The asymptotic regimes of tilted Bianchi II cosmologies

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 $p = (\gamma -1) \mu$, where $\gamma$ 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 $\gamma > {10/7}$. 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

Exact Markovian kinetic equation for a quantum Brownian oscillator

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

Correlations of record events as a test for heavy-tailed distributions

A record is an entry in a time series that is larger or smaller than all previous entries. If the time series consists of independent, identically distributed random variables with a superimposed linear trend, record events are positively (negatively) correlated when the tail of the distribution is heavier (lighter) than exponential. Here we use these correlations to detect heavy-tailed behavior in small sets of independent random variables. The method consists of converting random subsets of the data into time series with a tunable linear drift and computing the resulting record correlations.Comment: Revised version, to appear in Physical Review Letter

Local picture-repetition mode detector for video de-interlacing

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

Gesundheitsforschung am DIW Berlin

Das Gesundheitssystem und die verschiedenen Gesundheitsmärkte sind durch eine Vielfalt von Merkmalen gekennzeichnet, die ein hohes Maß an staatlicher Regulierung erforderlich machen. Allen Teilen der Bevölkerung Zugang zu Gesundheitsleistungen zu verschaffen und dies wirtschaftlich effizient und finanzierbar zu gestalten, stellt eine politische Herausforderung dar, die im Zug der demografischen Alterung der Gesellschaft noch größer werden wird. Damit gewinnt auch die wissenschaftliche Analyse und Evaluation von gesundheitspolitischen Maßnahmen an Bedeutung. Das DIW Berlin wird seine gesundheitsökonomische und gesundheitssoziologische Forschung daher weiter ausbauen. Im Mittelpunkt steht dabei die Analyse staatlicher Interventionen im Gesundheitsbereich. Darüber hinaus werden die mit Gesundheit und Krankheit verbundenen Lebenslagen untersucht.The health system and the various healthcare markets are characterized by a number of special features requiring a high degree of government regulation. Giving all sections of the population access to healthcare services, and doing this cost-effectively and affordably, is a political challenge that will become even more difficult as a result of society's aging demographic. Consequently, the scientific analysis and evaluation of healthcare policy is becoming increasingly important. DIW Berlin will therefore further develop its economic and sociological research into health. It will focus on analyzing government intervention in the field of healthcare and how this affects the wellbeing of individuals

Stromal cells of the mouse spleen

The composition and function of stromal cells in the white pulp of the spleen resemble to a large extent the situation in other secondary lymphoid organs such as lymph nodes. The stromal cells play an important role in the support and guidance of lymphocytes and myeloid cells in the T and B cell zones of the spleen. Major differences of the spleen are found in the way cells enter the white pulp and the composition of stromal cells in the red pulp

Local picture-repetition mode detector for video de-interlacing

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

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

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.

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Dynamisch voeren verbetert inkomen altijd

Afhankelijk van de situatie kan een normaal melkveebedrijf nu al 0,7 tot 2 cent per kg melk verdienen met dynamisch voeren. Na afschaffen van het quotum kan dit nog meer worden. WUR Livestock Research heeft het systeem van dynamisch voeren in bedrijfsverband geëvalueerd en gekeken wat het effect is van verschillende melk- en krachtvoerprijzen op de krachtvoergift en voor het economisch resultaa