40,132 research outputs found

    Beauty, elegance, grace, and sexiness compared

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    Beauty is the single most frequently and most broadly used aesthetic virtue term. The present study aimed at providing higher conceptual resolution to the broader notion of beauty by comparing it with three closely related aesthetically evaluative concepts which are likewise lexicalized across many languages: elegance, grace(fulness), and sexiness. We administered a variety of questionnaires that targeted perceptual qualia, cognitive and affective evaluations, as well as specific object properties that are associated with beauty, elegance, grace, and sexiness in personal looks, movements, objects of design, and other domains. This allowed us to reveal distinct and highly nuanced profiles of how a beautiful, elegant, graceful, and sexy appearance is subjectively perceived. As aesthetics is all about nuances, the fine-grained conceptual analysis of the four target concepts of our study provides crucial distinctions for future research

    On the inducibility of small trees

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    The quantity that captures the asymptotic value of the maximum number of appearances of a given topological tree (a rooted tree with no vertices of outdegree 11) SS with kk leaves in an arbitrary tree with sufficiently large number of leaves is called the inducibility of SS. Its precise value is known only for some specific families of trees, most of them exhibiting a symmetrical configuration. In an attempt to answer a recent question posed by Czabarka, Sz\'ekely, and the second author of this article, we provide bounds for the inducibility J(A5)J(A_5) of the 55-leaf binary tree A5A_5 whose branches are a single leaf and the complete binary tree of height 22. It was indicated before that J(A5)J(A_5) appears to be `close' to 1/41/4. We can make this precise by showing that 0.24707J(A5)0.247450.24707\ldots \leq J(A_5) \leq 0.24745\ldots. Furthermore, we also consider the problem of determining the inducibility of the tree Q4Q_4, which is the only tree among 44-leaf topological trees for which the inducibility is unknown

    150°C amorphous silicon thin-film transistor technology for polyimide substrates

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    We have developed a 150°C technology for amorphous silicon thin-film transistors (a-Si:H TFTs) on polyimide substrates deposited by plasma enhanced chemical vapor deposition. The silicon nitride gate dielectric and the a-Si:H channel material were tailored to provide the least leakage current and midgap defect density, respectively. In addition, we conducted experiments on the TFT structure and fabrication with the aim of obtaining high electron mobility. TFTs with back-channel etch and channel-passivated structures were fabricated on glass or 51 μm thick polyimide foil. The a-Si:H TFTs have an on/off current ratio of ∼10 7 and an electron mobility of ∼0.7 cm 2/V s

    Energy and Economic Trade Offs for Advanced Technology Subsonic Aircraft

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    Changes in future aircraft technology which conserve energy are studied, along with the effect of these changes on economic performance. Among the new technologies considered are laminar-flow control, composite materials with and without laminar-flow control, and advanced airfoils. Aircraft design features studied include high-aspect-ratio wings, thickness ratio, and range. Engine technology is held constant at the JT9D level. It is concluded that wing aspect ratios of future aircraft are likely to significantly increase as a result of new technology and the push of higher fuel prices. Composite materials may raise aspect radio to about 11 to 12 and practical laminar flow-control systems may further increase aspect ratio to 14 or more. Advanced technology provides significant reductions in aircraft take-off gross weight, energy consumption, and direct operating cost

    Improved estimators for dispersion models with dispersion covariates

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    In this paper we discuss improved estimators for the regression and the dispersion parameters in an extended class of dispersion models (J{\o}rgensen, 1996). This class extends the regular dispersion models by letting the dispersion parameter vary throughout the observations, and contains the dispersion models as particular case. General formulae for the second-order bias are obtained explicitly in dispersion models with dispersion covariates, which generalize previous results by Botter and Cordeiro (1998), Cordeiro and McCullagh (1991), Cordeiro and Vasconcellos (1999), and Paula (1992). The practical use of the formulae is that we can derive closed-form expressions for the second-order biases of the maximum likelihood estimators of the regression and dispersion parameters when the information matrix has a closed-form. Various expressions for the second-order biases are given for special models. The formulae have advantages for numerical purposes because they require only a supplementary weighted linear regression. We also compare these bias-corrected estimators with two different estimators which are also bias-free to the second-order that are based on bootstrap methods. These estimators are compared by simulation

    Energy transfer in finite-size exciton-phonon systems : confinement-enhanced quantum decoherence

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    Based on the operatorial formulation of the perturbation theory, the exciton-phonon problem is revisited for investigating exciton-mediated energy flow in a finite-size lattice. Within this method, the exciton-phonon entanglement is taken into account through a dual dressing mechanism so that exciton and phonons are treated on an equal footing. In a marked contrast with what happens in an infinite lattice, it is shown that the dynamics of the exciton density is governed by several time scales. The density evolves coherently in the short-time limit whereas a relaxation mechanism occurs over intermediated time scales. Consequently, in the long-time limit, the density converges toward a nearly uniform distributed equilibrium distribution. Such a behavior results from quantum decoherence that originates in the fact that the phonons evolve differently depending on the path followed by the exciton to tunnel along the lattice. Although the relaxation rate increases with the temperature and with the coupling, it decreases with the lattice size, suggesting that the decoherence is inherent to the confinement
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