Floristic composition and community structure of epiphytic angiosperms in a terra firme forest in central Amazonia

This survey aimed to describe the floristic composition and structure of the epiphytic community occurring in a terra firme forest in the city of Coari, Brazil, in the Amazon region. Data collection was performed with a 1.5 ha plot method, with which upland, slope and lowland habitats were sampled. All angiosperm epiphytes and their host plants (diameter at breast height > 10 cm) were sampled. We recorded 3.528 individuals in 13 families, 48 genera and 164 species. Araceae was the most prevalent family with regard to the importance value and stood out in all related parameters, followed by Bromeliaceae, Cyclanthaceae and Orchidaceae. The species with the highest epiphytic importance values were Guzmania lingulata (L.) Mez. and Philodendron linnaei Kunth. The predominant life form was hemiepiphytic. Estimated floristic diversity was 3.2 (H'). The studied epiphytic community was distributed among 727 host plants belonging to 40 families, 123 genera and 324 species. One individual of Guarea convergens T.D. Penn. was the host with the highest richness and abundance of epiphytes. Stems/trunks of host plants were the most colonized segments, and the most favorable habitat for epiphytism was the lowlands, where 84.1% of species and 48.2% of epiphytic specimens were observed

Direct evidence for projectile charge state dependent crater formation due to fast ions

We report on craters formed by individual 3 MeV u Auqini ions of selected incident charge states qini penetrating thin layers of poly methyl methacrylate . Holes and raised regions are formed around the region of the impact, with sizes that depend strongly and differently on qini. Variation of qini, of the film thickness and of the angle of incidence allows us to extract information about the depth of origin contributing to different crater feature

Rotation of a sphere in a viscoelastic fluid under flow

The rotation speed of spherical particles in a shear flow is studied experimentally in rheologically different fluids. The fluids, selected to highlight specific constitutive features, include a Newtonian fiuid, a Boger fluid, a wormhke micellar surfactant solution, and a shear thinning elastic polymer solution. It is shown experimentally that particle rotation slows down, when compared to the Newtonian case, as elasticity increases. This is in qualitative agreement with TFEM simulation studies. Furthermore, the dimensionless rotation speed of the spheres in the different fluids as function of the elasticity of the medium scales onto a single curve. This scaling with the Weissenberg number was somewhat unexpected given simulation results for different rheological models, where significant differences are observed for selected single relaxation time differential models