Universal behavior in a model of city traffic with unequal green/red times

The effect of green/red asymmetry is studied for the single-car traffic model proposed in [B.A. Toledo, V. Muñoz, J. Rogan, C. Tenreiro, J.A. Valdivia, Modeling traffic through a sequence of traffic lights, Phys. Rev. E 70 (1) (2004) 016107], on two different signal synchronization strategies, namely, all signals in phase, and a green wave. The asymmetry is characterized by the parameter g=_tgr/T$g=t_{\text{gr}}/T$, where _tgr$t_{\text{gr}}$ is the green time and T$T$ the signal period. Although the car dynamics turns simpler or more complex, as compared with the equivalent situation for the symmetric case g=0.5$g=0.5$, critical behavior around resonance is shown to be preserved. However, unlike the case g=0.5$g=0.5$, critical exponents at both sides of the resonance are not equal and depend on g$g$. Analytical expressions for them are found, and shown to be both consistent with simulation results and independent of the distribution of distances between signals for the green wave case. Also, it is found that the green wave strategy is more robust to changes in g$g$, with respect to the synchronized lights strategy, in the sense that larger departures from g=0.5$g=0.5$ are needed to have noticeable effects on the car dynamics.     

Kernel theorems in the setting of mixed nonquasi-analytic classes

Let Ω₁⊂Rr and Ω₂⊂Rs be nonempty and open. We introduce the Beurling-Roumieu spaces D(ω₁,ω₂}(Ω₁×Ω₂), D(M,M^′}(Ω₁×Ω₂) and obtain tensor product representations of them. This leads for instance to kernel theorems of the following type: every continuous linear map from the Beurling space D(ω₁)(Ω₁) (respectively D(M)(Ω₁)) into the strong dual of the Roumieu space D{ω₂}(Ω₂) (respectively D{M^′}(Ω₂)) can be represented by a continuous linear functional on D(ω₁,ω₂}(Ω₁×Ω₂) (respectively D(M,M^′}(Ω₁×Ω₂)).     

Ultraviolet laser-induced sub-micron periodic domain formation in congruent undoped lithium niobate crystals

We report the formation of ordered sub-micron periodic surface domains on the –z face of congruent undoped lithium niobate single crystals induced by pulsed ultraviolet laser illumination of the sample faces under specific irradiation conditions. We demonstrate the utility of this simple light-induced technique for achieving periodic domain inversion and investigate the nature and spatial structure of these nano-domains by scanning force microscopy. We also demonstrate subsequent re-inversion of a small region of these light-induced nano-domains using scanning force microscopy.     

On certain classes of Markushevich bases

Supported in part by DGICYT P.B. 91-0326.     

Projective resolution of identity inC(K) spaces

Support in part by CAICYT.