Basel III and CEO compensation in banks: pay structures as a regulatory signal : [March 6, 2013]

This paper proposes a new regulatory approach that implements capital requirements contingent on managerial compensation. We argue that excessive risk taking in the financial sector originates from the shareholder moral hazard created by government guarantees rather than from corporate governance failures within banks. The idea of the proposed regulation is to utilize the compensation scheme to drive a wedge between the interests of top management and shareholders to counteract shareholder risk-shifting incentives. The decisive advantage of this approach compared to existing regulation is that the regulator does not need to be able to properly measure the bank investment risk, which has been shown to be a difficult task during the 2008-2009 financial crisis

Interbank network and bank bailouts: Insurance mechanism for non-insured creditors? : [Version 20 Februar 2013]

This paper presents a theory that explains why it is beneficial for banks to engage in circular lending activities on the interbank market. Using a simple network structure, it shows that if there is a non-zero bailout probability, banks can significantly increase the expected repayment of uninsured creditors by entering into cyclical liabilities on the interbank market before investing in loan portfolios. Therefore, banks are better able to attract funds from uninsured creditors. Our results show that implicit government guarantees incentivize banks to have large interbank exposures, to be highly interconnected, and to invest in highly correlated, risky portfolios. This can serve as an explanation for the observed high interconnectedness between banks and their investment behavior in the run-up to the subprime mortgage crisis

Effect of deposition conditions and doping on the structure, optical properties and photocatalytic activity of d.c. magnetron sputtered TiO2 thin films

The main topic of this thesis was to investigate the relationship between the microstructure and the photocatalytic activity of TiO2 thin films, with respect to the catalytic breakdown of volatile organic compounds. TiO2 thin films were deposited by d.c. magnetron sputtering from sub-stoichiometric, ceramic TiO2 targets. The as deposited films were found to be amorphous, as determined by x-ray diffraction (XRD), and a post deposition anneal treatment was needed to crystallize the films in the anatase phase. The physical properties and photocatalytic activity of the as deposited as well as the annealed films were studied. The thin film porosity, as determined from the refractive index, was found to be influenced by the deposition conditions and to be a major factor controlling the photocatalytic activity of the thin films, together with the thin film crystallinity. A second topic of this thesis was to study the effect of additives on the microstructure and properties of the TiO2 thin films. Doped TiO2 thin films were prepared by d.c. magnetron sputtering from sub-stoichiometric, ceramic M2O3/ TiO2 mixed oxide targets (M = Fe, Nd, V) and by ion implantation of TiO2 thin films with Fe and Nd. The deposition conditions of the thin films were fixed and the effect of the additive concentration in the target as well as the ion dose during implantation on the thin film properties were studied. For the ceramic TiO2 as well as the mixed oxide targets the sputtering behavior in Ar and Ar/ O2 atmosphere was determined which allowed to control the thin film deposition process. Since stoichiometric thin films could be deposited without the addition of O2 to the sputter gas, the thin films used for further characterization were deposited in a pure Ar atmosphere. In order to determine the photocatalytic activity of the thin films towards the breakdown of volatile organic substances in air, a dedicated batch reactor for testing of thin films in a controlled atmosphere was designed and characterized. As a measure for the photocatalytic activity of the thin films, the initial breakdown rate of ethanol during UV illumination was used

Novel anion conductors - conductivity, thermodynamic stability and hydration of anion-substituted mayenite-type cage compounds C(12)A(7):X (X = O, OH, Cl, F, CN, S, N)

Mayenite (Ca12Al14O33) is a highly interesting functional material not only in view of its unique crystal structure as a cage compound but also for its variety of possible applications. Its ability to incorporate foreign ions into the cage structure opens the possibility to create new types of solid electrolytes and even electrides. Therefore, the conductivity of various anion substituted mayenites was measured as a function of temperature. Due to controversial reports on the stability of mayenite under specific thermodynamic conditions (dry, wet, reducing, and high temperature), a comprehensive study on the stability was performed. Mayenite is clearly not stable under dry conditions (ppm H2O < 100) at temperatures above 1050 degrees C, and thus, the mayenite phase vanishes from the calcium aluminate phase diagram below a minimum humidity. Two decomposition reactions were observed and are described in detail. To get further insight into the mechanism of hydration of mayenite, the conductivity was measured as a function of water vapour pressure in a range of -5 <= lg[pH(2)O/bar] <= -1.6 at temperatures ranging from 1000 degrees C <= theta <= 1200 degrees C. The hydration isotherms are described with high acuracy by the underlying point defect model, which is confirmed in a wide range of water vapour pressure

Regulation of taproot development and sucrose stabilization in sugar beet: Influence of invertase inhibitors and occurrence of mitochondrial energy-dissipating proteins

Die Zuckerrübe (Beta vulgaris) ist eine der wenigen Pflanzen, die große Mengen Saccharose speichert. Während der Entwicklung der Speicherwurzel akkumuliert Saccharose in den Vakuolen und kann in modernen Sorten einen Anteil von bis zu 20 % des Frischgewichtes erreichen. In der vorliegenden Arbeit wurde die Expression der wichtigsten Saccharose-spaltenden Enzyme bestimmt. Die Aktivität von Invertasen zeigt eine negative Korrelation zur Saccharoseanreicherung und während des Großteils der Speicherwurzelentwicklung werden lediglich Isoformen der Saccharose-Synthase und keine Invertasen exprimiert. Nach Verwundung werden eine Zellwand-lokalisierte und eine vakuolären Invertase induziert, wobei letztere für einen großen Teil der Saccharoseverluste nach der Ernte verantwortlich ist. Versuche die Aktivität dieser vakuolären Invertase durch Überexpression eines Invertaseinhibitors aus Tabak zu unterbinden erbrachten keine Verringerung der wundinduzierten Saccharosehydrolyse. Ein endogener Invertaseinhibitor der Zuckerrübe, BvC/VIF1 (Beta vulgaris cell wall or vacuolar inhibitor of beta-fructosidase), wurde identifiziert und funktionell charakterisiert. Der Inhibitor zeigt eine starke Expression während der Speicherrübenentwicklung und das rekombinant hergestellte BvC/VIF1-Protein zeigt eine hohe Affinität zu sauren Invertasen, insbesondere zu vakuolären Invertasen. Um mehr über die physiologische Rolle des Inhibitors während der Entwicklung der Zuckerrübenspeicherwurzel herauszufinden, wurde Versuche zur Verringerung der Expression dieses Gens unternommen. Außerdem wurden Zuckerrübenpflanzen hergestellt, die BvC/VIF1 vermehrt exprimieren. Erste Untersuchungen an diesen Pflanzen zeigten, dass es hierdurch zu einer signifikanten Verringerung der vakuolären Invertaseaktivität in Blättern kommt. Mittels eines gegen das BvC/VIF1-Protein erstelltem Antiserums wurden zwei Inhibitorproteine in Speicherwurzelextrakten nachgewiesen. Dahingegen trat in der Zellwand von Beta vulgaris Suspensionskulturzellen nur ein Protein auf. Von diesen drei Proteinen wurden partielle Peptidsequenzen ermittelt, die mit der bekannten BvC/VIF1-Sequenz übereinstimmten. In Blättern von transgenen, BvC/VIF1 überexprimierenden, Pflanzen wurden zwei Proteine beobachtet, die eine ähnliche Größe zeigen wie die in untransformierten Speicherwurzeln beobachteten und die in Blättern von Wildtyppflanzen nicht vorhanden sind. Dies deutet daraufhin, dass möglicherweise Proteine mit unterschiedlichen Größen durch die Translation eines einzelnen BvC/VIF1-Gens entstehen. Die subzelluläre Lokalisierung der Inhibitorproteine wurde mittels GFP-Fusionen analysiert. Die Fusionsproteine wurden entweder in der Vakuole beobachtet, was auf das Vorhandensein von vakuolären Sortierungssignalen hindeutet, oder aggregierten in Vesikel-artigen Strukturen. Weiterhin trat eine proteolytische Spaltung von Inhibitor-GFP Fusionen auf, die zum Nachweis von freiem Inhibitorprotein führte. Mittels differentieller Extraktion aus untransformierten Speicherwurzeln und Suspensionskulturzellen konnte gezeigt werden, dass das kleinere der beiden Inhibitorproteine in der Zellwand lokalisiert zu sein scheint. Um die Wechselwirkung zwischen Invertase und Inhibitor genauer zu untersuchen, wurde eine Zuckerrüben-Invertase rekombinant in Bakterien hergestellt und ihre enzymatischen Eigenschaften untersucht. Der Km-Wert der Invertase liegt im unteren millimolaren Bereich und das Enzym zeigt eine maximale Aktivität zwischen pH 4 und 6. Die Wechselwirkung mit dem Invertaseinhibitor ist ebenfalls in hohem Maße pH-abhängig und zeigt ein Maximum zwischen pH 4 und 5. Oberhalb von pH 6 kommt es zu keiner Bindung des Inhibitors an die Invertase. Da die pH-Bedingungen von zellulären Kompartimenten wie der Zellwand oder der Vakuole dynamischen Schwankungen unterliegen, handelt es sich hierbei möglicherweise um einen Regulationsmechanismus der Invertaseinaktivierung. In einem zweiten Projekt wurden erste Ergebnisse über das Vorhandensein und die Regulation von Proteinen, die die Effizienz der Atmung regulieren erzielt. Zwei Isoformen von sogenannten Uncoupling Proteinen werden konstitutiv in der Zuckerrübe exprimiert, während eine Induktion einer alternativen Oxidase nach Verwundung und Lagerung beobachtet wurde. Mitglieder beider Genfamilien sind mögliche Zielgene, die Saccharoseverluste während der Lagerung beeinflussen können. Sie dienen als Energie-Ableitungssysteme und ihre Aktivität kann die Respiration erhöhen, was einen vermehrten Saccharoseabbau zur Folge hat. Die ermittelten Ergebnisse weisen daraufhin, dass zumindest die alternative Oxidase eine starke Reaktion auf Verwundung und Lagerung zeigt

The model case of an oxygen storage catalyst - non-stoichiometry, point defects and electrical conductivity of single crystalline CeO2-ZrO2-Y2O3 solid solutions

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The ternary solid solution CeO2–ZrO2 is known for its superior performance as an oxygen storage catalyst in exhaust gas catalysis (e.g. TWC), although the defect chemical background of these outstanding properties is not fully understood quantitatively. Here, a comprehensive experimental study is reported regarding defects and defect-related transport properties of cubic stabilized single crystalline (CexZr1−x)0.8Y0.2O1.9−δ (0 ≤ x ≤ 1) solid solutions as a model system for CeO2–ZrO2. The constant fraction of yttria was chosen in order to fix a defined concentration of oxygen vacancies and to stabilize the cubic fluorite-type lattice for all Ce/Zr ratios. Measurements of the total electrical conductivity, the partial electronic conductivity, the ionic transference number and the non-stoichiometry (oxygen deficiency, oxygen storage capacity) were performed in the oxygen partial pressure range −25 < lg pO2/bar < 0 and for temperatures between 500 °C and 750 °C. The total conductivity at low pO2 is dominated by electronic transport. A strong deviation from the widely accepted ideal solution based point defect model was observed. An extended point defect model was developed using defect activities rather than concentrations in order to describe the point defect reactions in CeO2–ZrO2–Y2O3 properly. It served to obtain good quantitative agreement with the measured data. By a combination of values for non-stoichiometries and for electronic conductivities, the electron mobility could be calculated as a function of pO2, ranging between 10−2 cm2 V−1 s−1 and 10−5 cm2 V−1 s−1. Finally, the origin of the high oxygen storage capacity and superior catalytic promotion performance at a specific ratio of n(Ce)/n(Zr) ≈ 1 was attributed to two main factors: (1) a strongly enhanced electronic conductivity in the high and medium pO2 range qualifies the material to be a good mixed conductor, which is essential for a fast oxygen exchange and (2) the equilibrium constant for the reduction exhibits a maximum, which means that the reduction is thermodynamically most favoured just at this composition