With 13 days left until the Nov. 6 election, President Obama and his Republican challenger, Mitt Romney, both included trips to Iowa and Nevada on their schedules. Each tried to fire up his supporters and cast doubts about the other to gain an advantage in a race that appears essentially tied.

At rallies in Davenport, Iowa, and Denver, both swing states where the election is fluid, Obama trotted out attack lines he's used in recent days against the former Massachusetts governor.

We almost brought you news today about a study that appeared to raise some troubling questions about aspartame, the popular sugar substitute found in many common foods like diet soda. Note the key word — almost.

A study due to be published at 3 p.m. Wednesday in the American Journal of Clinical Nutrition and released to reporters earlier in the week under embargo found some correlation between drinking diet soda and an increased risk of leukemia and Non-Hodgkin's lymphoma, as well as a few other rare blood-related cancers.

In a number of swing states, early voting means many people are already casting their ballots. Typically, that entails voting by mail or visiting a county elections office.

But in Iowa, satellite voting — where "pop-up" polling stations allow people to vote at convenient times and nontraditional locations — is growing in popularity.

There is a remarkable change going on in Mogadishu, Somalia — often dubbed the world's most dangerous city. For starters, it may not deserve that title anymore.

Last year, African Union forces drove the Islamist militant group al-Shabab out of Mogadishu. Now, Somalia has a new president and prime minister who have replaced the corrupt and unpopular transitional government.

Hope is edging aside despair, and Mogadishu is coming back to life.