1,210 research outputs found
On the Entanglement Entropy in Gaussian cMERA
The continuous Multi Scale Entanglement Renormalization Anstaz (cMERA) consists of a variational method which carries out a real space renormalization scheme on the wavefunctionals of quantum field theories. In this work we calculate the entanglement entropy of the half space for a free scalar theory through a Gaussian cMERA circuit. We obtain the correct entropy written in terms of the optimized cMERA variational parameter, the local density of disentanglers. Accordingly, using the entanglement entropy production per unit scale, we study local areas in the bulk of the tensor network in terms of the differential entanglement generated along the cMERA flow. This result spurs us to establish an explicit relation between the cMERA variational parameter and the radial component of a dual AdS geometry through the Ryu-Takayanagi formula. Finally, we argue that the entanglement entropy for the half space can be written as an integral along the renormalization scale whose measure is given by the Fisher information metric of the cMERA circuit. Consequently, a straightforward relation between AdS geometry and the Fisher information metric is also established.We thank Esperanza López for very fruitful discussions and a careful reading that helped to improve the manuscript. The work of JJFM is supported by Universidad de Murcia-Plan Propio Postdoctoral, the Spanish Ministerio de Economía y Competitividad and CARM Fundación Séneca under grants FIS2015-28521 and 21257/PI/19. JMV is funded by Ministerio de Ciencia, Innovación y Universidades PGC2018-097328-B-100 and Programa de Excelencia de la Fundación Séneca Región de Murcia 19882/GERM/15
Hábitos de lectura y conocimiento de la literatura de las maestras de educación infantil en formación
In pre-primary education, there is a need for specific research into developing awareness of literary genres that can be used in the EFL classes to promote literacy. A total of 264 students on the Teaching English for Pre-primary Education course participated on an online questionnaire adapted from Cremin et al. (2008), using both qualitative and quantitative questions to provide an insight into the issue. The first part of the questionnaire examined the reading habits of pre-service teachers. The second part probed into the specific knowledge of texts and authors in general for use in the EFL pre-primary classroom. The results showed that there is a very limited tradition of reading outside the EFL classroom from students’ experiences, that there is a very narrow catalogue of texts and genres that students are familiar with and lastly, that literature is primarily seen as a vehicle for vocabulary acquisition. Thus, it is essential to encourage future EFL teachers not only to become more knowledgeable about genres, but also aware of the different reasons to use literature in the classroom to promote literacy. En la educación infantil, es necesario realizar investigaciones específicas acerca del conocimiento del profesorado en formación sobre la variedad de géneros literarios disponibles para las clases de inglés como lengua extranjera para promover la alfabetización. 264 alumnas de Didáctica del Inglés para Educación Infantil participaron en un cuestionario en línea adaptado de Cremin et al. (2008) con preguntas cualitativas y cuantitativas. La primera parte examinó los hábitos de lectura de las maestras en formación. La segunda parte exploró el conocimiento específico de textos y autores en general para el aula de Educación Infantil. Los resultados mostraron que existe una tradición muy limitada de lectura a partir de las experiencias de las estudiantes, que el catálogo de textos y géneros con los que las estudiantes están familiarizadas es muy limitado y, por último, que la literatura se ve principalmente como un vehículo para la adquisición de vocabulario. Por lo tanto, es esencial alentar al futuro profesorado de inglés no solo a ser más conocedoras de los géneros, sino también a ser conscientes de las diferentes razones para usar la literatura en el aula para promover la alfabetización
Scanning electrochemical microscopy for the analysis and patterning of graphene materials: A review
[EN] Graphene and related materials have recently emerged as outstanding materials due to a range of properties such as high mechanical strength, high electron mobility, thermal conductivity, etc. Due to their high surface area and conductivity, graphene materials have also been used for electrochemical applications such as supercapacitors, batteries, sensors, etc. Therefore, the characterization of the electroactivity of graphene materials is necessary and different electrochemical techniques such as cyclic voltammetry and electrochemical impedance spectroscopy have been widely used for this purpose. Scanning electrochemical microscopy has appeared as a unique technique that can be used to test electron transfer kinetics, electroactivity and conductivity of these materials. Even patterns can be created on graphene materials by this technique, This review aims to compile the different works performed with graphene materials and scanning electrochemical microscopy technique and provide new perspectives into the analysis of graphene materials using this technique. (C) 2016 Elsevier B.V. All rights reserved.Authors wish to thank to the Spanish Ministerio de Ciencia e Innovacion (contract MAT2016-77742-C2-1-P) for the financial support. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship (APOSTD/2013/056). Tim Vickers is gratefully acknowledged for help with the English revision.Molina Puerto, J.; Fernández Sáez, J.; Cases Iborra, FJ. (2016). Scanning electrochemical microscopy for the analysis and patterning of graphene materials: A review. Synthetic Metals. 222:145-161. https://doi.org/10.1016/j.synthmet.2016.10.019S14516122
Los tarayales de la depresión del Ebro
La revisión de las comunidades de Tamarix en la depresión del Ebro permite reconocer tres asociaciones: Tamaricetum gallicae Br.-BI. & O. Bolós 1957 (Tamaricion africanae Br.-B1. & O. BoIós 1957), riparia y subhalófila; Agrostio-Tamaricetum canariensis Cirujano 1981 (Tamaricion boveano-canuriensis Izco, F. Fernández-González & A. Molina 1984), mesohalófila (subass. tamaricetosum canariensis) o hiperhalófila (subass. inuletosum crithmoidis nova); y Suaedo braun-blanquetii-Tamaricetum boveanae (Izco & al. 1984) ass.nova (Tamaricion boveano-canariensis), hiperhalófila y restringida a la parte más baja y oriental de la depresión.Tamarix-communities belonging to the order Tamaricetalia (class Nerio- Tamaricetea) are phytosociologically reviewed in the Ebro basin. Three associations can be differentiated: Tamaricetum gal/woe Br.-BI. & O. Bolós 1957 (Tamaricion africanae Br.-B1. & O. Bolós 1957), riparian and subhalophilous; Agrostio-Tamaricetum canariensis Cirujano 1981 (Tamaricion boveano-canariensis Izco, F. Fernández-González & A. Molina 1984), mesohalophilous (subass. tamaricetosum canariensis) or hiperhalophilous (subass. inuletosum crithmoidis nova); and Suaedo braun-blanquetii-Tamaricetum boveanae (Izco & al. 1984) ass.nova (Tamaricion boveano-canariensis), hiperhalophilous and restricted to eastern and lower part of the basin
Electrochemical study on an activated carbon cloth modified by cyclic voltammetry with polypyrrole/anthraquinone sulfonate and reduced graphene oxide as electrode for energy storage
[EN] This work describes a two-step procedure for the electrochemical coating of reduced graphene oxide (RGO) and polypyrrole anthraquinone sulfonate (PPyAQS) onto an activated carbon cloth (ACC) by cyclic voltammetry (CV). The textile samples were characterized by CV, electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge measurements using a sandwich-type (electrode/separator/electrode) cell designed to operate in three or two-electrode configurations. The presence of RGO onto the ACC surface optimized the electrosynthesis of PPyAQS and reinforced the stability of the polymer with the number of charge/discharge cycles. A retention capacity of 90% after 100 charge-discharge cycles together with an energy density of 7.8¿×¿10¿4¿W¿h¿cm¿2 at a power density of 1.8¿×¿10¿3¿W¿cm¿2 were obtained for the ACC/RGO/PPyAQS sample. The analyses by field emission scanning electron microscopy (FESEM) showed the RGO veils-like and PPyAQS glomerular structures covering the ACC-fibers. The Fourier transform infrared spectroscopy (FTIR) analyses not only detected the presence of PPy and AQS, but also, the changes in the molecular structure of PPyAQS, depending on its oxidation state, as consequence of the redox reactions occurred in the charge/discharge processes in the two-electrode cell.The authors wish to acknowledge to Chemviron Carbon who kindly
donated the ZORFLEX® activated carbon fabric. The authors wish to
thank the Spanish Agencia Estatal de Investigación de Economía (AEI)
and European Union (FEDER funds) for the financial support (contract
MAT2016-77742-C2-1-P). Tim Vickers is gratefully acknowledged for
help with the English revision. Electron Microscopy Service of the UPV
(Universitat Politècnica de València) is gratefully acknowledged for
help with FESEM characterization.Fernández Sáez, J.; Bonastre Cano, JA.; Molina Puerto, J.; Cases, F. (2018). Electrochemical study on an activated carbon cloth modified by cyclic voltammetry with polypyrrole/anthraquinone sulfonate and reduced graphene oxide as electrode for energy storage. European Polymer Journal. 103:179-186. https://doi.org/10.1016/j.eurpolymj.2018.04.018S17918610
Self-learning of Information Literacy Competencies in Higher Education: The Perspective of Social Sciences Students
Preference for autonomous versus directed learning for the acquisition of information competencies (ICs) was analyzed among undergraduate social science students
according to gender, degree program, belief in importance, and self-efficacy. Data
were gathered using the IL-HUMASS (Information Literacy Humanities Social Sciences)
online survey from students at five public Spanish universities enrolled in audiovisual
communication, education, information science, pedagogy, journalism, psychology,
social work, and tourism undergraduate programs during the 2013–2014 academic
year. Mann-Whitney U, Kruskal-Wallis, and chi-square tests, as well as discriminant
analysis, were performed. The results revealed a higher preference for the directed
learning style in the four IL competency categories: searching, evaluation, processing, and communication-dissemination. Audiovisual communication, education,
and journalism students showed a predilection for autonomous learning, whereas
information science and psychology students preferred directed learning. Higher
scores in belief in importance correlated with a greater preference for autonomous
learning. In contrast, higher levels of self-efficacy were associated with a greater
preference for directed learning.This research is part of the national
R&D Project “Innovación y formación en competencias informacionales de profesores y estudiantes universitarios
de ciencias sociales” (CSO2016-80147-R), financed by MINECO
Entanglement renormalization for interacting field theories
A general method to build the entanglement renormalization (cMERA) for interacting quantum field theories is presented. We improve upon the well-known Gaussian formalism used in free theories through a class of variational non-Gaussian wave functionals for which expectation values of local operators can be efficiently calculated analytically and in a closed form. The method consists of a series of scale-dependent nonlinear canonical transformations on the fields of the theory under consideration. Here, the lambda phi(4) and the sine-Gordon scalar theories are used to illustrate how nonperturbative effects far beyond the Gaussian approximation are obtained by considering the energy functional and the correlation functions of the theory.J.J.F.M. acknowledges A. Bhattacharyya and T. Takayanagi for useful discussions and comments. J.M.V. thanks J. Cotler and M. Muller for many fruitful discussions. The work of J.J.F. M. is supported by Universidad de Murcia. J.M.V. is supported by Ministerio de Economia y Competitividad FIS2015-69512-R and Programa de Excelencia de la Fundacion Seneca 19882/GERM/15. J.J.F. M. and E.T.L. acknowledge the financial support of Spanish Ministerio de Economia y Competitividad and CARM Fundacion Seneca under Grants No. FIS2015-28521 and No. 21257/PI/19
Determinants of leisure-time physical activity and future intention to practice in Spanish college students
Few studies analyze determinants and patterns of physical activity among college students, so it has not been possible to carry out effective interventions to promote this practice. The aim of this study was to analyze the associations between some personal, social, and environmental determinants, practice of physical activity and future intention to practice in a sample of 639 university students (321 men and 318 women), mean age 21.43 years (+/- 2.78). Physical fitness self-perception, physical activity history, and coach's support to practice physical activity have a direct effect on the practice of physical activity and an indirect effect on future intention to practice, both in men and women. The practice of physical activity has also a direct effect on future intention to practice. Likewise, the participation in sport competitions predicts practice of physical activity and future intention in men, whereas being a member of a sports club predicts practice and future intention in [email protected]; [email protected]
Development of carbon fiber acrylonitrile styrene acrylate composite for large format additive manufacturing
The increasing interest of Large Format Additive Manufacturing (LFAM) technologies in various industrial sectors mainly lies on the attainable production of pieces reaching several cubic meters. These new technologies require the development of optimized materials with two-folded capabilities, able to satisfy functional in-service requirements but also showing a proper printability. Acrylonitrile Styrene Acrylate (ASA) is among the most interesting thermoplastic materials to be implemented in a LFAM device due to its excellent wettability and mechanical properties. This research focuses on the development and characterization of ASA and carbon fiber (CF) ASA composites suitable for LFAM. The rheological, thermal and mechanical properties of neat ASA and ASA containing 20 wt% CF are addressed. The results evidence the higher performance of the CF loaded composite compared to the raw ASA polymer (i.e., the 20 wt% CF composite shows a 350% increase in flexural Young's Modulus and a 500% increment in thermal conductivity compared with neat ASA). Additionally, both materials were successfully printed along perpendicular directions (X and Z), showing the maximum tensile strain for the composite printed along the X orientation as was expected. The results of the flexural tests are comparable or slightly higher than those of injected parts. Finally, the fracture surface was analysed, identifying different types of porosity
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