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Pearly mussels (Unionoidea) live in lakes, rivers, and streams around the world. These bivalves play important roles in freshwater ecosystems and were once both culturally and economically valuable as sources of food, pearls, and mother-of-pearl. Today, however, hundreds of species of these mussels are extinct or endangered. David L. Strayer provides a critical synthesis of the factors that control the distribution and abundance of pearly mussels. Using empirical analyses and models, he assesses the effects of dispersal, habitat quality, availability of fish hosts, adequate food, predators,...

This succinct book gives an intimate view of the day-to-day functioning of a remarkable river that has figured prominently in history and culturethe Hudson, a main artery connecting New York, America, and the world. Writing for a wide audience, David Strayer distills the large body of scientific information about the river into a non-technical overview of its ecology. Strayer describes the geography and geology of the Hudson and its basin, the properties of water and its movements in the river, water chemistry, and the river s plants and animals. He then takes a more detailed look at the...

l RNA tumor viruses have become increasingly utilized in studies of cellular transformation and gene regulation. The genes of retroviruses exist in two forms; as extrachromosomal, RNA-containing, infectious particles and as DNA pro 2 viruses stably associated with cell genes. Components from the extracellular form can be collected in large quantity and purified for the preparation of molec ular probes. These probes can be used to dissect the sequence of events required for the establishment and expression of the integrated form. Furthermore the 2 genomes of retroviruses originated from normal...