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Robbie and Coline
No full textThis collection contains only two photos both the images are labelled on the back with Robbie and Coline. There is one image of a man with a camera who may be assumed to be the “Robbie” mentioned on the back of the photo, the second image shows a poster with the words “Hamba Kahle Comrade Coline” and an outline of Africa with a women’s face contained within, this women we assume is Coline.
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“I think I know it, but I’m not sure”: how pre-service teachers blend conceptual physics problems into solution frameworks
No full textThe purpose with this study was to investigate the challenges faced by second-year pre-service teachers when integrating conceptual physics problems into solution frameworks. The main goal was to understand the complexities involved in this integration process, specifically exploring how pre-service teachers drew upon different levels of knowledge taxonomy (factual, conceptual, procedural, and metacognitive) and the difficulties they encountered at each level when blending conceptual problems into solution frameworks. By categorising the difficulties encountered into minor (D1), major (D2), and atypical (D3) challenges, I aimed to shed light on the effectiveness of different teaching approaches in addressing these challenges. To evaluate pre-service teacher performance, I employed a pre- and post-test control-group design to compare 2 learning conditions: traditional lecture-based instruction and the SPSE (situation, problem, solution, evaluation) blended model in a 6-week advanced physics course for pre-service teachers. Pre-test and post-test data were collected using the conceptual physics problems test (CPPT), and written responses to blended conceptual problems were graded using a moderated memorandum and analysed quantitatively. The results provide evidence of the effectiveness of the SPSE blended model. In particular, performance on tasks categorised as D2 and D3 improved significantly among pre-service teachers who followed the SPSE blended model compared to those who followed the lecture-based approach. However, I found no significant differences in performance on tasks designated as D1 between the two groups. This suggests that while the blended model enhances learning for solving certain types of conceptual problems, it may not universally apply to all types of tasks. Further investigation may be necessary to understand the nuances of how different learning models impact the blending of conceptual physics problems into solution frameworks among pre-service teacher
Special issue: CSTL in Sub-Saharan Africa
No full textThis special issue is overdue, given the adoption of the CSTL framework (CSTL Regional Steering Committee 2015) in the SADC region since 2008. Many questions have been asked about the extent to which the CSTL framework has been successful in engendering a strong system of care and support for learners in schools. We begin by providing an oversight of CSTL, when and why it was adopted in the Southern African Development Community (SADC) region and what it hopes to achieve in the development of inclusive schools. We then provide an overview of the 6 articles included in this special issue. The care and support for Teaching and Learning (CSTL) framework emerged as a response to the complex barriers preventing vulnerable children in South Africa from accessing quality education which is a crucial to SDG 4. Despite several policy reforms since post- 1994, vulnerable children across the country face challenges in accessing, completing and succeeding in education. In 2008, the CSTL framework was formally adopted by 14 Southern African Development Community (SADC) member states and subsequently launched in 2010 at the SADC Education ministers’ meeting. CSTL was developed to provide a comprehensive, overarching structure to coordinate implementation efforts, enabling the delivery of integrated care and support in schools under the leadership of the Department of Basic Education. The main aim of the CSTL framework is to create schools that function as inclusive centres of care, learning and support. The intention is to strengthen protective factors in schools to promote children’s well-being and reduce risk factors. CSTL aims to create, amongst others, schools that build on the strengths of learners and educators and have appropriate infrastructure with good water and sanitation. It also aims to create safe, supportive schools, primarily through a range of services that are discrimination-free, involve parents and caregivers, and work through partnerships with multiple stakeholders
Technical considerations for use of sodium azide in plant biotechnology-assisted genetic improvement
No full textodium azide has been used in plant biotechnology as a mutagen to induce genetic variation in plants for the purpose of improving traits such as yield, disease resistance, and stress tolerance, for more than four decades. It acts by causing random mutations and researchers can expose plant seeds and a variety of zygotic and vegetative explants to sodium azide for this purpose. Sodium azide can also be used in combination with other biotechnological tools, such as genetic engineering, to further enhance the genetic improvement of plants; for example, to induce mutations in plants that have been genetically modified to overexpress certain genes. Its sustained use over what has been plant biotechnology’s most intense period of innovation speaks to the value of sodium azide as a tool for creating genetic diversity and facilitating the development of new plant varieties with improved traits. Its widespread application in plant biotechnology has led to a lot of variation across facilities/laboratories and species in terms of the methods of exposure, tissues targeted, concentrations used, mutagenic efficiency and biological consequences. The use of mutagens like sodium azide also raises ethical concerns around the unintended consequences and potential risks of mutagens to the environment and human health. This motivated the current review on the technical considerations for the use of sodium azide in plant biotechnology-assisted genetic improvement. Despite the challenges associated with the use of sodium azide (mainly related to a decline in growth) when the method of application is optimized (in terms of plant material, concentration and exposure method) the technique can be a valuable, low cost, option for developing new plant varieties with improved characteristics that can benefit agriculture and food security. © Plant Science and Biodiversity Centre, Slovak Academy of Sciences (SAS), Institute of Zoology, Slovak Academy of Sciences (SAS), Institute of Molecular Biology, Slovak Academy of Sciences (SAS
Violating Nigerian medical doctorcontract: Do I remain committed to my employer and nation?
No full textOrientation: In recent years, the healthcare sector in Nigeria has faced significant challenges, including high turnover rates among medical professionals. Previous studies have only focused on monetary reasons for turnover, but there is a gap in understanding how psychological factors predict turnover.Research purpose: This study examined how psychological contract violation affects the intention to remain or leave among medical doctors in Nigeria. Motivation for the study: Having an understanding of how medical doctors navigate the breach of their contract and their commitment is important for improving retention strategies and subsequent overall healthcare system in Nigeria. Research approach/design and method: A cross-sectional survey research design was adopted and quantitative data were gathered from 362 medical doctors. More of the respondents (69.6%) were doing their residency. Main findings: Findings revealed that employee retention had a significant relationship with perceived breach and feelings of violation (p < 0.01). The dimensions of psychological contract violation accounted for about 53% variance in employee retention [R2=0.53; F (2, 359)=201.01; p < 0.01]; also, perceived breach and feelings of violation were significant independent predictors of employee retention. Practical/managerial implications: The study recommends that the Ministry of Health in Nigeria consider reviewing the bond and terms of the working relationship between medical doctors and employers to reduce the brain drain of medical doctors. Contribution/value-add: The study helps to connect psychological and organisational factors in the turnover rate of medical doctors, unraveling that non-monetary factors also play a crucial role
Impacts and statistical mitigation of missing data on the 21 cm power spectrum: a case study with the hydrogen epoch of reionization array
No full textThe precise characterization and mitigation of systematic effects is one of the biggest roadblocks impeding the detection of the fluctuations of cosmological 21 cm signals. Missing data in radio cosmological experiments, often due to radio frequency interference (RFI), pose a particular challenge to power spectrum analysis as this could lead to the ringing of bright foreground modes in the Fourier space, heavily contaminating the cosmological signals. Here we show that the problem of missing data becomes even more arduous in the presence of systematic effects. Using a realistic numerical simulation, we demonstrate that partially flagged data combined with systematic effects can introduce significant foreground ringing. We show that such an effect can be mitigated through inpainting the missing data. We present a rigorous statistical framework that incorporates the process of inpainting missing data into a quadratic estimator of the 21 cm power spectrum. Under this framework, the uncertainties associated with our inpainting method and its impact on power spectrum statistics can be understood. These results are applied to the latest Phase II observations taken by the Hydrogen Epoch of Reionization Array, forming a crucial component in power spectrum analyses as we move toward detecting 21 cm signals in the ever more noisy RFI environment
On automorphism groups of the conjugacy class type Cayley graphs on the symmetric and alternating groups
No full textThe automorphism groups of Cayley graphs on symmetric groups, Cay(G, S), where S is a complete set of transpositions have been determined. In a similar spirit, automorphism groups of Cayley graphs Cay(An, S) on alternating groups An, where S is a set of all 3-cycles have also been determined. It has, in addition, been shown that these graphs are not normal. In all these Cayley graphs, one observes that their corresponding Cayley sets are a union of conjugacy classes. In this paper, we determine in their generality, the automorphism groups of Cay(G, S), where G ∈ {An, Sn} and S is a conjugacy class type Cayley set. Further, we show that the family of these graphs form a Boolean algebra. It is first shown that Aut(Cay(G, S)), S ∉ {∅, G \ {e}}, is primitive if and only if G = An. Using one of the results obtained by Praeger in 1990, we exploit further the other cases, thereby proving that, for n > 4 and n ≠ 6, Aut(Cay(An, S)) ≅ Hol(An ) ⋊ 2, with Hol(G) ∼= G ⋊ Aut(G), provided that S is preserved by the outer automorphism defined by the conjugation by an odd permutation. Finally, in the remaining case G = Sn, n > 4 and n ≠ 6, we show that Aut(Cay(Sn, S) ≅ (Hol(An) ⋊ 2) ≀ S2 for S ⊂ An \ {e}, and that Aut(Cay(Sn , S)) ≅ Hol(Sn) ⋊ 2 otherwise; provided that S does not contain Sn \ An or S ≠ An \ {e}, S ∉ {∅, Sn \ {e}}
Smart worksheets and their positive impact on a first-year quantitative chemistry course
No full textThe pandemic was a very difficult time for everyone, as well as teachers and their students. Teachers of first-year quantitative chemistry courses, both during the pandemic and postpandemic, encountered many pandemic-induced difficulties, including inter alia communicating with individual students, providing them with rapid formative feedback, and determining where they were on their learning journey. In addition, two cohorts of students requiring different teaching approaches were enrolled on this course during the period of this study (2020-2023). One cohort had a post-16 mathematics qualification (A-level that includes calculus) and the other, a pre-16 mathematics qualification (GCSE that does not include calculus) as their highest mathematics qualification. In this Article, we show the value of using Smart Worksheets to address these challenges. The Smart Worksheets provided valuable information about the students’ ability to apply mathematical concepts within a chemistry context and, consequently, allowed the teaching team to shape workshops to cater for any application difficulties. Smart Worksheets clearly identified a number of (basic) skills that many of the students were struggling with, including graphing, uncertainty analysis, application of units, and application of logs to buffer calculations. Smart Worksheets also allowed the teaching team to connect with students, to either commend them on their work or ask how they were coping if they appeared to be struggling. Students highlighted how the instant formative feedback provided by Smart Worksheets and their unlimited availability during the course impacted positively on their learning. The Smart Worksheets also helped to identify two subgroups in the student cohort with the higher mathematics qualification; one subgroup could apply their mathematics knowledge within different chemistry contexts while the other subgroup was not able to move from a mathematical context to a chemistry context. This information allowed the teaching team to alter workshop approaches to emphasize translation from one context to another
Temporal shifts in key mangrove crab species linked to biotic and abiotic factors at a latitudinal range limit
No full textMangroves in South Africa occur at a southern latitudinal limit (33°12′51″ S, 27°34′54″ E) where distribution is influenced by global climate change. Mangroves are experiencing poleward expansion, affecting the distribution of associated macrofauna. Monitoring surveys have been conducted for South African mangrove macrofauna, with research focusing on drivers of ocypodid crabs rather than grapsoid crabs, despite the key role of grapsoids in this ecosystem. Using uni- and multivariate models, we investigated (i) changes in brachyuran community over time (2016 vs 2023), (ii) the potential biotic (food availability, brachyuran diversity and abundance) and abiotic (sediment, water and geographic parameters) factors influencing occurrence and abundance of three co-occurring mangrove crabs (Austruca occidentalis, Neosarmatium africanum and Cristarma eulimene) along the east coast of South Africa, and (iii) the potential distribution of these three species under climate change scenarios. Brachyuran community structure changed significantly over time (2016–2023) at all mangrove sites sampled (df = 1, pseudo-f = 13.95, p < 0.05). Overall, the presence and abundance of all three species were influenced by total brachyuran abundance and diversity, with latitude also influencing the occurrence of these crabs. Specifically, A. occidentalis occurrence was correlated with sediment organic matter and importance values of mangrove tree species to forest structure, while temperature, salinity and sediment moisture influenced their abundance. The presence and abundance of both sesarmids were driven by microphytobenthos and salinity, while temperature influenced abundance. Both climate change scenarios (SSP245 and SSP585) projected future shifts in distribution of all three crab species, with warmer temperatures and increased rainfall patterns expanding habitat suitability of sesarmids in a poleward direction while contracting fiddler crab ranges. This study highlights the ongoing and future impacts of climate change in South African mangroves and their associated macrofauna, suggesting a projected poleward expansion in response to climate change. Additionally, this study highlights future distributional shifts of mangrove associated crabs that can likely alter coastal ecosystem dynamics
Doping of iron transition metal onto cerium oxide lattice for enhanced photocatalytic degradation of acid violet 7 azo dye under solar irradiation
No full textDye-contaminated water possess a severe environmental problem due to its adverse effects on ecosystems, human health, and water resources. In this study, cerium oxide (CeO2) was successfully produced and doped with different ratios of iron (5,10 and 15 mol%) via a facile co-precipitation method for use in photocatalytic degradation of acid violet 7 (AV7) from an aqueous solution. The physicochemical properties of the nanophotocatalysts were studied using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Ultraviolet–Visible spectrophotometer (UV–Vis), Raman spectroscopy, photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), and Brunauer-Emmett-Teller (BET). SEM-EDS confirmed the presence of Fe, O and Ce elements in the photocatalysts. The 5 mol% Fe-dopped CeO2 possess high photocatalytic activity with the removal efficiency of approximately 98 % of AV7 dye when compared to pristine CeO2 (38 %), 10 % Fe-doped CeO2 (85 %) and 15 % Fe-doped (86 %). The higher photodegradation of 5 mol% Fe-doped CeO2 was attributed to suppressed recombination of photogenerated charge carriers as displayed by PL, as well as the high surface area observed from BET analysis. In addition, the electrochemical characterization confirmed high migration of photogenerated electron-hole pairs for 5 mol% Fe-CeO2/FTO which substantiates the enhanced photocatalytic degradation of AV7