Environmental conditions affecting spiders in grasslands at the lower reach of the River Tisza in Hungary

The aims of the present study were to reveal the differences between grassland types, and to identify the local and landscape parameters that influence the spider assemblages at the reach of the River Tisza. The rarefied number of spider species was negatively correlated with the proportion of forests in a radius of 500 m around each site. A negative correlation was found between the number of grassland specialist species and the proportion of the forests, but the number of forest species increased significantly with the neighboring forest area. The relative area of neighboring forests, the number of plant species and regular flooding played major roles in shaping of the species composition of spiders. The results of the present study emphasize the importance of the effect of habitat landscape properties on spider assemblages. The structural diversity of the landscape may influence species richness and composition of the habitats

Electrical cross-talk in four-electrode experiments

The subject of this paper is electrical cross-talk, an interference between the current/voltage characteristics of the two working electrodes in four-electrode (generator/collector) systems. Cross-talk arises in electrochemical cells of finite resistance due to the superposition of the electrical fields of the working electrodes, and often causes difficulties in the interpretation of measurement results. In this paper, we present an algorithm for modelling simple generation/collection experiments with a rotating ring–disk electrode (RRDE) immersed into a finite resistance solution of a redox couple. We show that based on the analysis of the Kirchhoff (Laplace) matrix of the simulation mesh, the effect of electrical cross-talk may be accounted for in such experiments. The intensity of cross-talk is found to be heavily influenced by the selection of the reference point for potential measurements; in practice, this is the position of the reference electrode or the tip of the Luggin probe. The devised model is validated by means of a simple and demonstrative experiment