Scielo RSS <![CDATA[South African Journal of Science]]> http://www.scielo.org.za/rss.php?pid=0038-235320190004&lang= vol. 115 num. 7-8 lang. <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>The Anthropocene</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400001&lng=&nrm=iso&tlng= <![CDATA[<b>Sydney Brenner (1927-2019): The opening game</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400002&lng=&nrm=iso&tlng= <![CDATA[<b>Rebels and Rage: Reflecting on #FeesMustFall - A review</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400003&lng=&nrm=iso&tlng= <![CDATA[<b>African science: Better but still inadequate</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400004&lng=&nrm=iso&tlng= <![CDATA[<b>Why are so many young people NEETs?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400005&lng=&nrm=iso&tlng= <![CDATA[<b>The power of books and their censorship in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400006&lng=&nrm=iso&tlng= <![CDATA[<b>The darker side of quantitative academic performance metrics</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400007&lng=&nrm=iso&tlng= <![CDATA[<b>Creating knowledge democracy in South Africa: The role of communities of practice</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400008&lng=&nrm=iso&tlng= <![CDATA[<b>Challenges and solutions to establishing and sustaining citizen science projects in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400009&lng=&nrm=iso&tlng= <![CDATA[<b>Society's needs cannot be met by applied science alone: A response to Cochrane et al. (2019)</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400010&lng=&nrm=iso&tlng= <![CDATA[<b>Reply to 'Society's needs cannot be met by applied science alone: A response to Cochrane et al. (2019)'</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400011&lng=&nrm=iso&tlng= <![CDATA[<b>An optimistic vision for biosciences in South Africa: A response to the ASSAf report on human genetics and genomics</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400012&lng=&nrm=iso&tlng= <![CDATA[<b>An optimistic vision for biosciences in South Africa: Reply to Thaldar et al. (2019)</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400013&lng=&nrm=iso&tlng= <![CDATA[<b>Human evolution in the South African school curriculum</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400014&lng=&nrm=iso&tlng= A decade after the introduction of the topic into the South African public school curriculum, the theory of evolution by natural selection is poorly understood among those who teach it, and that flawed understanding is transferred to those attempting to learn it. The curricula, support material and textbooks designed to underpin teaching and learning of evolution are often inaccurate. Deeply held religious views in the country, especially Christianity, remain a stumbling block towards understanding and accepting evolution. The lack of scientific literacy allows for the continuation of Social Darwinism and racial stereotypes and deprives the victims of those ills of the knowledge and mechanisms of thought to counter these ideas. This review explores the relatively sparse but nevertheless well-conducted research into evolution education in South Africa. We conclude that an understanding of human evolution is essential to the country's growing democracy because it provides a framework within which South Africans can understand and appreciate the diversity and heterogeneous nature of our society. SIGNIFICANCE: • Various obstacles in the teaching and learning of evolution are identified, and generalisable recommendations are provided to improve evolution education on a practical level. • Evolution education is important for the South African public: to take pride in our rich fossil resources; to understand and appreciate human diversity; to dispel the racist myths of Social Darwinism; and to ensure the success of our education system by teaching the consilience of induction and logical reasoning. • This synthesis of the research provides a starting point for anyone wanting to conduct evolution education research in South Africa in the future, specifically those in the fields of curriculum reform, life sciences or biological anthropology <![CDATA[<b>Cardioprotection conferred by rooibos (<i>Aspalathus linearis</i>): A mini review to highlight a potential mechanism of action</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400015&lng=&nrm=iso&tlng= A number of cardioprotective interventions have been identified throughout the years, and these include the use of natural antioxidants in sources like rooibos (Aspalathus linearis) tea. Recent studies have demonstrated that rooibos (either its isolated components or the crude rooibos extract/tea) confers cardioprotection in diabetic cardiomyopathy and myocardial ischaemic injury. In addition, a clinical study has shown that regular rooibos consumption reduces the risk for cardiovascular disease in adults. However, rooibos is currently not considered an official treatment against cardiac disease, mainly because the underlying mechanisms for rooibos-induced cardioprotection are not fully elucidated. Physiological actions of rooibos must be well investigated before rooibos can be used in a clinical setting as adjunct treatment for patients with heart disease. Thus, research to delineate the underlying mechanisms of rooibos-induced cardioprotection is key. In the light of the aforementioned, the available literature on rooibos-induced cardioprotection is reviewed here, highlighting the fact that rooibos preserves and maintains cardiac energy homeostasis. It is postulated that rooibos activates an AMPK-GLUT-4 glucose oxidation (cardiac energy-shortage sensing) pathway to shift cardiac energy usage, thereby conferring cardioprotection. SIGNIFICANCE: •It is hypothesised that rooibos may alter the way in which the human heart uses energy and oxygen, in order to protect the heart against disease. The heart's mitochondria are responsible for the heart's energy processes, and therefore are most likely involved in rooibos-induced cardioprotection. •Cardioprotection conferred by rooibos is likely via an AMPK-GLUT-4 glucose oxidation pathway. •The mechanism of cardioprotection is important for future studies investigating how rooibos alters cardiac mitochondria. •The more information gathered about the underlying mechanisms of rooibos, the easier it will be to recommend rooibos as an official cardioprotective intervention in patients with heart disease. <![CDATA[<b>A 20-year evaluation of PLAAS research outputs: Impact on the scholarly domain and in social media</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400016&lng=&nrm=iso&tlng= Patterns and methods of scholarly communication have changed with the growth in information technology, particularly the Internet and the social web. The changes have necessitated a broader definition of scholarly communication and the role of social media in the research process. We sought to record the body of work that the Institute for Poverty, Land and Agrarian Studies (PLAAS), a research institute at the University of the Western Cape, produced over a 20-year period (1995-2015) - the first two decades of its existence - and to measure its visibility and impact using bibliometrics and altmetrics. A survey was also carried out to investigate to what extent PLAAS researchers knew and used social media in their research practice. Scopus and Google Scholar were used as citation indices and Altmetric.com provided Altmetric scores - a measure of impact through social and mainstream media. The full list of PLAAS outputs showed a composition of 54% grey literature and 46% journal articles and monographs. Given that over half of PLAAS research outputs were in the form of grey literature, and therefore not indexed in traditional bibliometric databases, we suggest that alternative metrics be used in conjunction with bibliometrics, to measure the impact of a body of work on the scholarly domain. Although the bibliometrics in this study were a useful quantitative indicator of the impact of PLAAS research, this study was inconclusive with regard to determining the impact of the research output via altmetrics, partly because not any of the grey literature, nor any author from PLAAS, had a unique identifier, thus making it difficult to track and find quantitative indicators. Nonetheless, the potential benefit for PLAAS of using altmetrics was demonstrated in selected case studies of the output of three PLAAS researchers active on social media platforms. SIGNIFICANCE: •This study demonstrates that the use of bibliometric and altmetric analyses can yield a rich picture of research output and significance, providing insight into the patterns of scholarly communication of research and policy institutions. •The application of the research design in other research units and departments could generate results that are useful to research management within those institutions. <![CDATA[<b>Transition to open: A metrics analysis of discoverability and accessibility of LIS scholarship</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400017&lng=&nrm=iso&tlng= Metrics analysis of journal content has become an important point for debate and discussion in research and in higher education. The South African Journal of Libraries and Information Science (SAJLIS), a premier journal in the library and information science (LIS) field in South Africa, in its 85-year history, has had multiple editors and many contributing authors and has published over 80 volumes and 160 issues on a diversity of topics reflective of LIS theory, policy and practice. However, how discoverable and accessible has the LIS scholarship carried by the Journal been to its intended readership? SAJLIS transitioned to open access in 2012 and this new format in scholarly communication impacted the Journal significantly. The purpose of this paper is to report on a multiple metrics analysis of discoverability and accessibility of LIS scholarship via SAJLIS from 2012 to 2017. The inquiry takes a quantitative approach within a post-positivist paradigm involving computer-generated numerical data as well as manual data mining for extraction of qualitative elements. In using such a multiple metrics analysis to ascertain the discoverability and accessibility of LIS scholarship via SAJLIS in the period 2012 to 2017, the study employs performance metrics theory to guide the analysis. We highlight performance strengths of SAJLIS in terms of discoverability and accessibility of the scholarship it conveys; identify possible growth areas for strategic planning for the next 5 years; and make recommendations for further study for a more complete picture of performance strengths and areas for improvement. SIGNIFICANCE: •The importance of discoverability and accessibility of scholarship carried by a scholarly journal is conveyed. •The need to use multiple metrics for objective evaluation of the discoverability and accessibility of the scholarly content of a journal is emphasised. •The impact of open access on the discoverability and accessibility of the content of a scholarly journal is assessed. <![CDATA[<b>Corrosion map of South Africa's macro atmosphere</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400018&lng=&nrm=iso&tlng= The first atmospheric corrosion map of South Africa, produced by Callaghan in 1991, has become outdated, because it primarily focuses on the corrosivity of coastal environments, with little differentiation given concerning South Africa's inland locations. To address this problem, a study was undertaken to develop a new corrosion map of the country, with the emphasis placed on providing greater detail concerning South Africa's inland regions. Here we present this new corrosion map of South Africa's macro atmosphere, based on 12-month corrosion rates of mild steel at more than 100 sites throughout the country. Assimilations and statistical analyses of the data (published, unpublished and new) show that the variability in the corrosion rate of mild steel decreases significantly moving inland. Accordingly, the average first-year corrosion rate of mild steel at the inland sites (at all corrosion monitoring spots located more than 30 km away from the ocean) measured 21±12 µm/a [95% CI: 18-23 µm/a]. The minimum inland figure was about 1.3 µm/a (recorded at Droërivier in the Central Karoo) and the maxima were approximately 51 µm/a and 50 µm/a in the industrial hearts of Germiston (Gauteng) and Sasolburg (Free State), respectively. The variability in the corrosion rate of mild steel also decreased by as much as 80% between 150 m and 1000 m from the coastline. Moreover, the impact of changing altitude on the corrosivity of the environment was confirmed, particularly along the coastal regions. SIGNIFICANCE: •A new corrosion map of South Africa's inland and coastal regions is presented. •The map facilitates the identification of South Africa's least to most corrosive environments; enabling the selection of more appropriate corrosion protection solutions for general, business, mining and industrial installations. •In identifying South Africa's least corrosive areas, the use of more environmentally friendly corrosion protection procedures is potentially encouraged. <![CDATA[<b>Progressive delays in the timing of sardine migration in the southwest Indian Ocean</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400019&lng=&nrm=iso&tlng= Phenological shifts represent one of the most robust bioindicators of climate change. While considerable multidecadal records of plant and animal phenology exist for the northern hemisphere, few noteworthy records are available for the southern hemisphere. We present one of the first phenological records of fish migration for the southern hemisphere, and one of the only phenological records for the southwest Indian Ocean. The so-called 'sardine run' - an annual winter migration of sardines, northeast of their summer spawning grounds on the Agulhas Bank off the coast of Durban, South Africa - has been well documented in local newspapers given the importance placed on fishing and fishing-tourism in the region. An analysis of the first arrival dates of sardines reveals a 1.3 day per decade delay over the period 1946-2012. Although this phenological shift reveals a poor association with sea surface temperatures (SST), it coincides with a poleward shift in the position of the 21 °C mean annual SST isotherm - the threshold temperature for sardine populations. The timing of sardine arrivals near Durban corresponds closely with the number of mid-latitude cyclones passing over the Durban coastline during the months of April and May. The strength of the run is strongly associated with ENSO conditions. The complex suite of factors associated with this phenological shift poses challenges in accurately modelling the future trajectory for this migratory event. SIGNIFICANCE: •The sardine run, a significant event for tourism and fisheries, is occurring progressively later in the year •The incidence of failed sardine runs has increased in frequency over the period 1946-2012. •These changes in fish migration phenology coincide with a poleward shift in the position of the 21 °C mean annual SST isotherm. •The strength in the sardine run is strongly associated with ENSO conditions. <![CDATA[<b>Aerial map demonstrates erosional patterns and changing topography at Isimila, Tanzania</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400020&lng=&nrm=iso&tlng= Isimila is a Middle Pleistocene archaeological site located in southern Tanzania. The site is known for large surface assemblages of later Acheulean lithics such as hand axes, cleavers, scrapers and cores. While hominin remains have yet to be discovered at the site, Isimila offers a unique window into Middle Pleistocene Homo behaviour. Although Isimila has been studied extensively, the last published map of the site and surrounding area was made available in the 1970s. Here, we present an updated high-resolution map of Isimila. Data for the map were collected during aerial survey with an uncrewed(unmanned) aerial vehicle. With this map, we identified new archaeological localities, erosional patterns, newly exposed geological features and changes in site topography. The map demonstrates patterns of stone tool and raw material distribution that may support previous hypotheses of short-distance raw material transport into the area by hominins. This open-access map establishes a baseline for tracking changes to site topography in the future and serves as a unique tool to enable collaboration between researchers, museum personnel and local populations to better conserve Isimila. SIGNIFICANCE: •New potential archaeological localities and significant changes to erosional patterns at Isimila were identified. •The open access map and associated raw data provided enable researchers to track seasonal and erosional changes and anthropogenic effects, and to develop protocols for conservation of this unique site. <![CDATA[<b>An analysis of the effect of tooth wear on bovid identification</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400021&lng=&nrm=iso&tlng= Previous research provides a method for reducing the subjectivity in taxonomic identification of species in the family Bovidae by quantifying the occlusal surface of molar teeth using elliptical Fourier analysis. In this current study, we specifically test what effect medium to late tooth wear has on the identification of bovids when using the form (size and shape) of the occlusal surface to classify specimens. To achieve this, the classification results of teeth with ≥85% of their occlusal surface (training data set) were compared with the results of teeth with <85% of their occlusal surface (test data set) due to wear. In the training data set, all tribes classified correctly &gt;87% of the time with both Alcelaphini and Reduncini classifying correctly &gt;90% of the time. The worn teeth in the test data set classified correctly at lower rates, but all tribes still collectively had a good classification accuracy (&gt;60%) with classification of Alcelaphini and Tragelaphini at &gt;75% and Reduncini at &gt;65%. Hippotragini classified correctly 50% of the time and Neotragini 42%. The one worn Bovini tooth in the test data set was classified as that of a Hippotragini. The classification rates of teeth with medium to late wear were lower than the unworn teeth, but not so low as to suggest that this methodology for identifying bovid teeth is inappropriate for worn teeth, especially when supplementary to other methods. SIGNIFICANCE: •Worn teeth can be taxonomically identified by performing elliptical Fourier analysis on the occlusal surface of their teeth. •While teeth with medium to late wear correctly classify at lower rates than relatively unworn ones, the methodology is a valuable supplement to other methods for taxonomically identifying bovid teeth. •Worn teeth of the tribes Alcelaphini and Tragelaphini classify at the highest rates. <![CDATA[<b>Genetic diversity of African clawless otters (<i>A</i><i>onyx capen</i><i>sis</i>) occurring in urbanised areas of Gauteng, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400022&lng=&nrm=iso&tlng= Genetic diversity is the basis of the evolutionary potential of species to respond to environmental changes. However, restricting the movement of species can result in populations becoming less connected which can reduce gene flow and can subsequently result in a loss of genetic diversity. Urban expansion can lead to the fragmentation of habitats which affects the ability of species to move freely between areas. In this study, the genetic diversity of the African clawless otter (Aonyx capensis) in Gauteng (South Africa) was assessed using non-invasive sampling techniques. DNA was extracted from spraint (faecal) samples collected along nine rivers and genotyped using 10 microsatellites to assess population structure and genetic diversity. Samples were grouped based on locality and by catchment to determine whether isolated subpopulations exist. Genetic diversity of A. capensis in Gauteng was found to be low (mean observed heterozygosity (Ho)=0.309). Analysis of genetic structure provides support for the otter populations being panmictic with high gene flow between populations from different rivers. Results from the study indicate that the movement of A. capensis is not affected by physical barriers in urbanised areas. However, because the genetic diversity of the species in the study area is low, these animals may not be able to cope with future environmental changes. SIGNIFICANCE: •Genetic structure analysis of the sampled Gauteng otter population indicates the population is panmictic; however, a low level of genetic diversity in this population has also been identified and may affect how the population copes with future environmental changes. •Physical restrictions in urbanised areas do not appear to be affecting movement of the species. <![CDATA[<b>Biodegradability and kinetic studies on biomethane production from okra (<i>Abelmoschus </i><i>esculentus</i>) waste</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400023&lng=&nrm=iso&tlng= Emerging from the energy crisis of 2008 in South Africa, climate change concerns and the global desire to reduce high ozone-depleting emissions, renewable energy sources like biogas are gaining wide acceptance in most localities for heating and electricity. The paucity of feedstock varieties is a major challenge plaguing the sustainability of this sector. Biomethane potential, biodegradability and degradation kinetics of organic substrates are essential for assessing the suitability of feedstocks for methane generation and the overall performance of the anaerobic digestion process in biogas plants. Waste from the vegetable okra (Abelmoschus esculentus) is a novel substrate; its biodegradability and degradation dynamics in biomethane production are largely unstudied, and were therefore the aims of this research. The substrate was digested for 25 days at the mesophilic condition and the biomethane potential data were recorded. Measured data of methane yield and the elemental composition of the substrate were used to fit five models (modified Gompertz, Stannard, transference function, logistic and first-order models) to predict degradation parameters and determine biodegradability of the substrate, respectively. Low lag phase (0.143 d), positive kinetic constant (0.2994/d) and the model fitness indicator (<10) showed that transference and first-order kinetic models predicted the methane yield better than did other growth functions. The experimental methane yield was 270.98 mL/gVS, theoretical methane yields were 444.48 mL/gVS and 342.06 mL/gVS and model simulation ranged from 267.5 mL/gVS to 270.89 mL/gVS. With a prediction difference of 0.03-1.28%, all growth functions acceptably predicted the kinetics of A. esculentus waste. The findings of this study offer information on this novel substrate important for its use in large-scale biogas production. SIGNIFICANCE: •Growing interest in biogas technology as an alternative energy source for both South African rural dwellers and industries, has mounted enormous pressure on known feedstocks, and instigated the search for novel substrates. •Our study shows that okra waste is a viable feedstock for biogas production. •The suitability of the first-order kinetic model over other models in predicting okra waste degradation was highlighted. <![CDATA[<b>Estimation of radon potential through measurement of uranium concentrations in granite geology</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000400024&lng=&nrm=iso&tlng= The geology of an area can be used as a predictor for radon potential. Granite rock typically contains a high concentration of uranium and subsequent elevated emanation of radon gas. The geology of the western part of the Western Cape Province in South Africa is dominated by granite bedrock but very few studies on radon have been conducted in this area. Uranium concentrations were consequently measured on a large granite hill in the Saldanha Bay area of the Western Cape and a relationship between indoor radon and uranium concentrations was used to model radon potential on the outcrop. Results from granite rich environments in India were modelled in order to extract a relationship between indoor radon concentrations, radon exhalation rates and uranium concentrations. Radon exhalation rates greater than 0.35 Bq/m²h were predicted and estimated indoor radon concentrations in excess of 400 Bq/m³ were also predicted for the hill. The modelled results were compared with indoor radon measurements taken in the town of Paarl in the Western Cape, which sits on the same granite bedrock formation. The predicted radon potential correlated well with the physical measurements. SIGNIFICANCE: •Extensive in-situ uranium measurements were conducted by utilising a self-developed gamma-ray detection instrument (the GISPI) by means of a unique method.