In Böcker and Klüppelberg (2005) we presented a simple approximation of OpVaR of a single operational risk cell. The present paper derives approximations of similar quality and simplicity for the multivariate problem. Our approach is based on modelling of the dependence structure of different cells via the new concept of a Lévy copula. JEL Classifications: G18,G39.

The wave type field equation θ = λθ, where θ is a coframe field on a space-time, was recently proposed to describe the gravity field. This equation has a unique static, spherical-symmetric, asymptotically-flat solution, which leads to the viable Yilmaz-Rosen metric. We show that the wave type field equation is satisfied by the pseudo-conformal frame if the conformal factor is determined by a sc...

This essay assesses the relationship between farm size and productivity. Both parametric and nonparametric methods are used to derive efficiency measures. Smaller farms are found to have higher net farm income per hectare, and to be more technically efficient, than larger farms. JEL Classifications: Q12, O12

We compare the behavior of car mechanics and college students as sellers in experimental credence goods markets. Finding largely similar behavior, we note much more overtreatment by car mechanics, probably due to decision heuristics they learned in their professional training. JEL classifications: C91, D82, C72

This paper evaluates the hypothesis that during the 2008-2009 collapse in international trade, imports of higher quality goods experienced larger reductions compared to low-quality imports, using data on U.S. imports disaggregated by HS-10 product category and source country. We find little, if any, robust econometric evidence in support of this hypothesis. JEL Classifications: F41, F42

Fraud is an ancient crime and one that annually causes hundreds of billions of dollars in losses. We examine the behavioral patterns over time of different types of frauds, which illustrate cyclical frequencies. We develop an evolutionary theory that suggests cyclic behavior in frauds should be common. JEL classifications: D92, L15, P17

We investigate how the relative contribution of external factors to stock price movements varies with the degree of financial development. We find that financial development makes stock markets more susceptible to external influences (both financial and macroeconomic). Interestingly, this effect is present even after having accounted for capital controls and international trade effects. JEL Cla...

We study low-speed flows of a highly compressible, single-phase fluid in the presence of gravity, for example, in a regime appropriate for modeling recent spaceshuttle experiments on fluids near the liquid-vapor critical point. In the equations of motion, we include forces due to capillary stresses that arise from a contribution made by strong density gradients to the free energy. We derive for...

Using the coherent-state representation we show that the classical Einstein equation for the FRW cosmological model with a general minimal scalar field can be derived from the semiclassical quantum Einstein equation. E-Mail: [email protected] E-Mail: [email protected] E-Mail: [email protected] 1 Canonical quantum gravity has been initiated by DeWitt in the seminal paper [1]. As ...

We give a derivation of the loop equation for two-dimensional gravity from the KdV equations and the string equation of the one matrix model. We find that the loop equation is equivalent to an infinite set of linear constraints on the square root of the partition function satisfying the Virasoro algebra. We give an interpretation of these equations in topological gravity and discuss their exten...