By Mary Williams Walsh Source: The New York Times The search for high returns takes many pension funds far and wide, but the Pennsylvania teachers’ fund went farther than most. It invested in trailer park chains, pistachio farms, pay phone systems for prison inmates — and, in a particularly bizarre twist, loans to Kurds trying to carve out their own homeland in northern Iraq. Now the F.B.I. is on the case, investigating investment practices at the Pennsylvania Public School [...]