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Effect of fire severity on Afrotemperate forest tree survival
Get PDFWeather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broad-leaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change.Thesis (MSc) -- Faculty of Science, 202
Design and fabrication of electrochemical sensor based on molecularly imprinted polymer loaded onto silver nanoparticles for the detection of 17-β-Estradiol
Get PDFIn this research report, we prepared an electrochemical sensor based on the molecularly imprinted poly(p-aminophenol) supported by silver nanoparticles capped with 2-mercaptobenzoxazole for the selective and sensitive detection of endocrine disrupting 17-β-estradiol (E2). The electropolymerization of the functional monomer prepared the proposed molecularly imprinted polymer (MIP) composite-based sensor in the presence of E2 as a template. The recognition materials were characterized using Fourier transform infrared, cyclic voltammetry (CV), square wave voltammetry (SWV), scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray powder diffraction techniques. The electrochemical measurements were performed by employing both CV and SWV methods. We did the optimization of critical parameters affecting the sensor performances through the experimental design and verification. The developed sensor showed a linear range from 10 pM to 100 nM with the calculated quantification and detection limits of 1.86 and 6.19 pM, respectively. The incorporation of AgNP with high electrical conductivity into the MIP matrix enhanced the sensor's performance. Furthermore, the sensor was applied to determine E2 in real water samples without any sample preconcentration steps to achieve the percent recovery of 91.87% to 98.36% and acceptable reusability and storage stability performances
The Women’s Development Foundation Award to Dr. Jean Swanson-Jacobus
No full textThe Women's Development Award to Jean Swanson-Jacobus (Dr.), "honoring your contribution to the first Democratic National Assembly of the Republic of South Africa 1994-1999".Donated/gifted to Nelson Mandela University ArchivesForms part of: Brigalia Bam collectio
Small African clay pot, rust color with silver alloy patterns
No full textSmall African clay pot, rust color with silver alloy patterns.Women have acquired amazing skills in making mats, pots, baskets, e.c.t. to preserve African Art.Donated/gifted to Nelson Mandela University ArchivesForms part of: Brigalia Bam collectio
Clinicians knowledge and perceptions of point of care testing (poct) in selected hospitals in the free state, South Africa
Get PDFPoint of care testing (POCT) improves access and equity to health diagnostic services in resource-limited settings like South Africa, where some health facilities do not have on-site laboratories. With recent technological advancements, most traditional laboratory tests can now be conducted on-site at primary health clinics (PHC), hospital wards and clinics. One advantage of the POCT device is that it can be used by a non-medical laboratory expert at the patient’s bed side during hospitalizations or near the patient in the doctor’s consultation rooms. This results in a shorter turnaround time for the availability of test results when compared to that from a specimen sent to a traditional clinical laboratory. Despite the benefits of POCT, many clinicians (doctors and nurses) avoid utilizing POCT for quality assurance reasons. Clinicians believe the results from a POCT device may not be as reliable as the results from tests performed by a medical laboratory scientist in the traditional clinical laboratory. This study used a concurrent mixed method research design to explore clinicians' POCT knowledge and attitudes in a subset of hospitals in the Free state of South Africa. The study population comprised of consenting medical professionals from the ten (10) selected Free State district hospitals (study sites). The findings demonstrated that hospitals in urban areas have easier access to laboratory services. There were two (2) urban study sites that had on-site laboratories which achieved faster Turn-Around-Time (TAT). The participants indicate that they are aware of POCT and routinely use it, but there are far fewer POCT tests available than laboratory tests. When diagnostic options are scarce, point-of-care testing (POCT) can provide a more accurate diagnosis than traditional methods. The improved health care provision and reduced incidence of health complications is the end result. According to the participants, having access to POCT diagnostic services has shown promise in addressing challenges that sometimes present with laboratory-based methods, particularly in settings with limited access to hospitals or when laboratories cannot be accessed. Further, clinicians argue that errors in the usage of POCT may occur due to the quality of these POCTs and improper documentation of the test results by the clinicians. Therefore, poor utilization of POCT by clinicians can be improved if implemented with pre-set strict selection goals and processes to ensure that the right POCT is selected for the right purpose that would reduce resource expenditure by the hospitals and improve patient experiences and health outcomes.Thesis (MPH) -- Faculty of Health Sciences, 202
The utilization of contraceptives amongst adolescents at Stutterheim in the Eastern Cape Province
Get PDFIntroduction Contraception has been identified as one way in which women can prevent unwanted pregnancies. Contraceptive utilization has been proved to minimize maternal mortality by lowering the risk of pregnancy and its associated life-threatening problems. Therefore, the researcher conducted a study at Stutterheim about the “utilization of contraceptives amongst adolescents at Stutterheim in Eastern Cape Province” with the intentions to explore perceptions of adolescents on utilization of contraceptives and to determine the factors that influence that contraceptive utilization. Methods This study adopted a quantitative, descriptive cross-sectional design which involved questionnaire tools completed by 436 adolescents between the ages of 14 and 19 years at Stutterheim health facilities and the surrounding schools, regardless of whether they were sexually active or not. After obtaining ethical clearance from the University ethics Committee and permission from the Department of Health the researcher visited the gatekeepers for obtaining informed consent and data collection procedures. The researcher administered the instruments herself to ensure validity and reliability of the instrument through a pilot study. The respondents of the pilot study did not participate in the major study. Any irregularities with the data instruments were corrected accordingly. Data collection took 3 weeks to complete all the sites. The raw data was captured onto an Excel spread sheet and analysed by the researcher with the assistance of a statistician. Results The data suggests that as much as the parents discuss about sex related issues and pregnancy, they are less likely to educate their adolescent girls about contraceptives probably due to the beliefs they have, lack of knowledge and the fear of introducing them into premarital sex. The 34.4percent of participants indicated that they were scared of contraceptive rumours spreading around the community as well as the stigmatization. Conclusion Due to the results of this study the Department of Health should work together with the department of education to put into effect the optimal utilization of contraceptives amongst adolescents by adding sexual, reproductive and contraceptives health education, as a subject in the school curriculum. Department of health must also make use of main media and social media since they are influential and can be the great sources of information for campaigns and more seminars on contraceptive utilization and its benefits to the adolescents, society and the State.Thesis (MPH) -- Faculty of Health Science, 202
Simplified menu-driven data analysis tool with macro-like automation
Get PDFThis study seeks to improve the data analysis process for individuals and small businesses with limited resources by developing a simplified data analysis software tool that allows users to carry out data analysis effectively and efficiently. Design considerations were identified to address limitations common in such environments, these included making the tool easy-to-use, requiring only a basic understanding of the data analysis process, designing the tool in manner that minimises computing resource requirements and user interaction and implementing it using Python which is open-source, effective and efficient in processing data. We develop a prototype simplified data analysis tool as a proof-of-concept. The tool has two components, namely, core elements which provide functionality for the data anal- ysis process including data collection, transformations, analysis and visualizations, and automation and performance enhancements to improve the data analysis process. The automation enhancements consist of the record and playback macro feature while the performance enhancements include multiprocessing and multi-threading abilities. The data analysis software was developed to analyse various alpha-numeric data formats by using a variety of statistical and mathematical techniques. The record and playback macro feature enhances the data analysis process by saving users time and computing resources when analysing large volumes of data or carrying out repetitive data analysis tasks. The feature has two components namely, the record component that is used to record data analysis steps and the playback component used to execute recorded steps. The simplified data analysis tool has parallelization designed and implemented which allows users to carry out two or more analysis tasks at a time, this improves productivity as users can do other tasks while the tool is processing data using recorded steps in the background. The tool was created and subsequently tested using common analysis scenarios applied to network data, log data and stock data. Results show that decision-making requirements such as accurate information, can be satisfied using this analysis tool. Based on the functionality implemented, similar analysis functionality to that provided by Microsoft Excel is available, but in a simplified manner. Moreover, a more sophisticated macro functionality is provided for the execution of repetitive tasks using the recording feature. Overall, the study found that the simplified data analysis tool is functional, usable, scalable, efficient and can carry out multiple analysis tasks simultaneously.Thesis (MSc) -- Faculty of Science, Computer Science, 202
Long-term trends in fish length-at-age, catch-at-length and condition of the Namibian and South African commercially exploited species
Get PDFFish growth rate is a flexible trait that can evolve in response to fishing or environmental change. Therefore, knowledge of fish growth rate patterns, long-term and short-term responses to fishing effort and environmental change is important for fisheries management in the Benguela. Historical and current age length keys have been used as indicators of annual fish growth in the Benguela, the growth rate study on Merluccius paradoxus demonstrated long-term changes in growth over three decades as a response to fishing. However, the fish growth rate patterns, in relation to fishing effort and environmental change patterns are still not known for the many commercially important stocks in the Benguela. The specific objectives of the project were to determine the annual variability and long-term trends, in annual mean lengths-at-age, catch-at-length and fish condition of 17 commercially exploited resources, targeted and bycatch in Namibia and South Africa in relation to environmental changes (sea surface temperature). The results showed that there was a significant decrease in mean length at age 7 for Merluccius capensis (Namibian stock), a significant decrease in mean length at ages 3 to 7 for South African M. capensis and a significant increase in mean length at ages 2 to 6 for South African M. paradoxus Fishery-induced evolution may be the reason for the increase in mean length in the early stages of hake. A regime shift was detected in the mean length at age 1 for Etrumeus whiteheadi (South African stock) caused by changes in water temperatures. A decrease in mean length of the catch was observed for Namibian M. capensis and the reason for this could have been the stock being overexploited during the years of the observed trend (1968 to 1987). Historically both the Namibian Lophius vomerinus and Helicolenus dactylopterus were bycatch of the hake fishery, therefore, the decrease in their mean length of the catch may be due to increased bycatch mortalities due to increased hake catches. The improvement in the management measures of the Jasus lalandii fishery and possible favourable oxygen fluctuation might have caused the stock to increase in mean length of the catch between 1977 and 1982. Fish condition showed a significant difference in stocks between years. Fish condition of M. capensis, M. paradoxus and T. capensis were analysed. The rest of the commercial stocks were omitted because there was limited length-weight data. For Namibian M. capensis the spawning season may have caused fish to have the best condition in 1987 and while higher temperatures in 1983 may have led to the worst condition in 1983. Higher prey availability in 1979 for Namibian M. paradoxus could have been the reason for fish with best condition being found in 1979. T. capensis had the highest condition index in 1986 when cooler summer SST prevailed that may have been more favourable for T. capensis to live in. July, September and January SSTs were significantly negatively correlated with the mean length of M. capensis at age 3. This was perhaps due to upwelling intensity and plankton productivity which increases in winter and decreases in summer. A separate study of the impacts of fishery-induced changes and density-dependence on fish growth rate, as well as the effects of other environmental variables is recommended. Since data for some species was outdated, it is suggested to update biological variables and assessment for future work. This study can be used to understand the key life history characteristics of Namibian and South African exploited resources, targeted and bycatch.Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 202
Mechanistic analysis of two cytotoxic thiazolidinones as novel inhibitors of Triple-Negative Breast Cancer
Get PDFThesis embargoes. Expected release date early 2025.Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 202
The meanings of the social media practices of African women engaged in multi-level marketing in Makhanda
Get PDFIn their efforts for a place in the economy, many South African women have embraced opportunities in the informal sector such as selling products for big Multi-Level Marketers (MLMs), who generally operate on a pyramid structure of commissions. This qualitative study investigates the meanings African women engaged in MLMs in Makhanda make of such work and examines how they construct notions of progress and success through their social media practices. The study was conducted in the strictest lockdown period and pioneered a research method that used Zoom to facilitate screen sharing on mobile phones to create an online version of the scroll-back method for Facebook. As expected for women working in a society increasingly integrated in a global neoliberal order, many of the meanings the women construct are rooted in neoliberal discourses that celebrate hyper-individualism and competition. This firstly includes constructing success through personal stories of self-appreciation, through which these women embody the MLM’s brand, while simultaneously improving their position in the market as sellers. Secondly, the women invest considerable effort on social media in constructing MLM work as epitomising stability in the context of the growing precarity that characterises their everyday lives. However, other meanings draw on the local African context. Here the women make sense of the inequalities that characterise the MLM pyramid structures, by constructing top players in the upline as a symbolic vanguard trailblazing freedom from a racist past through showcasing paths out of poverty. More interestingly, success is constructed as both resulting from and serving collective ways of being rooted in the discourse of African humanism. Here success is recognised as emerging from dense place-based networks in the neighbourhood built on trust and obligation, now replicated on social media. In conclusion, the study speculates that the worlds of meaning facilitated by MLMs might provide ways for neoliberal and traditional discourses to find points of synergy, and so serve as entry points into a neoliberal order that interestingly nevertheless draws on communal cultures of obligation and patronage.Thesis (MA) -- Faculty of Humanities, School of Journalism and Media Studies, 202