National Public Radio: MICHELE NORRIS, host: From NPR News, this is ALL THINGS CONSIDERED. I’m Michele Norris. ROBERT SIEGEL, host: I’m Robert Siegel. And we begin this hour with what we hope will be the end. Twelve weeks after the Deepwater Horizon catastrophe, BP may be on the verge of shutting off the flow of oil into the Gulf of Mexico. An operation planned for today will be just a test, but if it works, the gusher could soon be over. Joining us with the latest is NPR science …