New York Times: After decades of increasingly dire warnings, countless studies and countermeasures, scientists are beginning to mull over hints of something that few of them wish to contemplate: The despised Asian carp may have finally arrived in the Great Lakes. “May have” are the operative words. The latest hint consists of a single water sample, one of scores taken last May from Lake Michigan, that tested positive for remnants of DNA from one particularly destructive species, silver carp. Experts debate the…