The objective of this research was to investigate the nature of landowner supply-response behavior as it related to the land conversion process in the rural-urban fringe. Emphasis was placed on the derivation of the farmer's dynamic supply-response curve of agricultural land for urban uses since the nature of this curve has important implications for land-use policy alternatives in fringe areas. It was argued that the aggregate land market approach to land use policy analysis in the rural-urban fringe is generally inappropriate for practical and theoretical reasons. Consequently, a disaggregated micro model based on the proprietary land unit was developed to explain the land conversion process. The theoretical model is composed of three cost and two demand components. The interaction of these components results in a dynamic supply-response curve of agricultural land for urban uses which is discontinuous over a wide range for many classes of landowners. The theoretical model was tested through discriminant analyses of data collected from a study area where there exists heavy urban demand for agricultural land. The data included information on landowners over time, physical characteristics of the tracts of land, transfer information and· various demand variables. Results of the empirical analyses provided support for the hypotheses incorporated into the theoretical model. Specifically, empirical evidence was found to support the hypotheses that (1) individual farmers' supply response curves are discontinuous over a wide range, (2) farmers' fixed capital investment is a primary cause of the discontinuity, (3) farmers with less fixed capital investment will generally have more elastic supply-response curves which are discontinous over a smaller range, and (4) speculators' supply-response curves will generally be highly elastic and continuous. Various implications of the theoretical model for land-use policy analysis and land-use patterns in the rural-urban fringe are discussed. Particular attention was given to an analysis of Virginia's use-value assessment program based on the theoretical model. It was found that such a program will not "save" agriculture in fringe areas but will raise land price and subsidize speculative activities. Such a program might be more successful in achieving its stated goals if it were implemented in areas on the outlying edge of the rural-urban fringe. / Ph. D.

We analyzed how land-use patterns and changes in urbanization influence positive raccoon rabies cases in an established enzootic area. County resolution was used and the study area included all 159 counties in Georgia. We obtained data on raccoons submitted from 2006 through 2010 for testing at the state public health labs due to exposure incidents with people or domesticated animals. The land-use patterns were extracted from the US Geological Survey’s National Land Cover Database from both 2001 and 2006. Odds ratios were calculated on 16 land-use variables that included natural topography, agricultural development, and urbanization. An additional variable, Submissions/Population density, was used to normalize counties and to account for population bias associated with rabies surveillance. The use of this demographic variable was substantiated by GIS clustering analysis. The outcome variable was heavily right skewed and over dispersed and therefore a negative binomial regression was used in this count statistics technique. The final analysis showed that low intensity residential development is associated with raccoon rabies cases while evergreen forest offers protection. This study supports the hypothesis that the raccoon rabies enzootic is maintained in those edge ecosystems of urbanization. It is advocated here that the public health animal rabies database to include GPS coordinates when reporting wildlife rabies submissions for testing to improve the resolution when studying the disease ecology of enzootic rabies.

This thesis examines rural development processes, and in particular the impact over time of infrastructure investment on locational value in a farming community in northern Victoria, Australia. Correlation between infrastructure investment and land values was found to change over time, with the full cost of infrastructure provision not reflected in increased land values. Its impact depended on the type of infrastructure, and was linked to technological changes in agricultural production that led to different demands. The study also revealed the complexity of land ownership and use during the development of typical northern Victorian farmland, and the patterns of land value that emerged. As an historical study of land development it provides a deeper understanding of rural valuation methodology and sales analysis. It also contributes to the theory of land development, and in particular rural land-use and value.

Although much research exists on human behavior in online environments, research on users with disabilities is still rare. To draw more attention to this population, this dissertation explored browsing patterns and adaptive behaviors of people with visual disability across different online environments common in daily activities: social network, e-commerce, online information, and search engines’ websites. The main objective of this study is to propose a conceptual framework of how blind and visually impaired users browse and adapt to different web environments. We achieve this objective using a qualitative approach through three studies. In the first study, the researchers collect data by means of in-depth, semi-structured interviews with six users with different levels of visual impairment. In the second study, we use survey questionnaires with open-ended questions to reach a larger sample of study participants. Finally, we conduct a follow-up observational study as means to confirm our results. Open, axial, and selective coding are used for data reduction and analysis as part of the grounded theory method.

This study was conducted in the Borana rangelands, southern Oromia, Ethiopia with the aim of investigating land-use/cover changes, rangeland condition and indentifying major change drivers in the rangelands. Satellite image scenes, ground survey and people’s perceptions were assessed to identify changes on herbaceous and woody species composition. Ordination techniques were used for correlation of grass and woody species into environmental variables. Piospheric effects on vegetation composition around patch resources were also examined. These assessments were designed to bring out both spatial and seasonal variation in vegetation parameters. Rangeland condition was determined using the ecological index (EIM) and the weighted palatability composition (WPC) methods. Grazing capacity assessment was largely based on rain-use efficiency, range condition, density of woody plants. Woody cover in the Borana increased from 11.3% in the 1970s to 49.26% in 2000s, while, grassland cover declined from 58% to 32% during the same period. The cultivated/built up area also increased gradually over the years though the extent of increment was less compared to the woody cover changes. The calculated NDVI values for the 2000s were low relative to the 1970s. Ground survey results demonstrated that herbaceous biomass production and woody plant density varied significantly (P < 0.01) for the different sites in Borana. Nevertheless, herbaceous plant diversity and evenness did not differ significantly (P>0.05) across the different sites and around patch resource areas. This confirms the resilience of the Borana rangeland to the effects of grazing pressure and climatic variability. Overall, the density of woody plants varied from moderate to sever encroachment, which corresponds to the rangeland condition classes from very poor to fair. The results of the present study showed that the nutrient contents of herbaceous plants (CP, NDF, ADF, ADL and ash) were greatly influenced by species, stage of maturity, site and season. Herbaceous species with high crude protein content based on laboratory results were also ranked as the top important species by the pastoralists. Similarly, herbaceous forage species with a high structural fiber were considered inferior. Pastoralists’ knowledge and laboratory results on the nutritive value of key herbaceous species complemented each other. The stocking density of livestock units was higher than the grazing capacity for the Borana rangelands. Stocking density for the Borana rangeland using rain-use efficiency was 1.43 ha/TLU. There was no significant difference in the grazing capacity across the different sites in the study area under the existing management. The majority of pastoralists believed that the rangelands in Borana have been degraded, as consequence of recurrent drought (83%), population pressure (65%), poor management and inappropriate government policy (38%). The majority of the respondents (94%) also asserted that the traditional coping mechanisms of Borana pastoralists have declined. There is therefore a need for designing appropriate pastoral land-use policies that fit the ecological potential of the region to ensure sustainable ecosystem functioning. We suggest a comprehensive and adaptive range management for the implementation of appropriate land-use systems for the different livestock species. There is need to adjust stocking rates based on seasonal availability of forage. This would foster economic feasibility and ecological sustainability of the Borana pastoral production system. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Plant Production and Soil Science / Unrestricted

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Understanding how divergent selection results in the evolution of reproductive isolation (i.e. speciation) is an important goal in evolutionary biology. Populations of herbivorous insects using different host plant species can experience divergent selection from multiple selective pressures which can rapidly lead to speciation. Restio leafhoppers are a group of herbivorous insect species occurring within the Cape Floristic Region (CFR) of South Africa. They are specialised on different plant species in the Restionaceae family. Throughout my thesis I investigated how bottom-up (i.e. plant chemistry/morphology of host plant species) and top-down (i.e. predation and competition) factors drive specialisation and divergence in restio leafhoppers. I also investigated interspecific competition as an important determinant of restio leafhopper community structure. In chapter 2 I quantified host specificity of restio leafhopper species within a local community for 24 months. I found that restio leafhopper species are highly host specific and potentially synchronised with the growth phases of their host plants. In chapter 3 I used a network metric, modularity, to determine whether host plant partitioning in a restio leafhopper community is non-random (i.e. driven by a deterministic process). This metric allows the identification of the components underlying host plant partitioning (modules). I then performed experiments to show that modules, and therefore host plant partitioning, can mostly be explained by preference and performance relationships (i.e. bottom-up factors). In chapter 4 I used null models to test whether niche partitioning in restio leafhopper communities is a general pattern across the landscape. I found non-random niche partitioning, which results from strong host specificity, in all investigated restio leafhopper communities. In addition, I performed binary host choice experiments in the presence and absence of interspecific competition, but found no evidence that interspecific competition narrows host preferences. These findings suggest that host specificity, the cause of niche partitioning, is likely shaped over evolutionary time. Sampling multiple interaction networks across the CFR, in chapter 5, I tested whether restio leafhopper populations are more host specific in species rich communities and regions in the CFR than in species poor communities and regions. I found no positive relationship between restio leafhopper species richness and host specificity at any scale. These findings suggest that specialisation is not driven by interspecific competition. In chapter 6 I investigated host shifts in Cephalelus uncinatus. C. uncinatus has a broader distribution than any single restio species that it can use; suggesting that host plant related divergence may result from geographic range expansion. I found that allopatric and parapatric populations, but not sympatric individuals, using different host plants have divergent host preferences. I also found evidence for morphological divergence in traits related to predator avoidance in population pairs that exhibit divergent host preferences. My findings emphasise the importance of both bottom-up and top-down factors, with the exception of interspecific competition, as determinants of specialisation and divergence in restio leafhoppers. I find no evidence that interspecific competition is an important force structuring restio leafhopper communities. Instead, strongly niche partitioned community structure appears to emerge from the speciation process. / AFRIKAANSE OPSOMMING: Die wyse waarop uiteenlopende seleksie lei tot die evolusie van seksuele isolasie (n.l. spesiasie) is ‘n belangrike vraag in evolutionêre biologie. Plantetende insekpopulasieses wat verskillende gasheerplante gebruik kan onder uinteenlopende veelvoudige seleksie wees en vinnig spesiasie ondergaan. Restio-blaarspringers is ‘n groep plantetende insekspesies wat gespesialiseerd is op verskillende plantspesies in die restio familie. In my tesis ondersoek ek die onder-op (n.l. plantchemie en morfologie) en bo-af seleksiekragte (n.l. predasie en kompetisie) wat lei tot gasheerspesialisasie en -spesiasie in restio-blaarspringers. Ek ondersoek ook die belangrikheid van tussen-spesieskompetisie in gemeenskapsorganisasie. In hoofstuk 2 het ek gasheerspesialisasie gekwantifiseer in ‘n klein restio-blaarspringergemeenskap oor 24 maande. Ek het gevind dat restio-blaarspringers hoogs gasheerspesifiek is en moontlik met die groeifase van hul hoofgasheerplante gesinchroniseerd is. Ek het in hoofstuk 3 ‘n netwerkmetriek, modulariteit, gebruik om te bepaal of restio-blaarspringers se gasheerverdeling nie-stokasties is (n.l. deur deterministiese prosesse veroorsaak is). Hierdie metriek laat ‘n mens toe om die komponente van gasheerverdeling (modules) te identifiseer. Deur middel van eksperimente het ek bepaal dat modules, en dus gasheerverdeling, deur gasheervoorkeur en prestasie (onder-op prossesse) verduidelik kan word. In hoofstuk 4 het ek ondersoek of gasheerverdeling algemeen is. Ek het deur middel van nulmodelle gewys dat gasheerverdeling algemeen is en veroorsaak is deur sterk gasheerspesifiekheid. Ek het ook voorkeureksperimente uitgevoer in die teenwoordigheid en afwesigheid van tussen-spesies kompetisie. Hier het ek geen teken gevind dat huidige tussen-spesies kompetisie gasheervoorkeur beïnvloed nie. My bevindinge in hierdie hoofstuk stel dus voor dat spesialisasie, die oorsaak van gasheerverdeling, oor evolutionêre tyd gevorm word. In hoofstuk 5 het ek ondersoek of populasies van restio-blaarspringers meer gasheerspesifiek is in restio-blaarspringerspesies ryke gemeenskappe en streke as populasies in spesies-arm gemeenskappe en streke. Ek het geen positiewe korrelasie tussen spesiesrykheid en gasheerspesialisasie gevind nie. Dit dui daarop aan dat gasheerspesialisasie, en dus gasheerverdeling, nie deur tussen-spesies kompetisie veroorsaak word nie. In hoofstuk 6 het ek gasheerplantgekoppelde divergensie ondersoek in Cephalelus uncinatus. C. uncinatus se verspreiding is breër as enige restio-spesies wat dit kan gebruik. Dit stel voor dat verspreidingvergroting gasheerverskuiwing mag veroorsaak. Ek het gevind dat populasies wat verskillende plante in allopatrie en parapatrie gebruik uiteenlopende gasheerkeuses maak, maar insekte wat verskillende plante in sympatrie gebruik wys nie ontwrigtende gasheerkeuses nie. Die populasies wat uiteenlopende gasheerkeuses getoon het, het ook verskillende morfologiese teen-predasie eienskappe getoon. Dit dui daarop aan dat predasie belangrik mag wees vir spesiasie in restio-blaarspringers. Die bevindinge van my tesis dui daarop aan dat beide onder-op en bo-af seleksie belangrik is vir gasheer-spesialisasie in divergensie. Nietemin, tussen-spesies kompetisie is nie ‘n belangrike bron vir spesialisasie, divergensie of gemeenskapsorganisasie nie. Gemeenskapsorganisasie is klaarblyklik slegs ‘n gevolg van die spesiasie proses.

This thesis examines the space use, movement and contact rate patterns of a high- density, group-living, Eurasian badger (Meles meles) population in the UK naturally infected with bovine tuberculosis (bTB). Recently developed proximity logging devices were deployed on a representative sample of 51 badgers from eight different social groups to track their movements using radio-telemetry and to quantify their within- and between-group contact rates. Whilst interactions within social groups accounted for more than 90% of contacts, the entire study population was ultimately connected through interactions among individuals from neighbouring groups. Both within and between-group contacts, and also the use of denning sites, were heavily influenced by seasonal and demographic factors, which appear to be motivated to a large extent by reproductive behaviours. Nevertheless, by using social network analysis I found that badgers that tested positive for bTB were found to interact with fewer of their group members and for a shorter amount of time. Specifically these test-positive individuals were found to associate with test-negative group members significantly less than would be expected by chance. Those animals testing positive for bTB were also found to use outlying setts significantly more frequently than those that tested negative. The within and between-group contact rates of individuals were found to correlate with their sett use patterns. Those animals that spent less time interacting with group members and those that spent more time interacting with members of foreign social groups, were found to spend a greater proportion of their time at outlier setts. The findings in this thesis suggest a link between wider roaming behaviour and the disease status of an individual. This adds support to the argument that the social disruption of badger populations, for example through culling, may promote rather than alleviate the spread of bTB as a result of increased movement and contacts between groups. State-of-the-art technology has enabled me to demonstrate the strong influence that badger social organisation may have on the transmission of an economically significant infectious disease. My findings suggest that disease control measures might be enhanced by taking into account seasonal and individual-level variation in ranging behaviour and use of outlier setts, for example, by identifying and targeting functional groups of individuals, specific areas, or times of the year that contribute disproportionately to disease spread.

The topic of this thesis is use of alcohol in people after spinal cord injury, who form a specific group of people with disabilities. Objectives of the research work The objective of this thesis is to describe the incidence and rate of alcohol use in people after spinal cord injury and find any specifics of alcohol use for this target group. As well as describe motives and reasons for alcohol use, specifics of individual diagnoses, find and define health problems related to alcohol use in people after spinal cord injury. Last but not least, find out whether in this specific group individuals with symptoms of harmful alcohol use (alcohol abuse) or addiction to alcohol appear. Sample file Participants of research (sample file) in this thesis are people after spinal cord injury who are members of the civic association CZEPA. The main objective of this association is to defend the rights and interests of people after spinal cord injury and strives for their full integration into society. Data processing methods With an electronic questionnaire (self-questionnaire in combination with the AUDIT questionnaire) frequency and intensity of alcohol use, seriousness of alcohol intake, health state and other consequences ware measured in people after spinal cord injury. The data were analyzed by the IBM SPSS...

<p>The study has several implications / for general theoretical traditions it highlights the point that ambivalent attitudes and incomplete language use are responsible for gradual language decline. Previous studies while acknowledging the role of community based, intuitive conditions on language maintenance and shift, did not show how the process occurred. For policy the study aims toward sensitizing policy makers and raise their awareness about the dire situation in which minority languages currently are in. This would ensure that politicians, bureaucrats, and other state authorities could implement policy decisions that guarantee protection of minority languages and enhance their vitality. One policy strategy that could ensure revitalization of minority languages would be to include them in the school curriculum as supplementary approach to the effort of the home and the community, as McCarty (2002, quoted in Recento, 2006) observes that schools / [&hellip / ] can be constructed as a place where children can be free to be indigenous in the indigenous language &ndash / in all of its multiple and everchanging meanings and forms.</p>

<p>The study has several implications / for general theoretical traditions it highlights the point that ambivalent attitudes and incomplete language use are responsible for gradual language decline. Previous studies while acknowledging the role of community based, intuitive conditions on language maintenance and shift, did not show how the process occurred. For policy the study aims toward sensitizing policy makers and raise their awareness about the dire situation in which minority languages currently are in. This would ensure that politicians, bureaucrats, and other state authorities could implement policy decisions that guarantee protection of minority languages and enhance their vitality. One policy strategy that could ensure revitalization of minority languages would be to include them in the school curriculum as supplementary approach to the effort of the home and the community, as McCarty (2002, quoted in Recento, 2006) observes that schools / [&hellip / ] can be constructed as a place where children can be free to be indigenous in the indigenous language &ndash / in all of its multiple and everchanging meanings and forms.</p>