This thesis was designed to address three seldom studied aspects of the relationship between herbivores and vegetational diversity. 1. Interactions between vegetational diversity and herbivore mortality due to predation were assessed by experimentally manipulating both the species diversity of plants and the densities of a common generalist predator, the spider Enoplagnatha ovata. 2. The importance of plant size to herbivore densities was examined by quantifying plant size (measured as plant height, width, leaf area and growth rates) and adjusting for it through covariate analysis. 3. Differences in population responses of several species of herbivores to both vegetational diversity and a predator, were compared by concurrently studying four lepidopterans. The main experiment used a two factor design, with two planting treatments and two predator treatments. The planting treatments consisted of plots planted with monocultures of brussels sprouts (Brassica oleraceae) and dicultures of brussels sprouts intercropped with peppermint (Mentha piperita). The natural enemy treatments involved augmentations of E ovata in some plots and untreated controls. Two of the herbivores studied, Plutella xylostella and Pieris rapae are monophagous lepidopterans, specializing on crucifers, while the others, Autographa californica and Mamestra configurata are polyphagous. For two species, P. xylostella and M. configurata responses to augmentations of the spider, E. ovata. were different in monocultures and dicultures. Reduced densities of these two species were found in monoculture plots with added spiders; in dicultures increased densities were found in plots with added spiders. This interaction effect points out that generalist predators can be effective in monocultures. I suggest that the importance of natural enemies in monocultures is often overlooked because only the initial colonization phase is being studied. By augmenting predator populations I was able to simulate densities equivalent to those in more established cropping systems. The increased herbivore densities in dicultures with added spiders might be explained by possible predation by E. ovata on other natural enemies of P. xylostella and M. configurata in dicultures but not in monocultures. Supporting evidence for this interpretation lies in the fact that percent parasitism of P. xylostella by the ichneumonid, Diadegma insulare was lower in plots with added spiders than in control plots. Furthermore, parasitism of P. xylostella by D. insulare increased with host density in diculture plots, but not in monoculture plots. Mamestra configurata was not subject to parasitism in this study, precluding assessment of a similar relationship. No A. californica larvae were found in plots with additional spiders. In contrast, P. rapae larvae were not affected by the experimental treatments. Plant size was a crucial determinant of both herbivore populations and percent parasitism of those herbivores. Most importantly, had plant size not been accounted for, the importance of vegetational diversity to both herbivore densities and percent parasitism would have been overestimated. For example, the incorrect conclusion, that vegetational diversity alone was important in determining the abundance of both of the generalist feeders would have been reached. The greater densities of A. californica in monocultures and M. configurata in dicultures were accounted for by plant size. Without plant size adjustments, percent parasitism of P. xylostella by D. insulare would have been misinterpeted as being greater in monocultures than dicultures. With plant size adjustments, the importance of E. ovata augmentations on lowering percent parasitismwas unmasked. All important interaction effects were discovered only after adjustments for plant size had been made. Despite the low densities of all herbivore species, significant responses to experimental treatments were found in three of the four species studied. Only P.l rapae was unaffected by any of the treatments. However, conclusions based on the feeding ng habits of the herbivores could not be made. The polyphagous feeders were affected by generalist predation as much as the crucifer specialist. Parasitism was found in only two of the species, P. xylostella and A. californica. Of these two species parasitism of the specialist, P. xylostella was affected by both vegetational diversity and generalist predation, whereas parasitism of A. californica was not. My study emphasizes multifaceted interactions between the size and diversity of a primary resource and several trophic levels of consumers. Multifactor models, involving several aspects of a cropping system, are required to uncover the important mechanisms behind variable herbivore responses to vegetational diversity. / Land and Food Systems, Faculty of / Graduate

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Doctorat en sciences sociales, politiques et économiques / info:eu-repo/semantics/nonPublished

Doctorat en Sciences politiques et sociales / info:eu-repo/semantics/nonPublished

This thesis aims at analysing the attitudes of youngsters in Brussels towards sociological minorities. The term “minorities” is used to refer to the main social groups that suffer from subordination and misrecognition by the wider society according to the philosophical theory of recognition: women, lesbians and gay men, and ethnic minorities. Our dataset is composed of a sample of seventy schools in the Brussels Capital Region. In total, three thousand one hundred and twenty one pupils attending in 2007 the last grade of secondary education participated in the study. About half of the sample consists of pupils with a migrant background originating from about 100 different countries. This cultural diversity, reflecting one of the main characteristics of the population of the Brussels Capital Region, is at the centre of the thesis. <p>Because of the hierarchical structure of the sample (pupils aggregated within schools), the culturally diverse population of our sample and the multidimensionality of prejudice, multilevel multivariate linear responses models were performed. In brief, these models allowed us to interpret items regrouped according to their common variation across social (and ethnic) groups and not according to their a priori content similarities. Furthermore, these models allowed us to integrate three different research traditions on prejudice: social psychology on the dimensionality of prejudice, sociology on the impact of socio demographic characteristics on prejudice and school effectiveness research on the role schools may play in reducing pupils’ prejudice. With these models, we could demonstrate the capacity of multilevel techniques to encompass the complexity of prejudice and norms, and to provide an interdisciplinary approach of social processes. <p>Besides the impact of gender and socio economic differences on prejudice, the association between ethnic origin and prejudice was the focus of the analysis at the individual level. Hence, the empirical literature showed that respondents of foreign descent and respondents from the receiving society do not hold similar attitudes towards minorities. This association was investigated in a twofold strategy: after having assessed ethnic differences on the different kinds of prejudice, the explanatory power of possible mediators -such as the experience of group-level institutional discrimination or the bidimensional identification- on this association was tested. The choice of these mediators was influenced by different disciplines of the social sciences. Hence, besides the empirical literature specific to the topic of prejudice, these mediators are derived from theories of political sciences, of sociology of immigration, of social psychology and of cross-cultural psychology. The results showed that these mediators could indeed explain to a large extent ethnic differences on prejudice towards minorities. <p>On the school level, we have shown that the impact schools may have on pupils’ prejudice is a differentiated one. Hence, this impact varies according to both the targets and the dimensions of prejudice. Moreover, besides school institutional characteristics, several contextual characteristics were investigated such as the cultural and social diversity within a school. Our results showed that the impact on prejudice of social and cultural diversity within schools was non-significant. This is, however, most probably related to a masking effect by the specificities of the education landscape in Brussels: differences between schools are huge and homogeneity within schools is important, given that the educational field is highly segregated both in social and in cultural terms. The implications of these results based on an interdisciplinary approach for future research and for policymakers are discussed. <p> / Doctorat en Sciences politiques et sociales / info:eu-repo/semantics/nonPublished

Doctorat en philosophie et lettres / info:eu-repo/semantics/nonPublished

Doctorat en philosophie et lettres / info:eu-repo/semantics/nonPublished

Regulation Brussels I and other procedural legislation of European private international law Diploma thesis is particularly focused on rules regulating jurisdiction according Council Regulation (EC) No 44/2001 on jurisdiction and the recognition and enforcement of judgments in civil and commercial matters, so called Brussels I Regulation. The Brussels I Regulation represents a cornerstone of European judicial cooperation in civil and commercial matters. The main aim of my thesis is to provide comprehensive interpretation of jurisdictional rules in accordance with this regulation. The thesis is systematically divided into nine chapters. The purpose of Chapter One is to introduce a complex issue of European Private International Civil Procedure Law by way of defining the essential terms, subsuming it under the broader framework of private international law and also by describing historical development of this area. Next chapters are entirely concentrated on the Brussels I Regulation. Chapter Two addresses general aspects of this regulation. Those are development and subject matter of the regulation and interpretation of basic terms such as jurisdiction and domicile. Chapter Three deals with scope of application, the understanding of which is fundamental for a correct application. Five subsequent...

European Private International Law - Domicile and Brussels I Regulation Abstract It is undisputable, that the Council Regulation (EC) No 44/2001 on jurisdiction and the recognition and enforcement of judgments in civil and commercial matters, the so-called Brussels I Regulation, constitutes the cornerstone of the European Private International Law. The term domicile, employed as the most important connecting factor for the determination of jurisdiction under the Brussels I Regulation, is the key word thereof. Domicile as such is a very interesting, although complicated, legal concept. This holds true even in the case of domicile for the purposes of Brussels I Regulation. At the European level, the tradition of domicile, being the connecting factor in most cases of the determination of jurisdiction, was established by the Brussels Convention. Nevertheless, it did not provide for a uniform definition. Instead, it referred to the national laws of the then contracting states. By adopting, with an exception, a uniform definition of a legal person's domicile, the Brussels I Regulation has partially deviated from this practice. However, as regards the natural person's domicile, the reference to the national laws of the European Union Member States was upheld. As the understanding of this concept differs from...

This thesis examines literary representations of the city of Brussels in Francophone diasporic writing. Drawing on and exploring the usefulness of memory and trauma studies, postcolonial theory, and spatial studies in a Belgian context, this thesis reads six novels, spanning a contemporary period from 1985 to 2011, by Francophone writers, who themselves or whose parents originate from countries with a history of Belgian and French colonialism: Leïla Houari’s Zeida de nulle part (1985), Pie Tshibanda’s Un fou noir au pays des Blancs (1999), Saber Assal’s A l’ombre des gouttes (2000), José Tshisungu wa Tshisungu’s La Flamande de la gare du Nord (2001), Mina Oualdlhadj’s Ti t’appelles Aїcha, pas Jouzifine (2008) and Patrick François’s La dernière larme du lac Kivu (2011). In doing so, this thesis investigates the multiple ways in which these writers imagine and construct the urban space of Brussels through intersecting transnational trajectories and histories of violence. By analysing how they ‘write’ Brussels, the very architecture and landscape of which are clearly marked by colonialism and labour migration, this thesis offers a critical exploration of how experiences and memories of displacement and exile shape the perception of the urban space in these texts. I argue in particular that these writers either recode certain urban spaces or create new ones in order to construct narratives of marginalisation and belonging. Finally, this thesis aims to join the emerging discussion of ethnic-minority writing in Belgium by providing an understanding of the ambiguous role of Brussels as a postcolonial metropolis and post-war destination for labour migration, while seemingly remaining a peripheral location for Francophone literary production in a cultural sphere that still gravitates towards Paris.