934 research outputs found
Capturing water repellency cessation time by means of characteristic time method
Funding Information: We thank the Alexander von Humboldt Foundation for financial support of this project and donating post-doctoral fellowship to the first author. We thank Susanne K. Woche, Hanna Böhme, and Martin Volkmann for their assistance with soil sampling, sample preparation, and laboratory analysis. The authors greatly appreciate Prof. Mark Coyne, University of Kentucky, USA for proofreading the draft of the article.Peer reviewedPublisher PD
A combined flow cell–respiration box to quantify carbon transformation processes in undisturbed soil
A new experimental laboratory design is introduced to analyze and quantify transport and turnover processes in top- and subsoils. The proposed technique allows the monitoring of transformation processes in an undisturbed soil matrix while preserving entirely intact soil particle interfaces. The experimental setup with undisturbed soil samples, which are embedded into two coupled gas sealed chambers, allows on-time measurement of soil respiration processes under realistic moisture, water flux, and temperature conditions
Effects of BPA in snails : Oehlmann et al. respond
We welcome critical appraisals that help to provide balance; however, Dietrich et al. gave an unjustified reproach. We feel that Dietrich’s position is severely compromised because he serves as an expert for the bisphenol A (BPA) Industry Group (Brussels, Belgium). We would like to respond to the issues raised by Dietrich et al., as well as to their oversights and inappropriate interpretations of our findings..
Bisphenol A induces superfeminization in the Ramshorn snail Marisa cornuarietis (Gastropoda: Prosobranchia) at environmentally relevant concentrations
Previous investigations have shown that bisphenol A (BPA) induces a superfeminization syndrome in the freshwater snail Marisa cornuarietis at concentrations as low as 1 μg/L. Superfemales are characterized by the formation of additional female organs, enlarged accessory sex glands, gross malformations of the pallial oviduct, and a stimulation of egg and clutch production, resulting in increased female mortality. However, these studies were challenged on the basis of incomplete experimentation. Therefore, the objective of the current approach was to bridge several gaps in knowledge by conducting additional experiments. In an initial series of experiments, study results from the reproductive phase of the snails were evaluated in the sub-micrograms per liter range. Before and after the spawning season, superfemale responses were observed [NOEC (no observed effect concentration) 7.9 ng/L, EC10 (effective concentration at 10%) 13.9 ng/L], which were absent during the spawning season. A further experiment investigated the temperature dependence of BPA responses by exposing snails at two temperatures in parallel. The adverse effect of BPA was at least partially masked at 27°C (EC10 998 ng/L) when compared with 20°C (EC10 14.8 ng/L). In M. cornuarietis, BPA acts as an estrogen receptor (ER) agonist, because effects were completely antagonized by a co-exposure to tamoxifen and Faslodex. Antiandrogenic effects of BPA, such as a significant decrease in penis length at 20°C, were also observed. Competitive receptor displacement experiments indicate the presence of androgen- and estrogen-specific binding sites. The affinity for BPA of the estrogen binding sites in M. cornuarietis is higher than that of the ER in aquatic vertebrates. The results emphasize that prosobranchs are affected by BPA at lower concentrations than are other wildlife groups, and the findings also highlight the importance of exposure conditions
Hydraulic processes and properties of partly hydrophobic soils – capillary rise under transient wetting conditions
Hydraulic processes and properties of partially hydrophobic soils: The effect of water repellency on the characteristic curves estimated from dynamic flow experiments
Soil research done over the past decades, has proven that water repellent soils are widespread in all climates. In order to assess the effect of hydrophobicity in the estimated characteristic curves, inflow/outflow experiments were conducted in the laboratory for one soil and two artificial created hydrophobic mixtures. In the inflow/outflow experiments the pressure head at the bottom of the soil column was increased/decreased and the estimated curves were obtained by means of inverse modeling. Multistep inflow/outflow experiments were also conducted using ethanol instead of water in order to estimate the effect of liquid wetting properties on the estimated characteristic curves of the materials under study. The results have shown that the water retention functions and the unsaturated hydraulic conductivity functions estimated from the dynamic experiments are strongly dependent on the degree of hydrophobicity and the wetting/drying process
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