Bi-Alexandroff spaces
- Authors: Matutu, Phethiwe P
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6782 , http://hdl.handle.net/10962/d1006925
- Description: Bi-Alexandroff spaces are defined as extensions of Alexandroff spaces [1]. Urysohn’s lemma for bi-Alexandroff spaces is used to show that upper and lower cozero sets of bitopological spaces are bi-Alexandroff spaces. An adjunction between bi-Alexandroff spaces and pairwise completely regular bitopological spaces is established.
- Full Text:
- Date Issued: 2007
- Authors: Matutu, Phethiwe P
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6782 , http://hdl.handle.net/10962/d1006925
- Description: Bi-Alexandroff spaces are defined as extensions of Alexandroff spaces [1]. Urysohn’s lemma for bi-Alexandroff spaces is used to show that upper and lower cozero sets of bitopological spaces are bi-Alexandroff spaces. An adjunction between bi-Alexandroff spaces and pairwise completely regular bitopological spaces is established.
- Full Text:
- Date Issued: 2007
GPS TEC and ionosonde TEC over Grahamstown, South Africa: first comparisons
- McKinnell, Lee-Anne, Opperman, Ben D L, Cilliers, Pierre J
- Authors: McKinnell, Lee-Anne , Opperman, Ben D L , Cilliers, Pierre J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6800 , http://hdl.handle.net/10962/d1004163
- Description: The Grahamstown, South Africa (33.3°S, 26.5°E) ionospheric field station operates a UMass Lowell digital pulse ionospheric sounder (Digisonde) and an Ashtech geodetic grade dual frequency GPS receiver. The GPS receiver is owned by Chief Directorate Surveys and Mapping (CDSM) in Cape Town, forms part of the national TrigNet network and was installed in February 2005. The sampling rates of the GPS receiver and Digisonde were set to 1 s and 15 min, respectively. Data from four continuous months, March–June 2005 inclusive, were considered in this initial investigation. Data available from the Grahamstown GPS receiver was limited, and, therefore, only these 4 months have been considered. Total Electron Content (TEC) values were determined from GPS measurements obtained from satellites passing near vertical (within an 80° elevation) to the station. TEC values were obtained from ionograms recorded at times within 5 min of the near vertical GPS measurement. The GPS derived TEC values are referred to as GTEC and the ionogram derived TEC values as ITEC. Comparisons of GTEC and ITEC values are presented in this paper. The differential clock biases of the GPS satellites and receivers are taken into account. The plasmaspheric contribution to the TEC can be inferred from the results, and confirm findings obtained by other groups. This paper describes the groundwork for a procedure that will allow the validation of GPS derived ionospheric information with ionosonde data. This work will be of interest to the International Reference Ionosphere (IRI) community since GPS receivers are becoming recognised as another source for ionospheric information.
- Full Text:
- Date Issued: 2007
- Authors: McKinnell, Lee-Anne , Opperman, Ben D L , Cilliers, Pierre J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6800 , http://hdl.handle.net/10962/d1004163
- Description: The Grahamstown, South Africa (33.3°S, 26.5°E) ionospheric field station operates a UMass Lowell digital pulse ionospheric sounder (Digisonde) and an Ashtech geodetic grade dual frequency GPS receiver. The GPS receiver is owned by Chief Directorate Surveys and Mapping (CDSM) in Cape Town, forms part of the national TrigNet network and was installed in February 2005. The sampling rates of the GPS receiver and Digisonde were set to 1 s and 15 min, respectively. Data from four continuous months, March–June 2005 inclusive, were considered in this initial investigation. Data available from the Grahamstown GPS receiver was limited, and, therefore, only these 4 months have been considered. Total Electron Content (TEC) values were determined from GPS measurements obtained from satellites passing near vertical (within an 80° elevation) to the station. TEC values were obtained from ionograms recorded at times within 5 min of the near vertical GPS measurement. The GPS derived TEC values are referred to as GTEC and the ionogram derived TEC values as ITEC. Comparisons of GTEC and ITEC values are presented in this paper. The differential clock biases of the GPS satellites and receivers are taken into account. The plasmaspheric contribution to the TEC can be inferred from the results, and confirm findings obtained by other groups. This paper describes the groundwork for a procedure that will allow the validation of GPS derived ionospheric information with ionosonde data. This work will be of interest to the International Reference Ionosphere (IRI) community since GPS receivers are becoming recognised as another source for ionospheric information.
- Full Text:
- Date Issued: 2007
Wave exposure effects on population structure and recruitment in the mussel Perna perna suggest regulation primarily through availability of recruits and food, not space
- McQuaid, Christopher D, Lindsay, Tracy L
- Authors: McQuaid, Christopher D , Lindsay, Tracy L
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6968 , http://hdl.handle.net/10962/d1012033
- Description: Recruitment and population structure of Perna perna in low shore mussel beds were investigated over 15 months at six sites along the south coast of South Africa. Initial, subjective classification of sites as wave exposed or wave sheltered (three of each) was confirmed using the dissolution of cement blocks to measure average water flux and dynamometers for maximum wave force. Recruitment occurred throughout the year, but recruit (1–5 mm) densities were significantly higher from January to April 1996 on both shore types. Recruit densities were positively correlated with adult (>15 mm) densities for both shore types (P < 0.05) but the correlations were extremely weak (r 2 < 0.06 in each case). In areas with 100% cover, adult size (mean and maximum lengths) was greater on exposed sites, but density showed the reverse and was negatively correlated with maximum wave strength (r = −0.84). Despite differences in adult densities and sizes, biomass, which is a product of the two, showed no significant difference between the two shore types (ANOVA P > 0.05). Thus wave exposure dramatically affects density, recruitment and mussel size, but not recruitment timing or biomass where there is 100% cover, and mediates a three-way interaction among food supply, larval supply and intraspecific competition for space. In contrast to shores with saturation recruitment, mussel biomass here appears to be limited by recruit supply and constraints of food, especially on sheltered shores, while density is regulated through intraspecific competition for space primarily on exposed shores and at small spatial scales.
- Full Text:
- Date Issued: 2007
- Authors: McQuaid, Christopher D , Lindsay, Tracy L
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6968 , http://hdl.handle.net/10962/d1012033
- Description: Recruitment and population structure of Perna perna in low shore mussel beds were investigated over 15 months at six sites along the south coast of South Africa. Initial, subjective classification of sites as wave exposed or wave sheltered (three of each) was confirmed using the dissolution of cement blocks to measure average water flux and dynamometers for maximum wave force. Recruitment occurred throughout the year, but recruit (1–5 mm) densities were significantly higher from January to April 1996 on both shore types. Recruit densities were positively correlated with adult (>15 mm) densities for both shore types (P < 0.05) but the correlations were extremely weak (r 2 < 0.06 in each case). In areas with 100% cover, adult size (mean and maximum lengths) was greater on exposed sites, but density showed the reverse and was negatively correlated with maximum wave strength (r = −0.84). Despite differences in adult densities and sizes, biomass, which is a product of the two, showed no significant difference between the two shore types (ANOVA P > 0.05). Thus wave exposure dramatically affects density, recruitment and mussel size, but not recruitment timing or biomass where there is 100% cover, and mediates a three-way interaction among food supply, larval supply and intraspecific competition for space. In contrast to shores with saturation recruitment, mussel biomass here appears to be limited by recruit supply and constraints of food, especially on sheltered shores, while density is regulated through intraspecific competition for space primarily on exposed shores and at small spatial scales.
- Full Text:
- Date Issued: 2007
Health, human rights, and the conduct of clinical research within oppressed populations
- Authors: Mills, E J , Singh, S
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6411 , http://hdl.handle.net/10962/d1006504 , http://dx.doi.org/10.1186/1744-8603-3-10
- Description: Background Clinical trials evaluating interventions for infectious diseases require enrolling participants that are vulnerable to infection. As clinical trials are conducted in increasingly vulnerable populations, issues of protection of these populations become challenging. In settings where populations are forseeably oppressed, the conduct of research requires considerations that go beyond common ethical concerns and into issues of international human rights law. Discussion Using examples of HIV prevention trials in Thailand, hepatitis-E prevention trials in Nepal and malaria therapeutic trials in Burma (Myanmar), we address the inadequacies of current ethical guidelines when conducting research within oppressed populations. We review existing legislature in the United States and United Kingdom that may be used against foreign investigators if trial hardships exist. We conclude by making considerations for research conducted within oppressed populations.
- Full Text:
- Date Issued: 2007
- Authors: Mills, E J , Singh, S
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6411 , http://hdl.handle.net/10962/d1006504 , http://dx.doi.org/10.1186/1744-8603-3-10
- Description: Background Clinical trials evaluating interventions for infectious diseases require enrolling participants that are vulnerable to infection. As clinical trials are conducted in increasingly vulnerable populations, issues of protection of these populations become challenging. In settings where populations are forseeably oppressed, the conduct of research requires considerations that go beyond common ethical concerns and into issues of international human rights law. Discussion Using examples of HIV prevention trials in Thailand, hepatitis-E prevention trials in Nepal and malaria therapeutic trials in Burma (Myanmar), we address the inadequacies of current ethical guidelines when conducting research within oppressed populations. We review existing legislature in the United States and United Kingdom that may be used against foreign investigators if trial hardships exist. We conclude by making considerations for research conducted within oppressed populations.
- Full Text:
- Date Issued: 2007
Mapping GPS-derived ionospheric Total Electron Content over Southern Africa during different epochs of solar cycle 23
- Moeketsi, D M, Combrinck, W L, McKinnell, Lee-Anne, Fedrizz, M
- Authors: Moeketsi, D M , Combrinck, W L , McKinnell, Lee-Anne , Fedrizz, M
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6802 , http://hdl.handle.net/10962/d1004165
- Description: The Southern African Development Community and the International Global Navigation Satellite Systems Service (GNSS) network of dual frequency Global Positioning System (GPS) receivers provide an opportunity to determine Total Electron Content (TEC) over Southern Africa by taking advantage of the dispersive nature of the ionospheric medium. For this task, the University of New Brunswick (UNB) ionospheric modelling technique which applies a spatial linear approximation of the vertical TEC above each station using stochastic parameters in Kalman filter estimation, primed with data from the Southern Africa GPS network, was used for mapping TEC at South African locations during selected days and hours of different epochs of solar cycle 23. Significant enhancements in the TEC value and features, which could be associated with frequent solar events, are evident around a day of extreme solar maximum. These observations are discussed and further investigated by analyzing the GOES 8 and 10 satellites X-ray flux (0.1–0.8 nm) and SOHO Solar EUV Monitor (26.0–34.0 nm) higher resolution data. Comparison of these physical quantities reveals that for each X-ray flare observed, there is an associated EUV flare event. The latter phenomenon causes photoionisation in the daytime ionosphere which results in significant TEC enhancement. The daytime UNB TEC compared with the International Reference Ionosphere (IRI) 2001 predicted TEC found both models to show a good agreement.
- Full Text:
- Date Issued: 2007
- Authors: Moeketsi, D M , Combrinck, W L , McKinnell, Lee-Anne , Fedrizz, M
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6802 , http://hdl.handle.net/10962/d1004165
- Description: The Southern African Development Community and the International Global Navigation Satellite Systems Service (GNSS) network of dual frequency Global Positioning System (GPS) receivers provide an opportunity to determine Total Electron Content (TEC) over Southern Africa by taking advantage of the dispersive nature of the ionospheric medium. For this task, the University of New Brunswick (UNB) ionospheric modelling technique which applies a spatial linear approximation of the vertical TEC above each station using stochastic parameters in Kalman filter estimation, primed with data from the Southern Africa GPS network, was used for mapping TEC at South African locations during selected days and hours of different epochs of solar cycle 23. Significant enhancements in the TEC value and features, which could be associated with frequent solar events, are evident around a day of extreme solar maximum. These observations are discussed and further investigated by analyzing the GOES 8 and 10 satellites X-ray flux (0.1–0.8 nm) and SOHO Solar EUV Monitor (26.0–34.0 nm) higher resolution data. Comparison of these physical quantities reveals that for each X-ray flare observed, there is an associated EUV flare event. The latter phenomenon causes photoionisation in the daytime ionosphere which results in significant TEC enhancement. The daytime UNB TEC compared with the International Reference Ionosphere (IRI) 2001 predicted TEC found both models to show a good agreement.
- Full Text:
- Date Issued: 2007
A stability-indicating high performance liquid chromatographic (HPLC) assay for the simultaneous determination of atorvastatin and amlodipine in commercial tablets
- Mohammadi, Ali, Rezanour, N, Ansari Dogaheh, M, Ghorbani Bidkorbeh, F, Hashem, M, Walker, Roderick B
- Authors: Mohammadi, Ali , Rezanour, N , Ansari Dogaheh, M , Ghorbani Bidkorbeh, F , Hashem, M , Walker, Roderick B
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6403 , http://hdl.handle.net/10962/d1006340
- Description: A simple, rapid, precise and accurate isocratic reversed-phase stability-indicating HPLC method was developed and validated for the simultaneous determination of atorvastatin (AT) and amlodipine (AM) in commercial tablets. The method has shown adequate separation for AM, AT from their associated main impurities and their degradation products. Separation was achieved on a Perfectsil® Target ODS-3, 5 μm, 250 mm × 4.6 mm i.d. column using a mobile phase consisting of acetonitrile–0.025 M NaH2PO4 buffer (pH 4.5) (55:45, v/v) at a flow rate of 1 ml/min and UV detection at 237 nm. The drugs were subjected to oxidation, hydrolysis, photolysis and heat to apply stress conditions. The linearity of the proposed method was investigated in the range of 2–30 μg/ml (r = 0.9994) for AT and 1–20 μg/ml (r = 0.9993) for AM. The limits of detection were 0.65 μg/ml and 0.35 μg/ml for AT and AM, respectively. The limits of quantitation were 2 μg/ml and 1 μg/ml for AT and AM, respectively. Degradation products produced as a result of stress studies did not interfere with the detection of AT and AM and the assay can thus be considered stability-indicating.
- Full Text:
- Date Issued: 2007
- Authors: Mohammadi, Ali , Rezanour, N , Ansari Dogaheh, M , Ghorbani Bidkorbeh, F , Hashem, M , Walker, Roderick B
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6403 , http://hdl.handle.net/10962/d1006340
- Description: A simple, rapid, precise and accurate isocratic reversed-phase stability-indicating HPLC method was developed and validated for the simultaneous determination of atorvastatin (AT) and amlodipine (AM) in commercial tablets. The method has shown adequate separation for AM, AT from their associated main impurities and their degradation products. Separation was achieved on a Perfectsil® Target ODS-3, 5 μm, 250 mm × 4.6 mm i.d. column using a mobile phase consisting of acetonitrile–0.025 M NaH2PO4 buffer (pH 4.5) (55:45, v/v) at a flow rate of 1 ml/min and UV detection at 237 nm. The drugs were subjected to oxidation, hydrolysis, photolysis and heat to apply stress conditions. The linearity of the proposed method was investigated in the range of 2–30 μg/ml (r = 0.9994) for AT and 1–20 μg/ml (r = 0.9993) for AM. The limits of detection were 0.65 μg/ml and 0.35 μg/ml for AT and AM, respectively. The limits of quantitation were 2 μg/ml and 1 μg/ml for AT and AM, respectively. Degradation products produced as a result of stress studies did not interfere with the detection of AT and AM and the assay can thus be considered stability-indicating.
- Full Text:
- Date Issued: 2007
Satisfied and dissatisfied South Africans: results from the General Household Survey in international comparison
- Authors: Moller, Valerie
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7112 , http://hdl.handle.net/10962/d1010744
- Description: Who are the satisfied South Africans 10 years into democracy? How do material factors contribute to their life satisfaction? These are the questions addressed in this paper. Earlier South African research has consistently found a close positive relationship between life satisfaction and material standards of living in the apartheid and post-apartheid era. Recently, a new source of information has become available to shed further light on the association between material and subjective well-being. In 2002, Statistics South Africa, the country’s official source of statistical information, agreed to ask South Africans participating in the General Household Survey whether they were satisfied or dissatisfied with life. The 2002 General Household Survey (n26’000) used a measure developed for the Euromodule that allows for international comparison. The wide-ranging information contained in South Africa’s official household survey offers a unique opportunity to explore what makes for satisfied and dissatisfied South Africans in relation to their material living standards. Results indicate that the improved living standards afforded to many black South Africans under democracy are associated with increases in life satisfaction. Furthermore, habituation does not appear to have diluted the positive relationship between living standards and well-being. However, political factors continue to play an important role in shaping subjective well-being. In conclusion, it is argued that material gains might also have restored the pride and dignity denied to black South Africans in the past.
- Full Text:
- Date Issued: 2007
- Authors: Moller, Valerie
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7112 , http://hdl.handle.net/10962/d1010744
- Description: Who are the satisfied South Africans 10 years into democracy? How do material factors contribute to their life satisfaction? These are the questions addressed in this paper. Earlier South African research has consistently found a close positive relationship between life satisfaction and material standards of living in the apartheid and post-apartheid era. Recently, a new source of information has become available to shed further light on the association between material and subjective well-being. In 2002, Statistics South Africa, the country’s official source of statistical information, agreed to ask South Africans participating in the General Household Survey whether they were satisfied or dissatisfied with life. The 2002 General Household Survey (n26’000) used a measure developed for the Euromodule that allows for international comparison. The wide-ranging information contained in South Africa’s official household survey offers a unique opportunity to explore what makes for satisfied and dissatisfied South Africans in relation to their material living standards. Results indicate that the improved living standards afforded to many black South Africans under democracy are associated with increases in life satisfaction. Furthermore, habituation does not appear to have diluted the positive relationship between living standards and well-being. However, political factors continue to play an important role in shaping subjective well-being. In conclusion, it is argued that material gains might also have restored the pride and dignity denied to black South Africans in the past.
- Full Text:
- Date Issued: 2007
Quality of life in South Africa: the first ten years of democracy
- Authors: Moller, Valerie
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7110 , http://hdl.handle.net/10962/d1010741
- Description: South Africa celebrated ten years of democracy in 2004. This special issue of Social Indicators Research (SIR) reviews developments that have impacted on the quality of life of ordinary South Africans during the transition period. The issue updates an earlier volume of SIR (Volume 41) published in 1997 and as a stand-alone volume. The earlier volume was initiated following SIR editor Alex Michalos’ first visit to South Africa. This update on quality of life in South Africa follows on his return visit to the country in 2004 to see firsthand the changes that had occured in the meantime. This introductory article outlines major achievements of and setbacks for the new democracy and the challenges facing it in future. It provides the backround for the evaluations of a range of quality of life domains and issues including poverty and inequality, crime, the HIV/AIDS epidemic, migration and housing, religiosity, reconciliation, and optimism for the future which are covered in the eleven articles that follow. The introduction divides the articles under the headings of challenges, achievements, monitoring quality of life, and social capital for the future. The overview article concludes that improvements in quality of life have been uneven but goodwill and a positive outlook bode well for South African quality of life in future.
- Full Text:
- Date Issued: 2007
- Authors: Moller, Valerie
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7110 , http://hdl.handle.net/10962/d1010741
- Description: South Africa celebrated ten years of democracy in 2004. This special issue of Social Indicators Research (SIR) reviews developments that have impacted on the quality of life of ordinary South Africans during the transition period. The issue updates an earlier volume of SIR (Volume 41) published in 1997 and as a stand-alone volume. The earlier volume was initiated following SIR editor Alex Michalos’ first visit to South Africa. This update on quality of life in South Africa follows on his return visit to the country in 2004 to see firsthand the changes that had occured in the meantime. This introductory article outlines major achievements of and setbacks for the new democracy and the challenges facing it in future. It provides the backround for the evaluations of a range of quality of life domains and issues including poverty and inequality, crime, the HIV/AIDS epidemic, migration and housing, religiosity, reconciliation, and optimism for the future which are covered in the eleven articles that follow. The introduction divides the articles under the headings of challenges, achievements, monitoring quality of life, and social capital for the future. The overview article concludes that improvements in quality of life have been uneven but goodwill and a positive outlook bode well for South African quality of life in future.
- Full Text:
- Date Issued: 2007
Ethnicity and nationalism in urban colonial Zimbabwe : Bulawayo, 1950 to 1963
- Authors: Msindo, Enocent
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6149 , http://hdl.handle.net/10962/d1006813 , http://dx.doi.org/10.1017/S0021853707002538
- Description: Zimbabwean historians have not yet fully assessed the interaction of two problematic identities, ethnicity and nationalism, to determine whether the two can work as partners and successfully co-exist. This essay argues that, in Bulawayo during the period studied, ethnicity co-existed with and complemented nationalism rather than the two working as polar opposite identities. Ethnic groups provided both the required leaders who became prominent nationalist figures and the precolonial history, personalities and monuments that sparked the nationalist imagination. From the 1950s, ethnic groups expanded their horizons and provided platforms from which emerging African nationalists launched their agenda. Understanding these interrelationships will reshape our understanding of the workings of these two identities in a cosmopolitan town.
- Full Text:
- Date Issued: 2007
- Authors: Msindo, Enocent
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6149 , http://hdl.handle.net/10962/d1006813 , http://dx.doi.org/10.1017/S0021853707002538
- Description: Zimbabwean historians have not yet fully assessed the interaction of two problematic identities, ethnicity and nationalism, to determine whether the two can work as partners and successfully co-exist. This essay argues that, in Bulawayo during the period studied, ethnicity co-existed with and complemented nationalism rather than the two working as polar opposite identities. Ethnic groups provided both the required leaders who became prominent nationalist figures and the precolonial history, personalities and monuments that sparked the nationalist imagination. From the 1950s, ethnic groups expanded their horizons and provided platforms from which emerging African nationalists launched their agenda. Understanding these interrelationships will reshape our understanding of the workings of these two identities in a cosmopolitan town.
- Full Text:
- Date Issued: 2007
Development of written information for antiretroviral therapy: comprehension in a Tanzanian population
- Mwingira, Betty, Dowse, Roslind
- Authors: Mwingira, Betty , Dowse, Roslind
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6404 , http://hdl.handle.net/10962/d1006477
- Description: Objective To design and develop a simple, easily readable patient information leaflet (PIL) for a commonly used antiretroviral (ARV) regimen and to evaluate its readability and acceptability in a Tanzanian population. Method A PIL incorporating simple text and pictograms was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz. The PIL was designed according to established good design guidelines, modified during a multi-stage iterative testing process and piloted in a South African Xhosa population. The PIL was made available in both English and Kiswahili. Sixty Tanzanian participants who were not taking ARVs were interviewed. They were asked to read the PIL in the language of their choice and were then asked a series of two-part questions; the first part required participants to locate the information in the PIL, after which they were asked to explain the information in their own words. Acceptability was assessed through close-ended questions and open-ended feedback. The influence of selected patient characteristics on comprehension of the PIL was investigated using one-way ANOVA and t-tests for independent samples with a significance level set at 0.05. Main outcome measure Comprehension of the written information in an overall percentage understanding. Results The overall average percentage comprehension of the PIL was 95%. The target set by the EC guideline that at least 80% of participants correctly locate and understand the information was achieved for 19 of the 20 questions. Five of the six instructions illustrated by pictograms were correctly understood by all participants. The only patient characteristics significantly associated with comprehension were educational level and self-reported ease of reading the PIL. Acceptability of the PIL was high and positive comments were associated with simplicity, good design, easy readability and user-friendliness, the latter enhanced by the inclusion of pictograms. Conclusion The PIL designed for this study was shown to be effective in communicating information about ARVs. Patient characteristics must be taken into account when developing written information, and the final document must be tested for comprehension in the target population.
- Full Text:
- Date Issued: 2007
- Authors: Mwingira, Betty , Dowse, Roslind
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6404 , http://hdl.handle.net/10962/d1006477
- Description: Objective To design and develop a simple, easily readable patient information leaflet (PIL) for a commonly used antiretroviral (ARV) regimen and to evaluate its readability and acceptability in a Tanzanian population. Method A PIL incorporating simple text and pictograms was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz. The PIL was designed according to established good design guidelines, modified during a multi-stage iterative testing process and piloted in a South African Xhosa population. The PIL was made available in both English and Kiswahili. Sixty Tanzanian participants who were not taking ARVs were interviewed. They were asked to read the PIL in the language of their choice and were then asked a series of two-part questions; the first part required participants to locate the information in the PIL, after which they were asked to explain the information in their own words. Acceptability was assessed through close-ended questions and open-ended feedback. The influence of selected patient characteristics on comprehension of the PIL was investigated using one-way ANOVA and t-tests for independent samples with a significance level set at 0.05. Main outcome measure Comprehension of the written information in an overall percentage understanding. Results The overall average percentage comprehension of the PIL was 95%. The target set by the EC guideline that at least 80% of participants correctly locate and understand the information was achieved for 19 of the 20 questions. Five of the six instructions illustrated by pictograms were correctly understood by all participants. The only patient characteristics significantly associated with comprehension were educational level and self-reported ease of reading the PIL. Acceptability of the PIL was high and positive comments were associated with simplicity, good design, easy readability and user-friendliness, the latter enhanced by the inclusion of pictograms. Conclusion The PIL designed for this study was shown to be effective in communicating information about ARVs. Patient characteristics must be taken into account when developing written information, and the final document must be tested for comprehension in the target population.
- Full Text:
- Date Issued: 2007
South Asian diasporic women's short fiction: the South African contribution
- Authors: Naidu, Samantha
- Date: 2007
- Language: English
- Type: Article , text
- Identifier: vital:26376 , http://hdl.handle.net/10962/54037 , https://orcid.org/0000-0001-9456-8657
- Description: Although Indian Women S Short Fiction Has Always Enjoyed Equal Importance And Popularity As Their Novels, Very Little Critical Attention Has Been Paid To It So Far. Indian Women S Short Fiction Seeks To Fulfil This Long Felt Need. It Puts Together Fifteen Perceptive And Analytical Articles By Scholars Across The World. The Articles, Which Are Focussed On Native Indian Writing As Well As Diasporic Short Fiction, Deal With Such Interesting Literary Issues As Construction Of Femininity, Disablement And Enablement, Bengali Heritage, Hybrid Identities, Nostalgia, Representation Of The Partition Violence, Tradition And Modernity, And Cultural Perspectivism.
- Full Text: false
- Date Issued: 2007
- Authors: Naidu, Samantha
- Date: 2007
- Language: English
- Type: Article , text
- Identifier: vital:26376 , http://hdl.handle.net/10962/54037 , https://orcid.org/0000-0001-9456-8657
- Description: Although Indian Women S Short Fiction Has Always Enjoyed Equal Importance And Popularity As Their Novels, Very Little Critical Attention Has Been Paid To It So Far. Indian Women S Short Fiction Seeks To Fulfil This Long Felt Need. It Puts Together Fifteen Perceptive And Analytical Articles By Scholars Across The World. The Articles, Which Are Focussed On Native Indian Writing As Well As Diasporic Short Fiction, Deal With Such Interesting Literary Issues As Construction Of Femininity, Disablement And Enablement, Bengali Heritage, Hybrid Identities, Nostalgia, Representation Of The Partition Violence, Tradition And Modernity, And Cultural Perspectivism.
- Full Text: false
- Date Issued: 2007
Karyology of three evolutionarily hexaploid southern African species of yellowfish, Labeobarbus Rüppel, 1836 (Cyprinidae)
- Naran, D, Skelton, Paul H, Villet, Martin H
- Authors: Naran, D , Skelton, Paul H , Villet, Martin H
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6855 , http://hdl.handle.net/10962/d1011138 , http://dx.doi.org/10.3377/1562-7020(2007)42[254:KOTEHS]2.0.CO;2
- Description: The karyotypes of three species of yellowfish, namely Labeobarbus marequensis (A. Smith, 1841), L. capensis (A. Smith, 1841) and L. polylepis (Boulenger, 1907), were examined by Giemsa staining using an approach improved for the description of high chromosome numbers. In each case, 2n = 150; no heteromorphic chromosomes were detected; chromosomes in all morphological categories ranged smoothly from large to small, with no distinctly large submetacentric pairs; and metacentric chromosomes showed little variation in size. Labeobarbus marequensis had 26 metacentric (m), 44 submetacentric (sm), 42 subtelocentric (st) and 38 acrocentric (a) chromosomes and a fundamental number (FN) of 262; L. capensis had 16 m, 58 sm, 42 st and 34 a chromosomes and FN = 266; and L. polylepis had 18 m, 60 sm, 42 st and 30 a chromosomes and FN = 270. These results, combined with published literature, imply that Labeobarbus Rüppel, 1836 is an evolutionarily hexaploid African lineage and support its removal from synonymy with the evolutionarily tetraploid Asian genus Tor Gray, 1834. A review of fundamental numbers for conspecific Labeobarbus species examined in different studies implicated karyological technique as a confounding factor in assessing details of karyotypes, leading to recommendations for future karyological studies of barbine fishes. Potential synapomorphies are pointed out in karyological characters of species within Labeobarbus.
- Full Text:
- Date Issued: 2007
- Authors: Naran, D , Skelton, Paul H , Villet, Martin H
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6855 , http://hdl.handle.net/10962/d1011138 , http://dx.doi.org/10.3377/1562-7020(2007)42[254:KOTEHS]2.0.CO;2
- Description: The karyotypes of three species of yellowfish, namely Labeobarbus marequensis (A. Smith, 1841), L. capensis (A. Smith, 1841) and L. polylepis (Boulenger, 1907), were examined by Giemsa staining using an approach improved for the description of high chromosome numbers. In each case, 2n = 150; no heteromorphic chromosomes were detected; chromosomes in all morphological categories ranged smoothly from large to small, with no distinctly large submetacentric pairs; and metacentric chromosomes showed little variation in size. Labeobarbus marequensis had 26 metacentric (m), 44 submetacentric (sm), 42 subtelocentric (st) and 38 acrocentric (a) chromosomes and a fundamental number (FN) of 262; L. capensis had 16 m, 58 sm, 42 st and 34 a chromosomes and FN = 266; and L. polylepis had 18 m, 60 sm, 42 st and 30 a chromosomes and FN = 270. These results, combined with published literature, imply that Labeobarbus Rüppel, 1836 is an evolutionarily hexaploid African lineage and support its removal from synonymy with the evolutionarily tetraploid Asian genus Tor Gray, 1834. A review of fundamental numbers for conspecific Labeobarbus species examined in different studies implicated karyological technique as a confounding factor in assessing details of karyotypes, leading to recommendations for future karyological studies of barbine fishes. Potential synapomorphies are pointed out in karyological characters of species within Labeobarbus.
- Full Text:
- Date Issued: 2007
'Alternative foods' and community-based development : Rooibos tea production in South Africa's West Coast mountains
- Nel, Etienne L, Binns, Tony, Bek, David
- Authors: Nel, Etienne L , Binns, Tony , Bek, David
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6718 , http://hdl.handle.net/10962/d1006791
- Description: Rooibos tee (red bush tea) (Aspalathus linearis, Fabaceae), which is indigenous only to the Cedarberg and neighbouring mountains of South Africa, has become popular internationally as a result of its apparent health-giving properties. Situated within the broader contexts of alternative food networks, alternate economic spaces and local/community-based development, this paper examines how two marginalised communities have successfully penetrated international markets by supplying organically produced rooibos tea which is certified by the international Fairtrade system. Focusing on the cases of Wupperthal and Heiveld, the paper explores the dynamics of the production and marketing process and the key variables involved. Success has been achieved through active NGO support, which has engaged with local skills and social capital, and has led to significant social and economic upliftment among the participating communities. The experience illustrates how, given the right conditions, poor communities in the South might participate successfully in global alternative food networks.
- Full Text:
- Date Issued: 2007
- Authors: Nel, Etienne L , Binns, Tony , Bek, David
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6718 , http://hdl.handle.net/10962/d1006791
- Description: Rooibos tee (red bush tea) (Aspalathus linearis, Fabaceae), which is indigenous only to the Cedarberg and neighbouring mountains of South Africa, has become popular internationally as a result of its apparent health-giving properties. Situated within the broader contexts of alternative food networks, alternate economic spaces and local/community-based development, this paper examines how two marginalised communities have successfully penetrated international markets by supplying organically produced rooibos tea which is certified by the international Fairtrade system. Focusing on the cases of Wupperthal and Heiveld, the paper explores the dynamics of the production and marketing process and the key variables involved. Success has been achieved through active NGO support, which has engaged with local skills and social capital, and has led to significant social and economic upliftment among the participating communities. The experience illustrates how, given the right conditions, poor communities in the South might participate successfully in global alternative food networks.
- Full Text:
- Date Issued: 2007
Cytosolic and ER J-domains of mammalian and parasitic origin can functionally interact with DnaK
- Nicoll, W S, Botha, M, McNamara, Caryn, Schlange, M, Pesce, E R, Boshoff, Aileen, Ludewig, M H, Zimmerman, R, Cheetham, M E, Chapple, J P, Blatch, Gregory L
- Authors: Nicoll, W S , Botha, M , McNamara, Caryn , Schlange, M , Pesce, E R , Boshoff, Aileen , Ludewig, M H , Zimmerman, R , Cheetham, M E , Chapple, J P , Blatch, Gregory L
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6484 , http://hdl.handle.net/10962/d1006261 , http://www.sciencedirect.com/science/article/pii/S1357272506003268
- Description: Both prokaryotic and eukaryotic cells contain multiple heat shock protein 40 (Hsp40) and heat shock protein 70 (Hsp70) proteins, which cooperate as molecular chaperones to ensure fidelity at all stages of protein biogenesis. The Hsp40 signature domain, the J-domain, is required for binding of an Hsp40 to a partner Hsp70, and may also play a role in the specificity of the association. Through the creation of chimeric Hsp40 proteins by the replacement of the J-domain of a prokaryotic Hsp40 (DnaJ), we have tested the functional equivalence of J-domains from a number of divergent Hsp40s of mammalian and parasitic origin (malarial Pfj1 and Pfj4, trypanosomal Tcj3, human ERj3, ERj5, and Hsj1, and murine ERj1). An in vivo functional assay was used to test the functionality of the chimeric proteins on the basis of their ability to reverse the thermosensitivity of a dnaJ cbpA mutant Escherichia coli strain (OD259). The Hsp40 chimeras containing J-domains originating from soluble (cytosolic or endoplasmic reticulum (ER)-lumenal) Hsp40s were able to reverse the thermosensitivity of E. coli OD259. In all cases, modified derivatives of these chimeric proteins containing an His to Gln substitution in the HPD motif of the J-domain were unable to reverse the thermosensitivity of E. coli OD259. This suggested that these J-domains exerted their in vivo functionality through a specific interaction with E. coli Hsp70, DnaK. Interestingly, a Hsp40 chimera containing the J-domain of ERj1, an integral membrane-bound ER Hsp40, was unable to reverse the thermosensitivity of E. coli OD259, suggesting that this J-domain was unable to functionally interact with DnaK. Substitutions of conserved amino acid residues and motifs were made in all four helices (I-IV) and the loop regions of the J-domains, and the modified chimeric Hsp40s were tested for functionality using the in vivo assay. Substitution of a highly conserved basic residue in helix II of the J-domain was found to disrupt in vivo functionality for all the J-domains tested. We propose that helix II and the HPD motif of the J-domain represent the fundamental elements of a binding surface required for the interaction of Hsp40s with Hsp70s, and that this surface has been conserved in mammalian, parasitic and bacterial systems.
- Full Text:
- Date Issued: 2007
- Authors: Nicoll, W S , Botha, M , McNamara, Caryn , Schlange, M , Pesce, E R , Boshoff, Aileen , Ludewig, M H , Zimmerman, R , Cheetham, M E , Chapple, J P , Blatch, Gregory L
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6484 , http://hdl.handle.net/10962/d1006261 , http://www.sciencedirect.com/science/article/pii/S1357272506003268
- Description: Both prokaryotic and eukaryotic cells contain multiple heat shock protein 40 (Hsp40) and heat shock protein 70 (Hsp70) proteins, which cooperate as molecular chaperones to ensure fidelity at all stages of protein biogenesis. The Hsp40 signature domain, the J-domain, is required for binding of an Hsp40 to a partner Hsp70, and may also play a role in the specificity of the association. Through the creation of chimeric Hsp40 proteins by the replacement of the J-domain of a prokaryotic Hsp40 (DnaJ), we have tested the functional equivalence of J-domains from a number of divergent Hsp40s of mammalian and parasitic origin (malarial Pfj1 and Pfj4, trypanosomal Tcj3, human ERj3, ERj5, and Hsj1, and murine ERj1). An in vivo functional assay was used to test the functionality of the chimeric proteins on the basis of their ability to reverse the thermosensitivity of a dnaJ cbpA mutant Escherichia coli strain (OD259). The Hsp40 chimeras containing J-domains originating from soluble (cytosolic or endoplasmic reticulum (ER)-lumenal) Hsp40s were able to reverse the thermosensitivity of E. coli OD259. In all cases, modified derivatives of these chimeric proteins containing an His to Gln substitution in the HPD motif of the J-domain were unable to reverse the thermosensitivity of E. coli OD259. This suggested that these J-domains exerted their in vivo functionality through a specific interaction with E. coli Hsp70, DnaK. Interestingly, a Hsp40 chimera containing the J-domain of ERj1, an integral membrane-bound ER Hsp40, was unable to reverse the thermosensitivity of E. coli OD259, suggesting that this J-domain was unable to functionally interact with DnaK. Substitutions of conserved amino acid residues and motifs were made in all four helices (I-IV) and the loop regions of the J-domains, and the modified chimeric Hsp40s were tested for functionality using the in vivo assay. Substitution of a highly conserved basic residue in helix II of the J-domain was found to disrupt in vivo functionality for all the J-domains tested. We propose that helix II and the HPD motif of the J-domain represent the fundamental elements of a binding surface required for the interaction of Hsp40s with Hsp70s, and that this surface has been conserved in mammalian, parasitic and bacterial systems.
- Full Text:
- Date Issued: 2007
Effects of substituents on the photochemical and photophysical properties of main group metal phthalocyanines
- Authors: Nyokong, Tebello
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6581 , http://hdl.handle.net/10962/d1004146
- Description: The review focuses on the photochemical (singlet oxygen and photobleaching quantum yields) and photophysical (triplet quantum yields and lifetimes and fluorescence lifetimes) properties of metallophthalocyanine complexes containing main group metals (Zn, Al, Ge, Si, Sn, Ga and In) and some unmetallated phthalocyanine complexes. Five tables containing photophysical and photochemical data for sulfonated phthalocyanines, tetra-, octa-substituted and unsubstituted phthalocyanines in a variety of solvents, are included in the review.
- Full Text:
- Date Issued: 2007
- Authors: Nyokong, Tebello
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6581 , http://hdl.handle.net/10962/d1004146
- Description: The review focuses on the photochemical (singlet oxygen and photobleaching quantum yields) and photophysical (triplet quantum yields and lifetimes and fluorescence lifetimes) properties of metallophthalocyanine complexes containing main group metals (Zn, Al, Ge, Si, Sn, Ga and In) and some unmetallated phthalocyanine complexes. Five tables containing photophysical and photochemical data for sulfonated phthalocyanines, tetra-, octa-substituted and unsubstituted phthalocyanines in a variety of solvents, are included in the review.
- Full Text:
- Date Issued: 2007
Development of a regional GPS-based ionospheric TEC model for South Africa
- Opperman, Ben D L, Cilliers, Pierre J, McKinnell, Lee-Anne, Haggard, Raymond
- Authors: Opperman, Ben D L , Cilliers, Pierre J , McKinnell, Lee-Anne , Haggard, Raymond
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6799 , http://hdl.handle.net/10962/d1003925
- Description: Advances in South African space physics research and related disciplines require better spatial and time resolution ionospheric information than was previously possible with the existing ionosonde network. A GPS-based, variable degree adjusted spherical harmonic (ASHA) model was developed for near real-time regional ionospheric total electron content (TEC) mapping over South Africa. Slant TEC values along oblique GPS signal paths are quantified from a network of GPS receivers and converted to vertical TEC by means of the single layer mapping function. The ASHA model coefficients and GPS differential biases are estimated from vertical TEC at the ionospheric pierce points and used to interpolate TEC at any location within the region of interest. Diurnal TEC variations with one minute time resolution and time-varying 2D regional TEC maps are constructed. In order to validate the ASHA method, simulations with an IRI ionosphere were performed, while the ASHA results from actual data were compared with two independent GPS-based methodologies and measured ionosonde data.
- Full Text:
- Date Issued: 2007
- Authors: Opperman, Ben D L , Cilliers, Pierre J , McKinnell, Lee-Anne , Haggard, Raymond
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6799 , http://hdl.handle.net/10962/d1003925
- Description: Advances in South African space physics research and related disciplines require better spatial and time resolution ionospheric information than was previously possible with the existing ionosonde network. A GPS-based, variable degree adjusted spherical harmonic (ASHA) model was developed for near real-time regional ionospheric total electron content (TEC) mapping over South Africa. Slant TEC values along oblique GPS signal paths are quantified from a network of GPS receivers and converted to vertical TEC by means of the single layer mapping function. The ASHA model coefficients and GPS differential biases are estimated from vertical TEC at the ionospheric pierce points and used to interpolate TEC at any location within the region of interest. Diurnal TEC variations with one minute time resolution and time-varying 2D regional TEC maps are constructed. In order to validate the ASHA method, simulations with an IRI ionosphere were performed, while the ASHA results from actual data were compared with two independent GPS-based methodologies and measured ionosonde data.
- Full Text:
- Date Issued: 2007
Neural network-based prediction techniques for global modeling of M(3000)F2 ionospheric parameter
- Oyeyemi, E O, McKinnell, Lee-Anne, Poole, Allon W V
- Authors: Oyeyemi, E O , McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6803 , http://hdl.handle.net/10962/d1004166
- Description: In recent times neural networks (NNs) have been employed to solve many problems in ionospheric predictions. This paper illustrates a new application of NNs in developing a global model of the ionospheric propagation factor M(3000)F2. NNs were trained with daily hourly values of M(3000)F2 from various ionospheric stations spanning the period 1964–1986 with the following temporal and spatial input parameters: Universal Time, geographic latitude, magnetic inclination, magnetic declination, solar zenith angle, day of the year, A16 index (a 2-day running mean of the 3-h planetary magnetic ap index), R2 index (a 2-month running mean of sunspot number), and the angle of meridian relative to the subsolar point. The performance of the NNs was verified by comparing the predicted values of M(3000)F2 with observed values from a few selected ionospheric stations and the IRI (International Reference Ionosphere) model (CCIR M(3000)F2 model) predicted values. The results obtained compared favourably with the IRI model. Based on the error differences, the result obtained justifies the potential of the NN technique for the predictions of M(3000)F2 values on a global scale.
- Full Text:
- Date Issued: 2007
- Authors: Oyeyemi, E O , McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6803 , http://hdl.handle.net/10962/d1004166
- Description: In recent times neural networks (NNs) have been employed to solve many problems in ionospheric predictions. This paper illustrates a new application of NNs in developing a global model of the ionospheric propagation factor M(3000)F2. NNs were trained with daily hourly values of M(3000)F2 from various ionospheric stations spanning the period 1964–1986 with the following temporal and spatial input parameters: Universal Time, geographic latitude, magnetic inclination, magnetic declination, solar zenith angle, day of the year, A16 index (a 2-day running mean of the 3-h planetary magnetic ap index), R2 index (a 2-month running mean of sunspot number), and the angle of meridian relative to the subsolar point. The performance of the NNs was verified by comparing the predicted values of M(3000)F2 with observed values from a few selected ionospheric stations and the IRI (International Reference Ionosphere) model (CCIR M(3000)F2 model) predicted values. The results obtained compared favourably with the IRI model. Based on the error differences, the result obtained justifies the potential of the NN technique for the predictions of M(3000)F2 values on a global scale.
- Full Text:
- Date Issued: 2007
Patterns and processes underlying evolutionary significant units in the Platypleura stridula L. species complex (Hemiptera: Cicadidae) in the Cape Floristic Region, South Africa
- Price, Benjamin W, Barker, Nigel P, Villet, Martin H
- Authors: Price, Benjamin W , Barker, Nigel P , Villet, Martin H
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6964 , http://hdl.handle.net/10962/d1012027
- Description: Cicadas have been shown to be useful organisms for examining the effects of distribution, plant association and geographical barriers on gene flow between populations. The cicadas of the Platypleura stridula species complex are restricted to the biologically diverse Cape Floristic Region (CFR) of South Africa. They are thus an excellent study group for elucidating the mechanisms by which hemipteran diversity is generated and maintained in the CFR. Phylogeographical analysis of this species complex using mitochondrial DNA Cytochrome Oxidase I (COI) and ribosomal 16S sequence data, coupled with preliminary morphological and acoustic data, resolves six clades, each of which has specific host-plant associations and distinct geographical ranges. The phylogeographical structure implies simultaneous or near-simultaneous radiation events, coupled with shifts in host-plant associations. When calibrated using published COI and 16S substitution rates typical for related insects, these lineages date back to the late Pliocene - early Pleistocene, coincident with vegetation change, altered drainage patterns and accelerated erosion in response to neotectonic crustal uplift and cyclic Pleistocene climate change, and glaciation-associated changes in climate and sea level.
- Full Text:
- Date Issued: 2007
- Authors: Price, Benjamin W , Barker, Nigel P , Villet, Martin H
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6964 , http://hdl.handle.net/10962/d1012027
- Description: Cicadas have been shown to be useful organisms for examining the effects of distribution, plant association and geographical barriers on gene flow between populations. The cicadas of the Platypleura stridula species complex are restricted to the biologically diverse Cape Floristic Region (CFR) of South Africa. They are thus an excellent study group for elucidating the mechanisms by which hemipteran diversity is generated and maintained in the CFR. Phylogeographical analysis of this species complex using mitochondrial DNA Cytochrome Oxidase I (COI) and ribosomal 16S sequence data, coupled with preliminary morphological and acoustic data, resolves six clades, each of which has specific host-plant associations and distinct geographical ranges. The phylogeographical structure implies simultaneous or near-simultaneous radiation events, coupled with shifts in host-plant associations. When calibrated using published COI and 16S substitution rates typical for related insects, these lineages date back to the late Pliocene - early Pleistocene, coincident with vegetation change, altered drainage patterns and accelerated erosion in response to neotectonic crustal uplift and cyclic Pleistocene climate change, and glaciation-associated changes in climate and sea level.
- Full Text:
- Date Issued: 2007
How entrepreneurs deal with ethical challenges : an application of the Business Ethics Synergy Star Technique
- Robinson, David A, Davidsson, Per, Van der Mescht, Hennie, Court, Philip
- Authors: Robinson, David A , Davidsson, Per , Van der Mescht, Hennie , Court, Philip
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6079 , http://hdl.handle.net/10962/d1006123
- Description: Entrepreneurs typically live with the ever present threat of business failure arising from limited financial resources and aggressive competition in the marketplace. Under these circumstances, conflicting priorities arise and the entrepreneur is thus faced with certain dilemmas. In seeking to resolve these, entrepreneurs must often rely on their own judgment to determine ‘‘what is right’’. There is thus a need for a technique to assist them decide on a course of action when no precedent or obvious solution exists. This research paper examines how entrepreneurs experience and deal with these dilemmas. The research is based on interviews with seven entrepreneurs in established service-oriented ventures, which gave rise to 26 dilemmas. These dilemmas were analyzed by making use of the Synergy Star technique, which is introduced here as a tool that is useful in defining any dilemma, isolating the ethical component, and resolving the dilemma in a way that is congruent with the entrepreneur’s personal world-view.
- Full Text:
- Date Issued: 2007
- Authors: Robinson, David A , Davidsson, Per , Van der Mescht, Hennie , Court, Philip
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6079 , http://hdl.handle.net/10962/d1006123
- Description: Entrepreneurs typically live with the ever present threat of business failure arising from limited financial resources and aggressive competition in the marketplace. Under these circumstances, conflicting priorities arise and the entrepreneur is thus faced with certain dilemmas. In seeking to resolve these, entrepreneurs must often rely on their own judgment to determine ‘‘what is right’’. There is thus a need for a technique to assist them decide on a course of action when no precedent or obvious solution exists. This research paper examines how entrepreneurs experience and deal with these dilemmas. The research is based on interviews with seven entrepreneurs in established service-oriented ventures, which gave rise to 26 dilemmas. These dilemmas were analyzed by making use of the Synergy Star technique, which is introduced here as a tool that is useful in defining any dilemma, isolating the ethical component, and resolving the dilemma in a way that is congruent with the entrepreneur’s personal world-view.
- Full Text:
- Date Issued: 2007
Xylem as well as phloem sustains severe damage due to feeding by the Russian wheat aphid
- Saheed, S A, Liu, Lin, Jonsson, L M V, Botha, Christiaan E J
- Authors: Saheed, S A , Liu, Lin , Jonsson, L M V , Botha, Christiaan E J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6541 , http://hdl.handle.net/10962/d1005983
- Description: Investigation of comparative effects of feeding damage by the Russian wheat aphid (RWA, biotype SA1, Diuraphis noxia Mordvilko) on leaf blades of susceptible and resistant wheat cultivars (Triticum aestivum L. var Betta and Betta-Dn1 respectively) were carried out to establish the level of ultrastructural damage caused by this aphid and the possible limitation of damage induced which could be ascribed to the resistance gene Dn1 over the susceptible cultivar. Ultrastructurally, Betta-Dn1 sustained less damage to the vascular tissue as well as to the mesophyll during the experimental period. Both inter- and intracellular probes resulted in considerable saliva deposition as the aphids probed for suitable feeding sites. Salivary tracks were observed between and within mesophyll, bundle sheath cells as well as the vascular tissue, including the xylem. Disruption of organelles and cytoplasm resulted from cell probing and sheath deposition. Cell and organelle damage was more evident in the non-resistant Betta cultivar. The aphids probed for and fed from thin-walled sieve tubes preferentially. Few thick-walled sieve tubes showed evidence of either aphid probing or feeding-related damage. Saliva was deposited when the aphids probed inter- and intracellularly for feeding sites. The aphids appeared preferentially to probe for and feed from thin-walled sieve tubes, as few thick-walled sieve tubes showed evidence of damage. Vessels, apparently probed for water, contained watery saliva that encased the secondary walls and sealed pit membranes between probed vessels and xylem parenchyma. The xylem probed by the RWA was rendered non-functional, probably contributing to symptoms of leaf roll, chlorosis and necrosis, which were observed within two weeks of infestation in the susceptible Betta cultivar. This damage was limited in the resistant Betta-Dn1 cultivar during the same time frame.
- Full Text:
- Date Issued: 2007
- Authors: Saheed, S A , Liu, Lin , Jonsson, L M V , Botha, Christiaan E J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6541 , http://hdl.handle.net/10962/d1005983
- Description: Investigation of comparative effects of feeding damage by the Russian wheat aphid (RWA, biotype SA1, Diuraphis noxia Mordvilko) on leaf blades of susceptible and resistant wheat cultivars (Triticum aestivum L. var Betta and Betta-Dn1 respectively) were carried out to establish the level of ultrastructural damage caused by this aphid and the possible limitation of damage induced which could be ascribed to the resistance gene Dn1 over the susceptible cultivar. Ultrastructurally, Betta-Dn1 sustained less damage to the vascular tissue as well as to the mesophyll during the experimental period. Both inter- and intracellular probes resulted in considerable saliva deposition as the aphids probed for suitable feeding sites. Salivary tracks were observed between and within mesophyll, bundle sheath cells as well as the vascular tissue, including the xylem. Disruption of organelles and cytoplasm resulted from cell probing and sheath deposition. Cell and organelle damage was more evident in the non-resistant Betta cultivar. The aphids probed for and fed from thin-walled sieve tubes preferentially. Few thick-walled sieve tubes showed evidence of either aphid probing or feeding-related damage. Saliva was deposited when the aphids probed inter- and intracellularly for feeding sites. The aphids appeared preferentially to probe for and feed from thin-walled sieve tubes, as few thick-walled sieve tubes showed evidence of damage. Vessels, apparently probed for water, contained watery saliva that encased the secondary walls and sealed pit membranes between probed vessels and xylem parenchyma. The xylem probed by the RWA was rendered non-functional, probably contributing to symptoms of leaf roll, chlorosis and necrosis, which were observed within two weeks of infestation in the susceptible Betta cultivar. This damage was limited in the resistant Betta-Dn1 cultivar during the same time frame.
- Full Text:
- Date Issued: 2007