8,917 research outputs found

    Modeling changes in the tidal propagation and its implication for vessel navigation in Guadalquivir estuary ( Spain)

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    The Port of Seville is an inland harbour located in the Guadalquivir Estuary some 80 km from the river mouth and is the unique Spanish inland port. Vessel traffic in the estuary is a relevant economic activity and a suitable trade-off between vessel draught and safety to prevent ship aground is required and to optimize the port operability. The Guadalquivir is a mesotidal estuary with tidal range of 2-3 m, an important fraction of the minimum depth of the navigation waterway (presently 6.5m). Upstream navigation is favoured around high water as the tide progresses at 12 knots, which is comparable to the vessel speed, thus allowing greater vessel draughts. Oceanwards navigation of heavy vessels, on the contrary, is hampered by the tide because a low water is unavoidably met when heading downstream. A 3D, high resolution hydrodynamic model has been implemented in the whole estuary to study the tidal propagation. The model is forced by the oceanic tide at the mouth and freshwater discharges controlled by an upstream dam at the head. It has been satisfactorily validated and predicts tidal oscillations with high accuracy (less than 4 cm in amplitude and 20 min in phase everywhere in the estuary). Based on the model outputs of tidal heights and currents and using present-day estuary bathymetry, a MATLAB application has been developed for shipping planning (Vessel Traffic Decision Support System, VTDSS). The application allows the final users to test different traffic scheduling scenarios in order to assess the effects on navigational patterns and explore possible management and policy scenarios under sea level rise and changes in tidal propagation. A description of the model and an overview of the VTDSS are presented here; the effectiveness as a decision support tool is demonstrated via the simulated navigation time of several vessels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Autoridad Portuaria de Sevill

    Income, Mortality, and Literacy Distribution Dynamics Across States in Mexico: 1940-2000

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    This paper analyzes the dynamics of the distributions of per capita Gross Domestic Product (GDP), the infant mortality rate, and the adult literacy rate across states in Mexico between 1994 and 2000. It analyzes the hypothesis of convergence to a common lConvergence, distribution dynamics, markov chain, kernel densities, transition matrix, panel data, Mexico

    Vinylic Addition Polynorbornene in Catalysis

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    Vinylic addition polynorbornenes (VA-PNB) result from the insertion polymerization of norbornene or specific norbornene derivatives catalyzed by transition metal com- plexes. The VA-PNB skeleton is completely aliphatic and keeps the bicyclic structure of norbornene. This saturated polymer is thermally and chemically very stable and it is a very robust scaffold to support catalysts or reagents for catalytic applications. Several VA-PNBs are now available with suitable functional groups (halogen, alkenyl, carbonates) that can be used as starting materials to introduce the functionalization of choice by post-polymerization reactions. This has been applied to anchor organocatalysts on VA-PNB as well as ligands that can be used to synthesize supported metal catalysts. The reported examples of the use of VA-PNB-linked catalysts and their recyclability will be presented. VA-PNBs have also proved useful in the context of organotin chemistry to solve the problem of tin contamination by an efficient separation and the reuse of tin byproducts. Its uses in the Stille cross-coupling reaction and tin-hydride radical proc- esses will be discussed.MINECO (SGPI, grant CTQ2016-80913-P)Junta de Castilla y León (grants VA062G18 and VA051P17 and a fellowship to RGL

    Hydrodynamic changes in Guadalquivir estuary (Spain) due to a hypothetical tidal marsh restoration project

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    Tidal marsh restoration will be an important management issue in Guadalquivir Estuary in the near future. The Guadalquivir Estuary has been anthropologically modified several times, the river is bounded by embankments to protect rice and cotton plantations from tidal inundation, the meanders have been transformed into straight sections, about 80 % of the original marsh surface has been lost and approximately one-fourth of the total surface of the estuary is now part of two protected areas, one of them is a UNESCO, MAB Biosphere Reserve. A hypothetical restoration of tidal marshes will benefits different species and functions based on location, elevation, adjacent habitats, degree of hydrodynamic connectivity and would reduce the present high levels of turbidity. The restoration projects should be accompanied by studies for a better understanding of the environmental changes expected. A Large-scale construction of tidal marsh will change tidal dynamics, modify the tidal inundation regime and the freshwater flow over the surrounding areas. A hydrodynamic model has been developed to study changes in the tidal propagation and the flow regime due to a hypothetical marsh restoration. The model has been calibrated and the output has been validated with in situ water elevation and good agreement between modelled and real measurements have been obtained. A sensitivity test changing the size, locations from the estuary mouth and depth has been carried out to highlights impacts over the tidal propagation, flow regime, salinity intrusion and the tidal inundation regime. Our preliminary results show that the tidal elevation and the current speed will be considerably affected in the estuary. The model open the possibility to study interactions among the tidal marsh restoration project, Seville port operations, fisheries and agricultural activities. The numerical model will be a powerful tool in restoration projects in a complex socio-ecological system.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Autoridad Portuaria de Sevill

    Creatividad y nuevas tecnologías: Las claves de la cultura emprendedora. El papel de la universidad en la formación de intelectuales con espíritu emprendedor

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    Vivimos en una sociedad azotada por una fuerte depresión económica y, lo que es más preocupante, una crisis de ideas y valores. Las respuestas tomadas desde los poderes públicos a esta situación, como recortes o contención, no han servido para resolver los problemas sino para poner en jaque la idea de un estado del bienestar, de naturaleza social, que trata de mitigar las desigualdades entre sus ciudadanos. Precisamente por este motivo se hace necesario buscar una solución más compleja y a largo plazo. Una estrategia que apueste de forma decidida y sin complejos por la educación, la investigación y la creatividad como ejes vertebradores de las diferentes políticas de recuperación. Una nueva universidad que tenga como fin principal formar ciudadanos con competencias intra e interpersonales, partícipes de una cultura emprendedora que permita dar respuestas a los problemas actuales y a los nuevos que se presentarán en el futuro. Nuevos modelos que generen ideas creativas e innovadoras encaminadas a la creación de empleo de calidad, incrementen el bienestar de los ciudadanos, ampliando sus espacios de participación activa, de comunicación y expresión, y construyendo una sociedad más equilibrada, presidida por la idea de justicia social, donde cobren importancia los valores del compromiso emocional, racional y ético, y que gestione la diversidad como una fuente de riqueza.We live in a society plagued by a severe economic depression and, more worryingly, a crisis of ideas and values. Answers taken from the public authorities to this situation, as cuts or containment, have failed to solve the problems but to jeopardize the idea of a welfare state, social nature, which seeks to mitigate inequalities among its citizens. Precisely for this reason it is necessary to seek a more complex and long-term solution. A strategy to bet decisively without complex for education, research and creativity as backbones of the different recovery policies. A new university that has as main purpose to educate citizens intra and interpersonal skills, participants in an entrepreneurial culture that allows to respond to current and new problems that arise in the future. New models that generate creative and innovative aimed at creating quality employment ideas, increase the welfare of citizens, expanding their areas of active participation, communication and expression, and building a more balanced society, dominated by the idea of social justice where gain importance values emotional, rational and ethical commitment, and to manage diversity as a source of wealth

    Publicidade digital, storytelling e transmedia narrativa: educomunicação do consumidor

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    The present text tries to analyze the relationships between the concept of digital storytelling applied to advertising starting from the base of the transmedia narrative. This is: how the new transmediatic narrative helps the construction of advertising discourses based on the notion of storytelling and how it establishes the bases for an educommunication of the consumer, the spectator and / or the target.El presente texto trata de analizar las relaciones entre el concepto de storytelling digital aplicado a la publicidad partiendo de la base de la narrativa transmedia. Esto es: cómo la nueva narrativa transmediática ayuda a la construcción de discursos publicitarios basados en la noción de storytelling y cómo ello establece las bases para una educomunicación del consumidor, del espectador y/o del target.O presente texto tenta analisar as relações entre o conceito de narrativa digital aplicado à publicidade a partir da base da narrativa transmedia. Isto é: como a nova narrativa transmediaica ajuda a construção de discursos publicitários com base na noção de narrativa e como estabelece as bases para uma educação do consumidor, o espectador e / ou o target

    Bitcoin, ¿una criptodivisa rentable?

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    Nos encontramos en un mundo donde los cambios y los avances tecnológicos son una constante, y uno de los últimos fenómenos que se ha producido ha sido el surgimiento de Bitcoin, una criptodivisa o moneda electrónica. En el presente trabajo vamos a tratar de explicar algunos aspectos de este fenómeno, su naturaleza y, finalmente, trataremos de determinar si se trata de una inversión rentable. Bitcoin se utiliza, por un lado, igual que cualquier otra moneda, para intercambiar bienes y servicios, si bien se caracteriza por una serie de elementos que la hacen única y distinta al resto de divisas. Y, por otro lado, es utilizada también como commodity, como veremos a lo largo del trabajo. Tiene origen durante la crisis económica y financiera del año 2008, donde el entramado financiero se vino abajo, contemplando muchos clientes de las sociedades bancarias y financieras cómo sus ahorros, sus inversiones… se desplomaban sin poder hacer nada, siendo uno de los motivos que ha propiciado su expansión, su autonomía, por no depender de ninguna autoridad central que lo controle o gestione

    Bank Lending Channel and the Monetary Transmission Mechanism: the Case of Chile

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    This paper analyses the evidence about the bank-lending channel in Chile during the period 1990- 2002 using data from both the banking sector and the corporate sector. First, we estimate a panel data of banks to identify shifts in the loan supply curve in response to changes in monetary policy. Second, taking into consideration the evidence gathered in the previous step, we construct an aggregate variable aimed to capture the main forces behind the bank lending channel, and we estimate a VAR system to test whether or not this channel exacerbates the effect of a monetary policy shock over macroeconomic activity. We conclude that the bank-lending channel has operated as a monetary policy transmission mechanism in Chile during the sample period, having an independent and significant effect in terms of macroeconomic activity.
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