“As soon as the four sides are all equal, then the angles must be 90° each”: children's misconceptions in geometry
- Atebe, Humphrey U, Schäfer, Marc
- Authors: Atebe, Humphrey U , Schäfer, Marc
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140983 , vital:37934 , DOI: 10.1080/10288457.2008.10740634
- Description: This study describes Nigerian and South African students' conceptual understanding in high school geometry based on the van Hiele model of geometric thinking levels. The study further highlights students' misconceptions in school geometry. Concepts of triangles and quadrilaterals were investigated among 36 mathematics learners drawn from grades 10 through 12 who participated in this study. The tasks included identifying and naming shapes, sorting of shapes, stating the properties of shapes, defining of shapes and establishing class inclusions of shapes. The results indicated that many Nigerian and South African high school learners in Grade 10, 11 and 12 hold a number of misconceptions about geometric concepts of triangles and quadrilaterals.
- Full Text:
- Date Issued: 2013
- Authors: Atebe, Humphrey U , Schäfer, Marc
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140983 , vital:37934 , DOI: 10.1080/10288457.2008.10740634
- Description: This study describes Nigerian and South African students' conceptual understanding in high school geometry based on the van Hiele model of geometric thinking levels. The study further highlights students' misconceptions in school geometry. Concepts of triangles and quadrilaterals were investigated among 36 mathematics learners drawn from grades 10 through 12 who participated in this study. The tasks included identifying and naming shapes, sorting of shapes, stating the properties of shapes, defining of shapes and establishing class inclusions of shapes. The results indicated that many Nigerian and South African high school learners in Grade 10, 11 and 12 hold a number of misconceptions about geometric concepts of triangles and quadrilaterals.
- Full Text:
- Date Issued: 2013
‘Who? what?’: an uninducted view of towards a new psychology of women from post-Apartheid South Africa
- Authors: Macleod, Catriona I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6251 , http://hdl.handle.net/10962/d1007869 , http://journals.sagepub.com/doi/abs/10.1177/0959353508092088
- Description: From the text: Towards a New Psychology of Women (TPNW) promises a new psychology of “women”. On the cover of the second edition, the Toronto Globe and Mail is cited as acclaiming the book as “nothing short of revolutionary” as it “set out to recognize, re-define and understand the day-to-day experience of women”. But when we take a closer look at these “women” we discover that they are in fact “white”, (for the most part) middle-class women living in heterosexual relationships in a liberal democracy. This kind of exclusionary inclusion, in which the use of the generic term “woman” disguises the normative assumptions made about the race, class, sexual orientation and location of women, replicates the phallocentrism evidenced in the normalising masculinist terms “mankind” or “Man”. By now, of course, these kinds of critiques of “white” Western feminism by African American writers (e.g. Collins, 1999) postcolonial feminists (e.g. Mohanty, 1991), African feminists (e.g. Ogundipe-Leslie, 1994; Mangena, 2003), and queer theorists (e.g. Jackson, 1999) are well known.
- Full Text:
- Date Issued: 2008
- Authors: Macleod, Catriona I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6251 , http://hdl.handle.net/10962/d1007869 , http://journals.sagepub.com/doi/abs/10.1177/0959353508092088
- Description: From the text: Towards a New Psychology of Women (TPNW) promises a new psychology of “women”. On the cover of the second edition, the Toronto Globe and Mail is cited as acclaiming the book as “nothing short of revolutionary” as it “set out to recognize, re-define and understand the day-to-day experience of women”. But when we take a closer look at these “women” we discover that they are in fact “white”, (for the most part) middle-class women living in heterosexual relationships in a liberal democracy. This kind of exclusionary inclusion, in which the use of the generic term “woman” disguises the normative assumptions made about the race, class, sexual orientation and location of women, replicates the phallocentrism evidenced in the normalising masculinist terms “mankind” or “Man”. By now, of course, these kinds of critiques of “white” Western feminism by African American writers (e.g. Collins, 1999) postcolonial feminists (e.g. Mohanty, 1991), African feminists (e.g. Ogundipe-Leslie, 1994; Mangena, 2003), and queer theorists (e.g. Jackson, 1999) are well known.
- Full Text:
- Date Issued: 2008
‘Boys will be boys’: traditional Xhosa male circumcision, HIV and sexual socialisation in contemporary South Africa
- Authors: Vincent, Louise
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141500 , vital:37980 , DOI: 10.1080/13691050701861447
- Description: Ritual male circumcision is among the most secretive and sacred of rites practiced by the Xhosa of South Africa. Recently, the alarming rate of death and injury among initiates has led to the spotlight of media attention and government regulation being focused on traditional circumcision. While many of the physical components of the ritual have been little altered by the centuries, its cultural and social meanings have not remained unchanged. This paper attempts to understand how some of these cultural and social meanings have shifted, particularly with respect to attitudes towards sex and the role that circumcision schools traditionally played in the sexual.
- Full Text:
- Date Issued: 2008
- Authors: Vincent, Louise
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141500 , vital:37980 , DOI: 10.1080/13691050701861447
- Description: Ritual male circumcision is among the most secretive and sacred of rites practiced by the Xhosa of South Africa. Recently, the alarming rate of death and injury among initiates has led to the spotlight of media attention and government regulation being focused on traditional circumcision. While many of the physical components of the ritual have been little altered by the centuries, its cultural and social meanings have not remained unchanged. This paper attempts to understand how some of these cultural and social meanings have shifted, particularly with respect to attitudes towards sex and the role that circumcision schools traditionally played in the sexual.
- Full Text:
- Date Issued: 2008
Written out, writing in : orature in the South African literary canon
- Authors: Seddon, Deborah Ann
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:2263 , http://hdl.handle.net/10962/d1004695
- Description: As described by Duncan Brown, South African orature represents "our truly original contribution to world literature" (Brown, Voicing the Text 1). This paper explores how orature might be successfully 'written into' the South African literary canon whilst promoting recognition of its existence as an oral form. My recent experiences of the difficulties, challenges, and benefits of teaching South African orature within the Rhodes University English department, have alerted me to the urgent need for the creation of a student- and teacher-friendly anthology which would collect, re-voice, and adequately contextualise a selection of the seminal works of South African oral poets from the colonial to the post-apartheid periods. Much of this poetry already exists in print-form but, despite an increasing recognition of oral poetry through a number of endeavours such the Poetry Africa Festival, the Lentswe Poetry Project on SABC 2, the Timbila Poetry Project and others, South African orature remains marginal in the country's literary canon. It is largely absent from the curriculum in the literature departments of its universities. The need to redress this situation is crucial, but the process of setting up and teaching an undergraduate course in South African oral poetry, while possible, is complicated. The works of our most important oral poets are scattered in a variety of books, libraries, and collections. The usual process of drawing up a booklist of set texts is undermined by the stark reality that many of the books are out of print. Fully giving voice to these texts is even harder to achieve - CD and video recordings of performances (if they exist at all) are not easily accessed or disseminated.
- Full Text:
- Date Issued: 2008
- Authors: Seddon, Deborah Ann
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:2263 , http://hdl.handle.net/10962/d1004695
- Description: As described by Duncan Brown, South African orature represents "our truly original contribution to world literature" (Brown, Voicing the Text 1). This paper explores how orature might be successfully 'written into' the South African literary canon whilst promoting recognition of its existence as an oral form. My recent experiences of the difficulties, challenges, and benefits of teaching South African orature within the Rhodes University English department, have alerted me to the urgent need for the creation of a student- and teacher-friendly anthology which would collect, re-voice, and adequately contextualise a selection of the seminal works of South African oral poets from the colonial to the post-apartheid periods. Much of this poetry already exists in print-form but, despite an increasing recognition of oral poetry through a number of endeavours such the Poetry Africa Festival, the Lentswe Poetry Project on SABC 2, the Timbila Poetry Project and others, South African orature remains marginal in the country's literary canon. It is largely absent from the curriculum in the literature departments of its universities. The need to redress this situation is crucial, but the process of setting up and teaching an undergraduate course in South African oral poetry, while possible, is complicated. The works of our most important oral poets are scattered in a variety of books, libraries, and collections. The usual process of drawing up a booklist of set texts is undermined by the stark reality that many of the books are out of print. Fully giving voice to these texts is even harder to achieve - CD and video recordings of performances (if they exist at all) are not easily accessed or disseminated.
- Full Text:
- Date Issued: 2008
Women’s rights get a dressing down: mini skirt attacks in South Africa
- Authors: Vincent, Louise
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141888 , vital:38013 , DOI: 10.18848/1447-9508/cgp/v06i06/42462
- Description: On Sunday the 17th of February 2008 25-year old Nwabisa Ngcukana was stripped, paraded naked while more than 100 onlookers jeered and laughed, doused in alcohol and sexually assaulted by taxi drivers and hawkers at the Noord Street taxi rank in Johannesburg1 (The Star 2008: 2). She was the fourth woman to be assaulted in this way at the rank on that evening. Three other women were stripped and sexually assaulted at the same taxi rank on the previous day. In each of these cases the fact that the women were wearing mini skirts was cited as the reason for the attack.
- Full Text:
- Date Issued: 2008
- Authors: Vincent, Louise
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141888 , vital:38013 , DOI: 10.18848/1447-9508/cgp/v06i06/42462
- Description: On Sunday the 17th of February 2008 25-year old Nwabisa Ngcukana was stripped, paraded naked while more than 100 onlookers jeered and laughed, doused in alcohol and sexually assaulted by taxi drivers and hawkers at the Noord Street taxi rank in Johannesburg1 (The Star 2008: 2). She was the fourth woman to be assaulted in this way at the rank on that evening. Three other women were stripped and sexually assaulted at the same taxi rank on the previous day. In each of these cases the fact that the women were wearing mini skirts was cited as the reason for the attack.
- Full Text:
- Date Issued: 2008
Women writers of the South Asian diaspora : towards a transnational feminist Aesthetic?
- Authors: Naidu, Samantha
- Date: 2008
- Language: English
- Type: Article , text
- Identifier: vital:26375 , http://hdl.handle.net/10962/54027 , https://orcid.org/0000-0001-9456-8657
- Description: Women writers of the South Asian diaspora have, in recent decades, found prominence in the international literary arena. These writers may be new immigrants to their diasporic homes, migrants who divide their lives between far-flung homes (for example, Anita Desai, who lives in India, the United Kingdom [UK] and Germany), or descended from nineteenth-century immigrants, as is the case of South African authors like Farida Karodia and Agnes Sam.
- Full Text: false
- Date Issued: 2008
- Authors: Naidu, Samantha
- Date: 2008
- Language: English
- Type: Article , text
- Identifier: vital:26375 , http://hdl.handle.net/10962/54027 , https://orcid.org/0000-0001-9456-8657
- Description: Women writers of the South Asian diaspora have, in recent decades, found prominence in the international literary arena. These writers may be new immigrants to their diasporic homes, migrants who divide their lives between far-flung homes (for example, Anita Desai, who lives in India, the United Kingdom [UK] and Germany), or descended from nineteenth-century immigrants, as is the case of South African authors like Farida Karodia and Agnes Sam.
- Full Text: false
- Date Issued: 2008
Within- and between-beach variation in intertidal macrofaunal communities inhabiting two Transkei sandy beaches
- Authors: Dreyer, Nicolaas Burger
- Date: 2008
- Subjects: Intertidal animals -- Ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10700 , http://hdl.handle.net/10948/1070 , Intertidal animals -- Ecology -- South Africa
- Description: Until recently most sandy beach studies have made use of snapshot samples but the validity of this approach has been widely questioned. In this study we attempt to resolve this issue by repeatedly sampling two beaches using a stratified random design. Three sampling sessions took place, each approximately six months apart. The three sites on the first beach were selected according to the type of beach (reflective, intermediate and dissipative) with each morphological type duplicated on the second beach. Many of the physical variables measured had significant differences between the sampling sessions but only a few were significantly different between the Sites. Very few of the individual physical variables had significant relationships with the sandy beach macrofaunal abundance and density. However, composite indices had a greater number of significant relationships with the macrofaunal abundance and density. Also very few significant relationships were seen between the species richness and the physical variables of the beaches studied. Effluent line crossing frequency was the only physical variable that could predict species richness but it was considered a weak predictor. Changes in the zonation patterns within and between beaches were also investigated. The highest concentration of taxa and individuals was found near the low-water mark with a gradual reduction of both towards the high-water mark. Some of the sandy beach community variables (abundance, density and species richness) showed significant difference between the sampling sessions but no significant differences were seen between the two beaches. The presence of three zones was noted using MDS plots and Cluster diagrams. However, using a SIMPER analyses, four zones with the possibility of a fifth was noted.
- Full Text:
- Date Issued: 2008
- Authors: Dreyer, Nicolaas Burger
- Date: 2008
- Subjects: Intertidal animals -- Ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10700 , http://hdl.handle.net/10948/1070 , Intertidal animals -- Ecology -- South Africa
- Description: Until recently most sandy beach studies have made use of snapshot samples but the validity of this approach has been widely questioned. In this study we attempt to resolve this issue by repeatedly sampling two beaches using a stratified random design. Three sampling sessions took place, each approximately six months apart. The three sites on the first beach were selected according to the type of beach (reflective, intermediate and dissipative) with each morphological type duplicated on the second beach. Many of the physical variables measured had significant differences between the sampling sessions but only a few were significantly different between the Sites. Very few of the individual physical variables had significant relationships with the sandy beach macrofaunal abundance and density. However, composite indices had a greater number of significant relationships with the macrofaunal abundance and density. Also very few significant relationships were seen between the species richness and the physical variables of the beaches studied. Effluent line crossing frequency was the only physical variable that could predict species richness but it was considered a weak predictor. Changes in the zonation patterns within and between beaches were also investigated. The highest concentration of taxa and individuals was found near the low-water mark with a gradual reduction of both towards the high-water mark. Some of the sandy beach community variables (abundance, density and species richness) showed significant difference between the sampling sessions but no significant differences were seen between the two beaches. The presence of three zones was noted using MDS plots and Cluster diagrams. However, using a SIMPER analyses, four zones with the possibility of a fifth was noted.
- Full Text:
- Date Issued: 2008
WISC-IV performance of South African grade 7 English and Xhosa speaking children with advantaged versus disadvantaged education
- Authors: Van Tonder, Phia
- Date: 2008
- Subjects: Wechsler Intelligence Scale for Children Intelligence tests -- South Africa Educational tests and measurements -- South Africa Psychological tests -- Cross-cultural studies Educational psychology -- South Africa Language and languages -- Ability testing Educational evaluation -- South Africa Education, Elementary -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3098 , http://hdl.handle.net/10962/d1003920
- Description: Research reveals that the level as well as the quality of education plays a role in the determination of an individual's intellectual capacity. Substantial differences in quality of education for black and white individuals were experienced in South Africa due to Apartheid. Compared to the traditionally white Private and Model C schools, Township/ DET schools had limited resources, as well as a separate syllabus and examination system, a situation that has not improved substantially since democratisation in 1994. Research on black South African adults with the WAIS-III has confirmed significant influences on IQ in association with exposure to either such advantaged (Private/Model C) schooling, or disadvantaged (Township/DET) schooling. However to date there has been no published research on the use of the Wechsler intelligence tests on a black South African child population similarly stratified for quality of education. Therefore, for the purposes of this study, the latest Wechsler Intelligence Scale for Children (WISC-IV) was administered to a sample of 36 Grade 7 learners between the ages of 12-13 (mean 13.01 years), stratified for quality of education to form three comparative groups. Data analyses revealed significant differences on the WISC-IV Factor Indices and Full Scale IQ with the English speaking Private/Model C school group performing the best, followed by the Xhosa speaking Private/ Model C school group, and the Xhosa speaking Township/ DET school group performing the worst. This continuum of lowering is understood to occur abreast of a continuum of decreased exposure to relatively advantaged education. These normative indications are considered to have vital implications for the use of the WISC-IV in the South African cross-cultural situation where vastly differential educational opportunities continue to exist.
- Full Text:
- Date Issued: 2008
- Authors: Van Tonder, Phia
- Date: 2008
- Subjects: Wechsler Intelligence Scale for Children Intelligence tests -- South Africa Educational tests and measurements -- South Africa Psychological tests -- Cross-cultural studies Educational psychology -- South Africa Language and languages -- Ability testing Educational evaluation -- South Africa Education, Elementary -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3098 , http://hdl.handle.net/10962/d1003920
- Description: Research reveals that the level as well as the quality of education plays a role in the determination of an individual's intellectual capacity. Substantial differences in quality of education for black and white individuals were experienced in South Africa due to Apartheid. Compared to the traditionally white Private and Model C schools, Township/ DET schools had limited resources, as well as a separate syllabus and examination system, a situation that has not improved substantially since democratisation in 1994. Research on black South African adults with the WAIS-III has confirmed significant influences on IQ in association with exposure to either such advantaged (Private/Model C) schooling, or disadvantaged (Township/DET) schooling. However to date there has been no published research on the use of the Wechsler intelligence tests on a black South African child population similarly stratified for quality of education. Therefore, for the purposes of this study, the latest Wechsler Intelligence Scale for Children (WISC-IV) was administered to a sample of 36 Grade 7 learners between the ages of 12-13 (mean 13.01 years), stratified for quality of education to form three comparative groups. Data analyses revealed significant differences on the WISC-IV Factor Indices and Full Scale IQ with the English speaking Private/Model C school group performing the best, followed by the Xhosa speaking Private/ Model C school group, and the Xhosa speaking Township/ DET school group performing the worst. This continuum of lowering is understood to occur abreast of a continuum of decreased exposure to relatively advantaged education. These normative indications are considered to have vital implications for the use of the WISC-IV in the South African cross-cultural situation where vastly differential educational opportunities continue to exist.
- Full Text:
- Date Issued: 2008
Winds of change in teachers’ classroom assessment practice: a self-critical reflection on the teaching and learning of visual literacy in a rural Eastern Cape High School
- Authors: Mbelani, Madeyandile
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7021 , http://hdl.handle.net/10962/d1007201
- Description: The year 2006 saw the implementation of a new curriculum for teaching English First Additional Language (FAL) in grades 10-12 in South African high schools. The curriculum includes the teaching and assessment of visual literacy – a challenge for teachers whose apartheid-era teacher education did not address visual literacy at all. The article is a self-critical reflection on my attempts to teach and assess a unit on visual literacy in a Grade 10 class in a rural high school in the Eastern Cape province of South Africa.
- Full Text:
- Date Issued: 2008
- Authors: Mbelani, Madeyandile
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7021 , http://hdl.handle.net/10962/d1007201
- Description: The year 2006 saw the implementation of a new curriculum for teaching English First Additional Language (FAL) in grades 10-12 in South African high schools. The curriculum includes the teaching and assessment of visual literacy – a challenge for teachers whose apartheid-era teacher education did not address visual literacy at all. The article is a self-critical reflection on my attempts to teach and assess a unit on visual literacy in a Grade 10 class in a rural high school in the Eastern Cape province of South Africa.
- Full Text:
- Date Issued: 2008
Willingness to pay for the control of water hyacinth in an urban environment of South Africa
- Authors: Law, Matthew Charles
- Date: 2008
- Subjects: Water hyacinth -- Control -- South Africa , Urban ecology (Sociology) -- South Africa , Biodiversity -- Economic aspects -- South Africa , Biodiversity conservation -- Economic aspects -- South Africa , Biological invasions -- Economic aspects -- South Africa , Biological invasions -- Environmental aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:996 , http://hdl.handle.net/10962/d1002731 , Water hyacinth -- Control -- South Africa , Urban ecology (Sociology) -- South Africa , Biodiversity -- Economic aspects -- South Africa , Biodiversity conservation -- Economic aspects -- South Africa , Biological invasions -- Economic aspects -- South Africa , Biological invasions -- Environmental aspects -- South Africa
- Description: Water hyacinth is recognised as one of the most problematic invasive aquatic plant species in Africa. For this reason considerable funds are spent each year on itscontrol. As a consequence of the amount of money being spent on problems such as the invasion of water hyacinth, and because of the recognition of the ongoing and accelerated efforts that are required in the future, recent research has focused on accurately quantifying the costs and benefits of control of invasive species to aid policy decisions.A comprehensive cost-benefit analysis would be able to identify if the funds are justified and are being spent effectively. This thesis provides an example of a cost-benefit analysis of funds spent on the control of water hyacinth in an urban environment in South Africa. In order to develop a comprehensive assessment of the total economic value of the control of water hyacinth to an urban population, the Nahoon River in East London was selected as the study site to calculate the benefits of control. In addition to valuing the direct services provided by the resources that are traded in the market (in this case water provision), a contingent valuation study was undertaken in Abbottsford and Dorchester Heights (two suburbs in East London banking the Nahoon River). These were done in order to assess any non-use value a sample of 132 households of the population has for the control of water hyacinth, and any use values that are not traded in the market, for example recreational value. When the benefits of control of water hyacinth were compared to the costs of one of the least cost effective methods of control (herbicidal control), the benefits outweighed the costs by a ratio of more than 4:1, and for the most cost effective method of control the ratio was almost 6:1. These results provide a justification for the funds that are devoted to the control of water hyacinth, providing an argument for the continued expenditure for its control, and for further research into more cost effective methods of control, such as biological control.
- Full Text:
- Date Issued: 2008
- Authors: Law, Matthew Charles
- Date: 2008
- Subjects: Water hyacinth -- Control -- South Africa , Urban ecology (Sociology) -- South Africa , Biodiversity -- Economic aspects -- South Africa , Biodiversity conservation -- Economic aspects -- South Africa , Biological invasions -- Economic aspects -- South Africa , Biological invasions -- Environmental aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:996 , http://hdl.handle.net/10962/d1002731 , Water hyacinth -- Control -- South Africa , Urban ecology (Sociology) -- South Africa , Biodiversity -- Economic aspects -- South Africa , Biodiversity conservation -- Economic aspects -- South Africa , Biological invasions -- Economic aspects -- South Africa , Biological invasions -- Environmental aspects -- South Africa
- Description: Water hyacinth is recognised as one of the most problematic invasive aquatic plant species in Africa. For this reason considerable funds are spent each year on itscontrol. As a consequence of the amount of money being spent on problems such as the invasion of water hyacinth, and because of the recognition of the ongoing and accelerated efforts that are required in the future, recent research has focused on accurately quantifying the costs and benefits of control of invasive species to aid policy decisions.A comprehensive cost-benefit analysis would be able to identify if the funds are justified and are being spent effectively. This thesis provides an example of a cost-benefit analysis of funds spent on the control of water hyacinth in an urban environment in South Africa. In order to develop a comprehensive assessment of the total economic value of the control of water hyacinth to an urban population, the Nahoon River in East London was selected as the study site to calculate the benefits of control. In addition to valuing the direct services provided by the resources that are traded in the market (in this case water provision), a contingent valuation study was undertaken in Abbottsford and Dorchester Heights (two suburbs in East London banking the Nahoon River). These were done in order to assess any non-use value a sample of 132 households of the population has for the control of water hyacinth, and any use values that are not traded in the market, for example recreational value. When the benefits of control of water hyacinth were compared to the costs of one of the least cost effective methods of control (herbicidal control), the benefits outweighed the costs by a ratio of more than 4:1, and for the most cost effective method of control the ratio was almost 6:1. These results provide a justification for the funds that are devoted to the control of water hyacinth, providing an argument for the continued expenditure for its control, and for further research into more cost effective methods of control, such as biological control.
- Full Text:
- Date Issued: 2008
Widowhood and property inheritance in Zimbabwe: experiences of widows in Sikalenge ward, Binga District
- Authors: Dube, Misheck
- Date: 2008
- Subjects: Widows -- Legal status, laws, etc. -- Zimbabwe , Women -- Legal status, laws, etc. -- Zimbabwe , Inheritance and succession -- Zimbabwe
- Language: English
- Type: Thesis , Masters , M SW
- Identifier: vital:11755 , http://hdl.handle.net/10353/200 , Widows -- Legal status, laws, etc. -- Zimbabwe , Women -- Legal status, laws, etc. -- Zimbabwe , Inheritance and succession -- Zimbabwe
- Description: Zimbabwean widows need to inherit property when their husbands die. Property, be it material or financial in nature, is a source of sustenance and wealth. Depriving women of property inheritance rights has untold consequences. This study focuses on the property inheritance rights of widows in Zimbabwe in the Sikalenge Ward of Binga District. The aim of the study is to understand how property grabbing affects widows and to find possible solutions and intervention strategies social workers may use. The literature reviewed in the study was drawn from both the legal field and social work to create a link between the fields. The study was shaped by radical feminism for conceptualising property grabbing while the formulated intervention strategies utilised the empowerment model. The study is qualitative in nature using interviews to collect data from ten widows and five social service providers who constitute the total of fifteen participants in the study. Data was analysed qualitatively using interpretive approaches and presentation is textual rather than statistical. The main finding of the study is that widows are still being denied their inheritance rights despite the provision of such rights by the Intestate Succession Laws promulgated in November 1997 by the government of Zimbabwe. Moreover, the widows are not aware of the inheritance laws of Zimbabwe and hence did not seek any professional intervention. The few who attempted the legal process for recourse were not successful. Even though it was minimally attempted, the study established that the main form of failed intervention tried by the women was legal in nature and suggests and emphasises an eminent need for Social Work intervention to supplement legal intervention.
- Full Text:
- Date Issued: 2008
- Authors: Dube, Misheck
- Date: 2008
- Subjects: Widows -- Legal status, laws, etc. -- Zimbabwe , Women -- Legal status, laws, etc. -- Zimbabwe , Inheritance and succession -- Zimbabwe
- Language: English
- Type: Thesis , Masters , M SW
- Identifier: vital:11755 , http://hdl.handle.net/10353/200 , Widows -- Legal status, laws, etc. -- Zimbabwe , Women -- Legal status, laws, etc. -- Zimbabwe , Inheritance and succession -- Zimbabwe
- Description: Zimbabwean widows need to inherit property when their husbands die. Property, be it material or financial in nature, is a source of sustenance and wealth. Depriving women of property inheritance rights has untold consequences. This study focuses on the property inheritance rights of widows in Zimbabwe in the Sikalenge Ward of Binga District. The aim of the study is to understand how property grabbing affects widows and to find possible solutions and intervention strategies social workers may use. The literature reviewed in the study was drawn from both the legal field and social work to create a link between the fields. The study was shaped by radical feminism for conceptualising property grabbing while the formulated intervention strategies utilised the empowerment model. The study is qualitative in nature using interviews to collect data from ten widows and five social service providers who constitute the total of fifteen participants in the study. Data was analysed qualitatively using interpretive approaches and presentation is textual rather than statistical. The main finding of the study is that widows are still being denied their inheritance rights despite the provision of such rights by the Intestate Succession Laws promulgated in November 1997 by the government of Zimbabwe. Moreover, the widows are not aware of the inheritance laws of Zimbabwe and hence did not seek any professional intervention. The few who attempted the legal process for recourse were not successful. Even though it was minimally attempted, the study established that the main form of failed intervention tried by the women was legal in nature and suggests and emphasises an eminent need for Social Work intervention to supplement legal intervention.
- Full Text:
- Date Issued: 2008
Whole body vibration training effects on asthma specific pulmonary variables
- Authors: Mansell, Ingrid Joan
- Date: 2008
- Subjects: Vibration -- Physiological effect , Asthma -- Exercise therapy , Asthma -- Treatment
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10112 , http://hdl.handle.net/10948/d1020953
- Description: The aim of the study was to determine and document evidence of the comparative effect of a 12- week whole body vibration training programme, exercise training programme and sedentary control group on the anthropometric profile, aerobic capacity, lung volumes and hence, the pulmonary capacity in people with asthma. The study used a descriptive, exploratory, quasi-experimental research approach employing randomised pairing to classify participants into either the whole body vibration therapy or exercise training group. Accidental and snowball sampling was used to identify and obtain a base of volunteers. A three-group pre-test/post-test design was employed to gain insight into statistical differences that might be apparent between the whole body vibration therapy group, the exercise group and the control group, and which could potentially be attributed to participation in the whole body vibration exercise programme. Randomised pairing for participant selection was selected because of the potential effects varying pulmonary variables might have had on the reliability of the study. A Physical Activity Selection Criteria Questionnaire was completed by participants to ascertain baseline physical activity readiness and as a means of determining selection criteria for their allocation to the whole body vibration training group, the experimental exercise group or the true control group. The pre-test/post-test assessment made use of a combination evaluation that incorporated an anthropometric profile assessment of height, weight, biceps, triceps, subscapular and suprailliac skinfolds, waist and hip circumference and posture, an aerobic capacity evaluation that incorporated aspects of both the YMCA and Astrand and Rhyming Physical Work Capacity (PWC) evaluation on a cycle ergometer and, lastly, a pulmonary variable assessment that made use of both the Datospir Peak-10 peak flow meter and the Spirovit SP-100AT spirometry unit integrated into the Cardiovit AT-6 model for all spirometry measurements. Participants were required to complete either the whole-body vibration or the exercise training programme a minimum of twice a week and a maximum of four times over the same period. The duration of the intervention programmes was approximately 30 minutes and consisted of three sections including a warm-up comprising flexibility exercises, whole body strength training exercises, and a cool-down which, in turn, consisted of massage exercises or replicated flexibility exercises. The main difference between the whole body vibration and exercise training group thus lay in the exclusion of the use of vibration for those participants assigned to the exercise training programme. Analysis of data was performed using descriptive and inferential statistics with the help of a qualified statistician. The identified variables were tested at a 95 percent level of probability (p<0.05) as recommended by Thomas and Nelson (1996:117). Descriptive data, in the form of a statistical mean, standard deviation, minimum, median and maximum values, obtained during this study were reported in the form of a t-score for selected anthropometric and pulmonary variables. The 12-week intervention programme, on analysis of the results, produced statistically insignificant improvements in the variables of anthropometric profile, aerobic capacity and lung volumes identified as determinants of, and factors influencing, the cardiorespiratory fitness level of participants with asthma and hence, the subsequent severity of this chronic condition. However, slight mean increases for the whole body vibration training group were evident for certain variables identified in this study. Based on the results, the inference could be made that whole body vibration therapy and exercise were both effective modes of training to improve the cardiorespiratory fitness level of people with asthma, but the results of the study did not show sufficient practical or statistical significance to verify the assumption that whole body vibration training was a method superior to conventional exercise training. Hence, the significance of whole body vibration training on the pulmonary variables of people with asthma could not be determined. The researcher recommends that future studies be undertaken to verify whether whole body vibration training incorporating larger participant groups could produce significant improvements in pulmonary variables in people with asthma.
- Full Text:
- Date Issued: 2008
- Authors: Mansell, Ingrid Joan
- Date: 2008
- Subjects: Vibration -- Physiological effect , Asthma -- Exercise therapy , Asthma -- Treatment
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10112 , http://hdl.handle.net/10948/d1020953
- Description: The aim of the study was to determine and document evidence of the comparative effect of a 12- week whole body vibration training programme, exercise training programme and sedentary control group on the anthropometric profile, aerobic capacity, lung volumes and hence, the pulmonary capacity in people with asthma. The study used a descriptive, exploratory, quasi-experimental research approach employing randomised pairing to classify participants into either the whole body vibration therapy or exercise training group. Accidental and snowball sampling was used to identify and obtain a base of volunteers. A three-group pre-test/post-test design was employed to gain insight into statistical differences that might be apparent between the whole body vibration therapy group, the exercise group and the control group, and which could potentially be attributed to participation in the whole body vibration exercise programme. Randomised pairing for participant selection was selected because of the potential effects varying pulmonary variables might have had on the reliability of the study. A Physical Activity Selection Criteria Questionnaire was completed by participants to ascertain baseline physical activity readiness and as a means of determining selection criteria for their allocation to the whole body vibration training group, the experimental exercise group or the true control group. The pre-test/post-test assessment made use of a combination evaluation that incorporated an anthropometric profile assessment of height, weight, biceps, triceps, subscapular and suprailliac skinfolds, waist and hip circumference and posture, an aerobic capacity evaluation that incorporated aspects of both the YMCA and Astrand and Rhyming Physical Work Capacity (PWC) evaluation on a cycle ergometer and, lastly, a pulmonary variable assessment that made use of both the Datospir Peak-10 peak flow meter and the Spirovit SP-100AT spirometry unit integrated into the Cardiovit AT-6 model for all spirometry measurements. Participants were required to complete either the whole-body vibration or the exercise training programme a minimum of twice a week and a maximum of four times over the same period. The duration of the intervention programmes was approximately 30 minutes and consisted of three sections including a warm-up comprising flexibility exercises, whole body strength training exercises, and a cool-down which, in turn, consisted of massage exercises or replicated flexibility exercises. The main difference between the whole body vibration and exercise training group thus lay in the exclusion of the use of vibration for those participants assigned to the exercise training programme. Analysis of data was performed using descriptive and inferential statistics with the help of a qualified statistician. The identified variables were tested at a 95 percent level of probability (p<0.05) as recommended by Thomas and Nelson (1996:117). Descriptive data, in the form of a statistical mean, standard deviation, minimum, median and maximum values, obtained during this study were reported in the form of a t-score for selected anthropometric and pulmonary variables. The 12-week intervention programme, on analysis of the results, produced statistically insignificant improvements in the variables of anthropometric profile, aerobic capacity and lung volumes identified as determinants of, and factors influencing, the cardiorespiratory fitness level of participants with asthma and hence, the subsequent severity of this chronic condition. However, slight mean increases for the whole body vibration training group were evident for certain variables identified in this study. Based on the results, the inference could be made that whole body vibration therapy and exercise were both effective modes of training to improve the cardiorespiratory fitness level of people with asthma, but the results of the study did not show sufficient practical or statistical significance to verify the assumption that whole body vibration training was a method superior to conventional exercise training. Hence, the significance of whole body vibration training on the pulmonary variables of people with asthma could not be determined. The researcher recommends that future studies be undertaken to verify whether whole body vibration training incorporating larger participant groups could produce significant improvements in pulmonary variables in people with asthma.
- Full Text:
- Date Issued: 2008
Whole body vibration training and physical fitness of persons with diabetes melitus type II
- Authors: Bekker, Lindy
- Date: 2008
- Subjects: Diabetes -- Exercise therapy , Vibration -- Physiological effect
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10096 , http://hdl.handle.net/10948/672 , Diabetes -- Exercise therapy , Vibration -- Physiological effect
- Description: The aim of this study was to determine the effect of whole body vibration training on selected health and fitness parameters, including: blood glucose levels, blood pressure, anthropometric profile, muscular flexibility, muscular strength, muscular endurance, and aerobic endurance of persons with diabetes mellitus type II. The study was conducted in a descriptive, explorative manner utilizing a quasiexperimental design with an equistatic approach, employing match-pair design to participant grouping. The experimental design was a non-randomized two-group pre- and post-test design, in which approximately 16 male and female participants, who were chosen through convenience and snowball sampling with diabetes mellitus type II, completed the study. Pre- and post-test analysis was performed at the Biokinetics and Sport Science Unit. The whole body vibration training (experimental) group, trained three times a week for a period of ten weeks, performing exercises on the vibration platform with progressive increments in the intensity, duration, and number of the exercises. The control group remained sedentary throughout the intervention period. The dependant variables were analyzed using descriptive statistics. ANOVA was done to determine pre- and post-test differences for both the experimental and control groups for all the variables. Post-Hoc analysis was done to determine and compare differences which may have existed between the experimental and control groups, with practical significance being determined by Cohen’s D analysis. The analysis of the results revealed significant improvements in systolic blood pressure, muscular strength, muscular endurance, and aerobic endurance.
- Full Text:
- Date Issued: 2008
- Authors: Bekker, Lindy
- Date: 2008
- Subjects: Diabetes -- Exercise therapy , Vibration -- Physiological effect
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10096 , http://hdl.handle.net/10948/672 , Diabetes -- Exercise therapy , Vibration -- Physiological effect
- Description: The aim of this study was to determine the effect of whole body vibration training on selected health and fitness parameters, including: blood glucose levels, blood pressure, anthropometric profile, muscular flexibility, muscular strength, muscular endurance, and aerobic endurance of persons with diabetes mellitus type II. The study was conducted in a descriptive, explorative manner utilizing a quasiexperimental design with an equistatic approach, employing match-pair design to participant grouping. The experimental design was a non-randomized two-group pre- and post-test design, in which approximately 16 male and female participants, who were chosen through convenience and snowball sampling with diabetes mellitus type II, completed the study. Pre- and post-test analysis was performed at the Biokinetics and Sport Science Unit. The whole body vibration training (experimental) group, trained three times a week for a period of ten weeks, performing exercises on the vibration platform with progressive increments in the intensity, duration, and number of the exercises. The control group remained sedentary throughout the intervention period. The dependant variables were analyzed using descriptive statistics. ANOVA was done to determine pre- and post-test differences for both the experimental and control groups for all the variables. Post-Hoc analysis was done to determine and compare differences which may have existed between the experimental and control groups, with practical significance being determined by Cohen’s D analysis. The analysis of the results revealed significant improvements in systolic blood pressure, muscular strength, muscular endurance, and aerobic endurance.
- Full Text:
- Date Issued: 2008
When commercial can also be community:
- Authors: du Toit, Peter , Rau, Asta
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159322 , vital:40287 , https://hdl.handle.net/10520/EJC140094
- Description: Questions of ownership, control and profit distribution are widely used to distinguish between commercial and community media ventures, but an over-reliance on such distinctions may eclipse other important considerations in a way that impacts negatively on media diversity.
- Full Text:
- Date Issued: 2008
- Authors: du Toit, Peter , Rau, Asta
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159322 , vital:40287 , https://hdl.handle.net/10520/EJC140094
- Description: Questions of ownership, control and profit distribution are widely used to distinguish between commercial and community media ventures, but an over-reliance on such distinctions may eclipse other important considerations in a way that impacts negatively on media diversity.
- Full Text:
- Date Issued: 2008
What future subordinates will value in their leaders
- Cox, A, Amos, Trevor L, Baxter, Jeremy
- Authors: Cox, A , Amos, Trevor L , Baxter, Jeremy
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270992 , vital:54499 , xlink:href="https://hdl.handle.net/10520/EJC51031"
- Description: Leaders should not randomly choose a leadership style. To be effective, leaders need to ensure that their leadership style is congruent with what subordinates value. The focus of this study is on what the future South African graduate workforce will value in a leader. The female and male respondents in this study emphasise similar leadership values, indicating that there is no distinct set of competencies that will be valued separately by males and females. The same was found for respondents of different cultures, namely African, Coloured, Indian, White and other. With respect to both gender and culture, the respondents emphasise a mixture of African and Western leadership values. This supports the idea that to be effective in South Africa, leaders need to understand the prevailing national cultural values before simply applying ''foreign'' leadership models and theories based upon cultural values found in the West. This research finds that irrespective of gender and culture in the South African workplace, to be effective, leaders need to be loyal and inspirational, have vision and integrity and must be open and honest with their subordinates. Leaders should avoid being autocratic, strict, religious, ritualistic and traditional. They should also avoid using consensus and perceived external control.
- Full Text:
- Date Issued: 2008
- Authors: Cox, A , Amos, Trevor L , Baxter, Jeremy
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270992 , vital:54499 , xlink:href="https://hdl.handle.net/10520/EJC51031"
- Description: Leaders should not randomly choose a leadership style. To be effective, leaders need to ensure that their leadership style is congruent with what subordinates value. The focus of this study is on what the future South African graduate workforce will value in a leader. The female and male respondents in this study emphasise similar leadership values, indicating that there is no distinct set of competencies that will be valued separately by males and females. The same was found for respondents of different cultures, namely African, Coloured, Indian, White and other. With respect to both gender and culture, the respondents emphasise a mixture of African and Western leadership values. This supports the idea that to be effective in South Africa, leaders need to understand the prevailing national cultural values before simply applying ''foreign'' leadership models and theories based upon cultural values found in the West. This research finds that irrespective of gender and culture in the South African workplace, to be effective, leaders need to be loyal and inspirational, have vision and integrity and must be open and honest with their subordinates. Leaders should avoid being autocratic, strict, religious, ritualistic and traditional. They should also avoid using consensus and perceived external control.
- Full Text:
- Date Issued: 2008
WET-Origins: controls on the distribution and dynamics of wetlands in South Africa
- Ellery, William F N, Grenfell, Michael C, Grenfell, Suzanne E, Kotze, Donovan C, McCarthy, Terence, Tooth, Stephen, Grundling, Piet-Louis, Beckedahl, Heinz, Le Maitre, David C, Ramsay, Lisa
- Authors: Ellery, William F N , Grenfell, Michael C , Grenfell, Suzanne E , Kotze, Donovan C , McCarthy, Terence , Tooth, Stephen , Grundling, Piet-Louis , Beckedahl, Heinz , Le Maitre, David C , Ramsay, Lisa
- Date: 2008
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/176598 , vital:40091 , ISBN 978-77005-633-6 , https://www.wrc.org.za/mdocs-posts/wetland-management-series-wet-origins-controls-on-the-distribution-and-dynamics-of-wetlands-in-south-africa/
- Description: The need for wetland rehabilitation in South Africa is compelling: loss and degradation of wetlands have been great and national policy and legislation provide clear direction and support for rehabilitation. However, rehabilitating wetlands is often complex because wetlands and their links with people are complex (e.g. through the ways that people use wetlands and the different benefits that people receive from the ecosystem services that wetlands supply).
- Full Text:
- Date Issued: 2008
- Authors: Ellery, William F N , Grenfell, Michael C , Grenfell, Suzanne E , Kotze, Donovan C , McCarthy, Terence , Tooth, Stephen , Grundling, Piet-Louis , Beckedahl, Heinz , Le Maitre, David C , Ramsay, Lisa
- Date: 2008
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/176598 , vital:40091 , ISBN 978-77005-633-6 , https://www.wrc.org.za/mdocs-posts/wetland-management-series-wet-origins-controls-on-the-distribution-and-dynamics-of-wetlands-in-south-africa/
- Description: The need for wetland rehabilitation in South Africa is compelling: loss and degradation of wetlands have been great and national policy and legislation provide clear direction and support for rehabilitation. However, rehabilitating wetlands is often complex because wetlands and their links with people are complex (e.g. through the ways that people use wetlands and the different benefits that people receive from the ecosystem services that wetlands supply).
- Full Text:
- Date Issued: 2008
Water, salt and nutrient budgets of the Swartkops and Sundays river estuaries using the loicz biogeochemical budgeting protocol
- Authors: Potgieter, Matthys Johannes
- Date: 2008
- Subjects: Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10705 , http://hdl.handle.net/10948/903 , Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Description: The Swartkops River and Sundays River Estuaries are different in terms of morphology and the level of human impact. Budget models of DIP and DIN were constructed for each estuary at different riverine flow rates, using the Land-Ocean Interactions in the Coastal Zone (LOICZ) protocol. Nutrient dynamics in the estuaries were investigated using nutrient data and the results of the models. The Swartkops River Estuary acted as a sink of DIP and DIN, while being net heterotrophic. The Sundays River Estuary acted as a source of DIP and DIN, while being net autotrophic. Both systems were net denitrifying. The Swartkops River Estuary shows greater anthropogenic impacts in terms of nutrient loads than the Sundays River Estuary. A shift in nutrient concentration trends and system properties occurred between conditions of low and high riverine flow rates. The Swartkops River and Sundays River Estuaries were shown to be ‘outwellers’ of DIN and DIP, while having an important influence on the ratio of DIN:DIP exported to the adjacent ocean. Comparisons with other estuaries suggested that riverine flow into estuaries in the Eastern Cape region may display natural DIN:DIP ratios which are lower than the global average for “pristine” systems. Such ratios would be decreased further by increased water extraction for human activities.
- Full Text:
- Date Issued: 2008
- Authors: Potgieter, Matthys Johannes
- Date: 2008
- Subjects: Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10705 , http://hdl.handle.net/10948/903 , Estuarine oceanography , Groundwater flow -- South Africa -- Swartkops River Estuary
- Description: The Swartkops River and Sundays River Estuaries are different in terms of morphology and the level of human impact. Budget models of DIP and DIN were constructed for each estuary at different riverine flow rates, using the Land-Ocean Interactions in the Coastal Zone (LOICZ) protocol. Nutrient dynamics in the estuaries were investigated using nutrient data and the results of the models. The Swartkops River Estuary acted as a sink of DIP and DIN, while being net heterotrophic. The Sundays River Estuary acted as a source of DIP and DIN, while being net autotrophic. Both systems were net denitrifying. The Swartkops River Estuary shows greater anthropogenic impacts in terms of nutrient loads than the Sundays River Estuary. A shift in nutrient concentration trends and system properties occurred between conditions of low and high riverine flow rates. The Swartkops River and Sundays River Estuaries were shown to be ‘outwellers’ of DIN and DIP, while having an important influence on the ratio of DIN:DIP exported to the adjacent ocean. Comparisons with other estuaries suggested that riverine flow into estuaries in the Eastern Cape region may display natural DIN:DIP ratios which are lower than the global average for “pristine” systems. Such ratios would be decreased further by increased water extraction for human activities.
- Full Text:
- Date Issued: 2008
Water quality, abalone growth and the potential for integrated mariculture on a South African abalone Haliotis midae L. farm
- Authors: Yearsley, Rowan David
- Date: 2008
- Subjects: Abalones -- South Africa Abalone culture -- South Africa Abalones -- Growth Mariculture -- South Africa Water quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5334 , http://hdl.handle.net/10962/d1005180
- Description: Abalone Haliotis midae farming in South Africa is highly intensive, employing pump-ashore, flow-through systems. Despite the known sensitivity of abalone to water quality, there is only a rudimentary understanding of water quality dynamics on South African abalone farms and its effects on abalone production. Furthermore, the potential for reusing the relatively dilute abalone farm effluent to culture other animal species has not been investigated. This study investigated the dynamics of water quality and growth on a South African abalone farm and assessed the suitability of the effluent for the culture of silver kob Argyrosomus inodorus and bloodworm Arenicola loveni loveni. Monitoring of water quality and abalone growth in abalone tanks revealed that oxygen concentrations decreased, while H⁺ ion and free-ammonia (NH₃) concentration increased in a gradient between the inflow and outflow. Abalone growth was positively correlated with oxygen concentration and negatively correlated with free-ammonia and H⁺ ion concentration. The oxygen (O) concentration of the farm influent was dependent upon the influents’ temperature (T) and was described by the relationship O (mg L⁻¹) = 11.244 – 0.208T (r²=0.74). Linear regression analysis of data collected from abalone farm tanks revealed that the concentration of total ammonia at the outflow of abalone tanks (μg TAN L⁻¹) was dependant upon temperature (°C), flow-rate (L s⁻¹ kg⁻¹ H. midae), abalone size (g) and length of time since the tank was last cleaned (d) (n = 125, r² = 0.80). The production of total ammonia (μg TAN s⁻¹ kg⁻¹) was related to temperature, abalone size and days that the tanks remained un-cleaned (n = 125; r² = 0.81). A diurnal cycle of respiration was evident in abalone tanks with higher oxygen consumption and H+ ion production at night. The oxygen concentration of farm effluent was related to temperature, farm biomass and flow rate by means of a linear regression equation (n = 40; r² = 0.69). The results demonstrated the importance of optimising the flow-rate per unit of biomass for various temperatures and sizes of abalone. As abalone size and temperature cannot be controlled under farm conditions, the flow-rate per unit of biomass which the abalone culture system receives will determine the quality of the culture water. The specific growth rate (0.48 ± 0.01 % BW d⁻¹), mortality (1.8 ± 0.5 %), feed conversion ratio (3.0 ± 0.2) and protein efficiency ratio (1.0 ± 0.1) of silver kob kept in either abalone farm effluent or control seawater for 120 days did not differ significantly (t-test, P>0.05). A 90 day growth trial indicated that abalone farm effluent is a suitable culture medium for bloodworm. Bloodworm supplied with control seawater lost weight at 0.19 ± 0.04 % BW d-1, while those given abalone effluent grew at 0.39 ± 0.07 % BW d⁻¹. Mortality was 6 ± 3 % in effluent and 11 ± 8 % in seawater. The bloodworm were efficient at processing solid waste. Abalone farm effluent initially contained 7.7 ± 13 mg L⁻¹ more suspended solids than control seawater, which contained 3.5 ± 0.5 mg L⁻¹, but after passing through bloodworm systems the concentration in abalone effluent was reduced to only 1.4 ± 3.5 mg L⁻¹ above that in control seawater. Therefore, abalone farm effluent could be reused as a culture medium for both silver kob and bloodworm. Future work is needed to investigate aspects of the feasibility of such systems such as growth rates at different sizes and stocking densities.
- Full Text:
- Date Issued: 2008
- Authors: Yearsley, Rowan David
- Date: 2008
- Subjects: Abalones -- South Africa Abalone culture -- South Africa Abalones -- Growth Mariculture -- South Africa Water quality -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5334 , http://hdl.handle.net/10962/d1005180
- Description: Abalone Haliotis midae farming in South Africa is highly intensive, employing pump-ashore, flow-through systems. Despite the known sensitivity of abalone to water quality, there is only a rudimentary understanding of water quality dynamics on South African abalone farms and its effects on abalone production. Furthermore, the potential for reusing the relatively dilute abalone farm effluent to culture other animal species has not been investigated. This study investigated the dynamics of water quality and growth on a South African abalone farm and assessed the suitability of the effluent for the culture of silver kob Argyrosomus inodorus and bloodworm Arenicola loveni loveni. Monitoring of water quality and abalone growth in abalone tanks revealed that oxygen concentrations decreased, while H⁺ ion and free-ammonia (NH₃) concentration increased in a gradient between the inflow and outflow. Abalone growth was positively correlated with oxygen concentration and negatively correlated with free-ammonia and H⁺ ion concentration. The oxygen (O) concentration of the farm influent was dependent upon the influents’ temperature (T) and was described by the relationship O (mg L⁻¹) = 11.244 – 0.208T (r²=0.74). Linear regression analysis of data collected from abalone farm tanks revealed that the concentration of total ammonia at the outflow of abalone tanks (μg TAN L⁻¹) was dependant upon temperature (°C), flow-rate (L s⁻¹ kg⁻¹ H. midae), abalone size (g) and length of time since the tank was last cleaned (d) (n = 125, r² = 0.80). The production of total ammonia (μg TAN s⁻¹ kg⁻¹) was related to temperature, abalone size and days that the tanks remained un-cleaned (n = 125; r² = 0.81). A diurnal cycle of respiration was evident in abalone tanks with higher oxygen consumption and H+ ion production at night. The oxygen concentration of farm effluent was related to temperature, farm biomass and flow rate by means of a linear regression equation (n = 40; r² = 0.69). The results demonstrated the importance of optimising the flow-rate per unit of biomass for various temperatures and sizes of abalone. As abalone size and temperature cannot be controlled under farm conditions, the flow-rate per unit of biomass which the abalone culture system receives will determine the quality of the culture water. The specific growth rate (0.48 ± 0.01 % BW d⁻¹), mortality (1.8 ± 0.5 %), feed conversion ratio (3.0 ± 0.2) and protein efficiency ratio (1.0 ± 0.1) of silver kob kept in either abalone farm effluent or control seawater for 120 days did not differ significantly (t-test, P>0.05). A 90 day growth trial indicated that abalone farm effluent is a suitable culture medium for bloodworm. Bloodworm supplied with control seawater lost weight at 0.19 ± 0.04 % BW d-1, while those given abalone effluent grew at 0.39 ± 0.07 % BW d⁻¹. Mortality was 6 ± 3 % in effluent and 11 ± 8 % in seawater. The bloodworm were efficient at processing solid waste. Abalone farm effluent initially contained 7.7 ± 13 mg L⁻¹ more suspended solids than control seawater, which contained 3.5 ± 0.5 mg L⁻¹, but after passing through bloodworm systems the concentration in abalone effluent was reduced to only 1.4 ± 3.5 mg L⁻¹ above that in control seawater. Therefore, abalone farm effluent could be reused as a culture medium for both silver kob and bloodworm. Future work is needed to investigate aspects of the feasibility of such systems such as growth rates at different sizes and stocking densities.
- Full Text:
- Date Issued: 2008
Walter Oakley West (1930-2007) : obituary
- Authors: Lewis, Colin A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6703 , http://hdl.handle.net/10962/d1006739
- Full Text:
- Date Issued: 2008
- Authors: Lewis, Colin A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6703 , http://hdl.handle.net/10962/d1006739
- Full Text:
- Date Issued: 2008
Volcano correlations for the reactivity of surface-confined cobalt N4-macrocyclics for the electrocatalytic oxidation of 2-mercaptoacetate
- Claußen, Jan A, Ochoa, Gonzalo, Páez, Maritza, Costamagno, Juan, Gulppi, Miguel, Nyokong, Tebello, Bedioui, Fethi, Zagal, José H
- Authors: Claußen, Jan A , Ochoa, Gonzalo , Páez, Maritza , Costamagno, Juan , Gulppi, Miguel , Nyokong, Tebello , Bedioui, Fethi , Zagal, José H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268688 , vital:54222 , xlink:href="https://doi.org/10.1007/s10008-007-0336-y"
- Description: We have investigated the electrocatalytic activity of several substituted and unsubstituted cobalt–phthalocyanines of substituted tetraphenyl porphyrins and of vitamin B12, for the electro-oxidation of 2-mercaptoacetate, with the complexes pre-adsorbed on a pyrolytic graphite electrode. Several N4-macrocyclic were used to have a wide variety of Co(II)/(I) formal potentials. The electrocatalytic activity, measured as current at constant potential, increases with the Co(II)/(I) redox potential for porphyrins as Co–pentafluorotetraphenylporphyrin larger than Co–tetrasulfonatotetraphenylporphyrin larger than Co-2,2′,2″,2‴tetra-aminotetraphenylporphyrin and decreases for cobalt phthalocyanines as Co-3,4-octaethylhexyloxyphthalocyanine > Co–octamethoxyphthalocyanine > Co–tetranitrophthalocyanine Co–tetraaminophthalocyanine > Co–unsubstituted phthalocyanine > Co–tetrasulfonatophthalocyanine > Co–perfluorinated phthalocyanine. Vitamin B12 exhibits the maximum activity. A correlation of log I (at constant potential) versus the Co(II)/(I) formal potential of the catalysts gives a volcano curve. This clearly shows that the search for better catalysts for this reaction point to those N4-macrocyclic complexes with Co(II)/(I) formal potentials close to −0.84 V versus SCE, which correspond to an optimum situation for the interaction of the thiol with the active site.
- Full Text:
- Date Issued: 2008
- Authors: Claußen, Jan A , Ochoa, Gonzalo , Páez, Maritza , Costamagno, Juan , Gulppi, Miguel , Nyokong, Tebello , Bedioui, Fethi , Zagal, José H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268688 , vital:54222 , xlink:href="https://doi.org/10.1007/s10008-007-0336-y"
- Description: We have investigated the electrocatalytic activity of several substituted and unsubstituted cobalt–phthalocyanines of substituted tetraphenyl porphyrins and of vitamin B12, for the electro-oxidation of 2-mercaptoacetate, with the complexes pre-adsorbed on a pyrolytic graphite electrode. Several N4-macrocyclic were used to have a wide variety of Co(II)/(I) formal potentials. The electrocatalytic activity, measured as current at constant potential, increases with the Co(II)/(I) redox potential for porphyrins as Co–pentafluorotetraphenylporphyrin larger than Co–tetrasulfonatotetraphenylporphyrin larger than Co-2,2′,2″,2‴tetra-aminotetraphenylporphyrin and decreases for cobalt phthalocyanines as Co-3,4-octaethylhexyloxyphthalocyanine > Co–octamethoxyphthalocyanine > Co–tetranitrophthalocyanine Co–tetraaminophthalocyanine > Co–unsubstituted phthalocyanine > Co–tetrasulfonatophthalocyanine > Co–perfluorinated phthalocyanine. Vitamin B12 exhibits the maximum activity. A correlation of log I (at constant potential) versus the Co(II)/(I) formal potential of the catalysts gives a volcano curve. This clearly shows that the search for better catalysts for this reaction point to those N4-macrocyclic complexes with Co(II)/(I) formal potentials close to −0.84 V versus SCE, which correspond to an optimum situation for the interaction of the thiol with the active site.
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- Date Issued: 2008