Tufa stromatolite ecosystems on the South African south coast
- Perissinotto, Renzo, Bornman, Tommy G, Steyn, Paul-Pierre, Miranda, Nelson A F, Dorrington, Rosemary A, Matcher, Gwynneth F, Strydom, Nadine A, Peer, Nasreen
- Authors: Perissinotto, Renzo , Bornman, Tommy G , Steyn, Paul-Pierre , Miranda, Nelson A F , Dorrington, Rosemary A , Matcher, Gwynneth F , Strydom, Nadine A , Peer, Nasreen
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6490 , http://hdl.handle.net/10962/d1014585 , http://dx.doi.org/10.1590/sajs.2014/20140011
- Description: Following the first description of living marine stromatolites along the South African east coast, new investigations along the south coast have revealed the occurrence of extensive fields of actively calcifying stromatolites. These stromatolites have been recorded at regular distances along a 200-km stretch of coastline, from Cape Recife in the east to the Storms River mouth in the west, with the highest density found between Schoenmakerskop and the Maitland River mouth. All active stromatolites are associated with freshwater seepage streams flowing from the dune cordon, which form rimstone dams and other accretions capable of retaining water in the supratidal platform. Resulting pools can reach a maximum depth of about 1 m and constitute a unique ecosystem in which freshwater and marine organisms alternate their dominance in response to vertical mixing and the balance between freshwater versus marine inflow. Although the factors controlling stromatolite growth are yet to be determined, nitrogen appears to be supplied mainly via the dune seeps. The epibenthic algal community within stromatolite pools is generally co-dominated by cyanobacteria and chlorophytes, with minimal diatom contribution.
- Full Text:
- Authors: Perissinotto, Renzo , Bornman, Tommy G , Steyn, Paul-Pierre , Miranda, Nelson A F , Dorrington, Rosemary A , Matcher, Gwynneth F , Strydom, Nadine A , Peer, Nasreen
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6490 , http://hdl.handle.net/10962/d1014585 , http://dx.doi.org/10.1590/sajs.2014/20140011
- Description: Following the first description of living marine stromatolites along the South African east coast, new investigations along the south coast have revealed the occurrence of extensive fields of actively calcifying stromatolites. These stromatolites have been recorded at regular distances along a 200-km stretch of coastline, from Cape Recife in the east to the Storms River mouth in the west, with the highest density found between Schoenmakerskop and the Maitland River mouth. All active stromatolites are associated with freshwater seepage streams flowing from the dune cordon, which form rimstone dams and other accretions capable of retaining water in the supratidal platform. Resulting pools can reach a maximum depth of about 1 m and constitute a unique ecosystem in which freshwater and marine organisms alternate their dominance in response to vertical mixing and the balance between freshwater versus marine inflow. Although the factors controlling stromatolite growth are yet to be determined, nitrogen appears to be supplied mainly via the dune seeps. The epibenthic algal community within stromatolite pools is generally co-dominated by cyanobacteria and chlorophytes, with minimal diatom contribution.
- Full Text:
Unclogging the wheels: how the shift from politics to law affects Africa's relationship with the international system
- Authors: Juma, Laurence
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127123 , vital:35958 , https://heinonline.org/HOL/Page?handle=hein.journals/tlcp23amp;div=17amp;g_sent=1amp;casa_token=amp;collection=journals
- Description: Gone are the days when scholars debated whether international law was really law and whether the adjudicatory organs of the international system could effectuate the demands of the international rule of law. 1 This old time debate has, in recent times, given way to temperate and yet decisive acknowledgement of the legal authority of institutions resident within the international system.
- Full Text: false
- Authors: Juma, Laurence
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127123 , vital:35958 , https://heinonline.org/HOL/Page?handle=hein.journals/tlcp23amp;div=17amp;g_sent=1amp;casa_token=amp;collection=journals
- Description: Gone are the days when scholars debated whether international law was really law and whether the adjudicatory organs of the international system could effectuate the demands of the international rule of law. 1 This old time debate has, in recent times, given way to temperate and yet decisive acknowledgement of the legal authority of institutions resident within the international system.
- Full Text: false
Understanding and modelling of surface and groundwater interactions
- Authors: Tanner, Jane Louise
- Date: 2014
- Subjects: Groundwater -- South Africa , Water-supply -- Management , Integrated water development , Hydrogeology , Water resources development -- South Africa , Water -- Analysis , Groundwater -- Management , Watersheds -- South Africa , Hydrologic models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6043 , http://hdl.handle.net/10962/d1012994
- Description: The connections between surface water and groundwater systems remain poorly understood in many catchments throughout the world and yet they are fundamental to effectively managing water resources. Managing water resources in an integrated manner is not straightforward, particularly if both resources are being utilised, and especially in those regions that suffer problems of data scarcity. This study explores some of the principle issues associated with understanding and practically modelling surface and groundwater interactions. In South Africa, there remains much controversy over the most appropriate type of integrated model to be used and the way forward in terms of the development of the discipline; part of the disagreement stems from the fact that we cannot validate models adequately. This is largely due to traditional forms of model testing having limited power as it is difficult to differentiate between the uncertainties within different model structures, different sets of alternative parameter values and in the input data used to run the model. While model structural uncertainties are important to consider, the uncertainty from input data error together with parameter estimation error are often more significant to the overall residual error, and essential to consider if we want to achieve reliable predictions for water resource decisions. While new philosophies and theories on modelling and results validation have been developed (Beven, 2002; Gupta et al., 2008), in many cases models are not only still being validated and compared using sparse and uncertain datasets, but also expected to produce reliable predictions based on the flawed data. The approach in this study is focused on fundamental understanding of hydrological systems rather than calibration based modelling and promotes the use of all the available 'hard' and 'soft' data together with thoughtful conceptual examination of the processes occurring in an environment to ensure as far as possible that a model is generating sensible results by simulating the correct processes. The first part of the thesis focuses on characterising the 'typical' interaction environments found in South Africa. It was found that many traditional perceptual models are not necessarily applicable to South African conditions, largely due to the relative importance of unsaturated zone processes and the complexity of the dominantly fractured rock environments. The interaction environments were categorised into four main 'types' of environment. These include karst, primary, fractured rock (secondary), and alluvial environments. Processes critical to Integrated Water Resource Management (IWRM) were defined within each interaction type as a guideline to setting a model up to realistically represent the dominant processes in the respective settings. The second part of the thesis addressed the application and evaluation of the modified Pitman model (Hughes, 2004), which allows for surface and groundwater interaction behaviour at the catchment scale to be simulated. The issue is whether, given the different sources of uncertainty in the modelling process, we can differentiate one conceptual flow path from another in trying to refine the understanding and consequently have more faith in model predictions. Seven example catchments were selected from around South Africa to assess whether reliable integrated assessments can be carried out given the existing data. Specific catchment perceptual models were used to identify the critical processes occurring in each setting and the Pitman model was assessed on whether it could represent them (structural uncertainty). The available knowledge of specific environments or catchments was then examined in an attempt to resolve the parameter uncertainty present within each catchment and ensure the subsequent model setup was correctly representing the process understanding as far as possible. The confidence in the quantitative results inevitably varied with the amount and quality of the data available. While the model was deemed to be robust based on the behavioural results obtained in the majority of the case studies, in many cases a quantitative validation of the outputs was just not possible based on the available data. In these cases, the model was judged on its ability to represent the conceptualisation of the processes occurring in the catchments. While the lack of appropriate data means there will always be considerable uncertainty surrounding model validation, it can be argued that improved process understanding in an environment can be used to validate model outcomes to a degree, by assessing whether a model is getting the right results for the right reasons. Many water resource decisions are still made without adequate account being taken of the uncertainties inherent in assessing the response of hydrological systems. Certainly, with all the possible sources of uncertainty in a data scarce country such as South Africa, pure calibration based modelling is unlikely to produce reliable information for water resource managers as it can produce the right results for the wrong reasons. Thus it becomes essential to incorporate conceptual thinking into the modelling process, so that at the very least we are able to conclude that a model generates estimates that are consistent with, and reflect, our understanding (however limited) of the catchment processes. It is fairly clear that achieving the optimum model of a hydrological system may be fraught with difficulty, if not impossible. This makes it very difficult from a practitioner's point of view to decide which model and uncertainty estimation method to use. According to Beven (2009), this may be a transitional problem and in the future it may become clearer as we learn more about how to estimate the uncertainties associated with hydrological systems. Until then, a better understanding of the fundamental and most critical hydrogeological processes should be used to critically test and improve model predictions as far as possible. A major focus of the study was to identify whether the modified Pitman model could provide a practical tool for water resource managers by reliably determining the available water resource. The incorporation of surface and groundwater interaction routines seems to have resulted in a more robust and realistic model of basin hydrology. The overall conclusion is that the model, although simplified, is capable of representing the catchment scale processes that occur under most South African conditions.
- Full Text:
- Authors: Tanner, Jane Louise
- Date: 2014
- Subjects: Groundwater -- South Africa , Water-supply -- Management , Integrated water development , Hydrogeology , Water resources development -- South Africa , Water -- Analysis , Groundwater -- Management , Watersheds -- South Africa , Hydrologic models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6043 , http://hdl.handle.net/10962/d1012994
- Description: The connections between surface water and groundwater systems remain poorly understood in many catchments throughout the world and yet they are fundamental to effectively managing water resources. Managing water resources in an integrated manner is not straightforward, particularly if both resources are being utilised, and especially in those regions that suffer problems of data scarcity. This study explores some of the principle issues associated with understanding and practically modelling surface and groundwater interactions. In South Africa, there remains much controversy over the most appropriate type of integrated model to be used and the way forward in terms of the development of the discipline; part of the disagreement stems from the fact that we cannot validate models adequately. This is largely due to traditional forms of model testing having limited power as it is difficult to differentiate between the uncertainties within different model structures, different sets of alternative parameter values and in the input data used to run the model. While model structural uncertainties are important to consider, the uncertainty from input data error together with parameter estimation error are often more significant to the overall residual error, and essential to consider if we want to achieve reliable predictions for water resource decisions. While new philosophies and theories on modelling and results validation have been developed (Beven, 2002; Gupta et al., 2008), in many cases models are not only still being validated and compared using sparse and uncertain datasets, but also expected to produce reliable predictions based on the flawed data. The approach in this study is focused on fundamental understanding of hydrological systems rather than calibration based modelling and promotes the use of all the available 'hard' and 'soft' data together with thoughtful conceptual examination of the processes occurring in an environment to ensure as far as possible that a model is generating sensible results by simulating the correct processes. The first part of the thesis focuses on characterising the 'typical' interaction environments found in South Africa. It was found that many traditional perceptual models are not necessarily applicable to South African conditions, largely due to the relative importance of unsaturated zone processes and the complexity of the dominantly fractured rock environments. The interaction environments were categorised into four main 'types' of environment. These include karst, primary, fractured rock (secondary), and alluvial environments. Processes critical to Integrated Water Resource Management (IWRM) were defined within each interaction type as a guideline to setting a model up to realistically represent the dominant processes in the respective settings. The second part of the thesis addressed the application and evaluation of the modified Pitman model (Hughes, 2004), which allows for surface and groundwater interaction behaviour at the catchment scale to be simulated. The issue is whether, given the different sources of uncertainty in the modelling process, we can differentiate one conceptual flow path from another in trying to refine the understanding and consequently have more faith in model predictions. Seven example catchments were selected from around South Africa to assess whether reliable integrated assessments can be carried out given the existing data. Specific catchment perceptual models were used to identify the critical processes occurring in each setting and the Pitman model was assessed on whether it could represent them (structural uncertainty). The available knowledge of specific environments or catchments was then examined in an attempt to resolve the parameter uncertainty present within each catchment and ensure the subsequent model setup was correctly representing the process understanding as far as possible. The confidence in the quantitative results inevitably varied with the amount and quality of the data available. While the model was deemed to be robust based on the behavioural results obtained in the majority of the case studies, in many cases a quantitative validation of the outputs was just not possible based on the available data. In these cases, the model was judged on its ability to represent the conceptualisation of the processes occurring in the catchments. While the lack of appropriate data means there will always be considerable uncertainty surrounding model validation, it can be argued that improved process understanding in an environment can be used to validate model outcomes to a degree, by assessing whether a model is getting the right results for the right reasons. Many water resource decisions are still made without adequate account being taken of the uncertainties inherent in assessing the response of hydrological systems. Certainly, with all the possible sources of uncertainty in a data scarce country such as South Africa, pure calibration based modelling is unlikely to produce reliable information for water resource managers as it can produce the right results for the wrong reasons. Thus it becomes essential to incorporate conceptual thinking into the modelling process, so that at the very least we are able to conclude that a model generates estimates that are consistent with, and reflect, our understanding (however limited) of the catchment processes. It is fairly clear that achieving the optimum model of a hydrological system may be fraught with difficulty, if not impossible. This makes it very difficult from a practitioner's point of view to decide which model and uncertainty estimation method to use. According to Beven (2009), this may be a transitional problem and in the future it may become clearer as we learn more about how to estimate the uncertainties associated with hydrological systems. Until then, a better understanding of the fundamental and most critical hydrogeological processes should be used to critically test and improve model predictions as far as possible. A major focus of the study was to identify whether the modified Pitman model could provide a practical tool for water resource managers by reliably determining the available water resource. The incorporation of surface and groundwater interaction routines seems to have resulted in a more robust and realistic model of basin hydrology. The overall conclusion is that the model, although simplified, is capable of representing the catchment scale processes that occur under most South African conditions.
- Full Text:
Understanding development aid and state autonomy : the case of European Union budget support to Mozambique
- Authors: Ndlovu, Ana Admiração
- Date: 2014
- Subjects: Economic assistance, European -- Mozambique , Economic development -- Mozambique , Mozambique -- Economic conditions , Autonomy , Budget -- Mozambique
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3378 , http://hdl.handle.net/10962/d1013218
- Description: Post-colonial states in Africa continue to pursue nation-building and socio-economic development. This process is taking place with the sustained support of global agencies in terms of development cooperation, assistance and aid. Insofar as an endogenous development path which speaks to national priorities can be formulated and implemented by post-colonial states, their relationship with these agencies raises serious questions about such a path if the relationship entails dependence and indeed subordination of post-colonial states. This raises important questions about state autonomy under post-colonial conditions and the possibility of autonomy being compromised. In this light, the thesis examines European Union budget support to Mozambique and, in particular, the relationship between EU budget support and Mozambique state autonomy in pursuing national development. This is particularly pertinent given the massive dependence of the Mozambican state on foreign funding (notably EU funding) with specific regard to the national budget. Despite the broad claims existing in the prevailing literature that nation-state autonomy is seriously undermined in and through the international development system, the thesis argues against reductionist arguments that simply posit post-colonial states as mere instruments of global forces. This system, including European Union budget support, does indeed set the conditions of existence for post-colonial states such as Mozambique. But autonomy is necessarily relative and is subject to different forms and degrees. Ultimately, it is through empirical investigation that the specific form and degree of autonomy can be pinpointed and understood. The thesis contributes to this endeavour and suggests that the relationship between European budget support and Mozambican state autonomy is more complex and tension-riddled than the prevailing literature would seem to suggest.
- Full Text:
- Authors: Ndlovu, Ana Admiração
- Date: 2014
- Subjects: Economic assistance, European -- Mozambique , Economic development -- Mozambique , Mozambique -- Economic conditions , Autonomy , Budget -- Mozambique
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3378 , http://hdl.handle.net/10962/d1013218
- Description: Post-colonial states in Africa continue to pursue nation-building and socio-economic development. This process is taking place with the sustained support of global agencies in terms of development cooperation, assistance and aid. Insofar as an endogenous development path which speaks to national priorities can be formulated and implemented by post-colonial states, their relationship with these agencies raises serious questions about such a path if the relationship entails dependence and indeed subordination of post-colonial states. This raises important questions about state autonomy under post-colonial conditions and the possibility of autonomy being compromised. In this light, the thesis examines European Union budget support to Mozambique and, in particular, the relationship between EU budget support and Mozambique state autonomy in pursuing national development. This is particularly pertinent given the massive dependence of the Mozambican state on foreign funding (notably EU funding) with specific regard to the national budget. Despite the broad claims existing in the prevailing literature that nation-state autonomy is seriously undermined in and through the international development system, the thesis argues against reductionist arguments that simply posit post-colonial states as mere instruments of global forces. This system, including European Union budget support, does indeed set the conditions of existence for post-colonial states such as Mozambique. But autonomy is necessarily relative and is subject to different forms and degrees. Ultimately, it is through empirical investigation that the specific form and degree of autonomy can be pinpointed and understood. The thesis contributes to this endeavour and suggests that the relationship between European budget support and Mozambican state autonomy is more complex and tension-riddled than the prevailing literature would seem to suggest.
- Full Text:
Understanding educators' and learners' perceptions and experiences of their participation in Science Fairs/Expos : a South African case study.
- Authors: Kahenge, Wendelina Nambahu
- Date: 2014
- Subjects: Science fairs -- South Africa -- Grahamstown , Science -- Study and teaching -- South Africa -- Grahamstown , Vocational guidance -- South Africa -- Grahamstown , School children -- South Africa -- Attitudes , Teachers -- South Africa -- Attitudes , Teacher effectiveness -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1981 , http://hdl.handle.net/10962/d1013130
- Description: The rationale behind Science Expos is to develop and empower learners to be able to identify problems and find solutions (Eskom Expo Project Guide Book, 2013). It is believed that involvement in Science Expos arouses learners' interest to pursue science related careers. But despite these ideals, there is still poor participation in Science Expos by educators and learners. I conducted this case study in five schools in Grahamstown, Eastern Cape, South Africa. The purpose of this study was to understand educators' and learners' perceptions and experiences of their participation in Science Expos. The case study was designed within an interpretive paradigm. The data were generated, triangulated and validated by a variety of methods, namely, document analysis, interviews (semi-structured and focus group) and observations. The main findings of the study were that learners who participate in Science Expos attend workshops organised by Scifest and SAEON office with the help of some of the educators and lecturers from Rhodes University. Learners' participation was influenced and assisted by the educators and peers with whom they were able to communicate and share their projects with. It emerged from the study that, as a result of participating in Science Expos, educators (teachers) and learners were exposed to a wide variety of scientific investigations and skills that are necessary for their classroom based-scientific investigations. It also emerged from this study that educators and learners face the challenge of a lack of motivation; insufficient support from schools and parents; time constraints to support learners in their participation and a lack of knowledge among some educators on their learners' projects. Some learners are even discouraged from participating in Science Expos by their peers on the grounds that they have no chance of winning. Teachers therefore require continuous mentorship and capacity building in order to encourage their learners to partake.
- Full Text:
- Authors: Kahenge, Wendelina Nambahu
- Date: 2014
- Subjects: Science fairs -- South Africa -- Grahamstown , Science -- Study and teaching -- South Africa -- Grahamstown , Vocational guidance -- South Africa -- Grahamstown , School children -- South Africa -- Attitudes , Teachers -- South Africa -- Attitudes , Teacher effectiveness -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1981 , http://hdl.handle.net/10962/d1013130
- Description: The rationale behind Science Expos is to develop and empower learners to be able to identify problems and find solutions (Eskom Expo Project Guide Book, 2013). It is believed that involvement in Science Expos arouses learners' interest to pursue science related careers. But despite these ideals, there is still poor participation in Science Expos by educators and learners. I conducted this case study in five schools in Grahamstown, Eastern Cape, South Africa. The purpose of this study was to understand educators' and learners' perceptions and experiences of their participation in Science Expos. The case study was designed within an interpretive paradigm. The data were generated, triangulated and validated by a variety of methods, namely, document analysis, interviews (semi-structured and focus group) and observations. The main findings of the study were that learners who participate in Science Expos attend workshops organised by Scifest and SAEON office with the help of some of the educators and lecturers from Rhodes University. Learners' participation was influenced and assisted by the educators and peers with whom they were able to communicate and share their projects with. It emerged from the study that, as a result of participating in Science Expos, educators (teachers) and learners were exposed to a wide variety of scientific investigations and skills that are necessary for their classroom based-scientific investigations. It also emerged from this study that educators and learners face the challenge of a lack of motivation; insufficient support from schools and parents; time constraints to support learners in their participation and a lack of knowledge among some educators on their learners' projects. Some learners are even discouraged from participating in Science Expos by their peers on the grounds that they have no chance of winning. Teachers therefore require continuous mentorship and capacity building in order to encourage their learners to partake.
- Full Text:
Understanding food security in a perfect storm: an ecosystem services approach
- Poppy, G M, Chiotha, S, Eigenbrod, Felix, Harvey, Celia A, Honza´k, M, Hudson, Malcolm D, Jarvis, A, Madise, Nyovani J, Schreckenberg, Kate, Shackleton, Charlie M, Villa, F, Dawson, Terrence P
- Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, Celia A , Honza´k, M , Hudson, Malcolm D , Jarvis, A , Madise, Nyovani J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, F , Dawson, Terrence P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398423 , vital:69410 , xlink:href="https://doi.org/10.1098/rstb.2012.0288"
- Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
- Full Text:
- Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, Celia A , Honza´k, M , Hudson, Malcolm D , Jarvis, A , Madise, Nyovani J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, F , Dawson, Terrence P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398423 , vital:69410 , xlink:href="https://doi.org/10.1098/rstb.2012.0288"
- Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
- Full Text:
Understanding how trainee teachers engage with prior everyday knowledge and experience associated with biological concepts during integrated natural science education 5-7 : a case study
- Authors: Enghono, Albertina Magano
- Date: 2014
- Subjects: Biology teachers -- Training of -- Namibia -- Case studies Teacher educators -- Training of -- Case studies Teachers -- Training of -- Namibia -- Case studies Education -- Namibia -- Case studies Prior learning -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1970 , http://hdl.handle.net/10962/d1011972
- Description: Since the Namibian independence in 1990, the education system has undergone some major revamping which involved the adoption of social constructivist perspectives in the teaching and learning of sciences. This learning theory acknowledges learners’ background prior knowledge as valuable tools in the effective construction of science concepts during lessons. A corollary is that the socio-cultural circumstances of learners might negatively influence the way learners construct new knowledge in the science classroom if they are not taken into consideration. This study was thus prompted by the need to understand how trainee science teachers engage with prior everyday knowledge and experiences, so as to enhance the conceptual development of biological concepts. The study was qualitative and it was underpinned by an interpretive paradigm with some elements of action research. Science trainee teachers at Katima Mulilo, Unam Campus were used as research participants. The techniques used to gather data included document analysis, brainstorming, observation, audio-visual, microteaching and semi-structured interviews. The results of this study showed that the changes that occurred during microteaching practices of the four trainee teachers involved in the study reflected their professional development in this approach. However, it emerged that prior everyday knowledge can be both a barrier and enabler to the construction of meaningful teaching and learning; hence its oversight may lead to instructional failures. The findings also indicated that selected platforms are essential to enable trainee teachers to incorporate prior everyday knowledge and experiences into the teaching of Western science. However, larger scale study should be conducted in order to deepen the understanding of the topic.
- Full Text:
- Authors: Enghono, Albertina Magano
- Date: 2014
- Subjects: Biology teachers -- Training of -- Namibia -- Case studies Teacher educators -- Training of -- Case studies Teachers -- Training of -- Namibia -- Case studies Education -- Namibia -- Case studies Prior learning -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1970 , http://hdl.handle.net/10962/d1011972
- Description: Since the Namibian independence in 1990, the education system has undergone some major revamping which involved the adoption of social constructivist perspectives in the teaching and learning of sciences. This learning theory acknowledges learners’ background prior knowledge as valuable tools in the effective construction of science concepts during lessons. A corollary is that the socio-cultural circumstances of learners might negatively influence the way learners construct new knowledge in the science classroom if they are not taken into consideration. This study was thus prompted by the need to understand how trainee science teachers engage with prior everyday knowledge and experiences, so as to enhance the conceptual development of biological concepts. The study was qualitative and it was underpinned by an interpretive paradigm with some elements of action research. Science trainee teachers at Katima Mulilo, Unam Campus were used as research participants. The techniques used to gather data included document analysis, brainstorming, observation, audio-visual, microteaching and semi-structured interviews. The results of this study showed that the changes that occurred during microteaching practices of the four trainee teachers involved in the study reflected their professional development in this approach. However, it emerged that prior everyday knowledge can be both a barrier and enabler to the construction of meaningful teaching and learning; hence its oversight may lead to instructional failures. The findings also indicated that selected platforms are essential to enable trainee teachers to incorporate prior everyday knowledge and experiences into the teaching of Western science. However, larger scale study should be conducted in order to deepen the understanding of the topic.
- Full Text:
Understanding the livelihoods of child-grant mothers in Sinathingi in KwaZulu-Natal, South Africa
- Motsetse, Matsepo Nomathemba
- Authors: Motsetse, Matsepo Nomathemba
- Date: 2014
- Subjects: Welfare recipients -- South Africa -- KwaZulu-Natal , Social security -- South Africa , Family policy -- South Africa , Women -- South Africa -- KwaZulu-Natal -- Social conditions , Women -- South Africa -- KwaZulu-Natal -- Economic conditions , Poverty -- South Africa , Income -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3380 , http://hdl.handle.net/10962/d1013284
- Description: The main focus of this thesis is the child support grant, as part of a broader social security system, in post-apartheid South Africa. Since the end of apartheid of 1994, the new South African government has sought to redress the racial imbalances and inequalities of the past by engaging in measures of redistribution. Central to this pursuit of redistribution has been a restructured system of social grants, of which the child support grant is the most significant. However, the post-apartheid government has adopted a largely neo-liberal macro-economic strategy such that social inequality and endemic poverty remain pervasive particularly amongst the African population, which includes the recipients of the child support grants. In adopting a sustainable livelihoods framework as the main theoretical perspective, the thesis seeks to understand the livelihoods of child support grant mothers in the face of conditions of extreme poverty. It does this through a localised study of twenty child grant mothers in Sinathingi Township in KwaZulu-Natal Province. In examining the livelihoods of these child-grant mothers, the thesis brings to the fore that mothers and their children do not exist as autonomous living units but are embedded in a broader set of social relations, including intra-household relations and relations with the fathers of the grant-children. It also demonstrates that child-grant mothers are not simply victims of structures of poverty in contemporary South Africa, but actively construct their livelihoods through a range of activities and strategies which show perseverance and ingenuity.
- Full Text:
- Authors: Motsetse, Matsepo Nomathemba
- Date: 2014
- Subjects: Welfare recipients -- South Africa -- KwaZulu-Natal , Social security -- South Africa , Family policy -- South Africa , Women -- South Africa -- KwaZulu-Natal -- Social conditions , Women -- South Africa -- KwaZulu-Natal -- Economic conditions , Poverty -- South Africa , Income -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3380 , http://hdl.handle.net/10962/d1013284
- Description: The main focus of this thesis is the child support grant, as part of a broader social security system, in post-apartheid South Africa. Since the end of apartheid of 1994, the new South African government has sought to redress the racial imbalances and inequalities of the past by engaging in measures of redistribution. Central to this pursuit of redistribution has been a restructured system of social grants, of which the child support grant is the most significant. However, the post-apartheid government has adopted a largely neo-liberal macro-economic strategy such that social inequality and endemic poverty remain pervasive particularly amongst the African population, which includes the recipients of the child support grants. In adopting a sustainable livelihoods framework as the main theoretical perspective, the thesis seeks to understand the livelihoods of child support grant mothers in the face of conditions of extreme poverty. It does this through a localised study of twenty child grant mothers in Sinathingi Township in KwaZulu-Natal Province. In examining the livelihoods of these child-grant mothers, the thesis brings to the fore that mothers and their children do not exist as autonomous living units but are embedded in a broader set of social relations, including intra-household relations and relations with the fathers of the grant-children. It also demonstrates that child-grant mothers are not simply victims of structures of poverty in contemporary South Africa, but actively construct their livelihoods through a range of activities and strategies which show perseverance and ingenuity.
- Full Text:
Understanding the replication biology of Providence virus: elucidating the function of non-structural proteins
- Authors: Nakayinga, Ritah
- Date: 2014
- Subjects: Insects Viruses , Viruses Reproduction , Tombusviridae , RNA viruses , RNA polymerases
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193930 , vital:45408
- Description: Tetraviruses are non-enveloped, small insect RNA viruses with a single stranded positive RNA genome that is either monopartite or bipartite. Providence virus (PrV) is the only member of the three tetravirus families with a viral replicase similar to the replicases of tombusviruses and umbraviruses. The principle aim of this thesis was to study PrV replication, focusing on subcellular localization and potential interactions between PrV replication proteins. The first objective of this study was to generate an anti-p104 antibody that does not cross-react with p40. Expression of the C-terminal portion of p104 in E. coli resulted in no detectable protein. Further expression in an insect cell based expression system resulted in the production of an insoluble protein. Attempts to improve protein solubility with a range of solubilization treatments were unsuccessful. Bioinformatic analysis was used to detect an antigenic region at the C-terminus of p104 and the peptide was used to raise anti-p104 antibodies. These antibodies did not detect native protein by western blot detection however they were used for immunoprecipitation. The establishment of the subcellular localization of PrV required two approaches; immunofluorescence in persistently infected Helicoverpa zea MG8 cells using antip40 and anti-dsRNA antibodies and the expression of EGFP-replicase fusion protein in Spodoptera frugiperda Sf9 cells. Replication of PrV was found to take place in cytosolic punctate structures. Co-immunoprecipitation experiments revealed that p40 self-interacts and interacts with p104. Bioinformatic analysis of PrV p104 suggests that the RdRp is similar to viral RdRps of the carmo-like supergroup II. Potential RNA binding regions are present within p104. A potential p40 interaction domain that shares hydrophilic and surface exposed properties with the TBSV p33 interaction domain is present. A putative arginine-rich region and disordered C-terminal region is present in p130. In conclusion, PrV p104 is the viral replicase. The resemblance of the expression strategy and putative functional domains with tombusviruses and umbraviruses suggest that PrV replication is related to the replication system of the tombusviruses and umbraviruses. This has led to propose that tetravirus replication strategies are diverse and raises questions on the origin and evolution of PrV. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
- Full Text:
- Authors: Nakayinga, Ritah
- Date: 2014
- Subjects: Insects Viruses , Viruses Reproduction , Tombusviridae , RNA viruses , RNA polymerases
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193930 , vital:45408
- Description: Tetraviruses are non-enveloped, small insect RNA viruses with a single stranded positive RNA genome that is either monopartite or bipartite. Providence virus (PrV) is the only member of the three tetravirus families with a viral replicase similar to the replicases of tombusviruses and umbraviruses. The principle aim of this thesis was to study PrV replication, focusing on subcellular localization and potential interactions between PrV replication proteins. The first objective of this study was to generate an anti-p104 antibody that does not cross-react with p40. Expression of the C-terminal portion of p104 in E. coli resulted in no detectable protein. Further expression in an insect cell based expression system resulted in the production of an insoluble protein. Attempts to improve protein solubility with a range of solubilization treatments were unsuccessful. Bioinformatic analysis was used to detect an antigenic region at the C-terminus of p104 and the peptide was used to raise anti-p104 antibodies. These antibodies did not detect native protein by western blot detection however they were used for immunoprecipitation. The establishment of the subcellular localization of PrV required two approaches; immunofluorescence in persistently infected Helicoverpa zea MG8 cells using antip40 and anti-dsRNA antibodies and the expression of EGFP-replicase fusion protein in Spodoptera frugiperda Sf9 cells. Replication of PrV was found to take place in cytosolic punctate structures. Co-immunoprecipitation experiments revealed that p40 self-interacts and interacts with p104. Bioinformatic analysis of PrV p104 suggests that the RdRp is similar to viral RdRps of the carmo-like supergroup II. Potential RNA binding regions are present within p104. A potential p40 interaction domain that shares hydrophilic and surface exposed properties with the TBSV p33 interaction domain is present. A putative arginine-rich region and disordered C-terminal region is present in p130. In conclusion, PrV p104 is the viral replicase. The resemblance of the expression strategy and putative functional domains with tombusviruses and umbraviruses suggest that PrV replication is related to the replication system of the tombusviruses and umbraviruses. This has led to propose that tetravirus replication strategies are diverse and raises questions on the origin and evolution of PrV. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
- Full Text:
Understanding the sexual practices of medically circumcised males in the context of HIV and AIDS : a study in Harare Zimbabwe
- Authors: Chamuka, Paidashe
- Date: 2014
- Subjects: Circumcision -- Zimbabwe , Men -- Sexual behavior -- Zimbabwe -- Case studies , AIDS (Disease) -- Zimbabwe -- Prevention , HIV infections -- South Africa -- Prevention
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3363 , http://hdl.handle.net/10962/d1011745 , Circumcision -- Zimbabwe , Men -- Sexual behavior -- Zimbabwe -- Case studies , AIDS (Disease) -- Zimbabwe -- Prevention , HIV infections -- South Africa -- Prevention
- Description: Zimbabwe is one of the priority countries nominated by the World Health Organisation and the Joint United Nations Programme on HIV and AIDS to adopt and implement voluntary medical male circumcision (VMMC) because of its high rate of HIV prevalence and its low level of male circumcision. VMMC, which was introduced in Zimbabwe in 2009, is a new HIV prevention method which reportedly offers partial protection of about 60 percent for circumcised males with respect to contracting HIV through sexual relations. The other key prevention method, namely the use of condoms consistently and correctly, has a protection rate of up to 95 percent. As a result, because of only partial protection, medically-circumcised men are encouraged to use condoms to decrease the chances of HIV infection. Concerns though have been raised about the possibility of risk compensation by circumcised males by way of increases in unsafe or risky sexual practices subsequent to circumcision and arising from perceptions of reduced risk through VMMC. This compensation may take the form of condom use aversion including when involved with concurrent sexual partners. If risk compensation does take place, this would lead to increases in HIV transmissions affecting not only the circumcised men but their sexual partners as well. The supposed effectiveness of VMMC as a HIV prevention method has been subjected to significant criticism and, as yet, no significant study has been undertaken in Zimbabwe on the relationship between VMMC, condom use, concurrent sexual partners and risk compensation. Based on a study of twenty-five medically-circumcised males in Harare, the capital of Zimbabwe, this thesis seeks to understand and explain the relationship between voluntary medical male circumcision and risky sexual practices with particular reference to condom use amongst men engaged in concurrent sexual partnerships. While the thesis finds evidence of risky sexual practices subsequent to circumcision, risk compensation does not seem to be particularly prevalent.
- Full Text:
- Authors: Chamuka, Paidashe
- Date: 2014
- Subjects: Circumcision -- Zimbabwe , Men -- Sexual behavior -- Zimbabwe -- Case studies , AIDS (Disease) -- Zimbabwe -- Prevention , HIV infections -- South Africa -- Prevention
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3363 , http://hdl.handle.net/10962/d1011745 , Circumcision -- Zimbabwe , Men -- Sexual behavior -- Zimbabwe -- Case studies , AIDS (Disease) -- Zimbabwe -- Prevention , HIV infections -- South Africa -- Prevention
- Description: Zimbabwe is one of the priority countries nominated by the World Health Organisation and the Joint United Nations Programme on HIV and AIDS to adopt and implement voluntary medical male circumcision (VMMC) because of its high rate of HIV prevalence and its low level of male circumcision. VMMC, which was introduced in Zimbabwe in 2009, is a new HIV prevention method which reportedly offers partial protection of about 60 percent for circumcised males with respect to contracting HIV through sexual relations. The other key prevention method, namely the use of condoms consistently and correctly, has a protection rate of up to 95 percent. As a result, because of only partial protection, medically-circumcised men are encouraged to use condoms to decrease the chances of HIV infection. Concerns though have been raised about the possibility of risk compensation by circumcised males by way of increases in unsafe or risky sexual practices subsequent to circumcision and arising from perceptions of reduced risk through VMMC. This compensation may take the form of condom use aversion including when involved with concurrent sexual partners. If risk compensation does take place, this would lead to increases in HIV transmissions affecting not only the circumcised men but their sexual partners as well. The supposed effectiveness of VMMC as a HIV prevention method has been subjected to significant criticism and, as yet, no significant study has been undertaken in Zimbabwe on the relationship between VMMC, condom use, concurrent sexual partners and risk compensation. Based on a study of twenty-five medically-circumcised males in Harare, the capital of Zimbabwe, this thesis seeks to understand and explain the relationship between voluntary medical male circumcision and risky sexual practices with particular reference to condom use amongst men engaged in concurrent sexual partnerships. While the thesis finds evidence of risky sexual practices subsequent to circumcision, risk compensation does not seem to be particularly prevalent.
- Full Text:
Undertaking to care and to protect : The experience of killing healthy homeless animals in South Africa
- Authors: Van Zyl, Henriette Louise
- Date: 2014
- Subjects: Animal welfare -- Moral and ethical aspects -- South Africa , Euthanasia of animals -- South Africa , Euthanasia of animals -- Psychological aspects , Human-animal relationships -- South Africa , Animal rights -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3245 , http://hdl.handle.net/10962/d1013577
- Description: Although animal welfare workers overwhelmingly describe themselves as animal lovers the exigencies of day to day animal welfare work often require that they perform euthanasia of healthy animals as part of welfare shelter management, and animal population control. In this research study, the particular burdens placed upon seven South Animal welfare workers who are required to rescue, care for, nurture and rehabilitate the animals in their care; while simultaneously being required to kill these same – often physically and behaviourally healthy - animals after a specific period of time, or in response to various logistical, procedural and practical intricacies, ranging from lack of space and resources to an unavailability of suitable homes; are explored from an interpretative phenomenological approach using the Interpretative Phenomenological Method (IPA), and from a South African perspective. It was found that animal-loving individuals engaged in the care and subsequent euthanasia of healthy animals report experiencing profound personal, interpersonal and professional and ideological (dis)stress related to guilt, sorrow, moral unease and horror. Four themes emerged from interview data, which are discussed in relation to relevant research and literature. Experiences in a South African context were found to be very much aligned with those reported in previous research and literature pertaining to this topic. In particular, it was found that there is a need to articulate specifically, and precisely the nature of the act. It is proposed that the term “Agapéthanasia” would be appropriate and useful in this field.
- Full Text:
- Authors: Van Zyl, Henriette Louise
- Date: 2014
- Subjects: Animal welfare -- Moral and ethical aspects -- South Africa , Euthanasia of animals -- South Africa , Euthanasia of animals -- Psychological aspects , Human-animal relationships -- South Africa , Animal rights -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3245 , http://hdl.handle.net/10962/d1013577
- Description: Although animal welfare workers overwhelmingly describe themselves as animal lovers the exigencies of day to day animal welfare work often require that they perform euthanasia of healthy animals as part of welfare shelter management, and animal population control. In this research study, the particular burdens placed upon seven South Animal welfare workers who are required to rescue, care for, nurture and rehabilitate the animals in their care; while simultaneously being required to kill these same – often physically and behaviourally healthy - animals after a specific period of time, or in response to various logistical, procedural and practical intricacies, ranging from lack of space and resources to an unavailability of suitable homes; are explored from an interpretative phenomenological approach using the Interpretative Phenomenological Method (IPA), and from a South African perspective. It was found that animal-loving individuals engaged in the care and subsequent euthanasia of healthy animals report experiencing profound personal, interpersonal and professional and ideological (dis)stress related to guilt, sorrow, moral unease and horror. Four themes emerged from interview data, which are discussed in relation to relevant research and literature. Experiences in a South African context were found to be very much aligned with those reported in previous research and literature pertaining to this topic. In particular, it was found that there is a need to articulate specifically, and precisely the nature of the act. It is proposed that the term “Agapéthanasia” would be appropriate and useful in this field.
- Full Text:
Unsymmetrically substituted nickel triazatetra-benzcorrole and phthalocynanine complexes
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189818 , vital:44934 , xlink:href="https://doi.org/10.1007/s10895-013-1317-4"
- Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs.
- Full Text:
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189818 , vital:44934 , xlink:href="https://doi.org/10.1007/s10895-013-1317-4"
- Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs.
- Full Text:
Using multivariate analysis and stable isotopes to assess the effects of substrate type on phytobenthos communities
- Dalu, Tatenda, Richoux, Nicole B, Froneman, P William
- Authors: Dalu, Tatenda , Richoux, Nicole B , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68123 , vital:29201 , https://doi.org/10.5268/IW-4.4.719
- Description: Publisher version , For more than a century, artificial substrates have been employed in phytobenthos studies. In the present study, we compared the phytobenthos community structure in a field experiment over 3 seasons (summer, autumn, and winter) on 3 types of artificial substrates (brick, brown clay tiles, and grey clay tiles) and 3 natural substrates (macrophytes, rocks, and sediment) in a small, temperate system. A combination of multivariate analyses (cluster, multi-response permutation procedure, indicator species [IndVal], and canonical correspondence analysis [CCA]) and stable isotope analysis was used. We identified 96 total phytobenthos taxa. Artificial substrates resulted in different substrate communities, as shown by stable isotope analysis, cluster analysis, and a multi-response permutation procedure, with only those communities growing on grey tiles being similar to natural substrate communities. Overall, artificial substrates exhibited slightly higher species richness compared to natural substrates over the 3 seasons, although there were no significant differences (p> 0.05). Phytobenthos grown on brown tiles, rocks, and bricks showed seasonal variability of the carbon isotope δ13C values using one-way ANOVA (p< 0.05). Phytobenthos community structure did not show great seasonal variation; however, CCA identified water flow, conductivity, ammonium, phosphate, and water depth as important in structuring phytobenthos communities on different substrates. IndVal analysis showed that common phytobenthos taxa were not restricted to a single substrate, but preference was generally high for natural substrate, especially rocks, compared to artificial substrates. Substrate microhabitat type seems to influence the communities within the study areas.
- Full Text: false
- Authors: Dalu, Tatenda , Richoux, Nicole B , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68123 , vital:29201 , https://doi.org/10.5268/IW-4.4.719
- Description: Publisher version , For more than a century, artificial substrates have been employed in phytobenthos studies. In the present study, we compared the phytobenthos community structure in a field experiment over 3 seasons (summer, autumn, and winter) on 3 types of artificial substrates (brick, brown clay tiles, and grey clay tiles) and 3 natural substrates (macrophytes, rocks, and sediment) in a small, temperate system. A combination of multivariate analyses (cluster, multi-response permutation procedure, indicator species [IndVal], and canonical correspondence analysis [CCA]) and stable isotope analysis was used. We identified 96 total phytobenthos taxa. Artificial substrates resulted in different substrate communities, as shown by stable isotope analysis, cluster analysis, and a multi-response permutation procedure, with only those communities growing on grey tiles being similar to natural substrate communities. Overall, artificial substrates exhibited slightly higher species richness compared to natural substrates over the 3 seasons, although there were no significant differences (p> 0.05). Phytobenthos grown on brown tiles, rocks, and bricks showed seasonal variability of the carbon isotope δ13C values using one-way ANOVA (p< 0.05). Phytobenthos community structure did not show great seasonal variation; however, CCA identified water flow, conductivity, ammonium, phosphate, and water depth as important in structuring phytobenthos communities on different substrates. IndVal analysis showed that common phytobenthos taxa were not restricted to a single substrate, but preference was generally high for natural substrate, especially rocks, compared to artificial substrates. Substrate microhabitat type seems to influence the communities within the study areas.
- Full Text: false
Utilizing gesture recognition and Ethernet AVB for distributed surround sound control
- Hedges, Mitchell, Foss, Richard
- Authors: Hedges, Mitchell , Foss, Richard
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426816 , vital:72393 , https://www.aes.org/e-lib/online/browse.cfm?elib=17540
- Description: Gesture recognition has become a preferred approach to the control of various systems. This allows users of the system to interact without having to use any controls or equipment. This paper investigates the use of gesture recognition in order to select and transport audio tracks over an Ethernet AVB network to speaker endpoints. The research uses equipment that is commercially available and relatively cost efficient. The endpoints receive audio samples that are encapsulated within network packets and processes them. The audio tracks are mixed at the endpoints according to gain ratios that will change and be different for each endpoint.
- Full Text:
- Authors: Hedges, Mitchell , Foss, Richard
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426816 , vital:72393 , https://www.aes.org/e-lib/online/browse.cfm?elib=17540
- Description: Gesture recognition has become a preferred approach to the control of various systems. This allows users of the system to interact without having to use any controls or equipment. This paper investigates the use of gesture recognition in order to select and transport audio tracks over an Ethernet AVB network to speaker endpoints. The research uses equipment that is commercially available and relatively cost efficient. The endpoints receive audio samples that are encapsulated within network packets and processes them. The audio tracks are mixed at the endpoints according to gain ratios that will change and be different for each endpoint.
- Full Text:
Validation of an assessment tool for mental fatigue applied to rotational shift work
- Authors: Huysamen, Kirsten Christina
- Date: 2014
- Subjects: Mental fatigue , Shift systems , Performance , Motor ability , Memory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5154 , http://hdl.handle.net/10962/d1013551
- Description: Mental fatigue has been proven to be highly prominent during shift work, due to long, irregular working hours and disruption of the circadian rhythm. Measuring mental fatigue has been a challenge for many years, where commonly cognitive test tasks are used to assess mental fatigue. Moreover, these test tasks do not isolate where fatigue is occurring during human information processing. The human information processing system consists of four core stages, each of which requires numerous cognitive functions in order to process information. The Human Kinetics and Ergonomics Department at Rhodes University has developed six cognitive test tasks where each isolates a cognitive function: an accommodation test task, a visual detection test task, a reading test task, a memory test task, a tapping test task and a neural control test task. The cognitive functions include: eye accommodation, visual discrimination, visual pattern recognition, memory duration, motor programming and peripheral neural control. General task-related effect can also be examined for each of these cognitive test tasks which include choice reaction time, visual detection, reading performance, short-term memory, motor control and tracking performance. Additionally, a simple reaction time test task has been developed to analyse simple reaction time. This test task does not isolate a cognitive function. One or more parameters can be examined for each cognitive function and task-related effect. The first aim of this study was to validate numerous cognitive test tasks for mental fatigue in a simulated shift work laboratory setting. The second aim was to assess the validated cognitive test tasks in Phase 1 in a field-based rotational shift work setting. Parameters revealing sensitivity to mental fatigue would be validated for mental fatigue applied to rotational shift work and would be inserted into an assessment tool. In the laboratory setting, the seven cognitive test tasks were examined on four different types of shift work regimes. The first regime was a standard eight-hour shift work system, and the other three were non-conventional shift work regimes. Participants (n = 12 per regime) were required to complete one day shift followed by four night shifts, where testing occurred before and after each shift and four times within each shift. The cognitive test tasks revealing sensitivity to fatigue included: visual detection test task, reading test task, memory test task, tapping test task, neural control test task and simple reaction time test task. The testing of Phase 2 was conducted in three different companies, where each performed a different type of rotational shift work. The six cognitive test tasks validated for mental fatigue in Phase 1 were tested before and after work for each shift type within the rotational shift work system adopted by each company. Company A (n = 18) and Company B (n = 24) performed two-shift rotational shift work systems, where the shift length of Company A was 12-hours and the shift length of Company B was irregular hours. Company C (n = 21) performed an eight-hour three-shift rotational shift work system. Nine parameters revealed fatiguing effects and were inserted into the assessment tool, five of which provided information on a specific cognitive function: error rate for visual discrimination, processing time for visual pattern recognition, error rate for visual pattern recognition, impact of rehearsal time on memory recall rate for memory duration and the high-precision condition for motor programming time. The remaining four parameters provided information on general task-related effects: reading speed for reading performance, recall rate for short-term memory, reaction time for motor control and simple reaction time. Therefore, an assessment tool comprising nine parameters was validated for mental fatigue applied to rotational shift work, where five of the parameters were able to isolate exactly where fatigue was occurring during human information processing and the other four parameters were able to assess fatigue occurring throughout the human information processing chain.
- Full Text:
- Authors: Huysamen, Kirsten Christina
- Date: 2014
- Subjects: Mental fatigue , Shift systems , Performance , Motor ability , Memory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5154 , http://hdl.handle.net/10962/d1013551
- Description: Mental fatigue has been proven to be highly prominent during shift work, due to long, irregular working hours and disruption of the circadian rhythm. Measuring mental fatigue has been a challenge for many years, where commonly cognitive test tasks are used to assess mental fatigue. Moreover, these test tasks do not isolate where fatigue is occurring during human information processing. The human information processing system consists of four core stages, each of which requires numerous cognitive functions in order to process information. The Human Kinetics and Ergonomics Department at Rhodes University has developed six cognitive test tasks where each isolates a cognitive function: an accommodation test task, a visual detection test task, a reading test task, a memory test task, a tapping test task and a neural control test task. The cognitive functions include: eye accommodation, visual discrimination, visual pattern recognition, memory duration, motor programming and peripheral neural control. General task-related effect can also be examined for each of these cognitive test tasks which include choice reaction time, visual detection, reading performance, short-term memory, motor control and tracking performance. Additionally, a simple reaction time test task has been developed to analyse simple reaction time. This test task does not isolate a cognitive function. One or more parameters can be examined for each cognitive function and task-related effect. The first aim of this study was to validate numerous cognitive test tasks for mental fatigue in a simulated shift work laboratory setting. The second aim was to assess the validated cognitive test tasks in Phase 1 in a field-based rotational shift work setting. Parameters revealing sensitivity to mental fatigue would be validated for mental fatigue applied to rotational shift work and would be inserted into an assessment tool. In the laboratory setting, the seven cognitive test tasks were examined on four different types of shift work regimes. The first regime was a standard eight-hour shift work system, and the other three were non-conventional shift work regimes. Participants (n = 12 per regime) were required to complete one day shift followed by four night shifts, where testing occurred before and after each shift and four times within each shift. The cognitive test tasks revealing sensitivity to fatigue included: visual detection test task, reading test task, memory test task, tapping test task, neural control test task and simple reaction time test task. The testing of Phase 2 was conducted in three different companies, where each performed a different type of rotational shift work. The six cognitive test tasks validated for mental fatigue in Phase 1 were tested before and after work for each shift type within the rotational shift work system adopted by each company. Company A (n = 18) and Company B (n = 24) performed two-shift rotational shift work systems, where the shift length of Company A was 12-hours and the shift length of Company B was irregular hours. Company C (n = 21) performed an eight-hour three-shift rotational shift work system. Nine parameters revealed fatiguing effects and were inserted into the assessment tool, five of which provided information on a specific cognitive function: error rate for visual discrimination, processing time for visual pattern recognition, error rate for visual pattern recognition, impact of rehearsal time on memory recall rate for memory duration and the high-precision condition for motor programming time. The remaining four parameters provided information on general task-related effects: reading speed for reading performance, recall rate for short-term memory, reaction time for motor control and simple reaction time. Therefore, an assessment tool comprising nine parameters was validated for mental fatigue applied to rotational shift work, where five of the parameters were able to isolate exactly where fatigue was occurring during human information processing and the other four parameters were able to assess fatigue occurring throughout the human information processing chain.
- Full Text:
Valuation of banks in emerging markets: an exploratory study
- Authors: Sabilika, Keith
- Date: 2014
- Subjects: Banks and banking -- Valuation , Banks and banking -- Valuation -- Developing countries , Discounted cash flow , Capital assets pricing model , Capital -- Developing countries
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1200 , http://hdl.handle.net/10962/d1013057
- Description: Practitioners and academics in emerging markets are yet to agree on how best they can value companies in emerging markets. In contrast, academics and practitioners in developed markets seem to agree on mainstream valuation practices (Bruner, Eades, Harris and Haggins, 1998; Graham and Harvey, 2001). This study was therefore aimed at achieving such consensus with particular attention being paid to the emerging market banks. Emerging market banks are by no means small and are growing fast. Furthermore, these banks are currently involved in lots of cutting age economic activities such as mergers and acquisitions (M&A), joint ventures and strategic alliances which require sound valuation practices that are based on empirical evidence. The primary purpose of this research was to establish consensus of opinion among experts with regard to the valuation of banks in emerging markets. To achieve the purpose of this study the Delphi technique, which is a structured survey method that relies on a panel of experts to answer questionnaires in two or more Delphi rounds, was used to gather data and develop consensus among experts (Kalaian and Kasim, 2012). The main findings in this study pertain to aspects concerning the type of analysis considered by experts when analysing the performance of banks, how experts compare the discounted cash flow (DCF) approach to multiples valuation approach, the challenges encountered by experts when valuing banks in emerging markets, and how experts compute the cost of capital for banks in emerging markets. The main findings of this study can be summarised as follows: ∙ When analyzing the performance of banks, it is essential to conduct a bank-specific, industry and macroeconomic analysis; ∙ When estimating the future performance of banks, the time series analysis and an explicit forecast period of between 4-10 years may be used; ∙ When estimating the terminal value for banks in emerging markets, the perpetuity with growth is used; ∙ When computing the value for banks, the DCF valuation approach (equity DCF and DDM valuation models) are used as primary valuation methods and the relative valuation approach (P/E and P/BV ratio) are used as secondary valuation methods; ∙ The DCF valuation approach is considered as more accurate and popular when valuing banks in emerging markets; and ∙ When estimating the cost of equity, the capital asset pricing model (CAPM) is used.
- Full Text:
- Authors: Sabilika, Keith
- Date: 2014
- Subjects: Banks and banking -- Valuation , Banks and banking -- Valuation -- Developing countries , Discounted cash flow , Capital assets pricing model , Capital -- Developing countries
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1200 , http://hdl.handle.net/10962/d1013057
- Description: Practitioners and academics in emerging markets are yet to agree on how best they can value companies in emerging markets. In contrast, academics and practitioners in developed markets seem to agree on mainstream valuation practices (Bruner, Eades, Harris and Haggins, 1998; Graham and Harvey, 2001). This study was therefore aimed at achieving such consensus with particular attention being paid to the emerging market banks. Emerging market banks are by no means small and are growing fast. Furthermore, these banks are currently involved in lots of cutting age economic activities such as mergers and acquisitions (M&A), joint ventures and strategic alliances which require sound valuation practices that are based on empirical evidence. The primary purpose of this research was to establish consensus of opinion among experts with regard to the valuation of banks in emerging markets. To achieve the purpose of this study the Delphi technique, which is a structured survey method that relies on a panel of experts to answer questionnaires in two or more Delphi rounds, was used to gather data and develop consensus among experts (Kalaian and Kasim, 2012). The main findings in this study pertain to aspects concerning the type of analysis considered by experts when analysing the performance of banks, how experts compare the discounted cash flow (DCF) approach to multiples valuation approach, the challenges encountered by experts when valuing banks in emerging markets, and how experts compute the cost of capital for banks in emerging markets. The main findings of this study can be summarised as follows: ∙ When analyzing the performance of banks, it is essential to conduct a bank-specific, industry and macroeconomic analysis; ∙ When estimating the future performance of banks, the time series analysis and an explicit forecast period of between 4-10 years may be used; ∙ When estimating the terminal value for banks in emerging markets, the perpetuity with growth is used; ∙ When computing the value for banks, the DCF valuation approach (equity DCF and DDM valuation models) are used as primary valuation methods and the relative valuation approach (P/E and P/BV ratio) are used as secondary valuation methods; ∙ The DCF valuation approach is considered as more accurate and popular when valuing banks in emerging markets; and ∙ When estimating the cost of equity, the capital asset pricing model (CAPM) is used.
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Vice-Chancellor's 2014 Address to Graduation Ceremonies
- Authors: Badat, Saleem
- Date: 2014
- Language: English
- Type: text
- Identifier: vital:7868 , http://hdl.handle.net/10962/d1016417
- Full Text:
- Authors: Badat, Saleem
- Date: 2014
- Language: English
- Type: text
- Identifier: vital:7868 , http://hdl.handle.net/10962/d1016417
- Full Text:
Vice-Chancellor's 2014 Address to Graduation Ceremonies
- Authors: Badat, Saleem
- Date: 2014
- Language: English
- Type: text
- Identifier: vital:7869 , http://hdl.handle.net/10962/d1016418
- Full Text:
- Authors: Badat, Saleem
- Date: 2014
- Language: English
- Type: text
- Identifier: vital:7869 , http://hdl.handle.net/10962/d1016418
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Voltammetric investigation of complex growth media at a bare glassy carbon electrode: a case study of oxytetracycline
- Kruid, Jan, Fogel Ronen, Limson, Janice
- Authors: Kruid, Jan , Fogel Ronen , Limson, Janice
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431206 , vital:72753 , xlink:href="https://doi.org/10.1016/j.electacta.2013.08.188"
- Description: Reports regarding the voltammetric properties of microbiological growth media are scarce in the literature and limited focus has been placed towards the application of electroanalysis for analyte monitoring in these complex media. This work aims to investigate the viability of voltammetry as a quantification method for analytes in microbiological growth media, using oxytetracycline (OTC) as a model analyte. Analysis of both commercially available and laboratory prepared growth media indicated the presence of interfering media components which produced anodic peaks at potentials ranging from ∼+0.85 V to ∼+1.30 V (vs. Ag/AgCl) under acidic conditions and ∼+0.62 V to ∼+1.35 V (vs. Ag/AgCl) under neutral pH. These peaks were identified as originating from proteinaceous components of growth media and correlated to the presence of peptone, malt extract and yeast extract. Electrochemical impedance spectroscopy demonstrated significant increases in the charge transfer resistance for Fe(CN)63−/4− redox probes at glassy carbon electrodes in the presence of peptone-comprised media (130.3 Ω) compared to media-free buffer (50.4 Ω). Adsorption of the aforementioned media components to the electrode surface thus contributes to analytical interference through faradaic and non-faradaic processes. By adapting the growth media for analyte detection purposes, this study proves the feasibility of detecting OTC, as well as the use of dilution of the media to further decrease the interferent effects of growth media. A 50-fold dilution of the media provided a 96.7% recovery of the OTC peak current at 20 μM concentration. The empirical detection limit of OTC in 50-fold diluted media was determined to be 0.5 μM, which makes it applicable to current industrial OTC fermentation processes.
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- Authors: Kruid, Jan , Fogel Ronen , Limson, Janice
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431206 , vital:72753 , xlink:href="https://doi.org/10.1016/j.electacta.2013.08.188"
- Description: Reports regarding the voltammetric properties of microbiological growth media are scarce in the literature and limited focus has been placed towards the application of electroanalysis for analyte monitoring in these complex media. This work aims to investigate the viability of voltammetry as a quantification method for analytes in microbiological growth media, using oxytetracycline (OTC) as a model analyte. Analysis of both commercially available and laboratory prepared growth media indicated the presence of interfering media components which produced anodic peaks at potentials ranging from ∼+0.85 V to ∼+1.30 V (vs. Ag/AgCl) under acidic conditions and ∼+0.62 V to ∼+1.35 V (vs. Ag/AgCl) under neutral pH. These peaks were identified as originating from proteinaceous components of growth media and correlated to the presence of peptone, malt extract and yeast extract. Electrochemical impedance spectroscopy demonstrated significant increases in the charge transfer resistance for Fe(CN)63−/4− redox probes at glassy carbon electrodes in the presence of peptone-comprised media (130.3 Ω) compared to media-free buffer (50.4 Ω). Adsorption of the aforementioned media components to the electrode surface thus contributes to analytical interference through faradaic and non-faradaic processes. By adapting the growth media for analyte detection purposes, this study proves the feasibility of detecting OTC, as well as the use of dilution of the media to further decrease the interferent effects of growth media. A 50-fold dilution of the media provided a 96.7% recovery of the OTC peak current at 20 μM concentration. The empirical detection limit of OTC in 50-fold diluted media was determined to be 0.5 μM, which makes it applicable to current industrial OTC fermentation processes.
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Voluntary disclosure programmes and tax amnesties: an international appraisal
- Authors: Jaramba, Toddy
- Date: 2014
- Subjects: Tax amnesty -- South Africa , Tax evasion -- South Africa , Investments, Foreign -- Taxation -- South Africa , Tax collection -- South Africa , Tax administration and procedure -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:911 , http://hdl.handle.net/10962/d1015666
- Description: Tax amnesties are government programs that typically allow a short period of time for tax evaders to voluntarily repay previously evaded taxes without being subject to penalties and prosecution that discovery of such tax evasion normally brings. Tax amnesties differ widely in terms of coverage, tax types, and incentives offered. A state’s Voluntary Disclosure Programme is another avenue available to taxpayers to assist them in resolving their state tax delinquencies. This programme is an on-going programme as compared to a tax amnesty, which is there for a limited time period only. The main goal of the research was to describe the tax amnesty and the voluntary disclosure programmes in South Africa and to assess their advantages and disadvantages. This thesis also discussed another form of voluntary disclosure programme, referred to as an Offshore Voluntary Disclosure Programme, which allows taxpayers with unreported foreign bank accounts, and presumably unreported foreign income, to voluntarily disclose their affairs. The study found that, due to tax amnesties, Government raises more tax revenue not only in the short run from collecting overdue taxes but also by bringing former non-filers back into the tax system for the long run. It was also found that, initially short-run revenue brought in from overdue taxes will be positive for the first amnesty and then decline each time the amnesty is offered repeatedly. The reason for the decline in revenue might be that tax amnesties provide incentives for otherwise honest taxpayers to start evading taxes because they will anticipate the offering of future amnesties, thereby weakening tax compliance. The costs associated with amnesty programmes include negative long run revenue impact and also that amnesty programmes reduce compliance by taxpayers in the long-run. In South Africa tax amnesties, especially the voluntary disclosure programme, are likely to be successful since they will increase the revenue yield and also bring non-filers back on the tax rolls.
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- Authors: Jaramba, Toddy
- Date: 2014
- Subjects: Tax amnesty -- South Africa , Tax evasion -- South Africa , Investments, Foreign -- Taxation -- South Africa , Tax collection -- South Africa , Tax administration and procedure -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:911 , http://hdl.handle.net/10962/d1015666
- Description: Tax amnesties are government programs that typically allow a short period of time for tax evaders to voluntarily repay previously evaded taxes without being subject to penalties and prosecution that discovery of such tax evasion normally brings. Tax amnesties differ widely in terms of coverage, tax types, and incentives offered. A state’s Voluntary Disclosure Programme is another avenue available to taxpayers to assist them in resolving their state tax delinquencies. This programme is an on-going programme as compared to a tax amnesty, which is there for a limited time period only. The main goal of the research was to describe the tax amnesty and the voluntary disclosure programmes in South Africa and to assess their advantages and disadvantages. This thesis also discussed another form of voluntary disclosure programme, referred to as an Offshore Voluntary Disclosure Programme, which allows taxpayers with unreported foreign bank accounts, and presumably unreported foreign income, to voluntarily disclose their affairs. The study found that, due to tax amnesties, Government raises more tax revenue not only in the short run from collecting overdue taxes but also by bringing former non-filers back into the tax system for the long run. It was also found that, initially short-run revenue brought in from overdue taxes will be positive for the first amnesty and then decline each time the amnesty is offered repeatedly. The reason for the decline in revenue might be that tax amnesties provide incentives for otherwise honest taxpayers to start evading taxes because they will anticipate the offering of future amnesties, thereby weakening tax compliance. The costs associated with amnesty programmes include negative long run revenue impact and also that amnesty programmes reduce compliance by taxpayers in the long-run. In South Africa tax amnesties, especially the voluntary disclosure programme, are likely to be successful since they will increase the revenue yield and also bring non-filers back on the tax rolls.
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