Non-liftable Calabi-Yau spaces

We construct many new non-liftable three-dimensional Calabi-Yau spaces in positive characteristic. The technique relies on lifting a nodal model to a smooth rigid Calabi-Yau space over some number field as introduced by the first author and D. van Straten.Comment: 16 pages, 5 tables; v2: minor corrections and addition

Assessment of environmental hazards in the north western coast -Egypt using RS and GIS

AbstractSoil erosion, salinity and sodicity hazards are serious problems in the northern west coast of Egypt and lead to reducing the soil quality and increasing the degradation of soil resources. Sidi Barrani and Al-Sallum regions are selected as study areas which are located from a longitude of 25°10′00″ to 26°55′00″East and from a latitude of 31°00′0″ to 31°37′30″ North. Erosion hazard was estimated using the ‘Universal Soil Loss Equation’ (USLE), which is a simple empirical model that is widely used for assessing long-term annual soil loss .The salinity and sodicity hazards were estimated based on FAO method as standard reference. The resultant map of annual soil erosion shows a maximum soil loss of 60th−1y−1with a close relation to foot slopes and wide units on the steep side-slopes (with high LS value) and the erodibility value reached to 0.1th−1y−1. Meanwhile sand beaches and sabkha units are characterized by high environmental hazards of both water erosion, salinity and sodicity, while in the overflow basin units are identified as low environmental hazards. The spatial environmental hazards assessment is conducted by using integrated GIS and RS which can serve as effective inputs in deriving strategies for sustainable land use planning and management

New records of the great raft spider Dolomedes plantarius in Brandenburg (Araneae: Pisauridae)

The great raft spider, Dolomedes plantarius (Clerck, 1757), is a rare and endangered species in Germany and other European countries. Current data on its distribution and ecology are briefly reviewed. Five new (or overlooked) localities for this spider from the Spreewald-region of Brandenburg in eastern Germany are provided, together with an updated distribution map. One record, based on the authors’ own collections, is described and figured in detail, with the egg-carrying female discovered in reeds at the edge of a fairly large body of open water. Both direct and indirect protective measures for the habitats of this species in the Spreewald-region are recommended