Undated (AP) _ Nearly 200 students rallied at Yale University on Tuesday to call for the university to withdraw investments in companies doing business in South Africa.Yale's administration, which says it closely watches its investments in such companies, rejected the protesters' calls for a public debate.

Sit-ins by students opposed to university investments in companies with South African operations continued at UCLA and Rutgers, and a similar protest against state investments was in its seventh day at the Wisconsin state capitol.

After the rally at Yale, about 40 students began what was billed as a 24- hour vigil outside the offices of the university administration.

''Until apartheid is fully dismantled, we will not accept Yale's talk of gradual reform and peaceful change,'' Samantha Sparks, a member of a Yale student group called the Coalition Against Apartheid, told the rally.

However, university spokesman Walter Littell said Yale's administration rejected the coalitions proposal for a public debate as inappropriate and unproductive.

Littell said that if corporations fail to comply with the Sullivan Principles - which demand equal wages and opportunities for all employees of participatings U.S. firms in South Africa - the university administration considers a range of actions that includes divestment.

Last fall, Yale divested from three companies for that reason.

The Wisconsin demonstrators are seeking the withdrawal of state retirement fund investments in companies operating in South Africa.

Gov. Anthony Earl, who supports the bill sought by the students, has pledged to appoint two persons to the state Investment Board who oppose apartheid, South Africa's rigid system of segregation.

About 20 anti-apartheid protesters were camped out Tuesday at UCLA, where a tent city was set up on Sunday, university spokeswoman Darlene Skeels said.

The protest has been peaceful and university officials have not decided how long to permit the tents to remain, she said.

Rutgers students, in their 19th day of an anti-apartheid sit-in at the student center in New Brunswick, N.J., on Tuesday requested that the school's board of governors and board of trustees meet jointly on May 10 to vote on a total divestment policy.

Rutgers spokeswoman Judy Davis said no decision has been made about the students' request.

On Feb. 8, the board of trustees approved a ''selective divestiture'' policy. Rutgers sold $3.67 million worth of investments in seven firms doing business in South Africa.

Holly Glaser of the Rutgers Coalition for Total Divestment Glaser said the protest has been drawing a ''pretty good core of about 100 people who are very committed and sleep here. But as it is finals time the numbers do dwindle during the day.''