4,393 research outputs found
Renormalized coordinate approach to the thermalization process
We consider a particle in the harmonic approximation coupled linearly to an
environment. modeled by an infinite set of harmonic oscillators. The system
(particle--environment) is considered in a cavity at thermal equilibrium. We
employ the recently introduced notion of renormalized coordinates to
investigate the time evolution of the particle occupation number. For
comparison we first present this study in bare coordinates. For a long ellapsed
time, in both approaches, the occupation number of the particle becomes
independent of its initial value. The value of ocupation number of the particle
is the physically expected one at the given temperature. So we have a Markovian
process, describing the particle thermalization with the environment. With
renormalized coordinates no renormalization procedure is required, leading
directly to a finite result.Comment: 16 pages, LATEX, 2 figure
Perfect category-graded algebras
In a perfect category every object has a minimal projective resolution. We
give a criterion for the category of modules over a categorygraded algebra to
be perfect.Comment: A sufficient condition is replaced by a criterion. Several references
added. 17 page
Environmental technology education in Portugal : analysis and perspectives
The scope of the present communication is the current status of environmental engineering in
Portugal. The different approaches concerning the environmental engineering courses available at
undergraduate levels as well as some post-graduation studies are described. Furthermore, an analysis
based on strengths, weakness, opportunities and trend issues regarding the environmental engineering
profession in Portugal is presented
Semioquímicos de plantas: integração da ecologia química e molecular no estudo da resposta da cna-de-açúcar à herbivoria.
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