Improvement of fertility and hatchability of artificially incubated ostrich eggs in the little Karoo
- Van Schalkwyk, Salmon Jacobus
- Authors: Van Schalkwyk, Salmon Jacobus
- Date: 1998
- Subjects: Ostrich farming -- South Africa , Eggs -- Hatchability , Eggs -- Incubation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5713 , http://hdl.handle.net/10962/d1005399
- Description: Ostriches are an important commercial species in South Africa and are becoming increasingly so in other parts of the world. Fertility and hatchability of artificially incubated ostrich eggs, however, is generally regarded as low compared to other poultry species and to ostriches in the wild. Investigation into specific farming practices at present indicated scope for an overall improvement in productivity through a sound breeding strategy. This thesis investigated factors that affect egg production, fertility, and hatchability of artificially incubated eggs in the Little Karoo region of South Africa. Specific breeding pair combinations accounted for the major variations in egg weight, hatchability, chick production and offspring weight at slaughter age. An appreciable proportion of variation in reproductive traits was attributable to the repeatable nature of breeding pair performance from year to year, even from first breeding attempts, suggesting that selection of good breeding stock can be made from an early age. Artificially incubated eggs showed improved hatchability when eggs were collected two to three hours after lay rather than the following morning. Storing position of eggs did not significantly effect hatchability when eggs were stored for a maximum of one week. The critical zero temperature for ostrich eggs, below which no embryonical development takes place, was found to be ± 25°C and cooling eggs to temperatures below 20°C for complete cessation of embryonic development during storage resulted in better hatchabilities compared to eggs stored at 25°C room temperature. Hatchability decreased when incubator temperatures were raised from 36 to 37.3°C. Large temperature fluctuations and gradients, which encompass detrimental temperatures, persist within forced draught wooden incubators of the type most commonly in use in the Little Karoo region. The highest temperatures occurred at the top of these incubators and will consequently have a negative impact on hatchability. The ontogeny of ostrich egg metabolism showed an exponential increase during the first 70% of incubation followed by a decline to 75% of the peak value between days 31 and 38 of incubation. From peak levels of embryonic development it was calculated that single stage incubators needs an airflow of 54.4 1/egg.hour to maintain oxygen levels just below 21% and carbon dioxide levels below 0.5%. Lower embryonic mortalities were observed when eggs were turned twenty-four times/day in an electronic incubator compared to hand turning twice a day. Eggs rotated through increasing angles between 60 and 90° resulted in a linear improvement in hatchability. In incubators where turning angles were fixed at 60°, lower hatchabilities were overcome by incubating eggs for 2 - 3 weeks in a horizontal position before placing them vertically. No specific farming practice could be singled out as the main cause of low fertility or hatchability but rather a combination of certain practices applied wrongly.
- Full Text:
- Date Issued: 1998
Improvement of fertility and hatchability of artificially incubated ostrich eggs in the little Karoo
- Authors: Van Schalkwyk, Salmon Jacobus
- Date: 1998
- Subjects: Ostrich farming -- South Africa , Eggs -- Hatchability , Eggs -- Incubation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5713 , http://hdl.handle.net/10962/d1005399
- Description: Ostriches are an important commercial species in South Africa and are becoming increasingly so in other parts of the world. Fertility and hatchability of artificially incubated ostrich eggs, however, is generally regarded as low compared to other poultry species and to ostriches in the wild. Investigation into specific farming practices at present indicated scope for an overall improvement in productivity through a sound breeding strategy. This thesis investigated factors that affect egg production, fertility, and hatchability of artificially incubated eggs in the Little Karoo region of South Africa. Specific breeding pair combinations accounted for the major variations in egg weight, hatchability, chick production and offspring weight at slaughter age. An appreciable proportion of variation in reproductive traits was attributable to the repeatable nature of breeding pair performance from year to year, even from first breeding attempts, suggesting that selection of good breeding stock can be made from an early age. Artificially incubated eggs showed improved hatchability when eggs were collected two to three hours after lay rather than the following morning. Storing position of eggs did not significantly effect hatchability when eggs were stored for a maximum of one week. The critical zero temperature for ostrich eggs, below which no embryonical development takes place, was found to be ± 25°C and cooling eggs to temperatures below 20°C for complete cessation of embryonic development during storage resulted in better hatchabilities compared to eggs stored at 25°C room temperature. Hatchability decreased when incubator temperatures were raised from 36 to 37.3°C. Large temperature fluctuations and gradients, which encompass detrimental temperatures, persist within forced draught wooden incubators of the type most commonly in use in the Little Karoo region. The highest temperatures occurred at the top of these incubators and will consequently have a negative impact on hatchability. The ontogeny of ostrich egg metabolism showed an exponential increase during the first 70% of incubation followed by a decline to 75% of the peak value between days 31 and 38 of incubation. From peak levels of embryonic development it was calculated that single stage incubators needs an airflow of 54.4 1/egg.hour to maintain oxygen levels just below 21% and carbon dioxide levels below 0.5%. Lower embryonic mortalities were observed when eggs were turned twenty-four times/day in an electronic incubator compared to hand turning twice a day. Eggs rotated through increasing angles between 60 and 90° resulted in a linear improvement in hatchability. In incubators where turning angles were fixed at 60°, lower hatchabilities were overcome by incubating eggs for 2 - 3 weeks in a horizontal position before placing them vertically. No specific farming practice could be singled out as the main cause of low fertility or hatchability but rather a combination of certain practices applied wrongly.
- Full Text:
- Date Issued: 1998
In search of the culture of links : the use of myth and ritual in the work of Peter Brook
- Authors: Du Plessis, Tanya Lenore
- Date: 1998
- Subjects: Brook, Peter -- Criticism and interpretation , Myth in literature , Mahābhārata -- Adaptations , Ritual in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2136 , http://hdl.handle.net/10962/d1002368 , Brook, Peter -- Criticism and interpretation , Myth in literature , Mahābhārata -- Adaptations , Ritual in literature
- Description: This thesis examines the use of elements of myth and ritual in the work of Peter Brook, focusing primarily on The Mahabharata ( 1986 ). The argument proposes that Brook uses myth and ritual as an integral part of his search for the culture of links .. This thesis examines the precise functioning of myth and ritual in Brook's theatre, and places his work in relation to the concepts of interculturalism and postmodernism. In so doing, The Mahabharata is seen as a valid and important step in Brook's search for the culture of links. Chapter One formulates broad-based concepts of myth and ritual, and examines their function in society and culture, as well as their role in theatre. Chapter Two offers a brief discussion of the use of elements of myth and ritual in Brook's productions, beginning with King Lear (1962), and ending with 0rghast (1971). The discussion illustrates the multiple functions which myth and ritual serve in Brook's work. Chapter Three examines the trend of interculturalism, placing Brook's work within this franlework. Attention is given to the moral and political issues implicit in interculturalism. The chapter highlights the need for intercultural theatre to be evaluated in terms of artistic criteria, rather than on anthropological or political grounds. Finally, there is a discussion of the work of other intercultural theatre practitioners. Chapter Four examines Brook's Mahabharata. A detailed discussion of the authenticity and visual presentation of Brook's interpretation shows how Brook mediates between the Indian epic and a Western audience An examination of the critical response offers insights into the dangers of insensitive cross-cultural contact.. Chapter Five offers a critical summary of the argument. Brook's search for the culture of links has led him to use elements of myths and rituals of non-Western cultures. In so doing, Brook seeks to bring their living quality to his work, and to forge links between the peoples and cultures of the world.
- Full Text:
- Date Issued: 1998
- Authors: Du Plessis, Tanya Lenore
- Date: 1998
- Subjects: Brook, Peter -- Criticism and interpretation , Myth in literature , Mahābhārata -- Adaptations , Ritual in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2136 , http://hdl.handle.net/10962/d1002368 , Brook, Peter -- Criticism and interpretation , Myth in literature , Mahābhārata -- Adaptations , Ritual in literature
- Description: This thesis examines the use of elements of myth and ritual in the work of Peter Brook, focusing primarily on The Mahabharata ( 1986 ). The argument proposes that Brook uses myth and ritual as an integral part of his search for the culture of links .. This thesis examines the precise functioning of myth and ritual in Brook's theatre, and places his work in relation to the concepts of interculturalism and postmodernism. In so doing, The Mahabharata is seen as a valid and important step in Brook's search for the culture of links. Chapter One formulates broad-based concepts of myth and ritual, and examines their function in society and culture, as well as their role in theatre. Chapter Two offers a brief discussion of the use of elements of myth and ritual in Brook's productions, beginning with King Lear (1962), and ending with 0rghast (1971). The discussion illustrates the multiple functions which myth and ritual serve in Brook's work. Chapter Three examines the trend of interculturalism, placing Brook's work within this franlework. Attention is given to the moral and political issues implicit in interculturalism. The chapter highlights the need for intercultural theatre to be evaluated in terms of artistic criteria, rather than on anthropological or political grounds. Finally, there is a discussion of the work of other intercultural theatre practitioners. Chapter Four examines Brook's Mahabharata. A detailed discussion of the authenticity and visual presentation of Brook's interpretation shows how Brook mediates between the Indian epic and a Western audience An examination of the critical response offers insights into the dangers of insensitive cross-cultural contact.. Chapter Five offers a critical summary of the argument. Brook's search for the culture of links has led him to use elements of myths and rituals of non-Western cultures. In so doing, Brook seeks to bring their living quality to his work, and to forge links between the peoples and cultures of the world.
- Full Text:
- Date Issued: 1998
Managing natural resources in a rural settlement in Peddie district
- Authors: Ainslie, Andrew
- Date: 1998
- Subjects: Conservation of natural resources -- South Africa -- Management , Natural resources -- South Africa -- Peddie District -- Management , Peddie (South Africa) -- Social conditions , Peddie (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2110 , http://hdl.handle.net/10962/d1007462 , Conservation of natural resources -- South Africa -- Management , Natural resources -- South Africa -- Peddie District -- Management , Peddie (South Africa) -- Social conditions , Peddie (South Africa) -- History
- Description: This thesis is an account of the challenges people in Tyefu Location, Peddie District, and specifically in Gwabeni village, face in their attempts to manage their common pool natural resources. Taking my analytical cue from the literature which deals with the institutional dimensions of resource management in common property systems, I look at the impact of both outside influences and local dynamics on resource managing institutions at village level. I show how particular historical circumstances, including state interventions, led to the enclosure of Tyefu Location, and to the rapid increase in the population that had to be accommodated here. This placed enormous pressure on the natural resources of the area, and contributed to the emasculation of the local institutions responsible for overseeing resource management. The residents of the location adopted whatever strategies they could to ameliorate the depletion of natural resources in their villages. One 'traditional' strategy they have sought to emulate is to move their imizi (homesteads) away from areas where local resources has been exhausted. Given the finite area of land available to them, this strategy was only ever likely to be successful in the short-term. I analyse social, economic and institutional factors at village level that appear to act as disincentives to collective resource management activities. These factors include the social structure of the imizi and the socio-economic heterogeneity that exists between imizi in Gwabeni village. The varying degrees of household economic marginality that follow from this, together with the differential ownership of livestock and other possessions that decrease people's reliance on locally available natural resources, mean that the transaction costs that people would incur by contributing to collective resource management activities, differ widely. A primary cause of people's failure to engage in resource management at village level stems from the dispersion of the members of their imizi. This factor robs the village of decision makers and undermines the capacity of those left behind to make and implement resource management decisions. It results in the various members of imizi in the village having different orientations that dissipate the energy needed for collective action. It also fuels existing struggles, and creates new ones, over the meanings and uses of the term 'community'. I conclude by arguing that, in Tyefu Location, the management of natural resources is extremely difficult to co-ordinate, because such management is highly contested, undermined by differentiation among resource users, and subject to the attentions of weak village institutions that do not share a clear set of resource management objectives. , KMBT_363
- Full Text:
- Date Issued: 1998
- Authors: Ainslie, Andrew
- Date: 1998
- Subjects: Conservation of natural resources -- South Africa -- Management , Natural resources -- South Africa -- Peddie District -- Management , Peddie (South Africa) -- Social conditions , Peddie (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2110 , http://hdl.handle.net/10962/d1007462 , Conservation of natural resources -- South Africa -- Management , Natural resources -- South Africa -- Peddie District -- Management , Peddie (South Africa) -- Social conditions , Peddie (South Africa) -- History
- Description: This thesis is an account of the challenges people in Tyefu Location, Peddie District, and specifically in Gwabeni village, face in their attempts to manage their common pool natural resources. Taking my analytical cue from the literature which deals with the institutional dimensions of resource management in common property systems, I look at the impact of both outside influences and local dynamics on resource managing institutions at village level. I show how particular historical circumstances, including state interventions, led to the enclosure of Tyefu Location, and to the rapid increase in the population that had to be accommodated here. This placed enormous pressure on the natural resources of the area, and contributed to the emasculation of the local institutions responsible for overseeing resource management. The residents of the location adopted whatever strategies they could to ameliorate the depletion of natural resources in their villages. One 'traditional' strategy they have sought to emulate is to move their imizi (homesteads) away from areas where local resources has been exhausted. Given the finite area of land available to them, this strategy was only ever likely to be successful in the short-term. I analyse social, economic and institutional factors at village level that appear to act as disincentives to collective resource management activities. These factors include the social structure of the imizi and the socio-economic heterogeneity that exists between imizi in Gwabeni village. The varying degrees of household economic marginality that follow from this, together with the differential ownership of livestock and other possessions that decrease people's reliance on locally available natural resources, mean that the transaction costs that people would incur by contributing to collective resource management activities, differ widely. A primary cause of people's failure to engage in resource management at village level stems from the dispersion of the members of their imizi. This factor robs the village of decision makers and undermines the capacity of those left behind to make and implement resource management decisions. It results in the various members of imizi in the village having different orientations that dissipate the energy needed for collective action. It also fuels existing struggles, and creates new ones, over the meanings and uses of the term 'community'. I conclude by arguing that, in Tyefu Location, the management of natural resources is extremely difficult to co-ordinate, because such management is highly contested, undermined by differentiation among resource users, and subject to the attentions of weak village institutions that do not share a clear set of resource management objectives. , KMBT_363
- Full Text:
- Date Issued: 1998
Media reach and reception in development communication: the case of the Rural Industries Innovation Centre in Botswana
- Authors: Maleke, Jackson Mogopodi
- Date: 1998
- Subjects: Rural Industries Innovation Centre (Kanye, Botswana) , Communication in rural development , Mass media in community development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3455 , http://hdl.handle.net/10962/d1002909 , Rural Industries Innovation Centre (Kanye, Botswana) , Communication in rural development , Mass media in community development
- Description: The study was conducted in Phitshane-Molopo in Botswana. Phitshane-Molopo is located about 115 kilometers south of the main village of Kanye in which the Rural Industries Innovation Centre operates. The study constitutes the first attempt at evaluating audience reach and reception of the RIIC media messages. In this study, a sample of 50 representatives of households (the rationale is covered in chapter 1) was taken, for which a questionnaire was administered, including conducting in-depth interviews with key informants. The study found that RIlC media are not reaching the audience in keeping with the corporate goals and assumptions on the basis of which the communication strategy was established. The audience has claimed that the print media relayed to them through the extension officer channel do not reach them. The study also found that the audience possessed adequate literacy skills and the majority of them could read materials produced in Setswana. Only a few individuals preferred media text produced in the English language. The study therefore deplores RIIC's proclivity towards producing its media texts only in the English language. This has tended to marginalise members of the audience who cannot read in English. It is thus hoped that this study would provide a learning experience for RIIC to consider producing its communication media in relation to the needs of the audience. The study also found that the impact of the RIIC radio programme is very poor, with only a low of 2% of the sample population having listened to this programme. The problem stems from the poor Radio Botswana transmission system. The audience said that for the larger part of the day, they can't get Radio Botswana on air. As a result, they have shifted their interest to the South African radio stations such as Radio Tswana and Radio Mmabatho, which are constantly on air. The study concludes that the RIIC communication strategy is failing in the study area because the paradigm in which it is located is somewhat flawed, as a result of which it does not effectively impact upon reach and reception. At the core of this failure rate are implementation problems and the lack of evaluation that would have picked up the - problems earlier, for which solutions would have been found. Consequently, th~$tudy recommends the need to explore the suitability and effectiveness of the indigenous media for possible syncretization with conventional media as recommended in the need based integrative model (Nwosu and Megwa: 1993). Indigenous media are ideally suited to rural communication needs because they are consistent with the socio-cultural expectations of the audience. RIIC therefore stands to benefit from these media because the bulk of its audience resides in rural areas.
- Full Text:
- Date Issued: 1998
- Authors: Maleke, Jackson Mogopodi
- Date: 1998
- Subjects: Rural Industries Innovation Centre (Kanye, Botswana) , Communication in rural development , Mass media in community development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3455 , http://hdl.handle.net/10962/d1002909 , Rural Industries Innovation Centre (Kanye, Botswana) , Communication in rural development , Mass media in community development
- Description: The study was conducted in Phitshane-Molopo in Botswana. Phitshane-Molopo is located about 115 kilometers south of the main village of Kanye in which the Rural Industries Innovation Centre operates. The study constitutes the first attempt at evaluating audience reach and reception of the RIIC media messages. In this study, a sample of 50 representatives of households (the rationale is covered in chapter 1) was taken, for which a questionnaire was administered, including conducting in-depth interviews with key informants. The study found that RIlC media are not reaching the audience in keeping with the corporate goals and assumptions on the basis of which the communication strategy was established. The audience has claimed that the print media relayed to them through the extension officer channel do not reach them. The study also found that the audience possessed adequate literacy skills and the majority of them could read materials produced in Setswana. Only a few individuals preferred media text produced in the English language. The study therefore deplores RIIC's proclivity towards producing its media texts only in the English language. This has tended to marginalise members of the audience who cannot read in English. It is thus hoped that this study would provide a learning experience for RIIC to consider producing its communication media in relation to the needs of the audience. The study also found that the impact of the RIIC radio programme is very poor, with only a low of 2% of the sample population having listened to this programme. The problem stems from the poor Radio Botswana transmission system. The audience said that for the larger part of the day, they can't get Radio Botswana on air. As a result, they have shifted their interest to the South African radio stations such as Radio Tswana and Radio Mmabatho, which are constantly on air. The study concludes that the RIIC communication strategy is failing in the study area because the paradigm in which it is located is somewhat flawed, as a result of which it does not effectively impact upon reach and reception. At the core of this failure rate are implementation problems and the lack of evaluation that would have picked up the - problems earlier, for which solutions would have been found. Consequently, th~$tudy recommends the need to explore the suitability and effectiveness of the indigenous media for possible syncretization with conventional media as recommended in the need based integrative model (Nwosu and Megwa: 1993). Indigenous media are ideally suited to rural communication needs because they are consistent with the socio-cultural expectations of the audience. RIIC therefore stands to benefit from these media because the bulk of its audience resides in rural areas.
- Full Text:
- Date Issued: 1998
Morphometrics and preliminary biology of the caridean shrimp Nauticaris marionis Bate, 1888, at the Prince Edward Islands (South Ocean), 37° 50'E, 46° 45'S
- Authors: Kuun, Patrick John
- Date: 1998
- Subjects: Shrimps -- Prince Edward Islands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5733 , http://hdl.handle.net/10962/d1005419 , Shrimps -- Prince Edward Islands
- Description: Carapace length, as the best measure of N. marionis body size, is precisely defined. It is shown that N. marionis is a partially protandric hermaphrodite. N. marionis appear to hatch just before April each year, with a little hatching persisting until May. The vast majority of juveniles develop into males. The majority of males transmutate into females in their third year. By April/May the transmutation is probably complete. Reproduction can occur before all male secondary characteristics have been lost. A small minority of individuals develop directly into females without passing through a male phase. At least some of these females can be initially recognized after they have developed mature ovaries by the presence of appendices internae on their first pleopods, a male copulatory structure which all juvenile N. marionis possess. Too few gravid females were recovered to make any statement on whether spawning can occur before this structure is lost. Such females may lose their first pleopod appendices internae in one moult, possibly just before spawning, which may be in late April/early May. Such individuals seem to mature into ovigerous females at a slightly smaller carapace length than do the majority of females which have had a male-phase past. A few females which have passed through a male phase seem to begin developing ovaries at about this small carapace length as well. Once the appendices internae have been lost there appears to be no way of identifying any given female's past life-history. It would seem that during the first year of life N. marionis survive in undetected localities, moult into juveniles, and then settle amongst the benthos from the plankton. Diurnal vertical migration then occurs up to an unknown larger size. It is not known whether the larvae are initially planktonic or not. It is possible that settling of small N. marionis onto the benthos only begins after November. Whether the appendices masculinae of some males only begin growing after they have settled Abstract XIX onto the benthos is unknown, but for the majority at least this begins whilst they are planktonic juveniles. Individuals older than five years are undetectable using samples of the sizes analyzed in this thesis, but they may well persist until quite an advanced age. Niche separation between smaller and larger N. marionis individuals may occur. Diel vertical migration may occur to some extent amongst large N. marionis. Itinerant euphausiids may contribute substantially to the maintenance of top predator populations at the archipelago, either through direct predation by those predators or via predation by N. marionis, which in turn are consumed by those predators. N. marionis itself is an opportunistic feeder, although the majority of its prey seem to be suspension feeders, both benthic and pelagic. In multisample situations, ageing of N. marionis cohorts is made less subjective if one utilizes the phenomenon of synchronized sexual inversion. The von Bertalanffy growth parameters for N. marionis are tentatively identified as k = 0.2353/year, L_ = 12.69mm, to = -0.2828 years and WW_ = 2.03g. The programme FiSAT is discussed, having been found to be extremely useful, but having also been found to have certain faults. Various hypotheses are proposed and are put forward as suggestions for future studies.
- Full Text:
- Date Issued: 1998
- Authors: Kuun, Patrick John
- Date: 1998
- Subjects: Shrimps -- Prince Edward Islands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5733 , http://hdl.handle.net/10962/d1005419 , Shrimps -- Prince Edward Islands
- Description: Carapace length, as the best measure of N. marionis body size, is precisely defined. It is shown that N. marionis is a partially protandric hermaphrodite. N. marionis appear to hatch just before April each year, with a little hatching persisting until May. The vast majority of juveniles develop into males. The majority of males transmutate into females in their third year. By April/May the transmutation is probably complete. Reproduction can occur before all male secondary characteristics have been lost. A small minority of individuals develop directly into females without passing through a male phase. At least some of these females can be initially recognized after they have developed mature ovaries by the presence of appendices internae on their first pleopods, a male copulatory structure which all juvenile N. marionis possess. Too few gravid females were recovered to make any statement on whether spawning can occur before this structure is lost. Such females may lose their first pleopod appendices internae in one moult, possibly just before spawning, which may be in late April/early May. Such individuals seem to mature into ovigerous females at a slightly smaller carapace length than do the majority of females which have had a male-phase past. A few females which have passed through a male phase seem to begin developing ovaries at about this small carapace length as well. Once the appendices internae have been lost there appears to be no way of identifying any given female's past life-history. It would seem that during the first year of life N. marionis survive in undetected localities, moult into juveniles, and then settle amongst the benthos from the plankton. Diurnal vertical migration then occurs up to an unknown larger size. It is not known whether the larvae are initially planktonic or not. It is possible that settling of small N. marionis onto the benthos only begins after November. Whether the appendices masculinae of some males only begin growing after they have settled Abstract XIX onto the benthos is unknown, but for the majority at least this begins whilst they are planktonic juveniles. Individuals older than five years are undetectable using samples of the sizes analyzed in this thesis, but they may well persist until quite an advanced age. Niche separation between smaller and larger N. marionis individuals may occur. Diel vertical migration may occur to some extent amongst large N. marionis. Itinerant euphausiids may contribute substantially to the maintenance of top predator populations at the archipelago, either through direct predation by those predators or via predation by N. marionis, which in turn are consumed by those predators. N. marionis itself is an opportunistic feeder, although the majority of its prey seem to be suspension feeders, both benthic and pelagic. In multisample situations, ageing of N. marionis cohorts is made less subjective if one utilizes the phenomenon of synchronized sexual inversion. The von Bertalanffy growth parameters for N. marionis are tentatively identified as k = 0.2353/year, L_ = 12.69mm, to = -0.2828 years and WW_ = 2.03g. The programme FiSAT is discussed, having been found to be extremely useful, but having also been found to have certain faults. Various hypotheses are proposed and are put forward as suggestions for future studies.
- Full Text:
- Date Issued: 1998
Natural resources and local management in the Hewu District of the Eastern Cape : limitations to achieving sustainability
- Authors: Nkansa-Dwamena, Yaw
- Date: 1998
- Subjects: Natural resources -- South Africa -- Management , Natural resources -- South Africa -- Eastern Cape -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4218 , http://hdl.handle.net/10962/d1003787 , Natural resources -- South Africa -- Management , Natural resources -- South Africa -- Eastern Cape -- Management
- Description: The Mceula Commonage Land in the Hewu district lies due northwest of Whittle sea and west of Queenstown in the Eastern Cape. This thesis has two main objectives. Firstly, to survey and analyse the condition of the natural resource. base in the Hewu district with particular reference to water, soil, vegetation and land use. Secondly, to investigate the relationship between scientific approaches to assessing land use degradation and to compare these to the results obtained using a participatory approach of the rural environment of the Hewu district of the Eastern Cape. Random quadrats (4m2) were sampled and corresponding line transects were done with increasing distances from the villages. The Braun-Blanquet method was used to find the cover and abundance of the various species of plants. Data obtained from point sampling along 100 metre line transects was used to assess the condition of the veld using Trollope's technique. Six communities were defined using TWINSP AN, and grazing capacities and veld condition scores of the respective sites were calculated. It was concluded that the six communities were distributed along a gradient of palatable to non palatable grass and grasslike species. Rangelands close to the villages had low veld condition scores and percentage plant cover as opposed to those farther away from the villages. The null hypothesis of no significant difference between the percentage plant cover and condition of the veld close to the villages and farther away from the villages was rejected. Whilst it is urgent to resolve political disputes around land through land distribution, a key issue for the future is sustainability of the natural resource base of South Africa. To attain this, the old traditional methods of research must be supplemented with the participatory method, where the local community becomes fully involved. The central theme of the participatory approach was to investigate the possibility of promoting local management of the natural resources. Workshops were conducted to involve the local community in the project. The community formed six discussion groups that met regularly to discuss environmental issues. The six groups that were formed were: Firewood or woodlot collectors, shepherds / livestock raisers, crop fanners / agriculturists, water collectors, building material / soil collectors and medicinal plant users. The results obtained from the meeting of the discussion groups were used to compare the scientific results obtained from Braun-Blanquet method. Perceptions about their environment, which came out of the results of the discussion groups showed that the local knowledge of the rural community of Mceula was sufficient to train them to manage their environment sustainably.
- Full Text:
- Date Issued: 1998
- Authors: Nkansa-Dwamena, Yaw
- Date: 1998
- Subjects: Natural resources -- South Africa -- Management , Natural resources -- South Africa -- Eastern Cape -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4218 , http://hdl.handle.net/10962/d1003787 , Natural resources -- South Africa -- Management , Natural resources -- South Africa -- Eastern Cape -- Management
- Description: The Mceula Commonage Land in the Hewu district lies due northwest of Whittle sea and west of Queenstown in the Eastern Cape. This thesis has two main objectives. Firstly, to survey and analyse the condition of the natural resource. base in the Hewu district with particular reference to water, soil, vegetation and land use. Secondly, to investigate the relationship between scientific approaches to assessing land use degradation and to compare these to the results obtained using a participatory approach of the rural environment of the Hewu district of the Eastern Cape. Random quadrats (4m2) were sampled and corresponding line transects were done with increasing distances from the villages. The Braun-Blanquet method was used to find the cover and abundance of the various species of plants. Data obtained from point sampling along 100 metre line transects was used to assess the condition of the veld using Trollope's technique. Six communities were defined using TWINSP AN, and grazing capacities and veld condition scores of the respective sites were calculated. It was concluded that the six communities were distributed along a gradient of palatable to non palatable grass and grasslike species. Rangelands close to the villages had low veld condition scores and percentage plant cover as opposed to those farther away from the villages. The null hypothesis of no significant difference between the percentage plant cover and condition of the veld close to the villages and farther away from the villages was rejected. Whilst it is urgent to resolve political disputes around land through land distribution, a key issue for the future is sustainability of the natural resource base of South Africa. To attain this, the old traditional methods of research must be supplemented with the participatory method, where the local community becomes fully involved. The central theme of the participatory approach was to investigate the possibility of promoting local management of the natural resources. Workshops were conducted to involve the local community in the project. The community formed six discussion groups that met regularly to discuss environmental issues. The six groups that were formed were: Firewood or woodlot collectors, shepherds / livestock raisers, crop fanners / agriculturists, water collectors, building material / soil collectors and medicinal plant users. The results obtained from the meeting of the discussion groups were used to compare the scientific results obtained from Braun-Blanquet method. Perceptions about their environment, which came out of the results of the discussion groups showed that the local knowledge of the rural community of Mceula was sufficient to train them to manage their environment sustainably.
- Full Text:
- Date Issued: 1998
New rules for security and survival: Southern Africa's adaptation to a changing world environment
- Authors: Naidoo, Sagaren Krishna
- Date: 1998
- Subjects: Internal security -- South Africa , National security -- South Africa , South Africa -- Politics and government -- 1994- , South Africa -- Economic conditions -- 1991-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2814 , http://hdl.handle.net/10962/d1003024 , Internal security -- South Africa , National security -- South Africa , South Africa -- Politics and government -- 1994- , South Africa -- Economic conditions -- 1991-
- Description: In the wake of the post-Cold War era, students of international relations were forced to review their theoretical frameworks to explain new rules for international peace and security. States are now confronted with new constraints for their security and survival as current trends in international politics depict a 'regionalisation' of peace and security. For southern Africa, likewise, the end of the Cold War and, moreover, apartheid, compels its member states to redefine their security strategies and mechanisms for survival. This thesis undertakes to examine southern Africa's adaptation to new rules of a changing world environment, to ensure a stable and secure region, into the next millennium. At the outset of this thesis lies a conceptual contextualisation of security within the major contemporary theoretical approaches of international relations. By examining the essential differences between the redefinitions and new conceptualisations of security, this thesis, firstly argues that the state in southern Africa must be retained as a primary referent of security. This argument is premised on the need to create stronger states for a 'regionalisation' of security in southern Africa. The second issue examined is the changing world environment and its impact on the state and development in Africa, as the new constraints to which the continent must adapt, for security and survival. Arguing that the new international economic order and 'globalisation' dictate the new rules, this chapter asserts that the 'weak' states in Africa need to be strengthened to have the necessary capacity to be the means for its people's security. Finally this thesis examines the new rules for southern Africa's adaptation to a changing world environment. The new rules for the African sub-continent involve the formation of a security regime and economic community with, the power-house, South Africa. Using the Southern African Development Community(SADC) as the umbrella body, the formation of the Organ for Politics, Defence and Security, and signing of trade protocols for a movement towards a free trade area, are evidence of southern Africa's attempts to adapt to new rules for its security. Such adaptation cannot, however, be accomplished with 'weak' states. Southern African states will have to, therefore, be strengthened to attain a more secure adaptation to the new international (economic) order.
- Full Text:
- Date Issued: 1998
- Authors: Naidoo, Sagaren Krishna
- Date: 1998
- Subjects: Internal security -- South Africa , National security -- South Africa , South Africa -- Politics and government -- 1994- , South Africa -- Economic conditions -- 1991-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2814 , http://hdl.handle.net/10962/d1003024 , Internal security -- South Africa , National security -- South Africa , South Africa -- Politics and government -- 1994- , South Africa -- Economic conditions -- 1991-
- Description: In the wake of the post-Cold War era, students of international relations were forced to review their theoretical frameworks to explain new rules for international peace and security. States are now confronted with new constraints for their security and survival as current trends in international politics depict a 'regionalisation' of peace and security. For southern Africa, likewise, the end of the Cold War and, moreover, apartheid, compels its member states to redefine their security strategies and mechanisms for survival. This thesis undertakes to examine southern Africa's adaptation to new rules of a changing world environment, to ensure a stable and secure region, into the next millennium. At the outset of this thesis lies a conceptual contextualisation of security within the major contemporary theoretical approaches of international relations. By examining the essential differences between the redefinitions and new conceptualisations of security, this thesis, firstly argues that the state in southern Africa must be retained as a primary referent of security. This argument is premised on the need to create stronger states for a 'regionalisation' of security in southern Africa. The second issue examined is the changing world environment and its impact on the state and development in Africa, as the new constraints to which the continent must adapt, for security and survival. Arguing that the new international economic order and 'globalisation' dictate the new rules, this chapter asserts that the 'weak' states in Africa need to be strengthened to have the necessary capacity to be the means for its people's security. Finally this thesis examines the new rules for southern Africa's adaptation to a changing world environment. The new rules for the African sub-continent involve the formation of a security regime and economic community with, the power-house, South Africa. Using the Southern African Development Community(SADC) as the umbrella body, the formation of the Organ for Politics, Defence and Security, and signing of trade protocols for a movement towards a free trade area, are evidence of southern Africa's attempts to adapt to new rules for its security. Such adaptation cannot, however, be accomplished with 'weak' states. Southern African states will have to, therefore, be strengthened to attain a more secure adaptation to the new international (economic) order.
- Full Text:
- Date Issued: 1998
Preliminary investigation of the molecular pathogenicity determinants of Xanthomonas campestris pv. zeae
- Authors: Downing, T G
- Date: 1998
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4066 , http://hdl.handle.net/10962/d1004922
- Description: Xanthomonas campestris pv. zeae was shown to posses a vast range of potential plant cell wall degrading enzymes including at least one protease, a carboxymethylcellulase, pectin lyase, polygalacturonase and a B-endoglucanase. Replicon stability and transfer system efficiencies were determined for a range of oriC, and oriT -tra combinations, and suitable vectors were constructed and identified for insertional inactivation by homologous recombination. Ideal suicide replicons were found to be pACYC184 and p15A, while P, Wand Q group replicons were supported by X campestris pv. zeae. Group P and group N transfer systems were shown to be highly efficient in intra-genus matings between Escherichia coli and X campestris pv. zeae, with the exception of P-tra systems in trans for the delivery of Tn5. Various cloning vectors were tested for stability and mobility. Tn5 was shown to transpose at high frequencies into the genome of the bacterial plant pathogen, and insertion was relatively random. Suitable screening assays were established to allow rapid isolation of mutants with potential virulence or pathogenic deviations, after mutagenesis. Two non-pathogenic mutants were identified, one of which was a putative hrp·, while the other was a leaky virulence. A single mutant showing 40% reduced protease activity was also shown to exhibit reduced virulence indicating a minor role for the protease in pathogenicity. The majority of virulence mutants showed altered growth in different levels of nutritional availability and complexity. Nutritional viability (the ability to acquire and use nutrients at a sufficient rate to grow fast enough to overcome host defences) was shown to be essential for virulence and possibly pathogenicity. Wild-type in-planta behaviour was analysed and growth and spread patterns typical for pathogenic response identified. Chief amongst these was the requirement for a threshold level of cells per leaf area or length, before symptoms could develop. Occlusion of vascular bundles was shown not to be the primary factor in the pathogenicity of X campestris pv. zeae. Threshold levels for lesion development indicate the absence of a diffusable lesion forming element, and possibly the requirement of cell density for induction of certain functions. , KMBT_363
- Full Text:
- Date Issued: 1998
- Authors: Downing, T G
- Date: 1998
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4066 , http://hdl.handle.net/10962/d1004922
- Description: Xanthomonas campestris pv. zeae was shown to posses a vast range of potential plant cell wall degrading enzymes including at least one protease, a carboxymethylcellulase, pectin lyase, polygalacturonase and a B-endoglucanase. Replicon stability and transfer system efficiencies were determined for a range of oriC, and oriT -tra combinations, and suitable vectors were constructed and identified for insertional inactivation by homologous recombination. Ideal suicide replicons were found to be pACYC184 and p15A, while P, Wand Q group replicons were supported by X campestris pv. zeae. Group P and group N transfer systems were shown to be highly efficient in intra-genus matings between Escherichia coli and X campestris pv. zeae, with the exception of P-tra systems in trans for the delivery of Tn5. Various cloning vectors were tested for stability and mobility. Tn5 was shown to transpose at high frequencies into the genome of the bacterial plant pathogen, and insertion was relatively random. Suitable screening assays were established to allow rapid isolation of mutants with potential virulence or pathogenic deviations, after mutagenesis. Two non-pathogenic mutants were identified, one of which was a putative hrp·, while the other was a leaky virulence. A single mutant showing 40% reduced protease activity was also shown to exhibit reduced virulence indicating a minor role for the protease in pathogenicity. The majority of virulence mutants showed altered growth in different levels of nutritional availability and complexity. Nutritional viability (the ability to acquire and use nutrients at a sufficient rate to grow fast enough to overcome host defences) was shown to be essential for virulence and possibly pathogenicity. Wild-type in-planta behaviour was analysed and growth and spread patterns typical for pathogenic response identified. Chief amongst these was the requirement for a threshold level of cells per leaf area or length, before symptoms could develop. Occlusion of vascular bundles was shown not to be the primary factor in the pathogenicity of X campestris pv. zeae. Threshold levels for lesion development indicate the absence of a diffusable lesion forming element, and possibly the requirement of cell density for induction of certain functions. , KMBT_363
- Full Text:
- Date Issued: 1998
Raptor communities in hill habitats in south-eastern Zimbabwe
- Authors: Davison, Bruce
- Date: 1998
- Subjects: Birds of prey -- Zimbabwe , Birds of prey -- Ecology -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5751 , http://hdl.handle.net/10962/d1005438 , Birds of prey -- Zimbabwe , Birds of prey -- Ecology -- Zimbabwe
- Description: The interrelationships between species composition, resource-use and availability, breeding and competition were studied in two hill habitat raptor communities in a conserved reserve and an unprotected communal land in Zimbabwe in 1995 and 1996. The conserved Lonestar Study Area (LSA) and the unprotected Communal Land Study area (CLSA) had 38 and 31 raptor species, high and normal diversities for the area sizes respectively. An estimated 147 pairs of 21 raptor species bred in 40km² in the LSA compared to only 26 pairs of 22 raptor species per 40km² in the CLSA. Six species (African Hawk Eagle Hieraaetus spilogaster, Black Eagle Aquila verreauxii, Crowned Eagle Stephanoaetus coronatus, Little Banded Goshawk Accipiter badius, Barn Owl Tyto alba,and Barred Owl Glancidium capense made up 69% of breeding raptors in the LSA, while African Hawk Eagles, Little Banded Goshawks, Barn Owls and Barred Owls made up 58% of the breeding raptors in the CLSA. The abundance of Black, Crowned and African Hawk Eagles in the LSA was linked to abundant hyrax, Heterohyrax brucei and Procavia capensis and juvenile bushbuck Tragelaphus prey, and the high reproduction rates of Natal Francolin Francolinus natalensis (0.7 per ha when not breeding). Little Banded Goshawk and Barn Owl abundances were linked to their ability to change prey preferences according to prey availability. A fairly high rate of breeding attempts by eagles in the LSA in both years (60 - 76% of all pairs per year)was probably also linked to prey abundance, Most breeding failures were predator related, and were more common in areas of relatively low nesting densities indicating lower parental vigilance there. High eagle breeding densities were associated with small mean territory sizes in the LSA (7.7 - 10.7km² for the main eagle species). Eagles in the LSA usually nested closer to another eagle species than a conspecific, resulting in regular distributions of nests and no territory overlap within species. Differences in daily flight activity of eagles in both study areas, and in the onset of breeding between LSA eagles probably reduced interspecific aggression. Interspecific competition food and nest sites amongst LSA eagles was possibly lessened by slight ditferences in resource selection. Raptor resources were mostly unaffected by human activities in either study area during the study period. Differences in the raptor communities were probably as a result of natural habitat differences. The CLSA raptors potentially face resource loss through forest clearing and hunting. An expansion of the present CAMPFIRE program will protect the CLSA raptors.
- Full Text:
- Date Issued: 1998
- Authors: Davison, Bruce
- Date: 1998
- Subjects: Birds of prey -- Zimbabwe , Birds of prey -- Ecology -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5751 , http://hdl.handle.net/10962/d1005438 , Birds of prey -- Zimbabwe , Birds of prey -- Ecology -- Zimbabwe
- Description: The interrelationships between species composition, resource-use and availability, breeding and competition were studied in two hill habitat raptor communities in a conserved reserve and an unprotected communal land in Zimbabwe in 1995 and 1996. The conserved Lonestar Study Area (LSA) and the unprotected Communal Land Study area (CLSA) had 38 and 31 raptor species, high and normal diversities for the area sizes respectively. An estimated 147 pairs of 21 raptor species bred in 40km² in the LSA compared to only 26 pairs of 22 raptor species per 40km² in the CLSA. Six species (African Hawk Eagle Hieraaetus spilogaster, Black Eagle Aquila verreauxii, Crowned Eagle Stephanoaetus coronatus, Little Banded Goshawk Accipiter badius, Barn Owl Tyto alba,and Barred Owl Glancidium capense made up 69% of breeding raptors in the LSA, while African Hawk Eagles, Little Banded Goshawks, Barn Owls and Barred Owls made up 58% of the breeding raptors in the CLSA. The abundance of Black, Crowned and African Hawk Eagles in the LSA was linked to abundant hyrax, Heterohyrax brucei and Procavia capensis and juvenile bushbuck Tragelaphus prey, and the high reproduction rates of Natal Francolin Francolinus natalensis (0.7 per ha when not breeding). Little Banded Goshawk and Barn Owl abundances were linked to their ability to change prey preferences according to prey availability. A fairly high rate of breeding attempts by eagles in the LSA in both years (60 - 76% of all pairs per year)was probably also linked to prey abundance, Most breeding failures were predator related, and were more common in areas of relatively low nesting densities indicating lower parental vigilance there. High eagle breeding densities were associated with small mean territory sizes in the LSA (7.7 - 10.7km² for the main eagle species). Eagles in the LSA usually nested closer to another eagle species than a conspecific, resulting in regular distributions of nests and no territory overlap within species. Differences in daily flight activity of eagles in both study areas, and in the onset of breeding between LSA eagles probably reduced interspecific aggression. Interspecific competition food and nest sites amongst LSA eagles was possibly lessened by slight ditferences in resource selection. Raptor resources were mostly unaffected by human activities in either study area during the study period. Differences in the raptor communities were probably as a result of natural habitat differences. The CLSA raptors potentially face resource loss through forest clearing and hunting. An expansion of the present CAMPFIRE program will protect the CLSA raptors.
- Full Text:
- Date Issued: 1998
Reproductive behaviour of the skunk clownfish, Amphiprion akallopisos, under captive conditions
- Authors: Haschick, Rory Dean
- Date: 1998
- Subjects: Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5316 , http://hdl.handle.net/10962/d1005161 , Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
- Description: The objectives of the study were to determine whether or not behaviour could be used to predict spawning in Amphiprion akallopisos, and to document the behaviour of this species under various environmental conditions in captivity. The spawning behaviour of A. akallopisos was studied and quantified. Three behaviour patterns - belly touching, nest cleaning by the female and mutual nest cleaning (by the male and the female) were identified as predictors for spawning. The reproductive behaviour of A.akallopisos under three photoperiods was investigated. The photoperiods were: 14L:10D, 10hr15minL:13hr45minD and a natural photoperiod cycle condensed into three months. A. akallopisos maintained under 14 L:10D exhibited a significantly higher frequency and duration of chasing, nest cleaning and total interaction compared to fish kept under 10hr15minL:13hr45minD. A photoperiod of 14L:10D was selected for further studies. As manipulation of photoperiod did not induce spawning, GnRHa was administered to the fish in the diet at levels of 10, 20, 40 and 80 μg/kg BW. Control groups were fed untreated food. None of the dosages were successful in inducing spawning, or spawning behaviour in A. akallopisos. It is possible that the method of hormone application was not suitable for this species. It is also possible that behaviour may regulate blood hormone levels as opposed to endocrine status influencing behaviour. In the third trial, A. akallopisos was maintained with, and without sea anemones in order to determine whether or not anemone hosts are necessary for spawning. The presence of anemones did not induce spawning and A. akallopisos kept without anemones exhibited significantly more interactive behaviour than fish kept with hosts. Spawning of A. akallopisos at a later date without anemones suggests that anemones are not necessary for spawning in A. akallopisos. Light intensity was investigated as a cue for spawning. The reproductive behaviour of A. akallopisos was then studied under light intensities of 4.16 x 10¹⁵ quanta.sec⁻¹.cm⁻², 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻² and this intensity plus natural light. Spawning occurred mainly under 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻². Fish maintained under this light intensity exhibited significantly more of nest cleaning behaviour in terms of frequency and duration than fish maintained under low light intensity. A minimum light intensity of 8.85 x 10¹⁵ quanta. sec⁻¹.cm⁻² is recommended for conditioning of this species. This study can be of practical relevance to hatchery managers who can use the methods developed and record predictors for spawning in A. akallopisos and other Amphiprion species. In this way imminence of spawning may be estimated. Most importantly, the study also has academic merit as little work has been undertaken in this field. Although the observational method used in this study was adequate for the purposes of the investigation, future work of this nature should incorporate other methods of documenting gonadal development such as gonadal staging and GSI in order to obtain more conclusive results.
- Full Text:
- Date Issued: 1998
- Authors: Haschick, Rory Dean
- Date: 1998
- Subjects: Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5316 , http://hdl.handle.net/10962/d1005161 , Anemonefishes -- Spawning , Amphiprion -- Reproduction , Fishes -- Reproduction , Hatchery fishes
- Description: The objectives of the study were to determine whether or not behaviour could be used to predict spawning in Amphiprion akallopisos, and to document the behaviour of this species under various environmental conditions in captivity. The spawning behaviour of A. akallopisos was studied and quantified. Three behaviour patterns - belly touching, nest cleaning by the female and mutual nest cleaning (by the male and the female) were identified as predictors for spawning. The reproductive behaviour of A.akallopisos under three photoperiods was investigated. The photoperiods were: 14L:10D, 10hr15minL:13hr45minD and a natural photoperiod cycle condensed into three months. A. akallopisos maintained under 14 L:10D exhibited a significantly higher frequency and duration of chasing, nest cleaning and total interaction compared to fish kept under 10hr15minL:13hr45minD. A photoperiod of 14L:10D was selected for further studies. As manipulation of photoperiod did not induce spawning, GnRHa was administered to the fish in the diet at levels of 10, 20, 40 and 80 μg/kg BW. Control groups were fed untreated food. None of the dosages were successful in inducing spawning, or spawning behaviour in A. akallopisos. It is possible that the method of hormone application was not suitable for this species. It is also possible that behaviour may regulate blood hormone levels as opposed to endocrine status influencing behaviour. In the third trial, A. akallopisos was maintained with, and without sea anemones in order to determine whether or not anemone hosts are necessary for spawning. The presence of anemones did not induce spawning and A. akallopisos kept without anemones exhibited significantly more interactive behaviour than fish kept with hosts. Spawning of A. akallopisos at a later date without anemones suggests that anemones are not necessary for spawning in A. akallopisos. Light intensity was investigated as a cue for spawning. The reproductive behaviour of A. akallopisos was then studied under light intensities of 4.16 x 10¹⁵ quanta.sec⁻¹.cm⁻², 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻² and this intensity plus natural light. Spawning occurred mainly under 8.85 x 10¹⁵ quanta.sec⁻¹.cm⁻². Fish maintained under this light intensity exhibited significantly more of nest cleaning behaviour in terms of frequency and duration than fish maintained under low light intensity. A minimum light intensity of 8.85 x 10¹⁵ quanta. sec⁻¹.cm⁻² is recommended for conditioning of this species. This study can be of practical relevance to hatchery managers who can use the methods developed and record predictors for spawning in A. akallopisos and other Amphiprion species. In this way imminence of spawning may be estimated. Most importantly, the study also has academic merit as little work has been undertaken in this field. Although the observational method used in this study was adequate for the purposes of the investigation, future work of this nature should incorporate other methods of documenting gonadal development such as gonadal staging and GSI in order to obtain more conclusive results.
- Full Text:
- Date Issued: 1998
South African panorama: the novels of Daphne Rooke
- Authors: Coetzee, Paulette June
- Date: 1998
- Subjects: Rooke, Daphne, 1914- -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2222 , http://hdl.handle.net/10962/d1002265 , Rooke, Daphne, 1914- -- Criticism and interpretation
- Description: This thesis covers Daphne Rooke's eight published "South African" novels: A Grove of Fever Trees, Mittee, Ratoons, Wizards' Country, A Lover for Estelle, The Greyling, Diamond Jo, and Margaretha de la Porte. It supports the recent revival of critical interest in Rooke, and argues for the continuing relevance of her work in post-apartheid South Africa. This study also broadens the scope of recent Rooke research by including lesser known works like The Greyling and Margaretha de la Porte in its analysis. Recent criticism has focused on Rooke's unusual blend of romance and realism. The first three chapters concentrate more on "realism", emphasising the depth and extent of Rooke's engagement with serious social issues. The novels are examined in terms of their handling of the themes of class (chapter one), race (chapter two) and gender (chapter three). The concluding chapter shifts in focus to "romance" and examines the question of generic_identity -- touching on Rooke's gothic, magical realist and "popular" qualities -within a consideration of the particular "South African-ness" of her work.
- Full Text:
- Date Issued: 1998
- Authors: Coetzee, Paulette June
- Date: 1998
- Subjects: Rooke, Daphne, 1914- -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2222 , http://hdl.handle.net/10962/d1002265 , Rooke, Daphne, 1914- -- Criticism and interpretation
- Description: This thesis covers Daphne Rooke's eight published "South African" novels: A Grove of Fever Trees, Mittee, Ratoons, Wizards' Country, A Lover for Estelle, The Greyling, Diamond Jo, and Margaretha de la Porte. It supports the recent revival of critical interest in Rooke, and argues for the continuing relevance of her work in post-apartheid South Africa. This study also broadens the scope of recent Rooke research by including lesser known works like The Greyling and Margaretha de la Porte in its analysis. Recent criticism has focused on Rooke's unusual blend of romance and realism. The first three chapters concentrate more on "realism", emphasising the depth and extent of Rooke's engagement with serious social issues. The novels are examined in terms of their handling of the themes of class (chapter one), race (chapter two) and gender (chapter three). The concluding chapter shifts in focus to "romance" and examines the question of generic_identity -- touching on Rooke's gothic, magical realist and "popular" qualities -within a consideration of the particular "South African-ness" of her work.
- Full Text:
- Date Issued: 1998
Testing Guidano's model of psychopathology in eating-disordered individuals : a multiple case study
- Authors: Hajayiannis, Helen
- Date: 1998
- Subjects: Psychology, Pathological Eating disorders -- Case studies Guidano, V F Eating disorders -- Etiology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3192 , http://hdl.handle.net/10962/d1008557
- Description: This thesis sets out to critically examine Guidano's model of psychopathology in eating-disordered individuals . The literature review highlights the diverse etiological approaches that have been taken in understanding eating disorders. Guidano's model is presented as an alternative to traditional approaches . It is a developmental, unitary model of psychopathology, conceptualised within a systems/process-oriented approach to organised complexity. Within a qualitative framework, case study methodology is utilised to test the viability and limitations of Guidano's model. Four in-depth case histories are presented which offer appropriate material for the testing of the model. The data is analysed using the reading guide method and presented in terms of the four features of Guidano's model: (1) dysfunctional patterns of attachment; (2) sense of self; (3) major themes on systemic coherence; (4) common coping strategies. The findings of the research support Guidano's model of psychopathology in eating-disordered individuals. The findings are: (1) attachment styles are ambiguous, "intrusive, and enmeshed; participants experience a disappointment in the preferential attachment relationship; (2) that participants' sense of self is blurred and wavering; (3) the major theme on systemic coherence is the oscillation between seeking and avoiding intimacy; (4) common coping strategies are: the seeking of supportive intimacy with minimal self-exposure; withdrawal into the self; perfectionism; the development of an eating disorder; continuous thoughts about food, eating, and weight which prevents participants from becoming aware of the real issues confronting them. An evaluation of Guidano's model in terms of its specific contribution to knowledge and research on the role of father in child and adolescent psychopathology, as well as how father effects evidence in eating disorders, demonstrates the model's value as an explanatory tool and raises implications for future treatment, theory, and research practices of eating-disordered individuals.
- Full Text:
- Date Issued: 1998
- Authors: Hajayiannis, Helen
- Date: 1998
- Subjects: Psychology, Pathological Eating disorders -- Case studies Guidano, V F Eating disorders -- Etiology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3192 , http://hdl.handle.net/10962/d1008557
- Description: This thesis sets out to critically examine Guidano's model of psychopathology in eating-disordered individuals . The literature review highlights the diverse etiological approaches that have been taken in understanding eating disorders. Guidano's model is presented as an alternative to traditional approaches . It is a developmental, unitary model of psychopathology, conceptualised within a systems/process-oriented approach to organised complexity. Within a qualitative framework, case study methodology is utilised to test the viability and limitations of Guidano's model. Four in-depth case histories are presented which offer appropriate material for the testing of the model. The data is analysed using the reading guide method and presented in terms of the four features of Guidano's model: (1) dysfunctional patterns of attachment; (2) sense of self; (3) major themes on systemic coherence; (4) common coping strategies. The findings of the research support Guidano's model of psychopathology in eating-disordered individuals. The findings are: (1) attachment styles are ambiguous, "intrusive, and enmeshed; participants experience a disappointment in the preferential attachment relationship; (2) that participants' sense of self is blurred and wavering; (3) the major theme on systemic coherence is the oscillation between seeking and avoiding intimacy; (4) common coping strategies are: the seeking of supportive intimacy with minimal self-exposure; withdrawal into the self; perfectionism; the development of an eating disorder; continuous thoughts about food, eating, and weight which prevents participants from becoming aware of the real issues confronting them. An evaluation of Guidano's model in terms of its specific contribution to knowledge and research on the role of father in child and adolescent psychopathology, as well as how father effects evidence in eating disorders, demonstrates the model's value as an explanatory tool and raises implications for future treatment, theory, and research practices of eating-disordered individuals.
- Full Text:
- Date Issued: 1998
The Anglican Church's mission to the Muslims in Cape Town during the nineteenth and twentieth centuries : a study in the changes of missiological methods and attitudes
- Authors: Pratt, Derek Alfred
- Date: 1998
- Subjects: Missions to Muslims -- South Africa -- Cape Town Mission of the church Anglican Communion -- South Africa -- Cape Town Christianity and other religions -- Islam
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1236 , http://hdl.handle.net/10962/d1007592
- Description: When Bishop Robert Gray arrived at the Cape in 1848, he was concerned at the large percentage of the former slave population who had been attracted to the Muslim faith. He appointed Michael Angelo Camilleri (1848-1854) as a missionary to the Muslims of Cape Town. Camilleri's tenure was short and he was frequently used to fill other ecclesiastical posts. From 1854 until 1911 the responsibility of mission to the Muslims was given to priests whose parishes had large Muslims populations. In 1911 a fulltime missionary was once again appointed. Thomas Fothergill Lightfoot, arrived at the Cape in 1858 and served at St Paul's, Bree Street until his death in 1904. His was a ministry of love and caring. He was greatly respected for his work by all sections of the population. John Mühleissen Arnold worked in the parish of St Mary's, Woodstock. His aggressive missiological technique broke down much of the religious tolerance which had existed. His publication of a pamphlet supposedly written by a Muslim, raises doubts about his integrity as a missionary and his ethical stance as a Christian. In 1907 the Diocesan Mission Board took control of the Muslim mission and in 1911 appointed Stephen Garabedian as director. Under Garabedian the policy of the mission was aimed primarily at preventing Christian women 'lapsing' from Christianity and becoming Muslims through marriage. After his resignation in 1922, the work continued under numerous women workers who concentrated on Muslim women and children through sewing guilds and childrens' clubs. In 1960, George Swartz was appointed as director. Swartz was the first Coloured and South African-born priest to hold the post of director. Swartz served as director until he was appointed to Bonteheuwel as parish priest. He subsequently chaired the board until it ceased to meet in 1976. Throughout its one hundred twenty eight years of active existence, the Anglican mission to the Muslims failed to attract a large number of converts. Initially this could be attributed to the attraction the Muslims had to those seeking a strong community life. Later, outside influences from the Islamic world strengthened the faith of the Muslim community against any Christian conversion attempts. During the latter part of the twentieth century the mission viewed its tasks as preventing the conversion of Christians who wished to marry Muslims and informing and educating Christians on the Islamic faith. In the late 1960s, the Board encouraged dialogue rather than confrontation. It changed its name to the Board of Muslim Relationship. Apartheid was seen as the common enemy of both Christians and Muslims and they worked together against its evils. The need for a Mission Board was seen as redundant and from 1976 it ceased to be active.
- Full Text:
- Date Issued: 1998
- Authors: Pratt, Derek Alfred
- Date: 1998
- Subjects: Missions to Muslims -- South Africa -- Cape Town Mission of the church Anglican Communion -- South Africa -- Cape Town Christianity and other religions -- Islam
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1236 , http://hdl.handle.net/10962/d1007592
- Description: When Bishop Robert Gray arrived at the Cape in 1848, he was concerned at the large percentage of the former slave population who had been attracted to the Muslim faith. He appointed Michael Angelo Camilleri (1848-1854) as a missionary to the Muslims of Cape Town. Camilleri's tenure was short and he was frequently used to fill other ecclesiastical posts. From 1854 until 1911 the responsibility of mission to the Muslims was given to priests whose parishes had large Muslims populations. In 1911 a fulltime missionary was once again appointed. Thomas Fothergill Lightfoot, arrived at the Cape in 1858 and served at St Paul's, Bree Street until his death in 1904. His was a ministry of love and caring. He was greatly respected for his work by all sections of the population. John Mühleissen Arnold worked in the parish of St Mary's, Woodstock. His aggressive missiological technique broke down much of the religious tolerance which had existed. His publication of a pamphlet supposedly written by a Muslim, raises doubts about his integrity as a missionary and his ethical stance as a Christian. In 1907 the Diocesan Mission Board took control of the Muslim mission and in 1911 appointed Stephen Garabedian as director. Under Garabedian the policy of the mission was aimed primarily at preventing Christian women 'lapsing' from Christianity and becoming Muslims through marriage. After his resignation in 1922, the work continued under numerous women workers who concentrated on Muslim women and children through sewing guilds and childrens' clubs. In 1960, George Swartz was appointed as director. Swartz was the first Coloured and South African-born priest to hold the post of director. Swartz served as director until he was appointed to Bonteheuwel as parish priest. He subsequently chaired the board until it ceased to meet in 1976. Throughout its one hundred twenty eight years of active existence, the Anglican mission to the Muslims failed to attract a large number of converts. Initially this could be attributed to the attraction the Muslims had to those seeking a strong community life. Later, outside influences from the Islamic world strengthened the faith of the Muslim community against any Christian conversion attempts. During the latter part of the twentieth century the mission viewed its tasks as preventing the conversion of Christians who wished to marry Muslims and informing and educating Christians on the Islamic faith. In the late 1960s, the Board encouraged dialogue rather than confrontation. It changed its name to the Board of Muslim Relationship. Apartheid was seen as the common enemy of both Christians and Muslims and they worked together against its evils. The need for a Mission Board was seen as redundant and from 1976 it ceased to be active.
- Full Text:
- Date Issued: 1998
The Dance Factory, Newtown, Johannesburg a site of resistance
- Authors: Ginslov, Jeannette
- Date: 1998
- Subjects: Dance factory , Dance -- Political aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2139 , http://hdl.handle.net/10962/d1002371 , Dance factory , Dance -- Political aspects -- South Africa
- Description: This mini thesis proposes that the Dance Factory in Ne'Ntown, Johannesburg, is a site of resistance. Its source and motivation are the personal, artistic and socio-poIiticaI sites ofresistance to mainstream forms of dance with nationalistic tendencies and to dominant ideological hegemonies that enforced apartheid or nationalism. Therefore, these sites or resistance are examined prior to and after the democratisation of South African culture. An analysis of the dances choreographed in this period of transition and changing hegemonies reveal shifts of resistance. These are traced within the development of the Dance Factory. Chapter one explores the notion of resistance as a form of power and the notion of site, where the operations of power evoke resistance. Three sites of resistance within South African dance culture are identified and examined. These are the Dance Factory, the artistic site of dance and the site of the dancing body. The chapter reveals the development of these sites in a changed culture and notes a re-orientation of resistance within dance, namely Afro-fusion, and the subsequent development and emergence of 'alternative' sites of resistance. These reveal new expressionistic tendencies, body politics and the feminist strategies of 'new poetics' and 'ecriture feminine'. The codified mainstream forms of dance, subject to nationalistic strategies of dassicism and its inherent Iogocentricity are challenged and destabilised by the emergence of these altemative resistant forms of dance. Chapter two examines the artistic policies of the Nationalist Govemment, the African National Congress and the Dance Factory from 1983-1997. It notes the effects of the changes in the artistic policies on sites of resistance in dance, performed at the Dance Factory. The chapter desaibes the development of the Dance Factory, its policies of diversification as a strategy of resistance, its promotion of praxis, its resistance to nationalism and the ramifications thereof. It also explores the effects of a governmentalisation of culture and the role of the organic intellectual within the Dance Factory. An analysis of the alternative dance work 'Torso-Tongue" in chapter three furthers the argument that the Dance Factory maintains and encourages the changing sites of resistance in dance. This analysis demonstrates the resistant aspects of dance as discussed in chapter one and thereby confirms the aims and missions of the Dance Factory. The thesis examines the role of the Dance Factory as it develops, nurtures and responds to the shifts in resistance and changes in culture and dance. Most importantly the thesis exposes the resistance to and the effects of an imposition of a nationalistic ideology on dance. The resultant resistance to this form of domination is explored in dance within the site of the Dance Factory, thus supporting the premise that the Dance Factory is a site of resistance.
- Full Text:
- Date Issued: 1998
- Authors: Ginslov, Jeannette
- Date: 1998
- Subjects: Dance factory , Dance -- Political aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2139 , http://hdl.handle.net/10962/d1002371 , Dance factory , Dance -- Political aspects -- South Africa
- Description: This mini thesis proposes that the Dance Factory in Ne'Ntown, Johannesburg, is a site of resistance. Its source and motivation are the personal, artistic and socio-poIiticaI sites ofresistance to mainstream forms of dance with nationalistic tendencies and to dominant ideological hegemonies that enforced apartheid or nationalism. Therefore, these sites or resistance are examined prior to and after the democratisation of South African culture. An analysis of the dances choreographed in this period of transition and changing hegemonies reveal shifts of resistance. These are traced within the development of the Dance Factory. Chapter one explores the notion of resistance as a form of power and the notion of site, where the operations of power evoke resistance. Three sites of resistance within South African dance culture are identified and examined. These are the Dance Factory, the artistic site of dance and the site of the dancing body. The chapter reveals the development of these sites in a changed culture and notes a re-orientation of resistance within dance, namely Afro-fusion, and the subsequent development and emergence of 'alternative' sites of resistance. These reveal new expressionistic tendencies, body politics and the feminist strategies of 'new poetics' and 'ecriture feminine'. The codified mainstream forms of dance, subject to nationalistic strategies of dassicism and its inherent Iogocentricity are challenged and destabilised by the emergence of these altemative resistant forms of dance. Chapter two examines the artistic policies of the Nationalist Govemment, the African National Congress and the Dance Factory from 1983-1997. It notes the effects of the changes in the artistic policies on sites of resistance in dance, performed at the Dance Factory. The chapter desaibes the development of the Dance Factory, its policies of diversification as a strategy of resistance, its promotion of praxis, its resistance to nationalism and the ramifications thereof. It also explores the effects of a governmentalisation of culture and the role of the organic intellectual within the Dance Factory. An analysis of the alternative dance work 'Torso-Tongue" in chapter three furthers the argument that the Dance Factory maintains and encourages the changing sites of resistance in dance. This analysis demonstrates the resistant aspects of dance as discussed in chapter one and thereby confirms the aims and missions of the Dance Factory. The thesis examines the role of the Dance Factory as it develops, nurtures and responds to the shifts in resistance and changes in culture and dance. Most importantly the thesis exposes the resistance to and the effects of an imposition of a nationalistic ideology on dance. The resultant resistance to this form of domination is explored in dance within the site of the Dance Factory, thus supporting the premise that the Dance Factory is a site of resistance.
- Full Text:
- Date Issued: 1998
The development of academic literacy in the first-year psychology course at Rhodes University: an assessment of the tutorial programme
- Authors: Amos, Trevor Lawrence
- Date: 1998
- Subjects: Psychology -- Study and teaching (Higher) , Psychology -- Study and teaching (Higher) -- South Africa , Academic achievement -- South Africa , College student development programs -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2923 , http://hdl.handle.net/10962/d1002432 , Psychology -- Study and teaching (Higher) , Psychology -- Study and teaching (Higher) -- South Africa , Academic achievement -- South Africa , College student development programs -- South Africa
- Description: This research is concerned with the cognitive development of students in higher education. Specifically, it is recognised that the demands facing students are different to those previously encountered in secondary education. These demands include being able to master what Strohm Kitchener (1983) calls ill-structured problems and learning the groundrules of their academic disciplines. This is termed academic literacy. Current thought in academic development proposes that students need to be shown how to mobilise their cognitive processes to meet these demands. It is argued that this is best accomplished when such activities are integrated into the discipline itself as opposed to being an add-on process. Taking into account the social and dialectical nature of learning (Vygotsky, 1978), academic development and academic literacy are seen to best occur within the tutorial system. The purpose of this research was to evaluate the 1997 first-year Psychology tutorial programme at Rhodes University, Grahamstown to assess how academic literacy was being developed. A qualitative research approach was followed, guided by the ten stage evaluation model of education programmes (Jacobs, 1996) and an adapted version of the Context, Input, Process and Product approach to evaluation (Parlett and Hamilton cited in Calder, 1995, p.25). Using indepth interviews, data was gathered from eight first year students, seven staff members and one programme co-ordinator. Focus groups were used to gather data from nine tutors. Further data collection techniques included observation of tutor briefing sessions and tutorials as well as documentary research. Data was analysed using qualitative data analysis techniques (Coffey & Atkinson, 1996). The Psychology Department at Rhodes University aims to integrate the development of academic literacy into mainstream teaching at the first year level through its tutorial programme. The Department has conceptualised its understanding of academic development as the development of academic, vocational and professional literacy which is rather unique. Academic literacy is defined and conceptualised further in a list of pre-determined skills (reading, writing and general skills) to be developed incrementally. This conceptualisation of academic literacy tends to neglect to include the mobilisation of relevant cognitive processes explicitly and the implementation tends to remain implicit. A lack of tactical strategies to implement academic development is evidence of the difficulty in moving from the philosophical level of academic development to the practical level. The programme is perceived as disorganised and lacking in a co-ordinated or incremental development of the predetermined skills.
- Full Text:
- Date Issued: 1998
- Authors: Amos, Trevor Lawrence
- Date: 1998
- Subjects: Psychology -- Study and teaching (Higher) , Psychology -- Study and teaching (Higher) -- South Africa , Academic achievement -- South Africa , College student development programs -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2923 , http://hdl.handle.net/10962/d1002432 , Psychology -- Study and teaching (Higher) , Psychology -- Study and teaching (Higher) -- South Africa , Academic achievement -- South Africa , College student development programs -- South Africa
- Description: This research is concerned with the cognitive development of students in higher education. Specifically, it is recognised that the demands facing students are different to those previously encountered in secondary education. These demands include being able to master what Strohm Kitchener (1983) calls ill-structured problems and learning the groundrules of their academic disciplines. This is termed academic literacy. Current thought in academic development proposes that students need to be shown how to mobilise their cognitive processes to meet these demands. It is argued that this is best accomplished when such activities are integrated into the discipline itself as opposed to being an add-on process. Taking into account the social and dialectical nature of learning (Vygotsky, 1978), academic development and academic literacy are seen to best occur within the tutorial system. The purpose of this research was to evaluate the 1997 first-year Psychology tutorial programme at Rhodes University, Grahamstown to assess how academic literacy was being developed. A qualitative research approach was followed, guided by the ten stage evaluation model of education programmes (Jacobs, 1996) and an adapted version of the Context, Input, Process and Product approach to evaluation (Parlett and Hamilton cited in Calder, 1995, p.25). Using indepth interviews, data was gathered from eight first year students, seven staff members and one programme co-ordinator. Focus groups were used to gather data from nine tutors. Further data collection techniques included observation of tutor briefing sessions and tutorials as well as documentary research. Data was analysed using qualitative data analysis techniques (Coffey & Atkinson, 1996). The Psychology Department at Rhodes University aims to integrate the development of academic literacy into mainstream teaching at the first year level through its tutorial programme. The Department has conceptualised its understanding of academic development as the development of academic, vocational and professional literacy which is rather unique. Academic literacy is defined and conceptualised further in a list of pre-determined skills (reading, writing and general skills) to be developed incrementally. This conceptualisation of academic literacy tends to neglect to include the mobilisation of relevant cognitive processes explicitly and the implementation tends to remain implicit. A lack of tactical strategies to implement academic development is evidence of the difficulty in moving from the philosophical level of academic development to the practical level. The programme is perceived as disorganised and lacking in a co-ordinated or incremental development of the predetermined skills.
- Full Text:
- Date Issued: 1998
The diet of the black-backed jackal (Canis mesomelas) and caracal (Felis caracal) in the Eastern Cape, South Africa
- Authors: Bussiahn, Frans Ernst Carl
- Date: 1998
- Subjects: Black-backed jackal -- South Africa -- Eastern Cape , Felis -- South Africa -- Eastern Cape , Jackals -- South Africa -- Eastern Cape , Jackals -- Food , Felis -- Food
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5807 , http://hdl.handle.net/10962/d1006489 , Black-backed jackal -- South Africa -- Eastern Cape , Felis -- South Africa -- Eastern Cape , Jackals -- South Africa -- Eastern Cape , Jackals -- Food , Felis -- Food
- Description: The black-backed jackal (Canis mesomelas) and the caracal (Felis caracal) are considered by most farmers in the Eastern Cape to be responsible for excessive livestock losses (sheep and goats) and are, as such, hunted extensively within the Province. Stomach content analyses of individuals killed during predator control operations indicate that caracal are opportunistic hunters of small to medium-sized mammals, preying predominantly on antelope within farmland. Black-backed jackal are opportunistic omnivores, preying predominantly on livestock and antelope in farmland, while invertebrates and antelope constitute the major food items within a game reserve. The diet of caracal was found to be largely influenced by the age of individual animals with old and young animals being the predominant killers of livestock, whereas black-backed jackal diet is influenced primarily by the social structure exhibited by the species, with male animals exhibiting a marked summer peak in livestock killing, due to the increased energetic demands of parental care associated with a long term pair bond. Two caracal (a sub-adult male and adult female), were radio-tracked within farmland for a total of twelve months, yielding the smallest recorded homerange sizes for the species to date (2.1km² and 1.3km² respectively). No livestock losses were recorded within these homeranges for the duration of the study. These data suggest a relatively high abundance of caracal within Lower Albany and further illustrate that individual animals are capable of preying solely on natural prey species over an extended period, when occurring within livestock farming areas. The analysis of local hunt club records and questionnaires revealed a higher incidence of local black-backed jackal (15.2 PD/Kill), than caracal (34.7 PD/Kill), with a marked seasonal peak in kills, for both species, occurring during summer months. The use of hound packs was found to be more effective in reducing the overall abundance of caracal than black-backed jackal, as this technique was seen to eliminate more adult female caracal than black-backed jackal, during the respective breeding season of each species. Local hunt club owners and farmers were more accurate in identifying problem black-backed jackal (74%), than caracal (59%). Recommendations are presented for minimizing stock losses through the application of selective control of specific problem animals, the use of various control measures and encouraging natural prey abundance.
- Full Text:
- Date Issued: 1998
- Authors: Bussiahn, Frans Ernst Carl
- Date: 1998
- Subjects: Black-backed jackal -- South Africa -- Eastern Cape , Felis -- South Africa -- Eastern Cape , Jackals -- South Africa -- Eastern Cape , Jackals -- Food , Felis -- Food
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5807 , http://hdl.handle.net/10962/d1006489 , Black-backed jackal -- South Africa -- Eastern Cape , Felis -- South Africa -- Eastern Cape , Jackals -- South Africa -- Eastern Cape , Jackals -- Food , Felis -- Food
- Description: The black-backed jackal (Canis mesomelas) and the caracal (Felis caracal) are considered by most farmers in the Eastern Cape to be responsible for excessive livestock losses (sheep and goats) and are, as such, hunted extensively within the Province. Stomach content analyses of individuals killed during predator control operations indicate that caracal are opportunistic hunters of small to medium-sized mammals, preying predominantly on antelope within farmland. Black-backed jackal are opportunistic omnivores, preying predominantly on livestock and antelope in farmland, while invertebrates and antelope constitute the major food items within a game reserve. The diet of caracal was found to be largely influenced by the age of individual animals with old and young animals being the predominant killers of livestock, whereas black-backed jackal diet is influenced primarily by the social structure exhibited by the species, with male animals exhibiting a marked summer peak in livestock killing, due to the increased energetic demands of parental care associated with a long term pair bond. Two caracal (a sub-adult male and adult female), were radio-tracked within farmland for a total of twelve months, yielding the smallest recorded homerange sizes for the species to date (2.1km² and 1.3km² respectively). No livestock losses were recorded within these homeranges for the duration of the study. These data suggest a relatively high abundance of caracal within Lower Albany and further illustrate that individual animals are capable of preying solely on natural prey species over an extended period, when occurring within livestock farming areas. The analysis of local hunt club records and questionnaires revealed a higher incidence of local black-backed jackal (15.2 PD/Kill), than caracal (34.7 PD/Kill), with a marked seasonal peak in kills, for both species, occurring during summer months. The use of hound packs was found to be more effective in reducing the overall abundance of caracal than black-backed jackal, as this technique was seen to eliminate more adult female caracal than black-backed jackal, during the respective breeding season of each species. Local hunt club owners and farmers were more accurate in identifying problem black-backed jackal (74%), than caracal (59%). Recommendations are presented for minimizing stock losses through the application of selective control of specific problem animals, the use of various control measures and encouraging natural prey abundance.
- Full Text:
- Date Issued: 1998
The effect of different parameters on the rupture properties of leather in a tensile test
- Authors: Makhothe, Kelebohile
- Date: 1998
- Subjects: Leather -- Testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5462 , http://hdl.handle.net/10962/d1005247 , Leather -- Testing
- Description: This thesis explores the effect of some parameters on the breaking strain, strength and the shape of the stress-strain curve of bovine leather as revealed by uniaxial tensile tests. The parameters explored are fatliquoring, moisture content, strain rate and cyclic stressing. A basic mechanical model of a simple two-dimensional weave is created and used to describe the effect of such a weave on the shape of the stress-strain curve. It is found that fatliquoring lubricates and opens up the fibre structure and thereby makes the weave more extensible. The increase in the extensibility depends on the direction in which samples are cut and therefore the manner in which the fibres are orientated. Patliquoring is observed to increase the degree to which fibres pull out at break. There are indications that the strength of fatliquored leather decreases with time of storage, while the extensibility increases. The effect of the strain rate on the breaking strain, the tensile strength and the shape of the stress-strain curve is not very clear. The stressing and releasing leather decreases the strength of leather when the fibres are orientated preferentially along the direction of the applied stresses, but has an insignificant effect in the transverse direction. It is concluded that the degree of lubrication in a weave and the orientation of the fibre bundles significantly influence the performance of leather in a test. Both moisture and fatliquoring lubricate the weave. In both the cases the degree of fibre adhesions in a weave is decreased. A well lubricated weave allows its constituent fibres to slide and align along the direction of the applied stresses, and this tends to occur before the fibres themselves areextended. Cyclic testing, at low strains, ruptures fibre adhesions and as a result induces permanent set and makes a hide softer. Most of the work done in breaking the fibre adhesion is done in the first cycle.
- Full Text:
- Date Issued: 1998
- Authors: Makhothe, Kelebohile
- Date: 1998
- Subjects: Leather -- Testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5462 , http://hdl.handle.net/10962/d1005247 , Leather -- Testing
- Description: This thesis explores the effect of some parameters on the breaking strain, strength and the shape of the stress-strain curve of bovine leather as revealed by uniaxial tensile tests. The parameters explored are fatliquoring, moisture content, strain rate and cyclic stressing. A basic mechanical model of a simple two-dimensional weave is created and used to describe the effect of such a weave on the shape of the stress-strain curve. It is found that fatliquoring lubricates and opens up the fibre structure and thereby makes the weave more extensible. The increase in the extensibility depends on the direction in which samples are cut and therefore the manner in which the fibres are orientated. Patliquoring is observed to increase the degree to which fibres pull out at break. There are indications that the strength of fatliquored leather decreases with time of storage, while the extensibility increases. The effect of the strain rate on the breaking strain, the tensile strength and the shape of the stress-strain curve is not very clear. The stressing and releasing leather decreases the strength of leather when the fibres are orientated preferentially along the direction of the applied stresses, but has an insignificant effect in the transverse direction. It is concluded that the degree of lubrication in a weave and the orientation of the fibre bundles significantly influence the performance of leather in a test. Both moisture and fatliquoring lubricate the weave. In both the cases the degree of fibre adhesions in a weave is decreased. A well lubricated weave allows its constituent fibres to slide and align along the direction of the applied stresses, and this tends to occur before the fibres themselves areextended. Cyclic testing, at low strains, ruptures fibre adhesions and as a result induces permanent set and makes a hide softer. Most of the work done in breaking the fibre adhesion is done in the first cycle.
- Full Text:
- Date Issued: 1998
The effect of environmental factors and hormone treatments on ovulation rate and spawning success in cardinal tetras, Paracheirodon axelrodi (Pisces: Characidae)
- Authors: Burton, Simon Mark
- Date: 1998
- Subjects: Characidae , Characidae -- Breeding , Tropical fish -- Breeding , Fishes -- Induced spawning , Characidae -- Spawning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5273 , http://hdl.handle.net/10962/d1005117 , Characidae , Characidae -- Breeding , Tropical fish -- Breeding , Fishes -- Induced spawning , Characidae -- Spawning
- Description: Cardinal tetras, Paracheirodon axelrodi (Pisces: Characidae), are among the most popular tropical ornamental fish in the world. Millions of cardinal tetras are removed from their natural habitat, the upper tributaries of the Rio Negro in Brazil, each year and exported to North America and Europe where they are abundantly available at low cost. This, combined with the fact that they do not spawn freely in captivity has excluded any incentive to culture this fish on a commercial scale in these areas. However, the demand for cardinal tetras in South Africa is high, but their availability is limited to sporadic imports of wild caught fish which has resulted in an increase in their relative value. Thus, there is an appreciable incentive to investigate methods for inducing this species to reproduce in captivity. Information on methods for inducing spawning would form an integral part of a potential production plan for the culture of this species in South Africa. This study consisted of a number of experiments designed to investigate factors related to the spawning of cardinal tetras in captivity. The first series of experiments investigated the effect of variables such as the water chemistry of the experimental system, the sex ratio of the fish, the effect of conditioning and the effect of different spawning media on spawning success. The second series of experiments tested the effects of various environmental stimuli or hormonal treatments on spawning in cardinal tetras. Environmental stimuli tested included a rise in temperature, a rise in water level and a fresh rain water flush. Hormonal treatments included feeding GnRHa enriched brine shrimps to the fish or the application of hormone injections (hypophysation). Neither environmental stimuli nor brine shrimp enrichment induced cardinals to spawn in a repeatable manner. The same was true for hypophysation, but in this case a low incedence of ovulation of injected females was observed. Oocytes from ovulated and non-ovulated females were examined under a microscope and from this it was determined that cardinal tetras are group synchronous spawners, containing two distinct cohorts of oocytes in the ovary. The effect of a number of environmental stimuli on ovulation rate in cardinal tetras were then tested but did not induce ovulation in any females. A series of three experiments was performed investigating the effect of conditioning the sexes together on ovulation rate and spawning success. Conditioning the sexes together had no effect on spawning success, but a significantly higher ovulation rate was observed in females that vvere conditioned together with males. Male cardinals did not follow this trend and lost condition when conditioned together with females. The next experiment tested if pheromones from red serpae tetras, Hyphessobrycon serpae, could be used to induce ovulation and spawning in cardinal tetras. This was found not to be the case. The final series of experiments tested the effect of Aquaspawn® enriched Artemia on ovulation rates in female cardinal tetras. Aquaspawn® is a water soluble preparation of GnRHa and dopamine. Aquaspawn® enriched Artemia were found to be effective for inducing female cardinal tetras to ovulate. However, the results from this method of enrichment were not entirely reliable and further research is warranted. Finally, a protocol for evaluating spawning in topical, freshwater egg-laying fish was proposed, based on the results from this study. The advantages and disadvantages of such a protocol were discussed.
- Full Text:
- Date Issued: 1998
- Authors: Burton, Simon Mark
- Date: 1998
- Subjects: Characidae , Characidae -- Breeding , Tropical fish -- Breeding , Fishes -- Induced spawning , Characidae -- Spawning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5273 , http://hdl.handle.net/10962/d1005117 , Characidae , Characidae -- Breeding , Tropical fish -- Breeding , Fishes -- Induced spawning , Characidae -- Spawning
- Description: Cardinal tetras, Paracheirodon axelrodi (Pisces: Characidae), are among the most popular tropical ornamental fish in the world. Millions of cardinal tetras are removed from their natural habitat, the upper tributaries of the Rio Negro in Brazil, each year and exported to North America and Europe where they are abundantly available at low cost. This, combined with the fact that they do not spawn freely in captivity has excluded any incentive to culture this fish on a commercial scale in these areas. However, the demand for cardinal tetras in South Africa is high, but their availability is limited to sporadic imports of wild caught fish which has resulted in an increase in their relative value. Thus, there is an appreciable incentive to investigate methods for inducing this species to reproduce in captivity. Information on methods for inducing spawning would form an integral part of a potential production plan for the culture of this species in South Africa. This study consisted of a number of experiments designed to investigate factors related to the spawning of cardinal tetras in captivity. The first series of experiments investigated the effect of variables such as the water chemistry of the experimental system, the sex ratio of the fish, the effect of conditioning and the effect of different spawning media on spawning success. The second series of experiments tested the effects of various environmental stimuli or hormonal treatments on spawning in cardinal tetras. Environmental stimuli tested included a rise in temperature, a rise in water level and a fresh rain water flush. Hormonal treatments included feeding GnRHa enriched brine shrimps to the fish or the application of hormone injections (hypophysation). Neither environmental stimuli nor brine shrimp enrichment induced cardinals to spawn in a repeatable manner. The same was true for hypophysation, but in this case a low incedence of ovulation of injected females was observed. Oocytes from ovulated and non-ovulated females were examined under a microscope and from this it was determined that cardinal tetras are group synchronous spawners, containing two distinct cohorts of oocytes in the ovary. The effect of a number of environmental stimuli on ovulation rate in cardinal tetras were then tested but did not induce ovulation in any females. A series of three experiments was performed investigating the effect of conditioning the sexes together on ovulation rate and spawning success. Conditioning the sexes together had no effect on spawning success, but a significantly higher ovulation rate was observed in females that vvere conditioned together with males. Male cardinals did not follow this trend and lost condition when conditioned together with females. The next experiment tested if pheromones from red serpae tetras, Hyphessobrycon serpae, could be used to induce ovulation and spawning in cardinal tetras. This was found not to be the case. The final series of experiments tested the effect of Aquaspawn® enriched Artemia on ovulation rates in female cardinal tetras. Aquaspawn® is a water soluble preparation of GnRHa and dopamine. Aquaspawn® enriched Artemia were found to be effective for inducing female cardinal tetras to ovulate. However, the results from this method of enrichment were not entirely reliable and further research is warranted. Finally, a protocol for evaluating spawning in topical, freshwater egg-laying fish was proposed, based on the results from this study. The advantages and disadvantages of such a protocol were discussed.
- Full Text:
- Date Issued: 1998
The effects of night work and task diversification on efficiency of performance
- Authors: Munton, Lynne Kerry
- Date: 1998
- Subjects: Night work -- Evaluation , Shift systems , Performance
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5175 , http://hdl.handle.net/10962/d1018253
- Description: This study investigated the effects of night work on performance efficiency. Night work is generally acknowledged to impair performance, yet much research has contradicted this assertion. The feasibility of including brief periods of physical activity to stimulate arousal within mentally demanding work shifts was also evaluated. Thirty six postgraduate volunteers were assigned to either the cognitive tasks (CT) or cognitive and motor tasks (CMT) group. All subjects performed three psycho-motor tests, using the Vienna Test System, at midday and midnight. The CMT group performed a short cycling activity before each test. Heart rate responses served as physiological measures, the Perceived Strain Scale was used to quantify individual perceptions of strain and performance efficiency was assessed in terms of speed and accuracy. Although several trends were apparent, no significant differences (p < 0.05) were revealed with respect to the three performance variables between the midday and midnight test sessions, or between the CT and CMT subjects, other than the higher heart rates recorded in the CMT group. In summary, neither time of day nor physical activity were found to affect performance within the controlled environment of this study.
- Full Text:
- Date Issued: 1998
- Authors: Munton, Lynne Kerry
- Date: 1998
- Subjects: Night work -- Evaluation , Shift systems , Performance
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5175 , http://hdl.handle.net/10962/d1018253
- Description: This study investigated the effects of night work on performance efficiency. Night work is generally acknowledged to impair performance, yet much research has contradicted this assertion. The feasibility of including brief periods of physical activity to stimulate arousal within mentally demanding work shifts was also evaluated. Thirty six postgraduate volunteers were assigned to either the cognitive tasks (CT) or cognitive and motor tasks (CMT) group. All subjects performed three psycho-motor tests, using the Vienna Test System, at midday and midnight. The CMT group performed a short cycling activity before each test. Heart rate responses served as physiological measures, the Perceived Strain Scale was used to quantify individual perceptions of strain and performance efficiency was assessed in terms of speed and accuracy. Although several trends were apparent, no significant differences (p < 0.05) were revealed with respect to the three performance variables between the midday and midnight test sessions, or between the CT and CMT subjects, other than the higher heart rates recorded in the CMT group. In summary, neither time of day nor physical activity were found to affect performance within the controlled environment of this study.
- Full Text:
- Date Issued: 1998
The growth, development and impact of the Grahamstown Festival of the Arts with special reference to music
- Authors: Silva, Jane Susan
- Date: 1998
- Subjects: Standard Bank National Arts Festival -- Grahamstown , Standard Bank National Arts Festival -- Influence , Grahamstown (South Africa) -- Art and music , Music -- South Africa -- Eastern Cape -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2656 , http://hdl.handle.net/10962/d1002322 , Standard Bank National Arts Festival -- Grahamstown , Standard Bank National Arts Festival -- Influence , Grahamstown (South Africa) -- Art and music , Music -- South Africa -- Eastern Cape -- Grahamstown
- Description: The Grahamstown Festival has become a huge and complex annual celebration of the arts, transforming the small Eastern Cape city for ten days every year. However this event had very modest beginnings, as did music and festivals in the city of Grahamstown. From its early days Grahamstown showed strong signs of becoming an important cultural centre, presenting numerous musical concerts from 1812, the festival tradition in the city beginning in 1887. The modern arts festival, initiated in 1971, had a chequered history during the early and mid 1970's, weathering economic recession, petrol restrictions and a repressive and restrictive political atmosphere. However by 1979 the event had become established and popular enough to ensure continued success during the 1980's. The period 1980-89 was one of great growth and development for the festival regarding attendance, and the number and nature of productions presented. Music had always been an integral part of the festival, and for the first time its role in this artistic celebration is being examined. The impact of such an event is varied and far-reaching, and thus difficult to assess, but the thesis ends with an attempt to gauge the Festival's impact.
- Full Text:
- Date Issued: 1998
- Authors: Silva, Jane Susan
- Date: 1998
- Subjects: Standard Bank National Arts Festival -- Grahamstown , Standard Bank National Arts Festival -- Influence , Grahamstown (South Africa) -- Art and music , Music -- South Africa -- Eastern Cape -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2656 , http://hdl.handle.net/10962/d1002322 , Standard Bank National Arts Festival -- Grahamstown , Standard Bank National Arts Festival -- Influence , Grahamstown (South Africa) -- Art and music , Music -- South Africa -- Eastern Cape -- Grahamstown
- Description: The Grahamstown Festival has become a huge and complex annual celebration of the arts, transforming the small Eastern Cape city for ten days every year. However this event had very modest beginnings, as did music and festivals in the city of Grahamstown. From its early days Grahamstown showed strong signs of becoming an important cultural centre, presenting numerous musical concerts from 1812, the festival tradition in the city beginning in 1887. The modern arts festival, initiated in 1971, had a chequered history during the early and mid 1970's, weathering economic recession, petrol restrictions and a repressive and restrictive political atmosphere. However by 1979 the event had become established and popular enough to ensure continued success during the 1980's. The period 1980-89 was one of great growth and development for the festival regarding attendance, and the number and nature of productions presented. Music had always been an integral part of the festival, and for the first time its role in this artistic celebration is being examined. The impact of such an event is varied and far-reaching, and thus difficult to assess, but the thesis ends with an attempt to gauge the Festival's impact.
- Full Text:
- Date Issued: 1998