Molecular Realism in Default Models for Information Theories of Hydrophobic Effects

This letter considers several physical arguments about contributions to hydrophobic hydration of inert gases, constructs default models to test them within information theories, and gives information theory predictions using those default models with moment information drawn from simulation of liquid water. Tested physical features include: packing or steric effects, the role of attractive forces that lower the solvent pressure, and the roughly tetrahedral coordination of water molecules in liquid water. Packing effects (hard sphere default model) and packing effects plus attractive forces (Lennard-Jones default model) are ineffective in improving the prediction of hydrophobic hydration free energies of inert gases over the previously used Gibbs and flat default models. However, a conceptually simple cluster Poisson model that incorporates tetrahedral coordination structure in the default model is one of the better performers for these predictions. These results provide a partial rationalization of the remarkable performance of the flat default model with two moments in previous applications. The cluster Poisson default model thus will be the subject of further refinement.Comment: 5 pages including 3 figure

The effect of within-crop habitat manipulations on the conservation biological control of aphids in field-grown lettuce

Within-crop habitat manipulations have the potential to increase the biological control of pests in horticultural field crops. Wildflower strips have been shown to increase the abundance of natural enemies, but there is little evidence to date of an impact on pest populations. The aim of this study was to determine whether withincrop wildflower strips can increase the natural regulation of pests in horticultural field crops. Aphid numbers in plots of lettuce grown adjacent to wildflower strips were compared with those in plots grown in the absence of wildflowers. The presence of wildflower strips led to a decrease in aphid numbers on adjacent lettuce plants during June and July, but had less impact in August and September. The decrease in aphid numbers was greatest close to the wildflower strips and, the decrease in aphid numbers declined with increasing distance from the wildflower strips, with little effect at a distance of ten metres. The main natural enemies found in the crop were those that dispersed aerially, which is consistent with data from previous studies on cereal crops. Analysis and interpretation of natural enemy numbers was difficult due to low recovery of natural enemies, and the numbers appeared to follow changes in aphid abundance rather than being directly linked to the presence of wildflower strips. Cutting the wildflower strips, to remove floral resources, had no impact on the reduction in aphid numbers achieved during June and July, but decreased the effect of the wildflower strips during August and September. The results suggest that wildflower strips can lead to increased natural regulation of pest aphids in outdoor lettuce crops, but more research is required to determine how this is mediated by natural enemies and how the impact of wildflower strips on natural pest regulation changes during the growing season

Summary of sand waves and regimes of flow in alluvial channels

CER60MLA24.Includes bibliographical references

Loup et forêt méditerranéenne, quelles questions pour l'élevage et la gestion de l'espace ?

Le retour du loup dans les Alpes françaises représente une contrainte lourde pour les systèmes pastoraux. Or la prédation ne concerne pas seulement les alpages de haute montagne, elle se développe aussi dans des montagnes boisées de l'arrière pays méditerranéen. Le travail effectué chez les éleveurs concernés a permis de mettre en évidence des facteurs particuliers de vulnérabilité face à la prédation en Préalpes méditerranéennes : risque important de prédation au pâturage en quartier boisé, risque spécifique en fin d'automne et en hiver, vulnérabilité particulière des points d'eau naturels ; enfin risque lié au pâturage en parcs clôturés, qui s'est particulièrement développé dans l'arrière-pays méditerranéen, notamment pour l'entretien des grandes coupures DFCI. Les solutions envisageables sont très partielles et se traduisent par un réaménagement structurant à l'échelle de l'ensemble des unités pastorales concernées (déboisement, impluviums, cabanes), en plus des outils de protection actuellement développés (et en particulier le chien de protection)

Adiciones a la flora navarra.

Se dan a conocer nuevas localidades navarras para 48 especies de fanerógamas, 20 de las cuales se citan por primera vez para la provincia

Damasonium alisma Miller, novedad para el catálogo florístico navarro.

Se cita Damasonium alisma Miller, herborizada en Montiuso, término de Lerín, como novedad para el catálogo florístico de la provincia de Navarra