Must Organic certification fundamentally change for an Organic World?

Organic guarantee systems have evolved drastically in the past, accompanying changes in the uptake of Organic agriculture. From an originally fully stakeholder-driven and participatory process in the '70s and '80s, organic certification has become increasingly formalized and government-controlled. organic certification is a must-have for organic market access in more and more countries in the world, but is often not seen by producers to add much value beyond that. It claims to bring transparency and trust to the consumers, but it also delegates the judgment of agricultural practices to more or less anonymous entities. Certification is not designed to prevent fraud but it is expected to control and detect it. Organic certification and regulations are supposed to be tools to develop organic markets but at the same time create barriers to organic trade. Requirements for organic certification are continuously increasing and becoming more complex, yet organic certification is not seen as more reliable than it was a decade ago. Finally, standard setters are torn between the society's expectation that organic certification cover a wider range of sustainability topics, and the fear that more onerous requirements will inhibit conversion to Organic. All these paradoxes are becoming increasingly apparent as the organic movement reflects on how to scale up Organic Agriculture from a niche to the mainstream way of farming

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of ∼50 μas, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*’s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior

Actor Systems for Flexible, Scalable and Modular Simulation of Electrical Power Systems

International audienc

Multilevel A-Diakoptics for the Dynamic Power-Flow Simulation of Hybrid Power Distribution Systems

International audiencedoi: 10.1109/TII.2015.250654