Universidad de Zaragoza

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    Did language evolve through language change? On language change, language evolution and grammaticalization theory

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    The relation between language change and the process of language evolution is controversial in current linguistic theory. Some authors believe that the two processes are completely unrelated, while for others the evolution of language is (at least in part) a consequence of linguistic changes. Both models imply a very different assessment of what is changing when languages themselves change. I present an explicit model of what changes when languages change, and I show that the claim that language change is a crucial factor in explaining the evolution of human language, although suggestive and very popular, faces problems of a theoretical and empirical nature

    The shallow water equations and their application to realistic cases

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    The numerical modelling of 2D shallow flows in complex geometries involving transient flow and movable boundaries has been a challenge for researchers in recent years. There is a wide range of physical situations of environmental interest, such as flow in open channels and rivers, tsunami and flood modelling, that can be mathematically represented by first-order non-linear systems of partial differential equations, whose derivation involves an assumption of the shallow water type. Shallow water models may include more sophisticated terms when applied to cases of not pure water floods, such as mud/debris floods, produced by landslides. Mud/debris floods are unsteady flow phenomena in which the flow changes rapidly, and the properties of the moving fluid mixture include stop and go mechanisms. The present work reports on a numerical model able to solve the 2D shallow water equations even including bed load transport over erodible bed in realistic situations involving transient flow and movable flow boundaries. The novelty is that it offers accurate and stable results in realistic problems since an appropriate discretization of the governing equations is performed. Furthermore, the present work is focused on the importance of the computational cost. Usually, the main drawback is the high computational effort required for obtaining accurate numerical solutions due to the high number of cells involved in realistic cases. However, the proposed model is able to reduce computer times by orders of magnitude making 2D applications competitive and practical for operational flood prediction. Moreover our results show that high performance code development can take advantage of general purpose and inexpensive Graphical Processing Units, allowing to run almost 100 times faster than old generation codes in some cases

    Monitoring breathing rate by fusing the physiological impact of respiration on video-photoplethysmogram with head movements

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    Objective: The simple observation of breathing rate (BR) remains the first and often the most sensitive marker of acute respiratory dysfunction. In fact, there are evidences that drastic changes in BR are a predictive indicator of adverse events (i.e. cardiac arrest). The aim of this study is to develop a camera-based technology that may provide near-continuously estimation of BR considering the effect of respiration on videoPPG (vPPG). 
 Approach: The technology has been tested in two different experimental settings, including controlled BR and more challenging scenarios with spontaneous breathing pattern. Video data were processed offline to derive the vPPG signal. The method derives respiration from beat-to-beat PPG rate and morphology changes in amplitude and width driven by the physiological relationships between vPPG and respiration. Moreover, respiratory-induced head movements were used as additional source of information for the vPPG system. A combination of these methods has been exploited to estimate the respiratory rate every 10 second. 
 Main Results: According to the results, respiratory frequencies in the central range (0.2-0.4 Hz) may be estimated using vPPG system with low relative error, eR < 2 % and interquartile range of order IQR < 5 %. However, the vPPG system showed a drop in performance at respiratory range boundaries, around 0.1 Hz and 0.5 Hz.
 Significance: This camera-based technology can be used as ubiquitous BR monitoring system. However, vPPG-based systems should consider the effect of the BR in the estimation, mainly in applications where respiratory rate is out of the range 0.2-0.4 Hz

    Student interaction through a PBLL approach: An attempt to place peer interaction at the core of the Teaching/Learning process. “Social Media: Utopia and Dystopia through BlackMirror”

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    AbstractDuring my placement period in La Anunciata, a private with a state funding school in Zaragoza, I attended several ESO lesson from different years. Here, I observed that there was little interaction between students during class activities. Therefore, the main aim of this Dissertation is to design a learning unit that focused on a PBLL in which the activities designed around student interaction are essential in order to advance in the project. This lesson plan is based on several communicative language teaching and cooperative principles. These principles will also be essential for the development of communicative competences. Furthermore, the guidelines provided by the LOMCE Aragonese Curriculum for ESO have been taken into account for the development of this unit.ResumenDurante mi periodo de practicas en el Colegio La Anunciata, un colegio concertado de Zaragoza, asistí a varias clases de diferentes años de la ESO. Durante este periodo, pude observar que la interacción entre alumnos durante las actividades realizadas en clase era escasa. Por tanto, el objetivo de mi trabajo es diseñar una unidad didáctica basada en el método PBLL en el que las actividades estén orientadas a la interacción entre estudiantes y que éstas sean esenciales para el progreso del proyecto. La fundamentación teórica de esta unidad se basa en el Método Comunicativo y en el trabajo cooperativo. Además, se ha llevado a la práctica las recomendaciones propuestas en el Currículo Aragonés de la ESO.<br /

    Slowing down of spin glass correlation length growth: Simulations meet experiments

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    The growth of the spin glass correlation length has been measured as a function of the waiting time tw on a single crystal of CuMn (6 at. %), reaching values ¿~150 nm, larger than any other glassy correlation length measured to date. We find an aging rate dlntw/dln¿ larger than found in previous measurements, which evinces a dynamic slowing down as ¿ grows. Our measured aging rate is compared with simulation results by the Janus Collaboration. After critical effects are taken into account, we find excellent agreement with the Janus data

    Use of internal boundary conditions for levees representation: application to river flood management

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    River floods can be simulated with the 2D shallow water system of equations using finite volume methods, where the terrain is discretized in cells that form the computational mesh. Usually a proper treatment of wet/dry fronts is required. River levees can be modelled as part of the topography by means of sufficiently small cells of higher elevation than the rest of the bed level in locally refined meshes. This procedure is associated with a large computational time since the time step depends directly on the cell size. The alternative proposed in this work includes the levees as internal boundary conditions in the 2D numerical scheme. In particular, levees have been defined by a weir law that, depending on the relative values of water surface levels on both sides, can formulate the discharge for different situations (i.e. free flow and submerged flow). In addition, having identified numerical difficulties in cases of low discharge under free flow conditions, a novel procedure to avoid oscillations has been developed and called volume transport method. The validation and comparison between methods has been carried out with benchmark test cases and, in addition, with a real flood event in the Ebro River (Spain)

    Exergy assessment and exergy cost analysis of a renewable-based and hybrid trigeneration scheme for domestic water and energy supply

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    Exergy and exergy cost analyses are proposed as complementary methods for the assessment and better understanding of the efficiency of a hybrid trigeneration system based on renewable energy sources. The system combines photovoltaic/thermal collectors, an evacuated tube collector and a wind turbine and produces electricity, sanitary hot water and desalted fresh water for a single family house. The system includes two desalination technologies (reverse osmosis and membrane distillation) that consume power and heat respectively, and two kinds of energy storage devices (a hot water tank and two lead-acid batteries). The assessment is based on simulations developed by using TRNSYS software. As a first level of detail, exergy analysis is applied in ten-minute basis to selected plant components. As a second level of detail, it is proposed to apply exergy-based indicators that summarize the system behavior during a longer period of time (monthly basis). By using aggregated values, exergy accumulation terms become negligible, what allows applying symbolic thermoeconomics to calculate exergy cost and to analyze in depth the process of cost formation. The system has an exergy efficiency of 7.76% (6.68 due to electricity, 0.33 due to fresh water and 0.75 due to sanitary hot water)

    Thermodynamic assessment of raw material use in passenger vehicles

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    Conseguir una economía mundial libre de carbono es de vital importancia para evitar el aumento de las temperaturas del planeta y sus fatales consecuencias para la humanidad. Para lograr ese objetivo se están llevando a cabo grandes avances en el desarrollo tanto de energías renovables como de vehículos más limpios. En el caso de los vehículos esos avances se están centrando principalmente en mejorar la eficiencia de los motores combustión, reducir la emisión tanto de gases de efecto invernadero como de otros perjudiciales para la salud y en el desarrollo de vehículos libres de emisiones directas, como los vehículos eléctricos.Estos avances hacía la obtención de automóviles más limpios está provocando un cambio en la actual flota de vehículos y se espera que en las próximas décadas habrá una renovación total de la misma. La nueva generación de vehículos reducirá en gran parte su dependencia con relación a los combustibles fósiles, sin embargo a cambio demandará una gran cantidad de recursos naturales, tan valiosos e incluso más escasos en ocasiones que el petróleo. Algunos de estos recursos serán: Co, Ni, Mn o Li para fabricar baterías; Ga, Ge, Y para hacer sistemas de iluminación tipo LEDs; Nd, Dy, Pr para construir imanes permanentes de motores eléctricos; Pt, Pd, Zr para hacer catalizadores que reduzcan la contaminación; Au, Ag, Sn, Ta, Yb para fabricar unidades electrónica; Ce, Tb, Se, La para hacer sensores o Nb, Mo, Cr, Ti, V, Sc, W para hacer aleaciones de acero de alta resistencia. Lamentablemente, estos recursos son finitos y algunos de ellos incluso ya son considerados como críticos por la Comisión Europea y otras institucionesinternacionales.Una de las soluciones para mejorar la sostenibilidad en la fabricación de vehículos desde el puntode vista de los materiales que se emplean es el reciclaje. Sin embargo hay dos grandes problemas en torno al mismo. Por un lado los ratios de reciclaje no están avanzando tan rápidamente como la demanda de materiales y por otro lado las políticas de reciclaje no incentivan la recuperación de metales escasos. En la actualidad, los objetivos de reciclaje de vehículos se fijan en alcanzar un porcentaje de reciclabilidad sobre la masa total del vehículo. Para conseguir esas cuotas de reciclaje se llevan a cabo convencionalmente procesos mecánicos de separación de materiales.Estos procesos son de baja intensidad energética y a la vez muy eficaces para recuperar los metales que se emplean en mayores cantidades (acero, aluminio o cobre) pero resultan ineficaces para recuperar metales empleados en pequeñas proporciones (metales críticos o escasos). Como consecuencia, los metales críticos terminan subciclados en los procesos de fabricación de aleaciones de acero o aluminio y en el peor de los casos dispersos en un vertedero.Esta tesis se desarrolla con el objetivo principal de mejorar la eficiencia en el uso de los recursos necesarios para la fabricación de automóviles. Para conseguir dicho propósito se presenta una metodología que mide la eficiencia en el uso de los recursos e identifica posibles restricciones de suministro de metales.La metodología desarrollada se basa en la aplicación de la segunda ley termodinámica y el concepto de rareza termodinámica. Este enfoque cuantifica el valor real físico de todos los metales empleados y destaca en especial la aportación de aquellos cuya contribución al peso total del vehículo es pequeña, pero cuya escasez y por tanto su valor para el planeta es elevada. Este método evalúa la calidad de los materiales en función de su abundancia en la naturaleza y la energía útil (exergía) requerida tanto para extraerlos como para procesarlos y ponerlos a disposición de las industrias.Además del enfoque termodinámico, en esta Tesis se analizan las posibles restricciones de metales que puedan surgir en las próximas décadas. Para ello se aplica un modelo que considera la disponibilidad geológica de materiales (reservas y recursos), la capacidad de producción anual de los metales, la demanda anual estimada de cada metal, la demanda acumulada hasta 2050, la evolución de las cuotas de reciclaje y el impacto de la demanda de materiales de otros sectores.Los métodos desarrollados se aplican a diferentes tipos de vehículos (ICEV1, PHEV2 y BEV3) y han permitido alcanzar entre otros los siguientes resultados principales: (1) Desde el punto de vista del valor mineral de los recursos empleados, un vehículo eléctrico demanda 2.2 veces más recursos que un vehículo de combustión; (2) Hay 31componentes críticos en un vehículo convencional desde la perspectiva de los materiales que emplean; (3) Se han definido recomendaciones de ecodiseño para esos componentes basadas en reducir la demanda de metales escasos y mejorar tanto su reciclabilidad como su reusabilidad; (4) En los actuales procesos de reciclaje de vehículos un 27 % del valor mineral de los metales no se recicla funcionalmente; (5) Se han propuesto recomendaciones para la reducción de dichas pérdidas; (6) Se ha definido un ranking de los metales más estratégicos para el sector de la fabricación de vehículos siendo los 10 más estratégicos los siguientes: Ni, Li, Tb, Co, Dy, Sb, Nd, Pt, Au y Ag.Las contribuciones de esta Tesis son de gran valor para mejorar la sostenibilidad del sector de la fabricación de vehículos desde la perspectiva de los materiales que se emplean y están principalmente dirigidas a los siguientes grupos de interés: (1) Los diseñadores de vehículos, porque les ayudará a identificar propuestas de ecodiseño desde la perspectiva de los materiales; (2) Los responsables de desarrollar políticas en torno a la eficiencia en el uso de los recursos, ya que demuestra la debilidad de las políticas actuales basadas en el peso de los materiales y ofrece como alternativa un método que evalúa tanto la cantidad como la calidad de los materiales; (3)Los ejecutivos de las empresas, porque les presenta la dependencia y vulnerabilidad de la tecnología sobre ciertos materiales y les ayudará a planificar con antelación líneas de I+D+ibasadas en la eficiencia en el uso de los recursos.Decarbonizing world economies is necessary to avoid the continuous increase of global temperature and its negative consequences for humanity. To get this ambitious target new advances in the fields of power generation with renewables and mobility with cleaner vehicles are being made. In the case of vehicles, these advances are being mainly focused on improving the performance of combustion engines, to reduce greenhouse and polluting emissions and the development of free direct emission vehicles like the electric ones. Advances towards cleaner vehicles are encouraging the continuous renovation of vehicle fleet so it is expected that in the following decades a complete renovation will take place. This new generation of vehicles will significantly reduce its fossil dependency. But in contrast, it will demand a huge quantity of other kinds of natural resources being some of them even scarcer than oil. Some of these resources will be necessary to manufacture the following components: batteries (Co, Ni, Mn or Li); LEDs for lighting (Ga, Ge, Y); permanent magnets for motors (Nd, Dy, Pr); catalytic converters (Pt, Pd, Zr); electronic units (Au, Ag, Sn, Ta, Yb), different kinds of sensors (Ce, Tb, Se, La), infotainment screens (In); automotive high performance steel or aluminum alloys (Nb, Mo, Cr, Ti, V, Sc, W) or injectors (Tb). Unfortunately these resources are finite and some of them are very scarce being even considered as critical for the European Commission and other institutions from several perspectives such as vulnerability, economic importance, supply, or ecological risks. One of the solutions to improve resource efficiency in vehicles is to recycle these valuable metals. Nevertheless, there are two main problems around the recycling situation. On one hand, recycling rates are not growing up as faster as metal demand. On the other hand, current recycling policies define targets based on mass weight approaches, and even if they are ambitious, they fail in enhancing the recycling of minor but critical metals. The legislation compliance is achieved by means of applying mechanical separation techniques. These processes are effective to recycle those metals with the highest contribution in the vehicle weight (steel, aluminum and copper) but they are not effective for the recovery of minor metals like those that are scarce and/or critical. Consequently, minor metals end downcycled during steel or aluminum smelting or in the worst case they finish dispersed in landfills. This Thesis is presented with the main aim to improve the resource efficiency in the vehicle manufacturing sector. To accomplish with this aim, a novel method for measuring the resource efficiency and to identify possible shortages in the supply of metals is presented. The resource efficiency is analyzed through the second law of Thermodynamics through the concept of thermodynamic rarity. This method takes into account the quality of mineral commodities as a function of their relative abundance in Nature and the energy intensity required to extract and process them. The application of the thermodynamic approach allows not only to recognize the physical value of materials with a low weight contribution but also to identify those components that use them. As it has been mentioned before this Thesis also assesses possible metal shortages. This activity is made by means of an own method which combines geological data (reserves and resources), annual capacity production, annual expected demand, cumulative expected demand to 2050, recycling rates evolutions and future resource demand of other technologies. The methodology is applied to different types of vehicles (ICEV , PHEV and BEV ) and it has been useful to achieve the following main results: (1) From a thermodynamic point of view an electric vehicle demands 2.2 times more quality resources than a combustion one; (2) 31 critical components were identified in a conventional vehicle from the perspective of the materials used to manufacture them; (3) Eco-design recommendations for these components have been defined. These recommendations are based on: reducing the demand of scarce metals and to increase both the recyclability and the reusability; (4) In current End of Life Vehicle (ELV) processes 27 % of the mineral capital (measured in rarity terms) is not functionally recycled; (5) Recommendations to reduce these losses have been proposed; (6) A strategic metal ranking for the automobile sector has been produced, being the top 10 most strategic metals the following: Ni, Li, Tb, Co, Dy, Sb, Nd, Pt, Au and Ag. The contributions of this Thesis are valuable to improve the sustainability of the vehicle manufacturing sector from the raw materials point of view. These contributions are mainly valuable for the following stakeholders: (1) Designers because it helps them to apply eco-design proposals from a raw materials point of view; (2) Policy makers because it evidences the weakness of mass based approach recycling policies and it proposes an alternative method that takes into considerations not only quantity but also quality; (3) Company’s executives because it confronts them with the metal dependency and vulnerability of technology and it helps them to plan with enough time R+D+i lines based on resource efficiency.<br /

    Early life risk factors and their cumulative effects as predictors of overweight in Spanish children

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    Objectives: To explore early life risk factors of overweight/obesity at age 6 years and their cumulative effects on overweight/obesity at ages 2, 4 and 6 years. Methods: Altogether 1031 Spanish children were evaluated at birth and during a 6-year follow-up. Early life risk factors included: parental overweight/obesity, parental origin/ethnicity, maternal smoking during pregnancy, gestational weight gain, gestational age, birth weight, caesarean section, breastfeeding practices and rapid infant weight gain collected via hospital records. Cumulative effects were assessed by adding up those early risk factors that significantly increased the risk of overweight/obesity. We conducted binary logistic regression models. Results: Rapid infant weight gain (OR 2.29, 99% CI 1.54–3.42), maternal overweight/obesity (OR 1.93, 99% CI 1.27–2.92), paternal overweight/obesity (OR 2.17, 99% CI 1.44–3.28), Latin American/Roma origin (OR 3.20, 99% CI 1.60–6.39) and smoking during pregnancy (OR 1.61, 99% CI 1.01–2.59) remained significant after adjusting for confounders. A higher number of early life risk factors accumulated was associated with overweight/obesity at age 6 years but not at age 2 and 4 years. Conclusions: Rapid infant weight gain, parental overweight/obesity, maternal smoking and origin/ethnicity predict childhood overweight/obesity and present cumulative effects. Monitoring children with rapid weight gain and supporting a healthy parental weight are important for childhood obesity prevention


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