Scientific American (original name: Scientific American, abbreviation: Sci Am) is an American popular science magazine, started on August 28, 1845, at first published weekly, later changed to monthly; as the sister publication of Nature, Scientific American covers the audience including business owners, senior managers, decision makers and opinion As a sister publication of Nature, Scientific American covers business owners, senior managers, decision makers and opinion leaders, complementing the academic audience of Nature. To date, 151 Nobel laureates have contributed, and four of the 2009 issue's contributors have won Nobel Prizes.