Abstract This thesis deals with factors affecting mate choice as well as with genetic variation in male courtship song in Drosophila montana. Males, which produced song with a high carrier frequency, were found to court females, and also to succeed in their courtship more often than the males producing low frequency song. Male mating success correlated with the carrier frequency of his song recorded after, but not before, an "artificial winter", which suggests that a sexually selected male trait is sensitive to environmental factors. A high carrier frequency of male courtship song correlated positively with the survival rate of the male's progeny from egg to adulthood (indirect benefit for the female), but not with the fecundity of his mating partner (no direct benefit for the female). The heritabilities and the amount of additive and residual variation in male courtship song characters were measured in two populations using father-son regression and sib analysis. The songs of the males from one of these populations were analysed for a second time after the cold treatment. Most heritability values were insignificant, largely due to high residual variation. During the cold treatment, the additive variation increased and the residual variation decreased in almost all song traits. Increased variation in sexually selected traits may help the females to exercise selection between the males during the mating season of the flies in the wild in spring. This, and the fact that male song gives the female information about the male's condition/genetic quality suggests that in this species the evolution of female preferences for male song characters could have evolved through condition-dependent viability selection as postulated by "good genes" models. Variation and inbreeding depression/heterosis were studied in traits associated with fly reproduction using inbred D. montana strains. Songs, hydrocarbons and some behavioural traits of the flies varied significantly between strains. The strain of both sexes affected female egg-laying, and the female strain, also, the survival rate of the flies' progeny, in different intra- and interspecific combinations. Heterosis was found in the mating propensity of the flies and in the carrier frequency of the male song. Diallel analysis revealed unidirectional dominance towards higher carrier frequency. This direction is the same as the direction of sexual selection exercised by the females of this species suggesting that sexual selection could be a driving force in evolution of this song trait.

Abstract Habitat selection is a crucial process affecting space use and reproductive success of birds. In this thesis, I investigated spatial and behavioural aspects of nest spacing, brood stage space use, habitat selection and factors affecting reproductive success of breeding common goldeneye (Bucephala clangula) using two large and long-term observational data sets from individually marked females. In the nesting stage, I found that spatial nesting pattern of goldeneye females changed from one year to the next and also between spatial scales. However, increasing aggregation of nesting females decreased nesting success due to increasing rate of nest desertion and nest predation especially at small spatial scale. These results provide evidence of a density-dependent population process in the common goldeneye in terms of association between annual spatial dispersion of nesting females and annual nesting success. In the brood stage, the most important factor affecting habitat selection was the amount of food. However, safe nest sites and food requirements of ducklings were not usually met in the same patch and females with broods adjusted their space-use tactics according to these critical breeding resources. Spatial divergence of these two obligatory resources induced brood movements at various distances shortly after hatching. During movements, broods used different landscape elements such as patches, corridors and matrix in a flexible way without clear fitness consequences in terms of duckling survival. Goldeneye broods suffered heavy losses especially during the early brood stage. Increasing predation risk by northern pike (Esox lucius) decreased survival of young ducklings, but frequent total brood losses suggest that also other factors affected duckling survival. Environmental factors such as temperature or rain were not related to the survival of ducklings.

Abstract For effective management of stream salmonids, it is essential to (i) assess the productive potential of a stream in relation to species-specific habitat requirements, and to (ii) identify the key factors underlying any bottleneck periods during the life cycle of a fish. For this purpose, this PhD-thesis focuses on the mechanisms of habitat selection by juvenile salmonids in boreal streams. Habitat preference curves for depth, water velocity, substrate and instream cover for brown trout (Salmo trutta L.) in river Kuusinkijoki, northeastern Finland, indicated that larger trout preferred deeper stream areas than age-0 trout did. In summer, all size-classes of trout preferred small substrates, whereas in winter, areas with cobble-boulder substrates were preferred. Winter presents a bottleneck period for trout in boreal streams; therefore winter habitat curves should be incorporated into habitat-hydraulic models when estimating habitat suitable for riverine trout in areas with severe winter conditions. The preference curves of age-0 trout were validated by correlating age-0 trout density with habitat availability at multiple sites in two boreal rivers where trout densities were monitored in 1988-1995. Substrate preference curve was effective in predicting trout densities among sites, whereas among-year variation in trout densities was best predicted by depth-related preference curves. The responses of age-0 brown trout and grayling (Thymallus thymallus (L.)) to enhancement structures were investigated in artificial stream flumes. For both species a crucial habitat factor was the availability of flow refuges, especially in winter. In another experiment, age-1 trout dominated over age-0 trout when competing for velocity and overhead cover they both found suitable, emphasizing the role of intraspecific interactions in habitat selection by trout. These results suggest that the provision of a broad diversity of microhabitats should be a major goal in rehabilitation programs for fishery purposes. A new method, combining GIS-assisted (Geographical Information System) approach with geostatistical tools, facilitated the detection of fish distribution patterns in a spatially heterogenous stream habitat. The method will likely prove valuable when determining appropriate sampling scale(s) for future studies of fish habitat selection in relation to benthic prey. Unlike Arctic bullhead (Cottus poecilopus, Heckel), trout did not show any aggregation with their benthic prey according to spatially-referenced data on the distribution of lotic fishes and benthic macroinvertebrates within a stream reach.

Macrophages, phagocytic cells of the immune system involved in host defence, homeostasis and development, are controlled and influenced by a variety of growth factors. In mammals, the colony stimulating factor 1 (CSF1) is a secreted cytokine that controls macrophages survival, proliferation and differentiation. It acts through the CSF1 receptor (CSF1R), a transmembrane receptor tyrosine kinase, expressed mainly in mononuclear phagocytes. Mammalian CSF1R is found exclusively at the surface of the mononuclear phagocytes and their progenitors. CSF1R-/- knockout mice display more severe phenotypes than the CSF1-deficient mice, thus suggesting the existence of another CSF1R ligand. Indeed, recent studies have shown that interleukin 34 (IL34) also binds to and activates CSF1R and regulates monocyte viability in vitro. While the exact role of this protein is yet to be fully elucidated, studies in mammals thus far implied its involvement in embryogenesis and development. CSF1R system is highly conserved within vertebrates and has been identified in variety of mammals. Chicken has been used extensively as a model for vertebrate development and to identify fundamental biological processes. Previous studies by colleagues in the lab demonstrated that the CSF1R system is conserved in the chicken, where it controls the generation of monocytes and tissue macrophages. This thesis provides a thorough evolutionary and structural analysis to fully demonstrate the similarities and differences between avian and mammalian CSF1R systems. The primary objective of this thesis was the comparative functional and structural analyses of the three proteins in birds and mammals, using evolutionary and experimental approaches. Here the presence of CSF1, CSF1R and IL34 genes and protein products is identified in a number of evolutionary diverse birds, indicating that the system is well maintained within the group. Avian genes were cloned and sequenced or otherwise extracted from different databases, and the mammalian sequences were gathered from available online sources. Whilst the gene regulation and the differential expression of the mammalian CSF1R, CSF1 and IL34 are reasonably well understood, they have not been extensively studied in birds. Preliminary comparison between these two groups provided in this thesis suggests a number of similar patterns are involved in regulation of avian CSF1R system. The mammalian CSF1/CSF1R and IL34/CSF1R ligand:receptor peptide interface has been previously resolved and was used to model similar structures in the chicken. The models were then utilised to determine which amino acids are involved in receptor binding in birds. The apparent lack of cross-species reactivity between the chicken CSF1 and zebra finch CSF1R provided a basis for an experimental validation of the in silico binding site predictions. Altogether the structural modelling, evolutionary analysis and experimental confirmation provided sufficient proof for the location of avian CSF1/CSF1R interface. Finally, an extensive bioinformatics analysis has been performed on both the coding DNA and the protein structures of the CSF1R system. The results uniformly showed that IL34 remains under purifying selection in both groups. CSF1 is diverse amongst most mammalian species, while avian CSF1 is only positively selected along particular lineages. This implies the rapid evolution of mammalian CSF1, probably in response to the selection pressure from pathogens. Contrasting situation is found in the CSF1R. Whilst mammalian CSF1R remains positively selected only along particular branches, avian CSF1R presents a number of pervasively positively selected sites, found mostly in the extracellular domains of the receptor. That suggests that in birds it is the receptor, not CSF1, which remains under strong selective pressure. These indicates that birds employ a unique way of competing in the hostpathogen arms race, suggesting the existence of yet unknown pathogen-encoded protein interacting with the avian receptor.

This thesis considers the problem of reconstructing system level behavior of an SoC design from a partially observed signal trace. Solving this problem is a critical activity in post-silicon validation, and currently depends primarily on human creativity and insights. In this thesis, we provide algorithms to automatically infer system level flows from incomplete, ambiguous, and noisy trace data. This thesis also demonstrates the approach on two case studies, a multicore SoC model developed within the within the GEM5 environment, and a cycle accurate register transfer level model of a similar SoC design.

M.A. (Psychology) / The interview appears to be a very popular but nevertheless unreliable and invalid selection instrument. A need therefore exists to improve the selection interview and to place it on a more scientific basis. The purpose of this study can be summarized as the development of: an interview decision-making model an interview reference framework a selection interview interpretation guide Before these topics were discussed, the nature, definition, value, problematics and improvement of the selection interview were examined. Attention was given to the nature, purpose, function, formulation and classifica~ion of interview questions as well as to the interview as a measuring instrument and requirements such as objectivity, appropriateness, adaptability, standardization, reliability and validity. Various decision-making models were examined and discussed, and the decision-making attributes of the decision-maker (the interviewer) were studied. The requirements of the decision making process were discussed and a decision-making model was subsequently developed...

M.Bibl. / The ability to read has particular psychological and educational value for the mentally handicapped pupil. This entails amongst other things the raising of the achievement ceiling of the pupiI because of stimulation and enrichment arising from contact with reading material, as well as achieving of academic goals and the opportunity of becoming and remaining functionally literate. The latter provides the opportunity for dignified adaptation in society. The reading-ability of mentally handicapped pupils can be improved with practice. Mentally handicapped pupils do however have particular characteristics and not just any reading material can be made available to them. Reading material provided for these pupils should be in concordance with their capabilities, needs and interests to ensure that mentally handicapped pupils come into contact with books that they can master and derive benefit from. The formative value of reading and the characteristics, needs and interests of mentally handicapped pupils were identified and were used as a base for the formulation of a variety of criteria that can be used to select reading material for these pupils. A questionnaire was designed based on Fry's readability graph and the identified criteria for selection. This questionnaire can be used for evaluating books to determine whether a book is a high interest low vocabulary book such as is needed for mentally handicapped pupils. This questionnaire provides a useful method for collecting suitable reading material. The questionnaire was used to identify fifty Afrikaans stories with various topics and content, as examples of suitable reading material for mentally handicapped pupils. The conclusion that was drawn is that there are enough high interest low vocabulary stories available in Afrikaans to provide for mentally handicapped pupils in special schools. The selection of such books is time consuming and should be undertaken on a co-operative base by teachers and librarians. The discerning selection of reading material is essential because mentally handicapped pupiIs can be motivated to want to read continuously if they perceive books to be manageable and interesting rather than threat.

The genes of the Major Histocompatibility Complex (MHC) represent the most diverse genomic region in vertebrates, and has become a paradigm both for adaptively important genetic variation and how balancing selection can act to retain diversity in the face of gene flow. Within this thesis I examined how the natural mating system of a population of sea trout (Salmo trutta) located in a stream in N E Scotland, affected levels of genetic diversity at both neutral microsatellite loci and at the MHC. High levels of multiple mating were observed for both males and females whereby females mated with as many as nine males during one spawning event and often spawned at multiple nests and males mated with as many as nine females. Repeat spawning events including the same mate pairs was common, perhaps indicating mate choice. Indeed majority males (those which sired the highest number of offspring within a nest) sired more MHC divergent offspring than expected under random mating i.e. individual offspring's maternally and paternally inherited MHC sequences contained a higher number of polymorphic sites than expected under random mating. This may indicate a mating strategy whereby disassortative MHC mate choice increases offspring diversity. Although, MHC played a significant role in mate selection¸ no selective effect of MHC diversity or genotype was found to influence offspring survival in c.8 month old parr. However, any affect may be masked by the strong family group structure within the offspring population with clustering of highly related individuals. Selective mating resulting in high individual diversity and high diversity across the offspring cohort may act as a bet hedging mechanism maximising the chances that at least some offspring will be genetically equipped to deal with selective pressures in the environment. The findings of this thesis highlight the complexity of individual mating systems and the implications that mating practices such as multiple mating and mate choice can have on offspring genetic diversity.

Teams have become the strategy of choice when the volume of work or task complexity exceeds the capacity of an individual. Therefore the ability for individuals to work in teams is vital in the modern workplace. Consequently a critical lever in facilitating performance of teams is the selection process used to set up teams or bring on board new team members. Teamwork and employee selection have been separately researched. No studies have examined why selection processes have not adapted to include a more formal approach to selection for teams. The information obtained from the literature served as the basis for construction of an a priori model for this study. This model shows the general approach used when selecting individuals through assessing alignment of skills and values, and it was used as a discussion framework during twenty expert interviews. The evaluation of the primary data allowed for validation and extension, for the creation of a more robust a posteriori model. The strategies and practices highlighted by this evaluation have been integrated into a model which can be used for assessing whether organisation specific selection processes are adequate for constructing teams that assist in building competitive advantage. Copyright / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

We study the nature of filter methods for feature selection. In particular, we examine information theoretic approaches to this problem, looking at the literature over the past 20 years. We consider this literature from a different perspective, by viewing feature selection as a process which minimises a loss function. We choose to use the model likelihood as the loss function, and thus we seek to maximise the likelihood. The first contribution of this thesis is to show that the problem of information theoretic filter feature selection can be rephrased as maximising the likelihood of a discriminative model. From this novel result we can unify the literature revealing that many of these selection criteria are approximate maximisers of the joint likelihood. Many of these heuristic criteria were hand-designed to optimise various definitions of feature "relevancy" and "redundancy", but with our probabilistic interpretation we naturally include these concepts, plus the "conditional redundancy", which is a measure of positive interactions between features. This perspective allows us to derive the different criteria from the joint likelihood by making different independence assumptions on the underlying probability distributions. We provide an empirical study which reinforces our theoretical conclusions, whilst revealing implementation considerations due to the varying magnitudes of the relevancy and redundancy terms. We then investigate the benefits our probabilistic perspective provides for the application of these feature selection criteria in new areas. The joint likelihood automatically includes a prior distribution over the selected feature sets and so we investigate how including prior knowledge affects the feature selection process. We can now incorporate domain knowledge into feature selection, allowing the imposition of sparsity on the selected feature set without using heuristic stopping criteria. We investigate the use of priors mainly in the context of Markov Blanket discovery algorithms, in the process showing that a family of algorithms based upon IAMB are iterative maximisers of our joint likelihood with respect to a particular sparsity prior. We thus extend the IAMB family to include a prior for domain knowledge in addition to the sparsity prior. Next we investigate what the choice of likelihood function implies about the resulting filter criterion. We do this by applying our derivation to a cost-weighted likelihood, showing that this likelihood implies a particular cost-sensitive filter criterion. This criterion is based on a weighted branch of information theory and we prove several novel results justifying its use as a feature selection criterion, namely the positivity of the measure, and the chain rule of mutual information. We show that the feature set produced by this cost-sensitive filter criterion can be used to convert a cost-insensitive classifier into a cost-sensitive one by adjusting the features the classifier sees. This can be seen as an analogous process to that of adjusting the data via over or undersampling to create a cost-sensitive classifier, but with the crucial difference that it does not artificially alter the data distribution. Finally we conclude with a summary of the benefits this loss function view of feature selection has provided. This perspective can be used to analyse other feature selection techniques other than those based upon information theory, and new groups of selection criteria can be derived by considering novel loss functions.