If a President dies in office does the Secretary of State automatically become acting President?

http://en.wikipedia.org/wiki/United_States_presidential_line_of_succession#Constitutional_foundation

" {| ! 1 | Vice President and President of the Senate Joe Biden ! 2 | Speaker of the House of Representatives Nancy Pelosi ! 3 | President pro tempore of the Senate Robert Byrd ! 4 | Secretary of State Hillary Rodham Clinton "

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