Scielo RSS <![CDATA[South African Journal of Science]]> http://www.scielo.org.za/rss.php?pid=0038-235320100003&lang=en vol. 106 num. 5-6 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>The centenary of Union</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300001&lng=en&nrm=iso&tlng=en <![CDATA[<b>Pebble bed modular reactor demonstration plant is funded but not constructed</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300002&lng=en&nrm=iso&tlng=en <![CDATA[<b>Commentary on the African Biological Safety Association inaugural meeting</b>: <b>8-12 March 2010</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300003&lng=en&nrm=iso&tlng=en <![CDATA[<b>The deep-time treasure chest of the Makhonjwa Mountains</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300004&lng=en&nrm=iso&tlng=en <![CDATA[<b>Can lizards beat the heat, or will they go extinct?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300005&lng=en&nrm=iso&tlng=en <![CDATA[<b>Union by default?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300006&lng=en&nrm=iso&tlng=en <![CDATA[<b>Fires, science and society</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300007&lng=en&nrm=iso&tlng=en <![CDATA[<b>Fording the Amazon</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300008&lng=en&nrm=iso&tlng=en <![CDATA[<b>Frederik van Zyl Slabbert (1940-2010)</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300009&lng=en&nrm=iso&tlng=en <![CDATA[<b>Evidence-based policymaking</b>: <b>a review</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300010&lng=en&nrm=iso&tlng=en The process of facilitating the uptake of evidence, for example, scientific research findings, into the policymaking process is multifaceted and thus complex. It is therefore important for scientists to understand this process in order to influence it more effectively. Similarly, policymakers need to understand the complexities of the scientific process to improve their interaction with the scientific sphere. This literature review addresses those factors that influence the uptake of scientific evidence into policymaking, the barriers to using science in policymaking, as well as recommendations for improved science-policymaking interaction. A visual diagram of the gears of a car is used to convey the message of the complexities around the engagement between science and policymaking. It is concluded that the issue of evidence-based policymaking remains unresolved and questions for future research on the science-policy interface are raised. <![CDATA[<b>The enterprise ecology of towns in the Karoo, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300011&lng=en&nrm=iso&tlng=en Two concepts, (1) companies are 'living' entities and (2) 'company ecology', stimulated our hypothesis that towns are 'enterprise ecosystems'. This hypothesis cannot be tested directly. However, if it is correct, application of clustering and ordination techniques used frequently in studies of natural ecosystems, should reveal clusters of towns that are statistically significantly different (p < 0.05). A dataset of 47 towns in the Karoo, South Africa served as study material and their enterprise assemblages were profiled through the use of a simple method based on the examination of telephone directories. Clustering and ordination techniques revealed six different clusters of towns at a correlation coefficient level of 0.65 and the clusters differed significantly (p < 0.05) in some respects. The agricultural products and services, the tourism and hospitality, and the trade sectors were particularly important in defining these clusters. We concluded that enterprise ecology is a valid concept and towns are 'ecosystems' that also cluster together in larger groupings. An array of potentially important techniques and approaches for the study of business development in towns now provide support to, and intriguing questions confront, academic and practical researchers of enterprise development in towns. <![CDATA[<b>An assessment of the atmospheric nitrogen budget on the South African Highveld</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300012&lng=en&nrm=iso&tlng=en Atmospheric reactive nitrogen concentrations on the South African Highveld have become a growing concern, with satellite images indicating very high nitrogen dioxide (NO2) concentrations in the region. This study investigated the nitrogen budget on the Highveld through the analysis of the concentration of the atmospheric nitrogen species on a temporal scale as well as the atmospheric conversion, transport and removal of these species. Data were collected at Eskom's Elandsfontein ambient air quality monitoring site, which is centrally located on the industrialised Highveld. A year's dataset from 2005 and 2006 was analysed and it was found that nitrogen oxide (NOx) concentrations were higher in winter as a result of stable atmospheric conditions, as well as prevalent westerly and north-westerly airflow, which transported emissions directly from the nearby power station sources to the monitoring site. Nitrate (NO3) concentrations also peaked during winter, with a distinct biomass burning peak during August 2005. Diurnally, NOx concentrations indicated a tall-stack industrial source, where concentrations peaked at midday. The NO3 concentrations were higher at night than during the day; during the day the NO3 radical is rapidly photolysed and nitrates cannot be produced. Case studies indicated that the conversion rate of nitric oxide (NO) to NO2 was highly variable as a result of varying atmospheric factors, which include time of day, dispersion, stability and regional atmospheric chemistry. These rates ranged from 11% to 59% per hour. Rates of dry deposition of NO, NO2 and NO3 were generally higher during winter as a result of higher atmospheric concentrations and increased atmospheric stability. Nitrogen was predominantly deposited as NO2 throughout the year, except during spring when NO3 deposition dominated. The total annual amount of nitrogen that was deposited to the Mpumalanga Highveld region was in the range of 6.7 kg/ha - 13.1 kg/ha per year, which is well below the stipulated critical load value. Such deposition, therefore, should not pose significant threats to the natural environment on the Highveld. Between 4% and 15% of the total emitted nitrogen from power generation on the Highveld was deposited to the surface via wet and dry deposition. The remainder was advected out of the region. <![CDATA[<b>Bridging the science-policy interface</b>: <b>a new era for South African research and the role of knowledge brokering</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300013&lng=en&nrm=iso&tlng=en Government departments and agencies are faced with issues of increasing socio-ecological complexities around environmental sustainability and global change, which require them to make decisions that have the potential to impact greatly on society and economies. As a result, they are under increasing pressure to develop policies that consider a wide spectrum of scientific and indigenous knowledge. It is acknowledged that in South Africa, as elsewhere, a gap typically exists between the scientific or research community and the policymaking community, due to a number of underlying reasons at both ends. This gap often results in a unidirectional 'push of evidence' by researchers to policymakers, with a hope that policymakers will take up these findings and use them in policy identification, formulation or implementation. To support the uptake of evidence in policy, it is also important to stimulate an environment of 'evidence pull' by the policy community from the research community, as well as increasing the dialogue between these communities. A model of knowledge brokering is proposed in this paper as a means to bridge this gap between science and policy and, thereby, ensure the uptake of evidence in policy development and implementation. This model looks at the need for institutional mechanisms, such as knowledge-brokering offices, both within research organisations and government departments. It also highlights the importance of researchers involving policymakers from the onset of their research process, with a continuous dialogue between the two parties, both during and after the research, as a means of increasing the likelihood of research uptake. <![CDATA[<b>A tool for modernisation?</b><b> </b><b>The Boer concentration camps of the South African War, 1900-1902</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300014&lng=en&nrm=iso&tlng=en While not denying the tragedy of the high mortality of people in the concentration camps in the South African War of 1899-1902, this article suggests that, for Lord Milner and the British Colonial Office, the camps became a means of introducing the rural society of the Boers to the facilities of modern life. To some extent they became, in effect, part of Milner's project for 'civilising' and assimilating the Boers into British colonial society. The high mortality rate was finally contained through the introduction of a modern public health system, including the use of statistics and the employment of qualified doctors and nurses. Young Boer women working in the camp hospitals as nurse aids were trained as 'probationers' and classes in infant and child care were offered to the Boer mothers. In addition, the need for adequate water supplies and effective sanitation meant that an infrastructure was established in the camps that familiarised the Boers with modern sanitary routines and left a legacy of more substantial services for the Transvaal and Orange Free State villages. <![CDATA[<b>Synthesis of zeolite-P from coal fly ash derivative and its utilisation in mine-water remediation</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300015&lng=en&nrm=iso&tlng=en Solid residues resulting from the active treatment of acid mine drainage with coal fly ash were successfully converted to zeolite-P under mild hydrothermal treatment conditions. Scanning electron microscopy showed that the zeolite-P product was highly crystalline. The product had a high cation exchange capacity (178.7 meq / 100 g) and surface area (69.1 m²/g) and has potential application in waste-water treatment. A mineralogical analysis of the final product identified zeolite-P, as well as mullite and quartz phases, which indicated incomplete dissolution of the fly ash feedstock during the ageing step. Further optimisation of the synthesis conditions would be required to attain complete utilisation of the feedstock. The zeolite-P was tested for decontamination potential of circumneutral mine water. High removal efficiency was observed in the first treatment, but varied for different contaminants. The synthesised zeolite-P exhibited a high efficiency for the removal of heavy metal cations, such as aluminium, iron, manganese, zinc, copper and nickel, from contaminated mine water, even with repeated use. For potassium, calcium, strontium and barium, the removal was only efficient in the first treatment and decreased rapidly with subsequent treatments, indicating preferential adsorption of the other metals. A continuous release of sodium was observed during decontamination experiments, which decreased with subsequent treatments, confirming that sodium was the main exchangeable charge-balancing cation present in the zeolite-P product. <![CDATA[<b>PI3K-dependent ERK is involved in GM-CSF-mediated activation of progenitor cells in a neovascularisation model</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300016&lng=en&nrm=iso&tlng=en The current study investigated the effects of the granulocyte-macrophage colony-stimulating factor (GM-CSF) on rat endothelial progenitor cell (EPC) biology. EPCs were isolated from rat bone marrow and experiments were carried out to determine the dose- and time-dependent effects of GM-CSF on angiogenesis, proliferation, viability, migration and vasculogenesis. EPCs were co-cultured with rat cardiac microvascular endothelial cells (CMECs) to determine the effect of GM-CSF on EPC angiogenesis in vitro. EPC proliferation and viability, migration, and vasculogenesis were measured by the respective application of the method of transcription and translation (MTT) assay, the Transwell chamber assay and the Matrigel assay. GM-CSF treatment stimulated EPC angiogenesis, proliferation, viability, migration and tubule formation in a dose- and time-dependent manner. Furthermore, GM-CSF treatment led to the upregulation of integrinβ2, vascular endothelial growth factor (VEGF) and p-extracellular signal-regulated kinase (p-ERK) 1/2 levels in EPCs. Moreover, two different phosphatidylinositol 3-kinase (PI3K) inhibitors (LY294002 and Wortmannin) partially inhibited the GM-CSF-mediated increase in p-ERK1/2 levels in EPCs. The ERK inhibitor, FR180204, dramatically inhibited GM-CSF-mediated stimulation of EPC proliferation, migration and vasculogenesis. Taken together, the results of the current study provide evidence that a PI3K-dependent ERK signalling pathway is, at least, partially responsible for the GM-CSF-mediated effects on EPC function. <![CDATA[<b>Competence of Science Foundation students in some simple strategies for problem solving</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300017&lng=en&nrm=iso&tlng=en The competence of over 300 Science Foundation students in five important problem-solving strategies was studied at the North-West University over a period of three years. The study method adopted was the analysis of students' answers to carefully designed questions that tested whether they competently used the following strategies for problem solving: clarifying problems by presenting them clearly, identifying explicitly the principles and laws associated with the solutions, focusing sharply on the goal, using equations for deductions and calculations and proceeding step-by-step with the solution. The results showed that their competence in the use of intellectual strategies was very poor. This lack of competence could be expected to lead to lack of self-confidence and could also seriously handicap their learning throughout their courses. We suggest that greater emphasis should be placed, in all science courses, on the training of students in intellectual skills and strategies. Such training should be integrated with the teaching of subject content throughout the courses. <![CDATA[<b>Creation of a high-yielding recombinant maize hybrid for the production of a microbicide to prevent HIV-1 transmission</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300018&lng=en&nrm=iso&tlng=en The aim of this study was to use conventional breeding to increase the production in maize of the human monoclonal antibody 2G12, known to have potential therapeutic properties in the prevention of HIV-1 transmission. The recombinant antibody, together with a fluorescent marker, was introduced into two South African high-performing maize elite inbred lines by crossing them with a transgenic maize line that had been transformed with the monoclonal antibody 2G12. The effect of breeding to produce high-expressing recombinant hybrid seed was evaluated by comparing 2G12 production in the different breeding lines with the original maize line. 'Good production practice standards' were followed throughout the breeding programme. 'Conventional drug regulations' adapted to plant-made pharmaceuticals were also followed, with the seeds being stored in a 'master seed bank'. The maize hybrid expressed a higher level of the antibody than the recombinant maize elite lines. This plant-derived antibody provides a means of producing a microbicide component that could be used with other HIV-neutralising antibodies as an additional approach to prevent HIV infection. <![CDATA[<b>Microwave plasma-enhanced chemical vapour deposition growth of carbon nanostructures</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300019&lng=en&nrm=iso&tlng=en The effect of various input parameters on the production of carbon nanostructures using a simple microwave plasma-enhanced chemical vapour deposition technique has been investigated. The technique utilises a conventional microwave oven as the microwave energy source. The developed apparatus is inexpensive and easy to install and is suitable for use as a carbon nanostructure source for potential laboratory-based research of the bulk properties of carbon nanostructures. A result of this investigation is the reproducibility of specific nanostructures with the variation of input parameters, such as carbon-containing precursor and support gas flow rate. It was shown that the yield and quality of the carbon products is directly controlled by input parameters. Transmission electron microscopy and scanning electron microscopy were used to analyse the carbon products; these were found to be amorphous, nanotubes and onion-like nanostructures. <![CDATA[<b>Land-cover classification with an expert classification algorithm using digital aerial photographs</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532010000300020&lng=en&nrm=iso&tlng=en The purpose of this study was to evaluate the usefulness of the spectral information of digital aerial sensors in determining land-cover classification using new digital techniques. The land covers that have been evaluated are the following, (1) bare soil, (2) cereals, including maize (Zea mays L.), oats (Avena sativa L.), rye (Secale cereale L.), wheat (Triticum aestivum L.) and barley (Hordeun vulgare L.), (3) high protein crops, such as peas (Pisum sativum L.) and beans (Vicia faba L.), (4) alfalfa (Medicago sativa L.), (5) woodlands and scrublands, including holly oak (Quercus ilex L.) and common retama (Retama sphaerocarpa L.), (6) urban soil, (7) olive groves (Olea europaea L.) and (8) burnt crop stubble. The best result was obtained using an expert classification algorithm, achieving a reliability rate of 95%. This result showed that the images of digital airborne sensors hold considerable promise for the future in the field of digital classifications because these images contain valuable information that takes advantage of the geometric viewpoint. Moreover, new classification techniques reduce problems encountered using high-resolution images; while reliabilities are achieved that are better than those achieved with traditional methods.