We analyze the volatility surface vs. moneyness and time to expiration implied by MIBO options written on the MIB30, the most important Italian stock index. We specify and fit a number of models of the implied volatility surface and find that it has a rich and interesting structure that strongly departs from a constant volatility, Black-Scholes benchmark. This result is robust to alternative ec...

We consider a variant of the caching problem, where each request is a set of pages of a fixed size, instead of a single page. In order to serve such a request, we require at least one of those pages to be present in the cache. Each page is assumed to have unit size and unit cost for getting loaded into the cache. We prove lower bounds on the competitive ratio for this problem in both the determ...

The Indian gharial (Gavialis gangeticus) is not found in saltwater, but the geographical distribution of fossil relatives suggests a derivation from ancestors that lived in, or were at least able to withstand, saline conditions. Here, we describe a new Oligocene gharial, Aktiogavialis puertoricensis, from deltaic-coastal deposits of northern Puerto Rico. It is related to a clade of Neogene ghar...

—The taxonomy of calyptraeid gastropods is made difficult by their morphologically simple, plastic shells and the numerous instances of morphological convergence within the family. The small speckled species of Crepidula from the West Atlantic have all previously been referred to as C. convexa Say, 1822. Recent developmental and genetic work has shown that there are two species along the coast ...

On 12 August 2000 two explosions damaged the Russian submarine, the Kursk. The largest event was well recorded at seismic networks in northern Europe, which we then modeled. We developed a hybrid method based on generalized ray theory that treats an explosive source embedded in a fluid and recorded along continental paths. Matching record sections of observations with synthetics, we obtain an e...

The effects of five towns on river water pollution were examined along the Łyna River (southern watershed of the Baltic Sea, northern Poland). The relationships among the spatially derived indicators of urbanization, environmental variables, and physico-chemical and microbiological data (heterotrophic plate count at 22 and 37 °C, and fecal coli) obtained from longitudinal river profiling have b...

Due primarily to alteration ofriparian vegetation and nest parasitism by brown-headed cowbirds (Molothrus ater). the least Bell's vireo (Vireo bellii pusillus) has under­ gone a tremendous decline in range and numbers since the 1920's. In 1987. we sampled vegetation at 32 nest sites to characterize nesting habitat ofleast Bell's vireos in the Santa Ynez River drainage. Most next (59.4%) were lo...