302 research outputs found
Railway deformation detected by DInSAR over active sinkholes in the Ebro Valley evaporite karst, Spain
Subsidence was measured for the first time on railway tracks in the central sector of Ebro Valley (NE Spain) using Differential Synthetic Aperture Radar Interferometry (DInSAR) techniques. This area is affected by evaporite karst and the analysed railway corridors traverse active sinkholes that produce deformations in these infrastructures. One of the railway tracks affected by slight settlements is the Madrid-Barcelona high-speed line, a form of transport infrastructure highly vulnerable to ground deformation processes. Our analysis based on DInSAR measurements and geomorphological surveys indicates that this line shows dissolution-induced subsidence and compaction of anthropogenic deposits (infills and embankments). Significant sinkhole-related subsidence was also measured by DInSAR techniques on the Castejón-Zaragoza conventional railway line. This study demonstrates that DInSAR velocity maps, coupled with detailed geomorphological surveys, may help in the identification of the railway track sections that are affected by active subsidence
Ratio between inbreeding and coancestry rates as a measure of population subdivision. Preliminary results
Ponencia publicada en ITEA, vol. 104Uno de los factores que provocan incrementos de consanguinidad superiores a los que se esperarían
en función del tamaño de la población es la subdivisión de las poblaciones. La medida de la subdivisión
de poblaciones no resulta sencilla. Se presenta una medida de subdivisión de poblaciones que se
obtiene a partir de la información de pedigree. Se basa en la comparación directa de los incrementos
de coascendencia en relación a los incrementos de endogamia por generación discreta equivalente,
establecidos ambos a partir de la media de valores individuales de esos parámetros. La utilidad del
parámetro desde el punto de vista descriptivo se ilustra con la ayuda de una población simulada y de
dos poblaciones reales con diferentes escenarios de subdivisión.Subdivision is one of the factors leading to increase in inbreeding higher than those expected
regarding population size. Measuring population subdivision is not straightforward given that it is
established rather diffuse. A measure of population subdivision from pedigrees is presented. It is
based on the direct comparison of the increases in coancestry and the increases in inbreeding
computed over equivalent discrete generation. Coancestry and inbreeding rates were established
from the average of individual values of those parameters. The usefulness of the new parameter
from a descriptive point of view is illustrated using a simulated population and two real populations
with an opposed scenario regarding subdivision
Evaluating Quaternary activity versus inactivity on faults and folds using geomorphological mapping and trenching: Seismic hazard implications
The incorporation of active faults in seismic hazard analyses may have a significant impact on the feasibility, design and cost of major engineering projects (e.g., nuclear facilities, dams), especially when located in the site vicinity. The regulatory definition of active versus inactive fault is generally based on whether the fault has ruptured or not after a specific chronological bound (i.e. fault recency). This work presents a methodology, mainly based on geomorphological mapping and trenching, for determining whether specific faults can be considered as active or inactive. The approach is illustrated through the analysis of several faults located in the Spanish Pyrenees (Loiti, Leyre, La Trinidad, Ruesta faults). The 29 km long Loiti Thrust was included in the Neotectonic Map of Spain as a probable neotectonic structure. Previous works, based on geomorphological investigations, incorporated the 28 km long Leyre Thrust as a significant seismic source in a probabilistic seismic hazard analysis, which challenged the seismic design of nearby large dams. The production of detailed geomorphological strip maps along the faults allowed the recognition of specific sites where the faults are covered by Quaternary deposits. The establishment of chronosequences (pediments-terrace sequences)and the available geochronological data helped identifying the most adequate morpho-stratigraphic units for satisfactorily evaluating fault activity vs. inactivity. The excavation of trenches at the selected sites provided unambiguous information on the presence or lack of deformation in the Quaternary cover overlying the fault, and the origin of scarps (tectonic versus erosional). Trenches were also useful for collecting samples and reliably measuring the relative height of terraces overlain by thick colluvium. The evidence gathered by these methods were complemented with the numerical dating of non-deformed slope deposits covering a fault, the analysis of the longitudinal profiles of old pediment surfaces located in the proximity of a fault, the examination of a cave situated next to a fault searching for speleoseismological evidence, and regional geodetic and seismotectonic data (GPS measurements, earthquake focal mechanisms). The integration of all the data, and especially the trenches dug in non-deformed old terrace deposits (>100 ka)truncating the faults, indicates that the analysed faults can be considered inactive and that previous neotectonic postulations were based on non-valid geomorphological interpretations
Diseño optimizado y caracterización de hormigones autocompactantes reforzados con fibra polimérica de alto módulo
Los hormigones autocompactantes suponen una alternativa de ejecución fácil y rápida, que garantiza una puesta en obra de calidad y una mejora de las prestaciones mecánicas a igualdad de contenido de cemento. Por otro lado, los hormigones reforzados con fibra de carácter estructural son cada vez más demandados ya que, en el caso de contar con el tipo y proporción de fibra adecuado, permiten la sustitución total o parcial del armado convencional de acero. Este estudio persigue el diseño optimizado de hormigones autocompactantes reforzados con fibra polimérica de alto módulo para la ejecución de obras de rehabilitación, como las llevadas a cabo en las bóvedas de la catedral de San Cristóbal de la Laguna, de tal manera que, manteniendo la característica de autocompactabilidad y sin perjuicio de la durabilidad, dicho hormigón presente un comportamiento post-fisuración que cumpla con las especificaciones del Anejo 14 de la EHE-08, en lo que se refiere a los valores mínimos de resistencia característica residual a tracción por flexión fR,1,k y fR,3,k , de tal forma que la fibra alcance la consideración de estructural, lo que supondría una alternativa técnica al refuerzo con fibra de acero que permitiría la sustitución parcial o total de la armadura de acero
Polypropylene fiber-reinforced self-compacting concrete for the reconstruction of the cathedral of La Laguna, Canary Island, Spain
High performance materials are needed for the reconstruction of such a singular building as a cathedral, since in addition to special mechanical properties, high self compact ability, high durability and high surface quality, are specified. Because of the project’s specifications, the use of polypropylene fiber-reinforced, self-compacting concrete was selected by the engineering office. The low quality of local materials and the lack of experience in applying macro polypropylene fiber for structural reinforcement with these components materials required the development of a pretesting program. To optimize the mix design, performance was evaluated following technical, economical and constructability criteria. Since the addition of fibers reduces concrete self-compactability, many trials were run to determine the optimal mix proportions. The variables introduced were paste volume; the aggregate skeleton of two or three fractions plus limestone filler; fiber type and dosage. Two mix designs were selected from the preliminary results. The first one was used as reference for self-compactability and mechanical properties. The second one was an optimized mix with a reduction in cement content of 20 kg/m3and fiber dosage of 1 kg/m3. For these mix designs, extended testing was carried out to measure the compression and flexural strength, modulus of elasticity, toughness, and water permeability resistanc
Genetic differentiation between two geographic subpopulations of Bermeya goat
Ponencia publicada en ITEA, vol.104Este trabajo es un análisis preliminar de la diversidad y grado de diferenciación genética entre las subpoblaciones
Oriental y Occidental de la cabra de raza Bermeya de Asturias. Se han genotipado 27
microsatélites en 122 individuos pertenecientes a las poblaciones de cabra Bermeya Oriental, Bermeya
Occidental, del Guadarrama, Alpine y Saanen. Las poblaciones de raza Bermeya presentaron heterocigosis
esperadas menores de 0,6 y coascendencias moleculares dentro de población de 0,419, reflejando
una alta identidad genética entre individuos. Asimismo, el número medio de alelos por locus, ajustado
por el tamaño muestral, de las poblaciones Bermeya Oriental y Occidental fueron los menores
encontrados (3,8 y 3,9, respectivamente). La mayor coascendencia molecular se encontró entre las
poblaciones Bermeya Oriental-Guadarrama (0,388 ± 0,006), como consecuencia de la introgresión, en
el Oriente asturiano de individuos de tipo Pirenáico. Este parámetro entre las poblaciones de Bermeya
Oriental y Occidental fue de 0,371 ± 0,007. Puede ser necesario establecer estrategias de conservación
diferenciadas para las dos poblaciones geográficas de cabra Bermeya.Two geographic subpopulations (Eastern and Western) of the Asturian Bermeya goat were analysed
using 27 microsatellites. A total of 122 individuals of Bermeya, Guadarrama, Alpine and Saanen goat
breeds were genotyped. The Eastern and Western Bermeya subpopulations had expected
heterozygosity values lower than 0.6 and within-subpopulations molecular coancestry values of 0.419,
thus illustrating a high between individuals genetic identity. The rarefacted average number of alleles
per locus found in both the Eastern and the Western Bermeya subpopulations were the lowest in the
dataset (3.8 and 3.9, respectively). The higher between-populations molecular coancestry values was
found for the pair Eastern Bermeya-Guadarrama (0.388 ± 0.006), thus reflecting the introgression of
the Pyrenean-type goat into Eastern Asturias. This parameter between the two Bermeya
subpopulations was of 0.371 ± 0.007. It could be recommended the implementation of different
conservation strategies for each of the geographic subpopulations of Bermeya goat
Salinity tolerance as a factor controlling spatial patterns in composition and structure of zooplankton in the Guadalquivir estuary
Trabajo presentado en ECSA 56 (Coastal systems in transition: From a 'natural' to an 'anthropogenically-modified' state), celebrado en Bremen del 4 al 7 de septiembre de 2016.N
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