22,443 research outputs found

    Process transparency on construction sites : examples from construction companies in Brazil

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    Process transparency is the core concept in Visual Management (VM), which is one of the founding blocks of the Toyota Production System. This paper presents the preliminary results of a collaborative research conducted between Brazil and the UK, as part of a research effort focused on the application of Visual Management in construction. How process transparency is realized on construction sites is the main research question of the paper. The use of this concept and the implementation of the transparency theory were investigated through multiple case studies, carried out in nine different construction companies. The findings are explained through six theoretical transparency increasing approaches. The affecting parameters in the application of, the management’s perception of and several methods in process transparency in construction were identified. Further work, especially exploring the functions of process transparency on construction sites and reflecting the worker perception of the issue, is necessary to elaborate the process transparency concept

    New Understanding of Large Magellanic Cloud Structure, Dynamics and Orbit from Carbon Star Kinematics

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    We derive general expressions for the LMC velocity field which we fit to kinematical data for 1041 carbon stars. We demonstrate that all previous studies of LMC kinematics have made unnecessary over-simplifications that have led to incorrect estimates of important structural parameters. We compile and improve LMC proper motion estimates to support our analysis. We find that the kinematically determined position angle of the line of nodes is 129.9 +/- 6.0 deg. The LMC inclination changes at a rate di/dt = -103 +/- 61 deg/Gyr, a result of precession and nutation induced by Milky Way tidal torques. The LMC rotation curve V(R) has amplitude 49.8 +/- 15.9 km/s, 40% lower than what has previously (and incorrectly) been inferred from e.g. HI. The dynamical center of the carbon stars is consistent with the center of the bar and the center of the outer isophotes, but not with the HI kinematical center. The enclosed mass inside 8.9 kpc is (8.7 +/- 4.3) x 10^9 M_sun, more than half of which is due to a dark halo. The LMC has a larger vertical thickness than has traditionally been believed. Its V/sigma is less than the value for the Milky Way thick disk. We discuss the implications for the LMC self-lensing optical depth. We determine the LMC velocity and orbit in the Galactocentric rest frame and find it to be consistent with the range of velocities that has been predicted by models for the Magellanic Stream. The Milky Way dark halo must have mass >4.3 x 10^{11} M_sun and extent >39 kpc for the LMC to be bound. We predict the LMC proper motion velocity field, and discuss techniques for kinematical distance estimation. [ABRIDGED]Comment: 57 pages, LaTeX, with 11 PostScript figures. Submitted to the Astronomical Journa

    An Optical Approach to the Dynamical Casimir Effect

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    We recently proposed a new approach to analyze the parametric resonance in a vibrating cavity based on the analysis of classical optical paths. This approach is used to examine various models of cavities with moving walls. We prove that our method is useful to extract easily basic physical outcome.Comment: 9 page

    QuestÔes críticas em validação de métodos analíticos.

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    Experimentação e testes de hipĂłteses; Dificuldades em treinamentos; NĂ­vel de validação necessĂĄrio e responsabilidade cabĂ­veis; Dificuldades comuns; Incerteza; Valor verdadeiro; Realização dos experimentos de validação; NĂșmero de repetiçÔes; Faixa de trabalho; Valores aberrantes; Experimentos de precisĂŁo (estudos colaborativos); Amostragem; Incerteza de amostragem; Verificação de conformidade; CrĂ­tica de validação; ConclusĂ”es

    Hunting Galaxies to (and for) Extinction

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    In studies of star-forming regions, near-infrared excess (NIRX) sources--objects with intrinsic colors redder than normal stars--constitute both signal (young stars) and noise (e.g. background galaxies). We hunt down (identify) galaxies using near-infrared observations in the Perseus star-forming region by combining structural information, colors, and number density estimates. Galaxies at moderate redshifts (z = 0.1 - 0.5) have colors similar to young stellar objects (YSOs) at both near- and mid-infrared (e.g. Spitzer) wavelengths, which limits our ability to identify YSOs from colors alone. Structural information from high-quality near-infrared observations allows us to better separate YSOs from galaxies, rejecting 2/5 of the YSO candidates identified from Spitzer observations of our regions and potentially extending the YSO luminosity function below K of 15 magnitudes where galaxy contamination dominates. Once they are identified we use galaxies as valuable extra signal for making extinction maps of molecular clouds. Our new iterative procedure: the Galaxies Near Infrared Color Excess method Revisited (GNICER), uses the mean colors of galaxies as a function of magnitude to include them in extinction maps in an unbiased way. GNICER increases the number of background sources used to probe the structure of a cloud, decreasing the noise and increasing the resolution of extinction maps made far from the galactic plane.Comment: 16 pages and 16 figures. Accepted for publication in ApJ. Full resolution version at http://www.cfa.harvard.edu/COMPLETE/papers/Foster_HuntingGalaxies.pd

    Numerical comparison of two approaches for the study of phase transitions in small systems

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    We compare two recently proposed methods for the characterization of phase transitions in small systems. The validity and usefulness of these approaches are studied for the case of the q=4 and q=5 Potts model, i.e. systems where a thermodynamic limit and exact results exist. Guided by this analysis we discuss then the helix-coil transition in polyalanine, an example of structural transitions in biological molecules.Comment: 16 pages and 7 figure

    Evaluation of influenza vaccination services and users’ perception about its utility: a study in a community pharmacy in Lisbon, Portugal

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    Poster presented at the 25th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID). Copenhagen, Denmark, 25–28 April 201
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