177 research outputs found

    Analysis of trends and variability of water levels

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    Knowledge about the magnitude and frequency of extreme water levels is essential for assessing the risk of coastal flooding, which is the major coastal hazard worldwide. In the last years, significant effort has been directed to analyzing extreme water levels and their potential future changes under climate change. This thesis aims to contribute to this field by analyzing the historical variability of water levels and their components (i.e. tides and surges) at different temporal and spatial scales, and the potential effects of sea-level rise on the short-term variability of storm surges. Knowledge of both long and short term variability of water levels is required for reducing the uncertainties associated with the estimation of the likelihood of extreme water levels for flood impact assessments. Specifically, this thesis investigates long-term trends and inter-annual variability of water levels, tides and surges at two of the longest tide-gauge records of the southern hemisphere: Buenos Aires and Mar del Plata (Argentina). Over the last century, both water level series show an increasing trend caused by the rise of the mean sea-level, but also a decrease of the tidal amplitude. In the case of Buenos Aires, the changes in the tides are likely to be caused by the long-term changes in river discharge, as indicated by the high correlation observed between these two variables. In addition, river discharge is also highly correlated to the inter-annual variability of the extremes. Therefore, climate change induced changes in river discharge can in turn result in changes in the tides and storm surges at the Rio de la Plata estuary. Regarding the short-term variability of extreme water levels, two aspects are investigated in this thesis: namely the variability of the water level curve and the tide-surge interaction. The latter causes a dependency between the tide and the surge component, complicating their separation and posterior combination and thus the assessment of the water level curve evolution. To overcome this issue of tide-surge interaction, the skew surge parameter has been defined and shown to be independent on the high tidal level in semidiurnal regimes. Mixed semidiurnal regimes are characterized by a higher variability of high tidal levels, which can cause a dependency between the tide and the skew surge. This is statistically investigated for 15 sites worldwide, finding that half of these sites show a dependency between high tidal levels and extreme skew surges, and thus not any extreme skew surge can occur at any high tidal level. The skew surge does not contain information of the temporal evolution of the storm surge (water level curve), which is required as input of flood models. The uncertainties related to not accounting for the variability of the water curve when assessing coastal flooding is investigated for a coastal stretch of the German Bight. The high variability found at times around the water level peaks, when overflow/overtopping is more likely, can lead to a threefold increase of the total overflow volumes between events. Sea-level rise produces an increase of the water levels at times around the water level peaks, and this increase is relatively larger for low to moderate sea-level rise scenarios. Therefore, neglecting the variability of the water level curve can introduce large uncertainties in flood assessments and thus using the skew surge parameter might not be recommended when assessing coastal flooding. The results presented here provide important information about the long and short term variability of tides and storm surges that can be used for reducing uncertainties when estimating future extreme water levels and their associated coastal flood risk

    "Jules Verne volia ser marí"

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    ERBB2-target therapies in breast cancer: Investigating the biological mechanisms regulated by the pan-ERBB inhibitor Neratinib

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    Breast carcinoma (BCa) represents the leading cause of cancer-related death among women worldwide, and the overexpression of the Tyrosine Kinase Receptor (RTK) ERBB2 correlates with aggressive disease and poor prognosis. Thus, ERBB2 became one of the molecules chosen for the development of targeted therapies. The Pan-ERBB inhibitor Neratinib (NE), was approved by Food and Drug Administration (FDA) in 2017, for ERBB2+ BC treatment. Despite its broad clinical applications, its mechanisms of action toward the ERBB2 receptor and the downstream effects that sustain its clinical outcome are currently not fully understood. Here we explored the effects of IC50 low nanomolar doses of NE on ERBB2+ Breast Cancer cell lines regarding: the internalization of ERBB2 receptor, the regulation of intracellular trafficking, the autophagy process, and extracellular vesicle (EV) release. These are mechanisms highly dysregulated in cancer, sustaining cancer progression and resistance to treatments. Combining imaging, biochemical, and molecular approaches, in this study we assessed that low nanomolar IC50 doses of NE transiently reduced the activation of its downstream signaling pathways (Ras/MAPK and PI3K/Akt/mTOR), prompted an increase in the clathrin-mediated endocytosis and expanded the CD63+ MVB compartment without inducing a strong internalization of the ERBB2 receptor. Moreover, NE exerted its antitumoral function on the metastatic cell line SKBR-3 impairing autophagic machinery and processes. Additionally, we observed that cells under treatment increase the EV release while lowering the amount of ERBB2 on EVs, possibly preventing a potential metastatic mechanism. We reasoned that the outcome on autophagy could be the result of the reduced activation of TFEB and TFE3 transcription factors, two master regulators of autophagy and lysosomal exocytosis. Indeed, the expression of TFEB and TFE3 was strikingly increased in the cytosolic compartment upon treatment. Recent findings unveiled that TFEB and TFE3 are responsible for mitochondrial surveillance since they modulate a selective type of autophagy against damaged mitochondria (mitophagy). Therefore, we investigated mitochondrial morphology and functionality upon NE treatment. NE impaired the metabolic functionality of mitochondria that appeared also more fragmented compared to untreated cells, as a possible consequence of TFEB and TFE3 inhibition. Overall, these data extend the understanding of NE effects on ERBB2+ BCa cells, which result in an impairment of autophagy, a diminished ERBB2 potentially transferred to distant sites, and a detriment of mitochondrial metabolism, as its possible antitumoral functions

    Effect of fungal endophytes on plant growth and nutrient uptake in Trifolium subterraneum and Poa pratensis as affected by plant host specificity

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    [EN[ The introduction of well-adapted species, such as Trifolium subterraneum (subclover) and Poa pratensis (Kentucky bluegrass), might enhance the forage yield and quality of dehesa pastures for feeding livestock. However, the climatic hardness and poor soils in these agrosystems may limit plant establishment and development. Since fungal endophytes have been found to alleviate the environmental stresses of their host, the aim of this study was to assess the effect of five isolates on forage yield, nutritive value, and plant mineral uptake after their inoculation in the two abovementioned plant species. Two experiments were established (under greenhouse and field conditions) using plants inoculated with two isolates in 2012/2013 (Epicoccum nigrum, Sporormiella intermedia) and three isolates in 2013/2014 (Mucor hiemalis, Fusarium equiseti, Byssochlamys spectabilis). Fusarium equiseti (E346) increased the herbage yield of T. subterraneum under greenhouse conditions, and B. spectabilis improved the forage quality of T. subterraneum by reducing fiber content and of P. pratensis by increasing crude protein. S. intermedia increased the mineral uptake of Ca, Cu, Mn, Pb, Tl, and Zn in subclover, and M. hiemalis increased the uptake of K and Sr in Kentucky bluegrass. These results evidence the potential of the studied fungal endophytes to enhance herbage yield and nutritional value of forage, although further studies should include all of the target forage species as certain host specificity in the effect was observed.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research was funded by Project AGL2011-27454, granted by the Ministry of Economy and Competitiveness of Spain (the former Ministry of Science and Innovation) and by the European Regional Development Fund (ERDF).Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

    Potential of fungal endophytes isolated from pasture species in Spanish dehesas to produce enzymes under salt conditions

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    Producción CientíficaEndophytic fungi have been found to produce a wide range of extracellular enzymes, which are increasingly in demand for their industrial applications. Different by-products from the agrifood industry could be used as fungal growth substrates for the massive production of these enzymes, specifically as a way to revalorize them. However, such by-products often present unfavorable conditions for the microorganism’s growth, such as high salt concentrations. Therefore, the objective of the present study was to evaluate the potential of eleven endophytic fungi—which were isolated from plants growing in a harsh environment, specifically, from the Spanish dehesas—for the purposes of the in vitro production of six enzymes (i.e., amylase, lipase, protease, cellulase, pectinase and laccase) under both standard and salt-amended conditions. Under standard conditions, the studied endophytes produced between two and four of the six enzymes evaluated. In most of the producer fungal species, this enzymatic activity was relatively maintained when NaCl was added to the medium. Among the isolates evaluated, Sarocladium terricola (E025), Acremonium implicatum (E178), Microdiplodia hawaiiensis (E198), and an unidentified species (E586) were the most suitable candidates for the massive production of enzymes by using growth substrates with saline properties (such as those found in the many by-products from the agrifood industry). This study should be considered an initial approach by which to further study the identification of these compounds as well as to develop the optimization of their production by directly using those residues.Junta de Extremadura y Fondo Social Europeo - (grant PD18037

    Valoración de la presencia de arterias lumbares en los pacientes portadores de aneurisma de aorta abdominal

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    Los aneurismas de aorta abdominal son una patología de gran importancia, debido a su relativa frecuencia, y su potencial morbilidad y mortalidad. Dentro de las dos modalidades de tratamiento, la terapéutica endovascular se prefiere para pacientes de alto riesgo quirúrgico. Sus riesgos principales son el desarrollo de endoleaks o fugas, que producirían una presurización del saco aneurismático, su crecimiento y una posible ruptura, haciendo ineficaz la técnica. La forma de entrada de la sangre al saco se puede producir de diferentes formas, una de ellas es a través de las arterias permeables en sentido inverso (leak tipo II). Por ello, es importante estudiar la presencia de arterias lumbares permeables en estos pacientes a la hora de valorar su tratamiento, seguimiento y predecir complicaciones.Grado en Medicin

    La faula de Guillem de Torroella: ¿Literatura o política?

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    El objetivo de este trabajo es revisar la posición de la crítica respecto a La Faula de Guillem de Torroella, compuesta hacia 1375. Algunos intérpretes sostienen que hay en la obra un uso político de la leyenda artúrica, que la clave de lectura del relato es la esperanza de recuperar la independencia del reino de Mallorca. Otros autores afirman, por el contrario, que el significado del texto se comprende al situarlo dentro de la tradición literaria de la époc

    Long-term trends and variability of water levels and tides in Buenos Aires and Mar del Plata, Argentina

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    We present an analysis of the long-term trends and variability of extreme water and tidal levels and the main tidal constituents using long-term records from two tide gauges in the wider region of the Rio de la Plata estuary: Buenos Aires (1905-2013) and Mar del Plata (1956-2013). We find significant long-term trends in both tidal levels and the main tidal constituents (M2, S2, K1, O1, and the overtide M4) from a running harmonic analysis in both locations. The tidal range decreased on average 0.63 mm y-1, as a result of an increase of the low water levels and a decrease of the high water levels. We also find a secular decrease in the amplitude of the semi-diurnal constituents and an increase of the diurnal ones, but of different magnitudes at each location, which suggests that different processes are producing these changes. In Buenos Aires, an increase of river discharge into the estuary seems to reduce the tidal range by hampering the propagation of the tidal wave into the estuary, whereas no influence of river discharge on water and tidal levels can be detected in Mar del Plata. We believe that other factors such as thermohaline changes or the rise of mean sea-level may be responsible for the observed tidal range decrease. Despite the tidal long-term trends, we find no significant trends in the meteorological component of the tide-gauge records other than an increase in the mean sea-level. In addition, we explore teleconnections between the variability of the meteorological component of the tide-gauge records and climate drivers.Facultad de Ciencias Naturales y Muse
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