Why phylogenetic signal of traits is important in ecosystems: uniformity of a plant trait increases soil fauna, but only in a phylogenetically uniform vegetation.

Phylogenetically closely related plant species often share similar trait states (phylogenetic signal), but local assembly may favor dissimilar relatives and thereby decouple the diversity of a trait from the diversity of phylogenetic lineages. Associated fauna might either benefit from plant trait diversity, because it provides them complementary resources, or suffer from it due to dilution of preferred resources. We hence hypothesize that decoupling of trait and phylogenetic diversity weakens the relationship between the plant-trait diversity and the abundance and diversity of associated fauna. Studying permanent meadows, we tested for combined effects of plant phylogenetic diversity and diversity of two functional traits (specific leaf area, leaf dry matter content) on major groups of soil fauna (earthworms, mites, springtails, nematodes). We found that only in phylogenetically uniform plant communities, was uniformity in the functional traits associated with (i) high abundance in springtails, and (ii) high abundance of the sub-group that feeds more directly on plant material (in springtails and mites) or those that are more prone to disturbance (in nematodes), and (iii) high diversity in all three groups tested (springtails, earthworms, nematodes). Our results suggest that soil fauna profits from the resource concentration in local plant communities that are uniform in both functional traits and phylogenetic lineages. Soil fauna would hence benefit from co-occurrence of closely related plants that have conserved the same trait values, rather than of distantly related plants that have converged in traits. This might result in faster decomposition and a positive feedback between trait conservatism and ecosystem functioning.

Properties and microstructure of thermo-pressed wheat gluten films: a comparison with cast films.

Wheat gluten films were prepared by thermo-pressing, and their mechanical properties were compared to those of cast films. The stress-strain relationship was established for films with various amounts of glycerol. Both relationships were quite different, revealing a different network organization. Thermo-pressed films presented higher stress values than cast films, but the effect of the glycerol amount was similar in both cases, an increase of the glycerol amount leading to a decrease of both films stress. The glycerol influence on the strain at break of thermo-pressed films was very limited, with strain values reaching a maximum around 200%. The role of disulfide bridges on themomoulded films mechanical properties was investigated, and it was shown that some rearrangements and a significative protein insolubilization occurred during the process. The effective flow porosity of the protein network for thermo-pressed films was estimated by water capillary rise measurements to about 7%. Scanning electron microscopy was used to obtain some information about the microstructure of both cast and thermo-pressed films.

Effects of shear on two microalgae species. Contribution of pumps and valves in tangential flow filtration systems.

The circulation of microorganisms in tangential flow filtration systems induces perturbations and then the damage of brittle cells. This work is focused on the shearing of two marine microalgae species (Skeletonema costatum and Haslea ostrearia), both largely cultivated in western France (Région des Pays de la Loire). We have studied the effects of the circulation of these cells in pumps and valves. For the pumps, it is shown that shear stress is due to the type of pump, but that mechanical shear can have different effects even if the pumps and the number or frequency of loops are the same. Hence other intrinsic parameters of the pump must be taken into account: rotating velocity (omega), capacity (Cyl = output flow/rotating velocity) or internal leakage (K = inner volume/capacity). In throttling valves, the aim is to correlate the effect of shear to a parameter related to the inner geometry of the valve and to operating conditions. An overall parameter is then evaluated: the pressure drop coefficient Kv which integrates both the type of valve (ball valve or globe valve type) and its opening degree. Kv is derived from the relationship DeltaH = Kvu2/2g. The modelling of the shear effects is now conceivable: basic descriptive data used so far (type of pump, geometry or opening degree of the valve, etc.) being completed and partially substituted by quantitative parameters (rotating velocity, capacity, or internal leakage for the pumps, Kv coefficient for the valves).

Immunity levels against avian encephalomyelitis in vaccinated poultry breeder flocks in Maine.

Four commercial poultry breeder flocks that were vaccinated under field conditions against avian encephalomyelitis (AE) with commercial live or inactivated vaccine were monitored periodically by virus-neutralization testing of blood serum samples and by challenge of their progeny eggs and chicks. The history of the flocks and results of the tests indicate that field exposure might occur during the laying period, thereby boosting immunity titers without causing clinical AE in the progeny chicks. The data also indicate field exposure of certain flocks before AE vaccination.