Interactions between three biological control agents of water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae) in South Africa
- Authors: Petela, Nomvume
- Date: 2018
- Subjects: Water hyacinth -- South Africa , Water hyacinth -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Curculionidae , Delphacidae , Miridae , Neochetina eichhorniae Warner , Megamelus scutellaris Berg , Eccritotarsus eichhorniae Henry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60676 , vital:27814
- Description: Water hyacinth, Eichhomia crassipes (Mart.) Solms (Pontederiaceae) is a free-floating perennial weed that is regarded as the worst aquatic weed in the world because of its negative impacts on aquatic ecosystems. It is native to the Amazon Basin of South America, but since the late 1800s has spread throughout the world. The first record of the weed in South Africa was noted in 1908 on the Cape Flats and in KwaZulu-Natal, but it is now dispersed throughout the country. Mechanical and chemical control methods have been used against the weed, but biological control is considered the most cost-effective, sustainable and environmentally friendly intervention. Currently, nine biological control agents have been released against water hyacinth in South Africa, and Neochetina eichhorniae Warner (Coleoptera: Curculionidae) is used most widely to control it. However, in some sites, water hyacinth mats have still not been brought under control because of eutrophic waters and cool temperatures. It was therefore necessary to release new biological control agents to complement the impact of N. eichhorniae. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released in 2013, but little is known about how it interacts with other agents already present in South Africa. It is likely to compete with the established biological control agent, Eccritotarsus eichhorniae Henry (Heteroptera: Miridae), because they are both sap suckers. On the other hand, N. eichhorniae is the most widespread and thus the most important biological control agent for water hyacinth. The aim of this study, then, was to determine the interactions between the two sap-sucking agents in South Africa that presumably occupy similar niches on the plant, and the interaction between M. scutellerais and N. eichhorniae, the most widely distributed and abundant agent in South Africa. Three experiments were conducted at the Waainek Research Facility at Rhodes University, Grahamstown, Eastern Cape, South Africa. Plants were grown for two weeks and insect species were inoculated singly or in combination. Water hyacinth, plant growth parameters and insect parameters were measured every 14 days for a period of 12 weeks. The results of the study showed that feeding by either E. eichhorniae or M. scutellaris had no effect on the feeding of the other agent. Both agents reduced all the measured plant growth parameters equally, either singly or in combination (i.e. E. eichhorniae or M. scutellaris alone or together). The interaction between the two agents appears neutral and agents are likely to complement each other in the field. Prior feeding by E. eichhorniae or M. scutellaris on water hyacinth did not affect the subsequent feeding by either agent. Megamelus scutellaris prefers healthy fresh water hyacinth plants. In addition, planthoppers performed best in combination with the weevil, especially on plants with new weevil feeding scars. The results of the study showed that M. scutellaris is compatible with other biological control agents of water hyacinth that are already established in South Africa. Therefore, the introduction of M. scutellaris may enhance the biological control of water hyacinth in South Africa.
- Full Text:
- Date Issued: 2018
Interrogating teacher leadership development through a formative intervention: a case study in a rural Secondary School in northern Namibia
- Authors: Iyambo, David Kandiwapa
- Date: 2018
- Subjects: Educational leadership -- Namibia , School management and organization -- Namibia , Teachers -- Training of -- Namibia , Cultural Historical Activity Theory
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/61547 , vital:28035
- Description: The Namibian education system has undergone major policy shifts from a ‘top-down’ hierarchical leadership practice to a more shared and democratic form of leadership in schools. These policies compel principals and school management team members to involve level-one teachers in decision-making and other leadership roles within their schools and beyond. However, to this end, the goals envisaged by policies for teachers to participate in, and contribute to the overall school leadership activities and decision-making have not been fully realised. This was due to the inherent hierarchy of the ‘top-down’ system and autocratic leadership style which remains powerful within the current school practice. Against this backdrop, this study interrogated how teacher leadership can be developed in a rural Secondary School in northern Namibia. The underlying cultural-historical conditions that promoted or constrained teacher leadership development were surfaced. Opportunities for changes in leadership practices through a formative intervention were developed. Cultural Historical Activity Theory (CHAT) was utilised as a theoretical and analytical framework in this study together with Grant’s Model of Teacher Leadership (2006; 2008; 2010). Five level-one teachers, two school management members and a school board chairperson were selected as research participants by means of a purposive sampling method. Furthermore, the study used document analysis, semi-structured interviews, questionnaires and change laboratory workshops as main tools for data generation. The findings revealed that participants understood the concept of teacher leadership differently and that teachers in the case study school were leading in all four zones of teacher leadership model (Grant, 2006; 2008; 2012) although their roles differed. However, the study also found that teacher leadership development was mostly intensified by managerial structures. It appeared from the findings of this study that conditions such as the role of the school management team (SMT) members in promoting teacher leadership development, a supportive organisational culture, and provision of learning support amongst staff members through the attendance of workshops emerged as factors promoting the development of teachers as leaders. The study also revealed that there were many cultural and historical tensions that constrained the practice of teacher leadership development in school. Thus, the study argues that limited leadership training and an inherent ‘top-down’ hierarchical style of leadership was the main underlying systemic causes that constrained teachers to be developed as leaders. Through the change laboratory workshops, the findings suggested that there was a need for continuous professional development initiatives and leadership training, as alternative way for the realisation of teacher leadership development. Finally, a recommendation that leadership aspects should be constituted in pre-and in-service professional development training as an ongoing practice is made.
- Full Text:
- Date Issued: 2018
Investigating combinations of feature extraction and classification for improved image-based multimodal biometric systems at the feature level
- Authors: Brown, Dane
- Date: 2018
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63470 , vital:28414
- Description: Multimodal biometrics has become a popular means of overcoming the limitations of unimodal biometric systems. However, the rich information particular to the feature level is of a complex nature and leveraging its potential without overfitting a classifier is not well studied. This research investigates feature-classifier combinations on the fingerprint, face, palmprint, and iris modalities to effectively fuse their feature vectors for a complementary result. The effects of different feature-classifier combinations are thus isolated to identify novel or improved algorithms. A new face segmentation algorithm is shown to increase consistency in nominal and extreme scenarios. Moreover, two novel feature extraction techniques demonstrate better adaptation to dynamic lighting conditions, while reducing feature dimensionality to the benefit of classifiers. A comprehensive set of unimodal experiments are carried out to evaluate both verification and identification performance on a variety of datasets using four classifiers, namely Eigen, Fisher, Local Binary Pattern Histogram and linear Support Vector Machine on various feature extraction methods. The recognition performance of the proposed algorithms are shown to outperform the vast majority of related studies, when using the same dataset under the same test conditions. In the unimodal comparisons presented, the proposed approaches outperform existing systems even when given a handicap such as fewer training samples or data with a greater number of classes. A separate comprehensive set of experiments on feature fusion show that combining modality data provides a substantial increase in accuracy, with only a few exceptions that occur when differences in the image data quality of two modalities are substantial. However, when two poor quality datasets are fused, noticeable gains in recognition performance are realized when using the novel feature extraction approach. Finally, feature-fusion guidelines are proposed to provide the necessary insight to leverage the rich information effectively when fusing multiple biometric modalities at the feature level. These guidelines serve as the foundation to better understand and construct biometric systems that are effective in a variety of applications.
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- Date Issued: 2018
Investigating Grade 3 learners’ changing mathematical proficiency in a maths club programme focused on number sense progression
- Authors: Hebe, Gasenakeletso Ennie
- Date: 2018
- Subjects: Mathematical ability -- Testing , Education, Elementary -- South Africa , Mathematics -- Study and teaching (Elementary) -- Activity programs , Mathematics -- Remedial teaching , South African Numeracy Chair Project (SANCP)
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62200 , vital:28137
- Description: Recent international reports, for example TIMSS (2011 & 2015), point to serious challenges in South African learner performance in Mathematics and Science. Of greatest concern is that research findings (e.g. Graven, Venkat, Westaway and Tshesane 2013) suggest that many South African learners show signs of mathematical knowledge gaps in the lower grades. Hence, there is a need to address challenges of this nature very early in Foundation Phase. This study was undertaken with a view to contribute towards addressing mathematical challenges encountered by learners in Foundation Phase. This empirical enquiry was undertaken under the auspices of the South African Numeracy Chair Project (SANCP) at Rhodes University whose mission is to develop sustainable ways of improving quality teaching and learning of Mathematics in South Africa. A relatively new SANCP programme called Pushing for Progression (PfP) run as part of the after-school Maths Clubs to develop the number sense and four Operations in learners was used to achieve the research aims of this study. Research participants were drawn from the Maths Clubs established by the researcher in a small rural town of Ottosdal in the North West Province of South Africa. This Study is grounded on the Vygotskian perspective and uses the interpretivist qualitative research method for data collection and analysis. Sampling was done opportunistically by enlisting participants (12 teachers and 117 learners) on the basis of their availability and willingness to participate. Pre- and post-assessment of learners’ proficiency on the four Basic Operations was conducted at the beginning and at the end of the research project, respectively. This was done to determine the impact of the project on learner performance. Data analysis was done thematically and through the comparison of learner results of the pre- and post-assessment. The findings point to the effectiveness of the PfP Programme in learner performance. This can be deduced from improved scores between pre- and post-assessment and the observations made by participant-teachers on their respective club learners’ mathematical proficiencies. Accordingly, based on the findings, this study recommends, inter alia, that since the PfP programme is still in its early stages, similar research be conducted elsewhere. Additionally, the Department of Basic Education could consider exploring the PfP programme as one of several other strategies to help improve learner proficiency in Mathematics.
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- Date Issued: 2018
Investigating the influence of ring substitution on indole hydrogen bonding, with amino acids
- Authors: Nel, Donovan
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63509 , vital:28426
- Description: Expected release date-April 2019
- Full Text: false
- Date Issued: 2018
Investigating the viability and performance of a pilot scale Fly Ash/Lime Filter Tower (FLFT) for greywater treatment and the fate of Triclosan post treatment
- Authors: Nondlazi, Sinoyolo
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63704 , vital:28473
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
Investigating thermal physiology as a tool to improve the release efficacy of insect biological control agents
- Authors: Griffith, Tamzin Camilla
- Date: 2018
- Subjects: Aquatic weeds -- Biological control , Water hyacinth -- Biological control , Insects -- Physiology , Miridae -- Effect of low temperatures on , Cold adaptation , Insects as biological pest control agents , Eccritotarsus catarinensis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63301 , vital:28391
- Description: Biological control is commonly used for the control of invasive aquatic weeds, which often involves the release of multiple host-specific agents. Releasing multiple agents has inherent safety concerns as the introduction of each new agent is associated with risks, but is often required to improve control where establishment is limited. Climatic incompatibility between the agent’s thermal physiology and its introduced range often causes agents to fail to establish. However, it has been suggested that the thermal physiology of insects is plastic. Therefore, the potential to manipulate their thermal physiologies before releasing them into the field needs to be explored; reducing the need to release additional agents, thereby ensuring the safety of biological control. This thesis therefore aimed to firstly, determine whether season and locality influenced the thermal physiology of two field populations of a water hyacinth (Eichhornia crassipes) control agent, the mirid Eccritotarsus catarinensis; one collected from the hottest establishment site, and one collected from the coldest establishment site in South Africa. Their thermal physiology was significantly influenced by season and not by the sites’ climate, suggesting their thermal physiology is plastic under field conditions. Secondly, the classical method of determining the lower critical thermal limit (CTmin), and a new respirometry method of determining this limit, compared the thermal physiology of two Eccritotarsus species reared in quarantine. Eccritotarsus catarinensis was significantly more cold tolerant than the more recently released Eccritotarsus eichhorniae, despite similar maintenance conditions, and as such, was used to establish whether cold hardening under laboratory conditions was possible. Successfully cold hardened E. catarinensis had a significantly lower CTmin compared to the field cold acclimated population, suggesting that cold hardening of agents could be conducted before release to improve their cold tolerance and increase their chances of establishment, allowing for further adaptation to colder climates in the field to occur. Increasing establishment of the most effective agents will decrease the number of agents needed in a biological control programme, thus encouraging a more parsimonious approach to biological control.
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- Date Issued: 2018
Isolation, identification and genetic characterisation of a microsporidium isolated from the carob moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae)
- Authors: Lloyd, Melissa
- Date: 2018
- Subjects: Pyralidae , Pyralidae -- Genetics , Pyralidae -- Phylogeny , Pyralidae -- Pathogens , Cladistic analysis , Transmission electron microscopy , Carob moth (Ectomyelois ceratoniae)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61894 , vital:28075
- Description: Carob moth, Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) is an economically important pest, yet its biology and pest status on citrus in South Africa was, until recently, poorly understood. A study was initiated to determine the cause of collapse of a laboratory carob moth colony that was established to investigate the biology of carob moth on citrus and to develop integrated management strategies for the pest. An organism was isolated from deceased larvae and was morphologically identified as a microsporidium, based on transmission electron microscopy. Microsporidia are obligate intracellular parasites that have been found to infect almost all eukaryotes. Several Nosema species have been isolated from economically important insect pests, yet little genetic information is available from online databases for identification. Mature spores were recovered and measured using transmission electron microscopy. Spores were ovocylindrical with a wrinkled exospore, and had a length of 2.8 ± 0.02 pm and a width of 1.6 ± 0.04 pm. The identity of the microsporidium was confirmed by PCR amplification, sequencing and analysis of the regions encoding the ribosomal RNA. BLAST analysis of the different rRNA regions amplified showed that the microsporidium shared a 96 - 99 % identity with Nosema sp. M-Pr, Nosema carpocapsae, Nosema oulemae, Nosema sp. CO1, Microsporidium 57864, and Nosema bombi. Phylogenetic analysis of the SSU and LSU rRNA genes showed that the microsporidium clustered with the Nosema / Vairimorpha clade, supported by a bootstrap value of 100. The organisation of the RNA cistron was determined by PCR amplification using the primer set 18f and L1328r to be 5’-SSU-ITS-LSU-IGS-5S-3’, which confirms the placement of the microsporidium within the Nosema / Vairimorpha clade. Because the BLAST results showed a close relationship with Nosema carpocapsae, a microsporidium infecting codling moth, the pathogenicity of the microsporidium was tested against codling moth by inoculating artificial diet with a high spore concentration of 1.1 x 107 spores/ml and a low spore concentration of 1.1 x 104 spores/ml. DNA was extracted from deceased larvae inoculated with the high concentration, and PCR of the SSU rRNA gene and bacterial 16S region was performed. Mortality in the high concentration experiment was significant (p = 0.05), but the cause of infection was determined to be a bacterium, through sequencing and BLAST analysis of the bacterial 16S rDNA. The bacterium shared a 99 % identity with Bacillus cereus. Percentage mortality (p = 0.09), larval mass (p = 0.09) and instar (p = 0.24) did not differ significantly between treatments in the low concentration experiment. DNA was extracted from the larvae and PCR amplification of the SSU rRNA gene was performed to determine whether microsporidia were present. No SSU bands were observed in any of the treatments and percentage mortality was not significant, thus it was determined that no infection occurred. This is the first study to report the genetic characterisation of a microsporidium isolated from carob moth and provides important genetic information for classification of microsporidia within the Nosema / Vairimorpha clade. It is also one of few studies in which the complete rRNA cistron of a species within the Nosema / Vairimorpha clade has been sequenced. The identification of a microsporidium from a laboratory colony of carob moth is important as it provides information about pathogens infecting the carob moth and constraints to carob moth rearing, which is useful for further studies on rearing carob moth and for establishment of a clean colony for research purposes.
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- Date Issued: 2018
Judging psycholegal reporting in civil court proceedings in the Eastern Cape
- Authors: Marais, Claire Anne
- Date: 2018
- Subjects: Court proceedings -- South Africa -- Eastern Cape , Evidence, Expert -- South Africa -- Eastern Cape , Forensic psychology -- South Africa -- Eastern Cape , Quality Rating Scale (QRS) , Psycholegal reporting -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/62999 , vital:28352
- Description: Purpose: The primary purpose for this research was to evaluate the quality of psycholegal reports, and the qualification of the authors. Previous research had revealed generalised poor practices in psycholegal report writing and the authors seemed unqualified as expert witness. This negatively influenced the impression and usefulness of expert psychological opinion in South African courts. The secondary purpose was to compare the results to those determined by Ireland (2012), which was a useful benchmark study in the UK as her findings corresponded with the literature. Method: This archival research analysed a hand-search sample of 20 reports written by 20 psychologists based nationally. These reports were submitted as expert opinion in civil proceedings in the Grahamstown Division of the Eastern Cape High Court between 2011 and 2016. Ireland and Pinschof’s (2009) measure ‘Quality Rating Scale’ was adapted for a South African context and used to evaluate quantitatively the reports. Focus was on the reports’ contents (fact and opinion), methods, process and overall rating, and the qualification of the authors. Results: Overall, two-thirds of the reports were rated as ‘good’ and ‘very good’. The results were generally more positive than Ireland’s (2012) findings. However, there were practices in the report writing that were deemed detrimental to the quality of the expert’s opinion. This included vague referral questions and unclear basis for concluding opinions and diagnosis. There was also a lack of discussions surrounding the scientific trustworthiness of testing methods and absent ethical considerations. Lastly, the specialised expertise of the experts was not adequately documented. Conclusion: The findings painted a more positive picture of psycholegal reporting in South Africa than illustrated in previous research, which seemingly relied on anecdotes and subjective surveys. This study used a systematic and objective measure. The findings of this study, previous research and ethical Rules of Conduct were used to consider recommendations for psycholegal report writing, and the improvement of the field of psycholegal work. Lastly, the focus of future research was discussed.
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- Date Issued: 2018
Key considerations for novel aptamer generation and aptasensor platform design: a case study on human α-thrombin and histamine as sensor targets
- Authors: Ho, Lance St John
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63534 , vital:28432
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
Knowledge and knowers in Educational Leadership and Management (ELM) Master’s Programmes in South Africa
- Authors: Kajee, Farhana Amod
- Date: 2018
- Subjects: Educational leadership -- South Africa , Teachers -- Training of -- South Africa , Education, Higher -- South Africa , Master of education degree -- South Africa , Knowledge, Theory of , Educational sociology -- South Africa , Education, Higher -- Aims and objectives -- South Africa , Legitimation Code Theory (LCT)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60698 , vital:27819
- Description: This dissertation examines the knowledge and knower practices in the Master’s in Educational Leadership and Management (ELM) coursework programmes at South African public universities. This study was prompted by my growing awareness of problems and tensions in the field of ELM generally, and at the level of programme design of the M Ed degree in particular. Many of these had been identified by a national audit of coursework M Eds in ELM (CHE, 2010), and this study sought to find a way of theorising these with a view to improving both course design and teaching. To this end I employed Maton’s Legitimation Code Theory (LCT) which enables critical engagement with knowledge and knowers in programmes, how they are positioned, and how this positioning may be problematic. Hence my first research question sought to discover and critique what counted as knowledge in these programmes and why, while the second asked how knowers were positioned, and why this had come to be the case. LCT has its roots in the work of Bernstein and Maton, whose preoccupation with curriculum was/is driven by a sense of social justice: if we can understand how and why the curriculum is organised and presented in a particular way, it becomes possible to re-imagine teaching and learning, making it accessible to a broader, more inclusive body of learners. The study also drew on critical realism as an underlabourer. This philosophy provided a nuanced understanding of ontology, encouraging and enabling me, as researcher, to unearth causal mechanisms driving the status quo. Only seven South African universities currently offer the coursework option of a Master’s degree in ELM, compared to thirteen when the audit was conducted in 2010. Six of the universities agreed to take part in the study. Data was gathered through content analysis of the six course outlines and interviews with individual co-ordinators or academics centrally involved in the programmes. Through the development of a translation device I was able to establishing that a knower code was dominant in the programmes. Using this point as my departure, I interrogated the knowledge practices and found that different types of knowledge were being privileged across the programmes, with some having a practical/professional leaning and others a more academic/theoretical orientation. The resultant tension does, I argue, restrict knowledge building and helps to account for the fact that the field is generally considered to be under-theorised. The fact all of these programme are registered with the same national qualifications authority, ostensibly following the same national guidelines for Master’s degrees is worrying. The study attempts to find underlying, historically significant reasons for this unevenness. An analysis of the programmes revealed a leaning towards supportive pedagogical approaches. While all programmes promote a cultivated gaze their purposes are not always the same. While a hegemonic practices potential for opening counts as knowledge, cultivated gaze can enable transformation, it can also encourage that can impede real change and empowerment. The study has the up much needed debate on what is meant by a Master’s in ELM, what and what kinds of knower are envisaged.
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- Date Issued: 2018
Knowledge practices and student access and success in General Chemistry at a Large South African University
- Authors: Mtombeni, Thabile Nokuthula
- Date: 2018
- Subjects: Chemistry -- Study and teaching (Higher) -- South Africa , Knowledge management , Education, Higher -- Curricula -- South Africa , Critical realism , Social integration -- South Africa , Educational equalization -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62873 , vital:28305
- Description: This dissertation reports on an investigation into the structuring principles of the General Chemistry curriculum at a Large South African University (LSAU). Student learning in the introductory modules of General Chemistry is critical for access to a range of fields since it is a requisite course for a variety of degree programmes. However, there is ample evidence that success in this subject remains a major challenge, particularly for black students. My quest in this study was to explore how the curriculum could enable greater epistemic access and thus include more students in science programmes at the LSAU. I investigated the organising principles underlying the curriculum practices of the General Chemistry module and explored the effects of the curriculum structure on student learning. Theoretically and conceptually, the study was underpinned by a social realist approach which holds that knowledge is stratified, differentiated, and has real emergent properties, powers and effects. The research question that I attempted to answer in this study was: How do knowledge practices privileged in the General Chemistry curriculum at the LSAU enable or constrain student learning? I adopted an intensive research design approach to conduct a qualitative case study using social realism and LCT as theoretical and analytical lenses. I used empirical data such as curriculum documents and interviews with lecturers to uncover the underlying generative mechanisms of the curriculum. I adopted a multi-layered data analysis process to make visible the underlying organising principles informing knowledge practices in the curriculum so that I could explain their potential effects on student learning. The first level of analysis explored the context of the curriculum and associated knowledge practices, and examined the pedagogic discourse evident in the curriculum. The second level of analysis revealed the inner logic structuring the curriculum and the associated knowledge practices. I used Maton’s Legitimation Code Theory (LCT): Specialisation to identify the specialisation codes, gazes and insights generated by the curriculum. For the third level of analysis, LCT: Semantics was used to generate the semantic profiles of learning activities to determine the extent to which the curriculum structure made cumulative learning possible. From the findings, it is evident that the verticality of knowledge in General Chemistry points to a recontextualising principle that prescribes the selection and arrangement of knowledge, and the special relationship of actors and discourses. As a result, the strong framing of the instructional discourse of General Chemistry curriculum structure is likely to constrain epistemological access for large numbers of students. In order to improve epistemological access to the field, weaker framing of the instructional discourse in introductory science is necessary. Weaker framing of the General Chemistry curriculum would require, in particular, changes to pacing, and that the evaluative criteria are made explicit. This is especially necessary when certain abstract and complex curricular content is taught, especially in the first semester. The findings also indicate that the nature of the organising principles in the curriculum are significant for improving epistemological access to knowledge. In terms of LCT: Specialisation, the General Chemistry curriculum generated a knowledge code and downplayed differences among social categories of students, thus positioning all equally in relation to the knowledge and practices of the field. Therefore, the structuring of the curriculum emphasises and legitimates students who have attained specialist knowledge without considering the nature of the new student coming into the educational setting. Simply, what is privileged is both the object of study (theoretical knowledge) and how it is studied (procedural knowledge). This finding is in line with the general outcomes of Chemistry education. In addition, the purist insight generated by the curriculum further attests to where the emphasis is placed in the curriculum. I argue that the lack of social relations in the curriculum poses a challenge for the holistic development of students as science knowers. The analysis of the learning activities shows rapid code shifts that indicate changes in cognitive demand and modes of thinking required of students. I argue that signposting the changes in complexity of knowledge and in the mode of thinking required could make learning, and thus epistemological access, more possible. Given the imperative of access to powerful knowledge, I contend that the curriculum should be reshaped to enable epistemological access for more students.
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- Date Issued: 2018
Leadership development within a Learner Representative Council (LRC) in a rural secondary school in the Oshana region, Namibia
- Authors: Da Silva, Rolens
- Date: 2018
- Subjects: Student participation in administration Namibia , Student government Namibia , Educational leadership Namibia , Qualitative research
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62808 , vital:28282
- Description: The Namibian Education Act (Namibia. Education Act No. 16 of 2001) mandates state secondary school learners to be included in school leadership through a body of learners known as the Learner Representative Council (LRC). The few studies carried out on the LRC in schools reveal that very little has been achieved in terms of learner leadership development. This study explored and provided insight into possible reasons for this, and recommendations. The research questions driving the study were: How is learner leadership currently understood and practised in the school? What are the enabling and constraining factors in the school as far as learner leadership development is concerned? And what can be done to promote learner leadership development? This study is an interpretive case study of learner leadership in the LRC in a Namibian state secondary school in the Oshana region. The conceptual framework used was distributed leadership. The Cultural Historical Activity Theory (CHAT) was used as an analytical tool. The research participants were the LRC members, school principal, Heads of Departments representing the school management members, the School Board Chairperson representing parents and the LRC liaison teacher and were all purposively selected. Data was collected through document analysis, open-ended questionnaires, interviews and non-participant observation. Data analysis took the form of inductively – identifying themes emerged from the data and deductively – using CHAT to surface the systemic contradictions within the learners’ activity system. The data revealed that learner leadership was mostly understood from a management perspective and equated with the formal authority of the LRC in the school. The data further revealed that the LRC performed more leadership roles stretched from inside the classroom, outside the classroom, on the School Board and outside the school. To capture this complexity, I developed a model which may prove useful for future studies of learner leadership. The data also indicated that much support was offered to the LRC members in the school; for example, support from the LRC liaison teacher, the School Management Team and generally from the school, through LRC leadership training. Using CHAT, the findings revealed that the historical context and cultural conventions contradicted the LRC leadership development in the school. In line with a distributed leadership theory, the study recommends that learner leadership should not be limited by position and authority but should be exercised by all learners, through the development and establishment of learner leader clubs in the school. The study also recommends that schools should embark on change initiatives which challenge their traditionally held beliefs and attitudes.
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- Date Issued: 2018
Leadership development within a learner representative council: a Namibian primary school case study
- Authors: Tjihuro, Jaqueline
- Date: 2018
- Subjects: School management and organization Namibia , Educational leadership Namibia , Student participation in administration Namibia , Student government Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/61558 , vital:28036
- Description: Learners in Namibian primary schools are seemingly not brave enough to stand and raise their voice on issues that concern them. This is what Shekupakela-Nelulu (2008) wrote after a study she conducted on the Learners’ Representative Council (LRC) of a school in Namibia. She refers to a time when “the involvement of students in school affairs was seen by the regime as a political act and attempts by student leaders to involve themselves in educational issues were often quashed” (ibid., p. i). This situation will be all too familiar to South African readers, where a public holiday, Youth Day, was declared to mark the apartheid regime’s brutal treatment of learner protestors on June 16, 1976. While Namibia has not experienced events of such magnitude, the notion of learner voice is equally problematic and worthy of investigation. The absence of leadership development opportunities for learners has led to this research study which seeks to answer the central research question: How can learner leadership be developed in a LRC? I used an interpretive paradigm, adopting a qualitative approach in the study. Concurrently, the study was framed and guided by the second generation of Cultural Historical Activity Theory (CHAT) as an analytical tool to achieve my research goal. The following questions guided the study in two phases. Phase one: What were the perceived causes for the nonsustainability of the learner leadership (LL) club at the school? Phase two: How is the notion of learner leadership understood in the school? How is leadership developed on the LRC? What enables and constrains leadership development of learners on the LRC? The research participants were thirty LRC members from grades 6 and 7 and15 teachers who teach the LRC members. The principal and three HOD’s were also research participants being part of the Senior Management team. One of the HOD’s also fulfils the role of the guardian teacher to the LRC. A school board chairperson also participated in the Change Laboratory Workshop. Data was generated through multiple data sources such as questionnaires, individual interviews, a focus group interview and observation. The findings from phase one of the study revealed that the learner leadership club’s intervention was a success during the 2014 academic year, but the absence of the learner leadership club as an extra-mural activity affected the sustainability of the club into the next academic year 2015. Findings from phase two revealed that leadership opportunities did exist at the school for learner leadership development. However, a few challenges emerged relating to traditional views of leadership and constraining factors that could affect learner leadership development at the school. Thus, Change Laboratory workshops were held to find solutions to the challenges, in order to promote and enhance learner leadership development, hopefully for the future of the Namibian child.
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- Date Issued: 2018
Learner voice and leadership: a study of a Learner Representative Council in a primary school in Namibia
- Authors: Kapuire, Dominika Bertha
- Date: 2018
- Subjects: Educational leadership -- Namibia , School management and organization -- Namibia , Student government -- Namibia , Student participation in administration -- Namibia , Education, Primary -- Namibia , Cultural Historical Activity Theory
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62177 , vital:28135
- Description: Numerous literature world-wide emphasises the significance of learner voice and leadership in schools. These concerns are not new to the education system of Namibia, because the education system is shaped by policy which encourages the voices of all stakeholders in the schools. The Education Act 16 of 2001 introduced the Learner Representative Council (LRC) as a legitimised body in secondary schools which represents learners in school level decision-making. Learner Representative Council members in secondary schools are allowed to sit in on School Board meetings and voice their concerns about issues at the school. The Act also involved parents, allowing them to air their views on behalf of their children, by becoming part of the School Board. Although this is what the Act 16 of 2001 introduced, recent researchers have urged for the need to develop learner voice and leadership in schools, as many schools have turned a blind eye to its significance. This is also what prompted me to conduct a study on the development of learner voice and leadership. This research was conducted within the context of learner leadership at a primary school in the Otjozondjupa region, Namibia, focusing on the school’s existing Learner Representative Council (LRC). The study explores the underlying reasons for the current problems in the LRC structure and beyond, opening up leadership opportunities, and promoting learner voice at the school. Participants in the research were drawn from learners, teachers, heads of department, and the principal. As a qualitative case study in the interpretive paradigm, the study employed a range of data collection strategies - questionnaires, interviews, focus group interviews, observation and Change Laboratory (CL) workshops - to gather data to answer key research questions: How is the LRC currently involved in the leadership of the school? What are the factors inhibiting the development of learner leadership in the school? What opportunities exist for the development of learner voice and leadership within the LRC? How can learner voice and leadership be developed through Change Laboratory (CL) workshops? The research was underpinned by the second generation of Cultural-Historical Activity Theory (CHAT) as an analytical framework. CHAT had the potential to bring problems and challenges into focus, which was then used to open up expansive learning in the CL workshops. Data collected from the participants was surfaced as mirror data in these workshops. The study showed that the LRC was not active in their leadership roles and that they were not given enough opportunities to function freely in their roles. These learners were under a traditional system of leadership, whereby teachers had all the control and say in the learners’ leadership roles. The development of learner leadership was only recognised through the leadership training camp. Many factors that inhibited the development of learner voice and leadership also emerged in the study. Lastly, the notion of developing learner voice was also not understood by some teachers, which showed in their contradicting views. This study recommends that learner leadership should be developed, starting at an early age in the primary school. It also recommends that learners, however young, should be given a platform to contribute to the decision making at their schools.
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- Date Issued: 2018
Left-invariant optimal control problems of the Engel group: classification, stability, and integration
- Authors: McLean, Catherine Eve
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62949 , vital:28323 , http://doi.org/10.21504/10962/62949
- Description: Expected release date-April 2020
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- Date Issued: 2018
Long-term analysis of ionospheric response during geomagnetic storms in mid, low and equatorial latitudes
- Authors: Matamba, Tshimangadzo Merline
- Date: 2018
- Subjects: Ionospheric storms , Coronal mass ejections , Corotating interaction regions , Solar flares , Global Positioning System , Ionospheric critical frequencies , Equatorial Ionization Anomaly (EIA)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63991 , vital:28517
- Description: Understanding changes in the ionosphere is important for High Frequency (HF) communications and navigation systems. Ionospheric storms are the disturbances in the Earth’s upper atmosphere due to solar activities such as Coronal Mass Ejections (CMEs), Corotating interaction Regions (CIRs) and solar flares. This thesis reports for the first time on an investigation of ionospheric response to great geomagnetic storms (Disturbance storm time, Dst ≤ −350 nT) that occurred during solar cycle 23. The storm periods analysed were 29 March - 02 April 2001, 27 - 31 October 2003, 18 - 23 November 2003 and 06 - 11 November 2004. Global Navigation Satellite System (GNSS), Total Electron Content (TEC) and ionosonde critical frequency of F2 layer (foF2) data over northern hemisphere (European sector) and southern hemisphere (African sector) mid-latitudes were used to study the ionospheric responses within 15E° - 40°E longitude and ±31°- ±46° geomagnetic latitude. Mid-latitude regions within the same longitude sector in both hemispheres were selected in order to assess the contribution of the low latitude changes especially the expansion of Equatorial Ionization Anomaly (EIA) also known as the dayside ionospheric super-fountain effect during these storms. In all storm periods, both negative and positive ionospheric responses were observed in both hemispheres. Negative ionospheric responses were mainly due to changes in neutral composition, while the expansion of the EIA led to pronounced positive ionospheric storm effect at mid-latitudes for some storm periods. In other cases (e.g 29 October 2003), Prompt Penetration Electric Fields (PPEF), EIA expansion and large scale Traveling Ionospheric Disturbances (TIDs) were found to be present during the positive storm effect at mid-latitudes in both hemispheres. An increase in TEC on the 28 October 2003 was because of the large solar flare with previously determined intensity of X45± 5. A further report on statistical analysis of ionospheric storm effects due to Corotating Interaction Region (CIR)- and Coronal Mass Ejection (CME)-driven storms was performed. The storm periods analyzed occurred during the period 2001 - 2015 which covers part of solar cycles 23 and 24. Dst≤ -30 nT and Kp≥ 3 indices were used to identify the storm periods considered. Ionospheric TEC derived from IGS stations that lie within 30°E - 40°E geographic longitude in mid, low and equatorial latitude over the African sector were used. The statistical analysis of ionospheric storm effects were compared over mid, low and equatorial latitudes in the African sector for the first time. Positive ionospheric storm effects were more prevalent during CME-driven and CIR-driven over all stations considered in this study. Negative ionospheric storm effects occurred only during CME-driven storms over mid-latitude stations and were more prevalent in summer. The other interesting finding is that for the stations considered over mid-, low, and equatorial latitudes, negative-positive ionospheric responses were only observed over low and equatorial latitudes. A significant number of cases where the electron density changes remained within the background variability during storm conditions were observed over the low latitude stations compared to other latitude regions.
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- Date Issued: 2018
Macroinvertebrate and diatom assemblage responses to pollution, with emphasis on salinity, in the Kat River, Eastern Cape South Africa
- Authors: Mgaba, Ntombekhaya
- Date: 2018
- Subjects: Water -- Pollution -- South Africa -- Kat River , Stream salinity -- South Africa -- Kat River , Sewage disposal plants -- South Africa , Environmental monitoring -- South Africa -- Kat River , Water quality -- South Africa -- Kat River , South African Scoring System version 5 (SASS5) , Macroinvertebrate Response Assessment Index (MIRAI)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63279 , vital:28389
- Description: Salinity has been implicated as one of the major contributors to deteriorating water quality of freshwater ecosystems around the globe. In South Africa, anthropogenic activities such as mining, agriculture, industry and wastewater treatment works (WWTWs) are the major sources of increasing salinity levels of freshwater resources. The main focus of this study was to assess the impact of salinity on water quality of the Kat River using macroinvertebrates and diatoms as bioindicators. Biomonitoring using macroinvertebrates and diatom communities and concurrent sampling of water physicochemical variables were conducted bi-monthly from December 2015 to November 2016.This period covered summer and winter, and the study was conducted at five selected sites (Sites 1, 2, 3, 4 and 5) along the length of the Kat River. For macroinvertebrates biomonitoring, the South African Scoring System version 5 (SASS5) and Macroinvertebrate Response Assessment Index (MIRAI) were applied to collect and analyse data, while the Taylor et al (2006) protocol for collecting and analysing diatom assemblages was modified and used for diatom collection and analysis. Water physicochemical variables, including hydrogen ion concentration (pH), electrical conductivity (EC), dissolved oxygen (DO), temperature, turbidity and stream flow were determined in situ using appropriate multiprobe meter and/or techniques. Nutrients (NO3-N, NO2-N, NH4-N and PO4-P) were analysed in the laboratory using appropriate analytical methods. All data were subjected to appropriate statistical analyses and statistical decisions were made at an alpha value of 0.05. Particularly, multivariate analyses of both macroinvertebrates and diatoms assemblages were conducted using canonical correspondence analysis and Bray-Curtis similarity analysis, while indicator species analysis was used to determine which species is/are more significant with respect to biomonitoring in the Kat River. Biotic diversity indices were also measured and used to discriminate between least and most impacted sites. The Kat River water quality was found to have experienced a varying degree of modification compared to Generic Resources Water Quality Objectives limits. Change in DO, stream flow, EC, nutrients and turbidity exerted the greatest influenced on the macroinvertebrates assemblage structure, with organisms at Sites 4 and 5 (downstream sites) showing more significant negative impact compared to organisms at Sites 1, 2 and 3 (upstream sites). Analysis of the diatom biomonitoring showed more negative impact at Sites 2, 4 and 5 compared to Sites 1 and 3. Fort Beaufort Wastewater Treatment Works and small-scale farming activities, as well as leaking of pipes carrying sewage, were found to be the likely major sources of anthropogenic activities responsible for the observed increased salinity and other pollutants in the Kat River. Overall, this study found macroinvertebrates (identified up to the family level) as good for biomonitoring to assess or predict water quality of the Kat River, while diatoms were found to be most suitable for biomonitoring to assess salinity in the Kat River.
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- Date Issued: 2018
Malume’s bones
- Authors: Mokhele, Sizakele
- Date: 2018
- Subjects: Creative writing (Higher education) -- South Africa , South African poetry (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63132 , vital:28366
- Description: My poetry is about real stories: poverty, love, politics, past pains and healing. I try to follow the example of Amiri Baraka who says his poetry is whatever he thinks he is, that he makes poetry with “what can be saved out the garbage of our lives”. My collection also preserves and embraces demotic language, which is also a part of who I am. I am influenced by Baraka’s and Ike Muila’s use of demotics, and the way that poets such as Antonio Jacinto, Costa Andrade and Mafika Gwala tackle political matters in a colourful and powerful way. I have also been inspired by ancient Chinese poets to explore love and eroticism, particularly how it plays out in the eyes of my people.
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- Date Issued: 2018
Mannich base metal complexes and their thiocyanate analogues as catalysts in the oxidation of Catechol
- Authors: Ayeni, Ayowole Olaolu
- Date: 2018
- Subjects: Mannich bases , Catechol , Catechol -- Oxidation , Thiocyanates , Catalysts
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62339 , vital:28156
- Description: The study focused on the design of new Cu(II) and Fe(III) complexes, with or without thiocyanate (NCS-), as possible candidates of catechol oxidation using 3,5-di-tert-butyl catechol (3,5-DTBC) as substrate. Two classes of Mannich bases were studied depending on the active methylene group from which they were formed, being either p-cresol or acetaminophen. The ligands were characterised by 1H and 13C NMR spectroscopy. Crystal structures of three of the ligands are newly reported, along with detailed discussion of polymorphism observed in one of the ligands, and the nature of the hydrogen within the ligands in the solid state as well as in solution. The Mannich bases behaved as bidentate (NO), tridentate (NNO) and tetradentate (NNOO) ligands on coordination to Cu(II) and Fe(III) ions in which the hydroxyl group may be protonated or deprotonated. Coordination was determined by IR spectroscopy, investigating shifts in vOH, vC-O and in vCNC of the Mannich bases. The vCNC stretching frequencies v1 and v2 of asymmetrical piperazine Mannich bases were observed to shift upward in few cases upon complexation and this is attributed to (chair-boat) conformational change. The mode of coordination of the thiocyanate was determined by IR spectroscopy. Of the forty metal complexes investigated, six groups of metal complexes were identified as follows: (i) Ma(Ln)aClb-cH2O; (ii) Ma(HLn)a(NCS)aClb; (iii) Ma(Ln)a(NCS)aClb; (iv) Ma(HLn)aClb-cH2O; (v) Ma(Ln)a(NCS)a-cH2O; (vi) Ma(HLn)a(NCS)a-cH2O where a = 1 - 2 ; b = 1 - 4, c = 1 - 8. Molar conductivity values of 4.38 - 161.77 Q-1.cm2.mol-1 for the Cu(II) and Fe(III) complexes in DMSO showed that they range from non-electrolytes to 1:1 and 1:2 electrolytes. Electronic spectra for the ligands and the complexes were conducted in DMF and DMSO. The ligands are characterised by and n→n* and n→n* transitions. Intraligand charge transfer transitions peculiar to the nitro group were observed at about 430 nm for the nitro containing ligands. On coordination, these bands overshadowed the d-d transitions particularly for the nitro-Mannich bases. On complexation, ligand to metal charge transfer transitions associated with the hydroxyl were observed between 320 - 420 nm. Charge transfer transitions associated with the thiocyanates were also observed and discussed. The d-d transitions for high spin Fe(III) complexes are spin forbidden and generally uninformative. Those of Cu(II) are spin allowed and allow tentative structural proposals. Square planar and octahedral geometry are generally prevalent in the Cu(II) complexes with trigonal bipyramidal observed in few instances. The Fe(III) complexes are generally octahedral. Thirty-nine of the forty synthesised Cu(II) and Fe(III) complexes were catalytically active on the substrate (3,5-DTBC) in DMF with turnover rates (kcat) reported in the range of 1.86 ± 0.09 to 112.32 ± 3.72 h-1. From this pool of complexes, sixteen isostructural pairs were identified in terms of geometry, molecular formula and the source of the Mannich base and the following conclusions were made: The presence of thiocyanate in the metal complexes reduce catecholase activity; the Cu(II) complexes generally have better activity but the Fe(III) complexes become more relatively active with highly electron donating groups while the Cu(II) complexes become less; dinuclear complexes have greater activity than the mononuclear.
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- Date Issued: 2018