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Baman

- Sali Sidibe (composition, lyrics, lead vocal), Boubacar Kane (djembe), Aminata Diabate, Fatim Sissoko (backing vocals), Rakesh Toure (keyboards), Mamadou Coulibaly (N'Bolon), Harouna Samake (N'goni), Zoumana Tereka (Violin), Samba Dioakite (Balafon), Sterns Africa label

Bioaccumulation of metal cations by yeast and yeast cell components

- Brady, Dean

  • Authors: Brady, Dean
  • Date: 1993
  • Subjects: Yeast , Yeast fungi -- Biotechnology , Cations , Metal ions
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4046 , http://hdl.handle.net/10962/d1004107 , Yeast , Yeast fungi -- Biotechnology , Cations , Metal ions
  • Description: The aim of the project was to determine whether a by-product of industrial fermentations, Saccharomyces cerevisiae, could be utilized to bioaccumulate heavy metal cations and to partially define the mechanism of accumulation. S. cerevisiae cells were found to be capable of accumulating Cu²⁺in a manner that was proportional to the external Cu²⁺ concentration and inversely proportional to the concentration of biomass. The accumulation process was only minimally affected by temperature variations between 5 and 40°C or high ambient concentrations of sodium chloride. The accumulation process was however considerably affected by variations in pH, bioaccumulation being most efficient at pH 5 - 9 but becoming rapidly less so at either extreme of pH. Selection for copper resistant or tolerant yeast diminished the yeast's capacity for Cu²⁺ accumulation. For this and other reasons the development of heavy metal tolerance in yeasts was deemed to be generally counterproductive to heavy metal bioaccumulation. The yeast biomass was also capable of accumulating other heavy metal cations such as c0²⁺ or Cd²⁺. The yeast biomass could be harvested after bioaccumulation by tangential filtration methods, or alternatively could be packed into hollow fibre microfilter membrane cartridges and used as a fixed-bed bioaccumulator. By immobilizing the yeast in polyacrylamide gel and packing this material into columns, cu²⁺, C0²⁺ or Cd²⁺ could be removed from influent aqueous solutions yielding effluents with no detectable heavy metal, until breakthrough point was reached. This capacity was hypothesized to be a function of numerous "theoretical plates of equilibrium" within the column. The immobilized biomass could be eluted with EDTA and recycled for further bioaccumulation processes with minor loss of bioaccumulation capacity. Yeast cells were fractionated to permit identification of the major cell fractions and molecular components responsible for metal binding. Isolation of the yeast cell walls permitted investigation of their role in heavy metal accumulation. Although the amino groups of chitosan and proteins, the carboxyl groups of proteins, and the phosphate groups of phosphomannans were found to be efficient groups for the accumulation of copper, the less effective hydroxyl groups of the carbohydrate polymers (glucans and mannans) had a similar overall capacity for copper accumulation owing to their predominance in the yeast cell wall. The outer (protein-mannan) layer of the yeast cell wall was found to be a better Cu²⁺ chelator than the inner (chitinglucan) layer. It appeared that the physical condition of the cell wall may be more important than the individual macromolecular components of the cell wall in metal accumulation. It was apparent that the cell wall was the major, if not the sole contributor to heavy metal accumulation at low ambient heavy metal concentrations. At higher ambient metal concentrations the cytosol and vacuole become involved in bioaccumulation. Copper and other metals caused rapid loss of 70% of the intracellular potassium, implying permeation of the plasma membrane. This was followed by a slower "leakage" of magnesium from the vacuole which paralleled Cu²⁺ accumulation, suggesting that it may represent some form of ion-exchange. An intracellular copper chelating agent of approximately 2 kDalton molecular mass was isolated from copper tolerant yeast. This chelator was not a metallothionein and bound relatively low molar equivalents of copper compared to those reported for metallothionein. Treatment of the biomass with hot alkali yielded two biosorbents, one soluble (which could be used as a heavy metal flocculent), and an insoluble biosorbent which could be formed into a granular product to be used in fixed-bed biosorption columns. The granular biosorbent could accumulate a wide range of heavy metal cations in a semispecific manner and could be stored in a dehydrated form indefinitely, and rehydrated when required. Bioaccumulation by live algae was investigated as an alternative to yeast based processes. Various strains of algae, of which Scenedesmus and Selenastrum were the most effective, were found to be capable of accumulating heavy metals such as Cu²⁺, Pb²⁺ and Cr³⁺.
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  • Date Issued: 1993

Blon

- Sali Sidibe (composition, lyrics, lead vocal), Boubacar Kane (djembe), Aminata Diabate, Fatim Sissoko (backing vocals), Rakesh Toure (keyboards), Mamadou Coulibaly (N'Bolon), Harouna Samake (N'goni), Zoumana Tereka (Violin), Samba Dioakite (Balafon), Sterns Africa label, Samassa Records

Chemical and spectroscopic studies of chromone derivatives

- Ramaite, Ipfani David Isaiah

  • Authors: Ramaite, Ipfani David Isaiah
  • Date: 1993 , 2012-11-16
  • Subjects: Heterocyclic compounds -- Derivatives -- Research , Benzopyrans -- Research , Coumarins -- Research
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4422 , http://hdl.handle.net/10962/d1006888 , Heterocyclic compounds -- Derivatives -- Research , Benzopyrans -- Research , Coumarins -- Research
  • Description: A number of biologically active chromones occur in plants (eg. Khellin) and research in this field has eventually led to the discovery of chromoglycic acid, which is widely used as a sodium salt in asthma therapy. Since biological activity may be related to acidity, a range of chromone-2-carboxylic acids have been prepared via Claisen acylation of substituted o- hydroxyacetophenones and their acid dissociation constants determined potentiometrically to explore substituent effects. From this study it has been found that introduction of certain groups does have a marked effect on acidity. A variety of acrylamide derivatives have been prepared via the dimethylamine-mediated ring opening of chromone-2-carboxamides which, in turn, were prepared from the chromone-2- carboxylic acids via the corresponding acid chlorides. Variable temperature NMR spectroscopy was employed to examine the effect of substituents on the rotational barriers and it has been found that for the acrylamides examined, ring substituents have little effect on the rotational barriers. A combination of low resolution, high resolution and meta-stable peak analysis has been used to study mass fragmentation patterns for a series of acrylamide derivatives. The proposed fragmentation pathways for selected peaks have been found to be common to all the spectra examined when differences in the atomic masses of substituents were taken into account.
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  • Date Issued: 1993

Chibhudhu

- Venancio Mbande and his Chopi timbila xylophone group, Tracey, Andrew T N

Co-occurrence of mated workers and a mated queen in a colony of Platythyrea arnoldi (Hymenoptera Formicidae).

- Villet, Martin H

  • Authors: Villet, Martin H
  • Date: 1993
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/447377 , vital:74619 , https://hdl.handle.net/10520/AJA00445096_510
  • Description: A colony of Platythyrea arnold; was found to contain a functional queen and laying workers, both virgin and mated. This form of social organization has never been reported in ants before.
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  • Date Issued: 1993

Coastal dune ecology and management in the Eastern Cape

- Avis, Anthony Mark

  • Authors: Avis, Anthony Mark
  • Date: 1993
  • Subjects: Sand dune ecology -- South Africa Shore protection -- South Africa Coastal zone management -- South Africa Sand dunes -- South Africa Sand dune plants -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4185 , http://hdl.handle.net/10962/d1003753
  • Description: The importance of understanding the ecological functioning of coastal dune systems is emphasized as being fundamental to the correct management of the dune landscape. Dune vegetation along the Eastern Cape coastline, from Cape St Francis in the west to Kei Mouth in the east was described in terms of the distribution and phytochorological affinities of the taxa. At a regional scale species distribution was strongly influenced by both the climate, particularly rainfall, and the phytochorological affinities of the taxa. Seven communities were defined using TWINSPAN, and the interrelationships between these communities in anyone area appeared to be linked to a successional gradient. Dune Slacks are thought to play a key role in this successional sequence, and a temporal study of this community led to a conceptual model of plant succession in these dunefields. Climate, particularly rainfall and wind, are major factors influencing plant succession. Wind-borne sand causes the slacks to migrate in an easterly direction under the influence of the predominantly westerly winds, although easterly winds, mainly in summer months may reverse these trends. Autogenic changes appeared to be important in this succession, and a comparative study of a good example of a primary succession at Mtunzini in Natal was undertaken to elucidate the main mechanism of change. Eight communities that were identified here were concluded to be distnbuted along a gradient of increasing age, with successional changes predictable, linear and directional. Species were grouped in distinct zones along the continuum and edaphic changes (decrease in soil pH, increase in organic matter and exchangeable bases) were related to the community based changes in species composition. The mechanism of change supported the facilitation model of plant succession which is a modification of the original Clementsian concept. Similar results were found in the Eastern Cape, but due to the harsh environment, multiple pathways of succession exist. Data from this study lent support to the model of plant succession developed earlier, and confinned that the dune slacks played an important role in this facilitation by acting as centres of diversity. The foredunes were found to have an indirect role in protecting these slacks from salt spray and sand movement. The central theme of the management studies was to investigate the ecological consequences of recreational pressure within the dune environment. Current levels of beach utilization at East London were lower than other beaches in South Africa, but a general trend of increasing utilization due to sociopolitical changes can be expected. The suitability of questionnaire surveys to assess aspects such as the adequacy of facilities, perceptual carrying capacity and the beach users opinion of natural vegetation and preference for particular beaches was demonstrated. The dune vegetation was found to be sensitive to human trampling, but at current levels, the ecological carrying capacity will not be exceeded since results of the aerial census counts and questionnaire survey revealed that few people entered sensitive zones such as the coastal forest. More detailed long term studies on the susceptibility of dune vegetation to both trampling and off-road vehicle impacts revealed a low resilience of dune plant communities to these effects. Although susceptibility differed between the three communities tested, generally the greatest amount of damage occurred after the first few passages, and vehicles caused a more significant decrease in height when compared to trampling. Recovery rates were slow and low levels of repeated damage were sufficient to retard or prevent the recovery of the plants. Stricter control of vehicle use on beaches is therefore required, and in high use zones the ecological carrying capacity should be increased by providing access tracks if possible, or if not possible, by restricting access. A historical account of the process of dune stabilization showed that although first initiated in 1845, indigenous species were only used in the past three decades. The use of alien species has resulted in problems such as a reduction in the ecological integrity and aesthetic appeal of coastal systems. The techniques applied in the stabilization of drift sands with indigenous vegetation have been successful, as revealed by a quantitative survey of 17 sites in the Eastern Cape. Sites were grouped by multivariate analysis on the basis of their species composition, and variability between sites was dependent on the types of species planted. Selection of suitable species is therefore important and is discussed with respect to their natural distribution along the coast. The long term objective of stabilization should be the creation of functional, diverse, aesthetic ecosystems, since the intrinsic and economic value of the dune landscape for tourism lies therein. However, detailed studies should be undertaken prior to implementing a manipulative process such as dune stabilization, since ecological processes may be disrupted. An understanding of such processes is therefore important if one wishes to effectively manage the dune landscape.
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  • Date Issued: 1993

Collaborative teacher participation in curriculum development : a case study in junior secondary general science (January 1991-November 1991)

- Naidoo, Premnandh

  • Authors: Naidoo, Premnandh
  • Date: 1993
  • Subjects: Science -- Study and teaching (Secondary) -- South Africa Curriculum planning -- South Africa Environmental education -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1451 , http://hdl.handle.net/10962/d1003332
  • Description: This research report describes an investigation that involved the collaborative participation of teachers in the redevelopment of parts of the Junior Secondary General Science syllabus. The redevelopment tried to implement environmental education as an innovation. There are two central assumptions that the investigation has made. The first assumption is that the the present Junior Secondary General Science syllabus lacks environmental relevance and therefore the pupils are inadequately prepared to deal with environmental problems. The introduction of a curriculum innovation like environmental education has the potential to bring greater environmental relevance to the syllabus. The second is that such an innovation can be more successfully implemented at schools if it involves the collaborative participation of teachers in the redevelopment of the syllabus. This assumption is made since evidence suggests that curriculum change can be a process of social reconstructive process when it takes place in situ and where teachers and pupils reshape the curriculum in the classroom as the teaching and learning progresses. An action research approach was selected since it is compatible with collaborative teacher, participation in curriculum development. The research design involved three parallel case studies: 1. Clermont Zone, 2. Durban Teachers Centre, 3. Edgewood College. The research confirmed that the Junior Secondary General Science syllabus is perceived by teachers to lack environmental relevance; that teachers, while initially resisting participation in the curriculum development process, were willing to participate if it revolved around their curriculum problems. Significant features of collaborative teacher participation in curriculum development seem to be the co-creation of context by the teachers, the need for institutional support, the production of curriculum materials and the need for networking and intercontextual dialogue. Teachers initially had limited curriculum development skills which needed to be developed. This research process has implications for practical actions 'to enable' the transformation of existing curriculums, and assisting the development of a more democratic and effective education system.
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  • Date Issued: 1993

Community-based development organisations in the Eastern Cape: towards survival and sustainability

- Davies, Bill, Madlavu, Mzukisi

  • Authors: Davies, Bill , Madlavu, Mzukisi
  • Date: 1993
  • Subjects: Community development corporations -- South Africa Community development -- Eastern Cape Community development -- Finance Community development -- Research -- South Africa Community development -- South Africa
  • Language: English
  • Type: Book , Text
  • Identifier: http://hdl.handle.net/10962/1708 , vital:20218 , ISBN 0868102520
  • Description: Community-Based Development Organisations (CBDOs) appear in many shapes and sizes, and a variety of (often confusing) terminology is used to describe them. The term CBDO is a generic one which refers to a broad class of organisations that are involved in one form or another of "community development" activities. Probably all CBDOs would describe themselves as non-governmental organisations (NGOs); and they could be service organisations, resource organisations (or both), or even welfare organisations. Some would see themselves as development agencies or as performing an advocacy/lobbying function on behalf of a more or less clearly defined constituency. Many CBDOs have a relatively narrow focus (for example, on some particular aspect of education or training - like literacy, teacher upgrading or technical skills)- whilst others pursue a broader range of activities associated with a spectrum of "community development" initiatives, projects or programmes. Much depends on the motivation for establishing a particular CBDO and its access to human and financial resources. They are part of the burgeoning Non- Profit Voluntary Sector in South Africa whose worth, in 1987, was estimated at a minimum of R2 billion - "and probably much more than that" , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
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  • Date Issued: 1993

Contemporary pollen spectra from the Natal Drakensberg and their relation to associated vegetation communities

- Hill, Trevor Raymond

  • Authors: Hill, Trevor Raymond
  • Date: 1993
  • Subjects: Pollen -- South Africa -- KwaZulu-Natal Palynology -- South Africa -- KwaZulu-Natal
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4199 , http://hdl.handle.net/10962/d1003768
  • Description: The research focuses on the contemporary pollen rain-vegetation relationship for vegetation communities within the Natal Drakensberg, a region which is recognized as having the potential for extensive palynological investigations. The objective was to investigate the fundamental assumption underlying palynology, viz: that the pollen rain of a particular region is indicative or representative of the existing vegetation of that region. If the modern pollen rain is indicative of and/or distinctive for a particular vegetation community then the principle of methodological uniformitarianism can be applied, which states that the present day patterns and relationships can provide a factual basis for the reconstruction of the past through the extrapolation of modern analogues backwards in time. A vegetation survey was conducted in thirteen communities identified as pertinent to the research and a two-year modern pollen rain sampling programme was carried out, using both surface soil and pollen trap samples as a means of recording and quantifying the pollen rain. Once the necessary sample preparation and pollen counts had been performed, descriptive and numerical/statistical methods were employed to determine and describe the existing pollen-vegetation relationship. Descriptive analysis of the data sets was carried out with the aid of spectra depicted as rotated bar graphs and representing the relative percentage frequencies of the collected/counted taxa. Annual and seasonal pollen influx values were calculated and presented. Analysis of variance was applied to test various hypotheses related to sampling strategy and pollen influx variation. Statistical methods employed were two-way indicator species analysis (a classification analysis technique), detrended correspondence analysis and principal components analysis (ordination techniques), canonical correlation analysis (for data set association) and multiple discriminant analysis (for determination of vegetation zonal indices). The latter technique allowed for the probability of modern analogues to be assessed which are necessary for accurate interpretation of fossil pollen assemblages if the assumption under investigation is correct. The findings of the study were that the modern pollen rain-vegetation assumption holds true. Recommendations are put forward regarding future contemporary pollen studies with regards to the number of soil and pollen trap samples required, the magnitude of the pollen count and the numerical/statistical techniques most appropriate to clearly interpret the results. The conclusions are that future fossil pollen spectra can be expected to provide a good indication of former regional vegetation patterns for the study region. The study has extended the limited understanding of the contemporary pollen rain-vegetation relationship in South Africa and enables the interpretation of fossil pollen spectra to be carried out with greater confidence. This in turn lends greater credibility to possible Quaternary environmental change models required to help understand present and possible future environmental change.
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  • Date Issued: 1993

CWIU Congress resolutions 1993 - Draft

- Chemical Workers Industrial Union (CWIU)

  • Authors: Chemical Workers Industrial Union (CWIU)
  • Date: 1993
  • Subjects: CWIU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/170159 , vital:41863
  • Description: The CWIU recognises the need to develop a long term organisational vision, develop and implement creative and effective strategies, prioritise campaigns/activities in order to be able to sustain these, adapt and change by a process of restructuring, deal effectively with political and economic issues. Development of a long term Vision Congress reaffirms our objective of a socialist future Our programmes must therefore reflect this vision. The trade union movement as a working class organisation has a major role in any socialist programme. The labour movement must remain independent. This independence must not be compromised. Overall strategy for trade union movement The current direction of Cosatu towards so called "Strategic Unionism" must be thoroughly discussed. A progamme of discussion on this must be implemented in the Union. We confirm our belief in the following principles and any strategy must be based on these: worker control, accountability of leadership a combination of negotiations,mass action and struggle as the means to achieve our goals/demands.
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  • Date Issued: 1993

Dambudzo Marechera. Cemetery of Mind Collected Poems 0f Dambudzo Marechera. Harare Baobab Books, 1992. Book Review

- Doherty, Christo

  • Authors: Doherty, Christo
  • Date: 1993
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/460528 , vital:75945 , https://journals.co.za/doi/epdf/10.10520/AJA00284459_555
  • Description: New Coin is one of South Africa's most established and influential poetry journals. It publishes poetry, and poetry-related reviews, commentary and interviews. New Coin places a particular emphasis on evolving forms and experimental use of the English language in poetry in the South African context. In this sense it has traced the most exciting trends and currents in contemporary poetry in South Africa for a decade of more. The journal is published twice a year in June and December by the Institute for the Study of English in Africa (ISEA), Rhodes University.
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  • Date Issued: 1993

Data reduction techniques for Very Long Baseline Interferometric spectropolarimetry

- Kemball, Athol James

  • Authors: Kemball, Athol James
  • Date: 1993
  • Subjects: Very long baseline interferometry Radio interferometers Data reduction -- Research
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5457 , http://hdl.handle.net/10962/d1005242
  • Description: This thesis reports the results of an investigation into techniques for the calibration and imaging of spectral line polarization observations in Very Long Baseline Interferometry (VLBI). A review is given of the instrumental and propagation effects which need to be removed in the course of calibrating such obervations, with particular reference to their polarization dependence. The removal of amplitude and phase errors and the determination of the instrumental feed response is described. The polarization imaging of such data is discussed with particular reference to the case of poorly sampled cross-polarization data. The software implementation of the algorithms within the Astronomical Image Processing System (AlPS) is discussed and the specific case of spectral line polarization reduction for data observed using the MK3 VLBI system is considered in detail. VLBI observations at two separate epochs of the 1612 MHz OH masers towards the source IRC+ 10420 are reduced as part of this work. Spectral line polarization maps of the source structure are presented, including a discussion of source morphology and variability. The source is sigmficantly circularly polarized at VLBI resolution, but does not display appreciable linear polarization. A proper motion study of the circumstellar envelope is presented, which supports an ellipsoidal kinematic model with anisotropic radial outflow. Kinematic modelling of the measured proper motions suggests a distance to the source of ~ 3 kpc. The cirumstellar magnetic field strength in the masing regions is determined as 1-3 mG, assuming Zeeman splitting as the polarization mechanism.
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  • Date Issued: 1993

Diaby

- Sali Sidibe (composition, lyrics, lead vocal), Boubacar Kane (djembe), Aminata Diabate, Fatim Sissoko (backing vocals), Rakesh Toure (keyboards), Mamadou Coulibaly (N'Bolon), Harouna Samake (N'goni), Zoumana Tereka (Violin), Samba Dioakite (Balafon), Sterns Africa label, Samassa Records

Digestible energy as a criterion for the development of diets for the African sharptooth catfish, Clarias gariepinus (Pisces: Clariidae)

- Rouhani, Q A

  • Authors: Rouhani, Q A
  • Date: 1993
  • Subjects: Clariidae , Catfishes -- Africa , Catfishes -- Nutrition -- Requirements -- Africa , Catfishes , Clarias
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5259 , http://hdl.handle.net/10962/d1005103
  • Description: Based on a number of attributes, the African sharptooth catfish, Clarias gariepinus is an ideal aquaculture species. Much work has been undertaken on developing the technology for the commercial culture of the species inclusive of determining the nutritional requirements for cost effective feed formulation. However, digestible energy (DE) values for specific feed ingredients were unknown. As DE values are not interchangeable between species, this study set out to determine the DE values for conventional and unconventional feed-ingredients for the formulation of an optimal feed. The ultimate goal in feed formulation is to produce a diet that supports the maximum production at the least cost. The indirect method was found to be most suitable in obtaining DE values for the catfish. Feed samples were marked by adding 2% chromic oxide as an inert indicator. The fish were then force-fed and faecal samples were obtained from the hindgut by stripping the fish 10 hours after feeding as this was found to be when the hind-gut was at its fullest and the feed maximally digested. A linear based computer programme was used to formulate experimental diets using the established DE values as an additional variable. The formulated feed was tested and compared to a commercial catfish diet and a standard reference diet (H-440). All of the newly formulated feeds were found to be cheaper to manufacture (by between 5 and 10%). Statistically (ANOVA), all of the experimental diets resulted in higher specific growth rates (SGR) than the standard reference diet. The commercial diet also resulted in a lower SGR than those experimental diets with similar protein levels.
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  • Date Issued: 1993

Ecological correlates of relative brain size in some South African rodents

- Bernard, Ric T F, Nurton, Jane P

  • Authors: Bernard, Ric T F , Nurton, Jane P
  • Date: 1993
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/447245 , vital:74599 , https://www.ajol.info/index.php/az/article/view/154234
  • Description: Relative brain size (size of the brain once body size effects have been removed) has been calculated for 16 species of rodent from South Africa and is shown to vary with six species having a positive RBS (that is a brain larger than expected) and 10 a negative RBS. Arboreal species such as Paraxerus cepapi and Graphiurus murinus and omnivores (G. murinus) have relatively larger brains than do the fossoriai root eaters such as Cryptomys hottentotus and terrestrial follivores (Otomys irroratus). It is suggested that the relatively large brains can be linked to the complex behavioural patterns necessary for locomotion in three dimensions and for utilization of a food resource such as insects that is randomly distributed in time and space. The three sciuromorph rodents (Xerus inauris, Paraxerus cepapi and Pedetes capensis) have very different life styles but all have a positive RBS and it is suggested that a relatively large brain may be a characteristic of the suborder.
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  • Date Issued: 1993

Ecology and natural history of the Masarid wasps of the world with an assessment of their role as pollinators in southern Africa (Hymenoptera : Vespoidea : Masaridae)

- Gess, Sarah Kathleen

  • Authors: Gess, Sarah Kathleen
  • Date: 1993
  • Subjects: Wasps -- Ecology Pollen wasps -- Ecology Vespidae -- Ecology Pollination by insects -- Africa, Southern
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5669 , http://hdl.handle.net/10962/d1005354
  • Description: The worldwide knowledge of the ecology and natural history of the masarid wasps, those wasps which bee-like provision their nest cells with pollen and nectar, is synthesized and discussed putting into context the investigations concerning nesting and flower visiting by southern African masarids conducted by the present author. Masarids are found mostly to favour warm to hot areas with relatively low rainfall and open scrubby vegetation. At the generic level the masarids of the Nearctic, Neotropical and Australian regions are distinct from each other and from those of the Palaearctic and Afrotropical regions combined. No species are shared between regions. Southern Africa is apparently the area of greatest species diversity. In this region, at least, there is a high incidence of narrow endemism. Masarids are associated with a relatively small range of plant families. Where sufficient records are available distinct major preferences are shown between zoogeographical regions. Relatedness of plant preferences between zoogeographical regions is apparent when relatedness of plant taxa is considered. Within a region there is marked overlap in masarid generic preferences for flower families. At the specific level there is marked oligolecty and narrow polylecty. The majority of nesting studies indicate that nest construction, egg laying and provisioning are performed by a single female per nest, however, nest sharing has been alledged for two species. No parasitic masarids have been recorded. Egg laying precedes provisioning. Mass provisioning is the rule. According to species, nests are sited in the ground, in non-friable soil or friable soil, in earthen vertical banks, on stones or on plants. Seven nest types are defined. Three bonding agents, water, nectar and self-generated silk are used. Masarids are evaluated as potential pollinators of their forage plants in southern Africa. The "masarid pollination syndrome", though less broad is shown to fall within that designated melittophily. The case studies considered make it clear that, whereas the masarids visiting some flower groups are members of a guild of potential pollinators, the masarids visiting others are probably their most important pollinators. Increasing land utilization is shown to threaten the existence of narrowly endmic masarid species.
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  • Date Issued: 1993

English in South Africa : effective communication and the policy debate : inaugural lecture delivered at Rhodes University

- Wright, Laurence

Epidemiological and aetiological aspects of diarrhoeal disease in the Eastern Cape

- Baxter, Esther

  • Authors: Baxter, Esther
  • Date: 1993
  • Subjects: Diarrhea -- South Africa , Intestines -- Diseases , Pathogenic microorganisms -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4045 , http://hdl.handle.net/10962/d1004106 , Diarrhea -- South Africa , Intestines -- Diseases , Pathogenic microorganisms -- South Africa
  • Description: Diarrhoeal disease is a major cause of mortality in children in developing countries. It also remains a serious problem among all age groups throughout the world. Whereas studies to determine the epidemiological and aetiological factors of diarrhoeal disease have been reported for other parts of South Africa and the world, as yet no information is available for the Eastern Cape. Therefore this study was undertaken to determine the factors for this area. Enteropathogens were compared for the different ages in the various population groups and, where possible, seasonal and geographical differences were emphasised. A total of 7 278 faecal samples were examined by six laboratories in the Eastern Cape during the period November 1988 to October 1990. Data was recorded noting the age, sex and population group of the patients. The towns selected were Port Elizabeth, Uitenhage, Cradock, Grahamstown and their surrounding areas. The isolation rates for the pathogens studied in the various population groups were compared to those reported in similar studies in other countries. The seasonal incidences of the various selected pathogens were compared with those reported from elsewhere in South Africa. It was thought that the higher temperature of summer may influence the finding in the White population group, while rainfall would play a greater role for the Coloured and Black populations. The geographical distribution of the pathogens emphasised the difference in living conditions between the different population groups. For example a generally higher infestation rate of Helminths occurred in rural areas and in the groups living under poorer conditions. The low isolation rates for certain bacteria and the large percentage of samples from which no pathogens were isolated indicate the need for further research. However, the finding should be valuable for determining Public Health priorities and in the management of outbreaks of diarrhoeal disease.
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  • Date Issued: 1993

Evaluation of environmental education courses in Bophuthatswana colleges of education

- Leketi, Makgau Peter

  • Authors: Leketi, Makgau Peter
  • Date: 1993
  • Subjects: Environmental education -- South Africa -- Bophuthatswana Environmental education -- Study and teaching -- South Africa -- Bophuthatswana Environmental education -- Curricula -- South Africa -- Bophuthatswana
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1525 , http://hdl.handle.net/10962/d1003407
  • Description: This study evaluates Environmental Education courses in Bophuthatswana Colleges of Education. The semi-structured interviews with final year students, lecturers, rectors of colleges offering the courses, external examiners and the course co-ordinator at the Institute of Education at the University of Bophuthatswana (Unibo) are made. Written documents relating to Environmental Education courses, such as students' examination answer books, moderators' reports and minutes of meetings, are also used to evaluate the courses. Specifically, the aim of this study is to identify the strengths and the weaknesses of Environmental Education courses in Bophuthatswana Colleges of Education and this would present a contribution in the research field and also be useful in the further refinement of the courses. Strengths and weaknesses identified in this research are related to knowledge of Environmental Education and environmental issues, the syllabuses of the Environmental Education courses, the operation of the courses, the examining of the courses and the ethos and support of the colleges and the local university's Institute of Education. New insights are gained inter alia into the operation of Environmental Education courses in the Teacher Education programme in Bophuthatswana. An important contribution of the study is the application of the phenomenological paradigm, since it allows understanding of subjective experience as far as the operation of Environmental Education is concerned.
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  • Date Issued: 1993
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