2,423 research outputs found

    Dimensionality reduction of clustered data sets

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    We present a novel probabilistic latent variable model to perform linear dimensionality reduction on data sets which contain clusters. We prove that the maximum likelihood solution of the model is an unsupervised generalisation of linear discriminant analysis. This provides a completely new approach to one of the most established and widely used classification algorithms. The performance of the model is then demonstrated on a number of real and artificial data sets

    NLO QCD corrections to the production of a weak boson pair associated by a hard jet

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    In this talk we discuss recent progress concerning precise predictions for the LHC. We give a status report of an application of the GOLEM method to deal with multi-leg one-loop amplitudes, namely the next-to-leading order QCD corrections to the process pp to V V + jet, where V is a weak boson W,Z.Comment: Talk at 2008 Rencontres de Moriond, QCD session, La Thuile, March 2007. Four page

    Verdi’s six-fours and la parola scenica

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    Verdi’s operas display many non-normative six-four chords. The question for the opera analyst, however, is not only what occurs musically, but why it does. Is there a dramatic function being served by this mix of harmonic-intervallic instability? We discuss four types of non-normative six-fours in Verdi: the arrival, wonder, evasion, and dissolving. But, even as we individuate these types, we note that they are all similar in one regard: they are all linked to a crucial dramatic statement that Verdi termed la parola scenica, a textual-musical signal that makes a dramatic situation suddenly evident

    Categorial mirror symmetry for K3 surfaces

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    We study the structure of a modified Fukaya category F(X){\frak F}(X) associated with a K3 surface XX, and prove that whenever XX is an elliptic K3 surface with a section, the derived category of \fF(X) is equivalent to a subcategory of the derived category D(X^){\bold D}(\hat X) of coherent sheaves on the mirror K3 surface X^\hat X.Comment: 11 pages, AmsLatex. Exposition (hopefully) improved, one argument simplifie

    Motivo e forma nel terzo movimento della Sonata op. 27 n. 2

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    Schenkerian analysis of Beethoven's Piano Sonata op. 27 n. 2, third movemen

    Il Gradus as Parnassum di Fedele Fenaroli

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    Illustrates the structure and goals of the treatise Regole e partimenti by Fedele Fenarol

    Parameter estimation and inference for stochastic reaction-diffusion systems: application to morphogenesis in D. melanogaster

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    Background: Reaction-diffusion systems are frequently used in systems biology to model developmental and signalling processes. In many applications, count numbers of the diffusing molecular species are very low, leading to the need to explicitly model the inherent variability using stochastic methods. Despite their importance and frequent use, parameter estimation for both deterministic and stochastic reaction-diffusion systems is still a challenging problem. Results: We present a Bayesian inference approach to solve both the parameter and state estimation problem for stochastic reaction-diffusion systems. This allows a determination of the full posterior distribution of the parameters (expected values and uncertainty). We benchmark the method by illustrating it on a simple synthetic experiment. We then test the method on real data about the diffusion of the morphogen Bicoid in Drosophila melanogaster. The results show how the precision with which parameters can be inferred varies dramatically, indicating that the ability to infer full posterior distributions on the parameters can have important experimental design consequences. Conclusions: The results obtained demonstrate the feasibility and potential advantages of applying a Bayesian approach to parameter estimation in stochastic reaction-diffusion systems. In particular, the ability to estimate credibility intervals associated with parameter estimates can be precious for experimental design. Further work, however, will be needed to ensure the method can scale up to larger problems

    The geometry of dual isomonodromic deformations

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    The JMMS equations are studied using the geometry of the spectral curve of a pair of dual systems. It is shown that the equations can be represented as time-independent Hamiltonian flows on a Jacobian bundle

    NLO QCD corrections to ZZ+jet production at hadron colliders

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    A fully differential calculation of the next-to-leading order QCD corrections to the production of Z-boson pairs in association with a hard jet at the Tevatron and LHC is presented. This process is an important background for Higgs particle and new physics searches at hadron colliders. We find sizable corrections for cross sections and differential distributions, particularly at the LHC. Residual scale uncertainties are typically at the 10% level and can be further reduced by applying a veto against the emission of a second hard jet. Our results confirm that NLO corrections do not simply rescale LO predictions.Comment: 15 pages, 4 figures, 4 tables; added 1 reference, version to appear in Phys. Lett.
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