Jan 7, 2012
The findings were published in the Proceedings of the National Academy of Sciences and highlighted for their breakthrough in the long search for silk with such mechanical properties. The manuscript was published after an in-depth peer review process, and was deemed by the publishers as a newsworthy article of the issue in which it appears, further indicating its relative importance to science and technology.
"It's something nobody has done before," Fraser says. The project, which used Fraser's piggyBac vectors to create transgenic silkworms with both silkworm and spider silk proteins, was a collaboration of his laboratory with Donald Jarvis and Randolph Lewis at the University of Wyoming. Jarvis' lab made the transgene plasmids, while Fraser's lab made the transgenic silkworms and Lewis' lab analyzed the fiber from the silkworms. Results showed that the fibers were tougher than typical silkworm silk and as tough as dragline silk fibers produced by spiders, demonstrating that silkworms can be engineered to produce such improved fibers.
Commercial production of spider silk from spiders is impractical because spiders are too cannibalistic and territorial for farming. Researchers have experimented with producing the stronger material in other organisms, including bacteria, insects, mammals and plants, but those proteins require mechanical spinning -- a task the silkworms perform naturally. The stronger fiber could find application in sutures, where some natural silkworm silk is used, as well as wound dressings, artificial ligaments, tendons, tissue scaffolds, microcapsules, cosmetics and textiles.
This work is the culmination of a research effort begun more than 10 years ago with an internal award from Notre Dame to Fraser to develop silkworm transgenics capabilities; a two-year NIH R21 grant awarded to Jarvis, Lewis and Fraser; and several years of supplemental funding from Kraig BioCraft Laboratories. The success of this research would have been impossible without the ability to carry out silkworm transgenesis, mastered by Bong-hee Sohn and Young-soo Kim in the Fraser lab at Notre Dame.
Read more at Science Daily
They captured several mouse lemurs, measured them, took photos and small biopsies for genetic studies, and released them again. Prof. Ute Radespiel, Institute of Zoology of the University of Veterinary Medicine Hannover, analysed the samples and the morphological dataset, and confirmed that the animals from the Sahafina Forest belong to an undescribed species of the small nocturnal mouse lemurs.
„We were quite surprised by these findings. The Sahafina Forest is only 50km away from the Mantadia National Park in eastern Madagascar, which contains a different and much smaller species, the Goodman's mouse lemur," commented Prof. Radespiel. In contrast, the Gerp's mouse lemur belongs to the group of larger mouse lemurs, i.e. has a body mass of about 68g, and is therefore almost "a giant" compared to the Goodman's mouse lemur (ca. 44g body mass).
Read more at Science Daily
Jan 6, 2012
"We indeed may have observed the first evidence of the Higgs particle, but it is still too early for a definitive statement," says Professor Dr. Volker Büscher from the Institute of Physics at Johannes Gutenberg University Mainz (JGU) in Germany. "And if this evidence turns out to be correct, the data now being analyzed will for the first time provide information about the mass of the Higgs boson," adds Professor Dr. Stefan Tapprogge. At Mainz University, some 50 physicists participate in CERN's research, in particular in the ATLAS experiment, one of two major experiments tasked with searching for the Higgs particle.´
The particle was predicted almost 50 years ago and is named after the British physicist Peter Higgs. Since then, scientists all over the world have been searching for it. Its discovery would explain the origin of the masses of all other elementary particles. Just two years after its start, proton-proton collisions at the Large Hadron Collider (LHC) have now delivered the results which raise scientists' expectations. "At this point in time, we can make two statements," Büscher says. "First, if the Higgs boson actually has the characteristics it is assumed to have, then its mass must be between 115 and 131 gigaelectron volts -- a much smaller window than just a year ago. Second, we have found a very intriguing excess of events, which could be the first direct evidence of a Higgs boson with a mass around 125 GeV." The experiments at CERN will continue next year. If the evidence is confirmed, the Higgs boson would be about 125 times as heavy as a proton.
In addition to this new data from the ATLAS detector, the second large particle detector at LHC, the Compact Muon Solenoid (CMS), has revealed similar indications. Confirmation would be a dream come true for the scientists working with Volker Büscher and Stefan Tapprogge. Many have dedicated their academic careers to the hunt for the Higgs particle -- and are involved right now when things get really exciting. "This is a great moment for us all, and it would be wonderful if the observations were confirmed," says Tapprogge. Scientists are not yet speaking of a discovery, because it is still too early: The number of events observed is not yet large enough to statistically rule out a random effect. However, the fact that two independent experiments, ATLAS and CMS, both point in the same direction, creates excitement and raises hopes that this could indeed be the mysterious Higgs particle.
The Higgs boson was predicted in 1964. Within the theory, it would give mass to the other elementary particles of the Standard Model. According to the physicists, the entire universe is filled with the so-called Higgs field. Depending on how strong the individual elementary particles couple to the Higgs boson, they would have more or less mass. If the missing particle is actually discovered, this would not only confirm a model but would also mark the beginning of a new field of research. The LHC provides ideal conditions to study the Higgs field and the origin of mass in detail, especially with the even higher proton beam energy scheduled for 2014 onwards.
The researchers of the working group for Experimental Particle and Astroparticle Physics (ETAP) at Johannes Gutenberg University Mainz are involved in particular in the ATLAS experiment, one of two major experiments at the LHC. The ATLAS detector is 46 meters long, 25 meters high, and 25 meters wide. It is able to detect and precisely measure new particles produced during proton collisions. A total of approximately 3,000 researchers from all over the world are taking part in the ATLAS experiment.
Read more at Science Daily
After analyzing 54 published studies of Old World skeletons, researchers concluded that syphilis originated in the New World as a non-sexually transmitted disease and then mutated into a venereal version after it arrived in Europe in the 1490s.
This theory -- that syphilis crossed the Atlantic from west to east instead of the other way around -- has been around for decades, but some scientists still debate the origins of this disease which continues to have a major global health impact. The ongoing conversation reinforces the importance of understanding how diseases spread -- both in the past and today.
"This is probably one of the first examples of European diseases contracted from Native Americans," said George Armelagos, a bioarchaeologist at Emory University in Atlanta. "It's a really good example of the globalization of disease. It's showing that this is not a modern problem. It's been happening for 500 years."
Modern syphilis is a sexually transmitted disease that’s spread by a bacterium called Treponema pallidum. Over the centuries, syphilis has been used in biological warfare and it has been implicated in the health problems of many famous figures, including Louis XIV, Beethoven, and Hitler. As of 2006, there were 36,000 cases of syphilis in the United States, according to the Centers for Disease and Prevention, with millions more cases around the globe.
But scientists have yet to fully agree about how it all started, Amrelagos said, with arguments beginning soon after Columbus’ return to Europe was followed in 1495 by a syphilis outbreak in Italy -- the first documented epidemic of the disease in the Old World.
Since then, some researchers have argued that syphilis bacteria had long been present in Europe at low levels, and that some unknown force triggered an outbreak in the late fifteenth century.
Others, including Armelagos, argue that the only skeletons showing evidence of infection with syphilis before 1492 were in the New World.
At the heart of the debate are questions about the accuracy of both dating and diagnosing ancient skeletons. Treponema infections leave telltale pits and scars on skulls and thickening of bones. But other diseases can cause those kinds of signs, too. And syphilis is just one of at least three diseases caused by various kinds of Treponema bacteria.
For the new study, Armelagos and colleagues re-analyzed 54 published reports of treponemal disease in the Old World before Columbus set sail. Where details were vague, the researchers also contacted study authors for photographs and other information.
Not a single report of pre-Columbian syphilis in Europe, they concluded in the Yearbook of Physical Anthropology, included enough information to confirm a diagnosis of the disease. There is evidence, on the other hand, of the syphilis in the New World dating back at least 7,000 years.
Those findings echo what University of Kansas paleoosteopathologist Bruce Rothschild concluded two decades ago. He said that his team has found that a diagnosis of treponemal disease in a single skeleton has, at best, a 70 percent chance of being correct.
And there remains no standard, reliable technique for making posthumous diagnoses of syphilis. At one New World site, for example, different studies have estimated the prevalence of anywhere from zero to 100 percent of skeletons affected by the disease.
Settling questions about how diseases have spread in the past could have future public health implications.
Read more at Discovery News
As an exhibition at the Smithsonian Institution's National Museum of Natural History in Washington, D.C. shows, almost no animals escaped the carnage.
Although pets died of natural causes before their mummification, and sacred beasts were pampered by adoring priests, most animals in ancient Egypt had miserable, short lives.
Many were simply bred to become votive mummies -- offered to the gods in the same way that people light up candles in churches today.
"Various gods had different animal totems or avatars. Priests who maintained temples for these different gods offered a service whereby people could have an associated animal mummified and placed in a catacomb in their name," exhibition curator Melinda Zeder, director of the archeobiology program at the Smithsonian Institution's National Museum of Natural History, told Discovery News.
Began as early as 3,000 BC, the practice reached its zenith from about 650 BC to 200 AD.
"Literally millions of animals like dogs and cats were raised by temple priests and mummified. This practice extended to wild animals like the sacred and glossy ibis and the baboon -- and may have contributed to the extinction of these animals in Egypt," Zeder said.
The sacred ibis and baboons were mummified in the millions because they were sacred to Thoth, the god of wisdom and writing. Raptors were associated with Horus, the falcon god, while cats were sacrificed to the protective goddess Bastet.
Kittens were the preferred choice as they could fit into mummy containers easily.
Researchers estimate that millions of cat mummies were produced when animal mummification was at its peak in Egypt.
In the late 1800s these cat mummies were even sold for agricultural purposes. Indeed, a company bought about 180,000 cat mummies, weighing some 38,000 pounds. Once pulverized, they were used to fertilize the fields of England.
Ibis and baboons were also very popular for mummification, so popular that they went extinct. This gave rise to a market of fake mummies, revealed only recently by modern CT scans.
While looking like ibis and baboons on the outside, these mummies were made instead from other animals.
Among some of the lucky animals were pigs and male hippos. As far as researchers know, there are no mummies of these animals.
"Pigs and male hippos were associated more closely with the god Seth. In the later periods of Egyptian history, when animal mummification was increasingly popular, Seth was less well regarded than other deities," Salima Ikram, a professor of Egyptology at the American University in Cairo who helped curate the Smithsonian's exhibition, told Discovery News.
Read more at Discovery News
So, using data from the Kepler space telescope, astronomers are becoming more focused on "listening" for radio signals coming from stars known (or at least thought) to have planets orbiting them. And it seems the first "candidate" signals have been detected!
But before you start popping the "we've discovered ET!" champagne corks, this first signal is most likely terrestrial in origin.
"We've started searching our Kepler SETI observations and our analyses have generated some of our first candidate signals," scientists of the University of California, Berkeley announced on Friday.
Sadly, the first candidate signals aren't lucky detections of alien radio transmissions, they're "undoubtedly examples of terrestrial radio frequency interference (RFI)."
Although it's interference from a source here on Earth, the detection of any artificial signal provides the UC Berkeley team with a great opportunity to understand the kind of artificial (alien) signals they hope to eventually discover.
From the UC Berkeley website:
"These signals look similar to what we think might be produced from an extraterrestrial technology. They are narrow in frequency, much narrower than would be produced by any known astrophysical phenomena, and they drift in frequency with time, as we would expect because of the Doppler effect imposed by the relative motion of the transmitter and the receiving radio telescope."
NASA's Kepler space telescope is currently looking for exoplanets orbiting other stars. It does so by constantly looking at the same patch of sky, waiting for these alien worlds to pass in front of their parent stars. When an exoplanet does that -- an event known as a "transit" -- the starlight dims slightly, and Kepler registers a "candidate" exoplanet.
For the world to be confirmed, it needs to complete four transits. As one of Kepler's prime mission objectives is to discover Earth-sized exoplanets orbiting within the habitable zone of sun-like stars, we have to wait 3.5 years until Kepler can confirm their existence.
As explained in the Discovery News article "Big Question for 2012: Will We Find Earth 2.0?," we may start to glimpse hints of the first true "Earth-like" worlds orbiting other stars by the end of 2012.
Read more at Discovery News
Jan 5, 2012
Over 350 newly discovered tracks, made by various dinosaurs, crocodiles and a few pterosaurs, were identified at the site, which is now the John Martin Reservoir in Bent County, Colorado. When added to previously found tracks there, the total number of fossilized prints is well over 1,000. The dinosaur freeway is described in the February issue of Cretaceous Research.
"The Dinosaur Freeway runs from Northeast Colorado, near Boulder, to east central New Mexico, near Tucumcari," co-author Martin Lockley told Discovery News. "It is a trampled zone in Cretaceous rocks representing an ancient coastal plain like the present day Gulf of Mexico."
Lockley is a professor of geology at the University of Colorado Denver and serves as director of the Dinosaur Tracks Museum. He and colleague Reiji Kukihara found and analyzed the animal tracks.
An ornithopod dinosaur that was probably an Iguanodon-like species made the most common prints. Iguanodons were bulky, large, plant-eating dinosaurs, with some having large thumb spikes that were possibly used for defense against predators.
Based on the prints, other travelers along the Dinosaur Freeway included armored Ankylosaurs and ostrich-like dinos that were probably ornithomimids.
"Sometimes the ornithopod dinosaurs appear to have walked in herds," Lockley said. "Their trackways are parallel and equally spaced, and sometimes they all belong to individuals of similar size."
Swim tracks for large crocodiles, some over 13 feet long, were also found near the Dinosaur Freeway.
Lockley explained that, back in the dino day, the freeway was the coastal plain to the Cretaceous Western Interior Seaway, which ran north to south and split North America during this period of time.
"It was riddled with waterways and wetlands ideal for crocs," he said. "The crocs were not wimpy."
Dinosaurs therefore probably sped on by, likely migrating to find new forage. The animals may have traveled in groups by age. Juvenile and subadult dinosaurs were more dominant in the south, accounting for almost half of all identified tracks in that region. The proportion of juveniles sharply reduces in the middle area, and almost disappears in the north.
Lockley shared that other similar dinosaur thoroughfares have been discovered in Utah and Switzerland, both dating to the Jurassic Period.
Read more at Discovery News
The classical period Mayans in Central America and the Khmer in Southeast Asia both hacked a space for their people out of tropical forests and constructed impressive stone cities with sophisticated water storage systems. But their Achilles heel was a dependence on seasonal rains for their crops and drinking water. When regional climate changes caused erratic rainfall, their cities and fields may have dried out and left them vulnerable to collapse.
Between the 9th and 15th centuries, the Khmer Empire dominated much of what is now Laos, Cambodia, Thailand, Vietnam and Burma (Myanmar). The empire's famous capital, Angkor, may have been one of the largest pre-industrial city complexes in the world. The empire was supported by an extensive water management system, including lake-sized reservoirs called barays.
But reservoirs only work if there is rainwater to fill them. Research recently published in the Proceedings of the National Academy of Sciences suggests that a series of erratic monsoons may have destabilized the once-mighty Khmer.
Researchers led by Mary Beth Day, an earth scientist with the University of Cambridge, found evidence of a series of failed monsoons in 14th and 15th century that coincided with the Khmer's collapse. Sediments in the largest Khmer resevoir, the West Baray, showed that extremely heavy downpours were followed by drought. The heavy rains may have washed away crops, and those that survived shriveled in the drought. During the dry spells, drinking water may have run low as well.
Although many other factors came into play, such as the threat of Mongol invasion and social upheaval brought on by the spread of Theravada Buddhism, the researchers note that an inability to feed their people could have weakened the Khmer to the point of collapse.
The Mayans of the classical period (c. 250 – 900 AD) could have warned the Khmer. While the Khmer were rising, the classical Mayans were falling, possible because the rains weren't.
The Mayans too seem to have been dependent on seasonal rains. They often built their cities near natural reservoirs called cenotes or near rivers, then augmented nature with their own water management systems, such as the dam at Kinal and reservoirs at Uxul. Mayans even had pressurized water.
Read more at Discovery News
Jan 4, 2012
Wegener's genius idea did not only find friends, because it had the main disadvantage that it lacked the engine to break apart the supercontinent and move huge continental masses over Earth's surface. Indeed, only by the seismology of the 1950s and through scientific drilling in the oceans in the 1960s, the foundation for plate tectonics was laid -- at the same time, however, Wegener's groundbreaking theory was turned upside down.
Earthquakes are not only terrible natural disasters, they also offer a view inside Earth. It was the geophysicists Wadati and Benioff, who in 1954 independently discovered the systematic arrangement of earthquakes in the places which we now know as plate boundaries. "More than 90% of the global seismic energy is released at the plate boundaries," says Professor Michael Weber, head seismologist at the German Research Centre for Geosciences GFZ. "We use these earthquakes for tomographic screening of the Earth." With modern methods of scientific seismology it is even possible to reconstruct how quickly the continents moved. The speed record is held by India, which started to make its way from East Gondwana to Eurasia about 140 million years ago -- at a speed of 20 centimeters per year.
Drilling into the ocean floor
The real breakthrough, however, came only when those findings were combined with the research results from the great ocean drilling programs of the sixties. Previously, using magnetic measurements of the ocean floor and topography of the seabed the mid-ocean ridges had been discovered, as well as a magnetic polarization of the rocks in parallel strips either side of mid-ocean ridges. Now, the obtained cores showed: No piece of the drilled ocean floor was older than 200 million years, and therefore decidedly younger than Wegener had assumed. Continental rocks, in contrast, can achieve an age of more than four billion years. Secondly, it could be shown that the ocean floor is very young in the immediate vicinity of the mid-ocean ridges. With increasing distance from these undersea mountains, the rocks exhibit an increase in age. Thirdly, the ocean floors below the top layer of sediment are entirely of magmatic origin. "These results could in fact only allow one interpretation. From the interior of the Earth, hot, liquid rock rises to these ridges and pushes the ocean floor off to the side", explains Dr. Ulrich Harms, who at the GFZ directs the "Centre for Scientific Drilling." "Not the continents drift, but entire tectonic plates, which consist of continents , ocean floors, and parts of the upper mantle."
Ascending rocks and the engine of plate tectonics
All these findings in the second half of the sixties put Wegener's ingenious discoveries into a correct context, and also flipped his theory from the head to its feet: not only were his assumptions as to the age of oceans and continents completely reversed, the idea that the continents plow the ocean turns around so that continents and oceans move together as a common upper part of the lithospheric plates. The continents float on top as the lightest rocks, so to speak.
These tectonic plates move, collide, grind past each other or drift apart. All these processes are associated with earthquakes, which can thus be explained as part of the overall process. But what forces the heavy rock inside Earth to rise? The enormous heat inside Earth's core and mantle comes in one part from the formation of Earth, in another from the radioactive decay of elements in the mantle. The heated rock rises and induces the movement expressed on the surface as a displacement of the plates.
The quiet revolution in the theory of tectonics
The classical concept of tectonics as a quasi mechanical process of the movement and collision of rigid plates is now itself in disarray. "Recent findings show plate tectonics as a self-regulating system of interactions, in which all the subsystems of the planet earth are involved", explains Professor Onno Oncken. The Director of the Department "Geodynamics" at GFZ notes: "It is not a mechanical system, but rather complex feedback processes." The climate as example: high-altitude mountains have a decisive influence on the climate, of course. But that the climate in turn controls the tectonics, is a new discovery: the Andes, for example, are caused by the collision of the Nazca plate with South America. The humid climate of the South Andes leads to the erosion of material that ends up as sediment in the Pacific. The Nazca plate approaching from the west deposits this rock on the South American crust. The arid climate of the Northern and Central Andes, however, gives rise to no sediment, therefore the Nazca plate rasps off the continental crust here. The thus created great increase in friction in turn transmits a force that causes the Andean plateau to gain height and width. This in turn enhances the rain shadow on the west side of the Andes and additionally reduces erosion.
The classical notion of folded mountains as a result of a collision also had to be revised: "The Andes, for example, in their present form, exist for about 45 million years, the subduction of the Nazca plate beneath South America has been going on since the Paleozoic, so hundreds of millions of years longer," says Onno Oncken. Similarly, the interplay between the hot, rising rock masses and Earth's crust is much more complex than originally thought. When a hot rock bubble rises, the poorly heat-conductive lithosphere acts as a boundary layer to the surface like a blanket, which in turn increases the temperature further below. This heat buildup can eventually soften whole continents like a welding torch until they dissolve, as it happened around 140 to 130 million years ago, when Gondwana fell apart first in the East, then in the West.
Read more at Science Daily
That's according to findings from University of Cincinnati research at Pompeii being presented Jan. 7, 2012, at the annual meeting of the Archaeological Institute of America by UC doctoral student Allison Emmerson. She has worked on site as part of UC's Pompeii Archaeological Research Project.
New Research Counters Long-held Assumptions
Emmerson's research counters long-held assumptions about how and why tombs around Pompeii have been found piled high with ancient trash deposits in and around the structures, including butchered and charred animal bones, dog and equine bones, broken pottery and broken architectural material. These garbage materials in cemeteries were found within and alongside tomb structures, even those of one story which were preserved nearly as they existed in AD 79 because of the thick, hardened coating of ash and lapilli (small stones) that covered and preserved them due to the AD 79 eruption of Vesuvius.
The 19th century excavators at Pompeii assumed that the excavated tombs filled with ancient refuse and garbage (as well as covered in graffiti) must have fallen into decline and disrepair almost two decades prior to the AD 79 catastrophic eruption of Vesuvius. They (and later excavators) theorized that Pompeii's tombs were covered in garbage due, in part, to a powerful AD 62 earthquake at Pompeii and that the tombs were abandoned and neglected after the earthquake as the city must have been in decline and inhabitants focused on more pragmatic concerns..
It was a theory, according to Emmerson, that was likely adopted because the 19th century researchers working at Pompeii (as well as later excavators) would have found it unthinkable that cemeteries were places appropriate for tossing out the trash.
However, recent scholarship of the last 15 years or so has proven that Pompeii had rebounded after the earthquake of AD 62 and was in a period of rejuvenation by AD 79 as an important city in one of the wealthiest regions of the Roman Empire.
"Which," according to UC's Emmerson, "Left the question of why so much trash was found in the cemeteries. These were not abandoned locales as of AD 79 . People had not abandoned the maintenance of their burial spaces and structures any more than they had abandoned public spaces."
The Ancients Held a Casual View of Trash Collection
As Emmerson began excavations at Pompeii in 2009, as part of a long-term team of UC faculty and students working there, she noted the placement of Pompeii's tombs -- located not in secluded park-like areas set off by a fence (as are our cemeteries today) but prominently placed along well-used, high-traffic roads and thoroughfares of the time.
She also noted what we would consider an extremely "casual" treatment of trash and waste.
"For instance," she explained, "I excavated a room in a house where the cistern (for storing drinking water and water for washing) was placed between two waste pits. Both waste pits were found completely packed with trash in the form of broken household pottery, animal bones and other food waste, like grape seeds and olive pits."
In addition, researchers have commonly found that garbage was casually deposited on the floor of homes, in the streets and alleys outside of homes (sometimes at significant layered depths) and at the urban edge, along city walls (in large quantities over time).
In fact, there is no evidence that Pompeii had any centrally managed system for garbage disposal, and so, it's likely people lived in very close proximity to their refuse as an accepted part of life.
And Pompeii's cemeteries and tombs were simply another place for trash -- as were almost any part of a home's interior or exterior as well as alleys, streets and major roadways.
Tombs and cemeteries were certainly considered appropriate for the placement of "advertisements" of the time, everything from political "vote for me" material, promotions for sporting events or boasts of sexual conquest.
"In general, when a Roman was confronted with death, he or she was more concerned with memory than with the afterlife. Individuals wanted to be remembered, and the way to do that was a big tomb in a high-traffic area. In other words, these tombs and cemeteries were never meant to be places for quiet contemplation. Tombs were display -- very much a part of every day life, definitely not set apart, clean or quiet. They were part of the 'down and dirty' in life."
Read more at Science Daily
The distant relationship between the two modern sloth genera – species of two-toed sloth are grouped under Choloepus, and three-toed species under Bradypus – isn’t immediately obvious. Both suspend their bodies beneath tree limbs by their hooked claws, and they slowly clamber along upside-down. If we had no knowledge of the fossil record, we would expect that these animals are the descendants of some relatively recent sloth that moved in the same way.
What actually happened isn’t that simple. In addition to anatomical comparisons between modern and fossil sloths, genetic studies involving DNA extracted from the skin and dung of extinct species have found that two-toed sloths are most closely related to genera such as Megalonyx, and three-toed sloths belong to a different sloth subgroup which includes behemoths akin to Megatherium. Exactly when two- and three-toed sloths last shared a common ancestor isn’t clear, but, on the basis of their relationships, both lineages probably go back to a species which trundled along on the ground. This is consistent with what is known from the fossil record. So far, no one has found an extinct sloth which moved upside-down through the canopy like modern species do.
Both two- and three-toed sloths converged on a similar form despite their distant relationship. As anatomist John Nyakatura outlined in a recent Journal of Mammalian Evolution review, the deep history and evolutionary context of sloths may explain why.
Sloths are xenarthrans – their closest relatives include anteaters and armadillos. And, among other things, large, curved claws and powerful forelimbs for digging are common xenarthran traits. It’s likely that the last common ancestor of two- and three-toed sloths shared these features, too. If this is correct, then these traits may have been co-opted when smaller sloths moved into the trees and therefore allowed the peculiar mammals to create a new niche for themselves. Strong arms with hooked claws can be just as useful for climbing through the trees as they are for digging on the ground.
Nyakatura suggests that the silky anteater might serve as a rough intermediate between early, earthbound sloths and the modern, topsy-turvy species. Like other xenarthrans, this anteater has curved claws and powerful forelimbs, but, while climbing through the trees, is capable of moving both above and below branches. The ancestors of modern sloths probably went through a similar stage. “Similar to the silky anteater,” Nyakatura writes, “small to medium sized arboreal [sloths] with strong limb flexor groups and strong, curved claws already in place, may have been able to locomote above the branch, but also in a suspended posture.”
But why do sloths hang upside-down? Many other tree-dwelling mammals – from squirrels to monkeys – run along the tops of branches. What caused sloths to eventually adapt to a different perspective? The answer probably has something to do with saving energy. When a creature moves along the top of a tree branch, Nyakatura points out, the animal has to balance. Sloths sidestep this extra energy expenditure by simply hanging below branches. More than that, xenarthrans typically have low metabolic rates compared to other mammals, so the similar evolutionary patterns in two- and three-toed sloths may partially stem from a shared physiology.
Read more at Wired
All four alien worlds are known as "hot Jupiters" -- large gas giant planets orbiting very close to their stars. Their orbits are aligned just right with the Earth so that when they pass in front of their parent stars, they slightly dim the starlight from view.
As exoplanets pass in front of their stars, a small dip in star brightness may be detected. This detection method is known as the "transit method." This is in addition to the "radial velocity method," when the gravitational pull of an exoplanet causes its parent star to wobble slightly.
However, this most recent discovery doesn't come from NASA's Kepler space telescope team or any other space telescope, it comes from a ground-based telescope system maintained by the Harvard-Smithsonian Center for Astrophysics.
The Hungarian-made Automated Telescope Network (HATNet) Project consists of six small (11-cm diameter), wide-field automated telescopes based at the Fred Lawrence Whipple Observatory, in Arizona and The Submillimeter Array atop Mauna Kea, Hawaii.
Follow-up observations were made by Keck Observatory (also on Mauna Kea), the KeplerCam CCD camera (at FLWO) and Faulkes Telescope North at Haleakala Observatory in Hawaii.
The HATNet telescopes were established in 2003, and the system announced their first exoplanet discovery in 2006 (called HAT-P-1b). Now they have another four exoplanets, orbiting four different stars, to add to their growing list.
HAT-P-34b, HAT-P-35b, HAT-P-36b and HAT-P-37b have very tight orbits around their stars, completing a "year" in only 5.5-, 3.6-, 1.3- and 2.8-days respectively. Remember, the Earth orbits the sun every 365 days.
Apart from having breakneck orbital speeds, one of the exoplanets (HAT-P-34b) is notable for having a very elongated -- or "eccentric" -- orbit. Only four other transiting exoplanets are known to have more eccentric orbits.
Read more at Discovery News
Jan 3, 2012
The scientists are the first to confirm the existence of brucellosis, an infectious disease still prevalent today, in ancient skeletal remains.
The findings, which appear in the American Journal of Physical Anthropology, suggest brucellosis has been endemic to Albania since at least the Middle Ages.
Although rare in the United States, brucellosis remains a major problem in the Mediterranean region and other parts of the world. Characterized by chronic respiratory illness and fever, brucellosis is acquired by eating infected meat or unpasteurized dairy products or by coming into contact with animals carrying the brucella bacteria.
Todd Fenton, associate professor of anthropology, said advanced DNA testing at MSU allowed the researchers to confirm the existence of the disease in skeletons that were about 1,000 years old.
"For years, we had to hypothesize the cause of pathological conditions like this," Fenton said. "The era of DNA testing and the contributions that DNA can make to my work are really exciting."
Here's how the discovery came about.
Fenton and a group of MSU graduate students were serving as the bioarcheologists, or bone specialists, for a multinational team of archaeologists excavating sites in the ancient Albanian city of Butrint. Once a large Roman colony, Butrint in its final centuries served as an outpost of the Byzantine Empire until it was abandoned in the Middle Ages due to flooding.
Fenton and his team developed biological profiles of the human remains, which included determining sex, age and skeletal pathologies, or health histories. Vertebrae from two of the Byzantine-era skeletons -- both adolescent males from the 10th century to the 13th century -- had significant lesions, leading the researchers to theorize the boys had suffered from tuberculosis.
Samples of the ancient bone were sent to the forensic DNA lab in East Lansing, which is headed by David Foran, director of MSU's Forensic Science Program. Foran and his team of graduate students took tiny portions of the bone, extracted DNA and tested it for any residual DNA that might still exist from the expected pathogen.
But the results came back negative for tuberculosis.
Fenton's team re-examined the bones that tested negative for tuberculosis and concluded the disease might instead be brucellosis. The infection from brucellosis and tuberculosis causes similar damage -- basically eating away the bone -- although no one had ever confirmed brucellosis in human bone recovered from an archaeological site.
Foran's team then developed a different set of tests for detecting the brucella bacteria and undertook a new round of testing on the diseased vertebrae.
This time the results came back positive for brucellosis.
Foran said the collaboration on the project highlights the benefits of modern science and interdisciplinary research, even when the respective research teams are some 5,000 miles apart.
"In this case it was a combination of inquisitiveness, persistence and of course collaboration," Foran said. "It is amazing to find something brand new in something that is a thousand years old."
Read more at Science Daily
The mating of the local Australian black-tip shark with its global counterpart, the common black-tip, was an unprecedented discovery with implications for the entire shark world, said lead researcher Jess Morgan.
"It's very surprising because no one's ever seen shark hybrids before, this is not a common occurrence by any stretch of the imagination," Morgan, from the University of Queensland, said.
"This is evolution in action."
Colin Simpfendorfer, a partner in Morgan's research from James Cook University, said initial studies suggested the hybrid species was relatively robust, with a number of generations discovered across 57 specimens.
The find was made during cataloging work off Australia's east coast when Morgan said genetic testing showed certain sharks to be one species when physically they looked to be another.
The Australian black-tip is slightly smaller than its common cousin and can only live in tropical waters, but its hybrid offspring have been found 2,000 kilometers (1,243 miles) down the coast, in cooler seas.
It means the Australian black-tip could be adapting to ensure its survival as sea temperatures change because of global warming.
"If it hybridizes with the common species it can effectively shift its range further south into cooler waters, so the effect of this hybridizing is a range expansion," Morgan said.
"It's enabled a species restricted to the tropics to move into temperate waters."
Climate change and human fishing are some of the potential triggers being investigated by the team, with further genetic mapping also planned to examine whether it was an ancient process just discovered or a more recent phenomenon.
If the hybrid was found to be stronger than its parent species -- a literal survival of the fittest -- Simpfendorfer said it may eventually outlast its so-called pure-bred predecessors.
"We don't know whether that's the case here, but certainly we know that they are viable, they reproduce and that there are multiple generations of hybrids now that we can see from the genetic road map that we've generated from these animals," he said.
"Certainly it appears that they are fairly fit individuals."
The hybrids were extraordinarily abundant, accounting for up to 20 percent of black-tip populations in some areas, but Morgan said that didn't appear to be at the expense of their single-breed parents, adding to the mystery.
Simpfendorfer said the study, published late last month in Conservation Genetics, could challenge traditional ideas of how sharks had and were continuing to evolve.
Read more at Discovery News
Confined to a wheelchair and dependent on a voice synthesizer to talk, Hawking relies more than most on technology to live and work. The British cosmologist and author is nearly paralyzed by the incurable motor neuron disease amyotrophic lateral sclerosis, or ALS. He lost his voice in 1985 after an emergency tracheotomy.
Hawking plans to hire an assistant to help develop and maintain the electronic speech system that allows him to communicate his vision of the universe, according to an Associated Press report.
An informal job ad posted on Hawking's website said the assistant should be computer literate, ready to travel, and able to repair electronic devices "with no instruction manual or technical support," AP reports.
The ad has since been removed from Hawking's website and replaced with a note stating that the “post of Technical Assistant to Stephen Hawking will be advertised officially in due course” on the University of Cambridge’s Department of Applied Mathematics and Theoretical Physics website.
Read more at Discovery News
Scientists say the underwater plumes -- located between the southern tip of South America and the Antarctic Peninsula -- are chock-full of new species, including a pale, ghostly-looking octopus, a predatory seven-legged sea star and a hairy-chested "yeti" crab.
Experts say the strangest thing is what they didn't find -- tube worms, shrimp and mussels that have been found at the world's other deep-sea hydrothermal vent communities.
"It wasn't just one creature, virtually everything we saw was new to science," said Alex Rogers, professor zoology at the University of Oxford and lead author of the new report.
"It was a remarkable experience. You're not quite sure if these things are mineral or biological structures. That's a very unusual feeling to see all this stuff for the first time and saying I don't understand what's going on here."
Rogers and his colleagues at the University of Southampton described their findings in today's PLOS Biology.
The discoveries came during a January and February 2010 expedition to the region and were made using a remote-operated vehicle (ROV) called Isis.
Rogers said it took nearly two years to get the findings published because there were so many undescribed species that his team had to send samples out to experts around the world for identification.
He recalled watching a small video screen on board the British oceanographic vessel James Cook as the ROV camera descended 2,600 meters (8,530 feet) down to the seafloor.
"The robot camera captured images of smoking plumes of hydrogen sulfide and minerals billowing up from fissures in the undersea ridge up to 382 degrees Celsius (720 degrees Fahrenheit) and surrounded by vast living mats of barnacles, anemones, crabs and other critters."
"It's probably the most exciting scientific cruise I've ever taken part in," Rogers said from his office in England.
"The wonderful thing was that the discoveries just kept coming right through the trip. Seeing the images for the first time was absolutely breathtaking, just stunning."
But beyond the giddy excitement of finding new animals, marine biologists say that the mix of deep-sea fauna at these vents will stir debate about how these creatures got there.
"The Rogers paper fills in a piece of the bio-geographic puzzle for global vent faunas and raises new questions about evolutionary alliances and pathways to hydrothermal vents," said Cindy Van Dover, director of the Duke University Marine Laboratory, and a leading expert in undersea hot springs biology, in an email to Discovery News.
"Their discovery of dense populations of crabs related to the yeti crab is especially intriguing. This family of crabs was discovered in 2005 at hot springs in the southeastern Pacific -- there must be an evolutionary link between the two regions."
That means that the creatures living at underwater hot springs must be able to colonize other vents, even though the plumes often are short-lived, lasting only a few decades before the seafloor shifts and the hot springs disappear.
Another big question is whether the extremely cold water that circles Antarctica helps or hinders dispersal of the larvae of the strange life that thrive at the vents.
"Depending on the group of deep-sea organisms, the Southern Ocean can be an ecological dead end or a jumping-off point for colonizing other parts of the world," said Rich Aronson, head of the department of biological sciences at the Florida Institute of Technology who studies Antarctic undersea life.
Read more at Discovery News
Jan 2, 2012
Their conclusions are due to be published in the first quarter of 2012 in the Journal of Cultural Heritage and could prove to be of value to other historical sites across the world.
In Belgrade, fortifications were built from the Middle Ages on the Kalemegdan plateau, which stands above the confluence of the Danube and Sava rivers. Today, the ramparts of the fortress of the Serbian capital have become a vast public park with flowers and shady areas, near the town centre, attracting inhabitants and tourists alike. However, during the last twenty years or so, black crusts have been spreading on its limestone walls. Until now, these crusts were solely attributed to the high levels of sulfur dioxide released by the coal heating used by the inhabitants of Belgrade.
In collaboration with Philippe Colomban, CNRS researcher at LADIR, the University of Belgrade and the Serbian Highway Institute analyzed the black crusts on the "King's Gate" of the fortress. Their objective was to determine the actual deterioration process in order to propose the most appropriate conservation solutions to the authorities. Different samples of the limestone and lime mortars were studied by porometry*, X-ray diffractometry, infrared and Raman spectroscopy, electron microscopy and elementary analysis.
Above a certain concentration of sulfur dioxide in damp air, acid rain or acid fog can form. This leads to the emergence of "black" calcium sulfates and carbonates, giving the outer walls a somewhat unsightly appearance. Surprisingly enough, the researchers detected large amounts of syngenite, a double sulfate of potassium and calcium. This corrosion product normally forms on potassium-containing medieval stained-glass windows, as well as granite constructions or those using a mortar containing potassium. Yet it had never been observed on very pure limestone before.
So where does it come from? After performing a series of analyses, the researchers revealed an abnormal concentration of potassium in the soil, near the rampart walls. Incidently, the latter contain flowerbeds where potassium-rich fertilizers are used. A simulation of the action of acidified potassium-charged water on pieces of limestone confirmed that it triggered the formation of syngenite, as observed on the "King's Gate."
Read more at Science Daily
Due to diffraction limit, optical microscopes will never be able to discern details smaller than 200 nanometres -- it was believed only a dozen or so years ago. In recent years, scientists have managed to overcome this limit and build super-resolution devices, including, for example, STED confocal microscopes. A prototype device of this type has recently been built at the Faculty of Physics, University of Warsaw (FUW), as part of Joanna Oracz's MA thesis. As of next year, the new microscope will be used not only for research in the field of optics but also to analyze biological samples.
There are many imaging techniques with a resolution of the order of nanometres (billionths of a metre) known to science, for example, electron or atomic force microscopy. These techniques require special preparation of samples and make it possible to observe only the surface itself. When it comes to samples of biological origin, not infrequently living ones, optical microscopy is still second to none. One of its advantages is the possibility of observing the spatial structure of the sample. A major disadvantage, however, is a low resolution.
An optical microscope makes it possible to discern details no smaller than half the wavelength of the light illuminating the sample. This limit is due to diffraction, which makes it impossible to focus the beam of light onto a point. As a result, if we use a red light source with a wavelength of 635 nanometres, we can, at best, see details around 300 nanometres in size.
In 1994 Stefan W. Hell from the Max-Planck-Institut für biophysikalische Chemie in Göttingen proposed a theoretical way to overcome the diffraction limit in optical microscopy by means of stimulated emission depletion (STED). Five years later he built the first super-resolution STED fluorescence microscope.
In standard fluorescence confocal microscopy, a laser beam scans a biological sample and locally excites dye molecules, introduced into the sample earlier. Upon excitation, the molecules begin to emit light. The light is passed through a filter and recorded by a detector located behind a confocal aperture. Due to the size of the aperture, light from out-of-focus planes is eliminated, increasing the contrast of the image. The dye itself is selected in such a way that it accumulates in those parts of a living cell that are of interest to researches.
An additional laser beam -- depletion beam -- is used in STED microscopy. Given its wavelength, the beam induces stimulated emission in dye molecules it illuminates. Molecules that have lost energy as a result of stimulated emission are no longer able to fluoresce. Therefore, their light (similarly to the light from stimulated emission) will not pass through the filter in front of the detector, and they will not be visible on the recorded image.
The essence of the STED method lies in the fact that the depletion beam is donut-shaped. If a beam of this shape is properly synchronized in time and space with the illuminating beam, fluorescence will occur first and foremost in the area of the sample located in the centre of the depletion beam.
"Thanks to the second beam, the area of the sample emitting light as a result of fluorescence is distinctly smaller than the diameter of laser beams. The effect is as if the illuminating beam were better focused, meaning that we can scan the sample with a higher resolution," explains Joanna Oracz, adding that when she began working on her device a year ago, there was only one STED microscope in Poland, purchased for a million and a half euros.
The confocal microscope with a STED setup was built at the Faculty of Physics, University of Warsaw, using commercially available elements. The greatest problem was to ensure that both laser beams overlapped. "In order to observe the STED effect, both beams need to be ideally aligned -- the minimum of the depletion beam needs to closely overlap with centre of the excitation beam," says Oracz.
The prototype microscope at FUW has a resolution of about 100 nm, over two times higher than that of a standard confocal microscope. Works are still underway to increase the resolution. "The advantage of our microscope is the possibility of controlling all parameters and studying the physics of the optical phenomena occurring," stresses Oracz, currently a PhD student at the Ultrafast Phenomena Lab of the Institute of Experimental Physics FUW. The aim is to reach a resolution of about 60 nm. It would make it possible to observe details as minute as dendritic spines of neurons.
Read more at Science Daily
Jan 1, 2012
So here are 11 technology giants who left us this year, and the amazing legacies they left behind.
Dennis Ritchie is one of those little-hailed computer science pioneers whose work has ended up influencing everyone in technology. If your computer isn't running some component of Unix, the operating system he helped build, it's probably using software written in C, the language he created.
"It’s really hard to overstate how much of the modern information economy is built on the work Dennis did," said Rob Pike, a Google distinguished engineer who once worked across the hall from Ritchie at Bell Labs.
Gentle and far-from-flashy, Ritchie was in some ways the opposite of Jobs. He watched Unix and C take off because of their technical superiority, and he never cashed in on the success of his incredibly popular software. He stayed at Bell Labs for 40 years because he liked working with scientists and being able to stumble into canisters of liquid helium while at work.
The first computer to run Unix was a PDP-7, and the company that built it was Digital Equipment Corp. (DEC), which was co-founded by Ken Olsen.
Olsen wasn't exactly a fan of Unix, but he was a computer pioneer back in the '50s -- starting up DEC with Harlan Anderson in an old wool mill in Maynard, MA. Thirty years later, Fortune magazine called him "arguably the most successful entrepreneur in the history of American business."
Back in the '80s, DEC was one of the hottest technology companies around. As DEC's longstanding president, Olsen built DEC into the country's number-two computer company, before it was finally swallowed by Compaq, which was itself consumed by Hewlett-Packard. DEC was a victim of the PC revolution that ultimately killed off the company's lucrative PDP and Vax systems.
Read more at Wired
What did we experience as the year came to an end? Global earthquakes? A planetary collision? Weird gravitational effects caused by an alignment with the galactic plain? A comet impact? Global enlightenment?
As much as I'd love the latter to be true, the New Year celebrations most likely just involved a ton of alcohol and fireworks. It's the start of a brand new year for our calendar. Nothing more, nothing less.
ANALYSIS: 2012 Mayan Calendar 'Doomsday' Date Might Be Wrong
But it is the beginning of a much hyped year. Rather than being the year of the U.S. presidential election or the London Olympics, 2012 has been hijacked by a small group of strange people who seem hellbent on insisting that, by the end of the year, some kind of apocalyptic scenario will play out.
According to them, on or around Dec. 21, 2012, the world will "come to an end." Well, to quote Penn & Teller, that's "Bullsh*t!"
In case you've been living under a rock since 2009, you may have noticed an upsurge in the "2012 doomsday" nonsense -- 2009 was the year of a bad John Cusack disaster movie involving killer solar neutrinos and a crazed Woody Harrelson. It was also the year that doomsday went mainstream. In the run-up to the release of "2012," a Sony Pictures viral marketing campaign caused as much confusion as it did panic.
The upshot was that millions of people who wouldn't normally give a damn about doomsday "predictions" by ancient civilizations, suddenly did. "2012" ended up being a massive lucrative success for director Roland Emmerich -- despite the fact that to sell tickets, the movie had to sell-out science.
Science fiction movies are just that, fiction. So one can't be overly critical of any sci-fi storyline, but I was savagely critical of the movie's marketing campaign.
Through the combination of a website (the fabricated "Institute of Human Continuity"), social media, viral marketing and a multi-million dollar mass TV advertising campaign, the Maya civilization became popularized prophets of doom.
The Mayans lived in Central America (in the geographical locations of Mexico, Guatemala, Belize, El Salvador and Honduras) between 250-900 AD. It just so happens that archeologists discovered that one of their (many) calendars -- the "Long Count" -- will end its 13th "Baktun" on Dec. 21, 2012. For more on this, read the Discovery News article "2012 Doomsday is a 'Marketing Fallacy.'"
This is nothing more than a numerical coincidence, and apart from the end of their calendar likely being a spiritual event, there's no evidence to suggest the Mayans believed the end of their Long Count calendar would spell doomsday.
Unfortunately, the facts matter little to doomsayers who are trying to sell a book. In their strange little doom-filled worlds, all they need is to spark fear in the minds of a very small percentage of the population and they can promote their ideas on the weird and wonderful ways in which the world is going to end in 2012.
The best thing is that history is ambiguous enough that they can link together the Mayan "predictions" with other ancient texts (most notably the Chinese I Ching and Sumerian cuneiform scriptures) and conclude that civilizations living hundreds, or thousands, of years ago had some divine knowledge of doom in 2012.
Ever since I started writing on this bizarre topic for Universe Today in May 2008, I have received countless emails from people genuinely worried about the end of the world -- as have many other scientists. (Have a read of the article that started it all: "No Doomsday in 2012," Universe Today, May 19, 2008.) Often, they will quote some "doomsday expert" and passages from pseudo-scientific books. Evidently the "fear factor" is working. Whether or not the published doomsayers are making a ton of money from their books is open to debate -- but they populate the shelves at Barnes & Noble regardless.
Here at Discovery News and other genuine science news websites, the whole "2012 business" is easy to debunk. There is zero scientific evidence to suggest any 2012 doomsday scenario will happen. No one has ever predicted the future and that isn't about to change.
2012 will have its fair share of disasters, wars and turmoil, but none will have been predicted by a crazed doomsayer or prophesized by an ancient civilization.
In fact, to many of our readers, 2012 has become the subject of boredom and ridicule. I've received a number of messages asking why we insist on debunking theories of doom and something about "beating a dead horse."
And yet, only today, I noticed a friend on Facebook posting a message saying: Enjoy every day of 2012 like it's your last, we only have 12 months left. Sadly, she wasn't joking.
To some who believe the idiotic theories of doom, the end of the world is inevitable. Others are using this end date to justify their beliefs in astrology and conspiracy. Some are using 2012 as a soapbox for their personal ideas of global carnage. Pop stars are even singing about it.
It's becoming less about the science of debunking, and more about the science of psychology. For some reason, some people are hopelessly addicted to ideas of doom, and there's little we can do to change their minds.
Discovery News will continue its campaign of watching for 2012 doomsday theories that abuse science to manipulate people into thinking the end of the world is just around the corner. Although the majority of our readership is savvy enough to spot a conman, I am still receiving emails of concern from people who are worried about the garbage doomsayers are promoting.
Read more at Discovery News