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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.
101

A arquitetura de segurança na África Austral (SADC) : surgimento e desenvolvimento de uma comunidade de segurança

Mbebe, Fernando Rodrigo January 2010 (has links)
Este trabalho descreve e analisa a formação e desenvolvimento de uma comunidade de segurança na África Austral, desde a formação do grupo de Países da Linha da Frente até ao surgimento do Órgão da SADC para a Cooperação nas áreas de Política, Defesa e Segurança. Na região da África Austral, a África do Sul foi considerada, pela maioria dos países vizinhos (Países da Linha da Frente), uma nação inimiga durante o período em que vigorou a política de segregação racial - o apartheid. Assim, esses países tiveram que formar uma frente comum para lutar contra o regime do apartheid. Entretanto, com o fim da Guerra Fria teve lugar o surgimento de uma «nova» ordem internacional. Este fenômeno levou à pacificação da África Austral que passou a cooperar em vários domínios, em particular na segurança. Em 2001, após longas negociações, os Estados membros da SADC assinaram o Protocolo que instituiu o Órgão da Segurança da SADC responsável por todos os assuntos de Defesa e Segurança. Este órgão teve a difícil missão de gerir todos os assuntos ligados a segurança regional na SADC. Contudo, as suas intervenções nos processos de resolução e gestão de conflitos no Lesotho, na RDC, no Zimbábue e no Madagáscar têm se revelado pouco eficazes. / This paper describes and analyzes the formation and development of a security community in Southern Africa since the formation of the countries of the Front Line to the emergence of the SADC Organ for Cooperation on Politics, Defense and Security. In the region of Southern Africa, South Africa was regarded by most neighboring countries (Front Lines States), an enemy nation during the period which ran the policy of racial segregation – apartheid. Thus, these countries had to form a common front to fight against the apartheid regime. However, with the Cold War saw the emergence of a "new" international order. This phenomenon has led to peace in Southern Africa has been cooperating in various fields, particularly in security. In 2001, after lengthy negotiations, the SADC member states signed the Protocol establishing the Organ of SADC Security responsible for all matters of Defense and Security. This body had the difficult task of handling all issues related to regional security in SADC. However, its interventions in the process of resolution and conflict management in Lesotho, the DRC, Zimbabwe and Madagáscar has proved ineffective.
102

Surveillance acoustique des baleines bleues Antarctique dans l’océan Indien austral : traitement, analyse et interprétation / Acoustic monitoring of Antarctic blue whales in the Southern Indian Ocean : data processing, analysis and interpretation

Leroy, Emmanuelle 25 September 2017 (has links)
La baleine bleue Antarctique, Balaenoptera musculus intermedia, est en danger critique d’extinction depuis la chasse baleinière intensive du 20e siècle. L’état de ses populations et leur écologie restent encore mal connus. En raison de l’inefficacité des observations visuelles, la surveillance par acoustique passive est privilégiée pour étudier cette espèce vocalement très active. Cette thèse porte sur l’analyse de 7 ans de surveillance acoustique passive dans l’océan Indien austral, région d’habitat et de migration particulièrement importante pour la baleine bleue Antarctique. Déployé depuis 2010 sur une aire de près de 9 000 000 km2, le réseau d’hydrophones OHASISBIO fournit une base de données acoustiques multi-site et pluri-annuelle. L’application d’un algorithme de détection automatique des vocalisations de baleines bleues Antarctique, préalablement testé et validé, a permis d’établir les patrons géographiques et saisonniers de présence de l’espèce au sein du réseau. L’analyse systématique de ces vocalisations a également permis de caractériser des variations intra- et inter-annuelles de leur fréquence, affectée par une décroissance long-terme et des modulations saisonnières. L’analyse préliminaire de signatures vocales d’autres espèces présentes dans le réseau - rorquals communs et trois populations de baleines bleues pygmées – a révélé des variations de fréquence similaires de leur vocalisation et permis d’esquisser leurs patrons géographiques et saisonniers. Enfin, deux vocalisations, jusqu’alors non décrites, aux caractéristiques semblables à celles de baleines bleues, ont été identifiées et caractérisées. / The Antarctic blue whale, Balaenoptera musculus intermedia, is currently critically endangered since the commercial whaling in the 20th century. The population recovery of this species, as well as its ecology, are still poorly known. Due to the ineffectiveness of visual observations, passive acoustics is a preferred method to monitor this highly vocal species. This dissertation presents an analysis of 7 years of passive acoustic monitoring in the southern Indian Ocean, known as a particularly important area of habitat and migration for the Antarctic blue whale. Deployed since 2010 over an area of about 9,000,000 km2, the OHASISBIO hydrophone network provides a multi-site and multi-year acoustic database. An algorithm for the automated detection of Antarctic blue whale calls, first tested and validated, has been applied to characterize the seasonal and geographic patterns of the species presence in the study area. The systematic analysis of these vocalizations also allowed to characterize intra- and inter-annual variations of their frequency, with a long-term decline and seasonal variations. A preliminary analysis of other vocal signatures recorded by the network, from 3 populations of pygmy blue whales and fin whales, highlighted similar variations of their frequencies and outlined their geographic and seasonal patterns of presence in the area. Finally, two previously undescribed vocalizations, with characteristics close to that of blue whale calls, were identified and characterized.
103

Análise decadal do fluxo de CO2 entre o oceano e a atmostera na Passagem de Drake, Oceano Austral / Decadal analysis of the CO2 sea-air flux in the Drake Passage, Southern Ocean

Franco Nadal Junqueira Villela 25 August 2011 (has links)
VILLELA, FRANCO N. J. Análise decadal do fluxo de CO2 entre o oceano e a atmosfera na passagem de Drake, Oceano Austral. 2011. 148 f. Dissertação (mestrado) Programa de Pós-Graduação em Ciência Ambiental (PROCAM), Universidade de São Paulo, São Paulo, 2011. Para a área delimitada pelos paralelos 60ºS e 62,5ºS e pelos meridianos 60ºW e 65ºW, localizada no sul da Passagem de Drake, no Oceano Austral, próximo à Península Antártica, foram calculadas as distribuições médias de 2000 a 2009, sazonais e anual, do fluxo de CO2 na interface oceano-atmosfera e de suas variáveis associadas: a pressão parcial de CO2 na superfície marinha (PCO2sw), a pressão parcial de CO2 na atmosfera (PCO2ar), a diferença da pressão parcial de CO2 entre o oceano e a atmosfera (PCO2) e a taxa de transferência gasosa (TR), que é produto do coeficiente solubilidade do CO2 na água do mar pela velocidade de transferência gasosa. A parametrização utilizada no cálculo dos fluxos foi a de Takahashi et al. (2009) com TR dependente da velocidade do vento ao quadrado multiplicada por um fator de escala 0,26. A área de estudo tem cerca de 75 mil km2 e foi dividida em uma grade espacial de 0,5º x 0,5º, resultando em 50 quadrículas. Foram utilizados mais de 46 mil medições de PCO2sw, que na média espacial variou de 362,7 ±11,2 a 371,9 ±17,5 µatm, no verão e primavera respectivamente. A PCO2 variou de -0,4 a 5,7 µatm no outono e primavera, respectivamente. A TR variou de 0,065 ±0,04 a 0,088 ±0,002 gC.mês-1.m-2.µatm-1, no verão e inverno, respectivamente. O fluxo líquido, se tomando a concentração de gelo como negligenciável, variou de -0,039 ±0,865 a 0,456 ±1,221 gC.m-2.mês-1, no outono e inverno, respectivamente. O fluxo total anual de carbono, estimado através da média espacial por quadrícula, foi de 95 GgC.ano-1. Dessa maneira, na estimativa anual, a superfície do mar se comporta como fonte de CO2 para a atmosfera, principalmente devido à região da plataforma continental com PCO2sw consideravelmente maior que o da atmosfera. Sazonalmente sugere-se que no verão a maior disponibilidade de radiação solar, a temperatura da superfície do mar (TSM) mais elevada e os ventos mais fracos favorecem a produção de biomassa fitoplanctônica, fazendo com que a bomba biológica seja o processo dominante na diminuição da PCO2sw e na absorção de CO2 atmosférico pela superfície marinha. Já no inverno, os ventos se intensificam e, associados com o forte resfriamento da TSM, promovem a mistura com águas profundas ricas em carbono inorgânico dissolvido, levando a superfície marinha a um estado de supersaturação de CO2 em relação à atmosfera. Ventos circumpolares de oeste mais intensos e deslocados para sul tem sido apontados como a causa do aumento da PCO2sw em igual ou maior taxa do que ocorre na atmosfera. Na área de estudo foi levantada uma tendência média da intensidade do vento de 0,23 ±0,03 m.s-1.década-1 e um aumento na freqüência da componente zonal de oeste (positiva) de 1,47 ± 1,13 % .década-1. Sugere-se que estas tendências estejam relacionadas com o Modo Anular Austral (SAM). Entretanto, a tendência decadal estimada para a PCO2sw foi menor que para a atmosfera, apesar de ambas indicarem tendência de aumento. Acredita-se que a grande variabilidade e distribuição esparsa de dados tenham mascarado a magnitude da estimativa da tendência de PCO2sw. / VILLELA, FRANCO N. J. Decadal analysis of the CO2 sea-air flux in the Drake Passage, Southern Ocean 2011. 148 f. Dissertação (mestrado) Programa de Pós-Graduação em Ciência Ambiental (PROCAM), Universidade de São Paulo, São Paulo, 2011. For the area bounded by parallels 60°S and 62.5°S and meridians 60°W and 65°W, located in the southern Drake Passage in the Southern Ocean, near the Antarctic Peninsula, mean seasonal and annual distributions of CO2 flux at the ocean-atmosphere interface, from 2000 to 2009, have been computed, as well as their associated variables: the CO2 partial pressure at sea surface (PCO2sw), the CO2 partial pressure in atmosphere (PCO2ar), the CO2 pressure difference between ocean and atmosphere (PCO2), and the gas transfer rate (TR), which is the product of the CO2 solubility coefficient in sea water by the gas transfer velocity. The parameterization used to calculate fluxes was that of Takahashi et al. (2009) with TR depending on the squared wind speed multiplied by a scale factor 0.26. The study area has about 75,000 km2 and was divided into a grid of 0.5° x 0.5°, resulting in 50 area boxes. Over 46,000 PCO2sw measurements were used, which in the spatial mean varied from 362.7±11.2 to 371.9±17.5 µatm, in summer and spring, respectively. The PCO2 varied from 0.4 to 5.7 µatm in autumn and spring, respectively. TR varied from 0.065±0.04 to 0,088±0.002 gC.month-1.m-2.µatm-1, in summer and winter, respectively. The net flux, taking ice concentration as negligible, varied from 0.039±0.865 to 0.456±1.221 gC.month-1.m-2, in autumn and winter, respectively. The total annual carbon flux, estimated through the spatial mean per square, was 95 GgC.y-1. Thus, in the annual estimate the region acts as a source to the atmosphere, mainly due to the continental shelf having PCO2sw considerably greater than that of the atmosphere. Seasonally, it is suggested that in summer the greater availability of solar radiation, warmer sea surface temperature (SST), and weaker winds favor the production of phytoplanktonic mass, making the biological pump the dominating process in lowering the PCO2sw and the absorption of atmospheric CO2 by the sea surface. On the other hand, in winter winds intensify and, in association with the strong cooling of the SST, promote mixing with deep waters rich in dissolved inorganic carbon, leading the sea surface to a state of supersaturation in CO2 relative to the atmosphere. Stronger circumpolar west winds and displaced to the south have been pointed as the cause for the increase of PCO2sw at a rate equal to or greater than that occurring in the atmosphere. In the study area it has been detected a mean trend of wind intensity 0.23±0.03 m.s-1.decade-1 and an increase in the western zonal component of 1.47±1.3%.decade-1. It is suggested that these trends are related to the Southern Annular Mode (SAM). However, the decadal trend estimated for the PCO2sw was smaller than for the atmosphere, in spite of both indicating increasing tendencies. It is believed that the great variability and scatter distribution of the data have masked the magnitude of the PCO2SW trend estimate.
104

[pt] CARTOGRAFIAS CINEMATOGRÁFICAS: JOHANNESBURGO, MAPUTO E HARARE EM FILMES CONTEMPORÂNEOS PRODUZIDOS NA ÁFRICA AUSTRAL / [en] CINEMATOGRAPHIC CARTOGRAPHIES: JOHANNESBURG, MAPUTO AND HARARE IN CONTEMPORARY FILMS PRODUCED IN SOUTHERN AFRICA

MARCELO RODRIGUES ESTEVES 24 June 2021 (has links)
[pt] Partindo da indagação o que filmam os diretores africanos contemporâneos quando, hoje, apontam suas câmeras para as cidades, esta tese empreende uma viagem investigativa por Johannesburgo, Maputo e Harare através dos filmes de diretores africanos em atividade na África Austral. Os cinemas africanos contemporâneos realizados em países como África do Sul, Moçambique e Zimbabwe lidam, ainda hoje, em maior ou menor grau, com os reflexos de modos de produção que tiveram origem no período de dominação colonial. Se, na contemporaneidade, a África do Sul logrou organizar uma estável indústria de cinema no sul do continente africano, países como Moçambique e Zimbabwe ainda sofrem com os reflexos de uma descolonização tardia dos modos de produção cinematográfica. Com a queda do apartheid na África do Sul (1994) e as independências de Moçambique (1975) e Zimbabwe (1980), as cidades, territórios severamente marcados pela segregação perpetrada pelo colonizador, passam a atrair a atenção de cineastas locais, ao se transformarem no palco de acirrados debates acerca da segregação racial e espacial, do direito à terra e à moradia, da mobilidade, da relação campo-cidade, do embate entre tradição e modernidade. As cidades africanas, até certo momento tidas como projetos interrompidos e inacabados do pesadelo colonial, passaram a ser consideradas, em toda a sua complexidade, como a epítome da própria modernidade africana. As imagens dessas cidades modernas, complexas e desiguais, que emergem do cinema contemporâneo local, rasuram ou perturbam o regime dominante de representação do continente africano propagado pelo cinema e pela mídia ocidentais, problematizam visões que prevaleceram nos contextos de luta anticolonial e conquista da independência e contribuem para a renovação do repertório de imagens da África arquivadas pelo Ocidente. Os filmes analisados nesta tese ajudam a criar cartografias outras das cidades africanas levadas às telas. Tais cidades cinemáticas – ao editar, seccionar, justapor, aproximar e eliminar espaços – produzem percepções múltiplas e, às vezes, inesperadas. / [en] Starting from the question what do contemporary African directors film, today, when they point their cameras towards the cities, this thesis undertakes an investigative journey through Johannesburg, Maputo and Harare in the films of African directors currently active in Southern Africa. Contemporary African cinemas produced in countries such as South Africa, Mozambique and Zimbabwe are still dealing, to a greater or lesser extent, with modes of production that originated in the period of colonial domination. If, in contemporary times, South Africa has managed to create a stable film industry in the south of the African continent, countries such as Mozambique and Zimbabwe still suffer from the reflexes of the late decolonization of their modes of film production. With the fall of apartheid in South Africa (1994) and the independence of Mozambique (1975) and Zimbabwe (1980), these cities, territories which are severely marked by the segregation perpetrated by the colonizer, start to attract the attention of local filmmakers, as they become the stage of heated debates regarding racial and spatial segregation, the right to land and to housing, mobility, the relation between countryside and urban life, the clash between tradition and modernity. African cities, for a long time regarded as unfinished and interrupted projects of the colonial nightmare, started to be perceived in all of their complexity, as the epitome of African modern itself. The images of these modern, complex and unequal cities, which emerge from local contemporary cinema, disturb the dominant system of representation of the African continent, propagated by Western cinema and media. They also problematize visions that prevailed in the contexts of anti-colonial struggle and conquest of independence and they contribute to the renewal of the repertoire of African images archived by the West. The films analyzed in this thesis help to create alternate cartographies for the African cities brought to the screen. Such cinematic cities – by means of editing, sectioning, juxtaposing, approximating and eliminating spaces – create perceptions that are multiple and, at times, unexpected.
105

Comportement alimentaire des éléphants de mer dans un océan à très fine échelle / Southern Elephant Seal foraging behaviour in a very fine scale ocean

Jaud, Thomas 19 November 2015 (has links)
La dynamique océanique, notamment dans les régions Australes, se caractérise par d'importantes fluctuations induites par les processus à mésoéchelle (tourbillons, 100-200km) et à sous-mésoéchelle (filaments, <50km). Ces processus sont connus pour stimuler fortement le développement du phytoplancton et avec lui l'ensemble de la chaine trophique. Toutefois les relations entre la distribution des proies et celle des prédateurs sont encore loin d'être bien connues pour la plupart des espèces marines. C'est en particulier le cas pour l'éléphant de mer austral (EDM) dont les proies souvent localisées à grandes profondeurs. Cette thèse s’est intéressée à étudier comment le comportement de plongée et de chasse des EDM est influencé par les variations à fine échelle de l'environnement. Une des originalités de cette thèse a été d’utiliser les mesures à très haute résolution récoltées par les éléphants de mer qui constituent un jeu de données 3-D in-situ unique à sous-mésoéchelle, puis de les combiner aux mesures satellites plus classiques de température et d'altimétrie. Ce travail a montré, pour la première fois à l’aide de données in-situ très haute résolution, l’importance des zones frontales à sous-mésoéchelle dans le comportement alimentaire d’un prédateur supérieur. De plus, elle a permis le développement d’une méthode originale d’identification des zones frontales à fine échelle et confirmé la pertinence de la méthode Quasi-Géostrophique de Surface (SQG) dans l’étude de la dynamique fine échelle, notamment dans les perspectives des futures missions spatiales à hautes résolutions (de type SWOT). / Ocean dynamics, especially in the southern ocean, are caracterized by strong fluctuation due to mesoscale (eddies, 100-200km) and submesoscale (filaments, <50km) processes. Theses processes are known to strongly stimulate primary production and with him the rest of the trophic chain. However, in marine ecosystems, relationship between prey and predator distribution remain challenging to understand. Such complexe link exist within the Southern Elephant Seal (SES) and their deep diving prey.This PhD worked to understand how the SES diving and foraging behaviour is impacted by submesoscale variation of the environment. Two original aspects of this work was first to use the very high resolution measurement from SES as an unique 3-D in-situ submesoscale dataset and then to combine it to, more classic, satellite temperature and altimetry measurement. This work showed, for the first time the in-situ impact of submesoscale frontal regions on one top predator foraging behaviour. Furthermore, during this study, an original method to identify fine scale frontal regions was developped. Finally, this PhD confirm the relevant use of the Surface Quasi-Geostrophic method in the study of fine scale dynamics, especially in the possibility of high resolution spatial missions (such as SWOT).

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