Walter Sisulu University
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Sol-gel produced Zn2V2O7 phosphors’ improved luminous properties: The role of thermal treatment
Get PDFZn2V2O7 phosphor was made using a sol-gel technique and then annealed at temperatures ranging from 700 to 850 ◦C. The x-ray diffraction (XRD) results revealed that Zn2V2O7 exhibits a single monoclinic phase. The width at half-maximum of the (022) XRD peak shrank overall resulting in improved crystallinity of the Zn2V2O7 phosphors with higher annealing temperatures. Because of the good crystallinity of Zn2V2O7, scanning electron microscopy (SEM) indicates that grain size increases as the annealing temperature rises. When the temperature was raised from 35 ◦C to 500 ◦C, TGA findings revealed a total weight loss of approximately 65%. The photoluminescence emission spectra of annealed Zn2V2O7 powders revealed a wide green-yellowish emission in the range of 400 nm–800 nm. As the annealing temperature was raised, the crystallinity improved, resulting in an increase in PL intensity. The peak of the PL emission shifts from green to yellow emission
Efffectiveness of using the strategy instructions approach (SIA) in teaching reading comprehension: A stud of selected schools in the Amathole East District
No full textThis study sought to explore the effectiveness of using the strategy instructions approach (SIA) to teaching reading comprehension. This research was necessitated by the fact that most South African children do not perform well when it comes to reading comprehension. Many researchers from the literature, such as Rule (2017) and Pretorius and Klapwijk (2016), revealed that most language teachers, especially English First Additional Language teachers, do not have adequate skills to teach learners reading comprehension effectively. Even though in the Curriculum and Assessment Policy Statement (CAPS) document, which should serve as the ultimate guide for teaching English, some strategies are clearly spelt out to be used to teach reading comprehension, the teachers do not use them. This study used the SIA, which contains some of those strategies in the CAPS documents to teach the reading comprehension to grade 8 learners in Elliotdale CMC in the Amathole East District of the Eastern Cape of the Republic of South Africa. The study also sought to find out if SIA could develop positive attitudes and autonomy in the learners towards reading comprehension. The constructivist theory of learning and the schema theory of teaching reading comprehension were the two theories that underpinned the study. A control group and an experimental group (sampled from three schools) were used to determine the effectiveness of SIA when compared to the traditional teaching approaches used by teachers to teach reading comprehension. The study revealed that the use of SIA to teach reading comprehension developed positive attitudes and autonomy in reading comprehension. Finally, SIA has become effective to increase the performance of learners in reading comprehension. The study recommends that teachers should be trained in the higher institutions to use SIA to teach reading comprehension and teachers in the field should be developed to learn how to use the strategies to teach reading comprehension. In addition, more hours should be allocated on the school timetables for teaching reading comprehension. Finally, more reading materials, together with more reading activities, should be given to learners in the schools, especially schools in the rural areas.Thesis (Masters) -- Faculty of Education, 202
Acaricide Resistance Development in Rhipicephalus (Boophilus) Microplus (Acari: Ixodidae) Populations against Amitraz and Deltamethrin on Communal Farms of the King Sabata Dalindyebo Municipality, South Africa
Get PDFChemical acaricides are widely used to control ticks and tick-borne pathogens in cattle. However, prolonged and indiscriminate use of these chemicals inevitably leads to the selection ofresistant ticks. In-vitro bioassays (adult and larval immersion tests) were conducted to assess amitrazand deltamethrin resistance inRhipicephalus (Boophilus) micropluspopulations from communal farms of the King Sabata Dalindyebo municipality of South Africa. Data generated on percentage inhibitionof oviposition revealed that all the tick populations assessed showed resistance to at least one of the acaricides. All six tick populations assessed for efficacy at the DD)with deltamethrin were resistant and only one of the six tick populations assessed forefficacy with amitraz was susceptible. Based on the resistance ratios (RR), the adult immersion testdetected amitraz and deltamethrin resistance in three (RR ranging from 2.30 to 3.21) and five (RRranging from 4.10 to 14.59) of the six tick populations, respectively. With the larval immersion test,deltamethrin and amitraz resistance (larval mortality 90% at the DD) was detected in all four andthree of fourR. (B.) micropluspopulations assessed, respectively. These data are critical for the designof an effective and sustainable tick control strategy on the communal farms
Discontinuities in Earnings Distributions: Evidence from South Africa
Get PDFThere is increasing evidence that earnings management amongst firms creates discontinuity in the earnings distribution. We have verified the evidence of discontinuity in earnings distribution for 246 Johannesburg Securities Exchange-listed firms from 2003 to 2018. The assets-scaled income was used as earnings measure to present the empirical histograms; the standardized difference test of significance was utilized to establish the existence of discontinuities at zero. The result shows discontinuities in distributions for earnings level and earnings change. In addition, except for the unscaled earnings, the evidence supposes that the sample design does not explain the discontinuity in the earnings (earnings change) distributions
A Bibliometric Analysis on Spectrum Sensing in Wireless Networks
Get PDFSpectrum scarcity is a prevalent problem in wireless networks due to network regulatory bodies' strict allotment of the spectrum (frequency bands) to licensed users. Such an operation implies that the unlicensed users (secondary wireless spectrum users) have to evacuate the spectrum when the primary wireless spectrum users (licensed users) are utilising the frequency bands to avoid interference. Cognitive radio alleviates the spectrum shortage by detecting unoccupied frequency bands. This reduces the underutilization of frequency bands in wireless networks. There have been numerous related studies on spectrum sensing; however, few studies have conducted a bibliometric analysis on this subject. This study’s goal was to conduct a bibliometric analysis on the optimisation of spectrum sensing. The PRISMA methodology was the basis for the bibliometric analysis to identify the limitations of the existing spectrum-sensing techniques. The findings revealed that various machine-learning or hybrid models outperformed the traditional techniques, such as matched filter and energy detectors, at the lowest signal-to-noise ratio (SNR). SNR is the ratio of the desired signal’s magnitude to the background noise magnitude. This study, therefore, recommends that researchers propose alternative techniques to optimise (improve) spectrum sensing in wireless networks. More work should be done to develop models that optimise spectrum sensing at low SNR
Unveiling the Green Impact: Exporing the Nexus Between Trade Openness and Enviromental Quality in South Africa
Get PDFIn light of the escalating concerns about environmental sustainability and the profound impact of international trade on environmental outcomes, the study's focal point was to empirically investigate the relationship between trade openness and environmental quality in South Africa from 1994 to 2018. In order to achieve the goal, the research utilised the Autoregressive Distributed Lag (ARDL) Bounds method and the Granger causality test for analysing data. The ARDL Bounds approach was chosen for its ability to examine both short-run and long-run relationships, while the Granger causality test provided insights into the direction of causality between the variables. This combination of robust econometric techniques enhances the reliability and depth of the study's findings, leading to a more comprehensive understanding of the complex relationship between trade openness and environmental quality in the country. The analysis results revealed a significant and positive relationship between trade openness and carbon emissions in the short and long run. The Granger causality test also indicated a unidirectional causality from trade openness to environmental quality. These implications are paramount for the South African government's policy formulation. In order to tackle the environmental issues that come with open trade, the government must put in place trade agreements that will enhance its ability to address these concerns efficiently. One crucial step is reducing trade barriers on environmental goods, facilitating increased access to green technologies at lower costs. Moreover, the government should prioritise enacting and enforcing strict environmental laws to avoid the "pollution haven hypothesis," which often affects low-income countries
Steroids and Fatty Acid Esters from Cyperus Sexangularis Leaf and Their Antioxidant, Anti-Inflammatory and Anti-Elastase Properties
Get PDFCyperus sexangularis(CS) is a plant in the sedge family (Cyperaceae) that grows abundantly in swampy areas. The leaf sheaths of plants in the Cyperus genus are mostly used domestically for mat making, while they are implicated for skin treatment in traditional medicine. The plant was investigated for its phytochemical contents as well as its antioxidant, anti-inflammatory and anti-elastase properties. The n-hexane and dichloromethane leaf extracts were chromatographed on a silica gel column to afford compounds 1–6. The compounds were characterised by nuclear magnetic resonance spectroscopy and mass spectrometry. The inhibitory effect of each compound against 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and ferric ion radicals was determined by standard in vitro antioxidant methods. The in vitro anti-inflammatory response was measured using the egg albumin denaturation (EAD) assay, while the anti-elastase activity of each compound in human keratinocyte (HaCaT) cells was also monitored. The compounds were characterised as three steroidal derivatives, stigmasterol (1), 17-(1-methyl-allyl)-hexadecahydro-cyclopenta[a]phenanthrene (2), sitosterol (3), dodecanoic acid (4) and two fatty acid esters, ethyl nonadecanoate (5) and ethylstearate (6). Stigmasterol (1) exhibited the best biological properties, with an IC50of 38.182.30g/mL against DPPH, 68.564.03g/mL against NO and 303.5810.33AAE/mg against Fe3+. At 6.25 g/mL, stigmasterol inhibited EAD by 50%. This activity was lower when compared to diclofenac (standard), which demonstrated 75% inhibition of the protein at the same concentration. Compounds 1, 3, 4, and 5 showed comparable anti-elastase activity with an IC50 of 50 g/mL, whereas the activity of ursolic acid (standard) was twofold with an IC50of 24.802.60g/mL when compared to each of the compounds. In conclusion, this study has identified three steroids(1–3), one fatty acid (4), and two fatty acid esters (5and6) in C. sexangularis leaf for the first time. The compounds showed considerable antioxidant, anti-inflammatory and anti-elastase properties. Thus, the findings may serve as a justification for the folkloric use of the plant as a local skin ingredient. It may also serve to validate the biological role of steroids and fatty acid compounds in cosmeceutical formulations
Fostering University Students’ Motivation through Dialogic Classroom Practices: A Conceptual Model
Get PDFThis conceptual paper presents a model for engaging students and promoting motivation through dialogic classroom practices. The author argues that fostering dialogic teaching and learning in the classroom can positively impact student motivation and learning outcomes. The proposed model highlights the importance of creating a classroom environment where students feel comfortable sharing their ideas and engaging in meaningful discussions. This conceptual article is lensed within transformative paradigm, presenting dialogic pedagogy as a concept analysed using conceptual analysis. Dialogic pedagogy was presented, and the key assumptions, such as promoting classroom dialogue, valuing all voices, emphasising social knowledge construction, and instructors acting as facilitators of learning, were discussed vis-à-vis its correctional tendencies with student motivation and learning outcomes. The paper also highlights the potential benefits of dialogic classroom practices for diverse and borderless student populations. The conclusion is that promoting classroom dialogue, valuing all voices, emphasising social knowledge construction, and acting as facilitators of learning are dimensions to enhance student motivation towards learning outcomes. The paper offers a valuable contribution to the literature by providing a comprehensive framework for educators to effectively engage and motivate their students through dialogic practices
One World, One Health: A Growing Need for an Intergrated Global Health Approach
Get PDFThe increasing pressures on the human–animal–plant–environment interface contribute to the development of new and more complex diseases.1 In many cases, infectious disease outbreaks have strong links with environmental changes, such as the loss of biodiversity, the degradation of ecosystems and climate hazards,2caused by anthropogenic activities. There is an urgent need to move from a global health perspective to an integrated ‘One Health’ approach. The coronavirus disease 2019 (COVID-19) pandemic has shown that the degradation of the environment is contributing to the increasing health risks faced by society. The emergence of the coronavirus in humans has highlighted the need for more effective and multi-disciplinary coordinated efforts.1,3Furthermore, our collective responsibility is to prevent, predict, detect and respond to global health threats. Our current understanding of the various interactions between humans, animals, plants and the environment must be re-evaluated
Acute Kidney Injury Among Hospitalised Patients Who Died Due to Covid-19 in the Eastern Cape South Africa
Get PDFAcute kidney injury (AKI) commonly occurs in coronavirus disease 2019 (COVID-19) patients who have been hospitalised and is associated with a poor prognosis. This study aimed to determine the incidence of AKI among COVID-19 patients who died in a regional hospital in South Africa..