82 research outputs found

    Correlation between sea surface topography and bathymetry in shallow shelf waters in the Western Mediterranean

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    In this paper, gravimetric and altimetric data are used to assess an estimation of the sea surface topography in the Western Mediterranean Sea. This is a complex area from different points of view, due to the presence of several islands, coastal lines, shallow waters and a peculiar hydrologic equilibrium due to its proximity to the Atlantic water exchange area. First, a gravimetric geoid was computed using the least-squares collocation (LSC) procedure with the classical remove-restore technique. We also present a local mean sea surface generated from repeat ERS-1 altimeter data fitted to TOPEX. We chose this satellite because it offers a better spatial resolution than the TOPEX data. The time span used in the computations is one year. This is a useful interval for averaging out the regular seasonal variations, which are very large in this area. We present the comparisons between the gravimetric geoidal heights and the adjusted sea surface. This is a way to obtain a rough estimation of the sea surface topography (SST) since we also include the errors in the two surfaces and other oceanic signals. The differences obtained are physically reasonable with a mean of 17 cm and standard deviation (s.d.) of 39 cm. A significant similarity is observed between the features reproduced by these differences and the bathymetry in the area, suggesting some sort of correlation between both magnitudes for the studied region. If we accept such correlation, the SST may be described as a function of depth. This procedure lets us filter out the short wavelength part of the geoid from the first SST estimation

    Geodetic Study of the 2006–2010 Ground Deformation in La Palma (Canary Islands): Observational Results

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    La Palma is one of the youngest of the Canary Islands, and historically the most active. The recent activity and unrest in the archipelago, the moderate seismicity observed in 2017 and 2018 and the possibility of catastrophic landslides related to the Cumbre Vieja volcano have made it strongly advisable to ensure a realistic knowledge of the background surface deformation on the island. This will then allow any anomalous deformation related to potential volcanic unrest on the island to be detected by monitoring the surface deformation. We describe here the observation results obtained during the 2006–2010 period using geodetic techniques such as Global Navigation Satellite System (GNSS), Advanced Differential Synthetic Aperture Radar Interferometry (A-DInSAR) and microgravimetry. These results show that, although there are no significant associated variations in gravity, there is a clear surface deformation that is spatially and temporally variable. Our results are discussed from the point of view of the unrest and its implications for the definition of an operational geodetic monitoring system for the islan

    Detection of displacements on Tenerife Island, Canaries, using radar interferometry

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    Tenerife is one of the most well monitored islands of the Canaries, but the surveillance generally is centred on Las Canadas Caldera, where the Teide volcano is located. In the last 180 000 yr, the eruptions on Tenerife Island have never occurred in the same volcanic structure, except for the Teide and Pico Viejo central volcanic system, so that a complete monitoring network would have to cover the whole island. As a result, Synthetic Aperture Radar Interferometry (InSAR) is being used on Tenerife, because this space technique can provide a displacement map of the surface of the earth with centimetre precision. This paper presents the results obtained on Tenerife Island using 18 SAR images acquired by the ERS-1 and ERS-2 satellites during the period 1992-2000. Two important results have been obtained: no deformation on Las Canadas Caldera, coinciding with results obtained using terrestrial techniques, and two subsidence episodes outside monitoring areas in the NW of the island, in the region of the last historic eruptions. These results show that InSAR is a useful technique for monitoring the entire island, thus allowing us to discover deformations in areas that are not routinely or easily monitored. This technique has been used in combination with Global Positioning System (GPS) observation of a global network on the island to define a new geodetic monitoring system. The possible causes of the deformations observed have been studied in an endeavour to discern if they might be of natural origin, in particular linked to a reactivation of prior volcanic activity. Examination of the geophysical observations on the island, human activities underway and the results of the modelling seem to indicate that at least part of the deformations may be caused by changes in the groundwater level and therefore are not linked to a volcanic reactivation. This result is important because it implies that, if geodetic volcano monitoring is to be performed on the island, the system used must be capable of discerning between various possible origins of the deformation by analysing their patterns and ancillary information from other sources. In this regard, InSAR is a basic tool on account of its unpaired wide area coverage and spatial density

    Registro de rayos gamma y caracterización de minerales arcillosos en la Formación San Felipe (cretácico superior) en la localidad Puerto Pastores (Galeana, N.L.)

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    Se ha realizado el registro de rayos gamma y la caracterización de minerales arcillosos en un perfil de la Formación San Felipe (Cretácico Superior, Sierra Madre Oriental) expuesto en la localidad Puerto Pastores (Galeana, N.L.). Se registraron lecturas utilizando un radiómetro GRS-500 Scintrex para radiación gamma total (Tc1, 181 cps en promedio), Potasio (K, 0.96%), Torio (Th, 5.05 ppm) y Uranio (U, 8.16 ppm). En general, lutita y toba alterada son los materiales que presentan las concentraciones más altas en K, U y Th, mientras que horizontes carbonatados muestran valores más bajos. La información del material sedimentario es comparable a la reportada en la literatura. El arreglo de minerales arcillosos se detectó utilizando un difractómetro de polvos Rigaku MiniFlex, en la que destaca la illita y la montmorillonita

    Targeting the TWEAK–Fn14 pathway prevents dysfunction in cardiac calcium handling after acute kidney injury

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    Heart and kidney have a closely interrelated pathophysiology. Acute kidney injury (AKI) is associated with significantly increased rates of cardiovascular events, a relationship defined as cardiorenal syndrome type 3 (CRS3). The underlying mechanisms that trigger heart disease remain, however, unknown, particularly concerning the clinical impact of AKI on cardiac outcomes and overall mortality. Tumour necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor-inducible 14 (Fn14) are independently involved in the pathogenesis of both heart and kidney failure, and recent studies have proposed TWEAK as a possible therapeutic target; however, its specific role in cardiac damage associated with CRS3 remains to be clarified. Firstly, we demonstrated in a retrospective longitudinal clinical study that soluble TWEAK plasma levels were a predictive biomarker of mortality in patients with AKI. Furthermore, the exogenous application of TWEAK to native ventricular cardiomyocytes induced relevant calcium (Ca2+) handling alterations. Next, we investigated the role of the TWEAK–Fn14 axis in cardiomyocyte function following renal ischaemia–reperfusion (I/R) injury in mice. We observed that TWEAK–Fn14 signalling was activated in the hearts of AKI mice. Mice also showed significantly altered intra-cardiomyocyte Ca2+ handling and arrhythmogenic Ca2+ events through an impairment in sarcoplasmic reticulum Ca2+-adenosine triphosphatase 2a pump (SERCA2a) and ryanodine receptor (RyR2) function. Administration of anti-TWEAK antibody after reperfusion significantly improved alterations in Ca2+ cycling and arrhythmogenic events and prevented SERCA2a and RyR2 modifications. In conclusion, this study establishes the relevance of the TWEAK–Fn14 pathway in cardiac dysfunction linked to CRS3, both as a predictor of mortality in patients with AKI and as a Ca2+ mishandling inducer in cardiomyocytes, and highlights the cardioprotective benefits of TWEAK targeting in CRS3This work was mainly supported by projects from the Instituto de Salud Carlos III (ISCIII) (PI20/00763, PI20/01482, CPII20/00022, FI18/00261, FI21/00212, CD19/00029, IFEQ21/00012, PI19/00588, PI22/00469) and co-funded by the European Union, Ministerio de Universidades (FPU20/03005), Ministerio de Ciencia e Innovaci on (RYR2019-026916-I), the Education and Research Council of Madrid (PEJ-2021- AI/SAL-21426), Biomedicine Network Comunidad de Madrid (P2022/BMD-7223 CIFRA_COR-CM), Spanish Network in Inflammasoma and Pyroptosis in Chronic Disease and Cancer (RED2022-134511-T), and the Spanish Society of Nephrology SEN/SENEFRO Foundatio

    Adaptación de asignaturas seleccionadas de la titulación de Logopedia a créditos ETCS. Implicaciones del alumnado

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    Producción CientíficaSe presenta una primera experiencia práctica en el marco del proceso de Convergencia Europea de la enseñanza. El proyecto nace con el objetivo de adaptar asignaturas seleccionadas del actual plan de estudios de la Titulación (Diplomatura) de Logopedia al reciente “Sistema de Transferencia de Créditos Europeos” (créditos ECTS o European Credit Transfer System). Con este fin se crea una red de carácter nacional en la que participan la Universidad de Valladolid, Salamanca y Castilla-La Mancha. En la presente comunicación se explican de forma exhaustiva diversos aspectos relacionados con la elaboración del proyecto: selección de asignaturas, implicación de profesorado y alumnado, así como la programación de actividades y acciones que se están llevando a cabo actualmente

    GNSS 3D displacement field determination in Lorca (Murcia, Spain) subsidence area

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    Trabajo presentado en el AGU (American Geophysical Union) Fall Meeting: Advancing Earth and Space Science, celebrado en San Francisco (Estados Unidos), del 12 al 16 de diciembre de 2016Land subsidence associated to the overexploitation of aquifers represents a common hazard impacting extensive areas worldwide. Recently, González and Fernández (20101) revealed that the Alto Guadalentín Basin, located in southern Spain, is affected by the highest subsidence rates measured in Europe (about 10 cm/yr) as a direct consequence of long-term aquifer exploitation. They used ERS and ENVISAT radar data spanning the 1992¿2007 period. They identify a delayed transient nonlinear compaction of the Alto Guadalentín aquifer due to the 1990¿1995 drought period. Bonì et al. (2015) extend the previous studies using advanced DInSAR techniques to process ALOS PALSAR (2007¿2010) and COSMO-SkyMed (2011¿2012) radar images. The combination of multi-sensor SAR images with different resolutions allows for a wider monitoring time span of 20 years (1992¿2012) over the Alto Guadalentín Basin. All regional studies of the area to date are based on satellite radar interferometry using just ascending or descending acquisitions, without any combination among them to obtain vertical and horizontal (E-W) components. It is important to obtain the 3D motion field in order to perform a correct interpretation of the observations, as well as an advanced model of the aquifer evolution, to be consider for sustainable management plans of groundwater resources and hazard assessments. With this objective, a GNSS network has been defined and two surveys have been carried out in November 2015 and July 2016. Despite the limited time interval covered by the surveys, the results allow us to obtain, for the first time, the regional 3D displacement field associated to the exploitation of the aquifer. These results, although in a preliminary form, confirm previous observations and suggest that the ad-hoc establishment of small GNSS networks represent a valuable technique for the spatio-temporal monitoring of the 3D displacement field of areas subjected to extensive groundwater extraction.Peer reviewe

    Long Term Ground Deformation in Volcanic Islands: Tenerife and La Palma, Canaries

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    Canary Islands form a volcanic archipelago with 7 major islands with a long-standing history of volcanic activity that began more than 40 million years ago More than a dozen eruptions have occurred on the islands of Tenerife, Lanzarote, and La Palma since the 16 th century. We used several geodetic techniques in order to achieve ground deformation on those islands. We propose that the measured deformation is directly related to gravitational sinking of the intrusive core the island into a weak lithosphere. We favour this thesis, relative to that of spreading, because neither the published data on the geology of Tenerife show evidence of compressional structures around the base of the island nor the GPS data indicate significant radial displacements, which would have been present in the case of spreading. In adition, given that the crust has been inflected under the mass of Tenerife, following Borgia (1994), we propose that the volcanic edifice is in a state of compression, which, in some volcanoes, has in the past been associated with hazardous explosive eruptions
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