December 13, 2006, 4:25 AM CT

Is it true that no two snowflakes are alike?

Snowflakes are one of the most recognizable and endearing symbols of winter. Their intricate shapes have been the inspiration for Christmas ornaments, jewelry and U.S. postage stamps. They are the subject of song, school projects and even scientific investigation, including a possible impact on global warming.

Jon Nelson, a researcher with Ritsumeikan University in Japan, has studied snowflakes for 15 years, and has some interesting insights into their delicate structures.

Is it true that no two snowflakes are alike?

The old adage that 'no two snowflakes are alike' may ring true for larger snowflakes, but it might not hold true for smaller, simpler crystals that fall before they've had a chance to fully develop. Regardless, snow crystals have tremendous diversity, partly due to their very high sensitivity to tiny temperature changes as they fall through the clouds.

How do snowflakes form?

A snowflake starts as a dust grain floating in a cloud. Water vapor in the air sticks to the dust grain and the resulting droplet turns directly into ice. And that's where the science kicks in.

First, the tiny ice crystal becomes hexagonal (six-sided). This shape originates from the chemistry of the water molecule, which consists of two hydrogen atoms bonded to an oxygen atom. Because of the angle of the water molecule and its hydrogen-bonding, the water molecules in a snowflake chemically bond to each other to form the six-sided flake. The flake eventually sprouts six tiny branches. Each of these branches grows to form side branches in a direction and shape that are influenced by the clustering of water molecules on the ice crystal surfaces.........

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December 12, 2006, 4:56 AM CT

Excavating Site Around First Baptist Church

Providence's First Baptist Church is the oldest Baptist church in America - but how was the area and its grounds used before The Meeting House was built in 1775? A group of Brown University students enrolled in Anthropology 160 are investigating that question while learning archaeological techniques, as they excavate the property surrounding this historical site.

Students at Brown University are conducting an archaeological dig on the property surrounding the First Baptist Church in Providence, at the invitation of the congregation. In addition to providing undergraduate students an opportunity to participate in hands-on archaeological research and excavation training without leaving campus, the project may document an important part of city history.

The excavations are part of Anthropology 160, sponsored by Brown University's Anthropology Department and the Artemis A.W. and Martha Sharp Joukowsky Institute for Archaeology and the Ancient World. The field directors are Zachary Nelson, a postdoctoral research associate in anthropology, and Katherine Marino, a doctoral candidate at the Joukowsky Institute.

"Archaeological practice can not be wholly described with words," Nelson said. "There is a necessary experiential element to archaeological work that can only be achieved through actual practice".........

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December 11, 2006, 4:53 AM CT

Birth Pangs of Earth's Crust

Forsyth and Saal, professors of geology at Brown University, were returning from a research cruise to map an area of seafloor near the Galapagos Islands last April, along with seven Brown graduate students and four undergraduates. The cruise route took the ship right by a highly studied section of the mid-ocean ridge called the East Pacific Rise. The area had experienced an episode of seafloor spreading in 1991 and was being closely monitored as part of the RIDGE2000 program sponsored by the National Science Foundation.

A team of researchers headed by Maya Tolstoy, a geologist at Columbia's Earth Institute, had placed an array of ocean-bottom seismometers (OBS) at the spot in 2003 and collected data from the vibration-recording devices at least once a year. With ship-time at a premium, it's common for a research ship to make a quick stop to download such data.

The task should have been simple. The seismometers are anchored to the seafloor by a mechanism that will release them and allow them to float to the surface when triggered by an acoustic signal. The crew and researchers scoop up the microwave-oven-sized devices and return them to shore, replacing them with new ones that will monitor seismic activity for the next year. It's uncommon for an OBS to be lost due to mechanical malfunction.........

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December 10, 2006, 6:21 PM CT

Extreme Life

A host of record-breaking discoveries and revelations that stretch the extreme frontiers of marine knowledge were achieved by the Census of Marine Life in 2006, highlights of which were released recently.

They include life adapted to brutal conditions around 407ºC fluids spewing from a seafloor vent (the hottest ever discovered), a mighty microbe 1 cm in diameter, mysterious 1.8 kg (4 lb) lobsters off the Madagascar coast, a US school of fish the size of Manhattan Island, and more unfamiliar than familiar species turned up beneath 700 meters of Antarctic ice.

Now in its 6th year, Census participants and their supporters pool talents and specialties, ships and laboratories, archives and technology in an unprecedented global scientific collaboration. Together, they are systematically recording the diversity, distribution, and abundance of global marine life. The most intense field work is taking place in 2006-8; the results will be analysed and synthesized in 2009-10 with the goal by 2010 of an initial census describing what lived, now lives, and will live in the oceans.

Census researchers mounted 19 ocean expeditions in 2006 (a 20th expedition underway in the Antarctic can be followed online at www.awi.de/MET/Polarstern/psobse.html). They inventoried nearshore biodiversity, where the number of active sampling sites grew exponentially from 30 to 128 in 2006 alone. And, using satellites, they followed across thousands of kilometers of ocean more than 20 tagged species - from sharks and squid to sea lions and albatross.........

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December 5, 2006, 8:57 PM CT

How Ocean Could Slow Global Warming

The Southern Hemisphere westerly winds have moved southward in the last 30 years. A new climate model predicts that as the winds shift south, they can do a better job of transferring heat and carbon dioxide from the surface waters surrounding Antarctica into the deeper, colder waters.

The Southern Ocean may slow the rate of global warming by absorbing significantly more heat and carbon dioxide than previously thought, as per new research.

The new finding surprised the scientists, said lead researcher Joellen L. Russell. "We think it will slow global warming. It won't reverse or stop it, but it will slow the rate of increase."

The new model Russell and her colleagues developed provides a realistic simulation of the Southern Hemisphere westerlies and Southern Ocean circulation.

Prior climate models did not have the winds properly located. In simulations of present-day climate, those models distorted the ocean's response to future increases in greenhouse gases.

"Because these winds have moved poleward, the Southern Ocean around Antarctica is likely to take up 20 percent more carbon dioxide than in a model where the winds are poorly located," said Russell, an assistant professor of geosciences at The University of Arizona in Tucson.........

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December 1, 2006, 5:08 AM CT

Theory Of Oscillations May Explain Biological Mysteries

New mathematical studies of the interactions between oscillating biological populations may shed light on some of the toughest questions in ecology, including the number and types of species in an ecosystem, as per an article in the December 2006 issue of BioScience. The article, by John Vandermeer of the University of Michigan, shows how extensions of established theory suggest that a number of animal and plant populations oscillate in synchrony because of interactions such as predation and competition. Such synchronization can have far-reaching effects. Vandermeer suggests that several well-known biological conundrums, such as the higher-than-expected diversity of plankton in aquatic ecosystems, may be explained this way.

Physicists know that even a weak coupling between oscillating systems can yield synchronized oscillations, a phenomenon that was studied with pendulums by the seventeenth century Dutch mathematician Christiaan Huygens. Biologists have only in recent years started to explore the implications for their subject. But it is already clear that coupled oscillating biological populations can give rise to potentially important effects such as synchronized chaos: the interaction between two weakly competing consumers of a food resource can be transformed by the arrival of a third competitor to provide unpredictable opportunities for the newcomer to invade. Vandermeer holds out hopes that the study of oscillations in biological populations will lead to insights into complex systems, such as those that include animals that eat other predators as well as omnivores that eat both predators and those predators prey.........

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December 1, 2006, 4:40 AM CT

PTSD Drug Is No More Effective Than Placebo

Guanfacine, a medicine commonly prescribed to alleviate symptoms of post-traumatic stress disorder, is no more effective than a placebo, according to a study led by researchers at the San Francisco VA Medical Center.

There was no benefit at all, and there were several adverse side effects, says lead author Thomas Neylan, MD, medical director of the PTSD treatment program at SFVAMC. People with symptoms of PTSD should probably stay away from this drug and others of its type.

The study appears in the December 1, 2006 issue of the American Journal of Psychiatry.

Guanfacine belongs to a class of medications known as alpha-2 agonists, which lower the brains supply of the neurotransmitter norepinephrine. Neurotransmitters are chemicals that transmit electrical signals between nerve cells. They are responsible for many aspects of behavior.

Norepinephrine is released in the brain during states of excited arousal, and PTSD is associated with that state patients startle easily, have trouble sleeping, and are hypervigilant and anxious, explains Neylan, who is also an associate professor of psychiatry at the University of California, San Francisco.

Guanfacine and clonidine, another alpha-2 agonist, are commonly prescribed for PTSD symptoms. There are at least 20 peer-reviewed articles published in the field of PTSD that recommend drugs which lower norepinephrine, Neylan says. However, ours was the first randomized, controlled study of alpha-2 agonists for symptoms of PTSD.........

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December 1, 2006, 4:19 AM CT

Preparing Food Helps Young Adults Eat Better

Young adults who often purchase their own food and prepare meals at home eat fast food less often, eat more fruits and vegetables and have better overall diet quality than those who are not involved in planning and cooking their meals, according to researchers at the University of Minnesota.

The study surveyed more than 1,500 people ages 18 to 23 about their food purchasing and preparation habits and the quality of their diets. The researchers found 31 percent of those surveyed who reported high involvement in meal preparation also consume five servings of fruits or vegetables daily, compared with three percent of those who reported very low involvement in meal preparation. Eighteen percent of the "high participation" group met guidelines for consuming servings of deep-yellow or green vegetables, compared with just 2 percent of the "very low involvement" group.

The researchers found the young adults most likely to be involved with food preparation and purchasing in association tend to be female; Asian, Hispanic or white; and eating at fast-food restaurants fewer than three times per week. Still, even among study participants who were very involved in food preparation, the study found many young adults do not meet recommended dietary guidelines in what they eat. "Cooking skills, money to buy food and time available for food preparation were perceived as inadequate by approximately one-fifth to more than one-third of the sample." The researchers conclude: "To improve dietary intake, interventions among young adults should teach skills for preparing quick and healthful meals".........

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November 30, 2006, 5:16 AM CT

Fortified Milk For Preschool Children

Consumption of milk fortified with specific micronutrients-zinc, iron, selenium, copper, vitamin A, vitamin C and vitamin E-significantly reduces diarrhea and acute lower respiratory illness among children in developing countries, as per scientists from the Johns Hopkins Bloomberg School of Public Health and the Center for Micronutrient Research at Annamalai University in India. The study was published November 28, 2006, on the website of the British Medical Journal.

"Some micronutrients have a crucial role in generation, maintenance and amplification of immune responses in the body. Deficiencies in multiple micronutrients among preschool children are an important determinant of child health in developing countries," said Sunil Sazawal, MD, MPH, PhD, lead author of the study and an associate professor in the Bloomberg School of Public Health's Department of International Health.

The authors conducted a randomized, controlled trial among 633 children aged 1-4 years in a peri-urban population in New Delhi, India, from April 2002-April 2004. An intervention group of 316 children received milk fortified with additional micronutrients-7.8 mg zinc, 9.6 mg iron, 4.2 µg selenium, 0.27 mg copper, 156 µg vitamin A, 40.2 mg vitamin C and 7.5 mg vitamin E-while a control group of 317 children received the same milk without fortification. The study was undertaken in children over 12 months of age, of which breast feeding is not the primary source of nutrition.........

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November 30, 2006, 5:09 AM CT

Mystery About Stradivarius Violins Solved

Answering a question that has lingered for centuries, a team of researchers has proved that chemicals used to treat the wood used in Stradivarius and Guarneri violins are the reasons for the distinct sound produced by the world-famous instruments.

The conclusions, reported in the current issue of Nature magazine, have confirmed 30 years of work into the subject by Joseph Nagyvary, professor emeritus of biochemistry at Texas A&M University, who was the first to theorize that chemicals not necessarily the wood created the unique sound of the two violins. Nagyvary teamed with collaborators Joseph DiVerdi of Colorado State University and Noel Owen of Brigham Young University on the project.

This research proves unquestionably that the wood of the great masters was subjected to an aggressive chemical therapy and the chemicals most likely some sort of oxidizing agents had a crucial role in creating the great sound of the Stradivarius and the Guarneri, Nagyvary says.

Like a number of discoveries, this one could have been accidental. Perhaps the violin makers were not even aware of the acoustical effects of the chemicals. Both Stradivari and Guarneri wanted to treat their violins to prevent worms from eating away the wood. They used some chemical agents to protect the wood from worm infestations of the time, and the unintended consequence from these chemicals was a sound like none other, he adds.........

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