Evolución paramétrica del sistema de Lorenz

En esta comunicación se estudia el comportamiento del sistema clásico de Lorenz en función de los tres par´ametros adimensionales del sistema utilizando indicadores de caos

SIMULACIÓN DE UN RECUPERADOR DE CALOR PARA GASES DE ESCAPE BASADO EN MATERIALES TERMOELÉCTRICOS

EL OBJETIVO DE ESTE TRABAJO ES ANALIZAR UN RECUPERADOR DE CALOR DE LOS GASES DE ESCAPE DE UN AUTOMÓVIL BASADO EN MATERIALES. LA MISIÓN DE DICHO TRABAJO ES PRODUCIR ELECTRICIDAD QUE SUSTITUYA (AL MENOS PARCIALMENTE) AL ALTERNADOR DEL VEHÍCULO, AUMENTANDO LA EFICIENCIA DEL MISMO. EL ESTUDIO INCLUYE REVISIÓN BIBLIOGRÁFICA DE EXPERIENCIAS PREVIAS DE ESTA TECNOLOGÍA Y EL DESARROLLO DE UN MODELO DE DICHO RECUPERADOR

Tribunal de Cuentas y órganos externos de control de las CCAA: Especial referencia a la Cámara de Cuentas de Aragón

Los estados democráticos actuales se caracterizan por una gran intervención en el sistema económico. Para ello, el sector público hace uso de los caudales públicos que se obtienen a través de las contribuciones de los ciudadanos. El control en la gestión de estos caudales es un elemento primordial en la transparencia de los Estados. Este trabajo pretende estudiar el control externo de la actividad económico-financiera llevada a cabo por el Tribunal de Cuentas y los órganos de control externo autonómicos (OCEx), realizando una especial referencia a la Cámara de Cuentas de Aragón como órgano de control externo de la actividad económico-financiera aragonesa.<br /

"Guest editorial": Overtourism and the sharing economy – tourism cities at a crossroads

The tourism industry is fiercely competitive at all levels. While the sector has witnessed a considerable number of new destinations emerge and bid for a share of the market, established and arguably more mature destinations compete to consolidate existing markets and develop new ones. Tourism companies are also facing the arrival of new competitors from other industries. However, this evolving pattern is as applicable to the offer as it is to the demand side of the spectrum. In today’s globalised world, tourists have an international range of choices when it comes to tourism destinations and tour operators. It is against this highly competitive backdrop that the concept of the sharing economy has arrived, initially as a philosophical alternative to more mainstream travel and hospitality options and, more recently, as a convenient - and even personalised - choice in the search for more authentic experiences by tourists with a wide range of disposable incomes (Paulauskaite et al., 2017). This breakthrough innovation has changed the tourism ecosystem as well as tourism destinations at all levels. New players have arrived, redefining relationships among stakeholders and creating new impacts in tourism cities or exacerbating existing ones, including the contested phenomenon of overtourism (see, for instance Koens et al., 2018; or Szromek et al., 2019, among others). Examples of these newcomers can be found in online platforms that range from accommodation (e.g. Airbnb, HomeAway, CouchSurfing) to transport (e.g. Uber, BlaBlaCar), and also include customer reviews (e.g. TripAdvisor), general information (e.g. Wikipedia, Wikitravel), travel guiding (e.g. Tours by Locals) and food & beverage (e.g. EatWith), among others. In fact, the advent of the sharing economy has had a profound impact on the hospitality and tourism ecosystem over the last decade, affecting almost every single one of its components (Almeida-Santana and Moreno-Gil, 2017). The rapid development of the sharing economy and particularly some of its more negative impacts have led to a number of global tourism destinations taking measures to regulate it and, in some cases, limit it considerably. These have included Barcelona (Spain), where local government stopped issuing new licenses for short-term rental accommodation nearly three years ago (Burgen, 2017). Since then, key tourism destinations globally have sought to limit the expansion of Airbnb and other short-term accommodation service platforms (Guttentag, 2018). In Europe global tourism cities such as Krakow, Amsterdam, Berlin, Paris and Vienna, among others, have also sought help from the European Union to tighten up existing regulatory frameworks in this respect (Henley, 2019). However, this reaction by tourism cities is not limited to the accommodation sector. London, for instance, revoked Uber’s license to operate as a private transport provider in November 2019 as a result of irregularities found in its service provision – a decision that is currently subject to appeal by Uber (Topham, 2019). One of the issues this situation inevitably raises is the extent to which the initial ethical principles of the sharing economy have evolved over time and what role can operators such as Fairbnb play in today’s sharing economy spectrum of services and operators (Petruzzi et al., 2019)

A Compact raster lensless microscope based on a microdisplay

Lensless microscopy requires the simplest possible configuration, as it uses only a light source, the sample and an image sensor. The smallest practical microscope is demonstrated here. In contrast to standard lensless microscopy, the object is located near the lighting source. Raster optical microscopy is applied by using a single-pixel detector and a microdisplay. Maximum resolution relies on reduced LED size and the position of the sample respect the microdisplay. Contrarily to other sort of digital lensless holographic microscopes, light backpropagation is not required to reconstruct the images of the sample. In a mm-high microscope, resolutions down to 800 nm have been demonstrated even when measuring with detectors as large as 138 μm × 138 μm, with field of view given by the display size. Dedicated technology would shorten measuring time

Microgrids Power Quality Enhancement Using Model Predictive Control

In electric power systems, any deviation with respect to the theoretical sinusoidal waveform is considered to be a disturbance in the power quality of the electrical grid. The deviation can alter any of the parameters of the waveform: frequency, amplitude, and symmetry among phases. Microgrid, as a part of the electric power system, has to contribute providing an adequate current waveform in grid connected-mode, as well as to guarantee similar voltage features than the standard requirement given for public distribution grids under normal exploitation conditions in islanded mode. Adequate power quality supply is necessary for the correct compatibility between all the devices connected to the same grid. In this paper, the power quality of microgrids is managed using a Model Predictive Control (MPC) methodology which regulates the power converters of the microgrids in order to achieve the requirements. The control algorithm is developed for the following microgrids working modes: grid-connected, islanded, and interconnected. The simulation results demonstrate that the proposed methodology improves the transient response in comparison with classical methods in all the working modes, minimizing the harmonic content in the current and the voltage even with the presence of non-balanced and non-harmonic-free three-phase voltage and current systems

La investigación sobre la imagen de los alojamientos turísticos y las dimensiones que la componen: situación actual y retos de futuro

The present essay review or review paper is oriented to give the readers with an allpervading explanation revolving around the problem of image and its dissociation from branding or the branding process. Based on the hospitality industry (or lodging product) our approach has two significant aspects. On one hand, there is an urgent need of introducing emergent and fresh qualitative studies which complement the open answers regarding the role of knowledge in the purchasing process. On another, no less true is that each product is enrooted into a temporal matrix, in which case the evolution of the branding process seems to be a point of discussion which be brought into the foreground by the side of marketing analysts. Still further, our argument emphasizes on the crucial role of face-to-face interaction as a relational platform to position hotel-related products. This evinces that tourism and hospitality industries are leading towards an inevitable fragmentation which merits to be discussed and scrutinized. &nbsp;El presente ensayo o pieza de revisión es un intento de brindar al lector una lectura holística del problema de la imagen y su disociación respecto a la marca o proceso de construcción de marca. Centrados en la industria hotelera (producto alojativo), la propuesta sugiere dos asuntos significativos. Por un lado, existe una necesidad de introducir nuevos estudios cualitativos que complementen los puntos que no tienen respuesta sobre el rol que juega el conocimiento como aspecto de intención de compra. Por el otro, cada producto se encuentra inserto en una matriz de tiempo, en cuyo caso, estudiar la evolución de la imagen a lo largo de la vida del producto se hace una cuestión de importancia para los analistas de marketing. Así mismo, el ensayo hace énfasis en la interacción microsocial (cara a cara) como forma relacional para el posicionamiento de los productos hoteleros.&nbsp;Ello demuestra que existe una tendencia hacia la fragmentación (segmentación) que debe ser discutida y analizada

Molecular stratigraphic analysis with Raman spectroscopy of the shell of a mussel

Two different cristallographical forms of calcium carbonate (aragonite and calcite) has been identified in mussels with Raman spectroscopy.Peer ReviewedPostprint (published version

Análisis no destructivo de obras de arte con espectroscopia Raman

Peer Reviewe

Difusão de pesquisa científica do turismo em Portugal

Considerando la creciente importancia del turismo en Portugal y el papel protagonista que desempeña este sector en su economía, es notoria la necesidad de analizar la investigación turística que los investigadores e instituciones de este país realizan en el ámbito turístico. El presente artículo analiza la contribución realizada por aquellos investigadores afiliados a instituciones portuguesas en revistas académicas especializadas en turismo, tanto de ámbito nacional, como internacional. El análisis permite identificar aquellas instituciones y autores que han realizado un mayor esfuerzo de investigación y difusión en turismo. El artículo presenta no sólo un ranking de instituciones y autores, sino que también analiza el ámbito geográfico de la aplicación de las investigaciones, el número de coautores medio por trabajo, el número de citas, las revistas en las que publican más activamente sus trabajos y la evolución temporal (2006-2011) del resultado obtenido en la investigación turística. Finalmente, se establecen una serie de conclusiones en relación a la situación actual de la investigación en turismo en Portugal.Considerando a crescente importância do turismo em Portugal e o papel central que esse setor desempenha na economia, é evidente a necessidade de analisar os pesquisadores de turismo e instituições de pesquisa no país feito no turismo. Este artigo analisa a contribuição desses pesquisadores afiliados a instituições portuguesas em revistas acadêmicas em turismo, tanto nacional como internacionalmente. A análise identifica as instituições e autores que fizeram maiores esforços na investigação e divulgação do turismo. O trabalho apresenta não só um ranking de instituições e autores, mas também analisa o âmbito geográfico da aplicação da pesquisa, o número médio de coautores para o trabalho, o número de citações, as revistas que publicam o seu trabalho de forma mais ativa e tendências temporais (2006-2011) do resultado obtido em pesquisa em turismo. Finalmente, uma série de conclusões são tiradas sobre o estado atual da investigação no sector do turismo em Portugal.Tourism is a key industry in Portugal, representing this country an important role in the international market. Thus, there is a need to analyze the tourism research developed by authors and institutions of this country. This paper analyzes the contribution in tourism academic journals (national and international) of those researchers of Portuguese institutions. The paper allows for identifying those institutions and researchers that has shown a higher performance in researching and publishing their studies in tourism. The paper shows a ranking of institutions and authors, but also the geographic application of the studies, number of co-authors, journals where they publish, citations of their papers, etc., considering the dynamic evolution in the period 2006-2011. Finally, the paper highlights some conclusions and recommendations about the current situation of tourism research in Portugal