Bernie Sanders scored a decisive victory in the Democratic presidential caucuses in Nevada, while Joe Biden appeared headed to a second-place finish that would give his struggling campaign new hope.Sanders, a senator from Vermont, had 45 percent of the county convention delegates in Nevada with about 4 percent of the precincts reported, and television networks predicted he would cruise to an easy win.But there were long delays getting more results reported, more than five hours after the caucuses started.