2,357 research outputs found

    A synthesis of palynological data from the Lower Permian Cerro Pelado Formation (Parana Basin, Uruguay): A record of warmer climate stages during Gondwana glaciations

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    This paper presents a synthesis of the palynological record in the Cerro Pelado Formation deposits (Lower Permian, Paraná basin, Cerro Largo Department, north-eastern Uruguay) based on pre-existing data and new findings. The successions studied in this formation consist mainly of non-marine to glacial-marine mudstones and sandy mudstones. The palynological assemblages yielded by 32 samples collected from two outcrops and thirty borehole samples demonstrate that not significant floral changes took place through the considered stratigraphic range. The correlation of these assemblages with biostratigraphic palynozones, proposed previously for the Paraná/Chacoparaná Basin of Brazil, Argentina and Uruguay point to their Early Permian age. The most widespread spore genera in these assemblages are Punctatisporites, Lundbladispora, Vallatisporites and Granulatisporites. Among pollen grains, Caheniasaccites, Vittatina, Potonieisporites, Protohaploxypinus and Plicatipollenites are the most representative. Palynomorphs assigned to Chlorophyta, Prasinophyta, and acritarchs indicate the development of brackish to fresh water lacustrine environments. The results from the facies and palynological analyses suggest that these deposits were formed during interglacial or postglacial warmer climatic episodes. This fact would agree well with the proposal that Gondwana glaciations were characterized by discrete glacial phases (with multiple glacial lobe advance-retreat phases) alternating with warmer climatic episodes. These episodes could be recognized thanks to sub-glacial and melt water related continental deposits that would bear characteristic palynological assemblages, like the recorded in the Cerro Pelado Fm. successions

    A synthesis of palynological data from the Lower Permian Cerro Pelado Formation (Paraná Basin, Uruguay): A record of warmer climate stages during Gondwana glaciations

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    This paper presents a synthesis of the palynological record in the Cerro Pelado Formation deposits (Lower Permian, Paraná basin, Cerro Largo Department, north eastern Uruguay) based on pre-existing data and new findings. The successions studied in this formation consist mainly of non-marine to glacial-marine mudstones and sandy mudstones. The palynological assemblages yielded by 32 samples collected from two outcrops and thirty borehole samples demonstrate that not significant floral changes took place through the considered stratigraphic range. The correlation of these assemblages with biostratigraphic palynozones, proposed previously for the Paraná/ Chacoparaná Basin of Brazil, Argentina and Uruguay point to their Early Permian age. The most widespread spore genera in these assemblages are Punctatisporites, Lundbladispora, Vallatisporites and Granulatisporites. Among pollen grains, Caheniasaccites, Vittatina, Potonieisporites, Protohaploxypinus and Plicatipollenites are the most representative. Palynomorphs assigned to Chlorophyta, Prasinophyta, and acritarchs indicate the development of brackish to fresh water lacustrine environments. The results from the facies and palynological analyses suggest that these deposits were formed during interglacial or postglacial warmer climatic episodes. This fact would agree well with the proposal that Gondwana glaciations were characterized by discrete glacial phases (with multiple glacial lobe advance-retreat phases) alternating with warmer climatic episodes. These episodes could be recognized thanks to sub-glacial and melt water related continental deposits that would bear characteristic palynological assemblages, like the recorded in the Cerro Pelado Fm. successions

    Size effects on the Neél temperature of antiferromagnetic NiO nanoparticles

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    Among all antiferromagnetic transition metal monoxides, NiO presents the highest Neél temperature (TN ~ 525 K). In this work, the size-dependent reduction of TN in NiO nanoparticles with average diameters (D) ranging from 4 to 9 nm is investigated by neutron diffraction. The scaling law followed by TN(D) is in agreement with the Binder theory of critical phenomena in low-dimensional systems. X-ray absorption fine structure measurements link the decrease of TN to the occurrence of size effects (average undercoordination, bond relaxation and static disorder) in the nearest and next-nearest Ni coordination shells that hold the key for the maintenance of the antiferromagnetic order

    Aplicación de técnicas avanzadas de interferometría diferencial SAR para la detección de deformaciones del terreno en Madrid

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    El uso de técnicas avanzadas de interferometría diferencial en un conjunto de imágenes SAR permite la detección de movimientos en el terreno con mayor precisión que las técnicas clásicas. En este documento se presentan los resultados de aplicar una de estas técnicas avanzadas en la ciudad de Madrid, donde ha sido detectada una deformación del terreno asociada a la variación del nivel de agua del acuífero detrítico del Terciario.The advanced Differential INterferometry SAR (DInSAR) techniques are able to detect terrain deformations more accurately than classic DInSAR ones. In this paper, the results obtained with one of this advanced techniques in Madrid city are presented, where an up-down movement has been detected and associated to the water level variation in the aquifer located under Madrid city

    Internet of things (IoT) as sustainable development goals (SDG) enabling technology towards smart readiness indicators (SRI) for university buildings

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    Non-residential buildings contribute to around 20% of the total energy consumed in Europe. This consumption continues to increase globally. Smart building proposals (focused on Nearly Zero Energy Building (NZEB), air quality monitoring, energy saving with thermal comfort, etc.) were already necessary before 2020, and the pandemic has made this research and development area more essential. Furthermore, the need to meet the Sustainable Development Goals (SDG) and obtain technological solutions based on the Internet of Things (IoT) requires holistic contributions through real installations that serve as spaces for measuring, testing, study and research. This article proposes a “measure–analyse–decide and act” methodology to quantify the Smart Readiness Indicator (SRI) for university buildings as a reference environment for energy efficiency and COVID-19 prevention models. Two conceptual spaces (physical and digital) within two dimensions (users and infrastructures) are designated over an IoT three-level model (information acquisition, interoperable communication, and data-driven decision). An IoT ecosystem (sensoriZAR) was implemented as a proof-of-concept of a smart campus at the University of Zaragoza, Spain. Focused on CO2 and energy consumption monitoring, the results showed effectiveness through real installations, demonstrating the IoT potential as SDG-enabling technologies. These contributions allow not only experimental lab tests (from the authors’ expertise in several specialties of Industrial, Mechanical, Design, Thermal, Electrical, Electronic, Computer and Telecommunication Engineering) but also a reference model for direct application in academic works, research projects and institutional initiatives, extendable to professional environments, buildings and cities. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

    High-temperature anti-Invar behavior of gamma-Fe precipitates in Fe_xCu_(100-x) solid solutions: Ferromagnetic phases

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    High-temperature magnetization and neutron diffraction measurements on metastable Fe_xCu_(100-x) solid solutions have recently shown to imply that γ-Fe precipitates present ferromagnetic anti-Invar behavior. For this reason, we have studied the ferromagnetic phases of γ-Fe in moment-volume parameter space, using the general potential linearized-augmented plane-wave method and the fixed spin moment procedure in order to calculate the corresponding total energy. We find that only two ferromagnetic phases (one related to a low- spin state and the other to a high-spin state) can exist and even coexist in limited volume ranges (3.55-3.59 Å). Hence, our results provide a "revisited" version of the local spin density calculations used in the early article by Moruzzi [Phys. Rev. B 34, 1784 (1986)]. In addition, the fixed spin moment method-using an energy-moment-volume space representation-allows us to conclude that the high-spin state is the ground state of the gamma-Fe precipitates, as the anti-Invar behavior is an intrinsic property of these states. This simple scenario seems to adequately describe the perplexing phenomenology recently observed on Fe_xCu_(100-x) solid solutions

    Pie de Charcot. Cuando menos es más.

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    Paciente diabética de 71 años de edad, insulino-dependiente, obesa e hipertensa con mal con - trol metabólico que presentó una fractura de tobillo y una luxación subastragalina. Inicialmente fue tratada en su hospital con tracción transesquelética durante varias semanas que resultó infructuosa, evolucionando a una desestructuración completa del retropié y a una úlcera profunda y tórpida, al iniciar la marcha la paciente.Con este escenario acude la paciente a nuestras consultas, tras dos años de evolución, para valorar alternativas a la amputación.A 71-years-old female, diabetic pacient insulin-dependent, obese with high blood pressure and poor metabolic control suffered an ankle fracture and a subtalar dislocation. At the beginning skeletal traction was applied at her Institution but result was unsuccessful, so a complete breakdown of the hindfoot and a deep and torpid ulcer developed. Facing this scenario the patient came to our clinic, after two years of evolution, to assess alternatives to amputation

    Ecological, genetic and evolutionary drivers of regional genetic differentiation in Arabidopsis thaliana

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    Background: Disentangling the drivers of genetic differentiation is one of the cornerstones in evolution. This is because genetic diversity, and the way in which it is partitioned within and among populations across space, is an important asset for the ability of populations to adapt and persist in changing environments. We tested three major hypotheses accounting for genetic differentiation—isolation-by-distance (IBD), isolation-by-environment (IBE) and isolation-by-resistance (IBR)—in the annual plant Arabidopsis thaliana across the Iberian Peninsula, the region with the largest genomic diversity. To that end, we sampled, genotyped with genome-wide SNPs, and analyzed 1772 individuals from 278 populations distributed across the Iberian Peninsula. Results: IBD, and to a lesser extent IBE, were the most important drivers of genetic differentiation in A. thaliana. In other words, dispersal limitation, genetic drift, and to a lesser extent local adaptation to environmental gradients, accounted for the within- and among-population distribution of genetic diversity. Analyses applied to the four Iberian genetic clusters, which represent the joint outcome of the long demographic and adaptive history of the species in the region, showed similar results except for one cluster, in which IBR (a function of landscape heterogeneity) was the most important driver of genetic differentiation. Using spatial hierarchical Bayesian models, we found that precipitation seasonality and topsoil pH chiefly accounted for the geographic distribution of genetic diversity in Iberian A. thaliana. Conclusions: Overall, the interplay between the influence of precipitation seasonality on genetic diversity and the effect of restricted dispersal and genetic drift on genetic differentiation emerges as the major forces underlying the evolutionary trajectory of Iberian A. thaliana

    Moving Magnetic Features around a Pore

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    Spectropolarimetric observations from Sunrise II/IMaX obtained in June 2013 are used for a statistical analysis to determine the physical properties of moving magnetic features (MMFs) observed near a pore. MMFs of the same and opposite polarity with respect to the pore are found to stream from its border at an average speed of 1.3 km s1^{-1} and 1.2 km s1^{-1} respectively, with mainly same-polarity MMFs found further away from the pore. MMFs of both polarities are found to harbor rather weak, inclined magnetic fields. Opposite-polarity MMFs are blue-shifted, while same-polarity MMFs do not show any preference for up- or downflows. Most of the MMFs are found to be of sub-arcsecond size and carry a mean flux of \sim 1.2×1017\times 10^{17} Mx.Comment: 8 pages, 4 figures, accepted for publication in ApJ

    Maximum Entropy Limit of Small-scale Magnetic Field Fluctuations in the Quiet Sun

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    The observed magnetic field on the solar surface is characterized by a very complex spatial and temporal behavior. Although feature-tracking algorithms have allowed us to deepen our understanding of this behavior, subjectivity plays an important role in the identification and tracking of such features. In this paper, we continue studies Gorobets, A. Y., Borrero, J. M., & Berdyugina, S. 2016, ApJL, 825, L18 of the temporal stochasticity of the magnetic field on the solar surface without relying either on the concept of magnetic features or on subjective assumptions about their identification and interaction. We propose a data analysis method to quantify fluctuations of the line-of-sight magnetic field by means of reducing the temporal field's evolution to the regular Markov process. We build a representative model of fluctuations converging to the unique stationary (equilibrium) distribution in the long time limit with maximum entropy. We obtained different rates of convergence to the equilibrium at fixed noise cutoff for two sets of data. This indicates a strong influence of the data spatial resolution and mixing-polarity fluctuations on the relaxation process. The analysis is applied to observations of magnetic fields of the relatively quiet areas around an active region carried out during the second flight of the Sunrise/IMaX and quiet Sun areas at the disk center from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory satellite.Comment: 11 pages, 5 figures, The Astrophysical Journal Supplement Series (accepted
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