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An assessment of restoration efficacy : hydrological, geomorphological and vegetative responses to restoration measures at the Colbyn Valley Nature Reserve
Get PDFAbstract: Wetlands provide valuable ecosystem services such as underground and surface water supply, hydrological stability, flood, and drought control. These ecosystems ensure the survival of different aquatic biota. Regardless of their role in the environment, wetland ecosystems have been degraded or are at risk of being destructed because of many unregulated activities happening in and around them. The degradation or loss of wetlands results in a real cost to the environment and society due to their inability to provide these ecosystem services. Due to their unique nature, most wetlands, even though degraded, have an ability to perform some of their functions. Restoring and protecting wetland ecosystem services will secure the key benefits provided by wetlands and deliver a return on investment for the benefit of the environment and society. The Colbyn Valley Wetland in the Hartbeesspruit and located within the Colbyn Valley Nature Reserve has been rehabilitated by the City of Tshwane and the Working for Wetlands Programme of the Department of Forestry, Fisheries and the Environment. However, the ecological monitoring of restoration efficacy has been neglected. This study therefore, assessed the efficacy of restoration measures implemented by the City of Tshwane and Working for Wetlands Programme in terms of ecosystem services through the assessment of hydrological, geomorphological and vegetation responses...M.Sc. (Aquatic Health
A numerical study of fourth-order nonlinear degenerate diffusion equation using compact finite differences
Get PDFAbstract: This study presents a high-order numerical method based on a uniform mesh in order to obtain a highly accurate solution to the fourth-order nonlinear degenerate diffusion equation that arises in the context of the surface tension-driven flow of thin liquid films. This study aims to demonstrate that thin liquid film flow under the influence of surface tension is a common occurrence, as well as to examine the underlying physics of contact line motion. Secondly, to emphasize the numerous advantages of compact finite difference schemes, in which the derivative is approximated by solving a tri-diagonal or penta-diagonal set of equations at each time step. This research delves into two fields: fluid mechanics and numerical methods. A thin liquid film flowing down an inclined solid substrate under the influence of surface tension is considered. The challenges posed by the region close to the advancing contact line and the effect of surface tension are covered in a brief overview of thin liquid film flow. We give a brief overview of numerical methods. The porous media equation and the fourth-order nonlinear degenerate diffusion equation are introduced, linearized, and numerically treated using a sixth-order compact finite difference scheme. The quasilinearization method is used to linearize both equations. We semi-discretize using the Crank-Nicolson method in the temporal direction, while in the spatial direction, we discretize using the sixth-order compact finite difference scheme. A stability analysis is carried out to prove that the proposed method is unconditionally stable. The credibility of the proposed method is proved using the verification method, which is a process whereby the solution of the proposed method is compared to a well-established solution. Several numerical examples are carried out for the porous media equation, and a good agreement between our solutions and the exact solutions is observed. Numerical results, visualized in terms of tables and graphs, are presented to validate the proposed method. A comparative study is performed between the proposed method and other very good numerical methods in order to show that the proposed method provides accurate and efficient numerical solutions for thin film flow problems. A considerable computational advantage for the proposed method over other numerical methods is observed.M.Sc. (Applied Mathematics
Measuring the effectiveness of outlier detection techniques in cluster analysis
Get PDFAbstract: Outlier detection, the discovery of objects that deviate from normal behaviour, is crucial in many application domains. To detect them, a variety of algorithms have been proposed. These algorithms detect outliers using specific definitions of the concept of outliers, that is, their performance depends mainly on their context of application. In addition, their performance also depends on the evaluation measure used. Therefore it is crucial that relevant evaluation measures be used when evaluating the detection algorithms, since an algorithm can obtain a high detection score by correctly classifying the non-outliers alone. In this research, five outlier detection algorithms, namely k-Nearest Neighbour (k-NN), Local Outlier Factor (LOF), Connectivity-based Outlier Factor (COF), Influenced Outlierness (INFLO), and Angle-Based Outlier Detection (ABOD) are investigated to determine their accuracy in detecting outliers within data mining. These algorithms are applied to synthetic data with 10,000 simulations and a real-world (credit card transactions) dataset, where their performance is evaluated using the Receiver-Operating Characteristic (ROC) and Precision-Recall (PR) curves, along with their Area Under the Curves (AUC). Keywords: outlier detection, evaluation measures, cluster analysis, outliers, objects.M.Sc. (Mathematical Statistics
Domination versus independent domination and total domination in regular graphs and claw-free graphs
Get PDFAbstract: Please refer to full text to view abstract.D.Phil. (Mathematics
Professional development programmes that enhance mathematics instruction in primary schools
Get PDFAbstract: The study endeavoured to investigate the Professional Development Programmes (PDP) that enhance mathematics instruction in primary schools in Ekurhuleni District in Gauteng, South Africa. This study is framed within a situated learning theory using a qualitative research design phase, where focus group interviews were conducted and a standardized questionnaire was used. Data was analysed thematically. The following themes emerged on PD programmes in South Africa; the current types, their effectiveness, challenges highlighted by teachers, strategies to enhance them, the Department of Basic Education‟s policy on PD programmes and the school and individual level of PD programmes. As the Corona virus hit the world, it became clear that leaders had to move with speed and see that the academic year, especially in South Africa in all learning institutions would continue. As institutions shut down, learning had to somehow take place and resources were put in place to resource students with online learning and teaching, workshops for students done online, data supplied and even gadgets such as laptops offered to students so they could continue learning even under the circumstances. It was not possible though to achieve the “let no-one be left behind” slogan, due to many reasons, including corruption amongst government officials who slowed down the pace of resource distribution. The greatest observation was the need to narrow or eliminate the gap which was inherited many years ago perpetuated by the apartheid regime. In a nutshell, the themes and sub-themes made it possible to identify the good and barriers brought about by PDPs. Also, in the light of the findings, recommendations were presented that seek to answer the many questions that the study sought to find answers to. Future projections and suggestions and trajectories that the study might take were also mentioned. It was noted with sadness how our traditional instruction methods can be a handicap to the education sector and so it was recommended that the fraternity makes haste in adopting and embracing new effective PDPs that will equip teachers with skills to enhance mathematics instruction, even under the prevailing circumstances of the 5 Corona virus. As a researcher in this research report, it is my sincere hope that this study will raise interest and awareness amongst the policy makers of the sector to realize how essential it is to regard PDPs as the backbone to assisting teachers to assist learners to perform to their expectation and later compete with the global world and proudly raise the flag of South Africa.M.Ed. (Mathematics
The use of a poetry-based intervention to improve phonemic awareness in Grade 1 learners
Get PDFAbstract: The purpose of this study was to examine the effect of using a poetry-based intervention which aimed to improve the phonemic awareness of Grade 1 learners. A quasi-experimental pre- and post-test design was utilised in this study to “examine whether there is a causal relationship between independent and dependent variables” (Rogers & Révész, 2020, p. 2). In this study the independent variable was the poetry-based intervention and the dependent variable was the learners’ phonemic awareness. The intervention was framed around the phonemic awareness guidelines listed in the Grade 1 Home Language Curriculum Assessment Policy Statement (CAPS) (DoE, 2011, p. 14-.15). A Quasi-experimental design “lacks random assignment” (White & Sabarwal, 2014 p. 1). This design is utilized when randomization is not feasible or practical. Ten Grade 1 learners were non-randomly assigned to a comparison group or experimental group during the two-week-long poetry-based teaching intervention. The comparison group did not participate in the intervention; the group participated in the pre- and post-testing and their results were compared with those of the experimental group, which participated in the intervention. This was done to examine the impact of the poetry-based intervention on improving the phonemic awareness of Grade 1 learners. Data was collected using a pre- and post-test, learning artifacts and observations. The data collected was both qualitative and quantitative. The quantitative pre and post-test data was analysed using the difference and difference method for comparative analysis. The qualitative data attained from the pre- and post-test responses, learning artifacts and observations were analysed using the constant comparative method by (Maykut & Morehouse, 1994). The pre-test results revealed that there were no statistically significant differences between the two groups before the implementation of the intervention. This means that both groups were equivalent at baseline, they attained the same scores in the pre-testing. Following the implementation of the intervention and post-testing, a comparison of the results for both groups revealed that the experimental group performed better than the comparison group; there was an increase in their test scores and a decrease in scores for the comparison group. The qualitative analysis of learners’ test responses and learning artifacts as well as observation data corroborated these results. The results indicated that the poetry-based 5 intervention was effective in improving Grade 1 learners’ phonemic awareness. This shows that the use of poetry, and specifically limerick poems, are an effective and efficient learning and teaching tool that can be used to improve phonemic awareness in Grade 1 learners. Key words: phonemic awareness, limerick poems, rhyme, alliteration, poetry, quasi-experiment.M.Ed. (Childhood Education
Challenges faced by newly graduated teachers in using mother tongue to teach mathematics in the Oshana Region of Northern Namibia
Get PDFAbstract: Junior primary teachers need a solid knowledge base on how to handle the language effectively through applicable training. However, students at the University of Namibia in the Department of Early Childhood and Lower Primary Education are taught in English although the government language policy requires them to teach in mother tongue upon completion and appointment to schools. Teacher’s competency in the language of instruction is vital in mathematics’ achievement at junior primary level and it is important that if teachers are to teach in mother tongue, such practice should be extended to universities. The study aim was exploring challenges that newly qualified primary teachers experience when teaching mathematics concepts in mother tongue. The study will serve as an informed source of knowledge to be distributed to policy makers and teacher training institutions. Two interactive frameworks were adopted for this study: social constructivism theory and teacher agency. A qualitative, case study research design was employed. Data were collected through observations and semi-structured interviews. Findings indicate that teachers hold both positive and negative views on how the language policy affects their teaching of mathematics in mother tongue. Participants experienced challenges when teaching mathematics in mother tongue stemming from lack of appropriate training, profession-related problem and language issues. Coping strategies employed were; code-switching, seeking assistance, the use of drawings and manipulatives, and in some cases avoiding difficult terminology. The conclusion drawn is that teacher training plays a vital role in enabling teachers to develop agency. Moreover, socialisation at schools especially between novice teachers and veterans is important in ensuring novices receive guidance and employ effective coping strategies. It is recommended that the Ministry of Education facilitate the production of a mother tongue mathematics resources mathematics register in Oshindonga to be used in all schools and so establish uniformity of concepts and language used. KEY WORDS: Mother tongue, Oshindonga, Teacher training, Mathematics, Novice teachers, Junior Primary, Teacher agency, Social Constructivism.Ph.D. (Childhood Education
Lesson design in pre-service teacher education : the Science of learning and competencies for a fast-changing world
Get PDFAbstract: Teaching is complex and requires teachers to make informed decisions about the lessons they design and teach. Research suggests that the quality of novice teachers is linked to their initial preparation (Green et al., 2018). This study focused on one aspect of initial teacher education - namely, lesson design. This study therefore focused on equipping pre-service teachers to deal with the complexity in the classroom by preparing them to design powerful and purposeful lessons. In 2020, a colleague and I piloted a course in which we taught final year student teachers a new way of designing lessons, drawing on the body of scholarship dubbed the science of learning and the literature on competencies required for a fast-changing world. The science of learning, an amalgamation of research in education, neuroscience, psychology and cognitive science, provides evidence that helps us understand how people learn and how to support learning. A core premise of the course and this study was that such a course would serve the student teachers well in dealing with the complexities of teaching. The aim of the study was to explore what the student teachers had learnt from the implementation of the course. The research thus pursued the question: What do student teachers learn from the implementation of a teacher education course, which focuses on a lesson design approach that foregrounds principles derived from the literature on the science of learning and competencies for a fast-changing world? The course was designed, and its implementation planned before the COVID-19 pandemic. When the COVID-19 lockdown occurred in South Africa (in March 2020), all teaching had to be moved abruptly online. This situation prevailed for the entire year of implementing the course (excluding two months before the national lockdown). In light of this, the study sought to address an ancillary research question: What lessons can be learnt from the emergency remote teaching experience due to COVID-19 that can enrich the teaching of the course going forward?Ph.D. (Education
Synthesis of organic-inorganic hybrids for the electrocatalytic detection of biologically active molecules
Get PDFAbstract: Biomedical diagnosis and testing are often accompanied by inefficiencies, including high-priced tests, high detection limits, and interference from other biologically relevant molecules. To overcome such inefficiencies, the construction of electrochemical sensors has attracted interest due to their promising nature. They are simple to fabricate, and they offer high sensitivity and selectivity and low detection limits. In this research work, aniline and some transition metals were used to form complex materials as tools in electrochemical biosensor fabrication. In general, cyclic voltammetric (CV), square wave voltammetric (SWV), and chronoamperometric techniques were employed to model the aniline metal complexes electrochemical reactivities on working glassy carbon electrodes. Fourier transformed infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Nuclear magnetic resonance (NMR), and Elemental analyzer (EA) were used for further characterization. Furthermore, the materials were employed for electrocatalytic detection of biologically active molecules. In this regard, aniline-based metal complexes of bismuth, nickel, and cobalt were synthesized, characterized, and applied for the electrocatalytic detection of biologically active molecules. The complexes were synthesized by a simple complexation method using aniline as a ligand. The as-prepared complexes were deposited on the glassy carbon electrode (GCE) using the drop and dry method and investigated as an electrocatalyst for the efficient and sensitive detection of dopamine, iodine, uric acid, and cysteine. The hybrid materials showed good voltammetric sensor application for the detection of biologically active molecules. The results indicated that the electrodes modified with the complex materials could detect micromolar concentrations of dopamine, iodine, uric acid, and cysteine. The bismuth aniline complex (BAC) indicated 12.3 μM and 23.17 μM low detection limits for dopamine and iodine, respectively. The nickel aniline complex (NAC) revealed a 2.09 μM limit of detection and a wide linear range of 2.5 μM-220 μM for cysteine detection. The cobalt-aniline complex (COAC) indicated 9.26 μM and 9.52 μM limit of detection for uric acid and dopamine respectively, with linear ranges of 20 – 280 μM and 10 – 200 μM. The developed sensors could eliminate the interference of other biomolecules such as ascorbic acid, glucose, and histamine, to mention a few. The sensors were only selective to the analytes of interest. The electrochemical sensors developed in this work demonstrate good potential for the molecular diagnosis of neurological disorders such as Parkinson’s disease.D.Phil. (Chemistry
Sonic supersurfaces : spatial and legal thresholds to noise and silence
Get PDFAbstract: Please refer to full text to view abstract.M.Tech. (Architecture
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