Webinar: Búsqueda bibliográfica en la plataforma E Libro

En este webinar de nuestra Biblioteca, aprenderás a realizar búsquedas bibliográficas en la plataforma E Libro.Fil: Universidad Católica de Córdoba, Argentina.Fil: Universidad Católica de Córdoba, Argentina

A differential geometry approach to asymmetric transmission of light

In the last ten years, the technology of differential geometry, ubiquitous in gravitational physics, has found its place in the field of optics. It has been successfully used in the design of optical metamaterials, through a technique now known as "transformation optics". This method, however, only applies for the particular class of metamaterials known as impedance matched, that is, materials whose electric permittivity is equal to their magnetic permeability. In that case, the material may be described by a spacetime metric. In the present work we will introduce a generalization of the geometric methods of transformation optics to situations in which the material is not impedance matched. In such situation, the material -or more precisely, its constitutive tensor- will not be described by a metric only. We bring in a second tensor, with the local symmetries of the Weyl tensor, the "$W$-tensor". In the geometric optics approximation we show how the properties of the $W$-tensor are related to the asymmetric transmission of the material. We apply this feature into the design of a particularly interesting set of asymmetric materials. These materials are birefringent when light rays approach the material in a given direction, but behave just like vacuum when the rays have the opposite direction with the appropriate polarization (or, in some cases, independently of the polarization)

Influence of Portfolio Management in Decision-Making

Purpose: Today’s manufacturing facilities are challenged by highly customized products and just in time manufacturing and delivery of these products. In this study, a batch scheduling problem has been addressed to enable on-time completion of customer orders in a lean manufacturing environment. The problem is optimizing the partitioning of product components into batches and scheduling of the resulting batches where each customer order is received as a set of products made of various components. Design/methodology/approach: Three different mathematical models for minimization of total earliness and tardiness of customer orders are developed to provide on-time completion of customer orders and also, to avoid excess final product inventory. The first model is a non-linear integer programming model whereas the second is a linearized version of the first. Finally, to solve larger sized instances of the problem, an alternative linear integer model is presented. Findings: Computational study using a suit set of test instances showed that the alternative linear integer model is able to solve all test instances in varying sizes within quite shorter computer times compared to the other two models. It has also been showed that the alternative model is able to solve moderate sized real-world problems. Originality/value: The problem under study differentiates from existing batch scheduling problems in the literature owing to the inclusion of new circumstances that are present in real-world applications. Those are: customer orders consisting of multi-products made of multi-parts, processing of all parts of the same product from different orders in the same batch, and delivering the orders only when all related products are completed. This research also contributes to the literature of batch scheduling problem by presenting new optimization models.Peer Reviewe

El Índice Wally: una propuesta altmétrica para las editoriales cubanas indexadas en la plataforma e-Libro.com

Objective.It was proposed an altmetric index to identify the most consulted titles of Cuban publishers that distribute their contents on the e-Libro. comacademic platform. Design/Methodology/Approach.The Wally Index is defined as the quotient of the Ln (# queries) of a title between the maximum Ln (# queries) of the set of titles evaluated in a defined period of time. The usefulness of this Index was validated from the study of the distribution of titles of six Cuban publishers that include their titles in the academic platform e-Libro.com,during the period September 2016 - August 2017. Results/Discussion.The Wally Index vs.# Titles of Cuban publishers available on e-libro.comwere adjusted to the power model, with a Pearson correlation coefficient of R 2 = 0.7299, although titles with smaller numbers of queries showed greater dispersion, so that evaluated this index with the collection of the 226 most consulted titles. With this sample, the Wally Index normalized vs.ranking of the titles reached the value of the Pearson correlation coefficients R 2 = 0.8992 with a logarithmic adjustment. Conclusions.The use of the Wally Index is proposed for the evaluation of the queries of a set of titles, selected under specific criteria, available on Web platforms that provide data on the queries. The index is relative to the collection of titles and is independent of the number of queries. Originality/Value.The Wally Index can be used by any publisher who wants to examine the queries that receive their titles in the web environment

St. Isidore of Seville A Paradigm for the Christian Teaching

Este ensayo presenta el papel que desempeñó San Isidoro en su contexto histórico y de qué manera su pensamiento se constituye un aporte imprescindible para la actualidad, rescatándose así su aporte a la civilización occidental. Se puede decir que por su gran erudición Isidoro es un paradigma para todos los docentes cristianos debido a su incansable búsqueda de la verdad, como recopilador, filósofo y orador unidos a su gran labor pastoral, todo fundamentado en la contemplación

Propuesta de control y monitoreo desde una central de personal de obra, para un proyecto de construcción basado en un estudio de caso

Trabajo de InvestigaciónEste trabajo tiene como fin el crear una propuesta de carácter investigativo pretendiendo plantear el funcionamiento desde la parte administrativa centralizada en proyectos de ingeniería y arquitectura, enfocándose en la eficiencia de los procesos de administración, control y monitoreo de una Obra.INTRODUCCIÓN 1. GENERALIDADES 2. MARCOS DE REFERENCIA 3. METODOLOGÍA 4. CONCLUSIONES BIBLIOGRAFÍA ANEXOSEspecializaciónEspecialista en Gerencia de Obras Civile

Guía práctica para el uso de e-Books

Si desea acceder a la Biblioteca Virtual desde la red UNAB, ya sea por medio de un PC de Laboratorio o personal, o un dispositivo portátil conectado a Wi-fi, no se necesita clave de acceso. Para acceder a los recursos electrónicos fuera de la red UNAB debe estar registrado como usuario en el Sistema de Bibliotecas. Luego ingrese al sitio web de biblioteca http://biblioteca.unab. cl y complete los datos solicitados

A fluctuating ascendency: The "Spanish Party" at the Imperial Court Of Vienna (1631-1659)

With the arrival in 1631 of Emperor Ferdinand III’s bride to Vienna, the infanta Maria Anna, the “Spanish party” at the Imperial court gained a remarkable momentum. At the time, Philip IV’s interests found a key ally in the person of his sister, who, along with her influential confessor Diego de Quiroga, exerted an indisputable influence over the direction of Imperial issues for the following decades. Nevertheless, the empress’s untimely death, as well as the consequential return of Quiroga to the Peninsula, seriously undermined Spain’s interests and had a negative impact on the outcome of the Peace of Westphalia. In addition, the situation was further exacerbated by a sharp drop in the means to fund a long list of pensioners and collaborators of the Spanish Crown. With a weakened party lacking leadership, the Spanish ambassador, within his recovered prominence, promoted the rise of a new figure as guarantor of Madrid’s interests: the count of Auersperg, a powerful minister which would hold a leading position in Ferdinand III’s government. Madrid, however, risked a great deal by focusing his support on a too ambitious a candidate with plenty of enemies. The rupture in 1656 between Auersperg and the Catholic ambassador implied a serious jeopardy for the Madrid’s position, in a very sensitive period regarding the survival of the Spanish MonarchyLa llegada en 1631 a Viena de la esposa de Fernando III, la infanta María, propició que el “partido español” en la Corte imperial cobrara un inusitado impulso respecto a épocas anteriores. Los intereses de Felipe IV hallaron por entonces un inmejorable aliado en su hermana, la cual, junto a su influyente confesor, Diego de Quiroga, ejerció un indiscutible ascendiente en la dirección de los asuntos imperiales durante los siguientes decenios. Sin embargo, la prematura defunción de la emperatriz y el consecuente regreso de Quiroga a la Península minaron seriamente las conveniencias de España y ello se dejó sentir de manera aguda en el desenlace de los tratados de Westfalia. A ello se añadió una abrupta reducción de los medios para costear una larga lista de pensionados y colaboradores de la Corona española. Con un partido debilitado y sin liderazgo, el embajador español, dentro de su renovado protagonismo, fomentará el ascenso de una nueva figura como garante de los intereses de Madrid: el conde de Auersperg, un poderoso ministro que pasaría a ocupar una posición preeminente en el gobierno de Fernando III. No obstante, Madrid arriesgó mucho al centrar su apoyo en un candidato demasiado ambicioso y rodeado de enemigos, ya que la ruptura en 1656 entre Auersperg y el embajador católico comportó un serio riesgo para la posición española en un momento extremamente delicado para la supervivencia de la Monarquía Hispánica