Scielo RSS <![CDATA[South African Journal of Science]]> vol. 109 num. 7-8 lang. es <![CDATA[SciELO Logo]]> <![CDATA[<b>DORA</b>: <b>The San Francisco Declaration on Research Assessment</b>]]> <![CDATA[<b>JEAI-MOCAs</b>: <b>A multi-institutional initiative to build marine research capacity in Mozambique</b>]]> <![CDATA[<b>Reflecting on being ready to go to war</b>]]> <![CDATA[<b>Updated guide to southern Africa's fern flora</b>]]> <![CDATA[<b>Guide to tracks & signs of wildlife</b>: <b>An update</b>]]> <![CDATA[<b>Life and the environment</b>]]> <![CDATA[<b>Science education</b>: <b>The urgent need for critical reflection</b>]]> <![CDATA[<b>Rea Vaya</b>: <b>South Africa's first bus rapid transit system</b>]]> <![CDATA[<b>Random time-activity budgets in captive Southern Ground Hornbill <i>Bucorvus leadbeateri</i></b>]]> <![CDATA[<b>Early science with the Karoo Array Telescope test array KAT-7</b>]]> <![CDATA[<b>Mind the gap</b>: <b>Science and engineering education at the secondary-tertiary interface</b>]]> In the South African higher education sector, there is increasing concern about the poor retention and throughput rates of undergraduate students. There is also concern that the participation rates in higher education, relative to population demographics, remain extremely racially skewed. With the quality of schooling unlikely to change dramatically in the short term, universities need to look for ways to improve student success, particularly in science and engineering, where graduates are needed for a range of key roles in society. Here we review the research presented at a forum held by the Academy of Science of South Africa in 2010, which sought to bring together the latest expert thinking in this area. The major focus of academic development to date has been the establishment of extended degree programmes. However, it is clear that this model has limited capacity to deal with what is, in fact, a much broader problem. We summarise existing interventions aimed at reducing the 'gap' between secondary and tertiary education, and describe key innovations in mainstream programmes that are possible at the levels of pedagogy, curriculum and institutional environment, some of which are also becoming established internationally in science and engineering. Driving such initiatives will demand visionary university leadership in order to effect the integrated and holistic change that is needed. <![CDATA[<b>International positioning of South African electricity prices and commodity differentiated pricing</b>]]> The South African electricity industry has seen a dramatic increase in prices over the past 3 years. This increase has been blanketed across all sectors and is based on a number of factors such as sector, usage and, in the case of domestic pricing, suburb. The cost of electricity in South Africa, particularly to the industrial sector, has been among the lowest in the world. In this paper, we analyse the recent price increases in the South African electricity sector and discuss the price determination mechanism employed by Eskom, South Africa's electricity provider. We also analyse the revenue and sales of Eskom and review the electricity price from an international perspective. The concept of differential pricing and international benchmarking is analysed as a possibility for the South African industrial electricity industry, so that all sectors are not adversely affected by across-the-board increases. Our aim is to raise the question of whether South Africa's electricity prices are in line with international increases and to suggest the possibility of differentiated prices in the local electricity sector. <![CDATA[<b>Exposure to CCA-treated wood amongst food caterers and residents in informal areas of Cape Town</b>]]> We investigated the absorption of chromium, copper and arsenic released from treated wood used by street food caterers and household residents in an informal urban area and a peri-urban area in Cape Town, South Africa. Participants (n=78) selected included an equal number of caterers and residents in each area. All participants answered an exposure questionnaire and were tested for urinary chromium, copper and arsenic, while the urine of 29 participants was also tested for toxic arsenic. Urinary chromium and arsenic exceeded the environmental exposure limit in 12% and 30% of participants, respectively. Toxic arsenic was detected in 30% of samples of which 24% exceeded the environmental exposure limit of 6.4 µg/g creatinine. Urinary chromium, copper, arsenic and toxic arsenic levels were not significantly different between participants from the two areas or between caterers and household residents, controlling for confounding effects. The study provides evidence of chromium and arsenic exposure amongst both informal caterers and household residents, which requires further investigation. <![CDATA[<b>Habitat preferences and movement of adult yellowfishes in the Vaal River, South Africa</b>]]> The yellowfishes of the Vaal River (Labeobarbus kimberleyensis and L. aeneus) are charismatic, socially and economically important fishes, but very little is known about their interspecies habitat preferences and movement. This study is the first behavioural study of yellowfish in the Vaal River using radio transmitters to characterise habitat preferences and movement patterns. A total of 22 adult L. kimberleyensis and 13 adult L. aeneus individuals were tracked for between 1 month and 1 year from 23 September 2006 to 16 May 2010. Radio telemetry revealed that yellowfish established routine daily behavioural patterns through which the habitat preferences and movement of the species could be established. Home ranges of the yellowfish ranged from 1 km to more than 12 km in the Vaal River depending on the species and habitat availability. Habitat preferences varied between species and included deep slow-flowing habitats with associated cover features particularly in winter for L. kimberleyensis and shallow fast-flowing habitats particularly for L. aeneus in spring, summer and autumn. Changes in flows, habitat availability and atmospheric pressure affected the movement of yellowfish. The biology and ecology of the yellowfish in the Vaal River is noticeably more complicated and dynamic than previously documented. We recommend that the behavioural ecology of these and other yellowfish populations in the Vaal River should continue to be characterised, and the use of the movement of yellowfish be developed as an indicator of ecosystem change. <![CDATA[<b>Effect of farming activities on seasonal variation of water quality of Bonsma Dam, KwaZulu-Natal</b>]]> Agriculture has both direct and indirect effects on the quality of surface water and groundwater and is among the leading causes of water quality degradation, mainly as a result of the excessive use of agrochemicals. Water samples were collected in a selected catchment area (Bonsma Dam) in KwaZulu-Natal and analysed for physicochemical variables. The concentrations of most of the elements and total dissolved solids, as well as the pH and electrical conductivity values, met the water quality requirements for domestic, agricultural, livestock and aquatic ecosystem uses. However, the inlet streams feeding the dam were found to be eutrophic during the wet season. Analysis of nitrate in the water body of the study area indicated that agricultural applications of manure and fertilisers may be a potential source of nitrate contamination. Most elements were more concentrated in the dam during the wet season. The overall ionic conductivity values were also higher in the wet season, while the pH was lower. The outcome of this work links the concentrations of physicochemical variables to land use, agricultural practice and local geomorphology. Seasonal patterns in the concentration of physicochemical variables occur, as land use, rainfall and farming activities change seasonally, and these concentrations should therefore be determined periodically. <![CDATA[<b>Scientific research in the natural sciences in South Africa</b>: <b>A scientometric study</b>]]> As a leading producer of scientific publications on the African continent, South Africa has made remarkable progress. However, attempts are yet to be made to comprehend the empirical reality of scientific production in South Africa. One way to do this is to analyse specific science disciplines (such as the natural sciences), publication outputs and their features. A bibliometric study was undertaken of the publication trends and patterns of South African researchers in the natural sciences from 1975 to 2005 (choosing selected sample years), using the Thomson Reuters' Web of Knowledge database of selected indexed natural science journals. Characteristics of natural science publications, such as the trends over the years, were revealed as well as the collaborative dimensions involved in the production of scientific papers in these disciplines in South Africa. The connection between collaboration and publication, as well as between collaboration and sectors of authors was evident. The key findings of this study were that authors were based mostly in universities and were collaborative in their research endeavours. In addition, the participation of international collaborators has increased. <![CDATA[<b>A cell viability assay to determine the cytotoxic effects of water contaminated by microbes</b>]]> Many South Africans do not have access to safe drinking water, so they have no alternative but to use water from contaminated sources that poses a health hazard. This poor state of affairs appears to be deteriorating. In order to distinguish safe from unsafe sources, the aim of this study was to adapt the well-known MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay into a simple and efficient method to screen the suitability of drinking water without needing to know the nature of any possible contamination. This modified assay presents an immediate and reliable answer to whether water is potable without recourse to standard chemical and microbiological water-quality tests. The MTT assay was used here for the first time to test the effects of microbes, and not chemical contaminants as is traditionally the case, on the viability of human duodenum cells exposed to water samples of interest. Filtered tap water and water from a borehole, for example, had limited adverse effects on cell viability. Cell viability decreased greatly after exposure to dam, treated sewage and river water which confirmed the value of the assay as a screening tool. <![CDATA[<b>Participants as community-based peer educators</b>: <b>Impact on a clinical trial site in KwaZulu-Natal</b>]]> Participant recruitment, retention and product adherence are necessary to measure the efficacy or effectiveness of an intervention in a clinical trial. As part of a Phase III HIV prevention trial in a rural area in Kwazulu-Natal, South Africa, a peer educator programme was initiated to aid in recruitment and retention of trial participants from the community. Enrolled trial participants who had completed at least 6 months of trial participation and who had honoured all of their scheduled trial visits within that period were approached to be peer educators. Following additional selection criteria, 24 participants were eligible to be trained as peer educators. Training topics included HIV/AIDS, sexually transmitted infections, nutrition, antiretrovirals, clinical trials, and methods of disseminating this information to the community. The role of peer educators was to bring interested women from their community to the trial site for comprehensive education and information about the trial and possibly trial participation. A total of 1879 women were educated by peer educators between July 2004 and December 2006. Of these, 553 women visited the trial site for further education and screening for participation in the trial. Peer educators provided continuous education and support to women enrolled in the trial which also promoted retention, ultimately contributing to the site's 94% retention rate. Recruitment and retention efforts of trial participants are likely to be enhanced by involving trial participants as peer educators. Such trial participants are in a better position to understand cultural dynamics and hence capable of engaging the community with appropriate HIV prevention and trial-related messaging. <![CDATA[<b>Cellular and molecular effects of electromagnetic radiation and sonic waves</b>]]> Electromagnetic radiation (in the form of pulsed magnetic fields, radiofrequency and intense pulsed light) and mechanical agents (such as sonic waves) have been used in physical therapy. The aim of this study was to assess the effects of low-intensity magnetic fields, sonic and radiofrequency waves, and intense pulsed light on the survival of Escherichia coli cultures and on the electrophoretic mobility of plasmid DNA. Exponentially growing E. coli AB1157 cultures and plasmid DNA samples were exposed to these physical agents and 0.9% NaCl (negative control) and SnCl2 (positive control) solutions. Aliquots of the cultures were diluted and spread onto a solidified rich medium. The colony-forming units were counted after overnight incubation and the survival fraction was calculated. Agarose gel electrophoresis was performed to visualise and quantify the plasmid topological forms. The results suggest that these agents do not alter the survival of E. coli cells or plasmid DNA electrophoresis mobility. Moreover, they do not protect against the lesive action of SnCl2. These physical agents therefore had no cytotoxic or genotoxic effects under the conditions studied. <![CDATA[<b>Degradation of terephthalic acid by a newly isolated strain of <i>Arthrobacter</i> sp.0574</b>]]> Terephthalic acid is an important industrial chemical but its production typically generates 3-10 tons of wastewater, which is a significant source of pollution. Although recent research has shown that terephthalic acid can be degraded by physical and chemical methods, these methods are complex and expensive. Microbial degradation of terephthalic acid is a popular alternative because it is environmentally friendly. We isolated a Gram-positive strain capable of growing aerobically on terephthalic acid as the sole carbon and energy source. It was identified as Arthrobacter sp. by 16S rDNA sequencing and its physiological and biochemical characteristics. For terephthalic acid degradation, the optimal temperature of the resting cells was 30 °C, optimal shaking speed was 150 rpm, the most suitable pH was 7.0, and the ability to degrade terephthalic acid was inhibited by concentrations of terephthalic acid above 10 g/L.