A method for imputing economic value to ecological goods and services provided by the Knysna River
- Authors: Saunders, James Woodward
- Date: 2008
- Subjects: Ecology -- South Africa -- Knysna Fishery management -- South Africa -- Knysna Water-supply -- South Africa -- Knysna Knysna Lagoon (South Africa) Knysna (South Africa) -- Economic conditions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:773 , http://hdl.handle.net/10962/d1003894
- Description: The purpose of this thesis was to develop a method by which economic value can be imputed from an economic activity to a non-market ecological function or service which contributes to that economic activity. The Knysna River in South Africa was chosen as the ecological function which supported three economic activities from which value was to be imputed; these were the Knysna Municipal Water Supply, Fish Production in the Knysna Estuary and Production of Indigenous Forest within the Knysna Catchment. Three underlying assumptions and two functional operations were required in order to implement the suggested method. The underlying assumptions were: - The ecological and economic activities considered are within a single catchment. - The allocation of value imputed for a specific economic activity to the ecological function or service under consideration (in this case the Knysna River) is proportional to the total contribution of ecological functions or services contributed to the economic activity. - The valuation of the economic activity for the purposes of obtaining a price-quantity point on a demand function is to be full cost pricing with no producer surplus. The two functional requirements were: - Diagram or map the linkages between an economic activity and the supporting ecological functions. - Determine the consumer surplus related to an incremental change in quantity under a demand function where the original price and quantity are known. A value from each of the economic activities was imputed to the Knysna River. However, the method was not tested. Nonetheless applying the equations and collecting the required data allowed several methodological needs to be clearly pointed out. The most acute deficiency was difficulty in obtaining secondary data from governmental agencies, commercial representatives and existing published academic research to ensure a robust price. Also, scientific information was not sufficiently available for allocating ecological contributions to the economic activities. Even with the shortage of credible data the method appears to allow non-market ecological functions to be valued in context of an existing economic system.
- Full Text:
- Authors: Saunders, James Woodward
- Date: 2008
- Subjects: Ecology -- South Africa -- Knysna Fishery management -- South Africa -- Knysna Water-supply -- South Africa -- Knysna Knysna Lagoon (South Africa) Knysna (South Africa) -- Economic conditions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:773 , http://hdl.handle.net/10962/d1003894
- Description: The purpose of this thesis was to develop a method by which economic value can be imputed from an economic activity to a non-market ecological function or service which contributes to that economic activity. The Knysna River in South Africa was chosen as the ecological function which supported three economic activities from which value was to be imputed; these were the Knysna Municipal Water Supply, Fish Production in the Knysna Estuary and Production of Indigenous Forest within the Knysna Catchment. Three underlying assumptions and two functional operations were required in order to implement the suggested method. The underlying assumptions were: - The ecological and economic activities considered are within a single catchment. - The allocation of value imputed for a specific economic activity to the ecological function or service under consideration (in this case the Knysna River) is proportional to the total contribution of ecological functions or services contributed to the economic activity. - The valuation of the economic activity for the purposes of obtaining a price-quantity point on a demand function is to be full cost pricing with no producer surplus. The two functional requirements were: - Diagram or map the linkages between an economic activity and the supporting ecological functions. - Determine the consumer surplus related to an incremental change in quantity under a demand function where the original price and quantity are known. A value from each of the economic activities was imputed to the Knysna River. However, the method was not tested. Nonetheless applying the equations and collecting the required data allowed several methodological needs to be clearly pointed out. The most acute deficiency was difficulty in obtaining secondary data from governmental agencies, commercial representatives and existing published academic research to ensure a robust price. Also, scientific information was not sufficiently available for allocating ecological contributions to the economic activities. Even with the shortage of credible data the method appears to allow non-market ecological functions to be valued in context of an existing economic system.
- Full Text:
A molecular analysis of the Afrotropical Baetidae
- Gattolliat, J L, Monaghan, M T, Sartori, Michel, Elouard, J M, Barber-James, Helen M, Derleth, P, Glaizot, Olivier, de Moor, Ferdy C, Vogler, Alfred P
- Authors: Gattolliat, J L , Monaghan, M T , Sartori, Michel , Elouard, J M , Barber-James, Helen M , Derleth, P , Glaizot, Olivier , de Moor, Ferdy C , Vogler, Alfred P
- Date: 2008
- Language: English
- Type: Text
- Identifier: vital:528 , http://hdl.handle.net/10962/d1008393
- Description: Recent work on the Afrotropical Baetidae has resulted in a number of important taxonomic changes: several polyphyletic genera have been split and more than 30 new Afrotropical genera have been established. In order to test their phylogenetic relevance and to clarify the suprageneric relationships, we reconstructed the first comprehensive molecular phylogeny of the Afrotropical Baetidae. We sequenced a total of ca. 2300 bp from nuclear (18S) and mitochondrial (12S and 16S) gene regions from 65 species belonging to 26 genera. We used three different approaches of phylogeny reconstruction: direct optimization, maximum parsimony and maximum likelihood. The molecular reconstruction indicates the Afrotropical Baetidae require a global revision at a generic as well as suprageneric level. Only four of the 12 genera were monophyletic when represented by more than one species in the analysis. Historically, two conflicting concepts of the suprageneric classification of Afrotropical Baetidae were proposed. One was based on the gathering of sister genera into complexes and the other on the division of the family into a restricted number of subfamilies. According to our reconstruction, neither is completely satisfactory: the major complexes of genera present in Africa are either paraphyletic or polyphyletic and the division of the Afrotropical Baetidae into two subfamilies is probably too simplified.
- Full Text:
- Authors: Gattolliat, J L , Monaghan, M T , Sartori, Michel , Elouard, J M , Barber-James, Helen M , Derleth, P , Glaizot, Olivier , de Moor, Ferdy C , Vogler, Alfred P
- Date: 2008
- Language: English
- Type: Text
- Identifier: vital:528 , http://hdl.handle.net/10962/d1008393
- Description: Recent work on the Afrotropical Baetidae has resulted in a number of important taxonomic changes: several polyphyletic genera have been split and more than 30 new Afrotropical genera have been established. In order to test their phylogenetic relevance and to clarify the suprageneric relationships, we reconstructed the first comprehensive molecular phylogeny of the Afrotropical Baetidae. We sequenced a total of ca. 2300 bp from nuclear (18S) and mitochondrial (12S and 16S) gene regions from 65 species belonging to 26 genera. We used three different approaches of phylogeny reconstruction: direct optimization, maximum parsimony and maximum likelihood. The molecular reconstruction indicates the Afrotropical Baetidae require a global revision at a generic as well as suprageneric level. Only four of the 12 genera were monophyletic when represented by more than one species in the analysis. Historically, two conflicting concepts of the suprageneric classification of Afrotropical Baetidae were proposed. One was based on the gathering of sister genera into complexes and the other on the division of the family into a restricted number of subfamilies. According to our reconstruction, neither is completely satisfactory: the major complexes of genera present in Africa are either paraphyletic or polyphyletic and the division of the Afrotropical Baetidae into two subfamilies is probably too simplified.
- Full Text:
A phenomenological case study of a lecturer's understanding of himself as an assessor
- Authors: Grant, Rosemary
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6087 , http://hdl.handle.net/10962/d1008582
- Description: Based on the findings of research conducted as part of a doctoral study aimed at obtaining an understanding of what it means to be an assessor in higher education, this paper outlines the experience of an individual lecturer at a South African university and describes the meaning he makes of his practice as an assessor within the context of a changing understanding of the nature and purpose of higher education. Making a case for personal agency and innovation as critical qualities in the assessment endeavour, the researcher suggests that, in contrast to a view of education increasingly focused on standardization, accountability and outcomes, student assessment is essentially a human encounter in which the humanity and emotions of both lecturer and student need to be acknowledged.
- Full Text:
- Authors: Grant, Rosemary
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6087 , http://hdl.handle.net/10962/d1008582
- Description: Based on the findings of research conducted as part of a doctoral study aimed at obtaining an understanding of what it means to be an assessor in higher education, this paper outlines the experience of an individual lecturer at a South African university and describes the meaning he makes of his practice as an assessor within the context of a changing understanding of the nature and purpose of higher education. Making a case for personal agency and innovation as critical qualities in the assessment endeavour, the researcher suggests that, in contrast to a view of education increasingly focused on standardization, accountability and outcomes, student assessment is essentially a human encounter in which the humanity and emotions of both lecturer and student need to be acknowledged.
- Full Text:
A preliminary investigation into the use of biomarkers and a fish community index to assess estuarine health in selected Eastern Cape estuaries
- Authors: Richardson, Naomi
- Date: 2008
- Subjects: Fish communities -- South Africa -- Eastern Cape Estuarine fishes -- South Africa -- Eastern Cape Estuarine health -- South Africa -- Eastern Cape Estuaries -- South Africa -- Eastern Cape -- Management Coastal zone management -- South Africa -- Eastern Cape Environmental monitoring -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5348 , http://hdl.handle.net/10962/d1007480
- Description: The aims of this study were to determine the potential use of biomarkers at multiple levels of biological organisation together with a fish community bioindicator to assess the estuarine health status of three temporarily open/closed estuaries. The estuaries investigated were the East Kleinemonde (EK), Old Woman's (OW) and Mtana (MTN), all of which are situated in the Eastern Cape Province. Three biomarkers, the acetylcholinesterase (AChE) assay, lipid peroxidation (LPx) assay, liver histopathology and a condition factor were used to determine sub-organism health and one bioindicator, the Estuarine Fish Community Index (EFCI), was used as a bioindicator of community health. The estuarine-dependent marine species Rhabdosargus holubi was selected as an indicator species for the sub-organism level analyses. The results from the community analyses indicated that the EK and OW estuaries were in 'good' condition, while the MTN was found to be in 'moderate' condition. Histological analyses revealed that R. holubi from all three estuaries showed signs of pathological changes to the liver, with the fish from the MTN eliciting the highest occurrence of these changes. The LPx assay found that R. holubi from both the OW and MTN showed signs of oxidative damage in the liver tissue, but those from the EK did not appear to be affected. The AChE assay showed that only the fish from the OW had been affected by anticholinesterase compounds. A laboratory study was undertaken using R. holubi as a positive control for the AChE and LPx assay. The fish were exposed to 3 μg/L chlorpyrifos, a known cholinesterase inhibitor, for six hours and their tissues were examined for changes to LPx levels and AChE activities. AChE activity was significantly inhibited (Mann Whitney U test, Z = 3.65, n = 38, P < 0.001) by the exposure, but LPx levels were not significantly affected. A composite index incorporating the biomarkers at different biological levels of organisation was developed. The index was designed to assist managers and scientists to determine whether the ichthyofauna of a system was being affected by environmental stressors and what management interventions could be undertaken to ameliorate the water quality in an estuary. The index was applied to the three estuaries investigated during the present study and both the OW and MTN were assessed to be in need of immediate management intervention. The fish in the OW were found to be stressed at all the sub-organism levels measured and the reason for this was hypothesised to be as a result of golf course activities in this adjacent estuary. A number of management actions are proposed to reduce the sub-organism stress observed in the fish from the OW. The livers of fish from the MTN were shown to be under stress; however the causative agent of this stress was unknown because there is no formal development in the MTN catchment. However, a possible contaminant source is proposed and management interventions to alleviate the stress on the biota of the MTN are suggested. The EK does not require immediate management intervention, however, continuous routine monitoring is recommended to ensure that conditions do not deteriorate. Shortcomings of the index were outlined and a number of suggestions were made in terms of other measures of biological health which could be incorporated into the index.
- Full Text:
- Authors: Richardson, Naomi
- Date: 2008
- Subjects: Fish communities -- South Africa -- Eastern Cape Estuarine fishes -- South Africa -- Eastern Cape Estuarine health -- South Africa -- Eastern Cape Estuaries -- South Africa -- Eastern Cape -- Management Coastal zone management -- South Africa -- Eastern Cape Environmental monitoring -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5348 , http://hdl.handle.net/10962/d1007480
- Description: The aims of this study were to determine the potential use of biomarkers at multiple levels of biological organisation together with a fish community bioindicator to assess the estuarine health status of three temporarily open/closed estuaries. The estuaries investigated were the East Kleinemonde (EK), Old Woman's (OW) and Mtana (MTN), all of which are situated in the Eastern Cape Province. Three biomarkers, the acetylcholinesterase (AChE) assay, lipid peroxidation (LPx) assay, liver histopathology and a condition factor were used to determine sub-organism health and one bioindicator, the Estuarine Fish Community Index (EFCI), was used as a bioindicator of community health. The estuarine-dependent marine species Rhabdosargus holubi was selected as an indicator species for the sub-organism level analyses. The results from the community analyses indicated that the EK and OW estuaries were in 'good' condition, while the MTN was found to be in 'moderate' condition. Histological analyses revealed that R. holubi from all three estuaries showed signs of pathological changes to the liver, with the fish from the MTN eliciting the highest occurrence of these changes. The LPx assay found that R. holubi from both the OW and MTN showed signs of oxidative damage in the liver tissue, but those from the EK did not appear to be affected. The AChE assay showed that only the fish from the OW had been affected by anticholinesterase compounds. A laboratory study was undertaken using R. holubi as a positive control for the AChE and LPx assay. The fish were exposed to 3 μg/L chlorpyrifos, a known cholinesterase inhibitor, for six hours and their tissues were examined for changes to LPx levels and AChE activities. AChE activity was significantly inhibited (Mann Whitney U test, Z = 3.65, n = 38, P < 0.001) by the exposure, but LPx levels were not significantly affected. A composite index incorporating the biomarkers at different biological levels of organisation was developed. The index was designed to assist managers and scientists to determine whether the ichthyofauna of a system was being affected by environmental stressors and what management interventions could be undertaken to ameliorate the water quality in an estuary. The index was applied to the three estuaries investigated during the present study and both the OW and MTN were assessed to be in need of immediate management intervention. The fish in the OW were found to be stressed at all the sub-organism levels measured and the reason for this was hypothesised to be as a result of golf course activities in this adjacent estuary. A number of management actions are proposed to reduce the sub-organism stress observed in the fish from the OW. The livers of fish from the MTN were shown to be under stress; however the causative agent of this stress was unknown because there is no formal development in the MTN catchment. However, a possible contaminant source is proposed and management interventions to alleviate the stress on the biota of the MTN are suggested. The EK does not require immediate management intervention, however, continuous routine monitoring is recommended to ensure that conditions do not deteriorate. Shortcomings of the index were outlined and a number of suggestions were made in terms of other measures of biological health which could be incorporated into the index.
- Full Text:
A preliminary investigation of spinal kinematics during sugar cane harvesting
- Authors: Todd, Andrew I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6759 , http://hdl.handle.net/10962/d1009462
- Description: The sugar cane industry forms a significant portion of the South African economy, and unlike many other countries the harvesting of sugar cane in South Africa remains manual in nature. The focus of the present study was therefore on the assessment of spinal kinematics (range of motion, velocities and accelerations in all three cardinal planes) during the harvesting process. Eight workers were recruited from the Illovo Esperanza farm in Kwa-zulu Natal as subjects for the study. The experimental protocol was conducted in situ and required subjects to cut the sugar cane using specially modified knives as they would under normal harvesting conditions. The motion performance was quantified using the lumbar motion monitor (LMM), a triaxial electrogoniometer. Results indicate that the harvesting of sugar cane places excessive demands on the spine. During cutting, subjects were required to maintain the spine in a high degree of flexion throughout the task which also demonstrated significant twisting and lateral bending. Of particular concern were the high lateral velocities (ranging between 50 and 90 m.s-1), as this is a key risk factor in the development of lower back pain. It is evident from these results that new techniques of harvesting sugar cane are essential to reduce the rate of injury within this industry.
- Full Text:
- Authors: Todd, Andrew I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6759 , http://hdl.handle.net/10962/d1009462
- Description: The sugar cane industry forms a significant portion of the South African economy, and unlike many other countries the harvesting of sugar cane in South Africa remains manual in nature. The focus of the present study was therefore on the assessment of spinal kinematics (range of motion, velocities and accelerations in all three cardinal planes) during the harvesting process. Eight workers were recruited from the Illovo Esperanza farm in Kwa-zulu Natal as subjects for the study. The experimental protocol was conducted in situ and required subjects to cut the sugar cane using specially modified knives as they would under normal harvesting conditions. The motion performance was quantified using the lumbar motion monitor (LMM), a triaxial electrogoniometer. Results indicate that the harvesting of sugar cane places excessive demands on the spine. During cutting, subjects were required to maintain the spine in a high degree of flexion throughout the task which also demonstrated significant twisting and lateral bending. Of particular concern were the high lateral velocities (ranging between 50 and 90 m.s-1), as this is a key risk factor in the development of lower back pain. It is evident from these results that new techniques of harvesting sugar cane are essential to reduce the rate of injury within this industry.
- Full Text:
A preliminary survey of the estuaries on the south coast of South Africa, Cape St Blaize, Mossel Bay - Robberg Peninsula, Plettenberg Bay, with particular reference to the fish fauna
- James, Nicola C, Harrison, T D
- Authors: James, Nicola C , Harrison, T D
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7141 , http://hdl.handle.net/10962/d1011834
- Description: The coastal river systems on the south coast of South Africa from Cape St Blaize to Robberg Peninsula were surveyed during October and November 1994. The ichthyofaunal and physico-chemical characteristics of each system are presented and their suitability as estuarine nursery areas is discussed. Five systems (Rooi, Meul, Grooteiland, Kranshoek and Crooks) are outlets of small coastal streams and probably provide little or no habitat for either resident estuarine or migrant marine fishes owing to their small size. Four systems (Maalgate, Gwaing, Skaapkop and Kaaimans) are located within deeply incised valleys and have a permanent connection with the sea. The amount of marginal and intertidal habitat available to fishes, however, is limited due to their morphology. Six systems (Hartenbos, Groot Brak, Touw, Swartvlei, Goukamma and Noetsie) are intermittently open to the sea. Although the Touw and Swartvlei are connected to coastal lake systems, flow within these estuaries is not sufficient to prevent the build up of a sand barrier at the mouth. The Hartenbos, Groot Brak, Goukamma, and Noetsie are also periodically closed by a sand bar. The construction of a dam in the lower catchment of the Groot Brak has affected the hydrology of the system. The two remaining estuaries (Klein Brak and Knysna) are permanently open. In addition to strong tidal currents, the fixing of the mouth of the Knysna Estuary between rocky headlands also serves to maintain a permanent connection with the sea. Mugilidae and Sparidae were represented by the greatest number of species, and also dominated catches numerically and by mass. The fish fauna of all the estuaries surveyed were dominated by the juveniles of estuarine-dependent marine species and estuarine-resident species were also well represented in catches. The estuaries surveyed provide a vital habitat for both marine migrant species and resident species, most of which are endemic to the region.
- Full Text:
- Authors: James, Nicola C , Harrison, T D
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7141 , http://hdl.handle.net/10962/d1011834
- Description: The coastal river systems on the south coast of South Africa from Cape St Blaize to Robberg Peninsula were surveyed during October and November 1994. The ichthyofaunal and physico-chemical characteristics of each system are presented and their suitability as estuarine nursery areas is discussed. Five systems (Rooi, Meul, Grooteiland, Kranshoek and Crooks) are outlets of small coastal streams and probably provide little or no habitat for either resident estuarine or migrant marine fishes owing to their small size. Four systems (Maalgate, Gwaing, Skaapkop and Kaaimans) are located within deeply incised valleys and have a permanent connection with the sea. The amount of marginal and intertidal habitat available to fishes, however, is limited due to their morphology. Six systems (Hartenbos, Groot Brak, Touw, Swartvlei, Goukamma and Noetsie) are intermittently open to the sea. Although the Touw and Swartvlei are connected to coastal lake systems, flow within these estuaries is not sufficient to prevent the build up of a sand barrier at the mouth. The Hartenbos, Groot Brak, Goukamma, and Noetsie are also periodically closed by a sand bar. The construction of a dam in the lower catchment of the Groot Brak has affected the hydrology of the system. The two remaining estuaries (Klein Brak and Knysna) are permanently open. In addition to strong tidal currents, the fixing of the mouth of the Knysna Estuary between rocky headlands also serves to maintain a permanent connection with the sea. Mugilidae and Sparidae were represented by the greatest number of species, and also dominated catches numerically and by mass. The fish fauna of all the estuaries surveyed were dominated by the juveniles of estuarine-dependent marine species and estuarine-resident species were also well represented in catches. The estuaries surveyed provide a vital habitat for both marine migrant species and resident species, most of which are endemic to the region.
- Full Text:
A stable isotope approach to trophic ecology resolving food webs in intertidal ecosystems
- Authors: Hill, Jaclyn Marie
- Date: 2008
- Subjects: Stable isotopes Food chains (Ecology) Stable isotopes in ecological research Intertidal ecology Mussels -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5771 , http://hdl.handle.net/10962/d1005459
- Description: There are broad differences in regional oceanography and primary production around the South African coast, which we might expect to give rise to major differences in trophic pathways. δ⁻¹³C and δ⁻¹⁵N isotopic ratios of suspended particulate matter (SPM), mussels, various intertidal consumers and common macroalgae along the South African coastline were explored using stable isotope analysis to investigate biogeographic and temporal variability of isotopic signatures of marine intertidal consumers and their food sources around the coast of South Africa, with a focus on evaluating the dependence of intertidal mussels on phytoplankton and macroalgal-derived organic carbon. Isotopic equilibration rates of four mussel tissues were determined through laboratory feeding experiments, which established that adductor tissue had the slowest isotopic turnover rate, and was subsequently used as an indication of overall mussel diet. Biogeographic, temporal and nearshore/offshore trends of isotopic ratios of SPM were investigated along 10km transects perpendicular to the coast and SPM exhibited overall trends of carbon depletion when moving from west to east along the coastline and from nearshore to offshore water, in both cases suggesting a shift from macrophyte detritus to a phytoplankton signature. δ⁻¹³C signatures of SPM also revealed temporal and biogeographic variation that had strong ties to local oceanography, being closely correlated to regional hydrographic features and tidal influences. Mixing models indicated filter feeders demonstrated over 50% dependence on nearshore SPM for organic carbon and it was possible to categorize them into geographic groups based on their carbon and nitrogen signatures, suggesting biogeographic shifts in resources. Biogeographic shifts in diet were also seen in some grazers. Difficulties in relating macroalgae to mussel diet led to investigations into the isotopic changes associated with macroalgal decomposition. Variation in photosynthetic fractionation, leaching and microbial mineralization are believed to have resulted from species-specific patterns of degradation. Although the strong links between carbon signatures and local oceanography indicate that stable isotope analysis is a powerful tool for the study of water mixing and coastal hydrography in relation to food-web analyses, substantial variation in fractionation of primary consumers, along with different periods of time integration between consumers and their food sources must be considered in future studies, to resolve trophic links in marine food webs successfully.
- Full Text:
- Authors: Hill, Jaclyn Marie
- Date: 2008
- Subjects: Stable isotopes Food chains (Ecology) Stable isotopes in ecological research Intertidal ecology Mussels -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5771 , http://hdl.handle.net/10962/d1005459
- Description: There are broad differences in regional oceanography and primary production around the South African coast, which we might expect to give rise to major differences in trophic pathways. δ⁻¹³C and δ⁻¹⁵N isotopic ratios of suspended particulate matter (SPM), mussels, various intertidal consumers and common macroalgae along the South African coastline were explored using stable isotope analysis to investigate biogeographic and temporal variability of isotopic signatures of marine intertidal consumers and their food sources around the coast of South Africa, with a focus on evaluating the dependence of intertidal mussels on phytoplankton and macroalgal-derived organic carbon. Isotopic equilibration rates of four mussel tissues were determined through laboratory feeding experiments, which established that adductor tissue had the slowest isotopic turnover rate, and was subsequently used as an indication of overall mussel diet. Biogeographic, temporal and nearshore/offshore trends of isotopic ratios of SPM were investigated along 10km transects perpendicular to the coast and SPM exhibited overall trends of carbon depletion when moving from west to east along the coastline and from nearshore to offshore water, in both cases suggesting a shift from macrophyte detritus to a phytoplankton signature. δ⁻¹³C signatures of SPM also revealed temporal and biogeographic variation that had strong ties to local oceanography, being closely correlated to regional hydrographic features and tidal influences. Mixing models indicated filter feeders demonstrated over 50% dependence on nearshore SPM for organic carbon and it was possible to categorize them into geographic groups based on their carbon and nitrogen signatures, suggesting biogeographic shifts in resources. Biogeographic shifts in diet were also seen in some grazers. Difficulties in relating macroalgae to mussel diet led to investigations into the isotopic changes associated with macroalgal decomposition. Variation in photosynthetic fractionation, leaching and microbial mineralization are believed to have resulted from species-specific patterns of degradation. Although the strong links between carbon signatures and local oceanography indicate that stable isotope analysis is a powerful tool for the study of water mixing and coastal hydrography in relation to food-web analyses, substantial variation in fractionation of primary consumers, along with different periods of time integration between consumers and their food sources must be considered in future studies, to resolve trophic links in marine food webs successfully.
- Full Text:
A study of professionalism and the professionalisation of journalists in Uganda from 1995 to 2008
- Authors: Mayiga, John Bosco
- Date: 2008
- Subjects: Journalists -- Uganda Journalism -- Political aspects -- Uganda Mass media -- Political aspects -- Uganda Journalism -- Sociological aspects -- Uganda Journalism, Commercial -- Uganda
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3461 , http://hdl.handle.net/10962/d1002916
- Description: This study seeks to examine how Ugandan journalists’ and politicians’ views on journalism professionalisation in Uganda relate to the broad theoretical arguments about professionalism within sociology and media studies. It also seeks to examine how such views impact on the democratic role of the media. The study finds out that there are two sets of distinct ideas on journalism professionalisation. The idea espoused by politicians is statutory professionalisation in which the state plays a major role through regulation and control, hence professionalisation is seen primarily as a control system. On the other hand, journalists perceive professionalisation as nurtured by voluntarily and socially inculcated professional values, hence as a value system. The study however, finds that both sets of understandings have their own complexities. While the statutory approach has complexities like how core elements of professionalism such as professional values can be imposed through legislation, the voluntary approach to professionalism also exhibits tensions within, especially stemming from the relationship between the professional and the news organisation regarding what constitutes professionalism. The study concludes that both sets of ideas have implications for the democratic role of the media, with both perceptions of professionalism curtailing this role. Statutory professionalisation in the Ugandan political context where the state is the dominant institution brings media institutions within its control, which leads to suppression of content of democratic value through a number of means. On the other hand, the self-regulatory perception does not protect media professionalism from the assault of commercial imperatives, especially when fused with state patronage in regard to broadcasting licences and placement of advertising.
- Full Text:
- Authors: Mayiga, John Bosco
- Date: 2008
- Subjects: Journalists -- Uganda Journalism -- Political aspects -- Uganda Mass media -- Political aspects -- Uganda Journalism -- Sociological aspects -- Uganda Journalism, Commercial -- Uganda
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3461 , http://hdl.handle.net/10962/d1002916
- Description: This study seeks to examine how Ugandan journalists’ and politicians’ views on journalism professionalisation in Uganda relate to the broad theoretical arguments about professionalism within sociology and media studies. It also seeks to examine how such views impact on the democratic role of the media. The study finds out that there are two sets of distinct ideas on journalism professionalisation. The idea espoused by politicians is statutory professionalisation in which the state plays a major role through regulation and control, hence professionalisation is seen primarily as a control system. On the other hand, journalists perceive professionalisation as nurtured by voluntarily and socially inculcated professional values, hence as a value system. The study however, finds that both sets of understandings have their own complexities. While the statutory approach has complexities like how core elements of professionalism such as professional values can be imposed through legislation, the voluntary approach to professionalism also exhibits tensions within, especially stemming from the relationship between the professional and the news organisation regarding what constitutes professionalism. The study concludes that both sets of ideas have implications for the democratic role of the media, with both perceptions of professionalism curtailing this role. Statutory professionalisation in the Ugandan political context where the state is the dominant institution brings media institutions within its control, which leads to suppression of content of democratic value through a number of means. On the other hand, the self-regulatory perception does not protect media professionalism from the assault of commercial imperatives, especially when fused with state patronage in regard to broadcasting licences and placement of advertising.
- Full Text:
A study of the Amathole District Municipality's settlement plan in the light of the land reform and spatial planning measures
- Authors: Zenzile, Mlamli Lennox
- Date: 2008
- Subjects: Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Land use -- Planning -- South Africa , Restitution -- South Africa -- Eastern Cape , Compensation (Law) -- South Africa -- Eastern Cape , Human rights -- South Africa -- Eastern Cape , Right of property -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3700 , http://hdl.handle.net/10962/d1003215 , Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Land use -- Planning -- South Africa , Restitution -- South Africa -- Eastern Cape , Compensation (Law) -- South Africa -- Eastern Cape , Human rights -- South Africa -- Eastern Cape , Right of property -- South Africa -- Eastern Cape
- Description: This study concerns the analysis of policy, and the statutory and regulatory impact of spatial planning on the land reform programme with emphasis on the land reform settlement plan (LSRP) of the Amathole District Municipality (ADM). There is a brief historical overview of the effect of the policy of spatial segregation in both rural and urban areas of the ADM. This study demonstrates, inter alia, the challenges faced by the ADM in both consolidating and physically integrating communities that were hitherto divided across racial lines. The critical question is whether the ADM has the ability to produce a Spatial Development Framework (SDF), which will be responsive to the needs of the region and serve as a catalyst in reversing the physical distortions caused by the land-planning legislation of the apartheid past. The greatest challenge lies in meeting the developmental aspirations of the Development Facilitation Act, 1995, the Local Government: Municipal Systems Act, 2000 and the National Spatial Development Perspective, 2003. Chapter 1 deals with the purpose, research problem and the method of research, as well as the definition of terms used in this research and literature review. Chapter 2 deals with the evolution of central themes of spatial planning and land reform, spatial development plans and integrated development plans (IDPs), the alignment of Amathole SDF and Eastern Cape Spatial Development Plan and the co-ordination of spatial frameworks. Chapter 3 deals with the composition of the ADM and the evolution of the LRSP, as well as land-tenure reform programmes impacting on the Amathole Municipality region. This chapter analyses the settlement plan against spatial planning legislation, the issue of institutional arrangements and mechanisms of consolidated local planning processes. Chapter 5 deals with the thorny issue of participation of traditional leaders in municipal planning and the government’s land-reform programme. Despite the existence of legislation in this regard, implementation seems to pose some difficulties. This chapter also deals with the co-operative governance framework. Chapter 6 is a concluding chapter dealing with the gaps discovered in the Amathole Municipality in the light of existing legislation. Reference to cases is made to demonstrate the challenges confronting the ADM. One notable aspect is the issue of urban-rural dichotomy and how the two worlds are positioned in their competition for the use of space. It is evident from this research that the post-1994 policy and legislative framework and implementation machinery lacks capacity to change the current form of the apartheid city-planning paradigm, something which impacts immensely on the sustainability of the current human-settlement development programmes. Population dynamics in terms of migration are hugely driven by search for employment opportunities and better services. The efficiency and ability of the municipal spatial evelopment frameworks in directing and dictating the identification of development nodes in its juristic boundary informed by the overarching national policy and legislative framework is key in building a better South Africa.
- Full Text:
- Authors: Zenzile, Mlamli Lennox
- Date: 2008
- Subjects: Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Land use -- Planning -- South Africa , Restitution -- South Africa -- Eastern Cape , Compensation (Law) -- South Africa -- Eastern Cape , Human rights -- South Africa -- Eastern Cape , Right of property -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3700 , http://hdl.handle.net/10962/d1003215 , Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Land use -- Planning -- South Africa , Restitution -- South Africa -- Eastern Cape , Compensation (Law) -- South Africa -- Eastern Cape , Human rights -- South Africa -- Eastern Cape , Right of property -- South Africa -- Eastern Cape
- Description: This study concerns the analysis of policy, and the statutory and regulatory impact of spatial planning on the land reform programme with emphasis on the land reform settlement plan (LSRP) of the Amathole District Municipality (ADM). There is a brief historical overview of the effect of the policy of spatial segregation in both rural and urban areas of the ADM. This study demonstrates, inter alia, the challenges faced by the ADM in both consolidating and physically integrating communities that were hitherto divided across racial lines. The critical question is whether the ADM has the ability to produce a Spatial Development Framework (SDF), which will be responsive to the needs of the region and serve as a catalyst in reversing the physical distortions caused by the land-planning legislation of the apartheid past. The greatest challenge lies in meeting the developmental aspirations of the Development Facilitation Act, 1995, the Local Government: Municipal Systems Act, 2000 and the National Spatial Development Perspective, 2003. Chapter 1 deals with the purpose, research problem and the method of research, as well as the definition of terms used in this research and literature review. Chapter 2 deals with the evolution of central themes of spatial planning and land reform, spatial development plans and integrated development plans (IDPs), the alignment of Amathole SDF and Eastern Cape Spatial Development Plan and the co-ordination of spatial frameworks. Chapter 3 deals with the composition of the ADM and the evolution of the LRSP, as well as land-tenure reform programmes impacting on the Amathole Municipality region. This chapter analyses the settlement plan against spatial planning legislation, the issue of institutional arrangements and mechanisms of consolidated local planning processes. Chapter 5 deals with the thorny issue of participation of traditional leaders in municipal planning and the government’s land-reform programme. Despite the existence of legislation in this regard, implementation seems to pose some difficulties. This chapter also deals with the co-operative governance framework. Chapter 6 is a concluding chapter dealing with the gaps discovered in the Amathole Municipality in the light of existing legislation. Reference to cases is made to demonstrate the challenges confronting the ADM. One notable aspect is the issue of urban-rural dichotomy and how the two worlds are positioned in their competition for the use of space. It is evident from this research that the post-1994 policy and legislative framework and implementation machinery lacks capacity to change the current form of the apartheid city-planning paradigm, something which impacts immensely on the sustainability of the current human-settlement development programmes. Population dynamics in terms of migration are hugely driven by search for employment opportunities and better services. The efficiency and ability of the municipal spatial evelopment frameworks in directing and dictating the identification of development nodes in its juristic boundary informed by the overarching national policy and legislative framework is key in building a better South Africa.
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A study of the existence of equilibrium in mathematical economics
- Authors: Xotyeni, Zukisa Gqabi
- Date: 2008
- Subjects: Equilibrium (Economics) -- Mathematical models , Macroeconomics -- Mathematical models , Economics -- Mathematical models , Welfare economics -- Mathematical models , Lattice theory , Economics, Mathematical
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5418 , http://hdl.handle.net/10962/d1005232 , Equilibrium (Economics) -- Mathematical models , Macroeconomics -- Mathematical models , Economics -- Mathematical models , Welfare economics -- Mathematical models , Lattice theory , Economics, Mathematical
- Description: In this thesis we define and study the existence of an equilibrium situation in which producers maximize their profits relative to the production vectors in their production sets, consumers satisfy their preferences in their consumption sets under certain budget constraint, and for every commodity total demand equals total supply. This competitive equilibrium situation is referred to as the Walrasian equilibrium. The existence of this equilibrium is investigated from a various mathematical points of view. These include microeconomic theory, simplicial spaces, global analysis and lattice theory.
- Full Text:
- Authors: Xotyeni, Zukisa Gqabi
- Date: 2008
- Subjects: Equilibrium (Economics) -- Mathematical models , Macroeconomics -- Mathematical models , Economics -- Mathematical models , Welfare economics -- Mathematical models , Lattice theory , Economics, Mathematical
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5418 , http://hdl.handle.net/10962/d1005232 , Equilibrium (Economics) -- Mathematical models , Macroeconomics -- Mathematical models , Economics -- Mathematical models , Welfare economics -- Mathematical models , Lattice theory , Economics, Mathematical
- Description: In this thesis we define and study the existence of an equilibrium situation in which producers maximize their profits relative to the production vectors in their production sets, consumers satisfy their preferences in their consumption sets under certain budget constraint, and for every commodity total demand equals total supply. This competitive equilibrium situation is referred to as the Walrasian equilibrium. The existence of this equilibrium is investigated from a various mathematical points of view. These include microeconomic theory, simplicial spaces, global analysis and lattice theory.
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A survey of fruit-feeding insects and their parasitoids occurring on wild olives, Olea europaea ssp. cuspidata, in the Eastern Cape of South Africa
- Mkize, Nolwazi, Hoelmer, Kim A, Villet, Martin H
- Authors: Mkize, Nolwazi , Hoelmer, Kim A , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441694 , vital:73907 , https://doi.org/10.1080/09583150802450154
- Description: Fruits of wild olives, Olea europaea ssp. cuspidata (Wall. ex G. Don) Cif., were collected in the Eastern Cape, South Africa, during 2003–2005 to quantify levels of fruit-infesting pests and their parasitoids. Two species of Tephritidae, Bactrocera oleae (Rossi) and B. biguttula (Bezzi), were the most abundant insects recovered and were reared from most samples. Fruit infestation rates by the Bactrocera spp. were generally below 8% and over half of the infestations were under 1%. When parasitism occurred in samples with flies, levels ranged from 7 to 83%. Several species of opiine braconid wasps, Psyttalia concolor (Szépligeti), Psyttalia lounsburyi (Silvestri), and Utetes africanus (Szépligeti) and one braconine wasp, Bracon celer Szépligeti, were reared from fruits containing B. oleae and/or B. biguttula. Chalcidoid parasitoids and seed wasps included seven species of Eurytomidae (Eurytoma oleae, Eurytoma sp., and Sycophila sp.), Ormyridae (Ormyrus sp.), Torymidae (Megastigmus sp.), and Eupelmidae (Eupelmus afer and E. spermophilus). One species of moth, Palpita unionalis (Hübner) (Crambidae), was recovered in very low numbers and without parasitoids. The survey results indicate that fruit flies might not become economic pests of the nascent commercial olive industry in the Eastern Cape, and the small numbers present may be controlled to a considerable level by natural enemies.
- Full Text:
- Authors: Mkize, Nolwazi , Hoelmer, Kim A , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441694 , vital:73907 , https://doi.org/10.1080/09583150802450154
- Description: Fruits of wild olives, Olea europaea ssp. cuspidata (Wall. ex G. Don) Cif., were collected in the Eastern Cape, South Africa, during 2003–2005 to quantify levels of fruit-infesting pests and their parasitoids. Two species of Tephritidae, Bactrocera oleae (Rossi) and B. biguttula (Bezzi), were the most abundant insects recovered and were reared from most samples. Fruit infestation rates by the Bactrocera spp. were generally below 8% and over half of the infestations were under 1%. When parasitism occurred in samples with flies, levels ranged from 7 to 83%. Several species of opiine braconid wasps, Psyttalia concolor (Szépligeti), Psyttalia lounsburyi (Silvestri), and Utetes africanus (Szépligeti) and one braconine wasp, Bracon celer Szépligeti, were reared from fruits containing B. oleae and/or B. biguttula. Chalcidoid parasitoids and seed wasps included seven species of Eurytomidae (Eurytoma oleae, Eurytoma sp., and Sycophila sp.), Ormyridae (Ormyrus sp.), Torymidae (Megastigmus sp.), and Eupelmidae (Eupelmus afer and E. spermophilus). One species of moth, Palpita unionalis (Hübner) (Crambidae), was recovered in very low numbers and without parasitoids. The survey results indicate that fruit flies might not become economic pests of the nascent commercial olive industry in the Eastern Cape, and the small numbers present may be controlled to a considerable level by natural enemies.
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A symptom that defies analysis: is this simply xenophobia?.
- Authors: Kyazze, Simwogerere
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159337 , vital:40289 , https://hdl.handle.net/10520/EJC140106
- Description: On 29 January 29 2007 I travelled on an SAA flight from Entebbe International Airport in Uganda to OR Tambo International in Johannesburg. Somehow, I had forgotten, ignored or failed to travel with my Yellow Fever Certificate and an Immigration Officer let me have it.
- Full Text:
- Authors: Kyazze, Simwogerere
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159337 , vital:40289 , https://hdl.handle.net/10520/EJC140106
- Description: On 29 January 29 2007 I travelled on an SAA flight from Entebbe International Airport in Uganda to OR Tambo International in Johannesburg. Somehow, I had forgotten, ignored or failed to travel with my Yellow Fever Certificate and an Immigration Officer let me have it.
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A synopsis of the Afrotropical Tricorythidae
- Authors: Barber-James, Helen M
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:7003 , http://hdl.handle.net/10962/d1008362
- Description: The Tricorythidae of the Afrotropical Region is currently composed of five described genera, three of which are thought to be restricted to Madagascar (Madecassorythus Elouard and Oliarioniny, Ranorythus Oliarinony and Elouard, and Spinirythus Oliarinony and Elouard), one which is restricted to Africa (Dicercomyzon Demoulin), and one which is thought to be distributed on both landmasses (Tricorythus Eaton). Based on sexual dimorphism, manifest in the relative eye size of mature male and female nymphs and adults and on the structure of the genitalia of adult males, it is proposed that there are two additional genera in Africa, as yet undescribed. One of these genera is represented by a species currently placed in Tricorythus (T. discolor [Burmeister]). Several other undescribed species within South Africa have been identified as belonging to the group. A second lineage is represented by Tricorythus tinctus Kimmins, from Uganda, the only currently described species. There are also several more undescribed species of this group widespread in Africa.
- Full Text:
- Authors: Barber-James, Helen M
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:7003 , http://hdl.handle.net/10962/d1008362
- Description: The Tricorythidae of the Afrotropical Region is currently composed of five described genera, three of which are thought to be restricted to Madagascar (Madecassorythus Elouard and Oliarioniny, Ranorythus Oliarinony and Elouard, and Spinirythus Oliarinony and Elouard), one which is restricted to Africa (Dicercomyzon Demoulin), and one which is thought to be distributed on both landmasses (Tricorythus Eaton). Based on sexual dimorphism, manifest in the relative eye size of mature male and female nymphs and adults and on the structure of the genitalia of adult males, it is proposed that there are two additional genera in Africa, as yet undescribed. One of these genera is represented by a species currently placed in Tricorythus (T. discolor [Burmeister]). Several other undescribed species within South Africa have been identified as belonging to the group. A second lineage is represented by Tricorythus tinctus Kimmins, from Uganda, the only currently described species. There are also several more undescribed species of this group widespread in Africa.
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A tuple space web service for distributed programming-Simplifying distributed web services applications
- Wells, George C, Mueller, Barbara, Schulé, Lo¨ıc
- Authors: Wells, George C , Mueller, Barbara , Schulé, Lo¨ıc
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430437 , vital:72691 , https://www.scitepress.org/PublishedPapers/2008/15170/15170.pdf
- Description: This paper describes a new tuple space web service for coordination and communication in distributed web applications. This web service is based on the Linda programming model. Linda is a coordination lan-guage for parallel and distributed processing, providing a communica-tion mechanism based on a logically shared memory space. The origi-nal Linda model has been extended through the provision of a pro-grammable mechanism, providing additional flexibility and improved performance. The implementation of the web service is discussed, to-gether with the details of the programmable matching mechanism. Some results from the implementation of a location-based mobile appli-cation, using the tuple space web service are presented, demonstrating the benefits of our system.
- Full Text:
- Authors: Wells, George C , Mueller, Barbara , Schulé, Lo¨ıc
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430437 , vital:72691 , https://www.scitepress.org/PublishedPapers/2008/15170/15170.pdf
- Description: This paper describes a new tuple space web service for coordination and communication in distributed web applications. This web service is based on the Linda programming model. Linda is a coordination lan-guage for parallel and distributed processing, providing a communica-tion mechanism based on a logically shared memory space. The origi-nal Linda model has been extended through the provision of a pro-grammable mechanism, providing additional flexibility and improved performance. The implementation of the web service is discussed, to-gether with the details of the programmable matching mechanism. Some results from the implementation of a location-based mobile appli-cation, using the tuple space web service are presented, demonstrating the benefits of our system.
- Full Text:
A VLBI study of OH masers in a proto-planetary nebula OH 0.9+1.3
- Authors: McAlpine, Kim
- Date: 2008
- Subjects: Very long baseline interferometry , Proto-planetary nebulae , Masers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5499 , http://hdl.handle.net/10962/d1005285 , Very long baseline interferometry , Proto-planetary nebulae , Masers
- Description: This thesis reports the calibration, imaging and analysis of one epoch of VLBA observations of the 1612 MHz OH maser emission from the protoplanetary nebula OH 0.9+1.3. These are the first polarisation VLBI observations of this source and the spatial morphology of the OH emission is resolved on this scale. Proto-planetary nebulae represent the transition phase in the evolution of stars between the asymptotic giant branch (AGB) phase and their emergence as planetary nebulae. A long-standing astronomical question is how the predominantly spherical circumstellar envelopes of AGB stars evolve into the bipolar and axisymmetric structures that are commonly observed in planetary nebula. Proto-planetary nebulae offer a unique opportunity to study this transformation process. The high-resolution VLBI maps produced in this thesis were used to investigate the morphology and kinematics of OH 0.9+1.3 with a view to gaining insight into the development of asymmetries in the circumstellar material. The OH maser emission of OH 0.9+1.3 has a double-peaked profile with one peak blue-shifted and the other red-shifted with respect to the stellar velocity. The total intensity maser maps demonstrate a considerable degree of asymmetry with the blue- and red-shifted emission located in spatially distinct regions of the envelope. The blue-shifted emission is distributed preferentially along an axis at a projected position angle of » 135± ( North through East). The morphology of this source is not consistent with the standard symmetric thin-shell model and an attempt to fit the traditional OH/IR kinematic model of a simple expanding shell to the maser components was found to be unsatisfactory. No definitive evidence of a bipolar outflow was observed either. The high degree of asymmetry observed in the source is consistent with its status as a proto-planetary nebula. The source was imaged in all four Stokes parameters and the fractional linear and circular polarisations of the maser components were derived from the Stokes parameter maps. In all except one of the components the total fractional polarisation was found to be low ( < 15%). The mean fractional linear and circular polarisation were calculated to be 5.54% and 7.11% respectively. The absence of an identifiable Zeeman pair in the Stokes V map prohibited the estimation of the magnetic field in the circumstellar envelope of this source.
- Full Text:
- Authors: McAlpine, Kim
- Date: 2008
- Subjects: Very long baseline interferometry , Proto-planetary nebulae , Masers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5499 , http://hdl.handle.net/10962/d1005285 , Very long baseline interferometry , Proto-planetary nebulae , Masers
- Description: This thesis reports the calibration, imaging and analysis of one epoch of VLBA observations of the 1612 MHz OH maser emission from the protoplanetary nebula OH 0.9+1.3. These are the first polarisation VLBI observations of this source and the spatial morphology of the OH emission is resolved on this scale. Proto-planetary nebulae represent the transition phase in the evolution of stars between the asymptotic giant branch (AGB) phase and their emergence as planetary nebulae. A long-standing astronomical question is how the predominantly spherical circumstellar envelopes of AGB stars evolve into the bipolar and axisymmetric structures that are commonly observed in planetary nebula. Proto-planetary nebulae offer a unique opportunity to study this transformation process. The high-resolution VLBI maps produced in this thesis were used to investigate the morphology and kinematics of OH 0.9+1.3 with a view to gaining insight into the development of asymmetries in the circumstellar material. The OH maser emission of OH 0.9+1.3 has a double-peaked profile with one peak blue-shifted and the other red-shifted with respect to the stellar velocity. The total intensity maser maps demonstrate a considerable degree of asymmetry with the blue- and red-shifted emission located in spatially distinct regions of the envelope. The blue-shifted emission is distributed preferentially along an axis at a projected position angle of » 135± ( North through East). The morphology of this source is not consistent with the standard symmetric thin-shell model and an attempt to fit the traditional OH/IR kinematic model of a simple expanding shell to the maser components was found to be unsatisfactory. No definitive evidence of a bipolar outflow was observed either. The high degree of asymmetry observed in the source is consistent with its status as a proto-planetary nebula. The source was imaged in all four Stokes parameters and the fractional linear and circular polarisations of the maser components were derived from the Stokes parameter maps. In all except one of the components the total fractional polarisation was found to be low ( < 15%). The mean fractional linear and circular polarisation were calculated to be 5.54% and 7.11% respectively. The absence of an identifiable Zeeman pair in the Stokes V map prohibited the estimation of the magnetic field in the circumstellar envelope of this source.
- Full Text:
A xylem retrieval pathway in rice leaf blades – evidence of a role for endocytosis?
- Botha, Christiaan E J, Aoki, N, Scofield, G N, Liu, Lin, Furbank, R T, White, R G
- Authors: Botha, Christiaan E J , Aoki, N , Scofield, G N , Liu, Lin , Furbank, R T , White, R G
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6505 , http://hdl.handle.net/10962/d1005930 , http://dx.doi.org/10.1093/jxb/ern150
- Description: The structure and transport properties of pit membranes at the interface between the metaxylem and xylem parenchyma cells and the possible role of these pit membranes in solute transfer to the phloem was investigated. Electron microscopy revealed a fibrillar, almost tubular matrix within the pit membrane structure between the xylem vessels and xylem parenchyma of leaf blade bundles in rice (Oryza sativa). These pits are involved primarily with regulating water flux to the surrounding xylem parenchyma cells. Vascular parenchyma cells contain large mitochondrial populations, numerous dictyosomes, endomembrane complexes and vesicles in close proximity to the pit membrane. Taken collectively this suggests that endocytosis may occur at this interface. A weak solution of 5,6-carboxyfluorescein diacetate (5,6-CFDA) was applied to cut ends of leaves and after a minimum of 45 minutes, the distribution of the fluorescent cleavage product, 5,6-carboxyfluorescein (5,6-CF) was observed using confocal microscopy. Cleavage of 5,6-CFDA occurred within the xylem parenchyma cells and the non-polar 5,6-CF was then symplasmically transported to other parenchyma elements and ultimately, via numerous pore plasmodesmata, to adjacent thick-walled sieve tubes. Application of Lucifer Yellow, and, separately, Texas Red labelled dextran (10 kDa) to the transpiration stream, confirmed that these membrane-impermeant probes could only have been offloaded from the xylem via the xylem vessel-xylem parenchyma pit membranes, suggesting endocytotic transmembrane transfer of these membrane-impermeant fluorophores. Accumulation within the thick-walled sieve tubes, but not in thin-walled sieve tubes, confirms the presence of a symplasmic phloem loading pathway, via pore plasmodesmata between xylem parenchyma and thick-walled sieve tubes, but not thin-walled sieve tubes.
- Full Text:
- Authors: Botha, Christiaan E J , Aoki, N , Scofield, G N , Liu, Lin , Furbank, R T , White, R G
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6505 , http://hdl.handle.net/10962/d1005930 , http://dx.doi.org/10.1093/jxb/ern150
- Description: The structure and transport properties of pit membranes at the interface between the metaxylem and xylem parenchyma cells and the possible role of these pit membranes in solute transfer to the phloem was investigated. Electron microscopy revealed a fibrillar, almost tubular matrix within the pit membrane structure between the xylem vessels and xylem parenchyma of leaf blade bundles in rice (Oryza sativa). These pits are involved primarily with regulating water flux to the surrounding xylem parenchyma cells. Vascular parenchyma cells contain large mitochondrial populations, numerous dictyosomes, endomembrane complexes and vesicles in close proximity to the pit membrane. Taken collectively this suggests that endocytosis may occur at this interface. A weak solution of 5,6-carboxyfluorescein diacetate (5,6-CFDA) was applied to cut ends of leaves and after a minimum of 45 minutes, the distribution of the fluorescent cleavage product, 5,6-carboxyfluorescein (5,6-CF) was observed using confocal microscopy. Cleavage of 5,6-CFDA occurred within the xylem parenchyma cells and the non-polar 5,6-CF was then symplasmically transported to other parenchyma elements and ultimately, via numerous pore plasmodesmata, to adjacent thick-walled sieve tubes. Application of Lucifer Yellow, and, separately, Texas Red labelled dextran (10 kDa) to the transpiration stream, confirmed that these membrane-impermeant probes could only have been offloaded from the xylem via the xylem vessel-xylem parenchyma pit membranes, suggesting endocytotic transmembrane transfer of these membrane-impermeant fluorophores. Accumulation within the thick-walled sieve tubes, but not in thin-walled sieve tubes, confirms the presence of a symplasmic phloem loading pathway, via pore plasmodesmata between xylem parenchyma and thick-walled sieve tubes, but not thin-walled sieve tubes.
- Full Text:
Access to educational resources: illustrative examples from rural schools in the Eastern Cape Province
- Authors: Hendricks, Monica
- Date: 2008
- Language: English
- Type: Book chapter
- Identifier: vital:7020 , http://hdl.handle.net/10962/d1007200
- Description: [Introduction] This chapter looks at the causes and effects of the widely varying degree of access to material resources across schools in the Eastern Cape. Starting with a broad overview of schools and classroom resources across the whole province, I go on to examine the Grahamstown education district. I discuss the inequalities in resource provision between groupings of schools in the district: comparing independent and state schools, and also examining disparities across schools in different localities within the government sector. The role of parents in providing resources for their children’s schooling is also discussed, as are the relationships among the various participants in education, such as non-governmental organisations, officials of the Department of Education, and teachers.
- Full Text:
- Authors: Hendricks, Monica
- Date: 2008
- Language: English
- Type: Book chapter
- Identifier: vital:7020 , http://hdl.handle.net/10962/d1007200
- Description: [Introduction] This chapter looks at the causes and effects of the widely varying degree of access to material resources across schools in the Eastern Cape. Starting with a broad overview of schools and classroom resources across the whole province, I go on to examine the Grahamstown education district. I discuss the inequalities in resource provision between groupings of schools in the district: comparing independent and state schools, and also examining disparities across schools in different localities within the government sector. The role of parents in providing resources for their children’s schooling is also discussed, as are the relationships among the various participants in education, such as non-governmental organisations, officials of the Department of Education, and teachers.
- Full Text:
Action research on leadership style, and relationships in an East London law firm
- Authors: Stoltz, Tania
- Date: 2008
- Subjects: Action research Law offices Leadership Law firms--South Africa--East London Law offices--South Africa--East London
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:798 , http://hdl.handle.net/10962/d1004592
- Description: "Good leadership springs from a genuine passion for the work and a genuine concern for other people. Great Leaders are people who love what they do and want to share that love with others. " (Daft, 2005:20). During an informal discussion with my husband Hugo Daniels, the leader in this Action Research Case Study, it became apparent that lawyers do not attend a single module or complete a single subject during their formal training at university to obtain their law degree that is related to the field of leadership and how to lead, inspire and motivate followers. The discussion centered on the problems the leader was experiencing in his East London law firm, problems he believed to be as a result of his lack of knowledge in the field of leadership. And so this research project began. It was obvious from the start that to intervene in the firm in order to bring about change would need the participation of everyone in the firm. The first step towards facilitating change would be to change the leadership style of the director of the firm. He would be required to gain knowledge in the field of leadership and the effects that different leadership styles have on followers. At the same time staff's perception of the current leadership style would have to be determined, as well as the desired style for their leader. The research process could then begin, based on the needs expressed by the staff and with participation from all levels in the firm. The case involved 27 members of staff made up of three heads of departments, twenty three general staff members and the leader. Data was gathered through formal interviews with the leader and the heads of departments, as well as from personal journals kept by two heads of departments and the leader. General staff members were first asked to complete The Productive Practice Survey (Hall 1987) to determine their perceptions of the current leadership style in the firm and what they thought they needed from their leader if the firm is to move forward. The Productive Practice Survey (Hall 1987) was not used with the intention of gathering quantitative data, but rather as a means of gathering information of staff's perception in general while ensuring anonymity, so as to facilitate a discussion during a feedback session. The Productive Survey's (Hall 1987) content and working is explained in further detail in Chapter 3 on page 44. Initially participants were skeptical of the process and used the survey as a medium to lash out against the firm and Hugo Daniels as a leader, leaving no room for suggestions for improvement, an "it is what it is" approach. During the feedback session general staff members became more open when they realized that change would benefit them, as changes would be suggested by them and implemented with their participation. They became less reluctant about change and provided valuable input during the session. All participants understood that this Participatory Action Research intervention was only the beginning of change in the firm and the sustainability of the changes rests on the firm as a whole, and working towards it would be a continuous process not ending with the Participatory Action Research process.
- Full Text:
- Authors: Stoltz, Tania
- Date: 2008
- Subjects: Action research Law offices Leadership Law firms--South Africa--East London Law offices--South Africa--East London
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:798 , http://hdl.handle.net/10962/d1004592
- Description: "Good leadership springs from a genuine passion for the work and a genuine concern for other people. Great Leaders are people who love what they do and want to share that love with others. " (Daft, 2005:20). During an informal discussion with my husband Hugo Daniels, the leader in this Action Research Case Study, it became apparent that lawyers do not attend a single module or complete a single subject during their formal training at university to obtain their law degree that is related to the field of leadership and how to lead, inspire and motivate followers. The discussion centered on the problems the leader was experiencing in his East London law firm, problems he believed to be as a result of his lack of knowledge in the field of leadership. And so this research project began. It was obvious from the start that to intervene in the firm in order to bring about change would need the participation of everyone in the firm. The first step towards facilitating change would be to change the leadership style of the director of the firm. He would be required to gain knowledge in the field of leadership and the effects that different leadership styles have on followers. At the same time staff's perception of the current leadership style would have to be determined, as well as the desired style for their leader. The research process could then begin, based on the needs expressed by the staff and with participation from all levels in the firm. The case involved 27 members of staff made up of three heads of departments, twenty three general staff members and the leader. Data was gathered through formal interviews with the leader and the heads of departments, as well as from personal journals kept by two heads of departments and the leader. General staff members were first asked to complete The Productive Practice Survey (Hall 1987) to determine their perceptions of the current leadership style in the firm and what they thought they needed from their leader if the firm is to move forward. The Productive Practice Survey (Hall 1987) was not used with the intention of gathering quantitative data, but rather as a means of gathering information of staff's perception in general while ensuring anonymity, so as to facilitate a discussion during a feedback session. The Productive Survey's (Hall 1987) content and working is explained in further detail in Chapter 3 on page 44. Initially participants were skeptical of the process and used the survey as a medium to lash out against the firm and Hugo Daniels as a leader, leaving no room for suggestions for improvement, an "it is what it is" approach. During the feedback session general staff members became more open when they realized that change would benefit them, as changes would be suggested by them and implemented with their participation. They became less reluctant about change and provided valuable input during the session. All participants understood that this Participatory Action Research intervention was only the beginning of change in the firm and the sustainability of the changes rests on the firm as a whole, and working towards it would be a continuous process not ending with the Participatory Action Research process.
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Adoption of ICTs in a marginalised area of South Africa
- Mapi, Thandeka, Dalvit, Lorenzo, Terzoli, Alfredo
- Authors: Mapi, Thandeka , Dalvit, Lorenzo , Terzoli, Alfredo
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431130 , vital:72747 , https://d1wqtxts1xzle7.cloudfront.net/4390301/5-thandeka-libre.pdf?1390837024=response-content-disposi-tion=inline%3B+filename%3DAdoption_of_ICTs_in_a_Marginalised_Area.pdfExpires=1714988863Signature=N683m3iYa8BDSsrNBb-fZpYmsy~pftZZQbiEdNz8ZFJaL2I-Wt32FIJcLEKFnrSjj0AfnYak4RVZjuZhuFVHQZOnkt7tIBBwccqexeEkwq94rCX6r1~aA~GdyL4Z3WzHRK~Xoug17mnu869TGq8VxuSNBf-LmbSr03uZeXlk2dpobbp3ROl06wauhLm02p1th1qBM5n-Bc0q8wYS-zkY-jA9fc7w6ZE~m6hlHE6Amt1xg~db99oRcu1EuXSdHyWDZDw3OsQ9zlMfX7AU6EBhfAtFbxXuVXOlNOEPuXHgiQ1UbFveqfVKGFRg0dmYXzw62MQM0EQQ2g4qXgk2Xc2z0cQ__Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: This paper examines how a community in Dwesa, a marginalised area in the Transkei Region of the Eastern Cape, South Africa, adopts Information and Communication Technologies (ICTs). This research is part of the Siyakhula project, which aims at promoting the potential of the area through ICTs. The project is situated in four different schools: Mpume, Nondobo, Mtokwane and Ngwane. Fostering ICT awareness and a sense of owner-ship by the community are seen as crucial factors, and computer literacy education is an integral part of the project. The study focuses on how di-verse groups of people adopt new technologies and approach ICT educa-tion. Qualitative research methods such as Participatory Action Research (PAR) and Participant Observation (PO) were adopted in the study.
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- Authors: Mapi, Thandeka , Dalvit, Lorenzo , Terzoli, Alfredo
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431130 , vital:72747 , https://d1wqtxts1xzle7.cloudfront.net/4390301/5-thandeka-libre.pdf?1390837024=response-content-disposi-tion=inline%3B+filename%3DAdoption_of_ICTs_in_a_Marginalised_Area.pdfExpires=1714988863Signature=N683m3iYa8BDSsrNBb-fZpYmsy~pftZZQbiEdNz8ZFJaL2I-Wt32FIJcLEKFnrSjj0AfnYak4RVZjuZhuFVHQZOnkt7tIBBwccqexeEkwq94rCX6r1~aA~GdyL4Z3WzHRK~Xoug17mnu869TGq8VxuSNBf-LmbSr03uZeXlk2dpobbp3ROl06wauhLm02p1th1qBM5n-Bc0q8wYS-zkY-jA9fc7w6ZE~m6hlHE6Amt1xg~db99oRcu1EuXSdHyWDZDw3OsQ9zlMfX7AU6EBhfAtFbxXuVXOlNOEPuXHgiQ1UbFveqfVKGFRg0dmYXzw62MQM0EQQ2g4qXgk2Xc2z0cQ__Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: This paper examines how a community in Dwesa, a marginalised area in the Transkei Region of the Eastern Cape, South Africa, adopts Information and Communication Technologies (ICTs). This research is part of the Siyakhula project, which aims at promoting the potential of the area through ICTs. The project is situated in four different schools: Mpume, Nondobo, Mtokwane and Ngwane. Fostering ICT awareness and a sense of owner-ship by the community are seen as crucial factors, and computer literacy education is an integral part of the project. The study focuses on how di-verse groups of people adopt new technologies and approach ICT educa-tion. Qualitative research methods such as Participatory Action Research (PAR) and Participant Observation (PO) were adopted in the study.
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Adsorption of 4-nitrophenol onto Amberlite® IRA-900 modified with metallophthalocyanines
- Marais, Eloïse A, Nyokong, Tebello
- Authors: Marais, Eloïse A , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268576 , vital:54211 , xlink:href="https://doi.org/10.1016/j.jhazmat.2007.06.096"
- Description: The adsorption of 4-nitrophenol using commercially available Amberlite® IRA-900 modified with metal phthalocyanines (MPc) was investigated. The metallophthalocyanines immobilised onto the surface of Amberlite® IRA-900 include Fe (FePcS4), Co (CoPcS4) and Ni (NiPcS4) tetrasulphophthalocyanines, and differently sulphonated phthalocyanine mixtures of Fe (FePcSmix), Co (CoPcSmix) and Ni (NiPcSmix). Adsorption rates were fastest for the modified adsorbents at a loading of 1 × 10−3 g MPc/g Amberlite, at pH 9. The highest amount of 4-NP removal was obtained on FePcSmix modified Amberlite® IRA-900 with Qt = 42.9 mmol g−1 and adsorption efficiency of 86%. The recovery efficiency of 4-NP within 150 min was 76%. Using the Langmuir–Hinshelwood kinetic model, the complexes showed an order of 4-nitrophenol adsorption to be as follows: CoPcSmix > NiPcS4 > NiPcSmix > FePcS4 > FePcSmix > CoPcS4. The MPc modified Amberlite® IRA-900 was used repeatedly, following removal of 4-NP by nitric acid, without any significant loss of activity.
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- Authors: Marais, Eloïse A , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268576 , vital:54211 , xlink:href="https://doi.org/10.1016/j.jhazmat.2007.06.096"
- Description: The adsorption of 4-nitrophenol using commercially available Amberlite® IRA-900 modified with metal phthalocyanines (MPc) was investigated. The metallophthalocyanines immobilised onto the surface of Amberlite® IRA-900 include Fe (FePcS4), Co (CoPcS4) and Ni (NiPcS4) tetrasulphophthalocyanines, and differently sulphonated phthalocyanine mixtures of Fe (FePcSmix), Co (CoPcSmix) and Ni (NiPcSmix). Adsorption rates were fastest for the modified adsorbents at a loading of 1 × 10−3 g MPc/g Amberlite, at pH 9. The highest amount of 4-NP removal was obtained on FePcSmix modified Amberlite® IRA-900 with Qt = 42.9 mmol g−1 and adsorption efficiency of 86%. The recovery efficiency of 4-NP within 150 min was 76%. Using the Langmuir–Hinshelwood kinetic model, the complexes showed an order of 4-nitrophenol adsorption to be as follows: CoPcSmix > NiPcS4 > NiPcSmix > FePcS4 > FePcSmix > CoPcS4. The MPc modified Amberlite® IRA-900 was used repeatedly, following removal of 4-NP by nitric acid, without any significant loss of activity.
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