An electrothermal instability: the influence of albedo boundary conditions on the stationary states of an exactly solvable model

In order to study the effect of partially reflective (albedo) boundary conditions on pattern formation and stability in reaction-diffusion systems, we have analyzed an exactly soluble model of an electrothermal instability: the Ballast resistor. The present results allow a continuous interpolation between the results corresponding to Neumann and Dirichlet boundary conditions, and they allow qualitative changes in the patterns to be followed.     

Imposex and organotin body burden in the dog‐whelk (Nucella lapillus L.) along the Portuguese coast

Nucella lapillus imposex—superimposition of male characters onto prosobranch (a subclass of gastropod molluscs) females—and organotin female body burden were surveyed on the Portuguese coast, from Vila Praia de Âncora (northern limit) to Praia da Luz (southern limit), at 17 sampling stations, between May and August 2003. The vas deferens sequence index (VDSI), the relative penis size index (RPSI), the percentage of females affected with imposex (%I) and the percentage of sterile females (%S) were used to assess the level of imposex at each site. VDSI, RPSI and %I were 0.20–4.04, 0.0–42.2% and 16.7–100.0%, respectively. Sterile females were found at stations 2 (6.2%), 5 (4.0%) and 7 (5.0%). Tributyltin (TBT) and dibutyltin (DBT) female body burdens were 23–138 and <10–62 ng Sn/g dry weight, respectively. TBT female body burden was significantly correlated with RPSI and VDSI [Spearman rank order linear correlation: RPSI vs TBT body burden (b.b.) r = 0.71, p < 0.01; VDSI vs logTBT body burden r = 0.71, p < 0.01]. Imposex and TBT b.b. were highest at sites located in the proximity of harbours, where TBT leaching from antifouling paints is more intense owing to the high concentration of ships and dockyard activities. Copyright © 2005 John Wiley & Sons, Ltd.     

Some results on polarized partion relations of higher dimension

Several types of polarized partition relations are considered. In particular we deal with partitions defined on cartesian products of more than two factors. MSC: 03E05.     

Characterization of a protease produced by a Trichoderma harzianum isolate which controls cocoa plant witches' broom disease

Background  

Several Trichoderma strains have been reported to be effective in controlling plant diseases, and the action of fungal hydrolytic enzymes has been considered as the main mechanism involved in the antagonistic process. However, although Trichoderma strains were found to impair development of Crinipellis perniciosa, the causal agent of cocoa plant witches' broom disease, no fungal strain is available for effective control of this disease. We have then undertaken a program of construction of hydrolytic enzyme-overproducing Trichoderma strains aiming improvement of the fungal antagonistic capacity. The protease of an indian Trichoderma isolate showing antagonistic activity against C. perniciosa was purified to homogeneity and characterized for its kinetic properties and action on the phytopathogen cell wall.     

Isoparametric families of submanifolds

An extension of Cartan's theory of isometric families of hypersurfaces is presented. The leaves of the new families are submanifolds of higher codimension. It is proved that the leaves have mean curvature vector with constant norm. If the distribution defined by the normal spaces of the leaves is integrable, the theory can be developed along the same lines as in the usual case (i.e. families of hypersurfaces). These families are thus obtained constructing “parallel” submanifolds. A generalization of Cartan's fundamental formula is obtained and a simple geometrical application of it is given.