703 research outputs found

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

    Get PDF
    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

    3D hydrodynamic model as a tool for more efficient port management and operations.

    Get PDF
    Ports have been attempting to increase their competitiveness by enhancing their productivity and operate in a more environmentally friendly way. The Port of Seville is located in the Guadalquivir River in the south of Spain and it is the unique Spanish inland port. The estuary has generated and is still generating conflicts of interests. The access channel to the port is being periodically dredged, the natural course has been anthropologically modified several times, original salt marshes have been transformed to grow rice 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. Despite its socio-economic and environmental significance there is a surprising lack of scientific and technical information about the environmental interactions between the port activities and the Guadalquivir estuary stakeholders. A 3D hydrodynamic model has been developed to study the tidal regime, water circulation, temperature and salinity distributions, flooding areas and the sediment dynamics in the estuary. The model output has been validated with in situ current speed, direction, water elevation and also with temperature and salinity measurements. Good agreement between modeled and real measurements have been obtained. Our preliminary results show that the vessel traffic management could be improved by using the tidal elevations and currents calculated by the model in the whole estuary. The interactions among the port activities (mainly due of changes in the sediments dynamics), the watershed management and the saline intrusion evolution will be studied in detail. 3D Hydrodynamic Modelling provide spatially explicit information on the key variables governing the dynamics of estuarine areas. The numerical model is a powerful tool to effectively guide the management and operations of ports located in a complex socio-ecological systems.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Bioqueries: a collaborative environment to create, explore and share SPARQL queries in Life Sciences

    Get PDF
    Bioqueries provides a collaborative environment to create, explore, execute, clone and share SPARQL queries (including Federated Queries). Federated SPARQL queries can retrieve information from more than one data source.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

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

    Get PDF
    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

    Heat fluxes between the Guadalquivir river and the Gulf of Cádiz Continental Shelf

    Get PDF
    An 18-year time series of daily sea surface temperature of Gulf of Cadiz and an 18-month time series of temperature collected in the vicinity of the Guadalquivir estuary mouth have been analyzed to investigate the heat exchange between the estuary and the adjacent continental shelf. The first time identifies a continental shelf area where seasonal thermal oscillation signal (amplitudes and phase) changes abruptly. In order to explain this anomaly, the second data set allows a description of thermal fluctuations in a wide range of frequencies and an estimation of the upstream heat budget of the Guadalquivir estuary. Results show that high frequency thermal signal, diurnal and semidiurnal, and water flux signal through Guadalquivir mouth, mainly semidiurnal, apparently interact randomly to give a small exchange of thermal energy at high frequency. There is no trace, at the estuary's mouth, of daily heat exchanges with intertidal mudflats probably because it tends to cancel on daily time scales. Results also show that fluctuations of estimated air-sea fluxes force fluctuations of temperature in a quite homogeneous estuarine, with a delay of 20 days. The along-channel thermal energy gradient reaches magnitudes of 300-400 J m-4 near the mouth during the summer and winter and drives the estuary-shelf exchange of thermal energy at seasonal scale. Particularly, the thermal heat imported by the estuary from the shelf area during late fall-winter-early spring of 2008/2009 is balanced by the thermal heat that the estuary exports to the shelf area during late spring-summer of 2008. In summary, Guadalquivir river removes/imports excess of thermal energy towards/from the continental shelf seasonally, as a mechanism to accommodate excess of heat from one side respect to the other side.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Autoridad Portuaria de Sevilla (APS

    Physical characterization of the Guadiana Estuary using a 3D model

    Get PDF
    Guadiana estuary is an intertidal estuary situated in SW of Iberian Península, the latest 50 Km of which constitutes the natural border between Spain and Portugal. Tidal influence extends to about 80 Km upstream. The Guadiana River presents a high seasonal irregularity with wet winters and dry summers. A 3D hydrodynamic model based on the MOHID System has been developed to study the hydrodynamics of the Guadiana Estuary. The model has been validated by comparison the output with in situ data measurements in several points along the estuary.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Plant-Derivatives Small Molecules with Antibacterial Activity

    Get PDF
    The vegetal world constitutes the main factory of chemical products, in particular secondary metabolites like phenols, phenolic acids, terpenoids, and alkaloids. Many of these compounds are small molecules with antibacterial activity, although very few are actually in the market as antibiotics for clinical practice or as food preservers. The path from the detection of antibacterial activity in a plant extract to the practical application of the active(s) compound(s) is long, and goes through their identification, purification, in vitro and in vivo analysis of their biological and pharmacological properties, and validation in clinical trials. This review presents an update of the main contributions published on the subject, focusing on the compounds that showed activity against multidrug-resistant relevant bacterial human pathogens, paying attention to their mechanisms of action and synergism with classical antibiotics

    A Resource Extraction Model with Technology Adoption under Time Inconsistent Preferences

    Full text link
    A two-stage non-standard optimal control problem with time inconsistent preferences is studied. In an infinite horizon setting, a time consistent (sophisticated) decision maker chooses the time of switching between two consecutive regimes. The second regime corresponds to the implementation of a new technology, and a cost must be paid at the switching time. Although the problem is formulated for a general discount function, special attention is devoted to models with nonconstant discounting and heterogeneous discounting. The problem is solved by transforming it into a problem in a finite horizon and free terminal time. The corresponding dynamic programming equations are presented, and conditions for the derivation of the switching time by decision makers with different degrees of sophistication are studied. A resource extraction model with technology adoption is solved in detail. Effects of the adoption of different discount functions are illustrated numerically

    Genomas de geminivirus: pequeños pero matones

    Get PDF
    All living organisms possess a genome, constituted by nucleic acid, which encodes the proteins necessary to complete their life cycle and interact with the environment. Without entering into the more or less philosophical disquisition of whether viruses are living organisms or not, what can be affirmed is that life on Earth cannot be imagined without the existence of these “simple” organisms. Viruses possess a genome of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) that is usually encapsulated in a more or less complex protein cover that sometimes contains lipid components. The size of the viral genome varies enormously between species.Todos los organismos vivos poseen un genoma, constituido por ácido nucleico, que codifica las proteínas necesarias para comple- tar su ciclo vital e interaccionar con el medio ambiente. Sin entrar en la disquisición más o menos filosófica de si los virus son o no organismos vivos, lo que sí puede afirmarse es que la vida en la Tierra no puede imaginarse sin la existencia de estos "sencillos" organismos. Los virus poseen un genoma de ácido desoxirribo- nucleico (ADN) o ácido ribonucleico (ARN) que suele encapsidarse en  una  cubierta  proteica más o menos compleja que en ocasiones con- tiene componentes lipídicos. El tamaño del genoma viral varía enormemente entre especies

    La rehabilitación en el deporte

    Get PDF
    Las lesiones deportivas presentan una creciente prevalência, asociada con el aumento de la práctica deportiva. Tanto a niveles de competición como recreacionales, se constata una demanda del deportista para volver a la actividad de la forma más rápida y funcional posible. Se examinan en este trabajo las características de la lesión de aparato locomotor en el deporte, y las peculiaridades del proceso de rehabilitación tras el tratamiento inicial, analizándose los actuales procedimientos e infraestructura empleados para su desarrollo, desde una perspectiva multidisciplinar
    corecore