Snow cover thickness estimation using radial basis function networks

Abstract. This paper reports an experimental study designed for the in-depth investigation of how the radial basis function network (RBFN) estimates snow cover thickness as a function of climate and topographic parameters. The estimation problem is modeled in terms of both function regression and classification, obtaining continuous and discrete thickness values, respectively. The model is based on a minimal set of climatic and topographic data collected from a limited number of stations located in the Italian Central Alps. Several experiments have been conceived and conducted adopting different evaluation indexes. A comparison analysis was also developed for a quantitative evaluation of the advantages of the RBFN method over to conventional widely used spatial interpolation techniques when dealing with critical situations originated by lack of data and limited n-homogeneously distributed instrumented sites. The RBFN model proved competitive behavior and a valuable tool in critical situations in which conventional techniques suffer from a lack of representative data

A hedgehog-like signal is involved in slow muscle differentation in Sepia officinalis (Mollusca)

In the tentacle of Sepia officinalis, smooth-like, helical and cross-striated fibres deriving from different populations of myoblasts are present. Myoblasts appear at different times during the development and express two muscle-specific transcription factors: Myf5-like and MyoD-like factors. Myoblasts expressing Myf5 give rise to slow fibres, whereas fast fibres derive from MyoD+ myoblasts. We found that a Hedgehog (Hh)-like signal was present in the central nerve cord of the tentacle from the early stages of development and in a specific population of myoblasts which are the precursors of slow muscle fibres. The model showed interesting similarities with vertebrates, in which Sonic hedgehog is a protein secreted by axial structures (the notochord and neurotube) and is involved in slow muscle differentiation and in survival of muscle precursors

Seasonal and geographic differences in the diet of the Barn Owl in an agro-ecosystem in northern Italy

Volume: 35Start Page: 240End Page: 24

Between land abandonment and agricultural intensification : habitat preferences of Red-backed Shrikes Lanius collurio in low-intensity farming conditions

Capsule: The conservation of Red-backed Shrikes on farmland habitats depends on extensive farming conditions. Aims: To evaluate breeding density and habitat preferences of the declining Red-backed Shrike and relate its occurrence to an environmental gradient ranging from land abandonment to intensive farming. Methods: The study was carried out in the Apennines (northern Italy), at nine 21-ha study plots. We identified factors affecting breeding density and habitat preferences at two spatial scales (landscape and territory) and analysed the variation in territory density according to the relative farming intensity in a low-intensity agricultural landscape. Results: The presence of shrubs and cultivated/grazed land positively influenced the number of Red-backed Shrike territories per plot, while the species' settlement within plots was related to higher values of shrub cover and the presence of hedges. Shrike occurrence was associated with land-use categories intermediate between land abandonment and intensive agriculture. Conclusions: This study provides a first detailed assessment of Red-backed Shrike habitat requirements in southern Europe. Favoured habitats were pasture/cultivation mosaics flanked by or interspersed with shrubs/hedges (15-20% of the surface of the 1-ha medium-sized territory). Thus, the conservation of Red-backed Shrikes in low-intensity southern European farmland appears to reflect a trade-off between agricultural intensification and long-term land abandonment