The emotional roller coaster captured on Twitter can predict the ups and downs of the stock market, a new study finds. Measuring how calm the Twitterverse is on a given day can predict the direction of changes to the Dow Jones

The iPad and iPhone have hogged the media’s attention for months, but Apple is preparing to turn the spotlight onto its Macintosh computers in a press conference Wednesday.

Just what can we expect? Apple observers are exchanging whispers about new notebooks and a preview of the next Mac operating system. Here’s a quick rundown of what Apple is likely to unveil at the