This paper describes the first study of the diatom assemblages in caves in the Czech Republic. The study focused on subaeric habitats: rock faces within caves, walls at cave entrances and “lampflora” assemblages, in three cave systems, Mladeč, Javoříčko and Zbrašov, all in central Moravia. The morphological and cytological variability, ecology and life strategies of diatoms were studied in fresh samples, in Naphrax preparations, in cultures grown on agar plates and in monoclonal cultures. A total of 22 diatom species was identified, mostly aerophytic species and tolerant of low light intensities. Luticola and Diadesmis species complexes are discussed. Taxa D. gallica and L. paramutica var. binodis are new for the Czech Republic. Sexual reproduction was observed in L. mutica and Orthoseira roeseana.
Only in the southern part of the Iberian Peninsula the large white butterfly Pieris brassicae was recorded to pass the summer in pupal aestivation, induced by long-day photoperiods. It is not clear why this photoperiodic response is regionally restricted. We investigated whether the change of life history in P. brassicae may affect the infestation by parasites. This was done by testing the coincidence of photoperiodic responses in both the host P. brassicae and in its main parasitoid Cotesia glomerata. While the response under short-day conditions was very similar in both species, no summer dormancy of any type was found in the parasitoid at photophases >= 15h and temperatures of 15°-25°C in contrast to 100% aestivation in the host. We suggest that aestivation is a response which allows the host to desynchronise its life cycle from that of its parasitoid. This is effective because parasitoid wasps cannot pass the temporary absence of suitable host stages by a similar developmental rest. C. glomerata is then forced to switch to less adequate host species which diminishes its reproductive success.
The paper studies applications of C*-algebras in geometric topology. Namely, a covariant functor from the category of mapping tori to a category of AF-algebras is constructed; the functor takes continuous maps between such manifolds to stable homomorphisms between the corresponding AF-algebras. We use this functor to develop an obstruction theory for the torus bundles of dimension 2, 3 and 4. In conclusion, we consider two numerical examples illustrating our main results., Igor Nikolaev., and Obsahuje seznam literatury
In this paper it is proved that an abelian lattice ordered group which can be expressed as a nontrivial lexicographic product is never affine complete.
Let $\Delta $ and $H$ be a nonzero abelian linearly ordered group or a nonzero abelian lattice ordered group, respectively. In this paper we prove that the wreath product of $\Delta $ and $H$ fails to be affine complete.
Identities for the curvature tensor of the Levi-Cività connection on an almost para-cosymplectic manifold are proved. Elements of harmonic theory for almost product structures are given and a Bochner-type formula for the leaves of the canonical foliation is established.
It is shown that under the name Mocis frugalis (F., 1775), considered to represent a widespread pest of graminaceous crops in the Eastern hemisphere and the Pacific, two species have been hitherto confused. Populations from Africa and Arabian Peninsula are described as Mocis proverai sp. n. The main characters which distinguish the African-Arabian M. proverai from M. frugalis of Asia and the Pacific are found in the genitalia, especially the configuration of the male vesica and female bursa copulatrix.