Electromagnetic radiation from nuclear collisions at RHIC energies

The hot and dense strongly interacting matter created in collisions of heavy nuclei at RHIC energies is modeled with relativistic hydrodynamics, and the spectra of real and virtual photons produced at mid-rapidity in these events are calculated. Several different sources are considered, and their relative importance is compared. Specifically, we include jet fragmentation, jet-plasma interactions, the emission of radiation from the thermal medium and from primordial hard collisions. Our calculations consistently take into account jet energy loss, as evaluated in the AMY formalism. We obtain results for the spectra, the nuclear modification factor (R_AA), and the azimuthal anisotropy (v_2) that agree with the photon measurements performed by the PHENIX collaboration at RHIC

Elliptic flow of thermal photons in relativistic nuclear collisions

We predict the transverse momentum (pT) dependence of elliptic flow of thermal photons for Au+Au collisions at the Relativistic Heavy Ion Collider. We model the system hydrodynamically, assuming formation of a thermalized quark-gluon plasma at some early time, followed by cooling through expansion, hadronization and decoupling. Photons are emitted throughout the expansion history. Contrary to hadron elliptic flow, which hydrodynamics predicts to increase monotonically with pT, the elliptic flow of thermal photons is predicted to first rise and then fall again as pT increases. Photon elliptic flow at high pT is shown to reflect the quark momentum anisotropy at early times when it is small, whereas at low pT it is controlled by the much larger pion momentum anisotropy during the late hadronic emission stage. An interesting structure is predicted at intermediate pT ~ 0.4 GeV/c where photon elliptic flow reflects the momenta and the (compared to pions) reduced v2 of heavy vector mesons in the late hadronic phase.Comment: 4 pages, 4 figures. Amended Fig. 3 and corresponding discussion, with complete explanation of the low-pT structure of photon elliptic flow around pT=400 MeV/

Fitted HBT radii versus space-time variances in flow-dominated models

The inability of otherwise successful dynamical models to reproduce the ``HBT radii'' extracted from two-particle correlations measured at the Relativistic Heavy Ion Collider (RHIC) is known as the ``RHIC HBT Puzzle.'' Most comparisons between models and experiment exploit the fact that for Gaussian sources the HBT radii agree with certain combinations of the space-time widths of the source which can be directly computed from the emission function, without having to evaluate, at significant expense, the two-particle correlation function. We here study the validity of this approach for realistic emission function models some of which exhibit significant deviations from simple Gaussian behaviour. By Fourier transforming the emission function we compute the 2-particle correlation function and fit it with a Gaussian to partially mimic the procedure used for measured correlation functions. We describe a novel algorithm to perform this Gaussian fit analytically. We find that for realistic hydrodynamic models the HBT radii extracted from this procedure agree better with the data than the values previously extracted from the space-time widths of the emission function. Although serious discrepancies between the calculated and measured HBT radii remain, we show that a more ``apples-to-apples'' comparison of models with data can play an important role in any eventually successful theoretical description of RHIC HBT data.Comment: 12 pages, 16 color figure

Novel immune cell-based therapies for atherosclerosis

Atherosclerosis is the main underlying pathology of cardiovascular disease, the largest single cause of death in industrialized countries, and current treatment is still largely insufficient. In recent years it has become evident that immune responses contribute to atherosclerosis. Therefore, during my PhD studies I focused on developing a therapy to induce and expand anti-inflammatory immune cells to reduce ongoing immune responses and atherosclerosis. I used the approach of cellular therapy and examined the effect of several different anti-inflammatory immune cells. For example, I made use of mesenchymal stem cells, which have previously been used to improve cardiac repair after myocardial infarction and were found to have anti-inflammatory properties. Additionally, I used drugs, e.g. inhibitors of protein degradation, and biologics, e.g. components of heat-killed bacteria, to directly increase the amount of anti-inflammatory immune cells. An interesting side-effect of some treatments was that they additionally reduced cholesterol levels. In summary, I have shown in pre-clinical models that immune cell-based therapies are promising for the treatment of atherosclerosis. As atherosclerosis is determined by both high cholesterol levels and inflammation reducing immune responses will greatly contribute to a better treatment of cardiovascular patients in the (near) future.Dutch Heart Foundation Peprotech Greiner Bio-One BD Biosciences Leiden UniversityUBL - phd migration 201

Wer arbeitet wie viel? Entscheidungen über den Erwerbsumfang im Partnerschaftskontext

"Um die Entscheidung über den Erwerbsumfang im Partnerschaftskontext anhand zweier konkurrierender mikroökonomischer Theorien zu untersuchen, muss die derzeitige Erwerbskonstellation berücksichtigt werden. Denn je nach theoretischem Ansatz kann sie einerseits die aktuelle Spezialisierungslogik vorgeben, die fortgeschrieben werden soll (Neue Haushaltsökonomie), oder andererseits die paarinternen Machtverhältnisse bestimmen, die möglichst zugunsten der eigenen Position verändert werden sollen (Verhandlungstheorie). Im vorliegenden Beitrag wird die Frage nach dem Einfluss der bisherigen Erwerbskonstellation auf die Entscheidung für zukünftige Erwerbskonstellationen untersucht. Dazu wird auf ein Faktorielles Survey-Design im Panel "Arbeitsmarkt und soziale Sicherung" (PASS) zur Erfassung der Stellenannahmebereitschaft zurückgegriffen. Es zeigt sich, dass Personen in Paarhaushalten vor allem an einem Ausgleich der Machtstruktur interessiert sind und sich nicht für eine Fortschreibung bestehender Spezialisierungen entscheiden." (Autorenreferat)"Investigating employment decisions in couples by two competing microeconomic theories requires attention to the current employment situation. Depending on the theoretical approach, the current employment constellation either prescribes current specialization strategies by the partners which have to be constantly updated (new home economics). Or it determines the bargaining power structure that each partner wants to optimize for his or her own benefit (bargaining theory). In this paper, the influence of the current employment constellation on desired future constellation is analyzed. A factorial survey module was implemented in the panel study 'Labour Market and Social Security' (PASS). In this module, respondents evaluated the willingness to accept hypothetical job offers. Results support hypotheses from bargaining theory: People are interested in achieving an equal power structure in their relationships. They do not favor to continue existing specializations as new home economics would predict." (author's abstract

'Single Nucleotide Polymorphisms' des Asparaginsynthetase-Gens

In dieser Untersuchung wurden Methoden zum Nachweis von drei nicht-synonymen SNPs im Asparaginsynthetase-Gen etabliert und deren Vorkommen untersucht. Mit Hilfe von Restriktionsenzymen wurden die SNP rs1049674 und rs3179866 des Gens der AS untersucht. Der SNP rs2070159 wurde mittels Allelspezifischer-Real-Time-PCR analysiert. Das Untersuchungsmaterial entstammte 36 pädiatrisch hämato-onkologischen Patienten, die unter ASPase-Therapie teilweise Nebenwirkungen erlitten, acht leukämischen Zelllinien und 31 Blutspendern. Die SNPs rs2070159 und rs3179866 ließen sich in keiner der Proben nachweisen. Der SNP rs1049674 war im hämato-onkologischen Kollektiv zu 44 %, im Blutspenderkollektiv zu 48 %, im Nebenwirkungskollektiv zu 60 % und im nebenwirkungsfreien Kollektiv zu 20 % vorhanden. Eine Korrelation von ASPase-Resistenz, AS-Expressionslevel und SNPs konnte nicht gefunden werden. Die Häufung des SNP rs1049674 im Nebenwirkungskollektiv sollte anhand einer größeren Fallzahl überprüft werden

Evolution of pion HBT radii from RHIC to LHC -- Predictions from ideal hydrodynamics

We present hydrodynamic predictions for the charged pion HBT radii for a range of initial conditions covering those presumably reached in Pb+Pb collisions at the LHC. We study central (b=0) and semi-central (b=7fm) collisions and show the expected increase of the HBT radii and their azimuthal oscillations. The predicted trends in the oscillation amplitudes reflect a change of the final source shape from out-of-plane to in-plane deformation as the initial entropy density is increased.Comment: 6 pages, incl. 5 figures. Contribution to the CERN Theory Institute Workshop "Heavy Ion Collisions at the LHC -- Last Call for Predictions", CERN, 14 May - 8 June 2007, to appear in J. Phys.

Elliptic flow of thermal photons and dileptons

In this talk we describe the recently discovered rich phenomenology of elliptic flow of electromagnetic probes of the hot matter created in relativistic heavy-ion collisions. Using a hydrodynamic model for the space-time dynamics of the collision fireball created in Au+Au collisions at RHIC, we compute the transverse momentum spectra and elliptic flow of thermal photons and dileptons. These observables are shown to provide differential windows into various stages of the fireball expansion.Comment: 8 pages, including 9 figures. Invited talk at the Hard Probes 2006 Conference (Asilomar, June 9-16, 2006), to appear in the Proceedings (Elsevier

Photon HBT interferometry for non-central heavy-ion collisions

Currently, the only known way to obtain experimental information about the space-time structure of a heavy-ion collision is through 2-particle momentum correlations. Azimuthally sensitive HBT interferometry (Hanbury Brown-Twiss intensity interferometry) can complement elliptic flow measurements by constraining the spatial deformation of the source and its time evolution. Performing these measurements on photons allows us to access the fireball evolution at earlier times than with hadrons. Using ideal hydrodynamics to model the space-time evolution of the collision fireball, we explore theoretically various aspects of 2-photon intensity interferometry with transverse momenta up to 2 GeV, in particular the azimuthal angle dependence of the HBT radii in non-central collisions. We highlight the dual nature of thermal photon emission, in both central and non-central collisions, resulting from the superposition of QGP and hadron resonance gas photon production. This signature is present in both the thermal photon source function and the HBT radii extracted from Gaussian fits of the 2-photon correlation function.Comment: 18 pages, 12 figure

Chancengleichheit am Arbeitsplatz

Die Partizipation von Frauen am Arbeitsmarkt hat in den letzten Jahrzehnten in Deutschland stark zugenommen, z.B. ist die Erwerbstätigenquote von Frauen mit knapp 70 Prozent im Jahr 2013 derjenigen der Männer (78 Prozent) bereits sehr nah. Trotzdem gibt es nach wie vor signifikante Geschlechterunterschiede im Hinblick auf das Arbeitsvolumen, die Löhne und Gehälter sowie die Karrierepositionen. Der Sonderbericht "Chancengleichheit am Arbeitsplatz" stellt dazu Daten aus der Forschungsstudie "Arbeitsqualität und wirtschaftlicher Erfolg" dar, die zum Ziel hat, mögliche Zusammenhänge zwischen der Arbeitsqualität der Beschäftigten und dem wirtschaftlichen Erfolg von Betrieben zu untersuchen. Sie wird vom Bundesministerium für Arbeit und Soziales (BMAS) und vom Institut für Arbeitsmarkt- und Berufsforschung (IAB) getragen und vom IAB, vom Seminar für Allgemeine Betriebswirtschaftslehre und Personalwirtschaftslehre der Universität zu Köln, dem Lehrstuhl für Managerial Accounting der Eberhard Karls Universität Tübingen und vom Zentrum für Europäische Wirtschaftsforschung (ZEW) durchgeführt. Es handelt sich um eine Längsschnittstudie, in der mittlerweile in der vierten Befragungswelle jeweils eine Betriebs- und eine Beschäftigtenbefragung durchgeführt wird. Der Sonderbericht "Chancengleichheit am Arbeitsplatz" zeigt, wie sich Frauen und Männer unter Berücksichtigung ihrer Heterogenität hinsichtlich soziodemografischer, beruflicher sowie betrieblicher Merkmale bei Führungspositionen sowie Instrumenten der Personalentwicklung unterscheiden. Eine Besonderheit ist dabei die zusätzliche Berücksichtigung von Persönlichkeitsmerkmalen