Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal. / L'objectif de cette thèse était de mieux comprendre ce qui contrôle la spécificité parasitaire dans le système hôte-parasite constitué par les poissons de la famille des Sparidae et leurs monogènes (Plathelminthes ectoparasites) spécifiques du genre Lamellodiscus. En d'autres termes, il s'agissait de comprendre les causes amenant une espèce parasite à utiliser une seule ou plusieurs espèces hôtes. On suppose que la spécificité est soumise à des contraintes écologiques et évolutives. L'hypothèse d'une augmentation de la diversité taxonomique avec la spécificité a également été testée. Cela est basé sur l'idée que les espèces généralistes, plus tolérantes à leur environnement, sont supposées être moins sujettes à subir des spéciations après un changement d'hôte, et ainsi être moins diversifiées que les espèces spécialistes. Comme l'histoire évolutive des parasites peut être influencée par celle de leurs hôtes à travers des phénomènes de coévolution, il était nécessaire d'obtenir une phylogénie des hôtes et des parasites. L'étude de la coévolution hôte-parasite dans ce système avait pour but de déterminer si le profil d'association hôte-parasite (et donc la spécificité) est contrôlé par des interactions coévolutives. Des phylogénies ont été élaborées pour les hôtes et les parasites à partir de données moléculaires obtenues par séquençage d'ADN. Cette analyse moléculaire a permis de reconsidérer le statut taxonomique de plusieurs espèces de monogènes : sur la base des sequences obtenues, Lamellodiscus virgula et L. obeliae s'avèrent être une seule espèce (L. virgula), alors que Furnestinia echeneis fait partie du genre Lamellodiscus. Plusieurs méthodes d'étude de la coévolution ont été utilisées dans ce travail. L'une d'elles, ParaFit, a été mise au point pendant la thèse. Toutes les méthodes indiquent que ce système complexe ne semble pratiquement pas être soumis à des phénomènes de cospéciation. Aucun lien entre la diversification taxonoinique et la spécificité n'a pu être mis en évidence chez les Lamellodiscus et la famille qui les contient, les Diplectanidae. Par contre, un tel lien a été mis en évidence au niveau des groupes principaux de parasites. Les déterminants écologiques et phylogénétiques de la spécificité ont ensuite été recherchés à l'aide d'analyses statistiques multivariables. Les variables considérées étaient des caractéristiques des hôtes considérées comme des déterminants écologiques potentiels de la spécificité. La phylogénie des parasites a été prise en compte dans ces analyses à l'aide de méthodes comparatives, comme la méthode des contrastes indépendants. La spécificité apparaît être fortement contrainte par la phylogénie, ce qui suggère l'existence de déterminants génétiquement transmissibles. Les analyses révèlent également que les parasites spécialistes ont tendance à utiliser les hôtes les plus grands. Cela est interprété comme une spécialisation sur une ressource prédictible. / The objective of this thesis was to obtain a better understanding of the factors controlling host specificity in the host-parasite system formed by fish from the family Sparidae and their specific monogeneans parasites from the genus Lamellodiscus (Platyhelminthes). In other words, the goal was to understand the factors determining the number of hosts used by a parasite species. We assumed that specificity is under ecological and evolutionary constraints. The hypothesis of an increase of taxonomic diversity with specificity was also tested. It is based on the idea that generalist species are more tolerant to their environment, and therefore less subject to speciation after a host change event, and are then less diversified than specialist species. Since the evolutionary history of parasites can be influenced by the history of their hosts via coevolutionary interactions, it was necessary to obtain phylogenies for the hosts and parasites. The aim of the study of host-parasite coevolution in this system was to assess if the pattern of host-parasite association (and consequently, specificity) was determined by coevolutionary interactions. Phylogenies were obtained for hosts and parasites from the analysis of DNA sequences. This analysis, carried out at the molecular level, led us to reconsider the taxonomic status of several monogenean species. On the basis of the DNA sequences obtained, Lamellodiscus virgula and L. obeliae appear to form a single species (L. virgula), while Fumestinia echeneis is transferred to the genus Lamellodiscus. Several analytical methods were used to study host-parasite coevolution in this system. Among them, ParaFit was designed during this thesis. All methods agreed that this host-parasite system does not exhibit a general cospeciation pattern. No link between taxonomic diversity and specificity has been found in Lamellodiscus, nor in their family, the Diplectanidae. However, such a link was found when the main groups of parasites were considered. Ecological and phylogenetic determinants of specificity were investigated via multivariate statistical methods. The variables included in the analyses were potential host-related ecological determinants of specificity. The parasite phytogeny was taken into account through comparative methods, including the independent contrasts method. Specificity appears to be strongly constrained by the phylogeny, suggesting the existence of genetically transmitted determinants. The analyses also revealed that Lamellodiscus monogeneans tend to specialize on larger hosts. This is interpreted as a specialization on a predictable resource.

Increasing sophistication of exchange traded fund (ETF) indexation methods required that a comparison be drawn between various methodologies. A performance and risk evaluation of four pre-selected ETF indexation categories were conducted to establish the diversification benefits that each contain. Fundamentally weighted, equally weighted and leveraged ETFs were compared to traditional market capitalisation weighted ETFs on the basis of risk and return. While a literature review presented the theory on ETFs and the various statistical measures used for this study, the main findings were obtained empirically from a sample of South African and American ETFs. Several risk-adjusted performance measures were employed to assess the risk and return of each indexation category. Special emphasis was placed on the Omega ratio due to the unique interpretation of the return series‟ distribution characteristics. The risk of each ETF category was evaluated using the exponentially weighted moving average (EWMA), while the diversification potential was determined by means of a regression analysis based on the single index model. According to the findings, fundamentally weighted ETFs perform the best during an upward moving market when compared by standard risk-adjusted performance measures. However, the Omega ratio analysis revealed the inherent unsystematic risk of alternatively indexed ETFs and ranked market capitalisation weighted ETFs as the best performing category. Equal weighted ETFs delivered consistently poor rankings, while leveraged ETFs exhibited a high level of risk associated with the amplified returns of this category. The diversification measurement concurred with the Omega ratio analysis and highlighted the market capitalisation weighted ETFs to be the most diversified ETFs in the selection. Alternatively indexed ETFs consequently deliver higher absolute returns by incurring greater unsystematic risk, while simultaneously reducing the level of diversification in the fund. / MCom (Risk Management), North-West University, Vaal Triangle Campus, 2014

South Africa’s sluggish economic growth and limited structural transformation are at the core of the country’s high levels of unemployment and poverty. Why some countries are able to grow and others not has been the subject of much academic debate, with recent literature throwing fresh light on the phenomenon by exploring the relationship between growth and a country’s productive structure. It is argued that countries’ heterogeneous productive structures stem from differences in entrenched capabilities and know-how in producing and marketing a very specific set of products. Investigating and comparing what countries actually produce and how this supports economic development yield valuable insights into why countries differ and what their transformation priorities should be. In this study a new analytical approach is adopted to determine the potential growth paths of South Africa’s broader agricultural sector, the so-called agro-complex. Comprising 1 456 primary and processed products as well as production inputs within the food, feed and fibre segments, this broad sector makes an important contribution to economic development through its direct and indirect linkages with other economic sectors as well as its relatively high labour absorption rate. The wide-ranging economic challenges that South Africa faces have clearly gripped the country’s agro-complex. A growing dependency on imports of higher value, processed food has led to deteriorating terms of trade, while limited innovation and diversification in agricultural exports (coupled with a high proportion of re-exports) is seriously constraining the positive impact that the agro-complex could have on the country’s growth rate. In this study, the productive structure of the agro-complex is analysed through the application of the ‘product space’ framework. This methodology investigates the relatedness between products as reflected in the conditional probability of a product being exported in tandem with another product, considering all global trade flows. The proximity value, the measurement of relatedness, between all 1 456 products is used to arrive at the structure and visible evidence of an agricultural product space network. This structure allows potential diversification pathways to be analysed. Research has shown that a country’s diversification process involves moves along pathways to nearby - and thus related – ‘new’ products, which simplifies the redeployment of existing productive capabilities and knowledge. These pathways are identified according to three strategic values, namely structural transformation, market potential and employment creation. The potential for structural transformation is determined by using a product-level measure of complexity, with higher level complexity (i.e. upgrading) going to the core of structural transformation. The potential market demand is determined by examining the prospects for import substitution; producing re-exported products locally; producing new, high-potential export products; and diversifying into new markets with existing export products (with the latter two categories evident in the results of a Decision Support Model (DSM)). Finally, the potential for employment creation is analysed in the light of labour and human capital intensities at product level. The study found that South Africa’s position in the agricultural product space is relatively dispersed. This position is characterised by a proportionally high level of core competencies within the primary agricultural cluster and a limited amount of vertical linkages. Furthermore the analyses showed that, especially the products for which South Africa has developed a significant high level of specialisation such as plums and wines are located in the sparser, less promising, parts of the agricultural product space. Notwithstanding, a total of 60 realistic diversification opportunities are within “reach” from the countries core competencies in the agro-complex. The analysis on structural transformation established that the level of product complexity within the agro-complex is more important for economic development than product diversity per se. It was revealed that South Africa only ranked 69th globally with regards to the complexity of its agro-complex. It was determined that upgrading within the forestry and agro-processing of food clusters hold the most potential for improving this position. The investigation into the potential for diversification driven by market potential revealed fore mostly that the potential for substituting imports as well as re-exports with local production is limited. The market prospects for exporting “new” products and expanding the export destinations of existing products within the agro-complex is much more favourable. It was estimated that most employment creation could be derived from diversification within the primary agricultural cluster although its number of opportunities are limited. Diversification within both the primary agricultural and agro-processing of food clusters was found the have to most favourable prospects for developing the level of human capital within the agro-complex. Based on all three strategic values, the most promising diversification opportunities are located within the forestry cluster. The range of realistic opportunities within the five clusters of the agro-complex form the core for developing product-level diversification strategies. This will ultimately strengthen the position of the agro-complex and boost South Africa’s growth path for the next decade. Hence, the main contribution of this study includes the determination of the structure of South Africa’s agro-complex from a product perspective and its implications for potential growth and development. / PhD (International Trade), North-West University, Potchefstroom Campus, 2014

The South African government recognises the need for export growth to contribute towards economic growth and articulates this in different national policy documents. It is evident that the Western Cape Province also recognises the need for export growth, as the province is facing various economic and socio-economic challenges. Therefore, aligning policies to focus on export promotion which supports the labour intensive sectors within the province by uplifting employment and eradicate poverty. The aim of this study is to determine specifically export market diversification opportunities for the Western Cape Province. The main objective is to determine the Western Cape’s world-wide market diversification opportunities with the highest export potential. The literature underlines the importance of export growth and the benefits of export diversification. It can also be concluded that countries operating in the extensive margin are more likely to generate high economic growth and development opportunities. By implementing export diversification strategies, higher employment levels and output growth can be achieved on a provincial and national level. A three-step methodological process to determine the export market diversification opportunities for the Western Cape Province is used. Firstly, the products in which the Western Cape Province has a revealed export specialisation are determined by using the revealed trade advantage (RTA); secondly, the geographical concentration of the Western Cape’s exports of these products is determined by means of the Herfindahl Hirschman Index (HHI); and lastly, the export market opportunities for the Western Cape Province’s export-orientated products that are geographically concentrated are determined by using the decision support model (DSM). The results of the study identified 188 geographically concentrated export products for the Western Cape and 2 866 realistic product-country level export diversification opportunities. It is recommended that the Department of Trade and Industry (DTI) and the Western Cape trade promotion organisation, WESGRO, in collaboration with the relevant export councils and industry associations, use the results of this study to focus their export promotion and diversification strategies on the identified product-country combinations. / MCom, North-West University, Potchefstroom Campus, 2015

South Africa’s sluggish economic growth and limited structural transformation are at the core of the country’s high levels of unemployment and poverty. Why some countries are able to grow and others not has been the subject of much academic debate, with recent literature throwing fresh light on the phenomenon by exploring the relationship between growth and a country’s productive structure. It is argued that countries’ heterogeneous productive structures stem from differences in entrenched capabilities and know-how in producing and marketing a very specific set of products. Investigating and comparing what countries actually produce and how this supports economic development yield valuable insights into why countries differ and what their transformation priorities should be. In this study a new analytical approach is adopted to determine the potential growth paths of South Africa’s broader agricultural sector, the so-called agro-complex. Comprising 1 456 primary and processed products as well as production inputs within the food, feed and fibre segments, this broad sector makes an important contribution to economic development through its direct and indirect linkages with other economic sectors as well as its relatively high labour absorption rate. The wide-ranging economic challenges that South Africa faces have clearly gripped the country’s agro-complex. A growing dependency on imports of higher value, processed food has led to deteriorating terms of trade, while limited innovation and diversification in agricultural exports (coupled with a high proportion of re-exports) is seriously constraining the positive impact that the agro-complex could have on the country’s growth rate. In this study, the productive structure of the agro-complex is analysed through the application of the ‘product space’ framework. This methodology investigates the relatedness between products as reflected in the conditional probability of a product being exported in tandem with another product, considering all global trade flows. The proximity value, the measurement of relatedness, between all 1 456 products is used to arrive at the structure and visible evidence of an agricultural product space network. This structure allows potential diversification pathways to be analysed. Research has shown that a country’s diversification process involves moves along pathways to nearby - and thus related – ‘new’ products, which simplifies the redeployment of existing productive capabilities and knowledge. These pathways are identified according to three strategic values, namely structural transformation, market potential and employment creation. The potential for structural transformation is determined by using a product-level measure of complexity, with higher level complexity (i.e. upgrading) going to the core of structural transformation. The potential market demand is determined by examining the prospects for import substitution; producing re-exported products locally; producing new, high-potential export products; and diversifying into new markets with existing export products (with the latter two categories evident in the results of a Decision Support Model (DSM)). Finally, the potential for employment creation is analysed in the light of labour and human capital intensities at product level. The study found that South Africa’s position in the agricultural product space is relatively dispersed. This position is characterised by a proportionally high level of core competencies within the primary agricultural cluster and a limited amount of vertical linkages. Furthermore the analyses showed that, especially the products for which South Africa has developed a significant high level of specialisation such as plums and wines are located in the sparser, less promising, parts of the agricultural product space. Notwithstanding, a total of 60 realistic diversification opportunities are within “reach” from the countries core competencies in the agro-complex. The analysis on structural transformation established that the level of product complexity within the agro-complex is more important for economic development than product diversity per se. It was revealed that South Africa only ranked 69th globally with regards to the complexity of its agro-complex. It was determined that upgrading within the forestry and agro-processing of food clusters hold the most potential for improving this position. The investigation into the potential for diversification driven by market potential revealed fore mostly that the potential for substituting imports as well as re-exports with local production is limited. The market prospects for exporting “new” products and expanding the export destinations of existing products within the agro-complex is much more favourable. It was estimated that most employment creation could be derived from diversification within the primary agricultural cluster although its number of opportunities are limited. Diversification within both the primary agricultural and agro-processing of food clusters was found the have to most favourable prospects for developing the level of human capital within the agro-complex. Based on all three strategic values, the most promising diversification opportunities are located within the forestry cluster. The range of realistic opportunities within the five clusters of the agro-complex form the core for developing product-level diversification strategies. This will ultimately strengthen the position of the agro-complex and boost South Africa’s growth path for the next decade. Hence, the main contribution of this study includes the determination of the structure of South Africa’s agro-complex from a product perspective and its implications for potential growth and development. / PhD (International Trade), North-West University, Potchefstroom Campus, 2014

The South African government recognises the need for export growth to contribute towards economic growth and articulates this in different national policy documents. It is evident that the Western Cape Province also recognises the need for export growth, as the province is facing various economic and socio-economic challenges. Therefore, aligning policies to focus on export promotion which supports the labour intensive sectors within the province by uplifting employment and eradicate poverty. The aim of this study is to determine specifically export market diversification opportunities for the Western Cape Province. The main objective is to determine the Western Cape’s world-wide market diversification opportunities with the highest export potential. The literature underlines the importance of export growth and the benefits of export diversification. It can also be concluded that countries operating in the extensive margin are more likely to generate high economic growth and development opportunities. By implementing export diversification strategies, higher employment levels and output growth can be achieved on a provincial and national level. A three-step methodological process to determine the export market diversification opportunities for the Western Cape Province is used. Firstly, the products in which the Western Cape Province has a revealed export specialisation are determined by using the revealed trade advantage (RTA); secondly, the geographical concentration of the Western Cape’s exports of these products is determined by means of the Herfindahl Hirschman Index (HHI); and lastly, the export market opportunities for the Western Cape Province’s export-orientated products that are geographically concentrated are determined by using the decision support model (DSM). The results of the study identified 188 geographically concentrated export products for the Western Cape and 2 866 realistic product-country level export diversification opportunities. It is recommended that the Department of Trade and Industry (DTI) and the Western Cape trade promotion organisation, WESGRO, in collaboration with the relevant export councils and industry associations, use the results of this study to focus their export promotion and diversification strategies on the identified product-country combinations. / MCom, North-West University, Potchefstroom Campus, 2015

Increasing sophistication of exchange traded fund (ETF) indexation methods required that a comparison be drawn between various methodologies. A performance and risk evaluation of four pre-selected ETF indexation categories were conducted to establish the diversification benefits that each contain. Fundamentally weighted, equally weighted and leveraged ETFs were compared to traditional market capitalisation weighted ETFs on the basis of risk and return. While a literature review presented the theory on ETFs and the various statistical measures used for this study, the main findings were obtained empirically from a sample of South African and American ETFs. Several risk-adjusted performance measures were employed to assess the risk and return of each indexation category. Special emphasis was placed on the Omega ratio due to the unique interpretation of the return series‟ distribution characteristics. The risk of each ETF category was evaluated using the exponentially weighted moving average (EWMA), while the diversification potential was determined by means of a regression analysis based on the single index model. According to the findings, fundamentally weighted ETFs perform the best during an upward moving market when compared by standard risk-adjusted performance measures. However, the Omega ratio analysis revealed the inherent unsystematic risk of alternatively indexed ETFs and ranked market capitalisation weighted ETFs as the best performing category. Equal weighted ETFs delivered consistently poor rankings, while leveraged ETFs exhibited a high level of risk associated with the amplified returns of this category. The diversification measurement concurred with the Omega ratio analysis and highlighted the market capitalisation weighted ETFs to be the most diversified ETFs in the selection. Alternatively indexed ETFs consequently deliver higher absolute returns by incurring greater unsystematic risk, while simultaneously reducing the level of diversification in the fund. / MCom (Risk Management), North-West University, Vaal Triangle Campus, 2014

Is home biasness common among modern investors? To which extent do Swedish investors diversify their investments on an international level? Does home biasness negatively affect the investors performance? To answer these questions, correlation tests of various international indices ranging over four different time periods are conducted, in order to see if correlation between markets are stronger today than before, as stronger correlation would render diversification less useful. To enhance the study, the holdings of the top ten Swedish funds, measured in fund capital according to Morningstar, is reviewed, based on data collected per 2014-12-31 from the Swedish Financial Supervisory Agency (FI). This gives an overview of how the funds diversify their investments internationally, these funds will in turn represent the average Swedish investor in the thesis. By constructing a bullet curve from a set of international indices, the author will analyse to which grade international diversification is useful. The results are that international diversification isn’t as beneficial as theory suggests it is. The reason for it may be due to stronger correlation between international markets in the past 15 years. Most of the Swedish funds tends to be rather home biased in their investments, as about a quarter of the holdings usually are placed in Swedish assets, and in accordance with the results of the indices development, the more home biased they are to Sweden, the better they tend to perform. / Hur vanligt är egentligen home biasness hos den moderna investeraren? Till vilken grad diversifierar egentligen den vanliga Svenska investeraren sina tillgångar internationellt? Påverkar en eventuellt inhemskt investeringsfilosofi investeraren negativt? Korrelationstester för olika världsindex kommer utföras, så att en överskådade blick kan fås över hur världsmarknader rör sig allt mer symmetriskt, då starkare symmetri mellan marknader minskar nyttan av internationell diversifiering. Data om innehav från Sveriges topp tio fonder, sett till fondförmögenhet utifrån Morningstar, har samlats från finansinspektionen per 2014-12-31. Dessa fonder ska representera den typiske Svenska investeraren och dess diversifieringsvanor. Genom att ha samlat data från ett flertal internationella index har effektiv front samt en fiktiv kombination av index skapats för att få fram huruvida avkastning i relation till risk ökar genom internationell diversifiering. Denna kombination av index jämförs sedan mot utveckling av en handfull internationellt samlade index för att se om diversifiering förbättrar avkastningen i relation till risk. Resultatet säger att det index som är mest diversifierade inte är så gynnsamt som teorin påstår. Anledningen till detta kan bero på den ökade korrelationen bland aktiemarknader idag jämfört med för 15 år sedan. De flesta Svenska fonderna har en större andel av sitt innehav i Svenska värdepapper och överlag, förutom diverse undantag, så har det gynnat dessa fonder i avkastning sett till risk.

Digital divide research has recently begun to address the functional gaps between Internet-connected technologies, specifically mobile and wired devices. This study uses nationally representative survey data from the Pew Internet and American Life Project to address this area of research and explores how smartphone-dependence compared to multi-modal access impacts Internet use among key demographic groups including race, sex, age, income, and education. This study also explores how demographic characteristics and smartphone use interact to affect reliance on smartphones and perceptions of the utility of mobile devices. Results show that race, sex, age, income, and education, exhibit different rates of smartphone-dependence, and also perform different online activities with their smartphones. Minorities and younger users are more likely to be smartphone-dependent and multi-modal users suggesting that these demographic groups are adopting mobile Internet technologies faster than Whites and older individuals. Minorities also use smartphones for more news and information activities than Whites, which contradicts traditional usage gap predictions.

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