Texte remanié de: Th. 3e cycle--Paris 4, 1976.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1997. / Title from PDF title page (viewed on Apr. 2, 2005). Vita. Includes bibliographical references (p. 57-68).

No description available.

Cet article étudie les effets de la variabilité climatique sur les migrations de jeunes adultes au Madagascar. Des données panel et des données climatiques nous permettent d'étudier les effets des sécheresses sur les migrations internes d'une cohorte de jeunes malgaches provenant de régions rurales. Nous trouvons qu'une période de sécheresse diminue la probabilité qu'un individu migre l'année suivante. La possession d'actifs par le ménage de l'individu et l'accès à des véhicules d'épargne diminuent l'ampleur de cet effet, puisque la richesse et l'épargne peuvent tempérer la diminution du stock de ressources pouvant permettre la migration qui est causée par la sécheresse. De plus, on remarque que les jeunes adultes sont plus susceptibles de migrer lorsque leur ménage possède un nombre élevé de liens sociaux à l'extérieur de leur village. Nos résultats suggèrent que les contraintes de liquidité restreignant les jeunes migrants affectent plus fortement les jeunes femmes que les hommes. Ces derniers migrent généralement à la recherche d'un emploi, ce qui rapporte un meilleur rendement économique que les migrations motivées par le mariage et l'éducation effectuées par les jeunes femmes. Ainsi, les sécheresses restreignent les migrations des jeunes adultes par des facteurs aux effets hétérogènes selon le sexe des individus. / We analyze the impact of climate events on migration among a cohort of young adults residing in rural Madagascar. We find a strong negative impact of drought on the decision of youth to migrate in the year after the adverse weather shock. Household assets and access to savings institutions attenuate this impact, consistent with the notion that wealth and savings cushion the blow of the shock on the resources required to finance migration. We also find that households that report more social connections outside their villages are more likely to have their young adult members migrate. Our findings suggest that the liquidity constraints from climate shocks that prevent youth migration are more binding for young women who migrate largely for reasons of marriage and education. Males, in contrast, are more likely to migrate in search of employment, which often has higher economic returns than migration motivated by marriage and education. These factors likely explain why drought deters migration of young women, but not so for young men who still choose to migrate in search of a job.

Habilitationsschrift--Fachbereich Sozialwissenschaften--Universität Bremen, 1999. / Bibliogr. p. [235]-252. Index.

Texte remanié de: Thèse de doctorat--Géographie--Paris 4, 2002. / Bibliogr. p. 399-415. Glossaire.

Not available / text

Th.--Ethnol.--Starsbourg 2, 1985.

No description available.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The Cretaceous Ambohiby Complex is an alkaline ring complex located in the central part of Madagascar and covers a mountainous area of approximately 225km2. The complex intrudes into Precambrian basement gneisses and consists of the following rock types in a chronological order; gabbros, monzonite, alkali-syenite, micro-granite and granites. Both mafic and felsic rocks are dominated by sodic mineralogies. Pyroxenes are generally aegirine, aegirine-augite, and hedenbergite and commonly occur in granites, micro-granites, syenites and monzonite. In gabbros and mafic dykes, augite is the more common composition. Amphiboles are represented by bluish to brownish-green varieties with arfvedsonite to eckermannite compositions in granites, and magnesia-arfvedsonite compositions in micro-granites. Ferro-edenite is present in some alkali-syenites and monzonite. Feldspars are usually single phase and are therefore hypersolvus. In granites, micro-granites and alkali-syenites, path and string perthite is very common. Graphic intergrowth of quartz and alkali feldspars is also common in granites and some alkalisyenites. Major elements variation diagrams plotted against SiO2 indicate that the mafic and felsic rocks of the Ambohiby Complex were formed by processes similar to those of Fractional crystallization. Chondrite normalised mafic rocks have slightly positive Eu anomalies while the felsic rocks have negative Eu anomalies, indicating fractionation of plagioclase feldspars. The Chondrite normalised gabbroic rocks shared similar trends of heavy rare earth with Chondrite normalised Marion Hotspot data. This suggests that the basaltic parent magma for the Ambohiby Complex, possibly related to the Marion hotspot plume. The Fractional crystallization model with an inclusion of olivine in the mineral assemblage seems to fit very well with the actual Ambohiby felsic end member rocks (i.e. granites). It is therefore clear that differentiation mainly occurred by fractional crystallization but variable initial Sr and Nd values indicate the magmas assimilated crustal material during emplacement. The Rb-Sr geochronology gave an age of 90±2.4 Ma for the intrusion of the Ambohiby Complex, which confirms that the Ambohiby Complex is associated with the Gondwana break-up. In addition the Marion Hotspot plume is believed to have been located in the southern tip of the island at around 90 Ma ago.