49 research outputs found

    'Met techniek is al veel verbeterd'

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    Om de Nederlandse veehouderij aan de toekomstige eisen op het gebied van milieu en dierenwelzijn te laten voldoen, moet er nog van alles gebeuren. Maar pas op met al te veel pessimisme over wat techniek vermag, zegt onderzoeker Nico Verdoes van Wageningen UR Livestock Research. Door stap voor stap de veehouderij te verbeteren is er de afgelopen decennia veel bereikt

    On the interpretation of spin-polarized electron energy loss spectra

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    We study the origin of the structure in the spin-polarized electron energy loss spectroscopy (SPEELS) spectra of ferromagnetic crystals. Our study is based on a 3d tight-binding Fe model, with constant onsite Coulomb repulsion U between electrons of opposite spin. We find it is not the total density of Stoner states as a function of energy loss which determines the response of the system in the Stoner region, as usually thought, but the densities of Stoner states for only a few interband transitions. Which transitions are important depends ultimately on how strongly umklapp processes couple the corresponding bands. This allows us to show, in particular, that the Stoner peak in SPEELS spectra does not necessarily indicate the value of the exchange splitting energy. Thus, the common assumption that this peak allows us to estimate the magnetic moment through its correlation with exchange splitting should be reconsidered, both in bulk and surface studies. Furthermore, we are able to show that the above mechanism is one of the main causes for the typical broadness of experimental spectra. Finally, our model predicts that optical spin waves should be excited in SPEELS experiments.Comment: 11 pages, 7 eps figures, REVTeX fil

    Adsorption of CO on a Platinum (111) surface - a study within a four-component relativistic density functional approach

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    We report on results of a theoretical study of the adsorption process of a single carbon oxide molecule on a Platinum (111) surface. A four-component relativistic density functional method was applied to account for a proper description of the strong relativistic effects. A limited number of atoms in the framework of a cluster approach is used to describe the surface. Different adsorption sites are investigated. We found that CO is preferably adsorbed at the top position.Comment: 23 Pages with 4 figure

    Not all puppies and sunshine: how dog keepers cope with dog-related problems in Dutch society

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    Zoonoses, biting incidents, hereditary problems, and other issues can threaten the welfare of both humans and dogs. The Dutch government and animal welfare organizations seem to have little effect in their campaigns to influence the behavior of (potential) dog keepers, who can experience dissonance when faced with these campaigns and use coping strategies to relieve the dissonance instead of changing their behavior. In this study, in focus group discussions, dog keepers with pedigree dogs, high-risk dogs, foreign shelter dogs, and dogs purchased at puppy farms shared their experiences with opinions on dogs and were confronted with negative opinions on their dogs. The data were analyzed using a coping strategies framework. Most coping strategies were found in all groups, but were used in response to different dilemmas, with different manifestations. These differences should be kept in mind when behavior change in dog keepers is opportune. Special attention should be given to differentiating target groups, as use of the detachment coping strategy suggests that boundaries might be set differently than expected. Broad attention on problems with and for dogs can address perceived dissonance and prompt behavior change. In dialogue with dog keepers, in influential campaigns and in policy formulation, the chances of success are greater if initiators are aware of the strategies that they may encounter
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