Control of unstable steady states by extended time-delayed feedback

Time-delayed feedback methods can be used to control unstable periodic orbits as well as unstable steady states. We present an application of extended time delay autosynchronization introduced by Socolar et al. to an unstable focus. This system represents a generic model of an unstable steady state which can be found for instance in a Hopf bifurcation. In addition to the original controller design, we investigate effects of control loop latency and a bandpass filter on the domain of control. Furthermore, we consider coupling of the control force to the system via a rotational coupling matrix parametrized by a variable phase. We present an analysis of the domain of control and support our results by numerical calculations.Comment: 11 pages, 16 figure

Direct photons ~basis for characterizing heavy ion collisions~

After years of experimental and theoretical efforts, direct photons become a strong and reliable tool to establish the basic characteristics of a hot and dense matter produced in heavy ion collisions. The recent direct photon measurements are reviewed and a future prospect is given.Comment: 8 pages, 8 figures, Invited plenary talk at Quark Matter 200

Heavy-flavor dynamics in nucleus-nucleus collisions: from RHIC to LHC

The stochastic dynamics of c and b quarks in the fireball created in nucleus-nucleus collisions at RHIC and LHC is studied employing a relativistic Langevin equation, based on a picture of multiple uncorrelated random collisions with the medium. Heavy-quark transport coefficients are evaluated within a pQCD approach, with a proper HTL resummation of medium effects for soft scatterings. The Langevin equation is embedded in a multi-step setup developed to study heavy-flavor observables in pp and AA collisions, starting from a NLO pQCD calculation of initial heavy-quark yields, complemented in the nuclear case by shadowing corrections, k_T-broadening and nuclear geometry effects. Then, only for AA collisions, the Langevin equation is solved numerically in a background medium described by relativistic hydrodynamics. Finally, the propagated heavy quarks are made hadronize and decay into electrons. Results for the nuclear modification factor R_AA of heavy-flavor hadrons and electrons from their semi-leptonic decays are provided, both for RHIC and LHC beam energies.Comment: 4 pages, 2 figures (3 eps files); submitted for publication in the proceedings of "Quark Matter 2011", 23-28 May 2011, Annecy (France

Overview of experimental results in PbPb collisions at sqrt{s_NN} = 2.76 TeV by the CMS Collaboration

The CMS experiment at the LHC is a general-purpose apparatus with a set of large acceptance and high granularity detectors for hadrons, electrons, photons and muons, providing unique capabilities for both proton-proton and ion-ion collisions. The data collected during the November 2010 PbPb run at sqrt{s_NN} = 2.76 TeV was analyzed and multiple measurements of the properties of the hot and dense matter were obtained. Global event properties, detailed study of jet production and jet properties, isolated photons, quarkonia and weak bosons were measured and compared to pp data and Monte Carlo simulations.Comment: 8 pages, 10 figures, proceedings for Quark Matter 2011, Annecy, France, May 23-28, 201

Summary of Experimental Results: Photons, Leptons and Heavy Quarks

This is a summary of experimental results on photons, leptons, and heavy quarks presented at Quark Matter 2008. A first measurement of the bottom to charm contribution to the lepton spectrum has given experimental indication for the suppression of charm and bottom. Excess dileptons have been observed and studied by both NA60 and PHENIX, which may arise from the early production of thermal dileptons and/or the modification of mesons.Comment: 11 pages, 9 figures, Summary talk at Quark Matter 200

Интерактивная обработка изображений, получаемых посредством лазерного монитора в режиме реального времени

В ходе исследования необходимо было создать устройство позиционирования объекта в системе лазерного монитора. В процессе исследования проводилось исследование алгоритмов определения резкости изображения. На основе выбранного метода был разработан алгоритм автоматической фокусировки изображения. Также был разработан алгоритм системы слежения за объектом на основе алгоритма нормированной кросскорреляции. В результате исследования удалось снизить искажения, вносимые оптической системой лазерного монитора и активной оптической средой, и организовать систему автоматической фокусировки изображения и систему слежения, позволяющую отслеживать перемещение объекта наблюдения с точностью до 1 пикселя.In the study, it was necessary to create a device object positioning system for the laser monitor. The study surveyed algorithms determine the sharpness of the image. Based on the selected method algorithm for automatic focus of the image was developed. There was also designeded a tracking system for the object of the algorithm based on normalized cross-correlation method. The study was able to reduce the distortions introduced by the optical system of the laser and monitor the active optical medium, and to organize a system of auto focus and image tracking system to track the movement of the object of observation up to 1 pixel

Gene expression evolution in pattern-triggered immunity within Arabidopsis thaliana and across Brassicaceae species

Plants recognize surrounding microbes by sensing microbe-associated molecular patterns (MAMPs) to activate pattern-triggered immunity (PTI). Despite their significance for microbial control, the evolution of PTI responses remains largely uncharacterized. Here, by employing comparative transcriptomics of six Arabidopsis thaliana accessions and three additional Brassicaceae species to investigate PTI responses, we identified a set of genes that commonly respond to the MAMP flg22 and genes that exhibit species-specific expression signatures. Variation in flg22-triggered transcriptome responses across Brassicaceae species was incongruent with their phylogeny, while expression changes were strongly conserved within A. thaliana. We found the enrichment of WRKY transcription factor binding sites in the 5′-regulatory regions of conserved and species-specific responsive genes, linking the emergence of WRKY-binding sites with the evolution of gene expression patterns during PTI. Our findings advance our understanding of the evolution of the transcriptome during biotic stress

Heavy-flavour and quarkonium production in the LHC era: from proton-proton to heavy-ion collisions

This report reviews the study of open heavy-flavour and quarkonium production in high-energy hadronic collisions, as tools to investigate fundamental aspects of Quantum Chromodynamics, from the proton and nucleus structure at high energy to deconfinement and the properties of the Quark-Gluon Plasma. Emphasis is given to the lessons learnt from LHC Run 1 results, which are reviewed in a global picture with the results from SPS and RHIC at lower energies, as well as to the questions to be addressed in the future. The report covers heavy flavour and quarkonium production in proton-proton, proton-nucleus and nucleus-nucleus collisions. This includes discussion of the effects of hot and cold strongly interacting matter, quarkonium photo-production in nucleus-nucleus collisions and perspectives on the study of heavy flavour and quarkonium with upgrades of existing experiments and new experiments. The report results from the activity of the SaporeGravis network of the I3 Hadron Physics programme of the European Union 7th Framework Programme