Segmentation en régions non supervisée par relaxation markovienne, une étude comparative

Nous présentons un algorithme de segmentation en régions non supervisé qui utilise la théorie des champs de Markov. Ces techniques de relaxation markoviennes amènent à de bons résultats mais présentent cependant les inconvénients, dans leur implantation classique, de conduire à des temps de calcul élevés et de nécessiter l'introduction de plusieurs seuils. Nous nous sommes donc proposé de résoudre ces deux problèmes majeurs et avons développé une nouvelle technique de relaxation markovienne. Une étude comparative des différentes stratégies d'utilisation des relaxations markoviennes est ensuite menée, de manière rigoureuse, aussi bien du point de vue qualité des résultats que du point de vue coût algorithmique. Des conclusions intéressantes en découlent

Effect of human vicinity on antimicrobial resistance and integrons in animal faecal Escherichia coli”.

Objectives: To determine the level of antimicrobial resistance and the occurrence of class 1, 2 and 3 integrons in faecal Escherichia coli from several animal populations variously exposed to human contact. Methods: A collection of 341 faecal E. coli isolates was constituted from several animal populations subject to various degrees of exposure to humans: 18 animals never exposed to humans (living in the Antarctic or Gabon), 71 wild animals living in a low human density area (mountainous region of the Pyrenees, France), 61 wild animals living in a higher human density area (Fontainebleau forest near Paris, France), and 128 extensively reared farm animals and 42 pet dogs, both living in the Pyrenees. Resistance to antimicrobial agents was determined by the method of disc diffusion and quantified using the resistance score of BE Murray, JJ Mathewson, HL DuPont, CD Ericsson and RR Reves (Antimicrobial Agents and Chemotherapy 1990; 34: 515-18). Integrons were characterized by triplex realtime PCR and sequencing. The absence of epidemiologic clones was confirmed by PCR-based methods. Results: A gradient of resistance ranging from absence to high prevalence (resistance score of 18.7%) and a gradual increase in the prevalence of class 1 integrons (from 0% to 16%), both correlated with the increase in exposure to humans, were observed. In wild animals with little contact with humans, resistance, when present, was not mediated by integrons. Conclusions: Our findings firmly establish that the current prevalence of antimicrobial resistance found in animal faecal bacteria, as well as the prevalence of integrons, is clearly anthropogenic. The presence of integrons may constitute an adaptive process to environments whose antimicrobial pressure exceeds a certain threshold

Agglomeration of stoichiometric hydroxyapatite: Impact on particle size distribution and purity in the precipitation and maturation steps

Stoichiometric hydroxyapatite (HAP) is a prominent biomaterial, notably used as coating on metal bone prostheses. High chemical purity and a specific particle size distribution are the main properties for such an application. Based on industrial practice, a reference synthesis was first performed in a lab-scale stirred reactor. Improvements were then suggested by varying the physicochemical and hydrodynamic conditions. The shear rate within the reactor, characterized by the mean Kolmogorov micro-scale, has a strong impact on the final agglomerate size distribution. By maintaining a rather high mixing rate and a high temperature, the duration of the synthesis can be reduced considerably without affecting the HAP purity provided the pH is properly regulated. This consists of imposing acidic conditions during a short period just after the initial formation of large aggregates and then setting the pH at above 7.5 to ensure the production of pure stoichiometric HAP

Wild Animal Mortality Monitoring and Human Ebola Outbreaks, Gabon and Republic of Congo, 2001–2003

An animal mortality monitoring network in Gabon and the Republic of Congo has demonstrated potential to predict and possibly prevent human Ebola outbreaks

Produire des contenus documentaires en ligne

Les bibliothèques sont confrontées à des nécessités d’exploitation de leurs collections qui ne passent plus seulement par la gestion du stock mais par l’appropriation et la restitution de contenus documentaires. Le plan de l’ouvrage s’articule autour de quatre parties : exploiter les collections ; la curation et la production de contenus ; produire en réseau, et enfin, connaître le contexte juridique et écrire pour le web. Ainsi, le professionnel est devenu médiateur, producteur et éditeur de matières documentaires élaborées. Chaque partie traite aussi des nouvelles compétences relationnelles et techniques à acquérir pour ce faire. Une quinzaine de professionnels abordent ces différents aspects, en s’appuyant sur des réalisations concrètes menées dans les bibliothèques, de lecture publique comme des universités

Cross-Dehydrogenative Couplings between Indoles and β-Keto Esters : Ligand-Assisted Ligand Tautomerization and Dehydrogenation via a Proton-Assisted Electron Transfer to Pd(II)

Cross-dehydrogenative coupling reactions between -ketoesters and electron-rich arenes, such as indoles, proceed with high regiochemical fidelity with a range of -ketoesters and indoles. The mechanism of the reaction between a prototypical -ketoester, ethyl 2-oxocyclopentanonecarboxylate and N-methylindole, has been studied experimentally by monitoring the temporal course of the reaction by 1H NMR, kinetic isotope effect studies, and control experiments. DFT calculations have been carried out using a dispersion-corrected range-separated hybrid functional (B97X-D) to explore the basic elementary steps of the catalytic cycle. The experimental results indicate that the reaction proceeds via two catalytic cycles. Cycle A, the dehydrogenation cycle, produces an enone intermediate. The dehydrogenation is assisted by N-methylindole, which acts as a ligand for Pd(II). The compu-tational studies agree with this conclusion, and identify the turnover-limiting step of the dehydrogenation step, which involves a change in the coordination mode of the -keto ester ligand from an O,O’-chelate to an C-bound Pd enolate. This ligand tautom-erization event is assisted by the -bound indole ligand. Subsequent scission of the ’-C–H bond takes place via a proton-assisted electron transfer mechanism, where Pd(II) acts as an electron sink and the trifluoroacetate ligand acts as a proton acceptor, to pro-duce the Pd(0) complex of the enone intermediate. The coupling is completed in cycle B, where the enone is coupled with indole. Pd(TFA)2 and TFA-catalyzed pathways were examined experimentally and computationally for this cycle, and both were found to be viable routes for the coupling step

Etude des facteurs modifiant la pénétrance clinique et biologique de l'hémochromatose génétique homozygote C282Y chez 50 patients appartenant à 19 familles habitant en Midi-Pyrénées

La pénétrance clinique et biologique de l'hémochromatose homozygote C282Y est très variable. Nous avons étudié 50 patients appartenant à 19 familles habitant en Midi-Pyrénées afin de confirmer les données de la littérature. La pénétrance clinique de l'hémochromatose dans notre région est plus élevée notamment pour les arthralgies. La pénétrance biologique est également élevée. Cette étude confirme partiellement les données connues sur les facteurs susceptibles de modifier la pénétrance clinique et biologique (cas index, sexe masculin, alcool). Biologiquement seul l'homogénéité intrafamiliale de la ferritine évoque la présence de gènes modificateurs sur le modèle humain.TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

La lagune de La Palme (Aude, France) face au comblement et à l'eutrophisation

L'article montre le fonctionnement et l'évolution spatiale et temporelle de la lagune de La Palme (Aude, France). Les aménagements ont réduit la surface en eau, perturbé les échanges hydriques, favorisé la sédimentation et fait apparaître des phénomènes d'eutrophisation. Des mesures GPS sur une dizaine d'années révèlent la forte mobilité du grau de La Franqui, mais une relative stabilité du trait de côte à proximité de ce dernier.The paper aims at achieving a better understanding of the La Palme lagoon functioning and its evolution in time and space. Anthropogenic infrastructures and activities have reduced the water area, disrupted water exchanges, promoted sedimentation and revealed a tendency to eutrophication. GPS measurements over several years show high mobility of the La Franqui inlet and relative shoreline stability near the inlet

A 3-D genetic approach to high-resolution geological modelling of the volcanic infill of a paleovalley system. Application to the Volvic catchment (Chaîne des Puys, France)

International audienceThe Volvic natural mineral water is catched in a complex volcanic aquifer located in the northern part of the "Chaine des Puys" volcanic system (Auvergne, France). In the watershed, water transits through scoria cones and basaltic to trachybasaltic lava flows. These aa lava flows, emitted by strombolian cones between 75,000 and 10,000 years ago, are emplaced in deep paleovalleys incised within the variscan crystalline bedrock. The volcanic infill is highly heterogeneous. In order to build a hydrogeological model of the watershed, a simple but robust methodology was developed to reconstruct the bedrock morphology and the volcanic infill in this paleovalley context. This methodology, based on the combination of genetic and geometric approaches, appears to be rather efficient to define both the substratum and the lava flows geometry. A 3D geological model is then proposed. It synthesizes the data from 99 boreholes logs, 2D geoelectric profiles, morphologic clues, datings and petrographic data. A genetic approach, integrating aa lava flow morphology and emplacement behaviour, was used to reconstruct the chronology of the volcanic events and lava flow emplacement from the upper part of the Domes plateau to the Limagne plain. The precision of the volcanic reconstruction is discussed: the main limitation of the methodology are related to the homogeneity of the petrographic and geochemical composition of the lava flows succession (except for the trachyandesitic Nugere lava), the spatially variable borehole density, the lack of a real petrographical and geological description on most of the available geological logs. Nevertheless, the developed methodology combining spatial and genetic approaches appears to be well adapted to constrain complex lava flow infill geometries in paleovalley context

Automated measurement of pollens rates by computer vision

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