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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Rôle de la sélection intersexuelle dans l’évolution de la cognition mâle et femelle : approche observationnelle et théorique

Barou-Dagues, Marie 08 1900 (has links)
Choisir un partenaire sexuel est une décision importante pour un animal. Parce que cette décision va considérablement affecter son succès reproducteur, l’individu doit se baser sur un ensemble de traits qui reflètent la qualité du partenaire. Depuis peu, une attention particulière est portée sur l’importance de la cognition dans le contexte de choix de partenaire. En effet, la capacité à percevoir, intégrer, mémoriser et utiliser l’information disponible dans l’environnement permet aux individus de répondre de manière appropriée aux problèmes qu’ils rencontrent et d’ajuster leur comportement en conséquent. Si les femelles retirent un bénéfice à s’apparier avec des mâles capables de répondre aux changements de leur environnement, ces derniers pourraient avoir un accès privilégié à l’appariement lors du choix de partenaire des femelles. Certaines évidences appuient cette idée en démontrant notamment des relations positives entre les capacités cognitives des mâles et leur succès d’appariement et reproducteur et en révélant des préférences sexuelles femelles pour des traits cognitifs mâles. Cependant, ces résultats restent très contrastés, particulièrement chez les animaux non humains où l’importance du choix de partenaire dans l’évolution de la cognition n’est pas encore clairement définie. L’objectif de ma thèse était donc d’explorer le rôle du choix de partenaire dans l’évolution de la cognition mâle et femelle en combinant l’approche observationnelle sur une espèce d’oiseaux monogame et l’approche théorique en utilisant un modèle à base d’agents. Plus précisément, en réalisant des expériences en laboratoire sur le Diamant mandarin (Taeniopygia guttata), j’ai notamment testé si les femelles démontrent une préférence pour des mâles capables d’ajuster leur comportement d’approvisionnement en réponse à un changement environnemental. J’ai ensuite examiné, dépendamment de leurs propres capacités cognitives, si les femelles expriment des préférences pour des mâles performants dans quatre tests psychométriques différents. J’ai finalement exploré les rôles respectifs de la sélection naturelle et intersexuelle en simulant l’évolution de la cognition sous différents scénarios environnementaux. Les résultats de cette thèse ont révélé que les femelles diamants mandarin exprimaient une préférence pour les mâles capables d’ajuster leur comportement d’approvisionnement ainsi que les mâles performants dans certaines tâches cognitives. Cependant, ces préférences n’étaient pas unanimes et dépendaient des propres capacités cognitives des femelles à performer dans ces différentes situations. À l’échelle évolutive, la sélection intersexuelle à travers le choix de partenaire modifiait les patrons d’évolution de la cognition prédits lorsque la sélection naturelle opérait seule. En effet, elle favorisait l’évolution de bonnes capacités cognitives lorsque les contraintes environnementales étaient faibles, mais maintenait de la diversité cognitive lorsque ces contraintes étaient élevées. Dans l’ensemble, ces résultats suggèrent que le choix de partenaire jouerait un rôle important dans l’évolution et le maintien de diversité cognitive au sein des populations. Néanmoins, les conséquences évolutives du choix de partenaire sur les capacités cognitives des individus dépendraient de l’avantage adaptatif à s’apparier avec un mâle plus performant, c’est-à-dire de la capacité cognitive mâle considérée, des caractéristiques des femelles et de l’environnement dans lequel ce choix est fait. / Choosing a mate is an important decision for an animal. Because this decision significantly affects an individual’s reproductive success, it must base its choice according to different traits that reflect the quality of potential mates. Recently, a particular attention has been given to cognitive traits in mate choice context. Indeed, the ability to perceive, integrate, memorize and use the information available in the environment allows individuals to act properly when facing a problem and to adjust their behaviours accordingly. Given that females could benefit from choosing males capable of responding to environmental changes, those with good cognitive abilities should have privileged access to females in mate choice contexts. Some evidence supports this idea by revealing positive relationships between males’ cognitive abilities and their mating and reproductive success as well as female mating preference for male cognitive abilities. However, these results stay contrasted, particularly in non-human animals for which the importance of mate choice in the evolution of cognition is still not clearly defined. The objective of my PhD was to explore the role of mate choice in the evolution of male and female cognition by combining an observational approach using a monogamous bird species and a theoretical approach using an agent-based model. Specifically, by running laboratory experiments on zebra finches (Taeniopygia guttata), I tested whether females demonstrated a mate preference for males able to adjust their foraging behaviour following an environmental change. Then, I investigated whether females, depending on their own cognitive abilities, demonstrated a mate preference for better performers in four different psychometric tests. I finally explored the relative role of natural and sexual selection by simulating the evolution of cognition under different environmental scenarios. The results of this PhD project revealed that zebra finch females preferred males exhibiting greater behavioural plasticity in their foraging tactic use as well as males performing better in several cognitive tasks. However, females’ preference for cognitive abilities was not unanimous but depended on females’ own abilities to perform in these tasks. At the evolutionary scale, intersexual selection through mate choice changed the evolutive patterns observed under natural selection alone. In fact, intersexual selection promoted good cognitive abilities under most favourable environments but maintained cognitive diversity under the harsher ones. Taken together, these results suggest that mate choice plays an important role in the evolution and maintenance of cognitive diversity within populations. Nevertheless, the evolutive consequences of mate choice on individual cognitive abilities should depend on i) the adaptive value of mating with a male with better performance, and thus, on the cognitive ability considered, ii) the female characteristics and iii) the local environment during mate choice.
12

Three Essays on the Role of Corporate Governance in Firms' Spending on R&D and Controlling Earnings-Management Practices: The Role of Independent Directors’ Tenure and Network in Controlling Earnings-Management Practices; The Impact of Board Diversity on the Corporate Propensity to R&D Spending; The Association between Directors’ Multiple-Board Sittings, Tenure, Financial Expertise, and R&D Spending

Asad, Muhammad January 2021 (has links)
This thesis comprises three research essays. The study documents empirical evidence around the research themes by analysing a sample of the UK’s listed non-financial firms from 2005 to 2018. It applied panel data analysis (fixed or random effects) techniques and the potential endogeneity issue is controlled by using the two-step system, GMM. Earnings-management research holds that manipulating a firm's real activities is more damaging to its long-term growth and value than accruals manipulation. Therefore, by building on agency theory and emphasising board monitoring, first essay investigates the role of independent directors’ tenure and connection to several boards in controlling real earnings management (REM). This study finds that independent directors elected to board before appointment of current CEO are negatively associated with the level of REM. Furthermore, this research provides evidence that REM is higher in those firms whose INDs are connected to several boards at a time. Though economically insignificant in most of the models, this research also shows that the association between INDs’ tenure and REM varies with the phases of their tenure. Directors in the early stage of their tenure are observed as being less effective in controlling REM. However, as INDs’ tenure grows, they employ better oversight over management's conduct, thereby reducing REM. Contrary to this, the extended tenure of INDs is associated with higher REM. These results collectively suggest that the board monitoring role protects the stakes of shareholders/stakeholders by constraining REM; when INDs are free from the influence of CEO, they are not over-committed due to their presence on several boards, and they have moderate board tenure which is neither too short nor too long. Furthermore, drawing on collective contributions and group performance perspectives, second essay explores the role of board diversity in the firm’s R&D investment decisions. Additionally, building on a fault-line argument about a team's demographic attributes, the current research decomposes the impact of demographic and cognitive diversity on R&D spending. The research observes a positive relationship between board diversity and the level of R&D spending. Moreover, this research documents that cognitive diversity is positively associated with R&D investment. However, demographic diversity has an insignificant relationship with firms’ spending on R&D projects. Further, this study confirms that demographic diversity negatively moderates the relationship between cognitive diversity and R&D investment. These results suggest that the board's attributes as a group carry the significance to influence the decisions having strategic importance. The findings on the sub-dimensions of board diversity imply that board functional/cognitive diversity is more relevant to corporate decisions and outcomes than is demographic diversity. Based on the monitoring perspective (agency theory) and resource provision view (resource dependency theory), third essay investigates the role of independent directors’ specific attributes in the corporate propensity to R&D investment. The study documents a positive association between INDs’ moderate (median) tenure and the firm’s spending on R&D projects, but early and extended tenure is observed as being insignificant. INDs with a presence on three or fewer boards are observed to promote R&D investment. However, INDs sitting on more than three boards negatively affect the firm’s propensity to invest in R&D initiatives. Financially expert INDs are negatively associated with corporate R&D investments, suggesting that such directors may resist funding these projects beyond optimal risk level because of their expertise. These results suggest that INDs’ monitoring and advising competence improves as they spend time on the firm’s board, but that extended tenure is counterproductive as it impairs INDs’ impartiality. Furthermore, INDs’ capital (resources) accruing from connection to multiple boards is only beneficial for the firm’s strategic decisions if their monitoring role is not compromised because of their over-commitment (busyness). / Mirpur University of Science and Technology (MUST)
13

Filmmaking: a new pedagogical method to explore students' view of nature of science

Kottova, Alena 23 September 2015 (has links)
This dissertation examines the nature, scope, and significance of a new pedagogical approach to teaching of views on nature of science (VNOS) to high school students. Educational approaches based on teaching ‘correct’ VNOS continue to be dominated by the epistemology of logical empiricism and, as I will point out, these approaches are inadequate to address the issues of VNOS. I assert and the findings presented in this dissertation offer evidence that students’ VNOS are dynamic and context-based. In this research I used filmmaking to explore students’ VNOS. High school students, supported by a professional filmmaking crew, completed a short film entitled, The Shadows of Hope; this film explores the use of scientific knowledge in understanding everyday life problems. The filmmaking environment introduced simultaneously a number of contexts in which students’ VNOS were concurrently collected using mixed methods methodology. The results show that contexts sway students’ VNOS and generate a variety of the VNOS for each student. Evidence shows that there is a common, theme-based pattern to individual students’ set of VNOS. The variety of expressed VNOS seemed natural to the students, with no registered discomfort. However, in this study a contrast between students’ VNOS and their ‘school-based’ understanding of science also became apparent. This is evidence that cognitive dissonance is not sufficient to explain the full spectrum of ways in which students learn, deepen knowledge and arrive to conceptual change. I assert that including cognitive contextual expansion in our understanding of conceptual change is essential to provide a framework that allows to integrate cognitive diversity into the theory of learning, reflecting a perhaps more natural way human mind works. The project’s findings offer evidence that students’ VNOS deepened and expanded through filmmaking; students arrived to a more examined and mature VNOS while enjoying the activity of making a film. There is evidence that cooperation with a professional team provided students with a feeling of respect and pride. Filmmaking offers a robust way of learning, based on collaborative work that enlivens a large number of learning-enhancing activities. Additional resources and a Brief Guide For Teachers are added to this text to support teachers in adopting filmmaking as a unique pedagogical method. / Graduate / 0714 / 0900 / 0533 / akottova@uvic.ca

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