70 research outputs found
A functional central limit theorem for interacting particle systems on transitive graphs
Abstract A nite range interacting particle system on a transitive graph is considered. Assuming that the dynamics and the initial measure are invariant, the normalized empirical distribution process converges in distribution to a centered diusion process. As an application, a central limit theorem for certain hitting times, interpreted as failure times of a coherent system in reliability, is derived
European agricultural landscapes, common agricultural policy and ecosystem services: a review
Since the 1950s, intensification and scale enlargement of agriculture have changed agricultural landscapes across Europe. The intensification and scale enlargement of farming was initially driven by the large-scale application of synthetic fertilizers, mechanization and subsidies of the European Common Agricultural Policy (CAP). Then, after the 1990s, a further intensification and scale enlargement, and land abandonment in less favored areas was caused by globalization of commodity markets and CAP reforms. The landscape changes during the past six decades have changed the flows and values of ecosystem services. Here, we have reviewed the literature on agricultural policies and management, landscape structure and composition, and the contribution of ecosystem services to regional competitiveness. The objective was to define an analytical framework to determine and assess ecosystem services at the landscape scale. In contrast to natural ecosystems, ecosystem service flows and values in agricultural landscapes are often a result of interactions between agricultural management and ecological structures. We describe how land management by farmers and other land managers relates to landscape structure and composition. We also examine the influence of commodity markets and policies on the behavior of land managers. Additionally, we studied the influence of consumer demand on flows and values of the ecosystem services that originate from the agricultural landscape
Electrochemical oxidation of succinic acid in aqueous solutions using boron doped diamond anodes
In this work, the electrochemical oxidation of succinic acid on
boron-doped diamond (BDD) anodes was investigated. Voltammetric study
had shown that no peaks appeared in the region of electrolyte stability
which indicates that succinic acid oxidation can take place at a
potential close to the potential region of electrolyte oxidation.
Galvanostatic electrolyses achieved total chemical oxygen demand (COD)
removals and high mineralization yields under different operating
conditions (initial COD, current density and nature of supporting
electrolyte). Oxalic, glycolic and formic acids were the main
intermediates detected during anodic oxidation of succinic acid on BDD
electrode and carbon dioxide as the final product. The mean oxidation
state of carbon reached the value of 4 at the end of electrolysis which
is indicative of mineralization of almost all organics present in
aqueous solution. The exponential profile of COD versus specific
electrical charge has shown that mass transfer is the limiting factor
for the kinetics of electrochemical process. A simple mechanism was
proposed for the mineralization of succinic acid. First, hydroxyl
radicals attack of succinic acid leading to formation of glycolic,
glyoxylic, fumaric and maleic acids. Then, theses acids undergo rapid
and non-selective oxidation by hydroxyl radicals to be transformed into
oxalic and formic acids which leads to further oxidation steps to
mineralize these acids into carbon dioxide and water
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