Host relations of Kalaharituber pfeilii (Henn.) Trappe & Kagan-Zur
- Authors: Ntshakaza, Pamella
- Date: 2014
- Subjects: Ascomycetes -- Kalahari Desert , Medicinal plants -- Kalahari Desert , Edible fungi -- Kalahari Desert , Truffles -- Kalahari Desert , Desert plants -- Kalahari Desert , Mycorrhizas -- Kalahari Desert , Stipa -- Kalahari Desert
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4167 , http://hdl.handle.net/10962/d1020888
- Description: Kalaharituber pfeilii (Henn.) Trappe & Kagan-Zur commonly known as the “Kalahari truffle” is a desert truffle species identified from the Kalahari region of southern Africa. Two other species, Eremiomyces echinulatus (Trappe & Marasas) Trappe & Kagan-Zur and Mattirolomyces austroafricanus (Trappe & Marasas) Trappe & Kovacs are also known to occur in other parts of southern Africa. Truffles are hypogeous fruiting bodies of Ascomycetes, important to humans for their nutritional value and medicinal characteristics. These truffles are known as desert truffles as they prefer to occur under arid or semi-arid conditions characteristic of deserts. Truffle development depends on the presence of a mycorrhizal host, associated microorganisms as well as soil and climatic characteristics. It has been suggested that K. pfeilii has a suspected broad plant host range which includes herbaceous to woody trees and shrubs. However, these relationships have not been verified. Indigenous people of the Kalahari believe that truffles are found under grasses. In the Kalahari, truffle fruiting bodies are often found entangled in Stipagrostis ciliata (Desf.) De Winter var. capensis (Trin. & Rupr.) De Winter roots. S. ciliata, also known as the tall bushman-grass, is the most common grass found in the Kalahari. The objective of this study was to provide conclusive evidence that S. ciliata var. capensis is a host of the Kalahari truffle. Truffle fruiting bodies and grass roots from where the truffles were found were collected from Upington, South Africa. The fruiting bodies were identified by observing their morphological characteristics using the ‘Keys of Truffle genera’. All observed physical properties were similar to those of K. pfeilii and further identification was done using molecular techniques. DNA was extracted from the fruiting bodies, mycelial cultures, rhizosheaths and from the S. ciliata var. capensis grass roots, which were then amplified using the specific K. pfeilii specific primers TPF3 and TPR1 and sequenced. The obtained sequence results confirmed that the collected fruiting bodies were those of the K. pfeilii and the molecular techniques also confirmed that K. pfeilii DNA was present in the S. ciliata var. capensis rhizosheath and root cells. Microscopy showed an ectendomycorrhizal association between K. pfeilii and S. ciliata var. capensis. Mycorrhizal resynthesis experiments were conducted to establish this mycorrhizal association in-vitro. They were unsuccessful because of the structure of the grass and the availability of contaminants. And more...
- Full Text:
- Date Issued: 2014
- Authors: Ntshakaza, Pamella
- Date: 2014
- Subjects: Ascomycetes -- Kalahari Desert , Medicinal plants -- Kalahari Desert , Edible fungi -- Kalahari Desert , Truffles -- Kalahari Desert , Desert plants -- Kalahari Desert , Mycorrhizas -- Kalahari Desert , Stipa -- Kalahari Desert
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4167 , http://hdl.handle.net/10962/d1020888
- Description: Kalaharituber pfeilii (Henn.) Trappe & Kagan-Zur commonly known as the “Kalahari truffle” is a desert truffle species identified from the Kalahari region of southern Africa. Two other species, Eremiomyces echinulatus (Trappe & Marasas) Trappe & Kagan-Zur and Mattirolomyces austroafricanus (Trappe & Marasas) Trappe & Kovacs are also known to occur in other parts of southern Africa. Truffles are hypogeous fruiting bodies of Ascomycetes, important to humans for their nutritional value and medicinal characteristics. These truffles are known as desert truffles as they prefer to occur under arid or semi-arid conditions characteristic of deserts. Truffle development depends on the presence of a mycorrhizal host, associated microorganisms as well as soil and climatic characteristics. It has been suggested that K. pfeilii has a suspected broad plant host range which includes herbaceous to woody trees and shrubs. However, these relationships have not been verified. Indigenous people of the Kalahari believe that truffles are found under grasses. In the Kalahari, truffle fruiting bodies are often found entangled in Stipagrostis ciliata (Desf.) De Winter var. capensis (Trin. & Rupr.) De Winter roots. S. ciliata, also known as the tall bushman-grass, is the most common grass found in the Kalahari. The objective of this study was to provide conclusive evidence that S. ciliata var. capensis is a host of the Kalahari truffle. Truffle fruiting bodies and grass roots from where the truffles were found were collected from Upington, South Africa. The fruiting bodies were identified by observing their morphological characteristics using the ‘Keys of Truffle genera’. All observed physical properties were similar to those of K. pfeilii and further identification was done using molecular techniques. DNA was extracted from the fruiting bodies, mycelial cultures, rhizosheaths and from the S. ciliata var. capensis grass roots, which were then amplified using the specific K. pfeilii specific primers TPF3 and TPR1 and sequenced. The obtained sequence results confirmed that the collected fruiting bodies were those of the K. pfeilii and the molecular techniques also confirmed that K. pfeilii DNA was present in the S. ciliata var. capensis rhizosheath and root cells. Microscopy showed an ectendomycorrhizal association between K. pfeilii and S. ciliata var. capensis. Mycorrhizal resynthesis experiments were conducted to establish this mycorrhizal association in-vitro. They were unsuccessful because of the structure of the grass and the availability of contaminants. And more...
- Full Text:
- Date Issued: 2014
How are the messages of the official grade ten sexuality education curriculum at a former model C girls' high school in South Africa mediated by student sexual cultures?
- Mthatyana, Andisiwe Tutula Zinzi
- Authors: Mthatyana, Andisiwe Tutula Zinzi
- Date: 2014
- Subjects: Sex instruction -- South Africa , Sex instruction -- Cross-cultural studies , Teenage pregnancy -- South Africa , High school girls -- Sexual behavior -- South Africa , Multicultural education -- South Africa , Model C schools (South Africa) , Girls' schools -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2883 , http://hdl.handle.net/10962/d1013262
- Description: The increase in teenage pregnancy among school going learners is reported in the media as a crisis. Politicians and other stakeholders have also raised their views and concerns about pregnancy. In particular, these views and concerns perceive teenage pregnancy among school going learners as a cancer that needs a remedy because it has negative consequences for the learners, in particular the girl child. However, for all the sense of public crisis concerning sexuality and schooling, the voices of young people themselves regarding their own sexual subjectivity are seldom heard. This study focused on how girls in a former model C all girls high school negotiate and make sense of the meaning of the messages that they receive from the formal curriculum. The concept of student sexual cultures was employed in this study. Student sexual cultures are the informal groups that exist in the school and the girls take part in it. It is in these groups that the girls learn about sexuality and also make sense of their own gendered identities. This study employed ethnographic techniques of classroom observation coupled with in-depth interviews, focus groups and solicited narratives in order to understand how the participants experience and "take up" the messages they receive in the formal sexuality education component of the Life Orientation (LO) curriculum. The data was collected over a period of three months and was analysed using a directed content analysis. Four dominant themes emerged from the study. Firstly, the data reveals the school is a space of competing and conflicting discourses of sexuality and the learners are involved in a constant negotiation of the meanings of the messages. Secondly, the data shows the contested and confirmations of learners subjectivity. It shows that learners are regarded as sexual beings both in the formal and informal school cultures but there are limitations around one's sexual subjectivities. Thirdly, the data reveals that the school is a site in which a variety of femininities are reproduced, contested and struggled over. Femininities are constructed in the complex context of the school thus the school emerges as a site in which multiple femininities intersect with class, race and sexuality. Lastly, this study argues for the incorporation of the discourse of erotics in the formal curriculum which allows young people's voices to be heard. This approach (discourse of erotics) can be seen as a process of becoming, which focuses on possibilities of improving sexuality education as opposed to an imposed sexual model that is applied to young people and assumed to be the solution to young people's sexuality.
- Full Text:
- Date Issued: 2014
- Authors: Mthatyana, Andisiwe Tutula Zinzi
- Date: 2014
- Subjects: Sex instruction -- South Africa , Sex instruction -- Cross-cultural studies , Teenage pregnancy -- South Africa , High school girls -- Sexual behavior -- South Africa , Multicultural education -- South Africa , Model C schools (South Africa) , Girls' schools -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2883 , http://hdl.handle.net/10962/d1013262
- Description: The increase in teenage pregnancy among school going learners is reported in the media as a crisis. Politicians and other stakeholders have also raised their views and concerns about pregnancy. In particular, these views and concerns perceive teenage pregnancy among school going learners as a cancer that needs a remedy because it has negative consequences for the learners, in particular the girl child. However, for all the sense of public crisis concerning sexuality and schooling, the voices of young people themselves regarding their own sexual subjectivity are seldom heard. This study focused on how girls in a former model C all girls high school negotiate and make sense of the meaning of the messages that they receive from the formal curriculum. The concept of student sexual cultures was employed in this study. Student sexual cultures are the informal groups that exist in the school and the girls take part in it. It is in these groups that the girls learn about sexuality and also make sense of their own gendered identities. This study employed ethnographic techniques of classroom observation coupled with in-depth interviews, focus groups and solicited narratives in order to understand how the participants experience and "take up" the messages they receive in the formal sexuality education component of the Life Orientation (LO) curriculum. The data was collected over a period of three months and was analysed using a directed content analysis. Four dominant themes emerged from the study. Firstly, the data reveals the school is a space of competing and conflicting discourses of sexuality and the learners are involved in a constant negotiation of the meanings of the messages. Secondly, the data shows the contested and confirmations of learners subjectivity. It shows that learners are regarded as sexual beings both in the formal and informal school cultures but there are limitations around one's sexual subjectivities. Thirdly, the data reveals that the school is a site in which a variety of femininities are reproduced, contested and struggled over. Femininities are constructed in the complex context of the school thus the school emerges as a site in which multiple femininities intersect with class, race and sexuality. Lastly, this study argues for the incorporation of the discourse of erotics in the formal curriculum which allows young people's voices to be heard. This approach (discourse of erotics) can be seen as a process of becoming, which focuses on possibilities of improving sexuality education as opposed to an imposed sexual model that is applied to young people and assumed to be the solution to young people's sexuality.
- Full Text:
- Date Issued: 2014
Characterization of stratified L-topological spaces by convergence of stratified L-filters
- Authors: Orpen, David Lisle
- Date: 2011
- Subjects: Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5402 , http://hdl.handle.net/10962/d1005216 , Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Description: For the case where L is an ecl-premonoid, we explore various characterizations of SL-topological spaces, in particular characterization in terms of a convergence function lim: FS L(X) ! LX. We find we have to introduce a new axiom , L on the lim function in order to completely describe SL-topological spaces, which is not required in the case where L is a frame. We generalize the classical Kowalski and Fischer axioms to the lattice context and examine their relationship to the convergence axioms. We define the category of stratified L-generalized convergence spaces, as a generalization of the classical convergence spaces and investigate conditions under which it contains the category of stratified L-topological spaces as a reflective subcategory. We investigate some subcategories of the category of stratified L-generalized convergence spaces obtained by generalizing various classical convergence axioms.
- Full Text:
- Date Issued: 2011
- Authors: Orpen, David Lisle
- Date: 2011
- Subjects: Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5402 , http://hdl.handle.net/10962/d1005216 , Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Description: For the case where L is an ecl-premonoid, we explore various characterizations of SL-topological spaces, in particular characterization in terms of a convergence function lim: FS L(X) ! LX. We find we have to introduce a new axiom , L on the lim function in order to completely describe SL-topological spaces, which is not required in the case where L is a frame. We generalize the classical Kowalski and Fischer axioms to the lattice context and examine their relationship to the convergence axioms. We define the category of stratified L-generalized convergence spaces, as a generalization of the classical convergence spaces and investigate conditions under which it contains the category of stratified L-topological spaces as a reflective subcategory. We investigate some subcategories of the category of stratified L-generalized convergence spaces obtained by generalizing various classical convergence axioms.
- Full Text:
- Date Issued: 2011
The impact of forest degradation on carbon stocks of forests in the Matiwane area of the Transkei, South Africa
- Authors: Mangwale, Kagiso
- Date: 2011
- Subjects: Forest degradation -- Control -- South Africa -- Transkei , Forest ecology -- South Africa -- Transkei , Carbon sequestration -- South Africa -- Transkei , Forest conservation -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4781 , http://hdl.handle.net/10962/d1012799 , Forest degradation -- Control -- South Africa -- Transkei , Forest ecology -- South Africa -- Transkei , Carbon sequestration -- South Africa -- Transkei , Forest conservation -- South Africa -- Transkei
- Description: This study focused on assessing the condition and creating a carbon inventory of forests in the Matiwane area of the Transkei. This entailed the use of aerial photography in tracing forest cover change from 1942 to 2007 coupled with ground-truthing to assess whether the forests have in any way endured degradation over the years with a potential reduction in carbon stocks as a result. This study revealed both the loss and gain of biomass in the area with a general trend of forests being continuously converted to agricultural fields resulting in reduced forest area, stem density, tree density and carbon loss in different pools of the forests, reflecting that these forests are degraded. The conversion has resulted in the reduction in the number of species from a mean of 11±0.57 species/200m² in intact forests to 1±0.23species/200m² plot in degraded forests. It was also revealed that approximately 5.2 % (791 hectares) of 15 352 hectares of forest area was lost as a result of the conversion of forest land to agricultural fields from 1942 to 2007 with 99 % of the clearing occurring in the last 33 years (1974-2007) and of which 60 % ( 4 77 hectares) occurred from 1995 to 2007, indicating that forest degradation in these forests is on the increase. The assessment also revealed some areas that were nonforest in 1942 that have accumulated woody biomass (BAA), composed mainly of Acacia sp accounting for 51.18 MgC.ha⁻¹ (Megagrams of carbon per hectare) and total carbon stocks of 0.02 TgC (Teragrams of carbon). The degradation of these forests induced a reduction in carbon stocks from 311.68±23.69 MgC.ha⁻¹ (to a soil depth 0-50 cm) in intact forest to 73.46±12.34 MgC.ha⁻¹ in degraded forests. The total carbon stocks in the degraded forests were approximated at 0.06 TgC and the BAA areas 0.02 TgC with 4.7 TgC in intact forests. The degradation of these forests has resulted in the net carbon loss of 0.19 TgC between 1942 and 2007 but 4.76 TgC is still locked in these forests. The large difference in carbon stocks between intact and degraded forests indicated the need to reduce the degradation of these forests to prevent further carbon loss and reduction of the carbon sequestration potential of these forests.
- Full Text:
- Date Issued: 2011
- Authors: Mangwale, Kagiso
- Date: 2011
- Subjects: Forest degradation -- Control -- South Africa -- Transkei , Forest ecology -- South Africa -- Transkei , Carbon sequestration -- South Africa -- Transkei , Forest conservation -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4781 , http://hdl.handle.net/10962/d1012799 , Forest degradation -- Control -- South Africa -- Transkei , Forest ecology -- South Africa -- Transkei , Carbon sequestration -- South Africa -- Transkei , Forest conservation -- South Africa -- Transkei
- Description: This study focused on assessing the condition and creating a carbon inventory of forests in the Matiwane area of the Transkei. This entailed the use of aerial photography in tracing forest cover change from 1942 to 2007 coupled with ground-truthing to assess whether the forests have in any way endured degradation over the years with a potential reduction in carbon stocks as a result. This study revealed both the loss and gain of biomass in the area with a general trend of forests being continuously converted to agricultural fields resulting in reduced forest area, stem density, tree density and carbon loss in different pools of the forests, reflecting that these forests are degraded. The conversion has resulted in the reduction in the number of species from a mean of 11±0.57 species/200m² in intact forests to 1±0.23species/200m² plot in degraded forests. It was also revealed that approximately 5.2 % (791 hectares) of 15 352 hectares of forest area was lost as a result of the conversion of forest land to agricultural fields from 1942 to 2007 with 99 % of the clearing occurring in the last 33 years (1974-2007) and of which 60 % ( 4 77 hectares) occurred from 1995 to 2007, indicating that forest degradation in these forests is on the increase. The assessment also revealed some areas that were nonforest in 1942 that have accumulated woody biomass (BAA), composed mainly of Acacia sp accounting for 51.18 MgC.ha⁻¹ (Megagrams of carbon per hectare) and total carbon stocks of 0.02 TgC (Teragrams of carbon). The degradation of these forests induced a reduction in carbon stocks from 311.68±23.69 MgC.ha⁻¹ (to a soil depth 0-50 cm) in intact forest to 73.46±12.34 MgC.ha⁻¹ in degraded forests. The total carbon stocks in the degraded forests were approximated at 0.06 TgC and the BAA areas 0.02 TgC with 4.7 TgC in intact forests. The degradation of these forests has resulted in the net carbon loss of 0.19 TgC between 1942 and 2007 but 4.76 TgC is still locked in these forests. The large difference in carbon stocks between intact and degraded forests indicated the need to reduce the degradation of these forests to prevent further carbon loss and reduction of the carbon sequestration potential of these forests.
- Full Text:
- Date Issued: 2011
Understanding and improving the residual efficacy of the cryptophlebia leucotreta granulovirus (Cryptogran)
- Authors: Kirkman, Wayne
- Date: 2008
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5794 , http://hdl.handle.net/10962/d1005482 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Description: False codling moth (FCM), Thaumatotibia (=Cryptophlebia) leucotreta (Meyr) (Lepidoptera: Tortricidae), is one of the most important pests on citrus. The Cryptophlebia leucotreta granulovirus (CrleGV) has been developed into a successful biological control agent, registered under the name Cryptogran, and is currently the preferred product for the control of FCM on citrus in South Africa. A prerequisite to the continued success of Cryptogran as a means of controlling false codling moth is to understand the factors affecting field persistence of the virus, and to find ways to improve it. The aim of this study was to gain a clearer understanding of the product and the abiotic and biotic factors affecting its persistence in the field, and to investigate methods to improve this persistence. The effect of UV-irradiation on the virus was determined, and various products were tested as UV protectants in laboratory bioassays. Lignin was the most effective additive, and was tested in several field trials, where it also enhanced the efficacy of Cryptogran. Laboratory trials indicated that Cryptogran is rainfast. Cryptogran applications early in the season had a longer period of residual activity than sprays applied closer to harvest. Daytime applications were less effective that evening sprays. Sprays applied coinciding with peaks in pheromone moth trap catches were more effective than those applied between peaks. Biotic factors influencing persistence were investigated. Residual efficacy was longer when treatments were applied to blocks than as single tree treatments. Attempts were made to quantify the effect of the navel end of a navel orange on the field persistence of Cryptogran. Cryptogran was shown to be compatible with many agricultural chemicals used on citrus. Economic thresholds and various cost-benefit analyses are discussed. A list of practical recommendations to growers was drawn up, and possibilities for future research are presented.
- Full Text:
- Date Issued: 2008
- Authors: Kirkman, Wayne
- Date: 2008
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5794 , http://hdl.handle.net/10962/d1005482 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Description: False codling moth (FCM), Thaumatotibia (=Cryptophlebia) leucotreta (Meyr) (Lepidoptera: Tortricidae), is one of the most important pests on citrus. The Cryptophlebia leucotreta granulovirus (CrleGV) has been developed into a successful biological control agent, registered under the name Cryptogran, and is currently the preferred product for the control of FCM on citrus in South Africa. A prerequisite to the continued success of Cryptogran as a means of controlling false codling moth is to understand the factors affecting field persistence of the virus, and to find ways to improve it. The aim of this study was to gain a clearer understanding of the product and the abiotic and biotic factors affecting its persistence in the field, and to investigate methods to improve this persistence. The effect of UV-irradiation on the virus was determined, and various products were tested as UV protectants in laboratory bioassays. Lignin was the most effective additive, and was tested in several field trials, where it also enhanced the efficacy of Cryptogran. Laboratory trials indicated that Cryptogran is rainfast. Cryptogran applications early in the season had a longer period of residual activity than sprays applied closer to harvest. Daytime applications were less effective that evening sprays. Sprays applied coinciding with peaks in pheromone moth trap catches were more effective than those applied between peaks. Biotic factors influencing persistence were investigated. Residual efficacy was longer when treatments were applied to blocks than as single tree treatments. Attempts were made to quantify the effect of the navel end of a navel orange on the field persistence of Cryptogran. Cryptogran was shown to be compatible with many agricultural chemicals used on citrus. Economic thresholds and various cost-benefit analyses are discussed. A list of practical recommendations to growers was drawn up, and possibilities for future research are presented.
- Full Text:
- Date Issued: 2008
Applicability of a health literacy test from the U.S. in a South African population
- Lecoko, Motlalepule Lebogang Elizabeth
- Authors: Lecoko, Motlalepule Lebogang Elizabeth
- Date: 2001 , 2013-04-29
- Subjects: Literacy , Literacy -- South Africa , Literacy -- Ability testing , Reading -- Ability testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3824 , http://hdl.handle.net/10962/d1005931 , Literacy , Literacy -- South Africa , Literacy -- Ability testing , Reading -- Ability testing
- Description: This thesis investigates the suitability and applicability of a health literacy test from the U.S. in a black, Xhosa-speaking, South African population. The concept of literacy is a controversial one which has been much debated, as it is not easy to classifY people as simply either literate or illiterate. As a result there are a number of definitions of literacy that vary with purpose and culture, but the most common one is that a person is literate if he/she can read and write. Estimating literacy from years of schooling is an inexpensive method but is also unreliable, since people generally read 3 to 5 grades below their stated educational level. This method affords little insight into the ability of patients to adequately function in a health care enviromnent, an ability which is referred to as functional health literacy. A number of health literacy tests such as the REALM (Rapid Estimate of Adult Literacy in Medicine) test have been developed to assess this skill. The REALM test is a word recognition test which places people into a relevant grade range estimate according to the number of words pronounced correctly. It appears to assume understanding of the word if the person is able to read that word correctly. In this project 125 black Xhosa-speaking respondents of varying educational levels who were literate in English were interviewed with the aid of an interpreter. Comprehensive demographic data were collected. Respondents were first asked to read all 66 words aloud during which time pronunciation was checked, and thereafter they were asked to explain each word. It was found that the ability to automatically decode and read the words did not necessarily guarantee comprehension of these words. Many of the words proved to be unfamiliar to the majority of the Xhosa respondents who were able to pronounce them correctly, but could not explain them. These tended to be phonetically transparent words which were therefore more accessible to the unfamiliar reader. This research has proven to be of great value in helping identify such words which should be substituted with simpler words for use in health information materials. A number of words could neither be pronounced nor understood by the population majority and, interestingly, a small group of words could not be pronounced but were satisfactorily explained by some respondents. The results showed an extremely poor correlation between the stated educational level and the REALM grade range estimate. This emphasizes the inappropriateness of years of formal schooling as an indicator of functional health literacy. The criteria were established for deciding cases in which the REALM test could be applied (or succeeds) and when it is inapplicable (or fails). It was found to be inapplicable in 41% of cases which clearly indicates that, in its current form, it is not a valid, reliable test to use in determining health literacy in this English second language population. It can, however, be used as a basis fur the development of a more appropriate test. Recommendations for future research direction are presented and an alternative structure for a health literacy test is suggested. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2001
- Authors: Lecoko, Motlalepule Lebogang Elizabeth
- Date: 2001 , 2013-04-29
- Subjects: Literacy , Literacy -- South Africa , Literacy -- Ability testing , Reading -- Ability testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3824 , http://hdl.handle.net/10962/d1005931 , Literacy , Literacy -- South Africa , Literacy -- Ability testing , Reading -- Ability testing
- Description: This thesis investigates the suitability and applicability of a health literacy test from the U.S. in a black, Xhosa-speaking, South African population. The concept of literacy is a controversial one which has been much debated, as it is not easy to classifY people as simply either literate or illiterate. As a result there are a number of definitions of literacy that vary with purpose and culture, but the most common one is that a person is literate if he/she can read and write. Estimating literacy from years of schooling is an inexpensive method but is also unreliable, since people generally read 3 to 5 grades below their stated educational level. This method affords little insight into the ability of patients to adequately function in a health care enviromnent, an ability which is referred to as functional health literacy. A number of health literacy tests such as the REALM (Rapid Estimate of Adult Literacy in Medicine) test have been developed to assess this skill. The REALM test is a word recognition test which places people into a relevant grade range estimate according to the number of words pronounced correctly. It appears to assume understanding of the word if the person is able to read that word correctly. In this project 125 black Xhosa-speaking respondents of varying educational levels who were literate in English were interviewed with the aid of an interpreter. Comprehensive demographic data were collected. Respondents were first asked to read all 66 words aloud during which time pronunciation was checked, and thereafter they were asked to explain each word. It was found that the ability to automatically decode and read the words did not necessarily guarantee comprehension of these words. Many of the words proved to be unfamiliar to the majority of the Xhosa respondents who were able to pronounce them correctly, but could not explain them. These tended to be phonetically transparent words which were therefore more accessible to the unfamiliar reader. This research has proven to be of great value in helping identify such words which should be substituted with simpler words for use in health information materials. A number of words could neither be pronounced nor understood by the population majority and, interestingly, a small group of words could not be pronounced but were satisfactorily explained by some respondents. The results showed an extremely poor correlation between the stated educational level and the REALM grade range estimate. This emphasizes the inappropriateness of years of formal schooling as an indicator of functional health literacy. The criteria were established for deciding cases in which the REALM test could be applied (or succeeds) and when it is inapplicable (or fails). It was found to be inapplicable in 41% of cases which clearly indicates that, in its current form, it is not a valid, reliable test to use in determining health literacy in this English second language population. It can, however, be used as a basis fur the development of a more appropriate test. Recommendations for future research direction are presented and an alternative structure for a health literacy test is suggested. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2001
The biology of two important by-catch skate species on the Agulhas Bank, South Africa
- Authors: Walmsley, Sarah Ann
- Date: 1997
- Subjects: Skates (Fishes) -- South Africa -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5240 , http://hdl.handle.net/10962/d1005083 , Skates (Fishes) -- South Africa -- Physiology
- Description: Members of the family Rajidae are common components of the demersal trawl fishery, contributing around 1% to the total catch. However, apart from a single species all South African rajids are currently discarded. With demands for new protein sources ever-increasing, it is possible that currently underutilised species, such as the skates will be utilized to a greater extent. Raja wallacei and R.pullopunctata are common trawler by-catch species, ranging along most of the South African coast. The current study allred to further knowledge on the population biology of both species through age and growth, reproductive and feeding studies. The study also allred to assess whether any of the South African skate species show the potential for utilization as a food source. Band counts of vertebral centra were used to determine growth parameters and generate growth curves for males and females of both species. Growth was significantly different between the sexes. In both cases, females grew slower than males but reached a greater asymptotic disc width. As with other elasmobranchs, R.wallacei and R.pullopunctata are long-lived and slow growing. As with all other skates, the study species are oviparous laying large, yolked eggs in tough, leathery cases on the sea bed. The onset of maturity occurs at a large size (approximately 400mm disc width (10-11 years of age) for R.wallacei and 600mm disc width (12-13 years of age) for Rpullopunctata) and is very rapid. The oldest R.wallacei and R.pullopunctata observed were 16 and 18 years of age, respectively. No distinct breeding season was determined and no nursery areas were observed. A large proportion of individuals, especially R.pullopunctata was immature. Both species fed primarily on crustaceans and teleosts with an ontogenetic shift in diet from mysids, amphipods, isopods and bregmatocerids to larger Gnathophis sp., Mursia cristimanus and carid shrimps. Large discrepancies were seen in the diet of animals spatially, temporally and between research and commercially-caught animals. Disc-width frequency data was limited but suggested that both species show preference for depths of 100-300m. Size distribution did not appear to be affected by depth, although the data set was limited. A paucity of large individuals in the catch may indicate that stocks are suffering from growth overfishing by trawling operations. Historical and observer data showed that although skates are common components of the by-catch, the potential for greater use is limited. The biscuit skate, R.straeleni, on the west coast is the only species that could be better utilized. If skates are treated as a single group the potential is increased but this causes problems in assessing stocks.
- Full Text:
- Date Issued: 1997
- Authors: Walmsley, Sarah Ann
- Date: 1997
- Subjects: Skates (Fishes) -- South Africa -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5240 , http://hdl.handle.net/10962/d1005083 , Skates (Fishes) -- South Africa -- Physiology
- Description: Members of the family Rajidae are common components of the demersal trawl fishery, contributing around 1% to the total catch. However, apart from a single species all South African rajids are currently discarded. With demands for new protein sources ever-increasing, it is possible that currently underutilised species, such as the skates will be utilized to a greater extent. Raja wallacei and R.pullopunctata are common trawler by-catch species, ranging along most of the South African coast. The current study allred to further knowledge on the population biology of both species through age and growth, reproductive and feeding studies. The study also allred to assess whether any of the South African skate species show the potential for utilization as a food source. Band counts of vertebral centra were used to determine growth parameters and generate growth curves for males and females of both species. Growth was significantly different between the sexes. In both cases, females grew slower than males but reached a greater asymptotic disc width. As with other elasmobranchs, R.wallacei and R.pullopunctata are long-lived and slow growing. As with all other skates, the study species are oviparous laying large, yolked eggs in tough, leathery cases on the sea bed. The onset of maturity occurs at a large size (approximately 400mm disc width (10-11 years of age) for R.wallacei and 600mm disc width (12-13 years of age) for Rpullopunctata) and is very rapid. The oldest R.wallacei and R.pullopunctata observed were 16 and 18 years of age, respectively. No distinct breeding season was determined and no nursery areas were observed. A large proportion of individuals, especially R.pullopunctata was immature. Both species fed primarily on crustaceans and teleosts with an ontogenetic shift in diet from mysids, amphipods, isopods and bregmatocerids to larger Gnathophis sp., Mursia cristimanus and carid shrimps. Large discrepancies were seen in the diet of animals spatially, temporally and between research and commercially-caught animals. Disc-width frequency data was limited but suggested that both species show preference for depths of 100-300m. Size distribution did not appear to be affected by depth, although the data set was limited. A paucity of large individuals in the catch may indicate that stocks are suffering from growth overfishing by trawling operations. Historical and observer data showed that although skates are common components of the by-catch, the potential for greater use is limited. The biscuit skate, R.straeleni, on the west coast is the only species that could be better utilized. If skates are treated as a single group the potential is increased but this causes problems in assessing stocks.
- Full Text:
- Date Issued: 1997
Computer modelling of the thermal decomposition of solids
- Authors: De la Croix, Annemarie
- Date: 1996
- Subjects: Solids -- Thermal properties -- Computer simulation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4302 , http://hdl.handle.net/10962/d1004960 , Solids -- Thermal properties -- Computer simulation
- Description: Decompositions of solids are typically of the form: A(s) ----> B(s) + gases. Symmetry-controlled routes (based on known and hypothetical crystal structures) for transforming the solid reactant into the solid product were devised as possible decomposition pathways. Lattice energies of the reactants, of the postulated transient intermediate structures and of the final solid products were then estimated by crystal modelling procedures. Profiles of lattice energy changes during the proposed decomposition routes were constructed and any energy barriers were compared with experimental activation energies reported for the thermal decompositions. The crystal modelling was performed with the computer program WMIN. Calculation of the lattice energies involved the development of a model potential for the perfect lattice and the evaluation of the interatomic parameters. The potential was based on the Born model of ionic solids using the Buckingham potential (Ø(r)= Ae⁻r/p - C/r⁶) to describe the short-range energy contribution. Empirical fitting was used to establish reliable interatomic energy parameters. The reliability of the interatomic potentials was assessed by calculating crystal structures and lattice energies (which were not included in the fitting). The particular reactions selected for modelling were the decompositions of the alkaline-earth metal (Ca, Sr, Ba) peroxides and carbonates: M0₂(s) ---> MO(s) + ¹/₂0₂(g) MC0₃(s) ---> MO(s) + CO₂(g)The lattice energies calculated for the known structures were in good agreement with reported values, (except for Ba0₂ and BaC0₃) which provided support for the adequacy of the potential model used. Activation energies calculated for the decomposition of the carbonates were in the correct order but hlgher than experimental values, i. e., 422, 422, 465 and 499 kJ mol̄̄⁻¹ compared to the experimental values of 205, 87(?), 222 and 283 kJ mol̄̄⁻¹ for CaC0₃ (calcite), CaC0₃(aragonite), SrC0₃ and BaC0₃. The values calculated for the peroxides (91 and 100 kJ mol⁻¹ compared to the experimental values of 119 and 185 kJ mol⁻¹ for Sr0₂ and Ba0₂ respectively) were less satisfactory but could be a reflection of the poor structural data used for the peroxides. The significance of this approach to the modelling of solid decompositions is discussed.
- Full Text:
- Date Issued: 1996
- Authors: De la Croix, Annemarie
- Date: 1996
- Subjects: Solids -- Thermal properties -- Computer simulation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4302 , http://hdl.handle.net/10962/d1004960 , Solids -- Thermal properties -- Computer simulation
- Description: Decompositions of solids are typically of the form: A(s) ----> B(s) + gases. Symmetry-controlled routes (based on known and hypothetical crystal structures) for transforming the solid reactant into the solid product were devised as possible decomposition pathways. Lattice energies of the reactants, of the postulated transient intermediate structures and of the final solid products were then estimated by crystal modelling procedures. Profiles of lattice energy changes during the proposed decomposition routes were constructed and any energy barriers were compared with experimental activation energies reported for the thermal decompositions. The crystal modelling was performed with the computer program WMIN. Calculation of the lattice energies involved the development of a model potential for the perfect lattice and the evaluation of the interatomic parameters. The potential was based on the Born model of ionic solids using the Buckingham potential (Ø(r)= Ae⁻r/p - C/r⁶) to describe the short-range energy contribution. Empirical fitting was used to establish reliable interatomic energy parameters. The reliability of the interatomic potentials was assessed by calculating crystal structures and lattice energies (which were not included in the fitting). The particular reactions selected for modelling were the decompositions of the alkaline-earth metal (Ca, Sr, Ba) peroxides and carbonates: M0₂(s) ---> MO(s) + ¹/₂0₂(g) MC0₃(s) ---> MO(s) + CO₂(g)The lattice energies calculated for the known structures were in good agreement with reported values, (except for Ba0₂ and BaC0₃) which provided support for the adequacy of the potential model used. Activation energies calculated for the decomposition of the carbonates were in the correct order but hlgher than experimental values, i. e., 422, 422, 465 and 499 kJ mol̄̄⁻¹ compared to the experimental values of 205, 87(?), 222 and 283 kJ mol̄̄⁻¹ for CaC0₃ (calcite), CaC0₃(aragonite), SrC0₃ and BaC0₃. The values calculated for the peroxides (91 and 100 kJ mol⁻¹ compared to the experimental values of 119 and 185 kJ mol⁻¹ for Sr0₂ and Ba0₂ respectively) were less satisfactory but could be a reflection of the poor structural data used for the peroxides. The significance of this approach to the modelling of solid decompositions is discussed.
- Full Text:
- Date Issued: 1996
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