[Sickness absence certification from the medical perspective]. / La incapacidad temporal para el trabajo desde la perspectiva médica.

Sickness absence certification is a medical task with important clinical, social, occupational and ethical implications, in addition to economic consequences for the worker, the employers and social security institutions. In 2007, IMSS affiliated workers received certifications for 65,384,690 days of absence, with cash benefits for 8.1 billion pesos. The duration of return to work depends on the efficiency of health care team as well as factors associated to the worker and the occupational environment. The correct management of sickness absence certification requires adequate disease diagnosis, regulatory knowledge and adequate communication with the patient. The purpose of control and auditing is to make sure that the certification is adequate in the indication and the optimal length, in order to warrant a responsible and sustainable management of this resource of social protection. If expenditure reduction is not possible, the objective is to avoid inefficient or irrational management. Treating physicians, with proper information, can contribute to optimize the provision of this benefit to those who need it.

Multiple surface-plasmon resonance in uniform-waist tapered optical fibers with an asymmetric double-layer deposition.

Novel devices consisting of uniform-waist tapered optical fibers with asymmetric double-layer (metal plus dielectric) depositions have been recently proposed as refractive-index sensors. We study the properties of light transmission by use of this kind of devices, and we specifically perform a detailed study of the generation of surface-plasma waves in the structures. We show that multiple surface plasmons are excited for specific combinations of the constructive parameters of the devices and for specific ranges of the refractive index of the surrounding medium. The behavior also depends on the wavelength and the state of polarization of the incident light. The use of uniform-waist tapers allows for control of constructive parameters and an increase in the interaction length with the outer medium. We show how the plasmons are excited in the region of the taper waist by a coupling with the cladding modes guided in that area. This characterization shows the importance of the presence of a dielectric layer for selection of the operating range of the device. The results are useful for the design of new sensors.

Sensing properties of asymmetric double-layer-covered tapered fibers.

A novel, to our knowledge, device based on a tapered optical fiber with a double-layer deposition including a metallic media is presented, and its properties are studied. The main novelty of the device consists of the introduction of a dielectric layer, whereas the systems depicted in the literature are simply metal-coated tapered fibers. The presence of the dielectric layer permits one to tune the response of the device to the refractive index of the surrounding medium. We have proved the suitability of this scheme for refractive-index sensing by depicting two measurement modes, namely, total power attenuation and spectral transmittance.