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991.
Gottfried Fränkel 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1925,2(6):658-690
Ohne Zusammenfassung 相似文献
992.
Gottfried Fraenkel 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1927,6(3-4):385-401
Ohne Zusammenfassung
Elysia viridis findet sich reichlich zusammen mit andern Opisthobranchiern auf grünen Algen in den Häfen St. Lucia und Mergelina in Neapel. 相似文献
993.
Using a sophisticated aerodynamic method, the effects of extremely large dihedral on the aerodynamic characteristics of birds are determined. With this method, it is possible to generate solutions for the addressed aerodynamic problem, which shows a high complexity due to interference effects caused by dihedral and pronounced 3-dimensional flow properties as well as due to complex wing geometries. From the obtained results it follows that extremely large dihedral has substantial effects on the aerodynamic force characteristics. There are significant changes in the lift, the drag and the side force, thus affecting the flight performance. Furthermore, the obtained results show that the aerodynamic rolling and yawing moment characteristics are influenced by extremely large dihedral to a high degree. This is a significant outcome for lateral-directional stability because the aerodynamic rolling and yawing moment characteristics have a determinative influence here. 相似文献
994.
Sandra Viale-Bouroncle Martin Gosau Kevin Küpper Christoph Möhl Gero Brockhoff Torsten E. Reichert Gottfried Schmalz Tobias Ettl Christian Morsczeck 《Differentiation; research in biological diversity》2012
Stem cell fate can be induced by the grade of stiffness of the extracellular matrix, depending on the developed tissue or complex tissues. For example, a rigid extracellular matrix induces the osteogenic differentiation in bone marrow derived mesenchymal stem cells (MSCs), while a softer surface induces the osteogenic differentiation in dental follicle cells (DFCs). To determine whether differentiation of ectomesenchymal dental precursor cells is supported by similar grades of extracellular matrices (ECMs) stiffness, we examined the influence of the surface stiffness on the proliferation and osteogenic differentiation of stem cells from human exfoliated deciduous teeth (SHED). Cell proliferation of SHED was significantly decreased on cell culture surfaces with a muscle-like stiffness. A dexamethasone-based differentiation medium induced the osteogenic differentiation of SHED on substrates of varying mechanical stiffness. Here, the hardest surface improved the induction of osteogenic differentiation in comparison to that with the softest stiffness. In conclusion, our study showed that the osteogenic differentiation of ectomesenchymal dental precursor cells SHED and DFCs are not supported by similar grades of ECM stiffness. 相似文献
995.
Gottfried Fraenkel 《Zoomorphology》1927,7(4):597-608
Ohne Zusammenfassung 相似文献
996.
A trade-off between the parameters of Lotka–Volterra systems is used to give verifications of relations between intrinsic growth rate and limiting capacity and the stability type of the resulting dynamical system. The well known rock–paper–scissors game serves as a template for toxin mediated interactions, which is best represented by the bacteriocin producing Escherichia coli bacteria. There, we have three strains of the same species. The producer produces a toxin lethal to the sensitive, while the resistant is able to protect itself from that toxin. Due to the fact that there are costs for production and for resistance, a dynamics similar to the rock–paper–scissors game results. By using an adaptive dynamics approach for competitive Lotka–Volterra systems and assuming an inverse relation (trade-off) between intrinsic growth rate (IGR) and limiting capacity (LC) we obtain evolutionary and convergence stable relations between the IGR’s and the LC’s. Furthermore this evolutionary process leads to a phase topology of the population dynamics with a globally stable interior fixed point by leaving the interaction parameters constant. While the inverse trade-off stabilizes coexistence and does not allow branching, toxicity itself can promote diversification. The results are discussed in view of several biological examples indicating that the above results are structurally valid. 相似文献
997.
Vicky M. Oelze Isabella O'Neal Roman M. Wittig Kornelius Kupczik Ellen Schulz-Kornas Gottfried Hohmann 《American journal of primatology》2023,85(1):e23436
Feces are a treasure trove in the study of animal behavior and ecology. Stable carbon and nitrogen isotope analysis allows to assess the dietary niches of elusive primate species and primate breastfeeding behavior. However, some fecal isotope data may unwillingly be biased toward the isotope ratios of undigested plant matter, requiring more consistent sample preparation protocols. We assess the impact of this potential data skew in 114 fecal samples of wild bonobos (Pan paniscus) by measuring the isotope differences (Δ13C, Δ15N) between bulk fecal samples containing larger particles (>1 mm) and filtered samples containing only small particles (<1 mm). We assess the influence of fecal carbon and nitrogen content (ΔC:N) and sample donor age (subadult, adult) on the resulting Δ13C, Δ15N values (n = 228). Additionally, we measure the isotope ratios in three systematically sieved fecal samples of chimpanzees (Pan troglodytes verus), with particle sizes ranging from 20 μm to 8 mm (n = 30). We found differences in fecal carbon and nitrogen content, with the smaller fecal fraction containing more nitrogen on average. While the Δ13C values were small and not affected by age or ΔC:N, the Δ15N values were significantly influenced by fecal ΔC:N, possibly resulting from the differing proportions of undigested plant macroparticles. Significant relationships between carbon stable isotope ratios (δ13C) values and %C in large fecal fractions of both age groups corroborated this assessment. Δ15N values were significantly larger in adults than subadults, which should be of concern in isotope studies comparing adult females with infants to assess breastfeeding. We found a random variation of up to 3.0‰ in δ13C and 2.0‰ in nitrogen stable isotope ratios within the chimpanzee fecal samples separated by particle sizes. We show that particle size influences isotope ratios and propose a simple, cost-effective filtration method for primate feces to exclude larger undigested food particles from the analysis, which can easily be adopted by labs worldwide. 相似文献
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