11613 research outputs found
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The impact of improper waste disposal on human health and the environment: a case of Umgungundlovu District in KwaZulu Natal Province, South Africa
No full text: Waste generation has increased drastically around the world in recent decades, with less than 20% of waste recycled each year, and one-third of all food produced wasted. With Sustainable Development Goal 12 advocating for changing how we consume, produce, and dispose of items, the cruciality of driving a more sustainable future lies in how we dispose of our waste.
: This study assessed the impacts of improper waste disposal on human health and the environment in the KwaZulu Natal Province of South Africa. The study applied a mixed-method pragmatic research approach, using Statistical Package for Social Scientists, and applied a series of Chi-Squared tests of independence, regression, and descriptive statistics to analyse data. This study has shed light on the complex dynamics surrounding the respondents’ awareness and perception of risks associated with improper waste disposal.
: While a fair level of knowledge exists concerning the general risks, there are notable gaps in understanding specific aspects of human health risks related to improper waste disposal. Furthermore, the study findings highlight a critical disparity in awareness regarding specific human health risks associated with improper waste disposal.
: This study has shed light on the complex dynamics surrounding the respondents’ awareness and perception of risks associated with improper waste disposal. This underscores the importance of enhancing public education and outreach programs to ensure a comprehensive understanding of the potential dangers to human health. The study municipality should explore sustainable waste management practices to mitigate the economic burden posed by increased waste generation.Publisher's versio
Alternatives to establishing conducive learning environment (AECLE) model for schools: assertive discipline perspective
No full textEffective classroom management necessitates a continuous adaptation of teachers' tactics, due to the dynamic nature of the classroom, which comprises learners from diverse backgrounds. These individuals are influenced by the continuous changes that occur in response to the dynamic nature of the world. This paper presents a conceptual model framework for managing learner classroom indiscipline. This model is derived from a theoretical framework that was adopted during an empirical investigation, carried out in four Quintile 3 secondary schools in South Africa. The paper exclusively concentrates on a literature review of empirical studies pertaining to indiscipline in South African secondary schools, the studies that either adopted or explored the implementation of the assertive discipline model and relevant South African education legislation and reports from government websites. Based on assertive discipline theory, the alternatives to establishing a conducive learning environment model offers alternate solutions for managing learners' behavioural issues. The core component of the strategy focuses on proactive behaviour management strategies that encourage the school to take full responsibility for student conduct and disregard extraneous influences. The model emphasises implementing a behaviour management strategy that encompasses the articulation of expectations, the establishment of classroom rules, the communication and instruction of these rules to learners, the demonstration and reinforcement of desired behaviour, and the utilisation of consequences.Publisher's versio
Crop systems for sustainable agriculture in the North-Western Free State, South Africa
No full textThesis (Ph.D.(Sustainable Agriculture))--University of the Free State, 2024: The North-Western Free State is a main contributor of South Africa’s maize production which has recently been put under enormous pressure by climate change, pests, diseases, economic factors and population growth. Crop diversification, by means of crop rotation, has potential to alleviate some of the challenges faced by the farmers and communities in the area. However, the effects of crop rotation are known to be site-specific. Therefore, the aim of this study was to determine the views and perspectives of local farmers on crop diversification as well as to determine the sustainability (in terms of soil health, nutrition, production and profitability) of different rotational systems specifically in the North-Western Free State.
: An interdisciplinary approach of social and natural science was taken to achieve the aim of this study. A unique questionnaire was designed, distributed and analysed to determine the views and perspectives of the local farmers on crop diversification. A field trial comparing different crop rotational systems was established on the farm Christinasrus and monitored for three consecutive seasons (2020/2021, 2021/2022 and 2022/2023). Soil, nutritional and yield data obtained from the trial were further analysed using descriptive and inferential statistics.
: North-Western Free State farmers had a positive perception towards crop diversification, with 87% of them rotating crops, showing movement from crop specialisation towards crop diversification. Rotational systems in the field trial maintained soil health, provided nutritional benefits and improved crop production and productivity. Seasonal variation (mainly rainfall) played a role on soil health, nutrition and crop production, with most aspects being negatively affected by above normal rainfall conditions.
: This study provided insight into the effect of crop rotation specific to the North-Western Free State. The rotational systems investigated were viable, with potential for agricultural sustainability. The study recommends that maize rotational systems incorporating soybean and cover crop be implemented in the area to ensure sufficient and nutritious food, while conserving and improving the soil and environment
Differential expression of microRNAs in drought-stressed sorghum roots
No full textDissertation (M.Sc.(Plant Sciences))--University of the Free State, 2024Sorghum ( ) is an important source of food, fibre, and fuel. While it is a drought-tolerant crop, its yield is still affected by drought stress, threatening food security. Therefore, there is a need to study the drought responses of plants to develop more drought-resilient crops. This study aimed to identify drought-responsive microRNAs in sorghum roots to understand the gene regulatory processes in drought stressed sorghum. ICSB 338 (drought-susceptible) and SA 1441 (drought-tolerant) sorghum seeds were germinated and grown for three weeks with adequate watering. Subsequently, the plants were divided into two groups: A drought-stressed group, where water was withheld for 15 and 28 days to induce mild and moderate drought stress, respectively, and a control group that continued to receive adequate watering. The results showed a significant decrease in pot weight, soil moisture content, and stomatal conductance for both sorghum varieties under drought stress conditions.
The leaf relative water content of ICSB 338, significantly declined following the 15 and 28 days of drought stress treatment compared to the controls. The physiological responses of the two sorghum varieties differed, with ICSB 338 being more affected by drought stress than the SA 1441. The molecular responses of sorghum to drought stress were investigated using small RNA sequencing performed on the watered controls and drought-stressed root samples of both varieties. The MGI DNBSEQ-G400 sequencing technology was used to identify the differentially expressed microRNAs. A total of 81 and 83 constitutively expressed miRNAs were identified in the watered control samples of ICSB 338 and SA 1441, respectively. Among these constitutively expressed miRNAs, 73 were common in both sorghum varieties, while eight and 10 miRNAs were unique to ICSB 338 and SA 1441, respectively. The analysis also revealed that four of the constitutively expressed microRNAs were differentially expressed between ICSB 338 and SA 1441 plants (p ≤ 0.05). The target genes of the constitutively expressed sorghum root microRNAs were predicted using the psRNATarget database, which also revealed that most of the miRNA inhibited their target genes through messenger RNA cleavage. Gene Ontology analysis of the target genes revealed that the constitutively expressed microRNAs regulate a wide range of genes with diverse cellular locations, molecular functions and biological processes in sorghum roots. Drought-responsive microRNAs (p ≤ 0.05) were identified using the CLC Genomics Workbench software (Qiagen) by comparing the watered controls and drought-stressed miRNAs using the Differential Expression for RNA-seq tool. Out of the 111 identified miRNAs in both varieties, only four and nine miRNAs were differentially expressed in ICSB 338 and SA 1441, respectively. miRNAs sbi-miR6233-3p and sbi-miR821a were up-regulated, while sbi-miR5566 and sbi-miR6224a-5p were down-regulated in ICSB 338 sorghum roots.
Bioinformatics analyses predicted a 557200 gene as a potential target for sbi-miR6233-3p, while sbi-miR821a targeted an unknown gene. The targets for sbi-miR5566 and sbi-miR6224a-5p were an 8057912 and 8055016, respectively. For SA 1441, two microRNAs (sbi-miR5564c-5p and sbi-miR6232b-3p) were up-regulated while seven (sbi-miR168, sbi-miR2118-5p, sbi-miR395a, sbi-miR5387b, sbi-miR5568c-3p, sbi-miR6229-5p, sbi-miR6235-5p) were down-regulated. The descriptions of the predicted target genes of SA 1441 included - 83, 3, 10 2.1, 123 , and -3- . Overall, the findings of the current study contribute to our knowledge of the mechanisms sorghum uses to cope with drought stress
Synthesis, electrochemistry, and density functional theory of osmium(II) containing different 2,2′:6′,2″-terpyridines
No full textIn coordination chemistry, 2,2′:6′,2″-terpyridine is a versatile and extensively studied tridentate ligand. Terpyridine forms stable complexes with a variety of metal ions through coordination sites provided by the three nitrogen atoms in its pyridine rings. This paper presents an electrochemical study on various bis(terpyridine)osmium(II) complexes, addressing the absence of a systematic investigation into their redox behavior. Additionally, a computational chemistry analysis was conducted on these complexes, as well as on eight previously studied osmium(II)-bipyridine and -phenanthroline complexes, to expand both the experimental and theoretical understanding. The experimental redox potentials, Hammett constants, and DFT-calculated energies show linear correlations due to the electron-donating or electron-withdrawing nature of the substituents, as described by the Hammett constants. These substituent effects cause shifts to lower or higher redox potentials, respectively.Publisher's versio
Invasive status of pampas grass in South Africa
No full textDissertation (M.Sc.(Botany))--University of the Free State, 2024Two species, . and . have become invasive outside their native range, including in South Africa. They were introduced to South Africa for ornamental use, erosion control and stabilising mine-dumps. They have long escaped containment and spread throughout the country, invading grasslands, roadsides, wastelands, rivers and seasonally wet habitats. Little is known regarding their distribution, seed viability and whether accurate identifications have been made of the species in South Africa, which may hinder effective management. Although the national regulations forbid the trade of pampas grass, the continuing popularity of their inflorescences for home décor and special events is of concern. While nurseries have stopped the sale of the plants, inflorescences are still being sold through retail and informal trade. This study aimed to assess the invasion risk posed by pampas grass in South Africa and distinguish between the different species across their invaded range using molecular techniques. Leaf and seed samples were collected from 79 populations across South Africa.
Eight microsatellite primers were used to assess the genetic variation across a populations. Seed viability and germination success were assessed for seeds from 28 naturalised and 13 traded inflorescences using a triphenyl tetrazolium stain, and germination trials in a growth chamber and greenhouse. Impacts and risks of . and . in South Africa were assessed using version 1.2 Risk Analysis for Alien Taxa (RAAT) framework. Microsatellite confirmed the presence of . and . in South Africa and that . populations have higher genetic diversity compared to from other invaded regions. Tetrazolium tests found that . (71.66 %) had higher seed viability than . (54.28 %). Assessments of germination trials in a growth chamber revealed that . (68.89%) had a higher proportion of seeds germinate compared to . (52.62 %) but this difference was not statistically significant. Seed germination under greenhouse experiments also found . (79.15 %) to have higher germination success compared to . (62.54 %). Seed viability of cultivated and naturalised inflorescences differed significantly to formally traded inflorescences but not significant to informally traded inflorescences. Seeds from naturalised populations of both species had significantly higher germination success (65.69 %, 74.35 %) than the formally (25.00 %, 5.33 %) and informally traded populations (28.75 %, 35.56 %) under growth chamber and greenhouse experiments, respectively. Viability and germination success of seeds from cultivated inflorescences were statistically similar to naturalised inflorescences while those from formally traded inflorescences performed statistically similar to seeds from informally traded inflorescences across triphenyl tetrazolium stain, growth chamber and greenhouse experiments.
The risk analysis assessments determined that both . and . have major impacts and a high risk of invasion in South Africa with medium ease of management. Determining the invasion risk posed by pampas grass in South Africa has provided important information on managing these species. Biological control is species-specific; therefore, this study has provided information that will guide the biological control programme of pampas grass in South Africa and future research can focus on finding potential biocontrol agents. Seed viability and germination experiments established that when seeds are present on flowers, most of them are viable and that traded inflorescences’ seeds are not sterile and can thus be promoting invasion and further spread of species. Effective management of species must focus on enforcing legislation to stop this pathway of spread
Factors influencing access to Real Estate Finance in Bloemfontein
No full text.Dissertation(MBA (Business Administration))--University of the Free State, 2024Accessing real estate finance is crucial for homeownership, yet navigating the complexities of the mortgage lending landscape remains challenging. This qualitative study explores the various factors influencing the success of home loan applications in Bloemfontein, South Africa. Through in-depth interviews with industry experts and a thorough review of existing literature, this research identifies key determinants affecting borrowers’ ability to secure mortgage financing.
The study reveals that borrower-bank relationships play a critical role, with existing clients often receiving preferential rates. However, leveraging mortgage originators can lead to better deals by harnessing competition among multiple banks. Property characteristics, including type and location, significantly influence loan approval and pricing, with banks exercising caution in funding properties in high-risk areas or certain property types. Additionally, borrower education programmes are recognised as vital tools in enhancing financial literacy and empowering prospective homebuyers to make informed decisions throughout the loan application process.
Government-subsidised housing programmes, exemplified by initiatives like the Finance Linked Individual Subsidy Programme (FLISP), hold a promise to increase successful home loan applications. However, challenges in programme implementation and accessibility persist, highlighting the need for continued improvement. Furthermore, the study emphasises the critical role of qualitative research methodology in capturing nuanced insights from industry stakeholders.
Importantly, mortgage originators emerge as significant facilitators in the home loan application process, providing borrowers with access to competitive rates and guiding them through complex lending procedures. This study offers actionable recommendations for stakeholders aiming to enhance access to mortgage loans in Bloemfontein, setting the stage for initiatives focused on promoting financial inclusion and fostering a dynamic real estate market
The impact of global risk aversion and domestic macroeconomic factors on the dynamic conditional correlations of South African financial markets
No full textThis paper considers the impact of global risk aversion and domestic macroeconomic factors on the dynamic conditional correlations between the South African stock, bond, and foreign exchange markets. Our first stage findings using the DCC-GARCH model show that correlations between the selected markets are significantly dynamic over time. We further show that the correlations of asset pairs do not fall for extended periods during crisis periods, implying only short-lived increase in diversification benefits. Further analysis using the OLS regression model shows that global risk aversion and domestic macroeconomic factors have a heterogenous impact on the dynamic correlations of asset pairs. Consequent to these findings, this study advocates for the adoption of dynamic asset allocation and diversification strategies necessitating the periodic optimisation of portfolios as asset correlations, global risk aversion and domestic macroeconomics evolve. The study offers valuable insights and policy recommendations for investment practitioners, policymakers, and academics.Publisher's versio
Breed genetic and heterosis effects on variability of growth and efficiency traits in beef cattle
No full textThesis (Ph.D.(Animal Science))--University of the Free State, 2024The first goal of this investigation was to characterize breed genetic effects for indigenous and exotic breeds of beef cattle under South African conditions. A second goal was to characterize within animal daily variation in partial body weight and feed intake during the postweaning period. It is intended that these characterizations will lead to better choices among breed resources, particularly for emerging farmers. Thus, a crossbreeding trial was conducted in South Africa, Northern Cape, over a period of eight years from 2015 until 2022. Afrikaner, Bonsmara and Nguni dams were mated with Afrikaner, Bonsmara, Nguni, Angus, and Simmentaler sires. Data were collected according to the National Beef Recording and Improvement Scheme in South Africa. There were 212, 324, 303, 179 and 234 calves sired by Afrikaner, Nguni, Bonsmara, Angus and Simmentaler sires, respectively. There were 182, 633 and 437 calves produced by Afrikaner, Nguni and Bonsmara cows, respectively. Birth and 205-day weights were analyzed including effects of year, sex, age of dam, the genetic expectation for breed group, and the interactions of year with the breed direct and maternal effects and individual heterosis. The probability levels (P-values) for the interaction of the genetic effects and year indicate plasticity with respect to the inter-year environment. Plasticity is defined as deviations in an individual’s phenotype in reaction to environmental fluctuations. The P-values for birth weight interactions of Afrikaner, Angus, Nguni and Simmentaler direct effects with year were 0.06, 0.09, 0.01, and < 0.01, respectively. The corresponding P-values for 205-day weight were 0.69, 0.03, 0.15, and 0.10. Thus, birth weight appeared to be more plastic, i.e., more sensitive to the variation among years, than was 205-day weight. The temperature-humidity index during the study period varied between 78.5 and 81.6.
Previous studies indicate that heat stress is induced if temperature humidity index ≥ 72 and thus the preweaning environment was very harsh. After weaning, the male calves were transported from Vaalharts to Irene in groups of 25-28 according to their weight. Upon arrival, the animals were given a 2-week adaptation period and were then allocated to pens in the GrowSafe system according to their body weight. This system of allocation resulted in the partial confounding of breed groups, contemporary groups, and the days on feed. The data were analysed with linear models that included the categorical effects of test group and breed group and the continuous effect of days on test. Breed group effects on daily feed intake and partial body weight were not detected (P > 0.05). As expected, the animals ate more and became heavier as the test progressed (P < 0.05). The breed groups differed in their growth rate as evidenced by the significant interaction between the breed group effect and the linear effect of days on test for partial body weight. However, the rate at which animals increased their daily feed intake was invariant to their genotype. In partitioning the interaction of breed group with days on test into single degree of freedom effects, only the effect of individual heterosis on partial body weight (0.99 ± 0.35 kg/day) was significant (P <0.01).
Adding the binary indicator of heat stress to the linear model indicated highly significant effects on both daily feed intake (-9.69 ± 1.31 g/day) and partial body weight (48.2 ± 2.1 g/day). Animals that were heavier consumed more feed (37.7 ± 4.8 g/day; P <0.01) and animals that consumed more feed were heavier (57.1 ± 9.3 g/kg; P <0.01) as this is expected. Estimates of the serial correlations of daily feed intake and partial body weight were calculated for each animal. These correlations were transformed to z-statistics before being analysed further. Average estimates for the z-transformed serial correlation of daily feed intake and partial body weight for each animal were 0.1003 and 3.0506, respectively. The 95% confidence interval for daily feed intake was 0.095 < z < 0.106; and for partial body weight it was 3.041 < z < 3.061. However, it does not appear these differences are related to the breed composition of the animals. The high degree of between-animal variation in the estimate of the serial correlation indicates animals differ markedly for feed they consume from day-to-day. In contrast, the estimates of serial correlation of partial body weights were very high and consistent across animals.
Thus, there is little need to average values over days to achieve an accurate estimate of partial body weight at any specific point in time. An evaluation of postweaning feed intake that was conducted over a 36-day period would, on average, produce an accuracy of the daily feed intake mean for an individual animal of 0.80. The inter-day variance in feed intake served as a metric for the evaluation of plasticity. These data were analyzed using Friedman’s test based on a non-parametric two-way analysis of variance. The breed groups differ significantly in their plasticity of feed intake. Linear functions of the breed group effects indicated that the Nguni, Simmentaler, Afrikaner, and Angus breed direct effects were more variable over time than was the Bonsmara direct effect. The estimated heterosis effect was small and not significant indicating that crossbred cattle would be no more variable over time in feed intake than their straightbred counterparts. Some commercial producers and probably all subsistence producers might choose a less plastic and more robust set of breed resources, which may perform well, regardless of the current environment. However, resource-rich commercial producers might prefer to utilize more plastic breed resources to capitalize on times when the environment is favorable and mitigate less favorable times
Synthesis of redox-responsive tetrathiafulvalene derivatives with amphiphilic properties to be used in soft materials
No full textDissertation (M.Sc.(Chemistry))--University of the Free State, 2024The well-known electron-rich donor system, Tetrathiafulvalene (TTF) has gained excessive interest in the field of supramolecular chemistry and complex ligand research. Continuous advancements in synthesis has allowed TTF along with its derivatives to be integrated into various intricate molecular systems. Such that, these systems have been investigated for their potential applications as sensors, models for electron transfer, molecular machines and many other applications. The study displayed in this piece of writing will examine the incorporation of TTF moieties through preparation by synthesis, as well as their characterisation. With the motive to add to the recent and existing synthetic advances, for utilization in constructing versatile systems of broad applications.
A series of functionalised bis- and tetra-tetrathiafulvalene derivatives has been prepared. A result stemming from a series of synthesis producing TTF intermediates, later used as key precursors for the successful synthesis of TTF derivatives. Amongst those, is the TTF thiolate anion used as a key intermediate which has shown to be quite a versatile reagent for this purpose. Shelf-stable precursors of the TTF thiolate anion have been prepared, making the preparation of novel, highly functionalised, amphiphilic cationic / anionic TTF derivatives 4 and 5 feasible. The series of steps include various reactions: cyclization, cross coupling and self-coupling, de-protection, re-alkylation, and nucleophilic substitution reactions. This synthetic pathway allows the tailoring of the properties of the TTF entity by the variation of the substitution pattern. For feasibility of the amphiphilic character, the analogues prepared constitute of long alkyl chains at different positions. This character adds in rendering these entities as versatile electron donor systems, well suited for use in construction of novel redox assemblies.
Through careful adjustments and development of methodologies, a range of symmetrical and unsymmetrical TTF derivatives of different substituents was covered. From alkyl-halides bearing TTF derivatives to the 1-methyl-imidazole units fused to the TTF frameworks. Certain compounds were obtained in significantly high yields. Such as the 1-methyl-imidazole bearing TTF derivative, 4,5-bis(1-methylimidazole-3-propylthio)-6,7-bis(propylthio)tetrathiafulvalene 4a at a yield of 94%. With its identity qualitatively confirmed by high-resolution mass spectroscopy and NMR analysis.
In the study, several purification techniques were implemented with the hopes of producing highly pure and well isolated compounds. Some of the reactions produced several products which were difficult to separate. An attempt to conduct electrochemical studies on the new multi-TTF derivatives, was deemed unsuccessful for various reasons covered in the discussion