Over the last years, active contour methods have become a basic tool in computer vision. They have proven to be efficient for various image processing applications, like reconstruction of the edges inside images or the tracing of image features. However, when applying the basic snake technique to synthetic aperture radar (SAR) remote sensing images, the reconstruction of edges may not be satisf...

Abundance and diet of larger predatory fishes in Phragmitesmarsh creeks were compared with those in natural Spartina alterniflora marshes and Phragmites marshes exposed to herbicides and burning (treated marshes). The most abundant fishes (n=3,107) caught in gill nets from June to November 2001 and May to November 2002 were Morone americana (white perch; 82%) and Ictalurus punctatus (channel ca...

The scyphomedusa Chrysaora quinquecirrha and lobate ctenophore Mnemiopsis leidyi are dominant consumers in the planktivorous food web in Chesapeake Bay, USA, and are important predators throughout much of their ranges. Our studies in the Patuxent River (a subestuary of Chesapeake Bay) and its tributary creeks suggest successive waves of population spread and trophic influence of these 2 gelatin...

Invasive species are a concern worldwide as they can displace native species, reduce biodiversity, and disrupt ecological processes. European bird cherry (Prunus padus) (EBC) is an invasive ornamental tree that is rapidly spreading and possibly displacing native trees along streams in parts of urban Alaska. The objectives of this study were to: 1) map the current distribution of EBC along two A...

Escherichia coli are widely used as indicators of fecal contamination, and in some cases to identify host sources of fecal contamination in surface water. Prevalence, genetic diversity and antimicrobial susceptibility were determined for 600 generic E. coli isolates obtained from surface water and sediment from creeks and channels along the middle Santa Ana River (MSAR) watershed of southern Ca...

Cattle and other livestock excrete endogenous steroid hormones, including estrogens, androgens, and progestins; therefore, allowing grazing livestock direct access to surface waters can result in the release of steroids in agricultural watersheds. Elevated concentrations of steroids are problematic because low concentrations of certain steroids can affect fish reproduction. To assess the occurr...

Amazon watersheds are a complex ecosystem: the interaction between terrestrial and aquatic ecosystems and the water level fluctuations are the main forcing function that regulates the biodiversity, the evolutionary processes and the interaction between terrestrial and aquatic biota in the large internal deltas, the extensive floodplains regions and the network of channels, creeks, rivers, meand...