South African Journal of Science
|Publisher||Academy of Science for South Africa (ASSAf)|
|Coverage||Vol 97 Issue 1 & 2 Jan/Feb 2001 - current|
Department of Higher Education and Training (DHET)
ScieLO SA (2016)
The Sciences Citation Index of the Institute of Scientific Information (ISI)
The vast majority of jobs of many flavours and incomes do not require the type of maths taught even in Grade 9. This is forgotten when mathematics is positioned as supremely important for the job market, or for students’ personal development.
This view, expressed in a recent article in The Conversation by Sara Muller, a researcher and doctoral candidate at the University of Cape Town, is not one generally shared.
Following the publication (Granger DE et al., Nature 2015;522:85–88) of an 26Al/10Be burial isochron age of 3.67±0.16 Ma for the sediments encasing hominin fossil StW573 (‘Little Foot’), we consider data on chert samples presented in that publication to explore alternative age interpretations. 10Be and 26Al concentrations determined on individual chert fragments within the sediments were calculated back in time, and data from one of these fragments point to a maximum age of 2.8 Ma for the sediment package and therefore also for the fossil. An alternative hypothesis is explored, which involves re-deposition and mixing of sediment that had previously collected over time in an upper chamber, which has since been eroded. We show that it is possible for such a scenario to yield ultimately an isochron indicating an apparent age much older than the depositional age of the sediments around the fossil. A possible scenario for deposition of StW573 in Member 2 would involve the formation of an opening between the Silberberg Grotto and an upper chamber. Not only could such an opening have acted as a death trap, but it could also have disturbed the sedimentological balance in the cave, allowing unconsolidated sediment to be washed into the Silberberg Grotto. This two-staged burial model would thus allow a younger age for the fossil, consistent with the sedimentology of the deposit. This alternative age is also not in contradiction to available faunal and palaeomagnetic data.
- Data on chert samples taken close to StW573 impose a maximum age for the fossil of 2.8 Ma – younger than the 3.67 Ma originally reported. We propose and explore a two-stage burial scenario to resolve the inconsistency and to reopen the discussion on the age of fossil StW573.
Two traditional cosmetic clays bear similar names in different local South African languages: vumba (Tshivenda) and ubumba (isiZulu). The wet clays are applied topically for cosmetic purposes by the respective indigenous peoples. Six samples from two South African provinces were characterised using X-ray diffraction, X-ray fluorescence spectroscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis and scanning electron microscopy. It was found that the samples differed widely with respect to mineralogy and chemical composition. This finding raises the possibility that texture characteristics during application on the skin override composition effects. Of concern is the high levels of quartz found in all the samples as it might pose a health hazard; the lowest value for quartz was 11 wt% for vumba, while values for ubumba ranged from 26 wt% to 85 wt%. All samples contained varying amounts of silicates in the form of smectite, kaolin, chlorite and plagioclase. Minor amounts of anatase and rutile were present in some samples. Three samples also contained goethite. All samples were essentially free from the toxic elements As, Pb, Hg, Cd, Se and Sb. However, they did contain low levels of chromium and heavy metals such as Cu, Zn and Ni. The pH values of ubumba slurries were slightly basic, while those of a vumba slurry were slightly acidic.
- Wide ranges of composition appear to be acceptable.
- The clays do not contain highly toxic or radioactive elements.
- The high levels of quartz present may pose a human health risk.
The antiquity of the use of hunting poisons has received much attention in recent years. In this paper we present the results of a pilot study designed to detect the presence of organic compounds, typically of less than 1200 Da, from poisonous plants that may have been used as hunting poisons in the past. We used ultra-performance liquid chromatography connected to a Synapt G2 high-resolution MS-QTOF mass spectrometer (UPLC-QTOF-MS) to provisionally identify plant-based toxins present in (1) extracts of fresh plant material, (2) a blind control recipe consisting of three plant ingredients and (3) a Hei||om arrow poison of unknown ingredients. Although not all expected toxic compounds were identified, those that were identified compared favourably with those reported in the literature and confirmed through databases, specifically the Dictionary of Natural Products and ChemSpider. MS/MS fragmentation patterns and accurate mass were used for tentative identification of compounds because archaeological residues usually contain insufficient material for unambiguous identification using nuclear magnetic resonance. We highlight the potential of this method for accurately identifying plant-based toxins present on archaeological artefacts and unique (albeit non-toxic) chemical markers that may allow one to infer the presence of toxic plant ingredients in arrow poisons. Any chemical study of archaeological material should consider the unique environmental degradative factors and be sensitive to the oxidative byproducts of toxic compounds.
- Methodology is presented for the identification of ancient plant-based arrow poisons.
Although there has been rapid expansion of higher education around the globe, such expansion has not resulted in a more equitable system. Drawing on the work of Nancy Fraser, equity in higher education is conceptualised as ‘parity of participation’ and includes both equity of access and outcomes. The tensions between expansion and equity are illustrated by comparing South Africa’s equity challenges with those of Brazil and the USA. Focusing on South Africa’s critical choices, four scenarios or possible futures are provided to illustrate some of the trade-offs and strategic choices. The main argument is that if South Africa’s higher education system continues to expand without a concomitant investment in the effectiveness of teaching and learning, it will not achieve the policy goals of equity of access and outcomes. Furthermore the investment needs to be strategically targeted to interventions that can serve as systemic levers of change for reducing drop-out rates and improving graduation rates. To this end, over the next decade the state needs to prioritise an investment in an undergraduate curriculum more ‘fit for purpose’. The investment needs to be in curriculum reform that normalises different levels of foundational provision, identifies and removes curriculum obstacles that delay or impede graduation, and provides opportunities for ‘breadth’ for all students, not only those who come from privileged backgrounds.
- If South Africa’s higher education system continues to expand without a concomitant investment in the effectiveness of teaching and learning, it will not achieve the policy goals of equity of access and outcomes.