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A multispectral and machine learning approach to early stress classification in plants

- Poole, Louise Carmen

Authors: Poole, Louise Carmen
Date: 2022-04-06
Subjects: Machine learning , Neural networks (Computer science) , Multispectral imaging , Image processing , Plant stress detection‎
Language: English
Type: Master's thesis , text
Identifier: http://hdl.handle.net/10962/232410 , vital:49989
Description: Crop loss and failure can impact both a country’s economy and food security, often to devastating effects. As such, the importance of successfully detecting plant stresses early in their development is essential to minimize spread and damage to crop production. Identification of the stress and the stress-causing agent is the most critical and challenging step in plant and crop protection. With the development of and increase in ease of access to new equipment and technology in recent years, the use of spectroscopy in the early detection of plant diseases has become notably popular. This thesis narrows down the most suitable multispectral imaging techniques and machine learning algorithms for early stress detection. Datasets were collected of visible images and multispectral images. Dehydration was selected as the plant stress type for the main experiments, and data was collected from six plant species typically used in agriculture. Key contributions of this thesis include multispectral and visible datasets showing plant dehydration as well as a separate preliminary dataset on plant disease. Promising results on dehydration showed statistically significant accuracy improvements in the multispectral imaging compared to visible imaging for early stress detection, with multispectral input obtaining a 92.50% accuracy over visible input’s 77.50% on general plant species. The system was effective at stress detection on known plant species, with multispectral imaging introducing greater improvement to early stress detection than advanced stress detection. Furthermore, strong species discrimination was achieved when exclusively testing either early or advanced dehydration against healthy species. , Thesis (MSc) -- Faculty of Science, Ichthyology & Fisheries Sciences, 2022
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Date Issued: 2022-04-06

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A retrospective study of antimicrobial prescribing practices in paediatric patients at the Mahalapye District Hospital, Central Botswana

- Nyawera, Angella

Authors: Nyawera, Angella
Date: 2022-04-06
Subjects: Uncatalogued
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/290682 , vital:56774
Description: Background: The development of antimicrobial resistance (AMR) has been linked to the increased and irrational use of antimicrobial medicines. The aim of this study was to investigate the antimicrobial prescribing practices in the paediatric medical ward at Mahalapye District Hospital (MDH) in Botswana and to determine whether antimicrobial stewardship (AMS) measures were being implemented at the hospital. Methods A cross-sectional, descriptive, mixed methods, observational approach was taken in this study. The study site was the paediatric medical ward (PMW) at MDH. Information about the antimicrobials prescribed for paediatric patients from January 2018 to December 2018 was collected from patients’ information files and compared to national antimicrobial prescribing guidelines to determine prescribers’ adherence. Qualitative semi-structured interviews were conducted with members of staff at MDH to determine whether antimicrobial stewardship (AMS) measures were adopted at the hospital. Results A total of 278 patients were included in this study, 12 of these were admitted twice during the study period. In total 290 admissions were analysed, with 659 antimicrobial medicines prescribed. The most common diagnoses were pneumonia (36.9%), acute gastroenteritis (20.7%), upper respiratory tract infections (3.4%), and bronchiolitis (3.1%). The most prescribed antimicrobials were ampicillin (21.4%), gentamicin (21.2%), and cefotaxime (8.3%). Adherence to guidelines was relatively good, with 82.7% of antimicrobials prescribed for the patients in the study having been prescribed in compliance with the national prescribing guidelines. The semi-structured interviews highlighted the fact that staff knew about AMS and AMR in general, however awareness of an AMS committee at MDH varied. The AMS committee was a multidisciplinary committee, which was a subcommittee of the Drugs and Therapeutics Committee (DTC). Discussion and Conclusion The results suggest that adherence to prescribing guidelines was relatively high compared to other paediatric antimicrobial utilisation studies in African countries. Prescribing of antimicrobial medicines was consistent with other African countries. The long period of time that it takes for microbiological test results to become available means that most prescribers rely on empirical prescribing. The antimicrobial committee is a multidisciplinary committee with defined roles for its members, consistent with international guidelines for implementing an AMS committee at a hospital. , Thesis (MPharm) -- Faculty of Pharmacy, Pharmacy, 2022
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Date Issued: 2022-04-06

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Academic or ‘zoombie’? Characterizing sleep quality, work and lifestyle behaviours among a cohort of South African academic staff during the Covid-19 pandemic

- Le Grange, Sarah-Ann

Authors: Le Grange, Sarah-Ann
Date: 2022-04-06
Subjects: Sleep-wake cycle South Africa Eastern Cape , Sleep Physiological aspects , Lifestyles Health aspects South Africa Eastern Cape , COVID-19 Pandemic, 2020- Influence , Work environment Psychological aspects , Work environment Physiological aspects , College teachers Workload South Africa Eastern Cape , Pittsburgh Sleep Quality Index (PSQI)‎
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/291099 , vital:56818
Description: Working in academe is characterized by high work demands, long and late working hours and balancing multiple roles. This often leaves academic staff (interchangeably referred to as ‘academics’ and ‘staff’) with limited time to prioritize adequate rest and sleep. While sufficient sleep is important for general well-being and work performance, it may be important for academics given the cognitive and interactive nature of their work. However, limited research has characterized sleep behaviours and sleep quality in academic staff globally and specifically in South Africa (SA). Further, research shows that academics from different academic ranks and genders differ in their work experiences but less is known about whether these factors affect their sleep and lifestyle factors. Over and above the demands of academic work, the current study was conducted during COVID-19, which saw unprecedented change in workloads for academic staff due to online teaching and learning. Additionally, the pandemic has been associated with poorer sleep quality and lifestyle behaviours in the general population, but very few studies have explored this in the context of academics. Thus, this study aimed to characterize the sleep quality, work and lifestyle factors among academics from a university in the Eastern Cape province of SA and determine the effects of gender and academic rank on these measures. Additionally, the study aimed to determine the impact of COVID-19 on sleep and work-related factors of this group. This study adopted a cross-sectional design and made use of an online questionnaire that was distributed to all academics employed at the institution via email. The data collection occurred over an 8-week testing period between August and September of 2020. The questionnaire explored sociodemographic, work and lifestyle characteristics, while the characteristics of sleep and sleep quality were explored with the Pittsburgh Sleep Quality Index (PSQI). Additionally, an open-ended section was included to determine the impact of COVID-19-related changes on sleep and work. The questionnaire responses were analyzed with descriptive and inferential statistics and the open-ended questions were analyzed with thematic analyses. A total of 84 respondents completed the questionnaire. On average, sleep quality was poor (global score of 7.09 ± 3.8), the reported sleep duration was short (6.41 ± 1.06 hrs) and the group was classified as overweight according to median BMI (26.67 [23.8-2 29.45] kg/m2). Over a third (35.71%) of academic staff reported not meeting physical activity guidelines and reported using screens one hour prior to bed every night during the week (76.19%) and the weekend (67.88%). Staff also worked long total weekly work hours (54.25 ± 11). Female academics had a poorer sleep quality (p = 0.035), spent a longer time in bed (p = 0.04), experienced more bad dreams (p = <0.01), had their last serving of alcohol earlier (p = 0.04) and worked less weekday (p = 0.04) and less total weekly (p = 0.02) hours compared to male academics. Professorship-level academics were significantly older than junior- and senior-level academics (p = <0.01) while senior-level academics had a poorer PSQI compared to professorship-level academics (p = 0.03). The thematic analysis showed that home environment, neighbourhood noise, work and mental health were the main emerging factors that disturbed sleep. The thematic analysis showed that, in relation to the impact of COVID19, sleep schedules changed and sleep duration and sleep quality improved or got worse. Respondents reported their work hours increasing, work schedules becoming less routine while working from home, dealing with the challenges of working online and experiencing worry, stress and anxiety due to the pandemic. The study highlights that, in the context of lockdown and having to work and teach online from home, academics reported poor quality sleep and short sleep duration. Further, on average, the sample reported working extensive hours and unhealthy lifestyle behaviours. The sleep health, nature of work and overall lifestyles of academic staff deserves more research attention, given the importance of their work and the impact that inadequate sleep could have on academics’ health and work performance. Sleep quality was worse for females and mid-career academics, suggesting that their sleep quality may be at greater risk than other sub-groups. However, the reasons for these differences need to be explored in future studies. The findings contribute to the narrative that academe involves numerous demands and supports previous research that has suggested that academics’ sleep is insufficient. Furthermore, COVID-19 had an impact on staff’s sleep, with staff reporting changes in their sleep quality and duration. The pandemic impacted work of academics by presenting novel demands related to online teaching, intensifying demands overall and disrupting work routines. However, future research is needed to understand academics’ sleep behaviours, work and lifestyles, especially in South Africa. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
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Date Issued: 2022-04-06

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Adolescents and coaches/trainers perspectives of ergogenic sports supplement use within South African private high schools

- Butler, Nicholas John

Authors: Butler, Nicholas John
Date: 2022-04-06
Subjects: Dietary supplements , Energy metabolism , Teenagers South Africa , Teenagers Physiology South Africa , Teenagers Substance use South Africa , Coaches (Athletics) South Africa , Athletic trainers South Africa , Private schools South Africa , Ergogenic aids‎
Language: English
Type: Master's thesis , text
Identifier: http://hdl.handle.net/10962/232443 , vital:49992
Description: Sports supplements, also referred to as ergogenic aids, are used because of the assertion that they can enhance physical or athletic performance and/or physical appearance. Commonly used sports supplements include creatines, proteins, amino acids, stimulants, and in some cases pro-hormones. There is a relatively high and increasing prevalence of sports supplement use by the general population globally and in South Africa, particularly among adolescents and young adults due to various factors. While some research has explored supplement use among adolescents in a school setting, no study has explored this across the private school system in South Africa. Additionally, given the important role that coaches/trainers play in adolescent development, it is critical to also understand the role that they play regarding adolescent supplement use, given that there has been limited research around this topic in South Africa. Therefore, there were two aims of this study; Firstly, this study explored the prevalence and perceptions (knowledge; attitudes; beliefs) of sports supplements among South African private high school adolescents. Secondly, this study explored the perceptions (knowledge; attitudes; application of knowledge) towards sports supplements among adolescent coaches/trainers in South African private high schools. Considering the dual aim of this study, this thesis was structured as a two-part research study. Both parts took the form of a cross-sectional design, using an online questionnaire to collect qualitative and quantitative data. In total, a cohort of n=50 adolescents and n=49 coaches/trainers participated. Adolescent participants reported a high prevalence of sports supplement use (62%) with their main reasons for using them being recovery and performance. Adolescents were primarily influenced/advised by friends and coaches/trainers to start using sports supplements. Coaches/trainers primarily relied on other coaches/trainers and internet advertising/sites as a main source of information. Less than half of the participants from both groups reported having any formal education or training related to sports nutrition or sports supplements. Both groups thought that these products are being misused by adolescents, which may account for why a portion of the adolescent participants reported experiencing adverse side-effects from using sports supplements, and a few coach/trainer participants reported witnessing this in their practice. This may be a result of the professionalisation of school sport which places pressure on athletes and their coaches/trainers to perform and may in turn be the reason why some adolescents reported that they would use, and some coaches/trainers reported they would recommend the use of sports supplements even if they were aware of risk/dangers involved. Thus, there is a need for education/training among South African high school adolescents and their coaches/trainers with respect to the use of sports supplements, so that they can make informed decisions from reliable sources of information or advice in order to use these products safely and effectively. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
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Date Issued: 2022-04-06

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An investigation into stakeholder inclusivity and the board’s ability to create competitive advantage at South Africa’s “big five” retail banks

- Wolhuter, Darren Wilfred

Authors: Wolhuter, Darren Wilfred
Date: 2022-04-06
Subjects: Stakeholder management South Africa , Strategic planning South Africa , Banks and banking South Africa , Corporate governance South Africa , Competition , Resource-based theory‎
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/284548 , vital:56073
Description: Stakeholder theory has long put forth the concept that managerial attention must be given to all stakeholders towards the realisation of value creation opportunities. Through the process of stakeholder engagement, and through the adoption of stakeholder inclusivity principles, an organisation can position itself to reap the benefits of understanding the legitimate needs and interests of all its stakeholders by seeking to satisfy all its stakeholders in turn. This study analysed the integrated reports of five retail banks, whose main base of operations were in South Africa, to assess the board’s ability to create value for its stakeholders through adopting a stakeholder inclusive approach to corporate governance as advocated for by the King Code on Corporate Governance in South Africa – King IV™. This assessment was done through an examination of a selection of outcomes relevant to the banking industry and related to each of the six capitals that form part of the value creation process as indicated for in the Integrated Reporting Framework (IIRC, 2013): 1) Financial Capital, 2) Manufactured Capital; 3) Intellectual Capital; 4) Human Capital; 5) Social and Relationship Capital, and; 6) Natural Capital. The results obtained, over a three-year period – 2018 to 2020, revealed that while the directors had a firm understanding of who their material stakeholders were, they struggled to create value that catered to all their stakeholders collectively. In addition, the directors were also unable to create sustainable value over the assessment period. As a result of this, most banks, with the exception of one, were unable to realise the value creation opportunities that could have led to a potential source of competitive advantage. The study concludes that while no observable sustainable competitive advantage was evident over the period of assessment, the concept of stakeholder inclusivity is an important corporate governance principle that drives value creation and, as such, warrants more attention from the director’s point of view. This research is intended to contribute to the growing knowledge on the importance of stakeholder inclusivity in corporate governance execution. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
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Date Issued: 2022-04-06

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An investigation into the force-EMG relationship for static and dynamic exertions

- Koekemoer, Wesley Agosthinho

Authors: Koekemoer, Wesley Agosthinho
Date: 2022-04-06
Subjects: Electromyography , Force and energy , Muscles Physiology , Biomechanics , Muscle contraction , Isometric exercise , Isotonic exercise , ‎Static and dynamic exertions
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/291076 , vital:56816
Description: The force-EMG relationship has multiple applications in varying fields of study and practice. One such application is the development of safety guidelines and regulations. Current guidelines are based on static muscle actions even though the majority of tasks encountered in industry are dynamic in nature. This may have negative implications for the health, safety, and productivity of workers as regulations based on static muscle actions may place higher force demands on manual labourers compared to what would be expected if regulations were based on dynamic muscle actions. Regulations based on dynamic muscle actions may be more effective in worker safety as the nature of the regulation matches that of the demand. Few studies have investigated the force-EMG relationship during dynamic muscle actions and the few that do exist have reported contradictory / mixed results. Therefore, the purpose of this study was to: 1) gain an understanding of EMG responses at different load levels, and 2) show how the relationship differs between static and dynamic muscle actions. A two-factorial repeated-measures experiment was developed for this study. Eighteen experimental conditions, utilizing six load levels (0%, 20%, 40%, 60%, 80%, and 100% of maximum voluntary force) for each of the three muscle actions (isometric, concentric and eccentric). Surface EMG responses were obtained under these conditions by repeatedly dorsiflexing and plantarflexing the foot, thus activating the soleus muscle. A maximum voluntary exertion on an isokinetic dynamometer determined the maximum force level, based on which the sub-maximal loads were calculated and added to a pulley system. 31 student participants were recruited for this experiment which was conducted over two sessions – one information and habituation session, and one experimental session. The EMG data recorded were processed and checked for normality and outliers. The data was then analysed via a General Linear Model analysis to determine the effect of exertion type and of load level on the muscle activity. Significant differences were identified at p<0.05 and followed by a Tukey post-hoc test. Correlation analyses were also conducted to determine the relationship between the force and EMG at all three exertion types. All dependent measures showed that as the load level increased so did the sEMG amplitude for all muscle actions. Muscle actions differed significantly between majority of six force levels. Correlations between the load levels and sEMG amplitude for each muscle action indicated a significant correlation with a moderate strength. The conclusion draws from this study that there is a positive correlation between force and sEMG amplitude, at all load levels, with a moderate strength. However, the muscle actions differed significantly from each other. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
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Date Issued: 2022-04-06

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Antimalarial activity of quinoline thiosemicarbazones: synthesis and antiplasmodial evaluation

- Nqeno, Lukhanyiso Khanyisile

Authors: Nqeno, Lukhanyiso Khanyisile
Date: 2022-04-06
Subjects: Uncatalogued
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/291292 , vital:56841
Description: Africa is one of the regions that is most affected by malaria, as 90% of all malaria deaths occur in sub-saharan Africa. Malaria is a life threatening disease responsible for an estimated 800000 deaths each year, the majority of these deaths occurred in children under the age of five. The disease is a mosquito-borne, and it is transmitted to humans by the female Anopheles mosquito. The parasite responsible for this disease belong to the Plasmodium genus with Plasmodium falciparum causing the most severe cases of the disease in humans. The most widely available anti-malarials were designed to specifically target the pathogenic blood stage in humans, however, in order to completely eradicate malaria there is a need for the development of medicines that not only target the pathogenic blood stage of the parasite but also block parasite transmission and eliminate asymptomatic and cryptic hepatic forms of the parasite. Iron chelators have recently gained importance as potent antimalarials, to cause infection nearly all protozoa obtain growth essential iron from their hosts. Iron is required for the development of the parasite. Deprivation of utilizable iron by chelation is a proficient approach to arrest parasite growth and associated infection. Thiosemicarbazones are known iron chelating agents by bonding through the sulfur and azomethine nitrogen atoms. This study is aimed at the identification of thiosemicarbazone based derivatives as possible antimalarial agents. Due to their iron chelation abilities there has been increasing interest in the investigation of thiosemicarbazones as possible antimalarials. During the course of this project, several thiosemicarbazone derivatives were synthesized and their structure confirmed using routine analytical techniques (NMR, FTIR, and HRMS). The synthesized compounds were evaluated in vitro against the chloroquine sensitive strain (3D7) of P. falciparum for antimarial activity. The compounds were also evaluated agsinst Hela cells for overt cytotoxicity. The compounds generally showed poor antimalarial activity. One compound (LKN11) was identified to possess intrinsic and moderate antimalarial activity of 6.6 μM. The compounds were generally not cytotoxic against Hela cell at concentrations of up to 20 μM, with only compound LKN10 showing modest cytotoxic activity of 9.5 μM. This research went on to identify two thiosemicarbazone based derivatives which had a significant effect on HeLa and pLDH cells. , Thesis (MSc) -- Faculty of Science, Chemistry, 2022
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Date Issued: 2022-04-06

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Assessing the density and distribution of spotted hyaenas (Crocuta crocuta) in Hluhluwe–iMfolozi Park, KwaZulu-Natal, South Africa

- Roberts, Peter Jean

Authors: Roberts, Peter Jean
Date: 2022-04-06
Subjects: Uncatalogued
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/292681 , vital:57006
Description: Protected areas are becoming increasingly isolated refugia for large carnivores and are critical for their survival. Spotted hyaenas (Crocuta crocuta) have, for centuries, been ‘managed’ as problem causing animals and their conservation has been largely overlooked. To preserve a population, it is paramount to understand its distribution and abundance through reliable and cost-effective monitoring techniques. My study estimated the density of spotted hyaenas and their use of space in Hluhluwe–iMfolozi Park (HiP), South Africa. I compared camera trap by-catch data and call-up surveys between 2013–2018 to assess spotted hyaena densities. The camera trap data estimated an average of 16.72 (SD: ±2.22) hyaenas per 100 km2 between 2013–2018, with an annual estimated high of 19.01 in 2018 and a low of 12.77 in 2015. The call-up surveys consistently produced lower estimates than those obtained from the camera trap data. These results highlight the importance of calibrating the response probability factor for call-up surveys to maintain precision. The space use of spotted hyaenas was analysed using the photo-capture data obtained during the same six-year period, to produce individual 100% Minimum Convex Polygon’s (MCPs). Seven clan territories were identified from individual female home ranges that overlapped by more than 66% of their MCPs. Territory sizes were similar to historical estimates for the park, with averages of 13.96 (SD: ±6.48) km2 in Hluhluwe and 34.61 (SD: ±23.87) km2 in iMfolozi. My study successfully used by-catch camera data to calculate annual density estimates and investigate the spatial use patterns for spotted hyaenas in HiP. I demonstrate that this approach is cost-effective and reliable for calculating density estimates. Conservation practitioners should take heed of the advancements in technology and analytical capacity now available to them to improve monitoring efforts. My study specifically calls for collaborative efforts to use existing camera trap data to improve regional estimates and population trends of spotted hyaenas across their range. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
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Date Issued: 2022-04-06

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Bond market integration in the Common Monetary Area (CMA)

- Ramoriting, Retšelisitsoe Silvia

Authors: Ramoriting, Retšelisitsoe Silvia
Date: 2022-04-06
Subjects: Globalization , Globalization Economic aspects , Bond market , Rand area , Africa, Southern Economic integration , ‎Autoregressive distributed lag (ARDL) model
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/284592 , vital:56077
Description: The study reviews the phenomenon of financial integration. During the late 1980s and 1990s, financial market integration around the world increased due to globalisation of investments and the need for higher returns and international risk diversification. The increase was accompanied by a significant increase in private capital flows into developing countries from developed countries. The main goal of the study is to examine bond market integration in the common monetary area The study therefore investigates the co-movement of government bond returns within the CMA using data from Eswatini, Namibia, and South Africa. The study attempts to find the short-run and long-run relationship of these government bond returns using the ARDL cointegration technique. The study uses daily data of 10-year government bond yields spanning from August 2014 to September 2019. The empirical results reveal that there exists a short-run and long-run relationship between South Africa and Eswatini. Between South Africa and Namibia, there only exist a short-run relationship. Just like the previously mentioned studies, the short-run relationship is a result of policy convergence. The lack of long-run relationship between South and Namibia was due to poor institutional developments and limited investment opportunities. In this case, policy measures (or reforms) and a review of the union are necessary to increase integration of these bond markets. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
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Date Issued: 2022-04-06

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Cloning, expression, partial characterisation and application of a recombinant GH10 xylanase, XT6, from Geobacillus stearothermophilus T6 as an additive to chicken feeds

- Sithole, Tariro

Authors: Sithole, Tariro
Date: 2022-04-06
Subjects: Uncatalogued
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/292693 , vital:57007
Description: Monogastric animal farming has largely been sustained by feeding animals with grain feedstocks containing non-starch polysaccharides (NSPs) and anti-nutritive factors, which cause adverse effects, such as increased digesta viscosity and entrapment of nutrients, which leads to the inaccessibility of nutrients. These effects have been linked to a reduction in nutrient digestion and absorption, which results in a decreased feed conversion ratio, energy metabolism and animal growth. Monogastric animals do not produce enzymes that can hydrolyse these NSPs. The application of exogenous enzymes as supplements to animal feeds has been implemented to reduce viscosity and increase nutrient absorption in poultry and pigs over the past few decades. The aim of this study was to clone, express, partially characterise and apply a glycoside hydrolase (GH) family 10 xylanase (XT6), derived from Geobacillus stearothermophilus T6, as an additive to locally produced chicken feeds. The xt6 gene (1,236 bp) was subcloned and expressed in Escherichia coli DH5α and BL21(DE3) cells, respectively. Upon expression, XT6 had a molecular weight of 42 kDa and was partially purified by Ni-NTA chromatography and ultrafiltration. The purification step resulted in a yield of 66.7% with a 16.8-fold increase in purification. XT6 exhibited maximal activity when incubated at a pH and temperature of pH 6.0 and 70°C, respectively, with a high thermostability over a broad range of pH (2–9) and temperature (30–90 °C). The specific activities of XT6 on extracted soluble and insoluble wheat flour arabinoxylans were 110.9 U/mg and 63.98 U/mg, respectively. Kinetic data showed that XT6 displayed a higher catalytic activity and affinity (Vmax = 231.60 μmol/min/mg and KM = 2.759 mg/ml) for soluble wheat arabinoxylan, compared to insoluble wheat arabinoxylan (Vmax = 99.02 μmol/min/mg and KM = 5.058 mg/ml). High-performance liquid chromatography (HPLC) analysis showed that the enzyme hydrolysed wheat flour, arabinoxylan and chicken feeds, producing a range of xylooligosaccharides (XOS), with xylotetraose and xylopentaose being the predominant XOS species. Hydrolysis of both soluble and insoluble wheat flour arabinoxylans by XT6 led to a significant reduction in substrate viscosity. The effects of simulated gastrointestinal fluid contents, such as proteases, bile salts and mucins, on XT6 stability were also studied. Exposure of XT6 to pepsin did not significantly reduce its activity; however, the inhibitory effect of trypsin and mucin on XT6 was much greater. The presence of gut-derived bile salts had no iii | P a g e significant effect on XT6 activity. Finally, it was shown that the XOS produced from the hydrolysis of chicken feeds (starter and grower feeds) by XT6 significantly enhanced the growth of the probiotic bacteria B. subtilis, while there was no significant improvement in the growth of S. thermophilus and L. bulgaricus. In conclusion, the recombinantly produced XT6 demonstrated efficient hydrolysis of starter and grower feeds, and produced XOS that showed prebiotic activity on selected probiotic bacteria. In addition, the pH, temperature and simulated gastric juice content stability of XT6 renders it an attractive candidate as an additive for chicken feeds. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
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Date Issued: 2022-04-06

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Exchange rate volatility and the returns on diversified South African investment portfolios

- Mulamu, Murendeni

Authors: Mulamu, Murendeni
Date: 2022-04-06
Subjects: Foreign exchange rates South Africa , Rate of return , Investments , GARCH model , Regression analysis , ‎Autoregressive distributed lag (ARDL) model
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/284581 , vital:56076
Description: Globalisation has made it much easier to invest in foreign countries. This creates endless options accessible to investors, including exploiting opportunities for investment in international economies. Although foreign investment portfolio diversification provides significant opportunities for financial returns, exchange rate volatility may play a prominent role when investing in foreign markets. Since the introduction of a floating exchange rate system, together with the inflation-targeting monetary policy framework in South Africa, there has been significant volatility in the exchange rate, far more than during the previous dispensations. This, however, creates a strong need to consider how the unpredictable nature of the exchange rate affects these investments. The purpose of this study is to analyse the effect of exchange rate volatility on the returns on diversified South African investment portfolios. This research examined whether there is a homogenous relationship between South African (domestic) portfolios and the internationally diversified portfolios. In addition, the study investigated the long-run relationship between the exchange rate volatility and both domestic portfolios and the internationally diversified portfolios for the period 2007-2019. To achieve these goals, a panel ARDL model was employed. This study found that exchange rate volatility does not account for a significant portion of returns on investment portfolios fluctuations. Moreover, the relationship is not homogenous because returns on domestic investment portfolios react positively to the exchange rate volatility, whereas returns international investment portfolios respond negatively/positively to the exchange rate volatility depending on whether the relationship is short or long run. This study will contribute to the existing literature, and it is important for investors intending to diversify their investment portfolios both domestically and internationally using different mutual funds in South Africa. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
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Date Issued: 2022-04-06

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Exploring the entrepreneurial intention of students in one Higher Education Institution (HEI)

- Kenye-Duma, Ayanda Rachel

Authors: Kenye-Duma, Ayanda Rachel
Date: 2022-04-06
Subjects: Entrepreneurship South Africa , Intention , Entrepreneurship Study and teaching (Higher) South Africa , Students Attitudes , Social entrepreneurship , Social capital (Sociology) , Unemployment South Africa , Entrepreneurship Development in Higher Education (EDHE)‎
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/284514 , vital:56070
Description: This study was interpretive and qualitatively explored students' entrepreneurial intentions at Rhodes University. It was conducted to understand entrepreneurship among students. Understanding students' entrepreneurship is critical as entrepreneurship is touted as a reasonable response to alleviate the high unemployment in South Africa. The study explored how students became entrepreneurs (or how their entrepreneurship intentions were formed) and the factors that enhanced (enablers and barriers) and inhibited them. The significance of living with and after COVID-19, youth and graduate unemployment alleviation places entrepreneurship development by institutions of higher learning, governments and private sector in the centre of economic recovery. The establishment of the Entrepreneurship Development in Higher Education (EDHE) in 2016, highlights the commitment of the South African government, for Higher Education Institutions (HEI) to engage more in entrepreneurship and do more research to understand how students become entrepreneurs and unravel the challenges. Understanding students' entrepreneurship intentions can facilitate a supportive environment for students entrepreneurship. With “very little research about student entrepreneurship at this university” being the guiding research problem, the aim was to gain insight into the entrepreneurship intention of university students by exploring factors that influence students to become entrepreneurs. The study employed Ajzen’s Theory of Planned Behaviour to explore the entrepreneurial intentions of university students in terms of the underlying attitudes, subjective norms, and perceived behavioural control. The students who participated in the study fell into three categories of entrepreneurial intention: (i) Intending to start a business, (ii) starting a business, and (ii) those who were already operating a business. All the participants, irrespective of their stage of entrepreneurial intention, demonstrated a positive attitude and self-efficacy. All participants showed self-efficacy by identifying barriers and taking positive steps to overcome them. The main barriers were access to funding, capital, training, business opportunities with the university and lack of interaction with established entrepreneurs. The results demonstrated the close interplay of attitudes, social norms and perceived behavioural control in students’ entrepreneurial intentions. Social recognition of entrepreneurship, social capital, education and role models contributed to positive attitudes, and social norms influenced students’ entrepreneurial intentions. A supportive environment was found to be critical for nurturing entrepreneurship intentions. The study recommends a supportive climate cultivated by Rhodes University to promote entrepreneurship. The supportive environment must include the elevation of entrepreneurship in prominent offices of the university, strengthening entrepreneurship societies and interactions with established entrepreneurs, and engagement with the private sector to contribute and promote entrepreneurship among students. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
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Date Issued: 2022-04-06

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Fabrication and characterization of ciprofloxacin loaded niosomes for transtympanic delivery

- Mhlanga, Asavela

Authors: Mhlanga, Asavela
Date: 2022-04-06
Subjects: Drug delivery systems , Liposomes , Ciprofloxacin , Quinolone antibacterial agents , Drug carriers (Pharmacy) , Drug stability , Lamellarity‎ , Niosomes‎
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/290715 , vital:56777
Description: Ciprofloxacin (CPH) is a broad-spectrum antibiotic used to treat bone, joint, and skin infections. It is commercially available as an extended-release tablet and as a cream dosage form. CPH is a bactericidal active pharmaceutical ingredient (API) of the fluoroquinolone drug class. It inhibits deoxyribonucleic acid (DNA) replication by inhibiting bacterial DNA topoisomerase and DNA gyrase enzymes. Common adverse effects include nausea, vomiting, unusual fatigue, pale skin, and may increase the risk of tendinitis, which could be a major concern. CPH is, according to the Biopharmaceutics Classification System (BCS), classified as a BCS class IV drug exhibiting low oral bioavailability, low solubility, and intestinal permeability. CPH was chosen as a good candidate for the study because of its stability in solutions, its low molecular weight (331.4 g/mol), and its moderate lipophilicity (log P = 0.28) [16]. The use of conventional ear drops in the ear is effective, avoids hepatic first metabolism and extensive protein binding and may reduce adverse effects as a low dose may be used to achieve a therapeutic effect. However, conventional ear drops and oral antibiotics have a long onset of action and have to be taken/applied in short intervals. For convenience and assurance of a long residence time in the ear, CPH may be delivered by using a niosomal formulation, a liquid at room temperature, to allow administration into the ear without the need to constantly apply the ear drops for long periods of time. A simple, rapid, precise, accurate, reproducible, and specific reversed-phase high-performance liquid chromatography (RP-HPLC) method using ultraviolet (UV) detection for the quantitation of CPH was developed and optimized using a central composite design (CCD). The method was validated using International Conference on Harmonisation (ICH) guidelines and was found to be linear, precise, accurate, and specific for the analysis of CPH. Since the method is specific, it was used to quantify CPH in commercial and experimental formulations and monitor CPH released during in-vitro release testing. The compatibility of CPH and potential excipients was investigated during preformulation studies using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) to identify and select suitable excipients for use during formulation development activities. No apparent interactions were evident between CPH, and the excipients tested. The probe sonication method was used to manufacture CPH loaded niosomes using different surfactants/surfactant combinations, and a combination of Tween® 80: sodium lauryl sulfate (SLS) was found to be the best composition in terms of both entrapment efficiency and Zeta potential. The limits for the independent input variables used for the manufacture included amplitude, sonication time, and amount of cholesterol were determined. Design of experiments (DOE) was used to design the study. The input variables investigated included amplitude, amount of cholesterol, and sonication time. The output or responses monitored included Zeta potential, vesicle size, polydispersity index (PDI), and entrapment efficiency. Non-ionic surfactant systems are predominantly stabilized by steric stabilization, and there is only a minor electrostatic element from adsorbed hydroxyl ions. With the inclusion of SLS it is to be expected that Zeta potential will be a contributing factor. DOE using Box-Behnken design (BBD) and response surface methodology (RSM) in addition to Artificial Neural Networks (ANN) were used for the optimization of the formulation. The optimized formulation had a composition of 1 g cholesterol, 1 g of Tween® 80, 1 g of SLS and was prepared at an amplitude of 11.294 % with a sonication time of 3.304 minutes. The formulation exhibited zero-order release kinetics and had an average pH of 7.45. The formulation was stored at 4 ℃ and 25 ℃ and was assessed for vesicle size, entrapment efficiency, Zeta potential, colour, lamellarity, and PDI every 7 days for 4 weeks. The lead formulation stored at 4 ℃ was more stable than the formulation at 25 ℃ in terms of entrapment efficiency, PDI and vesicle size during the 4-week period. CPH loaded niosomes for transtympanic delivery in the treatment of otitis media were developed and optimized. The technology exhibits sustained release of CPH and has the potential for further development and optimization. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2022
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Date Issued: 2022-04-06

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Influence of argon ion implantation on the thermoluminescence properties of aluminium oxide

- Khabo, Bokang

Authors: Khabo, Bokang
Date: 2022-04-06
Subjects: Aluminum oxide , Thermoluminescence , Ion implantation , ‎Kinetic analysis , ‎Oxygen vacancies , Argon , Irradiation
Language: English
Type: Master's thesis , text
Identifier: http://hdl.handle.net/10962/234220 , vital:50173
Description: The influence of argon ion implantation on the thermoluminescence properties (TL) of aluminium oxide (alumina) was investigated. Aluminium oxide (Al2O3) samples were implanted with 80 keV Ar ions. An unimplanted sample and samples implanted at fluences of 1×1014, 5×1014, 1×1015, 5×1015, 1×1016 Ar+/cm2 were irradiated at a dose of 40 Gy and heated at a rate of 1°C/s using a Risø reader model TL/OSL-DA-20 equipped with a Hoya U-340 filter. The thermoluminescence glow curves showed five distinct peaks with main peaks at 178°C, 188°C, 176°C, 208°C, 216°C and 204°C for the unimplanted sample as well as implanted samples. The peak positions of the samples were independent of the irradiation dose suggesting that the samples were characterised by first order kinetics. This was also confirmed by the TM-TSTOP analysis. It was observed that the TL intensity decreases with fluence of implantation. This observation suggests that the concentration of electron traps responsible for thermoluminescence decreases with ion implantation. The decrease in electron concentration might be due to the formation of non-radiative transition bands or the creation of defect clusters and extended defects following the ion implantation and ion fluence increases. The stopping and range of atoms in matter (SRIM) program was used to correlate the TL response of Al2O3 with defects under ion implantation. Subsequent to ion implantation, it was found that the number of oxygen vacancies which are related to electron traps are higher than the number of aluminium vacancies. Kinetic analysis was carried out using the initial rise, Chens peak shape, various heating rate, the whole glow curve, glow curve fitting and the isothermal decay methods. The activation energy was found to be around 0.8 eV and the frequency factor to be of the order 108 𝑠−1 regardless of the implantation fluence. This means that argon ion implantation did not affect the nature of electron traps. The dosimetric features of samples were also investigated at doses in the range of 40 – 200 Gy. Samples generally showed a superlinear response at doses less than 140 Gy and sublinear response at doses higher than 160 Gy. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2022
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Date Issued: 2022-04-06

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Institutional innovations for improved water security in smallholder irrigation schemes in KwaZulu-Natal and Eastern Cape Provinces, South Africa

- Phakathi, Sandile

Authors: Phakathi, Sandile
Date: 2022-04-06
Subjects: Water security South Africa , Rural development projects South Africa , Institutional cooperation South Africa , Irrigation farming South Africa , Food security South Africa , Agricultural innovations South Africa , Irrigation Technological innovations South Africa , Smallholder irrigation schemes‎
Language: English
Type: Doctoral thesis , text
Identifier: http://hdl.handle.net/10962/232341 , vital:49983 , DOI 10.21504/10962/232341
Description: Smallholder irrigation schemes are regarded as a key strategy to eliminate poverty and increase food security in rural areas in South Africa. While the South African government has invested heavily in rural development schemes, most irrigation schemes face a myriad of challenges, including deficient infrastructure, weak institutional arrangements and water insecurity. Weak institutions have been identified as a major bottleneck in the performance of smallholder irrigation schemes in developing countries, including South Africa. Two main reasons have been identified for this challenge. Firstly, the agency of the irrigators was ignored during the design of the schemes. Treating farmers as passive rather than active agents resulted in institutional arrangements that were not context-specific, as well as weak farmer commitment to the ownership and management of the schemes, leading to system breakdown. Despite being noble in intention or design, institutions designed by outsiders often fail due to a lack of legitimacy. Secondly, institutions have failed to evolve to cope with dynamic challenges and opportunities in the sector. Stability over a reasonable period is required for institutions to effectively perform their crucial role of establishing reasonable expectations in dealings among people. Institutional innovations are required to keep up with the changing nature of development. In particular, farmer-led institutional innovations have been touted as key to improving the management of water resources in irrigation schemes. Farmer-led institutional innovation refers to a process, in which farmers themselves initiate, establish, and improve institutions based on their context-specific challenges or opportunities. Farmers’ groups are regarded as an important institutional arrangement to reduce transaction costs, improve social networks, and increase livelihood outcomes. However, little is known about the internal dynamics of these farmer groups, how they operate, and whether or not they are inclusive and innovative, as well as what makes certain groups more successful than others. Furthermore, there is a paucity of research on whether these farmer groups embrace institutional innovations to improve water security and strengthen their design principles that are crucial for collective action. It is against this background that this study aimed to examine the internal group dynamics within the farmer groups; determine whether smallholder farmers are capable of implementing institutional innovations that are novel, useful and legitimate; determine the nature of these innovations (incremental or radical) and their role in improving water security. The main theories that underpinned the study were induced institutional innovation theory, collective action theory, random utility theory and Ostrom’s eight design principles. Multistage sampling was used to collect data from 28 farmer groups and 401 irrigators in smallholder irrigation schemes in KwaZulu-Natal (Tugela Ferry and Mooi River) and the Eastern Cape (Qamata and Zanyokwe). Data were gathered by means of focus group discussions, key informant interviews and household surveys. Several empirical tools were employed to analyse the data (descriptive statistics, thematic analysis, logit model, propensity score matching, PCA and OLS). The study found that group membership was associated with higher levels of water access, adoption of inorganic fertiliser, incomes and assets. Group members had an additional four days’ access to water in a month and applied at least 130 kg/ha more inorganic fertiliser than non-group members. Group members also had a higher household income per capita and more assets than non-group members. However, the results revealed a heterogeneous effect among group members, with the benefits varying according to members’ socio-economic characteristics as well as internal group dynamics. The results suggest that organising farmers into groups should be promoted to improve farmers’ access to productive assets such as water, technology adoption and welfare outcomes. However, the study findings also indicate that smaller groups should be promoted, programmes targeted at empowering women should be prioritised, and that it is imperative to invest in improving farmers’ human capital through various training initiatives. The results indicated that farmers could develop and implement institutional innovations that are novel, useful and legitimate. Of the 28 groups, 21 (75%) had implemented institutional innovations in the past three years. Examples of innovations include, among others, the introduction of a secret voting system to improve marginalised people’s participation in decision-making processes, designing daily rotation rosters to reduce conflict, using an attendance register for participation in group activities, and rewarding members according to their participation levels. Most of these innovations were designed to improve the graduated sanction mechanism (22.2%), enhance the penalty system for non-compliance; improve collective action arrangements (27.8%); monitor attendance of group meetings (18.5%); democratise decision making; and ensure equitable water distribution. However, they mainly focused on addressing challenges rather than exploiting opportunities and were largely incremental (94%), involving an adjustment or reinterpretation of rules and regulations. Furthermore, the innovative groups were small in size and were dominated by male farmers. Based on these results, it is recommended that the government should build on the irrigators’ agency to improve the effectiveness and legitimacy of institutional arrangements in irrigation schemes. The findings also suggest that small groups should be actively promoted, while tailored training should be offered based on the groups’ specific needs to improve institutional innovations in the smallholder irrigation sector in South Africa. A positive association was established between belonging to an innovative group and water security, highlighting the importance of institutional innovations in water security. The propensity score matching indicated that water secure irrigators produced an additional 569-622 kg of maize and earned additional income of R2 037.81. The study’s findings suggest that organising farmers into groups is a promising strategy to improve farmers livelihoods and water security. The government and private donors should thus continue to promote the formation and organisation of farmers into groups. The innovative agency of the irrigators should be acknowledged and harnessed to strengthen institutional innovations. The focus should be on strengthening the institutions designed by farmers themselves, as these are locally contextualised and socially embedded, and hence legitimate. It is recommended that small groups should be actively promoted, while tailored training should be offered based on groups’ specific needs to improve institutional innovations in the smallholder irrigation sector in South Africa. , Thesis (PhD) -- Faculty of Commerce, Economics and Economic History, 2022
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Date Issued: 2022-04-06

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