Spin dynamics of FeGa3−x_{3-x}Gex_x studied by Electron Spin Resonance

The intermetallic semiconductor FeGa$_{3}$ acquires itinerant ferromagnetism upon electron doping by a partial replacement of Ga with Ge. We studied the electron spin resonance (ESR) of high-quality single crystals of FeGa$_{3-x}$Ge$_x$ for $x$ from 0 up to 0.162 where ferromagnetic order is observed. For $x = 0$ we observed a well-defined ESR signal, indicating the presence of pre-formed magnetic moments in the semiconducting phase. Upon Ge doping the occurrence of itinerant magnetism clearly affects the ESR properties below $\approx 40$~K whereas at higher temperatures an ESR signal as seen in FeGa$_{3}$ prevails independent on the Ge-content. The present results show that the ESR of FeGa$_{3-x}$Ge$_x$ is an appropriate and direct tool to investigate the evolution of 3d-based itinerant magnetism.Comment: 12 pages, 7 figure

The use of computer modelling to evaluate the agronomic, economic and environmental impacts of N management in contrasting organic rotations

A new computer model (EU-ROTATE_N) has been developed with the aim of improving nitrogen management on all farms across Europe which include fi eld vegetables in their rotations. It brings together aspects of many existing models and contains a number of features to make it applicable to organic producers (e.g. taking account of nitrogen fixation by legume containing leys, nitrogen conservation by winter cover crops and nitrogen supply by manures and composts). A key feature is the model’s ability to simulate economic output and this enables it to be of value to policy makers when considering the impact of new measures to reduce environmental pollution. This paper describes the model and some initial work that has been conducted to evaluate it under UK organic field vegetable systems with contrasting fertility building strategies

OrgTrace – No Difference in Levels of Bioactive Compounds found in Crops from Selected Organic and Conventional Cultivation Systems

The objective of the present study was to compare the content of selected bioactive compounds in organically and conventionally grown crops, and to evaluate if the ability of the crops to synthesize selected secondary metabolites was systematically affected by growth systems across different growth years as well as soil types. The results showed that contents of neither polyacetylenes and carotenoids in carrots, flavonoids in onions, nor phenolic acids in carrots and potatoes were significantly influenced by growth system. Thus it could not be concluded that the organically grown crops had higher contents of bioactive compounds than the conventionally grown. This indicates that giving preference to organic products because they contain more bioactive components is doubtfull. However, there are many other reasons for the consumer to choose organic food products, including: no pesticide residues in foods, animal welfare, and environmental protection

Environmental and economic modelling of organic, stockless, horticultural crop rotations

Selected results from the ongoing “EU-Rotate_N” research project are presented. This EU 5th-framework project is developing a model-based decision support system to optimise nitrogen use in horticultural crop rotations across Europe. This paper introduces the economic and the fertility-building crops sub-models, and shows data from model validation and first model runs on an organic farm in central England. Preliminary results show that the model has the potential to be a powerful support tool for farmers and advisors, making decisions on rotational plan-ning. The economic, agronomic and environmental consequences of different rotational designs can be projected and assessed in detail

Trade-off between value of landings and discard impact

Industries extracting natural resources are confronted with a trade-off between maximizing their income and limiting their impact on the ecosystem they exploit. Commercial fisheries produce negative impact via their pressure on the seabed and the additional mortality from discarding. One approach to limit the discarding impact is to introduce discard bans. The introduction of the Landing Obligation in the European Union is an example of this, and European fishers are currently under increased pressure to limit their unwanted catches which would previously have been discarded. Recent access to high resolution fishing data from sea-packing vessels has been made available to us from voluntary fishers in Denmark. The data contain size specific information at the haul level which makes it possible to calculate the expected value of the landings. Additionally, several of the vessels have discard data from a Remote Electronic Monitoring trial available to us too. Coupling these datasets we investigate the potential linkage between the value of landings compared with the discard impact generated by the fishing activities. Identifying discard hotspots and highlighting areas which generate high or low value to the fishers may detect scenarios where suboptimal decision making can be leveraged to optimize spatial selectivity and limit unwanted catches