L'adaptation au changement climatique dans le bassin de Tensift au Maroc par une gestion améliorée du bassin versant et le paiement pour les services environnementaux - rapport final

Ce projet bénéficie d'une subvention du Centre de recherches pour le développement international (CRDI), Ottawa, Canada.Le défi que le présent projet de recherche a essayé de relever est de trouver des pistes pour repenser la GIRE dans un contexte du changement climatique, tout en prenant en considération le maintien de la production des biens et services environnementaux. Ceci ne pourra se réaliser qu’à travers des actions permettant de prendre en considération la donne climatique et les instruments basés sur le marché (e.g. le Paiement pour les Services Environnementaux (PSE)) dans les politiques de gestion de l’eau

Variations of Plasmid Content in Rickettsia felis

Background: Since its first detection, characterization of R. felis has been a matter of debate, mostly due to the contamination of an initial R. felis culture by R. typhi. However, the first stable culture of R. felis allowed its precise phenotypic and genotypic characterization, and demonstrated that this species belonged to the spotted fever group rickettsiae. Later, its genome sequence revealed the presence of two forms of the same plasmid, physically confirmed by biological data. In a recent article, Gillespie et al. ( PLoS One. 2007; 2( 3): e266.) used a bioinformatic approach to refute the presence of the second plasmid form, and proposed the creation of a specific phylogenetic group for R. felis. Methodology/ Principal Findings: In the present report, we, and five independent international laboratories confirmed unambiguously by PCR the presence of two plasmid forms in R. felis strain URRWXCal(2)(T), but observed that the plasmid content of this species, from none to 2 plasmid forms, may depend on the culture passage history of the studied strain. We also demonstrated that R. felis does not cultivate in Vero cells at 37 degrees C but generates plaques at 30 degrees C. Finally, using a phylogenetic study based on 667 concatenated core genes, we demonstrated the position of R. felis within the spotted fever group. Significance: We demonstrated that R. felis, which unambiguously belongs to the spotted fever group rickettsiae, may contain up to two plasmid forms but this plasmid content is unstable

Modélisation par un mannequin thermique des pertes de chaleur évaporatoire d'un nouveau-né dans un incubateur fermé (validation et applications biomédicales)

Afin de quantifier les échanges de chaleur entre le nouveau-né placé dans un incubateur et son environnement et en particulier les pertes d eau transcutanées, nous avons conçu un mannequin sueur représentatif de l anatomie d un nouveau-né de 900 g. Il s agit donc de réaliser un mannequin en cuivre avec une surface à partir de laquelle on peut réaliser une évaporation de l eau. Ce système est donc capable de simuler et caractériser les échanges de chaleur sèche définis par la conduction, la convection et le rayonnement, et l échange de chaleur latente à savoir l évaporation. L originalité de ce modèle ; il permet de simuler sur chaque membre une mouillure cutanée susceptible d être différente de celle des autres membres, ce qui permet de simuler la mouillure qui peut exister chez les nouveau-nés. Il permet aussi d éviter la variabilité interindividuelle qui est particulièrement importante chez les enfants prématurés ainsi que les contraintes éthiques. Le modèle mannequin a permis de calculer différents paramètres indispensables à la gestion de l environnement thermique dans les incubateurs en particulier ceux liés aux pertes évaporatoires. Ceci a permis d évaluer la chaleur latente d évaporation et le coefficient d échange de chaleur par évaporation dont la mesure est complexe. La comparaison des résultats obtenus avec les valeurs rapportées par d autres auteurs permet de conclure sur la fiabilité des résultats et aussi sur l utilisation de notre mannequin comme référence. Le modèle a également permis de répondre à des préoccupations médicales consistant à vérifier l effet de la position de couchage dorsale ou ventrale sur les échanges de chaleur et l efficacité d un sac de polyéthylène sur les pertes en eau et sur les échanges de chaleur d un nouveau-né prématuré dans les premières jours de vie.AMIENS-BU Santé (800212102) / SudocSudocFranceF

Influence of neonate's body position with and without a plastic blanket on body heat loss assessed from a thermal mannequin

International audienceThe present study aimed at assessing the net gain of body heat storage induced by a transparent plastic blanket draped over small premature neonates in the prone and the supine positions. Thermal stress is particularly important in premature and small-for-gestational-age infants characterized by high values of the ratio between skin surface area and body mass, the greater this ratio, the greater the body heat exchanges. The large skin permeability enhances body water loss. The risk of hypothermia is particularly increased at birth and during operations on naked neonates implying opening of the canopy (surgical operation, blood sampling and gastric aspiration). In the first day of life, the rate of evaporation can reach 100 g.h-1.m-2 in very preterm infants. To prevent the large amount of water loss it is sometimes recommended to cover the neonate with a plastic blanket. In closed incubator Fanaroff et al.(3) pointed out that a transparent plastic heat shield reduces the insensible water loss of 44 % in low birth weight neonates lower than 1250 g and postnatal age less than 10 days. For postnatal age greater than 10 days, the magnitude of this reduction was only 19 %. Bell et al.(2) also reported that the addition of a heat shield in an incubator decreased the water loss by 10 % in infants with mean birth weight of 1570 g. However the efficiency of this solution which depends on the physical environment but also on the inter individual difference in the ability to exchange heat with the environment remains questionable and the use of a plastic blanket is still a controversial topic. The total heat loss of premature infants depends on various factors such as gestational age, nutritional state, mean skin temperature, body hydromineral balance, vigilance state, metabolic rate and of the postnatal age which modifies the skin keratinisation. Thus, it is difficult to obtain homogeneous data base that takes into account all these factors and there are conflicting data on the effectiveness of plastic blanket. To rule out these confounding factors we use a sweating mannequin the advantage of which is that it measures directly the total heat loss with the environment without interference with these factors

Assessment of whole body and regional evaporative heat loss coefficients in very premature infants using a thermal mannequin : influence of air velocity

International audienceIn human adults, experimental assessment of the evaporative heat loss coefficient (he) requires a fully wetted skin surface area implying exposure to severe heat stress. For ethical reasons, this type of experimental situation is impossible to perform on neonates. The aim of the present study was to assess he values in clinical situations for the body as a whole and for the different body segments, in particular, in natural and forced convection and using an anthropomorphic, sweating, thermal mannequin to represent a very small premature neonate (body mass 900 g). Skin hydration (i.e., simulated sweating) was performed by two electronic pumping systems, providing a steady adjustable flow of water to the mannequin surface. Experiments were carried out in a closed-incubator heated to air temperatures of 33 degrees C and 36 degrees C, with air velocities (V,) ranging from 0.01 to 0.7 m s(-1), and with four levels of air relative humidity (40, 50, 60, and 80%). For the body as a whole, h(e) = 7 W m(-2) mb(-1) in natural convection, whereas in forced convection h(e) was 11.7, 12.4, and 14.1 W m(-2) mb(-1) for air velocities of 0.2, 0.4, and 0.7 m s(-1), respectively. As far as local he is concerned, our results showed that the relative values of regional water loss in forced convection differ greatly from those observed under still air conditions. Thus, increasing air velocity enhances the heterogeneity in regional skin cooling, which may contribute to the neonate's thermal discomfort

Phylogenetic tree inferred from the comparison of 667 concatenated <i>Rickettsia</i> core protein-coding genes using the maximum parsimony method.

<p>Bootstrap values are indicated at branch nodes. A similar topology was obtained using the Neighbor-Joining analysis method.</p

Determination of the <i>R. felis</i> plasmid ratio.

<p>The Southern blot obtained by hybridizing <i>R. felis</i> genomic DNA digested with PvuI and resolved by PFGE with probes specific for each plasmid form <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002289#pone.0002289-Ogata1" target="_blank">[18]</a> was digitalized by transmission scanning (ImageScanner, Amersham Biosciences). The quantification of each labelled plasmid band was estimated by analysis with the ImageMaster 2D Platinium Version 6.0 software (Amersham Biosciences). The pRF and pRFδ spots represented 57% and 43%, respectively, of the hybridization intensity.</p