DSpace Repository

Welcome to the NWU Repository, the open access Institutional Repository of the North-West University (NWU-IR). This is a digital archive that collects, preserves and distributes research material created by members of NWU. The aim of the NWU-IR is to increase the visibility, availability and impact of the research output of the North-West University through Open Access, search engine indexing and harvesting by several initiatives.

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Development of a strategic guideline to design an intelligence instrument applicable to South African school learners: A multi-method exploration
(2024) Van der Merwe, Ilze.
Considering formal intelligence assessment instruments currently applied to South African school learners, characterised as a multicultural and multilingual population, and residing and schooled in multidiverse contexts, the applicability, reliability, validity, and fairness of these instruments have come into question. South African psychologists and psychometrists need to conduct intelligence assessments as part of a battery of assessments, following referrals from parents, guardians, therapists, or schools after observing challenges such as learning difficulties or to guide school learners in their educational careers. Based upon findings from intelligence testing and other forms of data gathered (i.e. interviews, background history taking, other measurements such as scholastic and emotional assessments), practitioners need to appropriately deduce diagnoses and suitable interventions (i.e. placement in a special needs classroom/school, arrangement of concessions for formal testing, referral to therapists or clinicians, and more) that are tailored with the best interest of the school learner in mind. Several legislation and policies have been implemented that guide practitioners in the field of psychometrics to employ professional and ethically correct practices. This implies that practitioners need to conduct intelligence assessments that are fair and reliable by using measurements that are applicable and valid. The South African school learner population is characterised as heterogeneous; the multilingual, multicultural school learners reside and attend schools in contexts that vary in levels of socio-economic stance, acculturation, and quality of education received. In order to conduct intelligence testing that is fair to this multi-ethnic group of school learners, practitioners would need appropriate intelligence measurements and assessment skills. This is where the challenge lies, as there is a shortage of cross-culturally fair intelligence measurements. In addition, if the practitioner does not conduct the assessment in the attempt to prevent unfair testing practices, it would lead to a scenario where the learner may be deprived from the opportunity to receive the needed guidance and help; excluding any child from receiving professional services on the grounds of a demographic element such as cultural or language is against that school learner’s constitutional right to equality and having access to healthcare services. Therefore, this PhD research study has aspired to explore the need for a strategic guideline for practitioners (i.e. psychologists, psychometrists, researchers, and experts in intelligence measurement development/adaptation) to ensure that when intelligence instruments are designed, they are applicable and fair when administered to South African school learners. This PhD research study adopted a multi-method approach, consisting of three phases. Phase 1 (Document 1) entailed conducting a critical review of peer-reviewed scientific literature related to the topic of intelligence assessment instruments applied to South African school learners. Extracted data were analysed qualitatively using the thematic data analysis method, which revealed the following three themes: (i) Applicability of intelligence instruments administered to South African school learners; (ii) Contextual and demographic influences affecting performance on administered intelligence instruments; and (iii) Intellectual measuring instruments related to developmental and cognitive ability levels. Phase 1 concluded by stating that demographic (i.e. language, culture) and contextual (i.e. socio-economic status, quality of educational background) elements could influence the applicability of an intelligence instrument to South African school learners, bringing into question the reliability, validity, and fairness of these instruments. It is therefore important that practitioners in the field of psychometry take these demographic and contextual influences into account before developing or selecting an intelligence instrument to assess school learners in South Africa, as these elements may cause incorrect test results. This could furthermore yield bias in the interpretation and reporting of results, which could lead to inappropriate diagnoses and intervention plans. Phase 2 (Document 2) aimed to explore and describe the experiences of a group of intelligence test developing and adaptation experts as well as psychologists and psychometrists who have administered intelligence assessment instruments to South African school learners in various contexts. The qualitative interpretive description research design was applied. Using an internet-based communication platform, twelve psychologists/psychometrists (n = 12) were interviewed, of which six were also experts (n = 6)in intelligence test development and/or adaptation. Participants represented all nine provinces across South Africa. Four themes emerged after reflexive thematic analysis of recorded data from the semi-structured interviews, namely: Utilised intelligence measurements in the current South African school learner context are not relevant anymore; South African education system is a major issue specifically within lower socio-economic status contexts; Newly or adapted intelligence measures cannot realistically be standardised in the current South African school learner context; and (iv) Key informants’ recommendations from their experiences. From the shared participant experiences in Phase 2, it became clear that currently administered intelligence measurements are unfair, inappropriate, outdated, and unsuitable to South African school learners, specifically when considering their multidiverse demographics and modern, multidimensional contexts at home and school. These influencing elements have the tendency to yield test performance/results that are not representative of the learners’ true performance (especially those receiving lower quality of education at less privileged schools), which could lead to inappropriate diagnoses and intervention plans. These findings suggest a need for practitioners in the psychometric field to have access to intelligence instruments that are applicable and fair to all South African school learners. Phase 3 (Document 3) aimed to develop a strategic guideline which provided information to practitioners in the field of intelligence assessment, on how to design an intelligence assessment instrument that is applicable to South African school learners. This was done by employing a qualitative document analysis through the reflexive thematic analysis on Document 1 (published) and Document 2 (in the process to be published) and combining their findings. The following four themes were identified: (i) Utilised intelligence measurements in current South African school learner context are inapplicable; (ii) Newly or adapted intelligence measures cannot really be standardised in the current South African school learner context; (iii) Current South African education system needs to be taken into consideration; and (iv) Current South African school learner contextual and demographic influences need to be taken into consideration. From these themes, steps were created that form the strategic framework to design applicable intelligence instruments for South African school learners. The steps describe both guidance towards instrument design as well as the manner and context of applying the design itself, since these features function as interrelated entities. In conclusion of Phase 3 it became clear that there exists an essential need for emic, up-to-date, applicable, and fair intelligence measurements to be administered to multidiverse South African school learners. When administering intelligence assessments to South African school learners, practitioners are ethically and legally obligated to conduct practices that are fair and equal to all; it is imperative that they consider the local school learners’ schooling, demographic, and contextual (i.e. socio-economic status, acculturation level) background before developing or selecting intelligence measurements for assessment and subsequent diagnoses and crafting of intervention plans. This Phase and the PhD research study’s developed strategic guideline to design an intelligence instrument suitable for a South African population of school learners, informs on fair assessment measurements and practices that will allow multi-ethnic equalisation and empowerment of both school learners and practitioners.
Exploring opportunities for implementing waste-to-energy projects in the City of Johannesburg Metropolitan Municipality
(North-West University (South Africa), 2024) Radingoana, Nakgwe Donald; Van Niekerk, C.S.; Kruger, L.; ;
This study explores opportunities for implementing waste-to-energy technologies to alleviate the City of Johannesburg’s (CoJ) current waste management challenges as well as the current energy crisis in the country. Globally, untreated, unsafe disposal, and inefficient waste collection have contributed to a waste crisis, while a rapidly increasing world population has increased waste generation, and a higher demand for energy. Waste-to-energy is therefore increasingly viewed as a viable solution to waste management and energy supply challenges. However, South Africa underutilises waste for energy generation. CoJ has initiated the adoption of waste-to-energy projects for electricity, but little progress has been made on the actual implementation. This study therefore investigates the potential for implementing waste-to-energy projects in the CoJ to recommend strategies for successfully enhancing both waste management and energy generation in the city. A qualitative approach was used to conduct the study and semistructured interviews were utilised for collecting primary data. Using purposive sampling, 20 managers and employees in CoJ’s waste management and energy departments were selected. The study found that implementing waste-to-energy projects offers numerous benefits to CoJ, including freeing up landfill space, improving energy supply, and contributing to environmental sustainability. Additionally, the study found that the successful implementation of waste-to-energy projects is complex and hinges on a number of factors, including the availability of human, financial, and technological resources, a supportive regulatory and policy environment, and the participation of all stakeholders. Recommendations include the development of employee skills and competencies and the mobilisation of financial resources through increased focus on public-private partnerships. Management is also encouraged to collaborate with policymakers to revise legislation, regulations, and policies that govern waste management and renewable energy and replace it with supportive legislation and policies. Lastly, management should promote a culture of separation at the source and increase the level of public participation.
Characterising the urinary acylcarnitine and amino acid profiles of patients with HIV/TB co-infection, using LC-MS metabolomics
(North-West University (South Africa), 2024) Pretorius, Charles; Luies, L.; ;
This study comprises a comprehensive investigation of the urinary acylcarnitine and amino acid profiles in patients with HIV, TB, and HIV/TB co-infection using LC-MS metabolomics. It addresses a critical gap in current research by exploring the metabolic interplay in HIV/TB co-infection, a domain less extensively studied compared to the individual effects of HIV and Mtb infection. Recognising the potential of metabolomics in enhancing our understanding of HIV/TB co-infection and its immunological impact on host metabolism, this research aimed to characterise the urinary metabolome of individuals afflicted by these conditions. Such insights are pivotal for developing novel treatments and diagnostic strategies to effectively manage the HIV/TB syndemic. In this pursuit, urine samples from 9 HIV/TB co-infected, 7 HIV-only, and 41 TB-only patients, along with 32 healthy controls, were analysed. The analysis employed three targeted HPLC-MS/MS methods, allowing for the distinct assessment of urinary amino acids using the ChromSystems MassChrom® Amino Acid Analysis kit, as well as acylcarnitines and the tryptophan derivative 5-hydroxyindoleacetic acid (5-HIAA) through newly established and validated methods. The validation of these methods encompassed a thorough evaluation of selectivity, linearity, precision, and accuracy, ensuring the reliability of the findings. The results revealed significant alterations in the amino acid metabolome across all infected cohorts. Notably, there was a marked decrease in tryptophan and glycine levels, coupled with increased saccharopine and hydroxykynurenine levels. Enhanced lysine degradation via the saccharopine pathway was evident in HIV/TB co-infected and TB-only patients, as indicated by a significantly increased saccharopine/lysine ratio. While amino acid levels predominantly decreased in the HIV-only patients, an increase was observed in those with TB-only compared to healthy controls. The co-infected cohort did not exhibit a clear trend, suggesting a complex interplay of metabolic processes in the co-infection state. Although changes in acylcarnitines and 5-HIAA were not statistically significant, there were indications of generally elevated medium-chain acylcarnitines in the TB-only and HIV/TB co-infected cohorts. These findings point towards an altered net protein turnover, inflammation, lipid and amino acid catabolism, and potentially diabetic-like hyperglycaemia in the HIV/TB co-infected state, predominantly driven by Mtb infection. Furthermore, this study lays the groundwork for future research aiming to identify robust disease markers, as it suggests that the effects of HIV and Mtb infection on the amino acid metabolome are attenuated in the co-infected state. Overall, this study not only contributes to a deeper understanding of the metabolic complexities associated with HIV, TB, and their co-infection but also opens new avenues for targeted therapeutic interventions in managing these challenging infectious diseases.
Exploring variability of drought events for the western region of South Africa
(North-West University (South Africa), 2024) Pienaar, Lisa; Piketh, S.J.; Chikoore, H.; Havenga, H.; ;
The occurrence of drought in South Africa is inevitable, as it is a naturally occurring phenomenon. What makes this phenomenon extreme is its creeping nature, which could unravel into prolonged, socio-economic drought. Socio-economic drought imposes the greatest threat to agriculture and the economy. Examples of this type of drought recently (at the time of this study) occurred in the Northern Cape, Western Cape, North West, Free State, and Eastern Cape provinces. Most of these provinces were declared disaster regions because of prolonged drought and/or underwent socio-economic impacts. Parts of these provinces are located in the western region of South Africa, which is the area of interest in this study due to its dry nature. The standardised precipitation evapotranspiration index (SPEI) was used to analyse the potential changes in the drought frequency, duration, and intensity of district municipalities. Those findings were linked to potential changes in vegetation, by examining the normalized difference vegetation index (NDVI) trends. The SPEI was then used to examine future drought events from 2050-2100 using Coupled Model Intercomparison Project (CMIP6) data, which was compared to the data from 1962-2022. The 1962-2022 findings showed that the frequency, duration, and intensity of drought had worsened in all district municipalities in the second half of the study period. During the extensive drought period of 2012-2022, a decrease in the NDVI values is present. Yet, the NDVI trends showed an overall increase in all five provinces, meaning that the worsened drought conditions, observed in the SPEI, did not reflect on the NDVI to the same degree. Only 4/17 district municipalities are predicted to have worsened drought conditions in 2050-2100 in comparison to the 1962-2022 results. Overall, this study provides insight into the intensities, frequencies, and duration of past and future drought events in the district municipalities. This information can enable stakeholders, policymakers, mayors, etc. of the district municipalities to proactively prepare for worsening drought conditions.
Development of a GC-MS/MS organic acid profiling method for abalone samples: challenges and future prospects
(North-West University (South Africa), 2023) Padiachee, Varushka; Lindeque, J.Z.; ;
South African abalone (H.midae) locally known as Perlamoen in South Africa is a marine mollusc that is found on the South African shore-line. Due to overfishing and the high commercial value coupled to this marine mollusc, wild abalone stocks are on a decrease. Abalone farming plays and integral role in the aquaculture industry as it allows for additional resources to be produced, it also takes the pressure of wild abalone stocks. Even though there are many research areas fulfilled in terms of the optimal farming and environmental factors for cultured abalone, there can still be additional factors on a biochemical level which could influence the period abalone takes to reach market size. Previous studies performed by our group, hypothesised that there is an absence of organic acids during hypoxia, therefore it can be hypothesised that abalone do not rely heavily on mitochondrial oxidative phosphorylation for energy production but on alternative energy pathways. Metabolomics is an emerging field that allows for the use of multiple analytical platforms to detect and quantify small molecules such as organic acids. This study aimed to develop a GC-MS/MS organic acid profiling method for abalone samples. To test the best approach, two GC-MS/MS were developed, one used Chemical ionisation (CI) and the other Electron impact (EI). The CI MRM method provided reasonable linearity across the concentration range with most organic acids giving a R2 > 0.9. However, certain organic acids such as Succinate, Malate, Lactate and Oxaloacetate show a decline in their curves, which could possibly be due to poor ionisation from CI, poor extraction, or compound degradation. The determined LOD and LOQs (from the curves) are relatively high, which highlight the issue of sensitivity with this method and CI in general. Overall, the EI method gave unsatisfactory response over the concentration range with less compounds having a R2 > 0.9. Organic acids such as 3-Hydroxybutyric acid, Pyruvate and Lactate also showed low precision at the different concentrations. One of the reasons for this is the low specificity of the EI quantitative transitions which detect inferring compounds / peaks leading to inaccurate peak areas for each concentration. It can be concluded that the method performance of the GC-MS/MS method fitted with CI is more satisfactory than EI, but day-to-day challenges with the CI source hinders further optimisation and use in the routine lab. Future prospects include using alternative derivatisation methods that could improve EI MRM detection and linearity of organic acids and should be considered in future studies. The use of LC-MS/MS can also be explored for the detection and quantification of organic acids in abalone, especially as derivatives which could bridge the negative ionisation problem.