Accuracy of various approximations to exchange and correlation for the electron density distribution in atoms and small molecules

The general usefulness of various local and non-local approximations to the exchange-correlation potential in density functional theory is studied by comparing resulting electron density distributions to essentially exact results for light atoms. The correlation contribution to the electron density in CO and H2O is compared with CI results. It is concluded that density functional theory provides a viable alternative to HF and CI approaches for the calculation of deformation densities, although the response of the electron density to the correlation potential is only moderately accurate

Proceedings of the OECD/PACIOLI Workshop on Information Needs for the Analysis of Farm Household Income Issues

The assessment of agricultural policies depends more and more on micro-economic data sets. This is especially true for policies with an income objective in a situation where farm households have different income sources. Among others the OECD has stressed this point in recent years with analytical reports. The PACIOLI network yearly brings together data managers and researchers interested in the innovation of data collection in this area. In April 2004 a joint workshop was organised at the OECD in Paris to bring experts together to exchange best practices. This report contains the proceedings of that workshop.Farm Management,

Nylon-6/rubber blends: 8. Influence of the molecular weight of the matrix on the impact behaviour

Blends of nylon-6 with polybutadiene were prepared with comparable morphology and different molecular weights of the matrix. These specimens were tested using the notched Izod impact test and the notched tensile impact test. An increase in molecular weight resulted in a shift of the brittle-to-tough transition temperature of 40°C to lower temperatures. In the notched tensile impact tests, especially in the high-speed region, pronounced differences between blends with different molecular weights of the matrix were observed

Support for farmers' cooperatives: EU synthesis and comparative analysis report: policy measures

In order to foster the competitiveness of the food supply chain, the European Commission is committed to promote and facilitate the restructuring and consolidation of the agricultural sector by encouraging the creation of voluntary agricultural producer organisations. To support the policy making process DG Agriculture and Rural Development has launched a large study, “Support for Farmers’ Cooperatives (SFC)”, that will provide insights on successful cooperatives and producer organisations as well as on effective support measures for these organisations. These insights can be used by farmers themselves, in setting up and strengthening their collective organisation, and by the European Commission in its effort to encourage the creation of agricultural producer organisations in the EU. Within the framework of the SFC project this EU synthesis and comparative analysis report - Policy Measures has been written. Data collection for this report has been done in the summer of 2011. In addition to this report, the SFC-project has delivered 27 country reports, a report on policies for cooperatives in non-EU OECD countries, 8 sector reports, 5 other EU synthesis and comparative analysis reports, 33 case studies, a report on cluster analysis, and a final report

On the feasibility of RADAR detection of high-energy neutrino-induced showers in ice

In this article we try to answer the question whether the radar detection technique can be used for the detection of high-energy-neutrino induced particle cascades in ice. A high-energy neutrino interacting in ice will induce a particle cascade, also referred to as a particle shower, moving at approximately the speed of light. Passing through, the cascade will ionize the medium, leaving behind a plasma tube. The different properties of the plasma-tube, such as its lifetime, size and the charge-density will be used to obtain an estimate if it is possible to detect this tube by means of the radar detection technique. Next to the ionization electrons a second plasma due to mobile protons induced by the particle cascade is discussed. An energy threshold for the cascade inducing particle of 4 PeV for the electron plasma, and 20 PeV for the proton plasma is obtained. This allows the radar detection technique, if successful, to cover the energy-gap between several PeV and a few EeV in the currently operating neutrino detectors, where on the low side IceCube runs out of events, and on the high side the Askaryan radio detectors begin to have large effective volumes

Electrostatic interactions in host-guest complexes 2

In this article the quantum chemically calculated charge density distribution of 18-crown-6 and the K+ 18-crown-6 complex are compared with the charge density distribution of smaller molecules and corresponding complexes which can be considered as fragments of the 18-crown-6 molecule. An analysis of the charge density distribution in terms of atomic charge distribution according to the stockholder recipe gives accurate rules for the transferability of the charge density distribution. This gives us the possibility to construct the charge density distribution of large molecules out of accurate large basis set results on small molecules

The air shower maximum probed by Cherenkov effects from radio emission

Radio detection of cosmic-ray-induced air showers has come to a flight the last decade. Along with the experimental efforts, several theoretical models were developed. The main radio-emission mechanisms are established to be the geomagnetic emission due to deflection of electrons and positrons in Earth's magnetic field and the charge-excess emission due to a net electron excess in the air shower front. It was only recently shown that Cherenkov effects play an important role in the radio emission from air showers. In this article we show the importance of these effects to extract quantitatively the position of the shower maximum from the radio signal, which is a sensitive measure for the mass of the initial cosmic ray. We also show that the relative magnitude of the charge-excess and geomagnetic emission changes considerably at small observer distances where Cherenkov effects apply

Adjustment and differences in farm performance; A farm management perspective from the Netherlands

There are differences in performance between farmers. In the Netherlands this has been a major topic of research for at least 30 years. Research has shown that the managerial capacities of farmers play a major role in differences in economic and environmental performance. Management can be measured and the optimal level is not the maximum level. Farmers differ in their objectives, competences and local external situation and there-fore their strategies. These strategies can be identified. In recent years strategic management has become more important and this can be supported with consultancy. Farmers also differ in their adoption and innovation behaviour. These micro-economic results, which correlate with large differences in income and high prices of fixed assets with a limited supply, can be explained as being consistent with economic theory on perfect markets. Although these findings suggest that some farm households have attractive strategies that can cope with policy adjustments, the research supports the hypothesis but does not (yet) prove that a severe adjustment of agricultural policy e.g. towards a more market oriented policy, induces more innovation, and that due to this innovation the effects of adjusting the agricultural policy are less severe than estimated ex ante with current dynamic policy models.Farm Management,