Fox News Channel rolls out a new weekday lineup today that boosts the profiles of anchors Martha MacCallum and Jane Skinner. Ms. MacCallum gets a new show, “Live Desk With Martha MacCallum,” with a split format that delivers the top stories of the day followed by a moderated discussion. Ms. Skinner gets her first permanent anchor assignment with “Fox News Live,” a bridge between Ms. McCallum at 1 p.m. and Shepard Smith at 3 p.m. Fox News has suffered some erosion among its 25- to 54-year-old audience, the news viewers most prized by advertisers. The network retains a Grand Canyon of a lead over second-place CNN in that age group and in total viewers. Fox News’s daytime strategy is “just trying to move the ball forward, especially with comments from Washington and elsewhere, getting ahead of the story,” said network executive producer for news Jay Wallace. “I think that’s the biggest challenge for everyone’s daytime.” Ms. MacCallum said her anchor desk differs from the one being used by “CBS Evening News” anchor Katie Couric. “It’s sit-around-able a la a dinner table.” Still, perching on a desk as Ms. Couric may be tempting, Ms. MacCallum said. “I’m not against it.”