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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.
261

Caesar's invasion of Britain / Nathan Braman

Braman, Nathan, University of Lethbridge. Faculty of Arts and Science January 2011 (has links)
This paper examines the Roman invasions of and interactions with Britain in the mid first century BCE and early first century CE and evaluates the results. Specifically, this paper analyzes motives and the actual military events of the invasions of Julius Caesar in 55 and 54 BCE and evaluates their aftermath, leading up to the invasion of Claudius in 43 CE. Caesar’s stated motive for launching the invasion was to prevent the islanders from interfering in the new Roman order being constructed in Gaul. However, as will be shown, Caesar’s more personal motives, in the form of a desire for wealth and glory, played as much if not more of a role in the launching of these expeditions. In light of these motives, the invasions can be defined, at best, as partial successes. The Romans militarily defeated the enemy but failed to materially benefit from that victory. Caesar’s account also leaves numerous points of scholarly debate unresolved on the surface, but a careful examination of the evidence allows us to answer them in part. This paper provides a thorough discussion of this interesting period as well as a look at the motives, actions, and fortunes of the participants. iii / vi, 148 leaves ; 29 cm
262

The influence of Acacia Mearnsii invasion on soil properties in the Kouga Mountains, Eastern Cape, South Africa

Van der Waal, Benjamin Wentsel January 2010 (has links)
The invasion of Acacia mearnsii in the Kouga catchment, Eastern Cape, South Africa, has various negative impacts on the ecosystem. These impacts include: reduced species richness, increased water use, increased nutrients and increased N cycling rates. The native shrubby fynbos vegetation has adapted to the acidic nutrient poor soils and Mediterranean climate of the Kouga Mountains. Fynbos, however, is currently being out competed by the much taller Acacia mearnsii trees, due to their competitive nature and ability to fix nitrogen, thereby enriching the soil. The invaded sections of the valley bottoms and lower hill slopes are characterised by an almost complete monoculture of Acacia mearnsii, with very few fynbos species still present. The Department of Water and Environmental Affairs sponsored Working for Water programme started clearing Acacia mearnsii in 1996 in the Kouga Mountains. Cleared sites have remained bare for long periods, indicating that soil properties are not favourable for indigenous propagule re-establishment. The aim of this research was to assess how A. mearnsii invasion and clearing affect fynbos recovery through its impact on soils. This was done by characterising vegetation and soil properties on fynbos, infested and cleared slopes. Vegetation cover for various growth forms was determined and a species list was compiled for each plot. The slope angle, surface hardness, litter cover, bare ground cover and soil depth were measured in the field, whereas water repellency, particle size and the chemical composition were measured in the laboratory. Furthermore, the plant establishment capacity of soils from fynbos, infested and cleared slopes was calculated. This was done by germinating fynbos seeds and growing fynbos plants in soils from the various slopes. The effect that invasion and clearing has on soil erosion was quantified using erosion plots on fynbos, infested and cleared slopes. The invasion and clearing of Acacia mearnsii led to an increase in soil nutrients, especially nitrogen, phosphorus, potassium, carbon and manganese. Furthermore, soils became more acidic, with increased water repellency and reduced surface hardness. The vegetation changed to a tree-dominated structure, replacing the native species. Native plant germination was relatively unaffected by invasion and clearing, with an increase in germination just after clearing. Plant growth of a native grass, Themeda triandra, and herb, Helichrysum umbraculigerum, has increased on soils from cleared slopes. This study showed that soil movement increased on slopes which are invaded and cleared of Acacia mearnsii, with erosion rates doubling on invaded slopes
263

Hybridation et dynamique des populations chez les renouées du Japon: Espèces non-indigènes invasives du genre Fallopia Adans. (Polygonaceae) en Belgique / Hybridization and dynamics of populations of the Japanese knotweeds: Alien invasive species of the genus Fallopia (Polygonaceae) in Belgium

Tiébré, Marie-Solange 24 October 2007 (has links)
The Japanese knotweeds are invasive alien clonal species originating in Asia (Japan, Korea, Taiwan and Nord of China). They were introduced in Europe at the beginning of the 19th century. They are now some of the most troublesome invasive alien species in Europe and in the United States. In Belgium, a complex of four taxa and a hybrid represents them. All these taxa take part in the pattern of invasion and represent an excellent opportunity for studies of population biology in Western continental Europe. The presence from at least three taxa and a hybrid is confirmed by cytological, genetic and morphological studies. Vegetative reproduction is recognized as the main mode of reproduction and expansion of these taxa in the introduce range. However, interspecific hybridization events are observed confirming the restoration of the sexual reproduction by hybridization within this complex species in Belgium. Hybrid F. x bohemica with various ploidy levels from tetraploid to octoploid is observed. An increase in genotypic and morphological diversity is shown at the hybrid F. x bohemica which missed with the parental species. This could increase the potential of Japanese knotweeds to adapt to the new environment and contribute to the invasive success of these taxa in Belgium. Assignment test indicates a genetic pool differentiated at the hybrid F. x bohemica and not a mixture of the genetic pool of the parental species as expected for hybrid taxa. Hybrid F. x bohemica has always been considered as rare in Belgium and of horticultural origin. An analysis of the spatial distribution shows that hybrid F. x bohemica is widespread in Belgium and that its abundance depends on the areas. An analysis of extent of differentiation between groups of hybrid geographically distant could not provide proof of an independent evolution of hybrid populations under limited gene flow. An analysis of the sexual reproduction capacity and dispersal of seeds shows important production of viable seeds and consequent seed rain. Hybrid seeds may be dispersed beyond 16m, leading the possibility of founding new individuals and to contribute to the invasive success of these taxa. However, a trend towards decreasing germination rate is shown after a cold period. An analysis of the distribution at the landscape scale shows that the dynamics of colonization of habitats patches by Japanese knotweeds rising mainly from clonal propagation in spite of important pressure of propagule. The knotweeds prefer human disturbed habitats with a clear prevalence of communication routes. This leads the possibility of dispersing towards the adjacent habitats patches. A high dynamics of establishment of propagule was not observed at the hybrid plants compared with the parents plants in spite of the increase in genotypic diversity and the consequent pressure of propagule. Lastly, proposals for the integrated management of these taxa are proposed in the Belgium context. Their management will have first to identify hybrids and taxa involved. Emasculation and management of the existing clones represent solutions to prevent flowering and expansion of these taxa. An active management of disturbed habitats may represent alternative to prevent the invasion by Japanese knotweeds / Les renouées du Japon sont des espèces clonales non-indigènes originaires dAsie (Japon, Corée, Taiwan et Nord de la Chine). Elles ont été introduites en Europe au début du 19è siècle. Elles font désormais partie des espèces non-indigènes les plus invasives en Europe et aux Etats Unis. En Belgique, elles sont représentées par un complexe de quatre taxons et un hybride. Tous ces taxons participent à la dynamique dinvasion et représentent un modèle dintérêt pour les études de biologie des populations en Europe continentale occidentale. La présence dau moins trois taxons et un hybride est confirmée par des études cytologiques, génétiques et morphologiques. La reproduction végétative est reconnue comme le principal mode de reproduction et dexpansion de ces taxons dans la zone dintroduction. Toutefois, des phénomènes dhybridation interspécifique sont observés confirmant la restauration de la reproduction sexuée par hybridation au sein de ce complexe despèces en Belgique. Lhybride F. x bohemica avec différents niveaux de ploïdie, du tétraploïde à loctoploïde, est observé. Un accroissement de la diversité génotypique et morphologique qui manquait aux espèces parents est démontré chez lhybride F. x bohemica. Ceci pourrait augmenter le potentiel des renouées du Japon à sadapter au nouvel environnement et contribuer au succès invasif de ces taxons en Belgique. Un test dassignation indique un pool génétique différencié chez lhybride F. x bohemica et non un mélange du pool génétique des espèces parentales comme attendu dans le cadre de taxons hybrides. Lhybride F. x bohemica a toujours été considéré comme rare en Belgique et dorigine horticole. Une analyse de la répartition spatiale montre que lhybride F. x bohemica est très répandu en Belgique et que son abondance dépend des régions. Une analyse de létendue de la différenciation entre groupes dindividus hybrides géographiquement distants na pas pu fournir de preuve dune évolution indépendante des populations hybrides sous un flux de gènes limité. Une analyse de la capacité de reproduction sexuée et de dispersion des graines démontre une production importante de graines viables et une pluie de graines conséquente. Les graines hybrides sont capables de se disperser à plus de 16m, laissant la possibilité de fonder de nouveaux individus et de contribuer au succès invasif de ces taxons. Cependant, une tendance à la diminution du potentiel de germination est observée après une période de froid chez ces taxons. Une analyse de la distribution à léchelle du paysage a permis dinterpréter la dynamique de colonisation des taches dhabitats par les renouées du Japon comme relevant principalement de la propagation clonale malgré une pression de propagule importante. Les renouées du Japon préfèrent les habitats perturbés par lhomme avec une nette prédominance des réseaux linéaires de communications. Ceci laisse ensuite la possibilité de se disperser vers les taches dhabitats adjacents. Une dynamique détablissement de propagules plus importante na pas été observée chez les plants hybrides comparées aux plants parents malgré laccroissement de diversité génotypique et la pression de propagules considérable. Enfin, des pistes pour la gestion intégrée des renouées du Japon en Belgique sont proposées. Cette gestion devra en priorité identifier les hybrides et les taxons en présence. Des mesures démasculation et de gestion des clones existants pourraient constituer une solution pour empêcher la floraison et lexpansion de ces taxons. Une gestion active des habitats perturbés pourrait représenter une alternative pour prévenir linvasion par les renouées du Japon
264

Ursachen des Invasionserfolges von Rhododendron ponticum L. auf den Britischen Inseln: Einfluss von Habitat und Genotyp / The invasion success of Rhododendron ponticum L. in the British Isles: effects of habitat and genotypes

Erfmeier, Alexandra 27 April 2004 (has links)
No description available.
265

Aspects of ancient Near Eastern chronology (c. 1600-700 BC)

Furlong, Pierce James January 2007 (has links) (PDF)
The chronology of the Late Bronze and Early Iron Age Near East is currently a topic of intense scholarly debate. The conventional/orthodox chronology for this period has been assembled over the past one-two centuries using information from King-lists, royal annals and administrative documents, primarily those from the Great Kingdoms of Egypt, Assyria and Babylonia. This major enterprise has resulted in what can best be described as an extremely complex but little understood jigsaw puzzle composed of a multiplicity of loosely connected data. I argue in my thesis that this conventional chronology is fundamentally wrong, and that Egyptian New Kingdom (Memphite) dates should be lowered by 200 years to match historical actuality. This chronological adjustment is achieved in two stages: first, the removal of precisely 85 years of absolute Assyrian chronology from between the reigns of Shalmaneser II and Ashur-dan II; and second, the downward displacement of Egyptian Memphite dates relative to LBA Assyrian chronology by a further 115 years. Moreover, I rely upon Kuhnian epistemology to structure this alternate chronology so as to make it methodologically superior to the conventional chronology in terms of historical accuracy, precision, consistency and testability.

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