Neural network-based ionospheric modelling over the South African region
- McKinnell, Lee-Anne, Poole, Allon W V
- Authors: McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6795 , http://hdl.handle.net/10962/d1003839
- Description: During the past decade, South African scientists have pioneered research in the field of ionospheric modelling using the technique of neural networks (NNs). Global ionospheric models have always been insufficient for the South African region owing to an historical paucity of available data. Within the past 10 years, however, three new ionospheric sounders have been installed locally and are operating continuously. These sounders are located at Grahamstown (33.3°S, 26.5°E), Louisvale (28.5°S, 21.2°E) and Madimbo (22.4°S, 30.9°E). The addition of a modern sounder at Grahamstown enlarged the ionospheric database for this station to 30 years, making this archive a considerable asset for ionospheric research. Quality control and online availability of the data has also added to its attraction. An important requirement for empirical modelling, but especially for employing NNs, is a large database describing the history of the relationship between the ionosphere and the geophysical parameters that define its behaviour. This review describes the path of South African ionospheric modelling over the past 10 years, the role of NNs in this development, the international collaborations that have arisen from this, and the future of ionospheric modelling in South Africa.
- Full Text:
- Authors: McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6795 , http://hdl.handle.net/10962/d1003839
- Description: During the past decade, South African scientists have pioneered research in the field of ionospheric modelling using the technique of neural networks (NNs). Global ionospheric models have always been insufficient for the South African region owing to an historical paucity of available data. Within the past 10 years, however, three new ionospheric sounders have been installed locally and are operating continuously. These sounders are located at Grahamstown (33.3°S, 26.5°E), Louisvale (28.5°S, 21.2°E) and Madimbo (22.4°S, 30.9°E). The addition of a modern sounder at Grahamstown enlarged the ionospheric database for this station to 30 years, making this archive a considerable asset for ionospheric research. Quality control and online availability of the data has also added to its attraction. An important requirement for empirical modelling, but especially for employing NNs, is a large database describing the history of the relationship between the ionosphere and the geophysical parameters that define its behaviour. This review describes the path of South African ionospheric modelling over the past 10 years, the role of NNs in this development, the international collaborations that have arisen from this, and the future of ionospheric modelling in South Africa.
- Full Text:
Parasitoids associated with the diamondback moth, Plutella xylostella (L.), in the Eastern Cape, South Africa
- Smith, Tamara J, Villet, Martin H
- Authors: Smith, Tamara J , Villet, Martin H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , conference
- Identifier: http://hdl.handle.net/10962/442795 , vital:74034 , ISBN , https://www.cabidigitallibrary.org/doi/full/10.5555/20093098381
- Description: Seasonal fluctuations of diamondback moth and its hymenopteran parasitoids were recorded weekly from April 1997 to November 1999 at four cabbage sites in the Grahamstown area of the Eastern Cape, South Africa. Two sites were commercial farms with active spraying programmes; the others were unsprayed. Infestation levels were highest during spring (September to November) and autumn (March to May), where 100% infestation of plants was reached at times. The highest infestation was found during the spring months, where 12 larvae/plant were found at the unsprayed sites and between 6 and 10 larvae at the sprayed sites. At the unsprayed sites abundance of diamondback moth larvae and parasitoids was high during 1997, but much lower during 1998 and 1999, indicating possible control by the parasitoids. Nine species of parasitoid were recorded from diamondback moth during this period and four (Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae), Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae), Diadromus collaris Gravenhorst (Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae)) showed potential as biological control agents. The highest rate of parasitism was found from mid-autumn to the beginning of winter (April to June) and from mid-spring to the beginning of summer (October to December). Percent parasitism varied throughout the year, ranging between 10% and 80%. Parasitism of 100% was observed when moth numbers were low. Different species of parasitoids were found to be dominant at different times of the year.
- Full Text:
- Authors: Smith, Tamara J , Villet, Martin H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , conference
- Identifier: http://hdl.handle.net/10962/442795 , vital:74034 , ISBN , https://www.cabidigitallibrary.org/doi/full/10.5555/20093098381
- Description: Seasonal fluctuations of diamondback moth and its hymenopteran parasitoids were recorded weekly from April 1997 to November 1999 at four cabbage sites in the Grahamstown area of the Eastern Cape, South Africa. Two sites were commercial farms with active spraying programmes; the others were unsprayed. Infestation levels were highest during spring (September to November) and autumn (March to May), where 100% infestation of plants was reached at times. The highest infestation was found during the spring months, where 12 larvae/plant were found at the unsprayed sites and between 6 and 10 larvae at the sprayed sites. At the unsprayed sites abundance of diamondback moth larvae and parasitoids was high during 1997, but much lower during 1998 and 1999, indicating possible control by the parasitoids. Nine species of parasitoid were recorded from diamondback moth during this period and four (Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae), Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae), Diadromus collaris Gravenhorst (Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae)) showed potential as biological control agents. The highest rate of parasitism was found from mid-autumn to the beginning of winter (April to June) and from mid-spring to the beginning of summer (October to December). Percent parasitism varied throughout the year, ranging between 10% and 80%. Parasitism of 100% was observed when moth numbers were low. Different species of parasitoids were found to be dominant at different times of the year.
- Full Text:
Rare earth element geochemistry of the Insizwa lobe of the Mount Ayliff Complex, Eastern Cape, South Africa
- Authors: Marsh, Julian S
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6736 , http://hdl.handle.net/10962/d1007548
- Description: New rare earth element (REE) data from all lithologies of the Insizwa lobe, Mount Ayliff Complex, are presented. On the basis of size and type of Eu anomaly, the geochemical subdivision of the complex as previously described is sustained and, additionally, the Top Gabbronorite of the Central Zone is shown to have formed from a magma that was compositionally distinct from other Central Zone magmas. The Basal Zone crystallized from magmas with large negative Eu anomalies probably acquired through crustal contamination. Previously recognized compositional heterogeneity in the contact rocks is also a feature of the REE. Overall, the Insizwa magmas had higher La/Sm ratios and, to a lesser extent, higher Gd/Yb ratios than Karoo basalts and appear to have no representatives in the basalt lava sequence of Lesotho.
- Full Text:
- Authors: Marsh, Julian S
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6736 , http://hdl.handle.net/10962/d1007548
- Description: New rare earth element (REE) data from all lithologies of the Insizwa lobe, Mount Ayliff Complex, are presented. On the basis of size and type of Eu anomaly, the geochemical subdivision of the complex as previously described is sustained and, additionally, the Top Gabbronorite of the Central Zone is shown to have formed from a magma that was compositionally distinct from other Central Zone magmas. The Basal Zone crystallized from magmas with large negative Eu anomalies probably acquired through crustal contamination. Previously recognized compositional heterogeneity in the contact rocks is also a feature of the REE. Overall, the Insizwa magmas had higher La/Sm ratios and, to a lesser extent, higher Gd/Yb ratios than Karoo basalts and appear to have no representatives in the basalt lava sequence of Lesotho.
- Full Text:
The general election in Lesotho, May 2002: adapting to MMP
- Fox, Roddy C, Southall, Roger J
- Authors: Fox, Roddy C , Southall, Roger J
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6680 , http://hdl.handle.net/10962/d1006673
- Description: Voters in the small southern African kingdom of Lesotho went to the polls on 25 May 2002, in the third general election since the country returned to democracy following a long period of civilian dictatorship (1970–1986) and military rule (1986–1993). Voting in all Lesotho’s general elections has usually gone smoothly, yet in every case prior to 2002 the results have been challenged, with varying severity, by the losing parties (Weisfelder, 1999). This occurred most notably in 1970, when the ruling Basotho National Party (BNP) lost the election but overrode the result, and subsequently in 1998, when the BNP—then in opposition—was at the core of an alliance of electoral losers; in the months that followed, and with the quiet support of the security forces, the capital was so paralysed that the government called for external assistance to restore order. The result was military intervention by South Africa and Botswana (who acted on behalf of the Southern African Development Community, SADC), the restoration of power to the Lesotho Congress for Democracy (LCD), and an extended period when, backed by South African muscle, long overdue reforms of the military and police were implemented. These reforms were matched by negotiations between the parties about adopting a new electoral system. The outcome moved Lesotho away from the first-past-the-post system inherited from Britain at independence (which in 1993 and 1998 had resulted in highly imbalanced results favouring the winning party) towards a Mixed Member Proportional (MMP) system. Lesotho became the first country in Africa to adopt MMP at a time when discussion of electoral system change was becoming widespread throughout the continent. The issue in Lesotho in 2002 was not merely whether MMP would provide greater electoral legitimacy and political stability; subsequent events have provided a resounding ‘Yes’ (Elklit, 2002 and Southall, 2003). But there were questions about the practicality of the new system and whether voters would understand it. Was it possible to explain a new voting system to an electorate in one of Africa’s poorest countries? The main focus of this Note is to demonstrate that voters can adapt to electoral system change. Thus, it throws doubt on arguments that electoral reforms in Africa should be avoided due to a lack of sophistication among poor and largely uneducated voters. Electors in Lesotho appeared to have no great difficulty in understanding the broad principles of the new electoral system, even if the detailed mechanics of ‘mixed’ voting systems may have been beyond them.
- Full Text:
- Authors: Fox, Roddy C , Southall, Roger J
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6680 , http://hdl.handle.net/10962/d1006673
- Description: Voters in the small southern African kingdom of Lesotho went to the polls on 25 May 2002, in the third general election since the country returned to democracy following a long period of civilian dictatorship (1970–1986) and military rule (1986–1993). Voting in all Lesotho’s general elections has usually gone smoothly, yet in every case prior to 2002 the results have been challenged, with varying severity, by the losing parties (Weisfelder, 1999). This occurred most notably in 1970, when the ruling Basotho National Party (BNP) lost the election but overrode the result, and subsequently in 1998, when the BNP—then in opposition—was at the core of an alliance of electoral losers; in the months that followed, and with the quiet support of the security forces, the capital was so paralysed that the government called for external assistance to restore order. The result was military intervention by South Africa and Botswana (who acted on behalf of the Southern African Development Community, SADC), the restoration of power to the Lesotho Congress for Democracy (LCD), and an extended period when, backed by South African muscle, long overdue reforms of the military and police were implemented. These reforms were matched by negotiations between the parties about adopting a new electoral system. The outcome moved Lesotho away from the first-past-the-post system inherited from Britain at independence (which in 1993 and 1998 had resulted in highly imbalanced results favouring the winning party) towards a Mixed Member Proportional (MMP) system. Lesotho became the first country in Africa to adopt MMP at a time when discussion of electoral system change was becoming widespread throughout the continent. The issue in Lesotho in 2002 was not merely whether MMP would provide greater electoral legitimacy and political stability; subsequent events have provided a resounding ‘Yes’ (Elklit, 2002 and Southall, 2003). But there were questions about the practicality of the new system and whether voters would understand it. Was it possible to explain a new voting system to an electorate in one of Africa’s poorest countries? The main focus of this Note is to demonstrate that voters can adapt to electoral system change. Thus, it throws doubt on arguments that electoral reforms in Africa should be avoided due to a lack of sophistication among poor and largely uneducated voters. Electors in Lesotho appeared to have no great difficulty in understanding the broad principles of the new electoral system, even if the detailed mechanics of ‘mixed’ voting systems may have been beyond them.
- Full Text:
The kaolinitic clay deposits on Beaconsfield, north of Grahamstown
- Jacob, Roger E, Mitha, Vindina R, MacPherson, D
- Authors: Jacob, Roger E , Mitha, Vindina R , MacPherson, D
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6734 , http://hdl.handle.net/10962/d1007544
- Description: The Grahamstown clay deposits occur below the Grahamstown Formation silcrete, which forms a remnant of an extensive peneplain that developed on the African erosion surface during the Cretaceous–Tertiary period. This paper provides new data on the distribution of the kaolinitic clay deposits in the Beaconsfield area north of Grahamstown. These data include 23 borehole profiles through the deposits, and the chemistry and mineralogy of the clays. Relatively little information is available on this part of the peneplain. It was found that the thickness of the kaolin horizon varies considerably, but reaches 35m in places. It generally occurs under a silcrete cover, which attains a thickness of 8 m in places. Lithological logs enable direct comparison across the Beaconsfield area. The clays are developed in both the Witteberg Group shale and Dwyka Group tillite. The contact between the clay and underlying bedrock is gradational and relatively uneven. Major-element X-ray fluorescence analyses revealed that there is chemical variation, both vertically and laterally. Al2O3 content is generally near 20%, but may reach 29%. SiO2 content varies between 55 and 70+%. SiO2 contents are highest in the silcretes occurring just below soil level. Fe2O3 is high locally in the top part of the profile. K2O and Na2O are generally low, but increase towards the unweathered bedrock as the primary feldspar content increases. These compositional variations are compatible with residual concentrations of kaolinitic clays through deep weathering below the former African erosion surface.
- Full Text:
- Authors: Jacob, Roger E , Mitha, Vindina R , MacPherson, D
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6734 , http://hdl.handle.net/10962/d1007544
- Description: The Grahamstown clay deposits occur below the Grahamstown Formation silcrete, which forms a remnant of an extensive peneplain that developed on the African erosion surface during the Cretaceous–Tertiary period. This paper provides new data on the distribution of the kaolinitic clay deposits in the Beaconsfield area north of Grahamstown. These data include 23 borehole profiles through the deposits, and the chemistry and mineralogy of the clays. Relatively little information is available on this part of the peneplain. It was found that the thickness of the kaolin horizon varies considerably, but reaches 35m in places. It generally occurs under a silcrete cover, which attains a thickness of 8 m in places. Lithological logs enable direct comparison across the Beaconsfield area. The clays are developed in both the Witteberg Group shale and Dwyka Group tillite. The contact between the clay and underlying bedrock is gradational and relatively uneven. Major-element X-ray fluorescence analyses revealed that there is chemical variation, both vertically and laterally. Al2O3 content is generally near 20%, but may reach 29%. SiO2 content varies between 55 and 70+%. SiO2 contents are highest in the silcretes occurring just below soil level. Fe2O3 is high locally in the top part of the profile. K2O and Na2O are generally low, but increase towards the unweathered bedrock as the primary feldspar content increases. These compositional variations are compatible with residual concentrations of kaolinitic clays through deep weathering below the former African erosion surface.
- Full Text:
The microstructure of plasmodesmata in internodal stem tissue of the Saccharum hybrid var. NCo376 : evidence for an apoplasmic loading pathway
- Botha, Christiaan E J, Cross, Robin H M, Gerber, Jacques
- Authors: Botha, Christiaan E J , Cross, Robin H M , Gerber, Jacques
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6494 , http://hdl.handle.net/10962/d1004487
- Description: The distribution, structure and functional state of plasmodesmata were investigated to gain a clearer understanding of the sucrose transport pathway to the storage parenchyma cells in stem tissue in Saccharum officinarum var. NCo376. Evidence from structural studies on sugarcane stems by electron microscopy indicated that there are numerous plasmodesmata from the vascular bundles through to the storage parenchyma cells in mature stem tissue. Our studies, supported by fluorescence microscopy and iontophoresis, indicate that there are functional plasmodesmata in the phloemunloading pathway from transport phloem tissue to the bundle sheath in Saccharum, which could support symplasmic transport; plasmodesmata outside of the sheath cells in the storage parenchyma appear to be constricted by sphincter-like structures within their neck regions. Staining with Aniline Blue revealed evidence of large callose deposits, which co-localized with plasmodesmatal aggregates in the walls of the storage parenchyma cells. This suggests that the sucrose transport into, and accumulation by, storage parenchyma of mature stem tissue is under apoplasmic control.
- Full Text:
- Authors: Botha, Christiaan E J , Cross, Robin H M , Gerber, Jacques
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6494 , http://hdl.handle.net/10962/d1004487
- Description: The distribution, structure and functional state of plasmodesmata were investigated to gain a clearer understanding of the sucrose transport pathway to the storage parenchyma cells in stem tissue in Saccharum officinarum var. NCo376. Evidence from structural studies on sugarcane stems by electron microscopy indicated that there are numerous plasmodesmata from the vascular bundles through to the storage parenchyma cells in mature stem tissue. Our studies, supported by fluorescence microscopy and iontophoresis, indicate that there are functional plasmodesmata in the phloemunloading pathway from transport phloem tissue to the bundle sheath in Saccharum, which could support symplasmic transport; plasmodesmata outside of the sheath cells in the storage parenchyma appear to be constricted by sphincter-like structures within their neck regions. Staining with Aniline Blue revealed evidence of large callose deposits, which co-localized with plasmodesmatal aggregates in the walls of the storage parenchyma cells. This suggests that the sucrose transport into, and accumulation by, storage parenchyma of mature stem tissue is under apoplasmic control.
- Full Text:
Three decades of hydrological modelling research in South Africa
- Authors: Hughes, Denis A
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:7072 , http://hdl.handle.net/10962/d1009526
- Description: This paper presents a review of the research undertaken in the field of hydrological modelling over roughly the last three decades, concentrating primarily on South African work in an international context. The focus is on deterministic, rainfall-runoff models and addresses issues related to model design as well as to the application of models in practice. I provide a brief description of what hydrological models are and what they are used for and discuss also the following issues: • Developments in understanding hydrological process and the extent to which these have filtered down into models. • Model calibration and parameter estimation. • Trends in data availability and how these have affected model development. • Trends in computer technology and their impacts on model development. I suggest that there have been substantial developments in the science and practice of hydrological modelling, but that there remain many problems that need to be addressed to improve the ability of models to contribute to the solution of problems of water resource management. Southern African scientists have contributed to the body of knowledge on hydrological modelling, despite the limited resources available compared to resources elsewhere. Internationally, the focus has not always been on the practical issues of model application and has commonly tended towards the more theoretical and mathematical issues of model calibration. This is not a trend that has found much favour in southern Africa (particularly amongst research funding agencies), where there are many problems of water resource management that have the potential to be resolved with existing models, applied in an appropriate way. The paper concludes by suggesting that further research needs to focus on the integration of the best in international developments with the tried and tested models that have been developed locally. The context of this research should be the search for more reliable estimations of water resource availability.
- Full Text:
- Authors: Hughes, Denis A
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:7072 , http://hdl.handle.net/10962/d1009526
- Description: This paper presents a review of the research undertaken in the field of hydrological modelling over roughly the last three decades, concentrating primarily on South African work in an international context. The focus is on deterministic, rainfall-runoff models and addresses issues related to model design as well as to the application of models in practice. I provide a brief description of what hydrological models are and what they are used for and discuss also the following issues: • Developments in understanding hydrological process and the extent to which these have filtered down into models. • Model calibration and parameter estimation. • Trends in data availability and how these have affected model development. • Trends in computer technology and their impacts on model development. I suggest that there have been substantial developments in the science and practice of hydrological modelling, but that there remain many problems that need to be addressed to improve the ability of models to contribute to the solution of problems of water resource management. Southern African scientists have contributed to the body of knowledge on hydrological modelling, despite the limited resources available compared to resources elsewhere. Internationally, the focus has not always been on the practical issues of model application and has commonly tended towards the more theoretical and mathematical issues of model calibration. This is not a trend that has found much favour in southern Africa (particularly amongst research funding agencies), where there are many problems of water resource management that have the potential to be resolved with existing models, applied in an appropriate way. The paper concludes by suggesting that further research needs to focus on the integration of the best in international developments with the tried and tested models that have been developed locally. The context of this research should be the search for more reliable estimations of water resource availability.
- Full Text:
Cleaning fouled membranes using sludge enzymes
- Melamane, Xolisa L, Pletschke, Brett I, Leukes, Winston D, Whiteley, Chris G
- Authors: Melamane, Xolisa L , Pletschke, Brett I , Leukes, Winston D , Whiteley, Chris G
- Date: 2003
- Language: English
- Type: text
- Identifier: vital:6480 , http://hdl.handle.net/10962/d1006242
- Description: Maintenance of membrane performance requires inevitable cleaning or "defouling" of fouled membranes. Membrane cleaning using sludge enzymes, was investigated by first characterising ostrich abattoir effluent for potential foulants, such as lipids, proteins and polysaccharides. Static fouling of polysulphone membranes using abattoir effluent was also performed. Biochemical analysis was performed using quantitative and qualitative methods for detection of proteins on fouled and defouled membranes. The ability of sulphidogenic proteases to remove proteins adsorbed on polysulphone membranes and capillary ultrafiltration membranes after static fouling, and ability to restore permeate fluxes and transmembrane pressure after dynamic fouling was also investigated. Permeate volumes were analysed for protein and amino acids concentrations. The abattoir effluent contained 553 μg/ml of lipid, 301 μg/ml of protein, 141 μg/ml of total carbohydrate, and 0.63 μg/ml of total reducing sugars. Static fouled membranes removed 23.4percent of proteins. Defouling of dynamically fouled capillary ultrafiltration membranes using sulphidogenic proteases was successful at pH 10, 37°C, within 1 h. Sulphidogenic protease activity was 2.1 U/ml and Flux Recovery (FR percent) was 64 percent.
- Full Text:
- Authors: Melamane, Xolisa L , Pletschke, Brett I , Leukes, Winston D , Whiteley, Chris G
- Date: 2003
- Language: English
- Type: text
- Identifier: vital:6480 , http://hdl.handle.net/10962/d1006242
- Description: Maintenance of membrane performance requires inevitable cleaning or "defouling" of fouled membranes. Membrane cleaning using sludge enzymes, was investigated by first characterising ostrich abattoir effluent for potential foulants, such as lipids, proteins and polysaccharides. Static fouling of polysulphone membranes using abattoir effluent was also performed. Biochemical analysis was performed using quantitative and qualitative methods for detection of proteins on fouled and defouled membranes. The ability of sulphidogenic proteases to remove proteins adsorbed on polysulphone membranes and capillary ultrafiltration membranes after static fouling, and ability to restore permeate fluxes and transmembrane pressure after dynamic fouling was also investigated. Permeate volumes were analysed for protein and amino acids concentrations. The abattoir effluent contained 553 μg/ml of lipid, 301 μg/ml of protein, 141 μg/ml of total carbohydrate, and 0.63 μg/ml of total reducing sugars. Static fouled membranes removed 23.4percent of proteins. Defouling of dynamically fouled capillary ultrafiltration membranes using sulphidogenic proteases was successful at pH 10, 37°C, within 1 h. Sulphidogenic protease activity was 2.1 U/ml and Flux Recovery (FR percent) was 64 percent.
- Full Text:
Education, ethics and values : A response to Peter Blaze Corcoran’s keynote address, EEASA 2003
- Authors: van Harmelen, Ursula
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6099 , http://hdl.handle.net/10962/d1008663
- Description: This paper is written in response to the Keynote Adress on the Earth Charter presented by Peter Blaze Corcoran at the EEASA 2003 Conference in Namibia. It draws attention to the significance of ethical debates in education and emphasises the need for careful attention to the way in which educators approach values education. In particular the paper considers the Earth Charter critically, and notes that while there is much value in the principles of the Earth Charter for guiding educational practice, educators should also consider some of the dilemmas of simply appropriating univeral ethical frameworks to guide practice.
- Full Text:
- Authors: van Harmelen, Ursula
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6099 , http://hdl.handle.net/10962/d1008663
- Description: This paper is written in response to the Keynote Adress on the Earth Charter presented by Peter Blaze Corcoran at the EEASA 2003 Conference in Namibia. It draws attention to the significance of ethical debates in education and emphasises the need for careful attention to the way in which educators approach values education. In particular the paper considers the Earth Charter critically, and notes that while there is much value in the principles of the Earth Charter for guiding educational practice, educators should also consider some of the dilemmas of simply appropriating univeral ethical frameworks to guide practice.
- Full Text:
Foam drug delivery in dermatology: beyond the scalp
- Purdon, Carryn H, Haigh, John M, Surber, Christian, Smith, Eric W
- Authors: Purdon, Carryn H , Haigh, John M , Surber, Christian , Smith, Eric W
- Date: 2003
- Subjects: Adis International Limited , Drug delivery systems , Skin disorders
- Language: English
- Type: text , Article
- Identifier: vital:6418 , http://hdl.handle.net/10962/d1006541
- Description: Consumers of topical formulations apply a wide spectrum of preparations, both cosmetic and dermatological, to their healthy or diseased skin. These formulations range in physicochemical nature from solid through semisolid to liquid. Pharmaceutical foams are pressurized dosage forms containing one or more active ingredients that, upon valve actuation, emit a fine dispersion of liquid and/or solid materials in a gaseous medium. Foam formulations are generally easier to apply, are less dense, and spread more easily than other topical dosage forms. Foams may be formulated in various ways to provide emollient or drying functions to the skin, depending on the formulation constituents. Therefore, this delivery technology should be a useful addition to the spectrum of formulations available for topical use; however, as yet, only a few are commercially available. Probably the most convincing argument for the use of foams is ease of use by the patient, and consumer acceptance. Most foam dosage forms used in dermatology to date have incorporated corticosteroids, although some products have also been used to deliver antiseptics, antifungal agents, anti-inflammatory agents, local anesthetic agents, skin emollients, and protectants. Although there is no clinical evidence that foam formulations are currently superior to other conventional delivery vehicles, these formulations have a clear application advantage and with continued developments in the science of supersaturation technology, it seems certain that foam delivery systems will retain their place in the dermatological and cosmetic armamentarium.
- Full Text:
- Authors: Purdon, Carryn H , Haigh, John M , Surber, Christian , Smith, Eric W
- Date: 2003
- Subjects: Adis International Limited , Drug delivery systems , Skin disorders
- Language: English
- Type: text , Article
- Identifier: vital:6418 , http://hdl.handle.net/10962/d1006541
- Description: Consumers of topical formulations apply a wide spectrum of preparations, both cosmetic and dermatological, to their healthy or diseased skin. These formulations range in physicochemical nature from solid through semisolid to liquid. Pharmaceutical foams are pressurized dosage forms containing one or more active ingredients that, upon valve actuation, emit a fine dispersion of liquid and/or solid materials in a gaseous medium. Foam formulations are generally easier to apply, are less dense, and spread more easily than other topical dosage forms. Foams may be formulated in various ways to provide emollient or drying functions to the skin, depending on the formulation constituents. Therefore, this delivery technology should be a useful addition to the spectrum of formulations available for topical use; however, as yet, only a few are commercially available. Probably the most convincing argument for the use of foams is ease of use by the patient, and consumer acceptance. Most foam dosage forms used in dermatology to date have incorporated corticosteroids, although some products have also been used to deliver antiseptics, antifungal agents, anti-inflammatory agents, local anesthetic agents, skin emollients, and protectants. Although there is no clinical evidence that foam formulations are currently superior to other conventional delivery vehicles, these formulations have a clear application advantage and with continued developments in the science of supersaturation technology, it seems certain that foam delivery systems will retain their place in the dermatological and cosmetic armamentarium.
- Full Text:
Implementing Location Services in the Location-Transparent, Distributed Environment of the Internet
- Clayton, Peter G, Preston, Michael, Wells, George C
- Authors: Clayton, Peter G , Preston, Michael , Wells, George C
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430467 , vital:72693 , https://link.springer.com/book/10.1007/b13582?page=1#toc
- Description: This volume contains the papers presented at the 5th International Workshop on Advanced Parallel Processing Technologies, APPT 2003. This series of workshops is designed to strengthen the cooperation between the German and Chinese institutions active in the area of these technologies. It has continued to grow, providing an excellent forum for reporting advances in parallel processing technologies. The 5th workshop itself addressed the entire gamut of related topics, ranging from the architectural aspects of parallel computer hardware and system software to the applied technologies for novel applica-tions. For this workshop, we received over 191 full submissions from researchers all over the world. All the papers were peer-reviewed in depth and qualitatively graded on their relevance, originality, signi?cance, presentation, and the overall appropriateness for their acceptance. Any concerns raised were discussed in the program com-mittee. The organizing committee did an excellent job in selecting 78 papers (Among them, 21 were short ones) for presentation. In short, the papers included here represent the forefront of research from China, Germany, and the other countries.
- Full Text:
- Authors: Clayton, Peter G , Preston, Michael , Wells, George C
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430467 , vital:72693 , https://link.springer.com/book/10.1007/b13582?page=1#toc
- Description: This volume contains the papers presented at the 5th International Workshop on Advanced Parallel Processing Technologies, APPT 2003. This series of workshops is designed to strengthen the cooperation between the German and Chinese institutions active in the area of these technologies. It has continued to grow, providing an excellent forum for reporting advances in parallel processing technologies. The 5th workshop itself addressed the entire gamut of related topics, ranging from the architectural aspects of parallel computer hardware and system software to the applied technologies for novel applica-tions. For this workshop, we received over 191 full submissions from researchers all over the world. All the papers were peer-reviewed in depth and qualitatively graded on their relevance, originality, signi?cance, presentation, and the overall appropriateness for their acceptance. Any concerns raised were discussed in the program com-mittee. The organizing committee did an excellent job in selecting 78 papers (Among them, 21 were short ones) for presentation. In short, the papers included here represent the forefront of research from China, Germany, and the other countries.
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Introduction [to the book "Scatter the Shrilling Bones" by Sithembele Isaac Xhegwana]
- Authors: Wright, Laurence
- Date: 2003
- Language: English
- Type: text , article
- Identifier: vital:7056 , http://hdl.handle.net/10962/d1007417
- Description: preprint , Scatter the Shrilling Bones by Sithembele Xhegwana comprises an ordered sequence of poems that conveys a journey both literal and spiritual. Revisitation is the organizing principle of the collection – the return to rural sources and origins by a consciousness estranged and illumined by modernity (cf. ‘The Return’). Underlying the collection is the theme of the night journey, whose archetype in western culture is Odysseus’ descent to the underworld – a pattern identified as such in the concluding essay ‘Starting from my Place: Notes on an Aesthetic’. The underworld here is literally the return to the home territory – a journey from Cape Town to the rural Eastern Cape – but also a revisiting of the mental world of traditional Africa: ‘Here at home, here all guilt begins’ (‘Homecoming’). The return journey is haunted by nightmare memories of mental illness, the schizophrenic episodes accompanying (or occasioned by?) the poet’s initial encounters with modernity. This illness is represented as both pathological and cultural – a price paid for challenging and rejecting the old certainties while grappling with new assumptions: “He undermines the ancestors, That’s why he suffers. Let him.” (‘To Himself’)
- Full Text:
- Authors: Wright, Laurence
- Date: 2003
- Language: English
- Type: text , article
- Identifier: vital:7056 , http://hdl.handle.net/10962/d1007417
- Description: preprint , Scatter the Shrilling Bones by Sithembele Xhegwana comprises an ordered sequence of poems that conveys a journey both literal and spiritual. Revisitation is the organizing principle of the collection – the return to rural sources and origins by a consciousness estranged and illumined by modernity (cf. ‘The Return’). Underlying the collection is the theme of the night journey, whose archetype in western culture is Odysseus’ descent to the underworld – a pattern identified as such in the concluding essay ‘Starting from my Place: Notes on an Aesthetic’. The underworld here is literally the return to the home territory – a journey from Cape Town to the rural Eastern Cape – but also a revisiting of the mental world of traditional Africa: ‘Here at home, here all guilt begins’ (‘Homecoming’). The return journey is haunted by nightmare memories of mental illness, the schizophrenic episodes accompanying (or occasioned by?) the poet’s initial encounters with modernity. This illness is represented as both pathological and cultural – a price paid for challenging and rejecting the old certainties while grappling with new assumptions: “He undermines the ancestors, That’s why he suffers. Let him.” (‘To Himself’)
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Pharmaceutical Pictograms: part 2: weird and wonderful interpretations
- Dowse, Roslind, Ehlers, Martina S
- Authors: Dowse, Roslind , Ehlers, Martina S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157037 , vital:40081
- Description: To assess the influence of formal education on the interpretation of pharmaceutical pictograms.
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- Authors: Dowse, Roslind , Ehlers, Martina S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157037 , vital:40081
- Description: To assess the influence of formal education on the interpretation of pharmaceutical pictograms.
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Dublin founders of ringing bells
- Authors: Lewis, Colin A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6174 , http://hdl.handle.net/10962/d1012366 , http://www.ringingworld.co.uk
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa. , The refurbishment and rehanging in a new frame in 1989 of the eight bells of St Patrick's Cathedral in Melbourne, Australia, was an indirect compliment to the quality of Irish workmanship. The bells, with a tenor of 13½ cwt, were cast in Dublin by Murphy's Bell Foundry to the order of Bishop Goold. They arrived in Melbourne in 1853. The bells were intended for St Francis' Church in Elizabeth Street, Melbourne, which had no tower! Eventually, in 1868, they were hung in the south tower of the cathedral. During the nineteenth and twentieth centuries there were at least four founders in Dublin who cast ringing bells: John Murphy, James Sheridan, Thomas Hodges and Matthew O'Byrne.
- Full Text:
- Authors: Lewis, Colin A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6174 , http://hdl.handle.net/10962/d1012366 , http://www.ringingworld.co.uk
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa. , The refurbishment and rehanging in a new frame in 1989 of the eight bells of St Patrick's Cathedral in Melbourne, Australia, was an indirect compliment to the quality of Irish workmanship. The bells, with a tenor of 13½ cwt, were cast in Dublin by Murphy's Bell Foundry to the order of Bishop Goold. They arrived in Melbourne in 1853. The bells were intended for St Francis' Church in Elizabeth Street, Melbourne, which had no tower! Eventually, in 1868, they were hung in the south tower of the cathedral. During the nineteenth and twentieth centuries there were at least four founders in Dublin who cast ringing bells: John Murphy, James Sheridan, Thomas Hodges and Matthew O'Byrne.
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Consideration of the effect of nutritional status and disease patterns on the work output amongst Black South African workers involved in manual materials handling (MMH) tasks
- Authors: Christie, Candice J
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6746 , http://hdl.handle.net/10962/d1009315
- Description: The prevalence of malnutrition amongst low-income earning South Africans has been well documented and is reported to be particularly high amongst Black South African males. This, combined with poor living conditions associated with their poor socio-economic status, results in an increased prevalence of infectious diseases amongst this sector of the population. Additionally, Black South African males are most often employed by companies requiring them to carry out heavy manual materials handling tasks. It would appear that limited research has focused on the relationship between inadequate dietary intake combined with poor health status and the impact this may have on the performance of manual workers. Energy intake is in all probability considerably less than energy expenditure.
- Full Text:
- Authors: Christie, Candice J
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6746 , http://hdl.handle.net/10962/d1009315
- Description: The prevalence of malnutrition amongst low-income earning South Africans has been well documented and is reported to be particularly high amongst Black South African males. This, combined with poor living conditions associated with their poor socio-economic status, results in an increased prevalence of infectious diseases amongst this sector of the population. Additionally, Black South African males are most often employed by companies requiring them to carry out heavy manual materials handling tasks. It would appear that limited research has focused on the relationship between inadequate dietary intake combined with poor health status and the impact this may have on the performance of manual workers. Energy intake is in all probability considerably less than energy expenditure.
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Guy Butler: 21 January 1918 - 26 April 2001
- Authors: Wright, Laurence
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:7053 , http://hdl.handle.net/10962/d1007413
- Description: [From Introduction]: For much of the last twenty-five years of his life, Butler’s thought and work were not perceived to be ‘current’ at all. His poetry was hardly read (what’s new there? – neither is anyone else’s); some of it lay in manuscript or obscure little publications until the Collected Poems appeared in 1999. The autobiographies attracted a loyal following amongst a small, educated reading public. His early dramas, though they met with initial success, were stifled by the poetic idiom to which they aspired, and by the racial claustrophobia against which they fought. (Demea, Butler’s South African reworking of the Medea, made it to the boards only in 1990 – the multi-racial cast, let alone the themes, kept it in hibernation until then.) The deluge of journalism and polemic suffered the usual fate of ephemera. Until resurrected by Stephen Watson in 1990, the essays and lectures remained buried in periodicals where they could not be assessed as a totality. His inspiring teaching was a gift to his students, hardly accessible to the wider society; and above all, much of his time was spent as homo commiticus, serving on the boards and sub-committees of numerous university institutions and other organizations, some of which he founded. In his autobiography, he observed wryly of his changed status following accession to the Chair of English at Rhodes in 1951: ‘Professors are not entirely themselves. Their interest as persons decreases because they are now public personages. Much of their time is spent on committees whose function is to pick the brains of individuals without giving them credit.’ Guy Butler gave generously of his brains in such circumstances.
- Full Text:
- Authors: Wright, Laurence
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:7053 , http://hdl.handle.net/10962/d1007413
- Description: [From Introduction]: For much of the last twenty-five years of his life, Butler’s thought and work were not perceived to be ‘current’ at all. His poetry was hardly read (what’s new there? – neither is anyone else’s); some of it lay in manuscript or obscure little publications until the Collected Poems appeared in 1999. The autobiographies attracted a loyal following amongst a small, educated reading public. His early dramas, though they met with initial success, were stifled by the poetic idiom to which they aspired, and by the racial claustrophobia against which they fought. (Demea, Butler’s South African reworking of the Medea, made it to the boards only in 1990 – the multi-racial cast, let alone the themes, kept it in hibernation until then.) The deluge of journalism and polemic suffered the usual fate of ephemera. Until resurrected by Stephen Watson in 1990, the essays and lectures remained buried in periodicals where they could not be assessed as a totality. His inspiring teaching was a gift to his students, hardly accessible to the wider society; and above all, much of his time was spent as homo commiticus, serving on the boards and sub-committees of numerous university institutions and other organizations, some of which he founded. In his autobiography, he observed wryly of his changed status following accession to the Chair of English at Rhodes in 1951: ‘Professors are not entirely themselves. Their interest as persons decreases because they are now public personages. Much of their time is spent on committees whose function is to pick the brains of individuals without giving them credit.’ Guy Butler gave generously of his brains in such circumstances.
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Population structure of Apis mellifera scutellata (Hymenoptera: Apidae) filling the Uganda gap
- Radloff, Sarah E, Hepburn, H Randall
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452017 , vital:75095 , https://hdl.handle.net/10520/EJC32956
- Description: Apis mellifera scutellata Lepeletier (Hymenoptera: Apidae) extends from South Africa to Ethiopia but includes local populations of varying morphology. The honeybees of Uganda previously represented an important biogeographical gap in defining the population structure of A. m. scutellata, but have now been resolved by morphometric analyses of worker honeybees analysed with multivariate techniques. Honeybees of lower altitudes (less than 2000 m) formed one distinct morphocluster typical of A. m. scutellata throughout the continent, while those at higher altitudes (less than 2000 m) formed a separate distinct cluster of large, dark bees. The latter occur as an archipelago of mountain ecotypes of A. m. scutellata..
- Full Text:
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452017 , vital:75095 , https://hdl.handle.net/10520/EJC32956
- Description: Apis mellifera scutellata Lepeletier (Hymenoptera: Apidae) extends from South Africa to Ethiopia but includes local populations of varying morphology. The honeybees of Uganda previously represented an important biogeographical gap in defining the population structure of A. m. scutellata, but have now been resolved by morphometric analyses of worker honeybees analysed with multivariate techniques. Honeybees of lower altitudes (less than 2000 m) formed one distinct morphocluster typical of A. m. scutellata throughout the continent, while those at higher altitudes (less than 2000 m) formed a separate distinct cluster of large, dark bees. The latter occur as an archipelago of mountain ecotypes of A. m. scutellata..
- Full Text:
Population structure of Apis mellifera scutellata (Hymenoptera: Apidae) filling the Uganda gap
- Radloff, Sarah E, Hepburn, H Randall
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452021 , vital:75096 , https://hdl.handle.net/10520/EJC32956
- Description: Apis mellifera scutellata Lepeletier (Hymenoptera: Apidae) extends from South Africa to Ethiopia but includes local populations of varying morphology. The honeybees of Uganda previously represented an important biogeographical gap in defining the population structure of A. m. scutellata, but have now been resolved by morphometric analyses of worker honeybees analysed with multivariate techniques. Honeybees of lower altitudes (less than 2000 m) formed one distinct morphocluster typical of A. m. scutellata throughout the continent, while those at higher altitudes (less than 2000 m) formed a separate distinct cluster of large, dark bees. The latter occur as an archipelago of mountain ecotypes of A. m. scutellata..
- Full Text:
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452021 , vital:75096 , https://hdl.handle.net/10520/EJC32956
- Description: Apis mellifera scutellata Lepeletier (Hymenoptera: Apidae) extends from South Africa to Ethiopia but includes local populations of varying morphology. The honeybees of Uganda previously represented an important biogeographical gap in defining the population structure of A. m. scutellata, but have now been resolved by morphometric analyses of worker honeybees analysed with multivariate techniques. Honeybees of lower altitudes (less than 2000 m) formed one distinct morphocluster typical of A. m. scutellata throughout the continent, while those at higher altitudes (less than 2000 m) formed a separate distinct cluster of large, dark bees. The latter occur as an archipelago of mountain ecotypes of A. m. scutellata..
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Rendering Primitives for a Virtual Holodeck
- Morkel, Chantelle, Bangay, Shaun D
- Authors: Morkel, Chantelle , Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432795 , vital:72901 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/039virtualholodeck/paper02.pdf
- Description: The main objective of this research is to implement a “Star Trek”-like holodeck in a computer environment. An experiment to create graphical primitives and images solely out of spheres is being conducted. We investigate several approaches of creating primitives using spheres, and then using these primitives to create images. Initial results of this experiment are presented and we conclude that using spheres to create primitives and images is a viable approach to creating realistic-looking three-dimensional (3D) images.
- Full Text:
- Authors: Morkel, Chantelle , Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432795 , vital:72901 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/039virtualholodeck/paper02.pdf
- Description: The main objective of this research is to implement a “Star Trek”-like holodeck in a computer environment. An experiment to create graphical primitives and images solely out of spheres is being conducted. We investigate several approaches of creating primitives using spheres, and then using these primitives to create images. Initial results of this experiment are presented and we conclude that using spheres to create primitives and images is a viable approach to creating realistic-looking three-dimensional (3D) images.
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Traditional veterinary medicine in the Alice district of the Eastern Cape Province, South Africa
- Dold, Anthony P, Cocks, Michelle L
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6513 , http://hdl.handle.net/10962/d1005941
- Description: Resource-poor farmers in rural and peri-urban areas have limited access to veterinary care in terms of support services (from state and private veterinarian and animal health technicians), information about the prevention and treatment of livestock diseases, and preventative and therapeutic veterinary medicines. This results in reduced productivity and in livestock disease and deaths, which is a great burden on these farmers, who can least afford the loss of their animals. There is a need to encourage disadvantaged farmers to use available resources and methods, at minimal cost, and to improve their productivity. One of these resources is ethnoveterinary medicine. A list of 53 plants used as veterinary medicines by stock farmers in the Alice district in the Eastern Cape is presented together with their preparation and methods of administration.
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- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6513 , http://hdl.handle.net/10962/d1005941
- Description: Resource-poor farmers in rural and peri-urban areas have limited access to veterinary care in terms of support services (from state and private veterinarian and animal health technicians), information about the prevention and treatment of livestock diseases, and preventative and therapeutic veterinary medicines. This results in reduced productivity and in livestock disease and deaths, which is a great burden on these farmers, who can least afford the loss of their animals. There is a need to encourage disadvantaged farmers to use available resources and methods, at minimal cost, and to improve their productivity. One of these resources is ethnoveterinary medicine. A list of 53 plants used as veterinary medicines by stock farmers in the Alice district in the Eastern Cape is presented together with their preparation and methods of administration.
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