Sometimes unexpected phone calls actually bear good news rather than dubious offers of free credit reports. Consider five MIT alumni who received such calls this fall: one learned he’d won a Nobel Prize, and four others found out they were among the 24 new MacArthur Fellows announced in September 2009.

The MacArthur honor, awarded annually by the John D. and Catherine T. ­MacArthur Foundation and popularly known as a “genius” grant, is worth $500,000 with no strings attached. The awardees were all cited for their “exceptional originality in and dedication to their creative pursuits.”

Esther Duflo, PhD ‘99, the Abdul Latif Jameel Professor of Poverty Alleviation and Development Economics at MIT, was chosen for her studies exploring new ways of reducing global poverty. Duflo has been a leader in developing randomized field experiments to assess what types of foreign aid and investment can produce sustainable long-term benefits. (For more details, see “Poverty’s Researcher,” p. M22.)

The foundation cited Peter Huybers, SM ‘02, PhD ‘04, an assistant professor of earth and planetary sciences at Harvard, for his climate studies. Huybers conducts research that helps explain changes in the size of the earth’s ice sheets over the last three million years, as well as fluctuations in temperature over the same period.

John A. Rogers, SM ‘92, PhD ‘95, a professor of engineering at the University of Illinois, was named a fellow for his work in materials science. Rogers is developing flexible semiconductors, based either on silicon or on carbon nanotubes, that could lead to new devices with signal-processing capabilities. Applications could range from medicine to clean energy to consumer goods.

Daniel Sigman, PhD ‘97, a biogeochemist at Princeton University, was given the award for research reconstructing the chemical history of the earth’s oceans. Sigman’s analysis of sedimentary deposits has helped illuminate the ways oceanic biomass has affected the climate over the past two million years.

In October, Oliver ­Williamson ‘55 won the Nobel Prize in economic sciences (sharing the honor with Elinor Ostrom of Indiana University). ­Williamson, a professor emeritus of business, economics, and law at the University of California, Berkeley, was cited for the work he has done to explain the role of corporations within free markets. He published influential papers outlining how corporations help the marketplace function by allowing complicated transactions to take place more efficiently.