Editors' Choice

January/February 2018

Did ancient giraffes once roam a savanna now submerged by the Gouritz and Breede Rivers? The recent discovery in 2016 of fossil giraffe tracks east of Still Bay on the Cape south coast – the first Pleistocene fossil giraffe tracks to be recorded in southern Africa – significantly increases the geographic range of this species. Until now there have been no reliable historical or fossil records for the giraffe south of the Orange River or northern Namaqualand. Based on correlations to dated sites nearby, the tracks were probably made around 125 000 years ago. Helm and colleagues report on the discovery which has implications for Late Pleistocene climate and vegetation in the southern Cape, because of the specialised feeding niche of giraffe populations. Evidence suggests that the currently submerged floodplains of the Gouritz and Breede Rivers supported a productive savanna during Pleistocene glacial conditions. This habitat would have been suitable for giraffe, and would likely have allowed giraffe to migrate along the southern coastal plain.

An assemblage of hominin fossils from Dinaledi Chamber, attributed to at least 15 individuals of the newly identified species Homo naledi, is strikingly different from australopith and Neanderthal sites with multiple individuals. The difference lies in the high proportion of infants and young juveniles in the Dinaledi assemblage as well as in the location of the Dinaledi fossils, which are scattered within a hidden cave chamber. About 1550 fossil specimens of a single hominin species were recovered from the Dinaledi Chamber (Cradle of Humankind, South Africa) during excavations in 2013–2014. Bolter and colleagues used 190 dental elements to identify life-history stages and attributed these elements based on their degree of development to 15 individuals: 9 immature and 6 adult individuals, including one old adult with very worn teeth. Adults were classified by sets of dentition with all the permanent teeth in place; infants (3) as those with only deciduous (or baby) teeth, juveniles (4) as those with a combination of deciduous and permanent teeth, and sub-adults (1) as those with permanent teeth that were not fully erupted. One immature individual could not be assigned to an age class. Current studies using forensic techniques are proceeding to match skeletal bones with the dental remains. The Dinaledi assemblage presents an uncommon opportunity to examine a fossil species at the population-level perspective. Additional excavations underway suggest more individuals lie in wait deep inside the cave system.

The fossilised skull of an Australopithecus africanus from Sterkfontein – well known as “Mrs Ples” – may indeed be a “Mr Ples”. Evidence obtained from an ongoing study of canine sockets and skull measurements supports the view that “Mrs Ples" is probably a small male individual. Both age and sex are factors that contribute to variation in growth and development of the cranium in australopithecines. On the basis of their comparisons of alveolar canine dimensions, Tawane and Thackeray conclude that “Mrs Ples” is the skull of a small male rather than a large female individual. The fossil is the most complete cranium of A. africanus and was discovered at the Sterkfontein Caves in the Cradle of Humankind in 1947 by Robert Broom and John Robinson. Broom claimed that it represented a female individual on the basis of canine sockets, but he did not have a large comparative sample of specimens to allow him to support this opinion. Within the last 70 years, more hominin fossils have been obtained from Sterkfontein. The view that "Mrs Ples" is a female specimen of A. africanus has been highly controversial and the skull continues to be the subject of research in the context of human evolution.

Termites are a food source with high economic and social importance and the preservation of the indigenous knowledge used during the harvesting and processing of termites should be prioritised. Netshifhefhe and colleagues surveyed over 100 harvesters, marketers and consumers from 48 villages in the Vhembe District Municipality of Limpopo Province, South Africa. Three termite species of the Macrotermes genus – mound-building termites which dominate the African savanna – are consumed, with M. falciger being the species of preference (90% of all termites). Individuals of all ages consume termites and the method of preparation preferred (by 78% of respondents) is frying. Termites are rich in proteins, fats, vitamins and many essential mineral nutrients. In addition to providing food security, income from the sale of termites can be as much as ZAR18  000 per year, and thus contributes significantly to the livelihoods of many rural families.

November/December 2017

On Saturday, I was a surgeon in South Africa, very little known. On Monday, I was world-renowned.” This was how South African heart transplant pioneer Chris Barnard summed up his instant rise to global fame after transplanting the first human heart – 50 years ago. On this 50th anniversary, Joubert examines the life of Chris Barnard and reflects on his scientific celebrity and that of scientists in South Africa today. [Read more]

 

 

Rudman and colleagues provide a first perspective on the environmental impacts of emerging solar power developments in two arid biomes of South Africa: Nama-Karoo and Savanna. They investigated the direct environmental impacts of multiple solar power developments across the landscape of the Nama-Karoo and Savanna Biomes, at a larger scale than that of the environmental impact assessment (EIA) typically undertaken. [Read more]

 

 

Geothermal exploration should quantify South Africa’s geothermal resources and its potential impact toward the national renewable energy mix. Despite evidence of anomalously high geothermal gradients, geothermal energy is not yet considered a viable energy source for South Africa. [Read more]

 

 

Most people think of algae as the green slimy substance in water. However, these microorganisms are found in an array of habitats including gold mine tailings facilities. These uninhabitable facilities need to be stabilised or revegetated to reduce pollution, leaching and erosion. They usually are stabilised with higher plants, but with variable and expensive results. [Read more]

 

 

In this time of drought, the City of Cape Town’s water should be understood and managed as a single hydrological system, not by separation of environment, sanitation and water supply. Citizens have raised concerns about sewage pollution of the ocean from marine outfalls in Table Bay and other sites in Cape Town. At the same time, the City has proposed desalination of seawater to provide drinking water. [Read more]

September/October 2017

Recent findings place doubt on whether there is an economically extractable shale gas resource in South Africa’s Main Karoo Basin. The Main Karoo Basin has been identified as a potential shale gas resource, but resource estimates (of 13–390 Tcf) are highly speculative and based on theoretical calculations – which assume that free gas is preserved in the pore space of shales – and not direct measurements of actual gas content. [Read more]

 

 

Using local timber products improves the environmental impact of the truss and building industry in South Africa. Crafford and colleagues compared the environmental impacts of three roof truss systems – South African pine, Biligom® timber and light gauge steel – using a simplified life-cycle assessment. The two timber systems had overall the lowest environmental impact. [Read more]

 

 

More inclusive and reflective conservation management practices are needed for ecological sustainability in Cape Town. Cape Town has a rapidly growing, culturally and economically diverse citizenry with differing, sometimes conflicting, perspectives on local natural resources. The informal, cash economy of Cape Town’s poor includes the deeply cultural and spiritual world of traditional medicine or muthi. [Read more]

 

 

A comprehensive comparative analysis of life-cycle costs of all power generation technologies will be indispensable in guiding the development of future energy policies in South Africa. Based on conservative estimates, the value of the impacts of a coal-fired power station over its life cycle, is double to quadruple the price of electricity. [Read more]

 

 

DNA metabarcoding can transform the study of pollination. The identification of pollen carried by flower visitors is an essential first step in pollination biology. The skill and time required to identify pollen based on structure and morphology has been a major stumbling block in this field. DNA barcoding, using DNA extracted directly from pollen, offers an innovative alternative to traditional methods of pollen identification. [Read more]

July/August 2017

Science is the source and foundation of what makes it possible to meet the need for new knowledge, for its own sake and for its application and for the ability to keep doing better as the challenges we face grow greater. Yet science and its applications are frequently taken for granted rather than being understood as fundamental and essential parts of our lives, and scientists’ contributions all too often go unacknowledged. [Read more]

 

 

Extreme rainfalls are generally becoming heavier in the Western Cape Province of South Africa. De Waal and colleagues compared extreme rainfall in the 1980–2009 period to that in 1950–1979 and show that 63% of 76 rainfall stations analysed displayed an increase in rainfall extremes. There are similar trends of change for both 20- and 50-year return periods.  [Read more]

 

 

Women members in national science academies remain far below parity with men at 12%. Women members are better represented in the social sciences, humanities and arts, but rarely at over 20%; in the natural sciences and engineering, women’s membership remains well below 10%. [Read more]

 

 

Containing the spread of the Ebola virus disease outbreak in West Africa required more than treating the symptoms of the disease – both scientific and non-scientific interventions were required, according to Falade and Coultas. Science influences our beliefs and behaviour, but the process is not always with the speed envisaged by scientists. [Read more]

 

 

The failure of African Bank was a shock to South African markets and introduced significant systemic risk in the financial system. Could this risk have been highlighted earlier and was there a way to avoid this outcome? Sanderson and colleagues applied option valuation techniques to assess whether the markets warned of a possible African Bank failure. [Read more]

May/June 2017

Editori's Choice: May/June 2017

Continued investment in promoting multidisciplinary research through national research programmes such as SANAP – the South African National Antarctic Programme – is essential for South Africa to remain globally competitive in the region to our south – a key geopolitical region. Antarctica, the sub-Antarctic islands and surrounding Southern Ocean are regarded as one of the planet’s last remaining wildernesses. [Read more]

 

 

Editor's Choice: May/June 2017

Young men from poor socio-economic areas are most at risk of blunt force homicide in Cape Town. Clark and colleagues examined over 15 000 autopsy reports from a five-year period (2010–2014) from Salt River Mortuary in Cape Town’s West Metropole. The prevalence of blunt force homicide during this time was 5.32% – comparable with other regions in South Africa. [Read more]

 

 

Editor's Choice: May/June 2017

Cape snoek – often seen as a low-value fish – is a healthy and inexpensive food that is high in protein and omega-3 fatty acids and low in fat. Cape snoek is a popular food choice among poorer and working-class households in the Western Cape and is prepared in several ways, from smoking to oven baking, microwave cooking to braaing. [Read more]

 

 

Editor's Choice: May/June 2017

 Policymakers should look to social norms interventions as a cost-effective tool to address key public health issues in South Africa. Ganz and colleagues propose that such interventions have widespread and significant potential to address issues of public health in South Africa. [Read more]

 

 

 Editor's Choice: May/June 2017

 The MeerKAT telescope – a precursor to the Square Kilometre Array – will rely on optical fibres to link the telescope receivers to a central processor point. MeerKAT requires highly accurate and stable clock distribution over up to 12 km of optical fibre to remote dishes. The clock distribution is required for digitisation of astronomical signals and instrument control. [Read more]

March/April 2017

Mathematics and...

The concept of zero is probably one that affects our lives daily, but have you ever wondered where it originated? Engagements of a mathematical nature date back to antiquity in many different parts of the world, yet today the value and potential of mathematics is not fully recognised. This potential through interdisciplinary collaborations among the mathematical sciences was explored in a recent workshop entitled ‘Finding Synergies in the Mathematical Sciences’ hosted by the Academy of Science of South Africa (ASSAf). Adler, Reddy, Hofmeyr, Wittenberg and Nongxa explored the synergies between mathematics and those fields. [Read more]

 

 

The unsolved case of Little Foot’s age

Little Foot cannot be more than 2.8 million years old, according to Kramers and Dirks. This age differs from that reported previously by Granger et al. (Nature 2015;522:85–88) of 3.67±0.16 million years. Interpreting the ages of hominin fossils is very important for understanding the timeline of human evolution. Little Foot is a complete Australopithecus skeleton, found in 1997/1998 in sediments of the Silberberg Grotto in the Sterkfontein Caves. [Read more]

 

 

Vumba and ubumba: Traditional cosmetic clays characterised

High levels of quartz – of up to 85% – were found in two traditional cosmetic clays, suggesting that their use may pose a potential health risk as there is evidence of carcinogenicity at levels above 15%. The clays also contained low levels of chromium and the heavy metals copper, zinc and nickel, but were otherwise free from toxic elements. The two clays – which bear similar names in two local languages (vumba in Tshivenda and ubumba in isiZulu) – are applied topically for cosmetic purposes by the respective indigenous peoples. [Read more]

 

 

The first chemical weapons: Origins of hunting poisons

When did people start using poisoned arrows to hunt prey? Wooding and colleagues present a method that can accurately identify plant-based toxins present on archaeological artefacts as well as other unique chemical markers that may allow chemists to infer the presence of toxic plant ingredients applied to ancient weapons. Accurately identifying remnants of ancient poisons is a challenging task, as organic molecules are subject to degradation over time and seldom resemble their parent compound. [Read more]

 

 

January/February 2017

Editor's Choice: January/February 2017

Targeting athletes’ self-awareness may have benefits for improving their mental toughness and enhancing competitive performance outcomes. In the highly competitive sporting environment, mental toughness is often considered the mental edge that underpins sporting success. With interest growing in how athletes’ mental toughness can be changed, Cowden explored whether competitive tennis players who are more self-aware tend to be mentally tougher. [Read more]

 

 

Editor's Choice: January/February 2017

Stormwater harvesting can improve water security in South Africa’s urban areas. The ongoing drought in South Africa has left many parts of the country with extremely limited access to water. If a future water crisis is to be averted, the country needs to conserve current water supplies, reduce its reliance on conventional surface water schemes, and seek alternative sources of water supply. [Read more]

 

 

Editor's Choice: January/February 2017

Targeted policy initiatives aimed at enhancing household income are important in the Eastern Cape, Limpopo and KwaZulu-Natal Provinces – the provinces identified as the poorest in South Africa. Households in traditional and urban formal areas diversify income sources – with up to four income sources – to a greater extent than households in urban informal and rural formal settlements in these provinces. [Read more]

 

 

Editor's Choice: January/February 2017

The Klip River system – a natural wetland southwest of Johannesburg – is vital to the region’s water supply, through sequestering contaminants that would otherwise enter the Vaal River system and cause widespread pollution. Humphries and colleagues found considerable enrichments in toxic metals observed within the Klip River peats – thus highlighting the value of this system in sequestering metals from polluted water. [Read more]

 

 

Editor's Choice: January/February 2017

South Africa’s higher education system stands yet again at a critical crossroad. A ‘twin’ investment strategy is required on the part of the State to remove both financial obstacles and academic obstacles that prevent the best products of our public and private schooling from successfully graduating. The student protests of 2015/2016 have put a sharp spotlight on the issue of fees and the unaffordability of tertiary education for the majority of our best qualified matriculants. [Read more]