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Master of Science / Department of Statistics / Leigh Murray / An experiment was performed in 2005-2006 to determine if the variety of an alfalfa (Medicago sativa) crop rotation can effectively reduce the pest complex consisting of the yellow and purple nutsedge (YNS & PNS) weeds and the southern root-knot nematode (SRKN). During the 2005-2006 growing season, six months were selected to take samples from the alfalfa field (three months in 2005 and three months in 2006). The field was divided into 1m x 2m quadrats. Each month eighty quadrats were randomly selected. The counts of PNS, YNS and a soil sample (analyzed for the count of juvenile SRKN) were taken from each quadrat. In this study, two different ways were examined use [i.e. using] spatial information provided from the experiment to alter the original model. First spatial information was treated as fixed effects. Second spatial information was treated as random effects by modifying the residual variance matrix using various “spatial” variance-covariance structures. The results were compared to the original Poisson model and the spatial models to each other but did not have an effective way of comparing random effects models with the fixed effects models. For this data, the use of spatial statistics did not improve the original model consistently. This may be partly because of the nature of the experiment. The alfalfa effectively reduced the YNS, PNS, and SRKN counts. The spatial information was generally more useful earlier in the experiment when the YNS, PNS, and SRKN populations were denser.

Report submitted to the Faculty of Science, University of the Witwatersrand, in Partial fulfilment of the Requirements for Masters in Geographic Information Systems (GIS) and Remote Sensing in the Faculty of Science. School of Geography, Archaeology and Environmental Sciences, University of the Witwatersrand. March 2016. / This study is an initial attempt to investigate the spatial arrangement of graves which are believed that they can shed new light on the mortuary behaviours of ancient societies. The aim of this study is to utilise Geographic Information System (GIS) and remote sensing to document and explore the funerary landscape of the Wadi ash-Shati, Libya using a comprehensive set of environmental variables that might have influenced the spatial distribution of Garamantian funerary monuments. In view of that argument, this study is motivated by these two objectives; documenting all the Garamantian funerary monuments and settlements visible in high resolution satellite imagery and investigating their spatial patterns in their topographic setting. Spatial patterns were achieved by plotting digitised graves data from remotely sensed imagery (accessed through Google Earth) and hand held Global Positioning System (GPS) data in a GIS environment in order to extract patterns and structure in the dataset. In order to better understand these patterns and structures, the following GIS approaches; slope, elevation, visibility, clustering, directional distribution analyses were utilised. The results of the GIS analyses showed that there was correlation between graves location, qsurs or settlements, wells and with the environmental variables (slope, elevation, and distance to water resources). On the basis of the results of this research, it can be concluded that environmental variables were major factor in the placement of graves, qsurs and wells. The placement of these site locations can be related to as an expression of the socio-political, economic, cultural and ideological characteristics of the Garamantian society that created the burials and organised the Wadi ash-Shati landscape. The present study concluded that the Garamantian civilisation had established changes in the landscape that promoted the development of elaborate funerary monuments which peaked significantly during the time when aridity became immense in the study region. However additional research is necessary to provide more conclusive results and interpretations of this study, as such results from the analyses carried out should not be viewed as absolute, but as a stepping ladder for future investigation in the Wadi ash-Shati region. Keywords: GIS, Remote sensing, Funerary Landscape, Wadi ash-Shati, Libya, Spatial Analysis, Garamantian, Google Earth, Global Positioning System (GPS), Environmental Variables / LG2017

The study examined the effects of lesions of the thalamic nucleus medialis dorsalis (MD) made by neurotoxin in three cohorts ofrats to help understand the contribution of this nucleus to learning and memory. The lesions typically provided comprehensive damage to . MD, while the use of an excitotoxin helped to minimise damage to fibres of passage or adjacent fibre tracts. This excluded one confounding influence that may have been present in some previous studies. Some MD lesions also affected the anterior thalamic nuclei, and this additional damage led to spatial memory impairments, helping to confirm the value of results from rats with lesions confined to MD. Whilst the groups with MD lesions were largely unimpaired on non-spatial tests of visual recognition and discrimination, they were impaired on a configural discrimination task. The MD lesions did not impair spatial nonmatching to sample in aT-maze, nor the acquisition or performance over delay conditions of the standard radial maze task. There were impairments, however, when the radial maze was rotated during the delay, requiring a strategy shift. Similar impairment was found when a matching, rather than non-matching, strategy was required on the T-maze task and also when only some arms were rewarded on the radial arm maze task for reference memory measurement. No impairment was seen when the T-maze matching task was reversed to the non-matching variant, emphasising the lesion rats' preference for preexisting rules. In addition, some evidence was found that MD lesions brought about increased activity, but had no effect on conditioned place preference. The study concludes that MD damage in rats does not directly cause memory deficits. The influence that MD damage has on memory is, however, similar to that associated with damage to prefrontal cortex causing deficits in rule-switching ability, a higher order frontal lobe function.

Real-time optical intensity correlation using a photorefractive BSO crystal and a liquid crystal television is implemented. The underlying physics basis is considered, some specific techniques to improve the operation are proposed, and several optical pattern recognition tasks are achieved. Photorefractive BSO is used as the holographic recording medium in the real-time intensity correlator. To improve the dynamic holographic recording, a moving grating technique is adopted. The nonlinear effects of moving gratings at large fringe modulation are experimentally investigated, and are compared with numerical predictions. Optical bias is adopted to overcome the difficulty of a large drop in the optimum fringe velocity with moving gratings. The effects of optical bias on the optimum fringe velocity and on the diffraction efficiency are studied. To overcome the inherent drawback of low discrimination of intensity correlation in optical pattern recognition, real-time edge-enhanced intensity correlation is achieved by means of nonlinear holographic recording in BSO. Real-time colour object recognition is achieved by using a commercially available and inexpensive colour liquid crystal television in the intensity correlator. Multi-class object recognition is achieved with a synthetic discriminant function filter displayed by the Epson liquid crystal display in the real-time intensity correlator. The phase and intensity modulation properties of the Epson liquid crystal display are studied. A further research topic which uses the Epson liquid crystal display to realize a newly designed spatial filter, the quantized amplitude-compensated matched filter, is proposed. The performance merits of the filter are investigated by means of computer simulations.

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