Influence of soil and climate heterogeneity on the performance of economic instruments for reducing nitrate leaching from agriculture

Economic instruments can be used to control groundwater nitrate pollution due to the intensive use of fertilizers in agriculture. In order to test their efficiency on the reduction of nitrate leaching, we propose an approach based on the combined use of production and pollution functions to derive the impacts on the expected farmer response of these instruments. Some of the most important factors influencing nitrate leaching and crop yield are the type of soil and the climatic conditions. Crop yield and nitrate leaching responses to different soil and climaticconditions were classified by means of a cluster analysis, and crops located in different areas but with similar response were grouped for the analysis. We use a spatial economic optimization model to evaluate the potential of taxes on nitrogen fertilizers, water prices, and taxes on nitrate emissions to reduce nitrate pollution, as well as their economic impact in terms of social welfare and farmers' net benefits. Themethod was applied to theMancha Oriental System(MOS) in Spain, a large area with different soil types and climatic conditions.We divided the study area into zones of homogeneous crop production and nitrate leaching properties. Results how spatially different responses of crop growth and nitrate leaching, proving howthe cost-effectiveness of pollution control instruments is contingent upon the spatial heterogeneities of the problem.The study has been supported by the European Community 7th Framework Project GENESIS (226536) on groundwater.Peña Haro, S.; García Prats, A.; Pulido-Velazquez, M. (2014). Influence of soil and climate heterogeneity on the performance of economic instruments for reducing nitrate leaching from agriculture. Science of the Total Environment. 499:510-519. https://doi.org/10.1016/j.scitotenv.2014.07.029S51051949

Concentration-Dependent, Size-Independent Toxicity of Citrate Capped AuNPs in Drosophila melanogaster

The expected potential benefits promised by nanotechnology in various fields have led to a rapid increase of the presence of engineered nanomaterials in a high number of commercial goods. This is generating increasing questions about possible risks for human health and environment, due to the lack of an in-depth assessment of the physical/chemical factors responsible for their toxic effects. In this work, we evaluated the toxicity of monodisperse citrate-capped gold nanoparticles (AuNPs) of different sizes (5, 15, 40, and 80 nm) in the model organism Drosophila melanogaster, upon ingestion. To properly evaluate and distinguish the possible dose- and/or size-dependent toxicity of the AuNPs, we performed a thorough assessment of their biological effects, using two different dose-metrics. In the first approach, we kept constant the total surface area of the differently sized AuNPs (Total Exposed Surface area approach, TES), while, in the second approach, we used the same number concentration of the four different sizes of AuNPs (Total Number of Nanoparticles approach, TNN). We observed a significant AuNPs-induced toxicity in vivo, namely a strong reduction of Drosophila lifespan and fertility performance, presence of DNA fragmentation, as well as a significant modification in the expression levels of genes involved in stress responses, DNA damage recognition and apoptosis pathway. Interestingly, we found that, within the investigated experimental conditions, the toxic effects in the exposed organisms were directly related to the concentration of the AuNPs administered, irrespective of their size

Screening for anti-inflammatory <i>T. wortmannii</i> components.

<p>(A) Flow cytometric analysis of ICAM-1 expression on the cell surface of HUVECs. Cells were stimulated with 10 ng/ml hTNF-α with or without 25 µg/ml crude extract or left untreated as negative control and stained with mouse anti-human ICAM-1 mAB. (B) Screening for anti-inflammatory substances, using a cell-based ELISA. Cells were treated for 1h in the absence or presence of 25 µg/ml substances AA, BB, C, D and crude extract, prior to being stimulated for 24 h with 10 ng/ml hTNF-α and stained with human ICAM-1 mAB (C) HEK293 cells were transiently transfected with NF-κB-Luciferase construct and EGFP construct. 24 h later, transfected cells were treated with 0, 40, 20 or 10 µg/ml substances or crude extract, prior to being stimulated with 10 ng/ml hTNF-α. Luciferase activities was determined 8 h later, normalized to the EFGP activities and expressed as fold increase over the control. (*, p<0.05; **, p<0.01, Students <i>t</i> test).</p