Purpose At the beginning of the production year producers face a complex risk management decision environment given by risks specific to their operation, multiple crop insurance contracts and hedging opportunities. The purpose of this paper is to provide a producer-level framework for risk management decision making, focusing on the interaction between crop insurance and hedging. Design/methodology/approach The authors develop a Monte Carlo simulation model that generates a producer’s net income (NI) distribution that incorporates historical producer risk, price-yield correlation via a copula, price risk, and production costs. The authors evaluate the NI distribution through a modified Modern Portfolio Theory (MPT) decision framework. The authors use the modified MPT decision framework to explore tradeoffs between expected NI and farm ruin (defined as 1 or 5 percent expected shortfall) from different crop insurance contracts and pre-harvest hedging options. Findings Only revenue protection and the highest two levels of coverage level exist on the efficient frontier. The level of hedging on the efficient frontier ranges from 0 to 55 percent of Actual Production History. The authors find that increasing coverage level 5 percent (from 80 to 85 percent) negatively impacts the optimal hedging amount by 26 percentage points (from 35 to 9 percent). Originality/value The model provides the precise identification of financial benefits from different risk management strategies by incorporating producer-level historical yield data, using a copula to capture yield-price dependency structure and producer production cost in generating the NI distribution. This model can be applied to any producer’s characteristics and data.

Study of detonation-wave phenomena in high explosives is a necessary adjunct to the understanding of explosive effects and their practical applications. The phenomena associated with a single detonation wave are complex; the collision of several may be spectacular. The sequence of ultra-high speed photographs on the front cover of this issue of Science shows the collision of eight waves. These photographs, made by the Naval Weapons Laboratory, Dahlgren, Virginia, are a by-product of a general study of initiation, propagation, and interaction of detonation waves undertaken as an aid to explosive system design. The action which occurs in just a few microseconds shows a symmetry in the detonating explosive which rivals that of the snowflake. When photographed in color, the growth and fading of this rather strange explosive "snowflake" give an appearance of unreal beauty.These photographs were made with a Beckman and Whitley model 189 framing camera operating at about 600,000 frames per second, with individual exposure times of about 0.6 microsecond. A disk of DuPont EL 506C sheet explosive 25.4 centimeters in diameter by 0.379 centimeter thick was mounted on plywood. The explosive was initiated simultaneously at eight equidistant points on its rear surface with exploding bridge-wire detonators.A frame-by-frame description (beginning with the upper left-hand corner and reading downward) follows: 1) A still shot of the disk mounted on plywood.2-3) Detonation begins simultaneously and expands uniformly. 4-9) Extreme pressures at the collision of wave fronts produce lines of intense luminosity resulting from the ionization of the air. 10) Collision lines reach the center. 11-15) Reflected shock waves pro- DECEMBER 1964 Detonation-Wave PhenomenaStudy of detonation-wave phenomena in high explosives is a necessary adjunct to the understanding of explosive effects and their practical applications. The phenomena associated with a single detonation wave are complex; the collision of several may be spectacular. The sequence of ultra-high speed photographs on the front cover of this issue of Science shows the collision of eight waves. These photographs, made by the Naval Weapons Laboratory, Dahlgren, Virginia, are a by-product of a general study of initiation, propagation, and interaction of detonation waves undertaken as an aid to explosive system design. The action which occurs in just a few microseconds shows a symmetry in the detonating explosive which rivals that of the snowflake. When photographed in color, the growth and fading of this rather strange explosive "snowflake" give an appearance of unreal beauty.These photographs were made with a Beckman and Whitley model 189 framing camera operating at about 600,000 frames per second, with individual exposure times of about 0.6 microsecond. A disk of DuPont EL 506C sheet explosive 25.4 centimeters in diameter by 0.379 centimeter thick was mounted on plywood. The explosive was initiated simultaneously at eight equidistant points on its rear surface with exploding bridge-wire ...

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