762 research outputs found

    A multi-layered Bayesian network model for structured document retrieval

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    New standards in document representation, like for example SGML, XML, and MPEG-7, compel Information Retrieval to design and implement models and tools to index, retrieve and present documents according to the given document structure. The paper presents the design of an Information Retrieval system for multimedia structured documents, like for example journal articles, e-books, and MPEG-7 videos. The system is based on Bayesian Networks, since this class of mathematical models enable to represent and quantify the relations between the structural components of the document. Some preliminary results on the system implementation are also presented

    Updated limits on visibly and invisibly decaying Higgs bosons from LEP

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    Talk presented at the XXIX Rencontres de Moriond, Electroweak Interactions and Unified Theories, March 12-19, 1994, MeribelTalk presented at the XXIX Rencontres de Moriond, Electroweak Interactions and Unified Theories, March 12-19, 1994, MeribelTalk presented at the XXIX Rencontres de Moriond, Electroweak Interactions and Unified Theories, March 12-19, 1994, Meribe

    Ianus: an Adpative FPGA Computer

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    Dedicated machines designed for specific computational algorithms can outperform conventional computers by several orders of magnitude. In this note we describe {\it Ianus}, a new generation FPGA based machine and its basic features: hardware integration and wide reprogrammability. Our goal is to build a machine that can fully exploit the performance potential of new generation FPGA devices. We also plan a software platform which simplifies its programming, in order to extend its intended range of application to a wide class of interesting and computationally demanding problems. The decision to develop a dedicated processor is a complex one, involving careful assessment of its performance lead, during its expected lifetime, over traditional computers, taking into account their performance increase, as predicted by Moore's law. We discuss this point in detail

    Limits on Associated Production of Visibly and Invisibly Decaying Higgs Bosons from Z Decays

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    Many extensions of the standard electroweak model Higgs sector suggest that the main Higgs decay channel is "invisible", for example, h→JJh \to J J where JJ denotes the majoron, a weakly interacting pseudoscalar Goldstone boson associated to the spontaneous violation of lepton number. In many of these models the Higgs boson may also be produced in association to a massive pseudoscalar boson (HA), in addition to the standard Bjorken mechanism (HZ). We describe a general strategy to determine limits from LEP data on the masses and couplings of such Higgs bosons, using the existing data on acoplanar dijet events as well as data on four and six bb jet event topologies. For the sake of illustration, we present constraints that can be obtained for the ALEPH data.Comment: FTUV/94-36, IFIC/94-31 TIFR/TH/94--25, 12 pages + 4 figures (included as ps files at the end

    Searching for Invisibly Decaying Higgs Bosons at LEP II

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    We study the potential of LEP II to unravel the existence of invisibly decaying Higgs bosons, predicted in a wide class of models. We perform a model independent analysis, focusing our attention to the final state topologies exhibiting bbˉb \bar{b} or ℓ+ℓ−\ell^+ \ell^- (ℓ=ÎŒ\ell=\mu or ee) pairs and missing energy. We carefully evaluate the signals and backgrounds, choosing appropriate cuts to enhance the discovery limits. Our results demonstrate that LEP II is capable of discovering such a Higgs boson for a wide range of masses and couplings.Comment: 22 pages, latex, uses epsfig.sty, 5 figure

    Spontaneous R-Parity violation bounds

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    We investigate bounds from tree-level and one-loop processes in generic supersymmetric models with spontaneous R-parity breaking in the superpotential. We analyse the bounds from a general point of view. The bounds are applicable both for all models with spontaneous R-parity violation and for explicit bilinear R-parity violation based on general lepton-chargino and neutrino-neutralino mixings. We find constraints from semileptonic B, D and K decays, leptonic decays of the mu and tau, electric dipole moments, as well as bounds for the anomalous magnetic moment of the muon.Comment: 22 page

    Review: potential biotechnological assets related to plant immunity modulation applicable in engineering disease-resistant crops.

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    Made available in DSpace on 2018-05-26T00:37:56Z (GMT). No. of bitstreams: 1 1s2.0S0168945217309421main.pdf: 689707 bytes, checksum: 038b121ee1da5c77d7ee341664f7e460 (MD5) Previous issue date: 2018-05-25bitstream/item/177697/1/1-s2.0-S0168945217309421-main.pd

    Model Independent Higgs Boson Mass Limits at LEP

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    We derive model-independent constraints on Higgs mass and couplings from associated signals for higher masses, accessible at LEP2. This work is motivated by the fact that, in many extensions of the standard model, the Higgs boson can have substantial "invisible" decay modes, for example, into light or massless weakly interacting Goldstone bosons associated to the spontaneous violation of lepton number below the weak scale.Comment: FTUV/93-19, 13 pag + 2 figures(not included but available upon request), Late

    The tomato mutant ars1 (altered response to salt stress 1) identifies an R1-type MYB transcription factor involved in stomatal closure under salt acclimation

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    [EN] A screening under salt stress conditions of a T-DNA mutant collection of tomato (Solanum lycopersicum L.) led to the identification of the altered response to salt stress 1 (ars1) mutant, which showed a salt-sensitive phenotype. Genetic analysis of the ars1 mutation revealed that a single T-DNA insertion in the ARS1 gene was responsible of the mutant phenotype. ARS1 coded for an R1-MYB type transcription factor and its expression was induced by salinity in leaves. The mutant reduced fruit yield under salt acclimation while in the absence of stress the disruption of ARS1 did not affect this agronomic trait. The stomatal behaviour of ars1 mutant leaves induced higher Na+ accumulation via the transpiration stream, as the decreases of stomatal conductance and transpiration rate induced by salt stress were markedly lower in the mutant plants. Moreover, the mutation affected stomatal closure in a response mediated by abscisic acid (ABA). The characterization of tomato transgenic lines silencing and overexpressing ARS1 corroborates the role of the gene in regulating the water loss via transpiration under salinity. Together, our results show that ARS1 tomato gene contributes to reduce transpirational water loss under salt stress. Finally, this gene could be interesting for tomato molecular breeding, because its manipulation could lead to improved stress tolerance without yield penalty under optimal culture conditions.This work was funded by a research project (AGL2012-40150-C01/C02/C03) from the Spanish Ministry of Economy and Competitiveness (MINECO). This work was also supported by grant RYC2010-06369 (Ramon y Cajal Programme) from the MINECO to NF-G and grant E-30-2011-0443170 (JAE-Doc Programme) from the Spanish Council of Scientific Research (CSIC) to IE and BP. The authors have no conflict of interests to declareCampos, JF.; Cara, B.; Perez-Martin, F.; Pineda Chaza, BJ.; Egea, I.; Flores, FB.; Fernandez-Garcia, N.... (2016). The tomato mutant ars1 (altered response to salt stress 1) identifies an R1-type MYB transcription factor involved in stomatal closure under salt acclimation. Plant Biotechnology Journal. 14(6):1345-1356. https://doi.org/10.1111/pbi.124981345135614
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