Compact solvmanifolds with calibrated and cocalibrated G2-structures

We give a method to obtain new solvable 7-dimensional Lie algebras endowed with closed and coclosed G2-structures starting from 6-dimensional solvable Lie algebras with symplectic half-flat and half-flat SU(3)-structures, respectively. Provided the existence of a lattice for the corresponding Lie groups we obtain new examples of compact solvmanifolds endowed with calibrated and cocalibrated G2-structures. As an application of this construction we also obtain a formal compact solvmanifold with first Betti number b1=1 endowed with a calibrated G2-structure and such that does not admit any invariant torsion-free G2-structure

A Characterization of Van Hiele’s Level 5 of Geometric Reasoning Using the Delphi Methodology

The Van Hiele model of geometric reasoning establishes five levels of development, from level 1 (visual) to level 5 (rigor). Despite the fact that this model has been deeply studied, there are few research works concerning the fifth level. However, there are some works that point out the interest of working with activities at this level to promote the acquisition of previous levels. Our goal is to describe this level through the construction and validation of a list of indicators for each of the processes involved in geometrical reasoning (definition, proof, classification, and identification). Due to the lack of previous research, we have decided to use the Delphi methodology. This approach allowed us to collect information from a panel of experts to reach a consensus through a series of phases about the indicators that describe each of the processes. The final product of the iterative application of this method is a list of validated indicators of the fifth Van Hiele level of reasoning. In particular, proof and definition processes have turned out to be the most relevant processes at this level

Design of van Hiele’s level 5 indicators using the Delphi methodology

MICINN project PID2019-104964GB-I00 group S60_20R

Factores de desarrollo de las televisiones autonómicas públicas desde las percepciones de los grupos de interés: el caso de Aragón Televisión

La actual crisis económica, junto a los recientes cambios tecnológicos, legales y sociales producidos en la industria de la televisión, impulsa nuevos retos y oportunidades que deben ser abordados por todos los agentes que participan en la industria. Sin embargo, la literatura especializada carece de aportaciones que identifiquen grupos de interés y determinan la estructura de relaciones entre los mismos a través de puntos de interés común. Ante esta situación, el presente trabajo desarrolla una investigación cualitativa, con entrevistas en profundidad a expertos de la industria de la televisión autonómica pública de Aragón (cadena Aragón Televisión, ATV). Los resultados obtenidos permiten cubrir los objetivos del estudio descubriendo los factores de desarrollo a futuro de la industria audiovisual, en particular, para el caso de Aragón.The public television industry is confronting the current economic crisis and its financial problems related. This situation, joined to the technological, social and legal changes happening, derives in new challenges, which should be taken by every implied agent. However, the specialized literature falls in the identification of stakeholders and determining the relationships structure among them through common interest points. In this way, we develop a qualitative research, based on interviews to the experts, in the Aragon context (the study case of Aragon Television –ATV-, Spanish region). We use a qualitative methodology based on interviews to the experts of the audiovisual industry. Our results provide a better understanding of the audiovisual industry by identifying their stakeholders and the relationships between stakeholders and the regional public media. We obtain the development factors of this industry from stakeholders’ perceptions

Solutions of the Laplacian flow and coflow of a locally conformal parallel G2-structure

We study the Laplacian flow of a G 2-structure where this latter structure is claimed to be locally conformal parallel. The first examples of long time solutions of this flow with the locally conformal parallel condition are given. All of the solutions are ancient and Laplacian soliton of shrinking type. These examples are one-parameter families of locally conformal parallel G2-structures on rank-one solvable extensions of six-dimensional nilpotent Lie groups. The found solutions are used to construct long time solutions to the Laplacian coflow starting from a locally conformal parallel structure. We also study the behavior of the curvature of the solutions obtaining that for one of the examples the induced metric is Einstein along all the flow (resp. coflow)

Laplacian coflow for warped G2-structures

We consider the Laplacian coflow of a G2-structure on warped products of the form M7=M6×fS1 with M6 a compact 6-manifold endowed with an SU(3)-structure. We give an explicit reinterpretation of this flow as a set of evolution equations of the differential forms defining the SU(3)-structure on M6 and the warping function f. Necessary and sufficient conditions for the existence of solution for this flow are given. Finally we describe new solutions for this flow where the SU(3)-structure on M6 is nearly Kähler, symplectic half-flat or balanced. © 2020 Elsevier B.V

Tourism Distribution System and Information and Communication Technologies (ICT) Development: comparing Data of 2008 and 2012

Information and Communication Technologies (ICTs) and the development of the online channel have transformed the competitive environment of the tourism industry within a brief span of time. However, our knowledge about the details of the evolving trend of the distribution system is scarce. Considering the prior literature, this research analyzes the evolution of the sector’s structure, the power of tourism operators, the production processes and products of the tourism sector. The work uses primary information which is taken from surveys to experts in the sector, within a European context. The results of the work, based on a comparison between two samples in 2008 and in 2012, underscore the development of the distribution system and the significant changes happened in opinions regarding the relationship between the use of ICTs and value creation, regarding ICTs and product quality, and regarding how ICTs facilitate the adoption of the best practices in the industry. Multiple and exclusively online channel strategies are the most involved

Proof levels of graph theory students under the lens of the Van Hiele model

This work is devoted to exploring proof abilities in graph theory of undergraduate students of the Degree in Computer Engineering and Technology of the University of Seville. To do this, we have designed a questionnaire consisting of five open-ended items that serve as instrument to collect data concerning their proof skills when dealing with graphs. We have thus analysed them adapting the methodology for computing the degrees of acquisition of the Van Hiele levels. Our analysis leads to different proof profiles of graph theory students whose characteristics provide empirical support to consider proof levels in graph theory froThis work is devoted to exploring proof abilities in Graph Theory of undergraduate students of the Degree in Computer Engineering and Technology of the University of Seville. To do this, we have designed a questionnaire consisting of five open-ended items that serve as instrument to collect data concerning their proof skills when dealing with graphs. We have thus analysed them adapting the methodology for computing the degrees of acquisition of the Van Hiele levels. Our analysis leads to different proof profiles of Graph Theory students whose characteristics provide empirical support to consider proof levels in Graph Theory from the perspective of the Van Hiele model.m the perspective of the Van Hiele model