Search results for "Universe"
showing 10 items of 2171 documents
Determinants of the interannual relationships between remote sensed photosynthetic activity and rainfall in tropical Africa
2007
International audience; The response of photosynthetic activity to interannual rainfall variations in Africa South of the Sahara is examined using 20 years (1981-2000) of Normalised Difference Vegetation Index (NDVI) AVHRR data. Linear correlations and regressions were computed between annual NDVI and annual rainfall at a 0.5° latitude/longitude resolution, based on two gridded precipitation datasets (Climate Prediction Center Merged Analysis of Precipitation [CMAP] and Climatic Research Unit [CRU]). The spatial patterns were then examined to detect how they relate to the mean annual rainfall amounts, land-cover types as from the Global Land Cover 2000 data set, soil properties and soil typ…
Dynamics of hydrofracturing and permeability evolution in layered reservoirs
2015
International audience; A coupled hydro-mechanical model is presented to model fluid driven fracturing in layered porous rocks. In the model the solid elastic continuum is described by a discrete element approach coupled with a fluid continuum grid that is used to solve Darcy based pressure diffusion. The model assumes poro-elasto-plastic effects and yields real time dynamic aspects of the fracturing and effective stress evolution under the influence of excess fluid pressure gradients. We show that the formation and propagation of hydrofractures are sensitive to mechanical and tectonic conditions of the system. In cases where elevated fluid pressure is the sole driving agent in a stable tec…
Procedures and protocol for soil biodiversity monitoring : ‘RMQS-Biodiv', a french pilot area experience.
2008
PosterFR2116Poster
Evolution des paysages Sahélines au cours des six dernières décennies dans la région de Niamey : de la disparition de la brousse tigrée à l'encroutem…
2010
In the Sahel, the rapid increase of the population during the last decades and the climate variation lead to an important environmental degradation. This work aims to measure the impacts of the human pressure on ecosystem during the six last decades. A diachronic cartography of a 100 km² area close to Niamey was done with aerial photographs (1950 and 1975) and GPS measurements (2009). Results showed that the tiger bush vegetation was completely cleared between 1950 and 2009 while the fallow decreases from 7 % to 1 %. In the sandy valley, the increase of cultivated fields from 20,7 % (1950) to 69,4 % (1975) favoured wind and water erosions which allowed surface soil crusting. Between 1975 an…
Stratigraphie séquentielle et architecture sédimentaire haute résolution de l'Oolithe Blanche du Bassin Parisien
2013
La formation carbonatée de l'Oolithe Blanche (Bathonien) du Bassin de Paris est, avec le Trias, un aquifère salin profond majeur qui présente un potentiel réservoir important et reconnu, notamment via l'exploitation géothermique ou les grands projets de recherche dans le domaine du stockage géologique du CO2. Elle a été largement étudiée d'un point de vue sédimentologique et stratigraphique en particulier sur les affleurements de Bourgogne (Floquet et al., 1989 ; Garcia et Sambet, 1994 ; Gaumet et al., 1996 ; Gaumet, 1997). Ces études ont permis de définir un profil de dépôt de type rampe carbonatée qui varie entre une rampe ouverte et une rampe barrée, permettant le développement d'un doma…
Stress sensitivity of stylolite morphology
2009
International audience; Stylolites are rough surfaces that form by localized stress-induced dissolution. Using a set of limestone rock samples collected at different depths from a vertical section in Cirque de Navacelles (France), we study the influence of the lithostatic stress on the stylolites morphology on the basis of a recent morphogenesis model. We measured the roughness of a series of bedding-parallel stylolites and show that their morphology exhibits a scaling invariance with two self-affine scaling regimes separated by a crossover-length (L) at the millimeter scale consistent with previous studies. The importance of the present contribution is to estimate the stylolite formation s…
Constructing a Transmedia Universe : The Case of Battlestar Galactica
2021
In this article, we define a ‘transmedia universe’ as encompassing the complexity of transmedia storytelling, production and consumption. In doing so, we use the popular science fiction television series Battlestar Galactica as a case study, including both the original and reimagined versions of the series and their various intramedia and transmedia, narrative and non-narrative, and diegetic and non-diegetic expansions. Moreover, we look beyond the official productions of the Battlestar Galactica franchise and include, for example, user-generated content within its transmedia universe. peerReviewed
Fate of organic pollutants after sewage sludge spreading on agricultural soils: a 30-years field-scale recording
2006
Le DOI mentionné dans l'article 10.2166/WPT.2007.008 ne fonctionne pas; International audience; Toxic organic compounds, such as the surfactants linear alkylbenzene sulfonates (LAS) and nonylphenol polyethoxylates (NPE), Polycyclic aromatic hydrocarbons (PAH) and residues derived from plastics (PAE-phthalates) end up in sewage sludge. In order to evaluate and quantify the potential environmental risks associated with the xenobiotic introduction into biological life cycle, the EU BIOWASTE project (QLK5-CT-2002-01138) devotes one task to the study of the fate of xenobiotic in a sandy soil after sludge spreading on a 30-year field-scale record experiment. Experimental maize crop fields from Bo…
On-Orbit Degradation of Solar Instruments
2013
International audience; We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was to open discussions related to the degradation observed in Sun-observing instruments exposed to the effects of the space environment. This article summarizes the various lessons learned and offers recommendations to reduce or correct expected degradation with the goal of increasing the useful lifespan of future and ongoing s…
The close classical T Tauri binary V4046 Sgr: Complex magnetic fields & distributed mass accretion
2011
We report here the first results of a multi-wavelength campaign focussing on magnetospheric accretion processes within the close binary system V4046 Sgr, hosting two partly-convective classical T Tauri stars of masses ~0.9 Msun and age ~12 Myr. In this paper, we present time-resolved spectropolarimetric observations collected in 2009 September with ESPaDOnS at the Canada-France-Hawaii Telescope (CFHT) and covering a full span of 7d or ~2.5 orbital/rotational cycles of V4046 Sgr. Small circularly polarised Zeeman signatures are detected in the photospheric absorption lines but not in the accretion-powered emission lines of V4046 Sgr, thereby demonstrating that both system components host lar…