Update: February 12, 2008

JADE TO PLAGUE

By Pam Eastlick for THE DEEP on line

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

NETWORKS

Australian scientists have recently discovered something interesting about ancient Asian and Pacific trading routes.  They’ve discovered that virtually all the jade found all over Southeast Asia, the islands of Indonesia and Malaysia and Australia come from mines in Taiwan.

Their analysis of the origins of jade used in ancient jewelry has revealed a trading arena that was active for more than 3,000 years and sprawled over much of Southeast Asia – possibly the largest such network discovered in the region to date. An international research team led by archaeologists from The Australian National University used electron probe microanalysis to examine jade earrings excavated from sites all over Southeast Asia, and they pinpointed the origin of the precious stone to a source in Taiwan. Archaeologists had thought that the earrings were made from local jade by people as they migrated and traded across Southeast Asia – but the researchers have now shown that much of the stone came from Taiwan and was transported in raw form to places like the Philippines,

Borneo, central Vietnam and southern Thailand – thousands of miles by sea from its source. Of the 144 jade artifacts sampled, 116 specimens were traced back to eastern Taiwan. This is the first time that such a large trading network has been established in Southeast Asia. And speaking of large networks, geologists have recently found evidence of a huge one, underground.

NETWORKS, REVISITED

The mid-oceanic ridges zigzag across the floor of the World Ocean for at least 36,000 miles. In the late 1970’s, scientists discovered that there were vast plumbing systems under the ridges, which pull in cold water, superheat it, then spit it back out from seafloor vents; a process that brings up not only hot water, but dissolved substances taken from rocks below. Unique life forms feed off this warm stew that pours from these vents, and valuable minerals including gold may also be extruded. Now, a team of seismologists working on the East Pacific Rise beneath a mile and a half of water has created the first images of one of these systems; and it doesn’t work as they’d assumed it would. The original theory of circulation said that water is forced down by overlying pressure through large faults along the ridge flanks. The water is then heated by shallow volcanism and rises toward the ridges' middles, where vents (often called "black smokers," for the cloud of chemicals they exude) tend to cluster. The new images, from a mile-square area show a very different arrangement. In these new images, the water appears to descend through a 700-foot-wide chimney atop the ridge, run below the ridge along its axis through a tunnel-like zone just

above a magma chamber, and then bubble back up through a series of vents further along the ridge. The images were created using seismometers planted around the ridge to record tiny, shallow earthquakes--in this study, 7,000 of them, over 7 months in 2003 and 2004. Using new techniques developed by the researchers, the quakes were located with great precision. They cluster neatly, outlining the cold water's apparent entrance. It dives straight down through the ridge to a depth of about 2,000 feet, then fans out into a horizontal band about 600 feet wide before bottoming out at about a mile deep, just above the magma. Heated water rises back up through a dozen vents about a mile and a half north along the ridge. The researchers interpret the quakes as the result of cold water passing through hot rocks and picking up their heat--a process that shrinks the rocks, and cracks them, creating the small quakes. The researchers believe the water travels not through large faults--the model previously favored by some scientists--but through systems of tiny cracks. Furthermore, their calculations suggest that the water moves a lot faster than previously thought--perhaps a billion gallons per year through this particular system. Their chart of the water's route is reinforced by biologists' observations from submersible dives that the area around the downflow chimney is more or less lifeless, while the surging vents are a riot of bacterial mats, mussels, tubeworms, and other weird creatures that thrive off the heat and chemicals. Scientific research is not always a straightforward path. In 2006, a volcanic eruption buried most of the seismometers, but those that survived provided new information about how the eruptions work. This summer, researchers hope to return to generate unprecedented 3D images of the ridge's interior.

LEND ME YOUR EARS, AND THE WORLD WILL SOUND VERY DIFFERENT

Recognizing people, objects or animals by the sound they make is an important survival skill and something most of us take for granted. But similar objects can make very different sounds and we humans can pick up subtle clues about the identity and source of the sound. Scientists are discovering new things about the ways the human ear and the brain work together to help us understand our acoustic environment. One interesting new fact they’ve discovered is that everyone’s brain processes sound differently. We learn throughout our lives how to localize and identify different sounds and if you could hear the world through someone else's ears it would sound very different to what you are used to. A research team from the University of Oxford has discovered that each person's auditory cortex in their brain is adapted to way their ears deliver sound to them and their experience of the world. If you could borrow someone else's ears you would have real difficulty in locating the source of sounds, at least until your brain had relearned how to do it. The team has also discovered that the auditory cortex doesn’t have neurons that are sensitive to different aspects of sound. When the researchers looked at how the auditory cortex responds to changes in pitch, timbre and frequency they saw that most of the available neurons reacted to each change. This is intriguing because in the closely related visual cortex there are different neurons for processing color, form and motion. The auditory doesn’t seem to have neurons that are specifically for detecting changes in pitch or frequency. If they can understand how the auditory cortex has evolved they may be able to apply the knowledge to develop hearing aids that can blot out background noise and speech recognition systems that can handle different accents. This research is being done by fitting trained ferrets with harmless auditory implants. The animals are trained to respond to different sounds and the implants enable the team to observe the auditory neurons as the ferret responds to different sounds. The researchers hope that this study will help reveal how our senses work and how the brain interprets information from the ears and they may bring exciting developments in helping people with hearing and other disabilities. Most animals have some sort of system to detect sounds and now there’s research being done on one of the most primitive animals that performs another common biological function: sleep.

KNIT UP THOSE RAVELED NERVES

The roundworm C. elegans, a staple of laboratory research, may be key in unlocking one of the central biological mysteries: why we sleep. Researchers at the University of Pennsylvania School of Medicine report that the round worm has a sleep-like state, joining most of the animal kingdom in displaying this physiology. The research has implications for explaining the evolution and purpose of sleep and sleep-like states in animals.

By demonstrating that roundworms sleep, the researchers have not only demonstrated the ubiquity of sleep in nature, but also propose a compelling hypothesis for the purpose for sleep. C. elegans ‘sleeps in a time in its life cycle when synaptic changes occur in the nervous system and for this reason the researchers propose that sleep is a state required for nervous system plasticity. In other words, in order for the nervous system to grow and change, there must be down time from active behavior. Other researchers have shown that, in mammals, synaptic nerve changes occur during sleep and that deprivation of sleep results in a disruption of these synaptic changes.

THEY’RE EVERYWHERE, THEY’RE EVERWHERE

In a surprising and disturbing study, Swedish researchers report that birds captured on the tundra above the Arctic Circle were carriers of antibiotic-resistant bacteria. These findings indicate that resistance to antibiotics has spread into nature, which is an alarming prospect for future health care. The scientists took samples from 97 birds in northeastern Siberia, northern Alaska, and northern Greenland. These samples were cultivated directly in special laboratories that the researchers had installed onboard the icebreaker Oden and were further analyzed at the microbiological laboratory at Central Hospital in Växjö, Sweden.

They found that the commonly prescribed 325 mg adult tablet may be more than many people need each day. The study found that doses higher than a baby aspirin, 75 to 81 mg, are no better at preventing cardiovascular events long-term and are associated with increased risk of gastrointestinal bleeding. Even in patients with diabetes, who may be more difficult to treat, they found no large-scale studies that support higher doses of aspirin. Aspirin is the most-used drug in the world. More than 50 million people, or 36 percent of the adult population in the United States, consume 10 to 20 billion aspirin tablets each year to protect their hearts from clots, which are the leading cause of heart attacks and strokes. “Patients should check with their doctor to be sure, but there is almost no one who needs to take more than 81 mg of aspirin a day for protection from heart attacks,” one of the researchers said. As someone who bleeds like a stuck pig on a 325 mg daily dose, I say “Amen” to the latest research! And speaking of the latest research.One of the scientists said "We took samples from birds living far out on the tundra that had no contact with people. This further confirms that resistance to antibiotics has become a global phenomenon and that virtually no region of the earth, with the possible exception of the Antarctic, is unaffected." The researchers' hypothesis is that immigrating birds have passed through regions in Southeast Asia, for example, where there is a great deal of antibiotics pressure and carried the resistant bacteria with them to the tundra. The findings show that resistance to antibiotics is not limited to society and hospitals but is now spreading into the wild. Escalating resistance to antibiotics over the last few years has crystallized into one of the greatest threats to health care in the future.

IT’S B-A-A-A-CK

Probably the two most feared diseases ever are leprosy and plague. We’ve discovered over the years that though leprosy is horrible, it’s the least contagious of the contagious diseases, and there were many, many diseases that were lumped under the ‘leprosy’ tag in times past. Leprosy was never the horrible threat that was attributed to it. However, that doesn’t apply to plague.

Plague wiped out a quarter of the human race in the 1300’s and despite our best efforts, it has never gone away. Although plague is often thought of as a disease of the past, it remains a current threat in many parts of the world, and the number of countries reporting plague has increased in recent decades, says a team of researchers. Following the re-appearance of plague in the 1990s, particularly in Africa, the disease has been classified as re-emerging. The plague bacillus, Yersinia pestis, causes several thousand human cases per year. In recent years, there has been a major shift in cases from Asia to Africa, with more than 90% of all cases and deaths in the last five years occurring in Madagascar, Tanzania, Mozambique, Malawi, Uganda, and the Democratic Republic of the Congo (DRC). Most are cases of bubonic plague contracted through contact with infected rodents and fleas, although outbreaks of pneumonic plague (directly transmitted from human to human via inhalation of infected respiratory droplets) still occur. The most recent large pneumonic plague outbreak was in October and November 2006 in the DRC, with hundreds of suspected cases. A smaller outbreak arose just across the border in nearby Uganda in February 2007. The scientists have a dire warning in their report. "Plague may not match the so-called 'big three' diseases (malaria, HIV/AIDS, tuberculosis) in numbers of current cases, but it far exceeds them in pathogenicity and rapid spread under the right conditions." "It’s easy to forget plague in the 21st century, seeing it as a historical curiosity. But in our opinion, plague should not be relegated to the sidelines. It remains a poorly understood threat that we cannot afford to ignore." Cruise on over to the Deep Website at www.thedeepradioshow.com to learn more about jade, sleep, plague and many other topics. Enjoy!