The evaluation of the role of pelagic invertebrate versus vertebrate predators on the seasonal dynamics of filtering Cladocera in a shallow, eutrophic reservoir

An evaluation of the role of invertebrate (Leptodora kindtii) versus vertebrate (juvenile fish) predators in the dynamics of filtering zooplankton (Daphnia sp.) in the pelagic zone of the Sulejow Reservoir was conducted during summer from 1994 to 1996. Leptodora kindtii appeared in high densities (mid-July: 2–6 ind. l^?1) in the pelagic zone. Its predation impact on the dominant filtering zooplankter population Daphnia cucullata, expressed by consumption, was significant and accounted for a reduction of 10 to 51% of Daphnia biomass. Although D. cucullata was a preferred food of juvenile pikeperch in June, due to low biomass, these fish were able to eliminate daily only 0.1–5.4% of Daphnia biomass in the pelagic zone. Thus, the role of juvenile fish in the midsummer decline of D. cucullata density in the pelagic zone seems to be much smaller than that of Leptodora kindtii.     

Contributions of biosurfactants to natural or induced bioremediation

The number of studies dedicated to evaluating the influence of biosurfactants on bioremediation efficiency is constantly growing. Although significant progress regarding the explanation of mechanisms behind biosurfactant-induced effects could be observed, there are still many factors which are not sufficiently elucidated. This corresponds to the fact that although positive influence of biosurfactants is often reported, there are also numerous cases where no or negative effect was observed. This review summarizes the recent finding in the field of biosurfactant-amended bioremediation, focusing mainly on a critical approach towards potential limitations and causes of failure while investigating the effects of biosurfactants on the efficiency of biodegradation and phytoextraction processes. It also provides a summary of successive steps, which should be taken into consideration when designing biosurfactant-related treatment processes.     

Parallel splitting solvers for the isogeometric analysis of the Cahn-Hilliard equation

Abstract

Modeling tumor growth in biological systems is a challenging problem with important consequences for diagnosis and treatment of various forms of cancer. This growth process requires large simulation complexity due to evolving biological and chemical processes in living tissue and interactions of cellular and vascular constituents in living organisms. Herein, we describe with a phase-field model, namely the Cahn-Hilliard equation the intricate interactions between the tumors and their host tissue. The spatial discretization uses highly-continuous isogeometric elements. For fast simulation of the time-dependent Cahn-Hilliard equation, we employ an alternating directions implicit methodology. Thus, we reduce the original problems to Kronecker products of 1?D matrices that can be factorized in a linear computational cost. The implementation enables parallel multi-core simulations and shows good scalability on shared-memory multi-core machines. Combined with the high accuracy of isogeometric elements, our method shows high efficiency in solving the Cahn-Hilliard equation on tensor-product meshes.     

A new genus and species of scorpionfly (Mecoptera) from Baltic amber,with an unusually developed postnotal organ

A new genus and species of fossil scorpionflies (Mecoptera) Baltipanorpa damzeni gen. et sp.n. is described from two well‐preserved male specimens in Baltic amber (middle Eocene: Lutetian). The most characteristic feature of the new taxon is an unusually developed postnotal organ on abdominal tergum IV. This is the most extremely developed example of this organ among Mecoptera and the only observation of notal and postnotal organs among fossil scorpionflies. The following combination of characters are provided to distinguish the new genus from other Panorpidae: Sc, short; R₁ and R₂ two‐branched; A₁ joins posterior margin of wing only at same level as fork of vein Rs; unusual shape of abdomen, abdominal segments I–IV strongly reduced, abdominal segment V elongate and widened, segments VII and VIII strongly elongate; notal and postnotal organs present, strongly developed process (postnotal organ) on tergum IV, unknown in all described extant and fossil scorpionflies. Different types of notal organs of Mecoptera are compared and their function and morphology are discussed. Morphological analysis of notal and postnotal organs in extant species permits us to conclude that B. damzeni sp.n. is characterized by the most developed and complex notal organs in all Mecoptera.     

Description of Euroleptochromus gen.n. (Coleoptera,Staphylinidae, Scydmaeninae) from Baltic amber,with discussion of biogeography and mouthpart evolution within Clidicini

A new extinct species of the ant‐like stone beetle supertribe Mastigitae, Euroleptochromus sabathi gen. & sp.n. is described from Eocene Baltic amber. A phylogenetic analysis of Clidicini, with representatives of Leptomastacini and Mastigini as out‐group taxa, provided strong support for a sister‐group relationship between the Neotropical Leptochromus and the new genus. The monophyly of Clidicini is questioned because of an alternative placement of Nearctic Papusus as a sister taxon to Leptomastacini + [Clidicus + (Palaeoleptochromus + (Euroleptochromus + Leptochromus))]. A dispersal‐vicariance analysis provided three alternative scenarios for the evolution of Mastigitae; with Laurasia as the ancestral area of the supertribe, major branching events occurring within either Eurasia or Laurentia and two trans‐Beringia dispersals in Late Cretaceous and Eocene. Euroleptochromus, Palaeoleptochromus and Leptochromus share highly derived structures on postgenae and maxillary palps, probably as part of a specialised feeding or prey capture mechanism. The formation of these modifications in Clidicini is demonstrated to involve a process (traced back to the Campanian, 79 Ma) of elongation and narrowing of maxillary palps and forming a cuticular setal projection from a broadened insertion site of sensory setae.