Irreversible flow of vortex matter: polycrystal and amorphous phases

We investigate the microscopic mechanisms giving rise to plastic depinning and irreversible flow in vortex matter. The topology of the vortex array crucially determines the flow response of this system. To illustrate this claim, two limiting cases are considered: weak and strong pinning interactions. In the first case disorder is strong enough to introduce plastic effects in the vortex lattice. Diffraction patterns unveil polycrystalline lattice topology with dislocations and grain boundaries determining the electromagnetic response of the system. Filamentary flow is found to arise as a consequence of dislocation dynamics. We analize the stability of vortex lattices against the formation of grain boundaries, as well as the steady state dynamics for currents approaching the depinning critical current from above, when vortex motion is mainly localized at the grain boundaries. On the contrary, a dislocation description proves no longer adequate in the second limiting case examined. For strong pinning interactions, the vortex array appears completely amorphous and no remnant of the Abrikosov lattice order is left. Here we obtain the critical current as a function of impurity density, its scaling properties, and characterize the steady state dynamics above depinning. The plastic depinning observed in the amorphous phase is tightly connected with the emergence of channel-like flow. Our results suggest the possibility of establishing a clear distinction between two topologically disordered vortex phases: the vortex polycrystal and the amorphous vortex matter.Comment: 13 pages, 16 figure

Descripción y caracterización de micorrizas de los géneros Tuber y Genea de una formación natural de carrasca (Quercus ilex L. subsp. ballota (Desf.) Samp.).

En las últimas décadas se ha producido un incremento muy importante del número de ectomicorrizas descritas. Así mismo, estas descripciones han pasado de ser muy someras a ser muy detalladas, incluyendo no solo caracteres morfológicos, sino también anatómicos. Sin embargo, las ectomicorrizas de hongos hipógeos siguen siendo, en general muy desconocidas, dado que son muy pocas las especies descritas en detalle hasta el momento. En el presente trabajo se describen y caracterizan cuatro micorrizas de los géneros Tuber y Genea reconocidas en un carrascal maduro (Quercus ilex L. subsp. ballota (Desf.) Samp.) de Navarra, con el objetivo de aportar datos que contribuyan a su identificación

A comparison of numerical approaches for the design of mooring systems for wave energy converters

This paper analyses the numerical outcome of applying three different well-known mooring design approaches to a floating wave energy converter, moored by means of four catenary lines. The approaches include: a linearized frequency domain based on a quasistatic model of the mooring lines, a time domain approach coupled with an analytic catenary model of the mooring system, and a fully coupled non-linear time domain approach, considering lines' drag and inertia forces. Simulations have been carried out based on a set of realistic combinations of lines pretension and linear mass, subject to extreme environmental conditions. Obtained results provide realistic cost and performance indicators, presenting a comparison in terms of total mooring mass and required footprint, as well as the design line tension and structure offset. It has been found that lines' viscous forces influence significantly the performance of the structure with high pretensions, i.e., >1.2, while there is acceptable agreement between the modelling approaches with lower pretensions. Line tensions are significantly influenced by drag and inertia forces because of the occurrence of snap loads due to the heaving of the floater. However, the frequency domain approach provides an insight towards the optimal design of the mooring system for preliminary designs

User involvement before the development of an indoor RPAS for the creative industries

[EN] This paper presents user needs and preferences gathered prior to the development of an indoor remotely piloted air system. A literature review was carried out to analyse previous studies about the involvement of users in the design of indoor unmanned aerial vehicles. Subsequently, the results of these user needs obtained from three focus groups held in European countries (Belgium, Spain and United Kingdom) are presented here. Through a content analysis of the information obtained in the focus groups, 40 codes and 4 variables were defined and used to examine the differences between types of users and their previous experience with drones. The literature review gave support to the results obtained through users¿ involvement in the features to be included in a new unmanned aerial vehicle. Non-parametric tests and qualitative comparative analysis were used to analyse the information gathered in the focus groups. The results revealed few differences between artists working in creative industries and drone operators working for the creative industries. These differences affected features such as detecting and avoiding obstacles, which requires the inclusion of sensors. In addition, previous experience with drones was found to be a sufficient condition to explain greater concerns over safety, ethical and security issues in indoor environments.The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: This work was supported by the European Commission (H2020, grant number 732433).De-Miguel-Molina, B.; De-Miguel-Molina, M.; Santamarina-Campos, V.; Segarra-Oña, M. (2021). User involvement before the development of an indoor RPAS for the creative industries. International Journal of Micro Air Vehicles. 13:1-14. https://doi.org/10.1177/17568293219921401141

A revision of the descriptions of ectomycorrhizas published since 1961

All available publications providing descriptions of ectomycorrhizas (ECM) were reviewed in order to build a database containing details on fungus forming the ECM, host tree, country where the material for description was collected, and habitat of the ECM. Other secondary data were also recorded. In all 1244 descriptions of ECM published since 1961 in 479 papers were reviewed. The number of different ECM morphotypes described was 814. Most ECM described were collected in Europe and North America. Gymnosperms were the most common tree associates, and boreal and temperate forests the most studied ecosystems. Fungal symbionts were mostly Basidiomycota, epigeous, and with mushroom-like morphology. The paper also addresses the gaps in ECM knowledge that mycorrhizologists should address in future studies

Čech-completeness and ultracompleteness in “nice spaces”

summary:We prove that if $X^n$ is a union of $n$ subspaces of pointwise countable type then the space $X$ is of pointwise countable type. If $X^\omega$ is a countable union of ultracomplete spaces, the space $X^\omega$ is ultracomplete. We give, under CH, an example of a Čech-complete, countably compact and non-ultracomplete space, giving thus a partial answer to a question asked in [BY2]

Comparison of the post-fire dynamics of the ectomycorrhizal community in two Quercus ilex stands in Northern Spain

A comparative study of the post-fire recolonization of ectomycorrhizae in two evergreen oak stands (Quercus ilex L. subsp. ballota (Desf.) Samp.) in Nazar and San Cristóbal (Navarra, Spain) has been carried out. In 1993 a stand in Nazar burnt, but it was not until 1998 that the study started. On the contrary, the study in San Cristóbal started immediately after the stand had caught fire in 2000. Therefore we have been able to compare the regeneration in both stands and the species composition five years after the fire and immediately after the fire, as well as the differences in ectomycorrhizal colonization and abundance of morphotypes between the burnt plots and areas which remained undisturbed in both forests, thus acting as control plots. In both sites the percentage of ectomycorrhizal colonization tended to be lower after the wildfire. In San Cristóbal, in the burnt site there was a lower abundance of morphotypes compared to the control site. However, in Nazar, five years after the fire, we did not find any significant change in species richness, but rather a shift in the abundance of each morphotype when comparing the burnt and the control plots. There are some species of mycorrhizal fungi which seem to be particularly adapted to fire, such as Type 1 in San Cristóbal and Cenococcum geophilum in Nazar. Sphaerosporella brunnea, a pioneer species considered to be especially suitable for the colonization of burnt substrates, was only found in Nazar

Art Thinking as a catalyst for STEAM strategies. Towards a divergent thinking

[EN] Practical training in the university environment, without attention to creativity and innovative thinking, is not very effective. For this reason, we have tried to find a new learning model, which focuses on the disciplines essential for the future, through an interdisciplinary approach. The use of tools such as Art Thinking and the search for new learning spaces, sometimes outside the classroom and in others transforming the classroom space itself into a ¿corner to dream¿, have allowed us to create a conducive climate to the development of creativity and to discover that the combination of technical training with skills associated with the artistic field, are positioned as the ideal way to train the professionals of the future. Thus, within the strategy of reaching professional competences, it is planned to work jointly and collaboratively between the creative, technological and management disciplines that coexist on the campus of the Universitat Politecnica de Valencia, in the implementation of new training spaces, which favor the acquisition of transversal competences and strengthen the teaching and learning process through visible and responsible learning by means of STEAM strategies.This work has been developed within the project Applying STEAM strategies in the Social Sciences and Arts areas by means of a Service-learning methodology, conducted by Professor María deMiguel-Molina, and with the support of the Universitat Politécnica de València (Science Education Institute, ICE). Moreover, this paper's authors belong to the team Reality baths: towards a visible, responsible and innovative learning, coordinated by Professor Virginia Santamarina-Campos.Santamarina-Campos, V.; De-Miguel-Molina, M.; De-Miguel-Molina, B.; Carabal-Montagud, M. (2020). Art Thinking as a catalyst for STEAM strategies. Towards a divergent thinking. Iated. 766-774. https://doi.org/10.21125/inted.2020.0288S76677

Use of infographics by students in business degrees

[EN] This paper presents the introduction of infographics in two courses during the academic year 2020-2021. These courses are from bachelor studies in a faculty of Business Administration and Management. This type of visualization was used by students as a support for summarising and communicating their ideas. To do it, different tasks were designed and some applications were proved by students. The experiences explained include the learning objectives that were settled, the activities designed, and the pros and cons of the applications used. An infographic is a visualization that offers a combination of image, text and chart. This enables grouping STEAM competences in a same task while improving communication skills of students. In the experiences described in this papers, image (arts), data (maths) and text are combined to reinforce the data included. Moreover, technology is incorporated through infographic applications as a digital support for students in online sessions. Another advantage of an infographic is that it allows to transmit important information in a visual and easy way, which facilitates the reader to understand the message even when it is supported by scientific rigor. If its power to illustrate more complete stories is considered, the reason why its use has been extended in the last decade to communicate many different topics, such as data about health, environment and sciences, is clear. When designing an infographic, the three main features to be considered in its structure are the content, the visual and the story. With respect to the content, it is important to consider the target of the infographic, the main where it will be displayed and the order that the story will be explained. The visual aspect will help to communicate the content. For example, using some icons to stablish an order in the story. Making use of different size in letters, might highlight the main sentences in the visual. The story will help to understand the information to be transmitted. In this paper tasks presented for the two courses are: a) the use of infographics by students to summarise main ideas in some sections of the bachelor¿s degree thesis and b) an infographic used by students after organising information from users¿ opinions in an affinity map. The task in the first course aims that students design an infographic for a section in their bachelor¿s degree thesis. The profile of students in the course will result in many potential themes in their thesis and, thus, in various types of infographics. The learning outcome from the task would be that they are able to convert a difficult section in an understandable message, although maintaining the academic rigor. The task in the second course aims that students organise user¿s opinions from a service in an affinity map. After analysing opinions in social networks and conducting interviews with users, they should communicate the main results in an infographic. Results obtained from the two experiences differ depending on whether the task was carried out individually or in team, the session was face-to-face or online, and students worked in a same theme or not.This paper was written as part of two innovation and educational improvement projects (PIME) with the support of the Universitat Politècnica de València (Institute of Educational Sciences, ICE). The first project is entitled "Applying STEAM strategies in the areas of Social Sciences and Arts, through ServiceLearning activities", and is coordinated by Professor María de-Miguel-Molina. The second project is entitled ¿Infographics: Using ICT in the visual and creative representation of teaching content¿, and is coordinated by Professor María-Angeles Carabal-Montagud.De-Miguel-Molina, B.; De-Miguel-Molina, M.; Santamarina-Campos, V.; Carabal-Montagud, M. (2021). Use of infographics by students in business degrees. IATED Academy. 4470-4475. https://doi.org/10.21125/edulearn.2021.0936S4470447