net/10962/d1001648
- Description: The current implementation of a free trade area in SADC has given rise to concerns that the present location of industry in the region will be adversely affected. Specifically, many of the smaller and less-developed countries fear that this change will result in a loss of their industry towards the more developed members, and particularly towards South Africa. This study uses the framework of the new economic geography to address these concerns. The new economic geography is a body of theory that has arisen in the last decade and allows for a dynamic analysis of the process of regional integration. Studies of such dynamic effects in the developing country context are exceedingly scarce, and particularly so in southern Africa. Another area of little research is in the comparison of the evolving industrial structure of different regional blocs. Thus, in response to this gap in the literature and in order to address the concerns of polarisation of industry within the SADC region, a two-pronged empirical approach is taken. The study first conducts a review of the spatial distribution of industry within SADC from 1970 to 1999. This is achieved through the calculation and examination of industrial locational Gini coefficients, measuring the relative degree of concentration of 28 ISIC (rev 2) industries for the years 1970, 1980, 1985, 1990, 1995 and 1999. Secondly, an empirical comparison is conducted with other blocs that are in the process of deepening regional integration, namely the European Union and Mercosur. Again, this is done through the calculation of locational Gini coefficients for individual industries for all three blocs at five year intervals from 1980 to 1995, and then for 1999. The average level of concentration within SADC is found to increase steadily from 1970 to 1990. Between 1990 and 1995, the level of concentration increases further, but at a lower rate, and, by 1999 industry begins to disperse. The Gini coefficient is a relative measure, and thus does not measure the absolute level of concentration. Thus, much of the increase in concentration seen is towards peripheral countries. To further interpret the Gini, the changes in concentration are compared to the absolute changes in manufacturing employment in South Africa. From this analysis, eight of the 28 industries analysed show particular tendencies to concentrate in the periphery. These are beverages, textiles, wearing apparel, paper and products, rubber products, other non-metallic mineral products, transport equipment, and professional and scientific equipment. Likewise, another six industries become more concentrated in South Africa over this time, namely food products, printing and publishing, industrial chemicals, petroleum refineries, miscellaneous petroleum and coal products, and electrical machinery. According to the Gini coefficient, the tobacco industry is by far the most concentrated, while the wood products industry is the most dispersed. It is also found that scale-intensive industries tend to be among the most concentrated. In the cross-bloc comparison, Mercosur has the lowest level of aggregate concentration with an average Gini of 0.08 in 1999. This compares with Ginis of 0.28 for the EU, and 0.22 for SADC. The EU has the largest increase in concentration over the period, while the concentration in Mercosur falls during the 1980s, increases in the mid 1990s and then falls again by 1999. A common theme, however, between all three blocs is a trend towards dispersion in the late 1990s. This is particularly apparent in SADC and Mercosur where the Gini decreases in value, while in the EU, the Gini only increases marginally in this period. Other studies of the EU have indicated that industry was starting to disperse at this time. This finding would be more apparent at a greater level of industrial disaggregation. The following industries are found to be agglomerated above the average level in all three blocs: tobacco, miscellaneous petroleum and coal products, and pottery china and earthenware. Conversely, transport equipment, paper and products, machinery except electrical, plastic products, rubber products, and fabricated metal products tend to be more dispersed across all three. Perhaps more interesting is that there appears to be some commonality between industries that become more agglomerated across all three blocs, while industries that dispersed tend to be region specific. The industries that show universal agglomeration tendencies are the highly sensitive wearing apparel and textiles industries, in addition to industrial chemicals, printing and publishing, iron and steel, and plastic products. In relation to SADC, the first two of these industries show an increased concentration in the periphery, as in the EU, while the remaining industries show tendencies to concentrate in the core. The new economic geography predicts that, as the presently high levels of transport costs begin to fall in SADC, industry will tend to concentrate in the core. However, the results of this study indicate that the effect on manufacturing is, to a large extent, sector specific, with some manufacturing industries concentrating in the core and others in the periphery. The study therefore concludes that the mass polarization of industry from the smaller countries in SADC towards South Africa is unlikely to occur with the further reduction in trade costs. Although certain industries may be attracted towards the core, the high degree of wage disparity in the region and present trade concessions from developed markets overseas towards the peripheral countries, will make these countries an attractive location, particularly for export orientated firms. Two main policy recommendations result from the study. Firstly, individual countries in SADC need to promote those industries that show concentration tendencies in their country. Secondly, in order for the periphery to maximize their gain from the free trade area, transport costs within the region need to be reduced rapidly and effectively.
- Full Text:
- Date Issued: 2004
- Authors: Hess, Simon Peter
- Date: 2004
- Subjects: Southern African Development Community Free trade -- Africa, Southern Economic geography Industries -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:932 , http://hdl.handle.net/10962/d1001648
- Description: The current implementation of a free trade area in SADC has given rise to concerns that the present location of industry in the region will be adversely affected. Specifically, many of the smaller and less-developed countries fear that this change will result in a loss of their industry towards the more developed members, and particularly towards South Africa. This study uses the framework of the new economic geography to address these concerns. The new economic geography is a body of theory that has arisen in the last decade and allows for a dynamic analysis of the process of regional integration. Studies of such dynamic effects in the developing country context are exceedingly scarce, and particularly so in southern Africa. Another area of little research is in the comparison of the evolving industrial structure of different regional blocs. Thus, in response to this gap in the literature and in order to address the concerns of polarisation of industry within the SADC region, a two-pronged empirical approach is taken. The study first conducts a review of the spatial distribution of industry within SADC from 1970 to 1999. This is achieved through the calculation and examination of industrial locational Gini coefficients, measuring the relative degree of concentration of 28 ISIC (rev 2) industries for the years 1970, 1980, 1985, 1990, 1995 and 1999. Secondly, an empirical comparison is conducted with other blocs that are in the process of deepening regional integration, namely the European Union and Mercosur. Again, this is done through the calculation of locational Gini coefficients for individual industries for all three blocs at five year intervals from 1980 to 1995, and then for 1999. The average level of concentration within SADC is found to increase steadily from 1970 to 1990. Between 1990 and 1995, the level of concentration increases further, but at a lower rate, and, by 1999 industry begins to disperse. The Gini coefficient is a relative measure, and thus does not measure the absolute level of concentration. Thus, much of the increase in concentration seen is towards peripheral countries. To further interpret the Gini, the changes in concentration are compared to the absolute changes in manufacturing employment in South Africa. From this analysis, eight of the 28 industries analysed show particular tendencies to concentrate in the periphery. These are beverages, textiles, wearing apparel, paper and products, rubber products, other non-metallic mineral products, transport equipment, and professional and scientific equipment. Likewise, another six industries become more concentrated in South Africa over this time, namely food products, printing and publishing, industrial chemicals, petroleum refineries, miscellaneous petroleum and coal products, and electrical machinery. According to the Gini coefficient, the tobacco industry is by far the most concentrated, while the wood products industry is the most dispersed. It is also found that scale-intensive industries tend to be among the most concentrated. In the cross-bloc comparison, Mercosur has the lowest level of aggregate concentration with an average Gini of 0.08 in 1999. This compares with Ginis of 0.28 for the EU, and 0.22 for SADC. The EU has the largest increase in concentration over the period, while the concentration in Mercosur falls during the 1980s, increases in the mid 1990s and then falls again by 1999. A common theme, however, between all three blocs is a trend towards dispersion in the late 1990s. This is particularly apparent in SADC and Mercosur where the Gini decreases in value, while in the EU, the Gini only increases marginally in this period. Other studies of the EU have indicated that industry was starting to disperse at this time. This finding would be more apparent at a greater level of industrial disaggregation. The following industries are found to be agglomerated above the average level in all three blocs: tobacco, miscellaneous petroleum and coal products, and pottery china and earthenware. Conversely, transport equipment, paper and products, machinery except electrical, plastic products, rubber products, and fabricated metal products tend to be more dispersed across all three. Perhaps more interesting is that there appears to be some commonality between industries that become more agglomerated across all three blocs, while industries that dispersed tend to be region specific. The industries that show universal agglomeration tendencies are the highly sensitive wearing apparel and textiles industries, in addition to industrial chemicals, printing and publishing, iron and steel, and plastic products. In relation to SADC, the first two of these industries show an increased concentration in the periphery, as in the EU, while the remaining industries show tendencies to concentrate in the core. The new economic geography predicts that, as the presently high levels of transport costs begin to fall in SADC, industry will tend to concentrate in the core. However, the results of this study indicate that the effect on manufacturing is, to a large extent, sector specific, with some manufacturing industries concentrating in the core and others in the periphery. The study therefore concludes that the mass polarization of industry from the smaller countries in SADC towards South Africa is unlikely to occur with the further reduction in trade costs. Although certain industries may be attracted towards the core, the high degree of wage disparity in the region and present trade concessions from developed markets overseas towards the peripheral countries, will make these countries an attractive location, particularly for export orientated firms. Two main policy recommendations result from the study. Firstly, individual countries in SADC need to promote those industries that show concentration tendencies in their country. Secondly, in order for the periphery to maximize their gain from the free trade area, transport costs within the region need to be reduced rapidly and effectively.
- Full Text:
- Date Issued: 2004
Cell-free biosynthesis of abscisic acid (ABA) in extracts of flavedo from Citrus sinensis (L.) osbeck
- Richardson, Gaynor Rose-Marie
- Authors: Richardson, Gaynor Rose-Marie
- Date: 1996
- Subjects: Biosynthesis Abscisic acid Citrus fruits
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4221 , http://hdl.handle.net/10962/d1003790
- Description: The biosynthetic origin of the plant growth regulator abscisic acid remains equivocal and almost nothing is known about the enzymes involved in this process. The present research programme describes the development of a cell-free system, capable of synthesizing abscisic acid and attempts to provide further information about the biochemistry and enzymology of this important biosynthetic pathway. Cell-free extracts were prepared either directly from the flavedo (crude) or from an acetone powder derived from flavedo, of mature coloured fruits of Citrus sinensis L. cv. Midknight and incubated with mevalonic acid, isopentenyl pyrophosphate, famesylpyrophosphate, geranylgeranyl pyrophosphate, ß-carotene and 1',4'-trans-abscisic acid diol. The neutral and acidic products formed were purified by thin-layer chromatography and high performance liquid chromatography, and quantified by high performance liquid chromatography, gas chromatography-electron capture and unequivocally identified by combined gas chromatography-mass spectrometry. Abscisic acid, 1',4'-trans-abscisic acid diol and phaseic acid were unequivocally identified as the major acidic products formed in this cell-free system. The acid fraction also contained xanthoxin acid. Labelled and unlabelled ß-carotene was converted into the neutral compounds xanthoxin and xanthoxin alcohol. In addition. high performance liquid chromatography-photodiode array analYSis of the oxy-carotenoid fraction revealed the complete spectrum of ß, ß-carotenoids induding zeaxanthin, antheraxanthin and violaxanthin with accumulation of an oxygenated carotenoid tentatively identified as 9- cis-violaxanthin. Identification of putative C₁₅ intermediates was achieved by either UV spectrophotometry and combined capillary gas chromatography-mass spectrometry or microchemical analYSis and co-chromatography. Refeeding studies using (±)-[2-¹⁴C]_ abscisic acid diol as substrate revealed that abscisic acid was not metabolized to abscisic acid diol, suggesting that it was/is produced as an intermediate rather than as a catabolite of ABA in this system. Stigmasterol, and to a lesser extent cholesterol reduced conversion of ß-carotene to abscisic acid but did not influence transformation of 1',4'-trans-abscisic acid diol to abscisic acid. AM01618 stimulated fonnation of abscisic acid and appeared to exert its effect at the level of conversion of 1' ,4'-trans-abscisic acid diol. Zeatin and the cytokinin analogue, ancymidol inhibited the biosynthesis of abscisic acid whereas dithiothreitol increased incorporation of label from ß-carotene into abscisic acid suggesting involvement of a cytochrome P450-type mixed function oxidase in this reaction sequence. Sodium dodecylsulphate polyacrylamide gel electrophoresis of the enzyme extract derived from Citrus flavedo revealed the presence of a 53 kD protein with peroxidase activity characteristic of a cytochrome P-450. Abscisic acid biosynthesizing activity was always greater in extracts from acetone powder and abscisic acid biosynthesis was enhanced in the presence of AMO 1618, NAD+, NADH, NADPH, MgCI₂ and Molybdate but was inhibited by FAD. Activity was further enhanced by the addition of (R,S)-abscisic acid as a cold-pool trap and by induding 0.1% w/v of either Tween 20 or Triton X 100 in the extraction buffer. When cis-ß-carotene was used as substrate, no abscisic acid was produced. Conversely when either all-trans-ß-carotene or a mixture of the two isomers was used, incorporation into abscisic acid occurred. Upoxygenase activity in cell-free extracts of Citrus flavedo increased with increasing protein concentration. As the ability of lipoxygenase to make xanthoxin from violaxanthin, had been reported, increased activity in the cell-free system implied that carotenoid deavage was being brought about by a non-haem oxygenase with lipoxygenase-like properties. Reports had implicated phoshorylation in the activation of many catalytic enzymes (Hanks et aI., 1985). Phosphorylation of the enzymes in this cell-free system proved unsuccessful. Further, it had been reported that in vitro phosphorylation of several membrane polypeptides and soluble polypeptides from com, had been promoted by the addition of Ca²₊ In this cell-free system Ca + did not have a stimulatory effect on protein phosphorylation. Dioxygenases generally occur as soluble enzymes, where they catalyse many oxygenation reactions in metabolic pathways. The addition of 2-oxo-glutarate, a requirement of most soluble oxidases, did not affect the activity of the cell-free system.
- Full Text:
- Date Issued: 1996
- Authors: Richardson, Gaynor Rose-Marie
- Date: 1996
- Subjects: Biosynthesis Abscisic acid Citrus fruits
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4221 , http://hdl.handle.net/10962/d1003790
- Description: The biosynthetic origin of the plant growth regulator abscisic acid remains equivocal and almost nothing is known about the enzymes involved in this process. The present research programme describes the development of a cell-free system, capable of synthesizing abscisic acid and attempts to provide further information about the biochemistry and enzymology of this important biosynthetic pathway. Cell-free extracts were prepared either directly from the flavedo (crude) or from an acetone powder derived from flavedo, of mature coloured fruits of Citrus sinensis L. cv. Midknight and incubated with mevalonic acid, isopentenyl pyrophosphate, famesylpyrophosphate, geranylgeranyl pyrophosphate, ß-carotene and 1',4'-trans-abscisic acid diol. The neutral and acidic products formed were purified by thin-layer chromatography and high performance liquid chromatography, and quantified by high performance liquid chromatography, gas chromatography-electron capture and unequivocally identified by combined gas chromatography-mass spectrometry. Abscisic acid, 1',4'-trans-abscisic acid diol and phaseic acid were unequivocally identified as the major acidic products formed in this cell-free system. The acid fraction also contained xanthoxin acid. Labelled and unlabelled ß-carotene was converted into the neutral compounds xanthoxin and xanthoxin alcohol. In addition. high performance liquid chromatography-photodiode array analYSis of the oxy-carotenoid fraction revealed the complete spectrum of ß, ß-carotenoids induding zeaxanthin, antheraxanthin and violaxanthin with accumulation of an oxygenated carotenoid tentatively identified as 9- cis-violaxanthin. Identification of putative C₁₅ intermediates was achieved by either UV spectrophotometry and combined capillary gas chromatography-mass spectrometry or microchemical analYSis and co-chromatography. Refeeding studies using (±)-[2-¹⁴C]_ abscisic acid diol as substrate revealed that abscisic acid was not metabolized to abscisic acid diol, suggesting that it was/is produced as an intermediate rather than as a catabolite of ABA in this system. Stigmasterol, and to a lesser extent cholesterol reduced conversion of ß-carotene to abscisic acid but did not influence transformation of 1',4'-trans-abscisic acid diol to abscisic acid. AM01618 stimulated fonnation of abscisic acid and appeared to exert its effect at the level of conversion of 1' ,4'-trans-abscisic acid diol. Zeatin and the cytokinin analogue, ancymidol inhibited the biosynthesis of abscisic acid whereas dithiothreitol increased incorporation of label from ß-carotene into abscisic acid suggesting involvement of a cytochrome P450-type mixed function oxidase in this reaction sequence. Sodium dodecylsulphate polyacrylamide gel electrophoresis of the enzyme extract derived from Citrus flavedo revealed the presence of a 53 kD protein with peroxidase activity characteristic of a cytochrome P-450. Abscisic acid biosynthesizing activity was always greater in extracts from acetone powder and abscisic acid biosynthesis was enhanced in the presence of AMO 1618, NAD+, NADH, NADPH, MgCI₂ and Molybdate but was inhibited by FAD. Activity was further enhanced by the addition of (R,S)-abscisic acid as a cold-pool trap and by induding 0.1% w/v of either Tween 20 or Triton X 100 in the extraction buffer. When cis-ß-carotene was used as substrate, no abscisic acid was produced. Conversely when either all-trans-ß-carotene or a mixture of the two isomers was used, incorporation into abscisic acid occurred. Upoxygenase activity in cell-free extracts of Citrus flavedo increased with increasing protein concentration. As the ability of lipoxygenase to make xanthoxin from violaxanthin, had been reported, increased activity in the cell-free system implied that carotenoid deavage was being brought about by a non-haem oxygenase with lipoxygenase-like properties. Reports had implicated phoshorylation in the activation of many catalytic enzymes (Hanks et aI., 1985). Phosphorylation of the enzymes in this cell-free system proved unsuccessful. Further, it had been reported that in vitro phosphorylation of several membrane polypeptides and soluble polypeptides from com, had been promoted by the addition of Ca²₊ In this cell-free system Ca + did not have a stimulatory effect on protein phosphorylation. Dioxygenases generally occur as soluble enzymes, where they catalyse many oxygenation reactions in metabolic pathways. The addition of 2-oxo-glutarate, a requirement of most soluble oxidases, did not affect the activity of the cell-free system.
- Full Text:
- Date Issued: 1996
Prosocial behaviour in South African students a qualitative enquiry
- Authors: Cholerton, Steven M
- Date: 1995
- Subjects: Helping behavior , Interpersonal relations , Altruism , Social ethics , College students -- South Africa -- Attitudes
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:2948 , http://hdl.handle.net/10962/d1002457 , Helping behavior , Interpersonal relations , Altruism , Social ethics , College students -- South Africa -- Attitudes
- Description: The central aim of this study was to conduct a qualitative exploration of the prosocial inclinations possessed by young South African students. The literature review argues that traditional approaches to moral responding separate the individual from the social. An alternative approach that reinstates language and ideology is delineated. It is argued that such a paradigm is most appropriate to a study of prosocial responding during a period of social change. Hypothetical moral dilemmas were administered to twenty-nine students. Six students were selected and each was interviewed on two separate occasions. In this way six case studies were developed. The methodological traditions of phenomenology and hermeneutics were employed to analyze the protocols and subsequent interviews. Seven themes descriptive of a moral response were identified. These consisted of moral reasoning, empathy, mood, guilt, alienation, a sense of group-identity, and ambiguity regarding the relative interests of self versus other. These themes are fully discussed in terms of the literature. It is concluded that moral reasoning may be insufficient to motivate prosocial behaviour. Conventional moral narratives may be appropriated in order to make sense of conflicting emotions. Empathy was identified as a necessary but not sufficient condition for a prosocial response. Empathy might translate into either sympathy or personal distress. Mood was found to largely dictate attentional focus. Alienation was found to be a defensive formulation that inhibits the emergence of sympathy. Guilt might precipitate an alienated posture. It was found that guilt might be attributed to group-identity and thereby denied. Tension between a self- and other-oriented response, or between blame and sympathy, was common. It is suggested that this ambiguity reflects ideological contradictions that have been internalized. It is postulated that during periods of social change such contradictions are accentuated.
- Full Text:
- Date Issued: 1995
- Authors: Cholerton, Steven M
- Date: 1995
- Subjects: Helping behavior , Interpersonal relations , Altruism , Social ethics , College students -- South Africa -- Attitudes
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:2948 , http://hdl.handle.net/10962/d1002457 , Helping behavior , Interpersonal relations , Altruism , Social ethics , College students -- South Africa -- Attitudes
- Description: The central aim of this study was to conduct a qualitative exploration of the prosocial inclinations possessed by young South African students. The literature review argues that traditional approaches to moral responding separate the individual from the social. An alternative approach that reinstates language and ideology is delineated. It is argued that such a paradigm is most appropriate to a study of prosocial responding during a period of social change. Hypothetical moral dilemmas were administered to twenty-nine students. Six students were selected and each was interviewed on two separate occasions. In this way six case studies were developed. The methodological traditions of phenomenology and hermeneutics were employed to analyze the protocols and subsequent interviews. Seven themes descriptive of a moral response were identified. These consisted of moral reasoning, empathy, mood, guilt, alienation, a sense of group-identity, and ambiguity regarding the relative interests of self versus other. These themes are fully discussed in terms of the literature. It is concluded that moral reasoning may be insufficient to motivate prosocial behaviour. Conventional moral narratives may be appropriated in order to make sense of conflicting emotions. Empathy was identified as a necessary but not sufficient condition for a prosocial response. Empathy might translate into either sympathy or personal distress. Mood was found to largely dictate attentional focus. Alienation was found to be a defensive formulation that inhibits the emergence of sympathy. Guilt might precipitate an alienated posture. It was found that guilt might be attributed to group-identity and thereby denied. Tension between a self- and other-oriented response, or between blame and sympathy, was common. It is suggested that this ambiguity reflects ideological contradictions that have been internalized. It is postulated that during periods of social change such contradictions are accentuated.
- Full Text:
- Date Issued: 1995
Calibration and interpretation of A 2.3 GHz continuum survey
- Authors: Greybe, Andrew
- Date: 1984
- Subjects: Radio astronomy , Astronomical observatories , Galaxies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5502 , http://hdl.handle.net/10962/d1007210 , Radio astronomy , Astronomical observatories , Galaxies
- Description: This thesis continues the Rhodes 2.3 GHz Survey of the Southern Sky. It consists of two parts : a data processing part and an astronomical analysis part. In the data processing part the data for the regions 4HR to 15HR, -80° to -61° and 12HR to 23HR . -27° to -7° are presented in contour map format. A beam pattern of the Hartebeesthoek telescope at 13 cm is constructed from drift scans of the radio source TAU A. This is used to investigate the data filtering techniques applied to the Rhodes Survey. It is proposed that a set of widely spaced scans which have been referred to the South Celestial Pole can provide a single calibrated baselevel for the Rhodes Survey. The observing technique and the necessary reduction programs to create a coarse grid of antenna temperatures of the Southern Sky using these observation are developed. Preliminary results for this technique are presented as a map of the region 18HR to 6HR, 90° to 30° with a 5°x5° resolution. On the astronomical side two studies are undertaken. The region 13HR to 23HR, -61° to -7° is searched for large extended areas of emission. 7 features occurring at intermediate galactic latitudes are found. They are interpreted as follows: one of them is the classical HII region surrounding the star Zeta Ophiuchi (l",b")=(6.7°,22.4°), and the rest are combinations of thermal and nonthermal emission from galactic features. The galactic equator profile for 24°> L > -58° is studied. It is dominated by a plateau of emission for L < -26°. This is interpreted as a combination of thermal and nonthermal radiation emitted by a ring of gas symmetric about the galactic centre with a radius of 4 - 6 kpc.
- Full Text:
- Date Issued: 1984
- Authors: Greybe, Andrew
- Date: 1984
- Subjects: Radio astronomy , Astronomical observatories , Galaxies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5502 , http://hdl.handle.net/10962/d1007210 , Radio astronomy , Astronomical observatories , Galaxies
- Description: This thesis continues the Rhodes 2.3 GHz Survey of the Southern Sky. It consists of two parts : a data processing part and an astronomical analysis part. In the data processing part the data for the regions 4HR to 15HR, -80° to -61° and 12HR to 23HR . -27° to -7° are presented in contour map format. A beam pattern of the Hartebeesthoek telescope at 13 cm is constructed from drift scans of the radio source TAU A. This is used to investigate the data filtering techniques applied to the Rhodes Survey. It is proposed that a set of widely spaced scans which have been referred to the South Celestial Pole can provide a single calibrated baselevel for the Rhodes Survey. The observing technique and the necessary reduction programs to create a coarse grid of antenna temperatures of the Southern Sky using these observation are developed. Preliminary results for this technique are presented as a map of the region 18HR to 6HR, 90° to 30° with a 5°x5° resolution. On the astronomical side two studies are undertaken. The region 13HR to 23HR, -61° to -7° is searched for large extended areas of emission. 7 features occurring at intermediate galactic latitudes are found. They are interpreted as follows: one of them is the classical HII region surrounding the star Zeta Ophiuchi (l",b")=(6.7°,22.4°), and the rest are combinations of thermal and nonthermal emission from galactic features. The galactic equator profile for 24°> L > -58° is studied. It is dominated by a plateau of emission for L < -26°. This is interpreted as a combination of thermal and nonthermal radiation emitted by a ring of gas symmetric about the galactic centre with a radius of 4 - 6 kpc.
- Full Text:
- Date Issued: 1984
The London Missionary Society and education
- Authors: George, Ambrose C
- Date: 1983
- Subjects: London Missionary Society -- History Black people -- Education -- South Africa -- Western Cape -- History Missions -- South Africa -- Educational work -- History
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1883 , http://hdl.handle.net/10962/d1005910
- Full Text:
- Date Issued: 1983
- Authors: George, Ambrose C
- Date: 1983
- Subjects: London Missionary Society -- History Black people -- Education -- South Africa -- Western Cape -- History Missions -- South Africa -- Educational work -- History
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1883 , http://hdl.handle.net/10962/d1005910
- Full Text:
- Date Issued: 1983
Accident liability and primary process thinking : a study in ego psychology
- Authors: Nell, Oelrich
- Date: 1975
- Subjects: Automobile drivers -- Psychology , Ego (Psychology) , Traffic safety -- South Africa -- Psychological aspects , Liability for traffic accidents -- South Africa , Traffic accidents -- South Africa -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3220 , http://hdl.handle.net/10962/d1012950
- Description: Serious efforts must be made to combat the high accident rate on the roads in the Republic of South Africa. The same spirit which exists in the field of medicine when there are evidences that an epidemic is beginning to take its toll, must come into being amongst those who are concerned with traffic and its problems. The public itself needs to become more aware of road safety. Many associations and institutions have been created to assist with the inculcation of the road safety ideal. The National Road Safety Council, which creates opportunities for investigation into aspects of road safety must continue to expand its sphere of influence. The research project contained on the following pages represents an attempt to contribute to the human factor in traffic safety, particularly by making a closer study of the driver of the motor vehicle. The writer is concerned with the carnage that is caused by road accidents. His previous study of personality and particularly of the projective techniques of assessment has prompted a consideration of the problem.
- Full Text:
- Date Issued: 1975
- Authors: Nell, Oelrich
- Date: 1975
- Subjects: Automobile drivers -- Psychology , Ego (Psychology) , Traffic safety -- South Africa -- Psychological aspects , Liability for traffic accidents -- South Africa , Traffic accidents -- South Africa -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3220 , http://hdl.handle.net/10962/d1012950
- Description: Serious efforts must be made to combat the high accident rate on the roads in the Republic of South Africa. The same spirit which exists in the field of medicine when there are evidences that an epidemic is beginning to take its toll, must come into being amongst those who are concerned with traffic and its problems. The public itself needs to become more aware of road safety. Many associations and institutions have been created to assist with the inculcation of the road safety ideal. The National Road Safety Council, which creates opportunities for investigation into aspects of road safety must continue to expand its sphere of influence. The research project contained on the following pages represents an attempt to contribute to the human factor in traffic safety, particularly by making a closer study of the driver of the motor vehicle. The writer is concerned with the carnage that is caused by road accidents. His previous study of personality and particularly of the projective techniques of assessment has prompted a consideration of the problem.
- Full Text:
- Date Issued: 1975
The classical guitar : a study in structural, technical and musical evolution
- Authors: Nock, Howard James
- Date: 1974
- Subjects: Guitar , Guitar -- Construction
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2687 , http://hdl.handle.net/10962/d1012966
- Description: Although complete works have been written dealing with the structural development of the guitar, to the best of my knowledge no attempt has yet been made to incorporate in one work an account in which structure, playing technique and musical style are correlated. Therefore the aim of this work has been to provide a compendium on these three main aspects of the historical development of the guitar ... The object of Part I is to try and establish the mainstream of the development of the guitar from the earliest beginnings of string instruments to the present day. Since little information and evidence of early instruments (i.e. before 1500 A.D.) is available, it has been necessary to formulate theories on how these developments may have taken place. Intro., p. 1.
- Full Text:
- Date Issued: 1974
- Authors: Nock, Howard James
- Date: 1974
- Subjects: Guitar , Guitar -- Construction
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2687 , http://hdl.handle.net/10962/d1012966
- Description: Although complete works have been written dealing with the structural development of the guitar, to the best of my knowledge no attempt has yet been made to incorporate in one work an account in which structure, playing technique and musical style are correlated. Therefore the aim of this work has been to provide a compendium on these three main aspects of the historical development of the guitar ... The object of Part I is to try and establish the mainstream of the development of the guitar from the earliest beginnings of string instruments to the present day. Since little information and evidence of early instruments (i.e. before 1500 A.D.) is available, it has been necessary to formulate theories on how these developments may have taken place. Intro., p. 1.
- Full Text:
- Date Issued: 1974
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