STOCKHOLM, Sweden (AP) — Americans Leonid Hurwicz, Eric S. Maskin and Roger B. Myerson won the Nobel prize in economics on Monday for developing a theory that helps explain situations in which markets work and others in which they don't.

The three researchers "laid the foundations of mechanism design theory," which plays a central role in contemporary economics and political science, the Royal Swedish Academy of Sciences said.

The academy said their research helped explain decision-making procedures involved in economic transactions including, for example, what insurance policies will provide the best coverage without inviting misuse.

STOCKHOLM, Sweden (AP) — Two American scientists and a Briton won the 2007 Nobel Prize in medicine on Monday for groundbreaking discoveries that led to a powerful technique for manipulating mouse genes.

The widely used process has helped scientists use mice to study heart disease, diabetes, cancer, cystic fibrosis and other diseases.

The prize is shared by Mario R. Capecchi, 70, of the University of Utah in Salt Lake City; Oliver Smithies, 82, a native of Britain now at University of North Carolina in Chapel Hill, and Sir Martin J. Evans, 66, of Cardiff University in Wales.