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Universitat Politècnica de Catalunya Departament d'Enginyeria Civil i Ambiental

Overview
Works: 1,073 works in 1,091 publications in 3 languages and 1,091 library holdings
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Most widely held works by Universitat Politècnica de Catalunya
Retinoic acid signaling pathway : gene regulation during the onset of puberty in the European sea bass by Paula Javiera Medina Henríquez( Book )

3 editions published in 2019 in English and held by 3 WorldCat member libraries worldwide

European sea bass (Dicentrarchus labrax) aquaculture is a thriving industry in Spain where it reached about 23,500 t and a market value of approximately 133 million euros. However, most of the sea bass farms produce a high percentage of males (70-90%) since the rearing temperature is increased during the initial stages of development to speed up development and growth. This is a problem because in this species, generally, females exhibit higher growth rates than males. This situation is aggravated as nearly 30% of these males reach puberty precociously during the first year of life, before attaining commercial size. Puberty is accompanied by a decrease in growth rates as energy diverts towards gonadal growth instead of somatic growth. In addition, it comes along with muscle waste and losses in the organoleptic properties of the meat. Because of these biological responses to captive breeding, there is a great need to understand the reproductive process and its control under intensive production conditions. The main objective of this thesis is to increase the knowledge of European sea bass reproduction. It is focussed on the role of the retinoic acid (RA) signalling pathway during early development and puberty. Using a costume-made sea bass oligomicroarray we found several groups of genes that were differentially expressed in testis during the onset of male puberty. One of these groups included genes that belong to the RA signalling pathway. RA is the active form of vitamin A and is known to be essential for the onset of meiosis in tetrapods, although its role in fish is yet to be confirmed. These results prompted us to deepen on the possible role of the RA signalling pathway in gonad development and gametogenesis. An in silico analysis allowed us to describe for the first time the structure, phylogeny and evolutionary history of several genes and proteins involved in the synthesis and degradation of RA in the European sea bass. After an exhaustive histological study of gonad development, we could accurately identify specific stages of ovarian and testicular differentiation in this species. The expression of the main genes of the RA signalling pathway in specific stages of gonad development confirmed its role in the onset of puberty. Finally, an in vitro culture system of testicular explants from juvenile prepubertal fish and of testicular preparations from adult fish were set up to study the role of this pathway in the onset of puberty in sea bass males. The functional responses of genes related to RA transport, synthesis, degradation and receptor signaling were evaluated in the presence of stimulators and an inhibitors of the pathway and in different meiosis scenarios. The results show that in the sea bass: a) the onset of meiosis coincides with an increase of 11KT levels and involves several pathways, including RA signalling; b) the enzymes related to RA synthesis and degradation have all the structural features to fulfil their specific functions; c) there is a well conserved evolutionary history of the enzymes involved in RA synthesis and degradation; d) the absence of stra8, a meiosis gatekeeper present in vertebrates and also in some fish, suggests that RA signaling in this species does not occur through the transduction of this particular gene; e) the genes involved in the RA signaling pathway are evolutionarily well conserved and play an important role in gonad development and gametogenesis; f) the expression dynamics of cyp26a1 during gonad development makes it an excellent molecular marker for the onset of meiosis. This thesis increases the understanding of the early molecular and endocrine events leading to puberty in the European sea bass by characterizing the RA signaling pathway. Moreover, it provides new questions and opens a novel research line to study the role of RA in puberty
Approach to acoustic mapping through continuous mobile monitoring by Guillermo Quintero Perez( Book )

2 editions published in 2019 in English and held by 2 WorldCat member libraries worldwide

For the production of representative noise maps, a large amount of information is necessary, which includes, among others, on-site measurements of environmental noise. Thus, for noise maps based on measurements, mobile sampling emerges as a possible solution for the enhancement of data acquisition. The present research proposes a complete framework to perform mobile sampling. Since the normative requires long-term values to be presented in a noise map, a sampling strategy based on temporal stratification, which reduces the required sampled days to estimate the annual equivalent noise level, is presented. Furthermore, to compute long-term values for the night period, since they are usually affected by noise sources different to traffic, specifically leisure noise, a complementary temporal and spatial stratification is also presented. Then, the statistical requirements to perform mobile noise measurements using bicycles is evaluated. The vehicles and bicycles journeys are reproduced based on micro-traffic simulation and then coupled with an acoustic modeling. The estimation error of LAeq for the mobile sampling is compared to reference static samples, in terms of the Root Mean Square Error (RMSE), and is computed for different aggregation radius of mobile receivers, and as a function of the number of passes-by and to the distance to its nearest cross street. To perform the mobile sampling on a real scenario, a low-cost noise monitoring device with the aim of performing georeferenced noise sampling, is developed. The accuracy tests suggest that it is able to acquire noise levels with an equivalent accuracy as a Class 2 sound level meter. Finally, to validate the results obtained through the modeling framework, a noise monitoring device is mounted on a bicycle and on-site mobile measurements are performed simultaneously to reference static ones. The same scenario is again recreated based on micro-simulation of traffic complemented with acoustic modeling. Then, for the simulated framework and the on-site measurements, the RMSE of the estimation of LAeq for different aggregation radius of mobile samples is compared to the reference static ones. It is confirmed that mobile sampling is a solution to improve noise data acquisition, which reduces the resources required to produce a noise map without sacrificing the accuracy and representativeness
Host-parasite interactions : the Parvilucifera sinerae model in marine microalgae by Elisabet Alacid Fernández( )

2 editions published in 2017 in English and held by 2 WorldCat member libraries worldwide

Parasitism is a widespread interaction that has evolved practically in all branches of the tree of life. It has historically been neglected in studies of marine microbial systems, limiting our understanding of marine food webs and biogeochemical cycles. Molecular tools have recently revealed many new host-parasite associations, placing parasites as key components of coastal marine planktonic and benthic communities. Phytoplankton sustains most of the marine primary production, sometimes causing massive proliferations or blooms, which may have negative consequences for humans and the ecosystem. Dinoflagellate blooms often occur in coastal areas, sometimes in co-occurrence with zoosporic parasite species. Occasionally, parasitic infections may be the main cause of dinoflagellate mortality, which can modulate bloom termination and consequently, their use has been suggested to biologically control natural blooms. Up to date, three groups of eukaryotic parasites of dinoflagellates have been described: Amoebophrya (Syndiniales), Parvilucifera (Perkinsozoa) and Dinomyces (Chytridiomycota). Such parasites can control the abundance of their hosts populations, and hence they can also affect phytoplankton dynamics, community structure and diversity. However, very little is still known about the ecology and diversity of these parasites, especially Parvilucifera and Dinomyces. Parvilucifera genus is one of the recently described groups of Perkinsozoa. To date, the genus comprises only 5 species, some of them described very recently. Most of the knowledge about this genus is related to the 18S rDNA sequences that allow its phylogenetic classification, and also with the morphological characters valuable for taxonomy studies. For this reason, this PhD thesis aims to better understand the microbial host-parasite interactions of marine planktonic communities by studying P. sinerae-dinoflagellates as a model system. Here we studied these host-parasite interactions at different scales, from cell-cell, to population and at community level, combining laboratory experiments and field studies. The use of several microscope techniques and molecular tools (TSA-FISH) have allowed the characterization of the life-cycle of P. sinerae and the kinetics of the infection stages. P. sinerae has a direct life cycle that causes the host death, with a short generation time and a high asexual reproduction rate, producing a huge offspring from a single infection (Chapter 1). Moreover, we unequivocally identified dymethilsulfide as the chemical cue that triggers zoospore activation and release from the dormant sporangium (Chapter 2). Our capacity to culture both partners of the association in the lab, P. sinerae and dinoflagellates, allowed for a series of cross-infection experiments, which resulted in the designation of P. sinerae as a generalist parasitoid, being able to infect up to 15 genera of dinoflagellates (Chapter 3). Furthermore, we determined that P. sinerae exhibits preferences for certain host species, which enhance parasitoid reproduction rate and transmission (Chapter 4). The study of in situ Parvilucifera detection and estimates of the flux of infected host cells using sediment traps has allowed us to unveil the occurrence, dynamics, and impact of Parvilucifera infection during Alexandrium minutum natural blooms (Chapter 5). We showed that outbreaks of the dinoflagellate A. minutum were always accompanied by Parvilucifera infections, presenting a host-parasitoid temporal dynamic similar to predator-prey interactions, and contributing to bloom decrease with a similar magnitude than other biological loss factors. The analysis of this relationship at different scales has provided the necessary information to conclude that the ecology of Parvilucifera is well adapted to that of its blooming hosts, whose seasonal proliferations enhance Parvilucifera transmission, sustaining the parasitic populations in marine coastal environments
Ecosystem modelling in the Eastern Mediterranean Sea : the cumulative impact of alien species, fishing and climate change on the Israeli marine ecosystem by Xavier Corrales Ribas( Book )

2 editions published in 2019 in English and held by 2 WorldCat member libraries worldwide

Firstly, I reviewed modelling approaches that were used to assess the impact of invasive alien species (IAS) in aquatic ecosystems. According to the review, multispecies/ecosystem mechanistic models dominated the applications, with dynamic and non-spatial models being the most prevalent. Most of the models included an additional human stressor, mainly fisheries, climate change and/or nutrient loading. I summarised the main features of these applications and analysed their capabilities and limitations. Based on my conclusions, I reflected on future directions of development and applications of suitable modelling tools. The review showed that the Ecopath with Ecosim (EwE) modelling approach was frequently used to assess the impacts of already established IAS and highlighted its capabilities to forecast existing, emerging and potential new IAS. As a second step, I developed two static Ecopath ecosystem models using the EwE approach and representing the food web of the Israeli Mediterranean coast in 1990s and 2010s. I characterized the structure and functioning of the ecosystem and assessed past and current impacts of IAS and fishing. I then used the time-dynamic Ecosim module of EwE to fit the 1990s model to available time series of observations between both periods and to explore the historical dynamics of the ecosystem considering the effects of IAS, fishing dynamics and sea warming. Finally, the time-dynamic ecosystem model was used to analyse alternative future simulations of ecosystem change. Particularly, and after interacting with key stakeholders, I assessed the future effects of a new set of fishing regulations currently being implemented in Israel, future changes in sea temperature following IPCC (Intergovernmental Panel on Climate Change) scenario projections and the potential increases in IAS biomass. I investigated the impacts of the stressors separately, and then I combined them to evaluate their cumulative effects. Results from the static Ecopath models highlighted that the Israeli marine ecosystem, despite productivity differences, shared some structural and functional traits with other Mediterranean ecosystems such as the dominance of the pelagic domain in term of flows, the important role of detritus through low trophic levels and the importance of the benthic-pelagic coupling. In both time periods investigated, the same keystone groups were identified with the exception of European hake in 2010s, which showed a decline in its keystone role. This may indicate that hake lost its ecological role due to population declines. Most of the functional groups identified as keystone species were previously identified as keystones in other Mediterranean ecosystems, such as dolphins, large pelagic fishes, sharks and squids. The temporal dynamic Ecosim model indicated that trophic interactions, ocean warming and fishing were important drivers of the ecosystem dynamics. In general, temporal biomass trends revealed that native demersal predators and native medium trophic level fishes largely declined over time, while an increase over time of alien species was observed. Results from ecological indicators suggested a degradation pattern of the ecosystem over time. Future scenarios using the temporal dynamic Ecosim model showed overall potential benefits of fishing effort reductions in the future, and detrimental impacts of increasing sea temperature and increasing biomass of alien species. Cumulative scenarios highlighted that the beneficial effects of fisheries reduction could be dampened by the impact of increasing sea temperature and alien species when acting together. These results support the need for reducing local and regional stressors, such as fishing and biological invasions, to retain marine ecosystems within a "safe operating space" and ensure ecosystem resilience in an ongoing warming and impacted sea
Floating plastic debris in the central and western Mediterranean sea : current status and its social perception by Luis F Ruiz-Orejón( Book )

2 editions published in 2018 in English and held by 2 WorldCat member libraries worldwide

Plastics are currently one of the most widely distributed litter in marine ecosystems worldwide. The floating fraction of these debris are estimated to represent about 1% of the plastics that enter into the marine environment where subtropical ocean gyres are considered to be the main convergence zones of floating plastics. The dense social system around the Mediterranean Sea pressures this environment being aggravated due to its semi-enclosed condition. Concern about plastic waste has been increasing in recent years due to the adverse effects it can cause on the Mediterranean ecological systems, its persistence in the environment and the consequences for social systems. The problem of plastic pollution has a profound social origin. In this context, this work is aimed to assess the current state of the problem of floating plastic debris in the Central and Western Mediterranean in both environmental and social systems. From the ecological point of view, the surface of the Mediterranean was sampled on three different spatial scales; a regional macro scale in the Northwestern-Central Med. Sea, a regional micro scale in the Balearic Islands (Spain) and a local scale focused on the current MPA of the Menorca Channel (Balearic Islands). In addition, a pilot seasonal study was carried out in the local scale. The distribution and concentrations observed along the sea surface confirmed the omnipresence and persistence of plastic waste in marine ecosystems, resulting in maximum concentrations of particles off the NW coast of Ibiza Island (Spain) and concentration by weight near to the Gulf of Taranto (Italy). The results of the 139 samples analyzed in total confirm the significant superiority of microplastics on the colbded waste observed in the Mediterranean surface. In general, the concentration of plastic waste was higher in the areas near the coast, with concentrations significantly higher in the Balearic Islands than in the rest of the Mediterranean. However, the seasonal distribution of plastic concentrations seems to be influenced by multiple factors in which particles appear to be directed by oceanographic variables, while the weight by social variables. From a social point of view, the perception and awareness of three key stakeholders in the decision-making processes (experts, public administrators and business agents) and beach users on the island of Mallorca were assessed. Perceptions of the plastic issue were explored by applying a mixed methodology in three focus groups formed by Mallorcan stakeholders. The participants' broad view of plastic problems was demonstrated, in which topics covering most of the material's life cycle were developed. The main problems detected were centered within the social systems, where the excess of plastic used in the production and consumption processes was considered the main problem of plastic by the three groups. However, its approach to the definition of the problem was limited to the areas in which stakeholders were defined. Through a questionnaire distributed on the beaches, the perception and awareness of its users was analyzed. The result showed that users perceived plastics as an important environmental problem whose main causes are plastic excess and lack of public awareness, as well as, present a rejection attitude to the waste found on the beaches that influences the user's selection. The results presented in this doctoral thesis contribute to the development and application of knowledge of the state of plastic pollution in the Mediterranean Sea in the context of social-ecological systems
Microalgae in aquaculture wastewater : a new forecasting method of production in a marine system by Valeria Andreotti( Book )

2 editions published in 2019 in English and held by 2 WorldCat member libraries worldwide

In the field of aquaculture, the main microalgae application is animal nutrition, in which they can be used as an unprocessed component, or as dried material for feed preparations. Moreover, microalgae can assimilate the main nutrients dissolved in aquaculture wastewater reducing the environmental impact of aquaculture and at the same time producing valuable biomass. Because of the variability of wastewater, it is not easy to predict the microalgae production, nevertheless, the mathematical model could offer the possibility to study microalgae growth in different conditions. Mathematical models are used to forecast algal productivity and nutrient removal efficiency in synthetic media and in urban wastewater, but they were never been implemented and calibrated for aquaculture wastewater. The main outcome of the present Ph.D. thesis was to calibrate and validate the integrated mechanistic model BIO_ALGAE with experimental data obtained from the cultivation of marine microalgae in aquaculture wastewater. This model includes crucial physical and biokinetic processes to simulate microalgae growth in wastewater, and in a different type of photobioreactors. BIO_ALGAE was used to understanding the slight diurnal variations, which could have not been detected with experimental samples. Preliminary respirometric tests were carried out on the microalgal-bacterial suspension. These respirometric outputs were compared with process rates affecting dissolved oxygen dynamics computed by the mathematical model. In the experimental part of this thesis project, the productivity and capacity in the bioremediation of three marine microalgae species, Tetraselmis suecica, Dunaliella tertiolecta and Isochrysis galbana was investigated and compared. Wastewater generated during the production of grey mullet (Mugil cephalus) and sea bream (Sparus aurata) was used as culture medium. The experiments were conducted in batch and in semi-continuous conditions using column photobioreactors with differents volumes. It is known that under different stress conditions, the microalgae produce bioactive compounds, therefore, aquaculture wastewater was used as substitute synthetic cultivation medium to test the production of lipids, proteins, and carbohydrates in the microalgal biomass. Moreover, these species were cultivated in unsterilized culture media, and this reduces energy consumption, costs, and efforts. This study confirms the potential to employ Tetraselmis suecica in an Integrated Multi-Trophic Aquaculture system for biomass production and bioremediation of wastewater and identifies Dunaliella tertiolecta as another valid candidate species. T. suecica was therefore selected for the validation of BIO_ALGAE model. For the first time, BIO_ALGAE model was applied in aquaculture system and highlights a good agreement between experimental data and simulations. This model has proved to be an efficient tool to understand microalgae production in aquaculture wastewater treatment and to simulate the dynamics of different conditions in closed photobioreactors. Indeed, BIO_ALGAE describes the factors that influence microalgae growth and this is a useful approach to predict microalgal biomass with the optimization of the operating conditions
Simulation tools for biomechanical applications with PGD-based reduced order models by Xi Zou( )

2 editions published between 2018 and 2019 in English and held by 2 WorldCat member libraries worldwide

Numerical simulation tools are generally used in all modern engineering fields, especially those having difficulties in performing large number of practical experiments, such as biomechanics. Among the computational methods, Finite Element (FE) is an essential tool. Nowadays, the fast-growing computational techniques, from the upgrading hardware to the emerging of novel algorithm, have already enabled extensive applications in biomechanics. For applications that require fast response and/or multiple queries, Reduced Order Modelling (ROM) methods have been developed based on existing methods such as FE, and have eventually enabled real-time numerical simulation for a large variety of engineering problems. In this thesis, several novel computational techniques are developed to explore the capability of Proper Generalised Decomposition (PGD), which is an important approach of ROM. To assess the usability of the PGD-based ROM for biomechanical applications, a real human femur bone is chosen to study its mechanical behaviour as an example. Standard image-based modelling procedure in biomechanics is performed to create an FE model which is then validated with in vitro experimental results. As a basis of this work, the medical image processing has to be performed, in order to generate an available FE model. This model is validated according to data collected from a previously performed \textit{in vitro} experimental test. The full procedure of image-based model generation and the validation of generated model is described in Chapter 2. As a major objective of this thesis, a non-intrusive scheme for the PGD framework is developed in Chapter 3. It is implemented using in-house developed Matlab (Mathworks, USA) code to conduct the PGD work flow, and calling Abaqus as an external solver for devised fictitious mechanical problems. The transformation of data from computed tomography (CT) image set to FE model including inhomogeneous material properties is subjected to some physical constraints, and when applying the load, there are also geometric constraints limiting the locations where load could be applied. These constraints will lead to a constrained parameter space, which possibly has difficulty to be separated in a Cartesian fashion. Therefore, a novel strategy to separate the parameters in a collective manner is proposed in Chapter 4. Chapter 5 details a comprehensive application in biomechanics, the methodologies proposed in Chapter 3 and 4 are applied on the practical model generated in Chapter 2. As a typical application of the PGD vademecum, a material property identification problem is discussed. Further PGD vademecum is generated using the identified material properties with variable loading locations, and with this vademecum, real-time mechanical response of the femur is available. In addition, for the purpose of extending the methodologies to orthotropic materials, which is commonly used in biomechanics, in Chapter 6 another linear elastic model is investigated with the non-intrusive PGD scheme. Nowadays, isogeometric analysis (IGA) is a very popular tool in computational mechanics. It is appealing to take advantage of non-uniform rational B-splines (NURBS) to discretise the model. For PGD, using B-splines for the discretisation of the parameter space could improve the quality of vademecum, especially for problems involving sensitivities with respect to the parameters during the online computations. It is important and necessary to extend the PGD framework to nonlinear solid mechanics, because most biological soft tissues have been observed nonlinear mechanical behaviours. Consequently, in Chapter 7 we have developed a PGD framework for the St.Venant-Kirchhoff constitutive model using the Picard linearisation which is consistent with the fixed-point iteration algorithm commonly used in PGD. In Chapter 8, conclusive remarks are addressed as well as forecasts of possible future works
The coastal risk landscape application on the Catalan coast by Caridad Ballesteros Martínez( Book )

2 editions published in 2017 in English and held by 2 WorldCat member libraries worldwide

Coastal zones concentrate an elevated number of values both natural and socio-economic, making them very vulnerable to the potential effects of natural hazards. Therefore, effective risk management requires a holistic analysis in which the multiple components that determine risk are taken into account. This has been addressed with use of The Coastal Risk Landscape concept, which can be defined as the integrated risk of coastal areas resulting from the action and interaction of natural and/or human induced hazards on existing values and assets. A methodology to assess coastal erosion and flood risk at a regional scale is presented using an integrated analysis of the main processes associated to forcings that induce erosion and flooding at different temporal scales (episodic, medium and long-term) as well as an analysis of the socio-economic consequences. This has been framed within the Source-Pathway-Receptor-Consequences (SPRC) model, in which the "pathway" has been adapted to represent each hazard by considering the different related processes acting at different timescales. To this end, each component (process) is first evaluated individually and classified into an intensity scale which allows an integration and comparison of their relative importance along the coast. An intensity scale associated with erosion components (episodic, medium and long-term) has been defined considering how the beach is affected, in terms of providing recreation and protection functions. Then, selected variables are used to assess the flooding components (flash floods, marine floods and inundation by sea level rise), related to the characteristics of their processes, and classified into an intensity scale.This permits an assessment of their individual contribution in order to analyse their relative contribution to the total risk. The consequences of erosion and flooding have been determined separately taking into account the most relevant impacts. In the case of erosion, socio-economic values of the two coastal functions analysed have been considered. Then, the erosion components are combined in a risk matrix, providing risk values for different coastal management targets (i.e. recreation and protection). In the case of flooding, the consequences are assessed by characterising the values at exposure based on an indicator that encompasses five categories (land use, population and social vulnerability, transport system, business settings and utilities). The total risk is expressed as the combination of the hazard and the exposure. All of this is integrated at a management scale, represented by the municipality. This methodology has been applied to 219 km of beaches along the Catalan coast (NE Spanish Mediterranean). Results obtained indicate that despite the generally good condition of the coast to provide recreation and protection functions at present, a future projection at 2035, which considers the medium and long-term erosion components (background erosion+ SLR-induced erosion), shows an increase in the risk to provide such functions. Thus, most of the municipalities with a tourism focus will be unable to support a recreational use, and the Maresme comarca will barely provide the required level of protection by 2035 year. Moreover, episodic flood components (marine and flash flooding) can be considered the most relevant along the coast, with generally medium risk values. The long-term flood component (SLR) only affects low-lying areas, with the Ebro delta being the most important. Results indicate that the Maresme comarca is the most sensitive region to storm-induced components in the Catalan coast
Sistema de categorización integral de mezclas asfálticas para capas finas y ultrafinas en pavimentos by Livia Garcia Gil( Book )

2 editions published in 2019 in Spanish and held by 2 WorldCat member libraries worldwide

Traditional design procedures of asphalt mixtures are based on volumetric parameters and the compliance with certain mechanical and functional properties, and do not provide minimum requirements in terms of cracking resistance, a property that plays a major role in the durability of the pavement, and neither promote the use of sustainable technologies. In order to overcome these barriers and seek the balance between properties, this doctoral thesis aims to develop a multi-labelling scheme for asphalt mixtures for thin asphalt wearing courses according to their mechanical, functional and environmental performance. The developed labelling system allows the comparison and benchmarking of different asphalt mixtures, providing the chance to choose the most safety and environmentally demanding option for each specific situation. The development of this tool involved the generation of an extensive database on mechanical functional and environmental performance of bituminous mixture; the lack of information about some properties made it necessary to carry out a laboratory testing and a monitoring phase to complete the database. Once all the data was collected, the labelling strategy for evaluating the performance of thin asphalt wearing courses was designed. The approached methodology is flexible enough to be tailored to suit countries' specific requirements because construction techniques, used materials, traffic, weather conditions, age of the pavement, preservation techniques, etc., differ from one country to another. In order to realize the potential of the developed tool, the study was focused on the Spanish case because different Spanish IMs were involved and all the collected data belongs to the Spanish road network. The findings in this research clearly demonstrate that the developed labelling scheme shows promise; it allows not only the assignation of performance labels to any asphalt mixture based on its attributes but also the comparison of features between different asphalt mixtures for thin asphalt wearing courses
Remobilització dels contaminants orgànics persistents en els ecosistemes polars costaners by Paulo Casal Rodríguez( Book )

2 editions published in 2018 in Catalan and held by 2 WorldCat member libraries worldwide

Persistent organic pollutants (POPs) constitute an heterogeneous group of chemical substances of great environmental relevance. Its persistence, bioaccumulation, long-range transport potential and negative effects on health and the environment have led to its study and international regulation. As a consequence, there has been a decrease in the primary sources of some of these substances, especially the "legacy" POPs. However, the consequent decrease in its concentrations in the atmospheric compartment favors the re-emission of POPs from soils, ice, snow and water. The Arctic and the Antarctic are remote regions, however they are contaminated by POPs. In the polar regions, persistence is increased due to low temperatures. Atmospheric deposition is also enhanced at low temperatures thanks to the scavenging of chemical compounds present in the atmosphere by the snow deposition and the low air-water and air-soil partition coefficients (a process known as "cold trapping"). In addition, biogeochemical controls such as change in vegetation cover, degradation or biological pump, influence the capture of POPs. All these processes promote the accumulation of POPs in soils, seawater and ice / snow in the polar regions, converting these matrices into reservoirs of "legacy" and emerging POPs in the polar ecosystem. However, the decrease in atmospheric concentrations, together with the increase in temperatures induced by climate change, can reverse the role of these compartments that previously acted as sinks. Furthermore, the glaciers retreat acts as a POPs source from an environmental compartment that is reducing its size on a global scale. This process, known as remobilization, has received increasing attention in the scientific community, as it has an impact on the environmental fate of POPs. Although previous observations confirm the occurrence of this process under certain circumstances, cascading changes in the different environmental compartments and their effects on other processes, on local biota and on human health, remain poorly understood. In this thesis, the processes of remobilization from an Arctic and Antarctic coastal zones were studied, for compounds with a wide range of physical-chemical properties. In the Arctic sampling area (Tromsø, Norway), the soil / snow-air exchange of PCBs, PAHs and OCPs was evaluated over a sampling period of 14 months. In general, atmospheric concentrations and soil / snow diffusive exchange followed a seasonality closely related to air temperature, and volatilization was observed during the warmer months. On the coast of Livingston Island (Antarctica), the remobilization of PFASs, PAHs, OCPs and PCBs was evaluated from sampling carried out during a 3-month campaign, which included, for the first time, the simultaneous sampling of plankton, sea water, snow (including snowmelt and snow depositon), air and the determination of various fugacities, diffusive exchange fluxes and mass balances, among other analysis. Snow deposition and seasonal melting were established as key factors for all the compounds studied in POPs cycling in coastal polar ecosystems. The melting of ice and snow, linked to changes in temperature, influenced POPs concentrations in coastal waters, and as a result induced the remission of the most volatile POPs into the atmosphere. The resulting concentrations of plankton in the Antarctic coastal environment were determined for all target families, as it is a key element in the biological pump and the first step in the bioaccumulation and transfer in marine food webs
Analysis of the ocean dynamics in a wind-jet region using high-resolution models by Laura Ràfols Bundó( Book )

2 editions published in 2018 in English and held by 2 WorldCat member libraries worldwide

The water currents and the wave field at the Catalan coast (in the Northwestern Mediterranean Sea) are investigated. However, the main research is focused at the northern margin of the Ebro Shelf, where there is a relatively high amount of data for study purposes and where episodes of strong northwesterly wind occur. In such cases, the wind is channeled through the Ebro Valley and intensifies upon reaching the sea, resulting in a wind jet. The research has been divided into four parts: (1) the study of the water circulation induced by a wind jet, by means of the Regional Ocean Modeling System (ROMS) numerical model; (2) the study of the waves dynamics induced by a wind jet, using the Simulating WAves Nearshore (SWAN) numerical model; (3) the study of the wave-current interactions during wind-jet events, coupling the numerical models used formerly; and (4) the implementation and validation of a waves and currents forecasting system at the Catalan coast, based on the knowledge gained during the research performed in the previous parts
El arte de la ingeniería, la ingeniería de la arquitectura, la arquitectura del ingeniero : arte, concepto y lenguaje en el proyecto by Mario Fernández González( Book )

2 editions published in 2019 in Spanish and held by 2 WorldCat member libraries worldwide

This PhD thesis aims to analyse and verify the tense and intense relation that is established between the architecture, civil engineering and art worlds. Such analysis is conducted not only in a formal manner, but also at a level which is more conceptual and profound and whose basis are the three concepts that were posed by Severre Fehn at one of his last conferences, which was held under the title of "The Skin, the Cut, & the Bandage"1. This has been done in order to verify, in a general but also more particular way, that they shape their own operational language of the disciplinary endeavour, on whose limits common features of these three disciplines can be found, features that have seeped into research paces, guiding the sight, observation, contemplation and speculation, leading to the development of a theoretical frame which allows the connection between architectural and engineering interventions inside the operative field of art in the landscape. In this regard, the development of such research leads to the exhaustive analysis of these three concepts, posed in a common space located on the limit of these three disciplines, expectant and mindful of the notion of time, memory and place. Elements that, at the same time, configure themselves by means of the tectonic, conceptual and symbolic and lay an Ariadna's Thread of the common language in whom invariants and patterns can be found, which underlie the same procedural operative that is bounded to the territory accommodating the work and which respond to a dialogical and at the same time, dialectical relation between the work and its landscape. Likewise, the work shapes an atmosphere that considers the crossing between the epistemological side of the discipline, the hermeneutic part of the thought that gazes at that which is conceptual, and the phenomenological part of the perception of the individual whom experiments the landscape
Bedforms and associated sediment dynamics on the inner shelves at different spatio-temporal scales by Queralt Guerrero Sánchez( Book )

2 editions published between 2018 and 2019 in English and held by 2 WorldCat member libraries worldwide

This Thesis conducts the study of bedform development and dynamics in the inner shelf integrating observations at different spatial and temporal scales. An initial assumption is that different scales of sedimentary processes strongly interact between them and small-scale sedimentary processes intended to foster those of larger scale. The potential contribution of small-scale bedforms to the sediment transport is particularly addressed. The study includes the monitoring and analysis of sand ridges, ripples and near-bottom suspended sediment variations at the Ebro Delta (NW Mediterranean Sea) and Perranporth (Atlantic Ocean) inner shelves. A sand ridge field with maximum ridges heights of 2.5 m and 400 m spaced is located over a retreating lobe in the Ebro Delta. Ridges are mostly symmetric arranging obliquely to the shoreline. The change of the main Ebro River channel led to the progressive abandonment of the former river mouth and to the severe coastal retreatment, providing large amount of sediment available in the coastal zone. NW winds induce strong near-bottom currents flowing towards the SE, which are able to transport sediment and produce ridge formation and migration towards the SE at ̃10 m/y. The characteristics of the Ebro sand ridges match well with those of shoreface-connected sand ridges and, particularly, with the initial stages of sand ridge development on storm-dominated continental shelves. Time-scales related to their genesis can be within a few decades. The presence of ripples on the different inner shelves is the most usual situation under low- to moderate-energetic conditions. In the wave-dominated and tideless coast (Ebro Delta) ripples were observed superimposed on sand ridges. Four types were identified: small undulations that were the precursor ripples, 2D wave-ripples, current-dominated 2D-3D-ripples, and combined wave-current 3D-ripples. The wave-ripples were static while the current-dominated ripples migrated. In a macro-tidal sandy beach exposed to high-energetic Atlantic storms (Perranporth), only wave-ripples were developed arranging orthogonal to wave approach and they were static. The size of ripples changed from larger (developed in equilibrium conditions) to smaller ripples, the latter interpreted as degraded ripples in wash-out conditions. The ripple prediction did not well-adjust to neither ripple appearance nor dimension. However, if the observed thresholds of seabed states are applied the model improves ripple appearance forecast. The near-bottom suspended sediment variability from seconds to months in the Ebro Delta is described distinguishing between waves, currents, and combined wave-currents conditions. In general, waves dominated the sediment resuspensions although strong currents also have an important contribution in the suspended sediment concentration (SSC) increases. The time-averaged SSC usually showed redundant structure by forming three layers with different patterns. In the lower and intermediate layers the SSC oscillated at gravity and infragravity wave frequencies. Time-varying and instantaneous profiles exhibit sediment patterns potentially related to ripples. The potential role of ripple migration as an additional long-term mechanism of sediment transport was analysed. In Perranporth, wave ripples are stationary and did not contribute to beach recovery because of wave orbital symmetry. The sediment transport is alongshore during low-energetic regimes and cross-shore during more energetic regimes when ripples are washed-out. In the Ebro Delta, 3D-ripples migration agrees with sand ridges migration direction towards the SE. The respective migration rates and their differences in size, support that a subordinate part of sand ridge migration can be the result of ripple migration contribution under low-, moderate-regimes, suggesting that in specific environments, dynamics of small-scale bedforms can play a subordinate but not negligible role in the evolution of larger bedforms
Variability of the planktonic cnidarian community at different spatio-temporal scales along the Catalan coast (Northwestern Mediterranean) by Elena Guerrero( )

2 editions published in 2017 in English and held by 2 WorldCat member libraries worldwide

Planktonic cnidarians are those species or their stages in the phylum Cnidaria that spent their life in the water column and therefore, are tightly linked to oceanographic dynamics and water mass structures, such as fronts and gyres. The objective of this thesis is to understand the variability of the planktonic cnidarian community inhabiting the Catalan coast (NW Mediterranean) at different spatio-temporal scales, and their relationships with the hydrography and environmental parameters that characterized the study area. At short time scales (10 days), in spring, important changes in the abundance and spatial distribution of the species were closely related to the shifting positions of a density front. The front acted as a barrier limiting offshore displacement of the two most dominant species. At an interannual scale, changes in the abundance, structure and latitudinal distribution of the summer community were observed when comparing extreme warm (July 2003) and standard conditions (July 2004). The exceptional warm conditions occurred in July 2003 due to a heat wave, lead to a reduction of the total abundance of the community and the latitudinal community distribution was reinforced. At an interdecadal scale, changes in species abundance, community composition and spatial distribution patterns were found during the month of June. Total Cnidaria abundance increased and the latitudinal community distribution patterns were reinforced when comparing three representative years (1983, 2004 and 2011) of the climatic and anthropogenic changes occurred during the last three decades in the NW Mediterranean. Temperature was the main environmental factor explaining these changes, representative of the climatic evolution from the colder 1980s to the warmer 2010s. Although, it is likely that others anthropogenic factors such us overfishing may have contributed to the observed changes over time. All these results are based in the study of a large and heterogeneous mesoscale area, characterized for different environmental gradients: bathymetry, temperature, salinity and primary production, as well as in the species level identification of the whole community. The planktonic cnidarian community along the Catalan coast presents a high variability both at temporal and spatial scales and is tightly related to hydrographic and environmental factors of the area, and to climatic and anthropogenic changes. These results show that it is extremely important to study and monitore planktonic cnidarians (considered as gelatinous zooplankton) in mesoscale spatial areas and at species level in order to assess possible changes at a temporal scales, since species and community spatial changes are sensitive indicators to climate change
Detección de errores en ortofotogramas mediante la visión estéreo by Héctor Sousa Vilchez( )

2 editions published in 2016 in Spanish and held by 2 WorldCat member libraries worldwide

En este proyecto se ha implementado un programa para ayudar en la detección de errores de ortofotogramas mediante la visión estéreo. Se ha usado el lenguaje C++ con el apoyo de las librerías Open Graphic Library (OpenGL) para el procesamiento de imágenes y Microsoft Foundation Classes (MFC) para la interfaz gráfica. El programa nos permite visualizar en estéreo un par de ortoimágenes que comparten una zona de solapamiento. Si el modelo y las imágenes son correctos, se espera una visualización plana y sin relieves. En el caso de que existan discrepancias, entonces el operador podrá acotar rápidamente las zonas con problemas y podrá corregirlas apropiadamente. El trabajo se divide en tres apartados. El primero donde se explican los conceptos teóricos necesarios, un segundo apartado donde se expone cómo configurar la computadora para la visualización 3D. Por último, la parte práctica que corresponde al diseño e implementación de los diferentes módulos, donde se muestra el funcionamiento del programa y la exposición de los resultados obtenidos
Subsurface as a bioreactor : interaction between physical heterogeneity and microbial processes by Núria Perujo Buxeda( )

2 editions published between 2018 and 2019 in English and held by 2 WorldCat member libraries worldwide

Infiltration systems are water treatment technologies where water vertically percolates through porous media while several biogeochemical processes occur. Biofilms are the main responsible for those biogeochemical processes due to their ability to colonize sediments as well as due to their role in transformation of organic matter and nutrients in aquatic ecosystems and subsurface environments. However, an excessive biofilm growth in sand filtration systems can significantly reduce their infiltration capacity (bio-clogging), thus constraining the processes that occur therein. Sediment grain size distribution influences the performance of these systems since it determines hydrological characteristics in subsurface sediments influencing biofilm growth as well as the process rates of biogeochemical processes in depth. Furthermore, sediment grain size can also influence the occurrence and depth-extension of bio-clogging. The main objective of this doctoral thesis is to study the influence of grain size distributions on biogeochemical processes and on bio-clogging in depth in sand infiltration systems used as potential tertiary treatments for the removal of organic matter and nutrients in water. To achieve this objective, two infiltration experiments have been carried out: (a) a laboratory-scale columns experiment using 5 sediment grain size distributions used as potential infiltration systems (Chapter I) and (b) an outdoor infiltration experiment in sediment tanks using two sediment grain size distributions (Chapter II and Chapter III). The results of this thesis show how sediment grain size distribution influences biofilm establishment and growth, biogeochemical rates as well as occurrence of bio-clogging in surface sediments and in depth. Accordingly, coarse sediments (coarse system) allow higher biomass in depth but they do not have the ability to remove dissolved phosphorous; however, due to high input loads they showed higher process rates. Grain size distribution of coarse sediment in the upper layer and fine sediment in the bottom layer (coarse-fine system) promotes the accumulation of biomass at the interface of the two sediment layers which results in a hot-spot of microbial activity. In addition, it promotes nutrient accumulation in sediments (dissolved phosphorous removal) possibly due to the fact that its flow velocities are smaller than those of a coarse system and therefore the contact time between the water and sediment increases by promoting the assimilation and adsorption of nutrients in the porous medium. Biomass establishment in fine sediments (fine system) results in greater bio-clogging due to lower initial porosity compared to systems with coarse sediment on the surface. This lower porosity results in less space available to colonize, and due to this, biofilm in the top layer of the monolayer fine system could reach the maturity state earlier than the bilayer coarse-fine system. That, together with the lower flows in the fine system, favours the detachment of biofilm in the top layer and its transport in depth. EPS accumulation in depth (due to live bacteria release or due to transport from upper sediment layers) is the main factor causing K variations in depth (potential to cause deep-clogging). Results also showed that mixed sediments of fine and coarse sands (mixture system) and the fine-coarse system achieve similar performance than fine system reaching similar biomasses between them and lower process rates than the other grain size distributions studied
The use of new multiparametric observatory platforms for the remote monitoring and exploration of deep-sea ecosystems at day-night and seasonal temporal scales by Carolina Doya Le Besnerais( Book )

2 editions published in 2017 in English and held by 2 WorldCat member libraries worldwide

Traditional sampling technologies such as trawling but also novel ones as ROV surveying are oriented toward a high spatial coverage without repeating data collection at fixed seabed windows. The temporal repetition is often neglected so any reported difference in sampling among sites or studies may potentially be confounded with time-induced variations as a product of rhythmic population displacements within the continental margin seabed and water column 3D scenarios. Behaviour is an important life trait conditioning our perception of deep-sea biodiversity, being its rhythmic expression upon different diel (i.e. 24-h based day-night and tidal cycles) poorly known. In this context, technological step forward must be taken in order to observe community changes in deep-sea areas as a product of population behavioural patterns. Here, I studied how activity rhythms of benthic species within deep-sea communities modulate their composition, species abundances, richness, biodiversity and other life-history trait information in representative deep-sea environments through the use of multiparametric video-fixed cabled and non-cabled stations plus moving platforms. At the same time, I provided new methodological sampling hints on data collection protocols and analyses specifically tuned to the different characteristic of each observatory platform. I shed new light on the regulation that environmental cycles exert on animals' rhythmic behavior, revealing that the main environmental rulers affecting deep-sea benthic communities are still day-night indirect or more direct tidal-oriented cycles which act on endobenthic, benthopelagic, and nektobenthic migrations
Degradación de filtros solares UV mediante infiltración suelo-acuífero con simulación en columna by Ignacio Marín García( )

1 edition published in 2016 in Spanish and held by 1 WorldCat member library worldwide

Este proyecto de investigación pretende analizar el comportamiento de los filtros solares, contaminantes orgánicos presentes en nuestras vidas en cosméticos, productos de aseo personal, industrias etc, bajo diferentes condiciones de contorno. Los contaminantes orgánicos llevan tiempo siendo invesfiltigados bajo la atenta mirada de científicos dedicados al tratamiento de aguas debido a que su presencia está en auge y su composición representa un peligro potencial para la salud humana y los ecosistemas que nos rodean. Su solubilidad y difícil degradación hacen que los contaminantes permanezcan en el medio mucho tiempo contaminándolo de forma severa. Actualmente, no existe metodología específica para tratarlos o eliminarlos completamente en plantas depuradoras y así evitar su inclusión al medio natural. En este trabajo de Máster se analiza el comportamiento del filtro solar UV orgánico Benzofenona 3 (BP3), uno de los filtros solares más utilizados en todo el mundo y el que más se observa como contaminante en el medio ambiente. Este compuesto se sabe que se transforma en diferentes productos en los procesos metabólicos de los organismos vivos y también mediante procesos abióticos, como la fotodegradación. Estos productos de transformación constituyen, así mismo, contaminantes medioambientales. Para llevar a cabo dicho análisis, el primer paso consiste en recrear o simular el medio natural mediante el dimensionamiento hidráulico de dos columnas de estudio rellenas con material no reactivo. Con ello, se pretende estudiar el compuesto bajo condiciones parecidas a la realidad, controlando los parámetros experimentales de las columnas. El proceso a simular es la infiltración del contaminante desde la superficie del suelo hasta un acuífero. Una vez dimensionadas las columnas y simulado el terreno natural configurando un tiempo de retención coherente y contrastado con estudios recientes, se procede a someter la BP3 a diferentes ensayos bajo diferentes condiciones ambientales y redox, tanto en disolución con agua Milli-Q como en un medio natural, agua de río. Tras la recogida de muestras de cada uno de los ensayos, se estudia la presencia de BP3 y sus posibles derivados mediante metodologías analíticas de última generación basadas en la cromatografía de líquidos de alta eficacia y la espectrometría de masas (HPLC-MS). Finalmente se estudian los registros gracias al tratamiento de datos y al uso de software específico para cada uno de los equipos utilizados. Los resultados obtenidos indican que la BP3 no interacciona con el material del relleno de la columna ni al paso por ésta en condiciones de medio natural ni tampoco en condiciones oxidantes, ya que sólo se llega a detectar la BP3 y ningún producto de transformación
Intercalation mechanism of polycarboxylate-based superplasticizers into montmorillonite clays by Pere Borralleras Mas( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

The presence of clays in the sands used for concrete production interferes with the development of the fluidity of concrete, producing an instantaneous slump loss just after batching and the premature loss of fluidity. This interference occurs with all types of additives and clays but is especially problematic when combining sands containing expansive clays such as montmorillonites with new-generation high water-reducer/superplasticizer admixtures based on polycarboxylate polymers (PCE).Water-reducers based on PCE polymers offer much better performance than traditional superplasticizers based on sulfonated naphthalene polymers (BNS) and sulfonated melamine polymers (MNS), making great advances in concrete technology, both from the technical and economical point of view as in reducing the environmental impact associated to concrete. However, these advantages are inhibited when sands contain clays of the expansive type in their composition.All the preventive or corrective measures to mitigate the harmful effect of clays contained in sands result in increases of production costs and in greater environmental impact. For this reason, during the last years it has been tried to develop polymeric structures that offer the same benefits than polymers PCE but with improved tolerance against clays of the expansive type, such as montmorillonite clays, but without getting to reach solutions with guarantees of success, due to the complexity of the interaction process between PCE polymers and montmorillonite clays.This doctoral thesis aims to deepen knowledge about the mechanism of interaction between PCE polymers and montmorillonite clays, assuming that the deep understanding of the interaction mechanism is the essential previous step to finally develop high-performance, clay-insensitive superplasticizers for concrete. For this, the research is structured in three parts, motivated by the discrepancies that the current model of interaction proposed shows with the experimental results of sorption and fluidity loss. In the first part, it is intended to develop a test method that allows to observe the real expansion profiles of the clays in such a way that the mentioned discrepancies can be clarified. Secondly, with the proposed test method, it is intended to identify how the structure of PCE polymers, as well as the dosage used, influences on the expansion of montmorillonite clays produced by the absorption of polymer. And, thirdly, to identify how the properties of clay affect the interaction process.The first phase of the research campaign has made it possible to propose an improved test method for the d-spacing determination that revealed the real intercalation behavior, by which the number of PCE side chains intercalated into the interlaminar space of montmorillonite clays is up to ten times higher than that deducted from the traditional analytical method. And from the new test method proposed it has been possible to clarify the role of the different structures of PCE polymers and the properties of montmorillonite clays in the intercalation mechanism, in agreement with the experimental results of fluidity loss and of sorption behavior.Based on the mentioned achievements, an extended model for the intercalation mechanism has been proposed, whereby montmorillonite clays inhibit the dispersing capacity of PCE polymers, being able to identify the parts and properties of both the clay and the PCE polymers that control this process.With this contribution, the knowledge of the intercalation mechanism is extended to understand how the interaction between PCE polymers and montmorillonite clays is developed, which is the main objective of this research
Economic analysis on the impacts of climate change in the maresme coast by Antoni Walton de Atela( )

1 edition published in 2016 in English and held by 1 WorldCat member library worldwide

The main aim of this thesis is to develop a methodology to quantify the impacts of climate change on a local level and to express this result in economic terms. In particular, this project looks at Catalunya, Spain, and calculates the total economic losses that climate change may represent under a certain scenario for four vulnerable coastal zones in the Maresme, a region north of Barcelona. Chapter 2 identifies the climate change effects which must be considered when calculating the total economic losses in coastal zones. Based on the current scientific knowledge, it attempts to present past trends and future scenarios in both the global and local level, in order to establish the magnitude of the reported global changes. However, it leaves aside the impacts which are considered not to damage the coastal line in a significant matter, and hence the studied impacts are air and ocean temperature, precipitation, sea water salinity and mean sea level. In the third chapter, a literature review is presented in order to pave the road for the development of a methodology to calculate the impacts of climate change. In this chapter, several studies, reports and thesis are presented to give an overview of projects which have already tackled a similar problem, or which simply may provide tools for the following chapter. Following the literature overview and based on its results, a methodology is proposed in chapter 4 to evaluate the economic losses that climate change may have on a local level. It is divided following two perspectives, socioeconomic and natural losses, and a combined one underlining the particularity of the case of beaches. For socioeconomic impacts, the construction or buildings value is added to the land value. Transportation infrastructure is also accounted for, giving a per length unit value. As for natural losses, the ecosystem services approach is taken, by considering a natural environment as a sum of functions which represent a benefit to human society in a direct or indirect way. In the chapter 5 the case study is presented where four coastal zones of the Maresme region in Catalunya are studied. Following the methodology presented in the previous chapter, firstly, the identification of land uses is carried out. Then, the areas and lengths for each land use are calculated. The third step is to valuate in economic terms each subarea. Afterward a loss or unharmed criterion is adopted, in a similar way to pass/fail criteria, and each land use is considered to be lost to the impacts of climate change or to remain unharmed. Finally, the total losses are calculated in all four case studies by adding up the value of all the harmed areas. The sixth chapter presents the results for the four case studies, as well as a general overview of the estimated economic losses that climate change may represent for the Maresme region. The results point to a 962 M€ total loss, which represents 30% of the Maresme public capital. In this chapter, the limitations of this thesis are also presented, and future research is suggested in the areas that fall out of the scope of this study
 
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DECA

Universitat Politècnica de Catalunya. DECA

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