BACKGROUND This study investigates the relationship between salinity and biotic communities (primary producers and macroinvertebrates) in Rambla Salada, a Mediterranean hypersaline stream in SE Spain. Since the 1980's, the mean salinity of the stream has fallen from about 100 g L(-1) to 35.5 g L(-1), due to intensive irrigated agriculture in the watershed. Furthermore, large dilutions occur occ...

In this paper a general framework for topology optimization of structures in unilateral contact is developed. A linear elastic structure that is unilaterally constrained by rigid supports is considered. The supports are modeled by Signorini’s contact conditions which in turn are treated by the augmented Lagrangian approach as well as by a smooth approximation. The latter approximation must not ...

Snails are creatures present in various ecosystems that, in addition to being present in human surroundings, some of them are also important in veterinary medicine and medicine as the intermediate hosts of Digenean trematodes. The present study was conducted to identify and determine the geographical distribution of freshwater snails and investigate the relationship of variables, such as season...

Contact problems in computational mechanics are of significant importance for a variety of practical applications. Examples are metal forming processes, crash analysis, the design of gear boxes, bearings, car tires or implants in biomechanics. Here, we focus on Signorini’s problem in linear elasticity [10, 21, 22, 29] describing the linearized frictionless contact of an elastic body with a rigi...