New York--Gruner + Jahr USA Publishing has shaken up the staff at its recently created business unit. The company said Thursday that Inc. publisher Gary Mirkin will replace Fast Company's Julian Lowin, who has resigned. Mirkin will be replaced by Lee Jones, formerly publisher of Ziff Davis Media Inc.'s Smart Business for the New Economy. Jones was also previously publisher of Entrepreneur, the small business title Gruner + Jahr has been rumored to be interested in purchasing. Former The Industry Standard publisher Steve Thompson will join Gruner + Jahr in the newly created position of VP-western region, business information group.