Trade flows and the international business cycle

We investigate into the role of the trade channel as important determinant of a country's current account position and the degree of business cycle synchronization with the rest of the world by comparing the predictions of two types of DGE models. It is shown that the behavior of a country's external balance and the international transmission of shocks depends amongst other things on two factors: i) the magnitude of trade interdependence, ii) the degree of substitutability between importable and domestically-produced goods. Using time series data on bilateral trade flows, we estimate the magnitude of trade interdependence and the elasticity of substitution between importable and domestic goods for the G7 countries. Given these estimates, idiosyncratic supply shocks potentially induce changes in the current account and foreign output that vary in direction and magnitude across G7 countries. The relationship between the magnitude of foreign trade and the import substitutability with various correlation measures is examined empirically in a cross-sectional dimension. First Draft, July 2001. Final Draft, November 2001. Klassifikation: E32, F4

Country-specific and global shocks in the business cycle

Industrial production in G7 countries is assumed to be driven by two exogenous disturbances. Those disturbances are identified in a VAR model so they can be interpreted as country-specific and global supply shocks. The dynamic properties of the model are analyzed and the relative importance of each shock is measured. It is shown that the VAR model matches most of the theoretical predictions of standard intertemporal open-economy models. The identified structural disturbances are analyzed with regard to their impact on the current account and investment. First Draft, October 2000. Final Draft, January 2001. This paper is based on the second chapter of my doctoral dissertation at the University of Frankfurt. Klassifikation: E32, F4

A House Divided: The Development of the Ideological Divide of American Jewry and its Influence on the American Response to Nazi Germany 1933-1943

This thesis examines the response from the different American Jewish groups during Hitler’s rise to power and the subsequent Holocaust, and how the ideological divide that formed between Zionists and non-Zionists ultimately shaped the ultimately limited their ability to exert political influence toward policies to aid European Jewry. The main groups that were analyzed were the American Jewish Committee, the Joint Distribution Committee, B’nai B’rith, the American Jewish Congress, the World Jewish Congress, and the Zionist Organization of America. For purposes of analysis and clarity, the groups can be divided along the lines of extreme Zionist, which included the two Congresses and the Zionist Organization of America, and moderate to non-Zionists, which included the American Jewish Committee, the Joint Distribution Committee, and B’nai B’rith. At the core of their debate was how to respond to the growing anti-Semitic threat in Germany. The extreme Zionists were concerned with the goal of a Jewish homeland in Palestine and would not divert funds or resources from that goal, while the moderate to non-Zionists were concerned with the more immediate and pressing issue of the destruction of European Jewry. Factors that exacerbated these divides were issues such as anti-Semitism sentiments in the United States, skepticism about reports indicating the scale and scope of Nazi oppression of the Jews, and a Federal Government that believed in an Isolationist approach. What is abundantly clear is that this fundamental divide shaped the overall lack of political mobilization. What was constant was a state of paralysis or ineffective leadership during three seminal moments. Hitler’s appointment to Chancellor of Germany in January of 1933, with his anti-Semitic beliefs and doctrines, was met with some concern but generally dismissed by Jewish and political leaders in the United States. Kristallnacht, the economic destruction of German Jewry on November 9 and 10th, 1938, served as a wakeup call to many in the United States, and helped shed light on the grave situation faced by Jewish refugees, as well as created a sense of urgency amongst Zionists for the establishment of a homeland. News of the Final Solution, that was initially found out in August of 1942, left many Jews in a state of helplessness, as Zionists attempted to further bolster their case for Palestine, while moderate Zionists and non Zionists were paralyzed in terms of what could be done

Optical transparency of graphene as determined by the fine-structure constant

The observed 97.7% optical transparency of graphene has been linked to the value 1/137 of the fine structure constant, by using results for noninteracting Dirac fermions. The agreement in three significant figures requires an explanation for the apparent unimportance of the Coulomb interaction. Using arguments based on Ward identities, the leading corrections to the optical conductivity due to the Coulomb interactions are correctly computed (resolving a subtle theoretical issue) and shown to amount to only 1-2%, corresponding to 0.03-0.04% in the transparency.Comment: 5 pages, 2 figures, Minor changes, published version with a new titl

Master stability functions reveal diffusion-driven pattern formation in networks

We study diffusion-driven pattern-formation in networks of networks, a class of multilayer systems, where different layers have the same topology, but different internal dynamics. Agents are assumed to disperse within a layer by undergoing random walks, while they can be created or destroyed by reactions between or within a layer. We show that the stability of homogeneous steady states can be analyzed with a master stability function approach that reveals a deep analogy between pattern formation in networks and pattern formation in continuous space.For illustration we consider a generalized model of ecological meta-foodwebs. This fairly complex model describes the dispersal of many different species across a region consisting of a network of individual habitats while subject to realistic, nonlinear predator-prey interactions. In this example the method reveals the intricate dependence of the dynamics on the spatial structure. The ability of the proposed approach to deal with this fairly complex system highlights it as a promising tool for ecology and other applications.Comment: 20 pages, 5 figures, to appear in Phys. Rev. E (2018