RESUMO
The behavior of the marginal power spectrum as a two-channel-multiplexed hologram is analyzed. Its "negative energies" make it quite different from the conventional holograms, i.e., it is not recordable in general and the objects to be reconstructed (the cross-spectral densities at both the aperture and the observation planes) are virtual. The holographic reconstruction results from the superposition of the spatial coherence wavelets that carry the marginal power spectrum. These features make the marginal power spectrum a powerful tool for analysis and synthesis of optical fields, for instance, in optical information processing (signal encryption) and beam shaping for microlithography.
RESUMO
A moiré-effect-based procedure used to measure the wavelength of coherent sources is shown. Two plane waves, individually coherent but mutually incoherent and located at the entrance pupil of a Michelson interferometer with slightly tilted mirrors, generate a moiré pattern at the output plane. The spatial period of that moiré pattern is determined by the spatial frequencies of the interferograms superimposed on intensity. Thus the spatial frequency of such moiré patterns allows the establishment of a ratio between the wavelengths of the sources that illuminate the interferometer. This ratio can be applied for the accurate determination of determining an unknown wavelength in terms of a reference wavelength, as we show both theoretically and experimentally.
RESUMO
Se presenta el manejo de 20 casos de luxofractura de Monteggia en niños, que fueron atendidos en los últimos tres (3) años; 70 por ciento fueron tipo III; 14 pacientes se atendieron en su fase aguda y 6 fueron inveterados. Sus resultados se evaluaron de acuerdo a los criterios de Bruce; fueron 100 por ciento satisfactorios en los casos agudos manejados cerrada o quirúrgicamente, pero solamente el 25 por ciento de los casos inveterados fueron satisfactorios. Se hace un análisis de los resultados y se formulan recomendaciones de manejo