ABSTRACT In this paper, faces were employed as the only control means of right of entrance and usage of information on the super–highway. Principal Component Analysis (PCA) and Discrete Cosine Transform (DCT) algorithms were employed as our basis of comparison. An assessment of both algorithms was considered, it was discovered that PCA proved to be a better algorithm for access control and recognition system because of its very high average percentage of rightly classified faces (90.43%) a...
ABSTRACT Maize and soyabean are among the staples in the world. Their sustainable production through the use of synthetic fertilizer causes soil degradation and ground water contamination. An alternative means of boosting and sustaining the production of these staples through the use of rhizobium and mycorrhiza have been reported but there are contradictory reports on interactions between the two organisms. Therefore, the objective of this study was to assess the influence ofRhizobium japoni...
ABSTRACT Thermodynamic data is made use of in calculating fraction of metal solidified in solidification simulation. However, thermodynamic data for many industrial alloys in their solidification ranges are not available for most practicing engineers. It is thus desirable to develop reliable equations that can be used in calculating fraction of metal solidified for solidification simulation. This work has developed an equation to calculate fraction of metal solidified for AlSi7Mg alloy solid...
ABSTRACT The aquatic weeds on the Westlake wetland at Zandvlei (Cape Town, South Africa) were investigated in terms of their detrimental effects, and the biotic and abiotic conditions associated with their nuisance growth. Eichhornia crassipes was the most problematic of the weeds, both from a human perspective and in its effect on the system, and it appears to out-compete the initially more abundant Ceratophyllum demersum and Azolla filiculoides after disturbances such as clearing and floo...
ABSTRACT On the basisl of herbarium, living and pickled material the morphology and systematics of Psilocaulon N. E. Brown sensu Ihlenfeldt ~ Bittrich is investigated. Thirteen species {including one insufficiently known species) are recognized: ' P. articulatum, PI· bicorne, P. coriarium, P. dimorphum, P. dinteri, P. foliosum, P. gessertianum, P. granulicaule, P. junceum, P. leptafthron, P. parviflorum, P. sal.icornioides, P. subnodosum. Species of Mesembryanthemum, Prenia, Brownanthus, ...
ABSTRACT Novel Synthetic Routes to 14(3,17(3-Propano and Cyclopenta[14,15] 19-Norsteroids Pia Gail Mountford, Chemistry Department, University of Cape Town, Rondebosch 7700, February 1995 An efficient synthetic strategy for the stereoselective introduction of a 14(3-allyl group to estrone 3-methyl ether has been developed. The approach involves regio- and stereoselective Diets-Alder cycloaddition of acrolein to 3-methoxyestra-1,3,5(10),14,16- pentaen-17-yl acetate. Hydride reduction of the f...
ABSTRACT Some of the physiological and ultrastructural changes occurring during the dehydration and rehydration of the "resurrection" plant Myrothamnus flabellifolia were investigated. The changes in stem and leaf orientation through angles greater than 45 degrees were recorded, and these changes, along with the change in adaxial leaf surface pigmentation, may serve to limit bright-light and/or thermal damage to these plants. M flabellifolia retained more than 70% total chlorophyll content...
The Effect of Smoke Treatment on the Germination on Four Species of Mesembryanthemum :Some Preliminary Observations
ABSTRACT The seaweeds of the Namibian coast have received little attention from researchers despite the fact that there is a successful industry based on seaweed exploitation. Beach cast Graci/aria verrucosa (Hudson) Papenfuss is collected (9000-15000 t (wet) y-1) in the Luderitz area for the production of agar, Laminaria schinzii Foslie was harvested for a short period from April 1987 to March 1989 and there is an increasing interest in utilizing other seaweed species on the coast. The natu...
ABSTRACT Aspects of the feeding strategies and digestive invertebrate-microbial interactions of two saltmarsh thalassinid detritivores, the mudprawn Upogebia africana (Ortmann) and the sandprawn Callianassa kraussi Stebbing were examined. Resources available in their respective habitats were investigated together with the feeding apparatus, diet and digestive enzymes necessary for hydrolysis of refractory compounds of detritus. U. africana inhabits the upper reaches of Langebaan lagoon (Geel...
Abstract Cycloadditions of steroidal 14,16-dienes with ketene equivalents were investigated, as routes to estradiol and estriol analogues. The cycloadduct of 3-methoxyestra- 1,3,5(10), 14,16-pentaen-17-yl acetate and 2-chloroacrylonitrile underwent an unprecedented tandem rearrangement, on attempted alkaline hydrolysis to the corresponding ketone. This product, obtained in ca. 90% yield, was formulated as (161R)-3-methoxy-17-oxo-158,161-cyclo-14,168-ethano-148-estra-1,3,5(10)-triene-16L carbo...
ABSTRACT The poor response of some plant species, e.g. wheat, to ammonium nutrition has been attributed to a diversion of carbon allocation from structural material for root extension to functions associated with the assimilation and translocation of ammonium in the root. The aim of this research was to investigate carbon allocation in response to ammonium or nitrate nutrition in wheat, an ammonium intolerant species, and maize, which exhibits ammonium tolerance. Experiments were · carried ...
Abstract The structures of some non-cellulosic S-Q-Glycans from three plant sources have been investigated and each was found to be characterised by linked D-pyranosyl a main chain consisting of S-(1-44)- sugars. The polysaccharides were, however, different in structural features in a manner apparently related to their respective locations within the organs of the plants concerned. The polysaccharides were isolated and purified using standard fractionation methods including chromatographic te...
ABSTRACT A regional study of highly metamorphosed supracrustal rocks was undertaken in the western portions of the Namaqualand Metamorphic Complex. The study area was essentially restricted to a north - south section some 50 kilometres wide and 220 kilometres long . Eight east-west-trending belts of supracrustal rocks were examined, together with several smaller paragneiss remnants , in an area dominated by quartzo - feldspathic gneisses of granitic composition. The supracrustal rocks were c...
Abstract The seed that eventually gave birth to this thesis was planted in August, 1975 when, during a cruise of the Research Vessel Meiring Naude the existence of deep-sea cyclonic vortices in the South Western Indian Ocean was discovered. Little was it realised during that small, fortuitous beginning in 1975 that the study would develop into the first detailed physical oceanographic investigation of the Mozambique Ridge and adjacent Mozambique Basin areas. It could also not be foreseen tha...