Showing papers in "South African Journal of Science in 2012"

An air quality assessment in the industrialised western Bushveld Igneous Complex, South Africa

Abstract: South Africa has the largest industrialised economy in Africa, with significant mining and metallurgical activities. A large fraction of the South African mineral assets is concentrated in the Bushveld Igneous Complex (BIC), with the western limb being the most exploited. Because the majority of the world’s platinum is produced in the BIC, this area is also of international interest. There are some indications that the western BIC should be considered an air pollution hotspot; however, inadequate data exist to substantiate these claims scientifically. To partially address this knowledge gap, a comprehensive air quality monitoring station was operated for more than 2 years in this area. Meteorological parameters, trace gas concentrations and total mass concentration of particulate matter up to 10 µm in size (PM 10 ) were measured. Compared with South African and European ambient air quality standards, SO 2 , NO 2 and CO concentrations were generally acceptable. The major sources of SO 2 were identified as high-stack industry emissions, while household combustion from semi-formal and informal settlements was identified as the predominant source of NO 2 and CO. In contrast, O 3 exceeded the 8-h moving average more than 322 times per year. The main contributing factor was identified to be the influx of regional air masses, with high O 3 precursor concentrations. PM 10 exceeded the current South African 24-h standard 6.6 times per year, the future (2015) standard 42.3 times per year and the European standard more than 120 times per year. The main source of PM 10 was identified as household combustion from semi-formal and informal settlements. The findings clearly indicate that atmospheric O 3 and PM 10 levels in the western BIC need to be addressed to avoid negative environmental and human health impacts.

Overweight and obesity in children and adolescents: The South African problem

Abstract: Overweight and obesity in children and adolescents are on the increase worldwide.Overweight and obesity increase the risk for the development of non-communicable diseases during childhood and adolescence, and predispose the individual to the development of overweight, obesity,ardiovascular disease, and metabolic and other disorders in adulthood.In Africa the number of overweight or obese children has doubled since 1990. In South Africa,overweight and obesity in children and adolescents are on the increase, but the prevalencevaries with age, gender and population group. These differences are important when intervention programmes and policies are considered. South Africa faces a double burden of disease where undernutrition and overweight or obesity are found in the same populations, in the same households and even in the same children. Malnutrition is a major contributor to the double burden of disease in South African children and adolescents.

The lightning climatology of South Africa

Abstract: In 2005, the South African Weather Service installed a state-of-the-art cloud-to-ground lightning detection network across the country. The data recorded by this network in 2006 was utilised in the development of an initial lightning climatology of South Africa. Until 2010, this climatology was based on data from a single year. This paper updates this climatology with the lightning data for the 2006–2010 period, which is the first actual lightning climatology by the South African Weather Service based on data covering 5 years. A number of different maps were created from these lightning data. These were lightning ground flash density, median peak kiloampere, percentage positive and average flash multiplicity maps. These four maps were in turn used to develop lightning intensity risk, positive lightning risk and total lightning risk maps. Analysis of the maps showed that the highest concentrations of lightning are found over the central to northern interior of the country, with areas along the northern parts of the eastern escarpment experiencing the highest flash densities and falling within the extreme risk category. Both the positive and total lightning risks are severe for almost the entire country. Only towards the west of the country does the lightning risk decrease. This lightning climatology can now be used throughout South Africa for various disciplines. It will be especially useful for setting lightning safety standards and identifying priority areas for installing lightning conductors and conducting public awareness campaigns.

Re-evaluating the NO2 hotspot over the South African Highveld

Abstract: Globally, numerous pollution hotspots have been identified using satellite-based instruments. One of these hotspots is the prominent NO 2 hotspot over the South African Highveld. The tropospheric NO 2 column density of this area is comparable to that observed for central and northern Europe, eastern North America and south-east Asia. The most well-known pollution source in this area is a large array of coal-fired power stations. Upon closer inspection, long-term means of satellite observations also show a smaller area, approximately 100 km west of the Highveld hotspot, with a seemingly less substantial NO 2 column density. This area correlates with the geographical location of the Johannesburg–Pretoria conurbation or megacity, one of the 40 largest metropolitan areas in the world. Ground-based measurements indicate that NO 2 concentrations in the megacity have diurnal peaks in the early morning and late afternoon, which coincide with peak traffic hours and domestic combustion. During these times, NO 2 concentrations in the megacity are higher than those in the Highveld hotspot. These diurnal NO 2 peaks in the megacity have generally been overlooked by satellite observations because the satellites have fixed local overpass times that do not coincide with these peak periods. Consequently, the importance of NO 2 over the megacity has been underestimated. We examined the diurnal cycles of NO 2 ground-based measurements for the two areas – the megacity and the Highveld hotspot – and compared them with the satellite-based NO 2 observations. Results show that the Highveld hotspot is accompanied by a second hotspot over the megacity, which is of significance for the more than 10 million people living in this megacity.

The first animals: ca. 760-million-year-old sponge-like fossils from Namibia

Abstract: One of the most profound events in biospheric evolution was the emergence of animals, which is thought to have occurred some 600–650 Ma. Here we report on the discovery of phosphatised body fossils that we interpret as ancient sponge-like fossils and term them Otavia antiqua gen. et sp. nov. The fossils are found in Namibia in rocks that range in age between about 760 Ma and 550 Ma. This age places the advent of animals some 100 to 150 million years earlier than proposed, and prior to the extreme climatic changes and postulated stepwise increases in oxygen levels of Ediacaran time. These findings support the predictions based on genetic sequencing and inferences drawn from biomarkers that the first animals were sponges. Further, the deposition and burial of Otavia as sedimentary particles may have driven the large positive C-isotopic excursions and increases in oxygen levels that have been inferred for Neoproterozoic time.

The first animals : ca. 760-million-year-old sponge-like fossils from Namibia : research article

Abstract: One of the most profound events in biospheric evolution was the emergence of animals, which is thought to have occurred some 600-650 Ma. Here we report on the discovery of phosphatised body fossils that we interpret as ancient sponge-like fossils and term them Otavia antiqua gen. et sp. nov. The fossils are found in Namibia in rocks that range in age between about 760 Ma and 550 Ma. This age places the advent of animals some 100 to 150 million years earlier than proposed, and prior to the extreme climatic changes and postulated stepwise increases in oxygen levels of Ediacaran time. These findings support the predictions based on genetic sequencing and inferences drawn from biomarkers that the first animals were sponges. Further, the deposition and burial of Otavia as sedimentary particles may have driven the large positive C-isotopic excursions and increases in oxygen levels that have been inferred for Neoproterozoic time.

‘God is my forest’ – Xhosa cultural values provide untapped opportunities for conservation

Abstract: In South Africa conservation is still largely framed in terms of Western scientific values, with a focus on material benefits to local communities, whilst little is known about the intangible values local people attach to nature and biodiversity. We explored the cultural, spiritual and emotional relationships with nature expressed by Xhosa people, within the Maputaland-Pondoland-Albany Hotspot, as well as the activities that mediate this relationship. A descriptive research approach was applied to document the emotions, meanings and values associated with landscape elements. This approach included group and individual interviews and ‘walk-in-the-woods’ interviews and participatory mapping exercises. Respondents portrayed a strong, although not always easily articulated, appreciation for nature, especially ihlathi lesiXhosa (‘Xhosa forest’, vegetation types within the Thicket Biome). Activities such as collecting fuelwood and other resources, hunting and time spent at initiation schools were described as key opportunities for spending time in nature. The benefits of being in nature were ascribed not only to the physical experience of the forest environment and its biota, but also to the presence of ancestral spirits. Being in nature thus contributes significantly to the physical, mental and spiritual well-being of local people, and is also integral to their sense of cultural identity. This study has made it clear that maintenance of biodiversity and natural vegetation is as much in the interest of the local community’s well-being as it is in the interest of conservation planners. We recommend that cultural values be incorporated into local conservation plans.

Science in South Africa : the dawn of a renaissance? : research article

Abstract: This article reports the findings of a scientometric analysis of South Africa's research performance during the period 2000-2010. A multitude of government incentives were introduced during the period and their effects have appeared in the country's research outputs. In contrast to earlier investigations, it was found that South Africa's world share of publications is on the verge of reaching the highest contribution ever. South Africa improved its international ranking by two positions during 2000-2010 and was ranked 33rd in the world during 2010. It is argued that, provided the plan of the Minister of Science and Technology to increase the research and development expenditure in the country materialises, South Africa may be on the verge of a scientific renaissance.

First fungal genome sequence from Africa: A preliminary analysis

Abstract: Some of the most significant breakthroughs in the biological sciences this century will emerge from the development of next generation sequencing technologies. The ease of availability of DNA sequence made possible through these new technologies has given researchers opportunities to study organisms in a manner that was not possible with Sanger sequencing. Scientists will, therefore, need to embrace genomics, as well as develop and nurture the human capacity to sequence genomes and utilise the ’tsunami‘ of data that emerge from genome sequencing. In response to these challenges, we sequenced the genome of Fusarium circinatum, a fungal pathogen of pine that causes pitch canker, a disease of great concern to the South African forestry industry. The sequencing work was conducted in South Africa, making F. circinatum the first eukaryotic organism for which the complete genome has been sequenced locally. Here we report on the process that was followed to sequence, assemble and perform a preliminary characterisation of the genome. Furthermore, details of the computer annotation and manual curation of this genome are presented. The F. circinatum genome was found to be nearly 44 million bases in size, which is similar to that of four other Fusarium genomes that have been sequenced elsewhere. The genome contains just over 15 000 open reading frames, which is less than that of the related species, Fusarium oxysporum, but more than that for Fusarium verticillioides. Amongst the various putative gene clusters identified in F. circinatum, those encoding the secondary metabolites fumosin and fusarin appeared to harbour evidence of gene translocation. It is anticipated that similar comparisons of other loci will provide insights into the genetic basis for pathogenicity of the pitch canker pathogen. Perhaps more importantly, this project has engaged a relatively large group of scientists including students in a significant genome project that is certain to provide a platform for growth in this important area of research in the future.

Beyond South Africa's 'indigenous knowledge - science' wars

Abstract: In this paper, the paradoxes and difficulties attending the notion of indigenous knowledge in South Africa are reviewed and an alternative dialogue about intellectual heritage is proposed. Beginning with a survey of debates on ‘indigenous knowledge’ and sciences in India, Australia and Latin America, the discussion draws attention to differences in regional discussions on the subject of knowledge diversity. Turning to the South African context, the paper foregrounds contradictions in the debate on traditional medicines and the sciences in relation to HIV. The bifurcation of ‘indigenous knowledge’ and ‘science’ is argued against. Debates on both indigenous knowledge and science within the critical humanities in South Africa have been characterised by denunciation: an approach which does not facilitate the important discussions needed on intellectual heritage, or on the relationship between sciences and coloniality. In dialogue with current research on the anthropology of knowledge, strategies are proposed to broaden the possibilities for scholarship on knowledge, sciences, and different ways of understanding the world.

Beyond South Africa's 'indigenous knowledge - science' wars : review article

Abstract: In this paper, the paradoxes and difficulties attending the notion of indigenous knowledge in South Africa are reviewed and an alternative dialogue about intellectual heritage is proposed. Beginning with a survey of debates on 'indigenous knowledge' and sciences in India, Australia and Latin America, the discussion draws attention to differences in regional discussions on the subject of knowledge diversity. Turning to the South African context, the paper foregrounds contradictions in the debate on traditional medicines and the sciences in relation to HIV. The bifurcation of 'indigenous knowledge' and 'science' is argued against. Debates on both indigenous knowledge and science within the critical humanities in South Africa have been characterised by denunciation: an approach which does not facilitate the important discussions needed on intellectual heritage, or on the relationship between sciences and coloniality. In dialogue with current research on the anthropology of knowledge, strategies are proposed to broaden the possibilities for scholarship on knowledge, sciences, and different ways of understanding the world.

Characterising agrometeorological climate risks and uncertainties : crop production in Uganda : research article

Abstract: Uganda is vulnerable to climate change as most of its agriculture is rain-fed; agriculture is also the backbone of the economy, and the livelihoods of many people depend upon it. Variability in rainfall may be reflected in the productivity of agricultural systems and pronounced variability may result in adverse impacts on productivity. It is therefore imperative to generate agronomically relevant seasonal rainfall and temperature characteristics to guide decision-making. In this study, historical data sets of daily rainfall and temperature were analysed to generate seasonal characteristics based on monthly and annual timescales. The results show that variability in rainfall onset dates across Uganda is greater than the variability in withdrawal dates. Consequently, even when rains start late, withdrawal is timely, thus making the growing season shorter. During the March-May rainy season, the number of rainy days during this critical period of crop growth is decreasing, which possibly means that crops grown in this season are prone to climatic risks and therefore in need of appropriate adaptation measures. A time-series analysis of the maximum daily temperature clearly revealed an increase in temperature, with the lower limits of the ranges of daily maximums increasing faster than the upper limits. Finally, this study has generated information on seasonal rainfall characteristics that will be vital in exploiting the possibilities offered by climatic variability and also offers opportunities for adapting to seasonal distribution so as to improve and stabilise crop yields.

Characterising agrometeorological climate risks and uncertainties: Crop production in Uganda

Abstract: Uganda is vulnerable to climate change as most of its agriculture is rain-fed; agriculture is also the backbone of the economy, and the livelihoods of many people depend upon it. Variability in rainfall may be reflected in the productivity of agricultural systems and pronounced variability may result in adverse impacts on productivity. It is therefore imperative to generate agronomically relevant seasonal rainfall and temperature characteristics to guide decision-making. In this study, historical data sets of daily rainfall and temperature were analysed to generate seasonal characteristics based on monthly and annual timescales. The results show that variability in rainfall onset dates across Uganda is greater than the variability in withdrawal dates. Consequently, even when rains start late, withdrawal is timely, thus making the growing season shorter. During the March–May rainy season, the number of rainy days during this critical period of crop growth is decreasing, which possibly means that crops grown in this season are prone to climatic risks and therefore in need of appropriate adaptation measures. A time-series analysis of the maximum daily temperature clearly revealed an increase in temperature, with the lower limits of the ranges of daily maximums increasing faster than the upper limits. Finally, this study has generated information on seasonal rainfall characteristics that will be vital in exploiting the possibilities offered by climatic variability and also offers opportunities for adapting to seasonal distribution so as to improve and stabilise crop yields.

Science in South Africa: The dawn of a renaissance?

Abstract: This article reports the findings of a scientometric analysis of South Africa’s research performance during the period 2000–2010. A multitude of government incentives were introduced during the period and their effects have appeared in the country’s research outputs. In contrast to earlier investigations, it was found that South Africa’s world share of publications is on the verge of reaching the highest contribution ever. South Africa improved its international ranking by two positions during 2000–2010 and was ranked 33rd in the world during 2010. It is argued that, provided the plan of the Minister of Science and Technology to increase the research and development expenditure in the country materialises, South Africa may be on the verge of a scientific renaissance.

Comparison of the mineral composition of leaves and infusions of traditional and herbal teas : research article

Abstract: Most research on teas has focused on organic composition and less attention has been given to the mineral composition. The aim of this study was to examine and compare the mineral compositions (Na, Mg, K, Ca, P, S, Fe, Mn, Zn, Cu and Al) of eight commonly consumed teas. The teas included three traditional black or green teas (from Africa, China and Sri Lanka) and five herbal teas - two from South America (mate and coca) and three from South Africa (rooibos, honeybush and Athrixia phylicoides). Analyses were conducted on five samples of dry tea leaves of each of the teas and their infusions (steeping time: 6 min) using identical techniques in inductively coupled plasma optical emission spectrometry (ICP-OES). It was found that each tea has a unique mineral profile. Dry tea leaves and their respective infusions also exhibited different mineral profiles. The tea infusions that contained relatively higher concentrations of beneficial minerals were mate, coca and Athrixia. High levels of aluminium were found in the traditional black and green teas whilst rooibos was high in sodium. Although teas are not rich sources of nutrients, the consumption of mate could contribute significantly to dietary manganese requirements.

Heavy metal contamination of vegetables cultivated in home gardens in the Eastern Cape

Abstract: The accumulation of some essential (copper, manganese and zinc) and toxic metals (lead and cadmium) in cultivated vegetables – Brassica oleracea (cabbage), Daucus carota (carrot), Allium cepa (onion), Spinacia oleracea (spinach) and Solanum lycopersicum (tomato) – was examined. The vegetables were locally cultivated in home gardens in Alice, a small town in the Eastern Cape Province of South Africa. Samples of these vegetables were randomly collected from residential areas, dried, digested and analysed for the heavy metals using inductively coupled plasma optical emission spectrometry. The concentrations of heavy metals in the vegetables were in the range of 0.01 mg/kg – 1.12 mg/kg dry weight for cadmium, 0.92 mg/kg – 9.29 mg/kg for copper, 0.04 mg/kg – 373.38 mg/kg for manganese and 4.27 mg/kg – 89.88 mg/kg for zinc. Lead was undetectable in all the samples. Results of analysis of soils from the area revealed that cadmium in soil was in the range of 0.01 mg/kg – 0.08 mg/kg, copper levels were 4.95 mg/kg – 7.66 mg/kg, lead levels were 5.15 mg/kg – 14.01 mg/kg and zinc levels were 15.58 mg/kg – 53.01 mg/kg. The concentration of manganese was the highest of all the metals, ranging between 377.61 mg/kg and 499.68 mg/kg, at all three residential sites. Although the concentrations in soils and vegetables of the critical heavy metals, such as lead and cadmium, may not pose a threat (according to FAO/WHO standards), the concentration of manganese was very high in spinach and soils, whilst that of zinc exceeded safe levels in spinach, onions and tomatoes. However, neither the soils nor the vegetables were consistently found to pose a risk to human health.

Equal channel angular pressing technique for the formation of ultra-fine grained structures

Abstract: Equal channel angular pressing is one of the techniques in metal forming processes in which an ultra-large plastic strain is imposed on a bulk material in order to make ultra-fine grained and nanocrystalline metals and alloys. The technique is a viable forming procedure to extrude materials by use of specially designed channel dies without substantially changing the geometry by imposing severe plastic deformation. This technique has the potential for high strain rate superplasticity by effective grain refinement to the level of the submicron-scale or nanoscale. Wereview recent work on new trends in equal channel angular pressing techniques and the manufacturing of die-sets used for the processing of metals and alloys. We also experimented on a copper alloy using the equal channel angular pressing technique to examine the microstructural, mechanical and hardness properties of the ultra-fine grained and nanocrystalline materials produced. After deformation, all samples were subjected to a hardness test and the results showed improved mechanical behaviour of the ultra-fine grained copper alloy that was developed. This research provides an opportunity to examine the significance of the equal channel angular pressing process for metals and alloys. That is, these ultra-fine grained materials can be used in the manufacturing of semi-finished products used in the power, aerospace, medical and automotive industries.

Challenges in invasive alien plant control in South Africa : news and views

Abstract: The Department of Environmental Affairs' strategic plan1 for 2012â??2017 outlines programmes and projects that collectively aim to (1) 'contribute to sustainable development, livelihoods,green and inclusive economic growth through facilitating skills development, employment creation and infrastructure development' and (2) 'restore and maintain vegetation structure and function in order to contribute to ecosystem services'. The largest programme is the Working for Water programme, which strives to control invasive alien species (until recently only plants), and in so doing to protect essential ecosystem services. Several related programmes on forests, fire, wetlands and energy address overlapping issues that can either assist with, or enhance the benefits of, invasive alien plant control. These programmes collectively have a 3-year budget of R7.8 billion, arguably the most generous funding for an environmental problem that South Africa has ever seen. Although Working for Water operated for 16 years under the administration of the Department of Water Affairs, its recent transfer to the Department of Environmental Affairs, its consolidation with other initiatives and its substantially increased funding offer opportunities to the scientific community to inform improvements in ecosystem management. Through careful monitoring, assessment and analysis, important lessons can be learned and fed back into the programmes to continually improve management.

Remote sensing land-cover change in Port Elizabeth during South Africa's democratic transition

Abstract: Urban population increase has caused significant urban landscape transformation globally. Before 1994, South Africa’s highly regulated urban growth was shaped by the restrictive Prevention of Illegal Squatters Act of 1951. After the abolishment of the act in the 1980s, the period of transition to democracy in the 1990s was characterised by an unprecedented urban population influx that caused a myriad of socio-economic and environmental challenges. These challenges have consequently compounded the need to monitor urban growth for the planning and optimisation of urban spaces. The limitations of traditional mapping methods, such as surveying and photogrammetry, in urban mapping are well documented. In the recent past, satellite remote sensing has emerged as one of the most viable urban mapping tools. Using post-classification comparisons, we sought to monitor major land use and land cover (LULC) changes in the city of Port Elizabeth during South Africa’s democratic transition (1990–2000). Images for 1990, 1995 and 2000 were acquired, geo-rectified and atmospherically corrected. An iterative self-organising data analysis (ISODATA) was then used to generate existing LULCs. Classes generated using ISODATA were then amalgamated to the city’s major LULCs and resultant classes were validated using aerial photographs and field visits. Results showed that ‘Built-up’ and ‘Bare surface’ LULC classes had the highest increase and decrease, respectively. There was no change in the ‘Beach or dune’ LULC, whereas ‘Green vegetation’ and ‘Water’ classes had minimal changes. This study illustrates the efficacy of remote sensing in monitoring urban change and the potential of remote sensing to aid decision-making in rapidly changing urban landscapes.

Comparison of the mineral composition of leaves and infusions of traditional and herbal teas

Abstract: Most research on teas has focused on organic composition and less attention has been given to the mineral composition. The aim of this study was to examine and compare the mineral compositions (Na, Mg, K, Ca, P, S, Fe, Mn, Zn, Cu and Al) of eight commonly consumed teas. The teas included three traditional black or green teas (from Africa, China and Sri Lanka) and five herbal teas – two from South America (mate and coca) and three from South Africa (rooibos, honeybush and Athrixia phylicoides). Analyses were conducted on five samples of dry tea leaves of each of the teas and their infusions (steeping time: 6 min) using identical techniques in inductively coupled plasma optical emission spectrometry (ICP-OES). It was found that each tea has a unique mineral profile. Dry tea leaves and their respective infusions also exhibited different mineral profiles. The tea infusions that contained relatively higher concentrations of beneficial minerals were mate, coca and Athrixia. High levels of aluminium were found in the traditional black and green teas whilst rooibos was high in sodium. Although teas are not rich sources of nutrients, the consumption of mate could contribute significantly to dietary manganese requirements.

Educational outcomes: Pathways and performance in South African high schools

Abstract: tracked to Grade 12 examination data sets. We examined the relationship between TIMSS mathematics performance and reaching Grade 12, the selection of and performance in Grade 12 mathematics, and success rates in the matriculation examination. The progression of students from schools serving middle-class (Subsystem M) and poorer students (Subsystem P, the majority) was compared. Firstly, mathematics achievement scores in South Africa are low and different performance patterns were shown between the two subsystems. Secondly, students who started with similar Grade 8 mathematics scores had different educational outcomes 4 years later. In Subsystem M schools, Grade 8 mathematics scores were a good indicator of who would pass matric, whilst this relationship was not as strong in Subsystem P schools. Thirdly, there was a stronger association between TIMSS Grade 8 scores and subject choice of matric mathematics in Subsystem M schools than in Subsystem P schools. Fourthly, there was a strong correlation between Grade 8 mathematics performance and matric mathematics achievement. Mathematics performance in the earlier years predicted later mathematics performance. To raise exit level outcomes, mathematics scores need to be raised by Grade 8 or earlier. To improve educational and labour market outcomes, the policy priority should be to build foundational knowledge and skills in numeracy.

First fungal genome sequence from Africa : a preliminary analysis : research article

Abstract: Some of the most significant breakthroughs in the biological sciences this century will emerge from the development of next generation sequencing technologies. The ease of availability of DNA sequence made possible through these new technologies has given researchers opportunities to study organisms in a manner that was not possible with Sanger sequencing. Scientists will, therefore, need to embrace genomics, as well as develop and nurture the human capacity to sequence genomes and utilise the 'tsunami' of data that emerge from genome sequencing. In response to these challenges, we sequenced the genome of Fusarium circinatum, a fungal pathogen of pine that causes pitch canker, a disease of great concern to the South African forestry industry. The sequencing work was conducted in South Africa, making F. circinatum the first eukaryotic organism for which the complete genome has been sequenced locally. Here we report on the process that was followed to sequence, assemble and perform a preliminary characterisation of the genome. Furthermore, details of the computer annotation and manual curation of this genome are presented. The F. circinatum genome was found to be nearly 44 million bases in size, which is similar to that of four other Fusarium genomes that have been sequenced elsewhere. The genome contains just over 15 000 open reading frames, which is less than that of the related species, Fusarium oxysporum, but more than that for Fusarium verticillioides. Amongst the various putative gene clusters identified in F. circinatum, those encoding the secondary metabolites fumosin and fusarin appeared to harbour evidence of gene translocation. It is anticipated that similar comparisons of other loci will provide insights into the genetic basis for pathogenicity of the pitch canker pathogen. Perhaps more importantly, this project has engaged a relatively large group of scientists including students in a significant genome project that is certain to provide a platform for growth in this important area of research in the future.

Southern Ocean Seasonal Cycle Experiment 2012 : seasonal scale climate and carbon cycle links

Abstract: In early May 2012, South Africa will take delivery of a new polar research ship, the SA Agulhas II, representing a significant investment of R1.6 billion in polar infrastructure to further strengthen South Africa’s presence in the polar region, particularly in support of its stewardship of the Southern Ocean and Antarctic Treaty obligations. This investment follows closely on recent DST–CSIR infrastructure investments in the Centre for High Performance Computing, used to run global ocean–climate models, an ocean robotics observational capability and five other new research facilities. Together, these investments offer opportunities to enhance South Africa’s advanced numerical and technological capacity as well as its impact on Southern Hemisphere polar climate and ecosystem science by using its geographical advantage. We are planning the first scientific programme that will capitalise on these major infrastructure investments: the Southern Ocean Seasonal Cycle Experiment (SOSCEx). The Southern Ocean is arguably the main source of medium-term uncertainty in terms of the effectiveness of global CO 2 mitigation plans. The reason for this is that the Southern Ocean plays both an important role in the uptake of anthropogenic CO 2 (50% of all ocean uptake) as well as in the very large (90 Gt/Cy) natural CO 2 exchange between the oceans and the atmosphere. The Southern Ocean is the only region where deep-ocean CO 2 reservoirs (38 000 Gt C) exchange directly with the smaller atmospheric reservoir (700 Gt C). Moreover, although 85% of all ocean productivity is supported by nutrients derived from the Southern Ocean, little is known about the sensitivity of these carbon and nutrient fluxes to climate change driven adjustments or – most importantly – at what scales these links couple. One of the important gaps in the reliable prediction of the response of the Southern Ocean carbon cycle to climate change is its sensitivity to seasonal, subseasonal forcings (in time) and mesoscales (in space). The Southern Ocean Carbon and Climate Observatory (SOCCO), a CSIR-led consortium, is planning SOSCEx, which will be a new type of large-scale experiment. SOSCEx reflects a shift from the historical focus on shipbased descriptive Southern Ocean oceanography and living resource conservation, to systemscale dynamics studies spanning much greater time and space scales. Our limited grasp on these climate and climate-feedback sensitivities are linked to key knowledge gaps on the scales that link climate to carbon. Moreover, existing global models show only weak agreement in terms of the seasonal cycle of the upper-ocean in both physical and biogeochemical indicators such as primary productivity (Lenton A, Tilbrook B 2011, personal communication, Aug 01). The seasonal cycle is one of the strongest modes of variability in the primary productivity and the carbon cycle of the Southern Ocean. Additionally it reflects the coupling between climate forcing and important ecosystem responses, such as productivity. 1

Challenges in invasive alien plant control in South Africa

Abstract: CITATION: Van Wilgen, B. W. et al. 2012. Challenges in invasive alien plant control in South Africa. South African Journal of Science, 108(11/12), Art. #1445, doi:10.4102/sajs.v108i11/12.1445.

A correlation for predicting the abrasive water jet cutting depth for natural stones

Abstract: The abrasive water jet (AWJ) cutting method has been used widely for the cutting and processing of materials because of its cool, damage-free, and precise cutting technique. Nowadays, the use of AWJ cutting in the natural stone industry is increasing. However, the effectiveness of AWJ cutting of natural stones is dependent on the rock properties and machine operating parameters. In this study, injection-type AWJ cutting was applied to 42 different types of natural stones to investigate the effects of rock properties and operating parameters on the cutting depth. Shore hardness, Bohme surface abrasion resistance and the density of the rocks were the most significant rock properties affecting the cutting depth. The working pump pressure and traverse velocity were the most significant operating parameters affecting cutting, as has been shown previously. The relationships between the rock properties or operating parameters and the cutting depth were evaluated using multiple linear and nonlinear regression analyses, and estimation models were developed. Some of the models included only rock properties under fixed operating conditions, and others included both rock properties and operating parameters to predict cutting depth. The models allow for the preselection of particular operating parameters for the cutting of specific rocks types. The prediction of cutting depth is a valuable tool for the controlled surface machining of rock materials.

The sustainable use approach could save South Africa's rhinos : commentary

Abstract: South Africa is facing a surge in rhino poaching driven by the high and rising price of rhino horn, which benefits criminals but not landholders or conservation agencies. It is estimated that illegal traders earned $5000/kg of rhino horn in 2009, rising to $10 000/kg in 2010 and $20 000/kg by the end of 2011, or $60 000 - $80 000 for each animal poached. Rhino conservation in South Africa has historically been hugely successful. From fewer than 100 rhinos in 1910, there are now 19 000 white rhinos and 2000 black rhinos, of which 4500 occur on private land. The income from live rhino sales has provided significant income to South African National Parks and provided 74.9% of KwaZulu-Natal's parks budget between 2008 and 2011. But rhinos now face the strange paradox that they are so valuable that the private sector is questioning whether it still wants them. At issue are the economic consequences of traditional conservation policy, and the extraordinary ways that these policies twist economic signals.

Review of NGO performance research published in academic journals between 1996 and 2008

Abstract: Globally, literature on the performance of development non-governmental organisations (NGOs) has increased. However, little is known regarding the distinctive characteristics of academic articles on factors influencing NGO performance. In a recent systematic review of research, published in English-language academic journals between 1996 and 2008, factors influencing NGO performance were investigated. From the 31 journal articles that met the inclusion criteria, this study examined the salient characteristics of NGO performance research in terms of, (1) the number of publications, (2) publication outlets (journals and journal cluster), (3) author collaboration (sole or joint authors), (4) author affiliation, (5) study location, (6) study period, (7) study topics and (8) method and sources of information. Findings showed a steady increase in the number of articles, published in a wide array of journals with over half of the articles published in development studies journals. Of the 31 articles, 21 were sole authored. Data were mainly sought from NGO directors, programme staff and donors; comparatively fewer studies collected data from beneficiaries. Studies were mainly conducted in developing countries, whilst most authors were affiliated to institutions in developed countries. Of the 13 authors who conducted studies in Africa only 3 were affiliated to an institution in Africa. This study confirmed the continued need for increased research on factors influencing NGO performance; revealed the low seeking of beneficiaries’ perspectives in NGO performance research despite the rhetoric of participatory development; and revealed the low number of published researchers in Africa and minimal collaborative efforts between ‘Northern’ and ’Southern’ researchers in this field.

The South African National Vegetation Database: History, development, applications, problems and future

Abstract: Southern Africa has been recognised as one of the most interesting and important areas of the world from an ecological and evolutionary point of view. The establishment and development of the National Vegetation Database (NVD) of South Africa enabled South Africa to contribute to environmental planning and conservation management in this floristically unique region. In this paper, we aim to provide an update on the development of the NVD since it was last described, near its inception, more than a decade ago. The NVD was developed using the Turboveg software environment, and currently comprises 46 697 vegetation plots (releves) sharing 11 690 plant taxa and containing 968 943 species occurrence records. The NVD was primarily founded to serve vegetation classification and mapping goals but soon became recognised as an important tool in conservation assessment and target setting. The NVD has directly helped produce the National Vegetation Map, National Forest Type Classification, South African National Biodiversity Assessment and Forest Type Conservation Assessment. With further development of the NVD and more consistent handling of the legacy data (old data sets), the current limitations regarding certain types of application of the data should be significantly reduced. However, the use of the current NVD in multidisciplinary research has certainly not been fully explored. With the availability of new pools of well-trained vegetation surveyors, the NVD will continue to be purpose driven and serve the needs of biological survey in pursuit of sustainable use of the vegetation and flora resources of the southern African subcontinent.

New hominin fossils from Kanapoi, Kenya, and the mosaic evolution of canine teeth in early hominins

Abstract: Whilst reduced size, altered shape and diminished sexual dimorphism of the canine–premolar complex are diagnostic features of the hominin clade, little is known about the rate and timing of changes in canine size and shape in early hominins. The earliest Australopithecus , Australopithecus anamensis , had canine crowns similar in size to those of its descendant Australopithecus afarensis , but a single large root alveolus has suggested that this species may have had larger and more dimorphic canines than previously recognised. Here we present three new associated dentitions attributed to A. anamensis , recently recovered from the type site of Kanapoi, Kenya, that provide evidence of canine evolution in early Australopithecus . These fossils include the largest mandibular canine root in the hominin fossil record. We demonstrate that, although canine crown height did not differ between these species, A. anamensis had larger and more dimorphic roots, more like those of extant great apes and Ardipithecus ramidus , than those of A. afarensis . The canine and premolar occlusal shapes of A. anamensis also resemble those of Ar. ramidus , and are intermediary between extant great apes and A. afarensis . A. afarensis achieved Homo -like maxillary crown basal proportions without a reduction in crown height. Thus, canine crown size and dimorphism remained stable during the early evolution of Australopithecus , but mandibular root dimensions changed only later within the A. anamensis–afarensis lineage, coincident with morphological changes in the canine–premolar complex. These observations suggest that selection on canine tooth crown height, shape and root dimensions was not coupled in early hominin evolution, and was not part of an integrated adaptive package.