Apprentissage collectif pour décider de l'avenir du territoire de Thau : premiers retours d'une approche combinant politique publique et participation

Les politiques publiques en France pour l'aménagement du territoire à un niveau local tendent vers des approches de plus en plus transversales, guidées par le principe du développement durable, et débouchant sur des « projets de territoire ». De plus, la loi impose une participation croissante des acteurs concernés et plus largement de la société civile. Ce contexte remet en cause, du moins dans les discours, le modèle de décision dominant basé sur la démocratie représentative au profit d'une gouvernance participative. « Développement durable » et « participation » font désormais partie des mots-clés incontournables de tout nouveau projet de territoire. En pratique, ces injonctions de démocratie participative génèrent selon les acteurs toute une gamme de réactions allant de l'enthousiasme sincère au rejet d'un tel changement en passant par la curiosité, l'incrédulité, la récupération politique ou des stratégies opportunistes. Les finalités de la participation sont également multiples selon les cas et pas toujours bien explicités et donc bien partagés par les participants. Dans la plupart des cas, au delà des stratégies cyniques de participation de façade, la finalité reste du domaine de l'innovation en management de projet comme en témoignent les objectifs cités dans les nombreux guides méthodologiques récents sur la participation. Il s'agit alors de profiter des savoirs locaux pour affiner le diagnostic, d'associer les acteurs et les citoyens de différentes manières à la réflexion pour renforcer leur acceptation des décisions et des plans d'actions. Mais globalement, le processus de prise de décision et la distribution des pouvoirs restent les mêmes. Une autre finalité, beaucoup plus ambitieuse et idéaliste, est de lutter contre une forme généralisée d'indifférence citoyenne vis à vis de l'aménagement local du territoire et d'arriver à retisser des liens de confiance entre pouvoir politique et société civile. Les deux finalités ne sont pas forcément incompatibles, la seconde pouvant se nourrir de la première par apprentissage progressif et cumulatif à partir d'expériences participatives de projets de développement local sur un même territoire. L'importance d'une entrée informationnelle et communicationnelle pour étudier les processus d'aménagement et de développement territorial avait déjà été soulignée par la DATAR en 1998 : « Le développement territorial est une organisation à construire par de l'information en reliant des acteurs publics et privés, engagés dans une dynamique de projet sur un territoire». Cette entrée a ensuite été théorisée par des chercheurs en sciences de l'information et de la communication qui ont développé le concept « d'intelligence territoriale ». Bertacchini (2004) en donne la définition suivante : « On peut considérer l'intelligence territoriale comme un processus informationnel et anthropologique, régulier et continu, initié par des acteurs locaux physiquement présents et/ou distants qui s'approprient les ressources d'un espace en mobilisant puis en transformant l'énergie du système territorial en capacité de projet ». L'objectif de notre article est d'étudier du point de vue informationnel et communicationnel comment des processus participatifs de planification territoriale peuvent contribuer à élever le degré d'intelligence territoriale d'un territoire donné, et donc in fine, à faire évoluer l'ensemble du processus de décision territoriale. Nous nous concentrerons pour le moment sur des micro-évènements d'un processus participatif à plus long terme pour la planification d'un territoire côtier. Après avoir présenté dans une première partie la méthodologie employée et notre cadre théorique d'analyse, nous décrirons dans un deuxième temps les dimensions physique, institutionnelle et sociétale du territoire étudié. Puis nous aborderons dans une troisième partie la genèse et l'organisation du processus participatif mis en place sur ce territoire. Nous présenterons alors différents outils d'information et de communication mobilisés dans certaines étapes du processus en détaillant leurs usages et leurs effets. Nous conclurons alors cet article en tirant les premières leçons de cette expérience et en présentant les recherches programmées sur ce territoire pour les trois années à venir

Meteorite cloudy zone formation as a quantitative indicator of paleomagnetic field intensities and cooling rates on planetesimals

Metallic microstructures in slowly-cooled iron-rich meteorites reflect the thermal and magnetic histories of their parent planetesimals. Of particular interest is the cloudy zone, a nanoscale intergrowth of Ni-rich islands within a Ni-poor matrix that forms below 350{\deg}C by spinodal decomposition. The sizes of the islands have long been recognized as reflecting the low-temperature cooling rates of meteorite parent bodies. However, a model capable of providing quantitative cooling rate estimates from island sizes has been lacking. Moreover, these islands are also capable of preserving a record of the ambient magnetic field as they grew, but some of the key physical parameters required for recovering reliable paleointensity estimates from magnetic measurements of these islands have been poorly constrained. To address both of these issues, we present a numerical model of the structural and compositional evolution of the cloudy zone as a function of cooling rate and local composition. Our model produces island sizes that are consistent with present-day measured sizes. This model enables a substantial improvement in the calibration of paleointensity estimates and associated uncertainties. In particular, we can now accurately quantify the statistical uncertainty associated with the finite number of islands and the uncertainty on their size at the time of the record. We use this new understanding to revisit paleointensities from previous pioneering paleomagnetic studies of cloudy zones. We show that these could have been overestimated but nevertheless still require substantial magnetic fields to have been present on their parent bodies. Our model also allows us to estimate absolute cooling rates for meteorites that cooled slower than 10000{\deg}C My-1. We demonstrate how these cooling rate estimates can uniquely constrain the low-temperature thermal history of meteorite parent bodies.Comment: Manuscript resubmitted after revision

Fourier analysis of wave turbulence in a thin elastic plate

The spatio-temporal dynamics of the deformation of a vibrated plate is measured by a high speed Fourier transform profilometry technique. The space-time Fourier spectrum is analyzed. It displays a behavior consistent with the premises of the Weak Turbulence theory. A isotropic continuous spectrum of waves is excited with a non linear dispersion relation slightly shifted from the linear dispersion relation. The spectral width of the dispersion relation is also measured. The non linearity of this system is weak as expected from the theory. Finite size effects are discussed. Despite a qualitative agreement with the theory, a quantitative mismatch is observed which origin may be due to the dissipation that ultimately absorbs the energy flux of the Kolmogorov-Zakharov casade.Comment: accepted for publication in European Physical Journal B see http://www.epj.or

Quand l'information échappe à ses créateurs : le cas de l'artificialisation des terres agricoles en Languedoc-Roussillon

International audienceThis article aims to describe how the quantification of a phenomenon in relation to a specific worldview spreads and is distorted. This project has been supported by a regional public authority in Languedoc-Roussillon (France), and consisted in the production of information so to quantify and qualify the farmland decrease due to urban sprawl. The paper is based on Latour's actor-network theory; it characterizes the process of enrolment, and the development of dissidences. Identifying contradictory logics and dissidences help questioning the complexity of ‘closing the black-box' regarding information production and of sensemaking between heterogeneous actants involved in a supposed-to-be public debate.Cet article vise à spécifier comment la quantification d'un phénomène fondée sur une certaine vision du monde se propage et se déforme. Ce projet a été porté par une direction déconcentrée de l'Etat soucieuse de l'emprise croissante du bâti sur les terres agricoles en Languedoc-Roussillon. Le cadre théorique mobilisé, la sociologie de la traduction, permet d'identifier les grandes étapes d'intéressement, d'enrôlement, ainsi que le développement de controverses. Les difficultés rencontrées interrogent sur la complexité de clôture de processus innovants s'agissant de production d'information et de co-construction de sens associant des actants hétérogènes impliqués dans des procédures de débat public

Reading ecosystem services at the local scale through a territorial approach: The case of peri-urban agriculture in the thau Lagoon, Southern France

© 2015 by the author(s). In recent years, the ecosystem services (ES) concept has become a major paradigm for natural resource management. While policy-makers demand “hard” monetary evidence that nature conservation would be worth investing in, ongoing attempts are being made to formalize the concept as a scientifically robust “one size fits all” analytical framework. These attempts have highlighted several major limitations of the ES concept. First, to date, the concept has paid little attention to the role of humans in the production of ES. Second, the ongoing formalization of the ES concept is turning it into a “technology of globalization,” thereby increasingly ignoring the socio-cultural context and history within which ecosystems emerge. Third, economic valuation has been shown to limit local stakeholders in expressing their daily and immediate ways of interacting with their environment over and beyond extrinsic motivation provided by financial gains. We address these three limitations by analyzing a social evaluation of the roles of peri-urban farmland from a territorial perspective. Our case study is the Thau lagoon in southern France. We conducted in-depth interviews with a broad range of stakeholders and ran two participatory workshops. Using a territorial meta-model that distinguishes three levels— physical, logical, and existential—stakeholder data were analyzed to unravel the interplay of territorial elements at these three levels that gives rise to ES in two broad categories: food production and aesthetic landscape. The coupling of ES and territory concepts opens up several novel analytical perspectives. It allows partitioning of ES in a manner that “re-contextualizes” them and gives insight about both their physical constituents and their meaning at the territorial level. Additional research should incorporate the dynamics of service demand and supply, and further investigate options for implementation

Meteorite cloudy zone formation as a quantitative indicator of paleomagnetic field intensities and cooling rates on planetesimals

Metallic microstructures in slowly-cooled iron-rich meteorites reflect the thermal and magnetic histories of their parent planetesimals. Of particular interest is the cloudy zone, a nanoscale intergrowth of Ni-rich islands within a Ni-poor matrix that forms below ∼350 °C by spinodal decomposition. The sizes of the islands have long been recognized as reflecting the low-temperature cooling rates of meteorite parent bodies. However, a model capable of providing quantitative cooling rate estimates from island sizes has been lacking. Moreover, these islands are also capable of preserving a record of the ambient magnetic field as they grew, but some of the key physical parameters required for recovering reliable paleointensity estimates from magnetic measurements of these islands have been poorly constrained. To address both of these issues, we present a numerical model of the structural and compositional evolution of the cloudy zone as a function of cooling rate and local composition. Our model produces island sizes that are consistent with present-day measured sizes. This model enables a substantial improvement in the calibration of paleointensity estimates and associated uncertainties. In particular, we can now accurately quantify the statistical uncertainty associated with the finite number of islands acquiring the magnetization and the uncertainty on their size at the time of the record. We use this new understanding to revisit paleointensities from previous pioneering paleomagnetic studies of cloudy zones. We show that these could have been overestimated by up to one order of magnitude but nevertheless still require substantial magnetic fields to have been present on their parent bodies. Our model also allows us to estimate absolute cooling rates for meteorites that cooled slower than <10,000 °C My−1. We demonstrate how these cooling rate estimates can uniquely constrain the low-temperature thermal history of meteorite parent bodies. Using the main-group pallasites as an example, we show that our results are consistent with the previously-proposed unperturbed, conductive cooling at low temperature of a ∼200-km radius main-group pallasite parent body

Effect of nearest neighbor repulsion on the low frequency phase diagram of a quarter-filled Hubbard-Holstein chain

We have studied the influence of nearest-neighbor (NN) repulsion on the low frequency phase diagram of a quarter-filled Hubbard-Holstein chain. The NN repulsion term induces the apparition of two new long range ordered phases (one $4k_F$ CDW for positive $U_{eff} = U-2g^2/\omega$ and one $2k_F$ CDW for negative $U_{eff}$) that did not exist in the V=0 phase diagram. These results are put into perspective with the newly observed charge ordered phases in organic conductors and an interpretation of their origin in terms of electron-molecular vibration coupling is suggested.Comment: 10 pages, 10 figure

ExTrA: Exoplanets in Transit and their Atmospheres

The ExTrA facility, located at La Silla observatory, will consist of a near-infrared multi-object spectrograph fed by three 60-cm telescopes. ExTrA will add the spectroscopic resolution to the traditional differential photometry method. This shall enable the fine correction of color-dependent systematics that would otherwise hinder ground-based observations. With both this novel method and an infrared-enabled efficiency, ExTrA aims to find transiting telluric planets orbiting in the habitable zone of bright nearby M dwarfs. It shall have the versatility to do so by running its own independent survey and also by concurrently following-up on the space candidates unveiled by K2 and TESS. The exoplanets detected by ExTrA will be amenable to atmospheric characterisation with VLTs, JWST, and ELTs and could give our first peek into an exo-life laboratory.Comment: 15 pages, 11 figures, SPIE 201

Creep stability of the proposed AIDA mission target 65803 Didymos: I. Discrete cohesionless granular physics model

As the target of the proposed Asteroid Impact & Deflection Assessment (AIDA) mission, the near-Earth binary asteroid 65803 Didymos represents a special class of binary asteroids, those whose primaries are at risk of rotational disruption. To gain a better understanding of these binary systems and to support the AIDA mission, this paper investigates the creep stability of the Didymos primary by representing it as a cohesionless self-gravitating granular aggregate subject to rotational acceleration. To achieve this goal, a soft-sphere discrete element model (SSDEM) capable of simulating granular systems in quasi-static states is implemented and a quasi-static spin-up procedure is carried out. We devise three critical spin limits for the simulated aggregates to indicate their critical states triggered by reshaping and surface shedding, internal structural deformation, and shear failure, respectively. The failure condition and mode, and shear strength of an aggregate can all be inferred from the three critical spin limits. The effects of arrangement and size distribution of constituent particles, bulk density, spin-up path, and interparticle friction are numerically explored. The results show that the shear strength of a spinning self-gravitating aggregate depends strongly on both its internal configuration and material parameters, while its failure mode and mechanism are mainly affected by its internal configuration. Additionally, this study provides some constraints on the possible physical properties of the Didymos primary based on observational data and proposes a plausible formation mechanism for this binary system. With a bulk density consistent with observational uncertainty and close to the maximum density allowed for the asteroid, the Didymos primary in certain configurations can remain geo-statically stable without including cohesion.Comment: 66 pages, 24 figures, submitted to Icarus on 25/Aug/201