SAN FRANCISCO — Google, which has been expanding far beyond its original business of Internet search advertising, is changing its operating structure by creating a new holding company called Alphabet.

The company said its new structure will give more independence to many of its wide-ranging projects.

Alphabet will be comprised of the core Google business — including Internet search, mapping and YouTube — along with newer businesses that will be managed separately, such as Google Fiber, Nest and the investment arm Google Ventures.

WASHINGTON — Air traffic controllers' work schedules often lead to chronic fatigue, making them less alert and endangering the safety of the country's air traffic system, according to a study the U.S. government has kept secret for nearly four years.Federal Aviation Administration officials have declined to furnish a copy of the report despite repeated requests and a Freedom of Information Act request by The Associated Press. However, the AP was able to obtain a draft of the final report dated Dec. 1, 2011.

NEW YORK — A revamped Diet Pepsi without aspartame is popping up on store shelves.PepsiCo said its new Diet Pepsi should be available nationally this week. In response to customer feedback, the company said earlier this year that it would replace the aspartame in the drink with another artificial sweetener that has less baggage.The rollout will test the theory that the sweetener is to blame for losing customers, or if other issues might be at play. Diet Coke still has aspartame.

WASHINGTON — The U.S. Postal Service on Monday reported a net loss of $586 million this spring, a big improvement for the cash-strapped agency compared to a nearly $2 billion loss during the same period last year.Postal officials said the loss was mitigated largely because interest rates, which are associated with worker' compensation expenses, swung in the agency's favor. Operating expenses outside the Postal Service's control dropped by $1.6 billion during the same period last year to $389 million this spring.The Postal Service is an independent agency that receives no tax dollars.

NEW YORK — Adobe is the latest tech company to extend its paid parental leave policy after Netflix said it would offer corporate employees up to a year of paid leave to care for new babies.Adobe said Monday that it will offer parents who are the primary caregivers 16 weeks of paid leave after the birth or adoption of a child. That's in addition to 10 weeks of paid medical leave following childbirth, so a new mother could take a total of 26 weeks off — up from the current nine weeks.