1,410 research outputs found
André Pretorius Collection index
No full textThis index describes the Andre Pretorius collection which consists of material collected by André Pretorius (1935-2006), author, photographer and conservationist. The material pertains mainly to the areas in the Western, Northern and Eastern Cape. The collection contains photographs ; newspaper clippings ; articles ; brochures ; correspondence contained in 3 filing cabinets (4 drawers each)
Johannes Pretorius, die Stamvader van die Pretoriusse van Suid-Afrika, se jare op Mauritius, 1666-1669: I
No full textThe Mauritius years of Johannes Pretorius, progenitor of the Pretorius family of South Africa (1666-1669). The Mascarene Islands of Reunion (Bourbon), Mauritius and Rodrigues were discovered in 1513 by the Portuguese navigator, Don Pedro Mascarenha. Mauritius was initially called Ilha da Cirnos (Swan Island) after the swan-like but now long extinct dodo birds. The first settlers were Dutch seamen under Admiral Wybrandt van Warwyk who landed on the island in 1598 and named it Mauritius in honour of their stadholder Maurice of Orange (Nassau). The island which was strategically situated between the Cape and Batavia (Jakarta) in the East Indies was occupied by the Dutch East India Company for the first time in 1638. The main reasons for this occupation were firstly to avoid the menacing Portuguese presence along the East Coast of Africa and secondly the abundance of much sought after ebony on the island. Although the Dutch abandoned the island in 1658, the Dutch East India Company informed Jan van Riebeeck in 1657 that henceforth Mauritius would be administered by the Cape Council of Policy. This led to the second Dutch settlement which lasted for nearly half a century - from 1664 till 1710 - and forget the historic link between the Cape Dutch Settlement and the distant island of Mauritius. In 1666, two years after the second Dutch occupation, Johannes Pretorius, European ancestor of the South African Pretorius family was sent to Mauritius by the Council of Policy at the Cape. This account of his departure from the Netherlands, his arrival at the Cape, his subsequent departure and three years\u27 stay on Mauritius is set in the prevailing Cape and Mauritian history and has been compiled from South African and Dutch archivalia.
Die skilderagtige, gedeeltelik tropiese en vrugbare eiland van Mauritius in die lndiese Oseaan is in 1513 deur die Portugese ontdek. Hulle het dit die Swan-eiland (Ilha da Cirnos) genoem, vermoedelik vanwee die groot en nou uitgestorwe oervoels, die dodo\u27s, wat destyds op die strande gevind is. Die eiland is een van die Maskarene-eilande wat ook insluit Reunion (Bourbon) en Rodrigues. Hulle is vernoem na die Portugese seevaarder Don Pedro Mascarenhas wat die eilande in 1513 ontdek het. Gelukkig was die ou Hollandse seevaarders van die sewentiende en agtiende eeu baie trots op hulle meer geloofwaardige dade. Tereg ook so want vir hierdie klein Europese volk was daar soms meer Nederlandse skepe ter see as die hele res van Europa. Gevolglik is elke seereis na die Ooste opgeteken en kan daar vandag in Den Haag uit hierdie rykste versameling van maritieme geskiedenis ter wereld ook die vroee geskiedenis van Mauritius gevind word. Hieruit is bekend dat die Hollanders in 1598 op die eiland geland en dit na hulle stadhouer Maurits van Oranje (Nassau), ook die seun van Willem van Oranje (Nassau), vernoem bet. Teen 1638 het die Verenigde Oos-Indiese Companje (V.O.C.) besluit om die eiland vir die eerste keer te beset. Dit is strategies en gunstig ongeveer halfweg tussen die Kaap en Batavia (Jakarta) op pad na Oos-Indie gelee. Die vernaamste redes vir die besetting was om die Portugese besetting van die Oos-Afrikaanse kus te vermy en die groot voorrade gesogte ebbehout op die eiland. Alhoewel hierdie eerste besetting in 1658 beeindig is, het die V.O.C. in 1657 reeds vir Jan van Riebeeck in kennis gestel dat beplan word om Mauritius onder die Kaapse bestuur te plaas. \u27n Minder bekende maar nietemin wetenswaardige geskiedkundige tydperk het hierdeur tussen die Kaapse nedersetting en die afgelee Mauritius tydens die daaropvolgende tweede Nederlandse besetting van Mauritius tussen 1664 en 1710, ontstaan. Ten spyte van heelwat inligting oor die Europese herkoms en familiegeskiedenis van Johannes Pretorius, stamvader van die Pretoriusse van Suid-Afrika, bestaan daar tot dusver geen volledige verhaal oor sy vertrek uit Holland tot en met sy terugkeer na die Kaap na \u27n verblyf van ongeveer drie jaar op Mauritius nie. Daar bestaan selfs onsekerheid of hy eers die Kaap aangedoen het voor sy aankoms op Mauritius. Wat wel bekend is, en waarvan kortliks melding gemaak word, is dat hy op Mauritius as sieketrooster en sekunde in die diens van die V.O.C. was. Dr. C. Graham Botha, \u27n voormalige hoofargivaris, het vermoedelik eerste in \u27n tot dusver ongepubliseerde artikel, "Een Genealogiese Studie: Die familie Pretorius", kortliks na Johannes Pretorius se verblyf op Mauritius verwys. Wat volg is \u27n rekonstruksie van die ervaring van Johannes Pretorius sedert sy vertrek in Desember 1665 uit Holland tot en met sy terugkeer in 1669 na die Kaap
Assimilable nitrogen utilisation and production of volatile and non-volatile compounds in chemically defined medium by Saccharomyces cerevisiae wine yeasts
No full textSurveys conducted worldwide have shown that a significant proportion of grape musts are suboptimal for yeast nutrients, especially assimilable nitrogen. Nitrogen deficiencies are linked to slow and stuck fermentations and sulphidic off-flavour formation. Nitrogen supplementation of grape musts has become common practice; however, almost no information is available on the effects of nitrogen supplementation on wine flavour. In this study, the effect of ammonium supplementation of a synthetic medium over a wide range of nitrogen values on the production of volatile and non-volatile compounds by two high-nitrogen-demand wine fermentation strains of Saccharomyces cerevisiae was determined. To facilitate this investigation, a simplified chemically defined medium that resembles the nutrient composition of grape juice was used. Analysis of variance revealed that ammonium supplementation had significant effects on the concentration of residual sugar, L-malic acid, acetic acid and glycerol but not the ethanol concentration. While choice of yeast strain significantly affected half of the aroma compounds measured, nitrogen concentrations affected 23 compounds, including medium-chain alcohols and fatty acids and their esters. Principal component analysis showed that branched-chain fatty acids and their esters were associated with low nitrogen concentrations, whereas medium-chain fatty esters and acetic acid were associated with high nitrogen concentrations.M. Vilanova, M. Ugliano, C. Varela, T. Siebert, I. S. Pretorius and P. A. Henschk
Responsible Investment: A Vehicle for Environmentally Sustainable Economic Growth in South Africa
No full textThis paper explores whether any investment products or strategies in South Africa take environmental sustainability into account. By looking at how environmental, social, and governance (ESG) criteria are used in investment decision making, we found that most socially-responsible investment products and responsible investment strategies largely focus on infrastructure, development, and black economic empowerment. Environmental criteria do not yet receive comparable attention from South African asset managers and owners. Mainstreaming responsible investment principles will need to come from either an increase in demand for such practices by asset owners or from company positions on ESG issues.responsible investment, socially responsible investment, pension funds, asset managers, screening, active share ownership
Combating alcohol abuse: one household at a time
No full textAlcohol misuse remains a serious problem among South Africans, as almost a third of heads of households in informal urban areas who participated in SANHANES-I regarded alcohol misuse as a serious or very serious problem. Liezelle Pretorius, Leickness Simbayi and Demetre Labadarios report on the findings
Fermenting knowledge: the history of winemaking, science and yeast research
No full textLink to a related website: http://europepmc.org/articles/pmc2999870?pdf=render, Open Access via UnpaywallIn the second article of the ‘Food and Science' series, Paul Chambers and Isak Pretorius explain the central role of yeast in wine making and how biotechnology can contribute to improving the quality of wine
Observational constraints on the evolution of cataclysmic variable stars
No full textI provide observational constraints on the size and period distribution of the Galactic cataclysmic variable (CV) population, and derive the implications that these constraints have for the theory of CV evolution. The results are based on quantitative modelling applied to three observational CV samples, two of which are newly constructed here. Large differences between the size and other properties of the known sample of CVs and the predictions of the theory of binary star evolution have long been recognized. However, because all existing observational CV samples suffer from strong selection effects, observational biases, must be taken into account before it is possible to tell whether there are real inconsistencies. In order to address this, I implement a Monte Carlo method to model selection effects in observed CV samples, and make a new measurement of the space density of CVs. I illustrate the effects of the biases that are introduced by several of the most common observational strategies for identifying CVs. Also, by simulating the selection criteria of the Palomar-Green (PG) Survey, I show that selection effects cannot reconcile the relative sizes of the long- and short-period CV populations predicted by standard CV evolution theory with the observed sample. k The selection criteria used to define most CV samples (including the PG sample) discriminate heavily against the discovery of intrinsically faint, short-period systems. The situation can be improved by selecting systems for the presence of emission lines; I have therefore constructed a homogeneous new sample of 17 CVs, selected on the basis of Ha emission from the AAO/UKST SuperCOSMOS Ha Survey (SHS). I present observations of the CVs discovered in this search, and use the sample to constrain the properties of the intrinsic CV population. I show that even very generous allowance for selection effects is not sufficient to reconcile the ratio of short- to long-period CVs predicted by standard CV evolution theory with the observed sample, confirming the result based on the PG survey. The most likely implication is that short-period systems evolve faster than predicted by the disrupted magnetic braking model. This would require that an angular momentum loss mechanism besides gravitational radiation acts on CVs with orbital periods below the period gap. To bring the model into agreement with observations, the rate of angular momentum loss below the period gap must be increased by a factor of at least 3, unless the model also overestimates the angular momentum loss rate of long-period CVs. In order to constrain the size of the Galactic CV population, I construct a small, but purely X-ray flux-limited sample of CVs, using the ROSAT North Ecliptic Pole (NEP) survey. The sample includes only 4 systems, 2 of which are new discoveries. Orbital periods are measured for both these systems from time-resolved spectroscopy, and the distances of all the CVs in this sample are estimated. The space density of the CV population represented by the sample is l.lij)!? x 10~5pc~3. I also place upper limits on the space density of any population of CVs too faint to be included in the NEP survey—if the overall space density of CVs is as high as 2 x 10~4 pc~3 (as has been predicted theoretically), the vast majority of CVs must have X-ray luminosities below ~ 2 x 1029ergs~1.</p
Principal component analysis applied to Fourier transform infrared spectroscopy for the design of calibration sets for glycerol prediction models in wine and for the detection and classification of outlier samples
No full textHelene H. Nieuwoudt, Bernard A. Prior, Isak S. Pretorius, Marena Manley, and Florian F. Baue
An H?-selected sample of cataclysmic variables – I. Observations of newly discovered systems
No full textStrong selection effects are present in observational samples of cataclysmic variables (CVs), complicating comparisons to theoretical predictions. The selection criteria used to define most CV samples discriminate heavily against the discovery of short-period, intrinsically faint systems. The situation can be improved by selecting CVs for the presence of emission lines. For this reason, we have constructed a homogeneous sample of CVs selected on the basis of H? emission. We present discovery observations of the 14 CVs and two additional CV candidates found in this search. The orbital periods of 11 of the new CVs were measured; all are above 3 h. There are two eclipsing systems in the sample, and one in which we observed a quasi-periodic modulation on a ?1000 s time-scale. We also detect the secondary star in the spectrum of one system, and measure its spectral type. Several of the new CVs have the spectroscopic appearance of nova-like variables, and a few display what may be SW Sex star behaviour. In a companion paper, we discuss the implications of this new sample for CV evolution
Multiple object agreement morphemes in Setswana: a computational approach
No full textSetswana is an agglutinative language where prefixes and suffixes are extensively used
in the formation of words. Words such as verbs, pronouns, adjectives and so on, which have a
grammatical relationship with nouns in sentences, demonstrate agreement with such nouns by
means of agreement morphemes. In certain instances verbs in Setswana sentences may take two
objects. Both of these objects may be represented in the verb by object agreement morphemes.
The result is that two object agreement morphemes may be prefixed to the verb. While the
morphemes of the verb are presented systematically in Setswana grammars, the occurrence of
multiple object agreement morphemes has received limited attention in the literature on Setswana
linguistics. Similarly, this phenomenon has not yet been investigated from a computational morphological
point of view.
This article reports on (i) an example-based investigation towards a better and more complete
understanding of the phenomenon of multiple object agreement morphemes as they appear in
Setswana verbs, (ii) the modelling of these morphemes in an existing finite state tokeniser and
computational morphological analyser for Setswana, and (iii) the novel role that a morphological
analyser and its guesser variant can play in a corpus-based investigation of the phenomenon under
discussionhttp://www.tandfonline.com/doi/abs/10.2989/16073614.2012.73759
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