Abnormal spectral evolution of fiber Bragg gratings in hydrogenated fibers

The properties of fiber Bragg gratings in hydrogenated fibers under conditions of ultraviolet overexposure were investigated. Abnormal spectral evolution of the regenerated grating following erasure of the initial type I grating was observed in the hydrogenated fibers. The regenerated grating also exhibited less temperature sensitivity and an 18 nm shift in the Bragg wavelength

Bidirectional nonreciprocal wavelength-interleaving coherent fiber transversal filter

A bidirectional nonreciprocal wavelength-interleaving filter based on an optically coherent high birefringence fiber transversal filter structure is demonstrated. Stable, low loss, low dispersion, and high isolation operation is demonstrated with reconfigurable transfer characteristics for interleaved channel spacing of 0.8 nm

Evaluation of RF power degradation in microwave photonic systems employing uniform period fibre Bragg gratings

The frequency dependent radio frequency power degradation in direct modulated microwave photonic systems employing uniform period fiber Bragg gratings (FBG) as reflective elements in investigated. Results show implications in terms of the available radio frequency bandwidth and the stability requirements for the FBG

Variabilidade na coordenação motora: uma abordagem centrada no delineamento gemelar

O propósito deste estudo foi estimar a contribuição dos fatores genéticos e ambientais na variabilidade do desempenho interindividual na coordenação motora. A amostra foi constituída por 64 pares de gêmeos portugueses, com idades entre cinco e 14 anos. Avaliou-se o desempenho da coordenação através das quatro provas da bateria KTK: equilíbrio à retaguarda (ER); saltos monopedais (SM); transposição lateral (TL); saltos laterais (SL). Calculou-se o coeficiente de correlação intraclasse (t), sendo estimada a contribuição dos fatores genéticos (a²), ambientais comuns (c²) e únicos (e²). Os resultados mostram valores de t mais elevados entre gêmeos monozigóticos, sugerindo presença de fatores genéticos. Entretanto, estimativas de a² foram baixas, variando entre 15% (TL) e 41% (SM), enquanto para c² situaram-se entre 46% (SL) e 58% (TL), e para e² entre 11% (SM) e 28% (TL). Conclui-se que fatores ambientais são responsáveis pela maior parcela de influência na variabilidade do desempenho na coordenação motora.El objetivo del presente estudio fue estimar la contribución de los factores genéticos y ambientales en la vEl objetivo del presente estudio fue estimar la contribución de los factores genéticos y ambientales en la variabilidad del desempeño interindividual en la coordinación motora. La muestra fue constituida por 64 pares de gemelos portugueses, con edades entre 5 y 14 años. Se evaluó el desempeño de la coordinación a través de las cuatro pruebas de la batería KTK: equilibrio a la retaguardia (ER); saltos monopedales (SM); transposición lateral (TL); saltos laterales (SL). Se calculó el coeficiente intraclase (t), siendo estimada la contribución de los factores genéticos (a²), ambientales comunes (c²) y únicos (e²). Los resultados muestran valores t mas elevados entre gemelos monocigóticos, sugiriendo la presencia de factores genéticos. Por otro lado, estimaciones de a² fueron bajas, variando entre 15% (TL) y 41% (SM), mientras para c² se sitúan entre 46% (SL) y 58% (TL), y para e² entre 11% (SM) y 28% (TL). Se concluye que factores ambientales son responsables por la mayor porción de influencia de la variabilidad del desempeño en la coordinación motora.The purpose of this study was to estimate the contribution of environmental and genetic factors on the variability of interindividual performance in motor coordination. Sample comprised 64 twin pairs, aged 5 to 14 years old, from Portugal. Motor coordination was evaluated by KTK battery: backward balance (ER); hopping on one leg (SM); shifting platforms (TL); jumping sideways (SL). Intraclass correlation coefficient (t) was calculated. Contributions of genetic (a²), shared (c²) and unique environmental (e²) factors were estimated. Our results showed t values higher in monozygotic twins, suggesting the presence of genetic factors. Nevertheless, a² estimates were low, ranging from 15% (TL) to 41% (SM), while to common environment (c²) ranged from 46% (SL) to 58% (TL), and unique effects ranged from 11% (SM) to 28% (TL). These results suggest that environmental factors are responsible for the greatest part of influence on variability of interindividual performance in motor coordination tests

Passively mode locked c.w. dye lasers operating from 490 nm to 800 nm

Passively mode locked c.w. dyes lasers now represent an important source of femtosecond optical pulses tunable through the visible and near infra red spectrum. Pulses as short as 70 fs have been obtained from dispersion-optimised CPM cavity configurations using active/passive dyes other than the standard combination of Rhodamine 6G and DODCI.Les lasers à colorant continu à blocage de mode passif représentent actuellement une importante source d'impulsions optiques femtosecondes accordables dans le spectre visible et proche-infrarouge. Des impulsions aussi courtes que 70 fs ont été obtenues, avec des configurations de cavités à collisions d'impulsions à dispersion optimisée, par l'utilisation de colorants actifs/passifs autres que la combinaison standard Rhodamine 6G et DODCI

The generation and propagation of quasi-continuous trains of dark soliton-like pulses in 2 km of optical fiber

info:eu-repo/semantics/publishe