Optical Phase-Modulation Techniques

Optical phase-modulation technique is a very powerful tool used in a wide variety of high performance photonic systems. Fiber-optic sensors and gyroscopes, integrated-optics sensors, or high-performance photonic integrated circuits are some examples of photonic systems where the optical phase-modulation technique can be efficiently applied. In time, such a photonic system can be integrated as the core part of some specific applications like biosensors, 5G advanced optical communication devices, gyroscopes, or high-performance computation devices. In this work, the main optical phase-modulation techniques are analyzed. Also, a study of the most significant applications of this technique is made, relating it to the most appropriate type in each case

Fiber-Optic Ring Resonator Interferometer

In this chapter, theoretical analysis and electro-optical characterization of a fiber optic passive ring resonator interferometer (FOPRRI) were realized. First, a theoretical description and analysis of all-pass and add-drop filter configurations were performed, hence obtaining their respective transfer function, taking into account, the physical properties of a standard single-mode optical fiber as resonator constitutive material. Second, computational numerical simulations of a typical FOPRRI were performed with different analysis methods: effective index method (EIM), coupled mode theory (CMT), finite element method (FEM) and finite difference time domain (FDTD). Third, a comparative analysis of the results obtained with these methods is realized, showing the most accurate and appropriate for filter electro-optical characterization as a consequence. Last, and as an ultimate step, taking as reference the previously obtained electro-optical characterization for both configurations, the main applications are derived

IFOG and IORG Gyros: A Study of Comparative Performance

In this revision work, firstly classical structure and main performance parameters of interferometric fiber-optic gyroscope (IFOG) and integrated optics passive resonator gyroscope (IORG) are reviewed. Then, the main advanced models and performance parameters of these two types of rotation-rate inertial sensors are described, and finally the design trends of both types are analyzed. Taking as reference the performance parameters analyzed above, a comparative analysis between manufactured IFOG and IORG units of close geometrical dimensions is realized. This analysis leads ranking these devices into six classical levels of inertial performance: strategic grade, navigation grade, high-end tactical grade, tactical grade, industrial low-end tactical grade, and consumer grade. This classification allows to deduce the main application areas of both kinds of devices. This way, the impact of these sensors in applications such as aeronautics, aerospace navigation, mechanical micro-fabrication, tactical weapons, or, more recently, robotics can be disclosed

Optoelectronic Design of a Closed-Loop Depolarized IFOG with Sinusoidal Phase Modulation for Intermediate Grade Applications

A depolarized fiber optic gyroscope (DFOG) prototype with closed-loop configuration, sinusoidal-bias, and serrodyne-feedback electrooptic phase modulations was designed. A complete optoelectronic design is realized by using computational simulation tools (optical subsystem: Synopsys®-Optsim™ software and electronic subsystem: National Instruments®-MultiSim™ software). The design presented here includes both optical and electronic circuits, being the main innovation, is the use of an analogical integrator provided with reset and placed in the feedback of the electrooptic phase-modulation chain that produces a serrodyne-shaped voltage ramp signal for obtaining the interferometric signal phase cancellation. The performance obtained for this model (threshold sensitivity ≤0.052°/h; dynamic range = ± 78.19°/s) does reach the IFOG intermediate grade (tactical and industrial applications) and does demonstrate the suitability and reliability of simulation-based software tools for this kind of optoelectronic design

Modelización de la probabilidad de ocurrencia de incendios forestales por rayo en la provincia de León (NO de España)

Spatial relationships between lightning-induced forest fires and topography, vegetation, climate and lightning characteristics were analyzed in the province of León (NW Spain). The study was based on reported lightning-induced forest fires in the period 2002-2007. A statistical model based on logistic regression was developed to estimate the probability of occurrence of a lightning-induced fire in a 3 x 3 km grid. The importance of accurate location of the ignition point was also investigated in order to evaluate the sensitivity of the model developed to uncertainty of the location. The model developed with accurate ignition point data showed a better predictive ability than the model constructed with all the ignition points available. The former model was therefore selected for long-term prediction of the occurrence of lightning-induced fires in the province. According to this model, the probability of a forest stand being affected by lightning-induced fire increased with decreasing altitude, and when there was a high proportion of coniferous species in the stand, a high percentage of lightning strikes in forest areas and a high number of dry storm days in the area. Although the model has not been validated, the results can be considered spatially robust because it shows good classification ability and the predicted spatial probability distribution is consistent with the observed historical fire records. The model will be useful in the spatially explicit assessment of fire risk, the planning and coordination of regional efforts to identify areas at greatest risk, and in designing long-term wildfire management strategies.En este estudio se analizaron las relaciones espaciales entre incendios forestales originados por rayo y variables topográficas, de vegetación, de clima y de las características de las descargas de rayos en la provincia de León (NO de España). Se utilizaron datos de incendios forestales originados por rayo en la provincia en el período 2002-2007. La probabilidad de ocurrencia de incendio se estimó para una malla de 3 km x 3 km de lado mediante un modelo logístico. Se analizó también la importancia que posee una localización exacta del punto de inicio del incendio en los resultados del modelo desarrollado y la sensibilidad del mismo a la incertidumbre de la localización. El modelo desarrollado a partir de todos los puntos de inicio de incendio disponibles en la base de datos mostró una peor capacidad predictiva que el desarrollado a partir de datos exactos del punto de inicio. Este último fue, por tanto, el seleccionado para realizar la predicción a largo plazo de los incendios provocados por rayo en la provincia. De acuerdo con este modelo, la probabilidad de ocurrencia de un incendio causado por rayo aumenta según disminuye la altitud, cuando existe una elevada proporción de coníferas, un elevado porcentaje de descargas de rayos en terreno forestal y un elevado número de días de tormentas secas.Aunque el modelo no ha sido validado, los resultados del mismo pueden considerarse espacialmente robustos ya que el modelo tiene una buena capacidad de clasificación y la distribución espacial predicha es consistente con los registros históricos de incendios. El modelo obtenido es útil en la valoración explícita del riesgo de incendios, en la identificación de zonas de riesgo elevado, así como en el diseño de estrategias para la gestión de incendios forestales a largo plazo

Modelling the probability of lightning-induced forest fire occurrence in the province of León (NW Spain)

P. 95 -107En este estudio se analizaron las relaciones espaciales entre incendios forestales originados por rayo y variables topográficas, de vegetación, de clima y de las características de las descargas de rayos en la provincia de León (NO de España). Se utilizaron datos de incendios forestales originados por rayo en la provincia en el período 2002-2007. La probabilidad de ocurrencia de incendio se estimó para una malla de 3 km × 3 km de lado mediante un modelo logístico. Se analizó también la importancia que posee una localización exacta del punto de inicio del incendio en los resultados del modelo desarrollado y la sensibilidad del mismo a la incertidumbre de la localización. El modelo desarrollado a partir de todos los puntos de inicio de incendio disponibles en la base de datos mostró una peor capacidad predictiva que el desarrollado a partir de datos exactos del punto de inicio. Este último fue, por tanto, el seleccionado para realizar la predicción a largo plazo de los incendios provocados por rayo en la provincia. De acuerdo con este modelo, la probabilidad de ocurrencia de un incendio causado por rayo aumenta según disminuye la altitud, cuando existe una elevada proporción de coníferas, un elevado porcentaje de descargas de rayos en terreno forestal y un elevado número de días de tormentas secas. Aunque el modelo no ha sido validado, los resultados del mismo pueden considerarse espacialmente robustos ya que el modelo tiene una buena capacidad de clasificación y la distribución espacial predicha es consistente con los registros históricos de incendios. El modelo obtenido es útil en la valoración explícita del riesgo de incendios, en la identificación de zonas de riesgo elevado, así como en el diseño de estrategias para la gestión de incendios forestales a largo plazoS

Modelización de la probabilidad espacial de ocurrencia de incendios forestales por rayo en la provincia de León.

Los incendios forestales son el principal agente perturbador y destructor del medio natural en la provincia de León. De ellos los originados por rayos, pese a representar globalmente un porcentaje relativamente bajo con recpecto al total de los que se producen en la provincia, en determinados años suponen más de un 20 % de la superficie total quemada. En este trabajo se elaboró un modelo que permite estimar la probabilidad espacial de ocurrencia de incendios forestales por rayo en la provincia de León. La función utilizada para modelizar dicha probabilidad fue la función logística, considerando como variable dependiente la presencia /ausencia de al menos un incendio causado por rayo en una cuadrícula de 9 km2 en el periodo 2002-200

Does Extended Interval Dosing Natalizumab Preserve Effectiveness in Multiple Sclerosis? A 7 Year-Retrospective Observational Study

The extended interval dosing (EID) of natalizumab has been suggested to be associated with a reduced risk of progressive multifocal leukoencephalopathy (PML) and short-term preservation of efficacy but its long-term effectiveness remain unknown. We aimed to determine the long-term effectiveness and safety of natalizumab in an EID setting in a cohort of patients with multiple sclerosis (MS) treated for more than 7 years. We conducted an observational retrospective cohort study, including 39 (34 female, 5 male) patients with clinically definite relapsing-MS, initially treated with standard interval dosing (SID) of natalizumab (mean time 54 months [SD29]) who were then switched to EID, every 8 weeks (mean time 76 months [SD13]). The main outcome measures included the following: i) annualized relapse rate (ARR), ii) radiological activity, iii) disability progression, and iv) NEDA-3 no evidence of disease activity index. EID preserved ARR, radiological activity, and prevented disability worsening during follow-up. The proportion of patients maintaining their NEDA-3 status after 24, 48, and 72 months of natalizumab administration in EID was 94%, 73%, and 70%, respectively. Stratified analysis according to history of drug therapy showed that the EID of natalizumab was slightly more effective in naïve patients than in those previously treated with other immunosuppressive drugs. No cases of PML or other severe adverse reactions were reported. In conclusion, long-term therapy with natalizumab in an EID setting following an SID regimen maintained its disease-modifying activity, and was safe and well tolerated for over 7 years. These encouraging observational results need to be confirmed in controlled clinical trials.FUNDING: This study was supported by IDIVAL (NVAL 16/11)

Mapas de actividades comunitarias y activos para la salud: ¿Cómo trabajar con ellos?

El modelo de activos para la salud tiene relaciones íntimas con el paradigma de la Promoción de la Salud, de modelos de Desarrollo Comunitario o de la Teoría Salutogénica de Antonovsky, siendo su punto de partida la Salud Positiva de una comunidad y de las personas que la integran

Os nacionalismos ibéricos nos estudos sobre o romanceiro tradicional

1 As bases do problema. – 2 Contornos do(s) nacionalismo(s) ibérico(s). – 2.1 O caso português. – 2.2 O caso catalão. – 2.3 O caso galego. – 3 O comparatismo como metodologia. – 4 Que pan-hispanismo? Alguns equívocos e desconhecimentos. – 4.1 Fontes documentais e estudos críticos. – 4.2 Na atividade editorial. – 5 Palavras finaisinfo:eu-repo/semantics/publishedVersio