63 research outputs found

    The Palaeozoic basement of the Andean Frontal Cordillera at 34º S (Cordón del Carrizalito, Mendoza Province, Argentina): Geotectonic implications

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    The Cordón del Carrizalito is located in the southern sector of the Andean Frontal Cordillera. In this area, the Andean basement is composed of meta-sedimentary rocks (Las Lagunitas Formation) of Ordovician age. In addition, no- or very low grade metamorphism and less deformed rocks also occur in the study area. We call these rocks Selerpe series, whose characteristics are comparable to other series, late Carboniferous in age, described in nearby areas. The Las Lagunitas Formation is affected by west-verging folds, developed under low-grade metamorphic conditions. These structures can be attributed to the Chanic orogeny (Late Devonian – early Carboniferous). The Selerpe series and Las Lagunitas Formation are deformed by east-verging thrusts and folds developed in narrow bands and generated in the absence or under very low metamorphic conditions. These structures always deform the Chanic structures, and are attributed to the Gondwanan deformation (San Rafael orogeny, late Carboniferous – Permian in age). The Chanic structures of the study area can be placed in the western branch and in the hinterland of the Chanic orogen, which was developed as a result of the accretion of the Chilenia terrane at the west Gondwana margin during Late Devonian and early Carboniferous. The eastern branch of this orogen is located in the Andean Precordillera. The Permo-Triassic cover, deformed by the Andean orogenic cycle (Mesozoic – Cenozoic), rests unconformably on the Palaeozoic basement rocks.En el Cordón del Carrizalito, situado en el sector meridional de la Cordillera Frontal de los Andes, afloran metasedimentos ordovícicos pertenecientes a la Formación Las Lagunitas y otro conjunto de rocas menos deformadas, en ausencia de metamorfismo o con metamorfis­mo de muy bajo grado, que hemos denominado serie de Selerpe. Esta última es litoestratigráficamente comparable a series del Carbonífero superior descritas en áreas próximas. La Formación Las Lagunitas está afectada por pliegues apretados, vergentes al oeste y desarrollados bajo condiciones de metamorfismo de bajo grado. Estas estructuras pueden ser atribuidas a la orogenia Chánica (Devónico Superior - Car­bonífero inferior). La deformación Gondwánica, atribuida a la orogenia San Rafael, (Carbonífero superior – Pérmico), afecta tanto a la serie de Selerpe como a la Formación Las Lagunitas y se caracteriza por cabalgamientos y pliegues vergentes al este y generados en ausencia de metamorfismo o bajo condiciones metamórficas de muy grado bajo. Las estructuras chánicas de la zona estudiada se encuentran en las zonas internas de la rama occidental del orógeno del mismo nombre. Estas estructuras se desarrollaron como resultado de la acreción del terreno de Chilenia al margen occidental del antiguo continente de Gondwana durante el Devónico Superior – Carbonífero inferior. La rama oriental del orógeno Chánico se sitúa en la Precordillera andina. La cobertera permo-triásica, deformada durante el Mesozoico y Cenozoico por el ciclo orogénico Andino, se apoya discordantemente sobre las rocas del basamento paleozoico

    Origin and provenance of igneous clasts from late Palaeozoic conglomerate formations (Del Ratón and El Planchón) in the Andean Precordillera of San Juan, Argentina

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    Late Palaeozoic conglomerate formations (Del Ratón and El Planchón) from the Andean Precordillera (Argentina) were studied to unravel their age, composition and provenance. The conglomerates from the Del Ratón Formation are formed by igneous clasts of acid, intermediate and basic compositions (volcanic and plutonic). Laser Ablation (ICP-MS) zircon U-Pb study has yielded an age of 348±2 Ma (late Tournaisian) for the crystallization of a granitic clast, interpreted as a maximum deposition age for the Del Ratón Formation. Geochemistry of these clasts (high LILE/HFSE and La/Yb ratios, negative Nb-Ta anomalies) suggests a calc-alkaline batholithic source, probably located along the Andean Frontal Cordillera currently to the west, where similar calc-alkaline igneous rocks have been described. The El Planchón Formation overlies the Del Ratón Formation and, in the studied conglomerates, there are only igneous clasts of mafic composition (volcanic/subvolcanic). These mafic clasts have a very similar petrography and geochemistry to the Late Ordovician mafic igneous rocks of the Western Precordillera (low LILE/HFSE and La/Yb ratios, no negative Nb-Ta anomalies). Therefore we suggest that the El Planchón conglomerate clasts were probably delivered mainly from northern sources within the Precordillera terrane. This change in clast provenance is tentatively related to a shift in mountain uplift from the Frontal Cordillera (in the west) to the Precordillera (in the east) after the early Visean.Las formaciones conglomeráticas del Paleozoico superior (Del Ratón y El Planchón) de la Precordillera Andina (Argentina) fueron es­tudiadas con el fin de determinar su edad, composición y procedencia. Los conglomerados de la Formación Del Ratón están constituidos por clastos de rocas ígneas (volcánicas y plutónicas) ácidas, intermedias y básicas. Un estudio en circones con espectrometría de masas con plasma acoplado por inducción con ablación láser (LA-ICP-MS) proporciona una edad de 348±2 Ma (Tournaisiense superior) para la cristalización de un clasto granítico, que interpretamos como la máxima edad del depósito de la Formación Del Ratón. La geoquímica de los clastos (altas relaciones LILE/HFSE y La/Yb, anomalías negativas de Nb-Ta) sugiere que probablemente derivan de batolitos calcoal­calinos descritos en algunos sectores de la Cordillera Frontal Andina localizada actualmente al oeste. La Formación El Planchón se super­pone a la Formación Del Ratón y los clastos estudiados en los conglomerados de esta formación son únicamente de rocas ígneas básicas (subvolcánicas/volcánicas). Estos clastos tienen una petrografía y geoquímica similar a las rocas ígneas máficas del Ordovícico Superior de la Precordillera Occidental (bajas relaciones LILE/HFSE y La/Yb, ausencia de anomalías negativas en Nb-Ta). Por ello nosotros suge­rimos que los clastos de los conglomerados de la Formación El Planchón proceden de materiales localizados al norte dentro de la propia Precordillera. Este cambio en la procedencia de los clastos es tentativamente relacionado con una transferencia de la deformación desde la Cordillera Frontal (al oeste) a la Precordillera (al este), provocando el levantamiento de la Precordillera a partir del Viseense inferior

    The Historical Significance of the Welded Tuffs from Arucas, Canary Islands

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    [Abstract] Arucas Stone (Piedra de Arucas) is a welded tuff quarried in the town of Arucas, on the island of Gran Canaria in the Canary Archipelago. This rock has been quarried for centuries, not only for building but also for many other purposes, such as manufacturing water cisterns or conduits, and especially for carving. The quarrying and economic activity related to this stone have profoundly shaped the history and economy of the city of Arucas, in terms not only of extraction, but also of a highly valued local artisan tradition of stone carving. Immigrants from the Canary Islands even brought this stone to several countries in South America, where it was used to erect numerous important architectural heritage sites. Nowadays, this stone is only quarried in two areas, even though it is often required for the restoration and rehabilitation of historical buildings. Its special characteristics, and, above all, its historical importance, make this stone a prime candidate for Global Heritage Stone designation

    Light-driven motion of charged domain walls in isolated ferroelectrics

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    ©2022 American Physical SocietyLight-induced ferroelectric domain wall motion turns out to be a promising phenomenon to de- velop new photo-controlled devices. However, the physical origin of this ligh-matter coupling when material is irradiated with visible light remains unclear. Here, a phenomenological model predicting the motion of charged domain walls (CDWs) is developed. The photo-induced electronic reconstruc- tion mechanism is proposed as the primary absorption mechanism, leading to a linear dependence for the polarization perturbation with the light intensity. Domain walls motion is then driven by the energetic difference between domains in a CDW array, such that the macroscopic polarization can be easily tuned.Postprint (author's final draft

    Standard tests for the characterization of roofing slate pathologies

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    Las patologías que se originan en pizarra para cubiertas son debidas fundamentalmente a la presencia de materiales alterables (sulfuros de hierro, carbonatos y materia orgánica). Estos minerales pueden llegar a alterarse por efecto de los agentes medioambientales, una vez que la pizarra es puesta en obra. Las patologías están principalmente asociadas a procesos de oxidación y yesificación de las citadas fases minerales. En este trabajo se determinan las patologías potenciales de varias pizarras para cubiertas españolas, utilizando los ensayos definidos en las normas UNE-EN 12326:2005, 14147:2004 y 11597:2007.The pathologies formed in slate roofs are mainly due to the presence of potentially unstable minerals (iron sulfides, carbonates and organic matter). These minerals may become altered by the effect of environmental agents, once the slate roof is finished. The pathologies are mainly associated with oxidation and gypsification processes of the cited mineral phases. In this work, the potential pathologies of several Spanish roofing slates are identified, using the tests defined in the European Norms EN 12326:2005, 14147:2004 and 11597:2007.El presente trabajo se ha desarrollado en el marco del proyecto PERDURABLE: Durabilidad de materiales de piedra natural. Análisis y prevención de patologías. MICINN-09-CIT-380000-2009-25, financiado por el Ministerio de Ciencia e InnovaciónS

    Light-induced strain and its correlation with the optical absorption at charged domain walls in polycrystalline ferroelectrics

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    Photostrictive materials have a growing interest because of their great potential as light-driven actuators, among other optomechanical applications. In this context, the optical control of macroscopic strain in ferroelectrics has recently attracted remarkable attention as an effective alternative to the conventional electric control of strain. Here, a clear correlation between optical absorption and light-induced strain in polycrystalline BaTiO3 is shown. Specifically, the grain size and the sample thickness dependence of optical absorption when the material is irradiated with energy photons lower than the band gap evidence that light absorption at charged domain walls is the core of the observed photo-response in ferroelectrics. The photoinduced electronic reconstruction phenomenon is proposed as the primary physical mechanism for light absorption at charged domain walls. Results open a new pathway to designing ferroelectric-based devices with new functionalities like thickness gradient-based photo-controlled nanoactuators.Postprint (published version

    Orogenias paleozoicas en los Andes de Argentina y Chile y en la Península Antártica

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    Congreso Geológico Argentino (20º. 2017. San Miguel de Tucumán, Argentina). Simposio de Téctonica pre-andinaDurante el Neoproterozoico y Paleozoico, los Andes de Argentina y Chile, y desde fines del Paleozoico también la Península Antártica, formaron parte del margen SO de Gondwana. Durante este tiempo se acrecionaron a dicho margen varios fragmentos continentales de tamaño y aloctonía variable; denominados de N a S: Antofalla, Chi-Cu, Patagonia Occidental y Antártida Occidental. Estos fragmentos formaban parte de placas litosféricas, en ocasiones divididas en subplacas. La colisión de dichos fragmentos continentales con Gondwana y una última subducción bajo dicho margen, dieron lugar a 6 orogenias de extensión temporal y espacial limitada.Instituto Geológico y Minero de España, EspañaDepartamento de Geología, Universidad de Oviedo, EspañaUniversidad de Río Negro, ArgentinaServicio Geológico y Minero Argentino, ArgentinaInstituto De Bio y Geociencias Del NOA, Consejo Nacional de Investigaciones Científicas y Técnicas, ArgentinaInstituto De Bio y Geociencias Del NOA, Universidad Nacional de Salta, ArgentinaDepartamento de Geodinámica, Universidad del País Vasco, EspañaFacultad de Geología, Universidad de Barcelona, EspañaDepartamento de Geología, Universidad de Chile, ChileUniversidad Andrés Bello, ChileUnidad de Tectónica, Consejo Nacional de Investigaciones Científicas y Técnicas, ArgentinaFacultad de Geología, Universidad de Buenos Aires, ArgentinaÁrea de Geología, Universidad Rey Juan Carlos, EspañaUniversidad de Salta, ArgentinaInstituto de Investigación en Paleobiología y Geología, Universidad de Río Negro, ArgentinaInstituto de Investigación en Paleobiología y Geología, Consejo Nacional de Investigaciones Científicas y Técnicas, ArgentinaCentro de Investigaciones Geológicas, Universidad de La Plata, ArgentinaUniversidad de San Juan, ArgentinaPeer reviewe

    Cardiovascular events in Systemic Lupus Erythematosus: a nationwide study in Spain from the RELESSER Registry

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    This article estimates the frequency of cardiovascular (CV) events that occurred after diagnosis in a large Spanish cohort of patients with systemic lupus erythematosus (SLE) and investigates the main risk factors for atherosclerosis. RELESSER is a nationwide multicenter, hospital-based registry of SLE patients. This is a cross-sectional study. Demographic and clinical variables, the presence of traditional risk factors, and CV events were collected. A CV event was defined as a myocardial infarction, angina, stroke, and/or peripheral artery disease. Multiple logistic regression analysis was performed to investigate the possible risk factors for atherosclerosis. From 2011 to 2012, 3658 SLE patients were enrolled. Of these, 374 (10.9%) patients suffered at least a CV event. In 269 (7.4%) patients, the CV events occurred after SLE diagnosis (86.2% women, median [interquartile range] age 54.9 years [43.2-66.1], and SLE duration of 212.0 months [120.8-289.0]). Strokes (5.7%) were the most frequent CV event, followed by ischemic heart disease (3.8%) and peripheral artery disease (2.2%). Multivariate analysis identified age (odds ratio [95% confidence interval], 1.03 [1.02-1.04]), hypertension (1.71 [1.20-2.44]), smoking (1.48 [1.06-2.07]), diabetes (2.2 [1.32-3.74]), dyslipidemia (2.18 [1.54-3.09]), neurolupus (2.42 [1.56-3.75]), valvulopathy (2.44 [1.34-4.26]), serositis (1.54 [1.09-2.18]), antiphospholipid antibodies (1.57 [1.13-2.17]), low complement (1.81 [1.12-2.93]), and azathioprine (1.47 [1.04-2.07]) as risk factors for CV events. We have confirmed that SLE patients suffer a high prevalence of premature CV disease. Both traditional and nontraditional risk factors contribute to this higher prevalence. Although it needs to be verified with future studies, our study also shows-for the first time-an association between diabetes and CV events in SLE patients

    Delirios juveniles: expresiones creativas de futuros escritores

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    Los cuentos de la presente compilación son el resultado de la creatividad de los jóvenes estudiantes de la UPS-Cuenca. Once relatos cortos que inventan una gran diversidad de mundos posibles, cuyos autores usan tonos y registros muy particulares para representarlos. Si algo guardan en común estas narraciones, es que los autores intentan diluir la línea que separa la fantasía de la realidad, algo muy propio de la naturaleza narrativa que envuelve a ecuatorianos y latinoamericanos. Crímenes sin resolver, fantasmas que atormentan a los vivos desde el pasado, bucles temporales, casualidades oportunas/inoportunas, amores prohibidos, complots familiares, fantasías de personajes que no soportan la realidad y la crónica de un fallecimiento, son algunos de los temas que recorren los cuentos de este libro. Más allá de los criterios canónicos, estos textos son el debut de jóvenes creadores ecuatorianos convencidos de su esfuerzo literario, y serán para el lector, un respiro a sus preocupaciones cotidianas

    European beech stem diameter grows better in mixed than in mono-specific stands at the edge of its distribution in mountain forests

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    Recent studies show that several tree species are spreading to higher latitudes and elevations due to climate change. European beech, presently dominating from the colline to the subalpine vegetation belt, is already present in upper montane subalpine forests and has a high potential to further advance to higher elevations in European mountain forests, where the temperature is predicted to further increase in the near future. Although essential for adaptive silviculture, it remains unknown whether the upward shift of beech could be assisted when it is mixed with Norway spruce or silver fir compared with mono-specific stands, as the species interactions under such conditions are hardly known. In this study, we posed the general hypotheses that the growth depending on age of European beech in mountain forests was similar in mono-specific and mixed-species stands and remained stable over time and space in the last two centuries. The scrutiny of these hypotheses was based on increment coring of 1240 dominant beech trees in 45 plots in mono-specific stands of beech and in 46 mixed mountain forests. We found that (i) on average, mean tree diameter increased linearly with age. The age trend was linear in both forest types, but the slope of the age–growth relationship was higher in mono-specific than in mixed mountain forests. (ii) Beech growth in mono-specific stands was stronger reduced with increasing elevation than that in mixed-species stands. (iii) Beech growth in mono-specific stands was on average higher than beech growth in mixed stands. However, at elevations > 1200 m, growth of beech in mixed stands was higher than that in mono-specific stands. Differences in the growth patterns among elevation zones are less pronounced now than in the past, in both mono-specific and mixed stands. As the higher and longer persisting growth rates extend the flexibility of suitable ages or size for tree harvest and removal, the longer-lasting growth may be of special relevance for multi-aged silviculture concepts. On top of their function for structure and habitat improvement, the remaining old trees may grow more in mass and value than assumed so far.The authors would like to acknowledge networking support by the COST (European Cooperation in Science and Technology) Action CLIMO (Climate-Smart Forestry in Mountain Regions—CA15226) financially supported by the EU Framework Programme for Research and Innovation HORIZON 2020. This publication is part of a project that has received funding from the European Union’s HORIZON 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No 778322. Thanks are also due to the European Union for funding the project ‘Mixed species forest management. Lowering risk, increasing resilience (REFORM)’ (# 2816ERA02S under the framework of Sumforest ERA-Net). Further, we would like to thank the Bayerische Staatsforsten (BaySF) for providing the observational plots and to the Bavarian State Ministry of Food, Agriculture, and Forestry for permanent support of the Project W 07 ‘Long-term experimental plots for forest growth and yield research’ (#7831-26625-2017). We also thank the Forest Research Institute, ERTI Sárvár, Hungary, for assistance and for providing observational plots. Furthermore, our work was partially supported by the SRDA via Project No. APVV-16-0325 and APVV-15-0265, the Ministry of Science and Higher Education of the Republic of Poland, the Project “EVA4.0” No. CZ.02.1.01/0.0/0.0/16_019/0000803 funded by OP RDE and the Project J4-1765 funded by the Slovenian Research Agency and also by the Bulgarian National Science Fund (BNSF) and the Project No. DCOST 01/3/19.10.2018
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