A comparative study of acute responses to running in elite black and white marathon athletes
- Authors: Bosch, Andrew Norman
- Date: 1985
- Subjects: Athletics , Sports -- Physiological aspects , Running races , Marathon running , Marathon running -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5099 , http://hdl.handle.net/10962/d1001839 , Athletics , Sports -- Physiological aspects , Running races , Marathon running , Marathon running -- Physiological aspects
- Description: Experienced male marathon runners, 9 black and 10 white, with marathon times of 2 hours 45 minutes or faster, acted as subjects for the study, the purpose of which was to determine whether black runners are better suited to marathon running than whites. Body composition was determined by anthropometry. Maximal oxygen uptake (VO₂ max) and other physiological variables were measured during a continuous, speed-incremented treadmill protocol using a computer-aided data acquisition system. Subjects also ran a simulated marathon at 92.5% of the running speed at which the ventilatory threshold (VT) occurred. Physiological, gait and RPE variables were measured at 10 minute intervals during the marathon. Major findings are detailed below:- The VO₂, max averaged 60.4 ∓ 6.5 and 63.2 ∓ 2.9 mI. kg⁻¹.min⁻¹ in the black and white runners respectively and was highly correlated with best marathon race time (r = 0.86 and 0.85 respectively) and VT (r = 0.84 and 0.60 respectively) (p < 0.05). No significant differences existed between the groups in submaximal oxygen uptake (VO₂,) or % VO₂ max utilised at 16 km.hr⁻¹, but the estimated % VO₂ max utilised during a marathon race was higher in the black (89.0 ∓ 5.5%) than the white runners (81. 5 ∓ 3.1%) {p .( 0.05). The % VO₂ max utilised at 16 km.hr⁻¹ (84.8 ∓ 9.1 and 78.6 ∓ 5.8% in the black and white runners respectively) was significantly correlated with the % VO₂, max utilised while racing in the white (81.5 ∓ 3.1%) (r = 0.70) (p < 0.05), but not the black runners (89.0 ∓ 5.5%). The VT occurred at 82.7 ∓ 7.7 and 75.6 :∓ 6.2% VO₂; max in the black and white groups respectively (p < 0.05). Post-marathon blood lactic acid levels were lower in the black (1.30 ∓ 0.26 mmo1.l⁻¹) than the white runners (1.59 ∓ 0.20 mmol.l⁻¹). The respiratory exchange ratio (R) was higher in the blacks than whites when running at 16 km.hr ⁻¹ (1.03 ∓ 0.07 and 0.98 ∓ 0.03 respectively) and during the marathon (p < 0.05). There was no significant difference in pulmonary minute ventilation (Vı) between the groups, but breathing frequency (f) was higher in the black (59 ∓ 12 breaths.min⁻¹) than the white runners (45 ∓ 8 breaths. min⁻¹ ) and tidal volume (V⊤) lower in the black ( 1.33 ∓ 0.16 l.breath⁻¹) than the white runners (1.75 ∓ 0.36 I.breath⁻¹) during submaximal running at 16 km. hr⁻¹ (p < 0.05). The same trend was observed during the marathon run. During the time-course of the marathon f increased and V⊤ decreased In both groups (p < 0.05). Stroke volume decreased and heart rate increased In both groups during the time-course of the marathon (p< 0.05). Cardiac output was therefore maintained. Thermal responses were similar in the two groups. A significant increase in rectal temperature coincided with a decrease in skin temperature and may have been related to an increase in f (r = 0.86 and 0.67 in the blacks and whites respectively), H/R (r = 0.70 and 0.67 respectively) and "local" (leg) RPE (r = 0.84 and 0.82 respectively). It was concluded that black runners were able to run marathon races at a higher % VO₂ more than whites due to the blacks having lower blood lactic acid levels when running at a similar % VO₂ max. Given similar maximal oxygen uptakes, this would enable blacks to run faster. Cardiopulmonary adjustments occur during the time-course of a marathon which maintains Q and Vı
- Full Text:
- Date Issued: 1985
- Authors: Bosch, Andrew Norman
- Date: 1985
- Subjects: Athletics , Sports -- Physiological aspects , Running races , Marathon running , Marathon running -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5099 , http://hdl.handle.net/10962/d1001839 , Athletics , Sports -- Physiological aspects , Running races , Marathon running , Marathon running -- Physiological aspects
- Description: Experienced male marathon runners, 9 black and 10 white, with marathon times of 2 hours 45 minutes or faster, acted as subjects for the study, the purpose of which was to determine whether black runners are better suited to marathon running than whites. Body composition was determined by anthropometry. Maximal oxygen uptake (VO₂ max) and other physiological variables were measured during a continuous, speed-incremented treadmill protocol using a computer-aided data acquisition system. Subjects also ran a simulated marathon at 92.5% of the running speed at which the ventilatory threshold (VT) occurred. Physiological, gait and RPE variables were measured at 10 minute intervals during the marathon. Major findings are detailed below:- The VO₂, max averaged 60.4 ∓ 6.5 and 63.2 ∓ 2.9 mI. kg⁻¹.min⁻¹ in the black and white runners respectively and was highly correlated with best marathon race time (r = 0.86 and 0.85 respectively) and VT (r = 0.84 and 0.60 respectively) (p < 0.05). No significant differences existed between the groups in submaximal oxygen uptake (VO₂,) or % VO₂ max utilised at 16 km.hr⁻¹, but the estimated % VO₂ max utilised during a marathon race was higher in the black (89.0 ∓ 5.5%) than the white runners (81. 5 ∓ 3.1%) {p .( 0.05). The % VO₂ max utilised at 16 km.hr⁻¹ (84.8 ∓ 9.1 and 78.6 ∓ 5.8% in the black and white runners respectively) was significantly correlated with the % VO₂, max utilised while racing in the white (81.5 ∓ 3.1%) (r = 0.70) (p < 0.05), but not the black runners (89.0 ∓ 5.5%). The VT occurred at 82.7 ∓ 7.7 and 75.6 :∓ 6.2% VO₂; max in the black and white groups respectively (p < 0.05). Post-marathon blood lactic acid levels were lower in the black (1.30 ∓ 0.26 mmo1.l⁻¹) than the white runners (1.59 ∓ 0.20 mmol.l⁻¹). The respiratory exchange ratio (R) was higher in the blacks than whites when running at 16 km.hr ⁻¹ (1.03 ∓ 0.07 and 0.98 ∓ 0.03 respectively) and during the marathon (p < 0.05). There was no significant difference in pulmonary minute ventilation (Vı) between the groups, but breathing frequency (f) was higher in the black (59 ∓ 12 breaths.min⁻¹) than the white runners (45 ∓ 8 breaths. min⁻¹ ) and tidal volume (V⊤) lower in the black ( 1.33 ∓ 0.16 l.breath⁻¹) than the white runners (1.75 ∓ 0.36 I.breath⁻¹) during submaximal running at 16 km. hr⁻¹ (p < 0.05). The same trend was observed during the marathon run. During the time-course of the marathon f increased and V⊤ decreased In both groups (p < 0.05). Stroke volume decreased and heart rate increased In both groups during the time-course of the marathon (p< 0.05). Cardiac output was therefore maintained. Thermal responses were similar in the two groups. A significant increase in rectal temperature coincided with a decrease in skin temperature and may have been related to an increase in f (r = 0.86 and 0.67 in the blacks and whites respectively), H/R (r = 0.70 and 0.67 respectively) and "local" (leg) RPE (r = 0.84 and 0.82 respectively). It was concluded that black runners were able to run marathon races at a higher % VO₂ more than whites due to the blacks having lower blood lactic acid levels when running at a similar % VO₂ max. Given similar maximal oxygen uptakes, this would enable blacks to run faster. Cardiopulmonary adjustments occur during the time-course of a marathon which maintains Q and Vı
- Full Text:
- Date Issued: 1985
A contribution to the oceanology of the Prince Edward Islands
- Authors: Parker, Llewellyn Derek
- Date: 1985
- Subjects: Oceanography -- Prince Edward Islands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5605 , http://hdl.handle.net/10962/d1002055
- Description: While the terrestrial ecosystem of the Prince Edward Island Group has been subject to intensive research, the marine ecosystem has to a large extent been neglected. This together with the possible existence of an "island effect" at these islands, as was first proposed after the visit to these islands of the French vessel Marion Dufresne, led to the initiation of a programme to determine the distribution of standing stocks and the productivity of phytoplankton and zooplankton in the neritic seas of these islands. To do this and before a detailed biological survey could be attempted, it was first necessary to define the physical and chemical properties of the circuminsular waters. This dissertation discusses the results of several surveys to these islands in the light of a possible "island effect" and comments upon processes likely to influence such an effect
- Full Text:
- Date Issued: 1985
- Authors: Parker, Llewellyn Derek
- Date: 1985
- Subjects: Oceanography -- Prince Edward Islands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5605 , http://hdl.handle.net/10962/d1002055
- Description: While the terrestrial ecosystem of the Prince Edward Island Group has been subject to intensive research, the marine ecosystem has to a large extent been neglected. This together with the possible existence of an "island effect" at these islands, as was first proposed after the visit to these islands of the French vessel Marion Dufresne, led to the initiation of a programme to determine the distribution of standing stocks and the productivity of phytoplankton and zooplankton in the neritic seas of these islands. To do this and before a detailed biological survey could be attempted, it was first necessary to define the physical and chemical properties of the circuminsular waters. This dissertation discusses the results of several surveys to these islands in the light of a possible "island effect" and comments upon processes likely to influence such an effect
- Full Text:
- Date Issued: 1985
A geographical analysis of farming in East Griqualand
- Authors: Leslie, Kathryn Ann
- Date: 1985
- Subjects: Agriculture -- Griqualand East (South Africa) , Rural development -- Griqualand East (South Africa) , Agricultural deography -- Griqualand East (South Africa) , Geography -- Methodology , Infrastructure (Economics) -- Griqualand East (South Africa)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4860 , http://hdl.handle.net/10962/d1005857 , Agriculture -- Griqualand East (South Africa) , Rural development -- Griqualand East (South Africa) , Agricultural deography -- Griqualand East (South Africa) , Geography -- Methodology , Infrastructure (Economics) -- Griqualand East (South Africa)
- Description: From Preface: The study focusses on spatial aspects of farming and particularly how di stance from marketing centres influences farming activity. However, not all aspects of farming activity could be given close attention due to the limited time and funds available and it was decided to isolate two aspects of farming activity for detailed study, namely, farm size and intensity. Other variables, such as land-use, are looked at in relation to the two main variables. Although East Griqualand is the general area selected for study, for practical purposes it was decided to select areas within East Griqualand for an in-depth study. As the study focusses on the influence of distance from marketing centres on farming activity, it was decided to select marketing centres in East Griqualand around which farming takes place. There are six of these centres in East Griqualand, that is, Kokstad, Matatiele, Cedarville, Franklin, Swartberg and New Amalfi. Two marketing centres, Cedarville and Swartberg, were selected and the farms served by these centres became the two sub-areas in which the research was conducted. The selection of the marketing centres and the justification for this selection is discussed in Chapter Four. A problem arose when calculating the distance from the farming unit to the marketing centre where a single set of books is kept even though the farming unit does not consist of one contiguous area. It was, however, found that all farmers conduct farming operations from a central farm, usually that on which they reside and on which farming implements and other farming requirements are stored. The distance was therefore calculated from the farm gate of the farm from which farming operations are controlled. The general study area is show in Figure 6. However, it was difficult to delimit the exact study area on the map as many of the farm boundaries were imperfectly known by farmers and were considered confidential information by local agricultural officials. The two sub-areas consist of the areas surrounding the marketing centres of Cedarville and Swartberg respectively. As a study of this nature has not previously been conducted in East Griqualand, it was decided that the study should constitute a pilot survey. As such, the study is a preliminary survey aimed at identifying general trends of the relationship between distance to marketing centres, farm size and intensity of fanning in the selected areas. The study could therefore be used to provide pointers for further research and act as a basis for a more comprehensive study of the same nature in East Griqualand.
- Full Text:
- Date Issued: 1985
- Authors: Leslie, Kathryn Ann
- Date: 1985
- Subjects: Agriculture -- Griqualand East (South Africa) , Rural development -- Griqualand East (South Africa) , Agricultural deography -- Griqualand East (South Africa) , Geography -- Methodology , Infrastructure (Economics) -- Griqualand East (South Africa)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4860 , http://hdl.handle.net/10962/d1005857 , Agriculture -- Griqualand East (South Africa) , Rural development -- Griqualand East (South Africa) , Agricultural deography -- Griqualand East (South Africa) , Geography -- Methodology , Infrastructure (Economics) -- Griqualand East (South Africa)
- Description: From Preface: The study focusses on spatial aspects of farming and particularly how di stance from marketing centres influences farming activity. However, not all aspects of farming activity could be given close attention due to the limited time and funds available and it was decided to isolate two aspects of farming activity for detailed study, namely, farm size and intensity. Other variables, such as land-use, are looked at in relation to the two main variables. Although East Griqualand is the general area selected for study, for practical purposes it was decided to select areas within East Griqualand for an in-depth study. As the study focusses on the influence of distance from marketing centres on farming activity, it was decided to select marketing centres in East Griqualand around which farming takes place. There are six of these centres in East Griqualand, that is, Kokstad, Matatiele, Cedarville, Franklin, Swartberg and New Amalfi. Two marketing centres, Cedarville and Swartberg, were selected and the farms served by these centres became the two sub-areas in which the research was conducted. The selection of the marketing centres and the justification for this selection is discussed in Chapter Four. A problem arose when calculating the distance from the farming unit to the marketing centre where a single set of books is kept even though the farming unit does not consist of one contiguous area. It was, however, found that all farmers conduct farming operations from a central farm, usually that on which they reside and on which farming implements and other farming requirements are stored. The distance was therefore calculated from the farm gate of the farm from which farming operations are controlled. The general study area is show in Figure 6. However, it was difficult to delimit the exact study area on the map as many of the farm boundaries were imperfectly known by farmers and were considered confidential information by local agricultural officials. The two sub-areas consist of the areas surrounding the marketing centres of Cedarville and Swartberg respectively. As a study of this nature has not previously been conducted in East Griqualand, it was decided that the study should constitute a pilot survey. As such, the study is a preliminary survey aimed at identifying general trends of the relationship between distance to marketing centres, farm size and intensity of fanning in the selected areas. The study could therefore be used to provide pointers for further research and act as a basis for a more comprehensive study of the same nature in East Griqualand.
- Full Text:
- Date Issued: 1985
A hydrogeological assessment of the Uitenhage-Coega artesian system
- Authors: Venables, Anthony John
- Date: 1985
- Subjects: Hydrogeology -- South Africa Aquifers -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4808 , http://hdl.handle.net/10962/d1003815
- Description: The Uitenhage artesian aquifer north-west of Port Elizabeth in South Africa, is one of the few artesian groundwater systems in Southern Africa. The Uitenhage - Coega, and Kruis River areas, are the most important portions of the Uitenhage Artesian System in terms of water abstraction and water use. This study concentrates on the Uitenhage - Coega area and in particular, on the Coega Ridge where the Table Mountain Sandstone (TNS) aquifer occurs at relatively shallow depths. The investigation is aimed at assessing the geological, hydrogeological and hydrochemical characteristics of the HIS and any other aquifers present, with the object of providing quantitative data for use in future decisions on the water resource management of the area. In order to achieve these objectives, field work, involving a hydrocensus, geological mapping, geophysical exploration, drilling, aquifer testing and hydrochemical sampling was carried out. Analysis of these data provided information on the extent of the aquifers, their hydrogeological characteristics and the chemical nature of the various groundwater types.
- Full Text:
- Date Issued: 1985
- Authors: Venables, Anthony John
- Date: 1985
- Subjects: Hydrogeology -- South Africa Aquifers -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4808 , http://hdl.handle.net/10962/d1003815
- Description: The Uitenhage artesian aquifer north-west of Port Elizabeth in South Africa, is one of the few artesian groundwater systems in Southern Africa. The Uitenhage - Coega, and Kruis River areas, are the most important portions of the Uitenhage Artesian System in terms of water abstraction and water use. This study concentrates on the Uitenhage - Coega area and in particular, on the Coega Ridge where the Table Mountain Sandstone (TNS) aquifer occurs at relatively shallow depths. The investigation is aimed at assessing the geological, hydrogeological and hydrochemical characteristics of the HIS and any other aquifers present, with the object of providing quantitative data for use in future decisions on the water resource management of the area. In order to achieve these objectives, field work, involving a hydrocensus, geological mapping, geophysical exploration, drilling, aquifer testing and hydrochemical sampling was carried out. Analysis of these data provided information on the extent of the aquifers, their hydrogeological characteristics and the chemical nature of the various groundwater types.
- Full Text:
- Date Issued: 1985
A novel adjuvant : polymerised serum albumin beads
- Authors: Dewar, John Barr
- Date: 1985
- Subjects: Antigens , Serum albumin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4104 , http://hdl.handle.net/10962/d1011146 , Antigens , Serum albumin
- Description: Lee, T. et al (1981) proposed the encapsulation of hormones such as progesterone into serum albumin beads, such that their in vivo proteolysis would allow a gradual release of hormone at low levels, for extended hormone action. It was proposed, in the Department of Microbiology, Rhodes University, to replace the hormone component of the above bead formulation, with virus as antigen, in the development of a vaccine. Beads optimally crosslinked at 1% final glutaraldehyde concentration, containing Nodamura virus, were shown to promote an adjuvant effect in vivo, analogous to the release of antigen from Freund's Complete Adjuvant (FCA), so that extended immunostimulation resulted. It was shown that soluble antigen promoted a short-lived primary immune response, peaking around day 25 following inoculation. Antigen presented in beads, on the other hand, initially elicited a low humoral response, but this response gradually increased up to a peak around day 110 post inoculation, before decreasing. No apparent adverse side-effects were noted following inoculation of antigen-containing serum albumin beads, compared to necrosis following antigen in FCA inoculation, supporting the proposal of using albumin homotypic for the test inoculee animal, so that the beads would themselves be non-immunogenic and would merely act as a vehicle in the vaccine formulation. The indirect enzyme-linked immunosorbent assay (ELISA) was used to monitor the humoral response to antigen following inoculation. Results showed that covalent crosslinking of albumin in the formation of the beads did not promote immunogenicity on the part of the chemically altered albumin. The ELISA test was used to indicate the kinetics of the IgG response to Nodamura virus when presented in formulations such as: Freely soluble virus or its subunit; soluble intact virus inactivated by treatment with glutaraldehyde; intact virus entrapped in serum albumin beads cross; linked at different percentage final glutaraldehyde concentrations and also virus subunit prepared in albumin beads. The presence of virus-neutral ising antibodies was noted in serum obtained from rabbits inoculated with virus entrapped in albumin beads. Virus infectivity, titrated in mice, showed protection against virus challenge after incubation of virus with serum obtained above.
- Full Text:
- Date Issued: 1985
- Authors: Dewar, John Barr
- Date: 1985
- Subjects: Antigens , Serum albumin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4104 , http://hdl.handle.net/10962/d1011146 , Antigens , Serum albumin
- Description: Lee, T. et al (1981) proposed the encapsulation of hormones such as progesterone into serum albumin beads, such that their in vivo proteolysis would allow a gradual release of hormone at low levels, for extended hormone action. It was proposed, in the Department of Microbiology, Rhodes University, to replace the hormone component of the above bead formulation, with virus as antigen, in the development of a vaccine. Beads optimally crosslinked at 1% final glutaraldehyde concentration, containing Nodamura virus, were shown to promote an adjuvant effect in vivo, analogous to the release of antigen from Freund's Complete Adjuvant (FCA), so that extended immunostimulation resulted. It was shown that soluble antigen promoted a short-lived primary immune response, peaking around day 25 following inoculation. Antigen presented in beads, on the other hand, initially elicited a low humoral response, but this response gradually increased up to a peak around day 110 post inoculation, before decreasing. No apparent adverse side-effects were noted following inoculation of antigen-containing serum albumin beads, compared to necrosis following antigen in FCA inoculation, supporting the proposal of using albumin homotypic for the test inoculee animal, so that the beads would themselves be non-immunogenic and would merely act as a vehicle in the vaccine formulation. The indirect enzyme-linked immunosorbent assay (ELISA) was used to monitor the humoral response to antigen following inoculation. Results showed that covalent crosslinking of albumin in the formation of the beads did not promote immunogenicity on the part of the chemically altered albumin. The ELISA test was used to indicate the kinetics of the IgG response to Nodamura virus when presented in formulations such as: Freely soluble virus or its subunit; soluble intact virus inactivated by treatment with glutaraldehyde; intact virus entrapped in serum albumin beads cross; linked at different percentage final glutaraldehyde concentrations and also virus subunit prepared in albumin beads. The presence of virus-neutral ising antibodies was noted in serum obtained from rabbits inoculated with virus entrapped in albumin beads. Virus infectivity, titrated in mice, showed protection against virus challenge after incubation of virus with serum obtained above.
- Full Text:
- Date Issued: 1985
A study of germination and flowering in Cichorium intybus. L
- Authors: Minnaar, Hugo Roelof
- Date: 1985
- Subjects: Chicory -- South Africa Germination Seeds -- Development Plants -- Flowering of
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4178 , http://hdl.handle.net/10962/d1002027
- Description: Chicory (Cichorium intybus L) is a deep rooted biennial (or weakly perennial) composite that is grown as an annual in South Africa for its parsnip-like root. In its wild state the plant is a perennial with thin fibrous roots, but, through selection and propagation, cultivars with large, fleshy roots have been developed. From a purely horticultural standpoint, chicory is of interest as a pot-herb, a salad plant and as a root (Bailey, 1942) . As a root, the chicory plant represents an important article of commerce. In South Africa, the plants are grown virtually exclusively for their roots which, after drying, roasting and grinding, are used as an additive to, or substitute for, coffee (Introduction p. 11)
- Full Text:
- Date Issued: 1985
- Authors: Minnaar, Hugo Roelof
- Date: 1985
- Subjects: Chicory -- South Africa Germination Seeds -- Development Plants -- Flowering of
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4178 , http://hdl.handle.net/10962/d1002027
- Description: Chicory (Cichorium intybus L) is a deep rooted biennial (or weakly perennial) composite that is grown as an annual in South Africa for its parsnip-like root. In its wild state the plant is a perennial with thin fibrous roots, but, through selection and propagation, cultivars with large, fleshy roots have been developed. From a purely horticultural standpoint, chicory is of interest as a pot-herb, a salad plant and as a root (Bailey, 1942) . As a root, the chicory plant represents an important article of commerce. In South Africa, the plants are grown virtually exclusively for their roots which, after drying, roasting and grinding, are used as an additive to, or substitute for, coffee (Introduction p. 11)
- Full Text:
- Date Issued: 1985
A study of the molecular variation between orbivirus proteins
- Authors: Whistler, Toni
- Date: 1985 , 2013-03-13
- Subjects: Proteins -- Analysis , Polypeptides , Bluetongue virus , Orbivirus infections
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3892 , http://hdl.handle.net/10962/d1003290 , Proteins -- Analysis , Polypeptides , Bluetongue virus , Orbivirus infections
- Description: The aim of this study was to initiate a structural analysis of the capsid polypeptides from several serotypes of bluetongue virus in order to provide insight into the relatedness and possible origins of the different serotypes. Tryptic peptide mapping of ¹²⁵I-labelled group antigen by ion exchange chromatography was used to assess the structural relatedness of seven BTV serotypes from Southern Africa, North America and Australia. Each serotype had several tyrosine containing tryptic peptides which were unique, but approximately 35% of the peptides analyzed were found to be highly conserved between all 7 serotypes. BTV-20 appeared to be closely related to BTV-B and these two serotypes with BTV-4 and BTV-17 appeared to form a closely knit central cluster. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
- Authors: Whistler, Toni
- Date: 1985 , 2013-03-13
- Subjects: Proteins -- Analysis , Polypeptides , Bluetongue virus , Orbivirus infections
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3892 , http://hdl.handle.net/10962/d1003290 , Proteins -- Analysis , Polypeptides , Bluetongue virus , Orbivirus infections
- Description: The aim of this study was to initiate a structural analysis of the capsid polypeptides from several serotypes of bluetongue virus in order to provide insight into the relatedness and possible origins of the different serotypes. Tryptic peptide mapping of ¹²⁵I-labelled group antigen by ion exchange chromatography was used to assess the structural relatedness of seven BTV serotypes from Southern Africa, North America and Australia. Each serotype had several tyrosine containing tryptic peptides which were unique, but approximately 35% of the peptides analyzed were found to be highly conserved between all 7 serotypes. BTV-20 appeared to be closely related to BTV-B and these two serotypes with BTV-4 and BTV-17 appeared to form a closely knit central cluster. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
A study of the numinous presence in Tennyson's poetry
- Louw, Denise Elizabeth Laurence
- Authors: Louw, Denise Elizabeth Laurence
- Date: 1985
- Subjects: Tennyson, Alfred Tennyson, Baron, 1809-1892 -- Criticism and interpretation , English poetry -- 19th century -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2268 , http://hdl.handle.net/10962/d1005891 , Tennyson, Alfred Tennyson, Baron, 1809-1892 -- Criticism and interpretation , English poetry -- 19th century -- History and criticism
- Description: From Preface: A reader looking to this study for a charting of the diverse religious views held by Tennyson at different periods in his life may be disappointed. My primary concern has been not with religious forms, but with the numinous impulse. However, though I approached the topic with a completely open mind, I find my own Christian convictions have been strengthened through the study of Tennyson's poetry. As the title indicates, I have not attempted to deal with the plays. To explore both the poetry and the plays in a study of this length would have been impossible. I have perhaps been somewhat unorthodox in attempting to combine several disciplines, especially since I cannot claim to be a specialist in the areas concerned. However, I felt it necessary to approach the subject from a number of points of view, and to see to what extent the results could be said to converge on some sort of central "truth". When I have despaired of being able to do justice to a particular aspect within the imposed limits, I have sometimes found comfort in the words of Alan Sinfield (The Language of Tennyson's "In Memoriam", p.211): "We can only endeavour continually to approach a little closer to the central mystery; the ma j or advances will be infrequent, but most attempts should furnish one or two hints which others will develop. "
- Full Text:
- Date Issued: 1985
- Authors: Louw, Denise Elizabeth Laurence
- Date: 1985
- Subjects: Tennyson, Alfred Tennyson, Baron, 1809-1892 -- Criticism and interpretation , English poetry -- 19th century -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2268 , http://hdl.handle.net/10962/d1005891 , Tennyson, Alfred Tennyson, Baron, 1809-1892 -- Criticism and interpretation , English poetry -- 19th century -- History and criticism
- Description: From Preface: A reader looking to this study for a charting of the diverse religious views held by Tennyson at different periods in his life may be disappointed. My primary concern has been not with religious forms, but with the numinous impulse. However, though I approached the topic with a completely open mind, I find my own Christian convictions have been strengthened through the study of Tennyson's poetry. As the title indicates, I have not attempted to deal with the plays. To explore both the poetry and the plays in a study of this length would have been impossible. I have perhaps been somewhat unorthodox in attempting to combine several disciplines, especially since I cannot claim to be a specialist in the areas concerned. However, I felt it necessary to approach the subject from a number of points of view, and to see to what extent the results could be said to converge on some sort of central "truth". When I have despaired of being able to do justice to a particular aspect within the imposed limits, I have sometimes found comfort in the words of Alan Sinfield (The Language of Tennyson's "In Memoriam", p.211): "We can only endeavour continually to approach a little closer to the central mystery; the ma j or advances will be infrequent, but most attempts should furnish one or two hints which others will develop. "
- Full Text:
- Date Issued: 1985
Changes in the image of the feminine from Giotto to Raphael
- Authors: Crossley, Elizabeth Ellen
- Date: 1985
- Subjects: Giotto, 1266?-1337 Feminine beauty (Aesthetics) Women in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2471 , http://hdl.handle.net/10962/d1009448
- Description: From Introduction: The ideal of femininity which developed in Renaissance painting, was a visual and psychological type which was to become the Western European Christian formula of the feminine. This type has survived until the present day, so a discussion of its origins can be revealing for us in the twentieth century, especially as it has been neglected in traditional art historical works. In this essay, the changes in the image of the feminine, in just under three hundred years of Florentine painting, starting with Giotto1. and ending with Raphael~· will be covered. The images will be taken from the wo rk of artists who were Florentine in training, who worked in the city or who were strongly influenced by the Florentine style of painting. I have divided the paintings I have studied into three sections. In the Religious section the paintings are mainly of Mary. The Mythological images refer to Greek and Roman myths and the humanistic interpretations of them. Finally, the Portrait and Genre images are selected on the following basis: In the genre paintings they are sometimes part of works related to religion or mythology, but, in their handling, the painters treat the figures as real human beings rather than holy or mythological figures. In others they are bona fide portrait representations. 3. I have made the above distinction because I expect that the gap between religio-mythological images and portraits will give some indication of the difference between the ideal and the reality for women of that time. The images will be analysed and changes noted in favoured types, gestures, expressions, movements, placing in the composition, relationships to others, favoured themes, costume, colour and symbols. I will point out as I proceed the effects that these elements had on the mood and tone of each image.
- Full Text:
- Date Issued: 1985
- Authors: Crossley, Elizabeth Ellen
- Date: 1985
- Subjects: Giotto, 1266?-1337 Feminine beauty (Aesthetics) Women in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2471 , http://hdl.handle.net/10962/d1009448
- Description: From Introduction: The ideal of femininity which developed in Renaissance painting, was a visual and psychological type which was to become the Western European Christian formula of the feminine. This type has survived until the present day, so a discussion of its origins can be revealing for us in the twentieth century, especially as it has been neglected in traditional art historical works. In this essay, the changes in the image of the feminine, in just under three hundred years of Florentine painting, starting with Giotto1. and ending with Raphael~· will be covered. The images will be taken from the wo rk of artists who were Florentine in training, who worked in the city or who were strongly influenced by the Florentine style of painting. I have divided the paintings I have studied into three sections. In the Religious section the paintings are mainly of Mary. The Mythological images refer to Greek and Roman myths and the humanistic interpretations of them. Finally, the Portrait and Genre images are selected on the following basis: In the genre paintings they are sometimes part of works related to religion or mythology, but, in their handling, the painters treat the figures as real human beings rather than holy or mythological figures. In others they are bona fide portrait representations. 3. I have made the above distinction because I expect that the gap between religio-mythological images and portraits will give some indication of the difference between the ideal and the reality for women of that time. The images will be analysed and changes noted in favoured types, gestures, expressions, movements, placing in the composition, relationships to others, favoured themes, costume, colour and symbols. I will point out as I proceed the effects that these elements had on the mood and tone of each image.
- Full Text:
- Date Issued: 1985
Comparative bioavailability and ranking of topical corticosteroid formulations
- Authors: Meyer, Eric
- Date: 1985
- Subjects: Adrenocortical hormones -- Therapeutic use Drugs -- Bioavailability Drugs -- Dosage forms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3732 , http://hdl.handle.net/10962/d1001471
- Description: Numerous experiments in recent years have indicated differences in the bioavailability of corticosteroids from seemingly identical topical dosage forms. The human blanching assay was utilized in this study to assess the comparative blanching activities of various locally manufactured proprietary corticosteroid preparations. The first experiment was performed to assess the relative blanching activities of six semi - solid preparations containing the same concentration of betamethasone 17-valerate. The preparations used were Betnovate cream and ointment, Persivate cream and ointment and Celestoderm-V cream and ointment. This was followed, in the second experiment, by the investigation of the blanching activities of two lotions containing betamethasone 17-valerate (Betnovate and Celestoderm-V) and a lotion containing betamethasone 17,21- dipropionate (Diprosone). The third experiment involved a study of six semi-solid proprietary corticosteroid-containing formulations, viz. Dermovate (clobetasol propionate) cream and ointment, Betnovate (betamethasone 17-valerate) cream and ointment and Eumovate (clobetasone butyrate) cream and ointment. This investigation was prompted by claims in advertisements in the medical media that Dermovate is therapeutically more efficacious than Betnovate which is more efficacious than Eumovate. The penultimate experiment in this study served the purpose of finding a corticosteroid-containing preparation that falls into the moderately potent group of corticosteroid formulations, as described in the United Kingdom MIMS. This preparation was used in the final experiment which was undertaken to ascertain the potency category of Florone (diflorasone diacetate) cream and ointment.
- Full Text:
- Date Issued: 1985
- Authors: Meyer, Eric
- Date: 1985
- Subjects: Adrenocortical hormones -- Therapeutic use Drugs -- Bioavailability Drugs -- Dosage forms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3732 , http://hdl.handle.net/10962/d1001471
- Description: Numerous experiments in recent years have indicated differences in the bioavailability of corticosteroids from seemingly identical topical dosage forms. The human blanching assay was utilized in this study to assess the comparative blanching activities of various locally manufactured proprietary corticosteroid preparations. The first experiment was performed to assess the relative blanching activities of six semi - solid preparations containing the same concentration of betamethasone 17-valerate. The preparations used were Betnovate cream and ointment, Persivate cream and ointment and Celestoderm-V cream and ointment. This was followed, in the second experiment, by the investigation of the blanching activities of two lotions containing betamethasone 17-valerate (Betnovate and Celestoderm-V) and a lotion containing betamethasone 17,21- dipropionate (Diprosone). The third experiment involved a study of six semi-solid proprietary corticosteroid-containing formulations, viz. Dermovate (clobetasol propionate) cream and ointment, Betnovate (betamethasone 17-valerate) cream and ointment and Eumovate (clobetasone butyrate) cream and ointment. This investigation was prompted by claims in advertisements in the medical media that Dermovate is therapeutically more efficacious than Betnovate which is more efficacious than Eumovate. The penultimate experiment in this study served the purpose of finding a corticosteroid-containing preparation that falls into the moderately potent group of corticosteroid formulations, as described in the United Kingdom MIMS. This preparation was used in the final experiment which was undertaken to ascertain the potency category of Florone (diflorasone diacetate) cream and ointment.
- Full Text:
- Date Issued: 1985
Computer control of a barry research chirpsounder
- Authors: Evans, Geoffrey Philip
- Date: 1985
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5507 , http://hdl.handle.net/10962/d1007495
- Description: This thesis describes the design and development of a computer-based controller together with additional hardware that greatly extends the capabilities of a Barry Research VOS-1 Chirpsounder. The measurement of the virtual height of the ionosphere as a function of frequency using pulse- and frequency-modulated carrier wave (FMCW techniques is described and the concept of the so called "digital" ionosonde is introduced. The modifications required for the standard Chirpsounder to perform as a versatile digital chirp ionosonde are discussed. Simplified block diagrams are used to describe the Controller hardware which is fully described in two comprehensive service manuals which have been included as appendices. Important aspects of the Controller software and data storage formats are described in detail. The emphasis is then placed on system capabilities. An operators' software manual which describes system initialization and operation in terms of system commands is included as an appendix. Results of tests at both Grahamstown, South Africa , and at the SANAE base in the Antarctic are presented.
- Full Text:
- Date Issued: 1985
- Authors: Evans, Geoffrey Philip
- Date: 1985
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5507 , http://hdl.handle.net/10962/d1007495
- Description: This thesis describes the design and development of a computer-based controller together with additional hardware that greatly extends the capabilities of a Barry Research VOS-1 Chirpsounder. The measurement of the virtual height of the ionosphere as a function of frequency using pulse- and frequency-modulated carrier wave (FMCW techniques is described and the concept of the so called "digital" ionosonde is introduced. The modifications required for the standard Chirpsounder to perform as a versatile digital chirp ionosonde are discussed. Simplified block diagrams are used to describe the Controller hardware which is fully described in two comprehensive service manuals which have been included as appendices. Important aspects of the Controller software and data storage formats are described in detail. The emphasis is then placed on system capabilities. An operators' software manual which describes system initialization and operation in terms of system commands is included as an appendix. Results of tests at both Grahamstown, South Africa , and at the SANAE base in the Antarctic are presented.
- Full Text:
- Date Issued: 1985
Concurrency in modula-2
- Authors: Sewry, David Andrew
- Date: 1985 , 2013-03-13
- Subjects: Modula-2 (Computer program language) , Programming languages (Electronic computers) , Computer multitasking
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4582 , http://hdl.handle.net/10962/d1004369 , Modula-2 (Computer program language) , Programming languages (Electronic computers) , Computer multitasking
- Description: A concurrent program is one in which a number of processes are considered to be active simultaneously . It is possib l e to t hink of a process as being a separate sequential program executing independently of other processes, although perhaps communicating with them at desired pOints . The concurrent program, as a whole, can be executed in one of two ways: il ii) in true concurrent manner, wi th each process executing on a dedicated processor in a quasi - concurrent manner, where a processor's processes . time is multiplexed between single the There are two motivations for the study of concurrency in programming languages : i) concurrent programming facilities can be exploited in systems where one has more t han one processor . As technology i mproves, machines having multiple processors will proliferate ii) concurrent p r ogramming facilities may allow programs to be structured as independent , bu t co - operating, processes which can then be implemented on a single processor system . This structure may be more natural to the programmer then the traditional sequential structures. An example is provided by Conway's - 1- Clearly, languages Pascal) problem [Ben82] . by their very nature, traditional sequential- type (Fortran, Basic, Cobol and earlier versions of prove inadequate for the purposes of concurrent programming without considerable extension (which some manufacturers have provided, rendering their compilers non standard-conforming). The general convenience of high level languages provides strong motivation for their development for rea l time programming. Modula - 2 [Wir83] is but one of a number of such r ecently developed languages, designed not only to fulfil a "sequential" role but also to offer facilities for concurrent programming. Developed by Niklaus Wirth in 1979 as a successor to Pascal and Modula, it is intended to serve under the banner of a generalpurpose systems - implementation language. This thesis investigates concurrency i n Modula - 2 and takes the following form: i ) an analYSis of the concurrent facilities offered ii) problems and difficulties associated with these facilities iii) improveme nts and enhancements, including the feasibility of using Modula - 2 to simulate constructs found in other languages, such as the Hoare monitor [Hoa74] and the Ada rendezvous [Uni81]. - 2- Each section concludes with an appraisal of the work conducted in that section . The final section consists of a critical assessment of those Modula - 2 language constructs and facilities provided for the implementation of concurrency and a brief look at concurrency in Modula, Modula-2's predecessor. - Introduction. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
- Authors: Sewry, David Andrew
- Date: 1985 , 2013-03-13
- Subjects: Modula-2 (Computer program language) , Programming languages (Electronic computers) , Computer multitasking
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4582 , http://hdl.handle.net/10962/d1004369 , Modula-2 (Computer program language) , Programming languages (Electronic computers) , Computer multitasking
- Description: A concurrent program is one in which a number of processes are considered to be active simultaneously . It is possib l e to t hink of a process as being a separate sequential program executing independently of other processes, although perhaps communicating with them at desired pOints . The concurrent program, as a whole, can be executed in one of two ways: il ii) in true concurrent manner, wi th each process executing on a dedicated processor in a quasi - concurrent manner, where a processor's processes . time is multiplexed between single the There are two motivations for the study of concurrency in programming languages : i) concurrent programming facilities can be exploited in systems where one has more t han one processor . As technology i mproves, machines having multiple processors will proliferate ii) concurrent p r ogramming facilities may allow programs to be structured as independent , bu t co - operating, processes which can then be implemented on a single processor system . This structure may be more natural to the programmer then the traditional sequential structures. An example is provided by Conway's - 1- Clearly, languages Pascal) problem [Ben82] . by their very nature, traditional sequential- type (Fortran, Basic, Cobol and earlier versions of prove inadequate for the purposes of concurrent programming without considerable extension (which some manufacturers have provided, rendering their compilers non standard-conforming). The general convenience of high level languages provides strong motivation for their development for rea l time programming. Modula - 2 [Wir83] is but one of a number of such r ecently developed languages, designed not only to fulfil a "sequential" role but also to offer facilities for concurrent programming. Developed by Niklaus Wirth in 1979 as a successor to Pascal and Modula, it is intended to serve under the banner of a generalpurpose systems - implementation language. This thesis investigates concurrency i n Modula - 2 and takes the following form: i ) an analYSis of the concurrent facilities offered ii) problems and difficulties associated with these facilities iii) improveme nts and enhancements, including the feasibility of using Modula - 2 to simulate constructs found in other languages, such as the Hoare monitor [Hoa74] and the Ada rendezvous [Uni81]. - 2- Each section concludes with an appraisal of the work conducted in that section . The final section consists of a critical assessment of those Modula - 2 language constructs and facilities provided for the implementation of concurrency and a brief look at concurrency in Modula, Modula-2's predecessor. - Introduction. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
East London: the creation and development of a frontier community, 1835-1873
- Tankard, Keith Peter Tempest
- Authors: Tankard, Keith Peter Tempest
- Date: 1985
- Subjects: East London (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2580 , http://hdl.handle.net/10962/d1004550 , East London (South Africa) -- History
- Description: From Preface: Although East London exists today as one of the major ports of South Africa, the city appears to have been forgotten by historians. Little has been done to chronicle its history. In 1932, Bruce Gordon set out to initiate this research and he investigated East London's history to the end of 1865. However, Gordon's thesis, though accurate, is short and inadequate by today's standards. Furthermore, no-one continued from where Gordon left off. Several articles have been written over the previous six decades, each dealing with aspects of East London's past but these, on the whole, are inaccurate and misleading. The time is ripe, therefore, to begin again the research into the history of East London. East London owed its foundation to the state of unrest which existed on the eastern frontier of the Cape of Good Hope between 1834 and 1847. Although the geographic and climatic conditions were in the port's favour, East London remained in a suppressed condition until about 1870. It is the purpose of this thesis to examine the factors which gave rise to this truncated growth. The thesis will examine first the wider perspective of imperial and colonial policy in which East London was conceived and in which it had its early existence. The implications of this policy for East London at the various levels of the port's development will be explored in subsequent chapters. British and Cape colonial policy, however, evolved in a chronological sequence and so the examination of this policy likewise will tend to follow a chronological pattern within each chapter. The establishment of Port Rex in November/December 1836 enters into East London's story in several ways: its political development, the creation and development of the harbour on the Buffalo River, the evolution of trade, the growth of the community and the status of the black population at the mouth of the Buffalo River. It has been found necessary, therefore, to refer often to this beginning of East London's history. Although several theses have already been written which deal with topics related to British Kaffraria, none of these do more than allude to the creation and development of East London. Although, for example, the German Settlers played an important role in the growth of the port, Schnell's thesis hardly mentions the two communities at Panmure and Cambridge. The research for this thesis led me to two important and little known sources of early information, both in Cape Town. The first was the multiple volumed "Unsorted Archives" on East London which consists of reports and letters to the Resident Magistrate. It is a treasure chest of information on East London's early years. The second source was G.M. Theal's newspapers, The Kaffrarian Recorder and East London Shipping Gazette and, later, The Kaffrarian, East London's second newspaper which was believed to have been lost until copies were discovered recently in the South African Library in Cape Town. Theal, later prominent as a historian, had a clear insight into the problems which confronted the community at East London and the editorials of his newspaper make interesting reading. East London's first newspaper is, unfortunately, still lost. It was the East London Times which had its first issue in January 1863, and lasted a mere two months. It consisted of half a sheet of foolscap printed on one side, the other side being left blank, the editor of the King William's Town Gazette wrote, "'for want of room' or from lack of matter."
- Full Text:
- Date Issued: 1985
- Authors: Tankard, Keith Peter Tempest
- Date: 1985
- Subjects: East London (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2580 , http://hdl.handle.net/10962/d1004550 , East London (South Africa) -- History
- Description: From Preface: Although East London exists today as one of the major ports of South Africa, the city appears to have been forgotten by historians. Little has been done to chronicle its history. In 1932, Bruce Gordon set out to initiate this research and he investigated East London's history to the end of 1865. However, Gordon's thesis, though accurate, is short and inadequate by today's standards. Furthermore, no-one continued from where Gordon left off. Several articles have been written over the previous six decades, each dealing with aspects of East London's past but these, on the whole, are inaccurate and misleading. The time is ripe, therefore, to begin again the research into the history of East London. East London owed its foundation to the state of unrest which existed on the eastern frontier of the Cape of Good Hope between 1834 and 1847. Although the geographic and climatic conditions were in the port's favour, East London remained in a suppressed condition until about 1870. It is the purpose of this thesis to examine the factors which gave rise to this truncated growth. The thesis will examine first the wider perspective of imperial and colonial policy in which East London was conceived and in which it had its early existence. The implications of this policy for East London at the various levels of the port's development will be explored in subsequent chapters. British and Cape colonial policy, however, evolved in a chronological sequence and so the examination of this policy likewise will tend to follow a chronological pattern within each chapter. The establishment of Port Rex in November/December 1836 enters into East London's story in several ways: its political development, the creation and development of the harbour on the Buffalo River, the evolution of trade, the growth of the community and the status of the black population at the mouth of the Buffalo River. It has been found necessary, therefore, to refer often to this beginning of East London's history. Although several theses have already been written which deal with topics related to British Kaffraria, none of these do more than allude to the creation and development of East London. Although, for example, the German Settlers played an important role in the growth of the port, Schnell's thesis hardly mentions the two communities at Panmure and Cambridge. The research for this thesis led me to two important and little known sources of early information, both in Cape Town. The first was the multiple volumed "Unsorted Archives" on East London which consists of reports and letters to the Resident Magistrate. It is a treasure chest of information on East London's early years. The second source was G.M. Theal's newspapers, The Kaffrarian Recorder and East London Shipping Gazette and, later, The Kaffrarian, East London's second newspaper which was believed to have been lost until copies were discovered recently in the South African Library in Cape Town. Theal, later prominent as a historian, had a clear insight into the problems which confronted the community at East London and the editorials of his newspaper make interesting reading. East London's first newspaper is, unfortunately, still lost. It was the East London Times which had its first issue in January 1863, and lasted a mere two months. It consisted of half a sheet of foolscap printed on one side, the other side being left blank, the editor of the King William's Town Gazette wrote, "'for want of room' or from lack of matter."
- Full Text:
- Date Issued: 1985
Gerard Manley Hopkins's poetic art as "current language heightened" : (with reference to selected sonnets and in the light of contemporary stylistic theory)
- Authors: McDermott, Lydia Eva
- Date: 1985
- Subjects: Hopkins, Gerard Manley, 1844-1889 , English poetry -- 19th century -- History and criticism
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2337 , http://hdl.handle.net/10962/d1002019
- Description: The aim of this thesis is twofold: To examine Hopkins's writings on poetics and to relate these to modern theories of poetic stylistics; and to show, through an examination of two sets of Hopkins sonnets, the ways in which Hopkins's writings on language and poetics are reflected in his verse (Introductory outline, p. 5)
- Full Text:
- Date Issued: 1985
- Authors: McDermott, Lydia Eva
- Date: 1985
- Subjects: Hopkins, Gerard Manley, 1844-1889 , English poetry -- 19th century -- History and criticism
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2337 , http://hdl.handle.net/10962/d1002019
- Description: The aim of this thesis is twofold: To examine Hopkins's writings on poetics and to relate these to modern theories of poetic stylistics; and to show, through an examination of two sets of Hopkins sonnets, the ways in which Hopkins's writings on language and poetics are reflected in his verse (Introductory outline, p. 5)
- Full Text:
- Date Issued: 1985
Granitoid related Sn-W mineralisation with special reference to southern Africa, the Variscan Belt in Europe, and the Malay Peninsula
- Authors: Bentley, Philip Nelson
- Date: 1985
- Subjects: Geotectonic settings , Granitoids , Granites , Tin-tungsten , Mineralisation , Greisen environment , Minerals , Exploration
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4908 , http://hdl.handle.net/10962/d1001568
- Description: A review of the geotectonic settings of granitoids and various tin-tungsten provinces in Europe, Malaysia and southern Africa shows a close spatial and temporal association of mineralisation to S-type ilmenite series granitoids. Granitoids with these affinities are derived from crustal anatexis and are most commonly found in continental collision and different ensialic, intraplate orogenic settings, (e.g. SW England, Malaysia, Namibia) as well as in association with anorogenic magmatism (Nigeria, Brazil, South Africa). Tin-tungsten mineralisation is related to late- to post-tectonic granites, emplaced into areas of substantial tectonic thickening. Crustal anatexis leads to an observable calcalkaline chemical trend, with a source of gabbroic or amphibolite composition through anatexis to; mafic-intermediate enclaves, para-autochthonous anatectic granitoids (tonalite, granodiorite), to intermediate level quartz monzonite, granodiorite, biotite-granite, to late-tectonic highly fractionated muscovite-bearing granites, and high level porphyry intrusions. Mineralisation is spatially related to apical protrusions of the youngest most differentiated granite. Various mineralised environments are recognised, including endogranitic veins, primary disseminations, pegmatites and pipes, and exogranitic stockwork and fissure veins, and replacement bodies. A common factor to all these deposits is the inherent greisen environment, characterised by postmagmatic metasomatic alteration and mineral deposition. Common alteration mineral assemblages include albite, quartz, muscovite, tourmaline, and fluorite ∓ topaz. Ore mineral assemblages commonly display a paragenetic sequence of oxides (cassiterite, wolframite, scheelite), followed by sulphides (molybdenite, pyrite, pyrrhotite, chalcopyrite sphalerite, arsenopyrite/loëllingite, Pb-Bi(Ag) sulphosalts) and then lower temperature carbonates (calcite, siderite, ankerite). Analysis of Pan African orogenic provinces in southern Africa (Damara and Saldanian Provinces) shows there is good potential for applying integrated exploration techniques in search of endo-exogreisen Sn-W systems. Careful analysis and interpretation of granitoid geochemistry (K₂0, Na₂0, FeO/Fe₂0₃, F, B, Sn, W, Mo, Cu, Rb, Sr, Ti, Zr) should aid delineation of Sn-W and Mo-Cu metallogenic provinces in these regions. Magnetic susceptibility determinations should also aid distinction of S-type ilmenite series (less than 1 x lO⁻⁴emu/g ) from I-type magnetite series (more than 1 x lO⁻⁴emu/g ) granitoids
- Full Text:
- Date Issued: 1985
- Authors: Bentley, Philip Nelson
- Date: 1985
- Subjects: Geotectonic settings , Granitoids , Granites , Tin-tungsten , Mineralisation , Greisen environment , Minerals , Exploration
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4908 , http://hdl.handle.net/10962/d1001568
- Description: A review of the geotectonic settings of granitoids and various tin-tungsten provinces in Europe, Malaysia and southern Africa shows a close spatial and temporal association of mineralisation to S-type ilmenite series granitoids. Granitoids with these affinities are derived from crustal anatexis and are most commonly found in continental collision and different ensialic, intraplate orogenic settings, (e.g. SW England, Malaysia, Namibia) as well as in association with anorogenic magmatism (Nigeria, Brazil, South Africa). Tin-tungsten mineralisation is related to late- to post-tectonic granites, emplaced into areas of substantial tectonic thickening. Crustal anatexis leads to an observable calcalkaline chemical trend, with a source of gabbroic or amphibolite composition through anatexis to; mafic-intermediate enclaves, para-autochthonous anatectic granitoids (tonalite, granodiorite), to intermediate level quartz monzonite, granodiorite, biotite-granite, to late-tectonic highly fractionated muscovite-bearing granites, and high level porphyry intrusions. Mineralisation is spatially related to apical protrusions of the youngest most differentiated granite. Various mineralised environments are recognised, including endogranitic veins, primary disseminations, pegmatites and pipes, and exogranitic stockwork and fissure veins, and replacement bodies. A common factor to all these deposits is the inherent greisen environment, characterised by postmagmatic metasomatic alteration and mineral deposition. Common alteration mineral assemblages include albite, quartz, muscovite, tourmaline, and fluorite ∓ topaz. Ore mineral assemblages commonly display a paragenetic sequence of oxides (cassiterite, wolframite, scheelite), followed by sulphides (molybdenite, pyrite, pyrrhotite, chalcopyrite sphalerite, arsenopyrite/loëllingite, Pb-Bi(Ag) sulphosalts) and then lower temperature carbonates (calcite, siderite, ankerite). Analysis of Pan African orogenic provinces in southern Africa (Damara and Saldanian Provinces) shows there is good potential for applying integrated exploration techniques in search of endo-exogreisen Sn-W systems. Careful analysis and interpretation of granitoid geochemistry (K₂0, Na₂0, FeO/Fe₂0₃, F, B, Sn, W, Mo, Cu, Rb, Sr, Ti, Zr) should aid delineation of Sn-W and Mo-Cu metallogenic provinces in these regions. Magnetic susceptibility determinations should also aid distinction of S-type ilmenite series (less than 1 x lO⁻⁴emu/g ) from I-type magnetite series (more than 1 x lO⁻⁴emu/g ) granitoids
- Full Text:
- Date Issued: 1985
High performance liquid chromatographic analysis of erythromycin in serum and urine
- Authors: Stubbs, Christopher
- Date: 1985 , 2013-03-13
- Subjects: High performance liquid chromatography , Erythromycin , Erythromycin -- Pharmacokinetics , Chromatographic analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3813 , http://hdl.handle.net/10962/d1004581 , High performance liquid chromatography , Erythromycin , Erythromycin -- Pharmacokinetics , Chromatographic analysis
- Description: Erythromycin, a macrolide antibiotic used mainly against gram-positive bacteria has been in clinical use since 1952 (1). Previous pharmacokinetic data published on this antibiotic have been derived predominantly from microbiological assay techniques. However, these techniques are relatively imprecise as well as being non-specific and extremely tedious to perform. A novel high performance liquid chromatographic analysis of erythromycin in human serum and urine using U.V. detection at 200 nm and/or electrochemical detection using both an amperometric and a coulometric electrochemical detector is presented. The method involves a solid phase extraction procedure followed by a simple phase separation step and chromatography on a reverse phase column. In order to select the optimum U.V. detector for this analysis, five "state of the art" detectors were compared in terms of their signal-to-noise ratios at U.V. wavelengths between 200 and 210 nm. A known metabolite des-N-methylerythromycin is readily detectable using U.V. detection, whilst another metabolite/degradation product anhydroerythromycin is not seen using U.V. detection but is readily observable using an electrochemical detector. The method has a limit of sensitivity of 0.25 μg/mL and 1.00 μg/mL in serum and urine respectively (U.V. detection) and is sufficiently sensitive to monitor serum and urine concentrations of erythromycin in man after administration of a single 500 mg erythromycin stearate tablet. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
- Authors: Stubbs, Christopher
- Date: 1985 , 2013-03-13
- Subjects: High performance liquid chromatography , Erythromycin , Erythromycin -- Pharmacokinetics , Chromatographic analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3813 , http://hdl.handle.net/10962/d1004581 , High performance liquid chromatography , Erythromycin , Erythromycin -- Pharmacokinetics , Chromatographic analysis
- Description: Erythromycin, a macrolide antibiotic used mainly against gram-positive bacteria has been in clinical use since 1952 (1). Previous pharmacokinetic data published on this antibiotic have been derived predominantly from microbiological assay techniques. However, these techniques are relatively imprecise as well as being non-specific and extremely tedious to perform. A novel high performance liquid chromatographic analysis of erythromycin in human serum and urine using U.V. detection at 200 nm and/or electrochemical detection using both an amperometric and a coulometric electrochemical detector is presented. The method involves a solid phase extraction procedure followed by a simple phase separation step and chromatography on a reverse phase column. In order to select the optimum U.V. detector for this analysis, five "state of the art" detectors were compared in terms of their signal-to-noise ratios at U.V. wavelengths between 200 and 210 nm. A known metabolite des-N-methylerythromycin is readily detectable using U.V. detection, whilst another metabolite/degradation product anhydroerythromycin is not seen using U.V. detection but is readily observable using an electrochemical detector. The method has a limit of sensitivity of 0.25 μg/mL and 1.00 μg/mL in serum and urine respectively (U.V. detection) and is sufficiently sensitive to monitor serum and urine concentrations of erythromycin in man after administration of a single 500 mg erythromycin stearate tablet. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
Influence of endogenous female sex-steroids on mutagen metabolism
- Authors: Goold, Richard David
- Date: 1985 , 2013-03-15
- Subjects: Mutagenesis , Drugs -- Metabolism , Steroid hormones -- Receptors , Cytochrome P-450
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3819 , http://hdl.handle.net/10962/d1004919 , Mutagenesis , Drugs -- Metabolism , Steroid hormones -- Receptors , Cytochrome P-450
- Description: Cytochrome P-450, the terminal oxidase of the metabolic mono-oxygenase system, is thought to exist in multiple forms, which have differing substrate specificities, and are variably inducible by different enzyme inducers. Many mutagens, themselves unreactive, require metabolic activation by one or more of these cytochrome P-450-dependent microsomal enzymes for mutagenic activity. Such mutagens may be detected in the Salmonella mutagenicity test only by the incorporation of an hepatic microsomal (59) fraction into the assay (as a first approximation to in vivo metabolism). Induction of the microsomal enzymes by different agents enhances the metabolic activation of mutagens; in fact, many mutagens are only detected when the 59 fraction has been induced by appropriate agents. Inducers of the phenobarbital-type are known to enhance microsomal steroid hydroxylation when administered at supraphysiological levels, inducers of several mono-oxygenase activities. In turn, the steroids, have been reported to be The inductive effects of the female sex-steroids and the combined effects of steroid and phenobarbital (PB) pretreatment on the metabolic activation of four mutagens have been investigated using the Salmonella assay. Female Sprague-Dawley rats were pret reated with 17a-oestradiol (E2) or progesterone (PRG) , at a level of either 1 mg/kg or 20 mg / kg daily for 14 days. A duplicate set of similarly pretreated groups were also induced with PB. Hepatic microsomal fractions were prepared from each group and incubated with each of the te st mutagens in the presence of a tester strain known to detect each particular type of mutagen. Induction of the hepatic metabolizing system by PB increased the activation of the mutagens significantly (as reflected by an increased number of revertant prototrophic S .typhimurium colonies). The administration of PRG also caused significant, and dose-dependent, induction of the activation of af l atoxin B1, benzo(a)pyrene, and dimethylnitrosamine. In general, E2 exhibited no inductive effect, but it did produce an increase in the activation of aflatoxin B1 (a reaction which is known to be catalysed by a mono-oxygenase prefe rentially inducible by PB). When use was made of a microsomal fraction that was prepared from animals which were both steroidpretreated and induced by PB, mutagenic activation was of the same order of magnitude as that observed when induction was brought about by PB alone. The absence of additive effect, taken together with the observations already mentioned, indicate that steroids induce the same cytochrome isozymes that are induced by PB. The implications of sex-hormonal regulation of the metabolic activation of mutagens are briefly discussed. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
- Authors: Goold, Richard David
- Date: 1985 , 2013-03-15
- Subjects: Mutagenesis , Drugs -- Metabolism , Steroid hormones -- Receptors , Cytochrome P-450
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3819 , http://hdl.handle.net/10962/d1004919 , Mutagenesis , Drugs -- Metabolism , Steroid hormones -- Receptors , Cytochrome P-450
- Description: Cytochrome P-450, the terminal oxidase of the metabolic mono-oxygenase system, is thought to exist in multiple forms, which have differing substrate specificities, and are variably inducible by different enzyme inducers. Many mutagens, themselves unreactive, require metabolic activation by one or more of these cytochrome P-450-dependent microsomal enzymes for mutagenic activity. Such mutagens may be detected in the Salmonella mutagenicity test only by the incorporation of an hepatic microsomal (59) fraction into the assay (as a first approximation to in vivo metabolism). Induction of the microsomal enzymes by different agents enhances the metabolic activation of mutagens; in fact, many mutagens are only detected when the 59 fraction has been induced by appropriate agents. Inducers of the phenobarbital-type are known to enhance microsomal steroid hydroxylation when administered at supraphysiological levels, inducers of several mono-oxygenase activities. In turn, the steroids, have been reported to be The inductive effects of the female sex-steroids and the combined effects of steroid and phenobarbital (PB) pretreatment on the metabolic activation of four mutagens have been investigated using the Salmonella assay. Female Sprague-Dawley rats were pret reated with 17a-oestradiol (E2) or progesterone (PRG) , at a level of either 1 mg/kg or 20 mg / kg daily for 14 days. A duplicate set of similarly pretreated groups were also induced with PB. Hepatic microsomal fractions were prepared from each group and incubated with each of the te st mutagens in the presence of a tester strain known to detect each particular type of mutagen. Induction of the hepatic metabolizing system by PB increased the activation of the mutagens significantly (as reflected by an increased number of revertant prototrophic S .typhimurium colonies). The administration of PRG also caused significant, and dose-dependent, induction of the activation of af l atoxin B1, benzo(a)pyrene, and dimethylnitrosamine. In general, E2 exhibited no inductive effect, but it did produce an increase in the activation of aflatoxin B1 (a reaction which is known to be catalysed by a mono-oxygenase prefe rentially inducible by PB). When use was made of a microsomal fraction that was prepared from animals which were both steroidpretreated and induced by PB, mutagenic activation was of the same order of magnitude as that observed when induction was brought about by PB alone. The absence of additive effect, taken together with the observations already mentioned, indicate that steroids induce the same cytochrome isozymes that are induced by PB. The implications of sex-hormonal regulation of the metabolic activation of mutagens are briefly discussed. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
Mineralogy and petrology of the Townlands iron-rich ultramafic pegmatite
- Authors: Phillips, David
- Date: 1985 , 2013-09-09
- Subjects: Ultrabasic rocks -- South African -- Rustenburg , Platinum ores -- South Africa -- Rustenburg , Pegmatites -- South Africa -- Rustenburg , Mines and mineral resources -- South Africa -- Rustenburg
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5040 , http://hdl.handle.net/10962/d1007617 , Ultrabasic rocks -- South African -- Rustenburg , Platinum ores -- South Africa -- Rustenburg , Pegmatites -- South Africa -- Rustenburg , Mines and mineral resources -- South Africa -- Rustenburg
- Description: The Townlands iron-rich ultramafic pegmatite is a relatively large pipelike body situated in the western corner of Rustenburg Section, Rustenburg Platinum Mines. It is characterised by a strong negative magnetic signature and transgresses the noritic layered sequence of the upper critical zone of the Bushveld Complex. The layered rocks are downwarped in the vicinity of the pipe and are in sharp contact with the pegmatitic material. The pegmatite varies in composition between dunite and wehrlite, with the marginal zones being more wehrlitic in composition. Olivine (Fo₃₀ - Fo₅₂) and clinopyroxene (Wo₄₅En₃₀Fs₂₅ - Wo₄₅En₃₇Fs₁₈) are the dominant constituents and accessory phases include ilmenite, Ti -magnetite, apatite, amphiboles, chlorite-group minerals, biotite, ilvaite and a host of unusual ore minerals. The Fe-Ti oxides exhibit exsolution textures typically found in slowly cooled igneous rocks and temperatures of formati on are consi dered to be in excess of 800°C. The UG2 chromitite leader layers intersected by borehole TLP.l are enriched in Fe and Ti and exhibit compositions intermediate between chromite and Ti-magnetite. The ore mineral assemblage includes a primary sulphide assemblage consisting of troilite, chalcopyrite, cubanite and pentlandite, and an array of unusual phases formed by late-stage secondary processes. The unusual sulphides mooihoekite and haycockite, that occur in certain parts of the pegmatite, are considered to have formed by partial replacement of the primary assemblage and a possible paragenetic sequence is discussed. Mineral compositions and whole rock geochemical data are consistent with an origin for the pegmatite by crystallization from a fractionated melt. It is suggested that intercumulus fluids, trapped during the crystallization of the noritic layered sequence, accumulated in an area of structural weakness, in response to an increasing overburden pressure and/or tectonic activity. Evidence is also presented that indicates that the Townlands pegmatite may consist of at least two separate, but adjoining pegmatite bodies. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
- Authors: Phillips, David
- Date: 1985 , 2013-09-09
- Subjects: Ultrabasic rocks -- South African -- Rustenburg , Platinum ores -- South Africa -- Rustenburg , Pegmatites -- South Africa -- Rustenburg , Mines and mineral resources -- South Africa -- Rustenburg
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5040 , http://hdl.handle.net/10962/d1007617 , Ultrabasic rocks -- South African -- Rustenburg , Platinum ores -- South Africa -- Rustenburg , Pegmatites -- South Africa -- Rustenburg , Mines and mineral resources -- South Africa -- Rustenburg
- Description: The Townlands iron-rich ultramafic pegmatite is a relatively large pipelike body situated in the western corner of Rustenburg Section, Rustenburg Platinum Mines. It is characterised by a strong negative magnetic signature and transgresses the noritic layered sequence of the upper critical zone of the Bushveld Complex. The layered rocks are downwarped in the vicinity of the pipe and are in sharp contact with the pegmatitic material. The pegmatite varies in composition between dunite and wehrlite, with the marginal zones being more wehrlitic in composition. Olivine (Fo₃₀ - Fo₅₂) and clinopyroxene (Wo₄₅En₃₀Fs₂₅ - Wo₄₅En₃₇Fs₁₈) are the dominant constituents and accessory phases include ilmenite, Ti -magnetite, apatite, amphiboles, chlorite-group minerals, biotite, ilvaite and a host of unusual ore minerals. The Fe-Ti oxides exhibit exsolution textures typically found in slowly cooled igneous rocks and temperatures of formati on are consi dered to be in excess of 800°C. The UG2 chromitite leader layers intersected by borehole TLP.l are enriched in Fe and Ti and exhibit compositions intermediate between chromite and Ti-magnetite. The ore mineral assemblage includes a primary sulphide assemblage consisting of troilite, chalcopyrite, cubanite and pentlandite, and an array of unusual phases formed by late-stage secondary processes. The unusual sulphides mooihoekite and haycockite, that occur in certain parts of the pegmatite, are considered to have formed by partial replacement of the primary assemblage and a possible paragenetic sequence is discussed. Mineral compositions and whole rock geochemical data are consistent with an origin for the pegmatite by crystallization from a fractionated melt. It is suggested that intercumulus fluids, trapped during the crystallization of the noritic layered sequence, accumulated in an area of structural weakness, in response to an increasing overburden pressure and/or tectonic activity. Evidence is also presented that indicates that the Townlands pegmatite may consist of at least two separate, but adjoining pegmatite bodies. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1985
Philip Gibbs: war correspondent of a new dispensation
- Authors: Woodward, Christina Anna
- Date: 1985
- Subjects: Gibbs, Philip, 1877-1962 , War correspondents , War -- Press coverage , Mass media and war , Journalists
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2577 , http://hdl.handle.net/10962/d1003126 , Gibbs, Philip, 1877-1962 , War correspondents , War -- Press coverage , Mass media and war , Journalists
- Description: The process of democratization which appeared in the nineteenth century was partly responsible for the emergence of a mass readership. It consisted of the new urban population which had its own tastes and interests, intellectual capacity and purchasing power. The popular press was firmly established by 1900 and it radically altered the scope and style of daily journalism in its attempt to speak in the language of the majority. Philip Gibbs was one of the prominent journalists between 1900 and 1914. His aspiration to become a war correspondent stemmed from the image of the war correspondent as a figure of romance and adventure, the consequence of the militarist spirit of the age and the licence which granted him freedom of movement. Inevitably, the war correspondent carne in conflict with the military which had not kept pace with democratization and sensed a challenge to itself and to national security. Censorship and restrictions on the war correspondent tightened, until major army reforms between 1901 and 1912 brought more cordial relations between the press and the military. When the Great War broke out in 1914 the co-operative atmosphere broke down as censorship was reinstated, more severely than before. It challenged the freedom of the press and the right of the people to know. Gibbs was determined that the people should have access to news from the front. He fought hard for that objective and was instrumental in the compromise reached between the military and the press when an officially recognized system was devised for press representation on the Western Front. The wisdom of such a move was shown by the success of Philip Gibbs' war correspondence, which had appeal to a mass readership in its own language and with subjects of interest to it.
- Full Text:
- Date Issued: 1985
- Authors: Woodward, Christina Anna
- Date: 1985
- Subjects: Gibbs, Philip, 1877-1962 , War correspondents , War -- Press coverage , Mass media and war , Journalists
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2577 , http://hdl.handle.net/10962/d1003126 , Gibbs, Philip, 1877-1962 , War correspondents , War -- Press coverage , Mass media and war , Journalists
- Description: The process of democratization which appeared in the nineteenth century was partly responsible for the emergence of a mass readership. It consisted of the new urban population which had its own tastes and interests, intellectual capacity and purchasing power. The popular press was firmly established by 1900 and it radically altered the scope and style of daily journalism in its attempt to speak in the language of the majority. Philip Gibbs was one of the prominent journalists between 1900 and 1914. His aspiration to become a war correspondent stemmed from the image of the war correspondent as a figure of romance and adventure, the consequence of the militarist spirit of the age and the licence which granted him freedom of movement. Inevitably, the war correspondent carne in conflict with the military which had not kept pace with democratization and sensed a challenge to itself and to national security. Censorship and restrictions on the war correspondent tightened, until major army reforms between 1901 and 1912 brought more cordial relations between the press and the military. When the Great War broke out in 1914 the co-operative atmosphere broke down as censorship was reinstated, more severely than before. It challenged the freedom of the press and the right of the people to know. Gibbs was determined that the people should have access to news from the front. He fought hard for that objective and was instrumental in the compromise reached between the military and the press when an officially recognized system was devised for press representation on the Western Front. The wisdom of such a move was shown by the success of Philip Gibbs' war correspondence, which had appeal to a mass readership in its own language and with subjects of interest to it.
- Full Text:
- Date Issued: 1985
Sex ratios of Coccophagus atratus compere (Hymenoptera:Aphelinidae) in relation to host availability
- Authors: Donaldson, John Sydney
- Date: 1985
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5632 , http://hdl.handle.net/10962/d1004933
- Description: The mode of sex determination in most Hymenoptera is that of arrhenotokous parthenogenesis, i.e. females originate from fertilised eggs and males develop parthenogenetically from unfertilised ones. Females can therefore determine the sex of each of their offspring by controlling fertilisation. This has led to much speculation about the factors that govern hymenopteran sex ratios. Many sex ratio theories predict that solitary Hymenoptera should produce male and female offspring in a ratio of 1:1. The limited data available on sex ratios in solitary Hymenoptera does not support this prediction. However, for various reasons, data may not be representative and few detailed studies have been done. The purpose of this study was, therefore, to examine sex ratios of Coccophagus atratus, a solitary hymenopteran parasitoid, to determine whether sex ratios in this species approach 1: 1. C. atratus is a suitable species for sex ratio studies because male and female eggs are deposited in different hosts. The sex of deposited eggs can, therefore, be determined at oviposition. This eliminates any possible effects of differential mortality. Laboratory experiments were designed to determine whether C. atratus females deposit male and female eggs in fixed proportions or in a set sequence. In addition, samples of hosts were collected from the field to assess C. atratus sex ratios under natural conditions. Results show that C. atratus females do not produce sex ratios that approach 1:1 and male and female eggs are not deposited in a set sequence. Sex ratios are variable and appear to be related to the relative abundance of hosts suitable for female development and for male development. These results are discussed in relation to current sex ratio theories.
- Full Text:
- Date Issued: 1985
Sex ratios of Coccophagus atratus compere (Hymenoptera:Aphelinidae) in relation to host availability
- Authors: Donaldson, John Sydney
- Date: 1985
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5632 , http://hdl.handle.net/10962/d1004933
- Description: The mode of sex determination in most Hymenoptera is that of arrhenotokous parthenogenesis, i.e. females originate from fertilised eggs and males develop parthenogenetically from unfertilised ones. Females can therefore determine the sex of each of their offspring by controlling fertilisation. This has led to much speculation about the factors that govern hymenopteran sex ratios. Many sex ratio theories predict that solitary Hymenoptera should produce male and female offspring in a ratio of 1:1. The limited data available on sex ratios in solitary Hymenoptera does not support this prediction. However, for various reasons, data may not be representative and few detailed studies have been done. The purpose of this study was, therefore, to examine sex ratios of Coccophagus atratus, a solitary hymenopteran parasitoid, to determine whether sex ratios in this species approach 1: 1. C. atratus is a suitable species for sex ratio studies because male and female eggs are deposited in different hosts. The sex of deposited eggs can, therefore, be determined at oviposition. This eliminates any possible effects of differential mortality. Laboratory experiments were designed to determine whether C. atratus females deposit male and female eggs in fixed proportions or in a set sequence. In addition, samples of hosts were collected from the field to assess C. atratus sex ratios under natural conditions. Results show that C. atratus females do not produce sex ratios that approach 1:1 and male and female eggs are not deposited in a set sequence. Sex ratios are variable and appear to be related to the relative abundance of hosts suitable for female development and for male development. These results are discussed in relation to current sex ratio theories.
- Full Text:
- Date Issued: 1985