1,011 research outputs found

    Lessons learned from 14 years of the GEOIDE network

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    Over fourteen years, the GEOIDE Network has set a standard for excellence in delivering results of research to user communities across disciplinary boundaries

    A deflationary approach to fundamental principles in GIScience

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    While the practice of mapping has ancient, even prehistoric, roots, the past fifty years have seen increased emphasis on the sciences of geographic information. A key element is moving from the fixation with the specific constraints of the mapped product (the graphic artifact) to re-centering attention on databases as the resources for constructing all potential maps, and the GIS as the basis for all models of process of change. There is an early indication of this approach enunciated in a short (threepage) article by John Sherman and Waldo Tobler in Professional Geographer (Sherman and Tobler 1957; Chrisman 1997a). This was followed by a work on the promise of digital technology (Tobler 1959). Perhaps one of the clearest articulations in the rethinking of cartography was Board's (1967) "Maps as Models"

    Wax Chemical and Morphological Investigation of Brazilian Crude Oils

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    The waxes in petroleum can precipitate and form unwanted gels and deposition when exposed to low temperatures. The idea of this chapter is to approach methods of quantification and physicochemical and morphological characterization of waxes and how this information can help in understanding this deposition. Information such as the quantity of waxes and the chemical structures in the oil is fundamental to predict the possible deposition and its ability to aggregate with other crystals. For example, the knowledge about the wax morphology may contribute to explain the nucleation and growth of the deposits. The polarized light microscopy, the most common technique to visualize wax crystals, and the bright-field microscopy, the most simple technique, able to show crystal details that have not been seen on the polarized light, was used

    Normative Alethic Pluralism

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    Some philosophers have argued that truth is a norm of judgement and have provided a variety of formulations of this general thesis. In this paper, I shall side with these philosophers and assume that truth is a norm of judgement. What I am primarily interested in here are two core questions concerning the judgement-truth norm: (i) what are the normative relationships between truth and judgement? And (ii) do these relationships vary or are they constant? I argue for a pluralist picture—what I call Normative Alethic Pluralism (NAP)—according to which (i) there is more than one correct judgement-truth norm and (ii) the normative relationships between truth and judgement vary in relation to the subject matter of the judgement. By means of a comparative analysis of disagreement in three areas of the evaluative domain—refined aesthetics, basic taste and morality—I show that there is an important variability in the normative significance of disagreement—I call this the variability conjecture. By presenting a variation of Lynch’s scope problem for alethic monism, I argue that a monistic approach to the normative function of truth is unable to vindicate the conjecture. I then argue that normative alethic pluralism provides us with a promising model to account for it

    Measurements of Flavour Dependent Fragmentation Functions in Z^0 -> qq(bar) Events

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    Fragmentation functions for charged particles in Z -> qq(bar) events have been measured for bottom (b), charm (c) and light (uds) quarks as well as for all flavours together. The results are based on data recorded between 1990 and 1995 using the OPAL detector at LEP. Event samples with different flavour compositions were formed using reconstructed D* mesons and secondary vertices. The \xi_p = ln(1/x_E) distributions and the position of their maxima \xi_max are also presented separately for uds, c and b quark events. The fragmentation function for b quarks is significantly softer than for uds quarks.Comment: 29 pages, LaTeX, 5 eps figures (and colour figs) included, submitted to Eur. Phys. J.

    Search for Neutral Higgs Bosons in e+e- Collisions at sqrt(s) ~189GeV

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    A search for neutral Higgs bosons has been performed with the OPAL detector at LEP, using approximately 170 pb-1 of e+e- collision data collected at sqrt(s)~189GeV. Searches have been performed for the Standard Model (SM) process e+e- to H0Z0 and the MSSM processes e+e- to H0Z0, A0h0. The searches are sensitive to the b b-bar and tau antitau decay modes of the Higgs bosons, and also to the MSSM decay mode h0 to A0A0. OPAL search results at lower centre-of-mass energies have been incorporated in the limits we set, which are valid at the 95% confidence level. For the SM Higgs boson, we obtain a lower mass bound of 91.0 GeV. In the MSSM, our limits are mh>74.8GeV and mA>76.5GeV, assuming tan(beta)>1, that the mixing of the scalar top quarks is either zero or maximal, and that the soft SUSY-breaking masses are 1 TeV. For the case of zero scalar top mixing, we exclude values of tan(beta) between 0.72 and 2.19.Comment: 38 pages, 15 figures, submitted Euro. Phys. J.

    Bose-Einstein Correlations in e+e- to W+W- at 172 and 183 GeV

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    Bose-Einstein correlations between like-charge pions are studied in hadronic final states produced by e+e- annihilations at center-of-mass energies of 172 and 183 GeV. Three event samples are studied, each dominated by one of the processes W+W- to qqlnu, W+W- to qqqq, or (Z/g)* to qq. After demonstrating the existence of Bose-Einstein correlations in W decays, an attempt is made to determine Bose-Einstein correlations for pions originating from the same W boson and from different W bosons, as well as for pions from (Z/g)* to qq events. The following results are obtained for the individual chaoticity parameters lambda assuming a common source radius R: lambda_same = 0.63 +- 0.19 +- 0.14, lambda_diff = 0.22 +- 0.53 +- 0.14, lambda_Z = 0.47 +- 0.11 +- 0.08, R = 0.92 +- 0.09 +- 0.09. In each case, the first error is statistical and the second is systematic. At the current level of statistical precision it is not established whether Bose-Einstein correlations, between pions from different W bosons exist or not.Comment: 24 pages, LaTeX, including 6 eps figures, submitted to European Physical Journal
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