Estimation locale : compromis régression-variance

International audienceWe present a method allowing under some hypothesis to decrease the variance of an optimal estimator without causing damage to its risk, using many estimators jointly, thanks to a very basic technique leading to a hybrid estimator that takes advantage of the best of them. This method can be applied in various fields, typically on estimators that were obtained using linear regressions

Le foncier-environnement : pour une gestion viable des ressources naturelles renouvelables au Sahel. 1, Approche interdisciplinaire dans le delta intérieur du Niger (Mali)

Une nouvelle approche reposant sur l'étude juridique et anthropologique des différents systèmes d'exploitation du delta intérieur du Niger (Mali) et de leurs interactions permet de démontrer l'imbrication fondamentale du fonds (défini comme substrat, support des éléments biotiques) et de l'environnement (constitué des ressources renouvelables, en tant qu'enjeu de relations de pouvoirs). Cette démarche interdisciplinaire se fonde sur une approche méthodologique, prenant en compte trois échelles d'observation : le terroir villageois, la province et la région. Le but visé est de penser les principes d'un droit considérant l'ensemble des interactions qui pèsent sur le jeu des acteurs sociaux et sur la prise de décision et qui intègre la nécessité de la coviabilité à long terme de la biodiversité et de la diversité culturelle. Ce droit devrait constituer un levier de changement et permettre de passer de la situation conflictuelle et désorganisée que l'analyse des structure sociales montre, à une situation juridique où la marge de liberté des acteurs sociaux et leurs parts de responsabilité respectives sont clarifiées, en fonction des droits qu'ils ont sur les espaces-ressources et dans lesquels ils doivent être, par ailleurs, sécurisé

Patrimonialisation de la pâture

La pâture et l’activité pastorale dépendent en partie de ce que le droit en fait. Les contextes socio-écologiques dans le monde sont très variés mais il se dégage deux grands paradigmes, celui de la propriété privée et celui de la patrimonialité commune ou collective. Le rapport entre ces deux systèmes conduit soit à pérenniser l’activité pastorale, soit à la contraindre ou à l’éliminer. La marginalisation du pastoralisme n’est pas forcément rédhibitoire. De plus, le droit international parvient à classer et élever au statut de valeur universelle le paysage agro-pastoral en tant que « culture vivante ».Grazing and pastoral activities depend in part on how the law deals with them. Socio-ecological contexts are extremely varied worldwide, but generally correspond to one of two major paradigms: that of private property or that of communal or collective property. The relationship between these two systems leads either to sustaining pastoral activities, limiting them or eliminating them. The marginalization of pastoralism is not necessarily a fatality. In fact, the « territorialization » of grazing land promotes the multifunctionality of activities with environmental issues through pastoral development. Moreover, international law – by means of the Convention for the Protection of the World Cultural and Natural Heritage and the Statement of Outstanding Universal Value – has made it possible to classify the agro-pastoral landscape as a « living culture» and to raise it to the status of a universal value

Multiple scattering of an ultrasonic shock wave in bubbly media

International audienceThis experimental study deals with the propagation of an ultrasonic shock wave in a random heterogeneous medium, constituted of identical 75-µm radius bubbles, trapped in a yield-stress fluid. The fundamental frequency of the incident wave (in the MHz range) was much larger than the resonance frequency of bubbles (38 kHz). A well expanded coda, resulting from the multiple scattering of the incident shock wave through the heterogeneous medium, was experimentally measured in transmission. Despite the significant amplitude of the shock wave (90 kPa), no sign of nonlinear response of the bubbles was detected. Both the coherent and incoherent fields were successfully described by linear theories. Using a shock wave presents the advantage of characterizing the medium over a large frequency range (1.5-15 MHz)

Estimation locale : compromis régression-variance

International audienceWe present a method allowing under some hypothesis to decrease the variance of an optimal estimator without causing damage to its risk, using many estimators jointly, thanks to a very basic technique leading to a hybrid estimator that takes advantage of the best of them. This method can be applied in various fields, typically on estimators that were obtained using linear regressions

Local Holder regularity-based modeling of RR intervals

International audienceWe analyze the local regularity of RR traces from ECG through the computation of the so-called Hölder exponents. These exponents are at the basis of multifractal analysis, which has been shown to be relevant in the study of RR data. While multifractal analysis yields a global picture of the (statistical) distribution of regularity, we focus here on its time evolution. We show that this evolution is strongly correlated with the signal itself, a feature that seems to have remained unnoticed so far. We use this fact to build realistic synthetic RR traces

A robust pure hydrocarbon derivative based on the (2,1-b)-indenofluorenyl core with high triplet energy level.

International audienceA unique (2,1-b)-indenofluorenyl core flanked with two spirofluorene units, possessing a high triplet energy value and excellent thermal/morphological stability, is reported