665 research outputs found

    A technique for designing glossary activities with facial authentication

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    Nowadays, one of the key challenges for distance education is to be able to verify the students’ identity in order to check if they are actually who they claim to be when they are doing their online tasks and to avoid identity thief. This can be achieved through facial authentication software. In e-learning, thanks to this technology there is a way to confirm that the students are not committing fraud in their studies and besides to improve this kind of education by equaling its validity and prestige to traditional face-to-face education. The goal of this research is to avoid fake users that perform educational tasks on behalf of others in the Learning Management Systems (LMSs), and more specifically to develop a new technique to design activities with glossaries that properly allow control of the student learning process through facial authentication software. The presented technique is composed of several steps that guide instructors in the elaboration of this kind of activities. This work has used Moodle platform for the experimentation, and analyzes the experience of 67 students with the activities designed with the presented technique

    Neutronic Evaluation of Using a Thorium Sulfate Solution in an Aqueous Homogeneous Reactor

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    Radioisotope 99Mo is one of the most essential radioisotopes in nuclear medicine. Its production in an Aqueous Homogeneous Reactor (AHR) could be potentially advantageous compared to the traditional technology, based on target irradiation in a heterogeneous reactor. An AHR conceptual design using low-enriched uranium for the production of 99Mo has been studied in depth. So far, the possibility of replacing uranium with a non-uranium fuel, specifically a mixture of 232Th and 233U, has not been evaluated in the conceptual design. Therefore, the studies conducted in this article aim to evaluate the neutronic behavior of the AHR conceptual design using thorium sulfate solution. Here, the 232Th-233U composition to guarantee ten years of operation without refueling, conversion ratio, medical isotopes production levels, and reactor kinetic parameters were evaluated, using the computational code MCNP6. It was obtained that 14 % 233U enrichment guarantees the reactor operation for ten years without refueling. The conversion ratio was calculated at 0.14. The calculated 99Mo production in the AHR conceptual design resulted in 24.4 % higher with uranium fuel than with thorium fuel

    Modelling and Inference with Conditional Gaussian Probabilistic Decision Graphs*

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    Probabilistic decision graphs (PDGs) are probabilistic graphical models that represent a factorisation of a discrete joint probability distribution using a “decision graph”-like structure over local marginal parameters. The structure of a PDG enables the model to capture some context specific independence relations that are not representable in the structure of more commonly used graphical models such as Bayesian networks and Markov networks. This sometimes makes operations in PDGs more efficient than in alternative models. PDGs have previously been defined only in the discrete case, assuming a multinomial joint distribution over the variables in the model. We extend PDGs to incorporate continuous variables, by assuming a Conditional Gaussian (CG) joint distribution. We also show how inference can be carried out in an efficient way

    La independencia

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    Este libro recopila los artículos que publico el periódico literario "El Repertorio", durante las fiestas del primer Centenario del 5 de noviembre de 1811

    Improved prediction of the optical properties in pi-conjugated polymers: the case of benzochalcogenodiazole-based copolymers with different heteroatom substitution

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    Donor−acceptor (D−A) approach to conjugated polymer design has become a widely used method for preparing conjugated polymers with narrow band gaps.1 One outstanding D−A polymer is poly(cyclopentadithiophene)benzothiadiazole, PCPDTBT (P1 in Figure 1), for which power conversion efficiencies in solar cells of 4.5-5.5% are reported.2 In this work, we use resonance Raman (RR) and density functional theory (DFT) calculations to investigate the tuning of the electronic and structural properties of cyclopentadithiophene-benzochalcogenodiazole D−A polymers, wherein a single atom in the benzochalcogenodiazole unit is varied from sulfur to selenium to tellurium (Fig. 1).3 Sophisticated DFT calculations have been carried out using long-range corrected functionals, considering both tuned and default range-separation parameters, aiming at predicting their optical and charge transport properties. In addition, the nature of the electronic excitation is described by analyzing the enhancement pattern in the RR spectra using Raman excitation wavelengths coincident with the various transitions in the copolymers.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Exploring the influence of facial verification software on student academic performance in online learning environments

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    In spite of the advances in technology in the e-learning field during the last decades, there is still a gap of software and tools that actually improve the assessment of this kind of education by preventing students from cheating when they perform their activities online. Currently, most learning management systems do not offer enough tools or characteristics to check that students are who they assure when they carry out their exercises or online tests. Facial verification software can be considered an interesting tool to answer this need. This facial software helps to verify the identity of the students when they perform their activities, with the intention of confirming whether they are who they claim to be. However, its use could modify the academic results of the students due to psychological factors (e.g. they could feel spied, ashamed or too controlled). The aim of this article is to investigate whether the utilization of facial verification software can modify the academic performance of students in their online activities. In this work, the grades of 70 master students were analyzed and the conclusions pointed out that the academic performance obtained by the students is similar for both groups: those who have used facial authentication and those who did not use it

    Desde el margen: Teatro alterno y comunidades hispanas de Nueva York, 1997–2017

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    Esta disertación analiza ocho textos de los autores Tere Martínez, Jorge Merced, Marco Antonio Rodríguez, Eva Cristina Vásquez y cuatro performances en la calle. La misma explora las relaciones entre los cuatro dramaturgos y las comunidades hispanas de Nueva York. Indaga en el proceso de cómo la memoria de estas comunidades se refleja en un repertorio teatral. Por otro lado, revisa la organización del performance cultural en las comunidades. La hipótesis de esta investigación es que en el teatro hispano alterno hay obras que son reflejo y reflexión sobre los grupos periféricos y que el performance es una herramienta social. --- This dissertation analyzes eight texts by playwrights Tere Martínez, Jorge Merced, Marco Antonio Rodríguez, and Eva Cristina Vásquez. It explores the relationships between the mentioned authors and the Hispanic communities of New York City, principally the process of how history and memories of these communities are reflected in a theatrical repertoire. On the other hand, Desde el margen explores four cultural and social performances performed on streets by neighbors or social activists reviewing the organization of these performances developed by Hispanic groups. The hypothesis of this research is that in the alternative Hispanic theater there are works that reflect Hispanic peripherical groups and that performing arts and theater are social tools. The dissertation’s theoretical framework are Performance Studies and Latinx Studies

    Metallicity determination in gas-rich galaxies with semiempirical methods

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    A study of the precision of the semiempirical methods used in the determination of the chemical abundances in gas-rich galaxies is carried out. In order to do this the oxygen abundances of a total of 438 galaxies were determined using the electronic temperature, the R23R_{23} and the P methods. The new calibration of the P method gives the smaller dispersion for the low and high metallicity regions, while the best numbers in the turnaround region are given by the R23R_{23} method. We also found that the dispersion correlates with the metallicity. Finally, it can be said that all the semiempirical methods studied here are quite insensitive to metallicity with a value of 8.0±0.28.0\pm0.2 dex for more than 50% of the total sample. \keywords{ISM: abundances; (ISM): H {\sc ii} regions}Comment: 26 pages, 9 figures and 2 tables. To appear at AJ, January 200

    Estratigrafía y petrología del subsuelo recuaternario del sector sw de la depresión de Barcelona (cadenas costeras catalanas, ne de Iberia)

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    [email protected] numerosas obras de Ingeniería Civil que se han realizado en los últimos años en la depresión de Barcelona (ampliación del aeropuerto, ampliación del metro y AVE fundamentalmente) han permitido recabar mucha información sobre el subsuelo de esta área. En este trabajo se caracterizan las distintas unidades de subsuelo precuaternarias que aparecen en los numerosos sondeos realizados recientemente en la zona SW de la depresión de Barcelona. Se ha identificado un sustrato triásico formado por areniscas del Buntsandstein y dos unidades de edad Miocena, una basal de carácter continental y otra superior depositada en un ambiente marino. Todas estas unidades fueron fracturadas debido a una tectónica extensiva y, posteriormente, fueron fosilizadas en primer lugar por los sedimentos del Plioceno, que recubren la superficie de erosión messiniense, y finalmente, por el Cuaternario. El análisis de las distintas unidades permite obtener datos sobre la evolución paleogeográfica y tectónica de la depresión de Barcelona durante el Mioceno y el Plioceno.Current building of civil Engineering infrastructures in the Barcelona plain and Llobregat delta (mainly metro and airport extension and high speed train) is providing new geological subsurface data to build better geologic models and understand the basin evolution. This work focuses on the pre-Quaternary units observed in cores. Based on petrographic analyses combined when it was possible with paleontological studies, we identified the lower Triassic Buntsandstein sandstone facies and Miocene continental and marine facies which appear compartmentalized due to extensive deformation. After this extensive episode, Pliocene and Quaternary sediments, which were deposited after the development of successive erosive surfaces, overlay the Triassic and Miocene units. The identification of these units enabled one to improve the interpretation of the tectonic and paleogeographic evolution of the Barcelona plain

    Teachers' digital competence to assist students with functional diversity: Identification of factors through logistic regression methods

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    We are experiencing a serious health crisis due to COVID-19 that has a major impact on the field of education. The educational system therefore needs to be updated and innovated, with the addition of digital resources, to adapt the teaching and learning processes to students with disabilities. To meet the goal of high-quality education, teachers must have adequate digital competence to face the educational demands that are placed on them. Therefore, the purposes of this study are: to know the teachers' knowledge about digital resources to support students with disabilities (O1); at each educational stage (O2), identify the variables that have a significant impact on the acquisition of teacher competence (O3); propose a selection of useful ICT resources for each type of disability (O4). An ex post facto design was used with 1194 teachers from Andalusia (Spain). The results showed the medium-low level of the teaching staff, especially in the higher education stage. In addition, gender, motivation, attitude and having students with special needs are determining factors in the development of teacher knowledge. The results highlight the urgent need for teachers to be trained in digital resources. We hope that the range of resources proposed in this study will help teachers enhance their teaching practice
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