Crisis? What crisis? : l'anthropisation du milieu et la biodiversité dans la Baie de Cádiz (Espagne) : les apports de la palynologie

La reconstruction temporelle des changements dans la diversité biologique est un fait potentiellement très important, autant d'un point de vue paléoécologique qu'écologique, parce que la diversité des formations végétales est, en partie, le résultat de tout un processus historique. La richesse palynologique, dans notre cas, a été estimée à partir de l'analyse de raréfaction, qui nous a permit d'étudier le site archéologique de Pocito Chico (Cádiz, Espagne). Situé dans le Parc Natural de la Baie de Cádiz, ce gisement couvre les 5000 dernières années, entre la période du Chalcolitique et le Moyen Age.Reconstructing temporal changes in diversity from pollen asemblages is potentially important both palaeoecologically and ecologically because community diversity may, in part, result from historical process. Palynological richness has been estimated by rarefaction analysis with one data set from the archaeological site of Pocito Chico (Cádiz, Spain), placed in the Natural Park of the Cádiz Bay, covering the last 5000 years from the Chalcolithic period to the Middle Age

De la tombe au territoire : les pratiques funéraires en Normandie durant l’âge du Bronze ancien et moyen

La Normandie a fait l’objet, depuis une vingtaine d’années, de nombreux programmes de recherche centrés sur l’âge du Bronze (entre 2300 et 800 avant notre ère) et abordant les notions de chronologie, d’habitat et d’emprise territoriale. Dans ces travaux résolument multiscalaires, la variable funéraire, sans être minorée, n’a jamais fait l’objet d’un travail complet et ce, malgré un fort potentiel. Les contextes funéraires de l’âge du Bronze mis au jour en Normandie se sont en effet multiplié..

Les enjeux de la régulation des entreprises de service public en France face au processus de leur libéralisation

Dans la présente contribution, les auteurs reviennent, étape par étape, sur l’impact social de la libéralisation des services d’intérêt général, au sein des entreprises concernées en France. A la lumière des transformations déjà réalisées, il s’agit de s’interroger sur le futur modèle de ces ex-entreprises publiques, qui évoluent désormais sur des marchés plus ou moins soumis à concurrence

Crisis? What crisis? : l'anthropisation du milieu et la biodiversité dans la Baie de Cádiz (Espagne) : les apports de la palynologie

La reconstruction temporelle des changements dans la diversité biologique est un fait potentiellement très important, autant d'un point de vue paléoécologique qu'écologique, parce que la diversité des formations végétales est, en partie, le résultat de tout un processus historique. La richesse palynologique, dans notre cas, a été estimée à partir de l'analyse de raréfaction, qui nous a permit d'étudier le site archéologique de Pocito Chico (Cádiz, Espagne). Situé dans le Parc Natural de la Baie de Cádiz, ce gisement couvre les 5000 dernières années, entre la période du Chalcolitique et le Moyen Age.Reconstructing temporal changes in diversity from pollen asemblages is potentially important both palaeoecologically and ecologically because community diversity may, in part, result from historical process. Palynological richness has been estimated by rarefaction analysis with one data set from the archaeological site of Pocito Chico (Cádiz, Spain), placed in the Natural Park of the Cádiz Bay, covering the last 5000 years from the Chalcolithic period to the Middle Age

Postural responses to specific types of long-term memory during visually induced roll self-motion

International audienceA large body of research has shown that visually induced self-motion (vection) and cognitive processing may interfere with each other. The aim of this study was to assess the interactive effects of a visual motion inducing vection (uniform motion in roll) versus a visual motion without vection (non-uniform motion) and long-term memory processing using the characteristics of standing posture (quiet stance). As the level of interference may be related to the nature of the cognitive tasks used, we examined the effect of visual motion on a memory task which requires a spatial process (episodic recollection) versus a memory task which does not require this process (semantic comparisons). Results confirm data of the literature showing that compensatory postural response in the same direction as background motion. Repeatedly watching visual uniform motion or increasing the cognitive load with a memory task did not decrease postural deviations. Finally, participants were differentially controlling their balance according to the memory task but this difference was significant only in the vection condition and in the plane of background motion. Increased sway regularity (decreased entropy) combined with decreased postural stability (increase variance) during vection for the episodic task would indicate an ineffective postural control. The different interference of episodic and semantic memory on posture during visual motion is consistent with the involvement of spatial processes during episodic memory recollection. It can be suggested that spatial disorientation due to visual roll motion preferentially interferes with spatial cognitive tasks, as spatial tasks can draw on resources expended to control posture

The Interaction Between Long-Term Memory and Postural Control: Different Effects of Episodic and Semantic Tasks

International audienceThe aim of this experiment was to investigate the postural response to specific types of long-term memory (episodic vs. semantic) in young adults performing an unperturbed upright stance. Although a similar level of steadiness (mean distance) was observed, dual tasking induced a higher velocity, more energy in the higher frequency range (power spectral density), and less regularity (sample entropy) compared with a simple postural task. Moreover, mean velocity was always greater in the semantic than in the episodic task. The differences in postural control during dual tasking may result from the types of processes involved in the memory task. Findings suggest a spatial process sharing between posture and episodic memory

Properties of aluminum oxide thin films deposited by pulsed laser deposition and plasma enhanced chemical vapor deposition

International audienceThe chemical, structural, mechanical and optical properties of thin aluminum oxide films deposited at room temperature (RT) and 800 °C on (100) Si and Si–SiO2 substrates by pulsed laser deposition and plasma enhanced chemical vapor deposition are investigated and compared. All films are smooth and near stoichiometric aluminum oxide. RT films are amorphous, whereas γ type nano-crystallized structures are pointed out for films deposited at 800 °C. A dielectric constant of ∼ 9 is obtained for films deposited at room temperature and 11–13 for films deposited at 800 °C. Young modulus and hardness are in the range 116–254 GPa and 6.4–28.8 GPa respectively. In both cases, the results show that the deposited films have very interesting properties opening applications in mechanical, dielectric and optical fields

Décontamination de surfaces par plasma non-thermique à l'aide d'une torche micro-ondes - évaluation du rôle complémentaire d'une couche photocatalytique de TiO2

International audienc