This is the same Kuiper object as on the other threads.
If that's true then the NYT must have . . . screwed up. (Inconceivable!) The earlier announcements said that it is definitely smaller than Pluto. But the NYT says it's definitely larger. . . gee, whom to believe, whom to believe. . .?
Three massive new Kuiper belt objects have been cataloged in the last day or so, two in the ballpark of the size of Pluto, and one unambiguously larger. The amateur Spanish astronomer scooped Brown on that other object, and so Brown's group is publishing the rest of their objects, lest they lose credit for those as well.
This one, 2003 UB313, is by far the most interesting as it is more like a regular planet in many respects. Unlike the other objects and Pluto, it does not have the Neptunian orbital resonance thing going on.