ScienceDaily: Many people compost their food scraps and yard waste because they think it's the right thing to do. A new University of Washington study confirms that sentiment, and also calculates the environmental benefits associated with keeping these organic materials out of landfills. The biggest takeaway for residents of Seattle, San Francisco and other places that offer curbside compost pickup is to take advantage of that service -- and pat yourself on the back for using it. "You should definitely pay...