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An investigation of students’ approaches to solving problems using equations of motion
No full textThe purpose of this research study is to investigate how to address the under-preparedness of students entering first year physics in South African universities, particularly with regard to their competence in solving kinematics problems. Previous studies show that the best tool for changing and expanding the conceptual understanding of a learner is problem solving; it assists a learner in dealing with new and unfamiliar concepts. These studies have also shown that cooperative learning helps students to share knowledge with each other. This research study thus investigated students’ perceptions of approaches in solving kinematic problems and tasks are examined for the effects of expert problem-solving approaches and cooperative learning on the performance and results obtained by students in first-year mainstream physics at the University of the Western Cape. This process involved profiling students and exploring their problem-solving approaches and performance using prior knowledge and after a teaching and learning focused explicitly on problem-solving. The data was collected by means of surveys and tasks and was analysed using descriptive statistical and qualitative methods. From this study, it can be concluded that cooperative teaching and learning focused on expert problem-solving is necessary in a physics course to address students’ under-preparedness in their first year at university. In addition, it is recommended that lecturers encourage students to use problem solving when tackling any physics problems
A particularly urban disease : the impact of COVID-19 on internal migrants in Cape Town and Johannesburg, South Africa
No full textThis chapter explores the disproportionate impact of COVID-19 on internal migrants in the urban centres of Cape Town and Johannesburg, South Africa. Focusing on the socio-economic and livelihood challenges faced by this population, the research utilizes a survey conducted in 2023 to investigate how the pandemic exacerbated existing vulnerabilities. Results highlight significant disruptions in employment, increased economic hardship, and heightened health risks among migrants, particularly those living in low-income neighbourhoods. Despite the hardships, very few migrants intended to permanently return to their rural origins, indicating a complex interplay between economic necessity and pandemic-induced constraints. The findings underscore the unique challenges faced by internal migrants during health crises and suggest the need for targeted policy interventions to address the specific needs of this group within urban pandemic responses
Qualitative insights into employee motivation during crisis periods, such as the coronavirus disease 2019 pandemic: a case study at a retail organisation in the Western Cape
No full textIn the face of the global challenges posed by the coronavirus disease 2019 pandemic (COVID- 19), employee motivation emerged as a cornerstone of organisational resilience and sustainability. This mini-thesis explores the intricacies of employee motivation within a crisis context, focusing on an optical retail organisation in the Western Cape province of South Africa. The theoretical framework guiding this exploration is Albert Bandura's (1986) Social Cognitive Theory (SCT), which offers a lens through which to analyse the cognitive, behavioural and environmental factors influencing employee motivation during the COVID- 19 pandemic. Guided by Albert Bandura’s SCT, the study examines the interplay of cognitive, behavioural and environmental factors shaping motivation during unprecedented times. The research aims to illuminate how tailored motivational strategies can sustain workforce engagement and organisational effectiveness amid adversity. The study addresses the primary question: “What employee motivation techniques are effective during crises such as the COVID-19 pandemic?” Four objectives were pursued: (1) Investigate what motivation approaches managers can apply to motivate AODs in a time of crisis; (2) Assess the strategic objectives of an optical retail organisation in the Western Cape during the COVID-19 pandemic; (3) Examine the congruence between the motivational needs of the AODs and the goals of the organisation during the COVID-19 pandemic; and (4) Make recommendations to human resource personnel and managers about motivation techniques that are relevant for the achievement of the organisation’s objectives during a crisis like the COVID-19 pandemic. Adopting a qualitative methodology, the research utilised a case study approach, with data collected through semi-structured interviews involving 18 participants, encompassing both AODs and managers. Thematic analysis revealed distinct motivational factors for the two groups. For AODs, key themes included the role of rewards and recognition in motivation, autonomy and control over work, and the impact of work environment and communication. Managers highlighted the role of leadership and management, work-life balance and flexibility, and adaptation and motivation. This study contributes to understanding motivation during crises, offering practical recommendations for human resource management and leadership. Future research is iii encouraged to explore the long-term implications of these findings across diverse contexts and industries
Detecting local and integrated relativistic effects by multi-tracing a single galaxy population in harmonic space
No full textMeasuring relativistic effects on cosmological scales would provide further confirmation of the validity of general relativity in the still poorly tested condition of weak gravity. Despite their relevance, relativistic imprints in the distribution of galaxies on large scales have so far eluded detection, mainly because they are stronger on the largest cosmic scales, which are plagued by cosmic variance. Expanding on previous works, we study galaxy clustering by subdividing a galaxy population into two sub-samples – bright and faint – and we here focus on their two-point correlation function in harmonic space, i.e. via the angular power spectrum. Thanks to such a split in magnitude and by exploiting the multi-tracer technique, we are able to boost the impact of the relativistic contributions. We first focus on the leading relativistic contribution given by the Doppler effect and show that, with a carefully tailored luminosity cut, it can be detected. Then, we look at the sub-dominant effects predicted by general relativity and quantify how their statistical significance, as yet undetectable, varies with redshift binning and survey specifications. As case studies, we consider in our forecasts a bright galaxy sample at low redshift, an Hα emission-line galaxy survey at intermediate redshifts, and high-redshift Lyman-break galaxies at high redshift
Long-read de novo assembly of the spekboom (Portulacaria afra) genome
No full textPortulacaria afra (P. afra), or Spekboom as it is locally known, is a versatile evergreen shrubby succulent plant in the family Didiereaceae and endemic to the south-eastern parts of southern Africa. P. afra is not only known for its nutritional composition and its medicinal properties but has been shown to be pivotal in preventing desertification through limiting soil degradation. In addition, there is currently growing global attention on the use of P. afra as a garden ornamental. To address the lack of genetic resources for this increasingly important plant, we report on the de novo genome assembly of a Spekboom specimen of the Albany Thicket Biome using Oxford Nanopore Technology long-read sequencing, coupled with Illumina short-read polishing. Flow cytometry and k-mer analysis revealed the genome to be tetraploid and supports a haploid assembly size of ~ 0.68 Gb. BUSCO analysis revealed 99.3% complete BUSCO genes, indicative of the high gene completeness of the assembled genom
Population pharmacokinetics of ethionamide and ethionamide sulfoxide in patients with multidrug-resistant tuberculosis
No full textTuberculosis (TB) remains an infectious disease worldwide and the leading killer of people living with HIV; yet it is curable. One of the challenges faced in TB therapy is the resistance of Mycobacterium tuberculosis to antituberculosis drugs, leading to drug-resistant tuberculosis (DR-TB). Various types of DR-TB resulted from antimicrobial resistance; up-to date, multidrug-resistant tuberculosis (MDR-TB) is the predominant type of DR-TB, thus the focus of the current study. MDR-TB developed following resistance of the Mycobacterium tuberculosis to rifampicin and isoniazid, which are the two most potent first-line antituberculosis drugs. It is currently treated with a choice of regimens: a short, all-oral 6-month regimen, a 9-month all-oral regimen containing ethionamide, and longer individualized regimens. Ethionamide needs to be activated by mycobacterial enzymes to exert its antimicrobial activity. Ethionamide sulfoxide, its active metabolite, displays a similar or greater activity against Mycobacterium tuberculosis; yet there is limited pharmacokinetic literature on ethionamide sulfoxide, unlike ethionamide which has been studied for more than five decades.
This study aimed at determining the population pharmacokinetics of ethionamide and ethionamide sulfoxide, assessing the effect of HIV status, antiretroviral drugs, age, weight, gender, and renal and hepatic functions on their respective pharmacokinetic parameters. The study also aimed at determining the amount of ethionamide sulfoxide that emanated from ethionamide metabolism in the body.
Methods: After signing an informed written consent, male and female patients with MDR- TB, co-infected or not with HIV, who were on treatment for at least two weeks at Brewelskloof Hospital (Western Cape, South Africa), were involved in the study. On the day of the study, after an 8-hour overnight fast, each patient received his/her medications, including 500 mg or 750 mg dose of ethionamide as determined by the doctor in charge. Blood samples were collected at baseline and 1, 2, 2.5, 3, 3.5, 4, 5, 8 and 24 h post drug administration. Using a developed and validated ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS), ethionamide and ethionamide sulfoxide were simultaneously quantified in patients’ plasma. Ethionamide and ethionamide sulfoxide pharmacokinetic parameters were first determined through non-compartmental analysis (NCA) using PKanalix2023R1 and compared
Machine-learning approaches for classifying star-forming galaxies and active galactic nuclei from MIGHTEE-detected radio sources in the COSMOS field
No full textRadio synchrotron emission originates from both massive star formation and black hole accretion, two processes that drive galaxy evolution. Efficient classification of sources dominated by either process is therefore essential for fully exploiting deep, wide-field extragalactic radio continuum surveys. In this study, we implement, optimize, and compare five widely used supervised machine-learning (ML) algorithms to classify radio sources detected in the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE)-COSMOS survey as star-forming galaxies (SFGs) and active galactic nuclei (AGNs). Training and test sets are constructed from conventionally classified MIGHTEE-COSMOS sources, and 18 physical parameters of the MIGHTEE-detected sources are evaluated as input features. As anticipated, our feature analyses rank the five parameters used in conventional classification as the most effective: the infrared–radio correlation parameter (), the optical compactness morphology parameter (class_star), stellar mass, and two combined mid-infrared colours. By optimizing the ML models with these selected features and testing classifiers across various feature combinations, we find that model performance generally improves as additional features are incorporated. Overall, all five algorithms yield an F1-score (the harmonic mean of precision and recall) >90 per cent even when trained on only 20 per cent of the data set. Among them, the distance-based k-nearest neighbours classifier demonstrates the highest accuracy and stability, establishing it as a robust and effective method for classifying SFGs and AGNs in upcoming large radio continuum surveys
Green synthesis of gold and silver nanoparticles from Harpagophytum procumbens (Devil’s Claw) extract and their biomedical applications.
No full textNanotechnology refers to the research of materials with dimensions of one billionth of a meter (1-100 nm). Metallic nanoparticles (MNPs), such as gold (Au) and silver (Ag), are undoubtedly some of the most popular nanoparticles (NPs) owing to their physicochemical properties. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) have antibacterial and anticancer properties which allows them to be used in various biomedical applications. Green synthesis
of MNPs is a safe, cost-effective, and sustainable method that mitigates against highly toxic chemicals and the formation of dangerous byproducts seen in most physical and chemical methods. Plant extracts contain phytochemicals, which act as reducing and stabilising agents in the synthesis of NPs. Harpagophytum procumbens subsp. procumbens (Burch.) DC. Ex Meisn, commonly known as Devil's Claw, is a weedy perennial tuberous plant native to the Kalahari region in southern Africa. Its secondary bioactive compounds have been identified, including amino acids, carbohydrates, iridoids, flavonoids, and phytosterols. The therapeutic effects of Harpagophytum procumbens (Hp) are attributed to iridoid glycoside, harpagoside, compound found in high concentrations in Harpagophytum species that is responsible for its anti-inflammatory activity. In addition, research has reported the analgesic, antioxidant, anti- microbial, anti-cancer and anti-viral effects of Hp. In the current study, Harpagophytum procumbens aqueous extracts (HpAE) was used for the green synthesis of AuNPs and AgNPs. Various parameters such as pH, temperature, extract concentration, metal precursor concentration, ratio and synthesis reaction time were investigated to determine the optimal conditions for HpAE-MNP synthesis. Due to the biocompatibility and well-defined surface chemistry of AuNPs, ciprofloxacin (CIP) was
functionalized onto the surface of HpAE-AuNPs for use in drug delivery and as a therapeutic agent. The green synthesized HpAE-MNPs further characterized using UV-vis spectroscopy (UV-vis), Dynamic Light Scattering (DLS), Zeta (ζ) potential, Fourier-transform Infrared (FTIR), Induced Coupled Plasma-Optical Emission Spectrometry (ICP-OES), and High transmission electron microscopy (HR-TEM). The stability of HpAE-MNPs were evaluated in various biological media, including deionized water (ddH2O), Müeller-Hinton broth (MHB), Phosphate-buffered saline (PBS), complete and incomplete Dulbecco's Modified Eagle's Medium (DMEM). Agar well diffusion and microdilution assays were used to investigate the antibacterial activities of HpAE and HpAE-MNPs against several bacterial strains associated with antimicrobial resistance (AMR) (Escherichia coli, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Klebsiellae pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa and Escherichia cloacae). In addition, the antioxidant potential of HpAE and HpAE-MNPs were evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH),
2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and Ferric-Reducing Antioxidant Power (FRAP) assays. The HpAE-AuNPs had a SPR peak at 540 nm, a hydrodynamic diameter of 148.47 ± 29.4 nm, an average core size of 96.2 ± 38.2 nm (prisms), 40.02 ± 8.2 nm (pentagons), 33.46 ± 9.5 nm (hexagons) and 43.55 ± 12.4 nm (irregular spheres). Upon functionalization, HpAE-AuNPCIPs displayed a reduced hydrodynamic diameter of 134.85 ± 27.29 nm and an increased average core size of 104.27 ± 21.18 nm (prisms), 99.63 ± 17.68 nm (pentagons), 85.67 ± 10.27 nm (hexagons) and 74.35 ± 21.45 nm (irregular spheres). On the other hand, HpAE-AgNPs had a SPR peak at 404 nm, a hydrodynamic diameter of 45.71 ± 4.84 nm, and an average core size of 27.55 ± 7.99 nm. The HpAE-AuNP had a polydispersity index (PDI) of 0.5 ± 0.03 and a ζ potential of -16.97 ± 0.49 mV, while HpAE-AuNPCIPs had a PDI of 0.32 ± 0.12 and a ζ potential of -33.39 ± 2.84 mV. The HpAE-AgNPs had a PDI of 0.24 ± 0.07 and a ζ potential of -23.5 ± 3.5 mV. Both HpAE-AuNPs and HpAE-AuNPCIPs were larger and anisotropic in comparison to smaller spherical HPAE-AgNPs. HpAE-MNPs were determined to have high phenolic and flavonoid content, suggesting the involvement of phytochemicals in the reduction and capping of metal ions during the synthesis process. HpAE-AgNPs exhibited dose-
dependent and enhanced free radical scavenging activity, while HpAE-AuNPs displayed limited antioxidant activity. The HpAE-AgNPs exhibited broad-spectrum antibacterial effects against both Gram-positive and Gram-negative antimicrobial resistant bacteria, with higher susceptibility observed against Gram-negative bacteria. HpAE-AuNPs alone were non-toxic to the tested bacteria, however, enhanced antibacterial activity against Gram-negative bacteria
were only observed after functionalization of HpAE-AuNPs with CIP. Therefore, the biosynthesized HpAE-AgNPs and HpAE-AuNPCIPs provide potential alternatives for treating ESKAPE infections and subsequently AMR, while HpAE-AgNPs show promise as antioxidants to manage oxidative stress-related conditions
Euclid: the early release observations lens search experiment
No full textWe investigated the ability of the Euclid telescope to detect galaxy-scale gravitational lenses. To do so, we performed a systematic visual inspection of the 0.7 deg2 Euclid Early Release Observations data towards the Perseus cluster using both the high-resolution IE band and the lower-resolution YE, JE, and HE bands. Each extended source brighter than magnitude 23 in IE was inspected by 41 expert human classifiers. This amounts to 12 086 stamps of 1000 × 1000. We found 3 grade A and 13 grade B candidates. We assessed the validity of these 16 candidates by modelling them and checking that they are consistent with a single source lensed by a plausible mass distribution. Five of the candidates pass this check, five others are rejected by the modelling, and six are inconclusive. Extrapolating from the five successfully modelled candidates, we infer that the full 14 000 deg2 of the Euclid Wide Survey should contain 100 000+-7030000000 galaxy-galaxy lenses that are both discoverable through visual inspection and have valid lens models. This is consistent with theoretical forecasts of 170 000 discoverable galaxy-galaxy lenses in Euclid. Our five modelled lenses have Einstein radii in the range 000 . 68 < θE < 100 . 24, but their Einstein radius distribution is on the higher side when compared to theoretical forecasts. This suggests that our methodology is likely missing small-Einstein-radius systems. Whilst it is implausible to visually inspect the full Euclid dataset, our results corroborate the promise that Euclid will ultimately deliver a sample of around 105 galaxy-scale lenses
Quality midwifery care during childbirth at a midwife obstetric unit: a qualitative study
No full textBackground: Globally, there is an increasing focus on enhancing the quality of midwifery care. In public institutions, primary care midwifery is provided at a midwife obstetric unit (MOU). Midwives at MOUs are the first contact that pregnant women have when accessing midwifery care. There exists a notable disparity in the perception of quality midwifery care between midwives and women. In South Africa, there has been a scarcity of research examining the perspectives of midwives and women, regarding the quality of midwifery care provided during childbirth. Objectives: The objective of this study was to explore and describe women’s and midwives’ perceptions of the quality of midwifery care during childbirth, at a MOU in Cape Town in the Western Cape, South Africa. Method: A qualitative exploratory descriptive design was utilised. Four women and five midwives were selected through purposive sampling. Semi-structured interviews were undertaken, transcribed and analysed utilising Tesch’s eight-step approach to qualitative data analysis. Results: Three themes emerged: (1) understanding of quality midwifery care, (2) experiences of women during childbirth and (3) support received by women and midwives. Conclusion: The quality of midwifery care remains compromised within the MOU setting due to various challenges encompassing limitations of both human and physical resources. It is imperative to establish a shared understanding of what constitutes quality midwifery care, as women and midwives often perceive it differently. Contribution: Midwifery care during childbirth requires the engagement of all stakeholders, including women, to enhance the quality of midwifery care provided