Faut-il avoir peur de l’approche économique de la biodiversité et des services rendus par les écosystèmes ?

Cet article vise à préciser les enjeux de l’évaluation économique de la biodiversité et des services écosystémiques pour en clarifier les intérêts, les limites et le contexte dans lequel elle peut être utilisée. Pour cela, nous rappelons succinctement ce qui fonde l’importance sociale de la biodiversité, afin de préciser les enjeux d’une évaluation à partir des services écosystémiques. Nous rappelons la prise de conscience ayant eu lieu dès la fin du XXe siècle, d’une Nature jouant un rôle majeur dans notre bien-être, mais également d’une pression croissante exercée sur elle favorisant son érosion. Ceci incite l’économie à la considérer comme un « capital naturel » non infini nécessitant d’être géré au même titre que d’autres ressources. Nous précisons ensuite la signification de l’évaluation économique et les enjeux de son élargissement aux actifs non marchands dans le cadre de la valeur économique totale. Enfin, avant d’exposer les limites de l’approche, nous revenons sur les techniques d’évaluation pour mieux comprendre pourquoi elles restent controversées

Vegetative growth and water use characterization of a maize introgression library

Previous work showed that a maize introgression library (IL) derived from the cross between Gasp\ue9 Flint (an early flowering Canadian landrace) and B73 (the reference maize line) segregated for phenology as well for seminal root architecture (SRA) traits. In this experiment, the IL was evaluated in the high-throughput phenotyping platform PhenoArch (INRA, Montpellier

A geospatial model of nature-based recreation for urban planning: case study of Paris, France

Environmental Biolog

LEMOSIN (Francia). Mapas generales (1797). 1:252525

Indica meridianos de origen: Isla del Hierro y París ; Márgenes graduados.Escala gráfica además en 'Grandes lieves de 25 au Degrés'

Theory of Cylindrical Tubules and Helical Ribbons of Chiral Lipid Membranes

We present a general theory for the equilibrium structure of cylindrical tubules and helical ribbons of chiral lipid membranes. This theory is based on a continuum elastic free energy that permits variations in the direction of molecular tilt and in the curvature of the membrane. The theory shows that the formation of tubules and helical ribbons is driven by the chirality of the membrane. Tubules have a first-order transition from a uniform state to a helically modulated state, with periodic stripes in the tilt direction and ripples in the curvature. Helical ribbons can be stable structures, or they can be unstable intermediate states in the formation of tubules.Comment: 43 pages, including 12 postscript figures, uses REVTeX 3.0 and epsf.st

Non-monotonic variation with salt concentration of the second virial coefficient in protein solutions

The osmotic virial coefficient $B_2$ of globular protein solutions is calculated as a function of added salt concentration at fixed pH by computer simulations of the ``primitive model''. The salt and counter-ions as well as a discrete charge pattern on the protein surface are explicitly incorporated. For parameters roughly corresponding to lysozyme, we find that $B_2$ first decreases with added salt concentration up to a threshold concentration, then increases to a maximum, and then decreases again upon further raising the ionic strength. Our studies demonstrate that the existence of a discrete charge pattern on the protein surface profoundly influences the effective interactions and that non-linear Poisson Boltzmann and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory fail for large ionic strength. The observed non-monotonicity of $B_2$ is compared to experiments. Implications for protein crystallization are discussed.Comment: 43 pages, including 17 figure

Midday measurements of leaf water potential and stomatal conductance are highly correlated with daily water use of Thompson Seedless grapevines

A study was conducted to determine the relationship between midday measurements of vine water status and daily water use of grapevines measured with a weighing lysimeter. Water applications to the vines were terminated on August 24th for 9 days and again on September 14th for 22 days. Daily water use of the vines in the lysimeter (ETLYS) was approximately 40 L vine−1 (5.3 mm) prior to turning the pump off, and it decreased to 22.3 L vine−1 by September 2nd. Pre-dawn leaf water potential (ΨPD) and midday Ψl on August 24th were −0.075 and −0.76 MPa, respectively, with midday Ψl decreasing to −1.28 MPa on September 2nd. Leaf g s decreased from ~500 to ~200 mmol m−2 s−1 during the two dry-down periods. Midday measurements of g s and Ψl were significantly correlated with one another (r = 0.96) and both with ETLYS/ETo (r = ~0.9). The decreases in Ψl, g s, and ETLYS/ETo in this study were also a linear function of the decrease in volumetric soil water content. The results indicate that even modest water stress can greatly reduce grapevine water use and that short-term measures of vine water status taken at midday are a reflection of daily grapevine water us

Evo-devo of human adolescence: beyond disease models of early puberty

Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research