A review of estuarine ichthyology in South Africa over the past 50 years
- Authors: Whitfield, Alan K
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:7155 , http://hdl.handle.net/10962/d1011873
- Description: Progress in South African estuarine ichthyology between 1946 and 1995 is reviewed. The early estuary surveys of the 1950s and 1960s resulted in the compilation of species lists for individual systems, but contained very little biological or ecological information on fishes. These surveys were superseded by both autecological and synecological studies in the 1970s and 1980s, which yielded descriptive and process-orientated information on a wide variety of species. Estuarine research during the 1990s has focused increasingly at the community level, with several review papers on the life-history styles of groups of estuarine-associated fishes being published. The last decade has also seen the departure of a number of senior estuarine ichthyologists from the field. This decline in available expertise has coincided with increased demand for ichthyological information to be used in decision support systems for the wise management and conservation of estuaries. It is suggested that these demands be seen as a challenge, with studies being directed towards providing the type of information needed for the maintenance of vital ecological processes within these systems.
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Bleak future for multi-party elections in Kenya
- Authors: Fox, Roddy C
- Date: 1996
- Language: English
- Type: Article
- Identifier: vital:6683 , http://hdl.handle.net/10962/d1006681
- Description: With attention turning towards Kenya's second multi-party elections, due to be held before the end of 1997, it is imperative to look back to the flaws in the system which helped deliver President Daniel arap Moi and the Kenya African National Union (KANU) their victories in 1992. At present there is no sign of these defects being eradicated and the creation of new districts since then has demonstrated the Government's intention of enhancing an already biased structure. The underlying distribution of tribes and ethnic groups has had a fundamental impact on the electoral geography of Kenya, since they have controlled the delimitation of both the parliamentary constituencies and the administrative machinery of the whole country.
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Controls on channel form and channel change in the Bell River, Eastern Cape, South Africa
- Authors: Rowntree, Kate M , Dollar, Evan S J
- Date: 1996
- Language: English
- Type: Article
- Identifier: vital:6723 , http://hdl.handle.net/10962/d1006801
- Description: Channel instability has occurred in the Bell River in the form of meander cutoffs, incipient meander cutoffs, and general channel instability. This paper examines the incidence of channel instability in relation to the spatial variability of factors controlling channel form. The locations of channel change were mapped from aerial photographs for a 40 year period. Channel form characteristics were measured over a 17 km stretch of channel. Data collected from this stretch included pattern, width, depth, form ratio, channel gradient, particle-size distribution of bed and bank materials and riparian vegetation. Results indicate that the two primary spatial controls on channel form and pattern are riparian vegetation and bed-material size. Evidence indicates that narrow stable stretches are associated with finer bed-material and relatively high levels of riparian vegetation. Riparian vegetation increases bank stability and reduces channel cross-section, thereby inducing stability at flows less than bankfull. However, at flows greater than bankfull, reduced channel capacity results in more frequent flooding which may ultimately lead to channel avulsion. Wider, unstable channels are associated with larger calibre bed material and relatively less riparian vegetation. Predicted threshold slopes for braiding have indicated that most reaches in the Bell river are close to or above the threshold slope for braiding. Since riparian vegetation serves to increase bank stability, steeper threshold slopes are required for braiding in channels with high vegetation density Recent incidences of channel instability have been identified as occurring in the transitional zone between the upper, coarser reach and lower, finer channel reach.
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Fifty years of ichthyology in Grahamstown
- Authors: Skelton, Paul H
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:7138 , http://hdl.handle.net/10962/d1011816
- Description: In July 1946, the fledgling Council for Scientific and Industrial Research (CSIR) awarded Dr J.L.B. (James Leonard Brierley) Smith of Rhodes University College a research fellowship of £800 to enable him to devote his energies to ichthyology. The university responded by providing accommodation, equipment and appointing Smith a research professor. These actions marked the beginning of what has become a major academic development in Grahamstown as represented by the J.L.B. Smith Institute of Ichthyology, the Department of Ichthyology and Fisheries Science (DIFS), and the Freshwater Fish Section at the Albany Museum. At present more than 40 people are employed in one way or other in these organizations, more than 20 of them professionals, in addition to whom there are 41 postgraduate students currently studying ichthyology or fisheries science through DIFS at Rhodes University. Altogether this represents a concentration of ichthyological expertise probably unmatched anywhere else in the world. It is opportune therefore to highlight a few of the more significant milestones in the history of ichthyology in Grahamstown and so illuminate some of the key factors behind this achievement.
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Nicknames as sex-role stereotypes
- Authors: De Klerk, Vivian A , Bosch, Agnes Barbara
- Date: 1996
- Language: English
- Type: Article
- Identifier: vital:6134 , http://hdl.handle.net/10962/d1011586
- Description: Nicknames are powerful indicators of attitudes towards gender categories and because of their transient and optional nature, it has been argued that they are more likely to show a closer relationship to ongoing trends in the culture and society than other more fixed parts of the language E. B. Phillips (1990) ["Nicknames and Sex Role Stereotypes," Sex Roles, Vol. 23, pp. 281-289]. This study reports on a survey of nickname usage among a group of South African adolescents from mixed socioeconomic backgrounds (approximately 25% other than white) in an attempt to explicate gender-linked trends in frequency of occurrence, usage and attitudes to such special names. It reveals that conventions regarding nickname coinage and usage are intimately connected to the gender of bearers and users, and that more males have nicknames and coin them than females; it also shows significant sex-linked differences in the linguistic sources and users of nicknames, and reveals a greater tendency for female nicknames to function as indicators of affection rather than for humorous or critical effect. It could be argued that these trends could be linked to the nurturing and nurtured role of females in society, and to the differences in social power generally between males and females.
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Role of percutaneous penetration enhancers
- Authors: Walker, Roderick B , Smith, Eric W
- Date: 1996
- Language: English
- Type: text , Article
- Identifier: vital:6446 , http://hdl.handle.net/10962/d1006633
- Description: It is clear that scientists are now only beginning to comprehend the complexity of transdermal drug delivery. Elucidation of the biochemical composition and functioning of the intrinsic diffusional barrier of the stratum corneum has prompted investigation of chemical and physical means of enhancing the percutaneous penetration of poorly absorbed drugs. Chemical enhancers that aid absorption of co-administered moieties are currently believed to improve solubility within the stratum corneum or increase lipid fluidity of the intracellular bilayers. Alternatively,the use of ionto- or phonophoresis may facilitate the absorption of some drug molecules by physical alteration of the barrier. The role of penetration enhancer inclusion in topical formulations has been well documented and will undoubtedly, in the future, permit the delivery of broader classes of drugs through the stratum corneum.
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The use of wood ash for the protection of stored cowpea seed (Vigna unguiculata (L.) Walp.) against Bruchidae (Coleoptera)
- Authors: Katanga Apuuli, J , Villet, Martin H
- Date: 1996
- Language: English
- Type: Article
- Identifier: vital:6864 , http://hdl.handle.net/10962/d1011196
- Description: Dry wood-ash has been reported to provide effective, cheap and safe control of several pests of stored seeds by providing mechanical protection, especially if it is thoroughly mixed with the seed. Mixtures of seed and either clays, ash, talc, or sand are among the earliest recommendations for controlling bruchids in beans (Metcalf 1917; Headlee 1924; Subramanian 1935; Deay & Amos 1936; Lever 1941). Such use of ash has been reported on subsistence farms in Uganda (Davies 1970). However, little is known of the actual ratios of ash and beans needed for effective protection, or of the mechanism of protection. These issues motivated this investigation.
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