Scielo RSS <![CDATA[South African Journal of Science]]> http://www.scielo.org.za/rss.php?pid=0038-235320190001&lang=pt vol. 115 num. 1-2 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Does more and better research result in greater and effective impact?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100001&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Radio, like you've never read it before</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100002&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>A tale of unusual dedication: The lives of JLB and Margaret Smith</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100003&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Reflections on demonstrating development-oriented innovations in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100004&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Using ocean robots on high-resolution profiling to capture the fast-flowing Agulhas Current</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100005&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Morphometric comparison of semicircular canals of <i>Parapapio broomi</i> and <i>P. jonesi </i>from Sterkfontein, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100006&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>The nature of international collaboration in the Benguela upwelling region, 2000-2016</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100007&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Science in the service of society: Is marine and coastal science addressing South Africa's needs?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100008&lng=pt&nrm=iso&tlng=pt The modern world is confronted with many and diverse social and environmental challenges of high complexity. In South Africa, rapid and sustainable development is needed to address high levels of poverty and unemployment but this development has to take place in the context of an environment that is already severely impacted by human activities. Sound and relevant scientific input and advice, covering the full scope of each challenge, is essential for effective decisions and actions to address the needs. South Africa has the benefit of strong scientific capacity but the country's National Development Plan reported that national research priorities were not always consistent with South Africa's needs. We investigate the validity of that conclusion in the coastal and marine sciences by examining presentations made at the 2017 South African Marine Science Symposium on the theme of 'Unlocking the ocean's economic potential whilst maintaining social and ecological resilience'. Despite the theme, only 21% of the presentations were judged to be actionable and directly relevant to societal needs, as defined by the criteria used. Less than 7% were evaluated as being interdisciplinary within the natural sciences and approximately 10% were found to include both natural and human sciences. Poor representation by the human sciences was also noteworthy. This preliminary assessment highlights the need for an urgent review of the disciplinary representation and approaches in marine and coastal science in South Africa in the context of the priority practical needs of the country now and into the future. SIGNIFICANCE: •Despite the urgent need for integrated scientific input and advice to guide responsible and sustainable national development, a preliminary snapshot of marine and coastal science in South Africa demonstrated a low regard for direct relevance and inter- and multidisciplinarity. •If these general results are verified by a more comprehensive review, urgent realignment of funding and incentives for marine and coastal science, and probably environmental science in general, is likely to be required to ensure science provides a greater service to society, which is the source of much of the country's research funding <![CDATA[<b>Growth and yield parameters of three cowpea (<i>Vigna unguiculata</i> L. Walp) lines as affected by planting date and zinc application rate</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100009&lng=pt&nrm=iso&tlng=pt Cowpea is one of the most important food legumes in most African countries. Cowpea is a valuable source of dietary protein for both humans and their livestock. There is limited information available on cowpea production and suitable agronomic practices, such as planting date, to best suit different environmental conditions in South Africa. Therefore, the objective of this study was to evaluate the effect of two locations on cowpea production and the effect of planting date as affected by zinc application rate. Field experiments were conducted at two locations (Bien Donne' and Nietvoorbij) in the Western Cape Province of South Africa, using two planting dates (2 October and 2 November), three cowpea lines (Veg1, M217 and Qukawa) and three zinc (Zn) fertiliser application levels (0 kg/ha, 15 kg/ha and 30 kg/ha) during the 2015 growing season. The experimental design was a randomised complete block with five replicates. The results showed that Veg1 and Qukawa lines performed significantly better in both vegetative and reproductive parameters when compared to M217 at both locations. Application of zinc fertiliser significantly (p<0.05) affected seed iron content in Veg1 and M217 at Bien Donne' and seed iron content in M217 and zinc content in Veg1 at Nietvoorbij. SIGNIFICANCE: •Cowpea lines Veg1 and Qukawa were the best performing lines in all parameters measured, making these two lines suitable for dual purpose cultivation. •Planting cowpea in November, rather than October, increased the crop production efficiency. •Cowpea showed a better overall total yield in the sandy soil of Bien Donne' than in the sandy loam clay soil of Nietvoorbij <![CDATA[<b>Genotoxicity of aqueous extracts of <i>Tulbaghia violacea</i> as determined through an <i>Allium cepa</i> assay</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100010&lng=pt&nrm=iso&tlng=pt Tulbaghia violacea (wild garlic) is commonly used in traditional medicine for the treatment of various ailments including fungal infections, gastrointestinal ailments, asthma, fever, colds and pulmonary tuberculosis. We assessed the potential genotoxic effects of water extracts from the leaves, stems and roots of T. violacea using the Allium cepa assay. Extracts at concentrations of 100, 250, 500 and 1000 μg/mL were tested on root meristems of A. cepa. Ethidium bromide was used as a positive control whereas distilled water acted as a negative control. The results reveal that as the concentrations of the water extracts of T. violacea increased, the mitotic indices decreased. Similarly, the percentage of chromosomal aberrations was dependent on the concentration as well as on which part of the plant was used. The six most common chromosome aberrations included laggard chromosomes, chromosome bridges, c-mitosis, sticky chromosomes, formation of binuclei and formation of trinuclei. The presence of micronucleated cells at interphase also increased as the concentration of the water extracts increased. The results confirm that water extracts of T. violacea exert significant genotoxic effects at higher concentrations, with the stem extracts being more toxic than the leaf and root extracts at similar concentrations. SIGNIFICANCE: •Water extracts of T. violacea - a plant commonly used in traditional medicine - were found to have significant genotoxic effects at higher concentrations <![CDATA[<b>The Pleistocene fauna of the Cape south coast revealed through ichnology at two localities</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100011&lng=pt&nrm=iso&tlng=pt East of Still Bay on the Cape south coast of South Africa lies a rugged, remote stretch of sea cliffs that expose Late Pleistocene aeolianites. A zone of dense concentration of fossil tracks occurs within this area. Two large rocks, which we call Roberts Rock and Megafauna Rock, were identified ~400 metres apart. These rocks contained a variety of trackways, individual tracks, burrow traces and invertebrate trace fossils on multiple bedding planes. Both rocks were found ex situ, but their context could be determined. Roberts Rock has subsequently slid into the ocean, and Megafauna Rock lies at the base of a coastal cliff. Probable trackmakers include elephant, long-horned buffalo, giant Cape horse, rhinoceros, medium and small artiodactyls, golden mole, birds and invertebrates. Dating studies at an adjacent site, which is comparable to the stratigraphy described here, indicate that both rocks were most likely deposited in Marine Isotope Stage 5e (~128-116 ka). Analysis and description of these tracksites confirms the potential of ichnology to complement the skeletal fossil record and to enhance the understanding of Pleistocene life in southern Africa. The ephemeral nature of such tracksites makes repeated visits to this coastline desirable, both to monitor the fate of known sites and to search for newly exposed trace fossil surfaces. SIGNIFICANCE: •Roberts Rock and Megafauna Rock are two remarkable fossil tracksites on the Cape south coast, which contain tracks of four members of the Late Pleistocene megafauna. They provide a glimpse of Pleistocene dune life and suggest an area teeming with large mammals. •These tracks were made on dune surfaces near an interface between the grassland of the Palaeo-Agulhas Plain and the inland Fynbos-Strandveld-Renosterveld. Faunal assemblages from both vegetation zones might therefore be recorded. •The trace fossil record and body fossil record both have inherent biases, but have the potential to independently provide complementary information on palaeofaunal composition. •The two rocks have provided the first South African records of fossil elephant tracks (as first described by Dave Roberts and colleagues in 2008), the first rhinoceros track and the first extinct giant Cape horse track, and track evidence of the extinct long-horned buffalo. •Roberts Rock has slumped into the ocean, and it provides an example of the fate of many exposed tracksites. Conversely, new sites frequently become exposed. This scenario stresses the need for regular ichnological surveys along this track-rich coastline to monitor existing sites and to search for new sites <![CDATA[<b>Palaeotopography of a Palaeolithic landscape at Bestwood 1, South Africa, from ground-penetrating radar and magnetometry</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100012&lng=pt&nrm=iso&tlng=pt In order to investigate the buried landscape at the Fauresmith locality of Bestwood 1, outside the town of Kathu in the Northern Cape Province, we performed ground-penetrating radar and magnetometry surveys across the sand-filled central portion of the valley. The radar images a strong continuous reflector which we can assign to the boundary between the Kalahari sands and underlying Banded Ironstone Formation gravels. Moreover, the thickness of the sand delineates a buried depression in the centre of the valley with flat plateaus at the sides. Subtracting the sand thickness from the current topography produces a map of a small stream channel in the northern part of the valley. Analysis of the magnetic gradient data allows us to extend this buried channel further to the south. Our geophysical survey provides a valuable contribution towards understanding the context of hominin occupation along the banks of a small stream in the Kathu Complex. SIGNIFICANCE: •We provide an example of combining two geophysical methods to map overburden thickness, useful for archaeological landscape interpretation <![CDATA[<b>Perfectionism and motivation in sport: The mediating role of mental toughness</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100013&lng=pt&nrm=iso&tlng=pt An extensive body of research has been done on the links between perfectionism and motivation, yet the underlying mechanisms linking these psychological characteristics have been underexplored. In this study, we used an integrative modelling approach to examine associations between dimensions of perfectionism (i.e. personal standards [PSP] and concerns over mistakes [CMP]), mental toughness (MT) and motivational orientations (i.e. self-determined motivation [SDM] and non-self-determined motivation [NSDM]). Based on a sample of 318 male (n=218) and female (n=100) tennis players (Mage=17.61, SDage=2.41), fit indices derived from structural equation modelling supported a partially mediated model. Residual PSP associated positively with MT (β=0.74) and SDM (β=0.40), and negatively with NSDM (β=-0.22). Conversely, residual CMP associated negatively with MT (β=-0.14) and SDM (β=-0.19), and positively with NSDM (β=0.73). Mental toughness was positively associated with SDM (β=0.28), but was unrelated to NSDM (β=0.07). The relationship between residual PSP and SDM was partially mediated by MT (standardised indirect effect: 95% CI=0.19, 0.46). The findings of this study support research linking dimensions of perfectionism with motivational orientations and offer preliminary evidence on the mediating role of MT in the association between these psychological constructs. With emerging research supporting the capacity to develop MT through targeted interventions, the findings are discussed alongside salient implications. SIGNIFICANCE: •Mental toughness partially mediated the association between pure personal standards perfectionism and self-determined motivation. •Particularly among athletes with higher personal standards of perfectionism, more autonomous forms of motivation may be sustained via efforts that seek to develop athletes' mental toughness <![CDATA[<b>Observations from SANSA's geomagnetic network during the Saint Patrick's Day storm of 17-18 March 2015</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100014&lng=pt&nrm=iso&tlng=pt Geomagnetic storms are space weather events that result in a temporary disturbance of the earth's magnetosphere caused by a solar wind that interacts with the earth's magnetic field. We examined more closely how some southern African magnetic observatories responded to the Saint Patrick's Day storm using local K-indices. We show how this network of observatories may be utilised to model induced electric field, which is useful for the monitoring of geomagnetically induced anomalous currents capable of damaging power distribution infrastructure. We show an example of the correlation between a modelled induced electric field and measured geomagnetically induced currents in southern Africa. The data show that there are differences between global and local indices, which vary with the phases of the storm. We show the latitude dependence of geomagnetic activity and demonstrate that the direction of the variation is different for the X and Y components. SIGNIFICANCE: •The importance of ground-based data in space weather studies is demonstrated. •We show how SANSA's geomagnetic network may be utilised to model induced electric field, which is useful for the monitoring of geomagnetically induced anomalous currents capable of damaging power distribution infrastructure <![CDATA[<b>The influence of science reading comprehension on South African township learners' learning of science</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100015&lng=pt&nrm=iso&tlng=pt The majority of South African township learners have poor reading comprehension skills, which is known to impact negatively on their understanding of content subjects such as science, although the extent of the impact is not fully understood. We explored this impact, as well as the extent to which reading comprehension accounted for the differential effectiveness observed for out-of-class, text-dependent science intervention programmes. Eye movement and mouse-click data were collected from 65 Grade-8 and Grade-9 township learners as they read texts and answered electronic quizzes about electric circuits and lightning on a computer fitted with eye-tracking hardware and software. These data were used to describe the learners' reading and question-answering patterns and derive a composite English for science and technology (EST) reading comprehension index for each learner. Correlations were sought between this index and the learners' Natural Sciences marks and the benefit gained from two previous out-of-school science intervention programmes. Most learners were able to engage meaningfully with a less text-rich, moderately familiar quiz, but there was a prevalence of reading avoidance, guessing and reliance on superficial text features to answer questions for a more text-rich, unfamiliar quiz. Moderate to strong correlations were found between the EST index and both Natural Sciences and intervention marks. The findings suggest that while a significant number of higher achieving township learners possess sufficient levels of EST reading comprehension skills to benefit from text-based interventions, the majority require help in developing EST reading comprehension skills to enhance the likelihood of the intervention's success. SIGNIFICANCE: •From this study, we infer that a small group of South African township learners, identifiable by their relatively high Natural Sciences marks, are able to read English science texts with sufficient comprehension to be able to benefit from text-dependent interventions, including engagement with self-study interactive software. The majority, however, read such texts at the frustration level, making it unlikely for interventions to be effective if they rely on the learner being able to engage in independent reading <![CDATA[<b>Comparing mathematics knowledge of first-year students from three different school curricula</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-23532019000100016&lng=pt&nrm=iso&tlng=pt Mathematics forms an integral part in the training of scientists and engineers. In recent history the South African school system has experienced several changes in school curricula. In 1994 the traditional knowledge-based curricula were replaced by an outcomes-based curriculum. Owing to implementation problems which resulted in resistance from teachers and the general public, revisions followed of which the National Curriculum Statement (NCS) and Curriculum Assessment Policy Statements had the most direct effect in terms of preparation for tertiary mathematics. We report here on an investigation of the basic mathematical knowledge of three student cohorts representing three curricula, namely the last cohort that received the traditional knowledge-based curriculum, and the first cohorts that received the two outcomes-based curricula. The results indicate that changes in the mathematical content of the curricula did not impact negatively on the basic mathematical knowledge of students enrolled for tertiary mainstream mathematics. The only exception is Euclidean geometry, for which certain topics were transferred to an optional paper in the NCS curriculum SIGNIFICANCE: •The introduction of outcomes-based curricula in South Africa initiated a discourse on the preparedness of first-year students for programmes with mainstream mathematics. •The availability of a homogeneous set of samples and a uniform test provided a unique opportunity to compare the basic mathematical knowledge of first-year natural science and engineering students entering university from three different exit-level school curricula