Coherence properties of infrared thermal emission from heated metallic nanowires

Coherence properties of the infrared thermal radiation from individual heated nanowires are investigated as function of nanowire dimensions. Interfering the thermally induced radiation from a heated nanowire with its image in a nearby moveable mirror, well-defined fringes are observed. From the fringe visibility, the coherence length of the thermal emission radiation from the narrowest nanowires was estimated to be at least 20 um which is much larger than expected from a classical blackbody radiator. A significant increase in coherence and emission efficiency is observed for smaller nanowires.Comment: 4 pages,figures include

Plant density can increase invertebrate postdispersal seed predation in an experimental grassland community

Janzen–Connell effects are negative effects on the survival of a plant’s progeny at high conspecific densities or close to its conspecifics. Although the role of Janzen–Connell effects on the maintenance of plant diversity was frequently studied, only few studies targeted Janzen–Connell effects via postdispersal seed predation in temperate grassland systems. We examined effects of conspecific density (abundance of conspecific adult plants) on postdispersal seed predation by invertebrates of three grassland species (Centaurea jacea, Geranium pratense, and Knautia arvensis) in experimental plant communities. Additionally, we examined the impact of plant species richness and different seed predator communities on total and relative seed predation (= seed predation of one plant species relative to others). We offered seeds in an exclusion experiment, where treatments allowed access for (1) arthropods and slugs, (2) arthropods only, (3) small arthropods only, and (4) slugs only. Treatments were placed in plots covering a gradient of abundance of conspecific adults at different levels of plant species richness (1, 2, 3, 4, 8 species). Two of the plant species (C. jacea and K. arvensis) experienced higher rates of seed predation and relative predation with increasing abundance of conspecific adults. For C. jacea, this effect was mitigated with increasing plant species richness. Differences in seed predator communities shifted seed predation between the plant species and changed the magnitude of seed predation of one plant species relative to the others. We exemplify density-dependent increase in seed predation via invertebrates in grassland communities shaping both the total magnitude of species-specific seed predation and seed predation of one species relative to others. Further differences in seed predator groups shift the magnitude of seed predation between different plant species. This highlights the importance of invertebrate seed predation to structure grasslands via density-dependent effects and differing preferences of consumer groups

Generierung parametrischer Geometriemodelle aus Scanndaten am Beispiel der menschlichen Orbita unter Einbeziehung anthropometrischer Betrachtungen

Geometriemodelle topologisch komplexer Strukturen sind die Basis vieler heutzutage durchgeführten Simulationen wie Finite Element Analysis oder Computational Fluid Dynamics. Ziel dieser Arbeit ist es, ein topologisch korrektes generisches Modell (Urmodell) von hoher Qualität zu erzeugen und dies mit einer Parametrik zu verknüpfen, um spezielle individuelle Geometriemodelle abzuleiten. Die Methoden sollten neben einer guten Anpassung der Geometrie auch eine einfache und intuitive Bedienung ermöglichen. Eine Vorhersagbarkeit des Verhaltens ist hierfür eine Grundvoraussetzung

Langzeitergebnisse der Karotisendarteriektomie und des Stentings bei bilateralen Karotisstenosen:ein intraindividueller Vergleich

Frage: Es soll untersucht werden, ob die Karotisendarteriektomie (CEA) oder das Stenting (CAS) beim selben Patienten bessere Ergebnisse erzielt. Methoden: Die Daten von 75 Patienten mit bilateralen ACI-Stenosen, welche auf der einen Seite mit CEA und auf der anderen Seite mit CAS behandelt wurden, wurden retrospektiv analysiert und das Outcome über 7 Jahre untersucht. Ergebnisse: Auf der CEA-Seite wurde bei 3 Patienten (4%) ein Schlaganfall verzeichnet, auf der CAS-Seite bei einem Patienten (1,3%). Eine Restenose trat nach CEA bei 6 (8%) und nach CAS bei 5 Patienten (6,7%) auf. Nach CEA entstand zudem bei einem Patienten (1,3%) eine Rekurrensparese. Myokardinfarkte und Todesfälle wurden nicht registriert. Die Unterschiede sind statistisch nicht signifikant. Fazit: Beide Verfahren zeigen während des 7-jährigen follow-ups niedrige Komplikationsraten. Es kann keine Aussage darüber getroffen werden, welches Verfahren bei ACI-Stenose-Patienten zu favorisieren ist

Microgeographic adaptation and the effect of pollen flow on the adaptive potential of a temperate tree species

Recent interest for microgeographic adaptation, i.e. adaptation at spatial scales compatible with substantial amount of gene dispersal, offers to reconsider the scale at which evolution occurs (Richardson et al. 2014). Whether gene flow is constraining or facilitating local adaptation at this fine spatial scale remains an unresolved question. Too important gene flow would overwhelm the effects of natural selection and decrease local adaptation along environmental gradients. Conversely, gene flow, and particularly long-distance dispersal events, could play a major role in resupplying the genetic variation of populations and favouring the spread of beneficial alleles (Kremer et al. 2012). Hence, the high dispersal capacities of trees are often assumed to be the main process maintaining the large levels of genetic variation measured in their natural populations. However, evidences for microgeographic adaptation and the quantitative assessment of the impact of gene flow on adaptive genetic variation are still limited in most temperate trees. Here, we sampled 60 open-pollinated families of European beech (Fagus sylvatica L.) from three natural plots, spreading along a short elevation gradient (∼1.5 km) at the warm margin of this species distribution. We analysed the phenotypic and genotypic data of ∼2,300 seedlings grown in a common garden. We focused on 11 potentially adaptive traits with significant heritabilities (Gauzere et al. 2016) and tested for signature of local selection on quantitative trait differentiation. We then identified the offspring likely originating from local or distant pollen immigration events and quantified the role of gene flow in increasing locally the additive variance of traits under selection. We found a significant signal of adaptive differentiation among plots separated by less than one kilometre, with local selection acting on growth and phenological traits. We found that trees in the plots at high elevation, experiencing the lowest temperature conditions, flushed earlier and had a higher height and diameter growth in our common garden than trees from the plot at low elevation. Beech populations originating from higher longitude or elevation have also been shown to be genetically earlier in provenance tests, suggesting that these populations evolved phenological traits promoting a longer vegetation period. At this southern margin of the species, the reduced allocation to stem growth at the low elevation plot is likely an adaptive response to drought, which has previously been described by comparing marginal vs central beech populations. Consistently with theoretical expectations, our results suggest a beneficial effect of pollen dispersal by increasing the genetic diversity for these locally differentiated traits. These effects were quantitatively high, with more than twice higher genetic variance for immigrant than local offspring, although with large standard errors around estimates. Our results highlight that local selection is an important evolutionary force in natural tree populations, and provide a strong evidence that adaptive genetic differentiation can occur despite high gene flow. For the two genetically differentiated traits, our analyses suggested a beneficial effect of pollen dispersal by increasing genetic diversity after one episode of reproduction. The findings suggest that conservation and management interventions to facilitate movement of gametes along short ecological gradients would boost genetic diversity of individual tree populations, and thereby enhance their adaptive potential

3rd International Conference of Continental Ichnology 2019 Field Trip Guide

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Overview of the Permian and Triassic tetrapod trackway localities in Saxony-Anhalt, Germany

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