Quantifying information transfer and mediation along causal pathways in complex systems

Measures of information transfer have become a popular approach to analyze interactions in complex systems such as the Earth or the human brain from measured time series. Recent work has focused on causal definitions of information transfer aimed at decompositions of predictive information about a target variable, while excluding effects of common drivers and indirect influences. While common drivers clearly constitute a spurious causality, the aim of the present article is to develop measures quantifying different notions of the strength of information transfer along indirect causal paths, based on first reconstructing the multivariate causal network. Another class of novel measures quantifies to what extent different intermediate processes on causal paths contribute to an interaction mechanism to determine pathways of causal information transfer. The proposed framework complements predictive decomposition schemes by focusing more on the interaction mechanism between multiple processes. A rigorous mathematical framework allows for a clear information-theoretic interpretation that can also be related to the underlying dynamics as proven for certain classes of processes. Generally, however, estimates of information transfer remain hard to interpret for nonlinearly intertwined complex systems. But if experiments or mathematical models are not available, then measuring pathways of information transfer within the causal dependency structure allows at least for an abstraction of the dynamics. The measures are illustrated on a climatological example to disentangle pathways of atmospheric flow over Europe

HOW TO PAY FOR AGRICULTURAL INCOME SUPPORTS

This paper examines the impact of deficit reductions on agricultural price support spending, and proposes several policy innovations designed to remove agricultural programs from the entitlement category. First, agricultural program costs are analyzed in relation to deficit reduction requirements resulting from recent legislation. Second, price support and food stamp programs are proposed as a separate budget category to be financed through an excise tax on retail food sales. Third, the incidence of this tax on consumers is considered, and compensation for lower income groups is proposed via expanded eligibility for the food stamp program. A final section presents some conclusions for policy.Agricultural and Food Policy, Agricultural Finance,

ECONOMIC IMPLICATIONS OF WIDER COMPENSATION FOR "TAKINGS." OR, WHAT IF AGRICULTURAL POLICIES RULED THE WORLD?

Agricultural and Food Policy,

International Public Goods, Export Subsidies, and the Harmonization of Environmental Regulations

Environmental Economics and Policy, International Relations/Trade,

AN ASSESSMENT OF U.S. AGRICULTURAL POLICY AND LINKAGES TO TRADE AND ENVIRONMENTAL ISSUES

Agricultural and Food Policy,

Minnesota Agriculture in the New Millenium

Minnesota is by any standard one of the leading agricultural places in the United States, both in terms of farm production and as a headquarters for some of the largest agrifood and agronomic enterprises in the world. Several factors are likely to affect the future of Minnesota agriculture in the 21st century. First, the state is likely to remain a center of agribusiness activity, and is emerging as a leader in the development of new technologies based in genomics and renewable fuels. Second, Minnesota agriculture will remain highly dependent on global markets, and thus has a major stake in world trade. Third, domestic farm and fiscal policies will determine the extent to which the state continues to receive federal payments to farmers, who also depend on the overall health of the economy. Finally, the rising cost of fossil-fuel based energy has major implications for Minnesota farmers costs for fuel, fertilizer and transport. Together, these four factors describe an environment that will challenge Minnesota agriculture in the years to come.Agricultural and Food Policy,

Conceptual design study Science and Application Space Platform SASP. Volume 1: Executive summary

The system design philosphy applied in the development of this platform concept is summarized. The system is to provide for simple, low cost, initial capability of accommodating Spacelab payloads that are modified for long duration flight. The supporting research and technology are also summarized

PROSPECTS FOR THE URUGUAY ROUND IN AGRICULTURE

International Relations/Trade,

AGRICULTURAL TRADE IN THE URUGUAY ROUND: INTO FINAL BATTLE

International Relations/Trade,