57,073 research outputs found

    Solving congestion (when we must not build roads, increase spending, lose votes, damage the economy or harm the environment, and will never find equilibrium)

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    An account of the development of transport and traffic policy over the last 30 years, with suggestions for the future constraints and objective

    Science and Technology Development and Promotion in the Private Sector: Some Issues and Recommendations for Policy Research

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    This article is part of the seminar on “Science Technology Policies in the Philippines" jointly sponsored by PIDS and DOST on May 5, 1989. It emphasizes the need for scientific research specifically the need for dissemination and utilization of information technology.science and technology, information technology (IT), technological innovation

    Science and Technology Development and Promotion in the Private Sector: Some Issues and Recommendations for Policy Research

    Get PDF
    This article is part of the seminar on “Science Technology Policies in the Philippines" jointly sponsored by PIDS and DOST on May 5, 1989. It emphasizes the need for scientific research specifically the need for dissemination and utilization of information technology.science and technology, information technology (IT), technological innovation

    Surface modification of hydrophobic polymers for improvement of endothelial cell-surface interactions

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    The aim of this study is to improve the interaction of endothelial cells with polymers used in vascular prostheses. Polytetrafluoroethylene (PTFE; Teflon) films were treated by means of nitrogen and oxygen plasmas. Depending on the plasma exposure time, modified PTFE surfaces showed water-contact angles of 15¿58° versus 96° for unmodified PTFE. Electron spectroscopy in chemical analysis (ESCA) measurements revealed incorporation of both nitrogenand oxygen-containing groups into the PTFE surfaces, dependent on the plasma composition and exposure time. In-vitro biological evaluation of unmodified and modified PTFE surfaces showed that human endothelial cells, seeded from 20% human serum-containing culture medium, adhered well on to modified PTFE surfaces, but not on to unmodified films. Adhesion of endothelial cells on to expanded PTFE graft material (Gore-Tex) was also stimulated by plasma treatment of this substrate. On plasma-treated expanded PTFE, the adhering endothelial cells formed a monolayer, which covered the textured surface. The latter observation is important in view of the hemocompatibility of vascular grafts seeded with endothelial cells before implantation

    Quantifying Bar Strength: Morphology Meets Methodology

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    A set of objective bar-classification methods have been applied to the Ohio State Bright Spiral Galaxy Survey (Eskridge et al. 2002). Bivariate comparisons between methods show that all methods agree in a statistical sense. Thus the distribution of bar strengths in a sample of galaxies can be robustly determined. There are very substantial outliers in all bivariate comparisons. Examination of the outliers reveals that the scatter in the bivariate comparisons correlates with galaxy morphology. Thus multiple measures of bar strength provide a means of studying the range of physical properties of galaxy bars in an objective statistical sense.Comment: LaTeX with Kluwer style file, 5 pages with 3 embedded figures. edited by Block, D.L., Freeman, K.C., Puerari, I., & Groess,

    Performance of the TSUNAMI (II) macrocellular field trial system using a dynamic interference source

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    Chemical Equilibration in Hadronic Collisions

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    We study chemical equilibration in out-of-equilibrium Quark-Gluon Plasma using the first principles method of QCD effective kinetic theory, accurate at weak coupling. In longitudinally expanding systems--relevant for relativistic nuclear collisions--we find that for realistic couplings chemical equilibration takes place after hydrodynamization, but well before local thermalization. We estimate that hadronic collisions with final state multiplicities dNch/dη102{dN_\text{ch}}/{d\eta}\gtrsim 10^2 live long enough to reach approximate chemical equilibrium, which is consistent with the saturation of strangeness enhancement observed in proton-proton, proton-nucleus and nucleus-nucleus collisions.Comment: 7 pages, 3 figures, see also our companion paper arXiv:1811.03068, v2 small changes, published versio
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