The freshwater dinoflagellate species, Ceratium hirundinella (C. hirundinella) possesses unique characteristics, such as a thecal-plate cell covering of cellulose, spines and flagella. Unlike most other algae and cyanobacteria, C. hirundinella cells are relatively large in size (up to 450 μm in length and 50 μm in width). These unique characteristics (e.g. cell covering and flagella) and adaptations (e.g. spines) give the dinoflagellate cells the ability to reduce their sinking rate from the euphotic zone and to migrate easily through the water column. When source water contains high concentrations of C. hirundinella cells, water treatment problems and poor aesthetic water quality can be expected. These water treatment problems may include 1) the disruption of coagulation and flocculation, 2) clogging of sand filters and 3) taste and odour problems when cells penetrate into the final water. In Chapter 9 of this study, a list of operational guidelines (including alert levels) and recommendations to assist managers and operators of plants when C. hirundinella cells are causing water treatment problems. During events of high C. hirundinella concentrations in source water, managers and operators of conventional water treatment plants need strategies to optimize coagulants and unit processes. Thus when source water contains motile nuisance algae, such as C. hirundinella, in moderate or abundant quantities, it is advisable to conduct jar stirring test experiments using both turbidity and total photosynthetic pigment (or chlorophyll-a) analyses as indicators of appropriate coagulant choice and dosages. The aims of this study are summarized as follows:  To optimize coagulants and conventional water treatment processes by implementing relevant algal removal strategies and indicators during jar stirring test experiments,  To investigate the changes in surface charge (known as zeta potential) on C. hirundinella cells before and after adding coagulants as part of the treatment processes,  To investigate the physical and chemical impacts on the morphology of C. hirundinella cells after coagulation, flocculation and sedimentation,  To identify organic compounds that may be responsible for taste and odour problems associated with C. hirundinella,  To investigate the efficiency of pre-chlorination on the removal C. hirundinella cells when dosing various coagulants, and  Give recommendations and operational guidelines relevant for a conventional water treatment plant to improve C. hirundinella removal A combined water treatment system (Phipps and Bird Model), consisting of a six paddle jar test apparatus and six sand filter columns, was used to simulate conventional processes (coagulation, flocculation, sedimentation and rapid sand filtration). Source water samples containing relatively high C. hirundinella concentrations (> 500 cell/mℓ) were collected from Benoni Lake (26º10’50.40’’S; 28º17’50.11’’ E) in plastic containers and stored as a homogenous sample in a 200 litre container under laboratory conditions (± 22 °C). Samples were collected from the source water as well as after sedimentation (from the supernatant or sludge) to determine turbidity, total photosynthetic pigment analyses (chlorophyll) and for phytoplankton analyses. Flocs (containing C. hirundinella cells) were collected from the sludge or sediment for scanning electron microscopy investigations and to perform zeta potential analyses. Concentrated C. hirundinella samples were frozen at -80 °C according to the proposed sampling protocol for organic compound analyses. Results obtained from this study proved that using the relevant indicators to determine the appropriate coagulant dosages during jar stirring tests may generally improve the removal of problem-causing algae, such as C. hirundinella cells. Improved algal removal efficiencies will subsequently ensure final water with good aesthetic quality. The surface charge (zeta potential) on C. hirundinella cells can be used to evaluate the best coagulation conditions within an operating window of -10 mV to +3 mV when dosing various coagulants. Scanning electron microscopy investigations revealed major damaging effects to C. hirundinella cells when dosing high Ca(OH)2 concentrations. However, when dosing lower Ca(OH)2 concentrations, in combination with organic polymer, better C. hirundinella cell removal efficiencies with less damaging effects to cells was observed. This study also indicated that the pre-chlorination, without causing cell lyses, can be applied to render the highly motile cells immobile which will subsequently assist the coagulation unit process. The aesthetic quality (e.g. tastes and odours) of drinking water may be influenced when C. hirundinella cells release organic material into the water as a result of cell lyses. Organic compounds, such as fatty acids and dicarboxylic acids can lead to taste and odour problems which associate with the presence of C. hirundinella. Organic compounds also serve as precursors for the formation of harmful chlorine by-products formed during chlorination. / PhD (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Vegetation establishment is one of the major rehabilitation methods that are used to stabilize, cover, to minimize, mitigate or remove the contaminants from tailings storage facilities (TSF’s). Phytostabilization is a useful mechanism by which plants limit the contamination of natural systems with toxic elements. For successful occurrence of phytostabilization on mine tailings, it is vital to establish plant species that can survive the hostile conditions of the substrate. Major problems encountered with vegetation covers is the lack of natural soil properties e.g. soil structure, organic carbon and also hostile chemical conditions. Only a few species are tolerant to the different negative properties of the tailings. The main aim of this project is to identify plant species that can be used for vegetative rehabilitation of nine different types of tailings material including gypsum, gold, platinum, kimberlite, coal, fluorspar and andalusite tailings. The ability of 28 different plant species to survive in the tailings was assessed by statistically calculating the growth potential of the species and summarizing the data in graphs and an index table that calculates a specific merit value for each of the tailings-species combinations. The various plant stress factors that the species exhibited were also documented. Finally, the results were correlated with a soil physical and -chemical baseline study of the tailings to provide insight into successes and failures of certain species. The final results identified various successful tailings-species combinations, as well as failures. The index table proved to be a useful tool to identify suitable species for establishment on various tailings. The baseline study of the different tailings could be used to explain why certain species could be established successfully, as well as the reason why some species did not survive. / M (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

The freshwater dinoflagellate species, Ceratium hirundinella (C. hirundinella) possesses unique characteristics, such as a thecal-plate cell covering of cellulose, spines and flagella. Unlike most other algae and cyanobacteria, C. hirundinella cells are relatively large in size (up to 450 μm in length and 50 μm in width). These unique characteristics (e.g. cell covering and flagella) and adaptations (e.g. spines) give the dinoflagellate cells the ability to reduce their sinking rate from the euphotic zone and to migrate easily through the water column. When source water contains high concentrations of C. hirundinella cells, water treatment problems and poor aesthetic water quality can be expected. These water treatment problems may include 1) the disruption of coagulation and flocculation, 2) clogging of sand filters and 3) taste and odour problems when cells penetrate into the final water. In Chapter 9 of this study, a list of operational guidelines (including alert levels) and recommendations to assist managers and operators of plants when C. hirundinella cells are causing water treatment problems. During events of high C. hirundinella concentrations in source water, managers and operators of conventional water treatment plants need strategies to optimize coagulants and unit processes. Thus when source water contains motile nuisance algae, such as C. hirundinella, in moderate or abundant quantities, it is advisable to conduct jar stirring test experiments using both turbidity and total photosynthetic pigment (or chlorophyll-a) analyses as indicators of appropriate coagulant choice and dosages. The aims of this study are summarized as follows:  To optimize coagulants and conventional water treatment processes by implementing relevant algal removal strategies and indicators during jar stirring test experiments,  To investigate the changes in surface charge (known as zeta potential) on C. hirundinella cells before and after adding coagulants as part of the treatment processes,  To investigate the physical and chemical impacts on the morphology of C. hirundinella cells after coagulation, flocculation and sedimentation,  To identify organic compounds that may be responsible for taste and odour problems associated with C. hirundinella,  To investigate the efficiency of pre-chlorination on the removal C. hirundinella cells when dosing various coagulants, and  Give recommendations and operational guidelines relevant for a conventional water treatment plant to improve C. hirundinella removal A combined water treatment system (Phipps and Bird Model), consisting of a six paddle jar test apparatus and six sand filter columns, was used to simulate conventional processes (coagulation, flocculation, sedimentation and rapid sand filtration). Source water samples containing relatively high C. hirundinella concentrations (> 500 cell/mℓ) were collected from Benoni Lake (26º10’50.40’’S; 28º17’50.11’’ E) in plastic containers and stored as a homogenous sample in a 200 litre container under laboratory conditions (± 22 °C). Samples were collected from the source water as well as after sedimentation (from the supernatant or sludge) to determine turbidity, total photosynthetic pigment analyses (chlorophyll) and for phytoplankton analyses. Flocs (containing C. hirundinella cells) were collected from the sludge or sediment for scanning electron microscopy investigations and to perform zeta potential analyses. Concentrated C. hirundinella samples were frozen at -80 °C according to the proposed sampling protocol for organic compound analyses. Results obtained from this study proved that using the relevant indicators to determine the appropriate coagulant dosages during jar stirring tests may generally improve the removal of problem-causing algae, such as C. hirundinella cells. Improved algal removal efficiencies will subsequently ensure final water with good aesthetic quality. The surface charge (zeta potential) on C. hirundinella cells can be used to evaluate the best coagulation conditions within an operating window of -10 mV to +3 mV when dosing various coagulants. Scanning electron microscopy investigations revealed major damaging effects to C. hirundinella cells when dosing high Ca(OH)2 concentrations. However, when dosing lower Ca(OH)2 concentrations, in combination with organic polymer, better C. hirundinella cell removal efficiencies with less damaging effects to cells was observed. This study also indicated that the pre-chlorination, without causing cell lyses, can be applied to render the highly motile cells immobile which will subsequently assist the coagulation unit process. The aesthetic quality (e.g. tastes and odours) of drinking water may be influenced when C. hirundinella cells release organic material into the water as a result of cell lyses. Organic compounds, such as fatty acids and dicarboxylic acids can lead to taste and odour problems which associate with the presence of C. hirundinella. Organic compounds also serve as precursors for the formation of harmful chlorine by-products formed during chlorination. / PhD (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Vegetation establishment is one of the major rehabilitation methods that are used to stabilize, cover, to minimize, mitigate or remove the contaminants from tailings storage facilities (TSF’s). Phytostabilization is a useful mechanism by which plants limit the contamination of natural systems with toxic elements. For successful occurrence of phytostabilization on mine tailings, it is vital to establish plant species that can survive the hostile conditions of the substrate. Major problems encountered with vegetation covers is the lack of natural soil properties e.g. soil structure, organic carbon and also hostile chemical conditions. Only a few species are tolerant to the different negative properties of the tailings. The main aim of this project is to identify plant species that can be used for vegetative rehabilitation of nine different types of tailings material including gypsum, gold, platinum, kimberlite, coal, fluorspar and andalusite tailings. The ability of 28 different plant species to survive in the tailings was assessed by statistically calculating the growth potential of the species and summarizing the data in graphs and an index table that calculates a specific merit value for each of the tailings-species combinations. The various plant stress factors that the species exhibited were also documented. Finally, the results were correlated with a soil physical and -chemical baseline study of the tailings to provide insight into successes and failures of certain species. The final results identified various successful tailings-species combinations, as well as failures. The index table proved to be a useful tool to identify suitable species for establishment on various tailings. The baseline study of the different tailings could be used to explain why certain species could be established successfully, as well as the reason why some species did not survive. / M (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Please read the abstract in the section 00front of this document / Thesis (PhD)--University of Pretoria, 2010. / Immunology / unrestricted

The South African education system has experienced a paradigm shift from content-based education towards an outcomes-based education. The focus of outcomes-based education is a learner-centred approach. The criteria that learners should adhere to at the end of their school career are that they should be productive, successful lifelong learners. To achieve these criteria, learners should be able to maximise their own potential. The world of work requires learners to easily adapt and function effectively in groups and to have the ability to achieve the set criteria. This means that the world of work demands productive, critical, independent learners who are able to express themselves and communicate effectively within social situations. The question that arises is whether learners within the South African context have the ability to create opportunities to claim ownership and take responsibility for their own learning. The focus of this research is therefore on the role of maximising human potential as determined by the need of South African learners to be empowered and well prepared for the demands of the world of work. The literature pertaining to the nature, phenomenon and process of maximising of human potential is briefly examined and the fundamentals are identified. Maximising of human potential is contextualised as a component of the educational phenomenon. An observation study of two classgroups consisting of grade 8 and grade 10 learners respectively from the same school was undertaken in order to identify and determine whether learners within a realistic, diverse school setting are capable of maximising their own potential. Profiles were compiled to underline the socio-economic background of each learner and to serve as a mechanism to indicate and underline diversity in the classroom. Interviews with teachers and learners served as cross-validation of these results. The results revealed that learners from the school were demotivated with regard to maximising their potential. As a qualitative study, the final results indicated trends that may be generalised to similar classrooms. The phenomenon of maximising of human potential is based on the principle of outcomes-based education and should be the focus of learning in every classroom. Guidelines and models for a facilitator training programme in maximising human potential are suggested. The findings of the study indicate that by virtue of the fact that the teaching and learning process is to be approached from a new angle, teachers first need to have a changed perspective or execute a philosophical leap before they are able to maximise the potential of learners in the classroom. Recommendations for the future include, amongst others, that the teacher should be seen as a facilitator of opportunities for learner contributions; that because of the new and exciting demands made on the teacher by this approach, knowledge and expertise regarding maximising of human potential as didactic practice should be made available; that a longitudinal observation study of teachers who received such training, and their pupils, is undertaken as a follow-up study in order to evaluate the results of the training; and that further research is undertaken locally as well as in other countries where the maximising of human potential in language as learning phenomenon is already being practiced. / Dissertation (MEd (Curriculum Studies))--University of Pretoria, 2006. / Curriculum Studies / unrestricted

Al hoe meer organisasies in Suid-Afrika gaan tans deur 'n herstruktureringsfase wat meebring dat die totale werksmilieu verander. Die werknemer verkeer onder druk om aan die nuwe eise in die wereld van werk te voldoen. Druk om te presteer en werksuitset te !ewer mag disfunksionele stres en antler psigiese probleme meebring. Organisasies speel 'n belangrike rol in die dinamiese groeiproses van die individuele werknemer en raak toenemend bewus van die werknemer se fisiese en psigiese gesondheid. Talle organisasies het reeds korporatiewe gimnasiums opgerig en sommige bied subsidiering van lidmaatskap aan gesondheidsklubs aan hul werknemers. Sekere mediese skemas begin self gesondheidsplanne ontwerp met behulp van gesondheidsklubs om die gesondheid van die werknemer te bevorder. / M.A. (Bedryfsielkunde)

Al hoe meer organisasies in Suid-Afrika gaan tans deur 'n herstruktureringsfase wat meebring dat die totale werksmilieu verander. Die werknemer verkeer onder druk om aan die nuwe eise in die wereld van werk te voldoen. Druk om te presteer en werksuitset te !ewer mag disfunksionele stres en antler psigiese probleme meebring. Organisasies speel 'n belangrike rol in die dinamiese groeiproses van die individuele werknemer en raak toenemend bewus van die werknemer se fisiese en psigiese gesondheid. Talle organisasies het reeds korporatiewe gimnasiums opgerig en sommige bied subsidiering van lidmaatskap aan gesondheidsklubs aan hul werknemers. Sekere mediese skemas begin self gesondheidsplanne ontwerp met behulp van gesondheidsklubs om die gesondheid van die werknemer te bevorder. / M.A. (Bedryfsielkunde)

Summaries in English and Afrikaans / The second fully democratic election in South Africa is scheduled to take place in May 1999. In the five years since the first election, it appears that very little attention has been paid to the political literacy of the electorate in general, and the youth in particular. The purpose of this study was to establish adolescents' level of political knowledge and whether they are able to think critically about political issues or not. The first part of the literature study which was concerned with critical thinking revealed that the major aspects of critical thinking are: deductive reasoning, inductive inference, recognition of assumptions, credibility, and problem solving. The second part of the literature study was an analysis of which factors may play a role in the development of critical thinking of an adolescent. with particular reference to a political context. The third part was an examination of important current political and social issues. These were: the new Constitution. Truth and Reconciliation Commission, housing, land redistribution, education, labour, health, crime, political violence, environment, and the next election. A reliable measuring instrument was developed in order to measure adolescents' knowledge of political issues, and their ability to think critically about these issues. The results of the empirical study revealed that intellectual potential and academic achievement were significantly related to critical thinking ability, while gender, environment, and personality appeared not to play a role. There was a significant correlation between political knowledge and critical thinking in a political context, implying that critical thinking is subject-specific. Cultural background also played a significant role in critical thinking in a political context. In terms of political knowledge, boys were found to be at a significantly higher level than girls. The subjects from urban areas were also at a significantly higher level than those from rural areas. There was also a positive correlation between intellectual potential, academic achievement, and political knowledge. Finally, some recommendations for improving the levels of political knowledge and critical thinking abilities with regard to political issues of South African adolescents were given. / Die tweede ten valle demokratiese verkiesing in Suid-Afrika is geskeduleer om in Mei 1999 plaas te vind. In die vyf jaar sedert die vorige verkiesing is baie min aandag gegee aan die politieke geletterdheid van die verkiesingspubliek in die algemeen en die jeug in besonder. Die doel van hierdie studie was om adolessente se vlak van politieke kennis te bepaal en om vas te stel of hulle in staat is om krities oar politieke kwessies na te dink. Die eerste deel van die literatuurstudie wat verband hou met kritiese denke het uitgewys dat die hoofaspekte van kritiese denke die volgende is: deduktiewe redenering, induktiewe inferensies, herkenning van aannames, geloofwaardigheid en probleemoplossing. Die tweede deel van die literatuurstudie behels 'n analise van die faktore wat 'n rol kan speel in die ontwikkeling van die kritiese denke van die adolessent, met spesifieke verwysing na 'n politieke konteks. Die derde deel is 'n ondersoek na belangrike teenswoordige politieke en sosiale kwessies. Hierdie kwessies sluit in: die nuwe Grondwet, die Waarheids- en Versoeningskommissie, behuising, herverdeling van grand, opvoeding, arbeid, gesondheid, misdaad, politieke geweld, die omgewing en die volgende verkiesing. 'n Betroubare meetinstrument om adolessente se kennis van politieke kwessies asook hul vermoe om krities daaroor na te dink, is ontwikkel. Die resultate van die empiriese ondersoek het aangetoon dat intellektuele potensiaal en akademiese prestasie betekenisvol verband hou met kritiese denkvermoe, terwyl geslag, omgewing en persoonlikheid klaarblyklik nie 'n rol speel nie. Daar is ook 'n betekenisvolle korrelasie tussen politieke kennis en kritiese denke in 'n politieke konteks wat impliseer dat kritiese denke vakspesifiek is. Kulturele agtergrond speel ook 'n betekenisvolle rol in kritiese denke in 'n politieke konteks. Ten opsigte van politieke kennis is daar bevind dat seuns op 'n betekenisvolle hoer vlak is as dogters. Respondente uit stedelike gebiede is oak op 'n betekenisvolle hoer vlak as diegene uit plattelandse gebiede. Oaar is oak 'n betekenisvolle korrelasie tussen intellektuele potensiaal, akademiese prestasie en politieke kennis. Ten slotte is aanbevelings gemaak om die vlakke van politieke kennis en kritiese denkvermoens met betrekking tot politieke aangeleenthede by Suid-Afrikaanse adolessente te verbeter. / Psychology of Education / D. Ed. (Psychology of Education)

Summaries in English and Afrikaans / The second fully democratic election in South Africa is scheduled to take place in May 1999. In the five years since the first election, it appears that very little attention has been paid to the political literacy of the electorate in general, and the youth in particular. The purpose of this study was to establish adolescents' level of political knowledge and whether they are able to think critically about political issues or not. The first part of the literature study which was concerned with critical thinking revealed that the major aspects of critical thinking are: deductive reasoning, inductive inference, recognition of assumptions, credibility, and problem solving. The second part of the literature study was an analysis of which factors may play a role in the development of critical thinking of an adolescent. with particular reference to a political context. The third part was an examination of important current political and social issues. These were: the new Constitution. Truth and Reconciliation Commission, housing, land redistribution, education, labour, health, crime, political violence, environment, and the next election. A reliable measuring instrument was developed in order to measure adolescents' knowledge of political issues, and their ability to think critically about these issues. The results of the empirical study revealed that intellectual potential and academic achievement were significantly related to critical thinking ability, while gender, environment, and personality appeared not to play a role. There was a significant correlation between political knowledge and critical thinking in a political context, implying that critical thinking is subject-specific. Cultural background also played a significant role in critical thinking in a political context. In terms of political knowledge, boys were found to be at a significantly higher level than girls. The subjects from urban areas were also at a significantly higher level than those from rural areas. There was also a positive correlation between intellectual potential, academic achievement, and political knowledge. Finally, some recommendations for improving the levels of political knowledge and critical thinking abilities with regard to political issues of South African adolescents were given. / Die tweede ten valle demokratiese verkiesing in Suid-Afrika is geskeduleer om in Mei 1999 plaas te vind. In die vyf jaar sedert die vorige verkiesing is baie min aandag gegee aan die politieke geletterdheid van die verkiesingspubliek in die algemeen en die jeug in besonder. Die doel van hierdie studie was om adolessente se vlak van politieke kennis te bepaal en om vas te stel of hulle in staat is om krities oar politieke kwessies na te dink. Die eerste deel van die literatuurstudie wat verband hou met kritiese denke het uitgewys dat die hoofaspekte van kritiese denke die volgende is: deduktiewe redenering, induktiewe inferensies, herkenning van aannames, geloofwaardigheid en probleemoplossing. Die tweede deel van die literatuurstudie behels 'n analise van die faktore wat 'n rol kan speel in die ontwikkeling van die kritiese denke van die adolessent, met spesifieke verwysing na 'n politieke konteks. Die derde deel is 'n ondersoek na belangrike teenswoordige politieke en sosiale kwessies. Hierdie kwessies sluit in: die nuwe Grondwet, die Waarheids- en Versoeningskommissie, behuising, herverdeling van grand, opvoeding, arbeid, gesondheid, misdaad, politieke geweld, die omgewing en die volgende verkiesing. 'n Betroubare meetinstrument om adolessente se kennis van politieke kwessies asook hul vermoe om krities daaroor na te dink, is ontwikkel. Die resultate van die empiriese ondersoek het aangetoon dat intellektuele potensiaal en akademiese prestasie betekenisvol verband hou met kritiese denkvermoe, terwyl geslag, omgewing en persoonlikheid klaarblyklik nie 'n rol speel nie. Daar is ook 'n betekenisvolle korrelasie tussen politieke kennis en kritiese denke in 'n politieke konteks wat impliseer dat kritiese denke vakspesifiek is. Kulturele agtergrond speel ook 'n betekenisvolle rol in kritiese denke in 'n politieke konteks. Ten opsigte van politieke kennis is daar bevind dat seuns op 'n betekenisvolle hoer vlak is as dogters. Respondente uit stedelike gebiede is oak op 'n betekenisvolle hoer vlak as diegene uit plattelandse gebiede. Oaar is oak 'n betekenisvolle korrelasie tussen intellektuele potensiaal, akademiese prestasie en politieke kennis. Ten slotte is aanbevelings gemaak om die vlakke van politieke kennis en kritiese denkvermoens met betrekking tot politieke aangeleenthede by Suid-Afrikaanse adolessente te verbeter. / Psychology of Education / D. Ed. (Psychology of Education)