WASHINGTON (AP) - President Barack Obama will launch an administration-wide effort Wednesday to create new policies aimed at preventing another mass school shooting.  Obama is tasking Vice President Joe Biden with spearheading the process, which is a response to Friday's deadly attack at a Connecticut elementary school. The president will announce the effort from the White House.  White House aides say the president is not expected to announce any major policy decisions Wednesday. But the initiative underscores the political urgency the White House feels in the wake of the shooting.  Obama aides say Obama is likely to pursue some tightening of gun laws, including a ban on assault-style weapons. He is also likely to seek ways to improve mental health resources and school safety.