Éditeur(s) : HAL CCSD
Résumé : The Deep Basin of the Gulf of Mexico (DBGM) extends over eastern Mexico, the southeastern part of the United States, west of the Atlantic Ocean. This study, based on the interpretation and integration of seismic profiles, exploration wells and outcrop studies, focus on the deep part of the Gulf of Mexico, where bathymetry varies from 200 to 3750 m, thus comprising both the continental slope and the abyssal plain. The first part of this thesis focus on the description of the sedimentary infill of the western part of the Gulf of Mexico, in the Veracruz State, and to its geodynamic controls. The geodynamic evolution of the Deep Basin of the Gulf of Mexico (DBGM) begins during the Triassic-Jurassic with the break-up and the opening of a continental rift, in the southern part of the North American lithospheric plate. This opening induced a relative movement of the Yucatan Block towards the southeast. This intra-continental rifting episode was followed by a stage of post-rift thermal subsidence in the basins of the continental margin in the west, coeval with oceanic accretion in the DBGM. The thermal subsidence of the margin was subsequently modified by the Laramian orogeny, which impacted strongly the overall architecture of the margin as well as its litho-stratigraphic evolution, inducing the deposition of siliciclastic deposits in various morphotectonic provinces: i.e., near the tectonic front of the Sierra Madre Oriental (SMO), within the adjacent Chicontepec foreland basin, over the Tuxpan Platform (Golden Lane), across the continental slope and up to the deep abyssal plain, these two last morphotectonic provinces belonging to the DBGM. During the Early Paleogene, the effects of the thermal subsidence of the passive margin were stressed by the tectonic load of the Laramian orogen (i.e., the Sierra Madre Oriental, SMO), thus allowing the development of a foreland basin flexural. In this geodynamic framework, the main sedimentary transfers developed from the tectonic front "SMO" in the west, towards the DBGM in the east, the main source for clastic sediments being linked to the erosion of the "SMO" mountains. During the Paleocene and the Early Eocene, the architecture of the silici-clastic syn-tectonic sediments deposited in submarine fans was characterized by sliding, turbidites with A and B Bouma facies, as well as levees and channels. After the stop of the flexural subsidence, the thermal subsidence of the passive margin resumed during the Late Eocene, the Oligocene and the Neogene, allowing the development of a new sedimentary prism, prograding eastwards toward the DBGM. This sedimentary infill was again made up of levees-channels, sand bars and delta systems. During the Neogene, an extensional system with listric faults and roll-over features developed across the slope of the DBGM, due to an active detachment developing within overpressured Eocene-Oligocene clays. This gravitational gliding of Neogene series accounted also for the development of compressional features at the toe of the slope. Approximately 60% of the Miocene siliciclastic sediments have been trapped in growth strata and slope basins associated with this complex gravitational system, ranging from river-delta features towards gravity slides associated with slump facies. The second part of this thesis aims at a quantification of these various processes, including the construction of balanced cross sections, forward Thrustpack kinematic modelling coupling the development of a basal detachment, lithospheric flexure, erosion and sedimentation, as well as subsequent stratigraphic modelling with the Dionisos software, the later aiming at predicting the sand versus clay ratios in Neogene siliciclastic deposits of the DBGM and its surroundings.
Le bassin profond du Golfe du Mexique (BPMG) est localisé à l'est du Mexique, au sud-est des États-Unis et à l'ouest de l'Océan Atlantique. Cette étude de la partie profonde du Golfe du Mexique est basée sur l'intégration de données de sismique, de forages pétroliers et d'études de terrain; elle comprend toute la pente continentale et la plaine abyssale, avec une bathymétrie qui varie de 200 à 3750 m. La première partie de cette thèse est consacrée à la description du remplissage sédimentaire de la bordure occidentale du Golfe du Mexique, dans le secteur de Veracruz, en liaison avec son évolution géodynamique. L'évolution géodynamique du BPMG commence au Trias-Jurassique avec la rupture et la propagation d'un rift continental, dans le secteur sud de la plaque nord américaine. Cette ouverture et le déplacement relatif vers le sud-est du bloc crustal du Yucatan sont à l'origine du BPGM. Cette géodynamique de rift continental est suivie d'une étape post-rift accompagnée de l'océanisation du bassin. Les bassins de la marge passive ont poursuivi leur évolution sous l'effet de la subsidence thermique à l'ouest du Golfe du Mexique, tandis que de la croûte océanique se formait dans le BPGM. Cette subsidence thermique de la marge a ensuite été perturbée par l'orogénèse Laramienne, qui a remodelé l'architecture stratigraphique silico-clastique des dépôts du Tertiaire entre les éléments morphotectoniques suivants: lefront tectonique de la Sierra Madre Orientale (SMO), le bassin d'avant-pays Chicontepec, la Plateforme de Tuxpan-Faja de Oro, la pente continentale et la plaine abyssale, ces deux dernières provinces morphotectoniques appartenant au BPGM. Pendant le Paléogèneinférieur, les effets de la subsidence thermique de la marge passive ont été accentués par la charge tectonique de l'orogénèse laramienne (SMO), permettant ainsi le développement d'un bassin flexural d'avant-pays. Au cours de cette étape, les principaux transferts sédimentaires se sont effectués du front tectonique "SMO" vers le BPGM. La source principale de sédiments clastiques est liée à l'érosion de la chaîne de montagnes "SMO". Pendant le Paléocène et l'Éocène inférieur, l'architecture des premiers sédiments silico-clastiques syn-tectoniques déposés dans des éventails sous-marins sont caractérisés par des figures de glissement, des faciès turbiditiques A et B de Bouma, des chenaux-levées. Après l'arrêt de la subsidence flexurale, la subsidence thermique de la marge passive s'est poursuivie pendant l'Éocène supérieur, l'Oligocène et le Néogène, permettant le développement d'un nouveau prisme sédimentaire progradant. Les remplissages sédimentaires sont encore constitués de chenaux et de levées, avec des barres de sable associées à des systèmes deltaïques sur la plateforme. Pendant le Néogène, un système de failles listriques s'est développé sur la pente du BPGM, au-dessus d'une surface de décollement située, dans la région d'étude, dans les argiles de l'Éocène-Oligocène. Ce système de failles de croissance a piégé plus de 60% des sédiments silico-clastiques du Miocène. Ce remplissage sédimentaire évolue latéralement de faciès fluviaux deltaïques vers des faciès de pente affectés de glissements gravitaires et associés à des turbidites. La deuxième partie de cette thèse est consacrée à une approche quantitative basée sur des modélisations structurales (coupes équilibrées et modélisations cinématiques directes avec Thrustpack, couplant décollement gravitaire, flexure lithosphérique, érosion et sédimentation), puis sédimentaires (prise en compte des transferts de matériel clastique depuis la partie émergée de la chaîne jusqu'au bassin profond, à l'aide du logiciel Dionisos, afin de mieux comprendre les processus de piégeage des sédiments grossiers dans les structures de croissance et les bassins perchés de la marge.
https://tel.archives-ouvertes.fr/tel-00435120

tel-00435120
https://tel.archives-ouvertes.fr/tel-00435120
https://tel.archives-ouvertes.fr/tel-00435120/document
https://tel.archives-ouvertes.fr/tel-00435120/file/thesealzaga.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Experimentally Assisted Molecular Modelling (EAMM) is an original approach for predicting the structure of organic micro-crystals and deducing their habit in the presence of various solvents and additives. It is applied here in the case of n-octylamino-nitrobenzoxadiazole (nOA-NBD), a fluorescent compound. This general approach is first of all described and validated by its blind application to three known and closely-related crystals. Then, the whole process is applied to predict the molecular crystal generated by n-octylamino-NBD, including the molecule conformation, its structure (cell parameters, molecular packing, X-ray powder diagrams) and its theoretical plus actual habits in the presence of a solvent (p-xylene) and two additives (acetic acid and n-dodecane). The conformation of the predicted molecule is validated by comparison with two similar molecules embedded in observable crystals. Then, the choice between two proposed structures (with the same energy and two equiprobable packings) is based on the comparison between experimental and re-computed X-ray powder diffraction diagrams, and also on the interpretation of an actual TEM image in the light of the proposed cell parameters. This choice is confirmed by the comparison between the vapour-grown face development (proposed by the BFDH or the attachment energy models) and the actual face development in a pure solvent. Finally, the actual habit deduced from comparing the crystal attachment energy with the adsorption energy of solvent or additive molecules is validated by SEM images of NBD micro-crystals in presence of the solvent alone or in presence of both additives. In conclusion, the EAMM approach appears to be a decisive tool for quickly simulating structural and habit properties of the molecular crystals, accessible or not by experimentation. Thus, a numerical selection of molecules becomes possible in view of deriving organic materials with predetermined properties, such as the fluorescence properties of the compound considered in the present study.
ISSN: 0022-0248

hal-00857894
https://hal.archives-ouvertes.fr/hal-00857894
DOI : 10.1016/j.jcrysgro.2011.07.035

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Background and Aims: In rain forests, sapling survival is highly dependent on the regulation of trunk slenderness (height/diameter ratio): shade-intolerant species have to grow in height as fast as possible to reach the canopy but also have to withstand mechanical loadings (wind and their own weight) to avoid buckling. Recent studies suggest that mechanosensing is essential to control tree dimensions and stability-related morphogenesis. Differences in species slenderness have been observed among rainforest trees; the present study thus investigates whether species with different slenderness and growth habits exhibit differences in mechanosensitivity. Methods: Recent studies have led to a model of mechanosensing (sum-of-strains model) that predicts a quantitative relationship between the applied sum of longitudinal strains and the plant's responses in the case of a single bending. Saplings of five different neotropical species (Eperua falcata, E. grandiflora, Tachigali melinonii, Symphonia globulifera and Bauhinia guianensis) were subjected to a regimen of controlled mechanical loading phases (bending) alternating with still phases over a period of 2 months. Mechanical loading was controlled in terms of strains and the five species were subjected to the same range of sum of strains. The application of the sum-of-strain model led to a dose-response curve for each species. Dose-response curves were then compared between tested species. Key Results: The model of mechanosensing (sum-of-strain model) applied in the case of multiple bending as long as the bending frequency was low. A comparison of dose-response curves for each species demonstrated differences in the stimulus threshold, suggesting two groups of responses among the species. Interestingly, the liana species B. guianensis exhibited a higher threshold than other Leguminosae species tested. Conclusions: This study provides a conceptual framework to study variability in plant mechanosensing and demonstrated interspecific variability in mechanosensing.
ISSN: 0305-7364

halsde-00454145
https://hal.archives-ouvertes.fr/halsde-00454145
DOI : 10.1093/aob/mcp286

Éditeur(s) : HAL CCSD EDP Sciences
Résumé : International audience
The dynamic model of plant growth GreenLab describes plant architecture and functional growth at the level of individual organs. Structural development is controlled by formal grammars and empirical equations compute the amount of biomass produced by the plant, and its partitioning among the growing organs, such as leaves, stems and fruits. The number of organs initiated at each time step depends on the trophic state of the plant, which is evaluated by the ratio of biomass available in plant to the demand of all the organs. The control of the plant organogenesis by this variable induces oscillations in the simulated plant behaviour. The mathematical framework of the GreenLab model allows to compute the conditions for the generation of oscillations and the value of the period according to the set of parameters. Two case-studies are presented, corresponding to emergence of oscillations associated to fructification and branching. Similar alternating patterns are commonly reported by botanists. In this article, two examples were selected: alternate patterns of fruits in cucumber plants and alternate appearances of branches in Cecropia trees. The model was calibrated from experimental data collected on these plants. It shows that a simple feedback hypothesis of trophic control on plant structure allows the emergence of cyclic patterns corresponding to the observed ones.
ISSN: 0973-5348

hal-00780592
https://hal-ecp.archives-ouvertes.fr/hal-00780592
https://hal-ecp.archives-ouvertes.fr/hal-00780592/document
https://hal-ecp.archives-ouvertes.fr/hal-00780592/file/Mathieu_2012_Published_mmnp201276p47.pdf
DOI : 10.1051/mmnp/20127603

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Chromatin modification enzymes are important regulators of gene expression and some are evolutionarily conserved from yeast to human. Saccharomyces cerevisiae is a major model organism for genome-wide studies that aim at the identification of target genes under the control of conserved epigenetic regulators. Ume6 interacts with the upstream repressor site 1 (URS1) and represses transcription by recruiting both the conserved histone deacetylase Rpd3 (through the co-repressor Sin3) and the chromatin-remodeling factor Isw2. Cells lacking Ume6 are defective in growth, stress response, and meiotic development. RNA profiling studies and in vivo protein-DNA binding assays identified mRNAs or transcript isoforms that are directly repressed by Ume6 in mitosis. However, a comprehensive understanding of the transcriptional alterations, which underlie the complex ume6Δ mutant phenotype during fermentation, respiration, or sporulation, is lacking. We report the protein-coding transcriptome of a diploid MAT a/α wild-type and ume6/ume6 mutant strains cultured in rich media with glucose or acetate as a carbon source, or sporulation-inducing medium. We distinguished direct from indirect effects on mRNA levels by combining GeneChip data with URS1 motif predictions and published high-throughput in vivo Ume6-DNA binding data. To gain insight into the molecular interactions between successive waves of Ume6-dependent meiotic genes, we integrated expression data with information on protein networks. Our work identifies novel Ume6 repressed genes during growth and development and reveals a strong effect of the carbon source on the derepression pattern of transcripts in growing and developmentally arrested ume6/ume6 mutant cells. Since yeast is a useful model organism for chromatin-mediated effects on gene expression, our results provide a rich source for further genetic and molecular biological work on the regulation of cell growth and cell differentiation in eukaryotes.
ISSN: 1617-4615

hal-01151619
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01151619
DOI : 10.1007/s00438-015-1051-5
PUBMED : 25957495

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The extinct Odontopterygiformes are the sole birds known to possess strong and sharp bony pseudoteeth, the shape and location of which are closely mimetic of real teeth. The structure of the pseudoteeth is investigated here in a late Pliocene/early Pleistocene species, Pelagornis mauretanicus, using X-ray microtomography and thin sections. The results are interpreted with regard to the pseudotooth mode of growth, and have implications concerning aspects of Pelagornis ecology. The larger pseudoteeth are hollow and approximately cone-shaped, and the smaller ones are rostro-caudally constricted. The walls of pseudoteeth are composed of bone tissue of the fibro-lamellar type, which is intensively remodeled by Haversian substitution. The jaw bones display the same structure as the pseudoteeth, but their vascular canals are oriented parallel to the long axis of the bones, whereas they are perpendicular to this direction in the pseudoteeth. There is no hiatus or evidence of a fusion between the pseudoteeth and the jaw bones. Two possible models for pseudotooth growth are derived from the histological data. The most plausible model is that pseudotooth growth began after the completion of jaw bone growth, as a simple local protraction of periosteal osteogenic activity. Pseudotooth development thus occurred relatively late during ontogeny. The highly vascularized structure and the relative abundance of parallel-fibered bone tissue in the pseudoteeth suggest poor mechanical capabilities. The pseudoteeth were most likely covered and protected by the hardened, keratinized rhamphotheca in the adult during life. The late development of the pseudoteeth would involve a similarly late and/or partial hardening of the rhamphotheca, as displayed by extant Anseriformes, Apterygiformes and some Charadriiformes. This would add support to the hypothesis of a close phylogenetic relationship between Odontopterygiformes and Anseriformes. The late maturation of the Pelagornis feeding apparatus, and hence the delayed capability for efficient prey catching, suggests that Pelagornis was altricial.
ISSN: 1932-6203

hal-01545486
https://hal.archives-ouvertes.fr/hal-01545486
DOI : 10.1371/journal.pone.0080372

Éditeur(s) : Université de la Polynésie Française
Résumé : The ontogeny of osmoregulation was studied in the blue shrimp Litopenaeus stylirostris in New Caledonia. The implication of branchial organs in ionic regulation was first demonstrated in juveniles by immunolocalization of three ion transporting proteins ( namely NKA, co-transporter NKCC1 and CFTR ) and ionocyte detection was done by means of electron microscopy. The role of the main ion transporting enzyme, NKA, was subsequently investigated during post-embryonic development using an integrative approach associating physiological, histological, immunological and biomolecular studies. Results obtained allowed us to propose a model of the osmoregulatory pattern in L. stylirostris based on weak regulation in the early stages, then progressively this species acquires the adult pattern of hyper-hypo-regulation after metamorphosis with the concurrent development of epipodites and gills. Strong NKA immunofluorescence and abundance of NKA transcripts in these two tissues compared to others organs suggest their functional implication in osmoregulatory processes. The results of this study allow us to increase our knowledge of the penaeid shrimp osmoregulation and to propose zootechnical measures to improve the animal physiological comfort. These propositions have been already tested during larval rearing trials, leading a two-fold-growth in 19 days-old postlarvae.
L’étude de l’ontogenèse de l’osmorégulation a été entreprise chez la crevette bleue Litopenaeus stylirostris en Nouvelle-Calédonie. L’implication des tissus de la cavité branchiale dans la régulation ionique a été déterminée au préalable chez des juvéniles par immunolocalisation de trois transporteurs protéiques d’ions, ( la NKA, le co-transporteur NKCC1 et le CFTR ) et par la détection de ionocytes en microscopie électronique. Le rôle de la NKA a été particulièrement étudié et son implication a été examinée au cours du développement post-embryonnaire par une approche intégrative associant des études physiologiques, histologiques, immunologiques et moléculaires. Cette démarche nous a permis de proposer un modèle d’osmorégulation chez L. stylirostris: de faible régulatrice dans les premiers jours de sa vie, cette espèce évolue vers l’hyper-hypo-régulation après la métamorphose avec le développement progressif des épipodites et des branchies. L’immunofluorescence prononcée de la NKA ainsi que l’abondance des transcrits du gène codant la NKA dans les tissus de ces deux organes suggèrent leur implication fonctionnelle dans l’ionorégulation. Les résultats de ce travail nous ont permis d’accroître nos connaissances sur l’osmorégulation chez les pénéidés et de proposer des améliorations zootechniques visant à augmenter leur confort physiologique. Ces préconisations ont fait l’objet de premiers essais en conditions d’élevage et se sont traduites par un doublement de la croissance des post-larves de 19 jours.

Droits : 2011 The author, Univ. Polynésie Française
http://archimer.ifremer.fr/doc/00052/16314/13816.pdf
http://archimer.ifremer.fr/doc/00052/16314/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The growth of relief in active tectonic areas is mainly controlled by the interactions between tectonics and surface processes (erosion and sedimentation). The study of long-lived morphologic markers formed by these interactions can help in quantifying the competing effects of tectonics, erosion and sedimentation. In regions experiencing active extension, river-long profiles and faceted spurs (triangular facets) can help in un- derstanding the development of mountainous topography along normal fault scarps. In this study, we devel- oped analogue experiments that simulate the morphologic evolution of a mountain range bounded by a normal fault. This paper focuses on the effect of the fault slip rate on the morphologic evolution of the foot- wall by performing three analogue experiments with different fault slip rates under a constant rainfall rate. A morphometric analysis of the modelled catchments allows comparing with a natural case (Tunka half- graben, Siberia). After a certain amount of fault slip, the modelled footwall topographies of our models reaches a dynamic equilibrium (i.e., erosion balances tectonic uplift relative to the base level) close to the fault, whereas the topography farther from the fault is still being dissected due to regressive erosion. We show that the rates of vertical erosion in the area where dynamic equilibrium is reached and the rate of re- gressive erosion are linearly correlated with the fault throw rate. Facet morphology seems to depend on the fault slip rate except for the fastest experiment where faceted spurs are degraded due to mass wasting. A stream-power law is computed for the area wherein rivers reach a topographic equilibrium. We show that the erosional capacity of the system depends on the fault slip rate. Finally, our results demonstrate the pos- sibility of preserving convex river-long profiles on the long-term under steady external (tectonic uplift and rainfall) conditions.
ISSN: 0040-1951

hal-00646966
https://hal.archives-ouvertes.fr/hal-00646966
https://hal.archives-ouvertes.fr/hal-00646966/document
https://hal.archives-ouvertes.fr/hal-00646966/file/preprint_Strak_2011.pdf
DOI : 10.1016/j.tecto.2011.10.005

Éditeur(s) : Elsevier Science Bv
Résumé : We developed a growth model for Crassostrea gigas oyster shells based on the use of in situ temporal manganese markings to calibrate natural cathodoluminescence (CL) changes in the shell hinge sections. A 30 min to 4-h exposure period with Mn2+ (90-120 mg l(-1)) was sufficient to create a detectable mark in the shells. This makes the Mn2+ markings the fastest mollusc shells marking technique to date. The natural CL from juvenile and adult shells cultured in four standard shellfish-farming locations along the English Channel and French Atlantic coasts, exhibited a seasonal pattern (maximum CL intensity occurring during summer periods, minimum CL intensity occurring during winter). Hydrobiological data recorded at Baie des Veys site allows us to attribute the seawater temperature as the main parameter controlling CL of shells. Chlorophyll a and seawater manganese concentration were not decisive in the luminescence intensity of the shells. A relationship between oyster hinge growth and the length of shells makes the umbo investigations a promising tool for oyster-farming and/or wild stock assessments. Shell growth varied at spatial and temporal scales (higher growth rates were observed during summer-autumn and lower during the winter period), depending on seawater temperature changes. Sub-monthly Mn2+ markings support the fact that shell deposition can occur under temperatures below 6 degrees C, which has to be taken into account for both shellfish production and environmental monitoring derived from chemical compositions of the shells. Finally, our results point out the efficiency of age and shell growth rate determination by CL analysis in further shellfish ecosystem researches.
Aquaculture (0044-8486) (Elsevier Science Bv), 2010-02 , Vol. 300 , N. 1-4 , P. 206-217

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00002/11300/7912.pdf
DOI:10.1016/j.aquaculture.2009.12.018
http://archimer.ifremer.fr/doc/00002/11300/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Tectonically controlled landforms develop morphologic features that provide useful markers to investigate crustal deformation and relief growth dynamics. In this paper, we present results of morphotectonic experiments obtained with an innovative approach combining tectonic and surface processes (erosion, transport, and sedimentation), coupled with accurate model monitoring techniques. This approach allows for a qualitative and quantitative analysis of landscape evolution in response to active deformation in the three end-member geological settings: compression, extension, and strike–slip.Experimental results outline first that experimental morphologies evolve significantly at a short time scale. Numerous morphologic markers form continuously, but their lifetime is generally short because erosion and sedimentation processes tend to destroy or bury them. For the compressional setting, the formation of terraces above an active thrust appears mainly controlled by narrowing and incision of the main channel through the uplifting hanging-wall and by avulsion of deposits on fan-like bodies. Terrace formation is irregular even under steady tectonic rates and erosional conditions. Terrace deformation analysis allows retrieving the growth history of the structure and the fault slip rate evolution. For the extensional setting, the dynamics of hanging-wall sedimentary filling appears to control the position of the base level, which in turn controls footwall erosion. Two phases of relief evolution can be evidenced: the first is a phase of relief growth, and the second is a phase of upstream propagation of topographic equilibrium that is reached first in the sedimentary basin. During the phase of relief growth, the formation of triangular facets occurs by degradation of the fault scarp, and their geometry (height) becomes stationary during the phase of upstream propagation of the topographic equilibrium. For the strike–slip setting, the complex morphology of the wrench zone, composed of several interacting fault segments, enhances the interactions with the drainage network. Because of the widening of the main fault zone toward the surface, a significant amount of distributed deformation is observed along the wrench zone. Locally, where two terminations of fault segments interact, less than a quarter of the far field displacement can remain measurable using fault offsets, leading to a systematic underestimation of the real fault slip rate.These different experimental examples illustrate the great potential of the approach coupling deformation mechanisms and erosion–transport–sedimentation processes to investigate qualitatively and quantitatively the morphotectonic evolution of tectonically controlled landscapes.
ISSN: 0169-555X

hal-01243587
https://hal.archives-ouvertes.fr/hal-01243587
DOI : 10.1016/j.geomorph.2015.02.011

Éditeur(s) : HAL CCSD
Résumé : International audience
The study of complex biological processes requires to forgo simplified models for extensive ones. Yet, these models' size and complexity place them beyond understanding. Their analysis requires new methods for identifying general patterns. The Transforming Growth Factor TGF-β is a multifunctional cytokine that regulates mammalian cell development , differentiation, and homeostasis. Depending on the context, it can play the antagonistic roles of growth inhibitor or of tumor promoter. Its context-dependent pleiotropic nature is associated with complex sig-naling pathways. The most comprehensive model of TGF-β-dependent signaling is composed of 15,934 chains of reactions (trajectories) linking TGF-β to at least one of its 159 target genes. Identifying functional patterns in such a network requires new automated methods. This article presents a framework for identifying groups of similar trajec-tories composed of the same molecules using an exhaustive and without prior assumptions approach. First, the trajectories were clustered using the Relevant Set Correlation model, a shared nearest-neighbors clustering method. Five groups of trajectories were identified. Second, for each cluster the over-represented molecules were determined by scoring the frequency of each molecule implicated in trajectories. Third, Gene set enrichment analysis on the clusters of trajectories revealed some specific TGF-β-dependent biological processes, with different clusters associated to the antagonists roles of TGF-β. This confirms that our approach yields biologically-relevant results. We developed a web interface that facilitates graph visualization and analysis. Our clustering-based method is suitable for identifying families of functionally-similar trajectories in the TGF-β signaling network. It can be generalized to explore any large-scale biological pathways.
CMSB 2017 - 15th International Conference on Computational Methods in Systems Biology
Darmstadt, France

hal-01559249
https://hal.archives-ouvertes.fr/hal-01559249
https://hal.archives-ouvertes.fr/hal-01559249/document
https://hal.archives-ouvertes.fr/hal-01559249/file/JeanCoquet_CMSB.pdf

Résumé : L'importance des forêts tropicales dans le cycle du carbone à l'échelle planétaire est majeure, tant en terme de stock qu’en terme de flux de CO2. Plusieurs études mettent en évidence des changements au sein des forêts tropicales au cours des 20 dernières années, notamment des changements de la dynamique forestière et une augmentation de la biomasse aérienne. Les déterminants de ces variations sont aujourd’hui discutés et nous proposons ici d’apporter une contribution à ce débat. Les données utilisées dans ce travail proviennent du dispositif de suivi forestier à long terme de Paracou, Guyane Française, mis en place en 1984 et qui recouvre plus de 120 ha de forêt tropicale humide. Les données météorologiques proviennent de la tour à flux du dispositif, Guyaflux. Les mesures de diamètre proviennent de la base Guyafor pour les données annuelles et bisannuelles, et des mesures de 260 arbres à proximité de la tour à flux pour les mesures diamétriques intra-annuelles.Cette thèse se divise en deux grandes parties. La première concerne l’analyse de la biomasse du dispositif de suivi forestier de Paracou en Guyane et l’implication des changements de structure de cette forêt sur le bilan de carbone. Cette partie est constituée de deux points. (i) Quelles échelles temporelles et spatiales sont pertinentes pour analyser les composantes de structure (biomasse, aire basale et nombre de tiges) et de dynamique (croissance, recrutement et mortalité) des forêts tropicales afin de minimiser les effets d’échantillonnage ? Nous avons établi une méthodologie permettant de relier les intervalles de temps et la surface de mesure aux coefficients de variation de chacune des variables de structure et de dynamique de la forêt. (ii) Quels processus démographiques sont prépondérants dans l’explication des variations de biomasse et comment se redistribue la biomasse accumulée dans le système ? L’augmentation de la biomasse observée sur le dispositif de Paracou serait liée à la rareté des évènements de mortalité des gros arbres qui portent une part très importante de la biomasse.La deuxième partie de la thèse concerne l’analyse de l’effet du climat à moyen terme, inter et intra-annuel, et les effets directs du climat dans les changements de dynamique de la forêt. Cette partie se divise en 3 points. (i) Comment quantifier le stress hydrique en forêt tropicale humide ? Nous avons réalisé un modèle journalier de réserve en eau du sol pour les arbres en forêt tropicale. (ii) Quelles variables sont explicatives de la croissance des arbres en forêt guyanaise ? Nous avons montré que l’eau dans le sol est le facteur le plus explicatif du déterminisme climatique parmi un panel de variables climatiques. (iii) Quels traits fonctionnels sont prédicteurs de la réponse des arbres aux variations climatique ? Nous avons déterminé que des traits spécifiques, densité du bois et la hauteur maximale, ainsi que le diamètre de l'arbre au moment de la mesure, modulent la croissance des arbres en réponse au climat.
At a global scale tropical forest play a major role in term of carbon stock as well as in term of CO2 fluxes. Several studies have highlighted changes in tropical forest functioning during the last 20 years including a faster turnover and an increase of above ground biomass. The drivers of these changes are discussed and throughout this thesis we propose to contribute to this debate. We use the data from the Paracou experimental site in French Guiana established in 1984 on 120 hectares of moist tropical forest. Meteorological data come from the flux tower of the site, Guyaflux. We use annual and bisannual diameter measurements from the Guyafor database, and intra-annual diameter increments from the measurements of 260 trees near the flux tower.This thesis has two main parts. In the first part we present the biomass analysis of the Paracou permanent plots and the impact of structural changes in this forest on the carbon budget. The first part is constituted by two points. (i) Which temporal and spatial scale used to analyze the structure (biomass, basal area and stem density) and dynamics (tree growth, recruitment and mortality)components of tropical forest in order to minimized sample bias ? We establish a simple method to rely measurement interval between census and surface of measurement to the coefficient of variation of forests structure and dynamic components (ii) Which demographic process are involved in the explanation of biomass variation and how the biomass is distributed in the system ? The observed increase of biomass at Paracou could be link to the rarity of big trees mortality events. These big trees represent the larger part of the biomass. In the second part, we present the analysis of intra and inter-annual climate variation effects on forest dynamic changes. This part is divided in two points. (i) How to model drought stress in moist tropical forest ? We built a daily water balance model for tropical trees. (ii) Which climate variables explain the tree growth in guianian forests? We shown that soil water availability is the determinant factor of tree growth among a panel of climate variables. (iii) Which functional traits are involved in the tropical tree growth responses to climate? In this analysis, we determined that wood specific gravity, maximum tree height and tree diameter modulate the tree growth response to climate variations.

http://www.theses.fr/2011AGUY0481/document

Résumé : Chez la banane dessert, les saveurs sucrée et acide, caractéristiques importantes pour les consommateurs, sont pilotées par les teneurs en acides citrique et malique. Ce travail a donc porté sur l’étude des processus physiologiques qui pilotent l’accumulation de ces acides dans la pulpe de banane (Musa sp. AA) en combinant analyse expérimentale et modélisation écophysiologique. Nous nous sommes notamment intéressés à l’effet du génotype et des conditions de croissance du fruit en adoptant une approche intégrative liant les phases pré et post récolte.Les effets de la charge en fruit, de la fertilisation potassique, et du stade de récolte sur l’accumulation du citrate et du malate dans la pulpe ont été étudiés expérimentalement. La variabilité génotypique a été prise en compte en choisissant trois génotypes présentant des acidités contrastées à maturité. Des différences d’évolution des teneurs en acides, dues à des modifications métaboliques, ont été observées entre les génotypes pendant les phases pré et post récolte. Le stade de récolte a eu un effet significatif sur les teneurs en acides des fruits pendant la maturation post récolte. La charge en fruit et la fertilisation potassique n’en ont eu aucun. Des modèles écophysiologiques ont été développés pour prédire différents critères d’acidité de la banane en pré et post récolte. Le pH et l’acidité titrable ont été prédits par un modèle d’équilibres acido-basiques, la teneur en malate par un modèle de stockage vacuolaire, et la teneur en citrate par un modèle du cycle de Krebs. Ces modèles ont permis d’identifier les processus physiologiques clés qui pilotent l’acidité de la banane. Des paramètres génotypiques ont été identifiés liés à l’activité de l’enzyme malique mitochondriale et à celle des transporteurs mitochondriaux du malate pour le modèle citrate, et à l’activité des pompes à protons vacuolaire ATPases pour le modèle malate. Ces modèles ont également permis de disséquer l’effet des conditions de croissance du fruit sur l’acidité de la banane. L’intégration des modèles développés dans un modèle d’élaboration de l’acidité et son utilisation potentielle pour l’amélioration variétale sont discutées.
Citric and malic acids determine the sourness and sweetness of banana pulp, which are the two main determinants of consumer preferences. The present work focused on the physiological processes controlling the accumulation of citric and malic acids in banana pulp (Musa sp. AA) using experimental analysis and ecophysiological modeling. We chose an integrative approach linking the pre and post-harvest stages, and focused on the effect of genotype and fruit growing conditions. Experiments were conducted to study the effect of fruit load, potassium fertilization and fruit age at harvest on the accumulation of citrate and malate in banana pulp. To account for genotypic variability, three genotypes with contrasting acidity at the eating stage were studied. Major differences in the pattern of citrate and malate accumulation were found in the three cultivars both during growth and post-harvest ripening and were shown to be the result of metabolic changes. The harvest stage had a significant effect on the concentrations of acids during post-harvest ripening. Fruit load and potassium fertilization had no effect.Ecophysiological models were developed to predict several banana acidity criteria during the pre and post harvest stages. pH and titratable acidity were predicted by a model of acid-base reactions; malate content by a model of vacuolar storage; and citrate content by a model of the TCA cycle. These models led to the identification of the key physiological processes that control banana acidity. Genotypic parameters were identified, which were related to the activity of the mitochondrial malic enzyme and of the malate mitochondrial carriers in the citrate model, as well as to the activity of the vacuolar proton pump, ATPase, in the malate model. The two models were also used to analyze the effects of fruit growth conditions on banana acidity.Combining the three models in a global model of banana acidity, and the possible use of this model for varietal improvement are discussed.

http://www.theses.fr/2014AGUY0777/document

Éditeur(s) : Agro Paris Tech
Résumé : P. acidilactici MA 18/5M is a dietary probiotic (BACTOCELL®) which has shown its efficiency on several terrestrial and aquatic species. The present thesis aimed to investigate more fully the effects of this probiotic on cultured penaeid shrimps. For this study, we chose a global approach by replacing the problem studied in a model of interactions between three compartments: the shrimp, its intestinal microflora and the probiotic. Having first defined how the probiotic should be administrated, we studied its effects under controlled laboratory conditions at several levels of Litopenaeus stylirostris biology: (i) Nutritional status and growth, (ii) associated bacterial microflora, and (iii) health status with respect to oxidative stress. Then the probiotic improves the growth of the shrimps and the feed conversion ratio. Our study shows that these effects are partially due to a better use of the feed, particularly of dietary carbohydrates, but also suggest an action on the metabolism, andor on the growth via a contribution of essential nutrients. On the other hand, although the intestinal bacterial communities seems little affected, we show an antagonism effect of the probiotic toward total and vibrionacea intestinal flora, as well as a decrease in the level of infection of shrimps during challenge with pathogenic V. nigripulchritudo. Beside, our works highlight that infection by this pathogen, led to a reduction in antioxidant defences, to a rise in oxidative damages, and to a release of mortalities within 48 hours. This oxidative stress following bacterial infection was better controlled by animals receiving the probiotic diet, and resistance of the shrimps to infection was significant improved. A nutritional hypothesis is proposed to explain such result, hypothesis based on a link between carbohydrate metabolism and antioxidant status. As a conclusion of these works, we can propose a first explanatory scenario for the effects of P. acidilactici on a penaeid shrimp. Finally probiotic's effects were assessed under a pilot scale in a commercial farm from New Caledonia currently affected by the "summer syndrome ". We confirm the improvements brought in term of zootechnical results, with in particular, a better resistance to this syndrome. This work was made possible thanks to a breeding method in floating cages, developed during this thesis, and therefore transferred, as an experimental tool, to the shrimp industry of New Caledonia.
Pediococcus acidilacticii MA18/5M est un probiotique bactérien (BACTOCELL®) qui a démontré son efficacité chez plusieurs espèces d'animaux terrestres et aquatiques. Cette thèse avait pour objectif d'investiguer plus en détails les effets de ce probiotique chez les crevettes pénéides d'élevage. Pour cette étude, nous avons choisi une approche globale replaçant la problématique dans un modèle d'interactions entre trois compartiments : la crevette, sa microflore intestinale et le probiotique. Après avoir défini les modalités d'administration, l'effet de P. acicilactici a été étudié, en conditions de laboratoire, chez la crevette Litopenaeus stylirostris, à différents niveaux: (i) statut nutritionnel et croissance, (ii) microflore bactérienne associée, et (iii) santé de l'animal à travers son statut antioxydant et son niveau de stress oxydant. Ainsi, le probiotique améliore la croissance des crevettes et l'indice de conversion de l'aliment. Notre étude montre que ces effets sont en partie liés à une meilleure utilisation de l'aliment, notamment des carbohydrates alimentaires, mais suggèrent aussi une action sur le métabolisme, et/ou sur la croissance via un apport de nutriments essentiels. D'autre part, bien que les communautés bactériennes intestinales semblent peu affectées, un effet d'antagonisme du probiotique vis-à-vis de la flore intestinale totale et vibrionacée a été montré, ainsi qu'une réduction du niveau d'infection des crevettes au cours de challenge avec le pathogène V. nigripulchritudo. Par ailleurs, nous mettons en évidence que l'infection par ce pathogène, conduit à un abaissement des défenses antioxydantes, à une élévation des dégâts oxydatifs, et au déclenchement de mortalités dans les 48 heures. Le probiotique atténue le niveau de ce stress oxydant, et améliore significativement la résistance des crevettes à l'infection. Une hypothèse nutritionnelle est proposée afin d'expliquer ce résultat, hypothèse reposant sur un lien entre le métabolisme des carbohydrates et le statut antioxydant. A l'issue de ces travaux, nous pouvons alors proposer un premier scénario explicatif des effets de P. acidilactici chez une crevette pénéide. Finalement le probiotique a été éprouvé à l'échelle pilote sur une ferme commerciale de Nouvelle-Calédonie affectée par le « syndrome d'été ». Nous confirmons les améliorations apportées en termes de résultats zootechniques, avec notamment une meilleure résistance au syndrome. Ce travail a été réalisé grâce une méthode d'élevage en cages flottantes, mis au point au cours de cette thèse, et qui a dés lors été transférée, comme outil expérimental, à la filière crevetticole Calédonienne.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2009/these-6814.pdf
http://archimer.ifremer.fr/doc/00000/6814/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This study explores the dynamics of porosity and reactive surface area changes during porous limestone dissolution by CO2-rich water. The Sr and Ca concentrations in both the rock and the outlet solution are used to evaluate the reactive surface area changes of the two rock-forming calcites, i.e. micrite grains and sparite crystals, which have different trace element signatures. The geometric surface area measured with X-ray microtomography decreases slightly whereas the reactive surface area increases continuously with increasing porosity from 20.3 to 30.2%. Surprisingly, changes in reactive surface areas are very different between the two calcites. The reactive surface area changes in the micrite are parabolic while the reactive surface area of sparite increases greatly. The numerical model HYTEC is used to model the change in reactive surface areas during the experiment. Different geometrical models are tested. The model based on spherical-grain dissolution and spherical-pore growth fails to reproduce the experimental results, while the sugar-lump model provides reasonable agreement with the experiment.
ISSN: 0009-2541

hal-00445274
https://hal.archives-ouvertes.fr/hal-00445274
DOI : 10.1016/j.chemgeo.2009.01.032

Éditeur(s) : HAL CCSD
Résumé : International audience
In all vertebrate species, estrogens play a crucial role in the development, growth, and function of reproductive and nonreproductive tissues. A large number of natural or synthetic chemicals present in the environment and diet can interfere with estrogen signaling; these chemicals are called endocrine disrupting chemicals (EDCs) or xenoestrogens. Some of these compounds have been shown to induce adverse effects on human and animal health, and some compounds are suspected to contribute to diverse disease development. Because xenoestrogens have varying sources and structures and could act in additive or synergistic effects when combined, they have multiple mechanisms of action. Consequently, an important panel of in vivo and in vitro bioassays and chemical analytical tools was used to screen, evaluate, and characterize the potential impacts of these compounds on humans and animals. In this paper, we discuss different molecular actions of some of the major xenoestrogens found in food or the environment, and we summarize the current models used to evaluate environmental estrogens.
Int J Endocrinol

Droits : info:eu-repo/semantics/OpenAccess
inserm-00863365
http://www.hal.inserm.fr/inserm-00863365
http://www.hal.inserm.fr/inserm-00863365/document
http://www.hal.inserm.fr/inserm-00863365/file/501851.pdf
PUBMED : 23737774

Éditeur(s) : HAL CCSD
Résumé : Cell signaling contains the whole biological mecanisms allowing the response of a cell to its microenvironnement in an adapted way. Many extremely intertwinned biological reactions are involved in a network that behaves as a complex system. The understanding of cell response requires the development of data acquisition technics and methods to formalize data into models. This point is the main drive of this thesis. We present here two approaches in order to analyse different granularities of cell signaling. In the first one, we used differential model to study the role of a new component of TGF-β canonical pathway. In the second one, we explored the combinatorial complexity of cell signaling, developing a discrete formalism based on guarded transitions. In this approach, we interpreted the whole database Pathway Interaction Database into a single unified model of signal transduction. Simulation and analysis methods, such as reachability and invariance research, have been developed. The interests are presented through an application on cell cycle regulation by cell signaling, and a global analysis on the regulation of genes compared to experimental data.
La signalisation cellulaire regroupe l'ensemble des mécanismes biologiques permettant à une cellule de répondre de façon adaptée à son microenvironnement. Pour ce faire, de nombreuses réactions biologiques entrent en jeux avec un important enchevêtrement, créant ainsi un réseau dont le comportement s'apparente à un système complexe. Le compréhension de la réponse cellulaire à une stimulation passe par le développement conjoint des techniques d'acquisition de données, et des méthodes permettant de formaliser ces données dans un modèle. C'est sur ce dernier point que s'inscrivent les travaux exposés dans cette thèse. Nous présentons ici deux approches visant à répondre à des questions de natures différentes sur la signalisation cellulaire. Dans la première nous utilisons un modèle différentiel pour étudier le rôle d'un nouvel interactant dans la voie canonique du TGF-beta. Dans la seconde nous avons exploré la combinatoire de la signalisation cellulaire en développant un formalisme discret basé sur les transitions gardées. Cette approche regroupe l'interprétation de la base de données Pathway Interaction Database dans un unique modèle dynamique de propagation du signal. Des méthodes de simulations et d'analyses inspirées des techniques de vérification de modèles telles que l'atteignabilité et l'invariance ont été développées. En outre, nous avons étudié la régulation du cycle cellulaire en réponse à la signalisation, ainsi que la régulation des gènes de notre modèle en comparaison avec des données d'expressions.
https://tel.archives-ouvertes.fr/tel-00926487

Droits : info:eu-repo/semantics/OpenAccess
tel-00926487
https://tel.archives-ouvertes.fr/tel-00926487
https://tel.archives-ouvertes.fr/tel-00926487/document
https://tel.archives-ouvertes.fr/tel-00926487/file/AndrieuxThese.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Geochronological studies of samples from continuous crustal sections of fossil intra-oceanic arcs are paramount for determining the precise timing of major processes that took place during the building of an oceanic island-arc crust. In this study, laser ablation ICP-MS U-Pb zircon (and conventional Rb-Sr) analyses pinpoint the timing of major events responsible for crustal growth of the Kohistan paleo-island arc (Northern Pakistan). Inheritance in magmatic rocks is evidence for recycling of intra-arc material and indicates that the Kohistan arc may have formed as early as 135 +/- 4 Ma. One older inherited grain indicates that the arc developed on a young oceanic lithosphere whose remnants include a c. 175 Ma old component. An interesting consequence is that intra-oceanic arc magmas can yield inherited zircons, which can be much older than the arc system itself without requiring recycling back into the mantle by subduction processes. In the case of the Kohistan arc, ante-arc Neotethys oceanic lithosphere was tapped by arc magmas during their way upward into the arc crust. The oldest magmatic ages measured in this study fall in the range 101-102 Ma (100.9 +/- 0.6 and 102.1 +/- 0.4 Ma). This period corresponds to arc build-up and thickening of the arc crust. Leucogranitic melts dated at 89.9 +/- 0.4 Ma and 90.9 +/- 1.0 Ma are considered as produced by dehydration/melting reaction accompanying granulitisation of the thickened lower arc crust. A maximum age for this event is 97.7 +/- 0.7 Ma, the age of emplacement of a garnet meta-tonalite affected by granulite facies metamorphism. Magmatic activity was still ongoing during and after the granulitisation as testified by emplacement of a diorite and a gabbro dated at 89.1 +/- 0.6 and 88.2 +/- 0.9 Ma respectively. The upper part of the metaplutonic sequence contains diorite samples dated at 84.6 +/- 0.5 Ma and 84.3 +/- 0.5 Ma and as young as 81.1 +/- 0.7 Ma. During this period, and based on the present day outcropping sequences, the mean crustal growth rate varied from 32 to 65 km(3)/km/Ma (volume per unit width along the strike of the arc) which is comparable to the range for present day arcs of the Western Pacific region. The correspondence of crustal growth rates observed for present-day island arcs and the good preservation of the crustal section in the Kohistan arc, make this area an exceptional natural laboratory to study arc related processes and to check models of continental crust formation by arc accretion.
ISSN: 0012-821X

hal-00644555
https://hal.archives-ouvertes.fr/hal-00644555
DOI : 10.1016/j.epsl.2011.07.016

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
BACKGROUND: Although adverse birth outcomes have been associated with neighbourhood deprivation in urban areas, few studies have addressed this issue in rural zones. This study examines whether associations between neighbourhood deprivation and adverse birth outcomes differ in urban and rural contexts, while taking individual characteristics and spatial accessibility of prenatal care (SAPC) into account. METHODS: Pregnant women from a French mother-child cohort were recruited from 2002 to 2006 in Brittany. Their residential addresses were geocoded into their census blocks (the finest geographical resolution available). Deprivation was assessed at the same neighbourhood level. Models to assess the associations of deprivation, stratified by urban/rural status, with preterm delivery (PTD), with small for gestational age birth weight (SGA) and with small for gestational age head circumference at birth (SHC), estimated odds ratios (ORs), adjusted for maternal socioeconomic characteristics and SAPC. RESULTS: This study considered 2929 liveborn singleton pregnancies from 780 census blocks. Neighbourhood deprivation was associated with increased risks of SGA and SHC (P trend  extless 0.01 and 0.03 respectively), only among mothers residing in rural areas. Neighbourhood deprivation had statistically significantly heterogeneous effects on SGA and SHC according to the urban/rural status of maternal residence. CONCLUSION: These findings suggest that neighbourhood deprivation affects fetal growth differentially in urban and rural areas and that SAPC does not seem to be responsible for this difference. Comparison of these findings with the literature requires caution in the conceptualisation of urban and rural settings
ISSN: 0269-5022

hal-01187424
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187424
DOI : 10.1111/ppe.12208
PUBMED : 26186278

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Gravitropism is necessary for plants to control the orientation of their axes while they grow in height. In woody plants, stem re-orientations are costly because they are achieved through diameter growth. The functional diversity of gravitropism was studied to check if the mechanisms involved and their efficiency may contribute to the differentiation of height growth strategies between forest tree species at the seedling stage. Seedlings of eight tropical species were grown tilted in a greenhouse, and their up-righting movement and diameter growth were measured during three months. Morphological, anatomical and biomechanical traits were measured at the end of the survey. Curvature analysis was used to analyse the up-righting response along the stems. Variations in stem curvature depend on diameter growth, size effects, the increase in self-weight, and the efficiency of the gravitropic reaction. A biomechanical model was used to separate these contributions. Results showed that (1) gravitropic movements were based on a common mechanism associated to similar dynamic patterns, (2) clear differences in efficiency (defined as the change in curvature achieved during an elementary diameter increment for a given stem diameter) existed between species, (3) the equilibrium angle of the stem and the anatomical characters associated to the efficiency of the reaction also differed between species, (4) the differences in gravitropic reaction were related to the light requirements: heliophilic species, compared to more shade-tolerant species, had a larger efficiency and an equilibrium angle closer to vertical. This suggests that traits determining the gravitropic reaction are related to the strategy of light interception and may contribute to the differentiation of ecological strategies promoting the maintenance of biodiversity in tropical rain forests.
ISSN: 0022-0957

hal-00797023
https://hal.archives-ouvertes.fr/hal-00797023
https://hal.archives-ouvertes.fr/hal-00797023/document
https://hal.archives-ouvertes.fr/hal-00797023/file/Functional_diversity_gravitropic_Almeras_al.pdf