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Quantitative genetics has traditionally been used to examine selection responses in domesticated organisms, but has recently been applied by evolutionary biologists to natural populations. Evolutionary biologists use quantitative genetics to model variation in traits related to fitness and, ultimately, to make predictions about the impact of natural selection on populations. However, there are few cases in which quantitative genetics has been used to predict changes in natural populations, and only two cases in which it has been used to predict a correlated response to natural selection. / I use a quantitative genetic model to predict the correlated response to natural selection in geographically distinct wild populations of the wing dimorphic sand cricket, Gryllus firmus. Three populations of G. firmus that naturally vary in proportion macroptery are used to qualitatively assess, for the first time, predictions from a quantitative genetic model postulating that an increase in proportion macroptery is correlated with a decrease in fecundity. Variation observed among the populations when raised in a common garden supports predictions and demonstrates that a difference in mean fecundity is the result of a response in fecundity within wing morphs in addition to a change in the proportion of macropterous females. My results indicate that the complexity behind evolutionary changes in traits genetically correlated with proportion macroptery can be modeled through quantitative genetics.

This thesis explores three fundamental issues in the phonology and morphology of Ethiopian Semitic languages: mobile morphology, reduplication and epenthesis. In each chapter I draw on comparative evidence from different Ethiopian Semitic languages, an approach which provides greater insight into how the languages vary with respect to these three issues, and how the issues themselves are best analyzed. / The first issue is that of 'mobile morphology' a term I coin to describe the ability of a particular morphological category to be realized on various segments within a stem. The two major types in the South Ethio-Semitic languages are palatalization and labialization. I develop an analysis of palatalization in five different languages which relies on a hierarchy of preferred targets, along with a number of constraints regulating the appearance of palatalization within the stem. / Ethio-Semitic languages have several different types of reduplication. I draw a distinction between phonological and morphological reduplication and argue that phonological reduplication should be viewed as copying rather long-distance geminate structures created by spreading. I also examine the interaction of reduplication with mobile morphology and I present an analysis of double reduplication, showing how languages will avoid the creation of double reduplication relationships. / I develop an analysis of epenthesis which contrasts the behaviour of one set of languages which epenthesize following final consonant clusters with other languages which epenthesize between consonant clusters. I show that while all Ethio-Semitic languages follow the same general pattern, this may be overridden by templatic constraints and more importantly, by sonority considerations holding of adjacent syllables in coda-onset sequences. This last observation is important because it shows that while languages may on the whole violate heterosyllabic contact constraints, in particular circumstances, the constraints will be obeyed, giving rise to an emergence of the unmarked scenario.

Pre-eclampsia, often described as toxaemia of pregnancy, historically represents one of the most widely investigated conditions relating to human reproduction. To date no firm cure has been found and a clear, well defined mechanism has not been ascribed to the pathogenesis of the disease. Researchers seem to focus on single pathways in isolation of others. The disease rather represents a multitude of possible underlying pathologies nvolving genetics, immune dysregulation, vascular maladaptation, and sociobiological factors thus complicating the approach to treatment. However, a central theme is the presence of reduced placental perfusion resulting in a hypoxic and/or ischaemic placenta and the subsequent secretion of various factors that initiate the maternal syndrome. It is within this context that we examine how an intervention such as increasing placental perfusion may represent a promising treatment strategy for this disease. We sought to manipulate the vasodilatory mechanisms of the uterine vasculature using sildenafil citrate and a flavonoid extracted from Eriosema kraussianum (Kr2), in Sprague-Dawley rats that exhibited preeclampsia-like manifestations. Both treatment regimens improved fetal outcomes and reduced blood pressure amplification and proteinuria. They also reduced the plasma concentrations of the two anti-angiogenic factors; sFlt1 and sEng. Only sildenafil citrate improved nitric oxide levels which was expected, suggesting that Kr2 causes vasodilation by some other mechanism. Nevertheless, both compounds improved both pup and placental weights, suggesting that they also improve utero-placental perfusion. These findings that selective uterine vascular dilation improves placental perfusion may be promising in averting possible death to mothers and their babies from pre-eclampsia especially in low resource environments. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2011.

Adequate maternal, intervillous and fetal blood flow are all necessary for fetal wellbeing. Compromise to any part of this exchange would be detrimental to pregnancy outcome. Preeclampsia is associated with reduced maternal spiral artery flow, resulting in reduced placental perfusion. This in turn creates an ischemic environment which may pre-dispose morphological changes in placental villi. This pilot study utilized morphometric image analysis to examine some features of the fetal component of the placenta in normotensive (NT) and pre-eclamptic (PE) groups. The features examined included: density of placental villi (expressed as percentage of field area occupied by placental tissue); stem vessel carrying capacity (expressed as percentage of stem villus area occupied by vessel lumina); the thickness of the stem arterial walls relative to artery size (expressed as percentage of artery area occupied by arterial wall) and the extent of fibrosis associated with villi (expressed as percentage of field area occupied by fibrosis). The results were as follows: density of placental villus arrangement NT:51.89±6.19, PE:64.78±6.93 (P<0.001); carrying capacity of stem villi NT:17.20±11.78, PE:8.67±8.51 (P<0.001); relative thickness of stem villi arterial walls NT:74.08±12.92, PE: 86.85±10.55 (P<0.001); and extent of fibrosis NT:0.727±0.310, PE:1.582±0.707 (P<0.001). These significant differences between normotensive and pre-eclamptic placentae suggest possible fetal maladaptations in response to the intervillous ischemia, compounding the existing maternal compromise to materno-fetal exchange. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2012.

Downstream adjustment in stream channel morphology is examined in the context of stream channel confluences. Stream channel confluences represent areas of point specific increases in discharge, flow energy and potential erosion in a river system which will in turn affect the post-confluence downstream morphology. Analysis of 12 confluence junctions from southern Ontario streams, constituting 36 channel reaches in total, show an internally consistent hydraulic geometry relationship but with specific controls on channel morphology related to boundary conditions. Predictions of mainstem morphologies is possible using tributary attributes but reach specific channel confinement and material type add significant influence.

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