1:40 pm Pacific Time | The rally at the University of California at Berkeley, estimated at more than a thousand participants, has culminated in a sit-in at the main reading room in Berkeley’s Doe Library. As many as six hundred students are said to be sitting in at Doe at this hour, and university police have shut the doors to the room to prevent more from entering.

2:00 pm | Photos from the Berkeley action are up at Occupy CA.

2:40 pm | Reports on Twitter now suggest that the doors to the reading room have been opened, and additional students are being allowed in.

3:00 pm | Occupy CA reports that Doe Library is scheduled to remain open until 9 pm tonight. Librarians have told students they’re “welcome to stay” until then.

3:35 pm | A general meeting of the Doe sit-in folks has been called for four o’clock. Before the sit-in began, activists presented administrators with a list of demands and a 5 pm deadline.

3:50 pm | The Berkeley Daily Cal (which has been liveblogging today’s events admirably) has posted the list of demands that were presented to Berkeley administration earlier today. The list of twenty-two demands emphasizes campus and state budget issues.

4:35 pm | Today’s sit-in marks the first major student protest action of the new year in the UC system, and it comes at a time when Berkeley’s handling of previous demonstrations is facing heavy scrutiny. Judicial proceedings against participants in last year’s campus protests continue to drag on this fall, amid charges of administrative heavy-handedness and due process violations.

Will Berkeley pursue a new approach to student protest in the new year? Tonight might be the night we find out.

4:50 pm | Berkeley administrators have distributed a letter to the students sitting in. Here’s the text as provided by the Daily Cal:

To those protesting today for public higher education, we want to acknowledge the concerns that you have expressed to preserve public education in California and make the opportunity of education fairly available to every qualified student. As you know, this goal is shared by the entire UC Berkeley community. We take great pride in the fact that this year we have the largest number of low income undergraduate students in UC Berkeley’s history with the lowest net cost in recent history. Although we cannot respond to all of the demands for which you are fighting, we do support the cause of continuing to raise your voices to inform the California public of the need to continue to invest in public higher education. The ability to provide excellent education that is accessible and affordable is in the interest of all of the people in the State of California and is fundamental to the mission of the University of California, Berkeley.

“We want to acknowledge the concerns … this goal is shared … we do support the cause of continuing to raise your voices.” That doesn’t much sound like an administration that’s planning to send in the cops in four hours and ten minutes, does it?

6:30 pm | The Daily Cal reports on Twitter that about a hundred demonstrators remain, and that they have voted to occupy the room “indefinitely.”

Friday morning | The sit-in broke up around seven o’clock or a little earlier. Neither the Occupy CA liveblog, the Daily Cal liveblog, nor the Daily Cal morning story say exactly why, but a Cal editorial suggests that logistical problems played a role: “With impossible acoustics in the library’s North Reading Room, nobody could effectively communicate to the group. The decision to leave the room and go downstairs, one that some protesters realized only after reading The Daily Californian’s update, ended the occupation when participants decided to disperse.”

I should also note, I guess, that yesterday’s 4:50 pm update wasn’t intended to suggest that the Berkeley administration was extending an honest hand to the protesters, or inclined to negotiate in good faith. I interpreted their letter as a tactical move, intended — clumsily — to co-opt the occupation. But in terms of public relations, it’s dangerous to praise people’s ethics one moment and then arrest them the next.