Rotating and counterrotating relativistic thin disks as sources of stationary electrovacuum spacetimes

A detailed study is presented of the counterrotating model (CRM) for electrovacuum stationary axially symmetric relativistic thin disks of infinite extension without radial stress, in the case when the eigenvalues of the energy-momentum tensor of the disk are real quantities, so that there is not heat flow. We find a general constraint over the counterrotating tangential velocities needed to cast the surface energy-momentum tensor of the disk as the superposition of two counterrotating charged dust fluids. We then show that, in some cases, this constraint can be satisfied if we take the two counterrotating tangential velocities as equal and opposite or by taking the two counterrotating streams as circulating along electro-geodesics. However, we show that, in general, it is not possible to take the two counterrotating fluids as circulating along electro-geodesics nor take the two counterrotating tangential velocities as equal and opposite. A simple family of models of counterrotating charged disks based on the Kerr-Newman solution are considered where we obtain some disks with a CRM well behaved. We also show that the disks constructed from the Kerr-Newman solution can be interpreted, for all the values of parameters, as a matter distribution with currents and purely azimuthal pressure without heat flow. The models are constructed using the well-known "displace, cut and reflect" method extended to solutions of vacuum Einstein-Maxwell equations. We obtain, in all the cases, counterrotating Kerr-Newman disks that are in agreement with all the energy conditions.Comment: 22 pages, 7 figures, Late

Alternative operators investing in NGNs: A causal analysis of the case in Spain

The telecommunications market was completely open to competition in 1998 in Spain, as in most EU countries. The model for the liberalization of the market was based on the regulated use of the incumbent operators' network, so that new entrants could initially use these resources to allow for a soft entry in the market, by climbing a 'ladder of investment'. However, as late as 2011, no entrant operator had gone beyond the Unbundled Local Loop deploying its own access network. This changed in Spain in 2012, when Jazztel decided it would invest in deploying Fibre-to-the-Home. Later, Orange and Vodafone announced that they have reached an agreement to share the deployment of fibre to 6 Millions of households. This phenomenon has coincided in time with the lack of regulated wholesale access on Telefónica FTTH network for speeds above 30 Mbps. In this paper, we show the causality between both events (lack of actual regulated wholesale access to the fibre, deployment by alternative operators), by understanding competition as a process, in the Hayekian and Schumpeterian tradition

Development of Interactive Materials by Engineering Students Using the Descartes Applets.

In a degree course such as Forestry Engineering, the general teaching objectives consist of explaining and helping students to understand the principles of Mechanics. For some time now we have encountered significant difficulties in teaching this subject due to the students' lack of motivation and to their insufficient prior preparation for the topic. If we add to this the discipline's inherent complexity and the students' preconceptions about the subject, these teaching difficulties become considerable. For this reason a series of didactic activities have been introduced sequentially in the teaching of this subject. This work describes the methodology, procedure and results for the action of developing a work project in groups using Descartes software. The results of this experiment can be considered very positive. Some of the critical preconceptions for learning the subject can be corrected, and the tutoring process in the classroom contributes to an improvement in teacherstudent communication. Since this scheme was established, the number of students taking part each academic year has increased, and this is the group with the greatest percentage of passing scores

Effect of fiber inclusion in the rearing diets and energy concentration of the laying diets on productive performance and egg quality of brown egg-laying hens from 18 to 46 weeks of age

Una práctica común para mejorar el consumo de alimento en gallinas jóvenes al inicio de la puesta consiste en aumentar el contenido de fibra de las dietas de recría. La inclusión de fibra podría favorecer la adaptación del tracto gastrointestinal (TGI) del ave para tener un mayor consumo durante la fase de puesta, lo que puede mejorar la productividad de las gallinas. El diseño experimental fue completamente al azar con un modelo factorial con 12 tratamientos con 6 dietas en la fase de recría (0-17semanas) y 2 dietas en la fase de puesta (17-46 semanas). Dos de las dietas de la fase de recría se basaron en cebada o maíz y las 4 dietas restantes se agruparon en un modelo factorial 2x2 con 2 fuentes de fibra (paja y pulpa de remolacha) incluidas a niveles de 2 ó 4% en la dieta a base de maíz. En la fase de puesta, la mitad de las pollitas de estos 6 tratamientos se alimentaron con dietas con 2.650 kcal AMEn / kg y la otra mitad con 2.750 kcal AMEn / kg, con el mismo contenido de nutrientes por unidad de energía. No se encontraron interacciones entre las dietas de fase de recría y las de fase de puesta. El tipo de dieta en la fase de recría no afectó a la productividad de las gallinas o al peso relativo (% peso vivo) del TGI, el pH del contenido de la molleja, o la longitud relativa de las gallinas (cm / kg de peso vivo) o del intestino delgado. Las gallinas alimentadas con la dieta alta en energía durante la fase de puesta comieron menos alimento (P <0,001), pero presentaron mejor índice de conversión (P <0,01) y una mayor ganancia de peso (P <0.05) que las gallinas alimentadas con la dieta baja en energía. La calidad del huevo no se vio afectada por el tratamiento a excepción de la incidencia de huevos sucios, que fue mayor (P <0,001) para la dieta baja en energía. En conclusión, ni el tipo de cereal ni la inclusión de fuentes de fibra en las dietas de recría, afectaron al desarrollo del TGI ni a la producción de las gallinas a 46 semanas de edad. Además, el uso de dietas de alta energía durante la fase de puesta reduce el consumo medio diario y mejora el índice de conversión, sin afectar a la producción de huevos o al peso del huevo

Automatization of Harmful Algal Bloom early warning services: an example in Galicia (NW Spain)

Predicting Risk and Impact of Harmful Events in the Aquaculture SectorPRIMROS

Methods for causality assessment of idiosyncratic drug-induced liver injury

The diagnosis of idiosyncratic drug-induced liver injury (DILI) is a challenging task due to the lack of specific features or definitive diagnostic tools. A minimum of clinical and pharmacological information is required, together with laboratory and imaging tests to exclude other causes of liver injury. Several standardized methods have been developed to support clinical judgement and establish causality assessment, the most widely used being the Roussel Uclaf Causality Assessment Method—RUCAM— and structured Expert Opinion. More recently, an evidence-based, revised RUCAM, Electronic Causality Assessment Method—RECAM—has been developed and, although still a work in progress, may replace RUCAM scoring in the future. International collaborative networks and ongoing research efforts are key to advancing biomarker qualification and validation and developing new in vitro patient-based methods that will help improve DILI diagnosis and move towards a personalized medicine approach.Funding for open access charge: Universidad de Málaga / CBUA. This research was supported by grants from the Instituto de Salud Carlos III, cofounded by the Fondo Europeo de Desarrollo Regional-FEDER contract numbers: PI21/01248; PID2022-140169OB-C21, PT23/00137. Cofounded by European Union. CIBERehd and Plataforma de Investigación Clinica are funded by the Instituto de Salud Carlos III. G.M.C. holds a FPU PhD fellowship from the Spanish Ministry of Science, Innovation and Universities (FPU22/03868). The funders had no role in study design, data collection and analysis, decision to publish or prepare the manuscript

New evidences to know the Late Antiquity in Cerro de Tormejón (Armuña, Segovia, Spain)

El propósito de este trabajo es ampliar la información existente sobre la fase tardoantigua en el Cerro Tormejón a través del análisis tanto de los materiales recuperados hace unos años en él, con motivo de la realización de una campaña de excavación, como de otros procedentes de varios trabajos de prospección. Esta nueva documentación y la disponible en la bibliografía arqueológica nos ha permitido concretar aspectos relativos a los siglos V y VI d. C. en el área segoviana del corredor del Eresma.The aim of this paper is to show a Late Antiquity pottery collection from Tormejón hillfort, a settlement located near Eresma river, between the roman cities of Segovia and Cauca (Coca). Our principal support of analysis is an ancient archaeological excavation conduced by one of us and other evidences from intensive survey. With the combination of this material evidences and the little notices of other archaeologists who write about this site, we want to make a synthesis of knowledge for this period

An unpublished legacy of Antonio Rubio Marín (1884-1980), an architect between Aragon and Madrid

Este documento se considera que es un capítulo de libro en lugar de un congresoAn unpublished legacy of the architect Antonio Rubio Marín has been found in the library of the University of Alcalá. He was an important an architect of the first half of the twentieth century in Madrid and Aragon, being responsible in Zaragoza for the Post Office building and the Grand Hotel. Still in a state of certain abandonment, the legacy has great interest for its documentary quality, being a fairly complete set of the activity of an architect of the early twentieth century. Antonio Rubio combined other notable merits, such as his training as a mathematician and cartographer, or his work as dean of the College of Architects of Madrid between 1948 and 1954. The inventory and cataloging process of the material found by researchers from the School of Architecture of the University of Alcala is currently being carried out, with the collaboration of his family and those responsible for the archiving of the same University. The legacy contains an important variety of drawings of different types. Most of them are freehand drawings in ink, in different formats and supports, high-lighting large format ones using watercolors. These drawings are of great inter-est as they are a project commissioned by the city of Zaragoza in which the proposal included the square and the Basílica del Pilar. All these documents show the work of a not very well known architect, but of undoubted value through his interesting drawings

Integración de entornos virtuales de enseñanza y aprendizaje en la educación universitaria

Este trabajo propone una estrategia de administración de entornos virtuales de enseñanza y aprendizaje para la Dirección de Educación a Distancia y Tecnologías (EaDyT) de la Universidad Nacional de la Plata (UNLP). Se presenta el análisis de la situación actual, basado en un trabajo realizado en el año 2015 a través de encuestas y análisis de los propios datos del entorno Moodle que se utiliza para administrar los cursos virtuales de la Dirección de EaDyT. Se desarrolla un estudio de tecnologías que permitan integrar los entornos virtuales de la Dirección y de la UNLP en general.In this presentation we propose a new administration strategy of the learning management systems in the Dirección de Educación a Distancia y Tecnologías (EaDyT) de la Universidad Nacional de la Plata (UNLP). It presents the analysis of the current situation, based on a completed report in 2015 through surveys and statistics collected from the own Moodle sites used to manage the online courses at the Dirección de EaDyT. It develops a study of the technologies allow to integrate all the learning management systems in both the Dirección de EaDyT and the whole UNLP generally.Dirección de Educación a Distancia, Innovación en el aula y TI