Effets du suivi zootechnique sur les performances de production et la rentabilité des élevages de bovins laitiers en périmètre irrigué au Maroc

International audienceUne démarche de " suivi - intervention " a été adoptée dans cinq exploitations agricoles, illustrant la diversité des situations d'élevage bovin laitier dans le périmètre irrigué du Tadla (Maroc). Un diagnostic initial de gestion de l'élevage (alimentation et reproduction) et de ses répercussions sur la productivité et la rentabilité des troupeaux bovins a été réalisé dans chaque étable. Des manques à gagner ayant été détectés, un appui technique en continu a été instauré. Il a consisté en l'évaluation des carences alimentaires dans les rations utilisées par les éleveurs et en leur correction par des matières premières disponibles (plus de fourrages ou recours aux concentrés). Les résultats ont montré qu'en dépit de la conjoncture climatique difficile où s'est déroulé ce travail (campagne agricole de 2006-2007 où les précipitations ont été de 200 mm par rapport à une moyenne annuelle de 300 mm sur les dix dernières années), l'encadrement alimentaire rapproché a permis de promouvoir le rendement laitier des vaches, par l'extériorisation de leur potentiel génétique. L'étude a aussi révélé que les vaches de race Holstein affichaient de meilleures réponses au rationnement alimentaire par rapport aux vaches de type croisé, en raison de leurs aptitudes laitières plus affirmées. Les résultats ont indiqué que l'appui technique permettait l'augmentation des livraisons de lait par vache et la diminution du prix de revient du lait. Étant donné le contexte actuel de désengagement prononcé des services techniques de l'Etat de l'encadrement de la production agricole, la méthode d'appui zootechnique mise à l'épreuve dans ce suivi gagnerait à être prise en main par les associations professionnelles et les coopératives de collecte du lait pour être diffusée auprès d'un effectif plus important, en vue d'en juger l'impact sur toute la filière dans le périmètre irrigué du Tadla

Genomic Organization and Expression of Iron Metabolism Genes in the Emerging Pathogenic Mold

The ubiquitous mold is increasingly recognized as an emerging pathogen, especially among patients with underlying disorders such as immunodeficiency or cystic fibrosis (CF). Indeed, it ranks the second among the filamentous fungi colonizing the respiratory tract of CF patients. However, our knowledge about virulence factors of this fungus is still limited. The role of iron-uptake systems may be critical for establishment of infections, notably in the iron-rich environment of the CF lung. Two main strategies are employed by fungi to efficiently acquire iron from their host or from their ecological niche: siderophore production and reductive iron assimilation (RIA) systems. The aim of this study was to assess the existence of orthologous genes involved in iron metabolism in the recently sequenced genome of . At first, a tBLASTn analysis using iron-related proteins as query revealed orthologs of almost all relevant loci in the genome. Whereas the genes putatively involved in RIA were randomly distributed, siderophore biosynthesis and transport genes were organized in two clusters, each containing a non-ribosomal peptide synthetase (NRPS) whose orthologs in have been described to catalyze hydroxamate siderophore synthesis. Nevertheless, comparative genomic analysis of siderophore-related clusters showed greater similarity between and phylogenetically close molds than with species. The expression level of these genes was then evaluated by exposing conidia to iron starvation and iron excess. The expression of several orthologs of genes involved in siderophore-based iron uptake or RIA was significantly induced during iron starvation, and conversely repressed in iron excess conditions. Altogether, these results indicate that possesses the genetic information required for efficient and competitive iron uptake. They also suggest an important role of the siderophore production system in iron uptake by

Rôle des coopératives dans le fonctionnement du bassin de collecte laitier du Tadla, Maroc

International audienceLe bassin de collecte laitier situé sur le périmètre du Tadla se structure autour d'une usine de transformation industrielle approvisionnée par une myriade de petits éleveurs. Cette atomisation de l'offre a rendu nécessaire la mise en place de coopératives de collecte chargées d'agréger l'offre et d'assurer la chaîne du froid au plus près des producteurs. De fait, ces coopératives jouent un rôle central d'intermédiaire dans la chaîne d'approvisionnement allant de l'eau d'irrigation à la fourniture de lait à l'usine. Cet article, tiré d'une enquête approfondie conduite sur 12 cas, présente dans une première partie les différentes fonctions assurées par les coopératives. Différentes stratégies émergent, fonction de la place tenue par l'équilibre entre volume et qualité du lait produits et la place des activités de diversification dans les performances et les revenus des cas étudiés. Leurs pratiques gestionnaires sont ensuite analysées, concernant leur gestion financière, le paiement des adhérents et leur système d'information. Une relative complexité des circuits de gestion de l'information, couplée à une multiplicité des données et supports à gérer favorisent une certaine opacité des résultats technico-économiques, dommageable à la durabilité de ces organisations. Différentes propositions de recherche et d'intervention tirées de cette analyse sont présentées en conclusion

Utiliser la modélisation pour évaluer l'impact du fonctionnement d'élevages laitiers sur l'économie et la valorisation de l'eau d'irrigation. Cas du Tadla (Maroc)

L'économie et la valorisation de l'eau d'irrigation dépendent des décisions prises par les agriculteurs en matière de choix d'assolement, de modes de conduite des systèmes de production et de stratégies de commercialisation. Si les gestionnaires de périmètre comme les opérateurs aval des filières influencent ces décisions, ils sont souvent démunis face à la diversité des contextes d'action des agriculteurs et à la complexité des réflexions prospectives à mener. Cet article présente une démarche conçue et expérimentée sur le bassin de collecte laitier du périmètre du Tadla au Maroc. Elle combine l'utilisation d'une typologie en 4 types basés sur les stratégies et les pratiques des éleveurs, et d'un outil de simulation confrontant offre et demande alimentaire sur chacun des types. L'utilisation de l'outil est illustrée sur l'exemple des petites exploitations laitières intensives. Différents systèmes fourragers sont comparés et leurs impacts sur la production laitière, la consommation et la valorisation de l'eau d'irrigation sont évalués. Il est ainsi montré que les systèmes combinant maïs ensilage et luzerne sont plus intéressants que les systèmes à base de luzerne sur tous ces plans. Les limites de la démarche touchent à la base de données nécessaire pour valider la typologie sur l'ensemble de la population des éleveurs et pour paramétrer le modèle, aux simplifications apportées à la représentation des processus de gestion et à l'ergonomie de l'application

Type Ia Supernovae Rates and Galaxy Clustering from the CFHT Supernova Legacy Survey

The Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS) has created a large homogeneous database of intermediate redshift (0.2 < z < 1.0) type Ia supernovae (SNe Ia). The SNLS team has shown that correlations exist between SN Ia rates, properties, and host galaxy star formation rates. The SNLS SN Ia database has now been combined with a photometric redshift galaxy catalog and an optical galaxy cluster catalog to investigate the possible influence of galaxy clustering on the SN Ia rate, over and above the expected effect due to the dependence of SFR on clustering through the morphology-density relation. We identify three cluster SNe Ia, plus three additional possible cluster SNe Ia, and find the SN Ia rate per unit mass in clusters at intermediate redshifts is consistent with the rate per unit mass in field early-type galaxies and the SN Ia cluster rate from low redshift cluster targeted surveys. We also find the number of SNe Ia in cluster environments to be within a factor of two of expectations from the two component SNIa rate model.Comment: 21 pages, 2 figures, 6 tables, accepted for publication in A

Hubble Space Telescope studies of low-redshift Type Ia supernovae: Evolution with redshift and ultraviolet spectral trends

We present an analysis of the maximum light, near ultraviolet (NUV; 2900-5500 A) spectra of 32 low redshift (0.001<z<0.08) Type Ia supernovae (SNe Ia), obtained with the Hubble Space Telescope (HST). We combine this spectroscopic sample with high-quality gri light curves obtained with robotic telescopes to measure photometric parameters, such as stretch, optical colour, and brightness. By comparing our data to a comparable sample of SNe Ia at intermediate-z (0.4<z<0.9), we detect modest spectral evolution (3-sigma), in the sense that our mean low-z NUV spectrum has a depressed flux compared to its intermediate-z counterpart. We also see a strongly increased dispersion about the mean with decreasing wavelength, confirming the results of earlier surveys. These trends are consistent with changes in metallicity as predicted by contemporary SN Ia spectral models. We also examine the properties of various NUV spectral diagnostics in the individual spectra. We find a general correlation between stretch and the velocity (or position) of many NUV spectral features. In particular, we observe that higher stretch SNe have larger Ca II H&K velocities, that also correlate with host galaxy stellar mass. This latter trend is probably driven by the well-established correlation between stretch and stellar mass. We find no trends between UV spectral features and optical colour. Mean spectra constructed according to whether the SN has a positive or negative Hubble residual show very little difference at NUV wavelengths, indicating that the NUV evolution and variation we identify do not directly correlate with Hubble residuals. Our work confirms and strengthens earlier conclusions regarding the complex behaviour of SNe Ia in the NUV spectral region, but suggests the correlations we find are more useful in constraining progenitor models than improving the use of SNe Ia as cosmological probes.Comment: 22 pages, 14 figures, accepted in MNRAS with minor changes - Spectra are available on WISeREP, http://www.weizmann.ac.il/astrophysics/wiserep

Association between canine leishmaniosis and Ehrlichia canis co-infection: a prospective case-control study

Abstract Background In the Mediterranean basin, Leishmania infantum is a major cause of disease in dogs, which are frequently co-infected with other vector-borne pathogens (VBP). However, the associations between dogs with clinical leishmaniosis (ClinL) and VBP co-infections have not been studied. We assessed the risk of VBP infections in dogs with ClinL and healthy controls. Methods We conducted a prospective case-control study of dogs with ClinL (positive qPCR and ELISA antibody for L. infantum on peripheral blood) and clinically healthy, ideally breed-, sex- and age-matched, control dogs (negative qPCR and ELISA antibody for L. infantum on peripheral blood) from Paphos, Cyprus. We obtained demographic data and all dogs underwent PCR on EDTA-blood extracted DNA for haemoplasma species, Ehrlichia/Anaplasma spp., Babesia spp., and Hepatozoon spp., with DNA sequencing to identify infecting species. We used logistic regression analysis and structural equation modelling (SEM) to evaluate the risk of VBP infections between ClinL cases and controls. Results From the 50 enrolled dogs with ClinL, DNA was detected in 24 (48%) for Hepatozoon spp., 14 (28%) for Mycoplasma haemocanis, 6 (12%) for Ehrlichia canis and 2 (4%) for Anaplasma platys. In the 92 enrolled control dogs, DNA was detected in 41 (45%) for Hepatozoon spp., 18 (20%) for M. haemocanis, 1 (1%) for E. canis and 3 (3%) for A. platys. No Babesia spp. or “Candidatus Mycoplasma haematoparvum” DNA was detected in any dog. No statistical differences were found between the ClinL and controls regarding age, sex, breed, lifestyle and use of ectoparasitic prevention. A significant association between ClinL and E. canis infection (OR = 12.4, 95% CI: 1.5–106.0, P = 0.022) was found compared to controls by multivariate logistic regression. This association was confirmed using SEM, which further identified that younger dogs were more likely to be infected with each of Hepatozoon spp. and M. haemocanis, and dogs with Hepatozoon spp. were more likely to be co-infected with M. haemocanis. Conclusions Dogs with ClinL are at a higher risk of co-infection with E. canis than clinically healthy dogs. We recommend that dogs diagnosed with ClinL should be tested for E. canis co-infection using PCR

Geochemical Study of Natural CO2 Emissions in the French Massif Central: How to Predict Origin, Processes and Evolution of CO2 Leakage

International audienceThis study presents an overview of some results obtained within the French ANR (National Agency of Research) supported Géocarbone-Monitoring research program. The measurements were performed in Sainte-Marguerite, located in the French Massif Central. This site represents a natural laboratory for CO2/fluid/rock interactions studies, as well as CO2 migration mechanisms towards the surface. The CO2 leaking character of the studied area also allows to test and validate measurements methods and verifications for the future CO2 geological storage sites. During these surveys, we analyzed soil CO2 fluxes and concentrations. We sampled and analyzed soil gases, and gas from carbo-gaseous bubbling springs. A one-month continuous monitoring was also tested, to record the concentration of CO2 both in atmosphere and in the soil at a single point. We also developed a new methodology to collect soil gas samples for noble gas abundances and isotopic analyses, as well as carbon isotopic ratios. Our geochemical results, combined with structural geology, show that the leaking CO2 has a very deep origin, partially mantle derived. The gas rises rapidly along normal and strike-slip active faults. CO2 soil concentrations (also showing a mantle derived component) and CO2 fluxes are spatially variable, and reach high values. The recorded atmospheric CO2 is not very high, despite the important CO2 degassing throughout the whole area

VIMOS Ultra-Deep Survey (VUDS): Witnessing the Assembly of a Massive Cluster at \u3cem\u3ez\u3c/em\u3e ~ 3.3

Using new spectroscopic observations obtained as part of the VIMOS Ultra-Deep Survey (VUDS), we performed a systematic search for overdense environments in the early universe (z\u3e 2) and report here on the discovery of Cl J0227-0421, a massive protocluster at z = 3.29. This protocluster is characterized by both the large overdensity of spectroscopically confirmed members, δgal = 10.5 ± 2.8, and a significant overdensity in photometric redshift members. The halo mass of this protocluster is estimated by a variety of methods to be ~3 × 1014ℳ⊙ at z ~ 3.3, which, evolved to z = 0 results in a halo mass rivaling or exceeding that of the Coma cluster. The properties of 19 spectroscopically confirmed member galaxies are compared with a large sample of VUDS/VVDS galaxies in lower density field environments at similar redshifts. We find tentative evidence for an excess of redder, brighter, and more massive galaxies within the confines of the protocluster relative to the field population, which suggests that we may be observing the beginning ofenvironmentally induced quenching. The properties of these galaxies are investigated, including a discussion of the brightest protocluster galaxy, which appears to be undergoing vigorous coeval nuclear and starburst activity. The remaining member galaxies appear to have characteristics that are largely similar to the field population. Though we find weaker evidence of the suppression of the median star formation rates among and differences in the stacked spectra of member galaxies with respect to the field, we defer any conclusions about these trends to future work with the ensemble of protostructures that are found in the full VUDS sample