Contractions, Hopf algebra extensions and cov. differential calculus

We re-examine all the contractions related with the ${\cal U}_q(su(2))$ deformed algebra and study the consequences that the contraction process has for their structure. We also show using ${\cal U}_q(su(2))\times{\cal U}(u(1))$ as an example that, as in the undeformed case, the contraction may generate Hopf algebra cohomology. We shall show that most of the different Hopf algebra deformations obtained have a bicrossproduct or a cocycle bicrossproduct structure, for which we shall also give their dual `group' versions. The bicovariant differential calculi on the deformed spaces associated with the contracted algebras and the requirements for their existence are examined as well.Comment: TeX file, 25 pages. Macros are include

Emprego e adaptação do método GMP-RAM para avaliação dos riscos das nanotecnologias.

Resumo: A Nanotecnologia está baseada na crescente capacidade da tecnologia moderna em manipular átomos e partículas na nanoescala para criar novos materiais e desenvolver novos produtos e processos. Ela promete grandes avanços nas mais diversas áreas de atuação, desde a Medicina à Engenharia de Materiais. Apesar dos materiais nanoestruturados apresentarem propriedades físicas diferentes do seu correspondente convencional, ainda não há metodologias para avaliação de riscos direcionadas ao uso intensivo desses novos materiais e substâncias químicas. Neste cenário, o presente trabalho propõe o emprego e adequação de uma metodologia comumente empregada para a avaliação de risco de transgênicos para o caso das nanotecnologias. O método GMP-RAM já foi empregado com sucesso para o caso do mamão geneticamente modificado para resistência ao vírus da mancha anelar. Abstract: Nanotechnology is based on the increasing power of modern technology to manipulate atoms and particles at the nanoscale to create new materials and develop new products and processes. It promises great advances in several areas of expertise, from medicine to Materials Engineering. Although engineered nanomaterials present different physical properties of its corresponding conventional, there are no methodologies for risk assessment to determine the intensive use of these new materials and chemicals. In this scenario, this study proposes the use and adequacy of a methodology commonly used for the risk assessment of transgenic for the case of nanotechnology. The GMP-RAM Method has already been used successfully to perform the case study of the papaya genetically modified for resistance to the ringspot virus.bitstream/item/52419/1/boletim-62.pd

Effective actions, relative cohomology and Chern Simons forms

The explicit expression of all the WZW effective actions for a simple group G broken down to a subgroup H is established in a simple and direct way, and the formal similarity of these actions to the Chern-Simons forms is explained. Applications are also discussed.Comment: 11 pages. Latex2e file. Published versio