This study is centred on the phenomenon of the child headed household in Rwanda. Such households have become an increasingly common occurrence in Sub-Saharan Africa, as a result, in particular, of the HIV/AIDS pandemic. This has caused millions of children to become orphaned, and has brought about new coping mechanisms. The case of Rwanda, however, differs from the majority of countries which have experienced the emergence of these households. Its uniqueness lies in the fact that its child headed households are a legacy of two major factors, that of genocide as well as HIV/AIDS. The genocide of 1994 resulted in the death of an estimated 800,000 people, and prompted mass displacement and estrangement of the majority of the population. There has been considerable interest in Rwanda‟s progress following the genocide on the part of academics, NGOs and development practitioners. Whilst some of this has focused on children and the vulnerable, the long term perspective has not been sufficiently considered. This research set out to address this by undertaking a longitudinal study over four years examining the child headed household in Rwanda. A core group of 42 households formed the sample, taken from urban, peri-urban, and rural areas and from a refugee camp. In the first place the study explores the definition of “child headed household” and offers a typology of the phenomenon. Second, it offers an analysis based on field work of the livelihood challenges to the children within these households, including the basic survival needs of land and property inheritance, income generation and education. Finally the psychosocial needs of the child headed households for acceptance and participation within communities were considered. This work considers the challenges to livelihood survival and the non-material needs of those in child headed households in Rwanda within the realities of daily life. It concludes that child headed households need to be redefined in terms of age, composition, and their particular narratives, and their variable composition is an integral characteristic. The livelihood needs of CHHs are particularly challenged by the lack of opportunities for income generation, access to land rights and changes in household life, including revisions in programmes and policies. Furthermore the non-material needs of the children in these households are often unacknowledged; their stories frequently portray a lack of family and community support, marginalisation and isolation, which contests widely held and historic understandings of family and community.

In this study the learning challenges faced by Black orphaned girl learners in the Xhariep District who head households, were explored. A literature study was undertaken to highlight the causes, magnitude and effects of child-headed households and to establish the learning challenges in general experienced by learners who head households. Important prerequisites for effective learning such as parental expectations, self-esteem, goal orientation, school attendance, positive attributions, motivation, need fulfilment, self-regulation, self-efficacy, cognitive development, parental involvement and socio-economic factors were explored. The literature review informed the conceptual framework of the study, and provided the framework for designing interview questions that were used to gain a deeper understanding of the learning challenges experienced by black girl learners who head households. By means of qualitative, phenomenological research, one-on-one interviews were conducted with a convenient sample of a purposively selected group of 10 Black girl learners at Secondary School Level who head households in the Xhariep District of the Free State Department of Education. The interpretation of the data revealed various learning challenges which are experienced by these learners due to their unfavourable circumstances as heads of households. The interview data revealed that the girls who take part in the study experience a lack of basic needs such as food and money and love and belonging. Furthermore, they experience emotional problems due to the death of their parents and the stressful situation of having the cope with numerous responsibilities at home and school. Due to the mentioned problems, the participants experience learning challenges related to irregular school attendance, difficulty in coping with and concentrating on their schoolwork, poor achievement and low self-esteem. According to the responses of the learners, it is difficult to be a child and a parent at the same time, having to account for all the responsibilities of being a learner and accomplishing the parental role. This study is concluded with recommendations to teachers on how to assist Black girl learners who head households in the Xhariep District. / MEd, Learning and Teaching, North-West University, Vaal Triangle Campus, 2011

Monte Carlo simulations have been used in the past to investigate a variety of surfactant systems; however, there is little published literature for double-headed and gemini surfactants with asymmetric tails. We perform Larson-type Monte Carlo simulations of double-headed and gemini surfactant systems with asymmetric tails in two- and three-dimensions. The model predicts that the addition of a second head group to form a double-headed surfactant results in an increase in the critical micelle concentration (CMC) compared to a single-headed surfactant, in agreement with experiment. It also indicates that the placement of the second head group has an impact on the final CMC value. We study a series of gemini surfactants with asymmetric tails and find no change in the value of the CMC as the ratio of the lengths of the two tails increases. This is contrary to the only experimental study that found there was a slight decrease in the CMC as the ratio of the lengths of the two tails increases. We examine this difference in terms of the relatively small effect surfactant asymmetry has on value of the CMC and the fact that the model is capable of qualitatively reproducing the known dependence of the CMC on other architectural properties. This initial probe into systems of double-headed and gemini surfactants with asymmetric tails confirms many of the previously published findings and provides avenues for possible future research using Monte Carlo simulations.

In this study the learning challenges faced by Black orphaned girl learners in the Xhariep District who head households, were explored. A literature study was undertaken to highlight the causes, magnitude and effects of child-headed households and to establish the learning challenges in general experienced by learners who head households. Important prerequisites for effective learning such as parental expectations, self-esteem, goal orientation, school attendance, positive attributions, motivation, need fulfilment, self-regulation, self-efficacy, cognitive development, parental involvement and socio-economic factors were explored. The literature review informed the conceptual framework of the study, and provided the framework for designing interview questions that were used to gain a deeper understanding of the learning challenges experienced by black girl learners who head households. By means of qualitative, phenomenological research, one-on-one interviews were conducted with a convenient sample of a purposively selected group of 10 Black girl learners at Secondary School Level who head households in the Xhariep District of the Free State Department of Education. The interpretation of the data revealed various learning challenges which are experienced by these learners due to their unfavourable circumstances as heads of households. The interview data revealed that the girls who take part in the study experience a lack of basic needs such as food and money and love and belonging. Furthermore, they experience emotional problems due to the death of their parents and the stressful situation of having the cope with numerous responsibilities at home and school. Due to the mentioned problems, the participants experience learning challenges related to irregular school attendance, difficulty in coping with and concentrating on their schoolwork, poor achievement and low self-esteem. According to the responses of the learners, it is difficult to be a child and a parent at the same time, having to account for all the responsibilities of being a learner and accomplishing the parental role. This study is concluded with recommendations to teachers on how to assist Black girl learners who head households in the Xhariep District. / MEd, Learning and Teaching, North-West University, Vaal Triangle Campus, 2011

Existing gender inequality is believed to be heightened as a result of weather events and climate-related disasters that are likely to become more common in the future. We show that an already marginalized group-female-headed households in South Africa-is differentially affected by relatively modest levels of variation in rainfall, which households experience on a year-to-year basis. Data from three waves of the National Income Dynamics Survey in South Africa allow us to follow incomes of 4,162 households from 2006 to 2012. By observing how household income is affected by variation in rainfall relative to what is normally experienced during the rainy season in each district, our study employs a series of naturally occurring experiments that allow us to identify causal effects. We find that households where a single head can be identified based on residency or work status are more vulnerable to climate variability than households headed by two adults. Single male-headed households are more vulnerable because of lower initial earnings and, to a lesser extent, other household characteristics that contribute to economic disadvantages. However, this can only explain some of the differential vulnerability of female-headed households. This suggests that there are traits specific to female-headed households, such as limited access to protective social networks or other coping strategies, which makes this an important dimension of marginalization to consider for further research and policy in South Africa and other national contexts. Households headed by widows, never-married women, and women with a non-resident spouse (e.g., "left-behind" migrant households) are particularly vulnerable. We find vulnerable households only in districts where rainfall has a large effect on agricultural yields, and female-headed households remain vulnerable when accounting for dynamic impacts of rainfall on income.

<p>  </p> <p>The use of headed reinforcement in concrete has found an increasing interest in construction applications. From shear reinforcement in walls to longitudinal reinforcement in beams and columns, there is a growing need to understand the behavior of headed rebars. A headed rebar is a deformed bar with a head attached to its end and while similar anchorage devices such as headed studs and hooked rebars are well established in theory with design equations developed, headed reinforcement lack this level of knowledge and hence, their application in industry is limited.</p> <p>Current code provisions such as fib Model Code 2010 allow the design of headed rebars as (1) a hooked bar, (2) a headed stud, and (3) using experimental results. Moreover, ACI 318-19 only contains a design equation for the development length of headed rebars but not its capacity. While the literature has justified the approximation of the capacity of headed rebars with hooked bars through a multitude of studies comparing both anchorage devices. Such a justification is not well-founded for headed studs due to a scarcity of studies comparing headed rebars to headed studs. Moreover, there is a lack of design equations accurately predicting the behavior of headed rebars in several parameters. All these issues emanate from the complexity of headed rebars due to their joint mechanism of anchorage coming from both resistance along the rebar deformations and bearing on the head.</p> <p>This study aims to better understand the behavior of headed bars by numerically analyzing the influence of different parameters on their performance. Furthermore, direct comparisons are made between headed reinforcement, headed studs, and straight bars to segregate the effect of the bond along the shaft and the bearing at the head on the behavior of headed bars. </p> <p>The parameters included in this study are embedment depth, edge distance, and concrete compressive strength. The numerical models are verified using a 3D non-linear finite element software MASA (Macroscopic Space Analysis) which employs the microplane model with relaxed kinematic constraint as the constitutive laws of concrete. Two numerical approaches, which differ only in the interface properties between the head and concrete, are validated against experimental results before carrying out the parametric study. Several properties including head, concrete, and bond stresses, along with ultimate capacities and crack patterns are extracted from the models and analyzed. Moreover, the load-displacement graphs of headed rebars, studs, and straight rebars are compared and contrasted. Assessments and theories about the discrepancies between the behavior of headed studs and rebars are stipulated. Finally, potential methods for formulating design equations are proposed for future studies.</p>

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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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<p> The mtDNA control region of the Brown-headed Cowbird (Molothrus ater) was sequenced and comparisons made at the inter- and intraspecific level. Comparison of the control region with that of another Passerine, Darwin's Finch (Geospiza scandens), revealed a high degree of both gross and fine scale structural similarity. At the nucleotide level, this comparison confirmed the presence of a hypervariable domain which evolves at rate approximately 5 times faster than coding mtDNA as well as a relatively conserved central domain which evolves at rate comparable to coding mtDNA. Both species displayed the typical avian mtDNA gene organisation previously described by Desjardins and Morais (1990, 1991) and Quinn and Wilson (in press). However, the most notable structural feature in common was the apparent deletion of the entire left hypervariable domain (CR1). At a finer scale, Conserved Sequence Block (CSB1) was perfectly conserved between cowbird and finch and Conserved Sequence Block 2 (CSB2) was 78% similar. The hypervariable right domain showed the largest degree of sequence divergence between species, 22.7%, while the central domain and phe-tRNA showed much less divergence, 6.47 and 4.41% respectively. At an intraspecific level, in 524 bases of sequence from 31 nestling cowbirds from a population at Delta, Manitoba, only 3 variable sites were detected which defined a total of 4 haplotypes. The average percent sequence divergence for this population was 0.27%. This level of variation within the cowbird population is low compared to other vertebrate populations. This relative lack of variation is largely attributable to the loss of the left hypervariable domain (CR1). The loss of CR1 will limit the control region's usefulness for high resolution population level studies but may make it a useful marker for phylogenetic studies within the class Aves.</p> / Thesis / Master of Science (MSc)