Scielo RSS <![CDATA[South African Journal of Science]]> http://www.scielo.org.za/rss.php?pid=0038-235320140002&lang=pt vol. 110 num. 3-4 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Changes in the offing</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200001&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>A rainbow, prophets and the vortex: The state of South Africa, <i>circa</i> 2012-2013</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200002&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>First complete account of the genus <i>Lachenalia</i> published</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200003&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Taking up the challenge of implementing higher education <i>for</i> the public good</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200004&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Is the Equity Index a good tool to gauge demographic transformation at South African universities?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200005&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Value measurement theory and league tables</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200006&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>The contribution of higher education institutions to the South African economy</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200007&lng=pt&nrm=iso&tlng=pt We present the direct and indirect contributions of higher education institutions in South Africa to certain macroeconomic indicators such as GDP and employment, with the ultimate purpose of establishing their importance for the country. Taking this a step further, funding of these institutions is crucial in order for them to continuously produce outcomes in terms of research and skilled graduates. Hence, we compare the South African research and development (R&D) expenditure with international best practice. Policy implications are also discussed, especially in the light of the new funding formula for universities to be announced by the Department of Higher Education and Training. <![CDATA[<b>Elephants in Africa</b>: <b>Big, grey biodiversity thieves?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200008&lng=pt&nrm=iso&tlng=pt We present the direct and indirect contributions of higher education institutions in South Africa to certain macroeconomic indicators such as GDP and employment, with the ultimate purpose of establishing their importance for the country. Taking this a step further, funding of these institutions is crucial in order for them to continuously produce outcomes in terms of research and skilled graduates. Hence, we compare the South African research and development (R&D) expenditure with international best practice. Policy implications are also discussed, especially in the light of the new funding formula for universities to be announced by the Department of Higher Education and Training. <![CDATA[<b>Taking the transformation discourse forward</b>: <b>A response to Cloete, Dunne and Moultrie and Dorrington</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200009&lng=pt&nrm=iso&tlng=pt We present the direct and indirect contributions of higher education institutions in South Africa to certain macroeconomic indicators such as GDP and employment, with the ultimate purpose of establishing their importance for the country. Taking this a step further, funding of these institutions is crucial in order for them to continuously produce outcomes in terms of research and skilled graduates. Hence, we compare the South African research and development (R&D) expenditure with international best practice. Policy implications are also discussed, especially in the light of the new funding formula for universities to be announced by the Department of Higher Education and Training. <![CDATA[<b>Greenhouse gas emissions from shale gas and coal for electricity generation in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200010&lng=pt&nrm=iso&tlng=pt There is increased interest, both in South Africa and globally, in the use of shale gas for electricity and energy supply. The exploitation of shale gas is, however, not without controversy, because of the reported environmental impacts associated with its extraction. The focus of this article is on the greenhouse gas footprint of shale gas, which some literature suggests may be higher than what would have been expected as a consequence of the contribution of fugitive emissions during extraction, processing and transport. Based on some studies, it has been suggested that life-cycle emissions may be higher than those from coal-fired power. Here we review a number of studies and analyse the data to provide a view of the likely greenhouse gas emissions from producing electricity from shale gas, and compare these emissions to those of coal-fired power in South Africa. Consideration was given to critical assumptions that determine the relative performance of the two sources of feedstock for generating electricity - that is the global warming potential of methane and the extent of fugitive emissions. The present analysis suggests that a 100-year time horizon is appropriate in analysis related to climate change, over which period the relative contribution is lower than for shorter periods. The purpose is to limit temperature increase in the long term and the choice of metric should be appropriate. The analysis indicates that, regardless of the assumptions about fugitive emissions and the period over which global warming potential is assessed, shale gas has lower greenhouse gas emissions per MWh of electricity generated than coal. Depending on various factors, electricity from shale gas would have a specific emissions intensity between 0.3 tCO2/MWh and 0.6 tCO2/MWh, compared with about 1 tCO,/MWh for coal-fired electricity in South Africa. <![CDATA[<b>Postgraduate research methodological flaws detected at final examination stage</b>: <b>Who is to blame?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200011&lng=pt&nrm=iso&tlng=pt In the wake of globalisation, most universities are intensifying efforts to improve their overall performance in order to attract students and enhance chances of securing competitive funding from various sources. As part of these efforts, universities are striving to ensure that their postgraduate programmes meet nationally and internationally acceptable standards. Research projects conducted by students form a critical component of most postgraduate programmes and universities have put in place procedures meant to ensure that postgraduate research meets acceptable minimum standards. The procedures include setting minimum entry educational qualifications, supervision by qualified members of university academic staff, institutional evaluation of research proposals before the proposed research is embarked on, submission of progress reports by postgraduate students during the course of their programmes, and final examination of students' theses, dissertations or research reports by internal as well as external examiners. In some instances, the examiners recommend outright rejection of the student's write-up if they consider the methodology used to be inappropriate to answer research questions of the project conducted. The implications of research methodological shortcomings which are identified at the final examination stage, even if the research proposals were evaluated and approved by appropriate university structures before commencement of the research projects, are discussed. As postgraduate programmes are meant to nurture a competent and resourceful workforce and future researchers, universities need to pay attention to the issue of research methodology and internal evaluation systems in order to minimise chances of compromising the quality of their postgraduate degree programmes. <![CDATA[<b>Engine emissions and combustion analysis of biodiesel from East African countries</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200012&lng=pt&nrm=iso&tlng=pt Environmental, availability and financial problems associated with fossil fuels encourage the manufacture and use of biodiesel. In this study, vegetable oil was extracted from Jatropha curcas seeds sourced from Kenya and Tanzania. A two-step acid-base catalytic transesterification process was used to produce biodiesel because of the amount of free fatty acids present in the oil. The test rig used in the experiments was an Audi, 1.9-litre, turbocharged direct injection, compression ignition engine. Emissions were measured using an Horiba emission analyser system while combustion data was collected by a data acquisition system, from which cylinder pressure and rate of heat release of the test engine in every crank angle were calculated. The two biodiesels showed better emission characteristics than the fossil diesel included in the tests for comparison purposes. Cylinder pressure and heat release of the biodiesel were also within acceptable ranges. However, the emission and combustion characteristics differed between the two biodiesels - a result likely related to their different origins. These findings prove that the source of biodiesel is an important factor to consider. <![CDATA[<b>Impact of lower stratospheric ozone on seasonal prediction systems</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200013&lng=pt&nrm=iso&tlng=pt We conducted a comparison of trends in lower stratospheric temperatures and summer zonal wind fields based on 27 years of reanalysis data and output from hindcast simulations using a coupled ocean-atmospheric general circulation model (OAGCM). Lower stratospheric ozone in the OAGCM was relaxed to the observed climatology and increasing greenhouse gas concentrations were neglected. In the reanalysis, lower stratospheric ozone fields were better represented than in the OAGCM. The spring lower stratospheric/ upper tropospheric cooling in the polar cap observed in the reanalysis, which is caused by a direct ozone depletion in the past two decades and is in agreement with previous studies, did not appear in the OAGCM. The corresponding summer tropospheric response also differed between data sets. In the reanalysis, a statistically significant poleward trend of the summer jet position was found, whereas no such trend was found in the OAGCM. Furthermore, the jet position in the reanalysis exhibited larger interannual variability than that in the OAGCM. We conclude that these differences are caused by the absence of long-term lower stratospheric ozone changes in the OAGCM. Improper representation or non-inclusion of such ozone variability in a prediction model could adversely affect the accuracy of the predictability of summer rainfall forecasts over South Africa. <![CDATA[<b>Flood variation and soil nutrient content in floodplain vegetation communities in the Okavango Delta</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200014&lng=pt&nrm=iso&tlng=pt We investigated the influence of hydroperiod variation on soil nutrient content in the Okavango Delta seasonal floodplains. Soil samples were collected from eight zones of homogenous vegetation cover after low and high floods and analysed for pH, Na, Mg, Ca, K and P content. A Student's t-test was used to test for differences in pH, Na, Mg, Ca, K and P between soils after low and high floods. The Kruskal-Wallis test was used to compare means of flooding duration and depth between low and high floods. Na, K, Mg, P and pH levels in soils were significantly different (p<0.05) after low floods compared with after high floods. Na content was lower (p<0.05) in Zones 2 and 8 and higher (p<0.05) in Zones 4, 5 and 6 during high flood than during low flood. Ca content was lower (p<0.05) in Zones 1, 2, 3, 4 and 5 and higher in Zone 7 (p<0.05) under high flood than during low flood. Mg content was lower (p<0.05) in Zones 1 and 5 and higher (p<0.05) in Zones 6, 7 and 8 during high flood than during low flood. K content was lower in Zones 1 and 3 and lower in Zones 6, 7 and 8 (p<0.05) during high flood than during low flood. pH was significantly lower and higher after a high flood in Zones 1 and 6, respectively, than during low flood. P content was significantly (p<0.05) higher in all zones after high flood than after low flood. Flooding depth and duration increased (p<0.05) in all vegetation zones during high flood. Our results have direct implications for molapo (flood recession) farming. We recommend that farmers plough immediately after the onset of flood recession when the soil is still moist and rich in nutrients. <![CDATA[<b>Assessment of atmospheric trace metals in the western Bushveld Igneous Complex, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200015&lng=pt&nrm=iso&tlng=pt Trace metal species emitted into the atmosphere from natural and anthropogenic sources can cause various health-related and environmental problems. Limited data exist for atmospheric trace metal concentrations in South Africa, which has the largest industrialised economy in Africa, with significant mining and metallurgical activities. A large fraction of these mineral assets is concentrated in the Bushveld Igneous Complex, with the western limb being the most exploited. To partially address this knowledge gap, atmospheric trace metals were collected in the western Bushveld Igneous Complex at Marikana in the North West Province. Diurnal PM25 and PM10 samples were collected for 1 year. A total of 27 trace metal species were determined. With the exception of Ni, none of the trace metals measured during the sampling period exceeded local or international air quality standard limit values. Total trace metal concentrations in the PM10 fraction peaked during the dry months and were regularly washed out during the wet season. A less significant seasonal trend was observed for the trace metal concentrations in the PM2.5 fraction; a finding attributed to a faster replenishment of smaller particles into the atmosphere after rain events. About 80% of the PM10 trace metal levels measured occurred in the PM2.5 fraction, while 40% or more of all metals emanated from the PM2.5 fraction. This finding indicated a strong influence of anthropogenic sources. Four meaningful emission sources were determined from explorative principal component factor analysis: crustal, vanadium related, base metal related and ferrochromium related, which correlated well with the anticipated atmospheric trace metal sources in the region. <![CDATA[<b>High biomass yielding winter cover crops can improve phosphorus availability in soil</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200016&lng=pt&nrm=iso&tlng=pt We investigated the effects of high biomass yielding winter cover crops, namely grazing vetch [Vicia dasycarpa L.) and oats [Avena sativa L.), on soil phosphorus (P) availability in low fertiliser input maize-based conservation agriculture systems. Soil samples were collected from the 0-50-mm depth of experimental plots after 4 years of maize-winter cover crop rotations. A sequential fractionation scheme was used to separate total soil P into labile, moderately labile and non-labile organic P (Po) and inorganic (Pi) pools. Labile P pools included microbial biomass-P as well as Pi and Po pools extracted using 0.5 M NaHCO3 and 1.0 M HCl. The non-labile P pools were humic-P and 1.0 M H2SO4 extracted P Soil on the maize-winter cover crop rotations had higher HCl-Pi and total P than the soil on the maize-fallow rotation. The cover crops had no significant (p>0.05) effect on NaHCO3-Po, NaHCO3-Pi, HCl-Po, fulvic acid-P and recalcitrant H2SO4-P fractions. Non-application of fertiliser increased accumulation of humic-P on the maize-oats rotation. Cover crop biomass input explained 73% of the variations in microbial biomass-P and 33% of variations in total labile P. Phosphorus concentration of young maize plants was significantly increased by the cover crops, with a positive correlation to HCl-Pi (r s=0.90). This contribution from winter cover crops to P availability in the surface soil suggests that, in the long term, fertiliser P could be reduced in such systems. <![CDATA[<b>An evaluation for harnessing low-enthalpy geothermal energy in the Limpopo Province, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200017&lng=pt&nrm=iso&tlng=pt South Africa generates most of its energy requirements from coal, and is now the leading carbon emitter in Africa, and has one of the highest rates of emissions of all nations in the world. In an attempt to decrease its CO2 emissions, South Africa continues to research and develop alternative forms of energy, expand on the development of nuclear and has began to explore potentially vast shale gas reserves. In this mix, geothermal has not been considered to date as an alternative energy source. This omission appears to stem largely from the popular belief that South Africa is tectonically too stable. In this study, we investigated low-enthalpy geothermal energy from one of a number of anomalously elevated heat flow regions in South Africa. Here, we consider a 75-MW enhanced geothermal systems plant in the Limpopo Province, sustainable over a 30-year period. All parameters were inculcated within a levelised cost of electricity model that calculates the single unit cost of electricity and tests its viability and potential impact toward South Africa's future energy security and CO2 reduction. The cost of electricity produced is estimated at 14 USc/KWh, almost double that of coal-generated energy. However, a USD25/MWh renewable energy tax incentive has the potential of making enhanced geothermal systems comparable with other renewable energy sources. It also has the potential of CO2 mitigation by up to 1.5 gCO,/KWh. Considering the aggressive nature of the global climate change combat and South Africa's need for a larger renewable energy base, low-enthalpy geothermal energy could potentially form another energy option in South Africa's alternative energy basket. <![CDATA[<b>Palaeomagnetic and synchrotron analysis of >1.95 Ma fossil-bearing palaeokarst at Haasgat, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200018&lng=pt&nrm=iso&tlng=pt Palaeomagnetic analysis indicates that Haasgat, a fossil-bearing palaeocave in the Gauteng Province of South Africa, is dominated by reversed magnetic polarity in its oldest, deepest layers and normal polarity in the younger layers. The presence of in-situ Equus specimens suggests an age of less than ~2.3 Ma, while morphological analysis of faunal specimens from the ex-situ assemblage suggests an age greater than 1.8 Ma. Given this faunal age constraint, the older reversed polarity sections most likely date to the beginning of the Matuyama Chron (2.58-1.95 Ma), while the younger normal polarity deposits likely date to the very beginning of the Olduvai Sub-Chron (1.95-1.78 Ma). The occurrence of a magnetic reversal from reversed to normal polarity recorded in the sequence indicates the deposits of the Bridge Section date to ~1.95 Ma. All the in-situ fossil deposits that have been noted are older than the 1.95 Ma reversal, but younger than 2.3 Ma. Haasgat therefore dates to an interesting time period in South African human evolution that saw the last occurrence of two australopith species at ~2.05-2.02 Ma (Sts5 Australopithecus africanus from Sterkfontein Member 4) to ~1.98 Ma (Australopithecus sediba from Malapa) and the first occurrence of early Homo (Sk847), Paranthropus and the Oldowan within Swartkrans Member 1 between ~2.0 Ma and ~1.8 Ma. <![CDATA[<b>Predicting scientific research output at the University of KwaZulu-Natal</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532014000200019&lng=pt&nrm=iso&tlng=pt Academic members of staff at the University of KwaZulu-Natal (UKZN) are expected to publish in research journals that have been accredited by the South African based Department of Higher Education and Training. However, some members of staff have chosen to focus solely on the teaching aspect of their careers and as a result they have no publication record. In this study, a set of per annum productivity unit counts was calculated for every academic at UKZN. Because it is possible for a publishing academic to also record a zero count for a given year, it is necessary to develop an appropriate methodology that can distinguish this zero count from one that will always be recorded by a non-publishing academic. By fitting a zero-inflated Poisson model to the data, specific factors can be identified that separately drive the non-publishing and publishing processes at UKZN. In particular, having a PhD and working in a large school has a significant impact on improving the research output of a publishing academic. If UKZN wants to become a research-focused university, non-publishing academics should be encouraged to undertake a PhD degree.