De la décroissance démographique à la transition écologique, économique et sociale? Le cas de la ville de Dessau en Allemagne.

"Les initiatives des acteurs en présence à Dessau sont-elles en capacité d’influer sur la gestion du déclin démographique pour le transformer en processus d’autonomisation des individus, de meilleure résilience du territoire et de bien-être collectif augmenté ?"L’innovation sociale, parmi la multitude de ses acceptions actuelles, peut être comprise comme un processus résultant d’une aspiration collective à la transformation d’une situation sociale insatisfaisante ou dangereuse que ni l’Etat, ni le marché ou la croissance ne résolvent. Ce processus implique un renouvellement des modes de vie et de gouvernance porté non pas par une innovation techn(olog)ique seulement produite par des chercheurs ou des industriels, mais développée en partie par la société civile elle-même, en s’efforçant de garantir équité et justice sociale (Rousselle 2013, Richez-Battesti 2012, CSESS 2012). De ce point de vue, l’innovation sociale peut être tout aussi radicale qu’une innovation techn(olog)ique majeure, mais elle a cela de différent qu’elle prend racine dans les besoins réels et les imaginaires des citoyens. En suivant cette définition, l’on peut affirmer que la ville de Dessau en Allemagne, située dans le Land de Saxe-Anhalt, à l’est de l’Allemagne et à la confluence de l’Elbe et de la Mulde, fut un formidable laboratoire de l’innovation sociale à travers les siècles et continue de l’être actuellement. Dessau réunit les deux éléments fondamentaux de la notion de décroissance urbaine : le déclin économique et le déclin démographique. L’ex-Allemagne de l’Est a toujours constitué un lieu « privilégié » d’observation de ce phénomène, étant particulièrement durement touchée, et constitue à ce titre le second berceau de la formalisation de concept des « schrumpfende Städte », après le Middle-West des Etats-Unis et ses « shrinking cities ». Dessau, devant jouer avec des capacités humaines et financières déclinantes, constitue un laboratoire de choix pour expérimenter des solutions à ce qui demain ne sera plus le fruit de jeux économiques et démographiques régionaux, mais le résultat de l’atteinte globale des limites environnementales. Notre objectif est d’observer comment la ville, comprise comme l’ensemble de ses acteurs institutionnels, économiques, associatifs et de ses citoyens pris individuellement, fait face à l’urgence démographique de manière pratique. Notre analyse s'attache à explorer les dynamiques de gouvernance ascendantes et descendantes de la gestion de la décroissance et de ses conséquences en termes de vacance et d’engagement citoyen à Dessau

Identification of active oxalotrophic bacteria by Bromodeoxyuridine DNA labeling in a microcosm soil experiments

The oxalate-carbonate pathway (OCP) leads to a potential carbon sink in terrestrial environments. This process is linked to the activity of oxalotrophic bacteria. Although isolation and molecular characterizations are used to study oxalotrophic bacteria, these approaches do not give information on the active oxalotrophs present in soil undergoing the OCP. The aim of this study was to assess the diversity of active oxalotrophic bacteria in soil microcosms using the Bromodeoxyuridine (BrdU) DNA labeling technique. Soil was collected near an oxalogenic tree (Milicia excelsa). Different concentrations of calcium oxalate (0.5%, 1%, and 4% w/w) were added to the soil microcosms and compared with an untreated control. After 12 days of incubation, a maximal pH of 7.7 was measured for microcosms with oxalate (initial pH 6.4). At this time point, a DGGE profile of the frc gene was performed from BrdU-labeled soil DNA and unlabeled soil DNA. Actinobacteria (Streptomyces- and Kribbella-like sequences), Gammaproteobacteria and Betaproteobacteria were found as the main active oxalotrophic bacterial groups. This study highlights the relevance of Actinobacteria as members of the active bacterial community and the identification of novel uncultured oxalotrophic groups (i.e. Kribbella) active in soil

Reference-free compression of high throughput sequencing data with a probabilistic de Bruijn graph

International audienceData volumes generated by next-generation sequencing (NGS) technologies is now a major concern for both data storage and transmission. This triggered the need for more efficient methods than general purpose compression tools, such as the widely used gzip method.We present a novel reference-free method meant to compress data issued from high throughput sequencing technologies. Our approach, implemented in the software LEON, employs techniques derived from existing assembly principles. The method is based on a reference probabilistic de Bruijn Graph, built de novo from the set of reads and stored in a Bloom filter. Each read is encoded as a path in this graph, by memorizing an anchoring kmer and a list of bifurcations. The same probabilistic de Bruijn Graph is used to perform a lossy transformation of the quality scores, which allows to obtain higher compression rates without losing pertinent information for downstream analyses.LEON was run on various real sequencing datasets (whole genome, exome, RNA-seq or metagenomics). In all cases, LEON showed higher overall compression ratios than state-of-the-art compression software. On a C. elegans whole genome sequencing dataset, LEON divided the original file size by more than 20. LEON is an open source software, distributed under GNU affero GPL License, available for download at http://gatb.inria.fr/software/leon/

Phosphate Deprivation Can Impair Mechano-Stimulated Cytosolic Free Calcium Elevation in Arabidopsis Roots.

The root tip responds to mechanical stimulation with a transient increase in cytosolic free calcium as a possible second messenger. Although the root tip will grow through a heterogeneous soil nutrient supply, little is known of the consequence of nutrient deprivation for such signalling. Here, the effect of inorganic phosphate deprivation on the root's mechano-stimulated cytosolic free calcium increase is investigated. Arabidopsisthaliana (cytosolically expressing aequorin as a bioluminescent free calcium reporter) is grown in zero or full phosphate conditions, then roots or root tips are mechanically stimulated. Plants also are grown vertically on a solid medium so their root skewing angle (deviation from vertical) can be determined as an output of mechanical stimulation. Phosphate starvation results in significantly impaired cytosolic free calcium elevation in both root tips and whole excised roots. Phosphate-starved roots sustain a significantly lower root skewing angle than phosphate-replete roots. These results suggest that phosphate starvation causes a dampening of the root mechano-signalling system that could have consequences for growth in hardened, compacted soils

Plasmonic mode interferences and Fano resonances in Metal-Insulator-Metal nanostructured interface OPEN

International audienceMetal-insulator-metal systems exhibit a rich underlying physics leading to a high degree of tunability of their spectral properties. We performed a systematic study on a metal-insulator-nanostructured metal system with a thin 6 nm dielectric spacer and showed how the nanoparticle sizes and excitation conditions lead to the tunability and coupling/decoupling of localized and delocalized plasmonic modes. We also experimentally evidenced a tunable Fano resonance in a broad spectral window 600 to 800 nm resulting from the interference of gap modes with white light broad band transmitted waves at the interface playing the role of the continuum. By varying the incident illumination angle shifts in the resonances give the possibility to couple or decouple the localized and delocalized modes and to induce a strong change of the asymmetric Fano profile. All these results were confirmed with a crossed comparison between experimental and theoretical measurements, confirming the nature of different modes. The high degree of control and tunability of this plasmonically rich system paves the way for designing and engineering of similar systems with numerous applications. In particular, sensing measurements were performed and a figure of merit of 3.8 was recorded ranking this sensor among the highest sensitive in this wavelength range. Surface plasmon polariton (SPP) and Localized surface plasmon (LSP) have attracted numerous researchers due to their high technological potential. SPP's are surface waves confined near a metal dielectric interface that can propagate over large distances 1 , making them appealing for applications in biosens-ing 2,3. On the other hand LSP resonances can be defined as the localized resonance condition that massively enhances the electromagnetic field in the vicinity of a metal nanoparticle (NP), when the NP have dimensions much smaller than the excitation wavelength 4. LSP resonance is very sensitive to changes in the NP's dimensions, the dielectric constant of the surrounding media and the nature of the substrate. Because of intense local electrical field enhancements and sharp resonance excitation peaks, metallic NPs are of great interest for applications in surface enhanced Raman spectroscopy (SERS) 5 , chemical and biological sensors 3,6 , cancer treatment 7 and light harvesting 8–10. Recently, strong attention was paid to the potentials of SPP and LSP combinations by investigating metallic NPs on top of metallic thin films. Several studies on such systems have indeed shown the coupling and hybridization between localized and delocalized modes, and the effect of the thickness of the dielectric spacer. Those works have revealed that such coupled systems exhibit enhanced optical properties and larger tunability of their spectral properties compared to uncoupled systems 1,4,11–2