Effect of pH and level of concentrate in the diet on the production of biohydrogenation intermediates in a dual-flow continuous culture

Milk fat depression in cows fed high-grain diets has been related to an increase in the concentration of trans-10 C-18:1 and trans-10, cis-12 conjugated linoleic acid (CLA) in milk. These fatty acids (FA) are produced as a result of the alteration in rumen biohydrogenation of dietary unsaturated FA. Because a reduction in ruminal pH is usually observed when high-concentrate diets are fed, the main cause that determines the alteration in the biohydrogenation pathways is not clear. The effect of pH (6.4 vs. 5.6) and dietary forage to concentrate ratios (F:C; 70:30 F:C vs. 30:70 F:C) on rumen microbial fermentation, effluent FA profile, and DNA concentration of bacteria involved in lipolysis and biohydrogenation processes were investigated in a continuous culture trial. The dual-flow continuous culture consisted of 2 periods of 8 d (5 d for adaptation and 3 d for sampling), with a 2 x 2 factorial arrangement of treatments. Samples from solid and liquid mixed effluents were taken for determination of total N, ammonia-N, and volatile fatty acid concentrations, and the remainder of the sample was lyophilized. Dry samples were analyzed for dry matter, ash, neutral and acid detergent fiber, FA, and purine contents. The pH 5.6 reduced organic matter and fiber digestibility, ammonia-N concentration and flow, and crude protein degradation, and increased nonammonia and dietary N flows. The pH 5.6 decreased the flow of C-18:0, trans-11 C-18:1 and cis-9, trans-11 CLA, and increased the flow of trans-10 C-18:1, C18:2n-6, C18:3n-3, trans-11, cis-15 C-18:2 and trans-10, cis-12 CLA in the 1 h after feeding effluent. The pH 5.6 reduced Anaerovibrio lipolytica (32.7 vs. 72.1 pg/10 ng of total DNA) and Butyrivibrio fibrisolvens vaccenic acid subgroup (588 vs. 1,394 pg/10 ng of total DNA) DNA concentrations. The high-concentrate diet increased organic matter and fiber digestibility, nonammonia and bacterial N flows, and reduced ammonia-N concentration and flow. The high-concentrate diet reduced trans-11 C-18:1 and trans-10 C-18:1, and increased C18:2n-6, C18:3n-3 and trans-10, cis-12 CLA proportions in the 1 h after feeding effluent. The increase observed in trans-10, cis-12 CLA proportion in the 1 h after feeding effluent due to the high-concentrate diet was smaller that that observed at pH 5.6. Results indicate that the pH is the main cause of the accumulation of trans-10 C-18:1 and trans-10, cis-12 CLA in the effluent, but the trans-10, cis-12 CLA proportion can be also affected by high levels of concentrate in the diet

Microbial individuality: how single-cell heterogeneity enables population level strategies.

Much of our knowledge of microbial life is only a description of average population behaviours, but modern technologies provide a more inclusive view and reveal that microbes also have individuality. It is now acknowledged that isogenic cell-to-cell heterogeneity is common across organisms and across different biological processes. This heterogeneity can be regulated and functional, rather than just reflecting tolerance to noisy biochemistry. Here, we review recent advances in our understanding of microbial heterogeneity, with an emphasis on the pervasiveness of heterogeneity, the mechanisms that sustain it, and how heterogeneity enables collective function.The research has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 338060. The work in the Locke laboratory is also supported by a fellowship from the Gatsby Foundation (GAT3273/GLC).This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.mib.2015.01.00

Obituary of Dr. Angelo Di George

[No abstract available

The effect of the G-Layer on the viscoelastic properties of tropical hardwoods

International audienceContext and aim : This study aimed to examine the effect of the tension wood G‐layer on the viscoelastic properties of wood. Methods : Tension wood and opposite wood samples were obtained from six French Guianese tropical rainforest species (Sextonia rubra, Ocotea guyanensis, Inga alba, Tachigali melinoni, Iyranthera sagotiana and Virola michelii); the tension wood of the former three of these species had a Glayer, whilst the tension wood from the latter three had no Glayer. Tensile dynamic mechanical analysis (DMA) was performed on green never dried wood samples in the longitudinal direction with samples submerged in a water bath at a temperature (30°C) and frequency (1 Hz) representative of the conditions experienced by wood within a living tree. Then, DMA was repeated with samples conditioned to an air-dried state. Finally, samples were oven-dried to measure longitudinal shrinkage. Results : Tension wood did not always have a higher longitudinal storage (elastic) modulus than opposite wood from the same tree regardless of the presence or absence of a G‐layer. For the species containing a G‐layer, tension wood had a higher damping coefficient and experienced a greater longitudinal shrinkage upon drying than opposite wood from the same species. No difference was found in damping coefficients between tension wood and opposite wood for the species that had no G‐layer. Conclusion : It is proposed that the different molecular composition of the G-layer matrix has an influence on the viscoelasticity of wood, even if a biomechanical gain is not yet clear. This study shows that rheological properties and longitudinal shrinkage can be used to detect the presence of a G‐layer in tension wood

Rock glaciers and paraglacial features influence stream invertebrates in a deglaciating Alpine area

This is the pre-peer reviewed version of the following article: Brighenti, S, Tolotti, M, Bertoldi, W, Wharton, G, Bruno, MC. Rock glaciers and paraglacial features influence stream invertebrates in a deglaciating Alpine area. Freshwater Biology. 2020; 00: 1– 14. https://doi.org/10.1111/fwb.13658, which has been published in final form at https://doi.org/10.1111/fwb.13658. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions

Continuum de prévention des blessures sportives chez les jeunes athlètes, en collaboration avec les Jeux du Québec 2014

Travail d'intégration présenté à la Faculté de médecine en vue de l’obtention du grade de maîtrise en physiothérapieIntroduction/problématique : La participation des jeunes aux sports est en ascension constante depuis plusieurs années. C’est pourquoi l’équipe médicale des Jeux du Québec de Longueuil 2014 nous a consultés pour approfondir le système de surveillance actuel et les moyens pour prévenir les blessures. Objectifs : Définir les blessures les plus fréquentes dans les différentes disciplines des Jeux. Établir les composantes d’un système de surveillance adapté aux événements sportifs. Informer les athlètes, entraîneurs et parents sur la prévention des blessures. Stratégie méthodologique : Recension de la littérature dans les bases de données PubMed, Medline, Cinhal, Psychinfo. Résultats : Nous avons élaboré des fiches sur les blessures les plus fréquentes dans les sports chez les jeunes. Également, une définition du mot blessure a été conçue et a permis la création d’une grille d’intervention sur le terrain. Nous avons établi des lignes directrices sur les différentes modalités de prévention en physiothérapie pour la tendinopathie à l’épaule et l’entorse à la cheville chez les jeunes. Aussi, des recommandations sur les comportements à adopter chez les parents afin de diminuer le risque de blessures ont été proposées. Conclusion : Il est nécessaire que chaque personne impliquée auprès des athlètes agisse vers un même but : la prévention. Donc, nous recommandons aux Jeux du Québec d’effectuer une collecte de données à partir de la grille basée sur l’épidémiologie pour assurer un meilleur suivi des blessures. De plus, des recommandations sur la prévention seront mises sur le site Internet des Jeux

Computation of Market Equilibria via the Excess Demand Function

We consider the computation of equilibria for exchange economies. The general problem is unlikely to admit efficient algorithms. We develop and adapt a number of tools which allow us to take advantage of the structure of equilibria, when the market satisfies a property, called weak gross substitutability, which guarantees that the equilibria form a convex set. Using these tools we derive two polynomial time algorithms: the first one is a simple and efficient discrete version of the t?atonnement process, while the second one is based on the Ellipsoid method, and achieves a better dependence on the approximation parameter. Our approach does not make use of the specific form of the utility functions of the individual traders, and it is thus more general than previous work