2014/04/15 Headlines: Ukraine Says Anti-Separatist Operation Underway; U.S. Threatens New Sanctions on Russia; Nigeria Bus Bomb Toll Jumps to 71, 124 Wounded; Ex-Klan Member Charged With Hate Crimes in Kansas Jewish Center Shootings; Federal Agents Cede to Anti-Gov't Nevada Rancher After Armed Standoff; Army General Denies Chelsea Manning Clemency Bid; 9/11 Trial Suspended After Attorneys Claim Gov't Infiltration, Monitoring; Justice Dept. Won't Contest Ruling Clear Force-Feeding Challenges by Guantánamo Prisoners; Nebraska Landowners, Activists Unveil Anti-Keystone XL Crop Art; Report: Killings of Environmental Activists Surge Worldwide; Guardian US, Washington Post Win Pulitzer for NSA Reporting