Bank Capital, Liquidity and Systemic Risk

We analyze the impact of capital adequacy regulation on bank insolvency and aggregate investment. We develop a model of the banking system that is characterized by the interaction of many heterogeneous banks with the real sector, interbank credit relations as a consequence of bank liquidity management and an insolvency mechanism. This allows us to study the impact of capital adequacy regulation on systemic risk. In particular we can analyze the impact of regulation on contagious defaults arising from mutual credit relations. We show that the impact of capital adequacy on systemic stability is ambiguous and that systemic risk might actually increase as a consequence of imposing capital constraints on banks. Furthermore we analyze the indirect consequences of capital adequacy regulation that are transmitted to the real economy by their impact on equilibrium interbank rates and thus the opportunity costs of liquidity within the banking system.

Alliance '90/The Greens at the Crossroads: On Their Way to Becoming a Mainstream Party?

The Greens have been riding high in the polls for months now. In Baden-Württemberg, a stronghold of the Christian-Democratic Party (CDU), Winfried Kretschmann became the first Green party candidate to be elected Minister-President of any German state. This article looks beyond the current political climate to analyze longer-term trends in Green party support. The data used come from the Socio- Economic Panel (SOEP) Study, carried out by DIW Berlin in cooperation with TNS Infratest, Munich. The data are especially well suited to the in-depth analysis of party identification for two reasons: First, the SOEP has interviewed the same individuals on their party support for 27 consecutive years. Second, the SOEP provides a uniquely rich set of data on the question of who these Green partisans are-how much they earn, what educational qualifications they possess and what their occupational status is. Our results show that the successes of Alliance '90/The Greens in recent elections are the product of long-term changes in the party's electorate. From the 1980s until today, the Greens have enjoyed the over-proportional and uninterrupted support of younger voters. The party has also been successful in maintaining voter loyalty even as their supporters grow older. Furthermore, the results show that a large proportion of individuals who supported the Greens in their youth are now high-income earners, civil servants, salaried employees and self-employed. Because of this, Alliance '90/The Greens are now competing with the Christian Democratic Union (CDU) and Free Democratic Party (FDP) to represent the interests of affluent middle-class voters.Party identification, B90/Die Grünen, SOEP

Comment on "A test-tube model for rainfall" by Wilkinson M., EPL 106 (2014) 40001

This paper is a comment to M Wilkinson, EPL 106 (2014) 40001, arXiv:1401.4620 [physics.ao-ph,cond-mat.soft], which draws conclusion from our data that are at variance with our observations

Faraday effect in rippled graphene: Magneto-optics and random gauge fields

A beam of linearly polarized light transmitted through magnetically biased graphene can have its axis of polarization rotated by several degrees after passing the graphene sheet. This large Faraday effect is due to the action of the magnetic field on graphene's charge carriers. As deformations of the graphene membrane result in pseudomagnetic fields acting on the charge carriers, the effect of random mesoscopic corrugations (ripples) can be described as the exposure of graphene to a random pseudomagnetic field. We aim to clarify the interplay of these typically sample inherent fields with the external magnetic bias field and the resulting effect on the Faraday rotation. In principle, random gauge disorder can be identified from a combination of Faraday angle and optical spectroscopy measurements.Comment: 7 pages, 4 figure

Joint Image Reconstruction and Segmentation Using the Potts Model

We propose a new algorithmic approach to the non-smooth and non-convex Potts problem (also called piecewise-constant Mumford-Shah problem) for inverse imaging problems. We derive a suitable splitting into specific subproblems that can all be solved efficiently. Our method does not require a priori knowledge on the gray levels nor on the number of segments of the reconstruction. Further, it avoids anisotropic artifacts such as geometric staircasing. We demonstrate the suitability of our method for joint image reconstruction and segmentation. We focus on Radon data, where we in particular consider limited data situations. For instance, our method is able to recover all segments of the Shepp-Logan phantom from $7$ angular views only. We illustrate the practical applicability on a real PET dataset. As further applications, we consider spherical Radon data as well as blurred data