Morphological separation of the Central European Trochosa females (Araneae, Lycosidae)

Adult females of the five Central European wolf spiders Trochosa hispanica Simon, 1870, T. robusta (Simon, 1876), T. ruricola (De Geer, 1778), T. spinipalpis (F. O. P.-Cambridge, 1895), and T. terricola Thorell, 1856 were morphologically analysed. We defined sets of continuous and binary (presence/absence) variables. Continuous data of various epigynal and carapace dimensions were subjected to Principal Components Analysis (PCA). Using the PC loadings each individual was plotted along the PC axis in order to find gaps/overlaps between the species. The binary data sets were subjected to Hierarchical Cluster Analysis (HCA) in order to find characters that clearly separate the five Trochosa species. Using PCA only individuals of T. robusta and T. ruricola and of T. robusta and T. hispanica could be separated from each other. Using HCA all five species could clearly be separated by epigynal and vulval characteristics

A new feature for the separation of Trochosa spinipalpis and T. terricola males (Araneae, Lycosidae)

A new feature on the tip of the palp, which enables the separation of male Trochosa spinipalpis (F. O. P.-Cambridge, 1895) from T. terricola Thorell, 1856, is described. T. terricola exhibits a hairless strip on the tip of the palp, while T. spinipalpis lacks this feature and has long hairs on the whole palp

Nonlinear buckling and symmetry breaking of a soft elastic sheet sliding on a cylindrical substrate

We consider the axial compression of a thin sheet wrapped around a rigid cylindrical substrate. In contrast to the wrinkling-to-fold transitions exhibited in similar systems, we find that the sheet always buckles into a single symmetric fold, while periodic solutions are unstable. Upon further compression, the solution breaks symmetry and stabilizes into a recumbent fold. Using linear analysis and numerics, we theoretically predict the buckling force and energy as a function of the compressive displacement. We compare our theory to experiments employing cylindrical neoprene sheets and find remarkably good agreement.Comment: 20 pages, 5 figure

Impact of the CAP Reform on Small-Scaled Grassland Regions in Bavaria, Germany

The CAP reform of 2003 will change farmer's business environment in Europe. This paper analyses the impact of the reform on the land use in southern German grassland regions. The assessment will be based on model calculations for two typical grassland regions. Each study area represents one village with its specific farm structure and natural conditions. These regions differ in their excellence with respect to agricultural use. In Southern Germany small to medium sized family farms is the most frequent type of farming. We use a regional land-use model that conceives farms as independent agents aiming at maximum individual utility. Farm agents optimize their farm organisation with the help of a linear-programming algorithm that takes into account natural, economic and personal restrictions. Interactions between farms take place on the land market, which is modelled as an equilibrium market. It becomes clear that the CAP reform of 2003 has various significant consequences with respect to grassland use. In particular the decreasing profitability of dairy farming will relatively promote low-intensive forms of grassland use, including mulching. If some payments (e. g. agri-environmental payments) remain coupled to livestock production area-wide agriculture can be maintained even in marginal areas. Land rents will generally increase in more marginal areas due to the effects of decoupling.CAP-reform, linear programming, land-market simulation, agent-based modelling, farmers attitude, policy analysis, Agricultural and Food Policy,