The temporal occurrence of flesh flies (Diptera, Sarcophagidae) at carrion-baited traps in Grahamstown, South Africa
- Villet, Martin H, Clitheroe, Crystal, Williams, Kirstin A
- Authors: Villet, Martin H , Clitheroe, Crystal , Williams, Kirstin A
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59692 , vital:27639 , https://doi.org/10.3897/AfrInvertebr.58.9537
- Description: Eleven species of flesh fly were identified in a sample of 737 specimens captured during fortnightly trapping at three sites in Grahamstown, South Africa, over a year. Sarcophaga africa Wiedemann, 1824, S. inaequalis Austen, 1909, S. exuberans Pandelle, 1896 and S. tibialis Macquart, 1851 showed well-defined peaks between early October 2001 and late April 2002, and only S. africa was trapped at other times of year. These peaks occurred when average minimum and maximum ambient air temperatures were above 12°C and 22°C, respectively, and showed no obvious relationship to rainfall. There were indications of population cycles in all of these species. Sarcophaga hera Zumpt, 1972, S. arno Curran, 1934, S. inzi Curran, 1934, S. langi Curran, 1934, S. freyi Zumpt, 1953, S. nodosa Engel, 1925 and S. samia Curran, 1934 were too scarce to assess their patterns of occurrence rigorously. Insects attending a corpse are reputed to assist forensic entomologists in estimating the time of year when the body died. Some flesh flies provide more precise estimates than others, so several species should be used for cross-validation. Insect activity at a corpse depends on the weather, so that presence of a species indicates particular environmental conditions and not simply calendar dates (particularly if climate changes). Absence of a species is not necessarily evidence of specific conditions because species may not be present at all sites simultaneously, populations cycle even when their members are active, and low population densities may hamper detection of a species.
- Full Text:
- Date Issued: 2017
- Authors: Villet, Martin H , Clitheroe, Crystal , Williams, Kirstin A
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59692 , vital:27639 , https://doi.org/10.3897/AfrInvertebr.58.9537
- Description: Eleven species of flesh fly were identified in a sample of 737 specimens captured during fortnightly trapping at three sites in Grahamstown, South Africa, over a year. Sarcophaga africa Wiedemann, 1824, S. inaequalis Austen, 1909, S. exuberans Pandelle, 1896 and S. tibialis Macquart, 1851 showed well-defined peaks between early October 2001 and late April 2002, and only S. africa was trapped at other times of year. These peaks occurred when average minimum and maximum ambient air temperatures were above 12°C and 22°C, respectively, and showed no obvious relationship to rainfall. There were indications of population cycles in all of these species. Sarcophaga hera Zumpt, 1972, S. arno Curran, 1934, S. inzi Curran, 1934, S. langi Curran, 1934, S. freyi Zumpt, 1953, S. nodosa Engel, 1925 and S. samia Curran, 1934 were too scarce to assess their patterns of occurrence rigorously. Insects attending a corpse are reputed to assist forensic entomologists in estimating the time of year when the body died. Some flesh flies provide more precise estimates than others, so several species should be used for cross-validation. Insect activity at a corpse depends on the weather, so that presence of a species indicates particular environmental conditions and not simply calendar dates (particularly if climate changes). Absence of a species is not necessarily evidence of specific conditions because species may not be present at all sites simultaneously, populations cycle even when their members are active, and low population densities may hamper detection of a species.
- Full Text:
- Date Issued: 2017
The thin edge of the wedge: ukuthwala, alienation and consent
- Mwambene, Lea, Kruuse, Helen
- Authors: Mwambene, Lea , Kruuse, Helen
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129165 , vital:36226 , https://doi.org/10.1080/02587203.2017.1303902
- Description: Ukuthwala, a mock abduction of a girl for the purpose of a customary marriage, has been subject to debate at both local and national level. This debate culminated into a South African Law Reform Commission Report on the practice of ukuthwala. However, the case of Jezile v S brings theory into reality, putting in stark relief the issues that surround this custom in a constitutional democracy. The Jezile case highlights the disjuncture between communities’ lived realities and the constitutional imperatives of the right to practice one’s culture, as well as the rights to equality and dignity, specifically for women and the girl child in the context of ukuthwala. Based on field research conducted in September 2015 and April 2016 in Engcobo (where the ukuthwala was alleged to take place in Jezile), this article sets out the community’s views in the aftermath of the case. Highlighting the alienation of the community from the law, and the complexities in understanding consent, the article posits that much more needs to be done from the ‘bottom up’ to ensure gender equality and protection of the girl child from harm.
- Full Text:
- Date Issued: 2017
- Authors: Mwambene, Lea , Kruuse, Helen
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129165 , vital:36226 , https://doi.org/10.1080/02587203.2017.1303902
- Description: Ukuthwala, a mock abduction of a girl for the purpose of a customary marriage, has been subject to debate at both local and national level. This debate culminated into a South African Law Reform Commission Report on the practice of ukuthwala. However, the case of Jezile v S brings theory into reality, putting in stark relief the issues that surround this custom in a constitutional democracy. The Jezile case highlights the disjuncture between communities’ lived realities and the constitutional imperatives of the right to practice one’s culture, as well as the rights to equality and dignity, specifically for women and the girl child in the context of ukuthwala. Based on field research conducted in September 2015 and April 2016 in Engcobo (where the ukuthwala was alleged to take place in Jezile), this article sets out the community’s views in the aftermath of the case. Highlighting the alienation of the community from the law, and the complexities in understanding consent, the article posits that much more needs to be done from the ‘bottom up’ to ensure gender equality and protection of the girl child from harm.
- Full Text:
- Date Issued: 2017
The Uptake of Education for Sustainable Development in Geography Curricula in South African Secondary Schools
- Authors: Dube, Carolina
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436319 , vital:73257 , ISBN 978-3-319-45989-9 , https://doi.org/10.1007/978-3-319-45989-9_7
- Description: Curriculum innovation that took place in the post-apartheid era in South Africa provided opportunities for integrating environ-mental concerns and sustainability issues in subjects such as geography and science at further education and training level (FET). However, evidence from my PhD study in geography education at FET level shows that there are major challenges in the implementation of education for sustainable develop-ment (ESD) in the school context. These relate, firstly, to teachers’ lack of content knowledge (CK) and pedagogical content knowledge (PCK) and, secondly, to contextual issues and structural constraints within schools. In order to overcome some of the challenges, a standards-based teacher training model is recommended to ensure the mastery of appropriate competencies for the implementation of environmental educa-tion (EE) and ESD.
- Full Text:
- Date Issued: 2017
- Authors: Dube, Carolina
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436319 , vital:73257 , ISBN 978-3-319-45989-9 , https://doi.org/10.1007/978-3-319-45989-9_7
- Description: Curriculum innovation that took place in the post-apartheid era in South Africa provided opportunities for integrating environ-mental concerns and sustainability issues in subjects such as geography and science at further education and training level (FET). However, evidence from my PhD study in geography education at FET level shows that there are major challenges in the implementation of education for sustainable develop-ment (ESD) in the school context. These relate, firstly, to teachers’ lack of content knowledge (CK) and pedagogical content knowledge (PCK) and, secondly, to contextual issues and structural constraints within schools. In order to overcome some of the challenges, a standards-based teacher training model is recommended to ensure the mastery of appropriate competencies for the implementation of environmental educa-tion (EE) and ESD.
- Full Text:
- Date Issued: 2017
The use of experimental design for the development of a capillary zone electrophoresis method for the quantitation of captopril
- Mukozhiwa, S Y, Khamanga, Sandile M, Walker, Roderick B
- Authors: Mukozhiwa, S Y , Khamanga, Sandile M , Walker, Roderick B
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183828 , vital:44073 , xlink:href="https://doi.org/10.1691/ph.2017.7071"
- Description: A capillary zone electrophoresis (CZE) method for the quantitation of captopril (CPT) using UV detection was developed. Influence of electrolyte concentration and system variables on electrophoretic separation was evaluated and a central composite design (CCD) was used to optimize the method. Variables investigated were pH, molarity, applied voltage and capillary length. The influence of sodium metabisulphite on the stability of test solutions was also investigated. The use of sodium metabisulphite prevented degradation of CPT over 24 hours. A fused uncoated silica capillary of 67.5cm total and 57.5 cm effective length was used for analysis. The applied voltage and capillary length affected the migration time of CPT significantly. A 20 mM phosphate buffer adjusted to pH 7.0 was used as running buffer and an applied voltage of 23.90 kV was suitable to effect a separation. The optimized electrophoretic conditions produced sharp, well-resolved peaks for CPT and sodium metabisulphite. Linear regression analysis of the response for CPT standards revealed the method was linear (R2 = 0.9995) over the range 5-70 μg/mL. The limits of quantitation and detection were 5 and 1.5 μg/mL. A simple, rapid and reliable CZE method has been developed and successfully applied to the analysis of commercially available CPT products.
- Full Text:
- Date Issued: 2017
- Authors: Mukozhiwa, S Y , Khamanga, Sandile M , Walker, Roderick B
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183828 , vital:44073 , xlink:href="https://doi.org/10.1691/ph.2017.7071"
- Description: A capillary zone electrophoresis (CZE) method for the quantitation of captopril (CPT) using UV detection was developed. Influence of electrolyte concentration and system variables on electrophoretic separation was evaluated and a central composite design (CCD) was used to optimize the method. Variables investigated were pH, molarity, applied voltage and capillary length. The influence of sodium metabisulphite on the stability of test solutions was also investigated. The use of sodium metabisulphite prevented degradation of CPT over 24 hours. A fused uncoated silica capillary of 67.5cm total and 57.5 cm effective length was used for analysis. The applied voltage and capillary length affected the migration time of CPT significantly. A 20 mM phosphate buffer adjusted to pH 7.0 was used as running buffer and an applied voltage of 23.90 kV was suitable to effect a separation. The optimized electrophoretic conditions produced sharp, well-resolved peaks for CPT and sodium metabisulphite. Linear regression analysis of the response for CPT standards revealed the method was linear (R2 = 0.9995) over the range 5-70 μg/mL. The limits of quantitation and detection were 5 and 1.5 μg/mL. A simple, rapid and reliable CZE method has been developed and successfully applied to the analysis of commercially available CPT products.
- Full Text:
- Date Issued: 2017
The ‘decolonial turn’: what does it mean for academic staff development?
- Vorster, Jo-Anne, Quinn, Lynn
- Authors: Vorster, Jo-Anne , Quinn, Lynn
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66612 , vital:28971 , https://doi.org/10.17159/1947-9417/2017/853
- Description: publisher version , It has become increasingly evident that the discourse of transformation that has shaped the democratising of higher education institutions over the first two decades of the democratic dispensation in South Africa has now run its course. Over the past few years, and particularly during the tumultuous student protests of 2015 and 2016, students and some academics have been calling for the decolonisation of university structures and cultures, including curricula. Using concepts from Margaret Archer’s social realism we consider the failure of the discourse of transformation to lead to real change and examine a constellation of new discourses related to the decolonisation of universities that have emerged in South Africa recently. Furthermore, we critique the discourses that have underpinned our own practices as academic developers over the past two decades and then explore the implications of what could be termed a ‘decolonial turn’ 1 for academic developers and by implication for the academics with whom they work.
- Full Text:
- Date Issued: 2017
- Authors: Vorster, Jo-Anne , Quinn, Lynn
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66612 , vital:28971 , https://doi.org/10.17159/1947-9417/2017/853
- Description: publisher version , It has become increasingly evident that the discourse of transformation that has shaped the democratising of higher education institutions over the first two decades of the democratic dispensation in South Africa has now run its course. Over the past few years, and particularly during the tumultuous student protests of 2015 and 2016, students and some academics have been calling for the decolonisation of university structures and cultures, including curricula. Using concepts from Margaret Archer’s social realism we consider the failure of the discourse of transformation to lead to real change and examine a constellation of new discourses related to the decolonisation of universities that have emerged in South Africa recently. Furthermore, we critique the discourses that have underpinned our own practices as academic developers over the past two decades and then explore the implications of what could be termed a ‘decolonial turn’ 1 for academic developers and by implication for the academics with whom they work.
- Full Text:
- Date Issued: 2017
Thermally-assisted optically stimulated luminescence from deep electron traps in α-Al2O3: C, Mg
- Kalita, Jitumani M, Chithambo, Makaiko L, Polymeris, G S
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L , Polymeris, G S
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/116133 , vital:34322 , https://doi.org/10.1016/j.nimb.2017.04.075
- Description: We report thermally-assisted optically stimulated luminescence (TA-OSL) in α-Al2O3:C,Mg. The OSL was measured at elevated temperatures between 50 and 240 °C from a sample preheated to 500 °C after irradiation to 100 Gy. That OSL could be measured even after the preheating is direct evidence of the existence of deep electron traps in α-Al2O3:C,Mg. The TA-OSL intensity goes through a peak with measurement temperature. The initial increase is ascribed to thermal assistance to optical stimulation whereas the subsequent decrease in intensity is deduced to reflect increasing incidences of non-radiative recombination, that is, thermal quenching. The activation energy for thermal assistance corresponding to a deep electron trap was estimated as 0.667 ± 0.006 eV whereas the activation energy for thermal quenching was calculated as 0.90 ± 0.04 eV. The intensity of the TA-OSL was also found to increase with irradiation dose. The dose response is sublinear from 25 to 150 Gy but saturates with further increase of dose. The TA-OSL dose response has been discussed by considering the competition for charges at the deep traps. This study incidentally shows that TA-OSL can be effectively used in dosimetry involving large doses.
- Full Text: false
- Date Issued: 2017
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L , Polymeris, G S
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/116133 , vital:34322 , https://doi.org/10.1016/j.nimb.2017.04.075
- Description: We report thermally-assisted optically stimulated luminescence (TA-OSL) in α-Al2O3:C,Mg. The OSL was measured at elevated temperatures between 50 and 240 °C from a sample preheated to 500 °C after irradiation to 100 Gy. That OSL could be measured even after the preheating is direct evidence of the existence of deep electron traps in α-Al2O3:C,Mg. The TA-OSL intensity goes through a peak with measurement temperature. The initial increase is ascribed to thermal assistance to optical stimulation whereas the subsequent decrease in intensity is deduced to reflect increasing incidences of non-radiative recombination, that is, thermal quenching. The activation energy for thermal assistance corresponding to a deep electron trap was estimated as 0.667 ± 0.006 eV whereas the activation energy for thermal quenching was calculated as 0.90 ± 0.04 eV. The intensity of the TA-OSL was also found to increase with irradiation dose. The dose response is sublinear from 25 to 150 Gy but saturates with further increase of dose. The TA-OSL dose response has been discussed by considering the competition for charges at the deep traps. This study incidentally shows that TA-OSL can be effectively used in dosimetry involving large doses.
- Full Text: false
- Date Issued: 2017
Thermoluminescence of K-Mg-Al-Zn fluorophosphate glass
- Thomas, Sunil, Chithambo, Makaiko L
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124188 , vital:35574 , https://doi.org/10.1016/j.optmat.2016.12.035
- Description: The thermoluminescence of beta irradiated K-Mg-Al-Zn fluorophosphate glass is reported. A glow-curve corresponding to 10 Gy measured at 1 °C/s shows two peaks, a weaker-intensity one at 70 °C and a more prominent one at 235 °C, the subject of this report. The main peak was observed to fade with delay between irradiation and measurement and specifically, by 11% in 15 h. Its dose response is superlinear in the dose range 1–190 Gy although the change was linear for the initial 10 Gy. Regarding kinetic analysis, the activation energy of the higher temperature peak was evaluated as 1.31 eV and that of the lower temperature peak was found as 0.47 eV. It was also noted that the main peak is affected by thermal quenching with an activation energy for thermal quenching equal to 1.37 eV. It is proposed that the mechanism associated with the thermoluminescence in K-Mg-Al-Zn fluorophosphate glass is that electrons trapped by the metal cations are released during heating and then recombine with holes at oxygen sites.
- Full Text: false
- Date Issued: 2017
- Authors: Thomas, Sunil , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124188 , vital:35574 , https://doi.org/10.1016/j.optmat.2016.12.035
- Description: The thermoluminescence of beta irradiated K-Mg-Al-Zn fluorophosphate glass is reported. A glow-curve corresponding to 10 Gy measured at 1 °C/s shows two peaks, a weaker-intensity one at 70 °C and a more prominent one at 235 °C, the subject of this report. The main peak was observed to fade with delay between irradiation and measurement and specifically, by 11% in 15 h. Its dose response is superlinear in the dose range 1–190 Gy although the change was linear for the initial 10 Gy. Regarding kinetic analysis, the activation energy of the higher temperature peak was evaluated as 1.31 eV and that of the lower temperature peak was found as 0.47 eV. It was also noted that the main peak is affected by thermal quenching with an activation energy for thermal quenching equal to 1.37 eV. It is proposed that the mechanism associated with the thermoluminescence in K-Mg-Al-Zn fluorophosphate glass is that electrons trapped by the metal cations are released during heating and then recombine with holes at oxygen sites.
- Full Text: false
- Date Issued: 2017
Thermoluminescence of SrAl2O4: Eu2+, Dy3+: kinetic analysis of a composite-peak
- Chithambo, Makaiko L, Wako, A H, Finch, A A
- Authors: Chithambo, Makaiko L , Wako, A H , Finch, A A
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124157 , vital:35571 , https://doi.org/10.1016/j.radmeas.2016.12.009
- Description: The kinetic analysis of thermoluminescence of beta-irradiated SrAl2O4:Eu2+,Dy3+ is reported. The glow-curve is dominated by an apparently-single peak. It has been demonstrated using a number of tests including partial dynamic-heating, isothermal heating, phosphorescence and, the effect of fading, that the peak and the glow-curve consists of a set of closely-spaced peaks. In view of the peak being complex, its first few components were abstracted and analysed and for comparison, the peak was also analysed assuming it is genuinely single.
- Full Text: false
- Date Issued: 2017
- Authors: Chithambo, Makaiko L , Wako, A H , Finch, A A
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124157 , vital:35571 , https://doi.org/10.1016/j.radmeas.2016.12.009
- Description: The kinetic analysis of thermoluminescence of beta-irradiated SrAl2O4:Eu2+,Dy3+ is reported. The glow-curve is dominated by an apparently-single peak. It has been demonstrated using a number of tests including partial dynamic-heating, isothermal heating, phosphorescence and, the effect of fading, that the peak and the glow-curve consists of a set of closely-spaced peaks. In view of the peak being complex, its first few components were abstracted and analysed and for comparison, the peak was also analysed assuming it is genuinely single.
- Full Text: false
- Date Issued: 2017
Thermoluminescence of the main peak in SrAl2O4: Eu2+, Dy3+: spectral and kinetics features of secondary emission detected in the ultra-violet region
- Authors: Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124197 , vital:35575 , https://doi.org/10.1016/j.radmeas.2016.12.001
- Description: We report the thermoluminescence of SrAl2O4:Eu2+,Dy3+ measured in the ultra-violet region of the spectrum between 300 and 400 nm. Complementary measurements of X-ray excited optical luminescence confirm emission bands of stimulated luminescence in this region. As a further test, optically stimulated luminescence was also measured in this region. The glow curve measured at 1 °C s−1 following irradiation to various doses appears simple and single but is in reality a collection of several components. This was shown by results from the Tm-Tstop method on both ends of the peak, application of thermal cleaning beyond the peak maximum as well as the dependence of the peak on fading. The latter shows that new peaks appear as preceding ones fade. Kinetic analysis of some of the main peaks was carried out giving an activation energy of 0.6 eV. The implication of the results on measurement of phosphorescence, interpretation of dose response and fading is discussed.
- Full Text: false
- Date Issued: 2017
- Authors: Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124197 , vital:35575 , https://doi.org/10.1016/j.radmeas.2016.12.001
- Description: We report the thermoluminescence of SrAl2O4:Eu2+,Dy3+ measured in the ultra-violet region of the spectrum between 300 and 400 nm. Complementary measurements of X-ray excited optical luminescence confirm emission bands of stimulated luminescence in this region. As a further test, optically stimulated luminescence was also measured in this region. The glow curve measured at 1 °C s−1 following irradiation to various doses appears simple and single but is in reality a collection of several components. This was shown by results from the Tm-Tstop method on both ends of the peak, application of thermal cleaning beyond the peak maximum as well as the dependence of the peak on fading. The latter shows that new peaks appear as preceding ones fade. Kinetic analysis of some of the main peaks was carried out giving an activation energy of 0.6 eV. The implication of the results on measurement of phosphorescence, interpretation of dose response and fading is discussed.
- Full Text: false
- Date Issued: 2017
Thermoluminescence of α-Al2O3: C, Mg: kinetic analysis of the main glow peak
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119844 , vital:34788 , https://doi.org/10.1016/j.jlumin.2016.10.031
- Description: The kinetic analysis of the thermoluminescence of aluminium oxide doped with carbon and co-doped with magnesium (α-Al2O3:C,Mg) is reported. Measurements were made at 1 °C/s following beta irradiation to 1 Gy. The glow curve consists of a dominant peak at a peak-maximum Tm of 161 °C and six secondary peaks of weaker intensity at 42, 72, 193, 279, 330 and 370 °C. Kinetic analysis of the main peak, the subject of this report, was carried out using initial rise, whole glow peak, peak shape, curve fitting and variable heating rate methods. The order of kinetics of the main peak was determined as first order using various methods including the Tm–Tstop technique and the dependence of Tm on irradiation dose. The activation energy of the peak is about ~1.36 eV and the frequency factor of the order of 1014 s−1. The peak area changes with heating rate in a manner that shows that the peak is affected by thermal quenching. The activation energy of thermal quenching was evaluated as 0.99±0.08 eV. A comparison of analytical results from the main peak before and after correction for thermal quenching show that the kinetic parameters of the main peak are not that affected by thermal quenching.
- Full Text: false
- Date Issued: 2017
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/119844 , vital:34788 , https://doi.org/10.1016/j.jlumin.2016.10.031
- Description: The kinetic analysis of the thermoluminescence of aluminium oxide doped with carbon and co-doped with magnesium (α-Al2O3:C,Mg) is reported. Measurements were made at 1 °C/s following beta irradiation to 1 Gy. The glow curve consists of a dominant peak at a peak-maximum Tm of 161 °C and six secondary peaks of weaker intensity at 42, 72, 193, 279, 330 and 370 °C. Kinetic analysis of the main peak, the subject of this report, was carried out using initial rise, whole glow peak, peak shape, curve fitting and variable heating rate methods. The order of kinetics of the main peak was determined as first order using various methods including the Tm–Tstop technique and the dependence of Tm on irradiation dose. The activation energy of the peak is about ~1.36 eV and the frequency factor of the order of 1014 s−1. The peak area changes with heating rate in a manner that shows that the peak is affected by thermal quenching. The activation energy of thermal quenching was evaluated as 0.99±0.08 eV. A comparison of analytical results from the main peak before and after correction for thermal quenching show that the kinetic parameters of the main peak are not that affected by thermal quenching.
- Full Text: false
- Date Issued: 2017
The‘person without the person’ in the early work of Paul Emmanuel:
- Authors: Bronner, Irene
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147737 , vital:38666 , https://doi.org/10.1080/00043389.2012.11877161
- Description: Paul Emmanuel’s early prints and incised drawings represent the human body as a presence that either is not easily seen, actively disappears or erases itself, or is entirely absent. In doing so, these still life and landscape works metaphorically explore inner, psychological ‘landscapes’, both conscious and unconscious. By drawing deliberate attention to his oblique and deceptive surfaces, Emmanuel’s process, medium and subject matter may be said to express subjectivity as a process of materialisation, as formed through the contingencies and inconsistencies of vision, experience and memory. To ‘see’ this process, and to understand what Emmanuel means by ‘seeing and not seeing’, I consider two strategies that Emmanuel arguably employs to disrupt viewing: partial, fragmented and multiple perspectives and empty clothing abandoned in landscapes.
- Full Text:
- Date Issued: 2017
- Authors: Bronner, Irene
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147737 , vital:38666 , https://doi.org/10.1080/00043389.2012.11877161
- Description: Paul Emmanuel’s early prints and incised drawings represent the human body as a presence that either is not easily seen, actively disappears or erases itself, or is entirely absent. In doing so, these still life and landscape works metaphorically explore inner, psychological ‘landscapes’, both conscious and unconscious. By drawing deliberate attention to his oblique and deceptive surfaces, Emmanuel’s process, medium and subject matter may be said to express subjectivity as a process of materialisation, as formed through the contingencies and inconsistencies of vision, experience and memory. To ‘see’ this process, and to understand what Emmanuel means by ‘seeing and not seeing’, I consider two strategies that Emmanuel arguably employs to disrupt viewing: partial, fragmented and multiple perspectives and empty clothing abandoned in landscapes.
- Full Text:
- Date Issued: 2017
Tourism entrepreneurship: the contours of challenges faced by female-owned BnBs and Guesthouses in Mthatha, South Africa
- Hlanyane, Tabisa Monalisa, Acheampong, Kofi Owusu
- Authors: Hlanyane, Tabisa Monalisa , Acheampong, Kofi Owusu
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6563 , vital:46659 , https://www.ajhtl.com/uploads/7/1/6/3/7163688/article_50_vol_6__4__2017.pdf
- Description: The purpose of the study was to investigate and discover the facts about the challenges of female entrepreneurs who are the owners of bed and breakfasts and guesthouses in Mthatha, and to find out whether these challenges have an impact in their business performance. By way of using a semi-structured survey, women who own guesthouses and bed and breakfast establishments were targeted by way of a purposive snowball sampling technique. The primary data collected indicated that female-entrepreneurs in Mthatha face a number of challenges including limited access to finance, seasonality, balancing work and family life, corruption/bribery, poor infrastructure, inability to attend seminars and workshops to network, poor customer service and lack of awareness to the required training/skills to function effectively. However, such women remain resilient to the aforementioned challenges, largely motivated by such factors linked to flexibility, the quest to remain independent and the belief in the opportunity and financial incentives that their operation represents. This study has implications for entrepreneurship and economic growth in South Africa and how vulnerable businesses including women’s require continuous support from government and private sector to remain competitive and economically sustainable.ackground:Context-specific factors influence adherence to antiretroviral therapy (ART) among pregnant womenliving with HIV. Gaps exist in the understanding of the reasons for the variable outcomes of the prevention ofmother-to-child transmission (PMTCT) programme at the health facility level in South Africa. This study examinedadherence levels and reasons for non-adherence during pregnancy in a cohort of parturient women enrolled in thePMTCT programme in the Eastern Cape, South Africa.Methods:This was a mixed-methods study involving 1709 parturient women in the Eastern Cape, South Africa. Weconducted a multi-centre retrospective analysis of the mother-infant pair in the PMTCT electronic database in 2016.Semi-structured interviews of purposively selected parturient women with self-reported poor adherence (n= 177)were conducted to gain understanding of the main barriers to adherence. Binary logistic regression was used todetermine the independent predictors of ART non-adherence.Results:A high proportion (69.0%) of women reported perfect adherence. In the logistic regression analysis, afteradjusting for confounding factors, marital status, cigarette smoking, alcohol use and non-disclosure to a family memberwere the independent predictors of non-adherence. Analysis of the qualitative data revealed that drug-related side-effects, being away from home, forgetfulness, non-disclosure, stigma and work-related demand were among the mainreasons for non-adherence to ART.Conclusions:Non-adherence to the antiretroviral therapy among pregnant women in this setting is associated withlifestyle behaviours, HIV-related stigma and ART side-effects. In order to eliminate mother-to-child transmission of HIV,clinicians need to screen for these factors at every antenatal clinic visit.Keywords:Adherence, Non-adherence, HIV, Antiretroviral therapy, Elimination of mother-to-child transmission,Prevention of mother-to-child transmission, Stigma, South Africa
- Full Text:
- Date Issued: 2017
- Authors: Hlanyane, Tabisa Monalisa , Acheampong, Kofi Owusu
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6563 , vital:46659 , https://www.ajhtl.com/uploads/7/1/6/3/7163688/article_50_vol_6__4__2017.pdf
- Description: The purpose of the study was to investigate and discover the facts about the challenges of female entrepreneurs who are the owners of bed and breakfasts and guesthouses in Mthatha, and to find out whether these challenges have an impact in their business performance. By way of using a semi-structured survey, women who own guesthouses and bed and breakfast establishments were targeted by way of a purposive snowball sampling technique. The primary data collected indicated that female-entrepreneurs in Mthatha face a number of challenges including limited access to finance, seasonality, balancing work and family life, corruption/bribery, poor infrastructure, inability to attend seminars and workshops to network, poor customer service and lack of awareness to the required training/skills to function effectively. However, such women remain resilient to the aforementioned challenges, largely motivated by such factors linked to flexibility, the quest to remain independent and the belief in the opportunity and financial incentives that their operation represents. This study has implications for entrepreneurship and economic growth in South Africa and how vulnerable businesses including women’s require continuous support from government and private sector to remain competitive and economically sustainable.ackground:Context-specific factors influence adherence to antiretroviral therapy (ART) among pregnant womenliving with HIV. Gaps exist in the understanding of the reasons for the variable outcomes of the prevention ofmother-to-child transmission (PMTCT) programme at the health facility level in South Africa. This study examinedadherence levels and reasons for non-adherence during pregnancy in a cohort of parturient women enrolled in thePMTCT programme in the Eastern Cape, South Africa.Methods:This was a mixed-methods study involving 1709 parturient women in the Eastern Cape, South Africa. Weconducted a multi-centre retrospective analysis of the mother-infant pair in the PMTCT electronic database in 2016.Semi-structured interviews of purposively selected parturient women with self-reported poor adherence (n= 177)were conducted to gain understanding of the main barriers to adherence. Binary logistic regression was used todetermine the independent predictors of ART non-adherence.Results:A high proportion (69.0%) of women reported perfect adherence. In the logistic regression analysis, afteradjusting for confounding factors, marital status, cigarette smoking, alcohol use and non-disclosure to a family memberwere the independent predictors of non-adherence. Analysis of the qualitative data revealed that drug-related side-effects, being away from home, forgetfulness, non-disclosure, stigma and work-related demand were among the mainreasons for non-adherence to ART.Conclusions:Non-adherence to the antiretroviral therapy among pregnant women in this setting is associated withlifestyle behaviours, HIV-related stigma and ART side-effects. In order to eliminate mother-to-child transmission of HIV,clinicians need to screen for these factors at every antenatal clinic visit.Keywords:Adherence, Non-adherence, HIV, Antiretroviral therapy, Elimination of mother-to-child transmission,Prevention of mother-to-child transmission, Stigma, South Africa
- Full Text:
- Date Issued: 2017
Towards a framework for assessing the sustainability of local economic development based on natural resources: honeybush tea in the Eastern Cape Province of South Africa
- Polak, James, Snowball, Jeanette D
- Authors: Polak, James , Snowball, Jeanette D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69201 , vital:29445 , https://doi.org/10.1080/13549839.2016.1196348
- Description: Despite the popularity of local economic development (LED) as a job creation and economic growth strategy in South Africa, many LED projects have not proved to be sustainable in the long-run, especially where human systems interact with biological ones. This article examines the relationship between sustainability and LED within the context of the emerging honeybush tea industry in the Eastern Cape. Data were gathered from provincial as well as local government policy documents and reports, and via key informant interviews. The data were analysed using Connelly’s [(2007). Mapping sustainable development as a contested concept. Local Environment, 12 (3), 259–278] three pronged approach to sustainable development as a lens through which to view the local industry. Findings showed that the industry offers many opportunities for development, including job creation in poorer, rural households; sustainable wild harvesting using a permit system; commercial cultivation; potential to develop social capital; potential for community-based LED; and product diversification. However, there are also corresponding challenges: There is currently no reliable data on the maximum sustainable yield, which is needed to guide quota allocations for entrepreneurial harvesters harvesting from wild stocks; possible biodiversity loss; and enforcing the permit scheme is proving difficult in remote rural areas.
- Full Text: false
- Date Issued: 2017
- Authors: Polak, James , Snowball, Jeanette D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69201 , vital:29445 , https://doi.org/10.1080/13549839.2016.1196348
- Description: Despite the popularity of local economic development (LED) as a job creation and economic growth strategy in South Africa, many LED projects have not proved to be sustainable in the long-run, especially where human systems interact with biological ones. This article examines the relationship between sustainability and LED within the context of the emerging honeybush tea industry in the Eastern Cape. Data were gathered from provincial as well as local government policy documents and reports, and via key informant interviews. The data were analysed using Connelly’s [(2007). Mapping sustainable development as a contested concept. Local Environment, 12 (3), 259–278] three pronged approach to sustainable development as a lens through which to view the local industry. Findings showed that the industry offers many opportunities for development, including job creation in poorer, rural households; sustainable wild harvesting using a permit system; commercial cultivation; potential to develop social capital; potential for community-based LED; and product diversification. However, there are also corresponding challenges: There is currently no reliable data on the maximum sustainable yield, which is needed to guide quota allocations for entrepreneurial harvesters harvesting from wild stocks; possible biodiversity loss; and enforcing the permit scheme is proving difficult in remote rural areas.
- Full Text: false
- Date Issued: 2017
Towards professional learning communities: A review
- Tshiningayamwe, Sirkka, Songqwaru, Zintle
- Authors: Tshiningayamwe, Sirkka , Songqwaru, Zintle
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436305 , vital:73256 , ISBN 978-3-319-45989-9 , https://doi.org/10.1007/978-3-319-45989-9_19
- Description: Professional learning communities (PLCs) have proven to be effective models of teachers’ professional development. Therefore, for effective Education for Sustainable Develop-ment (ESD), PLCs should be considered in the planning of teacher professional development initiatives. This will enable teachers to address issues of quality teaching, learning and sustainable development issues. In the South African context, a ‘professional learning community’ is an emerging policy con-cept. This chapter thus provides a review of the emergence of teacher clusters in South Africa using a reflexive spiral model and praxis tasks. The chapter also draws from the Namibian and South African teacher cluster literature to comment on how teacher clusters could potentially be translated into PLCs to transform teachers’ practices as they relate to ESD.
- Full Text:
- Date Issued: 2017
- Authors: Tshiningayamwe, Sirkka , Songqwaru, Zintle
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436305 , vital:73256 , ISBN 978-3-319-45989-9 , https://doi.org/10.1007/978-3-319-45989-9_19
- Description: Professional learning communities (PLCs) have proven to be effective models of teachers’ professional development. Therefore, for effective Education for Sustainable Develop-ment (ESD), PLCs should be considered in the planning of teacher professional development initiatives. This will enable teachers to address issues of quality teaching, learning and sustainable development issues. In the South African context, a ‘professional learning community’ is an emerging policy con-cept. This chapter thus provides a review of the emergence of teacher clusters in South Africa using a reflexive spiral model and praxis tasks. The chapter also draws from the Namibian and South African teacher cluster literature to comment on how teacher clusters could potentially be translated into PLCs to transform teachers’ practices as they relate to ESD.
- Full Text:
- Date Issued: 2017
Tracks and Traces: Andrew Tshabangu’s ‘Footprints’
- Authors: Lila, Philiswa
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147138 , vital:38596 , https://artthrob.co.za/2017/03/08/tracks-and-traces-andrew-tshabangus-footprints/
- Description: Andrew Tshabangu ‘Footprints’ at the Standard Bank Art Gallery is a hand-picked collection of photographs that span the past 20 years of Tshabangu’s career. Curated by Thembinkosi Goniwe, the narrative is uncomplicated and uncluttered, thus allowing the images breathing space for engagement. The display is precise with careful attention to detail, appearing neat, slick and efficient; a characteristic mirrored in Tshabangu’s photography.
- Full Text:
- Date Issued: 2017
- Authors: Lila, Philiswa
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147138 , vital:38596 , https://artthrob.co.za/2017/03/08/tracks-and-traces-andrew-tshabangus-footprints/
- Description: Andrew Tshabangu ‘Footprints’ at the Standard Bank Art Gallery is a hand-picked collection of photographs that span the past 20 years of Tshabangu’s career. Curated by Thembinkosi Goniwe, the narrative is uncomplicated and uncluttered, thus allowing the images breathing space for engagement. The display is precise with careful attention to detail, appearing neat, slick and efficient; a characteristic mirrored in Tshabangu’s photography.
- Full Text:
- Date Issued: 2017
Transgressing the norm: Transformative agency in community-based learning for sustainability in southern African contexts
- Lotz-Sisitka, Heila, Mukute, Mutizwa, Chikunda, Charles, Baloi, Aristides, Pesanayi, Tichaona V
- Authors: Lotz-Sisitka, Heila , Mukute, Mutizwa , Chikunda, Charles , Baloi, Aristides , Pesanayi, Tichaona V
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127204 , vital:35977 , https://10.1007/s11159-017-9689-3
- Description: Environment and sustainability education processes are often oriented to change and transformation, and frequently involve the emergence of new forms of human activity. However, not much is known about how such change emerges from the learning process, or how it contributes to the development of transformative agency in community contexts. The authors of this article present four cross-case perspectives of expansive learning and transformative agency development in community-based education in southern Africa, studying communities pursuing new activities that are more socially just and sustainable. The four cases of community learning and transformative agency focus on the following activities: (1) sustainable agriculture in Lesotho; (2) seed saving and rainwater harvesting in Zimbabwe; (3) community-based irrigation scheme management in Mozambique; and (4) biodiversity conservation co-management in South Africa. The case studies all draw on cultural-historical activity theory to guide learning and change processes, especially third-generation cultural-historical activity theory (CHAT), which emphasises expansive learning in collectives across interacting activity systems. CHAT researchers, such as the authors of this article, argue that expansive learning can lead to the emergence of transformative agency. The authors extend their transformative agency analysis to probe if and how expansive learning might also facilitate instances of transgressing norms – viewed here as embedded practices which need to be reframed and changed in order for sustainability to emerge.
- Full Text:
- Date Issued: 2017
- Authors: Lotz-Sisitka, Heila , Mukute, Mutizwa , Chikunda, Charles , Baloi, Aristides , Pesanayi, Tichaona V
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127204 , vital:35977 , https://10.1007/s11159-017-9689-3
- Description: Environment and sustainability education processes are often oriented to change and transformation, and frequently involve the emergence of new forms of human activity. However, not much is known about how such change emerges from the learning process, or how it contributes to the development of transformative agency in community contexts. The authors of this article present four cross-case perspectives of expansive learning and transformative agency development in community-based education in southern Africa, studying communities pursuing new activities that are more socially just and sustainable. The four cases of community learning and transformative agency focus on the following activities: (1) sustainable agriculture in Lesotho; (2) seed saving and rainwater harvesting in Zimbabwe; (3) community-based irrigation scheme management in Mozambique; and (4) biodiversity conservation co-management in South Africa. The case studies all draw on cultural-historical activity theory to guide learning and change processes, especially third-generation cultural-historical activity theory (CHAT), which emphasises expansive learning in collectives across interacting activity systems. CHAT researchers, such as the authors of this article, argue that expansive learning can lead to the emergence of transformative agency. The authors extend their transformative agency analysis to probe if and how expansive learning might also facilitate instances of transgressing norms – viewed here as embedded practices which need to be reframed and changed in order for sustainability to emerge.
- Full Text:
- Date Issued: 2017
Umzila: a mark or track made by dragging any heavy body along the ground
- Authors: Makandula, Sukhumbuzo
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146523 , vital:38533 , https://www.ug.edu.gh/events/arts-council-african-studies-association-acasa-17th-triennial-symposium-august-8-â-13-2017
- Description: ACASA facilitates communication among scholars, teachers, students, artists, museum specialists, collectors, and all others interested in the arts of Africa and the African Diaspora. Its goals are to promote greater understanding of African material and expressive culture in all its forms, and to encourage contact and collaboration with African and Diaspora artists and scholars.
- Full Text:
- Date Issued: 2017
- Authors: Makandula, Sukhumbuzo
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146523 , vital:38533 , https://www.ug.edu.gh/events/arts-council-african-studies-association-acasa-17th-triennial-symposium-august-8-â-13-2017
- Description: ACASA facilitates communication among scholars, teachers, students, artists, museum specialists, collectors, and all others interested in the arts of Africa and the African Diaspora. Its goals are to promote greater understanding of African material and expressive culture in all its forms, and to encourage contact and collaboration with African and Diaspora artists and scholars.
- Full Text:
- Date Issued: 2017
Undefined cellulase formulations hinder scientific reproducibility
- Himmel, Michael E, Abbas, Charles A, Baker, John O, Bayer, Edward A, Bomble, Yannick J, Brunecky, Roman, Chen, Xiaowen, Felby, Claus, Jeoh, Tina, Kumar, Rajeev, McCleary, Barry V, Pletschke, Brett I, Tucker, Melvin P, Wyman, Charles E, Decker, Stephen R
- Authors: Himmel, Michael E , Abbas, Charles A , Baker, John O , Bayer, Edward A , Bomble, Yannick J , Brunecky, Roman , Chen, Xiaowen , Felby, Claus , Jeoh, Tina , Kumar, Rajeev , McCleary, Barry V , Pletschke, Brett I , Tucker, Melvin P , Wyman, Charles E , Decker, Stephen R
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61402 , vital:28022 , https://doi.org/10.1186/s13068-017-0974-y
- Description: In the shadow of a burgeoning biomass-to-fuels industry, biological conversion of lignocellulose to fermentable sugars in a cost-effective manner is key to the success of second-generation and advanced biofuel production. For the effective comparison of one cellulase preparation to another, cellulase assays are typically carried out with one or more engineered cellulase formulations or natural exoproteomes of known performance serving as positive controls. When these formulations have unknown composition, as is the case with several widely used commercial products, it becomes impossible to compare or reproduce work done today to work done in the future, where, for example, such preparations may not be available. Therefore, being a critical tenet of science publishing, experimental reproducibility is endangered by the continued use of these undisclosed products. We propose the introduction of standard procedures and materials to produce specific and reproducible cellulase formulations. These formulations are to serve as yardsticks to measure improvements and performance of new cellulase formulations.
- Full Text:
- Date Issued: 2017
- Authors: Himmel, Michael E , Abbas, Charles A , Baker, John O , Bayer, Edward A , Bomble, Yannick J , Brunecky, Roman , Chen, Xiaowen , Felby, Claus , Jeoh, Tina , Kumar, Rajeev , McCleary, Barry V , Pletschke, Brett I , Tucker, Melvin P , Wyman, Charles E , Decker, Stephen R
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61402 , vital:28022 , https://doi.org/10.1186/s13068-017-0974-y
- Description: In the shadow of a burgeoning biomass-to-fuels industry, biological conversion of lignocellulose to fermentable sugars in a cost-effective manner is key to the success of second-generation and advanced biofuel production. For the effective comparison of one cellulase preparation to another, cellulase assays are typically carried out with one or more engineered cellulase formulations or natural exoproteomes of known performance serving as positive controls. When these formulations have unknown composition, as is the case with several widely used commercial products, it becomes impossible to compare or reproduce work done today to work done in the future, where, for example, such preparations may not be available. Therefore, being a critical tenet of science publishing, experimental reproducibility is endangered by the continued use of these undisclosed products. We propose the introduction of standard procedures and materials to produce specific and reproducible cellulase formulations. These formulations are to serve as yardsticks to measure improvements and performance of new cellulase formulations.
- Full Text:
- Date Issued: 2017
Understanding spatial variation in the drivers of nature-based tourism and their influence on the sustainability of private land conservation
- Baum, Julia, Cumming, Graeme S, de Vos, Alta
- Authors: Baum, Julia , Cumming, Graeme S , de Vos, Alta
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416481 , vital:71352 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.05.005"
- Description: Protected areas connect socio-economic and ecological systems through their provision of ecosystem goods and services. Analysis of ecosystem services allows the expression of ecological benefits in economic terms. However, cultural services, such as recreation opportunities, have proved difficult to quantify. An important challenge for the analysis of cultural services is to understand the geography of service provision in relation to both human and ecological system elements. We used data on visitation rates and measures of context, content, connectivity, and location for 64 private land conservation areas (PLCAs) to better understand geographic influences on cultural service provision. Visitation to PLCAs was influenced by a combination of ecological and socio-economic drivers. Variance partitioning analysis showed that ecology explained the largest proportion of overall variation in visitation rates (26%), followed by location (22%). In tests using generalized linear mixed models, individual factors that significantly explained visitation rates included the number of mammal species, the number of Big 5-species (ecological variables), the number of facilities provided (infrastructure) and average accommodation charges (affordability). Our analysis has important implications for the economic sustainability of PLCAs and more generally for understanding the relevance of spatial variation for analyses of cultural services.
- Full Text:
- Date Issued: 2017
- Authors: Baum, Julia , Cumming, Graeme S , de Vos, Alta
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416481 , vital:71352 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.05.005"
- Description: Protected areas connect socio-economic and ecological systems through their provision of ecosystem goods and services. Analysis of ecosystem services allows the expression of ecological benefits in economic terms. However, cultural services, such as recreation opportunities, have proved difficult to quantify. An important challenge for the analysis of cultural services is to understand the geography of service provision in relation to both human and ecological system elements. We used data on visitation rates and measures of context, content, connectivity, and location for 64 private land conservation areas (PLCAs) to better understand geographic influences on cultural service provision. Visitation to PLCAs was influenced by a combination of ecological and socio-economic drivers. Variance partitioning analysis showed that ecology explained the largest proportion of overall variation in visitation rates (26%), followed by location (22%). In tests using generalized linear mixed models, individual factors that significantly explained visitation rates included the number of mammal species, the number of Big 5-species (ecological variables), the number of facilities provided (infrastructure) and average accommodation charges (affordability). Our analysis has important implications for the economic sustainability of PLCAs and more generally for understanding the relevance of spatial variation for analyses of cultural services.
- Full Text:
- Date Issued: 2017
Unexpected transformations of 3-(bromoacetyl)coumarin provides new evidence for the mechanism of thiol mediated dehalogenation of α-halocarbonyls
- Magwenzi, Faith N, Khanye, Setshaba D, Veale, Clinton G L
- Authors: Magwenzi, Faith N , Khanye, Setshaba D , Veale, Clinton G L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66200 , vital:28916 , https://doi.org/10.1016/j.tetlet.2017.01.082
- Description: publisher version , The mechanism for the thiol mediated dehalogenation of α-halogenated carbonyls has remained an unresolved problem, despite its ongoing application in synthetic organic chemistry. Nakamura and co-workers first proposed that net dehalogenation occurs via sequential nucleophilic substitutions, while Israel and co-workers concluded that the rate at which dehalogenation occurred suggested that dehalogenation proceeds in a single concerted step. In this study, we investigated the debromination and nucleophilic substitution of 3-(bromoacetyl)coumarin with a variety of thiophenols, whose electron donating or withdrawing natures resulted in large variations in the degree of nucleophilic substitution and dehalogenation products, respectively. Results from these experiments, in addition to an unexpected formation of thioether containing dibenzo[b,d]pyran-6-ones from a Robinson annulation, has provided new evidence for this disputed mechanism.
- Full Text: false
- Date Issued: 2017
- Authors: Magwenzi, Faith N , Khanye, Setshaba D , Veale, Clinton G L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66200 , vital:28916 , https://doi.org/10.1016/j.tetlet.2017.01.082
- Description: publisher version , The mechanism for the thiol mediated dehalogenation of α-halogenated carbonyls has remained an unresolved problem, despite its ongoing application in synthetic organic chemistry. Nakamura and co-workers first proposed that net dehalogenation occurs via sequential nucleophilic substitutions, while Israel and co-workers concluded that the rate at which dehalogenation occurred suggested that dehalogenation proceeds in a single concerted step. In this study, we investigated the debromination and nucleophilic substitution of 3-(bromoacetyl)coumarin with a variety of thiophenols, whose electron donating or withdrawing natures resulted in large variations in the degree of nucleophilic substitution and dehalogenation products, respectively. Results from these experiments, in addition to an unexpected formation of thioether containing dibenzo[b,d]pyran-6-ones from a Robinson annulation, has provided new evidence for this disputed mechanism.
- Full Text: false
- Date Issued: 2017