South African Journal of Science - latest Issue
Volumes & issues
Volume 112, Issue 9-10, 2016
Author J. Butler-AdamSource: South African Journal of Science 112 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0176More Less
So much has been written, over the past 11 months, about '#feesmustfall' and '#nofees', that there is little, if anything, left to say. The Council on Higher Education has presented its report to the Minister of Higher Education; the Presidential Commission continues with its work; and Universities South Africa has made representations to the Minister and to the Parliamentary Portfolio Committee on Higher Education. All that is needed is a decision (now arrogated from university councils it would seem) - and the means of dealing with whatever will follow the decision.
Author Michael LieberSource: South African Journal of Science 112 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0172More Less
Regarding the significance of the Golden Ratio, 1.62, in phenomena as described by Boeyens and Thackeray in 2014, I also - in a 1998 publication - demonstrated its significant and unifying role in physical and biological reality. It was demonstrated that the Golden Ratio is an inherent, dimensionless biological constant composing the dimensional physical constants of physics. In that article, it was also shown that this biological constant reflects a regenerative, adaptive or accommodating process operating through all scales of reality, from the sub-quantum, through the biological, to the cosmological level of organisation, and in so doing, giving a fractal unity to such realities, uniting quantum reality with cosmological reality, hence quantum reality with the reality of general relativity. Through a simple mathematical analysis, it was also found and noted that this dimensionless biological constant denotes a near infinitesimal, regenerative feature of space-time. Also described was how the dimensionless biological constant defined reality or space-time as having a vortical or spiral morphology. In 1949, the mathematician Kurt Godel, in solving in a new way the differential field equations from general relativity, showed the universe as having a spiral or vortical space-time geometry through the rotation of matter.
Author Thalia BrussowSource: South African Journal of Science 112, pp 3 –5 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0178More Less
Knowledge is the currency of a thriving economy. Generating and engaging with that knowledge delivers innovative ideas that empower and sustain nations. That is why the National Research Foundation (NRF) of South Africa annually celebrates the work of our country's finest researchers through the NRF awards.
The Marine Protected Areas debate : implications for the proposed Phakisa Marine Protected Areas Network : news & viewsAuthor Kerry SinkSource: South African Journal of Science 112, pp 6 –9 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0179More Less
South Africa recently had the privilege of hosting prominent fisheries scientist Professor Ray Hilborn from Washington University who stimulated lively discussion on global stock status, food production, impacts of trawling on the seabed, fisheries management and Marine Protected Areas (MPAs). Professor Hilborn gave a seminar billed as 'Fisheries Myths' on 25 August 2016 and the following day participated in a formal debate at the Two Oceans Aquarium on South Africa's MPA expansion strategy and the need for additional MPAs. The debate was held between Professors Ray Hilborn and Doug Butterworth (Marine Resource and Assessment Management Group, Applied Mathematics Department, University of Cape Town) speaking against the strategy and expansion, and Dr Jean Harris (Ezemvelo KwaZulu-Natal Wildlife and Pew Fellow) and Professor Colin Attwood (Department of Biological Sciences, University of Cape Town) speaking in favour of additional MPAs. The debate examined the need for MPA expansion; the effect of MPAs on fisheries; and the role of MPAs in fisheries management, food security and biodiversity protection; and interrogated targets to increase ocean protection.
AUFWIND : an ambitious German microalgae project for producing third-generation biofuels : news & viewsAuthor Johan U. GrobbelaarSource: South African Journal of Science 112, pp 10 –11 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0174More Less
The term 'microalgae' has no taxonomic meaning, except that it refers to a spectrum of photosynthesising microorganisms from Protista and Archaebacteria, including chlorophyta (green algae) and cyanobacteria (blue-green algae). Microalgae have been studied in the laboratory, in mass outdoor cultures and in nature for more than a century. They are grown for a variety of potential applications, which include basic research on photosynthesis, the production of lipids for energy, bioremediation, anti-microbial substances, cheap protein for animal and human nutrition, and the production of various bio-chemicals.
Author J. Francis ThackeraySource: South African Journal of Science 112, pp 12 –13 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0170More Less
About 60 years ago, a South African anatomist, Joseph Weiner, published a book entitled The Piltdown Forgery, exposing a hoax that had been perpetrated about 100 years ago at the site of Piltdown in Sussex, England. The announcement of 'Piltdown Man' - classified as Eoanthropus dawsoni and believed to be a hominid apparently associated with Pleistocene fauna - had been made by Smith Woodward of the British Museum (Natural History) at Burlington House in London on 18 December 1912. However, it turned out that the 'hominid' was a fabrication in which a subfossil human cranium and a modern orangutan jaw (both stained brown) were placed together in a gravel pit, thereby confusing palaeontologists. In the process, Raymond Dart's announcement of the 'Taung Child' (Australopithecus africanus) from South Africa was disregarded by many (including the anatomist Sir Arthur Keith) who questioned Dart's claim that this small-brained fossil represented a genuine Pleistocene hominid.
Author Robin M. CreweSource: South African Journal of Science 112, pp 14 –15 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0175More Less
Scholarly academies have been in existence for about 350 years, with the oldest being those that were established in Europe in the 17th century. These institutions consist of groups of individuals who are elected by their peers to be members (often called fellows); since the middle of the 19th century, election to the august ranks of most academies has been based on recognition of the outstanding scholarly work done by those proposed for membership. Academies have made the transition from being learned societies to being select groups of eminent scholars who are often widely admired in their countries.
Response to Thackeray (2016) - The possibility of lichen growth on bones of Homo naledi : were they exposed to light? : commentarySource: South African Journal of Science 112, pp 16 –20 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0177More Less
Thackeray questions the hypothesis of deliberate body disposal in the Rising Star Cave by Homo naledi, as proposed by Dirks and colleagues. Thackeray proposes that lichens produced mineral staining on the skeletal remains of H. naledi. As lichens require some exposure to light, in Thackeray's opinion, the presence of mineral staining necessitates either a direct entrance deep into the Rising Star Cave that once admitted light into the Dinaledi Chamber, or relocation of mineral-stained bones from a location exposed to light. Here we consider multiple lines of evidence that reject Thackeray's hypothesis that lichens deposited mineral staining upon the surface of these skeletal remains. We welcome the opportunity to address the inferences presented by Thackeray, and further hope that this response may dispel misinterpretations of our research, and of other areas of the scientific literature that bear upon site formation processes at work within the Rising Star Cave system.
Authors: Isabelle J. Ansorge, Geoff Brundrit, Jean Brundrit, Sarah Fawcett, David Gammon, Tahlia Henry, Tammy Morris, Izidine Pinto, Marcel Du Plessis, Raymond Roman, Rosemary Dorrington, Ian Meiklejohn, Juliet Hermes, Beate Holscher, Jethan d'Hotman, Tammy Morris, Clinton Saunders, Fannie W. Shabangu, Marc De Vos, David R. Walker and Gavin LouwSource: South African Journal of Science 112, pp 21 –24 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0171More Less
The Department of Science and Technology's (DST's) 10-year Global Change Grand Challenge programme requires platforms to 'attract young researchers to the region and retain them by exciting their interest in aspects of global change; while developing their capacity and professional skills in the relevant fields of investigation'. In addition, in July 2014, President Zuma officially launched Operation Phakisa and announced that a key target of this Oceans Economy initiative would be 'for the Department of Higher Education and Training to drive alignment between theoretical and workplace learning'.
SEAmester - South Africa's recently established Class Afloat - achieves just that. SEAmester introduces marine science as an applied and cross-disciplinary field to students who have shown an affinity for core science disciplines. It identifies with government's National Development Plan on education, training and innovation - critical to South Africa's long-term development and investment in this sector.
SEAmester has a long-term vision aimed at building capacity within the marine sciences by coordinating and fostering cross-disciplinary research projects and achieving this goal through a highly innovative programme. The strength of SEAmester is that postgraduate students combine theoretical classroom learning with the application of this knowledge through ship-based, and more importantly, hands-on research. The state-of-the-art research vessel, SA Agulhas II, provides an ideal teaching and research platform for this programme; its size, comfort and shipboard facilities allow large groups of students and lecturers to productively interact over a period of 10 days.
South Africa in the Antarctic Circumnavigation Expedition : a multi-institutional and interdisciplinary scientific project : commentarySource: South African Journal of Science 112, pp 25 –28 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/a0173More Less
The polar regions are more critically affected by climate change than any other region on our planet. On the Antarctic continent and in its surrounding oceans, the effects of climate change are likely to be dramatic, and include largescale catastrophic ice melt, loss of habitat and biodiversity, and global sea level rise. The 'Southern Ocean' refers to the region where Atlantic, Indian and Pacific Ocean waters come together to encircle Antarctica. These waters connect the different ocean basins by linking the shallow and deep limbs of the global ocean current system ('overturning circulation') and play a critical role in storing and distributing heat and carbon dioxide (CO2). The Southern Ocean thus regulates not only the climate of the Antarctic, but of the entire earth system. By extension, the capacity of the global ocean to ameliorate earth's changing climate is strongly controlled by the Southern Ocean.
Marine phytoplankton (microscopic plants inhabiting the sunlit upper ocean) convert CO2 (an inorganic form of carbon) dissolved in surface waters into organic carbon through photosynthesis. This organic carbon fuels upper trophic levels such as fish, mammals and birds, and a portion sinks into the deep ocean where it remains stored for hundreds to thousands of years. This mechanism, which lowers the atmospheric concentration of CO2, is termed the 'biological pump'. The efficiency of the global ocean's biological pump is currently limited by the Southern Ocean, where the macronutrients (nitrate and phosphate) required for photosynthesis are never fully consumed in surface waters. In theory, increased consumption of these nutrients could drive higher organic carbon removal to the deep ocean, enhancing the oceanic uptake of atmospheric CO2. Indeed, more complete consumption of Southern Ocean nutrients is a leading hypothesis for the decrease in atmospheric CO2 that characterised the ice ages.
Despite the global importance of the Southern Ocean, knowledge of the controls on and interactions among the physical, chemical and biological processes operating in Antarctic ecosystems is limited, largely because of a scarcity of in-situ observational data, compounded by the challenge of integrating siloed scientific fields. Given predictions that diverse aspects of Southern Ocean physics and carbon biogeochemistry are likely to change in the coming decades, a transdisciplinary approach to studying Antarctic systems is critical.
A snow forecasting decision tree for significant snowfall over the interior of South Africa : review articleSource: South African Journal of Science 112, pp 29 –38 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20150221More Less
Snowfall occurs every winter over the mountains of South Africa but is rare over the highly populated metropolises over the interior of South Africa. When snowfall does occur over highly populated areas, it causes widespread disruption to infrastructure and even loss of life. Because of the rarity of snow over the interior of South Africa, inexperienced weather forecasters often miss these events. We propose a five-step snow forecasting decision tree in which all five criteria must be met to forecast snowfall. The decision tree comprises physical attributes that are necessary for snowfall to occur. The first step recognises the synoptic circulation patterns associated with snow and the second step detects whether precipitation is likely in an area. The remaining steps all deal with identifying the presence of a snowflake in a cloud and determining that the snowflake will not melt on the way to the ground. The decision tree is especially useful to forecast the very rare snow events that develop from relatively dry and warmer surface conditions. We propose operational implementation of the decision tree in the weather forecasting offices of South Africa, as it is foreseen that this approach could significantly contribute to accurately forecasting snow over the interior of South Africa.
New light on vitamin B12 : the adenosylcobalamin-dependent photoreceptor protein CarH : review articleAuthor Susan M. ChemalySource: South African Journal of Science 112, pp 39 –47 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20160106More Less
Adenosylcobalamin (AdoCbl), or coenzyme B12, is a cofactor for enzymes important in metabolism in humans (and other mammals) and bacteria. AdoCbl contains a Co-C bond and is extremely light sensitive, but, until recently, this light sensitivity appeared to have no physiological function. Recently, AdoCbl has been found to act as cofactor for a photoreceptor protein (CarH) that controls the expression of DNA coding for transcription of the proteins needed for synthesis of carotenes in certain non-photosynthetic bacteria. In 2015, the X-ray crystal structures of two dark states of the photoreceptor protein from the bacterium Thermus thermophilus were determined: CarH bound to AdoCbl and CarH bound to a large portion of the cognate DNA operator (and AdoCbl); a light state was also determined in which CarH was bound to cobalamin in which the Co-C bond had been broken. The breaking of the Co-C bond of Ado-Cbl acts as a trigger for the regulatory switch that allows the transcription of DNA. In the two dark states AdoCbl is bound to a conserved histidine from CarH, which displaces the lower 5,6-dimethylbenzimidazole ligand of AdoCbl. In the light state the 5'-deoxyadenosyl group of AdoCbl is replaced by a second histidine from CarH, giving a bis-histidine cobalamin and 4',5'-anhydroadenosine. Genes for B12-dependent photoreceptors are widespread in bacteria. Control of DNA transcription may represent an evolutionarily ancient function of AdoCbl, possibly pre-dating its function as a protein cofactor.
Reducing substance use and sexual risk behaviour among men who have sex with men in South Africa : research articleSource: South African Journal of Science 112, pp 48 –52 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20150425More Less
Men who have sex with men have been identified as a population at risk of acquiring and transmitting HIV. Studies in South Africa have reported a high prevalence of HIV, as well as high levels of alcohol and other drug use, among men who have sex with men, and the use of substances (alcohol and drugs) to facilitate their sexual encounters. Since 2007, interventions focused on prevention have been rolled out to vulnerable men who have sex with men and who also use alcohol or other drugs. The interventions include community-based outreach; provision of information on HIV/AIDS, substance abuse, and safer sex practices; and the development of risk-reduction plans. Among 195 men who participated in our study, there were significant reductions in the proportion who used cannabis and ecstasy, including the use of these drugs during sex. No reduction was observed in the use of any other substances. In general, after the intervention our participants reported less frequent use of alcohol and drugs and greater engagement in safer sexual practices. Despite these encouraging findings, the combination of substance use while engaging in sex had actually increased. The study findings suggest that interventions that target men who have sex with men, and who use alcohol and other drugs, could reduce risk behaviours in this population.
Source: South African Journal of Science 112, pp 53 –62 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20150424More Less
The long-standing tradition of classifying South Africa's biogeographical area into biomes is commonly linked to vegetation structure and climate. Because arthropod communities are often governed by both these factors, it can be expected that arthropod communities would fit the biomes. To test this hypothesis, we considered how well arthropod species assemblages fit South Africa's grassy biomes. Arthropod assemblages were sampled from six localities across the grassland and savanna biomes by means of suction sampling, to determine whether the two biomes have distinctive arthropod assemblages. Arthropod samples of these biomes clustered separately in multidimensional scaling analyses. Within biomes, arthropod assemblages were more distinctive for savanna localities than grassland. Arthropod samples of the two biomes clustered together when trophic groups were considered separately, suggesting some similarity in functional assemblages. Dissimilarity was greatest between biomes for phytophagous and predacious trophic groups, with most pronounced differentiation between biomes at sub-escarpment localities. Our results indicate that different arthropod assemblages do fit the grassy biomes to some extent, but the pattern is not as clear as it is for plant species.
Source: South African Journal of Science 112, pp 63 –70 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20150412More Less
In the field of biochemistry, the use of external representations such as static diagrams and animations has increased rapidly in recent years. However, their effectiveness as instructional tools can be hindered if students lack the visual literacy and cognitive skills necessary for processing and interpreting such representations. We aimed to identify and assess visualisation skills necessary for effective processing of external representations in biochemistry. We used a modified Bloom's taxonomy to identify the cognitive skills essential for optimal visual literacy, and designed probes based on those skills to develop a test instrument. Student responses to the probes were scored and processed with the Rasch model. This approach enabled us to rate the degree of difficulty of each visualisation skill on a linear logit scale, and to generate a person-item map to measure biochemistry students' level of visual literacy. The results showed that the identified visualisation skills could be measured reliably, and the Rasch model was effective both for ranking the skills according to level of difficulty and for estimating a student's relative level of visual literacy.
Pesticide management practices among rural market gardening farmers near Harare, Zimbabwe : research articleSource: South African Journal of Science 112, pp 71 –75 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20150443More Less
In 2014, we carried out a survey in Chinamhora and Chihota communal lands on the outskirts of Harare city, with the aim of understanding pesticide management practices among market gardening farmers. The farmers grew vegetables that mostly included tomatoes, cabbages, rape, cucumbers, onions and carrots, and they used mainly organophosphates and pyrethroids to control pests. A questionnaire was administered to 119 male heads of households across both study areas. The questionnaire contained 13 closed-ended questions in three sections: source and quality of pesticides, handling and use, and storage and disposal of pesticides used to protect crops. The study identified numerous gaps related to the handling of pesticides. Although the quality of labelling and packaging can largely identify the quality of pesticide, most of the farmers (77.3%) could not distinguish between genuine and counterfeit pesticides; approximately half (47.9%) of the farmers were not concerned about expiry dates; 27% did not observe post-spray periods; and 63% did not take precautions according to colour-coding of the pesticides. Also of concern were the large numbers of farmers who were not using protective coveralls (54.3%); a substantial number who were not using knapsacks for spraying (21.8%); poor storage of the pesticides, as shown by the variation in storage facilities; the use of empty pesticide containers for domestic purposes (20.2%); and lack of strict adherence to recommended dose levels, with some farmers (28.6%) merely estimating the dilution of pesticides. Training through outreach programmes is recommended.
Do African microfinance institutions need efficiency for financial stability and social outreach? : research articleSource: South African Journal of Science 112, pp 76 –83 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20150474More Less
Microfinance institutions (MFIs) have the dual objective of providing social welfare and financial stability. We evaluated the financial efficiency of MFIs in sub-Saharan African countries by comparing their regional performances during the period 2004-2013. We addressed prevailing MFI heterogeneity by using the concept of 'metafrontier'. The results showed that on an average, more than half the MFIs showed a drop in productivity. The measure of how much one country gets closer to or further away from world frontier technology is commonly known as the TGC score. In world frontier technology, East and South Asian countries have taken the lead (TGC score 1.0048) while sub-Saharan African countries lag behind (TGC score 1.0020). Most East and South Asian countries have a TGC score of 1, and most sub-Saharan African countries have a TGC score less than 1. This signifies that Asian countries lead world frontier technology and most African countries do not. The decomposition of efficiency scores showed that with regard to technical changes, African nations had progressed on average only 0.01%, and efficiency change scores had regressed by 0.59% annually.
San and Nama indigenous knowledge : the case of |nhora (Pteronia camphorata) and its medicinal use : research articleSource: South African Journal of Science 112, pp 84 –92 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20160044More Less
A hitherto unidentified medicinal plant is here identified for the first time as Pteronia camphorata (L.) L.,an aromatic shrub of the Asteraceae family endemic to the western and southern coastal region of South Africa. The plant was described in this journal by Laidler in 1928 as 'D|nhora buchu', and is one of the important types of buchu used by the Nama people. We report the traditional medicinal uses among San and Nama people, based on our interviews with rural participants. These include the treatment of colds, influenza, chest ailments and tuberculosis, as well as convulsions, haemorrhoids and inflammation of the neck. The major and minor chemical compounds of the essential oil that is produced by the plant are identified, together with the site of accumulation of this volatile oil within the leaf. We also investigated the plant's antimicrobial activity against a selection of a yeast and two Gram-negative and one Gram-positive bacteria, all of which are associated with respiratory infections. P. camphorata is scientifically poorly known but is an important San and Nama traditional remedy. Our study not only prevents the potential loss of historically important indigenous knowledge, but also provides the first scientific evidence to validate the traditional use of |nhora against upper and lower respiratory tract infections, including tuberculosis. This detailed study has wider application in demonstrating the fragility of the oral-traditional knowledge of a scientifically neglected indigenous group. It also highlights the scientific and practical importance of preserving traditional plant-use knowledge within a botanically diverse region.
Implications of summer breeding frogs from Langebaanweg, South Africa : regional climate evolution at 5.1 mya : research articleSource: South African Journal of Science 112, pp 93 –99 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20160070More Less
No direct palaeoclimatic proxies have been available to indicate the seasonality or amount of rainfall on the west coast of southern Africa during the Early Pliocene. The Benguela Upwelling System (BUS) is today one of the factors responsible for the present-day aridity on the west coast of southern Africa. The initiation of the BUS is frequently linked to the entrenchment of aridity and the establishment of the current winter rainfall pattern on the west coast; however, marine proxies are inconclusive regarding the effects of past fluctuations in the BUS and sea surface temperatures on the rainfall regime. Neither the fossil evidence nor the fact that plants using the C3 photosynthetic pathway predominate at this time, provide direct evidence of winter rainfall at Langebaanweg. We challenge certain assumptions which are commonly made in the literature regarding the timing of inception of a winter rainfall regime on the west coast and the onset of aridity in the Langebaan region, and provide new evidence as to seasonality of rainfall at Langebaanweg in the Early Pliocene. Herein, the identification of frog species from the genus Ptychadena from Langebaanweg provides new and compelling evidence for a summer rainfall regime, or of at least significant summer rainfall, at 5.1 mya in the southwestern Cape of South Africa.
Differential involvement of ascorbate and guaiacol peroxidases in soybean drought resistance : research articleSource: South African Journal of Science 112, pp 100 –103 (2016) http://dx.doi.org/http://dx.doi.org/10.17159/sajs.2016/20160028More Less
Soybean (Glycine max L.) is a small but growing component of the agricultural economy of South Africa and is predicted to become a major crop in Africa because of its high protein content. Drought induction at flowering or early stages of pod development has detrimental effects on soybean yield. As antioxidative enzymes play a protective role in plants during various abiotic stress conditions, this study was conducted to investigate how ascorbate (Enzyme Commission (EC) number 184.108.40.206) and guaiacol (EC: 220.127.116.11) peroxidases are involved in soybean drought resistance at different maturity stages (flowering and pod development). We also investigated whether the levels of these enzymes decline with plant maturity. Three tolerant soybean genotypes (G1, G2, G3) and a susceptible genotype (G4*) were used. These cultivars were categorised according to their sensitivity to drought stress in previous studies. The activity of ascorbate peroxidase was significantly induced by drought stress at both growth stages with higher activity in the resistant than susceptible plants, strongly supporting the protective role of this enzyme against drought stress at both developmental stages. The guaiacol peroxidase activity was induced to higher levels in the resistant than in the susceptible plants at flowering only, with no significant increase observed at pod development stage, indicating its selective protective involvement against drought stress. Interestingly, the levels of these enzyme activities were induced in all cultivars at both developmental stages, irrespective of drought stress, indicating that their activities increased with maturity.