Search results for "Nature"
showing 10 items of 1564 documents
Risques naturels et technologiques
1996
Le risque naturel ou technologique n'existe, pour la collectivité, que s' il présente un coût humain et/ou financier. L'information préventive est une obligation légale. Chaque préfet a en charge la constitution d'un dossier d'information et de sensibilisation sur les risques majeurs, naturels ou technologiques, reconnus sur le territoire de son département en collaboration avec les acteurs régionaux réunis au sein d'une cellule d'analyse des risques et d'information préventive (CARIP). La récente parution des dossiers départementaux des risques majeurs (DDRM) offre une vision synthétique des principaux risques. La base de données ainsi constituée fournit un éclairage intéressant sur les ri…
Towards a framework for assessment and management of cumulative human impacts on marine food webs
2015
Effective ecosystem-based management requires understanding ecosystem responses to multiple human threats, rather than focusing on single threats. To understand ecosystem responses to anthropogenic threats holistically, it is necessary to know how threats affect different components within ecosystems and ultimately alter ecosystem functioning. We used a case study of a Mediterranean seagrass (Posidonia oceanica) food web and expert knowledge elicitation in an application of the initial steps of a framework for assessment of cumulative human impacts on food webs. We produced a conceptual seagrass food web model, determined the main trophic relationships, identified the main threats to the fo…
The Role of Excited Oxygen Molecules in the Formation of the Secondary Ozone Layer at 87 to 97 km
2018
The secondary ozone layer is located at elevations of 87 to 97 km in the upper mesosphere – lower thermosphere. It overlaps with the ionospheric D-layer. Daytime intensive UV radiation is dissociating O2 molecules to O atoms and photoexcitating O2 molecules up to 11.07eV level. Ozone photolysis between the wavelengths of 118.7–121.6 nm produces three oxygen atoms from one ozone molecule. Collision reactions of O2(B3 Σu —) and O2(X3 Σg —, υ≥26) with O2(X3 Σg —, υ=0) produce additional oxygen atoms. The number of oxygen atoms is maintained at such a high level that a small but significant ozone concentration survives. UV radiation weakens radically during the night. The number of O atoms show…
Dynamics of soil organic matter pools after agricultural abandonment
2014
Changes of land use from croplands to natural vegetation usually increase Carbon (C) stocks in soil. However, the contribution of old and new C to various pools still is not clearly analyzed.We measured the 13C signature of soil organic carbon (SOC) pools after vegetation change from vineyard (C3) to grassland (C4) under Mediterranean climate to assess the changes of old and new C in total SOC, microbial biomass (MB), dissolved organic C (DOC), and CO2 efflux from soil. Development of the perennial grass Hyparrhenia hirta (C4) on vineyard abandoned for 15 or 35 years ago increased C stocks for 13% and 16%, respectively (in the upper 15 cm). This increase was linked to the incorporation of n…
L'éveil des sens et la nature complice chez Zola et Maupassant
2020
The paper discusses the problem of the awakening of senses and sensuality, with a visible connivance of nature, in characters of two novels belonging to the Realist/Naturalist movement. In Emile Zola’s The Sin of Father Mouret (1875), a fanatic priest having forgotten his clerical condition falls in love with a virgin girl who grew up in a savage garden. They are both involved in an erotic game set up by plants and animals living in the garden that want them to know the carnal aspect of love and push them to a physical close-up. In this way, the garden, named the Paradou, becomes both a kind of new Eden and an inferno of lust. In Guy de Maupassant’s Mont-Oriol (1887), a young and naïve aris…
Effets du bruit marin sur le changement des poissons sparidés juvéniles entre les espèces et les stades de développement
2023
International audience; Marine noise is an emerging pollutant inducing a variety of negative impacts on many animal taxa, including fish. Fish population persistence and dynamics rely on the supply of early life stages, which are often very sensitive to disturbance. Impacts of marine noise pollution (MNP) on juvenile fish have rarely been investigated in temperate regions. This is particularly true for the Mediterranean Sea, which is considered as an MNP hotspot due to intensive maritime traffic. In this study, we investigate the relationship between MNP related to boat traffic and (i) assemblage structure and (ii) the density of juvenile fishes (post-settlers at different stages) belonging…
Sex-specific signatures of intrinsic hippocampal networks and regional integrity underlying cognitive status in multiple sclerosis
2021
Abstract The hippocampus is an anatomically compartmentalized structure embedded in highly wired networks that are essential for cognitive functions. The hippocampal vulnerability has been postulated in acute and chronic neuroinflammation in multiple sclerosis, while the patterns of occurring inflammation, neurodegeneration or compensation have not yet been described. Besides focal damage to hippocampal tissue, network disruption is an important contributor to cognitive decline in multiple sclerosis patients. We postulate sex-specific trajectories in hippocampal network reorganization and regional integrity and address their relationship to markers of neuroinflammation, cognitive/memory per…
Sexes in gynodioecious Geranium sylvaticum do not differ in their isotopic signature or photosynthetic capacity
2017
In gynodioecious plants, females are expected to produce more or better seeds than hermaphrodites in order to be maintained within the same population. Even though rarely measured, higher seed production can be achieved through differences in physiology. In this work, we measured sexual dimorphism in several physiological traits in the gynodioecious plant Geranium sylvaticum. Photosynthetic rate, stomatal conductance, transpiration rate, WUE and isotopic signatures were measured in plants growing in two habitats differing in light availability. Females have been reported to produce more seeds than hermaphrodites. However, we did not observe any significant difference in seed output between …
Beware of contagion!
2003
Landscape ecology starts from the assumption that diversity and spatial arrangement of ecosystem mosaics has ecological implications and tries to understand the interactions between diversity and structure of large spatially heterogeneous areas and its ecological functions. This approach implies effective use of earth observation techniques and geographic information systems, enabling a global view of the landscape mosaics. Consequently, a large number of indices has been used to quantify the structure of categorical maps as a surrogate of actual landscapes and correlate them to ecological processes. In particular, the entropy-based contagion index has been extensively used to summarize the…
Les stratégies doxales dans les signatures publicitaires de marque
2015
International audience