Many leaders in business, government and education warn that a shortage of scientists is jeopardizing the nation's world leadership in science and technology, along with its military supremacy and high standard of living. For a short-term fix, they propose loosening immigration restrictions to allow more high-skilled workers from overseas. Long term, they say the United States must greatly improve pre-college education, produce more college graduates with mathematics and science degrees and increase investment in research and development. Others argue the alarm is just a scare tactic by employers who want to import more high-tech workers and pay them low wages. Across the country, meanwhile, businesses are joining thousands of schools in innovative efforts to convince more children to study science and to teach them more effectively.