Éditeur(s) : HAL CCSD SciTePress
Résumé : International audience
Data integration and knowledge capitalization combine data and information coming from different data sources designed by different experts having different purposes. In this paper, we propose to assist the underlying model merging activity. For close models made by experts of various specialities, we partially automate the identification of a Greatest Common Model (GCM) which is composed of the common concepts (core concepts) of the different models. Our methodology is based on Formal Concept Analysis which is a method of data analysis based on lattice theory. A decision tree allows to semi-automatically classify concepts from the concept lattices and assist the GCM extraction. We apply our approach on the EIS-Pesticide project, an environmental information system which aims at centralizing knowledge and information produced by different specialized teams.
ICEIS 2012: 14th International Conference on Enterprise Information Systems
Wroclaw, Poland

lirmm-00727009
https://hal-lirmm.ccsd.cnrs.fr/lirmm-00727009

Éditeur(s) : HAL CCSD
Résumé :   Diplôme : DEA
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
En forêt tropicale humide les espèces arborées ont des stratégies différentes d'acquisition de l'azote : les espèces fixatrices utilisent l'azote atmosphérique N2 de l'air. Il existe des espèces à préférence à ammonium (NH+) ou à nitrate (NO3-), mais aussi des espèces ubiquistes se nourrissant des deux sources d'azote du sol. L'objectif de ce travail était de déterminer si ces stratégies différentes étaient intrinsèques à l'espèce ou si elles étaient conditionnées par le milieu du fait des compétitions intra et/ou interspécifiques. Nous avons étudié la nutrition azotée d'une vingtaine d'espèces d'arbres juvéniles élevés en pot sur sol de forêt en conditions semi-contrôlées (20% d'éclairement). Deux méthodes ont été utilisées : la mesure de l'activité nitrate réductase in vivo après induction par pulvérisation de nitrate sur les feuilles et la signature isotopique naturelle δ15N. Les résultats obtenus ont montré que la majorité des plantes en serre sembleraient capable d'utiliser l'une ou l'autre des deux sources avec une forte plasticité vis-à-vis de l'azote. Quelques espèces cependant n'utiliseraient que l'ammonium comme source d'azote malgré le milieu limitant, bien qu'ayant une activité nitrate reductase potentielle, traduisant une capacité non exploitée à assimiler le nitrate, les plantes fixatrices, elles, sembleraient avoir accès aux deux sources d'azote du sol. En utilisant des traits d'héliophile peu de liens ont été observés avec le tempérament des espèces vis-à-vis de la lumière. Des mesures complémentaires sous différents éclairements (5, 10 et 30%) seraient nécessaires pour conclure sur ce sujet. Les différences de nutrition observées dans le milieu naturel seraient dues aux conditions du milieu même si indirectement il se pourrait que la plante ait le pouvoir d'influencer le choix de la source en inhibant la nitrification au niveau rhizosphérique par le biais d'exsudats racinaires.
https://hal.archives-ouvertes.fr/hal-01189235

hal-01189235
https://hal.archives-ouvertes.fr/hal-01189235
PRODINRA : 17890

Éditeur(s) : HAL CCSD Elsevier
Résumé : Volatile terpenes are among the most diverse class of defensive compounds in plants, and they are implicated in both direct and indirect defense against herbivores. In terpenes, both the quantity and the diversity of compounds appear to increase the efficiency of defense as a diverse blend of compounds provides a more efficient protection against a broader range of herbivores and limits the chances that an enemy evolves resistance. Theory predicts that plant defensive compounds should be allocated differentially among tissues according to the value of the tissue, its cost of construction and the herbivore pressure on it. We collected volatile terpenes from bark and leaves of 178 individual tree belonging to 55 angiosperm species in French Guiana and compare the kind, amount, and diversity of compounds in these tissues. We hypothesized that in woody plants, the outermost part of the trunk should hold a more diverse blend of volatile terpenes. Additionally, as herbivore communities associated with the leaves is different to the one associated with the bark, we also hypothesized that terpene blends should be distinct in the bark vs. the leaves of a given species. We found that the mixture of volatile terpenes released by bark is different and more diverse than that released by leaves, both in monoterpenes and sesquiterpenes. This supports our hypothesis and further suggests that the emission of terpenes by the bark should be more important for trunk defense than previously thought. (c) 2012 Elsevier Ltd. All rights reserved.
ISSN: 0031-9422

hal-01032417
https://hal.archives-ouvertes.fr/hal-01032417
DOI : 10.1016/j.phytochem.2012.07.003

Éditeur(s) : HAL CCSD
Résumé : For ecology scientists, spatial statistics are a set of tools allowing characterization of the structure of a point set, for instance a map of trees in a forest plot. This structure is defined implicitly as a departure from complete spatial randomness (CSR), the result of a Poisson point process. Inhomogeneity of the process and non-independence of points are its causes. As they cannot be disentangled by analyzing the data, so-called "spatial concentration" or "aggregation" (evenness due to repulsion also exists but is actually rare) usually concerns non-independence while intensity is assumed as known. The literature of point processes and measures of spatial structures is reviewed to clarify concepts and choices. The purpose of this thesis was to produce methodological enhancements. Its main results are: * A test for the most used statistic, Ripley's K function, against the null hypothesis of CSR. It can replace Monte-Carlo simulations used until now in the literature. * An extension of K to inhomogeneous processes, within a typology of available statistics (absolute, relative and topographic measures). When data is available as number of objects per zones (say a number of tree in each forest plot) rather than their exact position, information theory is used to define a general framework allowing to characterize spatial structure (of species) and diversity (of plots) as two aspects of a single measure of inequality. This framework is applied to Shannon's index of biodiversity to derive a self-sufficient definition of beta diversity, its calculation independently from the difference between gamma and alpha diversity, and a statistical test of significance against the null hypothesis that plots are samples of the same community. The way is paved for other applications to measures of diversity and spatial structures. As a conclusion, it appears clear that pattern characterization tools are a first step to deal with ecological questionings. Their development is still a matter of research. Yet, they are far from sufficient to address ecological processes as point processes ignore the temporal aspect of object locations.
Les statistiques spatiales sont pour les écologues un ensemble d'outils permettant de caractériser la structure d'un semis de points, par exemple une carte représentant des emplacements des arbres dans une parcelle de forêt. Cette structure est définie implicitement comme un écart à semis complètement aléatoire, résultat d'un processus de Poisson. L'hétérogénéité du processus ponctuel dont le semis de points est une réalisation et la non-indépendance des points en sont les causes indiscernables, ce qui amène généralement à supposer l'intensité du processus connu et nommer " concentration spatiale " ou " agrégation " (la régularité spatiale est possible, mais rare en pratique) la non-indépendance. Une revue de la littérature des processus ponctuels et des mesures de structures spatiales est fournie pour clarifier les concepts et les choix. L'objectif de ce travail de thèse était de produire des améliorations méthodologiques. Ses résultats principaux sont : * L'établissement d'un test pour la principale statistique utilisée, la fonction K de Ripley, permettant de s'affranchir de la méthode de Monte-Carlo utilisée dans la littérature pour rejeter l'hypothèse nulle d'un processus complètement aléatoire. * L'extension de K aux processus hétérogènes, dans le cadre d'une typologie claire des statistiques (absolues, relatives, topographiques). Lorsque la position exacte des objets n'est pas connue, mais que des effectifs par zone sont disponibles (par exemple des nombres d'arbres par parcelle), la théorie de l'information est utilisée pour définir un cadre général permettant de caractériser la structure spatiale (des espèces dans les parcelles) et la diversité (des parcelles, en termes d'espèces) comme deux aspects d'une même mesure d'inégalité. Ce cadre est appliqué à l'indice de biodiversité de Shannon pour définir clairement la mesure de diversité bêta, son calcul direct indépendamment de la différence entre diversités gamma et alpha, et fournir un test statistique de non nullité. La voie est ouverte pour l'application à d'autres mesures de diversité et de structure spatiale. En conclusion, il semble clair que ces outils de caractérisation sont un premier pas pour traiter les questions écologiques, leur développement étant toujours du domaine de la recherche. Ils sont cependant très insuffisants pour répondre à des questions liées aux processus écologiques, assez éloignés des processus ponctuels qui ignorent l'aspect temporel de l'installation des objets.
https://pastel.archives-ouvertes.fr/pastel-00540327

NNT : 2010AGPT0075
pastel-00540327
https://pastel.archives-ouvertes.fr/pastel-00540327
https://pastel.archives-ouvertes.fr/pastel-00540327/document
https://pastel.archives-ouvertes.fr/pastel-00540327/file/13_Marcon2010.pdf

Éditeur(s) : HAL CCSD Springer-Verlag Berlin Heidelberg
Résumé : International audience
Reaction wood produces very peculiar maturation stresses at the tree periphery i.e. compressive stress or very high tensile stress, for compression and tension wood respectively, as compared to moderately high tensile stress for normal wood. This means that both its mechanical state and its mechanical and physical properties differ from normal wood. Compression wood shows big differences from normal wood in conifers, for all physical and mechanical properties: higher density and axial crushing strength (MOR) but lower modulus of elasticity (MOE), far higher axial (longitudinal) shrinkage but lower radial and tangential shrinkage, sometimes even lower than the axial shrinkage. For tension wood things are less simple and can vary a lot from hardwood species to species. Globally there are no systematic differences in density and transverse shrinkage, MOE tends to be a little higher while MOR is slightly lower. However, axial shrinkage is much higher for tension wood with a gelatinous layer (G layer) than normal wood due to the specific gel like organization of cellulose microfibrils in the G layer. For tension wood without a G layer(which is rather frequent) axial shrinkage in the first drying operation is around two times higher than in normal wood mainly because of a kind of hygro-thermal release of locked in maturation stress. Overall the very high tensile stress and stored elastic energy in tension wood lead to problemsin wood processing (end splitting and board warping), which is far less the case for compression wood. But due to the large difference in properties relative to normal wood, compression wood occurrence is always a big problem for the in service behaviour of timber, which is seldom the case for tension wood.
The biology of reaction wood

ISBN : 978-3-642-10813-6
hal-01135273
https://hal.archives-ouvertes.fr/hal-01135273

Résumé : Aujourd’hui, il est indispensable de découvrir de nouveaux agents thérapeutiques pour faire face à l’expansion des infections fongiques humaines. D’un autre côté, certains arbres amazoniens ont acquis des moyens pour se protéger contre la dégradation fongique. Ces composés d’origine végétale pourraient donc être des candidats potentiels au développement de composés antifongiques. Il est ainsi exposé dans ce travail la sélection bio-inspirée et la récolte d’espèces d’arbres amazoniens résistants à la dégradation fongique ; à partir desquelles il est proposé d’isoler, d’identifier et de valoriser les métabolites responsables de la durabilité naturelle et d’étudier leurs propriétés sur des champignons pathogènes humains. Cette étude a conduit à l’isolement de molécules inédites apportant un complément d’information chimiotaxonomique pour les espèces étudiées. De plus, il a pu être mis en avant deux molécules pouvant devenir des composés pertinents pour le développement de traitements antimycotiques.
It is now essential to discover new therapeutic agents against the increase of human fungal infections. On the other hand, some Amazonian trees have succeeded to develop a chemical defense arsenal to protect themselves against fungal degradation. These compounds of plant origin could become potential candidates for the development of antifungal compounds for the treatment of human fungal diseases. Therefore, this manuscript describes the bio-inspired selection and collection of Amazonian tree species capable of specializing a highly fungiresistant wood; from which it is proposed to isolate, identify and valorize the secondary metabolites responsible for the natural durability, and study their properties on human pathogenic fungi. Ultimately, this study led to the isolation of new compounds and providing additional important chemotaxonomic information for the species studied. In addition, it as been established that two compounds could be relevant for the development of antimitotic therapies.

http://www.theses.fr/2011AGUY0467/document

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
After noting the forecast of a La Niña episode, associated with heavy rainfall in French Guiana, we monitored the fate of wasp nests before and during the 2006 short rainy season. The population of the most abundant epiponine wasp species, Polybia bistriata, decreased dramatically during the short rainy season (60.6% of the nests disappeared) then remained low for at least 18 months. Colonies that survived moved from the shelter of large, low leaves (a situation well adapted to the previous dry season) of the most frequent substrate tree, Clusia grandiflora (Clusiaceae), to upper leaves, better ventilated and whose orientation provides good protection from the rain. Therefore, the possibility of moving the nest higher during the first rains following the dry season seems very adaptive as colonies that do not do so are eliminated during the La Niña years, whose frequency will increase with global climate change.
ISSN: 1631-0691

hal-00817397
https://hal.archives-ouvertes.fr/hal-00817397
DOI : 10.1016/j.crvi.2009.10.007
PUBMED : 20176334

Éditeur(s) : HAL CCSD Wiley
Résumé : [b]Aim[/b][br/] [br/] The phylogeographical history of Neotropical species can be difficult to reconstruct because of superimposed Neogene and Quaternary histories, and because of taxonomic uncertainty. We analysed range-wide genetic diversity in a widespread pioneer tree species, Jacaranda copaia (Aubl.) D. Don, to characterize phylogeographical structure, date the evolutionary relationships among lineages, and evaluate the role of dispersal and vicariance in establishing the present geographical range.[br/] [br/] [br/] [b]Location[/b][br/] [br/] Guiana Shield; central, southern and western Amazon Basin; Chocó region; Central America.[br/] [br/] [br/] [b]Methods[/b][br/] [br/] We analysed nine nuclear simple sequence repeat loci (nuSSR), eight chloroplast SSRs (cpSSR), and two cpDNA intergenic sequences in 341 adult trees. Genetic differentiation at nuSSRs was inferred using Bayesian clustering. Dating of chloroplast lineage divergence was obtained using a range of published mutation rates and Bayesian coalescence analyses. Population divergence dating was performed using an isolation-with-migration model for eight loci (one cp sequence and seven nuSSRs).[br/] [br/] [br/] [b]Results[/b][br/] [br/] Nuclear SSR variation identified three geographically overlapping clusters (nu-1, nu-2, nu-3). Twelve cpDNA haplotypes were clustered into two haplogroups (cp-1, cp-2) with the central Amazon harbouring the highest diversity. Molecular dating analysis suggests that cpDNA haplotype diversification started around the end of the Pliocene (2.61 Ma on average), whereas population divergence was more recent and occurred during the mid-Quaternary (point estimates between 357 and 436 ka).[br/] [br/] [br/] [b]Main conclusions[/b][br/] [br/] The genetic variation of J. copaia in the Neotropics was shaped mainly by Pleistocene events. Chloroplast diversity did not display the expected cis/trans Andean disjunction, indicating recent dispersal. Nuclear variation revealed that separate regions share a recent history, with a centre of diversity in the central Amazon Basin. The geographical pattern of diversity is congruent with the distribution of the two subspecies, J. copaia copaia and J. copaia spectabilis, and evidence of nuSSR admixture between the two taxa supports their classification as subspecies.
ISSN: 0305-0270

hal-01032410
https://hal.archives-ouvertes.fr/hal-01032410
DOI : 10.1111/j.1365-2699.2012.02797.x