473 research outputs found

    Définitions des ressources naturelles et implications pour la démarche juridique

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    Contribution publiĂ©e in Penser une dĂ©mocratie alimentaire Volume II – Proposition Lascaux entre ressources naturelles et besoins fondamentaux, F. Collart Dutilleul et T. BrĂ©ger (dir), Inida, San JosĂ©, 2014, pp. 71-77International audienceLa construction d’un droit dĂ©diĂ© aux ressources naturelles nĂ©cessite de s’accorder prĂ©alablement sur les notions clĂ©s. A cet Ă©gard, les choix effectuĂ©s ne seront pas indiffĂ©rents ou dĂ©pourvus de consĂ©quences : ils reflĂštent les valeurs considĂ©rĂ©es comme fondamentales dans nos sociĂ©tĂ©s. Bien que les choix de vocabulaire soient essentiellement des choix politiques, nous soutenons que le concept lĂ©gal de « ressources naturelles » devrait satisfaire aux objectifs de maintien des systĂšmes supportant la vie sur Terre et de satisfaction des besoins fondamentaux humains

    Testing the recent theories for the origin of the hermaphrodite flower by comparison of the transcriptomes of gymnosperms and angiosperms

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    <p>Abstract</p> <p>Background</p> <p>Different theories for the origin of the angiosperm hermaphrodite flower make different predictions concerning the overlap between the genes expressed in the male and female cones of gymnosperms and the genes expressed in the hermaphrodite flower of angiosperms. The Mostly Male (MM) theory predicts that, of genes expressed primarily in male versus female gymnosperm cones, an excess of male orthologs will be expressed in flowers, excluding ovules, while Out Of Male (OOM) and Out Of Female (OOF) theories predict no such excess.</p> <p>Results</p> <p>In this paper, we tested these predictions by comparing the transcriptomes of three gymnosperms (<it>Ginkgo biloba</it>, <it>Welwitschia mirabilis </it>and <it>Zamia fisheri</it>) and two angiosperms (<it>Arabidopsis thaliana </it>and <it>Oryza sativa</it>), using EST data. We found that the proportion of orthologous genes expressed in the reproductive organs of the gymnosperms and in the angiosperms flower is significantly higher than the proportion of orthologous genes expressed in the reproductive organs of the gymnosperms and in the angiosperms vegetative tissues, which shows that the approach is correct. However, we detected no significant differences between the proportion of gymnosperm orthologous genes expressed in the male cone and in the angiosperms flower and the proportion of gymnosperm orthologous genes expressed in the female cone and in the angiosperms flower.</p> <p>Conclusions</p> <p>These results do not support the MM theory prediction of an excess of male gymnosperm genes expressed in the hermaphrodite flower of the angiosperms and seem to support the OOM/OOF theories. However, other explanations can be given for the 1:1 ratio that we found. More abundant and more specific (namely carpel and ovule) expression data should be produced in order to further test these theories.</p

    A Natural Resource-Systems approach: Targeting the Ecological Transition at the Regional Scale

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    Chapitre de l’ouvrage collectif Penser une dĂ©mocratie alimentaire Volume II – Proposition Lascaux entre ressources naturelles et besoins fondamentaux, F. Collart Dutilleul et T. BrĂ©ger (dir), Inida, San JosĂ©, 2014, pp. 143-167.International audienceHuman history can be mirrored in a geo-history of natural resources. Humans, by over-exploiting resources (“forcing”), have produced extensive land use changes and have altered complex food webs, ecosystems, and habitats with as a consequence systematic natural biocapacity erosion, biodiversity loss, energy crises, pollution, climate deregulation. In other terms, a global resources “rush” has led to chronic socio-ecosystemic deficits, thus creating the conditions for local and global state shifts within the biosphere and / or society.Therefore, research must serve to increase human understanding of those resources and how best to use them for the public good

    A gradual process of recombination restriction in the evolutionary history of the sex chromosomes in dioecious plants.

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    To help understand the evolution of suppressed recombination between sex chromosomes, and its consequences for evolution of the sequences of Y-linked genes, we have studied four X-Y gene pairs, including one gene not previously characterized, in plants in a group of closely related dioecious species of Silene which have an X-Y sex-determining system (S. latifolia, S. dioica, and S. diclinis). We used the X-linked copies to build a genetic map of the X chromosomes, with a marker in the pseudoautosomal region (PAR) to orient the map. The map covers a large part of the X chromosomes--at least 50 centimorgans. Except for a recent rearrangement in S. dioica, the gene order is the same in the X chromosomes of all three species. Silent site divergence between the DNA sequences of the X and Y copies of the different genes increases with the genes' distances from the PAR, suggesting progressive restriction of recombination between the X and Y chromosomes. This was confirmed by phylogenetic analyses of the four genes, which also revealed that the least-diverged X-Y pair could have ceased recombining independently in the dioecious species after their split. Analysis of amino acid replacements vs. synonymous changes showed that, with one possible exception, the Y-linked copies appear to be functional in all three species, but there are nevertheless some signs of degenerative processes affecting the genes that have been Y-linked for the longest times. Although the X-Y system evolved quite recently in Silene (less than 10 million years ago) compared to mammals (about 320 million years ago), our results suggest that similar processes have been at work in the evolution of sex chromosomes in plants and mammals, and shed some light on the molecular mechanisms suppressing recombination between X and Y chromosomes

    The Influence of Age, Location and Soil Conditions on the Allometry of Young Norway Spruce (Picea abies L. Karst.) Trees

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    In this study the influence of tree’s age, location (i.e. latitude and altitude) and soil conditions (i.e. pH, humus content, carbon to nitrogen ratio, cation exchange capacity and percent base saturation) on tree allometry was investigated. The data was collected from 22 Norway spruce (Picea abies L. Karst) plantations located in Eastern Carpathians of Romania, aged between 4 and 15. From each plantation a soil sample and 10 trees were collected for soil chemical properties and biomass measurements, respectively. Root collar diameter (RCD) and height (H) based allometric equations were developed for total tree and vegetative organs of the tree (i.e. stem, branches, needles and roots). Furthermore, the interaction between the standardised residuals of these models and the tested factors was analysed. In order to account for the random effect of the clustered data, the mixed-effect modelling procedure was used. The results have shown no influence of these factors (age, location and soil conditions) on RCD based models, except for branches biomass model which was linked to soil carbon/nitrogen ratio. The H based models, however, were significantly influenced by latitude and soil cation exchange capacity as a consequence of H/RCD ratio change with these factors. The trees were more likely to allocate more to height growth when growing in higher latitudes or on soils with higher values of cation exchange capacity

    Effects of Temperature Variations during Sintering of Metal Ceramic Tooth Prostheses Investigated Non-Destructively with Optical Coherence Tomography

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    Calibration loss of ovens used in sintering metal ceramic prostheses leads to stress and 18 cracks in the material of the prostheses fabricated, and ultimately to failure of the dental treatment. 19 Periodic calibration may not be sufficient to prevent such consequences. Evaluation methods based 20 on firing supplemental control samples are subjective, time consuming, and rely entirely on the 21 technician’s skills. The aim of this study was to propose an alternative procedure for such 22 evaluations. Fifty prostheses were sintered in a ceramic oven at a temperature lower, equal or 23 larger than the temperature prescribed by the manufacturer. A non-destructive imaging method, 24 swept source (SS) optical coherence tomography (OCT) was used to evaluate comparatively the 25 internal structure of prostheses so fabricated. A quantitative assessment procedure is proposed, 26 based on en-face OCT images acquired at similar depths inside the samples. Differences in 27 granulation and reflectivity depending on the oven temperature are used to establish 28 rules-of-thumb on judging the correct calibration of the oven. OCT evaluations, made on a regular 29 basis allow an easy and objective monitoring of correct settings in the sintering process. This 30 method can serve rapid identificatio

    Effects of Temperature Variations during Sintering of Metal Ceramic Tooth Prostheses Investigated Non-Destructively with Optical Coherence Tomography

    Get PDF
    Calibration loss of ovens used in sintering metal ceramic prostheses leads to stress and 18 cracks in the material of the prostheses fabricated, and ultimately to failure of the dental treatment. 19 Periodic calibration may not be sufficient to prevent such consequences. Evaluation methods based 20 on firing supplemental control samples are subjective, time consuming, and rely entirely on the 21 technician’s skills. The aim of this study was to propose an alternative procedure for such 22 evaluations. Fifty prostheses were sintered in a ceramic oven at a temperature lower, equal or 23 larger than the temperature prescribed by the manufacturer. A non-destructive imaging method, 24 swept source (SS) optical coherence tomography (OCT) was used to evaluate comparatively the 25 internal structure of prostheses so fabricated. A quantitative assessment procedure is proposed, 26 based on en-face OCT images acquired at similar depths inside the samples. Differences in 27 granulation and reflectivity depending on the oven temperature are used to establish 28 rules-of-thumb on judging the correct calibration of the oven. OCT evaluations, made on a regular 29 basis allow an easy and objective monitoring of correct settings in the sintering process. This 30 method can serve rapid identificatio
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