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BACKGROUND: The effectiveness of the analysis of cell wall-bound hydroxycinnamic acids and the composition of lignin to evaluate the in vivo digestibility of a silage collection with unknown botanical composition was evaluated., RESULTS: Syringyl units content and total etherified phenols showed the highest correlation coefficients with in vivo dry matter digestibility (IVDMD) (r = − 0.792 and r = − 0.703, respectively), while guaiacyl units and total phenols showed the highest correlation coefficients with in vivo organic matter digestibility (IVOMD) (r = − 0.871 and r = − 0.817, respectively). Using the above-mentioned chemical parameters, 10 equations were also developed to predict in vivo digestibility. The prediction of IVDMD produced a high adjusted R2 value (0.710) using syringyl, total lignin, etherified total phenols, esterified ferulic acid and total phenol content as predictors. The prediction of IVOMD produced a higher adjusted R2 value (0.821) using guaiacyl, total phenols, total ferulic acid and etherified p-coumaric acid content as predictors., CONCLUSION: Cell wall digestibility depends on a multiplicity of factors and it is not possible to attribute a causal effect on in vivo digestibility to any single factor. However, syringyl and guaiacyl content and etherified phenols emerge as good predictors of digestibility., Xunta de Galicia (PGIDIT04RAG503018PR); INIA–European Social Fund

International audience

Colloque avec actes et comité de lecture. Internationale.; International audience; Nous présentons une étude paramétrique de la résistance au cisaillement d'un milieu granulaire cohésif simulé par la méthode de dynamique des contacts. Cette étude est basée sur un modèle de cohésion qui tient compte de la résistance à la traction, au glissement, et au roulement dans les contacts entre les particules. La résistance macroscopique est évaluée par la compression biaxiale des échantillons numériques comportant plusieurs milliers de particules en deux dimensions. Nos résultats suggèrent que : 1) l'angle de frottement interne peut être vu comme la somme de trois contributions : une géométrique, une frictionnelle, et une associée à la dilatance ; 2) les coefficients de frottement sont les seuls paramètres de résistance microscopiques à l'origine de l'angle de frottement interne et de l'angle de dilatance ; et 3) l'adhésion entre particules est le seul paramètre de résistance microscopique à l'origine de la résistance à la traction.

International audience; By means of the contact dynamics discrete element method, we investigate the quasi-static behavior of granular media composed of rigid frictional particles. Eluding specific modeling of the contact rheology, this method is suitable for numerical simulation of the plastic deformations of granular materials. We studied the macroscopic stress-strain and volume-change behavior, as well as force transmission and shear instabilities, in a two-dimensional biaxial geometry for dense samples composed of 5000 rigid disks. The peak and residual strengths and shear bands were analyzed by varying the confining pressure and the coefficient of friction between particles. The results are consistent with well-known features of the plasticity of noncohesive granular media. The mechanical behavior is rigid-plastic governed by a Mohr-Coulomb yield criterion and showing strain hardening and softening. Conjugated shear bands characterize plastic failure. The volumetric strain is globally dilatant with considerable expansion observed along shear bands. The macroscopic coefficient of friction, determined from peak and residual strengths, increases nonlinearly and saturates to a constant value as a function of contact friction. The strong force chains are mostly parallel to the major principal stress axis, yet deviations are observed near the shear bands. These chains are often composed of particles that are larger than the average. The deviatoric stress shows small fluctuations often in the form of rapid falls that are correlated with tiny contractional events. This behavior is interpreted in terms of the propagation of dynamic shear instabilities along the shear bands, in close analogy with stick-slip behavior.

Del latín filiu - filii que quiere decir hijo, se ha entendido como el vínculo de parentesco de consanguinidad entre dos personas, en donde una es padre o madre de la otra. Si se establece solamente frente al primero se le llama paternidad y ante la segundo, maternidad. A través de este ensayo, quiero expresar mi opinión sobre el tema de la filiación, introduciendo el nuevo factor que es el de la inseminación artificial y hasta lo famosa clonación que tanto se discute en lo actualidad. Debemos entender que los hijos deben tener unos podres que lo orienten y eduquen v con la irresponsabilidad de muchos podres son las instancias judiciales. las que deben intermediar poro determinar responsabilidades. Hago una presentación de cuales pueden ser las alternativos que se presentan paro fijar a quien pertenecen los hijos legalmente.