The petrology and significance of a stratiform mafic segregation pegmatite in a Karoo-aged dolerite sheet
- Mitchell, Andrew A, Naicker, S B, Marsh, Julian S, Dunlevey, J N
- Authors: Mitchell, Andrew A , Naicker, S B , Marsh, Julian S , Dunlevey, J N
- Date: 1997
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149496 , vital:38858 , https://hdl.handle.net/10520/EJC-9293fd659
- Description: A sub-horizontal stratiform mafic segregation pegmatite, of the order of 30 cm thick, occurs within 25 m of the top contact of a Karoo-aged dolerite sheet at Pietermaritzburg, South Africa. The host rock is an orthopyroxene-rich dolerite containing 5 - 8% interstitial granophyre. The pegmatite is similar to the host dolerite in many respects, except that the granophyre content is higher, and acicular augite is the only pyroxene. At its upper contact, a laterally continuous sub-horizontal joint forms a sharp boundary to the pegmatite, whilst the lower contact is gradational over a few millimetres. Low MgO and chalcophiles, and elevated incompatible element contents, are the main geochemical attributes of the pegmatite.
- Full Text:
- Date Issued: 1997
- Authors: Mitchell, Andrew A , Naicker, S B , Marsh, Julian S , Dunlevey, J N
- Date: 1997
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149496 , vital:38858 , https://hdl.handle.net/10520/EJC-9293fd659
- Description: A sub-horizontal stratiform mafic segregation pegmatite, of the order of 30 cm thick, occurs within 25 m of the top contact of a Karoo-aged dolerite sheet at Pietermaritzburg, South Africa. The host rock is an orthopyroxene-rich dolerite containing 5 - 8% interstitial granophyre. The pegmatite is similar to the host dolerite in many respects, except that the granophyre content is higher, and acicular augite is the only pyroxene. At its upper contact, a laterally continuous sub-horizontal joint forms a sharp boundary to the pegmatite, whilst the lower contact is gradational over a few millimetres. Low MgO and chalcophiles, and elevated incompatible element contents, are the main geochemical attributes of the pegmatite.
- Full Text:
- Date Issued: 1997
The effect of elevated CO₂ on Phaseolus vulgaris L. cv Contender
- Authors: Mjwara, Jabulani Michael
- Date: 1997
- Subjects: Plants -- Effect of carbon dioxide on Kidney bean
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4215 , http://hdl.handle.net/10962/d1003784
- Description: The response of Phaseolus vulgaris L. cv. Contender grown in controlled environmental conditions, at either ambient or elevated (360 and 700 μmol mol ̄¹, respectively) CO₂ concentrations ([CO₂]), was monitored from 10 days after germination (DAG) until the onset of senescence. Elevated CO₂ had a pronounced effect on total plant height (TPH), leaf area (LA), dry weight (DW) accumulation and specific leaf area (SLA). All of these were significantly increased by elevated [CO₂] with the exception of SLA, which was significantly reduced. Except for higher initial relative growth rates (RGR) in CO₂-enriched plants, RGR did not differ significantly between the two CO₂ treatments throughout the remainder of growth period. While growth parameters clearly differed between CO₂ treatments, the effects of CO₂ on many physiological processes including net assimilation rate (NAR), Rubisco activity, and some foliar nutrient concentrations were largely transient. For example, CO₂ enrichment significantly increased NAR, but from 20 DAG onward, NAR declined to levels measured on plants grown under ambient CO₂. Similarly, the decline in both foliar N concentration and Rubisco activity in CO₂-enriched plants after 20 DAG was significantly greater than the decline observed for ambient CO₂ plants. Soluble leaf protein and total chlorophylls (a+b) were also significantly reduced in plants grown under elevated CO₂. Chlorophyll (a/b) ratios increased with time underelevated CO₂, indicating that the rate of decline of chlorophyll b was higher than that of chorophyll α. No significant changes in total carotenoid (x+c) levels were observed in either CO₂ treatment. Under enhanced CO₂, the foliar concentrations of K and Mn were increased significantly, while P, Ca, Fe and Zn were reduced significantly. However, changes in Mg and Cu concentrations were not significant. High CO₂-grown plants also exhibited pronounced leaf discoloration or chlorosis, coupled with a significant reduction in leaf longevity. The levels of non-structural carbohydrates (sucrose, glucose, fructose and starch) and nitrogenous compounds (nitrogen, total soluble proteins and free amino acids) were determined for leaves and developing seeds of P. vulgaris. Leaf tissue of elevated CO₂-grown plants accumulated significantly higher levels of both soluble sugars and starch. Leaf ultrastructure revealed considerable erilargement of starch grain sizes with surface areas more than five times larger compared to those of control plants. No apparent differences in structure and membrane integrity of chloroplasts in both CO₂ treatments were noted. Although ambient CO₂-grown plants had comparatively low levels of non-structural carbohydrates (NSC), they accumulated significantly higher levels of nitrogenous compounds. The levels of NSC were consistently higher in seeds of plants grown under elevated CO₂. In comparison to plants grown at elevated [CO₂], pods and seeds of ambient CO₂-grown plants had significantly larger pools of free amino compounds and N. Stomatal conductance (gs) declined significantly, as expected for plants grown under elevated CO₂. This was accompanied by a decline in transpiration rates (E). Reduced gs and E led to high AlE ratio, which meant improved water use efficiency (WUE) values for CO₂-enriched bean plants. Leaf carbon isotope discrimination (∆) against the heavier isotope of carbon (¹³C), has been used to select for high WUE in C₃ plants. In plants grown at elevated CO₂ concentration, ,1 was significantly reduced. Although ∆ was negatively correlated with WUE in both CO₂ treatments, the correlation was steeper and highly negative for CO₂-enriched plants. These results indicate underlying differences in gas-exchange physiology, including stomatal responses between ambient and elevated CO₂-grown plants. Photosynthetic acclimation was investigated using the response of assimilation to internal carbon dioxide concentration (A/C₁ curves). At early stages of growth, the initial slope of the A/C₁ response curve did not differ with CO₂ treatment. In contrast, CO₂-saturated photosynthetic rate (Amax) was significantly higher in plants grown under elevated versus ambient CO₂ at 15 DAG. However, at subsequent stages of growth both the initial slope and Amax declined in bean plants grown in elevated CO₂. Apparent carboxylation efficiency (ACE, estimated from the initial slope of A/C₁ response) values followed a similar trend and were significantly reduced in CO₂-enriched plants. These results indicate that acclimation or negative adjustment of photosynthesis may have been caused by a combination of both stomatal and biochemical limitations. Bean plants grown under conditions of elevated atmospheric CO₂ flowered 3 to 4 days earlier, and produced significantly more flowers and pods than plants grown at ambient conditions. Plants grown at elevated CO₂ aborted 22 and 20% more flowers and pods, respectively, than plants grown at ambient CO₂. Elevated CO₂ also significantly increased the number of tillers or lateral branches produced by plants, which contributed to a significant increase in pod number and seed yield in these plants. Although plants grown at elevated CO₂ produced on average 8 seeds per pod, while plants grown under ambient CO2 conditions produced 5 seeds per pod, the greater number of seeds was offset by lower seed weights in plants grown under _ elevated CO₂. Thus, despite high seed yield in beans grown under elevated CO₂, the harvest index (HI) did not change significantly between CO₂ treatments.
- Full Text:
- Date Issued: 1997
- Authors: Mjwara, Jabulani Michael
- Date: 1997
- Subjects: Plants -- Effect of carbon dioxide on Kidney bean
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4215 , http://hdl.handle.net/10962/d1003784
- Description: The response of Phaseolus vulgaris L. cv. Contender grown in controlled environmental conditions, at either ambient or elevated (360 and 700 μmol mol ̄¹, respectively) CO₂ concentrations ([CO₂]), was monitored from 10 days after germination (DAG) until the onset of senescence. Elevated CO₂ had a pronounced effect on total plant height (TPH), leaf area (LA), dry weight (DW) accumulation and specific leaf area (SLA). All of these were significantly increased by elevated [CO₂] with the exception of SLA, which was significantly reduced. Except for higher initial relative growth rates (RGR) in CO₂-enriched plants, RGR did not differ significantly between the two CO₂ treatments throughout the remainder of growth period. While growth parameters clearly differed between CO₂ treatments, the effects of CO₂ on many physiological processes including net assimilation rate (NAR), Rubisco activity, and some foliar nutrient concentrations were largely transient. For example, CO₂ enrichment significantly increased NAR, but from 20 DAG onward, NAR declined to levels measured on plants grown under ambient CO₂. Similarly, the decline in both foliar N concentration and Rubisco activity in CO₂-enriched plants after 20 DAG was significantly greater than the decline observed for ambient CO₂ plants. Soluble leaf protein and total chlorophylls (a+b) were also significantly reduced in plants grown under elevated CO₂. Chlorophyll (a/b) ratios increased with time underelevated CO₂, indicating that the rate of decline of chlorophyll b was higher than that of chorophyll α. No significant changes in total carotenoid (x+c) levels were observed in either CO₂ treatment. Under enhanced CO₂, the foliar concentrations of K and Mn were increased significantly, while P, Ca, Fe and Zn were reduced significantly. However, changes in Mg and Cu concentrations were not significant. High CO₂-grown plants also exhibited pronounced leaf discoloration or chlorosis, coupled with a significant reduction in leaf longevity. The levels of non-structural carbohydrates (sucrose, glucose, fructose and starch) and nitrogenous compounds (nitrogen, total soluble proteins and free amino acids) were determined for leaves and developing seeds of P. vulgaris. Leaf tissue of elevated CO₂-grown plants accumulated significantly higher levels of both soluble sugars and starch. Leaf ultrastructure revealed considerable erilargement of starch grain sizes with surface areas more than five times larger compared to those of control plants. No apparent differences in structure and membrane integrity of chloroplasts in both CO₂ treatments were noted. Although ambient CO₂-grown plants had comparatively low levels of non-structural carbohydrates (NSC), they accumulated significantly higher levels of nitrogenous compounds. The levels of NSC were consistently higher in seeds of plants grown under elevated CO₂. In comparison to plants grown at elevated [CO₂], pods and seeds of ambient CO₂-grown plants had significantly larger pools of free amino compounds and N. Stomatal conductance (gs) declined significantly, as expected for plants grown under elevated CO₂. This was accompanied by a decline in transpiration rates (E). Reduced gs and E led to high AlE ratio, which meant improved water use efficiency (WUE) values for CO₂-enriched bean plants. Leaf carbon isotope discrimination (∆) against the heavier isotope of carbon (¹³C), has been used to select for high WUE in C₃ plants. In plants grown at elevated CO₂ concentration, ,1 was significantly reduced. Although ∆ was negatively correlated with WUE in both CO₂ treatments, the correlation was steeper and highly negative for CO₂-enriched plants. These results indicate underlying differences in gas-exchange physiology, including stomatal responses between ambient and elevated CO₂-grown plants. Photosynthetic acclimation was investigated using the response of assimilation to internal carbon dioxide concentration (A/C₁ curves). At early stages of growth, the initial slope of the A/C₁ response curve did not differ with CO₂ treatment. In contrast, CO₂-saturated photosynthetic rate (Amax) was significantly higher in plants grown under elevated versus ambient CO₂ at 15 DAG. However, at subsequent stages of growth both the initial slope and Amax declined in bean plants grown in elevated CO₂. Apparent carboxylation efficiency (ACE, estimated from the initial slope of A/C₁ response) values followed a similar trend and were significantly reduced in CO₂-enriched plants. These results indicate that acclimation or negative adjustment of photosynthesis may have been caused by a combination of both stomatal and biochemical limitations. Bean plants grown under conditions of elevated atmospheric CO₂ flowered 3 to 4 days earlier, and produced significantly more flowers and pods than plants grown at ambient conditions. Plants grown at elevated CO₂ aborted 22 and 20% more flowers and pods, respectively, than plants grown at ambient CO₂. Elevated CO₂ also significantly increased the number of tillers or lateral branches produced by plants, which contributed to a significant increase in pod number and seed yield in these plants. Although plants grown at elevated CO₂ produced on average 8 seeds per pod, while plants grown under ambient CO2 conditions produced 5 seeds per pod, the greater number of seeds was offset by lower seed weights in plants grown under _ elevated CO₂. Thus, despite high seed yield in beans grown under elevated CO₂, the harvest index (HI) did not change significantly between CO₂ treatments.
- Full Text:
- Date Issued: 1997
An evaluation of small scale open cast mining of UG2 in the Bushveld complex
- Authors: Mooney, David G
- Date: 1997
- Subjects: Platinum mines and mining -- South Africa , Strip mining -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4943 , http://hdl.handle.net/10962/d1005555 , Platinum mines and mining -- South Africa , Strip mining -- South Africa
- Description: The current weak state of the platinum market, as well as the large inventory of platinum group metals held by Russia, necessitates that the South African platinum mining industry must carefully evaluate the benefits and disadvantage of small-scale mining of shallow, open castable ore resources. Until the late 1980's, these resources were ignored due to the metallurgical complexities of treating oxidized ore, as well as the mind set that existed within the South African mining industry which militated against open cast mining in the Bushveld. During the latter part of the 1980's and early 1990's, advances in the metallurgical treatment of oxidized ore, specifically the UG2, as well as operational problems, created the impetus to begin the exploitation of these resources. Small-scale open cast mining has become viable due to the development of suitable mining methods that facilitate mining practices acceptable to the Department of Mineral and Energy Affairs, in terms of environmental legislation. Metallurgical advances and growing experience, especially with respect to the UG2, enables reasonable platinum group metals recovery from oxidized ore. The problems experienced in doing this can, and are being overcome. With growing public awareness of environmental issues, particularly related to the mining industry, the requirement to ensure that the small-scale open cast mine site is well managed is paramount. A methodology for the evaluation is presented along with a case study of a small-scale UG2 open cast pit. Evidence is presented that shows that these small-scale open cast mining operations are extremely profitable and require minimal capital expenditure. However, caution is advised when evaluating Merensky Reef open cast operations because of the problems that they present.
- Full Text:
- Date Issued: 1997
- Authors: Mooney, David G
- Date: 1997
- Subjects: Platinum mines and mining -- South Africa , Strip mining -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4943 , http://hdl.handle.net/10962/d1005555 , Platinum mines and mining -- South Africa , Strip mining -- South Africa
- Description: The current weak state of the platinum market, as well as the large inventory of platinum group metals held by Russia, necessitates that the South African platinum mining industry must carefully evaluate the benefits and disadvantage of small-scale mining of shallow, open castable ore resources. Until the late 1980's, these resources were ignored due to the metallurgical complexities of treating oxidized ore, as well as the mind set that existed within the South African mining industry which militated against open cast mining in the Bushveld. During the latter part of the 1980's and early 1990's, advances in the metallurgical treatment of oxidized ore, specifically the UG2, as well as operational problems, created the impetus to begin the exploitation of these resources. Small-scale open cast mining has become viable due to the development of suitable mining methods that facilitate mining practices acceptable to the Department of Mineral and Energy Affairs, in terms of environmental legislation. Metallurgical advances and growing experience, especially with respect to the UG2, enables reasonable platinum group metals recovery from oxidized ore. The problems experienced in doing this can, and are being overcome. With growing public awareness of environmental issues, particularly related to the mining industry, the requirement to ensure that the small-scale open cast mine site is well managed is paramount. A methodology for the evaluation is presented along with a case study of a small-scale UG2 open cast pit. Evidence is presented that shows that these small-scale open cast mining operations are extremely profitable and require minimal capital expenditure. However, caution is advised when evaluating Merensky Reef open cast operations because of the problems that they present.
- Full Text:
- Date Issued: 1997
The effects of economic incentives in controlling pollution in the South African leather industry: die uitwerking van ekonomiese insentiewe op die beheer van besoedeling in die Suid-Afrikaanse leerbedryf
- Mowat, Shaun P, Antrobus, Geoffrey G, Fraser, Gavin C G
- Authors: Mowat, Shaun P , Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143057 , vital:38197 , DOI: 10.1080/03031853.1997.9523487
- Description: Pollution of the environment is becoming an increasingly serious problem. A large contributor to this is industry which generates effluent as a by-product of its production process. Two methods of controlling the pollution generated by industry are the so-called “command and control” techniques and economic incentives. In theory, economic incentives promise a more economically efficient and equitable means of pollution control. This paper sets out to ascertain whether this would hold in practice by applying environmental economic theory to the practical problem of controlling the effluent generated by one particular industry, viz the South African leather industry.
- Full Text:
- Date Issued: 2010
- Authors: Mowat, Shaun P , Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143057 , vital:38197 , DOI: 10.1080/03031853.1997.9523487
- Description: Pollution of the environment is becoming an increasingly serious problem. A large contributor to this is industry which generates effluent as a by-product of its production process. Two methods of controlling the pollution generated by industry are the so-called “command and control” techniques and economic incentives. In theory, economic incentives promise a more economically efficient and equitable means of pollution control. This paper sets out to ascertain whether this would hold in practice by applying environmental economic theory to the practical problem of controlling the effluent generated by one particular industry, viz the South African leather industry.
- Full Text:
- Date Issued: 2010
Ecological interaction between the introduced and native rock-dwelling cichlid fishes of Lake Malawi National Park, Malawi
- Authors: Munthali, Simon Muchina
- Date: 1997
- Subjects: Cichlids -- Nyasa, Lake
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5266 , http://hdl.handle.net/10962/d1005110
- Description: More than twenty years ago, over twenty species of the rock-dwelling cichlid species (Mbuna) were translocated from the northern Lake Malawi, where they are endemic, to Thumbi West Island, Lake Malawi National Park, in the southern part of Lake Malawi. Among these species, Cynotilapia afra, Pseudotropheus callainos and Pseudotropheus tropheops 'red cheek' are strongly territorial, and have increased substantially in number and are widely distributed, particularly in the three to seven metre depth band of the rocky habitats at the Island of Thumbi West. It is feared that the increase in population density of translocated species (hereafter referred to as introduced species) may be at the expense of ecologically equivalent native species which could be eliminated. In this thesis the following key hypotheses have been tested: (i) that the introduced species having originated from a region of Lake Malawi which is generally poor in nutrients and introduced in an area which is richer in nutrients, would cope better than the native species during periods of nutrient scarcity which occur frequently, often seasonally in oligotrophic lakes, such as Lake Malawi; (ii) that the introduced species are fitter than their ecologically equivalent native species in the acquisition of territorial space in which they breed, feed and seek shelter, and (iii) that introduced and native species coexist by utilizing different microhabitats. Results show that: 1. the introduced species, P. callainos and P. tropheops 'red cheek' may have responded positively to enhanced nutrient availability, as they were found to have better condition factors and fecundity indices at Thumbi West Island than at sites of their origin, in the northern lake Malawi. Cynotilapia afra, P. callainos and P. tropheops 'red cheek' also maximise their life-span fecundity by starting to reproduce at relatively smaller size than the native species with which they overlap in microhabitat requirements. Similarly, their breeding peaks precede the breeding peaks of the native species with which they overlap in microhabitat requirements. Consequently, due to priority residence effects, the offspring of introduced species may have a competitive edge in the use of essential resources, e.g., refuge over the offspring of the native species whose peak-recruitment occurs later in the year. 2. There is an overlap between the introduced and native species in their microhabitat requirements. Consequently, interference competition between them for territorial sites occurs. The choice of optimal territory sites is constrained by the fact that females preferentially mate with males that defend significantly smaller holes, or crevices among the rocks, probably as a means of minimizing egg predation during spawning. 3. The population of territorial males of introduced species seems to grow exponentially, depending on the availability of suitable microhabitats, and an equilibrium between them and males of the native species may be reached. Competition for optimal territory sites seems to intensify, once the carrying capacity in a particular area has been reached, and it is at this stage that some territorial males of the introduced and native species with similar microhabitat requirements, e.g., C. afra and P. zebra, or P. tropheops 'red cheek' and its sibling native species, P. tropheops 'orange chest' displace each other. However, it seems unlikely that any of the native species which were compared with the introduced species would be driven to extinction because: (a) there is a considerable interspecific territory turn-over between the introduced and native species that overlap in microhabitat requirements. (b) Even in situations where some of the native species occur in microhabitats that are not of their preference, they occupy patches of suitable sites and are capable of breeding. (c) It has been suggested that since introduced and native species breed throughout the year and are polygamous and have intraspecifically shared paternity, they are capable of fertilizing many gravid females of their own species. Therefore, the population of native species may not be detrimentally limited by the presence of introduced species. (d) The introduced and native Mbuna species that prefer small rocks coexist in the same microhabitats, partly by feeding at different sites with different intensity and they also feed at different heights in the water column. 4. The following studies have been recommended before any management intervention, such as culling is adopted: (i). interaction between the introduced and native species in the shallow and deep rocky habitats; (ii) space utilization and survivorship of juveniles of the introduced and native species; (iii) laboratory studies to confirm the role of different nutrient regimes on the fecundity of Mbuna; (iv) the possibility of hybridization between the introduced and native species; (v) monitoring of population growth and distribution of the introduced species around Thumbi West Island should continue in order to detect their long-term effects on the native species.
- Full Text:
- Date Issued: 1997
- Authors: Munthali, Simon Muchina
- Date: 1997
- Subjects: Cichlids -- Nyasa, Lake
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5266 , http://hdl.handle.net/10962/d1005110
- Description: More than twenty years ago, over twenty species of the rock-dwelling cichlid species (Mbuna) were translocated from the northern Lake Malawi, where they are endemic, to Thumbi West Island, Lake Malawi National Park, in the southern part of Lake Malawi. Among these species, Cynotilapia afra, Pseudotropheus callainos and Pseudotropheus tropheops 'red cheek' are strongly territorial, and have increased substantially in number and are widely distributed, particularly in the three to seven metre depth band of the rocky habitats at the Island of Thumbi West. It is feared that the increase in population density of translocated species (hereafter referred to as introduced species) may be at the expense of ecologically equivalent native species which could be eliminated. In this thesis the following key hypotheses have been tested: (i) that the introduced species having originated from a region of Lake Malawi which is generally poor in nutrients and introduced in an area which is richer in nutrients, would cope better than the native species during periods of nutrient scarcity which occur frequently, often seasonally in oligotrophic lakes, such as Lake Malawi; (ii) that the introduced species are fitter than their ecologically equivalent native species in the acquisition of territorial space in which they breed, feed and seek shelter, and (iii) that introduced and native species coexist by utilizing different microhabitats. Results show that: 1. the introduced species, P. callainos and P. tropheops 'red cheek' may have responded positively to enhanced nutrient availability, as they were found to have better condition factors and fecundity indices at Thumbi West Island than at sites of their origin, in the northern lake Malawi. Cynotilapia afra, P. callainos and P. tropheops 'red cheek' also maximise their life-span fecundity by starting to reproduce at relatively smaller size than the native species with which they overlap in microhabitat requirements. Similarly, their breeding peaks precede the breeding peaks of the native species with which they overlap in microhabitat requirements. Consequently, due to priority residence effects, the offspring of introduced species may have a competitive edge in the use of essential resources, e.g., refuge over the offspring of the native species whose peak-recruitment occurs later in the year. 2. There is an overlap between the introduced and native species in their microhabitat requirements. Consequently, interference competition between them for territorial sites occurs. The choice of optimal territory sites is constrained by the fact that females preferentially mate with males that defend significantly smaller holes, or crevices among the rocks, probably as a means of minimizing egg predation during spawning. 3. The population of territorial males of introduced species seems to grow exponentially, depending on the availability of suitable microhabitats, and an equilibrium between them and males of the native species may be reached. Competition for optimal territory sites seems to intensify, once the carrying capacity in a particular area has been reached, and it is at this stage that some territorial males of the introduced and native species with similar microhabitat requirements, e.g., C. afra and P. zebra, or P. tropheops 'red cheek' and its sibling native species, P. tropheops 'orange chest' displace each other. However, it seems unlikely that any of the native species which were compared with the introduced species would be driven to extinction because: (a) there is a considerable interspecific territory turn-over between the introduced and native species that overlap in microhabitat requirements. (b) Even in situations where some of the native species occur in microhabitats that are not of their preference, they occupy patches of suitable sites and are capable of breeding. (c) It has been suggested that since introduced and native species breed throughout the year and are polygamous and have intraspecifically shared paternity, they are capable of fertilizing many gravid females of their own species. Therefore, the population of native species may not be detrimentally limited by the presence of introduced species. (d) The introduced and native Mbuna species that prefer small rocks coexist in the same microhabitats, partly by feeding at different sites with different intensity and they also feed at different heights in the water column. 4. The following studies have been recommended before any management intervention, such as culling is adopted: (i). interaction between the introduced and native species in the shallow and deep rocky habitats; (ii) space utilization and survivorship of juveniles of the introduced and native species; (iii) laboratory studies to confirm the role of different nutrient regimes on the fecundity of Mbuna; (iv) the possibility of hybridization between the introduced and native species; (v) monitoring of population growth and distribution of the introduced species around Thumbi West Island should continue in order to detect their long-term effects on the native species.
- Full Text:
- Date Issued: 1997
Generalisations of filters and uniform spaces
- Authors: Muraleetharan, Murugiah
- Date: 1997
- Subjects: Filters (Mathematics) , Uniform spaces
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5409 , http://hdl.handle.net/10962/d1005223 , Filters (Mathematics) , Uniform spaces
- Description: The notion of a filter F ∈ 2²x has been extended to that of a : prefilter: ƒ ∈ 1²x, generalised filter ƒ ∈ 2²x x and fuzzy filter ᵩ ∈ 1¹x. A uniformity is a filter with some other conditions and the notion of a uniformity D ∈ 2²xxx has been extended to that of a : fuzzy uniformity d ∈ 1²xxx , generalised uniformity ∈ 1²xxx and super uniformity b ∈ 1¹x. We establish categorical embeddings from the category of uniform spaces into the categories of fuzzy uniform spaces, generalised uniform spaces and super uniform spaces and also categorical embeddings into the category of super uniform spaces from the categories of fuzzy uniform spaces and generalised uniform spaces.
- Full Text:
- Date Issued: 1997
- Authors: Muraleetharan, Murugiah
- Date: 1997
- Subjects: Filters (Mathematics) , Uniform spaces
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5409 , http://hdl.handle.net/10962/d1005223 , Filters (Mathematics) , Uniform spaces
- Description: The notion of a filter F ∈ 2²x has been extended to that of a : prefilter: ƒ ∈ 1²x, generalised filter ƒ ∈ 2²x x and fuzzy filter ᵩ ∈ 1¹x. A uniformity is a filter with some other conditions and the notion of a uniformity D ∈ 2²xxx has been extended to that of a : fuzzy uniformity d ∈ 1²xxx , generalised uniformity ∈ 1²xxx and super uniformity b ∈ 1¹x. We establish categorical embeddings from the category of uniform spaces into the categories of fuzzy uniform spaces, generalised uniform spaces and super uniform spaces and also categorical embeddings into the category of super uniform spaces from the categories of fuzzy uniform spaces and generalised uniform spaces.
- Full Text:
- Date Issued: 1997
Guidelines for assessing single borehole yields in secondary aquifers
- Authors: Murray, Eric Charles
- Date: 1997
- Subjects: Aquifers -- Measurement
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6026 , http://hdl.handle.net/10962/d1005512
- Description: The motivation for this research project arose from the realisation that many South African rural water supply schemes fail due to the over abstraction of groundwater from single boreholes. The main reason for this mis-management of groundwater is a result of inappropriate borehole yield recommendation methods. This research project set out to review existing borehole yield assessment methods and establish new methods which take the shortcomings of existing methods into account. The study is concerned with borehole yield assessment methods applicable to secondary aquifers, since these aquifers are by far the most common in South Africa. The yield assessment methods have been grouped into those that are based on aquifer yield analyses, and on the analysis of single borehole test pump data. In order to assess which methods give suitable yield recommendations, it was necessary to compare the yields obtained using the various methods, with established yields from production boreholes. The focus of the aquifer yield component of the study, was to develop a method for estimating the proportion of recharge that can be abstracted from a single borehole located in a relatively small aquifer. The method was developed by computer simulations of aquifers with different hydraulic properties, and by establishing a formula which describes the relationship between recharge and the abstractable proportion of recharge. Under specific hydrogeological conditions, the recharge based method proved to be reliable in relation to established yields from production boreholes. Of the borehole yield assessment methods based on the analysis of test pump data, none of the existing methods proved to be reliable. However, the yields obtained using the two newly developed methods compared favourably to the established yield of existing production boreholes. Both of these methods are based on the application of the Cooper-Jacob approximation of the Theis equation. This study reviews existing methods and presents newly developed methods for recommending borehole abstraction rates in secondary aquifers. While existing borehole yield assessment methods were found to be unreliable, some of the newly developed methods, if correctly applied, give acceptable yield recommendations.
- Full Text:
- Date Issued: 1997
- Authors: Murray, Eric Charles
- Date: 1997
- Subjects: Aquifers -- Measurement
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6026 , http://hdl.handle.net/10962/d1005512
- Description: The motivation for this research project arose from the realisation that many South African rural water supply schemes fail due to the over abstraction of groundwater from single boreholes. The main reason for this mis-management of groundwater is a result of inappropriate borehole yield recommendation methods. This research project set out to review existing borehole yield assessment methods and establish new methods which take the shortcomings of existing methods into account. The study is concerned with borehole yield assessment methods applicable to secondary aquifers, since these aquifers are by far the most common in South Africa. The yield assessment methods have been grouped into those that are based on aquifer yield analyses, and on the analysis of single borehole test pump data. In order to assess which methods give suitable yield recommendations, it was necessary to compare the yields obtained using the various methods, with established yields from production boreholes. The focus of the aquifer yield component of the study, was to develop a method for estimating the proportion of recharge that can be abstracted from a single borehole located in a relatively small aquifer. The method was developed by computer simulations of aquifers with different hydraulic properties, and by establishing a formula which describes the relationship between recharge and the abstractable proportion of recharge. Under specific hydrogeological conditions, the recharge based method proved to be reliable in relation to established yields from production boreholes. Of the borehole yield assessment methods based on the analysis of test pump data, none of the existing methods proved to be reliable. However, the yields obtained using the two newly developed methods compared favourably to the established yield of existing production boreholes. Both of these methods are based on the application of the Cooper-Jacob approximation of the Theis equation. This study reviews existing methods and presents newly developed methods for recommending borehole abstraction rates in secondary aquifers. While existing borehole yield assessment methods were found to be unreliable, some of the newly developed methods, if correctly applied, give acceptable yield recommendations.
- Full Text:
- Date Issued: 1997
Student teachers' conceptualisations of 'significant' animals
- Authors: Murtough, Neil
- Date: 1997
- Subjects: Environmental education -- South Africa Teachers -- Training of -- South Africa Human-animal relationships -- South Africa -- Folklore Zoology -- South Africa -- Folklore
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1775 , http://hdl.handle.net/10962/d1003660
- Description: Constructivist approaches to teaching and learning are a well established component of the landscape of educational research, especially in Science education. This research took as its starting point the limited amount of social constructivist research available in the field of Environmental Education and responded to calls for further research. The research was designed within an interpretive tradition, as a critically phenomenological enquiry employing two methods; single case studies and a focus group. Data collection used progressively focused interview questions to proceed through a series of individual interview stages, starting with a simple description of conceptualisations and moving to deeper analysis of influences on, and use of conceptualisations. The focus group was designed as a forum to explore the pedagogic issues connected to the 'social negotiation of learning', based on data and insights gained from earlier interview stages. The goals of the study were to record data on the conceptualisations of animals perceived as significant by a group of Tsonga speaking students, and to seek insights into the formative influences on those conceptualisations. The research question, namely what contribution can social constructivist approaches to teaching and learning make to Environmental Education? guided an interpretation of the above data in terms of a range of social constructivist theories of learning. Theories of Radical and Social Constructivism as applied in Science education, although dominant orientations for educational research in constructivist learning, were challenged and found inappropriate as a basis to inform methodologies for Environmental Education. Instead Lave's (cited in O'Loughlin, 1992) socio-cultural approach to learning was explored as the basis to create a more useful perspective on an environmental education situation. Finally it was concluded that Lave's socio-cultural approach to learning may be a useful guide to helping a teacher- elicit the full range of conceptualisations present in an environmental education situation, but is not ultimately effective if no challenge and change comes about. Consequently, a socially critical constructivist teaching and learning approach was suggested In conclusion I commented on the interpretive research methodology employed and suggested an example of a socially critical methodology that could take this investigation further.
- Full Text:
- Date Issued: 1997
- Authors: Murtough, Neil
- Date: 1997
- Subjects: Environmental education -- South Africa Teachers -- Training of -- South Africa Human-animal relationships -- South Africa -- Folklore Zoology -- South Africa -- Folklore
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1775 , http://hdl.handle.net/10962/d1003660
- Description: Constructivist approaches to teaching and learning are a well established component of the landscape of educational research, especially in Science education. This research took as its starting point the limited amount of social constructivist research available in the field of Environmental Education and responded to calls for further research. The research was designed within an interpretive tradition, as a critically phenomenological enquiry employing two methods; single case studies and a focus group. Data collection used progressively focused interview questions to proceed through a series of individual interview stages, starting with a simple description of conceptualisations and moving to deeper analysis of influences on, and use of conceptualisations. The focus group was designed as a forum to explore the pedagogic issues connected to the 'social negotiation of learning', based on data and insights gained from earlier interview stages. The goals of the study were to record data on the conceptualisations of animals perceived as significant by a group of Tsonga speaking students, and to seek insights into the formative influences on those conceptualisations. The research question, namely what contribution can social constructivist approaches to teaching and learning make to Environmental Education? guided an interpretation of the above data in terms of a range of social constructivist theories of learning. Theories of Radical and Social Constructivism as applied in Science education, although dominant orientations for educational research in constructivist learning, were challenged and found inappropriate as a basis to inform methodologies for Environmental Education. Instead Lave's (cited in O'Loughlin, 1992) socio-cultural approach to learning was explored as the basis to create a more useful perspective on an environmental education situation. Finally it was concluded that Lave's socio-cultural approach to learning may be a useful guide to helping a teacher- elicit the full range of conceptualisations present in an environmental education situation, but is not ultimately effective if no challenge and change comes about. Consequently, a socially critical constructivist teaching and learning approach was suggested In conclusion I commented on the interpretive research methodology employed and suggested an example of a socially critical methodology that could take this investigation further.
- Full Text:
- Date Issued: 1997
Research report
- NALEDI
- Authors: NALEDI
- Date: 1997
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/151396 , vital:39063
- Description: The intention of this paper is to highlight debates and issues regarding the use of guota systems in strengthening women’s leadership in the labour movement. The paper is aimed at broadening the debate from mere acceptance or rejection of the guota. Debates on the use of guotas tend to be heated and controversial and can lose sight of the central objective, which is the development of strategies for women’s empowerment. A large proportion of trade unions internationally have adopted forms of the quota system as a strong measure to deal with the ongoing under-representation of women in leadership. The quota system has also been introduced effectively in a number of parliaments all over the world, including South Africa. The countries with the highest representation of women in parliament have all had to use quotas to achieve this. The paper draws from a review of some of the international literature, as well as interviews undertaken with trade unionists and parliamentarians (see Appendix A for a list of interviewees). This paper will also highlight some examples where quota systems have been adopted, including three COSATU affiliates, namely CWIU, NEHAWU and SAMWU.
- Full Text:
- Date Issued: 1997
- Authors: NALEDI
- Date: 1997
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/151396 , vital:39063
- Description: The intention of this paper is to highlight debates and issues regarding the use of guota systems in strengthening women’s leadership in the labour movement. The paper is aimed at broadening the debate from mere acceptance or rejection of the guota. Debates on the use of guotas tend to be heated and controversial and can lose sight of the central objective, which is the development of strategies for women’s empowerment. A large proportion of trade unions internationally have adopted forms of the quota system as a strong measure to deal with the ongoing under-representation of women in leadership. The quota system has also been introduced effectively in a number of parliaments all over the world, including South Africa. The countries with the highest representation of women in parliament have all had to use quotas to achieve this. The paper draws from a review of some of the international literature, as well as interviews undertaken with trade unionists and parliamentarians (see Appendix A for a list of interviewees). This paper will also highlight some examples where quota systems have been adopted, including three COSATU affiliates, namely CWIU, NEHAWU and SAMWU.
- Full Text:
- Date Issued: 1997
Policy Memo - Engineering hours of work
- NALEDI
- Authors: NALEDI
- Date: 1997
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/151200 , vital:39038
- Description: The National Union of Metal Workers of South Africa (Numsa). following Cosatu, has since its foundation argued for a 40 hour week and a ban on overtime to increase employment. The goal of a shorter working week should not. however, limit itself to employment. Metal workers work long, hard hours, an average 49 hour week in 1995. (ILO.1996:334) Shift workers often work longer, with serious health and safety risks, including shorter lives. A poor and inefficient transport system cuts at least another 5 to 10 hours a week from the time urban africans spend away from home, community and leisure. (CSS. 1995)1 Workers too must have the right to a healthy work environment and proper access to leisure time and family. The organisation of working time is also important, impacting on the ability of workers to effectively access education and training.
- Full Text:
- Date Issued: 1997
- Authors: NALEDI
- Date: 1997
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/151200 , vital:39038
- Description: The National Union of Metal Workers of South Africa (Numsa). following Cosatu, has since its foundation argued for a 40 hour week and a ban on overtime to increase employment. The goal of a shorter working week should not. however, limit itself to employment. Metal workers work long, hard hours, an average 49 hour week in 1995. (ILO.1996:334) Shift workers often work longer, with serious health and safety risks, including shorter lives. A poor and inefficient transport system cuts at least another 5 to 10 hours a week from the time urban africans spend away from home, community and leisure. (CSS. 1995)1 Workers too must have the right to a healthy work environment and proper access to leisure time and family. The organisation of working time is also important, impacting on the ability of workers to effectively access education and training.
- Full Text:
- Date Issued: 1997
Cytogenetic studies of Pseudobarbus and selected Barbus (Pisces: Cyprinidae) of southern Africa
- Authors: Naran, Daksha
- Date: 1997
- Subjects: Cyprinidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5252 , http://hdl.handle.net/10962/d1005095 , Cyprinidae
- Description: The aim of this study was to explore the karyology of temperate southern African barbine species in order to determine the extent and significance of polyploidy within the species. The study presents an optimised in vivo karyological protocol for the small barbines. The analysis of chromosomal data was explored using two approaches; measured (quantitative) and visual (qualitative). The karyology of 16 species of Barbus and six species of Pseudobarbus (Pisces: Cyprinidae) is reported. The study represents an almost complete (22/23 species) karyological survey of the temperate barbines. Chromosome number, arm numbers (NF) are recorded and karyotype morphology described for all species. Nucleolar organiser regions (NOR)s of 18 species have been examined by silver staining. Seven different AgNOR phenotypes occur among the species examined. Chromosome complements of the different species indicate at least three ploidy levels; diploid, tetraploid and hexaploid. Higher ploidy levels are represented in 78% (18/23) of species within the temperate fauna. This finding is remarkable, in the light of global proportions of cyprinid karyotypes, and provides an opportunity to shed further light on the evolution of polyploidy in barbine cyprinids. Results show that morphologically defined species complexes have distinct karyotypes, and most probably form cohesive phyletic clades. A phylogenetic tree was constructed using traditional morphological characters and tested against karyological data. The results suggests that similar ploidy states do not necessarily indicate close relationship between species. This supports a hypothesis of polyphyly for the African barbine cyprinids and also provides independent support for species complexes such as the "chubbyhead barb group" and the Pseudobarbus lineage. The broader implications of karyological findings are discussed within the context of African barbines and recommendations for further cytogenetic research are provided.
- Full Text:
- Date Issued: 1997
- Authors: Naran, Daksha
- Date: 1997
- Subjects: Cyprinidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5252 , http://hdl.handle.net/10962/d1005095 , Cyprinidae
- Description: The aim of this study was to explore the karyology of temperate southern African barbine species in order to determine the extent and significance of polyploidy within the species. The study presents an optimised in vivo karyological protocol for the small barbines. The analysis of chromosomal data was explored using two approaches; measured (quantitative) and visual (qualitative). The karyology of 16 species of Barbus and six species of Pseudobarbus (Pisces: Cyprinidae) is reported. The study represents an almost complete (22/23 species) karyological survey of the temperate barbines. Chromosome number, arm numbers (NF) are recorded and karyotype morphology described for all species. Nucleolar organiser regions (NOR)s of 18 species have been examined by silver staining. Seven different AgNOR phenotypes occur among the species examined. Chromosome complements of the different species indicate at least three ploidy levels; diploid, tetraploid and hexaploid. Higher ploidy levels are represented in 78% (18/23) of species within the temperate fauna. This finding is remarkable, in the light of global proportions of cyprinid karyotypes, and provides an opportunity to shed further light on the evolution of polyploidy in barbine cyprinids. Results show that morphologically defined species complexes have distinct karyotypes, and most probably form cohesive phyletic clades. A phylogenetic tree was constructed using traditional morphological characters and tested against karyological data. The results suggests that similar ploidy states do not necessarily indicate close relationship between species. This supports a hypothesis of polyphyly for the African barbine cyprinids and also provides independent support for species complexes such as the "chubbyhead barb group" and the Pseudobarbus lineage. The broader implications of karyological findings are discussed within the context of African barbines and recommendations for further cytogenetic research are provided.
- Full Text:
- Date Issued: 1997
Advice skills: a guide for NUMSA shopstewards, 1996-1999
- National Union of Metalworkers of South Africa (NUMSA)
- Authors: National Union of Metalworkers of South Africa (NUMSA)
- Date: 1997
- Language: English
- Type: book , text
- Identifier: http://hdl.handle.net/10962/68663 , vital:29303
- Description: The manual serves as a guide for shopstewards of the National Union of Metalworkers of South Africa (NUMSA), in assisting and providing union members with information pertaining to the basics of fair dismissal, the Unemployment Insurance Fund (UIF), Compensation for Occupational Injuries and Diseases Act (COIDA), tax and pension matters.
- Full Text:
- Date Issued: 1997
- Authors: National Union of Metalworkers of South Africa (NUMSA)
- Date: 1997
- Language: English
- Type: book , text
- Identifier: http://hdl.handle.net/10962/68663 , vital:29303
- Description: The manual serves as a guide for shopstewards of the National Union of Metalworkers of South Africa (NUMSA), in assisting and providing union members with information pertaining to the basics of fair dismissal, the Unemployment Insurance Fund (UIF), Compensation for Occupational Injuries and Diseases Act (COIDA), tax and pension matters.
- Full Text:
- Date Issued: 1997
Painting of three African women
- Authors: Ndaba, Godfrey
- Date: 1997 , 2022-10-11
- Subjects: Bam, Brigalia
- Language: English
- Type: painting , realia
- Identifier: http://hdl.handle.net/10948/57145 , vital:57341
- Description: Dr. Brigalia Bam was gifted a painting from the Electoral Commission of Uganda. A Catholic Nun decided to give Dr. Brigalia Bam the painting of three African women because of her love and care for women. , Dr Bam told the Catholic Nun about the sad death of an Anglican Bishop who had been murdered by Idi Amin, the former President of Uganda. Dr. Brigalia Bam also focused on the stories of women widows of Uganda. , Donated/gifted to Nelson Mandela University Archives , Forms part of: Brigalia Bam collection
- Full Text: false
- Date Issued: 1997
- Authors: Ndaba, Godfrey
- Date: 1997 , 2022-10-11
- Subjects: Bam, Brigalia
- Language: English
- Type: painting , realia
- Identifier: http://hdl.handle.net/10948/57145 , vital:57341
- Description: Dr. Brigalia Bam was gifted a painting from the Electoral Commission of Uganda. A Catholic Nun decided to give Dr. Brigalia Bam the painting of three African women because of her love and care for women. , Dr Bam told the Catholic Nun about the sad death of an Anglican Bishop who had been murdered by Idi Amin, the former President of Uganda. Dr. Brigalia Bam also focused on the stories of women widows of Uganda. , Donated/gifted to Nelson Mandela University Archives , Forms part of: Brigalia Bam collection
- Full Text: false
- Date Issued: 1997
Regional and local economic development strategies in the Eastern Cape and guidelines for future development
- Nel, E L
- Authors: Nel, E L
- Date: 1997
- Subjects: Community development -- South Africa -- Eastern Cape Case studies Community development Community development -- South Africa -- Eastern Cape Eastern Cape (South Africa) -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4848 , http://hdl.handle.net/10962/d1005524
- Description: Local Economic Development (LED) is an applied economic development strategy which seeks to address site-specific needs through locally appropriate solutions. In this thesis, the faith being accorded to the potential of LED in South Africa is critically examined. The study is based on a detailed examination of the experience of regional development and several emerging cases of LED in the Eastern Cape Province of South Africa. High levels of poverty and unemployment necessitate and justify innovative approaches to address such problems. The thesis examines the potential of LED strategies and identifies applied policy guidelines which can help address the Province's development needs. The theoretical framework of this research is based on a critical examination of international and South African literature dealing with development issues, LED and localities theory. A detailed documentary examination of early LED endeavours and the experience of regional development in the present century was undertaken. Results suggest that LED is not a new concept and that regional development, through its political bias, achieved only limited success. Contemporary examples of LED were identified and examined through detailed site-specific investigations. This was carried out through the use of semistructured interviews supplemented by participatory rural appraisal and questionnaire surveys which served as a means to triangulate the results. The research findings indicate that regional development, as applied in the study area, did not lead to the establishment of a permanent industrial base. In terms of the concept of LED, it is apparent that it has allowed for socio-political empowerment but has only improved economic conditions in the more well-endowed case-studies. In these areas, positive antecedent conditions and the key role played by community supportive nongovernmental organizations is apparent. Despite the limited degree of success which many initiatives attain, the thesis regards LED as a development alternative for areas which are unlikely to draw in external investment. Some of the key contributions of the thesis include the advancement of a refined typology of LED, the development of a research schedule to investigate and assess LED initiatives and the postulation of appropriate development guidelines and theoretical constructs.
- Full Text:
- Date Issued: 1997
- Authors: Nel, E L
- Date: 1997
- Subjects: Community development -- South Africa -- Eastern Cape Case studies Community development Community development -- South Africa -- Eastern Cape Eastern Cape (South Africa) -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4848 , http://hdl.handle.net/10962/d1005524
- Description: Local Economic Development (LED) is an applied economic development strategy which seeks to address site-specific needs through locally appropriate solutions. In this thesis, the faith being accorded to the potential of LED in South Africa is critically examined. The study is based on a detailed examination of the experience of regional development and several emerging cases of LED in the Eastern Cape Province of South Africa. High levels of poverty and unemployment necessitate and justify innovative approaches to address such problems. The thesis examines the potential of LED strategies and identifies applied policy guidelines which can help address the Province's development needs. The theoretical framework of this research is based on a critical examination of international and South African literature dealing with development issues, LED and localities theory. A detailed documentary examination of early LED endeavours and the experience of regional development in the present century was undertaken. Results suggest that LED is not a new concept and that regional development, through its political bias, achieved only limited success. Contemporary examples of LED were identified and examined through detailed site-specific investigations. This was carried out through the use of semistructured interviews supplemented by participatory rural appraisal and questionnaire surveys which served as a means to triangulate the results. The research findings indicate that regional development, as applied in the study area, did not lead to the establishment of a permanent industrial base. In terms of the concept of LED, it is apparent that it has allowed for socio-political empowerment but has only improved economic conditions in the more well-endowed case-studies. In these areas, positive antecedent conditions and the key role played by community supportive nongovernmental organizations is apparent. Despite the limited degree of success which many initiatives attain, the thesis regards LED as a development alternative for areas which are unlikely to draw in external investment. Some of the key contributions of the thesis include the advancement of a refined typology of LED, the development of a research schedule to investigate and assess LED initiatives and the postulation of appropriate development guidelines and theoretical constructs.
- Full Text:
- Date Issued: 1997
Solid state thermal decomposition of amide complexes of nickel(II) chloride
- Nelwamondo, Aubrey Ndifelani
- Authors: Nelwamondo, Aubrey Ndifelani
- Date: 1997
- Subjects: Decomposition (Chemistry) Materials -- Thermal properties Amides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4345 , http://hdl.handle.net/10962/d1005008
- Description: The thermal decompositions of a series of amide complexes of nickel(II) chloride have been studied. Thermochemical, kinetic, structure and solid-state stability correlations have been investigated. Complexes containing homologous amide ligands (L) of the form NiLCℓ₂, Ni₃L₂Cℓ₆, Ni₃LCℓ₆, NiL₂Cℓ₂(2H₂0) and ML₂Cℓ₂ (where M = Ni(II), Co(II) or Cu(II)) have been prepared. Chemical analysis, spectral and thermogravimetric measurements were used to characterize the complexes and their decomposition stoichiometries. Three sets of reactions were identified as yielding stable products in a single step: (i) NiLCℓ₂ (s) → NiCℓ₂ (s) + L (g) (ii) Ni₃LCℓ₆ (s) → 3NiCℓ₂ (s) + 2L (g) (iii) Ni₃LCℓ₆ (s) → 3NiCℓ₂ (s) + L (g) Characterization of the processes in the ML₂Cℓ₂ and NiL₂Cℓ₂(2H₂0) complexes was not straightforward. Reaction enthalpies (ΔH) were determined using DSC. The orders of the reaction onset temperatures (Tc), peak temperatures (Tmax) and ΔHL values for the NiCℓ₂ system were: N-methylacetamide < acetamide < N-methylformamide, suggesting the importance of steric hindrance of the methyl-substituent groups in the amide skeleton. In the Ni₃LCℓ₆, NiL₂Cℓ₂(2H₂0) and ML₂Cℓ₂ systems no simple orders could be deduced. The Te and Tmax sequences obtained from analogous metal(II) chloride complexes indicated that the copper(II) complexes were the least stable. The kinetics of the loss of L from NiLCℓ₂ complexes were investigated using isothermal TG, non-isothermal TG and DSC measurements. The contracting geometry models described the course of the decompositions in the most satisfactory manner. Apparent activation energies ( Ea) were estimated from Arrhenius plots of rate coefficients from: (i) an approximate zero-order relationship, (ii) the contracting-area (R2) and contracting-volume (R3) equations, (iii) a new empirical (B2) expression, (iv) the half-life ( 1/t₀.₅) and (v) the characteristic feature of the rate-time curve ( 1/tmax/2 ). The non-dependence of Ea on the rate equation used supports the reliability of the kinetic parameters. Non-isothermal experiments were analyzed by the Coats-Redfern, the modified BorchardtDaniels and the Kissinger methods. Arrhenius parameters were in keeping with results from the isothermal kinetic measurements. The values of Ea obtained for the NiLCℓ₂ system increased with an increase in basicity of the amide ligands. No straightforward correlation was found between Ea and Te, Tmax, ΔHL or spectral properties.
- Full Text:
- Date Issued: 1997
- Authors: Nelwamondo, Aubrey Ndifelani
- Date: 1997
- Subjects: Decomposition (Chemistry) Materials -- Thermal properties Amides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4345 , http://hdl.handle.net/10962/d1005008
- Description: The thermal decompositions of a series of amide complexes of nickel(II) chloride have been studied. Thermochemical, kinetic, structure and solid-state stability correlations have been investigated. Complexes containing homologous amide ligands (L) of the form NiLCℓ₂, Ni₃L₂Cℓ₆, Ni₃LCℓ₆, NiL₂Cℓ₂(2H₂0) and ML₂Cℓ₂ (where M = Ni(II), Co(II) or Cu(II)) have been prepared. Chemical analysis, spectral and thermogravimetric measurements were used to characterize the complexes and their decomposition stoichiometries. Three sets of reactions were identified as yielding stable products in a single step: (i) NiLCℓ₂ (s) → NiCℓ₂ (s) + L (g) (ii) Ni₃LCℓ₆ (s) → 3NiCℓ₂ (s) + 2L (g) (iii) Ni₃LCℓ₆ (s) → 3NiCℓ₂ (s) + L (g) Characterization of the processes in the ML₂Cℓ₂ and NiL₂Cℓ₂(2H₂0) complexes was not straightforward. Reaction enthalpies (ΔH) were determined using DSC. The orders of the reaction onset temperatures (Tc), peak temperatures (Tmax) and ΔHL values for the NiCℓ₂ system were: N-methylacetamide < acetamide < N-methylformamide, suggesting the importance of steric hindrance of the methyl-substituent groups in the amide skeleton. In the Ni₃LCℓ₆, NiL₂Cℓ₂(2H₂0) and ML₂Cℓ₂ systems no simple orders could be deduced. The Te and Tmax sequences obtained from analogous metal(II) chloride complexes indicated that the copper(II) complexes were the least stable. The kinetics of the loss of L from NiLCℓ₂ complexes were investigated using isothermal TG, non-isothermal TG and DSC measurements. The contracting geometry models described the course of the decompositions in the most satisfactory manner. Apparent activation energies ( Ea) were estimated from Arrhenius plots of rate coefficients from: (i) an approximate zero-order relationship, (ii) the contracting-area (R2) and contracting-volume (R3) equations, (iii) a new empirical (B2) expression, (iv) the half-life ( 1/t₀.₅) and (v) the characteristic feature of the rate-time curve ( 1/tmax/2 ). The non-dependence of Ea on the rate equation used supports the reliability of the kinetic parameters. Non-isothermal experiments were analyzed by the Coats-Redfern, the modified BorchardtDaniels and the Kissinger methods. Arrhenius parameters were in keeping with results from the isothermal kinetic measurements. The values of Ea obtained for the NiLCℓ₂ system increased with an increase in basicity of the amide ligands. No straightforward correlation was found between Ea and Te, Tmax, ΔHL or spectral properties.
- Full Text:
- Date Issued: 1997
Photosensitization reactions of neodymium, dysprosium and lutetium diphthalocyanine
- Nensala, Ngudiankama, Nyokong, Tebello
- Authors: Nensala, Ngudiankama , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:57084 , xlink:href="https://doi.org/10.1016/S0277-5387(97)00045-4"
- Description: Photolysis, using a visible radiation, of diphthalocyanine complexes of NdIII, DyIII and LuIII ([Pc(−2)NdIIIPc(−2)]−, [Pc(−2)DyIIIPc(−2)]− and [Pc(−2)LuIIIPc(−2)]−, respectively) in the presence of pentachlorophenol (PCP) or SO2 results in the one-electron oxidation of the diphthalocyanine species to Pc(−1)NdIIIPc(−2), Pc(−1)DyIIIPc(−2) and Pc(−2)LuIIIPc(−2), respectively. The PCP is reductively dechlorinated to tetra- and trichlorophenols. The quantum yields for the photosensitization reactions are of the order 10−4.
- Full Text:
- Date Issued: 1997
- Authors: Nensala, Ngudiankama , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:57084 , xlink:href="https://doi.org/10.1016/S0277-5387(97)00045-4"
- Description: Photolysis, using a visible radiation, of diphthalocyanine complexes of NdIII, DyIII and LuIII ([Pc(−2)NdIIIPc(−2)]−, [Pc(−2)DyIIIPc(−2)]− and [Pc(−2)LuIIIPc(−2)]−, respectively) in the presence of pentachlorophenol (PCP) or SO2 results in the one-electron oxidation of the diphthalocyanine species to Pc(−1)NdIIIPc(−2), Pc(−1)DyIIIPc(−2) and Pc(−2)LuIIIPc(−2), respectively. The PCP is reductively dechlorinated to tetra- and trichlorophenols. The quantum yields for the photosensitization reactions are of the order 10−4.
- Full Text:
- Date Issued: 1997
A comparative study of the Grey-headed Sparrow (Passer griseus L) and the House Sparrow (Passer domesticus L) in Malawi
- Authors: Nhlane, Martin Edwin Darwin
- Date: 1997
- Subjects: English sparrow Sparrows
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5654 , http://hdl.handle.net/10962/d1005337
- Description: The House Sparrow Passer domesticus, an introduced species, and the Grey-headed Sparrow Passer griseus, an indigenous species, are sympatric in Malawi. Their distribution in the country and any possible interactions were studied, principally in southern Malawi. A morphological analysis of museum specimens confirmed that grey-headed sparrows in Malawi belong to the Northern Grey-headed Sparrow Passer griseus as distinct from the Southern Grey-headed Sparrow Passer diffusus. This species was widely distributed in the, country in association with human dwellings, both in rural areas as well as urban centres. In the northern region Greyheaded Sparrows were more abundant in the urban centres than rural areas, but in the central and southern regions numbers in the rural and urban areas were more or less the same. In Blantyre City, where they are in sympatry with the House Sparrow, they were found in the low density and industrial areas and were absent from the high density areas. The House Sparrow, arrived in Malawi in 1967 at Chileka in the southern region. Since then it has spread northwards, moving from the southern to the central and northern regions. House Sparrow numbers were found to be progressively larger in the southern region and lowest in the northern region. House Sparrows were found at sites where food was readily available, as in the immediate vicinity of houses. In the central and northern regions they were restricted mainly to urban areas. In the southern region, they occur both in rural and urban areas, probably as a reflection of the larger period of colonization in the south. In the northern region their movement has apparently been restricted by geographical barriers. In Blantyre City Grey-headed Sparrows preferred areas where tree density was high and house density was low, while House Sparrows preferred areas where house density was high and tree density was low. There was a positive correlation between Greyheaded Sparrow numbers and tree density and a negative correlation with house density. House Sparrow abundance was negatively correlated with tree density and positively correlated with house density. Grey-headed Sparrows bred in the rainy season, whereas House Sparrows bred throughout the year. There were differences in nest site selection: Grey-headed Sparrows used artificial structures such as fencing poles, and wooden telephone or electricity poles. The House Sparrow used mostly buildings and nested in crevices, holes in walls and between the walls and rafters. Nest height also differed- Grey-headed Sparrows nested at heights ranging from 1 - 8 m while House Sparrow nests were at heights of 1 - 5 m. Moult data suggests that although the House Sparrows breed throughout the year, they moult at a particular time of the year when breeding is less common. Grey-headed Sparrows were found to moult mainly from May to September in southern Africa and from June to September in central Africa. In both cases the breeding season extends over a similar period from about October to April/May of the following year. Peak moult periods differed between the House Sparrows and Grey-headed Sparrows. House Sparrows moulted mainly in the first half of the year, and Greyheaded Sparrows in the second six months. The clutch sizes of the two species were similar (mean 3.9 eggs for the House Sparrow and 3.4 for the Grey-headed Sparrow). The clutch size of the House Sparrow varied seasonally and was larger from November to May. The average incubation period for the House Sparrow was 11.5 days and the fledging period 15.4 days. The Grey-headed Sparrow fledging period was 14.7 days. Chick mortality of the House Sparrow at Chikunda farm was attributed to starvation resulting from brood reduction, abandonment, predation, low birth weight, accidental deaths and parasitism by fly larvae. Both Grey-headed and House Sparrows fed their young on insect food. Male House Sparrows fed actively initially, but their contribution declined from about day five onwards. In the Grey-headed Sparrow, both parents fed their young equally throughout the nestling period. House Sparrows fed on the ground near houses; Grey-headed Sparrows fed both on the ground away from houses and in tree canopies. The Grey-headed Sparrow walked as it fed on the ground as opposed to the House sparrow which hopped. Grey-headed Sparrows fed mainly as pairs and singletons while House Sparrows fed as family groups. Larger feeding groups of Grey-headed Sparrows were seen in the northern region at areas where food was plentiful. Where the two sparrows were seen feeding together, there was no direct competition for food. Where individual distance was violated; male House Sparrows displaced Grey-headed Sparrows which landed too close to them. Overall it appears that the distribution of the two species is determined more by their responses to habitat conditions than by interspecific interactions.
- Full Text:
- Date Issued: 1997
- Authors: Nhlane, Martin Edwin Darwin
- Date: 1997
- Subjects: English sparrow Sparrows
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5654 , http://hdl.handle.net/10962/d1005337
- Description: The House Sparrow Passer domesticus, an introduced species, and the Grey-headed Sparrow Passer griseus, an indigenous species, are sympatric in Malawi. Their distribution in the country and any possible interactions were studied, principally in southern Malawi. A morphological analysis of museum specimens confirmed that grey-headed sparrows in Malawi belong to the Northern Grey-headed Sparrow Passer griseus as distinct from the Southern Grey-headed Sparrow Passer diffusus. This species was widely distributed in the, country in association with human dwellings, both in rural areas as well as urban centres. In the northern region Greyheaded Sparrows were more abundant in the urban centres than rural areas, but in the central and southern regions numbers in the rural and urban areas were more or less the same. In Blantyre City, where they are in sympatry with the House Sparrow, they were found in the low density and industrial areas and were absent from the high density areas. The House Sparrow, arrived in Malawi in 1967 at Chileka in the southern region. Since then it has spread northwards, moving from the southern to the central and northern regions. House Sparrow numbers were found to be progressively larger in the southern region and lowest in the northern region. House Sparrows were found at sites where food was readily available, as in the immediate vicinity of houses. In the central and northern regions they were restricted mainly to urban areas. In the southern region, they occur both in rural and urban areas, probably as a reflection of the larger period of colonization in the south. In the northern region their movement has apparently been restricted by geographical barriers. In Blantyre City Grey-headed Sparrows preferred areas where tree density was high and house density was low, while House Sparrows preferred areas where house density was high and tree density was low. There was a positive correlation between Greyheaded Sparrow numbers and tree density and a negative correlation with house density. House Sparrow abundance was negatively correlated with tree density and positively correlated with house density. Grey-headed Sparrows bred in the rainy season, whereas House Sparrows bred throughout the year. There were differences in nest site selection: Grey-headed Sparrows used artificial structures such as fencing poles, and wooden telephone or electricity poles. The House Sparrow used mostly buildings and nested in crevices, holes in walls and between the walls and rafters. Nest height also differed- Grey-headed Sparrows nested at heights ranging from 1 - 8 m while House Sparrow nests were at heights of 1 - 5 m. Moult data suggests that although the House Sparrows breed throughout the year, they moult at a particular time of the year when breeding is less common. Grey-headed Sparrows were found to moult mainly from May to September in southern Africa and from June to September in central Africa. In both cases the breeding season extends over a similar period from about October to April/May of the following year. Peak moult periods differed between the House Sparrows and Grey-headed Sparrows. House Sparrows moulted mainly in the first half of the year, and Greyheaded Sparrows in the second six months. The clutch sizes of the two species were similar (mean 3.9 eggs for the House Sparrow and 3.4 for the Grey-headed Sparrow). The clutch size of the House Sparrow varied seasonally and was larger from November to May. The average incubation period for the House Sparrow was 11.5 days and the fledging period 15.4 days. The Grey-headed Sparrow fledging period was 14.7 days. Chick mortality of the House Sparrow at Chikunda farm was attributed to starvation resulting from brood reduction, abandonment, predation, low birth weight, accidental deaths and parasitism by fly larvae. Both Grey-headed and House Sparrows fed their young on insect food. Male House Sparrows fed actively initially, but their contribution declined from about day five onwards. In the Grey-headed Sparrow, both parents fed their young equally throughout the nestling period. House Sparrows fed on the ground near houses; Grey-headed Sparrows fed both on the ground away from houses and in tree canopies. The Grey-headed Sparrow walked as it fed on the ground as opposed to the House sparrow which hopped. Grey-headed Sparrows fed mainly as pairs and singletons while House Sparrows fed as family groups. Larger feeding groups of Grey-headed Sparrows were seen in the northern region at areas where food was plentiful. Where the two sparrows were seen feeding together, there was no direct competition for food. Where individual distance was violated; male House Sparrows displaced Grey-headed Sparrows which landed too close to them. Overall it appears that the distribution of the two species is determined more by their responses to habitat conditions than by interspecific interactions.
- Full Text:
- Date Issued: 1997
Theories of international cooperation and the GATT/WTO regime: beyond the dichotomy of rational and cognitive approaches
- Authors: Nischalke, Tobias Ingo
- Date: 1997
- Subjects: General Agreement on Tariffs and Trade (Organization) , World Trade Organization , International trade
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2817 , http://hdl.handle.net/10962/d1003027 , General Agreement on Tariffs and Trade (Organization) , World Trade Organization , International trade
- Description: This thesis aspires to assess the explanatory value of different theories of international cooperation for the case of the world trade regime of GATT/WTO and subsequently strives to reach a satisfactory interpretation of the instance of cooperation. The world trade regime embarked on a process of transformation with the signing of the Marrakech Agreements of 15th April 1994. The event marked the conclusion of the Uruguay Round and, with the establishment of the WTO, the beginning of a new era for the world trade regime. The thesis endeavours to establish the substance of the regime change from GATT to the WTO. It outlines the most significant provisions of the agreement of the Uruguay Round and, subsequently, analyses the change on the level of regime norms underlying the world trade regime. The analysis of regime norms yields insights about the essence of the regime transformation and as to what factors proved to be conducive to cooperation in the sphere of the world trade. The GATT/WTO regime with its extended scope and more sophisticated institutional structures can be regarded as a prime example of successful cooperation. However, the prospects for cooperation between states in an anarchic environment without central authority for enforcement are the subject of a remarkably intense scholarly debate. Therefore it is worthwhile to examine which theoretical framework proves to be most adept at elucidating the circumstances of this instance of cooperation. This thesis applies different theories of international cooperation to the case of the GATT/WTO regime. While a large array of rational theories attempts to explain cooperation from a perspective which focuses on interests and capabilities, a different strand of theories, that of cognitive approaches, emphasizes the paramountcy of ideas and beliefs as variables which explain cooperation. They endogenize the process of interest formation. This thesis seeks to synthesise the strong points of rational and cognitive approaches and thus to reconcile the divergent schools of thought. Its further purpose is to set out factors which are conducive to cooperation.
- Full Text:
- Date Issued: 1997
- Authors: Nischalke, Tobias Ingo
- Date: 1997
- Subjects: General Agreement on Tariffs and Trade (Organization) , World Trade Organization , International trade
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2817 , http://hdl.handle.net/10962/d1003027 , General Agreement on Tariffs and Trade (Organization) , World Trade Organization , International trade
- Description: This thesis aspires to assess the explanatory value of different theories of international cooperation for the case of the world trade regime of GATT/WTO and subsequently strives to reach a satisfactory interpretation of the instance of cooperation. The world trade regime embarked on a process of transformation with the signing of the Marrakech Agreements of 15th April 1994. The event marked the conclusion of the Uruguay Round and, with the establishment of the WTO, the beginning of a new era for the world trade regime. The thesis endeavours to establish the substance of the regime change from GATT to the WTO. It outlines the most significant provisions of the agreement of the Uruguay Round and, subsequently, analyses the change on the level of regime norms underlying the world trade regime. The analysis of regime norms yields insights about the essence of the regime transformation and as to what factors proved to be conducive to cooperation in the sphere of the world trade. The GATT/WTO regime with its extended scope and more sophisticated institutional structures can be regarded as a prime example of successful cooperation. However, the prospects for cooperation between states in an anarchic environment without central authority for enforcement are the subject of a remarkably intense scholarly debate. Therefore it is worthwhile to examine which theoretical framework proves to be most adept at elucidating the circumstances of this instance of cooperation. This thesis applies different theories of international cooperation to the case of the GATT/WTO regime. While a large array of rational theories attempts to explain cooperation from a perspective which focuses on interests and capabilities, a different strand of theories, that of cognitive approaches, emphasizes the paramountcy of ideas and beliefs as variables which explain cooperation. They endogenize the process of interest formation. This thesis seeks to synthesise the strong points of rational and cognitive approaches and thus to reconcile the divergent schools of thought. Its further purpose is to set out factors which are conducive to cooperation.
- Full Text:
- Date Issued: 1997
Detached harmonies : a study in/on developing social processes of environmental education in eastern southern Africa
- Authors: O'Donoghue, Rob
- Date: 1997
- Subjects: Environmental education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1939 , http://hdl.handle.net/10962/d1007726
- Description: Long-term social processes are explored to examine the shaping of environmental education in eastern southern Africa. The study opens with early Nguni social figurations when 'to conserve was to hunt.' It then examines colonial conservation on the frontiers of imperial expansion and developing struggles for and against wildlife preservation. These processes shaped an inversion of earlier harmonies as declining wildlife was protected in island sanctuaries of natural wilderness and 'to conserve was not to hunt.' Inside protected areas, conservation management struggles shaped new harmonies of interdependence in nature, enabling better steering choices in developing conservation science institutions. Here more reality congruent knowledge also revealed escalating risk which was linked to a lack of awareness amongst communities of 'others' outside. Within continuing conservation struggles, education in, about and for the environment emerged as new institutional processes of social control. The study examines wilderness experience, interpretation, extension, conservancies and the development of an environmental education field centre, a teacher education programme and a school curriculum. Naming and clarifying the emergent education game for reshaping the awareness and behaviour of others is examined within a developing figuration of environmental education specialists. Particular attention is given to academic and statutory processes shaping environmental education as a field of objective principles and rational processes within modernist continuities and discontinuities into the 1990's. An environmental education field centre, an earth-love curriculum and research on reserve neighbour interaction are examined as political sociologies developing within a declining power gradient and wide ranging socio-political change. Into the present, a final window on a local case of water pollution examines shifting relational dynamics revealing how environment and development education models of process may have little resonance amidst long-term socio-historical struggles and shifting controls over surroundings, others and self. A concluding review suggests that grounded critical processes engaging somewhat blind control over surroundings may yet reshape self-control and social control amongst others. The trajectories of these clarifying struggles must remain open-ended as sedimented myth and memory is reshaped within ongoing processes of escalating risk and global intermeshing.
- Full Text:
- Date Issued: 1997
- Authors: O'Donoghue, Rob
- Date: 1997
- Subjects: Environmental education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1939 , http://hdl.handle.net/10962/d1007726
- Description: Long-term social processes are explored to examine the shaping of environmental education in eastern southern Africa. The study opens with early Nguni social figurations when 'to conserve was to hunt.' It then examines colonial conservation on the frontiers of imperial expansion and developing struggles for and against wildlife preservation. These processes shaped an inversion of earlier harmonies as declining wildlife was protected in island sanctuaries of natural wilderness and 'to conserve was not to hunt.' Inside protected areas, conservation management struggles shaped new harmonies of interdependence in nature, enabling better steering choices in developing conservation science institutions. Here more reality congruent knowledge also revealed escalating risk which was linked to a lack of awareness amongst communities of 'others' outside. Within continuing conservation struggles, education in, about and for the environment emerged as new institutional processes of social control. The study examines wilderness experience, interpretation, extension, conservancies and the development of an environmental education field centre, a teacher education programme and a school curriculum. Naming and clarifying the emergent education game for reshaping the awareness and behaviour of others is examined within a developing figuration of environmental education specialists. Particular attention is given to academic and statutory processes shaping environmental education as a field of objective principles and rational processes within modernist continuities and discontinuities into the 1990's. An environmental education field centre, an earth-love curriculum and research on reserve neighbour interaction are examined as political sociologies developing within a declining power gradient and wide ranging socio-political change. Into the present, a final window on a local case of water pollution examines shifting relational dynamics revealing how environment and development education models of process may have little resonance amidst long-term socio-historical struggles and shifting controls over surroundings, others and self. A concluding review suggests that grounded critical processes engaging somewhat blind control over surroundings may yet reshape self-control and social control amongst others. The trajectories of these clarifying struggles must remain open-ended as sedimented myth and memory is reshaped within ongoing processes of escalating risk and global intermeshing.
- Full Text:
- Date Issued: 1997
An examination of the factors underlying decision-making about selection and presentation of photographs of political conflict in South African newspapers
- Authors: O'Dowd, Catherine Frances
- Date: 1997
- Subjects: Photojournalism , Photojournalism -- South Africa , Photojournalists -- South Africa , South Africa -- Politics and government -- 1989-1994
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3478 , http://hdl.handle.net/10962/d1002933 , Photojournalism , Photojournalism -- South Africa , Photojournalists -- South Africa , South Africa -- Politics and government -- 1989-1994
- Description: What newspaper readers see of an event is detennined by what photographs are seley ted and how they are presented. This thesis attempts to deconstruct the decision-making process around selection and presentation of photographs, with the aim of detennining what factors are taken into account in that process. It is based on the hypothesis that there must be a number of factors involved in decisions about news photographs, although these factors may not necessarily be consciously acknowledged in the decision-making process. The study involves a comparison of how five case studies of incidents of political violence, which occurred between 1990 and 1994 in South Africa, were used'in lrinewspapers. The focus on images of political violence is based on the assumption that politically and visually controversial images will give rise to situations in which gatekeepers will be caned upon to question their decisions. The research is based on qualitative research interviews with the decision-makers involved in the case studies. The analysis of the decision-making procedures is based on the theory of gatekeeping. The interviews are analysed in terms of Lewin's theory offqrces, which suggests that, depending on the context, some factors will manifest themselves as positive forces working in favour of the photograph being selected or well presented, while others will take the form of negative forces. The analysis sets out to determine what factors were taken into account in the decision::making process, what detennined their relative degrees of importance and how those relative degrees of importance determined the final outcome. Following an introduction to the practical case study research, dealing with general issues such as picture policy in newspapers and decision-making procedures, each case study is dealt with in turn. After an outline of the context in which the event occurred, the kinds of pictures that were available to the newspapers are described. Then the decisions taken about which to choose and how to use them are analysed in terms of dominant themes. These are themes such as newsworthiness, gruesomeness of content and concern abo!Jt what other media were using. The analysis examines the way the news context and the decision-making context determine the relative importance of the various factors present. Finally the study looks at the conclusions that can be drawn from the five case studies. The conclusion supports the initial hypothesis in finding that these decisions can be shown to have their basis in a fairly limited set of factors. The different results, from study to study and from newspaper to newspaper within a study, are determined by the changing news context and the decisi~n-making context.
- Full Text:
- Date Issued: 1997
- Authors: O'Dowd, Catherine Frances
- Date: 1997
- Subjects: Photojournalism , Photojournalism -- South Africa , Photojournalists -- South Africa , South Africa -- Politics and government -- 1989-1994
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3478 , http://hdl.handle.net/10962/d1002933 , Photojournalism , Photojournalism -- South Africa , Photojournalists -- South Africa , South Africa -- Politics and government -- 1989-1994
- Description: What newspaper readers see of an event is detennined by what photographs are seley ted and how they are presented. This thesis attempts to deconstruct the decision-making process around selection and presentation of photographs, with the aim of detennining what factors are taken into account in that process. It is based on the hypothesis that there must be a number of factors involved in decisions about news photographs, although these factors may not necessarily be consciously acknowledged in the decision-making process. The study involves a comparison of how five case studies of incidents of political violence, which occurred between 1990 and 1994 in South Africa, were used'in lrinewspapers. The focus on images of political violence is based on the assumption that politically and visually controversial images will give rise to situations in which gatekeepers will be caned upon to question their decisions. The research is based on qualitative research interviews with the decision-makers involved in the case studies. The analysis of the decision-making procedures is based on the theory of gatekeeping. The interviews are analysed in terms of Lewin's theory offqrces, which suggests that, depending on the context, some factors will manifest themselves as positive forces working in favour of the photograph being selected or well presented, while others will take the form of negative forces. The analysis sets out to determine what factors were taken into account in the decision::making process, what detennined their relative degrees of importance and how those relative degrees of importance determined the final outcome. Following an introduction to the practical case study research, dealing with general issues such as picture policy in newspapers and decision-making procedures, each case study is dealt with in turn. After an outline of the context in which the event occurred, the kinds of pictures that were available to the newspapers are described. Then the decisions taken about which to choose and how to use them are analysed in terms of dominant themes. These are themes such as newsworthiness, gruesomeness of content and concern abo!Jt what other media were using. The analysis examines the way the news context and the decision-making context determine the relative importance of the various factors present. Finally the study looks at the conclusions that can be drawn from the five case studies. The conclusion supports the initial hypothesis in finding that these decisions can be shown to have their basis in a fairly limited set of factors. The different results, from study to study and from newspaper to newspaper within a study, are determined by the changing news context and the decisi~n-making context.
- Full Text:
- Date Issued: 1997