1,112 research outputs found

    Un prototipo computacional para la estimación de costos y planeación de obras con base en modelos BIM

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    La extensión de la funcionalidad de las herramientas que permitan la gestión del modelado de información de edificios (BIM), es una práctica que está tomando auge debido a las limitantes que presentan dichas herramientas en función del contexto donde se han utilizado. En este trabajo se presenta el resultado del desarrollo de un prototipo computacional que permite extender una herramienta que gestiona modelos BIM con el objetivo de proveerla con las funcionalidades de: estimación de costos y programación de obra, utilizando la sincronización entre el modelo BIM y una base de datos con la información complementaria de tiempo y costo. El prototipo permite realizar el estimado de los costos unitarios, el presupuesto de la obra, la cuantificación de la misma mediante la asociación de las instancias de los elementos que conforman el modelo BIM y la programación de la obra con el método de precedencias (PDM). Se concluye que es posible extender las herramientas existentes para la gestión de modelos BIM para adapta las al contexto. Los autores del trabajo consideran importante seguir explorando la utilización de estas herramientas para adaptar otros procesos de diseño-construcción que dependen en forma sustancial del contexto

    The poetics of indigenous radio in Colombia

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    In 2002, 14 indigenous radio stations began operating in Colombia reaching 78.6 percent of the national indigenous population. Colombian indigenous radio stations are shaped by intense deliberations among each indigenous people about the poetics of information and communication technologies, understood as the exploration of the specific sets of social, cultural and political relations in which each radio station would exist if brought into each indigenous territory. Colombian indigenous peoples' appropriation of information and communication technologies is framed by new legislative frameworks made possible by the Colombian constitutional reform of 1991, by indigenous peoples' critique of Colombian mainstream media and, more significantly, by discussions among indigenous peoples about the adoption of radio — what we call a poetics of radio.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Willingness to pay for biofertilizers among grain legume farmers in northern Ghana

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    Open Access Journal; Published online: 27 April 2018Background: The call for use of improved Soil Fertility Management (SFM) technologies is a prerequisite to increase agricultural productivity among farmers. This study assessed farmers’ willingness to pay (WTP) for selected financially rewarding biofertilizer technologies/packages for legume production in northern Ghana. Primary data was elicited from 400 grain legume farmers selected from Northern and Upper West Regions of Ghana through a simple random sampling technique. The double bounded dichotomous choice (DBDC) format of contingent valuation approach was employed to elicit willingness to pay values and determinants of farmers WTP was evaluated using the maximum likelihood estimation procedure. Results: The results showed that about 60%, 25% and 46% of soya, cowpea and groundnuts farmers were willing to pay for the selected biofertilizers (Biofix, BR3267 and Legumefix respectively) at prices not exceeding GHC 14.00, GHC 28.00 and GHC 20.00 per 0.2kg of the respective biofertilizers. Legume farmers in Northern Region were however willing to pay higher for the three biofertilizer technologies as compared to their counterparts in Upper West Region. For 0.2 kg each of Biofix, BR3267 and Legumefix, farmers in Northern Region were willing to pay approximately GHC 17.00, GHC 12.00 and GHC 23.00 respectively whereas those in Upper West Region were willing to pay GHC 14.00, GHC 9.00 and GHC 11.00 for the same quantity of each biofertilizer. The study identified farming experience, FBO membership, awareness and previous use of biofertilizers as significant determinants of farmers’ willingness to pay for Biofertilizers. Conclusion: Comparatively, mean prices farmers are willing to pay for these three technologies are below ex-factory prices, hence subsidizing the cost of production of these biofertilizers in the initial stages would be relevant for improving farmers’ uptake of these fertilizers. Sustained awareness creation through periodic education and sensitization by using FBOs as leverage points is also highly recommended to improve farmers’ understanding of the concept of biofertilizer use

    The Pierre Auger Observatory III: Other Astrophysical Observations

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    Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference, Beijing, China, August 201

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon μ\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, μμ\mu\mu or eμe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction
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