The aim of this study was to characterize karyotypes of central European spiders of the genera Arctosa, Tricca, and Xerolycosa (Lycosidae) with respect to the diploid chromosome number, chromosome morphology, and sex chromosomes. Karyotype data are reported for eleven species, six of them for the first time. For selected species the pattern in the distributions of the constitutive heterochromatin and the nucleolar organizer regions (NORs) was determined. The silver staining technique for detecting NORs of lycosid spiders was standardized. The male karyotype consisted of 2n = 28 (Arctosa and Tricca) or 2n = 22 (Xerolycosa) acrocentric chromosomes. The sex chromosome system was X1X20 in all species. The sex chromosomes of T. lutetiana and X. nemoralis showed unusual behaviour during late diplotene, namely temporary extension due to decondensation. C-banding technique revealed a small amount of constitutive heterochromatin at the centromeric region of the chromosomes. Two pairs of autosomes bore terminal NORs. Differences in karyotypes among Arctosa species indicate that the evolution of the karyotype in this genus involved autosome translocations and size changes in the sex chromosomes. Based on published results and those recorded in this study it is suggested that the ancestral male karyotype of the superfamily Lycosoidea consisted of 28 acrocentric chromosomes. and Petr DOLEJŠ, Tereza KOŘÍNKOVÁ, Jana MUSILOVÁ, Věra OPATOVÁ, Lenka KUBCOVÁ, Jan BUCHAR, Jiří KRÁL.
This short contribution presents six papers, which characterize research areas at the Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University. The joint research field is the interaction between particles, and particle interaction with gases, solid structures, and surfaces. in particular, the research concerns vacuum physics, physics of thin films and surfaces, plasma physics, and space physics together with their applications in diagnostics and modern technologies in material science., Jana Šafránková, Jan Wild., and Obsahuje bibliografii
The ongoing development of landslide prone regions increases future potential losses caused by landslide occurrence. The first step towards landslide mitigation on a regional scale is a susceptibility assessment. This study focuses on the area surrounding the regional capital of Zlín, in the Outer Western Carpathians. The city is located in the flysch highlands. Statistical analysis of the distribution of landslide scarps was undertaken in relation to various preparatory factors (geology, slope angle, slope aspect, slope curvature, distance from closest stream). This analysis provided insights into the main initiating factors and allowed our results to be compared with other studies in similar regions. Thereafter, a regional landslide susceptibility assessment was undertaken. The model performance was evaluated with respect to the landslide information used during its preparation and with a separate validation dataset. The results show that the main predisposing factors are the claystone rich bedrock unit, thick accumulations of slope sediments, and slope angles between 10° and 15°. The possible application of the presented results for urban planning purposes is also outlined., Jan Klimeš and Roman Novotný., and Obsahuje bibliografii
We first recall the main features of Mach's radical attitude to the "philosophy of science", illustrated best by his criticism of absolute space and time, and discuss the impact of Mach's ideas on the birth of special and general relativity. The experiment to demonstrate "Machian effects" of dragging of inertial frames by a rotating body (carried out by four gyroscopes placed in an orbit around the Earth) was conceived in 1959 but only in 2014 was the satellite launched. The last results from the experiment were finally summarised at the end of 2015: they confirm the dragging as predicted by general relativity with an accuracy of 19 %. We show that a rotating black hole can even drag magnetic field lines and indicate possible astrophysical meaning of processes of this type. in the concluding parts, our investigation of dragging effects by gravitational waves and the study of Mach's principle in the context of cosmology, obtained in collaboration with Donald Lynden-Bell (Cambridge) and Joseph Katz (Jerusalem), are briefly reviewed., Jiří Bičák., and Obsahuje bibliografii