ABSTRACT Ehrharta calycina J. E. Sm. (Poaceae) is a widespread and often abundant species whose core distribution lies within the Greater Cape Floristic Region (GCFR). Importantly, it shows a high degree of morphological and ploidy level variation. Based on observations of distinct forms co-occurring at multiple sites, the hypothesis that E. calycina comprises more than one species was tested. Morphological analysis of herbarium specimens using a multivariate approach found strong evidence fo...
Abstract This study investigates the diet of breeding Black Sparrowhawks (Accipiter melanoleucus) on the Cape Peninsula of South Africa. Macro-remains of prey were collected from below and around the vicinity of nests throughout the breeding seasons of 2012 and 2013. These prey items were then identified down to species where possible through the use of a museum reference collection. In both years 85.9% of the individual remains were those of Columbidae, which corresponds with the only other ...
Abstract Interest in commercial sea urchin aquaculture is growing worldwide. This is because sea urchins have good quality roe which is a delicacy in many countries. Since the quality of sea urchin roe is dependent on what the sea urchin eats, increased research is being carried out to understand sea urchin feeding preferences. Feeding preference is related to the attractiveness/palatability of the feed, which is thought to be based on its chemical composition. Since an unpalatable feed will ...
Abstract Phytoplankton community composition in the Southern Ocean (SO) determines levels of primary production, which support marine ecosystems and export of material to the deep sea. Nanoplankton (cell diameters 2-20 µm) are poorly resolved by traditional microscopy, and it is becoming apparent that unknown diversity and ecosystem functionality may be contained in this size class: for example, small diatoms (
Table of Content Acknowledgment Short Abstract General Abstract Chapter 1: Introduction Chapter 2: Stable isotope turnover in blood and toenails: A case study in captive African penguins Chapter 3: Insights from stable isotope into African penguins foraging behaviour during the pre-moult period Chapter 4: Temporal and spatial variation of Cape Gannet diets: lessons from stable isotopes Chapter 5: The pattern and location of moult in White-chinned Petrels Chapter 6: White-chinned Petrel...
Abstract Within the Cape Floristic Region many lineages are characterised by large floral diversity. The genus Erica is one of these lineages, making up -7% of the CFR. Surprisingly, even though pollinators have been suggested to be a driving force of floral morphology, the role of pollinators in the floral diversification and speciation of this genus is not yet well understood. Therefore the aim of this paper was to establish if Erica species can and do self-pollinate. Two Erica ...
ABSTRACT The yeast Saccharomyces cerevisiae is used extensively in many important industrial applications that often expose these organisms to a range of stresses. Consequently, a considerable amount research has focused on understanding the nature of stress response in yeast and the development of more stress resistant yeast. The stress protein Hsp12 has since garnered interest, as it is upregulated in response to a wide variety of environmental stresses. Using an Hsp12-GFP construct, we con...
Abstract The disturbance ecology and regeneration patterns of the emergent conifer, Widdringtonia whytei, and five broadleaved species, Aphloia theiformis, Rapanea melanophloeos, Maesa lanceolata, Maytenus accuminata and Psychotria mahonii, were inferred from population size structures in the mixed conifer-broadleaved forests of Mt. Mulanje, Malawi. The size-class structures of the emergent cedar populations were characterised by even-sized, disjunct frequency distributions. Seedling recruitm...
ABSTRACT Over the years, natural products have played a major role in the search for novel drugs or drug candidates. Secondary metabolites from nature especially those of fungal origin exhibit unique biological activities and research continue to meet the keen interests which have potential pharmaceutical value. Fungi constitute an important source of secondary metabolites such as penicillin. The present study analyzed the biological activities of a variety of compound mixtures from wood deca...
Dynamic Bayesian Networks (DBNs) are temporal probabilistic models for reasoning over time. They often formulate the core reasoning component of intelligent systems in the field of machine learning. Recent studies have focused on the development of some DBNs such as Hidden Markov Models (HMMs) and their variants, which are explicitly represented by highly skilled users and have gained popularity in speech recognition. These varieties of HMMs represented as DBNs have contributed to the baselin...
Abstract In this thesis, we develop the 1 + 1 + 2 formalism, a technique originally devised for General Relativity, to treat spherically symmetric spacetimes in for fourth order theories of gravity. Using this formalism, we derive equations for a static and spherically symmetric spacetime for general f(R) gravity. We apply these master eqautions to derive some exact solutions, which are used to gain insight on Birkhoff's theorem in this framework. Additionally, we derive a covariant form of t...
ABSTRACT Recent demographic dynamics have revealed a dramatic shift in the world’s population, manifesting for the first time ever, more than half of all the world’s population living in urban areas, with 2008 being the transition year. Ghana is not an exception, as its urban centres continue to experience unprecedented growth. Although cities are focal points for development, they equally potentiate the accumulation of risks if not managed properly. The objective of the study therefore i...
Abstract This study concerns the application of a model-based approach for problem solving and conceptual understanding, in the context of kinematics, relating to the “foundation” component of an introductory physics course designed for students who are academically and scientifically underprepared. A new method for portraying objects in motion, “freeze frame” representation, was introduced. The particular visual conceptual model was employed as a representational bridge for translati...
Abstract This thesis investigates the impacts of the demersal trawl fishery on infaunal, epifaunal and fish assemblages in the southern Benguela upwelling system for the first time. In the absence of representative areas of similar habitat protected from trawling in the southern Benguela region, infaunal and epifaunal assemblages were compared between heavily and lightly trawled areas to assess the impacts of the otter-trawl fishery. Infauna were sampled at four sites, from southern Namibia t...
ABSTRACT The occurrence and diversity of bacteria in selected fish culture ponds from three regions in Ghana, Aduabenba Farms, Agyeman Farms, Aheto Farms, Akuse Kpong Farms, ARDEC Station, Asare Farms, Boadi Farm, Boahen Farms, Boateng Farms, Frimpong Farms, K.K. Farms, Pacific Farms and Sagoe Farms and three open systems, Kpong Head Pond, Volta River and Weija Dam were studied over a period of three years, 1996 - 1999. Bacterial populations from the different fish culture systems studied con...