309 research outputs found
Histoire de l'Academie Royale de Sciences : année MDCCXXII, avec les Memoires de Mathematique & de Physique, pour la même Année, tirés des registres de cette Académie.
No full textSign.: []\p1\s, a\p4\s, A-S\p4\s, T, A-3A\p4\s, 3B\p2\s.Port. con grab. xil.Las h. de grab. calc.:"Simonneau filius sculp.", "Ph. Simonneau Sculp."Front. calc.: ¨Ant. Coypel pinxit. Carol. Dupuis sculp 1719¨
The significance of roots as hydraulic rheostats
No full textRoots are the primary sites of water uptake by plants. Roots also sense most of the physico-chemical parameters of the soil, perceive signals from the shoots, and adjust their growth and water transport properties accordingly. The present opinion paper discusses the significance of the variable water transport capacity (hydraulic conductance) of roots during development and in response to environmental stimuli. It is shown that root hydraulics determines water uptake intensities but also water potential gradients within the plant. It is indicated how the dynamics of root hydraulics contributes to many integrated plant nutritional and growth functions. For instance, the heterogeneity of soil water and nutrient availability and the heterogeneity of root hydraulic properties feed each other and play critical roles in root transport functions. Another important aspect is the integration of root hydraulics within the mutual interactions of roots and shoots, for co-ordinated growth and water-saving responses to drought.Fil: Maurel, Christophe. Universite Montpellier II; FranciaFil: Simonneau, Thierry. Universite Montpellier II; FranciaFil: Sutka, Moira Romina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universite Montpellier II; Franci
Histoire de l'Academie Royale des Sciences : année MDCCXXV, avec les Mémoires de Mathématique & de Physique, pour la même Année, tirés des registres de cette Académie.
No full textSign.: a\p4\s, A-T\p4\s, V\p1\s, A-2X\p4\s, 2Y\p2\s.Port. con grab. xil.Las h. de grab. pleg. calc.: "Ph. Simonneau filius sculp."Front. calc.: ¨Ant. Coypel Eques pinxil. Carol. Dupuis sculp 1719¨
Pläne und Ansichten / 20 Partie du duché de Milan, la principauté de Piémont, le Montferrat; et la republi.que de Genes : dedié au roy
No full textpar son tres-humb', tres-obeissa[n]t, tres-fidele sujet et serviteur Hubert Iaillot ; [Titelkartusche:] S[imonneau] f[ecit]"avec privilege de S. Maj.té
Structural properties of disk galaxies. II. Intrinsic shape of bulges
No full textContext: Knowledge of the intrinsic shapes of galaxy components provides crucial information when constraining phenomena driving their formation and evolution. Aims: We analize the structural parameters of a magnitude-limited sample of 148 unbarred S0-Sb galaxies to derive the intrinsic shape of their bulges. Methods: We developed a new method to derive the intrinsic shapes of bulges based on geometrical relationships between the apparent and intrinsic shapes of bulges and disks. Bulges were assumed to be triaxial ellipsoids sharing the same center and polar axis of their surrounding disks. Disks were assumed to be circular, infinitesimally thin, and to lie on the equatorial plane of bulges. The equatorial ellipticity and intrinsic flattening of bulges were obtained from the length of the apparent major and minor semi-axes of the bulge, the twist angle between the apparent major axis of the bulge and the galaxy line of nodes, and the galaxy inclination. Results: We find that the intrinsic shape is well constrained for a subsample of 115 bulges with favorable viewing angles. A large fraction of them are characterized by an elliptical section (B/A 50% and none has a probability > 90% of being elongated along the polar axis. The distribution of triaxiality is strongly bimodal. This bimodality is driven by bulges with Sérsic index n > 2, or equivalently, by the bulges of galaxies with a bulge-to-total ratio B/T > 0.3. Bulges with n ≤ 2 and with B/T ≤ 0.3 follow a similar distribution, which differs from that of bulges with n > 2 and B/T > 0.3. In particular, bulges with n ≤ 2 and B/T ≤ 0.3 exhibit a larger fraction of oblate axisymmetric (or nearly axisymmetric) bulges, a smaller fraction of triaxial bulges, and fewer prolate axisymmetric (or nearly axisymmetric) bulges with respect to bulges with n > 2 and with B/T > 0.3, respectively. No correlation is found between the intrinsic shape and either the luminosity or velocity dispersion of bulges. Conclusions: According to predictions of the numerical simulations of bulge formation, bulges with n ≤ 2, which show a high fraction of oblate axisymmetric (or nearly axisymmetric) shapes and have B/T ≤ 0.3, may be the result of dissipational minor mergers. Both major dissipational and dissipationless mergers seem to be required to explain the variety of shapes found for bulges with n > 2 and B/T > 0.3
Que reste-t-il des réformes de la gestion urbaine ? Mémoire du développement et instruments d’action publique
No full textInternational audienc
A leaf gas exchange model that accounts for intra‐canopy variability by considering leaf nitrogen content and local acclimation to radiation in grapevine (Vitis vinifera L.)
No full textUnderstanding the distribution of gas exchange within a plant is a prerequisite for scaling up from leaves to canopies. We evaluated whether leaf traits were reliable predictors of the effects of leaf ageing and leaf irradiance on leaf photosynthetic capacity (Vcmax, Jmax) in field‐grown vines (Vitis vinifera L). Simultaneously, we measured gas exchange, leaf mass per area (LMA) and nitrogen content (Nm) of leaves at different positions within the canopy and at different phenological stages. Daily mean leaf irradiance cumulated over 10 d (PPFD10) was obtained by 3D modelling of the canopy structure. Nm decreased over the season in parallel to leaf ageing while LMA was mainly affected by leaf position. PPFD10 explained 66, 28 and 73% of the variation of LMA, Nm and nitrogen content per area (Na), respectively. Nitrogen content per unit area (Na=LMA×Nm) was the best predictor of the intra‐canopy variability of leaf photosynthetic capacity. Finally, we developed a classical photosynthesis‐stomatal conductance submodel and by introducing Na as an input, the model accurately simulated the daily pattern of gas exchange for leaves at different positions in the canopy and at different phenological stages during the season.EEA MendozaFil: Prieto, Jorge Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Institut National de la Recherche Agronomique; FranciaFil: Louarn, Gaëtan. Institut National de la Recherche Agronomique; FranciaFil: Perez Peña, Jorge Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Ojeda, Hernan. Institut National de la Recherche Agronomique. Unité expérimentale de Pech Rouge; FranciaFil: Simonneau, Thierry. Institut National de la Recherche Agronomique; FranciaFil: Lebon, Eric. Institut National de la Recherche Agronomique. Unité Mixte de Recherche; Franci
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