5,526 research outputs found

    A probabilistic interpretation of a sequence related to Narayana polynomials

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    A sequence of coefficients appearing in a recurrence for the Narayana polynomials is generalized. The coefficients are given a probabilistic interpretation in terms of beta distributed random variables. The recurrence established by M. Lasalle is then obtained from a classical convolution identity. Some arithmetical properties of the generalized coefficients are also established

    Tex2Shape: Detailed Full Human Body Geometry From a Single Image

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    We present a simple yet effective method to infer detailed full human body shape from only a single photograph. Our model can infer full-body shape including face, hair, and clothing including wrinkles at interactive frame-rates. Results feature details even on parts that are occluded in the input image. Our main idea is to turn shape regression into an aligned image-to-image translation problem. The input to our method is a partial texture map of the visible region obtained from off-the-shelf methods. From a partial texture, we estimate detailed normal and vector displacement maps, which can be applied to a low-resolution smooth body model to add detail and clothing. Despite being trained purely with synthetic data, our model generalizes well to real-world photographs. Numerous results demonstrate the versatility and robustness of our method

    Learning to Reconstruct People in Clothing from a Single RGB Camera

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    We present a learning-based model to infer the personalized 3D shape of people from a few frames (1-8) of a monocular video in which the person is moving, in less than 10 seconds with a reconstruction accuracy of 5mm. Our model learns to predict the parameters of a statistical body model and instance displacements that add clothing and hair to the shape. The model achieves fast and accurate predictions based on two key design choices. First, by predicting shape in a canonical T-pose space, the network learns to encode the images of the person into pose-invariant latent codes, where the information is fused. Second, based on the observation that feed-forward predictions are fast but do not always align with the input images, we predict using both, bottom-up and top-down streams (one per view) allowing information to flow in both directions. Learning relies only on synthetic 3D data. Once learned, the model can take a variable number of frames as input, and is able to reconstruct shapes even from a single image with an accuracy of 6mm. Results on 3 different datasets demonstrate the efficacy and accuracy of our approach

    Interface dipoles of organic molecules on Ag(111) in hybrid density-functional theory

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    We investigate the molecular acceptors 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA), 2,3,5,6-tetra uoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), and 4,5,9,10-pyrenetetraone (PYTON) on Ag(111) using densityfunctional theory. For two groups of the HSE(\alpha, \omega) family of exchange-correlation functionals (\omega = 0 and \omega = 0.2\AA) we study the isolated components as well as the combined systems as a function of the amount of exact-exchange (\alpha). We find that hybrid functionals favour electron transfer to the adsorbate. Comparing to experimental work-function data, we report for (\alpha) ca. 0.25 a notable but small improvement over (semi)local functionals for the interface dipole. Although Kohn-Sham eigenvalues are only approximate representations of ionization energies, incidentally, at this value also the density of states agrees well with the photoelectron spectra. However, increasing (\alpha) to values for which the energy of the lowest unoccupied molecular orbital matches the experimental electron affinity in the gas phase worsens both the interface dipole and the density of states. Our results imply that semi-local DFT calculations may often be adequate for conjugated organic molecules on metal surfaces and that the much more computationally demanding hybrid functionals yield only small improvements.Comment: submitted to New Journal of Physics (2013). More information can be found at http://th.fhi-berlin.mpg.de/site/index.php?n=Publications.Publication

    The Moments of the Hydrogen Atom by the Method of Brackets

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    Expectation values of powers of the radial coordinate in arbitrary hydrogen states are given, in the quantum case, by an integral involving the associated Laguerre function. The method of brackets is used to evaluate the integral in closed-form and to produce an expression for this average value as a finite sum

    Derivation of an integral of Boros and Moll via convolution of Student t-densities

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    We show that the evaluation of an integral considered by Boros and Moll is a special case of a convolution result about Student t-densities obtained by the authors in 2008

    The Cauchy-Schlomilch transformation

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    The Cauchy-Schl\"omilch transformation states that for a function ff and a,b>0a, \, b > 0, the integral of f(x2)f(x^{2}) and af((axbx1)2af((ax-bx^{-1})^{2} over the interval [0,)[0, \infty) are the same. This elementary result is used to evaluate many non-elementary definite integrals, most of which cannot be obtained by symbolic packages. Applications to probability distributions is also given

    Enacted support and golf-putting performance: The role of support type and support visibility

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    Objectives This study examined whether the impact of enacted support on performance differed across type (esteem and informational) and visibility (visible and invisible) of support. It further tested whether self-efficacy mediated the enacted support-performance relationship. Design A one-factor (support manipulation) between subjects experiment. Method A fellow novice golfer — in reality a confederate — was scripted to randomly provide one of five support manipulations (visible informational support, invisible informational support, visible esteem support, invisible esteem support, and no support) to participants (n = 105). Immediately after, participants completed a self-efficacy measure and then performed a golf-putting task. Results The results demonstrated that participants given visible esteem support significantly outperformed those given no support and those given invisible esteem support. Participants given invisible informational support significantly outperformed those given no support. Although non-significant, the observed mean difference and moderate effect size provided weak evidence that those in the invisible informational support condition may have performed at a higher level than those in the visible informational support condition. There was no evidence that self-efficacy could explain any of these effects. Conclusion The results suggest that enacted support can benefit novices’ performance and that it is crucial to consider both the type and the visibility of the support. Esteem support is particularly effective when communicated in an explicit and direct manner but informational support appears more effective when communicated in a more subtle, indirect manner

    Disrupted glycosylation of lipids and proteins is a cause of neurodegeneration

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    Glycosyltransferases represent a large family of enzymes that catalyse the biosynthesis of oligosaccharides, polysaccharides, and glycoconjugates. A number of studies have implicated glycosyltransferases in the pathogenesis of neurodegenerative diseases but differentiating cause from effect has been difficult. We have recently discovered that mutations proximal to the substrate binding site of glycosyltransferase 8 domain containing 1 (GLT8D1) are associated with familial amyotrophic lateral sclerosis (ALS). We demonstrated that ALS-associated mutations reduce activity of the enzyme suggesting a loss-of-function mechanism that is an attractive therapeutic target. Our work is the first evidence that isolated dysfunction of a glycosyltransferase is sufficient to cause a neurodegenerative disease, but connection between neurodegeneration and genetic variation within glycosyltransferases is not new. Previous studies have identified associations between mutations in UGT8 and sporadic ALS, and between ST6GAL1 mutations and conversion of mild cognitive impairment into clinical Alzheimer’s disease. In this review we consider potential mechanisms connecting glycosyltransferase dysfunction to neurodegeneration. The most prominent candidates are ganglioside synthesis and impaired addition of O-linked β-N-acetylglucosamine (O-GlcNAc) groups to proteins important for axonal and synaptic function. Special consideration is given to examples where genetic mutations within glycosyltransferases are associated with neurodegeneration in recognition of the fact that these changes are likely to be upstream causes present from birth
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