University of the Free State
  • Bloemfontein, Free State, South Africa
Recent publications
Unconventional oil and gas (UOG) extraction can augment energy supplies in countries with viable gas resources, but it risks damaging water resources. Water supply problems for fracking can also limit UOG extraction, especially in water-stressed regions. Regulations are one of the main tools used to minimize UOG extraction impacts on water resources. Many states in the US and Canada have extensive regulations to protect water resources during UOG extraction but they are often ineffective, either because they were poorly drafted or because they are not properly enforced. South Africa is a water-scarce, groundwater-dependent country that is considering UOG extraction in the future. South African groundwater experts were surveyed on what regulations are needed to protect groundwater resources and how to enforce them. This study recommends specific UOG extraction regulations to protect groundwater resources, which are not only relevant to South Africa, but also to other countries that extract UOG resources.
Indigenous leafy vegetables (ILVs) do not only play a significant role in ensuring livelihoods for households in South Africa but can also contribute in enhancing the consumption of diversified foods for improved micronutrient intake. However, these plants are underutilized and their consumption is determined by ILVs' regional cuisines accepted in certain ethnic groups. This study was set out to assess the acceptance of indigenous leafy vegetables by consumers in Limpopo and Mpumalanga provinces. The study used secondary data that were collected by the South African Vulnerability Assessment Committee in 2016. A total of 1520 respondents were selected from the two provinces using a multistage stratified sampling method. The results of the descriptive statistics showed that blackjack was the least consumed leafy vegetable as compared to amaranth and cleome, which were, respectively, most consumed. Seemingly unrelated regression (SUR) model was employed to analyse the determinants of consumers’ acceptance of ILVs. The results of SUR showed that gender of the household head, marital status, HIV status, wages/salary, and grants were statistically significant in influencing the acceptance of ILVs by consumers. Education and marital status had a negative influence on the acceptance of all leafy vegetables being investigated in this study. Policy makers need to consider the inclusion of ILVs into the school curriculum and national food and nutrition security policy.
Background Cardiopulmonary resuscitation (CPR) improves immediate survival and survival to discharge in patients with cardiac arrest in hospital. Without frequent retraining in CPR, healthcare providers may lose their skills and knowledge earlier than the recommendation of CPR retraining every two years. Objectives To determine the competencies of doctors at an academic hospital regarding CPR training, knowledge, experience and perceptions. Methods A custom-designed questionnaire reviewed by CPR providers was distributed to doctors to obtain information on CPR training, exposure to and perceptions of CPR retraining, and CPR knowledge. The knowledge component of the questionnaire comprised questions on basic, advanced cardiac, paediatric, neonatal and obstetric life support. Results Of the 245 participants, 22.5% achieved competency (a mark of ≥ 80%) for the knowledge component of the questionnaire. The majority of participants had not undertaken retraining after two years, although 96.7% of participants felt that keeping up-to-date with CPR guidelines would improve patient outcomes. The most common reasons provided for not feeling confident in performing CPR were related to training. Conclusion Doctors at the academic hospital in this study are currently not adequately trained in CPR, which is reflected by their lack of CPR knowledge. Lack of training seems to be the most common reason for not feeling confident, and being too busy to attend these retraining courses was reported as the most common reason. It further seems that very few of the departments have CPR training for their doctors. A regular in-hospital CPR training program may improve doctor's CPR knowledge.
Defect-complexes are point defects that significantly influence the geometric, optical, and electrical properties of materials. Defect-complexes are known to improve the electronic and electrical properties of Ge. Deep and shallow defect levels in Ge have been linked to defect-complexes formed by the double self-interstitials and rare earth atoms. Despite this breakthrough, several defect-complexes in Ge are not well understood; hence may pose as a challenge to the optimal performance of Ge based devices. In this study, we present the results of the hybrid density functional theory calculations of substitutional and interstitial defect-complexes (BGeNi, NGeBi, AlGePi, PGeAli, GaGeAsi, AsGeGai, InGeSbi, and SbGeIni) in Ge. Their formation energies, electronic properties, defect-complex stability and induced defect levels in Ge were predicted. While the formation energies of the defect-complexes formed by the P and Al atoms were relatively low and energetically more favourable, those defect-complexes formed by the B and N atoms were the least energetically favourable. Except for the BGeNi, all the defect-complexes significantly bound with energies lower than their formation energies. The NGeBi and PGeAli essential donor levels were in the band gap of Ge. A shallow double acceptor defect level was found to be associated with the AlGePi, while the InGeSbi induced a shallow double donor defect level. The electrical inactive defect-complexes were the BGeNi, GaGeAsi, AsGeGai and SbGeIni. The results of this report are important, as they provide theoretical insight of the prediction of the n/p-type substitutional and interstitial defect-complexes in Ge.
Berberis julianae commonly known as Wintergreen barberry or Chinese barberry, is an evergreen shrub species native to China which has been introduced into South Africa and has become invasive in a few locations. In 2015, management measures were taken in an attempt a control a population in Golden Gate Highlands National Park (GGHNP) in the Free State Province. After assessing the plant demographics within the park, the following management options were implemented: cut stump treatments of larger shrubs, foliar spray herbicide applications and hand pulling of seedlings. It was recommended that follow-up research be conducted to check if control measures were successful or not. This study aimed to map and determine the current distribution of B. julianae in GGHNP and to investigate the change in B. julianae population demographics to that recorded previously. The study showed that the number of seedlings had multiplied from 6 seedlings in 2014 to 588 in 2020, whereas the number of mature shrubs had decreased in the same time period. In conclusion, the control measures conducted have been successful in reducing the adult population, however, additional follow-up control of seedlings is urgently required to stop further spread.
This paper discusses post-apartheid planning reform in South Africa and identifies the successes and failures thereof, as understood by South African planners. We noted a perception of success regarding the reform of planning legislation; however, the general feeling was that planning had failed to achieve spatial transformation in the post-apartheid era. A variety of reasons were given for this: the failure to achieve reservation of planning work for planners, political interference, weak planning tools, lack of capacity, and planners' lack of key skills. We argue that underlying these failures was a deeper issue, namely that many powerful stakeholders in the built environment seemingly did not ascribe value to the planning process. In other instances, they may accept the value of the process, but not the uniqueness of planners' skills. This divergence of opinion of and power struggle between the legitimacy of planning versus planners shapes both the form that planning reform takes, but also the perceptions of the successes or failures of planning reform. Consequentially, this means that to achieve ‘successful’ planning reform, it is necessary to account for how the interaction of micro (individual) and macro-meso (organisational, societal) agendas shape these processes.
Soil classification is based on both the properties of the soil material and the pedogenetic pathways responsible for those properties. Because soil properties are linked to soil function and potential, information on soil classification has formed the basis for empirical interpretations of mapping units in terms of limitations or suitabilities for a wide range of land uses. In this way, a soil type acts as an accessible “carrier of information” presenting “the story of..”. Though valuable for broad land-use assessments, these empirical interpretations of soil functionality are inadequate to answer modern interdisciplinary questions focused on sustainable development. Four case studies are presented showing various quantitative approaches focusing on soil functions contributing to ecosystem services in line with the United Nations Sustainable Development Goals (SDGs) and the European Green Deal, demonstrating that: (i) the use of soil surveys and associated databases feeding soil–water-atmosphere-plant simulation models can contribute to defining soil functions and ecosystem services; (ii) hydropedological characterization of soil types can allow a strong reduction in the number of landscape units to be considered, improving practical applicability; (iii) pedotransfer functions can successfully link soil data to modeling parameters; (iv) functionality requires expression of soil management effects on properties of a given soil type, to be expressed by phenoforms; (v) only models can be applied to explore important future effects of climate change by running IPCC scenarios; and (vi) the most effective level of soil classification—acting as carriers of information when defining soil functionality—will differ depending on the spatial scale being considered, whether local, regional or higher.
Study region South Africa. Study focus This study focuses on the impact of overgrazing on the water resources in a semi-arid catchment in South Africa. We have applied the SWAT+ model to a data-scarce area. During the modeling process, hydropedological principles were applied in model parameterization and analysis of simulation results to identify areas which are sensitive to overgrazing. The scenario analysis indicates that overgrazing might not necessarily have a large impact on the water balance of the whole watershed, but may have negative impacts at the local subbasin scale. These impacts are increased surface runoff and evaporation which are the consequence of compaction of topsoils. New hydrological insights for the region The application of hydropedological principles in the analysis of simulation results help to identify areas sensitive to overgrazing. Shallow soils, soils with low surface infiltration capacities and hydromorphic soils are vulnerable to adverse effects from overgrazing.
Black nanosilver–doped titanium dioxide (Ag-TiO2) nanoparticles (NPs) were prepared for the first time using the modified sol–gel technique. TiO2 is a suitable nanomaterial for photocatalytic degradation of water pollutants due to the hydroxyl radical. The modified sol–gel method was employed due to its ease of operation, cheap, versatile, and better morphology. The physical, optoelectronic, morphology, and photocatalytic properties were investigated. The powder X-ray diffraction (XRD) results confirmed the presence of the anatase phase in all the samples. Ultraviolet–visible spectroscopy (UV–vis) spectra showed that the band gap narrowing caused by Ag doping increased photocatalytic operation in the visible-light region significantly. Scanning electron microscopy (SEM) results revealed that the particles were spherical-like in shape while energy dispersive spectroscopy (EDS) analysis confirmed the presence of the anticipated elements. The functional groups of the samples were identified using Fourier-transform infrared (FTIR) spectroscopy. Photoluminescence (PL) results indicated that the peak intensities decreased with an increase in the amount of dopant. The sample obtained at 3.2 mol % of Ag exhibited the highest photoactivity during the oxidation of the brilliant green dye (BG). The study provides a simple route to synthesize a single anatase phase for photoactivity and advances its enhanced properties.
A hybrid preventive maintenance policy for heterogeneous degrading items is discussed. It combines the classical age-replacement strategy, when a system is replaced either on failure or at the predetermined age, with replacement of the system when degradation reaches the predetermined level at some intermediate time. Items come from two subpopulations with different reliability characteristics. Non-homogeneous gamma processes model degradation of an item from each subpopulation. We justify probabilistically the superiority of the proposed policy over that for homogeneous populations and over the policy without possibility of additional replacement. The corresponding long-run cost rate is derived for the suggested cost structure. Some detailed numerical illustrations are presented and relevant sensitivity analysis for the main parameters of the model is performed.
One of the widely discussed in the literature and relevant in practice shock models is the delta-shock model that is described by the constant time of a system’s recovery after a shock. However, in practice, as time progresses and due to deterioration of a system, this recovery time is gradually increasing. This important phenomenon was not discussed in the literature so far. Therefore, in this paper, we are considering a time-dependent delta-shock model, i.e., the recovery time becomes an increasing function of time. Moreover, we assume that shocks occur according to the generalized Pólya process that contains the homogeneous Poisson process, the non-homogeneous Poisson process and the Pólya process as particular cases. For the defined survival model, we derive the corresponding survival function and the mean lifetime and study the related optimal replacement policy along with some relevant stochastic properties.
There is a need for better financial advice. Financial advisors are not able to give accurate financial advice if clients are not completely truthful. This paper aims to analyse the perceptions of financial advisors regarding client truthfulness when disclosing sensitive financial information. Providing sensitive information, for example income, expenses, level of debt, and medical information, could create feelings of discomfort or embarrassment for both the financial advisor and client. A total of 364 useable questionnaires were returned via an online link sent through a community network email to all members of the industry standard-setting organisation in South Africa. Financial advisors perceive their clients to be more untruthful about sensitive topics such as debt, expenses, and knowledge about their finances. Debt, medical history, and their knowledge about their finances were found to be indicators of embarrassment. The financial advisors indicated their optimism regarding clients' untruthfulness, which is that they need time to build the trust relationship and will subsequently open up. This specific result suggests that the advisors are open to building long-term relationships with clients that can last several years.
Rock glaciers are active sediment transport systems of high mountain periglacial environments. Driven by the internal deformation of their frozen core, they can convey substantial amounts of debris from their nourishing zone towards their front. Depending on the topographic conditions at the front slope, the released sediment is either overridden again by the advancing rock glacier or transferred downwards by rapid mass movements. The capacity of rock glacier environments to transfer sediment however has remained largely unexplored, in particular beyond the local scale. In this work, we consider a rock glaciers’ sediment transfer capacity as a function of its transported volume rate and the travel range of mobilized material at its front. A GIS-based method, low in data-demand, is proposed to generate catchment-scale proxies for the above-mentioned input variables and to combine them to a qualitative index describing sediment transfer capacity of rock glacier fronts. The proposed method is applied in two basins, strongly characterized by periglacial dynamics (Ultental and Schnalstal in South Tyrol, Eastern Italian Alps). In a final step, computed sediment transfer classes are assessed on their geomorphological plausibility by building empirical relationships with independent environmental variables.
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Johan Nel
  • Department of Obstetrics and Gynaecology
Riaz Seedat
  • Department of Otorhinolaryngology
Laurinda Steyn
  • Department of Microbial, Biochemical and Food Biotechnology
Asis Bala
  • Department of Pharmacology
Abhay Mishra
  • Department of Pharmacology
Nelson Mandela Drive 250, ZA-9300, Bloemfontein, Free State, South Africa
Head of institution
Prof Francis Peterson
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