Search results for "IP"
showing 10 items of 57540 documents
Submarine morphology of the Comoros volcanic archipelago
2021
co-auteur étranger; International audience; A detailed morpho-bathymetric study of the Comoros archipelago, based on mostly unpublished bathymetric data, provides a first glimpse into the submarine section of these islands. It offers a complete view of the distribution of volcanic structures around the archipelago, allowing to discuss the origin and evolution of this volcanism. Numerous volcanic cones and erosional-depositional features have been recognized throughout the archipelago. The magmatic supply is focused below one or several volcanoes for each island, but is also controlled by lithospheric fractures evidenced by volcanic ridges, oriented along the supposed Lwandle-Somali plate bo…
Soil erosion processes in European vineyards: A qualitative comparison of rainfall simulation measurements in Germany, Spain and France
2016
Small portable rainfall simulators are considered a useful tool to analyze soil erosion processes in cultivated lands. European research groups in Spain (Valencia, Málaga, Lleida, Madrid and La Rioja), France (Reims) and Germany (Trier) have used different rainfall simulators (varying in drop size distribution and fall velocities, kinetic energy, plot forms and sizes, and field of application) to study soil loss, surface flow, runoff and infiltration coefficients in different experimental plots (Valencia, Montes de Málaga, Penedès, Campo Real and La Rioja in Spain, Champagne in France and Mosel-Ruwer valley in Germany). The measurements and experiments developed by these research teams give…
Climate change: A driver of future conflicts in the Persian Gulf Region?
2021
Ongoing global change and its direct environmental impacts, in addition to securing economic transition to the post-oil era, could trigger complex socio-economic and political crises in oil-dependent economies of the Persian Gulf Region (PGR). To evaluate the role of climate change and related policies in degrading the environment and its socio-economic impacts in the PGR, we have used a variety of available global datasets and published data. The results show that the countries of the PGR pursue some types of socio-economic reforms to alleviate the impacts of climate change. However, it seems that these attempts are not compatible with the environment's capacity. The main problem stems fro…
Shear zone junctions: Of zippers and freeways
2017
Abstract Ductile shear zones are commonly treated as straight high-strain domains with uniform shear sense and characteristic curved foliation trails, bounded by non-deforming wall rock. Many shear zones, however, are branched, and if movement on such branches is contemporaneous, the resulting shape can be complicated and lead to unusual shear sense arrangement and foliation geometries in the wall rock. For Y-shaped shear zone triple junctions with three joining branches and transport direction at a high angle to the branchline, only eight basic types of junction are thought to be stable and to produce significant displacement. The simplest type, called freeway junctions, have similar shear…
A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation
2011
The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1ĝ€‰au is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 ut. The event is consistent with a spherical shape for Eris, with radius 1,163±6 kilometres, density 2.52±0.05 grams per cm 3 and a high visible geometric albedo,. No nitro…
Evidence of organic contamination in urban soils of Cotonou town (Benin).
2012
14 pages; International audience; In Cotonou (Benin), growth of the population leads to an excessive use of natural resources, inducing organic contaminations. Surface soils collected in the town, were extracted and fractionated by liquid chromatography in three families: aliphatic, aromatic hydrocarbons and polar fractions. Each fraction was characterized by gas chromatography-mass spectrometry. All the results show that an anthropogenic input exists (waste oils). Indeed, aliphatic hydrocarbons have specific markers emphasizing the presence of petrogenic products: UCM (unresolved complex mixture), specific distribution of pentacyclic triterpane. However, specific molecular biomarkers revea…
Soil moisture modelling of a SMOS pixel: interest of using the PERSIANN database over the Valencia Anchor Station
2010
In the framework of Soil Moisture and Ocean Salinity (SMOS) Calibration/Validation (Cal/Val) activities, this study addresses the use of the PERSIANN-CCS<sup>1</sup>database in hydrological applications to accurately simulate a whole SMOS pixel by representing the spatial and temporal heterogeneity of the soil moisture fields over a wide area (50×50 km<sup>2</sup>). The study focuses on the Valencia Anchor Station (VAS) experimental site, in Spain, which is one of the main SMOS Cal/Val sites in Europe. <br><br> A faithful representation of the soil moisture distribution at SMOS pixel scale (50×50 km<sup>2</sup>) requires an accurate estimation…
Growth of stylolite teeth patterns depending on normal stress and finite compaction
2007
Abstract Stylolites are spectacular rough dissolution surfaces that are found in many rock types. They are formed during a slow irreversible deformation in sedimentary rocks and therefore participate to the dissipation of tectonic stresses in the Earth's upper crust. Despite many studies, their genesis is still debated, particularly the time scales of their formation and the relationship between this time and their morphology. We developed a new discrete simulation technique to explore the dynamic growth of the stylolite roughness, starting from an initially flat dissolution surface. We demonstrate that the typical steep stylolite teeth geometry can accurately be modelled and reproduce natu…
Interpolation par régressions locales : application aux précipitations en France
2009
Interpolation by local regressions applied to precipitation in France. Two interpolation methods are presented. The global one operates by means of a regression processing applied on the complete data set and the local one consists in a regression processing applied individually to many local sets made of recording stations each. The procedure is applied to the amount of precipitation in France. The local interpolation provides better results than the global one. The contradictory effects between crest lines and plains close below which are drier are well shown by the local model. This one allows other indicators from the regressions which interpretation provides keys for understanding how …
Indigenous people’s responses to drought in northwest Bangladesh
2019
Abstract Bangladesh is highly disaster-prone, with drought being a major hazard which significantly impacts water, food, health, livelihoods, and migration. In seeking to reduce drought vulnerabilities and impacts while improving responses, existing literature pays limited attention to community-level views and actions. This paper aims to contribute to filling in this gap by examining how an indigenous group, the Santal in Bangladesh’s northwest, responds to drought through local strategies related to water, food, and migration which in turn impact health and livelihoods. A combination of quantitative data through a household survey and qualitative data through participatory rural appraisal…