977 resultados para Nontariff trade barriers
Resumo:
1. We examine whether various measures of herbivore current physiological state (age, breeding and immune status) and genetic potential can be used as indicators of exposure to and risk from disease. We use dairy cattle and the risks of tuberculosis (TB) transmission posed to them by pasture contaminated with badger excreta (via the fecal-oral route) as a model system to address our aim.
Resumo:
Density functional theory calculations are used to study the stability of molecularly adsorbed CO and CN over transition metal surfaces. The minimum energy reaction pathways, corresponding reaction barriers (E-a), and reaction enthalpies (Delta H) for the dissociation of CO and CN to atomic products over the 4d transition metals from Zr to Pd have been determined. CO is found to be the more stable adsorbate on the right hand side of the period (from Tc onwards), whereas CN is the more stable surface species on the early metals (Zr, Nb and Mo). A single linear relationship is found to exist that correlates the barriers of both reactions with their respective reaction enthalpies. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
A catalyst preparation by design is one of the ultimate goals in chemistry. The first step towards this goal is to understand the origin of reaction barriers. In this study, we have investigated several catalytic reactions on some transition metal surfaces, using density functional theory. All the reaction barriers have been determined. By detailed analyses we obtain some insight into the reaction barrier. Each barrier is related to (i) the potential energy surface of reactants on the surface, (ii) the total chemisorption energy of reactants, and (iii) the metal d orbital occupancy and the reactant valency. (C) 2001 American Institute of Physics.
Resumo:
This paper explores the historical development of POE in order to provide a contextual backdrop to current discussions. This review provides a much needed discussion on the benefits and barriers facing POE which should enable designers, facility managers and building users to appreciate the value and purpose of this important building evaluation process. The paper will encourage architects and building owners to conduct POEs to benefit all stakeholders and future designs. This is an international peer reviewed journal.
Resumo:
The notion that the EU is a trade power is central to studies of the Union’s international presence. Credible threats to withhold access to Europe’s markets are said to provide the Union with leverage in respect of other trade partners. This paper queries the continuing ability of the European Union to act effectively this way. The current Doha malaise is a symptom of deeper changes in the international trade system. As emerging markets become more affluent and participate in foreign direct investment, their interest in market access per se become less important relative to other areas of regulation.