Coronal lines and the warm X-ray absorber in Seyfert 1 Galaxies

The connection between the coronal lines and the warm absorber is examined systematically. In an earlier work it was found that the coronal line emitting plasma and the warm absorber gas share the same density and temperature. If there is a connection between the warm absorber gas and the forbidden high-ionization line (FHIL) plasma, one can use the profiles of coronal lines to derive the kinematics and dynamics of the warm absorber due to the high spectral resolution available in the optical range. Further support for a connection is a correlation between the equivalent width of [Fe X] 6375 and the ROSAT spectral index found for an optically selected sample. For X-ray selected objects with absorption edges observed by ASCA, we looked for a correlation between the coronal lines and the warm absorber gas. A direct correlation cannot be confirmed.Comment: Contributed talk presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho

A Market Based Measure of Credit Quality and Banks' Performance During the Subprime Crisis

We propose a new method for measuring the quality of banks credit portfolios. This method makes use of information impounded in bank share prices by exploiting differences in their sensitivity to credit default swap spreads of borrowers of varying quality. The method allows us to derive a credit risk indicator (CRI), which is the perceived share of high risk exposures in a bank's portfolio. We estimate CRIs for the 150 largest U.S. bank holding companies and find that they have strong predictive power for the BHCs' performance during the subprime crisis, even after controlling for a variety of traditional asset quality proxies. Interestingly, we also find that the BHCs' aggregate CRI did not deteriorate since the beginning of the subprime crisis. This suggests that the market was aware of their (average) exposure to high risk credit.credit risk;asset quality;banks;subprime crisis

Evolution of Feedback Loops in Oscillatory Systems

Feedback loops are major components of biochemical systems. Many systems show multiple such (positive or negative) feedback loops. Nevertheless, very few quantitative analyses address the question how such multiple feedback loops evolved. Based on published models from the mitotic cycle in embryogenesis, we build a few case studies. Using a simple core architecture (transcription, phosphorylation and degradation), we define oscillatory models having either one positive feedback or one negative feedback, or both loops. With these models, we address the following questions about evolvability: could a system evolve from a simple model to a more complex one with a continuous transition in the parameter space? How do new feedback loops emerge without disrupting the proper function of the system? Our results show that progressive formation of a second feedback loop is possible without disturbing existing oscillatory behavior. For this process, the parameters of the system have to change during evolution to maintain predefined properties of oscillations like period and amplitude.Comment: Proceedings of the 2009 FOSBE conference in Denver, CO, USA. 4 page

Fluid dynamics video of domains with spiral dislocations formed in the wake of an enslaved phase-separation front

Enslaved phase-separation fronts that move with a speed just smaller than that of a free front will leave in their wake a morphology of alternating domains that are roughly aligned with the front. However, these alternating domains will typically not be in phase initially. Instead there are defects. Here we present novel phase-separation morphologies that are formed in such systems where the defects are reminiscent of spiral dislocations in crystal growth.Comment: 1 pag

Corporate Social Responsibility in Large Family and Founder Firms

Based on arguments about long-term orientation and corporate reputation, we argue that family and founder firms differ from other firms with regard to corporate social responsibility. Using Bayesian analysis, we then show that family and founder ownership are associated with a lower level of corporate social responsibility concerns, whereas ownership by institutional investors is associated with a higher level of corporate social responsibility concerns and a lower level of corporate social responsibility initiatives. We conclude that it makes sense to distinguish between family, founder and institutional investors and their roles as owners or managers when analyzing the effects of corporate governance on corporate social responsibility.corporate social responsibility;family firms;family management;family ownership;founder firms;long-term orientation

Fermions in the pseudoparticle approach

The pseudoparticle approach is a numerical technique to compute path integrals without discretizing spacetime. The basic idea is to integrate over those field configurations, which can be represented by a sum of a fixed number of localized building blocks (pseudoparticles). In a couple of previous papers we have successfully applied the pseudoparticle approach to pure SU(2) Yang-Mills theory. In this work we discuss how to incorporate fermionic fields in the pseudoparticle approach. To test our method, we compute the phase diagram of the 1+1-dimensional Gross-Neveu model in the large-N limit.Comment: 11 pages, 10 figure