Thursday, December 24, 2009

STUDYING HAIR OF ANCIENT PERUVIANS ANSWERS QUESTIONS ABOUT STRESS

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Recent studies show that one in three Canadians suffer from stress and the number is on the rise. But stress isn't a new problem.

While the physiological state wasn't properly named until the 1930s, new research from The University of Western Ontario proves stress has plagued humans for hundreds, and perhaps thousands of years.

The first study of its kind, published in the Journal of Archaeological Science, detected the stress hormone cortisol in the hair of ancient Peruvians, who lived between 550 and 1532 A.D.

When an individual is stressed – due to real or perceived threats – cortisol is released into nearly every part of the body, including blood, saliva, urine and hair.

Emily Webb, a PhD candidate at Western in Archaeological Science and the study's lead author, says the findings are important because it will allow us to better understand how ancient people behaved and felt during their time on Earth but more importantly, to better understand stress and how it affects us today.

"By studying the lives of people using traditional archeological methods like surveying and excavation and combining that with new research techniques like sampling ancient hair specimens, we can get a good picture of what life was like and how our ancestors may have responded to life-changing experiences like illness and disease," explains Webb.

Analysis of cortisol levels in ancient hair allows researchers to assess stress during a short, but critical, period of an individual's life. For this pilot study, the Western researchers selected hair samples from 10 individuals from five different archaeological sites in Peru, and analyzed them in segments to determine cortisol levels.

While many of the individuals studied showed high stress levels right before death, Webb noted that a majority also experienced multiple episodes of stress throughout their final years of their life, again proving that much like today, stress was very much apart of ancient Peruvian's daily lives.

University of Western Ontario

SUPER COOL ATOM THERMOMETER

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As physicists strive to cool atoms down to ever more frigid temperatures, they face the daunting task of developing new, reliable ways of measuring these extreme lows. Now a team of physicists has devised a thermometer that can potentially measure temperatures as low as tens of trillionths of a degree above absolute zero.

Physicists can currently cool atoms to a few billionths of a degree, but even this is too hot for certain applications. For example, Richard Feynman dreamed of using ultracold atoms to simulate the complex quantum mechanical behavior of electrons in certain materials. This would require the atoms to be lowered to temperatures at least a hundred times colder than what has ever been achieved. Unfortunately, thermometers that can measure temperatures of a few billionths of a degree rely on physics that doesn't apply at these extremely low temperatures.

Now a team at the MIT-Harvard Center for Ultra-Cold Atoms has developed a thermometer that can work in this unprecedentedly cold regime. The trick is to place the system in a magnetic field, and then measure the atoms' average magnetization. By determining a handful of easily-measured properties, the physicists extracted the temperature of the system from the magnetization. While they demonstrated the method on atoms cooled to one billionth of a degree, they also showed that it should work for atoms hundreds of times cooler, meaning the thermometer will be an invaluable tool for physicists pushing the cold frontier.

(Photo: Alan Stonebraker)

CSIRO RESEARCHERS CREATE GIANT WAVES

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CSIRO scientists have created ‘rogue waves’ more than 20 metres high and smashed them into virtual oil and gas production platforms to compare different mooring designs.

The computer modelling project compares how different types of semi-submersible oil rigs withstand the effects of giant waves in the open ocean.

Rogue waves are rare, extreme events that pose a risk to shipping and offshore structures and can lead to loss of life.

They differ from tsunamis, which only grow large when they reach shallow water.

CSIRO scientist and keen surfer, Dr Murray Rudman, said rogue waves were once considered folklore, but wave height monitoring data has blown that myth out of the water.

“Rogue waves are huge waves that sometimes seem to come out of nowhere and, in recent years, they’ve been a major topic of scientific research,” Dr Rudman said.

CSIRO is using fluid-flow mathematics and computer modelling to assist in the sensible and safe design of oil platforms.

Modelling rogue waves’ effects enables researchers to conduct experiments – which would normally involve the use of huge water tanks – more cheaply, accurately and quickly.

“Waves are extremely difficult to predict, especially when they begin to break,” Dr Rudman said. “Also, the movement of the wave and the oil platform influence each other in complex ways.

“We use a mathematical technique called Smoothed Particle Hydrodynamics originally developed in astrophysics to model stars forming and galaxies exploding.

“In CSIRO, we’ve extended the methods to a whole range of industrial applications.”

Using the technique on a computer, the researchers can create a realistic rogue wave and pound the four legs and platform of the oil rig, which is floating on the ocean but tethered to the ocean floor by cables.

Various cable mooring systems and materials can be compared.

The computer measures the movement of the platform in many different directions over a particular time period to see how well the moorings hold.

The results show the forces the wave impact generates on the structure and cables to see if anything breaks. Researchers can even see what happens when an oil rig capsizes.

CSIRO is applying similar techniques to modelling dam breaks and landslides.

(Photo: CSIRO)

The Commonwealth Scientific and Industrial Research Organisation (CSIRO)

LIFE ON MARS THEORY BOOSTED BY NEW METHANE STUDY

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Scientists have ruled out the possibility that methane is delivered to Mars by meteorites, raising fresh hopes that the gas might be generated by life on the red planet, in research published in Earth and Planetary Science Letters.

Methane has a short lifetime of just a few hundred years on Mars because it is constantly being depleted by a chemical reaction in the planet’s atmosphere, caused by sunlight. Scientists analysing data from telescopic observations and unmanned space missions have discovered that methane on Mars is being constantly replenished by an unknown source and they are keen to uncover how the levels of methane are being topped up.

Researchers had thought that meteorites might be responsible for Martian methane levels because when the rocks enter the planet’s atmosphere they are subjected to intense heat, causing a chemical reaction that releases methane and other gases into the atmosphere.

However, the new study, by researchers from Imperial College London, shows that the volumes of methane that could be released by the meteorites entering Mars’s atmosphere are too low to maintain the current atmospheric levels of methane. Previous studies have also ruled out the possibility that the methane is delivered through volcanic activity.

This leaves only two plausible theories to explain the gas’s presence, according to the researchers behind today’s findings. Either there are microorganisms living in the Martian soil that are producing methane gas as a by-product of their metabolic processes, or methane is being produced as a by-product of reactions between volcanic rock and water.

Co-author of the study, Dr Richard Court, Department of Earth Science and Engineering at Imperial College London, says:

“Our experiments are helping to solve the mystery of methane on Mars. Meteorites vaporising in the atmosphere are a proposed methane source but when we recreate their fiery entry in the laboratory we get only small amounts of the gas. For Mars, meteorites fail the methane test.”

The team say their study will help NASA and ESA scientists who are planning a joint mission to the red planet in 2018 to search for the source of methane. The researchers say now that they have discovered that meteorites are not a source of Methane on Mars, ESA and NASA scientists can focus their attention on the two last remaining options.

Co-author, Professor Mark Sephton, Department of Earth Science and Engineering at Imperial College London, adds:

“This work is a big step forward. As Sherlock Holmes said, eliminate all other factors and the one that remains must be the truth. The list of possible sources of methane gas is getting smaller and excitingly, extraterrestrial life still remains an option. Ultimately the final test may have to be on Mars.”

The team used a technique called Quantitive Pyrolysis-Fourier Transform Infrared Spectroscopy to reproduce the same searing conditions experienced by meteorites as they enter the Martian atmosphere. The team heated the meteorite fragments to 1000 degrees Celsius and measured the gases that were released using an infrared beam.

When quantities of gas released by the laboratory experiments were combined with published calculations of meteorite in-fall rates on Mars, the scientists calculated that only 10 kilograms of meteorite methane was produced each year, far below the 100 to 300 tonnes required to replenish methane levels in the Martian atmosphere.

(Photo: ICL)

Imperial College London

TRANSCRIPTION FACTORS GUIDE DIFFERENCES IN HUMAN AND CHIMP BRAIN FUNCTION

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Humans share at least 97 percent of their genes with chimpanzees, but, as a new study of transcription factors makes clear, what you have in your genome may be less important than how you use it.

The study, in Proceedings of the National Academy of Sciences, found that broad differences in the gene activity of humans and of chimpanzees, affecting nearly 1,000 genes, appear to be linked to the action of about 90 transcription factors.

Transcription factors are proteins that bind to specific regions of the DNA to promote or repress the activity of many genes. A single transcription factor can spur the transcription of dozens of genes into messenger RNA (mRNA), which is then translated into proteins that do the work of the cell. This allows specific organs or tissues to quickly ramp up a response to an environmental change or internal need.

Previous studies have found differences in gene expression between humans and chimps, particularly in the brain. Genes involved in metabolism or protein transport, for example, are translated into mRNAs at a much higher level in human brains than in the smaller brains of chimpanzees.

This makes sense, said University of Illinois cell and developmental biology professor Lisa Stubbs, who led the new analysis with postdoctoral researcher Katja Nowick.

“These differences fit what we know because the human brain is so much larger and proteins need to be shuttled a long way out to the synapses,” Stubbs said. “A higher requirement for metabolic energy has also been demonstrated independently for human brains.”

What wasn’t clear from previous studies was how this upsurge in gene activity was coordinated, she said.

Stubbs has had a longtime interest in the evolutionary role of transcription factors and other regulatory agents in the genome. She is particularly interested in the largest family of transcription factors in mammals, the KRAB zinc finger (KRAB-ZNF) genes, which on average have accumulated more differences in sequence between humans and chimps than other genes.

“There are a lot of unique new transcription factors that arise in this family,” Stubbs said. “And they arise by duplication of older genes. So the genes make a new copy of themselves and then that new copy takes on a slightly different or even dramatically different function.”

“Our very strong bias is to believe that these transcription factors are involved in speciation and traits that make species unique,” she said.

Nowick, who studies human and primate evolution, was part of a team (at the Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany) that analyzed differences in gene expression between humans and chimps.

In the new study, Nowick and computer scientist Tim Gernat, a co-author, took a new look at data from that study, which tracked gene expression – including genes coding for transcription factors – in tissues from six humans and five chimpanzees.

“Katja and Tim came up with a strategy for cleaning up the data and looking at these genes more uniquely,” Stubbs said. “It hadn’t been done before.”

The analysis revealed a broad pattern of activity in 90 transcription factors that paralleled the activity of about 1,000 genes in humans and chimps.

The KRAB-ZNF genes were the most common members of this group, but many other transcription factors were also involved. Some were activators and some were repressors, but their activity coincided with a general upsurge of these genes in human brains.

Eivind Almaas, a researcher at the Norwegian University of Science and Technology and a co-author on the study, developed a gene regulatory network diagram of the transcription factors in relation to the genes that rise or fall with them. The proximity of one transcription factor to another in the network depended on the degree of overlap of the lists of genes that correlate with each. Almaas created one network diagram for humans and another for chimps, and uncovered some interesting differences.

“The chimp network looks very much like the human one except there are a few transcription factors in different positions and with different connectivity,” Stubbs said. “Those are of interest from the point of view that they signal a major gene regulatory shift between species, and this shift may help us explain some of the biological differences.”

The new findings indicate that certain transcription factors are working together in a coordinated way to regulate the changes in seen in gene expression between humans and chimps, the researchers said.

“Once this network of transcription factors is established, changes in the network can be amplified because transcription factors control other genes,” Nowick said. “Even a small change in transcription factor expression can therefore produce a large effect on overall gene expression differences between chimpanzees and humans.”

(Photo: Edwin Hadley, University of Illinois)

University of Illinois

THINK AGAIN ABOUT KEEPING LITTLE ONES SO SQUEAKY CLEAN

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A new Northwestern University study suggests that American parents should ease up on antibacterial soap and perhaps allow their little ones a romp or two in the mud --- or at least a much better acquaintance with everyday germs.

The study is the first to look at how microbial exposures early in life affect inflammatory processes related to diseases associated with aging in adulthood.

Most provocatively, the Northwestern study suggests that exposure to infectious microbes early in life may actually protect individuals from cardiovascular diseases that can lead to death as an adult.

"Contrary to assumptions related to earlier studies, our research suggests that ultra-clean, ultra-hygienic environments early in life may contribute to higher levels of inflammation as an adult, which in turn increases risks for a wide range of diseases," said Thomas McDade, lead author of the study, associate professor of anthropology in Northwestern's Weinberg College of Arts and Sciences and a faculty fellow at the Institute for Policy Research (IPR).

Relatively speaking, humans only recently have lived in such hyper-hygienic environments, he stressed.

The research suggests that inflammatory systems may need a higher level of exposure to common everyday bacteria and microbes to guide their development. "In other words, inflammatory networks may need the same type of microbial exposures early in life that have been part of the human environment for all of our evolutionary history to function optimally in adulthood," said McDade, also a member of the Institute for Policy Research's Cells to Society (C2S).

The Northwestern study is the first research on microbial effects on inflammatory systems in infancy that relate in later life to diseases associated with aging. Advancing the scientific literature on the developmental origins of disease, the study arguably is the most significant research on long-term effects of early environments on human physiological function and health in adulthood.

The research took advantage of a longitudinal study of Filipinos, following participants in utero through 22 years of age, to get a better understanding of how environments early in life affect C-reactive protein (CRP) production in adulthood.

Levels of the protein rise in the blood due to inflammation, an integral part of the immune system's fight against infection. CRP research mostly has centered on the protein as a predictor of heart disease, independent of lipids, cholesterol and blood pressure, though researchers still dispute that association. Researchers have been looking at excess body fat as a primary source of pro-inflammatory cytokines that produce CRP and behavioral factors related to diet, exercise and smoking. And the CRP research largely has been conducted in relatively affluent settings, such as in the United States, with low levels of infectious diseases.

The Northwestern researchers were interested in what CRP production looks like in the Philippines, a population with a high level of infectious diseases in early childhood compared to Western countries. Relative to Western countries, the Philippines also has relatively low rates of obesity and cardiovascular diseases, consistent with the Northwestern research findings.

Blood tests showed that C-reactive protein was at least 80 percent lower for study participants in the Philippines when they reached young adulthood, relative to their American counterparts, though the Filipinos suffered from many more infectious diseases as infants and toddlers. Filipino participants in their early 20s had average CRP concentrations of .2 milligrams per liter -- five to seven times lower than average CRP levels for Americans. CRP concentrations for Americans in their early 20s were on average around 1 to 1.5 milligram per liter.

The Northwestern study drew its data from a longitudinal study that began in the early 1980s with 3,327 Filipino mothers in the third trimester of pregnancy. The mothers were interviewed for behaviors related to care giving, and breast feedings were recorded. The household environment was assessed in terms of socioeconomic resources, hygiene (whether domestic animals, such as pigs and dogs, roamed freely) and density of inhabitants.

Researchers visited with the mothers at the delivery of their infants and subsequently every two months for the first two years of the children's lives. Thereafter, the researchers followed up with the children every four or five years until they reached their early 20s. The records they kept on the children include data on infectious diseases, growth in height and weight.

"In the U.S we have this idea that we need to protect infants and children from microbes and pathogens at all possible costs," McDade concluded. "But we may be depriving developing immune networks of important environmental input needed to guide their function throughout childhood and into adulthood. Without this input, our research suggests, inflammation may be more likely to be poorly regulated and result in inflammatory responses that are overblown or more difficult to turn off once things get started."

Northwestern University

NEW, EFFICIENT TRANSISTOR COULD ONE DAY POWER LAPTOPS, CARS

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A Cornell researcher has created an extremely efficient transistor made from a material that may soon replace silicon as king of semiconductors for power applications.

Junxia Shi, a graduate student in the laboratory of Lester Eastman, the John Given Foundation Professor of Engineering, developed the gallium nitride-based device, which could form the basis for the circuitry in products from laptops to hybrid vehicles to windmills to other power electronic systems.

The patent-pending device is a basic electrical switch made from the compound gallium nitride, a material with unique electrical properties that Eastman and colleagues have been studying for more than a decade. Research on their recent breakthrough was published July 28 in the journal Applied Physics Letters.

The new transistor's on-resistance, or measure of resistance to electric current, is 10 to 20 times lower than today's silicon-based power devices. It also has a high breakdown voltage, which is a measure of how much voltage can be applied across a material before it fails.

The key to the device lie in gallium nitride's low electrical resistance, causing less power loss to heat, and its ability to handle up to 3 million volts per centimeter without electrical failure. Silicon, a competing material, can handle only about 250,000 volts per centimeter.

At the heart of improving electronics, Eastman said, is the ability to make devices that can switch electricity from high voltage to high current, which is a measurement of electrical applicability, while minimizing power loss.

"Power has to go from A to B in a machine with a high voltage transmission line to minimize power loss," Eastman said. "Before now, there were no electronic devices that could handle both high current and the high voltage, but our device can do it."

The transistors, which were made with Cornell nanofabrication equipment, might one day power everything from hybrid electric vehicles to Navy destroyers. In fact, the U.S. Navy first funded Cornell's research into gallium nitride transistors more than 10 years ago and is a major funder of Eastman's research today.

In next-generation electrical devices, "you want to have the power that's coming out to be not much less than the power that's going in," Eastman said. "This is the best material we know of that can do this conversion without loss of energy."

Shi and Eastman have a provisional patent on their device. The New Jersey-based company Velox and Motorola spinoff Freescale have also helped fund the research, with the hope of producing the devices at an industrial scale.

(Photo: Junxia Shi)

University of Cornell

WHY KING KONG FAILED TO IMPRESS

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Humans have the same receptors for detecting odors related to sex as do other apes and primates. But each species uses them in different ways, stemming from the way the genes for these receptors have evolved over time, according to Duke University researchers.

Varying sensitivity to these sex-steroid odors may play a role in mate selection -- and perhaps prevent cross-species couplings, the researchers speculate.

The researchers analyzed the sequences and functions of the gene for the odorant receptor OR7D4 in terms of perceiving two steroid molecules related to testosterone, androstenone and androstadienone. The study did not try to examine how the receptors and odor perception might relate to behavior.

“There’s variation in sensitivity of the odorant receptor from this gene (all primates) have,” said Hiroaki Matsunami, associate professor of molecular genetics and microbiology and neurobiology at Duke University Medical Center. “Maybe these molecules operate in the process of reproduction. The fact that there is variation fits with this theory. Reproduction demands that an animal avoid attraction to other species, so variation in the receptor’s sensitivity to these odors may prevent any cross-species attraction.”

The study was published online Dec. 3 in the Early Edition of the Proceedings of the National Academy of Sciences.

Animals rely on olfactory signals to make all sorts of decisions about other animals, particularly in reproduction, said Christine Drea, Ph.D., an associate professor of Biology at Duke who was not involved with this study. “Beyond identifying members of the same species, odors help identify kin or nonkin, members of the opposite sex, even whether individuals are fertile or genetically appropriate as mates. How they do so is still largely unknown," she said. "By deciphering evolutionary changes in receptor function across species, Dr. Matsunami and his colleagues have brought us another step closer to unraveling the mysteries of olfactory signaling.”

The odorant receptor gene, which the paper traces back to the mongoose lemur, evolved differently within the various primate species. Human receptors were found to be most closely related to the chimps and bonobo monkeys, as opposed to gorillas and other primates.

The findings support the evidence that primates have a common ancestor, but we are very different now. “One of the differences is in how well we are able to sense odors, which is exemplified by changes in the function of this odor receptor,” Matsunami said.

Ultimately, the work will aim at discerning how smelling these chemicals might affect human social and sexual behavior. “We will begin working with a collaborator to examine chimpanzee behavior with regard to odor perception,” Matsunami said.

However, the sense of smell also can vary from animal to animal and person to person, because of combinations of a number of odor receptors.

“The sex-steroid related odors act as pheromones in pigs,” Matsunami said. “Pigs that are ovulating and that are exposed to the pheromones assume a mating posture. It’s debatable whether these chemicals act similarly in humans. But there is evidence that smelling these odors can affect the mood and physiological state of both men and women. We have a lot more studying to do, but this finding and others in the future will create a picture of how smell may relate to sexual reproduction.”

Matsunami added that there are likely other receptors and receptor variants that may also play roles in how these two chemicals are perceived. Because there are about 400 specific smell receptors and humans can detect more than 10,000 different odors, different combinations of receptor genes and variants must be involved in perceiving each odor, Matsunami said.

Duke University

GRAVESTONES TALKING THROUGH TIME

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A visit to your local graveyard can provide not only a history lesson, but a science lesson as well. Historians know that gravestones can reflect the lives of people whose memories are lost in time, and they have long scoured old burial sites to piece together the stories of those who rest there.

But today scientists are learning much more from those letters carved in stone. Gravestones are telling the story of changes in Earth’s atmospheric chemistry and rainfall. Moreover, scientists are asking for your help to read the stones.

The iconic white marble headstones found in most graveyards around the world are wonderful diaries of changes in the atmosphere. Chemical interactions occur between the marble and the atmosphere over time. Little by little, atmospheric gases dissolved in rain drops cause the marble to erode. Changes in atmospheric chemistry also change the rate at which the marble weathers.

By accumulating volunteers' measurements of marble gravestones of different ages around the world, scientists hope to produce a world map of the weathering rates of those gravestones and thereby deduce how the atmosphere has been changing.

Participants are asked to take measurements using simple calipers and GPS, following a set of scientific protocols that are explained online. Data is then logged by participants directly into the scientific database via the project Web site.

The project is part of the new global citizen science program called EarthTrek, which is administered by The Geological Society of America in partnership with organizations across America and around the globe. People interested in participating can register online and follow links to the Gravestone Project or any of several other scientific research projects currently underway through the EarthTrek program.

"Being involved in EarthTrek provides people with the opportunity to be involved in real scientific research," says Gary Lewis, EarthTrek Director.

"The data they collect while participating in a wonderful outdoor activity may make a real difference in the way we manage our environment. And it's free to participate!"

Not only can participants be involved first-hand in scientific research, they can also accumulate points for online rewards and other recognition. EarthTrek can become an obsession --enthusiasts sometimes plan weekend trips to collect gravestone data or engage in other EarthTrek activities. Other current studies involve spotting hummingbirds and investigating invasive plant species.

More projects are soon to be added. "We are working with scientists on new projects involving hail, natural springs, animal and plant inventories, and much more," Lewis says.

(Photo: GSA)

The Geological Society of America

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