Chaos and a Resonance Mechanism for Structure Formation in Inflationary Models

We exhibit a resonance mechanism of amplification of density perturbations in inflationary mo-dels, using a minimal set of ingredients (an effective cosmological constant, a scalar field minimally coupled to the gravitational field and matter), common to most models in the literature of inflation. This mechanism is based on the structure of homoclinic cylinders, emanating from an unstable periodic orbit in the neighborhood of a saddle-center critical point, present in the phase space of the model. The cylindrical structure induces oscillatory motions of the scales of the universe whenever the orbit visits the neighborhood of the saddle-center, before the universe enters a period of exponential expansion. The oscillations of the scale functions produce, by a resonance mechanism, the amplification of a selected wave number spectrum of density perturbations, and can explain the hierarchy of scales observed in the actual universe. The transversal crossings of the homoclinic cylinders induce chaos in the dynamics of the model, a fact intimately connected to the resonance mechanism occuring immediately before the exit to inflation.Comment: 4 pages. This essay received an Honorable Mention from the Gravity Research Foundation, 1998-Ed. To appear in Mod. Phys. Lett.

The mechanism for the electrooxidation of procarbazine pharmaceutical preparation in alkaline media and its mathematical description

The mechanism for the electrooxidation of procarbazine in alkaline media has been proposed. The process is realized completely on the electrode surface and is adsorption-controlled. The oscillatory behavior in this case is more probable, than for neutral media and may be caused by influences of electrochemical oxidation and salt dissolution from the electrode surface

Enfezamentos em milho: expressão de sintomas foliares, detecção dos molicutes e interações com genótipos.

Com o objetivo de verificar a multiplicacao, expressao de sintomas foliares e efeito dos molicutes na producao de diferentes genotipos de milho, fitoplasma e Spiroplasma kunkelii foram inoculados, isolada ou simultaneamente, em cinco cultivares, mantidas em vasos ate a producao. Plantas sadias de todas as cultivares foram utilizadas como controle. Em cada vaso, foram cultivadas duas plantas, sendo uma utilizada para a deteccao dos molicutes na ultima folha completamente expandida, aos 30, 60 e 100 dias apos a inoculacao. A outra planta foi utilizada para deteccao dos molicutes nas folhas inferiores, medianas e apicais, aos 100 dias apos a inoculacao. O percentual de reducao causado pelos molicutes na altura e na producao de graos foi determinado nas duas plantas, em relacao as plantas sadias. A expressao de sintomas foliares e os resultados positivos obtidos na deteccao dos molicutes foram mais evidentes aos 100 dias apos a inoculacao. O periodo de enchimento de graos foi considerado a fase mais adequada para a deteccao desses patogenos. Os molicutes foram detectados nas folhas inferiores, medianas e apicais, observando-se maior frequencia nas folhas apicais. Verificou-se predominancia de infeccao por espiroplasma e maior efeito detrimental desse patogeno no crescimento e producao das plantas em relacao ao fitoplasma. Nao foi detectado efeito sinergistico significativo dos dois molicutes sobre o crescimento e producao das plantas. Observou-se que o efeito prejudicial desses patogenos sobre o crescimento e producao das cultivares foi determinado pela frequencia de plantas infectadas

Entanglement and Bell's inequality violation above room temperature in metal carboxylates

In the present work we show that a special family of materials, the metal carboxylates, may have entangled states up to very high temperatures. From magnetic susceptibility measurements, we have estimated the critical temperature below which entanglement exists in the cooper carboxylate \{Cu$_2$(O$_2$CH)$_4$\}\{Cu(O$_2$CH)$_2$(2-methylpyridine)$_2$\}, and we have found this to be above room temperature ($T_e \sim 630$ K). Furthermore, the results show that the system remains maximally entangled until close to $\sim 100$ K and the Bell's inequality is violated up to nearly room temperature ($\sim 290$ K)

The mathematical description of the electrosynthesis of composites of oxy-hydroxycompounds cobalt with polypyrrole overooxidazed

The electrosynthesis of the composite with of the overoxidized polypyrrole with cobalt oxy-hydroxide in strongly acidic media has been described mathematically, using linear stability theory and bifurcation analysis. The steadystates stability conditions and oscillatory and monotonic instability requirements have been described too. The system´s behavior was compared with behavior of other systems with overoxidation, electropolymerization of heterocyclic compounds and electrosynthesis of the cobalt oxy-hydroxides

Symmetry breaking effects upon bipartite and multipartite entanglement in the XY model

We analyze the bipartite and multipartite entanglement for the ground state of the one-dimensional XY model in a transverse magnetic field in the thermodynamical limit. We explicitly take into account the spontaneous symmetry breaking in order to explore the relation between entanglement and quantum phase transitions. As a result we show that while both bipartite and multipartite entanglement can be enhanced by spontaneous symmetry breaking deep into the ferromagnetic phase, only the latter is affected by it in the vicinity of the critical point. This result adds to the evidence that multipartite, and not bipartite, entanglement is the fundamental indicator of long range correlations in quantum phase transitions.Comment: 13 pages, 19 figures, comments welcome. V2: small changes, published versio