This episode's headline: Likely Leader; Land Grab; Women in Science. ANCHOR: JIM LEHRER; GUESTS: LAITH KUBBA; JUAN COLE; JAN CRAWFORD GREENBURG; SANDRA WITELSON; VIRGINIA VALIAN; KIMBERLEE SHAUMAN;CORRESPONDENTS: KWAME HOLMAN; RAY SUAREZ; SPENCER MICHELS; MARGARET WARNER; GWEN IFILL; TERENCE SMITH; KWAME HOLMAN