Comment on “Application of Fresnel diffraction to nondestructive measurement of the refractive index of optical fibers”

We examine the validity of Eq. (5) in [A. Sabatyan and M. T. Tavassoly, “Application of Fresnel diffraction to nondestructive measurement of the refractive index of optical fibers,” Opt. Eng., 2007, Vol. 46(12), pp. 128001-1–128001-7] to describe the diffraction pattern of an optical fiber. We show that Eq. (5) must be changed to account for the phase introduced by the fiber correctly. In particular, we show that, to agree with the implicit criterion for representing traveling waves, given when using the Fresnel–Kirchoff integral [Eq. (4)], the phase introduced by the object must be carried by positive exponentials. The results obtained correcting Eq. (5) are compared with those obtained by the rigorous solution of Maxwell equations in the optical fiber. We demonstrate the importance of adequately taking into account the criterion implicitly assumed in the Fresnel–Kirchoff integral to represent traveling waves.This work was supported by the “Ministerio de Economía Industria y Competitividad” (Spain) under Project No. FIS2017-82919-R (MINECO/AEI/FEDER, UE)

The Dilemma of Genocide in the Old Testament

The Old Testament command to destroy every breathing thing within the cities of the Promised Land has long been a problem for those who seek to understand God. In some cases this has become welcome fodder for those who desire to question the credibility of Scripture, while for others it just creates an ethical gap that is simply too far to cross. This thesis will address the challenging issue by demonstrating how God\u27s command to destroy the Canaanites was an essential component of his redemptive plan in that it brought to fruition the goals of the Abrahamic Covenant and established a line to Christ who would become the ultimate redeemer of the world

Silver halide sensitized gelatin derived from BB-640 holographic emulsion

Silver halide sensitized gelatin (SHSG) is one of the most interesting techniques for the production of holographic optical elements, achieving relatively high sensitivity of photographic material with a low scattering of dichromated gelatin. Here we present experimental results for SHSG derived from the novel BB-640, a red-sensitive ultra-fine-grain emulsion from Holographic Recording Technologies (Steinau, Germany). The material is characterized before recording and after processing, and information about the thickness, absorption, and refractive-index modulation of the final holograms is obtained. The influence of the developer is analyzed, and diffraction efficiencies as great as 96.2% (after allowing for reflections) with a transmission of 1% and absorption and scatter losses of 2.8% are obtained with AAC developer. Our investigations reveal that high-quality SHSG transmission holograms may be obtained with the new BB-640 plates.This study was supported by the Comisión Interministerial de Ciencia y Tecnología of Spain under project MAT97-0705-C02-02

Elasticidad por flexión: una experiencia de laboratorio adaptable a los distintos niveles educativos

El estudio de distintos aspectos del comportamiento mecánico de los materiales se lleva a cabo en asignaturas como Física, Mecánica, Ciencia de los Materiales o Resistencia de Materiales en distintos niveles educativos, tanto en el bachillerato como en la universidad. En este trabajo se presenta una experiencia de laboratorio que puede llevarse a cabo utilizando un material muy simple y de bajo coste, que permite estudiar -mediante medidas muy sencillas, básicamente longitudes y masas- la flexión de una barra empotrada en un extremo sometida a una carga distribuida (su propio peso) y a una carga puntual vertical aplicada en el extremo libre. El comportamiento de la barra frente a la flexión depende de sus propiedades geométricas y del módulo de Young del material. Lo importante de esta experiencia es que, aún siendo la misma en todos los niveles educativos, es posible aumentar su grado de complejidad dependiendo del nivel de que se trate

Propiedades psicométricas de la versión española de la Escala de Factores Protectores de la Resiliencia

Background/Objective: The purpose of the present study was to adapt the Protective Factors of Resilience Scale (PFRS) to Spanish and to analyze its psychometric properties. Method: The scale was translated and adapted into Spanish, then, two studies were carried out to examine its psychometric properties in two samples (healthy and chronic illness). Questionnaires were sent by email, Facebook, and Whatsapp, and 442 adults completed all the questionnaires. The entire sample included 352 healthy people and 90 with a chronic illness. Results: In both samples, confirmatory factor analyses confirmed the scale’s structure, yielding a Spanish version of PFRS with three factors. The PFRS total and subscales scores showed adequate reliability. Concurrent validity was also confirmed; the PFRS was positively correlated with different measures. Conclusions: Therefore, the Spanish version of this scale is a reliable and valid instrument to assess protective factors (internal and external resources) of resilience both in Spanish general and chronically ill populations.Antecedentes/Objetivo: El objetivo del estudio fue adaptar la escala Protective Factors of Resilience Scale al español y analizar sus propiedades psicométricas. La escala fue traducida y adaptada al español y posteriormente se realizaron dos estudios para analizar sus propiedades psicométricas en dos muestras (personas sanas y con enfermedades crónicas). Método: Los cuestionarios se enviaron por diferentes vías: email, Facebook y Whatsapp, 442 adultos completaron todos los cuestionarios. La muestra estuvo compuesta por 352 personas sanas y 90 con enfermedades crónicas. Resultados: En ambas muestras, los análisis de factores confirmatorios confirmaron la estructura de la escala, mostrando que la versión española estaba compuesta de tres factores. Las puntuaciones totales de la escala y de las subescalas mostraron una fiabilidad adecuada. La validez concurrente también se confirmó; la escala estuvo relacionada positivamente con diferentes medidas. Conclusión: Por tanto, la versión española de la escala es un instrumento fiable y válido para evaluar factores protectores (internos y externos) de la resiliencia tanto para población general como para personas con enfermedades crónicas

Accurate control of a liquid-crystal display to produce a homogenized Fourier transform for holographic memories

We show an accurate procedure to obtain a Fourier transform (FT) with no dc term using a commercial twisted-nematic liquid-crystal display. We focus on the application to holographic storage of binary data pages, where a drastic decrease of the dc term in the FT is highly desirable. Two different codification schemes are considered: binary π radians phase modulation and hybrid ternary modulation. Any deviation in the values of the amplitude and phase shift generates the appearance of a strong dc term. Experimental results confirm that the calculated configurations provide a FT with no dc term, thus showing the effectiveness of the proposal.This work was supported by the “Ministerio de Educación y Ciencia (Spain)” under projects FIS2005-05881-C02-01 and FIS2005-05881-C02-02, and by the “Generalitat Valenciana” under Project GV06/007

Creencias de control en cáncer: una revisión de la literatura

The use of the control construct is widespread in research about chronic illness. Our aim was to analyse the relationship between perceived control and health outcomes in people with cancer. A search of databases (Medline, PsycINFO and Psicodoc) for articles published between 1966 and 2006 were conducted. Key words related to cancer, control beliefs and health outcomes were combined and searched resulting in the identification of 716 studies; 44 of the articles located met the criteria for inclusion in this review. The review showed that, firstly, selfefficacy beliefs had more power over patients’ adaptation than the other belief constructs. Secondly, locus of control beliefs were the most frequently assessed beliefs in the 44 studies; however, there was a lack of association between locus of control and health outcomes. Internal locus of control was the dimension with the most positive relationship with emotional status and quality of life.El control es un constructo ampliamente utilizado en las investigaciones sobre enfermedades crónicas en general. Nuestro objetivo fue analizar la relación entre el constructo de control percibido y los resultados de salud en cáncer. Hemos revisado los estudios publicados en las bases de datos Medline, PsycINFOy Psicodoc, el periodo de tiempo que abarcó la búsqueda fue entre 1966 y 2006. En el diseño de búsqueda introdujimos las palabras cáncer, creencias de control y resultados de salud. Se encontraron 716 estudios, 44 de los cuales se incluyeron en la revisión. La revisión muestra, en primer lugar, que las creencias de autoeficacia tienen mayor poder predictivo sobre la adaptación de las pacientes que otro constructo. En segundo lugar, las creencias de locus de control fueron las que más se utilizaron. El locus de control interno fue la dimensión que mostró mayores relaciones positivas con los resultados de salud

Determination of the refractive index and thickness of holographic silver halide materials by use of polarized reflectances

A method to determine the refractive index and thickness of silver halide emulsions used in holography is presented. The emulsions are in the form of a layer of film deposited on a thick glass plate. The experimental reflectances of p-polarized light are measured as a function of the incident angles, and the values of refractive index, thickness, and extinction coefficient of the emulsion are obtained by using the theoretical equation for reflectance. As examples, five commercial holographic silver halide emulsions are analyzed. The procedure to obtain the measurements and the numerical analysis of the experimental data are simple, and agreement of the calculated reflectances, by use of the thickness and refractive index obtained, with the measured reflectances is satisfactory.This work was partially financed by the Comisión Interministerial de Ciencia y Tecnología, Spain, under project No. MAT2000-1361-C04-04 and the Oficina de Ciencia y Tecnología (Generalitat Valenciana, Spain) under project No. GV01-130

Split-field finite-difference time-domain method for second-harmonic generation in two-dimensionally periodic structures

The split-field finite-difference time-domain method is extended to second-harmonic generation in two-dimensionally periodic structures. Making use of the full coefficient-tensor formalism, a coupled nonlinear system of equations, which must be solved at each update of the electromagnetic field, is developed. The accuracy of the method is verified by comparing the results to well-known one-dimensional problems. The results for L-shaped arrays are compared with results obtained with the Fourier modal method.This work is partially supported by the “Ministerio de Economía y Competitividad” of Spain under project FIS2011-29803-C02-01; by the “Generalitat Valenciana” of Spain under projects PROMETEO/2011/021, ISIC/2012/013, and GV/2014/076; and by the “Universidad de Alicante” of Spain under project GRE12-14