28 research outputs found

    Occurrence and Detection of Killer Yeasts on Chenin Blanc Grapes and Grape Skins

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    Two hundred and thirty killer yeast strains were selectively isolated from Chenin blanc grapes and grape skins collected from six wineries. The killer yeasts were divided into nine groups based on their colony morphology and colour on modified Wallerstein laboratory nutrient agar. All strains fermented Chenin blanc grape must (pH 3,5; 40 mg/ I free SO, and 5% (v/v) ethanol) at l4°C. Existing techniques in which methylene blue are used were evaluated to detect killer yeasts, to determine interactions between different killer phenotypes, and to determine the sensitivity of commercial strains to the killer toxins

    A scanning electron-microscope examination of the scolex of Houttuynia struthionis

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    A scanning electron-microscope examination of the scolex of Houttuynia struthionis, a cestode of ostriches, was undertaken in order to study its surface structure. The scolex differs from those of other subfamilies in the family Davaineidae in that it does not have scale-like spines covering the base of the rostellum. Instead, the base is covered with small hooks resembling the larger rostellar hooks in shape.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    Comparisons of Meso-Scale Air Pollution Dispersion Modelling of S02, N02 and 03 Using Regional-Scale Monitoring Results

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    Results of a regional-scale monitoring campaign were compared with two meso-scale to sub-continental modelling studies, for S02 and N02 and 03 respectively (Fourie, 2006, Zunckel et al., 2006, van Tienhoven et al., 2006, Van Tienhoven and Zunckel, 2004). However, a direct validation of the monitored results with modelled results could not be carried out, as available modelling studies dealt with different periods from the monitoring study. For this study, three monitoring sites were selected for comparison with modelling results. These sites were strategically selected to be representative of the entire region. Site Elandsfontein in the centre of the industrial Highveld, site Amersfoort, downwind from the central pollution source region and site Louis Trichardt, a remote site. Sulphur, nitrogen and ozone species comparisons were considered in turn. The comparisons were carried out for equivalent annual (and seasonal) cycles. The compa risons produced mixed results. For sulphur and nitrogen species in most cases, depending on site and season, modelling results ranged between significant underestimates to overestimates. Ozone modelling almost always overestimated the concentrations compared to the measured results. Despite several limiting factors, constraining the reliability of the comparisons between the modelled and measured results, they were important as the distribution of the gases showed patterns that imply understanding of the source and fate of these pollutants. The uncertainty in the magnitude of the model inaccuracies as well as margin of error of the measured data remained. Thus a modelling validation is recommended using the concurrent period with fewer uncertainties

    A critical engagement with theological education in Africa

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    The higher education landscape has arguably become one of the most arduous to traverse. More so in the African context, where a host of variables continiously challenge educators to reflect critically on their philosophies and practices as they engage an ever-changing audience. In this book, a critical engagement with theological education in Africa is offered. As the book originates from South Africa, it is presented as a South African perspective, although contributors are situated accross the African continent and abroad. The common denominator is that all contributers are, in some way or another, invested in theological education in Africa. The main contribution of this collaborative work is to be sought in the insights it offers on four main areas of theological education: A historical and current orientation on theological edcuation in Africa, some paradigm shifts in theological education in Africa, ministerial formation needs versus theological education challenges, and a critical reflection on elective models and methods. The book presents the original and innovative research of scholars for fellow scholars involved in theological higher education as it is grounded in the respective fields of interest of each contributor. It contributes to a better understanding of the complex African theological higher education landscape that is also mindful of post-COVID-19 realities. Methodologically the work draws on a combination of methods, including literature studies, empirical work, and in some cases sectional offerings from doctoral studies, as indicated in the various chapters

    A critical engagement with theological education in Africa

    Get PDF
    The higher education landscape has arguably become one of the most arduous to traverse. More so in the African context, where a host of variables continiously challenge educators to reflect critically on their philosophies and practices as they engage an ever-changing audience. In this book, a critical engagement with theological education in Africa is offered. As the book originates from South Africa, it is presented as a South African perspective, although contributors are situated accross the African continent and abroad. The common denominator is that all contributers are, in some way or another, invested in theological education in Africa. The main contribution of this collaborative work is to be sought in the insights it offers on four main areas of theological education: A historical and current orientation on theological edcuation in Africa, some paradigm shifts in theological education in Africa, ministerial formation needs versus theological education challenges, and a critical reflection on elective models and methods. The book presents the original and innovative research of scholars for fellow scholars involved in theological higher education as it is grounded in the respective fields of interest of each contributor. It contributes to a better understanding of the complex African theological higher education landscape that is also mindful of post-COVID-19 realities. Methodologically the work draws on a combination of methods, including literature studies, empirical work, and in some cases sectional offerings from doctoral studies, as indicated in the various chapters

    Phenotypic and genetic aspects of production in the Dohne Merino. IV. The influence of age of the ewe on production lambs

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    To determine the influence of the age of the ewe on characteristics such as body mass, greasy fleece mass, clean fleece mass, fiber diameter and staple length the data obtained from 500 ewes born between 1970 and 1979 was used. Their body mass at mating increased from 55 kg to 61 kg between the ages of 1½ and 5½ years, after which it declined steeply to the age of 9½ years. Greasy fleece mass increased up to the age of 3½ years (4.53 kg) and then steadily declined up to the age of 9½ years (2.82 kg). In contrast, maximum clean fleece mass was achieved at the age of 1½ years (2.94 kg). Clean fleece mass declined by 17.5% from 1½ to 9½ years of age. Fiber diameter increased from 21.4 to 23.3 microns between the age of 1½ and 7½ years after which it declined up to the age of 9½ years. The staple length was 92.2 mm at 1½ years of age followed by a linear decline up to 9½ years of age

    Animal genetic resources in Africa

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