La région de l’IGAD est particulièrement concernée par les catastrophes naturelles qui sont à l’origine d’importants dégâts humains et économiques. Parallèlement, les pays de l’IGAD figurent parmi les plus pauvres de la planète même si l’on observe de fortes disparités. Le lien entre niveau de richesse, processus de développement et catastrophes naturelles a été peu étudié dans ce contexte. La thèse vise d’abord à développer des méthodes et outils d’analyse pour évaluer les causes et les remédiations possibles des catastrophes naturelles. La recherche se fonde d’abord sur une base de données recensant les impacts des catastrophes naturelles dans cette région. Cette base de données, dénommée BDCanaca, a permis de constater l’existence des disparités spatiotemporelles des dommages des catastrophes naturelles à l’échelle régionale et nationale. La forte vulnérabilité de la région face aux catastrophes naturelles s’explique par l’ampleur des contraintes socio-économiques et politiques notamment les conflits intra ou interétatiques qui ont secoué cette région au cours des dernières décennies. Ensuite, à une échelle locale, la réalisation d’un diagnostic visuel du bâti complété par des enquêtes de terrain a permis d’estimer le niveau de vulnérabilité des ménages installés à proximité des oueds. L’occupation croissante des zones exposées par des populations vulnérables est le principal facteur de production du risque. Afin de limiter les conséquences des catastrophes naturelles, un panel des mesures et des politiques de gestion des risques a été adopté par les États de la région qui figurent parmi les premiers du continent à se doter des structures chargées de la gestion des effets des catastrophes naturelles. Mais ces structures n’ont pas toujours les moyens de mettre en œuvre des politiques efficaces qui gagneraient à intégrer et accompagner les stratégies d’adaptation développées par les populations des régions affectées. / The IGAD region is particularly affected by natural disasters which have caused significant human and economic damages. Despites disparities, IGAD countries are among the poorest in the world. The link between wealth level, development process and natural disasters has been little studied in this context. The main aim of this thesis is to develop methods and tools of analysis to assess the causes and possible remedies of natural disasters. This research is mainly based on a database called BDCanaca which lists natural disasters’ impacts in this region. The data from this database revealed the existence of spatiotemporal disparities in natural disaster damage at regional and national scales as well. The high vulnerability of the region to natural disasters is due to the extent of socio-economic and demographic constraints. It has also shown the heterogeneity of existing sources and the inaccuracy of natural disaster balances. The intrastate or interstate conflicts that have rocked this region over the last decades are factors that explain the enormity of the impacts of natural disasters and therefore its level of vulnerability. The increasing occupation of vulnerable areas by poor populations is the main risk factor. In order to curb the natural disasters’ consequences, a panel of risk management measures and policies has been implemented by the region's states, which are among the first in the continent to procure themselves with managing body to follow up with natural disasters’ effects. But these structures do not always have the means to implement effective policies that would benefit from integrating and supporting the adaptation strategies developed by the populations from affected regions.

A busca pela pacificação da África pode ser considerada como um dos principais desafios encontrados pelos países africanos no imediato pós-independência. Em certa medida, romper com guerras civis e garantir a estabilidade continental foram se tornando algumas das principais preocupações das lideranças africanas. Reflexo disso pode ser encontrado nas várias iniciativas propriamente africanas criadas no continente no período pós-colonial visando à estabilidade e à promoção do desenvolvimento econômico e social do continente. Nesse sentido, o presente trabalho busca compreender a evolução da Arquitetura Africana de Paz e Segurança (AAPS) desde a criação da Organização da Unidade Africana (OUA), em 1963 – primeiro mecanismo africano de segurança –, até os dias atuais, com foco na Autoridade Intergovernamental para o Desenvolvimento (IGAD) na estabilização do Chifre da África. / The search for the pacification of Africa may be considered as one of the main challenges found by African countries in the post-independence immediate period. To some extent, to break off civil wars and guarantee continentall estability increasingly became a major concern of African leaderships. The impact of this can be found in several truly African initiatives created in the post-colonial period, aiming to ensure stabilty and promotion of economic and social development on the continent. In this sense, this work seeks to comprehend the evolution of the African Architecture of Peace and Security (AAPS) since the creation of the Organization of the African Unity in 1963 - first African security mechanism - up to this day, focusing in the Intergovernmental Authority on Development (IGAD) in the estabilisation of the Horn of Africa.

A busca pela pacificação da África pode ser considerada como um dos principais desafios encontrados pelos países africanos no imediato pós-independência. Em certa medida, romper com guerras civis e garantir a estabilidade continental foram se tornando algumas das principais preocupações das lideranças africanas. Reflexo disso pode ser encontrado nas várias iniciativas propriamente africanas criadas no continente no período pós-colonial visando à estabilidade e à promoção do desenvolvimento econômico e social do continente. Nesse sentido, o presente trabalho busca compreender a evolução da Arquitetura Africana de Paz e Segurança (AAPS) desde a criação da Organização da Unidade Africana (OUA), em 1963 – primeiro mecanismo africano de segurança –, até os dias atuais, com foco na Autoridade Intergovernamental para o Desenvolvimento (IGAD) na estabilização do Chifre da África. / The search for the pacification of Africa may be considered as one of the main challenges found by African countries in the post-independence immediate period. To some extent, to break off civil wars and guarantee continentall estability increasingly became a major concern of African leaderships. The impact of this can be found in several truly African initiatives created in the post-colonial period, aiming to ensure stabilty and promotion of economic and social development on the continent. In this sense, this work seeks to comprehend the evolution of the African Architecture of Peace and Security (AAPS) since the creation of the Organization of the African Unity in 1963 - first African security mechanism - up to this day, focusing in the Intergovernmental Authority on Development (IGAD) in the estabilisation of the Horn of Africa.

A busca pela pacificação da África pode ser considerada como um dos principais desafios encontrados pelos países africanos no imediato pós-independência. Em certa medida, romper com guerras civis e garantir a estabilidade continental foram se tornando algumas das principais preocupações das lideranças africanas. Reflexo disso pode ser encontrado nas várias iniciativas propriamente africanas criadas no continente no período pós-colonial visando à estabilidade e à promoção do desenvolvimento econômico e social do continente. Nesse sentido, o presente trabalho busca compreender a evolução da Arquitetura Africana de Paz e Segurança (AAPS) desde a criação da Organização da Unidade Africana (OUA), em 1963 – primeiro mecanismo africano de segurança –, até os dias atuais, com foco na Autoridade Intergovernamental para o Desenvolvimento (IGAD) na estabilização do Chifre da África. / The search for the pacification of Africa may be considered as one of the main challenges found by African countries in the post-independence immediate period. To some extent, to break off civil wars and guarantee continentall estability increasingly became a major concern of African leaderships. The impact of this can be found in several truly African initiatives created in the post-colonial period, aiming to ensure stabilty and promotion of economic and social development on the continent. In this sense, this work seeks to comprehend the evolution of the African Architecture of Peace and Security (AAPS) since the creation of the Organization of the African Unity in 1963 - first African security mechanism - up to this day, focusing in the Intergovernmental Authority on Development (IGAD) in the estabilisation of the Horn of Africa.

A rebours du schéma élaboré dans le cadre du Traité d’Abuja signé le 3 juin 1991 par les Etats membres de L’Organisation de l’unité Africaine (OUA), la divergence actuelle des systèmes régionaux africains constitue une dénaturation de l’approche convenue. Ce texte prévoit en effet dans son article 6, la création des Communautés économiques régionales (CER) comme une modalité de l’intégration continentale. A ce titre, huit CER sont aujourd’hui reconnues par l’Union Africaine : la Communauté Economique des Etats de l’Afrique de l’Ouest (CEDEAO) ; la Communauté Economique des Etats de l’Afrique Centrale (CEEAC) ; la Communauté de l’Afrique de l’Est (CAE) ; la Southern Africa Development Community (SADC); l’Autorité Intergouvernementale pour le Développement (IGAD); le Marché Commun de l’Afrique Australe et Orientale (COMESA); l’Union du Maghreb Arabe (UMA); et la Communauté des Etats Sahélo-Sahariens (CEN-SAD). L’établissement de la Communauté économique africaine instituée par le Traité, reste subordonné à la réussite de ces systèmes communautaires régionaux. Toutefois, la multiplication d’autres organisations communautaires sous-régionales - en plus de celles reconnues - d’une part, et la mise en œuvre de programmes et activités similaires dans le domaine économique d’autre part, tendent à compromettre la réalisation du projet africain. Cette situation fait échec au concept de départ qui établit le principe d’une exclusivité régionale à la faveur de la CER reconnue. A cause de chevauchements des objectifs poursuivis, il s’ensuit entre les organisations régionales, des rapports de rivalité plutôt que de complémentarité, aboutissant à la coexistence des systèmes d’intégration concurrents. Les rapports entre les CER et l’Organisation continentale rendent également visibles les insuffisances liées à la coordination du processus projeté. L’Union Africaine ne disposant pas du tout ou pas suffisamment des moyens juridiques lui permettant une intrusion dans la mise en œuvre des programmes communautaires régionaux, l’application des dispositions du Traité d’Abuja par les CER, ne semble pas homogène. La matérialisation des ambitions affichées par les Etats signataires demeure à ce jour conditionnée par la rationalisation de l’intégration envisagée. Cette étude vise à proposer quelques pistes de solutions en ce sens. / In stark contrast to the vision which emerged from the Treaty of Abuja, ratified by the member states of the Organisation of African Unity on the 3rd of June 1991, the present divergence of regional systems in Africa constitutes a serious distortion of the approach that was agreed upon. Indeed, in Article 6, the treaty sets forth the “strengthening of existing regional economic communities” (RECs) as a means of achieving integration on a continental scale. Along these lines, the African Union now recognizes eight RECs: the Economic Community of West African States (ECOWAS), the Economic Community of Central African States (ECCAS), the East African Community (EAC), the Southern African Development Community (SADC), the Intergovernmental Authority on Development (IGAD), the Common Market for Eastern and Southern Africa (COMESA), the Arab Maghreb Union (AMU), and the Community of Sahel-Saharan States (CEN-SAD). As laid out in the treaty, the establishment of the African Economic Community is entirely dependent upon the success of these regional community systems. At the same time, the increase of other community organisations at the sub-regional level, beyond those officially recognized, on the one hand, and the implementation of similar programmes and activities, on the other hand, tend to endanger the realisation of the African project. This situation flies in the face of the original idea, which was based on the principle of the regional exclusivity of the recognized RECs. As a result of the various overlapping goals that are being pursued by difference organisations, competitive rather than complimentary relations have led to a coexistence of rival systems of integration. The relations between the RECs and the continental organization (the AU) have also made apparent the inadequacy of the coordination procedure that had been envisaged. As the African Union does not have sufficient legal means at its disposal to intervene in the implementation of regional community programmes, the execution of the Treaty of Abuja by the RECs lacks homogeneity. In order to achieve the ambitions declared by those member states who signed the treaty, a rationalisation of the proposed integration is necessary. The present study puts forward several proposals as to how such a rationalisation may be accomplished.

PhD (African Studies) / Centre for African Studies / Abstract In the Horn of Africa, it is often presumed that the Intergovernmental Authority on Development (IGAD) provides an institutional framework for regional integration. IGAD was established in 1986 and its member states include, Djibouti, Ethiopia, Eritrea, Kenya, Somalia, South Sudan, Sudan and Uganda. However, the organisation continues to have many set-backs in its quest for an integrated Horn of Africa. Therefore, this study probed the challenges of regional integration in the Horn of Africa. The study closely examined the regional integration efforts of IGAD and its role and aggregate performance in the sub-region’s search for alternative strategies for sustainable socio- economic development and self-reliance through regional integration. The aim of the study was to investigate mechanisms that might contribute towards the socio-economic growth of IGAD member states. This study adopted a qualitative research approach in the collection of data. The research established the following: That member states of IGAD are not trusting each other and most of them compete over who is more powerful than the other. This competition continues to worsen the already slow integration process. Terrorism in this part of the world continues to hamper progress. In most instances, this phenomenon is tackled harshly, thus leading to more terroristic activities. Participants are of the opinion that this scourge needs a counter ideological stance where people can be educated about

En dépit de sa complexité analytique, la situation sécuritaire de la Corne de l’Afrique peut être soumise aux outils de la Science politique afin de mieux comprendre les interactions entre les différents acteurs. Cette recherche s’efforce d’analyser les ressorts d’une équation sécuritaire qui peut paraître insoluble : le régionalisme est-il aujourd’hui un prérequis à l’émergence d’une paix régionale ? Pour répondre à cette question il est nécessaire de comprendre quels rôles jouent les processus sécuritaires régionaux (régionalisation et régionalisme) dans la construction des États de la Corne de l’Afrique. Cette étude s’efforce d’étudier les interactions entre le régionalisme, fondement de l’architecture de paix et de sécurité continentale, la régionalisation des conflits, qui semble à l’oeuvre dans cette région, et les processus de construction/formation de l’État. Les rapports entre les trois termes de l’équation dépendent du contexte et des interactions entre les différentes entités composant la région (États, acteurs non étatiques qui se dressent contre eux ou négocient avec eux et acteurs extérieurs). Deux types de dynamiques sont mises en évidence au terme de cette étude : l’une endogène, l’autre exogène. Dans la première, nous constatons que les conflits participent à la formation de l’État. Ils sont en grande partie des conflits internes et montrent qu’il existe une crise dans l’État. Ces États dominent le processus de régionalisme qui tente de réguler la conflictualité régionale avec un succès relatif puisque les organisations régionales cherchent à renforcer ou reconstruire l’État selon les critères idéalisés de l’État wébérien vu comme source d’instabilité. Le processus exogène se caractérise par le rôle des conflits régionaux dont l’existence sert de justificatif au développement et au renforcement du régionalisme, perçu comme la réponse la plus appropriée à ces problèmes de conflictualités. Cette conflictualité a pour source l’État car celui-ci est perçu comme faible. Le régionalisme permettrait de renforcer les États et diminuerait leurs velléités de faire la guerre. / In spite of its analytical complexity, the security context in the Horn of Africa may be submitted to the Political Science’ tools in order to better understand the complex interactions between the various actors. The present research thus seeks to analyze the mechanism underlying what appears as an unsolvable security problem: is regionalism a prerequisite for the emergence of a regional peace? In order to answer this question, it is necessary to understand the role of regional security processes (regionalization and regionalism) in the state formation and state building of the Horn of Africa’s states. This study endeavours to explore the interactions between regionalism, which are inherent in the creation of an African peace and security architecture, the regionalization of conflict, which seems at work in this area, and construction/formation state process. The relationship between the three terms of this equation depends on the context and interactions between the various entities that make up the region (states, non-state actors that stand against them or negotiate with the states and external actors). This study thus reveals two kinds of dynamics at play: an endogenous process and an exogenous one. In the first one conflicts are involved in the formation of the state and are largely internal conflicts. It demonstrates that there is a crisis in the state States dominate the regionalism process which tries to regulate regional conflit with relative success because regional organizations seek to strengthen or rebuild the state according to the idealized criteria of the Weberian State seen as a source of instability. The exogenous process is characterized by the role of regional conflicts whose very existence serves to justify the development and the strenghtening of regionalism thus perceived as the most appropriate answer to those security problems. States are the source of conflicts because they are perceived as weak. Regionalism would strengthen states and reduce the inclination of states to make war.

A Imunodeficiência Comum Variável (ICV) e a Deficiência Seletiva de Imunoglobulina A (DIgA) são as imunodeficiências primárias humorais de maior freqüência na população mundial. Ambas as doenças são caracterizadas pela ausência ou redução significativa de imunoglobulinas no soro. Embora diversas anormalidades imunológicas tenham sido associadas a estas doenças, nenhuma hipótese unificadora a respeito das bases moleculares das mesmas foi proposta até o presente momento, sendo que o único defeito comum a todos os pacientes é a falha na diferenciação de células B em plasmócitos e conseqüente secreção de anticorpos. Devido à alta incidência de auto-imunidade e alergia em pacientes com ICV e DIgA, no presente trabalho, visamos analisar por citometria de fluxo a população de linfócitos CD4+ com potencial regulador nesses pacientes, para avaliar se possíveis defeitos quantitativos ou funcionais nesta população reguladora poderiam explicar a alta incidência de doenças auto-imunes ou alérgicas associadas a estas imunodeficiências. / Common Variable Immunodeficiency (CVID) and Selective Immunoglobulin A deficiency (IgAD) are the humoral primary immunodeficiencies with the highest incidence in the population. Both diseases are characterized by the absence or significant reduction of serum immunoglobulins. Although several immunological abnormalities have been associated with these diseases, no unifying hypothesis regarding the molecular basis of CVID and IgAD have been proposed to date, and the only defect common to all patients is the failure in differentiation of B cells into plasma cells and consequent secretion of antibodies. Due to the high incidence of autoimmunity and allergy in patients with CVID and IgAD, in the present work we analyzed by flow cytometry the population of CD4+ lymphocytes with regulatory potential in these patients to assess whether possible quantitative or functional defects in this regulatory population could explain the high incidence of autoimmune diseases or allergic reactions associated with these immunodeficiencies.

A Imunodeficiência Comum Variável (ICV) e a Deficiência Seletiva de Imunoglobulina A (DIgA) são as imunodeficiências primárias humorais de maior freqüência na população mundial. Ambas as doenças são caracterizadas pela ausência ou redução significativa de imunoglobulinas no soro. Embora diversas anormalidades imunológicas tenham sido associadas a estas doenças, nenhuma hipótese unificadora a respeito das bases moleculares das mesmas foi proposta até o presente momento, sendo que o único defeito comum a todos os pacientes é a falha na diferenciação de células B em plasmócitos e conseqüente secreção de anticorpos. Devido à alta incidência de auto-imunidade e alergia em pacientes com ICV e DIgA, no presente trabalho, visamos analisar por citometria de fluxo a população de linfócitos CD4+ com potencial regulador nesses pacientes, para avaliar se possíveis defeitos quantitativos ou funcionais nesta população reguladora poderiam explicar a alta incidência de doenças auto-imunes ou alérgicas associadas a estas imunodeficiências. / Common Variable Immunodeficiency (CVID) and Selective Immunoglobulin A deficiency (IgAD) are the humoral primary immunodeficiencies with the highest incidence in the population. Both diseases are characterized by the absence or significant reduction of serum immunoglobulins. Although several immunological abnormalities have been associated with these diseases, no unifying hypothesis regarding the molecular basis of CVID and IgAD have been proposed to date, and the only defect common to all patients is the failure in differentiation of B cells into plasma cells and consequent secretion of antibodies. Due to the high incidence of autoimmunity and allergy in patients with CVID and IgAD, in the present work we analyzed by flow cytometry the population of CD4+ lymphocytes with regulatory potential in these patients to assess whether possible quantitative or functional defects in this regulatory population could explain the high incidence of autoimmune diseases or allergic reactions associated with these immunodeficiencies.