Search results for "Universe"
showing 10 items of 2171 documents
Nile Basin Climates
2009
The climate of the Nile Basin is characterised by a strong latitudinal wetness gradient. Whereas the areas north of 18°N remain dry most of the year, to the south there is a gradual increase of monsoon precipitation amounts. Rainfall regimes can be divided into 9 types, among which summer peak regimes dominate. In the southern half of the basin, mesoscale circulation features and associated contrasts in local precipitation patterns develop as a result of a complex interplay involving topography, lakes and swamps. Precipitation changes and variability show up as 3 distinct modes of variability. Drying trends since the 1950s are found in central Sudan and to some extent the Ethiopian Highland…
Interaction between the West African Monsoon and the summer Mediterranean climate: An overview.
2013
15 pages; International audience; Although in the framework of the global climate research the Mediterranean climate variability andthe West African Monsoon (WAM) dynamics have been considered for a long time as “passive”systems, i.e., prone to the influence of large scale ocean and atmospheric variability, over the lastdecade many studies have been dedicated to the WAM-Mediterranean interaction and the active roleof these climate systems has been highlighted. This article presents the WAM-Mediterraneanteleconnection through an overview of the recent literature, describing the observational evidencesand the dynamical mechanisms underlying this climate teleconnection. The influence of the Me…
Evolutionary and developmental hypotheses in rodent dentition through time : the adaptive radiation of Arvicolinae (Rodentia)
2014
The evolution of mammalian dentition is defined by profound morphological modifications as occlusion and heterodonty. Among rodents, characterized by a reduced dental formula, arvicolines have a highly derived dentition, with prismatic and hypsodont molars. The aim of this Ph.D thesis is to explore various morphological innovations through developmental and adaptive aspects. Geometric morphometric methods were used on molars, incisors and mandibles to investigate the dynamics of development and evolution of dentition. A developmental model predicting molar proportions is tested and confirmed for the rodent order; it could be also extended to the premolar. The relationship between dental mor…
Le genre Nucleolites (Echinoidea, Cassiduloidea) du Bajocien à l'Oxfordien dans le Bassin de Paris : apport des données architecturales à la systémat…
2005
International audience; La classification des espèces du genre Nucleolites de l'intervalle BajocienOxfordien du bassin de Paris est révisée. Une vision classique, jusqu'alors utilisée par les auteurs et fondée principalement sur la morphologie générale du test, est tout d'abord présentée. Elle est ensuite modifiée à partir de nouvelles données architecturales se référant au modèle extraxialaxial concernant la structure de l'appareil apical ainsi que la présence de plaques supplémentaires et de plaques caténales. Ces données architecturales sont considérées comme prioritaire vis-à-vis de la morphologie générale du test. Cette approche conduit à une nouvelle vision de la classification des …
L’audition chez les primates : entre forme, fonction, écologie et comportement
2019
The order Primates is composed of species whose morphologies, life history traits and behaviors are very diversified. The oldest representatives are dated about 65 million years. Because of this diversity, studies have focused on understanding the relationships between different parameters. Among the morphological structures studied, the basicranium, in particular the characters of the ear, have very often been considered in a phylogenetic perspective. Since the development of new acquisition techniques such as micro-tomography (μCT), new data are available. Thus, the interest for the morphology of the inner and middle ear, hitherto difficult to access, is growing. The structures of the ear…
Les passages à gué de la Grande Saône, approche archéologique et historique d'un espace fluvial (de Verdun-sur-le-Doubs à Lyon).
2002
National audience
Amendement et renouvellement des sols dans la viticulture bourguignonne aux XIVe et XVe siècles
2019
International audience
Méditerranée et mousson africaine : mécanismes et évolution dans l’actuel et le futur.
2014
6 pages; International audience; À partir d’observations in situ et analysées, de réanalyses atmosphériques, d’expériences numériques forcées parles températures de la Méditerranée, et de sorties CMIP5 issues de seize modèles couplés ayant participé au dernier exercicedu GIEC, nous tentons une synthèse des travaux collaboratifs entrepris au CRC ces cinq dernières années et portant sur lesinteractions tropiques/extra-tropiques au long du fuseau africain et sur leurs liens avec la mousson africaine. Après avoirrappelé le rôle des téléconnexions avec les grands bassins océaniques, de la circulation sur le secteur euro-atlantique et dela mousson indienne via le mécanisme de Rodwell-Hoskins, nou…
Time of emergence of Mediterranean summer maximum temperature.
2016
The time at which the signalof climate change emerges from the noise of natural climate variability is called “time of emergence”. This timeis analyzed here based on summertime mean maximum temperature in the Mediterranean basin for RCP8.5 andRCP4.5 scenarios. This time would be around 2040-50 (2060-70) in the eastern (western) basin. Differencesbetween the optimistic and pessimistic scenarios give a mean shift of around 15 years with the time ofemergence occurring earlier for RCP8.5 scenario.
Impact de la variabilité climatique et de la dynamique des états de surface sur les écoulements du bassin béninois du fleuve Niger
2007
This thesis has for principal objective to establish a diagnosis of the hydrological system of the beninese basin of the Niger River, in the context of the rainfall decrease which has severely affected Africa since the 1970s. To achieve this goal, this study was based on three main types of data :weather (rainfall, temperature, relative humidity, potential evapotranspiration, real evapotranspiration), hydrological (stream flow, recharge) and of land surface conditions (land cover types, NDVI).It considers three key aspects. The first one, devoted to the study of hydro-climatic variability over the period 1955- 1992, shows that the rainfall deficits of the 1970s and 1980s were largely amplif…