Socio-spatial dynamics in the use of wild natural resources: Evidence from six rapidly growing medium-sized cities in Africa
- Schlesinger, Johannes, Drescher, Axel W, Shackleton, Charlie M
- Authors: Schlesinger, Johannes , Drescher, Axel W , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180897 , vital:43668 , xlink:href="https://doi.org/10.1016/j.apgeog.2014.11.013"
- Description: Increasing urbanisation in sub-Saharan Africa transforms spatial configurations in and around towns and cities. At the same time wild natural resources play an important role in African livelihoods. Yet, little is known about the impact of urbanisation on the socio-spatial dynamics of the use of wild natural resources. Here we examined the importance of these resources for livelihoods, differences in their use between different locations along the urban-rural continuum, and the respective temporal dynamics. A total of 1158 households were interviewed in six medium-sized cities distributed across five African countries using a standardised questionnaire supplemented by expert interviews and spatial analyses employing Geographic Information Systems. Overall, even though periurban and rural households were more likely to use wild natural resources than those in the urban areas, the use of these resources was generally high along the entire urban-rural continuum. Despite the increasing urban pressure on these resources, they remain an integral part for most households, not only for those lacking access to productive resources, but also for those with a higher standard of living. This trend was found across all study towns, despite the marked differences in their respective socio-spatial as well as environmental settings.
- Full Text:
- Date Issued: 2015
- Authors: Schlesinger, Johannes , Drescher, Axel W , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180897 , vital:43668 , xlink:href="https://doi.org/10.1016/j.apgeog.2014.11.013"
- Description: Increasing urbanisation in sub-Saharan Africa transforms spatial configurations in and around towns and cities. At the same time wild natural resources play an important role in African livelihoods. Yet, little is known about the impact of urbanisation on the socio-spatial dynamics of the use of wild natural resources. Here we examined the importance of these resources for livelihoods, differences in their use between different locations along the urban-rural continuum, and the respective temporal dynamics. A total of 1158 households were interviewed in six medium-sized cities distributed across five African countries using a standardised questionnaire supplemented by expert interviews and spatial analyses employing Geographic Information Systems. Overall, even though periurban and rural households were more likely to use wild natural resources than those in the urban areas, the use of these resources was generally high along the entire urban-rural continuum. Despite the increasing urban pressure on these resources, they remain an integral part for most households, not only for those lacking access to productive resources, but also for those with a higher standard of living. This trend was found across all study towns, despite the marked differences in their respective socio-spatial as well as environmental settings.
- Full Text:
- Date Issued: 2015
Spawning and nest guarding of the river goby (Glossogobius callidus) from the Eastern Cape province of South Africa
- Wasserman, Ryan J, Vink, Tim J F, Woodford, Darragh J, Froneman, P William
- Authors: Wasserman, Ryan J , Vink, Tim J F , Woodford, Darragh J , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68144 , vital:29203 , https://doi.org/10.1111/aje.12228
- Description: Publisher version , Introduction: The River goby, Glossogobius callidus (Smith 1937), occurs naturally in rivers and the upper reaches of estuaries along the eastern seaboard of southern Africa (Whitfield, 1998; James et al., 2007; Wasserman, Strydom & Wooldridge, 2010). This fish species is among the most abundant of fishes in many river systems of the region and is considered an important predator in these habitats, feeding on invertebrates and small fish (Whitfield, 1998; Strydom & Neira, 2006; Wasserman, 2012; Wasserman et al., 2014). Despite this, ecological information on this goby is sparse and to date, no published records on the biology of the species exist. The urgent need for such information was recently highlighted in a study that identified G. callidus as a potentially invasive species, given its ability to rapidly establish in novel environments (Woodford et al., 2013). The present study therefore endeavoured to determine the reproductive guild to which G. callidus belong and describe aspects of their spawning. This was performed by closely observing wild caught, mature G. callidus in aquaria over a 25-day period.
- Full Text: false
- Date Issued: 2015
- Authors: Wasserman, Ryan J , Vink, Tim J F , Woodford, Darragh J , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68144 , vital:29203 , https://doi.org/10.1111/aje.12228
- Description: Publisher version , Introduction: The River goby, Glossogobius callidus (Smith 1937), occurs naturally in rivers and the upper reaches of estuaries along the eastern seaboard of southern Africa (Whitfield, 1998; James et al., 2007; Wasserman, Strydom & Wooldridge, 2010). This fish species is among the most abundant of fishes in many river systems of the region and is considered an important predator in these habitats, feeding on invertebrates and small fish (Whitfield, 1998; Strydom & Neira, 2006; Wasserman, 2012; Wasserman et al., 2014). Despite this, ecological information on this goby is sparse and to date, no published records on the biology of the species exist. The urgent need for such information was recently highlighted in a study that identified G. callidus as a potentially invasive species, given its ability to rapidly establish in novel environments (Woodford et al., 2013). The present study therefore endeavoured to determine the reproductive guild to which G. callidus belong and describe aspects of their spawning. This was performed by closely observing wild caught, mature G. callidus in aquaria over a 25-day period.
- Full Text: false
- Date Issued: 2015
Specialist workforce development through mentoring: comparing collaborative programme evaluation using action research and realist evaluation
- Akhurst, Jacqueline E, Lawson, Sally
- Authors: Akhurst, Jacqueline E , Lawson, Sally
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143771 , vital:38281 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: This Workforce Innovations Programme (WIP) was for healthcare practitioners working in north east England. The innovative mentoring-focused WIP aimed to increase capacity and capability, and to improve services and outcomes for people living with long term neurological conditions. Mentors were matched with practitioners outside of their specialisms and focused on community and partnership working as alternatives to dominant modes of practice. This paper will highlight key outcomes and contextual challenges. It will explore collaborative action research for practitioner development, evidencing the participants’ learning. A medium term realist evaluation then provides data about the value of the WIP; and illustrates ways the programme worked for practitioners and people who used services, to support the drive for improved outcomes. It will compare and contrast the contributions of both forms of programme evaluation, and critique some of the discourses of workforce improvement initiatives.
- Full Text:
- Date Issued: 2015
- Authors: Akhurst, Jacqueline E , Lawson, Sally
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143771 , vital:38281 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: This Workforce Innovations Programme (WIP) was for healthcare practitioners working in north east England. The innovative mentoring-focused WIP aimed to increase capacity and capability, and to improve services and outcomes for people living with long term neurological conditions. Mentors were matched with practitioners outside of their specialisms and focused on community and partnership working as alternatives to dominant modes of practice. This paper will highlight key outcomes and contextual challenges. It will explore collaborative action research for practitioner development, evidencing the participants’ learning. A medium term realist evaluation then provides data about the value of the WIP; and illustrates ways the programme worked for practitioners and people who used services, to support the drive for improved outcomes. It will compare and contrast the contributions of both forms of programme evaluation, and critique some of the discourses of workforce improvement initiatives.
- Full Text:
- Date Issued: 2015
Specific rewards for tax compliance: responses of small business owners in Ekurhuleni, South Africa
- Bornman, Marina, Stack, Elizabeth M
- Authors: Bornman, Marina , Stack, Elizabeth M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145325 , vital:38428 , https://heinonline.org/HOL/Page?handle=hein.journals/ejotaxrs13anddiv=35andg_sent=1andcasa_token=andcollection=journals
- Description: The literature reviewed documents the positive effects of rewards in encouraging desired behaviour, but rewards may have a crowding-in effect, strengthening intrinsic motivation, or a crowding-out effect, weakening it. External interventions may therefore be perceived as supportive, fostering self-esteem and self-determination, while those perceived as controlling may have the opposite effect. A number of countries have adopted a strategy of rewarding tax compliance. The rewards range from certificates awarded to compliant taxpayers, to privilege cards providing opportunities for discounts or special treatment, to lotteries in which compliant taxpayers can participate. The reward strategies are often accompanied by publicity programmes. Two such hypothetical strategies were presented to participants in a survey conducted amongst small business owners in Ekurhuleni, South Africa, to gauge their responses.
- Full Text:
- Date Issued: 2015
- Authors: Bornman, Marina , Stack, Elizabeth M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145325 , vital:38428 , https://heinonline.org/HOL/Page?handle=hein.journals/ejotaxrs13anddiv=35andg_sent=1andcasa_token=andcollection=journals
- Description: The literature reviewed documents the positive effects of rewards in encouraging desired behaviour, but rewards may have a crowding-in effect, strengthening intrinsic motivation, or a crowding-out effect, weakening it. External interventions may therefore be perceived as supportive, fostering self-esteem and self-determination, while those perceived as controlling may have the opposite effect. A number of countries have adopted a strategy of rewarding tax compliance. The rewards range from certificates awarded to compliant taxpayers, to privilege cards providing opportunities for discounts or special treatment, to lotteries in which compliant taxpayers can participate. The reward strategies are often accompanied by publicity programmes. Two such hypothetical strategies were presented to participants in a survey conducted amongst small business owners in Ekurhuleni, South Africa, to gauge their responses.
- Full Text:
- Date Issued: 2015
Spectroscopic and nonlinear optical properties of the four positional isomers of 4α-(4-tert-butylphenoxy) phthalocyanine
- Ngubeni, Grace N, Britton, Jonathan, Mack, John, New, Edward, Hancox, Ian, Walker, Marc, Nyokong, Tebello, Jones, Tim S, Khene,Samson M
- Authors: Ngubeni, Grace N , Britton, Jonathan , Mack, John , New, Edward , Hancox, Ian , Walker, Marc , Nyokong, Tebello , Jones, Tim S , Khene,Samson M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241448 , vital:50940 , xlink:href="https://doi.org/10.1039/C5TC01601K"
- Description: The spectroscopic and nonlinear optical properties of the positional isomers of metal free 4α-(4-tert-butylphenoxy) phthalocyanine are presented. Second order nonlinear polarizability (β), imaginary hyperpolarizability (Im(γ)) and imaginary susceptibility (Im[χ(3)]) values were determined for the four positional isomers. The measured β values of the four isomers displayed the following trend, C4h (34.0 × 10−5 m MW−1) > D2h (28.8 × 10−5 m MW−1) > C2v (22.8 × 10−5 m MW−1) > Cs (13.7 × 10−5 m MW−1).
- Full Text:
- Date Issued: 2015
- Authors: Ngubeni, Grace N , Britton, Jonathan , Mack, John , New, Edward , Hancox, Ian , Walker, Marc , Nyokong, Tebello , Jones, Tim S , Khene,Samson M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241448 , vital:50940 , xlink:href="https://doi.org/10.1039/C5TC01601K"
- Description: The spectroscopic and nonlinear optical properties of the positional isomers of metal free 4α-(4-tert-butylphenoxy) phthalocyanine are presented. Second order nonlinear polarizability (β), imaginary hyperpolarizability (Im(γ)) and imaginary susceptibility (Im[χ(3)]) values were determined for the four positional isomers. The measured β values of the four isomers displayed the following trend, C4h (34.0 × 10−5 m MW−1) > D2h (28.8 × 10−5 m MW−1) > C2v (22.8 × 10−5 m MW−1) > Cs (13.7 × 10−5 m MW−1).
- Full Text:
- Date Issued: 2015
Structural and optical properties of alloyed quaternary CdSeTeS core and CdSeTeS/ZnS core–shell quantum dots
- Adegoke, Oluwasesan, Nyokong, Tebello, Forbes, Patricia B C
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193575 , vital:45349 , xlink:href="https://doi.org/10.1016/j.jallcom.2015.05.083"
- Description: Synthesis of fluorescent alloyed quantum dots (QDs) with unique optical properties suitable for a wide array of chemical, physical and biological applications is of research interest. In this work, highly luminescent and photostable alloyed quaternary CdSeTeS core QDs of two different sizes were fabricated via the organometallic hot-injection synthetic route. Characterization of the nanocrystals were performed using TEM, XRD, UV/vis and fluorescence spectrophotometric techniques. We have demonstrated in this work that the well fabricated alloyed quaternary CdSeTeS core QDs possess unique optical properties that are advantageous over conventional core/shell systems. Formation of the CdSeTeS/ZnS core/shell with the desired optical properties comes with a number of challenges, hence the advantages of the quaternary alloyed core over the core/shell QDs are (i) avoidance of the challenging process of determining the proper shell thickness which can provide the desired optical properties in the core/shell system and (ii) avoidance of the lattice-induced mismatch between the core and the shell material which can either lead to incomplete exciton confinement or dislocation at the core/shell interface.
- Full Text:
- Date Issued: 2015
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193575 , vital:45349 , xlink:href="https://doi.org/10.1016/j.jallcom.2015.05.083"
- Description: Synthesis of fluorescent alloyed quantum dots (QDs) with unique optical properties suitable for a wide array of chemical, physical and biological applications is of research interest. In this work, highly luminescent and photostable alloyed quaternary CdSeTeS core QDs of two different sizes were fabricated via the organometallic hot-injection synthetic route. Characterization of the nanocrystals were performed using TEM, XRD, UV/vis and fluorescence spectrophotometric techniques. We have demonstrated in this work that the well fabricated alloyed quaternary CdSeTeS core QDs possess unique optical properties that are advantageous over conventional core/shell systems. Formation of the CdSeTeS/ZnS core/shell with the desired optical properties comes with a number of challenges, hence the advantages of the quaternary alloyed core over the core/shell QDs are (i) avoidance of the challenging process of determining the proper shell thickness which can provide the desired optical properties in the core/shell system and (ii) avoidance of the lattice-induced mismatch between the core and the shell material which can either lead to incomplete exciton confinement or dislocation at the core/shell interface.
- Full Text:
- Date Issued: 2015
Subjective well-being in Africa
- Botha, Ferdi, Snowball, Jeanette D
- Authors: Botha, Ferdi , Snowball, Jeanette D
- Date: 2015
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61084 , vital:27946
- Description: Research on quality of life and subjective well-being (SWB) has witnessed a remarkable growth over the past four decades or so. Since Easterlin’s (1974) seminal contribution on the relationship between happiness and income, thousands of studies have followed that examine the intricacies of subjective well-being (for reviews, see Frey and Stutzer, 2002; Dolan et al., 2008; MacKerron, 2012). These studies have uncovered some very important aspects of individual well-being and have pointed to the fact that money or income is not always (as is often assumed) the most important determinant of SWB.
- Full Text:
- Date Issued: 2015
- Authors: Botha, Ferdi , Snowball, Jeanette D
- Date: 2015
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61084 , vital:27946
- Description: Research on quality of life and subjective well-being (SWB) has witnessed a remarkable growth over the past four decades or so. Since Easterlin’s (1974) seminal contribution on the relationship between happiness and income, thousands of studies have followed that examine the intricacies of subjective well-being (for reviews, see Frey and Stutzer, 2002; Dolan et al., 2008; MacKerron, 2012). These studies have uncovered some very important aspects of individual well-being and have pointed to the fact that money or income is not always (as is often assumed) the most important determinant of SWB.
- Full Text:
- Date Issued: 2015
Surface modification of silica-coated gadolinium oxide nanoparticles with zinc tetracarboxyphenoxy phthalocyanine for the photodegradation of Orange G
- Ledwaba, Mpho, Masilela, Nkosiphile, Nyokong, Tebello, Antunes, Edith M
- Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193621 , vital:45353 , xlink:href="https://doi.org/10.1016/j.molcata.2015.03.023"
- Description: Zinc tetracarboxyphenoxy phthalocyanine was covalently linked to Gd2O3 nanoparticles for the photocatalytic degradation of Orange G. Characterization of the composite was carried out using XRD, TEM, XPS, UV–vis spectroscopy and FT-IR spectroscopy. The composite showed improved photophysical properties over the phthalocyanine alone and the catalyst was found to be reusable. Analyses of the photodegradation rates of the azo dye indicated pseudo first-order kinetics.
- Full Text:
- Date Issued: 2015
- Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193621 , vital:45353 , xlink:href="https://doi.org/10.1016/j.molcata.2015.03.023"
- Description: Zinc tetracarboxyphenoxy phthalocyanine was covalently linked to Gd2O3 nanoparticles for the photocatalytic degradation of Orange G. Characterization of the composite was carried out using XRD, TEM, XPS, UV–vis spectroscopy and FT-IR spectroscopy. The composite showed improved photophysical properties over the phthalocyanine alone and the catalyst was found to be reusable. Analyses of the photodegradation rates of the azo dye indicated pseudo first-order kinetics.
- Full Text:
- Date Issued: 2015
Survival of bifidobacteria and their usefulness in faecal source tracking
- Luyt, Catherine D, Khamanga, Sandile M, Muller, Wilhelmine J, Tandlich, Roman
- Authors: Luyt, Catherine D , Khamanga, Sandile M , Muller, Wilhelmine J , Tandlich, Roman
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76117 , vital:30508 , https://doi.org/10.1515/lwr-2015-0001
- Description: Bifidobacteria have long since been recommended as indicators of human and animal pollution. Concentration ratio (tracking ratio) of the sorbitol-utilising bifidobacteria (SUB) and the total bifidobacteria (TB) can be used to distinguish between animal and human sources of faecal water contamination. The cut-off value needs to be calibrated in a given geographical area. Seven sites with permanent faecal contamination were selected in South Africa. Concentrations of SUB ranged from 10-50000 cells/100 mL, while TB ranged from 0-8000 cells/100 mL. The tracking ratio ranged from 0.10 to 6.25, but no clear cut-off value could be established. The YN-17 agar was replaced for TB with the modified Beerens medium with pH = 5.70, to suppress the growth of faecal streptococci. Tracking ratios observed are most likely the results of different survival rates of SUB and TB. Bifidobacteria die-off due to nutrients was not found to be significant using design of experiment. Thus a lack of continuous input or oxygen levels in water may be major factors. This would limit the ratios used as a faecal source tracking method.
- Full Text:
- Date Issued: 2015
- Authors: Luyt, Catherine D , Khamanga, Sandile M , Muller, Wilhelmine J , Tandlich, Roman
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76117 , vital:30508 , https://doi.org/10.1515/lwr-2015-0001
- Description: Bifidobacteria have long since been recommended as indicators of human and animal pollution. Concentration ratio (tracking ratio) of the sorbitol-utilising bifidobacteria (SUB) and the total bifidobacteria (TB) can be used to distinguish between animal and human sources of faecal water contamination. The cut-off value needs to be calibrated in a given geographical area. Seven sites with permanent faecal contamination were selected in South Africa. Concentrations of SUB ranged from 10-50000 cells/100 mL, while TB ranged from 0-8000 cells/100 mL. The tracking ratio ranged from 0.10 to 6.25, but no clear cut-off value could be established. The YN-17 agar was replaced for TB with the modified Beerens medium with pH = 5.70, to suppress the growth of faecal streptococci. Tracking ratios observed are most likely the results of different survival rates of SUB and TB. Bifidobacteria die-off due to nutrients was not found to be significant using design of experiment. Thus a lack of continuous input or oxygen levels in water may be major factors. This would limit the ratios used as a faecal source tracking method.
- Full Text:
- Date Issued: 2015
Synthesis and characterization of Na (Y, Gd) F4 upconversion nanoparticles and an investigation of their effects on the photophysical properties of an unsubstituted tetrathiophenoxy phthalocyanine
- Taylor, Jessica M, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M
- Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241437 , vital:50939 , xlink:href="https://doi.org/10.1007/s11051-015-2889-5"
- Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs.
- Full Text:
- Date Issued: 2015
- Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241437 , vital:50939 , xlink:href="https://doi.org/10.1007/s11051-015-2889-5"
- Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs.
- Full Text:
- Date Issued: 2015
Synthesis and characterization of ZnO nanoparticle synthesized by a microwave-assisted combustion method and catalytic activity for the removal of ortho-nitrophenol
- Assi, Navid, Mohammadi, Ali, Sadr Manuchehri, Q, Walker, Roderick B
- Authors: Assi, Navid , Mohammadi, Ali , Sadr Manuchehri, Q , Walker, Roderick B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183850 , vital:44075 , xlink:href="https://doi.org/10.1080/19443994.2014.891083"
- Description: ZnO nanoparticles were manufactured using microwave-assisted combustion. The structural and morphological properties of the nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Photocatalytic degradation of ortho-nitrophenol (O-NP) in aqueous solution using the synthesized nanoparticles was performed under UV–C irradiation and is reported for the first time. The effect of the initial O-NP concentration, amount of photocatalyst, pH, and salt was investigated during photodegradation. Analysis of the degraded samples using HPLC with UV detection revealed that photocatalysis in the presence of ZnO nanoparticles removed 98% of the O-NP in 5 h. In addition, the photocatalytic degradation kinetics of O-NP were studied, and the results suggest that the data are best fitted to pseudo-first-order kinetic and Langmuir–Hinshelwood models.
- Full Text:
- Date Issued: 2015
- Authors: Assi, Navid , Mohammadi, Ali , Sadr Manuchehri, Q , Walker, Roderick B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183850 , vital:44075 , xlink:href="https://doi.org/10.1080/19443994.2014.891083"
- Description: ZnO nanoparticles were manufactured using microwave-assisted combustion. The structural and morphological properties of the nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Photocatalytic degradation of ortho-nitrophenol (O-NP) in aqueous solution using the synthesized nanoparticles was performed under UV–C irradiation and is reported for the first time. The effect of the initial O-NP concentration, amount of photocatalyst, pH, and salt was investigated during photodegradation. Analysis of the degraded samples using HPLC with UV detection revealed that photocatalysis in the presence of ZnO nanoparticles removed 98% of the O-NP in 5 h. In addition, the photocatalytic degradation kinetics of O-NP were studied, and the results suggest that the data are best fitted to pseudo-first-order kinetic and Langmuir–Hinshelwood models.
- Full Text:
- Date Issued: 2015
Synthesis and Photophysical Investigation of Tetraazaporphyrin Substituted with Aggregation‐Induced Emission (AIE) Active Moieties
- Tasso, Thiago T, Furuyama, Taniyuki, Mack, John, Nyokong, Tebello, Kobayashi, Nagao
- Authors: Tasso, Thiago T , Furuyama, Taniyuki , Mack, John , Nyokong, Tebello , Kobayashi, Nagao
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193553 , vital:45346 , xlink:href="https://doi.org/10.1002/ejic.201500726"
- Description: The synthesis and characterization of free-base and ZnII tetraazaporphyrins with tetraphenylethylene (TPE) or diphenylphenanthrene (DPP) moieties that are known to be aggregation-induced emission (AIE) active is reported. The optical spectra contain the characteristic Q and B absorption bands of Gouterman's four-orbital model and a broad envelope of weaker charge-transfer bands in the 450–600 nm region. The observed fluorescence emission lies beyond 670 nm and originates exclusively from the decay of the S1 state of the macrocycle, regardless of the excitation wavelength used. Theoretical calculations provide further evidence of strong electronic communication between the peripheral TPE or DPP moieties and the central ring. The ZnII complexes were found to have relatively high singlet-oxygen quantum yields.
- Full Text:
- Date Issued: 2015
- Authors: Tasso, Thiago T , Furuyama, Taniyuki , Mack, John , Nyokong, Tebello , Kobayashi, Nagao
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193553 , vital:45346 , xlink:href="https://doi.org/10.1002/ejic.201500726"
- Description: The synthesis and characterization of free-base and ZnII tetraazaporphyrins with tetraphenylethylene (TPE) or diphenylphenanthrene (DPP) moieties that are known to be aggregation-induced emission (AIE) active is reported. The optical spectra contain the characteristic Q and B absorption bands of Gouterman's four-orbital model and a broad envelope of weaker charge-transfer bands in the 450–600 nm region. The observed fluorescence emission lies beyond 670 nm and originates exclusively from the decay of the S1 state of the macrocycle, regardless of the excitation wavelength used. Theoretical calculations provide further evidence of strong electronic communication between the peripheral TPE or DPP moieties and the central ring. The ZnII complexes were found to have relatively high singlet-oxygen quantum yields.
- Full Text:
- Date Issued: 2015
Synthesis and photophysical properties of nanocomposites of aluminum tetrasulfonated phthalocyanine covalently linked to glutathione capped CdTe/CdS/ZnS quantum dots
- Oluwole, David O, Britton, Jonathan, Mashazi, Philani N, Nyokong, Tebello
- Authors: Oluwole, David O , Britton, Jonathan , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241379 , vital:50934 , xlink:href="https://doi.org/10.1016/j.synthmet.2015.04.015"
- Description: Aluminum tetrasulfonated phthalocyanine (ClAlTSPc) was covalently linked with different sizes of glutathione capped CdTe/CdS/ZnS quantum dots (QDs). The photophysical and Förster resonance energy transfer (FRET) properties of the nanoconjugates were investigated. The CdTe/CdS/ZnS(6.3) nanocomposite showed the highest enhancement in its photophysical properties while (CdTe/CdS/ZnS(3.2) nanocomposite showed the least. Highest FRET efficiency was observed in the linked CdTe/CdS/ZnS(6.3) nanocomposites at 93%. Hence, the combination of CdTe/CdS/ZnS with ClAlTSPc exhibited excellent photophysical properties.
- Full Text:
- Date Issued: 2015
- Authors: Oluwole, David O , Britton, Jonathan , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241379 , vital:50934 , xlink:href="https://doi.org/10.1016/j.synthmet.2015.04.015"
- Description: Aluminum tetrasulfonated phthalocyanine (ClAlTSPc) was covalently linked with different sizes of glutathione capped CdTe/CdS/ZnS quantum dots (QDs). The photophysical and Förster resonance energy transfer (FRET) properties of the nanoconjugates were investigated. The CdTe/CdS/ZnS(6.3) nanocomposite showed the highest enhancement in its photophysical properties while (CdTe/CdS/ZnS(3.2) nanocomposite showed the least. Highest FRET efficiency was observed in the linked CdTe/CdS/ZnS(6.3) nanocomposites at 93%. Hence, the combination of CdTe/CdS/ZnS with ClAlTSPc exhibited excellent photophysical properties.
- Full Text:
- Date Issued: 2015
Synthesis of single-walled carbon nanotubes by the pyrolysis of a compression activated iron (II) phthalocyanine/phthalocyanine metal-free derivative/ferric acetate mixture
- Mugadza, Tawanda, Antunes, Edith M, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Antunes, Edith M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189729 , vital:44926 , xlink:href="https://doi.org/10.1007/s12039-015-0886-y"
- Description: This paper reports on the synthesis of single walled carbon nanotubes (SWCNTs) from an activated mixture of iron (II) phthalocyanine, its metal-free derivative and ferric acetate. The powdered mixture was activated by compression into a tablet by applying a force of 300 kN, followed by re-grinding into powder and heating it to high temperatures (1000°C). The activation by compression resulted in more than 50% debundling of SWCNTs as judged by transition electron microscopy. Acid functionalization of the SWCNTs was confirmed by the increase in the D:G ratio from 0.56 to 0.87 in the Raman spectra and the observation of an average of one carboxylic acid group per 13 carbon atoms from thermogravimetric analysis (TGA). TGA also showed that the initial decomposition temperatures for the activated and non-activated mixtures to be 205°C and 245°C, respectively. Hence, activation leads to the lowering of the pyrolysis temperature of the phthalocyanines. X-ray diffraction, electronic absorption and Fourier transform infrared spectra were also employed to characterize the SWCNT.
- Full Text:
- Date Issued: 2015
- Authors: Mugadza, Tawanda , Antunes, Edith M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189729 , vital:44926 , xlink:href="https://doi.org/10.1007/s12039-015-0886-y"
- Description: This paper reports on the synthesis of single walled carbon nanotubes (SWCNTs) from an activated mixture of iron (II) phthalocyanine, its metal-free derivative and ferric acetate. The powdered mixture was activated by compression into a tablet by applying a force of 300 kN, followed by re-grinding into powder and heating it to high temperatures (1000°C). The activation by compression resulted in more than 50% debundling of SWCNTs as judged by transition electron microscopy. Acid functionalization of the SWCNTs was confirmed by the increase in the D:G ratio from 0.56 to 0.87 in the Raman spectra and the observation of an average of one carboxylic acid group per 13 carbon atoms from thermogravimetric analysis (TGA). TGA also showed that the initial decomposition temperatures for the activated and non-activated mixtures to be 205°C and 245°C, respectively. Hence, activation leads to the lowering of the pyrolysis temperature of the phthalocyanines. X-ray diffraction, electronic absorption and Fourier transform infrared spectra were also employed to characterize the SWCNT.
- Full Text:
- Date Issued: 2015
Synthesis, characterization and photophysical properties of an acenaphthalene fused-ring-expanded NIR absorbing aza-BODIPY dye
- Majumdar, Poulomi, Mack, John, Nyokong, Tebello
- Authors: Majumdar, Poulomi , Mack, John , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189763 , vital:44929 , xlink:href="https://doi.org/10.1039/C5RA14916A"
- Description: The synthesis and characterization of an NIR absorbing acenaphthalene fused-ring-expanded aza-BODIPY dye are reported. In contrast with its naphtho-fused analogue, a stable complex is obtained when the corresponding phthalonitrile is used as the precursor. A comparison is made with the photophysical properties of 3,5-diphenyl-aza-dibenzoBODIPY.
- Full Text:
- Date Issued: 2015
- Authors: Majumdar, Poulomi , Mack, John , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189763 , vital:44929 , xlink:href="https://doi.org/10.1039/C5RA14916A"
- Description: The synthesis and characterization of an NIR absorbing acenaphthalene fused-ring-expanded aza-BODIPY dye are reported. In contrast with its naphtho-fused analogue, a stable complex is obtained when the corresponding phthalonitrile is used as the precursor. A comparison is made with the photophysical properties of 3,5-diphenyl-aza-dibenzoBODIPY.
- Full Text:
- Date Issued: 2015
Synthesis, photophysical and nonlinear optical behavior of neodymium based trisphthalocyanine
- Sekhosana, Kutloana E, Amuhaya, Edith, Khene, Samson M, Nyokong, Tebello
- Authors: Sekhosana, Kutloana E , Amuhaya, Edith , Khene, Samson M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241412 , vital:50937 , xlink:href="https://doi.org/10.1016/j.ica.2014.11.029"
- Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex.
- Full Text:
- Date Issued: 2015
- Authors: Sekhosana, Kutloana E , Amuhaya, Edith , Khene, Samson M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241412 , vital:50937 , xlink:href="https://doi.org/10.1016/j.ica.2014.11.029"
- Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex.
- Full Text:
- Date Issued: 2015
Synthesis, photophysics and photochemistry of phthalocyanine-ɛ-polylysine conjugates in the presence of metal nanoparticles against Staphylococcus aureus
- Nombona, Nolwazi, Antunes, Edith M, Chidawanyika, Wadzanai J U, Kleyi, Phumelele, Tshentu, Zenixole, Nyokong, Tebello
- Authors: Nombona, Nolwazi , Antunes, Edith M , Chidawanyika, Wadzanai J U , Kleyi, Phumelele , Tshentu, Zenixole , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244439 , vital:51257 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: This work reports on the photodynamic activity of Zn phthalocyanine-ɛ-polylysine conjugates in the presence of gold and silver nanoparticles (NPs) towards the inactivation of Staphylococcus aureus (S. aureus). The conjugates showed high photoinactivation with ∼6% growth at a drug dose of 3 μM and fluence of 39.6 mW/cm2 for 10 min irradiation time in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC50) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The MIC50 was lowest for the conjugate of 3 with ɛ-polylysine at concentrations of less than 0.0058 μM in the presence of AgNPs. The lethal photosensitization of microorganisms has emerged as a promising treatment since bacteria have reduced possibilities of developing resistance to photodynamic therapy.
- Full Text:
- Date Issued: 2015
- Authors: Nombona, Nolwazi , Antunes, Edith M , Chidawanyika, Wadzanai J U , Kleyi, Phumelele , Tshentu, Zenixole , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244439 , vital:51257 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: This work reports on the photodynamic activity of Zn phthalocyanine-ɛ-polylysine conjugates in the presence of gold and silver nanoparticles (NPs) towards the inactivation of Staphylococcus aureus (S. aureus). The conjugates showed high photoinactivation with ∼6% growth at a drug dose of 3 μM and fluence of 39.6 mW/cm2 for 10 min irradiation time in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC50) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The MIC50 was lowest for the conjugate of 3 with ɛ-polylysine at concentrations of less than 0.0058 μM in the presence of AgNPs. The lethal photosensitization of microorganisms has emerged as a promising treatment since bacteria have reduced possibilities of developing resistance to photodynamic therapy.
- Full Text:
- Date Issued: 2015
Teaching Mandarin in schools is another slap in the face for African languages
- Kaschula, Russell H, Nosilela, Bulelwa, Heugh, Kathleen, Hendricks, Monica, Maseko, Pamela
- Authors: Kaschula, Russell H , Nosilela, Bulelwa , Heugh, Kathleen , Hendricks, Monica , Maseko, Pamela
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67042 , vital:29023 , https://theconversation.com/teaching-mandarin-in-schools-is-another-slap-in-the-face-for-african-languages-48505
- Description: publisher version , It’s said that behind every powerful language is an army and money. Consider the case of English. In South Africa, as in its other colonies, the British arrived with the Bible in one hand and the breech-loader in the other. Behind them was the English language, military might and money. British missionaries wanted to convert Africa’s indigenous “heathens” to Christianity; to clone little English people on the continent through the medium of English. Next came the Afrikaners, descended from the Dutch. Their slaves created a “kitchen” language out of Dutch and called it Afrikaans. White Afrikaners appropriated it as their own and it became the language of apartheid. One of the tipping points of white rule was the 1976 Soweto uprising – a furious, powerful response to the news that Afrikaans would become a compulsory medium of instruction. Now there is a new potential coloniser on South Africa’s linguistic block. From 2016, Mandarin will be taught in the country’s schools as a Second Additional Language. This new government policy will see African languages bumped even further down the educational pecking order.
- Full Text: false
- Date Issued: 2015
- Authors: Kaschula, Russell H , Nosilela, Bulelwa , Heugh, Kathleen , Hendricks, Monica , Maseko, Pamela
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67042 , vital:29023 , https://theconversation.com/teaching-mandarin-in-schools-is-another-slap-in-the-face-for-african-languages-48505
- Description: publisher version , It’s said that behind every powerful language is an army and money. Consider the case of English. In South Africa, as in its other colonies, the British arrived with the Bible in one hand and the breech-loader in the other. Behind them was the English language, military might and money. British missionaries wanted to convert Africa’s indigenous “heathens” to Christianity; to clone little English people on the continent through the medium of English. Next came the Afrikaners, descended from the Dutch. Their slaves created a “kitchen” language out of Dutch and called it Afrikaans. White Afrikaners appropriated it as their own and it became the language of apartheid. One of the tipping points of white rule was the 1976 Soweto uprising – a furious, powerful response to the news that Afrikaans would become a compulsory medium of instruction. Now there is a new potential coloniser on South Africa’s linguistic block. From 2016, Mandarin will be taught in the country’s schools as a Second Additional Language. This new government policy will see African languages bumped even further down the educational pecking order.
- Full Text: false
- Date Issued: 2015
The benefits from and barriers to participation in civic environmental organisations in South Africa
- Higgins, Olivia, Shackleton, Charlie M
- Authors: Higgins, Olivia , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180813 , vital:43648 , xlink:href="https://doi.org/10.1007/s10531-015-0924-6"
- Description: With growing global public awareness of a wide range of conservation and environmental issues, environmental volunteerism is increasing. In order to attract and retain volunteers, it is useful to understand what benefits they hope for as well as the barriers that hinder their participation. Here we examine the benefits from and barriers to participation in 26 conservation and environmental civic organisations in South Africa, categorised by their primary mission as botanical, wildlife or green. Questionnaires were sent to volunteers on the mailing list of each civic organisation (and 66 responses received), supplemented with direct interviews with key staff and five focus group discussions. There were differences in the perception of benefits obtained and barriers experienced by volunteers between the three groups. Respondents from botanical and green civic organisations rated enjoyment of the task as the primary benefit, whereas the most common response amongst wildlife organisation volunteers was a higher level of life satisfaction. Lack of time was a major barrier across all groups, whilst lack of communication between organisers and volunteers was mentioned frequently by volunteers in wildlife and green organisations. The mean number of hours offered per volunteer was significantly higher amongst wildlife organisations than either botanical or green ones, but for all three, the value of volunteer contributions was, at several millions of rand annually, substantial. There was no relationship between the number of perceived benefits and the number of hours volunteered. This study indicates that motivations and barriers differ amongst volunteers, which is important to acknowledge in attracting and optimising the contributions of conservation and environmental volunteers.
- Full Text:
- Date Issued: 2015
The benefits from and barriers to participation in civic environmental organisations in South Africa
- Authors: Higgins, Olivia , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180813 , vital:43648 , xlink:href="https://doi.org/10.1007/s10531-015-0924-6"
- Description: With growing global public awareness of a wide range of conservation and environmental issues, environmental volunteerism is increasing. In order to attract and retain volunteers, it is useful to understand what benefits they hope for as well as the barriers that hinder their participation. Here we examine the benefits from and barriers to participation in 26 conservation and environmental civic organisations in South Africa, categorised by their primary mission as botanical, wildlife or green. Questionnaires were sent to volunteers on the mailing list of each civic organisation (and 66 responses received), supplemented with direct interviews with key staff and five focus group discussions. There were differences in the perception of benefits obtained and barriers experienced by volunteers between the three groups. Respondents from botanical and green civic organisations rated enjoyment of the task as the primary benefit, whereas the most common response amongst wildlife organisation volunteers was a higher level of life satisfaction. Lack of time was a major barrier across all groups, whilst lack of communication between organisers and volunteers was mentioned frequently by volunteers in wildlife and green organisations. The mean number of hours offered per volunteer was significantly higher amongst wildlife organisations than either botanical or green ones, but for all three, the value of volunteer contributions was, at several millions of rand annually, substantial. There was no relationship between the number of perceived benefits and the number of hours volunteered. This study indicates that motivations and barriers differ amongst volunteers, which is important to acknowledge in attracting and optimising the contributions of conservation and environmental volunteers.
- Full Text:
- Date Issued: 2015
The Cohen and Kuttel stories: is the place where I hang my hat still relevant to determine my residence for tax purposes?
- Arendse, Jacqueline A, Stark, Karen, Renaud, Craig
- Authors: Arendse, Jacqueline A , Stark, Karen , Renaud, Craig
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131285 , vital:36549 , DOI: 10.25159/1998-8125/5779
- Description: Determining the residence of a taxpayer is one of the most important aspects of modern tax systems. For an individual taxpayer who migrates, a common trend in the modern world, the questions are where the person is ordinarily resident and whether the place of ordinary residence can change.
- Full Text:
- Date Issued: 2015
- Authors: Arendse, Jacqueline A , Stark, Karen , Renaud, Craig
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131285 , vital:36549 , DOI: 10.25159/1998-8125/5779
- Description: Determining the residence of a taxpayer is one of the most important aspects of modern tax systems. For an individual taxpayer who migrates, a common trend in the modern world, the questions are where the person is ordinarily resident and whether the place of ordinary residence can change.
- Full Text:
- Date Issued: 2015