Origens dos instrumentos de formação da política comercial norte-americana

L'objectif de cet article est de montrer l'existence de traces historiques permettant de lier les concepts de libre-échange et protectionnisme, tous les deux employés dans la politique de commerce extérieur des Etats-Unis. Parallèlement, on cherche à souligner l'importance de la législation et des principes formulés dans ce pays et leur rôle explicatif concernant les motivations de la structure du commerce international après 1945. Ce rôle a en effet contribué à qu'on puisse mieux comprendre les tournées de négociations du GATT (General Agreement on Tariffs and Trade) jusqu'à la création de l'OMC (Organisation Mondiale du Commerce), en 1995. on traite également des raisons pour lesquelles le commerce international aux Etats-Unis est non seulement une question d'Etat mais encore une question de la société.

A influência da Segunda Guerra Mundial na produção literária de Saint- Exupéry

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Photoelastic analysis of forces generated by T-loop springs made with stainless steel or titanium-molybdenum alloy

Introduction: The purpose of this study was to use photoelastic analysis to compare the system of forces generated by retraction T-loop springs made with stainless steel and titanium-molybdenum alloy (TMA) (Ormco, Glendora, Calif) with photoelastic analysis. Methods: Three photoelastic models were used to evaluate retraction T-loop springs with the same preactivations in 2 groups. In group 1, the loop was constructed with a stainless steel wire, and 2 helicoids were incorporated on top of the T-loop; in group 2, it was made with TMA and no helicoids. Results: Upon using the qualitative analysis of the fringe order in the photoelastic model, it was observed that the magnitude of force generated by the springs in group 1 was significantly higher than that in group 2. However, both had symmetry for the active and reactive units related to the system of force. Conclusions: Both springs had the same mechanical characteristics. TMA springs showed lower force levels. (Am J Orthod Dentofacial Orthop 2011;140:e123-e128)

Higgs- and Goldstone-boson-mediated long range forces

In certain mild extensions of the standard model, spin-independent long range forces can arise by exchange of two very light pseudoscalar spin-0 bosons. In particular, we have in mind models in which these bosons do not have direct tree level couplings to ordinary fermions. Using the dispersion theoretical method, we find a 1/r3 behavior of the potential for the exchange of very light pseudoscalars and a 1/r7 dependence if the pseudoscalars are true massless Goldstone bosons. ©1999 The American Physical Society.

Long range neutrino forces in the cosmic relic neutrino background

Neutrinos mediate long range forces among macroscopic bodies in a vacuum. When the bodies are placed in the neutrino cosmic background, these forces are modified. Indeed, at distances long compared to the scale T -1, the relic neutrinos completely screen off the two-neutrino exchange force, whereas for small distances the interaction remains unaffected. ©2000 The American Physical Society.