The Economics of Solicited and Unsolicited Credit Ratings

This paper develops a dynamic rational expectations model of the credit rating process, incorporating three critical elements of this industry: (i) the rating agencies' ability to misreport the issuer's credit quality, (ii) their ability to issue unsolicited ratings, and (iii) their reputational concerns. We analyze the incentives of credit rating agencies to issue unsolicited credit ratings and the effects of this practice on the agencies' rating strategies. We nd that the issuance of unfavorable unsolicited credit ratings enables rating agencies to extract higher fees from issuers by credibly threatening to punish those that refuse to acquire a rating. Also, issuing unfavorable unsolicited ratings increases the rating agencies' reputation by demonstrating to investors that they resist the temptation to issue in ated ratings. In equilibrium, unsolicited credit ratings are lower than solicited ratings, because all favorable ratings are solicited; however, they do not have a downward bias. We show that, under certain conditions, a credit rating system that incorporates unsolicited ratings leads to more stringent rating standards

A versatile optode system for oxygen, carbon dioxide, and pH measurements in seawater with integrated battery and logger

Herein, we present a small and versatile optode system with integrated battery and logger for monitoring of O-2, pH, and pCO(2) in seawater. Three sensing materials designed for seawater measurements are optimized with respect to dynamic measurement range and long-term stability. The spectral properties of the sensing materials were tailored to be compatible with a commercially available laboratory oxygen logger that was fitted into a pressure housing. Interchangeable sensor caps with appropriate "sensing chemistry" are conveniently attached to the end of the optical fiber. This approach allows using the same instrument for multiple analytes, which offers great flexibility and minimizes hardware costs. Applications of the new optode system were demonstrated by recording depth profiles for the three parameters during a research cruise in the Baltic Sea and by measuring surface water transects of pH. The optode was furthermore used to monitor the concentration of dissolved oxygen in a seagrass meadow in the Limfjord, Denmark, and sensor packages consisting of pO(2), pH, and pCO(2) were deployed in the harbors of Kiel, Germany, and Southampton, England, for 6 d. The measurements revealed that the system can resolve typical patterns in seawater chemistry related to spatial heterogeneities as well as temporal changes caused by biological and tidal activity

PiggyBac transposon tools for recessive screening identify B-cell lymphoma drivers in mice.

B-cell lymphoma (BCL) is the most common hematologic malignancy. While sequencing studies gave insights into BCL genetics, identification of non-mutated cancer genes remains challenging. Here, we describe PiggyBac transposon tools and mouse models for recessive screening and show their application to study clonal B-cell lymphomagenesis. In a genome-wide screen, we discover BCL genes related to diverse molecular processes, including signaling, transcriptional regulation, chromatin regulation, or RNA metabolism. Cross-species analyses show the efficiency of the screen to pinpoint human cancer drivers altered by non-genetic mechanisms, including clinically relevant genes dysregulated epigenetically, transcriptionally, or post-transcriptionally in human BCL. We also describe a CRISPR/Cas9-based in vivo platform for BCL functional genomics, and validate discovered genes, such as Rfx7, a transcription factor, and Phip, a chromatin regulator, which suppress lymphomagenesis in mice. Our study gives comprehensive insights into the molecular landscapes of BCL and underlines the power of genome-scale screening to inform biology

Endogenous Liquidity Cycles

Abstract This paper presents a theory of liquidity cycles based on endogenous fluctuations in economic activity and the availability of informed capital. Risky assets are illiquid due to adverse selection. The degree of adverse selection and hence the liquidity of these assets depends on the endogenous information structure in the market. Liquidity provision is modeled as a repeated game with imperfect public monitoring. We construct a triggerstrategy equilibrium along the lines of Rather, fluctuations in liquidity arise endogenously from the need to create incentives for investors to engage in costly information production

Geodatenmanagement und -dienste am Beispiel des Tsunami-Frühwarnsystems für den Indischen Ozean

In dem vom BMBF geförderten Projekt GITEWS, dem Deutschen Beitrag zum Aufbau eines Tsunami Frühwarnsystems im Indischen Ozean, wird ein Geodaten Repository erstellt. Dieses Repository enthält alle Geodaten, die zur Entwicklung und Implementierung von GITEWS benötigt, und zum großen Teil von den deutschen und indonesischen Projektpartnern bereitgestellt werden. In der Phase der Anforderungsanalyse erfolgte eine Zusammenstellung aller verfügbaren und relevanten Daten für das System. Dieser Vorgang wurde in enger Zusammenarbeit mit den indonesischen Partnerorganisationen durchgeführt, um so gewährleisten zu können, dass bestehende Datensätze harmonisiert und integriert werden können. Die Geodaten werden in Geobasisdaten( Topographie, digitale Gelände- bzw. Oberflächenmodelle), Fernerkundungsdatendaten, und Geofachdaten (sozioökonomische Daten) untergliedert. Der Zugriff auf die Geodaten im GITEWSProjekt soll über ein Geodaten Repository auf OGC-konformen Diensten (WMS, WFS, WCS, CSW 2.0) erfolgen. Dieses Vorgehen ermöglicht allen Benutzern einen interoperablen Zugriff auf alle projektbezogenen Geodaten über das Internet