Increased dispersal rates and distances in density-stressed bush crickets (Metriophera brachyptera).

Der infolge der Habitatfragmentierung eingeschränkte Individuenaustausch zwischen Populationen gilt als einer der Hauptgründe für ein erhöhtes Aussterberisiko insbesondere bei standorttreuen Arten mit geringem Ausbreitungspotential. Einige Untersuchungen an Heuschrecken deuten jedoch an, dass das Ausbreitungsvermögen standorttreuer Arten bisher möglicherweise unterschätzt worden ist. Es wird angenommen, daß bestimmte Umweltbedingungen bei diesen Arten Ausbreitungsverhalten auslösen und ihr Ausbreitungsvermögen erhöhen kann. An der Kurzflügeligen Beißschrecke Metrioptera brachyptera (L., 1761) wurden in einem ersten Schritt die Emigrationsraten bei verschiedenen Populationsdichten in 'Mikrokosmen' (Käfigpopulationen) untersucht. Der Anteil der Individuen, die aus den Käfigen auswanderten, war positiv mit der Individuendichte in den Käfigen korreliert. In einem zweiten Schritt wurden sowohl Indivduen, die unter Dichtestress gehalten wurden, als auch Tiere, die keinen hohen Individuendichten ausgesetzt waren, auf einem Fußballplatz freigelassen und ihr Ausbreitungsmuster untersucht. 'Gestresste' Individuen dispergierten signifikant schneller und weiter als 'ungestresste'. Die Ergebnisse weisen darauf hin, dass Ausbreitungsverhalten induzierbar ist und auch bei standorttreuen Arten auftreten kann. Es ist bei diesen jedoch keine regelmäßige Erscheinung, sondern besitzt Ausnahmecharakter.StichwörterDispersal, emigration, experimental approach, metapopulation, microcosm.The limitation of dispersal due to habitat fragmentation is considered as one key factor for an increasing risk of extinction especially in sedentary species with low dispersal ability. A few studies on grasshoppers and crickets indicate that dispersal ability even of sedentary species may have been underestimated in the past. It is argued that certain environmental conditions can trigger and increase dispersal in such species. In a first set of experiments emigration rates of the bush cricket Metrioptera brachyptera (L., 1761) were recorded in 'microcosms' (cage-populations) with various 'population' densities. The proportion of emigrants was correlated with increasing densities. In a second set of experiments individuals stressed by high densities as well as individuals that were not submitted to this stress were released on a soccer field and dispersal patterns of both groups were recorded. Stressed individuals dispersed significantly faster and further than unstressed ones. The results indicate that dispersal is induced by certain environmental conditions suggesting episodic colonization patterns which occur even in sedentary species.KeywordsDispersal, emigration, experimental approach, metapopulation, microcosm

Change of species set and abundance along a short time gradient: The impact of weather conditions on the conservation of butterflies.

In einer artenarmen Region im Märkischen Sauerland (Nordrhein-Westfalen) wurde 1989-1991 eine rasterfeldbezogene Dauerbeobachtung von Tagfaltern begonnen und 1997 wiederholt. Gegenüber 1989-1991 zeigten sich 1997 Unterschiede im Artenset und der Abundanz einiger Arten. In Übereinstimmung mit anderen Untersuchungen wird diesbezüglich der Einfluß von Witterungsbedingungen diskutiert. In einem Betrachtungszeitraum von 1987 bis 1995 sind die Witterungsbedingungen im Untersuchungsgebiet seit 1989 günstiger geworden. Die mittleren Monatstemperaturen und die monatliche Sonnenscheindauer sind vor allem zwischen 1989 und 1992 deutlich angestiegen, während die monatliche Niederschlagssumme stark abgenommen hat. Dieser Anstieg war sowohl während der hauptsächlichen Falterflugzeit (April bis September) als auch von Oktober bis März (möglicherweise für Präimaginalstadien relevant) festzustellen. - Einige vergleichsweise xerothermophile Arten konnten 1997 erstmals nachgewiesen werden. Andere, während der letzten 30 Jahre verschwundene Arten, wurden wiedergefunden. Mehrere Arten mit individuenarmen Vorkommen während der Erfassungen 1989-1991 besaßen 1997 eine größere Zahl und individuenstärkere Vorkommen, obwohl sich weder die Landschaftsstrukturen noch die Habitatbedingungen im Untersuchungsgebiet wesentlich geändert haben. Witterungsbedingungen werden hierfür als Ursache diskutiert und mit möglichen Auswirkungen von Habitatmanagement verglichen.StichwörterButterfly monitoring, species set, impact of weather conditions, Germany, nature conservation.In a species-poor region of a low-mountain area of Nordrhein-Westfalen (Germany) a butterfly monitoring scheme that was started in 1989-1991 and repeated in 1997 revealed changes in the species set and the frequency (abundance) of several species. In line with previous studies the impact of weather conditions on butterfly occurrence and frequency is discussed. As regards the nine-year period from 1987-1995 weather conditions in the study area have become more favourable since 1989. An increase in the average monthly temperatures and the monthly amount of sunshine and a decrease in monthly rainfall was mainly recorded between 1989 and 1992. The increase was observed during the main flight period (April to September) as well as between October and March (possibly relevant for juvenile stages of several species). Several xerothermophilous species never before recorded in the study area were found to have immigrated. Other species which had vanished during the last thirty years have notably recovered, although landscape structure and habitat conditions have remained basically unchanged. - The importance of favourable weather conditions for the immigration and recovery of rare or endangered species is discussed and compared to the effects of conservation management.KeywordsButterfly monitoring, species set, impact of weather conditions, Germany, nature conservation

Selektive Wacker-Oxidation von 1,9-Cyclohexadecadien zu 8-Cyclohexadecenon und Funktionalisierungsreaktionen anderer duftstoffrelevanter Substrate

In dieser Arbeit wurde die direkte Oxidation des 1,9-CHDD zu 8-CHD durchgeführt. Mittels Wacker-Oxidation ließ sich das Zielprodukt 8-CHD selektiv unter milden Reaktionsbedingungen darstellen. Darüber hinaus gelang es, das anfänglich anaerobe Oxidationssystem unter Gesichtspunkten „Grüner Chemie“ mit Sauerstoff als finalem Oxidans zu koppeln. Mechanistische Untersuchungen zur Klärung der Ursache für die Katalysatordesaktivierung lassen eine Inhibierung des Katalysators durch das reine (E/E)-1,9-CHDD vermuten und stellen ein großes Problem für das zugrundeliegende Reaktionssystem dar.In the present work, direct oxidation of 1,9-CHDD to 8-CHD was performed in a single reaction step. Using a modified Wacker-type oxidation reaction, the target product 8-CHD was selectively synthesized under mild reaction conditions. The initially anaerobic oxidation system was furthermore successfully coupled with oxygen as the final oxidant under the aspects of "green chemistry". Mechanistic investigations revealed that the catalyst was presumably inhibited by one of the diene isomers and presented a major drawback for this Wacker-type oxidation

An automatic critical care urine meter

Nowadays patients admitted to critical care units have most of their physiological parameters measured automatically by sophisticated commercial monitoring devices. More often than not, these devices supervise whether the values of the parameters they measure lie within a pre-established range, and issue warning of deviations from this range by triggering alarms. The automation of measuring and supervising tasks not only discharges the healthcare staff of a considerable workload but also avoids human errors in these repetitive and monotonous tasks. Arguably, the most relevant physiological parameter that is still measured and supervised manually by critical care unit staff is urine output (UO). In this paper we present a patent-pending device that provides continuous and accurate measurements of patient’s UO. The device uses capacitive sensors to take continuous measurements of the height of the column of liquid accumulated in two chambers that make up a plastic container. The first chamber, where the urine inputs, has a small volume. Once it has been filled it overflows into a second bigger chamber. The first chamber provides accurate UO measures of patients whose UO has to be closely supervised, while the second one avoids the need for frequent interventions by the nursing staff to empty the containe

Extending ontologies by finding siblings using set expansion techniques

Motivation: Ontologies are an everyday tool in biomedicine to capture and represent knowledge. However, many ontologies lack a high degree of coverage in their domain and need to improve their overall quality and maturity. Automatically extending sets of existing terms will enable ontology engineers to systematically improve text-based ontologies level by level

Intra-radicular dentin treatments and retention of fiber posts with self-adhesive resin cements

The aim of this study was to evaluate the effect of treating intraradicular dentin with irrigating solutions on the retention of glass-fiber posts luted with self-adhesive resin cement. Bovine incisors were endodontically treated, and 9-mm-deep postholes were prepared. Before inserting the cement, the root canals were irrigated with various solutions: 11.5% polyacrylic acid for 30 s, 17% EDTA for 60 s, or 5% NaOCl for 60 s, respectively. Irrigation with distilled water was used in the control group. After all specimens had been rinsed with distilled water, the excess moisture was removed and the posts were luted using either BisCem (Bisco) or RelyX Unicem clicker (3M ESPE). Seven days after luting, the specimens were sectioned transversally into 1-mm-thick slices, which were submitted to push-out testing on a mechanical testing machine. Bond strength data (n = 6 per group) were analyzed by two-way ANOVA and Student-Newman-Keuls' test (α = 0.05). For Unicem, EDTA showed lower bond strength than the other solutions, which had similar results. For BisCem, EDTA showed higher bond strength than the other treatments, while application of NaOCl yielded higher bond strength than polyacrylic acid whereas the control group had intermediate results. In conclusion, irrigating root canals before insertion of self-adhesive resin cements, especially EDTA, might interfere with retention of the fiber posts