The significance of the safety-net role of NTFPs in rural livelihoods, South Africa
- Authors: Paumgarten, Fiona
- Date: 2007
- Subjects: Non-timber forest products -- South Africa , Households -- Economic aspects -- South Africa , Rural development -- South Africa -- Economic aspects , Sustainable development -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4763 , http://hdl.handle.net/10962/d1007161 , Non-timber forest products -- South Africa , Households -- Economic aspects -- South Africa , Rural development -- South Africa -- Economic aspects , Sustainable development -- South Africa
- Description: This study was conducted in two rural villages in South Africa with the purpose of investigating the safety-net role of non-timber forest products (NTFPs). The use of NTFPs as a safety-net is reported as a common feature of rural livelihoods however empirical data supporting this function is limited. Therefore, policy makers and land-use planners underappreciate the probable role and consequent value of the safety-net function. The findings show that poor, rural households are vulnerable to a range of risks. Over a two year period 100% of households reported experiencing crises including unexpected idiosyncratic risks (e.g. illness, retrenchment, crop failure and death) as well as expected expenses and periods of vulnerability (e.g. the payment of school fees and seasonal crop shortfalls). Households are prone to these risks irrespective of wealth or gender of the de jure household head. To secure their livelihoods households in both villages rely on a variety of livelihood strategies including waged labour (53%), self-employment (30%), government grants (60%), arable agriculture (56%), animal husbandry (64%) and the use (100%) and sale (22%) of NTFPs. In terms of the proportion of households involved, the findings suggest land-based strategies make an important contribution. Formal employment and old-age pensions distinguish wealthy households from poor and allow for investments in assets and saving schemes (62%). In response to the risks experienced households employed a variety of coping strategies. Generally the most commonly used strategies were kinship (85%), reduced household spending (72%), changes to food consumption and saving (72%) and relying on NTFPs (70%). Kinship and NTFPs show no differences for wealth or gender of the de jure household head. The remaining strategies are influenced by wealth. The use of NTFPs as a safety-net manifested predominantly through the increased use of products, then the substitution of commercial goods by NTFPs and lastly through the sale. Of those using NTFPs as a rural safety-net 41.4% used of wild foods, 40% used medicinal plants, 25.7% substituted paraffin with fuelwood, 10% sold fuelwood and 8.6% sold other products.
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The use of Landsat ETM imagery as a suitable data capture source for alien acacia species for the WFW programme
- Authors: Cobbing, Benedict Louis
- Date: 2007
- Subjects: Geographic information systems , Global Positioning System , Landsat satellites , Agriculture -- Remote sensing , Geography -- Remote sensing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4856 , http://hdl.handle.net/10962/d1005532 , Geographic information systems , Global Positioning System , Landsat satellites , Agriculture -- Remote sensing , Geography -- Remote sensing
- Description: Geographic Information System technology today allows for the rapid analysis of vast amounts of spatial and non-spatial data. The power of a GIS can only be effected with the rapid collection of accurate input data. This is particularly true in the case of the South African National Working for Water (WFW) Programme where large volumes of spatial data on alien vegetation infestations are captured throughout the country. Alien vegetation clearing contracts cannot be generated, for WFW, without this data, so that the accurate capture of such data is crucial to the success of the programme. Mapping Invasive Alien Plant (IAP) data within WFW is a perennial problem (Coetzee, pers com, 2002), because not enough mapping is being done to meet the annual requirements of the programme in the various provinces. This is re-iterated by Richardson, 2004, who states that there is a shortage of accurate data on IAP abundance in South Africa. Therefore there is a need to investigate alternate methods of data capture; such as remote sensing, whilst working within the existing WFW data capture standards. The aim of this research was to investigate the use of Landsat ETM imagery as a data capture source for mapping alien vegetation for the WFW Programme in terms of their approved mapping methods, for both automated and manual classification techniques. The automated and manual classification results were compared to control data captured by differential Global Positioning Systems (DGPS). The research tested the various methods of data capture using Landsat ETM images over a range of study sites of varying complexity: a simple grassland area, a medium complexity grassy fynbos site and a complicated indigenous forest site. An important component of the research was to develop a mapping (classification) Ranking System based upon variables identified by WFW as fundamental in data capture decision making: spatial and positional accuracy, time constraints and cost constraints for three typical alien invaded areas. The mapping Ranking System compared the results of the various mapping methods for each factor for the study sites against each other. This provided an indication of which mapping method is the most efficient or suitable for a particular area.
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Trust on the semantic web
- Authors: Cloran, Russell Andrew
- Date: 2007 , 2006-08-07
- Subjects: Semantic Web , RDF (Document markup language) , XML (Document markup language) , Knowledge acquisition (Expert systems) , Data protection
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4649 , http://hdl.handle.net/10962/d1006616 , Semantic Web , RDF (Document markup language) , XML (Document markup language) , Knowledge acquisition (Expert systems) , Data protection
- Description: The Semantic Web is a vision to create a “web of knowledge”; an extension of the Web as we know it which will create an information space which will be usable by machines in very rich ways. The technologies which make up the Semantic Web allow machines to reason across information gathered from the Web, presenting only relevant results and inferences to the user. Users of the Web in its current form assess the credibility of the information they gather in a number of different ways. If processing happens without the user being able to check the source and credibility of each piece of information used in the processing, the user must be able to trust that the machine has used trustworthy information at each step of the processing. The machine should therefore be able to automatically assess the credibility of each piece of information it gathers from the Web. A case study on advanced checks for website credibility is presented, and the site presented in the case presented is found to be credible, despite failing many of the checks which are presented. A website with a backend based on RDF technologies is constructed. A better understanding of RDF technologies and good knowledge of the RAP and Redland RDF application frameworks is gained. The second aim of constructing the website was to gather information to be used for testing various trust metrics. The website did not gain widespread support, and therefore not enough data was gathered for this. Techniques for presenting RDF data to users were also developed during website development, and these are discussed. Experiences in gathering RDF data are presented next. A scutter was successfully developed, and the data smushed to create a database where uniquely identifiable objects were linked, even where gathered from different sources. Finally, the use of digital signature as a means of linking an author and content produced by that author is presented. RDF/XML canonicalisation is discussed in the provision of ideal cryptographic checking of RDF graphs, rather than simply checking at the document level. The notion of canonicalisation on the semantic, structural and syntactic levels is proposed. A combination of an existing canonicalisation algorithm and a restricted RDF/XML dialect is presented as a solution to the RDF/XML canonicalisation problem. We conclude that a trusted Semantic Web is possible, with buy in from publishing and consuming parties.
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Wheat stress responses during Russian wheat aphid and Bird Cherry Oat aphid infestation: an analysis of differential protein regulation during plant biotic stress responses
- Authors: Louw, Cassandra Alexandrovna
- Date: 2007
- Subjects: Russian wheat aphid , Plants, Effect of stress on , Wheat -- Diseases and pests , Rhopalosiphum , Plant proteins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3995 , http://hdl.handle.net/10962/d1004055 , Russian wheat aphid , Plants, Effect of stress on , Wheat -- Diseases and pests , Rhopalosiphum , Plant proteins
- Description: Plants possess a complex and poorly understood network of defence mechanisms that enable them to counteract the effects of abiotic and biotic stress. Aphid phloem feeding is source of biotic stress in plants. Russian wheat aphid and Bird Cherry-Oat aphid feeding cause significant losses in the annual wheat crop, and control by conventional methods such as pesticide application, has proved to be ineffective. Infestation by the Russian wheat aphid has a particularly devastating effect in South Africa. Aphid-resistant wheat cultivars have been identified but an incomplete understanding of the mechanism of the plant’s resistance thwarts the development of improved cultivars. A two-dimensional gel electrophoresis method was developed, partially optimised and validated in order to determine the effect of Russian wheat aphid and Bird Cherry-Oat aphid phloem feeding on the Betta and Betta DN wheat proteome. Differentially expressed proteins that were up or down regulated more than two fold were identified using PDQuest™ Basic software and matched to known wheat proteins stored in the SwissProt protein database on the basis of their molecular mass and isolectric point. Initial analysis of the differential protein expression of Betta and Betta DN wheat in response to Russian wheat aphid and Bird Cherry-Oat aphid phloem feeding at different growth stages revealed that younger plants display higher levels of resistance than older plants. Feeding by the Bird-Cherry Oat aphid does not result in the upregulation of proteins implicated in a defence response, which indicates that the damage incurred by the plant due to feeding by this aphid is not enough to trigger a classic defence response. Feeding by the more damaging Russian wheat aphid resulted in a stress response in susceptible wheat cultivar Betta, and a defence response in resistant wheat cultivar Betta DN. The infestation of Betta DN resulted in the upregulation of putative thaumatins and amylase trypsin inhibitors, indicating that the Betta DN resistance response could be due to the combined effect of protease inhibitors that discourage aphid phloem feeding and the activation of the salicylic acid and jasmonic acid plant defence pathways.
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