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Thesis (Ph.D.) -- McMaster University, 2000. / Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.) -- McMaster University, 2000. / Includes bibliographical references. Also available via World Wide Web.

This study was carried out over three breeding seasons at a small marsh-nesting black-headed gull (Larus ridibundus) colony. Two of the years proved to be atypically hot and dry, resulting in the drying out of parts of the colony. This facilitated predation by foxes and resulted in almost complete breeding failure in these two years. Synchronisation of breeding was evident but the average clutch size was smaller than generally recorded for black-headed gulls. There was a tendency for third laid eggs and third hatched chicks to have the highest mortality rate, and third hatched chicks put on less weight during their first three days of life than all other chicks. Pairs of gulls that did not successfully retain their territories and lay eggs spent less time on the territory than those that were successful. The unsuccessful males were also more restless and more aggressive than successful males. In general, the gulls spent most time on the territory during the incubation stage, although partners spent the most time together on the territory during the pre-egg stage. The territory was never left unattended during the incubation stage, but it was occasionally deserted during the pre-egg stage, and increasingly deserted as the chick stage proceeded. In one year, but not another, males spent most time on the territory and incubating during the egg stage, while females spent most time on the territory and brooding during the chick stage. The gulls were most aggressive during the pre-egg stage and least aggressive during the incubation stage, and the males played the greater role in defence during the pre-egg and egg stages. The sexes shared equally the feeding of the chicks and became less eager to feed the chicks as they grew. The number of feeds given per hour per chick decreased with increasing brood size.

No / This paper presents a numerical investigation into the behaviour of headed shear stud in composite beams with profiled metal decking. A three-dimensional finite element model was developed using general purpose finite element program ABAQUS to study the behaviour of through-deck welded shear stud in the composite slabs with trapezoidal deck ribs oriented perpendicular to the beam. Both static and dynamic procedures were investigated using Drucker Prager model and Concrete Damaged Plasticity model respectively. In the dynamic procedure using ABAQUS/Explicit, the push test specimens were loaded slowly to eliminate significant inertia effects to obtain a static solution. The capacity of shear connector, load-slip behaviour and failure modes were predicted and validated against experimental results. The delamination of the profiled decking from concrete slab was captured in the numerical analysis which was observed in the experiments. ABAQUS/Explicit was found to be particularly suitable for modelling post-failure behaviour and the contact interaction between profiled decking and concrete slabs. It is concluded that this model represents the true behaviour of the headed shear stud in composite beams with profiled decking in terms of the shear connection capacity, load-slip behaviour and failure modes.

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Thesis (M.A. (Psychology)) -- University of Limpopo, 2016 / The aim of the present study was to explore and describe the psychosocial experiences of secondary school learners from child-headed households in Mankweng area, Limpopo province. A qualitative research approach, specifically the phenomenological research design was used in this study. Ten grade 8 to 10 learners (male = 5; female = 5), aged between 16 and 18 years were purposively selected and requested to participate in the study. Data were collected through structured interviews. The Interpretative Phenomenological Analysis (IPA) method was used to analyse the data. The following three categories of themes were identified: a). Circumstances leading to child-headed households; b). Socioeconomic themes category; and, c). Psychosocial themes category. Each of the three categories yielded a number of themes. There were nine psychosocial category themes that emerged from the data. These among others included the following: a). Poor scholastic performance by learners from child-headed families; b). Increased levels of sexual abuse and teenage pregnancy for the girl child; and, c). Psychosocial trauma. With regard to coping strategies, the study found that girls tended to engage in risky sexual behaviour as a way to access financial support and to cope with their challenges when compared to boys who tended to engage in more positive behaviour like garden work in order to earn a living. Based on the above findings, the study recommends that learners from child-headed households should receive counselling support from school based support teams. Special consideration should be given to the orphaned girl child who is more vulnerable to psychosocial risks when compared to a boy child from a similar family background. The study further recommends that community support centres be established in order to support learners from child-headed families with after-school care, meals and recreational activities. There is also a need for community forums to be established and to prioritise the safety of their neighbourhoods in order for all children to feel appreciated and safe in their environments. The Department of Social Development should also continue to provide the support grant to learners who have reached the age of 18 who live in child-headed households as they still need care and support.

The biology of the Grey-headed Gull was studied between 2004 and 2005 in South Africa's Gauteng, KwaZulu-Natal and Northern Cape provinces. Grey-headed Gulls have a widespread but patchy distribution in South Africa, occurring both inland and at the coast. Their largest population is centred on Gauteng, where the species appears to be a relatively recent colonizer and where the current breeding population is estimated at 2185 breeding pairs (the largest in South Africa). There is evidence that the species has also increased in other parts of South Africa, especially at Port Elizabeth in the Eastern Cape. The majority of coastal birds are found in KwaZulu-Natal and there is strong evidence for regular movements of adult birds between Durban and Lake St Lucia. By contrast, little evidence was found for a putative large-scale, regular movement between Gauteng and KwaZulu-Natal. The breeding biology of the Grey-headed Gull was studied at four sites in Gauteng and at Lake St Lucia's Lane Island during 2004 and 2005. The distance between the Gauteng sites ranges from 1.7 km, between Lakefield Pan and Korsman's Bird Sanctuary, to 25.3 km, between Bonaero Park and Modderfontein Pan. The approximate distance between Gauteng and Lake St Lucia is 460 km. The mean clutch size at all sites was 2.42 eggs and the mean incubation period was 24.9 days. Parental investment in incubation was approximately equal between the sexes while males spent more time in attendance and participated in more aggressive encounters. Empirical growth curves are given for mass, wing, culmen, head and foot morphometrics of Grey-headed Gull chicks. Intraspecific variation in breeding parameters reveal significant differences between sites, including: highly synchronous laying at Lake St Lucia; the largest eggs and fastest growing chicks at Gauteng's Modderfontein Pan (a small, peripheral colony); and the smallest eggs and slowest growing chicks at Gauteng's Lakefield Pan (a large, 'core' colony). Possible reasons for these differences include the relative localities of each site in terms of feeding opportunities, high levels of predation by African Fish Eagle's at Lane Island, and density dependent factors operating on the large colonies within the core population on Gauteng's East Rand. Overall daily egg survival was comparatively high for all sites in Gauteng and low for Lane Island nests. Morphometric, plumage and bare-parts data from a sample of trapped and resighted birds are used to age, sex and determine the timing and duration of moult in the Greyheaded Gull. Six age classes were identified and, for all measurements, males were significantly larger than females. The mean duration of primary moult was 136 days between October and January and there were two waves of secondary moult. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

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