Environmental assessment tools for the evaluation and improvement of European livestock production systems

Different types of assessment tools have been developed in Europe with the purpose of determining the environmental impact of various livestock production systems at farm level. The assessment tools differ in terms of which environmental objectives are included and how indicators are constructed and interpreted. The paper compares typical tools for environmental assessment of livestock production systems, and recommends selected indicators suitable for benchmarking. The assessment tools used very different types of indicators ranging from descriptions of farm management and quantification of input to estimates of emissions of, e.g., nitrate and ammonia. The indicators should be useful in a benchmarking process where farmers may improve their practices through learning from farms with better agri-environmental performance. An example of this is given using data on P-surplus on pig farms. Some indicators used the area of the farm as the basis of the indicator — e.g. nitrogen surplus per hectare — while others were expressed per unit produced, e.g. emission of greenhouse gasses per kilogram milk. The paper demonstrates that a comparison of organic vs. conventional milk production and comparison of three pig production systems give different results, depending on the basis of the indicators (i.e. per hectare or per kilogram product). Indicators linked to environmental objectives with a local or regional geographical target should be area-based — while indicators with a global focus should be product-based. It is argued that the choice of indicators should be linked with the definition of the system boundaries, in the sense that area-based indicators should include emissions on the farm only, whereas product-based indicators should preferably include emissions from production of farm inputs, as well as the inputs on the actual farm. The paper ends with recommendations for choice of agri-environmental indicators taking into account the geographical scale, system boundary and method of interpretation

Interruption of torus doubling bifurcation and genesis of strange nonchaotic attractors in a quasiperiodically forced map : Mechanisms and their characterizations

A simple quasiperiodically forced one-dimensional cubic map is shown to exhibit very many types of routes to chaos via strange nonchaotic attractors (SNAs) with reference to a two-parameter $(A-f)$ space. The routes include transitions to chaos via SNAs from both one frequency torus and period doubled torus. In the former case, we identify the fractalization and type I intermittency routes. In the latter case, we point out that atleast four distinct routes through which the truncation of torus doubling bifurcation and the birth of SNAs take place in this model. In particular, the formation of SNAs through Heagy-Hammel, fractalization and type--III intermittent mechanisms are described. In addition, it has been found that in this system there are some regions in the parameter space where a novel dynamics involving a sudden expansion of the attractor which tames the growth of period-doubling bifurcation takes place, giving birth to SNA. The SNAs created through different mechanisms are characterized by the behaviour of the Lyapunov exponents and their variance, by the estimation of phase sensitivity exponent as well as through the distribution of finite-time Lyapunov exponents.Comment: 27 pages, RevTeX 4, 16 EPS figures. Phys. Rev. E (2001) to appea

Folate Synthesis and Metabolism in Plants and Prospects For Biofortification

Folates are essential cofactors for one-carbon transfer reactions in most living organisms and are required for the biosynthesis of nucleic acids, amino acids, and pantothenate. Unlike plants and microorganisms, humans cannot synthesize folates de novo and must acquire them from the diet, primarily from plant foods. However, lack of folates is the most common vitamin deficiency in the world and has serious health consequences, including increased risk of neural tube defects in infants, cancers, and vascular diseases. Consequently, there is much interest in engineering plants with enhanced folate content (biofortification). In this review, we outline progress in defining the plant folate synthesis pathway and its unique progress in defining the plant folate synthesis pathway and its unique compartmentation and point out sectors of folate metabolism that have yet to be elucidated, including transport and catabolism. We also consider possible strategies to enhance plant folate synthesis and accumulation by metabolic engineering

Production of Hydrogen from water by photocatalysis using M/TI02 M=Pt, Pd, Au, Rh, Ru, Ni, Ir

International @ EAU+EPUInternational audienceNon

Homogeneous catalysis in water (III). The catalytic hydrogenation of propionaldehyde with [RuCl2L2]2, RuHClL3, RuH(OAc)L3, RuH2L4, RuHIL3, RuCl2(CO)2L2, and [Ru(OAc)(CO)2L]2 (L=P(C6H4-m-SO3Na)3.3H2O). A kinetic investigation of salt effect in water

Seven water-soluble ruthenium complexes (RuCl2L2)2 1, RuHClL3 2, RuH(OAc)L3 3, RuH2L4 4, RuHIL3 5, RuCl2(CO)2L2 6 and [Ru(OAc)(CO)2L]2 7 (L-P(C6H4–mSO3Na)3·3H2O) have been tested in the catalytic hydrogenation of propionaldehyde. Their catalytic performances have been compared to those of their organosoluble analogues (1′–7′, L-PPh3). The non-carbonylated complexes 1–5 exhibit comparable rates of propionaldehyde hydrogenation in water at 100 °C, as determined by their first-order rate constants. In contrast, the rates observed with 1′–4′ are different from one another and extremely solvent dependent. With 1, the reaction is first order in aldehyde, catast and hydrogen pressure, as is found for the organosoluble complex RuH(CO)Cl(PPh3)3. Starting with 1–4, various equilibria have been observed which lead to the same complex RuH2L3(H2O). These equilibria suggest that the real catalyst precursor in water is RuH2L3. Whatever the precursor (1–5) used, addition of alkaline, alkaline-earth and ammonium salt dramatically increases the activity without any loss of selectivity. The rate equation is drastically modified in the presence of salt. It has been established that the salt acts by both its cation and its anion. For a given anion, the rate increases in the order: NR4+ (R-Et, n-Bu)Na+Li+K+Mg2+Ca2+. For a given cation, the rate increases in the order: SiF62−NO3−Cl−Br−I−. In the presence of NaI, the coordination spheres of 2-4 are modified in water and lead to the same complex RuHIL3 5. The role of the cation has been verified by adding to the catalytic solution a specific sodium cryptand, which resulted in a dramatic drop in activity. A mechanism has been proposed which takes into account the kinetic equation as well as the various observations which were made on the different catalyst precursors