Diagnostic et perspectives de développement de la filière viande bovine biologique des Pays de la Loire

La filière viande bovine biologique des Pays de la Loire présente les particularités suivantes : - de nombreux acteurs n’interviennent qu’en prestation de service . C’est le cas des organisations de producteurs pour la collecte, l’estimation, le transport et la facturation des animaux, c’est le cas aussi de certains abattoirs et ateliers de découpe agréés sollicités pour l’approvisionnement des bouchers, des magasins spécialisés ou des producteurs – vendeurs. Dans l’état actuel de l’organisation de la filière et quelles que soient les compétences de ces intervenants, ils n’ont pas le pouvoir d’intervenir dans la dynamique de filière. - Pour chaque maillon de la filière (production, collecte, transformation, distribution) nous observons une réelle hétérogénéité des acteurs. Des relations privilégiées se sont nouées entre certains transformateurs et certains distributeurs, dessinant ainsi deux voies de transformation-distribution : la voie « industrielle » et la voie « spécialisée ». Cependant nous ne pouvons pas parler de segmentation en sous-filières dans la mesure où le maillon production n’est pas segmenté. Ainsi, malgré la diversité des sensibilités des producteurs, ils ne sont pas impliqués dans le choix des débouchés de leurs animaux. Ainsi il n’existe pas de segmentation de la production en fonction de sous-filières différenciées. - E-Bio constitue un acteur spécifique dans la mesure où les animaux ne transitent pas physiquement par cette structure mais il assure la centralisation de l’offre. Le rôle d’E-Bio est organisationnel. E-Bio sous-traite les fonctions techniques associées classiquement au regroupement de l’offre (estimation, collecte, transport) à des organisations de producteurs Cela permet de constater que les opérateurs vraiment actifs se situent - dans la filière artisanale par la dynamique des artisans bouchers, - dans la filière d’accès aux magasins spécialisés par la dynamique des producteurs surtout sous la coordination d’E-Bio, - dans la filière d’accès aux GMS par la dynamique des distributeurs et des industriels, avec l’appui d’E-Bio, - dans la filière vente directe par la dynamique des producteurs. L’organisation de la filière ainsi caractérisée, il s’agit maintenant de synthétiser le contexte d’expression des dynamiques des acteurs. La viande bovine bio est un des segments particuliers du marché de la viande bovine. Les producteurs biologiques et leurs organisations travaillent avec des acteurs majeurs de la filière viande bovine. Ainsi, les perspectives d’évolution du contexte et les stratégies de certains acteurs de la filière biologique ne peuvent s’appréhender indépendamment du contexte plus général de la filière viande bovine

Nitrous oxide does not produce a clinically important sparing effect during closed-loop delivered propofol-remifentanil anaesthesia guided by the bispectral index: a randomized multicentre study†‡

Background Nitrous oxide (N2O) offers both hypnotic and analgesic characteristics. We therefore tested the hypothesis that N2O administration decreases the amount of propofol and remifentanil given by a closed-loop automated controller to maintain a similar bispectral index (BIS). Methods In a randomized multicentre double-blind study, patients undergoing elective surgery were randomly assigned to breathe 60% inspired N2O (N2O group) or 40% oxygen (AIR group). Anaesthesia depth was evaluated by the proportion of time where BIS was within the range of 40-60 (BIS40-60). The primary outcomes were propofol and remifentanil consumption, with reductions of 20% in either being considered clinically important. Results A total of 302 patients were randomized to the N2O group and 299 to the AIR group. At similar BIS40-60 [79 (67-86)% vs 76 (65-85)%], N2O slightly decreased propofol consumption [4.5 (3.7-5.5) vs 4.8 (4.0-5.9) mg kg−1 h−1, P=0.032], but not remifentanil consumption [0.17 (0.12-0.23) vs 0.18 (0.14-0.24) µg kg−1 min−1]. For the subgroups of men, at similar BIS40-60 [80 (72-88)% vs 80 (70-87)%], propofol [4.2 (3.4-5.3) vs 4.4 (3.6-5.4) mg kg−1 h−1] and remifentanil [0.19 (0.13-0.25) vs 0.18 (0.15-0.23) µg kg−1 min−1] consumptions were similar in the N2O vs AIR group, respectively. For the subgroups of women, at similar BIS40-60 [76 (64-84)% vs 72 (62-82)%], propofol [4.7 (4.0-5.8) vs 5.3 (4.5-6.6) mg kg−1 h−1, P=0.004] and remifentanil [0.18 (0.13-0.25) vs 0.20 (0.15-0.27) µg kg−1 min−1, P=0.029] consumptions decreased with the co-administration of N2O. Conclusions With automated drug administration titrated to comparable BIS, N2O only slightly reduced propofol consumption and did not reduce remifentanil consumption. There was a minor gender dependence, but not by a clinically important amount. Clinical trial registration This study was registered at ClinicalTrials.gov, number NCT0054720

High-resolution genetic map and QTL analysis of growth-related traits of Hevea brasiliensis cultivated under suboptimal temperature and humidity conditions

Rubber tree (Hevea brasiliensis) cultivation is the main source of natural rubber worldwide and has been extended to areas with suboptimal climates and lengthy drought periods; this transition affects growth and latex production. High-density genetic maps with reliable markers support precise mapping of quantitative trait loci (QTL), which can help reveal the complex genome of the species, provide tools to enhance molecular breeding, and shorten the breeding cycle. In this study, QTL mapping of the stem diameter, tree height, and number of whorls was performed for a full-sibling population derived from a GT1 and RRIM701 cross. A total of 225 simple sequence repeats (SSRs) and 186 single-nucleotide polymorphism (SNP) markers were used to construct a base map with 18 linkage groups and to anchor 671 SNPs from genotyping by sequencing (GBS) to produce a very dense linkage map with small intervals between loci. The final map was composed of 1,079 markers, spanned 3,779.7 cM with an average marker density of 3.5 cM, and showed collinearity between markers from previous studies. Significant variation in phenotypic characteristics was found over a 59-month evaluation period with a total of 38 QTLs being identified through a composite interval mapping method. Linkage group 4 showed the greatest number of QTLs (7), with phenotypic explained values varying from 7.67 to 14.07%. Additionally, we estimated segregation patterns, dominance, and additive effects for each QTL. A total of 53 significant effects for stem diameter were observed, and these effects were mostly related to additivity in the GT1 clone. Associating accurate genome assemblies and genetic maps represents a promising strategy for identifying the genetic basis of phenotypic traits in rubber trees. Then, further research can benefit from the QTLs identified herein, providing a better understanding of the key determinant genes associated with growth of Hevea brasiliensis under limiting water conditions

Linkage disequilibrium and population structure in wild and cultivated populations of rubber tree (Hevea brasiliensis).

Abstract: Among rubber tree species, which belong to the Hevea genus of the Euphorbiaceae family, Hevea brasiliensis (Willd. ex Adr.de Juss.) Muell. Arg. is the main commercial source of natural rubber production worldwide. Knowledge of the population structure and linkage disequilibrium (LD) of this species is essential for the efficient organization and exploitation of genetic resources. Here, we obtained single-nucleotide polymorphisms (SNPs) using a genotyping-by-sequencing (GBS) approach and then employed the SNPs for the following objectives: (i) to identify the positions of SNPs on a genetic map of a segregating mapping population, (ii) to evaluate the population structure of a germplasm collection, and (iii) to detect patterns of LD decay among chromosomes for future genetic association studies in rubber tree. A total of 626 genotypes, including both germplasm accessions (368) and individuals from a genetic mapping population (254), were genotyped. A total of 77,660 and 21,283 SNPs were detected by GBS in the germplasm and mapping populations, respectively. The mapping population, which was previously mapped, was constructed with 1,062 markers, among which only 576 SNPs came from GBS, reducing the average interval between two adjacent markers to 4.4 cM. SNPs from GBS genotyping were used for the analysis of genetic structure and LD estimation in the germplasm accessions. Two groups, which largely corresponded to the cultivated and wild populations, were detected using STRUCTURE and via principal coordinate analysis. LD analysis, also using the mapped SNPs, revealed that non-random associations varied along chromosomes, with regions of high LD interspersed with regions of low LD. Considering the length of the genetic map (4,693 cM) and the mean LD (0.49 for cultivated and 0.02 for wild populations), a large number of evenly spaced SNPs would be needed to perform genome-wide association studies in rubber tree, and the wilder the genotypes used, the more difficult the mapping saturation

Background Light in Potential Sites for the ANTARES Undersea Neutrino Telescope

The ANTARES collaboration has performed a series of {\em in situ} measurements to study the background light for a planned undersea neutrino telescope. Such background can be caused by $^{40}$K decays or by biological activity. We report on measurements at two sites in the Mediterranean Sea at depths of 2400~m and 2700~m, respectively. Three photomultiplier tubes were used to measure single counting rates and coincidence rates for pairs of tubes at various distances. The background rate is seen to consist of three components: a constant rate due to $^{40}$K decays, a continuum rate that varies on a time scale of several hours simultaneously over distances up to at least 40~m, and random bursts a few seconds long that are only correlated in time over distances of the order of a meter. A trigger requiring coincidences between nearby photomultiplier tubes should reduce the trigger rate for a neutrino telescope to a manageable level with only a small loss in efficiency.Comment: 18 pages, 8 figures, accepted for publication in Astroparticle Physic