852 research outputs found
Faut-il avoir peur de lâapproche Ă©conomique de la biodiversitĂ© et des services rendus par les Ă©cosystĂšmes ?
Cet article vise Ă prĂ©ciser les enjeux de lâĂ©valuation Ă©conomique de la biodiversitĂ© et des services Ă©cosystĂ©miques pour en clarifier les intĂ©rĂȘts, les limites et le contexte dans lequel elle peut ĂȘtre utilisĂ©e. Pour cela, nous rappelons succinctement ce qui fonde lâimportance sociale de la biodiversitĂ©, afin de prĂ©ciser les enjeux dâune Ă©valuation Ă partir des services Ă©cosystĂ©miques. Nous rappelons la prise de conscience ayant eu lieu dĂšs la fin du XXe siĂšcle, dâune Nature jouant un rĂŽle majeur dans notre bien-ĂȘtre, mais Ă©galement dâune pression croissante exercĂ©e sur elle favorisant son Ă©rosion. Ceci incite lâĂ©conomie Ă la considĂ©rer comme un « capital naturel » non infini nĂ©cessitant dâĂȘtre gĂ©rĂ© au mĂȘme titre que dâautres ressources. Nous prĂ©cisons ensuite la signification de lâĂ©valuation Ă©conomique et les enjeux de son Ă©largissement aux actifs non marchands dans le cadre de la valeur Ă©conomique totale. Enfin, avant dâexposer les limites de lâapproche, nous revenons sur les techniques dâĂ©valuation pour mieux comprendre pourquoi elles restent controversĂ©es
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 ParĂs ; MĂĄrgenes graduados.Escala grĂĄfica ademĂĄs en 'Grandes lieves de 25 au DegrĂ©s'
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 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 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
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 vineâ1 (5.3 mm) prior to turning the pump off, and it decreased to 22.3 L vineâ1 by September 2nd. Pre-dawn leaf water potential (ΚPD) and midday Κl on August 24th were â0.075 and â0.76 MPa, respectively, with midday Κl decreasing to â1.28 MPa on September 2nd. Leaf g s decreased from ~500 to ~200 mmol mâ2 sâ1 during the two dry-down periods. Midday measurements of g s and Κl were significantly correlated with one another (r = 0.96) and both with ETLYS/ETo (r = ~0.9). The decreases in Κl, 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
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