We apply a traditional method of surface wave tomography as a new approach to investigate the uppermost crust velocities in the Western Bohemia region (Czech Republic). It enables us to look for velocity distribution in a small scale of tens of kilometers. We measure Rayleigh wave group velocity dispersion curves in a period range 0.25 - 2.0 s along paths crossing the region of interest. We use modified multiple-filtering method for frequency-time analysis. We compute 2-D tomography maps of group velocity distribution in the region for eight selected periods using the standard methods and programs described in literature. We discuss the velocity distribution with respect to results of former study by Nehybka and Skácelová (1997). We present a set of local dispersion curves which may be further inverted to obtain a 3-D shear wave velocity image of the area., Petr Kolínský and Johana Brokešová., and Obsahuje bibliografické odkazy
Sarcocysts were found in muscle tissue of a wisent (Bison bonasus) which was born and kept in Germany. Light microscopic and ТЕМ examination revealed all the Ihrcc named species known from cattle: Sarcocystis cruzi („thin-walled“, with longer hairlike villar protrusions of the primary cyst wall); S. hirsuta („thick-walled“, with tongue-like protrusions of the cyst wall arising with very short and narrow stalklets from the surface of the cyst and containing rows of electron-dense granules in the core); and S. hominis („thick-walled“, with fmger-like protrusions of the cyst wall not constricted at their base and containing few or no electron-dense granules). So far, only S. cruzi was known to occur in Bison bison in North America. The findings in the wisent strikingly support a modified conception of the intermediate host specificity in Bovinae. In this connection the identity of S. cruzi and S. poephagicanis is suggested as well as that of S. hirsuta and S. poepliagi.
Needle yellowing is a typical symptom of declíning spruce trees [Picea abies (L.) Karst.] which grow at altitudes over 700 m a.s.l. In tiie chloroplasts of yellowing needles the thylakoidal systém was reduced. The contents of chlorophyll (Chl) a, b, carotene (a + |3) and neoxanthin in the needles decreased simultaneously, while lutein and the pigments of the xanthophyll cycle were less affected. Activities of the xanthophyli cycle were inhibited only in the advanced stages of yellowing. Yellowing processes with comparable symptoms could be induced in artificial atmospheres, simulating realistic conditions of pollution. Possible mechanisms accounting for the yellowing process were examined. Fast yellowing events occurred not only under full sunlight, but also imder red radiation (X > 600 ran). Therefore, the excited Chl probably sensitized pigment destruction. As the light-harvesting C\ň-a/b- protein complex of Photosystem 2 lost its photo- and acid-stability before yellowing occiured, chloroplasts were changed from a photostable to a photolabile state.