Scielo RSS <![CDATA[South African Journal of Science]]> http://www.scielo.org.za/rss.php?pid=0038-235320170001&lang=es vol. 113 num. 1-2 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>What could scientists do about 'post-truth'?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100001&lng=es&nrm=iso&tlng=es <![CDATA[<b>South Africans pioneer heat transfer technology for conversion of waste to energy</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100002&lng=es&nrm=iso&tlng=es <![CDATA[<b>Survivorship of spekboom (<i>Portulacaria afra</i>) planted within the Subtropical Thicket Restoration Programme</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100003&lng=es&nrm=iso&tlng=es <![CDATA[<b>Marion Island half a century ago: A glimpse into an earlier era of sub-Antarctic exploration</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100004&lng=es&nrm=iso&tlng=es <![CDATA[<b>Creating critical conversations on higher education curricula in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100005&lng=es&nrm=iso&tlng=es <![CDATA[<b>From the NCHE to #FeesMustFall: An incomplete but important story of a difficult journey</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100006&lng=es&nrm=iso&tlng=es <![CDATA[<b>Educational investment towards the ideal future: South Africa's strategic choices</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100007&lng=es&nrm=iso&tlng=es Although there has been rapid expansion of higher education around the globe, such expansion has not resulted in a more equitable system. Drawing on the work of Nancy Fraser, equity in higher education is conceptualised as 'parity of participation' and includes both equity of access and outcomes. The tensions between expansion and equity are illustrated by comparing South Africa's equity challenges with those of Brazil and the USA. Focusing on South Africa's critical choices, four scenarios or possible futures are provided to illustrate some of the trade-offs and strategic choices. The main argument is that if South Africa's higher education system continues to expand without a concomitant investment in the effectiveness of teaching and learning, it will not achieve the policy goals of equity of access and outcomes. Furthermore the investment needs to be strategically targeted to interventions that can serve as systemic levers of change for reducing drop-out rates and improving graduation rates. To this end, over the next decade the state needs to prioritise an investment in an undergraduate curriculum more 'fit for purpose'. The investment needs to be in curriculum reform that normalises different levels of foundational provision, identifies and removes curriculum obstacles that delay or impede graduation, and provides opportunities for 'breadth' for all students, not only those who come from privileged backgrounds. SIGNIFICANCE: • If South Africa's higher education system continues to expand without a concomitant investment in the effectiveness of teaching and learning, it will not achieve the policy goals of equity of access and outcomes. <![CDATA[<b>Estimation of household income diversification in South Africa: A case study of three provinces</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100008&lng=es&nrm=iso&tlng=es We estimated household income diversification in settlement types of the poorest provinces in South Africa - the Eastern Cape, Limpopo and KwaZulu-Natal. We obtained data from the 2010/2011 Income and Expenditure Survey from Statistics South Africa and Wave 3 data from the National Income Dynamics Study. We used the number of income sources, the number of income earners and the Shannon Diversity Index to estimate income diversification in the study provinces. The results show that households in the traditional and urban formal areas diversified income sources to a greater extent than households in urban informal and rural formal settlements. The varied degrees of income diversification in the three provinces suggest that targeted policy initiatives aimed at enhancing household income are important in these provinces. SIGNIFICANCE: • Indices yet to be used in South Africa were used in the analysis of StatsSA data to understand income diversification. • Poverty is mostly concentrated in the traditional areas and urban informal areas. • Households in the traditional areas and urban informal areas derive livelihood mostly from social transfers and remittances, whereas those in the urban formal areas derive income from business, labour income and financial capital returns. <![CDATA[<b>Speech recognition for under-resourced languages: Data sharing in hidden Markov model systems</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100009&lng=es&nrm=iso&tlng=es For purposes of automated speech recognition in under-resourced environments, techniques used to share acoustic data between closely related or similar languages become important. Donor languages with abundant resources can potentially be used to increase the recognition accuracy of speech systems developed in the resource poor target language. The assumption is that adding more data will increase the robustness of the statistical estimations captured by the acoustic models. In this study we investigated data sharing between Afrikaans and Flemish - an under-resourced and well-resourced language, respectively. Our approach was focused on the exploration of model adaptation and refinement techniques associated with hidden Markov model based speech recognition systems to improve the benefit of sharing data. Specifically, we focused on the use of currently available techniques, some possible combinations and the exact utilisation of the techniques during the acoustic model development process. Our findings show that simply using normal approaches to adaptation and refinement does not result in any benefits when adding Flemish data to the Afrikaans training pool. The only observed improvement was achieved when developing acoustic models on all available data but estimating model refinements and adaptations on the target data only. SIGNIFICANCE: • Acoustic modelling for under-resourced languages • Automatic speech recognition for Afrikaans • Data sharing between Flemish and Afrikaans to improve acoustic modelling for Afrikaans <![CDATA[<b>Antifungal actinomycetes associated with the pine bark beetle, <i>Orthotomicus erosus, </i>in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100010&lng=es&nrm=iso&tlng=es Actinomycete bacteria are often associated with insects that have a mutualistic association with fungi. These bacteria are believed to be important to this insect-fungus association as they produce antibiotics that exclude other saprophytic fungi from the immediate environment. The aim of this study was to investigate the presence of potentially protective actinomycetes associated with Orthotomicus erosus, an alien invasive pine bark beetle, in South Africa. This bark beetle and its relatives have an association with Ophiostomatales species which are often the only fungi found in the bark beetle galleries. We hypothesised that antibiotic-producing actinomycetes could be responsible for the paucity of other fungi in the galleries by producing compounds to which the Ophiostoma spp. are tolerant. Several actinomycetes in the genus Streptomyces and one Gordonia sp. were isolated from the beetle. Interestingly, most isolates were from the same species as actinomycetes associated with other pine-infesting insects from other parts of the world, including bark beetles and the woodwasp Sirex noctilio. Most actinomycetes isolated had strong antifungal properties against the selected test fungi, including Ophiostoma ips, which is the most common fungal symbiont of Orthotomicus erosus. Although the actinomycetes did not benefit Ophiostoma ips and the hypothesis was not supported, their sporadic association with Orthotomicus erosus suggests that they could have some impact on the composition of the fungal communities present in the bark beetle galleries, which is at present poorly understood. SIGNIFICANCE: • Discovery of four putative undescribed Streptomyces spp. with antibiotic potential • First record of the introduction of actinomycete bacteria with pine-infesting insects into South Africa • Actinomycetes from South Africa group with undescribed Streptomyces spp. from pine-infesting insects of North America <![CDATA[<b>Soil fertility constraints and yield gaps of irrigation wheat in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100011&lng=es&nrm=iso&tlng=es South Africa currently faces a wheat (Triticum aestivum L.) crisis as production has declined significantly over the past few years. The objective of this study was to explore opportunities for improving yields in intensive irrigated wheat production systems of South Africa through analyses of yield gaps, soil fertility constraints and conservation agriculture practices. The study was conducted in the major irrigation wheat production areas across four geographical regions: KwaZulu-Natal, eastern Highveld, warmer northern and cooler central. Actual yield (Ya) based on long-term yield data ranged from 5.99±0.15 t/ha to 8.32±0.10 t/ha across different geographical regions. The yield potential (Yp) ranged from 7.57 t/ha to 11.45 t/ha. Yield gaps (Yp-Ya) were in the range of 1.58-3.13 t/ha. Yields could be increased by 26-38% through closing yield gaps. On 88.37% and 13.89% of the fields in the KwaZulu-Natal and warmer northern regions, respectively, there was strong evidence of the practise of conservation agriculture, but none in the other regions. On 42.31% of irrigated wheat fields, soil organic carbon was below 1% at a soil depth of 0-20 cm. Fields in which conservation tillage was practised had double the soil organic carbon of conventionally tilled fields (2.15±0.10% versus 1.02±0.05%), but greater acidity and phosphorus deficiency problems. Sustainable approaches for addressing phosphorus deficiency and acidity under conservation tillage practices need to be sought, especially in the KwaZulu-Natal region. SIGNIFICANCE: • Opportunities for improving wheat yields in South Africa need to be explored to address the wheat crisis. • Sustainable approaches for addressing phosphorus deficiency and acidity of soil under conservation tillage practices need to be sought, especially in the KwaZulu-Natal region. <![CDATA[<b>On the mental toughness of self-aware athletes: Evidence from competitive tennis players</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100012&lng=es&nrm=iso&tlng=es This study examined the relationship between mental toughness (MT) and self-awareness in a sample of 175 male and 158 female South African tennis athletes (mean age = 29.09 years, s.d. = 14.00). The participants completed the Sport Mental Toughness Questionnaire and the Self-Reflection and Insight Scale to assess MT (confidence, constancy, control) and self-awareness (self-reflection and self-insight) dimensions, respectively. Linear regression indicated that self-insight (β=0.49), but not self-reflection (β=0.02), predicted global MT. Multivariate regression analyses were significant for self-reflection (ηp2=0.11) and self-insight (ηp2=0.24). Self-reflection predicted confidence and constancy (ηp2=0.05 and 0.06, respectively), whereas self-insight predicted all three MT subcomponents (ηp2=0.12 to 0.14). The findings extend prior qualitative research evidence supporting the relevance of self-awareness to the MT of competitive tennis athletes, with self-reflection and insight forming prospective routes through which athletes' MT may be developed. SIGNIFICANCE: • Self-awareness attributes were predictive of higher levels of mental toughness among competitive tennis players. • Dimensions of self-awareness may offer routes for developing athletes' mental toughness. <![CDATA[<b>Osteopathology and insect traces in the <i>Australopithecus africanus</i> skeleton StW 431</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100013&lng=es&nrm=iso&tlng=es We present the first application of high-resolution micro computed tomography in an analysis of both the internal and external morphology of the lumbar region of StW 431 - a hominin skeleton recovered from Member 4 infill of the Sterkfontein Caves (South Africa) in 1987. The lumbar vertebrae of the individual present a number of proliferative and erosive bony processes, which were investigated in this study. Investigations suggest a complex history of taphonomic alteration to pre-existing spinal degenerative joint disease (SDJD) as well as post-mortem modification by an unknown insect. This study is in agreement with previous pathological diagnoses of SDJD which affected StW 431 and is the first time insect traces on this hominin are described. The results of this analysis attest to the complex series of post-mortem processes affecting the Sterkfontein site and its fossil assemblages. SIGNIFICANCE: • First application of high-resolution micro computed tomography of the lumbar region of StW 431, a partial skeleton of Australopithecus africanus, attests to pre-existing degenerative joint disease and identifies post-mortem modification by an unknown insect. • The co-occurrence of degenerative pathology and insect modification may not be unique to StW 431. A combination of traditional morphoscopic analysis and non-invasive high-resolution tomography is recommended. <![CDATA[<b>Attenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersrand</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100014&lng=es&nrm=iso&tlng=es Wetlands are well known to be efficient at sequestering pollutants from contaminated water. We investigated metal accumulation in the peats of the Klip River, a natural wetland that has received contaminated water from gold mining operations in Johannesburg for over 130 years. Previous work conducted in the downstream portion identified the wetland as an important system for sequestering metals. We focused on the upstream section of the wetland, more proximal to the source of acid mine drainage, to provide a better understanding of the pollutant sources and the role of the wetland in pollutant attenuation. Geochemical and mineralogical analyses of peat cores revealed considerable metal enrichments in the peat ash, particularly in Co, Ni, Zn, Pb, Cu and U. Metal concentrations are typically between 4 to 8 times higher than those previously reported for the downstream, more distal portion of the wetland. The distribution of metal accumulation within the peat profiles suggests that contamination arises from a combination of sources and processes. Elevated concentrations in the shallow peat are attributed to the input of contaminated surface water via tributaries that drain the Central Rand Goldfield, whereas enrichments in the deeper peat suggest significant sub-surface inflow of contaminated water through the underlying dolomitic rocks. Metal immobilisation occurs through a combination of mechanisms, which include the precipitation of gypsum, metal sulfides, Fe-Mn oxyhydroxides and phosphates. Our study highlights the environmental and economic importance of natural wetland systems which have the ability to accumulate large quantities of metals and thus remediate polluted waters. SIGNIFICANCE: • Considerable levels of metal accumulation are observed within the Klip River wetland peats. • The wetland is effective in remediating highly polluted water emanating from the Witwatersrand Basin. • The Klip River system is important for the region's future water supply. <![CDATA[<b>Stormwater harvesting: Improving water security in South Africa's urban areas</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532017000100015&lng=es&nrm=iso&tlng=es The drought experienced in South Africa in 2016 - one of the worst in decades - has left many urbanised parts of the country with limited access to water, and food production has been affected. 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. Within urban areas, municipalities must find ways to adapt to, and mitigate the threats from, water insecurity resulting from, inter alia, droughts, climate change and increasing water demand driven by population growth and rising standards of living. Stormwater harvesting (SWH) is one possible alternative water resource that could supplement traditional urban water supplies, as well as simultaneously offer a range of social and environmental benefits. We set out three position statements relating to how SWH can: improve water security and increase resilience to climate change in urban areas; prevent frequent flooding; and provide additional benefits to society. We also identify priority research areas for the future in order to target and support the appropriate uptake of SWH in South Africa, including testing the viability of SWH through the use of real-time control and managed aquifer recharge. SIGNIFICANCE: • Addresses water scarcity through building resilience to the impacts of climate change; improving the liveability of cities; and prioritising water-sensitive urban design.