WASHINGTON - Parts of New Orleans are sinking far more rapidly than scientists first thought, more than an inch a year, new research suggests. That may explain some levee failures during Hurricane Katrina and raises more worries about the future. The research, being published Thursday in the journal Nature, is based on new satellite radar data for the three years before Katrina struck in 2005. The data show that some areas are sinking — from overdevelopment, drainage and natural seismic shifts — four or five times faster than the rest of the city. And that, experts say, can be deadly....