How old are most species of North American birds? A longstanding debate centers on whether Pleistocene events caused substantial avian diversification. Two new syntheses of speciation times by Johnson and Cicero, and Weir and Schluter provide compelling evidence of recent Pleistocene speciation, whereas diversification rate analyses by Zink et al. suggest that most speciation events occurred ea...

We use simulations to study how the diversification of electricity generation portfolios influences wholesale prices. We find that the relationship between technological diversification and market prices is mediated by the supply to demand ratio. In each demand case there is a threshold where pivotal dynamics change. Pivotal dynamics preand post-threshold are the cause of non-linearities in the...

While explicitly assuming that stock price conveys valuable information to the management, we show that the value loss from diversification is a function of the stock price informativeness. More informed stock trading leads to a more efficient investment and a smaller diversification discount. © 2007 Elsevier B.V. All rights reserved.

In this paper we describe mechanisms for the management of secret keys, used in the securization of financial applications. The mechanisms Dynamic Key Handling and Reversed Dynamic Key Handling can be seen as particular methods to diversify keys in time, compatible with the present diversification by terminal and/or electronic purse.

A PROPORTIONALITY-BASED APPROACH TO SEARCH RESULT DIVERSIFICATION