Pauline Smith : between worlds
- Authors: Driver, Dorothy
- Date: 1987
- Subjects: Smith, Pauline, 1883-1959
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2266 , http://hdl.handle.net/10962/d1004792
- Full Text:
- Date Issued: 1987
- Authors: Driver, Dorothy
- Date: 1987
- Subjects: Smith, Pauline, 1883-1959
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2266 , http://hdl.handle.net/10962/d1004792
- Full Text:
- Date Issued: 1987
Studies on the biology of the economic marine red alga Gelidium pristoides (Turner) Kuetzing (Gelidiales : Rhodophyta)
- Authors: Carter, Alan Robert
- Date: 1987
- Subjects: Red algae Marine algae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4240 , http://hdl.handle.net/10962/d1004774
- Description: Various aspects of the biology of the intertidal agarophyte, Gelidium pristoides, were investigated, with the aim of providing information that would assist in formulating a management policy for this economic seaweed resource. G.pristoides occurs as tufts comprising as many as 40 individual plants, representing all three conspicuous life history stages, that are linked by the intertwining of their basal creeping axes. Individual plants consist of a system of branched creeping axes, which is largely responsible for colonizing surrounding substrata, from which one or more erect flattened fronds arise. These erect fronds may reach a height of 15 cm, and are irregularly bipinnately branched. Internal vegetative anatomy is generally typical of the genus. Morphological variation in mature plants is limited to increased plant height and branch density during the summer season. A dorso-ventrally flattened creeping habit was seen during early recruitment on flat rock surfaces and limpet shells within grazer exclusion plots, which developed into typical erect plants. Although there is a close taxonomic affinity between G.pristoides and the low-growing Gelidium turf, which occurs on wave-cut platforms in the eastern Cape (both produce bispores), the turf appears to represent a genetically divergent ecotype of the typical G.pristoides habit. In the light of present observations, it is suggested that the recent inclusion of G.pristoides in the new Onikusa genus should be questioned. Reproduction in G.pristoides is typical of the genus, except for the production of bispores, instead of tetraspores, in the sporophyte generation. The smaller nuclei in the binucleate bispores, in comparison to carpospores, suggested they are the product of normal meiosis (meiospores). This was confi rmed by chromosome counts of germl i ngs deri ved from bispores (n = 13-17) and carpospores (2n = 28-33). Throughout the geographical range of the seaweed, the bisporophyte generation is dominant over the combined male and female gametophyte generati on by a ratio of about 3 : 1. This imbalance may be due to bispores. G.pristoides a greater germination success of carpospores over plants are fertile throughout the year, while at Port Alfred there is no apparent seasonality in spore release. Growth of carpospore and bispore germlings is similar under various temperature treatments in culture. Optimum temperatures for growth were from 15-23°C, which corresponds with the sea temperatures experienced within the geographical range of the species . At Port Alfred, growth (linear frond elongation) and standing crop levels were maximal during summer . Ory weight levels were significantly inversely related to both growth and ash levels. Agar contents (% of dry weight) were generally greater in summer (48% ) than in winter (30%), and were inversely correlated with thallus nitrogen levels. Agar contents of distal plant halves were higher (8-15%) than in proximal halves. Regrowth of G.pristoides to original biomass or standing crop levels after harvesting, is similar for plucking and shearing at different times of the year. Regrowth is more rapid after spring and summer harvests (2-3 months) than after winter harvests (4-5 months). During the summer season, harvesting at monthly intervals showed significantly greater total yields, and production rates (e.g . 3.13 g. dry wt. / m2 / day for plucking) than under 3-monthly intervals (1.42 g. dry wt. / m2 / day for plucking). In contrast, average yields per harvest were Significantly greater when recovery period was longer (e.g. 3 months). Quadrats that were completely denuded failed to recover after a year, while regrowth was also retarded with increased elevation on the shore. Agar contents did not differ Significantly between plucked (38%) and sheared (42%) plant material. G.pristoides is distributed from about 0 . 2-0.75 m above MLWS, with a reduction in stature and frequency corresponding to increased elevation on the shore. Frond elongation rates, germling survival and recruitment within grazer-exclusion plots, is retarded with increased elevation level. Plants transplanted above the normal vertical range of the seaweed became severely bleached and died, while plants transplanted below the normal range of the seaweed (sub littoral fringe) senesced due to overgrowth by the epiphytic encrusting coralline, Polyporolithon patena (Hook . et Harv . ) Mason . G.pristoides recrui t ment in the sublittoral fri nge was enhanced with the exclusion of grazers . However, successful recruits were displaced due to smothering by articulated corallines (e.g. Corallina sp. and Jania sp. ) . G.pristoides is largely restricted to cracks and crevices in the rock, and also occurs on a large proportion of the available shells of the limpet Patella oculus Born., and to a lesser extent, shells of the barnacle Tetraclita serrata. G.pristoides recruitment was significantly enhanced by the exclusion of grazers (using toxic antifouling paint barriers). G.pristoides recruitment within the exclusion plots was significantly greater on artificially attached limpet shells (almost 100% cover) than on rock surfaces (20-30% cover), which occurred largely within cracks and crevies in the rocky substratum. ly attached to limpet G.pristoides plants are significantly more strongand barnacle shells than to rock and epilithic encrusting corallines (Lithothamnion sp.). Removal of G.pristoides from limpet shells revealed pits of a uniform size in the surface of the shells, into which the rhizoidal attachment organs of the seaweed penetrate. It is concluded that the horizontal distribution of G.pristoides is largely controlled by grazers (and "escapes" from grazing) and resistance to dislodgement by wave action. Based on present results, and considering some of the socio-economic factors associated with the Gelidium industry in South Africa, suggestions are made concerning the management and long-term maintenance of G.pristoides resources in the eastern Cape.
- Full Text:
- Date Issued: 1987
- Authors: Carter, Alan Robert
- Date: 1987
- Subjects: Red algae Marine algae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4240 , http://hdl.handle.net/10962/d1004774
- Description: Various aspects of the biology of the intertidal agarophyte, Gelidium pristoides, were investigated, with the aim of providing information that would assist in formulating a management policy for this economic seaweed resource. G.pristoides occurs as tufts comprising as many as 40 individual plants, representing all three conspicuous life history stages, that are linked by the intertwining of their basal creeping axes. Individual plants consist of a system of branched creeping axes, which is largely responsible for colonizing surrounding substrata, from which one or more erect flattened fronds arise. These erect fronds may reach a height of 15 cm, and are irregularly bipinnately branched. Internal vegetative anatomy is generally typical of the genus. Morphological variation in mature plants is limited to increased plant height and branch density during the summer season. A dorso-ventrally flattened creeping habit was seen during early recruitment on flat rock surfaces and limpet shells within grazer exclusion plots, which developed into typical erect plants. Although there is a close taxonomic affinity between G.pristoides and the low-growing Gelidium turf, which occurs on wave-cut platforms in the eastern Cape (both produce bispores), the turf appears to represent a genetically divergent ecotype of the typical G.pristoides habit. In the light of present observations, it is suggested that the recent inclusion of G.pristoides in the new Onikusa genus should be questioned. Reproduction in G.pristoides is typical of the genus, except for the production of bispores, instead of tetraspores, in the sporophyte generation. The smaller nuclei in the binucleate bispores, in comparison to carpospores, suggested they are the product of normal meiosis (meiospores). This was confi rmed by chromosome counts of germl i ngs deri ved from bispores (n = 13-17) and carpospores (2n = 28-33). Throughout the geographical range of the seaweed, the bisporophyte generation is dominant over the combined male and female gametophyte generati on by a ratio of about 3 : 1. This imbalance may be due to bispores. G.pristoides a greater germination success of carpospores over plants are fertile throughout the year, while at Port Alfred there is no apparent seasonality in spore release. Growth of carpospore and bispore germlings is similar under various temperature treatments in culture. Optimum temperatures for growth were from 15-23°C, which corresponds with the sea temperatures experienced within the geographical range of the species . At Port Alfred, growth (linear frond elongation) and standing crop levels were maximal during summer . Ory weight levels were significantly inversely related to both growth and ash levels. Agar contents (% of dry weight) were generally greater in summer (48% ) than in winter (30%), and were inversely correlated with thallus nitrogen levels. Agar contents of distal plant halves were higher (8-15%) than in proximal halves. Regrowth of G.pristoides to original biomass or standing crop levels after harvesting, is similar for plucking and shearing at different times of the year. Regrowth is more rapid after spring and summer harvests (2-3 months) than after winter harvests (4-5 months). During the summer season, harvesting at monthly intervals showed significantly greater total yields, and production rates (e.g . 3.13 g. dry wt. / m2 / day for plucking) than under 3-monthly intervals (1.42 g. dry wt. / m2 / day for plucking). In contrast, average yields per harvest were Significantly greater when recovery period was longer (e.g. 3 months). Quadrats that were completely denuded failed to recover after a year, while regrowth was also retarded with increased elevation on the shore. Agar contents did not differ Significantly between plucked (38%) and sheared (42%) plant material. G.pristoides is distributed from about 0 . 2-0.75 m above MLWS, with a reduction in stature and frequency corresponding to increased elevation on the shore. Frond elongation rates, germling survival and recruitment within grazer-exclusion plots, is retarded with increased elevation level. Plants transplanted above the normal vertical range of the seaweed became severely bleached and died, while plants transplanted below the normal range of the seaweed (sub littoral fringe) senesced due to overgrowth by the epiphytic encrusting coralline, Polyporolithon patena (Hook . et Harv . ) Mason . G.pristoides recrui t ment in the sublittoral fri nge was enhanced with the exclusion of grazers . However, successful recruits were displaced due to smothering by articulated corallines (e.g. Corallina sp. and Jania sp. ) . G.pristoides is largely restricted to cracks and crevices in the rock, and also occurs on a large proportion of the available shells of the limpet Patella oculus Born., and to a lesser extent, shells of the barnacle Tetraclita serrata. G.pristoides recruitment was significantly enhanced by the exclusion of grazers (using toxic antifouling paint barriers). G.pristoides recruitment within the exclusion plots was significantly greater on artificially attached limpet shells (almost 100% cover) than on rock surfaces (20-30% cover), which occurred largely within cracks and crevies in the rocky substratum. ly attached to limpet G.pristoides plants are significantly more strongand barnacle shells than to rock and epilithic encrusting corallines (Lithothamnion sp.). Removal of G.pristoides from limpet shells revealed pits of a uniform size in the surface of the shells, into which the rhizoidal attachment organs of the seaweed penetrate. It is concluded that the horizontal distribution of G.pristoides is largely controlled by grazers (and "escapes" from grazing) and resistance to dislodgement by wave action. Based on present results, and considering some of the socio-economic factors associated with the Gelidium industry in South Africa, suggestions are made concerning the management and long-term maintenance of G.pristoides resources in the eastern Cape.
- Full Text:
- Date Issued: 1987
Studies on the biology of the economic marine red alga Gelidium pristoides (Turner) Kuetzing (Gelidiales : Rhodophyta)
- Authors: Carter, Alan Robert
- Date: 1987
- Subjects: Red algae Marine algae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4239 , http://hdl.handle.net/10962/d1004774
- Description: Various aspects of the biology of the intertidal agarophyte, Gelidium pristoides, were investigated, with the aim of providing information that would assist in formulating a management policy for this economic seaweed resource. G.pristoides occurs as tufts comprising as many as 40 individual plants, representing all three conspicuous life history stages, that are linked by the intertwining of their basal creeping axes. Individual plants consist of a system of branched creeping axes, which is largely responsible for colonizing surrounding substrata, from which one or more erect flattened fronds arise. These erect fronds may reach a height of 15 cm, and are irregularly bipinnately branched. Internal vegetative anatomy is generally typical of the genus. Morphological variation in mature plants is limited to increased plant height and branch density during the summer season. A dorso-ventrally flattened creeping habit was seen during early recruitment on flat rock surfaces and limpet shells within grazer exclusion plots, which developed into typical erect plants. Although there is a close taxonomic affinity between G.pristoides and the low-growing Gelidium turf, which occurs on wave-cut platforms in the eastern Cape (both produce bispores), the turf appears to represent a genetically divergent ecotype of the typical G.pristoides habit. In the light of present observations, it is suggested that the recent inclusion of G.pristoides in the new Onikusa genus should be questioned. Reproduction in G.pristoides is typical of the genus, except for the production of bispores, instead of tetraspores, in the sporophyte generation. The smaller nuclei in the binucleate bispores, in comparison to carpospores, suggested they are the product of normal meiosis (meiospores). This was confi rmed by chromosome counts of germl i ngs deri ved from bispores (n = 13-17) and carpospores (2n = 28-33). Throughout the geographical range of the seaweed, the bisporophyte generation is dominant over the combined male and female gametophyte generati on by a ratio of about 3 : 1. This imbalance may be due to bispores. G.pristoides a greater germination success of carpospores over plants are fertile throughout the year, while at Port Alfred there is no apparent seasonality in spore release. Growth of carpospore and bispore germlings is similar under various temperature treatments in culture. Optimum temperatures for growth were from 15-23°C, which corresponds with the sea temperatures experienced within the geographical range of the species . At Port Alfred, growth (linear frond elongation) and standing crop levels were maximal during summer . Ory weight levels were significantly inversely related to both growth and ash levels. Agar contents (% of dry weight) were generally greater in summer (48% ) than in winter (30%), and were inversely correlated with thallus nitrogen levels. Agar contents of distal plant halves were higher (8-15%) than in proximal halves. Regrowth of G.pristoides to original biomass or standing crop levels after harvesting, is similar for plucking and shearing at different times of the year. Regrowth is more rapid after spring and summer harvests (2-3 months) than after winter harvests (4-5 months). During the summer season, harvesting at monthly intervals showed significantly greater total yields, and production rates (e.g . 3.13 g. dry wt. / m2 / day for plucking) than under 3-monthly intervals (1.42 g. dry wt. / m2 / day for plucking). In contrast, average yields per harvest were Significantly greater when recovery period was longer (e.g. 3 months). Quadrats that were completely denuded failed to recover after a year, while regrowth was also retarded with increased elevation on the shore. Agar contents did not differ Significantly between plucked (38%) and sheared (42%) plant material. G.pristoides is distributed from about 0 . 2-0.75 m above MLWS, with a reduction in stature and frequency corresponding to increased elevation on the shore. Frond elongation rates, germling survival and recruitment within grazer-exclusion plots, is retarded with increased elevation level. Plants transplanted above the normal vertical range of the seaweed became severely bleached and died, while plants transplanted below the normal range of the seaweed (sub littoral fringe) senesced due to overgrowth by the epiphytic encrusting coralline, Polyporolithon patena (Hook . et Harv . ) Mason . G.pristoides recrui t ment in the sublittoral fri nge was enhanced with the exclusion of grazers . However, successful recruits were displaced due to smothering by articulated corallines (e.g. Corallina sp. and Jania sp. ) . G.pristoides is largely restricted to cracks and crevices in the rock, and also occurs on a large proportion of the available shells of the limpet Patella oculus Born., and to a lesser extent, shells of the barnacle Tetraclita serrata. G.pristoides recruitment was significantly enhanced by the exclusion of grazers (using toxic antifouling paint barriers). G.pristoides recruitment within the exclusion plots was significantly greater on artificially attached limpet shells (almost 100% cover) than on rock surfaces (20-30% cover), which occurred largely within cracks and crevies in the rocky substratum. ly attached to limpet G.pristoides plants are significantly more strongand barnacle shells than to rock and epilithic encrusting corallines (Lithothamnion sp.). Removal of G.pristoides from limpet shells revealed pits of a uniform size in the surface of the shells, into which the rhizoidal attachment organs of the seaweed penetrate. It is concluded that the horizontal distribution of G.pristoides is largely controlled by grazers (and "escapes" from grazing) and resistance to dislodgement by wave action. Based on present results, and considering some of the socio-economic factors associated with the Gelidium industry in South Africa, suggestions are made concerning the management and long-term maintenance of G.pristoides resources in the eastern Cape.
- Full Text:
- Date Issued: 1987
- Authors: Carter, Alan Robert
- Date: 1987
- Subjects: Red algae Marine algae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4239 , http://hdl.handle.net/10962/d1004774
- Description: Various aspects of the biology of the intertidal agarophyte, Gelidium pristoides, were investigated, with the aim of providing information that would assist in formulating a management policy for this economic seaweed resource. G.pristoides occurs as tufts comprising as many as 40 individual plants, representing all three conspicuous life history stages, that are linked by the intertwining of their basal creeping axes. Individual plants consist of a system of branched creeping axes, which is largely responsible for colonizing surrounding substrata, from which one or more erect flattened fronds arise. These erect fronds may reach a height of 15 cm, and are irregularly bipinnately branched. Internal vegetative anatomy is generally typical of the genus. Morphological variation in mature plants is limited to increased plant height and branch density during the summer season. A dorso-ventrally flattened creeping habit was seen during early recruitment on flat rock surfaces and limpet shells within grazer exclusion plots, which developed into typical erect plants. Although there is a close taxonomic affinity between G.pristoides and the low-growing Gelidium turf, which occurs on wave-cut platforms in the eastern Cape (both produce bispores), the turf appears to represent a genetically divergent ecotype of the typical G.pristoides habit. In the light of present observations, it is suggested that the recent inclusion of G.pristoides in the new Onikusa genus should be questioned. Reproduction in G.pristoides is typical of the genus, except for the production of bispores, instead of tetraspores, in the sporophyte generation. The smaller nuclei in the binucleate bispores, in comparison to carpospores, suggested they are the product of normal meiosis (meiospores). This was confi rmed by chromosome counts of germl i ngs deri ved from bispores (n = 13-17) and carpospores (2n = 28-33). Throughout the geographical range of the seaweed, the bisporophyte generation is dominant over the combined male and female gametophyte generati on by a ratio of about 3 : 1. This imbalance may be due to bispores. G.pristoides a greater germination success of carpospores over plants are fertile throughout the year, while at Port Alfred there is no apparent seasonality in spore release. Growth of carpospore and bispore germlings is similar under various temperature treatments in culture. Optimum temperatures for growth were from 15-23°C, which corresponds with the sea temperatures experienced within the geographical range of the species . At Port Alfred, growth (linear frond elongation) and standing crop levels were maximal during summer . Ory weight levels were significantly inversely related to both growth and ash levels. Agar contents (% of dry weight) were generally greater in summer (48% ) than in winter (30%), and were inversely correlated with thallus nitrogen levels. Agar contents of distal plant halves were higher (8-15%) than in proximal halves. Regrowth of G.pristoides to original biomass or standing crop levels after harvesting, is similar for plucking and shearing at different times of the year. Regrowth is more rapid after spring and summer harvests (2-3 months) than after winter harvests (4-5 months). During the summer season, harvesting at monthly intervals showed significantly greater total yields, and production rates (e.g . 3.13 g. dry wt. / m2 / day for plucking) than under 3-monthly intervals (1.42 g. dry wt. / m2 / day for plucking). In contrast, average yields per harvest were Significantly greater when recovery period was longer (e.g. 3 months). Quadrats that were completely denuded failed to recover after a year, while regrowth was also retarded with increased elevation on the shore. Agar contents did not differ Significantly between plucked (38%) and sheared (42%) plant material. G.pristoides is distributed from about 0 . 2-0.75 m above MLWS, with a reduction in stature and frequency corresponding to increased elevation on the shore. Frond elongation rates, germling survival and recruitment within grazer-exclusion plots, is retarded with increased elevation level. Plants transplanted above the normal vertical range of the seaweed became severely bleached and died, while plants transplanted below the normal range of the seaweed (sub littoral fringe) senesced due to overgrowth by the epiphytic encrusting coralline, Polyporolithon patena (Hook . et Harv . ) Mason . G.pristoides recrui t ment in the sublittoral fri nge was enhanced with the exclusion of grazers . However, successful recruits were displaced due to smothering by articulated corallines (e.g. Corallina sp. and Jania sp. ) . G.pristoides is largely restricted to cracks and crevices in the rock, and also occurs on a large proportion of the available shells of the limpet Patella oculus Born., and to a lesser extent, shells of the barnacle Tetraclita serrata. G.pristoides recruitment was significantly enhanced by the exclusion of grazers (using toxic antifouling paint barriers). G.pristoides recruitment within the exclusion plots was significantly greater on artificially attached limpet shells (almost 100% cover) than on rock surfaces (20-30% cover), which occurred largely within cracks and crevies in the rocky substratum. ly attached to limpet G.pristoides plants are significantly more strongand barnacle shells than to rock and epilithic encrusting corallines (Lithothamnion sp.). Removal of G.pristoides from limpet shells revealed pits of a uniform size in the surface of the shells, into which the rhizoidal attachment organs of the seaweed penetrate. It is concluded that the horizontal distribution of G.pristoides is largely controlled by grazers (and "escapes" from grazing) and resistance to dislodgement by wave action. Based on present results, and considering some of the socio-economic factors associated with the Gelidium industry in South Africa, suggestions are made concerning the management and long-term maintenance of G.pristoides resources in the eastern Cape.
- Full Text:
- Date Issued: 1987
Studies on the gastric proteases in three South African snake species
- Robertson, Sirion Sholto Douglas
- Authors: Robertson, Sirion Sholto Douglas
- Date: 1987
- Subjects: Snakes -- South Africa Proteolytic enzymes Pepsin Pepsinogen
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4063 , http://hdl.handle.net/10962/d1004639
- Description: The pepsinogens and pepsins of cobra, mole snake and puff adder have been studied. The pepsinogens of all three species fall into two distinct groups, here designated PI and PII. At least the latter group, in all cases, shows substantial microheterogeneity. Physicochemical studies suggest that the cobra and puff adder PII groups are more similar to each other than either is to the mole snake PII group. Kinetic studies indicate that, in the cobra and mole snake, the PI and PII pepsins differ in their Arrhenius activation energies. Such difference is smaller, or absent, in the case of the puff adder PI and PII pepsins. These characteristics of the pepsins are assessed in the context of the differences between the oral secretions of the three species studied. The suggestion is advanced that the puff adder's strongly proteolytic venom has influenced certain properties of its gastric proteases.
- Full Text:
- Date Issued: 1987
- Authors: Robertson, Sirion Sholto Douglas
- Date: 1987
- Subjects: Snakes -- South Africa Proteolytic enzymes Pepsin Pepsinogen
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4063 , http://hdl.handle.net/10962/d1004639
- Description: The pepsinogens and pepsins of cobra, mole snake and puff adder have been studied. The pepsinogens of all three species fall into two distinct groups, here designated PI and PII. At least the latter group, in all cases, shows substantial microheterogeneity. Physicochemical studies suggest that the cobra and puff adder PII groups are more similar to each other than either is to the mole snake PII group. Kinetic studies indicate that, in the cobra and mole snake, the PI and PII pepsins differ in their Arrhenius activation energies. Such difference is smaller, or absent, in the case of the puff adder PI and PII pepsins. These characteristics of the pepsins are assessed in the context of the differences between the oral secretions of the three species studied. The suggestion is advanced that the puff adder's strongly proteolytic venom has influenced certain properties of its gastric proteases.
- Full Text:
- Date Issued: 1987
Techniques of Xhosa music: a study based on the music of the Lumko district
- Authors: Dargie, David John
- Date: 1987
- Subjects: Xhosa (African people) -- Music , Lumko district , Eastern Cape (South Africa) , Xhosa music , Musicology , AbaThembu , Ntsikana , Songs , Musical bows , Overtone singing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2630 , http://hdl.handle.net/10962/d1001975
- Description: Part 1.Thesis: Chapter 1: The people of the Lumko district (the villages of Ngqoko and Sikhwankqeni) are AbaThembu, mostly of the Gcina clan cluster. Their history has caused them to be linked with (now vanished) San peoples in special ways, which have undoubtedly influenced their music. Chapter 2: The music of these people is centred around their religious and social life. This affects the way they classify their songs; and song classifications (and the way songs are used) affect their performance, in particular, the dance styles associated with the song classes. Chapter 3: A variety of musical instruments is used in the Lumko district, the most important being the musical bows. Once again, the use of these bows gives an insight into the musical influences that have affected the people historically. The ways the bows work are described, as well as ways to play them. Chapter 4: Overtone singing, not previously documented anywhere in traditional African music, is practised in certain ways by these AmaGcina. These, and other vocal techniques, are described. Chapter 5: From the terminology and the methods of conceptualisation about music in the Lumko district, it is possible to gain an insight into a truly Xhosa technical understanding of Xhosa music. Once again a historical insight is gained, because so many of the important terms are KhoiSan words. Chapter 6: A Western technological (i. e. musicological) understanding of the music is also necessary in a study of this nature. This chapter applies musicological concepts to an examination of the relationship between speech and song, of the usages in melody and scale, harmony theory, rhythm, polyphony, song form, instrumental roles and methods of performance. Chapter 7: This is the conclusion of the thesis. It sums up what has been studied: musical techniques, principles, the importance of Ntsikana 's song as a basis for musical comparisons, and the import of the historical aspects of the study - a possible glimpse of the music of the San. PART 2. MUSIC TRANSCRIPTIONS AND DESCRIPTIONS. The transcriptions of 62 songs provide the material for this study. The songs were chosen to represent all the major song classes used in the Lumko district, and to represent all the important music techniques as well. The songs are in fifteen categories. Each song is accompanied by its technical details, and sufficient commentary to make the song transcription intelligible and meaningful. Certain key songs are chosen as type-songs or other special examples, and are used as the bases for discussion on song style characteristics, principles of performance, bow adaptation, and so on. A general Introduction to Part 2 describes and accounts for the method of transcription, and also attempts to make it possible for the score reader not only to analyse, but also to perform the songs. In a further attempt to bring the transcriptions to life, a video recording of certain key songs and techniques, and audio tapes with examples taken from all the songs, accompany this study
- Full Text:
- Date Issued: 1987
- Authors: Dargie, David John
- Date: 1987
- Subjects: Xhosa (African people) -- Music , Lumko district , Eastern Cape (South Africa) , Xhosa music , Musicology , AbaThembu , Ntsikana , Songs , Musical bows , Overtone singing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2630 , http://hdl.handle.net/10962/d1001975
- Description: Part 1.Thesis: Chapter 1: The people of the Lumko district (the villages of Ngqoko and Sikhwankqeni) are AbaThembu, mostly of the Gcina clan cluster. Their history has caused them to be linked with (now vanished) San peoples in special ways, which have undoubtedly influenced their music. Chapter 2: The music of these people is centred around their religious and social life. This affects the way they classify their songs; and song classifications (and the way songs are used) affect their performance, in particular, the dance styles associated with the song classes. Chapter 3: A variety of musical instruments is used in the Lumko district, the most important being the musical bows. Once again, the use of these bows gives an insight into the musical influences that have affected the people historically. The ways the bows work are described, as well as ways to play them. Chapter 4: Overtone singing, not previously documented anywhere in traditional African music, is practised in certain ways by these AmaGcina. These, and other vocal techniques, are described. Chapter 5: From the terminology and the methods of conceptualisation about music in the Lumko district, it is possible to gain an insight into a truly Xhosa technical understanding of Xhosa music. Once again a historical insight is gained, because so many of the important terms are KhoiSan words. Chapter 6: A Western technological (i. e. musicological) understanding of the music is also necessary in a study of this nature. This chapter applies musicological concepts to an examination of the relationship between speech and song, of the usages in melody and scale, harmony theory, rhythm, polyphony, song form, instrumental roles and methods of performance. Chapter 7: This is the conclusion of the thesis. It sums up what has been studied: musical techniques, principles, the importance of Ntsikana 's song as a basis for musical comparisons, and the import of the historical aspects of the study - a possible glimpse of the music of the San. PART 2. MUSIC TRANSCRIPTIONS AND DESCRIPTIONS. The transcriptions of 62 songs provide the material for this study. The songs were chosen to represent all the major song classes used in the Lumko district, and to represent all the important music techniques as well. The songs are in fifteen categories. Each song is accompanied by its technical details, and sufficient commentary to make the song transcription intelligible and meaningful. Certain key songs are chosen as type-songs or other special examples, and are used as the bases for discussion on song style characteristics, principles of performance, bow adaptation, and so on. A general Introduction to Part 2 describes and accounts for the method of transcription, and also attempts to make it possible for the score reader not only to analyse, but also to perform the songs. In a further attempt to bring the transcriptions to life, a video recording of certain key songs and techniques, and audio tapes with examples taken from all the songs, accompany this study
- Full Text:
- Date Issued: 1987
The acquisition of reading skills in English by coloured primary school children whose home language is Afrikaans : a developmental study conducted in a specific South African community
- Authors: Pitt, Joe Harrison
- Date: 1987
- Subjects: Reading (Primary) -- South Africa Reading (Elementary) -- South Africa English language -- Study and teaching (Primary) -- Afrikaans speakers English language -- Study and teaching -- South Africa -- Foreign speakers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2338 , http://hdl.handle.net/10962/d1002020
- Description: This research studies the acquisition and development of specific reading skills in English by "Coloured" primary school children for whom English is a second language. This study involves both oral and silent reading research. Developmental trends in both modes of reading are compared with those established for reading in Afrikaans in order to ascertain whether any transfer takes place from Afrikaans to English. For analysis of data obtained from oral reading, this researcher adopted an error analysis method devised by Kenneth Goodman (1973), viz. Miscue Analysis (MA). Readers read a passage and their miscues were recorded. From the miscues this researcher established, for the different standards: the frequencies of miscues; readers' ability to associate sound and symbol; sensitivity to grammar; meaning access; and correction strategies. In the silent reading research, readers' performances in a test battery of eight sub-tests provide insights into the presence or absence of information processing skills. Readability levels (Singer and Donlan (1980), discrimination index and facility value (Heaton 1975), and Chi-Square Statistics (Roscoe 1969) determine the development of specific reading skills, viz.: utilization of textual cues; understanding cause and effect relationships and sequence; previewing and anticipation; scanning, referring and synthesizing; understanding text structure and coherence; understanding propositional development; understanding synonymy and antonimy; and understanding communicative value. Grellet (1981), Kennedy (1981), and Harri-Augstein (1982), inter alia, regard these skills as crucial to efficient text processing. Analyses of data show there are developmental patterns, but skills emerge 1 - 3 years late when compared with results obtained by Kennedy (1981 ) and develop at a retarded and erratic pace. The readers in all the standards have not mastered the skills sufficiently to process text efficiently. This research shows that Std 3 is a cut-off level where a transition takes place from lower-order to higher-order skills processing. In addition, Chi-Square Statistics show little transfer from Afrikaans to English; the skills develop independently in the two languages. Enquiry has identified various factors that influence skills deficiencies, viz.: syllabus prescriptions and problems of interpretation; teachers' understanding of the reading process and the methods employed; teacher-training progresses; materials prescribed for reading; and reading in the society. This research recommends ways in which short comings can be remedied
- Full Text:
- Date Issued: 1987
- Authors: Pitt, Joe Harrison
- Date: 1987
- Subjects: Reading (Primary) -- South Africa Reading (Elementary) -- South Africa English language -- Study and teaching (Primary) -- Afrikaans speakers English language -- Study and teaching -- South Africa -- Foreign speakers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2338 , http://hdl.handle.net/10962/d1002020
- Description: This research studies the acquisition and development of specific reading skills in English by "Coloured" primary school children for whom English is a second language. This study involves both oral and silent reading research. Developmental trends in both modes of reading are compared with those established for reading in Afrikaans in order to ascertain whether any transfer takes place from Afrikaans to English. For analysis of data obtained from oral reading, this researcher adopted an error analysis method devised by Kenneth Goodman (1973), viz. Miscue Analysis (MA). Readers read a passage and their miscues were recorded. From the miscues this researcher established, for the different standards: the frequencies of miscues; readers' ability to associate sound and symbol; sensitivity to grammar; meaning access; and correction strategies. In the silent reading research, readers' performances in a test battery of eight sub-tests provide insights into the presence or absence of information processing skills. Readability levels (Singer and Donlan (1980), discrimination index and facility value (Heaton 1975), and Chi-Square Statistics (Roscoe 1969) determine the development of specific reading skills, viz.: utilization of textual cues; understanding cause and effect relationships and sequence; previewing and anticipation; scanning, referring and synthesizing; understanding text structure and coherence; understanding propositional development; understanding synonymy and antonimy; and understanding communicative value. Grellet (1981), Kennedy (1981), and Harri-Augstein (1982), inter alia, regard these skills as crucial to efficient text processing. Analyses of data show there are developmental patterns, but skills emerge 1 - 3 years late when compared with results obtained by Kennedy (1981 ) and develop at a retarded and erratic pace. The readers in all the standards have not mastered the skills sufficiently to process text efficiently. This research shows that Std 3 is a cut-off level where a transition takes place from lower-order to higher-order skills processing. In addition, Chi-Square Statistics show little transfer from Afrikaans to English; the skills develop independently in the two languages. Enquiry has identified various factors that influence skills deficiencies, viz.: syllabus prescriptions and problems of interpretation; teachers' understanding of the reading process and the methods employed; teacher-training progresses; materials prescribed for reading; and reading in the society. This research recommends ways in which short comings can be remedied
- Full Text:
- Date Issued: 1987
The development of athletics in South Africa: 1814 to 1914
- Authors: Coghlan, Douglas Victor
- Date: 1987
- Subjects: Athletics -- South Africa -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60785 , vital:27830
- Description: The purpose of this study was to record the development of athletics in South Africa from 1814 to 1914. This period was chosen because sport and athletics originated and developed a social institution during that time and the First World brought progress to a temporary halt, after which there were many new developments. The Cape Colony became British in 1814, and it was British influence that played such a dominant role in the social history of the period.
- Full Text:
- Date Issued: 1987
- Authors: Coghlan, Douglas Victor
- Date: 1987
- Subjects: Athletics -- South Africa -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/60785 , vital:27830
- Description: The purpose of this study was to record the development of athletics in South Africa from 1814 to 1914. This period was chosen because sport and athletics originated and developed a social institution during that time and the First World brought progress to a temporary halt, after which there were many new developments. The Cape Colony became British in 1814, and it was British influence that played such a dominant role in the social history of the period.
- Full Text:
- Date Issued: 1987
The law of culpable homicide in South Africa : with reference to the law of manslaughter in English law and the law related to negligent killing in German law
- Authors: du Plessis, J R
- Date: 1987
- Subjects: Homicide -- Law and legislation -- South Africa Homicide -- Law and legislation -- England Homicide -- Law and legislation -- Germany (West)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3670 , http://hdl.handle.net/10962/d1003185
- Description: Culpable homicide is the unlawful negligent killing of a fellow human being. As such it is in many respects a 'residual' crime being the verdict prosecutors may expect when they are unable to prove the intention to kill when prosecuting for murder. A feature of this was that in the past when defences such as, for instance, intoxication or provocation were raised at murder trials, convictions of culpable homicide were almost automatic. In recent years, under the influence of the 'purist' current in our Criminal law, intoxication has become a defence to culpable homicide and provocation resulting in loss of self-control has also become a defence to culpable homicide. These developments are unacceptable to some writers on criminal law and a move away from the purist approach to the 'traditional' or pragmatic approach is to be expected. Greater emphasis will be placed on practical results than on the achievement of logical consistency. This could result in the law of culpable homicide becoming more socially effective than it is at present.
- Full Text:
- Date Issued: 1987
- Authors: du Plessis, J R
- Date: 1987
- Subjects: Homicide -- Law and legislation -- South Africa Homicide -- Law and legislation -- England Homicide -- Law and legislation -- Germany (West)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3670 , http://hdl.handle.net/10962/d1003185
- Description: Culpable homicide is the unlawful negligent killing of a fellow human being. As such it is in many respects a 'residual' crime being the verdict prosecutors may expect when they are unable to prove the intention to kill when prosecuting for murder. A feature of this was that in the past when defences such as, for instance, intoxication or provocation were raised at murder trials, convictions of culpable homicide were almost automatic. In recent years, under the influence of the 'purist' current in our Criminal law, intoxication has become a defence to culpable homicide and provocation resulting in loss of self-control has also become a defence to culpable homicide. These developments are unacceptable to some writers on criminal law and a move away from the purist approach to the 'traditional' or pragmatic approach is to be expected. Greater emphasis will be placed on practical results than on the achievement of logical consistency. This could result in the law of culpable homicide becoming more socially effective than it is at present.
- Full Text:
- Date Issued: 1987
The piano sonatas of Muzio Clementi: an investigation into compositional aspects with special emphasis on developments in form and style
- Authors: Radloff, T E K
- Date: 1987
- Subjects: Clementi, Muzio, 1752-1832 -- Sonatas, Piano
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2653 , http://hdl.handle.net/10962/d1002319
- Description: This thesis follows on a number of studies all of which deal with selected schools of composition important in the development of the piano sonata. Muzio Clementi was one of the leading contemporaries of such great masters as Haydn. Mozart, Beethoven and Schubert, all of whom contributed greatly to the repertoire of piano sonatas. During his lifetime his reputation equalled that of his contemporaries and many of his sonatas were greatly admired by the young Beethoven. Clementi was born in Rome but spent the largest part of his Ii in London where he established himself as a multi-faceted musician, being engaged in many different fields connected with music: composer, teacher, performer, publisher and manufacturer of pianos. His sonatas form the most important part of his total creative output. While the earli works still follow principles typical of the middle classical period, his later sonatas belong to a different era and foreshadow the coming of romanticism. This thesis is devoted to a detailed survey of the changes that affect the form of the various movements. It shows the gradual change from tile simple compositional methods of the early works to the inherent logical process that characterises the sonatas of the later years The first part of the thesis culminates in findings that prove Clementi IS individuality and show that his enquiring spirit makes him an innovator of the first rank. The second major part of the thesis deals with the stylistic changes that take place within the various periods of Clementiis creative life. It summarises the main ingredients of his early music, critically evaluates the importance of various pianistic devices that play a leading role in works of the middle periods and finally shows the successful blending of inherited and new techniques in the last sonatas. The concluding section details the major points of the preceding investigations and presents a picture of Clementi's personality as it emerges through the medium of his solo keyboard sonatas.
- Full Text:
- Date Issued: 1987
- Authors: Radloff, T E K
- Date: 1987
- Subjects: Clementi, Muzio, 1752-1832 -- Sonatas, Piano
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2653 , http://hdl.handle.net/10962/d1002319
- Description: This thesis follows on a number of studies all of which deal with selected schools of composition important in the development of the piano sonata. Muzio Clementi was one of the leading contemporaries of such great masters as Haydn. Mozart, Beethoven and Schubert, all of whom contributed greatly to the repertoire of piano sonatas. During his lifetime his reputation equalled that of his contemporaries and many of his sonatas were greatly admired by the young Beethoven. Clementi was born in Rome but spent the largest part of his Ii in London where he established himself as a multi-faceted musician, being engaged in many different fields connected with music: composer, teacher, performer, publisher and manufacturer of pianos. His sonatas form the most important part of his total creative output. While the earli works still follow principles typical of the middle classical period, his later sonatas belong to a different era and foreshadow the coming of romanticism. This thesis is devoted to a detailed survey of the changes that affect the form of the various movements. It shows the gradual change from tile simple compositional methods of the early works to the inherent logical process that characterises the sonatas of the later years The first part of the thesis culminates in findings that prove Clementi IS individuality and show that his enquiring spirit makes him an innovator of the first rank. The second major part of the thesis deals with the stylistic changes that take place within the various periods of Clementiis creative life. It summarises the main ingredients of his early music, critically evaluates the importance of various pianistic devices that play a leading role in works of the middle periods and finally shows the successful blending of inherited and new techniques in the last sonatas. The concluding section details the major points of the preceding investigations and presents a picture of Clementi's personality as it emerges through the medium of his solo keyboard sonatas.
- Full Text:
- Date Issued: 1987
The role of the self-concept in a system of guidance at the level of initial adolescence
- Authors: Hall, Deryck John
- Date: 1987
- Subjects: Self-perception in adolescence , Educational counseling
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1382 , http://hdl.handle.net/10962/d1001448
- Description: Part One I A Perspective on Guidance II Concepts of Self This section is a review and discussion of the two conceptualizations which are fundamental to the research structure: guidance as an overall framework within which procedures are devised for the development of this understanding of the "self" . Part Two • III Didactic Discovery IV The Class Citation Award A way of thinking about an ~ducational approach which could generate a classroom mileu, where the in a practical ongoing process to encourage participation and CCA is the key~ote strategy involve the group in "self" and "other" awareness. Part Three V VI Experiment, Survey, Action Research Results, Reflections and Recommendations The three research methods employed to gather evidence of pupil awareness and its implications, with a discussion patterns of self~knowledge, and its effect on the NOTE: Constant reference to thi s page, and to page xxxii will enable the reader to view the thesis as a whole
- Full Text:
- Date Issued: 1987
- Authors: Hall, Deryck John
- Date: 1987
- Subjects: Self-perception in adolescence , Educational counseling
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1382 , http://hdl.handle.net/10962/d1001448
- Description: Part One I A Perspective on Guidance II Concepts of Self This section is a review and discussion of the two conceptualizations which are fundamental to the research structure: guidance as an overall framework within which procedures are devised for the development of this understanding of the "self" . Part Two • III Didactic Discovery IV The Class Citation Award A way of thinking about an ~ducational approach which could generate a classroom mileu, where the in a practical ongoing process to encourage participation and CCA is the key~ote strategy involve the group in "self" and "other" awareness. Part Three V VI Experiment, Survey, Action Research Results, Reflections and Recommendations The three research methods employed to gather evidence of pupil awareness and its implications, with a discussion patterns of self~knowledge, and its effect on the NOTE: Constant reference to thi s page, and to page xxxii will enable the reader to view the thesis as a whole
- Full Text:
- Date Issued: 1987
Xhosa beer drinks and their oratory
- Authors: McAllister, Patrick A
- Date: 1987
- Subjects: Beer -- Social aspects -- South Africa , Drinking customs -- South Africa , Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2120 , http://hdl.handle.net/10962/d1012863
- Description: This is a study of 'beer drinks' among Xhosa people living in the Shixini administrative area of Willowvale district, Transkei. Beer drinks are defined as a 'polythetic' class of events distinguishable from other kinds of ceremonies and rituals at which beer may be consumed, and an attempt is made to outline their major characteristics. A detailed description of the way in which beer drinks are conducted is provided in Chapter 3, with emphasis on the symbolism involved in the allocation of beer, space and time, and on the speech events (including formal oratory) that occur. The main theoretical argument is that beer drinks may be regarded as 'cultural performances' in which social reality or 'practice' is dramatised and reflected upon, enabling people to infuse their experience with meaning and to establish guidelines for future action. This is achieved by relating social practice to cultural norms and values, in a dynamic rather than a static manner. It is demonstrated that the symbolism involved in beer drinking is highly sensitive to the real world and adjusts accordingly, which means that 'culture' is continually being reinterpreted. Despite poverty, a degree of landlessness and heavy reliance on migrant labour, Shixini people maintain an ideal of rural selfsufficiency and are able to partly fulfill this ideal, thereby maintaining a degree of independence and resistance to full incorporation into the wider political economy of southern Africa. They achieve this largely by maintaining a strong sense of community and of household interdependence, linked to a sense of Xhosa tradition. It is this aspect of social practice, manifested in a variety of forms - work parties, ploughing companies, rites of passage, and so on - that is dramatised, reflected upon and reinforced at beer drinks. In a definite sense then, beer drinks may be regarded as a response and a way of adapting to apartheid, and this study one of a community under threat.
- Full Text:
- Date Issued: 1987
- Authors: McAllister, Patrick A
- Date: 1987
- Subjects: Beer -- Social aspects -- South Africa , Drinking customs -- South Africa , Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2120 , http://hdl.handle.net/10962/d1012863
- Description: This is a study of 'beer drinks' among Xhosa people living in the Shixini administrative area of Willowvale district, Transkei. Beer drinks are defined as a 'polythetic' class of events distinguishable from other kinds of ceremonies and rituals at which beer may be consumed, and an attempt is made to outline their major characteristics. A detailed description of the way in which beer drinks are conducted is provided in Chapter 3, with emphasis on the symbolism involved in the allocation of beer, space and time, and on the speech events (including formal oratory) that occur. The main theoretical argument is that beer drinks may be regarded as 'cultural performances' in which social reality or 'practice' is dramatised and reflected upon, enabling people to infuse their experience with meaning and to establish guidelines for future action. This is achieved by relating social practice to cultural norms and values, in a dynamic rather than a static manner. It is demonstrated that the symbolism involved in beer drinking is highly sensitive to the real world and adjusts accordingly, which means that 'culture' is continually being reinterpreted. Despite poverty, a degree of landlessness and heavy reliance on migrant labour, Shixini people maintain an ideal of rural selfsufficiency and are able to partly fulfill this ideal, thereby maintaining a degree of independence and resistance to full incorporation into the wider political economy of southern Africa. They achieve this largely by maintaining a strong sense of community and of household interdependence, linked to a sense of Xhosa tradition. It is this aspect of social practice, manifested in a variety of forms - work parties, ploughing companies, rites of passage, and so on - that is dramatised, reflected upon and reinforced at beer drinks. In a definite sense then, beer drinks may be regarded as a response and a way of adapting to apartheid, and this study one of a community under threat.
- Full Text:
- Date Issued: 1987
A study of universal algebras in fuzzy set theory
- Authors: Murali, V
- Date: 1988
- Subjects: Fuzzy sets Algebra, Universal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5394 , http://hdl.handle.net/10962/d1001983
- Description: This thesis attempts a synthesis of two important and fast developing branches of mathematics, namely universal algebra and fuzzy set theory. Given an abstract algebra [X,F] where X is a non-empty set and F is a set of finitary operations on X, a fuzzy algebra [I×,F] is constructed by extending operations on X to that on I×, the set of fuzzy subsets of X (I denotes the unit interval), using Zadeh's extension principle. Homomorphisms between fuzzy algebras are defined and discussed. Fuzzy subalgebras of an algebra are defined to be elements of a fuzzy algebra which respect the extended algebra operations under inclusion of fuzzy subsets. The family of fuzzy subalgebras of an algebra is an algebraic closure system in I×. Thus the set of fuzzy subalgebras is a complete lattice. A fuzzy equivalence relation on a set is defined and a partition of such a relation into a class of fuzzy subsets is derived. Using these ideas, fuzzy functions between sets, fuzzy congruence relations, and fuzzy homomorphisms are defined. The kernels of fuzzy homomorphisms are proved to be fuzzy congruence relations, paving the way for the fuzzy isomorphism theorem. Finally, we sketch some ideas on free fuzzy subalgebras and polynomial algebras. In a nutshell, we can say that this thesis treats the central ideas of universal algebras, namely subalgebras, homomorphisms, equivalence and congruence relations, isomorphism theorems and free algebra in the fuzzy set theory setting
- Full Text:
- Date Issued: 1988
- Authors: Murali, V
- Date: 1988
- Subjects: Fuzzy sets Algebra, Universal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5394 , http://hdl.handle.net/10962/d1001983
- Description: This thesis attempts a synthesis of two important and fast developing branches of mathematics, namely universal algebra and fuzzy set theory. Given an abstract algebra [X,F] where X is a non-empty set and F is a set of finitary operations on X, a fuzzy algebra [I×,F] is constructed by extending operations on X to that on I×, the set of fuzzy subsets of X (I denotes the unit interval), using Zadeh's extension principle. Homomorphisms between fuzzy algebras are defined and discussed. Fuzzy subalgebras of an algebra are defined to be elements of a fuzzy algebra which respect the extended algebra operations under inclusion of fuzzy subsets. The family of fuzzy subalgebras of an algebra is an algebraic closure system in I×. Thus the set of fuzzy subalgebras is a complete lattice. A fuzzy equivalence relation on a set is defined and a partition of such a relation into a class of fuzzy subsets is derived. Using these ideas, fuzzy functions between sets, fuzzy congruence relations, and fuzzy homomorphisms are defined. The kernels of fuzzy homomorphisms are proved to be fuzzy congruence relations, paving the way for the fuzzy isomorphism theorem. Finally, we sketch some ideas on free fuzzy subalgebras and polynomial algebras. In a nutshell, we can say that this thesis treats the central ideas of universal algebras, namely subalgebras, homomorphisms, equivalence and congruence relations, isomorphism theorems and free algebra in the fuzzy set theory setting
- Full Text:
- Date Issued: 1988
Application of high-performance liquid chromatography to the analysis, stability and pharmacokinetics of erythromycin
- Authors: Stubbs, Christopher
- Date: 1988
- Subjects: Erythromycin High performance liquid chromatography
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3809 , http://hdl.handle.net/10962/d1004372
- Description: Erythromycin is a macrolide antibiotic used mainly in the treatment of infections caused by gram-positive organisms. Erythromycin base is rap idly degraded in acidic media necessitating the use of structurally modified erythromycin derivatives or acid resistant dosage forms in order to decrease gastric inactivation of the drug. The majority of pharmacokinetic studies to-date have utilized relatively non-specific microbiological assay procedures which are unable to differentiate between concentrations of active erythromycin base and the inactive pro-drug derivatives. A high-performance liquid chromatographic (HPLC) technique is described for the simultaneous determination of erythromycin base and propionate (inactive pro-drug form) in human serum and urine following the oral administration of erythromycin estolate, an acid stable derivative of erythromycin. The method involves a solid-phase extraction step prior to chromatography on a C18 reversed-phase column with coulometric electrochemical detection. Sample handling and storage techniques are presented which minimize hydrolysis of the inactive ester moiety between sample collection and analysis, thereby more accurately reflecting the in vivo situation than in previously published studies. Results from single dose pharmacokinetic studies indicate that only 10-15% of the total erythromycin concentration in vivo is present as the active base component following oral administration of erythromycin estolate. This percentage increases to approximately 25% during multiple dose administration. Novel urinary excretion data are presented which reveal that approximately 40% and 55% of the total erythromycin excreted in urine is excreted as erythromycin base following single and multiple dosages respectively. Computer fitting of mean serum concentration-time data revealed that an open one compartment model with linear first order absorption and elimination best described the absorption and disposition of erythromycin, although poor computer fits for individual data sets were observed. Some evidence of non-linear elimination is presented utilizing both compartmental and non-compartmental pharmacokinetic techniques. Large intra-and inter-personal variability in erythromycin absorption and disposition was experienced which was evaluated in five subjects who each received one 500 mg erythromycin estolate tablet from the same batch, on three separate occasions. In addition. an HPLC method is described for the analysis of "total erythromycin" concentrations following erythromycin estolate administration which involves hydrolysis of the ester component prior to chromatography. as well as an HPLC method utilizing amperometric electrochemical detection capable of monitoring the stability of erythromycin base in stored biological fluids. These methods were uti I ized in various stability studies involving erythromycin base and propionate as well as for the analysis of erythromycin estolate dosage forms.
- Full Text:
- Date Issued: 1988
- Authors: Stubbs, Christopher
- Date: 1988
- Subjects: Erythromycin High performance liquid chromatography
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3809 , http://hdl.handle.net/10962/d1004372
- Description: Erythromycin is a macrolide antibiotic used mainly in the treatment of infections caused by gram-positive organisms. Erythromycin base is rap idly degraded in acidic media necessitating the use of structurally modified erythromycin derivatives or acid resistant dosage forms in order to decrease gastric inactivation of the drug. The majority of pharmacokinetic studies to-date have utilized relatively non-specific microbiological assay procedures which are unable to differentiate between concentrations of active erythromycin base and the inactive pro-drug derivatives. A high-performance liquid chromatographic (HPLC) technique is described for the simultaneous determination of erythromycin base and propionate (inactive pro-drug form) in human serum and urine following the oral administration of erythromycin estolate, an acid stable derivative of erythromycin. The method involves a solid-phase extraction step prior to chromatography on a C18 reversed-phase column with coulometric electrochemical detection. Sample handling and storage techniques are presented which minimize hydrolysis of the inactive ester moiety between sample collection and analysis, thereby more accurately reflecting the in vivo situation than in previously published studies. Results from single dose pharmacokinetic studies indicate that only 10-15% of the total erythromycin concentration in vivo is present as the active base component following oral administration of erythromycin estolate. This percentage increases to approximately 25% during multiple dose administration. Novel urinary excretion data are presented which reveal that approximately 40% and 55% of the total erythromycin excreted in urine is excreted as erythromycin base following single and multiple dosages respectively. Computer fitting of mean serum concentration-time data revealed that an open one compartment model with linear first order absorption and elimination best described the absorption and disposition of erythromycin, although poor computer fits for individual data sets were observed. Some evidence of non-linear elimination is presented utilizing both compartmental and non-compartmental pharmacokinetic techniques. Large intra-and inter-personal variability in erythromycin absorption and disposition was experienced which was evaluated in five subjects who each received one 500 mg erythromycin estolate tablet from the same batch, on three separate occasions. In addition. an HPLC method is described for the analysis of "total erythromycin" concentrations following erythromycin estolate administration which involves hydrolysis of the ester component prior to chromatography. as well as an HPLC method utilizing amperometric electrochemical detection capable of monitoring the stability of erythromycin base in stored biological fluids. These methods were uti I ized in various stability studies involving erythromycin base and propionate as well as for the analysis of erythromycin estolate dosage forms.
- Full Text:
- Date Issued: 1988
Aspects of the transdermal permeation and analysis of betamethasone 17-valerate
- Authors: Smith, Eric W
- Date: 1988
- Subjects: Transdermal medication Skin absorption Dermatologic agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3815 , http://hdl.handle.net/10962/d1004741
- Description: The current world-wide interest in transdermal drug delivery makes the prospect of valid in vitro diffusion cell methodology highly attractive. A new laboratory diffusion cell has been designed and constructed based on theoretical principles and practical permeation reports surveyed in recent literature, and has been applied to the monitoring of betamethasone 17-valerate permeation. The cell performance has been validated with respect to hydrodynamic mixing efficiency and temperature of the receptor phase. The steady-state permeation of this corticosteroid has been monitored through various synthetic and animal membranes in order to select the most appropriate media for in vitro study. The permeation of betamethasone 17-valerate has been monitored from various types of commercial and extemporaneously prepared semisolid topical formulation (cream, lotion, ointment and scalp application), through silicone membrane, human and weanling pig stratum corneum, and full thickness hairless mouse skin, and these in vitro results have been compared to data from in vivo blanching assays, using the same formulations, in an attempt to correlate the findings. This experimental methodology has necessitated the development of ancillary analytical techniques. A column-switching high-performance liquid chromatographic method has been developed for the rapid on-line clean-up and analysis of betamethasone 17-valerate contained in the various topical formulations, which minimizes sample handling and extraction procedures. The method has been modified for the analysis of this corticosteroid in the isopropyl myristate receptor phase used in the in vitro permeation experiments, and scintillation counting of tritium-labelled water has been used to verify the integrity of the animal membranes. The comparison of in vitro permeation and in vivo blanching results indicate good correlation of the data in certain instances. The closest correlations have been observed when the human stratum corneum has been used in vitro and these results are compared to data from the occluded mode of the blanching assay. The results of the porcine and murine media have also correlated with the human in vivo data, whereas the silicone membrane appears applicable only in certain in vitro experiments. The results indicate that valid, comparative percutaneous absorption data may be obtained in vitro by using a well designed, validated diffusion cell system.
- Full Text:
- Date Issued: 1988
- Authors: Smith, Eric W
- Date: 1988
- Subjects: Transdermal medication Skin absorption Dermatologic agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3815 , http://hdl.handle.net/10962/d1004741
- Description: The current world-wide interest in transdermal drug delivery makes the prospect of valid in vitro diffusion cell methodology highly attractive. A new laboratory diffusion cell has been designed and constructed based on theoretical principles and practical permeation reports surveyed in recent literature, and has been applied to the monitoring of betamethasone 17-valerate permeation. The cell performance has been validated with respect to hydrodynamic mixing efficiency and temperature of the receptor phase. The steady-state permeation of this corticosteroid has been monitored through various synthetic and animal membranes in order to select the most appropriate media for in vitro study. The permeation of betamethasone 17-valerate has been monitored from various types of commercial and extemporaneously prepared semisolid topical formulation (cream, lotion, ointment and scalp application), through silicone membrane, human and weanling pig stratum corneum, and full thickness hairless mouse skin, and these in vitro results have been compared to data from in vivo blanching assays, using the same formulations, in an attempt to correlate the findings. This experimental methodology has necessitated the development of ancillary analytical techniques. A column-switching high-performance liquid chromatographic method has been developed for the rapid on-line clean-up and analysis of betamethasone 17-valerate contained in the various topical formulations, which minimizes sample handling and extraction procedures. The method has been modified for the analysis of this corticosteroid in the isopropyl myristate receptor phase used in the in vitro permeation experiments, and scintillation counting of tritium-labelled water has been used to verify the integrity of the animal membranes. The comparison of in vitro permeation and in vivo blanching results indicate good correlation of the data in certain instances. The closest correlations have been observed when the human stratum corneum has been used in vitro and these results are compared to data from the occluded mode of the blanching assay. The results of the porcine and murine media have also correlated with the human in vivo data, whereas the silicone membrane appears applicable only in certain in vitro experiments. The results indicate that valid, comparative percutaneous absorption data may be obtained in vitro by using a well designed, validated diffusion cell system.
- Full Text:
- Date Issued: 1988
Aspekte van die Judaïes-Christelike en die Boeddhistiese in die poësie van Breyten Breytenbach
- Authors: Ferreira, Jeanette
- Date: 1988
- Subjects: Breytenbach, Breyten Afrikaans poetry -- History and criticism , Breytenbach, Breyten -- Criticism and interpretation
- Language: Afrikaans
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3574 , http://hdl.handle.net/10962/d1002097
- Description: Concepts of life and death, time and self-denial are investigated in the poetry of Breyten Breytenbach, with specific reference to the similarities and differences between the Judeo-Christian and the Buddhist traditions. Biblical references in the poetry are examined, and their underlying concepts compared to related concepts in Tantric Buddhism and Zen-Buddhism. The conclusion is drawn that the biblical concepts are transposed in the poetry in order to create Buddhist concepts of life and death, time and a form of self-denial. De-sacralisation of the Christian. concepts is inevitable in this creative process. However, the primary intention of the author is not de-sacralisation, but the implementation 'of the Buddhist philosophy of life in which everything is experienced as "totally one". A comparison between the reconstructed intended reader of Breytenbach's poetry and elements of the Afrikaans reading public suggests that political comment on segregated South African society is intended. Breytenbach's poetry is compared to canonized Afrikaans poetry with respect to Buddhist influence, national protest, aspiration to holiness and transposed biblical concepts. The conclusion is that his poetry is highly innovative in these respects. In the broader spectrum of South African literature his poetry is compared, with reference to transposed biblical concepts and national protest, to the poetry of Black poets writing in English, and (where material is available) to those writing in Afrikaans. The conclusion is that Breytenbach's poetry is strongly linked to this poetry. However, the complexity of Breytenbach's poetry, and the advanced aesthetic level and linguistic code required of the intended reader determine his placing within the canon of Afrikaans poetry.
- Full Text:
- Date Issued: 1988
- Authors: Ferreira, Jeanette
- Date: 1988
- Subjects: Breytenbach, Breyten Afrikaans poetry -- History and criticism , Breytenbach, Breyten -- Criticism and interpretation
- Language: Afrikaans
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3574 , http://hdl.handle.net/10962/d1002097
- Description: Concepts of life and death, time and self-denial are investigated in the poetry of Breyten Breytenbach, with specific reference to the similarities and differences between the Judeo-Christian and the Buddhist traditions. Biblical references in the poetry are examined, and their underlying concepts compared to related concepts in Tantric Buddhism and Zen-Buddhism. The conclusion is drawn that the biblical concepts are transposed in the poetry in order to create Buddhist concepts of life and death, time and a form of self-denial. De-sacralisation of the Christian. concepts is inevitable in this creative process. However, the primary intention of the author is not de-sacralisation, but the implementation 'of the Buddhist philosophy of life in which everything is experienced as "totally one". A comparison between the reconstructed intended reader of Breytenbach's poetry and elements of the Afrikaans reading public suggests that political comment on segregated South African society is intended. Breytenbach's poetry is compared to canonized Afrikaans poetry with respect to Buddhist influence, national protest, aspiration to holiness and transposed biblical concepts. The conclusion is that his poetry is highly innovative in these respects. In the broader spectrum of South African literature his poetry is compared, with reference to transposed biblical concepts and national protest, to the poetry of Black poets writing in English, and (where material is available) to those writing in Afrikaans. The conclusion is that Breytenbach's poetry is strongly linked to this poetry. However, the complexity of Breytenbach's poetry, and the advanced aesthetic level and linguistic code required of the intended reader determine his placing within the canon of Afrikaans poetry.
- Full Text:
- Date Issued: 1988
Extractives from six species of Lamiaceae
- Davies-Coleman, Michael Trevor
- Authors: Davies-Coleman, Michael Trevor
- Date: 1988
- Subjects: Lamiaceae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4532 , http://hdl.handle.net/10962/d1016235
- Description: In continuation of the phytochemical studies of plants belonging to the Lamiaceae (formerly Labiatae) the acetone extractives of six Southern African species from this family have been examined. The genus Syncolostemon has not been investigated before and a new 6- substituted-5 ,6-dihydro-a-pyrone , synrotolide was isolated from S. rotundifolius. The structure of synrotolide was fully elucidated as 6fixii [3'R, 61S-(diacetyloxy)-4 1R, 5 1 8-(dihydroxy)-1~-hepteny~ -5,6-dihydro-2H-pyran- 2-one. Oleanolic acid is the major component of both~ rotundifolius and S. densifloris. The flavonol quercetin was isolated from S. densifloris as its 3, 3', 4' , 7 tetramethyl ether. A further 6-substituted-5,6-dihydro-a-pyrone, boronolide, was obtained from Tetradenia barberae. The structure of boronolide was known but the absolute stereochemistry was unassigned. Chemical degradation established the total structure of this compound as 6R- [1 'R, 2'R, 3's -(trisacetyloxy)heptyl] -5,6-dihydro-2H-pyran-2-one. The chemistry of naturally occuring 6-substituted-5,6-dihydro-apyrones has not as such been previously reviewed and a comprehensive review covering the literature up to June 1987 is presented here. Three known labdane diterpenoids nepetaefuran, hispanalone and dubiin were iso lated from Leonotis nepetaefolia, Ballota africana and L. ocymifolia var. ocymifolia (formerly~ dubia). Both~ nepetaefolia and L. dubia have been examined before. An X-ray analysis of saponified dubiin and a circular dichroism study of 6-deacetyldehydrodubiin and related compounds corroborated the structure of dubiin as 48, 5R, 6R, 8R, 9R, 10R-[6-acetoxy-15,16-epoxy-9-hydroxylabda-13 (16), 14-dien-19, 20- olactoneJ. The chemotaxonomic relationships of the genera Ballota and Leonotis are discussed.
- Full Text:
- Date Issued: 1988
- Authors: Davies-Coleman, Michael Trevor
- Date: 1988
- Subjects: Lamiaceae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4532 , http://hdl.handle.net/10962/d1016235
- Description: In continuation of the phytochemical studies of plants belonging to the Lamiaceae (formerly Labiatae) the acetone extractives of six Southern African species from this family have been examined. The genus Syncolostemon has not been investigated before and a new 6- substituted-5 ,6-dihydro-a-pyrone , synrotolide was isolated from S. rotundifolius. The structure of synrotolide was fully elucidated as 6fixii [3'R, 61S-(diacetyloxy)-4 1R, 5 1 8-(dihydroxy)-1~-hepteny~ -5,6-dihydro-2H-pyran- 2-one. Oleanolic acid is the major component of both~ rotundifolius and S. densifloris. The flavonol quercetin was isolated from S. densifloris as its 3, 3', 4' , 7 tetramethyl ether. A further 6-substituted-5,6-dihydro-a-pyrone, boronolide, was obtained from Tetradenia barberae. The structure of boronolide was known but the absolute stereochemistry was unassigned. Chemical degradation established the total structure of this compound as 6R- [1 'R, 2'R, 3's -(trisacetyloxy)heptyl] -5,6-dihydro-2H-pyran-2-one. The chemistry of naturally occuring 6-substituted-5,6-dihydro-apyrones has not as such been previously reviewed and a comprehensive review covering the literature up to June 1987 is presented here. Three known labdane diterpenoids nepetaefuran, hispanalone and dubiin were iso lated from Leonotis nepetaefolia, Ballota africana and L. ocymifolia var. ocymifolia (formerly~ dubia). Both~ nepetaefolia and L. dubia have been examined before. An X-ray analysis of saponified dubiin and a circular dichroism study of 6-deacetyldehydrodubiin and related compounds corroborated the structure of dubiin as 48, 5R, 6R, 8R, 9R, 10R-[6-acetoxy-15,16-epoxy-9-hydroxylabda-13 (16), 14-dien-19, 20- olactoneJ. The chemotaxonomic relationships of the genera Ballota and Leonotis are discussed.
- Full Text:
- Date Issued: 1988
Life history changes of two reef fish species in exploited and unexploited marine environments in South Africa
- Authors: Buxton, Colin David
- Date: 1988
- Subjects: Reef fishes -- Africa, Southern Chrysoblephus laticeps Chrysoblephus cristiceps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5189 , http://hdl.handle.net/10962/d1001965
- Description: A detailed investigation into the life histories of Chrysoblephus laticeps and c. cristiceps in exploited and unexploited marine environments on the south-east coast of southern Africa is presented. The study provided information necessary for the evaluation of marine reserves as a management option for these and similar reef species. Visual underwater assessments showed a clear spatial separation between adults and juveniles of both species, suggesting a recruitment of juveniles into shallow water followed by a gradual outward migration into deeper water with age. Denslty estlmates of C. laticeps in the Noordhoek (0.0064 fish/m²) and Tsitslkamma (0.0254 fish/m²) areas were significantly different and were attributed to exploitation. Within area differences in density were also significantly correlated with temperature) depth and substratum relief. Similar comparisons for C. cristiceps were not possible because these fish shied away from divers. Habitat preferences were mirrored in the diets of both species which fed on a wide variety of reef associated benthic animals. Size of prey appeared to be gape limited, only larger fish being able to manipulate prey. Quantitative differences between the diets of fish sampled in different areas were a reflection of differences in available prey and not related to the relative density of predators. The dietary characteristics recorded in these fish were typical of search hunters. An age and growth study based on the examination of sectioned otoliths showed that both species were slow growing and long lived. Maximum recorded ages were 18 and 22 years for C. laticeps and C. cristiceps respectively. Growth rates in exploited and unexploited areas were not significantly different although there was an indication that growth was slower in the exploited areas for C. cristiceps. Several inconsistencies in otolith interpretation and terminology were evaluated. Contrary to other South African studies the results suggested that somatic growth was fastest just after spawning. This coincided with the winter months and was reflected by the deposition of a hyaline zone in the otolith. Two independent estimates, the Pauli derivation and visually assessed length frequency analysis, produced the same value for total mortality of C. laticeps in the Tsitsikamma area (0.2). This result, together with a significant difference in the rate of fishing mortality at different areas along the coast suggested that the populations sampled were discrete and supported the postulate that both species were sedentary. Further support was obtained from a mark-recapture study. Although sample numbers were low the results showed no evidence of large scale migratory patterns in these fish. An investigation of the reproductive biology of both fish showed that they were protogynous hermaphrodites, all males being derived from females with no evidence for polyandry. Males were shown to be capable of mating with a number of females and this, together with monandry, monochromatism and a small testis size, suggested a polygynous mating system in both species. Observations of the courtship behaviour in captive c. laticeps also supported polygyny. A significant difference in the mean size at sex reversal between unexploited and exploited populations supported the postulate that sex reversal was independent of the size or age of the animal. The size at which sex reversal occurred appeared to be dependent on sex ratio. A detailed yield per recruit analysis of the response of the population to different levels of fishing mortality and size at recruitment (t [subscript]r), showed that sex reversing species were particularly vulnerable to over fishing. This was due to a dramatic decline in the number of surviving individuals past t[subscript]r which resulted in a skewing of the sex ratio towards females. Evidence is presented to show that current legislation is inadequately protecting the spawner stock of both species. In conclusion it is shown that longevity, sex reversal, restricted movements and the occupation of a demersal habitat make these species particularly vulnerable to over exploitation in a size- selective fishery. The sustained yield in the linefishery is suggested to be a result of distant recruitment from relatively unexploited populations rather than the adequacy of current conservation measures. The need to protect the spawner stock is emphasised and the use of marine reserves as an additional protection for sedentary reef-dwelling species is therefore advocated.
- Full Text:
- Date Issued: 1988
- Authors: Buxton, Colin David
- Date: 1988
- Subjects: Reef fishes -- Africa, Southern Chrysoblephus laticeps Chrysoblephus cristiceps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5189 , http://hdl.handle.net/10962/d1001965
- Description: A detailed investigation into the life histories of Chrysoblephus laticeps and c. cristiceps in exploited and unexploited marine environments on the south-east coast of southern Africa is presented. The study provided information necessary for the evaluation of marine reserves as a management option for these and similar reef species. Visual underwater assessments showed a clear spatial separation between adults and juveniles of both species, suggesting a recruitment of juveniles into shallow water followed by a gradual outward migration into deeper water with age. Denslty estlmates of C. laticeps in the Noordhoek (0.0064 fish/m²) and Tsitslkamma (0.0254 fish/m²) areas were significantly different and were attributed to exploitation. Within area differences in density were also significantly correlated with temperature) depth and substratum relief. Similar comparisons for C. cristiceps were not possible because these fish shied away from divers. Habitat preferences were mirrored in the diets of both species which fed on a wide variety of reef associated benthic animals. Size of prey appeared to be gape limited, only larger fish being able to manipulate prey. Quantitative differences between the diets of fish sampled in different areas were a reflection of differences in available prey and not related to the relative density of predators. The dietary characteristics recorded in these fish were typical of search hunters. An age and growth study based on the examination of sectioned otoliths showed that both species were slow growing and long lived. Maximum recorded ages were 18 and 22 years for C. laticeps and C. cristiceps respectively. Growth rates in exploited and unexploited areas were not significantly different although there was an indication that growth was slower in the exploited areas for C. cristiceps. Several inconsistencies in otolith interpretation and terminology were evaluated. Contrary to other South African studies the results suggested that somatic growth was fastest just after spawning. This coincided with the winter months and was reflected by the deposition of a hyaline zone in the otolith. Two independent estimates, the Pauli derivation and visually assessed length frequency analysis, produced the same value for total mortality of C. laticeps in the Tsitsikamma area (0.2). This result, together with a significant difference in the rate of fishing mortality at different areas along the coast suggested that the populations sampled were discrete and supported the postulate that both species were sedentary. Further support was obtained from a mark-recapture study. Although sample numbers were low the results showed no evidence of large scale migratory patterns in these fish. An investigation of the reproductive biology of both fish showed that they were protogynous hermaphrodites, all males being derived from females with no evidence for polyandry. Males were shown to be capable of mating with a number of females and this, together with monandry, monochromatism and a small testis size, suggested a polygynous mating system in both species. Observations of the courtship behaviour in captive c. laticeps also supported polygyny. A significant difference in the mean size at sex reversal between unexploited and exploited populations supported the postulate that sex reversal was independent of the size or age of the animal. The size at which sex reversal occurred appeared to be dependent on sex ratio. A detailed yield per recruit analysis of the response of the population to different levels of fishing mortality and size at recruitment (t [subscript]r), showed that sex reversing species were particularly vulnerable to over fishing. This was due to a dramatic decline in the number of surviving individuals past t[subscript]r which resulted in a skewing of the sex ratio towards females. Evidence is presented to show that current legislation is inadequately protecting the spawner stock of both species. In conclusion it is shown that longevity, sex reversal, restricted movements and the occupation of a demersal habitat make these species particularly vulnerable to over exploitation in a size- selective fishery. The sustained yield in the linefishery is suggested to be a result of distant recruitment from relatively unexploited populations rather than the adequacy of current conservation measures. The need to protect the spawner stock is emphasised and the use of marine reserves as an additional protection for sedentary reef-dwelling species is therefore advocated.
- Full Text:
- Date Issued: 1988
Mathematics and physical science choices made by pupils in selected Eastern Cape high schools: an investigation into the factors influencing the different choice patterns of boys and girls
- Authors: Ilsley, Jeffrey Robert
- Date: 1988
- Subjects: Sex differences in education -- South Africa Education, Secondary -- Curricula -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa Physical sciences -- Study and teaching (Secondary) -- South Africa Mathematics -- Study and teaching -- Psychological aspects Physical sciences -- Study and teaching -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1869 , http://hdl.handle.net/10962/d1004750
- Description: The disparate numbers of boys and girls who elect to continue with mathemalics and/or physical science in the higher slandards of the school system has recently attracted much research atlention and the complexity of the interrelaledness of causal factors has become obvious. The broad aim of the study was to investigale the significant drop-out rate of girls at the end of the junior secondary phase of education (approximate age of fourteen lo fifteen). This was to be carried out for mathematics and physical science and undertaken using a cross-sectional and a longitudinal study. The cross-sectional study entailed administering mathematics and physical science attitude questionnaires to 3531 standard six, seven and eight pupils from 4 co-educational, 2 allgirls' and 2 all-boys' schools, from middle and upper socioeconomic communities with similar language and cultural backgrounds . The longitudinal study involved pupils from two coeducational schools and one all-girls' school. It was a progressively-focused study starting with questionnaires administered to 358 standard six girls and boys, narrowing down to questionnaires and interviews used with 50 girls and 28 boys in standard seven and finally to interviews with 10 girls from standard eight. The parents of these ten girls were interviewed at the end of the study. The attilude questionnaires yielded strong sex differences which favoured the boys in both subjects for all the attitudes measured and also pointed to a progressive deterioralion of altitudes over the three-standard span. They also established significant differences in attitudes which favoured the pupils from Single-sex schools. It was further concluded that the girls were more strongly guided by their attitudes when making their subject-choice decisions. In the longitudinal study, reasons were suggested for pupils either taking or dropping mathematics and physical science. The introduction of algebra in the first year of high school presented a problem to pupils. In physical science, electricity was singled out as giving the subject a male bias. Socialization influences in the home were the main issue dealt with from the parent interviews . Sex-roles and stereotypes were dealt with in depth. Recommendations were made involving classroom strategies, curriculum possibilities, school policies and further research
- Full Text:
- Date Issued: 1988
- Authors: Ilsley, Jeffrey Robert
- Date: 1988
- Subjects: Sex differences in education -- South Africa Education, Secondary -- Curricula -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa Physical sciences -- Study and teaching (Secondary) -- South Africa Mathematics -- Study and teaching -- Psychological aspects Physical sciences -- Study and teaching -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1869 , http://hdl.handle.net/10962/d1004750
- Description: The disparate numbers of boys and girls who elect to continue with mathemalics and/or physical science in the higher slandards of the school system has recently attracted much research atlention and the complexity of the interrelaledness of causal factors has become obvious. The broad aim of the study was to investigale the significant drop-out rate of girls at the end of the junior secondary phase of education (approximate age of fourteen lo fifteen). This was to be carried out for mathematics and physical science and undertaken using a cross-sectional and a longitudinal study. The cross-sectional study entailed administering mathematics and physical science attitude questionnaires to 3531 standard six, seven and eight pupils from 4 co-educational, 2 allgirls' and 2 all-boys' schools, from middle and upper socioeconomic communities with similar language and cultural backgrounds . The longitudinal study involved pupils from two coeducational schools and one all-girls' school. It was a progressively-focused study starting with questionnaires administered to 358 standard six girls and boys, narrowing down to questionnaires and interviews used with 50 girls and 28 boys in standard seven and finally to interviews with 10 girls from standard eight. The parents of these ten girls were interviewed at the end of the study. The attilude questionnaires yielded strong sex differences which favoured the boys in both subjects for all the attitudes measured and also pointed to a progressive deterioralion of altitudes over the three-standard span. They also established significant differences in attitudes which favoured the pupils from Single-sex schools. It was further concluded that the girls were more strongly guided by their attitudes when making their subject-choice decisions. In the longitudinal study, reasons were suggested for pupils either taking or dropping mathematics and physical science. The introduction of algebra in the first year of high school presented a problem to pupils. In physical science, electricity was singled out as giving the subject a male bias. Socialization influences in the home were the main issue dealt with from the parent interviews . Sex-roles and stereotypes were dealt with in depth. Recommendations were made involving classroom strategies, curriculum possibilities, school policies and further research
- Full Text:
- Date Issued: 1988
Structural studies on some capsular antigens from escherichia coli and klebsiella
- Authors: Anderson, Andrew Nixon
- Date: 1988
- Subjects: Escherichia , Klebsiella , Antigens
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3730 , http://hdl.handle.net/10962/d1001469
- Description: A review of the structural studies of bacterial capsular polysaccharides (K-antigens) from Escherichia coli and Klebsiella, and of the trends in modern chemical and instrumental techniques available for the analysis of carbohydrate material is presented. The structural elucidations of the capsular polysaccharides from E. coli K37 and K55, and Klebsiella K39 are reported with comments on the novelty and possible immunological significance of the structures. The usefulness of the bacteriophage degradation technique has been emphasized using the polysaccharides from E. coli K55, and Klebsiella K30 and K39 to demonstrate the scope of the reaction
- Full Text:
- Date Issued: 1988
- Authors: Anderson, Andrew Nixon
- Date: 1988
- Subjects: Escherichia , Klebsiella , Antigens
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3730 , http://hdl.handle.net/10962/d1001469
- Description: A review of the structural studies of bacterial capsular polysaccharides (K-antigens) from Escherichia coli and Klebsiella, and of the trends in modern chemical and instrumental techniques available for the analysis of carbohydrate material is presented. The structural elucidations of the capsular polysaccharides from E. coli K37 and K55, and Klebsiella K39 are reported with comments on the novelty and possible immunological significance of the structures. The usefulness of the bacteriophage degradation technique has been emphasized using the polysaccharides from E. coli K55, and Klebsiella K30 and K39 to demonstrate the scope of the reaction
- Full Text:
- Date Issued: 1988
Studies on zooplankton feeding ecology and resource utilization in a sub-tropical hypertrophic impoundment (Hartbeespoort Dam, South Africa)
- Authors: Jarvis, Andrew Charles
- Date: 1988
- Subjects: Freshwater zooplankton -- Ecology -- South Africa Freshwater zooplankton -- Tropics -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5624 , http://hdl.handle.net/10962/d1004600
- Description: Various aspects of the feeding ecology of zooplankton are described for hypertrophic Hartbeespoort Dam, where the phytoplankton is dominated by the cyanophyte Microcystis. The study considers zooplankton succession, community grazing rates, and speciesspecific filtration rates on Microaystis colonies and natural bacterioplankton. Seasonal abundance of the main herbivorous zooplankton between 1981 and 1986 is described both in respect of biomass and specific densities. In situ community grazing rates were measured from January 1983 to March 1985 using 14C-Iabelled Chlorella . Zooplankton succession and community grazing rates are examined in relation to food quantity and quality. Experiments measuring species-specific filtration rates on labelled Chlorella and Microcystis colony fractions revealed low filtration rates for small-bodied cladoceran species on cyanophyte colonies. Daphnia fed significantly on Microcystis colonies up to 60-100 ).μm but Daphnia filtration rates on Chlorella were suppressed by ~707. during the mid-summer increase in Microcystis abundance. Filtration rates of small cladoceran species were not suppressed by MicpocystisJ which was not an important food resource . Cladoceran filtration rate:body length models were developed for Chlorella and Microcystis colony fractions as food. Multiple regression models explained variance in filtration rates on these foods as a function of body length, food type and size, grazer species and temperature (in order of significance). Inclusion of food quality factors such as cyanophyte colony size seems justified in models of plankton feeding in eutrophic or hypertrophic lakes. Methods for in situ measurement of zooplankton filtration rates on 'H-thymidine-Iabelled natural bacteria were improved for use under hypertrophic conditions, and associated isotope-adsorption errors were measured. Community, species-specific and length-specific filtration rates on bacterioplankton were measured (late-spring to late-summer 1986-87) . Ceriodaphnia exhibited no preference for bacteria or Chlorella. Other cladocerans preferred the algal food . Algal/bacterial selectivity coefficients of the zooplankton community revealed an increased algal preference following the mid-summer shift to phytoplankton dominance by largely inedible Microcystis. This implies that bacterioplankton is not an important food resource for the summer cladoceran community. Estimates of the contribution of bacterial carbon to the daily zooplankton carbon requirements are low. The implications of all results are discussed in relation to seasonal succession, the clear-water phase', and biomanipulation in this hypertrophic reservoir.
- Full Text:
- Date Issued: 1988
- Authors: Jarvis, Andrew Charles
- Date: 1988
- Subjects: Freshwater zooplankton -- Ecology -- South Africa Freshwater zooplankton -- Tropics -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5624 , http://hdl.handle.net/10962/d1004600
- Description: Various aspects of the feeding ecology of zooplankton are described for hypertrophic Hartbeespoort Dam, where the phytoplankton is dominated by the cyanophyte Microcystis. The study considers zooplankton succession, community grazing rates, and speciesspecific filtration rates on Microaystis colonies and natural bacterioplankton. Seasonal abundance of the main herbivorous zooplankton between 1981 and 1986 is described both in respect of biomass and specific densities. In situ community grazing rates were measured from January 1983 to March 1985 using 14C-Iabelled Chlorella . Zooplankton succession and community grazing rates are examined in relation to food quantity and quality. Experiments measuring species-specific filtration rates on labelled Chlorella and Microcystis colony fractions revealed low filtration rates for small-bodied cladoceran species on cyanophyte colonies. Daphnia fed significantly on Microcystis colonies up to 60-100 ).μm but Daphnia filtration rates on Chlorella were suppressed by ~707. during the mid-summer increase in Microcystis abundance. Filtration rates of small cladoceran species were not suppressed by MicpocystisJ which was not an important food resource . Cladoceran filtration rate:body length models were developed for Chlorella and Microcystis colony fractions as food. Multiple regression models explained variance in filtration rates on these foods as a function of body length, food type and size, grazer species and temperature (in order of significance). Inclusion of food quality factors such as cyanophyte colony size seems justified in models of plankton feeding in eutrophic or hypertrophic lakes. Methods for in situ measurement of zooplankton filtration rates on 'H-thymidine-Iabelled natural bacteria were improved for use under hypertrophic conditions, and associated isotope-adsorption errors were measured. Community, species-specific and length-specific filtration rates on bacterioplankton were measured (late-spring to late-summer 1986-87) . Ceriodaphnia exhibited no preference for bacteria or Chlorella. Other cladocerans preferred the algal food . Algal/bacterial selectivity coefficients of the zooplankton community revealed an increased algal preference following the mid-summer shift to phytoplankton dominance by largely inedible Microcystis. This implies that bacterioplankton is not an important food resource for the summer cladoceran community. Estimates of the contribution of bacterial carbon to the daily zooplankton carbon requirements are low. The implications of all results are discussed in relation to seasonal succession, the clear-water phase', and biomanipulation in this hypertrophic reservoir.
- Full Text:
- Date Issued: 1988