RESUMEN
Coherent transport phenomena are difficult to observe due to several sources of decoherence. For instance, in the electronic transport through quantum devices the thermal smearing and dephasing, the latter induced by inelastic scattering by phonons or impurities, destroy phase coherence. In other wave systems, the temperature and dephasing may not destroy the coherence and can then be used to observe the underlying wave behaviour of the coherent phenomena. Here, we observe coherent transmission of mechanical waves through a two-dimensional elastic Sinai billiard with two waveguides. The flexural-wave transmission, performed by non-contact means, shows the quantization when a new mode becomes open. These measurements agree with the theoretical predictions of the simplest model highlighting the universal character of the transmission fluctuations.
RESUMEN
A systematic study of the effect of design and operation conditions of an electrochemical reactor on the treatment time for arsenic (As) electro-removal from underground water (GW) was carried out to analyse the energy and electrode consumption. The effects of four factors--current density, interelectrode distance, electrode area-volume ratio, and liquid motion driving mode--were evaluated. The response variables were the energy and the electrode consumption and the treatment time to reduce the GW residual As concentration to 10 microg L(-1), which is the maximum contaminant level (MCL) established by the World Health Organization (WHO) in drinking water. The results obtained in this study showed that the factor that had the greatest effect on most of the response variables was the liquid motion driving mode. The best residence time was 20s, which favoured low energy consumption (58.78 Wh m(-3)) and low electrode material loss (9.59 g m(-3)).
Asunto(s)
Arsénico/aislamiento & purificación , Electrocoagulación/métodos , Contaminantes del Agua/aislamiento & purificación , Purificación del Agua/métodos , Abastecimiento de Agua/normas , Electricidad , Electrodos , Agua Dulce/química , Organización Mundial de la SaludRESUMEN
Se realizó un estudio abierto, no controlado, multicéntrico, realizado con intención de tratar, en 60 pacientes con dorsolumbalgia mecánica, en el cual evaluó la efectividad y seguridad de nimesulide 100 mg dos veces al día, administrado durante 15 días. El tratamiento produjo un alivio significativo en los escores de dolor entre el día de inicio del tratamiento y los 5 días, con un alivio adicional importante entre los días 5 y 10, sin alivios adicionales para el día 15. El tiempo medio para la desaparición total del dolor fue de 8,5 días. La limitación funcional fue evaluada el día 0 y el día 15, obteniéndose una mejoría significativa desde el punto de vista estadístico. Se reportaron efectos adversos en 4 de los pacientes, de los cuales sólo uno ameritó la suspensión del tratamiento