37,698 research outputs found
Adhesive for polyester films cures at room temperature, has high initial tack
Quick room-temperature-cure adhesive bonds polyester-insulated flat electrical cables to metal surfaces and various other substrates. The bond strength of the adhesive may be considerably increased by first applying a commercially available polyamide primer to the polyester film
On the trophic fate of Phaeocystis pouchetii: VII. Sterols and fatty acids reveal sedimentation of Phaocystis-derived organic matter via krill fecal strings
As part of a joint project on the fate of phytoplankton in Balsfjorden in Northern Norway, we investigated the trophic fate and sedimentation potential of Phaeocystis pouchetii by tracing the transition of biomarker patterns from a phytoplankton bloom to sediment traps and during a gut passage experiment. The phytoplankton biomass during the spring bloom 1996 was dominated by colonial P. pouchetii (ca. 85 %) and four members of the diatom family Thalassiosiraceae (ca. 10%). Particulate organic carbon in sediment traps largely consisted of fecal material from the Arctic krill Thysanoessa sp.. Sterol and fatty acid biomarker patterns in the phytoplankton bloom could be reproduced by combining the individual biomarker patterns of the isolated phytoplankters P. pouchetii and Thalassiosira decipiens in a ratio of ca. 75:25. In a laboratory experiment, Arctic krill (Thysanoessa raschii) fed with similar efficiency on Phaeocystis colonies and the Thalassiosiraceae. During gut passage, the abundance of Thalassiosiraceae biomarkers in fecal strings increased relative to Phaeocystis biomarkers, while biomarkers from krill became dominant. This transition of biomarker patterns due to gut passage in T. raschii closely resembled the biomarker transition from the surface bloom to material in sediment traps at 40-170 m depth, which was mainly composed of krill fecal strings. We conclude that krill grazed efficiently on Phaeocystis colonies in Balsfjorden, and caused sedimentation of Phaeocystis-derived organic matter below the euphotic zone via fecal strings. Hence, both transfer to higher trophic levels and sedimentation of Phaeocystis-derived organic matter can be more effective than commonly believed
Dynamics of electron currents in nanojunctions with time-varying components and interactions
We study the dynamics of the electron current in nanodevices where there are
time-varying components and interactions. These devices are a nanojunction
attached to heat baths and with dynamical electron-phonon interactions and a
nanojunction with photon beams incident and reflected at the channel. We use
the two-time nonequilibrium Green's functions technique to calculate the
time-dependent electron current flowing across the devices. We find that
whenever a sudden change occurs in the device, the current takes time to react
to the abrupt change, overshoots, oscillates, and eventually settles down to a
steady value. With dynamical electron-phonon interactions, the interaction
gives rise to a net resistance that reduces the flow of current across the
device when a source-drain bias potential is attached. In the presence of
dynamical electron-photon interactions, the photons drive the electrons to
flow. The direction of flow, however, depends on the frequencies of the
incident photons. Furthermore, the direction of electron flow in one lead is
exactly opposite to the direction of flow in the other lead thereby resulting
in no net change in current flowing across the device.Comment: 7 page
Opposite kinetics of L-leucine and L-phenylalanine induced insulin release studies with the perfused rat pancreas
Analysing the relationship between ectomycorrhizal infection and forest decline using marginal models
This statistical survey originates from the problem of discovering which relationship exists between root ectomycorrhizal infection and health status of forest plants. The sampling scheme takes observations from roots that come from sectors around the tree resulting in a hierarchical association structure of the observations. Marginal regression models are used to analyze the mean effect of the ectomycorrhizal state on a response variable proxy for the health degree of the plants
- …