Spatio-temporal dynamics of ichthyoplankton in the Kowie estuary, South Africa
- Authors: Kruger, Michelle
- Date: 2010
- Subjects: Fishes -- Larvae -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5319 , http://hdl.handle.net/10962/d1005164 , Fishes -- Larvae -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred
- Description: Ichthyoplankton dynamics in the permanently open Kowie Estuary, in the warm temperate region of South Africa was investigated. The composition, abundance, distribution and seasonality of larval fishes were studied over a two year period between 2004 and 2006. Additionally, tidal exchange of ichthyoplankton and the use of frontal zones in the mouth region of the estuary were also explored between 2008 and 2009. Temporal and spatial trends in occurrence of larval fishes within the estuary and associated marina were obtained from data collected seasonally using boat-based plankton netting at 14 sampling stations along the length of the estuary. A total of 11 128 larval fishes were collected, representing 23 families and 38 taxa. Clupeidae and Gobiidae were the dominant fish families, contributing 47.0 % and 24.7 % respectively to the total catch. Estuarine resident species dominated the overall catch (91 %). A notable absence of older stage larvae and early juveniles characterised the artificial channels of the marina and estuary mouth region. This was attributed to the absence of a shallow, marginal water habitat typical of successful estuarine nursery areas. Tidal exchange of larval fishes was investigated in the Kowie Estuary using a new technique. A set of drifting light traps were set repetitively on the ebb and flood tide every second night for two consecutive 14 day periods during the peak estuarine recruitment period. A total of 553 larval fishes were caught during the study, representing nine families and 26 species. Blenniidae and Clupeidae dominated the catches. Family and species occurrence changed with tide state. Species richness (d) and diversity (H’) varied with tide and was highest on flood tides. Estuary-dependent species, such as Omobranchus woodii were more dominant on flood tides, whilst larvae of marine-spawned species, such as Sardinops sagax, were dominant on the ebb tide. Light trap catches yielded a different composition in terms of development stage / size and species, when compared to towed net studies. Towed plankton nets were again used to study the shear fronts that characterise the mouth region of the canalised Kowie Estuary. It was hypothesised that the convergence zone of the front provides feeding opportunities for ichthyoplankton. Ichthyoplankton, zooplankton and phytoplankton was collected from within and immediately outside of the convergence zone during frontal conditions. Species specific distribution trends emerged from this study. Postflexion larvae and early juvenile stages of the estuary dependent Mugilidae were only present in the foam line of the convergence zones. Some known predators of ichthyoplankton were also present in slightly higher numbers in the convergence zone (isopods) while other predators such as mysid shrimps, chaetognaths and cnidarians were more abundant out of the convergence zone. It appears that these zones may provide access to temporary food patches in the lower estuary but will be accompanied by a trade-off with increased isopod predators. The Kowie Estuary is a heavily impacted system and lack of adequate freshwater supply; artificial channelling and pollution ultimately have a negative impact of the success of this system as a nursery area. Rehabilitation of marginal areas in the lower estuary and marina is suggested as remedial action to re-establish the integrity of the nursery function this system could offer.
- Full Text:
- Date Issued: 2010
- Authors: Kruger, Michelle
- Date: 2010
- Subjects: Fishes -- Larvae -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5319 , http://hdl.handle.net/10962/d1005164 , Fishes -- Larvae -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred
- Description: Ichthyoplankton dynamics in the permanently open Kowie Estuary, in the warm temperate region of South Africa was investigated. The composition, abundance, distribution and seasonality of larval fishes were studied over a two year period between 2004 and 2006. Additionally, tidal exchange of ichthyoplankton and the use of frontal zones in the mouth region of the estuary were also explored between 2008 and 2009. Temporal and spatial trends in occurrence of larval fishes within the estuary and associated marina were obtained from data collected seasonally using boat-based plankton netting at 14 sampling stations along the length of the estuary. A total of 11 128 larval fishes were collected, representing 23 families and 38 taxa. Clupeidae and Gobiidae were the dominant fish families, contributing 47.0 % and 24.7 % respectively to the total catch. Estuarine resident species dominated the overall catch (91 %). A notable absence of older stage larvae and early juveniles characterised the artificial channels of the marina and estuary mouth region. This was attributed to the absence of a shallow, marginal water habitat typical of successful estuarine nursery areas. Tidal exchange of larval fishes was investigated in the Kowie Estuary using a new technique. A set of drifting light traps were set repetitively on the ebb and flood tide every second night for two consecutive 14 day periods during the peak estuarine recruitment period. A total of 553 larval fishes were caught during the study, representing nine families and 26 species. Blenniidae and Clupeidae dominated the catches. Family and species occurrence changed with tide state. Species richness (d) and diversity (H’) varied with tide and was highest on flood tides. Estuary-dependent species, such as Omobranchus woodii were more dominant on flood tides, whilst larvae of marine-spawned species, such as Sardinops sagax, were dominant on the ebb tide. Light trap catches yielded a different composition in terms of development stage / size and species, when compared to towed net studies. Towed plankton nets were again used to study the shear fronts that characterise the mouth region of the canalised Kowie Estuary. It was hypothesised that the convergence zone of the front provides feeding opportunities for ichthyoplankton. Ichthyoplankton, zooplankton and phytoplankton was collected from within and immediately outside of the convergence zone during frontal conditions. Species specific distribution trends emerged from this study. Postflexion larvae and early juvenile stages of the estuary dependent Mugilidae were only present in the foam line of the convergence zones. Some known predators of ichthyoplankton were also present in slightly higher numbers in the convergence zone (isopods) while other predators such as mysid shrimps, chaetognaths and cnidarians were more abundant out of the convergence zone. It appears that these zones may provide access to temporary food patches in the lower estuary but will be accompanied by a trade-off with increased isopod predators. The Kowie Estuary is a heavily impacted system and lack of adequate freshwater supply; artificial channelling and pollution ultimately have a negative impact of the success of this system as a nursery area. Rehabilitation of marginal areas in the lower estuary and marina is suggested as remedial action to re-establish the integrity of the nursery function this system could offer.
- Full Text:
- Date Issued: 2010
Achieving a realistic utopia: Rawls, realization, and the task of political philosophy
- Authors: Terlazzo, Rosa Elizabeth
- Date: 2010
- Subjects: Rawls, John, 1921-2002 Political science -- Philosophy Justice -- Philosophy Utopias -- Philosophy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2721 , http://hdl.handle.net/10962/d1002851
- Description: In this thesis I argue that the tradition of political philosophy which follows in John Rawls's footsteps is obligated to concern itself not only with the realizability, but also with the realization, of justice. Although Rawls himself expresses a commitment only to the former of these, I argue that the roles which he assigns to political philosophy require him to take on the further commitment to realization. This is because these roles are meant to influence not only political philosophers, but the citizens of the wider community as well. The realistically utopian role, which I take to be the central one, requires political philosophy to inspire in that population a hope which I argue that realizability alone cannot provide. Given the deep revisions regarding the political nature of justice as fairness which Rawls made on the basis of realizability concerns, I argue that his theory must in this case be committed to a similar revision. The hope which political philosophy is meant to provide is simply not realizable until the discipline concerns itself centrally with the task of realization.
- Full Text:
- Date Issued: 2010
- Authors: Terlazzo, Rosa Elizabeth
- Date: 2010
- Subjects: Rawls, John, 1921-2002 Political science -- Philosophy Justice -- Philosophy Utopias -- Philosophy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2721 , http://hdl.handle.net/10962/d1002851
- Description: In this thesis I argue that the tradition of political philosophy which follows in John Rawls's footsteps is obligated to concern itself not only with the realizability, but also with the realization, of justice. Although Rawls himself expresses a commitment only to the former of these, I argue that the roles which he assigns to political philosophy require him to take on the further commitment to realization. This is because these roles are meant to influence not only political philosophers, but the citizens of the wider community as well. The realistically utopian role, which I take to be the central one, requires political philosophy to inspire in that population a hope which I argue that realizability alone cannot provide. Given the deep revisions regarding the political nature of justice as fairness which Rawls made on the basis of realizability concerns, I argue that his theory must in this case be committed to a similar revision. The hope which political philosophy is meant to provide is simply not realizable until the discipline concerns itself centrally with the task of realization.
- Full Text:
- Date Issued: 2010
Creating a new underclass : labour flexibility and the temporary employment services industry
- Authors: Van Der Merwe, Christine
- Date: 2010
- Subjects: Temporary employment , Unfair labor practices -- South Africa , Temporary help services , Temporary help services -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3291 , http://hdl.handle.net/10962/d1003079 , Temporary employment , Unfair labor practices -- South Africa , Temporary help services , Temporary help services -- South Africa
- Description: The core of the research focuses on the Temporary Employment Services (TES) Industry and its ability to provide labour flexibility for a number of client firms. The underlying notion that work is changing and becoming more flexible creates an exploratory realm for the concept of non-standard employment. The thesis draws on the conceptual model of the „flexible firm‟ and argues that the rise in non-standard forms of employment, particularly temporary employment within the TES industry, is primarily a result of the demand for labour flexibility. The TES industry that offers „labour on demand‟ is found to be an extremely secretive industry that is diverse in both its structure and services. The thesis reveals that the clients within the triangular employment relationship (TER) are reaping the most benefits especially with regard to escaping their obligations as the employer. The thesis explores human resource practices, unfair labour practices and the extensive loopholes exploited by the TES industry because of poor regulation. Consequently, the industry creates an „underclass‟ that is unprotected, insecure and easily exploitable. Qualitative research techniques were used in the form of semi-structured interviews. The thesis provides insights into the demand and supply of temporary workers in Port Elizabeth and addresses the problems associated with a TER and the TES industry as a whole.
- Full Text:
- Date Issued: 2010
- Authors: Van Der Merwe, Christine
- Date: 2010
- Subjects: Temporary employment , Unfair labor practices -- South Africa , Temporary help services , Temporary help services -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3291 , http://hdl.handle.net/10962/d1003079 , Temporary employment , Unfair labor practices -- South Africa , Temporary help services , Temporary help services -- South Africa
- Description: The core of the research focuses on the Temporary Employment Services (TES) Industry and its ability to provide labour flexibility for a number of client firms. The underlying notion that work is changing and becoming more flexible creates an exploratory realm for the concept of non-standard employment. The thesis draws on the conceptual model of the „flexible firm‟ and argues that the rise in non-standard forms of employment, particularly temporary employment within the TES industry, is primarily a result of the demand for labour flexibility. The TES industry that offers „labour on demand‟ is found to be an extremely secretive industry that is diverse in both its structure and services. The thesis reveals that the clients within the triangular employment relationship (TER) are reaping the most benefits especially with regard to escaping their obligations as the employer. The thesis explores human resource practices, unfair labour practices and the extensive loopholes exploited by the TES industry because of poor regulation. Consequently, the industry creates an „underclass‟ that is unprotected, insecure and easily exploitable. Qualitative research techniques were used in the form of semi-structured interviews. The thesis provides insights into the demand and supply of temporary workers in Port Elizabeth and addresses the problems associated with a TER and the TES industry as a whole.
- Full Text:
- Date Issued: 2010
Challenges in topside ionospheric modelling over South Africa
- Authors: Sibanda, Patrick
- Date: 2010
- Subjects: Ionospheric electron density -- South Africa Neural networks (Computer science) Atmosphere, Upper Ionosphere
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5453 , http://hdl.handle.net/10962/d1005238
- Description: This thesis creates a basic framework and provides the information necessary to create a more accurate description of the topside ionosphere in terms of the altitude variation of the electron density (Ne) over the South African region. The detailed overview of various topside ionospheric modelling techniques, with specific emphasis on their implications for the efforts to model the South African topside, provides a starting point towards achieving the goals. The novelty of the thesis lies in the investigation of the applicabilityof three different techniques to model the South African topside ionosphere: (1) The possibility of using Artificial Neural Network (ANN) techniques for empirical modelling of the topside ionosphere based on the available, however irregularly sampled, topside sounder measurements. The goal of this model was to test the ability of ANN techniques to capture the complex relationships between the various ionospheric variables using irregularly distributed measurements. While this technique is promising, the method did not show significant improvement over the International Reference Ionosphere (IRI) model results when compared with the actual measurements. (2) Application of the diffusive equilibrium theory. Although based on sound physics foundations, the method only operates on a generalised level leading to results that are not necessarily unique. Furthermore, the approach relies on many ionospheric variables as inputs which are derived from other models whose accuracy is not verified. (3) Attempts to complement the standard functional techniques, (Chapman, Epstein, Exponential and Parabolic), with Global Positioning System (GPS) and ionosonde measurements in an effort to provide deeper insights into the actual conditions within the ionosphere. The vertical Ne distribution is reconstructed by linking together the different aspects of the constituent ions and their transition height by considering how they influence the shape of the profile. While this approach has not been tested against actual measurements, results show that the method could be potentially useful for topside ionospheric studies. Due to the limitations of each technique reviewed, this thesis observes that the employment of an approach that incorporates both theoretical onsiderations and empirical aspects has the potential to lead to a more accurate characterisation of the topside ionospheric behaviour, and resulting in improved models in terms of reliability and forecasting ability. The point is made that a topside sounder mission for South Africa would provide the required measured topside ionospheric data and answer the many science questions that this region poses as well as solving a number of the limitations set out in this thesis.
- Full Text:
- Date Issued: 2010
- Authors: Sibanda, Patrick
- Date: 2010
- Subjects: Ionospheric electron density -- South Africa Neural networks (Computer science) Atmosphere, Upper Ionosphere
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5453 , http://hdl.handle.net/10962/d1005238
- Description: This thesis creates a basic framework and provides the information necessary to create a more accurate description of the topside ionosphere in terms of the altitude variation of the electron density (Ne) over the South African region. The detailed overview of various topside ionospheric modelling techniques, with specific emphasis on their implications for the efforts to model the South African topside, provides a starting point towards achieving the goals. The novelty of the thesis lies in the investigation of the applicabilityof three different techniques to model the South African topside ionosphere: (1) The possibility of using Artificial Neural Network (ANN) techniques for empirical modelling of the topside ionosphere based on the available, however irregularly sampled, topside sounder measurements. The goal of this model was to test the ability of ANN techniques to capture the complex relationships between the various ionospheric variables using irregularly distributed measurements. While this technique is promising, the method did not show significant improvement over the International Reference Ionosphere (IRI) model results when compared with the actual measurements. (2) Application of the diffusive equilibrium theory. Although based on sound physics foundations, the method only operates on a generalised level leading to results that are not necessarily unique. Furthermore, the approach relies on many ionospheric variables as inputs which are derived from other models whose accuracy is not verified. (3) Attempts to complement the standard functional techniques, (Chapman, Epstein, Exponential and Parabolic), with Global Positioning System (GPS) and ionosonde measurements in an effort to provide deeper insights into the actual conditions within the ionosphere. The vertical Ne distribution is reconstructed by linking together the different aspects of the constituent ions and their transition height by considering how they influence the shape of the profile. While this approach has not been tested against actual measurements, results show that the method could be potentially useful for topside ionospheric studies. Due to the limitations of each technique reviewed, this thesis observes that the employment of an approach that incorporates both theoretical onsiderations and empirical aspects has the potential to lead to a more accurate characterisation of the topside ionospheric behaviour, and resulting in improved models in terms of reliability and forecasting ability. The point is made that a topside sounder mission for South Africa would provide the required measured topside ionospheric data and answer the many science questions that this region poses as well as solving a number of the limitations set out in this thesis.
- Full Text:
- Date Issued: 2010
Photophysical studies of zinc and indium tetraaminophthalocyanines in the presence of CdTe quantum dots
- Authors: Britton, Jonathan
- Date: 2010
- Subjects: Indium , Zinc , Quantum dots , Phthalocyanines , Photochemotherapy , Nonlinear optics , Nanocrystals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4332 , http://hdl.handle.net/10962/d1004993 , Indium , Zinc , Quantum dots , Phthalocyanines , Photochemotherapy , Nonlinear optics , Nanocrystals
- Description: CdTe QDs capped with mercaptopropionic acid (MPA) and thioglycolic acid (TGA) were covalently linked to zinc and indium tetraaminophthalocyanines (TAPcs) using N-ethyl-N(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) as the coupling agents. The results presented give evidence in favour of formation of an amide bond between the MTAPc and CdTe QDs. Both the linked ZnTAPc–QD complexes and the mixture of QDs and ZnTAPc (without chemical linking) showed Förster resonance energy transfer (FRET), though the linked showed less FRET, whereas the QD interactions with InTAPc yielded no evidence of FRET. Both MTAPcs quenched the QDs emission, with quenching constants of the order of 103–104M−1, binding constants of the order of 108-1010M-1 and the number of binding sites for the MTAPc upon the QD being 2. High energy transfer efficiencies were obtained (in some cases as high as 93%), due to the low donor to acceptor distances. Lastly, both MTAPc were shown to be poor optical limiters because their imaginary third-order susceptibility (Im[χ(3)]) was of the order of 10-17-10-16 (optimal range is 10-9-10-11), the hyperpolarizability (γ) of the order of 10-37-10-36 (optimal range is 10-29-10-34) and the k values were above one but below ten.
- Full Text:
- Date Issued: 2010
- Authors: Britton, Jonathan
- Date: 2010
- Subjects: Indium , Zinc , Quantum dots , Phthalocyanines , Photochemotherapy , Nonlinear optics , Nanocrystals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4332 , http://hdl.handle.net/10962/d1004993 , Indium , Zinc , Quantum dots , Phthalocyanines , Photochemotherapy , Nonlinear optics , Nanocrystals
- Description: CdTe QDs capped with mercaptopropionic acid (MPA) and thioglycolic acid (TGA) were covalently linked to zinc and indium tetraaminophthalocyanines (TAPcs) using N-ethyl-N(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) as the coupling agents. The results presented give evidence in favour of formation of an amide bond between the MTAPc and CdTe QDs. Both the linked ZnTAPc–QD complexes and the mixture of QDs and ZnTAPc (without chemical linking) showed Förster resonance energy transfer (FRET), though the linked showed less FRET, whereas the QD interactions with InTAPc yielded no evidence of FRET. Both MTAPcs quenched the QDs emission, with quenching constants of the order of 103–104M−1, binding constants of the order of 108-1010M-1 and the number of binding sites for the MTAPc upon the QD being 2. High energy transfer efficiencies were obtained (in some cases as high as 93%), due to the low donor to acceptor distances. Lastly, both MTAPc were shown to be poor optical limiters because their imaginary third-order susceptibility (Im[χ(3)]) was of the order of 10-17-10-16 (optimal range is 10-9-10-11), the hyperpolarizability (γ) of the order of 10-37-10-36 (optimal range is 10-29-10-34) and the k values were above one but below ten.
- Full Text:
- Date Issued: 2010
Application of multiserver queueing to call centres
- Authors: Majakwara, Jacob
- Date: 2010
- Subjects: Call centers , ERLANG (Computer program language) , Queuing theory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5578 , http://hdl.handle.net/10962/d1015461
- Description: The simplest and most widely used queueing model in call centres is the M/M/k system, sometimes referred to as Erlang-C. For many applications the model is an over-simplification. Erlang-C model ignores among other things busy signals, customer impatience and services that span multiple visits. Although the Erlang-C formula is easily implemented, it is not easy to obtain insight from its answers (for example, to find an approximate answer to questions such as "how many additional agents do I need if the arrival rate doubles?"). An approximation of the Erlang-C formula that gives structural insight into this type of question would be of use to better understand economies of scale in call centre operations. Erlang-C based predictions can also turn out highly inaccurate because of violations of underlying assumptions and these violations are not straightforward to model. For example, non-exponential service times lead one to the M/G/k queue which, in stark contrast to the M/M/k system, is difficult to analyse. This thesis deals mainly with the general M/GI/k model with abandonment. The arrival process conforms to a Poisson process, service durations are independent and identically distributed with a general distribution, there are k servers, and independent and identically distributed customer abandoning times with a general distribution. This thesis will endeavour to analyse call centres using M/GI/k model with abandonment and the data to be used will be simulated using EZSIM-software. The paper by Brown et al. [3] entitled "Statistical Analysis of a Telephone Call Centre: A Queueing-Science Perspective," will be the basis upon which this thesis is built.
- Full Text:
- Date Issued: 2010
- Authors: Majakwara, Jacob
- Date: 2010
- Subjects: Call centers , ERLANG (Computer program language) , Queuing theory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5578 , http://hdl.handle.net/10962/d1015461
- Description: The simplest and most widely used queueing model in call centres is the M/M/k system, sometimes referred to as Erlang-C. For many applications the model is an over-simplification. Erlang-C model ignores among other things busy signals, customer impatience and services that span multiple visits. Although the Erlang-C formula is easily implemented, it is not easy to obtain insight from its answers (for example, to find an approximate answer to questions such as "how many additional agents do I need if the arrival rate doubles?"). An approximation of the Erlang-C formula that gives structural insight into this type of question would be of use to better understand economies of scale in call centre operations. Erlang-C based predictions can also turn out highly inaccurate because of violations of underlying assumptions and these violations are not straightforward to model. For example, non-exponential service times lead one to the M/G/k queue which, in stark contrast to the M/M/k system, is difficult to analyse. This thesis deals mainly with the general M/GI/k model with abandonment. The arrival process conforms to a Poisson process, service durations are independent and identically distributed with a general distribution, there are k servers, and independent and identically distributed customer abandoning times with a general distribution. This thesis will endeavour to analyse call centres using M/GI/k model with abandonment and the data to be used will be simulated using EZSIM-software. The paper by Brown et al. [3] entitled "Statistical Analysis of a Telephone Call Centre: A Queueing-Science Perspective," will be the basis upon which this thesis is built.
- Full Text:
- Date Issued: 2010
The integration of natural resource management into the curriculum of rural under-resourced schools : a Bernsteinian analysis
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2010
- Subjects: Conservation of natural resources -- Study and teaching -- South Africa Environmental education -- Curricula -- South Africa -- Eastern Cape Bernstein, Basil B Nature conservation -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4762 , http://hdl.handle.net/10962/d1007157
- Description: This study was motivated by the need to improve curriculum relevance in poor rural schools through contextualised teaching and learning based on the management of local natural resources. It involved four schools which are located in the Ngqunshwa Local Municipality of the Eastern Cape Province of South Africa. The study's aim was to provide insight into and better understanding of the curriculum implementation process regarding natural resource management (NRM) education in a poor rural education context. This was done by analysing the extent of NRM integration in pedagogic texts, activities and practices in the different fields which constitute the structure of the pedagogic system in this education sector. The study adopted an interpretivist approach to the analysis, which was based on indicators of the extent of NRM integration, and was informed by Bernstein's concepts of classification and curriculum recontextualisation, and his model of the structure of the pedagogic system. The items which were analysed included national and provincial Grade 10 Life Sciences curriculum documents, Grade 10 Life Sciences textbooks, in-service training workshops for Life Sciences teachers, and various school documents, activities and practices. The analysis also involved interviews with educators, and classroom observations of Grade 10 Life Sciences lessons. The results revealed a very high overall level of NRM integration in the Grade 10 Life Sciences curriculum documents produced at national and provincial levels. The overall level of NRM integration was also found to be very high in the Grade 10 Life Science textbooks that were analysed, but very low in the in-service teacher training workshops, and in the schools' documents, activities and practices, especially in the Grade 10 Life Sciences lessons, and in schools' end-of-year Grade 10 Life Sciences examination papers. The study makes a number of recommendations towards effective integration of NRM into the curriculum of Eastern Cape's rural poor schools which include more specific and explicit reference to NRM in the official Grade 10 Life Sciences curriculum documents, the provision of environmental education courses to district education staff and Grade 10 Life Sciences teachers, the training of teachers in the classroom use of textbooks and other educational materials, and regular monitoring of teachers' work. The study also exposes important knowledge gaps which need urgent research attention in order to enhance NRM education in the poor rural schools of the Eastern Cape. These include analysing power and control relationships between the various agencies and agents that are involved with curriculum implementation in this education sector, and conducting investigation into the creation of specialist NRM knowledge and into the quality of NRM knowledge that is transmitted as pedagogic discourse in schools. This study contributes to the fields of rural education and environmental education in South Africa, and to the growing interest in the study of curriculum from a sociology of education perspective in the context of the country’s post-apartheid curriculum reforms.
- Full Text:
- Date Issued: 2010
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2010
- Subjects: Conservation of natural resources -- Study and teaching -- South Africa Environmental education -- Curricula -- South Africa -- Eastern Cape Bernstein, Basil B Nature conservation -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4762 , http://hdl.handle.net/10962/d1007157
- Description: This study was motivated by the need to improve curriculum relevance in poor rural schools through contextualised teaching and learning based on the management of local natural resources. It involved four schools which are located in the Ngqunshwa Local Municipality of the Eastern Cape Province of South Africa. The study's aim was to provide insight into and better understanding of the curriculum implementation process regarding natural resource management (NRM) education in a poor rural education context. This was done by analysing the extent of NRM integration in pedagogic texts, activities and practices in the different fields which constitute the structure of the pedagogic system in this education sector. The study adopted an interpretivist approach to the analysis, which was based on indicators of the extent of NRM integration, and was informed by Bernstein's concepts of classification and curriculum recontextualisation, and his model of the structure of the pedagogic system. The items which were analysed included national and provincial Grade 10 Life Sciences curriculum documents, Grade 10 Life Sciences textbooks, in-service training workshops for Life Sciences teachers, and various school documents, activities and practices. The analysis also involved interviews with educators, and classroom observations of Grade 10 Life Sciences lessons. The results revealed a very high overall level of NRM integration in the Grade 10 Life Sciences curriculum documents produced at national and provincial levels. The overall level of NRM integration was also found to be very high in the Grade 10 Life Science textbooks that were analysed, but very low in the in-service teacher training workshops, and in the schools' documents, activities and practices, especially in the Grade 10 Life Sciences lessons, and in schools' end-of-year Grade 10 Life Sciences examination papers. The study makes a number of recommendations towards effective integration of NRM into the curriculum of Eastern Cape's rural poor schools which include more specific and explicit reference to NRM in the official Grade 10 Life Sciences curriculum documents, the provision of environmental education courses to district education staff and Grade 10 Life Sciences teachers, the training of teachers in the classroom use of textbooks and other educational materials, and regular monitoring of teachers' work. The study also exposes important knowledge gaps which need urgent research attention in order to enhance NRM education in the poor rural schools of the Eastern Cape. These include analysing power and control relationships between the various agencies and agents that are involved with curriculum implementation in this education sector, and conducting investigation into the creation of specialist NRM knowledge and into the quality of NRM knowledge that is transmitted as pedagogic discourse in schools. This study contributes to the fields of rural education and environmental education in South Africa, and to the growing interest in the study of curriculum from a sociology of education perspective in the context of the country’s post-apartheid curriculum reforms.
- Full Text:
- Date Issued: 2010
The taxonomy, life-history and population dynamics of blacktail, Diplodus Capensis (Perciformes: Sparidae), in southern Angola
- Authors: Richardson, Timothy John
- Date: 2010
- Subjects: Diplodus -- Angola , Perciformes -- Angola , Sparidae -- Angola , Fish populations -- Angola , Fishes -- Classification -- Angola , Fisheries -- Angola
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5324 , http://hdl.handle.net/10962/d1005170 , Diplodus -- Angola , Perciformes -- Angola , Sparidae -- Angola , Fish populations -- Angola , Fishes -- Classification -- Angola , Fisheries -- Angola
- Description: The blacktail, Diplodus capensis, is an inshore sparid fish distributed from Mozambique to Angola. This species forms an important component of coastal fisheries within its distribution, one being the subsistence handline fishery in southern Angola. With this fishery being critically important to the livelihoods of local communities, a biological study and stock assessment was conducted to provide information for the management of this species in southern Angola. However, with molecular evidence suggesting that the Benguela current may have separated the southern African populations of many inshore fish species over two million years ago, a morphological, taxonomic analysis was considered necessary to first investigate whether there was evidence for allopatry in this species. A total of 46 morphometric measurements and 18 counts were carried out on specimens collected from various locations in southern Angola and South Africa. Results were analysed using multi-dimensional scaling (MDS) and the significance of clusters was tested using analysis of similarities (ANOSIM). Biological samples of D. capensis were collected monthly from an unexploited area from April 2008 to March 2009. Additional biological samples were collected from the subsistence fishers in an exploited area during May, June and December 2009. Standard biological laboratory techniques were employed for the lifehistory comparison between the exploited and unexploited area. A per-recruit analysis was conducted using the life-history parameters from both areas in order to assess the current status of the subsistence fishery and to investigate the potential short-falls of the per-recruit assessment approach. The morphometric comparison showed that there was not sufficient evidence for speciation between the southern Angolan and South African populations of D. capensis. There was, however, sufficient morphological evidence to suggest that these populations are separate stocks. This indicated that the existing reference points on which the management of the South African population is based are unsuitable for the Angolan population. Diplodus capensis in southern Angola is omnivorous, feeding predominantly on algae, barnacles and mussels. An ontogenetic shift from algae to barnacles and mussels was correlated with allometric growth patterns in their feeding apparatus. This species is a rudimentary hermaphrodite in southern Angola with peak spawning in June and July. The overall sex ratio (M: F) was 1: 4.7 in the unexploited area and 50% maturity was attained at 149.5mm FL and five years. Diplodus capensis in southern Angola exhibits very slow growth with the maximum age observed being 31 years (validated using mark recapture of chemically injected fish). Females [L(t) = 419.5(1-e⁻°·°⁴⁵⁽t⁻³·⁴ ⁾)] grew significantly faster (LRT, p < 0.05) than males [L(t) = 297.4(1-e⁻°·°⁷⁷⁽t⁻²·⁷⁾)], and females dominated the larger size classes and older age classes. In the exploited area, the length and age frequencies were severely truncated, the maximum observed age was greatly reduced (17 years) and the sex ratio was less female biased at 1: 2.2. Although there was no evidence for a physiological response to exploitation through alterations in growth or size/age at sexual maturity between the two areas, there was an increase in the proportion of small females in the exploited area, which may have been a compensatory response for the loss of large females. A combination of an underestimate of longevity, different estimates of the Von Bertalanffy growth parameters and overestimates of the natural mortality rate in the exploited population resulted in a 92% underestimate of the pristine spawner biomass-per-recruit (SBR) value. An assessment based on the actual pristine SBR estimate from the unexploited area revealed that the subsistence fishery had actually reduced D. capensis to 20% of its pristine SBR levels and highlighted the value of pre-exploitation life-history information for the application of per-recruit models. This study has shown that D. capensis in southern Angola displays life-history characteristics that render it susceptible to overexploitation, even at low levels of fishing pressure. The current lack of infrastructure and enforcement capacity in the fisheries department of Angola renders traditional linefish regulatory tools, such as size limits, bag limits and closed seasons, inappropriate. Therefore, suitably designed marine protected areas are recommended as the best management option for this species.
- Full Text:
- Date Issued: 2010
- Authors: Richardson, Timothy John
- Date: 2010
- Subjects: Diplodus -- Angola , Perciformes -- Angola , Sparidae -- Angola , Fish populations -- Angola , Fishes -- Classification -- Angola , Fisheries -- Angola
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5324 , http://hdl.handle.net/10962/d1005170 , Diplodus -- Angola , Perciformes -- Angola , Sparidae -- Angola , Fish populations -- Angola , Fishes -- Classification -- Angola , Fisheries -- Angola
- Description: The blacktail, Diplodus capensis, is an inshore sparid fish distributed from Mozambique to Angola. This species forms an important component of coastal fisheries within its distribution, one being the subsistence handline fishery in southern Angola. With this fishery being critically important to the livelihoods of local communities, a biological study and stock assessment was conducted to provide information for the management of this species in southern Angola. However, with molecular evidence suggesting that the Benguela current may have separated the southern African populations of many inshore fish species over two million years ago, a morphological, taxonomic analysis was considered necessary to first investigate whether there was evidence for allopatry in this species. A total of 46 morphometric measurements and 18 counts were carried out on specimens collected from various locations in southern Angola and South Africa. Results were analysed using multi-dimensional scaling (MDS) and the significance of clusters was tested using analysis of similarities (ANOSIM). Biological samples of D. capensis were collected monthly from an unexploited area from April 2008 to March 2009. Additional biological samples were collected from the subsistence fishers in an exploited area during May, June and December 2009. Standard biological laboratory techniques were employed for the lifehistory comparison between the exploited and unexploited area. A per-recruit analysis was conducted using the life-history parameters from both areas in order to assess the current status of the subsistence fishery and to investigate the potential short-falls of the per-recruit assessment approach. The morphometric comparison showed that there was not sufficient evidence for speciation between the southern Angolan and South African populations of D. capensis. There was, however, sufficient morphological evidence to suggest that these populations are separate stocks. This indicated that the existing reference points on which the management of the South African population is based are unsuitable for the Angolan population. Diplodus capensis in southern Angola is omnivorous, feeding predominantly on algae, barnacles and mussels. An ontogenetic shift from algae to barnacles and mussels was correlated with allometric growth patterns in their feeding apparatus. This species is a rudimentary hermaphrodite in southern Angola with peak spawning in June and July. The overall sex ratio (M: F) was 1: 4.7 in the unexploited area and 50% maturity was attained at 149.5mm FL and five years. Diplodus capensis in southern Angola exhibits very slow growth with the maximum age observed being 31 years (validated using mark recapture of chemically injected fish). Females [L(t) = 419.5(1-e⁻°·°⁴⁵⁽t⁻³·⁴ ⁾)] grew significantly faster (LRT, p < 0.05) than males [L(t) = 297.4(1-e⁻°·°⁷⁷⁽t⁻²·⁷⁾)], and females dominated the larger size classes and older age classes. In the exploited area, the length and age frequencies were severely truncated, the maximum observed age was greatly reduced (17 years) and the sex ratio was less female biased at 1: 2.2. Although there was no evidence for a physiological response to exploitation through alterations in growth or size/age at sexual maturity between the two areas, there was an increase in the proportion of small females in the exploited area, which may have been a compensatory response for the loss of large females. A combination of an underestimate of longevity, different estimates of the Von Bertalanffy growth parameters and overestimates of the natural mortality rate in the exploited population resulted in a 92% underestimate of the pristine spawner biomass-per-recruit (SBR) value. An assessment based on the actual pristine SBR estimate from the unexploited area revealed that the subsistence fishery had actually reduced D. capensis to 20% of its pristine SBR levels and highlighted the value of pre-exploitation life-history information for the application of per-recruit models. This study has shown that D. capensis in southern Angola displays life-history characteristics that render it susceptible to overexploitation, even at low levels of fishing pressure. The current lack of infrastructure and enforcement capacity in the fisheries department of Angola renders traditional linefish regulatory tools, such as size limits, bag limits and closed seasons, inappropriate. Therefore, suitably designed marine protected areas are recommended as the best management option for this species.
- Full Text:
- Date Issued: 2010
The biotechnology of hard coal utilization as a bioprocess substrate
- Mutambanengwe, Cecil Clifford Zvandada
- Authors: Mutambanengwe, Cecil Clifford Zvandada
- Date: 2010
- Subjects: Coal -- Biotechnology Acid mine drainage Coal mines and mining -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3934 , http://hdl.handle.net/10962/d1003993
- Description: The development of coal biotechnology, using hard coal as a substrate, has been impeded by its low reactivity in biological processes. As a result, the more successful application studies have focused on lignitic soft coals. However, new studies have reported using biologically or geologically oxidized hard coal as a functional substrate option for bioprocess applications on a large scale. This study undertook a preliminary investigation into the feasibility of environmental applications of coal biotechnology using oxidized hard coal substrates in both anaerobic and aerobic processes with carbon dioxide, sulfate and oxygen as terminal electron acceptors. A preliminary characterization of the oxidized hard coal substrates was undertaken to determine and predict their viability and behavior as electron donors and carbon sources for environmental bioprocess applications of direct interest to the coal mining industry. Both biologically and geologically oxidized coal substrates showed loss of up to 17% and 52% carbon respectively and incorporation of oxygen ranging from 0.9 – 24%. The latter substrate showed greater loss of carbon and increased oxygenation. The biologically and geologically oxidized hard coal substrates were shown to partition readily into 23% and 32% organic humic acid, a 0.1% fulvic acid fraction and 65% and 59% inorganic and humin fractions respectively. These organic components were shown to be potentially available for biological consumption. In the unmodified hard coal substrate, partitioning was not observed and it did not perform as a functional substrate for any of the bioprocesses investigated. Where carbon dioxide was used as a terminal electron acceptor, methane production ranging from 9 – 26 mg CH4.g substrate-1 was demonstrated from both oxidized coal substrates. Geologically oxidized coal produced 30% more methane than biologically oxidized coal. Methane yields from the geologically oxidized coal in the presence and absence of a co-substrate were 5 – 13-fold higher than previous studies that used hard coal for methanogenesis. Based on these results, and that the development and optimization of the biological oxidation process is currently ongoing, further applications investigated in this study were undertaken using geologically oxidized coal. It was shown using pyrolysis gas chromatography mass spectrometry that the methanogenic system was dependent on the presence of an effective co-substrate supporting the breakdown of the complex organic structures within the oxidized hard coal substrate. Also that the accumulation of aromatic intermediate breakdown compounds predominantly including toluene, furfural, styrene and 2-methoxy vinyl phenol appeared to become inhibitory to both methanogenic and sulfidogenic reactions. This was shown to be a more likely cause of reactor failure rather than substrate exhaustion over time. Evidence of a reductive degradation pathway of the complex organic structures within the oxidized hard coal substrates was shown through the production, accumulation and utilization of volatile fatty acids including acetic, formic, propionic, butyric and valeric acids. Comparative analysis of the volatile fatty acids produced in this system showed that geologically oxidized coal produced 20% more of the volatile fatty acids profiled and double the total concentration compared to the biologically oxidized coal. The use of geologically oxidized hard coal as a functional substrate for biological sulfate reduction was demonstrated in the neutralization of a simulated acid mine drainage wastewater in both batch and continuous process operations. Results showed an increase in pH from pH 4.0 to ~ pH 8.0 with sulfide production rates of ~ 86 mgL-1.day-1 in the batch reactions, while the pH increased to pH 9.0 and sulfide production rates of up to 450 mgL-1.day-1 were measured in the continuous process studies using sand and coal up-flow packed bed reactors. Again, the requirement for an effective co-substrate was demonstrated with lactate shown to function as a true co-substrate in this system. However, a low cost alternative to lactate would need to emerge if the process was to function in large-scale commercial environmental treatment applications. In this regard, the aerobic growth and production of Neosartorya fischeri biomass (0.64 g.biomass.g SOC-1) was demonstrated using oxidized hard coal and glutamate as a co-substrate. Both can be produced from wastes generated on coal mines, with the fungal biomass generated in potentially large volumes. Preliminary demonstration of the use of the fungal biomass as a carbon and electron donor source for biological sulfate reduction was shown and thus that this could serve as an effective substrate for anaerobic environmental treatment processes. Based on these findings, an Integrated Coal Bioprocess model was proposed using oxidized hard coal as a substrate for environmental remediation applications on coal mines. In this approach, potential applications included methane recovery from waste coal, use of waste coal in the treatment of acid mine drainage waste waters and the recovery and use of humic acids in the rehabilitation of open cast mining soils. This study provided a first report demonstrating the use of biologically and geologically oxidized hard coals as bioprocess substrates in environmental bioremediation applications. It also provided an indication that follow-up bioengineering studies to investigate scaled-up applications of these findings would be warranted.
- Full Text:
- Date Issued: 2010
- Authors: Mutambanengwe, Cecil Clifford Zvandada
- Date: 2010
- Subjects: Coal -- Biotechnology Acid mine drainage Coal mines and mining -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3934 , http://hdl.handle.net/10962/d1003993
- Description: The development of coal biotechnology, using hard coal as a substrate, has been impeded by its low reactivity in biological processes. As a result, the more successful application studies have focused on lignitic soft coals. However, new studies have reported using biologically or geologically oxidized hard coal as a functional substrate option for bioprocess applications on a large scale. This study undertook a preliminary investigation into the feasibility of environmental applications of coal biotechnology using oxidized hard coal substrates in both anaerobic and aerobic processes with carbon dioxide, sulfate and oxygen as terminal electron acceptors. A preliminary characterization of the oxidized hard coal substrates was undertaken to determine and predict their viability and behavior as electron donors and carbon sources for environmental bioprocess applications of direct interest to the coal mining industry. Both biologically and geologically oxidized coal substrates showed loss of up to 17% and 52% carbon respectively and incorporation of oxygen ranging from 0.9 – 24%. The latter substrate showed greater loss of carbon and increased oxygenation. The biologically and geologically oxidized hard coal substrates were shown to partition readily into 23% and 32% organic humic acid, a 0.1% fulvic acid fraction and 65% and 59% inorganic and humin fractions respectively. These organic components were shown to be potentially available for biological consumption. In the unmodified hard coal substrate, partitioning was not observed and it did not perform as a functional substrate for any of the bioprocesses investigated. Where carbon dioxide was used as a terminal electron acceptor, methane production ranging from 9 – 26 mg CH4.g substrate-1 was demonstrated from both oxidized coal substrates. Geologically oxidized coal produced 30% more methane than biologically oxidized coal. Methane yields from the geologically oxidized coal in the presence and absence of a co-substrate were 5 – 13-fold higher than previous studies that used hard coal for methanogenesis. Based on these results, and that the development and optimization of the biological oxidation process is currently ongoing, further applications investigated in this study were undertaken using geologically oxidized coal. It was shown using pyrolysis gas chromatography mass spectrometry that the methanogenic system was dependent on the presence of an effective co-substrate supporting the breakdown of the complex organic structures within the oxidized hard coal substrate. Also that the accumulation of aromatic intermediate breakdown compounds predominantly including toluene, furfural, styrene and 2-methoxy vinyl phenol appeared to become inhibitory to both methanogenic and sulfidogenic reactions. This was shown to be a more likely cause of reactor failure rather than substrate exhaustion over time. Evidence of a reductive degradation pathway of the complex organic structures within the oxidized hard coal substrates was shown through the production, accumulation and utilization of volatile fatty acids including acetic, formic, propionic, butyric and valeric acids. Comparative analysis of the volatile fatty acids produced in this system showed that geologically oxidized coal produced 20% more of the volatile fatty acids profiled and double the total concentration compared to the biologically oxidized coal. The use of geologically oxidized hard coal as a functional substrate for biological sulfate reduction was demonstrated in the neutralization of a simulated acid mine drainage wastewater in both batch and continuous process operations. Results showed an increase in pH from pH 4.0 to ~ pH 8.0 with sulfide production rates of ~ 86 mgL-1.day-1 in the batch reactions, while the pH increased to pH 9.0 and sulfide production rates of up to 450 mgL-1.day-1 were measured in the continuous process studies using sand and coal up-flow packed bed reactors. Again, the requirement for an effective co-substrate was demonstrated with lactate shown to function as a true co-substrate in this system. However, a low cost alternative to lactate would need to emerge if the process was to function in large-scale commercial environmental treatment applications. In this regard, the aerobic growth and production of Neosartorya fischeri biomass (0.64 g.biomass.g SOC-1) was demonstrated using oxidized hard coal and glutamate as a co-substrate. Both can be produced from wastes generated on coal mines, with the fungal biomass generated in potentially large volumes. Preliminary demonstration of the use of the fungal biomass as a carbon and electron donor source for biological sulfate reduction was shown and thus that this could serve as an effective substrate for anaerobic environmental treatment processes. Based on these findings, an Integrated Coal Bioprocess model was proposed using oxidized hard coal as a substrate for environmental remediation applications on coal mines. In this approach, potential applications included methane recovery from waste coal, use of waste coal in the treatment of acid mine drainage waste waters and the recovery and use of humic acids in the rehabilitation of open cast mining soils. This study provided a first report demonstrating the use of biologically and geologically oxidized hard coals as bioprocess substrates in environmental bioremediation applications. It also provided an indication that follow-up bioengineering studies to investigate scaled-up applications of these findings would be warranted.
- Full Text:
- Date Issued: 2010
The characterisation of trypanosomal type 1 DnaJ-like proteins
- Authors: Ludewig, Michael Hans
- Date: 2010
- Subjects: Molecular genetics , Molecular chaperones , Protozoa , Heat shock proteins , Trypanosoma
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4126 , http://hdl.handle.net/10962/d1015205
- Description: Trypanosomes are protozoans, of which many are parasitic, and possess complex lifecycles which alternate between mammalian and arthropod hosts. As is the case with most organisms, molecular chaperones and heat shock proteins are encoded within the genomes of these protozoans. These proteins are an integral part of maintaining the structural integrity of proteins during normal and stress conditions. Heat shock protein 40 (Hsp40) is a co-chaperone of heat shock protein 70 (Hsp70) and in some cases can act as a chaperone. These proteins work together to bind non-native polypeptide structures to prevent unfolded protein aggregrate formation in times of stress, translocate proteins across organelle membranes, and transport unsalvageable proteins to proteolytic degradation by the cellular proteasome. Hsp40s are divided into four types based on their domain structure. Analysis of the nuclear genomes of eight trypanosomatid species revealed that less than 10 of the approximate 70 Hsp40 sequences per genome were Type 1 Hsp40s, many of which contained putative orthologues in the other seven trypanosomatid genomes. One of these Type 1 Hsp40s from T b. brucei, Trypanosoma brucei DnaJ 2 (Tbj2), was functionally characterised in T brucei brucei. RNA interference knockdown of expression in T brucei brucei showed that cells deficient in Tbj2 displayed a severe inhibition of the growth of the cell population. The levels of the Tbj2 protein population in T brucei brucei cells increases after exposure to 42°c and the protein was found to have a generalized cytoplasmic subcellular localization at 37°c. These findings provide evidence that Tbj2 is an orthologue of Yeast DnaJ 1 (Y dj l), an essential S. cerevisiae protein. Hsp40s interact with their partner Hsp70s through their J-domain. The amino acids of the J-domain important for a functional interaction with Hsp70 were examined in Trypanosoma cruzi DnaJ 2 (Tcj2) (the orthologue of Tbj2) and T cruzi DnaJ protein 3 (Tcj3) by testing their ability to substitute for Y dj l in Saccharomyces cerevisae and for DnaJ in Escherichia coli. In both systems, the positively charged amino acids of Helix II and III of the J-domain disrupted the functional interaction of these Hsp40s with their partner Hsp70s. Substitutions in Helix I and IV of the J-domains of Tcj2 and Tcj3 produced varied results in the two different systems, possibly suggesting that these helices serve to define with which Hsp70s a given Hsp40 can interact. The inability of an Hsp40 and an Hsp70 to interact functionally does not necessarily mean a total absence of physical interaction between these proteins. The amino acid substitution of the histidine in the HPD motif (H34Q) of the J-domain of Tcj2 and Tcj3 removed the ability of these proteins to interact functionally with S. cerevisiae Hsp70 (Ssal) in vivo. However, preliminary binding studies using the quartz crystal microbalance with dissipation monitoring (QCM-D) show that Tcj2 and Tcj2(H34Q) both physically interact with M sativa Hsp70 in vitro. This study is the first report to provide evidence that certain trypanosoma! Type 1 Hsp40s are essential proteins. Futhermore, the interaction of these Hsp40s with Hsp70 identified important features of the functional interface of this chaperone machinery.
- Full Text:
- Date Issued: 2010
- Authors: Ludewig, Michael Hans
- Date: 2010
- Subjects: Molecular genetics , Molecular chaperones , Protozoa , Heat shock proteins , Trypanosoma
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4126 , http://hdl.handle.net/10962/d1015205
- Description: Trypanosomes are protozoans, of which many are parasitic, and possess complex lifecycles which alternate between mammalian and arthropod hosts. As is the case with most organisms, molecular chaperones and heat shock proteins are encoded within the genomes of these protozoans. These proteins are an integral part of maintaining the structural integrity of proteins during normal and stress conditions. Heat shock protein 40 (Hsp40) is a co-chaperone of heat shock protein 70 (Hsp70) and in some cases can act as a chaperone. These proteins work together to bind non-native polypeptide structures to prevent unfolded protein aggregrate formation in times of stress, translocate proteins across organelle membranes, and transport unsalvageable proteins to proteolytic degradation by the cellular proteasome. Hsp40s are divided into four types based on their domain structure. Analysis of the nuclear genomes of eight trypanosomatid species revealed that less than 10 of the approximate 70 Hsp40 sequences per genome were Type 1 Hsp40s, many of which contained putative orthologues in the other seven trypanosomatid genomes. One of these Type 1 Hsp40s from T b. brucei, Trypanosoma brucei DnaJ 2 (Tbj2), was functionally characterised in T brucei brucei. RNA interference knockdown of expression in T brucei brucei showed that cells deficient in Tbj2 displayed a severe inhibition of the growth of the cell population. The levels of the Tbj2 protein population in T brucei brucei cells increases after exposure to 42°c and the protein was found to have a generalized cytoplasmic subcellular localization at 37°c. These findings provide evidence that Tbj2 is an orthologue of Yeast DnaJ 1 (Y dj l), an essential S. cerevisiae protein. Hsp40s interact with their partner Hsp70s through their J-domain. The amino acids of the J-domain important for a functional interaction with Hsp70 were examined in Trypanosoma cruzi DnaJ 2 (Tcj2) (the orthologue of Tbj2) and T cruzi DnaJ protein 3 (Tcj3) by testing their ability to substitute for Y dj l in Saccharomyces cerevisae and for DnaJ in Escherichia coli. In both systems, the positively charged amino acids of Helix II and III of the J-domain disrupted the functional interaction of these Hsp40s with their partner Hsp70s. Substitutions in Helix I and IV of the J-domains of Tcj2 and Tcj3 produced varied results in the two different systems, possibly suggesting that these helices serve to define with which Hsp70s a given Hsp40 can interact. The inability of an Hsp40 and an Hsp70 to interact functionally does not necessarily mean a total absence of physical interaction between these proteins. The amino acid substitution of the histidine in the HPD motif (H34Q) of the J-domain of Tcj2 and Tcj3 removed the ability of these proteins to interact functionally with S. cerevisiae Hsp70 (Ssal) in vivo. However, preliminary binding studies using the quartz crystal microbalance with dissipation monitoring (QCM-D) show that Tcj2 and Tcj2(H34Q) both physically interact with M sativa Hsp70 in vitro. This study is the first report to provide evidence that certain trypanosoma! Type 1 Hsp40s are essential proteins. Futhermore, the interaction of these Hsp40s with Hsp70 identified important features of the functional interface of this chaperone machinery.
- Full Text:
- Date Issued: 2010
Three's a crowd: the process of triadic translation in a South African psychiatric institution
- Authors: Slabbert, Meggan
- Date: 2010
- Subjects: Mental health services -- South Africa -- Eastern Cape , Psychiatric hospitals -- South Africa -- Eastern Cape , Translating and interpreting -- Psychological aspects , Translating and interpreting -- Social aspects , Content analysis (Communication) , South Africa -- Languages -- Translating and interpreting , Intercultural communication -- South Africa -- Eastern Cape , Culture conflict -- South Africa -- Eastern Cape , Communication and culture -- South Africa -- Eastern Cape , Physician and patient -- South Africa -- Eastern Cape , Communication in medicine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3056 , http://hdl.handle.net/10962/d1002565 , Mental health services -- South Africa -- Eastern Cape , Psychiatric hospitals -- South Africa -- Eastern Cape , Translating and interpreting -- Psychological aspects , Translating and interpreting -- Social aspects , Content analysis (Communication) , South Africa -- Languages -- Translating and interpreting , Intercultural communication -- South Africa -- Eastern Cape , Culture conflict -- South Africa -- Eastern Cape , Communication and culture -- South Africa -- Eastern Cape , Physician and patient -- South Africa -- Eastern Cape , Communication in medicine -- South Africa -- Eastern Cape
- Description: Mental health care in South Africa has long been governed by inequalities (Foster & Swartz, 1997). During apartheid, those who did not speak English and Afrikaans could not access mental health services in the same way as those who did (Foster & Swartz, 1997). One main reason for this is the majority of mental health practitioners could not, and were not required to speak languages other than English and Afrikaans (Swartz, 1991). The South African mental health literature suggests that language and communication must be prioritised if there is to be an improvement in mental health care services for those individuals who do not speak English and Afrikaans (Bantjes, 1999; Drennan & Swartz, 1999; Swartz & Drennan, 2000; Swartz & MacGregor, 2002). Drawing on Prasad's (2002) interpretation of Gadamer's critical hermeneutic theory and utilising thematic networks analysis (Attride-Stirling, 2001), this study investigated the process of translated clinical assessment interviews within a psychiatric hospital in the Eastern Cape Province within South Africa. Results of the study revealed that contextual factors, issues concerning linguistic and cultural heritage, clinicians' role expectations regarding translators' role performance, as well as relational dynamics regarding individual levels of control and influence within the translation triad, all impacted on the effectiveness of communication, translation and service provision. These fmdings are supported by literature on the theory and practice of translation that identifies these issues as prominent (Robinson, 2003). Specific recommendations regarding the formalisation of translation practices within the hospital setting, as well as the familiari~ation of clinical practitioners and psychiatric nurses with the intricacies of translation processes are offered.
- Full Text:
- Date Issued: 2010
- Authors: Slabbert, Meggan
- Date: 2010
- Subjects: Mental health services -- South Africa -- Eastern Cape , Psychiatric hospitals -- South Africa -- Eastern Cape , Translating and interpreting -- Psychological aspects , Translating and interpreting -- Social aspects , Content analysis (Communication) , South Africa -- Languages -- Translating and interpreting , Intercultural communication -- South Africa -- Eastern Cape , Culture conflict -- South Africa -- Eastern Cape , Communication and culture -- South Africa -- Eastern Cape , Physician and patient -- South Africa -- Eastern Cape , Communication in medicine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3056 , http://hdl.handle.net/10962/d1002565 , Mental health services -- South Africa -- Eastern Cape , Psychiatric hospitals -- South Africa -- Eastern Cape , Translating and interpreting -- Psychological aspects , Translating and interpreting -- Social aspects , Content analysis (Communication) , South Africa -- Languages -- Translating and interpreting , Intercultural communication -- South Africa -- Eastern Cape , Culture conflict -- South Africa -- Eastern Cape , Communication and culture -- South Africa -- Eastern Cape , Physician and patient -- South Africa -- Eastern Cape , Communication in medicine -- South Africa -- Eastern Cape
- Description: Mental health care in South Africa has long been governed by inequalities (Foster & Swartz, 1997). During apartheid, those who did not speak English and Afrikaans could not access mental health services in the same way as those who did (Foster & Swartz, 1997). One main reason for this is the majority of mental health practitioners could not, and were not required to speak languages other than English and Afrikaans (Swartz, 1991). The South African mental health literature suggests that language and communication must be prioritised if there is to be an improvement in mental health care services for those individuals who do not speak English and Afrikaans (Bantjes, 1999; Drennan & Swartz, 1999; Swartz & Drennan, 2000; Swartz & MacGregor, 2002). Drawing on Prasad's (2002) interpretation of Gadamer's critical hermeneutic theory and utilising thematic networks analysis (Attride-Stirling, 2001), this study investigated the process of translated clinical assessment interviews within a psychiatric hospital in the Eastern Cape Province within South Africa. Results of the study revealed that contextual factors, issues concerning linguistic and cultural heritage, clinicians' role expectations regarding translators' role performance, as well as relational dynamics regarding individual levels of control and influence within the translation triad, all impacted on the effectiveness of communication, translation and service provision. These fmdings are supported by literature on the theory and practice of translation that identifies these issues as prominent (Robinson, 2003). Specific recommendations regarding the formalisation of translation practices within the hospital setting, as well as the familiari~ation of clinical practitioners and psychiatric nurses with the intricacies of translation processes are offered.
- Full Text:
- Date Issued: 2010
Rural livelihoods and food security in the aftermath of the fast track land reform in Zimbabwe
- Authors: Jowah, Eddah Vimbai
- Date: 2010
- Subjects: Land reform -- Zimbabwe Food security -- Zimbabwe Sustainable development -- Zimbabwe Right of property -- Zimbabwe Zimbabwe -- Economic conditions Rural development -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3302 , http://hdl.handle.net/10962/d1003090
- Description: Land reforms are back on the development agenda. Different types of land reforms have been adopted globally in recent years, but by far the most controversial and most radical has been the fast track land reform pursued by the Government of Zimbabwe from 2000. There is general scholarly agreement that the fast track process has been accompanied by various socio-economic and political challenges, including an increase in levels of food insecurity. This thesis examines fast track reform in specific relation to the livelihoods of smallholder households and household food security amongst land beneficiaries. It argues that the problem of food insecurity in Zimbabwe is a complex social, political and economic issue, which cannot be simplistically reduced to the failures of fast track. Understanding household food insecurity post-2000 needs to go beyond the notion that the nation‟s food security hinges on overall levels of production alone. In particular, livelihoods and food security need to be conceptualised at community and household levels. Therefore, while addressing the broad macro-level analysis and discourse around the process of fast track, the study also adopts a micro-level analysis to look at the varied impact of fast track on the actual beneficiaries. The research focuses on small-scale beneficiaries in the Goromonzi District of Zimbabwe and, through the use of the sustainable livelihoods framework, looks at how their local contexts have been influenced by the wider socio-economic and political processes, and how beneficiaries have sought ways of coping with the challenges they face.
- Full Text:
- Date Issued: 2010
- Authors: Jowah, Eddah Vimbai
- Date: 2010
- Subjects: Land reform -- Zimbabwe Food security -- Zimbabwe Sustainable development -- Zimbabwe Right of property -- Zimbabwe Zimbabwe -- Economic conditions Rural development -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3302 , http://hdl.handle.net/10962/d1003090
- Description: Land reforms are back on the development agenda. Different types of land reforms have been adopted globally in recent years, but by far the most controversial and most radical has been the fast track land reform pursued by the Government of Zimbabwe from 2000. There is general scholarly agreement that the fast track process has been accompanied by various socio-economic and political challenges, including an increase in levels of food insecurity. This thesis examines fast track reform in specific relation to the livelihoods of smallholder households and household food security amongst land beneficiaries. It argues that the problem of food insecurity in Zimbabwe is a complex social, political and economic issue, which cannot be simplistically reduced to the failures of fast track. Understanding household food insecurity post-2000 needs to go beyond the notion that the nation‟s food security hinges on overall levels of production alone. In particular, livelihoods and food security need to be conceptualised at community and household levels. Therefore, while addressing the broad macro-level analysis and discourse around the process of fast track, the study also adopts a micro-level analysis to look at the varied impact of fast track on the actual beneficiaries. The research focuses on small-scale beneficiaries in the Goromonzi District of Zimbabwe and, through the use of the sustainable livelihoods framework, looks at how their local contexts have been influenced by the wider socio-economic and political processes, and how beneficiaries have sought ways of coping with the challenges they face.
- Full Text:
- Date Issued: 2010
An investigation of prior knowledge about amphibians amongst Grade 7 learners : towards the development of a resource pack
- Authors: Gordon, Louise
- Date: 2010
- Subjects: Amphibians -- Study and teaching -- South Africa Environmental education -- South Africa Natural sciences -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1641 , http://hdl.handle.net/10962/d1003523
- Description: The value of frogs is compared to the value of canaries used in coalmines: they are indicators of the environmental status of our environments, thus crucial to our survival. One third of all frogs worldwide are threatened with extinction. Frogs are found in our immediate environment. Are our Natural Science educators, teaching the Life and Living curriculum aware of this threat, the possible impact that the extinction of frogs will have on our welfare? Are our educators making use of the resources in their immediate environment? This study aimed to investigate the prior knowledge in both the horizontal and vertical discourse, in Grade7 learners and their educators, to inform the design of an amphibian resource pack. By investigating their prior knowledge an insight would be gained in their knowledge of Natural Science concepts as well as their everyday knowledge of their immediate natural environment. It would also highlight any misconceptions formed as well as alternative concepts within both educator and learner groups. These insights would be used to inform the contents of said resource pack.
- Full Text:
- Date Issued: 2010
- Authors: Gordon, Louise
- Date: 2010
- Subjects: Amphibians -- Study and teaching -- South Africa Environmental education -- South Africa Natural sciences -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1641 , http://hdl.handle.net/10962/d1003523
- Description: The value of frogs is compared to the value of canaries used in coalmines: they are indicators of the environmental status of our environments, thus crucial to our survival. One third of all frogs worldwide are threatened with extinction. Frogs are found in our immediate environment. Are our Natural Science educators, teaching the Life and Living curriculum aware of this threat, the possible impact that the extinction of frogs will have on our welfare? Are our educators making use of the resources in their immediate environment? This study aimed to investigate the prior knowledge in both the horizontal and vertical discourse, in Grade7 learners and their educators, to inform the design of an amphibian resource pack. By investigating their prior knowledge an insight would be gained in their knowledge of Natural Science concepts as well as their everyday knowledge of their immediate natural environment. It would also highlight any misconceptions formed as well as alternative concepts within both educator and learner groups. These insights would be used to inform the contents of said resource pack.
- Full Text:
- Date Issued: 2010
Unionism in schools blessing or curse? : a case study of three schools in the Kavango region of Namibia
- Authors: Musore, Pontianus Vitumbo
- Date: 2010
- Subjects: Teachers' unions--Namibia Namibia National Teachers' Union School management and organization--Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1809 , http://hdl.handle.net/10962/d1003695
- Description: This study investigates the role played by the Namibia National Teachers’ Union (NANTU) in school management. It examines the challenges faced by school principals in managing schools as a result of the presence of unions. In order to understand the behaviour and impact of union representatives in schools the study makes use of literature on teacher unionism, democratic, political and ambiguity management and leadership theories. Working in the interpretive orientation the study used semi-structured interviews, document analysis and focus group discussions. The research was conducted in the form of a case study involving three schools in the Kavango region of Namibia, and the data collected were dealt with according to case study principles. The study reveals that the presence of the union has several benefits for the school: for example, it advances the democratic participation of stakeholders, provides feedback to the school principal on how staff members experience his or her leadership, and offers advice on labour-related matters. It was also discovered that NANTU representatives act as mediators in conflict situations, which means that teachers can become better at managing and resolving conflict through their experience of serving on the union structures. However it was also discovered that the presence of NANTU in schools has several negative effects on schooling. For example, NANTU activities can disrupt school programmes; moreover, in some schools, neither NANTU representatives nor school principals understand their own or each other’s roles, and consequently they are always in conflict. The absence of a policy regulating the representation of NANTU in decision-making structures in schools causes the conflict to escalate. It emerged that the role of NANTU in schools is mainly determined by the leadership style of the school principal and the effectiveness of the NANTU representatives in that particular school. For example, an autocratic leadership style on the part of the school principal tends to exacerbate the conflict situation, while NANTU has been known to mobilize learners to demand the removal of school principals through class boycotts. NANTU is more concerned with defending the rights and interests of its members than any other matter affecting education. This research is likely to benefit school managers, policy makers and implementers, and NANTU structures, as it provides clarity on what both NANTU and school principals expect from one another. The study also demonstrates that school principals need to acknowledge and consider the divergent nature of the various interest groups in schools.
- Full Text:
- Date Issued: 2010
- Authors: Musore, Pontianus Vitumbo
- Date: 2010
- Subjects: Teachers' unions--Namibia Namibia National Teachers' Union School management and organization--Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1809 , http://hdl.handle.net/10962/d1003695
- Description: This study investigates the role played by the Namibia National Teachers’ Union (NANTU) in school management. It examines the challenges faced by school principals in managing schools as a result of the presence of unions. In order to understand the behaviour and impact of union representatives in schools the study makes use of literature on teacher unionism, democratic, political and ambiguity management and leadership theories. Working in the interpretive orientation the study used semi-structured interviews, document analysis and focus group discussions. The research was conducted in the form of a case study involving three schools in the Kavango region of Namibia, and the data collected were dealt with according to case study principles. The study reveals that the presence of the union has several benefits for the school: for example, it advances the democratic participation of stakeholders, provides feedback to the school principal on how staff members experience his or her leadership, and offers advice on labour-related matters. It was also discovered that NANTU representatives act as mediators in conflict situations, which means that teachers can become better at managing and resolving conflict through their experience of serving on the union structures. However it was also discovered that the presence of NANTU in schools has several negative effects on schooling. For example, NANTU activities can disrupt school programmes; moreover, in some schools, neither NANTU representatives nor school principals understand their own or each other’s roles, and consequently they are always in conflict. The absence of a policy regulating the representation of NANTU in decision-making structures in schools causes the conflict to escalate. It emerged that the role of NANTU in schools is mainly determined by the leadership style of the school principal and the effectiveness of the NANTU representatives in that particular school. For example, an autocratic leadership style on the part of the school principal tends to exacerbate the conflict situation, while NANTU has been known to mobilize learners to demand the removal of school principals through class boycotts. NANTU is more concerned with defending the rights and interests of its members than any other matter affecting education. This research is likely to benefit school managers, policy makers and implementers, and NANTU structures, as it provides clarity on what both NANTU and school principals expect from one another. The study also demonstrates that school principals need to acknowledge and consider the divergent nature of the various interest groups in schools.
- Full Text:
- Date Issued: 2010
The phytogeography of the Sneeuberg, Nuweveldberge and Roggeveldberge (Great Escarpment): assessing migration routes and endemism
- Authors: Clark, Vincent Ralph
- Date: 2010
- Subjects: Phytogeography -- South Africa Endemic plants -- South Africa Plants -- Migration -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4187 , http://hdl.handle.net/10962/d1003756
- Description: The Great Escarpment forms a semi-continuous mountain system 5 000 km long, stretching from Angola in the north-west, south through Namibia, and into western, southern and eastern South Africa, including Lesotho and Swaziland. It is composed of a wide variety of geological suites but is unified in representing the edge of the African plateau and the passive Gondwanan continental margin. The Great Escarpment falls into all major climatic zones on the subcontinent, is a repository of palaeo- and neo-endemics, hosts more than half of southern Africa‟s centres of plant endemism, and has a rich suite of endemic fauna. In addition, the Great Escarpment is believed to be both a refugium and corridor for biological diversity. Despite the biological richness of the Great Escarpment, research to date has been fragmented and many sections of the Great Escarpment have not been studied. The aim of this study is to contribute to research on the Great Escarpment by undertaking a detailed floristic study of the southern Great Escarpment (the Sneeuberg, Nuweveldberge and Roggeveldberge). Together these mountains comprise approximately 1 000 km (one fifth) of the Great Escarpment, and occupy a transition zone between the summer rainfall zone in the east and the winter rainfall zone in the west. They are also the sections of Great Escarpment most closely situated to the Cape Floristic Region (CFR) and would thus be involved in hypothesised migration routes for lineages that also occur further north through the Drakensberg Alpine Centre (DAC) to the East African mountain chain. Detailed fieldwork of the southern Great Escarpment was undertaken over a period of four years in all seasons. Approximately 8 000 specimens were collected. Particular emphasis was placed on areas that may represent refugia, i.e. the highest plateaux and peaks, mesic areas and cliff-lines. An overview of each mountain range, together with their endemic plant species and phytogeography, is provided. Approximately ten new species have been discovered during this study, two of which have been described to date. Numerous endemics only known from their types have also been rediscovered. The Sneeuberg is defined as a new centre of plant endemism on the Great Escarpment (endemism of 2.3%), and the role of the Boschberg and Groot-Bruintjieshoogde (part of the Sneeuberg) as a nexus for floristic migration routes is discussed. The Nuweveldberge is shown to have low endemism despite a floristic tally similar to the Sneeuberg, while the Roggeveldberge are confirmed to be the most endemic-rich section of the southern Great Escarpment. The field data collected was augmented by available data in taxonomic revisions, and floras for the Sneeuberg, Nuweveldberge and Roggeveldberge were compiled. In order to floristically compare the southern Great Escarpment with other sections of the Great Escarpment and the CFR, a database of some 12 000 taxa was created using available floristic data for the CFR, DAC and Great WinterbergAmatolas, together with the data collated for the Sneeuberg, Nuweveldberge and Roggeveldberge. These data were analysed using phenetic methods and Parsimony Analysis of Endemicity (PAE). The results indicate stronger linkages in the east, particularly between the Sneeuberg and Nuweveldberge, and between the Sneeuberg and the Great WinterbergAmatolas. The relationship of the Roggeveldberge with the rest of the southern Great Escarpment remains ambiguous. In order to refine notions of connectivity and migration routes, 19 well-sampled phylogenies were assessed for sister-taxon disjunctions to explore CFRGreat Escarpment connections. Palaeo-connectivity between the CFR and southern Great Escarpment is most strongly supported for the south-eastern (SE) connection, and less so for the north-western (NW) and Matjiesfontein connections. There is support for the current (or recent) use of these three connections from numerous species that occur on both sides of the connections. Results of these analyses indicate that the southern Great Escarpment is a palaeo-corridor, the functioning of which has been broken by the aridification of the Nuweveldberge since the Last Glacial Maximum (LGM). Floristic connectivity is strongest in the east, from the Nuweveldberge to the DAC, and is less so in the west between the Nuweveldberge and the Roggeveldberge a finding attributed to the transition from a reliable winter rainfall regime on the Roggeveldberge to an unpredictable moisture regime on the Nuweveldberge. The mountains of the southern Great Escarpment are thus a series of refugia from a previous moister, cooler climate and are a corridor between the eastern and western components of the Great Escarpment. The SE connection is the primary link between the CFR and the eastern Great Escarpment Afromontane region in southern Africa. The implications of this research are that accurate conservation assessments and Red Data listings for many of the previously poorly-known endemics can now be made, and appropriate conservation measures implemented. Climate change remains the primary threat to these endemics and montane taxa in general, while degradation of wetlands is the primary threat to the water catchment service provided by the southern Great Escarpment. Future detailed research on the Great WinterbergAmatolas and Stormberg and a comprehensive flora of the HantamRoggeveldberge will further enhance our understanding of the floristics of the southern Great Escarpment, and provide the necessary data for comprehensive GIS-based models of proposed climate change scenarios for local, regional and national conservation planning.
- Full Text:
- Date Issued: 2010
- Authors: Clark, Vincent Ralph
- Date: 2010
- Subjects: Phytogeography -- South Africa Endemic plants -- South Africa Plants -- Migration -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4187 , http://hdl.handle.net/10962/d1003756
- Description: The Great Escarpment forms a semi-continuous mountain system 5 000 km long, stretching from Angola in the north-west, south through Namibia, and into western, southern and eastern South Africa, including Lesotho and Swaziland. It is composed of a wide variety of geological suites but is unified in representing the edge of the African plateau and the passive Gondwanan continental margin. The Great Escarpment falls into all major climatic zones on the subcontinent, is a repository of palaeo- and neo-endemics, hosts more than half of southern Africa‟s centres of plant endemism, and has a rich suite of endemic fauna. In addition, the Great Escarpment is believed to be both a refugium and corridor for biological diversity. Despite the biological richness of the Great Escarpment, research to date has been fragmented and many sections of the Great Escarpment have not been studied. The aim of this study is to contribute to research on the Great Escarpment by undertaking a detailed floristic study of the southern Great Escarpment (the Sneeuberg, Nuweveldberge and Roggeveldberge). Together these mountains comprise approximately 1 000 km (one fifth) of the Great Escarpment, and occupy a transition zone between the summer rainfall zone in the east and the winter rainfall zone in the west. They are also the sections of Great Escarpment most closely situated to the Cape Floristic Region (CFR) and would thus be involved in hypothesised migration routes for lineages that also occur further north through the Drakensberg Alpine Centre (DAC) to the East African mountain chain. Detailed fieldwork of the southern Great Escarpment was undertaken over a period of four years in all seasons. Approximately 8 000 specimens were collected. Particular emphasis was placed on areas that may represent refugia, i.e. the highest plateaux and peaks, mesic areas and cliff-lines. An overview of each mountain range, together with their endemic plant species and phytogeography, is provided. Approximately ten new species have been discovered during this study, two of which have been described to date. Numerous endemics only known from their types have also been rediscovered. The Sneeuberg is defined as a new centre of plant endemism on the Great Escarpment (endemism of 2.3%), and the role of the Boschberg and Groot-Bruintjieshoogde (part of the Sneeuberg) as a nexus for floristic migration routes is discussed. The Nuweveldberge is shown to have low endemism despite a floristic tally similar to the Sneeuberg, while the Roggeveldberge are confirmed to be the most endemic-rich section of the southern Great Escarpment. The field data collected was augmented by available data in taxonomic revisions, and floras for the Sneeuberg, Nuweveldberge and Roggeveldberge were compiled. In order to floristically compare the southern Great Escarpment with other sections of the Great Escarpment and the CFR, a database of some 12 000 taxa was created using available floristic data for the CFR, DAC and Great WinterbergAmatolas, together with the data collated for the Sneeuberg, Nuweveldberge and Roggeveldberge. These data were analysed using phenetic methods and Parsimony Analysis of Endemicity (PAE). The results indicate stronger linkages in the east, particularly between the Sneeuberg and Nuweveldberge, and between the Sneeuberg and the Great WinterbergAmatolas. The relationship of the Roggeveldberge with the rest of the southern Great Escarpment remains ambiguous. In order to refine notions of connectivity and migration routes, 19 well-sampled phylogenies were assessed for sister-taxon disjunctions to explore CFRGreat Escarpment connections. Palaeo-connectivity between the CFR and southern Great Escarpment is most strongly supported for the south-eastern (SE) connection, and less so for the north-western (NW) and Matjiesfontein connections. There is support for the current (or recent) use of these three connections from numerous species that occur on both sides of the connections. Results of these analyses indicate that the southern Great Escarpment is a palaeo-corridor, the functioning of which has been broken by the aridification of the Nuweveldberge since the Last Glacial Maximum (LGM). Floristic connectivity is strongest in the east, from the Nuweveldberge to the DAC, and is less so in the west between the Nuweveldberge and the Roggeveldberge a finding attributed to the transition from a reliable winter rainfall regime on the Roggeveldberge to an unpredictable moisture regime on the Nuweveldberge. The mountains of the southern Great Escarpment are thus a series of refugia from a previous moister, cooler climate and are a corridor between the eastern and western components of the Great Escarpment. The SE connection is the primary link between the CFR and the eastern Great Escarpment Afromontane region in southern Africa. The implications of this research are that accurate conservation assessments and Red Data listings for many of the previously poorly-known endemics can now be made, and appropriate conservation measures implemented. Climate change remains the primary threat to these endemics and montane taxa in general, while degradation of wetlands is the primary threat to the water catchment service provided by the southern Great Escarpment. Future detailed research on the Great WinterbergAmatolas and Stormberg and a comprehensive flora of the HantamRoggeveldberge will further enhance our understanding of the floristics of the southern Great Escarpment, and provide the necessary data for comprehensive GIS-based models of proposed climate change scenarios for local, regional and national conservation planning.
- Full Text:
- Date Issued: 2010
Spatial and temporal patterns in the hyperbenthic community structure in a permanently open Eastern Cape estuary, South Africa
- Authors: Heyns, Elodie R
- Date: 2010
- Subjects: Sundays Estuary -- South Africa -- Eastern Cape , Groundfishes -- South Africa -- Eatern Cape , Estuaries -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5768 , http://hdl.handle.net/10962/d1005456
- Description: The spatial and temporal (seasonal and diel) patterns in the hyperbenthic community structure (>500 μm) was investigated in the warm temperate, permanently open Kariega Estuary situated along the south-eastern coastline of South Africa. Spatial and seasonal patterns in the hyperbenthic community structure were assessed monthly at six stations along the length of the estuary over a period of twelve months. Data were collected using a modified hyperbenthic sledge, comprising two super-imposed nets. Physico-chemical data indicate the presence of a constant reverse salinity gradient, with highest salinities measured in the upper reaches and lowest at the mouth of the estuary. Strong seasonal patterns in temperature, dissolved oxygen and total chlorophyll-a (chl-a) concentrations were evident. Total average hyperbenthic densities ranged between 0.04 and 166 ind.m-3 in the lower net and between 0.12 and 225 ind.m-3 in the upper net. Hyperbenthic biomass values ranged between 0.02 and 11.9 mg.dry weight.m-3 in the lower net and between 0.02 and 17.4 mg.dry weight.m-3 in the upper net. A spatial and temporal pattern in total densities was detected with an increase in abundance over the period of September to October 2008 particularly in the middle reaches (Stations 3 and 4). Both the lower and upper nets were numerically dominated by decapods (mainly brachyuran crab zoeae) with the exception of June and July 2008 when mysids (mainly Mesopodopsis wooldridgei) dominated, making up 72.4 ± 58.14% of the total abundance in the lower net. A redundancy analysis (RDA) indicated that 99.2% of the variance in the hyperbenthic community structure could be explained by the first two canonical axes. Axis one, which accounted for 96.8% of the total variation detected in the ordination plot was highly correlated with sedimentary organic content and to a lesser extent the chl-a concentration within the Kariega Estuary. The correlations with the second canonical axis (2.4%) were less obvious, however, salinity and seston concentration were weakly correlated with this axis. Diel variability in the hyperbenthic community structure was assessed during March 2009. Samples were collected during the day and night (n = 6 for each period) using sampling gear described above. Total average hyperbenthic densities during the day (497.9 ± 254.1 ind.m-3) were significantly higher than night-time estimates (129.9 ± 38.5 ind.m-3; p<0.05). There were no significant differences in the average dayand night-time estimates of hyperbenthic biomass (p>0.05). A hierarchical cluster analysis identified two significantly distinct groupings, designated the day and night samples. Results from the SIMPER procedure indicated that the high densities of crab zoeae recorded during the day-time accounted for the majority of the dissimilarity between the day and night groupings (44.7%). In addition, it is apparent that several benthic species, especially from the cumacean and isopod orders, were absent from the hyperbenthos during the day-time and emerged into the water column at night.
- Full Text:
- Date Issued: 2010
- Authors: Heyns, Elodie R
- Date: 2010
- Subjects: Sundays Estuary -- South Africa -- Eastern Cape , Groundfishes -- South Africa -- Eatern Cape , Estuaries -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5768 , http://hdl.handle.net/10962/d1005456
- Description: The spatial and temporal (seasonal and diel) patterns in the hyperbenthic community structure (>500 μm) was investigated in the warm temperate, permanently open Kariega Estuary situated along the south-eastern coastline of South Africa. Spatial and seasonal patterns in the hyperbenthic community structure were assessed monthly at six stations along the length of the estuary over a period of twelve months. Data were collected using a modified hyperbenthic sledge, comprising two super-imposed nets. Physico-chemical data indicate the presence of a constant reverse salinity gradient, with highest salinities measured in the upper reaches and lowest at the mouth of the estuary. Strong seasonal patterns in temperature, dissolved oxygen and total chlorophyll-a (chl-a) concentrations were evident. Total average hyperbenthic densities ranged between 0.04 and 166 ind.m-3 in the lower net and between 0.12 and 225 ind.m-3 in the upper net. Hyperbenthic biomass values ranged between 0.02 and 11.9 mg.dry weight.m-3 in the lower net and between 0.02 and 17.4 mg.dry weight.m-3 in the upper net. A spatial and temporal pattern in total densities was detected with an increase in abundance over the period of September to October 2008 particularly in the middle reaches (Stations 3 and 4). Both the lower and upper nets were numerically dominated by decapods (mainly brachyuran crab zoeae) with the exception of June and July 2008 when mysids (mainly Mesopodopsis wooldridgei) dominated, making up 72.4 ± 58.14% of the total abundance in the lower net. A redundancy analysis (RDA) indicated that 99.2% of the variance in the hyperbenthic community structure could be explained by the first two canonical axes. Axis one, which accounted for 96.8% of the total variation detected in the ordination plot was highly correlated with sedimentary organic content and to a lesser extent the chl-a concentration within the Kariega Estuary. The correlations with the second canonical axis (2.4%) were less obvious, however, salinity and seston concentration were weakly correlated with this axis. Diel variability in the hyperbenthic community structure was assessed during March 2009. Samples were collected during the day and night (n = 6 for each period) using sampling gear described above. Total average hyperbenthic densities during the day (497.9 ± 254.1 ind.m-3) were significantly higher than night-time estimates (129.9 ± 38.5 ind.m-3; p<0.05). There were no significant differences in the average dayand night-time estimates of hyperbenthic biomass (p>0.05). A hierarchical cluster analysis identified two significantly distinct groupings, designated the day and night samples. Results from the SIMPER procedure indicated that the high densities of crab zoeae recorded during the day-time accounted for the majority of the dissimilarity between the day and night groupings (44.7%). In addition, it is apparent that several benthic species, especially from the cumacean and isopod orders, were absent from the hyperbenthos during the day-time and emerged into the water column at night.
- Full Text:
- Date Issued: 2010
An environmental education portfolio: three small scale studies informing school greening activities and professional development of teachers in two rural Eastern Cape schools in SANBI's Greening the Nation Project
- Authors: Finca, Moffat Nkosiphendule
- Date: 2010
- Subjects: South African National Biodiversity Institute Environmental education -- South Africa -- Eastern Cape Teachers -- In-service training -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1737 , http://hdl.handle.net/10962/d1003621
- Full Text:
- Date Issued: 2010
- Authors: Finca, Moffat Nkosiphendule
- Date: 2010
- Subjects: South African National Biodiversity Institute Environmental education -- South Africa -- Eastern Cape Teachers -- In-service training -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1737 , http://hdl.handle.net/10962/d1003621
- Full Text:
- Date Issued: 2010
Movement patterns and population dynamics of four catsharks endemic to South Africa
- Authors: Escobar-Porras, Jessica
- Date: 2010
- Subjects: Chondrichthyes -- South Africa , Fish populations -- South Africa , Fishes -- Behavior -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5303 , http://hdl.handle.net/10962/d1005148 , Chondrichthyes -- South Africa , Fish populations -- South Africa , Fishes -- Behavior -- South Africa
- Description: Sharks are particularly vulnerable to over-exploitation. Although catsharks are an important component of the near-shore marine biodiversity in South Africa and most of the species are endemic, little is known about their movement patterns, home range and population size. With an increasing number of recreational fishers this information is crucial for their conservation. The aims of this study were threefold. Firstly, to identify and analyze existing data sources on movement patterns and population dynamics for four catshark species: pyjama (Poroderma africanum), leopard (P. pantherinum), puffadder (Haploblepharus edwarsii) and brown (H. fuscus). This highlighted a number of shortcomings with existing data sets, largely because these studies had diverse objectives and were not aimed solely at catsharks. Secondly, a dedicated study was carried out for a limited area, testing a number of methods for data collection, and where appropriate the data was analyzed to determine movement patterns and population numbers. Thirdly, the most appropriate methodology for future studies (with similar objectives) was identified, and the results of the study were used to propose a number of conservation measures. All species of catsharks exhibited strong site fidelity and limited dispersal for extended periods. A few individuals did, however, travel distances in excess of 150 km. Significant trends in temporal abundance were not observed, nevertheless, there was some evidence for higher catches from September to December. Population estimates for the study area were low, with P. africanum having the smallest population size while H. fuscus had the highest population size within the restricted study area. Limited movements, high site fidelity and small population sizes emphasize their vulnerability and suggest that catsharks would benefit from no-take marine protected areas.
- Full Text:
- Date Issued: 2010
- Authors: Escobar-Porras, Jessica
- Date: 2010
- Subjects: Chondrichthyes -- South Africa , Fish populations -- South Africa , Fishes -- Behavior -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5303 , http://hdl.handle.net/10962/d1005148 , Chondrichthyes -- South Africa , Fish populations -- South Africa , Fishes -- Behavior -- South Africa
- Description: Sharks are particularly vulnerable to over-exploitation. Although catsharks are an important component of the near-shore marine biodiversity in South Africa and most of the species are endemic, little is known about their movement patterns, home range and population size. With an increasing number of recreational fishers this information is crucial for their conservation. The aims of this study were threefold. Firstly, to identify and analyze existing data sources on movement patterns and population dynamics for four catshark species: pyjama (Poroderma africanum), leopard (P. pantherinum), puffadder (Haploblepharus edwarsii) and brown (H. fuscus). This highlighted a number of shortcomings with existing data sets, largely because these studies had diverse objectives and were not aimed solely at catsharks. Secondly, a dedicated study was carried out for a limited area, testing a number of methods for data collection, and where appropriate the data was analyzed to determine movement patterns and population numbers. Thirdly, the most appropriate methodology for future studies (with similar objectives) was identified, and the results of the study were used to propose a number of conservation measures. All species of catsharks exhibited strong site fidelity and limited dispersal for extended periods. A few individuals did, however, travel distances in excess of 150 km. Significant trends in temporal abundance were not observed, nevertheless, there was some evidence for higher catches from September to December. Population estimates for the study area were low, with P. africanum having the smallest population size while H. fuscus had the highest population size within the restricted study area. Limited movements, high site fidelity and small population sizes emphasize their vulnerability and suggest that catsharks would benefit from no-take marine protected areas.
- Full Text:
- Date Issued: 2010
Disjunctures within conventional knowledge of black male homosexual identity in contemporary South Africa
- Authors: Li, Xinling
- Date: 2010
- Subjects: Mead, George Herbert 1863-1931 , Foucault, Michel, 1926-1984 , Butler, Judith, 1956- , Gay men, Black -- South Africa , Lesbians -- South Africa , Gender identity -- South Africa , Homosexuality -- South Africa , Identity (Psychology) -- South Africa , Gender identity -- Social aspects
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3297 , http://hdl.handle.net/10962/d1003085 , Mead, George Herbert 1863-1931 , Foucault, Michel, 1926-1984 , Butler, Judith, 1956- , Gay men, Black -- South Africa , Lesbians -- South Africa , Gender identity -- South Africa , Homosexuality -- South Africa , Identity (Psychology) -- South Africa , Gender identity -- Social aspects
- Description: This thesis provides a sociological understanding of how conventional knowledge of sexuality negates the identity formation of black gay men in contemporary South Africa. It investigates the coming out experiences of six black gay men in order to reveal the disjunctures between being black and being gay. The theoretical formation of disjuncture is pursued through examining a number of sociological, historical, psychoanalytical, and feminist approaches to identity, sexuality, and society; featuring specifically the theories of George Herbert Mead, Michel Foucault, and Judith Butler. The chosen research paradigm is symbolic interactionism, postulating both „pragmatist‟ and „empiricist‟ trends that lead to both interactionist and structuralist forms of argumentation. The interactionist approach to sexuality is central to the deconstruction of sexual conventions. It involves conceptualising modern sexuality in the landscapes of African colonial history and the global gay and lesbian movement. The prescribed literature on homosexuality is thus reviewed in conjunction with the South African gay and lesbian struggle, so as to spawn themes and perspectives for conducting life story interviews. The use of the life story interview favours the participants‟ own view of the studied phenomenon, yet aims to depict the structural influence on homosexual identification. Following the qualitative research tradition, the data analysis is based on the interpretation of narratives. It illustrates interpersonal relationships and microscopic experiences that lead to the self-acceptance and self-actualisation of homosexuality. Within these processes, various disjunctures that exist between the cultural sanction of lifestyle and individual choice, between parents and children, between religious belief and personal desires, and between gender identity and sexual orientation are disclosed. The findings are associated with the historical transformation of masculinity in South Africa, sex role performance, and the heterosexualisation of desire. The solution to the proposed research problem is discussed through concepts of socialisation and gender conformity.
- Full Text:
- Date Issued: 2010
- Authors: Li, Xinling
- Date: 2010
- Subjects: Mead, George Herbert 1863-1931 , Foucault, Michel, 1926-1984 , Butler, Judith, 1956- , Gay men, Black -- South Africa , Lesbians -- South Africa , Gender identity -- South Africa , Homosexuality -- South Africa , Identity (Psychology) -- South Africa , Gender identity -- Social aspects
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3297 , http://hdl.handle.net/10962/d1003085 , Mead, George Herbert 1863-1931 , Foucault, Michel, 1926-1984 , Butler, Judith, 1956- , Gay men, Black -- South Africa , Lesbians -- South Africa , Gender identity -- South Africa , Homosexuality -- South Africa , Identity (Psychology) -- South Africa , Gender identity -- Social aspects
- Description: This thesis provides a sociological understanding of how conventional knowledge of sexuality negates the identity formation of black gay men in contemporary South Africa. It investigates the coming out experiences of six black gay men in order to reveal the disjunctures between being black and being gay. The theoretical formation of disjuncture is pursued through examining a number of sociological, historical, psychoanalytical, and feminist approaches to identity, sexuality, and society; featuring specifically the theories of George Herbert Mead, Michel Foucault, and Judith Butler. The chosen research paradigm is symbolic interactionism, postulating both „pragmatist‟ and „empiricist‟ trends that lead to both interactionist and structuralist forms of argumentation. The interactionist approach to sexuality is central to the deconstruction of sexual conventions. It involves conceptualising modern sexuality in the landscapes of African colonial history and the global gay and lesbian movement. The prescribed literature on homosexuality is thus reviewed in conjunction with the South African gay and lesbian struggle, so as to spawn themes and perspectives for conducting life story interviews. The use of the life story interview favours the participants‟ own view of the studied phenomenon, yet aims to depict the structural influence on homosexual identification. Following the qualitative research tradition, the data analysis is based on the interpretation of narratives. It illustrates interpersonal relationships and microscopic experiences that lead to the self-acceptance and self-actualisation of homosexuality. Within these processes, various disjunctures that exist between the cultural sanction of lifestyle and individual choice, between parents and children, between religious belief and personal desires, and between gender identity and sexual orientation are disclosed. The findings are associated with the historical transformation of masculinity in South Africa, sex role performance, and the heterosexualisation of desire. The solution to the proposed research problem is discussed through concepts of socialisation and gender conformity.
- Full Text:
- Date Issued: 2010
A narrative analysis of young black South African women's stories about the recent divorce of their parents
- Authors: Lotter, Jaclyn Oehley
- Date: 2010
- Subjects: Divorce -- South Africa Divorce -- Psychological aspects -- South Africa Children of divorced parents -- South Africa Families -- South Africa Divorce therapy -- South Africa Adolescent psychotherapy -- South Africa Youth, Black -- Counseling of -- South Africa Psychology -- Biographical methods -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3011 , http://hdl.handle.net/10962/d1002520
- Description: The global rise in divorce since the 1960s has brought into question the idealised view of the nuclear family which has for centuries been awarded special status in western societies and has been regarded as the primary social institution. According to contemporary research parental divorce has become a reality for every one in six children in South Africa. Until recently, little consideration had been given to how divorce affects black South African families, as it was considered to be an occurrence which only took place in white, mainly middle-class, families. The proportion of black South African couples divorcing has been increasing over the past decade, and in 2008 was said to contribute to 35% of all divorce in South Africa. Most research to date on the children of divorce has focused on young white children and adolescents and is largely concerned with those who have found parental divorce particularly difficult, and are manifesting adjustment and other behavioural problems. The research which has been done on the effects of parental divorce on young adults focuses mainly on clinical studies with middle-class families based either in the United States or in the United Kingdom. This research, using an experience-centred, life-story narrative approach, explores the stories which young black South African adult women between the ages of 18 and 25 tell, to give account to the ways in which recent parental divorce has affected their lives, views on family life, and what it has meant to them. The use of an experience-centred, life-story narrative approach allows for a process of rupture, acceptance and re-storying to be accounted for, as the participant’s narrative shifts from past, to present and the future. Five young black women from a South African university each participated in two narratively sequenced semi-structured interviews based on McAdams’ personal narratives protocol, which includes six core themes, namely: Key Events, Significant People, Stresses and Problems, Personal Meanings and Life-Lessons, Future Script, and Life Theme. Crossley’s narrative analysis was then used to identify emergent themes and images in each individual narrative, after which they were woven together into a coherent story linked to previous literature. This study found that divorce involves a highly complex transition and reconfiguration process perhaps not fully accounted for in the existing idea and images associated with it. Despite being young adult women who had moved away from home and were engaged in their own lives, it became apparent that parental divorce was still a difficult and complicated experience, but that it is possible to tell both pessimistic and optimistic stories of parental divorce and its consequences.
- Full Text:
- Date Issued: 2010
- Authors: Lotter, Jaclyn Oehley
- Date: 2010
- Subjects: Divorce -- South Africa Divorce -- Psychological aspects -- South Africa Children of divorced parents -- South Africa Families -- South Africa Divorce therapy -- South Africa Adolescent psychotherapy -- South Africa Youth, Black -- Counseling of -- South Africa Psychology -- Biographical methods -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3011 , http://hdl.handle.net/10962/d1002520
- Description: The global rise in divorce since the 1960s has brought into question the idealised view of the nuclear family which has for centuries been awarded special status in western societies and has been regarded as the primary social institution. According to contemporary research parental divorce has become a reality for every one in six children in South Africa. Until recently, little consideration had been given to how divorce affects black South African families, as it was considered to be an occurrence which only took place in white, mainly middle-class, families. The proportion of black South African couples divorcing has been increasing over the past decade, and in 2008 was said to contribute to 35% of all divorce in South Africa. Most research to date on the children of divorce has focused on young white children and adolescents and is largely concerned with those who have found parental divorce particularly difficult, and are manifesting adjustment and other behavioural problems. The research which has been done on the effects of parental divorce on young adults focuses mainly on clinical studies with middle-class families based either in the United States or in the United Kingdom. This research, using an experience-centred, life-story narrative approach, explores the stories which young black South African adult women between the ages of 18 and 25 tell, to give account to the ways in which recent parental divorce has affected their lives, views on family life, and what it has meant to them. The use of an experience-centred, life-story narrative approach allows for a process of rupture, acceptance and re-storying to be accounted for, as the participant’s narrative shifts from past, to present and the future. Five young black women from a South African university each participated in two narratively sequenced semi-structured interviews based on McAdams’ personal narratives protocol, which includes six core themes, namely: Key Events, Significant People, Stresses and Problems, Personal Meanings and Life-Lessons, Future Script, and Life Theme. Crossley’s narrative analysis was then used to identify emergent themes and images in each individual narrative, after which they were woven together into a coherent story linked to previous literature. This study found that divorce involves a highly complex transition and reconfiguration process perhaps not fully accounted for in the existing idea and images associated with it. Despite being young adult women who had moved away from home and were engaged in their own lives, it became apparent that parental divorce was still a difficult and complicated experience, but that it is possible to tell both pessimistic and optimistic stories of parental divorce and its consequences.
- Full Text:
- Date Issued: 2010