Rapidly convergent quasi-periodic Green functions for scattering by arrays of cylinders---including Wood anomalies

This paper presents a full-spectrum Green function methodology (which is valid, in particular, at and around Wood-anomaly frequencies) for evaluation of scattering by periodic arrays of cylinders of arbitrary cross section-with application to wire gratings, particle arrays and reflectarrays and, indeed, general arrays of conducting or dielectric bounded obstacles under both TE and TM polarized illumination. The proposed method, which, for definiteness is demonstrated here for arrays of perfectly conducting particles under TE polarization, is based on use of the shifted Green-function method introduced in the recent contribution (Bruno and Delourme, Jour. Computat. Phys. pp. 262--290 (2014)). A certain infinite term arises at Wood anomalies for the cylinder-array problems considered here that is not present in the previous rough-surface case. As shown in this paper, these infinite terms can be treated via an application of ideas related to the Woodbury-Sherman-Morrison formulae. The resulting approach, which is applicable to general arrays of obstacles even at and around Wood-anomaly frequencies, exhibits fast convergence and high accuracies. For example, a few hundreds of milliseconds suffice for the proposed approach to evaluate solutions throughout the resonance region (wavelengths comparable to the period and cylinder sizes) with full single-precision accuracy

On the evaluation of quasi-periodic Green functions and wave-scattering at and around Rayleigh-Wood anomalies

This article presents full-spectrum, well-conditioned, Green-function methodologies for evaluation of scattering by general periodic structures, which remains applicable on a set of challenging singular configurations, usually called Rayleigh-Wood (RW) anomalies (at which the quasi-periodic Green function ceases to exist), where most existing quasi-periodic solvers break down. After reviewing a variety of existing fast-converging numerical procedures commonly used to compute the classical quasi-periodic Green-function, the present work explores the difficulties they present around RW-anomalies and introduces the concept of hybrid “spatial/spectral” representations. Such expressions allow both the modification of existing methods to obtain convergence at RW-anomalies as well as the application of a slight generalization of the Woodbury-Sherman-Morrison formulae together with a limiting procedure to bypass the singularities. (Although, for definiteness, the overall approach is applied to the scalar (acoustic) wave-scattering problem in the frequency domain, the approach can be extended in a straightforward manner to the harmonic Maxwell's and elasticity equations.) Ultimately, this thorough study of RW-anomalies yields fast and highly-accurate solvers, which are demonstrated with a variety of simulations of wave-scattering phenomena by arrays of particles, crossed impenetrable and penetrable diffraction gratings and other related structures. In particular, the methods developed in this article can be used to “upgrade” classical approaches, resulting in algorithms that are applicable throughout the spectrum, and it provides new methods for cases where previous approaches are either costly or fail altogether. In particular, it is suggested that the proposed shifted Green function approach may provide the only viable alternative for treatment of three-dimensional high-frequency configurations with either one or two directions of periodicity. A variety of computational examples are presented which demonstrate the flexibility of the overall approach

Scenes From Tick Physiology: Proteins of Sialome Talk About Their Biological Processes

Ticks are blood-sucking parasites with different strategies of feeding depending on the tick family. The major families are Ixodidae or Argasidae, being slow or fast feeders, respectively. In the recent years, the advances in molecular sequencing techniques have enabled to gain knowledge about the proteome of the tick''s salivary glands. But an holistic view of the biological processes underlying the expression of the sialome has been neglected. In this study we propose the use of standard biological processes as a tool to draw the physiology of the tick''s salivary glands. We used published data on the sialome of Rhipicephalus sanguineus s.l. (Ixodidae) and Ornithodoros rostratus (Argasidae). A partial set of proteins obtained by these studies were used to define the biological process(es) in which proteins are involved. We used a directed network construction in which the nodes are proteins (source) and biological processes (target), separately for the low-level processes ("children") and the top-level ones ("parents"). We applied the method to feeding R. sanguineus at different time slices, and to different organs of O. rostratus. The network connects the proteins and the processes with a strength directly proportional to the transcript per millions of each protein. We used PageRank as a measure of the importance of each biological process. As suggested in previous studies, the sialome of unfed R. sanguineus express about 30% less biological processes than feeding ticks. Another decrease (25%) is noticed at the middle of the feeding and before detachment. However, top-level processes are deeply affected only at the onset of feeding, demonstrating a redundancy in the feeding. When ixodid-argasid are compared, large differences were observed: they do not share 91% of proteins, but share 90% of the biological processes. However, caution must be observed when examining these results. The hypothesis of different proteins linked to similar biological process(es) in both ticks is an extreme not confirmed in this study. Considering the limitations of this study, carried out with a selected set of proteins, we propose the networks of proteins of sialome linked to their biological processes as a tool aimed to explain the biological processes behind families of proteins

Incentives and inhibiting factors of eco-innovation in the Spanish firms.

This paper investigates the incentives and inhibiting factors of eco-innovation capacities in the firm. Firms materialize the objectives of eco-innovation from a reactive attitude to external pressures, to a more proactive attitude that implies the voluntary incorporation of eco-innovation activities. This variability in the behaviour of companies with respect to the level of eco-innovation development has been a motivator for the research. However, despite the importance of this research question, this has been approached in a dispersed way from multiple approaches. From a dynamic capabilities perspective, we assume that the innovation capacity of the firm encourages eco-innovations. Our paper is focused on the process of eco-innovation, identifying the elements that facilitate or hinder the eco-innovation in the firm. We study the Spanish case, using a panel from the Spanish Innovation Survey, with a sample of 5,461 Spanish firms. The results highlight that the complexity of the eco-innovation process negatively affects the decision to develop eco-innovations. However, our results suggest that institutions and organizations of the Spanish environment are making efforts to compensate these obstacles and provide incentives to develop eco-innovations

El derecho a la igualdad de los justiciables en los procesos de declaración paternos-filiales para una efectiva tutela jurisdiccional

Los procesos de filiación, a pesar de ser los más recurrentes en el Juzgado de Paz Letrado de Lambayeque, tienen casi nula oposición; dicho de otra forma, el aparato judicial, “por la fuerza de la Ley”, establece el vínculo paterno-filial, por lo que los emplazados se ven forzados a aceptar una paternidad incierta, ya que el oponerse implicaría costear el examen de ADN. Por otro lado, la publicación de la Ley 30628, no abona cambios importantes que coadyuven una efectiva tutela jurisdiccional por la parte perjudicada. En este contexto, se tendrá como objetivo general, analizar si prevalece el derecho a la igualdad entre los justiciables, en aquellos procesos de declaración paterno-filiales, según la ley N° 28457, la cual ha sufrido una modificatoria a través de la reciente ley N° 30628, siendo así, que se detallará la incidencia de esta problemática los años 2015 – 2016, con su modificatoria de la Ley 30628, teniendo como base la revisión de casos con sentencia firme emitidas por el Juzgado de Paz Letrado de Lambayeque. Finalmente, como Hipótesis se propone, la modificación de la norma 28457, específicamente en su artículo 2, respecto “(...)El costo de la prueba es abonado por la parte demandada en la audiencia al laboratorio privado al que se encargue la realización de la prueba(...)1 ”, que el 100 % del costo, lo asuman los justiciables en partes iguales, y se exonere el pago en personas de escasos recursos económicos, con tal propuesta se verificará si puede constituir la solución a esta problemática que en nuestra localidad se ve a diario, puesto que se constituye como una norma que ha recortado una serie de derechos, eliminando todo debate contradictorio, ciñendo la defensa del emplazado a la oposición

Propuesta de Estrategias para el Análisis Semiótico del Texto Narrativo en Undécimo Grado de Educación Media.

Este trabajo presenta una Propuesta de Estrategias para el Análisis Semiótico del Texto Narrativo en Undécimo Grado de Educación Media. Esta propuesta aunque dirigida al grado undécimo, puede extenderse a niveles inferiores de acuerdo con la adecuación que de ella hagan los profesores encargados de su aplicación. Comprende esta parte del trabajo los siguientes aspectos: planteamiento del problema, justificación, objetivos, marco teórico y diseño metodológico. El diseño curricular del área de Español y Literatura de la educación media, a pesar de la reforma curricular, continúa presentando en gran medida un enfoque que se apoya en la teoría saussureana sobre lenguaje-lengua habla, la cual no da la suficiente importancia a la interacción social en el proceso de la comunicación pues considera el lenguaje y la lengua en particular como instrumentos heredados y acabados de los cuales nos valemos pero a los que los factores contextuales no modifican; y, reduce a simples habilidades el complejo proceso de la comunicación, olvidando que la lengua y el lenguaje en general son una estructura dinámica que incorpora diversos elementos sígnicos y códigos semióticos. En cuanto a la enseñanza de la literatura, se hace énfasis en la teorización, el biografismo y el historicismo literario y, el análisis que se hace de la obra narrativa se reduce a analizar los elementos del "Fondo" y de la "Forma". Pero no contempla el currículo, ni incluyen los profesores, un análisis semiótico, es decir, un estudio de los elementos 'sígnicos tanto lingüísticos como no lingüísticos, los cuales contribuyen a dar mayor significación a la obra literaria, pues la literatura es un proceso de semiosis dado por la totalidad de los signos. Se hace necesario, entonces, implementar y proponer a los docentes que a diario enfrentan el manejo de la lengua y la literatura estrategias metodológicas con el propósito de que inicien a sus alumnos en el Análisis Semiótica del Texto Narrativo, el cual comprende los siguientes elementos: iconos, símbolos, signos paralingüísticos, códigos socioculturales compuestos por códigos proxémicas, icónicos o imágenes sociales, símbolos sociales, rituales, míticos, protocolarios, supersticiones y sueños, códigos de honor; además, otros signos como los de identidad, del vestuario y de cortesía e índices olfativo

Wave-Scattering by Periodic Media

This thesis presents a full-spectrum, well-conditioned, Green-function methodology for evaluation of scattering by general periodic structures, which remains applicable on a set of challenging singular configurations, usually called Rayleigh-Wood (RW) anomalies, where most existing methods break down. After reviewing a variety of existing fast-converging numerical procedures commonly used to compute the classical quasi-periodic Green-function, the present work explores the difficulties they present around RW-anomalies and introduces the concept of hybrid "spatial/spectral" representations. Such expressions allow both the modification of existing methods to obtain convergence at RW-anomalies as well as the application of a slight generalization of the Woodbury-Sherman-Morrison formulae together with a limiting procedure to bypass the singularities. Although, for definiteness, the overall approach is applied to the scalar (acoustic) wave-scattering problem in the frequency domain, the approach can be extended in a straightforward manner to the harmonic Maxwell's and elasticity equations. Ultimately, the thorough understanding of RW-anomalies this thesis provides yields fast and highly-accurate solvers, which are demonstrated with a variety of simulations of wave-scattering phenomena by arrays of particles, crossed impenetrable and penetrable diffraction gratings, and other related structures. In particular, the methods developed in this thesis can be used to "upgrade" classical approaches, resulting in algorithms that are applicable throughout the spectrum, and it provides new methods for cases where previous approaches are either costly or fail altogether. In particular, it is suggested that the proposed shifted Green function approach may provide the only viable alternative for treatment of three-dimensional high-frequency configurations. A variety of computational examples are presented which demonstrate the flexibility of the overall approach, including, in particular, a problem of diffraction by a double-helix structure, for which numerical simulations did not previously exist, and for which the scattering pattern presented in this thesis closely resembles those obtained in crystallography experiments for DNA molecules.</p