HOP expression is regulated by p53 and RAS and characteristic of a cancer gene signature
- Mattison, Stacey A, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Mattison, Stacey A , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66278 , vital:28928 , https://doi.org/10.1007/s12192-016-0755-8
- Description: publisher version , The Hsp70/Hsp90 organising protein (HOP) is a co-chaperone essential for client protein transfer from Hsp70 to Hsp90 within the Hsp90 chaperone machine. Although HOP is upregulated in various cancers, there is limited information from in vitro studies on how HOP expression is regulated in cancer. The main objective of this study was to identify the HOP promoter and investigate its activity in cancerous cells. Bioinformatic analysis of the -2500 to +16 bp region of the HOP gene identified a large CpG island and a range of putative cis-elements. Many of the cis-elements were potentially bound by transcription factors which are activated by oncogenic pathways. Luciferase reporter assays demonstrated that the upstream region of the HOP gene contains an active promoter in vitro. Truncation of this region suggested that the core HOP promoter region was -855 to +16 bp. HOP promoter activity was highest in Hs578T, HEK293T and SV40- transformed MEF1 cell lines which expressed mutant or inactive p53. In a mutant p53 background, expression of wild-type p53 led to a reduction in promoter activity, while inhibition of wild-type p53 in HeLa cells increased HOP promoter activity. Additionally, in Hs578T and HEK293T cell lines containing inactive p53, expression of HRAS increased HOP promoter activity. However, HRAS activation of the HOP promoter was inhibited by p53 overexpression. These findings suggest for the first time that HOP expression in cancer may be regulated by both RAS activation and p53 inhibition. Taken together, these data suggest that HOP may be part of the cancer gene signature induced by a combination of mutant p53 and mutated RAS that is associated with cellular transformation.
- Full Text: false
- Date Issued: 2018
- Authors: Mattison, Stacey A , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66278 , vital:28928 , https://doi.org/10.1007/s12192-016-0755-8
- Description: publisher version , The Hsp70/Hsp90 organising protein (HOP) is a co-chaperone essential for client protein transfer from Hsp70 to Hsp90 within the Hsp90 chaperone machine. Although HOP is upregulated in various cancers, there is limited information from in vitro studies on how HOP expression is regulated in cancer. The main objective of this study was to identify the HOP promoter and investigate its activity in cancerous cells. Bioinformatic analysis of the -2500 to +16 bp region of the HOP gene identified a large CpG island and a range of putative cis-elements. Many of the cis-elements were potentially bound by transcription factors which are activated by oncogenic pathways. Luciferase reporter assays demonstrated that the upstream region of the HOP gene contains an active promoter in vitro. Truncation of this region suggested that the core HOP promoter region was -855 to +16 bp. HOP promoter activity was highest in Hs578T, HEK293T and SV40- transformed MEF1 cell lines which expressed mutant or inactive p53. In a mutant p53 background, expression of wild-type p53 led to a reduction in promoter activity, while inhibition of wild-type p53 in HeLa cells increased HOP promoter activity. Additionally, in Hs578T and HEK293T cell lines containing inactive p53, expression of HRAS increased HOP promoter activity. However, HRAS activation of the HOP promoter was inhibited by p53 overexpression. These findings suggest for the first time that HOP expression in cancer may be regulated by both RAS activation and p53 inhibition. Taken together, these data suggest that HOP may be part of the cancer gene signature induced by a combination of mutant p53 and mutated RAS that is associated with cellular transformation.
- Full Text: false
- Date Issued: 2018
Major security incidents since 2014: an African perspective
- Van Heerden, Renier, Von Solms, Sune, Vorster, Johannes
- Authors: Van Heerden, Renier , Von Solms, Sune , Vorster, Johannes
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68291 , vital:29234 , https://ieeexplore.ieee.org/abstract/document/8417326/
- Description: Publisher version , The integration of technology in the modern society provides many benefits, but with increased connectivity comes increased risk where governments, businesses and individuals are vulnerable to a variety of cyber-attacks. Many of the large information security attacks of the last decade can be seen as an attack on 'foreign” systems or individuals when viewed from an African perspective, with no direct impact on an individual in Africa. However, information security experts in Africa states that although some of these attacks might not have had a direct impact of the African individual, but never the less should not be ignored as it does indirectly influence the African individual. The experts state that even if the individuals or businesses are not directly influenced by an attack, it should not be ignored as similar attacks might influence them in the future. They emphasise that these attacks should improve their cybersecurity awareness and behaviour, in order to prevent similar attacks from impacting them.
- Full Text: false
- Date Issued: 2018
- Authors: Van Heerden, Renier , Von Solms, Sune , Vorster, Johannes
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68291 , vital:29234 , https://ieeexplore.ieee.org/abstract/document/8417326/
- Description: Publisher version , The integration of technology in the modern society provides many benefits, but with increased connectivity comes increased risk where governments, businesses and individuals are vulnerable to a variety of cyber-attacks. Many of the large information security attacks of the last decade can be seen as an attack on 'foreign” systems or individuals when viewed from an African perspective, with no direct impact on an individual in Africa. However, information security experts in Africa states that although some of these attacks might not have had a direct impact of the African individual, but never the less should not be ignored as it does indirectly influence the African individual. The experts state that even if the individuals or businesses are not directly influenced by an attack, it should not be ignored as similar attacks might influence them in the future. They emphasise that these attacks should improve their cybersecurity awareness and behaviour, in order to prevent similar attacks from impacting them.
- Full Text: false
- Date Issued: 2018
Comprehensive kinetic analysis of thermoluminescence peaks of α-Al2O3: C, Mg
- 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/10962/116142 , vital:34323 , https://doi.org/10.1016/j.jlumin.2017.01.003
- Description: A comprehensive kinetic analysis of the glow peaks in α-Al2O3:C,Mg is reported. A thermoluminescence glow curve measured at 1 °C/s after beta irradiation to 1 Gy shows a high intensity peak hereafter referred to as the main peak at 161 °C and six lower intensity secondary peaks at 42, 72, 193, 279, 330, 370 °C respectively. For ease of reference, the secondary peaks are labelled as I, II, IV, V, VI and VII respectively and the main peak denoted peak III. Kinetic analysis of the glow peaks has been carried out using the initial rise, whole glow peak, peak shape, variable heating rate and glow curve deconvolution methods as well as by way of phosphorescence. Using Tm-Tstop, Tm-dose and phosphorescence analyses, the order of kinetics of the peaks has been evaluated as first order. Analysis by the peak shape, whole glow peak and deconvolution methods produce the same conclusion. The activation energy of peaks I through VII are calculated as ~0.83, 0.96, 1.37, 1.20, 1.15, 1.61 and 1.94 eV respectively. The frequency factors for all the peaks are of the order of 109 to 1014 s−1. The question of thermal quenching affecting the peaks was considered. The peaks III, IV and V, the only ones that could be conveniently studied in this regard, were found to be affected by thermal quenching. The activation energy for thermal quenching was calculated for peak III as 0.96±0.03 eV, for peak VI as 0.95±0.07 eV and for peak V as 1.26±0.08 eV. The thermal quenching phenomenon has been discussed with reference to F+ and F centres. An energy band model has been developed to discuss the luminescence mechanisms in α-Al2O3:C,Mg in light of finding in this work.
- 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/10962/116142 , vital:34323 , https://doi.org/10.1016/j.jlumin.2017.01.003
- Description: A comprehensive kinetic analysis of the glow peaks in α-Al2O3:C,Mg is reported. A thermoluminescence glow curve measured at 1 °C/s after beta irradiation to 1 Gy shows a high intensity peak hereafter referred to as the main peak at 161 °C and six lower intensity secondary peaks at 42, 72, 193, 279, 330, 370 °C respectively. For ease of reference, the secondary peaks are labelled as I, II, IV, V, VI and VII respectively and the main peak denoted peak III. Kinetic analysis of the glow peaks has been carried out using the initial rise, whole glow peak, peak shape, variable heating rate and glow curve deconvolution methods as well as by way of phosphorescence. Using Tm-Tstop, Tm-dose and phosphorescence analyses, the order of kinetics of the peaks has been evaluated as first order. Analysis by the peak shape, whole glow peak and deconvolution methods produce the same conclusion. The activation energy of peaks I through VII are calculated as ~0.83, 0.96, 1.37, 1.20, 1.15, 1.61 and 1.94 eV respectively. The frequency factors for all the peaks are of the order of 109 to 1014 s−1. The question of thermal quenching affecting the peaks was considered. The peaks III, IV and V, the only ones that could be conveniently studied in this regard, were found to be affected by thermal quenching. The activation energy for thermal quenching was calculated for peak III as 0.96±0.03 eV, for peak VI as 0.95±0.07 eV and for peak V as 1.26±0.08 eV. The thermal quenching phenomenon has been discussed with reference to F+ and F centres. An energy band model has been developed to discuss the luminescence mechanisms in α-Al2O3:C,Mg in light of finding in this work.
- Full Text: false
- Date Issued: 2017
Temperature-dependence of time-resolved optically stimulated luminescence and composition heterogeneity of synthetic α-Al2O3: C
- Chithambo, Makaiko L, Costin, G
- Authors: Chithambo, Makaiko L , Costin, G
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124172 , vital:35573 , https://doi.org/10.1016/j.jlumin.2016.10.038
- Description: The relationship of pulse-width, lifetime and measurement temperature in describing intensity of time-resolved luminescence optically stimulated at 470 nm from α-Al2O3:C is reported. The change of luminescence intensity with stimulation temperature is discussed in terms of the signal integrated over a complete time-resolved luminescence spectrum or in terms of ratios of the signal emitted either during or after pulsed stimulation to the total signal obtained per spectrum. The temperature-induced change in these parameters depends on whether the pulse-width is less or more than the luminescence lifetime. This is because the lifetime in α-Al2O3:C varies with measurement temperature. We have developed and applied new models to distinguish thermal assistance from different traps and to use this information as an additional means to analyse thermal quenching by using the luminescence intensity integrated from time-resolved spectra. Using a model based on use of the throughput, the activation energy for thermal assistance was determined for the shallow trap as 0.054±0.001 eV and as 0.53±0.03 eV for the main trap. The activation energy for thermal quenching was then evaluated using luminescence yield during the pulse as 1.09±0.01 eV and as 1.12±0.01 eV using the throughput after the pulse. Using the new analytical method based on integrated intensity, the activation energy for thermal quenching was found as 1.00±0.07 eV. These values are self-consistent and show that the methods for analyzing temperature-induced changes in intensity and the attendant thermal effects, such as thermal assistance can be successfully applied. We have also reported a general mathematical model that accounts for the temperature-dependence of time-resolved luminescence from α-Al2O3:C. The luminescence study was complemented by investigation of the phase and composition heterogeneity of the samples.
- Full Text: false
- Date Issued: 2017
- Authors: Chithambo, Makaiko L , Costin, G
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124172 , vital:35573 , https://doi.org/10.1016/j.jlumin.2016.10.038
- Description: The relationship of pulse-width, lifetime and measurement temperature in describing intensity of time-resolved luminescence optically stimulated at 470 nm from α-Al2O3:C is reported. The change of luminescence intensity with stimulation temperature is discussed in terms of the signal integrated over a complete time-resolved luminescence spectrum or in terms of ratios of the signal emitted either during or after pulsed stimulation to the total signal obtained per spectrum. The temperature-induced change in these parameters depends on whether the pulse-width is less or more than the luminescence lifetime. This is because the lifetime in α-Al2O3:C varies with measurement temperature. We have developed and applied new models to distinguish thermal assistance from different traps and to use this information as an additional means to analyse thermal quenching by using the luminescence intensity integrated from time-resolved spectra. Using a model based on use of the throughput, the activation energy for thermal assistance was determined for the shallow trap as 0.054±0.001 eV and as 0.53±0.03 eV for the main trap. The activation energy for thermal quenching was then evaluated using luminescence yield during the pulse as 1.09±0.01 eV and as 1.12±0.01 eV using the throughput after the pulse. Using the new analytical method based on integrated intensity, the activation energy for thermal quenching was found as 1.00±0.07 eV. These values are self-consistent and show that the methods for analyzing temperature-induced changes in intensity and the attendant thermal effects, such as thermal assistance can be successfully applied. We have also reported a general mathematical model that accounts for the temperature-dependence of time-resolved luminescence from α-Al2O3:C. The luminescence study was complemented by investigation of the phase and composition heterogeneity of the samples.
- Full Text: false
- Date Issued: 2017
Exploring the potential impacts of tourism development on social and ecological change in the Solomon Islands
- Diedrich, Amy, Aswani, Shankar
- Authors: Diedrich, Amy , Aswani, Shankar
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67335 , vital:29074 , https://doi.org/10.1007/s13280-016-0781-x
- Description: publisher version , Pacific Island communities may be vulnerable to negative impacts of economic development, which is often considered a strategy for reducing vulnerability to environmental change. Studies that evaluate potential impacts of economic development in isolated communities may be inaccurate to only focus on asking people to anticipate impacts of phenomena they have had minimal exposure to. We used an open-ended approach to evaluate how communities in the Solomon Islands perceived change, and used this information to anticipate potential impacts of the government’s plans to develop tourism. Our results showed mostly negative expectations of change, particularly socio-cultural, which was perceived as being driven by diminishing social capital, foreign influence, and economic development. Despite minimal exposure, locals supported tourism and had more positive expectations of change associated with this activity. Our findings emphasize the need for locally appropriate planning to ensure intended positive impacts of tourism and other forms of economic development.
- Full Text: false
- Date Issued: 2016
- Authors: Diedrich, Amy , Aswani, Shankar
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67335 , vital:29074 , https://doi.org/10.1007/s13280-016-0781-x
- Description: publisher version , Pacific Island communities may be vulnerable to negative impacts of economic development, which is often considered a strategy for reducing vulnerability to environmental change. Studies that evaluate potential impacts of economic development in isolated communities may be inaccurate to only focus on asking people to anticipate impacts of phenomena they have had minimal exposure to. We used an open-ended approach to evaluate how communities in the Solomon Islands perceived change, and used this information to anticipate potential impacts of the government’s plans to develop tourism. Our results showed mostly negative expectations of change, particularly socio-cultural, which was perceived as being driven by diminishing social capital, foreign influence, and economic development. Despite minimal exposure, locals supported tourism and had more positive expectations of change associated with this activity. Our findings emphasize the need for locally appropriate planning to ensure intended positive impacts of tourism and other forms of economic development.
- Full Text: false
- Date Issued: 2016
Purification and characterization of β-mannanase from Aspergillus terreus and its applicability in depolymerization of mannans and saccharification of lignocellulosic biomass
- Soni, Hemant, Rawat, Hemant Kumar, Kango, Naveen
- Authors: Soni, Hemant , Rawat, Hemant Kumar , Kango, Naveen
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66167 , vital:28912 , https://doi.org/10.1007/s13205-016-0454-2
- Description: publisher version , Aspergillus terreus FBCC 1369 was grown in solid-state culture under statistically optimized conditions. β-Mannanase was purified to apparent homogeneity by ultrafiltration, anion exchange and gel filtration chromatography. A purification factor of 10.3-fold was achieved, with the purified enzyme exhibiting specific activity of 53 U/mg protein. The purified β-mannanase was optimally active at pH 7.0 and 70 °C and displayed stability over a broad pH range of 4.0–8.0 and a 30 min half-life at 80 °C. The molecular weight of β-mannanase was calculated as ~49 kDa by SDS-PAGE. The enzyme exhibited K m and V maxvalues of 5.9 mg/ml and 39.42 µmol/ml/min, respectively. β-Mannanase activity was stimulated by β-mercaptoethanol and strongly inhibited by Hg2+. The β-Mannanase did not hydrolyze mannobiose and mannotriose, but only mannotetraose liberating mannose and mannotriose. This indicated that at least four mannose residues were required for catalytic activity. Oligosaccharide with a degree of polymerization (DP) three was the predominant product in the case of locust bean gum (16.5 %) and guar gum (15.8 %) hydrolysis. However, the enzyme liberated DP4 oligosaccharide (24 %) exclusively from konjac gum. This property can be exploited in oligosaccharides production with DP 3–4. β-Mannanase hydrolyzed pretreated lignocelluloses and liberated reducing sugars (% theoretical yield) from copra meal (30 %). This property is an important factor for the bioconversion of the biomass.
- Full Text: false
- Date Issued: 2016
- Authors: Soni, Hemant , Rawat, Hemant Kumar , Kango, Naveen
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66167 , vital:28912 , https://doi.org/10.1007/s13205-016-0454-2
- Description: publisher version , Aspergillus terreus FBCC 1369 was grown in solid-state culture under statistically optimized conditions. β-Mannanase was purified to apparent homogeneity by ultrafiltration, anion exchange and gel filtration chromatography. A purification factor of 10.3-fold was achieved, with the purified enzyme exhibiting specific activity of 53 U/mg protein. The purified β-mannanase was optimally active at pH 7.0 and 70 °C and displayed stability over a broad pH range of 4.0–8.0 and a 30 min half-life at 80 °C. The molecular weight of β-mannanase was calculated as ~49 kDa by SDS-PAGE. The enzyme exhibited K m and V maxvalues of 5.9 mg/ml and 39.42 µmol/ml/min, respectively. β-Mannanase activity was stimulated by β-mercaptoethanol and strongly inhibited by Hg2+. The β-Mannanase did not hydrolyze mannobiose and mannotriose, but only mannotetraose liberating mannose and mannotriose. This indicated that at least four mannose residues were required for catalytic activity. Oligosaccharide with a degree of polymerization (DP) three was the predominant product in the case of locust bean gum (16.5 %) and guar gum (15.8 %) hydrolysis. However, the enzyme liberated DP4 oligosaccharide (24 %) exclusively from konjac gum. This property can be exploited in oligosaccharides production with DP 3–4. β-Mannanase hydrolyzed pretreated lignocelluloses and liberated reducing sugars (% theoretical yield) from copra meal (30 %). This property is an important factor for the bioconversion of the biomass.
- Full Text: false
- Date Issued: 2016
Time-resolved luminescence from quartz: an overview of contemporary developments and applications
- Chithambo, Makaiko L, Pagonis, Vasilis, Ankjærgaard, Christina
- Authors: Chithambo, Makaiko L , Pagonis, Vasilis , Ankjærgaard, Christina
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124743 , vital:35658 , https://doi.org/10.1016/j.physb.2015.10.014
- Description: Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al2O3:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.
- Full Text: false
- Date Issued: 2016
- Authors: Chithambo, Makaiko L , Pagonis, Vasilis , Ankjærgaard, Christina
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124743 , vital:35658 , https://doi.org/10.1016/j.physb.2015.10.014
- Description: Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al2O3:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.
- Full Text: false
- Date Issued: 2016
Water footprint assessment of citrus production in South Africa: A case study of the Lower Sundays River Valley
- Munro, Samantha A, Fraser, Gavin C G, Snowball, Jeanette D, Pahlow, Markus
- Authors: Munro, Samantha A , Fraser, Gavin C G , Snowball, Jeanette D , Pahlow, Markus
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69240 , vital:29463 , https://doi.org/10.1016/j.jclepro.2016.06.142
- Description: Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary citrus production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of production across all climatic years, followed by soft citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft citrus and navels, in that they provided higher net income and more employment hours per m3 of water in comparison to other citrus crops. In an average season, lemons generated approximately 39% more income per m3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for citrus in the catchment was calculated to be 58.7 Mm3 for an average season and 89.2 Mm3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
- Full Text: false
- Date Issued: 2016
- Authors: Munro, Samantha A , Fraser, Gavin C G , Snowball, Jeanette D , Pahlow, Markus
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69240 , vital:29463 , https://doi.org/10.1016/j.jclepro.2016.06.142
- Description: Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary citrus production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of production across all climatic years, followed by soft citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft citrus and navels, in that they provided higher net income and more employment hours per m3 of water in comparison to other citrus crops. In an average season, lemons generated approximately 39% more income per m3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for citrus in the catchment was calculated to be 58.7 Mm3 for an average season and 89.2 Mm3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
- Full Text: false
- Date Issued: 2016
Hyperbenthic and pelagic predators regulate alternate key planktonic copepods in shallow temperate estuaries
- Wasserman, Ryan J, Vink, Tim J F, Kramer, Rachel, Froneman, P William
- Authors: Wasserman, Ryan J , Vink, Tim J F , Kramer, Rachel , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68224 , vital:29220 , https://doi.org/10.1071/MF13233
- Description: Publisher version , Although predation has been identified as an important community driver, the role of predator diversity in structuring estuarine zooplankton has not been assessed. As such, we investigated the effects of two different zooplanktivorous fish species on the estuarine zooplankton community during a 12-day mesocosm study. Three experimental treatments were established, whereby natural zooplankton communities were subject to either (1) no predatory pressure, (2) predation by a pelagic predator (Monodactylus falciformis) or (3) predation by a hyper-benthic predator (Glossogobius callidus). The pelagic feeding M. falciformis fed largely on the numerically dominant mid-water copepod species, Paracartia longipatella. In contrast, the hyper-benthic fish had a greater predatory impact on the less numerically dominant copepod, Pseudodiaptomus hessei, which demonstrates strong diel vertical migration. Variations in prey-population regulation are ascribed to the distinct behavioural differences of the predators, and mediated by the differences in behaviour of the copepod species.
- Full Text: false
- Date Issued: 2014
- Authors: Wasserman, Ryan J , Vink, Tim J F , Kramer, Rachel , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68224 , vital:29220 , https://doi.org/10.1071/MF13233
- Description: Publisher version , Although predation has been identified as an important community driver, the role of predator diversity in structuring estuarine zooplankton has not been assessed. As such, we investigated the effects of two different zooplanktivorous fish species on the estuarine zooplankton community during a 12-day mesocosm study. Three experimental treatments were established, whereby natural zooplankton communities were subject to either (1) no predatory pressure, (2) predation by a pelagic predator (Monodactylus falciformis) or (3) predation by a hyper-benthic predator (Glossogobius callidus). The pelagic feeding M. falciformis fed largely on the numerically dominant mid-water copepod species, Paracartia longipatella. In contrast, the hyper-benthic fish had a greater predatory impact on the less numerically dominant copepod, Pseudodiaptomus hessei, which demonstrates strong diel vertical migration. Variations in prey-population regulation are ascribed to the distinct behavioural differences of the predators, and mediated by the differences in behaviour of the copepod species.
- Full Text: false
- Date Issued: 2014
An Unprecedented 'Precedent'?: Phodiclinics (Pty) Ltd v Pinehaven Private Hospital (Pty) Ltd (594/2010)[2011] ZASCA163 (28 September 2011); 2011 4 All SA 331 (SCA)
- Authors: Glover, Graham B
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69950 , vital:29598 , https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2364288
- Description: There are some fundamental underlying requirements that need to be in place for a system of precedent to operate. Of these I wish to isolate two that are germane to this note. The first is that court decisions (especially those in which a written judgment is handed down) need to be clearly reasoned and logically articulated to be understandable, effective and to have value in a system of precedent that finds its ultimate lodestar in the rule of law. There is no constitutional or statutory requirement that a court in all cases must furnish reasons, or even written reasons, for its decision But the practice of doing so, the Constitutional Court has said, supports the rule of law, ensuring that judicial decision-making does not occur in a manner that is arbitrary, and ensures that judges may be held accountable for their decisions. The second requirement is a technical rule – the rule of majority: if the case is heard by a full bench, and where differing opinions are handed down by the judges hearing the case, the ratio decidendi can only be identified from those judges whose reasoning is in the majority.
- Full Text: false
- Date Issued: 2013
- Authors: Glover, Graham B
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69950 , vital:29598 , https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2364288
- Description: There are some fundamental underlying requirements that need to be in place for a system of precedent to operate. Of these I wish to isolate two that are germane to this note. The first is that court decisions (especially those in which a written judgment is handed down) need to be clearly reasoned and logically articulated to be understandable, effective and to have value in a system of precedent that finds its ultimate lodestar in the rule of law. There is no constitutional or statutory requirement that a court in all cases must furnish reasons, or even written reasons, for its decision But the practice of doing so, the Constitutional Court has said, supports the rule of law, ensuring that judicial decision-making does not occur in a manner that is arbitrary, and ensures that judges may be held accountable for their decisions. The second requirement is a technical rule – the rule of majority: if the case is heard by a full bench, and where differing opinions are handed down by the judges hearing the case, the ratio decidendi can only be identified from those judges whose reasoning is in the majority.
- Full Text: false
- Date Issued: 2013
Understanding student performance in a large class
- Snowball, Jeanette D, Boughey, Chrissie
- Authors: Snowball, Jeanette D , Boughey, Chrissie
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71333 , vital:29834 , https://www.tandfonline.com/doi/abs/10.1080/14703297.2012.677658
- Description: Across the world, university teachers are increasingly being required to engage with diversity in the classes they teach. Using the data from a large Economics 1 class at a South African university, this attempts to understand the effects of diversity on chances of success and how assessment can impact on this. By demonstrating how theory can be used to understand results, the paper aims to encourage university teachers to adopt proactive strategies in managing diversity, rather than simply explaining it using student characteristics.
- Full Text: false
- Date Issued: 2012
- Authors: Snowball, Jeanette D , Boughey, Chrissie
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71333 , vital:29834 , https://www.tandfonline.com/doi/abs/10.1080/14703297.2012.677658
- Description: Across the world, university teachers are increasingly being required to engage with diversity in the classes they teach. Using the data from a large Economics 1 class at a South African university, this attempts to understand the effects of diversity on chances of success and how assessment can impact on this. By demonstrating how theory can be used to understand results, the paper aims to encourage university teachers to adopt proactive strategies in managing diversity, rather than simply explaining it using student characteristics.
- Full Text: false
- Date Issued: 2012
A new species of Diplacanthus from the Late Devonian (Famennian) of South Africa
- Authors: Gess, Robert W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73873 , vital:30237 , https://doi.org/10.1016/S0753-3969(01)88002-2
- Description: An advanced diplacanthid (Climatiiformes) is described from a Famennian estuarine environment of South Africa. It is characterized by having exceptionally long thin fin spines and a deep body form. Unusual details of the fins and fin spine insertions are preserved. This is the first record of a diplacanthid from the Southern Hemisphere.
- Full Text: false
- Date Issued: 2009
- Authors: Gess, Robert W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73873 , vital:30237 , https://doi.org/10.1016/S0753-3969(01)88002-2
- Description: An advanced diplacanthid (Climatiiformes) is described from a Famennian estuarine environment of South Africa. It is characterized by having exceptionally long thin fin spines and a deep body form. Unusual details of the fins and fin spine insertions are preserved. This is the first record of a diplacanthid from the Southern Hemisphere.
- Full Text: false
- Date Issued: 2009
Asthenospheric and lithospheric sources for Mesozoic dolerites from Liberia (Africa): trace element and isotopic evidence
- Dupuy, C, Marsh, Julian S, Dostal, J, Michard, A, Testa, S
- Authors: Dupuy, C , Marsh, Julian S , Dostal, J , Michard, A , Testa, S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140422 , vital:37887 , https://doi.org/10.1016/0012-821X(88)90067-2
- Description: Combined elemental, and Sr and Nd isotopic data are presented for Mesozoic dolerite dikes of Liberia (Africa) which are related to the initial stage of opening of the Atlantic Ocean.
- Full Text: false
- Date Issued: 2002
- Authors: Dupuy, C , Marsh, Julian S , Dostal, J , Michard, A , Testa, S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140422 , vital:37887 , https://doi.org/10.1016/0012-821X(88)90067-2
- Description: Combined elemental, and Sr and Nd isotopic data are presented for Mesozoic dolerite dikes of Liberia (Africa) which are related to the initial stage of opening of the Atlantic Ocean.
- Full Text: false
- Date Issued: 2002
Geochemical constraints on coupled assimilation and fractional crystallization involving upper crustal compositions and continental tholeiitic magma
- Authors: Marsh, Julian S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140432 , vital:37888 , https://doi.org/10.1016/0012-821X(89)90021-6
- Description: The commonly analyzed trace elements in tholeiites can be subdivided into three groups depending on their sense of enrichment or depletion in upper continental crust in relation to fractional crystallization. Lithophile incompatible elements are enriched in crustal rocks and by fractional crystallization, whereas compatible transition elements such as Ni and Cr are depleted. A small third group comprising Ti, V, Fe, and sometimes P, enrich with crystallization but are depleted in the crust.
- Full Text: false
- Date Issued: 2002
- Authors: Marsh, Julian S
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140432 , vital:37888 , https://doi.org/10.1016/0012-821X(89)90021-6
- Description: The commonly analyzed trace elements in tholeiites can be subdivided into three groups depending on their sense of enrichment or depletion in upper continental crust in relation to fractional crystallization. Lithophile incompatible elements are enriched in crustal rocks and by fractional crystallization, whereas compatible transition elements such as Ni and Cr are depleted. A small third group comprising Ti, V, Fe, and sometimes P, enrich with crystallization but are depleted in the crust.
- Full Text: false
- Date Issued: 2002
Late Devonian charophytes from the Witteberg Group, South Africa
- Gess, Robert W, Hiller, Norton
- Authors: Gess, Robert W , Hiller, Norton
- Date: 1995
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72742 , vital:30106 , https://doi.org/10.1016/0034-6667(95)00007-8
- Description: The first record of Palaeozoic charophytes from southern Africa allows the establishment of two new genera to which are assigned four new species, Octochara crassa, O. gracilis. Hexachara setacea, and H. riniensis. Each species is represented by both vegetative and reproductive structures and suggested reconstructions are presented. Associated plant and animal remains, and the sedimentology and geochemistry of the containing rocks indicate that the charophytes probably grew in the shallow parts of a brackish coastal lagoon.
- Full Text: false
- Date Issued: 1995
- Authors: Gess, Robert W , Hiller, Norton
- Date: 1995
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72742 , vital:30106 , https://doi.org/10.1016/0034-6667(95)00007-8
- Description: The first record of Palaeozoic charophytes from southern Africa allows the establishment of two new genera to which are assigned four new species, Octochara crassa, O. gracilis. Hexachara setacea, and H. riniensis. Each species is represented by both vegetative and reproductive structures and suggested reconstructions are presented. Associated plant and animal remains, and the sedimentology and geochemistry of the containing rocks indicate that the charophytes probably grew in the shallow parts of a brackish coastal lagoon.
- Full Text: false
- Date Issued: 1995
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