Biogeographical comparison of the emergent macrophyte, Sagittaria platyphylla in its native and introduced ranges
- Kwong, Raelene M, Sagliocco, Jean L, Harms, Nathan E, Butler, Kym L, Green, Peter T, Martin, Grant D
- Authors: Kwong, Raelene M , Sagliocco, Jean L , Harms, Nathan E , Butler, Kym L , Green, Peter T , Martin, Grant D
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419287 , vital:71631 , xlink:href="https://doi.org/10.1016/j.aquabot.2017.05.001"
- Description: Understanding why some plant species become invasive is important to predict and prevent future weed threats and identify appropriate management strategies. Many hypotheses have been proposed to explain why plants become invasive, yet few studies have quantitatively compared plant and population parameters between native and introduced range populations to gain an objective perspective on the causes of plant invasion. The present study uses a biogeographical field survey to compare morphological and reproductive traits and abundance between the native range (USA) and two introduced ranges (Australia and South Africa) of Sagittaria platyphylla (Engelm.) J.G. Sm (Alismataceae), a highly invasive freshwater macrophyte. Introduced and native populations differed in sexual reproductive output with the number of achenes per fruiting head and individual achene weight found to be 40% and 50% greater in introduced populations respectively. However, no other morphological traits were found to be consistently different between the native and both introduced ranges, especially after taking into account differences in environmental conditions between the three ranges. Although populations in introduced regions were larger and occupied greater percentage cover, no differences in plant density were evident. Our results suggest that, apart from sexual reproduction, many of the trait patterns observed in S. platyphylla are influenced by environmental and habitat conditions within the native and invaded ranges. We conclude that the enemy release hypothesis best explains the results observed for sexual reproduction. In particular, we hypothesise that a release from natural enemies, specifically a pre-dispersal seed predator, may induce reproductive plasticity in S. platyphylla.
- Full Text:
- Date Issued: 2017
- Authors: Kwong, Raelene M , Sagliocco, Jean L , Harms, Nathan E , Butler, Kym L , Green, Peter T , Martin, Grant D
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419287 , vital:71631 , xlink:href="https://doi.org/10.1016/j.aquabot.2017.05.001"
- Description: Understanding why some plant species become invasive is important to predict and prevent future weed threats and identify appropriate management strategies. Many hypotheses have been proposed to explain why plants become invasive, yet few studies have quantitatively compared plant and population parameters between native and introduced range populations to gain an objective perspective on the causes of plant invasion. The present study uses a biogeographical field survey to compare morphological and reproductive traits and abundance between the native range (USA) and two introduced ranges (Australia and South Africa) of Sagittaria platyphylla (Engelm.) J.G. Sm (Alismataceae), a highly invasive freshwater macrophyte. Introduced and native populations differed in sexual reproductive output with the number of achenes per fruiting head and individual achene weight found to be 40% and 50% greater in introduced populations respectively. However, no other morphological traits were found to be consistently different between the native and both introduced ranges, especially after taking into account differences in environmental conditions between the three ranges. Although populations in introduced regions were larger and occupied greater percentage cover, no differences in plant density were evident. Our results suggest that, apart from sexual reproduction, many of the trait patterns observed in S. platyphylla are influenced by environmental and habitat conditions within the native and invaded ranges. We conclude that the enemy release hypothesis best explains the results observed for sexual reproduction. In particular, we hypothesise that a release from natural enemies, specifically a pre-dispersal seed predator, may induce reproductive plasticity in S. platyphylla.
- Full Text:
- Date Issued: 2017
Biogeomorphic aspects of lichen colonisation in part of western Dronning Maud Land, Antarctica
- Authors: Ayres, Gabrielle Alexzena
- Date: 2017
- Subjects: Lichen communities -- Queen Maud Land , Lichens -- Ecology -- Queen Maud Land , Polar regions , Ecology -- Polar regions , Antarctica , Ecology -- Antarctica
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/19713 , vital:22477
- Description: Ice-free regions in Antarctica provide natural laboratories for investigating and modelling change in landscapes and ecosystems. The terrestrial ecosystems in western Dronning Maud Land are potentially critical to improve current understanding of polar ecosystems, however, they remain poorly represented and under-protected. Lichen habitats were used to elucidate geomorphic-biological feedbacks that shape the landscape’s topography and biodiversity, which in turn promote environmental heterogeneity. Environmental parameters acting on two landforms were measured to determine the colonisation and growth of lichens in niche habitats. The habitats were identified and characterised, and topographic heterogeneity was found to control lichen colonisation. Micro-topographical niches provide the most stable environments for colonisation, and are preferred habitats. Lichen-habitat interactions were species specific, and closely related to insolation and moisture availability. The bidirectional relationships between rock weathering and lichen colonisation was ascertained. Results showed that lichens are good indicators of landform heterogeneity, but also promote landform heterogeneity. Given the habitat preferences of specific lichen species, they provide proxy to evaluating environmental responses, especially environmental change. The findings of this research are to be used as baseline data for future studies exploring ecosystem development in emerging landforms.
- Full Text:
- Date Issued: 2017
- Authors: Ayres, Gabrielle Alexzena
- Date: 2017
- Subjects: Lichen communities -- Queen Maud Land , Lichens -- Ecology -- Queen Maud Land , Polar regions , Ecology -- Polar regions , Antarctica , Ecology -- Antarctica
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/19713 , vital:22477
- Description: Ice-free regions in Antarctica provide natural laboratories for investigating and modelling change in landscapes and ecosystems. The terrestrial ecosystems in western Dronning Maud Land are potentially critical to improve current understanding of polar ecosystems, however, they remain poorly represented and under-protected. Lichen habitats were used to elucidate geomorphic-biological feedbacks that shape the landscape’s topography and biodiversity, which in turn promote environmental heterogeneity. Environmental parameters acting on two landforms were measured to determine the colonisation and growth of lichens in niche habitats. The habitats were identified and characterised, and topographic heterogeneity was found to control lichen colonisation. Micro-topographical niches provide the most stable environments for colonisation, and are preferred habitats. Lichen-habitat interactions were species specific, and closely related to insolation and moisture availability. The bidirectional relationships between rock weathering and lichen colonisation was ascertained. Results showed that lichens are good indicators of landform heterogeneity, but also promote landform heterogeneity. Given the habitat preferences of specific lichen species, they provide proxy to evaluating environmental responses, especially environmental change. The findings of this research are to be used as baseline data for future studies exploring ecosystem development in emerging landforms.
- Full Text:
- Date Issued: 2017
Biological and geophysical feedbacks with fire in the Earth System
- Archibald, S, Lehmann, C E, Belcher, C, Bond, W J, Bradstock, R A, Daniau, A L, Dexter, K, Forrestel, E J, Greve, M, He, T, Higgins, Simon I, Ripley, Bradford S
- Authors: Archibald, S , Lehmann, C E , Belcher, C , Bond, W J , Bradstock, R A , Daniau, A L , Dexter, K , Forrestel, E J , Greve, M , He, T , Higgins, Simon I , Ripley, Bradford S
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61413 , vital:28024 , http://iopscience.iop.org/article/10.1088/1748-9326/aa9ead/meta
- Description: Roughly 3% of the Earth’s land surface burns annually, representing a critical exchange of energy and matter between the land and atmosphere via combustion. Fires range from slow smouldering peat fires, to low-intensity surface fires, to intense crown fires, depending on vegetation structure, fuel moisture, prevailing climate, and weather conditions. While the links between biogeochemistry, climate and fire are widely studied within Earth system science, these relationships are also mediated by fuels – namely plants and their litter – which are the product of evolutionary and ecological processes. Fire is a powerful selective force and, over their evolutionary history, plants across diverse clades have evolved numerous traits that either tolerate or promote fire. Here we outline a conceptual framework of how plant traits determine the flammability of ecosystems and interact with climate and weather to influence fire regimes. We explore how these evolutionary and ecological processes scale to impact biogeochemistry and Earth system processes. Finally, we outline several research challenges that, when resolved, will improve our understanding of the role of plant evolution in mediating the fire feedbacks driving Earth system processes. Understanding current patterns of fire and vegetation, as well as patterns of fire over geological time, requires research that incorporates evolutionary biology, ecology, biogeography, and the biogeosciences.
- Full Text:
- Date Issued: 2017
- Authors: Archibald, S , Lehmann, C E , Belcher, C , Bond, W J , Bradstock, R A , Daniau, A L , Dexter, K , Forrestel, E J , Greve, M , He, T , Higgins, Simon I , Ripley, Bradford S
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61413 , vital:28024 , http://iopscience.iop.org/article/10.1088/1748-9326/aa9ead/meta
- Description: Roughly 3% of the Earth’s land surface burns annually, representing a critical exchange of energy and matter between the land and atmosphere via combustion. Fires range from slow smouldering peat fires, to low-intensity surface fires, to intense crown fires, depending on vegetation structure, fuel moisture, prevailing climate, and weather conditions. While the links between biogeochemistry, climate and fire are widely studied within Earth system science, these relationships are also mediated by fuels – namely plants and their litter – which are the product of evolutionary and ecological processes. Fire is a powerful selective force and, over their evolutionary history, plants across diverse clades have evolved numerous traits that either tolerate or promote fire. Here we outline a conceptual framework of how plant traits determine the flammability of ecosystems and interact with climate and weather to influence fire regimes. We explore how these evolutionary and ecological processes scale to impact biogeochemistry and Earth system processes. Finally, we outline several research challenges that, when resolved, will improve our understanding of the role of plant evolution in mediating the fire feedbacks driving Earth system processes. Understanding current patterns of fire and vegetation, as well as patterns of fire over geological time, requires research that incorporates evolutionary biology, ecology, biogeography, and the biogeosciences.
- Full Text:
- Date Issued: 2017
Biological children's experiences and perceptions about having foster children in their households: a case study of Zwelitsha township
- Authors: Ntshongwana, Zintle
- Date: 2017
- Subjects: Foster children -- South Africa -- Eastern Cape Social work with teenagers -- South Africa -- Eastern Cape Foster parents -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10353/3033 , vital:28240
- Description: Most research studies focus on foster children or foster parents, there is dearth of research on the impact of fostering on biological children. This aim of this study was to fill the gap in the literature regarding the experiences of biological children sharing a home with foster children. It also investigated how biological children perceive foster care and challenges encountered by children under foster care. This was achieved through a qualitative research approach. The study was conducted at Zwelitsha Township in King Williams Town. Data was collected through semi-structured interviews with thirty biological children of foster parents and ten social workers in practice. Two focus group discussions were held with twenty foster parents. A focus group discussion guide was used in collecting information during the discussions. Purposive sampling was used in the study and data was analysed according to themes. The major findings revealed that fostering has both positive and negative impacts on biological children and the foster family. Biological children find foster care placement as helpful to children whose parents cannot provide care and protection for children. They gain and learn new knowledge through fostering and are happy about their new siblings in the family since they have companionship. On the other hand, minority of biological children were ambivalent about foster care as they were uncertain between altruistic feelings of making a difference in the lives of needy children against the negative outcomes of fostering. One biological child was negative about foster care. This participant did not like the idea of fostering and did not describe any personal positive outcomes resulting from his fostering experiences. The findings revealed that biological children are unable to voice out their views and ideas regarding foster care placement. The findings also revealed that biological children are not passive observers on how fostering influences their daily lives. Instead, they use strategies to influence fostering processes, especially to protect their foster siblings for the fostering process to be successful, while also having feelings of responsibility for their foster siblings. The findings further suggest that despite the complex nature of the fostering task, professionals should recognise and acknowledge the input of biological children to fostering. It is, therefore, suggested more training should be provided to foster parents to continually include the opinions of their own children in fostering decisions.
- Full Text:
- Date Issued: 2017
- Authors: Ntshongwana, Zintle
- Date: 2017
- Subjects: Foster children -- South Africa -- Eastern Cape Social work with teenagers -- South Africa -- Eastern Cape Foster parents -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10353/3033 , vital:28240
- Description: Most research studies focus on foster children or foster parents, there is dearth of research on the impact of fostering on biological children. This aim of this study was to fill the gap in the literature regarding the experiences of biological children sharing a home with foster children. It also investigated how biological children perceive foster care and challenges encountered by children under foster care. This was achieved through a qualitative research approach. The study was conducted at Zwelitsha Township in King Williams Town. Data was collected through semi-structured interviews with thirty biological children of foster parents and ten social workers in practice. Two focus group discussions were held with twenty foster parents. A focus group discussion guide was used in collecting information during the discussions. Purposive sampling was used in the study and data was analysed according to themes. The major findings revealed that fostering has both positive and negative impacts on biological children and the foster family. Biological children find foster care placement as helpful to children whose parents cannot provide care and protection for children. They gain and learn new knowledge through fostering and are happy about their new siblings in the family since they have companionship. On the other hand, minority of biological children were ambivalent about foster care as they were uncertain between altruistic feelings of making a difference in the lives of needy children against the negative outcomes of fostering. One biological child was negative about foster care. This participant did not like the idea of fostering and did not describe any personal positive outcomes resulting from his fostering experiences. The findings revealed that biological children are unable to voice out their views and ideas regarding foster care placement. The findings also revealed that biological children are not passive observers on how fostering influences their daily lives. Instead, they use strategies to influence fostering processes, especially to protect their foster siblings for the fostering process to be successful, while also having feelings of responsibility for their foster siblings. The findings further suggest that despite the complex nature of the fostering task, professionals should recognise and acknowledge the input of biological children to fostering. It is, therefore, suggested more training should be provided to foster parents to continually include the opinions of their own children in fostering decisions.
- Full Text:
- Date Issued: 2017
Biology and rearing of Ectomyeolis ceratoniae Zeller (Lepidoptera: Pyralidae) carob moth, a pest of multiple crops in South Africa
- Thackeray, S R, Moore, Sean D, Strathie, Lorraine W, Kirkman, W, Hill, Martin P
- Authors: Thackeray, S R , Moore, Sean D , Strathie, Lorraine W , Kirkman, W , Hill, Martin P
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59799 , vital:27652 , https://doi.org/10.4001/003.025.0474
- Description: Ectomyeolis ceratoniae Zeller (Lepidoptera: Pyralidae), carob moth, is a pest of several crops in South Africa. A laboratory culture was established from field-collected larvae infesting mummified pecan nuts. Biological parameters of larvae reared on an artificial diet were measured. The insect goes through five larval instars, and the head capsule sizes of the five instars were determined to be <0.34 mm, 0.35-0.64 mm, 0.65-0.94 mm, 0.95-1.14 mm and >0.15 mm for the five instars, respectively. The insect was reared individually and communally in glass vials, the latter to develop a mass-rearing technique. Developmental time from neonate to pupa was significantly slower when larvae were individually reared (38.18 ±1.2 days) compared to when they were communally reared (24.6 ± 0.65 days). A microsporidian infection (Nosema sp.) was recorded in the culture, causing significantly (fy6 = 14.99, P = 0.0082) higher mortality of communally reared larvae (76.25 % ± 11.87) than individually reared larvae (24.9 % ± 9.6).
- Full Text:
- Date Issued: 2017
- Authors: Thackeray, S R , Moore, Sean D , Strathie, Lorraine W , Kirkman, W , Hill, Martin P
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59799 , vital:27652 , https://doi.org/10.4001/003.025.0474
- Description: Ectomyeolis ceratoniae Zeller (Lepidoptera: Pyralidae), carob moth, is a pest of several crops in South Africa. A laboratory culture was established from field-collected larvae infesting mummified pecan nuts. Biological parameters of larvae reared on an artificial diet were measured. The insect goes through five larval instars, and the head capsule sizes of the five instars were determined to be <0.34 mm, 0.35-0.64 mm, 0.65-0.94 mm, 0.95-1.14 mm and >0.15 mm for the five instars, respectively. The insect was reared individually and communally in glass vials, the latter to develop a mass-rearing technique. Developmental time from neonate to pupa was significantly slower when larvae were individually reared (38.18 ±1.2 days) compared to when they were communally reared (24.6 ± 0.65 days). A microsporidian infection (Nosema sp.) was recorded in the culture, causing significantly (fy6 = 14.99, P = 0.0082) higher mortality of communally reared larvae (76.25 % ± 11.87) than individually reared larvae (24.9 % ± 9.6).
- Full Text:
- Date Issued: 2017
Biomass yield, nutrient content and silage quality of three forage sorghum (Sorghum Bicolour (L.) varieties grown in the semi-arid region of Eastern Cape Province, South Africa
- Gwantshu, Vuyolwethu Hamilton
- Authors: Gwantshu, Vuyolwethu Hamilton
- Date: 2017
- Subjects: Sorghum -- Varieties -- South Africa -- Eastern Cape Sorghum -- South Africa -- Eastern Cape Forage
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9545 , vital:34368
- Description: The study determined the biomass yield, nutrient content and silage quality of forage sorghum varieties. Three varieties were used (King, PAN 868, and PAN 888), in a randomized complete block design (RCBD) with three blocks and three replicates per treatment at the University of Fort Hare research farm. The research study was conducted during the 2016/2017 growing season. The forages were harvested at flowering stage of growth. Biomass yields of fresh forage and dry matter yield were measured. Sub-samples were then dried, milled and analysed for nutrient content. Furthermore, the forage sorghum was ensiled and the silage was analysed for fermentation parameters and nutrient content. The fresh and dry matter biomass yield showed no significant differences (P>0.05) among the varieties. The highest fresh biomass yields were observed in PAN 888 variety was 13400 kg/ha, King had 12600 kg/ha and PAN 868 had 12600 kg/ha. The dry matter yield observed in PAN 888 was 4300.00 DM kg/ha, PAN 868 had 3633.33 DM kg/ha and King yielded 3533.33 DM kg/ha. The different sorghum varieties showed a significant (P<0.01) difference in some chemical composition parameters namely DM, NDIN and NSC. The different sorghum varieties had significant difference (P<0.01) in the silage fermentation parameters of pH, starch and lactic acid. The sorghum silage varieties were significantly (P<0.01) different in the starch fermentation with values of 0.001percent. The sorghum silage varieties were significant different for fermentation of lactic acid with values ranging from 1.99 to 2.62percent. However, PAN 868 and PAN 888 were not different from each other. Similarly, all varieties were different (P<0.05) in the pH with values ranging from 4.16 to 4.53. There were no significant (P>0.05) differences in CP, Fat, NDF, ADF, Hemicellulose, Ash, and ADIN content of the silages. The mineral composition (macro and micro) of the silage were not significantly (P>0.05) different among the varieties. In conclusion, the dry matter production and nutrient content of the three forage sorghum varieties were not significantly different. The silage fermentation quality showed significant (P<0.05) differences among the three sorghum varieties. Therefore, according to the results of this study PAN 888 is the recommended variety to grow in the semi-arid region of the Eastern Cape.
- Full Text:
- Date Issued: 2017
- Authors: Gwantshu, Vuyolwethu Hamilton
- Date: 2017
- Subjects: Sorghum -- Varieties -- South Africa -- Eastern Cape Sorghum -- South Africa -- Eastern Cape Forage
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9545 , vital:34368
- Description: The study determined the biomass yield, nutrient content and silage quality of forage sorghum varieties. Three varieties were used (King, PAN 868, and PAN 888), in a randomized complete block design (RCBD) with three blocks and three replicates per treatment at the University of Fort Hare research farm. The research study was conducted during the 2016/2017 growing season. The forages were harvested at flowering stage of growth. Biomass yields of fresh forage and dry matter yield were measured. Sub-samples were then dried, milled and analysed for nutrient content. Furthermore, the forage sorghum was ensiled and the silage was analysed for fermentation parameters and nutrient content. The fresh and dry matter biomass yield showed no significant differences (P>0.05) among the varieties. The highest fresh biomass yields were observed in PAN 888 variety was 13400 kg/ha, King had 12600 kg/ha and PAN 868 had 12600 kg/ha. The dry matter yield observed in PAN 888 was 4300.00 DM kg/ha, PAN 868 had 3633.33 DM kg/ha and King yielded 3533.33 DM kg/ha. The different sorghum varieties showed a significant (P<0.01) difference in some chemical composition parameters namely DM, NDIN and NSC. The different sorghum varieties had significant difference (P<0.01) in the silage fermentation parameters of pH, starch and lactic acid. The sorghum silage varieties were significantly (P<0.01) different in the starch fermentation with values of 0.001percent. The sorghum silage varieties were significant different for fermentation of lactic acid with values ranging from 1.99 to 2.62percent. However, PAN 868 and PAN 888 were not different from each other. Similarly, all varieties were different (P<0.05) in the pH with values ranging from 4.16 to 4.53. There were no significant (P>0.05) differences in CP, Fat, NDF, ADF, Hemicellulose, Ash, and ADIN content of the silages. The mineral composition (macro and micro) of the silage were not significantly (P>0.05) different among the varieties. In conclusion, the dry matter production and nutrient content of the three forage sorghum varieties were not significantly different. The silage fermentation quality showed significant (P<0.05) differences among the three sorghum varieties. Therefore, according to the results of this study PAN 888 is the recommended variety to grow in the semi-arid region of the Eastern Cape.
- Full Text:
- Date Issued: 2017
Biosynthesis of silver nanoparticles from Acacia mearnsii De Wild stem bark and its antinociceptive properties
- Avoseh, Opeyemi N, Oyedeji, Opeoluwa O, Aremu, Olukayode, Nkeh-Chungag, Benedicta N, Songca, Sandile P, Oyedeji, Adebola Omowunmi, Mohan, Sneha, Oluwafemi, Oluwatobi S
- Authors: Avoseh, Opeyemi N , Oyedeji, Opeoluwa O , Aremu, Olukayode , Nkeh-Chungag, Benedicta N , Songca, Sandile P , Oyedeji, Adebola Omowunmi , Mohan, Sneha , Oluwafemi, Oluwatobi S
- Date: 2017
- Subjects: Metal nanoparticles , Acacia mearnsii , Nociceptive pain
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/1528 , vital:37774 , https://doi.org/10.1080/17518253.2017.1287310
- Description: The biosynthesis of silver nanoparticles (Ag-NPs) using the hydrosol extract of the dry stem bark of Acacia mearnsii as reducing and capping agents, and their antinociceptive properties are hereby reported. By varying the temperature and reaction time, the temporal evolution of the optical and morphological properties of the as-synthesized material was investigated. The NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffractometry (XRD) The optical analyses show that the position of the maximum surface plasmon resonance (SPR) peak is red-shifted as the reaction temperature decreased. The TEM micrographs show that the as-synthesized Ag-NPs are spherical while the X-ray diffraction shows that the material is highly crystalline with face-centered cubic structures. The anti-inflammatory efficacy, analyzed by the formalin model, indicates that the as-synthesized Ag-NPs are very effective, with an inhibition rate of about 76%.
- Full Text:
- Date Issued: 2017
- Authors: Avoseh, Opeyemi N , Oyedeji, Opeoluwa O , Aremu, Olukayode , Nkeh-Chungag, Benedicta N , Songca, Sandile P , Oyedeji, Adebola Omowunmi , Mohan, Sneha , Oluwafemi, Oluwatobi S
- Date: 2017
- Subjects: Metal nanoparticles , Acacia mearnsii , Nociceptive pain
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/1528 , vital:37774 , https://doi.org/10.1080/17518253.2017.1287310
- Description: The biosynthesis of silver nanoparticles (Ag-NPs) using the hydrosol extract of the dry stem bark of Acacia mearnsii as reducing and capping agents, and their antinociceptive properties are hereby reported. By varying the temperature and reaction time, the temporal evolution of the optical and morphological properties of the as-synthesized material was investigated. The NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffractometry (XRD) The optical analyses show that the position of the maximum surface plasmon resonance (SPR) peak is red-shifted as the reaction temperature decreased. The TEM micrographs show that the as-synthesized Ag-NPs are spherical while the X-ray diffraction shows that the material is highly crystalline with face-centered cubic structures. The anti-inflammatory efficacy, analyzed by the formalin model, indicates that the as-synthesized Ag-NPs are very effective, with an inhibition rate of about 76%.
- Full Text:
- Date Issued: 2017
Biotic and abiotic factors promoting the development and proliferation of water hyacinth (eichhornia crassipes (Mart.) Solms-Laub.) in the Wouri Basin (Douala-Cameroon) and environs, with implications for its control
- Voukeng, Sonia Nadege Kenfack
- Authors: Voukeng, Sonia Nadege Kenfack
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7644 , vital:21281
- Description: The Wouri River, situated in the Wouri Basin, is one of the main rivers of the Littoral Region in the city of Douala in Cameroon. It is a source of income and food for the population living around these areas. Since the 1990s, the fishing, transportation, irrigation and sand extraction activities have been impeded by the invasion of aquatic plants, specifically water hyacinth (Eichhornia crassipes [Mart.] Solms-Laubach: Pontederiaceae). Introduced in 1997 to the shore of Lake Chad, water hyacinth has invaded almost 114 ha of the Wouri Basin. Furthermore, Douala, the economic capital of the Cameroon and location for more than 70% of the country’s industries, uses the Wouri River and its tributaries to deposit its effluent and waste, which has worsened the problem of water hyacinth. This thesis examined the ecological and socio-economic impacts of water hyacinth in the Wouri Basin and its possible control. An increase in the nutrients in the water has provided water hyacinth with appropriate conditions for its fast growth during both the rainy and dry seasons. The availability of nutrients in these areas is enhanced by the constant, daily tidal fluctuation of water, providing enough water to the plant for easy nutrient uptake. A survey of the impacts of water hyacinth on aquatic plant communities in the Wouri Basin showed that this plant is able to out-compete native species. Assessment of the impact of water hyacinth on the abundance and diversity of plant communities indicated that at some invaded sites, 65% of the vegetation consisted of water hyacinth. Species found in association with water hyacinth with a high level of abundance-dominance were Pistia stratiotes L. (Araceae) (another invader), Commelina benghalensis L. (Commelinaceae) and Echinochloa pyramidalis (Lam.) Hitchc. & Chase (Poaceae). This component of the study also showed that habitats rich in water hyacinth were poor in diversity, while habitats without water hyacinth were rich in diversity, thus raising awareness of the importance of monitoring invasive aquatic weeds along the Wouri Basin, and of implementing correct control management of all invasive aquatic weeds. Communities living along the invaded rivers are well aware of the range of problems caused by the weed; because as the rivers and water bodies used for fishing, transportation, and sand extraction are progressively invaded by the weed, the riparian population is the first to feel the impact. The impact on people has been noticeable, with an increase in diseases, such as malaria, cholera, diarrhoea, typhoid, filariasis, schistosomiasis, scabies and yellow fever increasing the need for a medicine and hospitalization. Economic losses due to the management of invasive aquatic weeds were recorded, and the Ministry of Environment spent an estimated US$1 200 000 between 2010 and 2015 to manage this scourge. In 2016, an amount of US$160 000 was transferred to these regions to manage invasive aquatic weeds, especially water hyacinth, although manual clearing is still the only method used to control this weed. Isolation of fungi from diseased water hyacinth plants in the Wouri Basin revealed several fungal species, most of which have been isolated from water hyacinth species in water bodies elsewhere, which showed a higher diversity during the dry season than during the rainy season. These fungi included Acremonium zonatum (Sawada). W. Gams (Hypocreaceae), Alternaria eichhorniae Nag Raj & Ponnappa (Pleosporaceae), Chaetomium sp., Colletotrichum sp., Curvularia pallescens Boedjin (Pleosporaceae), Curvalaria sp., Epicoccum nigrum Link (Pleosporaceae), Fusarium sp., Pithomyces chartarum fBerk. & M. A. Curtis) M. B. Ellis (Montagnulaceae), to a lesser extent Myrothecium roridum Tode ex Fr. (Incertae sedis) and Nigrospora sp. Although never released in Cameroon, arthropod biological control agents (Neochetina eichhorniae Warner (Coleoptera, Curculionidae) and N. bruchi Hustache (Coleoptera, Curculionidae)) were present, but their populations were relatively low. The slow spread of the insect population was explained by several factors, among them the tidal fluctuation of water, which has an impact on the population growth of the weevils. Whilst adults may be able to survive tidal fluctuations, larvae are severely impacted by them, contributing to the slow success of biological control. In this study, a significant increase in pathogen-induced disease severity and incidence was noted when Neochetina eichhorniae weevils were present, possibly because larvae tunnelling on the petiole created openings for the penetration of fungal spores. This study highlights the negative impacts of water hyacinth, on the environment, people, and thus economy of Cameroon. The presence of biological control agents and pathogens offers Cameroon the possibility of initiating and properly implementing the biological control option, or an integrated management solution, to manage water hyacinth in the Wouri Basin, and in the rest of Cameroon.
- Full Text:
- Date Issued: 2017
- Authors: Voukeng, Sonia Nadege Kenfack
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7644 , vital:21281
- Description: The Wouri River, situated in the Wouri Basin, is one of the main rivers of the Littoral Region in the city of Douala in Cameroon. It is a source of income and food for the population living around these areas. Since the 1990s, the fishing, transportation, irrigation and sand extraction activities have been impeded by the invasion of aquatic plants, specifically water hyacinth (Eichhornia crassipes [Mart.] Solms-Laubach: Pontederiaceae). Introduced in 1997 to the shore of Lake Chad, water hyacinth has invaded almost 114 ha of the Wouri Basin. Furthermore, Douala, the economic capital of the Cameroon and location for more than 70% of the country’s industries, uses the Wouri River and its tributaries to deposit its effluent and waste, which has worsened the problem of water hyacinth. This thesis examined the ecological and socio-economic impacts of water hyacinth in the Wouri Basin and its possible control. An increase in the nutrients in the water has provided water hyacinth with appropriate conditions for its fast growth during both the rainy and dry seasons. The availability of nutrients in these areas is enhanced by the constant, daily tidal fluctuation of water, providing enough water to the plant for easy nutrient uptake. A survey of the impacts of water hyacinth on aquatic plant communities in the Wouri Basin showed that this plant is able to out-compete native species. Assessment of the impact of water hyacinth on the abundance and diversity of plant communities indicated that at some invaded sites, 65% of the vegetation consisted of water hyacinth. Species found in association with water hyacinth with a high level of abundance-dominance were Pistia stratiotes L. (Araceae) (another invader), Commelina benghalensis L. (Commelinaceae) and Echinochloa pyramidalis (Lam.) Hitchc. & Chase (Poaceae). This component of the study also showed that habitats rich in water hyacinth were poor in diversity, while habitats without water hyacinth were rich in diversity, thus raising awareness of the importance of monitoring invasive aquatic weeds along the Wouri Basin, and of implementing correct control management of all invasive aquatic weeds. Communities living along the invaded rivers are well aware of the range of problems caused by the weed; because as the rivers and water bodies used for fishing, transportation, and sand extraction are progressively invaded by the weed, the riparian population is the first to feel the impact. The impact on people has been noticeable, with an increase in diseases, such as malaria, cholera, diarrhoea, typhoid, filariasis, schistosomiasis, scabies and yellow fever increasing the need for a medicine and hospitalization. Economic losses due to the management of invasive aquatic weeds were recorded, and the Ministry of Environment spent an estimated US$1 200 000 between 2010 and 2015 to manage this scourge. In 2016, an amount of US$160 000 was transferred to these regions to manage invasive aquatic weeds, especially water hyacinth, although manual clearing is still the only method used to control this weed. Isolation of fungi from diseased water hyacinth plants in the Wouri Basin revealed several fungal species, most of which have been isolated from water hyacinth species in water bodies elsewhere, which showed a higher diversity during the dry season than during the rainy season. These fungi included Acremonium zonatum (Sawada). W. Gams (Hypocreaceae), Alternaria eichhorniae Nag Raj & Ponnappa (Pleosporaceae), Chaetomium sp., Colletotrichum sp., Curvularia pallescens Boedjin (Pleosporaceae), Curvalaria sp., Epicoccum nigrum Link (Pleosporaceae), Fusarium sp., Pithomyces chartarum fBerk. & M. A. Curtis) M. B. Ellis (Montagnulaceae), to a lesser extent Myrothecium roridum Tode ex Fr. (Incertae sedis) and Nigrospora sp. Although never released in Cameroon, arthropod biological control agents (Neochetina eichhorniae Warner (Coleoptera, Curculionidae) and N. bruchi Hustache (Coleoptera, Curculionidae)) were present, but their populations were relatively low. The slow spread of the insect population was explained by several factors, among them the tidal fluctuation of water, which has an impact on the population growth of the weevils. Whilst adults may be able to survive tidal fluctuations, larvae are severely impacted by them, contributing to the slow success of biological control. In this study, a significant increase in pathogen-induced disease severity and incidence was noted when Neochetina eichhorniae weevils were present, possibly because larvae tunnelling on the petiole created openings for the penetration of fungal spores. This study highlights the negative impacts of water hyacinth, on the environment, people, and thus economy of Cameroon. The presence of biological control agents and pathogens offers Cameroon the possibility of initiating and properly implementing the biological control option, or an integrated management solution, to manage water hyacinth in the Wouri Basin, and in the rest of Cameroon.
- Full Text:
- Date Issued: 2017
Bird-Monk Seding
- Authors: Rampolokeng, Lesego
- Date: 2017
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/5049 , vital:20758
- Description: This novella is made up of interlinked stories from a rural township in the North West province. The stories of this surface-tranquil place are told through descriptive passages, vignettes, snatches of dialogue, profiles and picture-postcards, all organically interwoven and entwined, and rendered in non-linear fashion. They are set in shebeens, shops, farmlands and the dusty empty spaces of the South African landscape, peopled by police, tourists, and prostitutes of all sorts. The pervasiveness of violence in all forms has the fictional narrator reflecting on the violence of his own past. A smattering of musicians' musings gleaned from interviews and album liner-notes helps him navigate his way through this morass, the rage and frustration that simmers beneath it all.
- Full Text:
- Date Issued: 2017
- Authors: Rampolokeng, Lesego
- Date: 2017
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/5049 , vital:20758
- Description: This novella is made up of interlinked stories from a rural township in the North West province. The stories of this surface-tranquil place are told through descriptive passages, vignettes, snatches of dialogue, profiles and picture-postcards, all organically interwoven and entwined, and rendered in non-linear fashion. They are set in shebeens, shops, farmlands and the dusty empty spaces of the South African landscape, peopled by police, tourists, and prostitutes of all sorts. The pervasiveness of violence in all forms has the fictional narrator reflecting on the violence of his own past. A smattering of musicians' musings gleaned from interviews and album liner-notes helps him navigate his way through this morass, the rage and frustration that simmers beneath it all.
- Full Text:
- Date Issued: 2017
Blessing or curse? : an evaluation of the African Growth Opportunity Act
- Authors: Matenga, Lloyd
- Date: 2017
- Subjects: United States -- African Growth and Opportunity Act Tariff preferences Terms of trade
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10353/8825 , vital:33667
- Description: The core of the commercial relations between the United States (US) and Sub-Saharan African (SSA) countries is primarily based on the advancement of unilateral preferential treatment as envisaged under the African Growth and Opportunity Act (AGOA). AGOA is a bipartisan US legislation promulgated to govern the North-South agreement between the US and SSA countries. Notably, AGOA can be categorized as an exception to the Most Favored Nation (MFN) clause of the General Agreement on Tariffs and Trade (GATT) and consequently under the legal framework of the World Trade Organisation (WTO). The US through the AGOA Extension and Enhancement Act (TPEA) has prolonged the lifespan of AGOA to 2025 in consonance with AGOA and other relevant US legislation. However, there is an ongoing debate as to whether AGOA is working to the advantage or benefit of the eligible SSA countries. This is due to several problematic issues which inter alia relate to the legitimacy of the unilateral preferential treatment, the applicable Rules of Origin (RoO) and the requirement for adoption of robust intellectual property protection regimes as impediments to the enjoyment of AGOA duty and quota free benefits. This study will thus examine the pertinent legal issues underpinning the granting of unilateral preferential treatment in favour of the SSA countries under AGOA and assess the extent to which AGOA complies with or fulfills the purposes and objects of the Enabling Clause.
- Full Text:
- Date Issued: 2017
- Authors: Matenga, Lloyd
- Date: 2017
- Subjects: United States -- African Growth and Opportunity Act Tariff preferences Terms of trade
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10353/8825 , vital:33667
- Description: The core of the commercial relations between the United States (US) and Sub-Saharan African (SSA) countries is primarily based on the advancement of unilateral preferential treatment as envisaged under the African Growth and Opportunity Act (AGOA). AGOA is a bipartisan US legislation promulgated to govern the North-South agreement between the US and SSA countries. Notably, AGOA can be categorized as an exception to the Most Favored Nation (MFN) clause of the General Agreement on Tariffs and Trade (GATT) and consequently under the legal framework of the World Trade Organisation (WTO). The US through the AGOA Extension and Enhancement Act (TPEA) has prolonged the lifespan of AGOA to 2025 in consonance with AGOA and other relevant US legislation. However, there is an ongoing debate as to whether AGOA is working to the advantage or benefit of the eligible SSA countries. This is due to several problematic issues which inter alia relate to the legitimacy of the unilateral preferential treatment, the applicable Rules of Origin (RoO) and the requirement for adoption of robust intellectual property protection regimes as impediments to the enjoyment of AGOA duty and quota free benefits. This study will thus examine the pertinent legal issues underpinning the granting of unilateral preferential treatment in favour of the SSA countries under AGOA and assess the extent to which AGOA complies with or fulfills the purposes and objects of the Enabling Clause.
- Full Text:
- Date Issued: 2017
Boast and bellow, giggle or chatter: gender and verbs of speech in children's fiction
- Authors: Hunt, Sally
- Date: 2017
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/139279 , vital:37722 , ISBN no ISBN , https://www.birmingham.ac.uk/research/activity/corpus/events/2017/cl2017/index.aspx
- Description: Continued gender inequality and gendered representations in the media, broadly construed, remain of concern because of the dialectic relationship between language and society. One source of gender cues is fiction written for and consumed by children. The characters encountered in the pages of a popular book constitute the stuff of identity building and may become role models for thousands of young and impressionable readers.
- Full Text:
- Date Issued: 2017
- Authors: Hunt, Sally
- Date: 2017
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/139279 , vital:37722 , ISBN no ISBN , https://www.birmingham.ac.uk/research/activity/corpus/events/2017/cl2017/index.aspx
- Description: Continued gender inequality and gendered representations in the media, broadly construed, remain of concern because of the dialectic relationship between language and society. One source of gender cues is fiction written for and consumed by children. The characters encountered in the pages of a popular book constitute the stuff of identity building and may become role models for thousands of young and impressionable readers.
- Full Text:
- Date Issued: 2017
Bodies in agitation: Wilma Cruise's recent works
- Authors: Schmahmann, Brenda
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147770 , vital:38670 , https://doi.org/10.1080/00043389.2002.11876996
- Description: Wilma Cruise is probably best known for Strike the Woman Strike the Rock (2000), a public work produced collaboratively with Marcus Holmes which commemorates the march of women on the Union Buildings on 9 August 1956 to protest against the pass laws. This government commission tallies with Cruise's longstanding interest in feminism. Also, through its incorpora tion of sound, the written word and projections of imagery, Strike the Woman Strike the Rock coheres with an interest in combining a diversity of media and art forms that has been evident in her work during the last few years.
- Full Text:
- Date Issued: 2017
- Authors: Schmahmann, Brenda
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147770 , vital:38670 , https://doi.org/10.1080/00043389.2002.11876996
- Description: Wilma Cruise is probably best known for Strike the Woman Strike the Rock (2000), a public work produced collaboratively with Marcus Holmes which commemorates the march of women on the Union Buildings on 9 August 1956 to protest against the pass laws. This government commission tallies with Cruise's longstanding interest in feminism. Also, through its incorpora tion of sound, the written word and projections of imagery, Strike the Woman Strike the Rock coheres with an interest in combining a diversity of media and art forms that has been evident in her work during the last few years.
- Full Text:
- Date Issued: 2017
Book Review: Democratic South Africa's foreign policy
- Authors: Magadla, Siphokazi
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298617 , vital:57721 , xlink:href="https://doi.org/10.1080/10220461.2017.1361863"
- Description: Suzanne Graham's book reviews South Africa's voting behaviour in the United Nations (UN) over a 20-year period (1994–2014), focusing specifically on four themes that featured predominantly in both the policy and rhetoric of South African policymakers during this period: the promotion of human rights and democracy; disarmament and related non-proliferation issues; advancing African interests; and voting on reform of the UN.
- Full Text:
- Date Issued: 2017
- Authors: Magadla, Siphokazi
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298617 , vital:57721 , xlink:href="https://doi.org/10.1080/10220461.2017.1361863"
- Description: Suzanne Graham's book reviews South Africa's voting behaviour in the United Nations (UN) over a 20-year period (1994–2014), focusing specifically on four themes that featured predominantly in both the policy and rhetoric of South African policymakers during this period: the promotion of human rights and democracy; disarmament and related non-proliferation issues; advancing African interests; and voting on reform of the UN.
- Full Text:
- Date Issued: 2017
Book Review: Losing the Plot. Crime, reality and fiction in postapartheid writing
- Authors: Naidu, Samantha
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124942 , vital:35712 , https://dx.doi.org/10.17159/tvl.v.54i2.2980
- Description: In this wide-ranging and impressive ac¬count of postapartheid writing, De Kock describes the “dizzingly heterogeneous corpus” (1) of South African literature after apartheid with the aim of describing its distinctive features and complexity. The methodology is straightforward. De Kock has chosen to read particular liter¬ary works in order to identify broader ideas and trends. To contextualise the study, De Kock deploys the key, perva¬sive notion of “transition”. The notion is variously defined as a “transformative shift from one ‘state’ to another” (2), a “popular mythology” in the “collective consciousness” (3), and as containing a counter-discourse of disillusionment or disorientation, which De Kock refers to as “‘plot loss’” (3). This “plot loss” becomes a central trope in the book to express the social and political chaos of the country, evident in various criminal manifestations of neo-colonialism such as neo-liberal economic policies, new forms of racism, and corruption.
- Full Text:
- Date Issued: 2017
- Authors: Naidu, Samantha
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124942 , vital:35712 , https://dx.doi.org/10.17159/tvl.v.54i2.2980
- Description: In this wide-ranging and impressive ac¬count of postapartheid writing, De Kock describes the “dizzingly heterogeneous corpus” (1) of South African literature after apartheid with the aim of describing its distinctive features and complexity. The methodology is straightforward. De Kock has chosen to read particular liter¬ary works in order to identify broader ideas and trends. To contextualise the study, De Kock deploys the key, perva¬sive notion of “transition”. The notion is variously defined as a “transformative shift from one ‘state’ to another” (2), a “popular mythology” in the “collective consciousness” (3), and as containing a counter-discourse of disillusionment or disorientation, which De Kock refers to as “‘plot loss’” (3). This “plot loss” becomes a central trope in the book to express the social and political chaos of the country, evident in various criminal manifestations of neo-colonialism such as neo-liberal economic policies, new forms of racism, and corruption.
- Full Text:
- Date Issued: 2017
Book review: Shannen L. Hill, The Iconography of Black Consciousness: Biko’s Ghost
- Authors: Nsele, Zamansele
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145653 , vital:38455 , https://0-doi.org.wam.seals.ac.za/10.1177/0021909616634233
- Description: As a student uprising tears across the fabric of post-apartheid campuses, the class of 2015 conjures Black Consciousness to articulate the pervasive epistemic assaults they endure daily at the ivory tower. As if time stood still, as though 1976 never left the scene, the philosophy of Black Consciousness is no lurking spectre; but it is an indispensable affirmation, a restorative life force that gives elaboration and credence to the grammar of black suffering. This is, therefore, a timely book.
- Full Text:
- Date Issued: 2017
- Authors: Nsele, Zamansele
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145653 , vital:38455 , https://0-doi.org.wam.seals.ac.za/10.1177/0021909616634233
- Description: As a student uprising tears across the fabric of post-apartheid campuses, the class of 2015 conjures Black Consciousness to articulate the pervasive epistemic assaults they endure daily at the ivory tower. As if time stood still, as though 1976 never left the scene, the philosophy of Black Consciousness is no lurking spectre; but it is an indispensable affirmation, a restorative life force that gives elaboration and credence to the grammar of black suffering. This is, therefore, a timely book.
- Full Text:
- Date Issued: 2017
Boundary making and boundary crossing in learning pathways access and progression: Voices from the workplace
- Lotz-Sisitka, Heila, Mohanoe, M Nthabiseng, Ramsarup, Preesha, Olvitt, Lausanne L
- Authors: Lotz-Sisitka, Heila , Mohanoe, M Nthabiseng , Ramsarup, Preesha , Olvitt, Lausanne L
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , bulletin
- Identifier: http://hdl.handle.net/10962/436374 , vital:73265 , ISBN bulletin , https://www.saqa.org.za/wp-content/uploads/2023/02/SAQA-Bulletin-2017-1.pdf#page=37
- Description: In the South African Qualifications Authority and Rhodes University (SAQA-Rhodes) partnership research it was found that ‘researching the boundary’is an important unit of analysis in learning pathways research (see Papers 1 and 2 in this Bulle-tin). The researchers have argued that this focus has rele-vance for discussions on articulation, as articulation is a boundary crossing practice39. However, to understand boundary crossing processes, it is important to understand what the boundaries are in learning pathways research and to understand how these boundaries were developed. Bounda-ries in learning pathways are both social and material and are constructed by people’s actions and practices, and can only be resolved through people’s actions and practices. This pa-per–Paper 5–considers the manner in which social-material factors are ‘boundary makers’ in learning pathways, affecting access, mobility, progression and articulation possibilities, with specific reference to articulation between workplace experi-ences and contexts on one hand, and education and training systems on the other. The paper argues for a perspective on the social-material that includes the Critical Realist concept of ‘absence’(Bhaskar, 1993) as an important shaping force in learning pathways research (see Paper 4, in this Bulletin). By identifying ‘boundary making’processes and factors, as articu-lated through ‘voices in the workplace’[one perspective on this issue], the paper identifies key areas for ‘boundary cross-ing’practices in the South African National Qualifications Framework (NQF) system and its associated sub-systems.
- Full Text:
- Date Issued: 2017
- Authors: Lotz-Sisitka, Heila , Mohanoe, M Nthabiseng , Ramsarup, Preesha , Olvitt, Lausanne L
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , bulletin
- Identifier: http://hdl.handle.net/10962/436374 , vital:73265 , ISBN bulletin , https://www.saqa.org.za/wp-content/uploads/2023/02/SAQA-Bulletin-2017-1.pdf#page=37
- Description: In the South African Qualifications Authority and Rhodes University (SAQA-Rhodes) partnership research it was found that ‘researching the boundary’is an important unit of analysis in learning pathways research (see Papers 1 and 2 in this Bulle-tin). The researchers have argued that this focus has rele-vance for discussions on articulation, as articulation is a boundary crossing practice39. However, to understand boundary crossing processes, it is important to understand what the boundaries are in learning pathways research and to understand how these boundaries were developed. Bounda-ries in learning pathways are both social and material and are constructed by people’s actions and practices, and can only be resolved through people’s actions and practices. This pa-per–Paper 5–considers the manner in which social-material factors are ‘boundary makers’ in learning pathways, affecting access, mobility, progression and articulation possibilities, with specific reference to articulation between workplace experi-ences and contexts on one hand, and education and training systems on the other. The paper argues for a perspective on the social-material that includes the Critical Realist concept of ‘absence’(Bhaskar, 1993) as an important shaping force in learning pathways research (see Paper 4, in this Bulletin). By identifying ‘boundary making’processes and factors, as articu-lated through ‘voices in the workplace’[one perspective on this issue], the paper identifies key areas for ‘boundary cross-ing’practices in the South African National Qualifications Framework (NQF) system and its associated sub-systems.
- Full Text:
- Date Issued: 2017
Browsing as a demographic bottleneck in a semi-arid savanna: the effect of size and age on compensatory responses of Vachellia karroo seedlings after simulated herbivory
- Authors: Perumal, Lavinia
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4899 , vital:20741
- Description: Savannas are characterised by a continuous grass layer with scattered trees at varying densities. This vegetation structure is determined by several interacting factors, including fire, herbivory, resource competition and atmospheric CO2 concentration. The preservation of savanna biomes is important and a shift towards a woody biome threatens savanna globally. Bush encroachment which describes the shift towards domination of savannas by C3 woody plants, is especially acute in southern Africa. In semi-arid rangelands, encroachment progresses to dense thickets dominated by thorny and unpalatable bushes and trees. There is evidence that bush encroachment is driven by a reduction in fire and browsing events as well as their interaction. Despite browsing having strong effects on African savannas its isolated role in maintaining tree-grass coexistence has not received as much attention as the role of fire. Therefore the overall aim of this study was to examine the effects of browsing on seedlings of a commonly encroaching species, Vachellia karroo. Browsing was hypothesized to be a demographic release bottleneck for bush encroachment in a semiarid (MAP ~550mm) savanna in the Eastern Cape of South Africa, where fire has been historically rare. In a single study I explored the fate of V. karroo seedlings (less than a year old) following browsing in sub canopy and inter canopy microhabitats. Additionally, I explored how the fate of a seedling changed under high and low tree cover. Firstly, I investigated the type, intensity and frequency of herbivory, from both small and large herbivores, which seedlings were subjected to. Results revealed that browsing was severe and frequent with the majority of seedlings browsed more than twice over a 12 month period. Large browsers such as kudu and impala caused high seedling mortality (46%) while smaller browsers such as invertebrates were more effective at suppressing growth. Microhabitat had little impact on seedling survival, but significantly influenced plant compensatory growth. Reduced seedling growth following browsing was observed in the sub-canopy in comparison to seedling growth in full sunlight in the intercanopy, suggesting V.karroo may be shade intolerant. Secondly, the effect of tree cover on browsed seedlings was determined by quantifying browsing frequency and intensity at high and low tree cover. No differences in browsing intensity and frequency were observed between high and low tree cover. However, high tree cover due to bush encroachment limited seedling above ground growth. The aim of the second study was to investigate how V.karroo survival and growth were influenced by its age and size following simulated browsing. I explored this aim through field and greenhouse experiments. I was particularly interested in testing how plant sensitivity to varying defoliation intensities of repeated browsing varied with plant age (known ages of 6, 12, 16 and 30 weeks). There were large differences in mortality between the different age groups. Furthermore, age interacted with repeated browsing and negatively influenced seedling survival and regrowth. Older seedlings (16 and 30 week old) had greater survival and higher browsing frequencies resulted in greater mortality and reduced growth. The threshold age after which seedlings become more tolerant to herbivory occurs at an age of 28 weeks. Seedlings less than six weeks old experiencing intense (100 % defoliation)browsing had a very low probability (33%) of survival following just a single defoliation. Interestingly, all 16 week old seedlings regrew most of their foliage following a moderate (50%) defoliation with some plants overcompensating for leaf loss. The field study revealed two distinct demographic stages based on age and size (seedlings< 9 mm and saplings >9 mm in stem basal diameter (SBD)). Browsing had a strong negative effect on seedlings, resulting in reduced investment in leaf biomass. These findings suggest plant size and age can be used as robust predictors of a plants vulnerability to browsing. An increase in tree cover requires successful transitions of seedlings to saplings (also known as release). The results of this study suggest that in semi-arid savannas, browsing can impact tree cover through imposing a release bottleneck for tree seedlings and to lesser extent saplings. By limiting tree growth plants are kept in a disturbance trap and will therefore be exposed to not only browsers but fire. These findings also have important implications for tree-grass coexistence dynamics, suggesting that specific size and browsing thresholds should be considered in savanna management.
- Full Text:
- Date Issued: 2017
- Authors: Perumal, Lavinia
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4899 , vital:20741
- Description: Savannas are characterised by a continuous grass layer with scattered trees at varying densities. This vegetation structure is determined by several interacting factors, including fire, herbivory, resource competition and atmospheric CO2 concentration. The preservation of savanna biomes is important and a shift towards a woody biome threatens savanna globally. Bush encroachment which describes the shift towards domination of savannas by C3 woody plants, is especially acute in southern Africa. In semi-arid rangelands, encroachment progresses to dense thickets dominated by thorny and unpalatable bushes and trees. There is evidence that bush encroachment is driven by a reduction in fire and browsing events as well as their interaction. Despite browsing having strong effects on African savannas its isolated role in maintaining tree-grass coexistence has not received as much attention as the role of fire. Therefore the overall aim of this study was to examine the effects of browsing on seedlings of a commonly encroaching species, Vachellia karroo. Browsing was hypothesized to be a demographic release bottleneck for bush encroachment in a semiarid (MAP ~550mm) savanna in the Eastern Cape of South Africa, where fire has been historically rare. In a single study I explored the fate of V. karroo seedlings (less than a year old) following browsing in sub canopy and inter canopy microhabitats. Additionally, I explored how the fate of a seedling changed under high and low tree cover. Firstly, I investigated the type, intensity and frequency of herbivory, from both small and large herbivores, which seedlings were subjected to. Results revealed that browsing was severe and frequent with the majority of seedlings browsed more than twice over a 12 month period. Large browsers such as kudu and impala caused high seedling mortality (46%) while smaller browsers such as invertebrates were more effective at suppressing growth. Microhabitat had little impact on seedling survival, but significantly influenced plant compensatory growth. Reduced seedling growth following browsing was observed in the sub-canopy in comparison to seedling growth in full sunlight in the intercanopy, suggesting V.karroo may be shade intolerant. Secondly, the effect of tree cover on browsed seedlings was determined by quantifying browsing frequency and intensity at high and low tree cover. No differences in browsing intensity and frequency were observed between high and low tree cover. However, high tree cover due to bush encroachment limited seedling above ground growth. The aim of the second study was to investigate how V.karroo survival and growth were influenced by its age and size following simulated browsing. I explored this aim through field and greenhouse experiments. I was particularly interested in testing how plant sensitivity to varying defoliation intensities of repeated browsing varied with plant age (known ages of 6, 12, 16 and 30 weeks). There were large differences in mortality between the different age groups. Furthermore, age interacted with repeated browsing and negatively influenced seedling survival and regrowth. Older seedlings (16 and 30 week old) had greater survival and higher browsing frequencies resulted in greater mortality and reduced growth. The threshold age after which seedlings become more tolerant to herbivory occurs at an age of 28 weeks. Seedlings less than six weeks old experiencing intense (100 % defoliation)browsing had a very low probability (33%) of survival following just a single defoliation. Interestingly, all 16 week old seedlings regrew most of their foliage following a moderate (50%) defoliation with some plants overcompensating for leaf loss. The field study revealed two distinct demographic stages based on age and size (seedlings< 9 mm and saplings >9 mm in stem basal diameter (SBD)). Browsing had a strong negative effect on seedlings, resulting in reduced investment in leaf biomass. These findings suggest plant size and age can be used as robust predictors of a plants vulnerability to browsing. An increase in tree cover requires successful transitions of seedlings to saplings (also known as release). The results of this study suggest that in semi-arid savannas, browsing can impact tree cover through imposing a release bottleneck for tree seedlings and to lesser extent saplings. By limiting tree growth plants are kept in a disturbance trap and will therefore be exposed to not only browsers but fire. These findings also have important implications for tree-grass coexistence dynamics, suggesting that specific size and browsing thresholds should be considered in savanna management.
- Full Text:
- Date Issued: 2017
Buchu and Bobotie in the Boland : culinary heritage in Franschhoek, Western Cape
- Authors: Deavin, Candace
- Date: 2017
- Subjects: Food habits -- South Africa -- Franschhoek -- Cross-cultural studies Plants, Edible -- South Africa -- Franschhoek
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/22254 , vital:29923
- Description: From a confit tomato and potato tumbleweed with buchu to a cured snoek terrine rolled in wilde kruie and Cape bobotie puff pastry with blatjang, chefs that mix indigenous plants and local cuisine with European inspiration and training have proved popular in Franschhoek’s restaurants. In this boland town, the particular constructions of heritage through food, not only showcases regional flavours, but gestures towards the search for an elusive place-based ‘South African’ cuisine that is seen to be rooted in the land. Harkening back to old culinary practices and drawing from their own heritages, Franschhoek’s chefs are foraging, butchering, gathering, growing, fermenting, pickling and cooking over open fires with renewed vigour as they attempt to ground their cuisine, and indeed, themselves, in the soil around them. This thesis considers how, through the culinary repertoire of chefs in Franschhoek, food is constructed as heritage. Within this I look at what heritages are considered desirable, how food’s sensory and symbolic properties are used to their full potential, and who is behind these constructions of culinary heritage. Following on from this, I explore postcolonial and post-apartheid anxieties of place and belonging, as well as desired and emergent identities that are expressed through this culinary heritage.
- Full Text:
- Date Issued: 2017
- Authors: Deavin, Candace
- Date: 2017
- Subjects: Food habits -- South Africa -- Franschhoek -- Cross-cultural studies Plants, Edible -- South Africa -- Franschhoek
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/22254 , vital:29923
- Description: From a confit tomato and potato tumbleweed with buchu to a cured snoek terrine rolled in wilde kruie and Cape bobotie puff pastry with blatjang, chefs that mix indigenous plants and local cuisine with European inspiration and training have proved popular in Franschhoek’s restaurants. In this boland town, the particular constructions of heritage through food, not only showcases regional flavours, but gestures towards the search for an elusive place-based ‘South African’ cuisine that is seen to be rooted in the land. Harkening back to old culinary practices and drawing from their own heritages, Franschhoek’s chefs are foraging, butchering, gathering, growing, fermenting, pickling and cooking over open fires with renewed vigour as they attempt to ground their cuisine, and indeed, themselves, in the soil around them. This thesis considers how, through the culinary repertoire of chefs in Franschhoek, food is constructed as heritage. Within this I look at what heritages are considered desirable, how food’s sensory and symbolic properties are used to their full potential, and who is behind these constructions of culinary heritage. Following on from this, I explore postcolonial and post-apartheid anxieties of place and belonging, as well as desired and emergent identities that are expressed through this culinary heritage.
- Full Text:
- Date Issued: 2017
Bush clumps as indicators of thresholds of change in Arid Thicket mosaic piospheres
- Authors: Schmidt, Anton George
- Date: 2017
- Subjects: Biodiversity conservation Ecological processes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20811 , vital:29403
- Description: In the literature, Arid Thicket transformation by domestic meso-herbivores is purported to follow a state-and-transition model, whereby the ecosystem is initially resilient to herbivory until some threshold is crossed, where after there is a rapid shift to a new alternative stable state. My study represents a first attempt to verify this hypothesis by searching for evidence of stable ecosystem states separated by structural, functional and degradation thresholds in Pruim-Spekboomveld, a variation of Arid Thicket found in the southern Cape of South Africa. In this variation, thicket bush clumps ranging in size from approximately 1 m2 to 100 m2 are interspersed in a matrix of Succulent Karoo vegetation. I correlate structural and functional attributes of the thicket bush clumps and the soil environment beneath them (indicators of ecosystem function) to distance from artificial watering points in four piosphere treatments that have had a different rangeland management history. I mostly fit linear, exponential and sigmoid regression models to my data and use Akaike’s Information Criterion to select the best fitting model. When analysing data on changes in the variation of vegetation production with distance from water using the Normalized Difference Vegetation Index, I additionally fit Generalized Additive Models to the data to take into account more complex predicted patterns of change. Furthermore, I compare the end regions of my data in the piosphere treatments to each other and to similar data collected in a transformed and untransformed reference site. I use both the pattern and extent of transformation within and between the treatments and the reference sites, to verify the existence of stable states and structural, functional and degradation thresholds. I also subject my entire dataset to multivariate analysis using ordination and permutation procedures, in an attempt to corroborate my results from the univariate analysis and to assess the response of bush clump community composition to herbivory. My results indicate that at the scale of a bush clump, a threshold reduction in species richness, functional type diversity, succulent shrub redundancy and cover, palatable shrub cover and bush clump leaf mass below 1.5 m occurs in regions intensively used by domestic meso-herbivores. Furthermore, at the landscape scale there is a threshold reduction in canopy tree cover and bush clump density. In addition to these structural threshold changes, results from a Landscape Function Analysis indicate that soil nutrient cycling, soil water infiltration and soil stability thresholds are crossed at the landscape scale. The soil nutrient cycling threshold is affirmed by soil chemical analyses which indicate that the most rested treatment in the study area has low carbon and nitrogen levels. Furthermore, the keystone species, Portulacaria afra, is unable to re-establish itself in any of the treatments. High pH and potassium levels in all the treatments, relative to the untransformed reference site, indicate that Portulacaria afra (which prefers moderate soil conditions) is unlikely to re-establish in the study area. This finding suggests that all my treatments have crossed a degradation threshold and therefore represent an alternative stable state to the untransformed reference site. My multivariate analysis supports this finding and further indicates that the sampling zones within 25 m of the watering points in the most utilized treatments have crossed a second degradation threshold. This finding is supported by my results that indicate that structural and function thresholds (related to the size, density and ability of bush clumps to capture and retain soil resources) have been crossed. Furthermore, excessively high concentrations of base cations in these sampling zones, relative to the untransformed reference site, affirm the crossing of a degradation threshold. My results on the changes in the variation of vegetation production with distance from water using the Normalized Difference Vegetation Index, support the growing body of evidence in the literature that suggests that increases in the variance of ecosystem processes and services are important indicators of impending ecological thresholds. In general, my findings support the prediction in the literature that domestic meso-herbivore induced transformation of Arid Mosaic Thicket will follow a state-andtransition model.
- Full Text:
- Date Issued: 2017
- Authors: Schmidt, Anton George
- Date: 2017
- Subjects: Biodiversity conservation Ecological processes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20811 , vital:29403
- Description: In the literature, Arid Thicket transformation by domestic meso-herbivores is purported to follow a state-and-transition model, whereby the ecosystem is initially resilient to herbivory until some threshold is crossed, where after there is a rapid shift to a new alternative stable state. My study represents a first attempt to verify this hypothesis by searching for evidence of stable ecosystem states separated by structural, functional and degradation thresholds in Pruim-Spekboomveld, a variation of Arid Thicket found in the southern Cape of South Africa. In this variation, thicket bush clumps ranging in size from approximately 1 m2 to 100 m2 are interspersed in a matrix of Succulent Karoo vegetation. I correlate structural and functional attributes of the thicket bush clumps and the soil environment beneath them (indicators of ecosystem function) to distance from artificial watering points in four piosphere treatments that have had a different rangeland management history. I mostly fit linear, exponential and sigmoid regression models to my data and use Akaike’s Information Criterion to select the best fitting model. When analysing data on changes in the variation of vegetation production with distance from water using the Normalized Difference Vegetation Index, I additionally fit Generalized Additive Models to the data to take into account more complex predicted patterns of change. Furthermore, I compare the end regions of my data in the piosphere treatments to each other and to similar data collected in a transformed and untransformed reference site. I use both the pattern and extent of transformation within and between the treatments and the reference sites, to verify the existence of stable states and structural, functional and degradation thresholds. I also subject my entire dataset to multivariate analysis using ordination and permutation procedures, in an attempt to corroborate my results from the univariate analysis and to assess the response of bush clump community composition to herbivory. My results indicate that at the scale of a bush clump, a threshold reduction in species richness, functional type diversity, succulent shrub redundancy and cover, palatable shrub cover and bush clump leaf mass below 1.5 m occurs in regions intensively used by domestic meso-herbivores. Furthermore, at the landscape scale there is a threshold reduction in canopy tree cover and bush clump density. In addition to these structural threshold changes, results from a Landscape Function Analysis indicate that soil nutrient cycling, soil water infiltration and soil stability thresholds are crossed at the landscape scale. The soil nutrient cycling threshold is affirmed by soil chemical analyses which indicate that the most rested treatment in the study area has low carbon and nitrogen levels. Furthermore, the keystone species, Portulacaria afra, is unable to re-establish itself in any of the treatments. High pH and potassium levels in all the treatments, relative to the untransformed reference site, indicate that Portulacaria afra (which prefers moderate soil conditions) is unlikely to re-establish in the study area. This finding suggests that all my treatments have crossed a degradation threshold and therefore represent an alternative stable state to the untransformed reference site. My multivariate analysis supports this finding and further indicates that the sampling zones within 25 m of the watering points in the most utilized treatments have crossed a second degradation threshold. This finding is supported by my results that indicate that structural and function thresholds (related to the size, density and ability of bush clumps to capture and retain soil resources) have been crossed. Furthermore, excessively high concentrations of base cations in these sampling zones, relative to the untransformed reference site, affirm the crossing of a degradation threshold. My results on the changes in the variation of vegetation production with distance from water using the Normalized Difference Vegetation Index, support the growing body of evidence in the literature that suggests that increases in the variance of ecosystem processes and services are important indicators of impending ecological thresholds. In general, my findings support the prediction in the literature that domestic meso-herbivore induced transformation of Arid Mosaic Thicket will follow a state-andtransition model.
- Full Text:
- Date Issued: 2017
Calcium supplementation commencing before or early in pregnancy, or food fortification with calcium, for preventing hypertensive disorders of pregnancy
- Date: 2017
- Subjects: South Africa Pregnancy Journal article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6187 , vital:45261 , xlink:href="https://DOI:10.1002/14651858.CD011192.pub2"
- Description: Background Pre-eclampsia is considerably more prevalent in low- than high-income countries. One possible explanation for this discrepancy is dietary diKerences, particularly calcium deficiency. Calcium supplementation in the second half of pregnancy reduces the serious consequences of pre-eclampsia and is recommended by the WorldHealthOrganization (WHO) for women with low dietary calcium intake, but has limited eKect on the overallrisk of pre-eclampsia. It is important to establish whether calcium supplementation before and in early pregnancy has added benefit. Such evidence would be justification for population-level fortification of staple foods with calcium. Objectives To determine the eKect of calcium supplementation or food fortification with calcium, commenced before or early in pregnancy and continued at least until mid-pregnancy, on pre-eclampsia and other hypertensive disorders, maternal morbidity and mortality, as well as fetal and neonatal outcomes. Search methods We searched the Cochrane Pregnancy and Childbirth Trials Register (10 August 2017), PubMed (29 June 2017), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (10 August 2017) and reference lists of retrieved studies. Selection criteria Randomised controlled trials of calcium supplementation orfood fortification which include women of child bearing age not yet pregnant, or in early pregnancy. Cluster-RCTs, quasi-RCTs and trials published in abstract form only would have been eligible for inclusion in this review but none were identified. Cross-over designs are not appropriate for this intervention. The scope of this review is to consider interventions including calcium supplementation with or without additional supplements or treatments, compared with placebo or no intervention. Data collection and analysis Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Main results This review is based on one RCT (involving 60 women) which looked at calcium plus additional supplements versus control. The women (who had lowantioxidant status)were in the early stages of pregnancy.We did notidentify any studieswhere supplementation commenced pre-pregnancy. Another RCT comparing calcium versus placebo is ongoing but not yet complete. We did not identify any studies looking at any of our other planned comparisons. Calcium plus antioxidants and other supplements versus placebo We included one small study (involving 60 women with low antioxidantlevels) which was conducted in an academic hospital in Indondesia. The study was at low risk of bias for all domains with the exception of selective reporting, for which it was unclear. Women in the intervention group received calcium (800 mg) plus N-acetylcysteine (200 mg), Cu (2 mg), Zn (15 mg), Mn (0.5 mg) and selenium (100 mcg) and vitamins A (1000 IU), B6 (2.2 mg), B12 (2.2 mcg), C (200 mg), and E (400 IU) versus the placebo control group of women who received similar looking tablets containing iron and folic acid. Both groups received iron (30 mg) and folic acid (400 mcg). Tablets were taken twice daily from eight to 12 weeks of gestation and then throughout pregnancy. The included study found that calcium supplementation plus antioxidants and other supplements may slightly reduce pre-eclampsia (gestational hypertension and proteinuria) (risk ratio (RR) 0.24, 95% confidence interval (CI) 0.06 to 1.01; low-quality evidence), but this is uncertain due to wide confidence intervals just crossing the line of no eKect, and small sample size. It appears that earlypregnancy loss before 20 weeks' gestation (RR 0.06, 95% CI 0.00 to 1.04; moderate-quality evidence) may be slightly reduced by calcium plus antioxidants and other supplements, but this outcome also has wide confidence intervals, which just cross the line of no eKect. Very few events were reported under the composite outcome, severe maternal morbidity and mortality index and no clear diKerence was seen between groups (RR 0.36, 95% CI 0.04 to 3.23; low-quality evidence). However, the included study observed a reduction in the composite outcome pre-eclampsia and/or pregnancy loss at any gestational age (RR 0.13, 95% CI 0.03 to 0.50; moderate-quality evidence), and pregnancy loss/stillbirth at any gestational age (RR 0.06, 95% CI 0.00 to 0.92;moderate-quality evidence)in the calcium plus antioxidant/supplement group. Other outcomes reported (placental abruption, severe pre-eclampsia and preterm birth (less than 37 weeks' gestation)) were too infrequent for meaningful analysis. No data were reported for the outcomes caesarean section, birthweight less 2500 g, Apgar score less than seven at five minutes, death or admission to neonatal intensive care unit (ICU), or pregnancy loss, stillbirth or neonatal death before discharge from hospital. Authors' conclusions The results of this review are based on one small study in which the calcium intervention group also received antioxidants and other supplements. Therefore, we are uncertain whether any of the eKects observed in the study were due to calcium supplementation or not. The evidence in this review was graded low to moderate due to imprecision. There is insuKicient evidence on the eKectiveness or otherwise of pre- or early-pregnancy calcium supplementation, or food fortification for preventing hypertensive disorders of pregnancy. Furtherresearch is needed to determine whether pre- or early-pregnancy supplementation, orfood fortification with calcium is associated with a reduction in adverse pregnancy outcomes such as pre-eclampsia and pregnancy loss. Such studies should be adequately powered, limited to calcium supplementation, placebo-controlled, and include relevant outcomes such as those chosen for this review. There is one ongoing study of calcium supplementation alone versus placebo and this may provide additional evidence in future updates
- Full Text:
- Date Issued: 2017
- Date: 2017
- Subjects: South Africa Pregnancy Journal article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6187 , vital:45261 , xlink:href="https://DOI:10.1002/14651858.CD011192.pub2"
- Description: Background Pre-eclampsia is considerably more prevalent in low- than high-income countries. One possible explanation for this discrepancy is dietary diKerences, particularly calcium deficiency. Calcium supplementation in the second half of pregnancy reduces the serious consequences of pre-eclampsia and is recommended by the WorldHealthOrganization (WHO) for women with low dietary calcium intake, but has limited eKect on the overallrisk of pre-eclampsia. It is important to establish whether calcium supplementation before and in early pregnancy has added benefit. Such evidence would be justification for population-level fortification of staple foods with calcium. Objectives To determine the eKect of calcium supplementation or food fortification with calcium, commenced before or early in pregnancy and continued at least until mid-pregnancy, on pre-eclampsia and other hypertensive disorders, maternal morbidity and mortality, as well as fetal and neonatal outcomes. Search methods We searched the Cochrane Pregnancy and Childbirth Trials Register (10 August 2017), PubMed (29 June 2017), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (10 August 2017) and reference lists of retrieved studies. Selection criteria Randomised controlled trials of calcium supplementation orfood fortification which include women of child bearing age not yet pregnant, or in early pregnancy. Cluster-RCTs, quasi-RCTs and trials published in abstract form only would have been eligible for inclusion in this review but none were identified. Cross-over designs are not appropriate for this intervention. The scope of this review is to consider interventions including calcium supplementation with or without additional supplements or treatments, compared with placebo or no intervention. Data collection and analysis Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Main results This review is based on one RCT (involving 60 women) which looked at calcium plus additional supplements versus control. The women (who had lowantioxidant status)were in the early stages of pregnancy.We did notidentify any studieswhere supplementation commenced pre-pregnancy. Another RCT comparing calcium versus placebo is ongoing but not yet complete. We did not identify any studies looking at any of our other planned comparisons. Calcium plus antioxidants and other supplements versus placebo We included one small study (involving 60 women with low antioxidantlevels) which was conducted in an academic hospital in Indondesia. The study was at low risk of bias for all domains with the exception of selective reporting, for which it was unclear. Women in the intervention group received calcium (800 mg) plus N-acetylcysteine (200 mg), Cu (2 mg), Zn (15 mg), Mn (0.5 mg) and selenium (100 mcg) and vitamins A (1000 IU), B6 (2.2 mg), B12 (2.2 mcg), C (200 mg), and E (400 IU) versus the placebo control group of women who received similar looking tablets containing iron and folic acid. Both groups received iron (30 mg) and folic acid (400 mcg). Tablets were taken twice daily from eight to 12 weeks of gestation and then throughout pregnancy. The included study found that calcium supplementation plus antioxidants and other supplements may slightly reduce pre-eclampsia (gestational hypertension and proteinuria) (risk ratio (RR) 0.24, 95% confidence interval (CI) 0.06 to 1.01; low-quality evidence), but this is uncertain due to wide confidence intervals just crossing the line of no eKect, and small sample size. It appears that earlypregnancy loss before 20 weeks' gestation (RR 0.06, 95% CI 0.00 to 1.04; moderate-quality evidence) may be slightly reduced by calcium plus antioxidants and other supplements, but this outcome also has wide confidence intervals, which just cross the line of no eKect. Very few events were reported under the composite outcome, severe maternal morbidity and mortality index and no clear diKerence was seen between groups (RR 0.36, 95% CI 0.04 to 3.23; low-quality evidence). However, the included study observed a reduction in the composite outcome pre-eclampsia and/or pregnancy loss at any gestational age (RR 0.13, 95% CI 0.03 to 0.50; moderate-quality evidence), and pregnancy loss/stillbirth at any gestational age (RR 0.06, 95% CI 0.00 to 0.92;moderate-quality evidence)in the calcium plus antioxidant/supplement group. Other outcomes reported (placental abruption, severe pre-eclampsia and preterm birth (less than 37 weeks' gestation)) were too infrequent for meaningful analysis. No data were reported for the outcomes caesarean section, birthweight less 2500 g, Apgar score less than seven at five minutes, death or admission to neonatal intensive care unit (ICU), or pregnancy loss, stillbirth or neonatal death before discharge from hospital. Authors' conclusions The results of this review are based on one small study in which the calcium intervention group also received antioxidants and other supplements. Therefore, we are uncertain whether any of the eKects observed in the study were due to calcium supplementation or not. The evidence in this review was graded low to moderate due to imprecision. There is insuKicient evidence on the eKectiveness or otherwise of pre- or early-pregnancy calcium supplementation, or food fortification for preventing hypertensive disorders of pregnancy. Furtherresearch is needed to determine whether pre- or early-pregnancy supplementation, orfood fortification with calcium is associated with a reduction in adverse pregnancy outcomes such as pre-eclampsia and pregnancy loss. Such studies should be adequately powered, limited to calcium supplementation, placebo-controlled, and include relevant outcomes such as those chosen for this review. There is one ongoing study of calcium supplementation alone versus placebo and this may provide additional evidence in future updates
- Full Text:
- Date Issued: 2017