A Posteriori Error Estimates for Nonconforming Approximations of Evolutionary Convection-Diffusion Problems

We derive computable upper bounds for the difference between an exact solution of the evolutionary convection-diffusion problem and an approximation of this solution. The estimates are obtained by certain transformations of the integral identity that defines the generalized solution. These estimates depend on neither special properties of the exact solution nor its approximation, and involve only global constants coming from embedding inequalities. The estimates are first derived for functions in the corresponding energy space, and then possible extensions to classes of piecewise continuous approximations are discussed.Comment: 10 page

Parasites of the Deep-Sea Smelt Bathylagus euryops (Argentiniformes: Microstomatidae) from the Charlie-Gibbs Fracture Zone (CGFZ)

The deep-sea smelt Bathylagus euryops, caught in July 2004 at the Charlie-Gibbs Fracture Zone (CGFZ) of the Mid-Atlantic Ridge (North Atlantic), was studied for metazoan parasites and diet composition. A total of 86 specimens with standard lengths between 6.4 and 22.1 cm (mean 13.6 cm) were examined. The parasite fauna consisted of five species: three Digenea, one Cestoda and one Nematoda. The predominant parasites were Lecithaster sp. (Digenea) and an unidentified bothriocephalidean cestode. The only nematode, Anisakis sp., occurred with a low prevalence. Bathylagus euryops at CGFZ serves as final host for the three digeneans, and as intermediate host for the cestodes and Anisakis sp. Stomach content analysis revealed a mesozooplankton crustacean diet, while 95.3% of the stomachs contained unidentified tissue

Metazoa and Related Diseases

11 pages, 6 figures.-- This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International LicenseCephalopods and their metazoan parasites have coevolved in wild fisheries for many years. In fact, helminth larvae and parasitic copepods have been recorded in cephalopods worldwide. This is not surprising considering the important role cephalopods play in the transfer of energy and contaminants in marine food webs. Nerito-oceanic ommastrephid squids are by far the most noticeable trophic bridge for helminth parasites in the marine realm, coastal octopus, and cuttlefish serving as primary host for crustaceans. Although it is highly likely that parasitic infections occurred, relatively little is known about the pathogenic potential of metazoan parasites in naturally infected cephalopods. It is stated that heavy parasitic infections may probably cause host morbidity or poor condition but signs of disease are singularly rare with very few specimens exhibiting disease conditions. Unfortunately, neither robust scientific evidence nor available material is available to support this statement. It is more likely that metazoans may deplete energy stores of infected cephalopods, which are directed toward tissue repair and the host’s defense mechanisms. Parasitic infection may thus be considered an environmental stressor and as such a source of uncertainty in the evaluation of the potential productivity of cephalopod populationsPeer reviewe