356 research outputs found
Transposiciones simbólicas de la realidad : El símbolo
Este texto desea explicar por medio de una indagación, la programación e introducción al término: Intervención In –Situ, producto de la propuesta final desarrollada a lo largo de todo el proceso de ejecución. Considerando de especial interés la relación del ser humano con la naturaleza que se dan en este tipo de actividades, fuera de los museos y galerías, también es importante resaltar los diferentes elementos que conforman el tema. Dando al lector una mayor comprensión y entendimiento de estos procesos que también fueron adaptados a la representación desde la pintura, libro arte, fotografía y práctica pedagógica, donde se pudo ver de una manera más amplia la creación artística y no solo limitada a determinadas técnicas ya establecidas en los procesos académicos de las artes visuales. Con este fin se realizó un programa de desarrollo de actividades, donde paso a paso se muestran los avances y la práctica de la intervención en un espacio de la facultad de artes y humanidades de la Universidad Tecnología de Pereira
The land–sea coastal border: a quantitative definition by considering the wind and wave conditions in a wave-dominated, micro-tidal environment
A quantitative definition for the land–sea (coastal) transitional area is proposed here for wave-driven areas, based on the variability and isotropy of met-ocean processes. Wind velocity and significant wave height fields are examined for geostatistical anisotropy along four cross-shore transects on the Catalan coast (north-western Mediterranean), illustrating a case of significant changes along the shelf. The variation in the geostatistical anisotropy as a function of distance from the coast and water depth has been analysed through heat maps and scatter plots. The results show how the anisotropy of wind velocity and significant wave height decrease towards the offshore region, suggesting an objective definition for the coastal fringe width. The more viable estimator turns out to be the distance at which the significant wave height anisotropy is equal to the 90th percentile of variance in the anisotropies within a 100 km distance from the coast. Such a definition, when applied to the Spanish Mediterranean coast, determines a fringe width of 2–4 km. Regarding the probabilistic characterization, the inverse of wind velocity anisotropy can be fitted to a log-normal distribution function, while the significant wave height anisotropy can be fitted to a log-logistic distribution function. The joint probability structure of the two anisotropies can be best described by a Gaussian copula, where the dependence parameter denotes a mild to moderate dependence between both anisotropies, reflecting a certain decoupling between wind velocity and significant wave height near the coast. This wind–wave dependence remains stronger in the central baylike part of the study area, where the wave field is being more actively generated by the overlaying wind. Such a pattern controls the spatial variation in the coastal fringe width.Peer ReviewedPostprint (published version
Managing coastal environments under climate change: pathways to adaptation
This paper deals with the question of how to manage vulnerable coastal systems so as to make them sustainable under present and future climates. This is interpreted in terms of the coastal functionality, mainly natural services and support for socio-economic activities. From here we discuss how to adapt for long term trends and for short terms episodic events using the DPSIR framework.
The analysis is presented for coastal archetypes from Spain, Ireland and Romania, sweeping a range of meteo-oceanographic and socio-economic pressures, resulting in a wide range of fluxes among them those related to sediment. The analysis emphasizes the variables that provide a higher level of robustness. That means mean sea level for physical factors and population density for human factors. For each of the studied cases high and low sustainability practices, based on stakeholders preferences, are considered and discussed. This allows proposing alternatives and carrying out an integrated assessment in the last section of the paper. This assessment permits building a sequence of interventions called adaptation pathway that enhances the natural resilience of the studied coastal systems and therefore increases their sustainability under present and future conditions.Peer ReviewedPostprint (author's final draft
Multivariate statistical modelling of future marine storms
Extreme events, such as wave-storms, need to be characterized for coastal infrastructure design purposes. Such description should contain information on both the univariate behaviour and the joint-dependence of storm-variables. These two aspects have been here addressed through generalized Pareto distributions and hierarchical Archimedean copulas. A non-stationary model has been used to highlight the relationship between these extreme events and non-stationary climate. It has been applied to a Representative Concentration Pathway 8.5 Climate-Change scenario, for a fetch-limited environment (Catalan Coast). In the non-stationary model, all considered variables decrease in time, except for storm-duration at the northern part of the Catalan Coast. The joint distribution of storm variables presents cyclical fluctuations, with a stronger influence of climate dynamics than of climate itself.Peer ReviewedPostprint (author's final draft
A multivariate statistical model of extreme events: an application to the Catalan coast
Wave extreme events can be understood as the combination of Storm-intensity, Directionality and Intra-time distribution. However, the dependence structure among these factors is still unclear. A methodology has been developed to model wave-storms whose components are linked together. The model is composed by three parts: an intensity module, a wave directionality module, and an intra-time distribution module. In the Storm-intensity sub-model, generalized Pareto distributions and hierarchical Archimedean copulas have been used to characterize the storm energy, unitary energy, peak wave-period and duration. In the Directionality and Intra-time sub-models, the wave direction (at the peak of the storm) and the storm growth–decay rates are linked to the variables from the intensity model, respectively. The model is applied to the Catalan coast (NW Mediterranean). The outcomes denote spatial patterns that coincide with the state of knowledge. The proposed methodology is able to provide boundary conditions for wave and near-shore studies, saving computational time and establishing the dependence of the proposed variables. Such synthetic storms reproduce the inter-variable co-dependence of the original data.Peer ReviewedPostprint (published version
Green measures for Mediterranean harbours under a changing climate
Harbour operability may be hampered by climate change. Green solutions can be used to provide extra flexibility with respect to present grey infrastructure to adapt to, and mitigate, such functional disruptions with affordable costs. This paper assesses the performance of a green solution (a seagrass meadow) by assessing its effectiveness through numerical modelling. The analysis is carried out at two harbours that, under the present climate, are prone to wave agitation and overtopping problems. The efficiencies of different seagrass layouts are tested at both sites, by comparing the relevant hydrodynamic parameters. It is concluded that, for moderate sea level rise (SLR) rates, illustrated by the central trend of a medium scenario from the Intergovernmental Panel on Climate Change, the use of seagrass meadows would be effective enough to attenuate the impact of SLR on breakwater overtopping. In addition, the use of such measures could attenuate the increases in port agitation due to changes in wave direction caused by climate change. Nevertheless, the complexity of the interactions between hydrodynamics and seagrass would require periodic monitoring and re-evaluation to maintain acceptable risk levels, especially in case of extreme scenarios.Peer ReviewedPostprint (author's final draft
Assessment of green measures as coastal defences using numerical models
Climate change may reduce the performance and design life of “grey” coastal engineering interventions. Green solutions can be combined with present infrastructures providing extra flexibility to adapt our present beaches with affordable costs. This paper assesses the behaviour of a typology of green solutions (seagrass meadows) via numerical hydro-morphodynamic modelling for an erosive beach prone to episodic flooding, under typical Mediterranean conditions. A multivariate method for jointly assessing flooding and erosion via copulas is proposed and developed. In the considered pilot site, different layouts have been tested by analysing their efficiency and limits. It is concluded that, for moderate SLR rates (RCP 4.5. central trend), these green measures could attenuate efficiently the expected changes in marine drivers. However, the complexity of eco-hydraulic interactions on which the Nature Based Solutions depend would demand periodic monitoring and evaluation for maintaining acceptable risk levels, especially in the case of high-end scenarios.Postprint (published version
First considerations on environmental friendly solutions to protect the southern Romanian coast
The aim of this work is to assess the effect of a nature-based solution for reducing wave heights on the Southern Romanian coast. Apart from investigating the presence of seagrass from the environmental point of view, there is also a need to assess its impact on the coastal hydrodynamics. The impact on the wave heights of a seagrass meadow located on the Southern Romanian coast, has been analyzed by means of a wave model. In this purpose, several numerical simulations have been performed, both for low and average offshore wave conditions, available from a previous wave climate study, which used a 30 years climate data set. A first set of simulations have been performed in the absence of seagrass. Then a seagrass meadow has been added to our grid and the wave model has been run in the same offshore wave conditions. The differences in computed nearshore wave heights reach around 4% for moderate energy waves. These results show that, on the Southern Romanian coast, seagrass could be regarded as an additional measure for nearshore wave attenuation.Peer ReviewedPostprint (published version
Coastal flooding and erosion under a changing climate: implications at a low-lying coast (Ebro delta)
Episodic coastal hazards associated to sea storms are responsible for sudden and intense changes in coastal morphology. Climate change and local anthropogenic activities such as river regulation and urban growth are raising risk levels in coastal hotspots, like low-lying areas of river deltas. This urges to revise present management strategies to guarantee their future sustainability, demanding a detailed diagnostic of the hazard evolution. In this paper, flooding and erosion under current and future conditions have been assessed at local scale at the urban area of Riumar, a touristic enclave placed at the Ebro Delta (Spain). Process-based models have been used to address the interaction between beach morphology and storm waves, as well as the influence of coastal environment complexity. Storm waves have been propagated with SWAN wave model and have provided the forcings for XBeach, a 2DH hydro-morphodynamic model. Results show that future trends in sea level rise and wave forcing produce non-linear variations of the flooded area and the volume of mobilized sediment resulting from marine storms. In particular, the balance between flooding and sediment transport will shift depending on the relative sea level. Wave induced flooding and long-shore sand transport seem to be diminished in the future, whereas static sea level flooding and cross-shore sediment transport are exacerbated. Therefore, the characterization of tipping points in the coastal response can help to develop robust and adaptive plans to manage climate change impact in sandy wave dominated coasts with a low-lying hinterland and a complex shoreline morphology.Peer ReviewedPostprint (published version
Occurrence of Mycotoxins in Swine Feeding from Spain
A survey including 228 pig feed samples from Spain has been developed, exploring the
occurrence of 19 mycotoxins (aflatoxins B1, B2, G1 and G2, ochratoxin A, fumonisins B1 and B2,
citrinin, zearalenone, deoxynivalenol, fusarenon X, sterigmatocystin, T-2 toxin, HT-2 toxin, enniatins
A, A1, B and B2, and beauvericin). The samples were analysed by solid-liquid extraction followed by
liquid chromatography coupled with fluorescence or mass spectrometry detection. Enniatin B was
found in 100% of the samples (up to 1200 ug/kg) and beauvericin in more than 90%. Moreover, 40% of
samples were contaminated with more than five mycotoxins. This high occurrence is insurmountable
and surpasses all previous studies, probably due to the inclusion of emerging mycotoxins, scarcely
explored. The majority of the samples (96.9%) were in accordance with EU regulations, which do not
address emerging mycotoxins or co-occurrence. These results show that in order to ensure mycotoxin
absence, emerging mycotoxins should always be considered.This research was funded by SPANISH MINISTRY OF ECONOMY AND COMPETITIVENESS and
EUROPEAN REGIONAL DEVELOPMENT FUND (MINECO/FEDER, UE), grant number AGL2015-70708-R
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