5,855 research outputs found

    Exact Markovian kinetic equation for a quantum Brownian oscillator

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    We derive an exact Markovian kinetic equation for an oscillator linearly coupled to a heat bath, describing quantum Brownian motion. Our work is based on the subdynamics formulation developed by Prigogine and collaborators. The space of distribution functions is decomposed into independent subspaces that remain invariant under Liouville dynamics. For integrable systems in Poincar\'e's sense the invariant subspaces follow the dynamics of uncoupled, renormalized particles. In contrast for non-integrable systems, the invariant subspaces follow a dynamics with broken-time symmetry, involving generalized functions. This result indicates that irreversibility and stochasticity are exact properties of dynamics in generalized function spaces. We comment on the relation between our Markovian kinetic equation and the Hu-Paz-Zhang equation.Comment: A few typos in the published version are correcte

    The asymptotic regimes of tilted Bianchi II cosmologies

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    In this paper we give, for the first time, a complete description of the dynamics of tilted spatially homogeneous cosmologies of Bianchi type II. The source is assumed to be a perfect fluid with equation of state p=(γ1)μp = (\gamma -1) \mu, where γ\gamma is a constant. We show that unless the perfect fluid is stiff, the tilt destabilizes the Kasner solutions, leading to a Mixmaster-like initial singularity, with the tilt being dynamically significant. At late times the tilt becomes dynamically negligible unless the equation of state parameter satisfies γ>10/7\gamma > {10/7}. We also find that the tilt does not destabilize the flat FL model, with the result that the presence of tilt increases the likelihood of intermediate isotropization

    Motion compensated De-interlacing with Film Mode Adaptation.

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    The invention relates to a method for de-interlacing a hybrid video sequence using at least one estimated motion vector for interpolating pixels. Field for petition patents, typically occurring in film originated video material, disturb the function of de-interlacing algorithm designed to convert interlaced video single into progressively scanned video. Therefore a mode decision has to be applied for local adaptation to the film/video mode, which is possible by defining values for a first motion vector and a second motion vector, calculating at least one first pixel using at least one pixel of previous image and one first motion vector, calculating at least one second pixel using at least one pixel of a next image and one second motion vector, calculating a reliability of said first and the second motion vector by comparing at least said first pixel with at least said second pixel the first and said second motion vectors being pre-defined for said calculation of reliability, and estimation an actual value for a motion vector, which turned out to be most reliable for de-interlacing said image

    Motion compensated De-interlacing with Film Mode Adaptation.

    Get PDF
    The invention relates to a method for de-interlacing a hybrid video sequence using at least one estimated motion vector for interpolating pixels. Field for petition patents, typically occurring in film originated video material, disturb the function of de-interlacing algorithm designed to convert interlaced video single into progressively scanned video. Therefore a mode decision has to be applied for local adaptation to the film/video mode, which is possible by defining values for a first motion vector and a second motion vector, calculating at least one first pixel using at least one pixel of previous image and one first motion vector, calculating at least one second pixel using at least one pixel of a next image and one second motion vector, calculating a reliability of said first and the second motion vector by comparing at least said first pixel with at least said second pixel the first and said second motion vectors being pre-defined for said calculation of reliability, and estimation an actual value for a motion vector, which turned out to be most reliable for de-interlacing said image

    Uncovering regulatory pathways that affect hematopoietic stem cell function using 'genetical genomics'

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    We combined large-scale mRNA expression analysis and gene mapping to identify genes and loci that control hematopoietic stem cell (HSC) function. We measured mRNA expression levels in purified HSCs isolated from a panel of densely genotyped recombinant inbred mouse strains. We mapped quantitative trait loci (QTLs) associated with variation in expression of thousands of transcripts. By comparing the physical transcript position with the location of the controlling QTL, we identified polymorphic cis-acting stem cell genes. We also identified multiple trans-acting control loci that modify expression of large numbers of genes. These groups of coregulated transcripts identify pathways that specify variation in stem cells. We illustrate this concept with the identification of candidate genes involved with HSC turnover. We compared expression QTLs in HSCs and brain from the same mice and identified both shared and tissue-specific QTLs. Our data are accessible through WebQTL, a web-based interface that allows custom genetic linkage analysis and identification of coregulated transcripts.

    Local picture-repetition mode detector for video de-interlacing

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    The de-interlacing of video material converted from film can be perfect, provided it is possible to recognize the field-pairs that originate from the same film image. Various so-called film-detectors have been proposed for this purpose, mainly in the patent-literature. Typically, these detectors fail in cases where video overlays are merged with film material, or when nonstandard repetition patterns are used. Both problems occur frequently in television broadcast. For these hybrid and/or irregular cases, we propose a detector that can detect different picture-repetition patterns locally in the image. This detector combines fuzzy logic rules and spatio-temporal prediction to arrive at a highly robust decision signal, suitable for pixel-accurate de-interlacing of hybrid and irregular video material. In addition to an evaluation of the performance, the paper also provides a complexity analysis.Peer Reviewe
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