Ticks (Ixodes (Ceratixodes) uriae] were collected from two seabird colonies on the Isle of May in Scotland. Viruses were isolated from three tick pools, one from ticks collected during 1979 and two from ticks collected during 1981. The viruses replicated in suckling mouse brain, chick embryo fibroblasts, Vero and BHK-21 cells, but not in Xenopus cells. By virtue of their morphology in infected cells, physicochemical properties and reactions in complement fixation tests, they were identified as Kemerovo serogroup viruses belonging to the Great Island Complex (Orbivirus:Reoviridae). Ihe three isolates were distinguished from each other by plaque reduction neutralization tests. After three cycles of plaque purification, the replication of one isolate, Mill Door/79 virus, was examined in Vero and BHK-21 cells. The virus grew to maximum titres 8 to 9 hours post infection (p.i.); over 99% of the infectivity was cell-associated. Twelve virus-specified polypeptides, p141, p93, p69, p65, p53/51, p44, p37, p36, p30, p27, p21 and p20 were identified in infected Vero cell lysates by polyacrylamide gel electrophoresis (PAGE). Similar polypeptide profiles were observed in infected BHK-21 cell lysates. Attempts to purify the virus, by polyethylene glycol-6000 precipitation, resulted in the detection of p93, p69, p53/51, p37, p21 and p20 after PAGE, whereas only four, p93, p69, p53/51 and p37 were detected after attempts at purification using ether extractions. Results using pr~ase inhibitors and partial proteolysis indicated that three virus-specified polypeptides (p36, p30 and p27) may be cleavage products. All virus-specified polypeptides, with the exception of p30 and p20, were labelled in infected cell cultures with both [14c] mannose and [14c] glucosamine.

The biology and ecology of the earthworm Lumbricus rubellus Hoffmeister, 1843, and its effects on the turn-over of organic matter and soil are not well known. To gather this information, the ingestion and egestion rates were measured using a litterbag technique and the transport of organic matter was quantified with a newly developed method, using soil columns to which ¹⁴C labelled plant material was added. The feeding habits of the worm were positively influenced by temperature in wet soils (> -15m of water) and were negatively influenced in dry soil (< -15 m of water). The total egestion rate changed from 0.3 g.g⁻¹.day⁻¹ at 5 °C to 1.0 g.g⁻¹. day⁻¹ at 20° C in moist soil (- 5 m of water). The egestion rate at medium range temperatures, 10 and 15° C, was less affected by drought stress than at 5 and 20 °C. The egestion rate of carbon was a more stable parameter than the total egestion rate, and ranged from approximately 20 mg.g⁻¹.day⁻¹ at 5 °C, to 50 mg.g⁻¹.day⁻¹ at 20 °C. The moisture and temperature effects were apparent in the Q₁₀ of the total egestion rate and of the egestion rate of carbon. The Q₁₀ ranged from 1.66 in wet soils to 3.27 in dry soils in the 5-15 °C interval and from 1.98 to 0.32 in the 10-20 °C range. For the egestion rate of carbon, the Q₁₀ ranged from 1.92 to 3.21 and from 1.28 to 0.47, respectively. The body water content of the worm varied considerably with the soil water potential, and reached a maximum level of 5.5 kg.kg⁻¹ (dwt) between -15 metres of water and -30 metres of water. When under drought stress, worms stopped ingesting large quantities of soil, switched to a diet high in organic matter and lowered their activity. In the ¹⁴C column experiment, the total cast production was significantly related to depth. L. rubellus produced 15 % of the cast on the surface of the soil, 46 % in the 0-5 cm layer, 22 % in the 5-10 cm layer and 16 % in the 10-15 cm layer. Independent calculations from a) the uptake of ¹⁴C labelled carbon in earthworms, b) removal of litter from the surface and c) ¹⁴C label recovered from cast, showed that the worms ingested 78-82 % of the offered organic matter as shoot litter and 18-22 % as root litter. ¹⁴C originating from shoot and root litter was recovered in casts throughout the profile, indicating that the worms mixed food from all layers. The total egestion rate found in the column experiment was 5.2 times higher than was found in the litterbag technique under comparable conditions (2.34 vs 0.45 g.g⁻¹.day⁻¹). The egestion rate of carbon was similar in both techniques (37.1 vs. 46.1 mg.g⁻¹.day⁻¹, 10 °C). In preliminary litterbag trials, it was found that L. rubellus egested 15.5 mg.g⁻¹.day⁻¹ of carbon (5 °C) for each of four food types offered. The 5 °C temperature trial of the litterbag technique, showed a similar amount of carbon egested. It was concluded that the worm needed a constant amount of carbon to provide nutrients and energy, of which a part or all may originate from ingested microorganisms. Based on the distribution of cast in the profile and the feeding strategies of L. rubellus, it was concluded that this earthworm cannot be classified as an epigeic worm. A new strategy class was proposed: eurygeic worms, earthworms living in the litter-soil interface, mixing organic matter into the profile and mineral soil into the litter layer. Based on the literature and results from the present study, a computer model was developed to simulate the longterm effects of earthworms on an agricultural soil system. Simulations of the mixing of soil and organic matter in a limited-till agricultural system, showed that earthworms negatively affected the accumulation rate of surface litter and positively affected the organic matter content of the mineral soil. The model can be used to predict the trends in organic matter in soils, important in soil conservation, mine reclamation and reforestation. / Land and Food Systems, Faculty of / Graduate

The integrated processing and interpretation of VSP data are developed to work together in order to enhance the final VSP interpretation. Furthermore, the interpretive processing of the VSP data within the case histories are reviewed along with the incorporation of the final VSP results (both near and far offset data) into the integrated geological/geophysical interpretations presented in the case studies. This thesis has attempted to personify the term "interpreter/processor" as first highlighted in Hardage (1985). The case histories pertain to oil and gas exploration in carbonate reef and sandstones in the Western Canadian Sedimentary Basin (WCSB). The Lanaway case history (Hinds et al., 1994a) pertains to the exploration of the Lanaway/Garrington oil field located in central Alberta, Canada. The surface seismic interpretation over the reef crest differed dramatically from the isopach of the reef-encasing shales derived from the geological logs of a borehole drilled into the reef crest. To understand the discrepancy, a VSP survey was performed and the data were interpretatively processed. The results were integrated with the known geology of the field area to uncover possible reasons for the surface seismic anomaly. field in central Alberta, Canada, using the far offset VSP survey. Existing surface seismic was used to infer that a well drilled into the interpreted North-east corner of the Ricinus reef would be successful in penetrating oil bearing carbonate reef. The well was drilled; however, the well missed the reef and a near and far offset VSP survey was used to seismically image possible reef buildups in an area around the well. The Fort St. John Graben case history (Hinds et al., 1991a; Hinds et al., 1993a) highlights exploration of a gas-filled channel sandstone using near and far offset (lateral) VSP surveys. An exploration well was drilled within the study area which intersected the target zone sandstone (the basal Kiskatinaw of the Upper Carboniferous). The target sandstone had a high shale content and was not reservoir quality. A near offset and two far offset VSP surveys were run in the exploration well to image out to a distance of 350 m to the North-west and to the East of the well. The VSP, surface seismic and geology results (from the geological logs of the exploration and surrounding wells) are integrated to infer a clearer picture of the sand/shale relationships of the basal Kiskatinaw and detailed faulting of the Carboniferous strata around the well and within the surface seismic line area. The Simonette field case history (Hinds et al., 1991 b; Hinds et al., 1993b) involves using VSP results to image the slope of a low-relief carbonate reef. The low-relief reef examined using the VSP data is located at the extreme end of a North-east reef spur of the Simonette Reef located in North-west Alberta, Canada. An exploration well drilled in the low-relief reef penetrated the edge of the reef. The VSP surveys were run in order to infer details of the reef slope. The interpretation of the VSP data was integrated with all other exploration data to infer the location of the crest of the low-relief reef and to assist in determining whether to whipstock the exploration well or not. / Thesis (DSc)--University of Pretoria, 2010. / Geology / unrestricted

The integrated processing and interpretation of VSP data are developed to work together in order to enhance the final VSP interpretation. Furthermore, the interpretive processing of the VSP data within the case histories are reviewed along with the incorporation of the final VSP results (both near and far offset data) into the integrated geological/geophysical interpretations presented in the case studies. This thesis has attempted to personify the term "interpreter/processor" as first highlighted in Hardage (1985). The case histories pertain to oil and gas exploration in carbonate reef and sandstones in the Western Canadian Sedimentary Basin (WCSB). The Lanaway case history (Hinds et al., 1994a) pertains to the exploration of the Lanaway/Garrington oil field located in central Alberta, Canada. The surface seismic interpretation over the reef crest differed dramatically from the isopach of the reef-encasing shales derived from the geological logs of a borehole drilled into the reef crest. To understand the discrepancy, a VSP survey was performed and the data were interpretatively processed. The results were integrated with the known geology of the field area to uncover possible reasons for the surface seismic anomaly. field in central Alberta, Canada, using the far offset VSP survey. Existing surface seismic was used to infer that a well drilled into the interpreted North-east corner of the Ricinus reef would be successful in penetrating oil bearing carbonate reef. The well was drilled; however, the well missed the reef and a near and far offset VSP survey was used to seismically image possible reef buildups in an area around the well. The Fort St. John Graben case history (Hinds et al., 1991a; Hinds et al., 1993a) highlights exploration of a gas-filled channel sandstone using near and far offset (lateral) VSP surveys. An exploration well was drilled within the study area which intersected the target zone sandstone (the basal Kiskatinaw of the Upper Carboniferous). The target sandstone had a high shale content and was not reservoir quality. A near offset and two far offset VSP surveys were run in the exploration well to image out to a distance of 350 m to the North¬west and to the East of the well. The VSP, surface seismic and geology results (from the geological logs of the exploration and surrounding wells) are integrated to infer a clearer picture of the sand/shale relationships of the basal Kiskatinaw and detailed faulting of• the Carboniferous strata around the well and within the surface seismic line area. The Simonette field case history (Hinds et al., 1991 b; Hinds et al., 1993b) involves using VSP results to image the slope of a low-relief carbonate reef. The low-relief reef examined using the VSP data is located at the extreme end of a North-east reef spur of the Simonette Reef located in North-west Alberta, Canada. An exploration well drilled in the low-relief reef penetrated the edge of the reef. The VSP surveys were run in order to infer details of the reef slope. The interpretation of the VSP data was integrated with all other exploration data to infer the location of the crest of the low-relief reef and to assist in determining whether to whipstock the exploration well or not. / Thesis (DSc)--University of Pretoria, 1994. / Geology / unrestricted

Increasing interest in the role of wetlands in pollutant removal, flood plain management, and sedimentation in recent years has prompted research into hydraulic processes inherent to these systems. The research described in this thesis focuses on flow processes within ecosystems known as riparian wetlands. An attempt has been made to summarize existing research in this field to ensure that a contribution will be made to the field of hydraulics. Included in this thesis are results from laboratory models investigating flow through vegetation in riparian wetlands. Particular emphasis in this research has been placed on velocity profile measurement of flow within vegetation. Measurements were taken within various density configuration of rigid simulated vegetation for emergent and submerged cases. In addition, many of the experiments tested the effect on the velocity profile when two distinct layers of vegetation are present. The results described herein should aid in visualization of flow processes within riparian wetlands. / Master of Science

No description available.

MSc (Dent), Orthodontics, Faculty of Health Sciences, University of the Witwatersrand / This study evaluated the influence of age on the perception of facial attractiveness in three samples of South Africans. Eight digitally morphed lateral facial profiles were created by means of computer animation software and presented, in sequential order, to 1798 school learners, 694 university students and 323 school teachers. Each participant was asked to complete a questionnaire in addition to choosing a single face he/she perceived to be the most attractive. Statistical tests included frequency distributions, percentages, cross-tabulations, odds ratios and the Pearson Chi-square test. Results demonstrated that age was a factor in the perception of facial attractiveness particularly amongst individuals of school-going age. Thereafter, increasing age did not exert a significant influence on the perception of profile preference. There was a definite trend towards the preference for less protrusive facial profiles. Nevertheless, due consideration should be given to the individuality associated with aesthetic choices as a significant proportion of raters did indicate a preference for profiles exhibiting mild protrusion. Furthermore, race and cultural background do appear to play a significant role in the perception of facial profile preferences. It is suggested that future studies of a similar nature be undertaken in order to provide the data to permit comparison with the results reported in this study.

This thesis describes a new method of calculating data priority by using adaptive mobile user and device profiles which change with user location, time of the day, available networks and data access history. The profiles are used for data prefetching, selection of most suitable wireless network and cache management on the mobile device in order to optimally utilize the device�s storage capacity and available bandwidth. Some of the inherent characteristics of mobile devices due to user movements are �non-persistent connection, limited bandwidth and storage capacity, changes in mobile device�s geographical location and connection (eg. connection can be from GPRS to WLAN to Bluetooth). New research is being carried out in making mobile devices work more efficiently by reducing and/or eliminating their limitations. The focus of this research is to propose, evaluate and test a new user profiling technique which specifically caters to the needs of the mobile device users who are required to access large amounts of data, possibly more than the device storage capability during the course of the day or week. This work involves the development of an intelligent user profiling system along with mobile device caching system which will first allocate weight (priority) to the different sets and subsets of the total given data based on user�s location, user�s appointment information, user�s preferences, device capabilities and available networks. Then the profile will automatically change the data weights with user movements, history of cached data access and characteristics of available networks. The Adaptive User and Device Profiles were designed to handle broad range of the issues associated with: �Changing network types and conditions �Limited storage capacity and document type support of mobile devices �Changes in user data needs due to their movements at different times of the day Many research areas have been addressed through this research but the primary focus has remained on the following four core areas. The four core areas are : selecting the most suitable wireless network; allocating weights to different datasets & subsets by integrating user�s movements; previously accessed data; time of the day with user appointment information and device capabilities.

In their natural environment animals must balance their safety requirements (i.e., avoiding predation) with their need to satisfy their energy demands (i.e., securing food). How the brain integrates these competing demands to promote adaptive responding is not well understood. The current study examined the effects of chronic food restriction on rats' behavioural defense profiles in two animal models of anxiety; the shock-probe burying and elevated plus-maze tests. In agreement with previous research, food restriction dramatically increased rats' open-arm exploration in the plus-maze. By contrast, food restriction did not alter the duration of time rats spent burying an electrified probe in the shock-probe burying test. Furthermore, food restricted rats displayed increases in risk assessment behaviour in both tests. Animals’ behaviour in both animal models of anxiety does not suggest a food-restriction induced reduction in anxiety. Alternatively, the results suggest that rats' willingness to explore normally avoided open arenas is sensitive to their current energy demands. In particular, it appears that under conditions of food scarcity rodents adapt their defensive profiles in order to meet both safety needs and satisfy energy demands. Further, the dramatic shift in open-arm exploration displayed by food-restricted animals seems to involve activation (as indexed by cFos) of brain regions previously implicated in feeding behaviour and normal open arm avoidance. Notably, an interaction effect of feeding and testing was observed in the anterior basolateral amygdala. This nucleus may be involved in integrating the competing demands of safety and energy requirements. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2008-09-18 16:58:44.385

No description available.