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The life-history traits of two sympatric seabird species, the Common Sterna hirundo and Arctic Tern S. paradisaea, and the flexibility of these traits in relation to short and longer term changes in environmental conditions were measured at Coquet Island, N.E. England. The study focused primarily on inter and intraspecific differences in annual productivity and chick growth, adult time budgets and provisioning rates, and the relationships between these different aspects of reproductive performance. Of the two species, Common Terns delivered larger food items, delivered food at a higher rate to the nest and attended the nest more frequently, indicating that they made trips of shorter average duration. Daily metabolizable energy intake of chicks was about 30% higher in Common Terns than in Arctic Terns, yet the size-specific growth rates of the two species were almost identical, indicating a major difference between species in nestling energy budgets. Brooding appeared to play a less important role in the energy budgets of Common Terns, and the number of chicks that Arctic Terns could raise was probably limited not only by the rate at which parents could supply food to the nest but also by the requirements of chicks for brooding. Increased brood size, low annual food abundance and extreme weather conditions had a negative effect on chick mass development in both tern species. Flexibility of mass growth rates in Arctic and Common Terns may act as a fine-tuning mechanism to regulate provisioning in these species. By maintaining structural growth rates, final fledging mass and final fledging size of nestlings at the expense of retarded mass development rates, these species seem to be able to maximize annual reproductive output and possibly, for parents and nestlings, future survival. Predation of eggs and chicks was generally infrequent and affected mostly very young nestlings. However, Black-headed Gulls took many tern eggs in a year when inshore food supplies were particularly low.

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This thesis deals with electrical conductivity in thin films. Classical and quantum size effects in conductivity are discussed including some experimental evidence of quantum size effects. The component conductivity along the applied electric field of a thin film in a transverse magnetic field is developed in a density matrix method.

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Rho Kinase (Rho-K) has been implicated in the pathophysiology of many deleterious conditions and its inhibition was shown to ameliorate these compromising effects. It is unclear; however, whether inhibition of Rho-K would decrease infarct size in hearts after ischemia/reperfusion. Adult ICR mice were randomized to 1 of 4 treatments: saline, fasudil (Rho-K inhibitor (10 mg/kg i.p.), Fasudil+L-NAME (Nitric Oxide synthase inhibitor, 15 mg/kg), and L-NAME. Hearts were isolated, perfused in Langendorff mode and subjected to 30 min stabilization before 30 min ischemia and 60 min reperfusion. Left ventricular (LV) function was monitored. Hearts were stained and infarct size measured. Fasudil reduced infarct size as compared with control hearts; however, this protective effect was abolished by L-NAME. LV function mirrored these trends. The loss of cardioprotection after L-NAME administration indicates that cardioprotection by Rho-K inhibition is mediated through nitric oxide-dependent pathway. Furthermore, Fasudil administration at and throughout reperfusion showed similar cardioprotection.

Master of Science / Department of Statistics / Paul Nelson / Effect size is a concept that was developed to bridge the gap between practical and statistical significance. In the context of completely randomized one way designs, the setting considered here, inference for effect size has only been developed under normality. This report is a simulation study investigating the robustness of nominal 0.95 confidence intervals for effect size with respect to departures from normality in terms of their coverage rates and lengths. In addition to the normal distribution, data are generated from four non-normal distributions: logistic, double exponential, extreme value, and uniform. The report discovers that the coverage rates of the logistic, double exponential, and extreme value distributions drop as effect size increases, while, as expected, the coverage rate of the normal distribution remains very steady at 0.95. In an interesting turn of events, the uniform distribution produced higher than 0.95 coverage rates, which increased with effect size. Overall, in the scope of the settings considered, normal theory confidence intervals for effect size are robust for small effect size and not robust for large effect size. Since the magnitude of effect size is typically not known, researchers are advised to investigate the assumption of normality before constructing normal theory confidence intervals for effect size.

Doctor of Philosophy / Division of Biology / Mark C. Ungerer / Nuclear genome size varies immensely across flowering plants, spanning nearly 2400-fold. The causes and consequences of this vast amount of variation have intrigued biologists since it became clear that nuclear DNA amount did not reflect organismal complexity (the so-called C-value paradox). In my dissertation I utilize wild sunflower species in the genus Helianthus to examine the role of transposable elements (TEs), and in particular, long terminal repeat (LTR) retrotransposons, in generating genome size variation and whether variation in genome size influences aspects of plant growth and development across multiple organizational levels. The genus Helianthus provides an excellent system for studying these questions given four-fold variation in nuclear DNA content among diploid species and well-resolved phylogenetic relationships. Utilizing short-read Illumina data and sequence information from a diverse panel of Helianthus annuus (common sunflower) full-length LTR retrotransposons, I found that nuclear genome size in Helianthus species is positively correlated with repetitive DNA, and LTR retrotransposon subtypes generally show similar patterns in genomic abundance across taxa. Helianthus species with the largest genomes, however, exhibit large-scale amplification of a small number of LTR retrotransposon subtypes. Measuring aspects of plant growth and development at cell-, organ- and whole plant-levels in a panel of diploid Helianthus species that vary 4-fold in nuclear genome size, I found that genome size is negatively correlated with cell production rate, but that this negative correlation does not persist at higher organizational levels. Taken together, these results provide insights into the mechanisms contributing to genome size evolution in plants and the organizational level at which genome size may impact growth patterns and developmental rates. Genome expansion in wild sunflowers is influenced most significantly by amplification of a small number of TEs and not necessarily by a greater diversity of TEs. Genome size is strongly negatively correlated with cell production rate but this relationship weakens at higher organizational levels, such as that of organ and whole-plant development.

Object-Oriented design and development dominates both commercial and open source software projects. One of the principal goals of object-oriented design is to aid reuse, and hence, reduce future maintenance efforts of software systems. However, the on-going maintenance of large-scale software systems (both changes and faults) continues to be a significant proportion of the lifecycle of the system and the total investment cost. Understanding and thus being able to predict - or even reduce - the impact of the contributing factors of future maintenance efforts of a software system is thus highly beneficial to software practitioners. In this Thesis we empirically study a large, commercial software system with the principal aim to determine the contributing factors to the change and fault propensity over a three-year period. We consider the object-oriented design context of the software, specifically its inheritance characteristics, coupling and cohesion properties, object-oriented design pattern participation, and size. We also explore the effect of refactoring and test classes in the software. Our results show that several aspects of the design context of a class have an impact to the change and fault-proneness of the software. Specifically, we show that classes with high afferent or efferent coupling are more change and fault-prone; we also identify a number of design patterns whose participants tend to have a higher change and fault propensity than non-participants and we identify a range of inheritance characteristics (in terms of depth of inheritance and number of children) that result in an increase to change and fault-proneness. Furthermore we show that refactoring is a commonly occurring maintenance activity, although it is largely limited to simpler types of refactorings. Finally, we provide some insight into the co-evolution of production and test code during refactoring.

MSc (Eng), Faculty of Engineering and the Built Environment, University of the Witwatersrand, 2011 / Most of the remaining coalfields in South Africa are found in arid areas where process water is scarce and given the need to fully exploit all the coal reserves in the country, this presents a great challenge to the coal processing industry. Hence, the need to consider the implementation of dry coal beneficiation methods as the industry cannot continue relying on the conventional wet processing methods such as heavy medium separation. Dry coal beneficiation with an air dense-medium fluidized bed is one of the dry coal processing methods that have proved to be an efficient separation method with separation efficiencies comparable those of the wet heavy medium separation process. Although the applications of the fluidized bed dry coal separator have been done successfully on an industrial scale, the process has been characterized by relatively poor (Ecart Probable Moyen), Ep values owing to complex hydrodynamics of these systems. Hence, the main objectives of this study is to develop a sound understanding of the key process parameters which govern the kinetics of coal and shale separation in an air fluidized bed focusing on the effect of the particle size, shape and density on the performance of the fluidized separator as well as developing a simple rise/settling velocity empirical model which can be used to predict the quality of separation. As part of this study, a (40 x 40x 60) cm air fluidized bed was designed and constructed for the laboratory tests. A relatively uniform and stable average bed density of 1.64 with STDEV < 0.01 g/cm3 was achieved using a mixture of silica and magnetite as the fluidizing media. Different particle size ranges which varied from (+9.5 -16mm), (+16 -22mm), (+22 -31.5mm) and (+37 -53mm) were used for the detailed separation tests. In order to investigate the effect of the particle shape, only three different particle shapes were used namely blockish (+16 -22mm Blk), flat (+16 -22mm FB) and sharp pointed prism particles (+16 – 22mm SR).Different techniques were developed for measuring the rise and settling velocities of the particles in the bed. The Klima and Luckie partition model (1989) was used to analyze the partition data for the different particles and high R2 values ranging from (0.9210 - 0.9992) were recorded. Average Ep iii values as low as 0.05 were recorded for the separation of (+37 -53mm) and (+22 -31.5mm) particles under steady state conditions with minimum fluctuation of the cut density. On the other hand, the separation of the (+16 -22mm) and (+9.5 – 16mm) particles was characterized by relatively high average Ep values of 0.07 and 0.11 respectively. However the continuous fluctuation or shift of the cut density for the (+9.5 -16mm) made it difficult to efficiently separate the particles. Although, particle shape is a difficult parameter to control, the different separation trends that were observed for the (+16 -22mm) particles of different shapes indicate that particle shape has got a significant effect on the separation performance of the particles in the air fluidized bed. A simple empirical model which can be used to predict the rise/settling velocities or respective positions of the different particles in the air fluidized bed was developed based on the Stokes’ law. The proposed empirical model fitted the rise/settling data for the different particle size ranges very well with R2 values varying from 0.8672 to 0.9935. Validation of the empirical model indicate that the model can be used to accurately predict the rise/settling velocities or respective positions for all the other particles sizes ranges except for the (+9.5 – 16mm) particles where a relatively high average % error of (21.37%) was recorded. The (+37 -53mm) and (+22 -31.5mm) particles separated faster and more efficiently than the (+16 -22mm) and (+9.5 -16mm) particles. However, the separation efficiency of the particles can be further improved by using deeper beds (bed height > 40cm) with relatively uniform and stable bed densities. Prescreening of the coal particles into relatively narrow ranges is important in the optimization of dry coal beneficiation using an air fluidized bed since different optimum operating conditions are required for the efficient separation of the different particle size ranges and shapes. The accuracy and the practical applicability of the proposed empirical model can be further improved by carrying out some detailed rise/settling tests using more accurate and precise equipment such as the gamma camera to track the motion of the particles in the fluidized bed as well as measuring the actual bed viscosity and incorporate it in the model.