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Marginal populations of animals are highly susceptible to environmental pressures associated with climatic changes. Understanding their distribution and ecological requirements is, thus, essential for the development of efficient conservation strategies. The dice snake, Natrix tessellata, is listed as critically endangered in the Czech Republic. In certain regions (Bohemia and Silesia), its populations are located beyond the northern border of the continuous range of the species, while the south Moravian populations are connected to it. Based on the statewide database of the Czech Nature Conservation Agency, we created a predictive model and determined key factors influencing the species distribution. The most relevant factors were: watercourses and bodies, average annual temperatures, altitude, slope inclination and precipitation seasonality. The model fits thepresence records well and is applicable in both theory and practice of the species conservation - for example, focusing faunistic research to certain areas, critical analysis of controversial presence reports and as an input for species management in the form of repatriation and introduction. [ABSTRACT FROM AUTHOR]

Reproductive isolation barriers maintain the integrity of species by preventing interspecific gene flow. They involve temporal, habitat or behavioral isolation acting before fertilization, and postzygotic isolation manifested as hybrid mortality or sterility. One of the approaches of how to study reproductive isolation barriers is through the analysis of hybrid zones. In this paper, we describe the structure of a hybrid zone between two crested newt species (Triturus cristatus and T. carnifex) in the southern part of the Czech Republic using morphological, microsatellite, and mitochondrial (mtDNA) markers. Specifically, we tested the hypothesis that the structure of the hybrid zone is maintained by species‐specific habitat preferences. Comparing the genetic structure of populations with geographical and ecological parameters, we found that the hybrid zone was structured primarily geographically, with T. cristatus‐like populations occurring in the northeast and T. carnifex‐like populations in the southwest. Despite T. cristatus tending to occur in deeper ponds and T. carnifex on localities with more shading, the effect of both ecological parameters on the structure of the zone was minimal. Next, we corroborated that T. carnifex individuals and some hybrids possess mtDNA of T. dobrogicus, whose nuclear background was not detected in the studied hybrid zone. Hybridization between T. carnifex and T. dobrogicus (resulting in unidirectional mtDNA introgression) had to predate subsequent formation of the hybrid zone between T. cristatus and T. carnifex. Populations of crested newts in the southern part of the Czech Republic thus represent a genetic mosaic of nuclear and mitochondrial genomes of three species. [ABSTRACT FROM AUTHOR]

Morphological abnormalities occur frequently in wild amphibian populations. We analysed malformation and injuries in the hybrid zone of three crested newt species, in the Czech Republic. In total, 274 individuals from 35 localities in South Moravia (Czech Republic) were examined during the period 2010-2014. Malformations were found in eight newts (2.9%) from seven localities. Injuries were recorded on 59 newts (21.5%). Proportions of tail crest injuries was significantly higher (P < 0.1) in males than in females and the probability of being injured was significantly higher (P <0.01) for adult individuals. We discuss gene mutation, parasitism and predation as possible explanations for our observations. [ABSTRACT FROM AUTHOR]

The article discusses deformable-object simulators in the context of surgical simulation. It is noted that computer graphics applications which mimic the deformation of soft tissue by surgical instruments in real time often suffer from stability problems. These are said to be caused by material slivers in the cut vicinity. A method for avoiding this problem is described. Known as the extended finite element method (XFEM), it provides discontinuity modeling using element enrichment, which is said to produce stable simulations when combined with a mass-lumping approach.

In this paper we present a novel approach for stable interactive cutting of deformable objects in virtual environments. Our method is based on the extended finite elements method, allowing for a modeling of discontinuities without remeshing. As no new elements are created, the impact on simulation performance is minimized. We also propose an appropriate mass lumping technique to guarantee for the stability of the simulation regardless of the position of the cut. [ABSTRACT FROM AUTHOR]