10,724 research outputs found

    SIR-A imagery in geologic studies of the Sierra Madre Oriental, northeastern Mexico. Part 1 (Regional stratigraphy): The use of morphostratigraphic units in remote sensing mapping

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    SIR-A imaging was used in geological studies of sedimentary terrains in the Sierra Madre Oriental, northeastern Mexico. Geological features such as regional strike and dip, bedding, folding and faulting were readily detected on the image. The recognition of morphostructural units in the imagery, coupled with field verification, enabled geological mapping of the region at the scale of 1:250 000. Structural profiling lead to the elaboration of a morphostructural map allowing the recognition of an echelon folds and field trends which were used to postulate the ectonic setting of the region

    Regulation of transforming growth factor-beta 1 gene expression by glucocorticoids in normal human T lymphocytes.

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    Glucocorticoids (GC) modulate immune function in a number of ways, including suppression of T cell proliferation and other IL-2-mediated T cell functions. These inhibitory effects are similar to those induced by transforming growth factor-beta 1 (TGF-beta 1), a cytokine with potent T cell inhibiting activities. We examined the hypothesis that GC effects may be at least partially achieved through modulation of the expression of the TGF-beta 1 gene in activated T cells. Normal T cells were cultured with or without purified phytohemagglutinin (PHA-p) and 4 beta-phorbol 12-myristate 13-acetate (PMA) in the presence or absence of the synthetic GC, dexamethasone (100-200 micrograms/ml). The production of latent and active forms of TGF beta by these cells were analyzed by immunoblotting and bioassays. The steady-state levels of TGF-beta 1 mRNA were analyzed in total RNA from these cells by Northern hybridizations using a human TGF-beta 1 cDNA. The results showed that dexamethasone caused an increase in TGF beta production and a dose-dependent two to fourfold increase in TGF-beta 1 mRNA in activated as well as in unstimulated T cells, 1 h after exposure of the cultures to the steroid. The increase in TGF-beta 1 mRNA levels by dexamethasone was further potentiated two to threefold by cycloheximide, suggesting that the steroid effect may be due to inhibition of the synthesis of proteins that decrease TGF-beta 1 gene transcription or the stability of its transcripts. Finally, in vitro nuclear transcription studies indicated the dexamethasone effects on TGF-beta 1 gene expression to be largely transcriptional

    An Adaptive Sampling Scheme to Efficiently Train Fully Convolutional Networks for Semantic Segmentation

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    Deep convolutional neural networks (CNNs) have shown excellent performance in object recognition tasks and dense classification problems such as semantic segmentation. However, training deep neural networks on large and sparse datasets is still challenging and can require large amounts of computation and memory. In this work, we address the task of performing semantic segmentation on large data sets, such as three-dimensional medical images. We propose an adaptive sampling scheme that uses a-posterior error maps, generated throughout training, to focus sampling on difficult regions, resulting in improved learning. Our contribution is threefold: 1) We give a detailed description of the proposed sampling algorithm to speed up and improve learning performance on large images. We propose a deep dual path CNN that captures information at fine and coarse scales, resulting in a network with a large field of view and high resolution outputs. We show that our method is able to attain new state-of-the-art results on the VISCERAL Anatomy benchmark

    Charged-current inclusive neutrino cross sections in the SuperScaling model including quasielastic, pion production and meson-exchange contributions

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    Charged current inclusive neutrino-nucleus cross sections are evaluated using the superscaling model for quasielastic scattering and its extension to the pion production region. The contribution of two-particle-two-hole vector meson-exchange current excitations is also considered within a fully relativistic model tested against electron scattering data. The results are compared with the inclusive neutrino-nucleus data from the T2K and SciBooNE experiments. For experiments where ⟨Eν⟩∼0.8\langle E_\nu \rangle \sim 0.8 GeV, the three mechanisms considered in this work provide good agreement with the data. However, when the neutrino energy is larger, effects from beyond the Δ\Delta also appear to be playing a role. The results show that processes induced by two-body currents play a minor role at the kinematics considered.Comment: 10 pages, 7 figure

    Annotating Medical Image Data

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    Aplicación de nuevas técnicas docentes en la asignatura Sistemas Cliente/Servidor

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    En este trabajo mostramos nuestras experiencias en la aplicación de metodologías de aprendizaje cooperativo y basado en proyectos en la asignatura Sistemas Cliente/Servidor en los cursos académicos 2008/2009 y 2009/2010.SUMMARY: In this work we present our teaching experience in the aplication of cooperative and project-based learning methodologies within the subject Client/Server Systems in the academic years 2008/2009 and 2009/2010.Peer Reviewe

    Linear second-order differential equations for barotropic FRW cosmologies

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    "Simple linear second-order differential equations have been written down for FRW cosmologies with barotropic fluids by Faraoni. His results have been extended by Rosu, who employed techniques belonging to nonrelativistic supersymmetry to obtain time-dependent adiabatic indices. Further extensions are presented here using the known connection between the linear second-order differential equations and Dirac-like equations in the same supersymmetric context. These extensions are equivalent to adding an imaginary part to the adiabatic index which is proportional to the mass parameter of the Dirac spinor. The natural physical interpretation of the imaginary part is related to the particular dissipation and instabilities of the barotropic FRW hydrodynamics that are introduced by means of this supersymmetric scheme.

    Two Cyclocoelids from the Lesser Yellowlegs, Tringa flavipes (Scolopacidae), from the Central Flyway of North America, Including the Description of Haematotrephus selfi n. sp. (Digenea: Cyclocoelidae)

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    Seven specimens of cyclocoelids (6 specimens representing Haematotrephus selfi n. sp. and 1 specimen representing a second unidentified species of Haematotrephus) collected by the late Dr. J. Teague Self, former professor, Department of Zoology, University of Oklahoma, Norman, Oklahoma, U.S.A., from the body cavities of 3 lesser yellowlegs, Tringa flavipes, (2 birds collected from Roger Mills County, Oklahoma on 23 and 29 August 1963, and 1 collected from Manitoba, Canada on 3 June 1964) and deposited in the Manter Laboratory of Parasitology, University of Nebraska, Lincoln, Nebraska are described. Haematotrephus selfi n. sp. can be distinguished from all other species in the genus that lack an oral sucker except Haematotrephus limnodromi by having intertesticular uterine loops. It most closely resembles H. limnodromi but differs from it by having a smaller body, a smaller pharynx, smaller testes, a shorter cirrus sac, and somewhat smaller eggs. In addition, H. selfi n. sp. lacks a uterine seminal receptacle

    Atmospheric Condensed-Phase Reactions of Glyoxal with Methylamine

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    [1] Glyoxal reacts with methylamine in drying cloud droplet/aerosol surrogates to form high molecular mass oligomers along with smaller amounts of 1,3-dimethylimidazole and light-absorbing compounds. The patterns observed by high-resolution time-of-flight aerosol mass spectrometry indicate that oligomers form from repeated imine units. The reactions are 1st order in each reactant: rate-limiting imine formation is followed by rapid dimer and oligomer formation. While excess methylamine evaporates from the droplet, half the glyoxal does not, due to self-oligomerization reactions that occur in the absence of methylamine. Glyoxal irreversibly traps volatile amine compounds in the aerosol phase, converting them into oligomers. This is the first reported mechanism for the formation of stable secondary organic aerosol (SOA) material from methylamine, a substance with only one carbon, and could produce as much as 11 Tg SOA yr−1 globally if glyoxal reacts exclusively by this pathway
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