297 research outputs found
Closed universes can satisfy the holographic principle in three dimensions
We examine in details Friedmann-Robertson-Walker models in 2+1 dimensions in order to investigate the cosmic holographic principle suggested by Fischler and Susskind. Our results are rigorously derived differing from the previous one found by Wang and Abdalla. We discuss the erroneous assumptions done in this work. The matter content of the models is composed of a perfect fluid, with a -law equation of state. We found that closed universes satisfy the holographic principle only for exotic matter with a negative pressure. We also analyze the case of a collapsing flat universe
Current Algebra in the Path Integral framework
In this letter we describe an approach to the current algebra based in the
Path Integral formalism. We use this method for abelian and non-abelian quantum
field theories in 1+1 and 2+1 dimensions and the correct expressions are
obtained. Our results show the independence of the regularization of the
current algebras.Comment: 8 pages, Revtex. One reference added. To appear in Mod. Phys. Lett.
A, Vol. 13, No. 27 (1998
Sensorial repercussions of the formation of vinylphenolic pyranoanthocyanins
Using selected yeast, of the Saccharomyces cerevisiae specie, with hydroxycinnamate decarboxylase activity (HCDC+) we can transform anthocyanidin-3-O-glucosides from grapes into vinylphenolic pyranoanthocyanins. Saccaromyces cerevisiae don’t posses vinylphenol reductase activity (VPhR), however some yeast strains belonging to this specie are HCDC+. The selection of Saccharomyces cerevisiae strains HCDC+ with suitable fermentative and metabolic properties to red wine making allow us to stabilize the wine anthocyanins forming resistant pyranoanthocyanins. A relevant repercussion is that removing of hydroxycinnamic acids from musts we can avoid the formation of ethylphenols in red wine contaminated with the spoiling yeast Dekkera/Brettanomyces during barrel ageing. During in-vitro experiments we reduce notably the initial concentrations of 12 mg l-1 of p-coumaric acid, allowing can be below the detection limit in many vinifications
- …