CONVERSION OF A LAMB PRODUCTION SYSTEM TO ORGANIC FARMING: HOW TO MANAGE, FOR WHICH RESULTS?

Two sheep flocks were managed organically (for two years from conversion onwards) under different lambing strategies (1 lambing/year vs. 3 lambings every two years). The second system was tested as there was a producer’s interest in high productivity that is a guarantee of good economic results in conventional. Reproduction, feeding, lamb production, carcass quality, health (particularly internal parasitism), economic return of the flock, grass production, and pasture biodiversity were evaluated. The lambs were bred under low therapeutic input. The economical advantage of increasing lambing frequency was not demonstrated, whereas this strategy complexified management and resulted in higher internal parasitic infection of the lambs, and finally showed a lower stability. There were difficulties in establishing a very high feed self-sufficiency in both systems, especially the more intensive system (4 points lower), due to harsh climatic conditions; following this five-year experiment, we are changing our strategy to provide nitrogen in the systems

CONVERSION OF A LAMB PRODUCTION SYSTEM TO ORGANIC FARMING: HOW TO MANAGE, FOR WHAT RESULTS?

Two sheep flocks were managed organically for two years from conversion under different lambing strategies (1 lambing/year vs. 3 lambings every two years). The second system was tested because pf a producer’s interest in high productivity, which is a guarantee of good economic results in conventional production.. Reproduction, feeding, lamb production, carcass quality, health (particularly internal parasitism), economic return of the flock, grass production, and pasture biodiversity were evaluated. The lambs were bred with low therapeutic inputs. No economic advantage of increasing lambing frequency was demonstrated, whereas this strategy complicated management and resulted in higher internal parasitic infection of the lambs, and finally showed lower stability. There were difficulties in establishing a very high feed self-sufficiency in both systems, especially the more intensive system (4 points lower), due to harsh climatic conditions. Following this five-year experiment, we are changing our strategy to provide nitrogen in the systems

Helminth associations in white-toothed shrews crocidura russula (insectivora: soricidae) from the albufera natural park, Spain

The helminths of 218 white-toothed shrews from 29 sites in 2 biotopes in the Albufera Natural Park (Valencia, Spain) were examined from July 1990 to August 1991. An association analysis of helminths occurring at a prevalence of more than 4% was carried out for 4 species of cestodes located in the intestine (Hymenolepis pistillum, H. scalaris, H. tiara, and Pseudhymenolepis redonica) and 3 species of nematodes (Pseudophysaloptera sp. located in the stomach, Stammerinema rhopocephala larvae in the intestine and abdominal cavity, and Porrocaecum sp. in the thoracic and abdominal cavities). Bivariate (species pairs) versus multivariate analyses (associations within the entire set of species) were performed of presence–absence and of quantitative records (influence of intensity on associations). The associations were evaluated with respect to the sex and age of the host and to the sampling date and sites. The host and environment played a limited role, and the major determinant of species assemblage was phylogenetic. Positive associations were found among both the cestodes and the nematodes, whereas negative associations were found between cestodes and nematodes. The type of life cycle was probably the second greatest determinant of species associations. Nematodes using shrews as a paratenic host or as their definitive host were both positively associated.Esteban Sanchis, Jose Guillermo, [email protected]

Sheep enteric cestodes and their influence on clinical indicators used in targeted selective treatments against gastrointestinal nematodes

Clinical indicators such as diarrhoea (DISCO) or anaemia (FAMACHA©) are used as a measure for targeted selective treatments against gastrointestinal nematodes (GIN). Enteric cestodes such as Moniezia may interfere directly with DISCO or indirectly with the FAMACHA© score. We investigated 821 Ouled Djellal rams naturally infected in a steppe environment (GIN alone, cestodes alone, GIN and cestodes) or not. The rams were treated with ivermectin 2 months before being slaughtered to reduce the impact of nematodes on the clinical scores; however, persistent or newly acquired GINs were not related to both scores. Of the non-infected rams (n = 296), 26% identified as needing treatment against GIN using the FAMACHA score, and 34.5% using DISCO would have been thus selected. This implies that the clinical indicators used for the targeted selective treatment of gastrointestinal nematodes are not fully reliable when a low infection is recorded and may well be influenced by confounding factors. As expected, only DISCO was affected by cestode infection, and we suggest that the presence of Moniezia should also be taken into consideration

Gastrointestinal strongyles of ruminants : mechanisms of anthelmintic resistance and consequences on their management

The management of gastrointestinal strongyle infestations in ruminants relies mostly on anthelmintics. Only three chemical families are available, and gastrointestinal strongyles resistance is increasing. The resistance mechanisms are relatively well known for benzimidazoles (involving one gene with two alleles), whereas the genetic determinism of the resistance to macrocyclic lactones or imidazothiazoles (levamisole) is still poorly understood, but probably involves multigenic regulation. A double approach (candidate genes and transcriptomic) is proposed for levamisole resistance and the first results are presented. It is very important to understand resistance mechanisms to reduce their occurrences. Examples with benzimidazoles are presented to describe interactions between the type of genetic mechanism and the speed with which resistance appears and expands, the efficacy of selective pressure by treatments, and the role of refugia.La gestion des infestations du tube digestif par les strongles chez les ruminants est essentiellement assurée par les traitements anthelminthiques. Seules trois familles chimiques sont disponibles et des phénomènes de résistance à ces produits sont apparus chez les strongles gastro-intestinaux. Les mécanismes de résistance concernant la famille des benzimidazoles sont relativement bien établis (un gène avec deux allèles est impliqué), alors que pour la famille des lactones macrocycliques ou celle des imidazothiazoles (lévamisole), les déterminismes génétiques, encore peu connus, sont sans doute multigéniques. Une double approche (« gènes candidats » et transcriptomique) est proposée pour le lévamisole et les premiers résultats sont présentés. La compréhension des mécanismes d'action est très importante pour tenter de réduire l'apparition de résistance. Des exemples concernant les benzimidazoles sont utilisés pour décrire l'interaction entre le type de mécanisme de résistance et la vitesse d'apparition et de diffusion de la résistance, l'efficacité des pressions sélectives par les traitements et le rôle des refuges

Physical Realization of a Supervised Learning System Built with Organic Memristive Synapses

International audienceMultiple modern applications of electronics call for inexpensive chips that can perform complex operations on natural data with limited energy. A vision for accomplishing this is implementing hardware neural networks, which fuse computation and memory, with low cost organic electronics. A challenge, however, is the implementation of synapses (analog memories) composed of such materials. In this work, we introduce robust, fastly programmable, nonvolatile organic memristive nanodevices based on electrografted redox complexes that implement synapses thanks to a wide range of accessible intermediate conductivity states. We demonstrate experimentally an elementary neural network, capable of learning functions, which combines four pairs of organic memristors as synapses and conventional electronics as neurons. Our architecture is highly resilient to issues caused by imperfect devices. It tolerates inter-device variability and an adaptable learning rule offers immunity against asymmetries in device switching. Highly compliant with conventional fabrication processes, the system can be extended to larger computing systems capable of complex cognitive tasks, as demonstrated in complementary simulations

Projet NoBaby : Apprentissage de la conception/réalisation de produits en mode projet

L'Institut Supérieur d'ingénieur de Franche-Comté est une jeune école d'ingénieurs spécialisée dans le génie biomédical. Les étudiants recrutés viennent d'horizons et de cultures scientifique et technique très différents. Dans le cadre des enseignements de construction mécanique, on propose de concevoir et réaliser un système mécanique. Les étudiants doivent concevoir un prototype fonctionnel du produit. Il est ensuite réalisé par prototypage rapide. On propose ici de donner la structuration pédagogique de ce type de projet et des démarches à suivre

Charge-radius change and nuclear moments in the heavy tin isotopes from laser spectroscopy: Charge radius of 132^{132}Sn

NESTER ACCLaser spectroscopy measurements have been carried out on the neutron-rich tin isotopes with the COMPLIS experimental setup. Using the $5s^25p^2$ $^3P_0 \rightarrow 5s^25_p6s$ $^3P_1$ optical transition, hyperfine spectra of $^{126-132}$Sn and $^{125,127,129-131}Sn^m$ were recorded for the first time. The nuclear moments and the mean square charge radius variation ($\delta) were extracted. From the quadrupole moment values, these nuclei appear to be spherical. The magnetic moments measured are thus compared with those predicted by spherical basis approaches. From the measured$\delta, the absolute charge radii of these isotopes were deduced in particular that of the doubly magic $^{132}$Sn nucleus. The comparison of the results with several mean-field-type calculations have shown that dynamical effects play an important role in the tin isotopes

Recent results on neutron rich tin isotopes by laser spectroscopy

Laser spectroscopy measurements have been performed on neutron rich tin isotopes using the COMPLIS experimental setup. The nuclear charge radii of the even-even isotopes from A=108 to 132 are compared to the results of macroscopic and microscopic calculations. The improvements and optimizations needed to perform the isotope shift measurement on $^{134}$Sn are presented