Wednesday, June 28, 2006
tropical stonehenge
SAO PAULO, Brazil - A grouping of granite blocks along a grassy Amazon hilltop may be the vestiges of a centuries-old astronomical observatory — a find that archaeologists say shows early rainforest inhabitants were more sophisticated than previously believed.
The 127 blocks, some as high as 9 feet (2.75 meters) tall, are spaced at regular intervals around the hill, like a crown 100 feet (30 meters) in diameter.
On the shortest day of the year — Dec. 21 — the shadow of one of the blocks disappears when the sun is directly above it.
"It is this block's alignment with the winter solstice that leads us to believe the site was once an astronomical observatory," said Mariana Petry Cabral, an archaeologist at the Amapa State Scientific and Technical Research Institute. "We may be also looking at the remnants of a sophisticated culture."
The 127 blocks, some as high as 9 feet (2.75 meters) tall, are spaced at regular intervals around the hill, like a crown 100 feet (30 meters) in diameter.
On the shortest day of the year — Dec. 21 — the shadow of one of the blocks disappears when the sun is directly above it.
"It is this block's alignment with the winter solstice that leads us to believe the site was once an astronomical observatory," said Mariana Petry Cabral, an archaeologist at the Amapa State Scientific and Technical Research Institute. "We may be also looking at the remnants of a sophisticated culture."
Thursday, June 15, 2006
Study Reveals Biochemical Signature Of Cocaine Craving In Humans
Ask anyone who has been addicted to drugs and they'll tell you that the mere sight of someone using their drug of choice -- or even people, places, or objects associated with drug use -- can trigger an intense desire for the drug. Using sophisticated brain-imaging techniques at the U.S. Department of Energy's Brookhaven National Laboratory, scientists from the National Institute on Drug Abuse (NIDA), Brookhaven Lab, and the University of Pennsylvania have uncovered the brain chemistry that underlies such "cue-induced" craving in cocaine addicts. The work, which appears in the June 14, 2006 issue of the Journal of Neuroscience, suggests new targets for medications aimed at treating addiction.
Wednesday, June 07, 2006
Chemists Look Through Glass To Find Secrets That Are Less Clear
A new understanding of how glass is formed may assist with our understanding of everything from the design of golf club heads to the structure of the early universe.
Princeton chemists have found that the formation of glass -- a familiar substance that nonetheless retains some elusive scientific mysteries -- always occurs differently depending on how quickly a liquid substance is cooled into its solid form. Though the findings will likely dash the hopes of condensed matter physicists who have long sought in vain for what is known as an "ideal" glass transition, they may also one day contribute to industrialists' efforts to create better plastics and other useful polymers.
"Glasses can be formed from any substance, and the way their molecules interact places them somewhere at the border between solids and liquids, giving them some properties that manufacturers can exploit," said Sal Torquato, a professor of chemistry who is also affiliated with the Princeton Center for Theoretical Physics. "Golf club heads made of metallic glasses, for example, can make golf balls fly farther. While our research could be utilized by industry, it can actually help us understand any 'glassy' multi-particle system, such as the early universe -- which cosmologists have described as a glass."
Torquato emphasized that it would probably be years before such practical applications become a reality, and that the findings were most significant for advancing our fundamental understanding of how the state of matter known as glasses behaves.
The research team, which also includes Princeton's Aleksandar Donev, a graduate student in computational and applied mathematics, and Frank Stillinger, a senior theoretical chemist, will publish its findings in the June 6th issue of the journal, Physical Review Letters.
Princeton chemists have found that the formation of glass -- a familiar substance that nonetheless retains some elusive scientific mysteries -- always occurs differently depending on how quickly a liquid substance is cooled into its solid form. Though the findings will likely dash the hopes of condensed matter physicists who have long sought in vain for what is known as an "ideal" glass transition, they may also one day contribute to industrialists' efforts to create better plastics and other useful polymers.
"Glasses can be formed from any substance, and the way their molecules interact places them somewhere at the border between solids and liquids, giving them some properties that manufacturers can exploit," said Sal Torquato, a professor of chemistry who is also affiliated with the Princeton Center for Theoretical Physics. "Golf club heads made of metallic glasses, for example, can make golf balls fly farther. While our research could be utilized by industry, it can actually help us understand any 'glassy' multi-particle system, such as the early universe -- which cosmologists have described as a glass."
Torquato emphasized that it would probably be years before such practical applications become a reality, and that the findings were most significant for advancing our fundamental understanding of how the state of matter known as glasses behaves.
The research team, which also includes Princeton's Aleksandar Donev, a graduate student in computational and applied mathematics, and Frank Stillinger, a senior theoretical chemist, will publish its findings in the June 6th issue of the journal, Physical Review Letters.
Thursday, June 01, 2006
Ancient World Discovered in Israel
Israeli scientists say they have discovered a prehistoric ecosystem dating back millions of years.
The discovery was made in a cave near the central Israeli city of Ramle during rock drilling at a quarry. Scientists were called in and soon found eight previously unknown species of crustaceans and invertebrates similar to scorpions.
“Until now, eight species of animals were found in the cave, all of them unknown to science,” Hanan Dimantman, a biologist at the Hebrew University of Jerusalem, said Wednesday.
He said the cave’s ecosystem probably dates back around 5 million years, when the Mediterranean Sea covered parts of Israel. The cave was completely sealed off from the world, including from water and nutrients seeping through rock crevices above. Scientists who discovered the cave believe it has been intact for millions of years.
“Every species we examined had no eyes, which means they lost their sight due to evolution,” said Dimantman. Samples of the animals discovered in the cave were sent for DNA tests, which found they were unique, he said. The cave has been closed off as scientists conduct a more detailed survey.
“This is a cave of fantastic biodiversity,” Dimantman said
The discovery was made in a cave near the central Israeli city of Ramle during rock drilling at a quarry. Scientists were called in and soon found eight previously unknown species of crustaceans and invertebrates similar to scorpions.
“Until now, eight species of animals were found in the cave, all of them unknown to science,” Hanan Dimantman, a biologist at the Hebrew University of Jerusalem, said Wednesday.
He said the cave’s ecosystem probably dates back around 5 million years, when the Mediterranean Sea covered parts of Israel. The cave was completely sealed off from the world, including from water and nutrients seeping through rock crevices above. Scientists who discovered the cave believe it has been intact for millions of years.
“Every species we examined had no eyes, which means they lost their sight due to evolution,” said Dimantman. Samples of the animals discovered in the cave were sent for DNA tests, which found they were unique, he said. The cave has been closed off as scientists conduct a more detailed survey.
“This is a cave of fantastic biodiversity,” Dimantman said
