A simulation model for evaluating a set of emergency vehicle base locations: development, validation, and usage.

This paper describes our experiences in developing a simulation model for evaluating a set of emergency response vehicle base locations. The project was undertaken jointly by the University of Arizona and the Tucson Fire Department. The issues of model development, data collection, model validation, and experimentation are discussed. The critical nature of the problem and the clients' lack of experience with mathematical models, made model validation the major step in gaining user acceptance. We show that looking solely at standard performance statistics such as the calls successfully serviced, may lead to the acceptance of an invalid model. We also show that the high level of detail used in many simulation models for evaluating base locations is unnecessary in the current case. An analysis evaluating two alternative sets of locations for the Tucson system is discussed.     

Bondholder Wealth Effects in Mergers and Acquisitions: New Evidence from the 1980s and 1990s

We examine the wealth effects of mergers and acquisitions on target and acquiring firm bondholders in the 1980s and 1990s. Consistent with a coinsurance effect, below investment grade target bonds earn significantly positive announcement period returns. By contrast, acquiring firm bonds earn negative announcement period returns. Additionally, target bonds have significantly larger returns when the target's rating is below the acquirer's, when the combination is anticipated to decrease target risk or leverage, and when the target's maturity is shorter than the acquirer's. Finally, we find that target and acquirer announcement period bond returns are significantly larger in the 1990s.