Autographed copy. / At head of title: Missions au Sahara (1915-1918).

Autographed copy. / At head of title: Missions au Sahara (1915-1918).

Th. 3e cycle--Etud. polit.--Paris 2, 1984.

Thèse--Lettres--Paris, 1975. / Bibliogr. p. 893-904 . Index.

For over 30 years now, the Polisario Front has led the Sahrawi struggle for independence in Western Sahara. Following Spanish decolonization of the territory in 1976, Morocco claimed the territory of Western Sahara leading to a protracted war against the Polisario Front. The 1991 United Nations brokered ceasefire agreement prompted the Polisario to switch from warfare as its main tactic to leveraging international support for Sahrawi self-determination and raising awareness of the conflict. This paper discusses how the international community helps the Polisario Front gain recognition for its cause, the Polisario Front’s tactics for leveraging international support, and the limits of relying on the international community. / text

Inaug.-diss.-Jena.

Astragalus gombo Bunge (Fabaceae) est une plante bien représentée dans le Sahara Septentrional Est Algérien (région de Ouargla, Algérie) et couramment utilisée comme fourrage pour les animaux ou en médecine traditionnelle. Malgré de nombreuses publications sur la richesse en polysaccharides d’autres espèces appartenant au genre Astragalus et la description de leurs propriétés biologiques putatives ou avérées, aucune étude ne s’est intéressée à l’espèce gombo. L’objectif de ce travail de thèse a donc été de réaliser des investigations sur plusieurs parties de cette plante en vue d’extraire, identifier et caractériser son contenu en polysaccharides. Dans un second temps les propriétés biologiques et rhéologiques de ces polymères ont été étudiées afin d’identifier d’éventuelles voies de valorisation. Les résultats obtenus ont permis de détecter la présence de composés pectiques et hémicellulosiques dans la tige d’Astragalus gombo et celle d’un galactomannane dans les graines. Le galactomannane est de haute masse moléculaire (1,1x106 Da) et est constitué d’une chaine principale de β-(1→4)-D-mannane ramifiée en α-(1→6) par des résidus Dgalactopyranoses avec un rapport M/G de 1,7. La caractérisation de ses propriétés rhéologiques a révélé un comportement typique rhéofluidifiant et des propriétés viscoélastiques. L’étude des activités biologiques associées à ce biopolymère a révélé son potentiel comme prébiotique et antioxydant. / Astragalus gombo Bunge (Fabaceae) is a terrestrial plant occuring in the East Septentrional Sahara (Ouargla, Algeria). It is commonly used as fodder or in traditional medicine by local populations. Despite numerous publications focusing on polysaccharidic contents of Astragalus species and the designation of their putative or proved biological activities, no study has examined those of A. gombo. The objective of this thesis was firstly to investigate several organs of this plant for their polysaccharide contents. In a second step, the biological and rheological properties of these biopolymers have been studied to identify ways of adding value. Results led to the identification of pectic compounds and hemicelluloses in the rods of Astragalus gombo whereas a galactomannan was detected in its seeds. This galactomannan was a high molecular weight macromolecule composed of a β-(1→4)-D-mannan skeleton ramified by residues of D-galactopyranoses. The M/G ratio was of 1.7. The characterization of its rheological behavior was typic of that of a rheofluidifiant fluid with viscoelastic properties. The study of its biological properties showed its potential as prebiotic and antioxidant agent.

No description available.

Traditional stylistic classifications have not provided conclusive dates for the rock art of the Sahara, and the imagery can therefore not be placed securely in its cultural or environmental context. This thesis proposes a new methodology in which content and patina of the engravings are used to establish a chronological sequence, against the background of changing palaeoenvironmental conditions. This framework can then be used to explore aspects of the relationship between the rock art and the changing Holocene landscape. The engravings of the Wadi al‐Hayat, which were recently recorded by the Fezzan Rock Art Project, form the basis of this research. A total of 2466 images of animals were individually analysed and entered into a database. The depicted species are shown to reflect the local fauna, and their habitats coincide with the palaeoclimatic conditions of the central Sahara. Additionally, recent geomorphological analyses of the rock surfaces of the Messak provide a chronology for the patina, and show that the formation of each type of patina was dependent on environmental conditions. Through analyses of the animal engravings, categorised according to positively identifiable species and patina types, this thesis demonstrates a direct correlation between the content (i.e. species depicted) and patina of the engravings, and the palaeoenvironment. Both content and patina of the engravings indicate a development from wet savanna to dry savanna, and finally to desert conditions, consistent with the Holocene climatic sequence. This provides a chronological framework for the engravings and places them into a palaeoenvironmental context. The locations of the engravings of each patina group also correspond to the changing lake levels of the al‐Hayat palaeolake identified in previous palaeoenvironmental research projects, which in turn supports the chronology of the engravings. Through spatial analyses, the locations and landscapes preferred by the engravers for the creation of rock art can be identified, whilst the new chronological sequence allows us to explore changes in the cultural conventions that underlie the creation of the engravings. As well as providing a chronological framework and environmental context for the engravings for the Wadi al‐Hayat, the research presented in this thesis therefore has the potential to change our understanding of Saharan rock art.

Thèse--Sc. nat.--Paris. / Bibliogr. p. 294 à 310. Index.