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A possible relation between dietary zinc and cAMP in the regulation of tumour cell proliferation in the rat

- Skeef, Noel S, Duncan, John R

Authors: Skeef, Noel S , Duncan, John R
Date: 1988
Language: English
Type: Article
Identifier: vital:6473 , http://hdl.handle.net/10962/d1006154 , http://dx.doi.org/10.1079/BJN19880052
Description: The possibility of an effect of zinc on the rate of tumour cell division, mediated through a regulation of cellular cAMP concentration, was investigated in the present study in rats. Dietary Zn deficiency (< 1·5 mg Zn/kg) but not Zn excess (500 mg Zn/kg) resulted in an increased cAMP concentration in transplanted hepatoma cells. Neither treatment had any effect on the cAMP concentration in regenerating liver or normal resting liver. Both the deficient and excess Zn diets resulted in a small reduction in tumour growth (not statistically significant). The results seem to indicate that the relation investigated in the present study does not apply in the cell line used.
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Date Issued: 1988

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Application of satellite-derived rainfall estimates to extend water resource simulation modelling in South Africa

- Sawunyama, Tendai, Hughes, Denis A

Authors: Sawunyama, Tendai , Hughes, Denis A
Date: 2008
Language: English
Type: text , Article
Identifier: vital:7089 , http://hdl.handle.net/10962/d1012419
Description: Spatially interpolated rainfall estimates from rain-gauges are widely used as input to hydrological models, but deriving accurate estimates at appropriate space and time scales remain a major problem. In South Africa there has been a gradual decrease in the number of active rain-gauges over time. Satellite-based estimates of spatial rainfall are becoming more readily available and offer a viable substitute. The paper presents the potential of using Climate Prediction Center African daily precipitation climatology (CPCAPC) satellite-based datasets (2001-2006) to drive a Pitman hydrological model which has been calibrated using gauge-based rainfall data (1920-1990). However, if two sources of rainfall data are to be used together, it is necessary to ensure that they are compatible in terms of their statistical properties. A non-linear frequency of exceedance transformation technique was used to correct the satellite data to be more consistent with historical spatial rainfall estimates. The technique generated simulation results for the 2001 to 2006 period that were greatly improved compared to the direct use of the untransformed satellite data. While there remain some further questions about the use of satellite-derived rainfall data in different parts of the country, they do seem to have the potential to contribute to extending water resource modelling into the future.
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Date Issued: 2008

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The relationship between double taxation agreements and the provisions of the South African Income Tax Act

- Stack, Elizabeth M

Authors: Stack, Elizabeth M
Date: 2014
Subjects: To be catalogued
Language: English
Type: Article
Identifier: vital:21102 , http://hdl.handle.net/10962/6384 , http://journals.co.za/content/jefs/7/2/EJC157823
Description: This article investigates the legal status of Double Taxation Agreements, and the relationship between Double Taxation Agreements, which are concluded in terms of section 108 of the Income Tax Act, and the provisions of the Income Tax Act (taking into account the provisions of the Constitution, and the national and international rules for the interpretation of statutes). An important conclusion reached was that as the Vienna Convention on the Law of Treaties represents customary international law and as such forms part of South African law, the principles contained in the treaty should be taken into account when interpreting South African legislation (including Double Taxation Agreements).The final conclusion of the research was that Double Taxation Agreements have a dual nature – forming part of domestic legislation and being classified as international agreements. The provisions of the Double Taxation Agreement should be taken as overriding any conflicting legislation in the Income Tax Act.
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Date Issued: 2014

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Sculpting with fire: celebrating ephemerality at AfrikaBurn 2015 in the Tankwa Karoo, South Africa

- Steele, John

Authors: Steele, John
Date: 2015
Language: English
Type: text , Article
Identifier: http://hdl.handle.net/11260/957 , vital:30075
Description: Land art, and some installation art, is usually aimed at relatively temporarily manipulating the surface of the earth. AfrikaBurn takes place annually in the near-desert of the Tankwa Karoo, South Africa. It is a communal event unique to Africa, and manifests as a fleeting week-long series of interventions in the natural environment, partially aimed at creating and then actively destroying free-standing public sculptures, some of which are huge and intricate. AfrikaBurn gives any one of the thousands of participants an opportunity to be inspired on any scale to generate artworks that take into account a principle that no debris whatsoever is left behind on the surface of the earth after a week-long celebration of creative energies. Unlike, for instance, an artwork built on the edge of the Indian Ocean in the Eastern Cape, where rough tidal seas would ensure gradual destruction, at AfrikaBurn, the sacrificial method of choice is controlled rapid burning, under the direction of a specified firemaster. This paper seeks to unbundle some aspects of land and installation art in Southern Africa with specific reference to AfrikaBurn 2015 events and anti-fracking initiatives. This is within a context that takes into account recognition that even seemingly durable public sculptures are subject to change and may even physically disappear with the passing of time.
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Date Issued: 2015

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Will the real custodian of natural resource management please stand up

- Shackleton, Charlie M

Authors: Shackleton, Charlie M
Date: 2009
Language: English
Type: Article
Identifier: vital:6657 , http://hdl.handle.net/10962/d1007076
Description: South Africa is the custodian of an immense wealth of biodiversity resources, and is estimated to be the third most biodiverse country in the world. At the ecosystem level this biodiversity supports the production of goods and services used by us all; water, air, soil fertility, wood, food, etc. At a more local level the harvesting of numerous natural resources provides consumptive products for millions of poor South Africans, as well as income for equally significant numbers.Consumption of and trade in these resources is the very mainstay of their well-being, and crucial in preventing deeper poverty levels. For example, despite massive improvements in the provision of electricity, most rural and a significant proportion of urban South Africans continue to use fuelwood as a key energy source for cooking (e.g. 65% of electrified households in the urban areas of Makana municipality, and 92% of households in the rural areas of Bushbuckridge); approximately 75% of the population use medicinal plants for medicinal or cultural reasons; and millions of urban and rural households make use of wild edible herbs. With such high demand for these resources, it is not unsurprising that there are large and established trade networks spanning local, regional, national and, for some resources (e.g. specific medicinal plants, mopane worms), international boundaries. The total value of this trade is unknown, and unrecorded in local or national economic or GDP statistics. It certainly equates to billions of rands per year. The direct-use and trade values are substantial and provide a cost saving to the State. Where biodiversity resources are overused or exhausted, people have to purchase alternatives, which reduces their scarce cash resources, thereby increasing their likely dependency on State welfare grants.
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Date Issued: 2009

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The need for an inland fisheries policy in South Africa : a case study of the North West Province

- Weyl, Olaf L F, Potts, Warren M, Rouhani, Q

Authors: Weyl, Olaf L F , Potts, Warren M , Rouhani, Q
Date: 2007
Language: English
Type: Article
Identifier: vital:6769 , http://hdl.handle.net/10962/d1008056
Description: In contrast to many other African countries, inland fisheries in South Africa are poorly developed and the fish populations in many of the country’s 3 000 major dams are under-utilised. While the primary purpose South Africa’s dams is to supply water for domestic and agricultural use, there has been an increasing realisation that their fish populations could make a contribution to food security through the establishment of capture fisheries. Historically, the fish in most South African dams have primarily been utilised for recreational fishing purposes, as subsistence use was criminalised by the apartheid regime in all waters except in the former homeland areas. This legacy persists as many of South Africa’s rural communities do not have a fishing tradition and there is a lack of an institutional framework to facilitate managed and sustainable access to the fish resource in inland waters. Current utilisation of many inland dams is often complicated by the existence of multiple authorities and interest groups, often with competing agendas. As a result, the economic potential of these water bodies is unknown and often grossly underutilised. Our study outlines a case study of fisheries resources in the North West Province of South Africa that could be used for the creation of income and food security for local communities through the development of subsistence, commercial, and recreational fisheries. The study identifies the lack of guidelines for the development of inland fisheries and the lack of an inland fisheries policy, both at the provincial and national level, as major bottlenecks for the sustainable development of these resources and outlines possible focal areas for intervention.
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Date Issued: 2007

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Photoinactivation of Candida albicans and Escherichia coli using aluminium phthalocyanine on gold nanoparticles

- Mthethwa, Thandekile, Nyokong, Tebello

Authors: Mthethwa, Thandekile , Nyokong, Tebello
Language: English
Type: Article
Identifier: vital:7298 , http://hdl.handle.net/10962/d1020364
Description: The conjugates of aluminium phthalocyanine (complex 1) with gold nanorods (complex 1–AuNRs) and bipyramids (complex 1–AuBPs) showed improved singlet oxygen quantum yields of 0.23 and 0.24, respectively, compared to that of complex 1 alone at 0.12. Complex 1 and its conjugates were used for the photoinactivation of fungi (C. albicans) and bacteria cells (E. coli). The Q band absorbances were the same for the Pc alone and when conjugated to AuNPs. The efficiency of these conjugates was evaluated by measuring the log reduction of the microorganisms (C. albicans and E. coli) after irradiation with visible light in the presence of photosensitizers. Aluminium phthalocyanine alone showed log 1.78 and log 2.51 reductions for C. albicans and E. coli respectively. However, the conjugates showed higher photosensitization with log 2.08 and log 3.34 for C. albicans and E. coli, respectively using 1–AuBPs. For complex 1–AuNRs log 2.53 and log 3.71 were achieved for C. albicans and E. coli respectively. The statistical analysis of the results showed that the enhanced photoinactivation observed in both microorganisms was irrespective of the shape of the nanoparticles conjugated. Photoinactivation of C. albicans was less than that of E. coli even though a higher concentration of complex 1 or its conjugates was used in C. albicans. , Original publication is available at http://dx.doi.org/10.1039/C4PP00315B , Arbortext Advanced Print Publisher 9.1.520/W Unicode , Acrobat Distiller 10.0.0 (Windows); modified using iTextSharp 5.5.1 �2000-2014 iText Group NV (AGPL-version); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)
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Gowin's Knowledge Vee and the integration of philosophy and methodology : a case study

- Fox, Roddy C

Authors: Fox, Roddy C
Date: 2007
Language: English
Type: Article
Identifier: vital:6682 , http://hdl.handle.net/10962/d1006677
Description: Universities with a strong research tradition commonly have courses or modules examining the tradition’s philosophies and methodologies to prepare their students to undertake research programmes. Recently, however, authors have called for wider debate concerning how we teach these courses and this paper is intended, in part, to make a contribution to this debate. The Research Philosophy and Methodology module examined here makes an intriguing case study because of a number of distinctive characteristics. The teaching philosophy of the module is social constructivist and it uses Gowin’s Knowledge Vee as its main heuristic device. This facilitates the construction of knowledge about philosophy and methodology in an integrated manner. The module has also been designed for both physical and human geography students at the introductory post-graduate level. There is, therefore, a second element of integration in the curriculum. Lastly, the module is predominantly web-based, being taken by distance students through the exchange agreement between Rhodes University, South Africa, and the University of Trollhättan-Uddevalla, Sweden. Evidence from reflective exercises shows that the learners’ understanding of research and the research process has deepened considerably through using Gowin’s Vee. Furthermore, using the Knowledge Vee in the web-based context has facilitated the integrative aspects of the module.
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Date Issued: 2007

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The geology and geochemistry of the Palaeoproterozoic Makganyene diamictite

- Polteau, S, Moore, John M, Tsikos, Harilaos

Authors: Polteau, S , Moore, John M , Tsikos, Harilaos
Date: 2006
Language: English
Type: Article
Identifier: vital:6740 , http://hdl.handle.net/10962/d1007556
Description: The Palaeoproterozoic Earth experienced a global glacial event at 2400 Ma that occurred during the transitional period from anoxic to aerobic conditions in the atmosphere and oceans. The Transvaal Supergroup in the Griqualand West Basin, South Africa, hosts glacial deposits and associated major iron and manganese deposits that are apparently related to these global changes. The focus of this study is to assess the stratigraphy and geochemistry of the glaciogenic Makganyene Formation, in order to constrain its palaeoenvironmental settings. The Makganyene Formation forms the base of the Postmasburg Group and has been regarded as resting on an erosive regional unconformity throughout the Northern Cape Province. Systematic regional field observations and regional mapping carried out during this study demonstrate that this stratigraphic relationship is not universal. The Makganyene Formation is, in fact, conformable with underlying formations of the Koegas Subgroup in the deep southern Prieska basin and rests on an unconformity only on the shallow Ghaap platform to the north-east. The Makganyene Formation displays lateral facies changes that reflect the palaeogeography of the study area, and the advance and retreat of ice sheets/shelves. Geochemical investigations of glacial strata of the Makganyene Formation demonstrate that underlying banded iron formations of the Transvaal Supergroup acted as the main clastic source for the diamictite detritus. Geographic variations in bulk composition of the diamictites correlate well with field observations, and show that sorting processes were controlled largely by the morphology of the palaeobasin. Carbon isotope results emphasize the transitional nature of the Makganyene Formation in terms of the environmental conditions that resulted in widespread global glaciation in the Palaeoproterozoic. On the basis of the above geological evidence, it is proposed that the Transvaal Supergroup in the Northern Cape Province represents a continuous depositional event that lasted approximately 250 Ma and hence provides a unique opportunity for assessing the transitional changes experienced by the Palaeoproterozoic Earth.
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Date Issued: 2006

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Music in a blue haze

- Lautre, Maxine

Authors: Lautre, Maxine
Subjects: McGregor, Chris--1936-1990 , Jazz , Jazz musicians , Blue Notes (Musical group : South Africa) , Pukwana, Dudu
Language: English
Type: Article
Identifier: vital:13587 , http://hdl.handle.net/10962/d1009492 , McGregor, Chris--1936-1990 , Jazz , Jazz musicians , Blue Notes (Musical group : South Africa) , Pukwana, Dudu
Description: Photocopied article from the newspaper The Star about a concert by Chris McGregor and the Blue Notes at the Dorkay House, at Eloff Street in Johannesburg, South Africa. There is a picture of Chris McGregor playing piano with Dudu Pukwana playing saxophone, with this article.
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