Silicon Valley is world-renowned for the Nobel Prize winners and MacArthur "geniuses" behind theoretical breakthroughs in science, technology, engineering and math. Less well-known are people like Patrick Pickerell, a high school dropout whose $10 million-a-year Pleasanton metal manufacturing company is powered by people with no university credentials but plenty of math and fix-it skills -- ingredients essential to innovation. A new report, "The Hidden STEM Economy," reveals that a university degree is not required for 27.5 percent of all jobs in the San Jose area in the fields of science, technology, engineering and math. The number is even higher --...