Zur Bedeutung von Regenwasserrückhaltebecken für Libellen (Odonata) – ein Beitrag zum urbanen Artenschutz

Im Laufe der Vegetationsperiode 1997 wurden an fünf ausgewählten Regenwasserrückhaltebecken (RWRB) in Osnabrück (Niedersachsen) Untersuchungen zur Libellenfauna durchgeführt. Ziel der Erhebungen war es, die Bedeutung innerstädtischer RWRB für den Artenschutz zu ermitteln. Auf den fünf Untersuchungsflächen konnten mit insgesamt 22 Libellenarten 81,8% der 27 im Stadtgebiet vorkommenden Odonatenarten erfaßt werden. An den einzelnen RWRB variierten die Zahlen zwischen acht und 19 Arten. Die Dominanz von Habitatgeneralisten ist aufgrund der Art und Lage der Flächen nicht überraschend. Hervorzuheben ist das Vorkommen von Arten, die eine Präferenz für Sekundärlebensräume und/oder thermisch begünstigte Flächen aufweisen. Die Ergebnisse zeigen, daß innerstädtische RWRB eine wichtige Rolle im Artenschutz spielen können. Wesentliche Voraussetzungen sind eine hohe, vor allem vegetationsbedingte Strukturvielfalt, eine günstige räumliche Einbindung, die Minimierung von Gefährdungen und Beeinträchtigungen und eine an ökologischen Kriterien ausgerichtete Anlage, Pflege und Entwicklung der Becken.In the course of the vegetation period of 1997, investigations on dragonfly fauna were carried out at five selected rainwater retention basins (RWRB) in Osnabrück (Lower Saxony). The objective of the data collectionwas to assess the significance of inner-city RWRBs for the preservation of species. Altogether, 22 of the 27 different Odonata species that occur in Osnabrück were recorded at the five areas of investigation. The numbers occurring varied from eight to 19 species at the individual RWRBs. The dominance of habitat generalists is not surprising, due to the type and location of the areas. The occurrence of species that show a preference for secondary habitats and/or thermally-advantaged areas should be emphasised. The results demonstrate that inner-city RWRBs can play an important role in the preservation of species. The main requirements are a wide variety of structure, in particular with regard to vegetation, favourable spatial integration, the minimisation of endangerment and disturbances, and basins that are structured, maintained and developed according to ecological criteria

Die Bewertung der Degradation deutscher Fließgewässer mit dem Makrozoobenthos. Ein multimetrischer gewässertypspezifischer Ansatz.

Hintergrund der Dissertation ist die EG-Wasserrahmenrichtlinie (EG-WRRL) der Europäischen Union (2000). Die EG-WRRL sieht, im Unterschied zur bisherigen Bewertungspraxis in Deutschland, eine integrierte biologische Bewertung des ökologischen Zustands von Fließgewässern vor. Die Bewertung erfolgt über biologische Indikatoren wie benthische Wirbellose (Mkrozoobenthos), Fische und die aquatische Flora. Für die Umsetzung der EG-WRRL sind somit gänzlich neue Bewertungsverfahren erforderlich. Inhaltlicher Schwerpunkt und Ziel der Dissertation ist die Entwicklung eines zentralen Moduls als Bestandteil eines modular aufgebauten, gewässertypspezifischen Bewertungsverfahrens für alle deutschen Fließgewässertypen auf Grundlage des Makrozoobenthos. Es wird als Modul „Allgemeine Degradation“ bezeichnet, da es die Auswirkungen verschiedener Stressoren (u. a. Degradation der Gewässermorphologie, Nutzung im Einzugsgebiet, Stauhaltung, Restwasserführung) integrativ wiedergeben soll. Das Modul basiert auf einem multimetrischen Ansatz. Durch die Verrechnung der Ergebnisse verschiedener Einzelindizes erhält man ein vollständigeres Bild des ökologischen Zustands eines Gewässerabschnitts. Weitere Vorteile liegen in der hohen Stabilität des Bewertungsergebnisses und der Möglichkeit, das Modul an die Gegebenheiten der verschiedenen Gewässertypen anzupassen. Die Grundlage für die Entwicklung des Moduls „Allgemeine Degradation“ stellen rund 3.000 Makrozoobenthos-Datensätze sowie die hierzu ermittelten abiotischen Begleitdaten – Daten zur Gewässerstrukturgüte und zur Bodennutzung im Einzugsgebiet – dar. Da sich das Modul „Allgemeine Degradation“ zur Anwendung in der Praxis eignen soll schließt sich nach Abschluss der Entwicklung des Moduls eine intensive Testphase an. Die Ergebnisse dieses Praxistests bilden die Grundlage für eine abschließende Überarbeitung des Moduls

Vortex circulation patterns in planar microdisk arrays

We report a magnetic X-ray microscopy study of the pattern formation of circulation in arrays of magnetic vortices ordered in a hexagonal and a honeycomb lattice. In the honeycomb lattice, we observe at remanence an ordered phase of alternating circulations, whereas in the hexagonal lattice, small regions of alternating lines form. A variation in the edge-to-edge distance shows that the size of those regions scales with the magnetostatic interaction. Micromagnetic simulations reveal that the patterns result from the formation of flux closure states during the nucleation process

Daily Caffeine Intake Induces Concentration-Dependent Medial Temporal Plasticity in Humans: A Multimodal Double-Blind Randomized Controlled Trial

Caffeine is commonly used to combat high sleep pressure on a daily basis. However, interference with sleep-wake regulation could disturb neural homeostasis and insufficient sleep could lead to alterations in human gray matter. Hence, in this double-blind, randomized, cross-over study, we examined the impact of 10-day caffeine (3 × 150 mg/day) on human gray matter volumes (GMVs) and cerebral blood flow (CBF) by fMRI MP-RAGE and arterial spin-labeling sequences in 20 habitual caffeine consumers, compared with 10-day placebo (3 × 150 mg/day). Sleep pressure was quantified by electroencephalographic slow-wave activity (SWA) in the previous nighttime sleep. Nonparametric voxel-based analyses revealed a significant reduction in GMV in the medial temporal lobe (mTL) after 10 days of caffeine intake compared with 10 days of placebo, voxel-wisely adjusted for CBF considering the decreased perfusion after caffeine intake compared with placebo. Larger GMV reductions were associated with higher individual concentrations of caffeine and paraxanthine. Sleep SWA was, however, neither different between conditions nor associated with caffeine-induced GMV reductions. Therefore, the data do not suggest a link between sleep depth during daily caffeine intake and changes in brain morphology. In conclusion, daily caffeine intake might induce neural plasticity in the mTL depending on individual metabolic processes

Daily Caffeine Intake Induces Concentration-Dependent Medial Temporal Plasticity in Humans: A Multimodal Double-Blind Randomized Controlled Trial

Caffeine is commonly used to combat high sleep pressure on a daily basis. However, interference with sleep–wake regulation could disturb neural homeostasis and insufficient sleep could lead to alterations in human gray matter. Hence, in this double-blind, randomized, cross-over study, we examined the impact of 10-day caffeine (3 × 150 mg/day) on human gray matter volumes (GMVs) and cerebral blood flow (CBF) by fMRI MP-RAGE and arterial spin-labeling sequences in 20 habitual caffeine consumers, compared with 10-day placebo (3 × 150 mg/day). Sleep pressure was quantified by electroencephalographic slow-wave activity (SWA) in the previous nighttime sleep. Nonparametric voxel-based analyses revealed a significant reduction in GMV in the medial temporal lobe (mTL) after 10 days of caffeine intake compared with 10 days of placebo, voxel-wisely adjusted for CBF considering the decreased perfusion after caffeine intake compared with placebo. Larger GMV reductions were associated with higher individual concentrations of caffeine and paraxanthine. Sleep SWA was, however, neither different between conditions nor associated with caffeine-induced GMV reductions. Therefore, the data do not suggest a link between sleep depth during daily caffeine intake and changes in brain morphology. In conclusion, daily caffeine intake might induce neural plasticity in the mTL depending on individual metabolic processes

Contact-controlled amoeboid motility induces dynamic cell trapping in 3D-microstructured surfaces.

On flat substrates, several cell types exhibit amoeboid migration, which is characterized by restless stochastic successions of pseudopod protrusions. The orientation and frequency of new membrane protrusions characterize efficient search modes, which can respond to external chemical stimuli as observed during chemotaxis in amoebae. To quantify the influence of mechanical stimuli induced by surface topography on the migration modes of the amoeboid model organism Dictyostelium discoideum, we apply high resolution motion analysis in microfabricated pillar arrays of defined density and geometry. Cell motion is analyzed by a two-state motility-model, distinguishing directed cellular runs from phases of isotropic migration that are characterized by randomly oriented cellular protrusions. Cells lacking myosin II or cells deprived of microtubules show significantly different behavior concerning migration velocities and migrational angle distribution, without pronounced attraction to pillars. We conclude that microtubules enhance cellular ability to react with external 3D structures. Our experiments on wild-type cells show that the switching from randomly formed pseudopods to a stabilized leading pseudopod is triggered by contact with surface structures. These alternating processes guide cells according to the available surface in their 3D environment, which we observed dynamically and in steady-state situations. As a consequence, cells perform "home-runs" in low-density pillar arrays, crawling from pillar to pillar, with a characteristic dwell time of 75 s. At the boundary between a flat surface and a 3D structured substrate, cells preferentially localize in contact with micropillars, due to the additionally available surface in the microstructured arrays. Such responses of cell motility to microstructures might open new possibilities for cell sorting in surface structured arrays

The dilemma of neuroprotection trials in times of successful endovascular recanalization.

BACKGROUND The "translational roadblock" between successful animal stroke studies and neutral clinical trials is usually attributed to conceptual weaknesses. However, we hypothesized that rodent studies cannot inform the human disease due to intrinsic pathophysiological differences between rodents and humans., i.e., differences in infarct evolution. METHODS To verify our hypothesis, we employed a mixed study design and compared findings from meta-analyses of animal studies and a retrospective clinical cohort study. For animal data, we systematically searched pubmed to identify all rodent studies, in which stroke was induced by MCAO and at least two sequential MRI scans were performed for infarct volume assessment within the first two days. For clinical data, we included 107 consecutive stroke patients with large artery occlusion, who received MRI scans upon admission and one or two days later. RESULTS Our preclinical meta-analyses included 50 studies with 676 animals. Untreated animals had a median post-reperfusion infarct volume growth of 74%. Neuroprotective treatments reduced this infarct volume growth to 23%. A retrospective clinical cohort study showed that stroke patients had a median infarct volume growth of only 2% after successful recanalization. Stroke patients with unsuccessful recanalization, by contrast, experienced a meaningful median infarct growth of 148%. CONCLUSION Our study shows that rodents have a significant post-reperfusion infarct growth, and that this post-reperfusion infarct growth is the target of neuroprotective treatments. Stroke patients with successful recanalization do not have such infarct growth and thus have no target for neuroprotection

How managers can build trust in strategic alliances: a meta-analysis on the central trust-building mechanisms

Trust is an important driver of superior alliance performance. Alliance managers are influential in this regard because trust requires active involvement, commitment and the dedicated support of the key actors involved in the strategic alliance. Despite the importance of trust for explaining alliance performance, little effort has been made to systematically investigate the mechanisms that managers can use to purposefully create trust in strategic alliances. We use Parkhe’s (1998b) theoretical framework to derive nine hypotheses that distinguish between process-based, characteristic-based and institutional-based trust-building mechanisms. Our meta-analysis of 64 empirical studies shows that trust is strongly related to alliance performance. Process-based mechanisms are more important for building trust than characteristic- and institutional-based mechanisms. The effects of prior ties and asset specificity are not as strong as expected and the impact of safeguards on trust is not well understood. Overall, theoretical trust research has outpaced empirical research by far and promising opportunities for future empirical research exist

Consumer perceptions of co-branding alliances: Organizational dissimilarity signals and brand fit

This study explores how consumers evaluate co-branding alliances between dissimilar partner firms. Customers are well aware that different firms are behind a co-branded product and observe the partner firms’ characteristics. Drawing on signaling theory, we assert that consumers use organizational characteristics as signals in their assessment of brand fit and for their purchasing decisions. Some organizational signals are beyond the control of the co-branding partners or at least they cannot alter them on short notice. We use a quasi-experimental design and test how co-branding partner dissimilarity affects brand fit perception. The results show that co-branding partner dissimilarity in terms of firm size, industry scope, and country-of-origin image negatively affects brand fit perception. Firm age dissimilarity does not exert significant influence. Because brand fit generally fosters a benevolent consumer attitude towards a co-branding alliance, the findings suggest that high partner dissimilarity may reduce overall co-branding alliance performance

Individualized versus standardized risk assessment in patients at high risk for adverse drug reactions (IDrug) – study protocol for a pragmatic randomized controlled trial

Background Elderly patients are particularly vulnerable to adverse drug reactions, especially if they are affected by additional risk factors such as multimorbidity, polypharmacy, impaired renal function and intake of drugs with high risk potential. Apart from these clinical parameters, drug safety and efficacy can be influenced by pharmacogenetic factors. Evidence-based recommendations concerning drug-gene-combinations have been issued by international consortia and in drug labels. However, clinical benefit of providing information on individual patient factors in a comprehensive risk assessment aiming to reduce the occurrence and severity of adverse drug reactions is not evident. Purpose of this randomized controlled trial is to compare the effect of a concise individual risk information leaflet with standard information on risk factors for side effects. Methods/Design The trial was designed as a prospective, two-arm, randomized, controlled, multicenter, pragmatic study. 960 elderly, multimorbid outpatients in general medicine are included if they take at least one high risk and one other long-term drug (polymedication). As high risk “index drugs” oral anticoagulants and antiplatelets were chosen because of their specific, objectively assessable side effects. Following randomization, test group patients receive an individualized risk assessment leaflet evaluating their personal data concerning bleeding- and thromboembolic-risk-scores, potential drug-drug-interactions, age, renal function and pharmacogenetic factors. Control group patients obtain a standardized leaflet only containing general information on these criteria. Follow-up period is 9 months for each patient. Primary endpoint is the occurrence of a thromboembolic/bleeding event or death. Secondary endpoints are other adverse drug reactions, hospital admissions, specialist referrals and medication changes due to adverse drug reactions, the patients’ adherence to medication regimen as well as health related quality of life, mortality and resulting costs. Discussion Despite extensive evidence of risk factors for adverse drug reactions, there are few prospective trial data about an individualized risk assessment including pharmacogenetic information to increase patient safety. By conducting a health economic analysis, we will evaluate if the application of an individualized drug therapy in daily routine is cost-effective. Trial registration German Clinical Trials Register: DRKS00006256, date of registration 09/01/15