6,639 research outputs found

    Explaining dysfunctional effects of lexicographical communication

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    During a keynote address at an international conference of AFRILEX articles from a bilingual dictionary with Afrikaans as one of the treated languages was presented. One of the articles was that of the lemma vuvuzela, which contained the example sentence Vuvuzelas maak 'n groot lawaai by sokkerwedstryde [± Vuvuzelas make a lot of noise at soccer matches]. A member of the audience criticised this example for apparently not reflecting the notion of festivity and celebration, with which the vuvuzela is also associated; instead, it seemed that the example focused only on a negative feature of the vuvuzela. From the ensuing discussion it became clear that there seemed to be no theoretical framework against which the criticism could be validated and productively dealt with, even though the lexicographer ultimately offered to review the example.This article introduces elements of the theory of lexicographical communication and applies them to scaffold such a framework. It is argued that indicators in dictionary articles can be regarded as lexicographic utterances that carry various types of lexicographic messages. These can be systematically and formally analysed to identify functional, non-functional and dysfunctional effects of lexicographical communication. Problems with lexicographical communication can then be diagnosed and addressed. This potential is illustrated by treating the above-mentioned occurrence as a case study. In conclusion, the value of the relevant elements of the theory for the evaluation of dictionaries is briefly outlined.Keywords: Appeal, dictionary, dysfunctional effect, expressive function, functional effect, information, lexicographer, lexicographic message, lexicographic utterance, lexicographical communication, lexicography, non-functional effect, referential, relational, target userDie verklaring van disfunksionele effekte van leksikografiese kommunikasieGedurende 'n hoofreferaat by 'n internasionale konferensie van AFRILEX is artikels van 'n tweetalige woordeboek met Afrikaans as een van die behandelde tale aangebied. Een van die artikels was dié van die lemma vuvuzela, wat die voorbeeldsin Vuvuzelas maak 'n groot lawaai by sokkerwedstryde bevat het. 'n Lid van die gehoor het hierdie voorbeeld gekritiseer omdat volgens hom dit nie die idee van feestelikheid weerspieël waarmee die vuvuzela ook geassosieer word nie; dit het naamlik gelyk of die voorbeeldsin op slegs 'n negatiewe aspek van die vuvuzela fokus. Uit die voortspruitende bespreking het dit geblyk dat daar nie 'n teoretiese raamwerk bestaan waarvolgens die kritiek bekragtig en produktief hanteer kon word nie, afgesien daarvan dat die leksikograaf aangebied het om die voorbeeldsin te hersien.Hierdie artikel stel elemente van die teorie van leksikografiese kommunikasie bekend en pas hulle toe om so 'n raamwerk te skep. Daar word aangevoer dat aanduiders in woordeboekartikels beskou kan word as leksikografiese uitings wat verskillende tipes leksikografiese boodskappe dra. Hulle kan sistematies en formeel analiseer word om funksionele, niefunksionele en disfunksionele effekte van leksikografiese kommunikasie te identifiseer. Probleme met leksikografiese kommunikasie kan dan gediagnoseer en opgelos word. Hierdie potensiaal word geïllustreer deur die toepassing van die teorie op die bogenoemde voorval as 'n gevallestudie. Ter afsluiting word die relevante elemente van die teorie se waarde in die evaluering van woordeboeke kortliks uiteengesit.Sleutelwoorde: Appèl, difunksionele effek, ekspressief, funksie, funksionele effek, inligting, leksikograaf, leksikografie, leksikografiese boodskap, leksikografiese kommunikasie, leksikografiese uiting, niefunksionele effek, referensieel, relasioneel, tekengebruiker, woordeboe

    Investigations of solutions of Einstein's field equations close to lambda-Taub-NUT

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    We present investigations of a class of solutions of Einstein's field equations close to the family of lambda-Taub-NUT spacetimes. The studies are done using a numerical code introduced by the author elsewhere. One of the main technical complication is due to the S3-topology of the Cauchy surfaces. Complementing these numerical results with heuristic arguments, we are able to yield some first insights into the strong cosmic censorship issue and the conjectures by Belinskii, Khalatnikov, and Lifschitz in this class of spacetimes. In particular, the current investigations suggest that strong cosmic censorship holds in this class. We further identify open issues in our current approach and point to future research projects.Comment: 24 pages, 12 figures, uses psfrag and hyperref; replaced with published version, only minor corrections of typos and reference

    Violations of Lorentz Covariance in Light Front Quark Models

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    Electromagnetic form factors of the nucleon from relativistic quark models are analyzed: results from null-plane projection of the Feynman triangle diagram are compared with a Bakamjian-Thomas model. The magnetic form factors of the models differ by about 15% at spacelike momentum transfer 0.5 GeV^2, while the charge form factors are much closer. Spurious contributions to electromagnetic form factors due to violations of rotational symmetry are eliminated from both models. One method changes magnetic form factors by about 10%, whereas the charge form factors stay nearly the same. Another one changes the charge form factor of the Bakamjian-Thomas model by more than 50%.Comment: 19 pages, 9 figures, Late

    Analysis of Different Types of Regret in Continuous Noisy Optimization

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    The performance measure of an algorithm is a crucial part of its analysis. The performance can be determined by the study on the convergence rate of the algorithm in question. It is necessary to study some (hopefully convergent) sequence that will measure how "good" is the approximated optimum compared to the real optimum. The concept of Regret is widely used in the bandit literature for assessing the performance of an algorithm. The same concept is also used in the framework of optimization algorithms, sometimes under other names or without a specific name. And the numerical evaluation of convergence rate of noisy algorithms often involves approximations of regrets. We discuss here two types of approximations of Simple Regret used in practice for the evaluation of algorithms for noisy optimization. We use specific algorithms of different nature and the noisy sphere function to show the following results. The approximation of Simple Regret, termed here Approximate Simple Regret, used in some optimization testbeds, fails to estimate the Simple Regret convergence rate. We also discuss a recent new approximation of Simple Regret, that we term Robust Simple Regret, and show its advantages and disadvantages.Comment: Genetic and Evolutionary Computation Conference 2016, Jul 2016, Denver, United States. 201

    Willow on yellowstone's northern range: Evidence for a trophic cascade?

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    Reintroduction of wolves (Canis lupus) to Yellowstone National Park in 1995-1996 has been argued to promote a trophic cascade by altering elk (Cervus elaphus) density, habitat-selection patterns, and behavior that, in turn, could lead to changes within the plant communities used by elk. We sampled two species of willow (Salix boothii and S. geyeriana) on the northern winter range to determine whether (1) there was quantitative evidence of increased willow growth following wolf reintroduction, (2) browsing by elk affected willow growth, and (3) any increase in growth observed was greater than that expected by climatic and hydrological factors alone, thereby indicating a trophic cascade caused by wolves. Using stem sectioning techniques to quantify historical growth patterns we found an approximately twofold increase in stem growth-ring area following wolf reintroduction for both species of willow. This increase could not be explained by climate and hydrological factors alone; the presence of wolves on the landscape was a significant predictor of stem growth above and beyond these abiotic factors. Growth-ring area was positively correlated with the previous year's ring area and negatively correlated with the percentage of twigs browsed from the stem during the winter preceding growth, indicating that elk browse impeded stem growth. Our results are consistent with the hypothesis of a behaviorally mediated trophic cascade on Yellowstone's northern winter range following wolf reintroduction. We suggest that the community-altering effects of wolf restoration are an endorsement of ecological-process management in Yellowstone National Park

    Benchmark generator for CEC 2009 competition on dynamic optimization

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    Evolutionary algorithms(EAs) have been widely applied to solve stationary optimization problems. However, many real-world applications are actually dynamic. In order to study the performance of EAs in dynamic environments, one important task is to develop proper dynamic benchmark problems. Over the years, researchers have applied a number of dynamic test problems to compare the performance of EAs in dynamic environments, e.g., the “moving peaks ” benchmark (MPB) proposed by Branke [1], the DF1 generator introduced by Morrison and De Jong [6], the singleand multi-objective dynamic test problem generator by dynamically combining different objective functions of exiting stationary multi-objective benchmark problems suggested by Jin and Sendhoff [2], Yang and Yao’s exclusive-or (XOR) operator [10, 11, 12], Kang’s dynamic traveling salesman problem (DTSP) [3] and dynamic multi knapsack problem (DKP), etc. Though a number of DOP generators exist in the literature, there is no unified approach of constructing dynamic problems across the binary space, real space and combinatorial space so far. This report uses the generalized dynamic benchmark generator (GDBG) proposed in [4], which construct dynamic environments for all the three solution spaces. Especially, in the rea

    Quasilinear hyperbolic Fuchsian systems and AVTD behavior in T2-symmetric vacuum spacetimes

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    We set up the singular initial value problem for quasilinear hyperbolic Fuchsian systems of first order and establish an existence and uniqueness theory for this problem with smooth data and smooth coefficients (and with even lower regularity). We apply this theory in order to show the existence of smooth (generally not analytic) T2-symmetric solutions to the vacuum Einstein equations, which exhibit AVTD (asymptotically velocity term dominated) behavior in the neighborhood of their singularities and are polarized or half-polarized.Comment: 78 page

    Comparative studies of the scanning tunneling spectra in cuprate and iron-arsenide superconductors

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    We report scanning tunneling spectroscopic studies of cuprate and iron-arsenic superconductors, including YBa_2Cu_3O_{7-\delta} (Y-123, T_c = 93 K), Sr_{0.9}La_{0.1}CuO_2 (La-112, T_c = 43 K), and the "122" compounds Ba(Fe_{1-x}Co_x)_2As_2 (Co-122 with x = 0.06, 0.08, 0.12 for T_c = 14, 24, 20 K). For H > 0, pseudogap (\Delta_{PG}) features are revealed inside the vortices, with \Delta_{PG} = [(\Delta_{eff})^2+(\Delta_{SC})^2]^{1/2} > \Delta_{SC} in Y-123 and \Delta_{PG} < \Delta_{SC} in La-112, suggesting that the physical origin of \Delta_{PG} is a competing order coexisting with superconductivity. Additionally, Fourier transformation (FT) of the Y-123 spectra exhibits two types of spectral peaks, one type is associated with energy (\omega)-dependent quasiparticle interference (QPI) wave-vectors and the other consists of \omega-independent wave-vectors due to competing orders and (\pi,\pi) magnetic resonances. For the multi-band Co-122 compounds, two-gap superconductivity is found for all doping levels. Magnetic resonant modes that follow the temperature dependence of the superconducting gaps are also identified. These findings, together with the \omega- and x-dependent QPI spectra, are consistent with a sign-changing s-wave pairing symmetry in the Co-122 iron arsenides. Our comparative studies suggest that the commonalities among the cuprate and the ferrous superconductors include the proximity to competing orders, antiferromagnetic (AFM) spin fluctuations and magnetic resonances in the superconducting (SC) state, and the unconventional pairing symmetries with sign-changing order parameters on different parts of the Fermi surface.Comment: 6 pages, 3 figures. Submitted to Journal of Physics: Conference Proceedings for the 26th International Low-Temperature Conference (2011). Corresponding author: Nai-Chang Yeh ([email protected]

    The Role of Diffusion in ISOL Targets for the Production of radioactive Ions Beams

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    On line isotope separation techniques (ISOL) for production of ion beams of short-lived radionuclides require fast separation of nuclear reaction products from irradiated target materials followed by a transfer into an ion source. As a first step in this transport chain the release of nuclear reaction products from refractory metals has been studied systematically and will be reviewed. High-energy protons (500-1000MeV) produce a large number of radionuclides in irradiated materials via the nuclear reactions spallation, fission and fragmentation. Foils and powder of Re, W, Ta, Hf, Mo, Nb, Zr, Y, Ti and C were irradiated with protons (600-1000MeV) at the Dubna synchrocyclotron and at the CERN PS-booster to produce different nuclear reaction products. The main topic of the paper is the determination of diffusion coefficients of the nuclear reaction products in the target matrix, data evaluation and a systematic interpretation of the data. The influence of the ionic radius of the diffusing species and the lattice type of the host material used as matrix or target on the diffusion will be evaluated from these systematics. Special attention was directed to the release of group I, II and III-elements. Arrhenius plots lead to activation energies of the diffusion process

    In-medium nucleon-nucleon potentials in configuration space

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    Based on the thermodynamic Green function approach two-nucleon correlations in nuclear matter at finite temperatures are revisited. To this end, we derive phase equivalent effective rr-space potentials that include the effect of the Pauli blocking at a given temperature and density. These potentials enter into a Schr\"odinger equation that is the rr-space representation of the Galitskii-Feynman equation for two nucleons. We explore the analytical structure of the equation in the complex kk-plane by means of Jost functions. We find that despite the Mott effect the correlation with deuteron quantum numbers are manifested as antibound states, i.e., as zeros of the Jost function on the negative imaginary axis of the complex momentum space. The analysis presented here is also suited for Coulombic systems.Comment: 6 pages, 1 table, 4 figure
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