1,662 research outputs found

    Determinación del eje de la carretera y la distancia de visibilidad utilizando datos GPS y herramientas SIG

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    Hoy en día, tanto en el proceso de diseño de las carreteras como en el análisis del funcionamiento de las ya construidas, se está dando cada vez más importancia a la seguridad vial. Entre los distintos aspectos que se consideran se encuentra la distancia de visibilidad. Por otra parte, uno de los problemas que aparecen en la práctica al tratar de analizar carreteras en servicio es la falta de datos de la geometría del eje que estén actualizados y tengan la precisión requerida. En esta comunicación se presenta un procedimiento para determinar el eje de la carretera mediante información GPS y calcular la distancia de visibilidad aplicando herramientas SIG. El procedimiento se ha aplicado a un tramo de carretera convencional de doble sentido de circulación. El método propuesto puede ser especialmente útil en aquellas carreteras en servicio y de las que, por no contar con la información sobre su trazado (original o posteriores modificaciones), no es posible utilizar los programas de diseño de carreteras para el cálculo de la distancia de visibilidad.Nowadays road safety aspects are very important, both for the designing process and for the analysis of already built roads. Sight distance is one of the most important road safety aspects to consider. On the other hand, the geometric definition of already built roads is one of the most difficult issues that arise in practice. This road geometry must be accurate and up to date. In this paper, a procedure to determine the alignment of a road using a GPS and to calculate sight distances using GIS tools is presented. Also, the use of this procedure in a two-lane rural road is described. The proposed method can be especially useful for those roads whose design data are not available because, on them, road design software could not be used for sight distance calculation

    The trimer interface in the quaternary structure of the bifunctional prokaryotic FAD synthetase from Corynebacterium ammoniagenes

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    Bifunctional FAD synthetases (FADSs) fold in two independent modules; The C-terminal riboflavin kinase (RFK) catalyzes the RFK activity, while the N-terminal FMN-adenylyltransferase (FMNAT) exhibits the FMNAT activity. The search for macromolecular interfaces in the Corynebacterium ammoniagenes FADS (CaFADS) crystal structure predicts a dimer of trimers organization. Within each trimer, a head-to-tail arrangement causes the RFK and FMNAT catalytic sites of the two neighboring protomers to approach, in agreement with active site residues of one module influencing the activity at the other. We analyze the relevance of the CaFADS head-to-tail macromolecular interfaces to stabilization of assemblies, catalysis and ligand binding. With this aim, we evaluate the effect of point mutations in loop L1c-FlapI, loop L6c, and helix a1c of the RFK module (positions K202, E203, F206, D298, V300, E301 and L304), regions at the macromolecular interface between two protomers within the trimer. Although none of the studied residues is critical in the formation and dissociation of assemblies, residues at L1c-FlapI and helix a1c particularly modulate quaternary architecture, as well as ligand binding and kinetic parameters involved with RFK and FMNAT activities. These data support the influence of transient oligomeric structures on substrate accommodation and catalysis at both CaFADS active sites

    A Classification of Integrable Quasiclassical Deformations of Algebraic Curves

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    A previously introduced scheme for describing integrable deformations of of algebraic curves is completed. Lenard relations are used to characterize and classify these deformations in terms of hydrodynamic type systems. A general solution of the compatibility conditions for consistent deformations is given and expressions for the solutions of the corresponding Lenard relations are provided.Comment: 21 page

    On the Whitham hierarchy: dressing scheme, string equations and additional symmetrie

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    A new description of the universal Whitham hierarchy in terms of a factorization problem in the Lie group of canonical transformations is provided. This scheme allows us to give a natural description of dressing transformations, string equations and additional symmetries for the Whitham hierarchy. We show how to dress any given solution and prove that any solution of the hierarchy may be undressed, and therefore comes from a factorization of a canonical transformation. A particulary important function, related to the τ\tau-function, appears as a potential of the hierarchy. We introduce a class of string equations which extends and contains previous classes of string equations considered by Krichever and by Takasaki and Takebe. The scheme is also applied for an convenient derivation of additional symmetries. Moreover, new functional symmetries of the Zakharov extension of the Benney gas equations are given and the action of additional symmetries over the potential in terms of linear PDEs is characterized

    Integrable Quasiclassical Deformations of Cubic Curves

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    A general scheme for determining and studying hydrodynamic type systems describing integrable deformations of algebraic curves is applied to cubic curves. Lagrange resolvents of the theory of cubic equations are used to derive and characterize these deformations.Comment: 24 page

    On the Whitham hierarchy: dressing scheme, string equations and additional symmetrie

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    A new description of the universal Whitham hierarchy in terms of a factorization problem in the Lie group of canonical transformations is provided. This scheme allows us to give a natural description of dressing transformations, string equations and additional symmetries for the Whitham hierarchy. We show how to dress any given solution and prove that any solution of the hierarchy may be undressed, and therefore comes from a factorization of a canonical transformation. A particulary important function, related to the τ\tau-function, appears as a potential of the hierarchy. We introduce a class of string equations which extends and contains previous classes of string equations considered by Krichever and by Takasaki and Takebe. The scheme is also applied for an convenient derivation of additional symmetries. Moreover, new functional symmetries of the Zakharov extension of the Benney gas equations are given and the action of additional symmetries over the potential in terms of linear PDEs is characterized

    The High Cadence Transit Survey (HiTS): Compilation and Characterization of Light-curve Catalogs

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    Indexación: Scopus.J.M. acknowledges support from CONICYT-Chile through CONICYT-PCHA/Doctorado-Nacional/2014-21140892. J.M., F.F., G.C.V., and G.M. acknowledge support from the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to the Millennium Institute of Astrophysics (MAS). F.F. acknowledges support from Conicyt through the Fondecyt Initiation into Research project No. 11130228. J.M., F.F., J.S.M., G.C.V., and S.G. acknowledge support from Basal Project PFB-03, Centro de Modelamiento Matemáico (CMM), Universidad de Chile. P.L. acknowledges support by Fondecyt through project #1161184. G.C.V. gratefully acknowledges financial support from CON-ICYT-Chile through FONDECYT postdoctoral grant number 3160747 and CONICYT-Chile and NSF through the Programme of International Cooperation project DPI201400090. P.H. acknowledges support from FONDECYT through grant 1170305. L.G. was supported in part by the US National Science Foundation under grant AST-1311862. G.M. acknowledges support from Conicyt through CONICYT-PCHA/Magís-terNacional/2016-22162353. Support for T.d.J. has been provided by US NSF grant AST-1211916, the TABASGO Foundation, and Gary and Cynthia Bengier. R.R.M. acknowledges partial support from BASAL Project PFB-06, as well as FONDECYT project N◦1170364. Powered@NLHPC: this research was supported by the High Performance Computing infrastructure of the National Laboratory for High Performance Computing (NLHPC), PIA ECM-02, CONICYT. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaborating institutions: Argonne National Lab, the University of California Santa Cruz, the University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologi-cas-Madrid, the University of Chicago, University College London, the DES-Brazil consortium, the University of Edinburgh, ETH-Zurich, the University of Illinois at Urbana-Champaign, Institut de Ciencies de l’Espai, Institut de Fisica d’Altes Energies, Lawrence Berkeley National Lab, Ludwig-Maximilians Universitat, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Lab, Stanford University, the University of Sussex, and Texas A&M University. Funding for DES, including DECam, has been provided by the U.S. Department of Energy, National Science Foundation, Ministry of Education and Science (Spain), Science and Technology Facilities Council (UK), Higher Education Funding Council (England), National Center for Supercomputing Applications, Kavli Institute for Cosmological Physics, Financia-dora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo a Pesquisa, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência e Tecnologia (Brazil), the German Research Foundation-sponsored cluster of excellence “Origin and Structure of the universe,” and the DES collaborating institutions. Facility: CTIO:1.5 m (DECam).The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ∼15 million object detections and a catalog of ∼2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one δ Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate. The first data release can be accessed in the project archive of HiTS (http://astro.cmm.uchile.cl/HiTS/). © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-3881/aadfd

    Semiclassical expansions in the Toda hierarchy and the hermitian matrix model

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    An iterative algorithm for determining a class of solutions of the dispersionful 2-Toda hierarchy characterized by string equations is developed. This class includes the solution which underlies the large N-limit of the Hermitian matrix model in the one-cut case. It is also shown how the double scaling limit can be naturally formulated in this schemeComment: 22 page

    Has cupper ion any effect on Sinorhizobium Melitoili bacteria?

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    Proceedings of the I Congress PIIISA celebrado en la Estación Experimental del Zaidín, Granada, el 26 de abril de 2012.Sinorhizobium meliloti is a soil bacterium that in symbiosis with Alfalfa leguminous plants fixes N2 to ammonia. This process occurs after an intimate communication between host and microsimbiont in the rhizosphere niche. This soil bacterium may suffer biotic and abiotic stresses in this complex environment. Resistance to any of this stresses can be an advantage for this type of bacteria. In this work we test the effects of Cupper ion in the bacterium Sinorhizobium meliloti. We found an effect on pigmentation and this effect is specific of each isolate (i.e. it is very pronounced for the isolate AK83 from Aral sea in Russia). On the other hand, comparison of Cupper ion resistance phenotype between isolates 1021 and GR4 suggests that the resistance of GR4 could be due to a set of 10 genes found in the cryptic plasmid pRmeGR4a of this strain. However, this resistance phenotype also appears in other isolates, and it could be explained by an alternative phenotype as Exopolysaccaride production (EPS+).It was supported mainly by research project MICINN Consolider‐Ingenio 2010. CSD2009‐00006; Scientific research by Young Students in Science (PIIISA2012; http://emc2astronomy.blogspot.com/).Peer reviewe

    Identification of inhibitors targeting ferredoxin-NADP+ reductase from the xanthomonas citri subsp. Citri phytopathogenic bacteria

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    Ferredoxin-NADP(H) reductases (FNRs) deliver NADPH or low potential one-electron donors to redox-based metabolism in plastids and bacteria. Xanthomonas citri subsp. citri (Xcc) is a Gram-negative bacterium responsible for citrus canker disease that affects commercial citrus crops worldwide. The Xcc fpr gene encodes a bacterial type FNR (XccFPR) that contributes to the bacterial response to oxidative stress conditions, usually found during plant colonization. Therefore, XccFPR is relevant for the pathogen survival and its inhibition might represent a strategy to treat citrus canker. Because of mechanistic and structural differences from plastidic FNRs, XccFPR is also a potential antibacterial target. We have optimized an activity-based high-throughput screening (HTS) assay that identifies XccFPR inhibitors. We selected 43 hits from a chemical library and narrowed them down to the four most promising inhibitors. The antimicrobial effect of these compounds was evaluated on Xcc cultures, finding one with antimicrobial properties. Based on the functional groups of this compound and their geometric arrangement, we identified another three XccFPR inhibitors. Inhibition mechanisms and constants were determined for these four XccFPR inhibitors. Their specificity was also evaluated by studying their effect on the plastidic Anabaena PCC 7119 FNR, finding differences that can become interesting tools to discover Xcc antimicrobials
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