A strengthening movement to bring economic pressure to bear in Sudan got a lift this week when Illinois became the first state to pass a bill aimed at forcing public pension funds to shed investments in companies with business ties in the African nation...Among the companies doing business in Sudan are Schlumberger...Alcatel...Siemens...Spokeswoman [from Siemens] Paula Davis said that the company has "a policy of constructive engagement" with Sudan and that its projects are "key components to improving living conditions."...Canada's Talisman Energy Inc. sold its oil and pipeline interests in Sudan in 2003...Gillette Co. said a small amount of its personal-care products is sold in Sudan through independent distributors, and Goodyear Tire & Rubber Co. said its farm tires are sold there. "If you were to buy a tire from us, you could sell it to anyone you want," Goodyear spokesman Keith Price said. "We don't have any ability to control third parties."...[Harvard University's] endowment agreed last month to sell its stake in PetroChina...[which has] operations in Sudan.