5. New studies of the climate confirmed the long held suspicion that man-made activities have contributed to the warming of the climate. Yet at an international meeting to devise ways of reducing industrial emission of waste gases, delegates failed to agree on common action.
6. After 4 flat years, cases of mad cow disease resumed their increase in Britain, dashing hopes that the incipient epidemic had peaked. An untreatable infection that turns the brain to mush, mad cow disease is contracted by eating diseased beef.
7. The first inhabitants arrived at the International Space Station and a few weeks later a second space shuttle delivered solar panels with which to power it.
8. Physicists at the European particle accelerator believed they had captured the first experimental evidence for the existence of the Higgs boson, a predicted subatomic particle which occupies a central place in the leading theory of matter.
9. Stem cells, the special cells used by the body to repair and maintain its own tissues, are coming to the fore as a possible medical treatment for many degenerative diseases of aging. Among many advances in understanding stem cells, biologists showed how they could be used to repair damage to the brains of rats, enabling paralyzed animals to move again.
The concept of regenerative medicine suggests that a new kind of medicine, based on stem cells and cell signaling factors, could be developed. Its goal would be not just to patch up damaged tissues but to replace and rejuvenate them.
10. Archeologists and population geneticists are on the verge of a grand synthesis that will document the history of the past 50,000 years, at least in terms of the migrations by which humans left Africa and populated the rest of the world. Drawing on new data derived by analyzing mutations in the Y chromosome, geneticists have reconstructed the migrations that first brought people into Europe between 45,000 and 20,000 years ago.
• What We All Spoke When the World Was Young (February 1, 2000 NYTimes)
• On Road to Human Genome, a Milestone in the Fruit Fly (March 24, 2000 NYTimes)
• First Complete Plant Genetic Sequence Is Determined (December 14, 2000 NYTimes)
• Genetic Code of Human Life Is Cracked by Scientists (June 27, 2000 NYTimes)
• Deaths Tied to Mad Cow Disease on the Rise (July 25, 2000 NYTimes)
• On a Particle's Trail, Physicists Seek Time (November 4, 2000 NYTimes)
• In Early Experiments, Cells Repair Damaged Brains (November 7, 2000 NYTimes)
• Teaching the Body to Heal Itself (November 7, 2000 NYTimes)
• Scientists Rough Out Humanity's 50,000-Year-Old Story (November 14, 2000 NYTimes)