4. Electronic Theses and Dissertations (ETDs) - Faculties submissions

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    Detecting Disease in Citrus Trees using Multispectral UAV Data and Deep Learning Algorithm
    (University of the Witwatersrand, Johannesburg, 2024-06) Woolfson, Logan Stefan; Adam, Elhadi
    There is a high prevalence, in South Africa, of fruit tree related diseases infesting lemon trees, subsequently affecting overall crop yield and quality. Ultimately, the income for the farmers is significantly diminished and limits the supply of nutritional food crops for the South African population, who already suffer from a high incidence of malnutrition. Currently, there are various methods utilized to detect diseases in fruit trees, however they pose limitations in terms of efficiency and accuracy. By employing the use of drones and machine learning methods, fruit tree diseases could be detected at an earlier stage of development and with a much higher level of accuracy. Consequently, the chances of remedying the trees before the disease spreads is greatly improved, and the supply of nutritious fruit within South Africa is increased. This research report’s aim is to investigate the effectiveness of a deep learning algorithm for detecting and classifying diseases in lemon orchards using multispectral drone imagery. This entails assessing the performance of a pretrained ResNet-101 model, fine-tuned with additional sample images, in accurately identifying and classifying diseased lemon trees, specifically those affected by Phytophthora root rot. The methodology involves the utilization of a pretrained ResNet-101 model, a deep learning architecture, and the retraining of its layers with an augmented dataset from multispectral aerial drone images of a lemon orchard. The model is fine-tuned to enhance its ability to discern subtle spectral variations indicative of disease presence. The selection of ResNet-101 is grounded in its proven success in image recognition tasks and transfer learning capabilities. The results obtained demonstrated an impressive accuracy of 80%. The deep learning algorithm exhibited notable performance in distinguishing root rot-affected lemon trees from their healthy counterparts. The findings indicate the promise of utilizing advanced deep learning methods for timely and effective disease detection in agricultural farmlands, facilitating orchard management.
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    Knockdown of long non-coding RNA PANDA improves the cytotoxic effects of cisplatin in oesophageal squamous cell carcinoma cell lines
    (University of the Witwatersrand, Johannesburg, 2024-11) Moonsamy, Sasha Sarasvathee Keshnee; Mavri-Damelin, Demetra; Jivan, Rupal
    Oesophageal cancer is one of the leading causes of cancer death worldwide, of which oesophageal squamous cell carcinoma (OSCC) is the major subtype in southern and eastern Africa. Cisplatin is a well-established drug used to treat multiple cancers, including OSCC. Drug resistance is a major impediment to continued cisplatin therapy in numerous cancers. LncRNA P21-associated non-coding RNA DNA damaged activated RNA (PANDA) is known to function in cell cycle regulation in response to DNA damage and is upregulated in OSCC. We aim to determine lncRNA PANDA expression in South African-derived OSCC cells and establish whether down-regulation of this lncRNA can be used to supplement cisplatin therapy. In this study, MTT assays were performed to determine the EC50 concentrations of cisplatin in OSCC (WHCO1, WHCO5, and SNO) cells and HEK293 cells as a non-cancer control. The cytotoxic effects of cisplatin were exerted in all cell lines, with WHCO5 and SNO appearing more responsive to cisplatin than WHCO1 and HEK293. RT-PCR was used to detect if lncRNA PANDA is expressed in untreated and cisplatin-treated cells and was detected in all cell lines. Knockdown of lncRNA PANDA by siRNA was assessed with RT-PCR. Phase contrast microscopy was used to assess whether siRNA reagents altered cell morphology at 5, 24, and 48 hours post treatment. No significant alterations in cell morphology were observed in WHCO1, WHCO5, SNO, and HEK293 cells. MTT assay evaluation after 48 hours of cisplatin exposure, with or without siRNA for lncRNA PANDA, showed a significant reduction in EC50 concentrations in WHCO5, SNO, and HEK293 cell lines, suggesting that knockdown of lncRNA PANDA may improve cisplatin cytotoxicity in some cell lines. However, the EC50 values were higher with lncRNA PANDA knockdown in the WHCO1 cell line, suggesting that not all OSCC cell types may be responsive to this approach. In conclusion, lncRNA PANDA is expressed in response to cisplatin-induced DNA damage, and the down regulation of lncRNA PANDA improves the cytotoxic effects of cisplatin; however, further investigations are warranted in OSCC.
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    An exploration of Business Studies Teachers' integration of Information and Communication Technologies to equip Grade 12 learners with critical business skills
    (University of the Witwatersrand, Johannesburg, 2024) Gcabanshe, Nduduzo Brian; Ndlovu, Nokulunga Sithabile
    Business studies is a subject that in South African schools to equip learners with skills that would enable them to operate effectively in contemporary business environment, either as employers or employees. However,there is a general concern that learners who are produced by these schools do not possess skills that are relevant to current business environments. This is partly due to the impact of technological developments that continue to cause a shift in skills needed by businesses. Therefore, there is a need for an exploration on how best business studies teachers integrate ICTs in their classrooms to equip learners with skills that are required by the contemporary business environment. This study explored ICT integration by business studies teachers to equip Grade 12 learners with critical business skills that are required by the contemporary business environment. Social Constructivism Theory and Functional Context Theory were adopted as the theoretical lenses of this study. Social Constructivists emphasize the need for interaction, collaboration, active learning, and autonomous learning in the learning context for meaningful learning to occur. Functional Context Theory, on the other hand, advocates for a learning environment that reflects the world for which learners are being prepared for. The proponents of this theory advise teachers to integrate resources that learners would use upon joining the real world of work. This is a qualitative study underpinned by the interpretive research paradigm. A multi case study research design was deemed suitable for this particular study. Face-to- face individual interviews and classroom observations were adopted to collect data. Six Business Studies teachers who use ICTs to teach were selected from six secondary schools located in Kwa-Zulu Natal province of South Africa were iv purposively sampled. Data that was collected were analyzed using hybrid thematic analysis. Findings of the study were that: i. teachers see value in ICT integration in their business studies pedagogical practices. teachers see ICTs as tools that assist in exposing learners to authentic learning activities that help them to acquire critical business skills needed by the contemporary business environment. business studies teachers adopted various learner-centred teaching methods to create learning environments that promote the acquisition of critical business skills. iv. most teachers integrated different ICTs to nurture learners’ critical business skills. teachers mainly relied on their personal teaching experiences and their generic technological skills. Based on the findings of this study, Technology Integration Model for Business Studies teachers was developed. The developed framework can play a role in helping business studies teachers integrate ICTs in a systematic way that would lead to learners’ acquisition of critical business skills. Based on the key findings highlighted above, the study recommends that the Department of Basic Education (DBE) should develop coherent professional development programmes to expose all business studies teachers to novel pedagogies, learning activities and ICTs that can be used to nurture learners’ critical v business skills. This will help to reduce teachers’ over reliance on their teaching experiences and what they think is suitable for learners to acquire critical business skills, which sometimes can be inconsistent with the objectives of the business studies curriculum.
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    Novel antiangiogenic peptide targeted therapeutic nanosystem for non-small-cell lung carcinoma
    (University of the Witwatersrand, Johannesburg, 2023) Ngema, Lindokuhle Malibongwe; Choonara, Yahya Essop; Marimuthu, Thashree; Adeyemi, Adebawole
    Lung cancer is the leading cause of cancer deaths globally, with nearly 1.8 million deaths and 2.2 million incidences recorded annually. Primarily, non-small-cell lung carcinoma (NSCLC) is the most commonly diagnosed type of lung cancer, which makes up approximately 85% of all reported lung cancer cases. Currently, the management of NSCLC is a global challenge, and although, various treatment protocols are available, such as surgery, radiotherapy, and chemotherapy, the survival outcomes remain poor. Combination chemotherapy is the current first-line treatment for NSCLC, however, it presents with a myriad of drawbacks, including non-specificity, high dosage, and detrimental side effects, resulting in patients intolerability to the regimen. Consequently, a new therapeutic approach is greatly needed and warrants the design of biocompatible targeted drug delivery nanosystems that can halt tumor proliferation and metastasis by targeting key molecules and deliver drugs directly to tumors, with limited side effects and toxicity to healthy cells. Tumor targeted drug delivery nanosystems such as magnetic nanoparticles (MNPs) modified with biomolecules and functionalized with homing peptides are of great interest for potential application as a potent nanomedicine in NSCLC management. Accordingly, the present study set to develop novel targeted paclitaxel (PTX) delivery nanosystems from the amenable superparamagnetic iron oxide nanoparticles (SPIONs) coated with trans-10,cis-12 conjugated linoleic acid (10E, 12Z) and functionalized with either a vascular endothelial growth factor receptor (VEGFR) binding or a matrix metalloproteinase 2 (MMP-2) binding peptide, for specific delivery of PTX to VEGFR and MMP-2 expressing NSCLC tumors. A preceding nanosystem without the peptides (CLA-coated PTX-SPIONs) was originally fabricated as proof of concept for the application of 10E, 12Z CLA as a surface coating and drug partitioning biomolecule. CLA-coated PTX-SPIONs exhibited a spherical shape, with an average particle size and zeta potential of 96.5 ± 0.6 nm and −27.3 ± 1.9 mV, respectively. The nanosystem had a drug loading efficiency of 98.5% and demonstrated a sustained site-specific in vitro release of PTX over 24 h (i.e., 94% at pH 6.8 mimicking the tumor microenvironment). Enhanced anti-proliferative activity was also observed with the CLA-coated PTX-SPIONs against a lung adenocarcinoma (A549) cell line after 72 h, with a recorded cell viability of 17.1%. Thereafter, the fabricated nanosystem was optimised for direct tumor-targeting by functionalization with HRH or CTT peptides, to give CLA-coated PTX-SPIONs@HRH and CLA-coated PTX-SPIONs@CTT. A new design methodology was established for the tandem surface functionalization of CLA-coated PTX-SPIONs with the antiangiogenic peptides, via coupling reactions. A series of robust nanotechnological techniques were employed for pertinent physicochemical characterization, in vitro evaluation of drug release, anti-proliferative activity, and quantification of VEGF-A and MMP-2 levels. Meanwhile, in vivo testing was carried out on a lung tumor xenograft mouse model. Both nanosystems exhibited a marked cellular uptake and internalization by A549 cells, and CLA-coated PTX-SPIONs@HRH significantly reduced secretion levels of VEGF-A in human dermal microvascular endothelial cells (HMEC-1) from 46.9 pg/mL to 35.6 pg/mL, meanwhile CLA-coated PTX-SPIONs@CTT significantly inhibited MMP-2 secretion by almost 70% , indicating specific anti-MMP-2 activity. A 76.6% and 69.7 % tumor regression was observed in a lung tumor xenograft mouse model treated with CLA-coated PTX SPIONS@HRH and CLA-coated PTX-SPIONs@CTT, respectively, demonstrating tumor targetability and angiogenesis inhibition. Lastly, the pharmacokinetics (PK) evaluation revealed that both nanosystems prolonged the half-life of PTX and circulation time in vivo. In essence, potent antiangiogenic tumor-targeted PTX delivery nanosystems were successfully fabricated, and the obtained results suggest potential application of CLA-coated PTX SPIONs@HRH and CLA-coated PTX-SPIONs@CTT for effective management of NSCLC.
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    Using Mnemonic and Sub-lexic Reinforcement Techniques to Enhance Reading Abilities among Grade Three Learners with Dyslexia in Primary Schools in Mpumalanga: Analysis of Age and Gender Differences
    (University of the Witwatersrand, Johannesburg, 2024) Zindoga, Lilian; Aloka,Peter
    Learners with dyslexia (LWD) have difficulties in accurate and fluent word recognition and poor spelling and decoding abilities. Such learners also face challenges in various areas. In addition, dyslexia is linked with experiences of stigmatization and lowered self- concept. However, every learner in the society including those with dyslexia who have been excluded from the formal education system, must get access to quality education without discrimination. In South Africa, White Paper 6 outlines a national strategy for systematically addressing and removing barriers to learning through establishing full- service schools, converting special schools into resource centres, training education managers and teachers, and developing institutional and district support structures and pursuing a funding strategy. However, several studies report that LWD are still many and disadvantaged in the inclusive school set-ups. LWD continue to face academic, social, and psychological challenges in school and therefore early interventions are crucial for the development of these learners. This study aimed to examine effectiveness of mnemonic and sub-lexical reinforcement techniques in enhancing reading abilities among grade three LWD in two public schools in Mpumalanga, South Africa and was guided by two theories: Skinner’s reinforcement theory and the Information Processing Theory (IPT). The study was also informed by the Human Rights Model of Disability and the Inclusive Pedagogical Approach. This study was anchored on pragmatic research paradigm. Within the mixed methods methodology, the Sequential Triangulation design guided the data collection process. The sample size consisted of 43 learners: 23 grade three LWD from the intervention and 20 learners from the control schools. Pre-and post- tests were administered to the learners during the first three months and during the second half of the research period which took 6 months using the quantitative sample of 43 LWD. The initial test was the Bangor Dyslexia test that was administered to all grade three learners from both the experimental and the control schools. The study’s qualitative data, in the form of interviews, was also undertaken in the second phase of the data collection period where 6 parents of LWD were selected using purposive sampling and 3 English Grade three teachers, plus the principal and the deputy principal underwent semi- structured in-depth interviews. The research tools used were reading tests, short reading comprehension passage, questionnaires, and interview guides. Validity of questionnaires was ensured by Keyser Meyer Oklin test while reliability was ascertained by use of xv Cronbach’s alpha. Quantitative data were analyzed using both descriptive and inferential statistics whereas the qualitative data was analyzed using thematic analysis. The study findings indicated that the use of mnemonic reinforcement techniques to enhance reading abilities among grade three learners with dyslexia in primary schools is highly effective. The findings further revealed that repeated reading as a form of sub- lexical reinforcement techniques is effective in enhancing reading abilities among learners with dyslexia. The findings also revealed that there is a significant effect of gender in influencing enhancement of reading performance by mnemonic intervention, with the female learners having better scores than males. The findings indicated that girls had comparatively higher improvement in performance than the boys in the two components of reading ability (reading and comprehension) and in the overall reading ability, after having gone through sub-lexical intervention. The findings further indicated that generally older children in the intervention group had relatively higher improvement in performance in overall reading ability and its two components (reading and comprehension) than the younger children in same group. The findings indicated that there was statistically significant difference in reading scores between younger and older children among grade three LWD who received sub-lexical treatment, with older learners having higher scores than younger learners. The study recommends that the Department of Basic Education should revise the policy that reading is tested from grade one, instead of from grade three, and that those who are not able to read do not proceed until and unless they are able to read. Moreover, the Department of Basic Education should organize workshops that train teachers in various approaches on how to improve reading of learners with reading problems because the workshops would help teachers by equipping them with the most widely used approaches to reading instruction to enhance learners’ reading abilities of learners in early years.
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    Family-based adverse childhood experiences as a determinant of learner drug abuse in Soweto high schools: implications for early intervention
    (University of the Witwatersrand, Johannesburg, 2024) Mnyamana, Nzukiso Theophillus; Aloka, Peter
    Drug abuse is the excessive, maladaptive, or addicted use of drugs for purposes other than those prescribed by a doctor, even if this usage may lead to social, psychological, and physical issues. Learners who abuse drugs have a higher risk of developing mental health issues, such as depression, conduct issues, personality disorders, suicidal ideation, attempted suicide, and suicide, than learners who do not. Resounding evidence suggests that despite all the restrictions put in place by schools regarding substance abuse, it is nevertheless pervasive on school grounds in the Soweto region. It has been reported that alcohol, tobacco, and hallucinogens are the most often used drugs and substances among teenagers in Soweto. Additionally, it has been reported that drug misuse among learners in secondary schools in the Soweto district of South Africa is on the rise. Despite previous research having been done to address drug abuse among learners, there is still very scanty research on the effect of family based adverse childhood experiences. The main goal of this study was to examine the effect and correlation of family based Adverse Childhood Experiences and the escalating learner drug abuse among learners in township High schools in Soweto. The study also looked at the kind of support that are available at home for learners who are involved in drug abuse and early home based intervention strategies that could be adopted to assist learners who abuse drugs. Finally, the study sought to develop a structural equation modelling that can explain the relationship between biographical factors, familial psychological and familial social factors and learner drug abuse. Within the mixed methods research paradigm, concurrent triangulation research design was adopted. Thus, by adopting a mixed methods research methodology, target population comprised 80 High School learners at the selected four Soweto High Schools in Gauteng Central District. For the quantitative phase, 80 High School learners from four Soweto High Schools were obtained using a census sampling technique. A sample size of 16 High School learners was chosen for interviews during the qualitative phase of the study using the purposive sampling method. Parental Behavioral Control Scale, Parent-Child Attachment Patterns Scale, Emotional Breakdown Scale, Induced Psychological Disorders Scale, Parent–Adolescent Relationship Scale, Sibling Influence Scale, Parental Influence Scale and Home Based Support scale were used to collect quantitative vii data from learners. Semi-structured interviews with learners were conducted to gather information for the qualitative phase. The Keyser Meyer Oklin test was used to guarantee the validity of the questionnaires, and Cronbach's alpha was used to determine their reliability. Additionally, the trustworthiness of qualitative data was ensured. The findings of the study indicated that the biographical factors such as family type, family size, parental level of income, and parental level of education had a significant influence on learner drug abuse. Furthermore, familial psychological factors such as cognitive factors, behavioural factors, emotional factors, parental behavioral control, parent-child attachment patterns, emotional breakdown and induced psychological disorders also had a significant influence on drug abuse. Moreover, the study equally revealed familial social factors, such as parent related factors, sibling related factors, and finally, community related factors to have a significant effect on learner drug abuse. The findings also indicated that familial social factors and familial psychological factors were significant predicators of drug use among the learners. Overall, the results revealed that the variables investigated in this study are suitable for use in structural equation for escalating learner drug abuse. In conclusion, the family systems model is appropriate and fit for demonstrating the structural relationship between psychological, social factors and learner drug abuse among High School learners. From the findings aforemetioned, the study proposes a 6-stage intervention Model which could assist learners in High Schools as far as drug abuse is concerned. The study recommends that the school counsellors and management should perform psychological assessment on learners to identify those that are at risk of indulgence in drugs. The psychological assessment on learners to identify those with birth order that are at risk of indulgence in drugs would help them to evaluate their own cognitive, intellectual, and problem-solving abilities so as to counter psychological patterns susceptible to drug abuse. The study recommends that the school management should provide parents with the essential educational support and advice about familial social issues that may have a bearing on learner drug abuse
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    Researching graduate employability and graduate employability skills of non-traditional graduates in Nigeria
    (University of the Witwatersrand, Johannesburg, 2024) Sodeinde, Mojisola; Hutton, Timothy; Ojo, Emmanuel
    The outbreak of the coronavirus disease in 2019 (COVID-19) resulted in the global adoption of strict lockdown protocols implemented to curtail the proliferation of the virus. The Internet emerged as a leading tool for working remotely, e-teaching, online collaboration, gaming, and for video streaming and conferencing. This study aimed to investigate Nigerian employers' perceptions of hiring graduates who received their degrees from non-traditional modes of learning such as e-learning. The global pandemic became a transformational experience that opened the guardrails for innovative ideas on education and instruction, helping to accelerate the use of distance and virtual instructional tools at educational institutions such as universities during the lockdown. COVID-19 has thus changed how people work, teach, and learn worldwide. The over-arching question of this research was: What understanding do employers have of graduate employability and employability skills, and how does the degree delivery mode factor into recruitment decisions in Nigeria? Furthermore, the subsequent sub- questions were formulated to guide the research process: (1) What perceptions do employers have of graduates who obtained their qualification through alternative modes of learning such as online or e-learning? (2) How does the course delivery mode affect employers’ understanding of graduate employability, and employability skills in the Nigerian labour market? (3) What do employers of labour in Nigeria consider as key factors, with respect to competencies of e-learning and traditional classroom graduates, in recruitment decisions? (4) Using the USEM model of employability as an employability framework, how do the four key descriptors measure within the Nigerian labour market? Explanatory sequential mixed methods were utilized in this doctoral research, collecting quantitative data from one hundred and ten (110) Nigerian human resource professionals and collected qualitative data in semi-structured interviews from five (5) human resource professionals. The doctoral study found that Nigerian employers are more concerned with the personal attributes of graduates than they are with the delivery mode for instruction and learning in the academic institution of the graduate. While employers overwhelmingly view e-learning as comparative to the traditional mode of instruction and thus agree that there is tangible difference between the two modes, about half of all employers prefer to recruit graduates from a traditional on-campus mode of learning. iv Using USEM as the conceptual framework for employability and employability skills, personal attributes emerged as the most desirable set of skills for Nigerian employers, more important than subject matter knowledge. The consensus among employers indicates that there is no discernible distinction in the educational achievements between graduates who have completed their academic pursuits through conventional means and those who have opted for the virtual modality.
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    Effectiveness of blended teaching on learning engagement and academic achievement in Organic Chemistry: A case study of South Africa Grade 12 Learners
    (University of the Witwatersrand, Johannesburg, 2024) Chakawodza, Josphine Munyaradzi; Kizito, Rita N.; Nakedi, Mpunki
    Globally, the use of blended teaching has increased tremendously, particularly at university level. However, there is a dearth of research on the use of blended teaching at high school level and in a developing nation, as well as on the efficacy of blended teaching at high schools, particularly those that are least advantaged. These under-resourced schools where traditional face-to-face teaching is prevalent, cater for the largest learner cohort in South Africa. This study focused on Organic Chemistry, a Physical Sciences topic which most South African learners generally find difficult resulting in poor academic achievement. All this requires that innovative teaching methods be employed. When designed effectively, blended teaching comes with several benefits, such as catering for learner diversity, self-directedness, and flexibility, thereby increasing learning gains (Armellini & Rodriguez, 2021, Halverson & Graham, 2019). The main aim of this study was to determine the effectiveness of blended teaching in developing learning engagement and academic achievement in Organic Chemistry in Grade 12 learners at one of the least advantaged High schools of South Africa. A mixed method approach in the form of sequential explanatory design was utilised. Two existing groups (resembling quasi experimental design in which the subgroup sample assignment depicted elements of random sampling), one experimental (n=100), and another control (n=100), comprising Grade 12 Physical Sciences learners from one school participated in this study. Quantitative data collected through surveys and Organic Chemistry test were analysed using descriptive and inferential statistics as well as moderated regression analysis while qualitative data (interview data from six boys, six girls, and two teachers) were analysed using thematic, content, and comparative analyses. This showed that blended teaching was significantly more effective in developing learning engagement and improving academic achievement in Organic Chemistry. It was concluded that the ‘blend’ used in this study was effective for the broader South African high school context. Additionally, two out of three learning engagement sub-constructs had significant moderating effects on the relationship between blended (or traditional face-to-face) teaching and academic achievement while the third one did not.
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    Optimising laboratory-rearing parameters for anopheles funestus to enhance scalability toward the sterile insect technique
    (University of the Witwatersrand, Johannesburg, 2023-11) Niain’ny Felamboahangy, Lalasoa; Koekemoer, Lizette; Munhenga, Givemore; Kaiser, Maria
    The plateauing of gains in the fight against malaria, partly due to insecticide resistance in malaria vector mosquitoes, is a threat to malaria control. Additional vector control tools like the sterile insect technique (SIT) are being evaluated. Anopheles funestus, a main malaria vector in Africa, has not yet been evaluated for control using SIT partly due to difficulties in its colonisation. To proceed with SIT for this species, knowledge of their optimal laboratory-rearing conditions is critical. To optimise An. funestus laboratory-rearing conditions, this study investigated the effect of using an artificial blood-feeding system or anaesthetised guinea pig on fecundity and fertility. Different larval diet doses and larval rearing densities were determined using a life-table approach. Finally, a range of irradiation doses were used to determine the optimal dose which induces sterility in An. funestus males without impacting the ability of the sterile males’ to compete with fertile males to mate with fertile females. Subsequently, mating competitiveness under laboratory conditions of An. funestus males irradiated at 120 Gy across three different ratios of fertile: irradiated males were performed. Results showed that fecundity was three times higher in females blood-fed on anaesthetised guinea pig compared to those blood-fed on the artificial blood-feeding system using bovine blood. Increasing the blood-meal frequency using the artificial blood-feeding system increased egg production, although it was not statistically significant. There were no significant differences between the egg fertility from females that fed on guinea pig or those fed on the artificial blood-feeding system using bovine blood. Anopheles funestus larvae fed with a food dose of 0.04 mg/larva and reared at a density of 0.48 larvae/cm2 resulted in optimal developmental time and pupal production. Furthermore, irradiation of male pupae at different doses did not affect adult emergence regardless of the dose used, however, it correlated negatively with longevity and fertility. Irradiation at doses greater than 100 Gy resulted in a significant difference in both fecundity and fertility. The average mating competitiveness value of An. funestus males irradiated at 120 Gy was 1.24, decreased from 2.63 to 0.27 for different ratios of sterile male: fertile male: fertile female 1:1:1 to 3:1:1. In conclusion, these findings can be used to improve the rearing of An. funestus under laboratory conditions, improving evaluations for SIT. Feeding defibrinated bovine blood through an artificial system will reduce the dependency on live animals for blood-feeding. Optimised larval feeding and rearing density will reduce developmental time and ensure maximal pupal production. An irradiation dose of 100 Gy can be used to induce sterility of An. funestus without significantly affecting mating competitiveness.
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    Investigating how teacher educators create opportunities for preservice teachers to learn biology
    (University of the Witwatersrand, Johannesburg, 2024) Thomas, Naomi; Nyamupangedengu, Eunice; Msimanga, Audrey
    This study explored the opportunities created by four teacher educators in a teacher education programme to bring about meaningful learning. The study sought to understand the complex communicative approaches employed by teacher educators to provide preservice teachers with a platform for engagement with biology concepts in large lecture settings. A case study methodology was adopted for the study. The main purpose of this research was to find out how teacher educators can promote productive discussion and learning experiences in their lectures when teaching selected biology topics. Data sources involved observations of lessons taught by four biology teacher educators in 2017 and 2018 and individual interviews on teacher educators’ teaching practices. To generate data for my study I observed four teacher educators teaching four different topics: population ecology, environmental studies, cell biology, and biochemistry of respiration. A total of fifteen lessons were observed and audio recorded. Data were analysed using the opportunities for the learning model. Results yielded eighteen categories of opportunities provided by teacher educators in their lectures. Findings suggest that teacher educators’ lectures were interactive with a varying spread of elaborative prompts and probing that is supportive of preservice teachers’ cognitive engagement with biology content. I discussed opportunities created by educators in their lecture spaces with a large student population and its implication for teacher education.