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Los objetivos principales son describir la práctica de la ventilación mecánica en un periodo de 18 años en México y estimar los cambios en la mortalidad de los pacientes críticos con ventilación mecánica invasiva (VMI).

We show that third-order dispersion, filtering, and amplification in a fiber Bragg grating dispersion-managed soliton system can lead to the formation of bound multisoliton solutions. We have found that these solutions appear due to the presence of nonsymmetrical terms in the transfer function of chirped gratings. We present an analytical approximation for the time delay of a chirped grating in the vicinity of the central frequency that takes into account higher-order dispersion terms. We also study the tolerance of these newly found multisoliton solutions to the presence of third-order dispersion in the fiber link and to random variations in the gratings parameters due to manufacture or variations in the operating conditions.

We present experimental demonstration of a 200-km-long, dual-wavelength Raman laser utilizing two slightly different-wavelength fiber Bragg gratings, one on each side of the fiber span. The obtained results clearly prove the generation of two independent Raman lasers with a distributed “random” Rayleigh scattering mirror forming a cavity together with each of the individual fiber Bragg grating reflectors.

We present the first experimental demonstration (to our knowledge) of long-distance unperturbed fundamental optical soliton transmission in conventional single-mode optical fiber. The virtual transparency in the fiber required for soliton transmission, over 15 complete periods, was achieved by using an ultralong Raman fiber laser amplification scheme. Optical soliton pulse duration, pulse bandwidth, and peak intensity are shown to remain constant along the transmission length. Frequency-resolved optical gating spectrograms and numerical simulations confirm the observed optical soliton dynamics.

We present the first experimental demonstration of a resolvable mode structure with spacing c/2nL in the RF spectra of ultralong Raman fiber lasers. The longest ever demonstrated laser cavity (L=84 km), RF peaks of ∼100 Hz width and spacing ∼1 kHz have been observed at low intracavity powers. The width of the peaks increases linearly with growing intracavity power and is almost independent of fiber length.

We have studied the propagation of prechirped Gaussian pulse pairs in a fiber Bragg grating dispersion-managed system. We discovered that, under quite general conditions, a number of individual pulses evolve to a stable bound multisoliton solution, with fixed values for the phase difference and the distance between adjacent pulses. These stable multisoliton solutions may propagate for long distances without deformation, with the ultimate distance limitation imposed by the noise amplification.