Scielo RSS <![CDATA[South African Journal of Science]]> http://www.scielo.org.za/rss.php?pid=0038-235320120001&lang=en vol. 108 num. 1-2 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>New green paper on higher education lacks a clear vision</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100001&lng=en&nrm=iso&tlng=en <![CDATA[<b>The oldest animal fossils</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100002&lng=en&nrm=iso&tlng=en <![CDATA[<b>Powering Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100003&lng=en&nrm=iso&tlng=en <![CDATA[<b>John Dawson Skinner</b>: <b>Mammalogist (1932-2011)</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100004&lng=en&nrm=iso&tlng=en <![CDATA[<b>Sharp-nosed at Sharpeville</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100005&lng=en&nrm=iso&tlng=en http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100006&lng=en&nrm=iso&tlng=en <![CDATA[<b>The diplomats fiddle while Africa burns</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100007&lng=en&nrm=iso&tlng=en <![CDATA[<b>Potential technological spin-offs from MeerKAT and the South African Square Kilometre Array bid</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100008&lng=en&nrm=iso&tlng=en <![CDATA[<b>Traversing the global oil summit (aka Hubbert's Peak)</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100009&lng=en&nrm=iso&tlng=en <![CDATA[<b>Building a nation one project at a time</b>: <b>Reply to 'On human evolution,<i> Australopithecus sediba</i> and nation building'</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100010&lng=en&nrm=iso&tlng=en <![CDATA[<b>Why did schistosomiasis disappear from the southern part of the Eastern Cape?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100011&lng=en&nrm=iso&tlng=en We reviewed the early literature and maps of the occurrence of urogenital schistosomiasis (bilharzia) in the Eastern Cape, South Africa from the 1860s until its decline from about 1900 and reappearance in 2002. Although this decline in transmission has received little attention to date, clinical descriptions of the disease over this period indicate that infection was common, probably patchy, although sometimes with severe morbidity. The long period of quiescence between 1900 and 2002 is thought to be as a result of several factors, but primarily because of the impact of the area's cold winters and drought-prone climate on the survival and reproduction of both the snail intermediate host Bulinus africanus and the intramolluscan stages of the parasite. The concept of an outbreak area is invoked to describe the occurrence of intense urogenital schistosomiasis transmission in localised areas for relatively short periods of up to 35 years in this the southernmost part of its range in Africa, a suboptimal environment for transmission. <![CDATA[<b>The first stratigraphic column in South Africa, from Hondius (1652), and its modern correlatives</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100012&lng=en&nrm=iso&tlng=en In 1647 the Dutch ship Haarlem, en route from Batavia to the Netherlands Republic, was wrecked in Table Bay. The survivors were encamped over the next year before they were rescued in a fort they constructed called Sandenburgh. Their successful sojourn in the Cape led directly to the establishment of the Dutch colony there in 1652. They survived by living on hunted cormorants and penguins, bartered cattle and sheep, and by drinking fresh water obtained from a well which they sank to a depth of 20 m. The sequence of sediments encountered in the well was recorded by Jodocus Hondius III, grandson of the famous mapmaker, in a book published in 1652, based on accounts given to him by the sailors from the Haarlem. A comparison of the stratigraphy recorded in the well (five sedimentary units) with the Pleistocene and Holocene stratigraphy known from modern studies of these coastal sediments, shows a very good correspondence in terms of lithologies and thicknesses, and attests to the veracity of the sources that provided Hondius with his information. This singular case of a detailed stratigraphic column is interesting in the light it throws on the rudimentary understanding of rock types, stratigraphy and hydrology by Dutch sailors in the mid-17th century, at the beginnings of South African colonial history, more than a decade before the study of stratigraphy was initiated by the work of Steno. The measurements recorded in the description of the well are some of the earliest quantitative data recorded in the history of South African science. <![CDATA[<b>The South African National Vegetation Database</b>: <b>history, development, applications, problems and future</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100013&lng=en&nrm=iso&tlng=en Southern Africa has been recognised as one of the most interesting and important areas of the world from an ecological and evolutionary point of view. The establishment and development of the National Vegetation Database (NVD) of South Africa enabled South Africa to contribute to environmental planning and conservation management in this floristically unique region. In this paper, we aim to provide an update on the development of the NVD since it was last described, near its inception, more than a decade ago. The NVD was developed using the Turboveg software environment, and currently comprises 46 697 vegetation plots (relevés) sharing 11 690 plant taxa and containing 968 943 species occurrence records. The NVD was primarily founded to serve vegetation classification and mapping goals but soon became recognised as an important tool in conservation assessment and target setting. The NVD has directly helped produce the National Vegetation Map, National Forest Type Classification, South African National Biodiversity Assessment and Forest Type Conservation Assessment. With further development of the NVD and more consistent handling of the legacy data (old data sets), the current limitations regarding certain types of application of the data should be significantly reduced. However, the use of the current NVD in multidisciplinary research has certainly not been fully explored. With the availability of new pools of well-trained vegetation surveyors, the NVD will continue to be purpose driven and serve the needs of biological survey in pursuit of sustainable use of the vegetation and flora resources of the southern African subcontinent. <![CDATA[<b>How do HIV and AIDS impact the use of natural resources by poor rural populations? The case of wild animal products</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100014&lng=en&nrm=iso&tlng=en As a result of heightened financial and food insecurity, populations adversely affected by HIV and/or AIDS may be more likely to utilise wild natural resources to supplement their diet and livelihoods. Should this effect be pronounced, HIV and AIDS may pose a serious environmental threat. We explored the hypothesis that the presence of factors in the household, such as chronic illness in and recent mortality of individuals in a high HIV-risk age group, as well as the fostering of orphans, are associated with increased utilisation of wild animal products (WAPs) at the household level. We randomly surveyed 519 households from four sites in rural South Africa, recording household socio-economic status, the utilisation of wild animal products and health and demographic factors attributed to HIV or AIDS. Binary logistic regressions were used to test if households with markers of HIV and/or AIDS affliction were more likely to have a higher incidence and frequency of WAP utilisation relative to non-afflicted households, after adjusting for socio-economic and demographic variables. We found that, although households with markers of HIV and/or AIDS were generally poorer and had higher dependency ratios, there was no evidence to support the hypothesis that WAP harvesting was associated with either poverty, or markers of HIV and/or AIDS affliction. Our findings suggest that generalisations about a possible interaction between HIV and/or AIDS and the environment may not uniformly apply to all categories of natural resources or to all user groups. <![CDATA[<b>Observations of a middle atmosphere thermal structure over Durban using a ground-based Rayleigh LIDAR and satellite data</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100015&lng=en&nrm=iso&tlng=en Studying the middle atmospheric thermal structure over southern Africa is an important activity to improve the understanding of atmospheric dynamics of this region. Observations of a middle atmosphere thermal structure over Durban, South Africa (29.9ºS, 31.0ºE) using the Durban Rayleigh Light Detection and Ranging (LIDAR) data collected over 277 nights from April 1999 to July 2004, including closest overpasses of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) and Halogen Occultation Experiments (HALOE) satellites, are presented in this paper. There seems to be good agreement between the LIDAR and satellite observations. During autumn and winter, the temperatures measured by the LIDAR in the height region between 40 km and 55 km were 5 K to 12 K higher than those measured by the satellites. The data from the LIDAR instrument and the SABER and HALOE satellites exhibited the presence of an annual oscillation in the stratosphere, whereas in the mesosphere, semi-annual oscillations dominated the annual oscillation at some levels. The stratopause was observed in the height range of ~40 km - 55 km by all the instruments, with the stratopause temperatures measured as 260 K - 270 K by the LIDAR, 250 K - 260 K by the SABER and 250 K - 270 K by the HALOE. Data from the SABER and HALOE satellites indicated almost the same thermal structure for the middle atmosphere over Durban. <![CDATA[<b><i>Nyctereutes terblanchei</i></b>: <b>the raccoon dog that never was</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100016&lng=en&nrm=iso&tlng=en Fossils of the raccoon dog (genus Nyctereutes) are particularly rare in the African Plio-Pleistocene record, whilst the sole living representative, Nyctereutes procyonoides, is found in eastern Asia and parts of Europe. In southern Africa, only one fossil species of raccoon dog has been identified - Nyctereutes terblanchei. N. terblanchei is recognised from a handful of Plio-Pleistocene sites in South Africa: Kromdraai, Kromdraai-Coopers and Sterkfontein in Gauteng, as well as Elandsfontein in the Western Cape Province. The validity of this species identification was questioned on the basis of the rarity of southern African fossils assigned to Nyctereutes, that is, fewer than 10 specimens have been identified as Nyctereutes. This study examined this fossil sample of the raccoon dog from the Gauteng sites and compared dental and cranial metrics of the fossil with samples of modern canids and published data. Morphological traits used to distinguish Nyctereutes, such as the pronounced subangular lobe on the mandible and the relatively large size of the lower molars, were observed to be variable in all samples. Analysis showed that the size of the dentition of the southern African fossil samples was larger than that of living raccoon dogs, but fell well within the range of that of African jackals. These results suggest that fossil Nyctereutes cannot be distinguished from other canid species based on metric data alone, and may only be diagnosable using combinations of non-metric traits of the dentition and skull. However, based on the degree of morphological variability of the traits used to diagnose Nyctereutes, as well as the rarity of this genus in the African fossil record, these fossils are more likely to belong to a species of jackal or fox. <![CDATA[<b>Canteen Kopje</b>: <b>a new look at an old skull</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100017&lng=en&nrm=iso&tlng=en The Canteen Kopje (CK) skull was found by a diamond digger working the Vaal River gravels in 1929. It was hailed by Robert Broom as an exceptionally robust prehistoric individual that was ancestral to modern South African populations. Further exploration of the Vaal Gravels has confirmed the antiquity of the purported find locality, but the heavily restored CK cranium offers limited possibilities for morphometric re-examination or direct dating with which to test Broom's assertion. We used X-ray tomography to create a computerised 3D image that would provide optimal visualisation of the morphometry of the bony surfaces. The results showed that the CK cranium falls within the range of variation of Holocene Khoesan and lacks archaic features. We propose that it was probably a Late Stone Age intrusion into the Vaal Gravels or the overlying Hutton Sands. <![CDATA[<b>The first animals</b>: <b>ca. 760-million-year-old sponge-like fossils from Namibia</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100018&lng=en&nrm=iso&tlng=en One of the most profound events in biospheric evolution was the emergence of animals, which is thought to have occurred some 600-650 Ma. Here we report on the discovery of phosphatised body fossils that we interpret as ancient sponge-like fossils and term them Otavia antiqua gen. et sp. nov. The fossils are found in Namibia in rocks that range in age between about 760 Ma and 550 Ma. This age places the advent of animals some 100 to 150 million years earlier than proposed, and prior to the extreme climatic changes and postulated stepwise increases in oxygen levels of Ediacaran time. These findings support the predictions based on genetic sequencing and inferences drawn from biomarkers that the first animals were sponges. Further, the deposition and burial of Otavia as sedimentary particles may have driven the large positive C-isotopic excursions and increases in oxygen levels that have been inferred for Neoproterozoic time. <![CDATA[<b>Environmental impacts of electric vehicles in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100019&lng=en&nrm=iso&tlng=en Electric vehicles have been seen by some policymakers as a tool to target reductions in greenhouse gas emissions.1,2 Some researchers have shown that the full environmental impact of electric vehicles depends very much on the cleanliness of the electricity grid.³ In countries such as the USA and China, where coal-fired power plants still play a very important role in electricity generation, the environmental impact of electric vehicles is equivalent to, or even higher than that of cars running on internal combustion engines.4,5 In this study, the environmental impacts of electric vehicles in South Africa were investigated. We found that, as the bulk of South Africa's electricity is generated from relatively low-quality coal and the advanced exhaust clean up technologies are not implemented in the current coal-fired power plants, the use of electric vehicles in South Africa would not help to cut greenhouse gas emissions now (2010) or in the future (in 2030 using the IRP 2010 Revision 2, policy-adjusted IRP scenario), and actually would lead to higher SOx and NOx emissions. <![CDATA[<b>Comparison of the mineral composition of leaves and infusions of traditional and herbal teas</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100020&lng=en&nrm=iso&tlng=en Most research on teas has focused on organic composition and less attention has been given to the mineral composition. The aim of this study was to examine and compare the mineral compositions (Na, Mg, K, Ca, P, S, Fe, Mn, Zn, Cu and Al) of eight commonly consumed teas. The teas included three traditional black or green teas (from Africa, China and Sri Lanka) and five herbal teas - two from South America (maté and coca) and three from South Africa (rooibos, honeybush and Athrixia phylicoides). Analyses were conducted on five samples of dry tea leaves of each of the teas and their infusions (steeping time: 6 min) using identical techniques in inductively coupled plasma optical emission spectrometry (ICP-OES). It was found that each tea has a unique mineral profile. Dry tea leaves and their respective infusions also exhibited different mineral profiles. The tea infusions that contained relatively higher concentrations of beneficial minerals were maté, coca and Athrixia. High levels of aluminium were found in the traditional black and green teas whilst rooibos was high in sodium. Although teas are not rich sources of nutrients, the consumption of maté could contribute significantly to dietary manganese requirements. <![CDATA[<b>On the discontinuous nature of the Mozambique Current</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100021&lng=en&nrm=iso&tlng=en The concept of a spatially continuous western boundary current in the Mozambique Channel has historically been based on erroneous interpretations of ships' drift. Recent observations have demonstrated that the circulation in the Channel is instead dominated by anti-cyclonic eddies drifting poleward. It has therefore been suggested that no coherent Mozambique Current exists at any time. However, satellite and other observations indicate that a continuous current - not necessarily an inherent part of Mozambique Eddies - may at times be found along the full Mozambican shelf break. Using a high-resolution, numerical model we have demonstrated how such a feature may come about. In the model, a continuous current is a highly irregularly occurring event, occurring about once per year, with an average duration of only 9 days and with a vertical extent of about 800 m. Surface speeds may vary from 0.5 m/s to 1.5 m/s and the volume flux involved is about 10 Sv. The continuous current may occasionally be important for the transport of biota along the continental shelf and slope. <![CDATA[<b>First fungal genome sequence from Africa</b>: <b>a preliminary analysis</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100022&lng=en&nrm=iso&tlng=en Some of the most significant breakthroughs in the biological sciences this century will emerge from the development of next generation sequencing technologies. The ease of availability of DNA sequence made possible through these new technologies has given researchers opportunities to study organisms in a manner that was not possible with Sanger sequencing. Scientists will, therefore, need to embrace genomics, as well as develop and nurture the human capacity to sequence genomes and utilise the 'tsunami' of data that emerge from genome sequencing. In response to these challenges, we sequenced the genome of Fusarium circinatum, a fungal pathogen of pine that causes pitch canker, a disease of great concern to the South African forestry industry. The sequencing work was conducted in South Africa, making F. circinatum the first eukaryotic organism for which the complete genome has been sequenced locally. Here we report on the process that was followed to sequence, assemble and perform a preliminary characterisation of the genome. Furthermore, details of the computer annotation and manual curation of this genome are presented. The F. circinatum genome was found to be nearly 44 million bases in size, which is similar to that of four other Fusarium genomes that have been sequenced elsewhere. The genome contains just over 15 000 open reading frames, which is less than that of the related species, Fusarium oxysporum, but more than that for Fusarium verticillioides. Amongst the various putative gene clusters identified in F. circinatum, those encoding the secondary metabolites fumosin and fusarin appeared to harbour evidence of gene translocation. It is anticipated that similar comparisons of other loci will provide insights into the genetic basis for pathogenicity of the pitch canker pathogen. Perhaps more importantly, this project has engaged a relatively large group of scientists including students in a significant genome project that is certain to provide a platform for growth in this important area of research in the future. <![CDATA[<b>Five <i>Ochna</i> species have high antibacterial activity and more than ten antibacterial compounds</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532012000100023&lng=en&nrm=iso&tlng=en New measures to control infections in humans and other animals are continuously being sought because of the increasing resistance of bacteria to antibiotics. In a wide tree screening survey of the antimicrobial activity of extracts of tree leaves (www.up.ac.za/phyto), Ochna pulchra, a small tree found widely in southern Africa, had good antibacterial activity. We therefore investigated the antibacterial activity of acetone leaf extracts of some other available Ochna spp. Antibacterial activity and the number of antibacterial compounds in acetone leaf extracts of Ochna natalitia, Ochna pretoriensis, O. pulchra, Ochna gamostigmata and Ochna serullata were determined with a tetrazolium violet serial microplate dilution assay and bioautography against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa, bacteria commonly associated with nosocomial infections. The percentage yields of the extracts varied from 2.5% to 8%. The minimum inhibitory concentrations of the five species ranged from 40 µg/mL to 1250 µg/mL. E. coli was sensitive to all the extracts. The O. pretoriensis extract was the most active with minimum inhibitory concentrations of 0.065 mg/mL and 0.039 mg/mL against E. coli and E. faecalis, respectively. The O. pretoriensis extract also had the highest total activities of 923 mL/g and 1538 mL/g, indicating that the acetone extract from 1 g of dried plant material could be diluted to 923 mL or 1538 mL and would still kill these bacteria. Based on the bioautography results, the two most active species, O. pretoriensis and O. pulchra, contained at least 10 antibacterial compounds with similar Rf values. Some of these antibacterial compounds were polar and others were non-polar. Variation in the chemical composition of the species may have some taxonomic value. The order of activity of the species to the bacteria were O. pretoriensis > O. pulchra > O. gamostigmata > O. serullata > O. natalitia. Even before toxicity and bioavailability issues are considered, some Ochna spp. leaf extracts have the potential to be used in treating skin infections.