The geochemistry of potassic lavas from Vulsini, central Italy and implications for mantle enrichment processes beneath the Roman region
- Authors: Rogers, N W , Hawkesworth, C J , Parker, R J , Marsh, Julian S
- Date: 1985
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/136034 , vital:37330 , https://doi.org/10.1007/BF00378265
- Description: Major and trace element and 143Nd/144Nd (0.51209–0.51216) and 87Sr/86Sr (0.70879–0.71105) isotope analyses are presented on a representative group of lavas from the Vulsini district of the Roman magmatic province. Three distinct series are identified; the high-K and low-K series are similar to those described from other Italian volcanoes, while the third is represented by a group of relatively undifferentiated leucite basanites which are thought to be near-primary mantle melts.
- Full Text: false
- Date Issued: 1985
The distribution of platinum group elements in the Insizwa lobe, Mount Ayliff Complex, South Africa: implications for Ni-Cu-PGE sulfide exploration in the Karoo igneous province
- Authors: Maier, W D , Marsh, Julian S , Barnes, Sarah-Jane , Dodd, D C
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150353 , vital:38969 , https://0-doi.org.wam.seals.ac.za/10.2113/gsecongeo.97.6.1293
- Description: The Mount Ayliff Complex of the Eastern Cape province of South Africa is a layered intrusion of some 800 km2 surface area and up to 1,200 m thickness. On the basis of compositional similarities and spatial association, it is generally interpreted to form part of the Karoo igneous province. Similarities between the Mount Ayliff Complex and the staging chambers and feeder conduits to flood basalts that host magmatic sulfide ores elsewhere in the world suggest that the Mount Ayliff Complex may have an enhanced potential for Noril’sk-Talnakh–type massive Ni-Cu sulfide ores, an idea that is supported by the well-known sulfide occurrence at Waterfall Gorge.
- Full Text: false
- Date Issued: 2002
Sex work from a feminist perspective: a visit to the Jordan case
- Authors: Krüger, Rósaan
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68877 , vital:29335 , https://doi.org/10.1080/19962126.2004.11864812
- Description: Publisher version , Introduction: Contributors to the prostitution/sex work debate, whether they condone, support or oppose criminalisation, legalisation or decriminalisation of prostitution, often rely on ‘facts’ to support their arguments. A common fact is that the majority of prostitutes/sex workers in the world and in South Africa are women. Thus, when I refer to prostitutes/sex workers, I refer to women working as prostitutes in the commercial sex industry. Furthermore, the fact that the majority of sex workers are women justifies considering prostitution from a feminist perspective – women’s voices on the subject should be heard. In this note I shall use the terms ‘prostitution’ and ‘sex work’ to refer to the exchange of sexual services for money. The former, more conventional term has a negative connotation, while the term ‘sex work’ denotes a movement away from casting a moral judgment towards recognition that sex work is just another job. References will be made to the associated activities of brothel-keeping and pimping, but the focus of this note is mainly on the provision of sexual services by the prostitute/ sex worker herself. Jordan v S is a Constitutional Court judgment in which the constitutional validity of the criminalisation of prostitution and its related activities were challenged. In order to analyse this judgment from a feminist perspective, I shall first briefly set out the current legal position on prostitution. Thereafter, I shall give an overview of Western feminist perspectives on prostitution and then link this perspective with African feminism. The last part of the note will be an analysis of the Jordan judgment in light of the feminist perspectives identified before.
- Full Text: false
- Date Issued: 2004
Introducing a learning management system in a large first year class: impact on lecturers and students
- Authors: Snowball, Jeanette D , Mostert, Markus
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68631 , vital:29297 , https://hdl.handle.net/10520/EJC37639
- Description: Publisher version , The challenges of teaching large classes are well documented in the literature on teaching in higher education. Information and communication technologies (ICTs) have the potential to address some of these challenges, but, used inappropriately, technology can perpetuate entrenched practices and simply support performance models of teaching that encourage transmission approaches to learning. This article reports on the impact of implementing a learning management system (LMS) in a first year introductory macroeconomics course with 600 students in a blended learning context. Experiences of the course coordinator, lecturers and an educational technologist are discussed and data was also collected on student perceptions via a course evaluation questionnaire. Results show that the LMS was successful in a number of areas, particularly in improving the lecturers' accessibility to students and in encouraging interaction and participations in online discussion forums.
- Full Text: false
- Date Issued: 2010
Radical thinking in South Africa’s age of retreat
- Authors: Helliker, Kirk D , Vale, Peter C J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71214 , vital:29818 , https://doi.org/10.1177/0021909612442654
- Description: This article traces the rise and fall of radical praxis in South Africa and offers a critique of the prevailing practices of former Marxists under post-apartheid conditions. Western Marxism emerged in the 1970s in South Africa and Marxist activists became deeply involved in the liberation movements. With the unravelling of apartheid, the main liberation forces made a social pact with capitalist forces and former Marxists embraced a statist project. In the context of the rise of ‘new’ social movements, radical thinking of a more Libertarian kind is emerging in contemporary South Africa.
- Full Text: false
- Date Issued: 2012
Dancing with the devil: formative peer assessment and academic performance
- Authors: Mostert, Markus , Snowball, Jeanette D
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69301 , vital:29483 , https://doi.org/10.1080/07294360.2012.705262
- Description: Peer assessment can be important in developing active and independent learners, as well as providing more and faster feedback in large classes, compared to marking done by tutors. In addition, the evaluative, critical stance required by students in order to assess their peers' work encourages the development of higher-order cognitive skills. Changing roles from being assessed to being an assessor can also improve students' ability to judge and improve on their own work. However, peer assessment does have potential problems and there is some debate as to the appropriate academic level at which to implement it, the kinds of feedback that are given and the ways in which students respond. In addition, there is little evidence that peer assessment has an impact on academic performance. This research reports the results of an online peer assessment exercise for a macroeconomics essay conducted in a large Economics 1 class at Rhodes University. Of the 800 students, about half participated in the peer assessment exercise. Data were collected from students via a formal course evaluation. In addition, a sample of 50 essays was evaluated in terms of the relationship between peer marks and final (tutor) marks received and the impact that peer assessment had on the quality of the final essay submitted. An Ordinary Least Squares regression was used to investigate the impact of peer assessment participation on marks. Results showed that peer marks tended to ‘bunch’ in the 60–68% range, indicating the reluctance of peers to give very high or low marks. In general, peers gave more useful feedback on technical aspects, such as presentation and referencing (which were also the categories in which students most often made improvements), than on content. Regression analysis showed that peer assessment participation was not a significant determinant of final essay mark, but that economics ability and English language proficiency were.
- Full Text: false
- Date Issued: 2013
Where angels fear to tread: online peer-assessment in a large first-year class
- Authors: Mostert, Markus , Snowball, Jeanette D
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68845 , vital:29330 , https://doi.org/10.1080/02602938.2012.683770
- Description: Publisher version , In the context of widening participation, large classes and increased diversity, assessment of student learning is becoming increasingly problematic in that providing formative feedback aimed at developing student writing proves to be particularly laborious. Although the potential value of peer assessment has been well documented in the literature, the associated administrative burden, also in relation to managing anonymity and intellectual ownership, makes this option less attractive, particularly in large classes. A potential solution involves the use of information and communication technologies to automate the logistics associated with peer assessment in a time-efficient way. However, uptake of such systems in the higher education community is limited, and research in this area is only beginning. This case study reports on the use of the Moodle Workshop module for formative peer assessment of students’ individual work in a first-year introductory macro-economics class of over 800 students. Data were collected through an end-of-course evaluation survey of students. The study found that using the feature-rich Workshop module not only addressed many of the practical challenges associated with paper-based peer assessments, but also provided a range of additional options for enhancing validity and reliability of peer assessments that would not be possible with paper-based systems.
- Full Text: false
- Date Issued: 2013
‘Growing’ social protection in developing countries: lessons from Brazil and South Africa
- Authors: Barrientos, Armando , Moller, Valerie , Saboia, Joao , Lloyd-Sherlock, Peter , Mase, Julia
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67195 , vital:29058 , https://doi.org/10.1080/0376835X.2013.756098
- Description: publisher version , The rapid expansion of social protection in the South provides a rich diversity of experiences and lessons on how best to reduce poverty and ultimately eradicate it. Knowledge on how best to ‘grow’ social assistance, understood as long-term institutions responsible for reducing and preventing poverty, is at a premium. This article examines the expansion of social assistance in Brazil and South Africa, two of the middle income countries widely perceived to have advanced furthest in ‘growing’ social protection. It examines three aspects: the primacy of politics in explaining the expansion of social protection and assistance, the tensions between path-dependence and innovation in terms of institutions and practices, and the poverty and inequality outcomes of social assistance expansion. The article concludes by drawing the main lessons for other developing countries.
- Full Text: false
- Date Issued: 2013
Stable isotope ratios indicate differential omnivory among syntopic rocky shore suspension-feeders
- Authors: Richoux, Nicole B , Vermeulen, Ilke , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68261 , vital:29224 , https://doi.org/10.1007/s00227-013-2358-6
- Description: Publisher version , We utilised stable isotope ratios to assess differences in diet among three indigenous and syntopic rocky shore suspension-feeders (mussels Perna perna, barnacles Tetraclita serrata, and polychaetes Gunnarea gaimardi). We also determined the spatial and temporal variability in the suspension-feeder diets by collecting specimens on two occasions from two regions adjacent to hydrologically distinct river mouths (i.e. one with larger annual freshwater throughput than the other). The results showed that the isotopic niches (used as proxies for trophic niches) of the three species did not overlap and that the barnacles occupied a trophic position (3.4) well above those of the mussels (2) and polychaetes (2.6). We ascribed the interspecific differences primarily to the disparate feeding mechanisms used by the species. Large-scale regional (~50 km) differences in suspension-feeder diets were apparent, but not small-scale (up to a few km north and south of each estuary mouth). The regional differences in diet resulted from the increased availability of estuarine-origin suspended particulate matter (SPM) and zooplankton in the region adjacent to the river with relatively larger freshwater output, although overall incorporation of zooplankton versus mixed SPM into consumer diets was relatively consistent between regions and through time. Temporal shifts in suspension-feeder diets were apparent from stable carbon isotope ratios in the consumers. Our results showcase the measurable effects of regional-scale processes that can alter the food sources for dominant primary consumers in the rocky intertidal, thus potentially affecting entire food webs through bottom-up processes. The clear evidence for trophic niche partitioning offers valuable insights into how potentially strong competitors can coexist.
- Full Text: false
- Date Issued: 2014
Reinventing the oral word and returning it to the community via technauriture
- Authors: Kaschula, Russell H , Dlutu, Bongiwe
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/67052 , vital:29024 , https://books.google.co.za/books?id=6IpwCgAAQBAJ
- Description: publisher version , From Introduction: The aim of this article is to situate the importance of orality in rural communities within the paradigm of Technauriture, which is defined below. The chapter will also explore/describe the process of orality supported through community meetings, oral histories, and story-telling, and how it interacts with the recording process facilitated through modern technology, as well as the return of the oral material via technology. These objectives will be pursued as part of empirical data collected at Tshani, an area falling within the in Mankosi tribal authority in the Eastern Cape Province of South Africa. Mankosi’s twelve villages are inhabited by amaXhosa people and is situated in the Ngqeleni district in the former Transkei region. Mankosi is about 76 kilometres away from Mthatha, the major city in that area. These villages are under the Nyandeni Local Municipality and are regarded as very disadvantaged. There is poor sanitation, gravel roads, and few local people have access to electricity. Most of the villagers depend on government support grants. These include Child Support Grants, Old Age Grants, Disability Grants, and Foster-Care Grants. Furthermore, most of the community is involved in small-scale agriculture for survival. People often move, temporarily, from their village to towns in order to gain employment, including domestic work and working on the mines in the mineral rich Gauteng Province. They send cash remittances home to their families. The primary technological devices that people in the village are familiar with would be radio and the cell phone. Even television sets are relatively uncommon.
- Full Text: false
- Date Issued: 2015
Towards shaping the field: theorising the knowledge in a formal course for academic developers
- Authors: Vorster, Jo-Anne , Quinn, Lynn
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66578 , vital:28966 , https://doi.org/10.1080/07294360.2015.1070126
- Description: publisher version , In recent years there have been calls both for building the knowledge base of academic development (AD) and for systematic induction of newcomers to the field if AD is to advance as a professional and an academic field. Despite the importance and complexity of AD, induction of novice academic developers remains mostly informal and predominantly focuses on the practices of the field. We argue that more-experienced academic developers have an obligation to provide formal and systematic routes into the field and its knowledge base than is currently the case. One way of doing this is through offering a formal course for growing the next generation of academic developers. Such a course could equip newcomers with a more solid and shared knowledge base, thus contributing to shaping the epistemic spine of AD. In this paper, using Maton's Legitimation Code Theory, we offer an analysis of an existing course aimed at equipping novices with the theoretical and practical knowledge to enable them to solve some of the problems in higher education. From this analysis have emerged general principles that could inform the selection, sequencing and pacing of knowledge in a formal course for academic developers.
- Full Text: false
- Date Issued: 2015
A feminist perspective on autonomism and commoning, with reference to Zimbabwe
- Authors: Alexander, Tarryn , Helliker, Kirk D
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71374 , vital:29838 , https://doi.org/10.1080/02589001.2016.1235353
- Description: This article engages with the autonomist Marxism of John Holloway from a feminist standpoint. The positions developed by this feminist critique are used to shed new light on the land occupations in contemporary Zimbabwe. Though sympathetic to his work, we argue that Holloway does not sufficiently address gender identity with specific reference to social reproduction and women. The notions of the commons and the process of commoning are consistent with Holloway’s autonomist framework and its complementarities to Silvia Federici’s Marxist feminist lens on the commons is highlighted. Against a tendency within autonomist and commoning theories, we argue for a pronounced identitarian politics as grounded in localised struggles undertaken by women as women. We privilege the significance of women asserting and revaluing their identities as part of a possible project of transformation. For us, struggling against and beyond what exists is invariably rooted in struggles within what exists (including identities).
- Full Text: false
- Date Issued: 2016
A passive auxiliary circuit with interphase transformer applied in 12-pulse converters to provide clean power utility interface
- Authors: Shih, Der-Chun , Young, Chung-Ming , Whiteley, Chris G
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67095 , vital:29031 , https://doi.org/10.1080/02533839.2016.1230029
- Description: publisher version , This paper proposes a passive auxiliary circuit which can be added to an interphase transformer (PAC + IPT) configuration to reduce the total harmonic distortion (THD) existing in 12-pulse diode rectifier converter systems at AC mains. The proposed PAC + IPT compensation method is a simple structure, with low power consumption and requires no extra DC power supply. We present the theoretical analysis of the proposed topology that lessens the total harmonic distortion (THD) and evaluate the dynamic simulation results on a 12-pulse converter system and a 3-kW laboratory prototype. Both the simulation and the experimental results show that the proposed PAC + IPT compensation method can improve the power quality and provide a clean power utility interface of AC line input currents for a conventional 12-pulse diode rectifier converter.
- Full Text: false
- Date Issued: 2016
Effects of substrate on essential fatty acids produced by phytobenthos in an austral temperate river system
- Authors: Dalu, Tatenda , Galloway, Aaron W E , Richoux, Nicole B , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68002 , vital:29179 , https://doi.org/10.1086/688698
- Description: Publisher version , Aquatic and riparian habitats increasingly are affected by anthropogenic stressors, but the effects of these stressors on the nutritional quality of primary producers are often unknown. We compared essential fatty acids (EFAs) in the phytobenthos (benthic algae) growing on different substrate types (bricks, clay tiles, rocks, macrophytes, and sediments) at 2 river sites subject to differing anthropogenic stressors (using nutrient concentration as a proxy) in a temperate southern hemisphere location. We hypothesized that the fatty acid (FA) content of phytobenthos changes in response to shifts in local nutrient availability but not substrate type. EFA content (18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3, and 22∶6ω3) in the phytobenthos differed overall among substrates, sites, and seasons and was generally greater in summer than in autumn and winter. EFA content was significantly greater on artificial than natural substrates and was greater at the nutrient-enriched downstream site than at the upstream site. The response of EFA content at the downstream site suggests that land use affected the synthesis of EFAs by phytobenthos and, hence, food quality for aquatic consumers. These findings indicate a potential link between physical factors, such as substrate availability and land management, and the quality of basal food resources available to primary consumers in aquatic food webs.
- Full Text: false
- Date Issued: 2016
Film production incentives, employment transformation and domestic expenditure in South Africa: visualizing subsidy effectiveness
- Authors: Collins, Alan , Ishizaka, Alessio , Snowball, Jeanette D
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67456 , vital:29094 , https://doi.org/10.1080/10286632.2016.1255206
- Description: Publisher version , In 2004 the South African Department of Trade and Industry (DTI) introduced a Film and Television Production Rebate Programme. In order to qualify for the rebate, certain criteria have to be met including success in job creation and skills development within the industry, alongside a particular focus on the percentage of ‘historically disadvantaged individuals’ employed. This study sets out the issues associated with evaluating success in meeting these various criteria and is, to the best of our knowledge, the first study to apply multi-criteria visualization techniques to inform the evaluation of public subsidy effectiveness. The ‘PROMETHEE’ method is applied and apart from presenting project performance in a visually intuitive manner, the approach helps to clarify patterns of relative success, show where policy objectives are competing, and to identify project exemplars for more efficiently guiding future public support in the sector.
- Full Text: false
- Date Issued: 2016
Trophic interactions in an austral temperate ephemeral pond inferred using stable isotope analysis
- Authors: Dalu, Tatenda , Weyl, Olaf L F , Froneman, P William , Wasserman, Ryan J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68022 , vital:29185 , https://doi.org/10.1007/s10750-015-2533-5
- Description: Publisher version , Ephemeral ponds are vulnerable aquatic habitats which are difficult to protect given their dynamic nature and sensitivity to degradation during dry periods. Little information is available on these habitats in austral regions, with almost no information on food-web structure and complexity. The study aimed to assess trophic interactions among dominant organisms in an ephemeral pond food web, and investigate the importance of autochthonous and allochthonous carbon, using 13C and 15N isotopes. Results of the investigation suggest that the food web comprised four trophic levels, with the top predators being Notonectids (Notonecta sp.) and diving beetles (Cybister tripunctatus (Olivier)). Intermediary trophic levels comprised zooplankton (daphniids and copepodids), macroinvertebrates (e.g. micronectids and molluscs) and tadpoles. Generalist feeders dominated the higher trophic levels (>3) with specialists comprising the lower trophic levels (≤3). The consumers preferred autochthonous fine particulate organic matter, epiphyton and submerged macrophyte organic matter sources over allochthonous sources. Autochthonous organic matter was transferred to the food web via zooplankton and select macroinvertebrates including Micronecta sp. and Physa sp. The food-web structure within the pond appeared to reflect the secondary stage of trophic structural complexity in the evolution of ephemeral ponds over the course of their hydro-period.
- Full Text: false
- Date Issued: 2016
Fuelwood preferences, use and availability in the #Khomani San resettlement farms, southern Kalahari, South Africa
- Authors: Nott, Michelle , Thondhlana, Gladman
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67667 , vital:29127 , https://doi.org/10.1080/14728028.2017.1294507
- Description: Publisher version , Local level assessments of fuelwood preferences, demand and supply are important for ensuring a balance between ecological functions and livelihood needs. This study reports on an examination of fuelwood preferences, use and abundance in the #Khomani San resettlement farms in southern Kalahari, South Africa. The results show that Acacia erioloba was the most preferred fuelwood species, while Acacia mellifera was abundant but avoided. Across the study area, there were approximately 64 trees ha−1 but riverine sites had significantly more trees (approximately 80 trees ha−1) than non-riverine sites (48 trees ha−1). Live trees showed evidence of damage (cutting or breaking) and this was more pronounced in the riverine sites (close to human settlement) than in the non-riverine sites. However, overall current woody stocks and productivity rates of harvestable fuelwood are well above current fuelwood demand, suggesting fuelwood use may be within sustainable limits, though there is evidence of localised fuelwood depletion. The implications of these results for fuelwood management interventions, including the importance of context, are discussed.
- Full Text: false
- Date Issued: 2017