Thursday, June 17, 2010


0 comentarios
University of Alaska Fairbanks scientist Michael Whalen is part of a team of distinguished scientists who recently compiled a wide swath of evidence striking a definitive blow in the ongoing battle over what killed the dinosaurs.

In a review published in the March 5 issue of the journal Science, the research group reaffirmed the recently challenged theory that an asteroid ended the age of the dinosaurs.

Scientists first proposed the asteroid impact theory of dinosaur mass extinction 30 years ago. The discovery of a massive crater at Chicxulub [CHICK-shuh-loob], in Mexico’s Yucatán Peninsula in 1991, strengthened that hypothesis. The Chicxulub crater is more than 120 miles wide--about the distance from Fairbanks to the Arctic Circle--and scientists believe it was created when an asteroid more than six miles wide crashed into Earth 65 million years ago. The cataclysmic impact--a million times more powerful than the largest nuclear bomb ever tested--triggered massive earthquakes, atmospheric discharge and oceanic upheaval. The ensuing mass extinction ended both the reign of the dinosaurs and the Cretaceous period, which gave way to the Paleogene period. This theory, having steadily accumulated evidence, was thought to be a near-consensus view.

Recently, however, in a series of articles, researchers posed an alternate hypothesis for the mass extinction. Some scientists claim that long-term volcanic activity at the Deccan Traps, in what is now India, caused acid rain and global cooling, gradually making life untenable for the dinosaurs and other large animals. They also suggest that the Chicxulub impact occurred some 300,000 years before the mass extinctions.

The alternate hypothesis spurred Whalen and other Chicxulub impact proponents to respond. The current Science article dispels the Deccan Traps hypothesis, arguing that the geological record favors the Chicxulub impact event theory.

“It’s as tight a case for a synchronous chain of events as we can find in the fossil record,” Whalen said.

Whalen is an associate professor at the UAF geology and geophysics department and the Geophysical Institute. He first began studying the Chicxulub site in 2002. His expertise is in carbonate rock, or limestone--a handy specialty, as limestone forms the layers above the Cretaceous-Paleogene geological boundary in the Chicxulub crater. He studied a 2001 core from the crater and compared it to seismic data gathered in 2006. His analysis offered insight on the geography of the area prior to impact, how it changed during the impact and the eventual infill of the crater by limestones deposited after the impact event.

University of Alaska Fairbanks


0 comentarios

A compound found in sunless tanning spray may help to heal wounds following surgery, according to a study by Cornell biomedical engineers and plastic surgeons at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

Results published online May 31 in Proceedings of the National Academy of Sciences show that a sticky gel of polyethylene glycol and a polycarbonate of dihydroxyacetone (MPEG-pDHA) may help to seal surgical wounds.

Procedures to remove cancerous breast tissue, for example, often leave a hollow space that fills with seroma fluid and must typically be drained by a temporary implant. "This is an unpleasant side effect of surgery that is often unavoidable," said co-author Dr. Jason Spector, a plastic surgeon at NewYork-Presbyterian Hospital/Weill Cornell Medical Center."The new substance would act to glue together the hole left behind to prevent seroma buildup."

DHA sticks to certain compounds (amines) in biological tissues. Its sticky properties allow sunless tanners to adhere to the skin without being wiped off. Because it is biodegradable and water soluble, DHA does not stay tacked onto the body's tissues forever. Currently used "bio-glues" are made from animal products and take a long time to degrade in the body -- factors that raise the risk of infection.

"DHA is a compound that is naturally produced in the body," said lead author David Putnam, associate professor of biomedical engineering on Cornell's Ithaca campus. "The glue is broken down, or metabolized, and then safely removed by the body."

Putnam's lab has worked to create safe, synthetic compounds from chemicals found in nature. DHA is an intermediary compound produced during the metabolism of glucose, a sugar used by the body for fuel.

To create MPEG-pDHA, Putnam and colleagues first bound the single molecule monomer of DHA, which is highly reactive, to a protecting group molecule, making it stable enough to manipulate. This allowed the engineers to bind the monomers together to form a polymer, or chain of molecules, along with MPEG. Doing so allows the polymer gel to be injected through a syringe.

"Making a polymer from DHA has eluded chemical engineers for about 20 years," Putnam said.

Now in gel form, the compound has the ability to stick tissues together like an internal Band-Aid, preventing the pocket from filling with seroma fluid, Putnam said. The researchers found that the gel prevented or significantly lowered fluid buildup in rats that had had breast tissue removed.

"The next step would be to test the gel on larger animals and then in clinical trials in human surgical cases," Spector said.

Previous results published by Putnam and Spector in the August 2009 issue of the Journal of Biomedical Materials Research showed that the gel also prevented bleeding in a rat liver.

"This is another aspect of the compound that would be greatly beneficial if proven to be applicable in humans," Spector said. "The gel could speed the healing and decrease bleeding within the body."

The work was supported in part by the National Science Foundation, the Morgan Tissue Engineering Fund, the Wallace H. Coulter Foundation and the New York State Center for Advanced Technology.

Other co-authors include Cornell's Peter Zawaneh, Weill Cornell's Sunil Singh and Peter Henderson and Robert Padera of Brigham and Women's Hospital.

(Photo: Cornell U.)

Cornell University


0 comentarios

A team of Duke University chemists has perfected a simple way to make tiny copper nanowires in quantity. The cheap conductors are small enough to be transparent, making them ideal for thin-film solar cells, flat-screen TVs and computers, and flexible displays.

"Imagine a foldable iPad," said Benjamin Wiley, an assistant professor of chemistry at Duke. His team reports its findings online this week in Advanced Materials.

Nanowires made of copper perform better than carbon nanotubes, and are much cheaper than silver nanowires, Wiley said.

The latest flat-panel TVs and computer screens produce images by an array of electronic pixels connected by a transparent conductive layer made from indium tin oxide (ITO). ITO is also used as a transparent electrode in thin-film solar cells.

But ITO has drawbacks: it is brittle, making it unsuitable for flexible screens; its production process is inefficient; and it is expensive and becoming more so because of increasing demand.

“If we are going to have these ubiquitous electronics and solar cells,” Wiley said, “we need to use materials that are abundant in the earth’s crust and don’t take much energy to extract.” He points out that there are very few materials that are known to be both transparent and conductive, which is why ITO is still being used despite its drawbacks.

However, Wiley’s new work shows that copper, which is a thousand times more abundant than indium, can be used to make a film of nanowires that is both transparent and conductive.

Silver nanowires also perform well as a transparent conductor, and Wiley contributed to a patent on the production of them as a graduate student. But silver, like indium, is rare and expensive. Other researchers have been trying to improve the performance of carbon nanotubes as a transparent conductor, but without much luck.

“The fact that copper nanowires are cheaper and work better makes them a very promising material to solve this problem,” Wiley said.

Wiley and his students, PhD candidate Aaron Rathmell and undergraduate Stephen Bergin, grew the copper nanowires in a water-based solution. “By adding different chemicals to the solution, you can control the assembly of atoms into different nanostructures,” Wiley said. In this case, when the copper crystallizes, it first forms tiny “seeds,” and then a single nanowire sprouts from each seed. It’s a mechanism of crystal growth that has never been observed before.

Because the process is water-based, and because copper nanowires are flexible, Wiley thinks the nanowires could be coated from solution in a roll-to-roll process, like newspaper printing, which would be much more efficient than the ITO production process.
Other researchers have produced copper nanowires before, but on a much smaller scale.

Wiley’s lab is also the first to demonstrate that copper nanowires perform well as a transparent conductor. He said the process will need to be scaled up for commercial use, and he’s got a couple of other problems to solve as well: preventing the nanowires from clumping, which reduces transparency, and preventing the copper from oxidizing, which decreases conductivity. Once the clumping problem has been worked out, Wiley believes the conductivity of the copper nanowires will match that of silver nanowires and ITO.

Wiley, who has applied for a patent for his process, expects to see copper nanowires in commercial use in the not-too-distant future. He notes that there is already investment financing available for the development of transparent conductors based on silver nanowires.

“We think that using a material that is a hundred times cheaper will be even more attractive to venture capitalists, electronic companies and solar companies who all need these transparent electrodes,” he said.

(Photo: Benjamin Wiley, Duke Chemistry)

Duke University


0 comentarios

Three thousand kilometres beneath our feet, the Earth's solid rock – known as the mantle – gives way to the swirling liquid iron of the outer core (the ‘core-mantle boundary’). The last few hundred kilometres of the lowermost mantle is also known as D” (pronounced ‘dee-double-prime’).

D” is one of the most enigmatic parts of the Earth which scientists have struggled to understand for decades; it can only be measured remotely, using seismic waves from earthquakes.

Geoscientists from the University of Bristol and University College London, report this week in the journal Nature that some of the poorly understood properties of D” might be explained by a sudden softening of the main mineral which makes up the mantle, due to the enormous pressures and temperatures near the Earth’s core.

By using supercomputers to make quantum mechanical simulations of the atoms which make up the mineral, the team show that a recently discovered change in its crystal structure makes it orders of magnitude weaker and therefore much easier to deform.

Dr James Wookey, an author on the paper from the University of Bristol's Department of Earth Sciences, said: "This softened mineral would allow the material in the lowermost mantle to flow much more easily along the surface of the iron core – rather like toothpaste being squeezed out of a tube. This zone of flow would have a profound effect on our understanding of the dynamic processes at work at the core-mantle interface."

The importance of the lowermost mantle stems from its role as an interface between two titanic convection systems within the Earth. The first is the rapid churning of liquid iron in the core: the engine which drives the Earth's magnetic field. The second is the much slower overturn of the solid mantle – the driving force for plate tectonics – which forms, shakes and eventually destroys the surface on which we live.

As a boundary for these convection systems, the lowermost mantle can profoundly affect their behaviour, so understanding it is vital for understanding the Earth’s long term evolution.

(Photo: Bristol U.)

University of Bristol


0 comentarios
Sound repetition allows us to memorize complex sounds in a very quick, effective and durable way. This form of auditory learning, which was evidenced for the first time by researchers from CNRS, ENS Paris, and Paris Descartes and Toulouse 3 universities, is believed to occur in daily life to help us identify and memorize sound patterns; it allows, for example, immediate recognition of sounds which become familiar through experience, such as the voice of relatives. The same mechanism is involved in the relearning of certain sounds, in particular when using hearing aids. This study, which has just been published in the journal Neuron, opens new perspectives for understanding the process of auditory memory.

“Until now, the only available data on acoustic memorization concerned simple sounds or language”, points out Daniel Pressnitzer, CNRS researcher at the Laboratoire psychologie de la perception (CNRS/Université Paris Descartes/ENS Paris). Three French researchers set themselves the challenge of addressing complex sounds and studying our ability to memorize them, as little was known on the subject.

In order to investigate how auditory memory is formed, the researchers subjected volunteers to various noise samples: these noises were generated in a totally random and unpredictable way to ensure that the volunteers would never have heard them before. Furthermore, these original complex sound waves had no meaning, and were perceived at first as an indistinct hiss. Listeners were not told that an identical complex noise pattern could be played several times during the experiment.

Using this fairly simple protocol, the scientists discovered that our ear is remarkably effective in detecting noise repetitions. Listeners nearly always recognized the noise pattern that had been played several times; two listenings were enough for those with a trained ear, and only about ten for less experienced ears. Sound repetition therefore induces both extremely rapid and effective learning, which occurs implicitly (it is not supervised). In addition, this memory for noise can last several weeks. A fortnight after the first experiment, volunteers identified the noise pattern again, at first attempt.

The scientists have demonstrated the existence of a form of fast, solid and long-lasting auditory learning. Their experimental protocol has proven to be a relevant and simple method that could make it possible to study auditory memory in both humans and animals. These results imply that a mechanism for rapid auditory plasticity – that is, a mechanism involved in an auditory neuron's ability to adapt its response to a given sound stimulant – plays a very effective role in the learning of sounds. This process is likely to be essential to identify and memorize recurrent sound patterns in our acoustic environment, such as the voice of relatives. It has all the characteristics considered necessary for human beings to learn to associate a sound with what produces it. The same mechanism may also be involved in relearning, which is often inevitable when hearing suddenly changes. This is true of hearing-impaired people who start using hearing aids. A period of adaptation to their prosthesis is necessary so they can get used to hearing sounds they no longer heard or perceived differently. The researchers hope that one day they will be able to study the effect of the modifications introduced by hearing aids on re-learning more in depth.



0 comentarios
Just because your mother has turned 85, you shouldn’t assume you’ll have to take over her financial matters. She may be just as good or better than you at making quick, sound, money-making decisions, according to researchers at Duke University.

“It’s not age, it’s cognition that makes the difference in decision-making,” said Scott Huettel, PhD, associate professor of psychology and neuroscience and director of the Duke Center for Neuroeconomic Studies. He recently led a laboratory study in which participants could gain or lose money based on their decisions.

“Once we accounted for cognitive abilities like memory and processing speed, age had nothing to do with predicting whether an individual would make the best economic decisions on the tasks we assigned,” Huettel said.

The study was published in the Psychology and Aging journal, published by the American Psychological Association.

Duke researchers assigned a variety of economic tasks that required different types of risky decisions, so that participants could gain or lose real money. They also tested subjects’ cognitive abilities -- including both how fast they could process new information and how well they could remember that information. They worked with 54 older adults between 66 and 76 years of age and 58 younger adults between 18 and 35 years of age.

The researchers used path analysis, a statistical method of finding cause-and-effect relationships, to determine whether age affected the economic decisions directly or whether it had indirect effects, such as age influencing memory, which in turn influenced decisions.

“The standard perspective is that age itself causes people to make more risky, lower-quality decisions -- independent of the cognitive changes associated with age,” said Huettel, who is also with the Duke-UNC Brain Imaging and Analysis Center. “But that isn’t what we found.”

The path analyses showed that age-related effects were apparently linked to individual differences in processing speed and memory. When those variables were included in the analysis, age was no longer a significant predictor of decision quality, Huettel said.

On a bell curve of performance, there was overlap between the younger and older groups. Many of the older subjects, aged 66 to 76, made similar decisions to many of the younger subjects (aged 18 to 35). “The stereotype of all older adults becoming more risk-averse is simply wrong,” Huettel said.

“Some of the older subjects we studied were able to make better decisions than younger subjects who scored lower on tests of their cognitive abilities,” Huettel said. “If I took 20 younger adults and 20 older adults, all of whom were above average on these measures, then on average, you could not tell them apart based on decisions. On the whole, it is true, more older people process slowly and has poorer memory. But there are also older people who do as well as younger people.”

Huettel said that the findings suggest strategies to assist people, such as allowing more time for decisions, or presenting data in certain ways to assist people in making decisions.

“Decision scaffolding is the concept that you can give people structure for decision-making that helps them,” Huettel said. “We should try to identify ways in which to present information to older adults that gives them scaffolding to make the best choices. If we can reduce the demand on memory or the need to process information very quickly that would be a great benefit to older adults and may push them toward making the same economically beneficial decisions as younger adults.”

In reality, younger adults more often work to obtain credit cards with lower interest rates and lower interest rates on mortgages, for example. Huettel said that using surveys that track real-world behavior might help to identify who would benefit from getting information in one manner versus another.

“Some younger adults, too, may benefit from getting their information in a slow, methodical way, while others may not,” Huettel said. “We may be able to predict that based on cognition.” Self-recognition is important, too, so that if someone knows they process things well over time, they might ask for more time to make a decision rather than making an impulsive decision on the spot, he added.

Duke University


0 comentarios

When the first warm rays of springtime sunshine trigger a burst of new plant growth, it’s almost as if someone flicked a switch to turn on the greenery and unleash a floral profusion of color. Opening a window into this process, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and collaborators at the University of Wisconsin, Madison, have deciphered the structure of a molecular “switch” much like the one plants use to sense light.

Their findings, described online in the Proceedings of the National Academy of Sciences the week of May 31, 2010, help explain how the switch works and could be used to design new ways to modify plant growth.

Previous studies showed that the light-sensing structure, called a phytochrome, exists in two stable states. Each state is sensitive to a slightly different wavelength, or color, of light — from red to “far red,” which is close to the invisible infrared end of the light spectrum. As the phytochrome absorbs photons of one wavelength or the other, it changes shape and sends signals that help plants know when to flower, produce chlorophyll, and grow.

“The phytochrome is almost like nature’s light switch,” said Brookhaven biophysicist Huilin Li, who is also an associate professor at Stony Brook University and a lead author on the study. “Finding out how this switch is flipped on or off by a signal as subtle as a single photon of light is fascinating.”

As with all biological molecules, one key to the phytochrome’s function is its structure. But scientists trying to get a molecular-level picture of a phytochrome have a formidable challenge: The phytochrome molecule is too dynamic to capture in a single image using techniques like x-ray crystallography. So, scientists have studied only the rigid and smaller pieces of the molecule, yielding detailed, but fragmented, information.

Now using additional imaging and computational techniques, the Brookhaven researchers and their collaborators have pieced together for the first time a detailed structure of a whole phytochrome.

Li and his collaborators studied a phytochrome from a common bacterium that is quite similar in biochemistry and function to those found in plants, but easier to isolate. Plant biologist Richard Vierstra of the University of Wisconsin provided the purified samples.

At Brookhaven, Li’s group used two imaging techniques. First, they applied a layer of heavy metal dye to the purified phytochrome molecules to make them more visible, and viewed them using an electron microscope. This produced many two-dimensional images from a variety of angles to give the researchers a rough outline of the phytochrome map.

The scientists also froze the molecules in solution to produce another set of images that would be free of artifacts from the staining technique. For this set of images, the scientists used a cryo-electron microscope.

Using computers to average the data from each technique and then combine the information, the scientists were able to construct a three-dimensional map of the full phytochrome structure. The scientists then fitted the previously determined detailed structures of phytochrome fragments into their newly derived 3-D map to build an atomic model for the whole phytochrome.

Though the scientists knew the phytochrome was composed of two “sister” units, forming a dimer, the new structure revealed a surprisingly long twisted area of contact between the two individual units, with a good deal of flexibility at the untwisted ends. The structure supports the idea that the absorption of light somehow adjusts the strength or orientation of the contact, and through a series of conformation changes, transmits a signal down the length of the molecular interface. The scientists confirmed the proposed structural changes during photo-conversion by mutagenesis and biochemical assay.

The scientists studied only the form of the phytochrome that is sensitive to red light. Next they plan to see how the structure changes after it absorbs red light to become sensitive to “far red” light. Comparing the two structures will help the scientists test their model of how the molecule changes shape to send signals in response to light.

(Photo: BNL)

Brookhaven National Laboratory


0 comentarios

Researchers on the OPERA experiment at the INFN1’s Gran Sasso laboratory in Italy announced the first direct observation of a tau particle in a muon neutrino beam sent through the Earth from CERN2, 730km away. This is a significant result, providing the final missing piece of a puzzle that has been challenging science since the 1960s, and giving tantalizing hints of new physics to come.

The neutrino puzzle began with a pioneering and ultimately Nobel Prize winning experiment conducted by US scientist Ray Davis beginning in the 1960s. He observed far fewer neutrinos arriving at the Earth from the Sun than solar models predicted: either solar models were wrong, or something was happening to the neutrinos on their way. A possible solution to the puzzle was provided in 1969 by the theorists Bruno Pontecorvo and Vladimir Gribov, who first suggested that chameleon-like oscillatory changes between different types of neutrinos could be responsible for the apparent neutrino deficit.

Several experiments since have observed the disappearance of muon-neutrinos, confirming the oscillation hypothesis, but until now no observations of the appearance of a tau-neutrino in a pure muon-neutrino beam have been observed: this is the first time that the neutrino chameleon has been caught in the act of changing from muon-type to tau-type.

Antonio Ereditato, Spokesperson of the OPERA collaboration described the development as: “an important result which rewards the entire OPERA collaboration for its years of commitment and which confirms that we have made sound experimental choices. We are confident that this first event will be followed by others that will fully demonstrate the appearance of neutrino oscillation”.

“The OPERA experiment has reached its first goal: the detection of a tau neutrino obtained from the transformation of a muon neutrino, which occurred during the journey from Geneva to the Gran Sasso Laboratory,” added Lucia Votano, Director Gran Sasso laboratories. “This important result comes after a decade of intense work performed by the Collaboration, with the support of the Laboratory, and it again confirms that LNGS is a leading laboratory in Astroparticle Physics”.

The OPERA result follows seven years of preparation and over three years of beam provided by CERN. During that time, billions of billions of muon-neutrinos have been sent from CERN to Gran Sasso, taking just 2.4 milliseconds to make the trip. The rarity of neutrino oscillation, coupled with the fact that neutrinos interact very weakly with matter makes this kind of experiment extremely subtle to conduct. CERN’s neutrino beam was first switched on in 2006, and since then researchers on the OPERA experiment have been carefully sifting their data for evidence of the appearance of tau particles, the telltale sign that a muon-neutrino has oscillated into a tau-neutrino. Patience of this kind is a virtue in particle physics research, as INFN President Roberto Petronzio explained:

“This success is due to the tenacity and inventiveness of the physicists of the international community, who designed a particle beam especially for this experiment,” said Petronzio. “In this way, the original design of Gran Sasso has been crowned with success. In fact, when constructed, the laboratories were oriented so that they could receive particle beams from CERN”.

At CERN, neutrinos are generated from collisions of an accelerated beam of protons with a target. When protons hit the target, particles called pions and kaons are produced. They quickly decay, giving rise to neutrinos. Unlike charged particles, neutrinos are not sensitive to the electromagnetic fields usually used by physicists to change the trajectories of particle beams. Neutrinos can pass through matter without interacting with it; they keep the same direction of motion they have from their birth. Hence, as soon as they are produced, they maintain a straight path, passing through the Earth's crust. For this reason, it is extremely important that from the very beginning the beam points exactly towards the laboratories at Gran Sasso.

“This is an important step for neutrino physics,” said CERN Director General Rolf Heuer. “My congratulations go to the OPERA experiment and the Gran Sasso Laboratories, as well as the accelerator departments at CERN. We’re all looking forward to unveiling the new physics this result presages.”

While closing a chapter on understanding the nature of neutrinos, the observation of neutrino oscillations is strong evidence for new physics. In the theories that physicists use to explain the behaviour of fundamental particles, which is known as the Standard Model, neutrinos have no mass. For neutrinos to be able to oscillate, however, they must have mass: something must be missing from the Standard Model. Despite its success in describing the particles that make up the visible Universe and their interactions, physicists have long known that there is much the Standard Model does not explain. One possibility is the existence of other, so-far unobserved types of neutrinos that could shed light on Dark Matter, which is believed to make up about a quarter of the Universe’s mass.

(Photo: CERN)



0 comentarios

A nutrient that’s common to all living things can make hibernating marmots hungry - a breakthrough that could help scientists understand human obesity and eating disorders, according to a new study by a Colorado State University biologist.

The study appears in the current issue of the Journal of Experimental Biology. The full paper is available at

Professor Greg Florant discovered he could slowly release a molecule called AICAR into yellow-bellied marmots that activates a neurological pathway driving food intake and stimulates appetite. The pathway, which shuts down during hibernation, relies on an important balance between two energy molecules – ATP and AMP. The lower the ratio between the two cellular molecules, the lower the energy in the cell and the more the appetite is stimulated.

Without this artificial stimulation, awake, hibernating marmots do not eat - even when researchers place food in front of them.

“The experimental group started to feed because they thought they had this energy deficit,” Florant said. “Then when the pumps dispensing the molecule finally stopped, the animals went right back into hibernation. That suggests to us that the animals are still sensing energy levels within cells during the hibernation period.”

Tissue samples taken from marmots in Florant's lab allow researchers to identify biochemical processes and genes that are active during hibernation - as opposed to genes that are active when they're feeding or engaging in other behaviors.

The American Physiological Society has called hibernators such as marmots, bears, woodchucks, hedgehogs and lemurs "medical marvels" because they can turn off their appetites and slow their breathing to a point that would be lethal to other animals.

Marmots typically hibernate for as many as six or seven months.

“You can’t eat if you’re asleep,” Florant said. “We’ve discovered that perhaps nutrients within the brain, such as fatty acids, can alter the food intake pathway, which normally shuts down when marmots hibernate. The perceived drop in energy nutrients (i.e. low ATP) makes the animals think they’ve got an energy deficit and want to eat.”

Florant said he’ll conduct additional research this summer to determine whether the reverse is true: Can he stop the animals from eating when they’re not hibernating?

His team will also identify neurons in the particular areas of the hypothalamus that are involved in food intake in animals. The hypothalamus is one of the master regulator areas of the brain and controls such activities as food intake, sex and temperature regulation.

“We know which neurons are driving this process,” he said. “We’re just trying to identify them within the marmot and distinguish what’s different about the neurons in a marmot compared to a rat or other animal that does not go into hibernation.”

(Photo: Colorado SU)

Colorado State University




Selected Science News. Copyright 2008 All Rights Reserved Revolution Two Church theme by Brian Gardner Converted into Blogger Template by Bloganol dot com