Scielo RSS <![CDATA[South African Journal of Science]]> vol. 118 num. 3-4 lang. es <![CDATA[SciELO Logo]]> <![CDATA[<b>Our Journal in 2021: The year that was</b>]]> <![CDATA[<b>Negotiating with the past by negotiating in the present: A review of <i>Prisoners of the Past</i></b>]]> <![CDATA[<b>Changing long-term care realities and futures for older persons in (West) Africa</b>]]> <![CDATA[<b>A new revision of <i>Agapanthus</i></b>]]> <![CDATA[<b>Elevating everyday learning to a level of awareness where it can make a difference</b>]]> <![CDATA[<b>Energy impoverishment and burns: The case for an expedited, safe and inclusive energy transition in South Africa</b>]]> SIGNIFICANCE: Energy poverty is the constrained access to modern forms of energy. In South Africa, energy impoverished communities are dependent on a mixture of solid fuels (e.g. wood or coal) and hydrocarbons such as paraffin. These, especially paraffin use, are associated with significant negative health outcomes, particularly burns due to accidental fires and spillages, but also paraffin ingestion, and toxic fume inhalation. The energy-poor furthermore suffer disproportionate long-term social, economic and psychological impacts that entrench their impoverished conditions. There is both international and national recognition of these adverse effects of energy poverty and that the universal access to safe and sustainable energy is crucial for the attainment of health and other global social, economic and well-being goals. South Africa is called on to expedite access to modern energy usage, through the enactment of a substantive policy on the provision of safe, clean and affordable energy for energy-impoverished communities and households. <![CDATA[<b>Marine seismic surveys for hydrocarbon exploration: What's at stake?</b>]]> SIGNIFICANCE: We argue that the immediate, intermediate, and long-term implications of seismic surveys for hydrocarbon exploration merit noting. If seismic surveys detect feasible hydrocarbon deposits, they effectively serve as a precursor to hydrocarbon extraction and consumption. The additional greenhouse gas emissions that will originate from new oil and gas fields in South Africa will push the world closer to the tipping point of breaching the limit of 1.5 °C targeted at the 2021 COP26 UN climate summit, and should thus be avoided at all costs. South Africa's pursuit of energy self-sufficiency through local fossil fuel extraction should not come at the cost of its unique biodiversity nor planetary health. <![CDATA[<b>Research and the meaning of 'public interest' in POPIA</b>]]> SIGNIFICANCE: 'Public interest' is an important concept in POPIA. However, the way in which it has been interpreted by the Information Regulator is subject to criticism. A better interpretation is suggested. <![CDATA[<b>Why research institutions should indemnify researchers against POPIA civil liability</b>]]> SIGNIFICANCE: In the research context, a 'responsible party' as contemplated in terms of POPIA is typically the research institution as well as the individual researcher involved. Given the potential civil liability that individual researchers could face, we suggest that the Code of Conduct for Research should place a duty on research institutions to indemnify their researchers from civil liability. While this measure will limit individual researchers' personal financial risk in the extra-institutional legal sphere, it will in no way shield individual researchers from intra-institutional accountability and disciplinary action. Accordingly, we suggest that this measure strikes a fair balance. <![CDATA[<b>What we say and what we do: The perils of ethical consensus</b>]]> SIGNIFICANCE: A new book argues that South Africa could better fight poverty and inequality if the country recognised that caring for others is a duty. It is argued here that the problem is not that we do not all agree on the need for care - it is that we disagree on what that means. A more equal country is possible, not if we all claim to support the same principles, but if we acknowledge our differences and seek compromises between them. <![CDATA[<b>Rusty gold in Nigeria: Untapped advances in nanotechnology</b>]]> SIGNIFICANCE: Reasons for the slow pace of nanotechnology research in Nigeria, Africa's most populous country, are explored, given Nigeria's huge human and natural endowments, and solutions are proffered to address the seemingly lagging outlook of the country in nanotechnology. This Commentary is relevant to all critical stakeholders at national, regional and international levels to mobilise efforts to advance the course of nanotechnology in Nigeria and beyond. <![CDATA[<b>Research contract relationship between a large industry partner and South African universities</b>]]> We propose and evaluate a contractual structuring instrument (in the form of a Framework Research Agreement) in support of research collaboration partnerships between universities and large industry, specifically for the case of large industry in the South African context. This study includes one large South African originated industry (as the pioneer of concluding Framework Research Agreements with several universities) and multiple South African universities, and stretches over several decades. This study was done within the broader context of the challenges and benefits experienced by both industry and university in the academic engagement sphere of industry-university collaboration. By providing insight from both industry and university perspectives, factors impacting on academic engagement (with specific emphasis on the legislative framework, contractual aspects, institutional research contract practices and institutional risks), are considered and discussed. Recommendations are made for improved industry-university collaboration by sharing experiences from the industry and universities on challenges faced, managing the expectations and proposing mechanisms to support constructive research collaboration through a mutually beneficial contractual framework instrument. SIGNIFICANCE: • A novel Framework Research Agreement as a contractual instrument was developed and pioneered by the industry partner with several South African universities, to create a transparent framework based on fair contracting and determinable remuneration principles. • This study specifically highlights the need for a contractual instrument, in which the intention is to build a long-term contractual relationship to support industry-university collaboration and academic engagement within the existing South African legislative framework. • It further draws attention to research contract management practices and contractual aspects, which until now have been largely ignored in industry-university collaboration and academic engagement frameworks of this kind. <![CDATA[<b>Determining safe retirement withdrawal rates using forward-looking distributions</b>]]> An important topic for retirees is determining how much they can safely withdraw from their retirement savings: draw too much from their retirement fund and risk outliving their retirement savings, or draw too little and live below their means. For retirees to decide on the appropriate withdrawal rate, retirees need to have the tools available to decide on their spending rates. There are many factors that influence withdrawal rates, such as initial wealth, asset allocations, age, life expectancy, and risk tolerances. The topic of safe withdrawal rates aims to optimise spending rates while minimising the risk of running out of retirement savings. The focus of this study was on using forward-looking moments of the risk-neutral and real-world asset distributions in determining safe withdrawal rates for South African retirees. The use of forward-looking information, typically derived from traded derivative securities (rather than historical data), is essential in optimising safe withdrawal rates for retirees. In particular, we extracted the forward-looking risk-neutral and real-world distributions from option prices on the South African Top 40 index, and used the moments of the distributions as a signal in a simple tactical asset allocation framework. That is, when we expect the growth asset to decrease in value, we hold cash (or short the asset) and, alternatively, when we expect the growth asset to increase in value, we hold the growth asset for the period. Using this approach, we found that we can sustain withdrawal rates of up to 7% compared to the commonly quoted 4% safe withdrawal rate obtained by historical simulations. SIGNIFICANCE: • Through this paper, we aim to create further awareness on safe retirement spending rates. It is important that retirees are guided through this process with the correct knowledge of the risk and return of asset classes. • Using forward-looking information allows for a more realistic modelling of portfolio returns, which allows for the possibility of better modelling of safe withdrawal rates. • We show that using the moments of the forward-looking distributions in a simple tactical asset allocation framework yielded superior portfolio returns to a fixed asset allocation structure. <![CDATA[<b>Malaria risk and receptivity: Continuing development of insecticide resistance in the major malaria vector <i>Anopheles arabiensis </i>in northern KwaZulu-Natal, South Africa</b>]]> Malaria incidence in South Africa is highest in the three endemic provinces: KwaZulu-Natal, Mpumalanga and Limpopo. The contribution to malaria transmission by several mosquito species, variation in their resting behaviours and low levels of insecticide resistance makes it necessary to periodically monitor Anopheles species assemblages and resistance phenotypes in vector populations. The aim of this study was therefore to assess Anopheles species assemblage in northern KwaZulu-Natal and to collect insecticide susceptibility data for An. arabiensis, the primary vector of malaria in that province. Anopheles specimens were collected from Mamfene, Jozini, northern KwaZulu-Natal from November 2019 to April 2021. Progeny of wild-collected An. arabiensis females were used for standard insecticide susceptibility tests and synergist bioassays. Anopheles arabiensis contributed 85.6% (n=11 062) of the total catches. Samples for subsequent insecticide susceptibility bioassays were selected from 212 An. arabiensis families. These showed low-level resistance to DDT, permethrin, deltamethrin, and bendiocarb, as well as full susceptibility to pirimiphos-methyl. Synergist bioassays using piperonyl butoxide and triphenyl phosphate suggest oxygenase-based pyrethroid and esterase-mediated sequestration of bendiocarb. These low levels of resistance are unlikely to be operationally significant at present. It is concluded that northern KwaZulu-Natal Province remains receptive to malaria transmission despite ongoing control and elimination interventions. This is due to the perennial presence of the major vector An. arabiensis and other secondary vector species. The continued detection of low-frequency insecticide resistance phenotypes in An. arabiensis is cause for concern and requires periodic monitoring for changes in resistance frequency and intensity. SIGNIFICANCE: • Insecticide resistance in the major malaria vector Anopheles arabiensis in northern KwaZulu-Natal Province is cause for concern in terms of resistance management and ongoing vector control leading toward malaria elimination. • Despite ongoing control interventions, northern KwaZulu-Natal remains receptive to malaria owing to the perennial presence of several Anopheles vector species. <![CDATA[<b>Impact of land-use changes on ant communities and the retention of ecosystem services in Rashad District, Southern Kordofan, Sudan</b>]]> The ecological consequences of biodiversity loss are usually the reduction of ecosystem functions. These responses, however, differ depending on the type of land-use change and the ecological setting. We investigated the impact of land-use type and ecosystem functions on the ant assemblage of Rashad District, Sudan. We analysed the effects of three different land uses (soy monoculture, pasture and organic production of vegetables) on the ant community by assessing ant composition in 176 different locations. The collection sites were conventional soy monoculture, pastures, organic agriculture, and native vegetation such as Campo, Kubos, and forests. We recorded 264 ant species on the soil surface of the Rashad District, where 342 to 354 species were thought to exist. Pastures and organic agriculture areas have 61% and 56% of the native myrmecofauna, respectively, while conventional soy monoculture areas are home to only 17% of native ant species. Forest areas present a unique community, and soy monoculture areas have the strongest pattern of biotic homogenisation. We also detected that rare species (of low frequency) were the chief promoters of richness in the Rashad District, and the most threatened with local extinction, due to their low density and low occurrence in agrosystems. Overall, we found that agricultural expansion reduces ant diversity, particularly in soybean crops, and can affect ecosystem functions. To mitigate the reduction in the ant assemblage, we recommend the conservation of multiple natural habitats. SIGNIFICANCE: • Agricultural land conversion and climate change play a major role in shaping tropical landscapes, but the direct and indirect links to biodiversity and species community composition remain poorly understood. • Ant richness is correlated with biomass, demonstrating that the effects on ecosystem function are dependent on the particularities of each assessed function (such as resource type), the types of land uses, and the abundance of ants in the region. • Land-use effects on ant diversity were strongly scale dependent. • The highest ant diversity occurred in soy monoculture areas. <![CDATA[<b>Towards medicinal tea from untapped Namibian <i>Ganoderma: </i>Phenolics and in vitro antioxidant activity of wild and cultivated mushrooms</b>]]> Ganoderma is a genus of mushrooms that is prized in developed nations, especially those in Asia, due to its health-promoting properties, which are attributed to bioactive compounds such as phenolics. However, in developing countries, particularly in Africa, Ganoderma mushrooms are untapped and are barely identified. In this study, we identified Ganoderma species collected from different host trees in the wild in Namibia, cultivated them on one substrate and determined their water absorption and solubility indices. Total phenolics (TP), total flavonoids (TF), condensed tannins (CT) and in vitro antioxidant activity (AA) were determined in hot water infusions made from wild and cultivated Ganoderma mushrooms. Folin-Ciocalteu, aluminium chloride, vanillin-HCl, and DRRH assay methods were used to determine TR TF, CT and AA, respectively. Wild species had 6.12-11.70% moisture, 1.91-5.32% ash, 11.55-24.40 (g of absorbed water/g of dry sample) water absorption index, 3.60-24.10% water solubility index, 18.37-44.78 (mg GAE/g of sample) TR 0.09-1.67 (mg QE/g of sample) TF, 2.97-6.37 (mg CAE/g of sample) CT and 40.8-49.3% AA. Cultivated species had 9.64-13.45% moisture, 2.34-6.20% ash, 13.55-28.30 water absorption index, 6.40-25.35% water solubility index, 36.70-52.73 (mg GAE/g of sample) TR 0.41-0.86 (mg QE/g of sample) TF, 11.38-15.29 (mg CAE/g of sample) CT and 53.6-63.7% AA. Infusions prepared from cultivated Ganoderma species had higher levels of TR CT and AA, but lower levels of TF than those prepared from wild Ganoderma species, suggesting that they have potential as nutraceuticals. SIGNIFICANCE: • The identification and confirmation of highly prized Lingzhi 'mushrooms of immortality' in Namibia highlights the presence of this untapped resource in Africa that is potentially worth billions of dollars. • The cultivation and phenolic content of this high-value medicinal mushroom have been demonstrated. • Cultivation could lead to sustainable utilisation and employment creation in developing countries which suffer from unemployment rates of at least 30%. <![CDATA[<b>Antioxidant activity of the bioactive compounds from the edible fruits and leaves of <i>Ficus sur </i>Forssk. (Moraceae)</b>]]> Ficus sur Forssk. (Moraceae) is a medicinal plant species found in Africa and the leaves are used in traditional medicine as a blood builder to boost iron levels for the treatment of anaemia, skin disorders and sexually transmitted diseases. In this study, a phytochemical investigation was conducted on F sur and the antioxidant properties of the isolates and extracts were evaluated. The major secondary metabolites that were isolated from the fruits and leaves were the triterpenoid (lupeol), sterol (β-sitosterol), phaeophytin (phaeophytin a) and flavonoid (epicatechin). The findings reveal significantly higher (p<0.05) antioxidant activity for the methanol extract of the fruits (IC50 9.06 pg/mL), which may be attributed to the higher phenolic content and presence of epicatechin. The results show the species to be rich in pharmacologically active compounds that are documented to exhibit haematinic effects, stimulate reconstruction and cell proliferation in skin, and inhibit the growth and proliferation of pathogenic agents of sexually transmitted infections. This study therefore validates the ethnomedicinal use of the plant, and its consumption could have a profound influence on nutrition and health, especially amongst indigenous people of Africa. SIGNIFICANCE: • In South Africa, the use of indigenous plants for food and medicine, especially by rural populations, has increased due to availability and accessibility. • This study highlights the benefits of the edible fruits of Ficus sur as a nutraceutical. • Ficus sur is shown to contain biomolecules with well-known therapeutic value, which lends scientific credence and validity to its ethnomedicinal use. <![CDATA[<b>Tiger nut <i>(Cyperus esculentus): </i>Nutrient profiling using HPLC and UV-spectroscopic techniques</b>]]> Food insecurity and undernourishment constitute a major challenge in Africa and the world at large. To meet key nutritional targets and tackle the menace of undernourishment, we need to exploit available but underutilised food crops. A common underutilised food crop with the potential to improve daily nutrition is tiger nut. This potential is evidenced in the number of essential amino acids detected, which constitute 74.425% of the entire amino acids detected, in addition to important minerals and vitamins. The nutritional composition of the yellow variety of tiger nut (Cyperus esculentus) was determined using the standard methods of high-performance liquid chromatography and UV-spectroscopy. Ten amino acids were identified and quantified, including six essential amino acids, of which valine had the highest concentration (67.59 μg/100 g), followed by leucine (3.019 μg/100 g), phenylalanine (1.767 μg/100 g), lysine (0.946 μg/100 g), histidine (1.048 μg/100 g) and tryptophan (0.055 μg/100 g). The other amino acids were proline (24.124 μg/100 g), cysteine (1.269 μg/100 g), glycine (0.024 μg/100 g), and glutamine (0.022 μg/100 g). Monosaccharides detected were ribose (41.76%), glucose (21.52%), sedoheptulose (17.94%), fructose (4.566%), rhamnose (1.78%) and mannose (1.58%), whilst disaccharides detected were sucrose (87.66%) and maltose (11.39%). Mineral concentrations were K 144.80 ± 1.10 mg/100 g, Ca 94.39 ± 0.02 mg/100 g, Na 83.92 ± 0.04 mg/100 g, Fe 19.36 ± 0.54 mg/100 g, Mg 17.63±0.13 mg/100 g, Cu 13.28±0.05 mg/100 g and Zn 5.18±0.01 mg/100 g Vitamins A, B2, C and E were detected and quantified as 53.93±1.03, 7.61±1.20, 31.70±1.25 and 128.75±0.74 μg/100 g, respectively. The chemical and nutritional properties of the yellow variety of tiger nut suggest that it is rich in essential amino acids, minerals, and some vitamins. Hence, it should be recommended to persons with nutritional deficiencies as it is cheap and available all year round. SIGNIFICANCE: • The nutritional composition of the yellow tiger nut will assist in meeting the recommended daily intake of essential amino acids, monosaccharides, disaccharides, minerals, and vitamins, thus contributing towards solving the challenge of food insecurity and malnutrition, particularly in the African sub-region. • The rich concentration of these nutrients could be harnessed in the biofortification of food materials known to be deficient in one nutrient or another. • These important attributes of tiger nut, if harnessed, will add value to this underutilised crop and enhance the economic livelihood of the local farmers. <![CDATA[<b>Effects of browse legume species addition on nutritional composition, fermentation characteristics and aerobic stability of <i>Opuntia </i>cladodes silage</b>]]> Forage legumes are commonly used as an absorbent additive in high-moisture silages. Thus this study was carried out to assess the nutritive value, fermentation characteristics and aerobic stability of Opuntia-legume browse mixed silages. Five browse legume species (Leucaena leucocephala, Acacia mellifera, Searsia lancea, Prosopis velutina, and Grewia flava) were mixed with Opuntia cladodes. The silage mixture was formulated at a ratio of 60 Opuntia cladodes: 40 leguminous browse species and ensiled in polythene bags and kept in a laboratory for 42 days to determine chemical composition and fermentation characteristics. Silage samples were also subjected to an aerobic stability test. One-way analysis of variance in a completely randomised design was used to analyse the data. The pH values for silages made from Opuntia cladodes with L. leucocephala, A. mellifera and G. flava were lower than 4.8, which is considered an indicator of good-quality silage. The water-soluble carbohydrates content of silages made with Opuntia cladodes and S. lancea and G. flava was within the range of 8-12 g/kg dry matter, which is sufficient for good fermentation. The highest CO2 production, which signifies poor aerobic stability, was recorded for the control silage (Opuntia) compared to all Opuntia-legume mixed silage treatments. The addition of legume browse leaf-meal to Opuntia cladodes improved nutritive value, fermentation characteristics, and silage quality. Therefore, despite some limitations, Opuntia-legume browse silages, particularly Opuntia-G. flava and Opuntia-L. leucocephala, proved to be beneficial for livestock, as they meet the nutritional requirement of a ruminant. SIGNIFICANCE: This study underlines the importance of co-ensiling Opuntia cladodes and high protein legume browse hay to offer an alternative feeding strategy for ruminant livestock and ensure sustainable provision of high-quality feed during dry periods. <![CDATA[<b>Isotopic profiling of natural uranium mined from northern Nigeria for nuclear forensic application</b>]]> Four mined samples of natural uranium from northern Nigeria were studied through inductively coupled plasma mass spectrometry, at the Environmental Analytical Chemistry Laboratory, University of the Witwatersrand, Johannesburg. The samples were characterised for lead, thorium and uranium isotopic concentrations, isotopic ratios and age. The objective was to obtain nuclear forensic fingerprints as baseline data to add to the Nigerian National Nuclear Forensic Library. Results showed significant variation in the isotopic concentrations of lead, thorium and uranium across the mines. lsotopic ratios of 238u/235u, 235u/238u and 234U/238U across the sample of 137.881±0.007, 7.253x10-03±2.05x10-04 and 5.540x10(05)±4.08x10-07 were found to be consistent with the natural values. The age of natural uranium is comparable to the age of earth. Uranium, lead, and thorium isotopic concentrations and ratios, as well as the age of the samples characterised, provide an isotopic profile that can be used for nuclear forensic application. Significance: • Given the abundant deposits of natural uranium in Africa and the consequent potential for nuclear insecurity, determining the isotopic profiles and signatures of natural uranium is important for application in nuclear forensics. • Isotopic concentrations of 232Th, 238U, 235U and 234U from the respective sampling sites differed significantly, thereby providing characteristic isotopic profiles. <![CDATA[<b>Shape analysis of the StW 578 calotte from Jacovec Cavern, Gauteng (South Africa)</b>]]> The fossiliferous deposits within the lower-lying Jacovec Cavern in the locality of Sterkfontein yielded valuable hominin remains, including the StW 578 specimen. Because StW 578 mainly preserves the calotte, the taxonomic status of this specimen has been a matter of discussion. Within this context, here we employed high-resolution microtomography and a landmark-free registration method to explore taxonomically diagnostic features in the external surface of the StW 578 calotte. Our comparative sample included adult humans and common chimpanzees as well as one Australopithecus africanus specimen (Sts 5). We partially restored the StW 578 calotte digitally and compared it to extant specimens and Sts 5 using a landmark-free registration based on smooth and invertible surface deformation. Our comparative shape analysis reveals morphological differences with extant humans, especially in the frontal bones, and with extant chimpanzees, as well as intriguing specificities in the morphology of the StW 578 parietal bones. Lastly, our study suggests morphological proximity between StW 578 and Sts 5. Given the intimate relationship between the brain and the braincase, as well as the integration of the hominin face and neurocranium, we suggest that cranial vault shape differences between StW 578 and extant humans, if confirmed by further analyses, could be either explained by differences in brain surface morphology or in the face. Besides providing additional information about the morphology of the Jacovec calotte that will be useful in future taxonomic discussion, this study introduces a new protocol for the landmark-free analysis of fossil hominin cranial shape. SIGNIFICANCE: • We provide further information on the enigmatic fossil specimen StW 578. • We introduce a new approach for the morphological study of fossil hominin crania. • We highlight morphological similarities between StW 578 and 'Mrs Ples'. <![CDATA[<b>Mandibular ramus morphology and species identification in <i>Australopithecus sediba</i></b>]]> The site of Malapa, South Africa, has produced fossil evidence from multiple individuals of Australopithecus sediba including the partial skeletons designated as MH1 (holotype) and MH2 (paratype). A recent article in this Journal presented the hypothesis that MH1 and MH2 are not one species but instead represent two different genera: Australopithecus and Homo, respectively. Here we briefly evaluate this claim. We review the evidence from across the skeleton that demonstrates that MH1 and MH2 represent a single species, and we highlight other fossil samples that show the same pattern of mandibular ramus variation as observed in MH1 and MH2. The evidence shows that there is no reason to separate MH1 and MH2 into different species or genera based upon mandibular ramus morphology. This case illustrates how misleading small fragments of anatomy can be, why researchers should not use such fragments particularly for species and genus-level diagnoses, and why it is essential to use all available evidence. SIGNIFICANCE: This study shows that the mandibular variation that is present in fossils from Malapa attributed to Australopithecus sediba has parallels in both Australopithecus africanus and in Homo. This helps to demonstrate that mandibular form is not sufficient to provide evidence of species diagnosis, but also that the development and adaptations to diet in Au. sediba were overlapping with those present in other related species of hominins. <![CDATA[<b>Morphological variation in the distal phalanges of the springbok, <i>Antidorcas marsupialis </i>(Zimmermann, 1780) (Mammalia: Bovidae)</b>]]> A comparative study of distal phalanges belonging to adult springbok individuals shows distinctive morphological differences between the subspecies Antidorcas marsupialis marsupialis and Antidorcas marsupialis hofmeyri, most notably reflected by significant lengthening of the sole of the latter. Results were derived from comparative osteomorphological techniques, using standard anatomical nomenclature for descriptions and parametric statistics for measurements and dimensions. The configuration in A. m. hofmeyri proved useful for distinguishing between the two subspecies. The findings suggest that the osteometrical differences observed in the distal phalanges relate to different habitats occupied by the species. SIGNIFICANCE: Infraspecific morphological variation exhibited by distal phalanges in Antidorcas marsupialis is significant. The results lay the groundwork for further testing of relationships between functional morphology of foot bones and substrate in bovids.