List of Titles

Ecology and degree of specialization of South African milkweeds with diverse pollination systems

Authors: Coombs, Gareth
Date: 2010
Subjects: Milkweeds -- South Africa Milkweeds -- South Africa -- Ecology Milkweeds -- South Africa -- Pollination Allee effect Self-pollination Pollination by insects
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:4189 , http://hdl.handle.net/10962/d1003758
Description: Like orchids, the complexity of flowers found in asclepiads (Asclepiadoideae, Apocynaceae) and the fact that pollen is presented as pollinaria, offers excellent opportunities to study various aspects of plant-pollinator interactions. In this thesis I investigated two broad themes: ecological aspects of the pollination biology of hymenopteran and fly-pollinated asclepiads as well as the degree of specialization to certain pollinators in these species. Colonizing plants often reproduce through self-pollination, or have highly generalized pollination systems, or both. These characteristics facilitate establishment in small founding populations and generates the prediction that reproductive success should be independent of population size in these species. Chapter one examines the pollination biology of Gomphocarpus physocarpus, an indigenous, weedy species and investigates the relationship between reproductive success and population size. In this species, there is no evidence of an Allee effect and reproductive success is not correlated with population size. In addition G. physocarpus is not capable of self-pollination, suggesting it is completely reliant on pollinators for seed set. The lack of a relationship between pollination success and population size is therefore likely explained by the generalized wasp pollination system of this species. Several milkweeds are invasive outside of their native ranges. Invasive species either need to co-opt native pollinators in order to reproduce or reduce their reliance on pollinators through having the ability to self-pollinate. Co-opting native pollinators is expected to be easier in species that have generalized pollination systems, alternatively species with specialized flower morphologies need to rely on similar functional groups of pollinators to be present within the invaded range. Chapter two investigates the pollination biology and pollination success of the invasive milkweed, Araujia sericifera, and finds that in South Africa, this species is visited mainly by native honeybees and nocturnal moths. Moths however contribute little to pollen removal, and deposition. Based on the apparent morphological mismatch between the flower of A. sericifera and native honeybees, I propose that the native pollinators of this species are likely to be larger Hymenoptera (e.g. Bumblebees). Data from a breeding system study, indicated that this species is not capable of automatic self-pollination, but could set fruit from geitonogamous self-pollinations pointing to the importance of native pollinators for successful reproduction. The pollinaria of milkweeds can accumulate on pollinators to form pollen masses large enough to physically interfere with the foraging behaviour of pollinating insects. In chapter three I describe the pollination biology of Cynanchum ellipticum and find that this species is mainly pollinated by honeybees although this species is visited by several other members of Hymenoptera, Lepidoptera and Diptera. Due to the structure of the pollinaria, these chain together relatively efficiently and frequently form large pollinarium loads on the mouthparts of honeybees. However there is little evidence that these pollinarium loads influence the foraging times of pollinators and only a few individual honeybees exhibited longer foraging times and most honeybees were unaffected by the presence of large pollinarium loads. Within the genus Cynanchum there is large variation in the gynostegium structure that may influence the pattern of pollinarium loading on pollinators as well as pollen reception as shown in chapter three. In Chapter four, the pollination biology of Cynanchum obtusifolium is examined, and like that of C. ellipticum, this species is visited by a wide diversity of pollinators but honeybees appear to be the primary pollinators. More importantly this species is shown to be andromonoecious and produces two morphologically different flower types, that may be distinguished based on differences in the gynostegium structure. These two types of flower could mainly be distinguished by the length of the anther wings. I found that flowers with short anther wings function as male flowers by only exporting- and rarely receiving pollinia. Flowers with longer anther wings function as hermaphrodite flowers and can both export and receive pollinia. The ratio of male to hermaphrodite flowers varied at different times during the flowering season, but preliminary data suggested that this was not related to levels of pollination success. The genera Stapelia and Ceropegia are well known for their intricate floral adaptations that mimic the brood and feeding substrates of pollinating flies. Despite several studies that have documented the various adaptations to fly pollination in different species, there is a lack of natural history studies documenting different flower visitors, pollen loads and long term levels of pollination success in these species. In Chapter six I document the pollination biology of Ceropegia ampliata by documenting different pollinators and quantifying average levels of pollination success and the nectar reward. I also experimentally manipulated the trapping hairs of this species to determine whether trapping hairs influence average levels of pollen export and receipt. I show that Ceropegia ampliata is pollinated by a generalist guild of flies (mainly Tachinidae, Sarcophagidae, Muscidae and Lauxaniidae) and produces minute quantities of relatively dilute nectar as a reward. Pollination success was generally low in this species and increases periodically suggesting that the abundance of pollinators is patchy. I found that flowers with trapping hairs that had already wilted had higher levels of pollinarium removal than flowers with erect hairs, however experimentally removing the hairs had no significant effect on pollen export and receipt. In Chapter seven, I document the pollinators, pollen loads and long term levels of pollination success in Stapelia hirsuta var. bayllissi, a rare sapromyiophilous stapeliad. I find that, in contrast to C. ampliata, this species was specialized to pollination by small flies of the family Anthomyiidae. Similar to the results from Chapter seven, I find that long term levels of pollination success were typically low but could increase periodically, although such increases were generally unpredictable. There are currently very few records documenting pollinator interactions in the Periplocoideae. Many species within this subfamily exhibit open-access flowers suggestive of pollination by short-tongued insects. I investigated the pollination biology of Chlorocyathus lobulata, a rare species with a highly localized distribution. I aimed to determine the pollinators, average levels of pollination success and demography of this species in order to determine whether this rare species is suffering from the collapse of a highly specialized pollinator mutualism. I also quantified the high incidence of flower herbivory caused by larvae of the moth, Bocchoris onychinalis. I find that C. lobulata has a highly generalized fly pollination system and average levels of pollination success suggested that a large proportion of flowers had pollen removed and deposited suggesting that this species is not experiencing pollination failure. The large numbers of juveniles present also indicated that recruitment is taking place.
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Date Issued: 2010

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)

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

Ecology of key cerithioidean gastropods in the mangroves of the iSimangaliso Wetland Park, KwaZulu-Natal South Africa

Authors: Raw, Jacqueline Leoni
Date: 2017
Subjects: Gastropoda -- South Africa -- KwaZulu-Natal Mangrove ecology -- South Africa -- KwaZulu-Natal
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10948/11942 , vital:27009
Description: Gastropods are one of the most diverse species groups in mangrove habitats, however, many of their specific roles in relation to ecological patterns and processes are currently largely unknown. The overall aim of this research project was to provide basic ecological information for key gastropod species from subtropical mangroves within a protected area. South African mangroves cover relatively small areas and are restricted to estuaries, these habitats therefore present unique opportunities and challenges to the species that occur in them. Three gastropod species, Terebralia palustris, Cerithidea decollata, and Melanoides tuberculata, all occur at their natural southernmost range limit within South Africa and were selected based on their prominence and occurrence in mangrove habitats of the iSimangaliso Wetland Park, a UNESCO World Heritage Site. Trophic linkages and resource partitioning, resource utilization rates, and ecological resilience were investigated respectively using: 1) a stable isotope (δ15N and δ13C) approach; 2) an experimental approach to quantify feeding dynamics (ingestion rate, consumption/digestion efficiency and grazing impact); and 3) a mixed-effects modelling approach to relate population responses to environmental variables. The diet of T. palustris was seasonally variable and a number of sources were incorporated by different sized snails, but their grazing impact on microphytobenthos was not significant. The results also indicated an ontogenetic shift in the dietary niche for T. palustris through robust partitioning of resources between different size classes. The diets of C. decollata and M. tuberculata were dominated by different primary resources as a function of where they occurred in the mangroves. Melanoides tuberculata consumed a wide variety of primary resources, a typical trait of an opportunistic generalist species. The ingestion rate of M. tuberculata was not dependent on the availability of microphytobenthos, and was highest when conditions were oligotrophic. The resilience of C. decollata was related to the tree-climbing behaviour of this species and its occurrence was best explained by sediment conductivity. These responses were considered in conjunction to what has previously been reported on the resilience of the mangrove trees. The results of this research project have provided new basic ecological information for all three gastropod species in this data-deficient subtropical region. This information can potentially be used in comparative studies for these species in other regions or in broader scale ecological studies. Terebralia palustris has recently experienced a range contraction along the South African coastline. This research project has shown that the diet of this species is highly variable and that food limitation and competition for resources should be considered as potential drivers of the local decline. Cerithidea decollata has in contrast expanded its distributional range in this region. This research project has shown that this species has a generalist diet and exhibits traits in relation to tolerance that are expected to have facilitated its expansion into temperate saltmarsh habitats that occur in dynamic estuaries. Melanoides tuberculata is a globally invasive species, and as South African populations are within its native range, ecological information from this region is valuable as it can be used to investigate the potential ecological effects following introduction into new habitats beyond the native range. Biological drivers have a significant impact on mangrove ecosystem functioning, particularly in relation to recycling and the retention of organic carbon generated through primary productivity. Understanding the ecological linkages that maintain ecological functioning and stability is therefore an important step towards conserving and sustainably managing threatened ecosystems such as mangrove forests.
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Date Issued: 2017

Ecosystem services in a biosphere reserve context: identification, mapping and valuation

Authors: Ntshane, Basane Claire
Date: 2017
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/4536 , vital:20686
Description: Despite their contribution to human well-being, ecosystem services (ES) are being destroyed by anthropogenic activities, taken for granted and often compromised during land use decision making. The question that often arises is, what value do ES have compared to other undertakings that are economically robust, such as mining? The vision of the Millenium Ecosystem Assessment (MA) was a world in which natural assets (including ES) are appreciated and integrated into decision-making. The biodiversity strategy of the Convention on Biological Diversity (CBD) also concerns the integration of natural assets into decision making. Responding to challenges facing ES and their mainstreaming into decision-making has been constrained by lack of data and requires new tools and approaches. Integrating natural assets into decision-making is very important for South Africa (SA), where ES have been a crucial part of human systems for decades, and also because of the country’s commitment to the implementation of the CBD's biodiversity strategy. With the aim of incorporating ES into decision-making in an integrated way, this study was conducted in two biosphere reserves (BRs), Vhembe and Waterberg, in Limpopo Province, SA. The aims of the study were the identification, mapping and valuation of ES following an integrated approach. In order to achieve these aims, the study attempted to address four key objectives: (1) to assess and evaluate the status of mapping and valuation of ES in SA, (2) to identify and quantify ES and their indicators, (3) to investigate and analyse the impact of land use/cover (LU/LC) change to ES and (4) to conduct valuation of selected ES. Two separate literature reviews were undertaken to assess and evaluate the status of mapping and valuation of ES in SA, thus addressing study objective 1. Both reviews detected a significant research gap with regard to mapping and valuation of supporting services in SA. To identify ES and indicators provided by the two BRs and to assess the impact of LU/LC change and its effect on ES, a participatory scenario planning process was conducted under three different scenarios, namely ecological development, social development and economic development. It became clear that LU issues were diverse in nature and affected ES in a number of ways and that there were always trade-offs in the choice of LU. For example, yields of ES were best in the ecological development scenario and were affected negatively, together with agricultural commodity production, in the social development and economic development scenarios. A mapping exercise was undertaken to illustrate the spatial distribution of ES supply and demand, involving five ES and 15 indicators using existing datasets and the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) mapping tool, again addressing objective 2 of the study. Carbon storage and habitat quality were assessed, modelled and quantified and their values provided in biophysical terms using InVEST modelling tools, thus addressing objective 4 of the study. High quantities of carbon storage and high habitat quality were recorded in natural areas and low quantities were recorded in managed systems (cultivated, urban and plantation areas). InVEST was again applied to conduct an economic valuation of two provisioning ES, timber and firewood, by determining their net present values, attempting to address objective 4 of the study. Results revealed that, at 12% discount rate, the net present value (NPV) for timber production accounted for R23 317/ha in VBR and R57 304/ha in WBR. However, at lower discount rates (4 and 7%), the NPVs for timber were negative in VBR and positive in WBR. With regard to firewood production, the NPVs were negative against all three discount rates in both study areas. I conclude by proposing a four-step integrated approach that can aid the successful incorporation of ES into decision-making: (1) maintain a balance between the social, economic and ecological aspects when making decisions on ES, (2) strive for an evidence- based approach to decision-making (use quantities and values), (3) apply integrated approaches (methods and techniques) to quantification and valuation, and (4) communicate all steps along the way. The results of this study will serve as a baseline for integration of ES into decision-making in SA.
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Date Issued: 2017

Effect of increasing fossil shell flour levels on digestive and metabolic utilization, health, body weight change and wool production, and quality in Dohne-Merino wethers

Authors: Ikusika, Olusegun Oyebade
Date: 2020
Subjects: Merino sheep Sheep -- Quality
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10353/18465 , vital:42542
Description: The study's broad objective was to assess growth performance, blood and parasitic profiles, wool parameters, methane emission, and nutritional status of Dohne-Merino wethers fed diets supplemented with varying levels of fossil shell flour. Twenty-four Dohne-Merino wethers, averagely weighing 20.0±1.50 kg, were divided into four groups and used in this study. The effects of varying inclusion levels of fossil shell flour (FSF) (0, 2, 4, and 6 %) on feed intake, water intake, nutrient digestibility, N-retention, hematobiochemical and parasitic profiles, body condition scores, feed preference, wool parameters and methane output were determined. The influence of FSF's varying inclusion levels on fermentation parameters, in vitro true digestibility, and relative feed values were also determined. Wethers fed with 4% FSF inclusion level diet showed the highest (P<0.05) values for dry matter intake, average daily weight gain, N retention, (Nitrogen retention) and apparent digestibility of crude protein (CP), Ether Extract (EE) and Ash 6 % (P < 0.05). The urinary N and fecal N were lowest in wethers fed 4% FSF inclusion level and highest in those fed on diets without FSF (P < 0.05). Water intake was highest in wethers fed 0% FSF diet, followed by those fed on 4% and lowest in 6% FSF (P< 0.05). There was a significant increase in white blood cell counts in wethers fed on a diet with 4% and 6% FSF inclusion levels from day 10 to 100 compared to wethers fed on a diet with 0% and 2% FSF (P <0.05). Red blood cell counts also increased significantly in wethers fed on a diet containing 4% FSF, but a slight increase in wethers with 6 % FSF diet, throughout the experimental period (P < 0.05). Blood urea was highest in wethers fed 0% FSF inclusion level and lowest in 6% at day 30 to day 100. Wethers on 4% FSF diet showed an increase in blood urea from day 30 to day 100 (P < 0.05) while wethers on 0% and 2% remained unchanged (P<0.05) during this period and not different (P > 0.05) from wethers on 4% FSF as well. The total protein concentration, albumin, total bilirubin, Na, K, glucose, cholesterol, and liver enzymes were normal for wethers. However, serum creatinine level was lower in wethers fed on 4% FSF than those on 0% FSF (P < 0.01). Haemonchus and Coccidian fecal egg counts were low in wethers fed diets with 2%, 4%, and 6 % FSF (P < 0.01) compared 11 with wethers fed with 0% FSF inclusion level during the same period. The body condition score of wethers fed on diets with 2%, 4%, and 6% FSF inclusion levels were higher than those on 0% (P < 0.05). Wool yield, staple length, the coefficient variation of the fibre diameter, and fibre of wethers fed on diets with FSF were higher than those without FSF (P < 0.05). The fibre diameter of the wethers fed on FSF supplemented diets was the same as those on 0 % FSF (P > 0.05). The wethers spent more time on FSF supplemented diets and consumed more feed compared to that without FSF supplemented (P < 0.05). The levels of FSF inclusion in the diet affected the enteric methane output (ppm-m), where 4 % FSF had the highest enteric methane output while wethers on 2 % FSF had the lowest methane output (P < 0.05). Resting wethers produced more methane (g/day) than those feeding or standing (P < 0.05). Increasing levels of FSF did not affect ruminal temperature and pH. Ammonia-N increased with increasing FSF except in wethers fed on a diet with 4% FSF (P < 0.01). The total molar concentrations of the wethers' volatile fatty acids decreased with increasing FSF levels (P > 0.05). The acetic propionic ratio of the wethers also decreased except at a 4% inclusion level. The in vitro true digestibility dry matter (IVTDDM), in vitro true digestibility neutral detergent fibre (IVTDNDF), and in vitro true digestibility acid detergent fibre (IVTDADF) of the wethers decreased up to 4% FSF inclusion but tended to increase at 6% inclusion. This study's result as one of the pioneer studies in Dohne-Marino wethers showed that FSF treatment has the potential to improve the nutritional status of the animal and the animal performance and wool quality. Health-wise, FSF decrease nematode population and boost animal immunity as seen in RBC and WBC counts. It also can play a major role in protecting the environment, as seen in its reduction in feacal and urinary nitrogen, which is heavily involved in environmental pollution. Result also confirmed that the best period to target for methane mitigation in ruminants is the resting period. In conclusion, the inclusion of FSF in the diet of Dohne-Merino wethers has the potential to improve the overall performance, with a 4% FSF inclusion level having optimal productivity. However, future research is required to investigate FSF's effect on meat quality, rumen microbial community, in-vivo digestibility, and milk production.
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Date Issued: 2020

Effects of lethal management on black-backed jackal population structure and source-sink dynamics

Authors: Minnie, Liaan
Date: 2016
Subjects: Black-backed jackal Carnivorous animals
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10948/12658 , vital:27104
Description: Lethal carnivore management, aimed at reducing carnivore impacts, threatens the persistence of carnivores globally. The effects of killing carnivores will depend on their life histories and social structures. Smaller canids, like black-backed jackals (Canis mesomelas), are highly adaptable and display variable population-level responses to mortality sources, which may contribute to their success in fragmented landscapes. Jackals, the dominant predator of livestock in South Africa, are widely hunted to reduce this predation. This hunting is heterogeneous across the landscape, focussed on livestock and game farms, with nature reserves acting as refuges. The aim of this research was to investigate the ecology and population dynamics of jackals in response to heterogeneous anthropogenic mortality. I hypothesized that the spatial variation in hunting results in the formation of a source-sink population structure, which contributes to the persistence of jackals. I addressed this hypothesis by evaluating two criteria, essential for the formation of a source-sink system in larger mammals. Firstly, I confirm that hunting pressures result in the formation of distinct subpopulations with asymmetrical dispersal (i.e. compensatory immigration) from unhunted reserves to neighbouring hunted farms. Secondly, I show that jackal subpopulation display asynchronous demographics, with farm populations displaying a relatively younger age structure and an associated increase in reproductive output (i.e. compensatory reproduction). This confirms the formation of a hunting-induced source-sink system. additionally, I show that jackals have a catholic diet, which confers a level of adaptability to direct (anthropogenic mortality, prey provisioning) and indirect (alteration in prey base) habitat modifications. This dietary flexibility allows jackals to obtain the appropriate resources to achieve reproductive condition. The relatively better body condition of younger jackals in sink habitats allows for compensatory reproduction which contributes to the success of jackals on hunted farms. Based on my findings, I hypothesize that the compensatory life history responses of jackals to anthropogenic mortality may be ascribed to two interconnected mechanism. Dispersal is presumably driven by density-dependent interference competition, as dominant territorial pairs outcompete subordinates in high-density reserve areas, forcing them to disperse onto low-density farms (i.e. ideal despotic model). Additionally, farms likely represent attractive habitats, owing to a reduction in conspecifics and a concomitant increase in resource availability (including anthropogenic resource provisioning). Therefore, dispersing subordinates presumably select for farms which are perceived as good quality habitats, as the high risks of anthropogenic mortality cannot be perceived by dispersing individuals. This results in the formation of an attractive sink or ecological trap. These compensatory processes will continue to counter population management actions as long as recruitment from unmanaged areas persists. This hypothesis provides a conceptual framework for future research directions in understanding jackal persistence and management (i.e. specifically focussing on controlling dispersal) of jackal populations.
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Date Issued: 2016

Effects of sustained Russian wheat aphid (Diuraphis noxia Mordvilko) feeding on leaf blades of wheat (Triticum aestivum L. cv Adamtas)

Authors: Matsiliza, Babalwa
Date: 2003
Subjects: Russian wheat aphid Wheat -- Diseases and pests
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:4213 , http://hdl.handle.net/10962/d1003782
Description: Penetration of sink as well as source leaves of wheat plants by the Russian wheat aphid, Diuraphis noxia (Mordvilko) was investigated using light, fluorescence and transmission electron techniques, to determine the feeding strategies adopted by the aphid in penetrating and successfully feeding from the phloem, and to assess the structural effects of the probing and feeding behaviour of D. noxia on the feeding sites. Examination of aphid-infested sink, as well as source leaf tissue, showed that D.noxia probed in cells of the vascular bundle more frequently than mesophyll cells. Within the vascular bundle, thin-walled sieve tubes were visited (probed) more than the other cells. In sink leaf material, 68 of 82 (83%) stylets and stylet tracks encountered during the examination of 1000 serial sections (from 5 different plants) terminated in thin-walled sieve tubes and only 14 (17%) in thick-walled sieve tubes. Thin-walled sieve tubes were visited more significantly than thick-walled sieve tubes. However, examination of the aphid.,.infested sink leaf on a per centimetre basis, from the tip of the leaf, revealed that thick-walled sieve tubes in the area closest to the tip (0-2cm from the tip) were as attractive to the aphid as were thin-walled sieve tubes, with no significant difference in the number of times thick- and thin-walled sieve tubes were probed in this area. Some 2-4cm from the tip however, thinwalled sieve tubes were significantly more probed and therefore more attractive than thick-walled sieve tubes. Examination of 2000 serial sections using aphid-infested source leaf tissue, showed that the thin-walled sieve tubes were significantly more probed than thickwalled sieve tubes, along the whole leaf, expressed as a total of all leaves, as well as on a per centimetre basis along the length of the leaf, with 212 (95%) of 222 terminations within the thin-walled sieve tubes and only 10 (5%) in thick-walledsieve tubes. The aphid probed the small vascular bundles (loading bundles) many more times than intermediate or large transport vascular bundles, in sink as well as source leaf. Of a total of 82 stylets and stylet tracks encountered in sink leaf tissue, 31 terminated in small vascular bundles ang the remaining 28 and 16 were located within large and intermediate vascular bundles respectively. In source leaf tissue 121 of 222 stylets and stylet tracks encountered were associated with small vascular bundles and only 58 tracks and 43 tracks with intermediate and large vascular bundles, respectively. The effect of sustained RWA feeding on the transport capacity was examined after the application of 5,6 carboxyfluoresceine diacetate (5,6-CFDA) in control (sink and source leaf tissue) and aphid-infested (source) wheat leaves, using fluorescence microscopy. After 3h acropetal longitudinal transport of 5,6-CF had occurred in sink leaves in longitudinal veins, as well as a lateral transfer via cross veins and subsequent unloading into mesophyll cells close to the tip of the leaf was observed. In control leaf tissue, the fluorescence front was detected up to about 5cm from the point of application and was only associated with the phloem and not unloaded. In contrast, aphid-infested leaf tissue showed very little 5,6-CF transport, being limited to 2cm or less from the point of application. Structural damage to the phloem in general and to the sieve tubes in particular within of control and infested wheat leaves was investigated using transmission electron microscopy (TEM). In addition, leaf strips were mounted in aniline blue to visualise callose deposition using the fluorescence microscopy. At the TEM level. infested leaf tissue showed various abnormalities, which included destruction of cell contents, membrane damage and subsequent loss of cell contents. TEM studies suggest severe osmotic shock resulted from the aphid's probing. Examination of leaf tissue using fluorescence microscopy showed that there was very little characteristic aniline blue-stained callose visible in control leaf tissue, other than the thin diffuse patches along the sieve plates and punctate spots associated with pore plasmodesmatal areas and plasmodesmatal aggregates. In contrast, the aphid-infested leaf tissue was heavily callosed, with callose deposited not only within the phloem tissue but also in neighbouring vascular parE:}nchyma cells as well. The data collectively suggest that D. noxia feeds preferentially within thin-walled sieve tubes, within the small longitudinal vascular bundles in sink , as well source leaf tissue. Based upon the data presented here the thin-walled sieve tubes in the wheat leaf appear to be more attractive to the aphid and that they are probably more functional in terms of transport system and unlo?lding in sink leaves. Aniline blue stained leaf material that had previously hosted large aphid colonies showed evidence of extensive callose deposits 24 to 36h after the aphids were removed, suggesting that the aphids caused severe mechanical damage to the vascular tissue and mesohyll cells as well. Damage (transient or more permanent) and the subsequent deposition of wound callose, disrupted phloem transport and hence the export of photoassimilate from the leaves.
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Date Issued: 2003

Effects of temperature on the development, behaviour and geography of blowflies in a forensic context

Authors: Richards, Cameron Spencer
Date: 2008
Subjects: Blowflies Blowflies -- South Africa Diptera -- South Africa Insects -- Development Insects -- Behavior Forensic entomology
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:5683 , http://hdl.handle.net/10962/d1005369
Description: The development of immature insects is commonly employed in forensic investigations to estimate time of death, or postmortem interval (PMI), of a corpse on which they are feeding. The bulk of this thesis focuses on factors influencing the accuracy of developmental data, and exploring how and why developmental data differ between studies involving the same species, and between different species. Because carrion feeding insects are ectotherms, temperature may be expected to significantly influence their behaviour, development and distribution, and the remainder of the thesis therefore focuses on the thermal biology and geographical distribution of seven forensically important blowflies. The species include Chrysomya albiceps, C. putoria, C. chloropyga, C. megacephala, C. marginalis, C. inclinata and Calliphora croceipalpis. A robust experimental design for estimating developmental models is outlined and tested. It is recommended that forensic entomologists should involve at least six constant temperatures, starting at about 7°C above the relevant developmental zero (D0) and going to about 10°C above the upper critical temperature, and a temporal sampling interval with a relative precision of about 10%. Using this design, focused experiments consistently provided the most reliable developmental data, while data pooled from different studies yielded inconsistent results. Similarly, developmental data from closely related species differed significantly, and surprisingly so did developmental data from different populations of the same species. Possible explanations for the latter lay in the different methods of data collection but only temporal sampling resolution had a direct influence on the accuracy of developmental data. Consequently, disparities in such data were primarily ascribed to genetic differences and phenotypic plasticity. Comparisons between numerous thermal thresholds of larvae, pupae and adults support this conclusion and suggest a phylogenetic component to the thermal biology of blowflies. Further comparisons were made between these temperature thresholds and the distributions of blowfly species present on two rhinoceros carcasses. These comparisons suggest that blowfly larvae with high upper lethal temperature thresholds dominate in interspecific competition in favorable thermal environments by raising maggot mass temperature above the thresholds of other carrion-feeding blowflies, through maggot-generated heat. Bioclimatic modeling using maximum entropy analysis provided a successful means of predicting whether a species is likely to occur in an area, and whether it would therefore be expected in a local carcass community. It also showed that temperature was less important than moisture in shaping the geographical distribution of African carrion blowflies. Based on these results, several recommendations are made for the practice of forensic entomology.
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Date Issued: 2008

Elasticity of the South African economy towards portfolio investments in BRICS countries

Authors: Taonezvi, Lovemore
Date: 2019
Subjects: Economic development -- South Africa
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10948/44537 , vital:38141
Description: The emerging economies of Brazil, Russia, India, and China (BRIC) have been experiencing high growth rates since the turn of the millennium, whereas economic growth has been elusive in South Africa. As the newest member of BRICS, South Africa is expected to economically benefit through, amongst others, increases in capital flows, foreign investments by local firms, and increases in trade. Such benefits are anticipated to propel the country’s economic growth, thereby helping it to tackle its chronic problems of high unemployment, poverty, and economic inequality. The inclusion of South Africa in BRICS has, however, been viewed by critics as erroneous, since the country has, inter alia, poor economic growth; a small economy and population; and political instability. While foreign portfolio investment (FPI) inflows to South Africa have surged in recent years, economic growth has remained lacklustre. These flows have also faced sudden reversals, especially during the financial crisis of 2007-2009. With the potential to leverage its growth from intra-BRICS FPI inflows, it becomes of paramount significance for policymakers to have knowledge of the South African economy’s responsiveness to such inflows. With a theoretical framework based on the endogenous growth model, an augmented Cobb-Douglas production function was extended in this thesis in order to study the relationship between BRICS growth and intra-BRICS FPI in a dynamic panel data generalised method of moments (GMM) context. Similarly, the South African economy’s elasticity towards intraBRICS FPI was estimated. Vector autoregressive (VAR) analysis was used to evaluate the responsiveness of South Africa’s economy to an innovative shock to intra-BRICS FPI. Annual and quarterly data for the period 2000-2016 were used in panel data and VAR analysis, respectively. It was found that intra-BRICS FPI flows have a positive and statistically significant relationship with BRICS growth, while the elasticity of the South African economy to these flows is estimated at 0.007. Additionally, the efficiency and accessibility dimensions of financial market development do not assist FPI in promoting growth in BRICS, while financial market depth does. South Africa’s BRICS membership has a positive effect on its own growth, while for other BRICS nations, this membership is negative and insignificant. Credit rating downgrades have a negative and insignificant impact on economic growth, while the negative impact for inflation, government expenditure, and total labour employment is significant. Conversely, gross capital formation and trade openness have a positive and significant relationship with BRICS growth. The study also determined that a unit shock on intra-BRICS FPI resulted in negative fluctuations of South Africa’s economy within the first eight quarters before being positive and mostly constant thereafter. By supplementing domestic savings and facilitating the international integration of domestic financial markets, FPI promotes growth in BRICS. The short-term, ease of reversibility, and speculative nature of FPI are amongst some of the reasons for its destabilising effect on South Africa’s economy. Furthermore, inflation is a key determinant of FPI inflows to South Africa. Additional BRIC cooperation in FPI and trade; increased investments in domestic capital; reductions of inflation and corruption; investments in education and skills development; and stock market reforms are some of the recommendations for BRIC, and South Africa in particular. South Africa can consider prudential use of a mix of capital account controls, as well as fiscal and monetary policies to cushion its economy from FPI shocks in the short- to medium-term.
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Date Issued: 2019

Elements of dream interpretation: laying the foundation of a basic model for clinical practice

Authors: Schön, Joan
Date: 2001
Subjects: Dream interpretation Dreams
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:3050 , http://hdl.handle.net/10962/d1002559
Description: The study addresses certain paradoxes evident in the theory and practice of dream interpretation. These relate to the considerable value afforded to dreams in psychoanalytic thinking, compared with (1) the surprising dearth of literature, research, and training on dream interpretation in clinical practice, (2) the difficulties voiced by clinicians regarding dream interpretation, and (3) the diversity of keys employed by different schools to unlock the ‘truth’ of dreams. The intention of the study is to examine these paradoxes in order to develop a model fordream interpretation which falls within the ambit of psychodynamic psychotherapy. It is argued that there have been few insights over the century to match the seminal work of Freud (1900/1976), except perhaps the work of Carl Jung. As a result of the 1914 rift between these two, Jung’s insights have been largely ignored in mainstream psychoanalytic thinking and the focus on dreams has given way to other areas of development, such as, unconscious thinking, symbol formation, and interpretation in a general sense. These, it is argued, have contributed to a more comprehensive understanding of dreams and their interpretation. Thus a model would need to consider both Freud and Jung’s work, and later salient developments. It would also need to be informed by local, contemporary practice. The method used in this thesis is one of breaking down the process of dream interpretation into component parts, in order to examine useful contributions from different sources and to compare work with dreams to work with other material. The literature review examines the major theoretical contributions in relation to four elements of dreams interpretation: the nature and function of dreams, methods of dream interpretation, the meaning of dreams, and the goals of dream interpretation. A model which accommodates diverse theories without resorting to eclecticism is then proposed. Dream interpretation is further examined in the light of a multiphase clinical study, designed to provide different perspectives on the topic. The study yielded findingscompatible with the literature reviewed, as well as certain problems in relation to the proposed model. These included shortcomings of the elements used in the literature review, particularly the sequence of these elements, and caveats about affording dreams a special focus in the consulting room. Thus a second configuration was posited, namely the idea of viewing dream-work as a triangular situation, comprising the dream, the dreamer, and the dream interpreter. The final model which is the outcome of the study provides two interrelated methods of addressing dream interpretation which accommodate the theory/practice dichotomy. In the first, the elements of dreams and their interpretation are considered sequentially. This method provides a framework for considering theoretical contributions on dreams, as well as issues of technique, without recourse to the introduction of theory in the consulting room. In the second, dream interpretation is regarded as a triangular situation, comprising the interchange between therapist and patient in relation to the patient’s dream-life. This structure accommodates the alliance which is discernible in practice and draws on Segal’s (1957/1986) notion that the process of symbol formation is a triangular situation. The value of regarding ‘dream-work’ in the consulting room as a triangular situation is threefold: (1) it is akin to symbol formation in terms of the meaning reached; (2) dreams cannot be accurately interpreted in isolation from the contributions of both therapist and patient; and (3) it provides ‘dream-work’ in practice with its own structure, highlighting a perspective that dreams are an element of clinical practice, rather than a focus, a subtext within the broader framework of psychodynamic psychotherapy.
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Date Issued: 2001

Ellipsis in the vP domain in Mandarin and Xhosa

Authors: Ma, Xiujie
Date: 2017
Subjects: Grammar, Comparative and general -- Ellipsis , Chinese lanaguage -- Ellipsis , Chinese lanaguage -- Grammar, Comparative -- Xhosa , Xhosa lanaguage -- Ellipsis , Xhosa lanaguage -- Grammar, Comparative -- Chinese
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/43105 , vital:25266
Description: This thesis provides a unified analysis of ellipsis in the vP domain in two typologically different languages, Mandarin and Xhosa from a generative perspective. It starts with the V-stranding Verb Phrase Ellipsis (VPE) assumption and shows that Mandarin and Xhosa do not have V-stranding VPE. The evidence for this is that in both languages, the constituents that remain in vP obligatorily are not allowed to be deleted, whereas the ones that can/must move out of vP can be deleted. The deleted constituents display the characteristics of PF-deletion, i.e. they have an internal syntactic structure. Based on the parallel between movement and ellipsis of the vP-internal constituents, I propose the Ellipsis EPP Hypothesis to account for ellipsis in the vP domain. The Hypothesis predicts that there is an Ellipsis Phrase at the left periphery of vP. The EP bears an Ellipsis-EPP (EEPP) feature, which must be satisfied. Maximal phrases in the c-command domain of EP are all potential candidates for satisfying the EEPP feature by moving to [Spec, EP]. However, only the phrases that are allowed to move out of vP can move to [Spec, EP] as EP is located above vP. Moreover, the movement to [Spec, EP] is subject to the syntactic and semantic restrictions in structure-building in that ellipsis is one operation in the course of structure-building and the derivation will continue after ellipsis takes place. The EEPP feature renders an XP in the specifier phonetically empty and syntactically frozen; therefore, a constituent will be deleted as soon as it moves to [Spec, EP]. The Hypothesis is schematically represented below. The Ellipsis EPP Hypothesis adequately accounts for the ellipsis of various vP-internal constituents - NPs, DPs, infinitive complements and CP complements - in both Mandarin and Xhosa. At the same time, it reveals the reasons why vP is precluded from being elided in these two languages. In Mandarin vP moves to [Spec, AspPi] to check the uninterpretable [asp] feature and in Xhosa vP moves to [Spec, FocP] to realize the focus; consequently, vP may not move to [Spec, EP] for ellipsis.
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Date Issued: 2017

Empathy in the time of ecological apartheid : a social sculpture practice-led inquiry into developing pedagogies for ecological citizenship

Authors: McGarry, Dylan Kenneth
Date: 2014
Subjects: Education -- Philosophy , Social learning , Environmental education , Arts in education
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:1985 , http://hdl.handle.net/10962/d1013154
Description: Considering the ecological crisis and the increased disconnection between human beings and nature, this study attempts to find the social and aesthetic educational response needed for developing ecological citizenship for the 21st century. In this transdisciplinary study I articulate what at first seems a clumsy attempt to enable the capacities of the embodied ecological citizen, and which later emerges as an alchemical ‘social sculpture’ approach to learning that expands the range of capacities available to the citizen and the citizen’s immediate community. This learning bridges the gap between purely biocentric and technocentric forms of education, and addresses the ambiguity of concepts and forms of action such as ‘sustainability’. My primary focus is enabling both communal and personal forms of agency: new ways of 'doing’ and 'being' in the world as it changes radically. I argue that this demands constantly reflecting on and engaging without understanding, place and perception of the problems we see. Attending to a call for the importance of complex learning processes, that deepens our understanding of sustainability, and the need for methodological and pedagogical approaches to accessible forms of learning socially in the era of climate change and environmental degradation, this study offers a particular insight into the education of an ecological citizen. In particular I examine a form of learning that enables individuals to explore relationships between themselves and their ecologies (both physical and social), and that encourages personal forms of knowing so that each person’s values can be cultivated within the experience and intuitive expression from both inner and outer realities. Central to my research focus is addressing the difficulties inherent in ‘ecological apartheid’, which is defined as a growing separation of relationships that include the human being’s relationship with the natural world, as well as disconnections experienced within one’s own inner and outer capacities. Subsequently I investigate forms of learning that encourage agency that most appropriately enable citizens to respond personally to both inner and outer forms of disconnection. ‘Personal’ and ‘relational agency’ are defined and investigated through an initial twelve-month collaborative participatory contextual profiling exploratory research period in South Africa (phase A), where I explore various forms of multiple-genre creative social learning practice that develop an accessible set of methodologies and pedagogies for the ecological citizen. Through this exploratory research, I place significance in the relatively unknown field of social sculpture, which I investigate through a self-made apprenticeship with Shelley Sacks, an expert in the field. This is documented through a rigorous ethnographic inquiry over a period of 18 months. Following this I undertake another two-year collaborative, practice-based research study across South Africa (phase B: 17 towns, with a total of 350 citizens) and eventually abroad (United Kingdom, Germany, USA and Belgium).The focus of this study was the implementation of a collaboratively developed citizen learning practice entitled Earth Forum developed by Shelley Sacks as a progression from her work “Exchange Values: voices of insivible lives” and my collaboative exploration into Earth Forum and its further development draws heavily from social sculpture methods obtained during the apprenticeship, and applied in 36 different incidences. I further explore the efficacy of this practice in enabling and expanding the capacities of participants, particularly those that encourage the development of personal and relational agency. This was achieved through a pedagogical development and expansion period (phase C). A primary finding through the iterative phase (phase D) was the value of imaginal contemplation, attentive listening, and empathy as capacities that enable an ecological citizen’s overall capability. I ascribed this to Nussbaum and Sen’s (1993) capability theory and the need to enable the articulation and implementation of a citizen’s valued ‘beings and doings’. Through this iterative phase, specific attention is given to listening and intuitive capacities in enabling personal and relational agency, and specifically I observed the fundamental role of imagination in this form of learning. Particularly valuable for the educational contribution of this study is the pedagogical development of the Earth Forum practice that enables an accessible, socially constructed form of learning. This contributes specifically to exploring ‘how’ social learning is undertaken, and I argue that an aesthetic approach to learning is vital for the education of the ecological citizen. I carefully describe how one can conduct collaborative practice-based research that utilises creative connective practice in agency development. This collaborative approach, with regard to learning socially and capacity development for ecological citizenship (that focuses its attention on addressing ecological apartheid and separateness), is articulated through a multiple-genred text. I found that empathetic capacity in ecological citizen education is relatively unexplored, and within listening and as well in empathy theory, that the role of imagination in listening and empathy development, requires greater attention. I attempt to reveal how connective practice considers aesthetic form and shape in expanding capacities of human beings, and introduce novel expanded forms of developing pedagogies that encourage personal and relational agency in the context of ecological apartheid from the artsbased field of social sculpture. Finally, I aim in this study to share the potential value found in social sculpture theory and practice into the field of environmental education and social learning through a reflection on the current context of education and social learning, and its potential enrichment via social sculpture processes.
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Date Issued: 2014

Enabling reflexivity and the development of reflexive competence within course processes: a case study of an environmental education professional development course

Authors: Raven, Glenda C
Date: 2005
Subjects: Rhodes University / Gold Fields Course in Environmental Education Environmental education -- Research -- South Africa Environmental education -- South Africa -- Curricula Competency-based education -- South Africa Education and state -- South Africa Education -- Research
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:1507 , http://hdl.handle.net/10962/d1003389
Description: This research was undertaken in the context of socio-economic transformation in South Africa, and more specifically, in the context of change in education policy. To support socio-economic transformation in South Africa after the first democratic elections in 1994, a competence-based National Qualifications Framework (NQF) was introduced in 1995. In responding to the particular socio-historical context of South Africa, the South African NQF is underpinned by the notion of applied competence, integrating practical, foundational and reflexive competence, which is the key and distinguishing feature of this competence-based framework. In this context of transformation, the research was aimed at an in-depth exploration of the notion of reflexivity and reflexive competence, and course processes that enable its development, with a view to providing curriculum development insights for learning programme development in the competence-based NQF, more broadly, and environmental education professional development programmes, more specifically. To enable these aims, the research was undertaken in the context of the Rhodes University / Gold Fields Participatory Course in Environmental Education (RU/GF course), as a case example of a professional development course that aims to develop critically reflexive practitioners. Within an interpretivist orientation, a multiple-embedded case study approach was used to gain insight into the relationship between course processes, reflexivity and the development of reflexive competence to clarify and provide a critical perspective on how competence develops in the context of the course. Data was collected over a period of one year using observation, interviewing and document analysis as the primary data collection techniques. Data was analysed through various phases and layers to inform data generation and the synthesising of data for further interpretation. Through the literature review undertaken within the study, various significant insights emerged around the notion of reflexivity and reflexive competence. Firstly, there appears to be a need to distinguish between reflexivity as social processes of change (social actions and interactions within social systems, structures and processes) and reflexive competence (a range of integrative elements of competence) that provides the evidence of an engagement within social processes of change. The second key insight emerging is the significance of social structure in shaping participation in reflexive processes, thus emphasising the duality of structure as both the medium for, and outcome of reflexive social actions and interactions and so challenges the deterministic conception of social structure. Further, the significance of an epistemologically framed notion of reflexivity and reflexive competence emerged, in the context of responding to the complex and uncertain quality of socio-ecological risks and in supporting change in context. Reflexivity, distinguished from processes of critical reflection, foregrounds a critical exploration of both knowledge and unawareness. As such a reinterpretation of reflexive competence is offered as a process of potential challenge to dominant and reigning forms of reasoning (knowledge frameworks) and consequent principles of ordering. Through this reframing of reflexive competence, the potential exists to destabilise dominant forms of reasoning and principles of ordering to create a broader scope of possibilities for action and change in context. This reframing of reflexive competence in the context of transformation in South Africa has critical implications for engaging within processes of learning programme design in the NQF to support an engagement within reflexive processes of change and the development of a range of integrative elements of reflexive competence. In this light, the study attempts to make the following contribution to curriculum deliberations within the context of environmental education and the NQF in relation to reflexivity, reflexive competence and change: ♦ Reflexivity is conceptualised as social processes of change with reflexive competence providing evidence of engagement within these social processes of change; ♦ An epistemologically framed conception of reflexivity and reflexive competence recognises how rules of reason and the ordering of the ‘reasonable’ person come to shape social life; and so ♦ Change is conceptualised as ruptures and breaks in dominant knowledge frames and the power relations embedded in these; ♦ Unawareness emerges as a key dimension within reflexive environmental education processes in responding to the unpredictable and uncertain nature of risks; ♦ An epistemological framing of reflexivity and reflexive competence highlights the need to develop open processes of learning to support the critical exploration of knowledge and unawareness; and ♦ Within this framing of reflexivity and reflexive competence, the difficulty emerges in specifically predefining reflexive competence to inform standard setting processes within a context of intended change. In framing data within this emerging conception of reflexivity and reflexive competence, a review of course processes highlighted potential areas for reorienting the RU/GF course to support change in context, for which I make specific recommendations. Drawing on the review of course processes in the RU/GF course, and in light of the reframing of reflexivity and reflexive competence, I further offer summative discussions as ‘possible implications’ for learning programme design in the South African competence-based NQF, broadly and environmental education professional development programmes in this framework, more specifically.
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Date Issued: 2005

Engel en aarde : gedagtes oor "natuur en bo-natuur" by die lees van Sheila Cussons

Authors: De Villiers, Johanna Helena
Date: 1985
Subjects: Cussons, Sheila -- Criticism and interpretation
Language: Afrikaans
Type: Thesis , Doctoral , PhD
Identifier: vital:3619 , http://hdl.handle.net/10962/d1006960
Description: Hierdie studie is In poging om uit die veelgeskakeerde digwerk van Sheila Cussons een draad te neem en dit deur te volg; in die hoop dat dit 'n Ariadne-draad mag word tot beter besef van die ryk gestruktureerdheid en diepte van haar verwysingsveld, en die betekenis daarvan vir ons tyd. Dis dan primer die beeld van die engel wat nagespeur word, as bonatuurlike wese wat nie tot die vlak van die fisiese inkorporeer nie. (From Ch. 1)
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Date Issued: 1985

English first additional language teachers' understanding and implementation of reading strategies in senior classes of Mthatha District : South Africa

Authors: Madikiza, Nophawu
Date: 2017
Subjects: Reading (Secondary English language -- Study and teaching English language
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10353/6422 , vital:29671
Description: Reading is a skill that teachers have to enthusiastically teach to encourage learning of complex set of reading skills, knowledge and understanding. Teaching of reading strategies to students to improve their reading ability is very important. However, surveys conducted in South Africa during 2001 and 2004 by the Department of Basic Education to establish literacy and numeracy levels in primary schools showed shockingly low levels of reading ability across the country. Therefore, the purpose of this study was to ascertain English First Additional Language teachers’ understanding and implementation of reading strategies. Obtaining teachers’ perceptions and challenges on reading strategies was vital for this study as a way of establishing their competency towards teaching reading. Four research questions were sought to determine namely; reading strategies currently adopted by teachers in their classes, teachers’ perceptions of reading strategies, reading problems or challenges that teachers were facing. A mixed method research was chosen for this study which involves both the qualitative and quantitative approaches. The study followed a survey research design and a case study research design. A purposive sampling was used to select 126 teachers from which questionnaires were administered to collect data and 10 teachers were randomly drawn from the sample to be interviewed and observed in class. Both qualitative and quantitative data were analysed concurrently using coding and categorization of themes for qualitative data and Statistical Package for Social Sciences (SPSS) for quantitative data. The results indicated that a majority of teachers seemed not to understand and implement certain reading strategies and there were few teachers who asserted to the understanding and implementation of these strategies. The teachers mentioned that they were not trained continuously on reading strategies and the schools had no libraries. A majority of teachers highlighted that there were indeed problematic reading strategies and they simply did away with the strategies that were not suitable for their learners and would try the ones they found relevant or suitable. The study presents a proposed reading enhancement model to assist teachers in the teaching of reading. English First Additional Language teachers may benefit from the model and incorporate some or all of the aspects to develop their reading strategy use programmes.
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Date Issued: 2017

Enhancing the role of the Kaizen suggestion tool in South African lean automotive companies of the Eastern Cape

Authors: Adedeji, Adeyemi Charles
Date: 2011
Subjects: Lean manufacturing , Manufacturing processes , Production management -- Mathematical models
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:8644 , http://hdl.handle.net/10948/d1008157 , Lean manufacturing , Manufacturing processes , Production management -- Mathematical models
Description: The Toyota manufacturing system, aptly referred to as Lean manufacturing, has received a reasonable appreciation and awareness over the past decade in South African industry. This production phenomenon constitutes an organizational culture that encourages world-class production success through the liberation of factory resources, while employees are empowered and encouraged to contribute ideas for the improvement of processes and products. However, despite lean awareness and the crucial role of employee participation in the suggestion of ideas in world-class organizations, the performance level of lean manufacturing in South African industry is largely devoid of the Kaizen suggestion tool, particularly in the automotive companies of the Eastern Cape. The aim of this research was to proffer appropriate recommendations, improved awareness, understanding and practice for the improvement of the Kaizen suggestion principle in the automotive companies of the Eastern Cape. The research primarily focused on the ‘management/employees’ paradigm within the organisational context. The methodology employed in the study included a thorough review of the relevant literature and a questionnaire, which was developed and administered to both the management and employees of the thirty automotive components suppliers in Eastern Cape. The target companies constituted the units of analyses and therefore provided the opportunity for a detailed investigation of the links between management and employees as well as a submission of ideas for operational and organisational processes as established in the literature review. Epistemologically, the research is objectivist and paradigmically, positivist. However, some qualitative aspects of the data were relevant to the study and, therefore, were used in a complementary manner. The case approach utilized mixed methods by applying a range of data collection techniques and evidence from multiple sources while the sampling technique was sequential, involving both purposive and stratified random sampling. The study reveals the apparent lack of a systematic mechanism for the practice and administration of the Kaizen suggestion tools in most Eastern Cape automotive companies. This demerit is found to have negatively affected maximum employee participation and involvement in organizational decision making within the Province. The study has established a basic level of awareness and understanding among employees / employers relations that the Kaizen suggestion scheme is a vital tool for delivering strategic objectives in the management of decision making and organizational growth. The study strongly advocates the inclusion of employee suggestion systems as part of the organizational process.
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Date Issued: 2011

Environmental conflict resolution: a critical analysis of the role of interests and value

Authors: Mweshi, John
Date: 2015
Language: English
Type: text , Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/55842 , vital:26740
Description: This thesis intends to contribute to an enhanced understanding of environmental conflicts and their resolution. To accomplish this task the thesis will ascertain the role that value and interests play in environmental conflicts in order to establish an adequate basis upon which they can be resolved. In the process, the thesis will also examine three different approaches, namely, the Standard Approach; the Environmental Impact Assessment (EIA) framework; and the Structured Decision Making (SDM) approach. First, the standard approach is informed by the understanding that focusing on interests instead of human values makes the resolution of conflicts more tractable. In contrast, this thesis argues that an exclusive focus on interests, in the context of environmental conflict resolution, is inadequate in some important respects because there are other factors to be considered such as the environmental impacts at the root of the conflict. Second, the thesis examines the focus on impacts that characterises EIAs. It argues that this approach remedies the limitations of the standard approach insofar as impacts are understood in terms of object value. However, the EIA approach does not provide much guidance on how to deal with conflicting human values. Third, taking into account the fact that the standard approach does not address the question of object value, while the EIA addresses object value but does not deal directly with human values, the thesis examines the SDM approach to environmental risk decisions. The thesis argues that while the SDM approach claims to deal with conflicts involving human values head-on, it does not provide a viable alternative in terms of environmental conflict resolution. This is because it fails to recognise the key distinction between human values and object value despite acknowledging the presence of multiple value dimensions as a major obstacle to value trade-offs and therefore to the resolution of value conflicts. Finally, the thesis recommends an adequate basis upon which environmental conflicts can be resolved.
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Date Issued: 2015

Environmental management in military activities of the South African National Defence Force

Authors: Magagula, Hezekiel Bheki
Date: 2016
Subjects: South Africa -- South African Defence Force Military bases -- Environmental aspects Hazardous waste site remediation
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10353/5927 , vital:29430
Description: This thesis presents research findings on current environmental management practices used by the South African National Defence Force (SANDF). Two case studies are presented; the first is the Grahamstown Military Installation (6 South African Infantry Battalion) and the second the South African Army Combat Training Centre (42 Brigade). A combination of three sampling techniques, namely, the stratified, purposive and link-tracing (snowball) samplings were employed and structured questionnaires and semi-structured interviews with key SANDF officials were used as primary data. In addition, secondary data sources in the form of inter alia the first and second editions of the Environmental Management Plan for Defence (2001 & 2008 respectively); the development and implementation of environmental education and training in the military: a joint United States-Republic of South Africa Environmental Working Group Project (2003); Overarching Strategic Statement for 2011; Integrated Environmental Management Information Series: Linking Environmental Impact Assessment and Environmental Management Systems (2004); The Department of Defence Strategic Plan (2010): Republic of South Africa and the South African Defence Review (2012) were studied. In addition, field observations were also carried out within the two military installations training areas between July, 2011 and November, 2013. Primary data on the conditions of training areas, waste removal after training exercises, pollution prevention measures, and rehabilitation efforts to restore degraded training ranges were collected. Furthermore, composite surface sediment samples and water samples were collected for analysis. A total of fifty-six surface sediments and thirty water samples were analysed for the concentrations of heavy metals using the ICP-MS. These attitudes and perceptions are predominantly positive. Statistical analysis (ANOVA) did not reveal any significant differences in responses, especially, between military ranks. However, sporadic significant differences were found in five of the statements in the questionnaire from respondents with different service periods. Furthermore, the emphasis placed on environmental protection within defence force activities worldwide has compelled the South African Department of Defence and Military Veterans (DoDMV) to regulate the management of the environment within its properties. Yet, these efforts have faced numerous challenges ranging from financial to human resource deficiencies. It was found that environmental management practices and programmes at different military installations vary significantly. Consequently, six environmental management programmes were identified at South African Army Combat Training Centre, while only one environmental management programme was identified at Grahamstown Military Installation. This programme is a collaborative effort between the SANDF/DoDMV and the Department of Water Affairs and Sanitation to eradicate invasive alien plant species. In the light of the analysis of official documents and interviews with respondents, it was established that the DoDMV does not have a budget for environmental management services and environmental management is yet to be incorporated into formal military training programmes. There is a severe shortage of environmentally qualified and knowledgeable personnel within the SANDF. Subsequently, all these drawbacks lead to the failure of the implementation of the Defence Force’s Environmental Management System (EMS) and inadequate management of the environment at military installations of the SANDF. Consequently, these challenges have severely compromised the commitment of the SANDF to honour its environmental management obligations. Such deficiencies tend to undermine the sustainable utilisation of the national assets entrusted to the Defence Force. Therefore, this thesis argues that environmental management programmes for the SANDF are based on a very weak foundation. This thesis proposes an ideal model for the successful implementation of the EMS and management of the environment at SANDF military installations. The analysis of water and soil samples led to the identification and quantification of heavy mental pollutants. The concentrations of heavy metals in water samples were varying between <0.01 to <0.05mg/l, but generally constant. Thus, no significant or meaningful statistical results were obtained. Pearson’s correlation coefficient was used to analyse the concentrations of heavy metals obtained in the sediment samples.
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Date Issued: 2016

Establishing a formulation design space for a generic clobetasol 17- propionate cream using the principles of quality by design

Authors: Fauzee, Ayeshah Fateemah Beebee
Date: 2014
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:20983 , http://hdl.handle.net/10962/5868
Description: The pharmaceutical industry is global, is highly regulated and is able to achieve reasonable product quality but at high cost with maximum effort. Numerous challenges face the pharmaceutical industry and include a shrinking research pipeline, less innovation, outsourcing, investments, increasing research and development costs, long approval times, growth of the generic industry, failure to understand or analyze manufacturing failure and wastage as high at fifty percent for some pharmaceutical products. An efficient and flexible pharmaceutical sector should be able to consistently produce high quality pharmaceutical products at a reduced cost with minimal waste. As a result, Food and Drug Administration (FDA) and other agencies such as the International Conference on Harmonization (ICH) have embraced a “Quality by Design” (QbD) paradigm and this has become the “desired state” so as to shift manufacturing from being empirical to a science, engineering, and risk based approach. QbD is a systematic approach for the development of high quality pharmaceutical dosage forms that begins with predefined objectives based on the premise that quality must be built into and not tested into a product. QbD together with the establishment of a design space for dosage forms is a fairly new concept and there is limited published data on QbD concepts that report the entire process of identifying Critical Quality Attributes (CQA), design of a formulation and manufacturing process to meet product CQA, understanding the impact of material attributes and process parameters on product CQA, identification and controlling sources of variability in materials and processes that affect the CQA of a product and finally establishing, evaluating and testing a design space using both in vitro and in vivo approaches to assure that a product of consistent quality can always be produced. The objective of these studies was to implement a QbD approach to establish a design space for the development and manufacture of a safe, effective, stable generic formulation containing 0.05% w/w clobetasol 17-propionate (CP) that had similar in vitro and in vivo characteristics to an innovator product, Dermovate® (Sekpharma® Pty Ltd, Sandton, Gauteng, RSA). Such a product would pose a minimal risk of failure when treating severe skin disorders such as seborrhoeic dermatitis, extreme photodermatitis and/or severe psoriasis in HIV/AIDS patients in Southern Africa.
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Date Issued: 2014

Estuarine-dependency and multiple habitat use by dusky kob Argyrosomus Japonicus (Pisces: Sciaenidae)

Authors: Childs, Amber-Robyn
Date: 2013
Subjects: Argyrosomus -- Habitat -- South Africa -- Algoa Bay , Argyrosomus -- Behavior -- South Africa -- Algoa Bay , Argyrosomus -- Migration -- South Africa -- Algoa Bay , Estuarine fishes -- South Africa -- Algoa Bay , Habitat selection -- South Africa -- Algoa Bay , Argyrosomus -- South Africa -- Sundays Estuary (Eastern Cape) , Underwater acoustic telemetry
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:5386 , http://hdl.handle.net/10962/d1020241
Description: Dusky kob Argyrosomus japonicus is a wide-ranging estuarine-dependent Sciaenid and an important fishery species throughout most of its distribution. It is one of South Africa’s most valuable coastal fishery species. High levels of juvenile exploitation in estuaries and ineffective management regulations have led to stock collapse, highlighting the need to better understand the spatial and temporal aspects of estuarine-dependency and multiple habitat use. Habitat connectivity is a critical property of estuarine-associated fishes and it therefore follows that knowledge of this link is fundamental in understanding population dynamics and the nursery role of estuarine and/or marine habitats. While dusky kob occur in both estuaries and nearshore coastal zones, limited information on connectivity among these habitats exists. The aim of this study is to assess the role of estuarine nursery habitats in the life cycle of the dusky kob by examining multiple habitat connectivity and determining the drivers associated with estuarine use. A total of 96 dusky kob (237–1280 mm total length) were tagged with acoustic transmitters in both the estuarine and marine environments of Algoa Bay, Eastern Cape, South Africa between May 2008 and September 2010. Their movements were monitored using a network of automated data-logging acoustic receivers deployed in the Sundays Estuary, seven neighbouring estuarine habitats, two commercial harbours and various sites within Algoa Bay. And more...
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Date Issued: 2013

Showing items 161 - 180 of 535

Ecology and degree of specialization of South African milkweeds with diverse pollination systems

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)

Ecology of key cerithioidean gastropods in the mangroves of the iSimangaliso Wetland Park, KwaZulu-Natal South Africa

Ecosystem services in a biosphere reserve context: identification, mapping and valuation

Effect of increasing fossil shell flour levels on digestive and metabolic utilization, health, body weight change and wool production, and quality in Dohne-Merino wethers

Effects of lethal management on black-backed jackal population structure and source-sink dynamics

Effects of sustained Russian wheat aphid (Diuraphis noxia Mordvilko) feeding on leaf blades of wheat (Triticum aestivum L. cv Adamtas)

Effects of temperature on the development, behaviour and geography of blowflies in a forensic context

Elasticity of the South African economy towards portfolio investments in BRICS countries

Elements of dream interpretation: laying the foundation of a basic model for clinical practice

Ellipsis in the vP domain in Mandarin and Xhosa

Empathy in the time of ecological apartheid : a social sculpture practice-led inquiry into developing pedagogies for ecological citizenship

Enabling reflexivity and the development of reflexive competence within course processes: a case study of an environmental education professional development course

Engel en aarde : gedagtes oor "natuur en bo-natuur" by die lees van Sheila Cussons

English first additional language teachers' understanding and implementation of reading strategies in senior classes of Mthatha District : South Africa

Enhancing the role of the Kaizen suggestion tool in South African lean automotive companies of the Eastern Cape

Environmental conflict resolution: a critical analysis of the role of interests and value

Environmental management in military activities of the South African National Defence Force

Establishing a formulation design space for a generic clobetasol 17- propionate cream using the principles of quality by design

Estuarine-dependency and multiple habitat use by dusky kob Argyrosomus Japonicus (Pisces: Sciaenidae)