1,174 research outputs found

    Chemistry of the older supracrustals of Archaean age around Sargur

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    In the Archaeans of the Karnataka craton two stratigraphically distinct volcano-sedimentary sequences occur, namely the older supracrustals of the Sargur type and the younger Dharwar greenstones. The dividing line between these is the 3 by old component of the Peninsular gneiss. The trace and rare earth element chemistry of the Sargur metasediments show, in general, marked similarity to the Archaean sediments. The significant departures are in the nickel and chromium abundances. The REE data of the Sargur pelites of the Terakanambi region represented by Silli-gt-bio-feldspar schists and paragneisses show LREE enrichment and flat to depleted HREE pattern. Banded iron formations have very low REE abundance. They show slightly enriched LREE and flat to depleted HREE pattern. REE abundance in the Mn-horizons is comparable to that of the Archaean sediments. Mn-horizons show enriched LREE and flat HREE with anamolous Eu. REE patterns of these bands is well evolved and has similarities with PAAS

    A transfer network linking Earth, Moon, and the triangular libration point regions in the Earth-Moon system

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    In the near future, several space applications in the Earth-Moon system may require a spacecraft to hold a stable motion, but the transfer trajectory infrastructure to access such stable motions has not been fully investigated yet. The triangular libration points, L 4and L5, in the Earth-Moon system have long been thought of as ideal locations for a communications satellite. Recently, Distant Retrograde Orbits (DROs) and Near-Rectilinear Halo Orbits (NRHOs) near the Moon have been identified as motion of interest for manned and unmanned missions with a focus on operations in cislunar space. The triangular libration points, as well as lunar DROs and NRHOs describe special types of possible motion for a spacecraft/satellite that is influenced solely by the gravitational fields of the Earth and the Moon. What is common to the tree types of solutions is that they are practically stable, that is, a spacecraft/satellite can naturally follow the solution for extended periods of time without requiring significant course adjustment maneuvers. This investigation contributes to the infrastructure of a network of transfer trajectories connecting regions of stability located near the Earth, Moon, and the triangular libration points in the Earth-Moon system. Several transfer options between regions of stability are presented and discussed, including transfer options between Low Earth Orbit (LEO) and lunar DRO, lunar DRO and periodic orbits near L4 and L5, as well as lunar DRO and L 2 NRHOs

    Corrección de dismetría femoral severa en el adulto mediante alargamiento y acortamiento contralateral: A propósito de un caso

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    Se presenta un caso de acortamiento femoral de 8 cm secundario a consolidación viciosa de fractura multifragmentaria femoral en un varón de 40 años. Debido a la edad del paciente y la magnitud de la dismetría, se decidió su corrección mediante un alargamiento progresivo de 4 cm del fémur corto y, en segundo tiempo, acortamiento inmediato de 4 cm del fémur largo mediante extirpación de un cilindro óseo que se implantó en la zona de distracción del fémur alargado. De esta manera se consiguió una corrección satisfactoria de la dismetría sin complicaciones reseñables. A pesar de la pérdida de estatura, pensamos que esta técnica debe ser considerada en casos puntuales de severa dismetría de extremidades inferior en el adulto.A case of 8-cm femoral shortening secondary to malunion of a multifragmented diaphyseal femoral fracture in 40 years old man is presented. Based on the age of the patients and the magnitude of the leg length discrepancy, treatment consisted of a first stage correction through progressive 4-cm lengthening of the shortened femur. In a second stage, shortening of the contralateral femur was performed by removal of a 4-cm diaphyseal bone cylinder that was implanted in the distraction area of the lengthened femur. The length discrepancy was corrected without complication. Although this technique implies a decrease of height, the method is suitable for selected cases of leg inequality affecting adults

    DeepZipper: A novel deep-learning architecture for lensed supernovae identification

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMLarge-scale astronomical surveys have the potential to capture data on large numbers of strongly gravitationally lensed supernovae (LSNe). To facilitate timely analysis and spectroscopic follow-up before the supernova fades, an LSN needs to be identified soon after it begins. To quickly identify LSNe in optical survey data sets, we designed ZipperNet, a multibranch deep neural network that combines convolutional layers (traditionally used for images) with long short-term memory layers (traditionally used for time series). We tested ZipperNet on the task of classifying objects from four categories - no lens, galaxy-galaxy lens, lensed Type-Ia supernova, lensed core-collapse supernova - within high-fidelity simulations of three cosmic survey data sets: the Dark Energy Survey, Rubin Observatory's Legacy Survey of Space and Time (LSST), and a Dark Energy Spectroscopic Instrument (DESI) imaging survey. Among our results, we find that for the LSST-like data set, ZipperNet classifies LSNe with a receiver operating characteristic area under the curve of 0.97, predicts the spectroscopic type of the lensed supernovae with 79% accuracy, and demonstrates similarly high performance for LSNe 1-2 epochs after first detection. We anticipate that a model like ZipperNet, which simultaneously incorporates spatial and temporal information, can play a significant role in the rapid identification of lensed transient systems in cosmic survey experiments. © 2022. The Author(s). Published by the American Astronomical Societ

    Sobre el tipo de metamorfismo regional progresvo hercínico en el Guadarrama oriental (Sistema central español)

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    Discusión sobre el tipo del metamorfismo regional progresivo hercínico del Guadarrama oriental. Se trata de un tipo intermedio de baja presión, con distena, muy parecido a los tipos que ya se conocen en Galicia, Portugal y Sur de la Península

    The hitchhiker’s guide to the galaxy catalog approach for Dark Siren gravitational-wave cosmology

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMWe outline the “dark siren” galaxy catalog method for cosmological inference using gravitational wave (GW) standard sirens, clarifying some common misconceptions in the implementation of this method. When a confident transient electromagnetic counterpart to a GW event is unavailable, the identification of a unique host galaxy is in general challenging. Instead, as originally proposed by Schutz, one can consult a galaxy catalog and implement a dark siren statistical approach incorporating all potential host galaxies within the localization volume. Trott & Huterer recently claimed that this approach results in a biased estimate of the Hubble constant, H 0, when implemented on mock data, even if optimistic assumptions are made. We demonstrate explicitly that, as previously shown by multiple independent groups, the dark siren statistical method leads to an unbiased posterior when the method is applied to the data correctly. We highlight common sources of error possible to make in the generation of mock data and implementation of the statistical framework, including the mismodeling of selection effects and inconsistent implementations of the Bayesian framework, which can lead to a spurious bia

    Multiport Multiband Decoupling Optimization for Miniature Antennas

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    Multiband multiport antennas are increasingly used for wireless communications and sensing miniature devices. The equations governing the multiport multiband antennas are analyzed in this paper with the objective of drawing the design guidelines for low coupling small antennas. Those guidelines have been applied in the design and optimization of a two-port dual band small antenna of size around λ0/13 x λ0/13 at the lowest frequency. Certain coupling conditions are applied to the port loads achieving a coupling reduction of 8 dB when having a simple two-element real load. A reduction of 27 dB can be obtained when having ideal loads composed by a higher number of elements. The antenna geometry is shown together with coupling minimization results
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