Analytical solution of compression, free swelling and electrical loading of saturated charged porous media

Analytical solutions are derived for one-dimensional consolidation, free swelling and electrical loading of a saturated charged porous medium. The governing equations describe infinitesimal deformations of linear elastic isotropic charged porous media saturated with a mono-valent ionic solution. From the governing equations a coupled diffusion equation in state space notation is derived for the electro-chemical potentials, which is decoupled introducing a set of normal parameters, being a linear combination of the eigenvectors of the diffusivity matrix. The magnitude of the eigenvalues of the diffusivity matrix correspond to the time scales for Darcy flow, diffusion of ionic constituents and diffusion of electrical potential

The prevalence of middle ear pathogens in the outer ear canal and the nasopharyngeal cavity of healthy young adults

AbstractCulturing middle ear fluid samples from children with chronic otitis media with effusion (OME) using standard techniques results in the isolation of bacterial species in approximately 30–50% of the cases. Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, the classic middle ear pathogens of acute otitis media, are involved but, recently, several studies suggested Alloiococcus otitidis as an additional pathogen. In the present study, we used species-specific PCRs to establish the prevalence, in both the nasopharyngeal cavity and the outer ear, of H. influenzae, M. catarrhalis, S. pneumoniae and A. otitidis. The study group consisted of 70 healthy volunteers (aged 19–22 years). The results indicate a high prevalence (>80%) of A. otitidis in the outer ear in contrast to its absence in the nasopharynx. H. influenzae was found in both the outer ear and the nasopharynx (6% and 14%, respectively), whereas S. pneumoniae and M. catarrhalis were found only in the nasopharynx (9% and 34%, respectively). A. otitidis, described as a fastidious organism, were able to be cultured using an optimized culture protocol, with prolonged incubation, which allowed the isolation of A. otitidis in five of the nine PCR-positive samples out of the total of ten samples tested. Given the absence of the outer ear inhabitant A. otitidis from the nasopharynx, its role in the aetiology of OME remains ambiguous because middle ear infecting organisms are considered to invade the middle ear from the nasopharynx through the Eustachian tube

Agronomic Value of Mixture of Perennial Rye-Grass Cultivars: Preliminary Results

Mixtures of grass and legume species are commonly used in sown grasslands. Mixtures have been shown to be favourable for stable production over cycles and years due to a succession of species over time (Mosimann & Charles, 1996 ; Nie et al, 2004). However, little is known whether the genetic variation in pure stands has an influence on the agronomic value and its variation over seasons

QTLs for Morphogenetic Traits in Medicago Truncatula

Plant morphogenesis that includes growth, development and flowering date, drives a large number of agronomical important traits in both grain and forage crops. Quantitative trait locus (QTL) mapping is a way to locate zones of the genome that are involved in the variations observed in a segregating population. Co-location of QTLs and candidate genes is an indication of the involvement of the genes in the variation. The objective of this study was to analyse segregation of aerial morphogenetic traits in a mapping population of recombinant inbred lines of the model legume species M. truncatula , to locate QTLs and candidate genes

Evaluation of Sweet Grain Sorghum Silage for Dairy Cows as an Alternative to Irrigated Maize Silage

Under European dairy cattle rearing conditions, whole plant maize silage is the main part of the dairy cow\u27s diet especially during the winter season. Nevertheless maize production can be limited in some areas because summer rainfall is insufficient and so irrigation is necessary. Grain sorghum hybrids, and especially sweet sorghum types, are potentially of great interest to avoid this water consumption (Lemaire et al., 1996, Legarto, 2000). For this reason we evaluated in 2003 the benefits and limits of a sweet grain sorghum silage for dairy milk production, compared to an irrigated maize silage. We paid particularl attention to forage quality and yield, environmental effects and animal performance

Genetic Diversity Among Alfalfa Cultivars Using SSR Markers

Alfalfa (Medicago sativa) is an autotetraploid, allogamous and heterozygous species. Cultivated varieties are synthetic cultivars, usually obtained through 3 or 4 generations of panmictic reproduction of a set of various numbers of parents. The parents can be clones, half-sib or full-sib families. The breeders apply selection pressure for some agronomic traits, to induce changes in the genetic background. The objective of this study was to investigate the differentiation level among seven cultivars originating from one breeding program, and between these cultivars and the breeding pool, with eight SSR markers

Association study between the gibberellic acid insensitive gene and leaf length in a Lolium perenne L. synthetic variety

<p>Abstract</p> <p>Background</p> <p>Association studies are of great interest to identify genes explaining trait variation since they deal with more than just a few alleles like classical QTL analyses. They are usually performed using collections representing a wide range of variability but which could present a genetic substructure. The aim of this paper is to demonstrate that association studies can be performed using synthetic varieties obtained after several panmictic generations. This demonstration is based on an example of association between the gibberellic acid insensitive gene (GAI) polymorphism and leaf length polymorphism in 'Herbie', a synthetic variety of perennial ryegrass.</p> <p>Methods</p> <p>Leaf growth parameters, consisted of leaf length, maximum leaf elongation rate (LERmax) and leaf elongation duration (LED), were evaluated in spring and autumn on 216 plants of Herbie with three replicates. For each plant, a sequence of 370 bp in GAI was analysed for polymorphism.</p> <p>Results</p> <p>Genetic effect was highly significant for all traits. Broad sense heritabilities were higher for leaf length and LERmax with about 0.7 in each period and 0.5 considering both periods than for LED with about 0.4 in each period and 0.3 considering both periods. GAI was highly polymorphic with an average of 12 bp between two consecutive SNPs and 39 haplotypes in which 9 were more frequent. Linkage disequilibrium declined rapidly with distance with r ²values lower than 0.2 beyond 150 bp. Sequence polymorphism of GAI explained 8-14% of leaf growth parameter variation. A single SNP explained 4% of the phenotypic variance of leaf length in both periods which represents a difference of 33 mm on an average of 300 mm.</p> <p>Conclusions</p> <p>Synthetic varieties in which linkage disequilibrium declines rapidly with distance are suitable for association studies using the "candidate gene" approach. GAI polymorphism was found to be associated with leaf length polymorphism which was more correlated to LERmax than to LED in Herbie. It is a good candidate to explain leaf length variation in other plant material.</p

Miocene (23–13 Ma) continental paleotemperature record from the northern Mediterranean region (Digne-Valensole Basin, SE France) within a global climatic framework

During the Middle Miocene, the Earth’s climate transitioned from a warm phase, the Miocene Climatic Optimum (MCO, 16.9–14.7 Ma), to a colder phase associated by formation of major ice sheets on Antarctica. This climatic shift, the Middle Miocene Climatic Transition (MMCT, 14.7–13.8 Ma), considerably impacted not only the structure and formation of major ecosystems (e.g. Jimenez-Moreno & Suc, 2005) it also affected global ocean circulation (Holbourn et al., 2014), terrestrial temperatures as well as precipitation patterns (e.g. Methner et al., 2020). While the MCO and the subsequent MMCT are well described in marine records, knowledge about the magnitude and rate of terrestrial paleoclimate changes is often limited by lack of temporal resolution and reliable quantitative proxy records (Steinthorsdottir et al., 2021). Here, we present a long-term (23–13 Ma) biostratigraphically-controlled terrestrial stable (δ18O, δ13C) and clumped (Δ47) isotope paleosol carbonate record from the northern Mediterranean region (Digne-Valensole basin, SE France). When comparing the northern Mediterranean δ18O, δ13C and Δ47 record with age-equivalent counterparts from central Europe (Northern Alpine Foreland Basin, Switzerland), our Δ47 results from the Digne-Valensole basin reveal two important features: 1) Relatively warm and constant carbonate formation temperatures (ca. 30°C) for the Early Miocene (23–18.6 Ma) followed by 2) intensified temperature fluctuations with high values (ca. 37°C) at the onset of the MCO, most probably amplified by changes in seasonality of pedogenic carbonate formation. The combined Northern Alpine foreland and northern Mediterranean records display a coherent climate pattern for the Middle Miocene circum-Alpine foreland. In both records, high-amplitude, rapid changes in Δ47 temperatures (ca. 18°C within 400 ka) characterize the onset of the MCO and MMCT. We furthermore identify warm peaks during the MCO and a distinct fall in apparent Δ47-based temperatures at ca. 14 Ma that is in very good temporal agreement with oceanic isotope records and coincides with the documented global cooling following the MCT. Collectively, these data contribute to understanding of the dynamics and variability in atmospheric circulation controlling Middle to Late Miocene temperature dynamics in the Northern Mediterranean region

Depth-Dependent Compressive Equilibrium Properties of Articular Cartilage Explained by Its Composition,” Biomech.

Abstract For this study, we hypothesized that the depthdependent compressive equilibrium properties of articular cartilage are the inherent consequence of its depth-dependent composition, and not the result of depth-dependent material properties. To test this hypothesis, our recently developed fibril-reinforced poroviscoelastic swelling model was expanded to include the influence of intra-and extra-fibrillar water content, and the influence of the solid fraction on the compressive properties of the tissue. With this model, the depth-dependent compressive equilibrium properties of articular cartilage were determined, and compared with experimental data from the literature. The typical depth-dependent behavior of articular cartilage was predicted by this model. The effective aggregate modulus was highly strain-dependent. It decreased with increasing strain for low strains, and increases with increasing strain for high strains. This effect was more pronounced with increasing distance from the articular surface. The main insight from this study is that the depth-dependent material behavior of articular cartilage can be obtained from its depth-dependent composition only. This eliminates the need for the assumption that the material properties of the different constituents themselves vary with depth. Such insights are important for understanding cartilage mechanical behavior, cartilage damage mechanisms and tissue engineering studies