Effects of random mating F2 populations of maize

Two experiments were conducted to evaluate the effects of random mating in the F(,2) of four single crosses of maize (Zea mays L.): B73 x Mo17 (unrelated parents), B73 x B84 (related parents), and B73 x B79 and B77 x Mo17 (intermediate parent relation). The objective of the first experiment was to estimate the change in means over six generations of random mating. S(,1) progenies were derived in the F(,2) and F(,2)Syn5 generations of B73 x Mo17 and B73 x B84 (second experiment) to estimate the changes in genetic variances and traits associations of 14 traits due to random mating.;Changes in means were not expected with random mating under the assumption of no epistasis. There were some small changes in the means of the four single crosses, measured by the regression coefficient for grain yield and grain moisture, that were attributed to either natural selection or epistatic effects.;There were some instances in B73 x Mo17 where the genetic variability was reduced significantly, suggesting that coupling linkage phase was predominant in those traits. The estimates of genetic variances in B73 x B84 increased significantly for some traits, which suggests that repulsion linkage phase was predominant. No significant change was observed for grain yield in the B73 x Mo17 cross. The range of variability was not increased for most traits. The changes in genetic variances suggested that recombination was enhanced and were attributed to either changes in linkage disequilibrium or changes in allelic frequency that occurred during the generations of random mating. The range of segregation was higher in the B73 x Mo17 cross.;There were some significant changes in the genetic correlation coefficients of trait associations in B73 x Mo17 and B73 x B84 single crosses; a higher proportion of changes were observed in the B73 x Mo17 cross. On the average, the genetic correlation between traits was increased significantly in 64% of trait associations. Some changes in the correlation between grain yield and some traits were observed in B73 x Mo17, but no change was observed in B73 x B84. Insufficient evidence was obtained to support the use of random mating in F(,2) populations from crosses of inbred lines to increase genetic variation

Security in online learning assessment towards an effective trustworthiness approach to support e-learning teams

(c) 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.This paper proposes a trustworthiness model for the design of secure learning assessment in on-line collaborative learning groups. Although computer supported collaborative learning has been widely adopted in many educational institutions over the last decade, there exist still drawbacks which limit their potential in collaborative learning activities. Among these limitations, we investigate information security requirements in on-line assessment, (e-assessment), which can be developed in collaborative learning contexts. Despite information security enhancements have been developed in recent years, to the best of our knowledge, integrated and holistic security models have not been completely carried out yet. Even when security advanced methodologies and technologies are deployed in Learning Management Systems, too many types of vulnerabilities still remain opened and unsolved. Therefore, new models such as trustworthiness approaches can overcome these lacks and support e-assessment requirements for e-Learning. To this end, a trustworthiness model is designed in order to conduct the guidelines of a holistic security model for on-line collaborative learning through effective trustworthiness approaches. In addition, since users' trustworthiness analysis involves large amounts of ill-structured data, a parallel processing paradigm is proposed to build relevant information modeling trustworthiness levels for e-Learning.Peer ReviewedPostprint (author's final draft

Reduction of speckle noise by using an adaptive window

Speckle noise is a multiplicative noise that results from random fluctuations of signals when they are reflected on a surface. This research article proposes a techniqueto reduce speckle noise by using classic statistical filters and a size-adaptivewindow. The advantage of using the mentioned window is that such filters show adequate performance at reducing noise and preserving edges. In fact, the resultss how that the measurement of absolute performance that can be obtained with thiswindow is better than the best results when the window is not used. Such better performance is expressed in terms of the signal / noise ratio, the edge improvement index and the mean square error

Coupling hydro-geo-chemical and isotopic approaches to assess the main factors controlling karst development in a fissure-dominated carbonate aquifer system (s-Spain)

Sierra Tejeda, Almijara and Albuñuelas mountains comprise a large outcrop (750 km² ca) of Triassic marbles in between of Málaga and Granada provinces in S Spain. They constitute a large entity carbonate aquifer system providing strategic groundwater resources for drinking water supply in sparse urban settlements and crops irrigation. The present research aims to refine the current hydrogeological knowledge of large-scale fissure-dominated carbonate aquifers regarding flow mechanisms and geochemical processes defining observed groundwater quality. To this, a two-year monitoring program of aquifer dynamics have been conducted in three selected discharge points (Fájara, Cijancos and Maro springs) showing characteristic spring responses. A combined approach based on the analysis of spring discharge and time series of selected hydrochemical and isotopic tracers (Na+, Ca+2, Mg+2, TA, TOC, Cl-, SO4-2 and δ13CTDIC) and on the geochemical calculations from the chemical signature of spring waters have been followed. The results indicate that the more bicarbonate enriched waters and the lowest hydrochemical variability of Cijancos spring, practically in all analyzed solutes, denotes a fissure type dominant flow system, while the larger variations in meteoric/soil tracers (Cl- and TOC) observed in Fajara spring chemograph as consequence of rainfall inputs characterize a karst drainage from a better hierarchized fracture-enlarged flow system. Maro spring waters are rich in Na+, Ca+2, Cl- and SO4-2, have higher δ13CTDIC amplitude and the temporal variations of major ions display marked dilutions after rainfall events followed by rapid recoveries of pre-event concentrations, evidence a complex flow system and variable groundwater source contribution. The chemical reactions deduced from the molar ratios of spring water chemistry are commonly CO2 dissolution and calcite dissolution, but also salt evapoconcentration in soil layer and gypsum dissolution in the case of Maro spring.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Reduction of speckle noise by using an adaptive window

Speckle noise is a multiplicative noise that results from random fluctuations of signals when they are reflected on a surface. This research article proposes a techniqueto reduce speckle noise by using classic statistical filters and a size-adaptivewindow. The advantage of using the mentioned window is that such filters show adequate performance at reducing noise and preserving edges. In fact, the resultss how that the measurement of absolute performance that can be obtained with thiswindow is better than the best results when the window is not used. Such better performance is expressed in terms of the signal / noise ratio, the edge improvement index and the mean square error

A collective intelligence approach for building student's trustworthiness profile in online learning

(c) 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Information and communication technologies have been widely adopted in most of educational institutions to support e-Learning through different learning methodologies such as computer supported collaborative learning, which has become one of the most influencing learning paradigms. In this context, e-Learning stakeholders, are increasingly demanding new requirements, among them, information security is considered as a critical factor involved in on-line collaborative processes. Information security determines the accurate development of learning activities, especially when a group of students carries out on-line assessment, which conducts to grades or certificates, in these cases, IS is an essential issue that has to be considered. To date, even most advances security technological solutions have drawbacks that impede the development of overall security e-Learning frameworks. For this reason, this paper suggests enhancing technological security models with functional approaches, namely, we propose a functional security model based on trustworthiness and collective intelligence. Both of these topics are closely related to on-line collaborative learning and on-line assessment models. Therefore, the main goal of this paper is to discover how security can be enhanced with trustworthiness in an on-line collaborative learning scenario through the study of the collective intelligence processes that occur on on-line assessment activities. To this end, a peer-to-peer public student's profile model, based on trustworthiness is proposed, and the main collective intelligence processes involved in the collaborative on-line assessments activities, are presented.Peer ReviewedPostprint (author's final draft

THREE-DIMENSIONAL CONTOURING WITH DIGITAL HOLOGRAPHY

Presentamos una técnica para determinar contornos tridimensionales de objetos con dimensiones de al menos cuatro órdenes de magnitud mayor que la longitud de onda de la iluminación. Nuestra propuesta esta basada en la reconstrucción numérica del frente de onda objeto a partir de un holograma registrado digitalmente. El mapa de fase módulo-2π requerido en cualquier proceso de contorneado es obtenido por medio de la substracción directa de dos imágenes de fase (imagen de diferencia de fase) de un objeto bajo diferentes ángulos de iluminación. La obtención de la imagen de diferencia de fase es posible gracias a la capacidad de reconstrucción numérica del campo óptico complejo proporcionado por la holografía digital. Esta característica particular nos proporciona un robusto, confiable y rápido procedimiento que sólo requiere de dos imágenes para su ejecución. La propuesta es soportada con el análisis teórico del sistema de contorneado y verificado por medio de resultados numéricos y experimentales.We report on a technique to determine the 3D contour of objects with dimensions of at least four orders of magnitude larger than the illumination optical wavelength. Our proposal is based on the numerical reconstruction of the object optical wave field of digitally recorded holograms. The re-quired 2π-module phase map in any contouring process is obtained by means of the direct subtraction of two phase-contrast images (phase-difference image) of a still object under different illumination angles. Obtaining phase difference images is only possible by using the capability of numerical reconstruction of the complex optical field provided by the digital holography. This unique characteristic leads us to a robust, reliable, and fast procedure that only requires of two images. We support our proposal with the theoretical means of numerical and experimental results.Presentamos una técnica para determinar contornos tridimensionales de objetos con dimensiones de al menos cuatro órdenes de magnitud mayor que la longitud de onda de la iluminación. Nuestra propuesta esta basada en la reconstrucción numérica del frente de onda objeto a partir de un holograma registrado digitalmente. El mapa de fase módulo-2π requerido en cualquier proceso de contorneado es obtenido por medio de la substracción directa de dos imágenes de fase (imagen de diferencia de fase) de un objeto bajo diferentes ángulos de iluminación. La obtención de la imagen de diferencia de fase es posible gracias a la capacidad de reconstrucción numérica del campo óptico complejo proporcionado por la holografía digital. Esta característica particular nos proporciona un robusto, confiable y rápido procedimiento que sólo requiere de dos imágenes para su ejecución. La propuesta es soportada con el análisis teórico del sistema de contorneado y verificado por medio de resultados numéricos y experimentales

Improvement of the signal-to-noise ratio in digital holography

Un problema fundamental en holografía óptica y digital es la presencia de ruido speckle en el proceso de reconstrucción, el cual disminuye considerablemente la relación señal ruido (SNR). Para muchas aplicaciones, esta reducción de la SNR hace que la holografía digital sea impráctica, de modo que gran número de alternativas se utilizan con el propósito de superar este problema. Estas alternativas van desde modificar la coherencia espacial de la iluminación a la aplicación de técnicas del procesamiento de imágenes. En este artículo proponemos el acople de técnicas del procesamiento digital de imágenes con la intención de incrementar esta SNR por medio de la reducción del ruido speckle en la reconstrucción digital de hologramas de Fresnel registrados ópticamente. Las técnicas propuestas son ilustradas con resultados experimentales.A fundamental problem in optical and digital holography is the presence of speckle noise in the reconstruction process, which essentially diminishes the signal to noise ratio (SNR). For many applications, that reduction of the SNR makes the digital holography impractical, so great number of approaches have been carried out in order to overcome such a problem. They range from modifying the spatial coherence of the illumination to the application of image processing techniques. In this paper we propose the merged use of digital image processing techniques in order to increase this SNR by reducing the speckle noise in the digital reconstruction of optically recorded Fresnel’s holograms. The proposed techniques are illustrated with experimental results.Un problema fundamental en holografía óptica y digital es la presencia de ruido speckle en el proceso de reconstrucción, el cual disminuye considerablemente la relación señal ruido (SNR). Para muchas aplicaciones, esta reducción de la SNR hace que la holografía digital sea impráctica, de modo que gran número de alternativas se utilizan con el propósito de superar este problema. Estas alternativas van desde modificar la coherencia espacial de la iluminación a la aplicación de técnicas del procesamiento de imágenes. En este artículo proponemos el acople de técnicas del procesamiento digital de imágenes con la intención de incrementar esta SNR por medio de la reducción del ruido speckle en la reconstrucción digital de hologramas de Fresnel registrados ópticamente. Las técnicas propuestas son ilustradas con resultados experimentales

Análisis de los contenidos más vistos en la historia de YouTube en España: posibles decisiones y futuros desafíos en torno al modelo de negocio de la plataforma

La plataforma gratuita de video streaming online YouTube cumplió una década en abril de 2015, contando con más de mil millones de usuarios —lo que viene a ser un tercio de todos los usuarios de internet—. Fue entonces cuando hizo público el ranking de los veinte videos más vistos en diez años en España. El presente trabajo analiza la relación de los contenidos de los videos vistos de la muestra, para entender mejor las posibles decisiones y futuros desafíos en torno al modelo de negocio de la plataforma, ya que desde que en 2006 Google comprara YouTube por unos 1.600 millones de dólares en acciones, el modelo de negocio sigue siendo incierto. The free online video streaming platform YouTube completed a decade in April 2015, with more than one billion users —a third of all Internet users—. It was then that it published the ranking of the twenty most viewed videos in ten years in Spain. The present work analyzes the relationship of the contents of the videos seen in the sample, to better understand the possible decisions and future challenges around the platform business model. Since Google bought YouTube in 2006 for about 1.6 billion US dollars in shares, the business model remains uncertain

Multitree-multiobjective multicast routing for traffic engineering

This paper presents a new traffic engineering multitreemultiobjective multicast routing algorithm (M-MMA) that solves for the first time the GMM model for Dynamic Multicast Groups. Multitree traffic engineering uses several trees to transmit a multicast demand from a source to a set of destinations in order to balance traffic load, improving network resource utilization. Experimental results obtained by simulations using eight real network topologies show that this new approach gets trade off solutions while simultaneously considering five objective functions. As expected, when M-MMA is compared to an equivalent singletree alternative, it accommodates more traffic demand in a high traffic saturated network.IFIP International Conference on Artificial Intelligence in Theory and Practice - Evolutionary ComputationRed de Universidades con Carreras en Informática (RedUNCI