143 research outputs found

    Compressed representation of a partially defined integer function over multiple arguments

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    In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one

    Extra-Visual Functional and Structural Connection Abnormalities in Leber's Hereditary Optic Neuropathy

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    We assessed abnormalities within the principal brain resting state networks (RSNs) in patients with Leber's hereditary optic neuropathy (LHON) to define whether functional abnormalities in this disease are limited to the visual system or, conversely, tend to be more diffuse. We also defined the structural substrates of fMRI changes using a connectivity-based analysis of diffusion tensor (DT) MRI data. Neuro-ophthalmologic assessment, DT MRI and RS fMRI data were acquired from 13 LHON patients and 13 healthy controls. RS fMRI data were analyzed using independent component analysis and SPM5. A DT MRI connectivity-based parcellation analysis was performed using the primary visual and auditory cortices, bilaterally, as seed regions. Compared to controls, LHON patients had a significant increase of RS fluctuations in the primary visual and auditory cortices, bilaterally. They also showed decreased RS fluctuations in the right lateral occipital cortex and right temporal occipital fusiform cortex. Abnormalities of RS fluctuations were correlated significantly with retinal damage and disease duration. The DT MRI connectivity-based parcellation identified a higher number of clusters in the right auditory cortex in LHON vs. controls. Differences of cluster-centroid profiles were found between the two groups for all the four seeds analyzed. For three of these areas, a correspondence was found between abnormalities of functional and structural connectivities. These results suggest that functional and structural abnormalities extend beyond the visual network in LHON patients. Such abnormalities also involve the auditory network, thus corroborating the notion of a cross-modal plasticity between these sensory modalities in patients with severe visual deficits

    Network analysis of human glaucomatous optic nerve head astrocytes

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    <p>Abstract</p> <p>Background</p> <p>Astrocyte activation is a characteristic response to injury in the central nervous system, and can be either neurotoxic or neuroprotective, while the regulation of both roles remains elusive.</p> <p>Methods</p> <p>To decipher the regulatory elements controlling astrocyte-mediated neurotoxicity in glaucoma, we conducted a systems-level functional analysis of gene expression, proteomic and genetic data associated with reactive optic nerve head astrocytes (ONHAs).</p> <p>Results</p> <p>Our reconstruction of the molecular interactions affected by glaucoma revealed multi-domain biological networks controlling activation of ONHAs at the level of intercellular stimuli, intracellular signaling and core effectors. The analysis revealed that synergistic action of the transcription factors AP-1, vitamin D receptor and Nuclear Factor-kappaB in cross-activation of multiple pathways, including inflammatory cytokines, complement, clusterin, ephrins, and multiple metabolic pathways. We found that the products of over two thirds of genes linked to glaucoma by genetic analysis can be functionally interconnected into one epistatic network via experimentally-validated interactions. Finally, we built and analyzed an integrative disease pathology network from a combined set of genes revealed in genetic studies, genes differentially expressed in glaucoma and closely connected genes/proteins in the interactome.</p> <p>Conclusion</p> <p>Our results suggest several key biological network modules that are involved in regulating neurotoxicity of reactive astrocytes in glaucoma, and comprise potential targets for cell-based therapy.</p

    Search for new physics in the multijet and missing transverse momentum final state in proton-proton collisions at √s=8 Tev

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    Study of double parton scattering using W+2-jet events in proton-proton collisions at √s=7 TeV

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    Measurements of the tt¯ charge asymmetry using the dilepton decay channel in pp collisions at √s=7 TeV

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    Measurement of associated production of vector bosons and top quark-antiquark pairs in pp collisions at √s=7 TeV

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    PubMed ID: 23679709The first measurement of vector-boson production associated with a top quark-antiquark pair in proton-proton collisions at s √ =7  TeV is presented. The results are based on a data set corresponding to an integrated luminosity of 5.0  fb^−1 , recorded by the CMS detector at the LHC in 2011. The measurement is performed in two independent channels through a trilepton analysis of tt ¯ Z events and a same-sign dilepton analysis of tt ¯ V (V=W or Z ) events. In the trilepton channel a direct measurement of the tt ¯ Z cross section σ tt ¯ Z =0.28 [+0.14 −0.11]  (stat) [+0.06 −0.03]  (syst)  pb is obtained. In the dilepton channel a measurement of the tt ¯ V cross section yields σtt¯V=0.43 [+0.17 −0.15]  (stat) [+0.09 −0.07]  (syst)  pb . These measurements have a significance, respectively, of 3.3 and 3.0 standard deviations from the background hypotheses and are compatible, within uncertainties, with the corresponding next-to-leading order predictions of 0.137[+0.012 −0.016] and 0.306 [+0.031 −0.053]   pb

    Searches for new physics using the t(t)over-bar invariant mass distribution in pp collisions at √s=8 TeV

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    This is the pre-print version of the final published paper that is available from the link belowSearches for anomalous top quark-antiquark production are presented, based on pp collisions at √s=8  TeV . The data, corresponding to an integrated luminosity of 19:7 fb^-1, were collected with the CMS detector at the LHC. The observed tt invariant mass spectrum is found to be compatible with the standard model prediction. Limits on the production cross section times branching fraction probe, for the first time, a region of parameter space for certain models of new physics not yet constrained by precision measurements

    Measurement of the production cross section for Z gamma -> nu(nu)over-bar gamma in pp collisions at √s=7 TeV and limits on ZZ gamma and Z gamma gamma triple gauge boson couplings

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    This article is the pre-print version of the final published paper that is available from the link below.A measurement of the Z → vvγ cross section in pp collisions at root s = 7TeV is presented, using data corresponding to an integrated luminosity of 5.0 fb-1 collected with the CMS detector. This measurement is based on the observation of events with an imbalance of transverse energy in excess of 130 GeV and a single photon in the absolute pseudorapidity range |n| < 1:4 with transverse energy above 145 GeV. The Z →vvγ production cross section is measured to be 21.1±4.2 (stat:)±4.3 (syst:)±0.5 (lum:) fb, which agrees with the standard model prediction of 21.9±1.1 fb. The results are combined with the CMS measurement of Z production in the l+l- γ final state (where l is an electron or a muon) to yield the most stringent limits to date on triple gauge boson couplings: |hZ3|< 2.7 x 10-3, |hZ4| < 1,3 x 10-5 for ZZγ and |hγ3| < 2.9 x10-3, |hγ4| < 1.5 x 10-5 for Zγγ couplings
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