Breaking down this week's Associated Press college basketball poll:
RAISING ARIZONA: Arizona is No. 1 in The Associated Press college basketball poll for the first time without Lute Olson as coach.
This is the sixth season in which the Wildcats have reached No. 1. The first time was a six-week stint in 1987-88, and the Wildcats went to reach the Final Four for the first time.
Arizona also made it to No. 1 in 1988-89, 1997-98, 2000-01 and 2002-03, spending 29 weeks in all on top of the poll. The longest run of those appearances at the top was 13 weeks in 2002-03, a season in which the Wildcats were never ranked below fourth and finished No. 2 in the final poll with a 28-4 record.
This will be coach Sean Miller's first time with a No. 1 team, although his teams at Xavier did rank in the top 10.
The Musketeers were ranked in three of Miller's five seasons at Xavier, and they reached the top 10 in 2007-08 and 2008-09. The highest ranking Miller managed at Xavier was seventh early in 2008-09, his last season there before taking over at Arizona.
OFF THE TOP: Michigan State's run at No. 1 ended at three weeks, the Spartans' longest stint on top of the poll.
The other two times Michigan State reached No. 1 - 1978-79 and 2000-01 - it was up there for two weeks.
THEY'RE BACK: North Carolina spent a week out of the poll. The Tar Heels continued their up-and-down early season by beating then-No. 1 Michigan State 79-65 on the road last week, knocking the Spartans from the top of the poll and earning their way back in at No. 18.
The Tar Heels were 12th in the preseason poll and fell to No. 24 after losing to Belmont at home. A neutral-court win over then-No. 3 Louisville moved them up to No. 16, but a loss to UAB had them out of the poll. The victory over Michigan State has them back in.
The other newcomers this week are No. 21 Colorado and No. 24 Missouri. Both were ranked last season - Colorado for two weeks and the Tigers for all but six weeks.
North Carolina's victory over Michigan State extended the Tar Heels' record for knocking off No. 1s.
The win was North Carolina's 13th over a top-ranked team, three more than runners-up Maryland and UCLA.
QUICK RUN: Dayton's first Top 25 appearance in four years lasted one week. The Flyers beat Delaware State 56-46 and lost at Illinois State 81-75 last week. Dayton's other loss was to No. 14 Baylor at the Maui Invitational.
ALSO GONE: The other two teams to fall from the poll this week had been ranked all season.
UCLA, which fell to 8-1 with the 80-71 loss to Missouri, was No. 22 in the preseason poll and reached as high as 18th, its ranking before falling out.
Michigan, which was No. 7 in the preseason poll, fell out from 22nd with its third defeat of the season. The Wolverines lost 79-69 at Duke last week. Their other losses were 77-70 to Iowa State and 63-61 to Charlotte.
The Wolverines were ranked for the last 44 weeks, a streak started with the preseason poll of 2011-12, the sixth-longest current streak. Duke has the longest current streak, 122 weeks starting with the preseason poll of 2007-08.
DOUBLE-RANKED GAMES: There will be three games this week between ranked teams.
On Tuesday, No. 13 Kansas is at No. 19 Florida. On Friday, it's an instate battle when No. 23 Iowa visits No. 17 Iowa State. On Saturday, No. 11 Kentucky is at No. 18 North Carolina.
LEAGUE LOOK: With Michigan falling out of the Top 25, the Big Ten lost its lead among the conferences in ranked teams.
The Big Ten is now tied with the Big 12 with four teams each in the rankings. The Pac-12, which lost UCLA but gained Colorado; the American Athletic Conference; the Atlantic Coast Conference; and the Southeastern Conference, which added Missouri this week, are tied with three teams each.