Institutions and economic research: a case of location externalities on agricultural resource allocation in the Kat River basin, South Africa
- Mbatha, Cyril N, Antrobus, Geoffrey G
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142991 , vital:38183 , DOI: 10.1080/03031853.2013.798069
- Description: The Physical Externality Model is used to illustrate the potential limitations of blindly adopting formal models for economic investigation and explanation in varied geographical contexts. As argued by institutional economists for the last hundred years the practice limits the value and relevance of most general economic inquiry. This model postulates that the geographical location of farmers along a given watercourse, in which water is diverted individually, leads to structural inefficiencies that negatively affect the whole farming community. These effects are felt more severely at downstream sites and lead to a status quo where upstream farmers possess relative economic and political advantages over their counterparts elsewhere. In the study of the Kat River basin these predictions appear to be true only in as far as they relate to legal and political allocations and use of water resources.
- Full Text:
- Date Issued: 2010
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142991 , vital:38183 , DOI: 10.1080/03031853.2013.798069
- Description: The Physical Externality Model is used to illustrate the potential limitations of blindly adopting formal models for economic investigation and explanation in varied geographical contexts. As argued by institutional economists for the last hundred years the practice limits the value and relevance of most general economic inquiry. This model postulates that the geographical location of farmers along a given watercourse, in which water is diverted individually, leads to structural inefficiencies that negatively affect the whole farming community. These effects are felt more severely at downstream sites and lead to a status quo where upstream farmers possess relative economic and political advantages over their counterparts elsewhere. In the study of the Kat River basin these predictions appear to be true only in as far as they relate to legal and political allocations and use of water resources.
- Full Text:
- Date Issued: 2010
A Game Theoretic Framework for Cooperative Benefits in South Africa’s land redistribution process: a case of Northern Kwa-Zulu Natal Sugarcane Farmland Transfers (No. 308-2016-5118)
- Mbatha, Cyril N, Antrobus, Geoffrey G
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142958 , vital:38180 , https://ageconsearch.umn.edu/record/96156/
- Description: A good indicator of successful farm redistribution cases has to be the continuation of viable productivity rates in their post transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to argue that cooperation among key stakeholders, which could be enforced through long term contracts between a land buyer, sellers and new owners, would lead to higher productivity levels and other benefits. Additional benefits would, for example, include market related prices paid by a buyer.
- Full Text:
- Date Issued: 2010
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142958 , vital:38180 , https://ageconsearch.umn.edu/record/96156/
- Description: A good indicator of successful farm redistribution cases has to be the continuation of viable productivity rates in their post transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to argue that cooperation among key stakeholders, which could be enforced through long term contracts between a land buyer, sellers and new owners, would lead to higher productivity levels and other benefits. Additional benefits would, for example, include market related prices paid by a buyer.
- Full Text:
- Date Issued: 2010
The weak to strong state involvement and political accountability levels schema
- Authors: Mbatha, Cyril N , Mkize, N N
- Date: 2020
- Subjects: South Africa -- Socio-economic development South Africa -- Politics
- Language: English
- Type: text , Text
- Identifier: http://hdl.handle.net/10962/165364 , vital:41237
- Description: The propositionis that socio-economic development from local to national levels often straddles at least four pathways that are driven by two main variables:the relative strength or weakness of (1) state (and government) involvementin the management of public affairs and resources and (2) the mechanisms for ensuring political accountability. The four pathways, with associated attributes, have presented opportunities or challenges that have promoted or collapsed the sustainable economic development of many post-colonial countries. Using the two main variables we can locate different countries in distinct categories (quadrants) across a two-dimensional Cartesianplane, with state involvement on the Y-axis and state and government accountability to citizens on the X-axis.
- Full Text:
- Date Issued: 2020
- Authors: Mbatha, Cyril N , Mkize, N N
- Date: 2020
- Subjects: South Africa -- Socio-economic development South Africa -- Politics
- Language: English
- Type: text , Text
- Identifier: http://hdl.handle.net/10962/165364 , vital:41237
- Description: The propositionis that socio-economic development from local to national levels often straddles at least four pathways that are driven by two main variables:the relative strength or weakness of (1) state (and government) involvementin the management of public affairs and resources and (2) the mechanisms for ensuring political accountability. The four pathways, with associated attributes, have presented opportunities or challenges that have promoted or collapsed the sustainable economic development of many post-colonial countries. Using the two main variables we can locate different countries in distinct categories (quadrants) across a two-dimensional Cartesianplane, with state involvement on the Y-axis and state and government accountability to citizens on the X-axis.
- Full Text:
- Date Issued: 2020
Institutions and economic research: a case of location externalities on agricultural resource allocation in the Kat River basin, South Africa. A Rejoinder
- Mbatha, Cyril N, Antrobus, Geoffrey G
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143002 , vital:38184 , https://0-doi.org.wam.seals.ac.za/10.1080/03031853.2013.798069
- Description: In Mbatha and Antrobus (2008), an argument was put forward against an importation or adoption of universal models or general theorems to explain locally prevailing socio-economic conditions and predict outcomes in varied geographical contexts such as in the Kat River basin. In response to this argument a comment in this edition argues that our “results are caused by, metaphorically speaking, comparing apples and oranges. If, however, all of the relevant information is taken into account, a simple economic model may suffice to depict the situation within the KRV.” Here we illustrate that the comment comes from a misreading of basic details in the original discussion and in its construction and presentation of an alternative model of the KRV conditions the comment reiterates our original argument that general models and theorems are likely to fail to explain local intricacies primarily because they are not founded on local historical institutions.
- Full Text:
- Date Issued: 2013
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143002 , vital:38184 , https://0-doi.org.wam.seals.ac.za/10.1080/03031853.2013.798069
- Description: In Mbatha and Antrobus (2008), an argument was put forward against an importation or adoption of universal models or general theorems to explain locally prevailing socio-economic conditions and predict outcomes in varied geographical contexts such as in the Kat River basin. In response to this argument a comment in this edition argues that our “results are caused by, metaphorically speaking, comparing apples and oranges. If, however, all of the relevant information is taken into account, a simple economic model may suffice to depict the situation within the KRV.” Here we illustrate that the comment comes from a misreading of basic details in the original discussion and in its construction and presentation of an alternative model of the KRV conditions the comment reiterates our original argument that general models and theorems are likely to fail to explain local intricacies primarily because they are not founded on local historical institutions.
- Full Text:
- Date Issued: 2013
Land price premiums in South Africa's land redistribution process: a case study of Northern Kwazulu-Natal sugarcane farms
- Mbatha, Cyril N, Antrobus, Geoffrey G, Van Rooyen, Jonathan
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G , Van Rooyen, Jonathan
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142980 , vital:38182 , DOI: 10.1080/03031853.2010.491298
- Description: The desire to transfer 30 per cent of commercial farmland into the hands of black South Africans has progressed slower than anticipated. Politicians and government officials have blamed the market approach to the purchase of land for the challenges and failures in the process. An analysis of the transfer of sugarcane land in two districts in KwaZulu-Natal over the period 2000 to 2006 permitted a comparison of the prices paid to commercial farmers both in private transactions and in the case of sales to government. Data did not support the contention that the slow rate of transfer was due to a manipulation of land prices by landowners in an attempt to stall the process. It was concluded that the state lost most of its bargaining power in the land reform market due to the drawn out nature of the land valuation processes.
- Full Text:
- Date Issued: 2010
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G , Van Rooyen, Jonathan
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142980 , vital:38182 , DOI: 10.1080/03031853.2010.491298
- Description: The desire to transfer 30 per cent of commercial farmland into the hands of black South Africans has progressed slower than anticipated. Politicians and government officials have blamed the market approach to the purchase of land for the challenges and failures in the process. An analysis of the transfer of sugarcane land in two districts in KwaZulu-Natal over the period 2000 to 2006 permitted a comparison of the prices paid to commercial farmers both in private transactions and in the case of sales to government. Data did not support the contention that the slow rate of transfer was due to a manipulation of land prices by landowners in an attempt to stall the process. It was concluded that the state lost most of its bargaining power in the land reform market due to the drawn out nature of the land valuation processes.
- Full Text:
- Date Issued: 2010
A cooperative benefits framework in South Africa's land redistribution process: the case of sugarcane farmland transfers
- Mbatha, Cyril N, Antrobus, Geoffrey G
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142922 , vital:38176 , DOI: 10.1080/03031853.2012.741207
- Description: A good indicator of successful land redistribution cases has to be the continuation of viable productivity rates in their post-transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately, negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to illustrate and argue that cooperation among key stakeholders, which could be enforced through long-term contracts between land buyers, sellers and new owners, may lead to maintenance and higher productivity levels and other benefits within the country's land redistribution process.
- Full Text:
- Date Issued: 2013
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142922 , vital:38176 , DOI: 10.1080/03031853.2012.741207
- Description: A good indicator of successful land redistribution cases has to be the continuation of viable productivity rates in their post-transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately, negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to illustrate and argue that cooperation among key stakeholders, which could be enforced through long-term contracts between land buyers, sellers and new owners, may lead to maintenance and higher productivity levels and other benefits within the country's land redistribution process.
- Full Text:
- Date Issued: 2013
Cyril and Early Mabuza in the background before t.v cameras.
- Mabuza, Cyril, Mabuza, Early
- Authors: Mabuza, Cyril , Mabuza, Early
- Date: 19??
- Subjects: UNCATALOGUED
- Type: Image
- Identifier: http://hdl.handle.net/10962/236014 , vital:50367 , DTC-074
- Description: Clipping of an article of Cyril Mabuza and Early Mabuza in the background before TV cameras .. , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/) (NEVER CAHNGE THIS FIELD)
- Full Text: false
- Date Issued: 19??
- Authors: Mabuza, Cyril , Mabuza, Early
- Date: 19??
- Subjects: UNCATALOGUED
- Type: Image
- Identifier: http://hdl.handle.net/10962/236014 , vital:50367 , DTC-074
- Description: Clipping of an article of Cyril Mabuza and Early Mabuza in the background before TV cameras .. , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/) (NEVER CAHNGE THIS FIELD)
- Full Text: false
- Date Issued: 19??
Physical, political and local practice factors as barriers to agricultural development: a case of the Kat River valley, South Africa
- Mbatha, Cyril N, Antrobus, Geoffrey G
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142947 , vital:38178 , DOI: 10.2174/1874923201104010091
- Description: The Kat River Valley, in the Eastern Cape of South Africa, provided a case study against which propositions of determinants of economic development were tested. Physical location was found to matter in determining the level of development and economic leverage which Middle Kat farmers had compared to those downstream in accordance with Bromley's (1982) proposition. Physical location, however, was not a determining factor for farmers in the Upper Kat River who were the least developed. As predicted by Ostrom (1990), high transaction costs stemming from information asymmetries, selfish interests coupled with poor leadership, an unequal distribution of power and the flouting of formal agreements ensured the demise of a once successful Hacop project in the Upper Kat. Finally, Hirschman's (1960) much earlier line of argument was supported in that the nature of proposed development programmes and the compatibility with community values or ‘self images’ contributed to the lack of success of an externally initiated development effort. The findings and conclusion serve an important lesson to economic researchers and decision makers not to duplicate policies for implementation in all geographical and social contexts on the basis of their success elsewhere.
- Full Text:
- Date Issued: 2011
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142947 , vital:38178 , DOI: 10.2174/1874923201104010091
- Description: The Kat River Valley, in the Eastern Cape of South Africa, provided a case study against which propositions of determinants of economic development were tested. Physical location was found to matter in determining the level of development and economic leverage which Middle Kat farmers had compared to those downstream in accordance with Bromley's (1982) proposition. Physical location, however, was not a determining factor for farmers in the Upper Kat River who were the least developed. As predicted by Ostrom (1990), high transaction costs stemming from information asymmetries, selfish interests coupled with poor leadership, an unequal distribution of power and the flouting of formal agreements ensured the demise of a once successful Hacop project in the Upper Kat. Finally, Hirschman's (1960) much earlier line of argument was supported in that the nature of proposed development programmes and the compatibility with community values or ‘self images’ contributed to the lack of success of an externally initiated development effort. The findings and conclusion serve an important lesson to economic researchers and decision makers not to duplicate policies for implementation in all geographical and social contexts on the basis of their success elsewhere.
- Full Text:
- Date Issued: 2011
Landscape drivers of mammal habitat use and richness in a protected area and its surrounding agricultural lands
- Bellón, Beatriz, Henry, Dominic AW, Renaud, Pierre-Cyril, Roque, Fabio de O, Santos, Cyntia Cavalcante, Melo, Isabel, Arvor, Damien, de Vos, Alta
- Authors: Bellón, Beatriz , Henry, Dominic AW , Renaud, Pierre-Cyril , Roque, Fabio de O , Santos, Cyntia Cavalcante , Melo, Isabel , Arvor, Damien , de Vos, Alta
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415873 , vital:71296 , xlink:href="https://doi.org/10.1016/j.agee.2022.107989"
- Description: Protected areas (PAs) are key to conserving biodiversity and ecosystem services globally, but their effectiveness increasingly depends on the ability of the surrounding agricultural areas to support biodiversity and secure connectivity at the landscape level. This requires monitoring the broader multi-use landscapes in which PAs exist and identifying the landscape characteristics that support rich, functional wildlife communities. Here, we investigated the species richness and habitat use patterns of a mammal community in relation to different landscape variables and land use and land cover (LULC) types in a PA and its surrounding agricultural lands in the Cerrado. We first used a hierarchical multi-species occupancy model with input camera trap data and eight landscape variables (vegetation productivity, phenology, and heterogeneity, distance to water, roads and settlements, and the PA, slope, and elevation) to estimate the species richness and habitat use of 29 mammal species across the landscape. We then analyzed the relationships between the species richness and habitat use and the landscape variables at the site level, as well as the distribution of species at the landscape level in relation to the different natural and agricultural LULC types.
- Full Text:
- Date Issued: 2022
- Authors: Bellón, Beatriz , Henry, Dominic AW , Renaud, Pierre-Cyril , Roque, Fabio de O , Santos, Cyntia Cavalcante , Melo, Isabel , Arvor, Damien , de Vos, Alta
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415873 , vital:71296 , xlink:href="https://doi.org/10.1016/j.agee.2022.107989"
- Description: Protected areas (PAs) are key to conserving biodiversity and ecosystem services globally, but their effectiveness increasingly depends on the ability of the surrounding agricultural areas to support biodiversity and secure connectivity at the landscape level. This requires monitoring the broader multi-use landscapes in which PAs exist and identifying the landscape characteristics that support rich, functional wildlife communities. Here, we investigated the species richness and habitat use patterns of a mammal community in relation to different landscape variables and land use and land cover (LULC) types in a PA and its surrounding agricultural lands in the Cerrado. We first used a hierarchical multi-species occupancy model with input camera trap data and eight landscape variables (vegetation productivity, phenology, and heterogeneity, distance to water, roads and settlements, and the PA, slope, and elevation) to estimate the species richness and habitat use of 29 mammal species across the landscape. We then analyzed the relationships between the species richness and habitat use and the landscape variables at the site level, as well as the distribution of species at the landscape level in relation to the different natural and agricultural LULC types.
- Full Text:
- Date Issued: 2022
Preliminary study on the potential use of Fly Ash as a Ventilated Improved Pit Latrine Additive:
- Collings, Dylan, Tandlich, Roman, Dube, Cyril S, Madikizela, Phindile, Ngqwala, Nosiphiwe P, Ahmed, Mustaque
- Authors: Collings, Dylan , Tandlich, Roman , Dube, Cyril S , Madikizela, Phindile , Ngqwala, Nosiphiwe P , Ahmed, Mustaque
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160334 , vital:40436 , https://0-doi.org.wam.seals.ac.za/10.5276/JSWTM/2019.395
- Description: This study describes the results of a series of laboratory experiments on aimed at developing of a protocol for the use of fly ash as a pit additive in the ventilated improved pit latrines (VIPs) in South Africa. Model VIP vaults were prepared in the laboratory and filled with synthetic faecal sludge; and dosed with fly ash in amounts ranging from 5 to 20 % (w/w).
- Full Text:
- Date Issued: 2020
- Authors: Collings, Dylan , Tandlich, Roman , Dube, Cyril S , Madikizela, Phindile , Ngqwala, Nosiphiwe P , Ahmed, Mustaque
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160334 , vital:40436 , https://0-doi.org.wam.seals.ac.za/10.5276/JSWTM/2019.395
- Description: This study describes the results of a series of laboratory experiments on aimed at developing of a protocol for the use of fly ash as a pit additive in the ventilated improved pit latrines (VIPs) in South Africa. Model VIP vaults were prepared in the laboratory and filled with synthetic faecal sludge; and dosed with fly ash in amounts ranging from 5 to 20 % (w/w).
- Full Text:
- Date Issued: 2020
Composition and fate of triclosan in the sludge from wastewater treatment in Grahamstown, South Africa and Tiaret, Algeria
- Authors: Ncube, Mbonisi
- Date: 2017
- Subjects: Sewage sludge , Sewage Purification South Africa Grahamstown , Sewage Purification Algeria Tiaret , Sewage sludge as fertilizer , Anti-infective agents
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65156 , vital:28697
- Description: Physicochemical properties such as pH, specific surface area (SSA), cationic exchange capacity (CEC), loss on ignition (LOI), pathogens, plant nutrients (nitrates, ammonium and phosphates), and heavy metals (manganese, copper, lead and cadmium) were determined for sewage sludge from Grahamstown and Tiaret. The values obtained were log transformed thereafter a t-test at 5 % level of significance was used to test for the difference in each parameter for both sludges. The pH of sludge was determined in 1:3 water, 16 water, 1:3 0.01 M calcium chloride and 1:3 1 M potassium chloride. The pH for Grahamstown and Tiaret sludge were in the ranges of 6.66-7.11 and 7.88-8.18 respectively. The SSA values for Grahamstown and Tiaret were 218 ± 108 and 261 ± 99.9 m2/g, and the CEC values were 119 ± 2.09 and 136 ± 6.03 mEq/100, respectively. The LOI values obtained were 1.33 ± 0.03 and 1.48 ± 0.11 % for Grahamstown and Tiaret, respectively. E. coll and heterotrophic bacteria were the pathogens determined, and were extracted from sludge using sterile saline and nutrient broth. The concentration of E. coll in Grahamstown and Tiaret sludge were 468 ± 7.63 and 7769 ± 1268 CFU/g d.w and for heterotrophic bacteria were 1.17x109 ± 7.42x108 and 1.43x109 ± 9.11 x108 CFU/g d.w. For Grahamstown sludge, the concentration of nitrates, ammonium and phosphates were 55.61 ± 55.20 mg/g d.w, 6.60 ± 2.36 mg/g d.w and 1.40 ± 0.30 mg/g d.w, respectively. For Tiaret sludge, the concentration of nitrates, ammonium and phosphates were 2.56 ± 2.90 mg/g d.w, 0.64 ± 0.45 mg/g d.w and 0.24 ± 0.19 mg/g d.w, respectively. The concentration of Mn, Cu, Pb and Cd in Grahamstown sludge were 423 ± 101, 353 ± 92, 40.2 ± 20 and 0.0 mg/kg d.w respectively, and for Tiaret sludge, the corresponding concentrations were 358± 295, 549±50, 1427± 1352 and 1.54 ± 0.61 mg/kg d.w. Sewage sludge was found to contain Triclosan, and solubility studies of the compound were conducted using sodium deoxycholate and sodium lithocholate. The apparent solubilities and rate constants indicated in brackets of TCS at 37 °C were 35.4 ± 1.21 mg/L (1.28 ± 0.36 Hr-) and 14.4 ± 0.34 mg/L (0.99 ± 0.17 Hr-) in sodium lithocholate and sodium deoxycholate, respectively. The apparent solubilities and rate constants indicated in brackets of TCS at 15 °C were 32.3 ± 0.88 mg/L (2.16 ± 0.80 Hr-) and 14.2 ± 0.39 mg/L (1.02 ± 0.17 Hr-) in sodium lithocholate and sodium deoxycholate, respectively. Triclosan was extracted from sludge using 1 g/L sodium deoxycholate and the determined concentration were 142 ± 33.5 gg/g d.w for Grahamstown sludge and 0-12 gg/g d.w for Tiaret sludge. Finally plant growth studies were conducted on radish and garden cress plants using Grahamstown sludge at 0, 20, 40, 80 and 100 % treatments. Statistical analysis (t-test and Kruskal-Wallis) at 5 % level of significance was done to compare growth parameters between control and different sludge treatments. For radish plants, the values for plant height, root length, number of leaves, leaf length and dry mass were 28.4-80-7 mm, 4.3-44.7 mm, 3.3-17.0 mm, 2.3-4.0 leaves and 6.3-15.3 %, respectively. For garden cress, the values for plant height, root length, number of leaves, leaf length and dry mass were 13.7-25.0 mm, 7.7-20.3 mm, 5.7-8.3 leaves, 3.0-8.3 mm and 8.8-15.0 %, respectively. Twenty percent (20 %) sludge treatment gave the best results in radish and garden cress plants with respect to plant height, root length, number of leaves and dry mass. Triclosan concentration in radish and garden cress plants was below the detection limit of 32.4 gg/g d.w. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2017
- Full Text:
- Date Issued: 2017
- Authors: Ncube, Mbonisi
- Date: 2017
- Subjects: Sewage sludge , Sewage Purification South Africa Grahamstown , Sewage Purification Algeria Tiaret , Sewage sludge as fertilizer , Anti-infective agents
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65156 , vital:28697
- Description: Physicochemical properties such as pH, specific surface area (SSA), cationic exchange capacity (CEC), loss on ignition (LOI), pathogens, plant nutrients (nitrates, ammonium and phosphates), and heavy metals (manganese, copper, lead and cadmium) were determined for sewage sludge from Grahamstown and Tiaret. The values obtained were log transformed thereafter a t-test at 5 % level of significance was used to test for the difference in each parameter for both sludges. The pH of sludge was determined in 1:3 water, 16 water, 1:3 0.01 M calcium chloride and 1:3 1 M potassium chloride. The pH for Grahamstown and Tiaret sludge were in the ranges of 6.66-7.11 and 7.88-8.18 respectively. The SSA values for Grahamstown and Tiaret were 218 ± 108 and 261 ± 99.9 m2/g, and the CEC values were 119 ± 2.09 and 136 ± 6.03 mEq/100, respectively. The LOI values obtained were 1.33 ± 0.03 and 1.48 ± 0.11 % for Grahamstown and Tiaret, respectively. E. coll and heterotrophic bacteria were the pathogens determined, and were extracted from sludge using sterile saline and nutrient broth. The concentration of E. coll in Grahamstown and Tiaret sludge were 468 ± 7.63 and 7769 ± 1268 CFU/g d.w and for heterotrophic bacteria were 1.17x109 ± 7.42x108 and 1.43x109 ± 9.11 x108 CFU/g d.w. For Grahamstown sludge, the concentration of nitrates, ammonium and phosphates were 55.61 ± 55.20 mg/g d.w, 6.60 ± 2.36 mg/g d.w and 1.40 ± 0.30 mg/g d.w, respectively. For Tiaret sludge, the concentration of nitrates, ammonium and phosphates were 2.56 ± 2.90 mg/g d.w, 0.64 ± 0.45 mg/g d.w and 0.24 ± 0.19 mg/g d.w, respectively. The concentration of Mn, Cu, Pb and Cd in Grahamstown sludge were 423 ± 101, 353 ± 92, 40.2 ± 20 and 0.0 mg/kg d.w respectively, and for Tiaret sludge, the corresponding concentrations were 358± 295, 549±50, 1427± 1352 and 1.54 ± 0.61 mg/kg d.w. Sewage sludge was found to contain Triclosan, and solubility studies of the compound were conducted using sodium deoxycholate and sodium lithocholate. The apparent solubilities and rate constants indicated in brackets of TCS at 37 °C were 35.4 ± 1.21 mg/L (1.28 ± 0.36 Hr-) and 14.4 ± 0.34 mg/L (0.99 ± 0.17 Hr-) in sodium lithocholate and sodium deoxycholate, respectively. The apparent solubilities and rate constants indicated in brackets of TCS at 15 °C were 32.3 ± 0.88 mg/L (2.16 ± 0.80 Hr-) and 14.2 ± 0.39 mg/L (1.02 ± 0.17 Hr-) in sodium lithocholate and sodium deoxycholate, respectively. Triclosan was extracted from sludge using 1 g/L sodium deoxycholate and the determined concentration were 142 ± 33.5 gg/g d.w for Grahamstown sludge and 0-12 gg/g d.w for Tiaret sludge. Finally plant growth studies were conducted on radish and garden cress plants using Grahamstown sludge at 0, 20, 40, 80 and 100 % treatments. Statistical analysis (t-test and Kruskal-Wallis) at 5 % level of significance was done to compare growth parameters between control and different sludge treatments. For radish plants, the values for plant height, root length, number of leaves, leaf length and dry mass were 28.4-80-7 mm, 4.3-44.7 mm, 3.3-17.0 mm, 2.3-4.0 leaves and 6.3-15.3 %, respectively. For garden cress, the values for plant height, root length, number of leaves, leaf length and dry mass were 13.7-25.0 mm, 7.7-20.3 mm, 5.7-8.3 leaves, 3.0-8.3 mm and 8.8-15.0 %, respectively. Twenty percent (20 %) sludge treatment gave the best results in radish and garden cress plants with respect to plant height, root length, number of leaves and dry mass. Triclosan concentration in radish and garden cress plants was below the detection limit of 32.4 gg/g d.w. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2017
- Full Text:
- Date Issued: 2017
Benzoyl isothiocyanates derived ligands as potential HIV-1 protease inhibitors and their reactions with gold ions
- Authors: Odame, Felix
- Date: 2016
- Subjects: HIV (Viruses) -- Enzymes Enzyme inhibitors -- Research , Pharmaceutical chemistry Biochemistry
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33228 , vital:32585
- Description: The synthesis and evaluation of benzoyl isothiocyanate derivatives as potential HIV-1 protease inhibitors is presented. The ligands were first designed to fit the protease active site using Autodock 4.2. The design was based on the deNOVO method of drug design in which the active site coordinates from the crystal structure of protease bound to ritonavir was used. An attempt to access the scaffolds designed initially led to the formation of 2,2,4-trimethyl 2,3-dihydro-1H-1,5-benzodiazepin-5-ium isophthalate and 2-2-(3-methylphenyl-1Hbenzimidazole which could not be converted to the desired intermediate. A further attempt led to formation of amino acid and amino acid ester derivatives of benzoyl isothiocyanates which have been fully characterized and the reasons why the desired intermediates were not readily accessible explained. Scaffolds based on the benzoyl isothiocyanate derivatives of structurally diverse diamines were then screened. Sixty compounds have been synthesized and fully characterized using elemental analysis, spectroscopy, GC-MS and twenty-six crystal structures have been discussed. The DFT transition state studies of 11-phenyl- 1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), N-(1Hbenzimidazol-2-yl)benzamide (21), 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea (23), and N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (39), have been carried out and their detailed density functional theory reaction mechanism have be computed. The Bernly algorithm was used in the determination of saddle points (transtions states), and the intrinsic reaction coordinates leading to the determination of intermediates were traced and optimized to a global minimum or in some cases a local minimum was obtained. The cell viability tests of diamine derivatives which was done by exposing white blood cells to the compounds (inhibitors) at 37 °C and a pH of 7.4 showed that 1-(4-bromobenzoyl)-3-[2- ({[(4-bromophenyl)formamido]methanethioyl}amino)phenyl]thiourea (46), 1-(3-chloro benzoyl)-3-[2-({[(3-chlorophenyl)formamido]methanethioyl}amino)phenyl]thiourea (48), 1- (3-bromobenzoyl)-3-[2-({[(3-bromophenyl)formamido]methanethioyl}amino)phenyl] thiourea (49) and 3-benzoyl-1-(4-{[(phenylformamido)methanethioyl]amino}butyl)thiourea (54), in that group of compounds were cytotoxic with EC50 values of 17.04 ± 9.75 μM, 69.20± 38.16 μM, 35.90 ± 20.55 μM and 68.37 ± 26.45 μM, respectively. 4-Bromo-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (32), 4-methoxy-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene]benzamide (33) and 3-chloro-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (37) were also cytotoxic giving EC50 values of 45.47 ± 21.92, 45.09 ±13.79 and 74.94 ± 13.17 μM, respectively. 3-(1,3-Benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (31) and 3-(1,3-benzothiazoyl-2-yl)-1-(4-nitrobenzoyl)thiourea (30) derivatives were also found to be cytotoxic with EC50 values of 1.207 ± 0.58 and 24.08 ±13.14 nM, respectively. 11-(4-Chlorophenyl-1,8,10, 12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (12), 11-(4-methoxyphenyl)-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,9,1-pentaene-13-thione (14), and 11-phenyl-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), were found to be cytotoxic giving EC50 values of 0.152 ± 0.051, 37.96 ± 21.87 and 5.28 ± 2.95 μM, respectively. In the enzyme inhibition studies compound 49 gave a percentage inhibition of 97.03 ± 10.61% at 100 μM, but the fact that it is cytoxic might make it less useful, whilst compounds 19 and 16 had a percentage inhibition of 59.57 ± 13.59% (4-nitro derivative) and 79.97 ± 11.97% (3-nitro derivative) respectively at 100 μM of inhibitor and 20 μM of enzyme (HIV-1 protease). The results suggests that the presence of the nitro group at position 3 (16) and 4 (19) leads to an increase in activity against HIV-1 protease.
- Full Text:
- Date Issued: 2016
- Authors: Odame, Felix
- Date: 2016
- Subjects: HIV (Viruses) -- Enzymes Enzyme inhibitors -- Research , Pharmaceutical chemistry Biochemistry
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33228 , vital:32585
- Description: The synthesis and evaluation of benzoyl isothiocyanate derivatives as potential HIV-1 protease inhibitors is presented. The ligands were first designed to fit the protease active site using Autodock 4.2. The design was based on the deNOVO method of drug design in which the active site coordinates from the crystal structure of protease bound to ritonavir was used. An attempt to access the scaffolds designed initially led to the formation of 2,2,4-trimethyl 2,3-dihydro-1H-1,5-benzodiazepin-5-ium isophthalate and 2-2-(3-methylphenyl-1Hbenzimidazole which could not be converted to the desired intermediate. A further attempt led to formation of amino acid and amino acid ester derivatives of benzoyl isothiocyanates which have been fully characterized and the reasons why the desired intermediates were not readily accessible explained. Scaffolds based on the benzoyl isothiocyanate derivatives of structurally diverse diamines were then screened. Sixty compounds have been synthesized and fully characterized using elemental analysis, spectroscopy, GC-MS and twenty-six crystal structures have been discussed. The DFT transition state studies of 11-phenyl- 1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), N-(1Hbenzimidazol-2-yl)benzamide (21), 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea (23), and N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (39), have been carried out and their detailed density functional theory reaction mechanism have be computed. The Bernly algorithm was used in the determination of saddle points (transtions states), and the intrinsic reaction coordinates leading to the determination of intermediates were traced and optimized to a global minimum or in some cases a local minimum was obtained. The cell viability tests of diamine derivatives which was done by exposing white blood cells to the compounds (inhibitors) at 37 °C and a pH of 7.4 showed that 1-(4-bromobenzoyl)-3-[2- ({[(4-bromophenyl)formamido]methanethioyl}amino)phenyl]thiourea (46), 1-(3-chloro benzoyl)-3-[2-({[(3-chlorophenyl)formamido]methanethioyl}amino)phenyl]thiourea (48), 1- (3-bromobenzoyl)-3-[2-({[(3-bromophenyl)formamido]methanethioyl}amino)phenyl] thiourea (49) and 3-benzoyl-1-(4-{[(phenylformamido)methanethioyl]amino}butyl)thiourea (54), in that group of compounds were cytotoxic with EC50 values of 17.04 ± 9.75 μM, 69.20± 38.16 μM, 35.90 ± 20.55 μM and 68.37 ± 26.45 μM, respectively. 4-Bromo-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (32), 4-methoxy-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene]benzamide (33) and 3-chloro-N-[(9E)-8,10,17-triazatetracyclo[8.7.0.02,7.011,16]heptadeca-1(17),2,4,6,11(16),12,14-heptaen-9-ylidene] benzamide (37) were also cytotoxic giving EC50 values of 45.47 ± 21.92, 45.09 ±13.79 and 74.94 ± 13.17 μM, respectively. 3-(1,3-Benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (31) and 3-(1,3-benzothiazoyl-2-yl)-1-(4-nitrobenzoyl)thiourea (30) derivatives were also found to be cytotoxic with EC50 values of 1.207 ± 0.58 and 24.08 ±13.14 nM, respectively. 11-(4-Chlorophenyl-1,8,10, 12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (12), 11-(4-methoxyphenyl)-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,9,1-pentaene-13-thione (14), and 11-phenyl-1,8,10,12-tetraazatricyclo[7.4.0.02,7]trideca-2(7),3,5,9,11-pentaene-13-thione (20), were found to be cytotoxic giving EC50 values of 0.152 ± 0.051, 37.96 ± 21.87 and 5.28 ± 2.95 μM, respectively. In the enzyme inhibition studies compound 49 gave a percentage inhibition of 97.03 ± 10.61% at 100 μM, but the fact that it is cytoxic might make it less useful, whilst compounds 19 and 16 had a percentage inhibition of 59.57 ± 13.59% (4-nitro derivative) and 79.97 ± 11.97% (3-nitro derivative) respectively at 100 μM of inhibitor and 20 μM of enzyme (HIV-1 protease). The results suggests that the presence of the nitro group at position 3 (16) and 4 (19) leads to an increase in activity against HIV-1 protease.
- Full Text:
- Date Issued: 2016
An evening that will linger on.
- Tito, Dudlely, Petersen, Julius, Michael, Peterson, Oscar, Ntsele, Pych, Underson, Gill, Green, Cyril, Gontsana, Lulu
- Authors: Tito, Dudlely , Petersen , Julius, Michael , Peterson, Oscar , Ntsele, Pych , Underson, Gill , Green, Cyril , Gontsana, Lulu
- Date: 19??
- Subjects: UNCATALOGUED
- Type: Image
- Identifier: http://hdl.handle.net/10962/237370 , vital:50509 , DTC-173
- Description: Clippings of an article about the opening of the Downbeat Jazz club and Dudlely Tito playing a tenor sax and Winston Petersen playing an alto sax. , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/) (NEVER CAHNGE THIS FIELD)
- Full Text: false
- Date Issued: 19??
- Authors: Tito, Dudlely , Petersen , Julius, Michael , Peterson, Oscar , Ntsele, Pych , Underson, Gill , Green, Cyril , Gontsana, Lulu
- Date: 19??
- Subjects: UNCATALOGUED
- Type: Image
- Identifier: http://hdl.handle.net/10962/237370 , vital:50509 , DTC-173
- Description: Clippings of an article about the opening of the Downbeat Jazz club and Dudlely Tito playing a tenor sax and Winston Petersen playing an alto sax. , Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/) (NEVER CAHNGE THIS FIELD)
- Full Text: false
- Date Issued: 19??
Traditional and Christian elements in contemporary pictorial African art in South Africa with special reference to the works of John Muafangejo, Azariah Mbatha and Dan Rakgoathe
- Authors: Kilian, Julie
- Date: 1987
- Subjects: Muafangejo, John N., 1943-1987 -- Criticism and interpretation Christian art and symbolism -- South Africa Mbatha, Azariah -- Criticism and interpretation Rakgoathe, Dan -- Criticism and interpretation Art, Black -- South Africa
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2483 , http://hdl.handle.net/10962/d1012635
- Description: Art is the outward, visual manifestation of the undying soul of a people. The genius displayed in the day to day articles produced in traditional tribal society is equally present in the art produced by the Contemporary African Artist. The Contemporary African Artist finds himself in an interesting position, in that he is, at one time, a part of two different worlds, two different cultures, has taken place, the and his art provides evidence of the acculturation that coming together of indigenous, traditional African culture and 'European' or 'Western' culture. It follows that the contemporary African artist's work would display characteristics and elements derived from both of these worlds, since art is not created in a vacuum, but is, invariably, the outward, visible expression and symbol of an artist's environment, culture, emotional and intellectual responses and his beliefs. The study of Contemporary African Art reveals that despite the many divergences from the traditional or classic forms, a great many traditional influences and characteristics still persist in the same. An analysis of Contemporary African Art will also show that a significant body of works bear a marked influence of Christian teachings and biblical themes, as well as the influence of exposure to various forms of Swedish Medieval, Byzantine, Romanesque and Carolingian art.
- Full Text:
- Date Issued: 1987
- Authors: Kilian, Julie
- Date: 1987
- Subjects: Muafangejo, John N., 1943-1987 -- Criticism and interpretation Christian art and symbolism -- South Africa Mbatha, Azariah -- Criticism and interpretation Rakgoathe, Dan -- Criticism and interpretation Art, Black -- South Africa
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2483 , http://hdl.handle.net/10962/d1012635
- Description: Art is the outward, visual manifestation of the undying soul of a people. The genius displayed in the day to day articles produced in traditional tribal society is equally present in the art produced by the Contemporary African Artist. The Contemporary African Artist finds himself in an interesting position, in that he is, at one time, a part of two different worlds, two different cultures, has taken place, the and his art provides evidence of the acculturation that coming together of indigenous, traditional African culture and 'European' or 'Western' culture. It follows that the contemporary African artist's work would display characteristics and elements derived from both of these worlds, since art is not created in a vacuum, but is, invariably, the outward, visible expression and symbol of an artist's environment, culture, emotional and intellectual responses and his beliefs. The study of Contemporary African Art reveals that despite the many divergences from the traditional or classic forms, a great many traditional influences and characteristics still persist in the same. An analysis of Contemporary African Art will also show that a significant body of works bear a marked influence of Christian teachings and biblical themes, as well as the influence of exposure to various forms of Swedish Medieval, Byzantine, Romanesque and Carolingian art.
- Full Text:
- Date Issued: 1987
Western influences on the Zulu system of personal naming
- Authors: Dickens, Sybil Maureen
- Date: 1986
- Subjects: Zulu language -- Etymology -- Names , Names, Personal -- Zulu , Names, Zulu
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2378 , http://hdl.handle.net/10962/d1007158 , Zulu language -- Etymology -- Names , Names, Personal -- Zulu , Names, Zulu
- Full Text:
- Date Issued: 1986
- Authors: Dickens, Sybil Maureen
- Date: 1986
- Subjects: Zulu language -- Etymology -- Names , Names, Personal -- Zulu , Names, Zulu
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2378 , http://hdl.handle.net/10962/d1007158 , Zulu language -- Etymology -- Names , Names, Personal -- Zulu , Names, Zulu
- Full Text:
- Date Issued: 1986
Woody species composition and congregant appreciation of the cultural and spiritual services provided by cemeteries and church gardens in Grahamstown, South Africa
- Authors: De Lacy, Peter James Gerard
- Date: 2015
- Subjects: Plants -- Religious aspects , Cemeteries -- South Africa -- Grahamstown , Woody plants -- South Africa -- Grahamstown , Church gardens -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4783 , http://hdl.handle.net/10962/d1016401
- Description: Urbanization has increased rapidly throughout the world. The densification of urban areas has greatly reduced the number of natural areas occurring within the urban environment as well as impacting the ecosystem services that these areas provide. Urban greening and sustainable practices have been advocated as a means to once again provide the urban population with ecosystem services. Sacred natural areas that occur in surrounding forest, temple and cemetery sites have been known harbour a variety of biological diversity, as well as provide people with a number of cultural and spiritual benefits. Much of the literature on sacred natural sites comes from rural or eastern countries, leaving a large gap in the knowledge pertaining to information on these sites in both developed nations as well as urban areas. The aim of this study was to determine the abundance and composition of woody species, as well as the spiritual and cultural significance of sacred natural sites in Grahamstown. This study defined a sacred urban area as any form of garden surrounding a church, temple or mosque, as well as cemeteries. It looked at a total of 28 church gardens, one Hindu garden, one Mosque garden and five cemeteries in Grahamstown, South Africa. For each site the area was calculated and a tree and shrub inventory was done for all individuals above 1.5 m tall. Church/cemetery age, denomination and appearance were recorded as well as soil samples collected. An ordination of the data was done to summarize the community data, relating the community variation to environmental gradients. Questionnaires were completed by congregants who attended a religious building with a garden, as well as those that were not surrounded by a garden. These questionnaires were used to determine the cultural, spiritual and aesthetic value of trees and the sacred area, as well as the perceived and felt benefits that these areas provide. Those that were completed by congregants without gardens looked to find out whether or not it was believed that these areas would improve their experiences. There was an average plant density of 106.1 woody plants per hectare, with a total of 139 different species encountered. Of these, 56 percent were exotic species. This is slightly lower than that of studies done elsewhere in the world, but may be due to the omission of non-woody ornamentals and lawn species in this study. Of the top 11 most frequently occurring species, only two were indigenous. There was generally low similarity between plant assemblages found at the different sites. A significantly positive relationship was found between site size and woody plant basal area as well as the total number of woody plants. Site age and religious denomination had little influence on woody plant density, basal area, species richness or woody plant abundance. Congregants stated that a garden surrounding a religious building improved both their spiritual and aesthetic experiences. Stated spiritual and aesthetic experience was significantly influenced by basal area, while abundance significantly influenced stated aesthetic experience. Greenery was therefore important to many of the congregants, however, the species that were present were less influential. A greater sample size from a variety of religions and sacred areas within urban environments throughout the world would prove to be an interesting comparison for future research.
- Full Text:
- Date Issued: 2015
- Authors: De Lacy, Peter James Gerard
- Date: 2015
- Subjects: Plants -- Religious aspects , Cemeteries -- South Africa -- Grahamstown , Woody plants -- South Africa -- Grahamstown , Church gardens -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4783 , http://hdl.handle.net/10962/d1016401
- Description: Urbanization has increased rapidly throughout the world. The densification of urban areas has greatly reduced the number of natural areas occurring within the urban environment as well as impacting the ecosystem services that these areas provide. Urban greening and sustainable practices have been advocated as a means to once again provide the urban population with ecosystem services. Sacred natural areas that occur in surrounding forest, temple and cemetery sites have been known harbour a variety of biological diversity, as well as provide people with a number of cultural and spiritual benefits. Much of the literature on sacred natural sites comes from rural or eastern countries, leaving a large gap in the knowledge pertaining to information on these sites in both developed nations as well as urban areas. The aim of this study was to determine the abundance and composition of woody species, as well as the spiritual and cultural significance of sacred natural sites in Grahamstown. This study defined a sacred urban area as any form of garden surrounding a church, temple or mosque, as well as cemeteries. It looked at a total of 28 church gardens, one Hindu garden, one Mosque garden and five cemeteries in Grahamstown, South Africa. For each site the area was calculated and a tree and shrub inventory was done for all individuals above 1.5 m tall. Church/cemetery age, denomination and appearance were recorded as well as soil samples collected. An ordination of the data was done to summarize the community data, relating the community variation to environmental gradients. Questionnaires were completed by congregants who attended a religious building with a garden, as well as those that were not surrounded by a garden. These questionnaires were used to determine the cultural, spiritual and aesthetic value of trees and the sacred area, as well as the perceived and felt benefits that these areas provide. Those that were completed by congregants without gardens looked to find out whether or not it was believed that these areas would improve their experiences. There was an average plant density of 106.1 woody plants per hectare, with a total of 139 different species encountered. Of these, 56 percent were exotic species. This is slightly lower than that of studies done elsewhere in the world, but may be due to the omission of non-woody ornamentals and lawn species in this study. Of the top 11 most frequently occurring species, only two were indigenous. There was generally low similarity between plant assemblages found at the different sites. A significantly positive relationship was found between site size and woody plant basal area as well as the total number of woody plants. Site age and religious denomination had little influence on woody plant density, basal area, species richness or woody plant abundance. Congregants stated that a garden surrounding a religious building improved both their spiritual and aesthetic experiences. Stated spiritual and aesthetic experience was significantly influenced by basal area, while abundance significantly influenced stated aesthetic experience. Greenery was therefore important to many of the congregants, however, the species that were present were less influential. A greater sample size from a variety of religions and sacred areas within urban environments throughout the world would prove to be an interesting comparison for future research.
- Full Text:
- Date Issued: 2015
The Eucharist and history
- Paterson, Torquil John Macleod
- Authors: Paterson, Torquil John Macleod
- Date: 1990
- Subjects: Lord's Supper , History -- Religious aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1311 , http://hdl.handle.net/10962/d1018262
- Description: The thesis delineates an existential view of history, in which the eternal is defined as the ground of authentic human life which underlies true historical action. The historical is the manifestation of the eternal in the unique moment, and redefines the ahistorical conditions of human life. The ahistorical is the social and ideological conditioning of all human knowledge, usually presented in terms of various kinds of myth and ritual . The ahistorical contains both good and bad elements, but always has the tendency to become oppressive and is therefore constantly in conflict with the historical. The life of Jesus is described as the perfect expression of the eternal in true historical action, by which he came into conflict with the ahistorical of his society, as expressed in his death. By his resurrection, his life breaks the limitations of time and becomes transformative enabling all subsequent historical action. The eucharist is described as engaging with each of these dimensions of our existence. By being itself a ritual action containing a myth, the eucharist has an ahistorical form and therefore easily engages with the ahistorical dimensions of society. However, without a constant dialogue with the historical, the eucharist, as an ahistorical medium, can become allied to the dominant forces of society and become a means of oppression. The eucharist has at its centre the remembrance of the historical action of Jesus. True historical action in the present will result from a proper hermeneutic of the gospels. The eucharistic anamnesis must be regarded as part of the wider search for a relevant contemporary christology. The eucharist remembers the Last Supper, which is a parable of the whole life of Jesus and a prelude to his death and is a sacrifice in that it has a sacrificial form, and leads to our historical action, which will usually take the form of a conflict with the ahistorical and have sacrificial dimensions. The eternal only becomes present in our historical action, but the eucharist, by uniting us with the transforming power of the death and resurrection of Jesus, is a powerful aid to such action. The eucharist also provides the opportunity for resonances between Jesus and the ground of our being, thus enabling deep shifts of attitude and consciousness. Three fundamental prerequisites for human life are isolated and related to the eucharist: belonging, nurturing and giving. In order for the eucharist to ennable historical action is must hold these dimensions in tension. In its actual form it does this through the balance between the Words of Institution and the Epiclesis, which, in turn, provide the christological ground of the eucharist and relate this to the present through a particular pneumatology. The real presence is described by the thesis in a way which connects the eucharistic presence with the historical Jesus and leads to our historical action. Finally, some consequences of the thesis for Eucharistic practice are suggested. The relationship between the ahistorical form of the eucharist and the anamnesis is important. In this way the eucharist objectifies the ahistorical, reflects on this in terms of the historical action of Jesus, and reforms the ahistorical by modelling a response. This should lead to a more authentic expression of the eternal in the contemporary world
- Full Text:
- Date Issued: 1990
- Authors: Paterson, Torquil John Macleod
- Date: 1990
- Subjects: Lord's Supper , History -- Religious aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1311 , http://hdl.handle.net/10962/d1018262
- Description: The thesis delineates an existential view of history, in which the eternal is defined as the ground of authentic human life which underlies true historical action. The historical is the manifestation of the eternal in the unique moment, and redefines the ahistorical conditions of human life. The ahistorical is the social and ideological conditioning of all human knowledge, usually presented in terms of various kinds of myth and ritual . The ahistorical contains both good and bad elements, but always has the tendency to become oppressive and is therefore constantly in conflict with the historical. The life of Jesus is described as the perfect expression of the eternal in true historical action, by which he came into conflict with the ahistorical of his society, as expressed in his death. By his resurrection, his life breaks the limitations of time and becomes transformative enabling all subsequent historical action. The eucharist is described as engaging with each of these dimensions of our existence. By being itself a ritual action containing a myth, the eucharist has an ahistorical form and therefore easily engages with the ahistorical dimensions of society. However, without a constant dialogue with the historical, the eucharist, as an ahistorical medium, can become allied to the dominant forces of society and become a means of oppression. The eucharist has at its centre the remembrance of the historical action of Jesus. True historical action in the present will result from a proper hermeneutic of the gospels. The eucharistic anamnesis must be regarded as part of the wider search for a relevant contemporary christology. The eucharist remembers the Last Supper, which is a parable of the whole life of Jesus and a prelude to his death and is a sacrifice in that it has a sacrificial form, and leads to our historical action, which will usually take the form of a conflict with the ahistorical and have sacrificial dimensions. The eternal only becomes present in our historical action, but the eucharist, by uniting us with the transforming power of the death and resurrection of Jesus, is a powerful aid to such action. The eucharist also provides the opportunity for resonances between Jesus and the ground of our being, thus enabling deep shifts of attitude and consciousness. Three fundamental prerequisites for human life are isolated and related to the eucharist: belonging, nurturing and giving. In order for the eucharist to ennable historical action is must hold these dimensions in tension. In its actual form it does this through the balance between the Words of Institution and the Epiclesis, which, in turn, provide the christological ground of the eucharist and relate this to the present through a particular pneumatology. The real presence is described by the thesis in a way which connects the eucharistic presence with the historical Jesus and leads to our historical action. Finally, some consequences of the thesis for Eucharistic practice are suggested. The relationship between the ahistorical form of the eucharist and the anamnesis is important. In this way the eucharist objectifies the ahistorical, reflects on this in terms of the historical action of Jesus, and reforms the ahistorical by modelling a response. This should lead to a more authentic expression of the eternal in the contemporary world
- Full Text:
- Date Issued: 1990
Diet of the yellow mongoose (Cynictis penicillata) in the Albany Thicket Biome of South Africa
- Authors: Bizani, Mfundo
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11796 , http://hdl.handle.net/10353/d1019840
- Description: The dietary habits of the yellow mongoose Cynictis penicillata were studied in the Albany Thicket Biome of South Africa (Great Fish River Reserve, Eastern Cape). The diet was investigated through the analysis of 1,056 scats that were sampled over a period of 7 years (2005−2009 and 2011−2012) mainly in three similar sites (Kelarny, Grasslands and Junction 10) that were used by at least three families or groups of yellow mongooses. Scats were collected near latrine sites, labelled and stored in a freezer. In the laboratory, scats were oven dried for a period of 24 hours at 50 C. Diet was determined by identifying undigested food remains in the scats. Hair samples were examined under the compound microscope to identify which mammals were ingested. In the field, both arthropod and small mammal abundance were determined in order to evaluate whether yellow mongooses are opportunistic or specialist feeders. Furthermore, inter-annual (2006–2008) and inter-group/inter-site variations in the diet were assessed. Based on faecal analysis, arthropods were the principal prey, while small mammals acted as supplementary food item. Other food categories like vegetation, reptiles and birds were only ingested or preyed upon infrequently. Intermediate dietary diversity, and low standardised diet breadth indices were obtained for all seasons, as well as for the whole sampling period. The diet overlaps calculated for pairs of seasons were very high and did not differ substantially. However, the diet of the yellow mongoose varied seasonally, yearly and between groups (sites), mostly due to variations in arthropod and small mammal consumption. Food availability displayed an increase in biomass of both small mammals and arthropods in summer and autumn. Results obtained in this study could suggest that the yellow mongoose at the GFRR is insectivorous by preferring to feed on insects (and arthropods in general) when both insects and rodents are abundant. However the fact that its diet varies both seasonally, yearly and locally, as well as the presence of remains of other food categories in the scats, indicates that this species is rather an opportunistic, generalist feeder than an insect specialist.
- Full Text:
- Date Issued: 2014
- Authors: Bizani, Mfundo
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11796 , http://hdl.handle.net/10353/d1019840
- Description: The dietary habits of the yellow mongoose Cynictis penicillata were studied in the Albany Thicket Biome of South Africa (Great Fish River Reserve, Eastern Cape). The diet was investigated through the analysis of 1,056 scats that were sampled over a period of 7 years (2005−2009 and 2011−2012) mainly in three similar sites (Kelarny, Grasslands and Junction 10) that were used by at least three families or groups of yellow mongooses. Scats were collected near latrine sites, labelled and stored in a freezer. In the laboratory, scats were oven dried for a period of 24 hours at 50 C. Diet was determined by identifying undigested food remains in the scats. Hair samples were examined under the compound microscope to identify which mammals were ingested. In the field, both arthropod and small mammal abundance were determined in order to evaluate whether yellow mongooses are opportunistic or specialist feeders. Furthermore, inter-annual (2006–2008) and inter-group/inter-site variations in the diet were assessed. Based on faecal analysis, arthropods were the principal prey, while small mammals acted as supplementary food item. Other food categories like vegetation, reptiles and birds were only ingested or preyed upon infrequently. Intermediate dietary diversity, and low standardised diet breadth indices were obtained for all seasons, as well as for the whole sampling period. The diet overlaps calculated for pairs of seasons were very high and did not differ substantially. However, the diet of the yellow mongoose varied seasonally, yearly and between groups (sites), mostly due to variations in arthropod and small mammal consumption. Food availability displayed an increase in biomass of both small mammals and arthropods in summer and autumn. Results obtained in this study could suggest that the yellow mongoose at the GFRR is insectivorous by preferring to feed on insects (and arthropods in general) when both insects and rodents are abundant. However the fact that its diet varies both seasonally, yearly and locally, as well as the presence of remains of other food categories in the scats, indicates that this species is rather an opportunistic, generalist feeder than an insect specialist.
- Full Text:
- Date Issued: 2014
Records of the inquest into the murder of Matthew Goniwe, Sparrow Mkonto, Fort Calata and Sicelo Mhlauli near Port Elizabeth on 27 June 1985
- Authors: Goniwe Inquest
- Subjects: Goniwe, Matthew 1946-1985 , Calata, Fort -1985 , Mkonto, Sparrow -1985 , Mhlauli, Sicelo -1985 , South Africa South African Defence Force , South African Police , Violent deaths South Africa , Inquests South Africa , Colonel Du Plessis, Lourens SADF , General Van der Westhuizen, C P SADF , Colonel Jonker, J SAP , Bozalek, Lee Legal Resources Centre, Cape Town , Makhaula, Gladdwell Cradock Residents Association (CRADORA) , Fouche, Henri , Cradock Workers Union , Holomisa, Bantu, 1955- , Joubert, A J M , Lessons learnt from past revolutionay wars by Brigadier C.A. Fraser, SM
- Language: English , Afrikaans
- Type: legal case and case notes , text
- Identifier: http://hdl.handle.net/10962/165046 , vital:41203 , Rhodes University, Cory Library for Humanities Research Cory Library Manuscript Collection MS 18 904
- Description: Exhibits G : other documents including affidavits, letters, press and other published material, police files, photographs, plans and diagrams. People involved include Col. J Jonker, Henri Fouche, Col L du Plessis, Gen A J M Joubert, Major-General B Holomisa and Lieut.-General C P van der Westhuizen. , EXHIBITS - GONIWE Gl Diagram: Die Nasionale Veiligheidsbestuurstelsel (NBVS) G2 Opsomende diagrammatiese uiteensetting van die NBVS tot met die 1985 noodtoestand G3 Declaration of destruction of classified documents/material G4. Fraser: Lessons learnt from past revolutionary wars GS Kol J Jonker: Photo album - Strand Street G6 . Memorandum of the South West Africa Bar Council G7 Jacques Pauw In the Heart of the Whore, p113 G8 Accountability in Namibia (Africa Watch) G9 Goniwe’s Cradock File (ppl - 53) Aansoek vir in tamatie (p54) Extract from file (p55 - 58) G10 Goniwe’s telephone transcripts 1985/06/21 • 1985/06/28 G11 Affidavit of Henri Fouche G12 Annexures A- F: Fouche G13 Race Relations' Survey 1983, pp608 - 609 G14 Race Relations Survey 1985 pp482 - 483 G15 Race Relations Survey 1992/ 1993 p28 G16 Record and reasons for finding: S v Hamakali G17 Faku Inquest: Docket G18 Faku Inquest: Photo’s Gl9 EP Herald: 16 December 1989 G20 Faku Inquest: Investigation Diary G21 Description: Jetta Rear Axle G22 Beskadingsverslag: Staatsvoertuig G23 Map: Scene of explosion G24 Minutes: Inspection in loco G2S Photo’s: Inspection in loco G26 Registration of Jetta G27 Back of Faku investigation docket G28 Faku docket: Name en addresse van getuies G29 Druktelegram GONIWE EXHIBITS: FILE 2 G30 Letter from Wagenaar to Col Du 'Plessis, dated 5 February 1993 G31 Letter from Wagenaar to Col Du Plessis, dated 2 March 1993 G32 McCuen mimeo G33 Joubert affidavit and CCB document G34 Original damaged Katzen documents G35 Katzen: Glossary G36 Katzen: List of names G37 G38 Letter from Col Du Plessis to commanding officer, EP Command G39 Note regarding Du Plessis’ absence G40 Luus affidavit G41 Du Plessis evidence before commission G42 Letter from Maj-Gen Holomisa to State President G43 Du Plessis statement to New Nation G44 New Nation 8 - 14 May G4S Bank account: Du Plessis G46 'Verwyder’ documents G47 Diagram: Rewo oorlog G4S Bank document: Du Plessis G49 Letter from Col Du Plessis to Cyril Ramaphosa G50 Bevelskrif: Van der Westhuizen (Pligstaat) G51 Curriculum vitae: Van der Westhuizen G52 Plan: offices of EP Command G53 Verslag deur Botha Marais dated 3 February 1985 G54 Pauw: Heart of the whore extract G55 OPGBS minutes: 23 February 1984 G56 Dictionary of military terms G57 Heitman - article (Militaria) G58 Kort kursus in - strategie vir amptenare G59 Lesing 10 G60 Minutes of PE GIS meeting: 1985-05-30 G61 New Nation 30 April - 7 May 1985 G62 The Undeclared War G63 Verplasing Nr S163373E Sersant F.Z. Koni G64 Oor- en verplasing Nr S163373E Sersant F.Z. Koni : vanaf Veiligheidstak, Cradock (BP 1801) na die Uniformtak, Cradock (BP 1801) G65 Ontlsag weens mediese ongeskiktheid : NR S163373E Konstabel F.Z. Koni G66 Memo: Verplasing : W66950H Sers G.H. Lourentz G67 Diensbeeindiging rekord Konstabel Elizabeth van Zyl G68 Mediese iname verslag G69 Intydese Persal Verslag: W A Roux G70 Oor- en verplasing : W86689T Adjudant-offisier W A Roux : vanaf Uniformtak, Cradock (BP 1801) na die Veiligheidstak, Cradock (BP 1801) G71A Besonderhede van voertuig G71B Vervanging: motorcar SAP 48549N G71C Vervanging: motorcar SAP 48549N G72 Ondersoekdagboek
- Full Text:
- Authors: Goniwe Inquest
- Subjects: Goniwe, Matthew 1946-1985 , Calata, Fort -1985 , Mkonto, Sparrow -1985 , Mhlauli, Sicelo -1985 , South Africa South African Defence Force , South African Police , Violent deaths South Africa , Inquests South Africa , Colonel Du Plessis, Lourens SADF , General Van der Westhuizen, C P SADF , Colonel Jonker, J SAP , Bozalek, Lee Legal Resources Centre, Cape Town , Makhaula, Gladdwell Cradock Residents Association (CRADORA) , Fouche, Henri , Cradock Workers Union , Holomisa, Bantu, 1955- , Joubert, A J M , Lessons learnt from past revolutionay wars by Brigadier C.A. Fraser, SM
- Language: English , Afrikaans
- Type: legal case and case notes , text
- Identifier: http://hdl.handle.net/10962/165046 , vital:41203 , Rhodes University, Cory Library for Humanities Research Cory Library Manuscript Collection MS 18 904
- Description: Exhibits G : other documents including affidavits, letters, press and other published material, police files, photographs, plans and diagrams. People involved include Col. J Jonker, Henri Fouche, Col L du Plessis, Gen A J M Joubert, Major-General B Holomisa and Lieut.-General C P van der Westhuizen. , EXHIBITS - GONIWE Gl Diagram: Die Nasionale Veiligheidsbestuurstelsel (NBVS) G2 Opsomende diagrammatiese uiteensetting van die NBVS tot met die 1985 noodtoestand G3 Declaration of destruction of classified documents/material G4. Fraser: Lessons learnt from past revolutionary wars GS Kol J Jonker: Photo album - Strand Street G6 . Memorandum of the South West Africa Bar Council G7 Jacques Pauw In the Heart of the Whore, p113 G8 Accountability in Namibia (Africa Watch) G9 Goniwe’s Cradock File (ppl - 53) Aansoek vir in tamatie (p54) Extract from file (p55 - 58) G10 Goniwe’s telephone transcripts 1985/06/21 • 1985/06/28 G11 Affidavit of Henri Fouche G12 Annexures A- F: Fouche G13 Race Relations' Survey 1983, pp608 - 609 G14 Race Relations Survey 1985 pp482 - 483 G15 Race Relations Survey 1992/ 1993 p28 G16 Record and reasons for finding: S v Hamakali G17 Faku Inquest: Docket G18 Faku Inquest: Photo’s Gl9 EP Herald: 16 December 1989 G20 Faku Inquest: Investigation Diary G21 Description: Jetta Rear Axle G22 Beskadingsverslag: Staatsvoertuig G23 Map: Scene of explosion G24 Minutes: Inspection in loco G2S Photo’s: Inspection in loco G26 Registration of Jetta G27 Back of Faku investigation docket G28 Faku docket: Name en addresse van getuies G29 Druktelegram GONIWE EXHIBITS: FILE 2 G30 Letter from Wagenaar to Col Du 'Plessis, dated 5 February 1993 G31 Letter from Wagenaar to Col Du Plessis, dated 2 March 1993 G32 McCuen mimeo G33 Joubert affidavit and CCB document G34 Original damaged Katzen documents G35 Katzen: Glossary G36 Katzen: List of names G37 G38 Letter from Col Du Plessis to commanding officer, EP Command G39 Note regarding Du Plessis’ absence G40 Luus affidavit G41 Du Plessis evidence before commission G42 Letter from Maj-Gen Holomisa to State President G43 Du Plessis statement to New Nation G44 New Nation 8 - 14 May G4S Bank account: Du Plessis G46 'Verwyder’ documents G47 Diagram: Rewo oorlog G4S Bank document: Du Plessis G49 Letter from Col Du Plessis to Cyril Ramaphosa G50 Bevelskrif: Van der Westhuizen (Pligstaat) G51 Curriculum vitae: Van der Westhuizen G52 Plan: offices of EP Command G53 Verslag deur Botha Marais dated 3 February 1985 G54 Pauw: Heart of the whore extract G55 OPGBS minutes: 23 February 1984 G56 Dictionary of military terms G57 Heitman - article (Militaria) G58 Kort kursus in - strategie vir amptenare G59 Lesing 10 G60 Minutes of PE GIS meeting: 1985-05-30 G61 New Nation 30 April - 7 May 1985 G62 The Undeclared War G63 Verplasing Nr S163373E Sersant F.Z. Koni G64 Oor- en verplasing Nr S163373E Sersant F.Z. Koni : vanaf Veiligheidstak, Cradock (BP 1801) na die Uniformtak, Cradock (BP 1801) G65 Ontlsag weens mediese ongeskiktheid : NR S163373E Konstabel F.Z. Koni G66 Memo: Verplasing : W66950H Sers G.H. Lourentz G67 Diensbeeindiging rekord Konstabel Elizabeth van Zyl G68 Mediese iname verslag G69 Intydese Persal Verslag: W A Roux G70 Oor- en verplasing : W86689T Adjudant-offisier W A Roux : vanaf Uniformtak, Cradock (BP 1801) na die Veiligheidstak, Cradock (BP 1801) G71A Besonderhede van voertuig G71B Vervanging: motorcar SAP 48549N G71C Vervanging: motorcar SAP 48549N G72 Ondersoekdagboek
- Full Text:
Statistical Analysis of the Radio-Interferometric Measurement Equation, a derived adaptive weighting scheme, and applications to LOFAR-VLBI observation of the Extended Groth Strip
- Authors: Bonnassieux, Etienne
- Date: 2019
- Subjects: Radio astronomy , Astrophysics , Astrophysics -- Instruments -- Calibration , Imaging systems in astronomy , Radio interferometers , Radio telescopes , Astronomy -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/93789 , vital:30942
- Description: J.R.R Tolkien wrote, in his Mythopoeia, that “He sees no stars who does not see them first, of living silver made that sudden burst, to flame like flowers beneath the ancient song”. In his defense of myth-making, he formulates the argument that the attribution of meaning is an act of creation - that “trees are not ‘trees’ until so named and seen” - and that this capacity for creation defines the human creature. The scientific endeavour, in this context, can be understood as a social expression of a fundamental feature of humanity, and from this endeavour flows much understanding. This thesis, one thread among many, focuses on the study of astronomical objects as seen by the radio waves they emit. What are radio waves? Electromagnetic waves were theorised by James Clerk Maxwell (Maxwell 1864) in his great theoretical contribution to modern physics, their speed matching the speed of light as measured by Ole Christensen R0mer and, later, James Bradley. It was not until Heinrich Rudolf Hertz’s 1887 experiment that these waves were measured in a laboratory, leading to the dawn of radio communications - and, later, radio astronomy. The link between radio waves and light was one of association: light is known to behave as a wave (Young double-slit experiment), with the same propagation speed as electromagnetic radiation. Light “proper” is also known to exist beyond the optical regime: Herschel’s experiment shows that when diffracted through a prism, sunlight warms even those parts of a desk which are not observed to be lit (first evidence of infrared light). The link between optical light and unseen electromagnetic radiation is then an easy step to make, and one confirmed through countless technological applications (e.g. optical fiber to name but one). And as soon as this link is established, a question immediately comes to the mind of the astronomer: what does the sky, our Universe, look like to the radio “eye”? Radio astronomy has a short but storied history: from Karl Jansky’s serendipitous observation of the centre of the Milky Way, which outshines our Sun in the radio regime, in 1933, to Grote Reber’s hand-built back-yard radio antenna in 1937, which successfully detected radio emission from the Milky Way itself, to such monumental projects as the Square Kilometer Array and its multiple pathfinders, it has led to countless discoveries and the opening of a truly new window on the Universe. The work presented in this thesis is a contribution to this discipline - the culmination of three years of study, which is a rather short time to get a firm grasp of radio interferometry both in theory and in practice. The need for robust, automated methods - which are improving daily, thanks to the tireless labour of the scientists in the field - is becoming ever stronger as the SKA approaches, looming large on the horizon; but even today, in the precursor era of LOFAR, MeerKAT and other pathfinders, it is keenly felt. When I started my doctorate, the sheer scale of the task at hand felt overwhelming - to actually be able to contribute to its resolution seemed daunting indeed! Thankfully, as the saying goes, no society sets for itself material goals which it cannot achieve. This thesis took place at an exciting time for radio interferometry: at the start of my doctorate, the LOFAR international stations were - to my knowledge - only beginning to be used, and even then, only tentatively; MeerKAT had not yet shown its first light; the techniques used throughout my work were still being developed. At the time of writing, great strides have been made. One of the greatest technical challenges of LOFAR - imaging using the international stations - is starting to become reality. This technical challenge is the key problem that this thesis set out to address. While we only achieved partial success so far, it is a testament to the difficulty of the task that it is not yet truly resolved. One of the major results of this thesis is a model of a bright resolved source near a famous extragalactic field: properly modeling this source not only allows the use of international LOFAR stations, but also grants deeper access to the extragalactic field itself, which is otherwise polluted by the 3C source’s sidelobes. This result was only achieved thanks to the other major result of this thesis: the development of a theoretical framework with which to better understand the effect of calibration errors on images made from interferometric data, and an algorithm to strongly mitigate them. The structure of this manuscript is as follows: we begin with an introduction to radio interferometry, LOFAR, and the emission mechanisms which dominate for our field of interest. These introductions are primarily intended to give a brief overview of the technical aspects of the data reduced in this thesis. We follow with an overview of the Measurement Equation formalism, which underpins our theoretical work. This is the keystone of this thesis. We then show the theoretical work that was developed as part of the research work done during the doctorate - which was published in Astronomy & Astrophysics. Its practical application - a quality-based weighting scheme - is used throughout our data reduction. This data reduction is the next topic of this thesis: we contextualise the scientific interest of the data we reduce, and explain both the methods and the results we achieve.
- Full Text:
- Date Issued: 2019
- Authors: Bonnassieux, Etienne
- Date: 2019
- Subjects: Radio astronomy , Astrophysics , Astrophysics -- Instruments -- Calibration , Imaging systems in astronomy , Radio interferometers , Radio telescopes , Astronomy -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/93789 , vital:30942
- Description: J.R.R Tolkien wrote, in his Mythopoeia, that “He sees no stars who does not see them first, of living silver made that sudden burst, to flame like flowers beneath the ancient song”. In his defense of myth-making, he formulates the argument that the attribution of meaning is an act of creation - that “trees are not ‘trees’ until so named and seen” - and that this capacity for creation defines the human creature. The scientific endeavour, in this context, can be understood as a social expression of a fundamental feature of humanity, and from this endeavour flows much understanding. This thesis, one thread among many, focuses on the study of astronomical objects as seen by the radio waves they emit. What are radio waves? Electromagnetic waves were theorised by James Clerk Maxwell (Maxwell 1864) in his great theoretical contribution to modern physics, their speed matching the speed of light as measured by Ole Christensen R0mer and, later, James Bradley. It was not until Heinrich Rudolf Hertz’s 1887 experiment that these waves were measured in a laboratory, leading to the dawn of radio communications - and, later, radio astronomy. The link between radio waves and light was one of association: light is known to behave as a wave (Young double-slit experiment), with the same propagation speed as electromagnetic radiation. Light “proper” is also known to exist beyond the optical regime: Herschel’s experiment shows that when diffracted through a prism, sunlight warms even those parts of a desk which are not observed to be lit (first evidence of infrared light). The link between optical light and unseen electromagnetic radiation is then an easy step to make, and one confirmed through countless technological applications (e.g. optical fiber to name but one). And as soon as this link is established, a question immediately comes to the mind of the astronomer: what does the sky, our Universe, look like to the radio “eye”? Radio astronomy has a short but storied history: from Karl Jansky’s serendipitous observation of the centre of the Milky Way, which outshines our Sun in the radio regime, in 1933, to Grote Reber’s hand-built back-yard radio antenna in 1937, which successfully detected radio emission from the Milky Way itself, to such monumental projects as the Square Kilometer Array and its multiple pathfinders, it has led to countless discoveries and the opening of a truly new window on the Universe. The work presented in this thesis is a contribution to this discipline - the culmination of three years of study, which is a rather short time to get a firm grasp of radio interferometry both in theory and in practice. The need for robust, automated methods - which are improving daily, thanks to the tireless labour of the scientists in the field - is becoming ever stronger as the SKA approaches, looming large on the horizon; but even today, in the precursor era of LOFAR, MeerKAT and other pathfinders, it is keenly felt. When I started my doctorate, the sheer scale of the task at hand felt overwhelming - to actually be able to contribute to its resolution seemed daunting indeed! Thankfully, as the saying goes, no society sets for itself material goals which it cannot achieve. This thesis took place at an exciting time for radio interferometry: at the start of my doctorate, the LOFAR international stations were - to my knowledge - only beginning to be used, and even then, only tentatively; MeerKAT had not yet shown its first light; the techniques used throughout my work were still being developed. At the time of writing, great strides have been made. One of the greatest technical challenges of LOFAR - imaging using the international stations - is starting to become reality. This technical challenge is the key problem that this thesis set out to address. While we only achieved partial success so far, it is a testament to the difficulty of the task that it is not yet truly resolved. One of the major results of this thesis is a model of a bright resolved source near a famous extragalactic field: properly modeling this source not only allows the use of international LOFAR stations, but also grants deeper access to the extragalactic field itself, which is otherwise polluted by the 3C source’s sidelobes. This result was only achieved thanks to the other major result of this thesis: the development of a theoretical framework with which to better understand the effect of calibration errors on images made from interferometric data, and an algorithm to strongly mitigate them. The structure of this manuscript is as follows: we begin with an introduction to radio interferometry, LOFAR, and the emission mechanisms which dominate for our field of interest. These introductions are primarily intended to give a brief overview of the technical aspects of the data reduced in this thesis. We follow with an overview of the Measurement Equation formalism, which underpins our theoretical work. This is the keystone of this thesis. We then show the theoretical work that was developed as part of the research work done during the doctorate - which was published in Astronomy & Astrophysics. Its practical application - a quality-based weighting scheme - is used throughout our data reduction. This data reduction is the next topic of this thesis: we contextualise the scientific interest of the data we reduce, and explain both the methods and the results we achieve.
- Full Text:
- Date Issued: 2019