Friday, May 21, 2010

ODD MOSAIC OF DENTAL FEATURES REVEALS UNDOCUMENTED PRIMATE

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It's in the teeth. An odd mosaic of dental features recently unearthed in northern Egypt reveals a previously undocumented, highly-specialized primate called Nosmips aenigmaticus that lived in Africa nearly 37 million years ago.

Because it is only known from its teeth, the paleontologists who discovered it don't know what its body looked like, but the find likely represents an ancient African lineage whose discovery makes early primate evolution on that continent more complicated.

"It comes as a bit of a shock to find a primate that defies classification," said lead researcher and assistant professor of Anatomical Sciences Erik Seiffert of New York's Stony Brook University.

Seiffert says during the last 30 years or so, three major primate groups were established as being present in Africa some 55 to 34 million years ago: early monkeys, lemur-like primates, and an extinct group called adapiforms. But the newly discovered primate's teeth place Nosmips in Africa at the same time. What's more, its teeth suggest it could be an evolutionary oddity that is not closely related to any of these groups.

Nosmips' discoverers report the finding in this week's Proceedings of the National Academy of Sciences. The National Science Foundation supported the research.

"When you find the teeth of a fossil primate, it's usually pretty clear where it fits into the family tree," said Seiffert. "There are only a few species that nobody agrees about and that really can't be placed into any of the major primate groups. These mystery fossils must have something important to tell us about primate evolution."

Right now Nosmips is one of those rare mystery fossils and so far is only known by 12 teeth, most of which were found in isolation at a site in the Fayum Depression about 40 miles outside Cairo, Egypt. The discoveries result from work during several field seasons over nine years.

Paleontologists usually identify primate fossils by their teeth because teeth are the most durable parts of the body and are most likely to fossilize, and so are most likely to be recovered.

"We were lucky to find even two teeth of Nosmips in each field season over the course of the nine years," said Seiffert. "That amounts to over nine months of continuous work. Only through working over such a long time span were we able to piece together the arrangement of Nosmips' teeth."

Analysis shows Nosmips had a rare combination of enlarged and elongated premolars with simple upper molars. It also had premolar teeth that had taken on the form of molars, instead of being relatively simple as in most other primates.

"Nosmips appears to be a highly specialized member of a previously undocumented and presumably quite ancient endemic African primate lineage" Seiffert said.

The researchers note that Nosmips lived alongside another specialized primate named Afradapis, which the same team described last year in a paper in the journal Nature. Seiffert and colleagues compared the teeth of these extinct species with those of living primates, and determined that Afradapis had adaptations for eating leaves, whereas Nosmips probably ate more fruits and insects.

"As time goes on and more discoveries are made, it will be fascinating to see how different lineages contributed to primate diversity in the Eocene of Africa," Seiffert said.

(Photo: Erik Seiffert, Stony Brook University)

National Science Foundation

HOT NEW MATERIAL CAN KEEP ELECTRONICS COOL

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Professor Alexander Balandin and a team of UC Riverside researchers, including Chun Ning Lau, an associate professor of physics, have taken another step toward new technology that could keep laptops and other electronic devices from overheating.

Balandin, a professor of electrical engineering in the Bourns College of Engineering, experimentally showed in 2008 that graphene, a recently discovered single-atom-thick carbon crystal, is a strong heat conductor. The problem for practical applications was that it is difficult to produce large, high quality single atomic layers of the material.

Now, in a paper published in Nature Materials, Balandin and co-workers found that multiple layers of graphene, which are easier to make, retain the strong heat conducting properties.

That's also a significant discovery in fundamental physics. Balandin's group, in addition to measurements, explained theoretically how the materials' ability to conduct heat evolves when one goes from conventional three-dimensional bulk materials to two-dimensional atomically-thin films, such as graphene.

The results published in Nature Materials may have important practical applications in removal of dissipated hear from electronic devices.

Heat is an unavoidable by-product when operating electronic devices. Electronic circuits contain many sources of heat, including millions of transistors and interconnecting wiring. In the past, bigger and bigger fans have been used to keep computer chips cool, which improved performance and extended their life span. However, as computers have become faster and gadgets have gotten smaller and more portable the big-fan solution no longer works.

New approaches to managing heat in electronics include incorporating materials with superior thermal properties, such as graphene, into silicon computer chips. In addition, proposed three-dimension electronics, which use vertical integration of computer chips, would depend on heat removal even more, Balandin said.

Silicon, the most common electronic material, has good electronic properties but not so good thermal properties, particularly when structured at the nanometer scale, Balandin said. As Balandin's research shows, graphene has excellent thermal properties in addition to unique electronic characteristics.

"Graphene is one of the hottest materials right now," said Balandin, who is also chair of the Material Sciences and Engineering program. "Everyone is talking about it."

Graphene is not a replacement for silicon, but, instead could be used in conjunction with silicon, Balandin said. At this point, there is no reliable way to synthesize large quantities of graphene. However, progress is being made and it could be possible in a year or two, Balandin said.

Initially, graphene would likely be used in some niche applications such as thermal interface materials for chip packaging or transparent electrodes in photovoltaic solar cells, Balandin said. But, in five years, he said, it could be used with silicon in computer chips, for example as interconnect wiring or heat spreaders. It may also find applications in ultra-fast transistors for radio frequency communications. Low-noise graphene transistors have already been demonstrated in Balandin's lab.

(Photo: UCR)

UC Riverside

GOCE SATELLITE DETERMINES GRAVITATIONAL FORCE IN THE HIMALAYAS

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ESA's GOCE satellite has been orbiting the Earth for more than a year and surveying its gravitational field more accurately than any instrument previously. The goal of the researchers – including scientists at the Technische Universitaet Muenchen (TUM) – is to determine the gravitational force in precise detail even in pathless places like the Himalayas. Evaluations of the first data from the satellite indicate that current models of the gravitational field in some regions can be fundamentally revised. On that basis, researchers expect to develop a better understanding of many geophysical processes, including for example earthquakes and ocean circulation. Another success: The satellite will probably manage to work in space for a much longer period than intended.

Gravitation is one of the fundamental forces of nature, but it is by no means the same everywhere. Earth's rotation, height differences of the surface, and the composition of the crust cause significant differences in the global gravitational field. Measuring the field with previously unattainable precision – thereby contributing to the understanding of its effects – is the task of GOCE (Gravity Field and Steady-State Ocean Circulation Explorer), which lifted into earth's orbit on March 17, 2009. In addition, GOCE is expected to provide the basis for the most accurate calculation of the "geoid" possible. Geoid is the name given to the virtual sea level of a global ocean at rest, which is used, for example, as a height reference for construction projects.

In recent months, researchers from the GOCE Gravity Consortium, a group of ten European institutes from seven countries, have processed data from the satellite in such a way that it can be used for model calculations. They can already see that GOCE will enable significant progress to be made in mapping. "It is becoming clear that we are receiving good information for the regions that are of interest from a geophysical point of view," says TUM geodesist Prof. Reiner Rummel, chairman of the consortium, who presented the first interim results of the mission on May 7 at the General Assembly of the European Geosciences Union in Vienna.

The scientists had suspected that there were large inaccuracies in the previous models, calculated on the basis of conventional methods, particularly in the Himalayas, parts of Africa, and the Andes The initial evaluations of the GOCE data do indeed confirm this hypothesis. "Measurements made from the surface of the Earth in regions that are difficult to get to carry a high risk of errors," explains Rummel. "This is not a problem for the satellite, of course."

Not only the data, but also the satellite itself is proving to be very robust. It was originally intended to carry out the actual measurements for one year from October, with a break after six months. However, GOCE's energy supply is operating so well and its stability is so high that this rest phase was not necessary. "We hope we can continue to measure for even three to four years," says Rummel - and this despite the extremely challenging track the satellite is on: Its working height of 255 kilometers is the lowest Earth orbit ever for a scientific satellite. Its path must be continuously corrected with an electric ion propulsion system so that it does not crash to Earth. "This works extremely well," says Rummel with delight. The Sun, which has been behaving extremely peacefully in recent months, is aiding the mission. Stronger solar activity would increase the aerodynamic drag and thus make control more difficult.

The scientists expect the mission to enable better understanding of many processes both on and below the surface of the Earth. Because gravitation is directly correlated with the distribution of mass in the Earth's interior, mapping gravitation in detail can contribute to better understanding of dynamics in Earth's crust. Understanding better why and where the movement of tectonic plates causes earthquakes is of great significance, particularly for regions on plate boundaries such as the Himalayas and the Andes. The researchers hope that the mission could eventually contribute to development of an early warning system for earthquakes.

With the aid of the new data, scientists also want to measure ocean circulation globally, precisely, and in detail for the first time. The ability to measure changes to ocean circulation and sea level is crucial for all global climate studies. Until now, ocean circulation has mainly been derived from mathematical model calculations.

Surveying should also profit enormously from the GOCE data. The exact reference planes can be used to correctly compare the heights of the Earth's surface on different continents. Through coordination with measurements from satellite navigation systems (e.g. GPS or GALILEO), it will be possible in the future to make such data available with centimeter accuracy to every user. And last but not least, it also will become simpler to plan the construction of roads, tunnels, and bridges.

The consortium scientists, coordinated at the TU Muenchen, will now use the pre-processed data to develop an initial global model of the gravitational field. It will be presented at the Living Planet Symposium of the European Space Agency ESA at the end of June in Bergen, Norway.

(Photo: ESA)

Technische Universitaet Muenchen

RESEARCHERS PIN DOWN THE ELUSIVE MASSES OF UP, DOWN AND STRANGE QUARKS

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Quarks, the elementary particles that make up protons and neutrons, have been notoriously difficult to nail down -- much less weigh -- until now. A research group co-founded by Cornell physics professor G. Peter Lepage has calculated, with a razor-thin margin of error, the mass of the three lightest and, therefore, most elusive quarks: up, down and strange.

The work of Lepage, the Harold Tanner Dean of the College of Arts and Sciences, and collaborators from several international institutions, is published online (March 31) and in print in Physical Review Letters (Vol. 104:13).

The findings reduce the uncertainty of the quark masses by 10 to 20 times down to a few percent. Scientists have known the mass of a proton for almost a century, but getting the mass of the individual quarks inside has been an ongoing challenge. The quarks are held together by the so-called strong force -- so powerful that it's impossible to separate and study them. They exist in a soup of other quarks, antiquarks and gluons, which are another type of particle.

To determine the quark masses, Lepage explained, it was necessary to fully understand the strong force. They tackled the problem with large supercomputers that allowed them to simulate the behavior of quarks and gluons inside such particles as protons.

Quarks have an astonishingly wide range of masses. The lightest is the up quark, which is 470 times lighter than a proton. The heaviest, the t quark, is 180 times heavier than a proton -- or almost as heavy as an entire atom of lead.

"So why these huge ratios between masses? This is one of the big mysteries in theoretical physics right now," Lepage said. "Indeed it is unclear why quarks have mass at all." He added that the new Large Hadron Collider in Geneva was built to address this question.

According to their results, the up quark weighs approximately 2 mega electron volts (MeV), which is a unit of energy, the down quark weighs approximately 4.8 MeV, and the strange quark weighs in at about 92 MeV.

(Photo: Christine Davies/University of Glasgow)

Cornell University

MAKING ROOM FOR MUSHROOMS

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With a reputation as being poisonous, at worst, or just plain icky at best, the humble mushroom should get some serious credit as a health food, say University of Alberta nutrition students.

"We were surprised to discover that fresh mushrooms provide much more of a health benefit than we originally expected," said Kaila Hauck, one of four science and nutrition undergraduate students in the Department of Agricultural, Food and Nutritional Science who reviewed existing research literature on the topic for a year-end capstone course project.

After combing through more than 60 scientific papers detailing the compounds of edible mushrooms, Hauck and her classmates were amazed at the array of benefits the fungi have for fending off cancer, fighting viruses and reducing inflammation in the body.

"I had no idea mushrooms had any health benefit at all, let alone several," added Hauck's classmate, Erika Janisch.

Fungi weren't at the top of Janisch's menu when she began working on the project, but she changed her mind as she got deeper into the work.

"Throughout our research we kept finding more facts on mushrooms that made me think I should be eating more of these. I never liked the taste or the texture, but when you cook them, they absorb many flavours of the foods they are cooked with. This helped me work them into my diet.

"If it weren't for this project, I wouldn't know about the health benefits of mushrooms and I would continue to look at them with disgust."

Mushrooms served as a food source for prehistoric humans. Throughout history, they've been valued by various cultures for their medicinal qualities. There are between 700 and 2,000 known species.

"One of the most significant health benefits is the potential role played in inhibiting different types of cancer tumours," said Hauck. "The World Cancer Report is predicting 15 million new cases of cancer by the year 2020, and while this is alarming, there is evidence that proper nutrition can prevent as many as one third of cancers worldwide." The beta-glucans found in the mushroom can play a role in cancer prevention, as can other helpful compounds, such as selenium, Hauck said.

"In fact, mushrooms provide more selenium than any other fruit or vegetable," which is a compound believed to decrease the incidence of some human cancers. Selenium is also being used along with chemotherapy in clinical trials, resulting in enhanced therapeutic effects, Hauck added.

In addition, the studies show that mushrooms contain antioxidants, which help reduce the risk of heart disease and other chronic illnesses.

Though mushrooms were considered to be an oddball research project at first, Hauck and Janisch are pleased their investigation provided a heaping helping of experience, along with a newfound respect for mushroom burgers.

"It fascinated me that with a bit of research you can learn so much, more than studying for an exam," said Janisch, who, equipped with both theory and practice, now feels ready to enter the work world. "Research sticks with you and [a capstone project] is a great way to pull everything together that you've learned in four years of school."

"Projects like this are a good way for students to learn about issues pertinent to the food industry, and to get a first taste of research," added Lingyun Chen, an assistant professor of plant protein and chemistry in the Department of Agricultural, Food and Nutritional Science who supervised the students.

"Because it's a fungi, people may be squeamish about eating mushrooms, but they are definitely a superstar in the food world," Hauck said.

University of Alberta

DIAGNOSING HEART ATTACKS MAY BE A LICK AND A CLICK AWAY

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A diagnostic tool developed by Rice University scientists to detect heart attacks using a person's saliva is being tested at the Michael E. DeBakey VA Medical Center (MEDVAMC) in collaboration with Baylor College of Medicine (BCM) in Houston.

John T. McDevitt, professor of chemistry and bioengineering at Rice, and his team of researchers at Rice's BioScience Research Collaborative have developed a microchip sensor, the Nano-Bio-Chip, which processes saliva and yields on-the-spot results. McDevitt intends to establish Houston as the hub of a biomarker highway where Nano-Bio-Chips will be configured to diagnose a variety of diseases.

"The device works by analyzing saliva, looking for cardiac biomarkers of injury implicated in the heart attack," said Dr. Biykem Bozkurt, professor of medicine at BCM.

"We find salivary tests, when combined with electrocardiograms (ECG), can provide more accurate information than the ECG alone for patients with chest pain," McDevitt said. "Saliva-based tests have the potential to quickly diagnose heart-attack victims as well as to find false alarms."

Typically, when a heart attack occurs, emergency medical technicians or hospital staff use an ECG machine to review heart activity. If the ECG is abnormal, the patient is immediately moved to an area to be treated. Unfortunately, ECGs fail to correctly diagnose about a third of patients having a heart attack. These patients are monitored carefully in the emergency room, where further blood tests are used to look for certain biomarkers to verify whether a heart attack has occurred.

"At the DeBakey VA, we follow this same procedure but also include the saliva test to determine whether salivary biomarkers will perform similar to blood markers in diagnosing a heart attack," said Bozkurt, who is also chief of cardiology at the MEDVAMC. "The patients presenting with chest pain are enrolled from the VA emergency room after informed consent and provide a saliva swab as well as blood samples. It is anticipated that saliva will be an alternative or complementary technique to blood drawing for early diagnosis of heart attacks, ultimately for testing in the ambulance before arrival in the emergency room."

Over the next two years, samples from approximately 500 patients who come to the MEDVAMC emergency room with chest pain or heart attack-related symptoms will be collected.

To obtain a saliva sample for the Nano-Bio-Chip, health care providers swab a patient's gums with a cotton-tipped stick. The saliva is transferred to the disposable diagnostic microchip. The microchip is then inserted into an analyzer and within a few minutes the saliva sample is checked and results delivered.

Nano-Bio-Chips deliver all the capabilities of a traditional laboratory but do not require expensive instrumentation to get results. Manufactured with techniques pioneered by the microelectronics industry, they have the potential to analyze large amounts of biomarker data at significantly lower cost than traditional tests, McDevitt said.

Chest pain brings about 5 million patients to U.S. emergency rooms each year, but 80 percent of those patients are not suffering heart attacks. Blood test results can take anywhere from 90 minutes to three hours, and in many cases it may be 12 to 24 hours before patients know whether or not they had a heart attack.

McDevitt said the new test could save lives, time and money by allowing doctors to identify those suffering from a heart attack before administering a battery of costly tests. "We hope to bend down U.S. health care costs through the marriage of electronics with diagnostic devices," he said.

"We believe that, in the future, we may be able to apply the same technology to improve screening for cardiovascular disease and diabetes, to identify problems before someone gets a heart attack," said Dr. Christie Ballantyne, chief of atherosclerosis and vascular medicine and professor of medicine at BCM and director of the Center for Cardiovascular Disease Prevention at the Methodist DeBakey Heart and Vascular Center.

Rice University

NEW 'METAMATERIAL' DEVICE MAY LEAD TO SEE-THROUGH CAMERAS AND SCANNERS

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Devices that can mimic Superman's X-ray vision and see through clothing, walls or human flesh are the stuff of comic book fantasy, but a group of scientists at Boston University (BU) has taken a step toward making such futuristic devices a reality.

Led by BU's Richard Averitt, the team has developed a new way to detect and control terahertz (THz) radiation using optics and materials science. This type of radiation is made up of electromagnetic waves that can pass through materials safely. Their work may pave the way for safer medical and security scanners, new communication devices, and more sensitive chemical detectors.

Scientists and engineers have long sought devices that could control THz transmissions. Such a device would be a technological breakthrough because it would allow information to be sent via THz waves. Like X-rays, these waves can pass through solid materials, potentially revealing hidden details within. Unlike the ionizing energy of real X-rays, THz radiation causes no damage to materials as it passes through them.

The quest to create devices that emit or manipulate THz radiation is often referred to as a race to fill in the "THz gap," since the frequency of THz radiation on the electromagnetic spectrum falls in between microwave and infrared radiation -- both of which are already broadly used in communication.

This race has often stumbled right out of the blocks, however, because no technologies have proven able to effectively solve the basic problem of manipulating the properties of a beam of THz radiation. Now Averitt and his colleagues have made an important step in this direction by using an unusual class of new materials known as "metamaterials."

Metamaterials are unusual in the way they interact with light, giving them properties that don't exist in natural materials. They have grabbed headlines and captured the popular imagination in recent years after several groups of researchers have used metamaterials to achieve limited forms of "cloaking" -- the ability of a material to completely bend light around itself so as to appear invisible.

Averitt uses these same sorts of metamaterials to interact with and change the intensity of a beam of THz radiation. His device consists of an array of split-ring-resonators -- a checkerboard of flexible metamaterial panels that can bend and tilt. By rotating the panels, his team can control the electromagnetic properties of a beam of THz energy passing by them.

"The idea is that you can manipulate your terahertz beam by reorienting the metamaterial elements as opposed to reorienting your beam," says Averitt.

Arrays of these metamaterial panels could potentially function as pixels on a camera that detects THz radiation, he says. Absorption of THz radiation would cause the panels to tilt more or less depending on the intensity of the THz bombarding them.

"One of the goals, from a technological point of view, is to be able to do stand-off imaging, to be able to detect things beneath a person's clothes or in a package," says Averitt.

Such detection applications, though, would require more powerful THz sources like quantum cascade lasers, which are under development -- though great technological strides have been made in the last few years.

The Optical Society

COATING APPROACH CLEARS UP FINGERPRINTS

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CSI notwithstanding, forensics experts cannot always retrieve fingerprints from objects, but a conformal coating process developed by Penn State professors can reveal hard-to-develop fingerprints on nonporous surfaces without altering the chemistry of the print.

"As prints dry or age, the common techniques used to develop latent fingerprints, such as dusting or cyanoacrylate -- SuperGlue -- fuming often fail," said Robert Shaler, professor of biochemistry and molecular biology and director of Penn State's forensic sciences program.

This happens because most of the techniques currently used for developing fingerprints rely on the chemistry of the print. Fingerprints are made up of a mixture of secretions from the body that reacts with different chemicals to form a visible or fluorescent product. Infrared and x-ray imaging also target specific chemicals left behind by the ridges and valleys in the skin.

"Lots and lots of processes take advantage of the chemistry of fingerprints," said Shaler. "This approach looks at the geometry of the fingerprints."

The conformal coating applications suggested by Shaler and Akhlesh Lakhtakia, Charles Godfrey Binder Professor in engineering science and mechanics, use the physical properties of the fingerprint, not the chemistry of the substances left behind. In fact, the researchers believe that even after the fingerprints are developed using the coating, forensics experts could sample the fingerprint material to determine specifics about the person who left the prints.

"The body chemistry of the person who left the fingerprint can tell us some things," said Shaler. "If the suspect is older or younger or a lactating mother, for example."

The researchers used a form of physical vapor deposition -- a method that uses a vacuum and allows vaporized materials to condense on a surface creating a thin film. Normally, the deposition process requires exceptionally clean surfaces because any speck of dust or grease on the coated surface shows up as a deformity. However, with fingerprints, the point is to have the surface material's ridges and valleys -- topography -- show up on the new surface so analysts can read them using an optical device without the necessity of chemical development or microscopy.

"This approach allows us to look at the topography better and to look at the chemistry later," said Shaler. "We wouldn't have thought of this by ourselves, but we could do it together."

One benefit of this approach would be the ability to retrieve fingerprints off fragments from incendiary or explosive devices and still be able to analyze the chemicals used in the device.

The specific method used is a conformal-evaporated-film-by-rotation technique developed to create highly accurate copies of biological templates such as insect eyes or butterfly wings. Both are surfaces that have nanoscale variations.

"It is a very simple process," said Lakhtakia. "And fingerprints are not nanoscale objects, so the conformal coating is applied to something big by nanotechnology standards."

The researchers tested two materials for coating, magnesium flouride and chalcogenide glass -- a combination of germanium, antimony and selenium. The coating material is heated in a vacuum, while the artifact to be coated is rotated fairly quickly to allow deposition over the entire surface.

"We need to have a coating that is uniform as far as we can see," said Lakhtakia. "But we do not need much of a coating -- in the range of only a micron."

The researchers tried coating a variety of fingerprints on glass and even on tape. They coated pristine fingerprints and those that had been fumed with SuperGlue. In all cases, the coated fingerprints were usable.

Of course, like all approaches, this one can only be used on non-porous surfaces, surfaces that do not de-gas. The equipment used to deposit the coating is a laboratory device, but it can produce the coating in about 15 minutes. The researchers would like to design a portable device that could be brought to a crime scene and produce readable fingerprints on site.

"We are in the process of redesigning the chamber and looking not just at fingerprints, but at other objects," said Lakhtakia. "These would include bullets, cartridges, footprints, bite marks and lip impressions." Shaler and Lakhtakia have filed a provisional patent application on this application.

(Photo: publicsafety.utah.gov)

The Pennsylvania State University

DINOSAUR RESEARCH: CHEW AND STAY SMALL

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There is a simple rule of thumb. The larger an animal is, the more time it spends eating. This means an elephant hardly has time to sleep. It spends 18 hours every day satisfying its huge appetite. 'This led us to one of the many riddles that gigantism of dinosaurs puts before us,' Professor Martin Sander from the University of Bonn explains. 'They were just so large that a day would have had to have 30 hours so that they were able to meet their energy demands.'

Martin Sander is a spokesman for an international research group which is looking for explanations for this and other paradoxes. The Deutsche Forschungsgemeinschaft (German Research Foundation) has funded the project to date with three million euros. Now the scientists involved have presented the fruits of their work on more than 30 pages in the 'Biological Reviews'. For the first time, their research is offering a plausible answer to the question which the group sought to answer six years ago: why the giant long-neck dinosaurs were even able to exist. The researchers also explain why today's terrestrial animals are nowhere near reaching the Jurassic size record. One reason is that we chew. Giant dinosaurs gulped.

Chewing helps to digest the food faster. By the grinding process it is broken down and at the same time its surface is enlarged. This way the digestive enzymes are able to attack the food more easily. 'Chewing is a property of prototheria which no large herbivorous terrestrial mammal has got rid of,' Martin Sander says. But chewing requires time – a resource that becomes scarce with increasing size. At the same time the following is true: the ones that chew need a large head, since molars and muscles have to be put somewhere. Not without reason elephants are quite big-headed.

However, the herbivorous giant dinosaurs had relatively small, light skulls. Only this fact enabled them to grow extremely long necks. And these again helped them to make food intake as efficient as possible. So they did not constantly have to heave their 80-ton body over the Jurassic savanna while looking for their greens. They just remained on the spot and used their agile neck to browse their surroundings. This was particularly relevant for the heavy-weights. Smaller dinos simply had far smaller necks compared to their body length.

Horsetails were part of the sauropods' diet. For, according to research by the group, they are exceptionally nutritious. However, only a few animals feed off them today. A reason for this is presumably that horsetails are bad for the teeth. They contain a lot of silicate, which acts like sandpaper. But as long as you do not chew them but just pluck them and simply gulp them down, that is no big problem. Scientists from the US have recently discovered that sauropods renewed their teeth exceptionally often, some even in a monthly cycle.

The digestion process itself probably took several days with the giant dinosaurs, due to the missing molars. However, their stomachs were so large that they still provided them with enough energy round the clock. Moreover, the metabolism of these giant animals was incredibly powerful. They possessed amazingly sophisticated lungs, which were far more effective than those of humans. The large number of air sacs which permeated the body cavity and vertebra of the dinosaurs played an important role in their function. Combined with a nifty system of valves they ensured that a gas exchange could take place while breathing in as well as while breathing out. A nice side effect was that the neck got significantly lighter this way. This was important for the statics of the animals.

'In the history of species the lungs of today's birds and of the giant dinosaurs have the same origin,' Martin Sander says. 'This effective air exchange principle was invented about 230 million years ago.' This is consistent with the fact that the earth passed through an oxygen trough at the time. The concentration only 12 to 15 per cent, i.e. a third less than today. So being able to pick out the few oxygen molecules in the thin air as rapidly and well as possible was a huge advantage.

In their article the scientists also deal in detail with further factors, without which the huge herbivores would not have existed. These are inter alia the high reproduction rate which enabled animals even to survive under adverse conditions. As Martin Sander says: '200 million years ago, an unparalleled combination developed of primitive traits, which were new in the history of evolution. This combination made these fascinating giants possible.'

(Photo: Frank Luerweg, Universität Bonn)

University of Bonn

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