The first people to arrive in America traveled as at least two separate groups to arrive in their new home at about the same time, according to new genetic evidence published Current Biology.

Everyday, all over the world, people assemble peacefully into crowds at places such as shopping malls, sporting events, concerts and tourist sites--but crowds can shift from peaceful to unruly, even riotous, in just a few minutes given the right conditions.

The factors that cause a "charged" crowd to reach a "tipping point" and erupt into violence are not well understood by scientists because crowd behavior is so difficult to study. No one wants to incite a riot for the sake of science and surveys of individuals about their behavior as part of a crowd have not been that reliable.

On Monday, Jan. 5, NASA issued a request for proposal for the Ares V rocket that will perform heavy lift and cargo functions as part of the next generation of spacecraft that will return humans to the moon. The request is for Phase I concept definition and requirements development for the Ares V rocket. Proposals are due to NASA's Marshall Space Flight Center in Huntsville, Ala., no later than 1 p.m. CDT on Feb. 9. 

The lowest ever levels of oxygen in humans have been reported in climbers on an expedition led by UCL (University College London) doctors. The world-first measurements of blood oxygen levels in climbers near the top of Mount Everest, published in this week's New England Journal of Medicine (NEJM), could eventually help critical care doctors to re-evaluate treatment strategies in some long-term patients with similarly low levels of blood oxygen. 

Many objects in the universe emit radio waves. In 1931, American physicist Karl Jansky first detected radio static from our own Milky Way galaxy. Similar emission from other galaxies creates a background hiss of radio noise. 

Now a team led by Alan Kogut of NASA's Goddard Space Flight Center in Greenbelt, Md., today announced the discovery of cosmic radio noise that booms six times louder than expected.

The finding comes from a balloon-borne instrument named ARCADE, which stands for the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission. In July 2006, the instrument launched from NASA's Columbia Scientific Balloon Facility in Palestine, Texas, and flew to an altitude of 120,000 feet, where the atmosphere thins into the vacuum of space.

In popular legend, Lucrezia Borgia, Duchess of Ferrara (1480- 1519), stands falsely accused of poisoning her second husband. Victor Hugo portrayed her in thinly veiled fiction as a tragic femme fatale. Buffalo Bill named his gun after her.  

But new research by USC historian Diane Yvonne Ghirardo claims that the only sister of Machiavelli's Prince was less interested in political intrigue than in running a business, undertaking massive land development projects that "stand alone in the panorama of early sixteenth-century projects, not only those initiated by women," Ghirardo says.