Since the establishment of West Nile virus (WNV) in North America, concern has arisen that this virus may also pose a biosecurity threat to Australia. West Nile virus is maintained in an enzootic transmission cycle between birds and ornithophilic Culex spp. mosquitoes. Since its introduction into the United States in 1999, it has been responsible for over 11,000 human cases of neurological disease and over 1,000 human deaths. In addition, WNV has caused extensive equine and avian mortality. Should an exotic, virulent strain of WNV be introduced into Australia, it may have significant impact on human and animal health. This thesis examines entomological factors which may influence the potential for an exotic, pathogenic strain of WNV to become established in eastern Australia and be maintained in urban transmission cycles. Further, it aims to elucidate the most likely candidate vectors for the maintenance of WNV in natural transmission cycles. Components include: a) laboratory-based vector competence experiments to assess the ability of Australian mosquito species to become infected with and transmit a North American strain of WNV; b) identification of the vertebrate origin of mosquito bloodmeals using serological and molecular assays; c) an evaluation of the efficacy of bird-baited traps for collecting ornithophilic mosquitoes at ground level and in the tree canopy; and d) examination of the prevalence of endemic arboviruses, including Kunjin virus (KUNV; an Australian subtype of WNV) in mosquitoes collected from urban centres of eastern Australia. Vector competence experiments were conducted with field-collected Australian mosquito species. Nineteen species were were exposed to a 1999 New York strain of WNV using an artificial membrane feeding apparatus and transmission was attempted using an in vitro modified capillary tube method. A number of Culex species, including Culex quinquefasciatus and Culex gelidus, demonstrated high vector competence for WNV. Culex annulirostris, the primary KUNV vector, was the most competent vector, displaying transmission rates of 84%. Other common species, including Aedes vigilax, Aedes procax and Verrallina spp. were less susceptible to infection. Approximately 1,200 blood engorged mosquitoes were analysed using an enzyme-linked immunosorbent assay to determine host species. Overall, 90% of bloodmeals from Cx. quinquefasciatus were avian in origin, while 22% of bloodmeals from Cx. annulirostris were from birds. Molecular assays were further used to determine which bird species were commonly targeted by a selection of ornithophilic mosquito species. Mitochondrial DNA sequence data indicated that most (93%) avian bloodmeals from Cx. quinquefasciatus were obtained from passerine birds (order Passeriformes). Avian species commonly targeted by Cx. quinquefasciatus included Sphecotheres vieilloti (Australasian figbird; 39% of total identified), Sturnus tristis (common myna; 19%) and Philemon buceroides (helmeted friarbird; 17%). Alternatively, the majority (87%) of avian bloodmeals identified from Cx. annulirostris were from non-passerine birds, with most bloodmeals obtained from ducks (72%; family Anatidae). Seven field-based Latin Square trials conducted in Brisbane and Cairns showed that conventional CO2-baited CDC traps yielded higher numbers of Culex spp. than novel bird-baited traps, both at ground level and in the tree canopy. In Brisbane, CO2-baited CDC traps placed at ground level (approximately 1 m from ground) collected significantly more Cx. annulirostris than those at canopy height (5-10 m) during two trials, and more Ae. vigilax and Aedes procax during one trial each. Conversely, in Cairns, CO2-baited CDC traps placed in the tree canopy collected significantly more Culex squamosus during two trials, and significantly more Aedeomyia catasticta and Culex cubiculi during one trial each. Consistently low yields of ornithophilic species including Culex australicus and Cx. quinquefasciatus in all traps tested suggests the need to employ alternative trapping measures to target these species in urban areas. Over 1,800 mosquito pools (comprising over 65,000 individual mosquitoes collected from urban environments) were tested for evidence of arboviral infection. None of the pools showed evidence of flavivirus infection, but two alphaviruses were isolated from mosquito pools from Cairns. One isolate of Barmah Forest virus was obtained from a pool of 100 Ae. vigilax, and a pool of 89 Verrallina carmenti yielded an isolate of Ross River virus. In addition, an isolate most similar to a newly described bunyavirus, Stretch Lagoon orbivirus, was obtained from a single Aedes alternans collected from Sydney. The outcomes of this thesis demonstrate that a number of Australian mosquito species can become infected with and transmit a virulent strain of WNV, should it be introduced into Australia. Analysis of the host feeding patterns of these potential vectors in urban environments demonstrates that a number of candidate vectors, including Cx. quinquefasciatus and Cx. annulirostris, readily feed on common bird species. Further, the absence of detectable flavivirus infection in urban mosquito populations shown here suggests that endemic urban flaviviruses would have minimal influence on potential WNV transmission. Notwithstanding other ecological factors that may influence the likelihood of enzootic or epizootic transmission including susceptibility of vertebrate hosts and mechanisms of introduction, the potential establishment of an exotic, virulent strain of WNV in urban areas of Australia is certainly possible given the evidence provided in this thesis.

Real-world learning tasks present a range of issues for learning systems. Learning tasks can be complex and the training data noisy. When operating as part of a larger system, there may be limitations on available memory and computational resources. Learners may also be required to provide results from a stream. This thesis investigates the problem of incremental, relational learning from imperfect data with constrained time and memory resources. The learning process involves incremental update of a theory when an example is presented that contradicts the theory. Contradictions occur if there is an incorrect theory or noisy data. The learner cannot discriminate between the two possibilities, so both are considered and the better possibility used. Additionally, all changes to the theory must have support from multiple examples. These two principles allow learning from imperfect data. The Minimum Description Length principle is used for selection between possible worlds and determining appropriate levels of additional justification. A new encoding scheme allows the use of MDL within the framework of Inductive Logic Programming. Examples must be stored to provide additional justification for revisions without violating resource requirements. A new algorithm determines when to discard examples, minimising total usage while ensuring sufficient storage for justifications. Searching for revisions is the most computationally expensive part of the process, yet not all searches are successful. Another new algorithm uses a notion of theory stability as a guide to occasionally disallow entire searches to reduce overall time. The approach has been implemented as a learner called NILE. Empirical tests include two challenging domains where this type of learner acts as one component of a larger task. The first of these involves recognition of behavior activation conditions in another agent as part of an opponent modeling task. The second, more challenging task is learning to identify objects in visual images by recognising relationships between image features. These experiments highlight NILE'S strengths and limitations as well as providing new n domains for future work in ILP.

Thesis (M.S.)--University of Nevada, Reno, 2006. / "December, 2006." Includes bibliographical references (leaves 29-33). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2006]. 1 microfilm reel ; 35 mm.

Thesis (Ph.D.)--University of Alabama at Birmingham, 2010. / Title from PDF title page (viewed on July 7, 2010). Includes bibliographical references.

Thesis (M.S.)--Wildlife and Fisheries Sciences Dept., South Dakota State University, 2009. / Includes bibliographical references (leaves 80-102). Also available via the World Wide Web.

Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, June 2010. / Thesis Advisor(s): Borer, Douglas A. ; Second Reader: Simons, Anna. "June 2010." Description based on title screen as viewed on July 14, 2010. Author(s) subject terms: Upstream states, Downstream states, sovereign territory, equitable utilization, national security, conflict, water scarcity, Nile river/basin, hegemony, control, legitimacy, absolute territorial sovereignty, natural rights, absolute integrity, acquired rights, negotiations, contentious agreements, prior appropriation, virtual water, interstate relations, competitive exploitation, political stability/instability, compromise, cooperation, unilateralism, food security, regional security, strategic interests, sustainable exploitation, riparian co-dependence, limited territorial sovereignty, limited integrity, arbitration, asymmetry. Includes bibliographical references (p. 71-74). Also available in print.

Thesis (M.S.) -- Mississippi State University, 2006. / Includes bibliographical references (p. 91-96). Available online in PDF format.

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Gregory D. Johnson. Includes bibliographical references (leaves 60-66).

Thesis (M.A.)--University of South Florida, 2006. / Title from PDF of title page. Document formatted into pages; contains 86 pages. Includes bibliographical references.

Thesis (MA (Geography and Environmental Studies))--University of Stellenbosch, 2006. / The Okavango river along the panhandle of the Delta, in Botswana, is home to many wildlife species as well as to many large village communities. Local communities rely on the riverine system and its resources for subsistence and commerce. Activities associated with the utilization of these resources are governed by the fluctuating water levels of the river, which inhibit access during high water levels and allow access during low water levels. The high intensity of activities, such as reed harvesting, fishing and increased tourism, during low water periods coincides with the breeding season of many wildlife species in the system, including the Nile crocodile (Crocodylus niloticus). Over 90% of crocodile breeding areas in the Delta are found only in the panhandle region. The association between the intensity of human activities in the floodplains and crocodile nesting activity means that much of the habitat required for nesting is vulnerable to human disturbance and this could have severe negative impacts on the future of the Okavango crocodile population. The study evaluated habitat vulnerability by mapping and spatially comparing habitat suitability, based on optimum environmental requirements for crocodile nesting, and human disturbance factors. A detailed crocodile nesting survey was carried out to locate and test all nesting sites according to criteria selected by species experts. The results from the survey were used to locate suitable nesting habitat in the study area by analysis in a Geographic Information System (GIS). Disturbance factors were visually identified and their locations in the study area spatially mapped. Their spatial influences on crocodile nesting were used as factors in a Multi-Criteria Evaluation (MCE) that evaluated the combined effect of the disturbances on the area defined as suitable crocodile habitat. The results indicate the extent of habitat vulnerable to human disturbances. The results from the study show that 59% of once suitable crocodile habitat is currently disturbed by human activities. Most of the remaining 41% of undisturbed habitat is located along the Moremi/Phillipa side channel, which represents a core area for protection measures to be instated. The study recommends the declaration of a crocodile nesting sanctuary in this side channel to ensure the breeding success of this keystone species.