Video recordings of prey capture behaviour and associated electric organ discharge of Torpedo marmorata (Chondrichthyes)

The results of an analysis of 16 laboratory records of Torpedo marmorata Risso attacks are presented: when a fish swims near a T. marmorata at rest, the latter jumps and simultaneously immobilizes the prey by its electric organ discharge (EOD). A water stream is used to direct the paralysed prey beneath its disc before swallowing. The attack is made if the prey swims at short distance ( 4 cm); height and direction of the jump are related to the position of the prey. The EOD, interrupted during the jump, reappears when the prey moves under the disc of T. marmorata, and ceases before swallowing. The strength of the EOD is sufficient to break the vertebral column of the prey. The possible receptor organs involved in this behaviour are presumed to be lateral line organs and touch detectors: the former to localize the prey before the jump, the latter to detect it under the disc. Evolutionary convergence of the prey capture behaviour of Torpedo, Malapterurus, and Electrophorus is also discussed.Supported by Research Grant No. 659440 from the Direction de Recherches et Moyens d'Essais (D.R.M.E.) to Dr. T. Szabo.Dr. Bauer's stay in France was sponsored by a N.A.T.O. and a D.F.G. research fellowship.     

Hazard assessment of chemicals in soil

Based on a stepwise (tiered) approach, degradation, adsorption and leaching tests as well as various effect tests (using plants, microorganisms and animals) are recommended for the testing of environmental chemicals. If, after the tests of tiers 1 and 2, the results of a monospecies-effect-test (including a safety factor) are within the range of the predicted exposure, the ecotoxicological hazard should be determined using a terrestrial model ecosystem. Some of the tests for the proposed strategy were selected from practical experience in testing environmental chemicals in the laboratory, and some on the basis of a comprehensive literature review.     

Photocatalytic oxidation of gaseous chlorinated organics over titanium dioxide

The photocatalytic oxidation of high levels of volatile chlorinated organic compounds in gas phase has been studied using a specially designed photoreactor. The influence of light intensity, initial water vapour concentration, temperature, inlet contaminant concentration and flow rate on destruction efficiency has been investigated. The performance of the titanium catalyst was strongly affected by the presence of water in the air stream. Experiments have been most successfully conducted at room temperature, low initial contaminant concentrations, low flow rates and high light intensities. Several by-products have been detected performing photocatalytic degradation of trichloroethylene (TCE) and tetrachloroethylene (PCE). No catalyst deactivation was observed.     

Preparation of high resolution chromosomes from amniotic fluid cells

A relatively simple method of obtaining high resolution chromosomes from amniotic fluid cells is described. The elongated chromosomes are achieved by adding ethidium bromide (5μg/ml) to the culture 4 1/2 hours before harvesting and the high resolution banding can be produced by usual banding procedures.     

Diverse migration strategies in hoopoes (<Emphasis Type="Italic">Upupa epops</Emphasis>) lead to weak spatial but strong temporal connectivity

The annual cycle of migrating birds is shaped by their seasonal movements between breeding and non-breeding sites. Studying how migratory populations are linked throughout the annual cycle—migratory connectivity, is crucial to understanding the population dynamics of migrating bird species. This requires the consideration not only of spatial scales as has been the main focus to date but also of temporal scales: only when both aspects are taken into account, the degree of migratory connectivity can be properly defined. We investigated the migration behaviour of hoopoes (Upupa epops) from four breeding populations across Europe and characterised migration routes to and from the breeding grounds, location of non-breeding sites and the timing of key migration events. Migration behaviour was found to vary both within and amongst populations, and even though the spatial migratory connectivity amongst the populations was weak, temporal connectivity was strong with differences in timing amongst populations, but consistent timing within populations. The combination of diverse migration routes within populations and co-occurrence on the non-breeding grounds between populations might promote exchange between breeding populations. As a result, it might make hoopoes and other migrating bird species with similar strategies more resilient to future habitat or climatic changes and stabilise population trends.